Injector

INJECTOR

The injectors are fitted to the inlet ducts immediately before the inlet valve.

The injector nozzle is positioned so that the fuel jet strikes the intake valve directly.

The injectors are held in place by the fuel manifold, which presses the injectors into their seats in the inlet ducts. They are also anchored to the fuel manifold by safety clips. Two rubber rings seal the inlet duct and fuel manifold.

Longitudinal section through electromagnetic injector

1. Filter
2. Supply connector
3. Magnetic winding
4. Magnetic core
5. Needle nozzle
6. Spray pin
7. Abutment plate

The injectors are responsible for metering the amount of fuel necessary to the engine. These devices may take up only two stable conditions - either open or closed. They consist of a nozzle controlled by a solenoid and return spring. In rest position needle (6), which is integral with core (4) is pushed by the spring against the injector tip in order to close the hole and ensure a seal to prevent fuel emerging.

As soon as the winding is excited, core (4) is attracted, the spring is compressed to open the nozzle hole and permit fuel to emerge. Assuming fuel physical properties (viscosity and density) and the pressure gap (pressure regulator) to be constant, the amount of fuel depends only on injector opening time (Tj). The injector needle is non-oxidizable and thus unaffected by any impurities (water, methanol, ethanol, etc.) in commercial fuels.