Patent Application
20160123683
The disclosed inventive concept relates generally to charge air coolers for automotive vehicles. More particularly, the disclosed inventive concept relates to a resonant charge air cooler core having internal structures to create turbulence and thereby enhance heat transfer.
It is increasingly common for internal combustion engines to be fitted with turbochargers or superchargers to force more air mass into the engine's intake manifold and combustion chamber. The increased amount of air mass is the result of the air being compressed by an air compressor driven by a turbine which is itself driven by an impeller associated with the exhaust system. While improving engine horsepower, the input of compressed air heats the intake manifold, thus causing a reduction in the density of the charge air.
To offset the increased temperature of the incoming air, charge air coolers have been provided upstream of the airflow. The typical charge air cooler (CAC) includes an air inlet tank, an air outlet tank, and a series of elongated and parallel cooling tubes fluidly connecting the air inlet tank to the air outlet tank.
While the technology for efficient charge air coolers continues to advance, the designers of these coolers are challenged by constraints on packaging. It is known that to achieve a high charge air cooler efficiency, charge air coolers should have a surface area that is large enough to provide sufficient surface area that proper cooling of the air flowing from the inlet tank to the outlet tank can take place. However, the size of the charge air cooler is very often restricted by the available space.
Restriction of available space is created by a number of factors. First, for maximum cooling efficiency, charge air coolers should receive “first air,” that is, they should be positioned in front of the radiator and other heat exchangers. Second, known components such as the active radar adjustment screw and the active grill shutter housing result in a very confined space for the charge air cooler. The minimal space available for the charge air cooler is in conflict with the need to provide a charge air cooler that is as large as possible.
Accordingly, as in so many areas of vehicle technology, there is room for improvement in the design of charge air coolers whereby maximum cooling can be achieved using a cooler that is of a smaller size, thereby being suitably sized for the confined areas known in today's vehicle.
The disclosed inventive concept overcomes the problems associated with known charge air coolers by providing maximum air cooling in a cooler being of a relatively small size. This result is generally achieved by providing structures internal to the charge air cooler that produce vortexes in the air flow, thus inducing turbulence and increasing heat transfer efficiency.
Recognizing that during different working conditions of the vehicle the flow may be laminar, transitional or turbulent, the flow is confirmed as being turbulent in most working conditions by providing a selected internal structure. The structures may be one of (or a combination of) a wire mesh, a wire grid or a frame having parallel wires provided in the inlet tank. By changing the geometry of the internal structure, turbulent eddies are created at very small length scales. The size of the eddies and the quality of the turbulence may be determined by the geometry of the internal structure.
By adjusting the geometry of the turbulence-inducing internal structure, turbulent eddies can be formed at very small length scales. The size of the eddies and quality of the turbulence may thus be determined by the geometry of the turbulence-inducing internal structure. Furthermore, by adding grooves or dimples on an interior surface of the charge air cooler, heat transfer is increased as a result of the vortexes produced and the intensified mixing. When the time scale of the fluid unsteadiness (that is, the turbulence eddies) and the time scale of grooves or dimples (the time required for the flow to pass the groove surface) coincide, the heat transfer conductance coefficient increases significantly. This behavior is similar to a resonance in structural or vibrational mechanics.
In order to make use of this resonant effect in the disclosed inventive concept, the resonant charge air cooler disclosed herein includes either a long wire squeezed into the inlet tank or, alternatively, a wire mesh screen provided at the inlet window of the tube. The geometry of such structures may be adjusted to impose vortexes that have almost the same size as those produced by the surface dimples or grooves formed on the walls of the tubes that connect the inlet and outlet tanks, whereby a resonance behavior occurs and heat transfer increases considerably. An increase in heat transfer allows for the reduction of the size of the charge air cooler without compromising cooling efficiency.
The above advantages and other advantages and features will be readily apparent from the following detailed description of the preferred embodiments when taken in connection with the accompanying drawings.
For a more complete understanding of this invention, reference should now be made to the embodiments illustrated in greater detail in the accompanying drawings and described below by way of examples of the invention wherein:
In the following figures, the same reference numerals will be used to refer to the same components. In the following description, various operating parameters and components are described for different constructed embodiments. These specific parameters and components are included as examples and are not meant to be limiting.
The resonant charge air cooler of the disclosed inventive concept is illustrated in its various embodiments in
Referring to
Perpendicular to and extending from the inlet tank body 16 and fluidly connected thereto are a plurality of coolant tubes 18. The number, shape and placement of the tubes 18 may be other than as illustrated.
The resonant charge air cooler 10 further includes an outlet tank 20 having an outlet 22 and an outlet tank body 24. Like the inlet tank 12, the outlet tank 20 may be made from any one of several materials, including a polymerized material or a metal or a combination of the two.
Brackets are preferably attached to the resonant charge air cooler 10 for fixing the resonant charge air cooler 10 to the heat exchanger (not shown), to a structure in the vehicle's engine compartment, or to both. A first set of brackets 26 and 26′ and a second set of brackets 28 and 28′ are preferably provided. The shape, placement and number of brackets may be varied beyond the illustrated brackets 26, 26′, 28 and 28′.
To create the appropriate vortex in the coolant tubes 18, the inner surfaces of the tubes 18 have structures formed thereon. The inner surfaces may be dimpled or grooved or may have another vortex-inducing structure formed thereon.
Referring to
Vortex-initiating alternatives for the interior surface 30 of the tube 18 other than the raised dimples 32 shown in
While the raised dimples 32 and the grooves 34 are provided to create vortices within the tube 18, an additional vortex-initiating structure is provided in relation to the inflowing air. Particularly, and referring to
The geometries of the raised dimples 32 and/or grooves 34 as well as the geometries of the randomly-arranged wires 36 may be modified in the resonant charge air cooler 10 to achieve maximum cooling within a minimal space. For example, the size, number and spacing of the raised dimples 32 and the number, depth and placement of the grooves 34 may be modified. In addition, the thickness, number, length and spacing of the randomly-arranged wires 36 may be modified. By adjusting these geometries, an optimum resonance behavior may be generated within the resonant charge air cooler 10 to thereby maximize heat transfer.
While
Referring to
Perpendicular to and extending from the inlet tank body 46 and fluidly connected thereto are a plurality of coolant tubes 48. The number, shape and placement of the tubes 18 may be other than as illustrated. Like the coolant tubes 18 shown in
The resonant charge air cooler 40 further includes an outlet tank 50 having an outlet tank body 52 and an outlet 54. Like the inlet tank 42, the outlet tank 50 may be made from any one of several materials, including a polymerized material or a metal or a combination of the two.
Brackets are preferably attached to the resonant charge air cooler 40 for fixing the resonant charge air cooler 40 to the heat exchanger (not shown), to a structure in the vehicle's engine compartment, or to both. A first set of brackets 56 and 56′ and a second set of brackets 58 and 58′ are preferably provided. The shape, placement and number of brackets may be varied beyond the illustrated brackets 56, 56′, 58 and 58′.
To induce the appropriate vortex within the inlet tank 42, a wire grid 60 is fitted to an inner wall 62 of the inlet tank 42 to which the tubes 48 are fluidly connected. An exemplary version of the wire grid 60 is shown in
As with the first embodiment of the resonant charge air cooler of the disclosed inventive concept illustrated in
Structures alternative to the wire grid 60 may be used in conjunction with the resonant charge air cooler of the disclosed inventive concept illustrated in
As a variation of the turbulence-inducing structure 70 shown in
The thicknesses of the wires 74 and 84 and the spacing between the wires 74 and 84 may be varied from the illustrations of
The resonant charge air cooler of the disclosed inventive concept in its various embodiment overcomes the problems of known systems by providing maximum heat exchange in a minimum amount of space. It is to be understood that the resonant system disclosed herein has been discussed in relation to charge air coolers, the use of vortex-inducing structures in relation to the inlet tank and the tubes may be applied as well to other heat exchangers, including without limitation condensors, transmission coolers, and radiators.
While the preferred embodiments of the disclosed inventive concept have been discussed are shown in the accompanying drawings and are set forth in the associated description, one skilled in the art will readily recognize from such discussion, and from the accompanying drawings and claims that various changes, modifications and variations can be made therein without departing from the true spirit and fair scope of the invention as defined by the following claims.
