Oil filter modification for biodiesel–fueled engine: A pathway to lubricant sustainability and exhaust emissions reduction M. Gulzar ⇑ , H.H. Masjuki ⇑ , M.A. Kalam, M. Varman, I.M. Rizwanul Fattah Centre for Energy Sciences, Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia article info Article history: Received 15 October 2014 Accepted 28 November 2014 Available online 19 December 2014 Keywords: Strong base filter Palm biodiesel Sustainability Drain interval Piston ring Engine emissions abstract The widespread use of biodiesel in internal combustion engines promotes frequent lubricant drain inter- vals which in turn affects lubricant sustainability and engine performance. In this research two endur- ance tests were carried out to evaluate the novel approach of strong base oil filter with palm biodiesel (PME) fueled single-cylinder diesel engine. The effects of strong base filter on lubricant rheology, piston ring/cylinder wear losses, engine performance and exhaust emissions were investigated. The results of long duration engine testing showed that the strong base filter improved the lubricant’s physical and tri- bological characteristics. Tribo-testing, using high stroke reciprocating test rig, proved that the mechan- ical energy losses due to piston ring-cylinder interaction were reduced significantly. Finally, the engine performance and exhaust emissions analysis for strong base filter testing showed an improvement in engine performance, average decrease of 2.78% in carbon monoxide (CO) emissions, 7.18% reduction in hydrocarbon (HC) emissions and 3.3% reduction in smoke opacity at full load engine conditions. Ó 2014 Elsevier Ltd. All rights reserved. 1. Introduction With the increasing environmental legislations, tribologists and researchers are looking for environment friendly lubrication alter- natives. However industrial and transport sector is majorly depen- dent on petroleum based lubricants. As a result yearly millions of tons of oil wastes are exposed to environment which are toxic and non-biodegradable [1]. As the crude oil resources are depleting worldwide, the efficient use of lubricants is the requirement to meet the cost and environmental legislations [2]. The problem of short useful lubricant life is serious in diesel engines where the lubricant is degraded by contaminations such as soot, water, metal particles and acid by-products of fuels. During normal engine oper- ations, the engine oil is exposed to combustion gases and carbon based acids. In such situations, the oxidation of base oil results in accumulation of the weak organic acids in the engine oil. The prob- lem becomes more intense for biodiesel operated engines where the researchers have reported increased dilution and polymeriza- tion of engine oil which in turn requires more frequent oil changes [3–5]. The related problems include high carbon deposits, piston oil ring sticking, and increased engine oil viscosity [3,6]. In order to improve the useful life and performance of engine oil, the neutralization of high concentrations of weak acids is required in biodiesel fueled engines. Currently in industry the acidity is the key factor to indicate the oil change in diesel engines and drain interval is mostly taken as engine oil ability to control the acids. With the widespread use of biodiesel as an alternative energy source, the lubricant drain interval is decreased. The esters avail- able in biodiesels are hydrolyzed to increase the concentrations of weak acids in the lubricants [4,5,7]. The quality of lubricant affects the wear and friction of engine components as well as the engine performance and engine exhaust emissions [8]. The amount of unburned lubricant has been proved to be a predominant con- tributor to undesirable paraffins and hydrocarbons emissions [9]. Many techniques are in practice currently to maintain the lubricant physicochemical and tribological characteristics. By pass filtration and slow additive release filters are two filter technolo- gies currently being used to improve oil drain intervals [10]. In by pass filtration technique the contamination particles are removed mechanically, leaving the acidic contaminants untrapped. On the other hand, control over release rate is the main shortcom- ing in the filter technology which is based upon slow release of additives like detergents, dispersants and antioxidants. The accu- mulation of these additives increases ash content in lubricant. To address the issues mentioned in the currently practiced filter tech- nologies, the effectiveness of novel approach of chemical modifica- tion of oil filter element has been highlighted by the various earlier http://dx.doi.org/10.1016/j.enconman.2014.11.055 0196-8904/Ó 2014 Elsevier Ltd. All rights reserved. ⇑ Corresponding authors. Tel.: +60 3 79674448; fax: +60 379675317 (M. Gulzar). Tel.: +60 3 7967 5245; fax: +60 379675317 (H.H. Masjuki). E-mail addresses: mubashir_nustian@hotmail.com (M. Gulzar), masjuki@um. edu.my (H.H. Masjuki). Energy Conversion and Management 91 (2015) 168–175 Contents lists available at ScienceDirect Energy Conversion and Management journal homepage: www.elsevier.com/locate/enconman