Effect of fuel oxygen on the energetic and exergetic efficiency of a compression ignition engine fuelled separately with palm and karanja biodiesels Jibanananda Jena * , Rahul Dev Misra National Institute of Technology, Mechanical Engineering Department, Silchar, Assam 788010, India article info Article history: Received 25 September 2013 Received in revised form 18 February 2014 Accepted 20 February 2014 Available online xxx Keywords: Energy analysis Exergy analysis Efficiency Irreversibility Biodiesel fuel oxygen abstract Exergy analysis of any thermodynamic system can take care of the limitations of energy analysis such as irreversible losses, their magnitude and the source of thermodynamic inefficiencies apart from energy losses. In the present study, both the analyses along with heat release analysis are conducted on a natural aspirated diesel engine fuelled separately with palm biodiesel (PB), karanja biodiesel (KB), and petro- diesel (PD) using the experimental data. Since the engine performs best at about 85% loading condition, the energetic and exergetic performance parameters of the engine are evaluated at 85% loading condition for each type of fuel. The aim of the study is to determine the effect of fuel oxygen on energy and exergy efficiencies of a CI (compression ignition) engine. Various exergy losses, exergy destruction and their ratios associated with the heat transfer through cooling water, radiation, exhaust gas, friction, and some uncounted exergy destruction are investigated. Apart from exergy loss due to heat transfer; the un- counted exergy destruction (due to combustion) also plays a major role in the system inefficiency. Based on the comparative assessment of the obtained results, it is concluded that a better combustion with less irreversibility is possible with the increase in O 2 content in the fuel. Ó 2014 Elsevier Ltd. All rights reserved. 1. Introduction The compression ignition (CI) engine is the most preferred prime mover in many applications, owing to its reliability com- bined with excellent fuel efficiency. In general, CI engines are designed to run with petroleum fuel (fossil fuel). Combustion of fossil fuel is the major source of CO 2 and GHG S emissions to the atmosphere, which resulting severe environmental problem like Global warming and unnatural climate change. In this regard, biofuels may be considered as one of the alternative fuel options provide a partial solution to both these problems, by replacing fossil fuel use and thereby reducing CO 2 concentration and GHG emissions. The fuel properties of these biofuels are similar to pet- rodiesel in most ways and hence may be used with little or no engine modification. So exploitation of biofuel efficiently in the CI engine is highly required. In order to analyse engine performance and to evaluate quantitatively the inefficiencies associated with various processes; second law analysis is a better option. Second law analysis deals with the key word e ‘‘exergy” that explains the potential of the system to produce useful work. Unlike energy, exergy can be destroyed, which is a result of some phenomena such as combustion, friction, mixing, throttling etc [1]. The exergy destruction is a source for insufficient use from fuel exergy to produce useful mechanical work in an IC engine. The reduction of exergy destruction (irreversibility) can lead to better engine per- formance by more efficient exploitation of fuel [2]. Flynn et al. [3] explained a new observation in IC engine studies. They developed a computer model for second law analysis of a turbocharged diesel engine under transient condition. It was reported that combustion irreversibility was the important factor for system inefficiency and transient in-cylinder irreversibilities were different from steady- state. Alasfour [4] applied an energy and exergy analysis to an SI engine operating at steady-state, to evaluate the use of a butanole gasoline blend as fuel and found that energetic efficiency was about 28% of the fuel input energy. Canakci and Hosoz [5] presented a comparative study of energy and exergy analyses for a 4-cylinder turbocharged diesel engine fuelled with various biodiesels and petrodiesel. Caliskan et al. [6] applied exergy analysis to a John Deere 4045T diesel engine run with no. 2 diesel fuel, Soybean oil Methyl Easter and High-Oleic Soybean oil Methyl Easter at * Corresponding author. E-mail addresses: jivanjena@gmail.com (J. Jena), misrardnits@gmail.com (R. D. Misra). Contents lists available at ScienceDirect Energy journal homepage: www.elsevier.com/locate/energy http://dx.doi.org/10.1016/j.energy.2014.02.079 0360-5442/Ó 2014 Elsevier Ltd. All rights reserved. Energy xxx (2014) 1e9 Please cite this article in press as: Jena J, Misra RD, Effect of fuel oxygen on the energetic and exergetic efficiency of a compression ignition engine fuelled separately with palm and karanja biodiesels, Energy (2014), http://dx.doi.org/10.1016/j.energy.2014.02.079