Search Results

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.

Internal combustion engine noise and vibration are major issues for car makers, and these are even more important for High-Level Pick-ups and SUV's which applies modern diesel engines. One important player in this scenario is the second-order unbalanced forces vibration produced by the conventional in-line 4-cylinder engine configurations, which leads to high-frequency excitation of vehicle's structure and consequent internal noise. This paper studies a balancer shaft solution for the mentioned engine configuration, as well as major design alternatives and development process and issues. This paper also presents an example of a balancer shaft design and development for a high speed diesel engine, as well as proposes a design/decision matrix methodology. Such methodology, which can be applied to any design or engineering case, helps design engineers make the right decision amongst different options by using a very simple and objective matrix.

Withdrawal of heat from internal combustion engines is a major concern in today's automotive industry, mainly due to material constraints and components durability. A well-designed cooling system may increase engine's reliability. In the light of this, a numerical study has been conducted to analyze the water flow inside MWM INTERNATIONAL's high-speed diesel engine. The study has been done in order to determine possible cavitation and boiling regions, which can reduce the heat transfer efficiency. The analysis was carried out with the help of computational fluid dynamics (CFD) commercial software ANSYS FLUENT®. The flow was considered to be steady-state, turbulent, with heat transfer and the fluid was treated as a single phase. For this reason, the possible cavitation and boiling regions are identified through vapor pressure and boiling temperature, respectively.

Diesel combustion is a complex, turbulent, tree-dimensional, multiphase process that occurs in a high-temperature and high-pressure environment. For the Diesel combustion studies the knowledge of the temperatures in the different areas of the fuel spray after the ignition process is fundamental. Starting from the knowledge of such temperatures, it is possible to study the mechanism of the main pollutants formation such as the particulate matter and NOX. The present work proposes an extension of the phenomenological model of particulate matter emission, previously proposed by the author, now with the objective of foreseeing the temperature in some fundamental regions of the Diesel spray in combustion, like the region adjacent to the diffusion flame, where the oxidation of great part of the particulate matter occurs and where the production of the thermal NOX, which is responsible for the main part of the NOX emissions, takes place.

Withdrawal of heat from internal combustion engines is a major concern in today's automotive industry, mainly due to material constraints and components durability. In this sense, a numerical study was conducted to analyze the water flow inside MWM INTERNATIONAL's high-speed diesel engine, in order to determine possible cavitation regions, which can reduce the heat transfer efficiency. The analysis is carried out with the help of computational fluid dynamics (CFD) commercial software FLUENT, from ANSYS Inc. The model was built as steady-state, turbulent, single phase flow. Heat transfer from the solid water jacket to the fluid zone was also considered. For this reason, the cavitation regions were identified through vapor pressure.