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The improvement of fatigue life in parts subjected to cyclic stresses by application of mechanical surface treatment processes is already well known, both in the industry and in the academy. Speaking of automotive springs, the shot peening process becomes an essential step in manufacturing these parts. In the case of leaf springs, however, a systematic investigation of the effect of shot peening on fatigue life is still required. The aim of this work is to improve the knowledge of shot peening on leaf springs for vehicles through fatigue tests on a series of samples that were subject to different peening processes. A second shot-peening after a first peening under stress (stress peening) led to a higher durability comparing to the conventional process, opening an opportunity of vehicle weight reduction.

The preset process is largely applied on coil spring manufacturing. It is mainly used to guarantee, under work load, that the spring doesn't plastically deform changing the original dimensional restrictions. However, the difficult to predict its behavior under permanent strain is a constraint on projects. All the spring calculations are based on its final geometry (after the preset process), and today the initial geometry definitions are based on empirical information. The aim of this paper, through F.E.M. and experimental work, is to comprehend the stress-strain phenomena involved on the preset process, in order to create a new methodology to design coiling tools.

The application of finite element method (FEM) is widespread used to structural analysis. However the prescription or the consideration of a porous material parameter is still challenging. Thus, this work proposes a methodology applied to the finite element method considering a value of porosity. The goal is evaluate the structural behavior considering prescription of material porosity for 03 (three) loading conditions: analysis of natural frequencies extraction; analysis for concentrated load; analysis for inertial loading. Also is presented a comparison between different mesh refinement (size of element), and damaged elasticity modulus.

The development of computational procedures has allowed increasing the range of virtual analysis of various engineering problems. The design of industrial products must meet requirements of durability, strength, reliability, security, and criteria of low cost and weight. These requirements are among the many reasons that enable technological advances; and such advances are needed to make possible to increasingly use software's capacity of simulating real operating conditions of components. This work has as main objective to achieve fatigue analysis of a connecting rod of an automotive internal combustion engine by using software based on finite element method. For this were used curves of loads and boundary conditions, obtained from experimental analysis of the component, so it may be possible a correlation between experimental and computational results.

The increasing number of flex fuel vehicles using pure or mainly ethanol when mixed with gasoline led to a necessity of an auxiliary cold start system. These systems are based on introducing gasoline during the engine's cold phase. The researches lead to find an alternative to avoid using gasoline at cold start systems. This works presents a numerical analysis of the flow and heat transfer in a cold start system, using computational fluid dynamics. A prototypal vehicle was used to validate the simulations. The tests were done at controlled ambient temperatures: 0°C for cold start measurements and 25°C at chassis dynamometer to run the FTP75 emission cycle. The numerical data were validated and the results showed the possibility to get a temperature high enough to assure fuel combustion with emissions benefits.

The use of pure ethanol or the prevailing of it in the mixture with gasoline in flex fuel engines, led to a necessity of an auxiliary system to the cold start and engine functioning. Ethanol chemical properties can be used to explain this necessity. Ethanol is been used in Brazil for more than 30 years and many researches give support to the cold start technologic evolution. The cold start system enables the gasoline introduction into the intake manifold of flex fuel engines, when vehicles are using pure ethanol or a mixture with more ethanol than gasoline. The researches challenge is to find a way to start an engine using ethanol without the use of the cold start system using gasoline. This works presents a numerical analysis of the flow and heat transfer in a cold start system, using computational fluid dynamics. An experimental test bench developed to study a start cold system heating air and ethanol.

The need of mass reduction of automotive engines, aiming at greater performance of the vehicle and cost reductions, demands the research for optimized forms of all its components. The mass minimization of all parts of the engine is not limited only to the optimization of the mechanical project of the part in itself. A part with less weight or volume, saves used material, makes it possible to increase the part production, it facilitates transportation, and, therefore, allows reducing the final cost of the part throughout all its productive chain. In this work the method of Topological Optimization (TO) was applied to project a new geometry, using cast iron, for the alternator and air conditioner compressor bracket of an automotive engine, originally in aluminum. Two geometries had been proposed: one where it is considered manufacture process and another one where it is not considered. The last one was used as step for the optimization of final geometry.