Fuel Pressure Regulator: Description and Operation

Fuel Pressure Regulator:

DESCRIPTION
The fuel pressure regulator is diaphragm-operated relief valve consisting of diaphragm, spring and valve. It keeps the fuel pressure applied to the fuel injector 180 kPa (26 psi) higher than that in the intake manifold at all times.

OPERATION
The pressure applied to the chamber "A" of fuel pressure regulator, shown in the accompanying image, is intake manifold pressure and that to the chamber "B" is fuel pressure. When the fuel pressure rises more than 180 kPa (26 psi) higher than the intake manifold pressure, the fuel pushes the valve in the regulator open and excess fuel returns to the fuel tank via the return pipe.