JPS61135945A - Acceleration slipping control device for vehicle - Google Patents

Abstract

PURPOSE:To prevent the occurrence of acceleration slipping by setting an acceleration slipping upper limit torque in accordance with the detected road surface conditions so as to control the engine output for the transmitted torque as detected not to exceed the upper limit. CONSTITUTION:The power transmission torque from the engine to the driven wheels is detected by a transmission torque detecting means M1 such as torque sensor fitted to the propeller shaft. Road surface conditions are detected by a road surface conditions detecting means M2, and the upper limit torque at which the acceleration skidding can occur is set by a torque setting means M3 in accordance with the detected results. The engine output is controlled by controlling the opening of the throttle valve by an engine output control means M4 so that the detected transmission torque may be under the upper limit torque determined as described in the above. In this manner, the engine torque can be maintained at an appropriate level while the optimum air-fuel ratio of retained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an acceleration slip control device for a vehicle. More specifically, the present invention detects the torque actually transmitted in the vehicle's drive system, and controls the throttle valve to close when the torque reaches a level on the verge of causing acceleration slip under each of the -1 conditions. This invention relates to an acceleration slip control device for a vehicle that reliably prevents h11 speed slip by doing the following.

[Prior Art] Conventionally, acceleration slips that occur when a vehicle suddenly accelerates, such as when starting or accelerating, have been prevented by the driver sensing the acceleration slip and controlling the accelerator operation. I was worried. In recent years, research has been conducted on control devices that automatically prevent such acceleration slips, and one such device is an electronically controlled system that controls the amount of fuel injection, ignition timing, etc. according to the vehicle's driving conditions. It has been considered that an engine control device is used to control the engine so that acceleration slip does not occur, that is, the driving wheel torque does not exceed the road friction force. Conventionally, as a device for detecting the acceleration slip, for example, Japanese Patent Application Laid-Open No. 58-38347
As described in the above publication, it has been proposed to detect the wheel speeds of the driving wheels and the driven wheels, and detect acceleration slip when the speed difference between the respective wheel speeds exceeds a predetermined value. This prevents the drive wheels from spinning, resulting in a higher driving force than when the wheels are idling, making it easier to start and climb on low-friction surfaces such as snowy roads, frozen roads, and muddy roads. It becomes easier. Furthermore, since the drive wheels are prevented from spinning, the drive wheels do not lose lateral resistance, and phenomena such as oscillation and turning of the vehicle can be prevented and good slip control can be ensured.

[Problems to be solved by the present invention] However, when detecting acceleration slip in this way,
Problems include the need for multiple sensors to detect the wheel speeds of the driving and driven wheels, and the need to calculate the speed difference each time since acceleration slip is detected from the speed difference between the driving and idle wheels. There is a problem that the detection of acceleration slip is delayed, and furthermore, when a predetermined speed difference occurs between the speeds of each wheel, it is detected that slip has occurred and engine control is performed, so especially for front wheel drive In these vehicles, as a result of suppressing acceleration slip through engine control after acceleration slip actually occurs, the steering force when turning the steering wheel, such as when driving around a curve, or the steering force when turning the steering wheel, or the steering force when turning the steering wheel, etc. This causes problems such as changes in force and a decrease in driving safety.

Also, as an engine control, it is possible to control the fuel injection amount by fuel cut, etc., but in this case, the thrower 1
Since only the amount of fuel injected is reduced without changing the valve opening, irregular combustion and misfires occur due to deviation from the proper air-fuel ratio, resulting in problems with poor drivability such as shocks and surges.

[Means for Solving the Problem] The present invention solves the above problem by opening and closing a throttle valve to suppress the transmitted torque to the torque immediately before acceleration slip of the driving wheels occurs. That is, the present invention, as shown in the basic configuration diagram in FIG. means M2; torque setting means M3 for setting an upper limit torque at which acceleration slip occurs according to the detected road surface condition; The gist of the present invention is an acceleration slip control device for a vehicle, comprising: an engine output control means M4 for controlling engine output;

[Operation] The transmission torque detection means detects the transmission torque used by the engine output control means. The road surface condition detecting means detects the road surface condition used to set the upper limit torque in the torque setting means.

The above-mentioned 1-torque setting means is for setting the torque corresponding to the limit of generation of acceleration slip in accordance with the road surface condition of the road on which the vehicle is traveling. That is, the torque is set high on a road surface with a high friction coefficient, and set low on a road surface with a low friction coefficient.

The engine output control means suppresses the engine output so that the torque transmitted to the drive wheels does not exceed the set torque, thereby preventing acceleration slip. Since the throttle valve is opened and closed as a means of controlling engine output, engine torque can be suppressed while maintaining the optimum air-fuel ratio.

[Example] An embodiment of the present invention will be described below with reference to the drawings.

First, FIG. 2 is a schematic system diagram showing a four-stroke, four-cylinder internal combustion engine (engine) and its peripheral devices in an embodiment in which the present control device is installed.

1 is an engine, 2 is a piston, 3 is a spark plug, 4 is an exhaust manifold, 5 is provided in the exhaust manifold 4,
An oxygen sensor detects the residual oxygen concentration in exhaust gas; 6 is a fuel injection valve provided for each cylinder and injects fuel; 7 is an intake manifold; 8 is provided in the intake manifold 7 and sent to the engine body 1 9 is a water temperature sensor that detects the temperature of the cooling water of the engine 1; 10 is a throttle valve; 12 is a bypass passage that is an air passage that bypasses the throttle valve 10; 13 is a bypass passage 12; An idle speed control valve <IS'CV) which controls the opening area to control the idle rotation speed, 14 an air flow meter which measures the amount of intake air, and 15 an air cleaner which purifies the intake air.

Further, 16 is an igniter that is equipped with an ignition coil and outputs the high voltage necessary for ignition, and 17 is linked to a crankshaft (not shown) and distributes and supplies the high voltage generated by the igniter 16 to the spark plugs 3 of each cylinder. distributor, 1
8 is installed in the distributor 17, and rotates 2 times per revolution of the distributor 17, that is, 2 revolutions of the crankshaft.
A rotation angle sensor that outputs four pulse signals (crank angle signals), 19 a cylinder discrimination sensor that outputs one pulse signal per revolution of the distributor 17, 20 an electronic control circuit, and 21 generated by the engine 1. Each figure represents a torque sensor that is installed on a propeller shaft (not shown) that transmits the generated power to the drive wheels, and outputs a signal corresponding to the transmitted torque.

Further, 22 indicates a passage through which air flows bypassing the throttle valve when the engine is cold, that is, a fast idle bypass passage. Reference numeral 23 indicates an air valve that controls the amount of air passing through the fast idle bypass path 22. The air valve 23 operates to open the fast idle bypass passage 22 in order to secure the engine speed necessary for warm-up operation when the engine is cold.

Further, 24 represents a first road surface condition detector that detects the road surface condition of the road on which the road is being traveled, and in rainy weather, it outputs a wiper activation signal (not shown) to indicate that the road surface is wet. When the vehicle is in a snowy or frozen state, the vehicle is configured to output a signal instructing the driver to operate a switch. Therefore, when no signal is output from the road surface condition detector, it can be determined that the road surface is dry.

25 is an actuator for controlling the throttle valve opening. This embodiment is configured in combination with a known linkless throttle mechanism. That is, a system is usually adopted in which the displacement of the accelerator pedal 27 is converted into an electrical signal by the potentiometer 26, and the actuator 25 opens and closes the throttle valve 10 accordingly, and when the acceleration slip occurrence upper limit torque is reached, the accelerator pedal 27, and the electronic control circuit 2 via the actuator 25.
0 to control the throttle valve 10.

Here, as shown in FIG. 3, the torque sensor 21 is a strain gauge installed in the middle of the propeller shaft 28, which is extendable and whose resistance value is changed by the extension and contraction, so as to convert the rotational displacement into an electrical signal. 29. The torque sensor 21 can be represented by a bridge made up of four variable resistors R, as shown in FIG. 4, for example, and can detect the output voltage vout when a predetermined voltage Vin is input. It is possible to detect yoritotorku. In addition, the strain gauge 29 may also be made of a piezoelectric material, a semiconductor material, or the like that generates a voltage in response to strain.

Next, FIG. 5 shows a block diagram of the electronic control circuit 20.

A central processing unit (CPU) 30 inputs and calculates data output from each sensor according to a control program, and performs processing to control the operation of various devices such as the fuel injection valve 6 and the igniter 16.
1 is a read-only memory (ROM) in which data such as the control program and a map for calculating the ignition advance angle are stored.
, 32 is a random access memory (RAM) from which data input to the electronic control circuit 20 and data required for arithmetic control are temporarily read, and 33 is a random access memory (RAM) from which the data input to the electronic control circuit 20 and data required for arithmetic control are temporarily read out; Backup random access memory (backup R
AM), 34 is an input port (not shown) or provided as necessary - 10 = waveform shaping circuit, multiplexer that selectively outputs the output signal of each sensor to the CPU 30, A/M that converts an analog signal into a digital signal. Input sections each equipped with a D converter, etc. are shown. Reference numeral 35 denotes an input/output section which is provided with an output port in addition to an input port (not shown), and is also provided with a drive circuit etc. for driving the fuel injection valve 6, igniter 16, etc. according to control signals from the CPU 30 as necessary;
Reference numeral 36 represents a path line connecting each element such as the CPU 30 and the SROM 31, the input section 34, and the input/output section 35, and through which each data is sent.

In the engine control device of this embodiment having the above-described configuration, the fuel injection amount, ignition timing, etc. are controlled according to the operating condition based on the detection signals from the above-mentioned sensors. Next, the detection of the road friction state and the associated engine control, which are characteristic processes of this embodiment, will be explained with reference to the flowcharts of two subroutines shown in FIGS. 6 and 7. In this embodiment, opening of the throttle valve is controlled as a means for reducing the driving force of the driving wheels so that acceleration slip does not occur.

First, Fig. 6 shows a predetermined time, for example, 100 [m5ec]
The opening control is executed every time, and detects that the torque transmitted from the engine 1 to the driving wheels exceeds the upper limit torque, and the vehicle is in a state immediately before acceleration slip occurs, and allows the throttle valve opening control described later. Shows control authorization routine. Before starting processing, so-called initialization of the computer is performed, and flags FF and F are set in a main routine (not shown).
θ, Ft are defeated.

In the figure, 101 represents a step of detecting the road surface condition of the road on which the vehicle is traveling based on the signal from the road surface condition detector 24 and detecting the torque V transmitted from the engine 1 to the drive wheels based on the signal from the torque sensor 21. . 102
represents a step of determining whether flag FF indicating whether or not this is the first processing of this subroutine is set. Reference numeral 103 represents a step of setting the upper limit torque VO for acceleration slip generation according to the road surface condition currently detected in step 101 described above. 104 represents a step of setting a flag FF. 105 represents a step of determining whether or not the detected road surface condition has changed from the road surface condition detected during the previous process. 106 represents a step of setting a new upper limit torque ■1 to the upper limit torque vO.

That is, the upper limit torque V1 is determined according to the road surface condition detected in step 101, and the upper limit torque VO is updated. For example, on snowy roads, the upper limit torque V1 is set lower, so the upper limit torque VO is updated to a lower value. 107 represents a step of determining whether the transmitted torque V is greater than or equal to the upper limit torque vO. Here step 10 above
7, it is judged that This means that it has been detected that the wheels are about to start slipping during acceleration. Reference numeral 108 represents a step of calculating the closing amount of the throttle valve 10 to control the opening degree of the throttle valve, which will be described later, in order to prevent acceleration slippage.

In step 108, the throttle valve closing amount is calculated by, for example, using the engine rotational speed NE at this point in time, that is, just before the acceleration slip occurs, as a parameter, and the closing amount Δθ is calculated using a map, etc. as shown in FIG.
All you have to do is set . The graph in FIG. 8 shows that, for example, a map like this can be used to find the closed suspension, and depending on the characteristics of the engine 1, It is sufficient to set it experimentally as shown in (b). 109 represents a step of setting a flag Fθ for permitting throttle valve opening control.

Next, FIG. 7 shows an operation to close the throttle valve 10 when acceleration slip is detected, which is performed as one of a series of engine controls such as fuel injection amount control and ignition timing control that have been conventionally performed. 2 is a flowchart showing a subroutine for controlling engine output.

In the figure □, 201 represents the step of determining whether the flag Fθ is set, and 202 represents the step of determining whether the flag Ft indicating the start of processing is set down. 203 is the current time, that is, the throttle valve 10
This represents the step of reading out time T1 at the start of the control for closing by a free running timer (not shown) and storing it in a predetermined area of the RAM 32. 204 represents a step of setting a flag Ft. 205 is the closing amount Δθ of the throttle valve 10 obtained in step 108 in FIG. This represents the step of controlling the engine output to such an extent that the transmitted torque V does not exceed the upper limit torque VO by performing a reduction correction.

That is, as shown in FIG. 9, the throttle valve opening degree θ is
If Δθ is closed from 1 to θ2, the engine output P decreases from Pl to Pl, and the output of the engine 1 is suppressed. still,
As described above, a linkless mechanism is employed to electronically control the throttle valve 10 regardless of whether the accelerator pedal 27 is depressed, thereby suppressing engine output. 20
6 represents a sub-step of reading the current time T2 from the RAM 32. 207 represents a step of calculating the elapsed time TM after the start of the throttle valve opening control from this time T2 and the time T1 already read in the process of step 203. 208 represents a step of determining whether the elapsed time TM is equal to or greater than 1 at a preset time. It is preferable that 1 is about 0.5 seconds at most. Reference numeral 209 represents a step of determining whether the opening degree S read from the accelerator pedal 27 rubbing signal detected from the potentiometer 26 is 2 or more than a predetermined value. 210 represents the step of defeating the flag Fθ and "t".

In the above configuration, when the process jumps from the main routine (not shown) to the throttle valve opening control permission routine, the road surface condition and torque V are detected in step 101, and the process proceeds to steps 16-102, where the first process is performed. Therefore, it is determined as IN and OJ, and the process proceeds to step 103, where the upper limit torque ■O is set. Next, in step 104, flag FF is set and the process jumps to step 107. Here, since the transmitted torque V is smaller than VO, it is determined to be rNOJ, and the process returns to the main routine.

Next, when the process jumps from the main routine to the throttle valve opening control routine shown in FIG. 7, first, in step 201, since the flag Fθ has been set down, the determination is "NO" and the process returns to the main routine.

Next, when this subroutine is started for the second time or later, after step 101 is executed, step 102 is executed.
Since the flag FF is set, it is judged as rYEsJ and the process jumps to step 105. Here, if the road surface condition does not change, the process directly jumps to step 107, and if the road surface condition changes, in step 106, the process jumps to step 107 where the upper limit torque update process according to the road surface condition obtained in step 101 is executed. , rNOJ is determined in step 107, and the process returns to the main routine.

Next, when the process jumps from the main routine to the throttle valve opening control routine shown in FIG. 7, first in step 201, since the flag Fθ has been set down, rNOJ is determined, and the process returns to the main routine.

We have explained the process before the throttle valve interval control is performed in this way, but here we will explain how the accelerator pedal
7 is depressed and the engine output increases, and as a result, the transmission torque ■ exceeds ■0, step 101 of the above permission routine is executed.
After ~106 is executed, in step 107 rYEsJ
If so, the process proceeds to step 10B, where the throttle valve closing amount Δθ is calculated, and then the process proceeds to step 109, where the throttle valve opening degree control permission flag Fθ is set, and the process returns to the main routine. At this point, throttle valve opening control is started.

That is, when the flag Fθ is set and the throttle valve opening control routine shown in FIG. 7 is started, first, step 20 is started.
1, the determination is ``YES'' and the process proceeds to step 202.
Here, since the flag Ft has been knocked down, it is determined that rYEsJ, and the process proceeds to step 203, where the current time T1 is stored in the RAM 32, and the process proceeds to step 204, where the flag Ft is set. Next, the process proceeds to step 205, where the opening degree θ of the throttle valve is corrected to reduce the engine output P, and the process returns to the main routine.

In the next process, after executing step 201, the process proceeds to step 202. Here, since the flag Ft was set in the previous process, it is determined to be rYEsJ, and the process jumps to step 206, reads the current time T2, and then proceeds to step 202.
In step 07, the elapsed time TM is calculated, and then in step 208
Since this TM is still smaller than 1, the judgment is "NO" and the process jumps to step 209. Here, since the accelerator pedal opening degree S is larger than 1, it is judged as rYEsJ and the process proceeds to step 205, where the aforementioned throttle Correct the valve opening and return to the main routine.

When the process is performed in this way, the engine output P is suppressed, but when the elapsed time TM increases to a certain extent, the transmitted torque is sufficiently suppressed. Therefore, in step 208 of the loop process described above, rYEsJ is determined, and then in step 2
Flag Ft at 10.

Defeat Fθ and return to the main routine. Also, elapsed time TM
Even if the accelerator pedal opening degree S is less than 1, if the accelerator pedal opening S is less than 2, the determination in step 209 is "NO", the process jumps to step 210, and after executing this step, the process returns to the main routine.

In other words, the processes in steps 202 to 204 and steps 206 to 209 are processes for determining the end of the throttle valve opening question, and are performed at a predetermined time after the control to close the throttle valve is started. 1 or when the accelerator pedal opening degree S becomes smaller than 2 to a predetermined value, the transmitted torque is sufficiently suppressed and the occurrence of acceleration slip is completely eliminated, and the throttle valve is closed. It ends.

As described above, in this embodiment, the transmission torque V of the power transmitted from the engine 1 to the drive wheels is detected using the torque sensor 21 provided on the propeller shaft 28, and this transmission torque V is adjusted depending on the road surface condition. Control to close the opening degree of the throttle valve is permitted immediately before the occurrence of acceleration slip that exceeds the upper limit torque 970 for the occurrence of acceleration slip set by the operator. That is, when the vehicle accelerates, the throttle valve 10 is not driven by the operation of the accelerator pedal 27 due to the linkless mechanism, but the actuator 25 is actuated by the command to reduce the throttle valve opening in step 205, and the opening of the throttle valve 10 is adjusted to match the engine rotation. As a result, the engine output is suppressed and the torque transmitted to the drive wheels is reduced. Therefore, the engine output control, which is performed by closing the throttle valve opening, is executed before the acceleration slip occurs, making it possible to prevent the acceleration slip from occurring.

Therefore, for example, in a front-wheel drive vehicle, it is possible to prevent the steering force or the steering force from changing due to acceleration slip when traveling on a curve, resulting in a decrease in driving stability.

In addition, when detecting just before the occurrence of acceleration slip, it is only necessary to detect the transmitted torque and compare it with the upper limit torque set according to the road surface condition, which simplifies the process and prevents detection delays.

Further, in this embodiment, the torque sensor 21 corresponds to the transmission torque detection means, the road surface condition detector 24 corresponds to the road surface condition detection means, and steps 101.102.1 in FIG.
A series of processes 03, 104, 105, and 106 correspond to the torque setting means, and 107 to 109 and 7 in FIG.
A series of processes from steps 201 to 210 in the figure corresponds to engine output control means.

Although specific embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and includes various embodiments within the scope of the claims. That is, in this embodiment, the aforementioned road surface condition detecting means M2 detects -22= wet road surface condition, snowy condition, or frozen condition of the road surface by the wiper operation signal or the driver's own switch operation. Although the detector 24 is used, for example, the road surface condition may be detected by humidity, temperature, etc., and furthermore, a vibration sensor, an inclination sensor, etc. that detect the unevenness and inclination of the road surface may be used. It may be provided.

In this case, the upper limit torque can be set more finely depending on the road surface condition, and more precise acceleration slip control can be executed. Further, as the torque detection means M1,
Although the torque sensor 21 provided on the propeller shaft 28 is used, the torque detection means M1 only needs to be able to detect the torque transmitted from the engine 1 to the drive wheels. Any vehicle power transmission system, such as an axle, can be used as long as the transmitted torque can be detected.

[Effects of the Invention] As detailed above, the acceleration slip control device for a vehicle according to the present invention includes a transmission torque detection means for detecting the torque transmitted from the engine to the drive wheels, and a road surface detection means for detecting the road surface condition of the road on which the vehicle is traveling. condition detecting means, which sets an acceleration slip generation upper limit torque according to the detected road surface condition, and controls engine output by opening and closing a throttle valve so that the detected transmission torque does not exceed the upper limit torque. It is configured. Therefore, unlike conventional acceleration slip prevention devices, which control the engine to control acceleration slip when acceleration slip occurs, engine control can be executed immediately before acceleration slip occurs, and the engine can be controlled immediately before acceleration slip occurs. can be prevented. Therefore, in a front-wheel drive vehicle, it is possible to prevent the steering force or steering force from changing due to acceleration slip when traveling on a curve, resulting in a decrease in driving stability. In addition, when detecting just before the occurrence of acceleration slip, the transmission 1-lux is detected,
Since it is only necessary to compare the torque with the upper limit torque set according to the road surface condition, the process is simplified and the responsiveness of slip detection is improved.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of the present invention, FIGS. 2 to 9 show an embodiment of the present invention, and FIG. 2 shows the engine and A schematic system diagram showing its peripheral devices, Fig. 3 is a configuration diagram of the torque sensor 21, Fig. 4 is its circuit diagram, Fig. 5 is a block diagram showing the electronic control circuit 20, and Fig. 6 is a throttle valve opening control. Flow chart representing authorization routine, No. 7
The figure is a flowchart showing the throttle valve opening control routine, Fig. 8 is a graph showing a map using the engine speed NE as a parameter, which is used to find the throttle valve closing time, and Fig. 9 is a graph showing the throttle valve opening control routine. This is a graph showing the relationship between degree θ and engine output P. 10... Throttle valve 20... Electronic control circuit 21... Torque sensor 24... Road surface condition detector 25... Actuator 26... Potentiometer

Claims (1)

[Scope of Claims] Transmission torque detection means for detecting the transmission torque from the engine to the drive wheels of the drive system; road surface condition detection means for detecting the road surface condition; and occurrence of acceleration slip in response to the detected road surface condition. and an engine output control means that controls engine output by opening and closing a throttle valve so that the detected transmitted torque is equal to or less than the upper limit torque. Acceleration slip control device for vehicles.