7 sonuçlar
Arama Sonuçları
Listeleniyor 1 - 7 / 7
Öğe Exhaust emissions of methanol and ethanol-unleaded gasoline blends in a spark ignition engine(VINCA Institute of Nuclear Sciences, 2013) Altun, Şehmus; Öztop, Hakan Fehmi; Öner, Cengiz; Varol, YasinIn this study, the effect of unleaded gasoline and unleaded gasoline blended with 5% and 10% of ethanol or methanol on the performance and exhaust emissions of a spark-ignition engine were experimentally investigated. The engine tests were performed by varying the engine speed between 1000 and 4000 rpm with 500 rpm period at three-fourth throttle opening position. The results showed that brake specific fuel consumption increased while brake thermal efficiency, emissions of carbon monoxide and hydrocarbon decreased with methanol-unleaded gasoline and ethanol-unleaded gasoline blends. It was found that a 10% blend of ethanol or methanol with unleaded gasoline works well in the existing design of engine and parameters at which engines are operating.Öğe Biofuels derived from Turkish industry wastes - A study of performance and emissions in a diesel engine(Wiley-Blackwell, 2015-08-13) Altun, Şehmus; Rodríguez-Fernández, JoséRecently, research has focused on the biofuel production from local industrial wastes due to the risk of greenhouse emissions derived from land-use change (both directly and indirectly) of conventional feedstock and the social concern about the effect of conventional biofuel production on oil prices and its availability (the so-called food vs. fuel debate). Therefore, with the aim to evaluate the use of biofuels derived from wastes from traditional manufacturing industries in Turkey, biodiesel fuels from leather fat, obtained as a by-product in the leather industry, waste anchovy fish oil, derived from the fish-processing industry, and waste frying cottonseed oil achieved from food industry, have been tested in a three-cylinder DI diesel engine at a steady-state condition. In a previous work, the viability of these fuels was evaluated by analyzing measured and estimated properties and indicators for main diesel emissions, and recommendations were made on their alternative use to conventional biodiesels with the benefit of potentially lower life-cycle greenhouse emissions. The experimental results, which were compared with ULSD operation, demonstrated that the engine performance was not significantly affected, while a substantial change in emissions was observed with the use of biofuels. In general, the emission results reported here are in a similar range to those obtained with the use of conventional biodiesel fuels. Nonetheless, the exact magnitude of these changes depended upon the biodiesel origin. Lubricity of alternative biofuels was also tested, revealing an enormous capacity for protecting the fuel system from wear, in line with conventional biodiesel fuels.Öğe Comparison of methanol, ethanol, or n-butanol blending with unleaded gasoline on exhaust emissions of an SI engine(Taylor & Francis, 2014-03-18) Altun, Şehmus; Varol, Yasin; Öner, Cengiz; Öztop, Hakan FehmiAir pollution is becoming a serious problem in many urban cities of the world and it can have a serious effect on both health and the environment. Although experimental studies have shown that alcohol fuels burn cleaner than unleaded gasoline and produce lesser emission, there is limited information regarding the comparison among the alcohol fuels as gasoline additive in spark-ignited engines. Therefore, a comparison has been performed in this experimental work on the exhaust emissions of a spark-ignited engine when operating on a blend of methanol, ethanol, or n-butanol with unleaded gasoline. Methanol, ethanol and n-butanol were added to unleaded gasoline by mass percent of 10% (denoted as M10, E10 and Bu10, respectively), and then tested in a four cylinder, four strokes spark-ignited engine. Although the experimental results show little differences in exhaust emissions between M10, E10, and Bu10, compared with Bu10, M10 and E10 have lower carbon monoxide emission and higher fuel consumption, hydrocarbon, and CO2 emission. Compared with unleaded gasoline, blended fuels containing different alcohols appear to have a lower carbon monoxide and hydrocarbon emissions and a higher fuel consumption rate and CO2 emissions.Öğe Effects of isopropanol-butanol-ethanol (IBE) on combustion characteristics of a RCCI engine fueled by biodiesel fuel(Journals & Books, 2021-10) Altun, Şehmus; Okcu, Mutlu; Varol, Yasin; Fırat, MüjdatThe reactivity controlled compression ignition (RCCI) strategy using fuels with different reactivity’s has attracted attention due to its high thermal efficiency as well as very low NOx and PM emissions in comparison to conventional combustion. As previous studies have shown that the type and amount of low reactivity fuel have a significant contribution to the in-cylinder reactivity, thus RCCI combustion, in this study, Iso-Propanol-Butanol-Ethanol (IBE), which has comparable characteristics to n-butanol and ethanol, is employed as low reactivity fuel (LRF) in a RCCI engine fueled by petroleum based EN590 fuel and commercial biodiesel. The IBE mixture was in volumetric ratios of 3:6:1 as in the fermentation process of butanol, that is to say; 30% Iso-Propanol, 60% Butanol and 10% Ethanol. In each experimental condition, keeping the total energy of the fuel supplied to the engine in conventional combustion mode for each cycle as constant, the premixed ratio (Rp) in case RCCI combustion was applied as 0%, 15%, 30%, 45% and 60% (the amount of LRF in energy basis) over this energy amount. The effect of premixed ratio of IBE on combustion characteristics were investigated in a single-cylinder RCCI engine under different loads with using both petroleum diesel and biodiesel as high-reactivity fuels (HRF), respectively. According to experimental results, a higher in-cylinder pressure was measured by using diesel in both conventional and RCCI mode compared to the use of biodiesel. Considering the peak in-cylinder pressure and rate of heat release, the premixed ratio (Rp) of up to 45% was found as optimum for all loads while it was up to 30%Rp for the NOx emissions. In addition, the biodiesel-fueled RCCI engine produced the lowest smoke opacity in all loads and it gradually decreased by up to 97% with the application of the RCCI strategy. Furthermore, the results showed that a simultaneous reduction in NOx and smoke opacity could be obtained under 60% load and up to 30% Rp with a marginal increase in unburned HC emissions.Öğe Investigation of the effect of barium-based additive on smoke and NOx emissions of a diesel engine fueled with conventional and biodiesel fuels(SpringerLink, 2020-06-13) Altun, Şehmus; Arca Batı, ZülalNowadays, increasing energy demand and environmental and air pollution issues have spread the use of alternative fuels such as biodiesel in diesel engines. While the advantages of biodiesel that are comparable to petroleum-based diesel fuels and low unburned HC, carbon monoxide and smoke (soot) emissions make the use of this fuel environmentally signifcant; high NOx emissions are still a problem to be solved. The formation of decreased smoke reducing radiative heat transfer from combustion chamber in biodiesel engines and increase in formation of NOx due to rise in fame temperature are among the reasons reported for high NOx in the literature. In this study, in a diesel engine using biodiesel, soot emissions produced by petroleum diesel fuel were reduced to biodiesel level by using metallic additive (Ba), and NOx emissions were compared. When the amount of Ba in the fuel was increased, there was a signifcant decrease in the smoke emissions, but in this case, NOx emissions decreased slightly, while they were expected to increase. When NOx emissions of diesel and biodiesel were compared for the same or similar smoke emissions, it was seen that high NOx emissions were achieved with biodiesel. As a result, although Ba additive reduced smoke emissions, it was seen that its efect on NOx formation was not very clear.Öğe The effect of microalgae biodiesel on combustion, performance, and emission characteristics of a diesel power generator(VINCA Institute of Nuclear Sciences, 2018) Yaşar, Fevzi; Altun, ŞehmusMicroalgae oil is expected to be a relevant source of biofuel in the future as it is more favorable to confront the problems of food shortages and greenhouse emission challenges raised by conventional biofuels. Therefore, in this study, a most common kind of microalgae that have a great potential, Chlorella protothecoides, was evaluated as fuel in terms of its combustion and emission characteristics in a Diesel engine-powered generator set at constant engine speed of 1500 rpm under various loads after converting its oil to biodiesel by typical base-catalyzed transesterification process. A biodiesel/diesel blend at the rate of 20% by volume was tested too. According to results obtained, using biodiesel resulted in an increase in fuel consumption, in a slight reduction of efficiency, and in sharp reductions in both unburned hydrocarbon emissions and smoke opacity especially at light loads, despite increasing NOx emissions were observed when compared with conventional petroleum diesel. In addition, premixed combustion ratio was higher for biodiesel than for diesel while total combustion duration took shorter for biodiesel especially at higher loads. The overall results of the study reveals that the combustion parameters of the biodiesel studied here are within the typical ranges of conventional biodiesel fuels.Öğe Gaseous emission comparison of a compression-ignition engine fueled with different biodiesels(Islamic Azad University of Research and Technology, 2012-12-14) Altun, Şehmus; Öner, CengizIn this study, it was performed a comparison of the performance and emissions of two methyl ester fuels: one obtained from animal fat and the other from crude canola oil, in a compression-ignition engine against diesel fuel. The experimental results compared with diesel fuel showed that significant reductions could be obtained by biodiesel derived from animal fat in carbon monoxide and oxides of nitrogen emissions. Carbon dioxide emissions showed a trend of decreasing with the biodiesel fuels. An increase in brake specific fuel consumption was observed for different biodiesel fuels when compared with diesel fuel. It was concluded that animal tallow methyl ester performed better than canola oil methyl ester, whereas slightly higher brake torque is observed with canola oil methyl ester.
