International Journal of Innovative Technology and Exploring Engineering (IJITEE) ISSN: 2278-3075, Volume-3, Issue-2, July 2013 82 Computer Simulation of CI Engine for Diesel and Biodiesel Blends Laukik P. Raut Abstract-Among the alternative fuels, biodiesel and its blends are considered suitable and the most promising fuel for diesel engine. The properties of biodiesel are found similar to that of diesel. Many researchers have experimentally evaluated the performance characteristics of conventional diesel engines fuelled by biodiesel and its blends. However, experiments require enormous effort, money and time. Hence, a cycle simulation model incorporating a thermodynamic based single zone combustion model is developed to predict the performance of diesel engine. A comprehensive computer code using “C” language was developed for compression ignition (C.I) engine. Combustion characteristics such as cylinder pressure, heat release, heat transfer and performance characteristics such as work done, brake power and brake thermal efficiency (BTE) were analyzed. On the basis of first law of thermodynamics the properties at each degree crank angle was calculated. The simulated combustion and performance characteristics are found satisfactory with the experimental results. Keywords: - Biodiesel, Numerical modeling, simulation. I. INTRODUCTION Modeling compression ignition engine depends on characteristics of fuel. It is a process of designing a model of real system and conducting experiment with it for the purpose of understanding the behavior of the system. The Numerical Model of a diesel engine can be regarded as an explanation of real engine operation, which combines mathematical relation between the relative components, can be used to simulate the dynamic process of diesel engine. A clear overview of engine operation is helpful to understand the modeling of a real diesel engine. It serves as a tool for better understanding of combustion and its effect on engine, so as to build up more strong real systems. Computer simulation has contributed enormously towards new evaluation in the field of internal combustion engines. Mathematical tools have become very popular in recent years owing to the continuously increasing improvement in computational power. Diesel engines occupy a prominent role in the present transportation and power generation sectors. There have been many methods tried and are in use to reduce pollutant emissions from a diesel engine. The main options to reduce pollutants are the usage of bio-fuels and adopting some modifications to the combustion process. Diesel engine simulation models can be used to understand the combustion performance; these models can reduce the number of experiments. From the point of view of protecting the global environment and the concern for long-term supplies of conventional diesel fuel, it becomes necessary to develop alternative fuels that give engine performance at par with diesel. Among the alternative fuels, biodiesel holds good promises as an eco- friendly alternative fuel [1]. Manuscript received on July, 2013. Laukik P. Raut, Assistant Professor G. H. Raisoni College of Engineering Nagpur, India. Vegetable oil obtained from non edible sources are considered promising alternate fuel for compression ignition (CI) engine compared to their edible counterpart due to the food vs. fuel controversy. Engine performances using various sources of biodiesel viz., (a) salmon oil [2]; (b) rapeseed oil [3–5] ; (c) rubber seed oil [6]; (d) tobacco seed oil [7] ; (e) sunflower seed oil [8]; and; (f) soybean oil [9]; (g) jatropha curcus oil [10]; (h) karanja oil [11] were studied. As stated above, researchers have experimentally evaluated the performance characteristics of conventional diesel engines fuelled by biodiesel and its blends. However, experiments require enormous effort, money and time. A realistic numerical simulation model could reduce such effort. Numerical simulation based on mathematical modeling of diesel engine processes have long been used as an aid by design engineers to develop new design concepts. The present study describes a cycle simulation model. This thermodynamic based model follows the changing thermodynamic state of the working fluid through the engine intake, compression, combustion, expansion and exhaust processes for predicting the performance of a diesel engine fuelled by diesel and also the different blends of diesel and biodiesel. The model predicts the performance of a CI engine in terms of brake power and brake thermal efficiency for all the fuels considered for the present study. Fuel properties [11] and the engine design and operating parameters are specified as inputs to the model. The purpose of this project i.e. Numerical Modeling of CI Engine is to determine the effects of fuelling a diesel engine with diesel and bio-diesel fuel blends. The investigation has been done on 100% diesel fuel and 20% bio-diesel blend with diesel. The results are the compared with the results get from experimentations. Some specific objects are to evaluate the performance of, 1. Engine output. 2. Numerical Modeling results. 3. To predict the net heat release for B20. 4. To investigate the output parameters such as temperature, pressure, heat release etc. II. BIODIESEL CHARACTERISTICS 2.1 Transesterification of Vegetable Oil The vegetable oil is transesterified using methanol in the presence of sodium hydroxide (NaOH) as a catalyst (Figure 1 and 2). The parameter involved in the processing such as catalyst amount, molar ratio of alcohol to oil, reaction temperature and reaction time are optimized. Figure 1: - Transesterification chemistry of vegetable oil