JPH11314541A - Automatic brake device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an automatic brake device capable of controlling brake force even in an automatic brake actuation mode. SOLUTION: This automatic brake device uses an intake negative pressure actuation type brake booster 410 consisting of a first chamber 412 for introducing intake negative pressure and a diaphragm 413. A three-way electromagnetic change-over valve 411 is provided to a pile line for communicating the first chamber 412 with an intake pipe 414 in an engine 421. In a normal mode, the first chamber 412 is communicated with atmosphere. In an automatic brake actuation mode, the three-way electromagnetic change-over valve 411 is switched, communicating the first chamber 412 with the intake pipe 414. In addition, the intake pipe 414 is provided with a throttle valve, so called an electrically controlled throttle 420, for controlling closing motion by means of an electric motor. In the automatic brake actuation mode, the electrically controlled throttle 420 controls the opening of the throttle valve. The resulting control for the intake negative pressure entails fine control for brake force generated from the brake booster 410.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for automatically controlling a brake of a vehicle, and more particularly to an automatic brake apparatus suitable for controlling a traveling speed of an automobile.

[0002]

2. Description of the Related Art Improving the safety of automobiles is a constant proposition. For this reason, various proposals have been made for equipment for ensuring safety. ACC (Ada) which controls both power and runs while automatically adjusting the inter-vehicle distance to an appropriate value.
ptive Cruise Control) device, or an automatic brake device that automatically activates the brake when the distance between vehicles becomes dangerous, such as when following a traffic jam, or when an obstacle suddenly pops out. Proposed.

[0003] Further, when the vehicle enters a dangerous area where it may collide with an obstacle due to, for example, an inattentive driving or a drowsiness driving, a device for preventing collision and a device for protecting occupants are provided. Various proposals have also been made for a technique for controlling the apparatus.
No. 67 proposes an automatic brake device that detects an obstacle and automatically applies a brake when a possibility of contact occurs.

[0004] The automatic brake device (prior art) disclosed in this publication is connected to an intake pipe of an engine and has a first chamber in which intake pipe pressure (intake negative pressure) is introduced and a first chamber in which atmospheric pressure is introduced. It has a brake booster which has a booster function by the differential pressure between the first chamber and the second chamber. When the brake is operated, the throttle valve (throttle valve) of the engine is turned on. The brake is activated by introducing atmospheric pressure into the second chamber after the fully closed state.

FIG. 5 is a conceptual diagram of a brake booster according to the prior art, which will be described more specifically below. First, the brake booster here means that the driver (driver) requires less brake pressing force, which provides sufficient braking force with a light operating force and makes it easy to make fine adjustments near the tire grip limit. Is used to ensure that

A brake booster 401 shown in FIG. 5 is of a vacuum servo type generally used in a normal vehicle, and utilizes a negative pressure of an intake air of an engine to generate a pedaling force using the negative pressure as a power source. It acts to increase and communicate to the master cylinder 400.

When the engine is idling, the pressure in the intake pipe 405 is about 34.
It drops to 7kPa (about 1 / 3atm, about 500boost).
Therefore, the first chamber 402 of the brake booster 401 is connected to the intake pipe 405 of the engine so that the inside thereof has a negative pressure. At this time, the first chamber 402 is connected to the intake pipe 405 of the engine via the check valve 404.

Here, the check valve 404 is opened only when the negative pressure in the first chamber 402 is higher than the pressure in the intake pipe 405, and the air flows from the first chamber 402 to the intake pipe 405. As a result, the negative pressure in the first chamber 402 becomes the pressure (negative pressure) when the inside of the intake pipe 405 becomes the lowest in the operating state until the brake pedal is depressed.
Will be kept.

First, when there is no depressing operation of the brake pedal shown in FIG.
3 communicates and has the same negative pressure. Next, FIG.
In the case where there is a stepping operation shown in (b), the first chamber 402 and the second chamber 403 are isolated by the valve mechanism around the operating rod 407, the atmosphere is introduced into the second chamber 403, and the atmospheric pressure is reduced. Become.

Therefore, the negative pressure in the first chamber 402 and the second chamber 4
The diaphragm 406 is moved by the difference from the atmospheric pressure in the cylinder 03, and the force due to the pressure difference at this time is added to the brake pressing force by the driver and transmitted to the master cylinder 400. Therefore, a large braking force is applied with a small braking force. It is done.

[0011]

In the above prior art, no consideration is given to the control of the braking force during the automatic braking operation. When the automatic braking is performed, a substantially constant braking force is obtained regardless of the situation. There is a problem that it is only activated and cannot be applied to an ACC device that requires fine control of the braking force or an automatic brake control during traffic-following traveling.

That is, in the conventional brake booster,
A check valve (check valve) is attached to the passage connecting the intake pipe and the brake booster. This check valve opens only when the pressure in the first chamber becomes higher than the pressure in the intake pipe, and connects the first chamber to the intake pipe. Therefore, the negative pressure in the first chamber is reduced by the negative pressure in the first chamber. Is maintained at the lowest intake negative pressure during the operation state before the atmospheric pressure is introduced.

Since the check valve is provided, the braking force when the automatic brake is actuated is determined by the value of the intake negative pressure. As a result, fine control of the braking force, such as a slight release of the brake, cannot be performed. It is.
An object of the present invention is to provide an automatic brake device that can control a braking force even when an automatic brake is operated.

[0014]

The object of the present invention is to provide a vehicle state detecting means for detecting a running state of a vehicle, a running environment detecting means for detecting an environment around the vehicle, and a vehicle state detecting means. Automatic brake control means for determining whether or not to apply an automatic brake based on vehicle state data fetched from the means and driving environment data fetched from the driving environment detecting means. A brake booster powered by negative pressure,
A passage switching means for selectively communicating the negative pressure chamber of the brake booster with either the intake pipe of the engine or the atmosphere; and a throttle valve for controlling the throttle valve opening of the engine independently of the operation state of the accelerator pedal. Opening / closing means, wherein the automatic brake control means controls the passage switching means at the time of automatic braking operation to switch the negative pressure chamber of the brake booster from the atmosphere into the intake pipe of the engine, and This is achieved by controlling the valve opening / closing means so that the magnitude of the braking force is controlled.

The throttle valve opening / closing means serves to change the negative pressure of the intake air of the engine and to change the magnitude of the negative pressure applied to the booster when the automatic brake is operated. Therefore, the magnitude of the braking force can be controlled at the time of the automatic braking operation, and the driving safety can be sufficiently secured by applying to the ACC device or the automatic braking control at the time of running following a traffic jam.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an automatic brake device according to the present invention will be described in detail with reference to the illustrated embodiments.
FIG. 1 shows a basic configuration of an embodiment of the present invention. In this embodiment, a vehicle state detecting unit 1, a traveling environment detecting unit 2, an automatic brake control unit 3, and an automatic brake operating unit 4 are included. It is composed of four types of means.

The vehicle state detecting means 1 includes a speed, an acceleration, an accelerator depression amount, an accelerator opening / closing speed, a brake depression amount, a brake depression speed, an engine rotation speed, a drive shaft torque, a gear ratio, a steering angle, and electric components of the vehicle. It functions to detect various vehicle state data such as the operation state of the control switch.

The traveling environment detecting means 2 includes a distance between vehicles and a relative speed with respect to a preceding vehicle (a vehicle traveling ahead of the own vehicle),
It functions to detect various traveling environment data such as obstacles, curve curvature, gradient, μ (coefficient of friction of road surface), visibility, traffic regulation information, traffic congestion information, speed and acceleration of other vehicles.

The automatic brake control means 3 determines whether or not to activate the automatic brake based on the vehicle state data supplied from the vehicle state detection means 1 and the traveling environment data supplied from the traveling environment detection means 2. When it is determined that the brake should be operated, a brake operation command is generated.

The automatic brake actuating means 4 is a throttle opening / closing means in which the opening of the throttle valve can be changed by an actuator (drive mechanism) such as an electric motor independently of the operation of the accelerator pedal, that is, a so-called electronic throttle (electronically controlled throttle). (A control-type throttle valve), whereby the opening of the throttle valve is controlled in accordance with a control signal supplied from the automatic brake control means 3 so that the intake negative pressure of the engine can be controlled.

Therefore, when the automatic brake is operated, the negative pressure supplied to the intake negative pressure operated type brake booster is controlled,
As a result, a predetermined braking force is obtained based on the brake operation command of the automatic brake control means 4. In addition, the gear ratio of the transmission was changed, and the change in engine speed was used to control the intake negative pressure.
This also allows the braking force to be controlled.

At this time, within a predetermined period of time, the speed change control is performed within a predetermined range of the number of gears for a stepped transmission such as a gear type transmission, and within a predetermined range of a reduction ratio change range for a continuously variable transmission. This also serves to prevent the ride comfort from deteriorating due to the shift shock. Furthermore, when the automatic brake is operated, the supply of fuel to the engine is cut off, and control is performed so that the engine brake is sufficiently effective.

Therefore, according to this embodiment, the negative pressure in the intake pipe of the engine is finely controlled by the function of the electronically controlled throttle, and as a result, the magnitude of the braking force during the automatic braking operation can be finely controlled. Become AC
The present invention can be applied to the C apparatus or to traffic congestion cruise control.

Next, a specific embodiment of the present invention will be described with reference to FIG. FIG. 2 shows a hardware configuration according to an embodiment of the present invention. In this embodiment, as shown in FIG. 2, a first chamber 412 into which intake negative pressure is introduced, and a diaphragm 41 as a brake booster.
3 is used.

The first chamber 41 of the brake booster 410
2 is selectively switched to communicate with the atmosphere and one of the intake pipes 414 of the engine 421 via a three-way electromagnetic switching valve 411.
By the function of 11, it is usually connected to the atmosphere side,
At the time of automatic brake operation, the intake pipe 41 of the engine 421
4 is connected.

In this embodiment, first, the inter-vehicle distance and the relative speed, which are one type of traveling environment data, are obtained by the radar device 200 and input to the ACC / C / U (control unit) 300.

Here, for the sake of simplicity, only the radar device 200 is shown as the traveling environment detecting means 2 (FIG. 1), but a camera mounted on the vehicle, a navigation system, road-to-vehicle communication, vehicle-to-vehicle communication, etc. Obtained from, obstacles, curve curvature, gradient, μ, visibility, traffic regulation information, traffic congestion information, traveling environment data such as speed and acceleration of other vehicles,
The data is input to the ACC / C / U 300.

Although not shown, speed, acceleration, accelerator depression amount, accelerator opening / closing speed, brake depression amount, brake depression speed, engine speed, drive shaft torque are obtained from various sensors mounted on the vehicle. , Gear ratio, steering angle, operation switch status, etc.
The data is input to the ACC / C / U 300 as vehicle state data.

These data are transmitted to the communication device 30.
6, from the ACC / C / U 300 to another C / U 30
1 to 305, and furthermore, necessary data is mutually exchanged between the respective C / Us by the communication device 306.

Therefore, first, the driving force management C /
U301 determines whether or not to activate the automatic brake based on these data. If it is determined that the automatic brake is activated, U301 gives a command to the automatic brake C / U302, and thereby the three-way electromagnetic switching valve 411. Control.

When the automatic brake is not operated, the three-way electromagnetic switching valve 411 is connected to the first switch of the brake booster 410.
The chamber 412 is communicated with the atmosphere side, and functions to switch the state in which the first chamber 412 is communicated from the atmosphere side to the intake pipe 414 of the engine 421 during automatic braking operation.

When it is determined that the automatic braking operation is performed, the driving force management C / U 301
Is the electric throttle C / U303, engine C / U
U304, sends a command to the AT (CVT) C / U 305, and the throttle opening (throttle valve opening) by the electronically controlled throttle 420
, Control of fuel supply cut to the engine, and control of the transmission ratio of the transmission 422.
The pressure (negative pressure) in the intake pipe 414 is controlled.

Next, the operation of the brake booster 410 in this embodiment will be described with reference to FIG. First, when the driver does not depress the brake pedal, the first chamber 412 is communicated to the atmosphere by the three-way electromagnetic switching valve 411 as shown in FIG. The inside of one room 412 remains at the atmospheric pressure,
Therefore, no differential pressure is applied to the diaphragm 413. Therefore, at this time, as shown in FIG.
The piston of No. 5 does not move, and the brake does not operate.

Next, when the driver depresses the brake pedal or when the automatic brake is activated, the operation shown in FIG.
As shown in (b), the three-way electromagnetic switching valve 411 is switched. As a result, the first chamber 412 communicates with the intake pipe 414, and the inside of the first chamber 412
Negative pressure (a negative pressure of intake air).

Then, a force is generated in the diaphragm 413 due to the difference between the negative pressure in the first chamber 412 and the atmospheric pressure, and the piston of the master cylinder 415 is pushed, generating a braking force.

As a result, first, when the driver depresses the brake pedal, it functions as a brake booster, and the force due to the pressure difference and the brake pedal force by the driver are transmitted to the master cylinder 415, and the increased braking force is applied. Therefore, the servo function is the same as that of the conventional brake booster 401.

On the other hand, when the automatic brake is operated, the function of automatically applying the brake is obtained literally.
In this embodiment, the electronically controlled throttle 4
Since the throttle opening is controlled by 20 and the magnitude of the pressure (negative pressure) in the intake pipe 414 is controlled,
As a result, the strength of the braking force can be changed, and the degree of the braking effect can be delicately changed. Therefore, the present invention can be easily applied to an ACC device, traffic congestion cruise control, and the like.

Next, the operation of this embodiment will be described with reference to a time chart showing the control state of each C / U in FIG. FIG. 4 shows an operation example in a case where the preceding vehicle decelerates at time t1 and there is an interrupting vehicle at time t3 during traveling by ACC. While the vehicle is traveling by ACC, the radar device 200 detects the distance between the vehicle and the preceding vehicle, the relative speed is detected, and the vehicle state data and the traveling environment data are obtained from the detection results from various sensors mounted on the vehicle. Is input to each of the C / Us 300 to 305 and transmitted and received by the communication device 306.

Then, the driving force management C / U 30
The target driving force Ft is obtained by 1 and other C / U 300, 3
The target driving force data is sent to 02 to 305. When the target driving force is equal to or greater than the predetermined value Ft, as in the period from time t0 to time t1, the automatic brake C / U 302
The three-way electromagnetic switching valve 411 is set in the state shown in FIG. 3A, and the inside of the first chamber 412 of the brake booster 410 is kept at the atmospheric pressure.

Now, assuming that the preceding vehicle decelerates at time t1 and the target driving force becomes a value slightly smaller than the predetermined value Ft as in the period from time t1 to time t2, the automatic braking C / U302 is a three-way electromagnetic switching valve 411
Is switched to the state shown in FIG. 3B, and the first chamber 412 of the brake booster 410 is communicated with the inside of the intake pipe 414, and the first chamber 41
2. An intake negative pressure is introduced into 2.

At this time, the electronically controlled throttle C / U 303 starts controlling the throttle opening and changes the pressure in the intake pipe (negative intake pressure) to control the braking force generated by the brake booster 410. Then, the target driving force and the actual driving force are controlled to be the same.

Next, assuming that an interrupting vehicle enters at time t3, as shown in a period from time t3 to time t4, the target driving force is made much smaller than the predetermined value Ft.
As a result, a large braking force is required.

For this reason, the throttle opening is controlled by the electronically controlled throttle C / U 303, and a sufficient intake negative pressure is obtained at the rotation speed of the engine 421 determined at this time by the running speed of the automobile and the gear ratio of the transmission 422. If it is determined that the required braking force cannot be obtained,
At time t3, the transmission 422 is operated by the (CVT) C / U 305.
Control the braking force by changing the gear position, changing the gear ratio (gear ratio), increasing the engine speed, and bringing the required braking force to a state where the required braking force can be obtained. You do it.

At this time, the transmission 422 is set within a predetermined time.
In the case of a stepped transmission such as a general automatic transmission AT, the shift control is performed within a range of a predetermined number of gears, and in the case of a continuously variable transmission such as a CVT, the speed is controlled within a range of a predetermined gear ratio change width. As a result, as shown in the figure, the increase in the engine speed is changed from a stepped shape to a dull change, so that the deterioration of the riding comfort due to the shift shock is suppressed.

At this time, under the condition that the fuel cut condition is satisfied, at time t3, the fuel cut control by the engine C / U 304 is executed as shown in FIG. To

Therefore, according to this embodiment, the control of the engine speed and the control of the engine braking force are added to the control of the throttle opening in accordance with the required braking force, so that it is always flexible. It is possible to cope with the control of the braking force, and it is possible to control the running speed of the automobile more finely.

In this embodiment, the brake booster 410 used in this embodiment is composed of only the first chamber 412 and the diaphragm 413, and therefore, is different from the brake booster 401 of the prior art (FIG. 5). Since the valve has a simple structure such as eliminating the need for a valve, various advantages can be obtained, such as low cost, light weight, and high fuel efficiency can be expected while maintaining high reliability.

[0048]

According to the present invention, the braking force of the intake negative pressure actuated brake booster can be finely controlled, so that it can be easily applied to an ACC device and a traffic jam following control device. It is possible to provide an automatic brake device that can perform the automatic braking. Further, according to the present invention, since the brake booster has a simple configuration, the reliability is high,
Moreover, it is possible to easily provide an automatic brake device that can be easily reduced in cost and weight and can sufficiently improve fuel efficiency.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a basic configuration example of an automatic brake device according to the present invention.

FIG. 2 is a block diagram showing one embodiment of an automatic brake device according to the present invention.

FIG. 3 is an explanatory diagram of a brake booster in one embodiment of the present invention.

FIG. 4 is a timing chart for explaining the operation of one embodiment of the present invention.

FIG. 5 is an explanatory view of a conventional brake booster.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vehicle state detection means 2 Running environment detection means 3 Automatic brake control means 4 Automatic brake operation means 410 Brake booster 411 Three-way electromagnetic switching valve 412 First chamber 413 Diaphragm 414 Intake pipe

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI F02D 9/02 315 F02D 9/02 315B 29/02 301 29/02 301D 41/04 310 41/04 310G 41/12 330 41 / 12 330M 43/00 301 43/00 301H 301K

Claims (4)

[Claims] A vehicle state detecting means for detecting a running state of the vehicle; a traveling environment detecting means for detecting an environment around the vehicle; and vehicle state data taken from the vehicle state detecting means. An automatic brake control means for determining whether or not to apply an automatic brake based on the driving environment data taken from the driving environment detecting means. A booster; a passage switching means for selectively communicating a negative pressure chamber of the brake booster with either the intake pipe of the engine or the atmosphere; and controlling the throttle valve opening of the engine independently of the operation state of the accelerator pedal. A throttle valve opening / closing means for controlling, wherein the automatic brake control means controls the passage switching means at the time of automatic brake operation, and controls a negative pressure chamber of the brake booster. With switching from in the air into an intake pipe of the engine, and controls the throttle valve opening and closing means, an automatic braking device, characterized in that it is configured to control the magnitude of the braking force. 2. The automatic brake device according to claim 1, wherein the brake control means is configured to simultaneously use a change control of a gear ratio of a vehicle drive system when an automatic brake is operated. . 3. The automatic brake device according to claim 2, wherein the change in the reduction ratio of the vehicle drive system is executed within a predetermined change range within a predetermined time. . 4. The automatic brake device according to claim 1, wherein the brake control means is configured to perform a fuel cut control of an engine when the automatic brake is operated.