JPH068616B2 - 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 returned.

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.

[Means for Solving the Problem] The present invention provides a sub-throttle valve in addition to the main throttle valve and uses the sub-throttle valve to solve the above problems. That is, according to the present invention, as shown in the basic structural diagram of FIG. 1, a drive wheel rotation state detecting means M2 for detecting the rotation state of the drive wheel M1 including the drive wheel speed, and the detected drive wheel M1. Depending on the rotation state, drive wheels M
1 and a control means M4 for suppressing the torque of the engine M3 transmitted to the drive wheels M1 so that the frictional force between the road surface 1 and the road surface becomes large, the control means M4 is linked with the accelerator pedal M5. In addition to the sub throttle valve M8 provided upstream or downstream of the main throttle valve M7 provided in the intake system M6 of the engine M3, and the opening / closing control unit M9 for controlling the opening and closing of the sub throttle valve M8, In the opening control of the opening / closing controls, the sub throttle valve M8 is opened slowly as the difference between the drive wheel speed and the vehicle body speed is large, and the sub throttle valve M8 is opened as the difference becomes smaller. The gist is a vehicle acceleration slip control device characterized by being configured to open M8 quickly.

[Operation] The rotation state detecting means detects whether or not the drive wheels are in a rotation state, that is, a state immediately before the drive wheels slip and become idling. This detection generally uses a driving wheel speed or a driving wheel acceleration. After the state is detected, the opening / closing control unit controls the sub-throttle valve to be closed to control the engine output, and otherwise holds or opens the sub-throttle valve to suppress the decrease in the drive wheel speed. In particular, in the opening control, as the difference between the drive wheel speed and the vehicle body speed is larger, the sub-throttle valve is slowly opened to control the drive wheel speed to be closer to the vehicle body speed. Then, when the difference between the drive wheel speed and the vehicle body speed becomes smaller, the sub-throttle valve is quickly opened to control so as to gradually eliminate the difference between the drive wheel speed and the vehicle body speed. Further, by using the auxiliary throttle valve, the control range of the engine output is widened, and even if there is a failure, the main throttle valve is still operating, so it is safe.

[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 an engine, which 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 an ignition plug. (In FIG. 2, the fuel injection valve 4 and the spark plug 5 are shown only for one cylinder.) 6 is a distributor for supplying a high voltage to the spark plug, and 7 is an engine speed sensor composed of a gear and an electromagnetic pickup. , 8 is a main throttle valve that is driven according to the depression of an accelerator pedal 9 through a link mechanism to adjust the intake air amount, and 10 is a sub-throttle valve that is provided upstream of the main throttle valve 8 and that adjusts the intake air amount. Reference numeral 11 is a DC motor that drives this sub-throttle valve, 12 is a main throttle sensor that detects the throttle valve opening of the main throttle valve 8, and 13 is a sub-throttle. It represents the sub-throttle sensor for detecting the throttle opening of the lube 10. This throttle sensor 12, 1
3 is turned on when the throttle valves 8 and 10 are in the fully closed position.

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 through 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 denotes an electronic control circuit, and it is assumed that the electronic control circuit 30 is configured by using a microcomputer. If the description is advanced, the configuration of the electronic control circuit 30 can be represented as shown in FIG. In the figure, reference numeral 31 denotes a central processing unit (CPU) that inputs and calculates data detected by the above-mentioned sensors in accordance with a control program and performs processing for driving and controlling the DC motor 11.
Reference numeral 2 is a read-only memory (ROM) in which data such as the control program and map is stored, 33 is a random access memory (RAM) in which data required for arithmetic control of data from the respective sensors is temporarily read and written, Reference numeral 34 is an input unit including a waveform shaping circuit and a multiplexer that selectively outputs the output signals of the respective sensors to the CPU 31, 35 is an output unit including a drive circuit that drives the DC motor 11 according to a control signal from the CPU 31, and 36. Is CPU31, R
A bus line 37 connecting each element such as the OM 32 and the input section 34 and the output section 35 to serve as a passage for various data, and 37 each represent a power supply circuit for supplying power to each of the above sections.

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 beginning of the main routine, although the sub-throttle valve 10 is always in the fully opened state after the control is completed. 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 VωF 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, "YE
S ”, that is, less than 100 km / H, so step 10
Go to 5. In this step, the right driving wheel acceleration ωRR
Is greater than the left drive 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 ωR is similarly determined in step 107.
Set L 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 or not. That is, it is determined whether or not the state is immediately before slip. Here, it is determined to be "ON" and the process jumps to step 109. That is, the slip is not generated, and the process of holding the sub throttle valve 10 is performed. In step 109, it is determined whether the driving wheel acceleration ωR is negative. Here, because it is accelerating, "N
It is determined to be “O”, the routine jumps to step 110, holds the sub throttle opening θS, returns to step 102, and performs similar processing.

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 this loop processing is performed.
At 8, it is determined to be "YES" and the process jumps to step 111. Here, the second throttle opening is reduced to θCLOSE. In this embodiment, θCLOSE is zero, that is, the fully closed state. Therefore, as shown in FIG. 5C, 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 is maintained.

When the loop process of the process of (c) is performed, the driving wheel acceleration ωR decreases and it is determined to be “NO” in step 108, and step 1
09, the driving wheel acceleration is positive here, so the routine jumps to step 110, and the auxiliary throttle valve 10 is held in the fully closed state as described above.

By the processing of (d), the driving wheel acceleration is reduced, and step 1
At 09, it is determined to be "YES" and the routine jumps to step 112, and the difference between the drive wheel speed VωR and the idle wheel speed VωF is set as ΔVω. Then in step 113,
Open the throttle valve to the main throttle opening θH.
Here, the opening speed VM of the throttle valve is set by the following equation as shown in FIG.

VM = −KΔVω + B This is because the driving wheel acceleration decreases and VωR =
This is to reduce the shock when VωF is reached.
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 the drive wheel speed differs between small slip and excessive slip, and accordingly, the slope of the straight line is adjusted as shown in FIG. 5C. It is changed according to ΔVω.

Then, at step 114, 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),
Since the processes of (c) and (d) are repeatedly performed and the driving wheel acceleration gradually converges, 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 114, "Y
ES ”, the process returns to 101, the sub-throttle valve 10 is fully opened, and then 102 → 103 → 104 →
The loop process of 105 → 106 → 107 → 108 → 109 → 110 is performed, and the sub throttle valve 10 is held in the fully opened state.

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 sub-throttle valve 10 corresponds to the sub-throttle valve, and a series of processes of the DC motor 11 and the control program of FIG. 4 corresponds to the opening / closing control section.

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

Since the drive wheel acceleration is used for slip detection 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, the control can be performed in consideration of the rise of torque and the delay of the drive system, and accurate control can be performed. Further, according to ΔVω indicating the degree of slip, the opening speed is slowed when ΔVω is large, and the opening speed is fast when ΔVω is small. Therefore, as shown in the descending line from the first peak of VωR in FIG. 5 (a), when a large slip occurs, the sub-throttle valve 10 is slowly opened and the drive wheel speed VωR is increased. Quickly and sufficiently.
Immediately before the drive wheel speed VωR approaches the idle wheel speed VωF and the grip is recovered, as shown in the descending line from the fifth peak of VωR in FIG. In order to reduce the shock when the tire grips the road surface, the sub-throttle valve 10 is opened quickly so that the driving wheel speed VωR decreases gently. As a result, quick and smooth slip control can be realized.

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 output control range is widened while keeping 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.

When the difference between the driving wheel speed and the vehicle body speed is large, the sub-throttle valve is opened slowly, so that the driving wheel speed is quickly reduced to approach the vehicle body speed. Then, when the difference between the drive wheel speed and the vehicle body speed becomes small, the drive wheel speed is gradually decreased.

As a result, a large slip is quickly settled, and when the driving wheel speed approaches the vehicle body speed, the driving wheel speed gradually decreases, and the shock when the tire grips the road surface is reduced. Therefore, there is an excellent effect that both safety and comfort can be achieved at the same time.

[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 the drive wheel speed, drive wheel acceleration, and throttle opening, and FIG. 6 is a graph showing the relationship between the opening speed VM and the difference ΔVω between the drive wheel speed and the idle wheel speed. 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 including a drive wheel speed, and a frictional force between the drive wheel and a road surface is large according to the detected rotation state of the drive wheel. In the acceleration slip control device for a vehicle, the control means for suppressing the engine torque transmitted to the drive wheels so that the control means works in conjunction with the accelerator pedal, upstream of the main throttle valve provided in the intake system of the engine or A sub-throttle valve provided downstream and an opening / closing control unit that controls opening and closing of the sub-throttle valve are provided. Particularly, in the opening control of the opening / closing control, the drive wheel speed and the vehicle body speed are combined. The larger the difference, the more slowly the sub-throttle valve is opened, and the smaller the difference, the faster the sub-throttle valve is opened. A vehicle acceleration slip control device characterized by: