| Topic | Summary |
| Diesel tanks & lines |
The fuel tank stores fuel away from the engine. Baffles ensure the pickup tube is always submerged in fuel. This stops air entering the system. |
| Diesel fuel filters |
Fuel filters remove abrasive particles and water. |
| Lift pump |
A diaphragm-type lift pump can be mounted on the engine, or the injection pump. An eccentric on a camshaft pushes on a rocker arm. It acts on a diaphragm to create a pressure difference, which lifts fuel from the tank to the injection system. |
| Plunger pump |
A plunger-type lift pump is mounted on the in-line injection pump, and driven by a cam inside the in-line injection pump housing. |
| Priming pump |
Light vehicle diesel engines use a priming pump to remove air from the fuel system. Otherwise, the engine would have to be cranked over with the starter motor, to bleed and prime the system. |
| Inline injection pump |
An in-line injection pump meters the fuel and raises its pressure. The basic principle is for a plunger to act on a column of fuel, to lift an injector needle off its seat. |
| Mechanical or pneumatic governors |
A mechanical governor uses rotating fly weights to control movement of a rack against a spring. A pneumatic governor has a venturi unit, linked to a diaphragm assembly, on the in-line injection pump housing. |
| Distributor-type injection pump |
The distributor-type pump uses a vane-type transfer pump to fill the single pumping element. This then raises fuel pressure to injection pressure. A distribution system then distributes fuel to each cylinder, in the firing order of the engine. |
| Diesel injectors |
The injection pump delivers fuel to the injector. As fuel pressure rises, it acts on the needle valve, eventually lifting it from its seat. Highly-pressurised fuel enters the engine in an atomised spray at a high velocity. |
| Glow plugs |
Glow plugs pre-heat the incoming air so that ignition can more easily occur. This assists a cold engine to start more reliably, and once the engine is running, the glow plugs are no longer required. |
| Cummins & Detroit Diesel injection | Unit injectors have been available for many years in heavy commercial diesel engines. These include the 'Cummins Pressure Time System' and the 'Detroit Diesel System'. For both systems actuation is a result of an extra lobe on the engine camshaft for each cylinder. |
