【摘要】 针对柴油-天然气双燃料发动机的关键共性技术问题以及双燃料发动机低负荷工况热效率低、CH4排放高等现象,从燃烧室优化设计角度入手,通过增强缸内湍流流动改善混合气燃烧,进而提高发动机的经济性,降低CH4排放性。利用STAR-CD软件建立了数值模拟平台,并进行了有效性验证。通过对原机1 335r/min,218N·m工况下缸内微观燃烧参数场变化进行分析,设计了一种新型燃烧室以增强缸内流动、加快燃烧速度。研究结果表明,和原机相比,新型燃烧室能够有效地增强缸内湍流流动,最高燃烧压力提高了近25%,天然气剩余率从28.6%降到0.5%,提高了燃烧的质量,改善了发动机的经济性和排放性。更多还原

【Abstract】 Based on the common issues of diesel-natural gas dual fuel engine existing in the key technologies and the phenomena of low thermal efficiency and high CH4 emission,the fuel economy improved and the CH4 emission reduced through strengthening the in-cylinder turbulent flow and improving the mixture combustion in terms of combustion chamber optimization.The numerical simulation platform was established with STAR-CD software and its verification was conducted.Then a new type of combustion chamber was designed to improve the in-cylinder flow and combustion rate through analyzing the changes of microscopic combustion parameters in the original configuration under the load conditions of 218N·m at 1 335r/min.The results show that the new combustion chamber can effectively strengthen the in-cylinder turbulent flow and hence the maximum combustion pressure increases by nearly 25% and the natural gas residual rate decreases from 28.6%to 0.5%.Finally,the optimal combustion quality is determined and the economy and emissions improve.更多还原