Biodiesel development and characterization for use as a fuel in compression ignition engines

Neat vegetable oils pose some problems wizen subjected to prolonged usage in CI engine. These problems are attributed to high viscosity, low volatility and polyunsaturated character of the neat vegetable oils. These problems are reduced to minimum by subjecting the vegetable oils to the process of transesterification. Various properties of the biodiesel thus developed are evaluated and compared in relation to that of conventional diesel oil. These tests for biodiesel and diesel oil include density, viscosity, flash point, aniline point/cetane number, calorific value, etc. The prepared biodiesel was then subjected to performance and emission tests in order to evaluate its actual performance, when used as a diesel engine fuel. The data generated for various concentrations of biodiesel blends were compared with base line data generated for neat diesel oil. It was found that 20 percent blend of biodiesel gave the best performance amongst all blends. It gave net advantage of 2.5 percent in peak thermal efficiency and there was substantial reduction in smoke opacity values. This blend was chosen for long term endurance test. The engine operating on optimum biodiesel blend showed substantially improved behaviour. A series of engine rests provided adequate and relevant information that the biodiesel can be used ns an alternative, environment friendly fuel in existing diesel engines without substantial hardware modification.