Influência da degradação de catalisadores de três vias nas emissões de NH3 e N2O em motociclos.

Abstract

PROMOT was implemented in 2002 due to the growth of the motorcycle fleet and the relevance of its pollutant gas emissions. The program stipulated a schedule for the gradual reduction of emissions, requiring the adoption of new technologies and aftertreatment systems to meet the imposed limits. In 2009, the implementation of electronic fuel injection systems and catalysts on motorcycles began. During the process of converting pollutants into catalysts, and due to less control of the air/fuel ratio in the engines of these vehicles, the formation of unwanted unregulated compounds, such as ammonia (NH3) and nitrous oxide (N2O), may occur. NH3 in the atmosphere participates in the formation of secondary pollutants, especially the ultra-fine particulate matter. N2O remains for long periods in the atmosphere with a high potential for the greenhouse effect, about 300 times higher than that of CO2. The present study presents the effects of the degradation of the three-way catalyst on the emissions of these compounds, as well as of the pollutants legislated, in an M3 phase motorcycle. For the development of the research, experiments were carried out on a chassis dynamometer, using catalysts with different mileage accumulations. The results showed that legislated and non-legislated emissions are affected in different ways with the increase in mileage, but this parameter has little impact on cold emissions, which is explained by the low catalyst action in these conditions. INTRODUÇÃONas últimas décadas houve um aumento no uso do transporte individual, tornando a frota de veículos leves de passageiros e motociclos um problema nos grandes centros urbanos. O aumento da frota, associado à queima de combustíveis, contribui para a degradação da qualidade do ar, provocando sérios danos à saúde e ao meio ambiente. No Brasil, como em outros países, essa preocupação não é recente. Na década de 1980, planejou-se e implantou-se o