U.S. patent application number 11/359620 was filed with the patent office on 2006-08-31 for control device of automatic transmission.
This patent application is currently assigned to DENSO CORPORATION. Invention is credited to Masaru Suzuki.
Application Number | 20060195243 11/359620 |
Document ID | / |
Family ID | 36932876 |
Filed Date | 2006-08-31 |
United States Patent
Application |
20060195243 |
Kind Code |
A1 |
Suzuki; Masaru |
August 31, 2006 |
CONTROL DEVICE OF AUTOMATIC TRANSMISSION
Abstract
When a request to switch to a shift to a new third shift step is
made during performing a shift from a first shift step to a second
shift step, a method of performing the shift to the third shift
step is changed according to an engagement pattern of respective
friction engaging components in a steady state of the third shift
step. When there are the friction engaging components that are
continuously being engaged or disengaged at the time of a shift
from the second shift step to the third shift step, the friction
engaging components are continuously engaged or disengaged whereas
the control of engaging or disengaging the other friction engaging
components that are to be changed in the state of engagement or
disengagement is started so as to make the other friction engaging
components respond to the engagement pattern of the third shift
step.
Inventors: |
Suzuki; Masaru; (Anjo-city,
JP) |
Correspondence
Address: |
NIXON & VANDERHYE, PC
901 NORTH GLEBE ROAD, 11TH FLOOR
ARLINGTON
VA
22203
US
|
Assignee: |
DENSO CORPORATION
Kariya-city
JP
|
Family ID: |
36932876 |
Appl. No.: |
11/359620 |
Filed: |
February 23, 2006 |
Current U.S.
Class: |
701/51 ;
701/64 |
Current CPC
Class: |
F16H 61/686 20130101;
F16H 61/0437 20130101; F16H 59/68 20130101; F16H 2306/24 20130101;
F16H 2061/0444 20130101; F16H 2306/14 20130101 |
Class at
Publication: |
701/051 ;
701/064 |
International
Class: |
G06F 17/00 20060101
G06F017/00 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 28, 2005 |
JP |
2005-52264 |
Claims
1. A control device of an automatic transmission, including an
input shaft to which a rotational force is transmitted from a
driving source, a transmission mechanism that varies rotation of
the input shaft and transmits the rotation to an output shaft, and
a plurality of friction engaging components mounted in a plurality
of shift steps of the transmission mechanism, and selectively
switching between engagement and disengagement of the friction
engaging components to switch the shift step of the transmission
mechanism by setting a target shift step according to a request to
switch the shift step and by individually controlling hydraulic
pressures applied to the plurality of friction engaging components,
the control device comprising: multiple shift controlling means
that switches a state of control of the hydraulic pressures applied
to the respective friction engaging components when a request to
switch a shift to a new third shift step is made during performing
a shift from a first shift step to a second shift step to thereby
perform a multiple shift, wherein the multiple shift controlling
means changes a method of performing the shift to the third shift
step according to an engagement pattern which represents a
combination pattern of engagement and disengagement of the
respective friction engaging components in a steady state of the
third shift step.
2. The control device of an automatic transmission, according to
claim 1, wherein when the friction engaging components exist that
are continuously engaged or disengaged at the time of a shift from
the second shift step to the third shift step, the multiple shift
controlling means continues control of engaging or disengaging the
friction engaging components whereas starts control of engaging or
disengaging the other friction engaging components, which are
changed in a state of engagement or disengagement, so as to make
the other friction engaging components respond to the engagement
pattern of the third shift step to thereby move to the shift from
the second shift step to the third shift step..
3. The control device of an automatic transmission, according to
claim 1, wherein when all of the friction engaging components that
are to be switched between engagement and disengagement at the time
of the shift from the first shift step to the second shift step are
different from the friction engaging components that are to be
switched between engagement and disengagement at the time of the
shift from the second shift step to the third shift step, the
multiple shift controlling means continues control of engaging or
disengaging the friction engaging components to achieve an
engagement pattern of the second shift step and at the same time
prepares hydraulic pressures applied to the friction engaging
components relating to the engagement pattern of the third shift
step so as to bring about a state just before being able to achieve
engagement and disengagement of the friction engaging components
before finishing the shift to the second shift step.
4. The control device of an automatic transmission, according to
claims 1, wherein when the engagement pattern of the third shift
step is the same as an engagement pattern of the first shift step,
the multiple shift controlling means disengages the friction
engaging component that is to be switched to being engaged and
engages the friction engaging component that is to be switched to
being disengaged during performing the shift from the first shift
step to the second shift step to thereby cancel the shift to the
second shift step.
5. The control device of an automatic transmission, according to
claim 1, wherein the multiple shift controlling means is provided
with determination means for determining whether or not control of
hydraulic pressures for the respective friction engaging components
that are in process of the multiple shift is allowed.
6. The control device of an automatic transmission, according to
claim 5, wherein when the request to switch to the shift to the
third shift step is detected, the determination means determines
whether or not a first prohibiting condition holds by whether or
not temperature of hydraulic oil of the automatic transmission is
lower than a first previously specified value or by whether or not
a degree of progress in the shift to the second shift step reaches
a specified value, and when the determination means determines that
the first prohibiting condition holds, the multiple shift
controlling means does not perform the shift to the third shift
step and/or does not cancel the shift to the second shift step but
prepares hydraulic pressures applied to the friction engaging
components relating to the engagement pattern of the third shift
step in such a way as to bring about a state just before being able
to achieve engagement and disengagement of the friction engaging
components before finishing the shift to the second shift step.
7. The control device of an automatic transmission, according to
claim 5, wherein when the request to switch to the shift to the
third shift step is detected, the determination means determines
whether or not a second prohibiting condition holds by whether or
not temperature of hydraulic oil of the automatic transmission is
lower than a second specified value that is set at a value lower
than the first specified value, and wherein when the determination
means determines that the second prohibiting condition holds, the
multiple shift controlling means does not perform the shift to the
third shift step until the shift to the second shift step is
finished.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is based on Japanese Patent Application No.
2005-52264 filed on Feb. 28, 2005, the disclosure of which is
incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to a control device of an
automatic transmission provided with the function of performing
multiple shift control when a request to switch to a new shift step
is made during the operation of switching a shift step of an
automatic transmission.
BACKGROUND OF THE INVENTION
[0003] In an automatic transmission for an automobile, the power of
an engine is transmitted to the input shaft of a transmission
mechanism via a torque converter and the rotation of this input
shaft is varied and is transmitted to an output shaft thereof by
this transmission mechanism to rotate and drive a driving wheel. In
the commonest transmission mechanism, a plurality of gears are
arranged between the input shaft and the output shaft to construct
a plurality of power transmission paths of different transmission
gear ratios between the input shaft and the output shaft and
friction engaging components of clutches and brakes are mounted in
the respective power transmission paths. By individually
controlling hydraulic pressures applied to the respective friction
engaging components according to a request to switch a shift step,
the filling control of filling specified friction engaging
components with hydraulic oil and the draining control of draining
the hydraulic oil from specified friction engaging components is
performed to selectively switch between engagement and
disengagement of the respective friction engaging components to
switch the power transmission paths between the input shaft and the
output shaft to thereby switch a transmission gear ratio.
[0004] In this automatic transmission, when a request to switch to
a new shift step is made during the operation of switching a shift
step and a target shift step is changed, the multiple shift control
of switching a shift step of the transmission mechanism to the
target shift step after shift change is performed. For example, the
following case is assumed; the filling control of filling the
cylinder of a clutch or the like with hydraulic oil is being
performed and the filling control is switched in the process of the
filling control to the draining control of draining the hydraulic
oil by the change of a target shift step and then the draining
control is again switched in the process of the draining control to
the filling control by the change of a target shift step. In this
case, depending on a state where the hydraulic oil is drained from
the cylinder by the draining control before shift change, there is
a possibility that when the cylinder is again filled with the
hydraulic oil, the cylinder is excessively filled with the
hydraulic oil to suddenly increase a force for engaging the clutch
to cause a shift shock.
[0005] As a technology for preventing the shift shock caused by
this multiple shift, for example, as disclosed in Japanese Patent
No. 32919790, there is proposed a technology that when a request to
switch to a second shift step is made during the operation of
switching to a first shift step, the operation of switching to the
second shift step is delayed until the operation of switching to
the first shift step is finished.
[0006] However, the operation of switching to the second shift step
is delayed until the operation of switching to the first shift-step
is finished and hence it takes a long time before the operation of
switching to the second shift step is finished.
SUMMARY OF THE INVENTION
[0007] The present invention has been made in consideration of such
circumstances. Therefore, the object of the present invention is to
provide such a control device of an automatic transmission that can
prevent a shift shock caused by a multiple shift and at the same
time can perform a multiple shift with excellent responsivity.
[0008] To achieve the above-mentioned object, the present invention
is such a control device of an automatic transmission that includes
multiple shift controlling means which switches the controlling
state of hydraulic pressure applied to respective friction engaging
components to perform a multiple shift when a request to switch to
a shift to a new third shift step is made during performing a shift
from a first shift step to a second shift step. A method for
shifting to the third shift step is changed according to a
combination pattern of engagement and disengagement (hereinafter
referred to as "engagement pattern") of the respective friction
engaging components in the steady state of the third shift step.
When a request to switch to a shift to a new third shift step is
made during performing a shift from a first shift step to a second
shift step, it is possible to select an appropriate shifting method
and to perform a multiple shift in consideration of the
relationship between the engagement pattern of the respective
friction engaging components at that time. Hence, it is possible to
restrict a shift shock caused by a multiple shift and at the same
time to perform a multiple shift with excellent responsivity.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 is a general schematic construction diagram of an
automatic transmission in one embodiment of the present
invention.
[0010] FIG. 2 is a diagram showing a combination of engagement and
disengagement of clutches C0 to C2 and brakes B0 to B3 for
respective shift steps.
[0011] FIG. 3 is a graph showing one example of a shift
pattern.
[0012] FIG. 4 is a time chart showing a control example (shift
change) when a request to switch a shift to a third speed is made
during performing a shift from a fifth speed to a fourth speed.
[0013] FIG. 5 is a time chart showing a control example (shift
cancellation) when a request to switch a shift to a fifth speed is
made during performing the shift from the fifth speed to the fourth
speed.
[0014] FIG. 6 is a time chart showing a control example (continuous
shift preparation) when a request to switch a shift to a second
speed is made during performing a shift from the fourth speed to
the third speed.
[0015] FIG. 7 is a time chart showing a control example (continuous
shift preparation) when a request to switch a shift to the third
speed is made after a change in the rotational speed of an input
shaft is started during performing the shift from the fifth speed
to the fourth speed.
[0016] FIG. 8 is a flow chart showing the flow of processing of a
routine for controlling a shift.
[0017] FIG. 9 is a flow chart showing the flow of processing of a
routine for setting a target shift step and a shift performance
state.
[0018] FIG. 10 is a flow chart showing the flow of processing of a
routine for determining and setting a multiple shift.
[0019] FIG. 11 is a flow chart showing the flow of processing of a
routine for determining multiple shift allowance.
[0020] FIG. 12 is a flow chart showing the flow of processing of a
routine for determining whether or not a shift change is
allowed.
[0021] FIG. 13 is a flow chart showing the flow of processing of a
routine for determining whether or not shift cancellation is
allowed.
[0022] FIG. 14 is a flow chart showing the flow of processing of a
routine for determining whether or not continuous shift preparation
is allowed.
[0023] FIG. 15 is a flow chart showing the flow of processing of a
routine for controlling hydraulic pressure for a shift.
[0024] FIG. 16 is a flow chart showing the flow of processing of a
routine for controlling the hydraulic pressure of a clutch that is
to be disengaged.
[0025] FIG. 17 is a flow chart showing the flow of processing of a
routine for controlling the hydraulic pressure of a clutch that is
to be engaged.
[0026] FIG. 18 is a flow chart showing the flow of processing of a
routine for controlling hydraulic pressure for a multiple
shift.
[0027] FIG. 19 is a flow chart showing the flow of processing of a
routine for determining whether or not continuous shift preparation
is allowed.
[0028] FIG. 20 is a diagram showing one example of a shift table
for setting a target shift step according to a present shift step
and a requested shift step.
[0029] FIG. 21 is a diagram showing one example of a shift table
for setting a multiple target shift step according to a target
shift step and a requested shift step.
[0030] FIG. 22 is a diagram showing one example of a table for
setting a shift method according to an engagement pattern of a
multiple target shift step from the kind of a shift and a multiple
target shift step.
[0031] FIG. 23 is a flow chart showing the flow of processing of a
routine for setting shift performance.
[0032] FIG. 24 is a flow chart showing the flow of processing of a
routine for setting shift change performance.
[0033] FIG. 25 is a flow chart showing the flow of processing of a
routine for setting shift cancellation performance.
[0034] FIG. 26 is a flow chart showing the flow of processing of a
routine for setting continuous shift preparation performance.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0035] Hereinafter, one embodiment in which the best mode for
carrying out the present invention is applied to a five-speed
automatic transmission to embody the present invention will be
described.
[0036] First, the schematic construction of an automatic
transmission 11 will be described on the basis of FIG. 1. The
output shaft of an engine (driving source) 12 has the input shaft
15 of a torque converter 14 coupled thereto and the output shaft 16
of this torque converter 14 has a hydraulic driving type
transmission gear mechanism (transmission mechanism) 17 coupled
thereto. In the torque converter 14, a pump impeller 18 and a
turbine runner 19, which construct a hydraulic coupling, are
opposed to each other and a stator 20 for straightening the flow of
oil is interposed between the pump impeller 18 and the turbine
runner 19. The pump impeller 18 is coupled to the input shaft 15 of
the torque converter 14 and the turbine runner 19 is coupled to the
output shaft 16 of the torque converter 14.
[0037] Then, the torque converter 14 is provided with a lock-up
clutch 21 for engaging or disengaging the input shaft 15 with or
from the output shaft 16. The engine 12 has its output torque
transmitted to the transmission mechanism 17 via the torque
converter 14 and has its rotation speed varied by first to third
planetary gear mechanisms 22 to 24 of the transmission gear
mechanism 17 and has the output torque transmitted to the driving
wheels (front wheels or rear wheels) of a vehicle.
[0038] The transmission gear mechanism 17 is provided with a
plurality of clutches C0, C1, and C2 and brakes B0, B1, B2, and B3,
which are friction engaging components for switching a plurality of
shifting steps, and a plurality of one-way clutches F0, F1, and F2.
As shown in FIG. 2, by hydraulically engaging and disengaging these
clutches C0, C1, and C2 and brakes B0, B1, B2, and B3, a
combination of gears of the respective planetary gear mechanisms 22
to 24 for transmitting power is switched to thereby switch a
transmission gear ratio.
[0039] FIG. 2 shows a combination of engagement of the clutches C0,
C1, and C2 and the brakes B0, B1, B2, and B3 of the five-speed
automatic transmission and a circular mark shows that the clutch or
the brake is held in an engaging state (in a state where torque is
transmitted) in that transmission step and no mark shows that the
clutch or the brake is held in a disengaging state. For example,
when a downshift from the third speed to the second speed is
performed, one clutch C1 of the clutches C1, C2 and the brakes B1,
B3 which are held in an engaging state at the third speed is
disengaged and the brake B2 is engaged instead to perform a
downshift to the second speed. When an upshift from the third speed
to the fourth speed is performed, one brake B1 of the clutches C1,
C2 and the brakes B1, B3 which are held in an engaging state at the
third speed is disengaged and the clutch C0 is engaged instead to
perform an upshift to the fourth speed.
[0040] As shown in FIG. 1, the transmission gear mechanism 17 is
provided with a hydraulic pump (not shown) driven by the power of
the engine 12 and an oil pan (not shown) for storing hydraulic oil
is provided with a hydraulic control circuit 25. This hydraulic
control circuit 25 is constructed of a line pressure control
circuit 26, an automatic shift control circuit 27, a lock-up
control circuit 28, and a manual switching valve 29. Hydraulic oil
sucked from the oil pan by the hydraulic pump is supplied to the
automatic shift control circuit 27 and the lock-up control circuit
28 via the line pressure control circuit 26. The line pressure
control circuit 26 is provided with a hydraulic control valve (not
shown) for controlling a hydraulic pressure from the oil pump to a
specified line pressure. The automatic shift control circuit 27 is
provided with a plurality of hydraulic control valves (not shown)
for shifting for controlling hydraulic pressures applied to the
respective clutches C0, C1, and C2 and the respective brakes B0,
B1, B2, and B3 of the transmission gear mechanism 17. The lock-up
control circuit 28 is provided with a hydraulic control valve for
lock-up control for controlling a hydraulic pressure applied to the
lock-up clutch 21.
[0041] Moreover, the manual switching valve 29 that is switched in
connection with the operation of a shift lever 30 is interposed
between the line pressure control circuit 26 and the automatic
shift control circuit 27. In a case where the shift lever 30 is
operated in a neutral range (N range) or in a parking range (P
range), even when the passage of current through the hydraulic
control valve of the automatic shift control circuit 27 is stopped
(OFF), the hydraulic pressure applied to the transmission gear
mechanism 17 is switched by the manual switching valve 29 so as to
bring the transmission gear mechanism 17 to a neutral state.
[0042] Meanwhile, the engine 12 is provided with a throttle
position sensor 31 for detecting a throttle position. Then, the
transmission gear mechanism 17 is provided with a rotational speed
sensor 32 for detecting the rotational speed of the sun gear 22a of
a first planetary gear mechanism 22, a rotational speed sensor 33
for detecting the rotational speed of the carrier 22b of the first
planetary gear mechanism 22, and an output shaft rotational speed
sensor 35 for detecting the rotational speed of the output shaft 34
of the transmission gear mechanism 17.
[0043] The output signals of these various sensors are inputted to
an automatic transmission electronic control unit (hereinafter
referred to as "AT-ECU") 36. This AT-ECU 36 is mainly constructed
of a microcomputer and performs various programs for shift control
stored in a built-in ROM (storage medium) to vary the speed of the
transmission gear mechanism 17 according to a previously set shift
pattern as shown in FIG. 3. That is, the AT-ECU 36 controls the
passage of current through the respective hydraulic control valves
of the automatic shift control circuit 27 according to a shift step
switching request (request to switch a target shift step) made
according to the operating position of the shift lever 30 and
driving conditions (throttle position, vehicle speed, and the like)
to thereby control hydraulic pressures applied to the respective
clutches C0, C1, and C2 and the respective brakes B0, B1, B2, and
B3 of the transmission gear mechanism 17. With this, as shown in
FIG. 2, the switching between engagement and disengagement of the
respective clutches C0, C1, and C2 and the respective brakes B0,
B1, B2, and B3 is done to switch the combination of gears of the
respective planetary gear mechanisms 22 to 24 for transmitting
power, whereby the transmission gear ratio of the transmission gear
mechanism 17 is switched. When a request to switch to a new shift
step is made during switching the shift step of the transmission
gear mechanism 17 and a requested shift step is switched to a new
target shift step, the AT-ECU 36 performs the multiple shift
control of switching the shift step of the transmission gear
mechanism 17 to the new target shift step.
[0044] In the multiple shift control of this embodiment, when a
request to switch to a shift to a new third shift step is made
during performing a shift from a first shift step to a second shift
step, a method for shifting to the third shift step is changed in
the following manner according to the combination pattern of
engagement and disengagement (hereinafter referred to as
"engagement pattern") of the respective friction engaging
components (the respective clutches C0, C1, and C2 and the
respective brakes B0, B1, B2, and B3) in the steady state of the
third shift step. [0045] (1) When there are the friction engaging
components that are continuously engaged or disengaged at the time
of a shift from the second shift step to the third shift step (for
example, when a request to switch to a shift to the third speed
during performing a shift from the fifth speed to the fourth speed,
or when a request to switch to a shift to the second speed during
performing a shift from the fourth speed to the third speed), the
control of engaging or disengaging the friction engaging components
is continued, whereas the control of engaging or disengaging the
other friction engaging components, which are to be changed in the
state of engagement or disengagement, is started so as to make the
other friction engaging components respond to the engagement
pattern of the third shift step to thereby move to the shift from
the second shift step to the third shift step. [0046] (2) When all
of the friction engaging components that are to be switched between
engagement and disengagement at the time of the shift from the
first shift step to the second shift step are different from the
friction engaging components that are to be switched between
engagement and disengagement at the time of the shift from the
second shift step to the third shift step (for example, a request
to switch to a shift to the second speed during performing a shift
from the fourth speed to the third speed), the control of engaging
or disengaging the friction engaging components to achieve an
engagement pattern of the second shift step is continued and at the
same time the applying of hydraulic pressures to the friction
engaging components relating to the engagement pattern of the third
shift step is prepared so as to bring about a state just before
being able to achieve the engagement and disengagement of the
friction engaging components before finishing the shift to the
second shift step. [0047] (3) When the engagement pattern of the
third shift step is the same as the engagement pattern of the first
shift step (for example, a request to switch to a shift to the
fifth speed during performing a shift from the fifth speed to the
fourth speed), the friction engaging component that is to be
switched to being engaged is disengaged and the friction engaging
component that is to be switched to being disengaged is engaged
during performing the shift from the first shift step to the second
shift step to thereby cancel the above-mentioned shift to the
second shift step. [0048] (4) As the temperature of hydraulic oil
becomes lower, the fluidity of the hydraulic oil becomes lower and
hence the responsivity of hydraulic control becomes lower and hence
progress in shifting to the respective steps becomes slower.
Therefore, when the temperature of the hydraulic oil becomes too
low, there is a possibility that the responsivity of hydraulic
control is not sufficient for performing the above-mentioned
multiple shift control. When a change in the rotational speed of
the input shaft to the second shift step is already started at the
time when a request to switch to the shift to the third shift step
is made, it is difficult to perform the above-mentioned multiple
shift control.
[0049] Hence, when the request to switch to the shift to the third
shift step is detected, it is determined whether or not a first
prohibiting condition holds by whether or not the temperature of
the hydraulic oil of the automatic transmission is lower than a
first previously specified value or by whether or not the degree of
progress in the shift to the second shift step reaches a specified
value. When it is determined that the first prohibiting condition
holds, the shift to the third shift step, which has been described
in (1), is not performed and/or the canceling of the shift to the
second shift step, which has been described in (3), is not
performed, but the applying of hydraulic pressures to the friction
engaging components relating to the engagement pattern of the third
shift step is prepared so as to bring about a state just before
being able to achieve the engagement and disengagement of the
friction engaging components before finishing the shift to the
second shift step. (5) When the request to switch to the shift to
the third shift step is detected, it is determined whether or not a
second prohibiting condition holds by whether or not the
temperature of the hydraulic oil of the automatic transmission is
lower than a second specified value that is set at a value lower
than the first specified value. When it is determined that the
second prohibiting condition holds, the shift to the third shift
step is not performed until the shift to the second shift step is
finished (in other words, the shift to the third shift step is
performed after the shift to the second shift step is
finished).
[0050] Next, specific examples of the multiple shift control of the
present embodiment will be described by the use of a time chart
shown in FIG. 4 to FIG. 7.
[0051] FIG. 4 is a time chart showing a control example (shift
change) when a request to switch to a shift to the third speed is
made during performing a shift from the fifth speed to the fourth
speed. As shown in the engagement table in FIG. 2, when the shift
from the fifth speed to the fourth speed is performed, the clutches
C0, C1 and the brake B3 are continuously engaged and the brakes B0,
B2 are continuously disengaged, whereas the clutch C2 is switched
from being disengaged to being engaged and the brake B1 is switched
from being engaged to being disengaged. Meanwhile, when a shift
from the fifth speed to the third speed is performed, the clutch C1
and the brakes B1, B3 are continuously engaged and the brakes B0,
B2 are continuously disengaged, whereas the clutch C2 is switched
from being disengaged to being engaged and the clutch C0 is
switched from being engaged to being disengaged. Hence, when the
request to switch to the shift to the third speed is made during
performing the shift from the fifth speed to the fourth speed, the
control of engaging the clutch C2 is continued and the control of
disengaging the brake B1 is stopped, but the control of disengaging
the clutch C0 is started instead. With this, the shift change of
shifting from the fifth speed to the third speed is performed to
perform a shift to the third speed which is a requested shift step
(third shift step).
[0052] FIG. 5 is a time chart showing a control example (shift
cancellation) when a request to switch to a shift to the fifth
speed is made during performing the shift from the fifth speed to
the fourth speed. In this case, because the third shift step (fifth
speed) is the same as the first shift step (fifth speed), during
performing the shift to the fourth speed, the clutch C2 that is a
friction engaging component that is to be switched to being engaged
is disengaged and the brake B1 that is a friction engaging
component that is to be switched to being disengaged is engaged.
With this operation, the shift to the fourth speed, which is the
second shift step, is cancelled and the shift to the fifth speed,
which is the requested shift step (third shift step), is
performed.
[0053] FIG. 6 is a time chart showing a control example (continuous
shift preparation) when a request to switch to a shift to the
second speed is made during performing a shift from the fourth
speed to the third speed. When the shift from the fourth speed to
the third speed is performed, as shown in the engagement table in
FIG. 2, the clutches C1, C2 and the brake B3 are continuously
engaged and the brakes B0, B2 are continuously disengaged, whereas
the clutch C0 is switched from being disengaged to being engaged
and the brake B1 is switched from being engaged to being
disengaged. Meanwhile, when a shift from the third speed to the
second speed is performed, the clutch C2 and the brakes B1, B3 are
continuously engaged and the clutch C0 and the brake 15 B0 are
continuously disengaged, whereas the brake B2 is switched from
being disengaged to being engaged and the clutch C1 is switched
from being engaged to being disengaged. Hence, when the request to
switch to the shift to the second speed is made during performing
the shift from the fourth speed to the third speed, different
clutches and brakes are controlled between the shift from the
fourth speed to the third speed and the shift from the third speed
to the second speed. Therefore, when the request to switch to the
shift to the second speed is made during performing the shift from
the fourth speed to the third speed, to continuously perform the
shift from the third speed to the second speed while performing the
shift from the fourth speed to the third speed, the preparation
control of engaging the brake B2 and disengaging the clutch C1
(control of preparing hydraulic pressures applied to the brake B2
and the clutch C1 so as to bring about a state just before being
able to achieve engagement and disengagement) is performed and
waits until the shift from the fourth speed to the third speed is
finished. Then, immediately after the shift from the fourth speed
to the third speed is finished, the hydraulic control of the brake
B2 and the clutch C1 is performed to thereby perform a shift to the
second speed which the requested shift step (third shift step).
[0054] FIG. 7 is a time chart showing a control example (continuous
shift preparation) when a request to switch to a shift to the third
speed is made after a change in the rotational speed of the input
shaft is started during performing the shift from the fifth speed
to the forth speed. After the control of the shift from the fifth
speed to the fourth speed is started and then a change in the
rotational speed of the input shaft is started, a change in the
rotation of the input shaft is controlled by a component that is to
be disengaged and hence it is difficult to make a shift change to
shift from the fifth speed to the third speed as shown in FIG. 4.
Hence, in this case, the shift from the fifth speed to the fourth
speed is continued and preparation for performing a shift from the
fourth speed to the third speed in succession is performed. That
is, the following case is assumed; the request to switch to the
shift to the third speed is made after the change in the rotation
of the input shaft is started while the control of engaging the
clutch C2 and disengaging the brake B1 is performed so as to
perform the shift from the fifth speed to the fourth speed. In this
case, the control of the shift from the fifth speed to the fourth
speed is continued and at the same time the preparation of
disengaging the clutch C0 as the preparation of the shift from the
fourth speed to the third speed (control of preparing a hydraulic
pressure applied to the clutch C0 so as to bring about a state just
before disengaging the clutch C0) is performed and then waits until
the shift from the fifth speed to the fourth speed is finished.
Then, immediately after the shift from the fifth speed to the
fourth speed is finished, the control proceeds to the shift from
the fourth speed to the third speed to engage the brake B1.
However, this brake B1 is subjected to the disengaging control in
the shift from the fifth speed to the fourth speed and hence the
preparation of engaging the brake B1 is not performed during
performing the shift from the fifth speed to the fourth speed. When
the control proceeds to the shift from the fourth speed to the
third speed after the shift from the fifth speed to the fourth
speed is finished, the control of engaging the brake B1 and the
control of disengaging the clutch C0 are performed to perform a
shift to the third speed which is the requested shift step (third
shift step).
[0055] The multiple shift control of the present embodiment
described above is performed by the AT-ECU (multiple shift control
means) 36 according to the respective routines shown in FIG. 8 to
FIG. 27. Hereinafter, the processing contents of the respective
routines will be described.
[Routine for Controlling a Shift]
[0056] A routine for controlling a shift, which is shown in FIG. 8,
is performed at specified periods during the operation of the
engine and functions as a main routine for controlling the whole
operation of shifting. When this routine is started, first, a
requested shift step is set in Step S101 according to the operating
position of the shift lever 30 and operating conditions (throttle
position, vehicle speed, and the like) in accordance with the shift
pattern shown in FIG. 3. Then, the routine proceeds to Step S102
where a routine for setting a target shift step and a shift
performance state, which will be described in FIG. 9, is performed
to set a target shift step and a shift performance state. Then, the
routine proceeds to Step S103 where shift hydraulic control is
performed.
[Routine for Setting a Target Shift Step and a Shift Performance
State]
[0057] The routine for setting a target shift step and a shift
performance state, which is shown in FIG. 9, is a sub-routine
started in Step S102 of the routine for controlling a shift, shown
in FIG. 8. When this routine is started, first, it is determined in
Step S201 whether or not a flag for denoting that a shift is in
progress (hereinafter referred to as "in-shift flag") is not ON.
When it is determined that the in-shift flag is not ON, it is
determined that shifting is not being performed and the routine
proceeds to Step S202 where it is determined whether or not a
present shift step agrees with the requested shift step. When the
present shift step agrees with the requested shift step, it is
determined that a request to change a shift step is not made and
the routine proceeds to Step S207 where the in-shift flag is reset
(OFF) and this routine is finished.
[0058] In contrast to this, when it is determined in Step S202 that
the present shift step does not agree with the requested shift
step, the routine proceeds to Step S204 where a target shift step
is set according to a shift table shown in FIG. 20 from the present
shift step and the requested shift step. The shift table shown in
FIG. 20 is set so as to control a shift change with stability by
always performing the hydraulic control of changing a shift range
by the use of a transmission gear mechanism including one engaged
clutch and one disengaged clutch or either or them in such a kind
of shift that limits a discrete shift. For example, in a case where
a request to switch to the second speed is made when the present
shift step is the fifth speed, when a shift from the fifth speed to
the second speed is performed in one stroke according to the
engagement table shown in FIG. 2, it is necessary to disengage the
clutches C0, C1 and to engage the clutch C2 and the brake B2, that
is, to control four friction engaging components. However,
according to the shift table shown in FIG. 20, when a shift from
the fifth speed to the second speed is performed, by setting a
target shift step at the third speed, a shift from the fifth speed
to the third speed in which the clutch C0 is disengaged and the
clutch C2 is engaged is performed and then a shift from the third
speed to the second speed in which the clutch C1 is disengaged and
the brake B2 is engaged is performed. In this manner, a shift from
the fifth speed to the second speed is finally performed.
[0059] Then, the routine proceeds to Step S205 where a routine for
setting shift performance, which will be described later shown in
FIG. 23, is performed to set the kind of a shift to be performed
from the present shift step and the target shift step set in Step
S204 to set friction engaging components that are to be disengaged
or engaged. Describing the detail, as shown in FIG. 2, for example,
when the present shift step is the fifth speed and the target shift
step is the third speed, the kind of a shift to be performed is a
shift from the fifth speed to the third speed and a friction
engaging component that is to be disengaged is the clutch C0 and a
friction engaging component that is to be engaged is the clutch C2.
Thereafter, the routine proceeds to Step S208 where the in-shift
flag is set (ON) and the present routine is finished.
[0060] Meanwhile, when it is determined in Step S201 that the
in-shift flag is ON, it is determined that a shift is in progress
and the routine proceeds to Step S203 where it is determined
whether or not a requested shift step is different from the target
shift step. When the requested shift step agrees with the target
shift step, the routine proceeds to Step S208 where the in-shift
flag is set (ON) and the present routine is finished. In contrast
to this, when it is determined in Step S203 that the requested
shift step is different from the target shift step, the routine
proceeds to Step S206 where a routine for determining and setting a
multiple shift, which will be described later shown in FIG. 10, is
performed and then the routine proceeds to Step S208 where the
in-shift flag is set (ON) and the present routine is finished.
[0061] The description of the flow of processing of the
above-mentioned routine for setting a target shift step and a shift
performance state shown in FIG. 9 from the viewpoint of the state
of a shift is as follows. [0062] (1) When a shift is not in
progress, Step 201, Step 202, and Step 207 are performed in this
series. [0063] (2) When a shift is started, Step 201, Step 202,
Step 204, Step 205, and Step 208 are performed in this series.
[0064] (3) When a shift is in progress, Steps 201, Step 203, and
Step 208 are performed in this series. [0065] (4) When a multiple
shift is determined, Steps 201, Step 203, Step 206, and Step 208
are performed in this series. [Routine for Determining and Setting
a Multiple Shift]
[0066] A routine for determining and setting a multiple shift,
which is shown in FIG. 10, is a sub-routine started in Step S206 of
the above-mentioned routine for setting a target shift step and a
shift performance state, which is shown in FIG. 9. When this
routine is started, first, a routine for determining whether or not
a multiple shift is allowed, which will be described later in FIG.
11, is performed in Step S301 to determine whether or not a
multiple shift is allowed. Thereafter, the routine proceeds to Step
S302 and when it is determined on the basis of the determination
result in Step S301 that a multiple shift is not allowed, the
present routine is finished without performing the subsequent
processing. Here, when a multiple shift is not allowed, a new shift
request is not received during performing the shift but a multiple
shift is not performed.
[0067] In contrast to this, when it is determined in Step S302 that
a multiple shift is allowed, the routine proceeds to Step S303
where a multiple target shift step is set from the target shift
step and the requested shift step according to a shift table shown
in FIG. 21, just as with the setting processing in Step S204 shown
in FIG. 9. Then, the routine proceeds to Step S304 where a routine
for determining whether or not a shift change is allowed, which
will be described later in FIG. 12, is performed to determine
whether or not a shift change is allowed.
[0068] Thereafter, the routine proceeds to Step S305 where it is
determined on the basis of the determination result in Step S304
whether or not a shift change is allowed. Then, when it is
determined that a shift change is allowed, the routine proceeds to
Step S307 where a routine for setting shift change performance,
which will be described later in FIG. 24, is performed to change
the kind of a shift to be performed and friction engaging
components that are to be disengaged or engaged as settings for
performing the shift change. Settings for friction engaging
components, which are to be completely engaged or disengaged by the
shift change, are changed so as to perform multiple shift hydraulic
control. This is shown in detail in FIG. 4.
[0069] For example, when a multiple target shift step is changed to
the third speed during performing a shift from the fifth speed to
the fourth speed, the kind of a shift to be performed is changed
from a shift from the fifth speed to the third speed and settings
are changed in such a way that the clutch C2 is engaged
(continuously engaged) and that the clutch C0 is disengaged.
Settings are changed in such a way that pressure increasing control
is performed to the brake B1, to which disengaging control is
performed at the time of performing the shift from the fifth speed
to the fourth speed, so as to completely engage the brake B1 in
place of the clutch C0. That is, by changing settings in this
manner, in shift hydraulic control that will be described later,
the control of engaging the clutch C2 is continued whereas the
control of disengaging the brake B1 is stopped and the control of
increasing hydraulic pressure for the brake B1 at the time of a
shift change is performed, and the hydraulic control of disengaging
the clutch C0 in place of the brake B1 is performed. With this, a
shift change to the shift from the fifth speed to the third speed
is performed.
[0070] Meanwhile, when it is determined in Step S305 that a shift
change is not allowed, the routine proceeds to Step S306 where a
routine for determining whether or not shift cancellation, which
will be described later in FIG. 13, is allowed is performed to
determine whether or not shift cancellation is allowed. Thereafter,
the routine proceeds to Step S308 where it is determined on the
basis of determination result in Step S306 whether or not shift
cancellation is allowed. When shift cancellation is allowed, the
routine proceeds to Step S310 where settings are changed so as to
perform the shift cancellation in such a way that the hydraulic
control of engaging or disengaging the friction engaging components
in the kind of a shift in the process of being performed is stopped
and that the control of increasing hydraulic pressure for the
friction engaging components that are to be engaged in the shift
cancellation and of decreasing hydraulic pressure for the friction
engaging components that are to be disengaged in the shift
cancellation is performed. This processing is shown in detail in
FIG. 5. For example, when a multiple target shift step is set at
the fifth speed during performing a shift from the fifth speed to
the fourth speed, settings-are changed in such a way that the
control of disengaging the brake B1 during performing the shift
from the fifth speed to the fourth speed is changed to the control
of increasing hydraulic pressure for brake B1 at the time of the
shift cancellation so as to completely engage the brake B1 and that
the control of engaging the clutch C2 during performing the shift
from the fifth speed to the fourth speed is changed to the control
of decreasing hydraulic pressure for clutch C2 so as to disengage
the clutch C2 at the time of the shift cancellation. With this
setting change, the control of canceling a shift is performed in
the shift hydraulic control that will be described later.
[0071] In contrast to this, when it is determined in Step S306 that
shift cancellation is not allowed, the routine proceeds to Step
S309 where a routine for determining whether or not continuous
shift preparation, which will be described later in FIG. 14, is
allowed to determine whether or not continuous shift preparation is
allowed. Thereafter, the routine proceeds to Step S311 where it is
determined whether or not it is determined in Step S309 that
continuous shift preparation is allowed. When it is determined in
Step S309 that continuous shift preparation is allowed, the routine
proceeds to Step S312 where friction engaging components for which
continuous shift preparation is to be performed are set as the
setting of performing continuous shift preparation. This processing
is shown in detail in FIG. 6. For example, when a multiple target
shift step is set at the second speed during performing a shift
from the fourth speed to the third speed, the control of
disengaging the clutch C0 and the control of engaging the brake B1
for the purpose of performing the shift from the fourth speed to
the third speed are continued so as to perform the shift from the
fourth speed to the third speed. At the same time, for the purpose
of performing such a shift from the third speed to the second speed
that is to be continuously performed next in succession, settings
are made in such a way that the control of hydraulic pressure for
disengaging and holding the clutch C1 is performed at the time of
the continuous shift preparation and that the control of hydraulic
pressure for engaging the brake B2 is performed at the time of the
continuous shift preparation. With this setting, the control of
continuous shift preparation is performed in the shift hydraulic
control that will be described later.
[0072] When it is determined in Step S311 that continuous shift
preparation is not allowed, the present routine is finished without
performing any processing. In this case, the multiple shifts are
not performed.
[Routine for Determining Whether or Not Multiple Shifts are
Allowed]
[0073] A routine for determining whether or not a multiple shift is
allowed, which is shown in FIG. 11, is a sub-routine started in
Step S301 in the routine for determining and setting a multiple
shift, which is shown in FIG. 10, and acts as determination means.
When this routine is started, first, it is determined in Step S401
whether or not an oil temperature is lower than a second specified
value. When the oil temperature is not lower than the second
specified value, the routine proceeds to Step S402 where the
setting of allowing a multiple shift is performed. When the oil
temperature is lower than the second specified value, it is
determined that a second prohibiting condition holds and the
present routine is finished without performing the setting of
allowing a multiple shift. The threshold (second specified value)
of the oil temperature used for determination in the Step S401 is
set at a value lower than the threshold of the oil temperature
(first specified value) used for determination in Step S404 of the
routine for determining whether or not a shift change is allowed,
which will be described later in FIG. 12.
[Routine for Determining Whether or Not Shift Change is
Allowed]
[0074] The routine for determining whether or not a shift change is
allowed, which is shown in FIG. 12, is a sub-routine started in
Step S304 of the routine for determining and setting a multiple
shift, which is shown in FIG. 10, and acts as determination means.
When this routine is started, first, in Step S403, on the basis of
the table in FIG. 22 from the multiple target shift step determined
in Step S303 shown in FIG. 10 and the kind of a shift in the
process of being performed, it is determined whether or not a shift
change can be performed. The table shown in FIG. 22 is a table for
setting a shift method according to the engagement pattern of a
multiple target shift step determined from the kind of a shift,
which is set from the present shift step and the target shift step,
and the multiple target shift step.
[0075] For example, when a multiple target shift step (third shift
step) is set at the third speed during performing a shift from the
fifth speed to the fourth speed, a shift to the third speed from a
state, in which the brake B1 is disengaged and the clutch C2 is
engaged at the time of performing the shift from the fifth speed to
the fourth speed, can be performed by continuing engaging the
clutch C2 and by disengaging the clutch C0 in place of disengaging
the brake B1. Hence, it is set in the table in FIG. 22 that this
shift change is allowed.
[0076] Moreover, when a multiple target shift step is set at the
fifth speed during performing the shift from the fifth speed to the
fourth speed, the multiple target shift step is the same as the
present shift step and hence it is set that a shift to the fourth
speed can be cancelled. Even when a request to switch to a shift to
the first speed or the second speed is made during performing the
shift from the fifth speed to the fourth speed, a shift method of
performing the shift to the first speed or the second speed during
performing the shift from the fifth speed to the fourth speed is
not set because the multiple target shift step is set at the third
speed in Step S303 shown in FIG. 10.
[0077] Furthermore, when a multiple target shift step is set at the
second speed during performing a shift from the fourth speed to the
third speed, in order to perform a shift to the second speed from a
state where the clutch C0 is disengaged and the brake B1 is engaged
to perform the shift from the fourth speed to the third speed, it
is further necessary to disengage the clutch C1 and to engage the
brake B2. In this case, different friction engaging components are
disengaged and engaged so as to perform the shift to the second
speed during performing the shift from the fourth speed to the
third speed and hence it is set that continuous shift preparation
is allowed. In this manner, a method for performing a multiple
shift is previously compiled and set for all of the kinds of shifts
and the multiple target shift steps.
[0078] When it is determined in Step S403 that a multiple target
shift step cannot be changed, the present routine is finished
without performing the setting of allowing a shift change. When it
is determined in Step S403 that a multiple target shift step can be
changed, the routine proceeds to Step S404 where it is determined
whether or not a shift change is allowed by whether or not the oil
temperature is lower than the first specified value or by whether
or not the degree of progress in the shift (gear ratio) is smaller
than a specified value. The determination threshold (first
specified value) of the oil temperature used for determination in
this Step S404 is set at a value higher than the determination
threshold (second specified value) of the oil temperature for
determination in Step S301 shown in FIG. 10.
[0079] When determination result in this Step S404 is NO, the
routine proceeds to Step S405 where the setting of allowing a shift
change is performed. When determination result in this Step S404 is
YES, it is determined that the first prohibiting condition holds
and the present routine is finished without performing the setting
of allowing a shift change.
[Routine for Determining Whether or Not Shift Cancellation is
Allowed]
[0080] A routine for determining whether or not shift cancellation
is allowed, which is shown in FIG. 13, is a sub-routine started in
Step S306 of the routine for determining and setting a multiple
shift and acts as determination means. When this routine is
started, first, in Step S406, just as with the determination of
whether or not a shift change is allowed, which is performed in
Step S304 shown in FIG. 10, it is determined on the basis of the
table shown in FIG. 22 from the multiple target shift step
determined in Step S303 shown in FIG. 10 and the kind of a shift in
the process of being now performed, whether or not shift
cancellation is allowed. When it is determined that shift
cancellation can be performed, the routine proceeds to Step S407
where it is determined whether or not the shift cancellation is
allowed by whether or not the oil temperature or the degree of
progress in the shift (gear ratio) is lower than a specified
value.
[0081] When determination result in this Step S407 is NO, the
routine proceeds to Step S408 where the setting of allowing shift
cancellation is performed. In contrast to this, when determination
result in this Step S406 is NO or when determination result in this
Step S407 is YES, the present routine is finished without
performing the setting of allowing shift cancellation.
[Routine for Determining Whether or Not Continuous Shift
Preparation is Allowed]
[0082] A routine for determining whether or not continuous shift
preparation is allowed is a sub-routine started in Step S309 of the
routine for determining and setting a multiple shift, which is
shown in FIG. 10. When this routine is started, first, in Step
S409, it is determined on the basis of the table shown in FIG. 22
from the multiple target shift step determined in Step S303 shown
in FIG. 10 and the kind of a shift in the process of being now
performed, whether or not continuous shift preparation is allowed.
When it is determined that continuous shift preparation is allowed,
the routine proceeds to Step S410 where the setting of allowing the
continuous shift preparation is performed. When it is determined in
Step S409 that continuous shift preparation is not allowed, the
present routine is finished without performing the setting of
allowing continuous shift preparation.
[Routine for Controlling Hydraulic Pressure for shift]
[0083] A routine for controlling hydraulic pressure for a shift is
a sub-routine started in Step S103 of the routine for controlling a
shift, which is shown in FIG. 8. When this routine is started,
first, it is determined in Step S501 whether or not the in-shift
flag is set (ON) (the shift is now in process). When it is
determined that in-shift flag is not set ON, it is determined that
a shift is not in process and the present routine is finished
without performing the subsequent processing.
[0084] In contrast to this, when it is determined that in-shift
flag is set (ON) (the shift is now in process), the routine
proceeds to Step S502 where a routine for controlling hydraulic
pressure for a clutch that is to be disengaged, which will be
described later in FIG. 16, is performed. Then, the routine
proceeds to Step S503 where a routine for controlling hydraulic
pressure for a clutch that is to be engaged, which will be
described later in FIG. 17, is performed. Then, the routine
proceeds to the next Step S504 whether or not a multiple shift is
in process when it is determined that a multiple shift is in
process, the routine proceeds to Step S505 where a routine for
controlling hydraulic pressure for a multiple shift, which will be
described later in FIG. 18, is performed.
[0085] Thereafter, the routine proceeds to Step S506 where it is
determined whether or not shift is finished when it is determined
that shift is being performed, the present routine is finished
without performing anything. When it is determined that shift is
finished, the routine proceeds to Step S507 where the processing of
finishing shift is performed.
[Routine for Controlling Hydraulic Pressure for Clutch that is to
be Disengaged]
[0086] A routine for controlling hydraulic pressure for a clutch
that is to be disengaged is a sub-routine started in Step S502 of
the routine for controlling hydraulic pressure for a shift, which
is described in FIG. 15. When the present routine is started,
first, it is determined in Step S600 whether or not there is a
clutch that is to be disengaged (including also a brake that is to
be disengaged, ditto for the following), which is switched from
being engaged to being disengaged. When it is determined in Step
S600 that there is not a clutch that is to be disengaged, the
present routine is finished without performing any processing.
[0087] In contrast to this, when it is determined in Step S600 that
there is a clutch that is to be disengaged, the routine proceeds to
Step S601 where the present step of the control of hydraulic
pressure for a clutch that is to be disengaged is determined by
whether or not the value of a control step flag FlagRL of a clutch
that is to be disengaged is any one of 0 to 4. This control step
flag FlagRL is a flag, which is incremented by one every time the
step of the control of hydraulic pressure for a clutch that is to
be disengaged advances, and has an initial value 0 and a maximum
value of 4. Hence, the control of hydraulic pressure for a clutch
that is to be disengaged is a sequence control of four steps.
[0088] When the control of hydraulic pressure for a clutch that is
to be disengaged is started, the control step flag FlagRL is set at
an initial value (0) and hence the routine proceeds to Step S602
where the command value of hydraulic pressure for a clutch that is
to be disengaged is set at an initial hydraulic pressure and where
hydraulic pressure applied to the clutch that is to be disengaged
is decreased to an initial hydraulic pressure. Then, the routine
proceeds to Step S603 where the control step flag FlagRL is set at
"1" (first step control) and then the present routine is
finished.
[0089] When the present routine is started next time, because the
control step flag FlagRL is already set at "1," the routine
proceeds to Step S604 where the pressure decreasing control of
decreasing the command value of hydraulic pressure for a clutch
that is to be disengaged gently at a specified gradient (second
step control) is performed. With this, the force of engaging the
clutch that is to be disengaged is decreased to cause the capacity
of transmission torque of the clutch that is to be disengaged to be
smaller than torque inputted from the engine, whereby the
rotational speed of the input shaft of the transmission gear
mechanism 17 (rotational speed of the output shaft 16 of the torque
converter 14) starts to increase rapidly.
[0090] This pressure decreasing control of the clutch that is to be
disengaged (second step control) is continued until a rapid
increase in the rotational speed of the input shaft is detected
(Step S605). Then, when the rapid increase in the rotational speed
of the input shaft is detected, the routine proceeds to Step S606
where the control step flag FlagRL is set at "2" and this second
step control (pressure decreasing control) is finished and the
routine proceeds to a third step control.
[0091] In this third step control, first, in Step S607, hydraulic
pressure for the clutch that is to be disengaged is fed back in
such a way that a gradient of the rapid increase in the rotational
speed of the input shaft becomes a specified value. In the process
of this feedback control, it is determined in Step S608 whether or
not the degree of progress in the shift (degree of an increase in
the rotational speed of the input shaft) is close to a specified
value when the shift is finished. When the degree of progress in
the shift is not close to the specified value when the shift is
finished, the feedback control is continued. Thereafter, when the
degree of progress in the shift is close to the specified value
when the shift is finished, the routine proceeds to Step S609 where
the control step flag FlagRL is set at "3" and the third step
control (feedback control) is finished and the routine proceeds to
a fourth step control.
[0092] In this fourth step control, first, in Step S610, the final
pressure decreasing control of decreasing the command value of
hydraulic pressure for the clutch that is to be disengaged to "0"
at a specified gradient is performed. Then, in the next Step S611,
it is determined whether or not the command value of hydraulic
pressure for the clutch that is to be disengaged is decreased to a
value not larger than "0" and this fourth step control (final
pressure decreasing control) is continued until the command value
of hydraulic pressure for the clutch that is to be disengaged is
decreased to the value not larger than "0." Thereafter, when the
command value of hydraulic pressure for the clutch that is to be
disengaged is decreased to the value not larger than "0," the
routine proceeds to Step S612 where the control step flag FlagRL is
set at "4" and this fourth step control is finished. With this, the
control of hydraulic pressure for a clutch that is to be disengaged
is completely finished.
[Routine for Controlling Hydraulic Pressure for Clutch that is to
be Engaged]
[0093] A routine for controlling hydraulic pressure for a clutch
that is to be engaged, which is shown in FIG. 17, is a sub-routine
started in Step S503 of the routine for controlling hydraulic
pressure for a shift, which is shown in FIG. 15, and is started at
the same time when the control of hydraulic pressure for a clutch
that is to be disengaged is started. When this routine is started,
first, it is determined in Step S700 whether or not there is a
clutch that is to be engaged, which is to be switched from being
disengaged to being engaged (including a brake that is to be
engaged, ditto for the following). When it is determined that there
is not a clutch that is to be engaged, the present routine is
finished without performing any processing.
[0094] In contrast to this, when it is determined that there is a
clutch that is to be engaged, the routine proceeds to Step S701
where the present step of the control for hydraulic pressure for a
clutch that is to be engaged is determined by whether or not the
control step flag FlagAP of the clutch that is to be engaged is any
one of 0 to 5. This control step flag FlagAP is a flag, which is
incremented by one every time the step of the control of hydraulic
pressure for a clutch that is to be engaged advances, and has an
initial value of 0 and a maximum value of 5. Hence, the control of
hydraulic pressure for a clutch that is to be engaged is a sequence
control of five steps.
[0095] When the control of hydraulic pressure for a clutch that is
to be engaged is started, the control step flag FlagAP is set at an
initial value of "0." Hence, the routine proceeds to Step S702
where the command value of hydraulic pressure for the clutch that
is to be engaged is set at a specified filling hydraulic pressure
in such a way as to bring the clutch that is to be engaged to a
state just before developing an engaging force and then the filling
control of filling the clutch that is to be engaged with hydraulic
oil is performed. Then, the routine proceeds to the next Step S703
where the control step flag FlagAP is set at "1" and then the
present routine is finished.
[0096] When the present routine is started next time, because the
control step flag FlagAP is already set at "1," the routine
proceeds to Step S704 where filling hydraulic pressure is held and
the routine proceeds to the next Step S705 where it is determined
whether or not a specified time passes. Here, the specified time is
a standard (average) time required for the clutch that is to be
engaged to be brought by the filling control to a state just before
developing an engaging force and is previously set by experiment,
simulation, or the like.
[0097] Thereafter, when a filling control time reaches a specified
time (when the clutch that is to be engaged is brought by the
filling control to a state just before developing an engaging
force), the routine proceeds from Step S705 to Step S706 where the
control step flag FlagAP is set at "2" and the command value of
hydraulic pressure for the clutch that is to be engaged is
decreased to a standby hydraulic pressure and the filling control
is finished. Thereafter, the clutch that is to be engaged is held
by this standby hydraulic pressure in the state just before
developing an engaging force.
[0098] Because the control step flag FlagAP is set at "2" for a
period during which this standby hydraulic pressure is held, the
routine proceeds from Step S707 to Step S708 where it is determined
whether or not the degree of progress in the shift (degree of an
increase in the rotational speed of the input shaft) advances to a
specified step. When it is determined that the degree of progress
in the shift advances to the specified step, the command value of
hydraulic pressure for the clutch that is to be engaged is held at
the standby hydraulic pressure. Thereafter, when it is determined
that the degree of shift does not advance to a specified step, the
routine proceeds from Step S708 to Step S709 where the control step
flag FlagAP is set at "3" and the routine proceeds to the next Step
S710 where the pressure increasing control of increasing the
command value of hydraulic pressure for the clutch that is to be
engaged gently at a specified gradient is started.
[0099] Thereafter, when the present routine is started, because the
control step flag FlagAP is already set at "3," the routine
proceeds to Step S710 where the pressure increasing control of
increasing the command value of hydraulic pressure for the clutch
that is to be engaged gently at the specified gradient is
continued. Then, the routine proceeds to the next Step S711 where
it is determined whether or not the control step flag FlagRL of the
clutch that is to be disengaged is set at "4" (in other words,
whether or not the control step of the clutch that is to be
disengaged advances to the final pressure decreasing control). When
the control step flag FlagRL of the clutch that is to be disengaged
is not set at "4," the present routine is finished without
performing any processing and the pressure increasing control of
the clutch that is to be engaged is continued. With this control,
the engaging force of the clutch that is to be engaged is increased
in accordance with timing when the rotational speed of the input
shaft increases to the rotational speed corresponding to the low
speed step to which a downshift is performed.
[0100] Thereafter, the control step flag FlagRL of the clutch that
is to be disengaged is switched to "4" and when the control step of
the clutch that is to be disengaged advances to the final pressure
decreasing control, the routine proceeds from Step S711 to Step
S712 where the control step flag FlagAP of the clutch that is to be
engaged is set at "4."
[0101] With this, the pressure increasing control of the clutch
that is to be engaged is finished and the routine proceeds to Step
S713 where the final pressure increasing control of increasing the
command value of hydraulic pressure for the clutch that is to be
engaged to the highest hydraulic pressure is performed. It is
determined in Step S714 during performing this final pressure
increasing control whether or not the command value of hydraulic
pressure for the clutch that is to be engaged reaches the highest
hydraulic pressure. Then, when the command value of hydraulic
pressure for the clutch that is to be engaged reaches the highest
hydraulic pressure, the routine proceeds to Step S715 where the
control step flag FlagAP is set at "5" and the control of hydraulic
pressure for the clutch that is to be engaged is completely
finished.
[Routine for Controlling Hydraulic Pressure for Multiple Shift]
[0102] A routine for controlling hydraulic pressure for a multiple
shift, which is shown in FIG. 18, is a sub-routine started in Step
S505 of the routine for controlling hydraulic pressure for a shift,
which is shown in FIG. 15. When this routine is started, first, a
multiple shift pattern is determined in Step S801 to select any one
of operations of hydraulic control at the time of a shift change,
shift cancellation, and continuous shift preparation.
[0103] When a shift change is selected in this Step S801,
processing in Steps 802 to 809 is performed to control hydraulic
pressure applied to the clutches (including brakes, ditto for the
following), which are to be completely engaged or completely
disengaged by the shift change, in the following manner. First, in
Step 802, it is determined whether or not there is a clutch that is
to be engaged at the time of the shift change. When it is
determined that there is a clutch to be completely engaged at the
time of the shift change, the routine proceeds to Step S803 where
the pressure increasing control of increasing the command value of
hydraulic pressure for the clutch to the highest hydraulic pressure
is performed. It is determined in Step 804 during this pressure
increasing control whether or not the command value of hydraulic
pressure for the clutch reaches the highest hydraulic pressure.
When the command value of hydraulic pressure for the clutch reaches
the highest hydraulic pressure, the routine proceeds to Step S805
where the pressure increasing control of the clutch that is to be
engaged at the time of the shift change is finished.
[0104] Then, it is determined in the next Step S806 whether or not
there is a clutch that is to be disengaged at the time of the shift
change. When there is a clutch that is to be completely disengaged
at the time of the shift change, the hydraulic pressure decreasing
control of decreasing the command value of hydraulic pressure for
the clutch that is to be completely disengaged at the time of the
shift change to zero is performed in Step S807. It is determined in
Step S808 during this hydraulic pressure decreasing control whether
or not the hydraulic pressure command value reaches a value not
larger than zero. When the hydraulic pressure command value reaches
the value not larger than zero, the routine proceeds to Step S809
where the pressure increasing control of the clutch that is to be
engaged at the time of the shift change is finished.
[0105] Depending on a shift change pattern, only one of the
engaging control and the disengaging control may be performed. When
both of the engaging control and the disengaging control are
finished, the control at the time of the shift change is
finished.
[0106] When shift cancellation is selected in Step S801, processing
in Steps 810 to 817 is performed to control hydraulic pressure for
the clutches that is to be completely engaged or disengaged by the
shift cancellation in the following manner. First, it is determined
in Step S810 whether or not there is a clutch that is to be engaged
at the time of the shift cancellation. When there is a clutch that
is to be completely engaged at the time of the shift cancellation,
the routine proceeds to Step 811 where the pressure increasing
control of increasing the command value of hydraulic pressure for
the clutch to the highest hydraulic pressure is performed. It is
determined in Step 812 during this pressure increasing control
whether or not the command value of hydraulic pressure for the
clutch reaches the highest hydraulic pressure. When the command
value of hydraulic pressure for the clutch reaches the highest
hydraulic pressure, the routine proceeds to Step S813 where the
pressure increasing control of the clutch that is to be engaged at
the time of the shift cancellation is finished.
[0107] Thereafter, the routine proceeds to Step S814 where it is
determined whether or not there is a, clutch that is to be
disengaged at the time of the shift cancellation. When there is a
clutch that is to be completely disengaged at the time of the shift
cancellation, the routine proceeds to Step S815 where the hydraulic
pressure decreasing control of decreasing the command value of
hydraulic pressure for the clutch that is to be completely
disengaged at the time of the shift change to zero is performed. It
is determined in Step S816 during this hydraulic pressure
decreasing control whether or not the hydraulic pressure command
value reaches a value not larger than zero. When the hydraulic
pressure command value reaches the value not larger than zero, the
routine proceeds to Step S817 where the pressure increasing control
of the clutch that is to be engaged at the time of the shift
cancellation is finished.
[0108] Depending on a shift cancellation pattern, only one of the
engaging control and the disengaging control may be performed. When
both of the engaging control and the disengaging control are
finished, the control at the time of the shift cancellation is
finished.
[0109] When continuous shift preparation is selected in Step S801,
processing in Steps 818 to 825 is performed to control hydraulic
pressure for the clutches, for which engaging preparation or
disengaging preparation is to be made so as to prepare for
continuous shift, in the following manner. First, it is determined
in Step S818 whether or not there is a clutch that is to be engaged
at the time of the continuous shift preparation. When there is a
clutch that is to be engaged at the time of the continuous shift
preparation, the routine proceeds to Step 819 where a routine for
controlling hydraulic pressure for a clutch that is to be engaged
at the time of continuous shift preparation, which will be
described later in FIG. 19, is performed to control hydraulic
pressure for the clutch that is to be engaged for the continuous
shift preparation.
[0110] Thereafter, the routine proceeds to Step S820 where it is
determined whether or not there is a clutch that is to be
disengaged at the time of the continuous shift preparation. When
there is a clutch that is to be disengaged at the time of the
continuous shift preparation, the routine proceeds to Step S821
where the control of holding the hydraulic pressure for the clutch
that is to be disengaged at the time of the continuous shift
preparation is performed. This hydraulic pressure held for
preparing the disengagement of a clutch is set at a value not
smaller than the torque capacity of the clutch for the purpose of
avoiding a delay in response of the hydraulic pressure for
disengaging the clutch when the next shift is started.
[0111] Then, it is determined in the next Step S822 whether or not
the continuous shift preparation is cancelled. When it is
determined that the continuous shift preparation is cancelled, the
routine proceeds to Step S823 where the control of engaging or
disengaging a clutch, for which the continuous shift preparation is
cancelled, is performed.
[0112] Thereafter, the routine proceeds to Step S824 where it is
determined whether or not the next shift is allowed. At this time,
whether or not the next shift is allowed is determined by whether
or not the shift in the process is finished. The control of
hydraulic pressure for the clutches, which has been described in
Steps 819 and 821, is continued until there is brought about a
state where the next shift is allowed. Then, when the next shift is
allowed, the routine proceeds to Step S825 where the control of
hydraulic pressure for a clutch that is to be disengaged performs
the control of hydraulic pressure for a shift to a clutch, which
has the control for continuous shift preparation performed thereto
and thereby has continuous shift preparation performed thereto,
from a state in which the control step flag FlagRL is "1" and where
the control of hydraulic pressure for a clutch that is to be
engaged performs the control of hydraulic pressure for a shift to
the clutch from a state in which the control step flag FlagAP is
"2." Depending on the shift pattern of the continuous shift
preparation, only one of the engaging control and the disengaging
control may be performed.
[0113] By performing the shift control of the respective steps of
the routine for controlling hydraulic pressure for a multiple
shift, which has been described in FIG. 18, the control of
hydraulic pressure for a shift including a multiple shift is
performed as appropriate to operate hydraulic sequences shown in
FIG. 4 to FIG. 7.
[Routine for Controlling Hydraulic Pressure for Clutch that is to
be Engaged at the Time of Continuous Shift Preparation]
[0114] A routine for controlling hydraulic pressure for a clutch
that is to be engaged at the time of continuous shift preparation,
which is described in FIG. 19, is a sub-routine started in Step
S819 of the routine for controlling hydraulic pressure for a
multiple shift in FIG. 18. When this routine is started, first, a
control step flag FlagPreAP is determined in Step S901. When the
control of hydraulic pressure for a clutch that is to be engaged is
started, the control step flag FlagPreAP is set at an initial value
(0) and hence the routine proceeds to Step S902. In this step, the
command value of hydraulic pressure for the clutch that is to be
engaged is set at a specified filling hydraulic pressure in such a
way that the clutch that is to be engaged is brought to a state
just before developing an engaging force and the filling control of
filling the clutch that is to be engaged with the hydraulic oil is
performed. Then, the routine proceeds to the next Step S903 where
the control step flag FlagPreAP is set at "1" and then the present
routine is finished.
[0115] When the present routine is started next time, the control
step flag FlagPreAP is already set at "1" and hence the routine
proceeds to Step S904 where the filling hydraulic pressure is held.
Then, the routine proceeds to Step S905 where it is determined
whether or not a specified time passes. Here, this specified time
is a standard (average) time required for the clutch that is to be
engaged to be brought by the filling control to a state just before
developing an engaging force and is previously set by experiment,
simulation, or the like.
[0116] Thereafter, when a filling control time reaches a specified
time (when the clutch that is to be engaged is brought by the
filling control to a state just before developing an engaging
force), the routine proceeds from Step S905 to Step S906 where the
control step flag FlagPreAP is set at "2" and where the command
value of hydraulic pressure for the clutch that is to be engaged is
decreased to the standby hydraulic pressure and where the filling
control is finished. Thereafter, the clutch that is to be engaged
is held in a state just before developing an engaging force by the
standby hydraulic pressure.
[Routine for Setting Performance of Shift]
[0117] A routine for setting performance of a shift, which is
described in FIG. 23, is a sub-routine started in Step S205 of the
routine for setting a target shift step and a shift performance
state. When the present routine is started, first, in Step S1001,
the kind of a shift to be performed is set from the present shift
step and a target shift step set in Step S204 shown in FIG. 9.
Then, in the next Step S1002, a clutch that is to be disengaged,
which is switched from being engaged to being disengaged, is set
according to the kind of a shift to be performed. Then, the routine
proceeds to Step S1003 where the control flag FlagRL of the clutch
that is to be disengaged is reset.
[0118] Thereafter, the routine proceeds to Step S1004 where the
clutch that is to be engaged, which is switched from being
disengaged to being engaged, is set. Then, the routine proceeds to
Step S1005 where the control flag FlagAP of the clutch that is to
be engaged is reset and the present routine is finished.
[Routine for Setting Performance of Shift Change]
[0119] A routine for setting performance of a shift change, which
is described in FIG. 24, is a sub-routine started in Step S307 of
the routine for determining and setting a multiple shift, which has
been described in FIG. 10. When this routine is started, first, a
multiple shift performance flag is set (ON) in Step S1101 and then
the routine proceeds to Step S1102 where a multiple shift pattern
is set at "shift change." Then, the routine proceeds to Step S1103
where the kind of a shift to be performed is changed from the
present shift step and the target shift step and the clutch that is
to be changed for the shift change is set in the next step
1104.
[0120] Thereafter, the routine proceeds to Step S1105 where it is
determined whether or not there is a shift change in a clutch that
is to be disengaged. When there is a shift change in a clutch that
is to be disengaged, the routine proceeds to Step S1106 where a
change in the clutch that is to be disengaged is set. Then, the
proceeds to Step S1107 where the control step flag FlagRL of a
clutch that is to be disengaged is reset. Then, the routine
proceeds to Step S1108 where a clutch, to which the control of
increasing hydraulic pressure for engaging is performed at the time
of shift change, is set. When there is not a shift change of a
clutch that is to be disengaged, the processings in Steps S1106 to
S1108 are not performed.
[0121] Thereafter, the routine proceeds to Step S1109 where it is
determined whether or not there is a shift change in a clutch that
is to be engaged. When there is a shift change in a clutch that is
to be engaged, the routine proceeds to Step S1110 where a change in
a clutch that is to be engaged is set. Then, the routine proceeds
to Step S1111 where the control step flag FlagAP of a clutch that
is to be engaged is reset. Then, the routine proceeds to Step S1112
where a clutch, to which the control of decreasing hydraulic
pressure for disengaging is performed at the time of shift change,
is set. When there is not a shift change in a clutch that is to be
engaged, the processings in Steps S1109 to S1112 are not
performed.
[0122] Thereafter, the routine proceeds to Step S1113 where a
change in the time during which the control of engaging or
disengaging the clutches that are to be continuously engaged or
disengaged is continued (that is, a specified lapse of time) is
set. Then, the routine proceeds to Step S1114 where a change in the
gradient of the control of increasing hydraulic pressure or the
control of decreasing hydraulic pressure for a clutch that is to be
continuously engaged or disengaged is set and the present routine
is finished.
[Routine for Setting Performance of Shift Cancellation]
[0123] A routine for setting performance of shift cancellation,
which is described in FIG. 25, is a sub-routine started in Step
S310 of the routine for determining and setting a multiple shift,
which has been described in FIG.10. When this routine is started,
first, the multiple shift performance flag is set (ON) in Step
S1201 and then the routine proceeds to Step S1202 where the
multiple shift pattern is set at "shift cancellation." Then, the
routine proceeds to Step S1203 where a clutch to be cancelled is
set.
[0124] Thereafter, the routine proceeds to Step S1204 where it is
determined whether or not there is cancellation of a clutch that is
to be disengaged. When there is cancellation of a clutch that is to
be disengaged, the routine proceeds to Step S1205 where a change in
a clutch that is to be disengaged is set. Then, the proceeds to
Step S1206 where the control step flag FlagRL of the clutch that is
to be disengaged is reset. Then, the routine proceeds to Step S1207
where a clutch, to which the control of increasing hydraulic
pressure for engaging is performed at the time of shift
cancellation, is set. When there is not cancellation of a clutch
that is to be disengaged, the processing in these Steps S1205 to
S1207 is not performed.
[0125] Thereafter, the routine proceeds to Step S1208 where it is
determined whether or not there is cancellation of a clutch that is
to be engaged. When there is cancellation of a clutch that is to be
engaged, the routine proceeds to Step S1209 where a change in the
clutch that is to be engaged is set. Then, the routine proceeds to
Step S1210 where the control step flag FlagAP of the clutch that is
to be engaged is reset. Then, the routine proceeds to Step S1211
where a clutch, to which the control of decreasing hydraulic
pressure for disengaging is performed at the time of shift
cancellation, is set. When there is not cancellation of a clutch
that is to be engaged, the processings in Steps S1 208 to S1 211
are not performed.
[Routine for Setting Continuous Performance of Shift
Preparation]
[0126] A routine for setting continuous performance of shift
preparation, which is described in FIG. 26, is a sub-routine
started in Step S312 of the routine for determining and setting a
multiple shift, which has been described in FIG. 10. When this
routine is started, first, it is determined in Step S1301 whether
or not continuous shift preparation is being performed. Then, when
continuous shift preparation is not being performed, the routine
proceeds to Step S1302 where the multiple shift performance flag is
set (ON) and the multiple shift pattern is set at "continuous shift
preparation." Then, the routine proceeds to Step S1304 where the
kind of a shift, in which continuous shift preparation is
performed, is set. Then, the routine proceeds to the next Step S1
305 where a clutch for which continuous shift is prepared is
set.
[0127] Thereafter, the routine proceeds to Step S1306 where it is
determined whether or not there is continuous shift preparation of
a clutch that is to be disengaged. When there is the continuous
shift preparation of a clutch that is to be disengaged, the routine
proceeds to Step S1307 where a clutch, to which the control of
holding hydraulic pressure for disengaging at the time of
continuous shift preparation is performed, is set. When there is
not continuous shift preparation of a clutch that is to be
disengaged, the processing in this Step S1307 is not performed.
[0128] Thereafter, the routine proceeds to Step S1308 where it is
determined whether or not there is continuous shift preparation of
a clutch that is to be engaged. When there is continuous shift
preparation of a clutch that is to be engaged, the routine proceeds
to Step S1309 where a clutch, to which the control of holding
hydraulic pressure for engaging is performed at the time of
continuous shift preparation, is set. Then, the routine proceeds to
Step S1310 where the control step flag FlagPreAP of a clutch that
is to be engaged is reset and the present routine is finished. When
there is not continuous shift preparation of a clutch that is to be
engaged, the processings in Steps S1309 to S1310 are not
performed.
[0129] Meanwhile, when it is determined in Step S1301 that
continuous shift preparation is in process, the routine proceeds to
Step S1311 where it is determined whether or not there is a change
in the multiple target shift step. When it is determined that there
is not a change in the multiple target shift step, the present
routine is finished without performing the subsequent
processing.
[0130] When it is determined in Step S1311 that there is a change
in the multiple target shift step, the routine proceeds to Step
S1312 where the kind of a shift, in which continuous shift
preparation is performed, is changed and in the next Step S1313, a
clutch for which continuous shift preparation is performed is
changed. Then, the routine proceeds to Step S1314 where it is
determined whether or not there is a change in the clutch that is
to be disengaged at the time of the continuous shift preparation.
When it is determined that there is a change in the clutch that is
to be disengaged at the time of the continuous shift preparation,
the routine proceeds to Step S1315 where cancellation of a clutch,
which is in process of being subjected to the control of holding
hydraulic pressure for disengaging at the time of the continuous
shift preparation, is set. Then, the routine proceeds to Step S1316
where a change in the clutch, which is subjected to the control of
holding hydraulic pressure for disengaging at the time of the
continuous shift preparation, is set. When it is determined that
there is not a change in the clutch that is to be disengaged at the
time of the continuous shift preparation, the processing in these
Steps S1315 and S1316 is not performed.
[0131] Thereafter, the routine proceeds to Step S1317 where it is
determined whether or not there is a change in the clutch that is
to be engaged at the time of the continuous shift preparation. When
it is determined that there is a change in the clutch that is to be
engaged at the time of the continuous shift preparation, the
routine proceeds to Step S1318 where cancellation of a clutch,
which is in process of being subjected to the control of holding
hydraulic pressure for engaging at the time of the continuous shift
preparation, is set. Then, the routine proceeds to Step S1319 where
a change in the clutch, which is subjected to the control of
holding hydraulic pressure for engaging at the time of the
continuous shift preparation, is set and in the next Step S1320,
the control step flag FlagPreAP is reset and the present routine is
finished. When it is determined that there is not a change in the
clutch that is to be engaged at the time of the continuous shift
preparation, the processing in these Steps S1318 to S1320 is not
performed.
[0132] In the multiple shift control of the present embodiment
described above, when a request to switch to a shift to a new third
shift step is made during performing a shift from a first shift
step to a second shift step, a method for performing a shift to the
third shift step is changed according to a combination pattern of
engagement and disengagement (engagement pattern) of the respective
friction engaging components (the respective clutches C0, C1, and
C2, and the respective brakes B0, B1, B2, and B3) in the steady
state of the third shift step. Hence, when the request to switch to
the shift to the new third shift step is made during performing the
shift from the first shift step to the second shift step, it is
possible to select an appropriate shift method in consideration of
the relationship between the engagement pattern of the respective
friction engaging components at that time and the engagement
pattern of the new third shift step and to perform a multiple
shift. Therefore, it is possible to prevent a shift shock caused by
the multiple shift and at the same time to perform the multiple
shift with excellent responsivity.
[0133] Needless to say, the present invention can be applied to not
only a five-speed automatic transmission but also a four-speed or
less or six-speed or more automatic transmission.
* * * * *