Study of Gasoline Particulate Matter Index with Refinery Blends

Gasoline direct injection (GDI) engines can help meet future fuel economy standards but will also make future proposed particulate matter (PM) emissions targets challenging to meet. This is mainly due to the fundamental change in the combustion process in GDI engines compared to conventional port fuel injection (PFI) engines. Auto manufacturers have linked PM emissions to gasoline formulations. Researchers at the Honda Motor Company proposed the particulate matter index (PMI) as a measure for gasoline sooting tendency. In this paper, 59 gasoline blend stocks from seven refineries were collected in order to study the compositional effect of real refinery streams on gasoline PMI. 580 gasoline blends were made from the 59 blend stocks. No traditional metrics of fuel quality were found to correlate well with the PMI. Reformate and FCC Naphtha contribute most significantly to the PMI of gasoline. Based on the refinery modeling assumptions presented in this paper, it is shown that a decrease in PMI from 1.5 to 1.35 shrinks the gasoline pool by 10%; a decrease in PMI from 1.5 to 1.0 yields a reduction of 30%. Since reformate is the primary incremental octane supply in a refinery, increasing the base octane from 87 [R + M]/2 E10 to 95 RON E10 results in a 10% increase in PMI, while an increase from 87 [R + M]/2 E10 to 98 RON E10 results in a 30% increase.