Effects of Combustion Characteristic Parameters on Emission Performance in Ammonia-Hydrogen Internal Combustion Engine

<div class="section abstract"><div class="htmlview paragraph">Under the background of the global dual carbon target, ammonia and hydrogen as the carbon-free fuel, have become a research hotspot for internal combustion engines. The existing researches mainly focus on the combustion characteristics influenced by equivalence ratio, hydrogen jet ignition and so on, while the relationship between combustion and emission characteristics should be also paid more attention. In this paper, the impact of combustion characteristic parameters on engine emissions is investigated by GT-power. The simulation model is based on a single cylinder engine with an active pre-chamber. Meanwhile, combustion characteristic parameters, in terms of CA50, combustion duration, CA10-CA50 and CA50-CA90 are set referred to the research of hydrogen jet ignition ammonia-hydrogen internal combustion engines. The results shown that there is compelling correlation between combustion parameters and specific emission profiles in ammonia-hydrogen internal combustion engines. Notably, delayed CA50 leads to a marked reduction in NO<sub>X</sub> emissions, accompanied by a significant escalation in N<sub>2</sub>O emission concentrations. Extending the combustion duration results in decreased NO<sub>X</sub> emissions but increases N<sub>2</sub>O emission concurrently. Lengthening CA10-CA50 increases NO<sub>X</sub> emission concentrations disproportionately while mitigating N<sub>2</sub>O formation. Conversely, prolonging CA50- CA90 precipitates a sharp decline in NO<sub>X</sub> emissions alongside heightened N<sub>2</sub>O emission. Remarkably, NH<sub>3</sub> emission concentrations remain relatively unaffected by variations in these combustion parameters, suggesting a stronger dependency on equivalence ratio and hydrogen mole fraction. Drawing upon in-cylinder temperature dynamics, this study elucidates the mechanisms underlying emission formation in response to combustion parameters modifications.</div></div>