Study on dual injection strategy of diesel ignition ammonia/hydrogen mixture fuel engine

The diesel ignition ammonia/hydrogen mixed fuel engine adopts the dual injector mode. This paper studies the dual injection strategy of the engine through simulation and selects the best combination of dual injection timing to optimize the combustion and emission performance of the diesel ignition ammonia/hydrogen mixed fuel engine. The results show that under the dual fuel injection strategy, with the delay of fuel injection timing, the power and economy of the engine gradually decline, HC, soot, CO, and N2O emissions in the exhaust gas increase progressively, while NOx emission concentration significantly decreases. However, after using ammonia/ hydrogen mixed fuel, the engine's ammonia escape and hydrogen escape are very low. The emission of HC, soot, and CO in the exhaust gas is also low. At the same time, the engine's NOx emission can meet the emission standards of Tier II when any fuel injection combination is used. At D708/A/H712, the NOx emission of the engine can meet the emission standard of Tier III. One of the purposes of using ammonia as an alternative fuel for diesel is to reduce CO2 emissions in the exhaust gas and prevent further global warming. But the impact of N2O on global warming is nearly 298 times that of CO2. At D698/A/H698, the engine has the best power performance and economic performance. At the same time, N2O emissions are low, but NOx emissions are relatively high. Considering that N2O emissions cause significant harm to the greenhouse effect, D698/A/H698 is selected as the best fuel injection timing combination in this paper. The research results in this paper can promote the devel-opment of ammonia fuel in the field of the internal combustion engine and provide theoretical guidance for the practical application of ammonia.