Effects of Pre-injection Strategy Coupled With LIVC on the Performance of Dual Fuel Engine Under Heavy Load Conditions

Based on three-dimensional Computational Fluid Dynamics (CFD) simulation software, a natural gas/diesel dual-fuel engine combustion chamber model was constructed, and the effects of different replacement rates and pre-injection strategies coupled with late intake valve closing (LIVC) and exhaust gas recirculation (EGR) on the engine under heavy load conditions were studied. The impact of the work process. The results show that the replacement rate of natural gas is difficult to increase under heavy load conditions, and the in-cylinder combustion is poor at 90% replacement rate, and CO and CH4 are at a high level; the pre-injection strategy can effectively improve the combustion characteristics of the engine at 90% replacement rate., When the pre-injection ratio (PIR) is 50% and the pre-injection timing (PIT) is fixed at -30℃A ATDC, the maximum cylinder pressure and cylinder temperature are increased by 27.3% and 14.4% respectively compared with single injection, and CO, CH4 emissions were reduced by 64.1% and 84.7% respectively, but NO emissions increased; after adding LIVC and EGR strategies, NO emissions can be effectively reduced, but CO and CH4 emissions increased; with the increase of LIVC and EGR rates, NO emissions show a decreasing trend; when the LIVC is 15℃A and the EGR rate is 10%, the NO, CO, and CH4 emissions are all lower than a single injection at a natural gas replacement rate of 90%. © 2022, Science Press. All right reserved.