Abstract:
A drag reducing system is disclosed for reducing drag on a motor vehicle. For some embodiments, the drag reducing apparatus comprises one or more dimpled panels each comprising a sheet with dimples distributed on the surface of the sheet. For such embodiments, the one or more dimpled panels are coupled to one or more sides of the motor vehicle. Furthermore, the one or more dimpled panels are positioned in a contiguous manner on the one or more sides of the motor vehicle.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority to, and the benefit of, U.S. Provisional Patent Application entitled, “A Method of Reducing Form Drag on Vehicles and Trailers Through the use of a Dimpled Surface,” having Ser. No. 61/069,522, filed on Mar. 14, 2008, which is incorporated by reference in its entirety. 
     
    
     TECHNICAL FIELD 
       [0002]    The present disclosure generally relates to reducing drag on motor vehicles, and particularly, to reducing form drag on motor vehicles through the use of a dimpled surface. 
       BACKGROUND 
       [0003]    It is generally known that form drag arises based on the form of a given object. In particular, the general size and shape of the object affect the amount of drag that a moving object such as a motor vehicle experiences. Objects with a larger apparent cross-section will have a higher drag than thinner bodies. As such, a significant amount of aerodynamic drag is created when a large vehicle such as a tractor-trailer travels along a highway. The amount of form drag experienced by a moving vehicle directly impacts the fuel consumption of the vehicle, thereby increasing costs associated with operating the vehicle. When transporting goods across a long distance, for example, an increase in fuel efficiency can lead to a significant savings in fuel costs. 
       SUMMARY 
       [0004]    Briefly described, one embodiment, among others, includes a drag reducing system for reducing drag on a motor vehicle. For some embodiments, the drag reducing apparatus comprises one or more dimpled panels each comprising a sheet with dimples distributed on the surface of the sheet. For such embodiments, the one or more dimpled panels are coupled to one or more sides of the motor vehicle. Furthermore, the one or more dimpled panels are positioned in a contiguous manner on the one or more sides of the motor vehicle. 
         [0005]    Another embodiment is a drag reducing assembly for reducing form drag of a moving motor vehicle. The drag reducing assembly comprises a flexible sheet with a thickness about 0.2 centimeter to about 10 centimeters. The assembly further comprises a plurality of round dimples distributed on the flexible sheet such that the flexible sheet comprises a dimpled surface. In accordance with such embodiments, the flexible sheet is detachably coupled to a motor vehicle, wherein the flexible sheet is coupled to the motor vehicle such that the side of the flexible sheet with cavities formed by the dimples on the flexible sheet is facing outward away from the surface of the motor vehicle. 
         [0006]    Another embodiment is a motor vehicle body that comprises a plurality of dimpled sides each comprising bumps distributed on the surfaces of the dimpled sides, wherein the bumps each have a height of approximately 0.2 to 10 centimeters. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    Various aspects of the disclosure can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale, with emphasis instead being placed upon clearly illustrating the principles of the present disclosure. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views. 
           [0008]      FIG. 1  depicts a motor vehicle on which the various embodiments described may be implemented. 
           [0009]      FIGS. 2A-B  illustrate the form drag experienced by the motor vehicle in  FIG. 1  with and without a dimpled surface in accordance with some embodiments 
           [0010]      FIG. 3  shows one of the dimpled panels attached to the motor vehicle shown in  FIGS. 1-2 . 
           [0011]      FIG. 4  depicts various shapes in which the dimples shown in the dimpled panels of  FIG. 3  may be formed. 
           [0012]      FIGS. 5-7  depict perspective views and side views of various embodiments of the dimpled panels. 
       
    
    
     DETAILED DESCRIPTION 
       [0013]    Having summarized various aspects of the present disclosure, reference will now be made in detail to the description of the disclosure as illustrated in the drawings. As described in the background, a significant amount of aerodynamic drag is created when a large vehicle such as a tractor-trailer travels along a highway. The amount of form drag experienced by a moving vehicle directly impacts the fuel consumption of the vehicle, thereby increasing costs associated with operating the vehicle. As such, when transporting goods cross-country in a tractor-trailer, an increase in fuel efficiency can lead to a significant savings in fuel costs. Various embodiments thus are described for implementing one or more dimpled surfaces for reducing the form drag on a motor vehicle when the motor vehicle is moving. In particular, a plurality of dimples is distributed on one or more sheets which are attached to the surface of a trailer attached to a motor vehicle. 
         [0014]    In alternative embodiments, bumps or protuberances, rather than dimples, may be used to achieve similar results. Furthermore, the dimples or bumps may be incorporated directly onto the surface of the trailer. While application of the various embodiments described is not limited to a particular range of speeds, a substantial reduction in form drag may be observed when the motor vehicle is moving approximately 45 mpg to 75 mph. One of ordinary skill in the art will appreciate that a reduction in form drag exerted on a vehicle or trailer results in less energy being required to move the vehicle or trailer, thereby improving the fuel efficiency for the vehicle. As will be described later in this disclosure, the various embodiments may be implemented in an inexpensive manner and may be readily attached and fitted to any vehicle. 
         [0015]    Reference is made to  FIG. 1 , which depicts a motor vehicle  100  on which the various embodiments described may be implemented. The motor vehicle  100  may comprise, for example, a truck used for commercial transportation of goods and may comprise a tractor unit  102  and a trailer  104  used for storing and transporting goods. It is commonly known that some trailers  104  are utilized for personal use with practically any powered vehicle such as a pick-up truck having an appropriate hitch, while larger trailers  104  are part of large trucks called semi-trailer trucks for transportation of cargo. 
         [0016]    Reference is now made to  FIGS. 2A-B , which illustrate the form drag experienced by a motor vehicle  100  with and without a dimpled surface. As known by those of ordinary skill in the art, drag or “form drag” is generated based on the form of the object. The general size and shape of a particular body (e.g., a trailer  104 ) is the primary factor in form drag. Bodies with a larger apparent cross-section will have a higher drag than thinner bodies. Aerodynamic designs or designs that are streamlined with a varying cross-sectional area also affect form drag. Form drag follows the drag equation in that it rises with the square of speed, and thus becomes more important a high speeds. Shown in  FIG. 2A  is a motor vehicle  100  such as the one depicted in  FIG. 1  with no modifications. The form drag experienced by the motor vehicle  100  is also shown.  FIG. 2B  depicts a motor vehicle  100  with a dimpled surface. As will be described later, panels  202  with dimpled surfaces may be attached to the surface of the motor vehicle  100  to reduce form drag. 
         [0017]      FIG. 3  shows one of the dimpled panels  202  attached to the motor vehicle  100  in  FIG. 2 . In accordance with some embodiments, dimples  304  are embedded into flexible sheets  302  which are readily attached to the surface of a vehicle  100 . The sheets  302  may be constructed from a variety of materials, including, but not limited to, rubber and plastic. Further, the dimpled sheets  202  may be attached to the surface of a vehicle in variety ways, such as with an adhesive or with mechanical fasteners. For other embodiments, the dimpled sheets  202  may be magnetic. The sheets  302  may be constructed in a variety of shapes, including but not limited to, a polygonal shape such as a square, rectangle, triangle, hexagon, etc. In other embodiments, the sheets  302  may comprise a non-polygonal shape such as, but not limited to, a circle, an oval, a decorative shape, an amorphous shape, among other shapes. 
         [0018]    The dimples  304  depicted in  FIG. 3  may be concave with respect to the sheets  302  such that an indentation is formed in the sheets. Alternatively, the dimples  304  may be cut perpendicularly to the surface of the sheet  302  such that through holes are formed in the sheet  302 . By way of illustration, the holes on a peg board are cut in a similar manner. The dimples  304  may be cut entirely through the sheets, or they  304  may be cut partially through the sheets  302 . Regarding the distribution of the dimples  304  on the sheet  302 , the dimples  304  may be spaced randomly, increasingly apart, decreasingly apart, etc. Furthermore, the dimples  304  may be spaced based on a variety of distances. For example, the dimples  304  may be spaced starting from a fraction of a centimeter apart and gradually to a few centimeters apart. With reference to  FIG. 4 , the dimples may be implemented in any number of shapes. Referring back to the motor vehicle in  FIG. 2B , the dimpled sheets  202  are preferably installed next to each other on the surface of the motor vehicle  100 . To minimize the weight by the dimpled sheets  202 , the dimpled sheets  202  are preferably constructed to be less than a few centimeters thick.  FIGS. 5-7  depict perspective views and side views of various embodiments of the dimpled panels. 
         [0019]    Having described the basic structure of the dimpled sheets  202 , the effect on form drag of a motor vehicle is now described in more detail. Incorporating a dimpled surface on a moving vehicle increases the fuel efficiency of a vehicle as the dimples reduce the form drag of a vehicle or a vehicle&#39;s trailer. As one of ordinary skill will appreciate, a dimpled surface changes the airflow from a laminar flow to a turbulent flow, and turbulent flow has more energy than laminar flow. As such, the flow stays attached (i.e., the air experiences adhesion) longer on the surface with turbulent flow than on the surface with laminar flow. 
         [0020]    Referring back briefly to  FIGS. 2A-B ,  FIG. 2A  shows the laminar flow over a heavy-duty tractor-trailer  100  that does not have a dimpled surface.  FIG. 2B  shows the turbulent flow over a heavy-duty tractor-trailer  100  with a dimpled surface  202 . As shown, the turbulent flow delays the separation of the flow behind the vehicle or behind the trailer  100 . The result of this delay in separation of the air flow is a decrease in the form drag, also called pressure drag, exerted on the vehicle  100  or the trailer  104 . With less drag on the vehicle  100  or trailer  104 , less energy is needed to move the vehicle or trailer forward. This ultimately leads to increased fuel efficiency of the engine that moves the vehicle  100  or trailer  104 . 
         [0021]    It should be noted that for other embodiments, bumps or protuberances, rather than dimples, may be used to achieve similar results. In particular, the sheets  302  may contain bumps on them instead of dimples. Alternatively, bumps may be attached directly onto the side of a vehicle  100  or trailer  104 . It should further be noted that the various embodiments described may be implemented on watercraft, aircraft, and other objects (recreational objects, unmanned objects, etc.). For embodiments where a dimpled surface is implemented directly onto the surface of a motor vehicle  100 , the dimpled surface can be implemented at the time of manufacture of the vehicle or trailer. For instance, when the trailer of a heavy-duty tractor-trailer is being manufactured, a group of dimples can be applied to the surface of the trailer. Alternatively, when the trailer of a heavy-duty tractor-trailer is being manufactured, a group of dimples can be applied to the surface of an object or objects, such as sheets of plastic, and these objects can then be applied to the surface of the trailer. 
         [0022]    It should be emphasized that the above-described embodiments are merely examples of possible implementations. Many variations and modifications may be made to the above-described embodiments without departing from the principles of the present disclosure. All such modifications and variations are intended to be included herein within the scope of this disclosure and protected by the following claims.