Heat exchanger of an internal combustion engine

Abstract

A heat exchanger ( 18 ) is provided for an internal combustion engine ( 1 ) for heat transfer between a gas stream ( 8 ) and a working medium stream ( 10 ). The heat exchanger ( 18 ) comprises a housing ( 28 ), which encloses a gas path ( 38 ), and with at least one spiral tube ( 29 ), which carries a working medium path ( 30 ) and which is arranged in the gas path ( 38 ) and which extends helically in relation to the central longitudinal axis ( 31 ) of the housing ( 28 ). Increased fatigue strength is achieved with an elastic outer mounting layer ( 32 ). The elastic outer mounting layer ( 32 ) is arranged between the housing ( 28 ) and the at least one spiral tube ( 29 ).

What is claimed is: 
     
         1 . A heat exchanger for an internal combustion engine for transferring heat between a gas stream and a working medium stream, the heat exchanger comprising:
 a housing enclosing a gas path;   a spiral tube carrying the working medium and defining at least a part of a working medium path, the spiral tube being arranged in the gas path and extending helically in relation to a central longitudinal axis of the housing; and   an elastic outer mounting layer arranged between the housing and the spiral tube.   
     
     
         2 . A heat exchanger in accordance with  claim 1 , further comprising a core tube extending coaxially with the central longitudinal axis of the housing and arranged in the housing, wherein:
 the gas path is formed radially between the housing and the core tube;   the spiral tube is arranged between the housing and the core tube; and   the core tube encloses a bypass path, which bypass path bypasses the gas path in the area of the at least one spiral tube.   
     
     
         3 . A heat exchanger in accordance with  claim 2 , wherein the bypass path is fluidically connected with the gas path upstream of and downstream of the at least one spiral tube. 
     
     
         4 . A heat exchanger in accordance with  claim 2 , further comprising an elastic inner mounting layer, which is arranged between the core tube and the spiral tube. 
     
     
         5 . A heat exchanger in accordance with  claim 3 , wherein the core tube contains a control means for controlling a cross section of the bypass path, the flow passing through the cross section of the bypass path. 
     
     
         6 . A heat exchanger in accordance with  claim 5 , wherein the core tube projects over the housing at both longitudinal ends of the housing and forms a gas inlet and a gas outlet of the housing. 
     
     
         7 . A heat exchanger in accordance with  claim 6 , wherein the core tube is assembled axially from three tube sections, wherein an inlet section has the gas inlet, an outlet section has the gas outlet, and a control section has the control means. 
     
     
         8 . A heat exchanger in accordance with  claim 1 , wherein the at least one spiral tube has a plurality of ribs protruding into the gas path. 
     
     
         9 . A heat exchanger in accordance with  claim 1 , wherein the elastic mounting layer is at least one of: a ceramic fiber mat; a wire mesh; a metal wire mesh; a metal foam; a ceramic foam structure; a temperature-resistant material; a composite structure; and a swelling mat. 
     
     
         10 . A heat exchanger in accordance with  claim 4 , wherein the elastic inner mounting layer is at least one of: a ceramic fiber mat; a wire mesh; a metal wire mesh; a metal foam; a ceramic foam structure; a temperature-resistant material; a composite structure; and a swelling mat. 
     
     
         11 . A heat exchanger in accordance with  claim 1 , wherein the elastic mounting layer has a supporting mount at least on a side exposed to the gas stream. 
     
     
         12 . A heat exchanger in accordance with  claim 11 , wherein the supporting mount is at least one of: a wire mesh; a metal foil; a graphite foil; a graphite layer; a heat-resistant woven structure; a heat-resistant textile; a metal mesh; a wire mesh; and a metal foam. 
     
     
         13 . A heat exchanger in accordance with  claim 10 , wherein the elastic mounting layer has a fiber material, wherein the supporting mount is impervious to the fibers of the fiber material. 
     
     
         14 . A heat exchanger in accordance with  claim 1 , wherein the elastic mounting layer comprises a mounting mat extending as a closed mat in the circumferential direction. 
     
     
         15 . A heat exchanger in accordance with  claim 1 , wherein the elastic mounting layer is in contact with the adjacent housing and the spiral tube, respectively radially on the outside and radially on the inside. 
     
     
         16 . A heat exchanger in accordance with  claim 1 , wherein the elastic mounting layer is pressed radially. 
     
     
         17 . A heat exchanger system comprising:
 an internal combustion engine with an exhaust system with an exhaust gas stream;   a heat exchanger for transferring heat between the exhaust gas stream and a working medium stream, the heat exchanger comprising:   a housing enclosing a gas path;   a spiral tube carrying the working medium and defining at least a part of a working medium path, the spiral tube being arranged in the gas path and extending helically in relation to a central longitudinal axis of the housing; and   an elastic outer mounting layer arranged between the housing and the spiral tube.   
     
     
         18 . A heat exchanger system in accordance with  claim 17 , further comprising a core tube extending coaxially with the central longitudinal axis of the housing and arranged in the housing, wherein:
 the gas path is formed radially between the housing and the core tube;   the spiral tube is arranged between the housing and the core tube; and   the core tube encloses a bypass path, which bypass path bypasses the gas path in the area of the at least one spiral tube, wherein the bypass path is fluidically connected with the gas path upstream of and downstream of the at least one spiral tube.   
     
     
         19 . A heat exchanger system in accordance with  claim 18 , wherein the core tube contains a control means for controlling a cross section of the bypass path, the flow passing through the cross section of the bypass path. 
     
     
         20 . A heat exchanger system in accordance with  claim 18 , further comprising an elastic inner mounting layer, which is arranged between the core tube and the spiral tube.