AIR-COOLED CHARGE AIR COOLER WITH COOLING ELEMENT

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of the following U.S. Provisional Patent Applications: Application Serial Number 60/736,371 , filed on

November 14, 2005, entitled AIR-COOLED CHARGE AIR COOLER WiTH A COOLING AiR BYPASS PASSAGEWAY; Application Serial Number 60/736,381 filed on November 14, 2005, entitled AIR-COOLED CHARGE AIR COOLER WITH AN INTERNAL ENGINE COOLANT MANIFOLD and Application Serial Number 60/736,382 filed on November 14, 2005, entitled AIR-COOLED CHARGE AIR COOLER WITH AN EXTERNAL ENGINE COOLANT MANIFOLD; all of which are hereby incorporated herein by reference,

TECHNICAL FIELD

The present invention relates to the art of heat transfer; more particularly, to air-cooled charge air coolers; and most particularly to air- cooled charge air coolers for cooling air from a turbocharger before it enters an engine.

BACKGROUND OF THE INVENTION

In order to maximize performance, diesel engines use turbochargers to compress the combustion air, thus increasing its density, and increasing the amount of oxygen available for combustion in the engine. During the course of compression, the temperature of the charge air is increased. Charge air coolers are heat exchangers that cool the charge air to further increase its density before the charge air enters the engine.

As environmental concerns have emerged, governments have placed limits on emissions from diesei engines. These limits have become more and

more restrictive. In order to meet these emission regulations, diesel engine designers have increased charge air pressures and temperatures.

A common air-cooied charge air cooler is made from aluminum, either tube and header designs or bar and plate designs. These heat exchangers have maximum temperature and pressure limits resulting from design considerations including the maximum allowable stress of aluminum at operating temperatures. The tensile strength of aluminum begins to decrease considerably above about 300 ⁰ F to 400°F. This means that the product must use heavier parts in order to contain the charge air pressure without failure. Bar and plate designs tend to be more robust than tube and header designs. Even so, the inlet manifold and the inlet ends of the charge air passages are subject to the maximum charge air temperature. Some engine designs result in specifications of charge air temperatures of 500 ⁰ F or higher with operating pressures of 50 psig or higher. However, it is true that the metal temperature will be somewhat lower than the charge air inlet temperature due to heat transfer between the manifold and the ambient surrounding the charge air cooler. This temperature, which may be 50 to 75 ⁰ F lower than the inlet temperature, is still high enough to require the use of low allowable stresses for design of the charge air cooler. What is needed is a means of lowering the charge air cooler metal temperature significantly more than about 50 ⁰ F to 75°F (28 ⁰ C to 42 ⁰ C) so that much higher stresses can be used for design purposes.

It is a primary object of the invention to lower the charge air cooler metal temperature significantly more than 50 ⁰ F to 75 ⁰ F so that much higher stresses can be used for design purposes.

SUMMARY OF THE INVENTION

Briefly described, an apparatus for cooling an intake manifold of a heat exchanger includes a cooling element that is in thermal contact with the intake manifold and wherein cooling ffuid (a gas or a liquid or mixtures thereof)

is passed through said cooling element. The cooling element is capable of reducing the temperature of the intake manifold below the temperature at which the tensile strength of said intake manifold begins to weaken significantly. In one embodiment the cooling element includes a manifold adapted to circulate coolant from an engine's cooling system through the manifold. In another embodiment, the manifold is an internal manifold. In an alternative embodiment, the manifold is an externa! manifold. In a further embodiment, the cooling element comprises an enclosure adapted to be attached to a core of the heat exchanger, said enclosure further adapted to at least partially enclose and be spaced apart from two sides and a top of the intake manifold to form a fluid passageway between the intake manifold and the enclosure.

Also briefly described are methods of cooling an intake manifold of a heat exchanger. One embodiment includes placing a cooling element in thermal contact with high temperature charge air, wherein said cooling element is adapted to circulate coolant from an _^ engine's cooling system through said cooling element, and passing an engine coolant through the cooling element. In another embodiment, the cooling element is an internal manifold, in a further embodiment, the cooling element is an external manifold.

Another method of cooling an intake manifold includes placing a cooling element in thermal contact with high temperature charge air, wherein said cooling element comprises an enclosure adapted to be attached to a core of said heat exchanger, said enclosure further adapted to at least partially enclose and be spaced apart from two sides and a top of said intake manifold to form a fluid passageway between said intake manifold and said enclosure, and passing a cooling fluid through said fluid passageway, said cooling fluid being a portion of the cooling fluid supplied to said heat exchanger for cooling a warmer fluid flowing through said intake manifold into a core of said heat exchanger.

BRIEF DESCRlPTtOM OF THE DRAWINGS

The present invention wilf now be described, by way of example, with reference to the accompanying drawings, in which: FlG. 1 is a perspective view of a preferred embodiment of a portion of an air-cooled charge air cooler with a cooling air bypass channel according to the present invention;

FIG. 2 is a side view of an air-cooled charge air cooler which includes the portion of the air-cooled charge air cooler of FIG. 1 with a turbocharger or supercharger;

FIG. 3 is a cross sectional view of a smaller portion of the air-cooled charge air cooler of FiG. 1 ;

FlG. 4A is a top view of the enclosure shown in F?G, 1 ; FIG. 4B is a front view of the enclosure shown in FIG. 1 ; FlG. 4C is a side view of the enclosure shown in FlG. 1 ;

FiG. 5 is a plan view of the blank used to form the enclosure shown in FiG. 1 ;

FIG. 6A is a front view of a preferred embodiment of an air-cooted charge air cooler with an internal engine coolant manifold according to the present invention;

FIG. 6B is a top view of the air-cooled charge air cooler with an interna) engine coolant manifold of FlG. 6A with an engine coolant system and a supercharger or turbocharger;

FIG. 6C is a side view of the air-cooled charge air cooler with an internal engine coolant manifold of FIG. 6A;

FlG. 7A is a front view of a preferred embodiment of an internal engine coolant manifold according to the present invention;

FiG, 7B is a top view of the internal engine coolant manifold of FiG. 7A; FlG. 7C is a side view of the internal engine coolant manifold of F)G. 7A;

FiG. 8A is a front view of a preferred embodiment of an air-cooled charge air cooler with an external engine coolant manifold according to the present invention;

FIG. 8 B is a top view of the air-cooied charge air cooler with an externa! engine coolant manifold of FIG. 8A with an engine coolant system and a supercharger or turbocharger; and

FIG. 8C is a side view of the air-cooled charge air cooler with an external engine coolant manifold of FIG. 8A.

It will be appreciated that for purposes of clarity and where deemed appropriate, reference numerals have often been repeated in the figures to indicate corresponding features, and that the various elements in the drawings have not necessarily been drawn to scale in order to better show the features of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Turning now to the drawings, FlG. 1 is a perspective view of a portion of an air-cooled charge air cooler 10, suitable for use with high temperature, high pressure outlet air from a turbocharger or supercharger. The air-cooled charge air cooler portion 10 has an intake manifold 12, including an intake hose connector 14, a bar and plate heat exchanger 16 including end plates 18 and 20, and a cooling air bypass enclosure 22. The intake hose connector 14 has a raised ring 24 for retaining a hose (not shown) onto the intake hose connector 14.

In operation, high temperature, high pressure charge air enters the intake hose connector 14, flows into the bar and plate heat exchanger 16 through the intake manifold 12. As stated in the Background of the Invention section above, the high pressure, high temperature charge air entering the intake manifold 12 would normally require thicker wails in the intake manifold and in the heat exchanger, or, alternatively, higher temperature metals, to accommodate the high pressure, high temperature combination. Both of

these alternatives have at least one disadvantage compared to conventiona! bar and plate heat exchangers which can operate reliably with lower pressures and/or lower temperatures. The cooling air bypass enclosure 22 allows a conventional heat exchanger to be used with the high pressure, high temperature charge air.

FIG. 2 is a side view of an air-cooled charge air cooler 26 which includes the portion of the air-cooled charge air cooler of FIG. 1 , and also includes an outlet manifold 28 having an outlet hose connector 30. The outlet hose connector 30 has a raised ring 31 for retaining a hose (not shown) onto the outlet hose connector 30. Also shown in FlG. 2 is a turbocharger or supercharger 32 having a hose 34 for passing the high temperature, high pressure charge air from the turbocharger 32 to the air-cooled charge air cooler 10. The hose 34 is held in place on the inlet hose manifold 14 by a clamp 36. As shown in FlG. 2, the cooiing air bypass enclosure 22 is wider and higher than the intake manifold 12 such that an air gap 38 (shown in FIG. 3} is formed for passage of cooling air 40 (indicated by the arrows) from the cooling air intake side of the bar and plate heat exchanger 16 to the cooling air output side of the bar and plate heat exchanger 16. The cooling air 40 flowing through the air gap 38 cools the sides and top of the intake manifold 12 which, in turn, cool the intake air at the intake hose connector 14. The width of the gap 38 is determined by the degree to which the input air needs to be cooled and the flow rate and temperature of the cooling air 40. In the preferred embodiment the gap 38 is about 0.25 in. (0.6 cm) and, as a result, even though the charge air at the Intake hose connector 14 is about 500 ⁰ F, the mean temperature of the walls of the intake manifold 12 are in the range of 250 ⁰ F to 350 ⁰ F which is also the mean temperature at the interface between the intake manifold 12 and the heat exchanger 16. This temperature range of 250 ⁰ F to 35O ⁰ F is well within the design range for the conventional intake manifold 12 and conventional aluminum bar and plate heat exchanger

16. This lower temperature allows the use of much higher stresses for design purposes.

Also shown in FlG. 2 are side strips 42, 44, and 48 of the enclosure 22 which are formed by folding a sheet metal blank 50 shown in FIG. 5. The bottoms of the strips 42 and 48 are attached to top of the end p!ate 18 of the heat exchanger 16 to hold the enclosure 22 in place.

FJG. 3 is a cross section of the upper portion of the portion of the air- cooled charge air cooler 10 of FlG.1 showing the air gap 38 around the sides and top of the enclosure 22. FiGs. 4A, 4B, and 4C are top, front, and side views, respectively, of the enclosure 22. The side view of FIG. 4C shows side strips 52, 54, and 56 on the right end of the enclosure 22. The bottoms of the side strips 52 and 56 are attached to the top of the side panel 20 when the charge air cooler 26 is assembled to hold the enclosure 22 in place. FlG. 5 is a plan view of the blank 50 used to form the enclosure 22 by bending the blank along the bend lines 58 to form the enclosure 22,

In the preferred embodiment the joint between the internal passages of the intake manifold 12 and the sheets between the header bars and face bars of the heat exchanger 16 operate at a lower temperature than the air entering the intake hose connector 14 due to the conduction of heat from the header bars of the heat exchanger 16 to the sides of the intake manifold 12 which, in turn, are cooled by the cooling air 40 present at the cooling air intake side of the charge air cooler 26.

Turning again to the drawings, FlGs. 6A, 6B, and 6G are front, top, and side views, respectively, of a preferred embodiment according to the present invention including an air-cooled charge air cooler 210 with an internal engine coolant manifofd 226. The air-cooled charge air cooler 210 has an inlet ^" manifold 212, including a hose connector 214 with a raised ring 216 for retaining a hose onto the hose connector 214, a bar and plate heat exchanger core 218, an outlet manifold 220, including a hose connector 222 with a raised

ring 224 for retaining a hose onto the hose connector 222, and an interna] engine coolant manifold 226 which is in heat transfer relationship with the sides of the inlet manifold 212. The internal engine coolant manifold 226, which in the preferred embodiment is welded to the sides of the intake manifold 212, has connections 228 for engine coolant to enter and leave the internal engine coolant manifold 226 along its length. The size of the air- cooled charge air cooler 210 and the temperature of the inlet air to the intake manifold 212 determine the size of the internal engine coolant manifold 226 and the quantity of engine coolant required, FlG. 6B shows an engine coolant system 232 connected by coolant hoses 234 to the connections 228 of the internal engine coolant manifold 226, and a supercharger or turbocharger 236 that exhausts high pressure, high temperature charge air into the intake manifold 212 through a hose 238 held in place by a clamp 240. FIGs. 7A, 7B, and 7C are front, top, and side views, respectively, of the internal engine coolant manifold 226 shown in FIGs. 6A, 6B, and 6C. In the preferred embodiment the interna! engine coolant manifold 226 is made by bending a long tube into the coil shape shown such that the sides of the coil are in contact with the infernal sides of the intake manifold 212. In operation the engine coolant circulated through the interna! engine coolant manifold 226 by the engine coolant system 232 removes heat from the interna) engine coolant manifold 226 surfaces, effectively lowering its temperature. Even though the internal engine coolant manifold 226 is in contact with only a portion of the sides of the inlet manifold 212, heat is removed by conduction from the entire inlet manifold 212. Thus the mean temperature of the inlet manifold 212 is reduced. As stated in the Background of the Invention section above, the high pressure, hfgh temperature charge air entering the inlet manifold 212 would normally require thicker walls in the inlet manifold 212 and in the heat exchanger 218, or, alternatively, higher temperature metals, to accommodate the high pressure, high temperature

combination. Both of these alternatives have at least one disadvantage compared to conventional bar and plate heat exchangers which can operate reliably with lower pressures and/or lower temperatures. The internal engine coolant manifold 226 allows a conventional brazed heat exchanger to be used with the hfgh pressure, high temperature charge air. in the preferred embodiment the joint between the internal passages of the inlet manifold 212 and the sheets between the header bars and face bars of the heat exchanger 218 operate at a lower temperature than the air entering the hose connector 214 due to the conduction of heat from the header bars of the heat exchanger 218 to the sides of the inlet manifoid 212 which, in turn, are cooled by the internal engine coolant manifold 226.

Turning again to the drawings, FIGs. 8A, 8B, and 8C are front, top, and side views, respectively, of a preferred embodiment of an air-cooled charge air cooler according to the present invention including an external engine coolant manifold 326. The air-cooled charge air cooler 310 has an inlet manifold 312, including an inlet hose connector 314 with a raised ring 316 for retaining a hose onto the inlet hose connector 314, a bar and plate heat exchanger core 318, an outiet manifold 320, including a hose connector 322 with a raised ring 324 for retaining a hose onto the hose connector 322, and an external engine coolant manifold 326 which is in heat transfer relationship with the outside top surface of the inlet manifold 312. The external engine coolant manifold 326, which in the preferred embodiment is welded to the top of the intake manifoid 312, has connections 328 for engine coolant to enter and leave the external engine coolant manifold 326. A partition 330 in the middle of the external engine coolant manifold 326 forms a passageway inside the external engine coolant manifold 326 so that the engine cooiant circulates past the walls of the external engine coolant manifold 326, The size of the air-cooled charge air cooler 310 and the temperature of the inlet air to the intake manifoid 312 determine the size of the external engine coolant manifold 326 and the quantity of engine coolant required. Advantageously,

the external engine manifold 326, by being placed on top of the inlet manifold 312, provides a centrally located heat sink for the housing of the inlet manifold 312.

FIG. 8B also shows an engine coolant system 332 connected by coolant hoses 334 to the connections 328 of the externa! engine coolant manifold 326, and a supercharger or turbocharger 336 that exhausts high pressure, high temperature charge air into the inlake manifold 312 through a hose 338 held in place by a clamp 340.

In operation the engine coolant circulated through the external engine coolant manifold 326 by the engine coolant system 332 removes heat from the external engine coolant manifold 326 surfaces, effectively lowering its temperature. Even though the external engine coolant manifold 326 is in contact with oniy the top of the inlet manifold 312, heat is removed by conduction from the housing of the entire inlet manifold 312. Thus the mean temperature of the inlet manifold is reduced. As stated in the Background of the Invention section above, the high pressure, high temperature charge air entering the inlet manifold 312 would normally require thicker walls in the iniet manifold 312 and in the heat exchanger 318, or, alternatively, higher temperature metals, to accommodate the high pressure, high temperature combination. Both of these alternatives have at least one disadvantage compared to conventional bar and plate heat exchangers which can operate reliably with lower pressures and/or lower temperatures. The external engine coolant manifold 326 allows a conventional brazed heat exchanger to be used to cool high pressure, high temperature charge air. In the preferred embodiment the joint between the internal passages of the inlet manifold 312 and the sheets between the header bars and face bars of the heat exchanger 318 operate at a lower temperature than the air entering the inlet hose connector 314 due to the conduction of heat from the header bars of the heat exchanger 318 to the sides of the inlet manifold 312 which, in turn, are cooled by the external engine coolant manifold 326.

Although the external engine coolant manifold 326 is separately fabricated and then welded to the intake manifold 312 in the preferred embodiment, the external engine coolant manifold 326 could be formed as an integral part of the intake manifold 312. While the invention has been described by reference to various specific embodiments, it should be understood that numerous changes may be made within the spirit and scope of the inventive concepts described. Accordingly, it is intended that the invention not be limited to the described embodiments, but will have full scope defined by the language of the following claims. For example, although the preferred embodiment described above operates to cool high temperature, high pressure charge air, the present invention is also applicable to heat exchangers that cool liquids.