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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.
1

Modelling and Validation of a Truck Cooling System

Nordlander, Erik January 2008 (has links)
<p>In the future, new challenges will occur during the product development in the vehicular industry when emission legislations getting tighter. This will also affect the truck cooling system and therefore increase needs for analysing the system at different levels of the product development. Volvo 3P wishes for these reasons to examine the possibility to use AMESim as a future 1D analysis tool. This tool can be used as a complement to existing analysis methods at Volvo 3P. It should be possible to simulate pressure, flow and heat transfer both steady state and transient.</p><p>In this thesis work a cooling system of a FH31 MD13 520hp truck with an engine driven coolant pump is studied. Further a model of the cooling system is built in AMESim together with necessary auxiliary system such as oil circuits. The model is validated using experimental data that have been produced by Volvo 3P at the Gothenburg facility.</p><p>The results from validation and other simulations show that the model gives a good picture of the cooling system. It also gives information about pressure, flow and heat transfer in steady state conditions. Further a design modification is done, showing how a change affects the flow in the cooling system.</p><p>The conclusion is that a truck cooling system can be built and simulated in AMESim. Further, it shows that AMESim meets the requirements Volvo 3P in Gothenburg has set up for the future 1D analysis tool and thereby AMESim is a good complement to the already existing analysis method.</p>
2

Modelling and Validation of a Truck Cooling System

Nordlander, Erik January 2008 (has links)
In the future, new challenges will occur during the product development in the vehicular industry when emission legislations getting tighter. This will also affect the truck cooling system and therefore increase needs for analysing the system at different levels of the product development. Volvo 3P wishes for these reasons to examine the possibility to use AMESim as a future 1D analysis tool. This tool can be used as a complement to existing analysis methods at Volvo 3P. It should be possible to simulate pressure, flow and heat transfer both steady state and transient. In this thesis work a cooling system of a FH31 MD13 520hp truck with an engine driven coolant pump is studied. Further a model of the cooling system is built in AMESim together with necessary auxiliary system such as oil circuits. The model is validated using experimental data that have been produced by Volvo 3P at the Gothenburg facility. The results from validation and other simulations show that the model gives a good picture of the cooling system. It also gives information about pressure, flow and heat transfer in steady state conditions. Further a design modification is done, showing how a change affects the flow in the cooling system. The conclusion is that a truck cooling system can be built and simulated in AMESim. Further, it shows that AMESim meets the requirements Volvo 3P in Gothenburg has set up for the future 1D analysis tool and thereby AMESim is a good complement to the already existing analysis method.
3

[en] A MANAGERIAL APPROACH TO THE GROUND VEHICLES SUSPENSION DESIGN PROCEDURE / [pt] UMA ABORDAGEM GERENCIAL PARA O PROCEDIMENTO DE PROJETO DE SUSPENSÕES DE VEÍCULOS TERRESTRES

MICHAEL CORDEIRO CARVALHO MERLING 03 April 2008 (has links)
[pt] Apresenta-se uma visão gerencial para o procedimento de projeto de suspensões de veículos terrestres. São descritos, em linhas gerais, os principais aspectos técnicos relativos ao projeto deste sub-sistema veicular, e tratados, com detalhes, os tópicos fundamentais para a sua administração. Discute-se, entre outras, as etapas de especificação do projeto, quesitos necessários, normas a serem aplicadas, e as etapas a cumprir, segundo a visão do gerente administrativo do projeto, responsável pela organização do grupo de técnicos que irá desenvolvê-lo. / [en] It is shown a managerial vision of the ground vehicles suspension design procedure. Are described, in general lines, the main technical aspects related to the design of this vehicular sub-system, and treats, with details, the fundamental topics for its administration. It is discussed, beside others, the design specification stages, necessary requirements, norms to be applied, and the stages to accomplish, according to the vision of the administrative design manager, responsible for the organization of the technicians' group that will develop it.
4

Automatic geo-referencing by integrating camera vision and inertial measurements

Randeniya, Duminda I. B 01 June 2007 (has links)
Importance of an alternative sensor system to an inertial measurement unit (IMU) is essential for intelligent land navigation systems when the vehicle travels in a GPS deprived environment. The sensor system that has to be used in updating the IMU for a reliable navigation solution has to be a passive sensor system which does not depend on any outside signal. This dissertation presents the results of an effort where position and orientation data from vision and inertial sensors are integrated. Information from a sequence of images captured by a monocular camera attached to a survey vehicle at a maximum frequency of 3 frames per second was used in upgrading the inertial system installed in the same vehicle for its inherent error accumulation. Specifically, the rotations and translations estimated from point correspondences tracked through a sequence of images were used in the integration. However, for such an effort, two types of tasks need to be performed. The first task is the calibration to estimate the intrinsic properties of the vision sensors (cameras), such as the focal length and lens distortion parameters and determination of the transformation between the camera and the inertial systems. Calibration of a two sensor system under indoor conditions does not provide an appropriate and practical transformation for use in outdoor maneuvers due to invariable differences between outdoor and indoor conditions. Also, use of custom calibration objects in outdoor operational conditions is not feasible due to larger field of view that requires relatively large calibration object sizes. Hence calibration becomes one of the critical issues particularly if the integrated system is used in Intelligent Transportation Systems applications. In order to successfully estimate the rotations and translations from vision system the calibration has to be performed prior to the integration process. The second task is the effective fusion of inertial and vision sensor systems. The automated algorithm that identifies point correspondences in images enables its use in real-time autonomous driving maneuvers. In order to verify the accuracy of the established correspondences, independent constraints such as epipolar lines and correspondence flow directions were used. Also a pre-filter was utilized to smoothen out the noise associated with the vision sensor (camera) measurements. A novel approach was used to obtain the geodetic coordinates, i.e. latitude, longitude and altitude, from the normalized translations determined from the vision sensor. Finally, the position locations based on the vision sensor was integrated with those of the inertial system in a decentralized format using a Kalman filter. The vision/inertial integrated position estimates are successfully compared with those from 1) inertial/GPS system output and 2) actual survey performed on the same roadway. This comparison demonstrates that vision can in fact be used successfully to supplement the inertial measurements during potential GPS outages. The derived intrinsic properties and the transformation between individual sensors are also verified during two separate test runs on an actual roadway section.
5

A Framework for Evaluation of Cylinder Balancing Controllers

Lindström, Niclas January 2017 (has links)
Cylinder speed variations in a combustion engine is an unwanted phenomenon caused by a number of different reasons. Inaccurate fuel delivery from the individual injectors, resonance frequencies in the drive train and faulty sensor readings are some probable causes. There is a need to investigate the potential of different cylinder balancing controllers in a simulation environment before implementing them in the ECU hardware. The thesis is about developing a simulation framework where different controllers can be tested. The framework will generate an engine speed signal based on injected fuel mass to the individual cylinders. A PI controller that makes individual fuel adjustments to the cylinders is implemented in the framework and tested for three different operating points and three different types of disturbances. The results show that the framework is able to generate an accurate engine speed signal based on the commanded fuel amount. Moreover the controller is able to eliminate imbalances caused by error in injected fuel mass as well as specific type of periodic load disturbances in the drive line. Some disturbances cannot be handled by the PI controller, as they lie outside of its controllable region. The simulation framework shows promising results and while further work is needed in some areas, it can work as a foundation for future development and controller evaluation.
6

Data-Driven Engine Fault Classification and Severity Estimation Using Residuals and Data

Lundgren, Andreas January 2020 (has links)
Recent technological advances in the automotive industry have made vehicularsystems increasingly complex in terms of both hardware and software. As thecomplexity of the systems increase, so does the complexity of efficient monitoringof these system. With increasing computational power the field of diagnosticsis becoming evermore focused on software solutions for detecting and classifyinganomalies in the supervised systems. Model-based methods utilize knowledgeabout the physical system to device nominal models of the system to detect deviations,while data-driven methods uses historical data to come to conclusionsabout the present state of the system in question. This study proposes a combinedmodel-based and data-driven diagnostic framework for fault classification,severity estimation and novelty detection. An algorithm is presented which uses a system model to generate a candidate setof residuals for the system. A subset of the residuals are then selected for eachfault using L1-regularized logistic regression. The time series training data fromthe selected residuals is labelled with fault and severity. It is then compressedusing a Gaussian parametric representation, and data from different fault modesare modelled using 1-class support vector machines. The classification of datais performed by utilizing the support vector machine description of the data inthe residual space, and the fault severity is estimated as a convex optimizationproblem of minimizing the Kullback-Leibler divergence (kld) between the newdata and training data of different fault modes and severities. The algorithm is tested with data collected from a commercial Volvo car enginein an engine test cell and the results are presented in this report. Initial testsindicate the potential of the kld for fault severity estimation and that noveltydetection performance is closely tied to the residual selection process.
7

[en] GROUND VEHICLES SUSPENSION AND STEERING MECHANISMS MODELING AND INTEGRATION THROUGH POWER FLOW / [pt] MODELAGEM E INTEGRAÇÃO DOS MECANISMOS DE SUSPENSÃO E DIREÇÃO DE VEÍCULOS TERRESTRES ATRAVÉS DO FLUXO DE POTÊNCIA

RICARDO TEIXEIRA DA COSTA NETO 27 October 2008 (has links)
[pt] A sub-divisão de um veículo em módulos é muito útil quando se quer estudar o comportamento dinâmico de um determinado subsistema e sua influência nos demais componentes. Em alguns casos, devido ao tipo de tratamento empregado para descrever os elementos, não se consegue perceber de que modo as variáveis inerentes a um subsistema interagem com as demais, e, por conseguinte, os subsistemas entre si. A abordagem modular baseada no fluxo de potência permite uma melhor identificação das relações de causa e efeito entre subsistemas, uma vez que se pode definir, de forma clara e consistente, quem são as variáveis de entrada e de saída de cada componente ou módulo, e, conseqüentemente, seus acoplamentos. Neste tipo de tratamento, aplicado aos sistemas mecânicos, uma vez estabelecida a cinemática de um subsistema, podese obter as relações entre os esforços que seus componentes produzem uns sobre os outros, a partir da caracterização da potência transmitida através dos seus diversos elementos. Este trabalho apresenta um procedimento semi-analítico de equacionamento modular aplicado à modelagem e integração dos sistemas de suspensão e direção de veículos terrestres, no qual as variáveis de entrada e saída indicam o fluxo de potência entre os elementos de todo o sistema. Tal abordagem tem como base a técnica dos Grafos de Ligação, empregada em sistemas multidomínio em geral, e usa alguns conceitos da metodologia dos Transformadores Cinemáticos, normalmente aplicada aos sistemas multicorpos. A partir da definição da geometria dos mecanismos em questão, encontram-se as matrizes que representam os vínculos cinemáticos entre seus elementos, das quais o funcionamento dos sistemas integrados pode ser simulado e analisado, e informações necessárias aos seus projetos determinadas. As equações (malhas) algébricas que existem em mecanismos com estrutura cinemática fechada são analiticamente resolvidas, evitando deste modo modelos matemáticos com equações diferenciais e algébricas simultâneas. Das relações cinemáticas, o modelo dinâmico (matrizes de inércia, rigidez e amortecimento, etc) é obtido, e novamente informações essenciais à análise e síntese dos sistemas podem ser determinadas. O comportamento no tempo desses modelos pode ser encontrado por um método de integração de equações diferenciais qualquer. Adota-se o Simulink/MatLab® para representar o modelo assim desenvolvido em diagrama de blocos, e conseqüentemente simulá-lo. Através deste tratamento, cada bloco da implementaçao em Simulink/MatLab® contém o correspondente modelo analítico de um único módulo, cujo estabelecimento depende das características dinâmicas do sistema que se deseja analisar. A vantagem de adotar tal representação, baseada no fluxo de potência, consiste no fato de que um módulo pode ser substituído por outro, descritivo de um elemento ou subsistema com a mesma função, porém com configuração física distinta, e, conseqüentemente, modelo matemático específico, sem qualquer alteração nos demais componentes do sistema. Este procedimento está sendo adotado para modelagem dos diversos sistemas veiculares, como os de suspensão, direção, transmissão e freios, e também os pneus, inseridos em um chassi, incluindo os graus de liberdade desejados do veículo, todos descritos de forma modular semi- analítica através da mesma abordagem, empregando a técnica de modelagem mais apropriada para representá-los. / [en] The sub-division of a vehicle in modules is very useful when we want to study the dynamical behavior of a certain sub-system and its influence in other components. In some cases, due to the type of treatment employed to describe the dynamic behavior of the elements, we don`t get to notice the way that inherent variables in a sub-system interacts with the others, and, consequently, the subsystems amongst themselves. The modular approach based on the power flow allows a better identification of the causal relationships among sub-systems, once it can define, in clear and consistent way, what are the input and output variables of each component or module, and, consequently, their couplings. In this type of treatment applied to the mechanical systems, once established the kinematics of a sub-system, it can be obtained the relationships among the efforts that their components produce on the other ones, from the characterization of the power transmitted through their several elements. This paper presents a semi-analytical procedure of modular modeling applied to the suspension and steering systems of a ground vehicle, in which the input and output variables indicate the power flow among the elements of the whole system. Such approach has as base the Bond Graphs technique, used in multidomain systems in general, and uses some concepts of the Kinematic Transformers methodology, usually applied to the multibody systems. From the mechanisms geometry, the matrices that represent the kinematics links between its elements are found, the operation of the integrated systems can be simulated and analyzed, and information about its design can be obtained. The algebraic loops (equations) inherent to mechanisms with closed kinematic structure are solved analytically, and there is not a mathematical model with simultaneous algebraic and differential equations. From the kinematic relations, the dynamic model (inertial, stiffness and damping matrices) is obtained, and again essential information to the systems analysis and synthesis can be determined. The models time behavior can be found by any differential equations integration method. The Simulink/Matlab is adopted to represent the model developed by block diagrams, and consequently to simulate it. Through this treatment, each block in the Simulink/Matlab implementation contains the correspondent analytical model of a single module, whose establishment depends on the dynamic characteristics of the system to be analyzed. The advantage of adopting such representation, based on the power flow, consists in the fact that a module can be substituted for other, descriptive of an element or sub-system with the same function, however with different physical configuration, and, consequently, specific mathematical model, without any alteration in the other components of the system. This procedure is being adopted for modeling all vehicular systems, like the suspension, steering, transmission and brakes systems, and also the tires, inserted in the chassis, including the desired degrees of freedom of the vehicle, all described in a semi- analytical modular way by the same approach, using the most appropriate modeling technique to represent them.

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