摘要
均质压燃(HCCI)着火受控于化学反应动力学,缺乏直接调控手段,是HCCI研究核心之一.废气重压策略是实现汽油机HCCI的一种有效手段,废气除了加热、稀释等作用,其中存留的不完全氧化产物影响着火前化学反应动力学过程,改变HCCI着火时刻.为研究缸内实际残留不完全氧化产物对HCCI着火的影响规律和机制,根据缸内气体取样分析结果,利用汽油替代燃料详细氧化机理开展化学反应动力学仿真分析.结果表明:醛类、醇类和炔烃有较强的促进HCCI着火能力,甲烷则表现一定的抑制作用;考虑实际缸内各物质摩尔分数,在所研究工况下,CH2O、C2H2和C2H4对促进着火贡献最大,各不完全氧化产物对HCCI着火的协同影响近似等于各物质单独影响的简单叠加.
Homogeneous charge compression ignition(HCCI)auto-ignition is controlled by chemical kinetics,thus ignition timing control is one of the difficult obstacles for practical use of HCCI combustion and has been studied extensively. Retaining the burnt gases is an effective method for achieving gasoline HCCI. Besides heating and dilution effects of residual gas,some incomplete oxidation products in residual gases affect the HCCI auto-ignition via chemical kinetics. The objective of this study is to give an insight into the influence and influencing mechanism of these incomplete oxidation products on HCCI autoignition. On the base of in-cylinder sampling,simulation is carried out with detailed chemical kinetic mechanism of gasoline surrogate. Results show that aldehydes,alcohols and alkynes have significant effect on advancing HCCI auto-ignition,while CH4 shows inhibiting effect on it. Under engine operating conditions in this study,CH2 O,C2H2 and C2H4 contribute mostly in advancing HCCI auto-ignition among all incomplete oxidation products in-cylinder. And the combined effect of them on auto-ignition approximately equal to the sum of the effect of each species simply.
出处
《内燃机学报》
EI
CAS
CSCD
北大核心
2014年第5期414-419,共6页
Transactions of Csice
基金
国家自然科学基金资助项目(51206118)
关键词
汽油机
均质压燃
残余废气
着火时刻
gasoline engine
homogeneous charge compression ignition
residual gas
ignition timing
