Fuel pressure regulator

A positive injector supply current is supplied through the fuel pump relay; the circuit is earthed in the control unit via terminal 21.

Fuel pressure regulator

The mechanical diaphragm regulator (1) is fitted in the injector turret (2).

The function of the fuel pressure regulator is to maintain fuel feed pressure to the injector at a level of about 1 bar.

Fuel under pressure from the electric pump reaches hydraulic chamber (3) of the pressure regulator.

If pressure on membrane (4) exceeds a level of 1 bar, it overcomes the load on counter-spring (5), and moves plate (6) to allow fuel to flow out through a channel (7) in the tank.

Hole (9) in the top chamber (8) of the regulator brings chamber 8 into communication with the outside so that a vacuum does not build up inside the chamber.

When the engine stops, fuel feed is also shut off. The pump check valve and injector close. In this way, feed pressure is maintained for a certain period in the hydraulic section.

This form of operation prevents the formation of vapour bubbles as a result of fuel in the system being heated by the engine to ensure trouble-free starting at all times.