喷油器积碳对直喷汽油机燃烧和排放的影响  

Effect of Injector Deposits on Combustion and Emissions of Gasoline Direct Injection Engine

作　　者：张文彬[1] 张周 马骁[1] 帅石金[1] Zhang Wenbin;Zhang Zhou;Ma Xiao;Shuai Shijin(State Key Laboratory of Automotive Safety and Energy,Tsinghua University,Beijing 100084,China)

机构地区：[1]清华大学汽车安全与节能国家重点实验室,北京100084

出　　处：《内燃机学报》2021年第6期488-497,共10页Transactions of Csice

基　　金：国家自然科学基金资助项目(51636003)。

摘　　要：基于汽油缸内直喷(GDI)光学机测试台架,利用高速摄影获取干净喷油器和积碳喷油器在去除尖端积碳前、后的喷油液滴吸附和缸内燃烧黄色火焰图像,并测量排气中的颗粒物排放,重点分析了在不同喷射策略下喷油器尖端积碳对直喷汽油机喷油、燃烧和排放的直接影响.结果表明:尖端积碳会显著增加喷油器顶部表面的燃油吸附,并在缸内燃烧后期产生明亮的黄色火焰,造成排气颗粒物排放恶化.对于积碳喷油器,喷油压力从10 MPa提高至20 MPa可部分缓解积碳的负面影响,但两次喷射造成了更高的黄色火焰信号强度和颗粒物排放.去除喷油器尖端积碳后,燃油吸附量减少,黄色火焰信号强度峰值减弱74%~93%,积聚态颗粒物数量浓度排放降低70%~88%,试验结果直接表明尖端积碳对GDI发动机燃烧和排放的重要影响作用.The impact of injector tip deposits on fuel injection,combustion and emissions of the gasoline direct in-jection(GDI)engine was investigated in an optical GDI engine with varying fuel injection strategies.The images of fuel adsorption on a GDI injector’s tip and the in-cylinder yellow flame were obtained by high-speed photography before and after removing the tip deposits.Meanwhile,the particulate emissions in the tailpipe were measured.The test results show that the tip deposits can significantly increase the fuel absorption on the injector tip surface after the injection and generate bright yellow flame during the later stage of in-cylinder combustion process,which deterio-rates the exhaust particulate emissions.For the fouled state,increasing the fuel injection pressure from 10 MPa to 20 MPa can alleviate the negative effect of injector deposits,but the split injection strategy results in higher yellow flame signal intensity and particulate emissions.After removing the tip deposits of the fouled injector,the amount of fuel absorbed on injector tip is reduced,the peak intensities of the yellow flame signal decrease by 74%-93%and the particle number emissions in accumulation mode decrease by 70%-88%.This indicates the important ef-fects of the injector tip deposits on GDI engine combustion and emissions.

关 键 词：汽油缸内直喷发动机 喷油器积碳 高速摄影 燃油吸附 颗粒物排放 

分 类 号：TK411.2[动力工程及工程热物理—动力机械及工程]