JPH0848232A - Vehicle auxiliary brake controller - Google Patents

Abstract

(57) [Summary] [Purpose] The objective is to prevent unstable behavior during auxiliary brake operation on low μ roads where slip is likely to occur and to improve running stability. [Structure] When the brake pedal is depressed and an operation command for the auxiliary brake is generated, the auxiliary brake is activated when the auxiliary brake operating condition is satisfied, in which the accelerator is OFF, the clutch is engaged, the engine speed is equal to or higher than a predetermined value, and the ABS is OFF. Even if the difference in wheel speed between the front wheels F _r and the rear wheels R _r is F _r −R _r ≈0
When the slip state is detected, the operation of the auxiliary brake is immediately prohibited (S1-8).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle auxiliary brake control device, and more particularly to a technique for improving running stability on a low μ road.

[0002]

2. Description of the Related Art In recent years, with the development of highways and the like, the output of engines has been increasing, and it has become necessary to strengthen the braking capacity of vehicles to match them. In particular, in the case of trucks, buses, etc. with a large total vehicle weight, there is a limit to the capacity increase of the main brake (foot brake), and the retarder, exhaust brake, engine compression brake (hereinafter referred to as the third brake), etc. By using the auxiliary brake of and the main brake together, the braking ability is improved.

[0003]

However, when the auxiliary brake is operated on a low μ road such as a snow road, the wheels may slip, and the occurrence of the slip may cause unstable behavior of the vehicle. There is a problem that there is
As a conventional auxiliary brake control technique, the applicant of the present invention has proposed a technique in which an exhaust brake is automatically operated to prevent a rear-end collision when a rear-end collision alarm device gives an alarm. No mention is made of the problem of slippage occurring with the operation of the auxiliary brake.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an auxiliary brake control device for a vehicle that immediately eliminates the unstable behavior of the vehicle that occurs when a slip occurs due to the operation of the auxiliary brake. To do.

[0005]

Therefore, in the auxiliary brake control device for a vehicle according to the first aspect of the present invention, as shown in FIG. 1, the auxiliary brake operation commanding means, the driving state detecting means, and the auxiliary When an operation command is issued from the brake operation command means, the control means for operating the auxiliary brake when the operating condition detected by the operating condition detecting means satisfies the auxiliary brake operating condition, and the slip detection for detecting the slip of the wheel And a prohibiting means for prohibiting the operation of the auxiliary brake when the slip detecting means detects a slip state.

In the invention according to claim 2, the slip detecting means, as indicated by the dotted line in FIG. 1, is based on a signal from the wheel speed detecting means for detecting the wheel speeds of the front wheels and the rear wheels. When the difference between the wheel speeds of the front wheels and the rear wheels is equal to or more than a predetermined value, the slip state is determined.

[0007]

When the auxiliary brake operation command means generates an auxiliary brake operation command, the control means establishes the auxiliary brake operation condition based on the detection signal from the operating state detection means. If so, activate the auxiliary brake. When the auxiliary brake is actuated, for example, as described in claim 2, it is monitored whether or not the slip detecting means is slipping based on the difference between the wheel speeds of the front wheels and the rear wheels detected by the wheel speed sensor. If the speed difference is equal to or more than a predetermined value, it is determined that the vehicle is in a slip state, and the prohibiting means immediately prohibits the operation of the auxiliary brake.

Thus, by releasing the auxiliary brake as soon as the slip occurs due to the operation of the auxiliary brake, the unstable behavior of the vehicle can be prevented and the running stability on a low μ road or the like can be improved. become able to.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 2 shows the system configuration of one embodiment of the present invention, and FIG. 3 shows the control block diagram of this embodiment. 2 and 3, the driving force of the engine 1 is transmitted to the rear wheel 4 side via the clutch 2 and the transmission 3. The engine 1 is provided with an electronic governor 5,
Further, a third brake unit 21 is provided which generates a braking force by operating the engine 1 as a compressor. In addition, an exhaust brake 23 driven by an exhaust brake actuator 24 is provided in the exhaust passage 6. Also, transmission 3
A retarder 26 driven by a retarder control actuator 27 is provided on the output shaft of the.

The electronic governor 5, as shown in FIG.
Drive control is performed by the electronic governor control unit 10 based on signals from the accelerator pedal sensor 12 and the engine rotation sensor 13 that detect the amount of depression of the accelerator pedal 11. Further, the third brake unit 21, the exhaust brake 23, and the retarder 26, which are auxiliary brakes, are also provided.
Is driven and controlled by the auxiliary brake control unit 20 based on signals from various sensors that detect the driving state of the vehicle.

40 is an ABS control unit,
During vehicle braking, the ABS valve 42 is controlled based on the wheel speed signals of the front and rear wheels detected by the wheel speed sensor 41 (only the rear wheels are shown in the figure, but the front wheels are also provided).
The braking force on the rear wheels 4 is controlled via the ABS actuator 43. These electronic governor control unit 10, auxiliary brake control unit 20 and ABS
The control units 40 are connected to each other so that signals can be transmitted.

The signal input to the auxiliary brake control unit 20 is a signal corresponding to the depression amount from the brake pedal sensor 32 for detecting the depression amount of the brake pedal 31, and the clutch for detecting the depression position of the clutch pedal 33. An ON / OFF signal from the pedal switch 34, a signal from the vehicle speed sensor 35, a signal from the accelerator pedal sensor 12 input via the electronic governor control unit 10, a signal from the engine rotation sensor 13, and an ABS control unit. Wheel speed sensor via 40
41 is a signal from the like.

The auxiliary brake control unit 20 is
Based on these various input signals, when the signal from the brake pedal sensor 32 as the auxiliary brake operation command means is input, as shown in the flowcharts of FIGS. 5 and 6, the accelerator pedal sensor 12, the engine rotation sensor
13. From the signals from the clutch pedal switch 34 and the ABS control unit 40, it is judged whether or not the driving state at that time satisfies the auxiliary brake operating condition, and further,
Wheel speed sensor 41 via ABS control unit 40
From the signal from, it is judged whether or not it is in the slip state, and based on these judgments, the third brake control valve 2
2. Control signals are output to the exhaust brake control valve 35 and the retarder control valve 28 to output the third brake unit 21 and the exhaust brake 23, respectively.
It also controls the operation / non-operation of the retarder 26.

Therefore, the accelerator pedal sensor 12, the engine rotation sensor 13, the clutch pedal switch 34 and the wheel speed sensor 41 correspond to the driving state detecting means, and the auxiliary control unit 20 includes the controlling means, the slip detecting means and the prohibiting means. It has a function. Then, the brake pedal sensor 32 generates an output voltage corresponding to the amount of depression of the brake pedal 31, as shown in FIG. Fig. 4 shows the relationship between the pedal stroke and the output voltage.
It shows in (B).

In the auxiliary brake control unit 20, according to the output voltage of the brake pedal sensor 32,
When the output voltage is less than that shown in FIG. 4, the auxiliary brake is not activated. When the output voltage is less than the above range, only the exhaust brake 23 is activated, and when the output voltage is less than the above range, the exhaust brake 23 and the third brake unit 21 are activated. , The third brake unit 21 and the retarder 26 are operated.

Next, the auxiliary brake control operation of the apparatus of this embodiment will be described with reference to the flow charts of FIGS. When the brake pedal 31 is depressed and the output voltage is input from the brake pedal sensor 32 to the auxiliary brake control unit 20, it is determined that the auxiliary brake operation command is input, and the auxiliary brake control operation shown in the flowcharts of FIGS. 5 and 6 is started. To be done.

First, in step 1, it is judged whether or not the output voltage of the brake pedal sensor 32 is within the range shown in FIG. 4 (B) or less. If YES, in steps 2 to 5 the judgment of the operating state at that time is made. I do. That is, in step 2, it is determined whether the accelerator pedal 11 is not depressed (OFF) based on the signal from the accelerator pedal sensor 12 input via the electronic governor control unit 10, and in step 3, the clutch Pedal switch 34 is ON
It is determined whether or not (clutch connection state), and in step 4,
Based on a signal from the engine rotation sensor 13 input via the electronic governor control unit 10, it is determined whether the engine rotation speed is equal to or higher than a predetermined rotation speed (for example, 900 RPM), and in step 5, the signal from the ABS control unit 40 is detected. Based on this, it is determined whether the ABS is OFF (non-operation).

Further, in step 6, the wheel speed sensor
The difference between the wheel speed R _r of the front wheel speed F _r and the rear wheels (F _r -R _r) it is determined whether F _r -R _r ≒ 0 based on a signal from the 41, the determination result is YES If it is, it is judged that it is not a slip. Then, the determinations in steps 2 to 6 are all YE.
In the case of S, the routine proceeds to step 7, where an actuation signal is output to the exhaust brake control unit valve 25, and the exhaust brake 23 is actuated via the exhaust brake actuator 24 to actuate the exhaust brake which is one of the auxiliary brakes.

If a slip occurs and a wheel speed difference between the front wheels and the rear wheels occurs during the operation of the exhaust brake, the determination at step 6 becomes NO, and immediately at step 8, the operation of the exhaust brake is prohibited. When the determination in step 1 is NO, the process proceeds to step 9, and it is determined whether or not the output voltage of the brake pedal sensor 32 is in the range below the above. If the determination is YES in steps 10 to 14, the above-mentioned step 2 is performed. The same determination operations as in steps # 6 to # 6 are performed, and when all the determination results in each step are YES, the exhaust brake 23 and the third brake unit 21 are operated in steps 15 and 16. On the other hand, the judgment in any of steps 10 to 13 is NO.
When it is, it is determined that the auxiliary brake operating condition is not satisfied, and if the determination in step 14 is NO while the exhaust brake 23 and the third brake unit 21 are operating, it is determined that slip has occurred, and in steps 17 and 18, Exhaust brake 23
And prohibiting the operation of the third brake unit 21.

When the determination in step 9 is NO, the process proceeds to step 19, and it is determined whether or not the output voltage of the brake pedal sensor 32 is above, and if YES, steps 20 to 24.
In the above, the same determination operation as in steps 2 to 6 and steps 10 to 14 described above is performed, and the determination result of each step is Y.
Exhaust brake 23 in steps 25 and 26 during ES
And the 3rd brake unit 21 is operated. Further, in step 27, it is determined based on the signal from the vehicle speed sensor 35 whether or not the vehicle speed is a predetermined value (for example, 5 km / h) or more, and when it is the predetermined value or more, the retarder 26 is also operated in step 28. If the speed is lower than the predetermined value, the process proceeds to step 31, and the retarder 26 is deactivated. On the other hand, if any of the determinations in steps 20 to 23 is N
When it is O, it is determined that the auxiliary brake operating condition is not satisfied, and when the determination in step 24 is NO while the exhaust brake 23, the third brake unit 21 and the retarder 26 are operating, it is determined that slip has occurred and step 29 , 30, 31 deactivate the exhaust brake 23, the third brake unit 21 and the retarder 26.

When the determination in step 19 is NO, it is determined that the output voltage of the brake pedal sensor 32 is less than that, and it is determined that the auxiliary brake is unnecessary, and in steps 29, 30, 31, the exhaust brake 23, the third brake. Brake unit 21
And all auxiliary brakes on the retarder 26 are deactivated.
As described above, in the device of the present embodiment, when slip occurs during the operation of the auxiliary brake, the operation of the auxiliary brake is immediately prohibited, so that the vehicle is unstable on a low μ road or the like where slip is likely to occur. The behavior can be prevented and the running stability of the vehicle can be improved.

In addition, depending on the amount of depression of the brake pedal 31, only the exhaust brake is operated in the range where the depression amount is small, and the exhaust brake and the third brake are operated in the range where the depression amount is in the middle. When the number is large, all the three auxiliary brakes of the exhaust brake, the third brake and the retarder are operated, so that the auxiliary braking force can be set appropriately according to the required braking force.

In the above-mentioned embodiment, the auxiliary brake is operated in conjunction with the brake pedal 31, and the example in which the brake pedal 31 is used as the operation command means of the auxiliary brake is shown. However, as shown in FIG. It is also possible to separately provide an auxiliary brake actuation switch 51 of a type, and use this actuation switch 51 as actuation command means, and drive and control the auxiliary brake by this operation. In this case, the position of the operation switch 51 is detected by a potentiometer, etc., and the position signal is input to the auxiliary brake control unit 20.As with the brake pedal, depending on the lever operation position, the exhaust position is set at. All the three auxiliary brakes of the exhaust brake, the third brake and the retarder may be operated at the position of only the brake, and at the position of the exhaust brake and the third brake. The control operation in this case is the same except that the steps 1, 10, and 21 in the flowcharts of FIGS. 5 and 6 are replaced with the lever position determination in the operation step 51.

[0024]

As described above, according to the first aspect of the present invention, during the operation of the auxiliary brake, slip is detected based on the wheel speed of the front wheels and the rear wheels as described in, for example, Since the auxiliary brake is released immediately when a slip occurs, the unstable behavior of the vehicle due to the occurrence of slip can be prevented, and especially the running stability of the vehicle on low μ roads where slip easily occurs is improved. it can.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a claim corresponding to a vehicle auxiliary brake control device according to the present invention.

FIG. 2 is a system configuration diagram of a first embodiment of a vehicle auxiliary brake control device according to the present invention.

FIG. 3 is a control block diagram of the above embodiment.

4A and 4B are diagrams illustrating the operation of the brake petal sensor according to the above-described embodiment. FIG. 4A is a diagram showing a brake pedal depressing state, and FIG. 4B is a relationship between a depressing state and a sensor output in FIG. 4A. Figure

FIG. 5 is a flowchart showing the control operation of the above embodiment.

FIG. 6 is a flowchart showing the control operation of the above embodiment.

FIG. 7 is a diagram showing an auxiliary brake actuation switch used in a second embodiment of the present invention.

[Explanation of symbols]

 12 Accelerator pedal sensor 13 Engine rotation sensor 20 Auxiliary brake control unit 21 3rd brake unit 23 Exhaust brake 26 Retarder 32 Brake pedal sensor 34 Clutch pedal switch 40 ABS control unit 41 Wheel speed sensor

Claims (2)

[Claims] 1. An auxiliary brake operation commanding means, an operating condition detecting means, and an operating condition detected by the operating condition detecting means when an operating command is generated from the auxiliary brake operating commanding means satisfies an auxiliary brake operating condition. Control means for activating the auxiliary brake when the vehicle is in a slip state, slip detecting means for detecting a wheel slip, and prohibiting means for inhibiting the operation of the auxiliary brake when the slip detecting means detects a slip state. An auxiliary brake control device for a vehicle characterized by the above. 2. The slip detecting means is in a slip state when the difference between the wheel speeds of the front wheels and the rear wheels is a predetermined value or more based on a signal from the wheel speed detecting means for detecting the wheel speeds of the front wheels and the rear wheels. The auxiliary brake control device for a vehicle according to claim 1, which is configured to determine that