| 摘要 |
A method of controlling a spark-ignition engine including an ignition plug for spark-igniting mixture gas inside a cylinder in an engine body, and an effective compression ratio changing module for changing an effective compression ratio of the engine body is provided. The method includes estimating, based on engine speed, engine load, and environmental conditions, a limit effective compression ratio serving as a maximum effective compression ratio where pre-ignition does not occur, calculating a current effective compression ratio, calculating a value obtained by subtracting the effective compression ratio from the limit effective compression ratio, as a margin before pre-ignition occurs, and decreasing, when the margin is below a predetermined minimum margin, the effective compression ratio of the engine body by using the effective compression ratio changing module so that the margin is increased to be above the minimum margin, which is set constant regardless of at least environmental conditions. |
