| 摘要 |
PROBLEM TO BE SOLVED: To provide an engine with an optimum quantity of fuel feed according to fuel properties by effectively utilizing estimation results on properties of fuel which is used in calculating a fuel feed quantity. SOLUTION: In a transient state, a fuel feed quantity constitutes an input signal and an air-fuel ratio of exhaust gas constitutes an output signal. Sampling means 53 samples data of a response waveform, with respect to the air-fuel ratio of the exhaust gas generated from the feed quantity of fuel being used. Based on these input and output data, parameters of a plant model constructed beforehand are adjusted to minimize estimation errors with respect to those of a reference model. With this arrangement, an identification means 54 identifies a plant model corresponding to the fuel being used, and a calculation means 55 calculates a cut-off frequency of the identified plane model. Comparing the cut-off frequency of the plant model to that of the reference model, estimation means 56 estimates properties of the fuel being used. Based on the results of this fuel property estimation, a calculation means 57 calculates the fuel feed quantity.
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