Abstract
As is well-known, high efficiency is an important advantage of lean burn mode of combustion engines. However, combustion variation is a bottleneck that constraints thermal efficiency improvement in lean combustion. In this paper, a combustion variation restrain control strategy with thermal efficiency optimization consideration is proposed which consists of dual control loops, the inner-loop targets on cycle-to-cycle and cylinder-to-cylinder variation evaluated by IMEP and CA50, and the out-loop is exploited to provide extremum seeking of spark advances of individual cylinder. The effectiveness of the proposed method and variation restrain performance are validated on a commercial gasoline engine test bench..
