JPS63105247A - Engine control device in vehicle with automatic transmission - Google Patents

Abstract

PURPOSE:To enable a speed change shock to be reduced when an automatic transmission is shifted down, by performing a correction control so as to decrease an engine output in a period that the automatic transmission advances the switching action of its speed change gear mechanism increasing output shaft torque. CONSTITUTION:An automatic transmission 1 is controlled by a control unit 10 which stores a speed change pattern in memory, and a speed change mechanism in the automatic transmission 1, when it is shifted down, performs the switching action with a certain time delay in accordance with a shift down signal from the control unit 10. Here within a period torque rises relatively rapidly during the switching action, an engine output decreases by the control unit 10 correcting a fuel injection amount of an engine 2 in a decreasing direction. In this way, the peak torque, generated when the torque is transferred to a value after a shift down via a torque rising process, can be suppressed, and a speed change shock caused by the above can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an engine control 11 device for a vehicle with an automatic transmission, and particularly relates to control during downshifting.

(Prior Art) In general, automatic transmissions automatically shift gears based on a preset shift pattern depending on the driving condition of the vehicle. A preset shift pattern is stored in the control section, and the shift is controlled according to this shift pattern.

In addition, in vehicles equipped with such automatic transmissions,
2. Description of the Related Art A fuel supply device as disclosed in, for example, Japanese Patent Application Laid-Open No. 56-96129 is known as a device for controlling an engine in connection with an automatic transmission. This device is
For example, when an automatic transmission is shifted up from first gear to second gear, or from second gear to third gear, the output shaft torque of the automatic transmission temporarily increases after a shift-up signal is received. Considering that there is a certain timing, in order to suppress this torque increase, the fuel supply amount is reduced during the above-mentioned upshift to lower the engine output.

By the way, in the above-mentioned conventional technology, only the torque fluctuation during upshifting is focused, but there is also shift shock during downshifting, and one of the causes of shift shock during downshifting is the switching of the transmission gear mechanism. There is a peak torque that occurs near the end of the operation. In other words, in automatic transmissions, downshifts are automatically performed in response to changes in throttle opening during acceleration, decreases in vehicle speed during deceleration, etc. During such downshifts, after receiving a shift down signal, The transmission gear mechanism actually starts switching operation with a certain degree of activation, and the output shaft torque of the automatic transmission fluctuates in accordance with this switching operation. In this case, ``The torque value after downshifting is higher than the torque value before downshifting, so as the above switching operation progresses, the output shaft torque increases relatively rapidly, but near the end of the above switching operation. In this case, before the output shaft torque converges to the torque value after downshifting, there is a tendency for the output shaft torque to increase excessively and produce a peak torque, and when this peak torque is high, it gives a feeling of shock. To solve this problem, it is possible to reduce the engine output in synchronization with the gear shift signal, but doing so will hinder the acceleration performance at the beginning of the downshift, for example, when downshifting during acceleration, making it insufficiently effective. It was not a suitable countermeasure.

(Object of the Invention) In view of the above circumstances, the present invention provides an engine control m+ device for a vehicle with an automatic transmission that can reduce shift shock caused by the peak torque as described above during downshifting of the automatic transmission. It is something to do.

(Structure of the Invention) As shown in the configuration explanatory diagram of FIG. 1, the present invention provides a vehicle equipped with an automatic transmission 1 that changes gears based on a gear shift pattern set in advance according to the driving state of the vehicle. an engine output adjusting means 3 for adjusting the output of the engine 2; a detecting means 4 for detecting a state in which a gear change operation is in progress after the gear mechanism has actually started to change during downshifting of the automatic transmission 1; Engine output control means 5 is provided for outputting a control signal to the engine output adjustment means 3 to reduce the engine output by one level while the switching operation is in progress in accordance with the detection.

In other words, the automatic transmission 1 is controlled by the control unit 6 that stores a shift pattern, and when downshifting, the transmission gear mechanism in the automatic transmission 1 is activated with a certain amount of delay in response to a downshift signal from the control unit 6. However, in this case, during the switching operation, the engine output is controlled in a downward direction during the period when the torque increases relatively rapidly, so that the peak torque mentioned above is suppressed. ing.

(Example) Fig. 2 shows the overall structure of an automatic transmission 811, an engine 2, and a control system for these. It is a control unit (ECU). The automatic transmission 1 is composed of a torque converter, a gear change mechanism, and a hydraulic circuit that drives the mechanism, and is incorporated into the hydraulic circuit. ! A gear shift is performed by controlling J number of solenoid valves 11 by a control unit 10. The speed change gear mechanism of the automatic transmission 1 is generally known, so detailed explanation and illustration are omitted, but it includes various gear elements combined with a predetermined planetary gear structure, a brake that controls the movement of these gear elements, It is composed of various friction elements such as clutches and one-way clutches, and the gear ratio changes according to the operation of the friction elements. The automatic transmission 1 includes a vehicle speed sensor 12 that detects vehicle speed from the rotation of its output shaft, and an inhibitor switch 13 that detects neutral and parking states.
A turbine rotation speed sensor 14 is attached to detect the turbine rotation speed of the torque converter, and signals from these sensors are input to the control unit 10.

On the other hand, the engine 2 is equipped with an intake passage 15, an exhaust passage 16, a fuel system consisting of a fuel injection valve 17, a fuel pump 18, etc., and an ignition system consisting of a spark plug 19, a distributor 20, an igniter 21, etc. A throttle valve 22 is arranged in the intake passage 15. 23 is an air flow meter that detects intake air, 24 is a crank angle sensor attached to the distributor 20, 25 is a throttle opening sensor that detects the opening of the throttle valve 22, and 26 is an 02 sensor provided in the exhaust passage 16. , and signals from these are also input to the control unit 10.

Furthermore, the control unit 10 includes a signal 1 (1, 2, D range signal) 27 that specifies the range of the automatic transmission 1;
Signals 28 and the like from the ignition switch are input. In addition, various signals necessary for controlling the automatic transmission 1 and the engine 2 are input to the control unit 1.
All you have to do is input it to 0.

The control unit 10 controls the automatic transmission 1 in advance.
A shift pattern in which the shift position of If! is set according to the vehicle speed and throttle opening is stored, and automatic shift If! is performed based on this shift pattern. The signal that controls the solenoid valve 1
At the same time, signals for controlling the fuel system, ignition system, etc. of the engine 2 are outputted to the fuel injection valve 17, fuel pump 18, igniter 21, etc. Particularly during downshifting, the engine output is controlled by outputting a control signal for correcting the fuel injection amount to the fuel injection valve 17 as described later. Therefore, the control unit 10 includes the control section 6, the detection means 4, and the engine output control means 5 shown in the configuration explanatory diagram of FIG. has been done.

Note that the control of the automatic transmission 1 and the control of the engine 2 may be performed by separate control units, but in this case, communication may be performed between each control unit.

An outline of the control operation by the control unit 10 will be explained with reference to the time chart in FIG. 3. In response to changes in throttle opening due to acceleration, changes in vehicle speed due to deceleration, etc.,
A total of 11 values of the gears based on the gear shift pattern change to the lower gear side, and at that point t.

When a shift down signal is output to the solenoid valve 11, the transmission gear mechanism switches and operates with a certain delay in response, and accordingly, the output shaft torque of the automatic transmission fluctuates as shown by line A. At the same time, the turbine rotation speed changes as iB. In other words, the above output shaft torque temporarily decreases due to the resistance of the rotating body when the transmission gear mechanism actually starts to change, and then rapidly rises as the switching operation progresses, but the timing at which the switching operation ends In the vicinity, there is a tendency for the torque to temporarily increase excessively and produce a peak torque (line A1) before converging to the torque value after the downshift. Further, the turbine rotational speed increases according to a change in gear ratio from the time when the speed change gear mechanism starts switching, and becomes stable once the switching operation is completed. The more rapid the change in the turbine rotational speed, the more rapid the torque fluctuation, and therefore the larger the peak torque.

Therefore, based on the detection of changes in the turbine rotation speed, for example, by detecting when the turbine rotation speed reaches a reference rotation speed Nl that is set to a certain degree lower than the expected convergence rotation speed NC, the speed change gear n mechanism is actually Detects the time t1 in the process of increasing the torque when switching starts, and at this time) 11
Starting from 4t+, the engine output is reduced by correcting the fuel injection port in the decreasing direction. In this embodiment, the fuel correction mVh in this case is set in accordance with the elevation degree ΔN of the turbine rotational speed, and as shown in FIG. ing. In addition, it is desirable that the correction amount h be changed depending on the gear stage, oil pressure, throttle opening, etc. at the time of downshifting, which are related to the 1 to 1 torque fluctuation. Further, the end timing of the fuel correction is assumed to be the time t2 when the turbine rotation speed reaches the expected convergence rotation speed NC. Alternatively, when downshifting due to acceleration, the turbine rotation speed will rise above the expected convergence rotation speed NC (line B-), so in consideration of this situation, correction may be finished when the turbine rotation speed has stabilized after increasing. good.

This control will be explained using the flowchart in Fig. 5. This flowchart will be explained when the ignition switch is
The process starts with , initialization is performed in step S1, and thereafter, the process from step 82 onwards is repeated.

In step S2, information from various sensors and switches is read, and in step S3, a basic injection amount vb of fuel is calculated according to the intake air amount, engine speed, etc. Subsequently, in step S4, a gear position is calculated based on the shift pattern according to the vehicle speed and the throttle opening, and a corresponding control signal is output to the solenoid valve 11 (step 85). Next, in step S8, it is checked based on the detection of the turbine rotational speed, etc., whether or not the speed change operation is in progress from the start to the end of the speed change operation in response to the downshift signal. If this determination result is No, step S
In Step 7, the basic injection amount vb is set as the final injection port V, and in Step S8, a control signal corresponding to the final injection amount ■ is output to the fuel injection valve (injector) 17, and then the process returns to Step $2.

When the determination result in step S6 is YES, it is checked in step S9 whether or not the correction amount for fuel injection (1) lffi has been determined. If the correction amount has not yet been determined, as a process for determining the correction timing and correction amount, an expected convergence rotation speed NO is determined based on the value Na before the increase in the turbine rotation speed and the gear ratio in step S°C, and step In S11, the expected convergence rotation speed NC is multiplied by a constant coefficient K to obtain the reference rotation speed Nb.
(see Fig. 3), and in step S12 calculates the turbine rotational speed increase ΔN, and in step St3 sets the correction mVh according to the increase ΔN as described above, and then proceeds to step S14. Move. Further, if the correction amount has been determined (the determination result in step S9 is YES), the process proceeds to step S14 without passing through step S+o-813.

In step 814, the turbine rotation speed is set to the reference rotation speed N.
It is checked whether or not the rotation speed Nb has been reached, and the process moves to step S7 and no correction is performed until the reference rotation speed Nb is reached. After reaching the reference rotation speed Nb, it is determined in step S15 whether the expected convergence rotation speed NG has been reached. Then, until the expected convergence rotation speed NO is reached, the process moves to step S1a, and the value obtained by subtracting the above correction amount h from the basic injection MVb is set as the final injection amount V, and then the process returns to step S2 via step S8. . After reaching the expected convergence rotation speed NC,
The correction ends by moving to step S7.

With the above-described control, during downshifting, the peak torque that occurs near the end of the switching operation of the transmission gear mechanism is reduced. i.e. before)! ! According to the switching operation of the transmission gear mechanism during downshifting, the output shaft torque of the automatic transmission rapidly reaches its upper limit from the point when the operation has progressed to a certain extent, but the period during which this torque increase occurs To, fuel patrol! 8 The suspension is corrected in the decreasing direction and the engine output is reduced, thereby suppressing a sudden increase in torque at the end of the switching operation. Therefore, as shown by line 2 in Figure 3, the output shaft torque smoothly transitions to the torque value after downshifting, and compared to the conventional (IilAl), the peak torque is smaller, reducing the shock feeling. It happens.

In the above embodiment, the correction control of the engine output at the time of downshifting is performed by suspending the fuel injection, but instead of this, the ignition timing may be controlled. In this case, the ignition timing is adjusted at the predetermined timing described above. should be corrected to the retard side. In addition, it is also possible to use a gas flow rate or the like.

(Effects of the Invention) As described above, the present invention reduces the engine output during the period 1111 when the switching operation of the transmission gear mechanism progresses and the output shaft torque increases during downshifting of the automatic transmission. Since the transmission is corrected and controlled, it is possible to suppress the peak torque that occurs when the torque increases and shifts to the torque value after downshifting, and the shift shock caused by this peak torque can be reduced. It is.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of the configuration of the present invention, Fig. 2 is a schematic diagram of the overall structure showing an embodiment of the present invention, and Fig. 3 is a control diagram for downshifting.
FIG. 4 is a time chart showing an outline of the II operation, FIG. 4 is a diagram showing the relationship between the degree of increase in turbine rotation speed during downshifting and the correction amount of fuel injection m, and FIG. 5 is a flow chart showing a specific example of control. . DESCRIPTION OF SYMBOLS 1... Automatic transmission, 2... Engine, 3... Engine output adjustment means, 4... Detection means, 5... Engine output control means, 10... Control unit. Patent applicant Mazda Co., Ltd. Agent
People Patent Attorney Etsushi Kotani
Patent Attorney Chief 1) Masamukai Patent Attorney
Yasuo Neya No. 1 Illustration/6 Anger

Claims (1)

[Claims] 1. In a vehicle equipped with an automatic transmission that changes gears based on a preset shift pattern depending on the driving condition of the vehicle, there is an engine output adjustment means that adjusts the output of the engine, and an engine output adjustment means that actually changes gears when downshifting the automatic transmission. a detection means for detecting a state in which the switching operation is in progress after the gear mechanism has started switching, and in response to this detection, outputting a control signal to the engine output adjustment means to reduce the engine output while the switching operation is in progress. 1. An engine control device for a vehicle with an automatic transmission, characterized in that an engine output control means is provided.