The invention relates to flow altering valves for exhaust systems of motor vehicles.
Mufflers with variable damping characteristic are disclosed in U.S. Pat. No. 4,484,659; U.S. Pat. No. 5,614,669 or also U.S. 2002/0033303 A. All of these mufflers have a housing into which the exhaust gases of an internal combustion engine are passed by way of an inlet pipe and passed out by way of an outlet pipe. In the interior of the muffler housing, additional pipes are provided.
Further, in the interior of the muffler housing a valve is provided. This has a spring-loaded closure element, which in rest condition, i.e., at low gas flow rate, for example when the engine is idling, closes a gas port. This compels the exhaust gases to traverse a long distance, sharply damping noise interference, inside the muffler housing.
If the rotational speed of the internal combustion engine is increased, the flow of exhaust gas increases. Hence, a higher pressure acts on the closing element of the valve, so that it opens against the action of the spring. The exhaust gases flow through the opening, now clear, the pressure drop in the muffler housing recedes, and the engine power is increased.
U.S. Pat. No. 4,484,659 discloses several valve designs.
A first design employs a valve disk of spring steel, attached on one side.
A second design employs a valve disk attached to a tension spring.
The third design employs a swing flap attached by a membrane chamber whose control pressure is generated by a Venturi nozzle.
The fourth design employs a rotary slide moved by way of a membrane chamber whose control pressure is generated by a Venturi nozzle.
U.S. 2002/033303 A, as closure element, employs a flap, which is spring loaded.
U.S. Pat. No. 5,614,699 likewise employs a spring-loaded swing flap.
Since in all these designs the valve is accommodated in the interior of the muffler housing, all its parts are exposed to the heat, the aggressive elements and the pressure pulsations of the exhaust gas. The several parts must therefore be made of temperature-resistant and oxidation-free material. Therefore these designs have failed to find acceptance in practice.
A valve adaptable for use in altering fluid flow in an exhaust system has a movable member including a valve disk, and an assembly element enabling the valve to be mounted to the exhaust system in a manner such that the valve disk is located substantially parallel to and facing an open end of a preselected fluid conduit of the exhaust system, the disk being movable along an axis of the open end to vary fluid flow at the open end.
The essential advantage of the present invention is based on the fact that the valve housing in which the temperature-sensitive spring is accommodated is positioned outside of the muffler housing. The hot exhaust gases cannot directly heat the valve housing. Furthermore, the valve housing is cooled by the airstream. Since the valve housing is gastight and connected gastight to the muffler housing, no exhaust gases can escape.
With reference to the drawings, the invention will be illustrated in more detail in the form of an embodiment by way of example. In each instance quite schematically,
In the interior of the housing 20, three pipes 1, 1′, 1″ carrying gas are seen. The pipe 1 has a perforation 26, through which the gases can escape, in the neighborhood of the first chamber 23.
As
Between the spring guide disk 7 and the valve housing 10, a ring 6 of wire knit is placed on the guide rod 4. This ring 6 serves as damping element and prevents noise interference.
As
As soon as the rotational speed of the internal combustion engine (not shown) increases, the quantity of exhaust gas flowing in through the pipe 27 into the muffler housing 20 increases. This increases the jet impact on the valve disk 3. As soon as the pressure is high enough, the valve disk 3 opens against the force of the spring 8 and clears the way for the exhaust gases. This is shown in
The entire disclosure of German Patent Application No. 10311201.4 filed Mar. 14, 2003, is incorporated by reference.
Number | Date | Country | Kind |
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10311201.4 | Mar 2003 | DE | national |
This application is a continuation of U.S. patent application Ser. No. 10/677,554, filed Oct. 2, 2003.
Number | Date | Country | |
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Parent | 10677554 | Oct 2003 | US |
Child | 10984709 | Nov 2004 | US |