1.5 OBJECTIVEThe main challenge is how to reduce the hydrocarbon (HC) emitted from vehicles during the cold start. According to vehicle driving cycle tests, approximately 80% of HC is emitted in the cold start phase due to a low temperature of the exhaust gas and monolith. Therefore, how to increase HC conversion efficiency during the cold start is the key to satisfy the stringent regulations, and the temperature inside the monolith is the most important parameter to decrease the HC emission.