Heat Exchanger Utilized As An EGR Cooler In A Gas Recirculation System

Abstract

A heat exchanger for exchanging heat between a first medium and a second medium has a body comprising a pair of header plates, a pair of distribution plates, and a pair of case body lateral panels. Input and output header plates have a plurality of orifices, with a flow path assembly extending between each input header plate orifice and the corresponding output header plate orifice. Each flow path assembly includes at least one chamber assembly, having a corresponding medium directing component, disposed between a pair of tubular segments. Input and output distribution plates have a plurality of orifices. A first medium inlet side tank engages with the input header, a first medium output side tank engages with the output header plate, a second medium inlet side tank engages with the input distribution plate, and a second medium output side tank engages with the output distribution plate.

Claims

1. A heat exchanger for exchanging heat between a first heat exchange medium and a second heat exchange medium, the heat exchange comprising: a parrallelpiped body having a first pair of parallel faces realized by an input header plate and an output header plate, a second pair of parallel faces realized by an input distribution plate and an output distribution plate, and a third pair of parallel faces realized by a first case body lateral panel and a second case body lateral panel, each of the input and output header plates having a plurality of orifices, each input header plate orifice having a corresponding output header plate orifice, and each of the input and output distribution plates having a plurality of orifices; a flow path assembly extending between each input header plate orifice and the corresponding output header plate orifice, each flow path assembly including at least one chamber assembly and a corresponding medium directing component disposed between a pair of tubular segments, each chamber assembly having first and second generally planar walls to at least partially define a chamber interior, the first chamber wall having an inlet orifice to provide fluid communication between a first tubular segment and the chamber interior, and the second chamber wall having an output orifice to provide fluid communication between a second tubular segment and the chamber interior, and the medium directing component being disposed within a corresponding chamber assembly and having a first side which has an angled surface facing the inlet orifice and the chamber interior, and having a second side which has an angled surface facing the output orifice and the chamber interior; a first medium inlet side tank engaged with the input header plate to provide fluid communication between a first medium inlet and each input header plate orifice; a first medium output side tank engaged with the output header plate to provide fluid communication between each output header plate orifice and a first medium output; a second medium inlet side tank engaged with the input distribution plate to provide fluid communication between a second medium inlet and each input distribution plate orifice; and a second medium output side tank engaged with the output distribution plate to provide fluid communication between each output distribution plate orifice and a second medium output.

2. The heat exchanger of claim 1, wherein for a chamber assembly disposed between first and second tubular segments, the chamber assembly flow path surface area is equal to or greater than the flow path surface area of each of the respective first and second tubular segments.

3. The heat exchanger of claim 1, wherein a chamber assembly in a flow path assembly has an outside diameter which is in the range of 1.5 to 2.5 times the outside diameter of the tubular segments within the same flow path assembly.

4. The heat exchanger of claim 3, wherein the outside diameter of the chamber assembly is substantially equal to twice the outside diameter of the tubular segments.

5. The heat exchanger of claim 3, wherein a portion of a chamber assembly in a first flow path assembly is positioned adjacent to a tubular segment of a second flow path assembly, interposed between a portion of a first chamber assembly and a portion of a second chamber assembly of the second flow path assembly.

6. The heat exchanger of claim 1, wherein each of the input header plate orifices is axially aligned with the corresponding output header plate orifice.

7. The heat exchanger of claim 1, wherein each of the input distribution plate orifices has a corresponding output distribution plate orifice.

8. The heat exchanger of claim 7, wherein each of the input distribution plate orifices is axially aligned with the corresponding output distribution plate orifice.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] FIG. 1 is a side view of a heat exchanger according to an embodiment of the present invention;

[0027] FIG. 2 is a top view of the heat exchanger according to an embodiment of the present invention;

[0028] FIG. 3 is a cross-sectional view of the heat exchanger taken along the line 1-1 of FIG. 2;

[0029] FIG. 4 is a cross-sectional view of the heat exchanger taken along the line 2-2 of FIG. 2;

[0030] FIG. 5A is a side view of a core assembly according to an embodiment of the present invention;

[0031] FIG. 5B is a schematic side view of a core assembly according to an embodiment of the present invention;

[0032] FIG. 5C is a schematic front view of a core assembly according to an embodiment of the present invention;

[0033] FIG. 6A is a schematic front view of flow path assemblies within the vessel according to an embodiment of the present invention;

[0034] FIG. 6B is a schematic side view of a flow path assembly according to an embodiment of the present invention;

[0035] FIG. 6C is a schematic front view of a chamber assembly according to an embodiment of the present invention;

[0036] FIG. 6D is a schematic cross-sectional side view of a chamber assembly;

[0037] FIG. 7 is an exploded perspective view of a heat exchanger according to an embodiment of the present invention; and

[0038] FIGS. 8A-8G are top views of distribution plates according to various embodiments of the present invention.

DETAILED DESCRIPTION

[0039] Referring to the drawings and in particular FIG. 1 and FIG. 2, an embodiment of a heat exchanger 100 is shown. In an EGR cooler application, heat exchange medium being cooled is typically exhaust gas from an internal combustion engine. The cooling medium is typically engine coolant diverted from a cooling loop of an internal combustion engine. The heat exchanger 100 includes a cooling medium inlet side tank 165, a cooling medium outlet side tank 180, an exhaust gas inlet side tank 140 and an exhaust gas outlet side tank 155.

[0040] The heat exchanger 100 is provided with an exhaust gas inlet pipe 115 to facilitate flow of exhaust gas into the heat exchanger 100 via the exhaust gas inlet side tank 140. The exhaust gas inlet pipe 115 is hollow, permitting flow of exhaust gas therethrough. A first flange 120 is coupled to the gas inlet pipe 115 to facilitate attachment of the heat exchange 100 to an exhaust gas source. The first flange 120 is generally planar, provided with a generally flat surface to facilitate secure sealing. The first flange 120 may also be provided with a securing mechanism to couple the first flange 120 to the exhaust gas source, by utilizing nuts and bolts, for example. To permit use of nuts and bolts for attachment purposes, the first flange 120 may be provided with a plurality of bolt holes 305 (see FIGS. 3 and 7). The exhaust gas inlet pipe 115 may be coupled to the exhaust gas inlet tank 140 by brazing, soldering, or welding. The exhaust gas inlet pipe 115 may also be coupled to the exhaust gas inlet tank by mechanical means, such as flaring, for example. The exhaust gas inlet pipe 115 may also be coupled to the first flange 120 by brazing, soldering, or welding, or by mechanical means, such as flaring, for example. A combination of two or more coupling methods may also be used.

[0041] The heat exchanger 100 is also provided with an exhaust gas outlet pipe 125 to facilitate discharge of cooled exhaust gas out of the heat exchanger 100 via the exhaust gas outlet side tank 155. The exhaust gas output pipe 125 is hollow, permitting flow of exhaust gas therethrough. The exhaust gas output 125 may be provided with a second flange 122 to facilitate attachment of the heat exchanger 100 to an exhaust gas discharge output. The second flange 122 is generally planar, provided with a generally flat surface to facilitate secure sealing. The second flange 122 may also be provided with a securing mechanism to couple the second flange 122 to the exhaust gas discharge output, by utilizing nuts and bolts, for example. To permit use of nuts and bolts for attachment purposes, the second flange 122 may be provided with a plurality of bolt holes 305 (see FIGS. 3 and 7). The exhaust gas outlet pipe 125 may be coupled to the exhaust gas outlet side tank 155 by brazing, soldering, or welding. The exhaust gas outlet pipe 125 may also be coupled to the exhaust gas outlet side tank by mechanical means, such as flaring, for example. The exhaust gas outlet pipe 125 may also be coupled to the second flange 122 by brazing, soldering, or welding, or by mechanical means, such as flaring, for example. A combination of two or more coupling methods may also be used.

[0042] In a preferred embodiment of the present invention, one exhaust gas inlet pipe 115 and one exhaust gas outlet pipe 125 are provided. In other embodiments of the present invention, a plurality of exhaust gas inlet pipes 115 may be provided. In yet another embodiment of the present invention, a plurality of exhaust gas outlet pipes 125 may be provided.

[0043] Referring again to FIG. 1, the heat exchanger 100 is provided with a cooling medium inlet pipe 105 to permit flow of cooling medium into the heat exchanger 100 via the cooling medium inlet side tank 165. The heat exchanger 100 is also provided with a cooling medium outlet pipe 110 to permit discharge of cooling medium out of the heat exchanger 100 via the cooling medium outlet side tank 180. In one embodiment of the present invention, one cooling medium inlet pipe 105 and one cooling medium outlet pipe 110 are provided. In other embodiments of the present invention, a plurality of cooling medium inlet pipes 105 may be provided. In yet another embodiment of the present invention, a plurality of cooling medium outlet pipes 110 may be provided. The cooling medium inlet pipe 105 and cooling medium outlet pipe 110 are hollow, permitting flow of cooling medium therethrough.

[0044] Referring to FIG. 7, an exploded perspective view of a heat exchanger 100 according to an embodiment of the present invention is shown. The heat exchanger body may be generally rectangular or square in shape and includes three pairs of planar faces. The first pair of planar faces comprises an input header plate 145 and an output header plate 150. The input header plate 145 and the output plate header plate 150 are generally rectangular or square in shape. The input header plate 145 has a plurality of orifices 147, and the output header plate 150 has the same number of orifices 152 (not visible in FIG. 7). Each input header orifice 147 is preferably axially aligned with a corresponding output header orifice 152, and a flow path assembly 130 extends between each axially aligned pair of input header orifices and output header orifices.

[0045] The second pair of planar faces forming the heat exchanger body consists of an input distribution plate 170 and an output distribution plate 175. The input distribution plate 170 and the output distribution plate 175 are generally rectangular or square in shape. The front edge of the input distribution plate 170 is coupled to one edge of the input header plate 145. The front edge of the output distribution plate 175 is coupled to the opposite edge of the input header plate 145. The back edge of the input distribution plate 170 is coupled to one edge of the output header plate 150. The back edge of the output distribution plate 175 is coupled to the opposite edge of the output header plate 150. The input distribution plate 170 has a plurality of orifices 172 (not visible in FIG. 7). The outlet distribution plate 175 has a plurality of orifices 177. In a preferred embodiment, the input distribution plate 170 and the outlet distribution plate 175 have the same number of orifices, and in the most preferred embodiment, an input distribution plate orifice 172 is axially aligned with an output distribution plate orifice 177.

[0046] The two remaining planes of the heat exchanger body comprise a first case body lateral panel 280 and a second case body lateral panel 282. The front edge of the first case body lateral panel 280 is coupled to a first side edge of the input header plate 145, and the back edge of the first case body lateral panel 280 is coupled to a first side edge of the output header plate 150. The first case body lateral panel 280 is also coupled to a first side edge of the input distribution plate 170 and a first side edge of the output distribution plate 175. The second case body lateral panel 282 is coupled to a second side edge of the input header plate 145 and a second side edge of the output header plate 150. The second case body lateral panel 282 is also coupled to a second side edge of the input distribution plate 170 and a second side edge of the output distribution plate 175. The input header plate 145, the output header plate 150, the input distribution plate 170, the output distribution plate 175, the first case body lateral panel 280, and the second case body lateral panel 282 are coupled together to form the heat exchanger case body 300.

[0047] On the outwardly facing surface of the input header plate 145, the exhaust gas inlet side tank 140 is sealingly coupled. The exhaust gas inlet side tank body 140 is provided with the exhaust gas inlet pipe 115 to introduce exhaust gas into the heat exchanger 100. On the outwardly facing surface of the output header plate 150, the exhaust gas outlet side tank 155 is sealingly coupled. The exhaust gas outlet side tank 155 is provided with the exhaust gas outlet pipe, to discharge exhaust gas out of the heat exchanger 100. On the outwardly facing surface of the distribution plate 170, the cooling medium inlet side tank 165 is sealingly coupled. The cooling medium inlet side tank 165 is provided with the cooling medium inlet pipe 105 to introduce cooling medium into the heat exchanger 100. On the outwardly facing surface of the output distribution plate 175, the cooling medium outlet side tank 180 is sealingly coupled. The cooling medium outlet side tank 180 is provided with the cooling medium outlet pipe 110 to discharge cooling medium out of the heat exchanger 100.

[0048] Reference is now made to FIGS. 3 and 4, FIG. 3 being a cross-sectional view taken along the line 1-1 of FIG. 2, and FIG. 4 being a cross-sectional view taken along the line 2-2 of FIG. 2. Exhaust gas travelling through the exhaust gas inlet pipe 115 is introduced into the exhaust gas inlet side tank 140. The exhaust gas inlet side tank 140 is in fluid communication with the input header plate 145. The input header plate 145 is provided with the plurality of input header plate orifices 147. A first end of a flow path assembly 130 is matingly coupled to each of the input header plate orifices 147 provided in the input header plate 145. A flow path assembly 130 may by brazed, soldered, welded, or mechanically coupled to the input header plate 145. Preferably there are a plurality of input header plate orifices 147 on the input header plate 145 and a like plurality of flow path assemblies 130. Exhaust gas introduced into the exhaust gas inlet side tank 140 flows through an input header plate orifice 147 into one or a plurality of flow path assemblies 130. A second end of a flow path assembly 130 is matingly coupled to the output header plate 150. The output header plate 150 is provided with a plurality of output header plate orifices 152, each of which is in fluid communication with the second end of a flow path assembly 130. The flow path assembly 130 may be brazed, soldered, welded, or mechanically coupled to the output header plate 150. Exhaust gas that has completed flow through the plurality of flow path assemblies 130 flows through the output header plate orifices 152 and is discharged into the exhaust gas outlet side tank 155. Once the exhaust gas is collected in the exhaust gas outlet side tank 155, the exhaust gas is discharged out of the heat exchanger 100 via the exhaust gas outlet pipe 125 coupled to the exhaust gas outlet side tank 155.

[0049] Cooling medium traveling through the cooling medium inlet 105 is introduced into the cooling medium inlet side tank 165 and then into the heat exchanger body 300, via the orifices 172 in the input distribution plate 170. The coolant travels through the heat exchanger, around the exterior surfaces of the flow path assemblies 130 and then through the orifices 177 in the output distribution plate 175. The coolant then collects in the cooling medium outlet side tank 180 and is discharged out of the heat exchanger via the cooling medium outlet 110.

[0050] With reference to FIG. 3, the exhaust gas (left to right) flow path 135 is through the exhaust gas inlet 115, the gas inlet side tank 140, the orifices 147 within the input header plate 145, the interior of the respective flow path assemblies 130, the orifices 152 in the output header plate 150, the gas outlet side tank 155 and the exhaust gas outlet 125. With reference to FIGS. 3 and 4, the coolant (top to bottom) flow path is through the cooling medium inlet 105, the cooling medium inlet side tank 165, the orifices 172 in the input distribution plate 170, around the exterior surfaces of the respective flow path assemblies 130, the orifices 177 in the output distribution plate 175, the cooling medium outlet side tank 180 and the cooling medium outlet 110.

[0051] A water tight vessel 160 for the cooling medium is provided by the cooling medium inlet side tank 105, the non-orifice portions of the input and output header plates 145, 150, the first and second case body lateral panels 280, 282, and the cooling medium outlet side tank 180. The flow path assemblies 130 are also within the vessel 160, with the exterior surfaces of the flow path assemblies coming into contact with the coolant. The heat contained within the exhaust gas flowing within the interior of the flow path assemblies 130 is transferred via the assemblies to the coolant and is removed as the coolant is circulated through the vessel 160 and the cooling system of the engine.

[0052] Referring to FIG. 5A, a flow path assembly 130 disposed between the input header plate 145 and the output header plate 150 comprises at least one chamber assembly 190 disposed between two tube sections 185. In combination, the tube sections 185 and chamber assemblies provide flows paths 135 for the exhaust gas. As shown in FIG. 5A (see also FIG. 6B), each chamber assembly 190 has a pair of planar walls 195, 205, and a lateral 200 which connects the first and second planar walls.

[0053] Referring now to FIG. 5B and FIG. 5C, a first flow path assembly 130A and a second flow path assembly 130B are arranged so that a chamber section 190C of the second flow path assembly 130B is located substantially adjacent to a tubular section 185B of the first flow path assembly 130A, interposed between a first chamber section 190A and a second chamber section 190B of the first flow path assembly 130A. Similarly, a first tubular section 185C of the second flow path assembly 130B is arranged substantially adjacent to the first chamber section 190A of the first flow path assembly 130A. Furthermore, the position of the second flow path assembly 130B is arranged in relation to the first flow path assembly 130A, such that the outer circumference of the chamber section 190A and of the chamber section 190B of the first flow path assembly 130A overlap the outer circumference of the chamber section 190C and of the chamber section 190D of the second flow path assembly 130B. In an embodiment of the present invention, the first flow path assembly 130A and the second flow path assembly 130B are positioned, such that the first flow path assembly 130A and second flow path assembly 130B are spaced apart, allowing flow of heat exchange medium between the first flow path assembly 130A and the second flow path assembly 130B. In another embodiment of the present invention, the first flow path assembly 130A and the second flow path assembly 130B are positioned, such that the first flow path assembly 130A and second flow path assembly 130B are in contact with one another.

[0054] To efficiently package a plurality of flow path assemblies 130 within the vessel 160, the ratio of the outside diameter of the tube sections 185 to the outside diameter of the chamber assemblies 190 is selected to be within the range of 1:1.5 to 1:2.5. In a preferred embodiment of the invention, such ratio is selected to be 1:2 within the tolerance of manufacture. Thus, in the preferred embodiment, if the tube section 185 outside diameter is 5 mm, the chamber assembly 190 has an outside diameter of 10 mm. Similarly, if the tube section 185 outside diameter is 6 mm, the chamber assembly 190 has an outside diameter of 12 mm. In the most preferred embodiment of the invention, the 1:2 outside diameters ratio is utilized and the flow path assemblies 130 are arranged as shown in, and described with respect to, FIGS. 5A and 5B without the flow path assemblies 130 being in physical contact with each other. As the plurality of flow path assemblies 130 are staggeringly arranged within the vessel 160, the cooling medium is obstructed from flowing in a generally straight line within the vessel. The cooling medium that first comes into contact with the exterior of the lateral wall 200 of the chamber assembly 190 of a flow path assembly 130 is directed laterally along the external contour of the lateral wall 200 of the chamber assembly 190. As the plurality of flow path assembly 130 are staggeringly arranged within the vessel 160, the cooling medium directed laterally along the exterior contour of the plurality of lateral walls 200 of the chamber assemblies 190 then generally comes into contact with the tubular sections 185 of the adjacent flow path assembly 130. The process is repeated until the cooling medium reaches the output distribution plate 175. The output distribution plate 175 is positioned on the opposite plane from the input distribution plate 170 of the vessel 160. The output distribution plate 175 is provided with the plurality of output distribution plate orifices 177, permitting flow of the cooling medium from the vessel 160 to the outlet side cooling medium tank 180. The staggered arrangement of the tube sections 185 and the chamber sections 190 provides multiple interruptions to the flow of the cooling heat exchange medium flowing around the plurality of flow path assemblies 130, thereby enhancing the heat transfer effectiveness of the cooling heat exchange medium.

[0055] Referring now to FIGS. 6B and 6C schematic side and frontal views of a flow path assembly 130 are respectively shown. The flow path assembly 130 comprises the plurality of tube sections 185 and at least one chamber section 190. The chamber section 190 has the first planar wall 195, the second planar wall 205, and the lateral wall 200 concentrically connecting the outer circumference of the first planar wall 195 and the second planar wall 205. The first planar wall 195 and the second planar wall 205 are set apart at a predetermined distance to allow a gap between each other. The lateral wall 200 connects the outer circumference of the first planar wall and the second planar wall to form a watertight seal. The chamber section 190 is hollow, allowing flow of exhaust gas within. The flow path assembly 130 provides the flow path 135 to permit flow of the exhaust gas within.

[0056] Disposed within the chamber section 190 is a medium directing component 220. The medium directing component 220 is at least partially coupled to the planar wall 195 of the chamber section 190, extends laterally through the chamber section 190, and is at least partially coupled to the planar wall 205 of the chamber section 190. The planar wall 195 of the chamber section 190 is provided with an inlet orifice 210, allowing flow of exhaust gas into the chamber section 190. Coupled to the inlet orifice 210 of the chamber section 190 is a tube section 185, piping exhaust gas into the chamber section 190 from the exhaust gas inlet side tank 140 via an orifice 147 in the input header plate 145. The planar wall 205 of the chamber section 190 is provided with an outlet orifice 215, allowing discharge of exhaust gas out of the chamber section 190. Coupled to the outlet orifice 215 is a tube section 185. Multiple sets of chamber sections 190 and tube sections 185 may be interconnected to provide a flow path assembly 130 that terminates at an orifice 152 in the output header plate 150. As previously explained, multiple sets of flow path assemblies 130 may be disposed between the input header plate 145 and the output header plate 150.

[0057] The exhaust gas introduced into flow path 135 within the flow path assembly 130 first flows in an initial line of flow within the tube section 185. The tube section 185 is coupled to the chamber section 190. The tube section 185 is hollow, permitting flow of exhaust gas within. The chamber section 190 is provided with the inlet orifice 210, permitting flow of exhaust gas into the chamber section 190 from the tube section 185. As exhaust gas enters the chamber section 190 through the inlet orifice 210, exhaust gas comes into contact with the first side 225 of the medium directing component 220. The first side 225 of the medium directing component 220 facing the inlet orifice 210 is set at an angle to direct exhaust gas to a second line of flow, wherein the second line of flow is generally perpendicular to the initial line of flow. As exhaust gas is directed into the second line of flow, exhaust gas is directed into the interior of the chamber assembly 190. As exhaust gas enters the chamber section 190, exhaust gas is led towards a first end 235 of the chamber assembly 190 (see FIG. 6C). Once exhaust gas reaches the first end 235 of the chamber assembly 190, the flow of exhaust gas is diverted into two divergent flows, generally symmetrical to one another, in a semi-circular manner within the chamber assembly 190. In another embodiment of the present invention, as the exhaust gas reaches the first end 235 of the chamber assembly 190, the flow of exhaust gas is diverted into two divergent semi-circular flow paths within the chamber assembly 190, yet the two divergent flow paths are not symmetrical to one another. In the preferred embodiment of the present invention, the diameter of the chamber section 190 is substantially larger than the diameter of the tube section 185.

[0058] The two semi-circular flow patterns flow away from each other, while generally axially aligned to one another, following the contour of the interior of the chamber assembly 190. The first semi-circular flow follows the contour of the first lateral contour 240 of the interior chamber of the chamber assembly 190. The second semi-circular flow follows the contour of the second lateral contour 245 of the chamber assembly 190. After exhaust gas completes the semi-circular flow within the chamber assembly 190, flowing along the interior contour of the chamber assembly 190, the two semi-circular flows converge to form one single flow once again generally around a second end 250 of the chamber section of the chamber assembly 190. The second end 250 of the chamber section at which the two semi-circular flow paths converge is generally on the end opposite to the first end 235 of the chamber section.

[0059] As the two semi-circular exhaust gas flows converge into one main flow again at the second end 250 of the chamber assembly 190, exhaust gas is simultaneously directed in a new flow path, wherein the angle of an attack of the new flow path is substantially divergent from the lines of flow of the respective semi-circular flow paths. As the two semi-circular flows within the chamber assembly 190 converge at the second end 250 of the chamber assembly, the converged flow of exhaust gas is directed towards a second surface 230 of the medium directing component 220 (see FIG. 6B). The second surface 230 of the medium directing component 220 is set at an angle, generally diverting the flow of exhaust gas to nearly a perpendicular flow direction, axially aligned to the axis of a second tubular section 185. The second surface 230 of the medium directing component 220 is generally on the side opposite of the first surface 225 of the medium directing component 220. The second tubular section 185 is connected to the second planar wall 205 of the chamber assembly 190. The second planar wall 205 of the chamber assembly 190 is provided with an outlet orifice 215 to permit flow of exhaust gas from the interior of the chamber assembly 190 into the second tubular section 185. In another embodiment of the present invention, the two semi-circular flow patterns flow away from each other, following the contour of the interior of the chamber assembly 190, yet may not be axially aligned to one another.

[0060] The flow path assembly 130 may comprise of a plurality of tube section 185, chamber section 190, and medium directing component 220 assemblies. As such, the flow pattern as described herein may be repeated several times dependent upon the number of tubular sections 185, chamber sections 190, and medium directing components 220 contained within a particular flow path assembly 130. As the exhaust gas travels within the interior of a chamber assembly 190, as well as directly through the tube sections 185, the flow path 135 is substantially longer than the axial length of the tube sections 185 and chamber assembly 190 components. The heat exchange surface area provided by a flow path assembly 130 is therefore substantially greater than that provided by prior art designs in which exhaust gas flows through only round or rectangular tubes.

[0061] Further, in combination, the tube sections 185 and chamber assemblies provide a number of obstructions within the flow path 135 which causes the exhaust gas flow to be forcefully and repeatedly disrupted from continuing to flow in an establish flow. Such obstructions include the first surface 225 of the medium directing component 220, the first end 235 of the chamber assembly 190, the second end 250 of the chamber assembly 190 and the second surface 230 of the medium directing component 220. Each of these disruptions provides a plurality of mixing action and turbulence inducing flow patterns to the exhaust gas. The mixing action and turbulence inducing flow patterns serve to counter the natural tendency of the exhaust gas to establish a boundary layer along the surface of the flow path. Disrupting the establishment of such a boundary layer not only enhances heat transfer effectiveness, it also counters the tendency of contaminants, such as carbon or soot, to settle on the surface of the flow path.

[0062] In FIG. 6A and FIG. 6B, the tubular section 185 is illustrated as being hollow and circular. In other embodiments, the tubular structure 185 may be hollow but non-circular, such as an oval, rectangular shape, or other geometric shapes. In the illustrated embodiment, the chamber section 190 is hollow and circular in shape. In other embodiments, the chamber section 190 may be hollow, but non-circular in shape, such as an oval or rectangular shape, for example. Additionally, when a plurality of chamber sections 190 are combined together in a flow path assembly 130, a first chamber section 190 may be circular, whereas a second chamber section 190 is non-circular. Also, when a plurality of tube sections 185 are combined together in a flow path assembly 130, a first tube section 185 may be circular, whereas a second tube section 185 is non-circular.

[0063] The tubular section 185, chamber section 190, and the medium directing component 220 may be made of stainless steel. The tubular section 185, chamber section 190, and the medium directing component 220 may also be made of other ferrous or non-ferrous material, or other suitable material. The tubular section 185, chamber section 190, and the medium directing component 220 may be coupled together with brazing paste or without brazing paste. In other embodiment of the present invention, the tubular section 185, chamber section 190, and the medium directing component 220 may be coupled together with brazing material. Also, an embodiment of the present invention allows for the tubular section 185, the chamber section 190, and the medium directing component 220 to be made of materials different from each other. Additionally, a sealing material may be used to seal between various components utilized to form the heat exchanger 100.

[0064] The size of a chamber section 190 may vary from one chamber section to the next. The medium directing component 220 facilitates exhaust gas agitating and turbulence inducing flow, maximizing exhaust gas enhancing heat transfer effectiveness. The inner surface of the chamber section 190 may feature indentations to increase the surface area. The medium directing component 220 may also feature indentations. The indentations featured on the interior or the exterior of the chamber sections 190 may also be put in place to alter the flow pattern or the flow speed of exhaust gas flowing in the chamber section 190 or of the cooling medium flowing outside of the chamber sections 190. The chamber sections 190 may have other surface features such as, but not limited to, louvers or dimples, as well as other extended surface features to alter the fluid flow characteristics within or outside the chamber sections 190.

[0065] As schematically shown in FIG. 6B, a tube section 185 may terminate at the inlet orifice 210 of a chamber assembly 190. Alternatively, portions of a single tube may extend through the inlet and orifices of one or more chamber assemblies with the chamber interior being positioned over inlet and outlet orifices located on opposite sides of the tube. Further, a chamber assembly may include, in addition to the main chamber schematically shown in FIG. 6B, first and second sub-chambers respectively associated with the planar walls 195,205 and having lateral walls which fittingly engage with, and are bonded to, lateral walls of the medium directing components, as described in U.S. Pat. No. 9,151,547, the disclosure of which is incorporated herein by reference.

[0066] Referring now to FIG. 6D, as exhaust gas flows through the flow path 135, pressure drop due to friction factor as well as pressure drop due to exhaust gas directional changes within the flow path assembly 130 cannot be avoided. However, pressure drop due to flow path surface area constriction can be minimized as long as the baseline flow path surface area established by the tube section 185 is maintained throughout the chamber assembly 190 flow path. Therefore, in the preferred embodiment of the present invention, the dimensions of the tube section and the chamber assembly components are selected such that: tube section flow path surface area (T.sub.FLOW SURFACE AREA)≦chamber assembly total flow path surface area (C.sub.FLOW SURFACE AREA).

[0067] The baseline tube section flow path surface area, T.sub.FLOW SURFACE AREA, for a tube having an inside diameter, T.sub.ID, is equal to π×(T.sub.ID/2).sup.2. T.sub.ID is determined by subtracting the tube wall thickness from the tube outside diameter T.sub.OD, thus T.sub.ID=T.sub.OD−2×(Tube.sub.Wall Thickness).

[0068] To determine the total chamber assembly flow path surface area, C.sub.FLOW SURFACE AREA, the following calculation method is utilized. As the chamber assembly flow path is generally rectangular in shape, the surface area of the chamber flow path is determined by calculating for rectangular surface area by multiplying the flow path width, F.sub.WIDTH, by the lateral wall inside height, Lateral Wall.sub.IH: C.sub.FLOW SURFACE AREA=F.sub.WIDTH×Lateral Wall.sub.IH.

[0069] To determine F.sub.WIDTH, the chamber inside diameter, C.sub.ID, is first determined by subtracting the two lateral material thicknesses, C.sub.LATERAL WALL THICKNESS 1 and C.sub.LATERAL WALL THICKNESS 2, from the chamber outside diameter C.sub.OD: C.sub.ID=C.sub.OD−C.sub.LATERAL WALL THICKNESS 1−C.sub.LATERAL WALL THICKNESS 2.

[0070] To complete the calculation of the flow path width, F.sub.WIDTH, within the chamber assembly 190, the tube inside diameter, T.sub.ID, is subtracted from C.sub.ID: F.sub.WIDTH=C.sub.ID−T.sub.ID.

[0071] To determine Lateral Wall.sub.IH, the top and the bottom chamber wall thickness, C.sub.TOP WALL THICKNESS and C.sub.BOTTOM WALL THICKNESS, are subtracted from the external lateral wall 200 height, Lateral Wall.sub.OH: Lateral Wall.sub.IH=Lateral Wall.sub.OH−C.sub.TOP WALL THICKNESS−C.sub.BOTTOM WALL THICKNESS.

[0072] For example, if the T.sub.OD is 6 mm and the Tube.sub.Wall Thickness is 0.3 mm, then the T.sub.ID would be 5.4 mm. The C.sub.FLOW SURFACE AREA would then be equal to π×(5.4/2).sup.2 or 22.89 mm.sup.2. Establishing the T.sub.OD to C.sub.OD relationship as 1:2, then the C.sub.OD would be 12 mm. Setting the C.sub.LATERAL WALL THICKNESS 1 and C.sub.LATERAL WALL THICKNESS 2 at 0.3 mm, then the C.sub.ID would be 11.4 mm. F.sub.WIDTH would therefore be 6 mm. If C.sub.TOP WALL THICKNESS and C.sub.BOTTOM WALL THICKNESS are both 0.3 mm, then as long as Lateral Wall.sub.OH is equal to or greater than 4.415 mm, then it meets the criteria, T.sub.FLOW SURFACE AREA≦C.sub.FLOW SURFACE AREA minimizing pressure drop due to the constriction of flow path surface area in the flow path assembly 130.

[0073] Referring to FIGS. 8A-8G, different embodiments of a distribution plate 170 are shown. Referring now to FIG. 8A, an embodiment of a distribution plate 170 is shown. The distribution plate 170A is generally planar, provided with a plurality of input distribution plate orifices 172. The input distribution plate orifices 172 extend from one side of the distribution plate 170A and extend to the opposing side of the distribution plate 170A, permitting flow of the cooling medium through the distribution plate 170A. The input distribution plate orifices 172 may be uniform in size, and arranged along the distribution plate 170A with equal spacing.

[0074] Now referring to FIG. 8B, another embodiment of a distribution plate 170 is shown. A distribution plate 170B is generally planar, provided with a plurality of input distribution plate orifices 172 and input distribution plate orifices 172A. Input distribution plate orifices 172 and input distribution plate orifices 172A extend from one side of the distribution plate 170B and extend to the opposing side of the distribution plate 170B, permitting flow of the cooling medium through the distribution plate 170B. The input distribution plate orifices 172 and the input distribution plate orifices 172A are of varying size and geometric shape. In an embodiment of the present invention, the larger input distribution plate orifices 172A may be placed over an area of the vessel 160 where it may be desired to distribute more cooling medium, as larger diameter input distribution plate orifices 172A may direct more cooling medium to the particular area of the vessel 160.

[0075] Now referring to FIG. 8C, an embodiment of a distribution plate 170 is shown. A distribution plate 170C is generally planar, provided with a plurality of input distribution plate orifices 172B. The input distribution plate orifices 172B extend from one side of the distribution plate 170C to the opposing side of the distribution plate 170C, permitting flow of the cooling medium through the distribution plate 170C. Input distribution plate orifices 172B may be uniform in size, and arranged along the distribution plate 170C with equal spacing. Input distribution plate orifices 172B may have an oval shape, instead of a round shape, to provide a desired cooling medium distribution pattern within the vessel 160.

[0076] Referring to FIG. 8D, another embodiment of a distribution plate 170 is shown. A distribution plate 170D is generally planar, provided with a plurality of input distribution plate orifices 172 and input distribution plate orifices 172C. Input distribution plate orifices 172 and input distribution plate orifices 172C extend from one side of the distribution plate 170D to the opposing side of the distribution plate 170D, permitting flow of the cooling medium through the distribution plate 170. Input distribution plate orifices 172 and input distribution plate orifices 172C are of varying size and shape. Input distribution plate orifices 172 are generally round. Input distribution plate orifices 172C are generally of an oval shape. In an embodiment of the present invention, the larger input distribution plate orifices 172C may be placed over area of the vessel 160 to direct more cooling medium to the particular area of the vessel 160. Input distribution plate orifices 172 may be uniform in size and arranged along the distribution plate 170D with equal spacing.

[0077] Now referring to FIG. 8E a distribution plate 170E is generally planar, provided with a plurality of input distribution plate orifices 172D. Input distribution plate orifices 172D extend from one side of the distribution plate 170 to the opposing side of the distribution plate 170E, permitting flow of the cooling medium through the distribution plate 170E. Input distribution plate orifices 172D may be uniform in size, and arranged along the distribution plate 170E with equal spacing.

[0078] Now referring to FIG. 8F a distribution plate 170F is generally planar, provided with a plurality of input distribution plate orifices 172E. Input distribution plate orifices 172E extend from one side of the distribution plate 170F to the opposing side of the distribution plate 170F, permitting flow of cooling medium through the distribution plate 170F. Input distribution plate orifices 172E may be uniform in size, and arranged along the distribution plate 170F with equal spacing. Input distribution plate orifices 172E may be populated from one end of the distribution plate 170F to the opposing end of the distribution plate 170F. Input distribution plate orifices 172E may be of rectangular shape or other geometric shapes, such as an oval, for example.

[0079] Referring now to FIG. 8G, another embodiment of a distribution plate 170 is shown. A distribution plate 170G is generally planar, provided with a plurality of input distribution plate orifices 172E. Input distribution plate orifices 172E extend from one side of the distribution plate 170G to the opposing side of the distribution plate 170G, and permit flow of the cooling medium through the distribution plate 170G. The input distribution plate orifices 172E may be uniform in size and arranged along the distribution plate 170G with equal spacing. The input distribution plate orifices 172E may be populated from one end of the distribution plate 170G to the opposing end of the distribution plate 170G. The input distribution plate orifices 172E may be of rectangular shapes or other geometric shapes, such as an oval, for example. The input distribution plate orifices 172E may be concentrated over a particular area of the vessel 160 to provide more cooling medium to that specific area of the vessel 160. The input distribution plate orifices 172E may also be sparsely populated over a specific section of the distribution plate 170G to restrict flow of the cooling medium over that particular section of the vessel 160.

[0080] The configuration and arrangement of a plurality of output distribution plate orifices 177 provided on the output distribution plate 175 may be identical to the configuration of the input distribution plate orifices 172 on the input distribution plate 170. In another embodiment of the present invention, the output distribution plate orifices 177 on the outlet distribution plate 175 may not mirror the configuration of the input distribution plate orifices 172 on the input distribution plate 170.

[0081] In yet another embodiment of the present invention, the input distribution plate 170 may not be utilized where cooling medium introduced into the cooling medium inlet side tank 165 is directly fed to the exterior surfaces of the flow path assemblies 130 contained within the heat exchanger 100. In yet another embodiment of the present invention, the input distribution plate 170 may be utilized while the outlet distribution plate 175 is not utilized. In such an embodiment, the cooling medium is directed straight to the cooling medium output side tank 180 once it completes its flow around the flow path assemblies 130 contained within the heat exchanger 100.

[0082] Many modifications and variations of the present invention are possible in light of the above teachings. Therefore, within the scope of the appended claims, the present invention may be practiced other than as specifically described. For example, the present invention described herein assumes application of the heat exchanger 100 as an EGR cooler. However, the heat exchanger may be utilized in other applications. Therefore, the heat exchange medium flowing inside the plurality of flow path assemblies 130 of the heat exchanger 100 may be something other than exhaust gas, for example. Similarly, the heat exchange medium flowing outside the plurality of flow path assemblies 130 of the heat exchanger 100 may be some other medium than cooling fluid piped in from the cooling loop of an internal combustion engine.