Exhaust system for internal combustion engine

Abstract

An exhaust system that can be assembled easily. A catalytic converter comprises a first flange, and a filter unit comprises a second flange joined to the first flange. A bracket is formed integrally with the first flange, and a through hole is formed in the bracket. One end of a first downstream pipe is connected to the filter unit, and one end of a second downstream pipe is connected to the differential pressure detector. The other end of the first downstream pipe and the other end of the second downstream pipe are held by the bracket and communicated with each other through the through hole of the bracket. A portion of the catalytic converter upstream of the first flange is connected to the differential pressure detector through an upstream pipe.

What is claimed is: 
     
         1 . An exhaust system for an internal combustion engine, comprising:
 a catalytic converter that performs an oxidation reaction or a reduction reaction to remove pollutants from an exhaust gas resulting from a combustion of the engine and flowing therethrough;   a filter unit that is joined to a downstream side of the catalytic converter to capture particulate matter contained in the exhaust gas; and   a differential pressure detector that detects a difference between a pressure of the exhaust gas flowing upstream of the filter unit and a pressure of the exhaust gas flowing downstream of the filter unit,   wherein the catalytic converter comprises a first flange as a connection member,   the filter unit comprises a second flange that is joined to the first flange of the catalytic converter,   the catalytic converter further comprises a bracket in which a through hole is formed,   the exhaust system further comprises a first downstream pipe in which one end thereof is connected to a downstream section of the filter unit, and a second downstream pipe in which one end thereof is connected to the differential pressure detector,   the other end of the first downstream pipe and the other end of the second downstream pipe are held by the bracket and communicated with each other through the through hole of the bracket, and   the exhaust system further comprises an upstream pipe that connects a portion of the catalytic converter upstream of the first flange to the differential pressure detector.   
     
     
         2 . The exhaust system for the internal combustion engine as claimed in  claim 1 ,
 wherein the through hole comprises a first opening that opens toward the filter unit and a second opening that opens toward the catalytic converter,   the other end of the first downstream pipe is pushed onto the first opening to be communicated with the first opening, and   the other end of the second downstream pipe is fixed to the bracket while being communicated with the second opening.   
     
     
         3 . The exhaust system for the internal combustion engine as claimed in  claim 2 , further comprising:
 a plate member that pushes the other end of the first downstream pipe onto the first opening,   wherein the plate member is attached to the second flange in a detachable manner.   
     
     
         4 . The exhaust system for the internal combustion engine as claimed in  claim 3 ,
 wherein the plate member is formed of flexible material, and   the exhaust system further comprises a protrusion formed on the first downstream pipe that is in contact with the plate member to be pushed by the plate member.   
     
     
         5 . The exhaust system for the internal combustion engine as claimed in  claim 3 ,
 wherein the first downstream pipe penetrates through the plate member, and   the exhaust system further comprises
 a protrusion that is formed on the first downstream pipe to be opposed to the plate member, and 
 an elastic member that is interposed between the protrusion and the plate member to push the first downstream pipe in a direction that the other end of the first downstream pipe is pushed onto the first opening. 
   
     
     
         6 . The exhaust system for the internal combustion engine as claimed in  claim 3 , further comprising:
 a cylindrical member that is attached to an outer circumference of the other end of the first downstream pipe,   wherein the plate member is adapted to push the cylindrical member toward the bracket, and   a sealing member is interposed between the cylindrical member and the bracket.   
     
     
         7 . The exhaust system for the internal combustion engine as claimed in  claim 2 ,
 wherein a circumferential edge of the first opening is shaped into a concave spherical receiving surface, and   the other end of the first downstream pipe is shaped into a spherical convex curve.   
     
     
         8 . The exhaust system for the internal combustion engine as claimed in  claim 3 ,
 wherein a circumferential edge of the first opening is shaped into a concave spherical receiving surface, and   the other end of the first downstream pipe is shaped into a spherical convex curve.   
     
     
         9 . The exhaust system for the internal combustion engine as claimed in  claim 4 ,
 wherein a circumferential edge of the first opening is shaped into a concave spherical receiving surface, and   the other end of the first downstream pipe is shaped into a spherical convex curve.   
     
     
         10 . The exhaust system for the internal combustion engine as claimed in  claim 5 ,
 wherein a circumferential edge of the first opening is shaped into a concave spherical receiving surface, and   the other end of the first downstream pipe is shaped into a spherical convex curve.   
     
     
         11 . The exhaust system for the internal combustion engine as claimed in 
     
     
         7 . wherein a sealing member is interposed between the concave spherical receiving surface and the spherical convex curve. 
     
     
         12 . The exhaust system for the internal combustion engine as claimed in  claim 8 , wherein a sealing member is interposed between the concave spherical receiving surface and the spherical convex curve. 
     
     
         13 . The exhaust system for the internal combustion engine as claimed in  claim 9 , wherein a sealing member is interposed between the concave spherical receiving surface and the spherical convex curve. 
     
     
         14 . The exhaust system for the internal combustion engine as claimed in  claim 10 , wherein a sealing member is interposed between the concave spherical receiving surface and the spherical convex curve.