Performance of a two-stroke outboard engine using Jatropha curcas L. biolubricants

Abstract

Two-stroke outboard engines for smaller boats are the most used in poor countries for low-scale fishing. The operation of these motors involves loss lubrication, that is, the lubricant is mixed with the fuel and the debris is expelled into the water through the exhaust. In order to contribute to the reduction of the contamination of the water bodies, the development and use of lubricants of natural origin has been visualized. In the present work, biolubricants were developed from the oil of the seed of Jatropha curcas L. (Eupohorbiaceae), by transesterification reactions with short chain alcohols and subsequent polymerization with ethylene glycol, the products, consisting of a mixture of alkyl esters and polyethylene glycol esters of fatty acids, were characterized physicochemically and their effect on the performance of a double cylinder engine of 8 H.P. was determined. The physical and chemical characteristics of the biolubricants are similar to other lubricants based on previously reported vegetable oils, although in viscosity they were below the corresponding standards. The biolubricant made with propyl alcohol allowed the engine to perform similarly to mineral oil, maintaining the pressure in the combustion chamber at levels statistically similar to mineral oil and higher than that obtained with the biolubricant made with butanol. The performance of the engine running on mineral lubricant was higher (t = 3.164, P=0.034) than when using the methyl biolubricant, while there were no differences when using the other biolubricants.