Patent Grant
7506618
1. Field of the Invention
The present invention relates to a split heat exchanger, and particularly to a radiator with maximized entering temperature differentials for both at least one charge air cooler and a jacket water cooler.
2. Description of the Related Art
It is well known that heat energy contained in one fluid is capable of being transferred to another fluid. Such heat transfer is described in the classical heat transfer equation: Q=UAdT. In this equation, Q represents the heat transfer, U represents a coefficient of heat transfer, A represents the surface area through which the heat can be transferred, and dT represents the change in temperatures between the two mediums. Heat exchangers, and radiators in particular, are designed for a relative high level of transfer of heat energy from one medium to another. One common example is an automobile radiator, in which a coolant fluid passes through an engine to absorb heat energy from the engine. The coolant fluid then is routed through the radiator, where heat is transferred from the coolant fluid to the environment (ambient air).
Engineers and designers have incorporated many strategies to increase the amount of heat that a heat exchanger is capable of transferring. One strategy is to attempt to increase the coefficient of heat transfer. Design components, such as the incorporation of louvers, dimples, waves, ridges and other alterations to the fin profiles have been effectively used. While these improvements are quantifiable and generally useful, there are limitations (both practical and theoretical) as to how much the coefficient of heat transfer can be improved. For example, the increased tooling costs may overshadow any savings associated with the increased coefficient. Accordingly, it may take a long time to recapture those costs through efficiency savings, if it is even possible at all.
Others have had success in increasing the heat transferring capability of the heat exchanger by increasing the surface area between the two mediums (i.e. increasing the size of the heat exchanger). The increases in surface area can come from a combination of increases in height, width, depth and density of the heat exchanger. Often times, the size requirements for shipping and use dictate maximum dimensions in the height and width dimensions. In such situations, the only remaining variable is the depth of the unit. Accordingly, designers have increased the depth of the heat exchanger in order to increase the surface area.
Some heat exchangers are designed for use with engines having turbochargers. It is standard practice to stack two or more radiators in series to cool both a jacket water coolant from the engine and charge air compressed by one or more turbochargers. One configuration has a charge air cooler first, and ajacket water cooler second. Put another way, the charge air cooler is upstream of the jacket water cooler in some configurations, such that air first passes through the charge air cooler and second through the jacket water cooler. There are several drawbacks associated with such standard arrangements.
First, having a series stacked heat exchanger has a depth that is equal to the depth of both the jacket water cooler and the charge air cooler. Such a design has a depth that is often greater than that of a single radiator. Any additional depth can increase the system resistance, which is caused when pressure develops between the fan or air mover and the rear side (down stream side) of the jacket water cooler. Pressure can develop by expansion of the air as it gains energy from the heat exchanger, and also by overcoming obstructions to the free flow of the air. The fan therefore needs to have greater horsepower capacity (i.e. higher initial cost plus increased energy consumption during operation) in order to move the intended amount of air through the heat exchanger to overcome the increase in system pressure.
A further drawback of such an arrangement is that the ambient air first passes through the charge air cooler, and then passes through the jacket water cooler. The air enters the charge air cooler at ambient temperature (the maximum temperature differential). Heat energy is transferred from the charge air to the environmental air, such that the environmental air leaving the charge air cooler is warmer than the air entering the heat exchanger. The environmental air at an elevated temperature then enters the jacket water cooler where it again receives energy, this time transferred from the engine coolant. Yet, the air entering the jacket water cooler has a temperature above the ambient air temperature. Accordingly, the temperature differential between the coolant and the air is less than maximum, and the energy transfer is less than maximum. Such a design is disadvantageously engineered to be less than optimally efficient.
A still further drawback of the stacked system is that for dual turbocharged engines, a manifold is required to route the charge air through the charge air cooler. Several drawbacks can be associated with the use of a manifold. First, it would be undesirable if the return manifold did not evenly distribute the cooled charge air back to both sides of the engine. Second, the charge air can suffer from a pressure loss as it passes through the torturous paths of the manifold and other required piping. Pressure loss of the charge air during routing to and from the charge air cooler reduces the net effect of the turbochargers. Third, the piping and plumbing can add to the overall complexity of the design and manufacturing of the heat exchanger, and the piping and plumbing can be inconvenient to access.
It is well know that axial fans have a “dead” spot where the hub rotates due to the lack of air being driven. Non-uniform air flow rates in an axial direction are caused by the “dead” spots. The standard stacked arrangement prohibits mechanical compensation for different air flow rates across the front face of the heat exchanger due to the dead spot. Accordingly, some portions of the heat exchanger are capable at operating at higher efficiency relative the other portions making the overall heat transfer efficiency less than ideal. The zone of the dead spot and associated inefficiency is more profound downstream of the first heat exchanger where stacked arrangements are used.
Thus there exists a need for a heat exchanger that solves these and other problems.
The present invention is directed toward overcoming one or more of the disadvantages set forth above. The present invention relates to a heat exchanger, and particularly to a radiator with maximized entering temperature differentials for both at least one charge air cooler and a jacket water cooler.
According to one aspect of the present invention, a heat exchanger is provided for dissipating heat from a dual turbocharged engine. The heat exchanger can advantageously have a jacket water cooler, a first charge air cooler and a second charge air cooler. The three coolers can be arranged in parallel rather than in series (i.e. stacked arrangement), and each can have a front surface that lie, respectively, in parallel planes. The two charge air coolers are preferably located on opposite sides of the centrally located jacket water cooler. Charge air from the first turbocharger is piped to the first charge air cooler, and charge air from the second turbocharger is piped to the second charge air cooler. A first baffle is at least partially between the first charge air cooler and the jacket water cooler, and extends upstream there from. A second baffle is at least partially between the second charge air cooler and the jacket water cooler, and extends upstream there from. The baffles can direct selected amounts of air to each of the three coolers. The baffles also segregate the coolers to prevent radial convective scrubbing. A fuel oil cooler can also be provided.
According to one aspect of the present invention, a maximum entering temperature differential is provided for each cooler. This is accomplished by utilizing the relatively cool ambient air to enter each of the coolers, as opposed to having air first pass through a charge air cooler and then through a jacket water cooler.
According to another aspect of the present invention, the overall depth of the heat exchanger is decreased. Advantageously, the system resistance is decreased as a result of the side-by-side geometry of the jacket water cooler and the charge air coolers. Lowering the system resistance and pressure decreases parasitic energy loss via the fan or other components, and increases the efficiency of the heat exchanger. Accordingly, a fan with relatively less horsepower is required to move the necessary amount of air through the heat exchanger.
According to a further advantage, the plumbing to each of the charge air coolers is relatively uncomplicated, and comprises distinct cooling circuits. Pressure loss in the charge air circuits is advantageously decreased. All pressure loss in the charge air circuit decreases the net effect of the turbocharger. There is accordingly an incentive to minimize pressure losses in the charge air circuits. Also, the plumbing is more convenient to facilitate ease of assembly and service.
According to a still further advantage, selected amounts of axially moving air pushed from the fan can be directed to the jacket water cooler and each of the charge air coolers. This is accomplished with baffles that direct some of the ambient air to the area that conventionally is referred to as the “dead” spot. The baffles accordingly ensure proper flow through each of the coolers.
According to a still further advantage yet, the baffles segregate the coolers from each other. One component of the air flow of axial fans moves radially from the fan (the other component is the axially linear movement) and generally parallel to the front of the coolers. The baffles prevent the radial motion of the air from sweeping between coolers and transferring heat between the coolers and passing through the heat exchanger at the point of least resistance.
Other advantages, benefits, and features of the present invention will become apparent to those skilled in the art upon reading the detailed description of the invention and studying the drawings.
While the invention will be described in connection with several preferred embodiments, it will be understood that it is not intended to limit the invention to those embodiments. On the contrary, it is intended to cover all alternatives, modifications and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims.
The present invention is intended for use with an engine 10 designed for use with two turbochargers 20 and 25, respectively. Preferably, the engine 10 is a stationary engine. Yet, it is understood that the principals of the present invention could be applied to mobile engines. It is further understood that in a forced convection application, the mechanical air mover or fan may be unnecessary. The engine 10 has a coolant inlet 11 and a coolant outlet 12. The engine 10 further has a first charge air inlet 13 and a second charge air inlet 14. The charge air inlets 13 and 14 are preferably on opposed sides of the engine 10. A fuel inlet 15 is further provided, as well as an excess fuel outlet 16.
Two turbochargers 20 and 25 are used with the engine 10. Turbocharges 20 and 25 each comprise two chambers. The chambers house a turbine and a compressor, respectively. It is typical for a common shaft to connect the turbine blades and the compressor blades. Exhaust from the engine flowing out of exhaust enters the turbine and expands through the turbine blades. The expansion through the turbine blades cause the blades and shaft to rotate at a high rate of speed. The rotation of the shaft causes the blades in the compressor to likewise rotate. The compressor blades pull ambient air into the compressor to compress the air to relatively high temperature and pressure.
An air mover is provided. One preferred air mover is a fan 30. The fan 30 has a hub 31 and blades 32. The fan 30 has a central axial axis. The blades 32 can be formed with a selected pitch to achieve an intended linear axial flow of ambient air at the ambient air temperature. A schematic diagram of the air flow is shown in
A heat exchanger 35 is provided for dissipating heat from the engine 10, and cooling the charged air from the turbochargers 20 and 25. The heat exchanger 35 has a frame 36. Some other primary components include a jacket water cooler 40, a first charge air cooler 60, a second charge air cooler 80, a fuel oil cooler 100, a first baffle 120 and a second baffle 130. A detailed description of each of these components follows. The heat exchanger has a first side bracket 140 with a face 141, and a second side bracket 150 with face 151. The first and second brackets 140 and 150 define the outside side walls of the heat exchanger. The front of the heat exchanger 35 is upstream, and the rear of the heat exchanger is downstream.
Looking now at
A coolant inlet 50 is provided, as is a coolant outlet 51. The inlet is preferably located at or near the top 45 of the jacket water cooler 40. The outlet 51 is preferably located at or near the bottom of the jacket water cooler 40. An inlet line 52 is provided. The inlet line 52 has a first end connected to the coolant outlet 12 of the engine, and a second end connected to the coolant inlet 50 of the jacket water cooler. An outlet line 53 is also provided. The outlet line 53 has a first end connected to the coolant inlet 11 of the engine 10, and a second end connected to the coolant outlet 51 of the jacket water cooler 40. It is appreciated that, as shown in
A first charge air cooler 60 is provided for dissipating heat from the charge air from the first turbocharger 20. This cooler 60 is preferably an air to air heat exchanger. It can be constructed of metal oval tubes and metal serpentine fins. The tubes can be aligned in a parallel pattern and can be multiple rows deeps. Air can flow into and out of the cooler 60 through aluminum nozzles. It is understood that while the description heretofore represents preferred construction, other embodiments can be used without departing from the broad aspects of the present invention. The first charge air cooler 60 is preferably held in place by the frame 36 of the heat exchanger 35. The first charge air cooler 60 has a top 61, a bottom 62, a first side 63, a second side 64 and a front 65. The front 65 of the first charge air cooler 60 preferably is planar and lies in plane 66. The front 65 is preferably upstream of a back 67.
A charge air inlet 70 is provided, as is a charge air outlet 71. The inlet is preferably located at or near the top 61 of the first charge air cooler 60. The outlet 71 is preferably located at or near the bottom of the first charge air cooler 60. An inlet line 72 is provided. The inlet line 72 has a first end connected to the first turbocharger 20 for receiving charge air, and a second end connected to the charge air inlet 70 of the first charge air cooler. An outlet line 73 is also provided. The outlet line 73 has a first end connected to the first charge air inlet 13 of the engine 10, and a second end connected to the charge air outlet 71 of the first charge air cooler 60. It is appreciated that, as shown in
The first charge air cooler 60 is preferably located near the jacket water cooler 40 in a parallel arrangement. Stated another way, the first charge air cooler 60 and the jacket water cooler 40 are neither upstream nor downstream of each other. This is accomplished as side 64 of the first charge air cooler 60 is near the side 43 of the jacket water cooler 40. The front surface 45 of the jacket water cooler 40 is also preferably parallel to the front surface 65 of the first charge air cooler 60, such that both are preferably perpendicular to the axial flow of ambient air driven by the fan.
A second charge air cooler 80 is provided for dissipating heat from the charge air from the second turbocharger 25. This cooler 80 is preferably an air to air heat exchanger. It can be constructed of metal oval tubes and metal serpentine fins. The tubes can be aligned in a parallel pattern and can be multiple rows deeps. Air can flow into and out of the cooler 80 through aluminum nozzles. It is understood that while the description heretofore represents preferred construction, other embodiments can be used without departing from the broad aspects of the present invention. The second charge air cooler 80 is preferably held in place by the frame 36 of the heat exchanger 35. The second charge air cooler 80 has a top 81, a bottom 82, a first side 83, a second side 84 and a front 85. The front 85 of the second charge air cooler 80 preferably is planar and lies in plane 86. The front 85 is preferably upstream of a back 87.
A charge air inlet 90 is provided, as is a charge air outlet 91. The inlet is preferably located at or near the top 81 of the second charge air cooler 80. The outlet 91 is preferably located at or near the bottom of the second charge air cooler 80. An inlet line 92 is provided. The inlet line 92 has a first end connected to the second turbocharger 25 for receiving charge air, and a second end connected to the charge air inlet 90 of the second charge air cooler. An outlet line 93 is also provided. The outlet line 93 has a first end connected to the second charge air inlet 14 of the engine 10, and a second end connected to the charge air outlet 91 of the second charge air cooler 80. It is appreciated that, as shown in
The second charge air cooler 80 is preferably located near the jacket water cooler 40 in a parallel arrangement. The second charge air cooler 80 is preferably on an opposed side of the jacket water cooler 40 from the first charge air cooler 60. The first charge air cooler 60, the second charge air cooler 80 and the jacket water cooler 40 are neither upstream nor downstream of each other. This is accomplished as side 83 of the second charge air cooler 80 is near the side 44 of the jacket water cooler 40. The front surface 45 of the jacket water cooler 40 is also preferably parallel to the front surface 85 of the second charge air cooler 80, such that both are preferably perpendicular to the axial flow of ambient air driven by the fan.
A fuel oil cooler 100 is provided for dissipating heat from the excess fuel from the engine 10. This cooler 100 is preferably a liquid to air heat exchanger. It can be constructed of metal round tubes and metal flat fins. Fuel can flow into and out of the cooler 100 through metal nozzles. It is understood that while the description heretofore represents preferred construction, other embodiments can be used without departing from the broad aspects of the present invention. The fuel oil cooler 100 is preferably held in place by brackets that are supported by the frame 36 of the heat exchanger 35, as best shown in
An inlet 110 is provided by the fuel oil cooler 100, as is an outlet 111. An inlet line 112 is provided. The inlet line 112 has a first end connected to the excess fuel outlet 16 of the engine 10, and a second end connected to the fuel oil cooler inlet 110. An outlet line 113 is also provided. The outlet line 113 has a first end connected to a fuel reservoir, and a second end connected to the outlet 111 of the fuel oil cooler 100. It is appreciated that, as shown in
In the illustrated embodiment, the fuel oil cooler 100 is stacked upstream of the second charge air cooler 80. The surface area of the front 105 of the fuel oil cooler is much smaller that the surface area of the second charge air cooler 80, as shown in FIG. 3A. The front 105 of the fuel oil cooler is preferably parallel to the front 85 of the second charge air cooler 80.
Turning attention now to
The partition 123 can be partially between the first charge air cooler 60 and the jacket water cooler 40. The face 124 extends upstream from between the coolers 60 and 40. The face 124 is preferably angled towards the bracket 140 and the outside of the heat exchanger such that it is upstream of the first charge air cooler. The face 124 divides the ambient air driven by the fan and directs selected amounts of air to pass through each of the jacket water cooler 40 and the first charge air cooler 60. In this regard, the air entering at the ambient air temperature independently passes through the jacket water cooler 40 and the fist charge air cooler 60. The face 124 also prevents radial convective scrubbing, or air that is swept radially from scrubbing across one of the coolers 60 or 40 and heating the other cooler, such as from cooler 60 to cooler 40.
A second baffle 130 is also provided according to the present invention. Baffle 130 is preferably made of metal. The baffle 130 has a top 131 and a bottom 132. The baffle comprises a first segment, or partition 133, and a second segment, or face 134. The face 134 has a leading edge 135. The leading edge is concave and has an arch 136 or curve. The baffle partition segment 133 and face segment 134 can be rigidly connected or adjustably connected. It is understood that other shapes could be used without departing from the broad aspects of the present invention.
The partition 133 is at least partially between the second charge air cooler 80 and the jacket water cooler 40. The face 134 extends upstream from between the coolers 80 and 40. The face 134 is preferably angled towards the bracket 150 and the outside of the heat exchanger such that it is upstream of the second charge air cooler. The face 134 divides the ambient air driven by the fan and directs selected amounts of air to pass through each of the jacket water cooler 40 and the second charge air cooler 80. In this regard, the air entering at the ambient air temperature independently passes through the jacket water cooler 40 and the second charge air cooler 80. It is understood that a portion of the air passes through the fuel oil cooler 100 before passing through the second charge air cooler 80. The face 134 also prevents radial convective scrubbing, or air that is swept radially from scrubbing across one of the coolers 80 or 40 and heating the other cooler, such as cooler 80 to cooler 40.
Turning attention now to
The partition 223 can be partially between the first charge air cooler and the jacket water cooler. The face 224 extends upstream from between the jacket water cooler and the first charge air cooler. The face 224 is preferably angled towards the bracket and the outside of the heat exchanger such that it is upstream of the first charge air cooler. The face 224 divides the ambient air driven by the fan and directs selected amounts of air to pass through each of the jacket water cooler and the first charge air cooler. In this regard, the fan causes air entering at the ambient air temperature to independently pass through the jacket water cooler and the fist charge air cooler. The face 224 also prevents radial convective scrubbing, or air that is swept radially from scrubbing across one of the coolers and heating the other cooler.
It is understood that a second similar shaped baffle (not shown) could be used between and upstream of the second charge air cooler and the jacket water cooler.
Looking now at
The system resistance normally associated with fully stacked systems is decreased by the present invention, as the air passes through only one cooler. Accordingly, the driving potential of the air mover is increased. Further, the baffles ensure that selected amounts of air pass through each cooler and prevent all the driven air from passing through the cooler with the least resistance.
It is noteworthy that the first charge air circuit 74 is direct to the first charge air cooler 60 and then to the first engine intake 13, and the second charge air circuit 94 is direct to the second charge air cooler 80 and to the second engine intake 14. The separate internal cooling circuits allows for the heat exchanger to operate without complex installation and manifolding.
Thus it is apparent that there has been provided, in accordance with the invention, a radiator that fully satisfies the objects, aims and advantages as set forth above. While the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, it is intended to embrace all such alternatives, modifications, and variations as fall within the spirit and broad scope of the appended claims.
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|---|---|---|---|
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| 5215044 | Banzhaf et al. | Jun 1993 | A |
| 5353757 | Susa et al. | Oct 1994 | A |
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| 20020088230 | Coleman et al. | Jul 2002 | A1 |
