Air/Fuel Ratio Control System

Air/Fuel Ratio Control System consists of 2 injectors, ECU, fuel pressure regulator and various sensors. Air/fuel ratio control is achieved by controlling driving time of the 2 injectors installed on injection mixer. There are 2 types of injectors: small flow and large flow. Amount of fuel injection is basically determined by airflow sensor output frequency corresponding to amount of intake air. When intake air flow is small (frequency decreases), small flow injector is driven. When intake air flow is large (frequency increases), both small and large flow injectors are driven. If airflow sensor malfunctions, backup control drives injectors by engine speed sensor signal.