JPH0454232A - Traction controller of vehicle - Google Patents

Abstract

PURPOSE:To eliminate slipping surely while preventing deterioration of a driving performance by providing a load variable limiting means which limits variation of load of an auxiliary device driven by an engine during the operation of a driving force suppressing means at the time when a slip condition of driving wheels is detected. CONSTITUTION:In a traction control unit 50, when slipping of rear wheels 3, 4 is detected by wheel speed signals d-g from wheel speed sensors 51-54 which detect rotational speeds of wheels 1-4 respectively, control force is applied to the rear wheels 3, 4 by control pressure according to a slipping condition by opening and closing switching valves 37, 38 and relief valves 39, 40 on control pressure supply pipes 35, 36 for the rear wheels by means of duty control. When the suppressing control of driving force is applied at the time of the slipping, an ignition timing and throttle opening are controlled so as to decrease output torque of an engine. In this case, in an ECU 60, variation of load on auxiliary devices (alternator 71, compressor 72 for air conditioner and the like) driven by the engine is controlled to be limited during the driving force suppressing control.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a traction control device that reduces driving force when a drive wheel slips to eliminate the slip.

(Prior Art) Generally, the driving force of a vehicle is controlled by adjusting the engine output through the driver's accelerator operation and by operating the transmission, but the driving force transmitted to the drive wheels depends on the coefficient of friction of the road surface. In order to prevent the slippage of the drive wheels due to excessive force, a traction control device has been put into practical use that automatically controls the drive force in a direction that suppresses it, in addition to the control by the driver's operation as described above.

In this case, as a method of the driving force suppressing means using this device, for example, as disclosed in Japanese Patent Application Laid-open No. 57-22948, a method of applying braking force to wheels with excessive driving force using a brake system is possible. There are methods for reducing engine output torque, methods for reducing engine output torque, and methods for using these together.6 In addition, methods for reducing engine output torque include methods for stopping fuel supply to some or all cylinders, and methods for reducing ignition timing. There is a method of correcting control to the retard side, a method of correcting control of the opening of the throttle valve in the decreasing direction, etc.

(Problem to be Solved by the Invention) By the way, the above-mentioned drive force suppression control is performed extremely precisely so that the slip of the drive wheels is reliably eliminated by reducing the drive force to the minimum necessary level. However, during this control, if the load of the auxiliary equipment driven by the engine, such as the alternator or air conditioner compressor, fluctuates, the output torque of the engine transmitted to the drive wheels will also fluctuate, making it difficult to accurately control the driving force. Control will be lost. Therefore, for example, when the load on the auxiliary equipment decreases, the driving force becomes relatively excessive and the slip of the drive wheels is not resolved, and when the load on the auxiliary equipment increases, the driving force decreases more than necessary. This may cause problems such as deterioration of driving performance.

SUMMARY OF THE INVENTION Therefore, the present invention aims to improve the controllability of driving force control due to changes in the load of engine-driven auxiliary equipment in a vehicle in which driving force suppression control, that is, traction control, is performed to eliminate the slip of the drive wheels as described above. An object of the present invention is to prevent the deterioration of driving performance, thereby reliably eliminating the slip of drive wheels while avoiding deterioration of driving performance.

(Means for Solving the Problems) In order to solve the above problems, the present invention is characterized by having the following configuration.

First, the invention according to claim 1 of the present application (hereinafter referred to as the first invention) includes a slip detection means for detecting a slip state of a drive wheel, and a method for detecting a slip state of a drive wheel when the slip state of the drive wheel is detected by the detection means. In a traction control device for a vehicle, the traction control device for a vehicle is equipped with a driving force suppressing means for suppressing the driving force so as to eliminate the load that limits fluctuations in the load of an auxiliary machine driven by the engine while the driving force suppressing means is in operation. It is characterized by providing a variation limiting means.

A unique invention according to claim 2 (hereinafter referred to as the second invention) is a traction control device equipped with a slip detection means and a driving force suppressing means similar to the first invention, in which the driving force suppressing means is The present invention is characterized in that a load fixing means is provided for fixing the load of the auxiliary equipment driven by the engine to a low load state during operation.

(Function) With the above configuration, firstly, according to the first invention, while the driving force suppressing means is in operation, the load fluctuation limiting means limits the fluctuation in the load of the engine-driven auxiliary equipment. Accompanying variations in the engine output torque or the driving force transmitted to the drive wheels are also limited. Therefore, the optimum driving force set according to the slip state of the drive wheels is maintained, and slips are reliably eliminated while avoiding deterioration of driving performance.

Further, according to the second invention, when the driving force suppressing means is activated,
Since the load of the auxiliary equipment is fixed to a low load state by the load fixing means, the optimum driving force set according to the slip state of the drive wheels is maintained, as in the first invention. In particular, according to the second invention, since the load of the auxiliary equipment is fixed at a low load state, traction control is performed while the engine output torque is generally low.
Therefore, the hunting width associated with 81161 is reduced, and the accuracy and stability of the traction control are further improved.

(Example) Examples of the present invention will be described below. In addition, in the following embodiments, when a drive wheel slips due to excessive drive force, the drive force is suppressed by applying braking force to the drive wheel, and the drive force is controlled by reducing the output torque of the engine. Force suppression control is performed.

As shown in FIG. 1, in the vehicle according to this embodiment, the left and right front wheels 1.2 are driven wheels, and the left and right rear wheels 34 are driving wheels.
The output torque of the engine 5 is transmitted from the transmission 6 to the left and right rear wheels 3 and 4 via a propeller shaft 7, a differential device 8, and left and right drive shafts 9 and 10.

Each of the wheels 1 to 4 includes discs lla to 14a that rotate integrally with these wheels, and calipers llb to 14b that brake the rotation of these discs lla to 14a by receiving braking pressure. Brake device 11 consisting of
- 14 are provided, respectively, and a brake control system 20 is provided that performs a braking operation on these brake devices 11 - 14.

This system 20 allows the brake pedal 21 to be operated by the driver.
It has a booster 22 using a hydraulic booster that increases the stepping force of the driver, and a mask cylinder 23 that generates braking pressure in response to the increased stepping force by the booster 22.

Front wheel braking pressure supply pipes 24.25 led from the mask cylinder 23 are connected to the calipers 11b and 12b of the brake devices 11.12 on the left and right front wheels 1 and 2, respectively, so that the brake pressure supply pipes 24.25 lead from the mask cylinder 23 to the calipers 11b and 12b of the brake devices 11.12 on the left and right front wheels 1 and 2. The front wheels 1 and 2 are braked by the applied braking force.

The booster 22 also includes a working pressure supply pipe 27 that supplies working pressure from the pump 26, and a working fluid return pipe 29 that returns excess working fluid generated in the booster 22 to the reservoir tank 28. are connected to the first braking pressure supply pipe 30 led from the booster 22 and the working pressure supply pipe 2.
A second braking pressure supply pipe 31 branched from the pump discharge side of No. 7
A first and a second electromagnetic on-off valve 32 and 33 are respectively installed in the first and second on-off valves 32 and 33, and a one-way valve 34 is installed in the first braking pressure supply pipe 30 in parallel with the first on-off valve 32. . Also,
The first and second braking pressure supply pipes 30.31 are joined at a point X, and from the joining point X, the calipers 13b, 14b of the brake devices 13.14 on the left and right rear wheels 3, 4! , 1:t
Brake pressure supply pipes 356 for Ik wheels are guided, and on these brake pressure supply pipes 35.36 are electromagnetic on-off valves 37.38 and electromagnetic relief valves 39.4.
0 and 0 are set respectively.

A traction control unit (hereinafter referred to as T or RCU) 50 is provided, which controls the on-off valves 31, 32, 37.38 and the relief valves 39.40.
With the braking force control signals a, b, and c from the TRCU 3O, the first on-off valve 32 opens and the second on-off valve 33 closes as shown in the figure, and the braking pressure supply pipes 35 and 36 for the rear wheels are opened and closed. Valve 3
7.38 is open, the braking pressure corresponding to the depression force of the brake pedal 21 generated by the booster 22 is applied to the first braking pressure supply pipe 30 and the rear wheel braking pressure supply pipe 35.
．． 36 to the calipers 13b and 14b of the brake devices 13.14 on the left and right rear wheels 3.4, and the rear wheels 3 and 4 are respectively braked with a braking force corresponding to these braking pressures.

In addition, the TRCU 3O inputs wheel speed signals d, e, f, and g from wheel speed sensors 51 to 54 that detect the rotational speed of each wheel 1 to 40, respectively, and adjusts the rear wheel 3 based on these signals d to g. , 4 is controlled.

When performing this control, the first on-off valve 32 is closed and the second on-off valve 33 is opened, so that the working pressure generated by the pump 26 is directly applied to the rear wheels as braking pressure without going through the booster 22. The brake pressure is supplied to the brake pressure supply pipes 35 and 36.

The signals d~ from each of the wheel speed sensors 51 to 54 are
When the slip of the rear wheel 3.4 is detected by When it is detected that the rear wheel brake pressure supply pipe 35
．． By opening and closing the on-off valves 37, 38 and relief valves 39, 40 above 36 by duty control, braking force is applied to the rear wheels 3, 4 with braking pressure according to the slip state. .

On the other hand, in this embodiment, the suppression control of the driving force when the rear wheels 3 and 4 slip is performed by controlling the engine by controlling the ignition timing and controlling the throttle opening in addition to controlling the braking force as described above. It is also done by controlling the output torque,
For these 4f controls, an engine control unit (hereinafter referred to as ECU) receives the traction operation signal from the TRCU 3O and controls the ignition timing and throttle opening so as to reduce the output torque of the engine 5.
) 60 are provided.

This ECU 60 sets the ignition timing based on the engine speed and throttle opening detected by an engine speed sensor 61 and a throttle opening sensor 62, respectively. Igniter 64 to ignite plugs 63...63
The ignition timing control signal i is output to. And this signal i
As a result, the spark plugs 63...63 of each cylinder are ignited via the ignition coil 65 and distributor 66 at the timing according to the operating condition.
When inputting the traction activation signal from
The CU 60 corrects the ignition timing in a retarded direction according to preset characteristics, thereby reducing the engine output torque.

The ECU 60 also controls the accelerator pedal 6 operated by the driver when a traction activation signal is input.
7 and a throttle valve 69 provided in an intake passage 68 of the engine. This throttle adjustment mechanism 70 normally closes the throttle valve 69 WI according to the amount of depression of the accelerator pedal 67, but when receiving the control signal j from the ECU 60, the throttle adjustment mechanism 70 closes the throttle valve WI according to the amount of depression of the accelerator pedal 67. Due to this characteristic, the opening degree of the throttle valve 69 is reduced, which also reduces the engine output torque.

As described above, when the rear wheels 3 and 4 slip, the braking force is applied to the rear wheels 3.4 by the operation of the TRCU 3O, and the engine output torque is also reduced via the ECU 60. The slip of the rear wheel 3.4 is eliminated, but in that case, the magnitude of the braking force applied to the rear wheel 3.4 and the amount of decrease in engine output torque,
In other words, the amount of reduction in driving force is controlled to a value that allows slips to be reliably and quickly eliminated, while still maintaining good running performance.

In addition to the above configuration, this embodiment is provided with an alternator 71 and an air conditioner compressor 72 as auxiliary machines driven by the engine 5. The alternator 71 has a variable power generation capacity by controlling its field current, and the compressor 7
2 is also variable in capacity, and the load they exert on the engine 5 changes depending on its capacity. And TRCU 50
When a traction operation signal is input to the ECU 60, the ECU 60 controls the operation or capacity of the alternator 71 and compressor 72 based on the load control signal kl.

Next, the control operation for the alternator 71 and compressor 72 by the ECU 60 during this traction control will be explained according to a flowchart.

First, to explain the operation of the first embodiment shown in FIG. 2, in this embodiment, the ECU 60
The ECU 60 waits for a traction activation signal to be input from the RCU 3O, and when the signal is input, that is, when the rear wheels 3 and 4 slip and traction control is started, the ECU 60 activates the alternator 71 in step S2. and the capacity of the air conditioner compressor 72 are fixed at the current state, thereby prohibiting variations in the load acting on the engine 5. Then, in step S, control is performed to suppress the engine output torque by reducing the throttle opening degree and retarding the ignition timing.

As a result, the control of the driving force of the rear wheels 3 and 4 is controlled by the engine 5.
The load on the alternator 71 and compressor 72 driven by It will be done often.

If it is determined in step S4 that the traction control has ended, the ECU 60 cancels the change prohibition control on the capacities of the alternator 71 and compressor 72 in step S5, and performs normal control that changes these capacities according to the driving state. resume.

Next, to explain the operation of the second embodiment shown in FIG. 3, in this embodiment as well, the ECU 60 performs T
The controller waits for input of a traction operation signal from the RCU 50, and when the signal is input, the value of the traction flag F is determined in step S12. This flag F is initially O, so next step S13 is executed,
The timer is set and the flag F is set to 1.

Next, in step S14, the ECU 60 determines whether the count value T of the timer is greater than a predetermined value To, that is, whether a predetermined time to has elapsed since the input of the traction operation signal. If the predetermined time to has elapsed (T≦To), step S15 is first executed to determine whether or not the air conditioner is operating, and if it is, step S16. In Slf, the capacity of the air conditioner compressor 72 is controlled to be fixed at the set value C2. In this case, this set value C2 is smaller than that during normal air conditioner operation, as shown by the symbol A in the fourth factor. It is considered a value. Further, the ECU 60 performs step S18+S
At step 19, control is performed to fix the power generation capacity of the alternator 71 to a set value C1, but this set value C1 is also set to a smaller value than during normal operation, as indicated by the symbol in FIG.

Then, in step 520, 1 is added to the timer count value T, and in step S21, control is performed to suppress the engine output torque by reducing the throttle opening and retarding the ignition timing. As a result, traction control is performed with the loads of the alternator 71 and compressor 72 fixed on the low load side and with the overall engine output torque being low, and therefore the hunting width of the control is reduced. getting smaller,
This traction control will be performed more stably and accurately.

In addition, in this embodiment, when a predetermined time to has elapsed from the input of the traction operation signal (T>To)
, the ECU 60 executes steps S14 to S22, returns the capacity of the alternator 71 and the compressor 72 to normal values according to the operating state, and performs traction control in this state, as shown in the fourth column C and 2. Continue. In other words, the alternator 71 and the compressor 7
Fixing the load in step 2 to the low load side is only recommended immediately after traction control is started from normal driving conditions, especially when control is likely to become unstable. However, as shown by chain lines E and B in Fig. 4, the loads of the alternator 71 and compressor 72 are fixed to the low load side until traction control is completed. In addition, as shown by the chain lines H and H in FIG. It may also be possible to prevent disturbances in traction control due to fluctuations in .

Here, the auxiliary machines driven by the engine 5 are:
In addition to the alternator 71 and compressor 72, power steering pumps, active suspension pumps, etc. may also be considered.

(Effects of the Invention) As described above, according to the traction control device according to the present invention, the load of the auxiliary equipment driven by the engine is fixed or its fluctuation is limited during traction control, so the fluctuation of this load is Due to this, the engine output torque or driving force transmitted to the drive wheels fluctuates, causing problems such as slippage of the drive wheels that has been resolved occurring again, or driving force decreasing more than necessary and driving performance deteriorating. This eliminates the problem and allows traction control to be performed in a stable and accurate manner. In particular, according to the second invention, traction control is performed in a state where the engine output torque is generally low, and the hunting width is reduced, so that the accuracy and stability of traction control are further improved. Become.

[Brief explanation of the drawing]

The drawings show embodiments of the present invention; FIG. 1 is a system diagram of a traction control device, FIGS. 2 and 3 are flowcharts showing control operations of the first and second embodiments, respectively, and FIG. FIG. 7 is a time chart diagram showing the operation of the second embodiment. 3.4... Drive wheel (rear wheel), 5... Engine, 50
... Driving force suppressing means (traction control unit: TRCU), 60... Load fluctuation limiting means, load fixing means (engine control unit: ECU),
71.72...Auxiliary equipment (alternator, air conditioner compressor). Agent Fukuoka Shiran1u1; i Ujiko

Claims (2)

[Claims] (1) A slip detection means for detecting a slip state of the driving wheels, and a driving force suppressing means for suppressing the driving force so as to eliminate the slip state of the drive wheels when the slip state of the driving wheels is detected by the detection means. A traction control device for a vehicle according to the present invention, characterized in that the device is provided with load fluctuation limiting means for limiting changes in the load of an auxiliary machine driven by the engine while the driving force suppressing means is in operation. Traction control device. (2) A slip detecting means for detecting a slip state of the driving wheels, and a driving force suppressing means for suppressing the driving force so as to eliminate the slip state of the driving wheels when the slip state of the driving wheels is detected by the detecting means. A traction control device for a vehicle, characterized in that the vehicle is provided with load fixing means for fixing the load of an auxiliary machine driven by the engine to a low load state when the driving force suppressing means is activated. traction control device.