JPH0144737Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a device for cooling a fuel injector provided in an engine.

[Description of Prior Art] A fuel injector injects and supplies fuel to an engine according to a valve opening time signal from a fuel injection control device, and is disposed in each cylinder of the engine. Therefore, it is easily affected by the heat of the engine, and in particular, when the engine is stopped after running for a long time when the outside temperature is high, the cooling by the radiator fan is stopped, the temperature of the injector rises, and the fuel inside the injector increases. There is an extremely high possibility that so-called vapor lock, which will form into bubbles, will occur. When vapor lock occurs, fuel is not injected from the injector when the engine is restarted for some reason, and there is a problem in that the engine cannot be started until the injector is naturally cooled.

In order to improve these problems, the present applicant has provided a blower to cool the injector, and when the engine is stopped, the time determined according to the temperature of the cooling water and the temperature of the outside air at that time. We proposed a configuration in which the blower is driven only in sections to cool the injector (Utility Application No. 35423/1983). According to this, since the injector is cooled by the blower even after the engine is stopped, it is possible to prevent vapor lock from occurring. However, since the blower is driven while the engine is stopped, depending on the state of charge of the battery, the battery may rise and the starter motor may become unable to be driven.

[Purpose of the invention] The invention was made based on the above viewpoints,
The purpose is to provide a cooling device that can cool a fuel injector without causing battery build-up.

[Means for Achieving the Object] In the present invention, in a cooling device for a fuel injector provided in an engine equipped with a fuel injector that injects and supplies fuel, a blower that provides cooling air to the fuel injector is provided. and 3 connected in series to the energizing circuit of this blower.
The first switching means is configured to close when the temperature near the fuel injector reaches a predetermined temperature or higher and to open when the temperature in the vicinity of the fuel injector reaches a predetermined temperature, and the second switching means , a cooling device configured to close when the ignition switch is off and open when the ignition switch is turned on; Through this, the above objectives will be achieved.

[Embodiment of the invention] FIGS. 1 and 2 are configuration diagrams showing an embodiment of the invention.

A fuel injector 1 is installed in each cylinder of the engine 2, and each injector 1 is supplied with fuel under pressure from a fuel pump via piping (not shown), and also receives valve opening control calculated by a control unit. A time signal is now provided. 3 is a radiator fan, and 4 is a blower. The blower 4 is arranged in the engine room 5 to provide cooling air to the injector 1. A temperature switch 6 is attached to the engine 2 in this example so that the temperature of the injector farthest from the blower 4 can be detected. The temperature switch 6 is made of bimetal, for example, and the injector 1
The device is configured to close at a temperature above a predetermined temperature, including the temperature at which a vapor lock occurs, and to open at a temperature below that temperature.

The temperature switch 6, as shown in FIG.
One end of the switch terminal is connected to a battery (not shown), and the other end is connected to one end of the normally closed contact 7a of the relay 7. The other end of the normally closed contact 7a of the relay 7 is connected to one end of the normally open contact 8a of another relay 8, and the other end of this normally open contact 8a is connected to one current-carrying end of the fan motor 9 of the blower 4. There is. The other current-carrying end of the fan motor 9 is grounded. The excitation coil 7b of the relay 7 is inserted between the battery and ground via an ignition switch 10, and is configured so that when the switch 10 is turned off, the contact 7a is closed, and when it is turned on, the contact 7a is opened. There is. A diode 11 inserted in parallel with the exciting coil 7b is for preventing back electromotive force. One end of the excitation coil 8b of the relay 8 is grounded, and the other end is connected to the relay drive circuit 12. The relay drive circuit 12 excites the relay 8 to open the normally open contact 8 when the battery voltage is higher than a predetermined voltage.
a, and when the voltage is below a predetermined voltage, the relay 8 is deenergized and the normally open contact 8a is opened. The predetermined voltage is set to a voltage at which the starter motor can be driven. Battery voltage is applied to the relay drive circuit 12 via a wiring 13 drawn out between the normally closed contact 7a of the relay 7 and the normally open contact 8a of the relay 8. The relay drive circuit 12 includes a series connection of a resistor 14 and a Zener diode 15 inserted between the wiring 13 and the ground, and resistors 16 and 17 inserted in parallel with this series connection between the wiring 13 and the ground.
, a comparator 18 , and a transistor 19 that is turned on/off by the output of the comparator 18 . The (-) input terminal of the comparator 18 is connected between the resistor 14 and the Zener diode 15 via the input resistor 20, and a constant voltage from the Zener diode 15 is applied as a reference voltage. Comparator 1
The (+) input terminal of 8 is connected between resistors 16 and 17 via an input resistor 21, and a divided battery voltage is applied thereto. The output terminal of comparator 18 is connected to the base of transistor 19 via resistor 22. Such a comparator 18 provides an H level output when the divided battery voltage is higher than the reference voltage, and provides an L level output when it is lower. The collector of the transistor 19 is connected to the wiring 13, and the emitter thereof is connected to the excitation coil 8b of the relay 8. Note that a resistor 23 inserted between the transistor 19 and the ground is an input resistance of the transistor 19, and a diode 24 inserted in parallel with the excitation coil 8b of the relay 8 is a diode for preventing back electromotive force. .

With the above configuration, when the engine 2 is in operation, the normally closed contact 7a of the relay 7 is opened when the ignition switch 10 is turned on. The temperature switch 6 becomes closed when the temperature near the injector 1 rises to a predetermined temperature or higher during operation of the engine 2. While the engine 2 is running, the normally closed contact 7a is open, so even if the temperature switch 6 is closed, battery voltage is not supplied to the relay drive circuit 12 and the relay 8
The normally open contact 8a is placed in an open state. While the engine 2 is running, the normally closed contact 7a and the normally open contact 8
When opening a, the energizing circuit of the fan motor 9 of the blower 4 is cut off, and the injector 1 is cooled by the radiator fan 3 accompanying the operation of the engine 2.

When the operation of the engine 2 is stopped by turning off the ignition switch 10, the normally closed contact 7a of the relay 7 is closed, and battery voltage is supplied to the relay drive circuit 12 through the closed temperature switch 6. be done. As a result, the Zener diode 15
The reference voltage according to the above equation and the battery voltage divided by the resistors 16 and 17 are input to the comparator 8. If the battery voltage is equal to or higher than a predetermined voltage, the output of the comparator 18 becomes H level, the transistor 19 becomes conductive, and the normally open contact 8a of the relay 8 is closed. As a result, a battery voltage is applied to the fan motor 9, and the injector 1 is cooled. The drive of the fan motor 9 is stopped when the temperature near the injector 1 falls below a predetermined temperature or when the battery voltage drops below a predetermined voltage. That is, when the temperature near the injector 1 falls below a predetermined temperature, the temperature switch 6 opens, and when the battery voltage falls below a predetermined voltage, the battery voltage divided by the resistors 16 and 17 opens. The voltage becomes lower than the reference voltage, the output of the comparator 18 changes to L level, the transistor 19 turns off, and the normally open contact 8a of the relay 8
This is for the sake of development.

[Effect of the invention] As explained above, according to the invention, after the engine is stopped by turning off the ignition switch,
When the temperature near the injector is above the predetermined temperature and the battery voltage is above the predetermined voltage, the blower is driven, and the temperature near the injector drops below the above predetermined temperature, or the battery voltage drops below the above predetermined voltage. Since the blower is configured to stop driving when the engine stops, it is possible to prevent the starter motor from being unable to be driven when the engine is restarted due to the blower being driven after the engine is stopped.
In addition, since the blower is controlled by the temperature near the injector, if the engine temperature is not high, such as when the engine stops immediately after starting, the blower will not be driven or will only be driven for a short time. On the other hand, when the temperature is high, as long as the battery voltage does not drop below a predetermined voltage, the blower is driven until the temperature near the injector drops to a predetermined temperature, thereby allowing efficient cooling.

[Brief explanation of the drawing]

FIGS. 1 and 2 are configuration diagrams showing an embodiment of the present invention. 1... Fuel injector, 2... Engine, 4... Blower, 6... Temperature switch, 7, 8
... Relay, 9 ... Fan motor, 10 ... Ignition switch, 12 ... Relay drive circuit.

Claims (1)

[Scope of utility model registration request] A cooling device for a fuel injector installed in an engine equipped with a fuel injector that injects and supplies fuel includes a blower that provides cooling air to the fuel injector, and three blowers inserted in series in the energizing circuit of the blower. the first switching means is configured to close when the temperature in the vicinity of the fuel injector reaches a predetermined temperature or higher and to open when the temperature in the vicinity of the fuel injector reaches a predetermined temperature, and the second switching means: The ignition switch is configured to close when the ignition switch is off and open when the ignition switch is on, and the third switching means is configured to close when the battery voltage is higher than a predetermined voltage and open when the battery voltage is lower than that. A cooling system for the fuel injector.