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The Global ETD Search service is a free service for researchers
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Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
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Showing 31 to 36 of 36 (0.035 seconds)| 31 |
Weight Estimation through Frequency AnalysisJohansson, Hampus, Höglund, Nicklas January 2009 (has links)
The weight of a heavy duty vehicle plays an important role when dealing with different control systems. Examples of control units in a truck that need this parameter are the ones used to control the brakes, the engine and the gearbox. An accurate estimation of the weight leads not only to a more fuel efficient and safer transport, but also assures the driver that current law limits are not exceeded. The weight can be estimated with pretty good accuracy if the truck is equipped with air suspension. In trucks that lack this type of suspension other methods are used to estimate the weight. At present these methods are inaccurate. In this thesis a new method where the weight is to be estimated through frequency analysis of the truck's driveline is developed and evaluated.
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Internal Combustion Engine Cold Test Driveline Modeling, Analysis and DevelopmentTailony, Rauf January 2019 (has links)
No description available.
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Model-Based Approach for Resilient Vehicle OperationShveta Dhamankar (16709415) 31 July 2023 (has links)
<p>The vehicle industry has an endless appetite to get better. Often, this appetite is justified by the need of the hour. In the agricultural space, this translates to improving agricultural productivity in the face of population growth, reduced arable land and shortage of skilled farm labor. As for torsional vibrations, which have been around ever since the wheel was invented, the problem gets redefined with new regulations demanding new powertrains with improved fuel efficiency and reduced emissions.</p><p>A solution to the agriculture problem, involves efficiently automating the harvesting process.The first section of this thesis covers the ‘Auto-Unload’ where the goal of automation is achieved. This was done by building a simulation framework that was used to develop and synthesize the ‘AutoUnload’ controller. This controller was later deployed on a combine and a successful unloading on-the-go was demonstrated with a combine, tractor, and tractor-driven grain cart.</p><p>The solution to the second problem about drivetrain vibrations involved deriving a mathematical model for simulating the powertrain of a medium-duty truck. This was done to confirm resonance seen during testing done on a chassis dynamometer. The consequent control strategy to mitigate undesired vibration was to move the torque excitation away from the natural frequency of the system. This was achieved by a ‘gear-shifting’ algorithm. Comparison between on-road tests with and without the ‘gear-shifting’ algorithm showed that such a control strategy can effectively eliminate resonance. The solution methodology developed in this work is robust and transferable to higher engine torques and harvest speeds.</p>
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Val av elektrisk motor till separat drivet kraftuttag för tunga fordon / Selection of Electric Motor To Separately Driven Power Take-Off For Heavy VehicleSjöblom, Simon, Tidblom, Gustav January 2021 (has links)
I en tid kännetecknat av en strävan efter ett mer hållbart samhälle, med utformade långsiktiga klimatmål för förnyelsebara energikällor och minskade utsläpp, arbetar fordonsutvecklare med att ta fram alternativ till förbränningsmotorer. För att nå satta klimatmål och samtidigt förbättra arbetsmiljön med minskat buller anses en elektrisk drivlina som ett troligt alternativ. För tunga fordon såsom lastbilar som ofta utrustas med tillsatsutrustning som kranar, tippbara flak eller cementroterare är beroende av ett kraftuttag för att driva hydraulpumpar och generatorer. Vid en omställning till elektrisk drivlina är det inte längre säkert att möjligheten kvarstår att ta kraft från drivlinan. Detta har lett till en efterfrågan på elektriskt separat drivna kraftuttag uppstått på marknaden. Syftet med denna studie är att undersöka och få en förståelse för inom vilket effektområde och vilken typ av elektrisk motor som är bäst lämpad för att separat driva ett kraftuttag. Målet är att med denna kunskap utveckla en modell som förenklar valet av lämplig elektrisk motor för ett givet fall av kraftuttag. Modellen testas med en effekt på 60 kW vilket resulterade i att en lågvarvig axial flux BLDC-motor anses bäst lämpad. Detta då en lågvarvig elektrisk motor kräver lägre utväxling för att uppfylla krävt vridmoment, vilket ger en lägre totalvikt. Totalvikt för testad effekt hamnar på 78,6 kg, vilket är tre gånger det funktionella kravet. Studien ger en indikation på att det med givna krav enbart är försvarbart att driva kraftuttag med separata elektriska motorer vid låga effekter, runt 10 kW. / In a time characterized by an endeavor for a more sustainable society. With formulated long-term climate targets for renewable energy sources and reduced emissions, vehicle developers are working to develop alternatives to internal combustion engines. In order to achieve set climate targets and at the same time improve the working environment with reduced noise, an electric driveline is considered a likely alternative. For heavy vehicles such as trucks that are often equipped with auxiliary accessories such as cranes, tipper trucks or cement rotators are dependent on a power take-off to drive hydraulic pumps and generators. When switching to an electric driveline, it is no longer certain that the possibility remains to take power from the driveline. This has led to a demand for electrically driven power take-offs on the market. The purpose of this study is to investigate and gain an understanding of the power range and type of electric motor that is best suited to drive a power take-off separately. The goal is to use this knowledge to develop a model that simplifies the choice of a suitable electric motor for a given case of power take-off. The model is tested with an output of 60 kW, which resulted in a low-speed axial flux BLDC-motor being considered best suited. This is because a low-speed electrical motor requires a lower gear ratio to meet the required torque, which gives a lower total weight. The total weight for the tested effect ends up at 78,8 kg, which is three times the functional requirement. The study gives an indication that with given requirements it is only justified to operate power take-offs with separate electric motors at low powers, around 10 kW.
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3D Printed Lattice Structure for Driveline ApplicationsXue, Boyu January 2021 (has links)
Lattice structures have received a lot of attention as cellular materials in recent years because of their outstanding properties, such as high strength-to-weight ratio, heat transfer, energy absorption, and capability of improving noise, vibration and harshness (NVH) behavior. This type of structure received a boost from additive manufacturing (AM) technology, which can fabricate geometries in practically any shape. Due to economic and environmental requirements, lightweight design is increasingly used in automobile and construction equipment applications. NVH behavior is a crucial issue for construction equipment. However, the conventional structures' NVH behavior is mainly decided by the mass, so silence often requires heavy systems, leading to more energy consumption and emission. Therefore, the environmental trends and the resulting economic competition have limited traditional (heavy) solutions to improve NVH behavior and make the lightweight design more difficult. Novel solutions are necessary to light the difficulty and challenge of combining NVH and lightweight requirements. In this research, topology optimization was implemented on a New Articulated Hauler Transmission (NAHT) component to balance lightweight and NVH behavior. The topology- optimized 3D model was filled by a non-homogenous lattice structure with optimal lattice density via size optimization. Lattice structure optimization is one type of topology optimization, and it is the term for describing these procedures. To fabricate the complicated lattice structure, additive manufacturing (or 3D printing) is required (after topology and lattice structure optimization). The new models were analyzed using the finite element method (FEM), and the results of the analysis were compared with those of the original models. After the comparison, positive results were obtained, demonstrating that topology and lattice optimization can be applied in the design of construction equipment components. According to the results, lattice structure optimization can create a reliable lightweight design with good NVH behavior. Furthermore, lattice structure's organization and layout have a significant impact on the overall performance. / Gitterstrukturer har fått mycket uppmärksamhet som cellulära material under de senaste åren på grund av deras enastående egenskaper, t.ex. hög hållfasthet i förhållande till vikt, värmeöverföring, energiabsorption och förmåga att förbättra buller-, vibrations- och bullerskador (NVH-beteende). Denna typ av struktur har fått ett uppsving av tekniken för additiv tillverkning (AM), som kan tillverka geometrier i praktiskt taget vilken form som helst. På grund av ekonomiska och miljömässiga krav används lättviktsdesign i allt större utsträckning inom bilindustrin och byggnadsutrustning. NVH-egenskaperna är en viktig fråga för anläggningsutrustning. De konventionella konstruktionernas NVH-beteende bestäms dock huvudsakligen av massan, vilket innebär att tystnad ofta kräver tunga system, vilket leder till ökad energiförbrukning och större utsläpp. Miljötrenderna och den ekonomiska konkurrens som följer av detta har därför begränsat de traditionella (tunga) lösningarna för att förbättra NVH-egenskaperna och gjort lättviktsdesignen svårare. Nya lösningar är nödvändiga för att lösa svårigheten och utmaningen med att kombinera NVH- och lättviktskrav. I den här forskningen genomfördes topologioptimering på en komponent för en ny ledad transportörtransmission (NAHT) för att balansera lättvikts- och NVH-beteende. Den topologioptimerade 3D-modellen fylldes med en icke-homogen gitterstruktur med optimal gittertäthet via storleksoptimering. Gitterstrukturoptimering är en typ av topologioptimering, och det är termen för att beskriva dessa förfaranden. För att tillverka den komplicerade gitterstrukturen krävs additiv tillverkning (eller 3D-utskrift) (efter topologi- och gitterstrukturoptimering). De nya modellerna analyserades med hjälp av finita elementmetoden (FEM), och resultaten av analysen jämfördes med resultaten av de ursprungliga modellerna. Efter jämförelsen erhölls positiva resultat, vilket visar att optimering av topologi och gitterstruktur kan tillämpas vid utformning av komponenter för byggutrustning. Enligt resultaten kan optimering av gitterstrukturen skapa en tillförlitlig lättviktsdesign med bra NVH-beteende. Dessutom har gitterstrukturens organisering och layout en betydande inverkan på den totala prestandan.
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Minimization of Noise and Vibration Related to Driveline Imbalance using Robust Design ProcessesAl-Shubailat, Omar 17 August 2013 (has links)
Variation in vehicle noise, vibration and harshness (NVH) response can be caused by variability in design (e.g. tolerance), material, manufacturing, or other sources of variation. Such variation in the vehicle response causes a higher percentage of produced vehicles to have higher levels (out of specifications) of NVH leading to higher number of warranty claims and loss of customer satisfaction, which are proven costly. Measures must be taken to ensure less warranty claims and higher levels of customer satisfactions. As a result, original equipment manufacturers (OEMs) have implemented design for variation in the design process to secure an acceptable (or within specification) response. The focus here will be on aspects of design variations that should be considered in the design process of drivelines. Variations due to imbalance in rotating components can be unavoidable or costly to control. Some of the major components in the vehicle that are known to have imbalance and traditionally cause NVH issues and concerns include the crankshaft, the drivetrain components (transmission, driveline, half shafts, etc.), and wheels. The purpose is to assess NVH as a result of driveline imbalance variations and develop a tool to help design a more robust system to such variations.
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