Simulation Study of the Effect of Nozzle Position and Hydrogen Injection Strategy on Hydrogen Engine Combustion Characteristic 2023-01-7018

Hydrogen energy is a kind of secondary energy with an abundant source, wide application, green, and is low-carbon, which is important for building a clean, low-carbon, safe, and efficient energy system and achieving the goal of carbon peaking and being carbon neutral. In this paper, the effect of nozzle position, hydrogen injection timing, and ignition timing on the in-cylinder combustion characteristics is investigated separately with the 13E hydrogen engine as the simulation object. The test results show that when the nozzle position is set in the middle of the intake and exhaust tracts (L2 and L3), the peak in-cylinder pressure is slightly higher than that of L1, but when the nozzle position is L2, the cylinder pressure curve is the smoothest, the peak exothermic rate is the lowest, and the peak cylinder temperature is the lowest. When the ignition timing is consistent, with the delay of hydrogen injection timing, the peak in-cylinder pressure decreases and the peak phase remains the same, the peak in-cylinder temperature and peak exothermic rate increase, and the peak phase is advanced; the stall period is the shortest when the hydrogen injection timing is 120°CA BTDC; and the combustion DOC is the most stalled when the hydrogen injection timing is 160°CA BTDC. When the hydrogen injection timing is consistent with the advance of the ignition timing, the peak of in-cylinder pressure and in-cylinder temperature increases, the stall period of in-cylinder combustion increases, the pre-burn period shortens, and the post-burn period shortens. When the ignition advance angle is 15°CA BTDC, the lowest heat release rate is 130 J/°CA, and when the ignition advance angle is 25°CA BTDC, the highest heat release rate is 208 J/°CA.