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The constant growth of the automotive market demands for comfort to the user and energy efficiency have caused the intensification of the industry researches and development of the automatic transmissions (AT). However, vehicles equipped with these gearboxes entails in higher fuel consumption levels than the one required by vehicles equipped with manual transmission. In the automotive industry due to the advantages offered using computer simulations, such as fast evaluation an optimization, many researchers are using virtual models for optimization of dynamic behavior of systems and fuel consumption. Aiming to study the dynamic behavior of an AT and the influence of its components on that behavior, this paper presents an AT dynamic model developed in MATLAB® / Simulink®.

This paper presents a standardization model for the analysis of rolling bearings in transmission systems. A procedure was applied to assist gearbox prototype development. A solid methodology with robust software, based on international standards, allowed the development engineers to shorten simulation time. In this case, the calculations were performed taking into account system elasticity, which resulted in an exact calculation of the internal load distribution in the bearing, including contact pressure, tilted position and with rolling element profile, considering effects of lubrication conditions and contamination. The program also evaluates the resulting forces of gears, displacement, shaft deflection, contact pressure, stresses, torsion and inclination of the shafts. All the information processed aims at providing safe design, optimal solution and cost impact.

To overcome the proposals concerning to the reduction of the fuel consumption and gases emissions required by the regulatory councils around the world, but also required by the actual market, since economic vehicles have been more valorized than ever, the automotive industry have dispended considerable efforts in the development of new technologies, such as hybrid cars, and in the improvement of the current projects. Friction of any magnitude retards the motion and results in energy loss, causes temperature increase and should be reduced in order to improve the system efficiency. This paper intends, by means of analytical calculation based on dynamic systems and comparisons with Finite Elements Analysis, propose a robust method to analyze friction losses in automotive mechanical systems. Transmission application was chosen to conduct this analysis.

One of the great challenges of engineering teams nowadays is to overcome long and costly project experimentation phases. One effective way of decreasing such project demands is to come up with a firsthand prototype with high success probability. In order to do so, the project team should rely on robust numerical models, which can represent most of the real-life product behaviors, for instance system dynamics. For rolling element bearings, such dynamic models have to consider the dynamic interactions between its components, i.e., rolling elements and raceways. The only vibration transmitting points on rolling element bearings are the lubricated contacts. Therefore, in order to represent the full bearing dynamic behavior on a numerical model, an efficient transient contact model, which depicts the actual contact behavior, is fundamental.

Sustainability is the focus of most engineering projects nowadays. The challenge of taking the efficiency to its maximum, in order to reduce the CO₂ emission, became so hard that even a minor innovation is a relevant step. Among the efficiency villains in automotive branch it is possible to quote the mechanical friction losses. One of the main factors concerning to these sort of losses is the contact pressure in rolling bearings. This pressure is highly influenced by singularities on raceways. Different geometry profiles can be a friction source, affecting the usage and leading to a wasteful exploitation. This paper aims to scrutinize the influence that different abnormalities on raceways has on the contact pressure of high speed and low load axial ball bearings. The study will be based on numerical simulations on a contact calculation software. The contact pressure will be evaluated around the edges of dented, bulged, grooved and ridged profiles.

Each year more strict laws and regulations concern the environmental impact of green house gases of general vehicles. Hence, any step taken towards a systemic efficiency increase of internal combustion engines and power-trains revels great a deal of emission reduction downstream the fuel consumption chain. Most of such mechanical systems depend on friction reduction elements, such as special low-friction coats and rolling element bearings, even so there is still some power loss on these components. In order to reduce such losses due to friction, in other words increasing the component's efficiency, this work applies the Design of Experiments -DoE methodology along with the frictional torque simulation in an automotive application to asses the effects of the variables and its interactions involved in the friction torque theory. For simulation studies a Response Surface Design is generated and Box-Behnken Design is carried out.

More efficient and more reliable methods to analyze the performance of the bearing test samples help to reduce validation time during development of rolling bearings. This paper presents a study of the impact on airborne noise and structural borne noise of especial prepared rolling bearings with angular contact submitted for durability tests. The study aims to link specific bearing failures to characteristics in airborne noise and structural borne noise using for instance the “envelope technique”. In the future these patterns will enable more effective online monitoring of failure evolution.

At this time, each major automotive market bares its own standards and test procedures to regulate the vehicle green house gases emissions and, thus, fuel consumption. Hence, much are the ways to evaluate the overall efficiency of motor vehicles. The majority of such standards rely on dynamometer cycle tests that appraise only the vehicle as a whole, but fail to assess emissions for each component or sub-system. Once the amount of work generated by the power source of an ICE vehicle to overcome the driving resistance forces is proportional to the energy contained in the required amount of fuel, the power path of the vehicle can be straightforwardly modeled as a set of mechanical systems, and each sub-system evaluated for its share on the total fuel consumption and green house gases emission. This procedure enables the estimation of efficiency gains on the system due to improvement of particular elements on the vehicle's driveline.

There are large numbers of variables that affect seal performance, for example, temperature, grease and dusty. This paper aims the study one of these variables, the swelling. Swelling is the absorption of the liquid by the rubber and this liquid absorption can deeply alter physical and chemical properties and hence change tensile strength, extensibility and hardness of the rubber. A review about seal and the characteristics of the seal performance will be made and also a study about what this phenomenon affects the seal performance. Thus the purpose of the present paper is to develop the conception of swelling by investigating the characteristics of swelling deformation.

Heating generation in rolling bearings is a critical point for development and application, specially for heavy trucks. Several problems can occur in the rolling bearing and in the system when the temperature increases. For example, at high temperature levels the rubber sealing can change its proprieties and volume, creating a high interference at the contact with the rings. The grease can also be affected and modify its viscosity, generating a possible leakage, which is not allowed during life. This papers aims to study the heat generation and evaluate, experimentally, the temperature stabilization in clutch release bearings for heavy duty application. With this purpose, several tests were performed and the results were analyzed to find the main factors that can be influenced.

As a common trend on the automotive development process, the increase in system efficiency became a major concern for design engineers nowadays. Several are the focuses at which such topic can be dealt with, including full systems upgrades, electrification and component level optimization. However, there are simpler ways to increase efficiency by only replacing construction concepts that have always been taken for granted. This is the case of replacing the sliding friction of the camshaft hydrodynamic bearings by rolling elements. The direct reduction of the power consumption, when applying rolling element bearings to the camshaft, is a straightforward method to increase the liquid torque available at the crankshaft, hence enabling downsizing. In this paper some design solutions and the structural integrity of the system will be assessed and, most of all, the reduction on the friction torque, hence the increase in system efficiency, which leads to CO₂ emission reductions.

The main purpose of the lubrication in the rolling bearing is to avoid and to reduce the metal to metal contact, thus it is possible to reduce the friction and to prevent the wear between the balls and the raceways. Consequently, the rolling bearing should work with grease or oil inside to guarantee an oil film between the balls and the raceways, thus this grease should stay inside the bearing. To avoid the grease loss the bearing normally may have a sealing but even so a little grease loss can occur. Hence the present investigation was initiated because of the need to understand a grease loss and the basic parameter that has influence on this. To help the elaboration of the experimental tests was used a DOE technique, thus it was possible to determinate simultaneously the individual and interactive effects of many factors that affect in the grease loss.

One of the steps towards higher efficiency internal combustion engines (ICEs) is the application of new improved subsystems, with lower power consumption. One of such subsystems is the needle roller bearing valvetrain, where rolling bearings replace the common sliding bearings designs as camshaft supports, hence decreasing the frictional torque and increasing liquid power at the crankshaft. However, the first question to arise is the vibration characteristic of the system for the new design. In order to initiate the assessment of the vibration behavior of the camshaft, some fundamental investigations should be made, such as natural frequency identification. For that, one might benefit from virtually evaluate these characteristics via FEA / Rotordynamics algorithm, reducing the need for expensive experimental setups of the complete valvetrain. This work intends to assess the applicability of these both methods to the camshaft vibration problem.

In recent years vehicle ergonomists have begun dedicating effort towards the study of human motion in the vehicle regarding moving comfort when using commands such as the steering wheel, gear shift and pedals. Correlation between subjective responses of human comfort and the maximum force achieved during the end-of-travel impact and the average slope of the force-displacement curve during the initial disengagement phase is difficult [1]. When end customers complain about clutch pedal actuation comfort, car salesmen and automakers change the entire clutch system, including pressure plate, clutch disc and clutch release bearing (CRB) to solve the problem and the suspicious root cause lies on the CRB. In most cases, previous analyses showed bearing still functional but strong contamination inside the bell housing, on the clutch and between the CRB with plastic housing and the sliding tube.