Patent Publication Number: US-2021179036-A1

Title: Active air scoop

Description:
FIELD OF THE DISCLOSURE 
     The present application relates generally to vehicle air ducts, and more specifically to devices for actively regulating air flow to areas in a vehicle wheel well. 
     SUMMARY 
     The present disclosure is directed to air duct systems for a vehicle, which can include active air scoops. An air duct system for a vehicle can include one or more ducts capable of directing air to a wheel well of a vehicle, and an active air scoop positioned at an inlet of the duct. The air scoop can be configured to control the amount of air flow to the inlet. In some configurations, the air duct can include one or more outlets to the wheel well, including outlets to a low-pressure area of a wheel well and brake components of the vehicle. 
     In some cases, the air duct system can include two or more active air scoops. In some examples, each air scoop can independently control air flow to a respective air duct. In other cases, a single active air scoop can control air flow to two or more branches of a duct (e.g., based on how open the air scoop is). In some cases, the air scoop can sit flush against the underbody of the vehicle when in a closed position. The air duct system can also include one or more valves within an air duct configured to direct the air flow to one or more branches within the duct. 
     In some examples, the operation of one or more active air scoops can be controlled based on the determined temperature in the respective wheel well associated with an active air scoop. For example, an air scoop can be configured to stay open only long enough to cool brake components of a vehicle, but then close when not needed in order to improve aerodynamic efficiency. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       It should be noted that the drawing figures may be in simplified form and might not be to scale. In reference to the disclosure herein, for purposes of convenience and clarity only, directional terms, such as top, bottom, left, right, up, down, over, above, below, beneath, rear, front, distal, and proximal are used with respect to the accompanying drawings. Such directional terms should not be construed to limit the scope of the disclosure in any manner. 
         FIG. 1  is a front view of a vehicle illustrating a stagnation region according to various embodiments. 
         FIG. 2  is a schematic drawing of an underside of a vehicle illustrating high and low pressure areas according to various embodiments. 
         FIG. 3  is a schematic drawing of an underside of a vehicle illustrating high and low pressure areas according to various embodiments. 
         FIG. 4  is a schematic drawing of a portion of a vehicle and a duct according to various embodiments. 
         FIG. 5  is a schematic diagram of a portion of a vehicle and a duct according to various embodiments. 
         FIG. 6  is a schematic diagram of a portion of a vehicle and a duct according to various embodiments. 
         FIG. 7  is a schematic diagram of a portion of a vehicle and a duct according to various embodiments. 
         FIG. 8  is a schematic diagram of a portion of a vehicle and a duct according to various embodiments. 
         FIG. 9  is a schematic drawing of a side view of a vehicle illustrating an active air scoop in a fully extruded positon. 
         FIG. 10  is a schematic drawing of the underbody of a vehicle illustrating a location of an active air scoop. 
         FIG. 11  is a schematic drawing of a side view of a portion of a vehicle depicting an active air scoop, ducting, and wheel well. 
         FIG. 12  is a schematic drawing of a top view of a portion of vehicle depicting two active air scoops, ducting, and wheel well. 
         FIG. 13A  is a schematic drawing of a top view of a portion of a vehicle depicting an active air scoop, ducting, and wheel well. 
         FIG. 13B  is a schematic drawing of a top view of the portion of vehicle depicting an active air scoop, ducting, and wheel well shown in  FIG. 13A . 
         FIG. 14  is a diagram of an exemplary controlled cooling system process. 
     
    
    
     DETAILED DESCRIPTION 
     When a vehicle is in motion, a complex 3-dimensional system of air flow patterns is generated around the vehicle. The flow patterns can be generally grouped as flow past the front of the vehicle, flow over the sides and roof, flow in the gap between a bottom surface of the vehicle and the road, and flow behind the vehicle (wake). These air flow patterns can result in areas or zones of vastly different pressure surrounding the vehicle. Depending on the aerodynamics of the vehicle design, high pressure areas can resist forward movement of the vehicle, and low pressure areas can result in drag that results in forces acting in the direction of the air flow (opposite from the vehicle motion). Both of these resultant forces can either impede the performance of the vehicle, or in the design stage result in the choice of a larger engine to achieve desired performance. In a gasoline or diesel powered vehicle, the resultant forces can decrease the fuel mileage of the vehicle. In an electric vehicle, the resultant forces can decrease the range of the vehicle. 
     At the front of the moving vehicle, when there can be insufficient air flow to direct the air immediately in front of the vehicle around, over or under the vehicle, the velocity of the air can approach zero. At this point, the static pressure can reach a maximum value, referred to as the stagnation pressure. The area where stagnation pressure occurs is referred to as the stagnation region (see, for example,  FIGS. 1 and 2 ). While drag can be most evident at the rear of the vehicle, drag also occurs behind each wheel due the location of the wheels in the air flow region under the vehicle. The blunt cross-sectional shape of the wheels, with respect to the air flow, can create a wake behind each wheel and can result in drag forces imposed on the vehicle. The combination of stagnation pressure at the front of the vehicle and drag behind each of the front wheels can result in a combination of forces detrimental to maintaining forward movement of the vehicle. 
     Additionally, in modern automotive design, wheel wells now house many thermal sinks that are placed there to bleed off excess energy in the form of heat. A non-exhaustive list of such thermal sinks includes: vehicle brakes, oil coolers, radiators, air conditioning heat exchangers, and battery coolant plates. The placement of these thermal sink components in a wheel well that experiences limited air flow can result in the formation of thermal micro climates surrounding individual thermal sinks. These micro climates may act to limit the designed efficiency of those thermal sinks and negatively affect the associated vehicle system. 
     Referring now to  FIGS. 1 and 2 , a vehicle  100  is illustrated according to various embodiments in a front view ( FIG. 1 ) and a bottom view ( FIG. 2 ). As the vehicle  100  is moving forward, a region of high pressure air can build at the front end  110  of the vehicle  100 . Because of the relatively blunt shape of the front end  110 , the region of high pressure air can be trapped leading to a stagnation region  105 . At essentially the same time, as illustrated in  FIG. 2 , regions of low pressure  220  can be created behind each of the front wheels  205  (as used herein, the term “wheel” refers to the rim/tire combination) due to the turbulence created in the air flow around the non-aerodynamic cross-sectional shape of the front wheels  205 . Although generally to a lesser extent, low pressure regions can be created behind each of the rear wheels  210  as well as just behind the back end  215  of the vehicle  100 . 
     As illustrated by the arrows in  FIG. 3 , according to various embodiments, the undesirable forces resulting from the stagnation region  105  and the regions of low pressure  220  can be reduced or minimized by moving air from the stagnation region  105  to the regions of low pressure  220 . Various configurations to move air from stagnation region  105  to regions of low pressure  220  are explained with reference to  FIGS. 4-8  below. Additionally or alternatively, in other examples which will be explained with reference to  FIGS. 10-14  below, the undesirable forces of low pressure  220  can be reduced or minimized by opening one or more active cooling scoops at the underbody of the vehicle. In all examples, the various configurations can also function to cool components within the wheel well, (e.g., the braking system), as will be explained further below. 
       FIG. 4  illustrates a portion of the front end  110  of the vehicle  100  according to various embodiments comprising a duct  405  extending from the front end  110  (e.g., from a front fascia) within the stagnation region  105  to the region of low pressure  220  behind the front wheel  205 . The duct  405  can allow air to flow (as indicated by the dashed arrow) from the stagnation region  105  through a duct inlet  415  and into the duct  405 , exiting the duct  405  out a duct outlet  420  into a wheel well  425 . Removing air from the stagnation region  105  and injecting the air into the wheel well  425  can reduce the pressure of the stagnation region  105  thereby reducing the resistive force at the front end  110  of the vehicle  100 . Injecting the air into the wheel well  425  can increase pressure within the wheel well  425  and reduce or minimize the region of low pressure behind the wheel  205  thereby reducing the drag force acting against the forward movement of the vehicle  100 . In addition, as described in detail below, the air injected into the wheel well  425  by the duct  405  can have a beneficial effect of providing additional cooling to brakes  410 . 
     The duct inlet  415  can comprise any shape conducive to non-turbulent flow of the air through the duct  405 . As such, the duct inlet  415  can be round, oval, rectangular, and the like. The duct inlet  415  can be front facing, or it can be submerged (such as a NACA duct). Although not illustrated in  FIG. 4 , various embodiments can comprise a duct inlet  415  that extends across a large portion of the front end  110 , or the duct inlet  415  can comprise multiple individual inlets  415  that join into the duct  405 . Similarly, the duct outlet  420  can be any shape desired and can comprise one or more baffles (not shown) to direct the exiting air in more than one direction. As illustrated by the various embodiments of  FIG. 4 , the duct  405  can generally narrow from the inlet  415  to the outlet  420  to increase the velocity of the air at the outlet  420 . However, one skilled in the art will readily recognize that the duct  405  can have a generally constant diameter, or cross-sectional area for non-circular ducts  405 . Additionally, the overall shape of the duct  405  can be straight, curved, or any other complex geometry to pass through or around other components of the vehicle  100 . 
       FIG. 5  illustrates various embodiments in which the duct  405  extends further into the wheel well  425  such that the duct outlet  420  is positioned in closer proximity to the region of low pressure  220 . While the embodiments illustrated in  FIG. 5  can more directly affect the region of low pressure, less air can be directed to the brakes  410  for cooling. Therefore, as illustrated in  FIG. 6  according to various embodiments, a second duct  605  comprising a second inlet  610  and a second outlet  615  can be added to the vehicle  100 . The second outlet  615  can be directed toward the brakes  410  to provide cooling. 
     Depending on the structural design of the vehicle  100 , routing the first and second ducts  405 ,  605  through the structure of the vehicle  100  to the wheel well  425  can prove challenging. Therefore,  FIG. 7  illustrates various embodiments in which the duct  405  divides into a first branch  705  to direct a portion of the air flow to the region of low pressure  220  and a second branch  710  to direct a portion of the air flow to the brakes  410  for cooling. The branching of the duct  405  can occur at any point along a length of the duct  405  that is convenient for routing the duct  405  and the first and second branches  705 ,  710 . 
     In various embodiments, the duct  405  can further comprise a valve  715  to regulate the air flow through the duct  405 . The valve  715  can be moveable from a first position in which a maximum air flow is allowed through the duct, to a second position (shown in broken lines) in which the duct  405  is closed or nearly closed, or any position in between. Movement and positioning of the valve  715  can be controlled and directed by a system controller, which in turn can be in communication with an intelligent agent. The intelligent agent can be located within the vehicle  100  or external to the vehicle  100 . In various embodiments, the system control can determine a position of the valve  715  based on input data from one or more sensors (not shown). Exemplary sensors can comprise, but are not limited to, pressure sensors located at any exterior point on the vehicle  100  or within the first or second duct  405 ,  605  or wheel well  425 , temperature sensors in the brakes  410 , ambient temperature sensors, speed sensors, throttle position sensors, and the like. 
     In various embodiments, the valve  715  can be positioned where the first and second branches  705 ,  710  extend from the duct  405  as illustrated in  FIG. 8 . As described above, the system controller can position the valve  715  based on sensor input data. For example, a temperature sensor within the brakes  410  can indicate that the brakes  410  are below an optimum operating temperature. In this situation, the system controller can direct the valve  715  to a position as shown in  FIG. 8  that partially or completely closes the second branch  710 , thereby allowing the temperature of the brakes  410  to rise. If the system controller later determines that the temperature of the brakes  410  is too high, then the valve  715  can be moved to a position as indicated by the broken lines in  FIG. 8  to increase the air flow into the second branch  710 . 
     The valve  715  can be a butterfly valve, a flapper valve, a ball valve, a disk valve, a shutter valve, a gate valve, a globe valve, or any other device known in the art to regulate fluid flow. The valve  715  can, for example, be electrically operated, or hydraulically operated. 
     In other examples, rather than directing airflow from front of air dam as described above with reference to  FIGS. 2-8 , air can be selectively directed to the areas within one or more wheel wells via one or more actuated active cooling scoops. 
       FIG. 9  depicts one embodiment of a vehicle with active cooling scoops  101 . As with the above-described embodiments, an objective of the depicted system is to both limit drag forces on the vehicle and regulate the thermal environment of vehicle components located within a wheel well  103 .  FIG. 9  depicts the deployment of the active cooling scoops  101  to draw air into the vehicle wheel well  103  in order to cool the vehicle components located in that area. Although not shown in  FIG. 9 , the active cooling scoops may alternatively be in a closed position. In the closed position the active cooling scoops  101  can be positioned flush against the underbody of the vehicle, thus providing a low turbulence surface for air to pass over. 
       FIG. 10  depicts the underside of a vehicle according on an embodiment of this disclosure. The active cooling scoops  101  can be situated on the underbody panels  104  of a vehicle and may be situated slightly inboard of the centerline of each vehicle wheel  210 ,  205 . In one embodiment by situating each active cooling scoop  101  slightly forward and to the inboard of each wheel  210 ,  205  a significant cooling advantage may be realized while creating the shortest cooling path for the active brake cooling system. 
       FIG. 11  depicts a detail view of a front wheel well and active cooling scoop according to one embodiment of the invention. For clarity, some elements such as wheel  205  are omitted. The active air scoop  101  is shown in a fully retracted position, with the fully open position indicated by the dotted lines. In one embodiment the active air scoop  101  is hinged at a pivot point on the side closest to the wheel  205  and when actuated it rotates radially along an axis horizontal to the underbody of the vehicle. This hinge  125  may include a spring that biases the movement of the active air scoop  101  toward a closed position. Such a spring may assist in the rapid closing of the active air scoop  101  when it is no longer necessary thus ensuring greater aerodynamic performance. In other embodiments hinge  125  may include a spring that biases the movement of the active air scoop  101  toward opening. In the biased opening embodiment, such a spring may assist in quicker opening of the active air scoop  101  for faster cooling. 
     The active cooling air scoop may be formed from the same material as the underbody of the vehicle. In some embodiments, it may be a pliable or flexible material which can be made of suitable materials to withstand weather and temperature extremes. Such materials include natural and synthetic polymers, various metals and metal alloys, naturally occurring materials, textile fibers, and all reasonable combinations thereof. 
     In further contemplated embodiments of the present disclosure, shape-changing or shape-shifting material can also be used in any of the embodiments. The shape-changing aspect of the disclosure is enabled by hardware comprised of motors and actuators governed by a vehicle dynamic control algorithm in a controller. Shape-changing or smart materials are materials that have one or more properties that can be significantly changed in a controlled fashion by external stimuli, such as stress, temperature, moisture, pH, electric or magnetic fields. 
     The active air scoops  101  are depicted with a fixed outer shape consisting of a flat planar bottom, a straight forward edge, and side walls forming a scoop or channel for air. In a separate contemplated embodiment, each active air scoop  101  has side walls that accordion down such that they form a continuous side wall from the bottom of the scoop to the vehicle underbody. That is, these airflow guiding pieces, each of which has a specific shape, and the pieces may retain their shape whether the pieces are deployed or retracted. In a further contemplated embodiment, any of these guiding pieces can be replaced or augmented by using pliable materials and underlying frames movable by actuators  302  which are governed by a controller  321 . For instance, instead of using an underbody panel  104  made of rigid material, the underbody panel  104  is made of an underlying framework enveloped in the pliable material. By actively controlling the movement and shapes of the underlying frame, one can effectively change the outer contour of this particular underbody panel  104 . The controller can also selectively change the location of the throat section by shifting the contraction fore or aft to modify aerodynamic distribution of front-to-rear wheel  210 ,  205  loading. 
     The active air scoop  101  can be moved using an actuator  302 . The actuator  302  can, for example, be electrically operated, or hydraulically operated. In some embodiments, a rod or cable that is connected to an actuator  302 , and used to move the active air scoop  101 . Each actuator  302  may be configured to open the air scoop through a range of different angles. This opening angle may be selectively chosen to optimally balance the amount of cooling air allowed in while balancing the drag created by opening the active air scoop  101 . At different times, each active air scoop  101  may be opened as required by the local thermal environment of the wheel well that active air scoop  101  is associated with. 
     In one contemplated embodiment, during a hard-turning brake event, the wheel wells  103  on the side facing away from the turn may be cooler and thus require less cooling. The active air scoops  101  on that side of the vehicle may be deployed at a shallow angle relative to the underbody of the car. Conversely the wheel wells  103  on the side of the vehicle closest to the turn may experience greater heat from heavier braking and require significant cooling. The active air scoops  101  may be deployed to a greater angle relative to the underbody of the car on that side. In an emergency braking scenario, high levels of heat may be generated or expected to be generated at all wheel wells  103 . The active air scoops  101  in this situation may be deployed to their fullest deployable angle. 
     Further, movement and positioning of the active air scoop  101  can be controlled and directed by a system controller, which in turn can be in communication with an intelligent agent. The intelligent agent can be located within the vehicle  100  or external to the vehicle  100 . In various embodiments, the system control can determine a position of the active air scoop  101  based on input data from one or more sensors (not shown). Exemplary sensors can comprise, but are not limited to, pressure sensors located at any location in the wheel well  103  on the vehicle underbody  104  or within the duct  405  on any thermal emitting component within the wheel well  103 . These include thermal sensors on the vehicle brakes oil coolers, radiators, and the like. 
     Each active air scoop  101  is connected to its respective wheel well  103  via a duct  405 . The duct inlet  415  can comprise any shape conducive to non-turbulent flow of the air through the duct  405 . This duct inlet is communicatively coupled to the active air scoop  101  and the duct inlet  415  begins at the hinged side of the active air scoop  101 . As such, the duct inlet  415  can be round, oval, rectangular, and the like. The duct inlet  415  is communicatively attached to the active air scoop  101 . Although not illustrated in  FIG. 4 , various embodiments can comprise a duct inlet  415  that extends across a large portion of the active air scoop  101 , or the duct inlet  415  can comprise multiple individual inlets  415  that join into the duct  405 . Similarly, the duct outlet  420  can be any shape desired and can comprise one or more baffles (not shown) to direct the exiting air in more than one direction. In various embodiments, the duct  405  can generally narrow from the inlet  415  to the outlet  420  to increase the velocity of the air at the outlet  420 . However, one skilled in the art will readily recognize that the duct  405  can have a generally constant diameter, or cross-sectional area for non-circular ducts  405 . Additionally, the overall shape of the duct  405  can be straight, curved, or any other complex geometry to pass through or around other components of the vehicle  100 . 
     In some embodiments, duct  405  can extend further into the wheel well  103  such that the duct outlet  420  is positioned in closer proximity to the region of low pressure  220 . In other embodiments, one or more ducts can be utilized to provide air to both brake rotors and region of low pressure  220 .  FIGS. 12-13  illustrate various embodiments in which the active air scoops are configured to selectively provide air to both a brake rotor and a region of low pressure. 
       FIG. 12  illustrates a top view of various embodiments in which a first duct  735  directs a portion of the air flow to the region of low pressure  220  and a second duct  740  directs a portion of the air flow to the brakes  410  for cooling, and air to either duct is determined by active air scoops  501  and  502 . The configuration shown in  FIG. 12  can operate similar to that shown in  FIG. 6  above, however, here, the amount of air directed to low pressure  220  is controlled by a first air scoop  501 , and the amount of air directed to brakes  410  is controlled by a second active air scoop  502 . 
       FIG. 13A-13B  illustrate a respective top view and side view of various embodiments in which an active air scoop  503  controls air flow into duct  745 , which separates into a first branch  750  which can direct air to the region of low pressure  220 , and a second branch  760 , which can direct air to the brakes  410  for cooling. In these illustrations, air scoop  503  is shown in a first (partially opened) position, with a second (fully opened) position indicated in dotted lines. For clarity, wheel  205  is omitted from  FIG. 13B . As illustrated in  FIG. 13B , in some configurations, first branch  750  can be positioned above second branch  760  such that when air scoop  503  is opened to a first position, air is directed primarily to the first branch  750 , and when air scoop  503  is opened to a second position (more open than the first position), air is also directed to the second branch  760 . In other configurations not shown here, first and second branches  750  and  760  may be positioned horizontally with respect to one another. In these configurations, air scoop  503  may be configured to open more widely on one side than the other (e.g., via dual actuators at either vertical wall of the air scoop  503 ), thereby selectively directing airflow to first branch  750  and/or second branch  760 . In still other configurations not shown, the air flow to duct  745  can be controlled via a single air scoop  502 , but the direction of the airflow can be controlled via a valve (e.g., valve  715 ) as similarly described with reference to  FIGS. 7 and 8  above. It should be understood that, although the illustrations above discuss air scoop  503  as only permitting air flow when open, some embodiments may be configured to allow air flow to one or more of the components (e.g., to region of low pressure  220 ) when closed. 
     As with the embodiments described above, movement and positioning of the air scoop (and in some embodiments, valve  715 ) can be controlled and directed by a system controller, which in turn can be in communication with an intelligent agent. The intelligent agent can be located within the vehicle  100  or external to the vehicle  100 . In various embodiments, the system control can determine a position of the valve  715  based on input data from one or more sensors (not shown). Exemplary sensors can comprise, but are not limited to, pressure sensors located at any exterior point on the vehicle  100  or within the first or second duct  405 ,  605  or wheel well  425 , temperature sensors in the brakes  410 , ambient temperature sensors, speed sensors, throttle position sensors, and the like. 
     One or more temperature sensors may be implemented in some embodiments of this disclosure. A thermocouple may be placed in direct contact with some part of the brake system located in a wheel well. In one embodiment, this sensor is a thermocouple that is placed on a surface that is not in the direct path of any cooling air that may be introduced when the active air scoop  101  is deployed. By keeping the thermocouple out of the direct path of cooling air a more accurate thermal reading may be made. In other embodiments, a number of thermocouples are placed both on various vehicle brake components and on other thermal sources in the wheel well. 
     In another contemplated embodiment one or more IR sensors may be used to detect the temperature of individual components in the wheel well. An IR sensor may be placed in direct line of site with the brake rotor, brake caliper, brake line, or another brake part. The use of multiple IR detectors or a single IR detector that is mechanically targeted at multiple thermal points is also contemplated. 
     Additionally, brake system temperature may be modeled on existing vehicle inputs such as vehicle speed, brake pressure, brake force applied over a given time, and other similar vehicle data points. Known brake algorithms may be used to calculate the change in kinetic energy of the vehicle. The change in the kinetic energy of the vehicle over a given time may be used to calculate the amount of kinetic energy absorbed by the vehicle&#39;s brakes. Known algorithms may be used to estimate the temperature of a vehicle&#39;s brake system after it has absorbed a calculated amount of kinetic energy. As such, a vehicle&#39;s brake temperature may be estimated without directly measuring the temperature of a vehicles brake system. 
     In some embodiments, the active air scoops are managed independently. Thus, when the thermal components located in a wheel well do not need additional cooling, the active air scoop is not deployed. However, if cooling is needed by one more thermal components in a wheel well, then the active air scoop is deployed. 
       FIG. 14  depicts an exemplary intelligent predictive computer controlled cooling system process. This system is managed by a vehicle&#39;s master braking system. In one contemplated embodiment, a brake management system (not shown) is configured to control an actuator that controls one or more active air scoops  101 . The brake management system may be further configured to receive input from one or more thermal detection devices located within a vehicle wheel well. The brake management system may be programed to compare the temperature reported by a thermal detection device with a programed thermal limit for a device or the wheel well environment. If the temperature reported by the thermal device exceeds that known thermal limit, then the brake management system may command the actuator to open one or more active air scoops. 
     It will be understood that the active air scoops may be opened fully or to a partial opened state depending on the commands from the brake management system. In one embodiment, the brake management system receives a thermal signal indicating the wheel well  103  temperature is above a thermal limit. The brake management system commands an actuator to open the active air scoop  101  associated with that wheel well to a half way open position. The brake management system then waits a prescribed period of time, which in some cases may be between 5 and 60 seconds. If the temperature in that wheel well is still above a thermal limit after the prescribed period has passed, then the brake management system may command an actuator to open the active air scoop to a fully open position. If the temperature in that wheel well falls below the thermal limit at any point, then the brake management system may command an actuator to close the active air scoop. 
     It will be understood by those skilled in the art that the brake management system described herein may be the vehicle&#39;s primary braking system or it may be a subsystem within a vehicle braking system. In other contemplated embodiments, the brake management system described herein as the control system for the active air scoops may be a separate system from the rest of the vehicle&#39;s braking system. 
     While the present disclosure has been described in connection with a series of preferred embodiments, these descriptions are not intended to limit the scope of the disclosure to the particular forms set forth herein. The above description is illustrative and not restrictive. Many variations of the embodiments will become apparent to those of skill in the art upon review of this disclosure. The scope of this disclosure should, therefore, be determined not with reference to the above description, but instead should be determined with reference to the appended claims along with their full scope of equivalents. 
     As used herein, the term “vehicle” refers to any land vehicle, motorized, electric, and hybrid. It also includes all vehicle types, including sedans, sports cars, station wagons, sports utility vehicles, trucks, vans, and tractor trailers. 
     As used herein, the terms “retracted” and/or “retractable” in conjunction with the ability for an airflow guiding piece to move, refer to a motion of retrieving the guiding piece back toward the vehicle&#39;s underbody, as opposed to moving away from the vehicle and toward the ground. It should be noted that these terms do not define how the guiding pieces are retrieved, and they do not define in what direction the guiding pieces are retrieved. For example, to “retract” an active air scoop, the motion can include pivoting the active air scoop in almost a rotating action along a longitudinal side of the side skirt. Likewise, to “retract” a side skirt can also include the motion of lifting the side skirt in a vertical direction toward the underbody without rotating the side skirt along its longitudinal side. 
     As used herein, the terms “having”, “containing”, “including”, “comprising”, and the like are open ended terms that indicate the presence of stated elements or features, but do not preclude additional elements or features. The articles “a”, “an” and “the” are intended to include the plural as well as the singular, unless the context clearly indicates otherwise.