Title

Simulation of an Automotive Catalytic Converter Internal Flow

Document Type

Conference Proceeding

Publication Date

9-14-2005

Publication Title

Internal Combustion Engine Division Fall Technical Conference

Conference Name

ASME 2005 Internal Combustion Engine Division Fall Technical Conference

Abstract

Catalytic converters have been used for a number of years in the United States to control automotive pollution. A catalytic converter needs to reach a certain temperature before the chemical reactions take place (light-off). Recently, the new regulations on emission standards have prompted a reconsideration of the design of automotive catalytic converters in order to reduce the light-off period of the catalyst. The catalytic converter light-off period is very Important since almost 80% of the emissions from vehicles occur within the first three minutes after cold start in the FTP-75 test. In order to meet these new regulations, current studies have suggested that the catalyst should be “close-coupled”; that is fitted close to the engine exhaust manifold. In order to design “close-coupled” converters, the designer may have to resort to truncated inlet and outlet cones, or distorted inlet pipes due to space limitations. Hence, it is very difficult to achieve good mixing of the exhaust gas, and a good flow distribution at the inlet cross section of the monolith. Based on such a current status in the study of the catalytic converter, the present work focuses on the time-dependent flow patterns, both in the exhaust manifold and the catalytic converter using Computational Fluid Dynamics (CFD). A three-dimensional grid model of an engine exhaust manifold and a close-coupled catalytic converter was developed and analyzed. The flow simulations were performed using KIVA-3 for non-reacting flow fields. These simulations were performed with transient boundary conditions applied at the inlet to the exhaust runners to simulate the opening and closing of exhaust valves. The CFD results were used to study flow uniformity under different operating conditions and to identify the best location for the oxygen sensor.

Comments

https://doi.org/10.1115/ICEF2005-1339

Rights Statement

© 2005 by ASME

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