Quantitative evaluation method for determining the misfire boundary of n-butanol premixed charge compression ignition

This study proposes a novel approach for determining the misfire boundary of an engine. It skillfully builds a nonlinear mapping correlation between post-cylinder performance and in-cylinder combustion state parameters. The accuracy of the misfire boundary determination is improved by using the boundary accuracy constraint and the abrupt change point detection method of the curve. The method is verified by experiments on a six-cylinder diesel engine in which a single cylinder is fueled with n-butanol. The results show that the method can accurately identify the complete misfire and normal combustion boundaries of n-butanol premixed charge compression ignition under different conditions. The uncertainty of the real value evaluation of the boundary is reduced by more than three times as compared with the conventional single-parameter approach. A map diagram of the n-butanol combustion boundary at 1300 rpm is obtained using this method. • A evaluation method was proposed to determine the misfire boundary of CI engine. • Two parameters with the smallest difference in boundaries were selected. • Accuracy constraint of boundary was considered. • The accuracy and applicability of the method was verified.