Performance and Emission Analysis of CI Engine Fuel with Pre Heated Vegetable Oil

Abstract

Day by day increasing demand of petrol, depleting reserves of oil, concerns about environmental and governmental policies, increasing fuel rate has make it essential to search for alternate fuel and engine technologies which can be proved a good substitute and more environmental friendly. The present study is carried out on an unmodified single cylinder, constant speed, four stroke, air cooled, direct injection compressed ignition engine developing a power output of nearly 5.4 kW at 1500 rev/min which is generally used in agriculture sector. The said engine was operated using unheated and preheated Karanja oil, Jatropha oil and Diesel. Performance analysis, emission analysis with five gas analyser and vibration analysis with the help of FFT-analyser and accelerometer were carried out. The main problems associated with neat vegetable oils are their high viscosity and low volatility. Shell and tube type heat exchanger is used to exchange heat between exhaust gases and vegetable oils. It is possible to achieve higher temperature (more than 170°C) of vegetable oil using heat of exhaust gases. Preheating of Karanja oil and Jatropha oil to 100°C and 130°C their viscosity reduces to ASTM limits and similar to that of Diesel respectively. Density of Jatropha and Karanja vegetable oils is also decreases with increase in temperature. The calorific value of Karanja oil and Jatropha oil is 11% and 13% lower than Diesel fuel. It is possible to operate Diesel engine using preheated Karanja oil and Jatropha oil but with compromising certain performance parameters. BSFC and BSEC of both vegetable oil with different temperature is found higher than Diesel however preheat Karana oil to 80°C have similar BSFC and BSEC to that of Diesel at part load. Exhaust gas temperature of unheated vegetable oils was noted highest and ηbth of both vegetable oils with different temperature conditions found less than Diesel however preheat Karana oil to 80°C have ηbth similar to Diesel at part load. Nitrogen oxide emission with Karanja at all fuel inlet temperature and with unheated Jatropha were lower than Diesel but found higher with preheated Jatropha (130°C). Both vegetable oils with all inlet temperature conditions exhibits higher carbon dioxide emissions. Hydrocarbon emission with preheated Karanja (130°C) and Jatropha (130°C) were less than Diesel. CO emission reduces with increase in fuel inlet temperature but higher than Diesel up to 60% load. Measured vibrations on engine cylinder gave maximum values in a direction perpendicular to crankshaft in horizontal plane i.e. in direction of piston slap whereas on engine foundation vibrations are significantly more in vertical directions. The magnitude of vibration acceleration with Diesel was found significantly more with both preheated vegetable oils however preheated Karanja oil (130°C) shown least value.