Rapeseed oil esters as diesel engine fuel

Esters of rapeseed oil with short chain aliphatic alcohols (methyl and ethyl alcohols) were prepared using an alkaline catalyst (KOH) and an acidic catalyst (H2SO4). The volumetric ratio of the alcohol-to-oil was 2: 1, and the catalyst concentration was 5% based on the mixture weight. The esterification rate was found to be faster using acidic catalyst. The esterified products were tested for their fuel properties and compared to those of standard diesel fuel. The calorific value, flash point, viscosity, and pour point were among these properties. The results have shown that these esters are advantageous over diesel fuel as they are free from sulfur. Thus the combustion of the oil esters in the engine will not produce acidic sulfur oxides. Moreover, they are also free from nonburnable materials whose deposition may cause abrasion of engine parts. Other fuel properties are more or less similar to those of standard fuel. This means less corrosion of engine parts as well as less pollution of the environment. The performance of a 4 cylinder compression ignition engine (CIE) when fuelled with the prepared esters was compared to that when fuelled with standard diesel fuel. The results show that the brake specific fuel consumption was lower and the thermal efficiency was higher using rapeseed oil esters.