DOI: 10.1002/ente.201300130 Technical Aspects of Ethyl Tert-Butyl Ether (ETBE) for Large-Scale Use as Gasoline Improver M. E. Bardin, [a] A. M. T. A. El-Dein Hussin, [b] P. A. Gushchin, [a] V. A. Vinokurov, [a] and A. A. Burluka* [c] Introduction The current concerns about sustainability of fossil fuels, in addition to the legislation aimed at reducing greenhouse gas emissions, have forced the automotive industry to search for renewable fuels with smaller carbon footprints to replace (either completely or partially) the conventional fuels. Alco- hols, particularly bioethanol and biomethanol and their ethers, ethyl tert-butyl ether (ETBE) and methyl tert-butyl ether (MTBE), are the most attractive renewable fuels for engines because of their compatibility with the existing fuel- ing distribution infrastructure and their potential to reduce engine emissions. [1–5] Furthermore, alcohols and ethers pos- sess a resistance to engine knocking greater than standard gasoline owing to their high octane numbers. Nonetheless, there is a huge variation in the potential for gasoline dis- placement by these different oxygenated compounds; this variation does not come solely from economical and legisla- tive factors but also from technical ones, and the present work aims to demonstrate that the use of ETBE has a number of advantages over other gasoline additives for large-scale deployment, even though the current economic data may not be advantageous. ETBE as fuel additive ETBE, as a fuel additive, has a number of advantages over ethyl alcohol: * ETBE is not hygroscopic * Similar to ethanol, ETBE reduces the formation of carbon monoxide (CO) and particulate matter. This is particularly evident in engines with direct fuel injection. [6] * Due to its low latent heat of vaporization and low boiling point, gasoline treated with ETBE does not create addi- tional problems with a cold start, especially in winter * Compared to ethanol, ETBE is a more effective octane- number enhancer for gasoline. The effective research octane number (RON) of ETBE is 119, whereas for etha- nol it is 109. [7] * The energy density of ETBE is only slightly lower than that of the standard gasoline, and hence blending with it does not decrease the gasoline volumetric energy content, which could cause consumer dissatisfaction. At the same time, gasoline blends with ethanol have appreciably lower volumetric energy densities, which lead the vehicle to have higher fuel consumption. Ethyl tert-butyl ether (ETBE) is a promising gasoline im- prover and this study shows its comparison with other pro- spective oxygenated fuel additives. ETBE synthesis and its economics are reviewed with emphasis on sustainable pro- duction. Furthermore, an experimental investigation is per- formed on the impact of employing relatively large propor- tions of ETBE in fuel blends and a particular emphasis is put on the magnitude of cyclic variations at different operating conditions. Tests involved a primary reference fuel (95PRF and two mixtures of ethyl tert-butyl ether (ETBE) with 95PRF. To provide a baseline for comparison, a commercial gasoline fuel containing 5 % by volume of ethanol (E05) was also tested. The experiments were performed by using a well-controlled single-cylinder research engine, which has a disc-shaped combustion chamber with a full-bore overhead optical access. The pressure recording method was used si- multaneously with natural-light video photography for re- cording the flame propagation. To quantify the cyclic varia- tions, the indicated mean effective pressure (IMEP), the peak pressure and the crank value at which it is attained, and the time for 90 % mass fraction burnt (MFB) were used. Increasing proportion of ETBE in the fuel has very little effect on both the average rate of combustion and its cyclic variability, regardless of what parameter is chosen to charac- terize the it. [a] M. E. Bardin, P. A. Gushchin, V. A. Vinokurov Division of Physical and Colloid Chemistry, Department of Chemistry Gubkin Russian State University of Oil and Gas Moscow (Russia) [b] A. M. T. A. El-Dein Hussin Department of Mechanical Power Engineering Ain Shams University Cairo (Egypt) [c] Dr. A. A. Burluka School of Mechanical Engineering University of Leeds Leeds, LS2 9JT (United Kingdom) E-mail: A.A.Burluka@leeds.ac.uk 194  2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim Energy Technol. 2014, 2, 194 – 204