Unit_pump
Unit pump
Modular high-pressure diesel injection system used in commercial vehicle diesel engines
The Unit Pump system[1] is a modular high-pressure diesel injection system, which is closely related to the unit Injector system, and is designed for use in commercial vehicle diesel engines.[2]
The systems use an individual injection pump mounted on the engine block for each cylinder so it is primarily designed for OHV or "cam in the block" engines.[3] The fuel pumps can be either driven by an extra camshaft lobe or by an electrical supply where each pump unit is connected to the injector via a short precise length high-pressure fuel line as opposed to unit Injector systems which combines both a pump and an injector element in a compact unit.
Both systems feature electronically controlled fuel solenoids for precise timing and the injection of fuel quantity is variably adjusted for each cylinder.