| 摘要 |
PROBLEM TO BE SOLVED: To improve responsiveness of an opening of an EGR valve in the case where an operating condition of an engine is rapidly changed, and prevent an exhaust recirculation ratio from varying from a target exhaust recirculation ratio largely, in a diesel engine provided with an exhaust recirculation device. SOLUTION: A correction duty calculating means M3 calculates a correction duty D1 for conversing a fresh air flow amount Qair to a target fresh air flow amount Qobj on the basis of a deviation between the fresh air flow amount Qair and the target fresh air flow amount Qobj, and a reference duty calculating means M4 calculates a reference duty D2 for obtaining the target fresh air flow amount Qobj on the basis of a fuel injection amount Qinj and engine rotating speed Ne so as to control an opening of the EGR valve 19 on the basis of a final duty to which the correction duty D1 and the reference duty D2 are added. It is thus possible to reconcile responsiveness and conversing performance by assembling feed back control by the correction duty D1 and feed forward control by the reference duty D2 with each other.
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