JPS59126062A - Injection timing control device for unit injector - Google Patents

Abstract

PURPOSE:To control the injection timing and the injecting amount of the unit injector simply and surely by an electric means by a method wherein the timing of closing a metering port is varied by a pressure-feeding plunger in the unit injector. CONSTITUTION:The unit injector 1 is equipped wth the sending plunger 3, connected to a follower 2, while the pressure-feeding plunger 3 sends fuel in a fuel reservoir 4 forcibly to drive an injection plunger 5. The injection plunger 5 injects the fuel in a pump chamber 6 into a combustion chamber 9 from the injecting port 8 of a nozzle 7. Teeth 20 are cut around the outer periphery of said sending plunger 3 and a rack 21 is engaged therewith. The rack 21 is driven by a servomotor 22 driven and controlled by a controller 19. According to this method, the rack 21 is driven by the servomotor 22 to pivot the plunger 3 when it is necessary and a timing to close the metering port 24 by the cut part 23 of the plunger 23 may be varied.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device in which injection timing is variable in a unit injector.

The unit injector has no injection tube, so it has good response, and there are no problems with metering the injection amount or pulsation.
These days, there is a strong demand for low fuel consumption, and they are attracting attention.

However, one of the drawbacks of unit injectors is that the fuel injection timing cannot be controlled.

That is, since a unit injector is attached to each cylinder and driven by a cam or the like, it is impossible to change the injection timing with a simple mechanism as in conventional injection pumps.

The present invention focuses on the relationship between the pressure-feeding plunger and the metering port of the unit injector, and provides a unit injector in which the fuel injection timing is substantially variable by changing the timing at which the pressure-feeding plunger closes the metering port. This is what I am trying to do.

The present invention will be explained below with reference to the drawings.

The unit injector 1 has a pressure-feeding plunger 3 connected to a follower 2, and the pressure-feeding plunger 3 forces fuel in a fuel reservoir 4 to drive an injection plunger 5. The injection plunger 5 injects the fuel in the pump chamber 6 into the combustion chamber 9 from the injection port 8 at the end of the nozzle 7 . The solenoid valve 10 provides the amount of fuel to be injected into the pump chamber 6 each time, and metering is determined by the opening time of the solenoid valve 10.

The fuel in the fuel tank 11 is fed to the feed pump 1 on the one hand.
2, the fuel is supplied to the electromagnetic valve 10 via a filter 13 and a surge tank 14, and on the other hand, it is supplied via a feed pump 15 to a filter 16 and a surge tank 17 to the pumped fuel reservoir 4.

A controller 19 is provided which receives and calculates the signals of the trigger system 18 and opens and closes the solenoid valve 10.

The above configuration is a known configuration.
(See No. 262) The present invention adds the following configuration.

Cut teeth on the outer periphery of the pressure-feeding plunger 3, and attach the rack 2 to this.
1 is engaged. The pressure-feeding plunger 3 is pressed 21t;t
The servo motor 22 is driven by a controller 19, and the servo motor 22 is driven and controlled by the controller 19.

A diagonally cut portion is provided at the lower end of the pressure-feeding plunger 3, and the closing timing of the metering port is changed by the cut portion.

To explain the present invention in detail, when the follower 2 is driven by a cam or the like (not shown), the pressure-feeding plunger 3 descends. Then, the metering boat is closed, and from this point on, the fuel in the fuel reservoir 4 is pumped to drive the injection plunger 5. Therefore, the fuel in the pump chamber 6 is injected into the combustion chamber 9 from the injection port 8 at the end of the nozzle 7.

When the fuel injection is completed, the operating state detected by the trigger system 18 is calculated by the controller 719, the next injection amount is determined by the opening time of the electromagnetic valve 1o, and the fuel is injected into the pump chamber 6.

Now, if the operating state detected by the trigger system 18 is determined by the calculation of the controller 19 to require a change in the injection timing, the servo motor n drives the rack 21. Then, the pressure-feeding plunger 3 rotates, changing the timing at which the cut portion closes the metering boat.

In the above description, since there are various specific structures of the unit injector, the present invention is not limited to these structures.

In addition, the trigger system is adopted depending on engine speed, load lever position, transmission gear, cooling water temperature, etc.

Furthermore, any mechanical, electrical, or fluid mechanism may be used as the servo motor for driving the rack.

Through the above, the present invention provides the following effects.

The injection timing and injection amount of the unit injector can be reliably controlled by electrical means.

This can be achieved without making any special changes to conventional equipment.

[Brief explanation of the drawing]

The figure is a schematic cross-sectional view showing one embodiment of the present invention. 1: Unit injector, 3: Pressure feeding plunger, 4:
Fuel reservoir, 5: Injection plunger, 6: Pump chamber, 23:
Cut part, 24: Metering port agent Patent attorney 3 parts

Claims (1)

[Claims] In a unit injector having at least a pressure-feeding plunger and injecting fuel from a nozzle end injection port into a combustion chamber by operating the pressure-feeding plunger, the pressure-feeding plunger is rotatably provided, and the end of the pressure-feeding plunger is cut diagonally. ,
A pressure-feeding plunger rotation mechanism is provided to control when the pressure-feeding plunger closes the metering port of the fuel reservoir, and a solenoid valve is provided to send injected fuel to the unit injector every - times of fuel injection, thereby controlling the engine operating status. An injection timing control device for a unit injector, characterized in that the rotation mechanism and the electromagnetic valve are controlled by a controller 2 that detects and issues a signal.