JP3112705B2 - Transmission 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 automatic transmission, and more particularly, to a shift control device for an automatic transmission which may execute a power-on downshift by clutch-to-clutch shift.

[0002]

BACKGROUND OF THE INVENTION In order to achieve a particular shift in an automatic transmission, it is often necessary to simultaneously engage and disengage two frictional engagement devices (a so-called clutch-to-clutch shift). In this case, if the synchronization and disengagement of the respective friction engagement devices are not properly synchronized, the gear train of the automatic transmission instantaneously becomes rigid or neutral, and the output shaft torque is reduced. Problems such as a sudden descent and engine spouting occur.

Therefore, in the case of such a clutch-to-clutch shift, it is ideally desirable that the engagement and disengagement be simultaneously started and ended simultaneously.

[0004]

However, in the conventional clutch-to-clutch shift control, especially during a power-on downshift in a low-load / low-speed range (when the accelerator pedal is depressed, the power moves from the engine side to the wheel side). Downshift that is carried out in the transmitted state)
Since the shift time is too short, the engagement of the friction engagement device on the low speed side (the brake B1 in the embodiment described later) cannot be made in time, and there is a problem that the engine is easily blown up.

Therefore, conventionally, in order to prevent this, shifting in this region has been avoided. That is, for example, the downshift line from the third speed to the second speed is shifted to the higher load side (Toyota Motor: 1978-4 Automatic Transmission (A40) Repair Letter).

However, if the downshift line is shifted to the high load side, the downshift will not be performed unless it is inevitably stepped down, and there is a problem that the acceleration is reduced accordingly.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and has been made in view of executing clutch-to-clutch shift satisfactorily and preventing engine injection.
The object of the present invention has been achieved by providing a shift control device for an automatic transmission having excellent acceleration characteristics.

[0008]

SUMMARY OF THE INVENTION As shown in FIG. 1, the present invention provides an automatic transmission for executing a power-on downshift by a clutch-to-clutch shift according to a shift point set in advance according to a vehicle condition. in the shift control apparatus, when executing the downshift, the engine output reduction means for reducing the engine output, the clutch to
In performing a downshift by clutch, the
Reduce the hydraulic pressure supply speed to the engagement-side frictional engagement device
Quick supply control means for executing a quick supply control for increasing the supply speed compared to the supply speed during a shift other than a shift , and quick supply availability detection means for detecting whether or not the quick supply control is not executable Detected that the quick supply control can not be executed.
When issued, than when viable, by which an output reduction amount setting means for increasing the amount of reduction in the engine output when executing the downshift is obtained by solving the above problems .

[0009]

According to the present invention, when the power-on downshift of the clutch-to-clutch shift is performed, the problem caused by the shift time being too short and the engagement of the friction engagement device on the low speed side being unable to be made in time cannot be solved. When this shift is performed, the engine output is reduced, and the hydraulic pressure is quickly supplied to the clutch on the engagement side by a hydraulic circuit. Here, "quick supply"
(At the time of shifting other than the downshift), hydraulic pressure is applied to the clutch.
Supply hydraulic pressure at a higher speed than
U.

When the engine output is reduced, the release of the high-speed side frictional engagement device is delayed, and the engagement of the low-speed side frictional engagement device is accelerated, so that the above problem can be adjusted. Therefore, even when the shift point is shifted to the (regular) low load side with emphasis on acceleration, together with the quick supply control of the hydraulic pressure, the engagement of the friction engagement device on the low speed side cannot be made in time. Can be prevented.

By the way, it is considered that the quick supply of the hydraulic pressure by the hydraulic circuit is not always executable, and sometimes the quick supply of the hydraulic pressure cannot be performed.

For example, when a solenoid valve for controlling a valve related to the hydraulic circuit fails, or when the timing of switching the valve by the solenoid valve is determined from the rotation state of a specific member, the member is not operated. If a failure occurs in the sensor system for detecting the rotation speed, quick supply of the hydraulic pressure cannot be appropriately performed.

As described above, when the hydraulic pressure cannot be quickly supplied ( when the pressure is restricted) , the power-on downshift by the clutch-to-clutch shift is performed while the shift point is set to the low load side. If the shift pattern is executed, there arises a problem that the engagement of the low-speed side frictional engagement device cannot be made in time, causing a shock and causing the engine to blow up.

According to the present invention, in order to cope with this point, basically, while the speed change point is maintained on the (regular) low load side and the acceleration performance is ensured, the hydraulic pressure is quickly supplied by the hydraulic circuit. First detect whether it is in a feasible state,
Under conditions where quick supply of hydraulic pressure is feasible, a combination of weak engine torque reduction is used to execute a power-on downshift by clutch-to-clutch shifting to ensure further acceleration, while quick supply of hydraulic pressure is restricted Under this condition, the engine is more strongly reduced to prevent the engine from blowing up.

[0015]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 2 is an overall schematic diagram of an integrated control device for an automatic transmission and an engine to which the present invention is applied.

The engine 1 is controlled by an engine control computer 7 by an injection valve 19.
And the ignition timing at the distributor 20 are controlled, and an engine output corresponding to the accelerator opening (operating amount) of the accelerator pedal 22 and the engine speed is obtained.

That is, the intake pipe 24 of the engine 1 is provided with a throttle valve 26 that opens and closes in conjunction with the movement of the accelerator pedal 22.

The automatic transmission 2 is controlled by the automatic transmission control computer 8 to operate the solenoid valves S1 to S1 of the hydraulic control device 3.
S3 is controlled, and as a result of the change of the oil passage in the hydraulic control device 3, the engagement state of each friction engagement device is selectively changed,
The shift speed can be obtained according to the shift pattern shown in FIG. 7A corresponding to the vehicle speed and the accelerator opening. In this shift pattern, the downshift line from the third speed to the second speed in the power-on region where the load is low and the vehicle speed is particularly low is lower than that of the conventional shift pattern (FIG. 7B). Is set to

The engine control computer 7 has an engine rotation speed detected by an engine rotation sensor 9, an intake air amount detected by an intake air amount sensor 10, and an intake air temperature sensor 1.
1, signals of an intake air temperature by an accelerator pedal 1, an accelerator opening by an accelerator opening sensor 12, a vehicle speed by a vehicle speed sensor 13, a catalyst temperature by a catalyst sensor 14, and a brake ON by a brake switch 15.

The engine control computer 7 determines the fuel injection amount and the ignition timing based on these signals. In this embodiment, the engine output (engine torque) is reduced by a well-known ignition timing retard. However, the present invention does not limit how to reduce the engine output. For example, a method of reducing the fuel injection amount or a method of providing a sub-throttle valve and controlling this by a motor may be used.

On the other hand, the automatic transmission control computer 8 includes the accelerator opening sensor 12 and the vehicle speed sensor 1.
3. In addition to the signals from the catalyst sensor 14, the brake switch 15, etc., the position of the shift lever by the shift position sensor 16, the travel selection pattern such as the fuel efficiency-oriented travel or the power performance-oriented travel by the pattern select switch 17, the overdrive switch 18 A signal for permitting a shift to overdrive is input by the solenoid valve S so that a gear corresponding to the vehicle speed and the accelerator opening is obtained.
1 to S3 are ON-OFF controlled.

FIG. 3 shows a transmission section of the automatic transmission 2. This transmission unit includes a torque converter 120, an overdrive mechanism 140, and an underdrive mechanism 160.

The torque converter 120 includes the pump 1
21, a turbine 122, and a stator 123, and includes a lock-up clutch 124.

The overdrive mechanism 140 includes a planetary gear set including a sun gear 143, a planetary pinion 142 meshing with the sun gear 143, a carrier 141 supporting the planetary pinion 142, and a ring gear 144 meshing with the planetary pinion 142. Prepared,
The rotational state of the planetary gear unit is controlled by a clutch C0, a brake B0, and a one-way clutch F0.

The underdrive mechanism 160 includes a common sun gear 161, planetary pinions 164 and 165 meshing with the sun gear 161, and the planetary pinion 1
Ring gear 1 meshing with carriers 166 and 167 supporting planet 64 and 165 and planetary pinions 164 and 165
62, 163. The planetary gear set includes two sets of clutches C1, C2 and a brake B which determine the rotational state of the planetary gear set and the state of connection with the overdrive mechanism 40.
1, B3 and one-way clutch F2.

Each gear is achieved by engaging the clutches C0, C1, C2 and the brakes B0, B1, B3 as shown in FIG. 4 (indicated by a circle in FIG. 4). At this time, the one-way clutches F0 and F2 are operated (locked) at the time of driving (when power is transmitted from the engine to the wheels) at the position indicated by the mark ◎ in FIG.

Here, the downshift from the third gear to the second gear is a so-called "clutch-to-clutch shift" in which the brake B1 is engaged and the clutch C2 is released. Therefore, in this embodiment, the present invention is applied to the clutch-to-clutch shift from the third speed to the second speed when the power is turned on, particularly in a low load / low speed region.

FIG. 5 shows a hydraulic circuit for executing a quick supply of hydraulic pressure to the brake B1 during the gear shift.

In the figure, reference numeral 200 denotes a 3 → 2 timing valve for realizing quick supply, 210 denotes an orifice, 220 denotes a 2-3 shift valve, and 230 denotes a B1 accumulator valve.

The 2-3 shift valve 220 is switched between the second speed state and the third speed state by switching the solenoid valve S1 when the 1-2 shift valve (not shown) is in the high speed state. Is used to change over.

Here, the normally closed type solenoid valve S1 is adopted, and when the solenoid valve S1 is turned from off to on, the 2-3 shift valve 220 is shifted to the third shift valve 220.
The state is shifted from the state of the second gear to the state of the second gear, and as a result, the hydraulic pressure to the brake B1 is output. The hydraulic pressure applied to the brake B1 is 2-
The configuration generated by the three-shift valve 220 is exactly the same as the conventional one.

The oil pressure to the brake B1 generated at the time of shifting from the third speed to the second speed in this manner is applied to the oil passage A1.
And A2 and A3 through the ports 201 and 202 (and 20) of the 3 → 2 timing valve 200, respectively.
3).

At first, the solenoid valve S3 is turned off, and no hydraulic pressure is generated at the port 204 (because it is a normally closed type), so the spool 20 of the 3 → 2 timing valve 200 is operated by the hydraulic pressure applied to the port 202.
Reference numeral 6 denotes a state in the lower half of the figure, that is, a state in which the port 201 is closed. Therefore, the hydraulic pressure is supplied to the brake B1 only from the oil passage A3 side.

The supply of the hydraulic pressure through the route of the oil passage A3 is started slowly by the function of the B1 accumulator 230, so that the brake B1 is slowly applied.

Here, when the solenoid valve S3 is turned on, hydraulic pressure is generated at the port 204, and the spool 206 is brought into the upper half state in FIG. As a result, ports 201 and 20
Thus, the hydraulic pressure in the oil passage A1 is supplied to the brake B1 not only through the oil passage A3 but also through the oil passage A2. As a result, B2 is engaged very quickly.

In this embodiment, the solenoid valve S3 is turned off.
The on-timing is monitored by monitoring the engine rotation speed, and is performed when the rotation speed approaches the synchronous rotation speed in the second speed. Therefore, it is possible to minimize the shock due to the synchronization deviation irrespective of various variations.

FIG. 6 shows a specific control flow of the downshift control of the power-on clutch-to-clutch from the third speed to the second speed.

First, in step 310, various signals are read. Specifically, for example, the accelerator opening θ, the vehicle speed V, the catalyst temperature S, and the like are read.

In step 320, it is determined whether a downshift from the third speed to the second speed has been determined.
This control is not executed when the downshift from the third speed to the second speed is not performed, so that the process returns.

In step 330, it is determined whether or not the power-on downshift is in a low load / low speed range. This determination is made based on the vehicle speed and the accelerator opening at that time. If the power is not low-load / low-speed area power-on / down, this control is not executed, and therefore, the process returns.

This is mainly due to the following reasons.

In general, when the load is low, the torque applied to each friction engagement device is small, so that the line pressure generated in the automatic transmission is also low. On the other hand, there is a situation that the shift time is not reduced so much (because the line pressure is low). As a result, the problem to be solved by the present invention is more likely to occur at lower load.

On the other hand, even at a low vehicle speed, the change in the engine speed when shifting from the third speed to the second speed is small, so that the shift is immediately terminated. As a result, the problem to be solved by the present invention is solved. Is easy to occur.

In sum, it is in the low load / low vehicle speed region that the present invention functions particularly effectively.

That is, when the load is high or the vehicle speed is high, the third
It takes a relatively long time to shift from the second gear to the second gear, and it is unlikely that a problem such as the engagement of the brake B1 being missed will occur. Therefore, in such a case, it is not necessary to reduce the engine output or execute the quick supply control. Rather, it is better not to reduce the engine output as much as possible in view of the nature of the power-on downshift, that is, the shift executed when the driver desires more driving force. From the viewpoint of minimizing the occurrence of a state in which the accelerator opening and the engine output do not correspond to each other, it is preferable not to reduce the engine output except when necessary.

Further, since there is a possibility that a speed change shock may occur due to a sudden engagement in the quick supply of hydraulic pressure, it is desirable not to execute the quick supply control unless necessary. Therefore, in this embodiment, the application of the present invention is limited to a low load / low vehicle speed region.

At step 340, a shift signal (switching signal for the solenoid valve S1) for switching from the third speed to the second speed is output.
e monitoring is started. This monitor detects the start time of the engine output reduction control and the start time of the quick supply of the B1 hydraulic pressure.

In step 360, flag F is set to 1
Is determined. This is a step for detecting whether or not the quick supply of the B1 oil pressure is regulated. When the B1 hydraulic pressure cannot be supplied quickly for the above-described reason, the flag F is set to 1 by a separate diagnosis flow, and the value is read here. When quick supply control can be normally executed, it is determined that F = 1,
Proceed to step 370.

Since the B1 hydraulic pressure cannot be supplied quickly even when the transmission oil temperature is low, the flag F may be set to 1 at this time as well.

At step 370, the engine speed Ne is calculated.
Is the vehicle speed V (output shaft rotation speed N0) and the gear ratio i2 of the second speed stage
Is determined to be greater than a value obtained by subtracting a constant N1 from a value obtained by multiplying the constant by N. When this condition is satisfied, the routine proceeds to step 380, where the timer T1 is reset to 0, and further, at step 390, the engine output reduction control by retarding the ignition timing is started. At this time, the retard amount d1 is relatively small, and therefore the engine output is slightly reduced.

At the same time (in step 400), a quick supply command of the hydraulic pressure of the brake B1, ie, an OFF → ON command of the solenoid valve S3, is issued, and the brake B1 is immediately engaged by the hydraulic circuit described above.

The control for reducing the engine output is performed in step 41.
When the timer T1 reaches 0, it is determined that the timer T1 has reached the predetermined value Tr.
To end.

On the other hand, if it is determined in step 360 that the flag F is 0, that is, it is determined that the quick supply of hydraulic pressure is restricted, the routine proceeds to step 430, where the engine rotation speed Ne is reduced to the vehicle speed V (the output shaft rotation speed N0). ) Is multiplied by the gear ratio i2 of the second speed, and it is determined whether or not the value is greater than a value obtained by subtracting a constant N2 (N1 <N2). Here, the reason why the constant N2 is set to be larger than N1 is to execute the reduction of the engine torque from an earlier stage because the quick supply control of the hydraulic pressure is restricted.

When the condition at step 430 is satisfied, the routine proceeds to step 440, where the timer T2 is reset to zero. At step 450, the reduction of the engine output due to the retardation of the ignition timing is started. At this time, the retard amount d2 is set to a value larger than the above-mentioned d1, so that the engine output is considerably reduced. As a result, it is possible to prevent the problem that the brake B1 cannot be engaged in time even though the quick supply control of the B1 hydraulic pressure is restricted.

This engine torque reduction is continued until the timer T2 reaches a predetermined value Ts (Tr <Ts). When the count is counted up, the routine proceeds to step 420, where the reduction of the engine output is ended.

FIG. 8 shows various characteristics when the above embodiment is executed.
It is qualitatively shown the diagram sex.

Conventionally, since neither quick supply control of the brake B1 hydraulic pressure nor reduction of engine torque is executed, the engine spouts up and the output shaft torque drops (broken line). Then, it can be suppressed well (solid line).
Also, in the event that the quick supply control of the B1 hydraulic pressure is restricted, the engine output is further reduced, so that the engine is prevented from being blown up as well (dotted line).

In this embodiment, the change of the shift point is
I was trying to do it only at low load and low vehicle speed,
In the present invention, the shift point of the power-on downshift of the clutch-to-clutch shift may be changed in the entire range from the purpose.

However, in this case, for example, when the load is low and the vehicle speed is low, it is preferable that the amount of reduction of the engine output is increased.

[0061]

As described above, according to the present invention, when performing a downshift by clutch-to-clutch shift, the engine output is reduced and the hydraulic pressure is quickly supplied to prevent the engine from rising. At the same time, since the shift point can be shifted to the low load side, an excellent effect that acceleration performance can be improved can be obtained.

Further, even in a state where the quick supply control cannot be executed, the effect that the engine output can be effectively prevented from being increased because the engine output reduction amount is changed. Can be

[Brief description of the drawings]

FIG. 1 is a block diagram showing the gist of the present invention.

FIG. 2 is an overall schematic view of a vehicle automatic transmission and an engine to which an embodiment of the present invention is applied.

FIG. 3 is a skeleton diagram showing a gear train of the automatic transmission.

FIG. 4 is a diagram showing an engagement state of a friction engagement device of the automatic transmission.

FIG. 5 is a main part hydraulic circuit diagram for executing quick supply control of brake B1 hydraulic pressure.

FIG. 6 is a flowchart showing a control flow executed by the apparatus of the embodiment.

FIG. 7 is a diagram showing an example of a shift pattern adopted in the control flow of FIG. 6;

FIG. 8 is a shift characteristic diagram qualitatively showing the effect of the embodiment of the present invention.

[Explanation of symbols]

 B1: engagement side friction engagement device, C2: release side friction engagement device, 22: accelerator pedal, 26: main throttle valve, 28: motor, 12: accelerator opening sensor, 13: vehicle speed sensor, 200: 3- 2 timing valve, 201-204 ... port, 206 ... spool.

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁷ Identification code FI F16H 61/06 F02P 5/15 B // F16H 63:40 (72) Inventor Yasuo Hojo 1st Toyota Town, Toyota City, Aichi Prefecture Toyota Motor (72) Inventor Masahiro Hayabuchi 10 Takane, Fujiimachi, Anjo, Aichi Prefecture Inside Aisin AW Co., Ltd. (72) Masahiko Ando 10, Takane, Fujiimachi, Anjo, Aichi Prefecture Aisin Ai (72) Inventor Kazumasa Tsukamoto 10 Takane, Fujii-machi, Anjo-shi, Aichi Prefecture Inside Aisin AW Co., Ltd. (56) References JP-A-63-17130 (JP, A) JP-A-62 -99225 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B60K 41/04-41/18 F02D 29/00 F02D 41/04 F02P 5/15 F16H 61/00

Claims (1)

(57) [Claims] 1. A shift control device for an automatic transmission that executes a power-on downshift by clutch-to-clutch shift according to a shift point set in advance according to a vehicle state. Means for reducing engine output, and the speed of supplying hydraulic pressure to the engagement-side frictional engagement device when performing a downshift by the clutch-to-clutch shift.
Degree to the supply speed at the time of shifting other than the downshift.
And quick supply control means for executing a quick supply control for fast base, and a quick supply availability detecting means for the quick supply control detects whether infeasible, when said quick supply control is detected impossible executed, Compared to when it is possible to execute the downshift,
Shift control device for an automatic transmission, characterized by comprising, an output reduction amount setting means for increasing the amount of reduction in the engine output.