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The role of the engine brake is to convert a power-producing engine into a power-absorbing retarding mechanism. Modern heavy-duty vehicles are usually equipped with a compression braking mechanism that augments their braking capability and reduces the wear of the conventional friction brakes. This work presents an engine brake mechanism modeling and design based on decompression effect, obtained by exhaust valve opening during the end of the intake cycle. Besides that, during the system operation the emissions are drastically reduced, even eliminated, since there is no fuelling, contributing to pollution level reductions. In this sense, this work describes a development of such engine brake system for a 4 and a 6 cylinder diesel engines. The engine brake performance was predicted by the development of 1D engine models.

The demand for low level emission engines increase the need for new technology development due to the necessity to fulfill legislation requirements without fuel consumption and engine performance deterioration. Diesel engine power, torque and fuel consumption are greatly influenced, among other variables, by the combustion chamber and piston bowl shape, the engine compression ratio and the shape and size of the intake and exhaust ports and valves. So, the intake port design optimization, taking into account the air mass flow and swirl are of great interest. In this sense, this work describes the procedures and results of the intake port design and optimization through CAD and CFD modeling and also with flow test bench results. It is showed the improvements in a four valve cylinder head, regarding the requirements of an Euro IV Diesel Engine.

This work presents the results and methodology of a dynamic durability analysis considering the interaction between crankcase and crankshaft. The approach is based on a robust mathematical model that couples the dynamic characteristics of the crankshaft and crankcase, representing the actual interaction between both components. Dynamic loadings generated by the crankshaft are transferred to the crankcase through flexible 3D hydrodynamic bearings. This methodology is referred to as hybrid simulation, which consists in the solution of the dynamics of an Elastic Multi-Body System (E-MBS) coupled with the Finite Element Methodology (FEM). For this study, it was considered an in-line 6-cylinder diesel engine used in off-road applications. The crankcase design must withstand higher loads due to new calibration targets stipulated for PROCONVE (MAR-I) emission regulations.