| 摘要 |
<p>PROBLEM TO BE SOLVED: To expand the lean limit air-fuel ratio to the lean side by restraining a fluctuation in combustion pressure with respective cycles at lean combustion time. SOLUTION: A rate of changeΔP of cylinder internal pressure in a prescribed crank angle period set in an initial stage after ignition is calculated on the basis of the cylinder internal pressure with respective cylinders at lean combustion time. When the rate of changeΔP is a determining levelΔP0 or less, it is determined as the occurrence of incomplete combustion, and reignition is immediately performed. Thus, the combustion pressure is quickly increased, and the fluctuation in the combustion pressure with respective cycles at lean combustion time can be restrained so that the lean limit air-fuel ratio can be expanded to the lean side.</p> |
