JPH03258932A - Slip control device - Google Patents

Abstract

PURPOSE:To prevent shortage of a feeling of acceleration by decreasing the reduced amount of engine output obtained by an output control means at the time of slip control below that at the time of usual travel when an ascending slope travel of a vehicle is confirmed from a signal of an inclination degree detecting means. CONSTITUTION:A control unit UTR for slip control performs control of braking force of rear wheels 2L, 2R at the time when a slip occurs, and it simultaneously performs output control for reducing driving torque of an engine 3. When it is confirmed that a vehicle travels on an ascending slope, in accordance with a detection signal of an inclination degree detecting means 46, the controlled amount of engine output at the time of slip control, that is, the throttled amount of a sub-throttle opening adjusting mechanism 34 is reduced compared to that at the time of usual travel. Thus, the following disorders can be prevented: engine output is largely decreased at the time when the vehicle travel on an ascending slope; a feeling of acceleration is lost due to shortage of driving torque of driving wheels; rapid acceleration is unable to be obtained at the time when the vehicle is accelerated again.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention provides slip control that prevents excessive slip of the drive wheels during acceleration by controlling the torque applied to the drive wheels when the vehicle is running. It is related to the device.

[Conventional technology]

Conventionally, as shown in Japanese Unexamined Patent Publication No. 62-251268, when the slip ratio of the driving wheels to the road surface exceeds a predetermined value when the vehicle is accelerating, the output of the engine is reduced and control is applied to the driving wheels. By applying power, the driving torque of the wheel is reduced to restore the grip force, thereby suppressing wheel slibbing.

[Problem to be solved by the invention]

As mentioned above, in a vehicle equipped with a slip control function that suppresses excessive slip of the drive wheels against the road surface by reducing engine output and wheel drive torque, when the vehicle is traveling uphill, When the above-mentioned slip control is executed, there is a problem in that the driving torque of the wheels is insufficient and the feeling of acceleration is likely to be impaired. That is, when traveling uphill, the traveling resistance increases by the slope resistance corresponding to the degree of inclination, so if the engine torque is reduced in the same way as when traveling on a level road, there is a possibility of deceleration.

In addition, once the engine torque is reduced by closing the throttle valve to suppress the above-mentioned slip, even if the throttle valve is opened again, the engine torque cannot be increased immediately, resulting in stalling when driving uphill with high running resistance. There is a problem in that it tends to cause feelings of discomfort.

The present invention has been made to solve the above-mentioned problems, and provides a slip control device that can prevent a lack of acceleration feeling due to excessive reduction in engine output when driving uphill. It is an object.

[Means to solve the problem]

The invention described in claim 1 includes an engine output control means and a drive wheel braking force control means, and controls the torque applied to the drive wheels to prevent excessive slip of the drive wheels during acceleration. In a slip control device that prevents a vehicle from traveling uphill, the system includes a slope detection means for detecting the slope of a running road, and a slope detection means that detects a slope of the vehicle. The vehicle is further provided with control state changing means for reducing the amount of reduction in engine output during slip control by the output control means compared to during normal driving.

The invention described in claim 2 has an engine output control means and a drive wheel braking force control means, and controls the torque applied to the drive wheels to prevent excessive slip of the drive wheels during acceleration. In a slip control device that prevents a vehicle from traveling uphill, the system includes a slope detection means for detecting the slope of a running road, and a slope detection means that detects a slope of the vehicle. Control state changing means is provided for reducing the amount of reduction in engine output during slip control by the output control means compared to during normal driving, and for setting a target value for control by the braking force control means to a lower value. It is.

[For production]

According to the present invention as set forth in claim 1 above, when it is confirmed that the vehicle is traveling uphill according to the detection signal of the slope detection means, the engine output control amount during slip control is is reduced compared to when driving normally, and a large drop in engine output is prevented when driving uphill.

Further, according to the present invention as set forth in claim 2, the lack of slip control action due to the reduction in the amount of decrease in engine output during uphill running can be resolved by performing braking force control earlier than during normal running. This will be supplemented by

〔Example〕

FIG. 1 shows a vehicle equipped with a slip control device according to the invention. This vehicle has left and right front wheels I that are driven wheels.
L, IR, and left and right rear wheels 2L and 2R that serve as driving wheels, and the driving force of the engine 3 is transmitted through an automatic transmission 4, a propeller shaft 5, a differential 6, and left and right axles 7L,
The signal is configured to be transmitted to the rear wheels 2L and 2R via 7R.

The automatic transmission 4 includes a torque converter 8 as is known in the art.
and a multi-speed gear mechanism 9, and a plurality of solenoids 10 incorporated in the hydraulic circuit of the multi-speed gear mechanism 9.
Shifting is performed by changing the combination of excitation and demagnetization. Further, the torque converter 8 has a hydraulically operated lock-up clutch 11, and is engaged and disengaged by switching between excitation and demagnetization of a solenoid 12 incorporated in the hydraulic circuit. ing.

The solenoid 10.12 is controlled in accordance with a control signal output from a control unit (not shown) for speed change control. This control unit is a control unit for executing predetermined speed change control and lock-up control based on preset speed change characteristics and lock-up characteristics, and detection signals output from a throttle opening sensor and a vehicle speed sensor. It is configured to output a signal to the solenoid 10.12.

In addition, for the front wheels IL and IR and the rear wheels 2L and 2R,
Brakes 15a-15d are respectively provided, and brake pressure supply piping 17a-17d is connected to calipers 16a-16d of each brake 15a-15d.

The depression force of the brake pedal 18 is then boosted by a hydraulic pressure booster 19 and transmitted to the mask cylinder 20, from the first discharge port 21a of the mask cylinder 20 via the pipe 17a to the caliper of the left front wheel IL. Brake fluid pressure is supplied to the caliper 16a, and the brake fluid pressure is supplied from the second discharge port 21b of the mask cylinder 20 to the caliper 16b of the right front wheel IR via the pipe 17b.

The booster 19 is supplied with hydraulic pressure from a pump 23 via a pipe 22, and the excess hydraulic pressure is transferred to the return pipe 22.
4 and is returned to the reserve tank 25. A branch pipe 22a branched from the pipe 22 is connected to a confluence G with a pipe 27 described later, and the branch pipe 22a
An electromagnetic on-off valve 26 is provided. Further, the boosting hydraulic pressure generated in the booster 19 is transferred to the piping 27.
It is designed to be supplied to the above-mentioned confluence section G via
This piping 27 is provided with an electromagnetic on-off valve 28 .

The piping 27 has a one-way valve 2 that allows the brake oil to flow toward the confluence G side and prevents the flow in the opposite direction.
9 is provided in parallel with the electromagnetic on-off valve 28.

Brake pipes 17c and 17d for the left and right rear wheels 2L and 2R are connected to the merging part G, and these pipes 17c and 17d
are provided with electromagnetic on-off valves 29A and 30A.

And on the downstream side of the installation part of the electromagnetic on-off valve 29A,
A relief passage 31L having an electromagnetic on-off valve 29B is provided, and downstream of the installation part of the electromagnetic on-off valve 30A,
A relief passage 31R having an electromagnetic on-off valve 30B is provided.

Each of the above on-off valves 26.28, 29A, 29B, 30A, 3
0B constitutes a braking force control means 32 for the rear wheels 2L and 2H, and is controlled by a control unit UTR for slip control. When slip control is not performed, the on-off valve 26 is closed and the on-off valve 28 is closed, as shown in the figure.
is opened, and the on-off valves 29A and 30A are opened.

Thereby, when the brake pedal 18 is depressed, brake fluid pressure is supplied from the master cylinder 20 to the brakes 15a and 15b for the front wheels IL and IR.

Further, boosting hydraulic pressure from the hydraulic pressure booster 19 is supplied to the rear wheel brakes 15c and 15d as brake hydraulic pressure via a pipe 27.

In addition, when performing slip control for rear wheels 2L and 2R,
The on-off valve 28 is closed and the on-off valve 26 is opened in response to a control signal from the control unit UTR. The brake fluid pressure is maintained, raised, and lowered by duty-controlling the on-off valves 29A, 29B, and 30A, 30B, respectively. That is, with the on-off valve 26 open, each on-off valve 29A
.

Brake fluid pressure is maintained when 29B, 30A, and 30B are closed. In addition, the on-off valves 29A and 30A open,
When the on-off valves 29B and 30B are closed, the brake fluid pressure is increased, and the on-off valves 29A and 30A are closed.
When the on-off valves 29B and 30B are open, the brake fluid pressure is reduced. The brake fluid pressure passing through the branch pipe 22a is prevented from acting as a reaction force on the brake pedal 18 due to the bypass action of the one-way valve 29.

Note that when the brake pedal 18 is depressed while slip control is being performed by the braking force control means 32, the brake fluid pressure from the booster 19 is applied to the rear via the one-way valve 29 in response to the depression. wheel brake 1
5c and 15d.

The slip control control unit UTR executes braking force control by applying braking force to the rear wheels 2L and 2R as described above in order to reduce the torque applied to the rear wheels 2L and 2R when a slip occurs. At the same time, output control is executed to reduce the driving torque of the engine 3. This output control is performed by a sub-throttle opening adjustment mechanism 34 disposed in the intake passage 33 of the engine 3. This sub-throttle opening adjustment mechanism 34 includes a sub-throttle valve 37 disposed upstream of a throttle valve 36 that is opened and closed by an accelerator pedal 35, and an actuator 38 that drives this sub-throttle valve 37. . When a slip occurs, the output of the engine 3 is controlled by opening and closing the sub-throttle valve 37 in response to a control signal output from the control unit UTR to the actuator 38.

The slip control control unit UTR includes wheel speed sensors 39a to 39d that detect the rotational speed of each wheel IL, IR, 2L, and 2R, a throttle valve sensor 40 that detects the opening degree of the throttle valve 36, and a throttle valve sensor 40 that detects the vehicle speed. A vehicle speed sensor 41, a sub-throttle valve sensor 42 that detects the opening degree of the sub-throttle valve 37, a steering angle sensor 43 that detects the steering angle, a switch 44 that is used to manually set the driving mode, etc., and a brake pedal. Output signals from a brake sensor 45 that detects that the brake pedal 18 is depressed and an inclination sensor 46 that detects the inclination of the road on which the vehicle travels are input.

Then, according to each of the above output signals, the control unit UTR
, the slip values of the rear wheels 2L and 2R are calculated, and according to the calculation results, the slip values of the rear wheels 2L and 2R are calculated as shown in FIG.
Slip control consisting of braking force control and output control of the engine 3 is executed.

Further, in the control state changing means 47 provided in the control unit UTR, the vehicle travels uphill at a preset reference angle or more in response to an output signal from the slope detecting means comprising the slope sensor 46. If it is confirmed that the brake force control means 32 and the output control means constituted by the sub-throttle opening adjustment mechanism 34 are changed as described later, the control states of the output control means and the braking force control means 32 are changed.

In FIG. 2, SS indicates a reference slip value that is used as a criterion for determining whether or not to start slip control of the rear wheels 2L and 2H. When the vehicle is accelerating, the sub-throttle valve 37 is maintained at the maximum open state, and the sub-throttle valve 37 is maintained at the maximum open state, and the throttle valve 36 is The opening degree Tn of the intake passage 33 is set according to the opening degree. That is, the opening degree Tn of the intake passage 33 is set according to the opening degree TH-B of the throttle valve 36, which is opened and closed in accordance with the amount of depression of the accelerator pedal 35, and the output control of the engine 3 is executed.

Then, as the rotational speed of the rear wheels 2L and 2R increases, the slip value thereof increases, and the reference value S at the time of starting the slip control is
At the time t□ when S or more, the actuator 38
is activated, and feedford control is executed to reduce the opening degree of the sub-throttle valve 37 by a preset initial setting value SM. As a result, the opening degree of the sub-throttle valve 37 becomes smaller than the opening degree of the throttle valve 36, and the opening degree Tn of the intake passage 33 is set in accordance with the opening degree of the sub-throttle valve 37. After that, rear wheels 2L, 2R
The slip value is the target value S for engine output control, which will be described later.
The opening degree T of the sub-throttle valve 37 is set so that ET.
HM is feedback controlled.

Also, from the start time t1 of the slip control, the rear wheels 2L, 2
At time t2 when the slip value of R further increases and exceeds a target value SBT for braking force control, which will be described later, rear wheels 2L,
Brake oil is supplied to the brakes 15c and 15d of the 2H, and the rear wheels 2L and 2R are supplied with brake oil until the slip value of the rear wheels 2L and 2R reaches the time t3 when the slip value of the rear wheels 2L and 2R becomes equal to or less than the target value SBT.
The braking force is feedback controlled.

Next, details of the slip control by the control unit UTR will be explained based on the flowchart shown in FIG. When the above control operation starts, first step S1
, each data is input based on signals from each sensor and switch. Next, in step S2,
The slip value S of the rear wheels 2L, 2R is calculated by subtracting the rotational speed VJ of the front wheels IL, IR, which are driven wheels, from the rotational speed VK of the rear wheels 2L, 2R, which are driving wheels.

When calculating this slip value S, the average value of the rotational speeds of the left and right front wheels IL and IR is used as the rotational speed VJ for the driven wheels. Further, as the rotational speed VK for the driving wheels, the larger value of the rotational speeds of the left and right rear wheels 2L and 2R, or the individual rotational speeds of the left and right rear wheels 2L and 2R is used.

Next, in step S3, it is determined whether the accelerator is in a fully closed state. If it is confirmed that the accelerator is not in a fully closed state but in a predetermined acceleration state, in step S4, it is determined whether the slip flag SF is 1, that is, whether slip control is currently being executed. Determine whether

As a result of this determination, if it is confirmed that slip control is not being executed, in step S5, the rear wheel 2L
It is determined whether the slip value S of , 2R is equal to or greater than a preset reference value SS (usually about 20%) for starting slip control. If the determination in step S5 is YES, the slip flag SF is set to OFF in step S6, and the output control of the engine 3 is executed in step S7. Executes 2R braking force control.

If the determination in step S4 is YES and it is confirmed that slip control is currently being performed, the process moves to step S7 to continue slip control. Further, in step S3, it is determined that the accelerator is fully closed, or in step S5, it is determined that the slip value S of the rear wheels 2L and 2R is smaller than the reference value SS for starting slip control, and slip control is executed. If it is confirmed that there is no need, the slip flag is set to 0 in step S9, and then the process returns.

The engine output control described above will be explained based on the flowchart shown in FIG. First, in step S11,
It is determined whether or not the slip flag has changed from O to 1 at the present time, that is, whether or not the present time is the start time t1 of the slip control shown in FIG. This judgment result is YES
If so, in step S12, it is determined whether the vehicle is currently traveling uphill. That is, it is determined whether the vehicle is running uphill by comparing the slope of the road detected by the slope sensor 46 with a preset reference slope.

If it is confirmed in step S12 that the vehicle is not in an uphill running state, then in step S13, the sub-throttle valve 37 is set to
After reading out the initial setting value, that is, the sudden decrease SM1 of the subthrottle opening at the start of slip control, step S14
In this step, the actuator 38 is operated according to the initial setting value SM1, and the opening degree of the sub-throttle valve 37 is reduced to control the opening degree Tn of the intake passage 33.

Further, if it is confirmed in step S12 that the vehicle is running uphill, in step S15,
After reading the initial setting value SM2 of the sub-throttle valve 37, which is set to have a smaller rapid decrease in sub-throttle opening than the initial setting value SMl during normal driving, step S1
Move to 4.

Further, if the determination in step S11 is No and it is confirmed that slip control has already been started, a target value SET for engine output control is set in step S16. In other words, as shown in Figure 5,
The basic slip value 5T corresponding to the current driving condition is determined from the map of the basic slip value 5TAO for engine output control, which is stored using the maximum friction coefficient μmax of the road surface as a parameter.
Read the value of AO. A map of gain coefficient VG with vehicle speed as a parameter shown in Fig. 6, a map of gain coefficient ACPG with accelerator opening as a parameter shown in Fig. 7, and a gain coefficient S with steering angle as a parameter shown in Fig. 8.
Each gain coefficient is read out from the TRG map and the gain coefficient MODEC table corresponding to the driving mode selected according to the driver's switch operation shown in Fig. 9, and these values are multiplied by the above basic slip value 5TAO. By matching, the target value SET for engine output control
seek.

Next, in step S17, it is determined whether the slip ratio S of the rear wheels 2L, 2R is larger than the target value SET. If it is determined in this step S17 that the slip rate S is less than or equal to the target value SET, the process proceeds to step S18, where the slip flag SF is set to 0 and the slip control is ended.

If it is determined in step S17 that the slip ratio S of the rear wheels 2L and 2H is larger than the target value SET,
In step S19, it is determined whether or not the vehicle is currently in the hypothetical uphill running state. If it is confirmed that the vehicle is not in the hypothetical uphill running state, in step S19, as shown in FIG. Maximum friction coefficient μm a x
From the first map set as a parameter, the sub-throttle opening TH-Ml corresponding to the driving condition of the vehicle, that is, the slip value S during normal driving mentioned above, is set to the target value SE.
After reading the amount of operation of the actuator 38 necessary to make the opening Tn equal to or less than T, the process proceeds to step S14, where the actuator 38 is operated to control the opening degree Tn of the intake passage 33.

Further, if it is confirmed in step S19 that the vehicle is in the hypothetical uphill running state, then in step S21 the subthrottle opening degree is set to a larger value than in the first map, as shown in FIG. The sub-throttle valve 37 corresponds to the running condition of the vehicle based on the set second map.
After reading out the opening degree TH·M2, that is, the operation amount of the actuator 38 necessary to make the slip value S less than the target value SET when traveling uphill, the process proceeds to step S14.

Next, the braking force control of the rear wheels 2L and 2R will be explained based on the flowchart shown in FIG. 12.

When this braking force control starts, first step S21
, it is determined whether the vehicle is currently in a hypothetical uphill traveling state. If it is confirmed that the vehicle is not in the uphill traveling state, a target value 5BTI for braking force control during normal running is determined in step S22. That is, as shown in Fig. 13, the maximum friction coefficient μ of the road surface
Of the two types of basic slip values 5TBOI and 5TBO2 for braking force control stored with max as a parameter,
Read out the larger basic slip value 5TBOI, multiply this value by each gain coefficient shown in Figures 5 to 8, and obtain the target value 5B for braking force control during normal driving.
Calculate TI.

Next, in step S23, it is determined whether the slip value S of the rear wheels 2L, 2R is larger than the target value 5BTI, and if the determination is YES, in step S24, the slip value S is set to be equal to or lower than the reference value 5BT1. Execute braking force control to achieve this. In addition, the above step 323
If it is determined in step S25 that the slip amount S is less than or equal to the reference value 5ETI, it is determined in step S25 whether or not braking force control is currently being executed.

If this determination is YES, in step S26, the braking force is gradually reduced and the braking force control is ended. Note that if the determination in step S25 is No,
Return as is.

Further, in step S21, if it is confirmed that the vehicle is in the uphill hypothetical state, step S27
Based on the basic slip value 5TBO2 shown in FIG.
In other words, after determining the target value 5BT2 which is set lower than the target value 5BTI during normal driving, in step S28, it is determined whether the slip values S of the rear wheels 2L and 2R are larger than the target value 5BT2. Determine.

If it is confirmed that the slip rate S is larger than the target value 5BT2, the process proceeds to step S24, where braking force control is executed to make the slip value S equal to or less than the target value 5B72. If it is determined in step 328 that the slip value S is less than or equal to the target value 5ET2, the process proceeds to step S25.

As mentioned above, there are two types of initial setting values for engine output control at the start of slip control: large and small values SMI and S.
M2 is provided, and the smaller initial setting value SM is set when driving uphill.
Since the output control of the engine 3 is configured to be executed based on 2, it is possible to prevent the engine output from decreasing excessively when slip control is started in an uphill running state. That is, in an uphill running state, the sudden decrease in subthrottle opening is set to be smaller than in normal running, so the amount of decrease in engine output is reduced. Therefore, when driving uphill, the rear wheel 2L
, 2R can effectively prevent the sense of acceleration from being impaired due to insufficient driving force.

In addition, as described above, in the slip control device that is provided with two types of initial setting values SMI and SM2 for engine control, two types of target values 5BTI and 5BT2 are provided for braking force control, and control during uphill driving is provided. Target value 5B for power control
If TI is set lower than the target value 5BT2 during normal driving, braking force control for the rear wheels 2L and 2R will be executed early. Therefore, the braking force control can compensate for the lack of slip control effect caused by reducing the initial set value SM2 for engine output control during uphill driving to reduce the amount of engine output reduction during slip control. . Therefore, it is possible to appropriately perform slip control that suppresses slip of the driving wheels while preventing a lack of acceleration feeling when traveling uphill.

Note that two types of values are provided as the target value SET for engine output control, and the target value for uphill driving may be set larger than that for normal driving. In this case, the slip of the drive wheels during uphill driving When the value decreases to a certain extent, the output control of the engine 3 is stopped earlier than during normal driving, so there is an advantage that it is possible to prevent the engine output from decreasing excessively during slip control.

Further, in the above embodiment, the subthrottle opening adjustment mechanism 3
Although an example has been described in which the engine output is controlled during slip control by the output control means consisting of 4, an ignition timing control means for the engine 3 may be provided in addition to the sub-throttle opening adjustment mechanism 34. That is,
The ignition timing is determined according to the detection signal output from the throttle valve sensor 40 and the detection signal output from the rotation sensor that detects the rotation speed of the engine 3, and a control signal based on this is sent to the igniter of the engine 3. The configuration may be such that output control of the engine 3 during slip control is performed by outputting and retarding the ignition timing.

〔Effect of the invention〕

As explained above, the present invention is configured to reduce the amount of reduction in engine output during slip control by the engine output control means when traveling uphill compared to when traveling normally. This has the advantage that it is possible to effectively prevent the feeling of acceleration from being impaired due to insufficient driving torque, or from being inhibited from rapid acceleration during re-acceleration.

In addition, in the slip control device equipped with the engine output control means configured as described above, the reference value for control by the braking force control means is set to be lower when driving uphill, and the braking force control is executed earlier than during normal driving. When configured to do so, the lack of slip control action due to the reduction in the control amount of the engine output control means is compensated for by braking force control,
This has the advantage that slip control can be appropriately executed while preventing a lack of sense of acceleration when driving uphill.

[Brief explanation of drawings]

Fig. 1 is an overall system diagram showing an embodiment of the slip control device according to the present invention, Fig. 2 is a time chart showing an overview of slip control, Fig. 3 is a flow chart showing the control operation of the slip control device, and Fig. 4 5 is a flowchart showing the engine output control operation, FIG. 5 is a map showing the relationship between the basic setting value for engine control and the maximum friction coefficient μmax, and FIG.
The figure shows a map showing the gain coefficient with vehicle speed as a parameter.
Figure 7 is a map showing gain coefficients using accelerator opening as a parameter, Figure 8 is a map showing gain coefficients using steering angle as a parameter, Figure 9 is a chart showing gain coefficients corresponding to driving modes, and Figure 10. is a map showing the sub-throttle opening in normal driving conditions, Fig. 11 is a map showing the sub-throttle opening in a hypothetical uphill load, Fig. 12 is a flowchart of braking force control operation, and Fig. 13 is a map showing the maximum friction of the road surface. This is a map showing basic slip values for braking force control using coefficient μmax as a parameter. IL, IR... Driven wheel (front wheel), 2L, 2R... Driving wheel (rear wheel), 3... Engine, 32... Braking force train means, 34... Output control means (subthrottle opening adjustment mechanism), 46... inclination angle detection means (inclination sensor), 47... control state changing means.

Claims (1)

[Scope of Claims] 1. It has an engine output control means and a drive wheel braking force control means, and controls the torque applied to the drive wheels to prevent excessive slip of the drive wheels during acceleration. The slip control device includes a slope detection means for detecting the slope of the running road, and when it is confirmed that the vehicle is traveling uphill according to the detection signal of the slope detection means, the above output is output. 1. A slip control device comprising control state changing means for reducing the amount of reduction in engine output during slip control by the control means compared to during normal driving. 2. A slip control device that includes an engine output control means and a drive wheel braking force control means, and controls the torque applied to the drive wheels to prevent excessive slip of the drive wheels during acceleration, A slope detection means for detecting the slope of the running road, and a slip control by the output control means when it is confirmed that the vehicle is traveling uphill according to an output signal from the slope detection means. A slip control device comprising control state changing means for reducing the amount of reduction in engine output during normal driving compared to when driving, and for setting a target value for control by the braking force control means to a lower value. .