Fuel cut-off and fuel-supply recovery control system for internal combustion engine coupled to an automatic power transmission with a lock- up torque converter

摘要

A fuel cut-off and fuel-supply recovery control system for an internal combustion engine coupled to an automatic power transmission with a lock- up torque converter having a lock-up device operable at either one of an open converter state and a locked-up state through a lock-up control based on engine and vehicle operating conditions, comprises an electronic control module configured to store a fuel-cut engine speed (N.sub.1, N. sub.3) above which a fuel cut-off control is executed under a specified engine and vehicle operating condition and a fuel-supply recovery engine speed (N.sub.2) below which a fuel-supply recovery control is restarted so that fuel supply to the engine is recovered from the fuel cut-off control. The electronic control module variably determines a hysteresis between the fuel-cut engine speed and the fuel-supply recovery engine speed so that a deviation (N.sub.3 -N. sub.2) of the fuel-cut engine speed from the fuel-supply recovery engine speed in the locked-up state is smaller than a deviation (N.sub.1 -N.sub. 2) of the fuel-cut engine speed from the fuel-supply recovery engine speed in the open converter state.