Pääruiskutus

Pääruiskutus, often translated as "main injection" or "primary injection," refers to a crucial stage in the operation of internal combustion engines, particularly in diesel engines. This is the initial and most significant delivery of fuel into the combustion chamber. The timing and amount of pääruiskutus are critical for initiating the combustion process, influencing engine performance, fuel efficiency, and emissions.

In a diesel engine, the fuel is injected at very high pressure into the hot, compressed air in the cylinder. The pääruiskutus is designed to be the main charge of fuel that ignites and drives the piston downwards. It's typically followed by secondary injections, or post-injections, which help to control the combustion rate, reduce noise (diesel knock), and manage exhaust gas temperatures and emissions like soot. The precise control of the main injection event, including its start timing and duration, is managed by the engine's fuel injection system, often electronically controlled. Factors like engine load, speed, and temperature all influence the parameters of the pääruiskutus to optimize combustion.