establish the timing sequence. The engine is fitted with
a variety of sensors and switches to gather the following
Intake air temperature
Engine coolant temperature
Throttle valve position
Intake manifold airflow
The computer receives this information and uses it to
calculate the amount of fuel delivered at each injection
cycle. The computer is capable of changing the rate of
fuel delivery to the engine hundreds of times a second,
making the system extremely accurate. The computer
regulates the amount of fuel delivered by varying the
duration of injector operation.
CONTINUOUS FUEL INJECTION SYSTEMS
Continuous fuel injection systems (fig. 5-3) provide
a continuous spray of fuel from each injector at a point
before the intake valve. Because the entrance of the fuel
into the cylinder is controlled by the intake valve, the
continuous system will fulfill the requirements of a
gasoline engine. Timed injection systems, though a
necessity on diesel engines, cost more than continuous
systems. They are used on gasoline engines only when
more precise fuel metering is desired.
Figure 5-3.-Continuous injection.