1. Experimental investigation review of biodiesel usage in bus diesel engineBreda Kegl, Marko Kegl, 2017, izvirni znanstveni članek Opis: This paper assembles and analyses extensive experimental research work conducted for several years in relation to biodiesel usage in a MAN bus Diesel engine with M injection system. At first the most important properties of the actually used neat rapeseed biodiesel fuel and its blends with mineral diesel are discussed and compared to that of mineral diesel. Then the injection, fuel spray, and engine characteristics for various considered fuel blends are compared at various ambient conditions, with special emphasis on the influence of low temperature on fueling. Furthermore, for each tested fuel the optimal injection pump timing is determined. The obtained optimal injection pump timings for individual fuels are then used to determine and discuss the most important injection and combustion characteristics, engine performance, as well as the emission, economy, and tribology characteristics of the engine at all modes of emission test cycles test. The results show that for each tested fuel it is possible to find the optimized injection pump timing, which enables acceptable engine characteristics at all modes of the emission test cycles test.
Ključne besede: bus diesel engine, fuel injection, fuel spray, combustion, emission, engine performance, tribology characteristics, optimized injection pump timing
Objavljeno v DKUM: 07.07.2017; Ogledov: 1657; Prenosov: 417
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4. Coupled simulations of nozzle flow, primary fuel jet breakup, and spray formationEberhard von Berg, Wilfried Edelbauer, Aleš Alajbegović, Reinhard Tatschl, Martin Volmajer, Breda Kegl, Lionel C. Ganippa, 2005, izvirni znanstveni članek Opis: Presented are two approaches for coupled simulations of the injector flow withspray formation. In the first approach the two-fluid model is used within the injector for the cavitating flow. A primary breakup model is then applied at the nozzle orifice where it is coupled with the standard discrete droplet model. In the second approach the Eulerian multi-fluid model is applied for both the nozzle and spray regions. The developed primary breakup model, used in both approaches, is based on locally resolved properties of the cavitating nozzle flow across the orifice cross section. The model provides the initial droplet size and velocity distribution for the droplet parcels released from the surface of a coherent liquid core. The major feature of the predictions obtained with the model is a remarkable asymmetry of the spray. This asymmetryis in agreement with the recent observations at Chalmers University where they performed experiments using a transparent model scaled-up injector.The described model has been implemented into AVL FIRE computational fluid dynamics code which was used to obtain all the presented results.
Ključne besede: internal combustion engines, fuel injection, simulations
Objavljeno v DKUM: 01.06.2012; Ogledov: 1779; Prenosov: 95
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5. 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
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6. Optimization of a fuel injection system for diesel and biodiesel usageBreda 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 v DKUM: 31.05.2012; Ogledov: 2544; Prenosov: 92
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7. Experimental analysis of injection characteristics using biodiesel fuelBreda 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 v DKUM: 31.05.2012; Ogledov: 1840; Prenosov: 106
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8. Numerical analysis of injection characteristics using biodiesel fuelBreda 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 v DKUM: 31.05.2012; Ogledov: 2488; Prenosov: 94
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9. Experimental investigation of optimal timing of the Diesel engine injection pump using biodiesel fuelBreda 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 v DKUM: 31.05.2012; Ogledov: 2898; Prenosov: 189
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