Direct injection (DI) is a type of fuel injection system where fuel is injected directly into the combustion chamber. The alternative is to inject into the intake manifold or a pre-mixing chamber, a process known as indirect injection.
Early fuel injection systems used direct injection, though indirect injection then took over because it provided more complete mixing of the fuel and air and this aided combustion.
In recent years improved injection technology and the advent of electronic control systems have led to a resurgence of interest in direct injection, which offers benefits to efficiency, emissions and fuel consumption.
