Abnormal combustion risk assessment of hydrogen internal combustion engine based on AHP-entropy method

An abnormal combustion risk coefficient model was constructed based on the analytic hierarchy process (AHP) to comprehensively evaluate the abnormal combustion risk of port fuel injection (PFI) hydrogen internal combustion engine. The effects of hydrogen injection parameters on the indicator layer (abnormal combustion characteristic parameters) and the target layer (abnormal combustion risk coefficient) were investigated respectively. The results showed that by changing the hydrogen injection parameters, the maximum amount of residual hydrogen in intake port decreased by 33.4% to 41.6%. The possibility of backfire was reduced significantly. When the hydrogen injection angle was 30°−45° and the hydrogen injection flow rate was 4.36−4.96 kg/h, the in-cylinder mixture uniformity coefficient was large. The hydrogen injection parameters were favorable for organizing the combustion, but the hydrogen injection parameters could not ensure that parameters such as the incandescent area temperature were at a low level. The constructed abnormal combustion risk coefficient model could combine several characteristic parameters for effective assessment of abnormal combustion risk of hydrogen internal combustion engines. When the hydrogen injection angle was 45° and the hydrogen injection flow rate was 4.96 kg/h, all the characteristic parameters were in a reasonable range. The abnormal combustion risk coefficient decreased by 3.6% to 6.8% and the possibility of abnormal combustion was reduced. © 2022 Zhejiang University. All rights reserved.