Evaluating waste vegetable oils as a diesel fuel

Abstract

The research into turning a vegetable oil into an alternative fuel has been underway for some time [1-5]. Although some countries have begun to use some biomass as a fuel for the automobile, the wide use of an alternative fuel has been difficult without substantial subsidies owing to the cost of the biomass which is 3-5 times higher than that of fossil fuel. However, the cost of waste vegetable oil is competitive with that of fossil fuel and, in the collection of waste vegetable oil, there is an additional advantage of being able to prevent its illegal dumping. Furthermore, the reuse of the oil will improve the profitability of its collection. This research focused on the engine performance and emission characteristics of methyl-esterified vegetable oil when it is used in a diesel engine of an automobile. The research conducted with direct injection (DI) and indirect injection (IDI) diesel engines revealed that, for engine performance, the alternative fuel was on a par with light oil. For the emission of particulates, with the IDI diesel engine there was no significant difference between the light oil; however, the DI engine proved to emit a much larger quantity of particulates in the low to middle load range. The research also revealed the necessity for countermeasures against solidification of the fuel during the winter months, the generation and emission of aldehyde and benzene, which are typical of oxygenated fuel, and the tempuralike smell caused by propionaldehyde.