Patent Publication Number: US-2002005318-A1

Title: Valve in an exhaust gas muffler device of a motor vehicle

Description:
CROSS-REFERENCES TO RELATED APPLICATION  
       [0001] Not applicable.  
       STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
       [0002] Not applicable.  
       BACKGROUND OF THE INVENTION  
       [0003] The invention relates to a valve in an exhaust gas muffler device of a motor vehicle with housing opening conducting exhaust gas and connecting the interior of a housing of the muffler device to outward of said housing.  
       TECHNICAL FIELD  
       [0004] Known exhaust gas mufflers partially comprise muffler housings with at least two exhaust gas discharge openings, one of which can be intermittently shut off by a valve from passage of exhaust gas. A valve is known in this connection which is constituted outward of the housing as a flap valve in a pipe leading out of the related opening of the housing and pivotable perpendicularly of the pipe axis. The opening through which the flow of exhaust gas is prevented is situated within the muffler housing, on an end of this pipe projecting into the interior of the housing. The intermittent closing of, for example, one of two openings leading out of a muffler housing takes place in practice for the improvement of the noise damping which can be attained in the muffler housing with respect to the different quantitative flows of exhaust gas according to the engine operation. Thus, for example, a motor vehicle muffler with two outlet pipes attains a marked acoustic improvement in the low frequency noise region by the closing of one of these two pipes.  
       SUMMARY OF THE INVENTION  
       [0005] The invention has as its object to provide a valve of the category concerned, with a simple and functionally reliable construction.  
       [0006] This object is attained by the embodiment of a valve of the category concerned wherein one of the housing openings can be closed with a closure element situated within the housing and displaceably mounted on the housing, when the one housing opening is closed, the closure element sealingly abuts on an edge of the one housing opening to be closed.  
       [0007] The invention is based on the general concept of embodying a valve of the category concerned in a simple manner, in that the movable closure element of a valve is a closure element which is mounted to be displaceable perpendicularly of the plane of the opening to be closed and which can be pushed against the opening to close it.  
       [0008] The displacement can take place by means of a servomotor or positioning motor, for example mounted on the outside of the muffler housing. The valve closure element can then be connected to the servomotor or positioning motor by means of a rod-shaped element.  
       [0009] In an economic production of a muffler housing with a valve of the category concerned, production tolerances as a rule arise which prevent a close seating of the closure element on the opening in the closed state of the valve, when there is a rigid fastening of the closure element to a positioning element going out from the servomotor or positioning motor. These production tolerances cannot, in most cases, be compensated for by elastic sealing means on the contact surfaces between the closure element and the opening to be closed. This particularly depends on the fact that such elastic sealing materials are not available for the high temperatures present in the exhaust gas passing through a muffler.  
       [0010] Tolerance-compensating elastic regions are provided in a coupling between the closure element and the positioning motor, and provide an embodiment with which reliable closure conditions of the valve are attainable even when there are relatively large production irregularities. This is attained by means of the tolerance-compensating elastic regions inserted as the adjusting element of the servomotor or positioning motor in the coupling to the closure element.  
       [0011] These tolerance-compensating regions can consist of elastically resilient, i.e., deformable, metal mesh or metal mesh fabric. Such metal mesh fabrics can per se durably withstand the high exhaust gas temperatures.  
       [0012] The metal mesh fabrics can be embodied practically impermeable to flow, which is important when they are situated in valve regions through which exhaust gases could flow when the valve is closed. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0013] Embodiment examples of the invention are shown in the drawing.  
     [0014]FIG. 1 shows a schematic diagram of a muffler housing of an exhaust gas device with two exhaust gas outlet openings.  
     [0015]FIGS. 2 and 3 show alternative constitutions of the valve region denoted by II, III in FIG. 1. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
     [0016] In the muffler housing  1  according to FIG. 1, an exhaust gas inlet and two exhaust gas outlets are provided, and are in fact respective pipes projecting into the interior of the muffler housing  1  and leading out of the housing, namely an inlet pipe  2  and also outlet pipes  3  and  4 .  
     [0017] The exhaust gas flows via the inlet pipe  2  into the housing interior through perforations  5  provided in the portion of the inlet pipe  2  situated in the interior of the housing  1 .  
     [0018] Of the outlet pipes, the outlet pipe  4  can be closed by a valve  6 .  
     [0019] This valve  6  consists of the end opening, situated in the interior of the muffler housing  1 , of the outlet pipe  4 , as a valve seating, and a closure plate  7 , which is displaceable along the pipe axis and thus perpendicularly of the opening of the pipe  4 . The closure plate  7  of the valve  6  is connected via a connecting rod  8  to a servomotor or positioning motor  9  which is installed on the outside of the muffler housing.  
     [0020] The opening of the outlet pipe  4  can be opened and closed in a simple manner by displacement of the closure plate  7  by means of the servomotor or positioning motor  9 . In the drawing, the valve  6  is shown in the closed state by full lines and in the opened state by dashed lines. The inflow and discharge of exhaust gas through the muffler housing are indicated by flow arrows.  
     [0021] Special constitutions of the closure plate  7  and of its fastening to the connecting rod  8  are shown in FIGS. 2 and 3.  
     [0022] In the embodiment according to FIG. 2, an annular disk  10 , for example of metal, is provided in the radially outer region of the closure plate  7 . This annular disk  10  is connected by means of a doubled metal mesh fabric packing to the connecting rod  8  leading to the servomotor.  
     [0023] These metal mesh fabric packings  11  and  12  axially enclose the inner edge of the annular disk  10  between them. With a tubular constitution of the connecting rod  8 , the fastening of the two metal mesh fabric packings  11  and  12  which axially enclose the annular disk  10  between them takes place by means of a rivet  18  pressed into the tubular cavity of the connecting rod  8  and with its head supported on one of the metal mesh fabric packings  11 ,  12 , the metal mesh fabric packing  11  remote from the rivet head being pressed against an annular flange  14  provided on the connecting rod  8 .  
     [0024] A metal mesh fabric sealing ring  13  is provided at the outer edge of the annular disk  10 , in the region contacting the exhaust gas outlet pipe  4  at the end. Instead of the metal mesh fabric material, any other elastically resilient, sufficiently temperature-resistant sealing material can of course be used in the sealing ring  13 . The same holds in principle for the metal mesh fabric packings  11 ,  12 , as long as the material concerned is elastically resilient and sufficiently temperature-resistant with respect to its use in the muffler of an exhaust gas device. The sealing ring  13  can be fixed by a fold  17  rolled onto the annular disk  10 .  
     [0025] The embodiment according to FIG. 3 differs from that according to FIG. 2 solely in the manner of clamping the metal mesh fabric packings  11  and  12  to the connecting rod  8 . The clamping according to FIG. 3 takes place by means of flanges  15  and  16  formed, particularly rolled, on the tubular connecting rod  8 . The flange  16  thus replaces the rivet head and the flange  15  replaces the annular flange  14  of the embodiment according to FIG. 2.  
     [0026] With the metal mesh fabric inserts  11 ,  12  and  13 , angular misalignments of the closure plate  7  with respect to the opening edge of the outlet pipe  4  arising during manufacture can be compensated for to the extent of about 3 to 4 degrees of angle without further measures. In the case of a possible incomplete flow-tightness of the metal mesh fabric inserts  11 ,  12 ,  13 , it can happen that very small amounts of exhaust gas, not functionally troublesome, pass through these knitted fabric regions. Such leakage exhaust gas streams when the valve is closed can be suppressed practically completely by an impregnation with, for example, graphite.