JPH0584259B2 - - Google Patents

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 the boarding road,
In conventional vehicles, the driver uses the parking brake (handbrake) with one hand to apply braking force to the vehicle and keep it stationary while gradually engaging the clutch and simultaneously depressing the gas 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 has previously proposed an electronic automatic transmission device with a braking force retention device in Japanese Patent Application Laid-open No. 117483/1983 (Japanese Patent Laid-Open No. 11719/1983). In this device, a control electromagnetic check valve is installed between the master cylinder and the wheel cylinder, which are linked to the brake pedal, and the accelerator pedal The output signals from the sensor, clutch stroke sensor, engine rotation sensor, brake pedal switch, gear position switch, select position switch, and vehicle speed sensor are input to the electronic control unit (ECU), and the electronic control unit uses these input signals to determine the gear. Determines whether the select position is neutral or the clutch is engaged less than the half-clutch state, the vehicle speed is "0", the end of gear shifting, the engine's idle state, the depression of the foot brake, the opening of the accelerator, and so on. However, only when all of these conditions are satisfied, the electromagnetic check valve is energized to maintain the braking force in the wheel cylinder.

In addition, the braking force at the wheel cylinder can be released when the gear select position is not neutral and the clutch is engaged more than in the half-clutch state (clutch engaged), or when the accelerator pedal is depressed. This is done by making a determination by the electronic control unit and deenergizing the electromagnetic check valve.

[Problem that the invention seeks to solve]

The above patent application No. 117483/1983 (Japanese Patent Application No. 11719/1983)
The braking force holding device disclosed in the above publication 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. This system 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, the vehicle's Depending on the loading condition or road gradient, the braking force may be released too quickly, causing the vehicle to move backwards, or the braking force may be released too late, causing the vehicle to suddenly start.

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-mentioned problems, in the braking force holding device according to the present invention, the engine speed sensor is replaced with an accelerator sensor, a gear position sensor, a vehicle speed sensor, and the output signals of these sensors are used to control the automatic clutch plate. In the braking force holding device for an automatic transmission vehicle, the control means controls a clutch engagement amount according to a gear stage indicated by the gear position sensor in a stopped state and a depression amount output of the accelerator sensor. The braking electromagnetic non-return check reads the negative rate of change in the engine speed which indicates an increase in the engine speed and serves as a reference for releasing the braking force, and when this exceeds the negative rate of change in the actual engine speed obtained from the engine speed sensor. It is characterized by deenergizing the valve.

[Effect]

In the braking force retention device for an automatic transmission vehicle according to the present invention, we focused on the fact that the amount of engagement of the automatic clutch plate when the accelerator pedal is depressed can be detected as a change in the engine rotation speed, and the gear position sensor detects the engagement of the automatic clutch plate when the accelerator pedal is depressed. By recognizing the gear, when the select lever is not in the neutral position, the vehicle speed sensor output indicates a stopped state, and the accelerator sensor output indicates that the accelerator pedal is being depressed, the system corresponds to the amount of accelerator depression for the recognized gear. The control means reads the negative rate of change in the engine speed as an increase in the clutch engagement amount, which is the reference value for releasing the braking force, and compares it with the actual rate of change in the engine speed obtained from the engine speed sensor. When the rate of change is less than the read reference rate of change, the braking electromagnetic check valve is deenergized and the braking force is released.

〔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, 1a is a brake pedal switch provided on the brake pedal 1, 2 is a master cylinder, 3 1 is a braking electromagnetic check valve, 4 is a wheel cylinder, and 5 is a solenoid, which constitute a brake actuating device (braking device) A. 7 is a fluid pressure source, 8 is a tank, 9 is a solenoid valve for clutch actuator, 10 is a clutch actuator, 10a
1 is a clutch stroke sensor, and 11 is a friction clutch serving as an automatic clutch plate, and these constitute a clutch actuating device B. 12 is an automatic transmission; 12a is a transmission output shaft, the output of which is transmitted to wheels 15 via differential gears 14; 19 is the engine, and the accelerator pedal 2
The opening degree of the throttle valve 19b is controlled by the 0 step, and the rotational speed is controlled.

6 is an electronic control unit (ECU), and transmission 1
Vehicle speed sensor 16 provided on the output shaft 12a side of No. 2
an output signal indicating the gear stage from the transmission actuator 13 as a gear position sensor;
Select position switch 18 of select lever 17
output signal from the engine speed sensor 19a provided on the engine 19, output signal from the accelerator pedal sensor 20a provided on the accelerator pedal 20, output signal from the brake pedal switch 1a, output signal from the parking brake 30. Output signal from the provided parking brake switch 31 and clutch stroke sensor 10a
By inputting output signals from various sensors and switches, and processing these signals, a control signal is output to the solenoid 5, and 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, this braking force holding operation is known from the braking force holding device shown in Japanese Patent Application No. 58-117483 (Japanese Unexamined Patent Publication No. 60-11719) as mentioned above, so it will be briefly explained. do.

(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, and (3) The gear position is determined according to the output of the shift actuator 13. is at the lowest stage of the range corresponding to the select position of the select lever 17, (4) the engine is in a rotating (idle) state according to the output of the engine rotation speed sensor 19a, and (5) the accelerator pedal sensor 2
When the following conditions are met: the accelerator pedal 20 is not depressed due to the output of the brake pedal switch 1a, and (6) the brake pedal 1 is depressed due to the output of the brake pedal switch 1a, the electronic control device 6 switches the solenoid 5 is energized to prevent the control oil of the wheel cylinder 4 from returning to the master cylinder 2, thereby maintaining the braking force.

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 is explained with reference to this flowchart. explain.

First, the vehicle speed signal is sent to the vehicle speed sensor 16, the engine rotation signal is sent to the engine rotation speed sensor 19a, and the parking brake signal is sent to the parking brake switch 3.
1. Read the accelerator pedal depression amount signal from the accelerator pedal sensor 20a and the select lever signal from the select position switch 18 (steps S1 to S5 in FIG. 3).

Next, the gear position 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).
This 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 a set time period. The braking force is maintained and released based on the above data.

Braking force holding mode (1) It is determined in step S8 that the select lever position is neutral; (2) It is determined in step S9 that the parking brake switch 31 is off and the parking brake 30 is not applied. (3) It is determined in step S10 that the vehicle speed is below the predetermined value SPD1 and the vehicle is in a stopped state; and (4) It is determined that the accelerator pedal 20 is not depressed in step S11. In this case, the check valve 3 is kept energized (step S16). This is because the braking force is still required. However, in step S8, the transmission actuator 13 recognizes the gear position (step S8).
S6) Automatically select lever 17
It can also be determined that is not in neutral.
Further, step S9 is not essential to the present invention. The reason is that the parking brake generates braking force from a completely different system, which eliminates the risk that when the driver pulls the parking brake halfway, the brake pressure already applied will drop due to valve leaks and the braking condition will collapse. Because it's for the sake of it.

Braking force retention mode (1) Mode conditions (1) to (3) are common; (2) It is determined that the accelerator pedal 20 is depressed in step S11; (3) It is determined that the accelerator pedal 20 is already depressed in step S12. Characteristic map of accelerator depression amount and engine speed change rate (negative change rate) determined for each gear (see Figure 4)
is stored in a memory (not shown), an appropriate map is selected according to the gear stage already determined in step S6, and further, in step S13, the braking force is released corresponding to the amount of accelerator depression determined in step S4. Standard engine speed change rate ΔNi
is calculated from the map, the actual rate of change n of the engine speed calculated in step S7 is
It is determined in step S14 that n>ΔNi. If all of the following are satisfied, the braking force is maintained with the check valve 3 energized (step S16). this is,
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.

Braking force release mode (1) It is determined in step S8 that the select lever position is not neutral, (2) It is determined in step S9 that the parking brake switch 31 is on and the parking brake 30 is pulled. (3) It is determined in step S10 that the vehicle speed is equal to or higher than the predetermined value SPDI and the vehicle is not in a stopped state. If either of the following is satisfied, the check valve 3 is deenergized to release the braking force (step S15). This is still
This is because it is determined that the braking force request state has been released.

Braking force release mode Among the conditions (1) to (3) of the holding mode, in step S14 of condition (3), it is determined in step S14 that the actual rate of change n of the engine speed is n≦ΔNi. If the conditions are met, the check valve 3 is deenergized and the braking force is released (step S15). this is,
This is because the increase in the amount of clutch engagement is decreasing and engagement of the clutch is nearing completion, and it is determined that it is desirable to release the braking force in order to start 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 the present invention considers the rate of change in the engine speed in the process of increasing the amount of engagement of the clutch to release 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 have negative rates of change.

〔Effect of the invention〕

As described above, in the braking force retention device for an automatic clutch plate type automatic transmission vehicle of the present invention, the negative change in engine speed in the characteristic map of the accelerator depression amount for each gear and the negative rate of change in engine speed that has already been determined Since the braking force is maintained and released by comparing the negative rate of change in the actual engine speed with the engine speed as a reference, the engine speed is adjusted based on the amount of engagement of the automatic clutch plate in accordance with the actual situation of the vehicle. Changes in the number can be detected and a smooth start can be realized.

[Brief explanation of drawings]

FIG. 1 is a hardware configuration diagram showing one embodiment of the braking force retention device according to the present invention, and FIG. 2 is a hardware configuration diagram showing another application example of the braking force retention device according to the present invention. FIG. 3 is a flowchart mainly for executing the release of braking force among the programs stored in the electronic control device used in the present invention, and FIG. FIG. 3 is a diagram showing a characteristic map of the amount of accelerator depression and the rate of change in engine speed; In the figure, 19 is an engine, 19a is an engine rotation speed sensor, 20a is an accelerator sensor, 12
13 indicates a transmission, 13 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 addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1. Braking force of an automatic transmission vehicle having an engine rotation speed sensor, an accelerator sensor, a gear position sensor, a vehicle speed sensor, and means for controlling an automatic clutch plate based on the output signals of these sensors. In the holding device, the control means increases the clutch engagement amount in accordance with the gear position indicated by the gear position sensor and the depression amount output of the accelerator sensor in a stopped state, and the engine rotational speed is a reference for releasing the braking force. Braking force retention characterized by reading out a negative rate of change of the engine speed and deenergizing the braking electromagnetic check valve when this exceeds the negative rate of change of the actual engine speed obtained from the engine speed sensor. Device. 2. The braking force holding device 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 corresponding to the gear position indicated by the gear position sensor. . 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.