Exhaust system for internal combustion engine

Abstract

The present disclosure provides an exhaust system for an internal combustion engine, the exhaust system comprising a first exhaust pipe, a muffler and a second exhaust pipe, and the muffler is mounted between the first exhaust pipe and the second exhaust pipe, the first exhaust pipe is located upstream of the muffler, and the second exhaust pipe is located downstream of the muffler; the second exhaust pipe comprises a single exhaust pipe, the single exhaust pipe having one end connected to a downstream end of the muffler, and the single exhaust pipe being provided with a plurality of connecting holes; or, the second exhaust pipe comprises the single exhaust pipe and a dual exhaust pipe branch, the single exhaust pipe having one end connected to the downstream end of the muffler and the other end connected to the dual exhaust pipe branch.

What is claimed is: 
     
         1 . An exhaust system for an internal combustion engine, comprising: a first exhaust pipe, a muffler and a second exhaust pipe, wherein the muffler is mounted between the first exhaust pipe and the second exhaust pipe, the first exhaust pipe is located upstream of the muffler, and the second exhaust pipe is located downstream of the muffler;
 the second exhaust pipe comprises a single exhaust pipe, the single exhaust pipe having a first end connected to a downstream end of the muffler, and the single exhaust pipe being provided with a plurality of connecting holes; or   the second exhaust pipe comprises the single exhaust pipe and a dual exhaust pipe branch, the single exhaust pipe having the first end connected to the downstream end of the muffler and a second end connected to the dual exhaust pipe branch, and the single exhaust pipe and the dual exhaust pipe branch being respectively provided with a plurality of connecting holes.   
     
     
         2 . The exhaust system for an internal combustion engine of  claim 1 , wherein the second exhaust pipe has a length greater than 1 meter. 
     
     
         3 . The exhaust system for an internal combustion engine of  claim 1 , wherein a connecting hole is a round hole, and the total equivalent area of the round hole is greater than or equal to that of a round hole with a diameter of 2 mm and smaller than that of a round hole with a diameter of 30 mm. 
     
     
         4 . The exhaust system for an internal combustion engine of  claim 1 , wherein a connecting hole is a rectangular hole, and the total equivalent area of the rectangular hole is greater than or equal to that of a round hole with a diameter of 2 mm and smaller than that of a round hole with a diameter of 30 mm. 
     
     
         5 . The exhaust system for an internal combustion engine of  claim 1 , wherein a connecting hole is of a micro-perforation structure, and the total equivalent area of the micro-perforation structure is greater than or equal to that of a round hole with a diameter of 2 mm and smaller than that of a round hole with a diameter of 30 mm. 
     
     
         6 . The exhaust system for an internal combustion engine of  claim 1 , wherein an external heat shield is arranged on the connecting hole, the external heat shield is an enclosed heat shield or a heat shield provided with an open pore, and the total equivalent area of the open pore is greater than or equal to that of a round hole with a diameter of 2 mm and smaller than that of a round hole with a diameter of 30 mm. 
     
     
         7 . The exhaust system for an internal combustion engine of  claim 1 , wherein a Helmholtz resonator is provided on the connecting hole, and the Helmholtz resonator has a volume smaller than or equal to 1 L. 
     
     
         8 . The exhaust system for an internal combustion engine of  claim 7 , wherein the Helmholtz resonator is provided in a form of a neck patch, a neck pipe or other transfer passage. 
     
     
         9 . The exhaust system for an internal combustion engine of  claim 1 , wherein the first exhaust pipe is further provided with an on-pipe noise-regulating valve.