JPH0194058A - Traction controlling method for vehicle - Google Patents

Abstract

PURPOSE:To aim at improvement in accelerability by altering a throttle closing speed at the time of throttle control starting according to degree of acceleration in the racing of each driving wheel, in a traction controlling method which restrains the racing of driving wheels by means of throttle control. CONSTITUTION:At the initial stage of throttle control, mean acceleration V'G at a while till al reference speed Vr calculated out of wheel speeds VdL, VdR of driving wheels exceeds a threshold speed Vs from speed equal to a pseudo body speed Vv is calculated. According to the degree of this mean acceleration V'G, throttle closing speed in the first throttle closing control is altered. Consequently, such throttle control that is suitable for road conditions can be done, thus improvements in starting and accelerability can be promoted.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a traction control method for a vehicle, and relates to a method for controlling traction of a vehicle, and the present invention relates to a method for controlling traction for a vehicle.
The present invention relates to a traction control method for a vehicle, in which the above-mentioned spin of the drive wheels is suppressed by detecting the engine output and controlling the engine output based on the detection.

(Prior Art) Conventionally, especially when a vehicle runs on a road surface with a low coefficient of friction such as an icy road, snowy road, or muddy road, it is possible to prevent the drive wheels from spinning when the vehicle starts or accelerates. BACKGROUND ART Traction control devices that improve starting performance, acceleration performance, and running stability are known. In such a traction control device, for example, Japanese Patent Application Laid-Open No. 59-68537
As disclosed in the publication, the wheel speed of the driving wheel and the wheel speed of the driven wheel are compared, and when the wheel speed of the former becomes higher than the wheel speed of the rear vehicle by a certain degree, it is determined that the driving wheel is spinning. When the system determines that there is a problem, it reduces the engine throttle opening and lowers the engine output, thereby suppressing the spinning of the drive wheels.

However, in conventional traction control, the throttle is closed at a constant speed when starting throttle control based on the detection of wheel slip, so on road surfaces with a rather high coefficient of friction μ, the throttle may be closed too much during initial control. There was a risk that the acceleration at the time of departure would be insufficient.

(Objective of the Invention) Therefore, an object of the present invention is to provide a traction control method that performs throttle closing control according to road surface conditions and improves acceleration performance.

(Structure of the Invention) The present invention achieves the above object by changing the throttle closing speed at the start of throttle control according to the acceleration of the idle rotation of the drive wheels.

(Effects of the Invention) According to the present invention, it is possible to perform throttle control suitable for road conditions, and it is possible to improve starting and acceleration performance.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows the configuration of a traction control device mainly based on a microcomputer, which is used to implement the present invention.
FIG. 2 is a timing chart explaining the operation. In FIG. 1, 1 is an engine rotation speed sensor, 2 is a sensor that detects the gear position of the transmission,
The outputs of these sensors 1.2 are given to the arithmetic circuit 3,
The vehicle speed EVv corresponding to the engine rotation speed is calculated according to the engine rotation speed and gear position at that time.

On the other hand, the rotational speed of the left and right drive wheels is determined by a rotational speed sensor 4L,
4R, and the wheel speeds VdL and VdR of the drive wheels are respectively calculated by the arithmetic circuit 5.6. These wheel speeds VdL and VdR are given to the arithmetic circuit 7,
The average value of these wheel speeds is the reference speed Vr for starting control.
It is calculated as (= (VdL+VdR)/2). In addition, the rotational speed of the left and right driven wheels is determined by a rotational speed sensor 8L,
8R, and the wheel speeds VnL and VnR of the driven wheels are respectively calculated by the arithmetic circuit 9.10. These wheel speeds VnL and VnR are given to the high select circuit 11, and the wheel speed on the high side of these wheel speeds is calculated as a pseudo vehicle speed VV that is close to the actual vehicle speed. Vv is applied to the threshold setting circuit 12. The threshold setting circuit 12 adds a constant value Vk to the pseudo vehicle speed Vv to create a throttle control threshold speed Vs as shown in FIG. Furthermore, the pseudo vehicle speed Vv, the threshold speed Vs, and the reference speed Vr are given to the calculation circuit 13, and the average of the reference speed Vr from the speed equal to the pseudo vehicle speed VV to the time when the reference speed Vr exceeds the threshold speed Vs. Acceleration■. is calculated. These engine rotation speed equivalent vehicle speed EVv, reference speed Vr, threshold speed Vs, pseudo vehicle body speed Vv, and average acceleration Ω. It becomes an input to the control logic circuit 14. The control I logic circuit 14 also receives the output of a sensor 16 that detects the amount of depression of the accelerator pedal 15.

Based on these input signals, the control logic circuit 14
The throttle drive mechanism 17 is driven to perform throttle control and control the engine output when the vehicle starts or accelerates.

FIG. 3 shows a flowchart of an engine output control routine executed by the control logic circuit 14, which will be described below with reference to FIG.

First, when the vehicle starts, the accelerator pedal is depressed, which increases the vehicle speed EVv equivalent to the engine speed, and the reference speed Vr (drive wheel speed Vd
At time A when the average speed of L and VdR exceeds the threshold speed Vs, a throttle closing command is issued and the throttle speed fixing flag is set down (steps S1 and S2). Next, calculate the average acceleration vG from when the reference speed Vr is equal to the pseudo vehicle speed Vv until it exceeds the threshold speed Vs (
Step S3), if the time required for the reference speed Vr to exceed Vs from Vv is ΔT*. =(Vs-Vv)/Δ
It becomes t. The average acceleration Vc calculated in this way is compared with a predetermined value AC (step S4). and v9≧AC
If so, the throttle closing speed from time A is determined to be a preset first speed v1 (step S5), and V
If a < A C, set vG to another predetermined value BG (B
G<AG), step S6), AG>vG≧
If it is BG, the throttle closing speed from time A is determined to be the preset second speed v2 (step S7, vz
V+)m Furthermore, if V,<BG, the throttle closing speed from time A is determined to be a preset third speed v3 (step S8, v,<vz<V+)++ Next, the engine rotation speed is The equivalent vehicle speed EVv is the threshold speed V
It is determined whether or not the EVV exceeds s and is in an acceleration state (step S9). If this determination is rYEsJ, the throttle speed fixed flag is checked (step S5).
10), if the flag is not set, close the throttle at any of the previously determined throttle closing speeds v1, 8, 2, and reduce the engine output (step 511).
). Next, it is determined whether the accelerator pedal depression amount is smaller than the control value (throttle control termination condition) or not (step 51).
2), if rNOJ, the process returns to step S9; on the other hand, the engine speed equivalent vehicle speed EVv reaches a high peak at time B;
Since the acceleration shifts to deceleration and therefore the determination in step S9 becomes "NO", the throttle speed fixing flag is set (step 513), a throttle open signal is issued at time B, and the throttle is opened at a preset speed ( Step 514), the process returns to step S9 again via step S12.

Engine rotation speed equivalent vehicle speed EVv decelerating from point B
reaches a low peak at time C and then begins to accelerate; however, at this low peak time C, EVv≧Vs and EV
Since v changes to acceleration, the determination in step S9 is rYES.
J, and the process proceeds to step S10, but since the throttle speed fixation flag has already been set, the control proceeds to step S1.
5, and from time point C, the throttle is closed at a preset speed. Then, the process returns to step S9 again via step S12. At the next high peak point of the vehicle speed EVv equivalent to the engine rotation speed, the determination in step S9 becomes rNOJ as at time B, so the throttle is opened in step S14 via step S13, and the process returns to step S9 again via step S12.

Since the engine speed equivalent vehicle speed EVv is below the threshold speed Vs at the next low peak time E,
The determination in step S9 at time E is "NO",
Therefore, the process moves to step 314 via step 313, and the throttle is maintained in the open state. Then, at the time F when the engine speed equivalent vehicle speed EVv exceeds the threshold speed Vs, the determination in step S9 becomes rYEsJ, so the process moves to step S15 via step SIO, closes the throttle at the set speed, and moves to the next high peak point. By opening and closing the throttle alternately in this manner, the vehicle speed EVv corresponding to the engine rotational speed approaches the pseudo vehicle speed Vv, and the desired traction control can be achieved.

As is clear from the above explanation, in this embodiment, the wheel speed VdLSVdR of the driving wheels is set at the initial stage of throttle control.
The average acceleration VG from when the reference speed Vr calculated from is equal to the pseudo vehicle speed VV to when it exceeds the threshold speed Vs set based on the pseudo vehicle speed VV.
is calculated, and the throttle closing speed in the throttle closing control (from the first point A to B) is changed depending on the magnitude of this average acceleration V, so throttle control suitable for the road surface condition is possible. It is possible to improve starting and acceleration performance.

Furthermore, in this embodiment, the wheel speeds VdL and VdR of the driving wheels are
The throttle control based on the comparison between the reference speed Vr calculated and set from the threshold speed Vs set in relation to the actual vehicle speed is limited to the control start point A, and thereafter, the throttle control is performed at the vehicle speed EVv corresponding to the engine rotation speed and the threshold speed Vs. Since the throttle is controlled by comparison with the speed value ■3, the slip in the driving force transmission system can be completely excluded from the control system, and the delay in response of the engine speed to opening and closing of the throttle is taken into account. Since the throttle is opened and closed early in consideration of whether the vehicle speed EVv corresponding to the engine speed is in an acceleration state or a deceleration state, smooth traction control can be achieved.

In addition, in the above-mentioned embodiment, the wheel speed V of the left and right driving wheels is used as the reference speed Vr used for determining the start of traction control.
The average speed of dL and VdR is calculated, but instead of this, the reference speed Vr is the lower wheel speed (low selection) of the wheel speeds VdL and VdR, or the higher wheel speed (high selection). ) may be selected.

[BRIEF DESCRIPTION OF THE DRAWINGS] Fig. 1 is a block diagram showing the configuration of the traction control device used to implement the present invention, Fig. 2 is a timing chart explaining its operation, and Fig. 3 is a flow chart of the throttle control routine. be. 1--Engine rotation speed sensor 2...-Gear position sensor 3--Engine rotation speed equivalent vehicle speed calculation circuit 4L, 4R...-Drive wheel rotation speed sensor 7-Reference speed calculation circuit 8L, 8R--Driven wheel rotation speed sensor 11-High select circuit 12...-Threshold setting circuit 13...Average acceleration calculation circuit 14...Control logic circuit 16--Accelerator pedal depression amount sensor 17-Throttle drive mechanism

Claims (1)

[Scope of Claims] 1. Traction that detects the slippage of the drive wheels that occurs when the vehicle starts or accelerates, and controls the engine throttle based on this detection to suppress the slippage of the drive wheels. A traction control method for a vehicle, characterized in that the acceleration of the idle rotation of the driving wheels is determined, and the throttle closing speed at the time of starting the throttle control is changed depending on the magnitude of the acceleration. 2. In a traction control method that detects the slip of the drive wheels that occurs when the vehicle starts or accelerates, and controls the engine throttle based on this detection to suppress the slip of the drive wheels, the vehicle body speed A throttle control threshold speed having a predetermined relationship with respect to the vehicle speed is set from above, and the wheel speed of the drive wheel is from a speed equal to the vehicle speed until it exceeds the threshold speed. The throttle control is started from the time when the wheel speed of the driving wheels exceeds the threshold value, and the throttle closing speed at the time of starting the throttle control is set according to the magnitude of the average acceleration. A traction control method for a vehicle, characterized in that the traction control method is changed accordingly. 3. The vehicle speed is calculated based on the selected high wheel speeds of the left and right driven wheels, and the threshold speed having a predetermined relationship with the vehicle speed is calculated by increasing the vehicle speed by a certain value. 3. The method according to claim 2, wherein the method is set as a higher speed.