This diploma thesis .deals with a crankshaft analysis of the VW 6,0 W12 engine. The first goal is to create a CAD model from the real part, then to create a FEM model for computer simulations. With respect to a dynamic character of the loading, the crankshaft is then reduced into a MNF file for the purpose of dynamic simulations in the MBS ADAMS/Engine. The full range of working RPMs is simulated in it. Beside the crankshaft the main and pin bearings are studied too. At the last part of this thesis the durability of the crankshaft is solved.

With tougher emission standards for heavy duty trucks, good control of the engine is of importance. By taking into consideration the torsional vibrations occurring in the crankshaft, the engine control can be improved. This could be done by implementing a torsion model that would give feedback to the engine control unit to reduce the cycle-to-cycle variations in the cylinders, which is partly due to the torsion in the crankshaft. It is therefore of interest to determine if a torsion model can be developed with a reduced computational complexity and still have sufficient accuracy. In this thesis a model was developed in Matlab for estimation of torsion in the crankshaft of an inline 6 cylinder diesel engine. By applying Newtons second law, the equations of motion that describe the torsional vibrations in the crankshaft were set up. The equations of motion were transformed using modal analysis and with the use of mode superposition it was investigated how reducing the number of vibrational modes in the model, affected the models accuracy in its estimation of torsion. Two model reductions were evaluated where the first three and four vibrational modes were used to calculate the torsional displacement between the flywheel and the cylinders. Using measured pressure curves for a number of operating points of the engineas input to the model, results were produced for different crank angle intervalsshowing deviations between the developed torsion models and a reference models estimation of torsion. Due to the damping approximation used in the model, high initial deviations could be found at certain operating points beforereducing the number of vibrational modes. These initial deviations weregreatest for the first two cylinders. Results from the model reductions showed that using the first three vibrational modes in the torsion model, is sufficient for estimating the torsional displacement between the flywheel and all cylinderswith an accuracy of within 0.1 degrees, with the exception of the first two cylinders for the early and late combustion interval.

The aim of my thesis is to create a procedure for the calculation of con rod stress in MBS Software. The thesis contains several parts, i.e. a short research of contemporary con rods, con rod modelling with the use of Pro/E, methodics of the finite-element con rod model preparation and model analysis in ANSYS Software, creating of virtual combustion engine template with flexible con rod and carrying out a strain hardening analysis in ADAM/Engine software. The theme of my thesis is quite demanding in the combination and the use of several computer software programmes. The thesis offers a survey of possibilities, procedures and methodics of con rod stress solutions that help to clarify the matter.

This master’s thesis deals with the piston for modified engine 1.4 TSI from Volkswagen concern. It includes calculation of kinematics and forces reactions of the crank mechanism of the engine for speed 6071 rpm elaborated in the program Mathcad Prime. Further the work includes calculation for reducing the magnitude of lateral force and design of several variants of the piston. For the proposed design variants of the piston are performed FEM analysis of mechanical state of stress and comparisons of contact pressures in the program ANSYS Workbench.

This article contains description of basic principles of stirling engine, construction types and its parts, which supplies motor run and description of using in real life too. The main topic is analyses of driving mechanism supplying both pistons movement of stirling engine on Robert Stirling‘s drawing from 1816.

The main aim of this master’s thesis is to design the powertrain of turbocharged threecylinder in-line gasoline engine based on given parameters. The work introduces three variants of balancing of inertia moment of rotating masses and balancer unit of first order moment of inertia of reciprocating parts. The thesis also presents calculation of torsion vibration of the powertrain and structural design of the rubber damper. In conclusion a stress analysis of the crankshaft is submitted with and without torsion vibration damper.

The main aim of this master’s thesis is to design the drivetrain of four-cylinder gasoline internal combustion engine with torsional vibration rubber dumper. For the basic parameters of the engine are designed two optional crankshafts. Crankshaft with eight counterweights and crankshaft with four counterweights. The thesis also includes modal analysis of the crankshaft using FEM, and design of the main dimensions of the dumper. The following part describes the calculation of force torsional vibration and safety factor solution of crankshaft fatigue using FEM. The final calculation is of the temperature field in the rubber dumper in selected operating modes.

Les récentes séverisations des normes d’émission a indirectement conduit le groupe RENAULT à durcir et optimiser les spécifications appliquées aux surfaces en contact. Les portées de vilebrequins sont particulièrement concernées. A l’instar des développements produit/process liés au rodage des fûts de cylindre, il est envisagé depuis peu d’appliquer une texturation antifriction sur les tourillons et manetons. Ces portées de paliers sont actuellement superfinies par toilage, un procédé d’abrasion à la fois robuste et économique. Malheureusement, le toilage produit, en usine du moins, une unique morphologie de surface, à savoir, une striation circonférentielle intégrale. Il apparaît, en ce sens, très limité. La présente étude a pour objectif d’investiguer plus finement les capacités de texturation du toilage. Elle propose un ensemble d’analyses expérimentales visant à comprendre les limites texturales observées en production série et offre des solutions innovantes afin d’accroître très sensiblement le potentiel texturant du procédé. S’articulant autour du triptyque Procédé/Texture/Fonctionnalité, ce travail se positionne également dans une démarche globale en s’intéressant à la fois à la texturation laser, la caractérisation des surfaces texturées et à l’influence des textures sur la fonctionnalité statique et dynamique des paliers. Les résultats montrent en particulier que le procédé de toilage est capable de produire, de manière robuste, une véritable diversité de textures. Ils montrent également que la recherche de « poli miroir » pourraient être à prioriser sur les portées de vilebrequins. / The recent introduction of tougher emissions standards has indirectly led the RENAULT group to tighten up and optimize specifications applied to surfaces in contact. Crankshafts journals are particularly concerned. Like product/process developments linked to the honing of cylinder liners, there have been recent plans to apply anti-friction texturing to crankshaft journals and crank pins. These bearing surfaces are currently super-finished by belt-grinding, an abrasion procedure that is both robust and economical. Unfortunately, belt-grinding produces a unique surface morphology, in the factory at least, i.e. integral circumferential striation. In this sense it appears very limited. The purpose of this study is to investigate in more detail the texturing capacities of belt-grinding. It provides a set of experimental analyses aiming to understand the textural limits observed in the factory and offer innovative solutions to significantly improve the texturing potential of the procedure. Focusing on the three-pronged Process/Texture/Functionality approach, this work is also part of a global process by looking both at laser texturing, characterization of the textured surfaces and the influence of textures on the static and dynamic function of the bearings. The results show in particular that the belt-grinding procedure is capable of robustly producing a real diversity of textures. They also show that striving to achieve a « mirror-polish » finish may be something to prioritize for crankshafts journals.

O objetivo deste trabalho foi a análise de estratégias de retificação de virabrequins automotivos forjados utilizando rebolos de CBN vitrificados em altas velocidades. As estratégias analisadas foram: a retificação de mergulho (estratégia A) e a retificação axial (estratégia B). Foi proposta uma nova estratégia de retificação, denominada estratégia C - retificação axial múltipla, sendo esta inédita. Nesta subdividi-se o espelho do virabrequim em trechos, retificando-se o sobremetal radial do espelho em múltiplos estágios. Os aspectos teóricos das estratégias foram determinados, apresentando-se uma formulação matemática para o cálculo da taxa de remoção de material específica ao longo do perfil do rebolo utilizado. Testes comparativos foram realizados em que os principais aspectos para uma retificação eficiente foram determinados. Primeiramente verificou-se a necessidade de uma operação de dressagem efetiva, a fim de se obter uma agressividade na face do rebolo necessária para evitar o empastamento do mesmo e a queima do espelho. Para tanto, além da escolha correta da configuração e dos parâmetros de dressagem verificou-se a necessidade de um sistema de monitoramento que permita a detecção e a avaliação de possíveis não-conformidades. A utilização de um sistema de fluido de corte e de limpeza a alta pressão eficientes contribuíram para a redução dos cavacos alojados na porosidade do rebolo, evitando assim seu empastamento prematuro. Com base no modelo teórico proposto foi possível determinar-se a região de máxima solicitação do rebolo em função das estratégias adotadas, possibilitando o planejamento e a adoção das condições de usinagem mais favoráveis na redução do desgaste do rebolo e, por conseqüência, os desvios geométricos da peça usinada. Nos testes comparativos entre as estratégias verificou-se a possibilidade de utilização de todas. Porém, cada qual apresentando suas particularidades. Considerando-se o mesmo tempo de corte, a retificação de mergulho (estratégia A) apresenta a menor taxa de remoção de material específica e a mais ampla região de máxima solicitação do rebolo, sendo esta fixa e igual ao sobremetal no espelho. Neste caso a área sujeita ao desgaste na ferramenta é maior. De forma oposta, a estratégia B (retificação axial) apresenta a menor região de solicitação da ferramenta, sendo esta igual ao avanço axial por volta. Todavia nesta estratégia a taxa de remoção de material específica é máxima, sendo função do sobremetal radial da peça, diferença entre os raios máximo e mínimo do espelho. Nesta, a área desgastada será mínima, porém, esta região sofrerá a máxima solicitação e maior desgaste, com risco de empastamento do rebolo e queima da peça. A adoção da retificação axial múltipla (estratégia C) permite combinar a flexibilidade da alteração da região de máxima solicitação do rebolo com variações na taxa de remoção de material específica para cada estágio, reduzindo a tendência de queima e empastamento do rebolo, caracterizando-se como uma solução intermediária entre a retificação de mergulho e a axial. Verificou-se que a variação no número de estágios tem influência direta no volume de material removido e no desgaste radial do rebolo. Uma simulação foi desenvolvida para o desgaste radial do rebolo para cada estratégia testada. / The aim of this study was the analysis of grinding strategies for high speed grinding of forged automotive crankshaft using vitrified CBN wheels. The grinding strategies tested were: the plunge grinding (strategy A) and the face grinding (strategy B). A new grinding strategy was proposed, the multi-steps face grinding, which is innovative. In this strategy, the sidewall is divided into circular regions, removing the sidewall stock into multiple steps. The theoretical aspects of each strategy were determinate and the mathematic formulation for the specific material removal rate calculation along the wheel profile is presented. Comparative tests were performed in which the main aspect for an efficient grinding operation were determinate. First of all, the necessity of a high efficient dressing operation was detected, in which the achieving the adequate sharpness of the dressed wheel sidewall is mandatory to avoid the wheel loading and the workpiece sidewall burning. For that, besides the correct configuration and selection of the dressing parameters, it was noticed that a monitoring system is essential for the detection of non-adequate dressing operations. The adoption of an improved cutting fluid application system and scrubbers (high pressure nozzles) leaded to chips clogging reduction and premature wheel loading. Based on the proposed theoretical model it was possible to determine the region of the maximal wheel strength due to the adopted grinding strategy, allowing the process design, including the most favorable cutting conditions for the workpiece geometrical errors avoidance. In the comparative test among the strategies, it was possible to verify that all strategies can be adopted, although each of them with their particularities, which must be taken into account. Considering the same cutting time, the plunge grinding strategy (strategy A) presented the lowest specific material removal rate and the widest affected wheel region, which is fixed and equal to the sidewall stock. In this situation, the worn area is the widest. On the other hand, the face grinding strategy (strategy B) presented the narrowest affected area, with width equal to the axial infeed. Although in this strategy, the specific material removal rate is maximal, depending on the radial stock of the sidewall. The worn region is the narrowest, but the with greatest wheel wear values will be observed in this region. The wheel loading and the workpiece burn can easily occur. The adoption of the multi-steps face grinding (strategy C) allows the combination between the flexibility of changing the width of the affected wheel region and the specific material removal rate for each step, reducing the occurrence of workpiece burn and wheel loading. It is an alternative between the plunge grinding and face grinding. It was possible to verify that the number of steps has a direct influence on the volume of removed material and on the wheel wear. A simulation was developed for the wheel wear for each strategy.

"Due to the dramatic growth in the use of Wireless Sensor Network (WSN) applications - ranging from environment and habitat monitoring to tracking and surveillance, network research in WSN protocols has been very active in the last decade. With battery-powered sensors operating in unattended environments, energy conservation becomes the key technique for improving WSN lifetimes. WSN Medium Access Control (MAC) protocols address energy awareness and reduced duty cycles since the radio is the component that consumes most of the energy. This thesis investigates the performance of two recently published energy-aware MAC protocols, Crankshaft and SCP-MAC. Crankshaft has been shown to be one of the best protocols in terms of energy consumption in dense WSNs while SCP-MAC has a dedicated low duty cycle and low average latencies. The focus of this investigation is to discover techniques for reducing the latency of Crankshaft. Using OMNeT++, an open source and component-based simulation framework, this study investigates possible modifications to Crankshaft to improve its latency. The potential improvements considered include modifications to Crankshaft’s retransmission contention scheme (Sift), adjustments to its inherent settings, and investigating the impact of ACKs. Since OMNeT++ readily provided only a variant of SCP-MAC identified as SCP-MAC*, the simulations results presented involve comparing variants of both protocols (Crankshaft and SCP-MAC*). The performance of these protocols is also analyzed using distinct sensor node communication patterns. It was determined that Crankshaft’s latency depends on its ACK/Retransmission settings. Specifically, Crankshaft has the best latency with No ACKs, without much loss in energy consumption. But the latency can also be improved when ACKs are enabled by reducing the number of retries. Furthermore, the latency and delivery ratio are also directly governed by the WSN traffic pattern and the congestion in the network, as there was a noticeable improvement for both parameters in one-hop traffic, compared to multi-hop convergecast traffic to the sink. Finally, it was observed that Crankshaft’s broadcast performance in flooding traffic can be improved by increasing the number of broadcast slots used, though this is detrimental to its performance in unicast traffic."