title: Optimization of gasoline hydrocarbon compositions for reducing exhaust emissions.
abstract: Effects of hydrocarbon compositions on raw exhaust emissions and combustion processes were studied on an engine test bench. The optimization of gasoline hydrocarbon composition was discussed. As olefins content increased from 10.0% to 25.0% in volume, the combustion duration was shortened by about 2 degree crank angle (degrees CA), and the engine-out THC emission was reduced by about 15%. On the other hand, as aromatics content changed from 35.0% to 45.0%, the engine-out NOx emissions increased by 4%. An increment in olefins content resulted in a slight increase in engine-out CO emission, while the aromatics content had little effect on engine-out total hydrocarbon (THC) and CO emissions. Over the new European driving cycle (NEDC), the THC, NOx and CO emissions of fuel with 25.0% olefins and 35.0% aromatics were about 45%, 21% and 19% lower than those of fuel with 10.0% olefins and 40.0% aromatics, respectively. The optimized gasoline compositions for new engines and new vehicles have low aromatics and high olefins contents.
authors.affiliation: State Key Laboratory of Automotive Safety and Energy, Tsinghua University, Beijing 100084, China. shenyt03@mails.tsinghua.edu.cn
authors.forename: Yitao
authors.initials: Y
authors.lastname: Shen
authors.forename: Shijin
authors.initials: S
authors.lastname: Shuai
authors.forename: Jianxin
authors.initials: J
authors.lastname: Wang
authors.forename: Jianhua
authors.initials: J
authors.lastname: Xiao
mesh_terms: D000475:Alkenes / Q000032:analysis; D004784:Environmental Monitoring / Q000295:instrumentation / Q000379:methods; D005742:Gasoline / Q000032:analysis*; D006838:Hydrocarbons / Q000032:analysis*; D006841:Hydrocarbons, Aromatic / Q000032:analysis; D001335:Vehicle Emissions / Q000517:prevention & control*
chemical_list: D000475:Alkenes; D005742:Gasoline; D006838:Hydrocarbons; D006841:Hydrocarbons, Aromatic; D001335:Vehicle Emissions