Rapid growth of automobile industry has become a major reason for energy
consumption and environmental pollution around a large city seriously.
Saving energy greatly effects on the countries that do not have energy sources, so saving energy and varying energy source are demanded.
As the one of the measures for saving energy of varying energy source, the technology using alternative fuel has been developed.
There are some alternative fuels such as ethanol, methanol, natural gas, electricity, hydrogen, alcohol which can be substitute for gasoline or diesel fuel.
Ethanol is interesting as a fuel of automobile, because it is able to be used without retrofitting conventional gasoline engines. Therefore, ethanol must be considered as a fuel of automobile by the countries not having sufficient fuel source.
Methyl Tertiary Butyl Ether (MTBE) used for increasing Octane nmber of gasoline and increasing oxygen content becomes a current issue.
Nevertheless, MTBE has a big problem for causing to another environmental pollution widely. Therefore, an alcohol fuel is expected as a substitute fuel for MTBE.
In this study, the effect of ethanol mixing rate on exhaust emissions, fuel consumption rate and engine torque is tested in a gasoline engine without any retrofit. mixing rate is varied from 0% to 85% and engine speed and torque are also varied.
The result show ethanol mixing rate of 10 to 15% is considered as a suitable range in order to use the fuel without any retrofit. Maximum torque is decreased with mixing rate increase, but the torque shows similar value is the range of 10 to 15%. The values of CO, HC emission and fuel consumption are similar or slightly increased except the range of 10 to 15%.