Emissions From IC Engines Fueled With Alcohol–Gasoline Blends: A Literature Review

Since air pollution by automotive exhaust gases is of increasing concern around the world, an examination of the work that has been done with regard to evaluating and reducing it can help focus future efforts in dealing with it. Alcohol-containing fuels not only have been shown to have the potential to produce less of many of the polluting gases, but they also constitute a viable alternative to gasoline from the standpoint of efficiency and reducing dependence on the rapidly dwindling supply of petroleum fuel. This report provides a survey of the literature concerning research reported since 1975 on emissions from IC engines operating on alcohol-gasoline fuel blends. The effects of alcohol on the exhaust emissions (carbon monoxide (CO), hydrocarbons (HC), nitrogen oxides (NO_x), and the aldehydes (CHO)) are reviewed. A comparison is made of the emissions benefits achieved when methanol or ethanol is used either in neat form or as the blending agent with gasoline. The primary dependent variable considered is emission level (reported on various bases) with the main independent variables being fuel composition, equivalence ratio, and ignition timing. Brief mention is also made of the potential emissions reduction that may be achieved by using dissociated methanol.