U.S. patent number RE39,023 [Application Number 09/885,676] was granted by the patent office on 2006-03-21 for power output apparatus and method of controlling the same.
This patent grant is currently assigned to Toyota Jidosha Kabushiki Kaisha. Invention is credited to Shoichi Sasaki.
United States Patent |
RE39,023 |
Sasaki |
March 21, 2006 |
Power output apparatus and method of controlling the same
Abstract
While a ring gear shaft 126 linked with a drive shaft rotates, a
power output apparatus 110 applies a torque to a first motor MG1
attached to a sun gear shaft 125, thereby abruptly increasing a
revolving speed of an engine 150, to which a fuel injection is
stopped. A torque generated by a frictional force of, for example,
a piston in the engine 150 and working as a reaction is applied as
a braking torque to the ring gear shaft 126 via a planetary gear
120. The magnitude of the braking torque depends upon the
frictional force of, for example, the piston and can be controlled
by regulating the revolving speed of the engine 150 by means of the
first motor MG1. This control procedure enables the energy consumed
by the engine 150 to be output as a braking force to the drive
shaft.
Inventors: |
Sasaki; Shoichi (Shizuoka-ken,
JP) |
Assignee: |
Toyota Jidosha Kabushiki Kaisha
(Toyota, JP)
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Family
ID: |
17413777 |
Appl.
No.: |
09/885,676 |
Filed: |
June 21, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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Reissue of: |
08855116 |
May 13, 1997 |
05914575 |
Jun 22, 1999 |
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Foreign Application Priority Data
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Sep 13, 1996 [JP] |
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8-265187 |
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Current U.S.
Class: |
318/140; 477/3;
318/757; 318/362; 180/65.6; 477/7; 180/65.285; 180/65.22 |
Current CPC
Class: |
B60L
50/61 (20190201); B60K 6/445 (20130101); B60K
6/52 (20130101); B60L 7/003 (20130101); B60W
10/06 (20130101); B60W 20/10 (20130101); B60L
7/20 (20130101); B60W 20/00 (20130101); B60L
50/16 (20190201); B60W 10/26 (20130101); B60W
10/18 (20130101); B60L 15/007 (20130101); B60W
10/08 (20130101); Y02T 10/72 (20130101); Y02T
10/7072 (20130101); Y10S 903/903 (20130101); B60W
2540/12 (20130101); Y02T 10/645 (20130101); Y02T
10/62 (20130101); Y02T 10/6286 (20130101); Y10S
903/916 (20130101); B60K 17/356 (20130101); B60W
2710/083 (20130101); Y02T 10/70 (20130101); Y10S
903/947 (20130101); Y02T 10/64 (20130101); Y10T
477/30 (20150115); Y02T 10/7077 (20130101); B60L
2210/40 (20130101); F16H 3/727 (20130101); Y10T
477/23 (20150115); B60W 2510/244 (20130101); Y02T
10/6239 (20130101); B60K 1/02 (20130101); Y02T
10/6217 (20130101); Y02T 10/6265 (20130101); B60L
2240/423 (20130101); Y02T 10/7005 (20130101); Y02T
10/7241 (20130101) |
Current International
Class: |
H02P
7/14 (20060101); H02P 7/32 (20060101); H02P
7/34 (20060101) |
Field of
Search: |
;318/757,812,362,140-150
;310/266,112,114,103 ;475/3,5,149 ;322/11,13,40 ;477/2-9
;180/65.2,65.3,65.6 ;290/15-16,19-23 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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58401/73 |
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Jan 1975 |
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AU |
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41 24 479 |
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Jan 1993 |
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DE |
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0 725 474 |
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Aug 1996 |
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EP |
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0 775 607 |
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May 1997 |
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EP |
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0 798 844 |
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Oct 1997 |
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EP |
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A-4-322105 |
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Nov 1992 |
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JP |
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WO 89/04081 |
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May 1989 |
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WO |
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Primary Examiner: Fletcher; Marlon T.
Attorney, Agent or Firm: Oliff & Berridge, PLC
Claims
What is claimed is:
.[.1. A power output apparatus for outputting power to a drive
shaft, said power output apparatus comprising: an engine having an
output shaft; a motor having a rotating shaft and inputting and
outputting power to and from said rotating shaft; three shaft-type
power input/output means having three shafts respectively linking
said engine and said drive shaft, said three shaft-type power
input/output means inputting and outputting power to and from a
residual one shaft, based on predetermined powers input to and
output from any two shafts among said three shafts; storage battery
means for supplying and receiving an electrical energy required for
inputting and outputting power to and from said motor; and braking
control means for controlling said engine and said motor, based on
a changing state of said storage battery means, in order to enable
a braking force to be applied to said drive shaft..].
.[.2. A power output apparatus in accordance with claim 1, wherein
said braking control means comprises means for enabling said motor
to carry out a regenerative operation, thereby applying a braking
force to said drive shaft..].
.[.3. A power output apparatus in accordance with claim 1, wherein
said braking control means comprises means for enabling said motor
to carry out a power operation, thereby applying a braking force to
said drive shaft..].
.[.4. A power output apparatus in accordance with claim 1, wherein
said braking control means comprises means for controlling said
motor, in order to enable said motor to motor said engine..].
.[.5. A power output apparatus in accordance with claim 1, wherein
said braking control means comprises means for locking up said
motor..].
.[.6. A power output apparatus in accordance with claim 1, said
power output apparatus further comprising: a second motor for
inputting and outputting power to and from said drive shaft, in
addition to said motor working as a first motor, wherein said
storage battery means comprises means for supplying and receiving
an electrical energy required for inputting and outputting power to
and from said second motor, said braking control means comprising
means for controlling said engine, said first motor, and said
second motor, in order to enable a braking force to be applied to
said drive shaft..].
7. A power output apparatus .[.in accordance with claim 6.].
.Iadd.for outputting power to and from said rotating
shaft.Iaddend., said power output apparatus .[.further.].
comprising: .Iadd.an engine having an output shaft; a motor having
a rotating shaft and inputting and outputting power to and from
said rotating shaft; three shaft-type power input/output means
having three shafts, including the output shaft and the rotating
shaft, respectively linking said engine and said drive shaft, said
three shaft-type power input/output means inputting and outputting
power to and from a residual one shaft, based on predetermined
powers input to and output from any two shafts among said three
shafts; storage battery means for supplying and receiving an
electrical energy required for inputting and outputting to and from
said motor; .Iaddend..[.and.]. .Iadd.braking control means for
controlling said engine and said motor, based on a charging state
of said storage battery means, in order to enable a braking force
to be applied to said drive shaft; a second motor for inputting and
outputting power to and from said drive shaft, in addition to said
motor working as a first motor; and .Iaddend. charging state
detection means for detecting the charging state of said storage
battery means, .Iadd.wherein said storage battery means comprises
means for supplying and receiving an electrical energy required for
inputting and outputting power to and from said second motor, said
braking control means comprising means for controlling said engine,
said first motor, and said second motor, in order to enable a
braking force to be applied to said drive shaft .Iaddend.
.[.wherein said braking control means comprises means for
controlling said engine, said first motor, and said second motor.].
based on the charging state of said storage battery means detected
by said charging state detection means, thereby applying a braking
force to said drive shaft.
8. A power output apparatus .[.in accordance with claim 7, wherein
said braking control means comprises.]. .Iadd.for outputting power
to a drive shaft, said power output apparatus comprising: an engine
having an output shaft; a motor having a rotating shaft and
inputting and outputting power to and from said rotating shaft;
three shaft-type power input/output means having three shafts
respectively linking said engine and said drive shaft, said three
shaft-type power input/output means inputting and outputting power
to and from a residual one shaft, based on predetermined powers
input to and output from any two shafts among said three shafts;
storage battery means for supplying and receiving an electrical
energy required for inputting and outputting power to and from said
motor; braking control means for controlling said engine and said
motor, based on a charging state of said storage battery means, in
order to enable a braking force to be applied to said drive shaft;
a second motor for inputting and outputting power to and from said
drive shaft, in addition to said motor working as a first motor,
wherein said storage battery means comprises means for supplying
and receiving an electrical energy required for inputting and
outputting power to and from said second motor; and charging state
detection means for detecting the charging state of said storage
battery means, wherein said braking control means comprises means
for controlling said engine, said first motor, and said second
motor based on the charging state of said storage battery means
detected by said charging state detection means, thereby applying a
braking force to said drive shaft, and .Iaddend.means for
regulating the charging state of said storage battery means
detected by said charging state detection means to be within a
predetermined range.
9. A power output apparatus .[.in accordance with claim 6, wherein
said braking control means comprises.]. .Iadd.for outputting power
to a drive shaft, said power output apparatus comprising: .Iaddend.
an engine having an output shaft; a motor having a rotating shaft
and inputting and outputting power to and from said rotating shaft;
three shaft-type power input/output means having three shafts
respectively linking said engine and said drive shaft, said three
shaft-type power input/output means inputting and outputting power
to and from a residual one shaft, based on predetermined powers
input to and output from any two shafts among said three shafts;
storage battery means for supplying and receiving an electrical
energy required for inputting and outputting power to and from said
motor; braking control means for controlling said engine and said
motor, based on a charging state of said storage battery means, in
order to enable a braking force to be applied to said drive shaft;
and a second motor for inputting and outputting power to and from
said drive shaft, in addition to said motor working as a first
motor, wherein said storage battery means comprises means for
supplying and receiving an electrical energy required for inputting
and outputting power to and from said second motor, and said
braking control means comprises means for controlling said engine,
said first motor, and said second motor, in order to enable a
braking force to be applied to said drive shaft, and .Iaddend.means
for controlling said second motor in order to enable said second
motor to apply a braking force to said drive shaft, while
controlling said first motor in order to make power input to and
output from said first motor equal to zero.
.[.10. A power output apparatus in accordance with claim 6, wherein
said braking control means comprises means for controlling said
second motor in order to enable said second motor to apply a
braking force to said drive shaft, while controlling said engine
and said first motor in order to set a driving state of said engine
to a predetermined operating condition..].
11. A power output apparatus .[.in accordance with claim 10,.].
.Iadd.for outputting power to a drive shaft, .Iaddend.said power
output apparatus .[.further.]. comprising: .Iadd.an engine having
an output shaft; a motor having a rotating shaft and inputting and
outputting power to and from said rotating shaft; three shaft-type
power input/output means having three shafts, including the output
shaft and the rotating shaft, respectively linking said engine and
said drive shaft, said three shaft-type power input/output means
inputting and outputting power to and from a residual one shaft,
based on predetermined powers input to and output from any two
shafts among said three shafts; storage battery means for supplying
and receiving an electrical energy required for inputting and
outputting power and from said motor; .Iaddend..[.and.].
.Iadd.braking control means for controlling said engine and said
motor, based on a charging state of said storage battery means, in
order to enable a braking force to be applied to said drive shaft;
a second motor for inputting and outputting power to and from said
drive shaft, in addition to said motor working as a first motor;
.Iaddend. driving state detection means for detecting a driving
state of said drive shaft; and braking-time driving state setting
means for setting .[.the redetermined.]. .Iadd.a predetermined
.Iaddend.operating condition based on the driving state of said
drive shaft detected by said driving state detection means,
.Iadd.wherein said storage battery means comprises means for
supplying and receiving an electrical energy required for inputting
and outputting power to and from said second motor, said braking
control means comprising means for controlling said engine, said
first motor, and said second motor, in order to enable a braking
force to be applied to said drive shaft, such that said second
motor is enabled to apply a braking force to said drive shaft,
while controlling said engine and said first motor in order to set
a driving state of said engine to the predetermined operating
condition.Iaddend..
.[.12. A power output apparatus in accordance with claim 10,
wherein the driving state of said engine represents a revolving
speed of said output shaft of said engine..].
.[.13. A power output apparatus in accordance with claim 6, wherein
said braking control means comprises means for controlling said
first motor, in order to enable said first motor to motor said
engine..].
14. A power output apparatus .[.in accordance with claim 6, wherein
said braking control means comprises.]. .Iadd.for outputting power
to a drive shaft, said power output apparatus comprising: an engine
having an output shaft; a motor having a rotating shaft and
inputting and outputting power to and from said rotating shaft;
three shaft-type power input/output means having three shafts
respectively linking said engine and said drive shaft, said three
shaft-type power input/output means inputting and outputting power
to and from a residual one shaft, based on predetermined powers
input to and output from any two shafts among said three shafts;
storage battery means for supplying and receiving an electrical
energy required for inputting and outputting power to and from said
motor; braking control means for controlling said engine and said
motor, based on a charging state of said storage battery means, in
order to enable a braking force to be applied to said drive shaft;
and a second motor for inputting and outputting power to and from
said drive shaft, in addition to said motor working as a first
motor, wherein said storage battery means comprises means for
supplying and receiving an electrical energy required for inputting
and outputting power to and from said second motor, and said
braking control means comprises means for controlling said engine,
said first motor, and said second motor, in order to enable a
braking force to be applied to said drive shaft, and .Iaddend.means
for controlling said first motor and said second motor, in order to
enable an electrical energy regenerated by said second motor to be
identical with an electrical energy consumed by said first
motor.
.[.15. A power output apparatus in accordance with claim 1, said
power output apparatus further comprising: a second motor for
inputting and outputting power to and from said output shaft of
said engine, in addition to said motor working as a first motor,
wherein said storage battery means comprises means for supplying
and receiving an electrical energy required for inputting and
outputting power to and from said second motor, said braking
control means comprising means for controlling said engine, said
first motor, and said second motor, in order to enable a braking
force to be applied to said drive shaft..].
16. A power output apparatus .[.in accordance with claim 15.]. ,
.Iadd.for outputting power to a drive shaft.Iaddend., said power
output apparatus .[.further.]. comprising: .Iadd.an engine having
an output shaft; a motor having a rotating shaft and inputting and
outputting power to and from said rotating shaft; three shaft-type
power input/output means having three shafts, including the output
shaft and the rotating shaft, respectively linking said engine and
said drive shaft, said three shaft-type power input/output means
inputting and outputting power to and from a residual one shaft,
based on predetermined powers input to and output from any two
shafts among said three shafts; storage battery means for supplying
and receiving an electrical energy required for inputting and
outputting power to and from said motor; .Iaddend..[.and.].
.Iadd.braking control means for controlling said engine and said
motor, based on a charging state of said storage battery means, in
order to enable a braking force to be applied to said drive shaft;
a second motor for inputting and outputting power to and from said
output shaft of said engine, in addition to said motor working as a
first motor; and .Iaddend. charging state detection means for
detecting the charging state of said storage battery means,
.Iadd.wherein said storage battery means comprises means for
supplying and receiving an electrical energy required for inputting
and outputting power to and from said second motor, .Iaddend.
.[.wherein said braking control means comprises means for
controlling said engine, said first motor, and said second motor.].
.Iadd.said braking control means comprising means for controlling
said engine, said first motor, and said second motor, in order to
enable a braking force to be applied to said drive shaft
.Iaddend.based on the charging state of said storage battery means
detected by said charging state detection means.
17. A power output apparatus .[.in accordance with claim 16,
wherein said braking control means comprises.]. .Iadd.for
outputting power to a drive shaft, said power output apparatus
comprising: an engine having an output shaft; a motor having a
rotating shaft and inputting and outputting power to and from said
rotating shaft; three shaft-type power input/output means having
three shafts respectively linking said engine and said drive shaft,
said three shaft-type power input/output means inputting and
outputting power to and from a residual one shaft, based on
predetermined powers input to and output from any two shafts among
said three shafts; storage battery means for supplying and
receiving an electrical energy required for inputting and
outputting power to and from said motor; braking control means for
controlling said engine and said motor, based on a charging state
of said storage battery means, in order to enable a braking force
to be applied to said drive shaft; a second motor for inputting and
outputting power to and from said output shaft of said engine, in
addition to said motor working as a first motor, wherein said
storage battery means comprises means for supplying and receiving
an electrical energy required for inputting and outputting power to
and from said second motor; charging state detection means for
detecting the charging state of said storage battery means, wherein
said braking control means comprises means for controlling said
engine, said first motor, and said second motor in order to enable
a braking force to be applied to said drive shaft based on the
charging state of said storage battery means detected by said
charging state detection means, and means for regulating the
charging state of said storage battery means detected by said
charging state detection means to be within a predetermined range.
.Iaddend.
.[.18. A power output apparatus in accordance with claim 15,
wherein said braking control means comprises means for controlling
said first motor in order to enable said first motor to motor said
engine, while controlling said second motor in order to enable said
second motor to apply a braking force to said output shaft of said
engine..].
19. A power output apparatus .[.in accordance with claim 15,
wherein said braking control means comprises.]. .Iadd.for
outputting power to a drive shaft, said power output apparatus
comprising:.Iaddend. .Iadd.an engine having an output shaft; a
motor having a rotating shaft and inputting and outputting power to
and from said rotating shaft; three shaft-type power input/output
means having three shafts respectively linking said engine and said
drive shaft, said three shaft-type power input/output means
inputting and outputting power to and from a residual one shaft,
based on predetermined powers input to and output from any two
shafts among said three shafts; storage battery means for supplying
and receiving an electrical energy required for inputting and
outputting power to and from said motor; braking control means for
controlling said engine and said motor, based on a charging state
of said storage battery means, in order to enable a braking force
to be applied to said drive shaft; and a second motor for inputting
and outputting power to and from said output shaft of said engine,
in addition to said motor working as a first motor, wherein said
storage battery means comprises means for supplying and receiving
an electrical energy required for inputting and outputting power to
and from said second motor, and said braking control means
comprises means for controlling said engine, said first motor, and
said second motor, in order to enable a braking force to be applied
to said drive shaft, and means for controlling said first motor and
said second motor, in order to enable an electrical energy
regenerated by said second motor to be identical with an electrical
energy consumed by said first motor.
.[.20. A method of controlling a power output apparatus for
outputting power to a drive shaft, said method comprising the steps
of: (a) providing (1) an engine having an output shaft; (2) a first
motor having a rotating shaft and inputting and outputting power to
and from said rotating shaft; (3) a second motor for inputting and
outputting power to and from said drive shaft; and (4) three
shaft-type power input/output means having three shafts
respectively linking said engine and said drive shaft, said three
shaft-type power input/output means inputting and outputting power
to and from a residual one shaft, based on predetermined powers
input to and output from any two shafts among said three shafts;
(b) controlling said second motor, in order to enable said second
motor to apply a braking force to said drive shaft; and (c)
controlling said engine and said first motor, in order to set a
driving state of said engine to a predetermined operating
condition..].
21. A method of controlling a power output apparatus for outputting
power to a drive shaft, said method comprising the steps of: (a)
providing (1) an engine having an output shaft; (2) a first motor
having a rotating shaft and inputting and outputting power to and
from said rotating shaft; (3) a second motor for inputting and
outputting power to and from said drive shaft; (4) three shaft-type
power input/output means having three shafts respectively linking
said engine and said drive shaft, said three shaft-type power
input/output means inputting and outputting power to and from a
residual one shaft, based on predetermined powers input to and
output from any two shafts among said three shafts; and (5) storage
battery means for supplying and receiving an electrical energy
required for inputting and outputting power to and from said first
motor, and supplying and receiving an electrical energy required
for inputting and outputting power to and from said second motor;
and (b) controlling said engine, said first motor, and said second
motor, in order to apply a braking force to said drive shaft while
keeping a charging state of said storage battery means within a
predetermined range.
.Iadd.22. A method of controlling a power output apparatus, for
outputting power to a drive shaft, having an engine with an output
shaft, a motor with a rotating shaft, and three shaft-type power
input/output means having three shafts respectively linking said
engine and said drive shaft, a second motor, the method comprising:
inputting and outputting power to and from said rotating shaft;
inputting and outputting power, via said three shaft-type power
input/output means, to and from a residual one shaft, based on
predetermined powers input to and output from any two shafts among
said three shafts; supplying and receiving an electrical energy,
from a storage battery means, required for inputting and outputting
power to and from said motor; controlling, using a braking control
means, said engine and said motor, based on a charging state of
said storage battery means, in order to enable a braking force to
be applied to said drive shaft; inputting and outputting power to
and from said drive shaft via the second motor, in addition to said
motor working as a first motor; supplying and receiving an
electrical energy, from said battery storage means, required for
inputting and outputting power to and from said second motor;
detecting the charging state of said storage battery means;
controlling, via said braking control means, said engine, said
first motor, and said second motor based on the detected charging
state of said storage battery means, to thereby apply a braking
force to said drive shaft; and regulating the charging state of
said storage battery means to be within a predetermined range.
.Iaddend.
.Iadd.23. A method of controlling a power output apparatus, for
outputting power to a drive shaft, having an engine with an output
shaft, a motor with a rotating shaft, a second motor, and three
shaft-type power input/output means having three shafts
respectively linking said engine and said drive shaft, said method
comprising: inputting and outputting power to and from said
rotating shaft; inputting and outputting power, via said three
shaft-type power input/output means, to and from a residual one
shaft, based on predetermined powers input to and output from any
two shafts among said three shafts; supplying and receiving an
electrical energy, from a storage battery means, required for
inputting and outputting power to and from said motor; controlling,
using a braking control means, said engine and said motor, based on
a charging state of said storage battery means, in order to enable
a braking force to be applied to said drive shaft; inputting and
outputting power, from a second motor, to and from said output
shaft of said engine, in addition to said motor working as first
motor; supplying and receiving an electrical energy, from said
storage battery means, required for inputting and outputting power
to and from said second motor; controlling said engine, said first
motor, and said second motor, using the braking control means, in
order to enable a braking force to be applied to said drive shaft;
detecting a charging state of said storage battery means using a
charging state detection means, wherein controlling said engine,
said first motor, and said second motor is based on the charging
state of said storage battery means detected by said charging state
detection means; and regulating the charging state of said storage
battery means detected by said charging state detection means to be
within a predetermined range. .Iaddend.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a power output apparatus and a
method of controlling the same. More specifically the present
invention pertains to a power output apparatus for outputting power
to a drive shaft and a method of controlling such a power output
apparatus.
2. Description of the Prior Art
Proposed power output apparatus include an internal combustion
engine, a planetary gear as three shaft-type power input/output
means, two motors (a first motor and a second motor) that can input
and output powers, a battery supplying and receiving electrical
energy required for inputting and outputting powers to and from the
two motors, and a controller for controlling the internal
combustion engine and the two motors (for example, Federal Republic
of Germany Patent Application DE4124479A1). In this known power
output apparatus, a crankshaft or an output shaft of the internal
combustion engine is linked with a sun gear shaft, which connects
with a sun gear of the planetary gear, via one-way clutch, whereas
a carrier shaft, which connects with a planetary carrier of the
planetary gear, is linked with driving wheels via a differential
gate. A rotor of the second motor is attached to the sun gear
shaft, so that power is transmitted between the second motor and
the sun gear shaft. A rotor of the first motor is attached to a
ring gear shaft, which connects with a ring gear of the planetary
gear, so that power is transmitted between the first motor and the
ring gear shaft. The power output apparatus further includes a
clutch that connects the sun gear shaft with the ring gear shaft
and thereby integrates the three shafts (sun gear shaft, ring gear
shaft, and carrier shaft) linked with the planetary gear.
In this proposed power output apparatus, the sum of the power
output from the internal combustion engine and the power input to
or output from the second motor is given to the planetary gear,
while the first motor gives a reaction force to the ring gear. This
enables the power to be output to the carrier shaft and thereby
drives the driving wheels. In order to give a braking force to the
driving wheels, the clutch is connected to integrate the three
shafts of the planetary gear and make the first motor and the
second motor function as generators.
In case that the battery is in a fully charged state, however, the
known power output apparatus can not make the first motor and the
second motor function as generators nor output the braking force to
the driving wheels. In this power output apparatus, the crankshaft
and the sun gear shaft are connected to each other via the one-way
clutch, so that a torque for rotating the internal combustion
engine can not be transmitted from the sun gear shaft to the
crankshaft. Namely the braking force can not be output to the
driving wheels in the form of engine brake. Additional devices,
such as a hydraulic circuit and an actuator, are required to ensure
the operation of the clutch connecting the sun gear shaft to the
ring gear shaft. This undesirably makes the whole power output
apparatus complicated and bulky.
SUMMARY OF THE INVENTION
One object of the present invention is thus to provide a power
output apparatus that outputs a power from an engine to a drive
shaft via three shaft-type power input/output means which inputs
and outputs powers regulated by a motor and that controls the motor
in order to enable energy consumed by the engine to be output to
the drive shaft as a braking force, as well as a method of
controlling such a power output apparatus.
Another object of the present invention is to provide a power
output apparatus that outputs a braking force to the drive shaft
while storage battery means included in the apparatus is charged,
discharged, or intact according to the charging state of the
storage battery means, as well as a method of controlling such a
power output apparatus.
Still another object of the present invention is to simplify the
structure of and reduce the size of the power output apparatus.
At least part of the above and the other related objects is
realized by a power output apparatus of the present invention for
outputting powers to a drive shaft, the power output apparatus
comprises: an engine having an output shaft; a motor having a
rotating shaft and inputting and outputting power to and from the
rotating shaft; three shaft-type power input/output means having
three shafts respectively linked with the drive shaft, the output
shaft, and the rotating shaft, the three shaft-type power
input/output means inputting said outputting power to and from a
residual one shaft, based on predetermined powers input to and
output from any two shafts among the three shafts; storage battery
means for supplying and receiving an electrical energy required for
inputting and outputting power to and from the motor; and braking
control means for controlling the engine and the motor; in order to
enable a braking force to be applied to the drive shaft.
The power output apparatus of the present invention controls the
engine and the motor, in order to enable powers input to and output
from the output shaft of the engine and the rotating shaft of the
motor to be applied to the drive shaft via the three shaft-type
power input/output means. This structure thus allows the engine and
the motor to output a braking force to the drive shaft.
In the power output apparatus of the present invention, the braking
control means may include means for enabling the motor to carry out
a regenerative operation, thereby applying a braking force to the
drive shaft, or means for enabling the motor to carry out a power
operation, thereby applying a braking force to the drive shaft.
This preferable structure enables a braking force to be output to
the drive shaft, while charging or discharging storage battery
means.
In accordance with one aspect of the power output apparatus of the
present invention, wherein the braking control means may include
means for controlling the motor, in order to enable the motor to
motor the engine. This structure enables energy used for motoring
the engine to be output as a braking force to the drive shaft.
In accordance with another aspect of the power output apparatus of
the present invention, wherein the braking control means may
includes means for locking up the motor. This structure outputs a
braking force to the drive shaft in the form of engine brake.
In accordance with still another aspect of the power output
apparatus of the present invention, the power output apparatus
further comprises a second motor for inputting and outputting power
to and from the drive shaft, in addition to the motor working as a
first motor; wherein the storage battery means comprises means for
supplying and receiving an electrical energy required for inputting
and outputting power to and from the second motor; the braking
control means comprising means for controlling the engine, the
first motor, and the second motor, in order to enable a braking
force to be applied to the drive shaft. This structure (a) enables
not only the engine and the first motor but the second motor to
output a braking force to the drive shaft.
In accordance with one aspect of this structure (a), the power
output apparatus further comprises charging the detection means for
detecting a charging state of the storage battery means; wherein
the braking control means comprises means for controlling the
engine, the first motor, and the second motor based on the charging
state of the storage battery means detected by the charging state
detection means, thereby applying a braking force to the drive
shaft. This structure sets the charging state of the storage
battery means at a desired level. In this structure, the braking
control means may include means for regulating the charging state
of the storage battery means detected by the charging state
detection means to be within a predetermined range. This structure
keeps the charging state of the storage battery means within a
predetermined range.
In accordance with another aspect of the structure (a), wherein the
braking control means comprises means for controlling the second
motor in order to enable the second motor to apply a braking force
to the drive shaft, while controlling the first motor in order to
make power input to and output from the first motor equal to zero.
The three shaft-type power input/output means is stably kept in the
state of least energy consumed by the first motor and the engine.
This maximizes the energy regenerated by the second motor.
In accordance with still another aspect of the structure (a),
wherein the braking control means comprises means for controlling
the second motor in order to enable the second motor to apply a
braking force to the drive shaft, while controlling the engine and
the first motor in order to set a driving state of the engine to a
predetermined operating condition. This structure sets the engine
to a desired driving state in the course of braking control. The
driving state of the engine may represent a revolving speed of the
output shaft of the engine. In this structure, the power output
apparatus may include: driving state detection means for detecting
a driving state of the drive shaft, and braking-time driving state
settling means for setting the predetermined operating condition
based on the driving state of the drive shaft detected by the
driving state detection means. This structure varies the driving
state of the engine based on the driving state of the drive
shaft.
In accordance with still another aspect of the structure (a),
wherein the braking control means comprises means for controlling
the first motor, in order to enable the first motor to motor the
engine. This structure enables energy used for motoring the engine
to be output as a braking force to the drive shaft.
In accordance with still another aspect of the structure (a),
wherein the braking control means comprises means for controlling
the first motor and the second motor, in order to enable an
electrical energy regenerated by the second motor to be identical
with an electrical energy consumed by the first motor. This
structure enables a braking force to be output to the drive shaft,
irrespective of the charging state of the storage battery
means.
In accordance with still another aspect of the power output
apparatus of the present invention, the power output apparatus may
include a second motor for inputting and outputting power to and
from the output shaft of the engine, in addition to the motor
working as a first motor; wherein the storage battery means
comprises means for supplying and receiving an electrical energy
required for inputting and outputting power to and from the second
motor; the braking control means comprising means for controlling
the engine, the first motor, and the second motor, in order to
enable a braking force to be applied to the drive shaft. This
structure (b) regulates the power input to and output from the
second motor, thereby applying a braking force to the drive shaft,
while the engine and the fist motor also output a braking force to
the drive shaft.
In accordance with one aspect of the structure (b), the power
output apparatus may include charging state detection means for
detecting a charging state of the storage battery means; wherein
the braking control means comprises means for controlling the
engine, the first motor, and the second motor based on the charging
state of the storage battery means detected by the charging state
detection means. This structure sets the charging state of the
storage battery means at a desired level. In this structure, the
braking control means may include means for regulating the charging
state of the storage battery means detected by the charging state
detection means to be within a predetermined range. This structure
keeps the charging state of the storage battery means within a
predetermined range.
In accordance with another aspect of the structure (b), wherein the
braking control means may include means for controlling the first
motor in order to enable the first motor to motor the engine, while
controlling the second motor in order to enable the second motor to
apply a braking force to the output shaft of the engine. This
structure enables a greater braking force to be output to the drive
shaft.
In accordance with still another aspect of the structure (b),
wherein the braking control means comprises means for controlling
the first motor and the second motor, in order to enable an
electrical energy regenerated by the second motor to be identical
with an electrical energy consumed by the first motor. This
structure enables a braking force to be output to the drive shaft,
irrespective of the charging state of the storage battery
means.
At least part of the above and the other related objects is
realized by a first method of controlling a power output apparatus
for outputting power to a drive shaft, the first method comprises
the steps of: (a) providing (1) an engine having an output shaft,
(2) a motor having a rotating shaft and inputting and outputting
power to and from the rotating shaft, and (3) three shaft-type
power input/output means having three shafts respectively linked
with the drive shaft, the output shaft, and the rotating shaft, the
three shaft-type power input/output means inputting and outputting
power to and from a residual one shaft, based on predetermined
powers input to and output from any two shafts among the three
shafts; and (b) controlling the motor, in order to enable the motor
to motor the engine, thereby applying a braking force to the drive
shaft.
The first method of controlling a power output apparatus of the
present invention enables energy used for motoring the engine to be
output as a braking force to the drive shaft.
At least part of the above and the other related objects is
realized by a second method of controlling a power output apparatus
for outputting power to a drive shaft, the second method comprises
the steps of: (a) providing (1) an engine having an output shaft,
(2) a first motor having a rotating shaft and inputting and
outputting powers to and from the rotating shaft, (3) a second
motor for inputting and outputting power to and from the drive
shaft, and (4) three shaft-type power input/output means having
three shafts respectively linked with the drive shaft, the output
shaft, and the rotating shaft, the three shaft-type power
input/output means inputting and outputting power to and from a
residual one shaft, based on predetermined powers input to and
output from any two shafts among the three shafts; (b) controlling
the second motor, in order to enable the second motor to apply a
braking force to the drive shaft; and (c) controlling the engine
and the first motor, in order to set a driving state of the engine
to a predetermined operating condition.
The second method of controlling a power output apparatus of the
present invention enables the second motor to output a braking
force to the drive shaft, while setting the engine to a desired
driving state.
At least part of the above and the other related objects is
realized by a third method of controlling a power output apparatus
for outputting power to a drive shaft, the third method comprises
the steps of: (a) providing (1) an engine having an output shaft,
(2) a first motor having a rotating shaft and inputting and
outputting power to and from the rotating shaft, (3) a second motor
for inputting and outputting power to and from the drive shaft, (4)
three shaft-type power input/output means having three shafts
respectively linked with the drive shaft, the output shaft, and the
rotating shaft, the three shaft-type power input/output means
inputting and outputting power to and from a residual one shaft,
based on predetermined powers input to and output from any two
shafts among the three shafts, and (5) storage battery means for
supplying and receiving an electrical energy required for inputting
and outputting power to and from the first motor, and supplying and
receiving an electrical energy required for inputting and
outputting power to and from the second motor; and (b) controlling
the engine, the first motor, and the second motor, in order to
apply a braking force to the drive shaft while keeping a charging
state of the storage battery means within a predetermined
range.
The third method of controlling a power output apparatus of the
present invention enables the engine, the first motor, and the
second motor to output a braking force to the drive shaft, while
keeping the charging state of the storage battery means within a
predetermined range.
These and other objects, features, aspects, and advantages of the
present invention will become apparent from the following detailed
description of the preferred embodiments with the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 schematically illustrates structure of a power output
apparatus 110 embodying the present invention;
FIG. 2 is an enlarged view illustrating an essential part of the
power output apparatus 110 of the embodiment;
FIG. 3 schematically illustrates general structure of a vehicle
with the power output apparatus 110 of the embodiment incorporated
therein;
FIG. 4 is a graph showing the operation principle of the power
output apparatus 110 of the embodiment;
FIG. 5 is a nomogram showing the relationship between the revolving
speed and the torque on the three shafts linked with the planetary
gear 120 in the power output apparatus 110 of the embodiment;
FIG. 6 is a nomogram showing the relationship between the revolving
speed and the torque on the three shafts linked with the planetary
gear 120 in the power output apparatus 110 of the embodiment;
FIG. 7 is a nomogram showing the state when no torque is
applied;
FIG. 8 is a nomogram showing the state when the first motor MG1 is
controlled to carry out the regenerative operation and thereby
enable a braking force to be applied to the ring gear shaft
126;
FIG. 9 is a nomogram showing the state when the first motor MG1 is
controlled to carry out the power operation and thereby enable a
braking force to be applied to the ring gear shaft 126.
FIG. 10 is a graph showing the revolving speed Ne and the torque Te
working as a reaction while the engine 150 is raced;
FIG. 11 is a flowchart showing a braking control routine executed
by the control CPU 190 of the controller 180 in the first
embodiment;
FIG. 12 is a nomogram showing the state when a braking force is
applied to the ring gear shaft 126 while the first motor MG1 is in
a lock-up state;
FIGS. 13 and 14 are flowcharts showing a torque control routine in
a braking state executed by the control CPU 190 of the controller
180 in the first embodiment;
FIG. 15 is a graph showing the relationship between the remaining
charge BRM of the battery 194 and the chargeable electrical power
with a threshold value Bref;
FIG. 16 is a flowchart showing a control routine of the first motor
MG1 executed by the control CPU 190 of the controller 180;
FIG. 17 is a flowchart showing a control routine of the second
motor MG2 executed by the control CPU 190 of the controller
180;
FIG. 18 is a nomogram showing the state when a braking force is
applied to the ring gear shaft 126 while the battery 194 is charged
in the first embodiment;
FIG. 19 is a graph showing the relationship between the revolving
speed Ne, the torque Te working as a reaction, and the braking
energy Pr while the engine 150 is raced;
FIG. 20 is a nomogram showing the state when a braking force is
applied to the ring gear shaft 126 while the battery 194 is intact
in the first embodiment;
FIG. 21 is a flowchart showing part of a modified torque control
routine in a braking state;
FIG. 22 is a nomogram showing the state when the modified torque
control routine in the braking state is carried out;
FIG. 23 is a graph showing the relationship between the
predetermined revolving speed Nst and the revolving speed Nr of the
ring gear shaft 126;
FIG. 24 is a flowchart showing a continuous braking control routine
executed by the control CPU 190 of the controller 180 in the first
embodiment;
FIG. 25 schematically illustrates another power output apparatus
110A as a modified example of the first embodiment;
FIG. 26 schematically illustrates still another power output
apparatus 110B as another modified example of the first
embodiment;
FIG. 27 schematically illustrates structure of an essential part of
another power output apparatus 110C as a second embodiment
according to the present invention;
FIG. 28 is a nomogram showing the relationship between the
revolving speed and the torque on the three shafts linked with the
planetary gear 120 in the power output apparatus 110C of the second
embodiment;
FIG. 29 is a nomogram showing the relationship between the
revolving speed and the torque on the three shafts linked with the
planetary gear 120 in the power output apparatus 110C of the second
embodiment;
FIGS. 30 and 31 are flowcharts showing a torque control routine in
a braking state executed by the control CPU 190 of the controller
180 in the second embodiment;
FIG. 32 is a nomogram showing the state when a braking force is
applied to the ring gear shaft 126 while the battery 194 is charged
in the second embodiment;
FIG. 33 is a nomogram showing the state when a braking force is
applied to the ring gear shaft 126 while the battery 194 is intact
in the second embodiment;
FIG. 34 is a flowchart showing a continuous braking control routine
executed by the control CPU 190 of the controller 180 in the second
embodiment;
FIG. 35 schematically illustrates another power output apparatus
110D as a modified example of the second embodiment;
FIG. 36 schematically illustrates still another power output
apparatus 110E as another modified example of the second
embodiment; and
FIG. 37 schematically illustrates structure of a four-wheel-drive
vehicle with a power output apparatus 110F; which is equivalent to
the power output apparatus 110 of the first embodiment.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Some modes of carrying out the present invention are described as
preferred embodiments. FIG. 1 schematically illustrates structure
of a power output apparatus 110 embodying the present invention;
FIG. 2 is an enlarged view illustrating as essential part of the
power output apparatus 110 of the embodiment; and FIG. 3
schematically illustrates general structure of a vehicle with the
power output apparatus 110 of the embodiment incorporated therein.
The general structure of the vehicle is described first for the
convenience of explanation.
Referring to FIG. 3, the vehicle is provided with an engine 150
which consumes gasoline as a fuel and outputs power. The air
ingested from an air supply system via a throttle valve 166 is
mixed with a fuel, that is, gasoline in this embodiment, injected
from a fuel injection valve 151. The air/fuel mixture is supplied
into a combustion chamber 152 to be explosively ignited and burned.
Linear motion of a piston 154 pressed down by the explosion of the
air/fuel mixture is converted to rotational motion of a crankshaft
156. The throttle valve 166 is driven to open and close by an
actuator 168. An ignition plug 162 converts a high voltage applied
from an igniter 158 via a distributor 160 to a spark, which
explosively ignites and combusts the air/fuel mixture.
Operation of the engine 150 is controlled by an electronic control
unit (hereinafter referred to as EFIECU) 170. The EFIECU 170
receives information form various sensors, which detect operating
conditions of the engine 150. These sensors include a throttle
valve position sensor 167 for detecting a valve travel or position
of the throttle valve 166, a manifold vacuum sensor 172 for
measuring a load applied to the engine 150, a water temperature
sensor 174 for measuring the temperature of cooling water in the
engine 150, and a speed sensor 176 and an angle sensor 178 mounted
on the distributor 160 for measuring the revolving speed (the
number of revolutions per a predetermined time period) and the
rotational angle of the crankshaft 156. A starter switch 179 for
detecting a starting condition ST of an ignition key (not shown) is
also connected to the EFIECU 170. Other sensors and switches
connecting with the EFIECU 170 are omitted from the
illustration.
The crankshaft 156 of the engine 150 is mechanically linked with a
power transmission gear 111, which has a drive shaft 112 as a
rolling axis, via a planetary gear 120 and first and second motors
MG1 and MG2 (described later in detail). The power transmission
gear 111 is further linked with a differential gear 114, so that
the power output from the power output apparatus 110 is eventually
transmitted to left and right driving wheels 116 and 118. The first
motor MG1 and the second motor MG2 are electrically connected to
and controlled by a controller 180. The controller 180 includes an
internal control CPU and receives inputs from a gearshaft position
sensor 184 attached to a gearshift 182, an accelerator position
sensor 164a attached to an acceleration pedal 164, and a brake
pedal position sensor 165a attached to a brake petal 165, as
described later in detail. The controller 180 sends and receives a
variety of data and information to and from the EFIECU 170 through
communication. Details of the control procedure including a
communication protocol will be described later.
Referring to FIGS. 1 and 2, the power output apparatus 110 of the
embodiment primarily includes the engine 150, the planetary gear
120 having a planetary carrier 124 mechanically linked with the
crankshaft 156 of the engine 150, the first motor MG1 linked with a
sun gear 121 of the planetary gear 120, the second motor MG2 linked
with a ring gear 122 of the planetary gear 120, and the controller
180 for driving and controlling the first and the second motors MG1
and MG2.
The following describes structure of the planetary gear 120 and the
first and second motors MG1 and MG2 based on the drawing of FIG. 2.
The planetary gear 120 includes the sun gear 121 linked with a
hollow sun gear shaft 125 which the crankshaft 156 passes through,
the ring gear 122 linked with a ring gear shaft 126 coaxial with
the crankshaft 156, a plurality of planetary pinion gears 123
arranged between the sun gear 121 and the ring gear 122 to revolve
around the sun gear 121 while rotating on its axis, and the
planetary carrier 124 connecting with one end of the crankshaft 156
to support the rotating shafts of the planetary pinion gears 123.
In the planetary gear 120, three shafts, that is, the sun gear
shaft 125, the ring gear shaft 126, and the crankshaft 156
respectively connecting with the sun gear 121, the ring gear 122,
and the planetary carrier 124, work as input and output shafts of
the power. Determination of the powers input to and output from any
two shafts among the three shafts automatically determines the
power input to and output from the residual one shaft. The details
of the input and output operations of the power into and from the
three shafts of the planetary gear 120 will be discussed later.
A power feed gear 128 for taking out the power is linked with the
ring gear 122 and arranged on the side of the first motor MG1. The
power feed gear 128 is further connected to the power transmission
gear 111 via a chain belt 129, so that the power is transmitted
between the power feed gear 128 and the power transmission gear
111.
The first motor MG1 is constructed as a synchronous motor-generated
and includes a rotor 132 having a plurality of permanent magnets
135 on its outer surface and a stator 133 having three-phase coils
134 wound thereon to form a revolving magnetic field. The rotor 132
is linked with the sun gear shaft 125 connecting with the sun gear
121 of the planetary gear 120. The stator 133 is prepared by laying
thin plates of non-directional electromagnetic steel one upon
another and is fixed to a casing 119. The first motor MG1 works as
a motor for rotating the rotor 132 through the interaction between
a magnetic field produced by the permanent magnets 135 and a
magnetic field produced by the three-phase coils 134, or as a
generator for generating an electromotive force on either ends of
the three-phase coils 134 through the interaction between the
magnetic field produced by the permanent magnets 135 and the
rotation of the rotor 132. The sun gear shaft 125 is further
provided with a resolver 139 for measuring its rotational angle
.theta.s.
Like the first motor MG1, the second motor MG2 is also constructed
as a synchronous motor-generator and includes a rotor 142 having a
plurality of permanent magnets 145 on its outer surface and a
stator 143 having three-phase coils 144 wound thereon to form a
revolving magnetic field. The rotor 142 is linked with the ring
gear shaft 126 connecting with the ring gear 122 of the planetary
gear 120, whereas the stator 14 is fixed to the casing 119. The
stator 143 of the motor MG2 is also produced by laying thin plates
of non-directional electromagnetic steel one upon another. Like the
first motor MG1, the second motor MG2 also works as a motor or a
generator. The ring gear shaft 126 is further provided with a
resolver 149 for measuring its rotational angle .theta.r.
The controller 180 for driving and controlling the first and the
second motor MG1 and MG2 has the following configuration. Referring
back to FIG. 1, the controller 180 includes a first driving circuit
191 for driving the first motor MG1, a second driving circuit 192
for driving the second motor MG2, a control CPU 190 for controlling
both the first and the second driving circuits 191 and 192, and a
battery 194 including a number of secondary cells. The control CPU
190 is a one-chip microprocessor including a RAM 190a used as a
working memory, a ROM 190b in which various control programs are
stored, an input/output port (not shown), and a serial
communication port (not shown) through which data are sent to and
received from the EFIECU 170. The control CPU 190 receives a
variety of data via the input port. The input data include a
rotational angle .theta.s of the sun gear shaft 125 measured with
the resolver 139, a rotational angle .theta.r of the ring gear
shaft 126 measured with the resolver 149, an accelerator pedal
position AP (step-on amount of the accelerator pedal 164) output
from the accelerator position sensor 164a, a brake pedal position
BP (step-on amount of the brake pedal 165) output from the brake
pedal position sensor 165a, a gearshift position SP output from the
gearshift position sensor 184, values of currents Iu1 and Iv1 from
two ammeters 195 and 196 disposed in the first driving circuit 191,
values of currents Iu2 and Iv2 from two ammeters 197 and 198
disposed in the second driving circuit 192, and a remaining charge
BRM of the battery 194 measured with a remaining charge meter 199.
The remaining charge meter 199 may determine the remaining charge
BRM of the battery 194 by any known method; for example, by
measuring the specific gravity of an electrolytic solution in the
battery 194 or the whole weight of the battery 194, by computing
the currents and time of charge and discharge, or by causing an
instantaneous short circuit between terminals of the battery 194
and measuring an internal resistance against the electric
current.
The control CPU 190 outputs a first control signal SW1 for driving
six transistors Tr1 through Tr6 working as switching elements of
the first driving circuit 191 and a second control signal SW2 for
driving six transistors Tr11 through Tr16 working as switching
elements of the second driving circuit 192. The six transistors Tr1
through Tr6 in the first driving circuit 191 constitute a
transistor inverter and are arranged in pairs to work as a source
and a drain with respect to a pair of power lines L1 and L2. The
three-phase coils (U,V,W) 134 of the first motor MG1 are connected
to the respective contacts of the paired transistors in the first
driving circuit 191. The power lines L1 and L2 are respectively
connected to plus and minus terminals of the battery 194. The
control signal SW1 output from the control CPU 190 thus
successively controls the power-on time of the paired transistors
Tr1 through Tr6. The electric currents flowing through the
three-phase coils 134 undergo PWM (pulse width modulation) control
to give quasi-sine waves, which enable the three-phase coils 134 to
form a revolving magnetic field.
The six transistors Tr1 through Tr16 in the second driving circuit
192 also constitute a transistor inverter and are arranged in the
same manner as the transistors Tr1 through Tr6 in the first driving
circuit 191. The three-phase coils (U,V,W) 144 of the second motor
MG2 are connected to the respective contacts of the paired
transistors in the second driving circuit 191. The second control
signal SW2 output from the control CPU 190 thus successively
controls the power-on time of the paired transistors Tr11 through
Tr16. The electric currents flowing through the three-phase coils
144 undergo PWM control to give quasi-sine waves, which enable the
three-phase coils 144 to form a revolving magnetic field.
The power output apparatus 110 of the embodiment thus constructed
works in accordance with the operation principles discussed below,
especially with the principle of torque conversion. By way of
example, it is assumed that the engine 150 is driven at a driving
point P1 of the revolving speed Ne and the torque Te and that the
ring gear shaft 126 is driven at another driving point P2, which is
defined by another revolving speed Nr and another torque Tr but
gives an amount of energy identical with an energy Pe output from
the engine 150. This means that the power output from the engine
150 is subjected to the torque conversion and applied to the ring
gear shaft 126. The relationship between the torque and the
revolving speed of the engine 150 and the ring gear shaft 126 under
such conditions is shown in the graph of FIG. 4.
According to the mechanics, the relationship between the revolving
speed and the torque of the three shafts in the planetary gear 120
(that is, the sun gear shaft 125, the ring gear shaft 126, and the
planetary carrier 124 (crankshaft 156)) can be expressed as
nomograms illustrated in FIGS. 5 and 6 and solved geometrically.
The relationship between the revolving speed and the torque of the
three shafts in the planetary gear 120 may be analyzed numerically
through calculation of energies of the respective shafts, without
using the nomograms. For the clarity of explanation, the nomograms
are used in this embodiment.
In the nomogram of FIG. 5, the revolving speed of the three shafts
is plotted as ordinate and the positional ratio of the coordinate
axes of the three shafts as abscissa. When a coordinate axis S of
the sun gear shaft 125 and a coordinate axis R of the ring gear
shaft 126 are positioned on either ends of a line segment, a
coordinate axis C of the planetary carrier 124 is given as an
interior division of the axes S and R at the ratio of 1 to .rho.,
where .rho. represents a ratio of the number of teeth of the sun
gear 121 to the number of teeth of the ring gear 122 and expressed
as Equation (1) given below: .rho..times. .times..times.
.times..times. .times..times. .times..times. .times..times.
.times..times. .times..times. .times..times. .times..times.
.times..times. .times..times. .times..times. .times..times. .times.
##EQU00001##
As mentioned above, the engine 150 is driven at the revolving speed
Ne, while the ring gear shaft 126 is driven at the revolving speed
Nr. The revolving speed Ne of the engine 150 can thus be plotted on
the coordinate axis C of the planetary carrier 124 linked with the
crankshaft 156 of the engine 150, and the revolving speed Nr of the
ring gear shaft 126 on the coordinate axis R of the ring gear shaft
126. A straight line passing through both the points is drawn, and
a revolving speed Ns of the sun gear shaft 125 is then given as the
intersection of this straight line and the coordinate axis S. This
straight line is hereinafter referred to as a dynamic collinear
line. The revolving speed Ns of the sun gear shaft 125 can be
calculated from the revolving speed Ne of the engine 150 and the
revolving speed Nr of the ring gear shaft 126 according to a
proportional expression given as Equation (2) below. In the
planetary gear 120, the determination of the rotations of the two
gears among the sun gear 121, the ring gear 122, and the planetary
carrier 124 results in automatically setting the rotation of the
residual one gear. .times. .times..rho..rho. ##EQU00002##
The torque Te of the engine 150 is then applied (upward in the
drawing) to the dynamic collinear line on the coordinate axis C of
the planetary carrier 124 functioning as a line of action. The
dynamic collinear line against the torque can be regarded as a
rigid body to which a force is applied as a vector. Based on the
technique of dividing the force into two different parallel lines
of action, the torque Te acting on the coordinate axis C is divided
into a torque Tes on the coordinate axis S and a torque Ter on the
coordinate axis R. The magnitudes of the torques Tes and Ter are
given by Equations (3) and (4) below: .times.
.times..rho..rho..times. .times..rho..rho. ##EQU00003##
The equilibrium of forces on the dynamic collinear line is
essential for the stable state of the dynamic collinear line. In
accordance with a concrete procedure, a torque Tm1 having the same
magnitude as but the opposite direction to the torque Tes is
applied to the coordinate axis S, whereas a torque Tm2 having the
same magnitude as but the opposite direction to a resultant force
of the torque Ter and the torque that has the same magnitude as but
the opposite direction to the torque Tr output to the ring gear
shaft 126 is applied to the coordinate axis R. The torque Tm1 is
given by the first motor MG1, and the torque Tm2 by the second
motor MG2. The first motor MG1 applies the torque Tm1 in reverse of
its rotation and thereby works as a generator to regenerate an
electrical energy Pm1, which is given as the product of the torque
Tm1 and the revolving speed Ns, from the sun gear shaft 125. The
second motor MG2 applies the torque Tm2 in the direction of its
rotation and thereby works as a motor to output an electrical
energy Pm2, which is given as the product of the torque Tm2 and the
revolving speed Nr, as a power to the ring gear shaft 126.
In case that the electrical energy Pm1 is identical with the
electrical energy Pm2, all the electric power consumed by the
second motor MG2 can be regenerated and supplied by the first motor
MG1. In order to attain such a state, all the input energy should
be output; that is, the energy Pe output from the engine 150 should
be equal to an energy Pr output to the ring gear shaft 126. Namely
the energy Pe expressed as the product of the torque Te and the
revolving speed Ne is made equal to the energy Pr expressed as the
product of the torque Tr and the revolving speed Nr. Referring to
FIG. 4, the power that is expressed as the product of the torque Te
and the revolving speed Ne and output from the engine 150 driven at
the driving point P1 is subjected to the torque conversion and
output to the ring gear shaft 126 as the power of the same energy
but expressed as the product of the torque Tr and the revolving
speed Nr. As discussed previously, the power output to the ring
gear shaft 126 is transmitted to a drive shaft 112 via the power
feed gear 128 and the power transmission gear 111, and further
transmitted to the driving wheels 116 and 118 via the differential
gear 114. A linear relationship is accordingly held between the
power output to the ring gear shaft 126 and the power transmitted
to the driving wheels 116 and 118. The power transmitted to the
driving wheels 116 and 118 can thus be controlled by adjusting the
power output to the right gear shaft 126.
Although the revolving speed Ns of the sun gear shaft 125 is
positive in the nomogram of FIG. 5, it may be negative according to
the revolving speed Ne of the engine 150 and the revolving speed Nr
of the ring gear shaft 126 as shown in the nomogram of FIG. 6. In
the latter case, the first motor MG1 applies the torque in the
direction of its rotation and thereby works as a motor to consume
the electrical energy Pm1 given as the product of the torque Tm1
and the revolving speed Ns. The second motor MG2, on the other
hand, applies the torque in reverse of its rotation and thereby
works as a generator to regenerate the electrical energy Pm2, which
is given as the product of the torque Tm2 and the revolving speed
Nr, from the ring gear shaft 126. In case that the electrical
energy Pm1 consumed by the first motor MG1 is made equal to the
electrical energy Pm2 regenerated by the second motor MG2 under
such conditions, all the electric power consumed by the first motor
MG1 can be supplied by the second motor MG2.
The above description refers to the fundamental torque conversion
in the power output apparatus 110 of the embodiment. The power
output apparatus 110 can, however, perform other operations as well
as the above fundamental operation that carries out the torque
conversion for all the power output from the engine 150 and outputs
the converted torque to the ring gear shaft 126. The possible
operations include an operation of charging the battery 194 with
the surplus electrical energy and an operation of supplementing an
insufficient electrical energy with the electric power stored in
the battery 194. These operations are implemented by regulating the
power output from the engine 150 (that is, the product of the
torque Te and the revolving speed Ne), the electrical energy Pm1
regenerated or consumed by the first motor MG1, and the electrical
energy Pm2 regenerated or consumed by the second motor MG2.
The operation principle discussed above is on the assumption that
the efficiency of power conversion by the planetary gear 120, the
motors MG1 and MG2, and the transistors Tr1 through Tr16 is equal
to the value `1`, which represents 100%. In the actual state,
however, the conversion efficiency is less than the value `1`, and
it is required to make the energy Pe output from the engine 150 a
little greater than the energy Pr output to the ring gear shaft 126
or alternatively to make the energy Pr output to the ring gear
shaft 126 a little smaller than the energy Pe output from the
engine 150. By way of example, the energy Pe output from the engine
150 may be calculated by multiplying the energy Pr output to the
ring gear shaft 126 by the reciprocal of the conversion efficiency.
In the state of the nomogram of FIG. 5, the torque Tm2 of the
second motor MG2 may be calculated by multiplying the electric
power regenerated by the first motor MG1 by the efficiencies of
both the motors MG1 and MG2. In the state of the nomogram of FIG.
6, on the other hand, the torque Tm2 of the second motor MG2 may be
calculated by dividing the electric power consumed by the first
motor MG1 by the efficiencies of both the motors MG1 and MG2. In
the planetary gear 120, there is an energy loss or heat loss due to
a mechanical friction or the like, though the amount of energy loss
is significantly small, compared with the whole amount of energy
concerned. The efficiency of the synchronous motors used as the
first and the second motors MG1 and MG2 is very close to the value
of `1`. Known devices such as GTOs applicable to the transistors
Tr1 through Tr16 have extremely small ON-resistance. The efficiency
of power conversion is thus practically equal to the value `1`. For
the matter of convenience, in the following discussion of the
embodiment, the efficiency is considered equal to the value `1`
(=100%), unless otherwise specified.
The following describes braking control of the vehicle which is
driven by the power output from the engine 150 to the ring gear
shaft 126 through the above torque conversion. There are three
different types of braking control; that is, braking control by the
first motor MG1 and the engine 150, braking control by the second
motor MG2, and braking control by the first motor MG1, the second
motor MG2, and the engine 150. In the braking control procedure by
the second motor MG2 functioning as a generator, the rotational
energy (kinetic energy) of the ring gear shaft 126, to which the
rotation of the driving wheel 116 is linearly transmitted, is taken
out as electrical energy and stored into the battery 194. The
braking control by the second motor MG2 is a known procedure and is
thus not specifically described here. The following describes first
the braking control procedure by the first motor MG1 and the engine
150 and then the braking control procedure by the first motor MG1,
the second moor MG2, and the engine 150. The braking control by the
first motor MG1, the second motor MG2, and the engine 150 is a
combination of the braking control by the first motor MG1 and the
engine 150 discussed below with the conventional braking control by
the second motor MG2.
In the braking control procedure by the first motor MG1 and the
engine 150, the first motor MG1 motors the engine 150 via the
planetary gear 120 while the fuel injection into the engine 150
stops. The energy required for friction and compression of the
piston in the engine 150 that is being motored is subjected to a
torque conversion and applied as a braking force to the ring gear
shaft 126.
In the power output apparatus 110 of the embodiment kept in the
shaft of the nomograms of FIGS. 5 and 6, it is assumed that both
the torque Tm1 of the first motor MG1 and the torque Tm2 of the
second motor MG2 are set equal to zero and that the operation of
the engine 150 (fuel injection) is stopped. Under such conditions,
the dynamic collinear line is stably kept in the state having the
least sum of the energy required for racing the engine 150 and the
energy required for racing the first motor MG1. Since the engine
150 is a four-cycle gasoline engine in the power output apparatus
110 of the embodiment, the energy required for racing the engine
150, that is, the energy required for friction and compression of
the piston in the engine 150, is greater than the energy required
for racing the rotor 132 of the first motor MG1. The dynamic
collinear line is accordingly in the state of stopping the engine
150 and racing the first motor MG1 as shown in the nomogram of FIG.
7.
In case that the first motor MG1 is driven and controlled in this
state to motor the engine 150 at a revolving speed NE1, the dynamic
collinear line falls into the state shown in the nomogram of FIG.
8, Te1 denotes a torque output from the engine 150 as a reaction
while the engine 150 is being motored at the revolving speed Ne1. A
divisional torque Ter1 calculated from the torque Te1 according to
Equation (4) is applied to the ring gear shaft 126 as discussed
previously. The torque Te1 working as the reaction has a direction
opposite to that of the torque Te output from the engine 150 while
the engine 150 is being driven as shown in the nomograms of FIGS. 5
and 6. The divisional torque Ter1 acting on the ring shaft 126 thus
functions as a braking force. In the state of the nomogram of FIG.
8, the direction of rotation of the sun gear shaft 125 is different
from the direction of the torque Tm1 of the first motor MG1. The
first motor MG1 accordingly functions as a generator and enables
part of the rotational energy (kinetic energy) of the sun gear
shaft 125 to be taken out as electrical energy, with which the
battery 194 is charged. The torque Tm1 output from the first motor
MG1 is calculated from the torque Te1 output from the engine 150
according to Equation (3) given above.
The first motor MG1 may be driven and controlled in the state of
the nomogram of FIG. 7 to motor the engine 150 at a revolving speed
Ne2 as shown in the nomogram of FIG. 9. Tc2 denotes a torque
working as a reaction while the engine 150 is being motored at the
revolving speed Ne2. In the same manner as the nomogram of FIG. 8,
a divisional torque Ter2 calculated from the torque Te2 according
to Equation (4) is applied to the ring gear shaft 126 as a braking
force. In the state of the nomogram of FIG. 9, the direction of
rotation of the sun gear shaft 125 is identical with the direction
of the torque Tm1 of the first motor MG1, and the motor MG1
accordingly functions as a motor. The electrical energy required
for the operation of the first motor MG1 is supplied by the
electric power discharged from the battery 194.
The relationship between the revolving speed Ne and the torque Te
working as a reaction while the engine 150 is being motored,
depends upon the type and characteristics of the engine 150. In
this embodiment, this relationship is determined experimentally and
stored in advance as a map in the ROM 190b. FIG. 10 shows one
example of this map. The torque Te output as a reaction from the
engine 150 depends upon the revolving speed Ne. The dynamic
collinear line thus falls into the state of the nomogram of FIG. 8
or into the state of the nomogram of FIG. 9 according to the
magnitude of the braking force applied to the ring gear shaft 126
and the revolving speed Nr of the ring gear shaft 126. The
procedure of adequately specifying the magnitude of the braking
force output to the ring gear shaft 126 by taking into account the
revolving speed Nr of the ring gear shaft 126 enables the first
motor MG1 to carry out either the regenerative operation or the
power operation and thereby allows the battery 194 to be charged or
discharged.
A fundamental braking control by the first motor MG1 and the engine
150 follows a braking control routine shown in the flowchart of
FIG. 11. The braking control routine is executed repeatedly when
the driver steps on the brake pedal 165 and a braking torque Tr*
used in the process of braking control by the first motor MG1 and
the engine 150 is set based on the step-on amount of the brake
pedal 165. When this braking control routine is carried out, the
control CPU 190 of the controller 180 concurrently outputs a stop
signal to the EFIECU 170 through communications so as to stop the
fuel injection into the engine 150.
When the program enters the routine of FIG. 11, the control CPU 190
of the controller 180 first reads the braking torque Tr* at step
S100. The braking torque Tr* is set according to the step-on amount
of the brake pedal 165 and written at a predetermined address in
the RAM 190a. In accordance with a concrete procedure, the control
CPU 190 reads the data of braking torque Tr* previously written at
the redetermined address at step S100. The control CPU 190 then
sets a target revolving speed Ne* of the engine 150 based on the
braking torque Tr* at step S102. In order to output the braking
torque Tr* to the ring gear shaft 126, the engine 150 is required
to output the torque Te, which is obtained by substituting the
value Tr* for the torque Ter in Equation (4) rewritten with respect
to Te. In accordance with a concrete procedure, the revolving speed
Ne corresponding to the torque Te thus obtained is read from the
map shown in FIG. 10 and set as the target revolving speed Ne* at
step S102.
After setting the target revolving speed Ne* of the engine 150, the
control CPU 190 reads the revolving speed Nr of the ring gear shaft
126 and the revolving speed Ns of the sun gear shaft 125 at step
S104. The revolving speed Ns of the sun gear shaft 125 may be
calculated from the rotational angle .theta.s of the sun gear shaft
125 read from the resolver 139, where as the revolving speed Nr of
the ring gear shaft 126 may be calculated from the rotational angle
.theta.r of the ring gear shaft 126 read from the resolver 149. The
control CPU 190 subsequently calculates a target revolving speed
Ns* of the sun gear shaft 125 from the target revolving speed Ne*
of the engine 150 and the revolving speed Nr of the ring gear shaft
Nr according to Equation (5) given below at step S106. Equation (5)
is obtained by substituting the target revolving speed Ne* of the
engine 150 for Ne in Equation (2). .rarw..times..rho..rho.
##EQU00004##
The control CPU 190 calculates and sets a torque command value Tm1*
of the first motor MG1 according to Equation (6) given below at
step S108. The first term on the right side of Equation (6) is
obtained from the equilibrium on the dynamic collinear line shown
in the nomogram of FIG. 8 or FIG. 9. The second term on the right
side is a proportional term to cancel the deviation of the actual
revolving speed Ns from the target revolving speed Ns*, and the
third term on the right side is an integral term to cancel the
stationary deviation. In the stationary state (that is, when the
deviation of the revolving speed Ns from the target revolving speed
Ns* is equal to zero), the torque command value Tm1* of the first
motor MG1 is set equal to the first term on the right side
Tr*x.rho. obtained from the equilibrium on the dynamic collinear
line. K1 and K2 in Equation (6) denote proportional constants.
Tm1*.rarw.Tr*x.rho.+K1(Ns*-Ns)+K2.intg.(Ns*-Ns)dt (6)
After setting the torque command value Tm1* of the first motor MG1,
the control CPU 190 receives the rotational angle .theta.s of the
sun gear shaft 125 from the revolver 139 at step S110 and
calculates an electrical angle .theta.1 of the first motor MG1 from
the rotational angle .theta.s of the sun gear shaft 125 at step
S111. In this embodiment, since a synchronous motor of the
four-pole pair (that is, four N poles and four S poles) is used as
the first motor MG1, the rotational angle .theta.s of the sun gear
shaft 125 is quadrupled to yield the electrical angle .theta.1
(.theta.1=4.theta.s). The control CPU 190 then detects values of
currents Iu1 and Iv1 flowing through the U phase and V phase of the
three-phase coils 134 in the first motor MG1 with the ammeters 195
and 196 at step S112. Although the currents naturally flow through
all the three phases U, V, and W, measurement is required only for
the currents passing through the two phases since the sum of the
currents is equal to zero. At subsequent step S114, the control CPU
190 executes transformation of coordinates (three-phase to
two-phase transformation) using the values of currents flowing
through the three phases obtained at step 112. The transformation
of coordinates maps the values of currents flowing through the
three phases to the values of currents passing through d and q axes
of the permanent magnet-type synchronous motor and is executed
according to Equation (7) given below. The transformation of
coordinates is carried out because the currents flowing through the
d and q axes are essential for the torque control in the permanent
magnet-type synchronous motor. Alternatively, the torque control
may be executed directly with the currents flowing through the
three phases. .function..times. .times..theta..times.
.times..times. .times..theta..times. .times..times.
.times..theta..times. .times..times. .times..theta..times.
.times..function. ##EQU00005##
After the transformation to the currents of two axes, the control
CPU 190 computes deviations of currents Id1 and Iq1 actually
flowing through the d and q axes from current command values Id1*
and Iq1* of the respective axes, which are calculated from the
torque command value Tm1* of the first motor MG1, and subsequently
determines voltage command values Vd1 and Vq1 with respect to the d
and q axes at step S116. In accordance with a concrete procedure,
the control CPU 190 executes arithmetic operations of Equations (8)
and Equations (9) given below. In Equations (9), Kp1, Kp2, Ki1, and
Ki2 represent coefficients, which are adjusted to be suited to the
characteristics of the motor applied. Each voltage command value
Vd1 (Vq1) includes a part in proportion to the deviation .DELTA.I
from the current command value I* (the first term on the right side
of Equation (9)) and a summation of historical data of the
deviations .DELTA.I for `i` times (the second term on the right
side). .DELTA.Id1=Id1*-Id1 .DELTA.Iq1=Iq1*-Iq1 (8)
Vd1=Kp1.DELTA.Id1+.SIGMA.Ki1.DELTA.Id1
Vq1=Kp2.DELTA.Iq1+.SIGMA.Ki2.DELTA.Iq1 (9)
The control CPU 190 then re-transforms the coordinates of the
voltage command values thus obtained (two-phase to three-phase
transformation) at step S118. This corresponds to an inverse of the
transformation executed at step S114. The inverse transformation
determines voltages Vu1, Vv1, and Vw1 actually applied to the
three-phase coils 134 as expressed by Equations (10) given below:
.function..times. .times..theta..times. .times..times.
.times..theta..times. .times..times. .times..theta..times.
.times..times. .times..theta..times.
.times..function..times..times. ##EQU00006##
The actual voltage control is accomplished by on-off operation of
the transistors Tr1 through Tr6 in the first driving circuit 191.
At step S119, the on- and off-time of the transistors Tr1 through
Tr6 in the first driving circuit 191 is PWM (pulse with modulation)
controlled, in order to attain the voltage command values Vu1, Vv1,
and Vw1 determined by Equations (10) given above.
It is assumed that the torque command value Tm1* of the first motor
MG1 is positive when the torque Tm1 is applied in the direction
shown in the nomograms of FIGS. 8 and 9. For an identical positive
torque command value Tm1*, the first motor MG1 is controlled to
carry out the regenerative operation when the torque command value
Tm1* acts in reverse of the rotation of the sun gear shaft 125 as
in the state of the nomogram of FIG. 8, and controlled to carry out
the power operation when the torque command value Tm1* acts in the
direction of rotation of the sun gear shaft 125 as in the state of
the nomogram of FIG. 9. For the positive torque command value Tm1*,
both the regenerative operation and the power operation of the
first motor MG1 implement the identical switching control. In
accordance with a concrete procedure, the transistors Tr1 through
Tr6 in the first driving circuit 191 are controlled to enable a
possible torque to be applied to the sun gear shaft 125 by the
combination of the magnetic field generated by the permanent
magnets 135 set on the outer surface of the rotor 132 with the
revolving magnetic field generated by the currents flowing through
the three-phase coils 134. The identical switching control is
executed for both the regenerative operation and the power
operation of the first motor MG1 as long as the sign of the torque
command value Tm1* is not changed. The braking control routine
shown in the flowchart of FIG. 11 is thus applicable to both the
regenerative operation and the power operation.
The above and control procedure sets the dynamic collinear line
either in the state of the nomogram of FIG. 8 or in the state of
the nomogram of FIG. 9 and enables the braking force to be applied
to the ring gear shaft 126 and eventually to the driving wheels 116
and 118.
As discussed above, the power output apparatus 110 of the
embodiment carries out the braking control by the first motor MG1
and the engine 150 and enables the braking force to be applied to
the ring gear shaft 126 and eventually to the driving wheels 116
and 118. The procedure of adequately specifying the magnitude of
the braking torque Tr* output to the ring gear shaft 126 by taking
into account the revolving speed Nr of the ring gear shaft 126
enables the first motor MG1 to carry out the regenerative operation
for braking and charge the battery 194 or enables the first motor
MG1 to carry out the power operation for braking and discharge the
battery 194. Namely the first motor MG1 can implement braking by
the regenerative operation or by the power operation according to
the remaining charge BRM of the battery 194.
In the braking control routine of the embodiment, the torque
command value Tm1* of the first motor MG1 and the target revolving
speed Ns* of the sun gear shaft 125 are set to enable the preset
braking torque Tr* to be output to the ring gear shaft 126 by means
of the first motor MG1 and the engine 150. In accordance with
another possible application, the braking torque Tr* may be set
based on the remaining charge BRM of the battery 194. This
structure keeps the remaining charge BRM of the battery 194 at a
desired level.
Although the fuel injection into the engine 150 is stopped in the
embodiment, the fuel injection may be carried out to rotate the
engine 150 at an idle revolving speed or another adequate revolving
speed. The torque Te working as a reaction in the latter case is
different from that in the case of the embodiment. The relationship
between the amount of fuel injection, the revolving speed Ne, and
the torque Te working as a reaction should thus be determined in
advance and stored as a map.
The braking control procedure of the embodiment positively controls
the first motor MG1, in order to enable the braking torque Tr* to
be applied to the ring gear shaft 126 as a braking force. An
alternative braking control procedure electromagnetically fixes the
rotor 132 of the first motor MG1, that is, locks up the first motor
MG1, in order to enable the braking force to be applied to the ring
gear shaft 126. FIG. 12 is a nomogram in this state. While the sun
gear shaft 125 is fixed, the planetary gear 120 works as a
reduction gear. The rotation of the ring gear shaft 126 multiplied
by a reduction ratio is accordingly transmitted as the rotation of
the crankshaft 156. This is equivalent to the operation of engine
brake. The control operation of the first motor MG1 in this case
turns off all the transistors Tr1 through Tr6 in the first driving
circuit 191 for driving the first motor MG1.
The following describes the braking control procedure by the first
motor MG1, the second motor MG2, and the engine 150. As mentioned
previously, the braking control by the first motor MG1, the second
motor MG2, and the engine 150 is a combination of the braking
control by the first motor MG1 and the engine 150 with the braking
control by the second motor MG2. This braking control includes a
variety of operations: for example, the operation of applying a
braking force corresponding to the step-on amount of the brake
pedal 165 to the ring gear shaft 126 and the operation of applying
a braking force to the ring gear shaft 126 irrespective of the
step-on of the brake pedal 165 while the vehicle runs down a long,
continuous slope. In this embodiment, the operation of applying a
braking force corresponding to the step-on amount of the brake
pedal 165 to the ring gear shaft 126 follows a torque control
routine in a braking state shown in the flowcharts of FIGS. 13 and
14. The operation of applying a braking force to the ring gear
shaft 126 irrespective of the step-on of the brake pedal 165 while
the vehicle runs down a long, continuous slope, follows a
continuous braking control routine shown in the flowchart of FIG.
24.
The torque control routine in the braking state shown in the
flowcharts of FIGS. 13 and 14 is executed repeatedly at
predetermined time intervals (for example, at every 8 msec) while
the vehicle runs. When the program enters the routine of FIG. 13,
the control CPU 190 of the controller 180 first reads the brake
pedal position BP detected by the brake pedal position sensor 165a
at step S120. The driver steps on the brake pedal 165 to apply the
braking force to the driving wheels 116 and 118. The value of the
brake pedal position BP accordingly represents the desired braking
torque which the driver requires. The control CPU 190 subsequently
determines the braking torque Tr* to be output to the ring gear
shaft 126, based on the input brake pedal position BP at step S122.
Not the braking torque to be output to the driving wheels 116 and
118 but the braking torque Tr* to be output to the ring gear shaft
126 is determined here according to the brake pedal position BP.
This is because the ring gear shaft 126 is mechanically linked with
the driving wheels 116 and 118 via the power feed gear 128, the
power transmission gear 111, and the differential gear 114 and the
determination of the braking torque Tr* to be output to the ring
gear shaft 126 thus results in determining the braking torque to be
output to the driving wheels 116 and 118. In this embodiment, a map
representing the relationship between the braking torque Tr* and
the brake pedal position BP is prepared in advance and stored in
the ROM 190b. In accordance with a concrete procedure, at step
S122, the braking torque Tr* corresponding to the input brake pedal
position BP is read from the map stored in the ROM 190b.
The control CPU 190 then reads the remaining charge BRM of the
battery 194 measured by the remaining charge meter 199 at step
S124, and compares the input remaining charge BRM of the battery
194 with a threshold value Bref at step S126. The threshold value
Bref is set as a value close to the fully charged state in which
the battery 194 does not require any further charging, and depends
upon the type and characteristics of the battery 194. FIG. 15 is a
graph showing the relationship between the remaining charge BRM of
the battery 194 and the chargeable electric power with the
threshold value Bref.
In case that the remaining charge BRM of the battery 194 is less
than the threshold value Bref at step S126, the program determines
the necessity for charging the battery 194 and sets the torque
command value Tm1* of the first motor MG1 equal to the zero at step
S128 while setting the braking amount Tr* to a torque command value
Tm2* of the second motor MG2 at step S130. The control CPU 190 then
outputs a signal to stop the fuel injection into the engine 150
from the communication port to the EFIECU 170 at step S132. The
program subsequently controls the first motor MG1, the second motor
MG2, and the engine 150 based on the preset values at step S134
through S138. As a matter of convenience of illustration, the
control operations of the first motor MG1, the second motor MG2,
and the engine 150 are shown as separate steps. In the actual
procedure, however, these control operations are carried out in
parallel and comprehensively. By way of example, the control CPU
190 simultaneously controls the first motor MG1 and the second
motor MG2 by utilizing an interrupting process, while transmitting
an instruction to the EFIECU 170 through communication in order to
allow the EFIECU 170 to control the engine 150 concurrently.
The control of the first motor MG1 follows a control routine of the
first motor MG1 shown in the flowchart of FIG. 16, whereas the
control of the second motor MG2 follows a control routine of the
second motor MG2 shown in the flowchart of FIG. 17. These control
routines are identical with the processing steps S110 through S119
in the braking control routine of FIG. 11 and are not specifically
described here. When the torque command value Tm1* of the first
motor MG1 is set equal to zero, the control of the first motor MG1
does not follow the control routine of the first motor MG1 shown in
the flowchart of FIG. 16 but turns off all the transistors Tr1
through Tr6 in the first driving circuit 191, as discussed
previously. The control of the engine 150 is carried out by the
EFIECU 170 which receives the instruction to stop the fuel
injection. The EFIECU 170 actually stops the fuel injection as well
as the ignition with the ignition plug 162, thereby stopping the
operation of the engine 150.
When the remaining charge BRM of the battery 194 is determined to
be less than the threshold value Bref at step S126, the operation
of setting both the torque Tm1 of the first motor MG1 and the
torque Tm2 of the second motor MG2 equal to zero and stopping the
operation of the engine 150 (fuel injection) discussed above with
the nomogram of FIG. 7 is combined with the operation of enabling
the second motor MG2 to apply a torque corresponding to the torque
command value Tm2* to the ring gear shaft 126. As shown in the
nomogram of FIG. 18, this procedure stops the engine 150 and races
the first motor MG1. As discussed previously, this state consumes
the least energy, so that a greater portion of the rotational
energy (kinetic energy) of the ring gear shaft 126 can be
regenerated as electrical energy by the second motor MG2 and stored
in the battery 194.
In case that the remaining charge BRM of the battery 194 is not
less than the threshold value Bref at step S126, on the other hand,
the program determines no necessity for charging the battery 194
and carries out the processing of steps S140 through S152 shown in
the flowchart of FIG. 14. This processing sets the torque command
value Tm1* of the first motor MG1 and the torque command value Tm2*
of the second motor MG2, in order to enable a braking force to be
applied to the ring gear shaft 126 while not charging the battery
194. In the routine of FIG. 14, the control CPU 190 of the
controller 180 first reads the revolving speed Nr of the ring gear
shaft 126 and the revolving speed Ns of the sun gear shaft 125 at
step S140, and calculates a braking energy Pr required for braking
by Pr=Tr*.times.Nr at step S142.
The control CPU 190 then sets the target torque Te* and the target
revolving speed Ne* of the engine 150 based on the calculated
braking energy Pr at step S144. The energy consumed by the engine
150 is identical with the product of the torque Te working as a
reaction force and the revolving speed Ne of the engine 150. The
braking energy Pr and the target torque Tr* and the target
revolving speed Ne* of the engine 150 accordingly satisfy the
relationship of Pr=Te*.times.Ne*. As discussed previously with the
graph of FIG. 10, the relationship between the revolving speed Ne
of the engine 150 and the torque Te working as a reaction force is
determined unequivocally. The required operation accordingly fields
a specific point at which the product becomes equal to the braking
energy Pr and specifies the torque Te and the revolving speed Ne at
the specific point as the target torque Te* and the target
revolving speed Ne* of the engine 150. By way of example, the
specific point can be obtained as an intersection of a curve A
representing the relationship between the revolving speed Ne of the
engine 150 and the torque Te working as a reaction force and a
constant energy curve Pr as shown in the graph of FIG. 19. In this
embodiment, the braking energy Pr and the corresponding revolving
speed Ne and torque Te of the engine 150 are stored in the form of
a map in the ROM 190b. In accordance with a concrete procedure, at
step S144, the revolving speed Ne and the torque Te corresponding
to the calculated braking energy Pr are read from the map stored in
the ROM 190b and set as the target engine speed Ne* and the target
engine torque Te*.
The control CPU 190 then calculates the target revolving speed Ns*
of the sun gear shaft 125 according to Equation (5) given above at
step S146, and calculates and sets the torque command value Tm1* of
the first motor MG1 according to Equation (11) given below at step
S148. Equation (11) is similar to Equation (6), except that the
first term on the right side depends upon the target torque Te* of
the engine 150. .rarw..times..rho..rho..times. .times..times.
.times..intg..times.d ##EQU00007##
After setting the torque command value Tm1* of the first motor MG1,
the control CPU 190 calculates an electrical energy Pm1 consumed or
regenerated by the first motor MG1 according to Equation (12) given
below at step S150, and calculates and sets the torque command
value Tm2* of the second motor MG2 from the calculated electrical
energy Pm1 according to Equation (13) given below at step S152. Km1
and Km2 denote motor efficiencies of the first motor MG1 and the
second motor MG2. .rarw..times..times..rarw..times.
##EQU00008##
The program then returns to step S132 in the flowchart of FIG. 13
to output a signal for stopping the fuel injection into the engine
150 from the communication port to the EFIECU 170 at step S132, and
controls the first motor MG1, the second motor MG2, and the engine
150 based on the preset values at steps S134 through S138.
As an example of such control, the nomogram of FIG. 20 sows the
state when the first motor MG1 is controlled to carry out the power
operation. Referring to FIG. 20, the ring gear shaft 126 receives
the braking torque Tr* as the sum of the divisional torque Ter
based on the torque Te working as a reaction and the torque Tm2
corresponding to the torque command value Tm2* output from the
second motor MG2. Although not specifically illustrated, the
dynamic collinear line falls into the state shown in the nomogram
of FIG. 8 when the first motor MG1 is controlled to carry out the
regenerative operation. In case that the first motor MG1 carries
out the regenerative operation and the second motor MG2 carries out
the power operation, the torque output from the second motor MG2
has the direction opposite to the direction of the torque Tm2 shown
in FIG. 20.
When the remaining charge BRM of the battery 194 is not less than
the threshold value Bref at step S126 in the flowchart of FIG. 13,
the electrical energy Pm1 consumed or regenerated by the first
motor MG1 is regenerated or consumed by the second motor MG2. The
battery 194 is accordingly neither charged nor discharged. This
process enables a desired braking force to be output to the ring
gear shaft 126 while neither charging nor discharging the battery
194.
In the torque control routine in the braking state of the
embodiment, when the remaining charge BRM of the battery 194 is
less than the threshold value Bref at step S126, the program sets
the torque command value Tm1* of the first motor MG1 equal to zero,
thereby stopping the engine 150 and racing the first motor MG1. In
accordance with another possible application, however, the engine
150 may be driven at a desired revolving speed. By way of example,
in order to drive the engine 150 at a predetermined revolving speed
Nst, the processing of steps S128 and S130 in the torque control
routine in the braking state shown in the flowcharts of FIGS. 13
and 14 may be replaced with the processing of steps S180 through
S188 in a modified torque control routine in the braking state
shown in the flowchart of FIG. 21.
In the modified torque control routine in the braking state of FIG.
21, the control CPU 190 of the controller 180 sets the
predetermined revolving speed Nst to the target revolving speed Ne*
of the engine 150 at step S180, and reads a torque Tst working as a
reaction force and corresponding to the predetermined revolving
speed Nst from the map (for example, the map of FIG. 10) at step
S181. The control CPU 190 then reads the revolving speed Nr of the
ring gear shaft 126 at step S182 and calculates the target
revolving speed Ns* of the sun gear shaft 125 according to Equation
(5) given above at step S184. The control CPU 190 subsequently
calculates and sets the torque command value Tm1* of the first
motor MG1 according to Equation (14) given below at step S186, and
calculates and sets the torque command value Tm2* of the second
motor MG2 according to Equation (15) given below at step S188. The
program then carries out the processing of steps S132 through S138
in the flowchart of FIG. 13. The nomogram of FIG. 22 shows the
state when such control is carried out. The control of the first
motor MG1 enables the engine 150 to be driven at the predetermined
revolving speed Nst. .rarw..times..rho..rho..times. .times..times.
.times..intg..times.d.rarw..times..rho. ##EQU00009##
This modified procedure does not stop the operation of the engine
150 but allows the rotation of the engine 150 at the predetermined
revolving speed Nst. When the driver steps on the accelerator pedal
164 in the course of the braking control and requires the engine
150 to output the energy Pe corresponding to the step-on amount of
the accelerator pedal 164, this modified procedure more quickly
realizes the requirement than the procedure of the embodiment. The
predetermined revolving speed Nst set to the target revolving speed
Ne* of the engine 150 at step S180 may be varied with a variation
in revolving speed Nr of the ring gear shaft 126 as shown in the
graph of FIG. 23. This further enhances the speed of the procedure
of outputting the required energy from the engine 150.
As mentioned above, the operation of applying a braking force to
the ring gear 126 irrespective of the step-on of the brake pedal
165 while the vehicle runs down a long, continuous slope, follows a
continuous braking control routine shown in the flowchart of FIG.
24. This routine is executed when the driver sets a continuous
braking torque Tr2* and steps on neither the accelerator pedal 164
nor the brake pedal 165. The continuous braking torque Tr2* is set
through an operation of a switch disposed near the driver's seat.
In this embodiment, the continuous braking torque Tr2* can be
selected among three different stages.
When the program enters the routine of FIG. 24, the control CPU 190
of the controller 180 first reads the continuous braking torque
Tr2* at step S200. The continuous braking torque Tr2* is set
through the operation of the switch by the driver and written at a
predetermined address in the RAM 190a. In accordance with a
concrete procedure, the control CPU 190 reads the data of
continuous braking torque Tr2* previously written at the
predetermined address at step S200. The control CPU 190 then reads
the remaining charge BRM of the battery 194 detected by the
remaining charge meter 199 at step S202, and compares the input
remaining charge BRM with the threshold value Bref at step
S204.
In case that the remaining charge BRM of the battery 194 is not
less than the threshold value Bref at step S204, the program
determines no necessity for charging the battery 194 and carries
out the processing of steps S206 through S218 to set the torque
command value Tm1* of the first motor MG1 and the torque command
value Tm2* of the second motor MG2, so as to enable the continuous
braking torque Tr2* to be output to the ring gear shaft 126 while
neither charging nor discharging the battery 194. The processing of
steps S206 through S218 is identical with the processing of steps
S140 through S152 in the torque control routine in the braking
state shown in the flowcharts of FIGS. 13 and 14. The procedure of
setting the torque command value Tm1* of the first motor MG1 and
the torque command value Tm2* of the second motor MG2 in this
manner enables the continuous braking torque Tr2* to be output to
the ring gear shaft 126 while the battery 194 is kept intact, as
discussed previously with the routine of FIGS. 13 and 14.
In case that the remaining charge BRM of the battery 194 is less
than the threshold value Bref at step S204, on the other hand, the
program determines the necessity for charging the battery 194 and
sets the torque command value Tm1* of the first motor equal to zero
at step S220 while setting the continuous braking torque Tr2* to
the torque command value Tm2* of the second motor MG2 at step S222.
The processing of steps S220 and S222 is equivalent to the
processing of steps S128 and S130 in the torque control routine in
the braking state shown in the flowcharts of FIGS. 13 and 14. The
procedure of setting the torque command value Tm1* of the first
motor MG1 and the torque command value Tm2* of the second motor MG2
in this manner enables the continuous braking torque Tr2* to be
output to the ring gear shaft 126 while the battery 194 is charged,
as discussed previously with the routine of FIGS. 13 and 14.
After setting the torque command value Tm1* of the first motor MG1
and the torque command value Tm2* of the second motor MG2, the
program outputs a signal for stopping the fuel injection into the
engine 150 to the EFIECU 170 at step S224 and controls the first
motor MG1, the second motor MG2, and the engine 150 based on the
preset values at steps S226 through S230. The processing of steps
S226 through S230 is identical with the processing of steps S134
through S138 in the torque control routine in the braking state
shown in the flowcharts of FIGS. 13 and 14.
The continuous braking control routine allows the torque
corresponding to the preset continuous braking torque Tr2* to be
output to the ring gear shaft 126 even when the driver does not
step on the brake pedal 165. The vehicle can accordingly run down a
long, continuous slope without requiring the driver to continue
stepping on the brake pedal 165.
The continuous braking control routine is carried out while the
driver steps on neither the accelerator pedal 164 nor the brake
pedal 165. This accordingly does not interfere with the torque
control in an accelerating state based on the step-on amount of the
accelerator pedal 164 or with the torque control in a braking state
based on the step-on amount of the brake pedal 165.
This procedure can realize the braking control while the battery
194 is charged or while the battery 194 is kept intact, according
to the remaining charge BRM of the battery 194. This keeps the
remaining charge BRM of the battery 194 at the level of the
threshold value Bref.
Although the magnitude of the continuous braking torque Tr2* is
selected among the three different stages in this embodiment, it
may be selected among a greater number of stages or fixed to one
stage. In this embodiment, the driver sets the magnitude of the
continuous braking torque Tr2*. The continuous braking torque Tr2*
may, however, be set based on the revolving speed of the driving
wheels 116 and 118, that is, the revolving speed Nr of the ring
gear shaft 126, or the rate of change of the revolving speed Nr.
The latter structure allows a greater braking torque to be output
to the ring gear shaft 126 in case of the greater revolving speed
Nr of the ring gear shaft 126 (that is, when the vehicle runs at a
high speed) or in case of the greater rate of change of the
revolving speed Nr of the ring gear shaft 126 (that is, the greater
rate of change of the vehicle speed).
In the continuous braking control routine of the embodiment, the
braking control with the charge of the battery 194, which is
executed when the remaining charge BRM of the battery 194 is less
than the threshold value Bref, sets the torque command value Tm1*
of the first motor MG1 equal to zero and stops the operation of the
engine 150. As discussed with the modified routine of FIG. 21,
however, the revolving speed Ne of the engine 150 may be set equal
to the predetermined revolving speed Nst. This structure enables
the engine 150 to output the required energy quickly in response to
the step-on of the accelerator pedal 164.
In the continuous braking control routine of the embodiment, the
braking control without the charge of the battery 194, which is
executed when the remaining charge BRM of the battery 194 is not
less than the threshold value Bref, controls the first motor MG1
and the second motor MG2 to enable the electrical energy Pm1
regenerated or consumed by the first motor MG1 to be consumed or
regenerated by the second motor MG2, thereby allowing the
continuous braking torque Tr2* to be output to the ring gear shaft
126. In accordance with another possible application, the braking
force may be output to the ring gear shaft 126 while the first
motor MG1 is kept in the lock-up state as shown in the nomogram of
FIG. 12. In this case, although the preset continuous braking
torque Tr2* can not be output to the ring gear shaft 126, the
braking torque corresponding to the revolving speed Nr of the ring
gear shaft 126 can be output to the ring gear shaft 126.
As discussed above, the power output apparatus 110 of the
embodiment enables the braking torque Tr* or the continuous braking
torque Tr2* to be output to the ring gear shaft 126 by means of the
first motor MG1 and the engine 150 or by means of the first motor
MG1, the second motor MG2, and the engine 150. Another possible
structure outputs part of the engine 150. Another possible
structure outputs part of the braking torque Tr* or the continuous
braking torque Tr2* of the ring gear shaft 126 by means of a
mechanical friction brake while outputting the residual torque by
means of the first motor MG1, the second motor MG2, and the engine
150.
In the power output apparatus 110 of the embodiment, the power
output to the ring gear shaft 126 is taken out of the arrangement
between the first motor MG1 and the second motor MG2 via the power
feed gear 128 linked with the ring gear 122. Like another power
output apparatus 110A shown in FIG. 25 as a modified example,
however, the power may be taken out of the casing 119, from which
the ring gear shaft 126 is extended. FIG. 26 shows still another
power output apparatus 110B as another modified example, wherein
the engine 150, the planetary gear 120, the second motor MG2, and
the first motor MG1 are arranged in this sequence. In this case, a
sun gear shaft 125B may not have a hollow structure, whereas a
hollow ring gear shaft 126B is required. This modified structure
enables the power output to the ring gear shaft 126B to be taken
out of the arrangement between the engine 150 and the second motor
MG2.
The following describes another power output apparatus 110C as a
second embodiment according to the present invention. FIG. 27
schematically illustrates structure of an essential part of the
power output apparatus 110C of the second embodiment. Referring to
FIG. 27, the power output apparatus 110C of the second embodiment
has a similar structure to that of the power output apparatus 110
of the first embodiment, except that the rotor 142 of the second
motor MG2 is attached to the crankshaft 156 and that the first
motor MG1 and the second motor MG2 have a different configuration.
The same constitutes as those of the power output apparatus 110 of
the first embodiment shown in FIG. 1, such as the controller 180,
are omitted from the drawing of FIG. 27. The power output apparatus
110C of the second embodiment can also be mounted on the vehicle as
shown in the drawing of FIG. 3. The same constitutes in the power
output apparatus 110C of the second embodiment as those in the
power output apparatus 110 of the first embodiment are shown by
like numerals and symbols and not specifically described here. The
symbols used in the description of the first embodiment have the
same meanings in the description of the second embodiment, unless
otherwise specified.
In the power output apparatus 110C of the second embodiment, the
engine 150, the second motor MG2, the planetary gear 120, and the
first motor MG1 are arranged in this sequence as shown in FIG. 27.
The rotor 132 of the first motor MG1 is attached to a sun gear
shaft 125C, which connects with the sun gear 121 of the planetary
gear 120, whereas the planetary carrier 124 is linked with the
crankshaft 156 of the engine 150 like the power output apparatus
110 of the first embodiment. The rotor 142 of the second motor MG2
and a resolver 157 for measuring a rotational angle .theta.e of the
crankshaft 156 are further attached to the crankshaft 156. A ring
gear shaft 126C, which connects with the ring gear 122 of the
planetary gear 120, is linked with the power feed gear 128. A
resolver 149 for measuring a rotational angle .theta.r of the ring
gear shaft 126C is attached to the ring gear shaft 126C.
The power output apparatus 110C of the second embodiment has a
different configuration from that of the power output apparatus 110
of the first embodiment. Like the power output apparatus 110 of the
first embodiment, however, the three-phase coils 134 of the first
motor MG1 is connected to the first driving circuit 191 of the
controller 180, and the three-phase coils 144 of the second motor
MG2 to the second driving circuit 192. Although not specifically
illustrated, the resolver 157 is connected to the input port of the
control CPU 190 of the controller 180 through a signal line.
The power output apparatus 110C of the second embodiment works in
the following manner. By way of example, it is assumed that the
engine 150 is driven at a driving point P1 of the resolving speed
Ne and the torque Te and outputs an amount of energy Pe
(pe=Ne.times.Te) and that the ring gear shaft 126C is driven at
another driving point P2 of the revolving speed Nr and the torque
Tr and outputs an amount of energy Pr (Pr=Nr.times.Tr) identical
with the energy Pe. This means that the power output from the
engine 150 is subjected to the torque conversion and applied to the
ring gear shaft 126C. FIGS. 28 and 29 are nomograms in this
state.
Equations (16) through (19) given below are obtained from the
equilibrium on the dynamic collinear line in the nomogram of FIG.
28. Equation (16) is obtained from the equilibrium of the energy Pe
output form the engine 150 with the energy Pr output to the ring
gear shaft 126C, and Equation (17) as the total energy input to the
planetary carrier 124 via the crankshaft 156. Equations (18) and
(19) are led by dividing a torque Tc acting on the planetary
carrier 124 into divisional torques Tcs an Tcr acting on the
coordinate axes S and R. Te.times.Ne=Tr.times.Nr (16)
Tc=Te+Tm2 (17) .times..rho..rho..times..rho. ##EQU00010##
The equilibrium of forces on the dynamic collinear line is
essential for the stable state of the dynamic collinear line. It is
accordingly required to set the torque Tm1 equal to the divisional
torque Tcs and the torque Tr equal to the divisional torque Tcr.
The torques Tm1 and Tm2 are thus expressed by Equations (20) and
(21) given below: Tm1=Tr.times..rho. (20) Tm2=Tm(1+.rho.)-Tc
(21)
The power output from the engine 150 and defined by the torque Te
and the revolving speed Ne is converted to the power defined by the
torque Tr and the revolving speed Nr and output to the ring gear
shaft 126C by allowing the first motor MG1 to apply the torque Tm1
expressed by Equation (20) to the sun gear shaft 125C and allowing
the second motor MG2 to apply the torque Tm2 expressed by Equation
(21) to the crankshaft 156. In the state of the nomogram of FIG.
28, the direction of the torque output from the first motor MG1 is
opposite to the direction of the rotation of the rotor 132. The
first motor MG1 accordingly functions as a generator and
regenerates the electrical energy Pm1 expressed as the product of
the torque Tm1 and the revolving speed Ns. The direction of the
torque output from the second motor MG2 is, on the other hand,
identical with the direction of the rotation of the rotor 142. The
second motor MG2 accordingly functions as a motor and consumes the
electrical energy Pm2 expressed as the product of the torque Tm2
and the revolving speed Nr.
Although the revolving speed Ns of the sun gear shaft 125C is
positive in the nomogram of FIG. 28, it may be negative according
to the revolving speed Ne of the engine 150 and the revolving speed
Nr of the ring gear shaft 126C as shown in the nomogram of FIG. 29.
In the latter case, the first motor MG1 applies the torque in the
direction of rotation of the rotor 132 and thereby works as a motor
to consume the electrical energy Pm1 given as the product of the
torque Tm1 and the revolving speed ns. The second motor MG2, on the
other hand, applies the torque in reverse of the rotation of the
rotor 142 and thereby works as a generator to regenerate the
electrical energy Pm2, which is given as the product of the torque
Tm2 and the revolving speed Nr, from the ring gear shaft 126C.
Like the operation principle of the power output apparatus 110 of
the first embodiment, the operation principle of the second
embodiment is on the assumption that the efficiency of power
conversion by the planetary gear 120, the motors MG1 and MG2, and
the transistors Tr1 through Tr16 is equal to the value `1`, which
represents 100%. In the actual state, however, the conversion
efficiency is less than the value `1`, and it is required to make
the energy Pe output from the engine 150 a little greater than the
energy Pr output to the ring gear shaft 126C or alternatively to
make the energy Pr output to the ring gear shaft 126C a little
smaller than the energy Pe output from the engine 150. As discussed
previously, the energy loss due to the mechanical friction in the
planetary gear 120 is significantly small and the synchronous
motors used as the motors MG1 and MG2 have the efficiency very
close to the value `1`, so that the efficiency of power conversion
is practically equal to the value `1`. For the matter of
convenience, in the following discussion of the second embodiment,
the efficiency is thus considered equal to the value `1` (=100%),
unless otherwise specified.
The braking control by the first motor MG1 and the engine 150
carried out in the power output apparatus 110 of the first
embodiment is applicable to the power output apparatus 110C of the
second embodiment, provided that the second motor MG2 is not
driven. The first motor MG1 is accordingly controlled to carry out
the regenerative operation or the power operation and enables a
braking force to be output to the ring gear shaft 126C. The braking
control by the first motor MG1 and the engine 150 has been
discussed in detail with the drawings of FIGS. 7 through 12, and is
not specifically described here. The following describes the
braking control by the first motor MG1, the second motor MG2, and
the engine 150 carried out in the power output apparatus 110C of
the second embodiment. Since the second motor MG2 is not attached
to the ring gear shaft 126C, the power output apparatus 110C of the
second embodiment can not carry out the braking control by the
second motor MG2.
In the braking control by the first motor MG1 and the engine 150
carried out in the power output apparatus 110 of the first
embodiment, the torque Tc acting as a reaction force is determined
corresponding to the preset revolving speed Ne of the engine 150 in
the graph of FIG. 10. The braking torque that can be output to the
ring gear shaft 126 thus depends upon the revolving speed Ne of the
engine 150. Namely the structure of the first embodiment can not
increase or decrease the braking force output to the ring gear
shaft 126 while keeping the revolving speed Ne of the engine 150
unchanged. In the power output apparatus 110C of the second
embodiment, on the other hand, the second motor MG2 is attached to
the crankshaft 156 of the engine 150 and can output the torque to
the crankshaft 156, thereby enabling the braking force output to
the ring gear shaft 126C to increase or decrease while keeping the
revolving speed Ne of the engine 150 unchanged. The revolving speed
of the engine 150 in the braking state can be set to a desired
level through the control of the second motor MG2. In the second
embodiment, the braking control by the first motor MG1, the second
motor MG2, and the engine 150 follows a torque control routine in a
braking state shown in the flowcharts of FIGS. 30 and 31 and a
continuous braking control routine shown in the flowchart of FIG.
34.
The torque control routine in the breaking state shown in the
flowcharts of FIGS. 30 and 31 is executed repeatedly at
predetermined time intervals (for example, at every 8 msec) while
the vehicle runs. When the program enters the routine of FIG. 30,
the control CPU 190 of the controller 180 first reads the revolving
speed Ne of the engine 150 at step S300. The revolving speed Ne of
the engine 150 may be calculated from the rotational angle .theta.c
of the crankshaft 156 measured by the resolver 157. Alternatively
the revolving speed Ne of the engine 150 may be measured directly
with the speed sensor 176 attached to the distributor 160. In the
latter case, the control CPU 190 receives data of the revolving
speed Ne from the EFIECU 170 connected to the speed sensor 176
through communication.
The control CPU 190 then reads the brake pedal position BP detected
by the brake pedal position sensor 165a at step S302, and
determines the braking torque Tr* to be output to the ring gear
shaft 126C, based on the input brake pedal position BP at step
S304. The procedure of determining the braking torque Tr* is
identical with that explained in the first embodiment. The control
CPU 190 subsequently reads the remaining charge BRM of the battery
194 measured by the remaining charge member 199 at step S306, and
compares the input remaining charge BRM of the battery 194 with the
threshold value Bref at step S308.
In case that the remaining charge BRM of the battery 194 is less
than the threshold value Bref at step S308, the program determines
the necessity for charging the battery 194 and sets a calculated
value according to the equation of Tm1*=Tr*.times..rho. to the
torque command value Tm1* of the first motor MG1 at step S310 while
setting a calculated value according to Equation (22) given below
to the torque command value Tm2* of the second motor MG2 at step
S312. The first term on the right side of Equation (22) is obtained
from the equilibrium on the dynamic collinear line shown in the
nomograms of FIGS. 28 and 29. The second term on the right side is
a proportional term to cancel the deviation of the revolving speed
Ne of the engine 150 from the value `0`, and the third term on the
right side is an integral term to cancel the stationary deviation.
In the stationary state (that is, when the revolving speed Ne of
the engine 150 is equal to zero), the torque command value Tm2* of
the second motor MG2 is set equal to the first term on the right
sides Tr*.times.(1+.rho.) obtained from the equilibrium on the
dynamic collinear line. K3 and K4 in Equation (22) denote
proportional constants.
Tm2*=Tr*.times.(1+.rho.)=K3.times.Ne-K4.intg.Nedt (22)
The control CPU 190 then outputs a signal for stopping the fuel
injection into the engine 150 from the communication port to the
EFIECU 170 at step S314 and controls the first motor MG1, the
second motor MG2, and the engine 150 based on the preset values at
steps S316 through S320. Like the first embodiment, although the
control operations of the first motor MG1, the second motor MG2,
and the engine 150 are shown as separate steps for convenience in
the second embodiment, these control operations in the actual state
are carried out in parallel and comprehensively. The control
procedures of the first motor MG1, the second motor MG2, and the
engine 150, a step S316 through S320 in the routine of FIG. 30 of
the second embodiment are identical with those at steps S134
through S138 in the torque control routine in the braking state of
the first embodiment shown in the flowchart of FIGS. 13 and 14, and
thus not specifically described here.
When the remaining charge BRM of the battery 194 is determined to
be less than the threshold value Bref at step S308, the control
procedure enables the dynamic collinear line to fall into the state
in which the engine 150 is at a stop, as shown in the nomogram of
FIG. 32. In this state, while the second motor MG2 outputs the
torque Tm2, the revolving speed Ne of the engine 150 is equal to
zero. The energy consumed by the second motor MG2 accordingly gives
a minimum value. Most of the energy generated by the braking
operation can thus be regenerated by the first motor MG1 as the
electrical energy, with which the battery 194 is charged. As
clearly understood from the nomogram of FIG. 32, the process of
locking up the second motor MG2 may substitute for the process of
setting the torque command value Tm2* of the second motor MG2 at
step S312.
In case that the remaining charge BRM of the battery 194 is not
less than the threshold value Bref at step S308, on the other hand,
the program determines no necessity for charging the battery 194
and carries out the processing of steps S330 through S338 shown in
the flowchart of FIG. 31. This processing sets the torque command
value Tm1* of the first motor MG1 and the torque command value Tm2*
of the second motor MG2, in order to enable a braking force to be
applied to the ring gear shaft 126C while not charging the battery
194. In the routine of FIG. 31, the control CPU 190 of the
controller 180 first reads the revolving speed Nr of the ring gear
shaft 126C at step S330, and calculates a braking energy Pr
required for braking by Pr=Tr*.times.Nr at step S332.
The control CPU 190 then sets the target torque Te* and the target
revolving speed Ne* of the engine 150 based on the calculated
braking energy Pr at step S334. The relationship between the
calculated braking energy Pr and the revolving speed Ne and the
torque Te of the engine 150 and the technique of determining the
target engine speed Ne* and the target engine torque Te* are
discussed previously at Step S144 in the torque control routine in
the braking state of the first embodiment shown in the flowcharts
of FIGS. 13 and 14.
The control CPU 190 subsequently sets a calculated value according
to the equation of Tm1*=Tr*.times..rho. to the torque command value
Tm1* of the first motor MG1 at step S336 while setting a calculated
value according to Equation (23) given below to the torque command
value Tm2* of the second motor MG2 at step S338. The first and the
second terms on the right side of Equation (23) are obtained from
the equilibrium on the dynamic collinear line shown in the nomogram
of FIG. 33. The third term on the right side is a proportional term
to cancel the deviation of the revolving speed Ne of the engine 150
from the target engine speed Ne*, and the fourth term on the right
side is an integral term to cancel the stationary deviation. The
nomogram of FIG. 33 shows the target driving state when the first
motor MG1, the second motor MG2, and the engine 150 are controlled
after the processing of steps S330 through S338.
Tm2*.rarw.Tr*x(1+.rho.)-Te*+K3(Ne*-Ne)+K4.intg.(Ne*-Ne)dt (23)
The control CPU 190 then outputs a signal for stopping the fuel
injection into the engine 150 from the communication port to the
EFIECU 170 at step S314 and controls the first motor MG1, the
second motor MG2, and the engine 150 based on the preset values at
steps S316 through S320.
The control procedure enables a divisional torque Ter (braking
torque Tr*) based on the torque Tc, which is the sum of the torque
Te working as a reaction and the torque Tm2 corresponding to the
torque command value Tm2* output from the second motor MG2, to be
applied to the ring gear shaft 126C, as shown in the nomogram of
FIG. 33. In the state of the nomogram of FIG. 33, the revolving
speed Ns of the sun gear shaft 125C is positive. The first motor
MG1 is accordingly controlled to carry out the power operation,
whereas the second motor MG2 is controlled to regenerate the
electrical energy Pm1 that is consumed by the first motor MG1. When
the revolving speed Ns of the sun gear shaft 125C is negative, on
the contrary, the first motor MG1 carries out the regenerative
operation and the second motor MG2 carries out the power operation
to consume the electrical energy Pm1 that is regenerated by the
first motor MG1.
When the remaining charge BRM of the battery 194 is determined to
be not less than the threshold value Bref at step S308, the second
motor MG2 regenerative or consumes the electrical energy Pm1 that
is consumed or regenerated by the first motor MG1. The battery 194
is thus neither charged nor discharged. This procedure enables a
desired braking force to be output to the ring gear shaft 126C
while neither charging nor discharging the battery 194.
In the torque control routine in the braking surface of the second
embodiment, when the remaining charge BRM of the battery 194 is
less than the threshold value Bref at step S308, the first motor
MG1 and the second motor MG2 are controlled to make the revolving
speed Ne of the engine 150 equal to zero. Another possible
procedure may, however, control the first motor MG1 and the second
motor MG2 to allow the engine 150 to be driven at a desired
revolving speed. In this case, the revolving speed Ne of the engine
150 is controlled to a predetermined value by regulating the
revolving speed Ns of the sun gear shaft 125C. For that purpose,
the processing of steps S180 through S188 in the modified torque
control routine in the braking state shown in the flowchart of FIG.
21 is applied to the structure of the second embodiment, in which
the second motor MG2 is attached to the crankshaft 156. The
modified procedure does not stop the operation of the engine 150
but allows the rotation of the engine 150 at a predetermined
revolving speed. When the driver steps on the accelerator pedal 164
in the course of the braking control, this modified structure
enables the required energy to be output from the engine 150
without delay.
The operation of applying a braking force to the ring gear shaft
126C irrespective of the step-on of the brake pedal 165 while the
vehicle runs down a long, continuous slope, follows a continuous
braking control routine shown in the flowchart of FIG. 34. Like the
continuous braking control routine of the first embodiment shown in
the flowchart of FIG. 24, this routine is executed when the driver
sets a continuous braking torque Tr2* and steps on neither the
accelerator pedal 164 nor the brake pedal 165. The continuous
braking torque Tr2* is set through an operation of a switch
disposed near the driver's seat. In the second embodiment, the
continuous braking torque Tr2* can be selected among three
different stages.
When the program enters the routine of FIG. 34, the control CPU 190
of the controller 180 first reads the continuous braking torque
Er2* at step S400, and receives the data of receiving speed Ne of
the engine 150 at step S402. The continuous braking torque Tr2* is
input in the same manner as the first embodiment. The control CPU
190 then reads the remaining charge BRM of the battery 194 detected
by the remaining charge meter 199 at step S404, and compares the
input remaining charge BRM with the threshold value Bref at step
S406.
In case that the remaining charge BRM of the battery 194 is not
less than the threshold value Bref at step S406, the program
determines no necessity for charging the battery 194 and carries
out the processing of steps S408 through S416 to set the torque
command value Tm1* of the first motor MG1 and the torque command
value Tm2* of the second motor MG2, so as to enable the continuous
braking torque Tr2* to be output to the ring gear shaft 126C while
neither charging nor discharging the battery 194. The processing of
steps S408 through S416 is identical with the processing of steps
S330 through S338 in the torque control routine in the braking
state shown in the flowcharts of FIGS. 30 and 31. The procedure of
setting the torque command value Tm1* of the first motor MG1 and
the torque command value Tm2* of the second motor MG2 in this
manner enables the continuous braking torque Tr2* to be output to
the ring gear shaft 126C while the battery 194 is kept intact, as
discussed previously.
In case that the remaining charge BRM of the battery 194 is less
than the threshold value Bref at step S406, on the other hand, the
program determines the necessity for charging the battery 194 and
sets a calculated value according to the equation of
Tm1*=Tr2*.times..rho. to the torque command value Tm1* of the first
motor MG1 at step S418 while setting a calculated value according
to Equation (22) to the torque command value Tm2* of the second
motor MG2 at step S420. The processing of steps S418 and S420 is
equivalent to the processing of steps S310 and S312 in the torque
control routine in the braking state shown in the flowcharts of
FIGS. 30 and 31. As discussed previously, the procedure of setting
the torque command value Tm1* of the first motor MG1 and the torque
command value Tm2* of the second motor MG2 in this manner enables
the continuous braking torque Tr2* to be output to the ring gear
shaft 126C while the battery 194 is charged.
After setting the torque command value Tm1* of the first motor MG1
and the torque command value Tm2* of the second motor MG2, the
program outputs a signal for stopping the fuel injection into the
engine 150 to the EFIECU 170 at step S422 and controls the first
motor MG1, the second motor MG2, and the engine 150 based on the
preset values at steps S424 through S428. The processing of steps
S424 through S428 is identical with the processing of steps S134
through S138 in the torque control routine in the braking state of
the first embodiment shown in the flowcharts of FIGS. 13 and
14.
The continuous braking control routine of the second embodiment
allows the torque corresponding to the preset continuous braking
torque Tr2* to be output to the ring gear shaft 126C even when the
driver does not step on the brake pedal 165. The vehicle can
accordingly run down a long, continuous slope without requiring the
driver to continue stepping on the brake pedal 165. The continuous
braking control routine is carried out while the driver steps on
neither the accelerator pedal 164 nor the brake pedal 165. This
accordingly does not interfere with the torque control in an
accelerating state based on the step-on amount of the accelerator
pedal 164 or with the torque control in a braking state based on
the step-on amount of the brake pedal 165.
This procedure can realize the braking control while the battery
194 is charged or while the battery 194 is kept intact, according
to the remaining charge BRM of the battery 194. This keeps the
remaining charge BRM of the battery 194 at the level of the
threshold value Bref.
Like the first embodiment, although the magnitude of the continuous
braking torque Tr2* is selected among the three different stages in
the second embodiment, it may be selected among a greater number of
stages or fixed to one stage. The continuous brake torque Tr2* may
be set based on the revolving speed of the driving wheels 116 and
118, that is, the revolving speed Nr of the ring gear shaft 126C,
or the rate of change of the revolving speed Nr. When the remaining
charge BRM of the battery 194 is less than the threshold value
Bref, the continuous braking control routine of the second
embodiment stops the operation of the engine 150. As discussed
previously, however, the revolving speed Ne of the engine 150 may
be set equal to a predetermined value. This structure enables the
engine 150 to output the required energy quickly in response to the
step-on of the accelerator pedal 164.
As discussed above, the power output apparatus 110C of the second
embodiment enables the braking torque Tr* or the continuous braking
torque Tr2* to be output to the ring gear shaft 126C by means of
the first motor MG1 and the engine 150 or by means of the first
motor MG1, the second motor MG2, and the engine 150. Another
possible structure outputs part of the braking torque Tr* or the
continuous braking torque Tr2* to the ring gear shaft 126C by means
of a mechanical friction brake while outputting the residual torque
by means of the first motor MG1, the second motor MG2, and the
engine 150.
In the power output apparatus 110C of the second embodiment, the
second motor MG2 is interposed between the engine 150 and the first
motor MG1. Like another power output apparatus 110D given as a
modified example in FIG. 35, however, the engine 150 may be
interposed between the first motor MG1 and the second motor MG2. In
the power output apparatus 110C of the second embodiment, the power
output to the ring gear shaft 126C is taken out of the arrangement
between the first motor MG1 and the second motor MG2 via the power
feed gear 128 linked with the ring gear 122. Like still another
power output apparatus 110E shown in FIG. 36 as another modified
example, however, the power may be taken out of the casing 119,
from which a ring gear shaft 126E is extended.
In the power output apparatus 110 of the first embodiment, the
power output apparatus 110C of the second embodiment, and their
modified examples, the crankshaft 156 is linked with the planetary
carrier 124 of the planetary gear 120, whereas the sun gear shaft
125 is linked with the first motor MG1 and the ring gear shaft 126
is linked with the power transmission gear 111, which connects with
the drive shaft 112 via the power fed gear 128. The crankshaft 156,
the first motor MG1, and the power transmission gear 111 may,
however, be linked with the three shafts of the planetary gear 120
in any desired combination. In any case, the input and output
powers, that is, the respective torque command values in each
torque control procedure, can be readily obtained from the
nomograms.
The present invention is not restricted to the above embodiments or
its modified examples, but there may be many modifications,
changes, and alterations without departing from the scope or spirit
of the main characteristics of the present invention.
The power output apparatus 110 of the first embodiment and its
modified examples discussed above are applied to the FR-type or
FF-type two-wheel-drive vehicle. In another modified example of
FIG. 37, however, a power output apparatus 110F is applied to a
four-wheel-drive vehicle. In this structure, the second motor MG2
is separated from the ring gear shaft 126 and independently
arranged in the rear-wheel portion of the vehicle, so as to drive
the rear driving wheels 117 and 119. The ring gear shaft 126 is, on
the other hand, connected to the differential gear 114 via the
power feed gear 128 and the power transmission gear 111, in order
to drive the four driving wheels 116 and 118. The torque control
procedures of the first embodiment are also applicable to this
structure.
Although the gasoline engine is used as the engine 150 in the power
output apparatus 110 of the first embodiment and the power output
apparatus 110C of the second embodiment, the principles of the
invention is also applicable to other internal combustion engines
and external combustion engines, such as Diesel engines, turbine
engines, and jet engines.
In the power output apparatus 110 of the first embodiment and the
power output apparatus 110C of the second embodiment, the planetary
gear 120 is used as the three shaft-type power input/output means.
Another available example is a double-pinion planetary gear having
plural sets of planetary pinion gears. One planetary pinion gear in
each pair is linked with the sun gear while the other is linked
with the ring gear, and the pair of planetary pinion gears are
linked with each other to revolve around the sun gear while
rotating on its axis. Any other device or gear unit, such as a
differential gear, is also applicable for the three shaft-type
power input/output means, as long as it can determine powers input
to and output from the residual one shaft based on predetermined
powers input to and output from any two shafts among the three
shafts.
Permanent mange (PM)-type synchronous motors are used as the first
motor MG1 and the second motor MG2 in the first and the second
embodiments discussed above. Any other motors which can implement
both the regenerative operation and the power operation, such as
variable reluctance (VR)-type synchronous motors, vernier motors,
d.c. motors, induction motors, superconducting motors, and stepping
motors, may, however, be used according to the requirements.
Transistor inverters are used as the first and the second driving
circuits 191 and 192 in the power output apparatus 110 of the first
embodiment and the power output apparatus 110C of the second
embodiment. Other available examples include IGBT (insulated gate
bipolar mode transistor) inverters, thyristor inverters, voltage
PWM (pulse width modulation) inverters, square-wave inverters
(voltage inverters and current inverters), and resonance
inverters.
The battery 194 in the above embodiments may include Pb cells, NiMH
cells, Li cells, or the like cells. A capacitor may be used in
place of the battery 194.
Although the power output apparatus is mounted on the vehicle in
all the above embodiments, it may be mounted on other
transportation means like ships and airplanes as well as a variety
of industrial machines.
It should be clearly understood that the above embodiments are only
illustrative and not restrictive in any sense. The scope and spirit
of the present invention are limited only by the terms of the
appended claims.
* * * * *