Fuel Pressure Regulators

An essential part of the Fuel System, the Fuel Pressure Regulators' sole purpose is to maintain fuel pressure at a constant differential to manifold vacuum under all engine load conditions. The fuel pressure regulator is responsible for controlling the set fuel pressure of the system.

On returnless fuel systems (RLFS), the pressure regulator is part of the in tank unit installed in the fuel tank. The fuel rail pressure is maintained at a constant level with reference to the surrounding pressure. This means that the difference between the fuel rail pressure and manifold pressure is not constant and must be taken into account when the injection duration is calculated.

The fuel pressure regulator (Fig.1) is of the diaphragm controlled overflow type. A rubber fabric diaphragm (4) divides the pressure regulator into a fuel chamber and a spring chamber. Through a valve holder (3) intergrated in the diaphragm, the spring (2) forces a moveable valve plate against the valve seat so that the valve closes. As soon as the pressure applied to the diaphragm by the fuel exceeds the spring force, the valve opens again and permits just enough fuel to flow back to the fuel tank that equilibrium of forces is achieved again at the diaphragm.

Bosch fuel pressure regulators are competitively priced and sold through leading automotive part stockists. Please see our ‘Dealer Locator’ at the top of the page to locate you local store.