SECONDARY AIR SUPPLY DEVICE FOR INTERNAL COMBUSTION ENGINE

摘要

PROBLEM TO BE SOLVED: To keep optimum balance of supply quantity of secondary air and increased fuel quantity while effectively performing emission control and catalyst activation by secondary air and keeping air fuel ratio of combustion air fuel mixture in a cylinder in an appropriate range.

SOLUTION: A catalytic converter is interposed in an exhaust duct after merger of exhaust systems of each bank of a V-engine. Secondary air is supplied to the exhaust system of one bank and fuel quantity is increased for all cylinders. Feed back correction of fuel increase level is performed based on exhaust air fuel ratio at a catalyst inlet and it is monitored whether cylinder air fuel ratio becomes rich limit air fuel ratio or not based on exhaust air fuel ratio of the bank to which secondary air is not supplied. Feedback of the fuel increase level is stopped and catalyst inlet air fuel ration is made close to a target by reducing secondary air when cylinder air fuel ratio exceeds rich limit air fuel ratio.

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