JPH0833113B2 - Vehicle acceleration slip control device - Google Patents

Description

The present invention relates to a vehicle acceleration slip control device for controlling to prevent excessive slip between a tire of a driving wheel and a road surface during vehicle acceleration, and more particularly to a driving wheel. The present invention relates to a vehicle acceleration slip control device that controls the rotation of a vehicle by the output of an internal combustion engine.

[Prior Art] Conventionally, the drive wheels are prevented from idling during acceleration of the vehicle, and the rotation of the drive wheels is controlled by controlling the rotation of the drive wheels to maximize the frictional force between the tires of the drive wheels and the road surface during vehicle acceleration. A vehicle acceleration slip control device that improves running stability, acceleration, etc. has been invented and proposed.

This type of vehicle acceleration slip control device normally detects the slip ratio of the drive wheels by using the rotational speed of the drive wheels as one parameter, and when the degree of the slip ratio is a predetermined value or more, for example, the ignition timing or the air-fuel ratio. Is controlled to control the output of the internal combustion engine and suppress the rotation of the drive wheels.
Further, as shown in "Vehicle slip control device" of JP-A-61-60331, the opening rate of the throttle or sub-throttle is equivalent to the accelerator pedal depression amount of the driver so that the slip rate becomes an optimum value. Proposals have also been made to control the opening rate below the required opening rate.

[Problems to be Solved by the Invention] Although the vehicle acceleration slip control device that performs the above-described control has an excellent effect of preventing the vehicle from slipping and maximizing the frictional force between the tires of the wheels and the road surface,
The following problems were considered.

That is, the vehicle acceleration slip control device that performs the above control always controls the slip ratio to be around 10% so as to maximize the frictional force between the tires of the wheels and the road surface. Therefore, even if the driver suddenly depresses the accelerator pedal, the vehicle hardly slips, which makes it difficult for the driver to know the road surface condition. In addition, traveling without knowing the road surface condition due to the above-mentioned problems and the like leads to traveling without recognizing a different braking distance depending on the road surface condition, and there is a problem in that it is difficult to make a sudden stop.

Configuration of the Invention [Means for Solving the Problems] The vehicle acceleration slip control device of the present invention is made for the purpose of solving the above problems, and is configured as follows.

The vehicle acceleration slip control device of the present invention has a slip ratio detecting means (M1) for detecting a slip ratio of a drive wheel of a vehicle and a stepping ratio of an accelerator pedal as shown in FIG. The stepping rate detecting means (M2) is related to the case where the detected slip rate is zero,
The target opening degree for obtaining the target opening rate from the stepping rate is reduced by decreasing the increase gradient of the target opening rate of the throttle valve with respect to the increase in the detected stepping rate as the detected slip rate increases. A rate calculating means (M3) and an opening control means (M4) for controlling the output of the wheel drive internal combustion engine by controlling the opening rate of the throttle valve to match the calculated target opening rate. A vehicle acceleration slip control device equipped to prevent excessive slip of the vehicle, wherein the target opening ratio calculation means (M3) has a detected accelerator pedal depression ratio close to a fully opened depression ratio. A vehicle acceleration slip control device comprising: a correction unit (M5) that brings the target opening ratio closer to the relationship between the depression ratio and the target opening ratio at which the slip ratio is zero.

[Operation] In the vehicle acceleration slip control device of the present invention configured as described above, the slip ratio detection means detects the slip ratio of the drive wheels of the vehicle, and the depression ratio detection means detects the depression ratio of the accelerator pedal. To detect. Then, the target opening ratio calculation means obtains the target opening ratio of the throttle valve based on the detected slip ratio of the driving wheels and the depression ratio of the accelerator pedal, and the opening control means determines the opening ratio of the throttle valve. By controlling the rate to match the target opening rate,
Output control of the internal combustion engine for driving the vehicle is performed.

Further, the target opening ratio calculation means determines the increase gradient of the target opening ratio of the throttle valve with respect to the increase of the depression ratio of the accelerator pedal, which is related to the case where the slip ratio of the driving wheels is zero, so that The target opening ratio of the throttle valve is calculated from the depression ratio of the accelerator pedal according to the ascending gradient, but in the present invention, the target opening ratio calculating means is provided with a correcting means. The closer the pedaling rate is to the fully open state pedaling rate, the closer the target opening rate of the throttle valve is to the relationship between the pedaling rate with zero slip rate and the target opening rate.

Therefore, the target opening ratio of the throttle valve set by the target opening ratio calculating means is set to a smaller value as the slip ratio of the driving wheels is higher if the depression ratio of the accelerator pedal is constant. As the accelerator pedal depression rate approaches the fully open state depression rate, the rate of change in the target opening rate with respect to the change in the slip ratio of the drive wheels becomes smaller, and in the region where the accelerator pedal depression rate is in the fully open state, Even if the slip ratio changes, the target opening ratio hardly changes from the value when the slip ratio is zero.

As a result, according to the vehicle acceleration slip control device of the present invention, when the depression ratio of the accelerator pedal is relatively low, the opening ratio of the throttle valve is suppressed along with the increase of the slip ratio of the drive wheels to accelerate the acceleration slip. It is possible to satisfactorily prevent the occurrence of the accelerator pedal, and as the accelerator pedal depression rate approaches the fully open state depression rate, the throttle valve opening rate suppression rate accompanying the increase in the slip ratio of the drive wheels is reduced to reduce the accelerator pedal depression rate. In the region where the pedaling rate is fully open, it is possible to correspond to the opening rate when the slip rate is zero without suppressing the opening rate of the throttle valve.

[Embodiment] Next, a preferred embodiment will be described with reference to the drawings in order to further clarify the configuration of the vehicle acceleration slip control device of the present invention.

FIG. 2 is a schematic configuration diagram showing the periphery of an internal combustion engine and a wheel portion of a vehicle equipped with a vehicle acceleration slip control device according to an embodiment of the present invention.

As shown in the figure, in the intake pipe 2 of the four-cylinder internal combustion engine 1,
A throttle valve 4 for limiting the amount of intake air, a fuel injection valve 6 for injecting fuel into the combustion chamber 5 of the internal combustion engine 1, and the like are mounted upstream of the surge tank 3. The throttle valve 4 is opened and closed by a step motor 7, and the opening rate thereof is detected by a throttle opening sensor 8.
An air filter 9 for purifying intake air and an air flow meter 10 for detecting the amount of intake air are provided upstream of the throttle valve 4.

Further, in the internal combustion engine 1, a water temperature sensor 11 for detecting the cooling water temperature of the internal combustion engine 1 and a high voltage generated by the igniter 12 in synchronization with the rotation of the internal combustion engine 1 are distributed to ignition plugs (not shown) of each cylinder. It also includes a distributor 13, a rotation speed sensor 14 that outputs a pulse signal in accordance with the rotation of the distributor 13, and the like.

The throttle opening sensor 8, the water temperature sensor 11, the rotation speed sensor 14 and the like are connected to an electronic control unit (hereinafter, also simply referred to as an ECU) 20, and the ECU 20 uses the step motor based on the input from each of these sensors. 7 and fuel injection valve 6
And so on.

The ECU 20 is further provided with an accelerator position sensor 2 that outputs a detection signal according to the depression rate of the accelerator pedal 21.
2, connected to the drive wheel speed sensor 24 to detect the average rotation speed of the left and right drive wheels 23L and R of the vehicle, and the driven wheel speed sensors 26L and R that detect the respective rotation speeds of the left and right driven wheels 25L and R, etc. I am letting you.

 Next, the configuration of the ECU 20 will be described.

The ECU 20, as shown in FIG. 3, is a well-known CPU30, ROM31, R
It is configured as a logical operation circuit in which the AM 32 and the like are mainly connected to the external input / output path 33, the external output circuit 34 and the like by a bus 35.

The external input circuit 33 includes the above-mentioned throttle opening sensor.
8, Air flow meter 10, Water temperature sensor 11, Rotation speed sensor 14, Accelerator position sensor 22, Driving wheel speed sensor 24, Left driven wheel speed sensor 26L, Right driven wheel speed sensor 26R, etc. 34 is a fuel injection valve 6
And the step motor 7 and the like are connected.

With the above configuration, the ECU 20 suitably controls the operating state of the internal combustion engine 1 based on the inputs from the various sensors as described above. Here, the ECU 20 will be described with reference to the flowchart of FIG.
The process performed by the throttle valve 4 will be described.

The "throttle valve control routine" shown in FIG.
It is executed periodically (4 ms in this embodiment) by a hard interrupt.

When the processing shifts to this processing, the CPU 30 first calculates the wheel speed Vd based on the value read from the driving wheel speed sensor 24 (step 100). Then, left and right driven wheel speed sensor 2
The vehicle body speed Vs is calculated from the average value of the values read from 6L and R (step 110). After that, each time this processing is executed, the n slip ratios S1 to Sn calculated and stored are shifted one by one, and the latest n-1 slip ratios S1 to Sn- are shifted.
1 is left in the RAM 32 (step 120), and the wheel speed Vd and the vehicle body speed Vd calculated in the above steps 100 and 110.
The slip ratio Sn at this time is calculated from s by the following formula (step 130).

Sn = (Vd-Vs) / Vd The latest n slip rates S1 to Sn are stored in the RAM 32 by the above processing steps 100 to 130.

Then, the maximum slip ratio Smax is calculated from the latest n slip ratios S1 to Sn (step 140).

In step 150, the target throttle opening rate θbase is determined from the map shown in FIG. 5 using the maximum slip rate Smax thus calculated and the accelerator depression rate θa detected by the accelerator position sensor 22. That is, the process of step 150 corresponds to the target opening ratio calculating means, and in the present embodiment, the maximum slip ratio Smax of the latest n slip ratios S1 to Sn and the accelerator depression ratio θ detected this time.
The target throttle opening rate θbase (%) is determined from a. Incidentally, in FIG. 5, slip ratios S = 0, S = 0.1 and S
Although only the respective maps at == 0.2 are described, the slip ratio S = 0 to S = 0.1 and the slip ratio S =
Between 0.1 and S = 0.2, it is assumed that there is a map that supplements the illustrated map. Further, in FIG. 5, the map of the slip rate S = 0.2 shows that the accelerator depression rate θa is 0 to 80.
Up to%, the target throttle opening rate θbase = 0, and when the accelerator depression rate θa exceeds 80%, the target throttle opening rate θbase is the value when the slip rate S = 0 as the accelerator depression amount θa increases. When the accelerator pedal depression rate θa is 100%, the target throttle opening rate θbase is set to be the same as the slip rate S = 0.
Even in other areas of the slip ratio (slip ratio S = 0.1 in the figure), near the maximum accelerator pedal depression rate θa, the target throttle opening degree is increased as the accelerator pedal depression amount θa increases in accordance with the map of the slip rate S = 0.2. The frequency ratio θbase is set to approach the value when the slip ratio S = 0. Therefore, in this embodiment, the slip ratio S = 0.2
The map of the region in which the accelerator depression rate θa: 80 to 10% in (2) functions as the correction means of the present invention.

In the following step 160, the calculated target throttle opening rate θbase (%) is compared with the throttle opening rate θt (%) previously output in this processing. Here, if it is determined that the throttle opening ratio θt ≦ θbase is satisfied, the process proceeds to step 170, and if it is determined that it is not satisfied, the process proceeds to step 180.

In step 170, the throttle opening rate θt to be output this time is set to an opening rate obtained by adding δ (1% in the present embodiment) to the throttle opening rate θt output last time.

On the other hand, in step 180, processing is performed in which the throttle opening rate θt to be output this time is set as the target throttle opening rate θbase calculated in step 150.

After executing the processing of step 170 or 180, the calculated throttle opening rate θt is output to the step motor 7 via the external output circuit 34 (step 190), and this processing ends in “RETURN”.

Next, the operation of the present embodiment in which the above processing is carried out will be described with reference to FIGS. 5 and 6 for the case where the accelerator pedal 21 is depressed from the fully closed state to 40% and then the accelerator pedal is suddenly depressed to about 95%. Explain.

First, the accelerator pedal 21 is fully closed (accelerator depression amount θa
= 0%), the throttle valve 4 is also fully closed (throttle opening θt = 0%) and the slip ratio S becomes zero. Here, when the accelerator pedal 21 is depressed so that the accelerator depression rate θa is 40%, the maximum slip rate Sm up to this time is Sm.
Since ax remains zero (steps 100 to 140), the target throttle opening rate θbase is set to 40% from the map of FIG. 5 (step 150). At this time, since the throttle opening rate θt is still zero, the throttle opening rate θt ≦
θbase is established (step 160), and the throttle opening rate θt output this time is output as δ (step 170).
And 190). As a result, the driving force F of the vehicle is generated and the slip ratio S increases. The maximum slip rate Smax is updated by the increasing slip rate S (steps 100 to 1).
40), the target throttle opening ratio θbase is slightly reduced from 40% (step 150). However, the throttle opening rate θt ≦ θbase is still established and the throttle opening rate θt is 2
It is output as × δ (steps 170 and 190). By repeating this, as shown in FIG. 6, the target throttle opening rate θbase is gradually reduced and the driving force (throttle opening θ
t) F is gradually increased, and the control is balanced at point P1 at which the two become equal (steps 160 to 190).

In the above state, the slip ratio S is controlled to be about 0.1. Here, when the driver depresses the accelerator pedal 21 to set the accelerator depression rate θa to about 95%, the target throttle opening rate θbase is set to about 75% from the map of FIG. 5 (steps 100 to 150). As a result, the target throttle opening rate θbase shifts to the point P2 shown in the figure, but since the target throttle opening rate θbase is high (shown as the target throttle opening rate θ′base in FIG. 6), the throttle opening rate θt Is further increased (steps 160, 170 and 1
90). As a result, the throttle opening rate θt close to the accelerator pedal depression rate θa is output.

Even when the accelerator pedal 21 is close to the fully closed state, the target throttle opening ratio θbase at each slimp ratio S is the slip ratio S as shown in the map of FIG. Since the target throttle opening rate θbase of = 0 is approached, the throttle opening rate θt close to the accelerator depression rate θa is output.

As described above, according to the vehicle acceleration slip control device of the present embodiment described in detail, in the normal depression state of the accelerator pedal 21 (10% ≦ accelerator depression ratio θa ≦ 80%), the slip ratio S of the driving wheels is set to a suitable value. (In this embodiment, it is controlled to be 0 to 0.2) to increase the driving force F. When the accelerator pedal 21 is depressed near the fully open state, the throttle opening rate θt close to the accelerator depression rate θa is set. It has an excellent effect of working to output. This allows
The driver has an excellent effect that he can always know the road surface condition by depressing the accelerator pedal 21, and can expect a further safety effect.

The graph shown in FIG. 7 (a) shows the relationship between the accelerator pedal depression rate θa and the drive wheel slip rate S in each embodiment of the present invention at each road surface condition, that is, at each road surface friction coefficient μ. The graph shown in Fig. 7 (b) shows the road surface friction coefficient μ of a vehicle equipped with a conventional traction control device.
5 is a graph showing the relationship between accelerator depression rate θa and slip rate S in FIG. As can be seen by comparing the respective graphs, the vehicle acceleration slip control device of the present embodiment obtains the slip ratio S according to the road surface condition by depressing the accelerator pedal near the fully open condition.

As described above, one embodiment of the vehicle acceleration slip control device of the present invention has been described in detail, but the vehicle acceleration slip control device of the present invention is not limited to the above embodiment,
The present invention can be implemented in various modes without departing from the scope of the present invention.

Effect of the Invention As described in detail above, according to the vehicle acceleration slip control device of the present invention, when the accelerator pedal depression ratio is relatively low, the opening ratio of the throttle valve increases as the slip ratio of the drive wheels increases. It is possible to prevent acceleration slip from occurring satisfactorily, and as the accelerator pedal depression ratio approaches the fully open depression ratio, the throttle valve opening ratio is suppressed as the drive wheel slip ratio increases. In the region where the ratio is reduced and the accelerator pedal depression rate is in the fully open state, it is possible to correspond to the opening rate when the slip rate is zero without suppressing the opening rate of the throttle valve.

Therefore, according to the present invention, if the accelerator pedal is depressed to a degree close to the fully open state, the drive wheels will slip according to the road surface condition. It is possible to drive the vehicle by accurately grasping the road surface condition, and it is possible to further enhance the safety when the vehicle is running.

Further, in the present invention, when the accelerator pedal depression rate reaches the vicinity of the fully open depression rate, the target opening rate of the throttle valve with respect to the accelerator pedal depression rate is not switched to a value when the slip rate is zero. As the accelerator pedal depression rate approaches the fully open state depression rate, the target opening rate of the throttle valve is gradually approached to the value when the slip rate is zero. Acceleration slip does not suddenly occur at the time of reaching, and the vehicle driver can recognize the road surface condition while safely controlling the vehicle.

[Brief description of drawings]

FIG. 1 is a block diagram illustrating the basic configuration of a vehicle acceleration slip control device of the present invention, and FIG. 2 shows the periphery of an internal combustion engine and wheels of a vehicle equipped with the vehicle acceleration slip control device of one embodiment of the present invention. Schematic diagram, Figure 3 shows the ECU20
FIG. 4 is a flowchart showing the process of the “throttle valve control routine” executed by the ECU 20, and FIG. 5 shows the relationship between the accelerator depression rate θa and the target throttle opening rate θbase at each slip rate S. The graph shown in FIG. 6 is the target throttle opening rate θbase and the driving force F.
Graph showing relationship with (throttle opening ratio θt), 7th
The figure is a graph showing the relationship between the accelerator depression rate θa and the slip rate S at each road surface friction coefficient μ. 1 ... Internal combustion engine 4 ... Throttle valve 7 ... Step motor 8 ... Throttle opening sensor 20 ... Electronic control unit (ECU) 22 ... Accelerator position sensor 24 ... Driving wheel speed sensor 26L, R ... Secondary Wheel speed sensor

Claims (1)

[Claims] 1. A slip ratio detecting means for detecting a slip ratio of a drive wheel of a vehicle, a depression ratio detecting means for detecting a depression ratio of an accelerator pedal, and a relation when the detected slip ratio is zero. The target opening degree for obtaining the target opening rate from the stepping rate is reduced by decreasing the increase gradient of the target opening rate of the throttle valve with respect to the increase in the detected stepping rate as the detected slip rate increases. Excessive slippage of the vehicle, which includes a rate calculation means and an opening degree control means for controlling the output rate of the internal combustion engine for driving the vehicle by controlling the opening rate of the throttle valve to match the calculated target opening rate. In the vehicle acceleration slip control device that works to prevent the above, the target opening ratio calculation means is configured such that the closer the detected accelerator pedal depression ratio is to the fully opened state pedal depression ratio, Vehicle acceleration slip control device characterized by comprising a correction means, which close the relationship between the depression rate and the target opening rate of the slip rate zero ShimegiHirakudo rate.