Effect of Ethanol Reforming Gas Combined with EGR on Lean Combustion Characteristics of Direct Injection Gasoline Engine
2022-01-0521
03/29/2022
- Event
- Content
- Ethanol reforming gas combined with EGR technology can not only improve thermal efficiency, but also reduce pollutant emission under lean combustion condition. In this paper, the effects of ethanol reforming gas and EGR on the combustion and emission characteristics of a direct injection gasoline engine under lean combustion are further discussed by means of experiment and simulation. The results find that compared with pure gasoline, the combustion speed of 20% hydrous ethanol is significantly faster, the combustion duration is shortened by 6 CA, the cylinder pressure and heat release rate are slightly increased, as well as the CO and HC emissions are reduced, based on the experiments. Moreover, the influence of ethanol reforming gas on the performance of a direct injection gasoline engine under rarefied combustion condition is investigated and analyzed by GT-Power and CONVERGE simulation. The results show that the increase of excessive air coefficient leads to the decrease of cylinder pressure and the delay of the peak time of cylinder pressure. After introducing 20% reforming gas, the combustion environment is improved, the maximum cylinder pressure and pressure rise rate can increase by 35%, the flame development period and rapid combustion period are shortened obviously, the cyclic variation coefficient of the maximum cylinder pressure under dilution condition is reduced by 3.5%, and the thermal efficiency is further improved. Besides, the introduction of EGR reduces the combustion pressure and temperature. The peak cylinder pressure decreases by 42.5% and the rapid combustion period increases by 19° CA with 20% EGR. The synergistic effect of reforming gas can effectively alleviate the combustion deterioration. The introduction of 5% EGR can reduce the combustion cycle variation caused by lean-burning, and effectively improve the NOx emission caused by the mixture of ethanol reforming gas in lean-burning condition.
- Citation
- Shi, X., Qian, W., Duan, Y., Jiang, Y. et al., "Effect of Ethanol Reforming Gas Combined with EGR on Lean Combustion Characteristics of Direct Injection Gasoline Engine," SAE Technical Paper 2022-01-0521, 2022, .