Comparative environmental behavior of bus engine operating on blends of diesel fuel with four straight vegetable oils of Greek origin: Sunflower, cottonseed, corn and olive

• Published in: Fuel (Guildford) 2011-11, Vol.90 (11), p.3439-3446
• Main Authors: Rakopoulos, D.C., Rakopoulos, C.D., Giakoumis, E.G., Dimaratos, A.M., Founti, M.A.
• Format: Article
• Language: English
• Subjects: Applied sciences; Blends; Bus diesel engine; Diesel fuel blends; Diesel fuels; Emissions; Energy; Energy. Thermal use of fuels; Engines; Engines and turbines; Equipments for energy generation and conversion: thermal, electrical, mechanical energy, etc; Exact sciences and technology; Fuels; Helianthus; Olea; Olives; Origins; Polymer blends; Straight vegetable oils; Sunflowers; Vegetable oils
• ISSN: 0016-2361; 1873-7153
• DOI: 10.1016/j.fuel.2011.06.009

► Study of environmental behavior of bus diesel engine with four vegetable oils. ► Comparison against the neat diesel fuel case. ► Reduction of smoke and slight increase of NOx with vegetable oil blends. ► Very slight increase of emitted CO and HC with vegetable oil blends. ► Effectively the same brake thermal efficiency with vegetable oil blends. An experimental study is conducted to evaluate the use of sunflower, cottonseed, corn and olive straight vegetable oils (SVO) of Greek origin, in blends with diesel fuel at proportions of 10vol.% and 20vol.%, in a fully instrumented, six-cylinder, turbocharged and after-cooled, heavy duty (HD), direct injection (DI), ‘Mercedes-Benz’, mini-bus engine installed at the authors’ laboratory. The series of tests are conducted using each of the above blends, with the engine working at two speeds and three loads. Fuel consumption, exhaust smokiness and exhaust regulated gas emissions such as nitrogen oxides (NOx), carbon monoxide (CO) and total unburned hydrocarbons (HC) are measured. With reference to the corresponding neat diesel fuel operation, the vegetable oil blends show reduction of emitted smoke with slight increase of NOx and effectively unaffected thermal efficiency. Theoretical aspects of diesel engine combustion, combined with the very widely differing physical and chemical properties of the vegetable oils against those for the diesel fuel, aid to the correct interpretation of the observed engine behavior.