| 摘要 |
PROBLEM TO BE SOLVED: To suppress heat damage inflicted on an exhaust gas purification catalyst attached to the exhaust passage of an internal combustion engine irrespectively of an increase in a fuel injection quantity, and to enable the catalyst to be promptly heated at a time of a cold start.SOLUTION: Exhaust gas throttle means is provided downstream of an exhaust gas purification catalyst in an exhaust passage, and the exhaust gas throttle means is operated to have a first opening at timing right after engine start, operated to have a second opening larger than the first opening in a medium-revolving-speed or medium-load operation region, and operated to have a third opening larger than the second opening in a high-revolving-speed or high-load operation region. |
