Combustion and emission characteristics of n-butanol/diesel fuel blend in a turbo-charged compression ignition engine Lennox Siwale a,⇑ , Lukács Kristóf b , Torok Adam b , Akos Bereczky b , Makame Mbarawa c , Antal Penninger b , Andrei Kolesnikov a a Department of Mechanical Engineering, Tshwane University of Technology, Private Bag X680, Pretoria 0001, South Africa b Department of Energy Engineering, Budapest University of Technology and Economics, H-1111 Budapest, Bertalan Lajos u. 4–6, D208, Hungary c Ministry of Communication, Science and Technology, Jamhuri Street, P.O. Box 2645, Dar es Salaam, United Republic of Tanzania highlights " Regulated emissions were compared with other similar study by other authors using biodiesel blending with diesel fuel. " There was great improvement in the reduction of the emissions using a small shared volume of n-butanol with diesel fuel. " Premixed combustion phase is distinguishable and amplified suggesting an effective air-to-fuel mixing process. " We recommended the use of n-butanol/diesel blend in a turbo-charged engine without any engine modifications. article info Article history: Received 14 August 2012 Received in revised form 22 October 2012 Accepted 27 November 2012 Available online 19 December 2012 Keywords: Compression ignition Diesel Emission reduction Butanol (-n) Global climate change abstract Burning of 5%, 10%, and 20% shared volume of n-butanol (B05, B10, and B20, where B05 represents 5% shared volume of n-butanol with 95% diesel fuel) with diesel fuel (DF) in a high load, light duty, turbo-charged diesel engine is reported. The aim was to compare the effects of the blends on the engine combustion characteristics and regulated emissions namely nitrogen oxides (NO x ), unburned hydrocar- bon (UHC), carbon monoxide (CO) and soot results from this study with a similar past study: (30% rape- seed oil methyl esters (RMEs) shared volume with similar diesel fuel admixed to 5% or 7.5% bioethanol). Using n-butanol shared volume, B05, B10 and B20 significantly improved the reduction of regulated emissions compared to the other study. In this study the reduction or increase percentage relative to DF was as follows at 75% load at 1500 rpm for B5, B10, B20 mixtures: soot reduction was 55.5%, 77.8%, and 85.1% respectively; CO reduction was 35.7%, 57.1% and 71.4%; NO x increase was 10.3%, 32.3% and 54.4% ; UHC increase, 21.4%, 71.4%, 214% respectively. The premixed phase combustion was amplified and distinguishable with increase of shared volume of n-butanol in DF. The combustion cycles of the blends were more stable than the cycles of DF. Ó 2012 Elsevier Ltd. All rights reserved. 1. Introduction Environmental degradation of petroleum products and their non-renewable nature has led to a world-wide search for renew- able and greener alternatives in internal combustion. Such alterna- tives which include biofuels [1] have in general the advantage of reducing most of the regulated emissions such as nitrogen oxides (NO x ), unburned hydrocarbons (UHC), soot, carbon monoxide [2–4] in reciprocating engines. It has been shown [5] that biofuels and several cell electric vehicles are the best options in reducing greenhouse gases by 80% or more below the 1990 levels in the transportation sector. Biofuels, which include oxygenated additives such as ethers, esters, and bioalcohols, have been added to diesel fuel [6]. In gasoline engines biobutanol has been studied and dis- cussed as potential fuel [7–10]. Some studies exist where vegetable oils were blended with ethanol and n-butanol to test diesel engine performance. Butanol/diesel was used in a light-duty turbo diesel vehicle [4,11]. Different blend ratios and amounts of regulated emissions have been reported in literature. The nature of the fuel [12] has a significant influence on the com- bustion and emissions generated in internal combustion engines. To minimize concentration of emissions in exhaust gases, bioalco- hols could be used. Bioalcohols are oxygenated fuels that form part of the biofuel family. Oxygenated fuels have drawn the attention of many researchers due to the ability to drastically reduce particulate matter (PM) emission without altering the emission levels of other regulated emissions. Most studies have focused the use of ethanol 0016-2361/$ - see front matter Ó 2012 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.fuel.2012.11.083 ⇑ Corresponding author. Tel.: +27 764422347/12 382 5164; fax: +27 12 382 5602. E-mail address: zumbe.siw@gmail.com (L. Siwale). Fuel 107 (2013) 409–418 Contents lists available at SciVerse ScienceDirect Fuel journal homepage: www.elsevier.com/locate/fuel