| 摘要 |
Based on an internal EGR ratio and desired external and internal EGR ratios, an EGR valve opening degree is feedback-controlled based on a desired EGR ratio, calculated in such a way as to perform correction so that a total EGR ratio becomes constant, and an EGR effective opening area obtained through learning of the relationship between an EGR valve opening degree and an effective opening area; thus, a correct characteristic of EGR valve opening degree vs. effective opening area can be maintained and hence it is made possible to absorb variations, changes with time, and even environmental conditions, while making an EGR valve and an intake/exhaust VVT collaborate with each other; therefore, an EGR flow rate can accurately be estimated. |
