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-pressurized fuel enters the engine in an atomized spray at a high velocity.
|
Glow plugs
|
In the tip of the glow plug is a coil of a resistive wire or a filament which heats up when electricity is connected.
|
| 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. |
