Engine control algorithm-cold start A/F modifier

Abstract

A method and apparatus for controlling the amount of fuel used in combustion during open-loop run mode of a internal combustion engine. A lookup table calibrated to a fuel with a low driveability index is used to make a fueling decision for open-loop run mode. Then, at least one of the following indicators of fuel problems is monitored: the engine misfire detection system, the engine speed and the manifold absolute pressure. If any of these indicators detect a problem with the amount of fuel the engine is receiving, a fuel increase is calculated and implemented in one or more steps. A problem is indicated if an engine misfire is detected, the engine speed drops below a predetermined threshold value, or the manifold absolute pressure rises above a predetermined threshold value. The fuel increase is limited by a calculation based upon a fuel with a high driveability index.

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