An experimental assessment of prospective oxygenated additives on the diverse characteristics of diesel engine powered with waste tamarind biodiesel V. Dhana Raju a, * , Harish Venu b , Lingesan Subramani c , P.S. Kishore d , P.L. Prasanna a , D. Vinay Kumar e a Department of Mechanical Engineering, Lakireddy Bali Reddy College of Engineering, Mylavaram, A.P, 521230, India b Department of Automobile Engineering, Vel Tech Rangarajan Dr.Sagunthala R&D Institute of Science &Technology, Avadi, 600062, Chennai, India c Department of Automobile Engineering, Madras Institute of Technology (MIT) Campus, Anna University, Chennai, 600044, India d Department of Mechanical Engineering, Andhra University College of Engineering (A), Andhra University, Visakhapatnam, 530003, A.P, India e Department of Mechanical Engineering, Vignan’s Foundation for Science Technology and Research, Guntur, 522213, Andhra Pradesh, India article info Article history: Received 1 March 2019 Received in revised form 22 March 2020 Accepted 7 May 2020 Available online 11 May 2020 Keywords: Biodiesel Combustion DIESEL-RK Exhaust emissions Oxygenated fuel additives Tamarind seed methyl ester abstract Rapid depletion of petroleum resources, surge in fuel prices and stringent emission norms play a key role on economic development of a country like India in terms of energy efficiency, which attracts the re- searchers to search for novel alternative fuel for diesel. The work reported here focuses on the effect of various oxygenated additives such as diethyl ether, dimethyl ether and dimethyl carbonate to 20% tamarind seed methyl ester (TSME 20) biodiesel blend of different concentrations (6% and 12%) on volume basis to examine engine characteristics. The test results revealed that 12% diethyl ether added TSME20 is shown considerable enhancement in brake thermal efficiency, which is 4.22% higher over tamarind biodiesel blend. Similarly, TSME20 DEE 12 has shown significant reductions in harmful engine tailpipe emissions such as carbon monoxide, hydrocarbon, oxides of nitrogen and smoke opacity which are noted to be about 10.68%, 33.33%,10.33% and 27.72% respectively when compared to diesel fuel at full load. Further, the DIESEL-RK theoretical simulation results are compared with the experimental values, conducted at the same operating conditions and it is inferred that 12% diethyl ether addition to TSME 20 has shown promising engine characteristics both experimentally and theoretically. © 2020 Elsevier Ltd. All rights reserved. 1. Introduction In lieu of rising depletion and in a way to find better alternative for liquid petroleum, various fuels have been introduced and used which are nevertheless new to the very first diesel engine designed and experimented by Rudolf diesel merely with Peanut biodiesel. Biodiesel, one among the diverse fuels, started becoming more and more popular day by day owing to its non-toxic nature and chances of fuel delivery from non-edible vegetables and plants which is environmentally benign. For the past decade, biodiesel has laid a solid foundation on transportation and industrial sector as it is a very viable option of cheap cost and abundant availability. With a specific goal to save petroleum products from constant utilization for different applications, biodiesel came into possible existence. Kader et al. [1] explored the extraction of biodiesel from the waste tamarind seeds through fixed bed fire-tube heating pyrolysis pro- cess and viability of tamarind seed biodiesel, as the feedstock were available in large quantity across the world for the production of biofuel and its applications in diesel engines. Praveen et al. [2] experimentally investigated the pyrolysis kinetic characteritsic studies for tamarind seed oil. The rate of oil yield for the tamarind biomass wastes can be modelled satisfactorily by a simplified equation, which was found to fit the experimental data fairly well. The results of this paper may be useful for rational design and operation of a pyrolysis system for potentially thermal conversion of biomass solid wastes into bio-fuels. Balaji et al. [3] reported similar research work of optimum extraction of oil yield from the tamarind seed through solvent extraction technique and the * Corresponding author. E-mail addresses: dhanaraju.v@lbrce.ac.in (V.D. Raju), harishvenuresearch@ gmail.com (H. Venu), s.lingesan@gmail.com (L. Subramani), psrinivaskishore@ gmail.com (P.S. Kishore), prasannapedarla19@gmail.com (P.L. Prasanna), vnykmr. d@gmail.com (D.V. Kumar). Contents lists available at ScienceDirect Energy journal homepage: www.elsevier.com/locate/energy https://doi.org/10.1016/j.energy.2020.117821 0360-5442/© 2020 Elsevier Ltd. All rights reserved. Energy 203 (2020) 117821