JPH0615826B2 - Vehicle acceleration slip control device - Google Patents

Description

The present invention relates to a vehicle acceleration slip control device. More specifically, the present invention relates to a vehicle acceleration slip control device that limits engine torque so that idling of drive wheels does not occur when the vehicle starts and accelerates.

[Prior Art] In front-wheel drive vehicles, the drive wheels easily slip during acceleration,
In addition, uncomfortable body vibration is likely to occur during slip. In addition, it becomes difficult to start in a place where there is little road friction on snow or ice. Especially when a high-performance engine is installed, the driver's accelerator control becomes very difficult. Conventionally, spikes and chains that increase the driving force of high-performance tires and tires on snowy roads, etc. have been used. However, since spikes and chains are often prohibited, slip prevention is difficult.

The inventors of the present invention solve the above problems by
When the difference between the driving wheel speed and the driven wheel speed exceeds a predetermined value, the amount of fuel supplied to the engine and the gear position of the transmission are controlled to reduce the transmission torque from the engine to the driving wheels. Such a vehicle acceleration slip control device has been previously proposed (Japanese Patent Laid-Open No. 58-38347).

[Problems to be Solved by the Invention] In the above invention, since the slip is controlled, the control is actually performed from the time when the slip occurs and the vibration occurs, the response of the control is slow, and the fuel cut There was a point to be improved that a shock occurs when returning.

[Means for Solving the Problem] The present invention has been made as a result of earnest studies by the present inventor focusing on slip torque during vehicle acceleration and vehicle braking. The above problem is solved based on a non-conventional technical idea of suppressing the slip torque to be equal to or less than the slip torque. That is, according to the present invention, as shown in the basic configuration diagram of FIG. 1, the slip determination means M1 for detecting the drive wheel speed and the idle wheel speed and detecting the slip of the drive wheel according to the detected values.
When the vehicle is being braked, when the slip determination means M1 detects a slip of the driving wheels equal to or more than a first predetermined value, the brake pressure is detected, and the detected value is converted into a slip torque during vehicle acceleration. Means M2, and when the slip determination means M1 detects a slip of the drive wheel of a second predetermined value or more during vehicle acceleration, the drive torque of the drive wheel is detected, and the detected value is used as the slip torque during vehicle acceleration. Slip torque detecting means M3 for detecting
And an engine torque control means for storing a newer one of the slip torques converted or detected by the slip torque conversion means M2 or the slip torque detection means M3 in terms of time, and suppressing the engine torque below the slip torque. A vehicle acceleration slip control device characterized by comprising M4 and M4.

[Operation] In the present invention configured as described above, the slip torque conversion means M2 detects the brake pressure when the slip determination means M1 detects the slip of the drive wheel of the first predetermined value or more during vehicle braking. , The detected value is converted into a slip torque during vehicle acceleration. Further, the slip torque detecting means M3 detects the drive torque of the drive wheels when the slip of the drive wheels of the second predetermined value or more is detected during vehicle acceleration, and detects the detected value as the slip torque during vehicle acceleration. .

Then, the engine torque control means M4 stores the newer one of the slip torques converted or detected by the slip torque conversion means M2 or the slip torque detection means M3 in terms of time, and suppresses the engine torque below the slip torque. To do. Therefore, in the present invention, if the slip of the first or second predetermined value or more occurs once, it is possible to grasp the road surface condition based on this and control the engine torque so that the slip does not occur. Become.

Here, the first predetermined value and the second predetermined value may be the same value or different values. For example, a slip amount that maximizes the frictional force between the road surface and the driving wheels can be set as the predetermined value.

Further, the slip conversion means M2 estimates the slip torque from the brake pressure by utilizing the fact that there is a predetermined relationship between the brake pressure during braking and the slip torque during vehicle acceleration. .

[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 that supplies a high voltage to the spark plug, and 7 is a rotation speed sensor of the engine including a gear and an electromagnetic pickup. , 8 is a main throttle valve that is driven according to the depression of the accelerator pedal 9 through a link mechanism to adjust the intake air amount, 11 is an accelerator sensor that detects the opening of the accelerator pedal 9, and 12 is the main throttle valve 8 A DC motor for driving, 13 is a sub-throttle valve provided upstream of the main throttle valve 8 for adjusting the intake air amount, and 14 is for driving the sub-throttle valve. It represents a C motor.

The engine 1 employs a so-called linkless mechanism, and the opening degree control of the throttle valve 8 is performed not by the depression operation of the accelerator pedal 9 but by the DC motor 12. This DC motor 12 is
It is driven based on a signal from an accelerator sensor 11 that detects the amount of depression of the accelerator pedal 9.

Next, 18 is a brake pedal, 19 is a brake pedal 18
2 represents a brake oil pressure sensor that detects a brake oil pressure according to the amount of depression.

On the other hand, reference numerals 20 and 21 denote left and right drive wheels that are rear wheels of the vehicle, and reference numerals 24 and 25 denote a left drive wheel speed sensor and a right drive wheel that detect the rotational speeds of the left drive wheel 20 and the right drive wheel 21, respectively. Represents a speed sensor. 26 and 27 are left and right idler wheels that are rotated as the vehicle runs, and 28 and 29 are left and right wheels, respectively.
It represents a right idle wheel speed sensor.

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

Reference numeral 30 is a power train including a transmission and a differential gear, 31 is an engine output shaft, and 32 and 33 are torque sensors for detecting engine generated torque. Correspondingly, it is composed of an electromagnetic pickup for detecting its rotation. Therefore, the torque is detected by detecting the twist of the output shaft 31 from the deviation of the rotation speed signals of the gears separated by a predetermined distance. The engine generated torque can also be obtained from the detection data obtained by detecting the cylinder pressure with the in-cylinder pressure sensor 34.

Reference numeral 50 designates an electronic control circuit, and in the present embodiment, the electronic control circuit 50 is constructed by using a microcomputer. For further explanation, the configuration of the electronic control circuit 50 is shown as shown in FIG. be able to. In the figure, reference numeral 51 is a central processing unit (CPU) for inputting and calculating data detected by the above-mentioned sensors according to a control program and performing processing for driving and controlling the fuel injection valve 4, the distributor 6, and the DC motors 12, 14. , 52 is a read only memory (ROM) in which data such as the control program and the map is stored, 53
Is a random access memory (R) in which data from each of the above sensors and data necessary for arithmetic control are temporarily read and written.
AM), 54 is the output signal of the waveform shaping circuit and each sensor is C
An input unit provided with a multiplexer or the like for selectively outputting to the PU 51, 55 is a fuel injection valve 4, a distributor 6,
An output unit having a drive circuit for driving the DC motors 12 and 14 according to a control signal from the CPU 51, and 56 is the CPU 5
1, each element such as the ROM 52, the input unit 54, and the output unit 55
A bus line serving as a path for various data is connected to each other, and a power source circuit 57 for supplying power to each of the above units is shown.

Here, the operation of the electronic control circuit 50 will be briefly described. The ROM 52 stores a characteristic program according to the present embodiment, and various types of 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, and the like. Upon receiving the detection signal, the CPU 51 performs a predetermined calculation of the above data and the like using a predetermined memory area of the RAM 53 so that maximum acceleration can be obtained without causing an acceleration slip during vehicle acceleration. Accordingly, a drive signal is output to the DC motor 14 that adjusts the opening degree of the sub-throttle valve 13 to suppress and control the engine output, so that the acceleration slip phenomenon does not occur.

Then, as is well known, the CPU 51 inputs the data of the intake air amount detected by the air flow meter 3 and the engine speed detected by the speed sensor via the input unit 54, and the basic fuel injection amount is calculated from these data. calculate.
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, the optimum ignition timing is calculated based on the engine speed, the intake air amount, etc., using a data map in the ROM 52, for example, and an ignition timing signal is sent to an igniter (not shown) based on the 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 50 configured as described above will be described with reference to the flowchart of the subroutine shown in FIG. This subroutine is executed at predetermined time intervals, and is executed after initialization of various data. First, the outline of the processing will be described. There are five processings as follows. That is, during vehicle braking, when the slip ratio S is equal to the maximum slip ratio Sm, the brake pressure is detected, the reference value TO during vehicle acceleration is estimated from this pressure value, and this value is stored.

When the slip rate S is not equal to Sm during vehicle braking,
A process of controlling the auxiliary throttle valve 13 using the reference value TO to obtain the maximum braking torque.

When the vehicle is accelerating and the slip rate S is smaller than the maximum slip rate SM, a process of controlling the sub throttle valve 13 using the TO during vehicle braking to obtain the maximum drive torque.

A process of calculating and storing a reference value TO from the slip torque TS and the vehicle speed VB when the slip ratio S is equal to a predetermined value SM during vehicle acceleration.

During acceleration, when the slip ratio S is larger than SM, a process for controlling the sub-throttle valve 13 using the standard one value TO to obtain the maximum drive torque.

If the first slip occurs during acceleration rather than during braking, it goes without saying that control is performed using the reference value TO during acceleration.

Next, the above-mentioned processes 1 to 3 will be described in order.

Processing First, at step 101, it is detected whether or not the accelerator opening degree θ detected by the accelerator sensor 11 is positive. Since it is not accelerating here, it is determined to be "NO" and step 1
Jumping to 02, it is determined whether the brake oil pressure P detected by the brake oil pressure sensor 19 is positive. Since braking is being performed here, it is determined to be "YES".
Jumping to 03, the slip ratio S during braking is calculated by the following equation.

S = (VT-VB) / VB (1) Here, VT is the drive wheel speed as an average value of the detection values of the left drive wheel speed sensor 24 and the right drive wheel speed sensor 25, VB.
Is a left idle wheel speed sensor 26 and a right idle wheel speed sensor 27.
Is the vehicle speed as an average value of the detected values of. Further, at this time, the slip ratio S and the generated torque T during braking (braking torque T) obtained from the torque sensors 32 and 33 have a relationship as shown in FIG. 5, and when S is Sm, the braking torque T is The maximum slip torque TS is taken. In the vicinity of this Sm, the road surface friction coefficient becomes maximum, the most acceleration is obtained, and the slip is suppressed well.

Next, at step 104, it is judged if the slip ratio S is equal to the above Sm. That is, it is determined whether the braking torque T is maximum. Here, since S = Sm is established, it is determined to be “YES”. However, since digital processing is actually performed, Sm has a certain minute predetermined range. The routine proceeds to step 105, where the above-mentioned brake hydraulic pressure P is taken in as the brake hydraulic pressure PS, and the routine proceeds to step 106 where the hydraulic pressure PS is converted into a slip torque TS during driving as shown in FIG. As shown in FIG. 6, the hydraulic pressure PS and the slip torque TS have a proportional relationship.

Next, at step 107, the reference value TO is calculated from the relationship between the slip torque TS and the vehicle speed VB. That is, as shown by the dotted line in FIG. 7, one point K is determined from the detected vehicle speed VB and slip torque TS, and passes through this point K,
A straight line of the set inclination-A is drawn, and the value at the intersection with the Y axis is determined as the reference value TO.

Next, at step 108, the reference value TO for this learning control
Is stored in a predetermined area in the RAM 53, and then in step 109, the slip torque TS is calculated from the vehicle speed VB obtained in step 103.
Since the value of VB is the same for 7 and 109, it is the value of the slip torque TS itself detected here.

Next, at step 110, as shown in FIG. 8, the engine speed [r. p. m. ] And the generated torque [Kgm], the throttle opening [%] is calculated. Next, at step 111, the DC motor 14 is driven so that the opening degree of the auxiliary throttle valve 13 becomes the throttle opening degree obtained at step 110, and the process returns to the main routine (not shown).

When it is determined to be "NO" in step 104 during the processing of step (1), steps 109, 110, and 111 are performed, and the control using the TO is performed. That is, at step 109, for example, as shown by the dotted line, the vehicle speed VB
The slip torque TSO corresponding to O is read, and the throttle opening is obtained from the map of FIG. 8 using this.

When θ = 0 and P = 0, the process is terminated and the process returns to the main routine.

Processing When the above-described processing at the time of braking is completed and then the accelerator pedal 9 is depressed, first, since acceleration is in progress, “YES” is determined in step 101.
It is determined that the slip ratio S
Is calculated as in the equation (1). In this case, the relationship between the slip ratio S and the drive torque TS is the same as that shown in FIG. 5, and as shown in FIG. 9, the drive torque T at the slip ratio SM is the maximum slip value. Torque T
It becomes S.

Next, at step 113, it is judged if the slip ratio S is equal to the slip ratio SM, and then at step 114.
To determine whether the slip ratio S is smaller than SM. Here, it is determined as "YES", and step 11
5, the drive torque T is increased according to the elapsed time, and the process proceeds to step 116, where it is determined whether the elapsed time t of this processing is smaller than τ. Here, it is determined to be "YES", and the processes of steps 109, 110 and 111 are performed. That is, the TO obtained in the above-described braking process is used to read TS1 at the present time VB1 from the graph of FIG. 7, and the throttle opening is obtained as shown in FIG.

The slip ratio S also increases as the drive torque T increases in this way, so that it is determined to be “YES” in step 113 performed after the processes of steps 101 and 112, and step 11
7, the driving torque T is taken in as the driving slip torque TS, and the routine proceeds to step 107. Here, as shown in FIG. 7, a TO different from the above-mentioned TO is calculated as a new reference value. And steps 108, 109,
Steps 110 and 111 are performed to control the sub throttle valve 13.

Processing of SM <S when the accelerator pedal 9 is further depressed
Therefore, if "NO" is determined in step 114, the control of the sub throttle valve 13 using the TO obtained in the processing of steps 109, 110, and 111 is executed.

When the predetermined time τ has elapsed in step 116, "N
If it is determined to be “O”, the TO is updated in steps 107 and 108, and then steps 109, 110, and 111 are performed so that the vehicle speed does not drop and the acceleration performance does not deteriorate.

In this process, the target TO becomes large, so the sub-throttle valve 13 is practically fully open.

The left driving wheel speed sensor 24 and the right driving wheel speed sensor 2
5, left idle wheel speed sensor 28, right idle wheel speed sensor 2
9. Steps 103 and 10 of the flowchart of FIG.
4, 112, 113 correspond to the slip determining means, the brake oil pressure sensor 19, the torque sensors 32, 33, and steps 102, 105, 106 in the flowchart of FIG. 4 correspond to the slip torque converting means, and the torque sensor 32,
33, steps 112 and 11 of the flowchart of FIG.
3, 117 corresponds to slip torque detecting means, the auxiliary throttle valve 13 and the DC motor 14, and steps 114, 115, 116, 107, 1 in the flowchart of FIG.
08, 109, 110 and 111 correspond to the engine torque control means.

As described above, according to the present embodiment, the slip torque when a slip occurs during braking or driving is stored,
The opening degree of the throttle valve 13 is determined and the DC motor 14 is driven so that an engine torque larger than the driving force that causes the slip on the road surface is not generated. As a result, regardless of the driver's operation of the accelerator pedal 9, the engine output is controlled so that the idle slip acceleration slip phenomenon of the drive wheels 20, 21 does not occur. Therefore, since the road surface condition is grasped by one slip and the slip is controlled so as not to occur, vibration due to ON / OFF of slip control such as feedback control does not occur, and the responsiveness is fast.

FIG. 10 shows a case where the present invention is applied to a diesel engine 40. In the case of the diesel engine 40, the engine output control is performed by the fuel injection amount and the fuel injection timing. Since they are almost the same, the corresponding parts in FIG. 10 are designated by the same reference numerals as those in FIG. 2, and detailed description thereof is omitted. still,
In FIG. 10, 42 is an air cleaner, 44 is a fuel pump, and 43 is a fuel injection valve. Further, in the flowchart of FIG. 4, steps 101 to 109 are the same as those of the gasoline engine described above, but in step 110, the fuel injection amount and fuel injection timing are calculated instead of the throttle opening, and then in step 111 Instead of controlling the throttle valve, the fuel injection pump 44 will be driven.

The specific embodiment of the present invention has been described above, but the present invention is not limited to this embodiment, and various embodiments are included within the scope of the claims. For example, the present invention can also be applied to a front-wheel drive vehicle. Also, depending on the road friction situation, step 10 in FIG.
The Sm and SM of 4,113 and 114 may be variable.

[Effects of the Invention] The present invention has the following excellent effects. That is, of the slip torques converted or detected by the slip torque conversion means or the slip torque detection means, the one that is newer in time is stored and the engine torque is suppressed below the slip torque. There is an effect that it is possible to grasp the situation and perform control so that slip does not occur, an effect that on / off vibration does not occur due to slip control such as feedback control, and therefore an effect of quick control response.

[Brief description of drawings]

1 is a basic configuration diagram of the present invention, 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,
FIG. 4 is a flowchart showing the control program contents of the electronic control circuit, FIG. 5 is a graph showing the relationship between the slip ratio and the braking torque, and FIG. 6 is a graph showing the relationship between the brake hydraulic pressure during braking and the slip torque during driving. FIG. 7 is a graph showing the relationship between the vehicle speed and the slip torque during driving, FIG. 8 is an explanatory diagram for obtaining the throttle opening from the engine speed and the generated torque, and FIG. 9 is a graph showing the slip ratio and the driving torque. FIG. 10 is a graph showing the relationship, and FIG. 10 is a schematic configuration diagram of another embodiment. 7 ... Revolution sensor 9 ... Accelerator pedal 11 ... Accelerator sensor 12, 14 ... DC motor 13 ... Sub throttle valve 19 ... Brake oil pressure sensor 24 ... Left drive wheel speed sensor 25 ... Right drive wheel speed Sensor 32, 33 ... Torque sensor

Claims (1)

[Claims] 1. A slip determining means for detecting a drive wheel speed and an idle wheel speed, and detecting a slip of a drive wheel in accordance with the detected value, and a slip determining means for determining a value equal to or more than a first predetermined value during vehicle braking. When the slip of the driving wheels is detected, the brake pressure is detected, and the slip torque converting means for converting the detected value into the slip torque during vehicle acceleration, and the slip determining means at the time of vehicle acceleration, the second predetermined value or more is detected. When slip of the driving wheels is detected, the slip torque detecting means for detecting the driving torque of the driving wheels and detecting the detected value as slip torque during vehicle acceleration, and the slip torque converting means or the slip torque detecting means. Of the slip torques converted or detected as a result, the one that is newer in time is stored, and the engine torque is suppressed below that slip torque. Vehicle acceleration slip control device, characterized in that it comprises an engine torque control means, the that.