Diesel Engine Fuel Cut-off Solenoid


The fuel cut-off solenoid valve opens and closes the fuel passage leading to the suction port. (The valve remains open while the ignition switch is on.)
1. Fuel cut-off solenoid on
The battery voltage is applied to the solenoid and the valve compresses the spring to be drawn upward. As a result, the suction port is opened and the fuel is supplied.
2. Fuel cut-off solenoid off
The current,which flows into the solenoid,is cut off, allowing the valve to retract downward by the spring. As the valve closes the suction port, the fuel supply to the cylinder will stop, causing the engine to stop.
Diesel Engine Anti-reverse Rotation
The diesel engine generally rotates in reverse. If the fuel is injected where the air is drawn from the exhaust side and compressed, the engine will rotate. However, the pump is designed to make reverse rotation for the engine impossible. If the pump rotates in reverse, the fuel will be returned back to the pump housing as the pump plunger moves upward and the suction port is opened. Also, the fuel is not compressed because the pump plunger moves downward, when the delivery port is opened. Therefore the fuel is not injected, making it impossible that the engine to rotate in reverse.

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