Fuel Injector: Description and Operation

Injection Illustration:

PURPOSE
The fuel injectors supply highly atomized fuel at the intake port to ensure optimum combustion efficiency.

Injection Spray Pattern:

OPERATION
The injection valve consists of a valve body and needle valve with fitted solenoid armature. The valve body contains the solenoid winding and the guide for the needle valve. When there is no current in the solenoid winding the needle valve is pressed against its seat on the valve outlet by a helical spring. When a magnetic field is generated in the solenoid winding the needle valve is lifted by approx. 0.1 mm and the fuel can flow out through calibrated annular orifices.

The injection valves receive power from the Digital Motor Electronic (DME) main relay and are operated by ground pulses from the DME control unit. The duration of injection is determined from various inputs to the DME control unit.

The front end of the needle valve is provided with a specially ground pintle and two openings for atomizing and directing the fuel at the intake valves. The open time of the valve lies in the range of 1 to 1.5 ms.