Indirect injection

Encyclopedia : I : IN : IND : Indirect injection

In an internal combustion engine, the term indirect injection refers to a fuel injection method which does not inject fuel directly into the combustion chamber. Gasoline engines are usually equipped with indirect injection systems, where a fuel injector delivers fuel at some point before the intake valve.

An indirect injection diesel engine delivers fuel into a chamber off the combustion chamber, called a prechamber, where combustion begins and then spreads into the main combustion chamber. The prechamber is carefully designed to ensure adequate mixing of the atomized fuel with the compression-heated air. This has the effect of slowing the rate of combustion, which tends to reduce audible noise. It also softens the shock of combustion and produces lower stresses on the engine components. The addition of a prechamber, however, increases heat loss to the cooling system and thereby lowers engine efficiency.

Aside from the above advantages, early diesels often employed indirect injection in order to use simple, flat-top pistons, and made the positioning of the early, bulky diesel injectors easier.

From Wikipedia, the Free Encyclopedia. Original article here. Support Wikipedia by contributing or donating.
All text is available under the terms of the GNU Free Documentation License See Wikipedia Copyrights for details.