Used for BOSCH common rail system to control the press of the high press pump.
The regulating valves for the pressure is fixed on the body of the high pressure pump or Rail and has the function to regulate and maintain the pressure in the Rail according to the loading condition of the engine. In case the pressure is too high, the valve will open in order to make part of the fuel flow from the Rail to the tank; In case of too much low pressure in the Rail, the valve will close itself separating in this way the high pressure side from the low pressure one.