INTERNAL HEAT EXCHANGER

TECHNICAL FIELD

[0001] The present disclosure relates to an internal heat exchanger, and more particularly to a double tube internal heat exchanger for a vehicle.

BACKGROUND

[0002] Internal heat exchanger assemblies are now being used on vehicle air conditioning systems to improve performance and system efficiency.

Efficiency and performance gains are achieved by the use of a coaxial heat exchanger where the liquid refrigerant is flowed around the outside of the suction tube. Heat is transferred from the liquid to the suction line which increases sub-cooling in the liquid line.

SUMMARY

[0003] The present invention includes an internal heat exchanger for a vehicle with improved suction line flow. The internal heat exchanger has an inner tube and an outer tube. The inner tube and outer tube are coaxial with one another. A flow enhancer is disposed within the inner tube to divert flow of fluid towards an outer wall of the inner tube. The flow diversion aids in the transfer of heat to the outer wall thereby improving the efficiency of the heat exchanger. [0004] The flow enhancer may be an elongate shape and may be formed, for example, from an extrusion process. The flow enhancer can be shaped so as to divert flow towards the outer wall of the inner tube while blocking the flow of fluid from the middle of the tube. For example, the flow enhancer may be an elongate member having a generally cylindrical central portion and a plurality of radially extending longitudinal fins.

BRIEF DESCRIPTION OF THE DRAWINGS

[0005] Embodiments of this invention will now be described in further detail with reference to the accompanying drawings, in which:

[0006] FIG. 1 is an spring internal heat exchanger.

[0007] F!G. 2 A shows a view of a multi-channel internal heat exchanger.

[0008] FIG. 2B shows a section along line 2B-2B of FIG. 2A.

[0009] FIG. 2C shows a view of a multi-channel internal heat exchanger.

[0010] FIG. 3A is an exemplary embodiment of a flow enhancer in

accordance with aspects of the invention.

[0011] FIG. 3B is an exemplary embodiment of a suction tube.

[0012] FIG. 3C is an exemplary embodiment of an assembly of the flow enhancer and suction tube of FIGS. 3A and 3B.

[0013] FIG. 4A is an exemplary embodiment of an assembly of a flow enhancer, a suction tube and a liquid tube of a channel internal heat exchanger. [0014] FIG. 4B is an exemplary embodiment of an assembly of a flow enhancer, a suction tube and a liquid tube of a spring internal heat exchanger.

[0015] FIG. 5A is an exemplary embodiment of a spring internal heat exchanger having a flow enhancer.

[0016] FIG. 5B is an exemplary embodiment of a channel internal heat exchanger having a flow enhancer.

DETAILED DESCRIPTION OF THE DRAWING

[0017] FIG. 1 is an exemplary spring internal heat exchanger 10. FIGS. 2A to 2C show various views of an exemplary channel heat exchanger 20. Both heat exchangers 10, 20 comprise an inner tube 30 and an outer tube 32 that are coaxial with one another. The inner tube 30 is the return line (also referred to as a "suction line") of a refrigeration system. The inner tube 30 and outer tube 32 are separated by a passageway. In the spring heat exchanger 20, the inner tube 30 and outer tube 32 are separated by a spring 34 forming a helical passageway 50 between the tubes. In the channel heat exchanger 30, the inner tube 30 and outer tube 32 are separated by a plurality of ribs 36 that form one or more channel-shaped passageways 38.

[0018] Referring now to FIGS. 3A to 3C, the heat exchangers 20, 30 are shown with a flow enhancer 50. The flow enhancer 50 may be an elongate member. The elongate member may be formed by an extrusion process. As shown best in FIG. 3A, the flow enhancer 50 has a central portion 52 that extends axially and a plurality of radial members 52 (for example, ribs) that extend along the axial length of the flow enhancer, in one embodiment, at least one radial member can be a continuous fin that extends along the full axiai length of the flow enhancer. Additionally or alternatively, the flow enhancer may include a plurality of fins that extend along a portion of an axiai length of the flow enhancer (e.g., less than the full axial length of the flow enhancer).

[0019] The central portion 52 may have a substantially circular cross- section. The flow enhancer 50 is assembled with the inner tube 30 such that the flow enhancer 50 and inner tube 30 are coaxial with one another. The outer portions 54 of the radial members 52 may be in contact with the inner tube 30, as shown in FIG. 3C.

[0020] The flow enhancer 50, and in particular, the central portion 52, blocks flow in the center of the inner tube 30 (suction tube) and diverts or forces the flow against a wall 51 of the tube 30. The central portion 52 and radial members 54 can be configured to minimize pressure drop across the internal heat exchanger. The flow enhancer may be formed from a composite material that is may be bendable with the inner and outer tubes, in one embodiment, the flow enhancer is constructed from a composite material that does not substantially affect heat transfer.

[0021] Referring still to FIGS. 3A to 3C, the material can, for example, also be composite plastic, nylon or any metal such as aluminum, copper or a combination of metal and plastic. The rib design may or may not be continuous. [0022] FIG. 4A is an embodiment of an assembly of a flow enhancer, a suction tube and a liquid tube of a channel internal heat exchanger wherein the rib edge is in contact with the suction tube inner diameter. FIG. 4B is an embodiment of an assembly of a flow enhancer, a suction tube and a liquid tube of a spring internal heat exchanger wherein the rib edge is in contact with the suction tube inner diameter.

[0023] FIG. 5A is an embodiment of a spring internal heat exchanger having a flow enhancer and FIG. 5B is an embodiment of a channel internal heat exchanger having a flow enhancer.

[0024] Although the principles, embodiments and operation of the present invention have been described in detail herein, this is not to be construed as being limited to the particular illustrative forms disclosed. They will thus become apparent to those skilled in the art that various modifications of the embodiments herein can be made without departing from the spirit or scope of the invention.