A comparison of performance of higher alcohols/diesel fuel blends in a diesel engine Javier Campos-Fernández a , Juan M. Arnal b , Jose Gómez b , M. Pilar Dorado a,⇑ a Department of Physical Chemistry and Applied Thermodynamics, University of Cordoba, EPS, Edif. Leonardo da Vinci, Campus de Rabanales, Campus de Excelencia Internacional Agroalimentario, ceiA3, Spain b Department of Mechanization, IFAPA ‘‘Alameda del Obispo’’, Junta de Andalucia, Cordoba, Spain article info Article history: Received 6 October 2011 Received in revised form 12 February 2012 Accepted 20 February 2012 Available online 14 March 2012 Keywords: Engine power Brake specific fuel consumption Long-chain alcohols Fusel oil Fuel mixtures Biorefinery abstract The use of alcohols provides an attractive alternative fuel for internal combustion engines. Moreover, alcohol can be produced by biorefineries, thus reducing the consumption of fossil resources. Heretofore, research related to the use of alcohols as alternative fuels for internal combustion engines has been focused on the employment of short chain alcohols, mainly methanol and ethanol, blended with fossil fuels. Despite their adequate combustion properties, long chain alcohols like butanol or pentanol have been barely investigated. The objective of this work was to compare the short-term performance of a direct injection diesel engine fueled with different 1-butanol/diesel and 1-pentanol/diesel fuel blends, without any modifications of the engine. To gain knowledge about the implications of the use of the pro- posed blends, results were compared with those achieved with the use of neat diesel fuel. 1-butanol/die- sel fuel blends (from 10% to 30% of 1-butanol by volume) and 1-pentanol/diesel fuel blends (from 10% to 25% of 1-pentanol by volume) were tested. Experimental results showed a slight engine power loss and an increase in brake thermal efficiency when the engine was fueled with higher alcohols blends instead of straight diesel fuel. However, some 1-butanol blends depicted a decrease in the brake specific fuel con- sumption compared to the use of neat diesel fuel. After using 1-butanol blends and 1-pentanol blends, no engine performance problems were visually detected. Moreover, statistical analysis showed no signifi- cant differences between tests. It can be concluded from this field trial that a diesel engine, without any modifications, can run successfully on a blend up to 30% 1-butanol/70% diesel fuel or 25% 1-penta- nol/75% diesel fuel without externally apparent damage to the engine parts. Nevertheless, to recommend its use as a substitute of straight diesel fuel, long-term durability tests are needed. Ó 2012 Elsevier Ltd. All rights reserved. 1. Introduction Due to the increase and fluctuation in prices of diesel fuel and petrol, a growing environmental conscience and the shortage of petroleum, an alternative to fossil fuels is needed. Government policies in different countries are motivating the use of substitute fuels for petroleum-based ones. In fact, ‘‘Directive 2009/28/EC of the European Parliament and of the Council on the promotion of the use of energy from renewable sources’’ specifies that each Member State shall ensure that the share of energy from renew- able sources in all forms of transport in 2020 is at least 10% of the final consumption of energy in transport in that Member State. There is a growing interest on using alcohols to substitute diesel fuel, as the use of oxygenated fuels involves oxygen enrichment, enhancement of premixed combustion phase and improvement of the diffusive combustion phase [1,2]. However, some difficulties prevent their use as fuel for diesel engines, i.e. reduced lower heat- ing value (LHV) compared to diesel fuel, miscibility and stability problems when blended with diesel fuel [3], low cetane number (CN) and poor lubricating properties [4]. Moreover, alcohol can dilute the lubricant film on the piston wall, thus affecting engine durability. To solve the aforementioned disadvantages, different technolo- gies have been proposed. Considering ethanol is the most popular alternative, pulverization of ethanol [4,5], double injection of diesel fuel and ethanol [6], direct ethanol/diesel fuel blends [5,7,8] and emulsions [9,10] are among the most used alternatives. However, direct use of alcohol/diesel fuel blends is one of the most interest- ing possibilities because modifications on diesel engine are not necessary when low alcohol concentrations are used. For this rea- son, the target is to find both the most appropriate type of alcohol and the optimum alcohol/diesel fuel blend to substitute diesel fuel on diesel engines. Lower alcohols (ethanol and methanol) have been widely stud- ied as alternate fuels, although they depict solubility problems in diesel fuel [2,11]. Moreover, percentages of ethanol above 10% blended with diesel fuel usually reduce engine power [7,12,13] and increase brake specific fuel consumption (BSFC) [1,2,7,14]. The value of LHV, CN, self-ignition temperature (ST), vaporization latent heat (VLH) and other properties are established by the molec- ular structure of alcohols. From previous works, it may be inferred 0306-2619/$ - see front matter Ó 2012 Elsevier Ltd. All rights reserved. doi:10.1016/j.apenergy.2012.02.051 ⇑ Corresponding author. Tel.: +34 957 218332; fax: +34 957 218417. E-mail address: pilar.dorado@uco.es (M. Pilar Dorado). Applied Energy 95 (2012) 267–275 Contents lists available at SciVerse ScienceDirect Applied Energy journal homepage: www.elsevier.com/locate/apenergy