This diploma thesis deals with the creation a web presentation of e-commerce of a firm. It includes descriptions and analysis of the specific subject. Also it contents suggestion of electronic commerce, which should contribute to a stable position of the firm in this market, to increase awareness among customers and ultimately to increase profits. Then it describes the problems related to implementation of e-commerce and economic evaluation of the proposal for electronic commerce.

This article describes the first development phase of a centrifugal compressor with variable geometry which is designed to match the needs of future heavy-duty engines. Requirements of truck engines are analyzed, and their impact on the properties of the compressor map is evaluated in order to identify the most suitable kind of variable geometry. Our approach utilizes the transformation of engine data into pressure ratio and mass flow coordinates that can be displayed and interpreted using compressor maps. One-dimensional and three-dimensional computational fluid dynamics fluid flow calculations are used to identify loss mechanisms and constraints of fixed geometry compressors. Linking engine goals and aerodynamic objectives yields specific recommendations on the implementation of the variable geometry compressor.

Electrically powered vertical takeoff and landing (eVTOL) aircraft could provide a new mode of air transportation of people and cargo that is low-cost, on-demand, and able to reach more areas than is possible with current technology. They have the unique ability to takeoff and land in congested spaces yet efficiently travel long distances which makes them a promising technology for applications such as rapid medical assistance, automated package delivery, or human transportation. This type of aircraft has only recently become a possibility, owing to advancements in battery technology, computing power, and sensor technologies, and thus support for eVTOLs is lacking among high-fidelity graphics simulation software. High-fidelity graphics are important for the goal of fully autonomous eVTOL aircraft in order to accurately simulate vision-based navigation using camera sensors. In this work, we present VTOL-AirSim, an extension of Microsoft AirSim with full integration of a tiltrotor eVTOL aircraft. Built on Unreal Engine, a high-end graphics game engine, it includes photorealistic graphics for simulated camera images and for high-quality presentations. We created the visual components of a fully animated tiltrotor vehicle and a detailed city environment for it to fly in. The tiltrotor can be controlled via motor PWM commands, by overriding its state in the world with the use of an external dynamics simulation, or by using the PX4 Autopilot. We give a tutorial on how to use VTOL-AirSim where we provide examples for each method of control, including scripts for controlling the tiltrotor via a geometric controller and control allocation module developed by others in the BYU MAGICC Lab. We also show how to further develop VTOL-AirSim, and how to add custom aircraft or custom environments so that others may use it in their own research.

[EN] Current challenges in research and development of powertrains demand new computational tools capable of simulating vehicle operation under very diverse conditions. This is due, among other reasons, to new homologation standards in the automotive sector requiring compliance of exhaust emissions regulations under any possible driving condition on the road. Global engine or vehicle models provide many advantages to engineers because they allow to reproduce the entire system under study, considering the physical processes that take place in different components and the interactions among them. This thesis aims to enable the modeling of heat transfer processes in a complete engine simulation tool developed at CMT-Motores Térmicos research institute. This 0D/1D simulation tool is called Virtual Engine Model (VEMOD). The development of heat transfer models comprises the engine block and the ancillary systems. The model of heat transfer in the engine block deals with the central problem of in-cylinder convection by means of a combination of experimental research, CFD simulation and multizone 0D modeling. The other thermal processes present in the engine block are examined in order to implement suitable submodels. Once the model is complete, it undergoes a validation with experimental transient tests. Afterwards, the ancillary systems for engine thermal management are brought into focus. These systems are considered by means of two new models: a model of heat exchangers and a model of thermo-hydraulic circuits. The development of those models is reported in detail. Lastly, with the referred thermal models integrated in the global simulation tool, a validation study is undertaken. The goal is to validate the ability of the Virtual Engine Model to capture the thermal response of a real engine under various operating conditions. To achieve that, an experimental campaign combining tests under steady-state operation, under transient operation and at different temperatures is conducted in parallel to the corresponding simulation campaign. The capacity of the global engine simulations to replicate the measured thermal evolution is finally demonstrated. / [ES] Los retos actuales en la investigación y desarrollo de trenes de potencia demandan nuevas herramientas computacionales capaces de simular el funcionamento de un vehículo en condiciones muy diversas. Esto se debe, entre otras razones, a que los nuevos estándares de homologación en el sector de la automoción obligan al cumplimiento de las regulaciones de emisiones en cualquier condición posible de conducción en carretera. Los modelos globales de motor o de vehículo proporcionan muchas ventajas a los ingenieros porque permiten reproducir el sistema entero a estudiar, considerando los procesos físicos que tienen lugar en los distintos componentes y las interacciones entre ellos. Esta tesis pretende hacer posible el modelado de los procesos de transmisión de calor en una completa herramienta de simulación de motor desarrollada en el instituto de investigación CMT-Motores Térmicos. Esta herramienta de simulación 0D/1D se denomina Motor Virtual o Virtual Engine Model (VEMOD). El desarrollo de modelos de transmisión de calor comprende el bloque motor y los sistemas auxiliares. El modelo de transmisión de calor en el bloque motor aborda el problema central de la convección en el interior del cilindro mediante una combinación de investigación experimental, simulación CFD y modelado 0D multizona. El resto de procesos térmicos presentes en el bloque motor son examinados para poder implementar submodelos adecuados. Una vez el modelo está terminado, se realiza una validación con ensayos experimentales en régimen transitorio. A continuación, el foco de atención pasa a los sistemas auxiliares de gestión térmica. Estos sistemas se toman en consideración por medio de dos nuevos modelos: un modelo de intercambiadores de calor y un modelo de circuitos termohidráulicos. El desarrollo de los modelos se explica en detalle en esta tesis. Por último, con los citados modelos integrados en el Motor Virtual, se lleva a cabo un estudio de validación. El objectivo es validar la capacidad del Motor Virtual para reproducir la respuesta térmica de un motor real en varias condiciones de funcionamento. Para conseguirlo, se realiza una campaña experimental que combina ensayos en régimen estacionario, en régimen transitorio y a diferentes temperaturas, en paralelo a la campaña de simulación correspondiente. La capacidad de las simulaciones globales de motor para replicar la evolución térmica medida experimentalmente queda finalmente demostrada. / [CA] Els reptes actuals en la recerca i el desenvolupament de trens de potència demanden noves eines computacionals capaces de simular el funcionament d'un vehicle en condicions molt diverses. Açò es deu, entre altres raons, a que els nous estàndards d'homologació al sector de l'automoció obliguen al compliment de les regulacions d'emissions en qualsevol condició possible de conducció en carretera. Els models globals de motor o de vehicle proporcionen molts avantatges als enginyers perquè permeten reproduir el sistema sencer a estudiar, considerant els processos físics que tenen lloc als distints components i les interaccions entre ells. Aquesta tesi pretén fer possible el modelat dels processos de transmissió de calor en una completa eina de simulació de motor desenvolupada a l'institut de recerca CMT-Motores Térmicos. Aquesta eina de simulació 0D/1D s'anomena Motor Virtual o Virtual Engine Model (VEMOD). El desenvolupament de models de transmissió de calor comprén el bloc motor i els sistemes auxiliars. El model de transmissió de calor al bloc motor aborda el problema central de la convecció a l'interior del cilindre mitjançant una combinació de recerca experimental, simulació CFD i modelat 0D multizona. La resta de processos tèrmics presents al bloc motor són examinats per a poder implementar submodels adequats. Una vegada el model està acabat, es fa una validació amb assajos experimentals en règim transitori. A continuació, el focus d'atenció passa als sistemes auxiliars de gestió tèrmica. Aquests sistemes es prenen en consideració per mitjà de dos nous models: un model d'intercanviadors de calor i un model de circuits termohidràulics. El desenvolupament dels models s'explica en detall en aquesta tesi. Per últim, amb els referits models integrats al Motor Virtual, es porta a terme un estudi de validació. L'objectiu és validar la capacitat del Motor Virtual per a reproduir la resposta tèrmica d'un motor real en diverses condicions de funcionament. Per a assolir-ho, es realitza una campanya experimental que combina assajos en règim estacionari, en règim transitori i a diferents temperatures, en paral·lel a la campanya de simulació corresponent. La capacitat de les simulacions globals de motor per a replicar l'evolució tèrmica observada experimentalment queda finalment demostrada. / European funds received in the framework of Horizon 2020’s DiePeR project have contributed to the validation and improvement of the Virtual Engine Model. My own dedication has been funded by Universitat Politècnica de València through the predoctoral contract FPI-S2-2016-1357 of “Programa de Apoyo para la Investigaci´on y Desarrollo (PAID-01-16)”. / Salvador Iborra, J. (2020). A contribution to the global modeling of heat transfer processes in Diesel engines [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/149575 / TESIS

Abstract: This thesis aims to contribute to the development of the isobaric combustion engines by exploring multiple injection strategies, by means of computational simulations using a commercial software Converge. A single injection case validated with experimental data in terms pressure trace and heat release rate was used as a baseline reference. The adjustment of the turbulent kinetic energy dissipation constant is found to have the most significant influence in reproducing the pressure and heat release rate histories observed in the experiment. As a first attempt to achieve isobaric combustion, a multiple injection strategy using a single injector was explored with up to four consecutive injections. Considering that the computational simulations were unable to reproduce the experimental data due to a number of uncertainties in the implemented models, the present study attempted to identify the main causes of the discrepancies through various parametric studies. First, different liquid fuel properties were examined and it was found that, while the physical properties of the fuels have a notable effect in terms of evaporation and atomization, such variations were not sufficient to reproduce the experimentally observed heat release cycle. Next, the effects of the uncertainties in the kinetic mechanisms were assessed by the reaction multiplier, an artificial adjustment of the rate constants, and it was found that the reaction multiplier affected the ignition of the first injection, but not the subsequent injection events. As such, the use of reaction multipliers to reproduce the experimental data was found to be unsuccessful. The effect of thermodynamics properties was also examined by employing real-gas equations of state, such as Redlich-Kwong and Peng-Robinson, and the results showed little difference at the conditions under consideration. Finally, advancing the start of injection was found to have the most significant effect on pressure trace and heat release rate to lead to a substantial improvement in the numerical prediction. The results suggest that the key uncertainties in modeling of the present engine combustion are likely the accurate timing of the start of injection combined with the exact injection rate shape profile.

A joint experimental and numerical project has been initiated at Virginia Tech to study the effect of ozone on diesel soot precursors. This thesis is the first stage of the numerical part of the project, and contains a study of the effect of the different ozone levels on diesel soot precursors. This numerical study is executed via the use of two computer programs, Senkin, and PSR. An idealistic model of the diesel engine was used in both analyses. The numerical studies were done at three different engine speeds, 1500, 2000, 2500 RPM and eight different levels of ozone. Studies were performed with ozone introduced with the intake air and with the fuel. Eleven product species, which include dominant soot precursors such as acetylene (C2H2) and the propargyl radical (C3H3), were examined and evaluated during this experiment. After analyzing both simulations, the PSR predictions were not useful since it omits the existence of temperature and species gradients. The PSR analysis was used as a preliminary model to get an overall idea of combustion pollutant formation and predicted the exit soot precursor concentrations were unaffected by any ozone addition. However, the Senkin analysis predicted the ozone injection did have the potential to reduce the formation of soot precursors. The Senkin analysis predicted more realistic results and therefore it is believed to yield the correct conclusion. However, it was suggested that an additional program, such as KIVA3, be utilized to predict a more practical view of the chemical kinetic behavior of ozone and its effect on the diesel engine. / Master of Science

The goal of the present work is to develop an open architecture engine controller to operate a production model, heavy-duty diesel engine. Where OEM engine control units (ECUs) are inflexible, this controller is designed to provide the hardware and software flexibility required to facilitate dualuel combustion research. This thesis includes thorough descriptions of the hardware and software development required to interface with all engine sensors and actuators. To establish baseline control settings for the open controller, OEM ECU responses are mapped over a range of speeds and loads. This information is used to calibrate the open controller. Comparison tests considering speed, load, and emissions are performed to ensure the open controller provides a close approximation of OEM engine operation. The results of the tests confirm that the open controller provides full control of the engine with baseline settings close to those of the OEM ECU.

Current diesel technologies involve a broad spectrum of combustion regimes. Previous diesel combustion models either lack the universality across various combustion regimes or suffer computational cost. This dissertation discusses the development of a phenomenological framework to identify and understand key in-cylinder processes that influence the overall performance of a compression ignition engine. The first part of this research is focused on understanding the ignition delay (ID) of diesel fuel in a pilot-ignited partially premixed, low temperature natural gas (NG) combustion engine. Lean premixed low temperature NG combustion is achieved by using small pilot diesel sprays (2-3% of total fuel energy) injected during early compression stroke (about 60° BTDC). Modeling ignition delay at advanced pilot injection timings (50°-60°BTDC) presents unique challenges. In this study, single component droplet evaporation model in conjunction with the Shell hydrocarbon autoignition (SAI) model is used to obtain ignition delay predictions of pilot diesel over a wide range of injection timings (20°-60° BTDC). Detailed sensitivity analysis of several SAI model parameters revealed that the model parameter Aq, which influences chain initiation reactions, was most important to predict ignition delays at very lean equivalence ratios. Additional studies performed to ascertain critical model parameters revealed that ignition delay was particularly sensitive to intake manifold temperature over the range of injection timings investigated. Finally, the validated SAI model was used to predict ignition delays of pilot diesel fuel at various exhaust gas recirculation (EGR) substitutions, intake manifold temperatures and engine loads (bmep = 6 bar and 3 bar, respectively). The second part of this research involved the development of a phenomenological simulation of diesel/biodiesel combustion, which included sub-models for diesel spray entrainment, evaporation, ignition and premixed and mixing-controlled combustion. In the simulation, the cylinder contents consisted of an unburned zone, packet zones, and a burned zone. The simulation, after appropriate calibration, was capable of predicting cylinder pressure and heat release rates at different engine load conditions over the injection timing range of 0°BTDC to 10°BTDC. The total number of packets, droplet evaporation rates, air entrainment rates; ignition delay and premixed/mixing-controlled reaction rate parameters had a profound influence on combustion predictions.

This writing covers the process of lighting stylized and realistic scenes in different moods in Unreal Engine. Lighting can be used to express a mood in an environment, which can aid storytelling in films and games. Lighting in Unreal consists of positioning directional lights, sky lights, spot lights, point lights, and rect lights, as well as various fog effects that help create the ambiance of the scene. This project utilizes free Epic Games Pack content to show the lighting process for different moods in several environments. The use of lights and colors are an important part of designing a game environment which conveys moods and allows for playability.

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