CONTINUOUS FUEL INJECTION SYSTEM
fuel injection systems (fig. 4-45) provide a
continuous spray of fuel from each injector at a point in the intake port located just
before the intake valve. Because the entrance of the fuel into the cylinder is controlled
by the intake valve, the continuous system fulfills the requirements of a gasoline engine.
operation of a continuous fuel injection is as follows:
is fed to the system by an electric fuel pump that delivers fuel to the mixture control
unit. A fuel pressure regulator maintains fuel line pressure and sends excess fuel back to
mixture control unit regulates the amount of fuel that is sent to the injectors based on
the amount of air flow through the intake and the engine temperature. The unit is operated
by the air flow sensing plate and warm-up regulator.
accelerator pedal regulates the rate of air flow through the intake by opening and closing
the throttle valve.
cold-start injector is installed in the intake to provide a richer mixture during engine
start-up and warm-up. It is actuated by electric current from the thermal sensor any time
the temperature of the coolant is below a certain level.
for a continuous fuel injection system is a simple spring-loaded valve. It injects fuel
all the time the engine is running. A spring holds the valve in a normally closed position
with the engine OFF. This action keeps fuel from dripping into the engine. When the engine
STARTS, fuel pressure builds and pushes the injector valve open. A steady stream of
gasoline then sprays toward each intake valve. The fuel is pulled into the engine when the
intake valves open.