JPS62292541A - Brake force holding controller - Google Patents

Abstract

PURPOSE:To achieve a smooth starting by providing means for detecting the brake force and determining a time interval from the start of clutching operation to the hold release operation according to the brake force at the start of holding operation. CONSTITUTION:When a braking solenoid check valve 3 is not functioning, the pressure level detected by means of a control pressure sensor 2a is stored by means of a controller 6. Then a current level read out through the sensor 2a is compared with a previously stored pressure level, and if the pressure level at current time point is higher, the current read-out level is stored again so as to store the maximum level at all times. A time interval from the start of clutching operation to the hold releasing operation, i.e. the time interval until the solenoid check valve 3 is opened, is determined according to the stored pressure level. Consequently, the brake force can be released with a proper timing corresponding to the traveling condition of vehicle thus achieving a smooth hill start easily.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a braking force retention control device for a vehicle equipped with an automatic transmission controlled by an electronic control device.

(Prior art) When starting a vehicle stopped on a road, in conventional vehicles, the driver's operations are to use the handbrake with one hand to apply braking force to the vehicle to maintain the stopped F state, and then apply the clutch. However, since the brake and accelerator must be coordinated in a complex manner, it takes skill to start the car smoothly, and this can lead to what is called an engine stall. Or! ■(There was a problem that caused both sides to retreat.

(Problems to be Solved by the Invention) In order to solve these problems, the applicant has proposed a braking force holding device as disclosed in, for example, Japanese Patent Application Laid-open No. 11719/1983.

This is a vehicle equipped with a synchronous gear automatic transmission with a friction clutch that is controlled by an electronic control device, and uses a clutch fluid pressure actuator to control the signals from various detection devices in the vehicle. The braking force is maintained until the brake is engaged, and by controlling the braking force retention, it is possible to restart the vehicle smoothly on an uphill slope without requiring any skill.

However, since the braking force holding device always releases the braking check valve at a constant clutch engagement position, depending on the slope of the road surface, the braking may be released too quickly, causing the vehicle to move backwards, or Inconveniences such as the brake being released and the vehicle jumping out may occur.

The present invention has been made in view of the above points, and provides braking force retention control that facilitates smooth starting by releasing the braking force at an appropriate timing according to the driving situation of the vehicle. The purpose is to provide equipment.

(Means for solving the problem) In order to achieve the above-mentioned object, according to the present invention, braking force is maintained and controlled in synchronization with the engagement state of the clutch controlled by a signal from an electronic control device. The braking force retention control device includes a sensor means for detecting the braking force, and a determining means for determining the time from the start of the engagement operation of the clutch to the release of the holding operation according to the braking force at the start of the holding operation. A braking force retention control device is provided.

(Function) In the present invention, even if the vehicle stops once on a slope of any slope, the optimum release timing can be determined according to the braking force at the time of stopping, and the time taken into account the gear for restarting. Can be configured.

(Example) Hereinafter, an example of a braking force retention control device for a vehicle to which the device of the present invention is applied will be described in detail with reference to the drawings.

1 and 2 are block diagrams showing two systems of the vehicle, and FIG. 3 is a flowchart explaining the operation of the device of the present invention.

In FIG. 1, 1 is a brake pedal, la is a brake pedal switch, 2 is a mask cylinder, 2a is a braking pressure sensor, 3 is a braking electromagnetic check valve, 4 is a wheel cylinder, and 5 is an electromagnetic coil.

These constitute a braking device A. The braking electromagnetic check valve 3 is connected from the master cylinder 2 to the wheel cylinder 4.
A check valve 3a configured to allow the flow of braking fluid in the direction toward, but prevent flow in the opposite direction.
and an electromagnetic switching valve 3b arranged in parallel to the check valve 3a, and the electromagnetic switching valve 3b is switched by an electromagnetic coil 5 to control the flow of braking fluid.

Therefore, while the 'rrL magnetic coil 5 is energized, the brake holding mechanism 1 is maintained by the braking electromagnetic check valve 3 regardless of the brake pedal l, and when it is deenergized, the brake is held. The operation is canceled.

The braking pressure sensor 2a is installed in a braking piping system that connects the mask cylinder 2, which is a braking pressure source, and the wheel cylinder 4, which applies braking force to the vehicle. The magnitude of the braking force acting on the cylinder 4 is detected as a braking pressure signal.

6 is an electronic control device consisting of a microcomputer, which includes the brake pedal sensor 1a and the braking pressure sensor 2a.
It also controls signals from various detection devices of the vehicle, which will be described later, to energize or de-energize the electromagnetic coil 5 to maintain braking force in synchronization with the engaged state of the clutch. ing. Further, 7 is a fluid pressure source, 8 is a tank, 9 is a solenoid valve for a clutch actuator, 10 is a clutch actuator, lOa is a clutch stroke sensor, 11
is a friction clutch, and these are clutch devices 2! It constitutes the IB.

12 is a transmission; 13 is an actuator for the transmission; the output shaft 12a of the transmission a12 is connected to the 1 operation gear 14, and transmits its output to the wheels 15; Above transmission 1
A vehicle speed sensor 16 is provided on the output shaft 12a side of the vehicle 2, and its output signal is supplied to the electronic control device 6. A select lever 17 is connected to the electronic control device 6 via a select position switch 18, whereby a predetermined gear of the transmission 12 can be set.

19 is an engine connected to the clutch 11,
The rotation speed of the engine 19 is controlled by opening and closing the throttle valve 19b by pressing the accelerator pedal 20. This engine 19 has an engine rotation sensor 19a.
is provided, and its output signal is supplied to the electronic control unit 6 together with the output signal of an accelerator pedal sensor 20a provided on the accelerator pedal 20. The signal from the accelerator pedal sensor 20a causes the accelerator pedal 2 to
0 is detected and processed in the electronic control unit 6 as the starting point of the clutch engagement operation.

The system shown in FIG. 2 brakes a vehicle using air pressure, and is used as a braking force holding device, especially for large vehicles, and is different from the system shown in FIG. 1 in the brake system NA.

That is, an air master 41 is provided in place of the mask cylinder 2, and an air tank 40 is provided as a braking pressure supply source, and when the brake pedal 1 is depressed, the brake valve lb is opened and the wheel cylinder 4 is operated. The apparatus is constructed in the same manner as that shown in FIG. 1 except for the following structure.Next, the operation of the apparatus of the present invention will be explained based on the flowchart shown in FIG.

In the figure, steps a to g are steps for determining various conditions for energizing the coil 5 to bring the braking device A into a braking force holding state (step j), in which the select lever 17 is in the neutral position ( = O) (step a), the vehicle speed is O (step b), the engine speed is equal to or higher than the set rotation speed (=NO) (step C), and the accelerator pedal 20 is not depressed. thing(
Step d), the pressure value detected by the braking pressure sensor 2a is equal to or higher than the set pressure ("po") (step e), and the clutch stroke detected by the clutch stroke sensor 10a is lower than the set position (=CG). (step f), and since there is a possibility that a wheel lock has occurred immediately after a sudden stop, step h is provided on the condition that the wheel is not immediately after a sudden stop (step g).
In step h, it is determined whether or not the braking electromagnetic check valve 3 is in operation, and when it is determined that it is not in operation, the pressure value detected by the brake pressure sensor 2a is controlled by electronic control. stored in device 6 (step i).

In this way, the electronic control device 6 always includes the braking electromagnetic check valve 3.
The maximum value immediately before the operation, that is, the magnitude of the braking force at the start of the holding operation is stored.

When it is determined that the select lever 17 is in the neutral position in step a, or when it is determined that the stopping process is a sudden stop in step g, the braking electromagnetic check valve 3 is opened and the holding operation is performed. is immediately released (step 0). Furthermore, if the conditions for bringing the braking device A into a braking force holding state are not met in steps b to f of E, the process moves to step k. In this step, the reading value of the brake pressure sensor 2a is compared with the pressure value stored in the previous step i, and if the current pressure value is larger, this reading value is stored again. I have to.

Depending on the pressure value stored in this way, the clutch can be changed from the start of the clutch engagement operation to the release of the holding operation, that is, the braking electric positive reversing valve 3
Determine the time Ti until it is released (step m).

That is, this time Ti is.

It is experimentally determined by the magnitude of the braking force applied to the wheel cylinder 4 by depressing the brake pedal 1, and is stored in advance as a map in the electronic control unit 6. By referring to such a map, the time [I T i is found. Further, in setting the above map, it is preferable that a different map is prepared depending on the gear stage selected when the clutch 11 is engaged. If it is possible to determine the starting stage at which to release the hold and restart the vehicle, smooth braking force hold control can be used even when starting outside of the single chain, such as when restarting on a gentle slope. be.

1; After determining the time Ti until the holding of the braking force is released in step m, the electronic control device 6 uses the depression signal for restarting the vehicle as a signal to start the engagement operation of the clutch 11, and starts a timing operation; The count value t is compared with the above time Ti (step n), and when Ti=t,
The excitation current from the electronic control device 6 to the electromagnetic coil 5 is turned off, the electromagnetic switching valve 3b is opened, the braking force holding operation is released, and the stored pressure value is cleared (step O). By continuing to press the accelerator pedal 20, a hill start can be performed. Further, while Ti>t, the cycle of steps a to n described above is repeated at the set time period without releasing the holding operation. At this time, the select lever 17 is selected to the start gear. The engagement operation of the friction clutch 11 is automatically performed in response to a predetermined signal from the electronic control device 6. Since this point is not directly related to the present invention, further explanation will be omitted.

In the description of the above embodiment, the braking force retention control of a vehicle equipped with a synchronous toothing automatic transmission with a friction clutch controlled by an electronic control device was described; however, the present invention is not limited to this. For example, since the braking force retention time is determined based on the start point of the clutch engagement operation, the clutch stroke cannot be detected, especially in automatic transmissions that use a torque converter. It goes without saying that the holding control can be effectively applied to vehicles, and can be modified in various ways within the scope of the present invention depending on the characteristics of the vehicle and its electronically controlled bag.

(Effects of the Invention) As described above, according to the present invention, it is possible to reliably prevent the conventional phenomena such as when the brake is released too early and the vehicle moves backwards when starting on a slope, or when the brake is released too late and the vehicle jumps out. It is possible to provide a braking force retention control bag that prevents the vehicle from moving and releases the braking force at an appropriate timing according to the driving situation of the vehicle, thereby making it easy to start smoothly.

[Brief explanation of the drawing]

FIGS. 1 and 2 are block diagrams showing an embodiment in which the device of the present invention is applied to two systems of a vehicle, and FIG. 3 is a flowchart illustrating the operation of the device of the present invention. l... Brake pedal, 2... Mask cylinder, 2
a... Braking pressure sensor, 3... Braking type Fi1 check valve, 4... Wheel cylinder, 6... Electronic control device, 11... Friction clutch.

Claims (2)

[Claims] (1) A braking force holding control device that holds and controls braking force in synchronization with the engagement state of a clutch controlled by a signal from an electronic control device, which includes a sensor means for detecting the braking force, and a sensor means for detecting the braking force, and A braking force retention control device comprising: determining means for determining the time from the start of the engagement operation of the clutch to the release of the holding operation according to the braking force. (2) The braking force retention control device according to claim (1), wherein the determining means is selected in accordance with the gear stage selected when the clutch is engaged. .