JPS63105248A - 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 synchronously with a rise of engine or turbine speed. CONSTITUTION:An automatic transmission 1 is controlled by a control unit 10 which stores a speed change pattern in memory, and a speed change gear mechanism in the automatic transmission 1, in the time of its shift down, performs the switching action with a certain time delay in accordance with a shift down signal from the control unit 10. Here a change of torque is generated while engine and turbine speeds increase in accordance with the above switching action. In this time, an engine output decreases by correcting a fuel injection quantity of an engine 2 in a decreasing direction by the amount in accordance with a degree of the increase of the speeds. In this way, the peak torque, generated when the torque is transferred to a value after the shift down via a torque increasing process, can be suppressed, and a speed change shock due to the above can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an engine control device for a vehicle with an automatic transmission, and particularly 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
When an automatic transmission is shifted up, for example from 1st gear to 2nd gear, or from 2nd gear to 3rd gear, the output shaft torque of the automatic transmission temporarily increases after a shift-up signal is received. Taking note of this fact, in order to suppress this torque increase, the engine output is reduced by reducing the fuel supply (2) at the time of the above-mentioned upshift.

By the way, in the above-mentioned conventional technology, only the torque fluctuation during upshifting is focused, but there is also a shift shock during downshifting, and one of the causes of the 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 delay in operation vJ, 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 switching operation progresses, the output shaft torque increases relatively rapidly, but near the end of the switching operation, the output shaft torque increases. 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 if this peak torque is high, it gives a feeling of shock. When downshifting, the engine speed and the turbine speed of the automatic transmission increase due to the change in gear ratio, but the greater the increase in speed, the more rapid the torque change, and the higher the peak torque. (See Figure 3). Conventionally, no sufficiently effective countermeasures have been taken against such problems.

(Object of the Invention) In view of the above-mentioned circumstances, the present invention is capable of reducing the shift shock caused by the above-mentioned peak torque when downshifting an automatic transmission, and in particular reduces the output to an extent commensurate with the magnitude of the peak torque. An engine control device for a vehicle with an automatic transmission capable of adjusting shaft torque is provided.

(Structure of the Invention) According to the present invention, as shown in the configuration explanatory diagram of FIG. an engine output adjusting means 3 for adjusting the output of the engine 2; a rotational speed increase detection means 4 for detecting the degree of increase in the engine rotational speed or the turbine rotational speed of the automatic transmission when downshifting the automatic transmission ta1; An engine output 11, 11111 that outputs a control signal to the engine output adjusting means 3, which lowers the engine output in synchronization with the increase in the rotation speed, and increases the engine output reduction I as the rotation speed increases. Means 5 is provided.

In other words, the automatic gear shift B11 is controlled by the control section 6 that stores a shift pattern, and during downshifting, the automatic transmission B11 is controlled by the shift gear mechanism in the automatic transmission 1 in response to a downshift signal from the control section 6. As torque fluctuation occurs, the engine speed and turbine speed increase, but at this time, the engine output is reduced by an amount corresponding to the degree of increase in the speed, so that the peak torque can be moderately suppressed. It has become.

(Example) Fig. 2 shows the overall structure of the automatic transmission 1, the engine 2, and the control system for these.
10 is a control unit (ECtJ) that comprehensively controls the automatic transmission 1 and the engine 2. The automatic transmission Ia1 is composed of a torque converter, a transmission gear mechanism, and a hydraulic circuit that drives the same, and a plurality of solenoid valves 11 incorporated in the hydraulic circuit are controlled by the control unit 10 to perform transmission. It has become. The speed change gear mechanism of the automatic transmission 1 is as follows:
Detailed explanations and illustrations will be omitted as they are generally known, but various gear elements combined in a predetermined planetary gear structure, and various *m elements such as brakes, clutches, and one-way clutches that control their movements, will be omitted. The gear ratio changes according to the operation of the friction element. The automatic transmission 1 includes a vehicle speed sensor 12 that detects the vehicle speed from the rotation of its output shaft, an inhibitor switch 13 that detects neutral and parking states, and a turbine rotation speed sensor 14 that detects the turbine rotation speed of the torque converter. signals from these 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. 623 is an air meter that detects the intake air m, 24 is a crank angle sensor attached to the distributor 20, and 25 is an opening of the throttle valve 22. A throttle opening sensor 26 is installed in the exhaust passage 16 to detect the iQ
02 sensor, and signals from these are also input to the control unit 1o.

Furthermore, the control unit 1o includes an automatic transmission tj1.
Signal specifying range 1 (1, 2, D range signal) 2
7. A signal 28 etc. from the ignition switch is input. In addition to this, automatic transmission f! Various signals necessary for controlling the engine 11 and controlling the engine 2 may be inputted to the control unit 10.

The control unit 10 controls the automatic transmission 1 in advance.
A shift pattern in which the shift position of the engine is set according to the vehicle speed and throttle opening degree is stored, and a signal for controlling the automatic transmission 1 is outputted to the solenoid pulp 11 based on this shift pattern, while the fuel system of the engine 2, Signals for controlling the ignition system and the like are output to the fuel injection valve 17, fuel pump 18, igniter 21, and the like. Particularly during downshifting, the engine output is decreased by outputting to the fuel injection valve 17 a control signal that corrects the fuel injection port according to the turbine rotational speed as described later. Therefore, the control unit 10 includes the control section 6, rotational speed increase detection means 4, and engine output control means 5 shown in the configuration explanatory diagram of FIG. Means 3 is configured.

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.,
The calculated value of the gear position based on the gear shift pattern changes to the lower gear side, and at that time 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 shown by line B. In other words, the output shaft torque temporarily decreases due to the resistance of the rotating body when the transmission gear mechanism actually starts to switch, and then rapidly increases as the switching operation progresses. In this case, the torque tends to temporarily increase excessively and produce a peak torque (IAl) 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, the fuel injection m is corrected in synchronization with the increase in the turbine rotation speed, for example, based on the detection of a change in the turbine rotation speed.
This is detected at time t1 when the turbine rotation speed reaches a reference rotation speed Nb that is set to a certain degree lower than the expected convergence rotation speed NC, and from this time t1, the engine output is reduced by correcting the fuel injection layer in the decreasing direction. I'm letting you do it. The fuel correction ff1Vh in this case is set according to the degree of rise ΔN in the turbine rotational speed, and as shown in FIG. 4, the larger the degree of rise ΔN becomes, the larger the fuel correction Φvh becomes. In addition, it is desirable that the correction value vh be changed depending on the gear position, oil pressure, throttle opening, etc. at the time of downshifting, which are related to torque fluctuations. 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 NO.

Alternatively, when downshifting due to acceleration, the turbine rotation speed increases from the expected convergence rotation speed Nc (line B'), so
In consideration of such a case, the correction may be terminated when the turbine rotational speed becomes stable after increasing.

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 total of n fuel injection phrases vb are performed according to the intake air amount, engine speed, etc.

Subsequently, in step S4, the gear position is calculated based on the shift pattern according to the vehicle speed and the throttle angle of 1 m, and a corresponding control signal is output to the solenoid valve 11 (step S5). Next, in step S8, it is determined 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. When this determination result is No, in step S7, the basic injection amount ■b is set as the final injection ff1V,
After outputting a control signal corresponding to the final injection amount ■ to the fuel injection valve (injector) 17 in step S8, step S8
Return to 2.

When the determination result in step S8 is YES, fuel injection is performed in step S9! Check whether the correction amount for the lFl amount has been determined. If the correction m has not yet been determined, as a process for determining the correction timing and the correction amount, an expected convergence rotation speed NO is determined based on the value Na of the turbine rotation speed before the rise and the gear ratio in step S10, and step S11 In step Sr2, the predicted convergence rotation speed NC is multiplied by a constant coefficient K to set the reference rotation speed Nb (see Fig. 3), and in step Sr2, the turbine rotation speed increase degree ΔN is calculated, and in step S13, the above increase degree is calculated. The correction amount vh is adjusted according to ΔN as shown in FIG.
After setting, the process moves to step S14. Further, if the correction m has been determined (the determination result in step S9 is YES), the process proceeds to step S1 without passing through steps 510-813.
Move on to 4.

In step S%, the turbine rotation speed is the reference rotation speed Nb.
It is checked whether the rotational speed Nb has been reached, and the process moves to step S7, so that no correction is performed until the reference rotational speed Nb is reached. After reaching the reference rotation speed Nb, it is determined in step S15 whether the expected convergence rotation speed NC has been reached. Then, until the expected convergence rotation speed NG is reached, the process moves to step SII, where the value obtained by subtracting the correction ff1Vh from the basic injection amount ■b is set as the final injection amount ■, 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. In other words, as mentioned above, shift down
In response to the switching operation of the transmission gear mechanism at the time of switching, the output shaft torque of the automatic transmission rapidly increases after the operation has progressed to a certain extent. The peak torque increases as the turbine rotational speed increases. On the other hand, in the above control, when the turbine rotation speed increases, the fuel injection amount is reduced by the positive amount according to the degree of increase, so that the sudden increase in torque corresponding to the degree of increase in the turbine rotation speed is moderately suppressed. . Therefore, as shown by llA2 in Fig. 3, the output shaft torque smoothly transitions to the torque value after downshifting, the peak torque becomes smaller than the conventional one (line A1), and the feeling of shock is reduced. Become.

In the above embodiment, the engine output is corrected based on the detection of the turbine rotation speed when downshifting. The engine speed may be detected instead of the rotation speed. Further, the correction control of the engine output during downshifting may be performed using ignition timing instead of fuel injection M, and in this case, the ignition timing may be adjusted at the predetermined timing described above.

(Effects of the Invention) As described above, the present invention corrects and controls the engine output in a downward direction in synchronization with an increase in the engine speed or the turbine speed of the automatic transmission when downshifting the automatic transmission. It is possible to suppress the peak torque that occurs when the output shaft torque of the automatic transmission shifts to the torque value after downshifting through a torque increase process. In particular, considering that the degree of increase in the rotation speed is related to the magnitude of the peak torque, the degree of decrease in engine output is increased as the degree of increase in the rotation speed increases. , it is possible to appropriately suppress the peak torque and effectively reduce shift shock.

[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 invention, Fig. 3 is a time chart showing an outline of the control operation during downshifting, and Fig. 4 is a downshifting diagram. FIG. 5 is a flowchart showing a specific example of control. DESCRIPTION OF SYMBOLS 1... Automatic transmission, 2... Engine, 3... Engine output subsurface means, 4... Rotation speed increase 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 Itaya No. 1 Figure 9, Figure 3 ζ

Claims (1)

[Claims] 1. In a vehicle equipped with an automatic transmission that changes gears based on a shift pattern set in advance according to the driving condition of the vehicle, an engine output adjustment means that adjusts the output of the engine and an engine rotation speed when downshifting the automatic transmission. Alternatively, a rotation speed increase detection means detects the increase in the turbine rotation speed of the automatic transmission, and the engine output is reduced in synchronization with the increase in the rotation speed during the downshift, and the rotation speed increase is large. 1. An engine control device for a vehicle with an automatic transmission, comprising: an engine output control means for outputting a control signal to the engine output adjustment means to increase the amount of decrease in engine output.