The diaphragm-type fuel pressure regulator is designed to maintain a constant pressure of the injected fuel, depending on the vacuum in the intake manifold. It consists of a metal body (1) (pic. 3.24), aperture (2), springs (3), branch pipe (4) vacuum supply from the inlet pipeline. branch pipe (5) fuel supply, drain pipe (6) and valve (7).
If the fuel pressure in the chamber «A» increase the force of the spring (3), then the valve (7) opens and excess fuel drains into the tank. Camera «b» connected by a hose to the inlet pipeline, depending on the degree of vacuum in which the spring (3) act on the valve (7) so that the pressure difference between the chambers «A» and intake piping has always been constant. As a result, regardless of the load on the engine, the pressure supplied to the injectors remains constant.