Multicomponent improved vehicle fuel economy system

A semitrailer comprising a main frame having a hitch, an axle assembly connected to the main frame, the axle assembly including at least two wheels for rotation relative to the main frame, a fairing connected to an underside of the semitrailer intermediate the hitch and the axle assembly, the fairing including a pair of lateral surfaces, a bottom surface spaced from the underside of the semitrailer, and a leading surface, wherein the leading surface includes an intake opening, and wherein at least one of the bottom surface or the lateral surfaces includes an exit opening, and a flow path fluidly connects the intake opening and the exit opening.

TECHNICAL FIELD

The present disclosure relates to overland vehicles and more particularly to decreasing the aerodynamic drag of such vehicles and more particularly to semitrailers.

In another configuration, the present disclosure provides a fairing system for semitrailers and particularly for semitrailers having a movable axle assembly—often referred to as a bogie or tandem. For purposes of the present disclosure, the term axle assembly is intended to be interchangeable with bogie, tandem or other equivalent terms.

BACKGROUND ART

Most of today's tractor-trailers get about 6-7 mpg of fuel leaving significant potential for improving fuel economy of tractor-trailers. Reducing the fuel consumption of tractor-trailers would directly impact transportation costs of goods, serving businesses and consumers alike.

Fuel consumption of a tractor-trailer is influenced by the amount of drag forces incurred by the vehicle while traveling. As the drag forces increase, fuel consumption also increases. One area of a semitrailer where drag forces are high is the undercarriage of a semitrailer. Another area of the semitrailer where aerodynamic forces are high is the rear end of a semitrailer container. When the tractor-trailer is traveling, air flows under and around the semitrailer, placing significant drag forces on the wheels, undercarriage and rear of the truck. The tractor-trailer must use more power to overcome the drag, thereby increasing fuel consumption. Thus, it is most desirable to reduce drag beneath the undercarriage and at the rear end of a semitrailer.

What is needed then is a drag reduction system for a semitrailer that improves fuel economy.

It would, therefore, be desirable to provide a drag reduction system for a semitrailer that overcomes the aforesaid and other disadvantages.

DISCLOSURE OF INVENTION

The present invention provides a fairing system for semitrailers for decreasing aerodynamic drag. One configuration of the invention is a drag force reduction system comprising a semitrailer having a main frame extending along a longitudinal axis and a subframe movably connected to the main frame between a first position along the longitudinal axis and a second position along the longitudinal axis. An axle assembly is attached to the subframe, wherein the axle assembly includes an axle, a plurality of wheels and a suspension. A fairing is located under the main frame and is separated from the axle assembly along the longitudinal axis by a given spacing. The fairing is movable relative to the main frame to maintain the given spacing between the axle assembly and the fairing independent of the subframe and hence axle assembly being in the first position or the second position. In one configuration, the fairing is slidably connected to the main frame. In another configuration, the fairing is slidably connected to the axle assembly.

The fairing can include a fairing frame having a mounting portion and a frame retaining portion, wherein the mounting portion is movable relative to the retaining portion along the longitudinal axis. In one configuration, the fairing is affixed to one of the axle assembly and the subframe at a given spacing, which may be adjustable within a predetermined fairing range of motion. In one configuration, the fairing is connected to the subframe and translatable relative to the subframe. The fairing includes an aerodynamic structure formed of one of metal, aluminum, plastic, ABS, Poly Carbonate, TPO and other polymers.

In one configuration, the fairing includes a bottom and a leading apex formed of a plurality of converging planar regions. The fairing includes a bottom surface and a trailing surface, a leading surface and lateral surfaces, the bottom surface and the trailing surface substantially enclosing a volume beneath the semitrailer. A plurality of lighting elements can be disposed along at least a portion of the fairing.

The fairing can include an intake opening and at least one flow path fluidly connecting the intake opening and an exit-opening formed in the fairing. The at least one flow path may include at least one venting duct extending from the intake opening to the at least one exit-opening. The at least one exit-opening has a cross-sectional area less than a cross-sectional area of the intake opening. The at least one exit-opening can have a cross-sectional area equal to a cross-sectional area of the intake opening.

In a configuration, the main frame further includes a plurality of elongate beams extending along a longitudinal axis and a plurality of cross beams connected to the elongate beams and extending transverse to the longitudinal axis, an upper surface of the cross beams and the elongate beams supporting a decking, and the decking, the elongate beams and the cross beams defining a plurality of cavities opening to an underside of the semitrailer, wherein a covering on an underside of the semitrailer substantially occludes the plurality of cavities. The covering can be connected to the elongate beams and the cross beams. A portion of the covering can be disposed between the wheels and one of the elongate beams and the cross beams. The covering can be selected from the group consisting of a polymer, composite, laminate, metal, and plastic.

In another configuration, a semitrailer comprises a main frame, hitch a wheel set connected to the main frame, the wheel set including at least two wheels for rotation relative to the main frame, a closable container on the main frame, the container having a rear end and a pair of doors movable between a closed position and an open position, each door hingedly connected to the container to pivot about a vertical axis, a vertical flap, at least an upper hinge and a lower hinge hingedly connected to one of the doors and the vertical flap to pivot the vertical flap about a vertical axis, and an interconnector extending between the upper hinge and the lower hinge, such that upon movement of the lower hinge from an open configuration to a closed configuration, the upper hinge moves from an open configuration to a closed configuration. The interconnector may have a u-shaped base having two legs and a closed end rotatably connected to one of the doors and two legs, each leg pivotally coupled to the upper hinge and lower hinge, respectively. The interconnector, in one configuration, is a bar connected to the upper hinge and lower hinge. The semitrailer can further comprise a horizontal top flap and a top hinge connected to one of the doors and the horizontal top flap to pivot the horizontal top flap about a horizontal axis. The semitrailer can further include a first link having a first end pivotally connected to the horizontal top flap and a second end pivotally connected to a slider, wherein the slider is connected to the door to vertically slide along a vertical axis. In a configuration, a vertical flap and horizontal top flap is hingedly connected to each door. Each vertical flap and horizontal top flap can be an aerodynamic panel formed of a material selected from the group consisting of plastic, metal, fabric, cardboard, and framed fabric.

In yet another configuration, a semitrailer includes a main frame, a wheel set connected to the main frame, the wheel set including a leading axle and a trailing axle, each of the leading axle and the trailing axle having at least two wheels for rotation relative to the main frame, and a diffuser extending about a portion of the leading axle, the diffuser extending along a majority of the distance between the wheels of leading axle, wherein the diffuser directs a passing air flow toward the ground. The diffuser can extend rearward to the trailing axel and may encompass a portion of the trailing axle. The diffuser locates a portion of the leading axle and the trailing axle between the diffuser and the main frame.

In yet another configuration, a semitrailer includes an underside, a hitch, a wheel set, a frame connected to the underside of the semitrailer intermediate the hitch and wheel set, the frame having a front portion, a back portion, a bottom portion and two opposing lateral sides, a skin enclosing at least one portion of the frame, and a back unit for mounting to a back planar surface of the semitrailer, the back unit having (i) first and second frames formed of a plurality of struts, each frame having a base portion arranged proximate the back planar surface of the semitrailer and a protruding portion of the frame arranged distal to the back planar surface of the semitrailer, wherein the base portion of the first frame circumscribes a first portion of the back planar surface of the semitrailer and wherein the base portion of the second frame circumscribes a second portion of the back planar surface of the semitrailer, and (ii) a material substantially enclosing the back unit frames. The first and second frames can each form approximately ½ of a pyramid. The back planar surface of the semitrailer can include fixed hinges and hinge bolts for receiving a first terminal end of each strut of the frame, wherein the first termination end of each strut includes a pivoting connector arranged to engage one of the hinge bolts.

In another configuration, a semitrailer comprises a main frame having a hitch, an axle assembly connected to the main frame, the axle assembly including at least two wheels for rotation relative to the main frame, a fairing connected to an underside of the semitrailer intermediate the hitch and the axle assembly, the fairing including (i) a pair of lateral surfaces, (ii) a bottom surface spaced from the underside of the semitrailer, and (ii) a leading surface. In a further configuration, the leading surface includes an intake opening, and wherein at least one of the bottom surface or the lateral surfaces includes an exit opening, and a flow path fluidly connects the intake opening and the exit opening. In one configuration, the fairing is movable relative to a main frame of the semitrailer to maintain a given spacing between the axle assembly and the fairing independent of the axle assembly being in a first position or a second position. The main frame can further includes a plurality of elongate beams extending along a longitudinal axis and a plurality of cross beams connected to the elongate beams and extending transverse to the longitudinal axis, an upper surface of the cross beams and the elongate beams supporting a decking and the decking, the elongate beams and the cross beams defining a plurality of cavities opening to an underside of the semitrailer, wherein a covering on an underside of the semitrailer substantially occludes the plurality of cavities. The covering in one configuration is connected to the elongate beams and the cross beams. A portion of the covering can be disposed between the wheels and one of the elongate beams and the cross beams, wherein the covering comprises a material selected from the group consisting of a polymer, composite, laminate, metal, and plastic.

In one configuration, the lateral surfaces are separated by a distance and the leading surface substantially spans the distance, wherein the bottom surface spans an area bounded by the lateral surfaces and the leading surface and includes an angled portion extending away from the underside of the semitrailer. In this configuration, the leading surface defines a bow having a shape selected from the group consisting of flat, curved, arched, angled, tumblehoned, plumed, raked, and spooned. The leading surface can includes first and second venting ducts extending from an intake opening in the leading surface to the exit-opening in each corresponding lateral surface, wherein air exiting the exit-openings reduces a pressure on an outside surface of the fairing and/or on at least one of (i) the bottom surface of the fairing, and (ii) the lateral surface.

In yet another configuration, the semitrailer comprises a back unit for mounting to a back planar surface of the semitrailer, the back unit having (i) first and second frames formed of a plurality of struts, each frame having a base portion arranged proximate the back planar surface of the semitrailer and a protruding portion of the frame arranged distal to the back planar surface of the semitrailer, wherein the base portion of the first frame circumscribes a first portion of the back planar surface of the semitrailer and wherein the base portion of the second frame circumscribes a second portion of the back planar surface of the semitrailer, and (ii) at least one skin substantially enclosing the first and second frames. The semitrailer in one configuration includes a closable container on the main frame, the container having a rear end and a pair of doors movable between a closed position and an open position, each door hingedly connected to the container to pivot about a vertical axis, a vertical flap, at least an upper hinge and a lower hinge hingedly connected to one of the doors and the vertical flap to pivot the vertical flap about a vertical axis, and, an interconnector extending between the upper hinge and the lower hinge, such that upon movement of the lower hinge from an open configuration to a closed configuration, the upper hinge moves from an open configuration to a closed configuration. A diffuser extends about a portion of a leading axle and a trailing axle of the axle assembly, wherein the diffuser directs a passing air flow toward the ground.

BEST MODE(S) FOR CARRYING OUT THE INVENTION

At the outset, it should be appreciated that like drawing numbers on different drawing views identify identical structural elements of the invention. While the present invention is described with respect to what is presently considered to be the preferred embodiment, it is understood that the invention is not limited to the disclosed embodiment.

Furthermore, it is understood that the invention is not limited to the particular methodology, materials, and modifications described and as such may vary. It is also understood that the terminology used herein is for the purpose of describing particular elements only, and is not intended to limit the scope of the present invention, which is limited only by the appended claims.

The drag force reduction system increases fuel economy for tractor-trailer trucks, straight trucks, cargo carriers, school buses and the like by reducing drag under the vehicle and off the back of the vehicle.

Averting now to the Figures,FIGS. 1 and 3show a fairing system100coupled to an undercarriage10of a semitrailer12. As shown inFIGS. 1-4, the semitrailer12includes a main frame14extending along a longitudinal axis16, wherein the longitudinal axis16is generally the major axis of the semitrailer12and extends along the length of the semitrailer12.

The semitrailer12can include any of the standard components known in the art including, but not limited to a coupling such as king pin, lighting, hoses, cabling or wiring. The semitrailer12can also include landing gear as known in the art. It is understood the semitrailer12can be any of the known configurations including but not limited to dump semitrailers, container semitrailers, chip van, refrigerated, log, flatbed or tank semitrailer.

The semitrailer12includes a subframe18as shown inFIG. 3movably connected to the main frame14. In one configuration, the subframe18is movably connected to the main frame14by means of a plurality of tracks20, such that the subframe18can move along the tracks20to be located at any of a number of positions along the longitudinal axis16. The use of a subframe18and interconnection to the main frame14is known in the art. Representative disclosures include U.S. Pat. Nos. 5,314,201; 5,232,234; 5,137,296 and 6,279,933, each of which is hereby expressly incorporated by reference.

The interconnection of the subframe18and the main frame14provide for the subframe18to be located at any of a multitude of positions along a range of motion, wherein the range of motion can be as long as ten (10) feet.

The subframe18carries an axle assembly30and the axle assembly30includes at least an axle32, a plurality of wheels34, and a suspension (not shown). In many configurations, the axle assembly30includes brakes, hydraulics, air lines, and connections to air ride systems as known in the art. It is understood the axle assembly30can include one, two or more axles, wherein each axle can include two or more wheels. Thus, as well known in the art, the motion of the axle assembly30relative to the main frame14locates the wheels34at correspondingly different locations along the longitudinal axis16. Thus, for example, locating the wheels34closer to a front of the main frame14allows for easier maneuverability in congested areas and tight-radius turns, such as at an intersection. In addition, selective location of the axle assembly30provides for improved load distribution.

The fairing system100further includes a fairing102located under the main frame14and spaced from the axle assembly30along the longitudinal axis16by a given distance. In select configurations, the given distance is adjustable, typically within a faring range of motion less than approximately three (3) feet. Further, the faring range of motion extends from a proximate position locating a portion of the fairing102approximately one (1) inch from the wheels34of the axle assembly30to approximately three (3) feet from the wheels34.

The fairing102produces a smooth outline and reduces drag with respect to passing airflow, such as induced when the semitrailer12is being towed by a tractor. The fairing102can extend along the longitudinal axis16from adjacent landing gear36to adjacent the wheels of the axle assembly—subject to the fairing range of motion as set forth above. It is understood the fairing102can extend along the longitudinal axis16for an little as ten percent (10%) of the distance between the wheels34and the landing gear36to one-hundred ten percent (110%) of the distance thereby encompassing the landing gear36. In one configuration, the fairing102extends along approximately half the distance between the landing gear36and the axle assembly30. Advantageously, the fairing102extends as close to the roadway as operationally possible and is at least as wide as the width of the axle assembly30. The fairing102can extend across substantially the entire width of the semitrailer or a percentage of the width. Thus, the width of the fairing102may encompass the width of the wheels34, or terminate within the spacing between the wheels34. It is further contemplated the fairing102can have lateral extensions located outside the width of the wheels34, and thus can locate at least a portion of the wheels34between the lateral extensions in select positions of the fairing102relative to the axle assembly30.

The fairing102is movable relative to the main frame14such that as the subframe18(and axle assembly30) are moved along the longitudinal axis16relative to the main frame14, the given spacing between the axle assembly30and the fairing102is maintained. That is, the position of the fairing102relative to the axle assembly30is independent of the position of the axle assembly30relative to the main frame14. As the axle assembly30is moved relative to the main frame14(thereby accommodating a different turning-radius or load distribution) the fairing102is maintained in a constant position relative to the wheels34of the axle assembly30.

It has been found that by locating a rear edge104of the fairing102as near as possible to the wheels34of the axle assembly30, the efficiency of the semitrailer12increases (or conversely the required gas consumption decreases). However, it is understood that various road conditions, loads or environmental conditions may require the spacing between the fairing102and the wheels34be adjusted within the fairing range of motion. That is, the aerodynamic efficiency of the fairing102can be dependent on the specific spacing of the fairing102and the wheels34for a given set of operating conditions. Thus, the fairing102can be mounted at any of the variety of locations along the faring range of motion relative to the axle assembly30to maximize the effectiveness of the fairing102. However, once the relative position of the fairing102relative to the axle assembly30has been temporarily fixed or selected, the fairing102and the axle assembly30translate as a unit relative to the semitrailer main frame14.

The fairing102can include a fairing frame106as shown inFIG. 3upon which is retained or disposed a covering108to form an aerodynamic shape. The aerodynamic shape of the fairing102can be any shape that reduces aerodynamic drag. The fairing frame106can define any of a variety of shapes from curvilinear surfaces, such as a dome to a point or a pyramidal shape.

As shown inFIGS. 3 and 4, the fairing102can include lighting110for safety, visibility and marketing. The lighting110can be any known in the art including LED, wherein control of the lighting can be provided by a tractor or control within the fairing. In one configuration, the lighting110is disposed along the perimeter edge of the lateral surface of the fairing.

While the fairing102is described in terms of a fairing frame106and covering108, it is understood the fairing frame106and covering108can be a substantially integral or blended in structure, such as by molding or forming, as show inFIG. 4. In this construction, the fairing102, or at least portions of the fairing102, can be formed by molding polymer. Alternatively, the fairing102can be formed of a combination of frame sections and integral (molded) sections.

The mounting or connection of the fairing102relative to the semitrailer12can be accomplished through a variety of configurations.

In one configuration, the main frame14includes at least one and can be as many as a multitude of tracks112extending along the longitudinal axis16. The fairing frame106includes a corresponding number of slides or bosses114slidably received within the tracks112such that the fairing102can move relative to the main frame14. The fairing frame106is further connected to the axle assembly30or the subframe18, such that as the axle assembly30is moved relative to the main frame14, the fairing102is correspondingly moved within the tracks112along the longitudinal axis16. This maintains the relative spacing between the fairing102and the wheels34of the axle assembly30independent of movement of the main frame14relative to the axle assembly30and/or subframe18.

In one configuration, it is contemplated the slides114of the fairing102can include setoffs or standoffs116which space a portion of the fairing frame106below the subframe18to avoid interference with the subframe18.

It is contemplated the connection of the fairing102to the axle assembly30(subframe18) is adjustable within the fairing range of motion, such as the previously disclosed one (1) inch to three (3) feet.

In a further configuration as shown inFIGS. 6A and 6B, the fairing102includes a mounting portion90and a frame retaining portion92, wherein a telescoping or slide interconnection is formed between the mounting portion90and the frame retaining portion92. The mounting portion90is configured to affix to the subframe18or axle assembly30and the frame retaining portion92is configured for supporting or defining the fairing102. The range of motion between the mounting portion90and the frame retaining portion92define the fairing range of motion—from one (1) inch to three (3) feet. The mounting portion90and frame retaining portion92can be releasably, but fixedly connected so that an operator can adjust and then trail the semitrailer12with the fairing102in a selected position relative to the wheels34(axle assembly34). In this configuration, as the fairing frame106is mounted only to the axle assembly34(or the subframe18) rather than the main frame14and there is no need for the tracks112along the underside of the main frame14.

It is contemplated the fairing102can have a substantially open rear end, a closed rear end or a partly occluded rear end. That is, the fairing102can define the air flow deflecting surface wherein the rear of the fairing (facing the axle assembly) is open forming a pocket. Alternatively, the fairing102can define a substantially enclosed volume precluding ingress or egress. In a further configuration, the fairing102can have a partially occluded rear end, such as by panels or sections inhibiting a flow into the pocket of the fairing from the rear. Depending on the specific configuration, the panels can be located at different positions along the longitudinal axis. Thus, some panels in at the rear of the fairing can be proximal to the axle assembly and other panels can be distal to the axle assembly.

As shown inFIG. 7, the fairing102can include an intake opening118and at least one flow path fluidly connecting the intake opening118and an exit-opening120. In a configuration, the flow path fluidly connecting the intake opening118and the exit-opening120is formed from at least one venting duct122. The exit-opening120can have a cross-sectional area less than or equal to a cross-sectional area of the intake opening118.

In a further configuration, as shown inFIG. 5, the disclosure provides a diffuser300for reducing air flow between spaced axles in the axle assembly30, such as a tandem. The diffuser300defines a generally curvilinear surface at least partially encompassing a diameter of at least one of a leading and a trailing axle in the axle assembly, as shown in the pictures. In one configuration, the diffuser300extends along the bottom portion of the axles. In a further configuration, the diffuser300substantially encompasses the leading and trailing axle. The diffuser can be a single piece construction or multiple piece construction, wherein the multiple pieces are assembled about the axles.

The diffuser300can include channels310extending generally along the longitudinal axis16, wherein the channels310direct air flow downward and just behind the wheels34, thereby intersecting road spray and substantially reducing the ability of the road spray to elevate from a road surface.

In a further configuration, the diffuser300can be a substantially planar member extending along the longitudinal axis16from just ahead of the leading axle to just behind the trailing axle. This configuration accommodates the construction of the tandem by the original equipment manufacturer and the occupation of the space above the leading axle and trailing axle with cabling, hoses and struts. In those constructions of the tandem in which the space above the axles is clear, the diffuser300can extend above and below the axles, thereby partially enclosing the axles. In a further configuration, the diffuser300(either as single member or multiple component) extends across a majority of a width between the wheels of the leading axle.

The diffuser300thus attaches between the axles of the axle assembly and beneath the main frame to span the distance between the axles creating an aerodynamic surface. This surface controls the air flow beneath the semitrailer12eliminating the need for a lower door mounted panel on the rear doors. The diffuser300also channels the air past a lower bumper of the semitrailer12removing the air from the drag stream and also channels a portion of the controlled air to knock down road mist during rain.

As shown inFIGS. 8 and 9, in those configurations of the semitrailer having a container with a rear end40of the container including a pair of openable doors42as known in the art, each door42can include a vertical flap400hingedly connected to the door42along an outside edge and a horizontal flap402hingedly connected along a top of the door42. The vertical flap400is movable between an extended position extending generally rearward from the rear end40of the container to a retracted position wherein the flap400is generally parallel to the door42.

In one configuration, at least a bottom hinge404and a top hinge406connect the vertical flap400to the door42, wherein the hinges404,406, are mechanically connected such that actuation of the bottom hinge404will impart actuation of the top hinge406. A rod or bar can form an interconnect between the hinges404,406for imparting common actuation.

In one configuration, the vertical flap400includes at least two attachment points to the door of the container. Each attachment includes a leaf or plate408affixed to the flap402, wherein each plate408includes a barrel410. The plate408can be any configuration as dictated by the selected material of the plate408and the flap402. In this configuration, the plate408is attached to the door42to locate the barrel410adjacent to an existing hinge connection between the container door42and the container. To install the flap402, a hinge pin412is removed from the corresponding hinge404or406on the door42and the barrel410of each of the plates408affixed to the flap402is aligned with the barrel420of the existing hinge404,406. An extended hinge pin412is then located in the existing hinge404,406and the barrel410of the affixed plate408of the flap402. The flap402is thus rotatably mounted to the container.

Referring to the drawings, a linkage414which is separate from the hinges404,406links the flap402to the door42. The linkage414includes a generally U-shape base416having a closed end of the U rotatably connected to the door42, such as by a coupler or channel bracket. Each leg of the U shape base416pivotally connects to an arm418which in turn is pivotally connected to the door42. The closed end of the U shape base416forms the rod or bar that interconnects the hinge404,406(or linkages) for imparting common actuation.

With respect to the horizontal top flaps402, these flaps402can be hingedly connected to the container door by affixing a hinge plate422to the flap402and to the door42and secured by a pin421so that the flap402is rotatable between a closed position generally parallel to the door42and an open position extending away from the door42. While the top flaps402can be selectively rotated between the open and closed positions by any of a number of mechanisms, a satisfactory mechanism includes a first link424having a first end pivotally connected to the horizontal flap402at a distance from the axis of rotation of the horizontal flap402. A second end of the first link424is pivotally connected to a slider426, wherein the slider426is connected to the door42to vertically slide along a vertical direction. In one configuration, the slider426can be pulled vertically downward with a pivoting bar actuated by pushing, causing the horizontal flap402to rotate downwards toward the container door42. Conversely, to dispose the horizontal flap402in the open position, the slider426is urged upward by pushing causing the flap402to rotate to the open position.

Thus, the system provides an aerodynamic system for the rear of the container having four movable flaps—two vertical side flaps400and two horizontal top flaps402—and an axle diffuser300, as set forth below.

Generally, the rear flaps400,402attach to the top and side of the rear end of the semitrailer, including a side flap400and top flap402for each door42. The side flaps400include an aerodynamic panel430and a mounting that uses the door hinges for swing doors and the door frame for roller doors. The aerodynamic panel material can be plastic, metal, or other semi-rigid to rigid material, including fabric in a frame. To mount the aerodynamic panels430to the door42and a deployment device, the respective flap400,402is mounted to the truck by the above described method and is deployed by moving the panel430into the open position through the use of a pivoting bar. The pivoting bar locks open and closed through the use of the above-described pin system.

In a further configuration, the present disclosure provides for streamlining the semitrailer main frame14. In this configuration, the main frame14includes two and sometimes three (or more) elongate beams extending along the longitudinal axis16, wherein a multitude of cross beams extending transverse to the elongate beans to provide a rigid frame upon which decking is attached to form the floor or deck of the semitrailer.

In this configuration, a covering502is affixed across the bottom (or exposed edge) of the crossbeams to form a substantially continuous undersurface of the semitrailer as shown inFIG. 5. It is contemplated the covering502extends over substantially the entire area of the underside of the semitrailer—even between the wheels and the bottom of the main frame. The covering502can be any of a variety of materials such as sheet metal, composites, plastics such as polycarbonate, or even tightly drawn fabrics.

The semitrailer includes a covering502that runs either longitudinally or horizontally along the bottom of the main frame covering the supporting I-Beams (transverse beams), thereby shielding the beams from the passing air flow. The covering502can be any material that is lightweight, durable, weather resistant, road debris resistant. (oil, diesel, gas, tar, mud etc.)

The covering502can be attached by any of several methods including tracks, clips, screws, bolts, flashings etc. It is contemplated the I-beam cover can extend all or a portion of the semitrailer bottom—front to back and side to side.

Referring toFIGS. 10,11, and17, in another configuration, a fairing101includes a pair of opposing lateral surfaces109and a leading surface111. The pair of opposing lateral surfaces109are separated by a distance that is substantially equal to the width of the semitrailer. The distance can vary in width depending on the semitrailer size, design, and to maximize the aerodynamic advantage of the system. By “substantially equal to the width of the semitrailer,” it is meant that the opposing lateral surfaces109are spaced inwardly from the perimeter side edge of the semitrailer10by approximately zero to twenty-four (24) inches and more preferably between zero and eight (8) inches. Alternatively, all or a portion of the lateral surfaces109can protrude approximately zero to four (4) inches from the outer perimeter side edge of the semitrailer. The leading surface111substantially spans the distance between the opposing lateral surfaces109and defines a bow113to reduce a drag coefficient of the fairing101. As shown inFIG. 15and described below, in one configuration, the bow113is formed of two integrally connected panels103,105. The panels103,105can each include an upper lip187extending forward from the bow113and a sidewall189integrally connected to a corresponding edge of the lateral surface109.

The bow113can be flat, curved, bulbous, arched, or angled, have a high or low chin, and can have any of the following shapes: tumblehome, plumb, raked, spoon, etc. Further, the bow113can be curved or bulbous in the center and substantially flat along the remaining surface. The position of the bow113on the undercarriage12of a semitrailer10can be adjusted according to the vehicle or truck type and the load type. The lateral surfaces109can be planar or can have at least one of a convex and concave portion. As shown inFIGS. 14,15and16, in one configuration, the leading surface111is formed of two flat, half-bulbous, or slightly-curved panels103,105. The leading surface111can include at least one intake opening149having a diameter range of approximately six inches to approximately four feet. In one configuration, as shown in, for example,FIG. 15, the leading surface111includes two intake openings149spaced approximately at least one foot apart from each other for a 45-53 foot semitrailer. The openings149can include a venting duct151fluidly coupling each intake opening149to either an exit-opening155in the bottom surface115as shown inFIG. 15, or an exit-opening in each of the lateral surfaces109as shown inFIG. 16. In one configuration, the exit-openings, for example exit-opening155, have a cross-sectional area that is less than a cross-sectional area of the intake opening, for example, intake opening149. In another configuration, the exit-openings have a cross-sectional area that is equal to a cross-sectional area of the intake openings. When a tractor-trailer is traveling, the air follows a flow path through intake opening(s)149in the leading surface111, through the venting duct(s)151and either out the exit-opening(s)155in the bottom surface115as shown inFIG. 15reducing pressure and drag from the bottom surface115and along the lateral surfaces109, or, out the exit-openings155in each of the lateral surfaces109, as shown inFIG. 16, reducing pressure and drag on the lateral surfaces109.

In one configuration, the bottom surface115of the fairing101is spaced from the undercarriage12of the semitrailer10and spans an area bounded by the lateral surfaces109and the leading surface111.

In another configuration, the fairing101includes a trailing surface117spaced from the undercarriage12of the semitrailer10, the trailing surface117substantially spanning the distance between the opposing lateral surfaces109. Back panel191is shown in phantom so that trailing surface117can be seen. The trailing surface117is spaced from the wheel set and lowers the drag coefficient of the fairing assembly101. The trailing surface117extends from a spaced position from the underside of the semitrailer10to a position adjacent the underside of the semitrailer10, and intermediate the wheel set and the first position119such that the trailing surface117is angled. The second position121of the trailing surface117can be between one (1) inch and eighteen (18) inches from the underside of the semitrailer10and more preferably between two (2) and nine (9) inches. The bottom surface115and the trailing surface117substantially enclose a volume beneath the semitrailer10. By “substantially encloses” it is meant that at least seventy percent (70%) of the undercarriage between the hitch and wheel set is enclosed by the fairing assembly101.

In another configuration, as shown inFIG. 11, the drag force reduction system197includes a frame211connected to the undercarriage12of a semitrailer10and a skin201enclosing at least one portion of the frame211. The frame211is sized to be intermediate the hitch and wheel set of a semitrailer10. The position of the frame211on the underside of the semitrailer10can be adjusted according to the vehicle or truck type and the load type.

The frame211includes a front portion203, a back portion205, a bottom portion207and two opposing side portions209formed by sets of struts. In one embodiment, the struts are metal, plastic or PVC. The side portions209are spaced at a distance that is substantially equal to the width of the semitrailer. The back portion205is spaced from the wheel set of the semitrailer10and includes a top edge213. In one configuration, the top edge213is spaced from the undercarriage of the semitrailer10. For example, the back portion205can be spaced between two and nine inches from the undercarriage12of the semitrailer10. Preferably, the space is approximately six inches. The back portion205of the frame211extends at an obtuse angle relative to the bottom portion207.

The frame211can have interconnecting modular sections. Preferably, the modular sections are approximately 1 foot to 20 feet wide. More preferably, the modular portions are approximately 2 feet to 10 feet wide. The side portions209can be planar or can have at least one of a convex and concave portion. The frame211can further comprise aerodynamic fin portions215extending from the side portions209of the frame211.

The skin201encloses at least one portion of the frame211reducing a drag coefficient of the system. In one configuration, the skin201substantially encloses the front portion203, the side portions209and the bottom portion207of the frame211. In another configuration, the skin201substantially encloses the back portion205of the frame211. The skin201can be made from one or more than one of the following: polycarbonate, ABS plastic, metal, rubber, fabric and polyurethane.

In a configuration of the invention, the frame211is modular and can be used as a storage system, wherein any singular modular portion201is enclosed and includes a resealable access port (not shown) or wherein multiple modular portions are enclosed to form one storage area which includes a resealable access port (not shown).

The front portion203may include at least one intake opening249. In one configuration, the front portion203includes two intake openings249spaced at least approximately 1 foot apart from each other on a 45-53 foot semitrailer. The openings249may include a venting duct251fluidly coupling each intake opening249to either an exit-opening in the bottom portion207or an exit-opening255in each of the opposing side portions209. When a tractor-trailer is traveling, the air follows a flow path through intake opening(s)249in the front portion203, through the venting duct(s)251and either out the exit-opening(s)255in the bottom portion207reducing pressure and drag from the bottom portion207and along the side portions209or out the exit-openings255in each of the side portions209reducing pressure and drag on the side portions209.

As shown inFIGS. 10,12, and13, the drag reduction system may include a back unit299for mounting to a back planar surface of the semitrailer10. The back unit299includes either one frame301or two half-frames (also referred to herein as first and second frames)303that together circumscribe a back planar surface of the semitrailer10. The frame301or half-frames303are formed of a plurality of struts305and include a base portion307. In the one frame configuration, the frame301is approximately pyramidal. In the one frame301configuration, the frame301includes a base portion307arranged proximate the back planar surface of the semitrailer10and a protruding portion309arranged distal to the back planar surface of the semitrailer10. The first and second frames303can each form approximately ½ of a pyramid. The base portion307of the one of the half-frames301circumscribes approximately half of the back planar surface of the semitrailer and the base portion of the second frame circumscribes approximately the other half of the back planar surface of the semitrailer10. In this configuration, each half-frame303includes a center post319and a guide lock for locking the half-frame303on to the rear-end of the semitrailer10during installation and for releasing the guide lock upon removal of each half-frame303.

A material311substantially encloses the back unit frames301or303. To secure the back unit to the semitrailer10, hinges313are fixed to the back planar surface of the semitrailer10as well as hinge bolts for receiving a first terminal end317of each strut305. One end of each strut305includes a pivoting connector arranged to engage one of the hinge bolts. It should be appreciated by those having ordinary skill in the art that other connectors and anchors can be used to secure the back unit to the semitrailer, including but not limited to anchors, swivel joints, connectors, and vertical anchors.

Preferably, the material311is flexible and pulled taut around the frame301. Although the material311is set forth as enclosing the frame301, it is understood the material311can be connected to the frame301to be within the volume defined by the frame301. However, such construction requires more fasteners connecting the material311to the frame301.

As shown inFIG. 10, the fairing185may also include a plurality of lighting elements129(also referred to herein as lights) disposed along the lateral surfaces109or a portion thereof. In one configuration, the lights129are disposed along the perimeter edge131of the lateral surfaces109. It should be appreciated that by illuminating the lateral surfaces109of the fairing185, road safety is improved by making the trailer portion of the tractor-trailer181more visible. Further, the lights129can be used to illuminate the lateral surfaces109and/or panels133having marketing indicia, logos or other advertising features.