JPH01197161A - Slip controller for vehicle - Google Patents

Abstract

PURPOSE:To surely enable starting under self control in a device where slipping of drive wheels against a road surface is restrained by controlling torque to the drive wheel by prohibiting slip control upon starting. CONSTITUTION:Generation of torque is controlled by controlling the opening of a throttle valve 13 arranged at an intake path 12 of an engine 6. The throttle valve 13 is controlled at its opening by controlling operation of a throttle actuator 14 controlled by a control unit U. Excessive slipping on a road surface is prevented by controlling generation of torque, i.e. torque to drive wheels. In such a device, when starting of a vehicle is detected by means of detection signals from a vehicle speed sensor 64, acceleration opening sensor 67 and the like, the aforesaid slip control is prohibited, and starting is performed by driver's self control.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a slip control device for a vehicle.

(Prior art) As seen in Japanese Unexamined Patent Publication No. 57-22948, there is a system in the city that prevents the drive wheels from slipping excessively on the road surface by controlling the torque applied to the drive wheels.
There are known devices designed to do this. In this type of vehicle, even if the driver depresses the accelerator pedal too much, the over-speed of the drive wheels is suppressed, so it is safe even on low, slippery roads such as snowy roads, and it also provides optimal driving performance. It has the advantage of providing sexual Y-taxis.

However, the flip side of this is that there is a slip control device, which gives a psychological sense of security, which tends to make the accelerator operation rough.

For this reason, for example, even when attempting to start on an uphill slope on a snowy road, the driver may carelessly press the accelerator pedal, making it impossible to start. Of course, even if slip control were to be activated in such a case, this slip control would be activated after one slip has occurred, and as a result of this slip, the snow surface would be trampled, causing the potted plants on the road to become more and more has decreased and it is no longer possible to start using slip control.

Therefore, the present invention has been made in consideration of the following two circumstances, and provides a slip control device for a vehicle that solves the problem of inability to start, which tends to occur because a slip control device is attached. It is about providing.

(Means and effects for solving the problem) Based on the recognition that the problem described in L is derived from the sense of security that there is slip control, the present invention prohibits slip control at the time of starting. The system is designed so that the adjustment of the applied torque to the drive wheels is left entirely to the driver's accelerator work. Specifically, as shown in FIG. 18, a slip control device for a vehicle is provided which prevents excessive slip of the drive wheels against the road surface by controlling the torque applied to the drive wheels. As a premise, the configuration includes a vehicle start detecting means for detecting the start of the vehicle, and a slip control inhibiting means for receiving a signal from the vehicle start detecting means and prohibiting slip control when the vehicle starts. .

With this configuration, the driver performs careful accelerator work with the understanding that slip control will not operate when starting the vehicle.

(Example) Examples of the present invention will be described below based on the attached drawings.

Overview of the overall configuration In Figure 1, the automatic middle 1 has left and right front wheels 2 which are driven wheels.
．． It has four wheels: 3 and 4.5 left and right rear wheels that serve as driving wheels. At the front of the car 1, an engine 6 as a power source is installed in a tower.The torque generated by the engine 6 passes through a clutch 7, a transmission 8, a propeller shaft 9, and a differential gear lO, and then is sent to the left and right drives. The power is transmitted to the left and right rear wheels 4.5 as driving wheels via the shaft 11L1.11R. In this way, the car
It is said to be an FR type (front engine, rear drive).

The engine 6 as a power source has its intake passage 12
Load control, that is, control of generated torque is performed by a throttle valve 13 disposed in the engine. More specifically, the engine 6 is a gasoline engine, and the generated torque changes depending on the change in the intake air amount, and the intake air amount is adjusted by the throttle valve 13. The throttle valve 13 is electromagnetically controlled to open and close by a throttle actuator 14. Note that the throttle actuator 14 may be constituted by, for example, a DC motor, a step motor, or an appropriate device driven by fluid pressure such as oil pressure and controlled electromagnetically.

Each wheel 2-5 has a brake 21, 22, 23, respectively.
Alternatively, 24 are provided, and each of the brakes 21 to 24 is a disc brake. As is known, this disc brake includes a disc 25 that rotates together with the wheel and a caliper 26. This caliper 2
6 holds the brake pad and includes a wheel cylinder, and the brake pad is moved to the disc 25 with a force corresponding to the magnitude of the brake fluid pressure supplied to the wheel cylinder.
Braking force is generated by pressing against the

The mask cylinder 27 as a brake fluid pressure generation source is 2
It is of a tandem type having two discharge cls 27a and 27b. Brake pipe 28 extending from the discharge port 27a
is branched into two branch pipes 28a and 28b in the middle,
The branch pipe 28a is connected to the brake 22 for the right front wheel (the wheel cylinder thereof), and the branch pipe 28b is connected to the brake 2 for the left rear wheel.
Connected to 3. In addition, the brake pipe 29 extending from the discharge port 27b has two branch pipes 29a and 29b on the way.
The branch pipe 29a is connected to the brake 21 for the left front wheel, and the branch pipe 29b is connected to the brake 24 for the right rear wheel. In this way, the brake piping system is of the so-called two-system X type. An electromagnetic hydraulic pressure control valve 30 as a braking force adjusting means is installed in the branch pipes 28b and 29b for the brakes 23 and 24 for the rear wheels, which are the driving wheels.
Or 31 is connected. Of course, the brake fluid pressure generated in the mask cylinder 27 depends on the amount (depression force) of the brake pedal 32 by the driver.

Brake fluid pressure control go [! As shown in FIG. 2, each of the hydraulic pressure control valves 30, 31 has a cylinder 41 and a piston 42 slidably inserted into the cylinder 41. The piston 42 defines the inside of the cylinder 41 into a variable volume chamber 43 and a control chamber 44 . This variable volume chamber 43 is
It serves as a passageway for brake fluid pressure from the mask cylinder 27 to the brake 23 (24). Therefore, by adjusting the displacement position of the piston 42, the volume of the variable volume chamber 43 is changed, and the brake 23 (24)
This means that the brake fluid pressure can be increased, decreased or maintained.

The piston 42 is constantly urged by a return spring 45 in a direction in which the volume of the variable volume chamber 43 increases. Further, a check valve 46 is integrated into the piston 42. This check valve 46 is connected to the piston 4.
2 is displaced in the direction of decreasing the volume of the variable volume chamber 43, the inlet side to the variable volume chamber 43 is closed.

As a result, the brake fluid pressure generated in the variable volume chamber 43 acts only on the brake 23 (24) side, and does not act on the brake 21.22 of the front wheel 2.3 as a driven wheel. .

The displacement position of the piston 42 is adjusted by adjusting the control hydraulic pressure to the control chamber 44. To explain this point in detail, the supply pipe 48 extending from the reservoir 47 is branched into two in the middle, and one branch pipe 48R is connected to the valve 30.
The other branch pipe 48L is connected to the control chamber 44 of the valve 31. A pump 49 and a relief valve 50 are connected to the supply pipe 48, and a supply valve SV3 (SV2) consisting of an electromagnetic on-off valve is connected to the branch pipe 48L (48R). Each control chamber 44 is further connected to the reservoir 47 via a discharge pipe 51R or 51L, and a discharge valve SV4 (SVI) consisting of an electromagnetic on-off valve is connected to the discharge pipe 51L (51R).

During braking (slip control) using this hydraulic pressure control valve 30 (31), the check valve 46 basically prevents the brake from moving by operating the brake pedal 32. However, when the brake fluid pressure generated by the fluid pressure control valve 30 (31) is small (for example, during pressure reduction), the brake is applied by operating the brake pedal 32. Of course, the hydraulic control valve 30
(31), when the brake fluid pressure for slip control is not generated, the mask cylinder 27 and the brake 23 (24)
) are in communication, so normal braking action is performed due to the operation of the brake pedal 32.

The opening and closing of each valve 5VI-3V4 is controlled by a brake control unit UB, which will be described later. Brake fluid pressure status to brakes 23 and 24 and each valve 5V
The operational relationship with I-3V4 is summarized on the vest.

(Left space below) Overview of control unit configuration In Fig. 1, U is a control unit, which includes the brake control unit UB mentioned above, throttle control unit UT, and slip control control unit (US). It consists of The control unit UB controls the opening and closing of each valve 5VI-3V4 as described above based on the command signal from the control unit US, and
The throttle control unit UT controls the throttle actuator 14 based on a command signal from the control unit US.

The slip control control unit (US) is constituted by a digital computer, more specifically a microcomputer. This control unit US includes each sensor (or switch) 61, 62.
Signals from 64 to 68 are input. The sensor 61 detects the opening degree of the throttle valve 13. The sensor 62 detects whether the clutch 7 is engaged. The sensor 64 detects the rotational speed of the left front wheel 2 as a driven wheel, that is, the vehicle speed.

Sensors 65 and 66 detect the rotational speed of left and right rear wheels 4.5 as driving wheels. The sensor 67 is the accelerator 6
9, that is, the accelerator opening degree. The sensor 68 detects the amount of operation of the steering wheel 70, that is, the steering angle.

The sensors 64, 65, 66 are configured using, for example, a pickup, the sensors 61, 67, 68 are configured using, for example, a potentiometer, and the sensor 62 is configured using, for example, a potentiometer.
is constituted by a switch that operates ON and OFF, for example.

The control unit US basically consists of a CPU,
It is equipped with ROM, RAM, CLOCR, t-, and also has an input/output interface and an A/D or D/A converter depending on the input signal and output signal, but regarding these points. There is no difference from the usual one when using a microcomputer, so
A detailed explanation thereof will be omitted. Note that the maps and the like in the following explanation are stored in the ROM of the control unit 22) US.

Next, the control contents of the control unit U will be explained in order, and the slip rate S used in the following explanation shall be defined by the following equation (1).

WD: Number of revolutions of the driving wheels (4, 5) WL: Number of revolutions of the driven wheels (2) (vehicle speed) The throttle control unit UT provides feedback to the throttle valve 13 (throttle actuator 14) so that the target throttle opening is achieved. It is supposed to be controlled. During this throttle control, when slip control is not performed, control is performed so that the target throttle opening corresponds to a ratio of 1:1 to the operation amount of the accelerator 69 operated by the driver, and the accelerator opening at this time is FIG. 12 shows an example of the correspondence relationship between and the throttle opening degree. In addition, the control unit (UT) controls the first control unit during slip control.
Throttle control is performed so that the target throttle opening degree Tn calculated by the control unit US is achieved without following the characteristics shown in FIG.

Throttle valve 1 using control unit UT
In the embodiment, the feedback control No. 3 is performed by PI-FD sub-control in order to compensate for fluctuations in the response speed of the engine 6. That is, during slip control of the drive wheels, the opening degree of the throttle valve 13 is sub-controlled by PI-FD so that the current slip rate matches the target slip rate. More specifically, the target throttle opening degree Tn during slip control is calculated by the following equation (2).

Tn= Tn-1 -5ET -5ET -FP (WDr+-WDn-1) -D (WDn -2X WDn-1+
WDn-2)・・・・(2) WL: Number of rotations of driven wheels (2) WD: Number of rotations of driving wheels (4, 5) KP: Proportional constant KI: Integral constant FP: Proportional constant FD: Differential constant SET :Target slip rate (for slip control) L memory (
As shown in 2), the throttle opening degree Tn is feedback-controlled to the rotation speed of the driving wheels so as to reach a predetermined target slip rate SET. In other words, as is clear from equation (1) above, the throttle opening is determined by the target drive wheel rotation speed NET.
is controlled so that it becomes the following equation (3).

PI-FD using the control unit UT described above
The sub-control is shown in FIG. 3 as a block diagram, and "S'" shown in FIG. shows the value of each signal at the time of sampling.

During brake control slip control, the control unit UB
The rotation (slip) of the left and right drive wheels 4.5 is feedback-controlled to a predetermined target slip rate SET independently for the left and right wheels. In other words, brake control is expressed by the following equation (
Feedback control is performed so that the driving wheel rotation speed WBT set in step 4) is achieved.

In this embodiment, the target slip rate of 38 brakes is set to be larger than the target slip rate of the engine, SET, as will be described later. In other words, the slip control of this embodiment increases or decreases the engine output to a predetermined S ET (WET), and also increases or decreases the engine output to a predetermined S BT (WB
The frequency of use of the brake is reduced by increasing and decreasing the torque by the brake so that the torque becomes T). In this embodiment, feedback control that satisfies the above equation (4) is performed by I-FD sub-control that ensures stability. More specifically, the brake operation amount (operation 1 of the piston 44 in the valve 30.31
)Bn is calculated by the following equation (5).

Bn=Bn-1 + Kr (W Ln X--W Dn) 1-5B
? -F P (WDn -WDn-1) -F D (
WDn-2X WDn-1+ WDn-2)...(
5) KI: Integral coefficient KD: Proportional coefficient FD: Derivative coefficient When the above Bn is larger than O (when it is "positive"), the brake fluid pressure is increased, and when it is 0 or less, it is reduced. This increase/decrease in brake fluid pressure is controlled by the valve 5VI-
This is done by opening and closing 5V4. In addition, the adjustment of the increase/decrease speed of the brake fluid pressure is performed using the above valves SV1 to SV.
This is done by adjusting (duty control) the ratio of the opening/closing time (duty ratio) of No. 4, and the duty control is proportional to the absolute value of Bn determined by the above equation (5). Therefore, the absolute value of Bn is proportional to the rate of change in brake fluid pressure, and conversely, the duty ratio that determines the rate of increase/decrease also indicates Bn.

The I-FD sub-control by the control unit UB is shown in FIG. 4 as a block diagram.
"S'" shown in the figure is an "operator".

Tamayu”” 6 匪! 9''8141 An overall outline of the slip control by the control unit U will be explained with reference to FIG. The meanings of the symbols and numerical values shown in FIG. 5 are as follows. .

S=0.2 Slip rate at the start of Nislip control (SS) S=0.17: Target slip rate by brake (S BT
) S = 0.09 Slip rate when stopping slip control by brake (S BC) S = 0.06: Target slip rate by engine (S ET
Note that the above numerical values are based on data obtained by actually driving on ice with spiked tires.

In this embodiment, the slip rate S=0.09 at the time when the brake slip control is stopped remains unchanged. on the other hand,
The target slip rate SOT by the brake, the target slip rate SET by the engine, and the slip rate SS at the start of slip control are changed depending on the road surface condition, etc. In Fig. 5, as an example 1, I[, 17J , r
o, 06J or ro, 2''.

Then, the slip rate s'=o at the start of the slip control.

2 uses the slip rate at the time when the maximum grip force is generated when using a spiked tire (see the solid line in FIG. 13). In this way, the reason why the slip rate at the start of slip control is set to 0.2 is so that the actual slip rate when this maximum grip force is obtained can be determined, and this maximum grip force Set the target slip rate by engine and brake according to the slip rate at the time of occurrence.
, SET are corrected. In addition, the solid line in FIG. 13 shows how the magnitude of grip force and lateral force (shown as a friction coefficient with respect to the road surface) when using a spiked tire changes in relation to the slip rate. Moreover, the broken line in FIG. 13 shows the relationship between grip force and lateral force when using normal tires.

(Left below) Based on the above, FIG. 5 will be explained as time goes on.

■to ”tl Since the slip rate S does not exceed S = 0.2, which is the slip control start condition, slip control is not performed. In other words, when the slip of the drive wheels is small, acceleration is not performed without slip control. (driving using a large grip force).Of course, in this case,
The characteristics of the throttle opening with respect to the accelerator opening are the 12th
It is uniformly determined as shown in the figure.

(t1 to t3) Slip control is started and the slip rate is equal to or higher than the W point (S=0.09) during slip control by the brake. At this time, since the slip rate is relatively large, slip control is performed by reducing the torque generated by the engine and braking by the brake. Also, since the target slip rate of the brake (S = 0.17) is larger than the target slip rate of the engine (S = 0.06), the brake is not pressurized when there is a large slip (S > 0, 17). However, when there is a small slip (S<0, 17), the brake is not pressurized and the slip is controlled only by the engine so that the slip converges.

(Φt3~L4 Slip control is performed only by the engine.

(2) Since the accelerator 69 is fully closed by the driver after t4, the slip control is discontinued. At this time, the throttle valve 13
Even if the opening degree is left to the driver's will, there is no risk of slipping again because the torque has been sufficiently reduced. In addition to fully closing the accelerator, in the embodiment, the slip control is canceled when the target throttle opening due to the slip control is lower than the throttle opening determined by FIG. 12, which corresponds to the accelerator opening operated by the driver. I also try to do this when it gets smaller.

Next, while referring to the flowcharts in FIGS. 6 to 11,
The details of slip control will be explained. Note that in the following explanation, P indicates a step.

FIG. 6 (Main) After initializing the system at Pi and confirming that the vehicle is running at P2, it is determined at P3 whether the accelerator 69 is fully closed. NO in this P3
When it is determined that this is the case, it is determined in P4 whether or not the current throttle opening is larger than the accelerator opening.

When the determination in P4 is NO, it is determined in P5 whether or not slip control is currently being performed. This determination is made by checking whether or not the slip control flag is set. When the determination in P5 is NO, it is determined in P6 whether or not a slip has occurred that requires slip control. This determination is made by checking whether at least one of the slip flags for the left and right rear wheels 4.5, which will be described later, is set. When the determination in P6 is NO, the process moves to P7 and the slip control is stopped (normal driving).

If YES is determined in P6, the process moves to P8, where the slip control flag is set.

Subsequently, in P9, the initial value of the target slip rate SET for the engine (throttle) (O, OS in the embodiment) is set, and in PIO, the initial value of the target slip rate SBT for the brake (0 in the embodiment) is set. .17) is set, and thereafter, brake control is performed at Fil and engine control is performed at Pi2 for slip control. Note that the initial values in P9 and Plo are set based on the maximum acceleration G MAX obtained in the previous slip control.

When the determination is YES in P5, the process moves to the above-mentioned Pi, and the slip control is continued.

If YES is determined in P4, the slip control is no longer needed, and the process moves to Pi4. This Pi
In step 4, after the slip control flag is reset, the process moves to P7 and the slip control is stopped.

If YES is determined at P3, the brake is released at Pi3, and then the processes from P14 onwards are performed.

Control at Start (P2.1) When the vehicle is in the start state, that is, when the vehicle speed is zero (YES in P2), the process moves to P2.1 and slip control is prohibited. In this way, when starting,
By not performing slip control, vehicle start control is placed under complete control of the driver.

7 and 8 The flowchart in FIG. 7 interrupts the main flowchart in FIG. 6, for example, every 14 msec.

First, in P21, each sensor 61, 62, 64 to 6
Each signal from 8 is input for data processing. Next, slip detection processing is performed in P22 and throttle control processing is performed in P23, which will be described later.

The throttle control at P23 is performed according to the flowchart shown in FIG. First, in P27, it is determined whether the slip control flag is set, that is, whether slip control is currently being performed. If YES in P27, the process moves to P28, where the control of the throttle valve 13 is performed for slip control, that is, to achieve a predetermined target slip rate SET without following the characteristics shown in FIG. is selected. Also,
When the determination is NO in P27, the opening/closing control of the throttle valve 13 is selected to be left to the cartwheeler's will (according to the characteristics shown in FIG. 12) in P2O. After P28 and P2O, control is performed at P2O to achieve the target throttle opening.

FIG. 9 (Slip Detection Process) The flowchart in FIG. 9 corresponds to P22 in FIG. 7. This flowchart is for detecting whether or not a slip that is subject to slip control has occurred.

First, in P33, it is determined whether the clutch 7 is completely connected. If YES is determined in P33, a correction value α for slip determination is calculated in P34 according to the /X steering angle (see FIG. 14).

After this, in P35, it is determined whether the slip rate of the left rear wheel 4 as the left driving wheel is larger than the predetermined reference value 0.2 plus α in P34 (0,2+α). Ru. If the determination in P35 is YES, it is determined that the left rear wheel 4 is in a slip state, and the slip flag is set. Conversely, when the determination in P35 is No, the slip flag for the left rear wheel 4 is reset. Note that the E correction value α is set in consideration of the rotational difference between the inner and outer wheels (particularly the rotational difference between the driving wheel and the driven wheel) during turning.

After P36 or P37, P38, P39, P2O
In , the slit flag for the right rear wheel 5 is set or reset in the same manner as in P35, P36, and P37.

If the determination in P31 is No, the control ends immediately.

Fig. 10 (Engine control m) The flowchart shown in Fig. 10 is based on P12 of Fig. 6.
Compatible.

At P61, it is determined whether the slip has transitioned to a convergence state (whether it has passed time t2 in FIG. 5). If NO in P61, it is determined in P62 whether the slip rate S of the left rear wheel 4 is greater than 0.2. If NO in P62, it is determined in P63 whether the slip rate S of the right rear wheel 5 is greater than 0°2. If this P63 is NO, the left and right rear wheels 4.
5, it is determined whether only one side of the vehicle is under brake control, that is, whether the vehicle is traveling on a split road. P
If YES in 64, change the left and right rear wheels 4 and 4 in P65.
, 5, the current slip rate is calculated according to the drive wheel with the lower slip rate (select low). On the contrary, P64
If No in P66, the current slip rate is calculated according to the drive wheel with the larger slip rate among the left and right rear wheels 4.5 (select high).
If the answer is No at 63, the process also moves to P66.

The selection high at P66 allows the use of the brake to be further avoided by calculating the current slip rate in order to suppress the slip of the slippery drive wheel. On the other hand, the select low in P65 above is effective when driving on a split road where the friction coefficients of the road surface that the left and right drive wheels touch are different, while suppressing the slip of the drive wheel that is more likely to slip by the brake. This makes it possible to drive by taking advantage of the grip of the drive wheel on the weaker side.

In addition, in the case of this select low, in order to avoid overusing the brakes, it is advisable to take backup measures such as limiting the select low to a certain period of time, or stopping the select low when the brakes overheat.

After P65 and P66, the target opening degree Tn of the throttle valve 13 is calculated for slip control (feedback control) in P67. Of course, at this time, the target throttle opening (Tn) of the throttle valve 13 is set to realize the target slip rate SET set in P6, P66 or changed in P69, which will be described later.

On the other hand, if YES in P61, the process moves to P68 and the maximum acceleration G MAX of the vehicle I is measured (Fig. 5 t
2 time points) 0 Then, at P69, A to G at P68
Estimate the coefficient of friction of the road surface from X and determine the target slip rate SE for slip control using the engine (throttle) and brakes.
Change both T and SBT. Note that how to change the target slip rates SET and SBT will be described later.

FIG. 11 (Brake Control) The flowchart shown in FIG. 11 corresponds to the pH shown in FIG. 6.

First, in P81, it is determined whether or not the slip rate S of the right rear wheel 5 is greater than 0.09, which is the brake control stop point. When YES in P81, the operating speed Bn of the right rear wheel brake 24 is calculated in P82 (corresponding to Bn in the I-FD sub-control in FIG. 4). After that, in P83, the above-mentioned Bn is calculated as " It is determined whether or not the value is larger than "O". This determination determines whether or not the pressure increasing direction is the increasing pressure direction, assuming that the increasing pressure direction of the brake is positive and the pressure decreasing direction is negative. When YES in P83, the pressure is increased in P84 using the value of Bn set in P85.

If NO in P83, Bn is "negative" or "0".
”, so after converting Bn to an absolute value using P8E), 86
The pressure of the right brake is reduced (Bn output).

On the other hand, if NO in P81, it is time to cancel the brake control, so the right brake is released in P87.

After P84, P86, and P87, the process moves to P88, and the left brake 23 is subjected to pressure increase, pressure decrease, or brake release processing in the same manner as the right brake 24.

Target 4 rate SET, SBT (P69) The target slip rate SET, SET between the engine and brake changed in P69 is based on the maximum acceleration G WAX measured in P68, for example, as shown in Fig. 15. Modified as shown. As is clear from FIG. 15, in principle, the larger the maximum acceleration GWAX, the larger the target slip rates SET and SET should be. Limit values are set for each of the target slip rates SET and SBT.

Here, a description will be given of how the target fullness rate SET and the setting relationship with SET affect the driving sensation of the automobile 1.

■The grip force SET and SBT of the drive wheels are offset in the vertical direction in FIG. 15 as a whole. Then, to increase the grip force, perform an upward offset. In other words, as shown in Fig. 13, the characteristics of spiked tires include a slip rate of 0.2.
Since the coefficient of friction is increasing up to about 0.3, the above can be said as long as the slip ratio is used within the range of 0.2 to 0.3.

(2) Feeling of Acceleration The feeling of acceleration changes by changing the "difference" between SET and SET, and the smaller this "difference" is, the greater the sense of acceleration becomes. That is, when SET is set to a value smaller than SBT as in the embodiment, brake control mainly acts when the slip rate is large, and engine control acts mainly when the slip rate is small. therefore,
When the "difference" between SET and SBT is made smaller, brake control and engine control come closer to working with almost the same distribution. In other words, the brakes are used to reduce the torque generated by the engine to drive the drive wheels, and if the torque is rapidly increased for acceleration, simply loosening the brakes will increase the torque to the drive wheels without delay in response. do.

(N) Increase smoothness of acceleration SBT, that is, make it relatively larger than SET. This increases the priority of engine control, making smooth torque changes, which are the advantage of engine control, more effective. This means that it can be generated.

<4) Stability during cornering Reduce SET, that is, make SET relatively smaller than SBT. As is clear from Fig. 13, this means that the slip rate S =
In the range of 0.2 to 0.3 or less, by lowering the target slip ratio, the grip force of the driving wheels is reduced, while the lateral force is made as large as possible to increase the bending force.

The selection of the above-mentioned characteristics (modes) from (1) to (4) may be manually selected (mode selection) depending on the driver's preference, for example.

In the embodiments described above, the target slip rate is
Since the SBT for the brake is set larger than the SET for the engine, brake control is not performed in small slip conditions, so it is possible to reduce the frequency of use, and it is also possible to control the brake even in the event of a large slip. The burden will be reduced. In addition, since there is a point (S Be) between SBT and SET where the brake slip control is stopped, the brake pressure is sufficiently low when the brake control is stopped.
Sudden torque fluctuations are less likely to occur.

(Hereinafter in the margin) Although one embodiment has been described, the present invention is not limited to this, and includes, for example, the following case.

(2) The magnitude relationship between the brake control and the engine control with respect to the target slip rate may be reversed from that of the embodiment, or may be the same. Furthermore, slip control may be performed by only one of brake control and engine control. Of course, in addition to the above, a transmission (particularly effective in the case of a continuously variable transmission) or the like can also be used to adjust the torque applied to the drive wheels.

(2) It is preferable to adjust the generated torque of the engine 6 by changing and controlling the factors that most affect the output generated by the engine. In other words, it is preferable to adjust the generated torque by so-called load control, and in the case of an automatic engine (for example, a gasoline engine), by adjusting the mixture amount, and in the case of a diesel engine, by adjusting the amount of fuel injection. is preferred. However, this load control is not limited to this, and may also be carried out by adjusting the ignition timing in the case of an Otto type engine, or by adjusting the fuel injection timing in the case of a diesel engine. In the case of an engine, this may be done by adjusting the supercharging pressure.Of course, the power source is not limited to an internal combustion engine, but may also be an electric motor.
The generated torque in this case may be adjusted by adjusting the power supplied to the motor.

■The automobile 1 may have front wheels 2 and 3 as drive wheels (FF city) or may have all four wheels as drive wheels (4WD vehicle).

■In order to detect the slip state of the drive wheels, it is possible to directly detect the rotation speed of the drive wheels as in the embodiment, but it is also possible to predict the slip state according to the state of the vehicle. In other words, it may be detected indirectly. Such vehicle conditions include, for example, an increase in the generated torque or rotational speed of the power source, a change in the degree of accelerator opening, a change in the rotation of the drive shaft, the steering condition (cornering), and the floating condition of the vehicle body (acceleration). , loading capacity, etc. In addition to this, road surface conditions such as high and low atmospheric temperatures, rain, snow and ice burns can be detected automatically or manually input.
It is also possible to make the prediction of the slip state of the drive wheels even more appropriate.

■Brake fluid pressure control circuit and sensor 64.6 in Figure 2
5.66 can utilize the existing ABS (anti-brake lock system).

Note: A low p road may be added as a condition for prohibiting slip control uJ (FIG. 6) in step P2.1.

(7) Furthermore, in addition to the condition (2) above, the fact that the road is an uphill slope may be added.

(Effects of the Invention) As is clear from the above description, the present invention does not perform slip control at the time of starting, so the driver does not have excessive expectations for slip control and can perform starting control under his own control. This makes it possible to prevent careless accelerator work when starting the vehicle. Therefore, it is possible to avoid a situation where the vehicle cannot start on a low road based on the sense of security that the slip control device is provided.

[Brief explanation of the drawing]

FIG. 1 is an overall system diagram showing one embodiment of the present invention. FIG. 2 is a diagram showing an example of a brake fluid pressure control circuit. FIG. 3 is a block diagram when performing feedback control of the throttle valve. FIG. 4 is a block diagram when feedback controlling the brakes. FIG. 5 is a graph schematically showing a control example of the present invention. 6 to 11 are flowcharts showing control examples of the present invention. FIG. 12 is a graph showing the characteristics of throttle opening relative to accelerator opening when sleep control is not performed. FIG. 13 is a graph showing the relationship between the grip force and lateral force of the driving wheels in terms of the relationship between the slip rate and the friction coefficient with respect to the road surface. FIG. 14 is a graph showing correction values when the slip rate at the start of slip control is corrected according to the steering wheel angle. FIG. 15 is a graph showing an example of a map used when determining the target slip rate. FIG. 16 is an overall configuration diagram of the present invention. l2 Automobile 2.3; Front wheels (driven wheels) 4.5: Rear wheels (driving wheels) 6: Engine (power source) 7: Clutch 8: Transmission 13; Throttle valve. 14: Throttle actuator 21 to 24 Brake 27: Mask cylinder 30.31: Hydraulic pressure control valve 32 Brake pedal 61: Sensor (throttle opening) 62: Sensor (clutch) 64: Vehicle speed (driven wheel rotation speed) 65.66 : Sensor (driving wheel rotation speed) 67: Sensor (accelerator opening degree) 69: Accelerator SVI to SV4 : Electromagnetic opening/closing valve U: Control unit Fig. 2 Fig. 9 Fig. S Fig. 10 ○2 Fig. 1I Fig. 12 Fig. 14 C] To 1 hand sword triangle Fig. 13 S (r Korigaku) Fig. 15 MAX

Claims (1)

[Claims] (1) In a vehicle slip control device that prevents excessive slip of the driving wheels relative to the road surface by controlling the torque applied to the driving wheels, a vehicle start detection means for detecting the start of the vehicle; A slip control device for a vehicle, comprising: a slip control prohibition means that receives a signal from the vehicle start detection means and prohibits slip control when the vehicle starts.