Effect of Injection Pressure on Emission Performance of Bio-diesel and its Blends

Abstract

Non-edible vegetable oils can be used as an alternative fuel for diesel engine operation. The primary problems associated with using straight vegetable oils (SVO) as a fuel in a compression ignition internal combustion engines are caused by high fuel viscosity and low volatility. The high viscosity of vegetable oils can be reduced by using transesterification process of non-edible oil with an alcohol which provides a clean burning fuel (commonly known as bio-diesel) having low viscosity and it can be directly used in conventional unmodified diesel engine. Pongamia oil, a non-edible type is used in this investigation for studying its suitability for use in diesel engine. This paper deals with the results of investigations carried out in studying the fuel properties of pongamia oil (honge oil), pongamia methyl ester and its blends with diesel fuel from 10 to 50% by volume and running in a single cylinder four-stroke diesel engine with these fuels at different injection pressures. Various properties of the pongamia oil, pongamia methyl ester and its blends are evaluated using ASTM standards and compared in relation to that of conventional diesel fuel. The characterization of pongamia oil and its methyl ester have been carried out through Nuclear Magnetic Resonance (NMR) spectral analysis. Engine tests have been carried out with the aim of obtaining comparative measures of torque, power, specific fuel consumption, brake thermal efficiency, emissions and compute the behavior of the diesel engine running on pongamia methyl ester and its blends with diesel. Biodiesel substantially reduces smoke opacity, carbon monoxide and unburnt hydrocarbons in exhaust gases. The 20% pongamia methyl ester blend with diesel fuel gives better performance and performance of the engine has been improved at 20 MPa injection pressure. � 2005 The Automotive Research Association of India, Pune, India.