The performance of a low density, ferritic stainless steel foam as a support structure for automotive emission control catalyst was evaluated, using ceramic and ferritic stainless steel foil monoliths for comparison.
Results for the pressure drop, light-off time, light-off temperature, air/fuel ratio sweep, and vibration tests (at the room temperature and 1000°C) are presented. These tests were conducted at the Southwest Research Institute (SwRI), San Antonio, TX. Test configurations and procedures that are standardized for testing the ceramic and metal foil monoliths were used.
Test results indicated that metallic foams are a viable support structure for automotive catalysts. With the foam-supported catalyst (0.36 L), the conversion of HC, CO and NOx was 90% as efficient as that achieved with catalysts supported on a ceramic monolith (0.62 L) or a metal foil monolith (0.73 L). A need for the optimization of the foam structure and the catalyst formulation was identified.