Patent Description:
Trailers towed by trucks and similar apparatuses for transporting cargo can be large, unwieldy, and include geometries which invite inefficiencies during travel. One aspect of these inefficiencies concerns the aerodynamics of the trailer. For maximum capacity, the trailer is box shaped which is not the most aerodynamically available option. Further, the rear door of the trailer is made in a particular manner to facilitate loading and unloading, such as utilizing a large opening, and the rear door may not have optimal aerodynamic properties. In an effort to improve trailer aerodynamics, trailers have been built, supplemented, or retrofitted with trailer skirts (or side skirts), devices affixed to the underside which limit air circulating in the empty space between the trailer's axles. By reducing the amount of airflow in this space, drag caused by turbulence is reduced and permits the trailer to be towed more efficiently, increasing the gas mileage and performance of the vehicle and its cargo. Other ways of improving aerodynamic performance of the trailer involves the provision of fairings to the end of the trailer. The fairings modify the airflow around or off of the end of the trailer to reduce drag. It is known to produce fairings that extend a good bit (<NUM> (<NUM> inches) or more) off the back end of the trailer for the purposes of reducing drag. Boat tails are devices arranged at the back end of the trailer to help converge and stabilize the wake at the back of the trailer for improved aerodynamic performance.

Combining all of these various aerodynamic elements is problematic because the local aerodynamics of the vehicle are impacted by the geometry of the entire vehicle. Some devices may improve performance when used by themselves, but have no impact on performance when used with other devices. This may be because a particular component is designed to maximize its individual contribution to fuel savings, and is not designed to work together optimally with other components in the system. Aerodynamic components of a trailer that include moving parts will require maintenance, and drivers may be required to remember to deploy some other types of aerodynamic devices. Also, the placement of various devises far off the back end of the trailer adds to the length of the trailer increasing the risk of damage to these components and surrounding vehicles. It would be desirable to have an aerodynamic system that incorporates a trailer end fairing and other components in an optimal manner for purposes of increasing the aerodynamic performance of the trailer. As such, there remains room for variation and improvement within the art.

In view of the above problems, the present invention provides a trailer with a bogie according to independent claim <NUM>. The dependent claims relate to advantageous embodiments.

The use of identical or similar reference numerals in different figures denotes identical or similar features.

Reference will now be made in detail to embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, and not meant as a limitation of the invention. For example, features illustrated or described as part of one embodiment can be used with another embodiment to yield still a third embodiment. It is intended that the present invention include these and other modifications and variations, as long as they fall under the scope of the appended claims.

The present invention provides for an apparatus <NUM> that achieves aerodynamic performance of a trailer <NUM> when driven by a tractor <NUM>. The apparatus <NUM> includes a top fairing <NUM>, a first side fairing <NUM>, and a second side fairing <NUM> located at the back of the trailer <NUM>. The side fairings <NUM>, <NUM> may or may not engage the top fairing <NUM> such that a gap may or may not be present between them and a continuous surface may or may not extend from the side fairings <NUM>, <NUM> onto the top fairing <NUM>. In other words, the top fairing <NUM> could in some instances connect to both of the side fairings <NUM>, <NUM> to form a continuous surface at the back section of the trailer <NUM>, and in other instances gaps could be present between the side fairings <NUM>, <NUM> and the top fairing <NUM>. The apparatus <NUM> also includes first and second trailer skirts <NUM>, <NUM> in addition to the top fairing <NUM> and side fairings <NUM>, <NUM> to further enhance aerodynamic performance. Yet further, the apparatus <NUM> includes trailer rear skirts <NUM>, <NUM> to achieve airflow properties upon normal use of the tractor <NUM> trailer <NUM>. Additional features can be incorporated into the system the apparatus <NUM> comprises as will be discussed in order to achieve different aerodynamic properties of the trailer <NUM>.

The fairings consist of a half airfoil attached or touching the top and/or side of the trailer. Extending away from the flat plane of the side or top of the trailer then curving towards the side or top panel. They are between <NUM>,<NUM> and <NUM>, <NUM> (<NUM>" and <NUM>") at their thickest part, and may or may not extend off the back of the trailer. They should end at the rear edge of the trailer or extend off the back by up to <NUM> (<NUM>") and preferably less than <NUM>,<NUM> (<NUM>"). Preferred lengths from front to back are approximately <NUM> to <NUM><NUM><NUM> , <NUM> (<NUM>" to <NUM>") long. These fairings are configured such that airflow flows over the outer surface. This means that there is only one functional surface instead of previous inventions which show a wing that has airflow both over and under functional surfaces.

<FIG> show a tractor <NUM> with attached trailer <NUM> on the ground <NUM> according to an illustrative example not falling under the scope of the claims. In normal use, the tractor <NUM> is driven forward in the longitudinal direction <NUM> and aerodynamic features of the system are designed to handle this forward motion. Cross flow of air will be imparted onto the trailer <NUM> in the lateral direction <NUM> and the apparatus <NUM> may include features addressed to this cross-flow. The first side fairing <NUM> is located at the back of the trailer <NUM> in the longitudinal direction <NUM> and is mounted onto or over the first side surface <NUM> of the trailer <NUM>. In a similar manner, the second side fairing <NUM> is mounted on or over the second side surface <NUM> of the trailer <NUM>. The top fairing <NUM> is mounted on or over a portion of the top surface <NUM> of the trailer <NUM>. The fairings <NUM>, <NUM>, <NUM> are located closer to the back end <NUM> of the trailer <NUM> in the longitudinal direction <NUM> than to the front of the trailer <NUM>. In some instances, the fairings <NUM>, <NUM>, <NUM> could extend to the back end <NUM> of the trailer <NUM>, and in yet other configurations one or more of the fairings <NUM>, <NUM>, <NUM> could extend rearward of the back end <NUM> of the trailer <NUM> up to <NUM> inches in the longitudinal direction <NUM>. The upper surfaces of the fairings <NUM>, <NUM>, <NUM> may have flat, angled, or curved sections so that airflow over them will achieve certain aerodynamic performance when the trailer <NUM> is driven. The top fairing <NUM> extends across the entire width of the top surface <NUM> in the lateral direction <NUM>, but the side fairings <NUM>, <NUM> extend along a majority of the height of the side surfaces <NUM>, <NUM> in the vertical direction <NUM> but not along the entire height of the side surfaces <NUM>, <NUM> in the vertical direction <NUM>. In some instances, the fairings <NUM>, <NUM> extend from <NUM>/<NUM> to <NUM>/<NUM> of the heights of the side surfaces <NUM>, <NUM> in the vertical direction <NUM>. This amount of coverage can be measured downward in the vertical direction <NUM> starting from the top surface <NUM>. The fairings <NUM>, <NUM>, <NUM> are structures that can be curved panels that attach at a leading edge to the top surface <NUM> and side surfaces <NUM>, <NUM> in such a way that the fairings <NUM>, <NUM>, <NUM> curve or otherwise extend away from the surface <NUM>, <NUM>, <NUM> in question and then curve or otherwise extend back to the surface <NUM>, <NUM>, <NUM> in question. This extension away from and then back to can be viewed in the forward to rearward direction in the longitudinal direction <NUM>.

The side fairings <NUM>, <NUM> engage the top fairing <NUM>. This engagement may be along the entire lengths of the side fairings <NUM>, <NUM> in the longitudinal direction <NUM> or may be less than along their entire lengths. There could be gaps in the engagement of the side fairings <NUM>, <NUM> to the top fairing <NUM> along a portion of their lengths in some instances. Further, there could be cases where one or two of the fairings <NUM>, <NUM>, <NUM> are longer than the other one or two and in these instances there would be longitudinal sections that are not in engagement. Further, additional designs exist in which one of the two side fairings <NUM>, <NUM> does not engage the top fairing <NUM> at all, but the other one of the two side fairings <NUM>, <NUM> does in fact engage the top fairing <NUM>. The engagement between the side fairings <NUM>, <NUM> and the top fairing <NUM> may be form a <NUM> degree bend, or there could be convex surfaces between these components <NUM>, <NUM>, <NUM> that achieve a smoother transition at their engagement locations, or a combination of various geometric designs can be present at the points of engagement. Engagement of the top fairing <NUM> with at least one of the side fairings <NUM>, <NUM> achieves a desired aerodynamic performance of the trailer <NUM> during normal use. The fairings <NUM>, <NUM>, <NUM> can be mounted onto the surfaces <NUM>, <NUM>, <NUM> through the use of screws, bolts, adhesives, mechanical fasteners or even through integral formation in some instances and may or may not engage the surfaces <NUM>, <NUM>, <NUM>.

Trailer skirts <NUM>, <NUM> are part of the apparatus <NUM> and work with the fairings <NUM>, <NUM>, <NUM> in achieving aerodynamic performance of the trailer <NUM>. It has been discovered that the apparatus <NUM> having the fairings <NUM>, <NUM>, <NUM> work particularly well with the addition of the trailer skirts <NUM>, <NUM> to the apparatus <NUM>. The trailer skirts <NUM>, <NUM> are located rearward of drive tires <NUM> of the tractor <NUM> in the longitudinal direction <NUM> and are located at the bottom of the trailer <NUM> and function to direct airflow at least partially from the bogie assembly <NUM> of the trailer <NUM>. The trailer skirts <NUM>, <NUM> are panels that have surfaces that can be variously shaped that direct airflow accordingly. The panels of the trailer skirts <NUM>, <NUM> in <FIG> are parallel to the side surfaces <NUM>, <NUM> of the trailer <NUM>. In this regard, the trailer skirt <NUM> is closer to side surface <NUM> than to side surface <NUM> and is parallel to side surface <NUM>. In a similar vein, trailer skirt <NUM> is closer to side surface <NUM> than to side surface <NUM> and is parallel thereto. The trailer skirts <NUM>, <NUM> are located completely rearward of the drive tires <NUM> and completely forward of the bogie assembly <NUM> in the longitudinal direction <NUM>. However, in other embodiments, a portion of the trailer skirts <NUM>, <NUM> could extend to the bogie assembly <NUM> so that they are not completely forward of the bogie assembly <NUM>. The trailer skirts <NUM>, <NUM> can be connected or held onto the trailer <NUM> by any mechanism. For example, brackets <NUM> are present to bolt the trailer skirts <NUM>, <NUM> onto the underside of the trailer <NUM>.

The first trailer skirt <NUM> has a rearward most point <NUM> in the longitudinal direction <NUM> for redirecting airflow. Further, the first trailer skirt <NUM> has a forward most point <NUM> for redirecting airflow in the longitudinal direction <NUM>. In evaluating the parallel nature of the first trailer skirt <NUM> to the first side surface <NUM>, a first line <NUM> is drawn from the rearward most point <NUM> to the forward most point <NUM>. The first side surface <NUM> is parallel to the longitudinal direction <NUM> in that the trailer <NUM> is box shaped and extends effectively in the longitudinal direction <NUM> regardless of whether the side surfaces <NUM>, <NUM> are completely flat or have grooves or other features thereon. One can compare the angle the first line <NUM> makes to the line the first side surface <NUM> forms when viewed in the top view of <FIG> and ascertain that these two lines <NUM>, <NUM> are parallel.

The second trailer skirt <NUM> has a rearward most point <NUM> that is the part of this component located most rearward in the longitudinal direction <NUM> that functions to redirect air. Likewise, the second trailer skirt <NUM> has a forward most point <NUM> for directing airflow in the longitudinal direction <NUM>. A second line <NUM> can be drawn from the rearward most point <NUM> to the forward most point <NUM>. The line that the second side surface <NUM> makes when viewed from the top in <FIG> is observed to be parallel to the second line <NUM>. In this manner, the first and second trailer skirts <NUM>, <NUM> can be said to be arranged in a parallel manner to the first and second side surfaces <NUM> and <NUM> and the panels that direct airflow are flat with no change in angular orientation. Although the two trailer skirts <NUM>, <NUM> are arranged in a similar manner to one another, it is to be understood that in other versions of the apparatus <NUM> that one of the trailer skirts <NUM> could for instance be parallel to its side surface <NUM> while the other trailer skirt <NUM> is not parallel to its side surface <NUM>.

Another configuration of the trailer skirts <NUM>, <NUM> are illustrated in <FIG> in which a pair of skirts <NUM>, <NUM> are again present and are located completely between the drive tires <NUM> and the bogie assembly <NUM> in the longitudinal direction <NUM>. The panels making up the skirts <NUM>, <NUM> are again flat along their entire lengths. The first trailer skirt <NUM> has a rearward most point <NUM> and a forward most point <NUM> with the first line <NUM> drawn between and connecting these points <NUM>, <NUM> that matches the panel that directs airflow of the first trailer skirt <NUM>. However, the first line <NUM> is not parallel to the line of the first side surface <NUM> as seen in the top view of <FIG>. Instead, the first line <NUM> is oriented at an angle <NUM> to the first side surface <NUM>. The angle <NUM> is <NUM> degrees. In other embodiments, the angle <NUM> may be from <NUM> degrees (parallel) up to and including <NUM> degrees. The angle <NUM> is measured in the direction of extension of the trailer skirt <NUM> forward in the longitudinal direction <NUM>. The angle <NUM> is the angle of the panel of the first trailer skirt <NUM> that directs air to the first side surface <NUM> because this panel is the same as and overlaps the first line <NUM>. As such, the first line <NUM> is measured in relation to the line created by the top view of the first side surface <NUM> and the angle <NUM> between these two lines is measured. Placement of the angle <NUM> in the <NUM>-<NUM> degree range allows for complimentary aerodynamic performance of the skirt <NUM> used in combinations with the side fairings <NUM>, <NUM>, <NUM>, <NUM>. In some embodiments, the forward most point <NUM> can sit from <NUM> to <NUM> (<NUM> to <NUM> inches) inboard of the first side surface <NUM> in the lateral direction <NUM> towards the center of the trailer <NUM>. The rearward most point <NUM> could sit from <NUM> to <NUM>,<NUM> (<NUM> to <NUM> inches) inboard of the first side surface <NUM> in the lateral direction <NUM>.

The second trailer skirt <NUM> has a second line <NUM> that is oriented at an angle <NUM> to the line of the second side surface <NUM> when viewed from the top in <FIG>. This angle <NUM> is <NUM> degrees. In other embodiments, the angle <NUM> may be from <NUM> (parallel) to <NUM> degrees. The angle <NUM> can be the same as angle <NUM>, or these angles <NUM>, <NUM> can be different from one another in relation to the trailer <NUM> so that the skirts <NUM>, <NUM> are not oriented at the same magnitude of angularity to their respective side surfaces <NUM>, <NUM>. The angle <NUM> is again measured by looking at the direction of extension of the second trailer skirt <NUM> forward in the longitudinal direction <NUM>. The direction of extension of the second line <NUM> is noted upon moving forward in the longitudinal direction <NUM> from the rearward most point <NUM> to the forward most point <NUM>. This second line <NUM> is compared to the line created by the second side surface <NUM> upon viewing it from above in <FIG> and the angle <NUM> is measured as the orientation between these two lines. The skirts <NUM>, <NUM> are arranged so that they extend constantly inboard in the lateral direction <NUM> upon extension forward in the longitudinal direction <NUM>. In this regard, at no point do the skirts <NUM>, <NUM> extend outboard in the lateral direction <NUM>, but instead only in the inboard direction as observed in the forward longitudinal direction <NUM>. The forward most point <NUM> can sit from <NUM> to <NUM> inches inboard of the second side surface <NUM> in the lateral direction, and the rearward most point <NUM> may sit from <NUM> to <NUM> inches inboard of the second side surface <NUM>.

Another version of the first and second trailer skirts <NUM>, <NUM> is shown in <FIG>. Unlike previous versions, the panels that make up the trailer skirts <NUM>, <NUM> do not have flat surfaces across their entire lengths that direct the airflow. Instead, the skirts <NUM>, <NUM> have sections that are oriented at different angles to one another and at different angles to the trailer <NUM>. Although four such sections that change the angular orientation of the skirts <NUM>, <NUM> are shown, fewer or more may be present. However, the panels that direct airflow still have a rearward most point <NUM>, <NUM> and a forward most point <NUM>, <NUM>. The first and second lines <NUM>, <NUM> are drawn through these points <NUM>, <NUM>, <NUM>, <NUM> as previously discussed and the angles <NUM>, <NUM> are calculated also as previously discussed. The panels making up the airflow surfaces of the skirts <NUM>, <NUM> do not lie completely on these lines <NUM>, <NUM> as in other embodiments but are for the most part out of sync with the lines <NUM>, <NUM>. A majority may be inboard of the lines <NUM>, <NUM> in the lateral direction <NUM> in some embodiments, and in other embodiments a majority may be outboard of the lines <NUM>, <NUM>. As with other embodiments, the surfaces that direct airflow need not be flat, but could be curved and could have grooves or other features. The skirts <NUM>, <NUM> could change their direction of orientation so that they are moving either inboard or outboard in the lateral direction <NUM> at different points. However, the lines <NUM>, <NUM> still have a single angle <NUM>, <NUM> for measurement even if localized portions of the skirts <NUM>, <NUM> are oriented at different angles from one another and from that of the lines <NUM>, <NUM>.

<FIG> shows a back view of the trailer <NUM> according to an embodiment of the invention with attached apparatus <NUM>. The top fairing <NUM> has an upper terminal point <NUM> that is the highest point of the top fairing <NUM> in the vertical direction <NUM>. There may be a single upper terminal point <NUM> on the top fairing14, or there may be multiple locations where the upper terminal point <NUM> is located. The height <NUM> of the top fairing <NUM> is measured from the top surface <NUM> of the trailer <NUM>, at the same location at the upper terminal point <NUM> in the lateral direction <NUM>, to the upper terminal point <NUM> in the vertical direction <NUM>. The top surface <NUM> is a panel that covers the cargo area of the trailer. The top surface <NUM> near the back end <NUM> may have a rain gutter located thereon which would be an indentation on the top surface <NUM> that extends downward in the vertical direction <NUM>. Other structural elements could be present at or on the top surface <NUM> near the back end. When describing the heights of the top fairings <NUM> and discussion of the associated top surfaces <NUM>, it is to be understood that the heights are measured from the panel section of the top surface <NUM> and not from the rain gutters or other structural elements at or on the top surface <NUM>. The side fairing <NUM> has an outer terminal point <NUM> located on its outer surface which is the portion of the side faring <NUM> farthest from the center of the trailer <NUM> in the lateral direction <NUM>. There may be a single point on the outer surface of the side fairing <NUM> that is farthest and thus a single outer terminal point <NUM>, or there may be multiple locations along the side fairing <NUM> that are farthest and thus a plurality of outer terminal points <NUM> are present. The width <NUM> of the side fairing <NUM> may be measured from the side surface <NUM>, that is as the same vertical location as the outer terminal point <NUM> in the vertical direction <NUM>, to the outer terminal point <NUM> in the lateral direction <NUM>. The magnitude of the height <NUM> is greater than the magnitude of the width <NUM> in accordance with some exemplary embodiments. In a similar vein, the second side fairing <NUM> has a width <NUM> that is measured from the second side surface <NUM>, that is at the same location in the vertical direction <NUM>, to an outer terminal point <NUM> in the lateral direction <NUM>. The outer terminal point <NUM> is the point of the outer surface of the second side fairing <NUM> that is farthest from the center of the trailer <NUM> in the lateral direction <NUM>. The magnitude of the width <NUM> is less than the magnitude of the height <NUM> in accordance with some exemplary embodiments. In some instances, the magnitudes of the widths <NUM> and <NUM> are the same.

<FIG> shows an alternate embodiment of the invention in which the trailer <NUM> does not have flat side surfaces <NUM>, <NUM> or a flat top surface <NUM> at least at locations onto which the apparatus <NUM> is mounted. The surfaces <NUM>, <NUM>, <NUM> could be grooved or have different areas of height/width. The area <NUM> of the top surface <NUM> engaged or covered by the top fairing <NUM> has a width <NUM> that extends in the lateral direction <NUM>. The top fairing <NUM> extends into the grooves present on the top surface <NUM> so as to fill them in, but in other arrangements the grooves could be completely or partially empty. A highest location <NUM> of the top surface <NUM> is the location of the top surface <NUM> that is highest in the vertical direction <NUM>. There may be a single highest location <NUM>, or there may be multiple highest locations <NUM> along the width <NUM> of the area <NUM>. The height <NUM> is measured from the highest location <NUM> to the upper terminal point <NUM> of the outer surface of the fairing <NUM> in the vertical direction <NUM>. The side fairing <NUM> can be arranged in a similar manner in which an area <NUM> of the first side surface <NUM> has different inboard and outboard locations in the lateral direction <NUM> along an entire height <NUM> of the area <NUM>. The entire height <NUM> is the height in the vertical direction <NUM> that the side fairing <NUM> engages or covers when the apparatus <NUM> is attached. One or more locations of the side surface <NUM> can have a maximum outboard location <NUM> in the lateral direction <NUM>, and a most outboard location <NUM> is located on these one or more points of the side surface <NUM>. In <FIG>, the most outboard location <NUM> also has the same positioning in the vertical direction <NUM>. The width <NUM> is measured from the most outboard location <NUM> to the outer terminal point <NUM> in the lateral direction <NUM>. The magnitude of the height <NUM> may be greater than the magnitude of the width <NUM>.

Also, the second side faring <NUM> can have a second side surface <NUM> that is not flat but instead features grooves or other depressions cut therein. The second side fairing <NUM> may cover or be inserted into some or all of the grooves on the second side surface <NUM> and includes an outer terminal point <NUM> which is the point of the second side faring <NUM> that is farthest from the center of the trailer <NUM> in the lateral direction <NUM>. There may be a single outer terminal point <NUM>, or multiple locations of the second side fairing <NUM> may include an outer terminal point <NUM>. In a similar manner, the second side surface <NUM> may have a single or a plurality of maximum outboard locations <NUM> which are the portions of the second side surface <NUM> farthest from the center of the trailer <NUM> in the lateral direction <NUM>. The outer terminal point <NUM> and the maximum outboard location <NUM> are at the same height in the vertical direction <NUM>. The width <NUM> is measured from the outer terminal point <NUM> to the maximum outboard location <NUM> in the lateral direction. The magnitude of the width <NUM> is less than the magnitude of the height <NUM>. In some instances, the magnitude of the width <NUM> is the same as the magnitude of the width <NUM>.

An additional feature of the apparatus <NUM> is shown with reference to <FIG> in which a first trailer rear skirt <NUM> and a second trailer rear skirt <NUM> are present on the underside of the trailer <NUM>. The rear skirts <NUM>, <NUM> have panels that direct airflow to achieve a desired aerodynamic performance of the trailer <NUM> when driven. The rear skirts <NUM>, <NUM> can work in combination with the first and second trailer skirts <NUM>. The trailer rear skirts <NUM>, <NUM> are located rearward of the first and second trailer skirts <NUM>, <NUM> in the longitudinal direction <NUM> and in some instances may be located completely rearward of the bogie assembly <NUM> in the longitudinal direction <NUM>. In some embodiments, there may be a gap of at least <NUM> meters between the rearward most points <NUM>, <NUM> of the forward skirts <NUM>, <NUM> and the forward most points of the first and second trailer rear skirts <NUM>, <NUM> in the longitudinal direction <NUM>. This gap between the forward skirts <NUM>, <NUM> and the rearward skirts <NUM>, <NUM> allow for access to the bogie assembly <NUM> tires and wheels and rear axle. The gap avoids interference with the bogie assembly <NUM>, which can slide from a front location to a rear location in the longitudinal direction <NUM>, when the bogie assembly is located in one of the forward locations and running to close to the back end <NUM>.

In other instances, the trailer rear skirts <NUM>, <NUM> are not completely behind the bogie assembly <NUM> but instead at least partially cover the bogie assembly <NUM> so that at least a portion of the bogie assembly <NUM> is located at the same position in the longitudinal direction <NUM> as portions of the first and second trailer rear skirts <NUM>, <NUM>. However, regardless of the positioning of the trailer rear skirts <NUM>, <NUM> it may be the case that enough space is provided for accessing the bogie assembly <NUM> to allow for tire and wheel change when the bogie assembly <NUM> is located in the correct position. The bogie assembly <NUM> may be capable of sliding forward and rearward in the longitudinal direction <NUM> so this may effect relative placement between these components <NUM>, <NUM> and <NUM> as well. Also, providing enough access to the bogie assembly <NUM> due to the presence of the when rear skirts <NUM>, <NUM> may require one to take into account the positioning of the forward trailer skirts <NUM>, <NUM> as well.

The trailer rear skirts <NUM>, <NUM> may not extend to the back end <NUM> of the trailer <NUM> in the longitudinal direction <NUM>. Instead, the trailer rear skirts <NUM>, <NUM> can stop short of the back end <NUM> up to <NUM> meters from the back end <NUM> in the longitudinal direction so that a space no more than <NUM> meters exists from the back end <NUM> to the rearward longitudinal points of the first and second trailer rear skirts <NUM>, <NUM> in the longitudinal direction <NUM>. Of course, in other embodiments the trailer rear skirts <NUM>, <NUM> can extend all the way to the back end <NUM> in the longitudinal direction <NUM> or to any extent short of or beyond the back end <NUM>. The trailer rear skirts <NUM>, <NUM> may be attached to the bottom of the trailer <NUM> via brackets <NUM> and can extend in the vertical direction <NUM> towards the ground <NUM> stopping short to allow sufficient clearance thereto. The illustrative examples not falling under the scope of the claims in <FIG> all have <NUM> trailer rear skirts <NUM>, <NUM> but a single one of the trailer rear skirts <NUM> or <NUM> could be present in other embodiments. In still further versions, the first trailer rear skirt <NUM> is configured differently than the second trailer rear skirt <NUM>. The panels that make up the trailer rear skirts <NUM>, <NUM> could be configured in the same manners as previously discussed with respect to the forward trailer skirts <NUM>, <NUM> (for example the air directing panels are parallel to the first and second side surfaces <NUM>, <NUM>) and a repeat of this information is not necessary. In some instances, there may be a small angle associated with the trailer rear skirts <NUM>, <NUM>. This small angle may be an inward displacement at the rear <NUM>/<NUM> of the trailer rear skirts <NUM>, <NUM> in the longitudinal direction <NUM>. The amount of the displacement can be less than <NUM>,<NUM> (<NUM> inches) inboard in the lateral direction <NUM>. In other embodiments, the rear <NUM>/<NUM> is displaced <NUM>,<NUM> (<NUM> inches) inboard from the side surfaces <NUM>, <NUM> in the lateral direction <NUM>. With respect to lateral placement of the trailer rear skirts <NUM>, <NUM>, they may be positioned no more than <NUM> , <NUM> (<NUM> inches); inside of their respective side surfaces <NUM>, <NUM> in the lateral direction <NUM>. In configurations, the panels of the trailer rear skirts <NUM>, <NUM> or portions thereof sit outside of the side surfaces <NUM>, <NUM> by up to <NUM>,<NUM> (<NUM> inches) In some configurations, the trailer rear skirts <NUM>, <NUM> are parallel allowing for variation in from the side surfaces <NUM>, <NUM> by <NUM> inches for the front <NUM>/<NUM> of the skirts <NUM>, <NUM> in the longitudinal direction <NUM>, and <NUM> inches from the side surfaces <NUM>, <NUM> at the back edges of the skirts <NUM>, <NUM> in the longitudinal direction <NUM>. The lower extent of the trailer <NUM> can be tapered up to reduce the changes of impact with the ground <NUM> caused by the departure angle.

With reference back to <FIG>, the intersection of the top fairing <NUM> with the side fairings <NUM>, <NUM> includes two sharp <NUM> degree corners <NUM> at their intersection. In some embodiments, the corner <NUM> can be rounded and configured to adjust aerodynamic performance. A rounded corner <NUM> may achieve desired aerodynamic performance in relation to cross-winds imparted onto the trailer <NUM> through normal, forward use of the trailer <NUM> in the longitudinal direction <NUM>. This reduction in drag from cross-winds may increase the fuel efficiency of the tractor <NUM> trailer <NUM> vehicle. <FIG> shows the corners <NUM> at the fairing <NUM>, <NUM>, <NUM> intersections being rounded instead of having a sharp edge. Both corners <NUM> can be configured to have the same size, shape, and features, or they may be different in different embodiments, especially when the first side fairing <NUM> is not the same as the second side fairing <NUM>. The corners <NUM> can be described as being portions of the side fairings <NUM> and <NUM>, can be portions of the top fairing <NUM>, can be portions of all of the fairings <NUM>, <NUM>, <NUM>, or may be separate components from the fairings <NUM>, <NUM> and <NUM>. However, the corner <NUM> should be configured so that at least some portion of the intersection of the top fairing <NUM> and the side faring <NUM> (and <NUM> in some embodiments) is continuous. The entire intersection between the fairings <NUM>, <NUM>, <NUM> need not be continuous in other versions.

<FIG> is a perspective view of a corner <NUM> that is present on the right hand side of the trailer <NUM> according to an embodiment of the invention and is at the intersection of the second side fairing <NUM> and the top fairing <NUM>. The corner <NUM> of <FIG> could be the one shown in the <FIG> embodiment, or the one shown in other presently disclosed embodiments. The corner <NUM> at the left hand side of the trailer <NUM> which is at the intersection of the top fairing <NUM> and the first side fairing <NUM> could be made in a similar manner and a repeat of this information is not necessary. In <FIG>, the leading section <NUM> of the corner <NUM> is located at the forward most point of the corner <NUM> in the longitudinal direction <NUM>. The tailing section <NUM> of the corner <NUM> in the longitudinal direction <NUM> is located at the rearward most position of the corner <NUM>. In between these sections <NUM>, <NUM> the middle section <NUM> of the corner <NUM> is located in the longitudinal direction <NUM>. The corner <NUM> has a convex outer surface at all points from the leading section <NUM> to the tailing section <NUM>. However, in other embodiments some portion of the corner <NUM> need not be convex but could be flat, angled, or concave in shape. The shape of the corner <NUM> is driven by the size and shape of the meeting fairing <NUM>, <NUM> surfaces that converge at the corner <NUM>. The radius of curvature of the surface at the leading section <NUM> may be the same as the radius of curvature of the surface at the tailing section <NUM>, and these two radii of curvature may each be less than the radius of curvature of the surface of the corner <NUM> at the middle section <NUM>. In some instances, the radius of curvature at the leading section <NUM> is <NUM>,<NUM> (<NUM> inches), the radius of curvature at the middle section is <NUM> (<NUM> inches), and the radius of curvature at the tailing section <NUM> is <NUM>,<NUM> (<NUM> inches).

<FIG> illustrate another illustrative example of the apparatus <NUM>. In this instance, the side fairings <NUM>, <NUM> do not contact or otherwise engage the top fairing <NUM>. The first side fairing <NUM> extends upwards along the majority of the height of the first side surface <NUM> but stops short of extending to the top surface <NUM> in the height direction <NUM> so that a gap exists between the side fairing <NUM> and the top fairing <NUM> causing these components not to engage one another. The second side fairing <NUM> is arranged in a similar manner in which it extends over a majority of the height of the second side surface <NUM> but not all the way up to the top surface <NUM> thus leaving a gap between the second side fairing <NUM> and the top fairing <NUM> causing these components not to engage one another. The apparatus <NUM> further includes the first and second trailer skirts <NUM>, <NUM> and the first trailer rear skirt <NUM> and second trailer rear skirt <NUM>.

Another embodiment of the apparatus <NUM> is shown in <FIG> in which the side fairings <NUM>, <NUM> are again separate from and not contacting the top fairing <NUM>. Further, the profile shapes of the fairings <NUM>, <NUM>, <NUM> are different in that the side fairings <NUM>, <NUM> are more curved than other embodiments, and the top fairing <NUM> has a more straight angled upward extension to its upper terminal point <NUM> at which time it then assumes a curved, convex profile shape to its back end. Additionally, the fairings <NUM>, <NUM>, <NUM> do not terminate at the end of the trailer <NUM> in the longitudinal direction <NUM> but rather extend beyond the back end <NUM> so that they are all located rearward of the back end <NUM> in the longitudinal direction <NUM>. The fairings <NUM>, <NUM>, <NUM> may each extend up to three inches rearward of the back end <NUM> in the longitudinal direction <NUM>.

Additionally optimized savings are achieved with mudflaps <NUM> which have openings to allow air to flow through. These may be achieved with slots or holes in these mudflaps <NUM>. These openings are configured to stop or reduce energy of projectiles passing which pass through them while still allowing air to pass through. These mudflaps <NUM> are attached to move with bogie assembly mounted behind rear most tires.

The Preferred embodiment consists of a pair of front skirts <NUM>, <NUM> longer than the rear skirts <NUM>, <NUM>, from <NUM> to <NUM> (<NUM>" to <NUM>") in length front to back and a distance of the ground between (distance between ground and bottom of the skirt of <NUM> and <NUM> (<NUM>" and <NUM>") and a pair of rear skirts <NUM>, <NUM> from <NUM> to <NUM> (<NUM>" to <NUM>") in length front to back and a ground clearance of <NUM> (<NUM>") to up to <NUM> (<NUM>"). With top <NUM> and side <NUM>, <NUM> fairings with a peak thickness off the wall or top of <NUM>,<NUM> (<NUM>") to <NUM>,<NUM> (<NUM>") and a length front to back of <NUM> to <NUM>,<NUM> (<NUM>" to <NUM>") which extend less than <NUM>,<NUM> (<NUM>") off the back of the trailer. Mudflaps <NUM> of a slotted or porous design could also be included and positioned behind the tires of the bogie assembly <NUM>. This combination enables a stabilized wake structure behind the trailer <NUM> without requiring parts to move during normal operation of driving and loading trailers. In this Preferred embodiment it was found that having rear skirts <NUM>, <NUM> that do not taper in towards the center of the trailer <NUM> at all or less than <NUM>,<NUM> (<NUM>") from the side of the trailer <NUM> is optimal.

The apparatus again includes front trailer skirts <NUM>, <NUM> and trailer rear skirts <NUM>, <NUM> but in this embodiment they are connected by connecting portions <NUM>, <NUM>. The first trailer skirt <NUM> extends rearward in the longitudinal direction <NUM> to a rearward most point <NUM> that is forward of the bogie assembly <NUM> in the longitudinal direction <NUM>. The connecting portion <NUM> extends rearward from the rearward most point <NUM> and covers some but not all of the height of the bogie assembly <NUM>. The first trailer rear skirt <NUM> extends from the very back end <NUM> of the trailer forward in the longitudinal direction <NUM> to the bogie assembly <NUM> and covers a portion of the rear tires of the bogie assembly <NUM> from view relative to the side view in <FIG>. The connecting portion <NUM> extends between the first trailer rear skirt <NUM> and the first trailer skirt <NUM> and has a height that is not as tall as either of these skirts <NUM>, <NUM> in the vertical direction <NUM>. Although some of the bogie assembly <NUM> is covered not all of the bogie assembly <NUM> is covered by the skirting thus allowing it to be accessed for tire or wheel repair. The components <NUM>, <NUM> and <NUM> are all parallel to the first side surface <NUM> and form a single piece extending along the bottom of the trailer <NUM>. These parts may in fact be one piece, or can be made of multiple pieces. The connecting portion <NUM>, second trailer skirt <NUM> and the second trailer rear skirt <NUM> can be configured in manners just described with respect to their counterparts <NUM>, <NUM>, <NUM> on the opposite side of the trailer <NUM> and a repeat of this information is not necessary.

The connecting portions <NUM>, <NUM> are not as tall as the skirts <NUM>, <NUM>, <NUM>, <NUM> in the vertical direction <NUM>. The connecting portions <NUM>, <NUM> can make up a greater than <NUM> meter notch, as measured in the longitudinal direction <NUM>, that allows for access to the tires and wheels of the bogie assembly <NUM>. The connecting portions <NUM>, <NUM> should only be able to extend downward to the middle of the center of the wheels in the vertical direction <NUM> to allow for bolts to be removed. Although a good portion of the tires are shown as covered in the figures, in other embodiments the connecting potions <NUM>, <NUM> extend downward only so that the upper <NUM> inches of the tires of the bogie assembly <NUM> are covered. In accordance with certain embodiments, the connecting portions <NUM>, <NUM> are located from <NUM> inch below the trailer side surfaces <NUM>, <NUM> to <NUM> inches below the upper extent of the tires of the bogie assembly <NUM>.

<FIG> show the rear section of the trailer <NUM> with emphasis on the first and second trailer rear skirts <NUM>, <NUM>. The skirts <NUM>, <NUM> can be arranged so that the bogie assembly <NUM> is able to slide past. The skirts <NUM>, <NUM> can have a front section in the lateral direction <NUM> that can have a narrow support profile to allow access for the bogie assembly <NUM>. In this regard, they front sections of the skirts <NUM>, <NUM> may not sit more than two inches inboard of the side surfaces <NUM>, <NUM> in the lateral direction <NUM>. The skirts <NUM>, <NUM> may sit up to two inches outboard of the side surfaces <NUM>, <NUM> in the lateral direction. The brackets <NUM> may be bifurcating brackets to allow for narrow support. Bifurcating brackets are those that reduce their bending stiffness after a threshold force or displacement is reached. The front sections of the skirts <NUM>, <NUM>, and in other instances the entire skirts <NUM>, <NUM>, can be parallel with their respective side surfaces <NUM>, <NUM>. The skirts <NUM>, <NUM> can be variously positioned on the trailer such that the front section of the skirts <NUM>, <NUM> that are the first <NUM>/<NUM> length of the skirts <NUM>, <NUM> in the longitudinal direction <NUM> can be inboard of their respective side surfaces <NUM>, <NUM> by up to two inches, and so that the rearward <NUM>/<NUM> of the skirts <NUM>, <NUM> in the longitudinal direction <NUM> can be inboard up to four inches from their respective side surfaces <NUM>, <NUM>. In the <FIG> embodiments, the front <NUM>/<NUM> of the skirts <NUM>, <NUM> are located outboard of their respective side surfaces <NUM>, <NUM>, and the rearward <NUM>/<NUM> of the skirts <NUM>, <NUM> extend inboard in the lateral direction <NUM> until they terminate at their rearward ends inboard of the side surfaces <NUM>, <NUM> in the lateral direction <NUM>. The front <NUM>/<NUM> of the skirts <NUM>, <NUM> are parallel to the side surfaces <NUM>, <NUM>, and the back <NUM>/<NUM> section of the skirts <NUM>, <NUM> are angled to the side surfaces <NUM>, <NUM>. It is to be understood that other embodiments have the entire rear skirts <NUM>, <NUM> parallel to the side surfaces <NUM>, <NUM> and the back <NUM>/<NUM> of these skirts <NUM>, <NUM> are not angled inward or outward in the lateral direction <NUM>. In the preferred embodiment, the rear skirts <NUM>, <NUM> are parallel because converging back skirts <NUM>, <NUM> result in increasing the energy of air flow entering the wake behind the trailer <NUM>.

The back sections of the skirts <NUM>, <NUM> are tapered so as to reduce chances of the skirts <NUM>, <NUM> impacting the ground <NUM> caused by the departure angle. <FIG> shows the back <NUM>/<NUM> section of the skirts <NUM>, <NUM> angled upwards in the vertical direction <NUM> from the bottom edge of the forward <NUM>/<NUM> sections so that contact with the ground <NUM> is less likely.

The apparatus <NUM> may thus include the top fairing <NUM>, side fairings <NUM> and <NUM>, both of the forward trailer skirts <NUM>, <NUM>, and both of the trailer rear skirts <NUM>, <NUM>. The components of the apparatus <NUM> can be made so that they do not have any moving parts during standard, forward driving use of the trailer <NUM>. The apparatus <NUM> may lack any parts that fold or flex during standard use. The apparatus <NUM> can be constructed so that it does not interfere with opening of the door at the back end <NUM>. The apparatus <NUM> may improve fuel savings of the trailer <NUM> when used. The apparatus <NUM> can be arranged so that the tires of the bogie assembly <NUM> are not always covered and are observable due to a break in skirting in the longitudinal direction <NUM>.

Testing of the apparatus <NUM> has been conducted in which the disclosed system exhibited an improvement in aerodynamic performance from an industry leading boat tail and skirt solution. Further, testing of the apparatus <NUM> has unexpectedly discovered that the coefficient of drag decreased from <NUM> to <NUM> at <NUM>,<NUM> per hour (<NUM> miles per hour) with <NUM> degrees of yaw (<NUM>%). This is a surprising result because a full length skirt even covering the wheels resulted in a <NUM>% reduction in drag and end fairings <NUM>, <NUM>, <NUM> typically result in a <NUM>% - <NUM>% drag reduction. Thus even with the added drag of the gap present between the front skirts <NUM>, <NUM> and the trailer rear back skirts <NUM>, <NUM> the combination gains about a <NUM>% drag improvement from this combination. One would expect the present design with the gap to perform worse than the full length skirt, but it does better. Further, the increase in performance is higher than the addition of full length skirt coverage <NUM>% plus fairings <NUM>%-<NUM>% (<NUM>%-<NUM>%) thus demonstrating that the apparatus <NUM> functions as a system in that the components achieve together in synergistic combination with one another a better performance than the sum of the individual components themselves. Further greater than additive results, these results have been confirmed with computational fluid dynamics, full scale drag measurements utilizing torque measurements, and fuel economy testing utilizing fuel flow meters.

<FIG> illustrate a truck <NUM> transporting a trailer <NUM> according to an embodiment of the invention that features back of the trailer fairings <NUM>, <NUM> in accordance with another exemplary embodiment. The truck <NUM> and trailer <NUM> combination extends in a longitudinal direction <NUM> of the trailer <NUM> which is the general direction of travel as the tractor <NUM> pulls the trailer <NUM> forward. The side fairings <NUM>, <NUM> direct airflow in an optimal manner around the back of the trailer <NUM> so that drag on the trailer <NUM> during travel is optimally reduced. The geometric design of the side fairings <NUM>, <NUM> includes features that result in this optimal reduction of drag. The side fairings <NUM>, <NUM> are located proximate to the back end <NUM> of the trailer <NUM> and are attached to the trailer <NUM> and are forward of the back end <NUM> in the longitudinal direction <NUM>. In some instances the side fairings <NUM>, <NUM> extend rearward of the back end <NUM> in the longitudinal direction <NUM>. The side fairings <NUM>, <NUM> are located at the back end of the trailer <NUM> because they are designed to effect the flow of air at the back end of the trailer <NUM> and behind the trailer <NUM> during travel. The first and second trailer skirts <NUM>, <NUM> and first and second rear skirts <NUM>, <NUM> are also present on the trailer <NUM>.

As shown in <FIG>, the side fairing <NUM>, <NUM> extends in a vertical direction <NUM> of the trailer <NUM> along some, but not all, of the vertical height of the trailer <NUM>. The side fairing <NUM>, <NUM> is located closer to the top surface <NUM> of the trailer <NUM> than a bottom surface of the trailer <NUM>. The side fairing <NUM>, <NUM> may be located at the top surface <NUM>, or it may be spaced some distance from the top surface <NUM> in the vertical direction <NUM>. The side fairing <NUM>, <NUM> is mounted to the side surface <NUM> of the trailer <NUM>. In some instances, the side surface <NUM> can include grooves <NUM> that extend in the horizontal direction/longitudinal direction <NUM>. The side fairing <NUM>, <NUM> may be provided with ribs <NUM> that are disposed within these grooves <NUM> in order to allow the side fairing <NUM>, <NUM> to fit on the side surface <NUM>.

With reference to <FIG>, the top faring <NUM> is likewise located at the back end of the trailer <NUM> so that it is closer to the back end <NUM> of the trailer <NUM> than to the front terminal end of the trailer <NUM>. The top fairing <NUM> may be spaced some amount forward of the back end <NUM> in the longitudinal direction <NUM>, may terminate right at the back end <NUM>, or may extend rearward from the back end <NUM> in the longitudinal direction <NUM>. The top fairing <NUM> may extend all the way across the top surface <NUM> in the lateral direction <NUM> of the trailer <NUM> so as to be located at both the right and left side surfaces <NUM>, <NUM>. Alternatively, the top fairing <NUM> may be spaced inboard from one or both of the side surfaces <NUM>, <NUM>. The right and left side fairings <NUM>, <NUM> can be identical in configuration to one another, or may have different geographical shapes or include different members, such as mounting members.

<FIG> is a side view of the back end of the trailer <NUM> with the top fairing <NUM> positioned onto the top surface <NUM> of the trailer <NUM>. The top fairing <NUM> has a leading airflow surface <NUM> that is forward of a tailing airflow surface <NUM> in the longitudinal direction <NUM>. The top fairing <NUM> may be made of a single component or any number of components. The leading airflow surface <NUM> and the tailing airflow surface <NUM> may be just the surfaces of one or more portions of the top fairing <NUM>, or may include in addition to the surfaces some thickness or portion or the rest of the top fairing <NUM>. As such, it is to be understood that as used herein that the leading airflow surface <NUM> and the tailing airflow surface <NUM> includes the surface of some of the fairing <NUM>, concerning both the top fairing <NUM> and the side fairing <NUM>, <NUM>, and may include some thickness or other portion of the fairing <NUM> in addition to the surface. It is to be understood that as used herein, when discussing the orientation of the surfaces <NUM>, <NUM> with respect to angles, radii, locations, ranges, etc. the portion of the surfaces <NUM>, <NUM> that are being measured or discussed are the outer surfaces of the leading airflow surface <NUM> and the tailing airflow surface <NUM> and not interior portions, if any, of these surfaces <NUM>, <NUM>. The surfaces <NUM>, <NUM> can be made of plastic and may be formed through a thermal plastic forming process.

The leading airflow surface <NUM> has a leading edge <NUM> that is the forward most portion of the leading airflow surface <NUM> in the longitudinal direction <NUM>. Forward of the leading edge <NUM> is an anchoring flange <NUM>, but in other embodiments, for example as shown in the <FIG> embodiment, the leading edge <NUM> is the forward most portion of the entire top fairing <NUM>. The leading airflow surface <NUM> can be oriented within an angular range <NUM> that is from <NUM>-<NUM> degrees. The angular range <NUM> is oriented rearward in the longitudinal direction <NUM>. The angular range <NUM> includes a vertex <NUM> that is located at the leading edge <NUM>. An arm <NUM> extends from the vertex <NUM> rearward in the longitudinal direction <NUM>, and another arm <NUM> likewise extends from the vertex <NUM> rearward in the longitudinal direction <NUM> so that the arms <NUM>, <NUM> and the vertex <NUM> bound the angular range <NUM>. The angle of the angular range <NUM> is measured relative to the top surface <NUM>. In this regard, an angle of <NUM> degrees is parallel to the top surface <NUM>, and an angle of the angular range <NUM> that is <NUM> degrees is normal to the top surface <NUM>.

The leading airflow surface <NUM> is positioned so that all of it is located within the angular range <NUM>. In this regard, the angular range <NUM> is from <NUM> degrees to <NUM> degrees so that it is from <NUM> degrees to <NUM> degrees angled with respect to the top surface <NUM>. The preferred orientation of the leading airflow surface <NUM> is from <NUM> degrees to <NUM> degrees. In the embodiment shown, the leading airflow surface <NUM> is <NUM> degrees. The leading airflow surface <NUM> is a flat surface that lies in a plane <NUM>. It is therefore the case that the angular orientation of the leading airflow surface <NUM> does not change along its entire length in the longitudinal direction <NUM>, and the entire leading airflow surface <NUM> is located within the angular range <NUM>.

The leading airflow surface <NUM> ends at a meeting location <NUM> where it meets the tailing airflow surface <NUM>. The tailing airflow surface <NUM> need not be completely located within the angular range <NUM>. The tailing airflow surface <NUM> may be partially located within the angular range <NUM>. The tailing airflow surface <NUM> is a curved surface that extends from the meeting location <NUM> to a tailing airflow surface terminal end <NUM>. A flange of the top fairing <NUM> extends from the tailing airflow surface terminal end <NUM> to a terminal tailing end <NUM>. The tailing airflow surface terminal end <NUM> is at the back end <NUM> or is forward of the back end <NUM> in the longitudinal direction <NUM>. In other instances, the tailing airflow surface <NUM> extends to a terminal tailing end <NUM> of the top fairing <NUM> and a flange as previously mentioned is not present. In the embodiment shown, the tailing airflow surface <NUM> is curved at a set amount so that the entire tailing airflow surface <NUM> has but a single radius <NUM>. The radius <NUM> is in the range from <NUM> millimeters to <NUM> millimeters. In more preferred embodiments, the radius <NUM> is from <NUM> millimeters to <NUM> millimeters.

The leading airflow surface <NUM> and the tailing airflow surface <NUM> are oriented with respect to one another so that they share a common tangent line <NUM>. The common tangent line <NUM> lies in the plane <NUM> that the flat leading airflow surface <NUM> also lies. The common tangent line <NUM> is also a tangent line to the tailing airflow surface <NUM> at the meeting location <NUM>. It is therefore the case that the leading airflow surface <NUM> and the tailing airflow surface <NUM> both share a common tangent line <NUM> at the meeting location <NUM> between the leading airflow surface <NUM> and the tailing airflow surface <NUM>. The meeting location <NUM> is the point of engagement between the leading airflow surface <NUM> and the tailing airflow surface <NUM> and in so far as the common tangent line <NUM> is common to both of these surfaces <NUM>, <NUM> it is to be understood that both the leading airflow surface <NUM> and the tailing airflow surface <NUM> simultaneously exist at the meeting location <NUM>. In this regard, since both surfaces <NUM>, <NUM> exist at the meeting location <NUM>, the common tangent line <NUM> is common to both the leading airflow surface <NUM> and the tailing airflow surface <NUM> so that these two surfaces <NUM>, <NUM> share a common tangent line <NUM> at this meeting location <NUM>. This arrangement affords airflow off of the leading airflow surface <NUM> to channel against the tailing airflow surface <NUM> with no disruption. The orientation of the leading airflow surface <NUM>, and the size of the radius <NUM> and the common tangent line <NUM> results in a geometry of the top fairing <NUM> that causes air flow to travel over the top fairing <NUM> and around the rear of the trailer <NUM> to reduce dragging force while the tractor <NUM> is hauling the trailer <NUM> to improve its fuel efficiency.

The leading air flow surface <NUM> is spaced from the top surface <NUM> so that a gap <NUM> is present and the portions of the top fairing <NUM> that are below or carry the leading air flow surface <NUM> are not in engagement with the top surface <NUM>. The anchoring flange <NUM> is attached to the top surface <NUM> and may engage the top surface <NUM>. The top fairing <NUM> has a frame <NUM> engages the top surface <NUM> and can be present to help reinforce the portions of the top fairing <NUM> that include the leading airflow surface <NUM> and the tailing airflow surface <NUM>. The frame <NUM> is located below the leading air flow surface <NUM> in the vertical direction <NUM> and is not located below the tailing airflow surface <NUM>. The frame <NUM> can be a separate component from the leading air flow surface <NUM> or may be simply a lower section of the leading air flow surface <NUM> and integrally formed with the leading air flow surface <NUM>. The tailing airflow surface <NUM> is spaced from the top surface <NUM> from the meeting location <NUM> to the tailing airflow surface terminal end <NUM> at which point it may engage the top surface <NUM>. The tailing air flow surface <NUM> could cover a rain gutter of the top surface <NUM> and does not extend beyond the back end <NUM> of the trailer <NUM>.

It is to be understood that the frame <NUM> can be a component that is separate from the leading airflow surface <NUM> and the tailing airflow surface <NUM>, or may be integrally formed with these surfaces <NUM>, <NUM> and made of the same or different material than the surfaces <NUM>, <NUM>. The frame <NUM> may extend across and engage both of the surfaces <NUM>, <NUM>. If the surfaces <NUM>, <NUM> include thickness and not just the outer surfaces that are measured, the frame <NUM> may still be present and the frame <NUM> could be part of these thicknesses even if the frame <NUM> is integrally formed with the surfaces <NUM>, <NUM>.

Another embodiment of the top fairing <NUM> is shown with reference to <FIG>. The leading airflow surface <NUM> is different in that it is not a flat surface in a single plane <NUM>, but is instead a curved surface. The flat leading airflow surface <NUM> is replaced by a curved surface with a leading airflow surface radius <NUM>. The leading airflow surface radius <NUM> is larger than <NUM> millimeters. Although curved, the leading airflow surface <NUM> is completely located within the angular range <NUM>, that as previously stated is from <NUM> degrees to <NUM> degrees. The tailing airflow surface <NUM> is not a single curved surface with a single radius <NUM>, but is instead a pair of curved surfaces in which each have their own radius. The first curved surface has a radius <NUM>, and the second curved surface of the tailing airflow surface <NUM> has a different radius <NUM>. Although a pair of curved surfaces are present, all of the radii of the curved surface of the tailing airflow surface <NUM> are each in the range of <NUM> millimeters to <NUM> millimeters. If multiple additional curved surfaces are present in the tailing airflow surface <NUM>, their radii will likewise be in the range from <NUM> millimeters to <NUM> millimeters.

The meeting location <NUM> occurs between the leading airflow surface <NUM> and the curved surface of the tailing airflow surface <NUM> that has the radius <NUM>. The leading airflow surface <NUM> and the tailing airflow surface <NUM> are both curved and share a common tangent line <NUM> at the meeting location <NUM>. The vertex <NUM> is located at the terminal end that is the forward most location of the top fairing <NUM>. The leading airflow surface <NUM> engages the top surface <NUM>. The top fairing <NUM> also includes a frame <NUM> that is rearward of the meeting location <NUM> in the longitudinal direction <NUM> and is located only under the tailing airflow surface <NUM>. The frame <NUM> can be arranged as previously discussed and a repeat of this information is not necessary. The tailing airflow surface <NUM> contacts the back end <NUM> and extends beyond the back end <NUM> and is rearward of the trailer <NUM> in the longitudinal direction <NUM>. In other embodiments, the tailing airflow surface <NUM> may not engage the back end <NUM>. The various elements of the top fairing <NUM> can be modified or arranged in the manners previously discussed with reference to the top fairing <NUM> in <FIG> and a repeat of this information is not necessary. The top fairing <NUM> with the modifications noted in <FIG> allows for airflow to be directed over the trailer <NUM> to reduce drag and increase aerodynamic performance.

<FIG> is a detailed view of the front portion of the top fairing <NUM> in accordance with certain exemplary embodiments. The top fairing <NUM> has an anchoring flange <NUM> that is attached to the top surface <NUM> with double sided tape <NUM> that engages the bottom of the anchoring flange <NUM> and the top surface <NUM>. The double sided tape <NUM> extends in the longitudinal direction <NUM> an amount that is less than the length of the anchoring flange <NUM> in the longitudinal direction <NUM>. The double sided tape <NUM> can be spaced rearward from the forward most leading edge of the anchoring flange <NUM> in the longitudinal direction <NUM> so that a space is present under the anchoring flange <NUM> forward of the double sided tape <NUM> in the longitudinal direction <NUM>. The anchoring flange <NUM> has a chamfer <NUM> located at is forward most end in the longitudinal direction <NUM> that functions to reduce the profile of the anchoring flange <NUM> and direct air flow over the anchoring flange <NUM> in a more streamlined fashion. The chamfer <NUM> may be provided at an angle that is in the range from <NUM> degrees to <NUM> degrees. The chamfer <NUM> may be formed by machining the end of the anchoring flange <NUM>. The leading airflow surface <NUM> engages anchoring flange <NUM> at the leading edge <NUM>. The double sided tape <NUM> spaces the leading airflow surface <NUM> from the upper surface <NUM> so that a gap <NUM> exists between the upper surface <NUM> and the leading edge <NUM>. The gap <NUM> is a space at this location in which the leading edge <NUM> does not engage the upper surface <NUM>. The entire leading airflow surface <NUM> can likewise be spaced from and free from engagement with the upper surface <NUM> along its length, or just a portion of the leading airflow surface <NUM> can be free from engagement with the upper surface <NUM> extending rearward from the leading edge <NUM> in the longitudinal direction <NUM>. The entire anchoring flange <NUM> is free from engagement with the top surface <NUM>, but it may engage the top surface <NUM> in certain exemplary embodiments. The double sided tape <NUM> secures the anchoring flange <NUM> to the top surface <NUM> and may be between the anchoring flange <NUM> and the top surface <NUM> to prevent their engagement.

The frame <NUM> is shown attached to the top surface <NUM> with reference to <FIG>. The trailer <NUM> includes brackets <NUM> at the top of the trailer <NUM> on opposite sides in the lateral direction <NUM>. The frame <NUM> may be located under the bracket <NUM> so as to be between the bracket <NUM> and the top surface <NUM>. One or more bars <NUM> extend between and to both of the brackets <NUM> in the lateral direction <NUM>. The bars <NUM> may go through holes of the frame <NUM> to secure the frame <NUM> to the top surface <NUM>, or may be positioned on top of or otherwise engage the frame <NUM> to secure the frame <NUM> to the top surface <NUM>. The use of bars <NUM> may allow the frame <NUM>, and consequently the leading airflow surface <NUM> and the tailing airflow surface <NUM> to be attached to the trailer <NUM> without having to drill holes through the top surface <NUM> which could results in rain or contaminants entering the interior of the trailer <NUM>. In this manner, the interior of the trailer <NUM> is made more secure by the use of the brackets <NUM> and the bars <NUM> to retain the top fairing <NUM> to the trailer <NUM>. Although described as utilizing the bars <NUM> to secure the top fairing <NUM>, the bars <NUM> are not used in other embodiments. In these instances, the frame <NUM> has flanges that are positioned under the brackets <NUM> and the brackets <NUM> are tightened down onto these flanges of the frame <NUM> to secure the frame <NUM> to the top surface <NUM>. Additional securement by the double sided tape <NUM> will also aid in securing the top fairing <NUM> to the top surface <NUM>.

Another embodiment of the fairing <NUM> is illustrated in <FIG> in which the fairing is a side fairing <NUM>, <NUM>. The variously described embodiments and variations as previously discussed with respect to the top fairing <NUM> are applicable as well to the side fairing <NUM>, <NUM> and a repeat of this information is not necessary. The side fairing <NUM>, <NUM> functions to direct the flow of air around the side of the trailer <NUM> and to an area behind the trailer to result in less drag on the trailer <NUM> when the tractor <NUM> is transporting the trailer <NUM>. Although a second side fairing <NUM>, <NUM> is not shown at the opposite side of the trailer <NUM> in the lateral direction <NUM> in <FIG>, it is to be understood that such a second side fairing <NUM>, <NUM> is present in other embodiments. The side fairing <NUM>, <NUM> again has an anchoring flange <NUM> attached to the side surface <NUM>, and a leading airflow surface <NUM> that follows the anchoring flange <NUM> in the longitudinal direction <NUM>, and a tailing airflow surface <NUM> that follows the leading airflow surface <NUM> in the longitudinal direction <NUM>. The anchoring flange <NUM> may include the chamfer <NUM> in some embodiments, and it may be provided at an angle from <NUM> degrees to <NUM> degrees to enhance the aerodynamic properties of the side fairing <NUM>, <NUM>.

The leading airflow surface <NUM> is again a flat surface that lies in a plane <NUM> and is completely contained from its leading edge <NUM> to the meeting location <NUM> within the angular range <NUM>. The angular range <NUM> of the leading airflow surface <NUM> has a maximum range of degrees that are different than that as previously described with respect to the angular range <NUM> of the leading airflow surface <NUM> of the top surface <NUM>. In this regard, the angular range <NUM> of the side fairing <NUM>, <NUM> is from <NUM> degrees to <NUM> degrees. Again, the angular range <NUM> is measured with respect to the side surface <NUM> such that <NUM> degrees is parallel to the side surface <NUM>, <NUM> degrees is at a <NUM> degree angle to the side surface <NUM>, <NUM> degrees is at a <NUM> degree angle to the side surface <NUM>, and so on. The orientation of the angular range <NUM> is rearward in the longitudinal direction <NUM> in that the arms <NUM>, <NUM> of the angular range <NUM> extend rearward in the longitudinal direction <NUM> from the vertex <NUM>. In more Preferred embodiments, the angular range <NUM> is from <NUM> degrees to <NUM> degrees. In a preferred embodiment, the angular range <NUM> is <NUM> degrees.

The entire leading airflow surface <NUM> is located within the angular range <NUM>, and the leading airflow surface <NUM> has a common tangent line <NUM> with the tailing airflow surface <NUM> at the meeting location <NUM>. The tailing airflow surface <NUM> is a single curved surface with a single radius <NUM>. The tailing airflow surface terminal end <NUM> is located at the terminal tailing end <NUM> of the fairing <NUM> and is forward of the back end <NUM> in the longitudinal direction <NUM>. The side surface <NUM> may translate to the back end <NUM> by way of a radius or curved corner, and the tailing airflow surface terminal end <NUM> and the terminal tailing end <NUM> may both be forward of this radius or curved corner in the longitudinal direction <NUM>. The tailing airflow surface <NUM> has a radius <NUM> that is from <NUM> millimeters to <NUM> millimeters. In more preferred embodiments, the radius <NUM> is from <NUM> millimeters to <NUM> millimeters. In a preferred embodiment, the radius <NUM> is <NUM> millimeters. Selection of a radius <NUM> within the listed ranges/distance provides airflow around the side fairing <NUM>, <NUM> to reduce drag, and this selection coupled with the tangency at the meeting location <NUM> along with the angle of the leading airflow surface <NUM> provides beneficial aerodynamic properties to the side fairing <NUM>, <NUM>.

The frame <NUM> engages the side surface <NUM> and is located below the tailing airflow surface <NUM> and is not below the leading airflow surface <NUM>. The frame <NUM> is spaced along the underside of the tailing airflow surface <NUM> so as to be spaced from both the meeting location <NUM> and the terminal tailing end <NUM> in the longitudinal direction <NUM>. A gap <NUM> can be present to space the leading airflow surface <NUM> from the side surface <NUM> so that these surfaces <NUM>, <NUM> do not engage one another.

The side fairing <NUM>, <NUM> is shown in another embodiment with reference to <FIG>. Again, the side fairing <NUM>, <NUM> may be configured the same as in other exemplary embodiments and a repeat of this information is not necessary. The side fairing <NUM>, <NUM> lacks an anchoring flange <NUM> and the leading edge <NUM> forms the terminal forward end of the side fairing <NUM>, <NUM> in the longitudinal direction <NUM>. The vertex <NUM> is located at the leading edge <NUM>, and the angular range <NUM> is again from <NUM> degrees to <NUM> degrees for the side fairing <NUM>, <NUM> with a preferred range of <NUM> degrees to <NUM> degrees. The entire leading airflow surface <NUM> is within the angular range <NUM>, and the leading airflow surface <NUM> is not flat but is instead curved with a leading airflow surface radius <NUM> that is larger than <NUM> millimeters. The tailing airflow surface <NUM> is made up of multiple curved surfaces with their own radius. However, all of the radii of the curved surfaces making up the tailing airflow surface are from <NUM> millimeters to <NUM> millimeters. This range is for individual radii and not for the addition of all of the radii such that each one of the radii <NUM>, <NUM> are by itself within this range. The tailing airflow surface <NUM> terminates at the side surface <NUM> and the terminal tailing end <NUM> and the tailing airflow surface terminal end <NUM> are coincident. These ends <NUM>, <NUM> are forward of the back end <NUM> in the longitudinal direction <NUM> and are forward of rounded corners that transition the trailer <NUM> from the side surface <NUM> to the back end <NUM> in the longitudinal direction <NUM>.

The curved leading airflow surface <NUM> and the portion of the tailing airflow surface <NUM> at the meeting location <NUM> both have a common tangent line <NUM>. Again, both surfaces <NUM> and <NUM> are considered to exist at the meeting location <NUM> and they are tangent to one another at this point. This tangency helps to direct the flow of air across the side fairing <NUM>, <NUM> at this location. The side fairing <NUM>, <NUM> also has a frame <NUM> that engages the side surface <NUM> and is inboard of most of the leading airflow surface <NUM> in the lateral direction <NUM> and is between and spaced from both the meeting location <NUM> and the leading edge <NUM> in the longitudinal direction <NUM>. Although not shown on the left side of the trailer <NUM>, an additional side fairing <NUM>, <NUM> could be included and arranged in a similar manner as the one illustrated in <FIG>.

<FIG> is a perspective view of the side fairing <NUM>, <NUM> in which an anchoring flange <NUM> is present and the leading airflow surface <NUM> is flat and lays in a plane <NUM>. The tailing airflow surface <NUM> is curved and a flange is located at the end of the side fairing <NUM>, <NUM> with the terminal tailing end <NUM> at the flange. The side fairing <NUM>, <NUM> can be attached to the side surface <NUM> through the use of bolts that extend through the leading airflow surface <NUM> or the tailing airflow surface <NUM> and into the side surface <NUM>. The bolts may likewise extend through a frame <NUM> of the side fairing <NUM>, <NUM> in some arrangements. The top and/or bottom of the side fairing <NUM>, <NUM> in the vertical direction <NUM> can be provided with a sidewall <NUM> that functions to close the interior of the side fairing <NUM>, <NUM> and that may act to direct airflow around the side fairing <NUM>, <NUM> or prevent disruption of airflow at the side fairing <NUM>, <NUM> to prevent drag. Although shown with the sidewall <NUM>, it is to be understood that the sidewall <NUM> need not be present in other exemplary embodiments of the side fairing <NUM>, <NUM>. Further, the sidewall <NUM> may likewise be present in embodiments of the top fairing <NUM>. The sidewalls <NUM> may also function to prevent deformation of the fairing <NUM>.

<FIG> shows the side fairing <NUM>, <NUM> attached to the side surface <NUM> via bolts into the side surface <NUM>. The side fairing <NUM>, <NUM> is configured relative to the back door of the trailer <NUM> so that the back door may be opened and closed without interference with the side fairing <NUM>, <NUM>. The tailing airflow surface <NUM> blends into the side surface <NUM> so there is a smooth transition of air flow between these members.

<FIG> shows the side fairing <NUM>, <NUM> in which the frame <NUM> is provided with a series of ribs <NUM> that are provided in order to be located within complimentary grooves <NUM> of the trailer <NUM>. The ribs <NUM><NUM> may be of any size or shape and are located at different spots on the frame <NUM> to allow the side fairing <NUM>, <NUM> to be compatible with different trailers <NUM>. The ribs <NUM> may still be present even when the side fairing <NUM>, <NUM> is used with trailers <NUM> that do not have grooves <NUM>. In this regard, the side fairing <NUM>, <NUM> can be produced with ribs <NUM> and is compatible with trailers <NUM> with and without grooves <NUM> so that manufacturing benefits can be realized. The ribs <NUM> allow the side fairing <NUM>, <NUM> to be common with both flat side surfaces <NUM>, <NUM> and those that have grooves <NUM>.

<FIG> is a top view of a back portion of the trailer <NUM> in which the side fairing <NUM>, <NUM> is attached to the side surface <NUM>. The frame <NUM> includes a series of ribs <NUM> and the frame <NUM> may be attached to the side surface <NUM> via bolts or adhesive. The frame <NUM> can be made of steel in some arrangements, or may be made of lighter weight materials as desired. The frame <NUM> is attached to the tailing airflow surface <NUM> by double sided tape <NUM> that engages both the tailing airflow surface <NUM> and the frame <NUM>. Multiple strips of the double sided tape <NUM> can be present. The double sided tape <NUM> may not engage the ribs <NUM>. The terminal tailing end <NUM> engages the side surface <NUM> but does not extend all the way to the back end <NUM> in the longitudinal direction <NUM> so that the terminal tailing end <NUM> is forward from the back end <NUM> in the longitudinal direction <NUM>. The terminal tailing end <NUM> may engage the side surface <NUM> before the disclosed bend in the side surface <NUM> that transitions to the back surface which is the back end <NUM>. The terminal tailing end <NUM> is thus forward in the longitudinal direction <NUM> from this bend.

The frame <NUM> can be made of multiple sections that are contiguous with one another or that are spaced from one another and not in contact with one another. <FIG> shows a portion of the frame <NUM> that is wedge shaped and is located proximate to the terminal tailing end <NUM> of the side fairing <NUM>, <NUM>. Additional sections of the frame <NUM> could be present at other portions of the side fairing <NUM>, <NUM> free from engagement with the wedge section, or the wedge section illustrated may be the only portion of the frame <NUM> in the side fairing <NUM>, <NUM>. The wedge section of the frame <NUM> is attached to the side surface <NUM> and the tailing airflow surface <NUM> by double sided tape, or through a different attachment mechanism in other exemplary embodiments. The wedge section of the frame <NUM> functions to support the tailing airflow surface <NUM> and to hold this portion of the side fairing <NUM>, <NUM> to the side surface <NUM> at this location. The terminal tailing end <NUM> of the side fairing <NUM>, <NUM> terminates forward of the back end <NUM> in the longitudinal direction <NUM>. The terminal tailing end <NUM> and the coincident tailing airflow surface terminal end <NUM> are shown as engaging the trailer <NUM> forward of a bend in the trailer at the end of the side surface <NUM> and forward of the back end <NUM> in the longitudinal direction <NUM>. In other versions, the ends <NUM>, <NUM> may engage this bend, or may be free from engagement with this bend, or be rearward of the back end <NUM> in the longitudinal direction <NUM>.

The design of the top fairing <NUM> and the side faring <NUM>, <NUM> differ in that their angular ranges and their radii are different in magnitude from one another. As such, the fairing <NUM> disclosed may a leading airflow surface <NUM> with an angular range that is from <NUM> degrees to <NUM> degrees. The fairing <NUM> may have a curved tailing airflow surface <NUM> with a radius <NUM> that is in the range from <NUM> millimeters to <NUM> millimeters. In this regard, should the tailing airflow surface <NUM> be constructed of multiple curved surfaces with each having its own radius, each of the radii would be in that disclosed range from <NUM> millimeters to <NUM> millimeters.

Embodiments of the fairings exist in which the fairing, regardless of whether the fairing is the top fairing <NUM> or the side fairing <NUM>, <NUM>, is located at or forward from the back end <NUM> in the longitudinal direction <NUM> when the fairing is attached to the trailer <NUM>. In this regard, although the fairing may be right at the back end <NUM> in the longitudinal direction <NUM>, no portion of the fairing is located rearward of the back end <NUM> in the longitudinal direction <NUM>. Still further, embodiments exist in which the fairing is spaced some distance from the back end <NUM> forward in the longitudinal direction <NUM>, and no portion of the fairing is rearward to the back end <NUM> in the longitudinal direction <NUM>.

The fairings, such as the top fairing <NUM> and side fairings <NUM>, <NUM>, and other portions of the apparatus <NUM> or trailer <NUM> can be provided as those set forth in international application number <CIT>.

Another exemplary embodiment of the apparatus <NUM> on the trailer <NUM> is shown in <FIG> and includes first and second trailer skirts <NUM>, <NUM> and first and second trailer rear skirts <NUM>, <NUM>. Also included are first and second side fairings <NUM>, <NUM> and a top fairing <NUM>. The side fairings <NUM> and <NUM> do not extend the entire vertical heights of the first and second side surfaces <NUM>, <NUM> but instead only extend partially along these heights. The side fairings <NUM>, <NUM> are located closer to the upper surface <NUM> in the vertical direction <NUM> than they are to the first and second trailer rear skirts <NUM>, <NUM>. A larger gap may thus be present between the trailer rear skirts <NUM>, <NUM> to the side fairings <NUM>, <NUM> than the gap from the side fairings <NUM>, <NUM> to the upper surface <NUM> in the vertical direction <NUM>. The side fairings <NUM>, <NUM> do not engage the top fairing <NUM> and stop short of the upper surface <NUM>. The elements <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and <NUM> can be provided as discussed herein and repeating this information is not necessary. Also, the apparatus <NUM> includes mudflaps <NUM> located just rearward of the rearward tire of the bogie assembly <NUM> in the longitudinal direction <NUM>. The mudflaps <NUM> could be behind all of the rearward tires and may be provided in any number. The mudflaps <NUM> can be provided as disclosed in patent application number <CIT> entitled "Aerodynamic Mudflap".

The mudflap <NUM> that is included in the apparatus <NUM> is an aerodynamic mudflap in that it includes voids through which air may flow during driving so that less wind resistance is realized via the presence of the mudflap <NUM>. <FIG> is a front view of one possible arrangement of the mudflap <NUM>, and features a plurality of horizontally arranged horizontal louvers <NUM> in a barrier section <NUM> of the mudflap. The horizontal louvers <NUM> extend across almost the entire width of the mudflap <NUM> in the lateral direction <NUM>. The horizontal louvers <NUM> are spaced from one another in the vertical direction <NUM>. The spacing of successive horizontal louvers <NUM> in the vertical direction <NUM> increases from the bottom of the mudflap <NUM> towards the top of the mudflap <NUM> in the vertical direction <NUM>. In some instances, the spacing always increases between successive horizontal louvers <NUM>, In other instances, some of the successive horizontal louvers <NUM> have equal spacing from one another in the vertical direction <NUM>. The spacing between horizontal louvers <NUM> allows some air to flow therethrough so that some air resistance savings are realized. The aerodynamic section <NUM> is designed to maximize airflow through the mudflap <NUM> and is located above the barrier section <NUM> in the vertical direction <NUM>. The barrier section <NUM> may not include any of the horizontal louvers <NUM> in certain embodiments. It may be provided with vertical members and other honeycomb shaped structures to provide structural rigidity to the mudflap <NUM> yet allow air to pass.

<FIG> shows the back end of the trailer <NUM> with the mudflap <NUM> incorporated into the apparatus <NUM>, but other elements of the apparatus <NUM> are not illustrated for purposes of clarity. The rear tire of the bogie assembly <NUM> is immediately forward of the mudflap <NUM> in the longitudinal direction <NUM>, and the barrier and aerodynamic sections <NUM>, <NUM> are noted. Rotation of the tire in the direction R will direct water and materials off of the tire along lines indicated for example by lines TM in <FIG>. The horizontal louvers <NUM> are angled such that the voids going between the horizontal louvers <NUM> travel through in an orientation having components that extend in both the longitudinal direction <NUM> and the vertical direction <NUM>. The angled horizontal louvers <NUM> are oriented to stop the water and materials from lines such as lines TM from going through the mudflap <NUM>. The aerodynamic section <NUM> need not have horizontal louvers <NUM>, or may have them in some embodiments. It is anticipated that the higher positioning of the aerodynamic section <NUM> may minimize or prevent the need to block water and materials because they will not be directed that high up do to its positioning relative to the tire of the bogie assembly <NUM>.

The top fairing <NUM> may be constructed so that it functions as half of an airfoil in that airflow can go over the top of the top fairing <NUM> but cannot go under the top fairing <NUM>. With reference to <FIG>, the leading edge <NUM> contacts or is otherwise adjacent the upper surface <NUM> at the anchoring flange <NUM> so that this area of the top fairing <NUM> is sealed to prevent all, or any noticeable/significant, air from flowing underneath the top fairing <NUM> to be between the top fairing <NUM> and the upper surface <NUM>. Instead, air flows across the leading airflow surface <NUM> on the upper side of the top fairing <NUM> and is directed upwards in the vertical direction <NUM> and then upon further travel across the tailing airflow surface <NUM> on the upper side is directed downwards in the vertical direction <NUM>. As such, the upper surface of the top fairing <NUM> is arranged so that forward travel of the trailer <NUM> results in airflow, moving rearward in the longitudinal direction <NUM>, to be first directed upwards in the vertical direction <NUM> and then downwards in the vertical direction <NUM> off of the top fairing <NUM>. When this occurs, there is no or negligible airflow under the top fairing <NUM> such that there is no airflow between the upper surface <NUM> and the top fairing <NUM>. The tenn "negligible airflow" can be defined as meaning that the volume of airflow moving between the top fairing <NUM> and the upper surface <NUM> is less than <NUM>% of the volume of airflow moving over the upper surface of the top fairing <NUM> when one measures the volume of the airflow from the top fairing <NUM> to a distance <NUM>,<NUM> (one inch) above the top fairing <NUM>.

The side fairings <NUM>, <NUM> may be constructed in a similar manner as immediately discussed with respect to the top fairing <NUM>. <FIG> shows the side fairing <NUM> (the side fairing <NUM> could be made the same way) with the leading edge <NUM> against the side surface <NUM>. No, or negligible, air flows under the leading edge <NUM> such that no or negligible air will flow between the side surface <NUM> and the side fairing <NUM> in the longitudinal direction <NUM>. The top of the side fairing <NUM> is shaped so that air will flow first outboard in the lateral direction <NUM> and then will flow inboard in the lateral direction <NUM> upon flowing forward to rearward in the longitudinal direction <NUM>. In this regard, airflow can be directed outward in the lateral direction <NUM> across the leading airflow surface <NUM>, and then subsequently inboard in the lateral direction <NUM> across the tailing airflow surface <NUM>.

Regarding the back end <NUM> of the trailer <NUM>, the top fairing <NUM> may extend past the back end <NUM> so as to be located rearward of the back end <NUM> in the longitudinal direction <NUM> as shown for example in <FIG>. Alternatively, the top fairing <NUM> may extend in the longitudinal direction <NUM> short of the back end <NUM> so that some portion of the upper surface <NUM> is visible and uncovered between the top fairing <NUM> and the back end <NUM>, or the top fairing <NUM> could terminate in the longitudinal direction <NUM> right at the end of the upper surface <NUM> but not past the back end <NUM> as shown for example in <FIG>. The side fairings <NUM>, <NUM> may extend in the longitudinal direction <NUM> just short of the back end <NUM> so that some portion of the side surfaces <NUM>, <NUM> are uncovered between the side fairings <NUM>, <NUM> and the back end <NUM> as shown for example in <FIG>. Alternatively, in other embodiments the side fairings <NUM>, <NUM> extend past the back end <NUM> in the longitudinal direction <NUM> and are thus behind the back end <NUM>. The side fairings <NUM>, <NUM> may be configured in the same manner as the top fairing <NUM> and these components can all be variously designed as discussed herein.

The apparatus <NUM> may be arranged so that the skirts <NUM>, <NUM> and rear skirts <NUM>, <NUM> are present, and the fairings <NUM>, <NUM>, <NUM> are likewise on the trailer <NUM> such that none of these elements extend past the back end <NUM> in the longitudinal direction <NUM>. In these arrangements, the top fairing <NUM>, the side fairing <NUM>, and the side fairing <NUM> all stop short of the back end <NUM> so that none of them extend rearward of the back end <NUM> in the longitudinal direction <NUM>. The apparatus <NUM> is arranged so that the top fairing <NUM> and side fairings <NUM>, <NUM> do not form a boat tail. The fairings <NUM>, <NUM>, <NUM> are all set up so that greater than ½ of their aerodynamic functionality is located on the trailer <NUM> and less than ½ of their functionality is off of and behind the back end <NUM> of the trailer <NUM> in the longitudinal direction <NUM>. A boat tail will have at least ½ of its aerodynamic function located rearward of the back end <NUM> in the longitudinal direction <NUM>, and in many instances will have all of its aerodynamic functionality rearward of the back end <NUM> in the longitudinal direction <NUM>. In so far as the fairings <NUM>, <NUM>, <NUM> are incorporated into the trailer <NUM> with the skirts <NUM>, <NUM>, <NUM>, <NUM> this package will be placed onto a trailer <NUM> that lacks a boat tail, which could be a separate element from the apparatus <NUM> elements. A back end <NUM> that does not have a boat tail is shown, for example, in <FIG>.

Another feature of the apparatus <NUM> involves provision of first and second trailer rear skirts <NUM> and <NUM> that are put onto the trailer <NUM> and allow for movement of the bogie assembly <NUM> in the longitudinal direction <NUM>. <FIG> shows a side view of the trailer <NUM> with the bogie assembly <NUM> visible and between the first trailer skirt <NUM> and the first trailer rear skirt <NUM> in the longitudinal direction <NUM>. <FIG> is a top partial cross-sectional view showing portions of the trailer <NUM> and apparatus <NUM> of <FIG> in which the perimeter of the trailer <NUM> is illustrated in dashed lines. The first and second trailer rear skirts <NUM>, <NUM> are in cross-section and are positioned at the perimeter of the trailer <NUM> and are mounted thereto via brackets <NUM>. The bogie assembly <NUM> is not in cross-section in the figure and is positioned completely forward of the rear skirts <NUM>, <NUM> in the longitudinal direction <NUM>. Trailers <NUM> include bogie assemblies <NUM> that are movable in the longitudinal direction <NUM> relative to the container section and other sections of the trailer <NUM>. This movement is for adjusting for differently weighted or distributed contents of the trailer <NUM>, or for trailer transport or loading/unloaded of the contents. The bogie assembly <NUM> is uncovered by all of the skirts <NUM>, <NUM>, <NUM> and <NUM> in the illustrated position and is visible.

<FIG> are views similar to those previously described with mention to <FIG> but with the bogie assembly <NUM> moved rearward in the longitudinal direction <NUM> and covered by the trailer rear skirts <NUM>, <NUM>. The trailer rear skirts <NUM>, <NUM> may cover the entire longitudinal length of the bogie assembly <NUM> as illustrated. In this regard, the leading forward edge of the bogie assembly <NUM> is at or rearward of the leading forward edge of the trailer rear skirts <NUM>, <NUM> in the longitudinal direction <NUM>. The tailing backward edge of the bogie assembly <NUM> is at or forward of the tailing backward edge of the trailer rear skirts <NUM>, <NUM> in the longitudinal direction <NUM>. The trailer rear skirts <NUM>, <NUM> are arranged on the trailer <NUM> so that they do not interfere with the longitudinal sliding of the bogie assembly <NUM>. The trailer rear skirts <NUM>, <NUM> may both be located outboard of the bogie assembly <NUM> in the lateral direction <NUM>. The panel of the trailer rear skirt <NUM> could be completely outboard of the bogie assembly <NUM> in the lateral direction <NUM>, and the panel of the trailer rear skirt <NUM> may be completely outboard of the bogie assembly <NUM> in the lateral direction <NUM>. The brackets <NUM> retaining the panels of the trailer rear skirts <NUM>, <NUM> can be located above the tires of the bogie assembly <NUM> in the vertical direction <NUM> to afford clearance to all the trailer rear skirts <NUM>, <NUM> to be mounted yet allow the bogie assembly <NUM> to move relative thereto. The trailer rear skirts <NUM>, <NUM> could be at or located inboard from the side surfaces <NUM>, <NUM> in the lateral direction <NUM>. Although shown as being completely rearward of the trailer rear skirts <NUM>, <NUM>, the bogie assembly <NUM> could also be positioned so that part of it is covered by the trailer rear skirts <NUM>, <NUM> and other parts are not covered by the trailer rear skirts <NUM>, <NUM> in the longitudinal direction <NUM> in various exemplary embodiments. The bogie assembly <NUM> may thus be arranged to be movable in the longitudinal direction <NUM> relative to the trailer rear skirts <NUM>, <NUM> so that at least the tailing end of the bogie assembly <NUM> can be moved rearward of the leading end of the trailer rear skirts <NUM>, <NUM> in the longitudinal direction <NUM>. In the embodiment disclosed in <FIG>, the entire bogie assembly <NUM> is movable completely forward of the trailer rear skirts <NUM>, <NUM> and completely rearward of the leading forward end of the trailer rear skirts <NUM>, <NUM> in the longitudinal direction <NUM>.

Claim 1:
A trailer (<NUM>) with a bogie assembly (<NUM>), said trailer (<NUM>) comprising:
a top fairing (<NUM>) configured for being mounted to a top surface (<NUM>) of the trailer (<NUM>), wherein the trailer (<NUM>) has a longitudinal direction (<NUM>), a lateral direction (<NUM>), and a vertical direction (<NUM>), wherein the top fairing (<NUM>) is configured to be located closer to the back of the trailer (<NUM>) than to the front of the trailer (<NUM>) in the longitudinal direction (<NUM>), wherein airflow across the top fairing (<NUM>) in the longitudinal direction (<NUM>) is over an upper surface of the top fairing (<NUM>) and there is no or negligible airflow in the longitudinal direction (<NUM>) between the top fairing (<NUM>) and the top surface (<NUM>) of the trailer (<NUM>), wherein the airflow across the upper surface of the top fairing (<NUM>) in the longitudinal direction (<NUM>) moves upward in the vertical direction (<NUM>) and then subsequently downward in the vertical direction (<NUM>),
a first trailer skirt (<NUM>) configured to be carried by the trailer (<NUM>);
a second trailer skirt (<NUM>) configured to be carried by the trailer (<NUM>);
a first trailer rear skirt (<NUM>) configured to be located rearward of the first trailer skirt (<NUM>) in the longitudinal direction (<NUM>), wherein the first trailer rear skirt (<NUM>) and the first trailer skirt (<NUM>) are configured to be located closer to a first side surface (<NUM>) of the trailer (<NUM>) than to a second side surface (<NUM>) of the trailer (<NUM>) in the lateral direction (<NUM>); and
a second trailer rear skirt (<NUM>) configured to be located rearward of the second trailer skirt (<NUM>) in the longitudinal direction (<NUM>), wherein the second trailer rear skirt (<NUM>) and the second trailer skirt (<NUM>) are configured to be located closer to a second side surface (<NUM>) of the trailer (<NUM>) than to a first side surface (<NUM>) of the trailer (<NUM>) in the lateral direction (<NUM>),
characterized in that the bogie assembly (<NUM>) of the trailer (<NUM>) is movable in the longitudinal direction (<NUM>) relative to the first (<NUM>) and second (<NUM>) trailer rear skirts, wherein the bogie assembly (<NUM>) is moveable such that at least a portion of the bogie assembly (<NUM>) is positioned rearward of leading forward ends of the first (<NUM>) and second (<NUM>) trailer skirts in the longitudinal direction (<NUM>).