Diesel fuel injection parts

The performance of diesel engines is heavily influenced by their injection system design. In fact, the most notable advances achieved in diesel engines resulted directly from superior fuel injection system designs.

While the main purpose of the system is to deliver fuel to the cylinders of a diesel engine, it is how that fuel is delivered that makes the difference in engine performance, emissions, and noise characteristics.

Start of injection (SOI) or injection timing is the time at which injection of fuel into the combustion chamber begins.

It is usually expressed in crank angle degrees (CAD) relative to TDC of the compression stroke. In some cases, it is important to differentiate between the indicated SOI and actual SOI.

SOI is often indicated by an easily measured parameter such as the time that an electronic trigger is sent to the injector or a signal from a needle lift sensor that indicates when the injector needle valve starts to open.