초록 ▼

A silencer that comprises a casing, one or more pipes or passages leading a flow of gas to the casing and a device for leading gas from the casing. The silencer further has at least one internal chamber, one or more flow inlets to the chamber and one or more flow outlets from the chamber, and one or

A silencer that comprises a casing, one or more pipes or passages leading a flow of gas to the casing and a device for leading gas from the casing. The silencer further has at least one internal chamber, one or more flow inlets to the chamber and one or more flow outlets from the chamber, and one or more flow distributing devices connected to the flow inlet(s) and/or to the flow outlet(s). The flow distributing device comprises one or more walls or profiles extending on a geometrical surface that defines a boundary between an inner volume of the flow distributing device and the chamber. The silencer further has one or more apertures for a flow of gas through the apertures and for leading gas either out of the inner volume into the chamber, or into the inner volume from the chamber. The apertures have a smallest cross-sectional transverse dimension s and a length L, the dimension s being at the maximum 0.2 times the smallest cross-sectional dimension D of the inlet or outlet. The length L is at least the same as the dimension s.

대표청구항 ▼

The invention claimed is: 1. A silencer comprising a casing, one or more pipes or passages leading a flow of gas to said casing and means for leading gas from said casing, the silencer further comprising at least one internal chamber, one or more flow inlets to said chamber and one or more flow out

The invention claimed is: 1. A silencer comprising a casing, one or more pipes or passages leading a flow of gas to said casing and means for leading gas from said casing, the silencer further comprising at least one internal chamber, one or more flow inlets to said chamber and one or more flow outlets from said chamber, and one or more flow distributing means connected to at least one of said one or more flow inlet and to said one or more flow outlet, said flow distributing means comprising one or more walls or profiles extending on a geometrical surface defining a boundary between an inner volume of said flow distributing means and said chamber, and one or more apertures for a flow of gas through said apertures and for leading gas either out of said inner volume into said chamber, or into said inner volume from said chamber, said apertures having a smallest cross-sectional transverse dimension s and a length L, said dimension s being at the maximum 0.2 times the smallest cross-sectional dimension D of the inlet or outlet to which the flow distributing means is connected, and said length L being at least the same as said dimension s, whereby said one or more aperture are formed so as to provide a flow-area widening in flow direction along at least part of the aperture length L, and wherein substantial pressure recovery takes place within said one or more aperture. 2. The silencer according to claim 1, wherein said geometrical surface extends in an axial direction and has an axial length which is at least twice said smallest cross-sectional dimension D. 3. The silencer according to claim 1, wherein said geometrical surface extends in an axial direction and has an axial length which is at least four times said smallest cross-sectional dimension D. 4. The silencer according to claim 1, wherein said walls or profiles form a tube across which gas passes through said apertures. 5. The silencer according to claim 4, wherein said walls or profiles are adapted to be through-flowed at one or more positions around at least 180 degrees of the periphery of said tube. 6. The silencer according to claim 1, wherein said dimension s is at the most 0.1 times said dimension D. 7. The silencer according to claim 1, wherein said dimension s is at the most 0.05 times said dimension D. 8. The silencer according to claim 1, wherein said length L is at least twice said dimension s. 9. The silencer according to claim 1, wherein said length L is at least four times said dimension s. 10. The silencer according to claim 1, wherein the inflow to said apertures is provided with flow-separation preventing rounding of contours or is otherwise formed so as to cause gradually decreasing flow cross-section at the inlet to said apertures. 11. The silencer according to claim 1, wherein said flow distributing means are adapted to lead gas to a silencer chamber. 12. The silencer according to claim 1, wherein said flow distributing means are adapted to lead gas from a silencer chamber. 13. The silencer according to claim 1, wherein the minimum total flow cross-sectional area of said apertures is a factor f times the cross-sectional area of the inlet or outlet to which said flow distributing means is connected, said factor f being at the most 1.3 and at the least 0.7. 14. The silencer according to claim 13, wherein said factor f is between 0.9 and 1.1. 15. The silencer according to claim 1, wherein a flow-area narrowing passage part precedes said flow-area widening part when seen in said flow direction. 16. The silencer according to claim 1, wherein said flow-area widening is gradual. 17. The silencer according to claim 15, wherein said flow-area widening is so small that no major flow separation may occur within said one or more aperture. 18. The silencer according to claim 15, wherein flow separation may occur within said one or more aperture. 19. The silencer according to claim 1, wherein said one or more aperture are formed so as to maximise pressure recovery within said one or more aperture. 20. The silencer according to claim 1, wherein the cross-sectional area within said one or more aperture are substantially constant. 21. The silencer according to claim 4, wherein the flow direction within said one or more aperture are substantially transverse to the overall flow direction within said tube. 22. The silencer according to claim 4, wherein the flow direction within said one or more aperture are substantially aligned with the overall flow direction within said tube. 23. The silencer according to claim 1, wherein said apertures are separate holes. 24. The silencer according to claim 1, wherein said apertures comprise at least two slots. 25. The silencer according to claim 24, wherein said apertures are formed between substantially rotational symmetrical tube members. 26. The silencer according to claim 25, wherein said tube members are substantially identical. 27. The silencer according to claim 25, wherein the size of said tube members decreases in the flow direction in case of said flow distributing means being connected to a chamber inlet, and the size of said tube members increases in the flow direction in case of said flow distributing means being connected to a chamber outlet. 28. The silencer according to claim 26, wherein a central conical member is inserted into said flow distributing means. 29. The silencer according to claim 4, wherein said apertures are formed as slots between substantially identical members, each of said members covering an angular segment of said tube. 30. The silencer according to claim 29, wherein the flow direction through said slots is radial. 31. The silencer according to claim 4, wherein a helically winding element forms said tube, and said aperture is formed as a helically winding slot between the windings of said winding element. 32. The silencer according to claim 28, wherein said tube decreases in diameter in the flow direction in case of said tube being connected to a chamber inlet, and said tube increases in diameter in case of said tube being connected to a chamber outlet. 33. The silencer according to claim 3, wherein said tube is terminated by a closed end. 34. The silencer according to claim 3, wherein said tube is terminated by a wall with apertures. 35. The silencer according to claim 3, wherein said tube is terminated by an open end. 36. The silencer according to claim 35, wherein said open end is formed as a diffuser. 37. The silencer according to claim 1 and further comprising means for applying the silencer to the engine system of a vehicle. 38. The silencer according to claim 1, further comprising one or more monoliths being at least one of filters and catalytic converters. 39. The silencer according to claim 38, wherein one or more of said flow distributing members is/are arranged upstream of one or more of said monoliths. 40. A vehicle comprising an engine and a silencer according to claim 1. 41. A method of at least one of reducing the pressure drop across a silencer and improving attenuation conferred by the silencer, the method comprising the step of replacing one or more perforated pipe members in said silencer with one or more flow distributing elements, said flow distributing elements comprising one or more walls or profiles extending on a geometrical surface defining a boundary between an inner volume of said flow distributing elements and a chamber of the silencer, and one or more apertures for a flow of gas and for leading gas either out of said inner volume into said chamber, or into said inner volume from said chamber, said apertures having a smallest cross-sectional transverse dimension s and a length L, said dimension s being at the maximum 0.2 times the smallest cross-sectional dimension D of the inlet or outlet to which the flow distributing means is connected, and said length L being at least the same as said dimension s, whereby said aperture are formed so as to provide a flow-area widening in flow direction along at least part of the aperture length L, and wherein substantial pressure recovery takes place within said one or more aperture.