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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    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.
51

Dvouválcový čtyřdobý plochý zážehový motor / Two-cylinder four stroke spark ignition flat engine

Dragoun, Jan January 2012 (has links)
This thesis deals with the possibilities for realization of the crankshaft-cylinder four-stroke gasoline engine is flat, usable in the urban vehicle. In the work described stresses exerted on the crank mechanism can balance the crankshaft, torsional stress and strength calculation method of control. In the final part of this work is outlined proposal for implementation of the crankshaft.
52

Dynamic Model of a Diesel Engine for Diagnosis and Balancing

Hillerborg, Per January 2005 (has links)
To monitor and control the combustion in a diesel engine one can study the speed signal from the flywheel. The idea is that if individual cylinders give different amount of torque this will lead to variations in the flywheel speed. A model which describes the cylinder torque based on flywheel speed can be used to estimate the torque from individual cylinders. With this new knowledge of the individual performance of each cylinder the engine can be balanced. The balancing aim at making the speed of the flywheel more even but also required a model with estimated cylinder torque as input. This model may also be used for testing new control algorithms easily and gaining understanding of the dynamics. In this thesis a time dissolved model is constructed to describe the cylinder pressure-, crankshaft-, flywheel and damper dynamics. The model is based on a physical point of view by approximating the system into nodes containing mass, stiffness and friction. The inputs into the model are injection data from the engine management system (EMS) and a torque from a drive line. Ways to reduce the complexity of the model are investigated in order to invert the model to estimate the injection data based on flywheel speed measurements. Measurementsare done in a test bed to receive data required for model simulation and validation. The result is that the main behavior of the dynamics is caught. The self oscillation behaviors in some operating points are however not caught which indicates that the model can not explain all behaviors. A reduced model works almost as well but of course looses more of the non stiffness behavior. As expected, the model equations can not be solved in real time. The result of the inverted reduced model depends on the flywheel signal. When the signal contains little non stiffness behavior the result is good. An observer model based on the reduced model is suggested and tested in order to estimate the indicated torque from flywheel data. The observer manages to detect errors in the injection.
53

Deformationsanalys av klämvillkor av en vevaxel / Deformation Analysis Of Clamping Conditions Of A Crankshaft

Eliasson, Fredrik, Todorovic, Ilija January 2017 (has links)
Vevaxeldeformation studeras i samband med uppspänning i en virvelfräsmaskin inför en skärande process. Syftet är att öka förståelse om deformationsbeteendet av vevaxelns viktiga funktionsytor genom analysering med Finita elementmetoden (FEM). Volvo Cars i Skövde hanterar i dagsläget oönskad vevaxeldeformation genom tidskrävande fysiska tester. Därför önskar företaget ta stöd av virtuell analysering. Detta arbete leder även till ett fastställande om FEM är ett tillämpbart verktyg att utgå ifrån för att upprätthålla snäva vevaxeltoleranser. Användning av virtuell analysering istället för fysiska tester skulle medföra tidsbesparing och ha positiv inverkan på miljön.  Programvaran Abaqus används för genomförande av deformationsanalyser vilka också utvärderas mot fysiska mätningar i en dragprovmaskin (Instron) för att därigenom säkerställa pålitligheten av använd FE modell.  Analyser genomförs huvudsakligen för deformationsuppkomst av vevaxeln i samband med uppspänning. Två olika typer av vevaxlar analyseras. Till respektive vevaxel skapas en FE modell med ansatta randvillkor och belastningsförhållanden utgående från en genomförd mekanisk analys av vevaxeln. Erhållna resultat visar att bricksidorna av vevaxeln deformeras med i storleksordningen <img src="http://www.diva-portal.org/cgi-bin/mimetex.cgi?10%5E%7B-2%7D" /> mm då vevaxeln belastas i samband med uppspänning med en hoptryckning på 0,2 mm. Denna deformation anses medföra risk att ett bearbetningsfel kan förorsakas. Analyserna visar även vilka ytor som deformeras mest/minst. Utvärdering mot dragprovning indikerar att riktning på vevaxeldeformation stämmer överens med analyserna, men att avvikelser på deformationsstorleken förekommer. Skillnaden kan möjligen förklaras med att E-modulen varierar inom den testade vevaxeln medan den definierade E-modulen i Abaqus antar ett konstant värde. Dessutom kan eventuella felkällor från dragprovningen ha inverkan på resultatutfallet av de fysiska mätningarna.  Genomförda analyser tyder på att FEM är tillämpbar för analysering av vevaxeldeformation och rekommendationer om en lämplig FE modell tillhandahålls. En potentiell lösning till deformationsproblemet anses vara beräkning av optimal klämkraft vid uppspänning. / Crankshaft deformation is studied in connection with clamping conditions in a whirl milling machine before a cutting process. The purpose of the project is to increase knowledge about the deformation behaviour of the crankshaft and its important functional surfaces by performing analyses using the finite element method (FEM). Volvo Cars in Skövde, Sweden is currently managing unwanted crankshaft deformation occurrence by using time consuming physical testing methods. Therefore, the company wish to use virtual analyses instead of physical tests. This work also leads to a determination if FEM is an applicable tool in order to maintain narrow tolerances of the crankshaft. Using virtual analyses instead of physical tests would be time saving and would also have a positive impact on the environment. The computer software Abaqus is used to implement the deformation analyses that are also evaluated against physical measurements done with a tensile testing machine (Instron) and thereby be able to ensure the reliability of the used FE model. FE analyses are mainly performed to evaluate the deformation of the crankshaft associated with clamping. Two different crankshaft types are being analysed. A FE model is created for each crankshaft along with applied boundary and load conditions according to performed mechanical analysis of the crankshaft. Obtained results show that the thrust bearing sides of the crank pins on the crankshaft deform in the range of <img src="http://www.diva-portal.org/cgi-bin/mimetex.cgi?10%5E%7B-2%7D" /> mm when the crankshaft is compressed during clamping with 0.2 mm. This deformation is considered to entail a risk for a processing error to occur. At the same time the analyses show which surfaces are most/least deformed. Evaluation according to the tensile testing indicates that the direction of the crankshaft deformation corresponds to the analysis but slight deviation of the deformation magnitude is present. The deviations can be explained by variations of the E-module within the crankshaft while the defined E-module in Abaqus has a constant value. Furthermore, there is a possibility that sources of error from the tensile tests can have an influence on the obtained results from the physical measurements. Conducted analyses indicates that FEM is applicable for crankshaft deformation analyses and recommendations of a suitable FE model are provided. A potential solution of the deformation problem is considered to be the calculation of optimal clamping force.
54

Torzní kmitání tříválcového motoru s vyvažovací hřídelí / Torsional Vibration of Three Cylinder Engine with Balancing Shaft

Jurík, Juraj January 2017 (has links)
Content of this master thesis is analysis of torsional vibration of the three cylinder engine with balancing shaft. In theoretical part of the thesis the kinematic and dynamic description of the cranktrain mechanism is included. The formation of unbalancing of the engine and methods of balancing are described in the theoretical part as well. In practical part of the thesis the analytical calculation of torsional vibration is provided. Simulation of the engine model in multibody software Adams/Engine was used as the other way of torsional vibration analysis. In the result part of the thesis the comparison of the both way of analysis were discussed. Last step of the thesis was design proposal of the torsional vibration damper done by the analytical calculation.
55

Čtyřválcový vznětový motor s vypínáním válců / Four-cylinder diesel engine with cylinder deactivation

Weidner, Lukáš January 2017 (has links)
The aim of this thesis is design crankshaft for four-cylinder diesel engine with cylinder deactivation. Further, to perform stress analysis of designed crankshaft with considering torsional vibration.
56

Čtyřválcový zážehový motor s vypínáním válců / Four-cylinder gasoline engine with cylinder deactivation

Steigl, Vladimír January 2017 (has links)
The aim of this diploma thesis is design of configuration and balancing of crankshaft which is determined for four-cylinder gasoline engine. The thesis investigates kinematics, dynamics and possible ways of balancing the inertial forces and moments of the rotating and sliding parts of the central crank mechanism. Subsequently, the 3D CAD model is designed according to the presented drawing. It is transformed into a spare torsion system, from which the calculations of its own and forced torsional vibrations are based. The proposed 3D CAD model is then spatially transmitted in the FEA software Ansys Workbench and modified (boundary conditions, etc.) in the FEA software Ansys Mechanical APDL so that it can be calculated according to the selected LSA method. From the selected results of the LSA method, the crankshaft safety factor against fatigue damage is calculated.
57

Koncepce řadového zážehového motoru / Concept of an In-line Spark-ignition Engine

Kočvara, Antonín January 2020 (has links)
This thesis deals with comparison of straight four-cylinder petrol engine with a displacement of 1,5 litres and its three-cylinder alternative, which is based on a four-cylinder. The thesis starts with a research, where are examples of some currently manufactured engines. The research is followed by design of both engines, where the design of the crank mechanisms is made more in detail. After that, both crank mechanisms are subjected to dynamic analysis using FEM and MBS methods. The thesis ends with comparison of both engines in terms of crankshaft load, mass and dimensions.
58

Modální vlastnosti klikového ústrojí čtyřválcového traktorového motoru / Modal Properties of 4-cylinder Tractor Engine Powertrain

Ehrenberger, Pavel January 2010 (has links)
This diploma thesis contains a summary of the general information about the torsion vibration of the crankshaft. The main task is to prepare a flexible model of the crankshaft in the FEM program ANSYS and the subsequent export into the MBS ADAMS / Engine. According to parameters the model of four-cylinder line tractor engine with flexible crankshaft is built. Crank mechanism is analyzed to determine the natural frequencies and natural modes. Finally the results are evaluated and compared with analytical calculations.
59

Pětiválcový řadový vznětový motor / Five-cylinder in-line diesel engine

Parchański, Martin January 2010 (has links)
The purpose of this thesis is design of in-line a five-cylinder diesel engine arrangement with given main parameters, power train design, balancing centrifugal and inertia moments and calculation of torsion vibrations. The proposed engine must be based on four-cylinder diesel Zetor engine.
60

Kogenerační jednotka se dvěma plynovými vidlicovými šestnáctiválci / Combined heat and power pack with two gas V-sixteen engines

Švancara, Jan January 2010 (has links)
Thesis deals with the calculation of the crankshaft of the cogeneration unit. It deals with the calculation of equity and forced vibration of the crankshaft. Attention is also paid to the influence of elastic couplings on the shape of its own vibration shaft.

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