Exhaust cleaner for IC engine of motor vehicle - has porous silicon-carbide filter in thermally insulating mounting for burning off carbon deposits

The exhaust gases are ducted through a special filter composed of porous silicon carbide (5) to remove carbon particles and unburnt fuel. The filter is surrounded by a shell of thermal insulation, with openings fore and aft for the flow and mounted inside a housing. The good thermal conductivity of the silicon carbide ensures rapid burn of the carbon when the integral electric heating element is powered. The heating can be by direct electric element, microwave heating or hot gas heating. The filter element has a pore size 20 to 30 microns and a density of 1.7 to 1.9 gm/sq.cm. The filter size has a diameter to length ratio of 5 to 70, and a surface area to volume ratio of 0.2 to 0.5. ADVANTAGE - Rapid carbon reduction, minimal thermal losses.