Deceleration Fuel Cut-Out

To reduce fuel consumption, the deceleration fuel cut-out is activated when the throttle valve is closed and the engine speed is above approximately 1000-1200 RPM. The engine control module continues to cutout the injection and retard the ignition timing until the engine speed has dropped below the 1000-1200 RPM cut-in speed. At and below the cut in speed, fuel injection resumes and the ignition timing is advanced once again. The cut-in speed is dependent upon the engine temperature and the rate of deceleration. Fuel economy indicator provides a visual demonstration of this function. In the case of a sudden change in the throttle position towards the full load direction, the engine control module increases the quantity of injected fuel (ms time increased) for the duration of the request for acceleration and also advances the ignition timing. The engine control module provides the acceleration enrichment while also taking into account the criteria for maximum torque, emissions, detonation and knock sensor input. See Fig 1.