Patent ID: 8087237

Claim:
A secondary-air supply system for an internal combustion engine, comprising: a catalyst provided in an exhaust passage and configured to purify exhaust gas from the engine; a secondary-air supply source and a secondary-air valve provided in a secondary-air passage connected upstream from the catalyst; a secondary-air supply device configured to drive the secondary-air supply source and to open the secondary-air valve to supply secondary air to the exhaust passage upstream from the catalyst; and a secondary-air supply controller configured to control the secondary-air supply device to drive the secondary-air supply source and to open the secondary-air valve under a warm-up condition of the engine and under a high-load operating condition having a high flow rate of the exhaust gas, the high-load operating condition being different from the warm-up condition; wherein the secondary-air supply source is configured to provide an amount of air sufficiently large to avoid sticking of the secondary-air valve but sufficiently small to have a negligible effect on the exhaust gas temperature under a high load operating condition.