| abstract |
The control system of the present invention is provided in a hybrid vehicle withna combustion engine (E) for outputting a driving force, an electric motor (M) forngenerating a force for assisting the output from the engine, depending on the drivingnconditions, a power storage unit (22) for storing electric energy generated by the motornacting as a generator using the output from the engine and electric energy regenerated bynthe motor when the vehicle decelerates. The control system comprises: an output assistndetermination device (S122, S135) for determining, based on a determination thresholdnvalue (MTHAST, MAST, MASTTH) as the standard, whether to assist the output fromnthe engine by the motor, depending on the driving conditions of the vehicle; an air-fuelncontroller (12) for changing the air-fuel ratio of the mixture, which is to be supplied tonthe engine, to a condition leaner or richer than the stoichiometric air-fuel ratio; andetermination threshold value changer (S251, S301) for changing the determinationnthreshold value, depending on whether the air-fuel ratio of the mixture is leaner or richernthan the stoichiometric air-fuel ratio; and a determination threshold value changenprohibiting device (S254, S304) for prohibiting the operation of the determinationnthreshold value changer when the air-fuel controller changes the air-fuel ratio of thenmixture from a condition leaner than the stoichiometric air-fuel ratio to a conditionnricher than the stoichiometric air-fuel ratio. |