SECONDARY AIR FEEDING DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a secondary air feeding device to keep a fuel feed amount for secondary air, while a secondary air ratio is maintained at an optimum value. SOLUTION: The secondary air feeding device feeds secondary air to an exhaust pipe 14 of an internal combustion engine. The device comprises: an air pump 10 to produce secondary air and deliver it to the exhaust pipe 14; and air flow meter 16 situated between the air pump 10 and the exhaust pipe 14 and measuring a flow rate of secondary air; a combination valve 12 with a check valve situated between the air pump 10 and the exhaust pipe 14 and ventilating or shutting-off; and a flow rate control unit 20 to compute an air pump manipulated variable and control the air pump 10 based on a difference between a target secondary air flow rate and a measured secondary air flow rate, when secondary air is ventilated by controlling the combination valve with a check valve. COPYRIGHT: (C)2004,JPO