基于浓度与活性分层的汽油小负荷压燃研究  

A study of gasoline compression ignition at low load based on concentration and activity stratification

作　　者：张蕾[1] 张珊珊[1] 邬斌扬[1] 苏万华[1] Zhang Lei;Zhang Shanshan;Wu Binyang;Su Wanhua(State Key Laboratory of Engines,Tianjin University,Tianjin 300350,China)

机构地区：[1]天津大学先进内燃动力全国重点实验室,天津300350

出　　处：《内燃机学报》2025年第2期97-106,共10页Transactions of CSICE

基　　金：国家重点研发计划资助项目(2022YFE0100100);国家自然科学基金资助项目(51921004).

摘　　要：汽油压燃发动机具有高效清洁运行的潜力,基于自行搭建的汽、柴油双燃料发动机试验平台及缸内燃烧数值模拟方式,研究了汽油双、单歧管喷射策略及柴油单次、两次直喷策略所产生的燃料分层对汽油压燃小负荷燃烧的优化效果.结果表明:在转速为1500 r/min、燃料热量为610.4 J/cyc的小负荷工况下,单歧管策略的缸内混合气浓度分层程度显著高于双歧管策略,有利于火核产生,提升着火性能,但燃烧效率低下.因此采用直喷微量柴油的策略使混合气活性大幅提升,活性基团产生与消耗速率加快,不同直喷策略导致混合气燃烧特性产生变化.在汽油预混率为86%的工况下,柴油早喷(-160°CAATDC)时的平均指示压力和指示热效率(ITE)分别为0.53 MPa和49.41%,NOx、CO和总碳氢化合物(THC)排放水平降低,但压力升高率超限.优化喷射策略,采用多次直喷可灵活调控混合气浓度与活性分布,延缓放热进而降低压力升高率.在一次柴油早喷量为1.9 mg/cyc、二次柴油直喷量为1.0 mg/cyc时,指示热效率进一步提升至49.55%.Gasoline compression ignition engines have the great potential for efficient and clean operation.Based on a self-built gasoline-diesel dual fuel engine test bench and an in-cylinder combustion numerical simulation,the effect of fuel stratification,generated by the gasoline dual or single manifold injection strategies and the diesel single or multiple in-cylinder injection strategies respectively,on gasoline compression ignition combustion at low load was studied.The results show that under the low load condition with a speed of 1500r/min and a fuel calorific value of 610.4 J/cyc,the concentration stratification degree of the gasoline single port injection strategy is significantly higher than that of the dual ports injection strategy.The strategy of direct injection of micro diesel greatly increases the activity of the mixture,accelerates the generation and consumption rate of active substance.Under the condition of gasoline premix rate as high as 86%,the average indicated pressure and indicated thermal effi-ciency(ITE)during early injection(-160°CA ATDC)of diesel fuel reach 0.53 MPa and 49.41%respectively,and the emission levels of NOx,CO and total hydrocarbons(THC)are reduced,but the pressure rise rate exceeds the limit.By optimization of the gasoline injection strategy and use of the diesel multiple in-cylinder injections,the concentration and activity distribution of the mixture can be flexibly adjusted to delay the heat release process and reduce the pressure rise rate.Under the conditions of the first diesel early injection quantity of 1.9 mg/cyc and the secondary diesel direct injection of 1.0 mg/cyc,the indicated thermal efficiency is further increased to 49.55%.

关 键 词：双燃料发动机 汽油压燃 双、单歧管喷射策略 活性分层 

分 类 号：TK411[动力工程及工程热物理—动力机械及工程]