New technology in the automotive industry is the key to success. Therefore, it is appreciated when people come with new design ways to solve problems. This leads to innovation in the automotive industry that will lead to better and more environmentally friendly cars. This report presents a concept on a pushing counter lever spring which provides the same characteristics of force curve as a diaphragm spring in a pressure plate of a car has. The mechanism is to be used for long-term testing and evaluating clutch pedals. The work describes the development process and the manufacture of a prototype. The program Creo (CAD / 3D) is largely used to construct the components. As are the subprograms Mechanism Design and Simulate to simulate the movement and loads. Excel is a great help at the theoretical calculation of the mechanism and to evaluate the theory behind the concept. The result shows how to simulate a diaphragm spring in the pressure plate in a car for long-term testing of clutch pedals. The goal is to accurately mimic the force curve of a diaphragm spring, in order to design better pedals, and thus reduce the weight on the pedals to in turn reduce fuel consumption to protect the environment is one of the most important factors of all in the automotive industry.

<p>Combustion supervision by evaluating flywheel speed variations is a common approach in the automotive industry. This often involves preliminary measurements. An adequate model for simulating flywheel speed can assist to avoid some of these preliminary measurements. </p><p>A physical nonlinear model for simulating flywheel speed based on cylinder pressure information is investigated in this work. Measurements were conducted at Scania in a test bed and on a chassis dynamometer. The model was implemented in MATLAB/Simulink and simulations are compared to measured data. The first model can not explain all dynamics for the measurements in the test bed so extended models are examined. A model using a dynamically equivalent model of the crank-slider mechanism shows no difference from the simple model, whereas a model including a driveline can explain more from the test-bed measurements. When simulating the setups used at the chassis dynamometer, the simplest model works best. Yet, it is not very accurate and it is proposed that optimization of parameter values might improve the model further. A sensitivity analysis shows that the model is fairly robust to parameter changes.</p><p>A continuation of this work might include optimization to estimate parameter values in the model. Investigating methods for combustion supervision may also be a future issue.</p>

<p>The importance of control systems and diagnostics in vehicles are increasing and has resulted in several new methods to calculate better control signals. The performance can be increased by calculating these signals close to optimum, but that also require more and precise information regarding the system.</p><p>One of the wanted control signals are the crankshaft torque and the thesis presents two different methods to estimate this torque using engine speed variations. These methods are Modeling of the Crankshaft and Frequency Analysis. The methods are evaluated and implemented on for a four cylinder SAAB engine. Measurements are made in an engine test cell as well as a vehicle.</p><p>The results show that the Modeling of the Crankshaft method does not produce a satisfying estimation, with a difference of about 200% between estimated and calculated torque. On the other hand, the Frequency Analysis provides an accurate estimation of both mean and instantaneous indicated torque, with a maximum difference of ±20% between estimated and calculated torque.</p>

In this study, effect of fillet rolling process on fatigue performance of a diesel engine crankshaft was investigated. Crankshafts from two different materials, were studied / ductile cast iron EN-GJS 800-2 and micro-alloyed steel 38MnVS6. Resonance bending fatigue tests were conducted with crankshaft samples. Test plan according to staircase test methodology was used. Statistical analyses were carried out with the test data by Maximum Likelihood Estimation method in order to calculate the fatigue limits and construct the S-N curves based on Random Fatigue Limit (RFL) and Modified Basquin models. Fatigue limit calculations were also conducted by Dixon-Mood method and by Maximum Likelihood Estimation methodology for Normal and Weibull distributions. Fillet rolling process was simulated by computer based analysis in order to calculate the compressive residual stress profile at the fillet region to shed more light on the mechanisms and effect of fillet rolling. Fatigue performances of crankshafts from two types of materials were evaluated both at unrolled and fillet rolled states. Effect of fillet rolling load on fatigue performance was also evaluated with steel crankshafts. It was found that ductile cast iron showed better performance under bending fatigue tests than the steel crankshaft both at the fillet rolled and unrolled conditions. On the other hand, fillet rolling process was found to be more effective on steel crankshaft than ductile cast iron crankshaft in terms of fatigue performance improvement. It was also seen that fatigue limit increases with the fillet rolling load up to a limit where surface quality is deteriorated. Residual stress analysis showed that a higher magnitude of residual stress can develop on steel crankshaft fillet region whereas the effective depth of the residual stress is higher on ductile cast iron crankshaft with the same rolling condition. Residual stress analysis of steel crankshafts rolled at different rolling conditions show that, peak residual stress increase with the increasing rolling load is not significantly high and main effect of increased rolling load is the increased effective depth of residual stresses. The MLE methodology used in statistical analysis of the test data was found to be effective for life regression and fatigue strength distributions analysis. RFL model has provided better life regression analysis and fatigue limit calculations than Modified Basquin model. Dixon-Mood method was found to be overestimating the fatigue limit.

This work develops a methodology for the FEM simulation of a multi-piece crankshaft. Various simulation models that include press-fit joint contact conditions and complex meshing schemes are examined in order to accurately capture details of the stress fields present at the stress concentration area (labeled as the SCA) on the edge of the press-fit. The maximum stress components are demonstrated to be of limited values (non-singular) and Hertzian in nature. To obtain the stress convergence sufficiently small elements, which can be determined using a 2-D axisymmetric model, are required at the vicinity of the SCA. The same level of mesh refinement is then used for large 3-D FEM models of the crankshaft geometry, to study the resulting behavior of the press-fit joint for the dynamic operating loads. However, it may not always be possible or practical, as some limits on the mesh refinement have to be imposed to obtain a reasonable computational time to run such models. Less complex 'equivalent' symmetrical FEM models are investigated to determine if these models can provide a sufficient level of accuracy at an acceptable computational effort. Such models may be useful as practical design tools, producing data to speed up the decision making process. The simulation results are compared to some test data for the stress state monitored in real crankshafts under operating conditions. 'Intuitive' design sensitivities to various crankshaft parameters are examined as well. The numerical tools and engineering rules developed in the thesis may be applied to systematically improve the design by extending the joint's life and/or load carrying capability.

Combustion supervision by evaluating flywheel speed variations is a common approach in the automotive industry. This often involves preliminary measurements. An adequate model for simulating flywheel speed can assist to avoid some of these preliminary measurements. A physical nonlinear model for simulating flywheel speed based on cylinder pressure information is investigated in this work. Measurements were conducted at Scania in a test bed and on a chassis dynamometer. The model was implemented in MATLAB/Simulink and simulations are compared to measured data. The first model can not explain all dynamics for the measurements in the test bed so extended models are examined. A model using a dynamically equivalent model of the crank-slider mechanism shows no difference from the simple model, whereas a model including a driveline can explain more from the test-bed measurements. When simulating the setups used at the chassis dynamometer, the simplest model works best. Yet, it is not very accurate and it is proposed that optimization of parameter values might improve the model further. A sensitivity analysis shows that the model is fairly robust to parameter changes. A continuation of this work might include optimization to estimate parameter values in the model. Investigating methods for combustion supervision may also be a future issue.

This work develops a methodology for the FEM simulation of a multi-piece crankshaft. Various simulation models that include press-fit joint contact conditions and complex meshing schemes are examined in order to accurately capture details of the stress fields present at the stress concentration area (labeled as the SCA) on the edge of the press-fit. The maximum stress components are demonstrated to be of limited values (non-singular) and Hertzian in nature. To obtain the stress convergence sufficiently small elements, which can be determined using a 2-D axisymmetric model, are required at the vicinity of the SCA. The same level of mesh refinement is then used for large 3-D FEM models of the crankshaft geometry, to study the resulting behavior of the press-fit joint for the dynamic operating loads. However, it may not always be possible or practical, as some limits on the mesh refinement have to be imposed to obtain a reasonable computational time to run such models. Less complex 'equivalent' symmetrical FEM models are investigated to determine if these models can provide a sufficient level of accuracy at an acceptable computational effort. Such models may be useful as practical design tools, producing data to speed up the decision making process. The simulation results are compared to some test data for the stress state monitored in real crankshafts under operating conditions. 'Intuitive' design sensitivities to various crankshaft parameters are examined as well. The numerical tools and engineering rules developed in the thesis may be applied to systematically improve the design by extending the joint's life and/or load carrying capability.

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.

The importance of control systems and diagnostics in vehicles are increasing and has resulted in several new methods to calculate better control signals. The performance can be increased by calculating these signals close to optimum, but that also require more and precise information regarding the system. One of the wanted control signals are the crankshaft torque and the thesis presents two different methods to estimate this torque using engine speed variations. These methods are Modeling of the Crankshaft and Frequency Analysis. The methods are evaluated and implemented on for a four cylinder SAAB engine. Measurements are made in an engine test cell as well as a vehicle. The results show that the Modeling of the Crankshaft method does not produce a satisfying estimation, with a difference of about 200% between estimated and calculated torque. On the other hand, the Frequency Analysis provides an accurate estimation of both mean and instantaneous indicated torque, with a maximum difference of ±20% between estimated and calculated torque.

This master’s thesis is aimed on design of polymer coating machine that sprays polymer sliding coatings onto surfaces of crankshaft journal bearings used in car engines. At the beginning of this master’s thesis, basic overview of crankshaft bearings design and materials that are used for sliding coatings is given. Then suitable manufacturing technologies for different materials of coatings are described. After describing basic principles of coating technologies and how crankshaft bearings work, main components used for design of the spraying machine are introduced. Three prototypes of the machine are created in virtual environment to verify ergonomics of control and to fulfill safety requirements. In main part of the thesis, description of all parts and subassemblies, such as frame, spraying circuit, pneumatic regulators and safety features is given. Also functions of all parts of the machine are explained in details. Moreover system for handling and manipulation with coated bearings during all necessary technological operations was created. In addition functionality of the machine was verified and checked by spraying of polymer coating on testing samples and crankshaft bearings.