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论文类型：期刊论文
发表时间：2015-04-01
发表刊物：INTERNATIONAL JOURNAL OF ENGINE RESEARCH
收录刊物：SCIE、EI、Scopus
卷号：16
期号：3,SI
页面范围：441-460
ISSN号：1468-0874
关键字：Reactivity-controlled compression ignition; cyclic variations; multi-dimensional simulation; octane number; cetane number; low-temperature combustion; methanol
摘要：Cyclic variations in dual-fuel reactivity-controlled compression ignition combustion were investigated using multidimensional simulations of a light-duty diesel engine. By comparing results with measured pressure traces from 300 consecutive cycles, it was found that the standard deviation of the 50% burn point in reactivity-controlled compression ignition combustion could be satisfactorily reproduced by monitoring the sensitivity of the 50% burn point to changes in initial in-cylinder temperature at intake valve closing in the simulations. Using this approach, the influences of fuel reactivity, diesel mass fraction, combustion mode, exhaust gas recirculation rate, intake pressure, and injection strategy on combustion stability were investigated. It was found that diesel/methanol reactivity-controlled compression ignition combustion exhibits larger cyclic variations than diesel/gasoline at the same operating conditions due to the lower reactivity of methanol. Compared to gasoline homogeneous charge compression ignition and diesel partially premixed combustion, diesel/gasoline reactivity-controlled compression ignition combustion showed the lowest cyclic variations for a given 50% burn point. When the 50% burn point was kept constant by adjusting the intake temperature, the introduction of exhaust gas recirculation and an increase in intake pressure resulted in decreased cyclic variations. Under the conditions tested in this study, with the employment of retarded injection timing, single injection, and increased injection pressure, the in-cylinder equivalence ratio becomes richer, which is helpful for the reduction in cyclic variations in reactivity-controlled compression ignition combustion. The overall results indicate that the present approach for describing cyclic variability is useful for practical applications.