Patent ID: 7393386

Claim:
An exhaust aftertreatment filter for filtering engine exhaust flowing along an axial flow direction, said filter being composed of regenerable material regenerated by heat to burn-off trapped contaminant particulate from said engine exhaust, said filter comprising a filter body having an outer periphery surrounding a central core, said outer periphery and said central core being subject to differential thermal expansion during thermal cycling during regeneration, due to said outer periphery being cooler than said central core, said differential thermal expansion subjecting said filter body to separational axial tensile stress in said axial direction which in turn subjects said filter body to separational fracture and cracking, and comprising a pre-stressed layer bonded to said filter body at said outer periphery and compressively axially pre-stressed in an opposite axial direction to said separational axial tensile stress to counteract the latter during regenerative heating.