Indirect injection - Definition

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.