The Effect of Butanol-Gasoline Blends on Harmful Engine Deposits

It is well known that alcohol based fuels may have been regarded as one of the alternative fuels because they have several physical and combustion properties similar to gasoline. Ethanol and butanol are alcohols considered as the most promising biocomponents for currently used conventional fuels. However, taking into account the numerous advantages of butanol over ethanol, and its properties, closer to those of gasoline, it is believed that it has greater application potential in the future environmentally-friendly fuels. For these reasons, butanol is under consideration to replace ethanol as an alternative fuel to gasoline especially as a gasoline blending bio-component. Therefore, this paper is focusing on the assessment of the influence of butanol addition to gasoline on harmful deposit formation in a various generation of spark ignition engine. Currently, only few research papers had discussed in very general this very important problem. Engine tests of various butanol blends with gasoline are described in order to determine the impact of butanol on the formation of deposits on the intake valves, in combustion chambers and on/in fuel injectors during the operation of a various type SI engines. Following the tests, comprehensive quantitative assessments of the deposits formed on the surfaces of the above-mentioned engine operating elements and the fuel injection system were made. Both “in-house” test procedure as well as Europe-wide procedures (developed by CEC) and specified in Worldwide Fuel Charter has been used in engine tests. A short comparative impact analysis of butanol and ethanol as a gasoline blending bio-components on engine deposit formation was also made.