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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.

Lately the simulation of driving cycles through the vehicle's longitudinal dynamics has become increasingly important and common for engineering design. Consequently is essential to evaluate the performance of the simulation through consistent validation metrics that allows a qualitative and quantitative analysis of the data. This paper presents a simple systematic mechanical model that estimates the fuel consumption of an arbitrary small-size hatch back in a specific driving cycle, with all the modeling details of the energy balance throughout the system, as well as, the procedure of the test that reproduces the simulated conditions and the validation methods with different validation metrics. Besides, this work examines how the present metrics should be interpreted for assessing computational model accuracy, as well as, the impact of experimental measurement uncertainty on the accuracy assessment.

For intricate automotive systems that enclose several components, such as gearboxes, an important aspect of the design is defining the correct assembly parameters. A proper assembly can ensure optimized operating conditions and therefore the components can achieve a longer life. In the case of the support bearings applied to front-axle lightweight differentials, the assembly preload is a major aspect for an adequate performance of the system. During the design phase it is imperative to define reference values to this preload, so the application would endure its requirements. However, with the assistance of computer simulations, it is possible to determine an optimum condition of operation, i.e. optimum pre-load, which would increase the system reliability.

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.

One of the vital parts in the modern motor vehicle is the transmission. Any fault on the system can hazard the usage of the vehicle, especially if the fault occurs during the operation, in that case safety will be an issue. Thus, in order to improve reliability and durability of transmissions systems and its components, virtual simulations can help the designer to overcome faulty conditions during the design conception. However, many times the simulations do not relate to the real world application, due to simplification and assumptions that were formally known as appropriate. For that reason, during the process of designing a transmission bearing, it would be important to take into account the housing stiffness effects on the bearings. In this work, three different cases will be evaluated. In first case, bearings life will be simulated on an analytical software with a rigid housing.

In the track to fuel efficiency increase and green house gases emissions reduction, systemic friction reduction in mechanical components starts to play a big role in the complete automotive system design. When thinking on design for friction efficiency, most of the common applied mechanical components still have enough room for improvement, so as to greatly impact the whole mechanical efficiency. Following the results obtained by a Design and Analysis of Computer Experiments - DACE investigation on the most influencing friction torque parameter of roller bearings, different designs of raceway profiles were examined in order to reduce the bearing friction, i.e., increase its efficiency. In this work a DACE methodology was applied alongside a friction model for the roller bearings to evaluate the effects of the variables and its interactions.

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.

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.

The development area of the bearing's industry constantly searches for a better efficiency and a lower film oil thickness in surfaces with high roughness under relative motion. In these cases, operational conditions like high loads and temperatures, as well as low safety margins for weight and size, considering the lubricant viscosity, should be taken into account as fundamental design parameters. In order to know better the elastohydrodinamic lubrication effect, firstly, it is necessary to understand deeply and accurately the applied loads on the ball element bearings. For this purpose, the accurate analysis and study of the performance of these machine components is carried out, using analytical methods and giving special focus on the velocities and accelerations involved, as well as different types of loads applied on the ball element and their distribution and consequences during the ball motion inside the bearing rings.