JP3302776B2 - Control device for automatic transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a control device for controlling a torque reduction at the time of shifting of an automatic transmission mounted on a vehicle.

[0002]

2. Description of the Related Art Conventionally, as described in Japanese Patent Publication No. 4-31891, for example, in an automatic transmission having a multi-stage transmission mechanism using a planetary gear mechanism or the like, a predetermined amount of engine torque is changed during shifting. There has been proposed a control device for an automatic transmission that reduces a shift shock by only reducing the speed.

The control device of such an automatic transmission reads the start timing, the end timing and the amount of torque reduction of the torque reduction from a map using the throttle opening TVO as a parameter.
The torque down control is performed based on the end timing and the torque down amount.

[0004] As described in Japanese Patent Application Laid-Open No. 2-233867, in order to improve the fuel efficiency of the engine, the air-fuel ratio of the air-fuel mixture supplied to the engine at a low load with a small throttle opening TVO is used. To the throttle opening TV
There has been proposed an apparatus in which the air-fuel ratio is set in accordance with the operation state so that the air-fuel ratio is leaner than the air-fuel ratio at a high load when O is large.

[0005]

However, in the case of setting the air-fuel ratio in accordance with such an operation state, a change in the throttle opening TVO and a change in the air-fuel ratio are temporally reduced due to a response delay of the control means. A situation arises in which they do not match.
For this reason, the engine torque does not coincide with the change in the throttle opening TVO, and this affects the torque down control at the time of shifting.

For example, at the time of a downshift accompanying the depression of the accelerator pedal (at the time of shifting from a high speed stage to a low speed stage), an increase in engine torque is delayed due to a delay in response of the air-fuel ratio to a change in the throttle opening TVO. In this case, if the delay in the increase in the engine torque is not taken into consideration, the situation in which the start of the torque reduction is too early for the increase in the engine torque may occur. For this reason, the increase in the engine torque is suppressed more than necessary, and it takes a long time for the turbine speed of the torque converter of the automatic transmission to reach the speed required for the end of the shift, and the shift time becomes longer. is there.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a control device for an automatic transmission that reduces a shift shock and reduces a shift time in the automatic transmission. I have.

[0008]

The invention according to claim 1 is
In an automatic transmission that changes the power transmission path of a multi-stage transmission mechanism to switch gear stages and that temporarily reduces engine torque during gear shifting,
Operating state detecting means for detecting an operating state of the engine, air-fuel ratio setting means for setting an air-fuel ratio of an air-fuel mixture supplied to the engine in accordance with an output of the operating state detecting means, and torque reduction in accordance with the air-fuel ratio Storage means for storing a value relating to the start timing of, and setting means for setting a required value of the start timing of the torque down according to the air-fuel ratio based on the storage content of the storage means, and a torque-reduction control means for performing torque reduction at the start timing corresponding to the required value during shifting, the setting means is low from the high speed stage
When the air-fuel ratio at the time of shifting to the
The start timing of the torque reduction when the air-fuel ratio is rich.
Is configured to be later than the start timing of the
Is what it is.

According to a second aspect of the present invention, there is provided a dynamic transmission of a multi-stage transmission mechanism.
Changing the gear stage by changing the force transmission path,
Torque that temporarily reduces engine torque at high speed
In an automatic transmission that goes down, the engine
Operating state detecting means for detecting the operating state;
Air-fuel ratio of air-fuel mixture supplied to engine according to stage output
Air-fuel ratio setting means for setting the
Value related to the amount of torque down and the timing of the start of torque reduction
Storage means for storing values relating to
Based on the memory content, the amount of torque reduction
Set the required value and the required value for the torque-down start timing.
Setting means for setting the torque and the torque corresponding to the required value at the time of shifting.
Torque reduction with the down amount and start timing
Control means, and the setting means includes:
When the air-fuel ratio at the time of shifting from
The air-fuel ratio when the air-fuel ratio is rich, and
First, delay the start timing of torque reduction.
It has been done.

[0010]

[0011]

[0012]

According to the first aspect of the present invention, the operating condition of the engine is detected, and the air-fuel ratio is set according to the operating condition. In addition, the torque of the engine is temporarily reduced during the shift of the multi-speed transmission mechanism. Then, by setting the required value of the start timing of the torque down according to the air-fuel ratio, the torque-down control adapted to the engine torque that changes according to the change in the air-fuel ratio is performed, thereby reducing the shift shock. And the shift time is shortened.

That is, when the air-fuel ratio during the shift from the high gear to the low gear is lean, the start timing of the torque-down when the air-fuel ratio is lean is later than the start timing of the torque-down when the air-fuel ratio is rich. The time during which the engine torque, which has been reduced due to the leanness, is further reduced by the torque reduction is shortened, and the shift time is shortened.

[0014]

According to the second aspect of the present invention, when the air-fuel ratio during the shift from the high gear to the low gear is rich, the torque down amount and the start timing of the torque down are as follows.
When the air-fuel ratio is lean, the amount of torque reduction becomes smaller,
In addition, since the start timing when the air-fuel ratio is lean is delayed, it is possible to prevent the engine torque from being further reduced due to the torque reduction, and to shorten the time during which the engine torque decreases due to the torque reduction.

[0016]

FIG. 1 shows an embodiment of a control device for an automatic transmission according to the present invention. The automatic transmission AT includes a torque converter 2, a multi-stage transmission mechanism 10 connected to an output side thereof, and a hydraulic control circuit 30. The multi-stage transmission mechanism 10 incorporates various friction elements (clutches, brakes) that change the power transmission path to change the gear position. The engagement and release of these various friction elements are controlled by the hydraulic control circuit 30. It has become so.

That is, the hydraulic control circuit 30 has hydraulic pressure supply / discharge control elements composed of various shift valves for switching between supply and discharge of hydraulic pressure (line pressure) to each friction element. By controlling in accordance with the control signal output from the unit 60, supply / discharge control of the operating pressure to the friction element of the multi-stage transmission mechanism 10 is executed.

The control unit 60 stores a microcomputer as a control device and various maps storing torque down amount, torque down start timing, torque down correction coefficient, torque down start timing correction coefficient, and the like, which will be described later. Memory (not shown). The control unit 60
The output signal of the throttle opening sensor 61 for detecting the opening of the throttle valve disposed in the intake pipe, the turbine speed for detecting the turbine speed of the torque converter 2 corresponding to the speed on the input side of the transmission. The output signal of the sensor 62 is input.

The control unit 60 further includes an output signal from a linear O2 sensor 63 disposed in the exhaust pipe for detecting the oxygen concentration in the exhaust gas, and an output signal from an air flow meter 64 for detecting the amount of intake air to the engine. Also, an output signal of a vehicle speed sensor 65 for detecting the vehicle speed from the rotation of the axle (output shaft) is input.

The control unit 60 sets a shift speed by comparing a shift pattern in which a shift line is determined in advance with an operation state detected based on a throttle opening, a vehicle speed, a turbine speed, or the like. There is provided a shift speed setting means 601 for outputting a shift signal corresponding to the shift speed to a shift valve or the like of the hydraulic control circuit 30 to perform a shift.

The control unit 60 is supplied with operating state detecting means 602 for detecting the operating state of the engine according to the output signal of the throttle opening sensor 61, and is supplied to the engine according to the output signal of the linear O2 sensor 63. Air-fuel ratio detecting means 603 for detecting the air-fuel ratio of the air-fuel mixture,
An air-fuel ratio setting means 604 for setting a target air-fuel ratio in response to an output signal of the operating state detecting means 602, and an air-fuel ratio setting means 604 and an air-fuel ratio detecting means 603 are provided in the intake pipe in response to the output signals. A fuel injection amount control means 605 for controlling the fuel injection amount of the fuel injection means 60a; and a shift detection means 6 for detecting the start of a shift by the shift speed setting means 601
06, setting means 607 for setting the torque down amount and the torque start timing according to the air-fuel ratio, and controlling the ignition timing of, for example, the ignition device 60b of the engine when the shift start is detected by the shift detection means 606. And a torque reduction control means 608 for temporarily reducing the torque of the engine.

When the control unit 60 detects that the engine is in a low-load operation state with a small throttle opening, the control unit 60 shifts the air-fuel ratio to a lean side leaner than the stoichiometric air-fuel ratio, while increasing the throttle opening. When it is detected that the driving state is large and high load, the air-fuel ratio is set to the rich side.

FIG. 2 shows a torque converter 2 of the automatic transmission.
1 shows an example of the structure of a multi-speed transmission mechanism 10. The torque converter 2 includes a pump 3 fixed in a case connected to the output shaft 1 of the engine, and a turbine 4 arranged to face the pump 3 and driven by the pump 3 via hydraulic oil. And a stator 5 interposed between the pump 3 and the turbine 4 and supported on a fixed shaft 7 via a one-way clutch 6.

The multi-speed transmission mechanism 10 has a central shaft 12 for driving an oil pump having a base end fixed to the output shaft 1 of the engine and a front end connected to an oil pump 31. On the other hand, a hollow turbine shaft 13 having a base end connected to the turbine 4 of the torque converter 2 is provided, and a Ravigneaux type planetary gear device 14 is provided on the turbine shaft 13. The planetary gear device 14 includes a small-diameter sun gear 15, a large-diameter sun gear 16, a long pinion gear 17, a short pinion gear 18, and a ring gear 19. The following various friction elements are incorporated in the planetary gear device 14.

A forward clutch 20 and a coast clutch 21 are arranged in parallel between the turbine shaft 13 and the small-diameter sun gear 15 on the side remote from the engine. The forward clutch 20 has a first
Power transmission from the turbine shaft 13 to the small-diameter sun gear 15 via the one-way clutch 22 of FIG.
The coast clutch 21 intermittently transmits and receives power between the turbine shaft 13 and the small-diameter sun gear 15.

A 2-4 brake 23 having a brake drum 23a connected to the large-diameter sun gear 16 and a brake band 23b applied to the brake drum 23a is disposed radially outward of the coast clutch 21. When the 2-4 brake 23 is engaged, the large-diameter sun gear 16 is fixed. This 2
-4 beside the brake drum 23
a reverse clutch 24 for reverse running which interrupts power transmission between the large-diameter sun gear 16 and the turbine shaft 13 via a.
Is arranged. A low reverse brake 25 for engaging and disengaging the carrier 14a and the case 10a is provided between the carrier 14a of the planetary gear device 14 and the case 10a of the multi-stage transmission mechanism 10 radially outward of the planetary gear device 14. Is arranged, and in parallel with this, the second
The one-way clutch 26 is disposed.

Further, a 3-4 clutch 27 for intermittently transmitting power between the carrier 14a and the turbine shaft 13 is disposed on the side of the planetary gear unit 14 on the engine side. On the side of the 3-4 clutch 27, an output gear 28 connected to the ring gear 19 is arranged, and this gear 28 is connected to an output shaft 28a.
Mounted on 29 is the output shaft 1 of the engine.
And a lock-up clutch for directly connecting the turbine shaft 13 and the turbine shaft 13 without passing through the torque converter 2.

The multi-speed transmission mechanism 10 itself has four forward speeds and one reverse speed, and has clutches 20, 21,
The required gear stage can be obtained by appropriately operating the friction elements consisting of the brakes 24, 27 and the brakes 23, 25. Table 1 below shows the operating relationship between each gear and the clutch and brake.

[0029]

[Table 1]

FIG. 3 shows a hydraulic control circuit 30 in the automatic transmission. The hydraulic control circuit 30 has an oil pump 31 driven by the output shaft 1, and hydraulic oil is discharged from the pump 31 to an oil passage L1. The hydraulic oil discharged from the pump 31 to the oil passage L1 is guided to the pressure regulator valve 32. The pressure regulator valve 32 regulates the hydraulic pressure (line pressure) of the hydraulic oil from the pump 31, and is controlled by a duty solenoid valve 33.

That is, the duty of the hydraulic oil pressure of the hydraulic oil reduced to a predetermined pressure by the solenoid reducing valve 34 is controlled by the duty solenoid valve 33, that is, the opening and closing time of the duty solenoid valve 33 is adjusted to control the drain amount. As a result, the hydraulic pressure is controlled, and is supplied to the pressure regulator valve 32 as a pilot pressure, whereby the line pressure is adjusted according to the pilot pressure. Thus, the line pressure variable means is constituted, and the line pressure is controlled by controlling the duty solenoid valve 33 by the control unit 60 as shown in FIG.

The line pressure regulated by the pressure regulator valve 32 is applied to a manual shift valve 35.
Is supplied to the port g. The manual shift valve 35 is manually shifted to the P, N, D, 2.1 ranges, and the hydraulic oil is supplied from the port g to a predetermined port in each range. The port g communicates with the ports a and e when the manual shift valve 35 is set to one range, communicates with the ports a and c when the manual shift valve 35 is set to two ranges, and when the manual shift valve 35 is set to the D range. It is connected to ports a and c, and is connected to port f when it is set to the R range.

Port a of manual shift valve 35
Is connected to the 1-2 shift valve 36 via the oil passage L2. A pilot pressure controlled by a 1-2 solenoid valve 37 acts on the 1-2 shift valve 36. In the first gear, 1-2
When the solenoid valve 37 is turned off, 1
The spool of the -2 shift valve 36 is actuated to the left side in the figure, and the oil passage L3 communicating with the apply chamber 23c of the 2-4 brake 23 is communicated with the drain side.
When the solenoid valve 37 is turned on, 1-
The spool of the two-shift valve 36 is actuated to the right in the drawing, and the hydraulic pressure from the port a is supplied to the apply chamber 23c of the 2-4 brake 23. Further, the 1-2 shift valve 36 supplies the hydraulic oil supplied from the port e of the manual shift valve 35 via the low pressure reducing valve 38 to the low reverse brake 25 at the first speed stage of one range. It has become.

The hydraulic pressure from the port a of the manual shift valve 35 is also supplied to the 2-3 shift valve 39 as pilot pressure. This 2-3 shift valve 39 is
The pilot pressure is controlled by a 2-3 solenoid valve 40 while being connected to a port c of the manual valve 35 via an oil passage L4. And the first and second
At high speed, the 2-3 solenoid valve 40 is turned on, so that the spool of the 2-3 shift valve 39 is actuated to the right in the drawing. In this state, the oil passage L5 communicating with the 3-4 clutch 27 communicates with the drain side. 3-4 clutch 27
Is released. In the third and fourth speeds, the 2-3 solenoid valve 40 is turned off, so that the spool of the 2-3 shift valve 39 is actuated to the left in the drawing. Sent to L5 3
-4 clutch 27 is engaged.

The oil passage L5 is also connected to a 3-4 shift valve 41.
The pilot pressure controlled by the 3-4 solenoid valve 42 is acting. Then, at the 1st, 2nd and 4th gears of the D range and at the 1st gear of the 2 range, 3-4
When the solenoid valve 42 is turned on, 3-
The spool of the 4-shift valve 41 is actuated to the right in the figure,
In this state, the oil passage L6 communicating with the release chamber 23d of the 2-4 brake 23 is communicated with the drain side.

At the third speed stage of the D range, at the second and third speed stages of the two range, and at the first and second speed stages of the one range, 3-4
When the solenoid valve 42 is turned off, 2
The spool of the third shift valve 39 is operated on the left side of the drawing, and in this state, the oil passage L6 and the 2-3 shift valve 3 are moved.
9 is connected to the oil passage L5, and the supply and discharge of the hydraulic pressure to and from the release chamber 23d is performed according to the operation of the 2-3 shift valve 39. Further, the 3-4 shift valve 41 has an oil passage L7 communicating with the port a of the manual shift valve 35 and an oil passage L8 communicating with the coast clutch 21.
The coast clutch 21 is released and engaged in response to the switching between supply and discharge of the hydraulic pressure.

Thus, the solenoid valves 37, 40,
Each shift valve 36, 3 controlled by 42
According to the operations of the gears 9 and 41, the frictional element for shifting 2-4
The brake 23 (which is engaged when the hydraulic pressure is supplied to the apply chamber 23c and the hydraulic pressure in the release chamber 23d is drained and released otherwise) and the engagement and release of the 3-4 clutch 27 are as shown in Table 1 above. It is performed. Further, each shift valve 36, 39, 41 and 2-4 brakes 23 and 3
In a hydraulic circuit between the clutch 4 and the clutch 27, a 1-2 accumulator 43, a 2-3 accumulator 44, a 2-3 timing valve 45, a 3-2
A timing valve 46 and a bypass valve 47 are incorporated.

The hydraulic control circuit 30 also includes:
An oil passage L9 for sending hydraulic pressure from the port a so as to engage the forward clutch in the D, 2, 1 range, an ND accumulator 48 connected thereto, and a port f to engage the reverse clutch 24 in the R range. And an N-R accumulator 49 connected thereto, a lock-up control valve 50 for controlling the lock-up clutch 29, a lock-up solenoid valve 51 for controlling the same, a converter relief valve 52, and the like. ing.

FIG. 4 is a flowchart showing a specific example of the torque down control operation by the control unit 60. In this flowchart, when the engine is started, first, each detected value is initialized, and various output signals of the vehicle speed sensor 65, the linear O2 sensor 63, the throttle opening sensor 61, and the like are read (steps S1 and S2).

Then, in step S3, it is determined whether or not the current time is the time of starting the shift (upshift) from the low gear to the high gear, and if the current time is other than the start of the upshift (NO in step S3). In step S4, it is determined whether or not the current time point is a time point at which a shift from a high gear to a low gear (downshift) starts. If the current time is not the start time of the downshift (step S4
NO), the output signal of the throttle opening sensor 61 and the like is read again in order to return to step S2 and determine the shift state and the like.

On the other hand, if the current time is the start of the upshift (YES in step S3), after the target torque reduction amount TD is obtained by the processing in steps S5 to S7 described later, the ignition of the ignition device 60b is performed. By controlling the timing, control is performed so that the torque reduction amount becomes the target torque reduction amount TD (step S8). Thereafter, the process returns to step S2.

On the other hand, if the current time is the start time of the downshift (YES in step S4), a required value for torque down is calculated by a subroutine described later (step S9), and the required value is set to this required value. The ignition timing of the ignition device 60b is controlled (step S8). Thereafter, the process returns to step S2.

Next, a first embodiment of the torque down control at the time of the downshift in step S9 will be described with reference to a subroutine of FIG. In the subroutine of FIG. 5, the start timing of the torque reduction is set according to the air-fuel ratio.

That is, the torque down amount TDU corresponding to the throttle opening TVO is read from the map of FIG. 6 (step S11). The torque reduction amount TDU in FIG.
Is set to be larger as the throttle opening TVO is larger.

Next, the torque-down start timing GSTD corresponding to the throttle opening TVO and the vehicle speed VSP is read from the map of FIG. 7 (step S12).

The torque-down start timing GST shown in FIG.
D is set to increase as the throttle opening TVO increases, and to decrease as the vehicle speed VSP increases. In addition,
The torque down end timing GEND is set to a fixed timing.

Next, in order to obtain the torque-down start timing correction coefficient KGSTD using the air-fuel ratio obtained based on the output signal of the linear O2 sensor 63, the torque-down start timing correction coefficient corresponding to the air-fuel ratio is obtained from the map shown in FIG. KGSTD is read (step S1
3). That is, the torque down start timing G in FIG.
Since the STD is set according to the throttle opening TVO and does not consider the air-fuel ratio, the torque-down start according to the air-fuel ratio is determined from the map of FIG. 8 in order to set the torque-down start timing according to the air-fuel ratio. Timing correction coefficient K
Read GSTD.

The torque-down start timing correction coefficient KGSTD shown in FIG.
0, and as the air-fuel ratio becomes leaner than the stoichiometric air-fuel ratio,
It is set to be a large value. Further, the torque down start timing correction coefficient KGSTD is set so as to become smaller as the air-fuel ratio becomes richer than the stoichiometric air-fuel ratio, and to gradually become larger after the air-fuel ratio becomes minimum at a predetermined air-fuel ratio.

The torque down start timing GSTD and the torque down start timing correction coefficient KGS
Target torque reduction start timing STD according to TD
(= KGSTD × GSTD) is calculated (Step S)
14). Thereafter, the process proceeds to step S8, and the ignition device 6 is controlled so that the target torque reduction start timing STD is reached.
The ignition timing of 0b is controlled.

Next, the operation at the time of downshift by the processing of the flowchart of FIG. 5 will be described with reference to FIG. At the start of the downshift (time t1), the air-fuel ratio is set leaner than the stoichiometric air-fuel ratio.

At time t1, the air-fuel ratio is lean.
Is set to a value larger than 1.0, and the target torque-down start timing STD (time t3 in the figure) is set to be later than when the air-fuel ratio is rich. Is done.

Thus, even if the engine torque rises later than the throttle opening TVO due to the response delay of the air-fuel ratio at the time of the downshift, the torque can be reduced in accordance with the engine torque.

For example, as in the conventional case, the throttle opening TV
When the torque-down start timing is set in accordance with only O, as shown by the two-dot chain line in FIG. 9, the torque-down is started at time t2 earlier than the time t3 described above, and the engine torque does not increase much. The torque will be reduced in the meantime. For this reason, the rise of the turbine speed TREV is delayed, so that the end of the shift is delayed, and the responsiveness of the shift control is deteriorated.

On the other hand, the target torque-down start timing STD is set by the torque-down start timing correction coefficient KGSTD so that the start of the torque-down is delayed.
The decrease in the rate of increase in EV is reduced, the shift time can be shortened, and the responsiveness of shift control is improved.

Next, a second embodiment of the subroutine of the torque down control at the time of the downshift in step S9 will be described with reference to FIG. In the subroutine of FIG. 10, the amount of torque reduction is set according to the air-fuel ratio.

That is, the torque down amount TDU corresponding to the throttle opening TVO is read from the map of FIG. 6, and the torque down correction coefficient KTDU corresponding to the air-fuel ratio is read from the map of FIG. 11 (steps S21 and S21).
22).

The torque down correction coefficient KTDU shown in FIG.
Is set to 1.0 when the air-fuel ratio is the stoichiometric air-fuel ratio, and to be smaller as the air-fuel ratio becomes leaner than the stoichiometric air-fuel ratio. Further, the torque-down correction coefficient KTDU is set so as to increase as the air-fuel ratio becomes richer than the stoichiometric air-fuel ratio, and to gradually decrease after peaking at a predetermined air-fuel ratio.

Next, the throttle opening TVO is obtained from the map.
Then, the torque down start timing GSTD and the torque down end timing GEND corresponding to the vehicle speed VSP are read (step S23). Then, a target torque down amount TD (= TDU × KTDU) is calculated from the torque down amount TDU and the torque down correction coefficient KTDU (step S24). Thereafter, step S8
The ignition timing of the ignition device 60b is controlled so that the target torque reduction amount TD is reached.

Next, the operation at the time of downshift by the processing of the subroutine of FIG. 10 will be described with reference to FIG.

That is, since the air-fuel ratio is lean at the time t1 at the start of the downshift as described above, the torque down correction coefficient KTDU read from the map of FIG.
Is smaller than 1.0, and the target torque reduction amount T
D is set to a smaller value than when the air-fuel ratio is rich. Therefore, as compared with the case where the torque down amount TDU is set only according to the conventional throttle opening TVO as shown by the two-dot chain line in FIG. 12, the turbine speed TREV is smaller by the smaller target torque down amount TD. And the shift time is shortened, and the responsiveness of the shift control is improved. Also, the turbine speed TREV due to the torque reduction
, The smooth shift can be performed.

Next, a third embodiment of the subroutine of the torque down control at the time of the downshift in step S9 will be described with reference to FIG. In the subroutine of FIG. 13, the start timing and the torque reduction amount are set according to the air-fuel ratio.

That is, from the map, the throttle opening TV
The torque down amount TDU corresponding to O is read, the torque down correction coefficient KTDU corresponding to the air-fuel ratio is read, and the target torque down amount TD (= TDU × KTDU)
Is calculated (steps S31, S32, S36).

Further, from the map, the torque down start timing G corresponding to the throttle opening TVO and the vehicle speed VSP is obtained.
The STD and the torque down end timing GEND are read, the torque down start timing correction coefficient KGSTD corresponding to the air-fuel ratio is read, and the target torque down start timing STD (= KGSTD × GSTD) is calculated (step S33, S34, S35). After this,
In step S8, the ignition timing of the ignition device 60b is controlled so that the target torque reduction amount TD and the target torque reduction start timing STD are reached.

As described above, since the start timing of the torque down at the time of the downshift is delayed according to the air-fuel ratio and the amount of the torque down is reduced, the turbine rotational speed TREV can be rapidly increased, and the speed change control can be performed. Responsiveness is further improved.

Subsequently, the above steps S5 to S7
The operation at the time of the upshift will be described.

That is, the torque down amount TDU corresponding to the throttle opening TVO is read from the map of FIG. 6 (step S5), and the torque down correction coefficient KTDU corresponding to the air-fuel ratio is read from the map of FIG. 11 (step S5). S6). Then, the target torque reduction amount TD (= KTDU) as a required value for torque reduction is determined by the torque reduction amount TDU and the torque reduction correction coefficient KTDU.
× TDU) is calculated (step S7).

Next, the operation at the time of upshift by the processing of steps S5 to S7 will be described with reference to FIG. In the upshift start point (t 1 point), the air-fuel ratio is set richer than the stoichiometric air-fuel ratio.

That is, at time t4 when the upshift starts, the air-fuel ratio is rich, so the torque-down correction coefficient KTDU read from the map of FIG. 11 becomes a value larger than 1.0, and the target torque-down amount TD becomes The air-fuel ratio is set to a larger value than when the air-fuel ratio is lean. Therefore, the conventional throttle opening TV as shown by the two-dot chain line in FIG.
As compared with the case where the torque down amount TDU is set only in accordance with O, the engine torque is suppressed by the larger target torque down amount TD.

Therefore, an increase in the shaft torque during shifting (two-dot chain line in FIG. 14) caused by a delay in lowering the engine torque in response to the response delay of the air-fuel ratio is sufficiently suppressed, and the response delay of the air-fuel ratio is reduced. , The torque can be reduced in accordance with the engine torque that changes in accordance with the engine speed, and the shift shock of the shaft torque during the upshift can be appropriately mitigated.

Next, the operation of controlling the hydraulic pressure (line pressure) of the hydraulic oil supplied to the friction element during the gear shift in order to reduce the gear step and reduce the gear shift time will be described with reference to the flowchart of FIG. Will be explained.

When the shift is started, the line pressure PL corresponding to the throttle opening TVO is read from the map of FIG. 16 (step S41). The line pressure PL in FIG.
The larger the throttle opening TVO, the larger the value.

Next, a line pressure correction coefficient KPL corresponding to the air-fuel ratio is obtained from the map of FIG. 17 (step S).
42). The line pressure correction coefficient KPL in FIG. 17 is set to 1.0 when the air-fuel ratio is the stoichiometric air-fuel ratio, and to be smaller as the air-fuel ratio becomes leaner than the stoichiometric air-fuel ratio. Further, the line pressure correction coefficient KPL is set so as to increase as the air-fuel ratio becomes richer than the stoichiometric air-fuel ratio, and to gradually decrease after peaking at a predetermined air-fuel ratio.

Next, the target line pressure P (= KPL × PL) is calculated based on the line pressure PL and the line pressure correction coefficient KPL.
Is calculated (step S43). Then, the line pressure of the working oil supplied to the friction element is controlled according to the target line pressure P.

For example, as shown in FIG. 18, the engine torque decreases with a decrease in the throttle opening TVO due to the response delay of the air-fuel ratio. However, since the air-fuel ratio at the start of the shift is rich, the engine torque shown in FIG. Is set to a value larger than 1.0, and the target line pressure P is set to a value larger than the line pressure PL (two-dot chain line in FIG. 18). As a result, the change in the shaft torque is reduced and a smooth gear shift is performed as compared with the case where the line pressure PL is set only in accordance with the throttle opening TVO (two-dot chain line in FIG. 18).

This line pressure control is performed not only during gear shifting but also during steady running.

In the above description, the linear O 2 sensor 6
The torque-down control was performed using the air-fuel ratio obtained from the output signal of No. 3, but instead of this air-fuel ratio, the amount of air taken in per unit time obtained based on a detection signal from the air flow meter 64 is indicated. The charging efficiency CE and the pulse width T of the fuel injection injected by the fuel injection means 60a
Control of torque reduction may be performed using the ratio (CE / Ti) with i. In this case, since the linear O2 sensor 63 is not required, the number of sensors can be reduced.

[0077]

As described above, according to the present invention, the air-fuel ratio is set in accordance with the operating state of the engine, and the timing of starting the torque reduction set in accordance with the air-fuel ratio during gear shifting is set.
Since the torque-down control according to the required value of the gearing is performed, the torque-down control suitable for the engine torque can be performed, and the shift time can be shortened while reducing the shift shock.

That is, when the air-fuel ratio at the time of shifting from the high gear to the low gear is lean, the start timing of the torque down is delayed from the start timing of the torque down when the air-fuel ratio is rich. The decrease in the rate of increase in the rotational speed is reduced, the shift time can be shortened, and the responsiveness of the shift control can be improved.

[0079]

Further, when the air-fuel ratio at the time of shifting from the high gear to the low gear is lean, the torque down amount is made smaller than when the air-fuel ratio is rich, and the start timing of the torque down is delayed. The turbine speed can be increased quickly, and the responsiveness of the shift control is further improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a control device for an automatic transmission according to the present invention.

FIG. 2 is an explanatory diagram illustrating a schematic configuration of an automatic transmission.

FIG. 3 is a schematic explanatory diagram of a hydraulic control circuit.

FIG. 4 is a flowchart showing an operation of torque down control during a gear shift.

FIG. 5 is a flowchart showing a first embodiment of a torque down control subroutine performed at the time of a downshift.

FIG. 6 is a map of a torque reduction amount set according to a throttle opening.

FIG. 7 is a map of a torque down start timing set according to a vehicle speed and a throttle opening.

FIG. 8 is a map of a torque-down start timing correction coefficient set according to an air-fuel ratio.

FIG. 9 is a time chart showing an operation of the first embodiment of the torque down control at the time of the downshift.

FIG. 10 is a flowchart showing a second embodiment of a subroutine for torque down control performed at the time of a downshift.

FIG. 11 is a map of a torque down correction coefficient set according to an air-fuel ratio.

FIG. 12 is a time chart illustrating an operation according to a second embodiment of the torque down control at the time of a downshift.

FIG. 13 is a flowchart showing a third embodiment of a subroutine for torque down control performed at the time of a downshift.

FIG. 14 is a time chart showing an operation at the time of an upshift.

FIG. 15 is a flowchart showing an operation of line pressure control.

FIG. 16 is a map of a line pressure set according to a throttle opening.

FIG. 17 is a map of a line pressure correction coefficient set according to an air-fuel ratio.

FIG. 18 is a time chart showing an operation of line pressure control.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine output shaft 2 Torque converter 10 Multi-speed transmission mechanism 60 Control unit 61 Throttle opening sensor 62 Turbine speed sensor 63 Linear O2 sensor 64 Air flow meter 65 Vehicle speed sensor 601 Shift speed setting means 602 Operating state detecting means 603 Air-fuel ratio detecting means 604 air-fuel ratio changing means 605 fuel injection amount control means 606 shift detection means 607 setting means 608 torque down control means

Claims (2)

(57) [Claims] 1. An operation for detecting an operating state of an engine in an automatic transmission that changes a power transmission path of a multi-stage transmission mechanism to switch gear stages and that temporarily reduces the torque of the engine during gear shifting. State detecting means, air-fuel ratio setting means for setting the air-fuel ratio of the air-fuel mixture supplied to the engine in accordance with the output of the operating state detecting means, and a torque-down start time in accordance with the air-fuel ratio
Means for storing a value related to the air-fuel ratio based on the storage contents of the storage means .
Setting means for setting the required value of the start timing, and a torque-reduction control means for performing torque reduction at the start timing corresponding to the required value during shifting, the setting means
Indicates that the air-fuel ratio at the time of shifting from the high gear to the low gear is lean.
When the air-fuel ratio is rich
Later than the start timing of torque down at
A control device for an automatic transmission, wherein the control device is configured as follows . 2. The power transmission path of a multi-stage transmission mechanism is changed.
Switch gears and change the torque of the engine during shifting.
Automatic change to reduce torque temporarily
The operating state that detects the operating state of the engine in the high speed gear
Detecting means and an engine according to the output of the operating state detecting means.
Air-fuel ratio setting that sets the air-fuel ratio of the mixture supplied to the gin
Means and a value related to the amount of torque reduction according to the air-fuel ratio
And the value related to the start timing of torque down.
Based on the storage contents of the storage means.
Required value of torque reduction amount and torque down according to air-fuel ratio
Setting means for setting the required value of the start timing of the
The torque reduction amount and start tie
Torque-down control means for performing torque-down by
Wherein the setting means is provided when shifting from a high gear to a low gear.
When the air-fuel ratio of the
Make it smaller than when rich and open torque down.
It is configured to delay the start timing.
Control apparatus for an automatic transmission according to symptoms.