An injection pump is part of a mechanical engine’s fuel delivery system. It is what pumps fuel into the cylinders of an engine. Generally, the pump is mechanically driven by the crankshaft by gears or a toothed timing belt.

In a 4-stroke engine, the fuel pump moves at fifty percent (or half) of the crankshaft speed. The pump then delivers a specific, measured amount of fuel through a fuel line, and then through an atomizing nozzle. The timing of the movement is such that fuel is made available, or pumped, slightly before the top of a cylinder’s compression stroke. This timing allows the engine to burn. or combust the fuel, in the combustion chamber of an internal combustion engine.

An analogy to the human body is that an injection pump is the heart of an engine system that delivers, or pumps, the fuel into the engine (stomach) which takes that fuel, and converts it to mechanical power.

Today, the use of mechanical injection pumps is being minimized in order to reach emission standards, and to increase fuel economy. New systems use higher pressure pumping the fuel creating a finer mist resulting in lower emissions and better fuel efficiencies.