Effect of Refining Process in Biodiesel Fuel Production on Fuel Properties, Diesel Engine Performance and Emissions

This paper describes two topics. One is a study of the effects of refining process of biodiesel fuel on fuel properties, diesel engine performance and exhaust emissions. The second topic is a study to clarify the influences of plant oil sources for biodiesel production on combustion and emission characteristics. Plant oils or used cooking oils are reacted with methanol and a lye catalyst: KOH, to produce fatty acid methyl ester: unwashed-biodiesel. Washing the unwashed-biodiesel by water and dying processes are necessary in order to improve its fuel properties. Experiments were carried out on a single-cylinder, 4-stroke-cycle, DI diesel engine and various unwashed-, washed- and refined-biodiesel fuels derived from new or used cooking oil. From the result, it was found that the unwashed-biodiesel occurred unstable engine operation. And there was few difference in engine performance and emissions between biodiesel fuel from new and used cooking oil at same plant oil source.