JPS63251357A - Braking force retention device - Google Patents

Abstract

PURPOSE:To enable an automobile to make a smooth start by retaining and releasing the braking force as the actual engine speed change rate is compared with a criterion which is the characteristic map of a travel distance of an accelerator pedal and the engine speed change rate at each gear stage. CONSTITUTION:The gear stage indicated by an engine speed sensor 19a, an accelerator sensor 20a and a transmission actuator 13 that works as a gear position sensor, and the engine speed change rate of a braking force releasing criterion corresponding to the output of the travel distance of the accelerator sensor 20a are to be read. Namely, the actual engine speed change rate obtained from a sensor 19a is to be compared with the engine speed change rate corresponding to the travel distance of an accelerator pedal at a recognized gear stage under the condition while an accelerator pedal 20 is stepped on by the output of the accelerator sensor 20a, the output of an automobile speed sensor 16 is showing that the automobile is at a stop and an accelerator lever 17 is not in a neutral position by a gear position sensor recognizing the gear stage. When the actual change rate falls below the change rate criterion, a check valve 3 to release the braking force.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a braking force holding device, and more particularly to a device for smoothly and safely releasing the braking force of a vehicle.

[Conventional technology]

When starting a vehicle stopped on a road, in conventional vehicles, the driver uses the parking brake (handbrake) with one hand to apply braking force to the vehicle and keep it at a stop, while gradually engaging the clutch. Depress the accelerator pedal. During this time, the parking brake is gradually loosened.

However, since complicated operations are required while coordinating the brake and accelerator, skill is required to perform a smooth start, which may result in so-called engine stalling or the vehicle moving backwards.

Therefore, the present applicant previously filed Japanese Patent Application No. 117483/1983 (
Japanese Patent Application Laid-Open No. 11719/1983 proposes an electronic automatic transmission with a braking force retention device. With this device,
A control electromagnetic check valve is provided between the mask cylinder and the wheel cylinder that are linked to the brake pedal, and in order to enable this electromagnetic check valve to smoothly start from a stopped state on the road, the accelerator pedal sensor and clutch stroke sensor, engine rotation sensor, brake pedal switch,
Input the output signals from the gear position switch, select position switch and vehicle speed sensor to the electronic control unit (ECU),
Based on these input signals, the electronic control unit determines: ■The gear select position is not neutral; ■The vehicle speed is "o"; ■The end of gear shifting; ■The engine is in idle condition; ■The foot brake is depressed; ■The accelerator is released. , and ■The clutch has a retention amount less than the half-clutch state (
clutch disengagement), and energizes the electromagnetic check valve to generate braking force to the wheel cylinder only when all of these conditions (1) to (2) are satisfied.

In addition, the braking force to the wheel cylinders is released when ■ the engagement amount of the clutch becomes larger than the half-clutch state (clutch engagement), or ■ when the gear is in the neutral position, or when the [phase] vehicle speed is the set vehicle speed. The electronic control unit determines that the accelerator pedal is being depressed at the above times and deenergizes the electromagnetic check valve.

[Problem that the invention seeks to solve]

The above-mentioned Japanese Patent Application No. 117483/1983
The braking force holding device disclosed in Japanese Patent No. 1719 is capable of synchronously controlling the operation of the electromagnetic check valve and the friction clutch so that the braking force is held by the clutch fluid actuator until the clutch is engaged. It is especially excellent in that it allows smooth starting on a boarding road without requiring any skill, but since the brake check valve is always released at a fixed clutch engagement position, it is possible to easily start the vehicle on a loaded road. Depending on the condition or road gradient, the braking force may be released too quickly and the vehicle may move backwards, or the braking force may be released too late and the vehicle may start suddenly.

Therefore, an object of the present invention is to provide a device that can always release the braking force at an appropriate timing, thereby facilitating a smooth start.

[Means for solving problems]

As a means for solving the above problems, the braking force holding device according to the present invention includes an engine rotation speed sensor, an accelerator sensor, a gear position sensor, a vehicle speed sensor, and a gear position indicated by the gear position sensor in a stopped state. Then, read out the rate of change in engine speed based on the braking force release standard according to the pedal depression output of the accelerator sensor, and use this to operate the braking electromagnetic check valve when the rate of change in the actual speed obtained from the engine speed sensor is lower than the rate of change in engine speed. and control means for deenergizing.

[For production]

The braking force retention device of the present invention focuses on the fact that the clutch engagement amount can be detected as a change in engine speed, and the gear position sensor recognizes the gear stage so that the select lever is not in the neutral position. When the vehicle speed sensor output indicates a stopped state and the accelerator pedal is depressed based on the accelerator sensor output, the control means sets the rate of change in engine speed corresponding to the amount of accelerator depression for the recognized gear as a criterion for releasing the braking force. Read it as a value and compare it with the actual rate of change in engine speed obtained from the engine speed sensor, and when the actual rate of change is less than the reference rate of change read out, the electromagnetic check valve for braking is deenergized. Release braking force.

〔Example〕

An embodiment of the braking force holding device according to the present invention will be described below.

FIG. 1 is a diagram showing the hardware configuration of an embodiment of the braking force holding device according to the present invention, in which 1 is a brake pedal;
is a brake pedal switch provided on brake pedal 1, 2 is a master cylinder, 3 is a braking electromagnetic check valve, 4 is a brake pedal switch provided on brake pedal 1;
5 is a wheel cylinder, and 5 is a solenoid, which constitute a brake actuating device (braking device) 8. 7 is a fluid pressure source, 8 is a tank, 9 is a solenoid valve for a clutch actuator, 10 is a tarlatch actuator, 10a is a clutch stroke sensor, and 11 is a friction clutch, which constitute a clutch actuating device B. 12 is a transmission, 12a is a transmission output shaft whose output is transmitted to differential gear 1
4 to the wheels 15. Reference numeral 19 denotes an engine, and when the accelerator pedal 20 is depressed, the opening degree of a throttle valve 19b is controlled and the rotation speed is controlled.

6 is an electronic control unit (ECU), which outputs an output signal from a vehicle speed sensor 16 provided on the output shaft 12a side of the transmission 12, an output signal indicating the gear stage from a transmission actuator 13 as a gear position sensor, and a select signal. An output signal from the select position switch 18 of the lever 17, an output signal from the engine rotation speed sensor 19a provided in the engine 19,
From the output signal from the accelerator pedal sensor 20a provided on the accelerator pedal 20, the output signal from the brake pedal switch 1a, the output signal from the parking brake switch 31 provided on the parking brake 30, and the output signal from the clutch stroke sensor 10a. By inputting output signals from various sensors and switches, and processing those signals, control signals are sent to the solenoid 5.
This control signal is used to control the control solenoid valve check valve 3.
The control device A is configured to operate so that the braking force of the control device A can be maintained.

Next, the operation of maintaining braking force in the embodiment of the present invention shown in FIG. 1 will be explained. However, regarding the braking force holding operation, as mentioned above, Japanese Patent Application No. 117483/1983
Since this operation is known from the braking force holding device disclosed in Japanese Patent No. 11719, etc., it will be briefly explained.

(1) The select position of the select lever 17 is other than the neutral position, (2) The vehicle speed is "'0" according to the output of the vehicle speed sensor 16 and the vehicle is stopped, (3) The gear is changed according to the output of the shift actuator 13. (4) the engine is in a rotating (idle) state according to the output of the engine speed sensor 19a, and (5) the accelerator pedal sensor 20a is in the lowest position of the range corresponding to the select position of the select lever 17. The output indicates that the accelerator pedal 20 is not depressed, (6) the output of the brake pedal switch 1a indicates that the brake pedal 1 is depressed, and (7) the clutch stroke sensor 10a
When the clutch 11 is engaged less than the half-clutch state by the output of
The braking force is maintained by preventing the control oil from returning to the mask cylinder 2.

FIG. 2 shows another embodiment of the braking force holding device according to the present invention. This embodiment is a configuration diagram applied to a large vehicle using pneumatic control. The difference from FIG. The actuating device A is provided with a depression amount detector 1b attached to the brake pedal 1, an air tank 40, and an air master 41 instead of the master cylinder, and starting from the depression amount detector 1b, the air tank 40
Additionally, an air pressure control route is added to the wheel cylinder 4 via the air master 41.

FIG. 3 is a diagram mainly showing a flowchart for releasing the braking force among the programs stored in advance in the electronic control device 6. The operation of the braking force holding device of the present invention will be explained with reference to this flowchart. .

First, the vehicle speed signal is sent from the vehicle speed sensor 16, the engine rotation signal from the engine rotation speed sensor 19a, the parking brake signal from the parking brake switch 31, the accelerator pedal depression amount signal from the accelerator pedal sensor 20a, and the select lever signal from the select position switch 18. Each is read (steps 81 to S5 in FIG. 3).

Next, the gear stage is recognized from the output signal of the transmission actuator 13 (step S6), and the rate of change n of the engine speed is calculated from the engine speed data obtained in step S2 (step S7). It is determined from the engine rotation speed of the current cycle and the engine rotation speed of the previous cycle of the program shown in FIG. 3, which is started at time intervals. The braking force is maintained and released based on the above data.

Braking force holding mode I (1) The select lever position is determined to be neutral in step S8, (2) Parking brake switch 31 is determined in step S9.
(3) It is determined in step SIO that the vehicle is in a stopped state when the vehicle speed is less than a predetermined value of 5 PDI, and (4) Step S
It is determined that the accelerator pedal 20 is not depressed at 11, and when all of the following conditions are satisfied, the check valve 3 is kept energized (step 316). This is because the braking force is still required. However, in step S8, the transmission actuator 13
It is also possible to automatically determine that the select lever 17 is not in neutral by recognizing the gear position (step S6).

Further, step S9 is not essential to the present invention.

The reason is that the parking brake generates braking force in a completely different system, so when the driver pulls the parking brake halfway, there is no risk that the already applied brake pressure will drop due to valve leaks and the braking condition will collapse. That's because it's common.

Braking force holding mode ■ (]) Mode I conditions (]) to (3) are common, (2
) It is determined in step 311 that the accelerator pedal 20 is depressed; (3) In step SL2, a characteristic map of the amount of accelerator depression and the rate of change in engine speed already determined for each gear stage (see FIG. 4) is determined. ) is stored in a memory (not shown), an appropriate map is selected according to the gear already determined in step S6, and further, in step S13, the braking force corresponding to the accelerator depression amount determined in step S4 is determined. When the cancellation standard engine speed change rate ΔNi is calculated from the map, it is determined in step SI4 that the actual engine speed change rate n calculated in step S7 is n>ΔNj. If the condition is satisfied, the braking force is maintained with the check valve 3 energized (step 816). This is because even if the accelerator is depressed, the clutch engagement amount is still increasing, and it is determined that it is still too early to release the braking force to start on the uphill road.

°1 Power release mode■ (1) In step S8, it is determined that the select lever position is not neutral, (2) In step S9, the parking brake switch 31
is determined to be on and the parking brake 30 is pulled, and (3) it is determined in step SIO that the vehicle speed is higher than a predetermined value of 5 PDI and is not in a stopped state. Valve 3 is deenergized to release the braking force (step 515). This is because it is still determined that the braking force request state has been released.

Braking force residual mode■ Conditions for holding mode■ (condition (3) among 11 to (3))
In step S14, if the actual engine speed change rate n does not satisfy the determination in step S14 that n≦8i, the check valve 3 is deenergized and the braking force is released. (step 515).

This is because it is determined that the increase in the clutch engagement amount has decreased and engagement of the clutch has been completed, and that it is desirable to release the braking force in order to start the vehicle on the uphill road.

In the above explanation, the rate of change in the engine speed can be considered to be both positive and negative, but in the present invention, the rate of change in the engine speed is determined in the process of increasing the engagement amount of the clutch in relation to releasing the braking force. Since this has been introduced, only negative rates of change are used, and therefore characteristic maps prepared in advance only need to be those with negative rates of change.

〔Effect of the invention〕

As described above, in the braking force holding device of the present invention, the actual engine speed change rate is calculated based on the engine speed change rate in the characteristic map of the accelerator depression amount and engine speed change rate for each gear that has already been determined. Since braking force is maintained and released by comparing the braking force with Can be done.

[Brief explanation of the drawing]

FIG. 1 is a hardware configuration diagram showing one embodiment of the braking force retention device according to the present invention; FIG. 2 is a hardware configuration diagram showing another application example of the braking force retention device according to the present invention; 3 is a flowchart diagram mainly for executing the release of braking force among the programs stored in the electronic control device used in the present invention, and FIG. 4 is a flowchart diagram of the program stored in the electronic control device used in the present invention A diagram showing a characteristic map of the amount of accelerator depression and engine speed change rate. In the figure, 19 is the engine, 19a is the engine speed sensor, 20a is the accelerator sensor, 12 is the transmission, and 13
1 shows a transmission actuator as a gear position sensor, 16 a vehicle speed sensor, 6 an electronic control device, and 3 an electromagnetic check valve for braking. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (3)

[Claims] (1) An engine speed sensor, an accelerator sensor, a gear position sensor, a vehicle speed sensor, and an engine with a braking force release standard according to the gear position indicated by the gear position sensor in a stopped state and the pedal depression output of the accelerator sensor. The engine is characterized by comprising a control means for reading out the rate of change in the engine speed and deenergizing the braking electromagnetic check valve when the rate of change in the engine speed becomes lower than the rate of change in the actual engine speed obtained from the engine speed sensor. Braking force retention device. (2) The braking force according to claim 1, wherein the control means includes a memory that stores a map of a rate of change in engine speed with respect to the amount of accelerator depression according to the gear position indicated by the gear position sensor. holding device. (3) The braking force holding device according to claim 1 or 2, wherein the control means determines that the gear position indicated by the gear position sensor is not in a neutral state.