JPS61278454A - Auxiliary device for starting on slope - Google Patents

Abstract

PURPOSE:To effectively prevent reversing or abrupt start on starting, by constituting the device so as to cancel the hydraulic pressure holding caused by the operation of a hydraulic pressure holding valve, when the actual driving torque has reached the target driving torque which is in accordance with vehicle condition on vehicle starting. CONSTITUTION:The device mentioned in the headline has a hydraulic pressure holding valve 5 which is provided in the middle of a brake hydraulic pressure pipe line 4 transferring the hydraulic pressure from master cylinder 2 to wheel cylinder 3 according to the leg power applied to a brake pedal 1, and holds the brake hydraulic pressure when letting the pedal 1 free while parking on a slope. The device also output a cancel signal c for hydraulic pressure holding from a cencel timing control means 8 to a valve actuator 7 which actuates said valve 5 when a signal acknowledging starting state is fed from a sensor 6; said control means 8 is constituted so as to output the cancel signal c when the actual driving torque T from a driving torque sensor 602 has reached the target driving torque T0 obtained from the output of a car condition sensor 601.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a slope start assisting device for a vehicle to facilitate slope start, and particularly to control of release timing of retained hydraulic pressure during slope start.

(Prior art) As a conventional slope start assist device, for example,
The one described in Japanese Patent No.-75182 is known.

This conventional device includes an accelerator switch that detects an accelerator operation for starting the vehicle, a head sensor that detects the inclination of the vehicle in the direction of travel, and an engine rotation speed sensor. On a flat road, the brake lock is released when the accelerator is operated, and when the vehicle head angle exceeds a predetermined value, release of the brake lock is delayed until the engine speed reaches a predetermined value.

(Problem to be Solved by the Invention) However, in such conventional devices, the release timing is controlled by the engine speed regardless of the clutch, so the clutch release state and clutch engagement cannot be controlled. If this is the case in the initial state, the engine speed will increase due to engine speed, etc., and the retained fluid pressure will be released, making it impossible to obtain sufficient starting torque and causing the vehicle to move backwards. In the case where the clutch is fully engaged, there is a problem in that when the engine reaches a predetermined rotational speed at which the retained hydraulic pressure is released, the starting torque becomes too high, resulting in a sudden start.

Furthermore, when the clutch wears out, the clutch engagement position changes, so there is a problem in that the release timing must be corrected in accordance with the change in the engagement position.

(Means for Solving the Problems) The present invention has been made with the aim of solving the above-mentioned problems, focusing on the fact that the driving torque required for starting is not necessarily proportional to the engine speed. In order to achieve this objective, the present invention employs the following solutions.

The solution of the present invention will be explained with reference to the conceptual diagram of the claim shown in FIG. A hydraulic pressure holding valve 5 is provided, which holds the brake fluid pressure even when the brake pedal l is released when stopping on a slope, and releases the brake fluid pressure when starting on a slope, and a signal indicating a predetermined starting state is sent from an input sensor 6. In the slope start assisting device, the slope start assist device includes a release timing control means 8 which outputs a release signal (C) to the valve actuator 7 to release the retained fluid pressure when the input sensor 6 is input to the release timing control means 8. A vehicle condition sensor 601 that detects the state, and a drive torque sensor 6 that detects the drive torque from the engine via the clutch.
02, and the release timing control means 8 outputs a release signal (C) when the actual drive torque T detected by the drive torque sensor 602 reaches the target drive torque TO corresponding to the vehicle state at the time of starting.

(Function) Therefore, in the hill start assisting device of the present invention, as described above, by using a means for releasing the hydraulic pressure retention when the actual drive torque reaches the target drive torque depending on the vehicle condition at the time of start, The holding fluid pressure is released when the driving torque required for starting is reached, and smooth starting on a slope can be ensured without backing up or suddenly starting the vehicle.

(Example) Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

In describing this embodiment, we will focus on the hill start assist device (first embodiment) used for vehicles whose vehicle weight changes significantly due to loading of luggage, and the hill start assist device (second embodiment) used for vehicles such as passenger cars. Take example).

First, the configuration of the first embodiment will be explained.

As shown in FIG. 2, the hill start assist device A of the first embodiment includes a brake pedal 10, a booster 11, a tandem master cylinder 12. Primary side brake hydraulic piping system 13
, secondary brake hydraulic piping system 14, front wheel cylinder 15.16. Rear wheel cylinder 1
7,18. It is equipped with a hydraulic pressure holding valve 19, an input sensor 20, and a control unit 21, and each configuration will be described in detail below.

The brake pedal 10 is connected to a valve operating rod of a booster 11.

The booth 711 is a booster that increases the brake pedal force applied to the brake pedal 10 by using engine negative pressure, etc. The brake pedal force increased by the booster 11 is applied to the primary piston of the tandem master cylinder 12 and applied to a secondary piston (not shown).

The tandem master cylinder 12 converts the brake pedal force from the booster 11 into brake fluid pressure, and the tandem master cylinder 12 is formed with two independent fluid pressure generating chambers corresponding to a primary piston and a secondary piston. ing.

The primary brake hydraulic piping system 13 transfers the brake hydraulic pressure from the primary hydraulic port 22 of the tandem master cylinder 12 to the front wheel cylinders 15, 16.
This is the piping system that supplies the

The secondary brake hydraulic piping system 14 is a piping system that supplies the brake hydraulic pressure from the secondary hydraulic port 23 of the tandem master cylinder 12 to the rear wheel cylinders 17 and 18. A hydraulic pressure holding valve 19 is provided.

The secondary brake hydraulic piping system 14 includes a master cylinder brake pipe 141 and a wheel cylinder brake pipe 142.

The front wheel cylinders 15, 16 and the rear wheel cylinders 17, 18 operate brake devices such as drum brakes or disc brakes, and the braking force is proportional to the magnitude of brake fluid pressure.

The hydraulic pressure holding valve 19 is provided in the middle of the secondary brake hydraulic piping system 22, and maintains the current brake hydraulic pressure even when the brake pedal 10 is released when stopping on a slope, and maintains the brake hydraulic pressure when starting on a slope. As shown in FIG.
Input port 25, output port 26, plunger chamber 27,
It includes a pole chamber 28, a pole valve 29, a valve seat 30, a plunger 31, a plunger spring 32, and a solenoid (valve actuator) 33.

This hydraulic pressure holding valve 19 consists of a pole valve 29 and a valve seat 3.
0 constitutes a valve, and plunger spring 3
In the valve open state where the pole valve 29 is prevented from seating on the valve seat 30 by the biasing force of
-> Pole chamber 28 -> Output boat 26 and is directly supplied to the wheel cylinders 17, 18.

Note that for the solenoid 33, the control unit 2
When the energization signal (i) is output from 1, the plunger 31
moves downward in the drawing against the plunger spring 32, and the pawl valve 29 is seated on the valve seat 30 to be in the valve closed state, and the master cylinder hydraulic pressure Pm when the valve is closed is
It is held by the wheel cylinder side brake pipe 142 and the rear wheel cylinder 17,18.

The input sensor 20 is provided to obtain input signals for hydraulic pressure holding timing control for holding the brake hydraulic pressure and release timing control for releasing the brake hydraulic pressure holding. 201, clutch sensor 202, shift position sensor 203, vehicle weight sensor 2
04, vehicle weight sensor 205, engine torque sensor 206
It is equipped with

Vehicle speed sensor 201 is a sensor that detects vehicle speed and outputs a vehicle speed signal (V).

The clutch sensor 202 is a sensor that detects whether the clutch is in an engaged state or an open state and outputs a clutch signal (k).

The shift position sensor 203 is a sensor that detects the shift position of the transmission and outputs a shift position signal (p).

The vehicle weight sensor 204 is a sensor that detects the inclination of the vehicle and outputs a vehicle weight signal (θ) according to the inclination.

The vehicle weight sensor 205 detects the vehicle weight and outputs a vehicle weight signal (m
), such as a stroke sensor that detects the distance between the sprung mass and the unsprung mass.

The engine torque sensor 20B is a sensor that detects the crankshaft torque of the engine and outputs a drive torque signal (1).

In addition, in the first embodiment, as a vehicle state sensor at the time of one start,
A vehicle weight sensor 204 and a vehicle weight sensor 205 are used.

The control unit 21 outputs an energization signal (i) to the solenoid 33 when a signal indicating a predetermined slope stop state is input from the input sensor 20, and also outputs a signal from the input sensor 20 indicating a predetermined starting state. is input, the control means outputs a deenergization signal (n) to the solenoid 33, and as shown in FIG.
, ROM (read, only, memory) 213, CPU
(Central, Processing 2 Units)) 214. An on-vehicle microcomputer equipped with a clock circuit 215 and a control signal generation circuit 216 is used.

The A-D conversion circuit 211 is a circuit that converts an analog input signal from the input sensor 20 into a digital signal that can be processed by the CPU 214.

RAM212 is a memory that can be written and read.
Until the input signal is processed by the CPU 214,
Write temporarily, or temporarily write necessary information during arithmetic processing.

The ROM 213 is a read-only memory, and the CPU 21
The information necessary for the arithmetic processing in step 4 is stored in advance in the form of tables and arithmetic expressions.

Note that, as shown in FIG. 4, the ROM 213 stores in advance the relationship between the vehicle weight angle θ and the target engine torque To in the form of a table.

The CPU 214 is called a central processing unit.
This circuit reads information from the RAM 212 or ROM 213 as necessary, processes the information according to a predetermined arithmetic processing procedure, and outputs the result signal to the control signal generation circuit 216.

The clock circuit 215 is a circuit that sets the calculation processing time in the CPU 214.

The control signal generation circuit 216 is a circuit that outputs an energization signal (i) and a energization release signal (n) as control signals based on a result signal from the CPU 214.

Next, the operation of the first embodiment will be explained.

(a) Hydraulic pressure holding timing control control unit 21 controls the hydraulic pressure holding timing of the brake hydraulic pressure according to the flow of control operations shown in the flowchart of FIG.

In step 100, the vehicle speed signal (V) from the vehicle speed sensor 201, the clutch signal (k) from the clutch sensor 202,
), the shift position signal from the shift position sensor 203 (p
) and the vehicle weight signal (θ) from the vehicle weight sensor 204 are read.

In step 101, it is determined whether the vehicle speed signal (V) read in step 100 is a signal indicating that the vehicle speed is zero, and if it is determined that the vehicle speed is zero (stopped state), the process proceeds to the next step 102, If it is determined that the vehicle speed is not zero (running state), the process returns to step 100.

In step 102, it is determined whether the clutch signal (k) read in step 100 is a signal indicating clutch disengagement or clutch engagement. If it is determined that the clutch is in the disengaged state, the process proceeds to step 103. If it is determined that the clutch is engaged, the process returns to step 100.

In step 103, based on the shift position signal (p) read in step 100, it is determined whether the shift position is a signal indicating the first gear position or reverse position, or a signal indicating another shift position, and If it is determined that the vehicle is in the reverse position, proceed to the next step 103, and if it is determined that the vehicle is in any other forward position, step 100
Return to

In step 104, it is determined whether the actual vehicle weight angle θ is a signal indicating that the set vehicle inclination angle is 00 or more, based on the vehicle weight signal (θ) read in step 100, and when θ≧00, Proceed to the next step 104, and
If so, the process returns to step 100.

In step 105, the condition that the vehicle is stopped on a slope and the brake fluid pressure must be maintained is set in step 101.10.
2, 103, and 104, it is determined that the condition is satisfied, and the control unit 21 outputs an energization signal (i) to the solenoid 33 of the hydraulic pressure holding valve 19.

Due to this flow of operation, when the energization signal (i) is output to the solenoid, the plunger 31 of the hydraulic pressure holding valve 19 is forcibly moved downward in the drawing by electromagnetic force against the plunger spring 32. At the same time,
By seating the ball valve 29 on the one-valve seat 30, the master cylinder hydraulic pressure Pm from the tandem master cylinder 12 is maintained when the ball valve 29 is seated, and thereafter the brake pedal lO
The hydraulic pressure is maintained even if you take your foot off.

Note that the energization signal (i) to the solenoid 33 remains output unless a predetermined release condition is satisfied in the release timing control described below.

In addition, when trying to increase the retained fluid pressure, by depressing the brake pedal lO again and sending the master cylinder hydraulic pressure Pm higher than the retained fluid pressure, the ball valve 29 is temporarily separated from the valve seat 30, and the retained fluid pressure can be increased.

(b) Release Timing Control The release timing control for releasing the brake fluid pressure from being held in the control unit 21 is performed according to the flow of control operations as shown in the flowchart of FIG.

In step 106, the vehicle weight signal (θ) from the vehicle weight sensor 204 and the vehicle weight signal (m) from the vehicle weight sensor 205 are read.

In step 107, the target engine torque TO for the vehicle weight angle θ is looked up in a table based on the vehicle weight signal (θ) read in step 106.

For example, as shown in FIG. 4, when the vehicle weight angle θ is 01, the target engine torque TO becomes Tol.

In step 108, based on the vehicle weight signal (m) read in step 106, a table look-up torque TO is corrected in step 107, and the final target engine torque To' is set by the correction.

For example, as shown in FIG. 4, when the vehicle weight signal (m) indicates that the vehicle weight is large, the target engine torque T01 is
1'.

In step 109, the engine torque signal (1) from the engine torque sensor 206 is read.

In step 110, the target engine torque To' calculated in step 108 and the engine torque signal (
1) is compared with the actual engine torque T, and if the actual engine torque T is less than or equal to the target engine torque To'(T<To'), steps 109→110 are repeated, and the actual engine torque The point in time when T becomes greater than or equal to the target engine torque To'(T≧TO')
Then, the process advances to the next step 111.

In step 111, the control unit 21 outputs the de-energization signal (n) to the solenoid 33 of the hydraulic pressure holding valve 19. Due to this flow of operation,
When the de-energization signal (n) is output to the solenoid 33, the plunger 31 of the hydraulic pressure holding valve 19 moves upward in the drawing by the biasing force of the plunger spring 32, pushes up the ball valve 29, and closes the ball valve 29. It is pulled away from the seat 30 and the retained hydraulic pressure is released to the tandem master cylinder 12, and the hydraulic pressure maintained state is released.

As described above, in the first embodiment, the actual engine torque T is equal to the target engine torque To depending on the vehicle state at the time of starting.
Since the hydraulic pressure retention is released when it reaches ', the release timing is done when the engine torque necessary for starting is reached, so the vehicle does not back up due to insufficient torque or suddenly start due to excessive torque when starting. Smooth hill start is possible.

Further, in the first embodiment, when setting the target engine torque TO, the target engine torque TO is set in stepless proportion to the vehicle weight angle θ.

It is possible to ensure smoother starting running when starting on a slope.

Furthermore, in the first embodiment, by maintaining and releasing the hydraulic pressure even when reversing, it is possible to cope with starting in reverse from a slope.

Furthermore, in the first embodiment, when setting the final target engine torque To', the vehicle weight is taken into consideration, making it suitable for application to vehicles such as trucks that have large changes in vehicle weight. It is.

Next, a second embodiment shown in FIG. 7 will be described.

In this embodiment, a hydraulic pressure holding valve 19' corresponding to two systems of brake hydraulic piping is used, and a vehicle speed sensor 201, a reverse switch 207, a vehicle weight sensor 204, and a drive wheel torque sensor 208 are used as input sensors 20. This is an example.

The hydraulic pressure holding valve 19' of the second embodiment has a valve body 5
0, first hydraulic injection cover 51. First input chamber 52, first piston 53, piston spring 54, first valve 55
, first valve spring 56, first valve seat 57,
First valve chamber 58, first hydraulic output port 591, stepped piston 60, piston spring 61, second hydraulic pressure input capo
The valve 2 includes a second valve 2, a second piston 63, a second valve 64, a second valve spring 65, a second valve seat 66, a second valve chamber 67, a second hydraulic pressure outlet 8, and a solenoid 69.

The first hydraulic injection capo 51 is connected by a pipe to the primary side hydraulic boat of a tandem master cylinder (not shown), and the second hydraulic injection capotro 2 is connected by a pipe to the secondary hydraulic boat. be done.

Further, the first hydraulic pressure output boat 59 is pipe-connected to the left front wheel cylinder and the right rear wheel cylinder, and the second hydraulic pressure output boat 8 is connected to the right front wheel cylinder and the left rear wheel cylinder. The pipe is connected to the pipe, making it what is called x piping.

Next, the operation of the second embodiment will be described.

The hydraulic pressure holding timing control is performed when the vehicle speed signal (V) from the vehicle speed sensor 201 is a signal indicating zero vehicle speed, and the switch signal (V) from the reverse switch 207 is a signal indicating a forward gear other than reverse. The control unit 21' outputs an energization signal (i) to the solenoid 69 to maintain the hydraulic pressure.

In the release timing control, a target driving wheel torque To which is proportional to the vehicle weight angle θ is determined by table lookup or calculation based on the vehicle weight signal (θ) from the vehicle weight sensor 204, and the driving wheel torque To is calculated based on the target driving wheel torque To. When the actual driving wheel torque T based on the driving wheel torque signal (W) from the torque sensor 208 is reached, a de-energization signal (n) is output from the control unit 21' to the solenoid 69 to release the brake fluid pressure. will be done.

The hydraulic pressure holding valve 19' operates by opening and closing the two valves in the same manner as in the first embodiment.

Although the embodiments of the present invention have been described above in detail with reference to the drawings, the specific configuration is not limited to these embodiments, and the present invention may be modified without departing from the gist of the present invention. included.

For example, in the embodiment, an example was shown in which a vehicle weight sensor or a vehicle weight sensor was used as the vehicle condition sensor, but any sensor that detects the vehicle condition at the time of starting may be used.
For example, a road surface friction coefficient sensor or the like may be added.

Further, in the embodiment, an engine torque sensor and a drive wheel torque sensor are shown as the drive torque sensor, but the sensor is not limited to the embodiment as long as it detects the torque of the power train system from the engine to the drive wheels. The driving torque may be indirectly detected by detecting both the engine rotation speed and clutch engagement.

(Effects of the Invention) As explained above, the hill start assist device of the present invention has a configuration in which hydraulic pressure retention is released when the actual drive torque reaches the target drive torque depending on the vehicle condition at the time of start. Therefore, the holding fluid pressure is released when the driving torque required for starting is reached, and the effect is that smooth starting on a slope can be ensured without the need for the vehicle to back up or start suddenly at the time of starting.

[Brief explanation of drawings]

Fig. 1 is a conceptual diagram of claims showing the hill/road starting assist device of the present invention, Fig. 2 is an overall view showing the hill starting assist device of the first embodiment of the present invention, and Fig. 3 is a main part of the device of the first embodiment. A diagram showing the parts;
Fig. 4 is a graph showing the relationship between the vehicle weight angle and target engine torque stored in advance in the control unit of the device of the first embodiment, and Fig. 5 is the hydraulic pressure holding timing in the control unit of the device of the first embodiment. FIG. 6 is a flowchart showing the flow of control operations, and FIG. 6 is a flowchart showing the flow of release timing control in the control unit of the device of the first embodiment. FIG. 7 is a main part of the device of the second embodiment. It is a diagram. 1... Brake pedal 2... Master cylinder 3... Wheel cylinder 4... Brake hydraulic piping system 5... Fluid pressure holding valve 6... Input sensor soi... Vehicle condition sensor 602. ... Drive torque sensor 7 ... Valve actuator 8 ... Release timing control means (C) ... Release signal output t4 & - (e) Fig. 5

Claims (1)

[Claims] 1) A brake fluid pressure piping system that supplies fluid pressure from the master cylinder to the wheel cylinders in accordance with the force applied to the brake pedal, so that when stopping on a slope, the brake fluid pressure is maintained even when the brake pedal is released. A hydraulic pressure holding valve that holds the brake fluid pressure and releases the brake fluid pressure when starting on a slope, and outputs a release signal that causes the valve actuator to release the held hydraulic pressure when a signal indicating a predetermined starting condition is input from the input sensor. In the hill start assisting device, the input sensor includes a vehicle condition sensor that detects the vehicle condition at the time of starting, and a drive torque sensor that detects the drive torque from the engine via the clutch. 1. A hill start assisting device comprising: release timing control means for outputting a release signal when the actual drive torque measured by the drive torque sensor reaches a target drive torque depending on the vehicle state at the time of start.