Fuel Systems: EFI Engine Management: EFI operation

Modes of EFI	A mode of injection describes the timing and sequence of injecting fuel.
Electronic fuel injection	EFI is now the most common fuel system, the injectors spray fuel into the air/intake ports for combustion inside the engine.
Idle speed control systems	Idle speed control systems maintain a suitable idle speed to prevent stalling, when additional loads are placed on the engine.
Feedback & looping	Feedback from the exhaust gas oxygen sensor is used to maintain closed loop control of the air-fuel mixture.
Cold start systems	Cold start systems provide additional fuel during starting conditions, according to engine temperature.
Air measurement	The vane-type airflow sensor measures the quantity of air flowing into the engine by deflecting a spring-loaded vane across a potentiometer. This provides a signal voltage to the ECU.
Air-flow monitoring	Depending on the application, different kinds of sensors measure different properties of the air entering the engine, including its temperature, volume, density, and mass.
Variable intake manifold system	Variable intake manifold systems vary the effective manifold pipe length, to extend the torque curve over a wider RPM range.
Electrical functions	The ECU continuously receives information from sensors in the form of electrical signals, to determine injector pulse width.
EFI wiring diagram	Identification of the sensors and their inputs allows easier identification of the wiring diagram for any given system.

Topic	Summary