Engine fuel supply control strategy

Abstract

In at least some implementations, a method of controlling a fuel-to-air ratio of a fuel and air mixture supplied to an engine, includes the steps of determining an engine deceleration event, determining the number of engine revolutions required for the engine speed to decrease from one speed threshold to another speed threshold, comparing the number of engine revolutions determined above against a revolution threshold, and making the fuel and air mixture richer if the number of engine revolutions determined above is greater than the revolution threshold. The method may also include determining if, before the engine stabilized at a stable engine speed (which may be an engine idle speed), the engine speed decreased below the stable engine speed as the engine decelerated to the stable engine speed from a speed above the stable engine speed, and making the fuel and air mixture leaner if the determination is affirmative.

Dependencies are inferred from the claim text.