RESEARCH ARTICLE Experimental study of methyl tert-butyl ether as an oxygenated additive in diesel and Calophyllum inophyllum methyl ester blended fuel in CI engine Ashok Bragadeshwaran 1 & Nanthagopal Kasianantham 1 & Saravanan Ballusamy 2 & Kavalipurapu Raghu Tarun 1 & Arumuga Perumal Dharmaraj 3 & Muhammad Usman Kaisan 4 Received: 24 April 2018 /Accepted: 24 September 2018 # Springer-Verlag GmbH Germany, part of Springer Nature 2018 Abstract This work presents the effect of the ternary oxygenated additive on diesel biodiesel blended fuel to evaluate the engine charac- teristics. The Calophyllum inophyllum trees being abundant in India can lessen the dependence on petroleum imports to a specific extent. Methyl tertiary butyl ether is used as an oxygenated additive for the ternary blends preparation as 5–20% by volume. Seven blends of neat baseline diesel, biodiesel (Calophyllum inophyllum Methyl Ester), a blend of diesel (50%)-biodiesel (50%), a blend of diesel (50%)-biodiesel-methyl tert-butyl ether (5, 10, 15, and 20%) are prepared which are tested on a single cylinder, constant speed diesel engine. The experimental results were revealed that the replacement of biodiesel by MTBE has shown a slight reduction in brake thermal efficiency with a slight increase in brake-specific fuel consumption. Further, the MTBE addition in ternary blends reduced the unburned hydrocarbon, CO, and NO x by 63.9, 6.4, and 3.37% respectively. In addition, the carbon dioxide emission is almost similar to diesel fuel at a higher addition of MTBE with diesel-biodiesel blend. In the combustion point of view, the addition of 5% MTBE resulted in 3.49 and 5.1% reduction of peak pressure and heat release rate are observed as compared to diesel fuel. Critical analysis in combustion aspects is also carried out and it is witnessed with prolonged ignition delay during MTBE addition with diesel-biodiesel blends. Keywords Biodiesel . Calophyllum inophyllum methyl ester (CIME) . Methyl tert-butyl ether (MTBE) . Transesterification Ternary blend . Oxygenated additive Abbreviations CI Compression ignition CIME Calophyllum inophyllum methyl ester DEE Diethyl ether MTBE Methyl tertiary-butyl ether CO Carbon monoxide CO 2 Carbon dioxide BTE Brake thermal efficiency BSFC Brake-specific fuel consumption BSEC Brake-specific energy consumption B100 100% Biodiesel (Calophyllum inophyllum) D50B50 50% diesel + 50% biodiesel D50B45DEE5 50% diesel + 45% biodiesel + 5% diethyl ether D50B40DEE10 50% diesel + 40% biodiesel + 10% diethyl ether D50B45MTBE5 50% diesel + 45% biodiesel + 5% methyl tertiary-butyl ether D50B40MTBE10 50% diesel + 40% biodiesel + 10% methyl tertiary-butyl ether HC Hydrocarbons NO x Oxides of nitrogen ppm Parts per million Responsible editor: Philippe Garrigues * Nanthagopal Kasianantham nanthagopalk@yahoo.com 1 School of Mechanical Engineering, VIT University, Vellore 632014, India 2 Department of Mechanical and Aerospace Engineering, Indian Institute of Technology (IIT), Hyderabad, India 3 Department of Mechanical Engineering, National Institute of Technology (NIT), Surathkal, India 4 Department of Mechanical Engineering, Ahmadu Bello University, Zaria, Nigeria Environmental Science and Pollution Research https://doi.org/10.1007/s11356-018-3318-y