Catalytic emission control systems are installed on nearly all
automobiles and heavy-duty trucks produced today to reduce exhaust
emissions for the vehicles to meet government regulations. Current
systems can achieve very high efficiencies in reducing tailpipe
emissions once the catalytic components reach their operating
temperatures. They are, however, relatively ineffective at
temperatures below their operating temperature windows, especially
during the cold start period of the vehicles. With the increasingly
stringent government regulations, reducing the emissions during the
cold start period before the catalytic components reach their
operating temperatures is becoming a major challenge.
For cold start HC control, HC traps based on zeolites have been
investigated and commercialized for certain applications. For cold
start NOx control, especially in lean burn engine exhaust, NOx
storage and release catalysts have been evaluated. In this paper we
will introduce a novel catalyst which we refer to as Cold Start
Concept (CSC™) catalyst technology. This cold start catalyst not
only stores HC and NOx at low temperatures with very high storage
efficiencies, but also converts a significant portion of the stored
HC/NOx during the warm-up period before the rest of the HC/NOx is
thermally released from the catalyst. The HC/NOx release
temperature in a cold start catalyst is high enough that the
released HC/NOx can be further converted by the downstream
catalytic components. In addition, the cold start catalyst also
exhibits excellent CO, HC, and NO oxidation activity under normal
lean conditions. Both laboratory and engine evaluation results of
this new concept will be presented.