JP2000203415A - Automatic stop control device for engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To dispense with additional mounting of a high-cost special purpose apparatus and to secure proper brake performance after an automatic stop of an engine. SOLUTION: This automatic stop control device comprises a brake device 7 provided with a brake booster 70 to assist operation of a brake pedal 50 by utilizing the negative pressure of an engine 1; and a control means 2 to execute control to stop the engine 1 when a specified condition is satisfied during a stop of an automobile. In this case, a device having a function to maintain a brake operation state regardless of the presence of a feed of a negative pressure from an engine 1 when the brake device 7 is operated is used as the brake booster 70. The control means 2 is constituted such that when in a case of the engine 1 being brought into a stop, the brake device 7 is in an actuating state, control to maintain the actuating state of the brake device 7 by the brake booster 70 prior to a stop of the engine 1 is executed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control system for automatically stopping an engine of a vehicle when the vehicle is stopped.

[0002]

As is well known, for example, when driving in an urban area by car,
When waiting for a signal for a relatively long time, it is desirable to temporarily stop the engine of the automobile to improve the fuel efficiency and protect the environment by reducing exhaust gas. For this reason, conventionally, as a device for meeting such a demand, various devices have been proposed that automatically stop the engine of a vehicle when certain conditions are satisfied when the vehicle stops. As conditions for automatically stopping the engine, it is generally selected that the vehicle speed is zero or as close to zero as possible and that the parking brake is operating. However, when waiting for a traffic light, etc., the foot brake is frequently used instead of the parking brake. Therefore, the foot brake is actually operated instead of the parking brake, and the car stops. In such a case, it is preferable that the engine be automatically stopped.

[0003] However, a foot brake is generally configured as a brake device using a brake booster utilizing negative pressure of an engine. Therefore, if the engine stops automatically when the vehicle is stopped using the foot brake, the negative pressure in the brake booster will decrease as the brake pedal is repeatedly depressed, and the braking performance of the foot brake will decrease. Occurs.

[0004] As a means for solving such a problem,
Conventionally, as described in, for example, JP-A-59-194050, there is a means for driving an electric negative pressure pump when the engine is automatically stopped to increase the negative pressure in the brake booster. However, in this conventional means, since an expensive electric negative pressure pump needs to be mounted on the vehicle, there is a problem that the cost of the vehicle is increased correspondingly. Further, the burden on the battery power supply used for driving the negative pressure pump also increases.

The present invention has been devised in view of such circumstances, and it is possible to provide an appropriate brake performance even after an automatic stop of the engine without providing additional expensive dedicated equipment. An object of the present invention is to provide an automatic stop control device for an engine that can be secured.

[0006]

DISCLOSURE OF THE INVENTION In order to solve the above problems, the present invention employs the following technical means.

An automatic stop control device for an engine provided by the present invention includes a brake device having a brake booster that assists the operation of a brake pedal by utilizing a negative pressure of the engine, and a constant value when the vehicle is stopped. Control means for executing control for stopping the engine when a condition is satisfied, wherein the brake booster is operated when the brake device is operating. A function capable of maintaining the brake operation state irrespective of the presence or absence of a negative pressure supply from the engine, and the control means operates the brake device when the engine is stopped. In this state, the brake booster is operated by the brake booster prior to stopping the engine. Characterized in that it is configured to perform control to maintain.

In the present invention, when a certain condition is satisfied when the vehicle is stopped and the engine is automatically stopped,
When the brake device is in the operating state, the control means controls the brake booster prior to the automatic stop of the engine, and the brake booster maintains the operating state of the brake device. The operating state of this brake device is
It is maintained even after the engine stops and the negative pressure supply from the engine to the brake booster is stopped. Therefore, unlike the conventional case, the present invention can sufficiently secure the braking performance of the vehicle even after the automatic stop of the engine without using an electric negative pressure pump. As a result, in the present invention, it is possible to reduce the cost of the vehicle by the amount that the negative pressure pump is not required, and it is also possible to reduce the load on the battery power supply.

Other features and advantages of the present invention will become more apparent from the following description of embodiments of the present invention.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be specifically described below with reference to the drawings.

FIG. 1 is an explanatory diagram showing an example of an automatic engine stop control device according to the present invention.

The automatic stop control system for an engine according to the present embodiment includes an electronic control unit 2 for controlling the operation of an engine 1 mounted on an automobile, and a brake device 7.

The electronic control unit 2 includes a vehicle speed sensor 3,
An accelerator switch 4 that is turned on when the accelerator pedal 40 is operated, a foot brake switch 5 that is turned on when the foot brake pedal 50 is operated, and a parking brake switch 6 that is turned on when the parking brake lever 60 is operated are connected. I have. Although not shown in the drawings, devices and switches other than the above-described sensors and switches are also connected to the electronic control unit 2, and various data necessary for controlling the operation of the engine 1 are electronically controlled. It is configured to be input to the unit 2. The electronic control unit 2 includes a CPU, a memory connected thereto, and the like, and corresponds to an example of a control unit according to the present invention.

The brake device 7 is operated by depressing a foot brake pedal 50, and includes a brake booster 70, a master cylinder 71 connected to the brake booster 70, and a master cylinder 71.
1 is provided with a hydraulic piping system (not shown) for supplying the brake fluid pressure generated in 1 to a predetermined brake actuator. The brake booster 70 is connected to an intake path such as a surge tank 10 or an intake manifold provided on the intake side of the engine 1 by a pipe, so that the booster of the foot brake pedal 50 utilizing the negative pressure of the engine 1 is used. It functions as a device.

However, the brake booster 70 is a so-called brake booster provided with an electromagnetic valve having an electromagnetic valve 70a therein, and when the foot brake pedal 50 is depressed and the brake device 7 is operated.
By operating the solenoid valve 70a, a function of locking the brake operation state and continuing the state is provided irrespective of whether or not the negative pressure is subsequently supplied from the engine 1. A brake booster having such a function is intended to prevent the so-called engine stall and the vehicle from retreating by maintaining the operation state of the brake until the accelerator pedal is depressed when starting the vehicle on a slope. For example, Japanese Utility Model Application Laid-Open No. 60-13854 and Japanese Patent Publication No. Hei 5-77546.
This corresponds to a brake booster described in, for example, Japanese Unexamined Patent Publication (Kokai) No. H10-209. As the brake booster 70, a conventionally known brake booster described in the above gazette or the like can be used, and a detailed description of a specific structure thereof is omitted.
The schematic structure is such that a constant pressure chamber and a variable pressure chamber provided inside the brake booster 70 communicate with each other via a communication passage, and the communication passage is opened and closed by a solenoid valve 70a. The constant-pressure chamber is a chamber that receives a supply of negative pressure from the engine 1, while the variable-pressure chamber is a chamber into which air is introduced. The constant-pressure chamber and the variable-pressure chamber are diaphragms having an input shaft and an output shaft. Is divided by
When the foot brake pedal 50 is operated, the brake device 7
When the solenoid valve 70a is closed when is operated, the operation of the diaphragm having the input shaft and the output shaft is fixed regardless of whether or not the negative pressure is supplied to the constant-pressure chamber. Numeral 70 maintains the operating state of the brake device 7.

The electronic control unit 2 is configured to execute control for automatically stopping the engine 1 based on a program stored in the memory. More specifically, the conditions for the electronic control unit 2 to automatically stop the engine 1 include, for example, the vehicle speed detected by the vehicle speed sensor 3 is zero and the brake switches 5 and 6
Is required to continue for a certain period of time, and program data to that effect is stored in the memory of the electronic control unit 2. Of course, in the present invention, in addition to the above conditions, the cooling water temperature,
Items such as the battery voltage and the engine speed may also be included in the conditions for automatically stopping the engine 1. However, in the engine automatic stop control device of the present embodiment, when the engine 1 is automatically stopped and the foot brake switch 5 is turned on, the electronic control unit 2 operates the brake booster prior to the stop of the engine 1. The control for closing the solenoid valve 70a of the 70 is executed.

Next, the operation of the automatic engine stop control device and the operation procedure of the electronic control unit 2 will be described with reference to the flowchart shown in FIG.

First, the vehicle in the running state stops and the vehicle speed becomes zero, and then the brake is applied for a certain period of time, so that the above-mentioned certain condition for stopping the engine is satisfied. And (S1: YES),
At that time, the electronic control unit 2 checks whether the foot brake switch 5 is on (S2). When the foot brake pedal 50 is depressed, the brake device 7 is depressed.
Is in the operating state, the foot brake switch 5 is on (S2: YES). Accordingly, in this case, the electronic control unit 2 controls the solenoid valve 7 of the brake booster 70.
0a is closed, and then the engine 1
Is executed (S4, S4). As a result, fuel can be saved.

According to such a series of controls, since the operating state of the brake device 7 is locked before the engine 1 is stopped, the supply of the negative pressure into the brake booster 70 after the stop of the engine 1 is performed. Even if the operation is not performed, the vehicle can be appropriately stopped using the brake device 7. After the automatic stop of the engine, for example, when the accelerator pedal 40 is depressed by the driver and the accelerator switch 4 is turned on, the engine 1 is restarted under the control of the electronic control unit 2 and then the electromagnetic force of the brake booster 70 is released. By operating the valve 70a in the open state, the brake state by the brake device 7 may be released.

On the other hand, when certain conditions for automatically stopping the engine 1 are satisfied (S1: YES),
When only the parking brake is used, the foot brake switch 5 is in the off state (S2: N
O). Therefore, in this case, the electronic control unit 2 immediately executes control to stop the engine 1 (S
4). After the automatic stop of the engine 1, when the accelerator switch 4 is turned on or when the parking brake switch 6 is turned off by releasing the parking brake, the engine 1 is controlled by the electronic control unit 2. Should be restarted.

The specific configuration of each part of the automatic engine stop control device according to the present invention is not limited to the above-described embodiment, and various design changes can be made. For example, the conditions for automatically stopping the engine when the car is stopped include:
Various conditions can be considered, and the specific contents are not particularly limited.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an example of an automatic engine stop control device according to the present invention.

FIG. 2 is a flowchart illustrating an example of an operation procedure when performing automatic stop control of an engine.

[Explanation of symbols]

 Reference Signs List 1 engine 2 electronic control unit (control means) 3 vehicle speed sensor 4 accelerator switch 5 foot brake switch 6 parking brake switch 7 brake device 70 brake booster 70a solenoid valve

Continued on the front page F term (reference) 3D048 BB23 BB57 CC26 HH26 HH42 HH66 HH67 HH79 KK09 QQ11 RR00 RR01 RR35 3G093 BA22 CB00 DA01 DA05 DB06 DB15 DB19 EB04 EC01

Claims (1)

[Claims] 1. A brake device comprising a brake booster for assisting operation of a brake pedal by utilizing a negative pressure of an engine, and control for stopping an engine when certain conditions are satisfied when the vehicle is stopped. Control means for executing an automatic stop control of the engine, wherein the brake booster is configured to determine whether or not a negative pressure is supplied from the engine when the brake device is operating. A function having a function capable of maintaining the brake operation state is used regardless of whether the brake device is in the operation state when stopping the engine. The brake booster is configured to execute control for maintaining the operating state of the brake device. The symptom, the automatic stop control device for an engine.