Gasoline Simulated Distillation Profiles of U.S. Market Gasoline and Impacts on Vehicle Particulate Emissions 2023-01-1632

A gasoline’s distillation profile is directly related to its hydrocarbon composition and the volatility (boiling points) of those hydrocarbons. Generally, the volatility profiles of U.S. market fuels are characterized using a very simple, low theoretical plate distillation separation, detailed in the ASTM D86 test method. Because of the physical chemistry properties of some compounds in gasoline, this simple still or retort distillation has some limitations: separating azeotropes, isomers, and heavier hydrocarbons. Chemists generally rely on chromatographic separations when more detailed and precise results are needed.

High-boiling aromatic compounds are the primary source of particulate emissions from spark ignited (SI), internal combustion engines (ICE), hence a detailed understanding and high-resolution separation of these heavy compounds is needed. This paper presents analysis of 159 U.S. market gasoline samples using D86 distillation and ASTM D6730 detailed hydrocarbon analysis (DHA). The samples ranged in Particulate Matter Index (PMI) from 0.925 to 2.540 or Particulate Evaluation Index (PEI) of 0.584 to 2.715. Additional analysis was performed on 80 of the samples using ASTM D7096, a chromatographic method, to generate higher resolution simulated distillation (SimDis) profiles. SimDis cutpoints (%-off values) in the range of T95 to T98 show good correlation to PMI and PEI, demonstrating that SimDis analysis can provide a useful assessment of the PM-formation tendency of market gasolines.