高压共轨柴油机瞬变过程试验与模拟分析  

Simulation and Experiment of DI Diesel Engine Under Transient Operations

作　　者：沈照杰[1] 刘忠长[1] 田径[1] 李康[2] 刘江唯[2] 

机构地区：[1]吉林大学汽车仿真与控制国家重点实验室,吉林长春130025 [2]中国第一汽车集团公司技术中心,吉林长春130011

出　　处：《内燃机学报》2013年第5期407-413,共7页Transactions of Csice

基　　金：国家重大基础研究发展规划(973)资助项目(2013CB228402);国家自然科学基金资助项目(51206060)

摘　　要：以高压共轨柴油机为研究对象,基于瞬变试验测试结果,采用三维CFD软件模拟CA6DL2-35R柴油机瞬变过程,分析缸内当量比-温度分布及缸内油气混合均匀程度与排放变化的关系.将时间连续的瞬变过程离散为基于循环数的离散集合;从缸内高温区体积、高温区持续时间及双岛图3个方面分析瞬变过程缸内NOx排放变化趋势;引入洛伦兹曲线分析气缸内油气混合的均匀程度,并采用基尼系数曲线描述缸内油气分布均匀程度的变化趋势.研究表明:随着瞬变循环数增加,缸内当量比-温度分布向双岛图的NOx岛的递进减小,向soot岛的递进增加;缸内油气分布不均匀程度呈先增加后减小的趋势;瞬变过程第176循环与相应的50%稳态负荷点相比,缸内分布不均匀程度偏高.3D simulations on a DI diesel engine with high pressure common rail injection system under transient operations with EGR were conducted. The in-cylinder parameters of transient operations were analyzed. Experimental results based on time were converted into the discrete points based on cycle. NOz emissions were analyzed by volume, duration of in-cylinder high temperature area and 0-T diagram. Simulation results of separated transient cycle agree with that of the corresponding experimental data. NOx emissions decreases under the increasing torque process while soot emissions increase substantially as be- ing explained by 0-T diagram where in-cylinder equivalence ratio and temperature approach to the soot area and retreat to NOx area when loads increased. Uniformity of cylinder mixture was analyzed by Lorenz curve. Under transient conditions, soot emission deterioration is from the increased heterogeneity of the in-cylinder fuel-air mixture compared with steady condition.

关 键 词：柴油机 燃烧模拟 瞬变工况 缸内分布不均匀度 

分 类 号：TK427[动力工程及工程热物理—动力机械及工程]