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The use of numerical simulations in the development processes of engineering products has been more frequent, since it enables prediction of premature failures and study of new promising concepts. In industry, numerical simulation has the function of reducing the necessary number of validation tests prior to spending resources on alternatives with lower likelihood of success. The internal combustion Diesel engine plays an important role in Brazil, since they are used extensively in automotive applications and commercial cargo transportation, mainly due to their relevant advantage in fuel consumption and reliability. In this case, the most critical pollutants are oxides of nitrogen (NOx) and particulate matter (PM) or soot. The reduction of their levels without affecting the engine performance is not a simple task. This paper presents a methodology for guiding the combustion analysis by the prediction of NOx emissions and soot using numerical simulation.

According to [1], nowadays the industry has been receiving an increasingly demand for efficient thermal machines. Particularly in the automotive field, the market is requiring strong reductions in emissions together with fuel consumption. It is important to be aware that the reduction both in emission and fuel consumption represents a challenging task, since it is one of the most complex trade-off of a diesel engine from the engineering standpoint. The present paper describes a comprehensive methodology to reduce the fuel consumption without jeopardizing engine emissions, particularly NOx, and analyze the after treatment durability aspects including urea crystallization hazard and catalyst efficiency. The engineering procedure proposed here comprises the analysis of customer representative route, analysis of customer steady-state chassis dynamometer test and the required emission cycles (European steady-state and transient cycles, ESC and ETC).

A great part of the projects in the powertrain area is focused on the development of more efficient thermal applications. In the end, efficiency is pursued, since the aim is to achieve a sustainable design with low fuel consumption. Thus, vehicles which present lower fuel consumption are demanded by customers. Additionally the emission standards have been reducing the limits of CO₂ emissions to very low levels, which drive engineers to develop vehicles with lower fuel consumption. In summary, the product should now please a more demanding worldwide customer profile as the global economy grows. Vehicle design processes should consider fuel consumption sensitivity taking into account the combined engine and drive train systems at early stages. Frequently the actual fuel consumption can only be confirmed when the first prototype is assembled in order to validate the adopted solutions.

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.