Engine management system - EDC (Fuel system): Description and operation

FUEL SYSTEM

Fuel is drawn from the tank, via a filter which removes particle contamination from the fuel, by a fuel lift pump attached to the side of the cylinder block and driven directly off the camshaft. The fuel pump supplies fuel under constant pressure to the injection pump.

The injection pump meters a precisely timed, exact quantity of fuel to the injectors in response to throttle

variations, injection timing varying with engine speed. Any excess fuel delivered to the injection pump is not injected, but passed back to the tank via the fuel return line.

Fuel is injected in a finely atomised form into a pre-combustion chamber in the cylinder head where it ignites. The burning fuel expands rapidly into the main combustion chamber, creating extreme turbulence which mixes the burning fuel thoroughly with the compressed air, providing complete combustion.

Fuel injection pump

1. Fuel quantity servo potentiometer
2. Fuel quantity servo control unit
3. Fuel shut off solenoid
4. Injection timing device solenoid valve
5. Control spool
6. Injection timing device
7. Injection pump drive shaft
8. Fuel temperature sensor