Manifold arrangement for exhaust systems

Abstract

A manifold arrangement for exhaust systems of internal combustion engines, especially multi-cylinder motorcycle engines, for installation between the exhaust gas outlet pipes from the or each cylinder and at least one muffler is configured such that the exhaust gas outlet pipes of the cylinders are combined stepwise, if applicable, so as to finally form one joint pipe where behind the joint pipe a branch is provided that divides the exhaust gas flow into at least two pipes which are separated from each other, are parallel in a flow-wise manner and together having a larger cross-sectional surface than the joint pipe and behind the pipes, parallel a joining element is provided again so as to form one single collector pipe. In order to achieve an increase in the efficiency over the full speed range, while eliminating adverse resonance phenomena and providing adequate sound damping, while at the same time having the smallest possible size, the arrangement is characterized in that the collector pipe has a free flow cross-section that matches at least the surface sum of the parallel pipes and that in the continuing collector pipe a component serving as a wave impedance is installed, which component allows the exhaust gas volume flow to pass unhindered while pressure waves are forced to perform a total reflection on the component, which total reflection is as complete as possible.

1 . A manifold arrangement for exhaust gas flow in exhaust systems of internal combustion engines, for installation between a single exhaust gas outlet pipe from each of one or more cylinders at an upstream position which, if from more than one cylinder, said single gas outlet pipes are joined into a single joint pipe, and at least one muffler at a downstream position, where downstream of said one single or said joint pipe a branch is provided that divides the exhaust gas flow into at least two pipes, said at least two pipes being separated from each other, being parallel in a flow-wise manner and together have a larger cross-sectional surface than the one single or joint pipe, and downstream of said parallel pipes a joining element is provided so as to form one single collector pipe, wherein said collector pipe has a free flow cross-section that matches at least a surface sum of said parallel pipes and that in said collector pipe a component serving as a wave impedance is installed, said component allowing the exhaust gas flow to pass unhindered while pressure waves are caused to perform a total reflection on said component.  
     
     
         2 . A manifold arrangement according to  claim 1 , wherein said total cross-sectional surface of said parallel pipes is at least 25% larger than said free flow cross-section of said joint pipe.  
     
     
         3 . A manifold arrangement according to  claim 2 , wherein said total cross-sectional surface of said parallel pipes is between 40% and 60% larger than said free flow cross-section of said joint pipe.  
     
     
         4 . A manifold arrangement according to  claim 1 , wherein a length of said parallel pipes is equal to at least twice a respective diameter of said parallel pipes.  
     
     
         5 . A manifold arrangement according to  claim 4 , wherein said joint pipe is configured as a joining element between the preceding outlet pipes and has a length that is at least equal to a diameter of said joint pipe.  
     
     
         6 . An manifold arrangement according to  claim 1 , wherein said parallel pipes are configured as parallel running pipe sections having substantially parallel axes.  
     
     
         7 . A manifold arrangement according to  claim 1 , wherein more than two parallel pipes are provided.  
     
     
         8 . A manifold arrangement according to  claim 1 , wherein said wave impedance is configured as a metal sheet provided with holes or slots.  
     
     
         9 . A manifold arrangement according to  claim 8 , wherein said wave impedance is configured as a substantially axis-parallel oriented perforated sheet cylinder whose side facing said parallel pipes is sealed, while an opposite side facing downstream components of said exhaust system, including said muffler, is open.  
     
     
         10 . A manifold arrangement according to  claim 8 , wherein said holes or slots have a non-negligible longitudinal dimension or are axially extended by means of short pipe sections or protuberances on the metal sheet.  
     
     
         11 . A manifold arrangement according to  claim 1 , wherein said wave impedance is a catalytic converter body with honeycombed pits.  
     
     
         12 . A manifold arrangement according to  claim 1 , wherein said wave impedance is a porous metal or ceramic body, comprised of sintered material.  
     
     
         13 . A manifold arrangement according to  claim 1 , wherein said wave impedance is a knit or woven device of metal filaments.  
     
     
         14 . A manifold arrangement according to  claim 8 , wherein a total cross-section of said through-openings in the wave impedance is larger than a total cross-section of said parallel pipes.  
     
     
         15 . A manifold arrangement according to  claim 14 , wherein said total cross-section of said through-openings is between approximately 30% and 40% larger than said total cross-section of said parallel pipes.  
     
     
         16 . A manifold arrangement according to  claim 1 , wherein said wave impedance is disposed directly downstream of said joining element where a distance to its end is at a maximum approximately twice a local pipe diameter.  
     
     
         17 . A manifold arrangement according to  claim 1 , wherein at least two branches and at least two joining elements are provided parallel relative to each other, where pipes of each branch lead to different joining elements.  
     
     
         18 . A manifold arrangement according to  claim 17 , wherein at least a first pipe and a second pipe lead up to said at least tow branches and at least one connecting element is provided between said first pipe and said second pipe.  
     
     
         19 . A manifold arrangement according to  claim 1 , wherein said internal combustion engine comprises a multi-cylinder motorcycle engine.  
     
     
         20 . A manifold arrangement for exhaust gas flow in an exhaust system of an internal combustion engine having at least one cylinder, wherein exhaust gases flow downstream from said at least one cylinder into one single exhaust outlet pipe and flow subsequently downstream into at least one muffler, said manifold arrangement being positioned between said outlet pipe and said muffler and comprising: 
 a branch connected downstream of said single exhaust outlet pipe that divides the exhaust gas flow into at least two pipes, 
 said at least two pipes being separated from each other, being parallel in a flow-wise manner and together having a larger cross-sectional surface than said single outlet pipe,  
   a joining element connected downstream of said parallel pipes to form one single collector pipe, 
 said collector pipe having a free flow cross-section that matches at least a surface sum of said parallel pipes,  
   a component serving as a wave impedance installed in said collector pipe, 
 said component arranged to allow the exhaust gas flow to pass unhindered while pressure waves are caused to perform a total reflection on said component.