Efeito do uso de recirculação de gases de exaustão (EGR) na contaminação do lubrificante e no desgaste de anel e camisa de motor de combustão interna com ciclo diesel

• Ano de defesa: 2016
• Autor(a) principal: Muraro, Marco Antonio
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Tecnológica Federal do Paraná; Curitiba; Brasil; Programa de Pós-Graduação em Engenharia Mecânica e de Materiais; UTFPR
• Palavras-chave em Português: Motor diesel; Desgaste mecânico; Gases; Engenharia mecânica; Diesel motor; Mechanical wear; Mechanical engineering; CNPQ::ENGENHARIAS::ENGENHARIA MECANICA::PROJETOS DE MAQUINAS::MAQUINAS, MOTORES E EQUIPAMENTOS
• Link de acesso: http://repositorio.utfpr.edu.br/jspui/handle/1/2020

With the increasing trend of stricter regulations related to engine vehicle emissions, the usage of after-treatment systems for the exhaust gases has been intensified. One of the systems used in order to reduce the NOx emission levels is the exhaust gas recirculation system (EGR). However, the EGR usage causes a high formation of particulate matter (soot), which is partly directed to the combustion camera, leading to lubricant contamination and intensifying the wear mechanisms. Several studies have been developed to understand these effects and, although there is a consensus on the most recent results, there are still several contradictory and inconclusive results. To evaluate the influence of soot contamination, a test bench was developed and a diesel engine with EGR rates of 0%, 20%, 35% and 45% was tested. Evaluation of EGR influence on the engine characteristics, oil analysis, weight loss, dimensional changes of the piston rings and the cylinder liner and the roughness of the contact surfaces were evaluated. To observe the wear mechanisms and the formation of anti-wear films, SEM / EDS was used. From the results obtained, it could be seen that increasing the exhaust gas recirculation rate the formation of soot also increases. Additionally, it was found that the temperature increase of the recirculation gases significantly increased the concentration of soot in the lubricant. It was also found several indications of abrasive wear on the contact surfaces and, sliding wear was also observed for the test condition with the highest concentration of soot in the lubricant. Oil analysis, indicated a certain soot influence in the consumption of anti- wear additives along the tests. In addition, EDS analysis showed a small concentration of elements related to anti-wear films along the contact surface, thus supporting the hypothesis of soot particles influencing the formation of anti-wear films. As a recommendation for future work, it is suggested to evaluate the competitive effect between soot particles and additives in the formation of films on the surface.