Effects of H2 addition on combustion and exhaust emissions in a diesel engine

The effect of the addition of H2 on combustion and emission characteristics of Cummins ISM370 diesel engine was investigated. The cylinder pressure and heat release rate were tested under 70% load with the addition of 6% H2 to the engine. On this basis, AVL FIRE software was used to construct numerical model of the engine at 70% load with the addition of 6% H2. The simulation results and experimental results were compared, and the results gave a good consistency. Whereby, the numerical model of Cummins ISM370 engine was verified. Moreover, simulated the pressure, heat release rate, NO emissions and particulate matter (PM) emissions at 70% load with the addition of H2 from 6% to 20%, then analyzed the effect of the addition of different H2 on combustion and emission characteristics of the engine. The results showed that the cylinder pressure and heat release rate first increased then decreased with the enhancement of H2 addition, NO emissions increased, while PM emissions decreased. Both the pressure and heat release rate reached the maximum value at the addition of 17% H2. Thus, this paper provided a method to investigate the effect of the addition of H2 on the performance of diesel engine and how to get a best ratio of H2 addition.