On the basis of fast aging methods development for China’s on-road catalytic converters, SwARC formulated the preparation methods for OBD calibrated catalytic converters and prepared some critical limit catalytic samples for OBD calibration for automobile manufacturers successfully. SwARC chose the fast aging method for critical limit catalytic sample preparation for OBD calibration, which tries to reflect the real on-road HC and OSC deterioration and provide scientific basis for related calibrations.
In practice, certain problems were met such as different HC and OSC tendency deteriorations, obvious difference on HC and OSC deterioration speed for certain catalytic products which leads to these two indexes not in expected ideal index range.
Supported by the experts from Tianjin University, we chose two kinds of catalyst to carry out the comparison research on OSC-HC deterioration tendency, of which one is problem sample and the other normal sample. The research targeted at the possible reasons of above- mentioned problems through lab fast aging test and performance test.
The tests show that the problem sample performs much worse than the normal sample on NO and C3H8 ‘s conversions. PM status and PM distribution on alumina substrate are speculated to lead the phenomenon. It is further considered that unreasonable catalyst design and matching lead to unachieved HC-OSC indexes, though special methods were taken for sample preparation and OBD calibration, OBD system can not play the normal on-board diagnosis function due to the obvious different deterioration tendency alumina.
