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1.
Influence of biodiesel on injection, fuel spray, and engine characteristics
Breda 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: 31.05.2012; Ogledov: 999; Prenosov: 148
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2.
Experimental investigation of optimal timing of the Diesel engine injection pump using biodiesel fuel
Breda Kegl, 2006, izvirni znanstveni članek

Opis: This paper discusses the influence of biodiesel on output characteristics of adiesel engine and optimal timing setup for its injection pump. The influence of biodiesel is studied by running experiments on an NA diesel bus engine MAN D2 2566 with a direct-injection M system. The fuel used is biodiesel produced from rapeseed. Special attention is focused on the determination of the optimal injection-pump timing with respect to engine harmful emissions, enginefuel consumption, and other engine performance parameters. These engine characteristics are compared against those obtained using conventional D2 diesel. Experiments with biodiesel and D2 are run on several engine operating regimes. The engine was monitored for possible operation problems and carefully examined after the tests. The results obtained are presented and analyzed. It is shown that with carefully optimized timing of the pump, the harmful emission of NOx, smoke, HC, and CO can be reduced essentially by keeping other engine characteristics within acceptable limits.
Ključne besede: internal combustion engines, diesel engines, fuel injection, biodiesel fuel, engine characeristics
Objavljeno: 31.05.2012; Ogledov: 1251; Prenosov: 43
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3.
Numerical analysis of injection characteristics using biodiesel fuel
Breda Kegl, 2006, izvirni znanstveni članek

Opis: This paper deals with numerical analysis of injection process using biodieselžmineral diesel fuel blends with the aim to search for the potentialsto reduce engine harmful emissions. The considered fuels are neat biodiesel from rapeseed oil and its blends with mineral diesel D2. For the numerical analysis a one-dimensional mathematical model is employed. In order to model accurately the investigated fuels, the employed empirical expressionsfor their properties are determined by experiments. To verify the mathematical model and the empirical expressions, experiments and numerical simulation are run on a mechanical control diesel fuel injection M system at several operating regimes. Injection process at many different operating regimes and using several fuel blends are then investigated numerically. Attention is focused on the injection characteristics, especially on fuelling,fuelling at some stage of injection, mean injection rate, mean injection pressure, injection delay and injection timing, which influence the most important engine characteristics. The analysis of the obtained results reveals that, while keeping engine performance within acceptable limits, harmful emissions can be reduced by adjusting appropriately pump injection timing in dependence on the biodiesel content. This prediction is also confirmed experimentally.
Ključne besede: internal combustion engines, Diesel engines, fuel injection, biodiesel fuel, numerical simulation, emission reduction
Objavljeno: 31.05.2012; Ogledov: 1098; Prenosov: 53
URL Povezava na celotno besedilo

4.
Experimental analysis of injection characteristics using biodiesel fuel
Breda Kegl, Aleš Hribernik, 2006, izvirni znanstveni članek

Opis: This paper deals with injection characteristics using different fuels at different fuel temperatures. The fuels under consideration are neat biodiesel from rapeseed oil and some blends with diesel as well as neat mineral diesel D2. The fuel and fuel temperature influences are investigated experimentally in the mechanically controlled diesel fuel injection M system. At first, attention is focused on the injection characteristics, especially on fuelling, mean injection rate, mean injection pressure, injection timing, injection delay, and injection duration, which influence the most important engine characteristics. Furthermore, the influence of fuel temperature is investigated. On the basis of the measurements of pressure drop through the fuel filter, the minimum fuel temperature for safe engine operation is determined.
Ključne besede: internal combustion engines, fuel blends, biodiesel fuel, temperature influence, injection characteristics
Objavljeno: 31.05.2012; Ogledov: 989; Prenosov: 34
URL Povezava na celotno besedilo

5.
Influence of biodiesel fuel on the combustion and emission formation in a direct injection (DI) Diesel engine
Aleš Hribernik, Breda Kegl, 2007, izvirni znanstveni članek

Opis: This paper studies the influence of biodiesel fuel on the combustion and emission formation of two different direct-injected diesel engines, both employing different combustion processes. The research was focused on determining the influence of the specific combustion process on measurement results to ascertain if a generalization of the results is possible or whetherthey have to be interpreted as specific for specific engines. Standard D2 diesel fuel and commercial 100% biodiesel fuel were used. Tests were executed using both fuels under the same conditions, and exhaust emissions andengine performance were measured and compared. In-cylinder pressure was also acquired, and the rate of heat release curves were computed by means of azero-dimensional, one-zone combustion model. Some macroparameters of the combustion process were obtained from the heat-release-rate curves. The results obtained for both engines showed that findings regarding the influenceof biodiesel fuel on the combustion process and emission formation could not be generalized and had to be interpreted as specific for the particular engine.
Ključne besede: internal combustion engines, diesel engines, biodiesel fuel, combustion, emissions
Objavljeno: 31.05.2012; Ogledov: 979; Prenosov: 39
URL Povezava na celotno besedilo

6.
NOx and particulate matter (PM) emission reduction potential by biodiesel usage
Breda Kegl, 2007, izvirni znanstveni članek

Opis: The transport in many countries is the most significant source for NOx and particulate matter (PM) emissions. Therefore, the possibility of reducing NOx and PM emissions is experimentally investigated using biodiesel and some of its blends with mineral diesel. Attention is focused on the optimal bus dieselengine adjustments for each tested fuel. The obtained engine characteristics are compared to each other by considering the 13 modes of the European stationary cycle test. The optimal injection pump timings are determined with the aim of reducing harmful emissions, while keeping other engine characteristics within acceptable limits. The optimal fuel blend is suggested, and the harmful emissions (NOx, PM, CO, unburned hydrocarbon, and smoke) reduction is estimated.
Ključne besede: internal combustion engine, NOx emissions, biodiesel fuel
Objavljeno: 31.05.2012; Ogledov: 1005; Prenosov: 27
URL Povezava na celotno besedilo

7.
Optimization of a fuel injection system for diesel and biodiesel usage
Breda Kegl, Marko Kegl, Stanislav Pehan, 2008, izvirni znanstveni članek

Opis: This paper presents an optimization procedure of a fuel injection system of a bus diesel engine. Attention is focused on the differences resulting from using two different types of fuel: diesel and biodiesel. The proposed design procedure relies on the assumption that the atomization of fuel spray influences the diesel engine performance, fuel consumption, and harmful emission significantly. As a measure of spray atomization, the Sauter mean diameter is employed and introduced into the objective function. The design problem is formulated in the form of a multiobjective optimization problem, taking into account the ESC 13 mode test for diesel engines of commercial vehicles. The design variables of the injection system are related to the shape of the cam profile, to the nozzle geometry, and to the control parameters influencing the injection quantity and timing. The geometrical properties of the cam profile and the injection parameters are kept within acceptable limits by the imposed constraints. The results of optimization using diesel and biodiesel are compared to each other to show the influence offuel type on final design and performance of the system.
Ključne besede: fuel injection system, diesel engine, biodiesel fuel, engine performance, numerical simulations
Objavljeno: 31.05.2012; Ogledov: 1186; Prenosov: 36
URL Povezava na celotno besedilo

8.
Diesel and biodiesel fuel spray simulations
Primož Pogorevc, Breda Kegl, Leopold Škerget, 2008, izvirni znanstveni članek

Opis: This paper deals with the investigation of the influential parameters of a mathematical spray breakup model using different fuels. Beside injection system measurements, fuel physical properties and injection process characteristics were measured, because they are necessary for the spray simulation input. For validation purposes, spray was injected into motionless air at atmospheric pressure and room temperature and filmed with a high-speed camera. Spray macrocharacteristics have been determined on the recorded images. Using the simulation program, the injection processes for diesel, biodiesel, and their 50% blend B50 have been simulated. Spray mathematical model parameters were tuned based on the experimentally gained results. Primary breakup model parameters showed the biggest impact on the spray characteristics and were therefore expressed using the fuel physical properties, the injection process characteristics, and the working regime parameters. Spray simulations into the combustion chamber were made in the end. All of these results are presented and discussed in this paper.
Ključne besede: fuel spray, spray breakup, biodiesel fuel, fuels, numerical simulations, mathematical model
Objavljeno: 31.05.2012; Ogledov: 897; Prenosov: 44
URL Povezava na celotno besedilo

9.
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, 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: 31.05.2012; Ogledov: 765; Prenosov: 0

10.
Biodiesel usage at low temperature
Breda Kegl, 2008, izvirni znanstveni članek

Ključne besede: internal combustion engines, buses, biodiesel fuel, rapeseed oil, fuel injection system, low temperatures
Objavljeno: 01.06.2012; Ogledov: 808; Prenosov: 55
URL Povezava na celotno besedilo

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