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Öğe Otomotiv fren balatalarının sürtünme performansında sic etkisi(Uludağ Üniversitesi, 2012-06) Altun, Şehmus; Öner, Cengiz; Sugözü, İlkerBu çalışmada, yüksek mukavemet, düşük aşınma, daha fazla yük ve sıcaklık dayanımı özelliklerine sahip SiC içeren balata numunelerinin sürtünme katsayısı ve aşınma dayanımına etkisi incelenmiştir. Balata bileşeni içerisine %5, %10 ve %15 SiC ilave edilmiştir. Sonuç olarak, SiC oranı arttıkça aşınma direnci artmış ve sürtünme katsayısı azalmıştırÖğe Biodiesel production from inedible animal tallow and an experimental investigation of its use as alternative fuel in a direct injection diesel engine(Elsevier, 2009-02-15) Altun, Şehmus; Öner, CengizIn this study, a substitute fuel for diesel engines was produced from inedible animal tallow and its usability was investigated as pure biodiesel and its blends with petroleum diesel fuel in a diesel engine. Tallow methyl ester as biodiesel fuel was prepared by base-catalyzed transesterification of the fat with methanol in the presence of NaOH as catalyst. Fuel properties of methyl ester, diesel fuel and blends of them (5%, 20% and 50% by volume) were determined. Viscosity and density of fatty acid methyl ester have been found to meet ASTM D6751 and EN 14214 specifications. Viscosity and density of tallow methyl esters are found to be very close to that of diesel. The calorific value of biodiesel is found to be slightly lower than that of diesel. An experimental study was carried out in order to investigate of its usability as alternative fuel of tallow methyl ester in a direct injection diesel engine. It was observed that the addition of biodiesel to the diesel fuel decreases the effective efficiency of engine and increases the specific fuel consumption. This is due to the lower heating value of biodiesel compared to diesel fuel. However, the effective engine power was comparable by biodiesel compared with diesel fuel. Emissions of carbon monoxide (CO), oxides of nitrogen (NOx), sulphur dioxide (SO2) and smoke opacity were reduced around 15%, 38.5%, 72.7% and 56.8%, respectively, in case of tallow methyl esters (B100) compared to diesel fuel. Besides, the lowest CO, NOx emissions and the highest exhaust temperature were obtained for B20 among all other fuels. The reductions in exhaust emissions made tallow methyl esters and its blends, especially B20 a suitable alternative fuel for diesel and thus could help in controlling air pollution. Based on this study, animal tallow methyl esters and its blends with petroleum diesel fuel can be used a substitute for diesel in direct injection diesel engines without any engine modification.Öğe Atık kızartma yağlarının alternatif dizel motor yakıtı olarak değerlendirilmesi(TMMOB Makina Mühendisleri Odası, 2011) Adin, Hamit; Yaşar, Fevzi; Altun, ŞehmusÖğe The comparison of engine performance and exhaust emission characteristics of sesame oil-diesel fuel mixture with diesel fuel in a direct injection diesel engine(Elsevier, 2008-01-09) Altun, Şehmus; Bulut, Hüsamettin; Öner, CengizThe use of vegetable oils as a fuel in diesel engines causes some problems due to their high viscosity compared with conventional diesel fuel. Various techniques and methods are used to solve the problems resulting from high viscosity. One of these techniques is fuel blending. In this study, a blend of 50% sesame oil and 50% diesel fuel was used as an alternative fuel in a direct injection diesel engine. Engine performance and exhaust emissions were investigated and compared with the ordinary diesel fuel in a diesel engine. The experimental results show that the engine power and torque of the mixture of sesame oil-diesel fuel are close to the values obtained from diesel fuel and the amounts of exhaust emissions are lower than those of diesel fuel. Hence, it is seen that blend of sesame oil and diesel fuel can be used as an alternative fuel successfully in a diesel engine without any modification and also it is an environmental friendly fuel in terms of emission parameters.Öğe The fuel properties of methyl esters produced from canola oil- animal tallow blends by basecatalyzed transesterification(Kırıkkale Üniversitesi, 2010-06) Altun, Şehmus; Yaşar, Fevzi; Öner, CengizBiodiesel is an alternative diesel fuel that can be produced from renewable feedstocks such as vegetable oil or animal fats by transesterification with methanol for using in diesel engines. The viscosity and density of biodiesel fuels are important parameters due to being key fuel properties for injection and combustion process of diesel engines. These fuel properties mainly depend on the feedstock which is used in the biodiesel production. In this study, the blends containing 0, 25, 50, 75 and 100% of food-grade canola oil/inedible animal tallow in volume basis were prepared and converted into methyl esters by base-catalyzed transesterification. Effect of inedible animal tallow-canola oil blends on the viscosity and density of methyl esters were investigated. Experimental results showed that the kinematics viscosity of methyl esters increased as animal tallow ratio increased in the feedstock. Besides, it was observed that density did not change muchÖğe Onarımda kullanılan darbe dayanımlı iki bileşenli yapıştırıcılar(Fırat Üniversitesi, 2011) Adin, Hamit; Altun, Şehmus; Yaşar, FevziÖğe Biodiesel properties of microalgae (Chlorella protothecoides) oil for use in diesel engines(Taylor & Francis, 2018-09-08) Yaşar, Fevzi; Altun, ŞehmusIn this study, biodiesel was produced from a microalgae oil, chlorella protothecoides, by typical alkali-catalyzed transesterification in conditions such as a 0.75 wt.% KOH of the oil as catalyst, 68°C and 80 min which was agreed as optimal conditions after investigating the effect of KOH concentration, reaction temperature and time at constant molar ratio of 6:1 on the conversion rate and fuel properties. Under these conditions, a 98.6% conversion rate of algae oil to its methyl ester was achieved with ester content higher than 96%. Furthermore, all physicochemical properties met the requirements of international biodiesel standards, EN 14214 and ASTM D 6751, with some remarkable ones such as high cetane number (57.3) and low CFPP (−10°C). The effect of microalgae biodiesel volume fraction in the fuel on the kinematic viscosity, CFPP, lubricity, density, and distillation temperature was also studied. A blending ratio of the algal-biodiesel up to 50% (v/v) was also found in agreement with the standards for biodiesel-diesel blends. From GC analysis, oleic and linoleic acids were found to be major fatty acids, and then the oxygen extended sooting index and adiabatic flame temperature were calculated using fatty acid distribution for evaluating the main diesel emissions such as soot and NO. As a result, the algae oil studied here was found to be an appropriate raw material for producing biodiesel and for using in Diesel Engines and its properties are within the typical ranges of conventional biodiesel fuels.Öğe Prediction of performance and exhaust emissions of a diesel engine fueled with biodiesel by using linear regression and artificial neutral networks(University of Sarajevo, 2016) Altun, Şehmus; Ertuğrul, Ömer FarukÖğe A comparison of performance and emissions of a diesel power generator fueled with biodiesels from waste frying oils(The International University of Sarajevo, 2013) Altun, Şehmus; Yaşar, FevziÖğe Exhaust emissions from a spark-ıgnition engine operating on Iso-propanol and unleaded gasoline blends(Technology, 2010) Altun, Şehmus; Öner, Cengiz; Fırat, MüjdatIn this study, the effect of blends of iso-propanol and unleaded gasoline on exhaust emissions of a sparkignition engine were experimentally investigated. Exhaust emission tests were conducted on a four-stroke, four cylinder and direct injection spark-ignition engine. The engine tests were performed at three-fourth throttle opening position at four various speeds in the range of 1000-4000 rpm with 1000 rpm period. The experimental results compared with unleaded gasoline showed that emissions of carbon monoxide (CO) and hydrocarbon (HC) decreased with iso-propanol-unleaded gasoline blends while carbon dioxide (CO2) emission increased.
