JPH0654095B2 - Vehicle acceleration slip controller - Google Patents

Description

The present invention relates to an acceleration slip control device for a vehicle. More specifically, the present invention relates to an acceleration slip control device for a vehicle that detects a rotation state of drive wheels and controls a sub-throttle valve in accordance with the rotation state to suppress engine output and perform optimum acceleration slip control. Is.

[Prior Art] Starting and running on a road surface having a low coefficient of friction such as on ice or a snowy road is very dangerous because the vehicle may slip to the back or the vehicle spins due to slip of driving wheels. Therefore, in order to increase the friction coefficient between the tire and the road surface, spike tires, chains, etc. are conventionally installed.

A traction control system that suppresses the slip of the drive wheels is also considered, and the slip ratio [(vehicle speed-drive wheel speed) / drive wheel speed] is set to -0.1 to -0 so that the road surface friction coefficient is maximized. The engine output and the like are controlled so as to be controlled in the vicinity of 0.2. The engine output control is as follows. That is, ignition advance control, fuel cut, fuel cut for each cylinder, linkless throttle valve system, that is, the throttle valve is controlled when slip occurs.

As a result, the engine output is suppressed, and as a result, acceleration slip is suppressed and safe driving is ensured.

[Problems to be Solved by the Present Invention] However, the above-mentioned related art has the following problems. That is to say, because of the narrow torque control range, there is no effect on a low friction coefficient road surface.

For, a shock occurs when the fuel cut is restored.

With regard to (3), although the shock at the time of fuel recovery is small, the vibration at the time of reducing the cylinder becomes a problem.

There was a problem with reliability because of the linkless mechanism.

Further, if the throttle valve is controlled to be fully closed when a slip occurs, the following problems occur. That is, when the control is operated from the start state, the slip of the driving wheels decreases as the control progresses. In addition, the vehicle speed will also increase. Then, as the vehicle speed increases, the vehicle may enter an uncomfortable region in terms of driving feeling as follows.

As the slip of the drive wheels decreases, the amount of reduction in engine torque required to suppress the slip also decreases. Therefore, when the throttle valve is always fully closed regardless of the vehicle speed when a slip occurs, the slip is eliminated in a shorter time as the slip decreases. When the slip is eliminated, the throttle valve closing control is executed and the slip occurs again. As a result, the frequency of the throttle valve opening / closing control becomes high.

Further, as the vehicle speed increases, the running resistance received by the vehicle body also increases. Therefore, the higher the vehicle speed, the larger the engine torque required to maintain the vehicle speed, and the larger the engine torque decrease amount when the throttle valve is fully closed. Then, the driving wheel acceleration (driving wheel deceleration) for suppressing the slip increases, and the shock applied to the vehicle also increases when the driving wheel speed matches the vehicle speed.

Therefore, the present invention has been made for the purpose of solving the above-mentioned problems relating to the controls (1) to (3) and providing an acceleration slip control device for a vehicle that provides a comfortable driving feeling.

[Means for Solving the Problem] The present invention, which has been made to achieve the above object, has a drive wheel rotation state detecting means for detecting a rotation state of a drive wheel, as illustrated in FIG. An acceleration slip control device for a vehicle, comprising: a control unit that suppresses an engine torque transmitted to the drive wheels so that a frictional force between the drive wheels and a road surface increases according to a rotation state of the drive wheels. A vehicle speed detecting means for detecting the vehicle speed, a sub-throttle valve provided upstream or downstream of the main throttle valve provided in the intake system of the engine, which is interlocked with the accelerator pedal, and a large value is set as the detected vehicle speed increases. A closing control opening calculating means for calculating the closing control opening of the sub-throttle valve, and an opening / closing control section for controlling the opening and closing of the sub-throttle valve. Open or out of the closed control, closing control is summarized as acceleration slip control device for a vehicle, characterized in that it is made as a target value a close adjournment level calculated above.

[Operation] In the present invention having such a configuration, the control means controls the opening / closing of the sub-throttle valve in accordance with the rotation state of the drive wheel detected by the drive wheel rotation state detection means, thereby causing friction between the drive wheel and the road surface. Suppress the engine torque to increase the force.
Here, by using the sub-throttle valve for controlling the engine torque, the control range of the engine output is widened, and even if the sub-throttle valve fails, the main throttle valve is still operating and safety is ensured. .

Further, in the present invention, the target value for closing control of the sub-throttle valve (close control opening degree) is set to be larger as the vehicle speed increases. Here, when the control is performed from the start state, the drive wheel slip decreases as the vehicle speed increases, that is, as the control progresses, and the engine torque decrease amount necessary to suppress the slip decreases. In the present invention, the decrease in the engine torque due to the closing control becomes smaller as the vehicle speed increases, so that the frequency of the sub-throttle valve opening / closing control changes smoothly and the convergence time of the drive wheel slip becomes slow.

Furthermore, as the vehicle speed increases, the running resistance increases, and the engine torque required to maintain the vehicle speed also increases. In the present invention, as described above, as the vehicle speed increases, the decrease amount of the engine torque due to the closing control decreases,
An increase in drive wheel acceleration (drive wheel deceleration) at the time of suppressing slip is prevented, and in turn, an increase in shock applied to the vehicle when the drive wheel speed matches the vehicle speed is prevented.

[Examples] The present invention will be described below with reference to the drawings with reference to Examples.

FIG. 2 is a schematic configuration diagram of one embodiment, in which the present invention is applied to a front engine / rear drive (FR type) vehicle equipped with a gasoline engine. In the figure, 1 is a 4-cylinder fuel injection engine, 2 is an intake pipe, 3
Is an air flow meter, 4 is a fuel injection valve provided for each cylinder that injects fuel into intake air, and 5 is a spark plug (secondary
In the figure, the fuel injection valve 4 and the spark plug 5 are shown only for one cylinder. ), 6 is a distributor that supplies a high voltage to the spark plug, 7 is an engine speed sensor consisting of a gear and an electromagnetic pickup, and 8 is driven by a accelerator pedal 9 via a link mechanism to adjust the intake air amount. Main throttle valve 10 is this main throttle valve 8
Of the auxiliary throttle valve for adjusting the intake amount, 11 is a DC motor for driving the auxiliary throttle valve, 12 is a main throttle sensor for detecting the throttle valve opening of the main throttle valve 8, and 13 is an auxiliary throttle valve 10. The sub-throttle sensor for detecting the throttle opening of The throttle sensors 12 and 13 are turned on when the throttle valves 8 and 10 are in the fully closed position, respectively.

On the other hand, 20 and 21 are left and right drive wheels, which are the rear wheels of the automobile, respectively, and the power of the engine 1 is the transmission 2
2, transmitted via the propeller shaft 23 and the like. Two
Reference numerals 4 and 25 denote a left drive wheel speed sensor and a right drive wheel speed sensor for detecting the rotational speeds of the left drive wheel 20 and the right drive wheel 21, respectively. Reference numerals 26 and 27 denote left and right idler wheels that are rotated as the vehicle runs, and reference numerals 28 and 29 denote left and right idler wheel speed sensors, respectively.

The sensors 24, 25, 28 and 29 are composed of gears and electromagnetic pickups.

Reference numeral 30 indicates an electronic control circuit.

Here, assuming that the electronic control circuit 30 is configured by using a microcomputer, the electronic control circuit 3
The configuration of 0 can be represented as shown in FIG. In the figure, reference numeral 31 is a DC motor 11 for inputting and calculating data detected by the above-mentioned sensors according to a control program.
A central processing unit (CPU) 32 for performing processing for driving and controlling a read-only memory (R) in which data such as the control program and maps is stored.
OM), 33 is a random access memory (RAM) in which data from each sensor and data necessary for arithmetic control are temporarily read and written, and 34 is a waveform shaping circuit or selectively outputs output signals of each sensor to the CPU 31. An input unit equipped with a multiplexer or the like for controlling the DC motor 11 to the CPU 3
1, an output unit provided with a drive circuit driven in accordance with a control signal from 1, a bus line serving as a passage for various data by connecting each element such as the CPU 31 and the ROM 32, the input unit 34, and the output unit 35, and 37 each unit described above. Power supply circuits for supplying power to the respective.

Next, the operation of the electronic control circuit 30 will be briefly described. Receiving various detection signals from the left drive wheel speed sensor 24, the right drive wheel speed sensor 25, the left idle wheel speed sensor 28, the right idle wheel speed sensor 29, etc., maximum acceleration is achieved without acceleration slippage during vehicle acceleration. In order to obtain the slip control, a slip control is executed to output a drive signal to the DC motor 11 that adjusts the opening of the sub-throttle valve 10 to suppress the engine output.

Further, as is well known, the CPU 31 inputs the data of the intake air amount detected by the air flow meter 3 and the engine speed detected by a rotation angle sensor (not shown) through the input unit 34, and based on these data, the basic fuel Calculate the injection amount. Then, this basic fuel injection amount is corrected by the residual oxygen concentration in the exhaust gas detected by an oxygen sensor (not shown), and the actual fuel injection amount is calculated. Then, the fuel injection valve 4 is controlled on the basis of this actual fuel injection amount, and fuel injection, that is, fuel supply suitable for the operating state of the engine is performed.

Similarly, based on the engine speed, the intake air amount, etc., the optimum ignition timing is calculated using, for example, the data map in the ROM 32, and the ignition timing signal is sent to an igniter (not shown) based on the calculated optimum ignition timing. Ignition timing control is performed according to the operating state of the engine such as the number.

Next, the acceleration slip control executed by the electronic control circuit 30 configured as described above will be described with reference to the flowchart of the main routine shown in FIG. First, the outline of the processing will be described. The processing is roughly divided into the following three processing. That is, this is a process for holding the opening of the sub-throttle valve 10 as indicated by an arrow in the figure, that is, a process that is performed when the driving wheel acceleration is smaller than a positive predetermined value.

This is a process for controlling the closing of the sub-throttle valve 10, that is, a process performed when the driving wheel acceleration is larger than a positive predetermined value.
This suppresses the engine output.

This is a process for controlling the opening of the sub-throttle valve 10, that is, a process that is performed when the driving wheel acceleration is negative to increase the engine output and slow down the driving wheel speed.

These processes are performed by determining the driving wheel acceleration, but since the driving wheel acceleration repeats positive and negative, →→
→ processing is executed in one cycle. Next, these processes will be described in detail with reference to FIGS.

Process of (a) First, in step 101, the DC motor 11 is driven so that the sub throttle valve 10 is fully opened. This is a process for ensuring that the sub-throttle valve 10 is fully opened at the end of control, but is surely fully opened at the start of the main routine. Next, at step 102, it is judged if the main throttle sensor 13 is on, that is, if the engine is idling or accelerating. If "YES", that is, if idling is determined, step 101
Return to. Since the process is accelerating here, it is determined to be "NO" and the routine proceeds to step 103, where the average value VεF of the left and right idle wheel speeds, the idle wheel acceleration ωF, the left drive wheel speed VωRL, and the right drive wheel speed VωRR. , Left drive wheel acceleration ω
RL, right drive wheel acceleration ωRR, main throttle opening θ
H and the sub throttle opening θS are calculated respectively.

Next, at step 104, the idle wheel speed VωF (considered as the vehicle speed) is the set control end vehicle speed VMAX, for example, 1
It is determined whether it is smaller than 00 Km / H. If "NO" is determined, the process returns to step 101. Here, "Y
ES ”, that is, less than 100 Km / H, the process proceeds to step 105. In this step, the right drive wheel acceleration ω
It is determined whether RR is larger than the left driving wheel acceleration ωRL. That is, it is determined which of the left and right drive wheel accelerations has the larger slip. If "YES" is determined, the right drive wheel acceleration ωRR is set as the drive wheel acceleration ωR in step 106. If “NO” is determined, the left driving wheel acceleration ω is similarly determined in step 107.
Set RL as ωR. In this way, the drive wheel with large slip is selected, and slip control is performed by this.

Next, at step 108, it is judged if the driving wheel acceleration ωR is larger than a predetermined value A. That is, it is determined whether or not the state is immediately before slip. Here, it is determined to be "NO" and the process jumps to step 109. That is, no slip has occurred, and processing for holding or opening the sub-throttle valve 10 is performed. In step 109, it is determined whether the driving wheel acceleration ωR is negative. Here, since the vehicle is accelerating, it is determined to be "NO", the routine jumps to step 110, holds the auxiliary throttle opening θS, returns to step 102, and similar processing is performed.

Process of (b) In such a loop process, the driving wheel acceleration increases as shown in FIG. Therefore, since the driving wheel acceleration ωR exceeds A, step 10 of the above loop processing is performed.
At 8, it is determined to be "YES" this time, and the process jumps to step 111. Here, as shown in FIG. 6, the opening θCLOSE is K2 · VωF when the sub-throttle valve 13 is closed.
To set. However, K2 is a constant. This θCLOS
The reason for changing the E value according to the idle wheel speed VωF as the vehicle speed is mainly to smooth the convergence of the drive wheel speed VωR. More specifically, for example, as shown in FIG. 5 (a), when the control starts from the starting state, the slip of the rear wheels indicates the slip amount as the control progresses ΔVω (ΔVω = VωR−, as will be described later). VωF) will decrease. The vehicle speed will also increase. In this case, if the auxiliary throttle valve 10 is controlled to a constant value, for example, fully closed, the control frequency of VωR becomes higher as the vehicle speed becomes higher, which may result in an uncomfortable region in terms of driving feeling.
Therefore, the value of θCLOSE is controlled by the vehicle speed to avoid the above phenomenon and obtain a smooth running state.

Next, the routine proceeds to step 112, where the sub-throttle opening is reduced to θCLOSE. Therefore, Fig. 5 (C)
As shown in, the sub-throttle valve 10 is driven from the fully open state to the fully closed state by the DC motor 11, and the fully closed state (that is, the state of θS = θCLOSE) is maintained.

Next, at step 113, it is judged if the drive wheel acceleration ωR is larger than the maximum value ωRMAX of the drive wheel acceleration up to the previous time. Here, since the driving wheel acceleration ωR is not increasing to the maximum value and is increasing, it is determined to be “YES” and step 1
14, the drive wheel acceleration ωR in step 113 is set as the maximum value ωRMAX of the drive wheel acceleration in this case, and if “NO” is determined, step 11 is executed.
Jump 4 and return to step 102. That is, steps 113 and 114 are the maximum value ω of the driving wheel acceleration ωR.
This is a process for detecting RMAX.

When the loop process of the process (c) is performed, the driving wheel acceleration ωR decreases after reaching the maximum value of the driving wheel acceleration and becomes smaller than the predetermined value A, so that it is determined as “NO” in step 108,
The routine jumps to step 109, where the driving wheel acceleration is positive, so the routine jumps to step 110 and the sub-throttle valve 10 is held in the fully closed state as described above.

The drive wheel acceleration ωR is reduced by the process of (d), this time it is determined to be “YES” in step 109 and the routine jumps to step 115, where the drive wheel speed VωR and the idle wheel speed V
The difference from ωF is set as ΔVω. Then step 1
16, the opening speed VM of the sub-throttle valve 10 is 7th.
It is set by the following equation as shown in the figure.

VM = −K ΔVω · ωRMAX + B where ΔVω is the value obtained in step 115, ωR
MAX is a value obtained in step 114, and K and B are constants.

This is because the driving wheel acceleration decreases and VωR =
This is to reduce the shock when it reaches VωF.
This shock occurs because the road surface friction coefficient increases when the tire grips the road surface and the driving force increases. Further, the reason why VM is changed by ΔVω is that the degree of decrease in driving wheel speed differs between small slip and excessive slip, and accordingly, as shown in FIG. The inclination is changed by ΔVω.

Further, the reason why it is also changed by ωRMAX corresponds to the time difference TH until the driving wheel acceleration ωR becomes equal to VωF by ΔVω on the same high friction coefficient road (high μ road) as shown in FIG. However, there is a further time difference TL between the high μ road and the low friction coefficient road (low μ road). Therefore, ωRMA having a correlation with the road surface friction coefficient
The time difference TL is eliminated by detecting X. That is, as shown in FIG. 7, ωRMAX
When is small, the opening speed VM is increased, and conversely, when ωRMAX is large such as on a low μ road, the opening speed VM is controlled to be slow to smooth the slip reduction and eliminate the shock. Further, the reason why the sub-throttle valve 10 starts to open at the time of ωR <0 is to consider the rise of the engine torque (responsiveness) and the delay of the drive system, especially the delay in the automatic transmission, in order to make it early.

Next, at step 117, the sub-throttle valve 10 is opened at the opening speed VM to the opening degree θH value of the main throttle valve. In the following step 118, since the opening of the sub-throttle valve 10 has been completed, the maximum value of the driving wheel acceleration is set to zero and initialized.

Then, at step 119, the elapsed time TS during which the opening degree θS of the throttle valve 10 is kept at θH is the predetermined value TO.
It is determined whether or not it is larger than P. Since it is determined to be "NO", the process returns to step 102 and the loop process is performed.

In this way, when the sub-throttle valve 10 is gradually opened and the engine output rises, the driving wheel acceleration rises, and it is judged "NO" in step 109 and the first processing starts again. Thus (a), (b), (c
) And (d) are repeatedly performed and the driving wheel acceleration gradually converges, so that the driving wheel speed also converges.

Therefore, the driving wheel acceleration does not exceed the predetermined level A, and it is determined that the driving wheel acceleration is suppressed, and the processing is repeated. Therefore, in step 119, "Y
ES ”, the process returns to 101, the sub-throttle valve 10 is fully opened, and then 102 → 103 → 104 →
A loop process of 105 → 106 → 107 → 108 → 109 → 110 is performed, and the sub throttle valve 10 is held in the fully opened state as shown in FIG.

Further, in this embodiment, the left and right drive wheel speed sensors 24, 2
5 corresponds to the drive wheel rotation state detecting means, and the electronic control circuit 3
0 corresponds to the control means, the left idle wheel speed sensor 28 and the right idle wheel speed sensor 29 correspond to the vehicle speed detecting means, and the DC motor 11 and step 110 in the control program of FIG.
Reference numerals 112 and 117 correspond to the opening / closing control unit and the processing thereof, and step 111 in the control program of FIG. 4 corresponds to the processing of the closing control opening calculation means.

As described above, according to the present embodiment, the engine intake air amount can be controlled by using the auxiliary throttle valve 10 for engine output control, so that the engine output control range can be widened while keeping the air-fuel ratio at the optimum value. . Even if the sub-throttle valve 10 fails, the main throttle valve 8 can operate normally.

Since the drive wheel acceleration is used to detect the slip of the drive wheel, the detection can be speeded up. Further, since the opening control of the sub-throttle valve 10 is performed from the position where the driving wheel acceleration is negative, it is possible to perform accurate control in consideration of the rise of torque and the delay of the drive system. Furthermore, it indicates the degree of slip △
Since the opening speed VM is changed depending on Vω, the shock when the driving wheel speed VωR becomes slower and the driving wheel speed VωR and the idle wheel speed VωF become equal, that is, when the tire grips the road surface is reduced. it can.

Since the opening speed VM is slowed down by the maximum value ωRMAX of the drive wheel acceleration, the drive wheel speed VωR decreases more slowly on the low μ road, and the shock can be reduced.

Therefore, good slip control can be realized on both the high μ road and the low μ road.

Further, in the processing of (1), the opening degree θCLOSE of the sub-throttle valve 10 is increased as the vehicle speed is increased.
The control frequency of the drive wheel speed VωR changes smoothly and the convergence time becomes slow. Therefore, the traveling becomes smooth, the traveling feeling becomes good, and the durability of the vehicle improves.

Although the specific embodiments of the present invention have been described above, the present invention is not limited to such embodiments, and various embodiments are included within the scope of the claims. Therefore, for example, the present invention can be applied to a front engine front drive (FF system).

[Effects of the Invention] The present invention has the following excellent effects. That is, since the auxiliary throttle valve is provided upstream or downstream of the main throttle valve, the engine intake air amount can be controlled, so that the engine output control range can be widened while maintaining the air-fuel ratio at the optimum value.

Even if the sub-throttle valve fails, the main throttle valve can operate normally, so that the vehicle can travel safely.

Since the target value for the sub-throttle valve closing control is set larger as the vehicle speed increases, the frequency of the sub-throttle valve opening / closing control changes smoothly and the convergence time of the drive wheel slip becomes slower. It is possible to prevent the shock applied to the vehicle from increasing with the vehicle speed when the drive wheel speed matches the vehicle speed. Therefore, according to the present invention, a comfortable traveling feeling can be obtained over all vehicle speeds. Therefore, the traveling becomes smooth, the traveling feeling becomes good, and the durability of the vehicle improves.

[Brief description of drawings]

FIG. 1 is a basic configuration diagram, FIG. 2 is a schematic configuration diagram of an embodiment of the present invention, FIG. 3 is a block diagram of an electronic control circuit, and FIG. 4 is a flowchart showing a control program content of the electronic control circuit. FIG. 5 is a timing chart of driving wheel speed, driving wheel acceleration, and throttle opening, FIG. 6 is a graph showing the relationship between opening θCLOSE and idle wheel speed VωF during closing control, and FIG. 7 is opening speed VM. And the difference ΔVω between the driving wheel speed and the idle wheel speed and the product Δω · VωRMAX of the maximum value ωRMAX of the driving wheel acceleration, and FIG. 8 is a driving wheel speed on a high μ road and a low μ road. And the timing chart of the driving wheel acceleration are shown respectively. 8 ... Main throttle valve 9 ... Accelerator pedal 10 ... Sub throttle valve 11 ... DC motor 12 ... Main throttle sensor 13 ... Sub throttle sensor 24 ... Left drive wheel speed sensor 25 ... Right drive wheel speed sensor 30 ... Electronic control circuit

Claims (1)

[Claims] 1. A drive wheel rotation state detecting means for detecting a rotation state of a drive wheel, and transmission to the drive wheel such that a frictional force between the drive wheel and a road surface becomes large in accordance with the detected rotation state of the drive wheel. In a vehicle acceleration slip control device including control means for suppressing engine torque, said control means is a vehicle speed detection means for detecting vehicle speed and a main throttle valve provided in an intake system of the engine, which is interlocked with an accelerator pedal. A sub-throttle valve provided upstream or downstream of the sub-throttle valve, a close-control opening degree calculating means for calculating a close-control opening degree of the sub-throttle valve which is set to be large as the detected vehicle speed increases, An opening / closing control unit for performing opening and closing control is provided, and among the opening or closing controls, the closing control is performed by using the calculated closing control opening as a target value. Acceleration slip control device for a vehicle according to.