Exhaust gas muffler

An exhaust gas muffler comprising a tubular envelope, a gas inlet at one end of said envelope, a gas outlet at the other end of said envelope, said ends of the tubular envelope being closed except for said gas inlet and outlet, at least one muffler insert between said ends including at least two spaced cones, the peripheral edge of each of said cones engaging the inner wall of said tubular envelopes at space locations, the axes of symmetry of said spaced apart cones being substantially co-axial to the central axis of said envelope, the apex of the front cone, as seen in the direction of flow, is inserted in the end cone, the latter being frustro-conical and co-axial with the other cone and directed in the same way, the narrowing part of said end cone opening into said gas outlet, and said end cone having at least one port opening into a front chamber defined by said end cone, said tubular envelope and the end wall of said envelope, a single relatively large gas flow passage in each of said cones, each of said gas flow passages having centers which are angularly separated from the centers of gas flow passages in adjacent cones, each of said inserts being disposed in said tubular envelope with the apices of the cones directed toward said outlet, said cones of each of said insert being so arranged with respect to spacing from one another such that the apex of the rearmost cone, as viewed in the direction of the gas flow, lies downstream of a plane perpendicular to the direction of the axis through the surface of abutment to the envelope of said front cone.