Exhaust Gas Emissions of Butanol, Ethanol, and Methanol-Gasoline Blends

Abstract

Emissions levels for CO, NOx , and unburned fuel (UBF) from a stationary four-cylinder Chrysler engine were measured under a variety of operating conditions for gasoline and three different 20 vol percent alcohol-gasoline blends. In tests of separate isobutanol, ethanol, and methanol blends, lower CO and NOx emissions were observed for the alcohol blends relative to gasoline, particularly for fuel-rich operation. Generally, on a volume (mole) basis unburned fuel emissions were highest for methanol blends and lowest for gasoline, but on a mass or OMHCE basis only small differences were noted. For a given fuel, the separate effects of engine speed, load, and equivalence ratio were examined.