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Knock mitigation study on alternative fuel heavy duty engines
(2024) Katsikioti, Dimitra; Chalmers tekniska högskola / Institutionen för mekanik och maritima vetenskaper; Chalmers University of Technology / Department of Mechanics and Maritime Sciences; Dahlander, Petter; Hansson, Axel
With increasingly stricter emissions regulations and a growing demand for higher efficiency, alternative fuels are becoming more viable alternatives to fossil fuels. Methane, for example, can be used in conventional combustion engines with minimal modifications, meeting lower emission targets. However, engines running on alternative fuels still face issues common to conventional engines, such as “knock,” which limits their efficiency. This thesis investigates the manifestation of knock in alternative fuel engines and proposes a method to prevent it while maintaining high efficiency. The method utilizes Model Predictive Control (MPC) and Artificial Neural Networks (ANNs). A detailed outline of the proposed controller is provided, along with the rationale behind its key structural characteristics. The use of ANNs to model the system’s state is also explored and evaluated. The controller is tested under various operating conditions and tuning settings to verify its effectiveness and identify optimal tuning. The proposed control method performed well in the selected cases and setup. Further improvements to both the controller and neural network structure are suggested to enhance performance. This thesis establishes that MPC can improve engine performance and prevent unfavorable operating conditions. Initially useful for engine mapping, the controller has future potential for direct implementation on the ECU.
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På banan mot en hållbar destination; en fallstudie om värdeskapandeprocessen och hållbarhetsarbetet inom evenemangsindustrin
(2024) Ekholm, Kahrin; Mauritzson, Albert; Chalmers tekniska högskola / Institutionen för arkitektur och samhällsbyggnadsteknik (ACE); Chalmers tekniska högskola / Institutionen för arkitektur och samhällsbyggnadsteknik (ACE); Strid, Marie; Strid, Marie
Denna rapport behandlar Scandinavian Touring Car Championships, STCCs, stadsrace i Göteborg 2024. Rapporten utgörs av en fallstudie som undersöker drivkrafterna för att anordna stadsevenemang och deras påverkan på värdeskapande för involverade parter. Vi tillämpade en kvalitativ undersökningsstrategi och vår undersökningsmetod baserades på dokumentära källor i form av artiklar, dokument och tidigare studier inom ämnesområdet. Tillsammans med litteratursökningar fördes semistrukturerade kvalitativa intervjuer med nyckelpersoner som var involverade i arrangerandet av evenemanget. Syftet med studien är att samla information om hur hållbarhetsarbetet under planeringsstadiet för evenemang i stadens centrum kan påverka värdeskapandet för staden och arrangören. Hållbarhet utgör en central del av all framtida utveckling, och motorsporter måste bidra till att hitta en lösning för klimatkrisen (FIA, 2024). Göteborg är en stad som ligger i framkant med hållbarhetsarbetet och har utnämnts till världens hållbaraste stad (Göteborg & Co, 2024a). Som värdstad för världens första helt elektriska nationella racingtävling har både Göteborg och STCC möjligheten att marknadsföra sig globalt. Genom att arrangera ett lyckat evenemang kan de bidra till att skapa ett värde för både staden, arrangören och deras partners. Rapporten analyserar fördelar och nackdelar när man arrangerar stora evenemang i stadens centrum med ett fokus på hållbarhet. Rapporten undersöker drivkrafterna som ligger till grund för evenemanget med betoning på att skapa ett lyckat och hållbart evenemang genom strategisk planering och samarbete. Den djupgående information som samlats in från intervjuerna presenteras med en teori om de inblandade nyckelpartnernas främsta drivkrafter och hur det påverkar det värde som evenemanget skapar för staden och arrangören. Vi diskuterar hur klimatarbetet kan skapa ett intresse hos företag att medverka i evenemanget för att använda det som strategisk marknadsföring. Arbetet är relevant för företag som är involverade i evenemangsbranschen, samt för Göteborg och andra städer.
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Neural Network-based study on background for the Dark Leptonic Scalar model at NA64
(2024) Zaya, Emil; Chalmers tekniska högskola / Institutionen för fysik; Chalmers University of Technology / Department of Physics; Cederwall, Martin; Crivelli, Paolo
The search for a particle candidate that could explain the origin of dark matter is a central goal in modern astro-particle physics. Numerous experiments employing various measurement strategies are being developed to try and understand this elusive phenomenon. The NA64 experiment situated at the north area of CERN, utilizing the CERN Super Proton Synchrotron (SPS), is an active target experiment aiming to look for signatures like missing energies with hopes of finding signals that correspond to Dark Matter (DM) particles. These dark particles are modelled to explain the physical process of kinetic mixing between the Standard Model (SM) and the hypothesised corresponding Dark Sector (DS). The main purpose of this project is to study the background for a Dark Leptonic Scalar model (DLS) using a highly accurate Monte Carlo simulation for the NA64 experiment. More precisely, the GEANT4 particle simulator was used for the NA64 experiment to simulate the results of the experimental setup used in 2023. The results of this was compared with real data taken in 2023, and a first step was benchmarking the simulation which was done by using dimuon (μμ) events. Furthermore, the simulation results were used as a means of perfecting the methods of event selection. The main source of background for DLS particle φ are μμ production, kaon κ and pion π decay. The main purpose of this thesis is to produce a trained Neural Network (NN) model that can be used for optimizing the selection of events. The background for the DLS φ was simulated and trained on a NN for selecting μμ events as a means of benchmarking the method. The selection of μμ using a trained NN is compared to traditional methods of selection, where an increase of 36 % of the final state events is seen with the NN selected data. A future study could be to simulate the DLS φ particles and train them on a NN to use for event selection. The hopes are to gain a higher signal-to-background ratio and a larger amount of data for the DLS model.
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Active Thermal Control of Power Semiconductor for High Power Electric Drive Applications
(2024) Yesgat, Amare; Chalmers tekniska högskola / Institutionen för elektroteknik; Liu, Yujing; Sharma, Nimananda
Abstract Electric vehicle applications, driven by the need for space and mass savings, increasingly demand high-power density inverters. However, this reduction in mass has led to a decrease in thermal capacity, badly exposing power emiconductors to larger temperature swings and thermal cyclic stress. The vulnerability of wire bonds and chip solder in the power semiconductor to failure due to thermal cycling necessitates a solution. This solution, actively controlling the junction temperature during operation, is the focus of this research and is referred to as active thermal control techniques (ATC). Different active thermal control strategies are explored in the literature via manipulation of losses or heat dissipation and they are discussed in this work. Some of the methods require specific hardware, such as specialized gate drivers. The control of junction temperature without any extra hardware can be achieved by controlling the PWM frequency, load current, and modulation methods. However, controlling load current requires implementing an online current reference estimation. Additionally, changing the modulation method would increase control complexity. Therefore, this work investigates active junction temperature control by varying the PWM frequency. The junction temperature is controlled using a hysteresis band-type controller with some modifications. The influence of the control band and average junction temperature calculation on the inverter’s control effectiveness, prolonged lifetime, and improved efficiency is investigated. The inverter’s losses are calculated analytically, and the inverter is implemented together with a heavy-duty truck and machine model in simulations. Drive cycle-based analysis is combined together with rain flow counting and a lifetime model to estimate the influence of the controller on the devices’ lifetime. Simulation results show that the active control of the junction temperature can result in more than 246% increase in lifetime and simultaneously increase efficiency by 0.30%.
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Utveckling av 3D-printad funktionsmodell av flygmotor
(2024) Brink, Lina; Christensson, Felix; Hemå, Petter; Karlsson, Fabian; Lundkvist, Vera; Wäpling, Alfred; Chalmers tekniska högskola / Institutionen för industri- och materialvetenskap; Chalmers University of Technology / Department of Industrial and Materials Science; Isaksson, Ola; Martinsson Bonde, Julian
In today’s society the environment has gained much attention, causing more and stricter regulations to be set regularly regarding aircrafts and their fuels. Emissions need to be minimized while transports need to get longer and faster. That is why this area is under continuous development, requiring updated information and educational tools that can aid visualizing modern and future concepts. Physical models are required to visualise the developments made, which has therefore been one of the main goals of this project to produce. A literary study has been made to collect information regarding common commersial aircrafts and fuels, as well as the most popular concepts for the near future. These concepts have then been compared and their advantages and disadvantages explored. A physical model has been created based on the information to show differences and similarities, as well as the function of different configurations of turbofan engines. This model specifically show differences regarding bypass and gears, among other things