JPH0769102A - Stopper on slope - Google Patents

Abstract

PURPOSE:To provide a stopper on slope which is constituted to prevent a vehicle from retreating by adding a control force to the wheels according to the inclined angle of a slope, when the vehicle stops on any slope. CONSTITUTION:A stopper on slope comprises an inclination angle detection means A1 for detecting an inclination angle of a slope, a retreat force estimation means A2 for estimating retreat force acting on a vehicle based on the detected angle by the inclination angle detection means A1, a drive force estimation means A3 for estimating drive force transmitted from an engine to the drive wheels of the vehicle, and a braking force adding means A4 for adding braking force balancing with the above retreat force based on deviation between the retreat force estimated by the retreat force estimation means A2 and the drive force estimated by the drive force estimation means A3, when the vehicle stops on the slope.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a slope stopping device, and more particularly to a slope stopping device configured to prevent a vehicle from moving backward when the vehicle is stopped on a slope.

[0002]

2. Description of the Related Art For example, when a vehicle such as an automobile goes up a slope, the vehicle may be stopped in the middle of the slope due to a signal or a temporary lane. In such a case, the driver continuously depresses the brake pedal to secure the braking force, or temporarily operates the parking brake and then starts the slope.

At this time, if the driving force transmitted to the driving wheels of the vehicle is small with respect to the slope (inclination angle) of the slope, the vehicle retreats when the depression force of the brake pedal is loosened or the parking brake is loosened. Will be done. A hill road stop device has been developed to prevent the vehicle from moving backward when the hill road is stopped or when the hill starts.

As an example of this kind of slope stop device, as shown in, for example, Japanese Utility Model Laid-Open No. 62-79661, a vehicle is based on a signal from a speed sensor, an inclination sensor, an accelerator switch, etc. and an engine speed. There is a device configured to shut off a brake hydraulic circuit by closing a solenoid valve provided in the middle of a pipe connecting a master cylinder and a brake device when it is determined to move backward.

[0005]

However, in the above slope road stop device, the inclination sensor detects a stop on an uphill road to hold the braking force of the brake device, and the accelerator is operated to keep the engine speed at a predetermined speed. When the (inflection point) is reached, the braking holding of the brake device is released. However, even if the engine speed reaches a predetermined speed, for example, depending on the slope of the slope, the Since the driving force may be less than the reverse force acting on the vehicle,
If the brake holding of the brake device is released when the vehicle is started, the vehicle moves backward.

That is, in the above-mentioned slope stop device, the fluctuation of the retreating force according to the magnitude of the slope of the slope is not considered, and the holding of the braking force by the brake device can be finely adjusted according to the slope of the slope. could not.

Therefore, in view of the above problems, it is an object of the present invention to provide a slope stop device configured to prevent a vehicle stopped on an uphill from moving backward regardless of the slope of the slope.

[0008]

FIG. 1 shows the principle of the present invention. As shown in the figure, the present invention relates to an inclination angle detecting means A1 for detecting an inclination angle of a slope, and a backward force estimating means for estimating a backward force acting on a vehicle based on the angle detected by the inclination angle detecting means A1. A2, a driving force estimating means A3 for estimating the driving force from the engine transmitted to the driving wheels of the vehicle, and the reverse force estimated by the reverse force estimating means A2 when the vehicle is stopped on a slope and the backward force. A braking force adding means A4 for adding a braking force that balances the retreating force based on the deviation from the driving force estimated by the driving force estimating means A3.
And is made up of.

[0009]

According to the present invention, when the vehicle stops on a slope, a stopping force that balances with the reverse force is added based on the deviation between the reverse force estimated by the reverse force estimating means and the drive force estimated by the drive force estimating means. By doing so, the vehicle can be stopped on a slope, and the braking force can be released and the vehicle can be started at the time when it is estimated that the driving force balanced with the backward force corresponding to the inclination angle of the slope is transmitted to the drive wheels. , It is possible to prevent the vehicle from moving backward when starting.

[0010]

FIG. 2 and FIG. 3 show an embodiment of a slope stop apparatus according to the present invention.

In both figures, a vehicle having an acceleration slip control device 1 includes a brake master cylinder 2, wheel cylinders 5 and 6 of left and right front wheels 3 and 4 which are idle wheels, and left and right rear wheels 7 and 8 which are drive wheels. An oil pressure source 11, an anti-skid control hydraulic circuit 12, and an acceleration slip control hydraulic circuit 13 are provided between the wheel cylinders 9 and 10. The vehicle of this embodiment is an automobile equipped with an automatic transmission.

In the brake hydraulic circuit from the first hydraulic chamber 2a of the brake master cylinder 2 to the wheel cylinders 5, 6 of the left and right front wheels 3, 4, left and right front wheel anti-skid control displacement control valves 14, 15 are arranged. It is set up. Further, in the brake hydraulic circuit from the second hydraulic chamber 2b of the brake master cylinder 2 to the wheel cylinders 9 and 10 of the left and right rear wheels 7 and 8, a proportioning valve 16, a rear wheel anti-skid control capacity control valve 17, A first solenoid valve 18, a check valve 19 and a displacement control valve 20 for acceleration slip control, which are arranged in parallel, are provided.

At the time of anti-skid control, the first solenoid valve 18 is not excited and is in the position shown in the figure.
The rear wheel anti-skid control capacity control valve 17 and the acceleration slip control capacity control valve 20 are kept in communication with each other. or,
Control input port 2 of the displacement control valve 20 for acceleration slip control
0a, the second solenoid valve 21 and the third solenoid valve 22 which are arranged in series are not excited and both are in the positions shown in the figure.
Are kept in communication with the reservoir 23 of the hydraulic power source 11.

Therefore, the acceleration slip control displacement control valve 2
The zero pickup 20c is held at the position shown by the bias of the spring 20d. At this time, the rear wheel anti-skid control displacement control valve 17 is not excited / de-energized with the rear wheel second switching valve 25 connected in series with the rear wheel first switching valve 24 communicating with the first control input port 17a. It changes into the following three states depending on the combination of excitation.

(1) Pump drive motor 26 of hydraulic source 11
Output port 29a of the regulator 29 that converts the hydraulic pressure from the pump 27 driven by the pump and the accumulator 28 that accumulates the hydraulic pressure into the hydraulic pressure according to the brake operation amount.
And a communication state with the first control input port 17a, (2) first control input port 17a, regulator 29,
Shutdown state with each of the reservoirs 23, (3) Communication state between the first control input port 17a and the reservoir 23.

The second control input port 17a is in constant communication with the output port 29a of the regulator 29. Therefore, the rear wheel anti-skid control displacement control valve 17 operates in the following manner in correspondence with the above three states.

That is, the pressure in the first hydraulic chamber 17c having the first control input port 17a is increased (1), maintained (2) or reduced (3) to the pressure in the first hydraulic chamber 17c. Accordingly, the volume of the brake hydraulic chamber 17d changes.
As a result, the rear wheel anti-skid control displacement control valve 17
Increases (1), maintains pressure (2) or reduces (3) the pressure in the left and right rear wheel cylinders 9 and 10 via the first solenoid valve 18 or the check valve 19.

The left front wheel first and second switching valves 30, 31,
By the excitation and de-excitation of the right front wheel first and second switching valves 32 and 33, the left and right front wheel anti-skid control displacement control valves 14,
15 also acts similarly on the left and right front wheel cylinders 5, 6. Each switching valve 24, 25, 30, 3 as described above
Excitation / de-excitation of 1, 32 and 33 is performed by an anti-skid control device (not shown).

During the acceleration slip control, the first solenoid valve 18 is excited to switch to the cutoff state. Therefore, the first solenoid valve 18 and the check valve 19
As a result, the communication between the rear wheel anti-skid control capacity control valve 17 and the acceleration slip control capacity control valve 20 is cut off. At this time, the acceleration slip control displacement control valve 20
Changes to the following four states depending on the combination of excitation and non-excitation of the second and third solenoid valves 21 and 22 communicating with the control input port 20a.

(11) Communication between the accumulator 28 and the control input port 20a, (12) Communication between the accumulator 28 and the control input port 20a via a throttle valve, (13) Connection between the reservoir 23 and the control input port 20a. The communication state via the throttle valve, (14) The communication state between the reservoir 23 and the control input port 20a, therefore, the acceleration slip control capacity control valve 20 operates as follows corresponding to the above four states.

That is, the pressure in the control hydraulic chamber 20b having the control input port 20a is increased (11) and gradually increased (1
2), the volume in the control hydraulic chamber 20b is changed by gradually reducing (13) or gradually reducing (14), and the piston 20c resists the biasing force of the spring 20d.
Move to the center left and right.

As a result, hydraulic pressure is supplied from the output port 20f of the brake hydraulic chamber 20e to the left and right rear wheel wheel cylinders 9 and 10. Therefore, the pressure in the left and right rear wheel cylinders 9, 10 is increased (11), gradually increased (12), gradually reduced (13), or gradually reduced (1
4) Do.

The acceleration slip control device 1 includes a pedal switch 34 that outputs an ON / OFF signal in response to an operation of the brake pedal 34a, a left front wheel rotation speed sensor 35 that detects the rotation speed of the left front wheel 3, and a rotation of the right front wheel 4. A front right wheel rotation speed sensor 36 for detecting speed, a rear wheel rotation speed sensor 37 for detecting left and right rear wheel rotation speeds, an engine rotation speed sensor 38 for detecting engine rotation speed, and an acceleration sensor for detecting vehicle acceleration. It is equipped with 39. The detection signal output from the acceleration sensor 39 is used, for example, to correct the estimated vehicle speed during deceleration when performing acceleration slip control, and also obtains the vehicle inclination angle in the front-rear direction as described later. Used to.

The detection signals output from the sensors 35 to 39 are input to the acceleration slip control circuit 40. or,
The acceleration slip control circuit 40 includes the first to third solenoid valves 18, 21, 22 and the pump drive motor 26.
Drive control.

Further, the acceleration slip control device 1 detects the occurrence of slip based on the difference between the vehicle speed and the wheel rotation speed based on the detection signals output from the sensors 35 to 39, and the engine prior to the acceleration slip control by the brake. The acceleration slip control is performed by adjusting the intake air amount.

That is, the acceleration slip control device 1 outputs a control signal to the drive motor 46 of the sub-throttle valve 44 provided in the intake pipe 42 of the engine for applying the driving force to the drive wheels 7 and 8. By closing, the main throttle valve 49 linked to the accelerator pedal 48 is prevented from being excessively slipped due to the rapid opening.

The throttle position sensor 49a includes an idle switch that issues an ON signal when the main throttle valve 49 is fully closed, and the acceleration slip control circuit 40 outputs a signal corresponding to the opening degree in order to execute map processing and the like described later. Is output to.

The structure of the acceleration slip control circuit 40 will be described with reference to FIG.

The acceleration slip control circuit 40 includes a CPU 40
a, ROM 40b, RAM 40c, backup RAM
40d and the like are configured as a logical operation circuit, and an input port 40f and an output port 4 are provided via a common bus 40e.
It is connected to 0g and inputs and outputs with the outside.

The detection signals from the pedal switch 34, the engine speed sensor 38, the acceleration sensor 39, and the throttle position sensor 49a described above are directly applied to the left / right side.
The detection signals of the rotation speed sensors 35 to 37 for the right rear wheel are transmitted from the input port 40f to the CP via the waveform shaping circuit 40h.
It is input to U40a.

Further, the drive circuits 40i-4 of the first to third solenoid valves 18, 21, 22 described above, the pump drive motor 26 and the sub-throttle valve drive motor 46.
0n is also provided, and the CPU 40a outputs a control signal to the drive circuits 40i to 40n via the output port 40g. Further, a control program for executing processing for preventing the vehicle from moving backward when the vehicle stops on an uphill road is input to the CPU 40a, as described later. That is, when the driving force transmitted from the engine to the left and right rear wheels 7 and 8 as driving wheels is stopped on an uphill road, when the driving force is smaller than the backward force acting on the vehicle, the braking force is applied.

The processing executed by the CPU 40a will be described with reference to FIG.

The CPU 40a repeatedly executes the processing of S1 to S8 shown in FIG. 4 at predetermined time intervals. In FIG. 4, in step S1 (hereinafter “step” is omitted), it is determined whether or not the vehicle is in a stopped state based on the detection signals from the rotation speed sensors 35 to 37. When it is determined in S1 that the vehicle is stopped, the process proceeds to S2, and the slope angle (gradient θ) of the slope is calculated based on the detection signal from the acceleration sensor 39. As shown in FIG. 5, the inclination angle θ of the slope is determined by measuring the force gx acting on the rear side of the vehicle by the acceleration sensor 3
It is determined by the detection by 9. That is, the slope angle (slope θ) of the slope is obtained by the following equation (1) (slope angle detecting means).

Θ = sin ⁻¹ (gx) (1) Then, in S3, the estimated value of the retreat force R that causes the vehicle to retreat by gravity according to the slope angle of the slope is calculated by the following equation (2). Calculate (backward force estimating means).

R = g · sin θ · W (2) (where g is gravitational acceleration, W is total vehicle weight, and RO is respectively
It is stored in M40b. Next, in S4, it is determined whether or not the vehicle is in a road surface state capable of climbing a slope against the backward force R calculated in S3. That is, when R <μ · W _R (where μ is the friction coefficient of the road surface and W _R is the rear wheel axle load), it is determined that the vehicle can climb a slope, and the routine proceeds to S5.

The coefficient of friction μ is obtained by detecting the rotational speed difference between the front wheel and the rear wheel caused by slip, for example, from the detection signals from the left front wheel rotational speed sensor 36 and the rear wheel rotational speed sensor 37, and based on this. It is calculated. Rear wheel axle load W
_R is stored in the ROM 40b in advance.

At the next step S5, an estimated value of the minimum driving force required to stop the vehicle on a slope having an inclination angle θ, that is, the driving force (torque) D transmitted from the engine to the left and right rear wheels 7 and 8 as driving wheels. Is calculated by the following equation (3) (driving force estimating means).

D = MIN [f (θ_MIN, NE) ・ e ・ I_G・ I_D/ R, μ ・ W_R] (3) (However, θ_MINIs the opening of the throttle valves 44 and 49
The smaller throttle opening, NE is the engine speed, e
Is the torque ratio of the torque converter, I_GIs the gear ratio, I_DIs
(Diff ratio, r is the tire diameter) Note that the torque transmitted to the road surface is limited, so drive
The maximum value of force D is μ ・ W _RAnd

Subsequently, in S6, it is determined whether or not the vehicle can be stopped or started on a slope having an inclination angle θ.
That is, when the driving force D and the retreating force R are compared and D <R, the retreating force R is larger than the driving force D, so it is determined that the vehicle moves backward without stopping on a slope.

In this case, the process proceeds to S7 and the vehicle is stopped on a slope using the rear brake so that the vehicle does not move backward. At this time, as shown in FIG. 6, the left and right rear wheels 7 and 8 are
A braking force B as a braking force according to the difference between the reverse force R and the driving force D transmitted to the left and right rear wheels 7 and 8 is added (a braking force adding means).

That is, in this embodiment, the accumulator 2 is operated by operating the solenoid valves 18, 21, 22 described above.
8 and the control input port 20a are connected to each other, and the piston 20c of the acceleration slip control displacement control valve 20 is operated to increase the hydraulic pressure from the output port 20f to the left.
The right rear wheel wheel cylinders 9 and 10 are supplied. As a result, the braking force acts on the left and right rear wheels 7 and 8, and the vehicle stops on the slope.

When the vehicle is traveling in S1 or when it is determined that climbing is physically difficult in S4, the series of processes is terminated without executing the processes of S5 to S7.

Further, in S6, D> R and the driving force D is larger than the retreating force R. Therefore, when the vehicle does not retreat on a slope, the process proceeds to S8 and the braking force B is made zero.

As shown in FIG. 7A, when the vehicle travels on a slope, the vehicle is temporarily stopped in the middle of the slope and then the vehicle is started. When the vehicle is started, the accelerator pedal 48 is operated to open the main throttle valve 49. The degree changes as shown in FIG. 7 (B). That is, the opening of the main throttle valve 49 is fully closed while the vehicle is stopped, and gradually opened when the vehicle is started.

Therefore, the driving force (torque) of the engine
Changes as shown in FIG. 7 (C). Therefore, while the main throttle valve 49 is closed, the driving force of the engine becomes smaller than the retreat force R described above.

When the braking force B is applied in S7, the braking force B is applied to the left / right rear wheel 7, while the driving force of the engine is lower than the reverse force R, as shown in FIG. 7 (D). 8 is added. As a result, the driving force of the left and right rear wheels 7 and 8 does not fall below the reverse force R even when the vehicle is stopped, as shown in FIG. 7 (E), and the vehicle is prevented from moving backward when the vehicle starts on a slope.

As described above, the backward force R corresponding to the slope angle θ of the slope is used to generate the braking force. Therefore, when the vehicle may move backward on the slope, the left and right rear wheels 7 and 8 are always braked. It is possible to prevent the vehicle from moving backward due to the force.

Next, a modification of the present invention will be described.

In the above embodiment, the existing acceleration sensor 39 is used.
Although the slope angle θ of the slope is obtained based on the detection signal of, the present invention is not limited to this, and other detection means may be used.

For example, as shown in FIG. 8, a pair of liquid level sensors 5 are provided inside a fuel tank 50 mounted at the rear of the vehicle.
1, 52 are provided, and the slope angle θ of the slope is calculated based on the detection signals of the liquid level sensors 51, 52. That is, one liquid level sensor 51 is provided on the front side of the fuel tank 50,
The other liquid level sensor 52 is provided on the rear surface side of the fuel tank 50.

Therefore, when the vehicle stops on a slope, since the liquid level in the fuel tank 50 is horizontal, the liquid level position on the front side of the fuel tank 50 becomes low and the liquid level position on the rear side of the fuel tank 50 becomes high. Become. Therefore, the liquid level sensors 51, 52
The slope angle θ of the slope is calculated by the following equation (4) based on the difference between the detection signals output from

Θ = tan ⁻¹ (b / a) (4) (where a is the difference between the liquid surface positions and b is the liquid surface sensors 51 and 52)
When calculating the inclination angle θ of the slope using the liquid level sensors 51 and 52, the liquid level in the fuel tank 50 is stabilized in a horizontal state after the vehicle stops on the slope. The calculation is performed after waiting for a predetermined time.

Instead of providing the liquid level sensors 51, 52, an inclinometer for detecting the inclination angle in the front-rear direction of the vehicle may be provided, and the detection signal from the inclinometer may be calculated as the inclination angle θ. .

As another modification of the above embodiment, when the vehicle is likely to move backward on a slope, the left and right rear wheels 7, 8 are
Instead of adding braking force to the left and right rear wheels 7,
It is also possible to adopt a configuration in which the driving force of the engine is added to 8.

In this case, in S7, the idle speed control valve (not shown) is controlled to raise the idle speed of the engine above the normal speed and the driving force transmitted to the left and right rear wheels 7, 8 is increased. increase. That is, FIG.
As shown in FIG. 6, the driving force Di to be increased is the difference (Di = R−) between the reverse force R corresponding to the slope angle θ of the slope and the driving force D transmitted from the engine to the left and right rear wheels 7 and 8 when the vehicle is stopped. D).

Therefore, the CPU 40a, based on the detection signal from the engine speed sensor 38, drives the driving force D + D.
The idle speed of the engine is increased so that i is balanced with the reverse force R. As a result, if you operate the operation lever of the automatic lance mission to the drive position,
The vehicle does not need to step on the brake pedal 34a to incline
You can stop on a slope regardless of the size of the car.

[0057]

As described above, in the slope stop apparatus according to the present invention, when the vehicle stops on a slope, the deviation between the backward force estimated by the backward force estimating means and the driving force estimated by the driving force estimating means. By adding a braking force that balances the retreat force based on, the vehicle can be stopped on a slope without the driver operating the brake. Furthermore, since a braking force that balances the backward force according to the slope angle of the slope is added, the vehicle can be reliably stopped on the slope even if the slope angle of the slope changes, and the reliability of the device is further enhanced. ing. Also, when it is estimated that the driving force that balances the backward force according to the slope angle of the slope is transmitted to the drive wheels, the braking force can be released and the vehicle can start. It has features such as improved safety.

[Brief description of drawings]

FIG. 1 is a principle diagram of the present invention.

FIG. 2 is a schematic configuration diagram of an embodiment of a slope stop apparatus according to the present invention.

FIG. 3 is a schematic configuration diagram of an embodiment of a sloped vehicle stopping device according to the present invention.

FIG. 4 is a flowchart illustrating a process executed by a CPU.

FIG. 5 is a diagram showing a tilted state of the vehicle.

FIG. 6 is a diagram for explaining force balance when a braking force is applied to the drive wheels.

FIG. 7 is a diagram illustrating a change in throttle opening, a change in engine driving force, a change in braking force or an increased engine driving force, a change in engine driving force and an increase in engine braking force when the vehicle stops or starts on a slope. 6 is a graph showing a change in resultant force with respect to the driving force of the engine.

FIG. 8 is a diagram for explaining a modified example of the means for detecting the slope angle of the slope.

FIG. 9 is a diagram for explaining a balance of forces when the engine driving force is increased to act on the driving wheels.

[Explanation of symbols]

 1 Acceleration Slip Control Device 2 Brake Master Cylinder 3,4 Front Wheel 5,6,9,10 Wheel Cylinder 7,8 Rear Wheel 11 Hydraulic Source 12 Anti-Skid Control Hydraulic Circuit 13 Acceleration Slip Control Hydraulic Circuit 18 First Solenoid Valve 18 20 Capacity control valve for acceleration slip control 21 Second solenoid valve 22 Third solenoid valve 27 Pump 28 Accumulator 35 Right front wheel rotation speed sensor 36 Left front wheel rotation speed sensor 37 Rear wheel rotation speed sensor 38 Engine rotation speed sensor 39 Acceleration sensor 40 Acceleration Slip control circuit 40a CPU 44 Sub throttle valve 48 Accelerator pedal 49 Main throttle valve 50 Fuel tank 51, 52 Liquid level sensor

Claims (1)

[Claims] 1. An inclination angle detecting means for detecting an inclination angle of a slope, a reverse force estimating means for estimating a reverse force acting on a vehicle based on the angle detected by the inclination angle detecting means, and a drive wheel of the vehicle. A driving force estimating means for estimating the transmitted driving force from the engine; a backward force estimated by the backward force estimating means and a driving force estimated by the driving force estimating means when the vehicle is stopped on a slope. And a braking force adding means for adding a braking force that balances the retreating force based on the deviation of the slope stopping device.