EXPERIMENTAL & THERMODYNAMIC ANALYSIS OF CI ENGINE USING DIESEL BASED BIOFUEL BLENDS

Abstract

The need for alternative and viable energy sources for the automotive industry is increasing due to the fast depletion of fossil fuel reserves. In the present scenario fluctuating petroleum prices, inconsistent supply, global politics, conflicts of oil producing countries sky-rocketing energy demands, lacking oil reserves make an energy intensive country like India, vulnerable to energy security. Rapid industrialization has significantly increased the world’s energy usage. It has been visualized that petroleum reserves will be scanty, and levels of pollution and global warming will be ample. One can solve these problems by using cleaner and renewable energy sources. For a few years, researchers across the world found Biodiesel as a favourable potential energy source to fulfil its energy needs due to its availability, renewable nature, low toxicity and lesser polluting nature. There are various sources of biofuel identified by the scientists and researchers so far, which include edible oil, non-edible oil, animal fats, microbial feedstocks, waste cooking oil, etc. making biodiesel viable for use and economical for production is the very next challenge for researchers. This doctoral thesis emphasizes on various selection criteria e.g. physicochemical properties, structural composition, environmental aspects, economic aspects etc. to choose better alternative out of the available biofuel resources. Biodiesel can be easily prepared by renewable feed stocks. It is biodegradable and non-toxic as well as it can be used in pure state or by blending with diesel in a diesel engine without any major engine modifications. In this study, biodiesel is produced from tallow oil and blended in different ratios (10%, 20% and 30% abbreviated as B10, B20 and B30 respectively) with diesel and used as an engine fuel to compare combustion and performance characteristics e.g. in-cylinder pressure, rate of pressure rise, mean gas temperature, heat release rate, brake power, specific fuel consumption, brake thermal efficiency and torque. The experimental results showed that engine performance parameters support the use of biodiesel and its blends as fuel as the difference between maximum brake power values of diesel and biodiesel blends (B30) is 1.7% which is un- vii noticeable, considering its other benefits. The similar results obtained for other characteristics. However, specific fuel consumption was higher in the case of biodiesel blends because of its lower heating value relative to diesel. Considering the fact that animal fat is voluminous by-product of meat Industry and it has limited use otherwise, the present investigation illustrates that biodiesel from animal fat can be used with efficacy without modifications in engine design. Biodiesel has been accepted as an alternate fuel to power engines. Biodiesel, prepared by transesterification of tallow as a feedstock, is used to fuel a compression ignition (CI) engine. An Exergy-energy analysis is compared with baseline diesel at various engine design variables. Brake-specific fuel consumption (BSFC), fuel energy, thermal efficiency, heat loss, energetic efficiencies, and exergy destruction through exhaust gases were determined for a single cylinder, direct injection, variable compression ratio (VCR) CI engine. Data analysis provides optimal operating conditions for the efficient combustion of B20 blend fuel. Optimal performance was obtained at a compression ratio of 17.5 and injection pressure of 210 bar, with energy efficiency observed as 31.69% and the maximum efficiency observed for diesel was 32.67%. Exergetic efficiency values were 24.97% and 26.37%, respectively. Based on the data, it is proposed that B20 tallow-based biodiesel can be used as an efficient and sustainable fuel.