Air-fuel ratio control system of internal combustion engine

摘要

An air-fuel ratio control system for an internal combustion engine. Excessive fuel supplying at fuel cut reset time is avoided, by interrupting the fuel supply when a fuel cut control signal is being output. An amount of fuel cut time during which the fuel cut control signal is output is determined, and a hold time is also determined. This hold time corresponds to an amount of time necessary for combustion gas to reach a feedback sensor, and be included in the feedback control signal, after termination of the fuel cut. A feedback or closed loop system is used during normal operations. An open loop control signal is used during fuel cut time, and for a period of time equivalent to the value of the hold time after the end of this fuel cut time. Therefore, open loop control is used until exhaust gases have again reached the feedback sensor so that feedback or closed loop control can thereafter be used.