Effects of Ethanol and/or Methanol in Alcohol-Gasoline Blends on Exhaust Emissions

Abstract

The effect on exhaust gas emissions (carbon monoxide, CO, hydrocarbons, HC, and aldehydes, CHO) resulting from mixing methanol and/or ethanol with gasoline for automotive fuels has been studied experimentally. Tests were conducted on an OEM four-cylinder engine running at different conditions of equivalence ratio and spark timing. Fuel blends with different percentages of alcohol content and different ratios of methanol to ethanol in the alcohol mixture were tested. Results of this investigation indicated that the presence of either or both of the alcohols in fuel blends significantly reduced the concentration of carbon monoxide in the exhaust emissions (up to 40–50 percent compared to pure gasoline only), with methanol slightly more effective than ethanol. Hydrocarbon emissions were also decreased by increasing the alcohol content of the fuel, with minimum hydrocarbon production occurring at percent alcohol-gasoline blends in conjunction with near-stoichiometric air-fuel ratios. However, aldehyde emissions were found to be markedly higher with alcohol-gasoline blends. The 10 percent alcohol-gasoline blends were found to produce about 50 percent more aldehyde emissions than pure gasoline.

Experimental Investigation on Varying the Compression Ratio of Si Engine Working Under Different Ethanol-Gasoline Fuel Blends

“…However, the same figure shows that increasing the ethanol percentage above 10% results in a decrease of the maximum pressure to a value even lower than that of pure unleaded gasoline. This may be explained as follows: the addition of ethanol to gasoline has two effects on the fuel blend properties; the first is an increase of the Octane number (see Table 1) since the latent heat of evaporation of ethanol is much greater than that of gasoline and, accordingly, ethanol addition helps to delay the chain reactions of the end gas (Bata and Roan, 1989); the second is a decrease in the heating value. It is to be noticed that these effects have opposite results in terms of engine performance.…”

Performance and Emission Characteristics of Spark Ignition Engine Fuelled with Ethanol and Methanol Gasoline Blended Fuels

“…Palmer (1986) showed that 10% of ethanol addition to gasoline could reduce the concentration of CO emission up to 30%. Bata et al (1989) had tested different blend rates of ethanol gasoline fuels in engines, and found that the ethanol could reduce the CO and UHC emissions. Taylor et al (1996) used four alcohol fuels to blend with gasoline and concluded that adding ethanol can reduce CO, HC and NO emissions.…”

Unregulated emissions from a gasohol (E5, E15, M5, and M15) fuelled spark ignition engine

“…Lower boiling point of alcohols also helps in attaining greater degree of combustion [11]. Some experimental studies measured the gasoline engine emissions fuelled with gasohols [6,9,10,12]. These studies however do not cover the measurement of unregulated emissions from these fuels.…”