| 摘要:为了改善柴油引燃天然气发动机的排放性能，开展废气再循环（EGR）废气组分比例对柴油引燃天然气发动机燃烧过程的影响研究。针对一款直列六缸四冲程柴油引燃天然气发动机进行台架试验，基于试验数据搭建并标定CFD仿真模型，在此基础上研究不同质量比的EGR废气组分（CO2和水蒸气）对柴油引燃天然气发动机燃烧与排放特性的影响。结果表明，引入CO2和水蒸气后缸内压力和温度均出现明显下降， EGR废气组分中水蒸气质量分数越高，缸内压力和温度越低。总体来说，CO2和水蒸气对发动机排放特性的影响明显大于对燃烧特性的影响。当引入EGR废气组分全部为水蒸气时，缸内氮氧化物（NOx）排放最低（920×10-6）。当CO2和水蒸气质量分数相同时，CO排放相较于初始状态下降11%。 |
| 关键词: 双燃料发动机 燃烧 排放 CFD模拟 |
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| Effect of the Proportion of EGR Components on Combustion and Emission Characteristics of Diesel-ignited Natural Gas Engine |
| WANG Xun,LIU Qi,LIU Jingping,FU Jianqin |
| Chongqing Shikai Automobile Technology Co., Ltd., Chongqing 401120, China;Research Center for Advanced Powertrain Technology, Hunan University, Changsha 410082, China |
| Abstract:In order to improve the emission performance of diesel-ignited natural gas engines，the effect of exhaust gas recirculation（EGR）component ratios on the combustion process of diesel-ignited natural gas engines was investigated.A bench test was conducted on an inline six-cylinder four-stroke diesel-ignited natural gas engine.Based on the test data，a CFD simulation model was constructed and calibrated to investigate the effects of different mass ratios of EGR components（CO2 and water vapor）on the combustion and emission characteristics of the diesel-ignited natural gas engine. The results show that both the in-cylinder pressure and temperature decrease after the introduction of CO2 and water vapor significantly.Especially as the mass ratio of water vapor in the EGR components increases，the in-cylinder pressure and temperature decrease.Overall，the effect of CO2 and water vapor on engine emissions is significantly greater than on combustion characteristics.NOx emissions are lowest （920×10-6）when all the introduced EGR components are water vapor.When the mass fractions of CO2 and water vapor are the same，carbon monoxide（CO）emissions are reduced by 11% compared to the initial state. |
| Key words: duel fuel engine combustion emission CFD simulation |
