General Motors developed an “in-between” technique
called central port fuel injection called CPFI. It uses
tubes from a central injector to spray fuel at each
intake port rather than the central throttle body.
IJAERS/Vol.II/ Issue III/April-June., 2013/57-59
However fuel is continuously injected to all ports
simultaneously, which is less than optimal.
This system is very similar to the standard multi-port
injection system. The main difference lies in the
location and construction of the fuel injector(s).
instead of an injector positioned at each intake
manifold port, the injector(s) are centrally located in
the intake manifold plenum assembly. Hence the
name is given as a” central port fuel injection”