Abstract: An exhaust manifold for an internal combustion engine wherein exhaust ducts connected to respective engine cylinders are formed of discrete pipe members. A united section has an upstream divergent portion connected to the exhaust ducts and a downstream convergent portion to exhaust pipes. An internal space is defined in the downstream convergent portion and located intermediately between adjacent internal passages in the downstream convergent portion to communicate them with each other. An opening is formed in the peripheral wall of the downstream convergent portion at a location positionally corresponding to the internal space. A flange member has a boss formed thereon and being larger in size than the opening and disposed in face-to-face contact with an outer surface of the peripheral wall of the downstream convergent portion. The boss has a through bore formed therein and aligned with the opening, through which an exhaust constituent concentration sensor is to be inserted.

Abstract: A catalytic converter includes ring-shaped cushion members of differing bulk densities at each axial end of a catalyzer carrier, a first cushion member which is supported by a casing of the converter being of lesser bulk density than that of a second cushion member which is interposed between said first cushion member and the adjacent axial end of said catalyzer carrier.

Abstract: A device for supporting a cylindrical catalyst block includes a tubular cushion member mounted within a casing and encircling the catalyst block. An end member fixed within the casing carries an annular cushion. A ring is interposed between the annular cushion and the end face of the catalyst block. Interengaging parts are provided for preventing rotation of the ring with respect to the casing.

Abstract: The converter casing includes a hollow cylindrical body in which a monolithic catalyst substrate is supported by a wire-mesh cushioning element. Secured to the casing body are a pair of holding fixtures which are each fitted with an end cushioning element engageable with the adjacent end face of the catalyst substrate to hold the latter against axial displacement. The casing body includes a smaller-diameter portion, at least one larger-diameter portion and a sloped shoulder portion interposed therebetween. The holding fixtures are fixed to the larger-diameter or other end portions of the casing body in spaced relation to the cushioning element held between the catalyst substrate and the casing body. Such casing structure reduces the danger of the catalyst substrate being damaged or broken under vibration or shock to a minimum thereby to enhance the durability of the substrate and enables realization of a particularly compact and inexpensive catalytic converter.