JP2887998B2 - Traction control device for vehicles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a traction control device for a vehicle that suppresses acceleration slip by using both output control of an internal combustion engine and brake control.

[0002]

2. Description of the Related Art Conventionally, as a traction control device for a vehicle for suppressing acceleration slip by using both output control of an internal combustion engine and brake control, for example, Japanese Patent Application Laid-Open No. 61-8524 is known.
The device described in Japanese Patent Publication No. 8 is known.

The above-mentioned conventional source discloses a technique for suppressing acceleration slip by using both throttle control (output control of the internal combustion engine) and brake control when an acceleration slip occurs.

[0004]

However, in the traction control device for a vehicle described above, the control gains of the throttle control and the brake control are always kept in a predetermined relationship, so that the control gains are appropriately set for the following reasons. Considerable tuning is required to set the gain that seems to be.

(1) If the brake control gain is set to a relatively large value in order to obtain control responsiveness, the brake will always be controlled with a slight drag, causing early wear of the brake pad and the like, resulting in poor brake durability.

(2) On the other hand, if the throttle control gain is set to a relatively large value for protection of the brake, control responsiveness cannot be obtained, and the vehicle stability is reduced.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems. In a traction control device for a vehicle which suppresses acceleration slip by using both output control of an internal combustion engine and brake control at the time of acceleration slip control, A first object is to achieve both high control responsiveness and brake protection.

A second object of the present invention is to solve the above-mentioned problem every time an acceleration slip occurs when the acceleration slip occurs a plurality of times during traveling.

[0009]

In order to solve the above-mentioned first problem, in the vehicle traction control device according to the present invention, the brake control gain is increased in the first cycle of the control requiring control responsiveness, and After the cycle, the control gain of the brake control is made relatively smaller than the control gain of the output control of the internal combustion engine to perform the acceleration slip control.

That is, as shown in the claim correspondence diagram of FIG. 1, an acceleration slip internal combustion engine output control system a for reducing the internal combustion engine output in order to suppress the acceleration slip according to the occurrence of the acceleration slip, The acceleration slip brake control system b for applying a braking force to the drive wheels to suppress the acceleration slip according to the situation, the acceleration slip control cycle number calculation means c for calculating the number of acceleration slip control cycles, and the number of acceleration slip control cycles the first period is pressurized each control gain <br/> internal combustion engine output control and brake control
Control responsiveness that can follow overshoot of fast slip
And an acceleration slip control means e for making the control gain of the brake control relatively smaller than the control gain of the internal combustion engine output control after the second control cycle. .

In order to solve the above second problem, a control cycle number clearing means d for clearing the control cycle number when the acceleration slip control is not performed for a predetermined time is provided.

[0012]

According to the first aspect of the invention, when the acceleration slip is generated and the acceleration slip control cycle number calculating means c calculates that the number of control cycles of the acceleration slip is the first cycle, the acceleration slip control means e sends the acceleration slip control cycle number. Acceleration switch
Has control response that can follow overshoot of lip
With the normal control gain, the acceleration slip internal combustion engine output control system a and the acceleration slip brake control system b are operated, and the acceleration slip control cycle number calculation means c calculates that the number of control cycles of the acceleration slip is after the second cycle. At times, in response to a command from the acceleration slip control means e, the control gain of the brake control is relatively reduced, and the acceleration slip internal combustion engine output control system a and the acceleration slip brake control system b are operated.

Accordingly, in the first cycle of the control cycle in which the acceleration slip overshoots, the control response is obtained by operating the acceleration slip brake control system b with the normal control gain, and the acceleration slip is reduced. In the second and subsequent cycles of the converging control cycle, the control gain is reduced and the acceleration slip brake control system b is operated to reduce the brake load and protect the brake.

According to the second aspect of the present invention, if the acceleration slip control is not performed for a predetermined time while the vehicle is running without occurrence of the acceleration slip, the control cycle number clearing means d sets the number of control cycles of the acceleration slip control. Cleared.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration will be described.

FIG. 2 is an overall view of a braking / drive system control system for a rear wheel drive vehicle to which the vehicle traction control device according to the embodiment of the present invention is applied.

This rear wheel drive vehicle has a throttle control for controlling a motor throttle opening degree so that a rear wheel slip ratio is within an optimum allowable range when an acceleration slip occurs, and is independent for right and left rear wheels when an acceleration slip occurs. And a traction control system that uses brake control to apply braking force (the throttle control side is equivalent to an acceleration slip internal combustion engine output control system, and the brake control side is equivalent to an acceleration slip brake control system). An anti-skid brake control system that controls the front and rear wheel brake pressure so as to prevent wheel lock during slip is mounted. The centralized electronic control of these systems is based on the traction control system & anti-skid brake control system electronic control unit TCS / ABS-ECU
TCS / ABS-ECU).

The TCS / ABS-ECU has a right front wheel speed sensor 1
From the right front wheel speed sensor value VWFR, the left front wheel speed sensor value VWFL from the left front wheel speed sensor 2, the right rear wheel speed sensor value VWRR from the right rear wheel speed sensor 3, and the Left rear wheel speed sensor value VWRL, lateral acceleration sensor value YG from lateral acceleration sensor 5, switch signal SWTC from TCS switch 6, switch signal SWST from brake lamp switch 7, throttle control module TCM (hereinafter, referred to as Throttle 1 actual opening DKV from TCM)
And the automatic transmission control unit A /
Gear position signal and shift-up signal from TC / U (hereinafter abbreviated as A / TC / U) and engine rotation from ECCS C / U (hereinafter abbreviated as ECCS C / U) A number signal, a second throttle signal TVO2 from the second throttle sensor 17, and the like are input.

From the TCS / ABS-ECU, an acceleration slip is detected and the throttle 2 as a throttle opening / closing signal is detected.
The target opening DKR is output to the TCM, and a solenoid signal as a brake pressure increase / decrease signal is output to each solenoid valve of the common hydraulic unit TCS / ABS-HU (hereinafter abbreviated as TCS / ABS-HU). . Of the traction control, the throttle control side is called TCS throttle control, and the brake control side is called TCS brake control.

The TCS / ABS-ECU detects a deceleration slip and outputs a solenoid signal as a brake pressure increasing / decreasing signal to each solenoid valve of the TCS / ABS-HU. This anti-skid brake control is called ABS brake control.

In addition to the above output, the TCS / ABS-ECU outputs a lighting command to the TCS fail lamp 14 when the TCS fails, and outputs a lighting command to the TCS operating lamp 15 during the TCS operation.

The TCM is a control circuit mainly including a throttle motor drive circuit. The TCM receives a first throttle signal TVO1 from a first throttle sensor 16 and outputs the same to a TCS / ABS-ECU as a throttle 1 actual opening degree DKV. Or input the second throttle signal TVO2 from the second throttle sensor 17 as feedback information to the throttle 2 target opening DKR, or input the throttle 2 target opening DK from the TCS / ABS-ECU.
A motor drive current IM is applied to the throttle motor 18 based on R.

Here, the first throttle valve 19 provided with the first throttle sensor 16 is connected to the accelerator pedal 2.
The second throttle valve 21 provided with the second throttle sensor 17 is provided in the engine intake passage 22 in series with the first throttle valve 19, and is opened / closed by the throttle motor 18. Valve.

The traction control system includes an air flow meter AFM as a peripheral system as shown in FIG.
And an ECCS C / U and an injector, and an engine centralized electronic control system that performs centralized control of fuel injection control, ignition timing control, idle speed correction, etc., is installed. When the ON signal is input, control (select low control) for selecting a smaller valve opening degree of the first throttle signal TVO1 and the second throttle signal TVO2 is performed for transient characteristic correction, and the canister control and the EGR control are performed. Aborted.

Further, as shown in the figure, an automatic transmission control system having an A / TC / U and a shift solenoid and performing a shift control and a lock-up control is mounted as a peripheral system as shown in FIG. , The gear position signal and the shift-up signal are taken into the TCS / ABS-ECU.

Further, as a peripheral system, as shown, a constant speed traveling control system having an ASCD actuator and performing automatic vehicle speed control so as to maintain a set vehicle speed is mounted. When the ON signal of the traction switch signal TCS SW is input, the opening control of the first throttle valve 19 is stopped, and when the OFF signal of the TCS SW is input, the return speed of the first throttle valve 19 is reduced.

FIG. 3 is a hydraulic circuit diagram showing a brake fluid pressure control system commonly used for TCS brake control and ABS brake control for the left and right rear wheels independently.

This brake fluid pressure control system comprises a brake pedal 27, a hydraulic booster 28, a master cylinder 30 having a reservoir 29, wheel cylinders 31, 32,
33, 34, shared hydraulic unit TCS / ABS-HU
, Pump unit PU, and first accumulator unit
AU1, second accumulator unit AU2, front wheel side damping unit FDPU, rear wheel side damping unit RD
With PU.

The TCS / ABS-HU has a first switching valve 35a.
, A second switching valve 35b, and a left front wheel pressure increasing valve 36a.
, A right front wheel pressure increasing valve 36b and a left rear wheel pressure increasing valve 36
c, right rear wheel pressure increasing valve 36d, left front wheel pressure reducing valve 3
7a, a right front wheel pressure reducing valve 37b, a left rear wheel pressure reducing valve 37c, a right rear wheel pressure reducing valve 37c, a front wheel side reservoir 38a, a rear wheel side reservoir 38b, and a front wheel side pump 39.
a, a rear wheel side pump 39b, and a front wheel side damper chamber 40a.
And a rear-wheel-side damper chamber 40b and a pump motor 41.

At the time of normal braking or ABS brake control, both switching valves 35a and 35b are turned off as shown in the figure to introduce the hydraulic pressure from the master cylinder 30.
During the TCS brake control, both switching valves 35a and 35b are turned on to introduce the hydraulic pressure from the second accumulator unit AU2. For example, in the pressure increase mode in the TCS brake control, both control valves 36c, 36d, 37c, and 37d are connected as shown in the figure.
It is set to the OFF position.
In the pressure reduction mode, both control valves 36c, 36d, 37c, 37d are set to the ON position, and the brake fluid from the wheel cylinders 33, 34 is stored in the rear wheel side reservoir 38b. The rotation of the rear wheel side pump 39b returns to the rear wheel side damper chamber 40b.

The first accumulator unit AU1 is used as a hydraulic pressure source for the hydraulic booster 28, and the second accumulator unit AU2 is used as a hydraulic pressure source for TCS brake control. A predetermined accumulator pressure is maintained by the common pump unit PU that sucks in.

The front-wheel-side damping unit FDPU and the rear-wheel-side damping unit RDPU are provided with a common hydraulic unit TCS / AB in order to improve pedal feeling.
The influence of the fluid pressure change in the S-HU on the master cylinder 30 is suppressed.

The operation will be described.

(A) Normal Traction Control Operation FIG. 4 is a control block diagram showing the outline of the traction control performed by the TCS / ABS-ECU. The traction control logic can be roughly classified into the following four types of control.

(1) Calculation of actual slip state Filter processing is performed on the signals of the wheel speed sensors 1, 2, 3, and 4, and based on the wheel speed values after the filter processing, the actual slip state (slip amount, slip amount difference value) is calculated. ) Is calculated.

(2) Calculation of Target Slip State Filter processing is performed on the signal of the lateral acceleration sensor 5 to calculate a target slip state suitable for the running state based on the determination of turning / straight running based on the lateral acceleration and the vehicle speed.

(3) TCS Brake Control The required slip increase / decrease speed (control duty ratio) is calculated by comparing the actual slip state with the target slip state, and is output to the TCS / ABS-HU.

(4) TCS Throttle Control The necessary throttle opening and opening / closing speed are calculated by comparing the actual slip state with the target slip state and output to the TCM.

The characteristics of this control logic are as follows:
In order to secure the limit detectability (steering force, skill sound, etc.) based on the base chassis performance according to each road surface condition that leads to active safety and to obtain active safety, the allowable slip state according to the magnitude of the lateral acceleration, The division of throttle / brake control is decided.

Further, in order to secure stability during shifting and to improve controllability at each gear position, throttle / brake control according to the gear position is performed.

Further, in order to realize smooth acceleration feeling and controllability while suppressing slip hunting, and to realize a responsive engine torque increase / decrease control, an optimum throttle control according to the engine speed is performed.

(B) Traction control action by the optimal gain FIG.
The flowchart showing the flow of the S control processing operation.
Each step will be described.

In step 50, it is determined whether the acceleration slip control is in the non-control state for at least T ₁ (sec). If YES is determined in step 50, the process proceeds to step 51, where the counter is set to 0 (steps 50 and 51 correspond to a control cycle number clearing means).

If the determination in step 50 is NO, the process proceeds to step 52, where it is determined whether or not the vehicle is in an acceleration slip state.

If YES is determined in step 52,
Proceeding to step 53, it is determined whether or not the count = 0. If the count is equal to 0, the normal TCS throttle control and TCS brake control are performed in step 54.

When NO is determined in the step 53, the process proceeds to a step 55, wherein the throttle control gain is made larger than usual, the brake control gain is made smaller than usual, and the TCS
Throttle control and TCS brake control are performed (steps 53, 54 and 55 correspond to acceleration slip control means).

In step 56, as shown in FIG. 7, when a cycle is detected due to a slip peak or the like, the counter value is updated as a counter = counter + 1 for each cycle (corresponding to acceleration slip control cycle number calculation means).

The traction control function during traveling will be described.

If the acceleration slip control is not performed continuously for more than T ₁ (sec) while the vehicle is running without occurrence of the acceleration slip, the process proceeds from step 50 to step 51. The counter which is the number of cycles is cleared to counter = 0.

When an acceleration slip occurs, the process proceeds to step 52 → step 53 → step 54, and the number of control cycles of the acceleration slip is the first cycle, ie, the counter = 0. TCS throttle control and TCS brake control are performed. When the counter is set to 1 in step 56, the flow proceeds from the next control operation to step 52 → step 53 → step 55, and the TCS throttle control is performed with the throttle control gain larger than usual, and TCS brake control is performed with a brake control gain smaller than usual.

Accordingly, as shown in FIG. 6, in the first cycle of the control cycle in which the acceleration slip overshoots, the TCS brake control is operated with a normal control gain, whereby control responsiveness is obtained. In the second and subsequent control cycles in which the acceleration slip converges, the control gain is reduced and the TCS brake control is operated to reduce the brake load and protect the brake. Note that the control cycle 2
After the cycle, the amount of acceleration slip suppression by the brake control becomes small, but by increasing the control gain of the TCS throttle control, the necessary amount of acceleration slip suppression can be maintained.

Here, the control gain of the TCS throttle control is increased by the following method.

(1) The slip amount threshold value is reduced, and the slip allowable state is reduced.

(2) The closing speed of the second throttle valve 21 is increased and the opening speed thereof is reduced.

Here, the control gain of the TCS brake control is reduced by the following method.

(1) Reduce the control duty ratio.

(2) Decrease the brake pressure increase and increase the pressure decrease.

The effect will be described.

(1) In a traction control device for a vehicle in which the acceleration slip is suppressed by using both the TCS throttle control and the TCS brake control, the brake control gain is increased as usual in the first cycle of the control requiring control responsiveness. Since the control gain of the TCS throttle control is increased and the control gain of the TCS brake control is reduced in the second and subsequent cycles to perform acceleration slip control, high control responsiveness and brake protection are achieved during acceleration slip control. And compatibility can be achieved.

(2) Since the control gain of the TCS throttle control is increased in the second and subsequent cycles, the amount of suppression of the acceleration slip by the TCS brake control is reduced in the second and subsequent cycles of the control cycle. , And the total amount of acceleration slip suppression can be maintained by a required amount.

(3) The uncontrolled state of the acceleration slip is T ₁ (s
ec) In the case where the above operation is continued, since the counter indicating the number of control cycles is reset to zero, if a plurality of acceleration slips occur during one run, the above (1), (1) The effect of 2) can be obtained.

Although the embodiment has been described with reference to the drawings, the specific configuration is not limited to this embodiment.

For example, in the embodiment, TC
Although the preferred example of increasing the control gain of the S throttle control has been described, the control gain of the TCS throttle control may be kept normal and only the control gain of the TCS brake control may be reduced in the second and subsequent cycles.

In the second and subsequent cycles, the control gain of the TCS throttle control is gradually increased in each cycle, and the control gain of the TCS brake control is gradually reduced in the above (1) and (2). Most preferred to achieve,
After the second cycle, the control gain of the TCS throttle control may be increased to a predetermined value for each cycle, and the control gain of the TCS brake control may be reduced to a predetermined value to maintain a constant control gain.

[0065]

As described above, according to the first aspect of the present invention, in the traction control apparatus for a vehicle which performs the suppression of the acceleration slip by using both the output control of the internal combustion engine and the brake control, The cycle is the acceleration slip
Each control with control responsiveness that can follow overshoot
Control of internal combustion engine output and brake control
In the second and subsequent cycles , the control gain of the brake control is made relatively smaller than the control gain of the output control of the internal combustion engine to perform the acceleration slip control. Is achieved.

According to the second aspect of the present invention, the control number clearing means for clearing the control number when the acceleration slip control is not performed for a predetermined time is provided. The above effect can be obtained every time an acceleration slip occurs.

[Brief description of the drawings]

FIG. 1 is a diagram corresponding to claims showing a traction control device for a vehicle according to the present invention.

FIG. 2 is an overall view of a braking / drive system control system for a rear wheel drive vehicle to which the vehicle traction control device of the embodiment is applied.

FIG. 3 is a hydraulic circuit diagram showing a brake fluid pressure control system of a braking / drive system control system to which the vehicle traction control device of the embodiment is applied.

FIG. 4 is a block diagram illustrating an outline of traction control in the embodiment.

FIG. 5 is a flowchart showing a flow of a TCS control processing operation using an optimum gain performed by a TCS & ABS electronic control unit of the embodiment device.

FIG. 6 is a time chart of an acceleration slip amount.

FIG. 7 is a diagram illustrating an example of detection of a control cycle based on a slip peak.

[Explanation of symbols]

 a Acceleration slip internal combustion engine output control system b Acceleration slip brake control system c Acceleration slip control cycle number calculation means d Control cycle number clear means e Acceleration slip control means

Claims (2)

(57) [Claims] An acceleration slip internal combustion engine output control system for reducing the output of an internal combustion engine so as to suppress the acceleration slip according to the occurrence of the acceleration slip, and a driving wheel for suppressing the acceleration slip according to the occurrence of the acceleration slip. Slip brake control system for applying braking force to the vehicle, acceleration slip control cycle number calculation means for calculating the number of acceleration slip control cycles, and control of the internal combustion engine output control and brake control in the first cycle of the acceleration slip control cycle Gain of acceleration slip
Control with control responsiveness that can follow overshoot
A vehicle acceleration traction control means for controlling the control gain of the brake control to be relatively smaller than the control gain of the internal combustion engine output control when the number of control cycles is the second cycle or later. Control device. 2. The traction control device for a vehicle according to claim 1, further comprising a control cycle number clearing means for clearing the number of times of control when acceleration slip control is not performed for a predetermined time. apparatus.