后喷策略对汽油压燃燃烧及碳烟排放的影响  

Effects of Post Injection Strategy on Gasoline Compression Ignition and Soot Emissions

作　　者：王浒[1] 左青明 王梦玉 郑尊清[1] Wang Hu;Zuo Qingming;Wang Mengyu;Zheng Zunqing(State Key Laboratory of Engines,Tianjin University,Tianjin 300072,China)

机构地区：[1]天津大学内燃机燃烧学国家重点实验室,天津300072

出　　处：《燃烧科学与技术》2021年第3期263-270,共8页Journal of Combustion Science and Technology

基　　金：国家自然科学基金资助项目(51976134;51876140).

摘　　要：针对大负荷条件下汽油压燃碳烟排放高的问题,基于三维流体力学软件CONVERGE开展了汽油压燃燃烧及碳烟生成氧化过程影响的数值模拟,系统研究了在废气再循环(EGR)结合气道喷射(PFI)情况下,后喷策略对大负荷条件下汽油压燃燃烧过程及碳烟生成氧化过程的影响规律和机制.研究结果表明,在复合喷射策略条件下,后喷使主喷油量减少从而降低了前期碳烟的产生,且后喷燃料的燃烧加速燃烧后期碳烟的氧化过程,从而使整体碳烟排放降低;在EGR率为20%、气道喷射比例为40%、主喷时刻为-8°CA ATDC、主喷-后喷间隔为10°CA、后喷油量为5 mg时,可以同时获得较高的热效率(45.959%)及较低的碳烟和NOx排放,同试验基准相比,NOx排放降低68.3%,最大压升率降低28.6%;相较于单次喷射,碳烟排放降低14.7%.For the problem of high soot emissions of gasoline compression ignition(GCI)under high load conditions,the effects of post injection strategy coupled with exhaust gas recirculation(EGR)and port fuel injection(PFI)on the combustion process and soot formation process of GCI are studied under high load conditions based on software CONVERGE.Simulation results show that the soot formation can be suppressed at the early stage because of the less DI fuel portion and the soot oxidation can be enhanced through post injection fuel at the later stage of combustion,thus lowering the soot emissions as a whole.At the EGR rate of 20%,the PFI ratio of 40%,the main injection timing of-8°CA ATDC,the main-post injection interval of 10°CA,and the post injection mass of 5 mg,soot emissions can be reduced by 14.7%compared with single injection strategy while still maintaining a high thermal efficiency(45.959%).In addition,NOx emissions can be reduced by 68.3%,and the maximum pressure rise rate can be reduced by 28.6%compared with the experimental baseline.

关 键 词：汽油压燃 碳烟排放 气道喷射 后喷策略 

分 类 号：TK41[动力工程及工程热物理—动力机械及工程]