Air-gap insulated exhaust manifold

Abstract

An air gap insulated exhaust manifold includes several inlet tubes which are fit into one another so as to be movable relative to each other and complement each other so as to constitute a collecting chamber. The inlet tubes are surrounded by an outlet tube, an air gap resulting between the inlet and outlet tubes. Two shell-type intermediate plates are provided in this air gap and complement each other so as to constitute a hollow body, which prevents that any leakage flows directly hit the outlet tube. The intermediate plates are produced by deep-drawing a pimpled foil.

1 .- 16 . (canceled) 
   
   
       17 . An air gap insulated exhaust manifold, comprising:
 at least one cylinder-side inlet tube,   at least one exhaust pipe side outlet tube spaced apart from the at least one cylinder-side inlet tube in the region of a collecting chamber to form an air gap which surrounds the collecting chamber at least in part, and   at least one intermediate plate arranged in the air gap.   
   
   
       18 . The exhaust manifold according to  claim 17 , wherein the at least one intermediate plate comprises a plurality of intermediate plates. 
   
   
       19 . The exhaust manifold according to  claim 18 , wherein the intermediate plates are fit into one another at their contact edges. 
   
   
       20 . The exhaust manifold according to  claim 17 , wherein the at least one intermediate plate is/are shell-shaped. 
   
   
       21 . The exhaust manifold according to  claim 17 , wherein the at least one intermediate plate form(s) a hollow body. 
   
   
       22 . The exhaust manifold according to  claim 17 , wherein the at least one intermediate plate has a maximum thickness of 0.3 mm. 
   
   
       23 . The exhaust manifold according to  claim 17 , wherein the at least one intermediate plate has a maximum thickness of 0.15 mm. 
   
   
       24 . The exhaust manifold according to  claim 17 , wherein the at least one intermediate plate covers at least 80% of the exposed inner side of the outer wall delimiting the air gap. 
   
   
       25 . The exhaust manifold according to  claim 17 , wherein the at least one intermediate plate subdivides the air gap into an inner and an outer portion. 
   
   
       26 . The exhaust manifold according to  claim 17 , wherein the at least one intermediate plate has protrusions which contact at least one of the inlet and outlet tubes. 
   
   
       27 . The exhaust manifold according to  claim 17 , wherein the at least one intermediate plate surrounds the inner one of the two tubes in the region of the collecting chamber. 
   
   
       28 . The exhaust manifold according to  claim 17 , wherein the at least one intermediate plate is a deep-drawn foil which prior to deep-drawing has a pimpled surface. 
   
   
       29 . The exhaust manifold according to  claim 17 , wherein the at least one intermediate plate has a shape corresponding to the external wall which delimits the air gap. 
   
   
       30 . The exhaust manifold according to  claim 17 , wherein the at least one intermediate plate is inserted in the air gap without being fastened to the inlet or outlet tubes. 
   
   
       31 . The exhaust manifold according to  claim 17 , wherein the at least one cylinder-side inlet tube comprises a plurality of cylinder-side inlet tubes which open into the outlet tube and are fit into one another so as to be movable relative to each other. 
   
   
       32 . The exhaust manifold according to  claim 31 , wherein the at least one intermediate plate surrounds all of the plurality of inlet tubes in the region of the collecting chamber. 
   
   
       33 . The exhaust manifold according to  claim 17 , wherein the at least one inlet tube(s) and the at least one outlet tube(s) are connected with each other at one end only, and that the inner one of the two tubes freely projects in an unsupported manner into the interior of the outer one of the two tubes.