Fuel Injector: Description and Operation

FUEL INJECTOR
The fuel injectors are solenoid operated valves. When a fuel injector solenoid is energized (pulsed) the injector needle valve moves, allowing pressurized fuel to pass through the injector and mix with air entering the engine. The Engine Control Module (ECM) controls injector timing and pulse width . The ECM pulses the fuel injectors based on information provided by its network of engine sensors. The ECM uses the crankshaft position sensor to determine when to pulse the injectors. Engine coolant temperature, intake air temperature, air flow, and throttle p0sition data are all used by the ECM to calculate injector pulse width.

The ECM also uses its network of sensors to determine whether all injectors should be pulsed at the same time (simultaneous injection) or each injector should be pulsed individually (sequential injection). Sequential injection is almost always used during normal engine operation, simultaneous injection may be used when the engine is being cranked.

The injectors inject fuel according to a signal coming from the ECM. The volume of fuel injected by the injector is determined by the time the solenoid valve is energized.