Combustion Simulation of Direct Injection CI Engine Operating on Dual Fuel Using CFD

In general, the alternative fuels such as hydrogen and methane when added to internal combustion engine improve efficiency and decrease emissions. This is due to improving homogeneity of the mixture, high heating value, fast flame propagation, and less emissions. Conversely, the hydrogen has high self-ignition temperature compared to neat diesel fuel, high in-cylinder pressure and temperature, and peak heat release rate results in combustion knock. The present investigation describes the effect of hydrogen and methane addition to diesel fuel in dual mode for direct injection CI engine with multi-stages fuel injection mode. The intermittent strategy has been adopted in the simulation to avoid difficulties associated with abnormal combustion inside the combustion chamber and to reduce the amount of NO and soot exhausted from diesel engines. A single cylinder 4- strokes engine has been simulated using computational fluid dynamics FLUENT code. The simulation carried out for three testing fuels: neat diesel fuel, dual hydrogen-diesel, and dual methane-diesel. The total mixture of fuel mass was injected in three stages. The engine speed is 1500 rpm and run at full load. The simulation outputs such as heat release rate, in-cylinder pressure, in-cylinder temperature, were used to evaluate the effect of the alternative fuel addition on the engine performance. The results showed that the addition of a certain amount of gaseous fuel to diesel fuel in CI engine gave a significant increase in the peak in-cylinder pressure, and heat release rate compared to neat diesel fuel operation results in increase of engine efficiency and decrease of pollution.