Comparison of Diesel Engine Performance and Emissions from Neat and Transesterified Vegetable Oils

ABSTRACT A single-cylinder, 0.36 L, DI Diesel engine was operated on a certified No. 2. Diesel fuel, cottonseed oil, sunflowerseed oil, methyl ester of cottonseed oil, and methyl ester of sunflowerseed oil. The purpose of this study was to provide a comparison of performance and emission data when operating on neat vegetable oils, transesterified vegetable oils, and Diesel fuel. Results comparing the various vegetable oil fuels with No. 2 Diesel fuel generally show slight improvements in thermal efficiency and higher exhaust gas temperatures when operating on vegetable oils; equal or higher gas-phase emissions with vegetable oils; lower indicated specific revertant emissions with vegetable oils; and significantly higher aldehyde emissions, including an increased percentage of formaldehyde.