Patent Publication Number: US-2023159115-A1

Title: Retractable under chassis fairing

Description:
FIELD OF THE DISCLOSURE 
     The disclosure relates generally to under chassis fairings. In particular aspects, the disclosure relates to vehicles and retractable under chassis fairings. 
     BACKGROUND 
     Aerodynamic drag of a vehicle affects fuel economy. Accordingly, improving aerodynamic design results in better fuel efficiency, especially for vehicles (e.g., heavy truck vehicles) that travel long distances at high speeds. 
     One source of aerodynamic drag is the ground clearance of the vehicle. Vehicles require ground clearance to navigate road obstacles and prevent damage to an underside of the vehicle. However, increasing ground clearance increases aerodynamic drag, and therefore reducing ground clearance reduces aerodynamic drag. 
     SUMMARY 
     According to an aspect of the disclosure, an under chassis fairing includes a fairing body and at least one coupling. The fairing body includes a floor, a front wall, a left sidewall, and a right sidewall. The front wall extends from a front edge of the fairing body to the floor toward a back edge of the fairing body and is angled relative to the floor. The at least one coupling is configured to hang the fairing body from a chassis of a vehicle such that an upper edge of the left sidewall and the right sidewall is positioned at the same height as or higher than a lower side edge of the outer surface of a vehicle body of the vehicle . The at least one coupling is configured to allow movement of the fairing body from a lowered position vertically toward the chassis upon contact with a road obstacle. 
     In certain embodiments, the left sidewall and the right sidewall are planar and extend from the front wall to a back edge of the floor. 
     In certain embodiments, each of the left sidewall and the right sidewall comprises a laterally extended portion. 
     In certain embodiments, the fairing body defines a gap between a left rearward edge of the left sidewall and a right rearward edge of the right sidewall. 
     In certain embodiments, the fairing body includes a metal material. 
     In certain embodiments, the at least one coupling includes a front coupling configured to hang from a front axle of the chassis of the vehicle. 
     In certain embodiments, the at least one coupling includes a back coupling configured to hang from a rear axle of the chassis of the vehicle. 
     In certain embodiments, the at least one coupling includes at least one of a strap, a telescopic strut, a hook, or a bracket. 
     In certain embodiments, the at least one coupling includes a metal bracket. 
     In certain embodiments, the under chassis fairing further includes at least one guide configured to allow vertical movement and restrict lateral movement of the under chassis fairing relative to the chassis. 
     In certain embodiments, the at least one guide includes at least one vertical slot configured to receive at least a portion of an axle of the chassis therein. 
     In certain embodiments, the at least one coupling comprises the at least one guide. 
     In certain embodiments, the at least one guide includes a front guide configured to engage at least a portion of a front axle and a back guide configured to engage at least a portion of a rear axle. 
     According to another aspect of the disclosure, a vehicle includes a vehicle body, a chassis, and an under chassis fairing. The vehicle body has an outer surface. The chassis includes a front axle and a rear axle. The under chassis fairing hangs from the chassis. The under chassis fairing includes a fairing body and at least one coupling. The fairing body includes a floor, a front wall, a left sidewall, and a right sidewall. The front wall extends from a front edge of the fairing body to the floor toward a back edge of the fairing body and is angled relative to the floor. The at least one coupling is configured to hang the fairing body from a chassis of a vehicle such that an upper edge of the left sidewall and the right sidewall is positioned at the same height as or higher than a lower side edge of the outer surface of a vehicle body of the vehicle. The at least one coupling is configured to allow movement of the fairing body from a lowered position vertically toward the chassis upon contact with a road obstacle. 
     In certain embodiments, the under chassis fairing includes a front coupling configured to hang from the front axle of the chassis of the vehicle. 
     In certain embodiments, the under chassis fairing further includes a front guide configured to allow vertical movement and restrict lateral movement of the under chassis fairing relative to the chassis. 
     In certain embodiments, the front axle includes at least one nub inserted into at least a portion of the front guide to restrict lateral movement of the under chassis fairing relative to the chassis. 
     In certain embodiments, the under chassis fairing includes a back coupling configured to hang from the rear axle of the chassis of the vehicle. 
     In certain embodiments, the under chassis fairing further includes a back guide configured to allow vertical movement and restrict lateral movement of the under chassis fairing relative to the chassis. 
     In certain embodiments, the rear axle includes at least one nub inserted into at least a portion of the back guide to restrict lateral movement of the under chassis fairing relative to the chassis. 
     Additional features and advantages will be set forth in the detailed description which follows, and in part will be readily apparent from that description to those skilled in the art or recognized by practicing the embodiments as described herein, including the detailed description which follows, the claims, as well as the appended drawings. 
     It is to be understood that both the foregoing general description and the following detailed description are merely exemplary, and are intended to provide an overview or framework for understanding the nature and character of the claims. The accompanying drawings are included to provide a further understanding, and are incorporated in and constitute a part of this specification. The drawings illustrate one or more embodiment(s), and together with the description serve to explain principles and operation of the various embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawing figures incorporated in and forming a part of this specification illustrate several aspects of the disclosure, and together with the description serve to explain the principles of the disclosure. 
         FIG.  1 A  is a side view of a vehicle including a retractable under chassis fairing. 
         FIG.  1 B  is a top view of the vehicle and under chassis fairing of  FIG.  1 A . 
         FIG.  1 C  is a perspective view of an under chassis fairing with planar sidewalls mounted to axles of the vehicle of  FIGS.  1 A- 1 C . 
         FIG.  2 A  is a top view of the vehicle and an under chassis fairing with non-planar sidewalls mounted to axles of the vehicle of  FIGS.  1 A- 1 C . 
         FIG.  2 B  is a perspective view of the under chassis fairing of  FIG.  2 A . 
         FIG.  3 A  is a perspective view of the under chassis fairing of  FIGS.  2 A- 2 B  mounted to a chassis by mechanical joints. 
         FIG.  3 B  is a perspective view of the mechanical joint of  FIG.  3 A . 
         FIG.  4 A  is a side view of the under chassis fairing of  FIGS.  1 A- 1 C  in an extended position as the under chassis fairing approaches a road obstacle. 
         FIG.  4 B  is a side view of the under chassis fairing of  FIG.  4 A  with a front of the under chassis fairing in a retracted position and a rear of the under chassis fairing in the extended position as the under chassis fairing travels over the road obstacle. 
         FIG.  4 C  is a side view of the under chassis fairing of  FIG.  4 A  with the front of the under chassis fairing in the retracted position and the rear of the under chassis fairing in the retracted position as the under chassis fairing travels over the road obstacle. 
         FIG.  4 D  is a side view of the under chassis fairing of  FIG.  4 A  with the front of the under chassis fairing in the extended position and the rear of the under chassis fairing in the retracted position as the under chassis fairing travels over the road obstacle. 
     
    
    
     DETAILED DESCRIPTION 
     The embodiments set forth below represent the necessary information to enable those skilled in the art to practice the embodiments and illustrate the best mode of practicing the embodiments. Upon reading the following description in light of the accompanying drawing figures, those skilled in the art will understand the concepts of the disclosure and will recognize applications of these concepts not particularly addressed herein. It should be understood that these concepts and applications fall within the scope of the disclosure and the accompanying claims. 
     It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of the present disclosure. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. 
     It will be understood that when an element is referred to as being “connected” or “coupled” to another element, it can be directly connected or coupled to the other element or intervening elements may be present. In contrast, when an element is referred to as being “directly connected” or “directly coupled” to another element, there are no intervening elements present. 
     Relative terms such as “below” or “above” or “upper” or “lower” or “horizontal” or “vertical” may be used herein to describe a relationship of one element, layer, or region to another element, layer, or region as illustrated in the Figures. It will be understood that these terms and those discussed above are intended to encompass different orientations of the device in addition to the orientation depicted in the Figures. 
     The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises,” “comprising,” “includes,” and/or “including” when used herein specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. 
     Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms used herein should be interpreted as having a meaning that is consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. 
       FIGS.  1 A- 1 C  are views of a vehicle  100  including a retractable under chassis fairing  102 . The vehicle  100  further includes a vehicle body  104  (may also be referred to as a cab body) and a chassis  106  (may also be referred to as a vehicle frame) including a front axle  108  and two rear axles  110 . Although the vehicle  100  shown is a truck, it is noted that the retractable under chassis fairing  102  may be used on other types of vehicles. Further, it is noted that the under chassis fairing  102  may also be positioned underneath a trailer or any other part of the vehicle. 
     The vehicle body  104  has an outer surface  112  including a lower front edge  114  and a lower side edge  116 . Ground clearance GC is measured from the ground to the lower front edge  114  and/or the lower side edge  116 . The vehicle body  104  includes a chassis fairing  118  partially defining the outer surface  112  and the lower side edge  116 . The vehicle body  104  further includes a full side fairing  120  partially defining the outer surface  112  and the lower side edge  116 . As shown, the under chassis fairing  102  extends downwardly past the lower front edge  114  and the lower side edge  116 . 
     In certain embodiments, the under chassis fairing  102  (may also be referred to as a tub, an aerodynamic tub, etc.) includes a fairing body  122  and at least one coupling including a front coupling  124  and a back coupling  126  attaching the fairing body  122  to the vehicle body  104 . As described in more detail below, the front and back couplings  124 ,  126  are configured to hold the body in an extended lower position and allow upward vertical movement of the body when encountering an obstacle. The fairing body  122  includes a floor  128 , a front wall  130 , a left sidewall  132 A, and a right sidewall  132 B. In certain embodiments, the fairing body  122  includes a metal material and/or any other rigid material that independently retains size and shape. 
     The floor  128  is substantially horizontal when installed on a vehicle, that is, the floor is substantially parallel to the chassis  106 . The front wall  130  includes a planar portion  134  and an angled portion  136  may also be referred to as a ramp) positioned beneath the planar portion  134 . The planar portion  134  is substantially perpendicular to the floor  128 . In certain embodiments, the front wall  130  only includes an angled portion  136  (without a planar portion  134 ). The angled portion  136  extends between a front edge  137  of the fairing body  122  rearward to the floor  128 . The angled portion  136  is angled (i.e., at a non-zero angle) relative to the planar portion  134  and/or the floor  128 . The angled portion  136  provides an impact surface that facilitates upward movement of the under chassis fairing  102  upon contacting (i.e., striking) a road obstacle. Further, the angled portion  136  directs airflow A (see  FIG.  1   ) around and/or underneath the under chassis fairing  102 . In certain embodiments, the front wall  130  is also angled from a center toward the sidewalls  132 A,  132 B, such as to facilitate airflow outward (e.g., to further reduce aerodynamic drag). 
     In certain embodiments, the left sidewall  132 A includes a front left cut-out  140 A and a rear left cut-out  142 A. When the under chassis fairing  102  moves upward, the front left cut-out  140 A at least partially receives the front axle  108 , and the rear left cut-out  142 A at least partially receives the rear axle  110 . A similar configuration is provided in the right sidewall  132 B. Front right cut-out  140 B and rear right cut-out  142 B provide clearance for vertical movement of the under chassis fairing  102 . In certain embodiments, the left sidewall  132 A and the right sidewall  132 B are planar and extend from the front wall  130  to the back edge  138  of the floor  128 . In certain embodiments, the left sidewall  132 A includes steering indentations  143 A on opposing sides of the front left cut-out  140 A, and the right sidewall  132 B includes steering indentations  143 B on opposing sides of the front right cut-out  140 B to provide clearance to accommodate turning the steered wheels. In certain embodiments, the steering indentations  143 A,  143 B are generally M shaped. In certain embodiments, the steering indentations  143 A,  143 B are planar. In other embodiments, the steering indentations  143 A,  143 B include curved portions. In certain embodiments, the cut-outs  140 A,  140 B are offset from the sidewalls  132 A,  132 B within one indentation  143 A,  143 B (e.g., of a semicircle shape). In certain embodiments, the steering indentations  143 A,  143 B are also provided for the rear wheels. 
     In certain embodiments, the front wall  130  and the sidewalls  132 A,  132 B extend upwardly from the floor  128  to the same height. In certain embodiments, upper edges  133 A,  133 B of the sidewalls  132 A,  132 B are parallel to the floor  128 . Further, in certain embodiments, the sidewalls  132 A,  132 B extend rearward to the back edge  138  and maintain a same height from the front edge  137  to the back edge  138 . As the upper edges  133 A,  133 B of the sidewalls  132 A,  132 B are positioned higher than the lower side edge  116  of the vehicle  100 , this overlap ensures that the under chassis fairing  102  extends downwardly from the lower side edge  116  of the vehicle  100  along a length of the vehicle  100  to form a reduced ground clearance RGC (see  FIG.  1   ) which reduces aerodynamic drag of the vehicle  100 . 
     In certain embodiments, the fairing body  122  defines a gap  144  between a left rearward edge  146 A of the left sidewall  132 A and a right rearward edge  146 B of the right sidewall  132 B. This gap  144  allows dust, debris, or any other foreign object that may enter the interior of the under chassis fairing  102  to exit through the gap  144 , thereby preventing accumulation. Further, as the gap  144  is positioned at the rear, the gap  144  does not increase aerodynamic drag. However, in certain embodiments, the fairing body  122  includes a back wall. 
     In certain embodiments, the sidewalls  132 A,  132 B of the under chassis fairing  102  do not extend past the outer surface  112  of the vehicle  100  and are not attached to the outer surface  112  of the vehicle  100 . In certain embodiments, the sidewalls  132 A,  132 B extend up to the outer surface  112  of the vehicle  100 . 
     It is noted that in certain embodiments, the under chassis fairing length UFL of the under chassis fairing  102  (from the front edge  137  to the back edge  138 ) is configured to cover a vehicle length VL of the vehicle  100  (from a front to a rear of the vehicle). In certain embodiments, the under chassis fairing  102  extends from proximate a front of the vehicle  100  past the front axle  108 . In certain embodiments, the under chassis fairing  102  extends from proximate the front of the vehicle  100  past the front axle  108  and at least one of the rear axles  110 . In certain embodiments, the under chassis fairing extends from proximate the front of the vehicle  100  past the front axle  108  and all of the rear axles  110 . For example, in certain embodiments, the under chassis fairing  102  extends from between 50% to 100% of the length of the vehicle  100 , from between 70% to 80% of the length of the vehicle  100 , and/or from between 70% to 90% of the length of the vehicle  100 . In certain embodiments, the under chassis fairing  102  has a length of 5 feet to 30 feet, 10 feet to 25 feet, 15 feet to 20 feet, 10 feet to 15 feet, etc. 
     The under chassis fairing width UFW of the under chassis fairing  102  is configured to cover a vehicle width VW of the vehicle  100 . For example, in certain embodiments, the under chassis fairing  102  extends from between 50% to 100% of the length of the vehicle  100 , from between 70% to 80% of the length of the vehicle  100 , and/or from between 70% to 90% of the length of the vehicle  100 . In certain embodiments, the under chassis fairing  102  has a width of 60 inches to 120 inches, 70 inches to 100 inches, 80 inches to 95 inches, 85 to 90 inches, etc. In certain embodiments, the under chassis fairing  102  is configured to cover a certain footprint of the vehicle  100 . For example, in certain embodiments, the under chassis fairing  102  is configured to cover from between 50% to 100% of the footprint of the vehicle  100 , from between 70% to 80% of the footprint of the vehicle  100 , and/or from between 70% to 90% of the footprint of the vehicle  100 . 
     The front coupling  124  is configured to hang the fairing body  122  from the front axle  108  of the chassis  106  of the vehicle  100 , and the back coupling  126  is configured to hang the fairing body  122  from the rear axle  110  of the chassis  106  of the vehicle  100 . In certain embodiments, the at least one coupling includes at least one of a strap, a telescopic strut, a hook, a bracket (e.g., metal bracket), etc. However, the fairing body  122  could be hung from other parts of the vehicle  100 . 
     In certain embodiments, the front coupling  124  is a bracket (e.g., a U-shaped bracket) including a frontward column  148 , a rearward column  150 , and a crossbeam  152  at a top of and connecting the frontward column  148  and the rearward column  150 . The frontward column  148  is positioned forward of the front axle  108 , and the rearward column  150  is positioned rearward of the front axle  108  such that the front axle  108  is positioned between the frontward column  148  and the rearward column  150 . Such a configuration allows vertical movement of the under chassis fairing  102  relative to the chassis  106  by allowing the front axle  108  to move vertically between and relative to the frontward column  148  and rearward column  150 . Further, such configuration restricts forward/rearward lateral movement of the under chassis fairing  102  relative to the chassis  106  by preventing the front axle  108  from moving laterally past the frontward column  148  and the rearward column  150 . The crossbeam  152  is positioned above the front axle  108  thereby allowing the under chassis fairing  102  to hang by the crossbeam  152 . This also provides a limit to the extended position of the under chassis fairing  102 . 
     In certain embodiments, the front coupling  124  includes at least one guide embodied as a front vertical slot  153  defined in the frontward column  148 . The front vertical slot  153  is configured to receive or engage a portion of the front axle  108  and/or a front guiding component  154  (e.g., nub, pin, etc.) fixedly attached to the front axle  108 . Such a configuration allows vertical movement of the under chassis fairing  102  relative to the chassis  106  by allowing the front guiding component  154  to move within the front vertical slot  153 . Further, such configuration restricts lateral side-to-side movement of the under chassis fairing  102  relative to the chassis  106  by preventing the front guiding component  154  from moving laterally out of the front vertical slot  153  and past the frontward column  148 . In certain embodiments, the fairing body  122  does not extend underneath the front axle  108 . 
     The back coupling  126  includes a frontward column  156  and includes at least one guide embodied as a back vertical slot  158  defined in the frontward column  156 . The vertical slot  158  is configured to receive or engage a portion of the rear axle  110  and/or a back guiding component  160  (e.g., nub, etc.) fixedly attached to the rear axle  110 . The top of the frontward column  156  of the back coupling  126  hangs on the back guiding component  160 . Accordingly, the back coupling  126  also allows for vertical movement of the under chassis fairing  102  while restricting lateral movement. 
     Each of the front vertical slot  153  and the back vertical slot  158  is configured to allow vertical movement and restrict lateral movement of the under chassis fairing  102  relative to the chassis  106 . It is noted that features of the front coupling  124  and the back coupling  126  are interchangeable and that other types of couplings may be used. 
     As a result, upper edges  133 A,  133 B of the left sidewall  132 A and the right sidewall  132 B of the fairing body  122  are positioned at the same height as or higher than the lower side edge  116  of the outer surface  112  of the vehicle  100  so that the left sidewall  132 A and the right sidewall  132 B of the fairing body  122  extend downward from the lower side edge  116  of the outer surface  112  of the vehicle body  104  of the vehicle  100 . In an extended position, the under chassis fairing  102  reduces the ground clearance of the vehicle  100  to increase the aerodynamic profile of the vehicle  100  and reduce aerodynamic drag. Further, the floor  128  and/or sidewalls  132 A,  132 B of the under chassis fairing  102  extend along a length of the vehicle to improve laminar flow past the vehicle  100  and reduce aerodynamic drag. The front and back couplings  124 ,  126  are configured to allow movement of the fairing body  122  from a lowered position vertically toward (and relative to) the chassis  106  upon contact with a road obstacle. In other words, the fairing body  122  is able to move upward toward the vehicle body  104 . 
       FIGS.  2 A- 2 B  are views of another embodiment of the under chassis fairing  102 ′ with non-planar sidewalls  132 A,  132 B. The left sidewall  132 A includes a frontward laterally extended portion  200 A, a frontward laterally recessed portion  202 A, a middle laterally extended portion  204 A, and a rearward laterally recessed portion  206 A. The frontward laterally extended portion  200 A is positioned in front of the front left tire  208 A. The frontward laterally recessed portion  202 A receives the front left tire  208 A therein. The middle laterally extended portion  204 A is positioned between the front left tire  208 A and the back left tire  210 A. The rearward laterally recessed portion  206 A receives the back left tire  210 A therein. The right sidewall  132 B includes similar features which are similarly numbered as the left sidewall  132 A. 
     Such a configuration improves aerodynamic performance as the airflow flows past the frontward laterally extended portion  200 A, the front left tire  208 A, the middle laterally extended portion  204 A, and the back left tire  210 A. As a result, the under chassis fairing  102 ′ covers a greater footprint of the vehicle  100  and extends across a greater width of the vehicle  100  than the under chassis fairing  102  of  FIGS.  1 A- 1 C . 
     In certain embodiments, the under chassis fairing  102 ′ includes couplings that are separate from the guide. In particular, the front coupling is embodied as a U-shaped bracket  124 ′ and the back coupling is embodied as a strap  126 ′. More brackets  124 ′ and/or straps  126 ′ may be used on the front axle and/or the rear axle. 
     The under chassis fairing  102 ′ further includes a pair of frontward columns  148  defining a front vertical slot  153  and a rearward column  150 . Such features prevent frontward/rearward lateral movement and side-to-side lateral movement, as similarly discussed above. 
       FIGS.  3 A- 3 B  are perspective views of the under chassis fairing  102 ′ of  FIGS.  2 A- 2 B  mounted by mechanical joints  300  to a chassis  302 . In other words, the mechanical joint  300  couples the under chassis fairing  102 ′ to the chassis  302  (e.g., frame rails). The mechanical joint  300  includes a first triangular linkage  304 (1) and a second triangular linkage  304 (2). 
     Referring to  FIG.  3 B , the first triangular linkage  304 (1) includes a base end  306 (1) configured to hingedly couple to the under chassis fairing  102 ′ to pivot relative to the under chassis fairing  302 ′ about a first axis A(1). In particular, the hinge coupling restricts the first triangular linkage  304 (1) to one degree of freedom relative to the under chassis fairing  102 ′. The first triangular linkage  304 (1) further includes a vertex end  308 (1) including a first rotational member  310 (1). 
     Similarly, the second triangular linkage  304 (2) includes a base end  306 (2) configured to hingedly couple to the chassis  302  to pivot relative to the chassis  302  about a second axis A(2). In particular, the hinge coupling restricts the second triangular linkage  304 (2) to one degree of freedom relative to chassis  302 . The second triangular linkage  304 (2) further includes a vertex end  308 (2) including a second rotational member  310 (2). 
     The first triangular linkage  304 (1) has three rotational degrees of freedom relative to the second triangular linkage  304 (2) (about the X axis, Y axis, and Z axis). The first rotational member  310 (1) and the second rotational member  310 (2) are rotationally coupled to form a ball joint  312  such that the under chassis fairing  102 ′ is moveable in two translational degrees of freedom (along X axis and Y axis) and restricted in one translational degree of freedom relative to the chassis  302  (along Z axis). The under chassis fairing  102 ′ may move relative to the chassis  302  in five degrees of freedom (translation along X axis and Y axis and rotation about X axis, Y axis, and Z axis), but the under chassis fairing  102 ′ is constrained in one translational degree of freedom (along the Z axis). 
       FIG.  4 A  is a side view of the under chassis fairing  102  of  FIGS.  1 A- 1 C  illustrating under chassis fairing  202  in an extended position as the under chassis fairing  202  approaches a road obstacle  400 . As the under chassis fairing  202  contacts the road obstacle  400 , the angled portion  136  of the front wall  130  and the front  402  of the under chassis fairing  202  move upward. 
       FIG.  4 B  is a side view of the under chassis fairing  202  of  FIG.  4 A  with a front  402  of the under chassis fairing  202  in a retracted position and a rear  404  of the under chassis fairing  202  in the extended position as the under chassis fairing  202  travels over the road obstacle  400 . In particular, the floor  128  of the under chassis fairing  202  contacts the road obstacle  400 . 
       FIG.  4 C  is a side view of the under chassis fairing  202  of  FIG.  4 A  with the front  402  of the under chassis fairing  202  in the retracted position and the rear  404  of the under chassis fairing  202  in the retracted position as the under chassis fairing  202  travels over the road obstacle  400 . 
       FIG.  4 D  is a side view of the under chassis fairing  202  of  FIG.  4 A  with the front  402  of the under chassis fairing  202  in the extended position and the rear  404  of the under chassis fairing  202  in the retracted position as the under chassis fairing  202  travels over the road obstacle  400 . 
     Accordingly, the under chassis fairing  202  reduces aerodynamic drag and portions or all of the under chassis fairing  202  can retract upward upon contact with one or more road obstacles  400 , thereby preserving ground clearance of the vehicle  100 . 
     Those skilled in the art will recognize improvements and modifications to the preferred embodiments of the present disclosure. All such improvements and modifications are considered within the scope of the concepts disclosed herein and the claims that follow.