JPH05180321A - Output shaft torque control device for automatic transmission - Google Patents

Abstract

PURPOSE:To improve converging performance of feedback control for bringing transmission output shaft torque close to target torque at gear change. CONSTITUTION:When an elapsed time T from when start of transmission operation (inertia phase) is detected is less than a predetermined time t1, feedback control for an ignition timing is prohibited (S5 to S6) so as to prevent generation of undershoot accompanying delayed control. And during when the predetermined time t1 has elapsed to reach a target transmission time t2, feedback control for the ignition timing is executed to bring transmission output shaft torque close to target torque.

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, in the conventional torque control during the shift, the feedback control is performed immediately after the shift shifts from the so-called torque phase to the inertia phase (immediately after the change of the gear ratio occurs). When the torque jumps out in the initial phase of the inertia phase, a large ignition timing correction amount is generated, which causes a large undershoot of the torque, resulting in a problem that the shift shock cannot be controlled well.

That is, as shown in FIG. 10, the start of torque control during shifting is determined by detecting the torque phase, the target torque is set, and then the actual ignition timing feedback control is performed after shifting to the inertia phase. However, since the torque reduction effect by the correction of the ignition timing occurs with a delay, it is not possible to effectively reduce the jumping out of the torque that occurs in the initial phase of the inertia phase. Therefore, as shown in FIG. 9, a correction value for greatly retarding the ignition timing is set to correct the torque jump (point A in FIG. 9) (point B in FIG. 9). Since the effect of lowering the torque also occurs with a delay, a large torque undershoot is generated (point C in FIG. 9), and the subsequent torque greatly fluctuates due to the occurrence of such undershoot, and the target torque is reduced. The convergence of was worse.

The present invention has been made in view of the above circumstances. In feedback control of ignition timing for smoothly changing the output shaft torque of a transmission during gear shifting, the present invention is not affected by the torque jump at the start of the inertia phase. Instead, the object is to improve the convergence to the target torque during the shift.

[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 during gear 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 inertia phase detection means detects the inertia phase during gear shifting, and the feedback control prohibition means uses the ignition timing feedback control means from the initial time of inertia phase detection by the inertia phase detection means until a predetermined time elapses. Prohibit feedback control of ignition timing.

[0011]

With this configuration, the ignition timing is feedback-controlled in order to bring the transmission output shaft torque during gear shifting closer to the target torque, but such feedback control of the ignition timing is prohibited during a predetermined time period at the beginning of the inertia phase. Feedback control is started after the predetermined time has elapsed.

That is, if feedback control of the ignition timing is executed immediately from the beginning of the transition from the torque phase to the inertia phase, a large undershoot occurs immediately after the transition due to the control delay, and this undershoot causes subsequent convergence to the target torque. Therefore, the feedback control is prohibited during the predetermined time in the initial phase of the inertia phase, thereby avoiding the occurrence of a large undershoot and ensuring the convergence to the target torque thereafter.

[0013]

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, the inertia phase detecting means, and the feedback control inhibiting means are as shown in the flowcharts of FIGS. Are prepared for.

First, step 1 (denoted as S1 in the figure,
The same applies hereinafter), the value of the control start flag F is determined. The flag F is set to 1 when the start of a gear shift operation (inertia phase) (start of change in the gear ratio) is detected, and is reset to 0 when the gear shift time ends, as described later. When the flag F is 0, the routine proceeds to step 2, where it is judged whether or not the shift operation (inertia phase) is started. For example, since the output shaft torque of the transmission suddenly decreases (torque phase) when the clutch is released at the start of gear shifting, and the torque sharply increases after the clutch engagement starts (inertia phase), the shift operation is detected by detecting the torque change. The start of the inertia phase (the start of the change in the gear ratio) can be determined.

If it is determined in step 2 that the gear shifting operation (inertia phase) 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. The initial value of the basic control amount RETIN and the target shift time t2 in the ignition timing control which will be described later are set. As shown in FIG. 5, these values are gear stages obtained from the gear ratio Gb before gear shift and the gear ratio Ga after gear shift according to the type of gear shift (1st gear → 2nd gear, 2nd gear → 3rd gear, etc.). Using the ratio GR (= Ga / Gb) and the throttle valve opening TVO as parameters, the initial value of the basic control amount RETIN and the target shift time t are searched and set from a map that has been stored.

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, the value of the timer T that measures the elapsed time after the start of the gear shifting operation (from the transition from the torque phase to the inertia phase) is compared with the predetermined time t1 that determines the feedback control inhibition period, and the predetermined time If it is within t1, the process proceeds to step 6, the initial value of the basic control amount RETIN (open loop control value) is output, and the control is ended.

On the other hand, if the predetermined time t1 or more has elapsed since the shift operation was started (after the shift to the inertia phase), the routine proceeds to step 7, where the target shift time t2 set in step 4 is set. It is determined whether or not Then, when the value of the timer T has reached the target shift time t2, it is determined that the shift is completed, and step 9
Then, after the flag F is reset to 0, this control is finished. On the other hand, when the value of the timer T has not reached the target shift time t2, the shift is in progress, so the routine proceeds to step 8,
Basic control amount RETIN initialized in step 4
To gradually increase with the lapse of time T after the start of the gear shifting operation,
Update with the value obtained by adding ΔRETIN (> 0).

After step 8, the process proceeds to step 10 and subsequent steps to execute the ignition timing feedback control for bringing the transmission output shaft torque during shifting to the target torque.
That is, basically, feedback control to the target torque is performed during the inertia phase,
The feedback control is prohibited at a predetermined time t1 immediately after the transition from the torque phase to the inertia phase. By prohibiting such control, an excessive ignition timing correction amount is set based on a large torque jump that occurs immediately after shifting to the inertia phase, and when the excessive ignition timing correction amount is effective, a large torque under It is possible to avoid the occurrence of a chute, and to prevent a large torque fluctuation thereafter from occurring due to the occurrence of the undershoot. Therefore, it is possible to improve the convergence to the target torque during the shift.

The predetermined time t1 may be variably set according to parameters such as the output shaft torque before shifting, engine load and engine speed, or may be a constant value. In step 10, the target torque TRQREF of the transmission output shaft during shifting is set.

Specifically, based on the gear ratio before and after the gear shift and the engine speed N at the start of the gear shift, the engine speed Naf after the gear shift when the vehicle speed VSP is kept constant is determined. 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 that the torque TRQst corresponding to the engine speed N immediately before the shift and the 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 that it changes at a constant rate from the pre-shifting torque TRQst to the post-shifting torque TRQend at the target shifting time t2. 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 ratios before and after gear shifting are set according to 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 11, 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 gear shift set in step 10.
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 12, a value CUTCYL indicating the number of cylinders for which the fuel supply is stopped in the fuel supply cylinder number control which is carried out in parallel with the ignition timing control at the time of shifting according to the present invention.
Is reset to 0. In step 13, 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.

If it is judged at step 13 that KMR = 0, it means that it is a region other than the high output region. In this case, the control for the number of fuel supply cylinders is not performed and the routine jumps to step 17 to control the ignition timing. However, in the high output region where KMR ≠ 0, the process proceeds to step 14. In step 14,
The deviation TQRERR calculated in step 11 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 fuel supply is stopped, and the routine proceeds to step 15, where the value CUTCYL indicating the number of cylinders for which fuel supply is stopped is set. After counting up, go to step 16. In step 16,
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 a value subtracted from RERR, the process returns to step 14 and the same determination is performed again. In this way, when TQRRRR ≦ TRQDWN, the routine proceeds to step 17, 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 17, 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 18, the ignition timing retard control amount RETAT is calculated using the control constant set in step 17 according to the following equation.

RETAT = K _p · TRQERR + K _i ∫TRQERR + K _D · d / dt (TRQERR) + RETIN That is, the basic control amount RE as a 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 8 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 this embodiment, as described above, in step 17, 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, as shown in FIG. 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, the target torque can be approached with a constant response characteristic, and the followability to the target torque is deteriorated, 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 19, 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 20, 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 18,
The data under the same condition of the map storing the initial value of the basic control amount RETIN is rewritten. Meanwhile, step
If it is determined in 19 that the second time or later, step 20 is jumped to step 21.

As described above, by learning and modifying the initial value of the basic control amount RETIN to a value according to the result of the first 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 21, 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 22, Step
The ignition timing is retarded by the retard control amount RETAT set in 18. 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.

[0042]

As described above, in the feedback control of the ignition timing for obtaining the target torque at the time of shifting, the feedback control is prohibited at a predetermined time at the beginning of the inertia phase. There is an effect that the output shaft torque of the transmission can be controlled satisfactorily without being affected by the jumping out of the torque, and the effect of reducing the shift shock can be satisfactorily exhibited.

[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 feedback control constant map of the embodiment.

FIG. 9 is a time chart showing the relationship between torque fluctuation during gear shift and ignition timing correction amount (feedback control amount).

FIG. 10 is a time chart for explaining the occurrence of a control delay during gear shifting.

[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 detecting means for detecting, ignition timing feedback control means for feedback-controlling engine ignition timing during shift so that the torque of the transmission output shaft detected by the torque detecting means approaches the target torque, and inertia during shift Inertia phase detecting means for detecting a phase, and feedback control inhibiting means for inhibiting feedback control of ignition timing by the ignition timing feedback control means from a first time of inertia phase detection by the inertia phase detecting means until a predetermined time elapses. And an automatic changer characterized by including Output shaft torque control device for speed machines.