Fuel Pressure Regulator: Description and Operation

- The pressure regulator is divided into the fuel chamber and the spring chamber by the diaphragm as illustrated. Fuel is fed to the fuel chamber through the fuel inlet connected with the injector. A difference in pressure between the fuel chamber and the spring chamber connected with the intake manifold causes the diaphragm to be pushed down, and fuel is fed back to the fuel tank through the return line.
- By returning fuel so as to balance the above pressure difference and the spring force, the fuel pressure is kept at a constant level 299.1 kPa (3.05 kg/sq.cm, 43.4 psi) against the intake manifold pressure.