Fuel pressure regulator

The positive for the injector supply is supplied via the current limiter resistor (1), by the pump relay terminal; the circuit closes to earth in the control unit (2) via terminal 25.

The use of the resistor (1) makes it possible to prevent the injector, which contains a small copper coil inside, from overheating. The resistance of the current limiter is 2.85-3.15 ohm at 23°C.

FUEL PRESSURE REGULATOR

The regulator (1), which is the mechanical diaphragm type, is fitted on the injector holder turret (2).

The function of the pressure regulator is to keep the pressure at which the fuel is sent to the injector constant at around 1 bar.

The fuel under pressure coming from the electric pump reaches the hydraulic chamber (3) in the pressure regulator.

If the pressure at the diaphragm (4) exceeds the value of 1 bar, it overcomes the loading of the opposing spring (5) and moves the plate (6) allowing the fuel to flow through the duct (7) into the tank.

In the upper chamber (8) of the regulator there is a port (9) which places the chamber (8) in contact with the outside so that a vacuum is not produced in the actual chamber.