U.S. patent number RE42,131 [Application Number 12/114,207] was granted by the patent office on 2011-02-08 for fly-by-wire limp home and multi-plex system.
This patent grant is currently assigned to GM Global Technology Operations LLC. Invention is credited to Charles F. Long, Phillip F. McCauley, Scott E. Mundy, Jeffrey E. Shultz, Darren J. Weber.
United States Patent |
RE42,131 |
Long , et al. |
February 8, 2011 |
Fly-by-wire limp home and multi-plex system
Abstract
An electro-hydraulic control mechanism for use with a
multi-speed transmission includes a pair of logic valves, which are
manipulated during the ratio interchanges and the ratio
establishment by aiding in the distribution of fluid pressure from
a plurality of trim valves. The logic valves are retained in
specific drive ranges in the event of electrical
discontinuance.
Inventors: |
Long; Charles F. (Pittsboro,
IN), McCauley; Phillip F. (Zionsville, IN), Weber; Darren
J. (Indianapolis, IN), Mundy; Scott E. (Carmel, IN),
Shultz; Jeffrey E. (Zionsville, IN) |
Assignee: |
GM Global Technology Operations
LLC (Detroit, MI)
|
Family
ID: |
36262787 |
Appl.
No.: |
12/114,207 |
Filed: |
May 2, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
Reissue of: |
10975892 |
Oct 28, 2004 |
07140993 |
Nov 28, 2006 |
|
|
Current U.S.
Class: |
475/119;
475/128 |
Current CPC
Class: |
F16H
61/12 (20130101); F16H 61/686 (20130101); F16H
2200/0052 (20130101); F16H 2061/1232 (20130101); F16H
2061/1268 (20130101); F16H 2200/201 (20130101); F16H
61/0206 (20130101); F16H 2061/1292 (20130101) |
Current International
Class: |
F16H
31/00 (20060101) |
Field of
Search: |
;475/119,121-123,128
;477/906 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Ho; Ha D.
Attorney, Agent or Firm: Quinn Law Group, PLLC
Claims
The invention claimed is:
1. An electro-hydraulic apparatus for a power transmission having a
plurality of torque-transmitting mechanisms selectively engageable
by said apparatus to provide six forward ratio ranges, said
electro-hydraulic apparatus comprising: a supply of electrical
power to activate said electro-hydraulic apparatus; first and
second logic valves each positionable to a latched position and an
unlatched position; first and second trim valve.Iadd.s
.Iaddend..[.means.]. for providing maximum output pressure when
said electrical power is discontinued; third and fourth trim valves
controlled by normally closed solenoid valves that have a minimum
output pressure when said electrical power is discontinued; said
trim valves and said logic valves cooperating to provide control of
the torque-transmitting mechanisms to establish said six forward
ratios wherein said first trim valve is effective to maintain said
first logic valve in said latched position during the first,
second, third, and fourth of said forward ratio ranges, said second
trim valve is effective to maintain said second logic valve in said
latched position during the fourth, fifth, and sixth forward ratio
ranges; said first trim valve and said first logic valve being
effective to maintain a first of said torque-transmitting
mechanisms engaged during an electrical power discontinuance
occurring in either said third or fourth ratio range, said second
trim valve and said second logic valve being effective to maintain
a second of said torque-transmitting mechanisms engaged during an
electrical discontinuance occurring in said third ratio range, said
second trim valve and said second logic valve being effective to
maintain said second logic valve stroked and a third of said
torque-transmitting mechanisms engaged during an electrical
discontinuance occurring in said fourth ratio range, and said first
trim valve, said first logic valve in said unlatched position, and
said second logic valve in said latched condition cooperating to
maintain said second torque-transmitting mechanism engaged during
an electrical power discontinuance in said fifth ratio range; and
said electro-hydraulic apparatus being effective to maintain the
transmission in third ratio range in the event of an electrical
discontinuance during operation in either said first, second, or
third forward ratio range, in said fourth forward ratio range
during an electrical discontinuance during operation in said fourth
range, and in said fifth forward ratio range in the event of an
electrical discontinuance during operation in either said fifth or
sixth ratio range.
2. The electro-hydraulic apparatus for the power transmission
having the plurality of torque-transmitting mechanisms selectively
engageable by said apparatus to provide the six forward ratio
ranges, said electro-hydraulic apparatus defined in claim 1 further
comprising: means for urging said first and second logic valves to
said latched position during an interchange from a neutral
condition to said first forward range.
3. The electro-hydraulic apparatus for the power transmission
having the plurality of torque-transmitting mechanisms selectively
engageable by said apparatus to provide the six forward ratio
ranges, said electro-hydraulic apparatus defined in claim 1 further
comprising: means for urging said first and second logic valves to
said latched position during an interchange from a neutral
condition to said first forward range and said means being
discontinued during a ratio interchange from said fifth forward
ratio range to said sixth forward ratio range whereby said first
logic valve is moved to said unlatched position.
4. The electro-hydraulic apparatus for the power transmission
having the plurality of torque-transmitting mechanisms selectively
engageable by said apparatus to provide the six forward ratio
ranges, said electro-hydraulic apparatus defined in claim 1 further
comprising: means for urging said first and second logic valves to
said latched position during an interchange from a neutral
condition to said first forward range, and said means being
inoperative during an electrical discontinuance.
5. The electro-hydraulic apparatus for the power transmission
having the plurality of torque-transmitting mechanisms selectively
engageable by said apparatus to provide the six forward ratio
ranges, said electro-hydraulic apparatus defined in claim 1 further
comprising: means for urging said first and second logic valves to
said latched position during an interchange from a neutral
condition to said first forward range, said means being
discontinued during a ratio interchange from said fifth forward
ratio range to said sixth forward ratio range whereby said first
logic valve is moved to said unlatched position and said means
being inoperative during an electrical discontinuance.
.Iadd.6. An automatic transmission control apparatus comprising: a
source of fluid pressure; an exhaust apparatus; a first logic valve
having a spring set position and a pressure set position; a second
logic valve having a spring set position and a pressure set
position; a plurality of trim valves for supplying fluid pressure
to said logic valves, one of said trim valves being operable to
supply fluid pressure to said logic valves to urge said logic
valves to said pressure set position, said logic valves being
effective to distribute fluid pressure to a plurality of torque
transmitting mechanisms, said second logic valve being urged to
said spring set position when a second of said trim valves is
operated to engage a first of said torque transmitting mechanisms;
a diagnostic apparatus having a spring set condition and a pressure
set condition for issuing a signal dependant on the operating
condition of said torque transmitting mechanisms; and said
diagnostic apparatus being urged to said pressure set condition
when said second logic valve is held in said spring set position
and a first of said torque transmitting mechanisms is engaged and
being in said spring set position when said first
torque-transmitting mechanism is not engaged..Iaddend.
.Iadd.7. An automatic transmission control apparatus comprising: a
source of fluid pressure; an exhaust apparatus; a first logic valve
having a spring set position and a pressure set position; a second
logic valve having a spring set position and a pressure set
position; a plurality of trim valves for supplying fluid pressure
to said logic valves, one of said trim valves being operable to
supply fluid pressure to said logic valves to urge said logic
valves to said pressure set position, said logic valves being
effective to distribute fluid pressure to a plurality of torque
transmitting mechanisms, said second logic valve being urged to
said spring set position when a second of said trim valves is
operated to engage a first of said torque transmitting mechanisms;
a diagnostic apparatus having a spring set condition and a pressure
set condition for issuing a signal dependant on the operating
condition of said torque transmitting mechanisms; and said
diagnostic apparatus being connected with said exhaust apparatus
when said first logic valve is in said spring set position and said
diagnostic apparatus is in said spring set position..Iaddend.
.Iadd.8. An automatic transmission control apparatus comprising: a
source of fluid pressure; an exhaust apparatus; a first logic valve
having a spring set position and a pressure set position; a second
logic valve having a spring set position and a pressure set
position; a plurality of trim valves for supplying fluid pressure
to said logic valves, one of said trim valves being operable to
supply fluid pressure to said logic valves to urge said logic
valves to said pressure set position, said logic valves being
effective to distribute fluid pressure to a plurality of torque
transmitting mechanisms, said second logic valve being urged to
said spring set position when a second of said trim valves is
operated to engage a first of said torque transmitting mechanisms;
a diagnostic apparatus having a spring set condition and a pressure
set condition for issuing a signal dependant on the operating
condition of said torque transmitting mechanisms; and said
diagnostic apparatus being urged to said pressure set condition
when said second logic valve is held in said spring set position
and a first of said torque transmitting mechanisms is engaged, said
diagnostic apparatus being connected with said exhaust apparatus
when said first logic valve is in said spring set position and said
diagnostic apparatus is in said spring set position, and said
diagnostic apparatus being connected with said pressure source when
both of said logic valves are in said pressure set
position..Iaddend.
.Iadd.9. The automatic transmission control apparatus defined in
claim 8 further comprising: said diagnostic apparatus being
connected with said exhaust apparatus when said first logic valve
is in said pressure set opposition and said second logic valve is
in said spring set position..Iaddend.
Description
TECHNICAL FIELD
This invention relates to electro-hydraulic controls for
transmissions, and more particularly, to controls having electronic
mechanisms.
BACKGROUND OF THE INVENTION
Many of the currently-available high performance planetary
transmissions employ what is termed clutch-to-clutch shifting. This
term indicates that the ratio change is performed by disengaging
one disc-type friction device while engaging another disc-type
friction device. This is accomplished without the use of one-way
devices. Therefore, the overlap control needs to be quite accurate
in these situations and the position of the control must also be
accurate.
At least one planetary transmission that is utilized with
clutch-to-clutch shifting controls is shown in U.S. Pat. No.
4,070,927 issued to Polak on Jan. 31, 1978. This transmission has a
control that is equipped with solenoid controlled trim valves that
are actuated by electronic control units to provide engagement and
disengagement pressures for the torque-transmitting friction
devices within the transmission. One such solenoid control is shown
in U.S. Pat. No. 5,601,506 issued to Long et al. on Feb. 11, 1997.
Also, the transmissions in this category use what is known as skip
shifting, that is, a first-to-third ratio interchange or a
second-to-fourth ratio interchange. The above-identified Long et
al. patent does not provide for skip shifting.
It is also desirable to ensure that the vehicle incorporating these
transmissions can be returned to a repair facility in the event of
a discontinuance of electrical power, which is known as limp home
capability. Such control systems can be found in U.S. Pat. No.
4,827,806 issued to Long et al. on May 9, 1989, and U.S. Pat. No.
5,616,093 also issued to Long et al. on Apr. 1, 1997.
The transmission controls utilize trim valves, which are operating
in combination with shift valves to control the on-coming and
off-going friction devices. The trim valves are equipped with
variable pressure solenoids while the shift valves are controlled
by on/off-type solenoid valves.
U.S. Pat. No. 6,520,881 issued to Long et al. on Feb. 18, 2003,
describes a control system wherein four solenoid valves control
four trim valves, which in turn control the on-coming and off-going
pressures in five torque-transmitting mechanisms. This control
mechanism incorporates two latching valves, which are multi-plexed
to control fluid pressure distribution to three torque-transmitting
mechanisms. Limp home capability is provided by the control system
disclosed in this Patent. The control of U.S. Pat. No. 6,520,881
will permit limp home capability in either the third or fifth
forward ranges
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an improved
electro-hydraulic control mechanism for a multi-speed power
transmission having limp home capability.
In one aspect of the present invention, a pair of logic valves that
are positionable to direct fluid to the desired torque-transmitting
mechanisms, during normal operation, will assume a neutral
condition in the event of electrical discontinuance from either
neutral or reverse range.
In another aspect of the present invention, the logic valves will
assume a third range condition in the event of electrical
discontinuance of electrical signals during normal operation in
either first, second, or third range.
In yet another aspect of the present invention, the logic valves
will assume a fourth range condition in the event of electrical
discontinuance during normal fourth range operation.
In still another aspect of the present invention, the logic valves
will assume a fifth range condition in the event of electrical
discontinuance during normal operation in either fifth or sixth
range.
.Iadd.An improved electro-hydraulic control mechanism for a
multi-speed power transmission is provided having a multi-clutched
diagnostic system.
In one exemplary embodiment, a diagnostic valve is displaced within
the hydraulic portion of the transmission and is positionable by
fluid pressure within the transmission control system.
In one exemplary embodiment, the diagnostic valve also incorporates
or has associated therewith an electronic or electric switch
mechanism, which signifies the pressure available at the diagnostic
valve.
In one exemplary embodiment, fluid pressure from a control circuit
is continuously fed by a control pressure, which is directed
through a restricted passage prior to reaching the diagnostic valve
and the switch.
In one exemplary embodiment, the diagnostic valve is operably
hydraulically connected with two logic control valves in the
transmission control system..Iaddend.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic representation showing a multi-speed power
transmission incorporating the present invention.
FIG. 2 is a diagrammatic representation of an electronic control
system incorporating the present invention and utilized with the
power transmission shown in FIG. 1 and conditioned for neutral.
FIG. 3 is a diagrammatic representation of an electronic control
system incorporating the present invention and utilized with the
power transmission shown in FIG. 1 and conditioned for reverse.
FIG. 4 is a diagrammatic representation of an electronic control
system incorporating the present invention and utilized with the
power transmission shown in FIG. 1 and conditioned for first.
FIG. 5 is a diagrammatic representation of an electronic control
system incorporating the present invention and utilized with the
power transmission shown in FIG. 1 and conditioned for fourth.
FIG. 6 is a diagrammatic representation of an electronic control
system incorporating the present invention and utilized with the
power transmission shown in FIG. 1 and conditioned for sixth.
FIG. 7 is a diagrammatic representation of an electronic control
system incorporating the present invention and utilized with the
power transmission shown in FIG. 1 and conditioned for
reverse/neutral power off.
FIG. 8 is a diagrammatic representation of an electronic control
system incorporating the present invention and utilized with the
power transmission shown in FIG. 1 and conditioned for first
through third power off.
FIG. 9 is a diagrammatic representation of an electronic control
system incorporating the present invention and utilized with the
power transmission shown in FIG. 1 and conditioned for fourth power
off.
FIG. 10 is a diagrammatic representation of an electronic control
system incorporating the present invention and utilized with the
power transmission shown in FIG. 1 and conditioned for fifth and
sixth power off.
DESCRIPTION OF AN EXEMPLARY EMBODIMENT
A power transmission shown in FIG. 1 includes an engine and torque
converter (TC), an input shaft 10, an output shaft 12, and three
planetary gearsets 14, 16, and 18. The planetary gearsets 14, 16,
and 18 are controlled to provide six forward speed ratios, a
reverse speed ratio, and a neutral condition between the input
shaft 10 and the output shaft 12. These conditions are provided by
five torque-transmitting mechanisms C1, C2, C3, C4, and C5. The
torque-transmitting mechanisms C1 and C2 are rotating-type
torque-transmitting mechanisms commonly termed clutches, and the
torque-transmitting mechanisms C3, C4, and C5 are stationary-type
torque-transmitting mechanisms commonly termed reaction clutches or
brakes.
To establish a reverse ratio, the torque-transmitting mechanisms C3
and C5 are engaged. In the neutral condition, the
torque-transmitting mechanism C5 is engaged. During the neutral to
first ratio interchange, the solenoid is activated to place the
logic valve 30 in the stroked position. For the first forward
ratio, the torque-transmitting mechanisms C1 and C5 are engaged.
During the first to second interchange, the solenoid 72 is
deactivated but the logic valve 30 is latched by the pressure
acting on the differential area between lands 30B and 30C. To
establish the second forward ratio, the torque-transmitting
mechanisms C1 and C4 are engaged, and the solenoid valve is
activated to place the logic valve 80 in the stroked position. To
establish the third forward range, the torque-transmitting
mechanisms C1 and C3 are engaged. The torque-transmitting mechanism
C3 is controlled by the trim valve 34. To establish the fourth
forward range, the torque-transmitting mechanisms C1 and C2 are
engaged. Engagement of the torque-transmitting mechanism C2 latches
the logic valve 80 in the stroked position. During the fifth
forward range, the torque-transmitting mechanisms C2 and C3 are
engaged. The trim valve 38, which was on in the fourth range, is
turned off and the latch pressure on the logic valve 30 is
released. During the sixth range, the torque-transmitting
mechanisms C2 and C4 are engaged. The logic valve 30 is conditioned
by the solenoid 72 to a low pressure state. A more complete
description of the power transmission can be found in U.S. Pat. No.
4,070,925.
The torque-transmitting mechanisms C1, C2, C3, C4, and C5 are all
selectively engageable hydraulically controlled torque-transmitting
mechanisms, which are well known in the art of power transmissions.
The hydraulic fluid to engage these torque-transmitting mechanisms
is provided by an electro-hydraulic control mechanism 20 that
includes an electronic control unit (ECU) which incorporates a
programmable digital computer to provide electronic signals to a
hydraulic control (HYD) which in turn distributes the hydraulic
fluid to various torque-transmitting mechanisms as required by the
driving conditions.
The ECU receives a number of input signals from the engine, torque
converter, and also the transmission elements in the vehicle, which
partially determine the electronic signals that are generated and
distributed to the hydraulic system to provide for upshifting and
downshifting of the transmission by controlling the engagement and
disengagement of the torque-transmitting mechanisms.
As seen in FIG. 2, the hydraulic portion of the electro-hydraulic
control 20 includes a pump 22, which withdraws hydraulic fluid from
a reservoir 24 for distribution through a main passage 26. The main
passage 26 is in continuous fluid communication with a main
regulator valve 28 and five trim valves 32, 34, 36, 38, and 40, and
a control regulator valve 42. The main regulator valve 28 is
effective to set the maximum system pressure within the passage 26.
The main regulator valve 28 has a bias area 44 on the upper end of
the valve 28, a differential bias area 46 that is in fluid
communication with a latch or logic valve 30 through a passage 48.
The valve 28 has a second differential bias area 46A that is in
fluid communication with a passage 50.
The pressure regulator valve 28 supplies fluid pressure to the main
passage 26 and when the pressure in that passage has been
satisfied, the regulator valve 28 distributes fluid pressure to a
passage 52 that is in communication with a torque converter flow
valve 54 which in turn communicates with a converter regulator
valve 56 which in turn distributes fluid to a torque converter
(TC). If there is excess fluid after the torque converter (TC) is
satisfied, the remaining fluid is distributed through the sump 24
to a return passage 58.
The passage 50 is also in communication with a line modulator valve
59. The line modulator valve 59 is a conventional solenoid
controlled valve, which is a normally closed valve; that is, the
fluid pressure in passage 50 is essentially zero when the line
modulator valve 59 is inoperable
The solenoid valve 62 is controlled by the ECU to establish a
control pressure in a passage 74, which determines the fluid
pressure distributed from the trim valve 32 to a passage 76, which
is in communication with a latch or logic valve 80. The solenoid
valve 62 is a normally on solenoid that has maximum output pressure
when there is no electrical power delivered thereto. The solenoid
valve 64 distributes fluid pressure in a passage 77 that is
distributed to trim valve 34 to control the pressure in a passage
78, which is in fluid communication with the logic valves 30 and
80. The solenoid valve 66 controls fluid pressure in a passage 82,
which is effective to establish the output pressure of the trim
valve 36 and a passage 84 that is in fluid communication with the
torque-transmitting mechanism C4. The solenoid valves 64, and 66
are normally off mechanisms. The solenoid valve 68 distributes
fluid pressure to a passage 86, which is effective to establish the
output pressure of the trim valve 38, which is distributed through
a passage 88 to the logic valve 30. The solenoid valve 68 is a
normally on mechanism, thus producing a maximum output signal when
the electrical signal is off. The solenoid valve 70, a normally off
solenoid, is effective to control pressure in a passage 90, which
establishes an outlet pressure of the trim valve 40 in a passage 91
for distribution through the converter flow valve 54 and a torque
converter clutch (LU) 94. When the converter flow valve 54 is in
the spring set position shown, the pressure in passage 52 is
distributed through the valve 54 and the valve 56 to the torque
converter (TC).
Flow out of the torque converter (TC) is distributed through a
return passage 96 and through the converter flow valve 54 to a
cooler 98. The fluid returning from the cooler 98 passes through a
lube circuit 100, which distributes fluid to lubricate the various
components of the transmission such as gears and bearings.
The logic valve 30 includes a valve spool 30A, which is slidably
disposed in a valve bore and urged to a spring set position shown
by a spring 102 and to a pressure set position by fluid pressure
acting in a passage 104 on the upper end of the valve spool 30. The
passage 104 communicates with the solenoid valve 72, which is a
conventional on/off-type solenoid valve such that the fluid
pressure in passage 104 is either essentially zero or an
established control pressure, which is set in passage 60 by the
control regulator valve 42. The solenoid 72 is a normally off
device. The spring 102 is disposed within a spring chamber 103.
As mentioned above, the solenoid valve 72 is an on/off-type
solenoid and while the solenoid valves 62, 64, 66, 68, and 70 are
variable type solenoid valves, which distribute a variable control
signal depending upon the electrical signal received from the
electronic control unit. The solenoid valves 62 and 68 are normally
open-type valves, which means that the control signal generated
from these valves is maximum when the electronic signal conducted
thereto is minimum. The solenoid valves 64, 66, and 70 are normally
off-type solenoid valves, which means that the pressure distributed
thereby is minimum when the electronic control signal directed
thereto is minimum.
In the spring set position shown, the fluid in passage 88 is
distributed through the valve 30 to a passage 106, which
communicates with the logic valve 80. The logic valve 30 has four
lands formed thereon, 30B, 30C, 30D, and 30E. The logic valve 80
has a valve spool 80A, which includes five valve lands 80B, 80C,
80D, 80E, and 80F. The valve spool 80A is operated on by a spring
116 which is disposed in a spring pocket or chamber 122. The
passage 48 communicates between the passages 30D and 30E of the
valve spool 30A in the spring set position with a passage 108,
which in turn communicates between passages 80B and 80C in the
spring set position of valve 80, and with an exhaust passage 112,
which also communicates between the lands 30B and 30C through a
passage 110 with the torque-transmitting mechanism C1. Thus, in the
spring set position of the valves 30 and 80, the
torque-transmitting mechanism C1 and C2 inoperable.
The passage 112 communicates with an exhaust valve 114, the trim
valves 32, 34, 36, and 38, and the control regulator valve 42. The
exhaust valve 114 establishes a minimum pressure within the control
system such that the torque-transmitting mechanisms have disposed
therein or fed thereto a minimum pressure, which simplifies the
engagement and disengagement control of the torque-transmitting
mechanism. The use of a back fill exhaust valve to maintain a
minimum pressure within torque-transmitting mechanisms is well
known in the art.
The control regulator valve 42, as previously mentioned,
distributes a reduced pressure from the main pressure in passage 26
to the passage 60. Passage 60 communicates with the solenoid valves
62, 64, 66, 68, 70, and 72. The solenoid valves operate in a
well-known manner to control the output pressure from the
respective valves to their control passages by reducing the
pressure in passage 60 to the respective output pressures of the
solenoid valves. The passage 60 also communicates with the logic
valve 30. The logic valve 30 blocks the passage 60 in the spring
set position by the valve land 30E. The passage 60 also
communicates through a multiple restriction 115 with a passage 117,
which communicates in turn with a diagnostic valve 119.
The diagnostic valve 119 has a valve spool 121, which includes
spaced valve lands 123 and 125. The passage 117 communicates
between the valve lands 123 and 125 and in the pressure set
position shown in FIG. 2, communicates between the valve lands 123
and 125 with a pressure switch 130. The pressure switch 130 is
connected with the ECU and provides a signal thereto which
indicates the pressure in the passage 117.
The diagnostic valve 119 also communicates with a passage 132,
which is connected with the trim valve 32 and with a passage 134,
which communicates with the spring chamber 103 of valve 30. The
spring chamber 103 also communicates with the passage 112, which in
turn communicates with the logic valve 80. In the pressure set
position of the valve 119, the valve land 125 blocks the passage
134 from reaching the passage 117 while the passage 132 is open
between the valve lands 123 and 125 with the passage 117. Thus,
when valve 32 is in the spring set position, the pressure at the
switch 130 is at an exhaust value, which is determined by the
pressure in the passage 132. In the spring set position of the
diagnostic valve 119, the pressure in the passage 117 and therefore
the switch 130 is determined by the pressure in passage 134.
The passage 112 communicates with the logic valves 30 and 80 in a
plurality of locations. In the spring set position shown for the
valves 30 and 80, the exhaust passage 112 communicates between the
lands 30B and 30C and between the lands 80B and 80C. The exhaust
passage 112 also communicates between the lands 80D and 80E when
the valve 80 is in the spring set position. Thus, in the spring set
position for both valves 30 and 80, the passage 112 communicates
with the passage 134, which will connect with the diagnostic switch
130 when the valve 119 is in the spring set position.
The logic valve 80 communicates with the torque-transmitting
mechanism C2 through a passage 118, with the torque-transmitting
mechanism C3 through a passage 136, and with the
torque-transmitting mechanism C5 through a passage 120. The passage
120 communicates with the spring chamber 122 and in a spring set
position of valve 80 communicates with a passage 78, which in turn
delivers fluid pressure from the trim valve 34. The passage 76,
which distributes fluid pressure from the trim valve 32
communicates with the logic valve 80 in the spring set position
between the lands 80C and 80D, which in turn communicates with the
passage 136 and therefore torque-transmitting mechanism C3.
In the pressure set position of the logic valve 80, the passage 76
communicates between the lands 80B and 80C with the
torque-transmitting mechanism C2. It will be noted that the land
80B is smaller in diameter than the land 80C, thus once the valve
80 is in the pressure set position and the torque-transmitting
mechanism C2 is engaged, the pressure in passages 76 and 118 will
latch the valve 80 in the pressure set position.
The logic valve 30 is in fluid communication with the passage 88
between the lands 30C and 30D in the spring set position of valve
spool 30A. The passage 88, as previously commented, delivers
control fluid pressure from the trim valve 38. The pressure in
passage 88 is distributed between the valves 30C and 30D to the
passage 106 when the valve 30 is in the spring set position.
Passage 106 is blocked by the land 80D when the valve 80 is in the
spring set position. However, when the valve 80 is in the pressure
set position, the passage 106 communicates with the
torque-transmitting mechanism C3. In the spring set position of the
valve 80, the passage 76 is fluid communication with the
torque-transmitting mechanism C3.
As noted, the hydraulic control shown in FIG. 2 is in the neutral
condition. In this condition, the torque-transmitting mechanism C5
is held in controlled engagement by the trim valve 34 through the
passage 78 between the lands 80E and 80F in the passage 120. The
passage 120 also communicates with the diagnostic valve 119, which
places the valve 119 in the pressure set position. In the neutral
condition, the trim valve 32 is inoperable and therefore the
passage 76 is connected with exhaust through the trim valve 32.
To condition the transmission for reverse operation, the trim valve
32 is made active by the solenoid 62, which does two things. First,
it distributes control fluid pressure through the passage 76 to the
torque-transmitting mechanism C3 through the logic valve 80 to
enforce engagement thereof. When the torque-transmitting mechanisms
C3 and C5 are engaged, the transmission shown in FIG. 1 is
conditioned for reverse second, the trim valve 32 blocks the
exhaust of passage 132 and therefore prevents flow of fluid through
the restriction 115, which of course raises the pressure within the
passages 117 and 132 and the diagnostic switch 130. Thus, in
reverse, the diagnostic switch 130 is energized indicating to the
control system that the system is operating properly in
reverse.
To establish the first and lowest forward range, the control
mechanism is operated to engage the torque-transmitting mechanism
C1 through the operation of the trim valve 38 which is responsive
to the control pressure from the solenoid valve 68. When the
transmission is shifted from the neutral to the forward range, the
solenoid valve 72 is energized, which emits a control pressure to
the passage 104 and to the valve lands 80B and 30B. In the first
range of operation, the logic valve 30 is shifted to the pressure
set position. However, the logic valve 80 cannot shift to the
pressure set position because of the fluid pressure in the spring
chamber 122, which is equal to the pressure in the
torque-transmitting mechanism C5 and establishes a greater force on
the valve spool 80A than the pressure acting on the valve land 80B.
The trim valve 68 is operated to control the engagement of the
torque-transmitting mechanism C1 such that the transmission
operates in the first forward range. When the trim valve 38
energizes the torque-transmitting mechanism C1, the trim valve 32
de-energizes the torque-transmitting mechanism C3, thus returning
the passage 132 to the exhaust condition, which exhausts the
diagnostic switch 130 and the passage 117, and informs the ECU that
the reverse range of operation has been de-activated. When the
transmission is operating in first range, fluid pressure in the
passage 60 is directed through the valve 30 between the lands 30D
and 30E to the passage 48 and the bias area 46 thereby affecting
the regulation pressure of the system at the regulator valve 28. In
first range, the maximum system pressure is reduced by the bias
pressure.
During a ratio interchange from first-to-second, the
torque-transmitting mechanism C4 is brought into controlled
engagement by the trim valve 36 while the torque-transmitting
mechanism C5 is disengaged in a controlled manner by the trim valve
34. Upon completion of the first-to-second interchange, the
torque-transmitting mechanism C5 is fully disengaged such that the
logic valve 80 is moved to the pressure set position. When the
torque-transmitting mechanism C5 is disengaged, the diagnostic
valve 119 is moved to the spring set position thereby permitting
fluid pressure to be developed within the passage 117 and also
within the passage 134. The switch is now activated indicating the
stroke of the valve 80 has been completed
In the third range of operation, the logic valves 30 and 80 are
both in the pressure set position thereby permitting the trim valve
34 to control the engagement of the torque-transmitting mechanism
C3. This control pressure is effective in the passage 78 between
the lands 30C and 30D and into passage 106 and then between lands
30C and 30D into the passage 136 and torque-transmitting mechanism
C3. During the third range of operation, the diagnostic valve 119
remains in the spring set position and the switch 130 remains
activated.
As the ratio interchange from third range to fourth range is
accomplished by controlled disengagement of the torque-transmitting
mechanism C3 by the trim valve 34 and the controlled engagement of
the torque-transmitting mechanism C2 by the trim valve 32, the trim
valve 32 distributes pressure through the passage 76 between the
lands 80B and 80C through the passage 118 and thus the
torque-transmitting mechanism C2. During the fourth range of
operation, the diagnostic valve 119 remains in the spring set
position and the switch 130 remains activated and the fluid
pressure on the bias 46 remains controlled.
The fifth range of forward operation is established by the
controlled disengagement of the torque-transmitting mechanism C 1
by operation of the trim valve 38, and the controlled engagement of
the torque-transmitting mechanism C3 by the controlled operation of
the trim valve 34. As with the third range of operation, the
torque-transmitting mechanism C3 is engaged by the fluid pressure
in passage 78 passing through the logic valve 30 to the passage 106
and then through the logic valve 80 to the passage 136. During the
fifth range of operation, the diagnostic valve 119 remains in the
spring set position and the switch 130 remains pressurized or
activated.
The sixth range of operation is established by the controlled
disengagement of the torque-transmitting mechanism C3 by the trim
valve 34 and the controlled engagement of the torque-transmitting
mechanism C4 by the trim valve 36. During the fifth ratio to sixth
ratio interchange, the diagnostic valve 119 remains in the spring
set position and the switch 130 remains activated. However, upon
reaching the sixth range of operation, the solenoid valve 72 is
conditioned to the "off" mode thereby eliminating the pressure bias
on the valve lands 30B and 80B. The valve 80 remains in the latched
condition due to the pressure in the torque-transmitting mechanism
C2, which operates on the bias area between valve lands 80B and
80C. The logic valve 30, however, has no such bias at this point
and returns to the spring set position. In the spring set position,
the spring chamber 103 communicates with the passage 134 and
thereby exhausts the pressure within that passage such that
insufficient flow through the restriction 115 is permitted and the
diagnostic switch 130 is moved to the "off" position or deactivated
condition indicating that the valve 30 has moved to the spring set
position.
Thus, as described above, the diagnostic pressure switch 130 is
activated during reverse, is deactivated during neutral, is
deactivated during the first-to-second ratio interchange, is
activated during the second range, is activated during the
fifth-to-sixth ratio interchange, and is deactivated upon achieving
sixth range.
When operating in reverse, if the electronic power should be
discontinued for some reason, the solenoid valves 62 and 68 will
produce maximum outlet pressure at their respective trim valves 32
and 38. Thus, should the power be eliminated in reverse or neutral,
the torque-transmitting mechanism C3 is engaged by the trim valve
32 while all other torque-transmitting mechanisms are discontinued.
Also, under this condition, should the power be eliminated, the
passage 134 is connected through the spring chamber 103 with the
exhaust passage 112 and therefore the diagnostic switch 130 is
deactivated indicating that the reverse ratio has not been achieved
since during normal operation the switch is activated in
reverse.
Should a power discontinuance occur during first through third
forward ratios, the trim valve 38 will maintain the
torque-transmitting mechanism C1 engaged, however, the logic valve
80 will return to the spring set position due to loss of control
pressure on land 80B and the trim valve 32 will engage the
torque-transmitting mechanism C3 thereby conditioning the
transmission to third ratio, however, the passage 134 is exhausted
through the logic valve 80 between lands 80D and 80E, which
communicates with the exhaust passage 112. Thus, on a power
discontinuance at the control system, the switch 130 will be
deactivated, however, the transmission control will indicate third
ratio and since the switch 130 should be activated, the operator
will be informed that some malfunction has occurred within the
transmission control.
If an electronic malfunction should occur during fourth ratio, the
valves 30 and 80 will both have been latched in the pressure set
condition and will remain that way since the trim valves 32 and 38
will charge the differential areas of the respective logic valves
during minimum electronic input to the solenoid valves 62 and 68.
If a malfunction should occur during fifth ratio or sixth ratio,
the torque-transmitting mechanism C2, which was in a latched
condition during fifth or sixth ratio, will remain so since the
fluid pressure distributed by the trim valve 32 will remain at
maximum, and the trim valve 38 will distribute maximum pressure
through the passage 88 which connects between the lands 30C and 30D
of the logic valve 30 with the passage 106 and then between the
lands 80C and 80D through the torque-transmitting mechanism C3.
Note that on a malfunction, the hydraulic bias through the logic
valves 30 and 80 is discontinued and this pressure is discontinued
during sixth range of operation in any situation.
The passage 134 will be exhausted through the spring chamber 103,
thus deactivating the switch 130. However, the transmission will
indicate that fifth range of operation is attained but the switch
130 is de-energized and therefore a malfunction has occurred and
the system will inform the operator of this condition.
Upon the recognition of a malfunction, the diagnostic switch 130
can be interrogated under various conditions to determine where the
malfunction might be. During the diagnostics, the
torque-transmitting mechanism C5 is engaged thereby placing the
diagnostic valve 119 in the pressure set position. If the solenoid
valve 62 has malfunctioned to the closed position, the trim valve
32 will not issue a control pressure and the switch 130 will be
exhausted through the passage 132. If the solenoid 62 cannot be
taken from the high state, the maximum output pressure will be
produced at the trim valve 32 thereby blocking the passage 132 from
the valve 119 indicating that the trim valve is pressurized when in
fact the command is calling for it to be depressurized.
Also, during diagnostic testing, the torque-transmitting mechanism
C5 can be placed in the unapplied position and if both valves 30
and 80 are destroked to the spring set position, the switch 130 is
exhausted and remains in the de-energized state. If the logic valve
30 is stroked to the pressure set position and the logic valve 80
is spring set, the switch 130 is exhausted through the logic valve
80 and will remain in the de-energized state. If the logic valve 80
is stroked to the pressure set position and the logic valve 30 is
destroked, this will allow the diagnostic switch 130 to be
exhausted to the logic valve 30 and the valve will remain in the
de-energized state. If both the logic valves 30 and 80 are in the
latched or stroked position, this blocks the exhaust path for the
pressure switch and results in pressure switch actuation.
These diagnostic techniques thereby indicate the positioning of the
valves and permit the diagnostician to determine where a
malfunction may have occurred. There are three times when it is
important that malfunctions are detected. In neutral, a single
point malfunction in the control circuit or trim valve 32 could
permit a shift to reverse, however, the pressure at the switch 130
will detect this before the fill begins to prevent such action
knowing that a neutral condition has been commanded. The logic
valve 80 goes through transition after the first-to-second shift
and before the second-to-first shift. The pressure switch changes
state during this transition and thereby provides a positive
feedback to the electronic control mechanism to inform the system
that the shift is occurring. The logic valve 30 undergoes a
transition after the fifth-to-sixth interchange and before the
sixth-to-fifth interchange. The diagnostic switch 130 changes
states during the transition and thereby provides a feedback signal
to the electronic control mechanism to indicate that the shift is
occurring.
In FIG. 3, the electro-hydraulic control is shown in the Reverse
ratio operation. Both of the logic valves 30 and 80 are in the
unstroked position, the trim valve 34 supplies fluid to the
torque-transmitting mechanism C5, and the trim valve 32 supplies
fluid to the torque-transmitting mechanism C3. In FIG. 4, the
electro-hydraulic control is shown in the first forward range. The
logic valve 80 is blocked in the unstroked position by pressure at
torque-transmitting mechanism C5 and the torque-transmitting
mechanism C1 is supplied by the trim valve 38, and the solenoid
valve 72 is actuated during the neutral to first range interchange.
The pressure from the trim valve 38 latches the logic valve 30 in
the stroked position.
FIG. 5 displays the electro-hydraulic control in the fourth forward
range. The logic valve 80 is in the stroked position since the
latching pressure at torque-transmitting mechanism C5 was released
during a first to second interchange. The torque-transmitting
mechanism C2 is engaged by the trim valve 32 and the logic valve 80
is latched in the stroked position. The torque-transmitting
mechanism C1 is controlled by the trim valve 38 and the logic valve
30 is latched in the stroked position. The electro-hydraulic
control is depicted in sixth forward range in FIG. 6. The
torque-transmitting mechanisms C2 and C4 are controlled by the trim
valves 32 and 36 respectively, and the solenoid valve 72 is
deactivated.
In the event of a unintended discontinuance electrical power to the
solenoids 62, 64, 66, 68, 70, and 72, the trim valves 32 and 38
will produce maximum output pressure. The remaining trim valves 34,
36, and 40 will have a minimum or zero output pressure. If this
discontinuance occurs during reverse or neutral operation, only the
torque-transmitting mechanism C3 will be engaged as shown in FIG.
7. If this discontinuance occurs during operation in the first,
second, or third forward ranges, the torque-transmitting mechanisms
C3 and C1 will be engaged as shown in FIG. 8. In each of these
ranges, the torque-transmitting mechanism C1 will have been engaged
prior to the discontinuance. The logic valve 80 will return to the
unstroked condition and the trim valve 32 will engage the
torque-transmitting mechanism C3.
In the event the discontinuance occurs during fourth range
operation, the electro-hydraulic control will be in the position
shown in FIG. 9. This position is the normal fourth range position
as described above in FIG. 5. The logic valves 30 and 80 are both
latched in the stroked position by the trim valves 38 and 32
respectively both before and after the discontinuance. If this
discontinuance occurs during the fifth or sixth forward ranges, the
electro-hydraulic control will be positioned as shown in FIG. 10
and the control will establish the fifth range. The
torque-transmitting mechanisms C2 and C3 will be engaged by the
trim valves 32 and 38 respectively. Prior to the discontinuance,
the logic valve 30 was de-latched during both fifth and sixth range
and will remain de-latched. The logic valve 80 was latched by the
trim valve 32 during normal operation in fourth, fifth, or sixth
ranges and will remain latched.
Following an unexpected discontinuance of electrical power, the
electro-hydraulic control will remain in one of the above described
conditions (third, fourth, or fifth range) until the engine
operation is ceased. This will permit moving of the vehicle in the
forward direction to a repair facility where the engine operation
can be discontinued, the problem analyzed and the control
repaired.
* * * * *