| 郑尊清，王献泽，王浒，朱赞，邓远海，韦钻国.基于当量燃烧的天然气发动机燃烧室优化研究[J].内燃机工程,2020,41(4):1-8. |
| Optimization Study on Combustion Chamber of a Stoichiometric Combustion Natural Gas Engine |
| DOI：10.13949/j.cnki.nrjgc.2020.04.001 |
| Key Words:natural gas engine stoichiometric combustion squish ratio compression ratio thermal efficiency |
| Author Name | Affiliation | | ZHENG Zunqing,WANG Xianze,WANG Hu,ZHU Zan,DENG Yuanhai,WEI Zuanguo | 1.State Key Laboratory of Engines, Tianjin University, Tianjin 300072, China
2.Guangxi Yuchai Machinery Co., Ltd., Yulin 537000, China |
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| 摘要点击次数: 5084 |
| 全文下载次数: 1991 |
| Abstract:A comparison test of the effect of piston with different squish ratios and compression ratios on combustion thermal efficiency and exhaust emissions was carried out on a stoichiometric combustion natural gas engine with exhaust gas recirculation(EGR) strategy. Results showed that at the speed of 1400 to 1800r/min and with 50% or 75% of rated load, increasing the EGR rate extended the knock boundary, thus advancing the angle of 50% mass fraction burned(CA50), and increasing the indicated thermal efficiency. At the speed of 2300r/min and with 75% or 100% of rated load, increasing the EGR rate could significantly extend the combustion duration, thus retarding the CA50 and reducing the thermal efficiency. On the other hand, increasing the compression ratio and appropriately enhancing the squish ratio was beneficial to improve the turbulent motion in the cylinder and accelerate the flame propagation speed of natural gas, so that the CA50 was closer to the top dead center, which improved the thermal power conversion efficiency coupled to the increase of the highest indicated thermal efficiency by 0.24% and hence NOx and CH4 emissions by 2.30g/(kW·h) and 0.55g/(kW·h), respectively. Further increase in squish ratio would be limited by knock, resulting in delayed maximum brake torque timing and extended combustion duration, which would reduce the maximum indicated thermal efficiency by 0.51% and decrease NOx and CH4 emissions by 2.20g/(kW·h) and 0.44g/(kW·h), respectively, coupled to the increase of CO by 0.36g/(kW.h). Therefore, there was a range of squish ratio that needs to be optimized. |
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