It is oiltight, and during operation all moving parts are lubricated by fuel oil under pressure, so that no additional lubrication system is required. Fuel injection is effected by a single element having twin opposed plungers located within a transverse bore in a central rotation member which acts as a distributor. The pump plungers are actuated by lobe on an internal camring. Fuel is accurately metered to the pumping element, and the high pressure charges are distributed to the engine cylinders at the required timing intervals through ports in the rotor and the hydraulic head. The integral governor is of the mechanical fly-weight type, and gives accurate control of engine speed under all load conditions.
Most pumps have an automatic device which varies the point of commencement of injection.
The single pumping element ensures uniform delivery of fuel to each engine cylinder, and eliminates having to balance the deliveries from each of the high-pressure delivery pipes. As emission legislation is tightened in response to environmental pressures, the demand for cleaner more economical engines intensifies. The new generation of diesel engines need to have better fuel consumption, lower noise and exhaust emissions than current models. This has created a demand for fuel injection equipment which optimises engine performance and minimises emissions through the use of high injection pressures and electronic control of injection timing and fuelling.