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COMPARATIVE STUDIES ON MEDIUM GRADE LOW HEAT REJECTION DIESEL ENGINE AND CONVENTIONAL DIESEL ENGINE WITH CRUDE COTTON SEED OIL

D. Srikanth, M.V.S. Murali Krishna, P.Ushasri and P.V. Krishna Murthy

It has been found that the vegetable oils are promising substitute, because of their properties are similar to those of diesel fuel and they are renewable and can be easily produced. However, drawbacks associated with crude vegetable oils are high viscosity, low volatility call for low heat rejection diesel engine. Comparative studies were made on performance evaluation of medium grade LHR diesel engine (with air gap insulated piston with superni ( an alloy of nickel) crown and air gap insulated liner with superni insert) and conventional diesel engine (CE) with different operating conditions [normal temperature and pre-heated temperature] of crude cotton seed oil with varied injector opening pressure and injection timing. Performance parameters [brake thermal efficiency, brake exhaust gas temperature, volumetric efficiency, sound levels and coolant load], exhaust emissions [smoke levels and oxides of nitrogen] were determined at various values of brake mean effective pressure of the engine. Combustion characteristics (peak pressure, maximum rate of pressure rise and time of occurrence of peak pressure) were evaluated at peak load operation of the engine. Conventional engine showed deteriorated performance, while LHR engine showed improved performance with cotton seed oil at recommended injection timing and pressure in comparison with pure diesel operation on CE. The optimum injection timing was 32obTDC with conventional engine, while it was 30obTDC for LHR engine with cotton seed oil operation