| 摘要 |
PROBLEM TO BE SOLVED: To prevent an actual EGR state value from largely differing from a target EGR state value because of an inadequate feedback correction value immediately after change of an operating condition of an internal combustion engine, when feeding back an opening degree of an EGR valve so that the actual EGR state value corresponds to the target EGR state value. SOLUTION: The EGR control device sets an EGR valve opening degree command valueθi to a value (θb+FB) obtained by adding a feedback correction value FB based on a proportional term FBp and an integral term FBi of a difference dRegr between a target EGR ratio value Regrt and an actual EGR ratio value Regract to an EGR valve opening degree reference valueθb as a steady-state adapted value of an EGR valve opening degree (S650), and controls the EGR valve so that the actual EGR valve opening degree value becomes the EGR valve opening degree command valueθi. The integral term FBi is multiplied by a correction coefficientαset by considering the fact that a convergence value of the feedback correction value FB in a steady-state operating condition changes when the EGR valve opening degree reference valueθb changes. Thus, the integral term FBi is corrected whenever the EGR valve opening degree reference valueθb changes. COPYRIGHT: (C)2008,JPO&INPIT
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