JPH0544825A - Output shaft torque controller of automatic transmission - Google Patents

Abstract

PURPOSE:To stabilize control responsiveness of output shaft torque of a transmission by means of ignition timing feedback control at the time of changing speed by variably setting control operational quantities such as a proportional constant, a differential constant, etc., in response to engine load, and calculating a delay angle control quantity based on those controlled operational quantities. CONSTITUTION:An operation condition detecting means is formed of, for example, a throttle sensor 8, a crank angle sensor 9, and a vehicle speed sensor 11. The target torque of a transmission output shaft 10 during speed change is set by a control unit 6 based on an engine operation condition detected at the time of starting the speed change, a gear ratio before and after the speed change and a target speed change time. And engine ignition timing during speed change is feedback-controlled so that the torque of the transmission output shaft 10 detected by a torque detection means 12 may become close to the target torque. An operation quantity at an ignition timing is varied according to the engine operation condition. Consequently, even if the engine operation condition is varied, the torque can be varied by specified responsiveness.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an output shaft torque control device for an automatic transmission, and more particularly to a device for suppressing shift shock by feedback controlling the ignition timing of an engine during a shift.

[0002]

2. Description of the Related Art Conventionally, as a gear shift shock reducing device for an automatic transmission for an automobile, a rapid change in the transmission output shaft torque at the time of gear shifting is achieved by retarding the ignition timing of the engine to reduce the engine output torque. There is a device which suppresses the shift shock to reduce the shock (for example, Japanese Patent Application No. 1-3).
25798, etc.).

In the conventional gear shift shock reducing apparatus based on the ignition timing retard control, the engine output torque down request is generated when the throttle valve opening TVO at that time is within a predetermined range. When the torque down request is generated, the ignition timing is retarded by a preset retard amount corresponding to the throttle valve opening region, and the engine output shaft torque is reduced to reduce the torque of the automatic transmission output shaft. I try to curb change.

[0004]

However, in the conventional device, the ignition timing is not controlled based on the actual transmission output shaft torque during gear shifting, but the ignition timing is delayed by the throttle valve opening TVO during gear shifting. This is an open control method in which the angle amount is uniquely set, and the same retard angle amount is set for the throttle valve opening region having a certain range. Therefore, it cannot be said that the transmission output shaft torque control accuracy during shifting is sufficient, and the effect of reducing shift shock is not sufficient.

Therefore, in order to smoothly change the output shaft torque of the transmission from before the shift to after the shift, the applicant sets a target torque of the transmission output shaft during the shift and shifts the gear during the shift. A device was proposed in which the ignition timing of the engine is feedback-controlled so that the detection value of the sensor for detecting the output shaft torque of the machine approaches the target torque (Japanese Patent Application No. 3-1090).

However, even during the same gear shift from the first speed to the second speed, for example, the responsiveness of the engine torque change and the torque change amount due to the feedback control of the ignition timing differ depending on the engine load at that time, and the engine load changes. Depending on the situation, it may not be possible to ensure the ability to follow the target torque or hunting of the transmission output shaft torque may occur, making it difficult to perform stable feedback control of the transmission output shaft torque during gear shifting.

FIG. 9 shows a response delay time which is a feedback control time required to obtain a predetermined torque reduction amount with a constant ignition timing retard correction amount, and how the response delay time depends on engine load (boost pressure). This is the result obtained by an experiment as to whether it changes. As is clear from FIG. 9, when the engine is under high load, the amount of change in the engine output torque per ignition timing correction amount is large, so the response of the engine output torque change due to ignition timing control is good, and conversely, When the load is low, even if the same ignition timing correction amount is given, the change in the engine output torque is small, so the responsiveness deteriorates.

The present invention has been made in view of the above circumstances. In the feedback control of the ignition timing for smoothly changing the output shaft torque of the transmission at the time of shifting, even if the engine operating condition changes, the desired result is obtained. The purpose is to be able to change the torque with responsiveness.

[0009]

Therefore, an output shaft torque control device for an automatic transmission according to the present invention is configured so that an engine torque is transmitted to a transmission mechanism via a torque converter. The torque control device is configured as shown in FIG. In FIG. 1, the target torque setting means sets at least the engine operating state detected by the engine operating state detecting means at the start of gear shifting, the gear ratio before and after shifting of the automatic transmission detected by the gear ratio detecting means, and the target shift time. Based on this, the target torque of the transmission output shaft of the transmission output shaft after shifting is set.

The ignition timing feedback control means feedback-controls the engine ignition timing during shifting so that the torque of the transmission output shaft detected by the torque detecting means approaches the target torque. Here, the control operation amount varying means changes the operation amount of the ignition timing in the ignition timing feedback control means in accordance with the engine operating state.

[0011]

In other words, even if the ignition timing is controlled by the same angle, the change in the engine output torque obtained in response to this will vary depending on the engine operating state at that time, and the responsiveness to the target torque will vary. Therefore, when performing the feedback control of the ignition timing, the control operation amount is changed according to the engine operating state, and even if the engine operating state varies, the feedback control to the target torque can be performed with a constant response characteristic. I was able to do it.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In FIG. 2 showing the configuration of this embodiment, an automatic transmission 2 is connected to the output side of the engine 1. Automatic transmission 2
Is a hydraulic torque converter 3 interposed on the output side of the engine 1, a gear type transmission 4 connected via the torque converter 3, and a coupling / release operation of various transmission elements in the gear type transmission 4. And a hydraulic actuator 5 for performing. The hydraulic pressure for the hydraulic actuator 5 is ON / OFF controlled via various electromagnetic valves (not shown).

Signals from various sensors are input to the control unit 6. As the various sensors, a throttle sensor 8 for detecting the opening TVO of the throttle valve 7 of the intake system of the engine 1 is provided. A crank angle sensor 9 is provided on the crankshaft of the engine 1 or a shaft that rotates in synchronization with the crankshaft. The signal from the crank angle sensor 9 is, for example, a pulse signal for each reference crank angle, and the engine rotation speed N is calculated from the period.

A vehicle speed sensor 11 for detecting a vehicle speed VSP by obtaining a rotation signal from the output shaft 10 of the automatic transmission 2 is provided. Further, a torque sensor 12 is provided which is attached to the output shaft 10 of the automatic transmission 2 and serves as torque detection means for detecting the output shaft torque TRQ of the transmission 2. The control unit 6 includes, for example, a CPU for engine control (fuel injection control and ignition timing control) and a CP for automatic transmission control.
It is an integrated type that incorporates U and uses a dual port RAM that can be accessed by both CPUs. With such a configuration, the data calculated by both CPUs can be shared.

The automatic transmission control CPU of the control unit 6 is based on the operation position signal of the select lever operated by the driver, for example, when the select lever is in the D range, the first speed according to the throttle valve opening TVO and the vehicle speed VSP. Automatic shift control is performed to automatically set the shift position of the fourth speed and control the gear type transmission 4 to the shift position via the hydraulic actuator 5.

That is, a shift pattern map is set in advance based on the throttle valve opening TVO representing the engine load and the vehicle speed VSP, and corresponds to the actual opening TVO and the vehicle speed VSP detected by the sensor. The shift position is referred to from the shift pattern map, and when the current shift position is different from the shift position corresponding to the driving condition obtained from the map, the shift position is changed to the shift position referred to in the map. is there.

Next, the control operation of the transmission output shaft torque during shifting according to this embodiment will be described with reference to the flowcharts of FIGS. 3 and 4. In this embodiment, the functions of the gear ratio detecting means, the target torque setting means, the ignition timing feedback control means, and the control operation amount varying means are provided by software as shown in the flow charts of FIGS. 3 and 4. ing.

First, step 1 (indicated as S1 in the figure,
The same applies hereinafter), the value of the control start flag F is determined. As will be described later, the flag F is set to 1 when the start of a shift operation is detected, and reset to 0 when the shift time ends. When the flag F is 0, the routine proceeds to step 2, where it is judged whether the shift operation is started (inertia phase). For example, the output shaft torque of the transmission suddenly decreases when the clutch is disengaged at the start of the gear shift and then rapidly increases when the clutch is engaged. Therefore, the start of the gear shift operation can be determined by detecting such a torque change.

If it is determined in step 2 that the gear shift operation has not started, this routine is ended. When it is determined in step 2 that the shift operation is started, the control start flag F is set to 1 in step 3 and the timer T for measuring the elapsed time after the start of the shift operation is reset to 0, and then the process proceeds to step 4. An initial value of a basic control amount RETIN and a target shift time t in ignition timing control, which will be described later, are set. As shown in FIG. 5, these values correspond to the gear ratio G before shifting according to the type of shift (first speed → second speed, second speed → third speed, etc.).
Gear ratio GR obtained from b and gear ratio Ga after shifting
Using (= Ga / Gb) and the throttle valve opening TVO as parameters, a map is set in which the initial value of the basic control amount RETIN and the target shift time t are stored in advance.

When the flag F is set to 1 in step 3 at the start of the gear shift operation as described above, from the next time onward,
When the flag F is determined to be 1 in step 1, the process proceeds to step 5. In step 5, it is determined whether or not the value of the timer T that measures the elapsed time after the start of the gear shifting operation has reached the target gear shifting time t set in step 4.

Then, when the value of the timer T has reached the target shift time t, it is judged that the shift has been completed, the flag F is reset to 0 in step 6, and this control is ended. On the other hand, when the value of the timer T has not reached the target shift time t, the shift is in progress, so the routine proceeds to step 7, where the basic control amount RET initialized at step 4 is set.
Since IN is gradually increased with the lapse of time T after the start of the gear shift operation, it is updated with a value obtained by adding ΔRETIN (> 0).

After step 4 or step 7, the process proceeds to step 8. In step 8, the target torque TRQREF of the transmission output shaft during shifting is set. Specifically, based on the gear ratio before and after the shift and the engine speed N at the start of the shift, the engine speed Naf after the shift when the vehicle speed VSP is kept constant is obtained. Then, as shown in FIG. 6, referring to a map in which the relationship between the engine speed N, the throttle valve opening TVO and the torque is preset, the throttle valve opening TVO is also kept constant during the shift. Assuming
A torque TRQst corresponding to the engine rotational speed N immediately before the shift and a target torque TRQend after the shift are respectively obtained.

Here, the target torque TRQREF during shifting, which changes with the lapse of time from the start of shifting, is set so as to change from the pre-shifting torque TRQst to the post-shifting torque TRQend at a constant rate at the target shifting time t. It is updated and set each time based on the elapsed time T from. However, the torque TRQst at the start of the shift may be a value detected by the torque sensor 12 instead of the value retrieved from the map as shown in FIG. Further, the torque detected by the torque sensor 12 at the start of the shift is compared with the torque obtained by referring to the map of FIG. 6 from the operating state at the start of the shift, and the post-shift obtained from the map based on the comparison result. The target torque may be corrected.

The gear ratio before and after gear shifting is set in accordance with the throttle valve opening TVO and the vehicle speed VSP.
It is obtained from the pattern of the speed change position. Therefore, the gear ratio detecting means is composed of a map in which the shift position pattern is set and a search function from the map. Further, as described above, the target torque is set based on the engine rotation speed N, the throttle valve opening TVO, and the vehicle speed VSP at the start of gear shifting. Therefore, the operating state detecting means in this embodiment is the throttle sensor 8 , The crank angle sensor 9 and the vehicle speed sensor 11 correspond to each other.

In step 9, the deviation TRQERR (= TRQ-TR) between the output shaft torque TRQ of the transmission detected by the torque sensor 12 and the target torque TRQREF which changes with the elapsed time T during the shift set in step 8.
QREF) is calculated. Here, it is desirable that the output from the torque sensor 12 is not subjected to A / D conversion as it is and used, but a signal value excluding a high frequency component (for example, 40 Hz or more) is used by a low pass filter. this is,
If the response of the ignition timing is 20 Hz or less and the ignition timing is controlled based on the torque detection signal including the high frequency component,
This is because hunting occurs due to the delay in response.

In step 10, a value CUTCYL indicating the number of cylinders for which the fuel supply is stopped in the fuel supply cylinder number control which is performed in parallel with the ignition timing control at the time of shifting according to the present invention.
Is reset to 0. In step 11, it is determined whether or not the engine is in a high output region suitable for controlling the number of fuel supply cylinders.
It is determined by the value of the output mixture ratio correction coefficient KMR. The output mixture ratio correction coefficient KMR is a coefficient for correcting the basic fuel injection amount Tp in the fuel supply control to the engine, and is 0 in the high load / high speed region of the engine where high output is required.
It is assumed that the basic fuel injection amount Tp is set to a positive value exceeding 0 and the basic fuel injection amount Tp is increased and corrected, and it is set to 0 in other operating regions and the basic fuel injection amount Tp is not corrected.

When it is judged in step 11 that KMR = 0, it is in a region other than the high output region. In this case, the ignition timing control is executed by jumping to step 15 without controlling the number of fuel supply cylinders. However, in the high output region where KMR ≠ 0, the process proceeds to step 12. In step 12,
The deviation TQRERR calculated in step 9 is compared with a predetermined torque amount TRQDWN.

When TQRERR> TRQDWN, it is determined that the torque deviation is large enough to increase the number of cylinders for which the fuel supply is stopped, and the routine proceeds to step 13, where the value CUTCYL indicating the number of cylinders for which the fuel supply is stopped is set. After counting up, proceed to step 14. In step 14,
The torque amount TD1CYL estimated to decrease when the number CUTCYL of fuel supply stopped cylinders is increased by 1 is calculated by the deviation TQ.
After updating the deviation TQRERR with the value subtracted from RERR, the process returns to step 12 and the same determination is performed again. In this way, when TQRRRR≤TRQDWN, the routine proceeds to step 15, where ignition timing control is executed.

That is, when the fuel supply is stopped, fine torque control cannot be performed, but the torque can be greatly reduced. Therefore, when the deviation of the actual torque TRQ from the target torque TRQREF is large, the large torque is stopped by stopping the fuel supply. By reducing the torque, a relatively small torque deviation with respect to the target is controlled by the ignition timing control.

In step 15, the ignition timing (ignition advance value)
The control constants (proportional constant K _p , integral constant K _i , differential constant K _D ) for controlling the retard control amount RETAT of the throttle valve opening TVO and the like are controlled in accordance with the deviation TQRERR. Variable setting. Then, in the next step 16, the ignition timing retard control amount RETAT is calculated according to the following equation using the control constant set in step 15.

RETAT = K _p · TRQERR + K _i ∫ TRQERR + K _D · d / dt (TRQERR) + RETIN That is, the basic control amount RE as the feedforward amount.
Based on TIN, proportional component K _p · TRQERR and integral component K _i
∫ TRQERR, derivative K _D · d / dt (TRQER
The feedback control is performed with a correction amount obtained by adding (R), and by giving the basic control amount, it is possible to perform ignition timing control with good response from the start of gear shift and reduce gear shift shock as much as possible. It is made possible (see FIG. 7).

Further, the basic control amount RETIN is gradually increased in step 7 as the gear shift elapsed time increases, whereby the load of the feedback correction amount can be reduced and the stability of the footback control can be improved.
Further, in the present embodiment, as described above, in step 15, as shown in FIG. 8, the proportional constant K _p , the integral constant K _i , and the differential constant K _D (control operation amount) are changed according to the engine load. Is done. That is, when the engine load state is different, the time required to obtain a predetermined torque reduction amount when controlled with the same constant (operation amount) is different, and the higher the load, the higher the responsiveness, and conversely, the low load. Since the responsiveness sometimes deteriorates, the proportional constant K _p , the integral constant K _i , the derivative used in the setting control of the retard angle control amount RETAT are controlled so that the torque can be feedback-controlled with a constant response characteristic even if the engine load changes. The control operation amount such as the constant K _D is changed according to the engine load.

As described above, if the manipulated variable of the ignition timing control is changed according to the engine load, it is possible to approach the target torque with a constant response characteristic, and the followability to the target torque deteriorates, or conversely. It becomes possible to prevent hunting from occurring due to control overshoot, and it is possible to control the transmission output shaft torque to a target with a constant response characteristic even if the engine load changes. By doing so, it is possible to stably exert the effect of mitigating the shift shock.

The engine load is the throttle sensor 8
Although it can be represented by the throttle valve opening TVO detected by the above, the basic fuel injection amount Tp calculated for fuel supply control in the fuel control CPU may be used.
Furthermore, when a sensor for detecting boost pressure (negative suction pressure) is provided, the boost pressure may be used. Further, in the setting of the retard angle control amount RETAT, the proportional / integral / derivative control (PID control) is performed, but the retard angle control amount RETAT may be set by proportional control, integral control, or proportional / integral control. That is clear.

In step 17, it is judged whether or not the feedback control of the ignition timing is executed for the first time (for example, it can be judged by whether or not the control start flag F is judged from 0 to 1). Then, when it is determined that it is the first time, the process proceeds to step 18, and based on the retard control amount RETAT set by the addition of the feedback correction amount and the feedforward amount (basic control amount RETIN) in step 16,
The data under the same condition of the map storing the initial value of the basic control amount RETIN is rewritten. Meanwhile, step
When it is determined in 17 that it is the second time or later, step 18 is jumped to step 19.

In this way, by learning and modifying the initial value of the basic control amount RETIN to a value corresponding to the result of the initial feedback control, the engine rotational speed N and the target torque TRQREF are changed as the clutch friction coefficient changes with time. Even if the correlation is deviated, good feedback control performance can be maintained by modifying the basic control amount RETIN.

In step 19, the fuel supply to the number of cylinders indicated by CUTCYL is stopped. However, when it is 0, there is no fuel supply stopped cylinder. Step 20, step
The ignition timing is retarded by the retard control amount RETAT set in 16. In the present embodiment, as described above, the torque control during the shift is performed even when the fuel supply is stopped, but only the feedback correction of the ignition timing may be performed.

Further, the ignition timing may be retarded only by the feedback correction amount without using the basic control amount RETIN.

[0039]

As described above, in the feedback control of the ignition timing for obtaining the target torque during the gear shift, the operation amount of the feedback control is changed based on the engine operating state, so that the engine operating state is Even if it changes, the transmission output shaft torque can be controlled with a constant response characteristic, so that the target torque can be stably obtained, and the effect of reducing gear shift shock can be satisfactorily obtained. It will be possible.

[Brief description of drawings]

FIG. 1 is a block diagram illustrating a configuration of the present invention.

FIG. 2 is an overall system configuration diagram of an embodiment of the present invention.

FIG. 3 is a flowchart of a torque control routine of the above embodiment.

FIG. 4 is a flowchart of a torque control routine of the above embodiment.

FIG. 5 is a diagram showing a map of a basic control amount of ignition timing and a target shift time of the embodiment.

FIG. 6 is a diagram illustrating setting of a target torque according to the embodiment.

FIG. 7 is a time chart showing a characteristic of an ignition timing retarding control amount at the time of shifting according to the embodiment.

FIG. 8 is a diagram showing a map of feedback control constants according to the embodiment.

FIG. 9 is a diagram showing a response change of an engine output torque change due to an engine load.

[Explanation of symbols]

 1 engine 2 automatic transmission 3 torque converter 6 control unit 8 throttle sensor 9 crank angle sensor 10 transmission output shaft 12 torque sensor

Claims (1)

[Claims] 1. An output shaft torque control device for an automatic transmission configured to transmit engine torque to a transmission mechanism via a torque converter, the operating state detecting means detecting an operating state of an engine, and an automatic state detecting means. Gear ratio detecting means for detecting a gear ratio before and after shifting of the transmission,
At least the target torque setting means for setting the target torque of the transmission output shaft during the shift based on the engine operating state detected at the start of the shift, the gear ratio before and after the shift, and the target shift time, and the torque of the transmission output shaft Torque detection means for detecting, ignition timing feedback control means for feedback-controlling the engine ignition timing during shifting so that the torque of the transmission output shaft detected by the torque detection means approaches the target torque, and the ignition timing feedback An output shaft torque control device for an automatic transmission, comprising: a control operation amount varying means for changing an operation amount of an ignition timing in the control means according to an engine operating state.