Effects of different excess air coefficients and spark timing on the performance and emissions of a heavy-duty hydrogen SI engine under lean conditions
Year: 2025
Type: article
Abstract: This study utilized CONVERGE software to establish a three-dimensional combustion chamber simulation model for a 12.5 L port fuel injection (PFI) heavy-duty hydrogen-fueled internal combustion engine and validated the reliability of the model through experimental data. Based on this simulation model, the effects of excess air coefficient (λ = 2.0–2.3) and spark timing (SPK) on combustion, performance, and emission characteristics were systematically investigated under a 1200 r/min operating condition. The results indicate that, under fixed SPK timing conditions, as the excess air coefficient increases from 2.0 to 2.3, combustion intensity is significantly weakened, with peak cylinder pressure and heat release rate (HRR) decreasing by 12.3 % and 39.3 %, respectively, while NOx emissions decrease by 88 %. The influence of intake pressure on the combustion process increases with increasing λ. Advancing the SPK timing significantly improves combustion efficiency. When λ is 2.0 and 2.3, the corresponding cylinder pressure increases by 23.7 % and 10.6 %, respectively, and the HRR increases by 27.4 % and 10.4 %, respectively. However, this results in increased NOx emissions. Delaying the SPK timing causes NOx emissions to drop sharply, with a maximum reduction of 50 %. The combined effect of advanced SPK timing and a high excess air coefficient (λ ≥ 2.3) leads to a shift in the combustion phase. When this is coupled with the piston’s upward compression effect, it effectively increases cylinder pressure and enhances power output. This study provides theoretical support for understanding the performance of large-displacement hydrogen-fueled internal combustion engines under lean-burn conditions.
Source: Results in Engineering
Authors: Songyue Chai, Xianyu Jia, Lifeng Ma, Qisheng Zhang, Yongfeng Liu
Institution: Taiyuan University of Science and Technology
Language: English
Subfield: Fluid Flow and Transfer Processes
Field: Chemical Engineering
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,940
OpenAlex ID: W4417488028