Fuel Injector: Description and Operation

Figure 3-6: Fuel Injector Components:

Fuel Injectors
An identical fuel injector nozzle is used for each cylinder. The nozzle is threaded into the cylinder head and positioned so the injector nozzle extends into the combustion prechamber.

The injectors are a spring loaded, valve and pintle design (Figure 3-6). The pintle forms the injector nozzle and the valve seats in the nozzle tip opening.

Fuel is supplied to each nozzle and in the necessary sequence, by the fuel injection pump. The high pressure fuel pulse overcomes spring pressure lifting the valve off its seat. Pressurized fuel then enters the prechamber through the nozzle in the form of a highly atomized spray.

A small amount of fuel travels around the nozzle and valve for lubrication purposes. This fuel cycles back to the fuel return system through the fuel return ports at the upper end of each nozzle.

The fuel injection nozzles are not repairable and are serviced only as an assembly. However, they may be cleaned to remove contamination.