Patent GB-441764-A (GB)
Title: Silencer for internal combustion engines
IPC: F01N3/05
Filed: 1934-07-20
Abstract: 441,764. Exhaust-silencers. TYDEN, E. O. E., 36, Hantverkaregatan, Stockholm. July 20, 1934, Nos. 21318, 21319, 21320, 21321, and 21322. Convention dates, Nov. 21, 1933, March 22, 1934, April 3, 1934, April 17, 1934, and May 4, 1934. [Class 7 (ii)] A silencer comprising a body or bodies located in the exhaust gas pipe and provided with a plurality of flow passages extending in or approximately in the longitudinal direction of the pipe, is characterized by said passages being made in such manner that the length of the passages is at least ten times their diameter or largest cross-sectional dimension, and the sum of their smallest cross-sectional areas is substantially smaller than the crosssectional area of the pipe so that a choking of the gases is effected. In Fig. 1, the passages 3 are formed in a body 2 of metal or other heat-resisting material secured in the pipe 1 some distance from its end. In a modification, Fig. 3 (not shown), the passages are inclined to the axis of the pipe. In Fig. 5, the passages are conical and are adapted to be controlled in area by conical pips 9 attached to a plate 10 adjustable by a wing screw 11. In a modification, Fig. 7 (not shown), the body is movable by the pressure of the gases against springs and the pins in the conical passages are fixed. In Fig. 9, two bodies 24, 22 are inserted in the pipe 21 with an intervening expansion chamber 26. The length of the passages 25 is approximately ten times and that of the passages 23 thirty times their diameter. In a modification, three bodies are arranged in the pipe with two intervening expansion chambers. The lengths of the passages in the respective bodies varying from ten to forty times their diameter and the sum of the cross-sectional areas of the passages in the body nearest the engine being smaller than that of either of the other two bodies. The body may comprise a number of uncontrolled conical passages Fig. 17, (not shown) or, as shown in Fig. 19, two such bodies 64, 62 may be employed with an intervening expansion chamber 66, the sum of the largest cross-sectional areas of the passages being larger than and the sum of the smallest crosssectional areas substantially smaller than the cross-sectional area of the exhaust pipe 61. In Fig. 22, the exhaust pipe 71 has an enlargement 72 which diminishes again to a part 73 somewhat larger than the exhaust pipe. Within the part 73 is a body comprising five tube concentric sections 74 separated by longitudinal ribs or ridges. This body is followed by a space 77 which, in turn, is followed by a body formed by bending a plate 78 into spiral form, the turns of the spiral being separated by wires or rods. In a modification, Fig. 25 (not shown), the passages are produced by a number of concentric cones of equal length, a cylindrical rod being provided in the innermost cone. In a construction, Fig. 26, intended for use in moving vehicles, the exhaust pipe 91 is widened at 92 to accommodate nests of tubes 95 secured by plates 96. Inlet apertures 97 and outlet apertures 98 are provided for air entering by the flared inlet 99. Between the nests of tubes is an expansion chamber 94. In a modification where cooling water is available, Fig. 28 (not shown), the part of the casing surrounding each nest of tubes has lateral inlet and outlet passages for cooling water which fills the spaces between the tubes.