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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.

This work brings and proposes a simulation methodology to virtually investigate a 2-stage Turbocharger application for a heavy duty diesel engine. The motivation of the work is the research and development of an engine which is supposed to comply with very restrictive emission regulation policies, namely Euro V, VI and EPA 10, besides Tier 4 Final. Although emission level is, itself, a main concern (mainly NOx and engine-out PM), the present work present a methodology which covers air flow and boost ability of the entire engine and it is designed to be able to properly evaluate turbocharger designs possibilities (TC matching). In order to find the unknowns of the physical problem and, then, to verify the methodology success, some not usual measurements were done, such as of TC shaft speed using NVH techniques.