Investigation on spray combustion modeling for performance analysis of future low- and zero-carbon DI engine

Global warming issues and fossil fuel depletion crisis have forced transportation industry to seek clean engine fuels both liquid and gaseous. Dual-fuel mode with high-pressure direct injection (HPDI) has been recognized as mainstream method in developing flexible-fuel internal combustion engines (ICEs). But flexible-fuels’ physicochemical properties and spray combustion characteristics under HPDI have changed a lot. Unfortunately, there is currently no universal model for predicting spray combustion behaviors and analyzing performance of flexible-fuel ICEs. Therefore, this paper aims to develop a novel spray combustion model and provide optimal injection and combustion strategies for performance improvement of low- and zero-carbon HPDI ICEs. Based on balance of momentum change and vortex ring drag force, the jet spray effective injection velocity is obtained. Then the jet spray penetration under varying injection rate is solved. Finally, the developed model is established and validated experimentally, with the spray combustion characteristics of various fuels investigated. The results show that the developed model has a good accuracy and robustness for flexible-fuels’ characteristic analysis. Meanwhile, multiple-injection could increase the combustion efficiency (CE) over 10.27 % than single-injection, and CE increases with dwell time. Moreover, CE of H2 in nitrogen-oxygen (N2–O2) atmosphere is 10.15 % higher than that in argon-oxygen (Ar–O2) atmosphere.