JPH01257729A - Control device for output of engine - Google Patents

Abstract

PURPOSE:To secure a stabilized traveling performance by controlling the engine output by its reduction with the reduction amt. set according to the driving power ratio in variable speeds at the shift-down time. CONSTITUTION:The shift-down detecting means C detecting the shift-down of variable speeds in the specified traveling state of a car is provided. The output of this shift-down detecting means C is input to the reduction amt. setting means F which sets the reduction amt. of the engine output by an engine output reducing means D according to the driving power ratio in variable speeds. At the shift-down speed changing time the engine output is controlled by reducing it according to the driving power ratio in variable speeds in the shift-down thereof and the variation in the driving power is reduced, hence a stabilized traveling performance can be secured even in case of cornering traveling on a low friction coefficient road.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an engine output control device that reduces engine output during downshifting.

(Prior Art) Conventionally, a technique for controlling engine output in order to reduce shift shock during gear shifting by an automatic transmission has been known, for example, as seen in Japanese Patent Laid-Open No. 55-69738. be.

(Problem to be Solved by the Invention) By the way, in a vehicle equipped with an automatic transmission, for example, when turning while keeping the accelerator in a fixed position, the vehicle speed decreases due to an increase in running resistance due to lateral panning resistance. The gear may be downshifted. In addition, a downshift may also occur during a turn on an uphill slope.

This downshift during a turn increases the driving force acting on the drive wheels after the gear change, which may cause torque shock and make cornering performance unstable. In particular, when the friction coefficient μ is extremely low, such as on a frozen road surface, if there is a fluctuation in the driving force during downshifting as described above, it will affect the driving performance even when not cornering, and the stability will deteriorate. This will result in a decline.

SUMMARY OF THE INVENTION In view of the above-mentioned circumstances, it is an object of the present invention to provide an engine output control device that reduces changes in driving force before and after a gear change during a downshift.

(Means for Solving the Problems) In order to achieve the above object, the output control device of the present invention has the following features:
A downshift detection means for detecting a downshift of a gear position in a specific driving state of a vehicle; an engine output reduction means for receiving an output of the downshift detection means and controlling an engine output to decrease during a downshift; and the engine output reduction means. and a reduction amount setting means for setting the amount of reduction in engine output according to the driving force ratio of the gear shift crotch.

FIG. 1 is a schematic configuration diagram for clearly showing the configuration of the present invention.

The driving force of the engine E of the vehicle is transmitted to the driving wheels via the automatic transmission A, and the gear position of the automatic transmission A is changed by a shift signal from the shift control means B. A downshift detection means C detects a downshift in the speed change control of the speed change control means B.

On the other hand, the engine E of the vehicle is provided with an output reducing means for reducing the engine output, for example, by adjusting the throttle valve opening. The amount of reduction in engine output due to this output reduction means is set by reduction amount setting means F.

The reduction amount setting means F includes the shift down detection means C.
A downshift signal is output from the engine, and the engine output is controlled to be lowered during downshifting. The amount of reduction in engine output is set in accordance with the driving force ratio between the gears during downshifting. Further, the above-mentioned output reduction control at the time of lift-down is performed in a specific driving state of the vehicle such as when cornering, and a driving state determining means G is provided to detect and determine the driving state of the vehicle, and the signal thereof is It is output to the reduction amount setting means F.

(Function) In the above-mentioned output control device, during a downshift, the engine output is controlled to decrease according to the drive force ratio between the gears during the downshift, thereby reducing changes in the drive force. This ensures stable driving performance even when cornering on roads with low friction coefficients.

(Example) The present invention will be described in detail below with reference to the drawings.

FIG. 2 is an overall configuration diagram of a specific example.

The output of an engine 2 mounted on a vehicle is transmitted to driving wheels 7 via an electronically controlled automatic transmission 3, a propeller shaft 4, a differential 5, and an axle 6. The automatic transmission 3 has a shift solenoid 8, and a controller 9 outputs a shift command signal to the shift solenoid 8, the hydraulic circuit is switched, and the shift mechanism is operated to switch between a plurality of gears. .

On the other hand, a throttle valve 12 is installed in the intake passage 11 of the engine 2 to adjust the amount of intake air, and this throttle valve 12 is connected to a throttle actuator 13 such as a DC motor.
The throttle valve 12 is driven to open and close by the throttle valve 12, and the intake air amount is adjusted by controlling the opening degree of the throttle valve 12 to thereby reduce the engine output. A control signal is output from the controller 9 to the throttle actuator 13 to adjust the throttle opening, and also perform intake air amount control at times other than when downshifting.

The controller 9 includes a vehicle speed sensor 2 that detects vehicle speed.
The vehicle speed signal from 1 and the amount of depression of the accelerator pedal 22 (
an accelerator opening signal from the accelerator sensor 23 that detects the accelerator opening (accelerator opening); a boost signal from the boost sensor 24 that detects intake negative pressure; and a throttle opening signal from the throttle sensor 25 that detects the opening of the throttle valve 12. The signal and a steering angle signal from a steering angle sensor 28 that detects the steering angle of the steering wheel 27 are respectively input.

Next, the processing of the controller 9 will be explained according to a flowchart.

FIG. 3 shows the main routine, in which the controller 9 performs a predetermined system initialization (step S) at the start of operation.
l), read detection signals from the various sensors, and input various information necessary for control from these (S2)
.

In step S3, normal throttle control is performed in which the throttle opening degree To is set and controlled based on the depression amount α of the accelerator pedal 22 according to predetermined control characteristics.

On the other hand, in step S4, the vehicle speed Vn and the accelerator depression amount α
A shift determination process is performed to determine the gear position from a shift map set correspondingly to the above, and when a shift is necessary, a shift signal is output to the solenoid 8 of the automatic transmission 3 to perform a shift operation.

Next, in step S5, a drive signal corresponding to the target throttle opening To is output to the throttle actuator 13, and in association with the shift control, the throttle opening is used as a parameter at the time of downshifting, and vehicle speed (engine rotation) - Using the torque map, the optimal throttle opening degree at the time of downshifting is determined and a throttle opening signal for reducing engine output is output to the throttle actuator 13. Then, the above routine is repeated for a predetermined period of time (for example, 30 m).
It is executed every 5ec).

Next, FIG. 4 shows a detailed subroutine of the throttle control in step S3 of the main routine. Enter the accelerator depression amount α in step SIO, and
The basic throttle opening degree map is searched using l, and the basic throttle opening degree Tb is determined from the accelerator depression amount α based on this map (S12). In this basic throttle opening map, the basic throttle opening Tb corresponding to the accelerator depression amount α is set corresponding to the gear position, and from this map, the basic throttle opening Tb corresponding to the detected accelerator depression amount α is set according to the gear position. is read, and the target throttle opening degree To is set in step 813.

FIG. 5 shows a detailed subroutine of the speed change control in step S4 of the main routine. First, enter the vehicle speed, accelerator opening, etc. (520), step S21.
In S22, a shift pattern in which a gear position is set in accordance with the accelerator opening degree α and the vehicle speed Vn is searched, and the gear position of the corresponding zone of the shift pattern is read based on the detected accelerator opening degree α and the actual vehicle speed Vn. Outputs the speed change signal (S
23).

FIG. 6 shows a detailed subroutine for output control in step S5 of the main routine. In step S30, it is determined whether or not a gear shift signal is output, and if a gear shift is to be performed, the process proceeds to step S31, where a turning map of steering angle θ and vehicle speed is searched, and the current driving is performed based on the detected value. It is determined whether the state is turning under this control (S32). The above turning map is set so that when the vehicle speed is low, it does not determine that the vehicle is turning even if the steering angle θ is large, and conversely, when the vehicle speed is high, it is determined that the vehicle is turning even if the steering angle θ is small. There is.

If the determination in step S32 is YES and the turning operation is in progress, the turning flag FO and the recovery flag F1 are set to 1.
533) and searches the shift=8-torque map during turning to determine the change in driving force FC associated with this downshift (S34). The shift down map uses the throttle opening as a parameter to calculate the vehicle speed (engine speed) at each gear position at each throttle opening.
The relationship between this and the driving force is registered in advance, and from the map of the corresponding throttle opening, the driving force FC2 acting on the drive wheels at the gear before downshifting at the current vehicle speed and the driving force at the gear after shifting are calculated. FC1 is calculated respectively. Then, in step S35, a correction coefficient k (throttle opening aperture coefficient) is calculated from the ratio of driving forces before and after downshifting, F C2 /F C1.

In the above-mentioned downshift during turning, the correction coefficient k is set to the target throttle opening T determined by the throttle control S3.
o is corrected to a smaller value (541), and a drive signal corresponding to this corrected throttle opening TO is output to the throttle actuator 13 (S42), thereby controlling the engine output to decrease.

Then, when the gear shift is completed during the turn, a No determination is made in step S30, and a No determination in step 838 causes the road cover flag F1 to be set, and step S3
9, the correction coefficient k is gradually brought closer to 1 (=
Recovery control is performed, and when the correction coefficient k becomes 1, the recovery flag F1 is reset to 0 (S 40
). This gradually increases the output and returns to normal.

Further, if the turning is completed during the gear shift, the step S32
If the judgment is No, the process proceeds to step 83B and the turning flag F is set.
Determine whether O is set. If the determination is YES while the vehicle is turning, the turning flag FO is reset in step S37, and the recovery flag F1 is set, so that when the gear shift is completed, the flag is returned to step S3 in the same manner as described above.
9 recovery control is performed.

As mentioned above, during downshifting, the engine output is controlled by reducing the throttle opening degree, but in the shift control, as shown in step S21, the gear position is determined based on the vehicle speed and the accelerator opening. Since the setting is based on the degree α, an upshift does not occur even if the throttle opening decreases in the above-mentioned downshift output control. In other words, if this shift pattern is set based on vehicle speed and throttle opening, when the throttle opening decreases during output reduction control, the gear may cross the shift line and shift to the gear before downshifting. In order to prevent such repeated gear changes, the gear shift pattern is set based on the vehicle speed and accelerator opening.

According to the embodiment described above, when the vehicle is turning on an uphill slope or the like, the gear determined by the shift pattern changes to a lower speed side in response to a decrease in vehicle speed or an increase in the degree of accelerator opening. When downshifting, the drive force ratio between the front and rear gears is determined, a correction coefficient is set, and the throttle opening is reduced in accordance with this drive force ratio to control the engine output. The change in driving force associated with downshifting is minimized, improving driving stability.

In addition, when ending engine output reduction control due to completion of a downshift, etc., the throttle opening is gradually increased using recovery control to avoid a sudden increase in driving force and to obtain more stable driving performance. I have to.

In the first embodiment, the output reduction control is not performed during the 1-down shift when the vehicle is not turning, but it may be performed when the vehicle is not turning or in other driving states.

(Effects of the Invention) According to the present invention as described above, downshifting in a specific driving state of the vehicle is detected, and at the time of downshifting, the engine output is controlled to be reduced by a reduction amount set according to the driving force ratio between the gearshift crotches. By doing so, the change in driving force during downshifting can be reduced to a minimum, and stable driving performance can be ensured even when cornering on a road surface with a low friction coefficient.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of the entire tank to clarify the configuration of the present invention, Fig. 2 is a control system diagram in one embodiment, Fig. 3 is a main flow chart showing the overall control operation, and Figs. FIG. 6 is a flowchart of the main parts of each control section. A, 3: Automatic transmission, C: Downshift detection means, D: Output reduction means, E, 2
... Engine, F ... Decrease amount setting means, ]
... Vehicle, 7 ... Drive wheel, 9 ... Controller, 12 ... Throttle valve. Figure 3 Figure 4

Claims (1)

[Claims] (1) A downshift detection means for detecting a downshift of a gear in a specific driving state of the vehicle; an engine output reduction means for receiving the output of the downshift detection means and controlling the engine output to decrease during a downshift; and the engine 1. An engine output control device comprising a reduction amount setting means for setting an amount of reduction in engine output by the output reduction means in accordance with a driving force ratio between gear stages.