Fuel Pressure Control Solenoid: Description and Operation
DESCRIPTIONFuel Pressure Solenoid:
The fuel pressure solenoid is attached to the rear of the fuel rail. A sealing metal disc seals the valve to the rail. The seal is not serviceable and looses it's sealing properties upon removal of the solenoid. Therefore, the solenoid must be replaced when ever it is removed from the rail. The solenoid controls and maintains the rail pressure constant along with a control current transmitted by the engine control module (ECM).
OPERATION
Fuel Pressure Solenoid Operation:
High pressure which is present in the fuel rail flows to the ball seat of the pressure solenoid. The specified pressure required by the system is built up in the rail by the fuel pressure solenoid building up a magnetic force which corresponds to this specific pressure by means of a control current from the electronic control module (ECM). This magnetic force equals a certain outlet cross section at the ball seat of the valve. The rail pressure is altered as a result of the quantity of fuel which flows off. The current fuel pressure is signaled by the fuel rail pressure sensor to the engine control module (ECM). The controlled fuel flows back along the return fuel line, into the tank.
In a deenergized state, the fuel pressure solenoid is closed as the spring force presses the ball into the ball seat. When driving, the fuel pressure solenoid is constantly open. When engine is started, the fuel pressure solenoid is held closed by magnetic force. When driving, the pressure of the fluid counteracts the magnetic force of the coil and the slight spring force.