JPH0680050A - Vehicle control device - Google Patents

Abstract

PURPOSE:To securely prevent the occurrence of engine stalling even in the case of panic braking during traveling by carrying out throttle control after the lockup of an automatic transmission has been released on the basis of the judgment or the like of the brake input at the time of deceleration, so that the output of an engine can be reduced. CONSTITUTION:When braking operation is not carried out with the operation of an accelerator in a normal traveling condition, the releasing condition of a lockup clutch 121 is brought into a connected condition simultaneously with the completion of a deceleration control region, while when brake-tread-in operation is carried out inside the deceleration control region, the rotating speed of an internal combustion engine 11 suddenly drops with the decrease in the vehicle speed, so that engine stalling is caused. However, when braking operation is carried out in the deceleration control region, the lockup clutch 121 of an automatic transmission 12 is released, thereby slip is caused in the transmission part, and the occurrence of engine stalling can be eventually avoided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a countermeasure against engine stall during deceleration caused by engine braking, particularly in a vehicle using an automatic transmission, and enables stable deceleration control even during sudden panic braking. The present invention relates to a vehicle control device.

[0002]

2. Description of the Related Art In a vehicle using an automatic transmission, lock-up coupling is performed in an automatic transmission mechanism so that engine braking is actuated when an accelerator pedal is released. Here, the lockup is a mechanism that is provided in a fluid coupling (torque converter) that connects the engine and the speed change mechanism, and that directly connects the engine and the speed change mechanism.

In a vehicle control device for performing such lock-up control, as shown in, for example, Japanese Utility Model Laid-Open No. 3-36554, the rate of decrease in vehicle speed is monitored, and lock-up engagement is performed when it is determined that the vehicle is in a slow deceleration state. Is known to be done.

This is effective in a vehicle such as an FR (front engine / rear drive) vehicle in which the drive shaft is braked by the rear wheel brake having a relatively weak braking force. Generally, the braking force of the front wheel brake is stronger than that of the rear wheel brake. Therefore, in a vehicle such as an FF (front drive) vehicle that brakes the drive shaft with a strong force, the lock after the slow deceleration determination is performed. The response of the up control system is poor, and there is a high possibility that the engine will stop due to a decrease in the engine speed.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and reliably controls braking using an internal combustion engine even when panic braking is performed by a sudden braking device. Is performed and based on the determination of the brake input during deceleration,
It is intended to provide a vehicle control device that reduces engine output by unlocking the lockup of an automatic transmission and then performs throttle control to reliably prevent engine stall even during panic braking during traveling. is there.

[0006]

A vehicle control device according to the present invention is a vehicle equipped with an automatic transmission for transmitting power of an internal combustion engine to wheels, and an accelerator opening measuring means, a brake operation detecting means, and the internal combustion engine Equipped with a rotation speed measuring means, the accelerator closing detecting means detects a sudden accelerator closing operation based on the measurement information from the accelerator opening measuring means, and controls the release of the lockup of the automatic transmission according to the accelerator closing detecting operation. To do. Then, a deceleration control determination section within a predetermined time range is set from the accelerator closing operation, and when a brake-on point is detected within this deceleration control determination section, throttle control is performed and lockup control that continues the unlocked state of the lockup is performed. I try to do it.

[0007]

In the vehicle control device configured as described above,
When the accelerator is suddenly released during steady running, the accelerator closing operation is detected, the lockup of the transmission mechanism is released, and the deceleration control determination section is set. When the brake operation is not performed in accordance with such an accelerator in a normal traveling state, the lockup is released when the deceleration control section is completed, and the lockup is combined in the deceleration control section. When the pedal is depressed, the rotation speed of the internal combustion engine rapidly decreases as the vehicle speed decreases, causing an engine stall. However, when the brake is operated in the deceleration control section, the lockup of the automatic transmission is released, so that a slip occurs in the transmission unit and the occurrence of engine stall can be effectively avoided. That is, the occurrence of engine stall is avoided when the panic brake is operated during traveling, and the safe driving state is reliably ensured.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows the overall structure of an internal combustion engine.
An automatic transmission 12 is provided so as to be coupled to 11 output shafts 111. In the internal combustion engine 11,
A rotation angle sensor 13 for detecting the rotation speed, a throttle actuator 15 connected to a throttle valve 14 set in the intake pipe, a throttle opening sensor 16 connected to the throttle valve 14 to detect its opening, and the like. It is provided. Then, the rotation speed signal Ne based on the detection signal from the rotation angle sensor 13 and the throttle opening signal TA from the throttle opening sensor 16 are input to the controller 17 which is composed of a microcomputer or the like.

The automatic transmission 12 is
The lockup clutch 121 is provided, and this transmission 12 transmits the output of the output shaft 111 of the internal combustion engine 11 by fluid.
By coupling 121, the shaft output of the engine 11 is mechanically coupled to the speed change mechanism 122.

The speed change mechanism 122 constitutes a part of the automatic transmission 12, and is a mechanism for changing the shaft output of the engine 11 and outputting it. Also, this speed change mechanism
A gear 123 that rotates integrally is provided on the output shaft of the gear 122, and a vehicle speed sensor 124 that detects a pulsed signal corresponding to the rotation speed of the gear 123 is provided near the outer periphery of the gear 123. That is, the gear 123 is rotated at a speed corresponding to the wheel rotation speed, and a pulse signal corresponding to each tooth on the outer periphery of the gear 123 is input to the control device 17 as a vehicle speed detection signal SPD from the vehicle speed sensor 124. To be done.

The control device 17 includes an intake pressure signal PM from an intake pressure sensor 18 which detects an intake pipe cylinder set in the intake pipe.
Is supplied, and further, an accelerator opening signal AP from an accelerator opening sensor 19 set on the accelerator pedal, and a detection signal BR from a brake switch 20 that is connected to the brake pedal and detects when the brake is depressed are supplied. Has been done.

In the control device 17, the optimum throttle opening THC of the internal combustion engine 11 in the vehicle in which the system is mounted is based on the input information from the respective sensors.
MD is calculated, and the throttle actuator 15 is driven based on this throttle opening information to control the opening of the throttle valve 14. Further, the optimum lockup state is calculated and the drive signal LC is output to the lockup clutch 121. In addition, the optimum fuel injection amount for each cylinder is calculated according to the operating state of the internal combustion engine 11, and the opening time of the fuel injection valve 21 is controlled according to the calculated injection amount to obtain an appropriate amount. The fuel is injected into the cylinder of the internal combustion engine 11.

FIG. 2 is a functional block diagram showing such a vehicle control device. The rotational speed information Ne from the rotational speed measuring device 131 corresponding to the rotational angle sensor 13 set in the internal combustion engine 11 and the automatic transmission. 12
The vehicle speed signal SPD from the vehicle speed measuring device 125 corresponding to the vehicle speed sensor 124 of FIG.
Entered in 1. Further, throttle opening information TA from the throttle opening detection device 161 corresponding to the throttle opening sensor 16, accelerator opening information AP from the accelerator opening measuring means 191 corresponding to the accelerator opening sensor 19, and the brake switch 20. Brake ON point detection device 201 corresponding to
Brake information BR from the respective deceleration control device 171
Entered in.

The deceleration control device 171 determines the operating states of the vehicle and the internal combustion engine 11. For example, when there is a risk of engine stall such as a sudden braking operation during deceleration in the lockup state. When this is detected, a control signal is output to the throttle control device 172 and the lockup control device 173 that form the control device 17, and the lockup clutch 121 of the automatic transmission 12 is released to avoid engine stall.

A fuel control device 174 constituting the control device 17
Corresponds to the operating state of the internal combustion engine 11 based on the throttle opening information TA, the engine speed information Ne, the vehicle speed information SPD, and the intake pressure information PM from the intake load detection device 181 including the intake pressure sensor 18. The fuel injection amount is calculated and the fuel injection valve 21 is controlled. However, the F / C signal is supplied to the fuel injection valve 21 when the fuel cut (F / C) region during deceleration is determined. The injection valve 21 is closed to stop the fuel. This can reduce fuel consumption.

An outline of the operation of the vehicle control device thus configured will be described with reference to FIG. First (A)
The figure shows that in order to decelerate in a steady running state, the accelerator pedal is released first when the accelerator pedal is released.
Is set to zero. In this case, the closing speed ΔP of the accelerator opening AP (differential value of AP) ΔP is monitored, and the value of the differential value ΔP is a set value KDLTA previously obtained based on experiments or the like.
When the state of P or more is detected, it is determined that the accelerator pedal is rapidly returned. When such a rapid return operation of the accelerator pedal is detected, the determination flag XNST of the deceleration determination section within the predetermined time KJUD is detected.
Turn on AL.

In this case, the lockup clutch signal LC
Is turned off synchronously when the flag XNSTAL is turned on, and disengages the lockup clutch 121 of the automatic transmission 12 so that the lockup is released. This lockup clutch signal LC is a brake signal B while the flag XNSTAL is on.
R is being monitored, and if there is no brake operation until the flag XNSTAL is turned off, the flag XNST
In synchronization with AL, the lockup clutch signal LC is turned on after the time KJUD, and the lockup is reengaged. The throttle output TA is closed in synchronization with turning on of the lockup clutch signal LC.

FIG. 3B shows a determination flag XNSTAL in the deceleration determination section when there is a rapid accelerator return operation.
This shows a case where the brake pedal is operated while the switch is on, and the brake signal BR is turned on together with the brake pedal operation.

As described above, when the brake signal BR is turned on during the period KJUD in which the determination flag XNSTAL is turned on, it is determined that the brake is hard, and the flag XN is set in advance.
The lock-up operation that is turned off in synchronization with the rising of STAL is retained as it is after the lapse of KJUD. That is, even if the flag XNSTAL is turned off, the lockup is not recombined. By closing the throttle TA immediately in synchronization with the turning on of the brake signal BR, it is possible to prevent the braking distance from increasing.

In this way, the deceleration state is determined by the accelerator pedal device, and the deceleration determination is performed for a predetermined time XNST.
The lockup is controlled to be released within the AL range. In a normal deceleration state, after a predetermined time, the lockup is re-engaged to delay the decrease in the rotation speed of the internal combustion engine and maintain the fuel stop state for a long time to improve fuel economy. I am trying to achieve.

When a sudden braking operation is detected in the lock-up releasing section of the predetermined time,
When the lockup re-engagement is stopped, the throttle is closed in synchronization with the sudden braking, and the lockup is released. (The lockup clutch is controlled by hydraulic pressure. It takes a predetermined time after the signal operation) to avoid the engine stall.

Note that the broken line in FIG. 3B indicates that when braking is applied by sudden braking while the lockup is still engaged in the deceleration region, sudden braking is applied from the drive system to the internal combustion engine side. In addition, it shows the region where the internal combustion engine stalls.

Here, referring to FIG. 4, the fuel cut (F /
The difference in the area C) will be described in comparison with the case of the conventional lockup clutch control. It should be noted that the determination of the F / C region is generally known, and it is determined based on the throttle fully closed signal, the vehicle speed, the engine rotation speed, and the like, and at a predetermined engine rotation speed that can avoid a stall above the idle rotation speed. F / C is prohibited.

FIG. 3A shows a conventional control state, in which it is determined that the throttle opening TA is fully closed, the engine speed Ne is a predetermined value or more, and the vehicle speed is a predetermined value. When it is above (for example, 5 km / h or more), it is determined to be deceleration. Then, the F / C is permitted and the lockup is controlled to the release side (LC = 0).

By controlling in this way, the engine rotation speed Ne causes the slip in the torque converter of the transmission due to the lockup release, and the force from the vehicle side drive system to turn the engine is halved. And
F / C is prohibited while the engine rotation speed Ne is reduced to the F / C return rotation speed, and the engine rotation speed Ne stabilizes at the idle rotation speed. Therefore, F of the engine speed Ne
The F / C zone is short because the arrival time to the / C rotation speed is short.

On the other hand, in the control shown in the embodiment, as shown in FIG.
If there is no judgment of sudden braking, C is for a predetermined time XNSTA
It is re-fastened after L (LC = 1). F / C is permitted after the deceleration determination as in the case of FIG. 9A, but in this state, the lock-up clutch LC is engaged, so the engine rotation speed Ne is the same as in the conventional torque converter. In the same manner as in a manual transmission vehicle, the engine braking action gradually reduces the rotational speed Ne without causing any slip. Then, the F / C is prohibited at the F / C return rotation speed and stabilized at the idle rotation speed. In this case, the lockup clutch LC is controlled to the disengagement side at a predetermined engine rotation speed (interlocked with the F / C return rotation speed), and the F / C zone is widened as compared with FIG. Great reduction effect.

Such control is executed according to the deceleration control process stored in the deceleration control device 171, and FIG. 5 shows the flow of this deceleration control process.
The base routine of the deceleration control shown in this figure is, for example, 10
This routine is executed every m seconds, and in step 301, a deceleration-time control permission decision routine for deciding whether or not deceleration control should be carried out in accordance with the speed at which the accelerator opening moves to the closing side is called.

Next, in step 302, the presence or absence of the sudden braking operation and the sudden brake determination and lockup operation subroutine for performing the interlocking lockup clutch operation are called, and in step 303 the target throttle opening THCM.
Call the D calculation subroutine. And step 30
At step 4, an output processing subroutine for outputting the target throttle opening THCMD to the throttle control device 172 is called.

FIG. 6 shows a deceleration control permission judgment subroutine called in step 301, and this subroutine is executed every 10 ms. First, at step 401, a differential value ΔAP of the accelerator pedal opening AP is calculated every 10 ms. Specifically, when the accelerator opening 10 msec ago is BAP, the return speed of the accelerator to the closing side is obtained from the calculation formula "ΔAP = BAP-AP".

In step 402, it is judged whether or not the accelerator return speed ΔAP thus obtained is negative. If it is judged positive, it is judged that the vehicle is on the deceleration side and the routine proceeds to step 403. ΔAP is a predetermined value KDLTAP
In this determination, it is determined whether the accelerator is operated suddenly or gently. If it is determined that the accelerator is a sudden return operation, it is determined that the vehicle is decelerating, and the deceleration flag XNSTAL is set to "1" in step 404. Then, in the next step 405, the lockup clutch signal LC is set to "0" to release the lockup.

When it is determined in step 403 that the accelerator release operation is gentle, it is determined in step 406 whether the flag XNSTAL has already been set to "1", and it is determined that deceleration is in progress when "XNSTAL = 1". Then, the process proceeds to step 407 and the counter CNSTL is incremented. In step 408, it is determined whether or not this counter CNSTL has reached the predetermined time KJUD, and KJUD
If the passage of time has been satisfied, the flag XNSTAL is set to "0" in step 409.

In these steps 403-409, it is determined that the vehicle is decelerating due to a sudden accelerator return, and the flag XN is set only during the time designated by the predetermined time KJUD.
STAL is set to "1".

When ΔAP is determined to be negative in step 402, it is determined that the accelerator pedal is operated to the open side, and it is determined in steps 410 and 411 whether the opening speed is equal to or higher than the predetermined value KDLTAP2. To determine. If ΔAP is determined to be greater than or equal to this predetermined value, it is determined that the acceleration is obvious, the acceleration flag XACC is set to "1" in step 412, and the brake signal detection flag XPANI is set in steps 413 and 414.
Clear C and counter CNSTL. In this way, in steps 411 to 414, when the acceleration is determined by the operation of the accelerator opening, the deceleration control flag and the counter are cleared and the acceleration flag is set.

FIG. 7 shows the sudden braking judgment and lockup operation subroutine called in step 302, and this routine is also executed every 10 ms.
First, in step 421, it is determined whether or not the vehicle has just decelerated based on the state of the flag XNSTAL set during the deceleration determination described with reference to FIG. If the flag XNSTAL = 1
When it is determined in step 423 that the vehicle has just decelerated, the routine proceeds to step 422, where the acceleration flag XACC is cleared, and at step 423 the state of the brake switch signal BR is determined. This step 42
If it is determined in step 3 that the brakes have not been pressed, return without doing anything.

When it is determined that the brake switch signal BR = 1, it is determined that this is a sudden braking, and the step
In step 424, the brake signal detection flag XPANIC is set to "1", and in step 425, the lockup clutch operation instruction is set to LC = 0 to perform the lockup release operation.

In step 421, the flag XNSTAL is set.
Is determined to be "0", the state of the brake signal detection flag XPANIC is determined in step 426, and if it is determined that the brake is depressed, the lockup is released in step 425. After this brake signal detection flag is set at XPAN = 1, B
Even if R = 0, it does not become XPANIC = 0 and is not cleared until the next acceleration judgment XACC = 1 (step of FIG. 6).
413).

When it is determined in step 426 that XPANIC = 0, it is determined that no sudden braking has occurred, and in step 427, the acceleration determination flag XACC is determined. If it is determined in step 426 that the vehicle is not accelerating, lockup is engaged (LC = 1) in step 428. If the acceleration state is determined in step 427, the process directly returns to the subroutine.

FIG. 8 is a timing chart for explaining such a control flow. The differential signal .DELTA.AP is generated with the accelerator pedal released, and the flag XNSTAL for judging the deceleration is "1". If the brake switch signal BR = 1 is determined in the state, even if the brake switch signal becomes “0”, the state of the brake determination flag XPANIC = 1 indicates the next acceleration determination XACC.
It is maintained until = 1. Then, during this acceleration determination flag XACC = 0, LC = 0 is set and lockup is not re-engaged.

If the brake switch signal BR = 1 is not judged in the state of the deceleration judgment flag XNSTAL = 1, LC = 1 is set in synchronization with the deceleration judgment flag XNSTAL = 0 and the lockup is restarted. Fastening will begin (steps 426-428).

FIG. 9 shows a subroutine for calculating the target throttle opening THCMD which is called in the base routine 303, and this routine is also executed every 10 ms. First, in step 431, the deceleration determination flag XNST
It is determined whether or not the vehicle is in the deceleration state by checking the AL state. If it is determined in step 431 that XNSTAL = 0 and it is not immediately after deceleration, the counter CAP is cleared in step 432, and the accelerator opening AP at that time is set to the target throttle opening THCMD in step 433.
Memorize as.

Immediately after deceleration (XNST
If it is determined that AL = 1), it is determined in step 434 whether CAP = 0 or not.
It is determined whether or not step 434 is passed for the first time after STAL = 1. If it is the first time, the deceleration determination flag XNSTAL is set from 0 to 1 in step 435.
The accelerator opening AP at which the acceleration becomes, that is, the accelerator opening AP synchronized with the deceleration determination is stored in a storage device called MAP. When the relationship of CAP = 1 is determined in step 434, the step 435 is bypassed and the process proceeds to step 436 to increment the counter CAP.

In the next step 437, it is determined whether or not the brake determination flag XPANIC = 1, and if it is determined that the brake is not depressed, step 438.
In step 435, the accelerator opening at the time of deceleration determination stored in MAP is set as the target throttle opening THCMD.

That is, deceleration determination flag XNSTAL =
When the deceleration is determined by 1, the throttle opening TA is maintained at the value of MAP in the section of XNSTAL = 1 (for KJUD time) when the sudden braking is not operated.
Then, in synchronization with XNSTAL = 0, the throttle opening TA is returned to the accelerator opening AP at that time.

If the deceleration determination flag XNSTAL = 1 and a sudden brake is applied, the brake determination flag X
The throttle opening TA is immediately returned to the accelerator opening AP in synchronization with PANCI = 1. If deceleration is not determined, the throttle TA is operated with the same value as the accelerator opening AP.

In this way, the lockup operation in the deceleration region shown in FIG. 3 is performed, and in the normal deceleration state, the fuel consumption is improved by engaging the lockup, and when the sudden braking is applied, the lockup is performed. Due to the delay of the release and the throttle operation, the engine stall will be avoided.

In the embodiment, the accelerator opening AP
Deceleration is determined based on the differential value ΔAP of
In this case, the deceleration determination may be performed based on the differential value of the throttle opening. Further, the deceleration can be determined by the differential value of the decrease in the rotation speed of the internal combustion engine or the differential value of the decrease in the vehicle wheel speed.

Further, the judgment of the sudden braking is made by the brake switch signal BR, but the judgment of the sudden braking can also be carried out in the same manner by making the judgment of the sudden braking by the differential value of the decrease of the rotational speed of the internal combustion engine and the wheel speed. Further, a section for determining the presence or absence of sudden braking, that is, the flag XNSTAL =
The section in the state of 1 is set to a fixed value of KJUD, but it may be variable depending on the operating state of the internal combustion engine or the operating state of the vehicle. Control and management of braking distance can be performed.

[0048]

As described above, according to the vehicle control device of the present invention, the braking control using the internal combustion engine is surely performed even when the panic braking by the sudden braking device is performed. Based on the judgment of the brake input during deceleration, etc., the engine output is reduced by releasing the lock-up of the automatic transmission and then performing the throttle control to reliably prevent engine stalling even during panic braking during running. it can.

[Brief description of drawings]

FIG. 1 is a configuration diagram illustrating a vehicle control device according to an embodiment of the present invention.

FIG. 2 is a configuration diagram illustrating a control unit of the above embodiment.

FIGS. 3A and 3B are timing charts illustrating operating states during steady state and during sudden braking.

FIGS. 4A and 4B are timing charts showing the conventional control state and the control state in the embodiment for comparison.

FIG. 5 is a diagram illustrating a control routine of a deceleration process according to this embodiment.

FIG. 6 is a flowchart illustrating a deceleration control permission determination subroutine in this control routine.

FIG. 7 is a flowchart similarly illustrating a sudden braking determination subroutine.

FIG. 8 is a timing chart illustrating this subroutine.

FIG. 9 is a flowchart illustrating a target throttle opening calculation subroutine of the control routine.

[Explanation of symbols]

11 ... Internal combustion engine, 12 ... Automatic transmission, 121 ... Lockup clutch, 124 ... Vehicle speed sensor,
13 ... Revolution sensor, 14 ... Throttle valve, 15 ... Throttle actuator, 16 ... Throttle opening sensor, 17 ... Control device, 19 ... Accelerator opening sensor, 20 ... Brake switch, 21 ... Fuel injection valve, 171 ... Deceleration control apparatus.

Claims (1)

[Claims] 1. An automatic transmission for transmitting power of an internal combustion engine to wheels, an accelerator opening measuring means for measuring an accelerator opening corresponding to an operation amount of an accelerator pedal, and a brake operation for detecting a stepping operation point of a brake pedal. Detecting means, rotational speed measuring means for measuring the rotational speed of the internal combustion engine, accelerator closing detecting means for detecting a sudden accelerator closing operation based on measurement information from the accelerator opening measuring means, and the accelerator closing A deceleration control section setting means for setting a judgment section within a predetermined time range from operation, and a brake on for detecting a detection by the brake operation detection section in the deceleration control judgment section and detecting a brake operation in the judgment section. Point detection means, and the automatic transmission according to the accelerator closing detection Lockup control means for controlling the lockup to be released, coupling the released lockup with the end of the determination section of the deceleration control, and continuing the released state of the lockup with the detection of the brake-on point; And a throttle control means for controlling a throttle opening based on a detection signal from the brake-on point detection means, wherein the lockup is held in a released state at the time of sudden braking accompanied by a brake operation. And a vehicle control device.