JPS622278Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic engine stop/start device applied to a vehicle having a brake booster.

An automatic engine stop/start device automatically stops the engine under predetermined stopping conditions when the vehicle stops at an intersection etc. while driving in a city, and then restarts the engine under predetermined starting conditions. This saves energy and improves exhaust emissions.

When a conventional engine automatic stop/start device is applied to a vehicle equipped with a brake booster, if the brake operation is repeated when the engine is automatically stopped, suction negative pressure is not introduced to the brake booster, so as the pressure inside the brake booster decreases. However, there was a problem in that the braking force decreased even with the same brake pedal force.

In view of these conventional problems, the purpose of this invention is to provide an engine that prevents a decrease in braking force by driving a vacuum pump when the pressure in the brake booster decreases even when the engine is automatically stopped. An object of the present invention is to provide an automatic stop/start device.

The present invention is used in a vehicle that is supplied with engine suction negative pressure and has a brake booster capable of supplying negative pressure with a vacuum pump, and includes a sensor group that outputs signals indicating the status of the engine and various parts of the vehicle. stop signal generating means for outputting an engine stop signal when it is determined that an engine automatic stop condition is satisfied based on the signal from the sensor group; and a stop signal generating means that outputs an engine stop signal when it is determined that the engine automatic stop condition is satisfied based on the signal from the sensor group; restart signal generating means for outputting an engine restart signal when determined;
In an automatic engine stop/start device having an engine stop means for stopping the engine in response to an engine stop signal and an engine restart means for restarting the engine in response to an engine restart signal, the negative pressure in the brake booster is reduced. a negative pressure detection means for detecting, a measuring means for measuring a predetermined time after the negative pressure detection means detects that the negative pressure in the booster is below a predetermined value; A pump that outputs a vacuum pump drive signal for driving a vacuum pump when a negative pressure detection means detects it, and stops outputting the vacuum pump drive signal when a predetermined time is measured by a measurement means. The present invention is characterized by comprising a drive signal generating means.

In order to solve the technical problems of the present invention, the vacuum pump may be driven at all times, regardless of the engine condition or the engine automatic stop/start device's control to automatically stop or restart the engine.
Vacuum pumps have problems not only in their durability but also in their large power consumption. Additionally, the vacuum pump is driven only when the engine is automatically stopped and the negative pressure in the brake booster is below a predetermined level, and the vacuum pump is only driven when the negative pressure in the brake booster exceeds a predetermined level. However, in that case, if the predetermined values of the negative pressure mentioned above for turning on and off the vacuum pump are not different, there is a risk that the pump will hunt. The configuration of the pressure detection means becomes complicated.

In contrast, in the present invention, the vacuum pump is continuously driven from when the brake booster pressure falls below a predetermined value until a predetermined time elapses after the brake booster pressure reaches a predetermined level or higher. Therefore, when using an automatic engine stop/start device, it is possible to prevent a decrease in the durability of the vacuum pump and to reduce power consumption with an even simpler configuration.

Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 1 shows the configuration of an embodiment in which the present invention is applied to a vehicle equipped with an automatic transmission.
is provided with an injector 3, a starter 5, and an igniter 7, and an automatic transmission 9 is connected to the output shaft of the engine 1. An intake manifold 11 and an exhaust manifold 13 are connected to each cylinder of the engine 1, and the intake manifold 11 is provided with a throttle valve 15 that is linked to an accelerator pedal. 52 are connected. The brake booster 52 is connected to a vacuum pump 54 via a check valve 53. Furthermore, a negative pressure switch 56 constituting negative pressure detection means is attached to a passage 55 connecting the check valve 51 and the brake booster 52, and the negative pressure switch 56 detects when the negative pressure in the passage 55 is below a predetermined level ( When the absolute value reaches ), it is energized and outputs a vacuum signal. 17 is a parking brake, and 19 is a display panel for the driver's seat.

The throttle valve 15 is provided with a throttle position sensor 15a that detects its opening degree, and an idle switch 15b that detects its fully closed state. The automatic transmission 9 includes a neutral range switch 21a that outputs a neutral range signal when the neutral range is selected, and a parking range switch 21b that outputs a parking range signal when the parking range is selected.
and a vehicle speed sensor 23 for detecting vehicle speed.

The parking brake 17 is provided with a parking brake switch 25 that outputs a parking brake signal when activated, and a stop lamp 27 is provided on the display panel 19 to indicate that the engine is stopped.
is provided. A start switch 20 is provided at a predetermined location, and is energized to restart the engine and output a start signal at that time.

The injector 3 is connected to a control circuit 37 through a fuel relay 31, the starter 5 through a starter relay 33, and the igniter 7 through an ignition relay 35. Further, the vacuum pump 54 and the stop lamp 27 are connected to the control circuit 37.

The control circuit 37 includes the ignition primary coil 7a of the igniter 7, the throttle position sensor 15a, the idle switch 15b, the start switch 20, the neutral range switch 21a, the parking range switch 21b, the parking brake switch 25, the door switch 39a, and the light switch 39.
b, air conditioner switch 39c, hydraulic switch 39
d, turn switch 39e, ignition switch 39f, water temperature sensor 39g, intake temperature sensor 3
9h, the intake air amount sensor 39i is connected.

FIG. 2 shows a detailed configuration example of the control circuit 37 shown in FIG. The control circuit 37 includes a central processing unit (CPU) 37a that controls various devices, a read-only memory (ROM) 37b in which various numerical values and programs are written in advance, and numerical values and flags of calculation processes are written in predetermined areas. Random access memory (RAM) 37c, A/D converter (ADC) 37d that converts analog input signals into digital signals, and input/output interface (I/C) 37e that receives various digital signals and outputs various digital signals. , and a bus line 37f to which each of these devices is connected. The program described below is in ROM37b.
is written in advance.

The I/O 37e receives an idle signal from the idle switch 15b, an engine speed signal from the ignition primary coil 7a, a start signal from the start switch 20, and a neutral range switch 21.
a, a parking range signal from the parking range switch 21b, a parking brake signal from the parking brake switch 25, a vehicle speed signal from the vehicle speed sensor 23, a door signal from the door switch 39a, and a light signal from the light switch 39b. , an air conditioner signal from the air conditioner switch 39c, an oil pressure signal from the oil pressure switch 39d, a turn signal from the turn switch 39e, and an ignition switch 39f.
The ignition signal from ADC3 is input.
A water temperature signal from the water temperature sensor 39g, an intake air temperature signal from the intake air temperature sensor 39h, an intake air amount signal from the intake air amount sensor 39i, and a position signal from the throttle position sensor 15a are input to 7d.
Then, the CPU 37a executes various calculations based on these various signals, and receives an ignition cut and ignition signal, a fuel cut and fuel injection signal, a starter drive signal, a stop lamp lighting and extinguishing signal, and a vacuum lamp signal from the I/D 37e. A pump drive signal is output.

Next, the operation of the automatic engine stop/start device configured as described above will be explained.

FIG. 3 shows the main routine executed by the control circuit 37. In step S1, the basic injection time is determined based on the intake air amount signal and the engine rotation speed signal, and the water temperature signal, intake temperature signal, throttle position signal, The basic injection time is corrected based on the ignition signal, etc. Next, in step S2, an automatic engine stop/start process is executed.

FIG. 4 shows one procedure of the engine automatic stop/start process. When the program shown in FIG. 4 is started, in step S21, it is determined based on the vehicle speed signal whether the vehicle speed is zero, or more precisely, whether the vehicle speed is below a predetermined value.In step S22, it is determined based on the engine speed signal. Based on this, it is determined whether or not the engine speed is equal to or lower than a predetermined idle speed, and the process proceeds to step S2.
3, the idle switch 15b is on based on the idle signal, that is, the throttle valve 1
In step S24, it is determined whether the parking brake 17 is operating based on the parking brake signal, and in step S25, it is determined whether the parking brake 17 is fully closed or not based on the parking range signal or neutral range signal. , P range, or N range is selected, and further, in step S26, other stop conditions for automatically stopping the engine are determined, such as no turn signal being issued and headlights being turned on. It is determined from the turn signal, light signal, air conditioner signal, water temperature signal, etc.

If all of these steps S21 to S26 are answered in the affirmative, it means that the engine automatic stop condition is satisfied, so in step S27,
The I/O 37e outputs a fuel cut signal and an ignition cut signal, which constitute an engine stop signal, to the fuel relay 31 and ignition relay 35, respectively, thereby deenergizing the igniter 7 and preventing high voltage from being supplied to the spark plug. At the same time, the injector 3 is deenergized so that it does not inject fuel,
Then, the engine 1 is stopped. Further, in step S27, a lighting signal is output from the I/O 37e to the stop lamp 27 to turn the stop lamp 27 on.

In step S28, the negative pressure in the brake booster 52 is switched to the negative pressure switch 5 installed in the passage 55.
Check by 6. That is, the booster 52
When the negative pressure within the booster 52 falls below a predetermined value (absolute value), the negative pressure switch 56 is activated and outputs a vacuum signal, so the state of negative pressure within the booster 52 is checked based on the presence or absence of the vacuum signal.

If the vacuum signal is output from the negative pressure switch 56, in step S29, a vacuum pump drive signal is supplied from the I/O 37e to the vacuum pump 54 to drive the pump 54. If the vacuum signal is not output, a negative determination is made in step S28, and the process jumps to step S33. In step S30, the brake booster 5
Check the negative pressure inside 2 again and turn on the negative pressure switch 56.
If it is de-energized and the vacuum signal is not output, an affirmative determination is made and the process proceeds to step S31. If the determination is negative, the process jumps to step S33.

In step S31, it is determined whether a predetermined time has elapsed since the negative pressure switch 56 was deenergized, that is, from the time when the negative pressure in the brake booster 52 reached a predetermined value or more (absolute value), and an affirmative determination is made. If so, the process advances to step S32, and if a negative determination is made, the process jumps to step S33.

In step S32, the vacuum pump drive signal is turned off to stop the vacuum pump 54.

In step S33, it is determined whether the start switch 20 is energized, and the process proceeds to step S3.
In step 4, other starting conditions for automatically starting the engine, such as that the engine is not rotating and that the parking brake 17 is operating, are determined. If all of these steps S33 and S34 are affirmatively determined, it means that the engine restart condition is satisfied, so in step S35,
The starter drive signal, fuel injection signal, and ignition signal that constitute the engine restart signal are transmitted from the I/O 37e to the starter relay 33 and fuel relay 3, respectively.
1. Output to the ignition relay 35, thereby driving the starter 5, energizing the igniter 7 and the injector 3, supplying high voltage to the spark plug at a predetermined timing, and injecting the injector 3.
Then, the engine 1 is restarted. In this step S35, the stop lamp 27 of the display panel 19 is also turned off.

In step S36, it is determined based on the engine rotational speed signal whether the engine has started restarting, that is, whether the engine rotational speed has exceeded a predetermined value. If an affirmative determination is made, step S37
Then, the starter drive signal is turned off to stop the starter 5, and the vacuum pump drive signal is also turned off to stop the vacuum pump 54.

In this way, the procedure shown in Fig. 4 checks the booster pressure in the brake booster 52 when the engine is automatically stopped, and if the booster pressure falls below a predetermined booster pressure (absolute value), the booster pressure is checked even though the engine is automatically stopped. In addition to driving the vacuum pump 54, the vacuum pump 54 is also driven for a predetermined period of time even after the negative pressure switch 56 is energized to maintain the negative pressure in the brake booster above a predetermined level. .

In the above embodiment, the automatic engine stop/start device is applied to a vehicle with an automatic transmission, but it goes without saying that the same configuration can be applied to a vehicle with a manual transmission. Also,
Although the negative pressure switch 56 is used as the negative pressure detection means, it is also possible to use a negative pressure gauge to detect the pressure in the brake booster and determine whether the negative pressure is below a predetermined value in the control circuit 37. Of course.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention, FIG. 2 is a detailed diagram of its control circuit, and FIG. 3 is a flowchart showing an example of a main routine for controlling the engine shown in FIG. 1. FIG. 4 is a flowchart showing an embodiment of engine automatic stop/start processing. 1...Engine, 3...Injector, 5...
Starter, 7...Igniter, 10a, 10b...
... Solenoid, 15 ... Throttle valve, 15
a...Throttle position sensor, 15b...Idle switch, 20...Start switch, 21a
...Neutral range switch, 21b...Parking range switch, 31...Fuel relay,
33...Starter relay, 35...Ignition relay,
37...Control circuit.

Claims (1)

[Scope of utility model registration request] A sensor group that is used in a vehicle that is supplied with engine suction negative pressure and has a brake booster capable of supplying negative pressure with a vacuum pump, and outputs a signal indicating the state of the engine and each part of the vehicle;
stop signal generating means for outputting an engine stop signal when it is determined that an engine automatic stop condition is satisfied based on the signals from the sensor group; and a stop signal generating means that outputs an engine stop signal when it is determined that the engine automatic stop condition is satisfied based on the signal from the sensor group; restart signal generating means for outputting an engine restart signal when it is determined that the engine restart signal is present; engine stopping means for stopping the engine in response to the engine stop signal; and restarting the engine in response to the engine restart signal. In the engine automatic stop/start device, the engine automatic stop/start device has a negative pressure detection means for detecting negative pressure in the brake booster, and the negative pressure detection means detects that the negative pressure in the booster is below a predetermined value. a measuring means for measuring a predetermined time after the detection; and outputting a vacuum pump drive signal for driving the vacuum pump when the negative pressure detecting means detects that the negative pressure in the booster is below a predetermined value. and pump drive signal generating means configured to stop outputting the vacuum pump drive signal when a predetermined time is measured by the measuring means.