| 摘要 |
PROBLEM TO BE SOLVED: To improve control accuracy of air-fuel ratio feedback control by accurately calculating dead time included from a fuel injection means to an air-fuel ratio detecting means. SOLUTION: A dead time basic value k0 is calculated in an (a1 section) on the basis of an intake air quantity. An exhaust temperature correction coefficient a is calculated in an (a2 section) on the basis of the intake air quantity and an engine rotating speed and the dead time k is calculated in an (a3 section) by multiplying the dead time basic value k0 by the exhaust temperature correction coefficient a. Then, in an (a4 section), an air-fuel ratio after the dead time k is predicted from a detected air-fuel ratio and is output. Parameters of a plant model representing from the fuel injection means to the air-fuel ratio detecting means are estimated one after another on the basis of a feedback control amount and the predicted air-fuel ratio after the dead time k. A control gain is calculated by using these estimated parameters and the feedback control amount is calculated by using the calculated control gain. COPYRIGHT: (C)2004,JPO
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