Assist mode control system for a hybrid vehicle

• Main Authors: UKAI, ASAO, IZUMIURA, ATSUSHI, NAKAUNE, KAN, IWAMOTO, TAKASHI, WAKASHIRO, TERUO, KUMAGAI, KATSUHIRO
• Format: Patent
• Language: English; French; German
• Published: 24.09.2008
• Subjects: ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS INVEHICLES; ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OFTRANSMISSIONS IN VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GASEXHAUST OR FUEL SUPPLY OF PROPULSION UNITS, IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; BLASTING; COMBUSTION ENGINES; CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE ORDIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; CONTROLLING COMBUSTION ENGINES; ELECTRIC EQUIPMENT OR PROPULSION OF ELECTRICALLY-PROPELLEDVEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES, IN GENERAL; ENGINE PLANTS IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNALCOMBUSTION ENGINES; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES ORENGINES IN GENERAL; HEATING; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; LIGHTING; MACHINES OR ENGINES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MECHANICAL ENGINEERING; PERFORMING OPERATIONS; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TOTHE CONTROL OF A PARTICULAR SUB-UNIT; STEAM ENGINES; TRANSPORTING; VEHICLES IN GENERAL; WEAPONS

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