JPH0228041A - Braking force holding device - Google Patents

Abstract

PURPOSE:To enable safe and comfortable starting to be attained by deenergizing a braking force holding electromagnetic check valve to release braking force, when an engine speed reaches a speed in which a predetermined value is added to the engine speed in its conversion from an idle condition to a non-idle condition. CONSTITUTION:In the case of a controller 12 which inputs each output signal from an idle switch 2, brake switch 4, engine speed sensor 9, neutral switch 10 and a car speed sensor 11, when a vehicle is detected for its braking condition, a braking force holding electromagnetic check valve 7, provided interposing in a brake fluid pressure pipe 6, is energized and closed. This valve 7 holds a pressure of brake fluid in a wheel cylinder 8 increased by step-in action of a brake pedal 3. While in this braking force holding condition, when an engine speed reaches a speed in which a predetermined value is added to the engine speed in its conversion from an idle condition to a non-idle condition, the controller deenergizes the electromagnetic check valve 7, performing a control so as to release braking force from its holding.

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a braking force holding device, and more particularly to a device for releasing the held braking force under certain conditions.

[Conventional technology]

Braking force retention devices that release the retained braking force under certain conditions are conventionally disclosed in Japanese Patent Laid-Open Nos. 59-143746 and 61-200054. First, the device disclosed in Japanese Patent Application Laid-Open No. 59-143746 uses an automated parking brake device to maintain braking force, and when the brake pedal is stepped on to stop the vehicle, the controller sends a signal to the electric motor. The parking brake cable is wound up to activate the brake and generate braking force. This state is maintained until the braking force is released. In order to detect the release state of this braking force, the engine speed required when the vehicle starts is determined and stored in advance according to the road surface gradient as shown in Fig. 4, and when the accelerator pedal is depressed and the brake pedal is When the parking brake cable is released and the engine speed reaches a speed corresponding to the current road slope determined by the slope sensor, the parking brake cable that was wound around the electric motor is returned to its original position and the braking force is released. Next, in the device disclosed in JP-A No. 61-200054, braking force is maintained by closing an electromagnetic check valve installed in the middle of the hydraulic piping that communicates the master cylinder of the main brake device with the wheel cylinder. The braking force is released by opening this reverse valve. To briefly explain this based on FIG. 1, first, when the vehicle stops on a hill, the brake switch 4 is on, and when the vehicle speed output from the vehicle speed sensor 11 becomes zero, the controller 12 operates the electromagnetic check valve. (S) 7 is energized and closed, and the communication between the wheel cylinder (IIs) 8, which is in communication with the hydraulic pipe 6, and the master cylinder (MS) 5, which is engaged with the brake pedal 3, is cut off. ,
Brake oil in a wheel cylinder 8, which has become high in oil pressure when a brake pedal 3 is depressed, is not returned to a master cylinder 5 even when the brake pedal 3 is released, and high oil pressure is maintained to maintain braking force. When the vehicle starts, it is determined whether the vehicle is ready to start based on the engagement of the clutch (not shown) and the accelerator opening. When the opening exceeds the set value, it is determined that it is possible to start, the electromagnetic check valve 7 is deenergized, and the wheel cylinder 8 is activated.
The high pressure of the brake oil held inside is returned to the master cylinder 5 to release the braking force. [Problems to be Solved by the Invention] The conventional braking force holding device as described above has the following problems when releasing the braking force. First, the device disclosed in Japanese Patent Application Laid-open No. 59-143746 sets the required engine speed at the time of releasing the braking force as a main condition for releasing the braking force, as shown by the solid line in Fig. 4, in accordance with the road surface slope. Furthermore, when the idle speed increases, such as when the air conditioner is activated, the set speed is shifted to the high speed side as shown by the broken line in FIG. This means that if the engine speed required to release the braking force is only in the case shown by the solid line in Figure 4, the engine speed will quickly reach the required engine speed on the solid line due to the increase in engine speed due to the increase in idle speed when the air conditioner is activated. This is to prevent the braking force from being released early if the brake force is reached. On the other hand, the engine speed during idling fluctuates as shown by the curve in Fig. 5 depending on the operating state of the vehicle's electrical loads, etc., but in the device disclosed in JP-A-59-143746, the braking force is released. The required engine rotation speed at the time is set at a constant rotation speed that does not take into account the above-mentioned idle rotation speed dispersion, and the setting value when increasing the idle rotation speed is also a high rotation speed as shown by the broken line and the solid line setting value in Figure 4. It is simply a parallel movement to the side. Therefore, when the idle speed is high, when the braking force is released, the engine speed will reach the set value quickly (especially when the idle speed is increased when the engine is cold), and the engine speed will reach the set value quickly, which is necessary for starting. Since the braking force is released before engine output is obtained, the insufficient engine output may cause the engine to stall or the vehicle to backtrack when starting from a hill. On the other hand, when the idle speed is low, if the braking force is released, the engine output at the engine speed when the braking force is released is too much than the output required to start the vehicle, causing the vehicle to start. This causes problems such as making the driver feel tired and making it difficult to move the vehicle even slightly. Also, in the device disclosed in Japanese Patent Application Laid-Open No. 61-200054, the main condition for releasing the braking force is that the accelerator opening (or engine speed) exceeds a reference value, but the setting of this reference value is also As in JP-A-59-143746, the value is set to a constant value, so there is the same problem as above. SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a braking/force holding device that can ensure smooth vehicle start and operability when the braking force of the vehicle is released. [Means for Solving the Problems] As a means for achieving the above object, the braking force retention device according to the present invention includes an idle state detection means, an engine rotation speed sensor, and an electromagnetic check valve for braking force retention. and when the engine rotational speed reaches an engine rotational speed obtained by adding a predetermined value to the engine rotational speed at the time of transition from the idle state to the non-idle state detected by the detection means, the check valve is deenergized. and control means for releasing the braking force. [Function] In the present invention, the engine speed is determined by adding a predetermined value to the engine speed read from the engine speed sensor when the engine changes from the idle speed state detected by the idle state detection means to the non-idle speed state. When the current engine speed becomes higher than the current engine speed, the braking force retention solenoid valve is deenergized and the retained braking force is released. As a result, the braking force can be released at an engine speed commensurate with the idling speed when the vehicle starts. [Example] Hereinafter, an example of the braking force holding device according to the present invention will be described. FIG. 1 is a configuration diagram of an embodiment of the braking force holding device according to the present invention. As mentioned in the explanation of the conventional example above, ■ is turned on when the accelerator pedal is pressed, and 2 is turned on when the accelerator pedal L is pressed. Idle switch as idle state detection means, 3
is a brake pedal, 4 is a brake switch that is turned on when the brake pedal 3 is depressed, 5 is a master cylinder (MS) that is engaged with the brake pedal 3, 6 is a brake hydraulic piping, and 7 is connected to the mask cylinder 5 by piping 6. Communicating electromagnetic check valve (S) for retaining braking force, 8 is check valve 7
and a wheel cylinder (H5) which is connected through piping 6 to generate braking force, 9 is an engine rotation speed sensor, 10 is a neutral switch that is turned on when the gear or selector (not shown) is in neutral position, and 11 is a vehicle stop switch. A vehicle speed sensor 12 is used for checking, and a controller 12 is a control means that calculates signals read from the idle switch 2 and the engine speed sensor 9, deenergizes the electromagnetic check valve 7, and releases the braking force. FIG. 2 is a flowchart of a program for releasing the braking force that is stored and executed in the controller shown in FIG. 1, and the operation of the embodiment shown in FIG. 1 will be explained based on this flowchart. First, the controller 12 detects the braking state of the vehicle based on the outputs of the idle switch 2, brake switch 4, vehicle speed sensor 11, and neutral switch 10, and energizes the electromagnetic check valve 7. At this time, the braking force generated by the high-pressure brake oil during wheel cylinder operation, which has increased due to the depression of the brake pedal 3, is maintained by the electromagnetic check valve 7 being energized (turned on). These operations are not shown but are well known. In such a braking force holding state, the controller 12
checks whether the vehicle is ready to start (
Step 5ISS2 in FIG. 2). That is, in step S1, neutral switch 1
0 is on and the engine is not rotating in step S2, the vehicle determines that another brake operation such as the handbrake is sufficient, and the electromagnetic check valve 7 is turned off (step 36) and the above procedure is performed. The braking force is released, but
If the neutral switch 10 is off and the engine is rotating, it is expected that the vehicle will start, so it is next necessary to determine whether the engine is in an idling state or a non-idling state using the idle switch 2 (step S3).
), when it is determined that the engine is idling, the latest engine speed N1 is manually input from the engine speed sensor 9 and stored in a memory (not shown) in the controller 12 (step S4). Then, as a result of the driver pressing the accelerator pedal,
If it is determined in step S3 that the idle switch 2 is on, the engine rotational speed becomes the preset engine rotational speed ΔN, which is the latest idle rotational speed N1 stored in the memory in step S4. (This is the margin rotation speed determined in advance through experiments, etc., which is necessary for the engine output to perform a smooth start from the idle state) It is determined whether or not the rotation speed has been reached. If it is determined that this is the case, the electromagnetic reverse valve 7 is turned off, the high pressure held in the wheel cylinder 8 is released, the braking force is released, and this program is terminated. Here, steps S3 to S36 will be explained chronologically based on FIG. 3. While the idle switch 2 is off (step S33), the latest engine speed on the idle speed curve shown in FIG. is always stored in the memory (step S4), and the engine rotation speed Nl at the time when the idle switch 2 is turned on (point A in Fig. 3)
is maintained, and when the engine speed reaches the speed N1 + ΔNo, which is the sum of this speed N1 and a preset engine speed ΔNo (point B in Figure 3), the electromagnetic check valve is activated to release the braking force. 7 is off. In the above embodiment, an idle switch is used as the idle state detection means, but it goes without saying that the same operation can be achieved by using an idle sensor and comparing it with a reference value. [Effects of the Invention] As described above, in the braking force holding device of the present invention, the engine rotation speed set as the braking force release condition is not set to a constant value, but when the vehicle starts (when changing from an idling state to a non-idling state). ) is detected, and the engine rotation speed Δ, which is preset in order to smoothly start the vehicle, is detected.
Since the braking force is released based on the engine speed plus the engine speed, the engine speed when the braking force is released always matches the starting condition of the vehicle. It is possible to eliminate backtracking and sudden starts of the vehicle, and it is also possible to easily move the vehicle a little, resulting in the effect that the vehicle can be started safely and comfortably.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of a braking force holding device according to the present invention, FIG. 2 is a flowchart of a program executed by a controller used in the present invention, and FIG. Figure 4 is an explanatory diagram showing the operation of power release over time. FIG. 5 is a graph showing rocking during idle rotation. In Fig. 1, ■ is an accelerator pedal, 2 is an idle switch, 7 is an electromagnetic check valve, 9 is an engine speed sensor,
12 indicates a controller.

Claims (1)

[Claims] An idle state detection means, an engine rotation speed sensor,
The electromagnetic check valve for braking force retention and the engine rotation speed reach an engine rotation speed obtained by adding a predetermined value to the engine rotation speed at the time of transition from the idle state to the non-idle state detected by the detection means. A braking force holding device comprising: control means for deenergizing the check valve and releasing the braking force when the check valve is turned off.