Investigation of Best Performing Biofuel Among Various Bio Oils Diesel Engine Harishchandra V Astagi Department of Mechanical Engineering, PDA College of Engineering, Gulbarga, Karnataka, India Dr. Prashant Kamble Professor, Department of Ind. & Production Engineering, PDA College of Engineering, Gulbarga, Karnataka, India Abstract— The various available non-edible vegetable oils have been investigated experimentally for engine characteristics on a diesel engine. The non-edible straight vegetable oils used are Mahua, Neem, Castor and Linseed oil. These oils posed operational and durability problems with the long term usage. Poly-unsaturated character of straight vegetable oils, low volatility and, high viscosity are the main cause for poor performance. Hence, fuel pre-heating is done to reduce the viscosity of neat oils and experiment is carried out on single cylinder diesel engine. The various performance and emission parameters are investigated and compared with the baseline data of diesel. The experimental results showed the significant improvements found with use of neem oil and castor oil for performance and exhaust emissions characteristics of the engine. Keywords — Engine, Non-edible vegitable oils, Performance characteristics, Exhaust Emission Characteristics I. INTRODUCTION The limited resources of petroleum fuels and its products need for increasing concerns for environment, and steep rise in crude oil prices there has been renewed focus on vegetable oils as an alternative to petroleum fuels. Vegetable oil is environment friendly, renewable fuel and is easily available worldwide. These are the triggering factors to consider vegetable oils and their derivatives as substitute fuel to petroleum diesel. However, high viscosity and low volatility which are major disadvantages of vegetable oil cause poor fuel atomization, poor combustion, ring sticking, injector cocking, injector deposits, and lubricating oil dilution. The modern fuel injection system of engines is more sensitive to fuel viscosity. Viscosity of the vegetable oils needs to be reduced in order to improve fuel flow, combustion and engine performance. Heating is one of the methods adopted to reduce viscosity of vegetable oils. However transesterification and Blending with diesel are common methods used. Though many researchers worked on the various bio oils and investigated that vegetable oils are feasible substitutes for diesel fuel, but still a lot of work that needs to be carried to use vegetable oil in diesel engine. The literature review shows that many researchers have investigated non-edible vegetable oils such as Jatropha, kusum (Schlerlchera trijuga), Karanja (Pongamia glabra), Rice bran, linseed etc. and also some of the edible vegetable oils for the performance, combustion and emission characteristics of diesel engine. The present energy crisis inspired the authors to compare the engine characteristics of diesel engine using some of the non-edible oils such as Neem, Linseed, Mahua and Castor oil and select the best performing oil to be used as alternate fuel for diesel engine. II. CHEMICAL COMPOSITION Compared to conventional diesel, Vegetable oils have very low heat content, comparable cetane number, low volatality, and stoichiometric air/fuel ratio. Calorific value decreases with increasing un-saturation as a result of fewer hydrogen atoms in their molecular structure. The typical vegetable oil has following molecule structure: The molecule of vegetable oil contains R1, R2 and R3 straight chain alkyl groups and free fatty acids. The vegetable oil poses high viscosity and low volatility compared to mineral diesel. Two types of problems are associated with the use of vegetable oils in the engines - operational and durability problems. Operational problems are related to starting ability, ignition, combustion and performance. Durability problems are related to deposit formation, carbonization of injector tip, ring sticking and lubricating oil dilution. The extremely low volatility, high viscosity, polyunsaturated character of vegetable oils is the cause for the operational and durability problems. High viscosity of oils results in poor fuel atomization, large droplet size and thus high spray jet penetration. The jet tends to emerge in the form of solid stream instead of small droplets. This results in poor premixing and distribution with air in combustion chamber which lead to poor combustion, loss of power and economy. Blending with diesel, cracking / pyrolysis of oil, emulsification or transesterification of vegetable oils may overcome these problems. III. MATERIALS AND METHODS The Mahua, Neem, Castor and Linseed oil used for this work were collected, crushed in mechanical expeller from the seeds collected from Biofuel centre, Gulbarga University, Kalaburagi (Karnataka). International Journal of Engineering Research & Technology (IJERT) ISSN: 2278-0181 http://www.ijert.org IJERTV8IS040198 (This work is licensed under a Creative Commons Attribution 4.0 International License.) Published by : www.ijert.org Vol. 8 Issue 04, April-2019 189