Fuel Pressure Regulator valve

A  fuel pressure regulator is a solenoid valve.
 FP Regulators are fitted to high pressure
 pumps and or  to the common fuel rail
 in modern common rail diesel cars.

• The function of the FPR is to keep the pressure in the rail at a constant level
• Probably  the most common make is Bosch.
• A  fuel  pressure sensor signals the pressure in the fuel rail to the ECU – the ECU in turn signals the regulator to open or close.
• “The rail contains a pressurised supply of diesel fuel ready for the injectors to use; when the pressure in the rail drops the sensor signals this to the ECU and pressure (via the pump) is restored.”
• The ECU  controls the  supply of  fuel  to the rail from the high pressure pump;
• it does this by means of the Fuel pressure control valve.
• If pressure is getting too high the regulator opens to allow fuel to return to the tank (and pressure drops) It works the opposite way when pressure falls.

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•        Fuel Pressure Regulator valve