Method for control of washcoat distribution along channels of a particulate filter substrate

摘要

Disclosed herein is a method of distributing a washcoat along channels of a particulate filter substrate, the method including: forcing a washcoat slurry a predetermined distance into the channels, the predetermined distance being less than or equal to the full length of the channels; clearing an excess amount washcoat slurry from the channels; and arranging a remainder of the washcoat slurry within the channels, the arranging including applying a first vacuum to a first end of the particulate filter substrate after the clearing. In one embodiment the clearing includes applying a second vacuum to a second end of the particulate filter substrate. In another embodiment, the clearing includes pulling the excess washcoat slurry from the channels. The predetermined distance may be less than or equal to the full length of the channels. The arranging may provide a layer of a washcoat composition comprising a catalytically active material arranged anisotropically along a length of the channels of the particulate filter substrate.