1. Methodology improvements to simulate performance and emissions of engine transient cycles from stationary operating modes: A case study applied to biofuelsFernando Cruz-Peragón, Eloisa Torres Jiménez, Luka Lešnik, Octavio Armas, 2022, izvirni znanstveni članek Opis: In the present study engine/vehicle responses from a standardized transient test cycle are estimated using 13 stationary operating regimes following a previously developed methodology. The main advantage of the methodology tested is that allows obtaining an estimation of transient parameters in a stationary test bench, which requirements are much less demanding than those of the transient test bench. The objectives are: in one hand, to demonstrate that the methodology correctly estimates engine responses regardless of the fuel tested, as it is proposed in a previous paper and, on the other hand, to improve the methodology and the accuracy of the estimated parameters. The fuels tested are renewable fuels from different raw materials (biodiesel from rapeseed, sunflower, and soybean), and diesel fuel as the reference. Biodiesels were tested neat and blended (30% v/v) with diesel fuel. The engine is a common-rail light-duty one, and the standardized testing procedure used to illustrate the implementation of the methodology is the New European Driving Cycle (NEDC). Two design of experiments (DoE) of 13 runs each were analyzed. One of the DoE tested was proposed for characterizing the NEDC, referred as to CTDoE design, while the other one is a five-level fractional factorial design (FFDoE) that adequately matches the optimality criteria of orthogonality, D-optimal criterion, rotatability, and space-filling. The original methodology was improved by the implementation of a new fitting function that simulates the cold start effect over the engine parameters and by an new definition of the boundary in the [n,M] domain. These improvements showed significantly higher accuracy of the estimated engine parameters obtained, both instantaneous and accumulated, respect to the original methodology. The results obtained based on the application of the FFDoE design support the feasibility of the methodology tested. Engine performance and regulated emissions responses, such as intake air and fuel mass flow rate, thermomechanical exergy rate, exhaust gas residual heat rate, total hydrocarbons (THC), nitrogen oxides (NOx), carbon monoxide (CO) and particulate matter (PM) emissions from a transient test were instantaneously and cumulatively predicted with high accuracy using the engine responses from 13 steady-state operating modes. Ključne besede: simulation, light duty diesel engine, transient cycle, biodiesel, design of experiments, cold start correction function Objavljeno v DKUM: 21.09.2023; Ogledov: 350; Prenosov: 24 Celotno besedilo (13,39 MB) Gradivo ima več datotek! Več... |
2. Determining the speed of sound, density and bulk modulus of rapeseed oil, biodiesel and diesel fuelBoban Nikolić, Breda Kegl, Saša Marković, Melanija Mitrović, 2012, izvirni znanstveni članek Opis: 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. Ključne besede: biodiesel, rapeseed oil, speed of sound, bulk modulus, density, high pressure Objavljeno v DKUM: 07.07.2017; Ogledov: 1258; Prenosov: 366 Celotno besedilo (405,37 KB) Gradivo ima več datotek! Več... |
3. Uporaba alternativnih virov energije v prometuBlaž Jaklič, 2012, diplomsko delo Opis: 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. Ključne besede: plin, alternativni viri energije, bioetanol, biodiesel, vozila na vodik, električna vozila Objavljeno v DKUM: 27.10.2012; Ogledov: 2705; Prenosov: 283 Celotno besedilo (1,61 MB) |
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5. Effects of biodiesel on emissions of a bus diesel engineBreda Kegl, 2008, izvirni znanstveni članek Opis: 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. Ključne besede: biodiesel, bus diesel engine, emissions Objavljeno v DKUM: 01.06.2012; Ogledov: 1452; Prenosov: 88 Povezava na celotno besedilo |
6. Biodiesel influence on tribology characteristics of a diesel engineStanislav Pehan, Marta Svoljšak, Marko Kegl, Breda Kegl, 2009, izvirni znanstveni članek Opis: 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. Ključne besede: biodiesel, surface roughness, carbon deposits Objavljeno v DKUM: 01.06.2012; Ogledov: 2459; Prenosov: 94 Povezava na celotno besedilo |
7. Comparative study of various renewable fuels blends to run a diesel power plantEloisa Torres Jiménez, Marta Svoljšak, Andreja Gregorc, M. P. Dorado, Breda Kegl, 2010, objavljeni znanstveni prispevek na konferenci Opis: 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. Ključne besede: alternative fuel, biodiesel, bioethanol, heat engines, fuels blend Objavljeno v DKUM: 31.05.2012; Ogledov: 2554; Prenosov: 0 |
8. Comparative study of various renewable fuels blends to run a diesel power plantEloisa Torres Jiménez, Marta Svoljšak, Andreja Gregorc, M. P. Dorado, Breda Kegl, 2010, objavljeni znanstveni prispevek na konferenci Opis: 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. Ključne besede: alternative fuels, biodiesel, bioethanol, heat engines, fuels blend Objavljeno v DKUM: 31.05.2012; Ogledov: 2328; Prenosov: 0 |
9. Influence of biodiesel on injection, fuel spray, and engine characteristicsBreda Kegl, Stanislav Pehan, 2008, izvirni znanstveni članek Opis: 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. Ključne besede: biodiesel, diesel engine, injection characteristics, fuel spray, emission, lubrication Objavljeno v DKUM: 31.05.2012; Ogledov: 1954; Prenosov: 396 Celotno besedilo (1,50 MB) Gradivo ima več datotek! Več... |
10. Heat integration between two biodiesel processes using a simple methodAnita Kovač Kralj, 2008, izvirni znanstveni članek Opis: 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. Ključne besede: chemical processing, biodiesel producing, heat integration, nonlinear programming Objavljeno v DKUM: 31.05.2012; Ogledov: 2168; Prenosov: 130 Povezava na celotno besedilo |