Producing and using renewable fuels for transportation is one approach for sustainable energy future for the world. A renewable fuel contributes lesser global climate change. In this study the effect of using liquefied petroleum gas (LPG) as a primary fuel with two different ignition enhancers diethyl ether (DEE) and dimethyl ether (DME) on performance, combustion and emissions characteristics of a single cylinder, four-stroke, water-cooled naturally aspirated DI diesel engine was carried out. LPG has a simpler hydrocarbon structure than conventional fuels. DEE and DME are recently reported as a renewable fuel and to be a low-emission high-quality diesel fuel replacement. A single cylinder, four-stroke, water-cooled naturally aspirated DI diesel engine having rated output of 3.7kW at 1500 rpm was used for the experiments. Measurements were made to study the performance, combustion and emissions characteristics and to compare between these two ignition enhancers and conventional diesel fuel. From the results, it is observed that using LPG/DEE was better than LPG/DME on performance, combustion and emissions characteristics of diesel engine and both were better than conventional diesel fuel, especially in a reduction of NO, smoke and particulate emissions. The brake thermal efficiency for both LPG/DEE and LPG/DME lower at full load with a reduction of NO emission than the diesel operation. The maximum reduction in smoke and particulate emissions is observed at high loads, when compared to that of diesel operation; however an increase in CO and HC emissions was observed.

Diesel engine, DI, LPG, DEE, DME, Combustion, Emissions, Characteristics

[1]. YADAV R, Rajay S. A text book of internal combustion engines and air pollution, 1st ed. Allahabad: Central Publishing House; 2002, p. 672.
[2]. Kontarakis G, Collings N. Demonstration of HCCI using a single cylinder four-stroke SI engine with modified valve timing, SAE transaction 2001-01-2870.
[3]. Nagarajan G, Rao AN, Renganarayanan S. Emission and performance characteristics of neat ethanol fuelled DI diesel engine, Int J Ambient Energy 2002; 23(8).
[4]. Hashimoto K, Ohta H, Hirasawa T, Arai M, Tamura M. Evaluation of ignition quality of LPG with cetane number improver, SAE transaction 2002-01-0870.
[5]. Zhao FF. Homogeneous charge compression ignition (HCCI) engine: key research and development issues. Warrendale, PA, USA:Society of Automotive Engineers, Inc.;2003.
[6]. Kajitani CL, Oguma C, Alam M, Rhee KT. Direct injection diesel engine operated with propane�DME blended fue, SAE transaction 982536, 1998.
[7]. Zhili C, Konno M, Oguna M, Tadanori Y. Experimental study of CI natural gas/DME homogenous charge engine, SAE transaction 2000-01-0329.
[8]. Lida N, Igarashi T. Auto-ignition and combustion of n-butane and DME/air mixtures in a homogeneous charge compression ignition engine, SAE transaction 2000-01-1832.
[9]. Alam M, Goto S, Sugiyama K, Kajiwara M, Mori M, Konno M, et al. Performance and emissions of a DI diesel engine operated with LPG and ignition improving additives, SAE transaction 2001-01-3680.
[10]. Goto S, Lee D, Wakao Y, Honma H, Mori M, Akasaka Y, et al. Development of an LPG DI diesel engine using cetane number enhancing additives, SAE transaction 1999-01-3602.
[11]. Bailey B, Eberhardt J, Goguen S, Erwin J. Diethyl ether (DEE) as a renewable diesel fuel, SAE transaction 972978, 1997.
[12]. Jajoo BN, Mahajan SD, Matale AP. Experimental investigations on the performance and control of smoke emission by dual fuelling diesel engine using LPG. In: Proceedings of IC engines and combustion 2000, New Delhi, India.
[13]. Heywood JB. Internal combustion engine fundamentals, New York: McGraw-Hill; 1998.
[14]. Lida N, Igarashi T. Auto-ignition and combustion of n-butane and DME/AIR mixtures in a homogeneous charge compression ignition engine, SAE transaction 2000-01-1832.
[15]. Doebelin A. Measurement systems: application and design. New York: McGraw-Hill; 1966.
[16]. Holman JP. Experimental methods for engineers, 6th ed. New York: McGraw-Hill; 1994.