缸内直喷灵活燃料发动机性能和燃烧特性的研究  

Performances and Combustion Characteristics of a Spark-Ignited Direct-Injection Flexible Fuel Engine

作　　者：黄勇成[1] 周龙保[1] 刘圣华[1] 

机构地区：[1]西安交通大学能源与动力工程学院,西安710049

出　　处：《燃烧科学与技术》2003年第6期501-506,共6页Journal of Combustion Science and Technology

基　　金：国家重点基础研究资助项目(2001CB209206);西安交通大学自然科学基金资助项目.

摘　　要：根据所测的示功图和排放结果,分析了一台采用火花点火、缸内直喷周向分层燃烧系统,能够灵活燃用甲醇、乙醇和汽油的发动机的性能和燃烧特性.研究表明,由于采用分层燃烧,灵活燃料发动机具有与直喷柴油机相当的热效率,在负荷特性上,燃用醇类燃料和汽油时的NOx排放分别仅为柴油机的10%～40%和21%～78%,CO排放低于1%,HC排放略高于柴油机,燃用醇类燃料时能实现无烟燃烧,燃用汽油时仅在高负荷时存在少许碳烟.灵活燃料发动机的燃烧由预混燃烧与扩散燃烧组成,具有非常快的燃烧速率,上止点后3～5°CA就燃烧完50%燃料,燃烧持续期在28～37°CA范围内,甲醇的燃烧速率最快,汽油的燃烧速率在低负荷时比乙醇稍快,在高负荷时比乙醇慢.This paper analyzes the performances and combustion characteristics of a flexible fuel engine (FFE) with a new type of spark-ignited direct-injection circularly stratified-charge (DICSC) combustion system. This engine can operate on methanol, ethanol or gasoline. The results show that the FFE has the advantages of high thermal efficiency equivalent to that of direct injection diesel engine due to adopting the mixture stratification. NOx emissions for alcohol and gasoline operation are only 10%-40% and 21%-78% of those of the diesel engine respectively at load characteristics. In the FFE, the CO emission is lower than 1%, and HC emission is slightly higher than that of the diesel engine. Smokeless combustion can be realized for alcohol operation at any operating conditions, and there exists little smoke emission for gasoline operation only at a high load. The calculated heat release rate of the FFE shows that the combustion process consists of premixing and diffusion stages and the combustion proceeds very stably and rapidly. Its cycle-to-cycle variation is lower than 6%. 50% of fuel burns out while the crank angle is situated at 3-5 degrees after top dead center, and the combustion duration is within 28-37 degrees crank angle. The combustion rate for methanol operation is higher than that for ethanol or gasoline operation. The combustion rate for gasoline operation is slightly higher at a low load and lower at a high load than that for ethanol operation.

关 键 词：缸内直喷 灵活燃料发动机 燃烧特性 排放特性 

分 类 号：TK42[动力工程及工程热物理—动力机械及工程]