| 摘要 |
PURPOSE:To enable short-time injection when the solenoid valve is used in a hydraulic fuel injection device by forming a clearance for communicating a return port and a tank port with each other when the valve portion of a spool opens a port which is open to the bottom face. CONSTITUTION:A pump port P is connected to an operating oil pump 5, and an actuator port A and a return port R are both connected to respective portions of the pressure receiving room 21 of a hydraulic fuel injection device, and a tank port T to an operating oil tank 6. When the pump port P and the actuator port A are communicated with each other the pressure receiving room 21 fills with operating oil because of the return port R being closed by the valve portion 13c of a spool 13, and thereby a plunger 24 is put in a returning movement against the pressing force of a pressure spring 23. After the plunger 24 is stopped, the pump port P and the actuator port A are disconnected from each other by switching of the solenoid valve 1, and the return port R is opened, whereby operating oil contained in the pressure receiving room 21 is allowed to flow into the solenoid valve 1 from the return port R to pass through a clearance 14 formed between the spool 13 and a spool hole 12 and is discharged from the tank port T to the operating oil tank 6. |
