Abstract:
An air deflector assembly for a vehicle includes a vertically translatable air deflector and linear actuators actuated in series by a driver to vertically translate the air deflector. The air deflector includes one or more rails configured for sliding translation within one or more cooperating vehicle-mounted tracks. A controller is operatively connected to the driver, and may be configured to vertically translate the air deflector to a predetermined position according to a vehicle rate of travel. The driver selectively causes the linear actuators to raise or lower the air deflector.

Description:
TECHNICAL FIELD 
       [0001]    This disclosure relates generally to airflow control for motor vehicles. In particular, the disclosure relates to an airflow control assembly for controlling deployment of an air deflector. 
       BACKGROUND 
       [0002]    As the speed at which a motor vehicle travels increases, because of differences in airspeed and pressure generated underneath the vehicle chassis relative to the top of the vehicle, lift is generated and contact of the vehicle wheels with the road surface decreases slightly. This can affect handling and stability, particularly for vehicles being operated at higher speeds. To address this problem it is known to provide aerodynamic air deflectors or “air dams” for motor vehicles, to assist in managing airflow passing beneath the vehicle. By use of such air deflectors, motor vehicle fuel efficiency can be improved. Likewise, air deflectors assist in limiting motor vehicle lift. For example, vehicle front air dams limit motor vehicle front end lift by creating a down-force, forcing the vehicle nose down and so improving vehicle handling and stability. Still more, properly designed front air dams may assist in engine cooling and therefore efficiency. Other air deflectors such as spoilers can provide a similar effect, for example by creating a down force near a vehicle rear end to improve rear wheel contact with a road surface. 
         [0003]    Of necessity, air deflectors extending below the motor vehicle chassis reduce ground clearance. This may be of little import when the vehicle is traveling on a smooth road. However, when the vehicle is travelling on a rough road, excessive reduction in ground clearance may result in vehicle damage and potentially a loss of stability and handling. For example, even if the vehicle does not actually strike an obstacle in the road, sudden braking or steering may cause the vehicle nose to dip or roll, in turn causing a portion of a front air dam to strike the road surface and cause damage and potential impairment of vehicle stability and handling. Moreover, at lower speeds the air deflector may not be needed to improve fuel efficiency and handling, and retraction of the air deflector may be desirable. 
         [0004]    To solve this and other problems, the present disclosure relates to a compact and efficient system for deploying and retracting a motor vehicle air deflector. 
       SUMMARY 
       [0005]    In accordance with the purposes and benefits described herein, in one aspect of the disclosure an airflow control assembly for a vehicle is described, comprising a vertically translatable air deflector and a plurality of linear actuators actuated in series by a driver to vertically translate the air deflector. The air deflector comprises one or more rails configured for sliding translation within one or more cooperating vehicle-mounted tracks. In embodiments, the one or more rails are configured as T-channel sliders and the cooperating tracks define corresponding female receivers. A controller may be operatively connected to the driver. In embodiments, the driver may be a fluid driver. 
         [0006]    In embodiments, the controller comprises logic including executable instructions to cause vertical translation of the air deflector to a predetermined position according to a vehicle rate of travel. In embodiments, the driver is a hydraulic pump which may be reversibly operated to selectively cause the plurality of linear actuators to raise or lower the air deflector. In embodiments, each of the plurality of linear actuators is a hydraulic piston, the plurality of linear actuators in combination with the hydraulic pump defining a hydraulic circuit. 
         [0007]    In the following description, there are shown and described embodiments of the disclosed air deflector assembly and of an airflow control system. As it should be realized, the devices and systems are capable of other, different embodiments and their several details are capable of modification in various, obvious aspects all without departing from the devices as set forth and described in the following claims. Accordingly, the drawings and descriptions should be regarded as illustrative in nature and not as restrictive. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    The accompanying drawing figures incorporated herein and forming a part of the specification, illustrate several aspects of the disclosed air deflector assembly, and together with the description serve to explain certain principles thereof. In the drawings: 
           [0009]      FIG. 1  shows a vehicle including a front air dam; 
           [0010]      FIG. 2  shows an active air deflector according to the present disclosure; 
           [0011]      FIG. 3  shows in isolation an air deflector-mounted rail and cooperating vehicle-mounted track for the active air deflector if  FIG. 2 ; 
           [0012]      FIG. 4  shows a linear actuator for actuating the air deflector for vertical translation by the rail and cooperating track of  FIG. 3 ; 
           [0013]      FIG. 5  is a schematic depiction of an airflow control assembly according to the present disclosure; 
           [0014]      FIG. 6  is a schematic depiction of a control system for the airflow control assembly of  FIG. 5 ; and 
           [0015]      FIG. 7  is a flow chart depicting control logic for controlling the airflow control assembly of  FIG. 5  via the control system of  FIG. 6 . 
       
    
    
       [0016]    Reference will now be made in detail to embodiments of the disclosed air deflector assembly and airflow control system, examples of which are illustrated in the accompanying drawing figures. 
       DETAILED DESCRIPTION 
       [0017]    Preliminarily, the present disclosure describes a vehicle air deflector primarily in the context of a front-mounted air deflector for altering air flow beneath/around a vehicle chassis, specifically a front air dam. However, the skilled artisan will appreciate that the disclosed systems and devices are readily adaptable to other types of vehicle air deflector, including without intending any limitation fender flares, side skirt cribs, top and/or rear spoilers, and others. Application of the presently described devices and systems to all such embodiments is contemplated herein. 
         [0018]    With reference to  FIG. 1 , as described above it is known to provide a motor vehicle  100  including a translatable aerodynamic front air deflector  120  disposed substantially adjacent and behind a vehicle bumper  140  and deployable downwardly from the vehicle to control airflow (see arrows) below the vehicle  100 . The air dam  120  reduces airflow below the vehicle, thereby reducing the tendency of the nose of the vehicle to lift when traveling at speed. Likewise, by use of translatable air dams  120  having a variety of configurations, airflow below the vehicle can be increased or decreased as needed to assist in cooling underbody components. 
         [0019]    However, such translatable air deflector systems can be unduly complex and costly. To solve this and other problems, with reference to  FIG. 2  there is shown a vehicle air deflector assembly  200  according to the present disclosure, associated with a vehicle bumper  202 . The assembly  200  includes a driver  204  configured to actuate a plurality of linear actuators  206  in series, i.e. as a unit, to vertically translate an air deflector  208  (arrows A). 
         [0020]    The air deflector is configured for vertical translation by one or more air deflector-mounted rails  210  configured to be slidingly received by one or more cooperating vehicle mounted tracks (not shown in this view). In an embodiment (see  FIG. 3 ), the air deflector-mounted rails  210  are configured as T-channel sliders, and the vehicle-mounted tracks define cooperating female receivers therefore on a vehicle surface, for example cooperating tracks  300  associated with the vehicle belly pan  302 . However, it will be appreciated that other configurations for rails  210  and tracks  300  are possible, and contemplated for use herein. 
         [0021]    In an embodiment (see  FIG. 4 ), each linear actuator  206  includes a piston head  400  coupled to a drive shaft  402  which in turn is operationally coupled to the air deflector  202 . The piston head  400  is received in an interior chamber  404  such that an upper chamber  406  and a lower chamber  408  are defined. The upper chamber  406  includes an inlet  410   a  and the lower chamber  408  includes an inlet  410   b , allowing placing the upper and lower chambers  406 ,  408  in fluid operational communication with the driver  204  (not shown in this view). As will be appreciated and further described below, supplying a driving fluid to the upper chamber  406  via inlet  410   a  will displace the piston head  400  downwardly, causing the air deflector  202  to deploy by likewise translating vertically downwardly. Conversely, supplying a driving fluid to the lower chamber  408  via inlet  410   b  will displace the piston head  400  upwardly, causing the air deflector  202  to retract by likewise translating vertically upwardly. 
         [0022]    In embodiments, a distance traveled by the air deflector  208  when deploying is determined by a stroke length of the piston head  400 /drive shaft  402 . 
         [0023]    The piston head  400  may include a seal  412  for controlling a fluid leakage between upper chamber  406  and lower chamber  408 . In embodiments, a seal  412  is selected which allows a limited fluid leakage between upper chamber  406  and lower chamber  408 , which as will be appreciated provides a self-bleeding function to remove air from the high pressure side of the piston head  400 . 
         [0024]    In the depicted embodiment, driver  204  is a fluid driver such as a reversible hydraulic pump supplied by a reservoir  500  with a suitable hydraulic fluid  502 . As shown, the reversible hydraulic pump driver  204  includes two fluid outlets  504   a ,  504   b . Fluid outlet  504   a  is in serial fluid communication with each actuator inlet  410   a , and fluid outlet  504   b  is in serial fluid communication with each actuator inlet  410   b , such as by suitable hoses  506 . Thus, as will be appreciated the hydraulic pump  204  motor may be actuated in a first direction to supply fluid to hydraulic actuators upper chambers  406  to vertically translate piston head  400  and thereby air deflector  208  downwardly. By reversing the polarity of the motor, fluid is supplied to hydraulic actuators lower chambers  408  to vertically translate piston head  400  and thereby air deflector  208  upwardly. 
         [0025]    A representative control system  600  is shown in  FIG. 6 . As shown, the system includes a power source  602  such as a vehicle battery, in electrical communication with the driver  204  and a controller  604 . The controller may be any suitable existing or supplied controller or microcontroller. In the depicted embodiment, the controller  604  is the vehicle Body Control Module (BCM), which is already advantageously adapted and adaptable for controlling a variety of vehicle systems. As shown, the power source  602  and controller  604  are in electrical communication with the driver  204 , for operating the driver reversibly as summarized above. 
         [0026]    In turn, the controller  604  is provided with logic for controlling operation of the driver  204  according to a variety of inputs. The logic may include computer-executable instructions for operating the driver  204  in a first direction and in a second direction based on an input from a vehicle system  606 . In the depicted embodiment of  FIG. 6 , the controller  604  is configured for receiving an input from the vehicle speedometer  606 . At a high level, as the vehicle  100  reaches a predetermined speed, the controller  604  on receiving the input from the speedometer  606  that the predetermined speed has been reached or exceeded issues a signal to the driver  204  to perform a predetermined operation of actuating the linear actuators  206  to vertically translate the air deflector  208  (not shown in this view) as needed. 
         [0027]    A representative control logic  700  flow is shown in  FIG. 7 . In the depicted example, deployment of the air deflector  208  is controlled by a vehicle  100  speed, and therefore the configuration of the control system  600  is substantially as depicted in  FIG. 6 . At a Start point (step  700 ), for example when the vehicle  100  motor is started, the system is activated. At step  702  a determination is made whether the vehicle  100  is traveling at a first preset speed, such as by input provided from the speedometer  606  to the controller  604 . If so, at step  704  a command is issued leading to a delayed deployment of the air deflector  208 , for example by initiating a 10 second timer included in the controller  604  logic. In one non-limiting example, the first preset speed could be 40 miles/hour, indicative that the vehicle is accelerating to a speed wherein deployment of an air dam  208  would be beneficial to fuel economy, motor cooling, etc. 
         [0028]    In addition to or in place of step  704 , logic  700  may include a step  706  of determining whether the vehicle  100  is traveling at a second preset speed, such as by input provided from the speedometer  606  to the controller  604 . If not, the timer initiated at step  704  continues to run. If so, at step  708  a command is issued causing deployment of the air deflector  208 . As will be appreciated, the deployment of air deflector  208  occurs by a command issued by controller  604  actuating driver  204  to supply fluid to first chambers  406  of linear actuators  206  via inlets  410   a , thus causing deployment of air deflector  208  as described above. In one non-limiting example, the second preset speed could be 50 miles/hour, being a speed at which it has been determined that deployment of an air dam  208  would be beneficial to fuel economy, motor cooling, etc. 
         [0029]    Likewise, the system  700  is configured to retract the air deflector  208  at need. In the embodiment depicted in  FIG. 7 , at step  710  a determination is made whether the vehicle  100  speed has decreased to at or below the second preset speed, again such as by input provided from the speedometer  606  to the controller  604 . If not, the air deflector  208  remains deployed. If so, at step  712  a command is issued leading to a delayed retraction of the air deflector  208 , for example by initiating a 10 second timer included in the controller  604  logic. Vehicle  100  speed decreasing to the second preset speed would serve as an indicator that the vehicle is approaching rough ground necessitating retraction of the air deflector  208 , or that the vehicle is decelerating to a speed where deployment of the air deflector is not beneficial. 
         [0030]    In addition to or in place of step  712 , logic  700  may include a step  714  of determining whether the vehicle  100  speed has decreased to at or below the first preset speed, again such as by input provided from the speedometer  606  to the controller  604 . If not, the timer initiated at step  712  continues to run. If so, at step  716  a command is issued causing retraction of the air deflector  208 . As will be appreciated, the retraction of air deflector  208  occurs by a command issued by controller  604  actuating driver  204  to supply fluid to second chambers  408  of linear actuators  206  via inlets  410   b , thus causing retraction of air deflector  208  as described above. Vehicle  100  speed decreasing to the first preset speed would serve as an indicator that the vehicle has encountered rough ground necessitating retraction of the air deflector  208 . Alternatively, at the first preset speed it may have been determined that deployment of the air deflector is not beneficial. 
         [0031]    Of course, the above parameters are presented as examples only, and are not to be taken as limiting. For example, the first and second preset speeds, the timer delays, etc. can be adjusted as needed in accordance with the vehicle type, capacity of the driver  204  and air deflector  208 , and in accordance with other parameters. 
         [0032]    Thus, by the above-described structures and mechanisms, an airflow control assembly and system are provided for raising and lowering of an air deflector in accordance with a vehicle speed and other parameters. The system is simple, robust, and efficient, requiring only a single driver  204  for operation and controllable from existing vehicle controllers provided input from existing vehicle systems such as the speedometer. Obvious modifications and variations are possible in light of the above teachings. All such modifications and variations are within the scope of the appended claims when interpreted in accordance with the breadth to which they are fairly, legally and equitably entitled.