Abstract:
A cowling assembly ( 10 ) is installed about the radiator (R) of a vehicle (V). A frame ( 12 ) fits about the radiator and defines an opening through which air can flow into the radiator. The frame has a contour that allows air flow smoothly about the frame. A cover including a panel ( 18 ) or a coiled sheet ( 118 ) is movable through the frame to cover the opening. A motor ( 50 ) operated by a controller ( 80 ) moves the panels or sheets to expose a portion of the opening and allow air to flow into the radiator. The frame and the panel or sheet facilitate smoother air flow over and about the front of the vehicle thereby reducing the amount of drag on it while still allowing air flow into the radiator.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    Provisional U.S. patent application 61/567,158 filed Dec. 6, 2011 
     
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0002]    N/A 
       BACKGROUND OF THE INVENTION 
       [0003]    This invention relates to reducing drag in over-the-road vehicles (including trucks and passenger car) to make them more fuel efficient; and, more particularly, to a cowling, shroud, or fairing (collectively, a cowling) which is installed over the radiator of the vehicle to improve the vehicle&#39;s aerodynamic characteristics. 
         [0004]    It is well known that over the road trucks, semis and the like, have low fuel efficiency. Typically, these tractor trailer vehicles attain about five to seven miles per gallon (5-7 mpg) when traveling at highway speeds of, for example, 50-70 miles per hour (mph). One reason for this is the aerodynamic characteristics of these vehicles and their high coefficient of drag. A number of attempts have been made to improve the aerodynamics of these vehicles in order to improve gas mileage. Fairings with curved surfaces have been mounted on top the vehicle&#39;s cab to create a smoother air flow over the top of the vehicle. Other devices have also been installed on the vehicles for this purpose. 
         [0005]    However, a major contributor to the vehicle&#39;s drag is the blunt front end of the truck where the radiator is located. The radiator, which is generally rectangular in shape, extends vertically from an area adjacent the truck&#39;s from bumper to the top of its hood. It also extends horizontally across a good portion of the front end of the track. As the truck moves over the road, air strikes the radiator and is forced either over or under the top and bottom of the radiator, and about it sides. This, in turn, creates a drag which significantly impacts the trucks forward movement and increases its fuel consumption. 
         [0006]    With regard to the above described problem, it is known to use spoilers or air dams to help reduce drag. However, these are typically static devices which provide a limited amount of help in reducing drag. Further, these devices are specific to the particular vehicle on which they are installed. It would be valuable and advantageous to have a structure (cowling, fairing, shroud, air dam or the like) as either original equipment (OE) or as a retrofit which is adjustable so to reduce the drag encountered in a variety of situations and in which, even if only one particular design is usable on a particular vehicle, its operation can be adjusted to accommodate any differences between vehicles of the same type. 
         [0007]    While passenger cars and similar vehicles do not create the same amount of drag as trucks when they travel at highway speeds, use of a cowling of the present invention on them will also improve their fuel efficiency. 
       BRIEF SUMMARY OF THE INVENTION 
       [0008]    The present invention is directed to a cowling which is installed over a truck&#39;s radiator either as original equipment, or as a retrofit. The cowling, when installed, has a curved outer surface which promotes aerodynamic airflow over, under, and about the sides of the cowling so to significantly reduce drag and improve fuel efficiency. 
         [0009]    The cowling includes a frame installed about the sides of the radiator. Sheets, coils, or panels, or a combination of these elements and their associated structure, are either mounted in the frame, or are incorporated in the grill or hood of the vehicle. Regardless of which construction is used, the resulting size and shape produces an aerodynamic configuration which reduces drag and promotes improved vehicle fuel economy. Electric motors such as stepper or gear motors are used to move the various components either vertically or horizontally with respect to the radiator, depending upon the radiator design, so to expose the radiator to air. This allows airflow through the radiator (and about the engine) so to draw heat away from it; while, at the same time, improving the drag characteristics of the vehicle and increasing its fuel efficiency. 
         [0010]    The cowling further includes heat flow paths by which a heated fluid from the radiator flows through the cowling so to prevent it from freezing up during cold, sleet, ice and snow conditions. In other embodiments of the invention, a heating system is employed with the elements, or tracks in which they move, so to create sufficient heat to prevent freeze up of the system in icy or freezing conditions. Alternately, these components are coated with a thermal film for the same purpose. 
         [0011]    Movement of the sheets, coils, or panels is controlled by a controller programmed for the vehicle on which the cowling is installed. The controller, which is either stand-alone or is incorporated into an electronic control module (ECM) of the vehicle, receives as inputs the outputs of sensors monitoring the temperature of the various engine fluids, radiator fluid temperature, the ambient temperature of outside air, and other parameters, so to control the opening and degree of opening of the sheets, coils, or panels. 
         [0012]    The cowling assembly is relatively lightweight and the parts are made of a rugged, molded plastic material or a shaped metal. The cowling is easy to install, remove, and service. The cowling is relatively low cost and has a useful life of 6-9 years. When in use, the cowling restores a significant amount of horsepower otherwise wasted by vehicles as currently configured and realizes substantial (e.g., an estimated $1.5B-4.0B) annual fuel savings because of the reduction in drag affected by the cowling if, for example, the entire current fleet of trucks were outfitted. 
         [0013]    Various embodiments of the invention, as noted, employ coiled sheets of material, panels, and combinations thereof. Also as noted, the sheets or panels, is oriented either to move across the front of the radiator from side-to-side, or up and down. In this latter embodiment, a coiled sheet is drawn down from the top of the hood of the vehicle; or, alternately, up from the vehicle&#39;s front bumper. In still another embodiment, the track over which the panels or sheet moves is integrally formed with the hood of the vehicle. In a further embodiment, the panel or sheets slide under the front bumper of the vehicle; or, they duct up into the radiator assembly. 
         [0014]    Alternately, the invention employs an adjustable structure for reducing the amount of air flowing underneath a vehicle so to reduce aerodynamic lift and drag. The structures installed on similar type vehicles are adjustable to take into account any differences between the vehicles. 
         [0015]    Those skilled in the art will appreciate that variations of the cowling installed on passenger cars will achieve similar advantageous results for these vehicles. 
         [0016]    Other objects and features will be in part apparent and in part pointed out hereinafter. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0017]    The objects of the invention are achieved as set forth in the illustrative embodiments shown in the drawings which form a part of the specification. 
           [0018]      FIG. 1  is a simplified representation of an over-the-vehicle illustrating current structures used to improve the aerodynamics of the vehicle; 
           [0019]      FIGS. 2A-2D  are respective perspective, front, top, and side views of a first embodiment of the invention in which panels move vertically; 
           [0020]      FIG. 3A  is an exploded view illustrating one embodiment of a cowling assembly of the present invention for installation with the hood of a truck,  FIG. 3B  is an installed view of the cowling assembly of  FIG. 3A  in a partially open position, and  FIG. 3C  illustrates a fully open position of the cowling assembly; 
           [0021]      FIG. 4A  is a perspective view of the cowling assembly in a substantially closed position,  FIG. 4B  is a side view of the cowling assembly in its  FIG. 4A  position and  FIG. 4C  is a sectional view of the assembly in this position, and  FIG. 4D  is a view similar to  FIG. 4A  with the cowling assembly in a more open position; 
           [0022]      FIGS. 5A-5E  illustrate a second embodiment of the invention employing tracks over which a panel is moved; 
           [0023]      FIGS. 6A-6C  illustrate various degrees of opening of a radiator to air flow by operation of the second embodiment; 
           [0024]      FIGS. 7A and 7B  are respective perspective and elevation views of a track used in the second embodiment of the cowling assembly; 
           [0025]      FIGS. 8A and 8C  illustrate a drive mechanism for use with the first embodiment of the cowling assembly; 
           [0026]      FIGS. 9A-9C  illustrate a drive mechanism for use with the second embodiment of the assembly; 
           [0027]      FIGS. 10A-10C  illustrate another embodiment of the drive mechanism for use with the second embodiment of the invention; 
           [0028]      FIGS. 11A and 11B  illustrate still another embodiment of the drive mechanism for use with the second embodiment of the invention; 
           [0029]      FIGS. 12-14  are sectional views of the cowling assembly illustrating different mechanical connections with a panel to move the panel over the radiator; 
           [0030]      FIGS. 15A-15C  are block diagrams of control systems for operating the panel drive mechanism; 
           [0031]      FIG. 16  is a perspective view, partly broken away of a panel used in the cowling assembly; 
           [0032]      FIG. 17  illustrates a plurality of interconnected panels; 
           [0033]      FIG. 18A  is a perspective view illustrating how the panels are connected together and  FIG. 18B  is side view of the interconnected panels; 
           [0034]      FIG. 19A  is an elevation view of a shear pin used to interconnect the panels and  FIG. 19B  is a sectional view of the pin taken along line A-A in  FIG. 19A ; 
           [0035]      FIG. 20  is a perspective view of a sheet (partly broken away) used in the cowling assembly, the sheet having heating wires for deicing the sheet in cold weather conditions; 
           [0036]      FIG. 21  illustrates the sheet in a coiled configuration; 
           [0037]      FIG. 22  is a plan view of the sheet illustrating a heat blade extending across the front end thereof; 
           [0038]      FIG. 23A  is a sectional view of a roller on which the sheet is mounted and  FIG. 23B  is an end view of the roller with a coil spring installed for rewinding the sheet in event of motor failure; 
           [0039]      FIGS. 24A-24E  are sectional views of the front of a passenger vehicle illustrating installation of coiled sheets behind a front bumper of an automotive vehicle; 
           [0040]      FIG. 25  is a perspective view of another embodiment of the cowling assembly for controlling air flow to the radiator of the vehicle; 
           [0041]      FIG. 26A  is a perspective view of a 4-track cowling and  FIG. 26B  is a front view of the cowling; and, 
           [0042]      FIGS. 27A-27C  are respective views of the assembly with the air passages open ( FIG. 27A ), partially closed ( FIG. 27B ), and top plan view ( FIG. 27C ) of the assembly in its partially closed configuration. 
       
    
    
       [0043]    Corresponding reference characters indicate corresponding parts throughout the several views of the drawings. 
       DETAILED DESCRIPTION OF INVENTION 
       [0044]    Referring to the drawings, an over-the-road vehicle V comprises a truck K towing a trailer T. As is known in the art, because of the size and shape of the truck and trailer, flow of air over and about the vehicle creates a drag which has to be overcome as the vehicle moves over a roadway; and this, in turn, reduces the vehicle&#39;s fuel efficiency. In an effort to reduce drag, a fairing such as the exemplary fairing F shown in  FIG. 1  is installed atop the truck&#39;s cab. As previously discussed, a radiator R installed on the front of the truck, under its hood H and behind its front bumper B, creates significant drag, and heretofore, no significant attempts have been made to improve the aerodynamics of the airflow about the radiator. Radiator R typically presents a generally flat rectangular shaped surface against which the air buffets and creates the drag. 
         [0045]    Referring to  FIGS. 2A-2D , a cowling assembly  10  is for a radiator which is generally taller than it is wide. As described herein, cowling assembly  10  is integrally formed with a hood H of truck K, or the cowling is attached or retro-fitted to the hood. Cowling  10  first includes a frame  12  which fits about the top and sides of the radiator so to install the cowling in place. Frame  12  is preferably of a molded lightweight plastic, single piece construction; although, it can be made of a lightweight metal. As shown in  FIG. 2A , the frame comprises upper and lower horizontal segments  13   a  and  13   b , and vertical side sections or sidewalls  13   c  and  13   d.  When installed, frame  12  defines an opening through which air can flow into the radiator. 
         [0046]    Mounted in frame  12  are a series of panels  14   a - 14   d  which are made of a plastic or lightweight metal. It will be understood that there could be more, or fewer, panels than are shown throughout the drawings. The panels are inserted in frame  12  through tracks (not shown) which are formed in the interior walls of frame sections  13   c,    13   d . The tracks may be heated tracks. The panels define air flow passages or air tunnels P for air directed through cowling assembly  10  to radiator R. Each panel is generally rectangular in shape and sufficiently sturdy that its shape is not distorted when the vehicle is moving at highway speeds; and, the sides or tips of the panels are sufficiently rigid that they do not bow or flex out of the tracks in which they are installed. Each panel may also have a rigid outer tip end (not shown) installed on it to prevent flexure. 
         [0047]    As shown in  FIG. 2A , while each panel is of the same width, the depth of the panels varies. That is panel  14   a  is the narrowest in depth and panel  14   d  the greatest. Panels  14   b  and  14   c  have widths intermediate those of these other two panels. 
         [0048]    Referring to FIGS.  2 C and  3 A- 3 C, cowling assembly  10  is shown in relation to the front end of truck K, hood H, and radiator R. As shown in the drawings, the cowling assembly is attached or mounted to the front of the hood so that frame  12  of the assembly covers radiator R. A sheet or flexible cover panel  18 , hereafter cover panel or cover, is movable by a drive mechanism  20 , as described below, over the front of the radiator to block or unblock the air flow passages P defined by the panels  14   a - 14   d  and frame  12 . This is as shown in  FIG. 3B  in which cover panel  18  is moved to substantially block all air flow to the radiator.  FIG. 3C  illustrates the operating condition in which cover panel  18  is substantially withdrawn from the front of assembly  10  for the passages P to allow significant air flow to the radiator. As discussed hereafter, a curved track  17  (see  FIGS. 12-14 ,  26 A and  26 B) is formed on the inner wall of each frame section  13   c ,  13   d  to capture the outer margin of the cover panel or sheet and guide its movement back and forth. It will be understood by those skilled in the art that track  17  may be heated to insure smooth and free movement of a cover panel or sheet over the front of the radiator in cold and icy conditions. No guide track  17  is, however, required if cover panel  18  has a slightly curved contour and is relatively rigid in construction. 
         [0049]    Referring to  FIGS. 16-19B , cowling assembly  10  may employ a series of cover panels  18  interconnected as shown in the drawings. In  FIG. 16 , the cover is shown to be made from a sheet of lightweight plastic material having a honeycomb construction. Cells  18   a  of the sheet are hollow cells. The cells provide strength and durability and promote a lightweight construction. It will be appreciated by those skilled in the art that the panel may be coated with a thin film of material to, for example, effect heating of the panel, or to protect the panel from degradation due to exposure to sunlight or various pollutants. 
         [0050]    In  FIG. 17 , three cover panels  18  are shown to be interconnected for use with the cowling assembly. Again it will be understood that cowling assembly  10  may employ more or fewer panels depending upon the particular vehicle installation. As shown in the drawings, when more than one cover panel  18  is to be joined together, the abutting edges of the panels are appropriately beveled as indicated at  18   b  and  18   c . Interconnection of the panels is achieved using a plurality of shear pins SP which are inserted through holes  18   d  formed in the respective abutting ends of the panels. Referring to  FIGS. 19A and 19B , a shear pin SP is shown to have generally cylindrical shape with sections SPa and SPb at each end which are greater in diameter than the center section SPc of the pin. 
         [0051]      FIGS. 4A-4D  respectively illustrate cowling assembly  10  from different perspectives when the assembly is in a position similar to that shown in  FIG. 3B . As shown in  FIGS. 4C and 4D , a toothed gear  26  of drive mechanism  20  extends through an opening O in the top of hood H. Adjacent each side of sheet  18  forming a cover panel are a series of equidistantly spaced holes  19  by which toothed gears  26  of drive mechanism  20  move cover panel  18  back and forth over the front of cowling assembly  10  and radiator R. The gears are mounted beneath hood H and extend through the openings O in the top of the hood for teeth  26   t  of each gear to engage the holes along the respective sides of the cover panel. 
         [0052]    Inwardly from each respective series of spaced holes  19  is an aperture  32 . The hook end  34  of a constant tension spring assembly  36  is fitted into each aperture  32 . The tension spring assembly provides a “fail safe” in the event of failure of drive mechanism  20  so to return cover panel  18  to its fully withdrawn position in which radiator R is completely open to air flow. The spring assembly is installed beneath hood H and the spring elements project through openings  38  in the top of the hood. A mounting base  40  for assembly  36  is shown in  FIG. 4C . 
         [0053]      FIGS. 5A-5E  and  6 A- 6 C illustrate a second embodiment  100  of the cowling assembly. Assembly  100  has the same basic construction features as described above with respect to assembly  10 . Now, however, assembly  100  includes a set of tracks  28   a,    28   b  which extend longitudinally of hood H, parallel to each other along opposite sides of the hood. The tracks  28   a ,  28   b  interconnect with the tracks  17  formed in frame  12  for cover panel  18  to further be drawn back and forth over both sets of tracks, particularly as shown in  FIGS. 6A-6C  to open the front of radiator R to air flow. Again adjacent each side of cover panel  18  are a series of equidistantly spaced holes  19  which are engaged by toothed gears  26  of drive mechanism  20  to move cover panel  18  back and forth over the front of cowling assembly  10  and radiator R. In this regard,  FIGS. 6A-6C  respectively illustrate approximate 30%, 50%, and 70% openings of radiator R. 
         [0054]    Tracks  28   a ,  28   b  are better shown in  FIGS. 7A and 7B . Each track has a horizontal flange  130  which abuts against the roof of hood H when the rail is mounted in place. A vertically extending flange  132  depends from the base of flange  130  and extends through an opening (not shown) in the top of the hood to mount a rail to the hood. Flange  132  has a hole  134  for connecting parts of drive mechanism  20  to the rail as will be described. Spaced holes  136  are formed on the inner section of flange  130  for mounting attachments (screws, bolts, etc.) to be fitted in place to attach the track to the hood. Each rail has a vertical section  140  projecting above the top of the hood, and a generally rectangular shaped race or track  142  is formed in an inner face  144  of section  140 . The outer ends of cover panels  18  are received in the tracks which serve as guides for movement of the panels through the track. 
         [0055]    Referring to  FIGS. 8A-8C ,  9 A- 9 C, and  10 A- 10 C, a drive mechanism  20  is for use with the first embodiment  10  of the cowling assembly and a drive mechanism  20 ′ for use with second embodiment  100  of the assembly. In drive mechanism  20 , a tooth  26 t of respective toothed gears  26  engages holes  19  along the respective sides of panel  18 . The gears  26  are bi-directionally driven by respective motors  50 . To accomplish this, each motor  50  is connected to a pulley  54  by a drive shaft  56  to rotate the pulley in the appropriate direction. Pulley  54 , in turn, is connected to a pulley  58  by a belt  52 . Gear  26  and pulley  58  are commonly mounted on a shaft  60 . 
         [0056]    For cowling assembly  100 , drive mechanism  20 ′ has one end of each shaft  60  installed in the opening  134  in vertical flange  132  of the respective tracks  28   a ,  28   b  so to mount the entire assembly in place. A sensor  51  installed on each motor provides control information to a controller for the assembly as will be described. 
         [0057]    In  FIGS. 11A-11B , a third embodiment  20 ″ of the drive mechanism is also for use with embodiment  100  of the cowling assembly. Now, a motor  50 ′ drives both toothed gears  26 . Each gear is mounted to one end of a drive shaft  66  whose other end is connected to the motor. As shown in the drawings, motor  50 ′ is mounted midway between the rails  28   a,    28   b.    
         [0058]      FIGS. 12-14  illustrate three alternate ways in which a cover panel  18  of cowling assembly  10  can be moved over and away from the front of radiator R. In the embodiment of  FIG. 12 , a wire  70  is attached to the front end of the cover panel. One end of wire  70  is connected to a bracket  72  which extends across the front of the panel (see  FIG. 18B ). The wire extends through track  17  and winds around a spool  74 . The other end of the wire then connects to motor  50 . 
         [0059]    In the embodiment of  FIG. 13 , wire  70  is attached to the rear of cover  18 . The wire then extends, not through track  17 , but rather below the panel, around spool  74  which is now attached to the inner face of the frame sections  13   c ,  13   d.  The other end of the wire is again connected to motor  50 . 
         [0060]    In the embodiment of  FIG. 14 , a rod  76  is disposed in a pneumatic or hydraulic cylinder  78 . The outer end of the rod attached to the front end of cover panel  18 . When a vacuum is applied to cylinder  78 , rod  76  is drawn into the cylinder pulling cover  18  forward along track  17 . When the vacuum is released, the rod, which is spring loaded, extends out from the cylinder, causing the panel to be pushed back along track  17 . 
         [0061]    Referring to  FIGS. 15A-15C , a controller  80  of the invention controls operation of the cowling and its panels using a microprocessor (μP)  82  which can be incorporated into the electronic control module (ECM)  84  of the vehicle or can be a standalone processor. As is known in the art, motor  50  is a bi-directional DC motor which is supplied power from the vehicle&#39;s battery BATT through a solenoid switch  86  whose operation is controlled by an output from the microprocessor. A variety of inputs are supplied to microprocessor  82  from sensors installed on or about the vehicle. These include, but are not limited to, the ambient air temperature, vehicle speed, and position sensors that indicate the degree of coverage of the radiator by the panels. The microprocessor is programmed to utilize this information to determine a) if the radiator should be covered; and b) if so, how much of it should be covered. If the conditions are such that there should be coverage, then an output is supplied from the microprocessor to solenoid  86  so DC voltage is supplied to motor  50  to drive the motor in the appropriate direction to move or adjust the panel(s) to affect the desired amount of radiator coverage. Sensors  88 ,  90  installed on or about the cowling provide information to the microprocessor as to the position of the panels for the microprocessor to stop motor  50  when the panel is in position. One sensor indicates when the panel has reached its farthest extended position and the other sensor its fully retracted position. As noted, the encoders  51  on each motor also provide exact position information. 
         [0062]    Besides the cover panels  18  previously described, cowling assemblies  10  and  100  can also employ a sheet of material for covering the radiator. Referring to  FIG. 20 , a sheet  118  comprises a thin sheet of material. Preferably embodied in the sheet are electrically conductive wires  120  which allow the sheet to be heated in cold weather conditions. This makes it easier to operate the assembly in snow, sleet, and icy conditions. Further in this regard, and as shown in  FIG. 22 , a heated strip  121  extends across the front of sheet  118 . 
         [0063]    Extending from one end of sheet  118  is a coiled strip  122 . As shown in  FIG. 21 , strip  122  facilitates installation of sheet  118  on a roller  124  from which it is unwound when radiator R is be covered, and rewound when the radiator is to be uncovered. The coiled end of strip  122  is received on a round hub  126  which projects outwardly from an outer end of the roller. 
         [0064]    Referring to  FIGS. 23A and 23B ,  FIG. 23A  shows sheet  118  as installed on the roller, which has a spiral shaped shaft  127  used to rotate the roller when it is driven by motor  50  in one direction or the other.  FIG. 23B  shows a coil spring  128  which is used to bias roller  124  to its sheet  188  retracted position. The spring provides for fail-safe operation in the event of motor failure since the spring would rewind the sheet on the roller. 
         [0065]    Next,  FIG. 25  represents another embodiment of the invention. Here, a cowling assembly  300  includes a frame  312  having top, bottom, and side members  312   a - 312   d,  bottom frame member  312   b  not being shown in the drawing. Assembly  300  includes interconnecting horizontal and vertical panels  314   a - 314   g  and  316   a - 316   g  respectively. These intersecting panels form cells of different sizes with each cell defining an air flow passage P for directing air to radiator R. 
         [0066]      FIGS. 26A and 26B  illustrate an embodiment  500  of the invention which is a variation of the embodiment shown in  FIG. 25 . Cowling assembly  500  includes a frame  512  having top, bottom, and side members  512   a - 512   d.  Assembly  500  includes interconnecting horizontal and vertical panels  514   a   1 - 514   c   3  and  516   a,    516   b  respectively. These intersecting panels again form cells of different sizes and define air flow passages P for directing air to radiator R. Running along the inside of each sidewall or vertical panel is a track  17  for guiding movement of a cover panel  18  or coiled sheet. As shown in  FIGS. 27A-27C , assembly  500  utilizes three sets of cover panels  518  which are respectively movable along paths defined by tracks  528   a - 528   d  constructed in the same manner as the previously described tracks  28   a ,  28   b.  Each cover panel  518  has sets of openings  19  formed along each longitudinal edge, these openings being engaged by teeth is a toothed gear  526  which is similar to the gear  26  previously described and driven in the same manner. Inwardly from each respective series of spaced holes  19  is an aperture  572  in which the hook end  574  of a constant tension spring assembly  576  is fitted. As earlier described with respect to tension spring assembly  36 , tension spring assembly  576  provides a fail-safe in the event of failure of the drive mechanism by which the cover panels  518  are moved, so to return a cover panel to its fully withdrawn position. 
         [0067]    As previously noted, the cowling assembly of the present invention can be used on passenger vehicles as well as trucks.  FIGS. 24A-24E  illustrate different configurations of a cowling assembly  400  for this purpose. The drawings each show a sectional view of the front end of a passenger car PC which includes a radiator R installed behind a front grill, of indicated generally FG, of the vehicle and which includes a manufacturer&#39;s emblem E. The front grill, besides extending generally across the front of the car, also extends from the hood HD of the vehicle, to the front bumper FB of the vehicle, and below the bumper to a lower cross member CM which extends across the front of the car beneath the radiator. 
         [0068]    As shown in  FIG. 24A , control of air flow to radiator R through grill FG is accomplished by moving a pair of cover panels  18 U and  18 L over the front grill. Panel  18 U is an upper panel which is drawn down from the underside of hood HD over the front grill. Panel  18 L is a lower panel which is drawn up over cross member CM toward front bumper FB along the lower extension of the grill. Upper and lower tracks  402  and  404  are respectively installed beneath the hood and over the cross member to guide movement of the panels. It will be understood by those skilled in the art that while the panels  18 U and  18 L extend over one side of the grill assembly FG, they could alternately be installed so to move over the other side of the assembly. Further, it will be appreciated that because of the construction of the grill assembly and components (e.g., headlight assemblies, etc.) installed adjacent or about the grill that the panels may be deformed or distorted as they move along their paths over the front of radiator R. This is also so as respect the other constructions described hereafter. 
         [0069]    As described with respect to  FIGS. 24D-24E , the panels for covering radiator R also include coiled sheets  118  wound on rollers  124 . As with the panels, the coiled sheets are fitted beneath hood HD, and in an undercarriage panel adjacent cross member CM, as well as in the area of bumper FB. 
         [0070]    In the embodiment of cowling assembly  400  shown in  FIG. 24B , a lower coiled sheet  118 L is unwound from a motor driven spool roller  124  to move the sheet over the underside of the grill toward bumper FB. At the same time, a panel  18 U is movable through track  402  to cover the upper portion of the grill. 
         [0071]    In  FIG. 24C , coiled sheet  418 L is unwound from roller  124  which is installed beneath hood HD; while, lower coiled sheet  118 L is unwound from its roller and moves as previously described. 
         [0072]    In  FIG. 24D , coiled sheet  118 U is unwound as described in  FIG. 23C ; while, lower sheet  118 L is unwound from a roller now placed behind front bumper FB and so moves in the opposite direction to that previously described. 
         [0073]    Lastly, in the simplified representation of  FIG. 24E  both spools  124  for the respective sheets  118 U and  118 L are installed behind the front bumper. 
         [0074]    What has been described is a cowling assembly which can be installed on a truck or passenger vehicle either as original equipment, or as a retrofit. The cowling, when installed, produces an aerodynamic airflow over, under, and about the sides of the vehicle to significantly reduce drag and improve fuel efficiency. Various embodiments of the assembly employ sheets, coils, or panels mounted in the frame or incorporated in the grill or hood of the vehicle. Regardless of the construction, the result is an aerodynamic configuration which reduces drag and promotes fuel economy. 
         [0075]    The cowling is heated so to prevent freeze up during cold, sleet, ice and snow conditions. 
         [0076]    Movement of the sheets, coils, or panels is controlled by a controller programmed for the vehicle on which the cowling is installed. The controller is either stand-alone or is incorporated into the ECM of the vehicle. 
         [0077]    The cowling assembly is relatively lightweight, and is easy to install, remove, and service. The cowling is relatively low cost and has a long life. In use, the cowling restores a significant amount of horsepower otherwise wasted by vehicles as currently configured and helps realize substantial annual fuel savings particularly for fleet of trucks. Those skilled in the art will appreciate that a cowling installed on a passenger car will achieve similar advantageous results.