Experimental Investigations to Improve the Performance of Rubber Seed Oil by Exhaust Gas Preheating

In the context of fossil fuel crisis and ever increasing vehicle population, the search for alternative fuel has become necessary. Vegetable oil can be used as an alternative fuel for the diesel engine operation. How ever, engine performance is inferior to diesel due to their higher viscosity. The higher viscosity of vegetable oil causes improper atomization of fuel during injection resulting in incomplete combustion. This leads to smoky exhaust in a diesel engine. While pre-heating of vegetable oil, it was found that viscosity reduces exponentially with temperature. The high temperature of the exhaust, which is otherwise wasted, can be used to preheat the vegetable oil. For this purpose a heat exchanger has to be designed. It was observed that the rubber seed oil (RSO) requires a heating temperature of 155°C to bring down its viscosity to that of diesel. The objective of this paper is to study the performance, combustion and emission characteristics of a single cylinder diesel engine using exhaust gas preheated rubber seed oil (155°C) and rubber seed oil (without preheating) and compare the results with that of base diesel fuel. The experimental results show that the brake thermal efficiency increases from 26.56% to 27.89% when the fuel is preheated to a temperature of 155°C. The CO and smoke emission of preheated RSO reduces by about 15% and 34% at 155°C compared with RSO (without preheating). It is also seen that the ignition delay and combustion duration decreases with preheated oil, which indicates faster heat release and leads to higher thermal efficiency.