Combined warm-up enrichment, engine roughness and exhaust gas sensor control for EFI engine

摘要

In an electronic fuel injection system for an internal combustion engine an oxygen sensor tests the exhaust gas for oxygen content and provides a feedback signal for fuel/air mixture control. During cold start and engine warm-up the oxygen sensor is inoperative and mixture is controlled as a function of engine coolant temperature. During this phase the mixture may be excessively lean causing rough engine running. Means responsive to cylinder misfirings temporarily enrich the mixture to eliminate engine roughness.