The paper describes a new test strategy used during the development and design verification phase of catalytic converter systems. For close-coupled catalyst applications the following increased loads are evaluated: 1. The gas inlet temperature into the converter increases by 60 to 100 deg C per meter pipe length closer to the engine. 2. Temperature transients dT/dt can increase from approx. 1000 deg C/min at U/F position to approx. 2500 deg C/min, depending on the configuration of the application. 3. HC pre-reactions decrease due to the lower dwell time before entering the catalytic converter and therefore cause higher bed temperatures due to a more severe exothermal reaction. 4. Vibration levels can increase up to 1200 m/s2 and even more, depending on the application and the engine type. 5. Response frequency spectra of the vibration is shifted to higher frequencies. 6. Failure modes occuring during engine or vehicle testing give information about necessary design modifications of the converter which must be verified in a revised component test (iterative process). 7. An Engine Thermal Cycling Test was completed over 1000 cycles on a metal supported catalyst in a close-coupled position at 965 deg C maximum gas inlet temperature and an over all vibration level of 960 m/s2 without any degradation.
Development of more exacting test conditions for close-coupled converter applications
1997
20 Seiten, 10 Bilder, 5 Tabellen, 18 Quellen
Conference paper
English
Development of more Exacting Test Conditions for Close-coupled Converter Applications
British Library Conference Proceedings | 1997
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Development of increased test conditions for close-coupled catalyst applications
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