Research on oxidation mechanism of hydrogen/syngas-methanol and its application on engine performance prediction

As a kind of promising additive fuel for spark ignition methanol engine, hydrogen/CO-rich syngas, produced by reforming methanol has attracted considerable attention because of its positive effects on engine combustion. In the current study, a chemical mechanism for hydrogen-methanol and syngas-methanol combustion was developed to predict the engine performance. The kinetic mechanisms, includes 39 species and 193 elementary reactions after reducing and optimizing the detailed chemical mechanism (Burke et al., 2016). It was proved that this mechanism can well predict the ignition delay time, laminar burning velocity and the typical species evolution of hydrogen-methanol and syngas-methanol mixtures. Moreover, the differences between the effects of hydrogen and syngas additions on the ignition delay and laminar burning velocity were analyzed quantitively. Based on the mechanism and bench test data, computational investigations on the knock and combustion characteristics of methanol, hydrogen/methanol and syngas/methanol stoichiometric operation engines were conducted. In order to further improve the comprehensive thermal efficiency, the engine operation scheme accompanied with a methanol-reformer was proposed, and the syngas blending ratio can reach 0.076 within the knock limitation. In this way, the corresponding comprehensive thermal efficiency of the system is increased by 1.96% compared with the original methanol engine.