Abstract:
A retractable air dam assembly for a vehicle is provided. The air dam assembly has an air deflector panel adapted to be mounted adjacent a front bumper of a vehicle. A linear actuator is adapted to be mounted to the vehicle. At least one rocker arm is adapted to be mounted to the vehicle, and coupled to the linear actuator at a first end, and coupled to the panel at a second end. The linear actuator translates the panel linearly between a stowed position, in which the panel is at least partially concealed by the front bumper, and a deployed position, such that the panel at least partially extends a distance below a bottom surface of the front bumper to reduce airflow beneath the vehicle. A counter-balance is connected to a third end of the rocker arm to offset a weight of the panel.

Description:
TECHNICAL FIELD 
     The present disclosure relates to aerodynamic front air dams for automotive vehicles. 
     BACKGROUND 
     Aerodynamic airflow considerations are a priority of vehicle body design. Effective airflow management over a vehicle body can be critical in meeting functional demands for passenger compartment acoustics, fuel efficiency and safety of passenger type vehicles. Aerodynamic design also enhances vehicles control and improves speed of passenger vehicles. Front air dams are a common aerodynamic feature used to controls airflow around the vehicle and limit front end lift and create down-force. 
     SUMMARY 
     In one embodiment, a retractable air dam assembly for a vehicle is provided. The air dam assembly has an air deflector panel adapted to be mounted adjacent a front bumper of a vehicle. A linear actuator is adapted to be mounted to the vehicle. At least one rocker arm is adapted to be mounted to the vehicle, and coupled to the linear actuator at a first end, and coupled to the panel at a second end. The linear actuator translates the panel linearly between a stowed position, in which the panel is at least partially concealed by the front bumper, and a deployed position, such that the panel at least partially extends a distance below a bottom surface of the front bumper to reduce airflow beneath the vehicle. A counter-balance is connected to a third end of the rocker arm to offset a weight of the panel. 
     In one other embodiment, a vehicle is provided. The vehicle includes a front bumper mounted to a vehicle frame. An air deflector panel is mounted for translation relative to the vehicle frame adjacent to the front bumper. A linear actuator is operably connected to the panel and the vehicle frame to move the panel in a generally vertical direction between a stowed position, and a deployed position. In the deployed position, the panel extends below the bumper to reduce airflow beneath the vehicle. 
     In one further embodiment a deployable air dam assembly for a vehicle is provided. The deployable air dam assembly includes an air deflector panel adapted to be mounted to a vehicle. A linear actuator is operably connected to the panel and adapted to be mounted to a vehicle. The linear actuator is adapted to move the panel substantially in a linear direction between a stowed position and a deployed position to reduce airflow beneath the vehicle. 
     In another embodiment, the deployable air dam assembly also includes a sensor and a controller. The controller is in communication with the sensor and the linear actuator. The controller is configured to actuate the linear actuator between the stowed position and the deployed position based on a sensor signal. 
     In another embodiment, the sensor signal includes a speed signal indicative of a vehicle speed and the controller commands the linear actuator to deploy the panel as the vehicle speed increases. 
     In another embodiment, the sensor signal includes a navigation signal and the controller commands the linear actuator to retract the panel based on the navigation signal. 
     In another embodiment, the panel has a convex profile in a transverse direction. 
     In another embodiment, the air deflector panel has a deflection surface oriented substantially vertical in both the stowed and deployed position. 
     In another embodiment, the deployable air dam assembly also includes a rocker arm coupled to the linear actuator at a first end. A counter-balance is connected to a second end of the rocker arm to offset a weight of the panel. 
     In another embodiment, the deployable air dam assembly also includes a transverse pivot shaft. The rocker arm pivots the pivot shaft as the linear actuator pivots the rocker arm. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side view of a front portion passenger vehicle including a deployable air dam illustrated in a stowed position, in accordance with an embodiment of the present disclosure; 
         FIG. 2  is the side view of the front portion passenger vehicle illustrating the deployable air dam in a deployed position; 
         FIG. 3  is a front perspective view of the vehicle cut-away in order to illustrate a portion of a deployable air dam assembly; 
         FIG. 4  is a front perspective view of a portion of the deployable air dam assembly of  FIG. 3 ; and 
         FIG. 5  is a side view of a portion of the deployable air dam assembly of  FIG. 3 . 
     
    
    
     DETAILED DESCRIPTION 
     As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention. 
     A front air dam is typically found on the front-end of a vehicle and appears as an extension to the bottom of the front bumper. Typically, the air dam is rigid and extends parallel to the ground and is attached to the bumper with support rods to ensure the front air dam remains parallel to the ground. 
     Depending on its positioning, a front air dam can limit how much air is directed under the vehicle by slicing through the incoming air stream and directing a portion of the airflow over the vehicle body. A front air dam can helpful in preventing front end lift as well as providing downward force on the vehicle. The overall reduced lift and increased down force is created by the air dam restricting airflow along the underbody of the vehicle. 
     To understand how a typical air dam prevents lift and creates downward force it is helpful to understand the fluid dynamics as oncoming air approaches the front of a vehicle. When oncoming air reaches the front of the vehicle it must come to a stop before it turns to move either up and over, down and under, or around the vehicle. Thus the front of the moving vehicle is an area of relatively high pressure. 
     The relatively high pressure at the front of a moving vehicle pushes back on the vehicle creating drag. The typical front air dam extends below the bumper close to the road and air flowing underneath the front air dam and vehicle creates somewhat of a Venturi effect, based on Bernoulli&#39;s equation, where pressure is decreased as air is forced through a constriction and speeds up in velocity. Thus the region between the air dam and the pavement is an area of low pressure. This adds up to a downward force on the air dam. 
     The resultant dynamic downward force generally helps the driver to retain control of the vehicle at higher road speeds. A front air dam is typically associated with racing vehicles. However, the aerodynamic principles also apply to passenger vehicles. But there are several factors which limit a typical front air dam&#39;s aerodynamic effectiveness on a passenger vehicle. Additionally, front air dams for passenger vehicles must be to have adequate ground clearance to accommodate suspension and body movement over dips and potholes, which makes typical air dams aerodynamically effective. 
     Utility vehicles, such as sport utility vehicles and pickup trucks, have also been popular in recent years. As utility vehicles have become popular for utilization as passenger vehicles, manufacturers of utility vehicles have incorporated many features into utility vehicles to enhance fuel efficiency, safety and control at high speeds. 
     Utility vehicles are often designed for travel through rough terrain. Additionally, utility vehicles are generally designed to haul cargo, whether in a cargo compartment, a bed of the vehicle, or by towing cargo with a trailer. In order to meet these extreme design requirements, utility vehicles are often provided with a vehicle body that is elevated greater than conventional passenger vehicles. In order to meet the fuel efficiency and safety standards while maintaining the elevated cargo compartments in utility vehicles, front end airflow management of utility vehicles is required. 
       FIG. 1  and  FIG. 2  illustrate a side perspective view of a passenger vehicle  10  including a front air dam panel  12  according to an embodiment of the present disclosure. In  FIG. 1 , the air dam panel  12  is raised up to a stowed position.  FIG. 2  illustrates the air dam panel  12  in a deployed position where the air dam is lowered. 
       FIGS. 1 and 2  illustrate the front end  14  of the vehicle  10  that is a truck or sport utility vehicle having a vehicle body  16  elevated relative to an underlying support surface  18  upon which the vehicle  10  travels. 
     The front end  14  of the vehicle  10  includes an area forward of a passenger compartment in the longitudinal direction. As illustrated in  FIG. 1 , the front end  14  includes a hood  26  defining an engine compartment  28  there beneath. The front end also includes front quarter panels  30  on opposed lateral sides of the vehicle  10 . Each quarter panel  30  defines a front wheel well  32  is illustrated on a right side of the vehicle  10 . The left quarter panel is generally a mirror image. The engine compartment  28  is located laterally between the quarter panels  30 . 
     The front end  14  also includes a front fascia  34 . The front fascia  34  is generally located forward of the hood  26  and quarter panels  30 . The front fascia  34  includes the front grille  36  and the bumper  38 . The front grille  36  defines an opening to the engine compartment  28  in order to allow airflow into the air induction system and for cooling of the engine compartment  28 . The grille  36  may be designed for vehicle styling and aesthetic appeal and may also include the vehicle manufacturer logo or may have ornamental design characteristics. 
     The bumper  38  provides energy absorption in the event of a front impact crash. As illustrated, the bumper  38  may extend forward of the grille  36 . However, in other embodiments, the bumper  38  may be generally flush with the grille  36 . 
     As shown in  FIG. 2 , in the deployed position, the air dam panel  12  is moved downward in the vertical direction in order to prevent airflow beneath the vehicle. In the deployed position, the front air dam panel  12  may extend an additional distance below a lower surface  40  of the bumper  38  or the front fascia  34 . The air dam panel  12  may be offset from the front bumper  38  so that the air dam panel  12  is not flush with the bumper  38  in the vertical direction. 
     Unlike typical air dams which extend from the bumper and are located close to the ground to prevent air from flowing underneath the vehicle, trucks and utility passenger vehicles like those illustrated in  FIGS. 1 and 2  must maintain a minimum ground clearance in order to prevent colliding with obstacles under certain road condition. Therefore, the front air dam panel  12  can be moved to the deployed position illustrated in  FIG. 2  when road conditions are determined to be safe. 
     A deployable air dam assembly  50  may also include an air dam controller  54  to automatically actuate the air dam panel  12  between the deployed position and the stowed position. In the deployed position, the air dam panel  12  is lowered to a closer distance to the driving surface. The air dam panel  12  prevents some of the air from flowing beneath the vehicle and along the vehicle underbody by redirecting flow around the vehicle instead. In the stowed position, the air dam panel  2  is located substantially above the driving surface  18  and does not generally redirect airflow. 
     The air dam panel  12  may be capable of being positioned at many different deployed positions based on vehicle speed or environmental conditions, for example. The air dam controller  54  may control the deployed position of the air dam panel  12  based on speed or road obstacles. For example, the air dam panel  12  may be raised to the stowed position if the vehicle is being driven at lower speeds where there is not large drag, or if an obstacle is detected that could potentially damage the air dam panel  12  is detected by a vehicle sensor  56 . 
     The vehicle sensor  56  may be any type of device used for detecting distance between the vehicle  10  and an externally located object, such as radar, a camera, LIDAR or even vehicle-to-vehicle communication. The vehicle  10  may also include sensors for detecting uneven road conditions though vibration sensors or sensors associated with the suspension system, for example. The vehicle sensors  56  are in communication with the air dam controller  54  and provide data signals to the controller  54 . 
     Alternatively, a navigation system may indicate that a terrain of a given road is too rough to safely deploy . . . . 
       FIGS. 3-6  illustrate the deployable air dam assembly  50  in more detail.  FIG. 3  illustrates the front end  14  being partially cut-away to show a portion of the deployable air dam assembly  50  as it is mounted in the vehicle  10 . 
     The deployable air dam assembly  50  is mounted to a vehicle frame  58 . The vehicle frame  58  is disposed inboard of the front fascia  34  and the bumper  38 . Likewise, the front fascia  34  and bumper  38  may also be mounted to the vehicle frame  58 . As shown in  FIG. 3 , the air dam panel  12  may be positioned adjacent an inboard side  62  of the front fascia  34  and the bumper  38 . The air dam panel  12  is also positioned below the grille  36  in the vertical direction. Even in the stowed position, the air dam panel  12  may not extend across the grille  36  openings so the airflow to the engine, for example, is not inhibited. 
     Turning now to  FIG. 4 , the deployable air dam assembly  50  is shown in more detail. The deployable air dam assembly  50  includes a central linear actuator  60 . However any suitable number of linear actuators  60  is contemplated. The linear actuator  60  may be any sort of actuator which moves substantially along one plane or creates motion in a straight line. For example, the linear actuator  60  may be an electric motor-driven actuator, a pneumatic or hydraulic cylinder, a telescoping actuator, screw actuator or linear slide actuator. 
     The linear actuator  60  provides advantages over other actuators. For example, the linear actuator  60  is relatively inexpensive and a simple design which is repeatable and durable. The linear actuator  60  may also be capable of high speeds to extend and retract the air dam panel  12  quickly if obstructions are detected in the road. Additionally, the linear actuator  60  is extendable to incremental positions to select a desired extension for a particular speed in order to optimize efficiency. As illustrated in the figures, the deployable air dam assembly includes at least two guide shafts  72  connected to the air dam panel  12  and supported by guide sleeves  73  with internal bearing assemblies upon the vehicle frame  58 . The guide shafts  72  are lightweight and strong. Linear movement of the air dam panel  12  also allows the panel  12  to be positioned in multiple deployed positions while still maintaining an air deflection face  64  substantially vertical and perpendicular to the direction of travel to provide the greater air deflection. 
     The deployable air dam assembly  50  also includes a rocker arm  66 . The rocker arm  66  pivots about a transverse pivot shaft  68  mounted to the frame  58 . The transverse shaft  68  is offset from and parallel to the frame  58 . The transverse shaft  68  is mounted to the frame  58  with brackets  70 . The brackets  70  include apertures with bearing assemblies so that the transverse shaft  68  pivots with respect to the brackets  70 . 
     The transverse pivot shaft  68  extends through the center of the rocker arm  66 , however the transverse shaft  68  may be connected anywhere along the rocker arm  66 . The rocker arm  66  is connected to the linear actuator  60  at a first end  74  and is connected to a counter-balance weight  76  at a second end  78 . 
     The counter-balance weight counteracts the weight of the air dam panel  12 . The counter-balance weight  76  reduces the force required by the linear actuator  60  thereby reducing the size of the linear actuator  60 . The counter-balance weight  76  also aids the linear actuator  60  in moving the air dam panel  12  quicker from the deployed position to the stowed position. 
     As illustrated in the Figures, the deployable air dam assembly  50  may have only one counter-balance weight  76  connected to a central rocker arm  66 . However, any number of rocker arms  66  and counter-balance weights  76  are contemplated. The deployable air dam assembly  50  also includes a lever arm  80  connected to the guide shaft  72  at a first end  84  and driven by transverse pivot shaft  68  at a second end  82 . 
     The deployable air dam assembly  50  also includes a connector  90  for connecting the guide shaft  72  to the air dam panel  12 . The deployable air dam assembly may include multiple connectors  90  for connecting each of the guide shafts  72  to the air dam panel  12 . Each of the connectors  90  may have a different shape or dimension since the air dam panel  12  may have a convex profile curvature that may not be parallel to the vehicle frame  58  to which the guide shaft  72  is mounted. 
     While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention. Additionally, the features of various implementing embodiments may be combined to form further embodiments of the invention.