Investigation of the Effect of Mid- And High-Level Ethanol Blends on the Particulate and the Mobile Source Air Toxic Emissions from a Gasoline Direct Injection Flex Fuel Vehicle

Abstract

This study examined the influence of low-, mid-, and high-ethanol fueling, as well as the influence of the aromatic hydrocarbons in the fuel blend, on the regulated and greenhouse gas emissions, the mobile source air toxic pollutants, and the particulate emissions from a current model flexible fuel vehicle equipped with a gasoline direct injection engine. This study utilized a total of four fuels, including a baseline U.S. EPA Tier 3 E10 fuel, one E10 fuel with higher aromatics content than the baseline E10, an E30 fuel that was splash-blended with the Tier 3 E10, and an E78 fuel. Testing was conducted over triplicate cold-start and hot-start LA92 cycles. The findings of this study showed that the higher ethanol blends, namely, the E30 and E78, led to statistically significant reductions of 9%–13% for total hydrocarbon (THC), 13%–44% for non-methane hydrocarbon (NMHC), 20%–35% for carbon monoxide (CO), and 17%–36% for nitrogen oxides (NOx) emissions compared to the high-aromatics E10 fuel. The emissions o...