Patent Application
20070227140
The present disclosure relates to air-to-air aftercoolers, and more particularly, to flow tube designs for air-to-air aftercoolers.
Construction and earthmoving equipment, as well as many other types of machines, are commonly used in a wide variety of applications. Generally, such machines may be powered by an internal combustion engine. In order to optimize the performance of the machine, the engine should perform as efficiently as possible. Various methods have been developed to increase internal combustion engine efficiency. One method has been to incorporate a turbocharger into the internal combustion engine. The turbocharger may compress air prior to entering an engine intake or combustion chamber. Supplying the engine intake with compressed air (“charged air”) may allow for more complete combustion. This may result in lower emissions, improved performance, and better engine efficiency. However, compressing the air may also cause an increase in the intake air temperature. Supplying the engine intake with such heated charged air may lead to an undesirable increase in the amount of emissions exiting from the engine. Also, because engines may generally produce large quantities of heat already, adding heated charged air to the engine intake or combustion chamber may increase the operating temperature of the engine, thus resulting in excessive wear on engine components.
An air-to-air aftercooler (ATAAC) may be used to reduce smoke and other engine emissions by cooling the charged air before it enters the engine intake manifold. Using the ATAAC may also result in lower combustion temperatures, thus improving engine component life by reducing thermal stresses on the engine.
The ATAAC may include one or more tubes through which the heated charged air may pass. The outside of the tube may be subjected to some type of fluid, for example, ambient air, which may cool the tube. As the heated charged air passes through the tube, it may come into contact with the tube walls. Heat may be transferred from the charged air to the tube walls, and then from the tube walls into the ambient air, thus removing heat from the charged air. External fins may be added to the external surfaces of the tube walls to create greater surface area, which may provide improved heat transfer between the heated charged air and the ambient air.
In some traditional heat exchange systems, ATAAC components may be completely comprised of the same materials. One common material selection may include aluminum components having desired heat transfer properties. By way of example, these components may comprise tubings, fins, header assemblies, or manifolds. However, such aluminum components can be susceptible to corrosive effects within the operating environment. This can lead to shortened operational use of the ATAAC or require additional expense and/or downtime to service defective components of the ATAAC.
U.S. Pat. No. 5,730,213, issued to Kiser et al. (“Kiser”) discloses a heat exchanger having aluminum cooling tubes including a plurality of agitating dimples projecting into the interior surface of the tubes. The aluminum cooling tubes are sealed in a jointed connection at opposite tube ends to respective header plates. Aluminum fins are disposed between parallel aluminum cooling tubes to enhance heat transfer from the tubes. However, the heat exchanger design of Kiser et al. may not address corrosion issues that can result from using aluminum tubes in heat exchanger systems.
The present disclosure is directed towards overcoming one or more of the problems set forth above.
In one aspect, the present disclosure may be directed to an air-to-air aftercooler. The air-to-air aftercooler may include at least one tube body configured to direct a flow of charged air, wherein the at least one tube body includes a first material. The air-to-air aftercooler may also include a header assembly coupled to ends of the at least one tube body. The header assembly may include a second different material.
In another aspect, the present disclosure may be directed to a method of making an air-to-air aftercooler tube. The method may include providing at least one tube body formed of a first material, wherein the at least one tube body is configured to direct a flow of charged air. The method may also include coupling a header assembly, formed of a second different material, to ends of the at least one tube body.
In yet another aspect, the present disclosure may be directed to an engine assembly. The engine assembly may include a turbocharger configured to compress intake air before it enters an engine air intake manifold. The engine assembly may also include an air-to-air aftercooler operatively connected between the turbocharger and the engine air intake manifold. The air-to-air aftercooler may include at least one tube assembly configured to direct a flow of charged air. The at least one tube assembly may include a tube body, a first structure configured to promote mixing of charged air passing through the at least one tube assembly, and a second structure configured to promote mixing of charged air passing through the at least one tube assembly. The first structure may include a first material and the second structure may include a second different material. The air-to-air aftercooler may also include fins coupled to an exterior surface of the tube body, wherein the fins include the second material. The air-to-air aftercooler may also include a header assembly coupled to ends of the at least one tube assembly, wherein the header assembly includes the second material. Furthermore, the air-to-air aftercooler may also include a plurality of side sheets coupled to each header assembly, wherein the plurality of side sheets include a third material different than the first and second material. Finally, the air-to-air aftercooler may also include a manifold coupled to each header assembly, wherein the manifold comprises the third material.
Referring to
One or more engines 24 may be located within engine enclosure 18. An example of an engine 24 is shown in
Turbocharger 26 may include a compressor 30, powered by a turbine 28 driven by engine exhaust flow 34. The compressor 30 may pressurize intake air 38a to allow a greater mass of fuel/air mixture in the engine cylinders of engine 24. The result may be an increase in power and improved engine efficiency. However, as a byproduct of pressurization, the temperature of intake air 38a may also increase, which may be undesirable. The compressed intake air exiting compressor 30 may be referred to as heated charged air 38b. As noted above, heated charged air 38b may be cooled prior to entering air intake manifold by passing through ATAAC 36.
One exemplary disclosed embodiment of ATAAC 36 is shown in
In the exemplary disclosed embodiment shown in
The present disclosure includes the use of selected materials for the ATAAC 36 system. For example, stainless steel material may be utilized within ATAAC 36 in order to provide an amount of corrosion resistance to the overall design of the heat exchange system. A complete use of stainless steel components in ATAAC 36, however, may make the overall weight of the ATAAC 36 unacceptable. Hence, the use of lighter materials, such as aluminum, for other components of the ATAAC 36 may be desirable. The use of other materials, such as aluminum, in additional components may also facilitate achieving a desired cooling performance of ATAAC 36. Hence, as will be described in more detail below, the disclosed ATAAC 36 may be constructed of stainless steel material in combination with aluminum components. For example, in some disclosed embodiments, stainless steel components of ATAAC 36 may comprise tubes 44. Additionally, aluminum components of ATAAC 36 may comprise headers 54, external fins 50, side sheets 52, inlet manifold 42, and outlet manifold 48. While certain components, such as tubes 44, headers 54, external fins 50, side sheets 52, inlet manifold 42, and outlet manifold 48 of ATAAC 36, have been identified as including certain materials, the aforementioned components are not limited to these materials as individual components or collectively assembled within a final ATAAC 36 configuration. Selection of materials for various components, including, for example, tubes 44, headers 54, external fins 50, side sheets 52, inlet manifold 42, and outlet manifold 48 may vary based upon an overall consideration of the final ATAAC 36 assembly which balances, for example, a plurality of factors such as weight preferences, cooling performance, and resistance to corrosion. Hence, the combination of mixed components may provide superior performance by increasing cooling performance and reducing corrosion tendencies while, at the same time, addressing weight concerns and/or neutralizing condensation effects within ATAAC 36.
The use of components, for example, those including dissimilar materials, in the ATAAC design may present additional challenges for securing the dissimilar materials together in a final assembly. For example, some assembly operations for securing individual components of dissimilar materials, such as in an ATAAC design, may not meet prescribed production requirements. Hence, a method of the present disclosure may address assembly operations by providing materials which can make assembly of ATAAC 36 more efficient and/or cost effective.
The present disclosure may include a one-operation process for joining dissimilar materials to form a rigid assembly of components. One such method may include brazing or joining of metals through the use of heat and a filler metal (e.g., one whose melting temperature is above 840° F. (450° C.) but below the melting point of the metals being joined). The tensile strength of the brazed joint may exceed that of the metals being joined. In addition, brazed joints are generally ductile, i.e., generally able to withstand considerable shock and vibration such as those which may be generated during operation of machine 10.
In comparison with other joining operations, such as welding, for example, brazing requires relatively low temperatures for joining dissimilar materials. This may prevent overheating or melting the dissimilar materials, such as metals being joined, which could possibly distort or warp the base materials around the joined area. For relatively thin materials, for example, such as tubes 44 or external fins 50 (
The generation of higher temperatures (such as those produced by welding) may generally translate into higher operating costs (due to higher energy consumption). Employing brazing operations to ATAAC 36 assemblies may reduce operating expenditures since less heat would be required in brazing processes. Furthermore, brazed joints and/or assemblies generally produce good appearances. This may eliminate, or greatly reduce, additional finishing operations and associated expenditures.
Brazing operations may also be relatively easy to automate since, for example, a characteristic of brazing does not require precise synchronization of heat application and deposition of filler metal (such as is required in welding). Brazing operations are generally facilitated by broad heat applications and the ease of positioning a filler material. One of many methods for automatically providing heat to a joint may be employed. Additionally, the disclosed embodiment may utilized one of many available brazing layers or cladding as filler materials. Furthermore, a variety of methods for depositing filler metal materials may also be utilized. For example, in some embodiments, components of ATAAC 36 may contain aluminum cladding or a brazing layer. By utilizing these materials, manufacturing processes of the ATAAC design may be simplified such as by reducing assembly times in more simplified or reduced brazing operations. Furthermore, the resulting structure of ATAAC 36, in accordance with the present disclosure, may also provide increased strength of rigid connections of the components, thus, ensuing increased strength of the final assembly.
In one exemplary disclosed embodiment, tubes 44 are shown enlarged in
Turning to
Each tube 44 may also include one or more devices to promote mixing of heated charged air 38b passing through tube 44. The aforementioned devices may include relatively thin strips of metal material, bent or otherwise formed into desired configurations and located within an interior 47 of tube 44 (
Both first turbulator 62 and second turbulator 64 may be formed into configurations for promoting mixing of heated charged air 38b passing through tube 44. For example, a final configuration of first turbulator 62 may include a bent “L” configuration over a width “w1”. Outer edges “e1” run along width “w1” of first turbulator 62. First turbulator 62 may also have an associated thickness covering a length “I1”. A final configuration of second turbulator 64 may include multiple bends forming a plurality of “U” configurations over a width “w2”. Outer edges “e2” run along width “w2” of second turbulator 64. The length of the plurality of“U” configurations may traverse a distance “12”. In the embodiment shown, the thickness or length “11” of first turbulator 62 is shorter than the thickness or length “12” of second turbulator 64.
First turbulator 62 and second turbulator 64 may be combined to form patterns of turbulators inside tube 44. Hence, a final turbulator assembly disposed interior to tube 44 may create a final tube assembly 72 (
An alternative configuration of a final turbulator assembly is shown in
Once the final turbulator assembly is encapsulated by first C-channel 56 and second C-channel 58 to form final tube assembly 72, a brazing operation may be implemented to rigidly retain the final turbulator assembly (e.g., first turbulator assembly 61 and second turbulator assembly 63) within first C-channel 56 and second C-channel 58. For example, brazing may occur along a surface of first turbulator 62 (including stainless steel with aluminum cladding) and an abutting surface of the second turbulator 64 (including aluminum with a brazing layer). Likewise, brazing may occur along a surface of first turbulator 62 (including stainless steel with aluminum cladding) and an abutting surface of first C-channel 56 (including aluminum cladded stainless steel) and second C-channel 58 (including aluminum cladded stainless steel). Furthermore, brazing may occur along a surface of second turbulator 64 (including aluminum with a brazing layer) and an abutting surface of first C-channel 56 and second C-channel 58 (including aluminum cladded stainless steel.)
The brazing operation may also serve to rigidly connect abutting surfaces of first C-channel 56 (including aluminum cladded stainless steel) and second C-channel 58 (including aluminum cladded stainless steel) to facilitate forming the final tube assembly 72. Alternatively, other processes suitable for rigidly connecting the abutting surfaces of first C-channel 56 and second C-channel 58 may be used. In one exemplary embodiment, for example, the aforementioned abutting surfaces may be connected by a laser welding operation.
Turning to
In some embodiments, a dimple 70 may be provided in modular header 66 to provide an added measure of strength to the overall header design. Modular headers 66 may also include machined slots 68 such as for receiving an end portion 74 of final tube assembly 72 in a final assembly. As shown in
Turning to
As previously discussed, the brazing operation simplifies the manufacturing process of ATAAC 36 by reducing assembly times in more simplified or reduced brazing operations. For example, a final turbulator assembly may be disposed within final tube assemblies 72. End portions 74 of each final tube assembly 72 may be disposed in machined slots 68 (of modular header assembly 67) or 77, 79 (of split header assembly 80). Fins 50 may be abutted with final tube assemblies 72. Hence, each of the final turbulator assemblies within final tube assemblies 72, the final tube assemblies 72, the modular header assembly 67 or split header assembly 80, and fins 50 may be joined together in one brazing operation to form ATAAC 36 (as opposed to individually assembling each of the components together). This method of manufacture simplifies construction of ATAAC 36 by reducing an amount of assembly steps and any associated costs which would otherwise be attributable for performing those steps. Moreover, the resulting structure of ATAAC 36, in accordance to the present disclosure, may also provide increased strength of rigid connections of the components, thus, ensuing increased strength of the final assembly. This structure may also be less susceptible to corrosion effects in operation and provide an ATAAC 36 assembly within prescribe weight tolerances.
Turning to
Turning to
Industrial Aipplicability
The disclosed ATAAC may have applicability in any system requiring the cooling of a fluid. For example, the disclosed ATAAC may be used in connection with internal combustion engines. In particular, and as shown in
In a machine 10, exhaust 34 leaving engine 24 may be directed towards a turbine 28 of turbocharger 26. The flow of exhaust 34 may power turbine 28, causing it to rotate and drive compressor 30. Intake air 38a may be directed into compressor 30 where it may undergo compression, and as a byproduct of compression, intake air 38a may also be heated into heated charged air 38b. Heated charged air 38b may travel from compressor 30 into ATAAC 36 through an inlet 40, where it may be directed into an intake manifold 42. As shown in
As noted above, the selected materials of the disclosed ATAAC 36 system may also provide advantages. For example, the majority of components in traditional heat exchange systems are typically formed of an aluminum material. These aluminum components, such as tubing connected to header assemblies, may be susceptible to corrosion over a period of time. In the disclosed embodiment, stainless steel material may be utilized within ATAAC 36 in order to provide an amount of corrosion resistance to the overall design of the heat exchange system. The use of lighter materials, such as aluminum, for other components of the ATAAC 36 may be desirable, for instance, to maintain a weight requirement of ATAAC 36. Additionally, constructing additional components from aluminum material may also facilitate achieving a desired cooling performance of ATAAC 36. Selection of materials for various components, including, for example, tubes 44, headers 54, and external fins 50, may vary based upon an overall consideration of the final ATAAC 36 assembly which balances, for example, a plurality of factors such as weight preferences, cooling performance, and resistance to corrosion.
Hence, one embodiment of the disclosed ATAAC 36 includes a combination of materials including, for example, stainless steel and aluminum components. A mix of stainless steel (e.g., to provide corrosion resistance) in combination with aluminum (e.g., to provide a high cooling performance) may serve to address an overall durability of the ATAAC 36 design while also ensuring a prescribed or practical weight range of the assembled ATAAC 36. The combination of mixed components, such as utilizing stainless steel tubes 44, a stainless steel turbulator 62, an aluminum turbulator 64, aluminum fins 50, aluminum side sheets 52, aluminum headers 67 or 80, aluminum inlet manifold 42, and aluminum outlet manifold 48 may provide superior performance by increasing cooling performance, reducing corrosion, reducing weight, and neutralizing condensation effects within ATAAC 36.
The disclosed ATAAC 36 not only addresses durability concerns, but also provides an improved assembly process for producing heat exchanger system in an efficient manner. This, too, may be facilitated through the selection of materials in the disclosed ATAAC 36 design. For instance, because the selected materials may contain aluminum cladding or a brazing layer, manufacture of the disclosed ATAAC 36 design may be simplified such as by assembling multiple components in one operating process—a process which may be yielded by employing a single brazing operation. This, in effect, may reduce assembly times and tend to increase overall production goals of ATAAC 36 assemblies.
In some embodiments, the brazing operation may supplement other assembly processes including, for example, formation of a final assembly such as ATAAC 36. This may include, for example, providing previously assembled components, such as first C-channel 56 rigidly connected to second C-channel 58 to form unitary tube body 60. (In one exemplary embodiment, a suitable connecting process may include laser-welding.) Hence, a combination of mixed components, such as pre-assembled tube body 60, stainless steel turbulators 62, aluminum turbulators 64, aluminum fins 50, aluminum side sheets 52, aluminum headers 67 or 80, aluminum inlet manifold 42, and aluminum outlet manifold 48, may be assembled and subsequently subjected to a brazing operation. Thus, the brazing operation may be useful in simplifying a final assembly operation for connecting one or more pre-assembled components with some individual components including, for example, ATAAC 36.
Additional advantages provided in the selection of materials for a brazing operation may include producing a final ATAAC 36 assembly at relatively low temperatures for joining dissimilar metal materials. This may reduce or eliminate undesirable metal distortions or warping effects of the assembled components. Since the tensile strength of brazed joints may exceed that of the metals joined, the selection of materials (for example, the aluminum cladding of the stainless steel tubing as well as on the aluminum components) may be important to increasing the overall strength of the ATAAC 36 assembly. Hence, the selection of materials of the resulting structure utilized in the disclosed ATAAC 35 may also provide increased strength to rigid connections of the components. The rigid connections may further ensure an increased strength of the final ATAAC 36 assembly.
Turbulators 62, 64 may also provide added structural strength. As discussed above, first turbulator 62 and second turbulator 64 may be combined to form patterns for a final turbulator assembly within tube 44. Contact between turbulators 62, 64 and internal receiving regions 57, 59 of tube 44 may resist external forces on tube 44 that would otherwise cause tube 44 to inwardly deform. Additionally, internal pressure within tube 44 may be less likely to cause outward deformation of walls of tube 44 when turbulators 62, 64 are secured thereto. As a result, ATAAC 36 may be used in engine assemblies with high charge air pressures. The ability to use higher charge air pressures may provide the added benefits of more complete combustion of fuel, lower emissions, and greater overall engine efficiency.
It will be apparent to those skilled in the art that various modifications and variations can be made in the disclosed ATAAC and methods without departing from the scope of the disclosure. Additionally, other embodiments of the ATAAC will be apparent to those skilled in the art from consideration of the specification. It is intended that the specification and examples be considered as exemplary only, with a true scope of the disclosure being indicated by the following claims and their equivalents.
