Low Cost Modification Kit for Retrofitting on Small Diesel Engines to Run on Straight Vegetable Oils

Abstract

Many varieties of vegetable oils do have characteristics similar to that of diesel derived from petroleum crude and can be used directly as fuel in diesel engines. But varieties of problems are encountered on prolonged use of vegetable oils in the existing design of engines. The problems encountered in the existing design of the engine while working with vegetable oil are mainly greater load on the fuel pump and injector due to higher viscosity; filter clogging and difficult filtration; difficult cold starting due to residual oil in the combustion chamber; and vegetable oil's reaction with fuel line material. To address these problems and for reducing the viscosity of vegetable oils, different strategies suggested are: Pyrolysis; Dilution; Microemulsion; and, Transesterification. Out of these, transesterification is mostly adopted as it gives the matching properties with that of diesel and hence can be used without many modifications in the existing engine (1). But, the chemistry of transesterification requires careful and precise working which is normally not possible at local level at user end and hence commercial and logistic loading of prices leaves the same unfeasible. With the major research effort dedicated to the area of biodiesel, a small number of researchers are advocating the extension of Rudolph Diesel's concept of neat vegetable oil as CI engine fuel. Schrimpff (2) compared straight vegetable oil (SVO) with Bio-diesel (BD) on the issues of production,