Exhaust gas purifier with resistant circumferential sealing member between monolith catalyst and casing

Claim 1

A monolithic catalytic exhaust gas purifier for an internal combustion engine, the purifier including a cylindrical sheet metal casing having a longitudinal axis, a first end with an inlet, and a second end opposite the first end with an outlet for respectively introducing exhaust gas into and discharging exhaust gas from the casing, said casing having a flattened cross section transverse to said axis with a minimum cross dimension in one direction and a maximum cross dimension perpendicular to the one direction, a monolithic catalyst housed within the casing, and a supporting and sealing member of heat-insulating resilient material compressed within an annular space defined by the flattened cylindrical wall of the casing and an outer peripheral surface of the catalyst facing the flattened cylindrical wall of the casing, the supporting and sealing member existing completely around said outer peripheral circumference of the catalyst, wherein the improvement comprises: said monolithic catalyst being cylindrical and having a flattened cross section transverse to the longitudinal axis of the casing and having a minimum cross dimension and a maximum cross dimension; and said supporting and sealing member assembled completely around the catalyst having portions disposed at the minimum cross dimension of the catalyst and having a total thickness greater than the average thickness of the supporting and sealing member and portions disposed at the maximum cross dimension of the catalyst having a total thickness less than the average thickness of the supporting and sealing member, the thicker portions of the supporting and sealing member being disposed at the minimum cross dimension portion of the casing and the thinner portions being disposed at the maximum cross dimension portion of the casing such that the supporting and sealing member will maintain a bulk density balance over all portions of the member around the outer peripheral circumference of said catalyst when the exhaust gas purifier is heated to its normal operating temperature.