| 摘要 |
<p>PROBLEM TO BE SOLVED: To control the air-fuel ratio of an exhaust gas to a target air-fuel ratio by appropriately controlling an introduction amount of a secondary air in a system for introducing the secondary air to an exhaust system. SOLUTION: A state variable quantity output part P1 determines a state variable quantity XT (k)=[λ(k), SAIR (k-3), SAIR (k-2), SAIR (k-1)] in the state of feed back-controlling an air-fuel ratioλ(k) to a target air-fuel ratioλTG. In the formula, SAIR represents a feed back correction coefficient of a secondary air introduction amount and k-3, k-2 and k-1 represent the number of control from a first sampling starting respectively. A cumulative part P2 determines an integration item ZI (k) by accumulating a deviation of the air-fuel ratioλ(k) detected by an air-fuel ratio sensor and a target air-fuel ratioλTG. A control quantity calculation part P3 operates a feed back correction coefficient SAIR (k) of the present secondary air introduction amount from the state variable quantity XT (k) outputted from the state variable quantity output part P1 and the integration item ZI (k) determined in the cumulative part P2.</p> |
