DESCENDING SLOPE STATE DECIDING METHOD FOR INTERNAL COMBUSTION ENGINE FOR VEHICLE

摘要

PROBLEM TO BE SOLVED: To decide a vehicle descending slope state without providing a throttle sensor and to correct atmospheric pressure by only a simplified software processing at the decision time. SOLUTION: An electronic control unit(ECU) 20 decides that a vehicle is in a descending slope state of traveling on a descending slope by a decelerating operation when a value of intake pressure detected by an intake pressure sensor 21 is kept smaller than that at the time of an idle operation for prescribed time when an engine 3 having a throttle valve 9 in an intake passage 6 is operated. The ECU 20 calculates a ratio of a value of intake pressure at the time of the decision of the descending slope to a value of standard intake pressure detected in advance at the time of the decelerating operation under standard atmospheric pressure as an atmospheric pressure deviation ratio. The ECU 20 corrects atmospheric pressure before descending slope based on the deviation ratio and estimates atmospheric pressure of this time. The ECU 20 corrects fuel injection quantity and an ignition timing by the atmospheric pressure estimated value to execute each of a fuel injection control and an ignition timing control.