Internal combustion engine exhaust line muffler

Abstract

The internal combustion engine exhaust line muffler includes a casing; as well as, extending inside the casing, in the exhaust gas flow direction, from the upstream part and towards the downstream part of the casing, an exhaust gas intake pipe emerging inside the casing; and an evacuation pipe for the gas emerging into the atmosphere and having an upstream end located inside the casing. The muffler also includes, inside the casing, a device arranged to prevent, at least below a certain specific engine speed, penetration of exhaust gases into the evacuation pipe, through its upstream end; and an evacuation pipe portion provided with at least one perforation for penetration, into the pipe, of the exhaust gases from the intake pipe.

1 . Internal combustion engine exhaust line muffler comprising: 
 a casing;    an exhaust gas intake pipe, extending inside said casing, in an exhaust gas flow direction, from an upstream portion of said casing and towards a downstream portion of said casing and emerging inside said casing;    an exhaust gas evacuation pipe emerging into the atmosphere and being comprised of an upstream end located inside said casing;    a means to prevent penetration of exhaust gases, at least below a determined engine speed, into said evacuation pipe, through an upstream end thereof, the means to prevent being arranged inside said casing; and    an evacuation pipe portion comprised of at least one perforation for penetration, into said evacuation pipe, of the exhaust gases from the intake pipe.    
   
   
       2 . Muffler according to  claim 1 , wherein said evacuation pipe portion is further comprised of a plurality of perforations distributed, preferably regularly, at a periphery of said evacuation pipe.  
   
   
       3 . Muffler according to  claim 1 , wherein said evacuation pipe portion extends substantially along an axis, perforations in said evacuation pipe portion being provided according to another axis extending in a plane forming an angle with said axis.  
   
   
       4 . Muffler according to  claim 1 , wherein at least a perforated portion of said evacuation pipe extends substantially along an axis, perforations being provided for according to another axis extending in a radial direction with respect to said axis.  
   
   
       5 . Muffler according to  claim 1 , wherein said evacuation pipe portion is located in the upstream portion of said evacuation pipe, preferably in a vicinity of an upstream end of said evacuation pipe.  
   
   
       6 . Muffler according to  claim 1 , wherein said exhaust gases intake pipe emerges inside said casing through at least one opening provided for in a downstream portion of said intake pipe, preferably in a vicinity or at a level of a downstream end, located inside said casing and said intake pipe.  
   
   
       7 . Muffler according to  claim 1 , wherein said evacuation pipe further comprises: 
 at least at a level of the portion provided with at least one perforation, a means arranged to define at least one channel, emerging into an internal volume of said casing and communicating with the perforation or perforations of the evacuation pipe portion, the channel creating a counter-current exhaust gas flow with respect to a path of gases in said evacuation pipe, extending a path of said gases in said casing.    
   
   
       8 . Muffler according to  claim 7 , wherein the means arranged to define a channel is comprised of a sleeve, being a tubular and/or annular sleeve, arranged at least over said evacuation pipe portion.  
   
   
       9 . Muffler according to  claim 1 , wherein the means to prevent penetration of exhaust gases into said evacuation pipe are defined as to prevent, irrespective of engine speed, such a penetration of the gases.  
   
   
       10 . Muffler according to  claim 9 , wherein the means to prevent penetration of exhaust gases into said evacuation pipe, irrespective of engine speed, is further comprised of means for obturating said evacuation pipe, more particularly an upstream end of said evacuation pipe.  
   
   
       11 . Muffler according to  claim 9 , wherein said casing is subdivided by at least one tight dished plate, defining an upstream compartment and a downstream compartment; 
 wherein said intake pipe emerges, while said evacuation pipe extends through said downstream compartment and passes through said tight dished plate, so that the upstream end of said evacuation pipe is located inside said upstream compartment, said tight dished plate forming said means to prevent, irrespective of the engine speed, penetration of the exhaust gases into said evacuation pipe through an end thereof upstream.    
   
   
       12 . Muffler according to  claim 2 , wherein the means to prevent penetration of the exhaust gases into said evacuation pipe through an upstream end thereof, are defined so as to prevent, below a determined engine speed, such a penetration of these gases.  
   
   
       13 . Muffler according to  claim 12 , wherein the means, arranged for impeding, below said determined engine speed, to prevent penetration of the exhaust gases into the evacuation pipe through an upstream end thereof, comprises: 
 a valve associated with said upstream end and arranged to remain closed below said determined engine speed and to be open above said engine speed, authorizing the exhaust gases to flow into said evacuation pipe through an upstream end thereof.    
   
   
       14 . Muffler according to  claim 12 , wherein said casing is subdivided by at least one dished plate defining an upstream compartment and a downstream compartment, wherein said intake pipe emerges, while said evacuation pipe extends to through said downstream compartment and passes through said dished plate so that the upstream end of said evacuation pipe emerges inside said upstream compartment said dished plate being comprised of a valve arranged to remain closed below a determined engine speed and to be opened above said engine speed, authorizing said exhaust gases to flow from said downstream compartment into said upstream compartment, said valve and said dished plate forming said means arranged to prevent, below said determined engine speed, penetration of the exhaust gases into the evacuation pipe through an upstream end thereof.  
   
   
       15 . Muffler according to  claim 13 , wherein said valve is an overpressure valve of a self-controlled type.  
   
   
       16 . Muffler according to  claim 11 , said evacuation pipe portion provided with at least one perforation being located downstream from the dished plate and in a downstream compartment of said casing.