基于循环分析的发动机快速起动瞬态燃烧特性  

Characteristics of Combustion and Emissions During Engine Transient Quick Cranking Start Based on Cycle-by-Cycle Analysis

作　　者：于水[1] 董光宇[2] 高原[2] 吴志军[2] 李理光[2] 

机构地区：[1]上海交通大学动力与机械工程教育部重点实验室,上海200240 [2]同济大学汽车学院,上海200092

出　　处：《内燃机学报》2008年第5期404-409,共6页Transactions of Csice

基　　金：国家重点基础研究计划项目(2007CB21005);国家863项目(2006AA11A130);上海市产学研联盟项目(05dZ11C01);上海市重点学科建设项目(B303)

摘　　要：针对一台进气道喷射式的汽油机搭建了快速起动-停机模拟测试平台。采用基于循环分析的方法,对比了在原车小电机拖动起动和采用模拟ISG(起动/发电一体化)大电机高拖动转速起动时发动机的瞬时转速、循环进气量、点火时刻、残余废气系数、燃烧持续期、排气温度以及瞬态碳氢排放浓度的变化规律。结果表明:在起动的初始阶段,快速起动时循环进气量减少,点火时刻推迟,残余废气系数增加,燃烧持续期变长,排气温度升高;快速起动与原机起动相比,热机状态下燃烧和排放特性的差异较冷机时大;冷机快速起动首循环失火引起碳氢排放浓度增加,热机快速起动碳氢排放浓度剧增并在第5循环达到最大值。A test bench to simulate the quick start of the engine for the start/stop HEV system was set up. The transient parameters during the start process, like the instantaneous speed, the intake air charge per cycle, the ignition timing, the residual gas fraction, the exhaust temperature, the transient HC concentrations, were studied under both cold and hot conditions by means of cycle-by-cycle analysis. During the initial several cycles, the intake air charge per cycle is decreased and the ignition timing is retarded, the residual gas fraction and combustion duration as well as the exhaust temperature are increased. Under the cold condition, combustion and emission characteristics show the smaller difference between the quick start and the original start compared with that under the hot condition. Under the cold condition, the first cycle is misfired at high cranking speed, leading to high HC concentrations at the first cycle. For the quick start under the hot condition, HC concentration increases significantly at the initial several cycles and reaches the peak value at the 5th cycle.

关 键 词：混合动力汽车 高拖动转速起动 循环分析 瞬态排放 

分 类 号：TK421.2[动力工程及工程热物理—动力机械及工程]