Variable geometry muffler for an exhaust system of an internal combustion engine

Abstract

A variable geometry muffler for an exhaust system of an internal combustion engine; the muffler displays: a tubular body, which displays an inlet opening, an outlet opening and a labyrinth which determines a path for the exhaust gases from the inlet opening to the outlet opening; and a bypass valve, which is arranged within the tubular body to modify the geometry of the labyrinth according to the exhaust gas pressure; the bypass valve displays a lid, which is coupled to a bypass opening and is mobile from a closed position of the bypass opening to an opening position of the bypass opening by effect of the exhaust gas pressure and against the bias of an elastic body which tends to maintain the lid in the closed position; the elastic body consists of an elastic foil, which is folded as a “U” and displays a mobile end which supports the lid and a fixed end which is opposite to the mobile end and which is integral with a fixed part of the muffler.

1 ) A variable geometry muffler ( 1 ) for an exhaust system of an internal combustion engine; the muffler ( 1 ) comprises:
 a tubular body ( 2 ), which displays an inlet opening ( 3 ), an outlet opening ( 4 ) and a labyrinth ( 5 ) which determines a path for the exhaust gases from the inlet opening ( 3 ) to the outlet opening ( 4 ); and   at least one bypass valve ( 10 ), which is arranged within the tubular body ( 2 ) to modify the geometry of the labyrinth ( 5 ) according to the exhaust gas pressure;   the bypass valve ( 10 ) comprising a lid ( 11 ), which is coupled to a bypass opening ( 12 ) and is mobile from a closed position of the bypass opening ( 12 ) to an opening position of the bypass opening ( 12 ) by effect of the exhaust gas pressure and against the bias of an elastic body which tends to maintain the lid ( 11 ) in the closed position;   the muffler ( 1 ) is characterised in that the elastic body consists of an elastic foil ( 13 ), which is folded as a “U” and displays a mobile end ( 14 ) coupled to the lid ( 11 ) and a fixed end ( 15 ) which is opposite to the mobile end ( 14 ) and integral with a fixed part of the muffler ( 1 ).   
   
   
       2 ) A muffler ( 1 ) according to  claim 1 , wherein the mobile end ( 14 ) of the elastic foil ( 13 ) supports the lid ( 11 ). 
   
   
       3 ) A muffler ( 1 ) according to  claim 2 , wherein the mobile end ( 14 ) of the elastic foil ( 13 ) supports the lid ( 11 ) by means of the interposition of a connecting element, which is fixed both to the mobile end ( 14 ) and to the lid ( 11 ). 
   
   
       4 ) A muffler ( 1 ) according to  claim 1 , wherein the fixed end ( 15 ) of the elastic foil ( 13 ) is arranged by the side of the bypass opening ( 12 ). 
   
   
       5 ) A muffler ( 1 ) according to  claim 4 , wherein the fixed end ( 15 ) of elastic foil ( 13 ) is fixed to a support ( 16 ), which is fixed to a fixed part of the muffler ( 1 ), is arranged over the bypass opening ( 12 ) and displays a through hole ( 17 ) obtained at bypass opening ( 12 ) itself. 
   
   
       6 ) A muffler ( 1 ) according to  claim 1 , wherein the lid ( 11 ) consists of an extension of the mobile end ( 14 ) of the elastic foil ( 13 ) and forms a monolithic body with the elastic foil ( 13 ) itself. 
   
   
       7 ) A muffler ( 1 ) according to  claim 1 , wherein the mobile end ( 14 ) of the elastic foil ( 13 ) is directly fixed to the lid ( 11 ) and the fixed end ( 15 ) of the elastic foil ( 13 ) is fixed to a support ( 16 ) fixed onto a fixed part of the muffler ( 1 ). 
   
   
       8 ) A muffler ( 1 ) according to  claim 7 , wherein the support ( 16 ) is shaped as an inverted “U”. 
   
   
       9 ) A muffler ( 1 ) according to  claim 1 , wherein the lid ( 11 ) is hinged to a fixed part of the muffler ( 1 ) and the mobile end ( 14 ) of the elastic foil ( 13 ) rests on the lid ( 11 ). 
   
   
       10 ) A muffler ( 1 ) according to  claim 9 , wherein a support ( 16 ), which is integral with a fixed part of the muffler ( 1 ), accommodates the fixed end ( 15 ) of the elastic foil ( 13 ), and supports a hinging pin ( 18 ) of the lid ( 11 ), is provided. 
   
   
       11 ) A muffler ( 1 ) according to  claim 10 , wherein the pin ( 18 ) is integral with the support ( 16 ) and the lid ( 11 ) turns with respect to the pin ( 18 ). 
   
   
       12 ) A muffler ( 1 ) according to  claim 10 , wherein the pin ( 18 ) is integral with the lid ( 11 ) and turns with respect to the support ( 16 ). 
   
   
       13 ) A muffler ( 1 ) according to  claim 10 , wherein the elastic foil ( 13 ) partially envelops the pin ( 18 ). 
   
   
       14 ) A muffler ( 1 ) according to  claim 1 , wherein the bypass valve ( 10 ) comprises a wire-mesh ring ( 19 ), which is arranged about the bypass opening ( 12 ) to define an abutting element against which the lid ( 11 ) rests in the closed position. 
   
   
       15 ) A muffler ( 1 ) according to  claim 14 , wherein the bypass opening ( 12 ) is obtained through a diaphragm ( 6 ), which displays an annular accommodation seat ( 20 ) of the wire-mesh ring ( 19 ). 
   
   
       16 ) A muffler ( 1 ) according to  claim 15 , wherein the wire-mesh ring ( 19 ) displays a rectangular section;
 the accommodation seat ( 20 ) consists of a “U”-shaped fold of the diaphragm ( 6 ) squashed to clamp a lower portion of the wire-mesh ring ( 19 ).   
   
   
       17 ) A muffler ( 1 ) according to  claim 15 , wherein the wire-mesh ring ( 19 ) displays an “L”-shaped section;
 the accommodation seat ( 20 ) consists of a plurality of portions of the diaphragm ( 6 ) each of which is arranged to delimit the bypass opening ( 12 ) and is deformed to catch a lower horizontal portion of the wire-mesh ring ( 19 ).   
   
   
       18 ) A muffler ( 1 ) according to  claim 17 , wherein the portions ( 21 ) of the diaphragm ( 6 ) are alternatively deformed in opposite directions to catch opposite sides of the horizontal portion of the wire-mesh ring ( 19 ). 
   
   
       19 ) A variable geometry muffler ( 1 ) for an exhaust system of an internal combustion engine; the muffler ( 1 ) comprises:
 a tubular body ( 2 ), which displays an inlet opening ( 3 ), an outlet opening ( 4 ) and a labyrinth ( 5 ) which determines a path for the exhaust gases from the inlet opening ( 3 ) to the outlet opening ( 4 ); and   one bypass valve ( 10 ), which is arranged within the tubular body ( 2 ) to modify the geometry of the labyrinth ( 5 ) according to the exhaust gas pressure;   the bypass valve ( 10 ) comprises a lid ( 11 ), which is coupled to a bypass opening ( 12 ) obtained through a diaphragm ( 6 ) and is mobile from a closed position of the bypass opening ( 12 ) to an opening position of the bypass opening ( 12 ) by effect of the exhaust gas pressure and against the bias of an elastic body which tends to maintain the lid ( 11 ) in the closed position, and a wire-mesh ring ( 19 ), which displays an “L”-shaped section and which is arranged about the bypass opening ( 12 ) to define an abutting element against which the lid ( 11 ) rests in the closed position;   the muffler ( 1 ) is characterised in that the diaphragm ( 6 ) displays an annular accommodation seat ( 20 ) of the wire-mesh ring ( 19 ) formed by a plurality of portions ( 21 ) of the diaphragm ( 6 ), each of which is arranged to delimit the bypass aperture ( 12 ) and is deformed to catch a horizontal portion of the wire-mesh ring ( 19 ).   
   
   
       20 ) A muffler ( 1 ) according to  claim 19 , wherein the portions ( 21 ) of the diaphragm ( 6 ) are alternatively deformed in opposite directions to catch opposite sides of the horizontal portion of the wire-mesh ring ( 19 ).