Advanced science.  Applied technology.


Engine Exhaust After-Treatment Device: 4,813,231


A diesel particulate trap formed from silicon carbide cermet foam with associated hardware to retain the foam in a particular configuration. Several pieces of the foam, in the shape of "doughnuts", are stacked on top of each other. The stack of foam doughnuts is assembled in a container designed to allow diesel exhaust to flow radially inward through the doughnuts and exit through the center. Ceramic felt gaskets are interposed between the doughnuts and between each of the end doughnuts and steel end plates. These gaskets serve as buffers and allow for different thermal expansion properties of the steel and silicon carbide cermet foam. The silicon carbide is conducting and has resistance and when current is passed through the foam doughnuts, they become hot enough to burn the collected particulate.

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Bruce B. Bykowski