Abstract:
A vehicle or trailer assembly is disclosed comprising at least one fan positioned on an exterior of the vehicle or trailer, wherein the at least one fan redirects or accelerates air moving over, around, or through the exterior of the vehicle or trailer. Also disclosed is a fan assembly comprising a manifold configured to be positioned on an outside surface of a vehicle, along an axis transverse to a direction of travel of the vehicle. The fan assembly also includes a plurality of motorized fans rotatably mounted along the axis of the manifold, such that the motorized fans are configured to accelerate air passing along the outside surface or within an exterior of the vehicle, in the direction of travel of the vehicle.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This patent application claims the benefit of priority under 35 U.S.C. § 119 to U.S. Provisional Patent Application No. 62/425,671 filed Nov. 23, 2016, and to U.S. Provisional Patent Application No. 62/363,472 filed Jul. 18, 2016, both of which are herein incorporated by reference in their entireties. 
     
    
     TECHNICAL FIELD 
       [0002]    Various aspects of the present disclosure relate generally to devices, systems, and methods configured to improve fuel economy and/or aerodynamics in moving vehicles. More specifically, the present disclosure relates to aerodynamic devices, systems, and methods for improving fuel economy and/or aerodynamics in moving vehicles. 
       BACKGROUND 
       [0003]    According to the American Trucking Association, trucks move more than 9.4 billion tons of freight in the U.S. every year. This represents 68.5% of all freight by tonnage and over $642 billion of revenue, or about 81% of revenue from all U.S. freight transport modes. This vital industry has grown in importance as customers now expect to receive shipped items within days or even hours, a value proposition that only the versatility and speed of trucking can match. Additionally, new end customer demands for speed mean business-to-business transactions must happen faster. 
         [0004]    As a result of the push for faster and cheaper delivery, efficiency is at a premium. The Department of Transportation estimates that trucks on U.S. highways consume more than 43 billion gallons of fuel annually. That represents over 1,700 gallons per vehicle and just 7.3 miles per gallon. This consumption also represents a significant contribution to greenhouse gases and air pollution. While strides have been made in cleaning air output in diesel engines, fuel efficiency remains unaddressed. Improving fuel efficiency reduces total fuel usage and helps the trucking industry to be more sustainable, while also meeting the growing performance demands stemming from customer delivery preferences. An electrically powered truck consumes less fuel, but producing, transmitting, and storing of that electricity likely still requires fuel. Furthermore, an electrically powered truck does not move through the air more efficiently than a gas or diesel powered truck. 
         [0005]    Fuel efficiency may be improved by looking beyond the powertrain. Of course, the power train and simple rolling resistance are key contributors to fuel efficiency, but as trucks reach highway speeds, resistance from air friction and pressure friction causes up to 70% of fuel burn or other energy consumption. Pressure drag represents more than 90% of total drag. While existing accessory products on the market promise to improve drag efficiency by redirecting air, most products only contribute to marginal gains and lack durability. New products able to generate increased gains at a lower cost may improve fuel burn and energy consumption efficiency. Moreover, devices, systems, or methods that improve fuel burn and energy consumption efficiency in tractors and trailers may apply to other vehicles, even though the size and shapes may differ. 
         [0006]    The devices and methods of the current disclosure may rectify some of the deficiencies described above or address other aspects of the prior art. 
       SUMMARY 
       [0007]    Examples of the present disclosure relate to, among other things, aerodynamic devices for moving vehicles. Each of the examples disclosed herein may include one or more of the features described in connection with any of the other disclosed examples. 
         [0008]    Aspects of this disclosure may improve upon past efforts to achieve efficiency through trailer design by focusing primarily on pressure drag improvements and on air and road friction improvements. Rather than redirecting air flowing past a vehicle or trailer, aspects of the present disclosure use fans and other devices to generate air flow and/or accelerate the air passing the trailer or tractor, thus reducing speed differential and allowing the trailer or tractor to pass through air with less pressure and friction drag. These air speed-changing devices may be placed at various locations, for example, the sides, top, undercarriage, and/or aft of the vehicle or trailer. These devices may be positioned in multiple locations across the trailer and may be used in conjunction with other data sensors, such as, for example, wind speed indicators, to allow the air speed-changing devices to assist in reducing drag and instability due to cross winds and improving fuel efficiency. The air speed devices may also provide lift by thrusting downward, and such downward positioning may reduce road friction and improve fuel efficiency. Furthermore, the air speed devices may be controlled and/or programmed to correlate to the wind speed, that is, the speed at which the vehicle is moving relative to the air, rather than to the ground. For example, the data sensors may detect the wind speed, and may signal and/or control the power and/or programming of the air speed devices such that the air speed devices accelerate the air passing the trailer or tractor to match or to approximate the wind speed. 
         [0009]    Several additional features may potentially enhance the benefits of the air speed devices. In one instance, the devices may have the ability to reverse thrust, which may allow more efficient braking, save energy, and reduce wear on the drive train (i.e., reducing the use of engine braking) and brake pads. This reverse thrust may be combined with flaps to create beneficial drag when desired. 
         [0010]    In another instance, in some cases, an air speed device may become a parasitic load on a tractor&#39;s battery system or reduce efficiency gains through the device&#39;s additional weight. Depending on the cargo carried by the trailer and the duty cycle (e.g., extended highway time vs. short trips to relay merchandise between local warehousing), small solar panels may be added to the trailer roof to improve the efficiency of the battery system, exploiting an underutilized surface when used in combination with an auxiliary battery system. Alternatively, an air speed device may be powered by any power source, including a combustion engine, such as, for example, the engine of the tractor, an electric engine, a hybrid engine, or any other power source. The air speed devices may also have a weight such that their net benefit remains positive. As such, the air speed device may be constructed of various light, yet strong, materials. 
         [0011]    Both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the features, as claimed. As used herein, the terms “comprises,” “comprising,” “including,” “having,” or other variations thereof, are intended to cover a non-exclusive inclusion such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements, but may include other elements not expressly listed or inherent to such a process, method, article, or apparatus. Additionally, the term “exemplary” is used herein in the sense of “example,” rather than “ideal.” It should be noted that all numeric values disclosed or claimed herein (including all disclosed values, limits, and ranges) may have a variation of +/−10% (unless a different variation is specified) from the disclosed numeric value. Moreover, in the claims, values, limits, and/or ranges means the value, limit, and/or range +/−10%. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate exemplary features of the present disclosure and together with the description, serve to explain the principles of the disclosure. There are many aspects and embodiments described herein. Those of ordinary skill in the art will readily recognize that the features of a particular aspect or embodiment may be used in conjunction with the features of any or all of the other aspects or embodiments described in this disclosure. 
           [0013]      FIG. 1  illustrates an exemplary air acceleration trailer system, according to aspects of this disclosure. 
           [0014]      FIG. 2  illustrates a rear view of an exemplary air acceleration trailer system, according to aspects of this disclosure. 
           [0015]      FIG. 3  illustrates a portion of the rear view of the exemplary air acceleration trailer system of  FIG. 2 , according to aspects of this disclosure. 
           [0016]      FIGS. 4A and 4B  illustrate side views of exemplary air acceleration elements, according to aspects of this disclosure. 
           [0017]      FIGS. 5A and 5B  illustrate cross-section views of exemplary air acceleration elements, according to aspects of this disclosure. 
           [0018]      FIGS. 6A and 6B  illustrate end views of exemplary air acceleration elements, according to aspects of this disclosure. 
           [0019]      FIG. 7  illustrates an additional exemplary air acceleration trailer system, according to further aspects of this disclosure. 
           [0020]      FIG. 8  illustrates an additional exemplary air acceleration trailer system, according to further aspects of this disclosure. 
           [0021]      FIG. 9  illustrates an additional exemplary air acceleration trailer system, according to further aspects of this disclosure. 
           [0022]      FIG. 10  illustrates a top view of a portion of the air acceleration trailer system of  FIG. 9 , according to aspects of this disclosure. 
           [0023]      FIG. 11  illustrates a side view of a portion of the air acceleration trailer system of  FIG. 9 , according to aspects of this disclosure. 
           [0024]      FIG. 12  illustrates a cross-section view of a portion of the air acceleration trailer system of  FIG. 9 , according to aspects of this disclosure. 
           [0025]      FIG. 13  illustrates an additional exemplary air acceleration trailer system, according to further aspects of this disclosure. 
           [0026]      FIG. 14  illustrates an additional exemplary air acceleration trailer system, according to further aspects of this disclosure. 
           [0027]      FIGS. 15A and 15B  illustrate cross-section views of exemplary air acceleration elements, according to aspects of this disclosure. 
           [0028]      FIGS. 16A and 16B  illustrate cross-section views of additional exemplary air acceleration elements, according to aspects of this disclosure. 
           [0029]      FIG. 17  illustrates a cross-section view of an exemplary air acceleration element, according to aspects of this disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0030]    Examples of the present disclosure relate to devices and systems configured to improve vehicular energy efficiency. The devices and systems may be used to improve aerodynamics by reducing drag, and thus improving fuel efficiency. 
         [0031]    Reference will now be made in detail to examples of the present disclosure described above and illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. 
         [0032]    According to aspects, as detailed in  FIG. 1 , a trailer system  10  may include a tractor or cab  12  and a trailer  14 , with a plurality of air speed devices or fans  16  mounted on or otherwise positioned on trailer  14 . Fans  16  may be arranged in one or more groups or bands  18 . Trailer system  10  may also include one or more solar panels  20  and/or a battery pack  22 . 
         [0033]    Cab  12  may be a tractor-trailer type cab, which may be powered by a diesel engine, electric engine, hybrid engine, or any other power source. Cab  12  may include any appropriate coupling to trailer  14 . The coupling may include an electrical connection as well, such that electricity and other signals may be transmitted between cab  12  and trailer  14 . 
         [0034]    Trailer  14  may be any appropriate trailer, either integral with cab  12  or otherwise coupled to cab  12  such that cab  12  may pull trailer  14 . Trailer  14  includes a front portion  24  and a rear portion  26 , with front portion being closer to cab  12  and rear portion  26  being farther away from cab  12 . 
         [0035]    While the present disclosure and drawings are described in the context of semi-or tractor-trailer-type trucks, it should be appreciated that the presently disclosed devices and systems may be applicable to any moving vehicle, ranging from passenger cars, including SUVs and buses, to freight trains or locomotives. Moreover, the presently disclosed devices and systems may be applicable to any type of cargo trucks, including box-type trucks, delivery vans, or the like. 
         [0036]    As mentioned, fans  16  may be arranged in one or more bands  18 , and may be mounted on or otherwise coupled to trailer  14 . Fans  16 , which may also be other pump devices, may redirect and/or accelerate air passing over or around trailer  14 . Fans  16  may be mounted on an existing trailer  14 , or may be integrally produced with trailer  14 . Bands  18  of fans  16  may be positioned on a top, both sides, and a bottom of trailer  14 . As shown in  FIG. 1 , bands  18  of fans  16  may be positioned at rear portion  26  of trailer  14 . Fans  16  may be arranged such that one band  18  is on the top, one band  18  is on each side, and one band  18  is on the bottom of trailer  14 . Alternatively, multiple bands  18  of fans  16  may be positioned on the top, each side, and the bottom of trailer  14 . 
         [0037]    One or more solar panels  20  may be positioned on the top of trailer  14 , and battery pack  22  may be positioned within or mounted on, for example, the bottom or underside, of trailer  14 . Solar panels  20  and battery pack  22  may be electrically coupled to fans  16  to generate and/or deliver power to operate fans  16 . Solar panels  20  may also be electrically coupled to battery pack  22  to store collected energy to be saved for later use. Solar panels  20  and battery pack  22  may allow for fans  16  to be operated separate from the engine and other electrical components of cab  12 . Furthermore, solar panels  20  and battery pack  22  may be electrically coupled to cab  12  to deliver energy to power electrical components of cab  12 , potentially reducing the fuel and battery consumption of cab  12 . 
         [0038]    As shown in  FIGS. 2 and 3 , in one aspect, fans  16  may be positioned in the same plane as a rear face  28  of trailer  14 . Rear face  28  may include at least one door, and fans  16  may be integral with the at least one door, or may be positioned around a perimeter or an exterior of the at least one door. In this aspect, although not shown, fans  16  may include an inlet duct for air to be taken in and accelerated by fans  16 . Fans  16  may include one or more blades  30 , which may be powered by small electric motors. Blades  30  may be relatively small, rigid, rotating blades, and may be integrated into a groove or channel in order to ensure aerodynamic efficiency. In an example, each fan  16  may include one, two, three, four, or even a multitude of blades  30 . Each blade  30  may be made from a light, but strong material, including, for example, carbon fiber, graphite fiber, plastic, or other similar materials. 
         [0039]      FIGS. 4A and 4B  illustrate cross-section views of various types of fans  16 .  FIG. 4A  includes fan  16  in a manifold or housing  32 . Housing  32  may include an attachment or hole  34  for a bolt or other element to secure housing  32  to trailer  14 , and although not shown, hole  34  may be threaded. For example, bands  18  of fans  16  may be bolted to trailer  14 , as shown in  FIG. 1 , to retrofit trailer  14  with fans  16 . Each fan  16  may be separately secured to trailer  14  using, for example, bolts, screw, or welding, or band  18  of fans  16  may be secured to trailer  14 . Housing  32  may also include one or more screens  36 , for example, on one or both of front and back sides of fan  16 . Screens  36  may protect fan  16  and/or ensure that debris or other materials do not interfere with fan  16  and blades  30 . Housing  32  may also contain the electric motor and other elements that power blades  30 . Housing  32  may further include a securing element  38  to couple a top portion  40  to a bottom portion  42 . As shown in  FIG. 4B , fan  16 ′ may be a scroll fan or centrifugal fan. System  10  may include a mixture of fans  16  with blades  30  and scroll fans  16 ′. 
         [0040]      FIGS. 5A and 5B  illustrate end views of a plurality fans  16  and a portion of fan  16 ′, respectively.  FIGS. 6A and 6B  illustrate a plurality of bands  18  and  18 ′ of fans  16  and  16 ′. As shown in  FIG. 6A , band  18  may include, for example, twelve fans  16 , and four bands  18  may be positioned on, for example, a top side of trailer  14 . Four bands  18  may be approximately 2.54 meters (100 inches), and may correspond to the top side of trailer  14 . As shown in  FIG. 6B , a band  18 ′ may include, for example, three scroll fans  16 ′, and four bands  18 ′ may be positioned on, for example, a top side of trailer  14 . Four bands  18 ′ may be approximately 2.54 meters (100 inches), and may correspond to the top side of trailer  14 . In both  FIGS. 6A and 6B , although not shown, solar panels  20 , may be included above or in front of bands  18 ,  18 ′ along the length of trailer  14 , or may be otherwise positioned on trailer  14  as discussed above. 
         [0041]    The operation of fans  16  may aid in reducing drag and/or achieve aerodynamic braking, thus improving fuel efficiency. If fans  16  are employed to direct and/or accelerate air toward the rear of trailer  14  or straight back behind trailer  14 , trailer  14  may move more efficiently through the air. Furthermore, fans  16  may be angled to direct air toward the center of the rear of the trailer  14 , that is, with fans  16  on a top of trailer  14  directed downward, fans  16  on the sides of trailer  14  directed inward, and fans  16  on a bottom of trailer  14  directed upward. Fans  16  on the four sides of trailer  14  may direct air in a cone-like shape, which may help trailer  14  to move more efficiently through the air. If fans  16  are employed to direct and/or accelerate air toward the front of trailer  14 , trailer  14  may brake more efficiently and/or reduce wear on the brakes and other components in cab  12  and trailer  14 . Additionally, deactivating fans  16  may aid in braking and/or assist trailer system  10  to slow down by increasing the pressure drag on trailer  14 . For example, fans  16  may be electrically coupled to a brake pedal or cruise control setting within cab  12  such that fans  16  are automatically deactivated when the brake pedal is depressed or the cruise control speed is decreased. 
         [0042]    Trailer system  10  may further include at least one sensor, for example, an air or wind speed sensor to measure the speed at which trailer system  10  moves relative to the air. The at least one sensor may be operably coupled to fans  16 , for example, to the motor of fans  16 . The power generated by the motors and/or the speed at which the blades  30  move may be correlated to the values measured by the sensors. In one aspect, fans  16  may include programming and/or a controller configured to control fans  16  based on the values measured by the sensors. For example, based on the values measured by a wind speed sensor, the power and/or speed of fans  16  may be adjusted. Specifically, if trailer system  10  is facing a head wind, the power and/or speed of fans  16  may be greater than if trailer system  10  is in a tail wind. This may be the case even if trailer system  10  is traveling at the same ground speed. By controlling fans  16  in relation to a detected or sensed wind speed, trailer system  10  may experience a reduced pressure drag, which may help reduce fuel burn or power consumption. 
         [0043]      FIG. 7  illustrates an alternative example with similar elements to trailer system  10  shown by 100 added to the reference numbers. This aspect includes a trailer system  110  with a truck or cab  112 , trailer  114 , one or more solar panels  120 , and a battery pack  122 . Trailer system  110  may include two sets of bands  118 A,  118 B of fans  116 A,  116 B mounted on or otherwise coupled to trailer  114 . In this aspect, fans  116 A may be attached to rear portion  126  of trailer  114 , and may be configured to direct air toward the rear of trailer  114 . Fans  116 A may reduce the drag on trailer  114 , and may help to improve fuel efficiency. Fans  116 B may be attached to front portion  124  of trailer  114 , and be configured to direct air toward the front of trailer  114 . Fans  116 B may assist in braking, which may help to reduce wear on the brakes and other components. As discussed above, fans  116 A,  116 B, and  116 C may be electrically coupled to a brake pedal or cruise control setting within cab  112  to selectively and/or automatically control fans  116 A,  116 B, and  116 C. 
         [0044]      FIG. 8  illustrates an alternative example with similar elements to trailer system  10  shown by 200 added to the reference numbers. This aspect includes a trailer system  210  with a truck or cab  212 , trailer  214 , one or more solar panels  220 , and a battery pack  222 . It is noted that, as shown in  FIG. 8 , solar panels  220  may be discrete sets of solar panels, or may be continuous solar panels ( FIGS. 1 and 7 ). Trailer system  210  may include three sets of bands  218 A,  218 B,  218 C of fans  216 A,  216 B,  216 C mounted on or otherwise coupled to trailer  214 . In this aspect, fans  216 A may be attached to rear portion  226  of trailer  214 . Fans  216 B may be attached to a middle portion  244  of trailer  214 , and fans  216 C may be attached to front portion  224  of trailer  214 . Fans  216 A,  216 B, and  216 C may all be configured to direct air toward the rear of trailer  214 , and may reduce the drag on trailer  214 , which may help to improve fuel efficiency. Alternatively, fans  216 A and fans  216 B may direct air toward the rear of trailer  214 , and fans  216 C may direct air toward the front of trailer  214 . 
         [0045]    Turning now to  FIGS. 9-12 , the figures illustrate a further alternative example of an aerodynamic device for moving vehicles, with similar elements to trailer system  10  shown by 300 added to the reference numbers. As such, this aspect includes a trailer system  310  with a truck or cab  312 , trailer  314 , one or more solar panels  320 , and a battery pack  322 . Furthermore, trailer  314  may include a opening  346 , which internally directs airflow to interior, ducted fans  316 . As discussed above, fans (not shown) may be coupled to an exterior of trailer  314  and/or embedded in the walls of the trailer  314 . In one aspect, fans  316  may be embedded in the exterior walls of the trailer around a perimeter of the rear of trailer  314  in rear portion  326  or rear face  328 . 
         [0046]    As shown in  FIG. 9 , opening  346  may be positioned along a length of trailer  314 . Opening  346  may be positioned mid-way in the length of trailer  314 , or opening  346  may be positioned between middle portion  344  and rear portion  326  proximate to rear end  328  of trailer  314 . For example, opening  346  may be positioned approximately three-quarters or seven-eighths of the way from front to rear of trailer  314 . As shown in  FIGS. 10, 11, and 12 , opening  346  may be a longitudinal opening in the top, sides, bottom, or any portion of trailer  314 . Opening  346  may connect to fans  316  through one or more internal ducts  348  (shown in  FIGS. 10, 11, and 12 ) within the portion of trailer  314  between opening  346  and fans  316 . Opening  346  may allow for air intake such that the air taken in may be selectively accelerated by fans  316  toward the rear of trailer  314  to reduce skin friction and/or pressure drag, which may aid in improving fuel efficiency as discussed above. Furthermore, fans  316  may be angled to more effectively direct the air. Alternatively or additionally, fans  316  may direct air toward the front of trailer  314 , which may aid in achieving aerodynamic braking. Moreover, deactivating fans  316  may aid in braking and/or assist trailer system  310  to slow down by increasing the pressure drag on trailer  314 . For example, fans  316  may be electrically coupled to a brake pedal or cruise control setting within cab  312  such that fans  316  are automatically deactivated when the brake pedal is depressed or the cruise control speed is decreased. 
         [0047]      FIGS. 13 and 14  illustrate alternative positions of opening  346 ′ in trailer  314 ′ and openings  346 A and  346 B in trailer  314 ″, respectively. As shown in  FIG. 13 , opening  346 ′ may be positioned in middle portion  344 ′ of trailer  314 ′. As shown in  FIG. 14 , opening  346 A may be positioned between middle portion  344 ′ and rear portion  326 ′ of trailer  314 ″, and opening  346 B may be positioned between middle portion  344 ″ and front portion  324 ″. Trailer  314  may include any number of longitudinal openings  346  along the length of trailer  314 . Openings  346  may be evenly or unevenly distributed along the length of trailer  314 , and the plurality of openings  346  may allow for air intake such that the air taken in may be selectively accelerated by fans  316  embedded in the walls and/or on the exterior of trailer  314 . Again, fans  316  may be selectively angled to achieve aerodynamic braking and/or aid in reducing skin friction and pressure drag, thus improving fuel efficiency. Moreover, the one or more openings along the length of the trailer may be connected to each other via, for example, ducts, or may otherwise cooperate and/or work in conjunction with each other. 
         [0048]    In the example shown in  FIG. 14 , trailer  314 ″ may include a series of fans or pumps embedded in the walls of trailer  314 ″. The series of fans or pumps may be embedded in the walls between opening  346 A and opening  346 B, and may also be embedded in the walls of trailer  314  to the rear of opening  346 A. Opening  346 B may intake air, and fans  316  or pumps between opening  346 B and opening  346 A may accelerate the air before the air exits at the front of opening  346 A. Opening  346 A may also intake air, and fans  316  or pumps between opening  346  and the rear of the trailer  326 ″ may accelerate the air before the air exits at the rear of trailer  314 . Alternatively, opening  346 B and its fans  316  or pumps may intake air and accelerate the air all the way to the rear of trailer  314 , with opening  346 A and its fans or pumps taking in and accelerating more air to the rear of trailer  314 . The aforementioned openings  346 ,  346 ′,  346 A,  346 B and fans  316  or pumps both pull or suck air in and push or accelerate air out. 
         [0049]      FIGS. 15A and 15B  illustrate additional air acceleration and direction elements that may be incorporated in any of the aforementioned trailer systems  10 ,  110 ,  210 , and  310 , with similar elements to trailer system  10  shown by 400 added to the reference numbers.  FIGS. 15A and 15B  are cross-section views of exemplary rear portions  426  of trailer  414 . As shown in  FIG. 15A , fan  416  may be embedded in rear portion  426  of trailer  414 . As shown in  FIG. 15B , scroll fan  416 ′ may be embedded in rear portion  426  of trailer  414 . In both Figures, duct  448  may connect fans  416 ,  416 ′ to an opening (not shown) as in  FIGS. 9-14 . Trailer  414  may include a curved wing or projection  450 , which may extend from the top of the rear end of trailer  414 . Projection  450  may be curved and may extend at approximately a forty-five degree angle from the top of the rear end of the trailer  414  or from within duct  448 . Projection  450  may be pivotable. For example, if fan  416  is not directing air toward the rear of trailer  414 , projection  450  may hang approximately straight down, but if fan  416  is directing air toward the rear of trailer  414 , projection  450  may pivot up to the approximately forty-five degree angle. Alternatively, projection  450  may be fixed at an angle. As illustrated in  FIGS. 15A and 15B , projection  450  may direct the air from fans  416 ,  416 ′ toward a center of rear end  428  of trailer  414 . Directing the air from fans  416 ,  416 ′ may assist in recovering the pressure at the rear of trailer  414 , which may aid in reducing drag and improving fuel efficiency. Projections  450  may also be incorporated on all four sides of trailer  414  to direct air toward the center of the rear of trailer  414 , for example, in a cone-like shape. 
         [0050]      FIGS. 16A and 16B  illustrate additional air acceleration and direction elements that may be incorporated in any of the aforementioned trailer systems  10 ,  110 ,  210 , and  310 , with similar elements to trailer system  10  shown by 500 added to the reference numbers.  FIGS. 16A and 16B  are cross-section views of exemplary rear portions of trailer  514 , and fan  516  or scroll fan  516 ′ may be embedded in the rear portions of trailer  514 , respectively, and curved wings or projections  550  may be coupled to trailer  514  to direct air, as discussed above. Fans  516 ,  516 ′ may intake air from ducts  548 . In addition, trailer  514  may include a protraction or scoop  552 , which may be an angled extension that extends away from duct  548  and includes an intake opening facing toward the front of trailer  514 . In this aspect, as trailer  514  moves through the air, air may enter protraction  552 , travel through duct  548 , and be accelerated toward the rear of trailer  514  by fans  516 ,  516 ′. 
         [0051]    In a further aspect, protraction  552  may be pivotable or hinged from a position in line with the top of trailer  514 , with the ducts  548  closed, to the position shown in  FIGS. 16A and 16B . For example, protraction  552  may be automated, such that protraction  552  may extend upward when trailer  514  is moving at a specific speed, for example, at least ten miles per hour, at least twenty miles per hour, at least thirty miles per hour, at least forty miles per hour, at least fifty miles per hour, etc. Alternatively, protraction  552  may be coupled to a user input, for example, positioned in cab  12 , such that an operator may extend protractions  552  when the operator deems fit or necessary. If protraction  552  is pivotable, ducts  548  and fans  516 ,  516 ′ may be protected from debris and other elements when not in operation. Moreover, at low speeds, it may be more fuel efficient to close protractions  552  for trailer  514  to have a streamlined top. Alternatively, at higher speeds, it may be more fuel efficient to open protractions  552  and operate fans  516 ,  516 ′ and direct air to the rear of trailer  514  and recover the pressure at the rear of trailer  514 , reducing drag, etc. Furthermore, protractions  552  may include screens to ensure debris does not enter ducts  548 . Protractions  552  may also be incorporated on all four sides of trailer  514  to intake air, and projections  550  may direct air toward the center of the rear of trailer  514 , for example, in a cone-like shape. 
         [0052]      FIG. 17  illustrates additional air acceleration and direction elements that may be incorporated in any of the aforementioned trailer systems  10 ,  110 ,  210 , and  310 , with similar elements to trailer system  10  shown by 600 added to the reference numbers.  FIGS. 17  is a cross-section view of an exemplary rear portion  626  of trailer  614 , in which a fan  616  may be embedded in the wall of trailer  614 , for example, in rear face  628 . Fan  616  may intake air through duct  648  as discussed with any of the previously discussed embodiments, which may include a protraction as discussed with respect to  FIG. 16A . As shown in  FIG. 17 , fan  616  may be angled from a longitudinal axis of trailer  614 . For example, fan  616  may be positioned at approximately a forty-five degree angle. An angled fitting  654  may be coupled to at least one of fan  616  and/or rear face  628  of trailer  614 . Angled fitting  654  may retain fan  616  at the angle. Moreover, the position and/or angle of fan  616  may be adjustable. For example, as discussed above with respect to protraction  552 , when trailer  614  is not in motion or is traveling at low speeds, fan  616  may be positioned within duct  648 , and angled fitting  654  may close to protect fan  616 . At higher speeds, or based on user input, fan  616  may be angled and extend out of duct  648  to accelerate and direct air toward the rear of trailer  614  and downward toward a center of trailer  614 . 
         [0053]    Although the aspects of the foregoing figures were discussed with respect to fans  16 ,  16 ′,  116 A,  116 B,  216 A,  216 B,  216 C,  416 ,  416 ′,  516 ,  516 ′, and  616  positioned on a top portion of trailers  14 ,  114 ,  214 ,  314 ,  314 ′,  314 ″,  414 ,  514 , and  614 , the features may be employed at any position on the trailers. In particular, the fans may be positioned on all four sides of the trailers. For example, fan  416  and projection  450  may be positioned on the sides and/or bottom of trailer  414  and positioned to accelerate and direct air toward the rear of trailer  414  and either to the sides or upward toward the center of trailer  414 . Trailer  514  may include protractions  552  on the sides and/or bottom of trailer  514  to intake air to be accelerated and directed by fans  516 . Similarly, fan  616  and angled fitting  654  may be positioned on the sides and/or bottom of trailer  614  and positioned to accelerate and direct air toward the rear of trailer  614  and either to the side or upward toward a center of trailer  614 . Moreover, the air accelerated by the fans on all four sides may be directed toward the center of the trailers, for example, in a cone-like shape 
         [0054]    In the above examples, changing the airspeed of the air surrounding trailer  14 ,  114 ,  214 ,  314 ,  414 ,  514 , and  614  may assist in reducing skin friction by impacting the fluid boundary layer on the sides of the trailer to reduce the drag on the trailer. The above examples may also assist in reducing the pressure drag by recovering the pressure at the rear of the trailer by pushing air out of the rear and/or directing the air toward the center. 
         [0055]    In one aspect, opening(s)  346  and/or protractions  552  along the length of the trailer may intake air and, through the series of fans or other pumps, the air may be pulled into trailer  14 ,  114 ,  214 ,  314 ,  414 ,  514 , and  614  and accelerated out of the rear of trailer  14 ,  114 ,  214 ,  314 ,  414 ,  514 , and  614 . The direction and angle of the accelerated air out of the rear of trailer  14 ,  114 ,  214 ,  314 ,  414 ,  514 , and  614  may be selectively adjusted, as discussed. In one example, the air accelerated out of the rear of trailers  14 ,  114 ,  214 ,  314 ,  414 ,  514 , and  614  may be directed at multiple angles, particularly, inward in a cone-like shape. 
         [0056]    Furthermore, it is noted that any of the aforementioned fans or fan-type devices may include any pump-type devices to accelerate fluid, i.e., air. For example, the pump-type devices may comprise motors, jets, propellers, any device that accelerates fluid, or any combination thereof. Moreover, it is further noted that the systems discussed above may be powered by any power supply, including the vehicle&#39;s own power. For example, a device that significantly reduces the drag on a vehicle and uses minimal power may be powered by the vehicle&#39;s power without creating a parasitic load. Similarly, the systems discussed above may be powered by solar panels  20 , battery pack  22 , the vehicle&#39;s own power, or any combination thereof. Additionally, the speed of or power supplied to the fan or pump-type devices may be controlled and increased or decreased based on the vehicle speed to conserve power usage. 
         [0057]    In an aspect discussed with respect to  FIG. 7 , the fan or pump-type devices mounted on the exterior of trailer  114  may accelerate air towards the front of trailer  112 , rather than towards the rear of trailer  112 . In one example of this aspect, one series of fan or pump-like devices may be mounted on the exterior of the front portion of the trailer and may accelerate air towards the front of the trailer. Accelerating air towards the front of trailer  112  may assist in reducing skin friction drag. A different series of fan or pump-like devices may be mounted on the exterior of the rear portion of trailer  112 , or within a rear opening, to accelerate air out of the rear of trailer  112 . Accelerating air out of the rear of trailer  112  may assist in recovering the pressure at the rear of the trailer, as discussed in more detail above. 
         [0058]    The aforementioned aspects may help to achieve increased truck freight energy efficiency (reduced fuel burn or low consumption of any energy source), which may allow for faster and cheaper shipping for consumers and faster lead times for business-to-business customers, as well as increases in federal regulation standards. Addressing drag may increase efficiency with the systems discussed above and may reduce fuel burn or other energy consumption for vehicles of all sizes. Furthermore, including solar panels in the trailer systems discussed herein may harness significant solar power, as trailers and most vehicles operate almost exclusively in the outdoors. As such, the power necessary from the vehicle&#39;s own power supply may be significantly reduced. Nevertheless, including a battery pack may further provide energy stored by the solar panels when the solar panels are not generating sufficient energy, for example, at night, on cloudy days, etc. As such, the systems and features discussed above may reduce fuel burn, while also not significantly impacting the efficiency of the vehicle&#39;s own power systems. 
         [0059]    While principles of the present disclosure are described herein with reference to illustrative examples for particular applications, it should be understood that the disclosure is not limited thereto. Those having ordinary skill in the art and access to the teachings provided herein will recognize additional modifications, applications, embodiments, and substitution of equivalents all fall within the scope of the features described herein. Accordingly, the claimed features are not to be considered as limited by the foregoing description.