| 摘要 |
PROBLEM TO BE SOLVED: To control EGR quantity to its adequate value even during transient operation without being influenced by any environmental change by setting a target EGR quantity absorbed in cylinder(s) based upon the intake air quantity and the set target EGR rate of an engine. SOLUTION: An intake air flow is found out from the output value of the intake air flow shown by an air flow meter 16 by means of a conversion table. By multiplying the found cylinder intake air quantity with a target EGR rate, the target EGR quantity to the cylinder(s) is found out. Thus while the target EGR quantity is calculated so as to apply advance treatment to each delayed amount, a required flow passage area of an EGR passage is found out to know the control value of an EGR control valve 9. Next, a throttle valve 31 is closed for the purpose of improving exhaust gas and executing noise countermeasure principally during idling and/or low load operation and simultaneously the opening of the EGR control valve 9 is controlled to carry out EGR control. |
