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1.
Determining the speed of sound, density and bulk modulus of rapeseed oil, biodiesel and diesel fuel
Boban Nikolić, Breda Kegl, Saša Marković, Melanija Mitrović, 2012, original scientific article

Abstract: Modern tendencies in the development of diesel engines include the operation of the system for injecting diesel fuel at pressures higher than 100 MPa. Knowing the characteristics of liquid fuels such as speed of sound, bulk modulus and density depending on pressure, is important for predicting the behavior of fuel injection systems for diesel engines and optimization of the same. The paper presents an original method and apparatus (device) for determining the speed of sound and density of fluids depending on the pressures. With this method, values of these characteristics for rapeseed oil, biodiesel and conventional diesel fuel at pressures up to 160 MPa are determined. The method is non-destructive, it can also be applied to higher pressures than 160 MPa, as well as other liquid fluids that are used at high pressure - hydraulic oil, for example.
Keywords: biodiesel, rapeseed oil, speed of sound, bulk modulus, density, high pressure
Published: 07.07.2017; Views: 636; Downloads: 286
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2.
Uporaba alternativnih virov energije v prometu
Blaž Jaklič, 2012, undergraduate thesis

Abstract: V diplomski nalogi smo raziskovali uporabo alternativnih virov energije v prometu. Opravili smo primerjalno analizo smotrnosti nakupa dostavnih vozil z dieselskim motorjem z nakupom dostavnih vozil z bencinskim motorjem in vgradnjo plinske napeljave. Predstavili smo dve vrsti trenutno najbolj uporabljenih tekočih biogoriv, in sicer bioetanol in biodiesel, njune škodljive vplive na okolje ter prednosti in omejitve njune proizvodnje in uporabe. V nalogi smo predstavili tudi delovanje in uporabo vozil na vodik in električni pogon.
Keywords: plin, alternativni viri energije, bioetanol, biodiesel, vozila na vodik, električna vozila
Published: 27.10.2012; Views: 2077; Downloads: 243
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3.
Biodiesel usage at low temperature
Breda Kegl, 2008, original scientific article

Keywords: internal combustion engines, buses, biodiesel fuel, rapeseed oil, fuel injection system, low temperatures
Published: 01.06.2012; Views: 1167; Downloads: 83
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4.
Effects of biodiesel on emissions of a bus diesel engine
Breda Kegl, 2008, original scientific article

Abstract: This paper discusses the influence of biodiesel on the injection, spray, and engine characteristics with the aim to reduce harmful emissions. The considered engine is a bus diesel engine with injection M system. The injection, fuel spray, and engine characteristics, obtained with biodiesel, are compared to those obtained with mineral diesel (D2) under various operating regimes. The considered fuel is neat biodiesel from rapeseed oil. Its density, viscosity, surface tension, and sound velocity are determined experimentally and compared to those of D2. The obtained results are used to analyze the most important injection, fuel spray, and engine characteristics. The injection characteristics are determined numerically under the operating regimes, corresponding to the 13 mode ESC test. The fuel spray is obtained experimentally under peak torque condition. Engine characteristics are determined experimentally under 13 mode ESC test conditions. The results indicate that, by using biodiesel, harmful emissions (NOx, CO, smoke and HC) can be reduced to some extent by adjusting the injection pump timing properly.
Keywords: biodiesel, bus diesel engine, emissions
Published: 01.06.2012; Views: 864; Downloads: 63
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5.
Biodiesel influence on tribology characteristics of a diesel engine
Stanislav Pehan, Marta Svoljšak, Marko Kegl, Breda Kegl, 2009, original scientific article

Abstract: This paper deals with the influence of biodiesel on some tribology characteristics of a bus diesel engine with a mechanically controlled fuel injection system. The tests have been performed on a fully equipped engine test bed, on a fuel injection test bed and on a discharge coefficient testing device. The tested fuel was neat biodiesel produced from rapeseed. Attention was focused on the biodiesel influence on the pump plunger surface roughness, on the carbon deposits in the combustion chamber, on the injector and in the injector nozzle hole. The pump plunger surface was analyzed by experimentally determined roughness parameters and by a microscope. The carbon deposits at fuel injector and in the combustion chamber were examined using endoscopic inspection. The deposits in the injector nozzle were investigated indirectly by measuring the nozzle discharge coefficient. Numerical simulation has been performed in order to estimate the influence of the discharge coefficient variation on the computed injection characteristics. The obtained results indicate that biodiesel usage may even improve the pump plunger lubrication conditions. Furthermore, the carbon deposits in the combustion chambers did not vary significantly in quantity but they were noticeably redistributed. Finally, it was found out that the variation of the nozzle discharge coefficient has to be taken into account only if high accuracy of numerical simulation is desired.
Keywords: biodiesel, surface roughness, carbon deposits
Published: 01.06.2012; Views: 1595; Downloads: 75
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6.
Comparative study of various renewable fuels blends to run a diesel power plant
Eloisa Torres Jiménez, Marta Svoljšak, Andreja Gregorc, M. P. Dorado, Breda Kegl, 2010, published scientific conference contribution

Abstract: In this paper bioethanol/diesel and bioethanol/biodiesel blends, at several concentrations and temperatures, are studied to find its possible commercial usage as a fuel to run a diesel power plant. The tested fuels were: net mineral diesel fuel (D100) , 5 % bioethanol/diesel fuel blend (v/v) (E5D95), 10 % bioethanol/diesel fuel blend (v/v) (E10D90), 15 % bioethanol/diesel fuel blend (v/v) (E15D85), neat biodiesel (B100), 5 % bioethanol/biodiesel blend (v/v) (E5B95), 10 % bioethanol/biodiesel blend (v/v) (E10B90), and 15 % bioethanol/biodiesel blend (v/v) (E15B85). The fuels were tested at: 30, 25, 8and -18 C. This paper shows the observations done in 8 samples during 5 weeks. After each week, each sample was overviewed, and changes related to stability, colour and aggregation were recorded. It has been proved that additives are not necessary to ensure stability of bioethanol/biodiesel blends under low temperature conditions, as the phase separation never happens.But in case of bioethanol/diesel blends some additives are necessary to keep stability under low temperature conditions. Based on this study, it can be concluded that blends of biodiesel fuel with bioethanol up to 15% can be used to fuel a diesel power plant if engine performance tests corroborate it. The same conclusion can be applied to blends of diesel fuel with bioethanol up to 15% blends if additives to keep stability are added.
Keywords: alternative fuel, biodiesel, bioethanol, heat engines, fuels blend
Published: 31.05.2012; Views: 1257; Downloads: 0

7.
Comparative study of various renewable fuels blends to run a diesel power plant
Eloisa Torres Jiménez, Marta Svoljšak, Andreja Gregorc, M. P. Dorado, Breda Kegl, 2010, published scientific conference contribution

Abstract: In this paper bioethanol/diesel and bioethanol/biodiesel blends, at several concentrations and temperatures, are studied to find its possible commercial usage as a fuel to run a diesel power plant. The tested fuels were: net mineral diesel fuel (D100) , 5 % bioethanol/diesel fuel blend (v/v) (E5D95), 10 % bioethanol/diesel fuel blend (v/v) (E10D90), 15 % bioethanol/diesel fuel blend (v/v) (E15D85), neat biodiesel (B100), 5 % bioethanol/biodiesel blend (v/v) (E5B95), 10 % bioethanol/biodiesel blend (v/v) (E10B90), and 15 % bioethanol/biodiesel blend (v/v) (E15B85). The fuels were tested at: 30, 25, 8 and -18 C. This paper shows the observations done in 8 samples during 5 weeks. After each week, each sample was overviewed, and changes related to stability, colour and aggregation were recorded. It has been proved that additives are not necessary to ensure stability of bioethanol/biodiesel blends under low temperature conditions, as the phase separation never happens. But in case of bioethanol/diesel blends some additives are necessary to keep stability under low temperature conditions. Based on this study, it can be concluded that blends of biodiesel fuel with bioethanol up to 15% can be used to fuel a diesel power plant if engine performance tests corroborate it. The same conclusion can be applied to blends of diesel fuel with bioethanol up to 15% blends if additives to keep stability are added.
Keywords: alternative fuels, biodiesel, bioethanol, heat engines, fuels blend
Published: 31.05.2012; Views: 1654; Downloads: 0

8.
Influence of biodiesel on injection, fuel spray, and engine characteristics
Breda Kegl, Stanislav Pehan, 2008, original scientific article

Abstract: This paper discusses the influence of biodiesel on the injection, spray, and engine characteristics with the aim to reduce harmful emissions. The considered engine is a bus diesel engine with injection M system. The injection, fuel spray, and engine characteristics, obtained with biodiesel, are compared to those obtained with mineral diesel under peak torque and ratedconditions. The considered fuel is neat biodiesel from rapeseed oil. Its density, viscosity, surface tension, and sound velocity are determined experimentally and compared to those of mineral diesel. The experimentally obtained results are used to analyze the most important injection, fuel spray, and engine characteristics. Furthermore, the influence of biodiesel usage on lubrication is presented briefly. The results indicate that, by using biodiesel, harmful emissions (NOx, CO, HC, smoke, and PM) can be reduced to some extent by adjusting the injection pump timing properly while keeping other engine characteristics within acceptable limits. Furthermore, the results indicate better lubrication conditions when biodiesel is used.
Keywords: biodiesel, diesel engine, injection characteristics, fuel spray, emission, lubrication
Published: 31.05.2012; Views: 1309; Downloads: 271
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9.
Heat integration between two biodiesel processes using a simple method
Anita Kovač Kralj, 2008, original scientific article

Abstract: Biodiesel is a clean-burning alternative fuel, produced from domestic, renewable resources. Biodiesel can be blended at any level with petroleum diesel to create a biodiesel blend. It can be used in compression-ignition (diesel) engines with little or no modification. Biodiesel is simple to use, biodegradable, nontoxic, and essentially free of sulfur and aromatics. This paper presents heat integration between two biodiesel processes. Biodiesel can be produced by the esterification of different fatty acids (high and low boiling point) with alcohols. This simple method for heat integration is based on three possible steps. Simultaneous integration between processes can be performed using a stagewise model with a mixed integer nonlinear programming (MINLP) algorithm (step 3), which can include alternatives suggested by pinch analysis of heat transfer between the processes (step 2). The internal integration of individual processes can be performed in step 1. The fraction can be calculated for maximum integration between processes. Integration between the processes can be carried out using all three steps or by the first and third steps or by the last step only, depending on the problems' complexities. This method includes streams of different processes which are heated or cooled using a utility only. The existing heaters and coolers can be left unchanged in their original processes or can be used for integrating heat between processes, with hot and cold utilities being saved. This approach is illustrated by integrating two simulated biodiesel processes.The objective was to maximize additional annual profit for integration between processes by USD8300/a.
Keywords: chemical processing, biodiesel producing, heat integration, nonlinear programming
Published: 31.05.2012; Views: 1449; Downloads: 67
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10.
Investigation into the effect of different fuels on ignition delay of M-type diesel combustion process
Dževad Bibić, Ivan Filipovič, Aleš Hribernik, Boran Pikula, 2008, original scientific article

Abstract: An ignition delay is a very complex process which depends on a great number of parameters. In practice, definition of the ignition delay is based on the use of correlation expressions. However, the correlation expressions have very often limited application field. This paper presents a new correlation which has been developed during the research project on the direct injection M-type diesel engine using both the diesel and biodiesel fuel, as well as different values of a static injection timing. A dynamic start of injection, as well as the ignition delay, is defined in two ways. The first approach is based on measurement of a needle lift, while the second is based on measurement of a fuel pressure before the injector. The latter approach requires calculation of pressure signals delay through the fuel injection system and the variation of a static advance injection angle changing. The start of a combustion and the end of the ignition delay is defined on the basis of measurements of an in-cylinder pressure and its point of separation from a skip-fire pressure trace. The developed correlation gives better prediction of the ignition delay definition for the M-type direct injection diesel engine in the case of diesel and biodiesel fuel use when compared with the classic expression by the other authors available in the literature.
Keywords: ignition delay, diesel engine, M-type, biodiesel
Published: 31.05.2012; Views: 1276; Downloads: 294
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