JP2000043702A - Braking control device for connected vehicles - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the braking control device of a combination vehicle which can restrain the unstable behavoir such as a trailer swing, even when the trailer not equipped with ABS unit is towed. SOLUTION: This braking control device equipped on a tractor is provided with a pressure adjust valve which can adjust a trailer indication pressure and ECU for controlling its operation. When a braking force is generated on a trailer wheel, the operation of the pressure adjust valve is controlled by ECU and the indication pressure for the brake chamber of the trailer wheel is held to a lower limit value P1 periodically. Therefore, the grip of the wheel is recovered in the exhaust time T0 and the continuous lock of the trailer wheel is dissolved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a braking control device for a connected vehicle for controlling a braking force of a trailer wheel during braking.

[0002]

2. Description of the Related Art When a wheel locks during braking of a vehicle, the vehicle skids and its running stability is extremely impaired. In recent years, many vehicles have been equipped with a known anti-skid brake system (ABS) to prevent such wheel lock.

[0003]

However, not all existing vehicles are equipped with ABS.
In particular, trailers that are not yet equipped with ABS are often used for coupled vehicles.

When a trailer without such an ABS is towed by a tractor, for example, if the trailer wheels are locked during braking during turning, a so-called trailing wing phenomenon may be caused.

[0005] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a brake control device for a connected vehicle that can prevent wheel lock during braking even if the trailer is not equipped with an ABS. Is to do.

[0006]

SUMMARY OF THE INVENTION The above object is achieved by the present invention.
It is provided with braking force adjusting means and control means. Among these, the braking force adjusting means can adjust the braking force generated on the trailer wheels independently of the braking operation by the driver. Further, the control means controls the operation of the braking force adjustment means to perform a braking force control for periodically removing the braking force generated on the trailer wheels when the vehicle is braking.

According to the above-described brake control apparatus for a connected vehicle, the gripping force of the wheel is recovered while the braking force of the trailer wheel is periodically removed during braking of the vehicle, so that the continuous braking force is provided. The wheels do not lock. In this case, the braking of the vehicle may be performed by the driver's braking operation, or the vehicle speed and the lateral acceleration may exceed the allowable values by detecting the traveling state of the vehicle, regardless of the driver's intentional operation. It may be automatically performed in conjunction with vehicle behavior control such as automatic deceleration control that automatically generates a braking force on wheels so that there is no braking force.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, there is shown a schematic configuration of a tractor 1 equipped with a brake control device according to one embodiment.

The tractor 1 of the connected vehicle is equipped with an air brake system constituted by connecting individual air brake parts organically, and is provided with air tanks 2, 4, and 6 as operating pressure sources. I have. The air brake system has front and rear service brake paths 8 and 10 for tractor wheels, and has a service brake path 12 for trailer wheels (not shown).
Further, the air brake system includes an independent brake path 1 independent of the service brake paths 8, 10, and 12 described above.
4, 16, and 18. Hereinafter, each will be described in detail. The front service brake path 8 extracts the air pressure of the air tank 2 through the brake valve 20 and supplies the air pressure to the front brake path 24 via the double check valve 22. The rear service brake path 10 extracts the air pressure of the air tank 4 through the relay valve 26 and supplies the air pressure to the rear brake path 30 through the double check valve 28. The relay valve 26 receives a signal pressure from the brake valve 20 through a pilot pressure path 32.

Further, a service brake path 1 for a trailer is provided.
2 is an air tank 6 through a dual relay valve 34.
Is supplied to the brake hose 38 via the double check valve 36. The brake hose 38 is connected to a brake coupling of a trailer (not shown). The relay valve 34 receives a signal pressure from the brake valve 20 via the pilot pressure paths 40 and 42.

On the other hand, the independent brake path 14 takes out the air pressure of the air tank 2 through the air supply valve 44 and supplies the air pressure to the front brake path 24 via the double check valve 22. In addition, the independent brake path 16 takes out the air pressure of the air tank 4 through the air supply valve 46 and supplies the air pressure to the rear brake path 30 via the double check valve 28.
To supply.

In addition, an independent brake path 18 for the trailer
Takes out the air pressure of the air tank 6 through the air supply valve 48 and supplies the air pressure to the brake hose 38 via the double check valve 36. The above-described air supply valve 4
Each of 4, 46 and 48 is constituted by a solenoid on-off valve.

The above-described front brake path 24 and rear brake path 30 are respectively connected to a brake chamber 50.
The front and rear brake paths 24, 30 are respectively connected to the pressure regulating valve 5 as shown in FIG.
2, 54 are interposed. A pressure adjusting valve 56 is also interposed between the outlet port of the double check valve 36 and the brake hose 38. Each of these pressure regulating valves 52, 54, 56 is composed of a solenoid switching valve, and each of the pressure regulating valves 52, 54, 56 has a normal position for ventilating the inserted path, and
The position between an operation position where the downstream pressure connected to the brake chamber 50 is released to the atmosphere and an operation position where the supply air pressure from each of the air tanks 2, 4, and 6 is shut off and the pressure in the brake chamber 50 is maintained. Can be switched.

The tractor 1 is provided with respective air supply valves 44, 46, 48.
And an electronic control unit (ECU) 58 for controlling the operation of each pressure regulating valve 52, 54, 56,
Individual air supply valves 44, 46, 48 and pressure regulating valves 52, 5
The ECUs 4 and 56 are electrically connected to the ECU 58.

In the air brake system shown in FIG. 1, each of the brake chambers 50 is provided with a brake air pressure sensor 70 for detecting a brake air pressure. The brake valve 20 is provided with a depressed air pressure sensor 72 for detecting an outlet air pressure corresponding to the depressed amount of the brake pedal.
Has a trailer side brake path (not shown)
A trailer air pressure sensor 74 for detecting an outlet air pressure supplied to the air conditioner is provided. The relay valve 26 (with LSV) is provided with an air pressure sensor 76 for detecting the outlet air pressure. Each of these pressure sensors outputs a signal to the ECU 58.

The pressure control valves 52, 54,
The operation control of 56 is performed by controlling each of the air tanks 2 when braking the vehicle.
Within the range up to the air pressure taken out from 4, 6
The magnitude of the air pressure in each of the brake paths 24, 30 and the brake hose 38 can be adjusted. Accordingly, such operation control of the pressure adjusting valves 52, 54, 56 can adjust the braking force of each wheel of the tractor and the trailer independently of the braking operation by the driver (braking force adjusting means).

The air brake system shown in FIG. 1 uses a service brake path 1 when a trailer is connected to a tractor 1 and towed.
Brake air pressure can be supplied to the brake hose 38 from two systems including the independent brake path 18 and the independent brake path 18 to generate braking force on the trailer wheels.

That is, when the driver depresses the brake pedal to perform a braking operation, an air pressure corresponding to the depressed amount is supplied from the service brake path 12.
The supply air pressure is supplied into a brake chamber of a trailer (not shown), and a braking force corresponding to the supply air pressure is generated on the trailer wheels.

On the other hand, separately from the braking operation by the driver, the ECU
When the air supply valve 48 is opened by the operation signal of 58, air pressure is automatically supplied from the independent brake path 18 through the air supply valve 48. In this case, the brake hose 38
Can be adjusted by operating the pressure adjusting valve 56 described above. That is, the ECU 58 adjusts the magnitude of the air pressure supplied into the brake hose 38 by switching and controlling the position of the pressure adjusting valve 56 together with the air supply valve 48.

The automatic supply and adjustment of the brake air pressure by the ECU 58 is performed, for example, when executing an automatic deceleration control as a known vehicle behavior control. More specifically, the tractor 1 is equipped with a plurality of sensors that detect a running state and output a signal, and the automatic deceleration control is performed by evaluating running state information obtained from detection signals from these sensors. . The sensors include a steering angle sensor 60, a wheel speed sensor 62, a yaw rate sensor 64, and a longitudinal acceleration sensor 6.
6 and a lateral acceleration sensor 68. These sensors are:
Each outputs a detection signal to the ECU 58.

Referring to FIG. 2, there is shown a block diagram showing an electrical connection relationship for the ECU 58 to execute the automatic deceleration control. As illustrated, each of the various sensors described above is electrically connected to the ECU 58, and outputs a detection signal to the ECU 58.

The ECU 58 can process the sensor signals from these various sensors to obtain the traveling state information of the vehicle. For example, it is information such as the front wheel steering angle δ, the vehicle speed V, the actual yaw rate γ of the tractor 1, the longitudinal acceleration Gx, and the lateral acceleration Gy. Then, the ECU 58 evaluates the information on the traveling state, and automatically generates a braking force on each wheel so that the vehicle speed V and the lateral acceleration Gy do not exceed predetermined allowable values, thereby causing the vehicle to drift out or spin. , Rollover, etc. are prevented. At this time, the ECU 58 obtains a deceleration required to limit the actual vehicle speed V and the lateral acceleration Gy to the allowable value or less when the vehicle turns, and when the obtained deceleration exceeds a predetermined threshold, the automatic deceleration control is performed. Execute Note that the ECU 5
Reference numeral 8 indicates an allowable value of the vehicle speed V, that is, a safe vehicle speed, according to the estimated turning radius and the road surface friction coefficient, and stores a predetermined allowable value for the lateral acceleration Gy.

A known ABS function can be applied to the tractor wheels at the time of automatic braking by the above-described vehicle behavior control or at the time of braking by a driver's braking operation. That is, based on the connection shown in FIG. 2, for the tractor wheels, the ABS control center is programmed in the ECU 58, so that the wheel speed of each wheel (FR, FL, RR, RL) is fed back to the control system during braking to adjust the pressure. By operating the valves 52 and 54, locking of the tractor wheels can be suppressed. The accurate operation of the pressure adjusting valves 52 and 54 can be controlled by feeding back the actual air pressure detected by each air pressure sensor 70.

On the other hand, when the trailer is an existing trailer and is connected to the air brake system of the tractor 1 only by the brake hose 38, the feedback for the ABS control as described above is performed for the trailer wheels. Loops cannot be constructed. Therefore, the ECU 5
Numeral 8 executes the braking force control of the trailer wheels in the following procedure when the vehicle is braked, and deals with a trailer not equipped with ABS.

Referring to FIG. 3, when braking the connected vehicle, E
The flowchart of the braking force control routine executed by the CU 58 is shown.

In step S10, it is determined whether or not the trailer wheel is being braked. This determination is true (Yes) in both cases of the braking operation by the driver and the automatic deceleration by the behavior control. In any of these cases, as soon as braking of the trailer wheels is started, step S12 is executed.
Proceed to. In the following embodiment, a case will be described in which braking is automatically performed in conjunction with automatic deceleration control.

In the next step S12, the supply / discharge time of the brake air pressure to the brake system of the trailer wheel is determined. The air supply time is a time for supplying air pressure to the brake chamber of the trailer wheel, while the exhaust time is a time for discharging the brake air pressure. Specifically, the ECU 58 controls the command pressure on the brake system of the trailer at a predetermined cycle as described later, and keeps the command pressure equal to or lower than the braking force invalid air pressure within the exhaust time. The control for removing the braking force of the wheel is executed.

Such a determination of the supply / exhaust time can be performed, for example, by the following method. The ECU 58 stores data on a preset supply / exhaust time, and determines the supply / exhaust time according to the stored data.

It should be noted that the supply / exhaust time can be calculated and determined. For example, the calculation may be performed based on the magnitude of the target command pressure accompanying the automatic deceleration control, and the supply / exhaust time may be varied according to the magnitude of the target pressure.

In the next step S14, the operation of the pressure regulating valve 56 is actually controlled according to the determined supply / exhaust time. Specifically, during the air supply time determined in step S12, the operation of the pressure regulating valve 56 is controlled in accordance with the actual trailer instruction pressure, and on the other hand, it is switched to the atmosphere open position during the exhaust time.

Referring to FIG. 4, there is shown a graph showing the relationship between the air supply / exhaust time and the indicated trailer pressure. As shown, from the time t ₀ as the start of braking, until time t ₂ when the supply time T _i has elapsed, the indicated pressure with the automatic deceleration control is supplied to the brake chambers of the trailer wheels.

It should be noted that, in this embodiment, when the air supply time is early,
Time t₀~ T₁Until the indicated pressure reaches the maximum value P₀Held in
ing. Thus, the initial air supply time T_pOf the indicated pressure
Large value P ₀The air tank 6 and the trailer
Considering the length of the piping to the rake chamber,
To compensate for the response delay required to raise the rake air pressure
It is.

After the above-mentioned time T _p has elapsed, the time t ₁ to t ₁
between t _2, actuating the pressure regulating valve 56 in accordance with an instruction pressure shown. Then, the exhaust time T _o from time t ₂ to time t _3, the air pressure is discharged, the trailer indicated pressure is held at the lower limit value P _1. The lower limit P ₁ is set under the air pressure or the braking force of the trailer wheels actually becomes invalid as described above. In FIG. 4, the command pressure when such control of the command pressure is not performed is indicated by a two-dot chain line.

The ECU58 the time of braking of the trailer wheels to repeat the indicated pressure control to such a supply and exhaust time T _p, T _o one period. Therefore, the exhaust time T _o is the braking force of the trailer wheels are periodically removed, the gripping force of the wheels is restored during this period.

According to the braking control device of the embodiment described above,
When the braking force is applied to the trailer wheels in conjunction with the automatic deceleration control, the braking force is periodically removed, so even if the trailer wheels tend to lock, the wheel grip force is recovered periodically. I do. Therefore, the tendency of the trailer wheel to be locked continuously for a long time can be eliminated, and the occurrence of the trailing wing phenomenon or the like can be reliably prevented.

On the other hand, during the above-mentioned air supply time, the automatic deceleration system
Fully exerts the automatic braking force that accompanies the vehicle
Greatly contributes to Moreover, when air is supplied as in this embodiment,
Interval T _iWithin the initial air supply time T_pIs set,
During this time, the air pressure in the brake chamber
Response delay of braking force generation is effectively compensated for
You.

In the above-described embodiment, the description has been given of the case of the braking accompanying the automatic deceleration control. However, the same applies to the case where the driver depresses the brake pedal and the case where the trailer brake (not shown) is operated. By periodically changing the indicated pressure according to the supplied air supply / exhaust time, locking of the wheels can be prevented.

Further, a method of determining the supply and exhaust time T _i, T _o is arbitrary changed, can also be the period variable.

In addition, the specific configuration of the air brake system shown in FIG. 1 can be variously changed, and is not limited to the air brake system alone.

[0040]

As described above, according to the brake control apparatus for a connected vehicle according to the first aspect, the trailer wheels are reliably prevented from locking for a long time, and the running stability of the connected vehicle is improved. Greatly improved. In addition, since the control can be performed without adding a special unit to the existing trailer, the effective use of social capital is promoted.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a configuration of a tractor equipped with a braking control device according to one embodiment.

FIG. 2 is a block diagram showing a control concept of the braking control device of FIG. 1;

FIG. 3 is a flowchart showing a braking force control routine of a trailer wheel.

FIG. 4 is a graph showing a time change of a trailer command pressure obtained by executing the control routine of FIG. 3;

[Explanation of symbols]

 1 Tractor 52, 54, 56 Pressure adjusting valve (braking force adjusting means) 58 ECU (control means)

Claims (1)

[Claims] An articulated vehicle having a tractor and a trailer connected to the tractor and towed operates independently of a braking operation by a driver to adjust a braking force generated on a trailer wheel. A braking force adjusting means provided; and a control means for controlling an operation of the braking force adjusting means to periodically remove a braking force generated on the trailer wheels when the vehicle is braked. Vehicle braking control device.