Patent Publication Number: US-11639204-B2

Title: Aerodynamic system for vehicles and methods for operating the same

Description:
RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application Ser. No. 63/019,939, filed May 4, 2020, entitled AERODYNAMIC SYSTEM FOR VEHICLES AND METHODS FOR OPERATING THE SAME, the entire disclosure of which is herein incorporated by reference. 
    
    
     FIELD OF THE INVENTION 
     The present application relates to an aerodynamic system for vehicles and methods for operating the same, in particular fairing systems and/or assemblies. 
     BACKGROUND OF THE INVENTION 
     Vehicles move a large number of people and cargo. Often two or more vehicles are physically coupled together to move freight or other cargo, people, and/or animals. 
     A ubiquitous example of coupled vehicles is that of the tractor-trailer or semi-trailer combination, which employs a tractor, sometimes referred to as a primary mover, coupled to pull one or more trailers. Such tractor-trailers or semis come in a large variety of forms and are typically used to move freight over relatively long distances. The tractor is the drive mechanism that pulls or pushes the trailer. The tractor includes the engine, typically an internal combustion diesel engine or an electric vehicle, a transmission and drive wheels. The tractor typically includes a cab where the driver or operator sits to operate the tractor. The tractor may also include a sleep cab which provides accommodations for the driver or operator when not in motion. The trailers are typically removably coupled to the tractor via a coupler such as a fifth wheel carried by the tractor and kingpin carried by the trailer, or less commonly via an automatic coupling. A semi-trailer typically does not have a front axle, relying on the tractor for support of a portion of the trailer&#39;s weight, and may have one or typically more rear axles. In some instances, a tractor may pull multiple trailers, forming a train. In such a case, the following trailer(s) may not have front axles and may rely on the proceeding trailers for supporting a portion of the trailer&#39;s weight. Trailers come in a large variety, for example box, bus, curtain side, flatbed, “low boy”, refrigerated or “reefer”, tanker, dry bulk, car carrier, drop deck, “double decker” or sidelifter. Trailers are often substantially rectangular, having a front end which is coupled to the tractor and a back end spaced remotely from the tractor. The back end often includes a door or more commonly a pair of doors to provide access to an interior of the trailer from an exterior thereof. The front end, back end, and sides of a trailer tend to be vertically extending surfaces. In some instances, a portion of a trailer or an accessory thereof may extend horizontally from these vertically extending surfaces, for example a refrigeration system or heater or nose cone may extend forward from the front of a trailer in to a gap region between a tractor and coupled trailer. 
     Another example of coupled vehicles is railroad trains. Railroad trains typically include one or more locomotives that pull a number of cars along a set of tracks. The cars may include passenger cars and/or freight cars. The freight cars can take a large variety of forms, similar in some respects to the various types of trailers. 
     Tractor-trailers or semis and railroad trains are increasingly used to move containerized cargo. This multi-modal approach allows containerized cargo to be conveniently moved between ships (e.g., ocean going container ships, barges), tractor trailers, and/or railroad trains. For instance, containers may arrive by ship from overseas. Tractor-trailers may move some of the containers over roads to warehouses or to retail locations. Tractor-trailers may move some of the containers to rail yards. Some containers may be moved via railroad trains, and subsequently moved to a desired location via tractor-trailers. 
     Coupled vehicles typically must be capable of operating in a variety of environments. For example, coupled vehicles must be capable of carrying loads at relatively high speed over long distance. For instance, tractor-trailer combinations typically must be able to haul freight over highways such as toll roads or freeways within some posted speed limit. Such highways are typically relatively straight over long distances, and do not require much turning or maneuvering. Such tractor-trailers typically must also be able to haul freight over surface streets at much lower posted speed limits. Travel over surface streets typically requires higher maneuverability than travel over highways, often requiring essentially right angle turns in relatively confined spaces or navigating steep elevational changes. 
     Fuel efficiency is typically an important concern when operating coupled vehicles. A large portion of the cost of moving freight or people is attributable to fuel costs and the majority of fuel at highway speeds is spent overcoming aerodynamic drag. Fuel efficiency tends to decrease as speed increases. Fuel efficiency while traveling on highways is particularly a concern since the average speed is higher than on surface roads and, for most operations, more time is spent on highways than on surface streets. 
     Numerous approaches have been suggested for increasing fuel efficiency of vehicles. These approaches typically employ ferrules, fairings, cowlings, air dams, deflectors, and/or spoilers located at various locations, for instance on a front of the tractor or over a roof of the tractor. Some approaches for increasing fuel efficiency specifically address the problem created by the fact that there is a gap between the tractor and trailer. Some of the approaches for increasing fuel efficiency are illustrated in (e.g.) U.S. Pat. Nos. 3,697,120; 3,711,146; 3,934,923; 4,036,519; 4,750,772; 5,078,448; and 6,585,312, referenced herein as useful background information. 
     SUMMARY OF THE INVENTION 
     One aspect of the disclosure provides a fairing system, comprising a fixed fairing assembly configured to attach to a cab of a tractor-trailer, the fixed fairing assembly being a unitary assembly and comprising a first lateral portion, a second lateral portion, and a movable top portion; a movable fairing assembly configured to attach to at least one of the fixed fairing assembly or the cab of the tractor-trailer; and an actuator assembly configured to move the movable fairing assembly relative to the fixed fairing assembly. 
     One aspect of the disclosure provides a fairing system, comprising: a fixed fairing assembly configured to attach to a cab of a tractor-trailer, the fixed fairing assembly being a unitary assembly and comprising a first lateral portion, a second lateral portion, and a movable top portion; a movable fairing assembly configured to attach to at least one of the fixed fairing assembly or the cab of the tractor-trailer; and an actuator assembly configured to move the movable fairing assembly relative to the fixed fairing assembly. 
     In one example, the fixed fairing assembly is configured to be at least one of: removably attached to the cab of the tractor-trailer; or permanently attached to the cab of the tractor-trailer. 
     In one example, the fixed fairing assembly and the movable fairing assembly are configured to substantially completely enclose a gap defined between the cab and a trailer of the tractor-trailer. 
     In one example, the movable fairing assembly is configured to be at least one of: removably attached to the cab of the tractor-trailer; permanently attached to the cab of the tractor-trailer; removably attached to the fixed fairing assembly; or permanently attached to the fixed fairing assembly. 
     In one example, the actuator assembly is configured to move the movable fairing assembly from a first undeployed position to a second deployed position. 
     In one example, the actuator assembly is configured to move the movable fairing assembly to at least one intermediate position between the first undeployed position and the second deployed position. 
     Another aspect of the disclosure provides a fairing system, comprising: a fixed fairing assembly configured to attach to a cab of a tractor-trailer; a movable fairing assembly configured to attach to at least one of the fixed fairing assembly or the cab of the tractor-trailer, the movable fairing assembly configured to move from a first undeployed position to a second deployed position in which the fixed fairing assembly and at least one lateral portion the movable fairing assembly forms a continuously outwardly tapered surface from a rear of the cab to the trailer; and an actuator assembly configured to move the movable fairing assembly relative to the fixed fairing assembly. 
     In one example, the at least one lateral portion comprises a plurality of lateral portions. 
     Another aspect of the disclosure provides a fairing system configured to attach to a cab of a tractor-trailer, the cab having a first rectangular cross-sectional profile and a trailer of the tractor-trailer having a second, larger, rectangular cross-sectional profile, the fairing system comprising: a fixed fairing assembly configured to attach to a cab of a tractor-trailer; a movable fairing assembly configured to attach to at least one of the fixed fairing assembly or the cab of the tractor-trailer, the movable fairing assembly configured to move from a first undeployed position to a second deployed position in which the fixed fairing assembly and the movable fairing assembly form a continuously tapered surface from the first rectangular cross-sectional profile to the second, larger, rectangular cross-sectional profile; and an actuator assembly configured to move the movable fairing assembly relative to the fixed fairing assembly. 
     Another aspect of the disclosure provides a fairing system, comprising: a fixed fairing assembly configured to attach to a cab of a tractor-trailer, the fixed fairing assembly having a movable first top portion; a movable fairing assembly configured to attach to at least one of the fixed fairing assembly or the cab of the tractor-trailer, the movable fairing assembly having a movable second top portion, the movable fairing assembly configured to move from a first undeployed position to a second deployed position during which the movable first top portion rotates in synchronicity with the movable second top portion; and an actuator assembly configured to move the movable fairing assembly relative to the fixed fairing assembly. 
     Another aspect of the disclosure provides a fairing system, comprising: a fixed fairing assembly configured to attach to a cab of a tractor-trailer, the fixed fairing assembly having a movable first top portion; a movable fairing assembly configured to attach to at least one of the fixed fairing assembly or the cab of the tractor-trailer, the movable fairing assembly having a movable second top portion, the movable fairing assembly configured to move from a first undeployed position to a second deployed position during which the movable first top portion rotates rearward and downward; and an actuator assembly configured to move the movable fairing assembly relative to the fixed fairing assembly. 
     Another aspect of the disclosure provides a fairing system, comprising: a fixed fairing assembly configured to attach to a cab of a tractor-trailer, the fixed fairing assembly having a movable first top portion; a movable fairing assembly configured to attach to at least one of the fixed fairing assembly or the cab of the tractor-trailer, the movable cab fairing assembly having a movable second top portion, the movable fairing assembly configured to move from a first undeployed position to a second deployed position during which the movable second top portion rotates rearward and moves upward; and an actuator assembly configured to move the movable fairing assembly relative to the fixed fairing assembly. 
     Another aspect of the disclosure provides a fairing system, comprising: a fixed fairing assembly configured to attach to a cab of a tractor-trailer, the fixed cab fairing assembly having a movable first top portion; a movable fairing assembly configured to removably attached to at least one of the fixed cab fairing assembly or the cab of the tractor-trailer, the movable cab fairing assembly having a movable second top portion, the movable fairing assembly configured to move from a first undeployed position to a second deployed position during which the movable first top portion rotates rearward and moves downward and the movable second top portion rotates rearward and moves upward in synchronicity with the movement of the movable first top portion; an actuator assembly configured to move the movable fairing assembly relative to the fixed fairing assembly. 
     Another aspect of the disclosure provides a fairing system, comprising: a fixed fairing assembly configured to attach to a cab of a tractor-trailer, the fixed fairing assembly having a movable first top portion; a movable fairing assembly configured to attach to at least one of the fixed fairing assembly or the cab of the tractor-trailer, the movable fairing assembly having a movable second top portion, the movable fairing assembly configured to move from a first undeployed position to a second deployed position during which the movable second top portion rotates rearward and upward to at least partially cover a gap defined between the cab and a trailer; an actuator assembly configured to move the movable fairing assembly relative to the fixed fairing assembly. 
     Another aspect of the disclosure provides a fairing system, comprising: a fixed fairing assembly configured to attach to a cab of a tractor-trailer, the fixed fairing assembly having a movable first top portion; a movable fairing assembly configured to attach to at least one of the fixed fairing assembly or the cab of the tractor-trailer, the movable fairing assembly having a movable second top portion, the movable fairing assembly configured to move from a first undeployed position to a second deployed position during which the movable first top portion rotates rearward and downward and the movable second top portion rotates rearward and moves upward to form a substantially continuous surface between the cab and a trailer; an actuator assembly configured to move the movable fairing assembly relative to the fixed fairing assembly. 
     In one example, the substantially continuous surface is configured to prevent a passage of air flow from outside of a gap defined between the cab and a trailer into the gap via the substantially continuous surface. 
     Another aspect of the disclosure provides a fairing system, comprising: a fixed fairing assembly configured to attach to a cab of a tractor-trailer, the fixed fairing assembly having a first plurality of lateral portions; a movable fairing assembly configured to attach to at least one of the fixed fairing assembly or the cab of the tractor-trailer, the movable fairing assembly having a second plurality of lateral portions, the movable fairing assembly configured to move from a first undeployed position to a second deployed position during which at least one of the second plurality of lateral portions rotate outward and upward; an actuator assembly configured to move the movable fairing assembly relative to the fixed fairing assembly 
     Another aspect of the disclosure provides a fairing system, comprising: a fixed fairing assembly configured to attach to a cab of a tractor-trailer, the fixed cab fairing assembly having a first plurality of lateral portions; a movable fairing assembly configured to attach to at least one of the fixed fairing assembly or the cab of the tractor-trailer, the movable cab fairing assembly having a second plurality of lateral portions, the movable fairing assembly configured to move from a first undeployed position to a second deployed position thereby defining a longitudinal gap between the first plurality of lateral portions and the second plurality of lateral portions; an actuator assembly configured to move the movable fairing assembly relative to the fixed fairing assembly. 
     In one example, the longitudinal gap has a length such that air flow from outside of a gap defined between the cab and a trailer is preventing from passing into the gap via the longitudinal gap. 
     Another aspect of the disclosure provides a method of operating a tractor-trailer, comprising: attaching a fixed fairing assembly to a cab of the tractor-trailer; attaching a movable fairing assembly to at least one of the fixed fairing assembly or the cab; modifying a direction of movement of the tractor-trailer; and in response to the modified direction of movement, rotating a movable first top portion of the fixed fairing assembly and rotating a movable second top portion of the movable fairing assembly to accommodate for pivotal rotation of the trailer relative to the cab. 
     In one example, the method further comprises deploying the movable fairing assembly from a first undeployed position to a second deployed position. 
     In one example, the method further comprises modifying a direction of movement of the tractor-trailer comprises at least one of: a driver turning a wheel; or turning a wheel in response to a command from a controller. 
     Another aspect of the disclosure provides a fairing system, comprising: a fixed fairing assembly configured to attach to a cab of a tractor-trailer; a movable fairing assembly configured to attach to at least one of the fixed fairing assembly or the cab of the tractor-trailer; a wind sensor configured to detect at least one of a wind speed or a wind direction; an actuator assembly configured to move the movable fairing assembly relative to the fixed fairing assembly based in part on at least one of the detected wind speed or the detected wind direction. 
     Another aspect of the disclosure provides a fairing system, comprising: a fixed fairing assembly configured to attach to a cab of a tractor-trailer and forming a substantially continuous surface with at least one surface of the cab; a movable fairing assembly configured to attach to at least one of the fixed fairing assembly or the cab of the tractor-trailer; and an actuator assembly configured to move the movable fairing assembly relative to the fixed fairing assembly. 
     In one example, the substantially continuous surface is configured to prevent a passage of air flow from outside of a gap defined between the cab and a trailer into the gap via the substantially continuous surface. 
     Another aspect of the disclosure provides a fairing system, comprising: a fixed fairing assembly configured to attach to a cab of a tractor-trailer; a movable fairing assembly configured to attach to at least one of the fixed fairing assembly or the cab of the tractor-trailer; an actuator assembly configured to move the movable fairing assembly relative to the fixed fairing assembly, the actuator comprising an airbag assembly. 
     Another aspect of the disclosure provides a tractor-trailer system, comprising: an engine management system configured to receive at least one parameter from an engine of a tractor trailer; a fairing system having at least one actuator, the actuator configured to selectively move a movable fairing assembly; and a controller in communication with the engine management system and configured to issue a command to cause selective movement of the movable fairing assembly based at least in part on the at least one parameter. 
     In one example, the selective movement comprises at least one of: direction of movement of the movable fairing assembly, speed of movement of the movable fairing assembly, or distance of movement of the movable fairing assembly. 
     In one example, the at least one parameter comprises at least one of: speed, temperature, gear, power, throttle position, fuel consumption, fuel rate, brake pressure, or brake position. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention description below refers to the accompanying drawings, of which: 
         FIG.  1 A  is side view of a tractor-trailer with a fairing system in the retracted configuration; 
         FIG.  1 B  is a side view of the tractor-trailer with the fairing system in the deployed configuration; 
         FIG.  2 A  is a rear perspective view of a cab of the tractor-trailer with a fairing system in a deployed state; 
         FIG.  2 B  is a rear perspective view of a cab of the tractor-trailer with a fairing system in a retracted state; 
         FIG.  2 C  is a rear perspective view of a fairing assembly in a deployed state; 
         FIG.  2 D  is a front perspective view of a fairing assembly in a deployed state; 
         FIG.  3 A  is a side view of a tractor-trailer with a fairing system in a retracted state; 
         FIG.  3 B  is a side view of a tractor-trailer with a fairing system in a deployed state; 
         FIG.  4 A  is a top view of a tractor-trailer with a fairing system in a retracted state; 
         FIG.  4 B  is a top view of a tractor-trailer with a fairing system in a deployed state; 
         FIG.  5 A  is a top view of a tractor-trailer with an articulated trailer relative to the cab with a fairing system in a retracted state; 
         FIG.  5 B  is a rear perspective view of a tractor-trailer with an articulated trailer relative to the cab with a fairing system in a retracted state; 
         FIG.  6 A  is a rear perspective view of a tractor-trailer and reefer unit with a fairing system in a retracted state; 
         FIG.  6 B  is a rear perspective view of a tractor-trailer and reefer unit with a fairing system in a deployed state; 
         FIG.  7 A  is a top view of a tractor-trailer and reefer unit with a fairing system in a retracted state; 
         FIG.  7 B  is a top view of a tractor-trailer and reefer unit with a fairing system in a deployed state; 
         FIG.  8 A  is a front perspective view of a tractor-trailer with a fairing system in a deployed state; 
         FIG.  8 B  is a rear perspective view of a tractor-trailer with an articulated trailer relative to the cab with a fairing system in a deployed state; 
         FIG.  9 A  is a front perspective view of a tractor-trailer with a fairing system in a deployed state; 
         FIG.  9 B  is a rear perspective view of a tractor-trailer with an articulated trailer relative to the cab with a fairing system in a deployed state; 
         FIG.  10 A  is a front perspective view of a tractor-trailer with a fairing system in a deployed state; 
         FIG.  10 B  is a rear perspective view of a tractor-trailer with an articulated trailer relative to the cab with a fairing system in a deployed state; 
         FIG.  11    is a side view of a tractor-trailer cab with a fairing system in a hyperextended deployed state; and 
         FIG.  12    is a computer system for controlling a fairing system according to one or more aspects of the disclosure. 
     
    
    
     DETAILED DESCRIPTION 
       FIG.  1 A  is side view of a tractor-trailer with a fairing system in the retracted state and  FIG.  1 B  is a side view of the tractor-trailer with the fairing system in the deployed state. 
     The hitches/assembled tractor-trailer  100  can include a tractor  110  and a trailer  120 . The tractor  110 , e.g., a lead vehicle, which in typical operation is at the front or ahead of a trailer  120 , e.g., trailing vehicle, with respect to a direction of travel during normal operation. It is recognized that in some instances, the lead vehicle may at times be behind the trailing vehicle, for example when backing up. In the illustrated implementation, the lead vehicle is the tractor  110 , which includes an engine (e.g., internal combustion diesel engine, not shown), a transmission (not shown), drive wheels, steering wheel, throttle (not shown), and brakes (not shown). In other examples, the tractor-trailer  100  can be an electric vehicle. The tractor  110  may be typical of those commonly used in long haul trucking within the United States, such as those manufactured and sold under the Kenworth® and Peterbilt® trademarks, among other brands/manufacturers. The tractor  110  may include a cab  110   a  in which the driver or operator sits while driving or operating the tractor  110 . The tractor  110  may also include a sleeper cab  110   d , located behind the cab  110   c , which a driver or operator may use as a residence or sleep area when the tractor  110  is parked. The back of the tractor  110  may have a width. The tractor  110  may have one or more ferrules, fairings, cowlings, air dams, deflectors, and/or spoilers located at various locations to reduce aerodynamic drag and thereby increase fuel efficiency. 
     The trailer  120  may take any of a variety of forms. For example, the trailer  120  may take the form of a semi-trailer, which includes a set of rear wheels, relying on the tractor  110  to support a portion of the weight of the trailer  120  at a front end of the trailer  120 , instead of having a front axle. The trailer  120  may take the form of a box trailer, or any variety of other types of trailers, for instance bus, curtain side, flatbed, “low boy”, refrigerated or “reefer”, tanker, dry bulk, car carrier, drop deck, “double decker” or sidelifter trailers. As illustrated the trailer typically has a front that extends substantially vertically, although one or more portions or objects may extend horizontally forward of from the front of the trailer, e.g., a cooler unit, a heater unit, a nose cone. 
     Although the trailer  120  is depicted as having a same or similar height with respect to the tractor  110 , in some examples the trailer  120  can have a height that is different than the tractor  110 . In particular, in an example, the trailer  120  can have a height that is greater than the tractor  110 . 
     As shown, the trailer  120  is physically coupled to the tractor  110 . Tractors  110  typically carry a fifth wheel, to which the trailer  120  is removably or detachably physically coupled. Fifth wheels generally include metal plates skid plates and jaws on one vehicle, usually the tractor, and which receive a kingpin carried by the other vehicle, usually the trailer. Fifth wheels are commonly employed in tractor trailer(s)  10 , so will not be described in detail. There may be additional couplings between the tractor  110  or components thereof and the trailer  120  or components thereof. For example, there may be one or more electrical couplings, pneumatic couplings and/or hydraulic couplings. Such may, for example, provide electrical power or signals to the trailer  120  or component thereof, for instance a refrigeration system, turn signal indicators and/or brake lights. Such may, for example, supply pressurized fluid or air to the trailer  120  or a component thereof, for instance brakes. 
     While  FIGS.  1 A-B  depict a tractor-trailer  100 , it is contemplated that the fairing system  140  can be implemented in a variety of vehicle types, such as trains, pick-up trucks, or any type of vehicle capable of or configured for pulling or towing a trailer. 
     As shown in  FIG.  1 A , a gap  130  is defined between the tractor  110  and the trailer  120 . The gap region  130  is sufficiently large as to allow the tractor-trailer  100  to maneuver as need, for example through surface streets of a city of town. For instance, the gap  130  may be approximately 1.5 meters or 4.5 feet in length. This gap region  130  negatively affects the aerodynamics associated with the vehicle body, and hence hinders fuel efficiency, particularly at higher speeds such as highway speeds (e.g., 55-75 mph). 
     The gap  130  is a three-dimensional volume defined at least in part by: a rear surface of the tractor  110  (e.g., a rear surface of cab  110   a  or sleeper cab  110   d ) and imaginary planes connecting the rectangular profiles between the tractor  110  and the trailer  120 . 
     As shown in  FIG.  1 B , the fairing system  140  is in a deployed configuration and at least partially, substantially completely, or completely covers the gap  130 . Substantially completely, for example, can include configurations whereby the fairing system  140  does not completely cover the gap  130 , but the coverage afforded in this example is sufficient to prevent appreciable airflow into/out of the gap  130  in a manner that substantially improves aerodynamics and fuel efficiency. 
     In an example, the fairing system  140 , in the deployed configuration, completely encloses the tractor-trailer gap  130 . Enclosing (at least partially, substantially completely, or completely) the gap  130  keeps airflow close to an outer surface of the fairing system  140  (e.g., outer surfaces of portions  145   a - c  and/or  150   a - c  described below) so that the airflow moves from tractor  110  to trailer  120  without the airflow impacting trailer edges, and maintaining maximum “seal” or isolation of the volume that they enclose which is of higher pressure than the outside airflow. Additionally, to maximize this effect, outward taper blending from cab to trailer (as shown below in  FIGS.  3 A-B  and  4 A-B) increases the benefits of this pressure differential by providing additional thrust on the fairings themselves at no cost to drag. The exemplary implementation of the fairing system  140  herein is arranged to enclose (completely, substantially completely, or partially) the tractor-trailer gap  130  in an active manner, extending or deploying to fill the gap  130  at highway speeds and retracting or undeploying to allow trailer articulation at low speeds. Advantageously, the fairing system  140  imposes the fewest constraints on cab and trailer mounted equipment, tractor-trailer operation, and maximizes potential integration with the tractor  110  and cab  110   a.    
     The fairing system  140  of the present application is advantageously compatible with reefers (as described below relative to  FIGS.  6 A-B  and  7 A-B), heaters, and other trailer-mounted equipment. Further, it is compatible with spares tires, stock hook-up lights, hose hangers, and other cab-mounted equipment. 
       FIG.  2 A  is a rear perspective view of a cab  110   a  of the tractor-trailer  100  with a fairing system  140  in a deployed state and  FIG.  2 B  is a rear perspective view of a cab  110   a  of the tractor-trailer  100  with a fairing system  140  in a retracted state. The fairing system  140  can include a fixed fairing assembly  145  and a movable fairing assembly  150 . Additionally,  FIG.  2 C  is a rear perspective view of a fairing assembly in a deployed state and  FIG.  2 D  is a front perspective view of a fairing assembly in a deployed state. 
     The fixed fairing assembly  145  can include a first lateral portion  145   a , a second lateral portion  145   b , and a top portion  145   c . In an example, the portions  145   a - c  can be unitary while in other examples, the portions  145   a - c  can separate subassemblies or the pieces interconnected to form overall fixed fairing assembly  145 . 
     The movable fairing assembly  150  can include a first lateral portion  150   a , a second lateral portion  150   b , and a top portion  150   c . In an example, the portions  150   a - c  can be unitary while in other examples, the portions  150   a - c  can be separate subassemblies or pieces interconnected to form the overall movable fairing assembly  150 . Advantageously, the fairing system  140  and assemblies  145 ,  150  of the present application is/are highly contoured/curved to match optimal airflow of the tractor and/or trailer, e.g., tractor-trailer in combination. 
     The fixed fairing assembly  145  or the movable fairing assembly  150  can be constructed any type of material, such as injection molded plastic, thermoformed plastic, fiberglass reinforced plastic or composite, metal framework, or a combination thereof. The assemblies  145  or  150  can also include integral cab mounting features and may be designed to be compliant to impacts and allow deformation, while maintaining sufficient rigidity for aerodynamic purposes. This could be zonal or in its entirety. The fixed fairing assembly  145  may include additional integration features including hand holds, access holes, and aerodynamic vents. 
     The fairing system  140 , or any component thereof (including assemblies  145 ,  150 ), can be directly, indirectly, permanently, semi-permanently, and/or removably attached or coupled to the cab  110   a  of the tractor  110  (or any other portion of the trailer  110 , such as sleeper cab  110   d ). For example, the fixed fairing assembly  145  can be coupled directly to the cab  110   a  of the tractor  110  by integral attachment points on a rear of the cab  110   a  of the tractor  110  or by drilled attachment points on a rear of the cab  110   a  of the tractor  110 . The movable fairing assembly  150  can be removably (or permanently) coupled directly or indirectly to the fixed fairing assembly  145  and/or removably (or permanently) coupled directly or indirectly to the cab  110   a  of the tractor  110 . When coupled to the cab  110   a  of the tractor  110 , the movable fairing assembly  150  can be coupled to the same or additional integral attachment points or the same or different drilled attachment points described above. 
     The fairing system  140  can include one or more mounting structures  155  coupled to the cab  110   a  of the tractor  110  and that can be coupled to the movable fairing assembly  150  via one or more swing arms  160 . Motion of the swing arms  160  (as caused by an actuator assembly described below) can provide for a corresponding motion of the movable fairing assembly  150 , as will be described in greater detail below. The mounting structure  155  can be coupled to the cab  110   a  of the tractor  110  via the same or additional integral attachment points or the same or different drilled attachment points described above. 
     During deployment, the lateral portions  150   a ,  150   b  are arranged to move upward and outward by virtue of the motion of the swing arms  160 , as shown in  FIGS.  3 A-B  and  4 A-B, as they move rearward covering the gap  130  in a semi-telescopic fashion with respect to the fixed fairing assembly  145 . The outward and upward movement of the lateral portions  150   a ,  150   b  achieves an outward taper from the trailing edge profile of the fixed fairing assembly  145  (e.g., one or more of portions  145   a, b, c ) to the trailer  120 . This motion is achieved through the use of the one or more swing arms  160  attached to the fixed fairing assembly  145  or cab  110   a  of the tractor  110 . In an example, each swing arm  160  is connected respectively to the movable fairing assembly  150  and the cab  110   a  (and/or mounting structure  155 ) via a revolute joint  160   a  at each end. In another example, spherical joints could be employed. In the example of spherical joints, a central translating joint can be implemented to accommodate more load to adequately constrain the extra degrees of freedom. 
     The geometry of the one or more swing arms  160  is highly variable depending on particular implementations and by the desired end position of the movable fairing assembly  150 . In an example, the one or more swing arms  160  can be optimized for variable translation. The swing arms  160  are oriented such that they swing outward as they rotate facilitating the outward movement. The rotation points of the swing arms  160  facilitate the back and upward movement of the lateral portions  150   a, b . In this way, the swing arms  160  rotate through imaginary planes that are not parallel to one another and converge at a point within or in front of the cab  110   a  of the tractor  110 . This arrangement allows the lateral portions  150   a, b  to rotate outward during deployment. The length and orientation of the swing arms  160  is such that the translation rearward is greater than the translation upward. 
     An actuator assembly  170  (not shown in  FIGS.  2 C- 2 D ) including one or more actuators can be implemented to initiate motion of the swing arms  160  and ultimately the movable fairing assembly  150 . The actuator assembly  170  can be positioned below a lower swing arm  160  and between the lower swing arm  160  and cab  110 . While one actuator  170  is depicted in  FIG.  2 A , additional actuators  170  can be implemented with respect to one or more of the remaining swing arms  160 . For example, actuators  170  can be implemented on the lower swing arms  160  only, one actuator on a lower swing arm and one on an upper swing arm  160   160 , or any other configuration. The kinematics of the swing arms  160  allow use of high load, short displacement actuators such as air bags (as shown in  FIGS.  2 A-B ) with end fittings and a collapsible rubber bladder. In the example of air bags, an inflated airbag can hold the swing arms  160  and ultimately the movable fairing assembly  150  in the deployed position, while deflation of the airbag can cause retraction/undeployment and gravity can return the movable fairing assembly  150  back to the undeployed position from the deployed position. In other example, pneumatic, hydraulic cylinders, electro-mechanical actuators, or pressure/force elements may be used. 
       FIG.  3 A  is a side view of a tractor-trailer with a fairing system in a retracted state and  FIG.  3 B  is a side view of a tractor-trailer with a fairing system in a deployed state. 
     The top portion  145   c  can be movable or rotatable relative to the lateral portions  145   a, b  to enable trailer corner clearance during turning/articulation of the tractor-trailer  120  where the corner of the trailer  120  swings through the central portion (as shown in  FIGS.  5 A-B ). The motion envelope of the trailer and trailer corner is maximum when the cab  110   a  or trailer  120  is pitch up relative to the other causing the upper corner of the trailer to be the closest to the tractor/cab. The top portion  145   c  is movable or rotatable relative to the lateral portions  145   a ,  145   b  via a hinge  147 . In another example, the top portion  145   c  may be a raised central portion (also referred to as a “bubble”) that is fixed relative to lateral portions  145   a, b  to facilitate trailer  120  clearance. This example is described below relative to  FIGS.  9 - 10   . 
     The top portion  150   c  can be movable or rotatable relative to the lateral portions  150   a, b . The top portion  150   c  is movable or rotatable relative to the lateral portions  150   a, b  via a hinge  152 . When moving from the retracted state of  FIG.  3 A  to the deployed state of  FIG.  3 B , the movable top portion  150   c  rotates rearward and moves upward (by virtue of the movement of swing arms  160 ) synchronously with rearward rotation and downward movement of the top portion  145   c  of the movable fairing assembly to cover, partially cover, of substantially completely cover/enclose the central portion of the tractor-trailer gap  140  when the device is extended/deployed at speed, providing a continuous or semi-continuous top surface. In this regard, the top portion  145   c  rotates rearward and moves downward in synchronicity with the rearward rotation and upward movement of the top portion  150   c . Synchronous can refer to movement of the top portion  150   c  and movement of the top portion  145   c  can, at least partially, overlap in time. The movable top portion  150   c  could be biased in rotation upward (beyond horizontal) to better facilitate trailer  120  clearance during turning, or could offer compliance and be pushed out of the way during articulation. 
     In another example, either or both of the top portions  145   c  or  150   c  can be manufactured from a compliant material to enable trailer interference without damage, while still holding its shape for aerodynamic functional purposes. 
     Advantageously, the top portions  145   c  and  150   c  combine to at least partially, substantially completely, or completely, cover or enclose a top portion of the gap  130 , maximizing trailer envelope and gap coverage. This coverage also occurs where a rectangular profile of the cab  110  is different than a rectangular profile of the trailer  120 . In this way, the top portions  145   c  and  150   c  have an upward taper to account for the trailer profile being larger than the cab profile (in addition to the continuously tapered surfaces of respective lateral portions  145   a,b  and  150   a,b ). In an example, the top portions  145   c  and  150   c  can combined to form a continuous or substantially continuous surface between cab  110  and trailer  120  and can be a continuous or substantially continuous tapered surface. The taper is depicted generally in  FIG.  3 B , in which the taper is directed upward relative to a longitudinal axis of the tractor trailer  100 . The taper can be achieved in examples where the trailer  120  has a height that is equal to or greater than a height of the cab  110   a  of trailer  110 . 
       FIG.  4 A  is a top view of a tractor-trailer with a fairing system in a retracted state and  FIG.  4 B  is a top view of a tractor-trailer with a fairing system in a deployed state. 
     The lateral portions  145   a ,  145   b  or  150   a ,  150   b  may include aerodynamic surfaces that are primarily vertical and fill in the sides of the tractor-trailer gap, but extend around and transition into horizontal surfaces at the top portion  145   c  and top portion  150   c  respectively such that they partially cover the top of the tractor-trailer gap  130 . The lateral portions  150   a ,  150   b  can be connected to each other with a translating joint (e.g., hinge  152 ) that positions a top portion  150   c  relative to the lateral portions  150   a ,  150   b . The top portion  150   c  moves rearward and upwardly with the lateral portions  150   a ,  150   b  while rotating downward synchronously at the trailing edge with the top portion  145   c  of the fixed fairing assembly  145 . In an example, the movable top portion  150   c  and/or the top portion  145   c  is arranged so as to be biased in rotation upward to better facilitate trailer clearance during turning when the movable fairing assembly  150  is retracted. 
     In another example, the top portion  150   c  of the movable fairing assembly  150  can include a raised central portion or “bubble” to facilitate trailer clearance. In this example, the top portion  150   c  (e.g., the “bubble” portion) would translate rearward with the lateral portions  150   a    150   b , but would not rotate upward. This example is further described below with respect to  FIG.  10   . 
     Additionally, the top portion  150   c  can be manufactured from a compliant material to enable trailer interference without damage, while still holding its shape for aerodynamic functional purposes. 
     The shape of the portions  150   a ,  150   b ,  150   c  that make up the movable fairing assembly  150  can be optimized to work with the airflow coming off of the fixed fairing assembly  145  and may partially overlap or not overlap at all with the fixed fairing assembly  145  depending on the gap to be filled, the tuned aerodynamic performance of the total system, and the speed of the tractor. 
     The lateral portions  145   a ,  150   b  and  150   a ,  150   b , as shown in  FIG.  4 B , combine to form a continuously (or substantially continuously) outwardly tapered surface from cab  110   a  of tractor  110  to trailer  120 . In an example, the portions  145   a ,  150   b  and  150   a ,  150   b  can combine to form a substantially continuously outwardly tapered surface, which includes configurations whereby the surfaces includes one or more discontinuities, but the coverage is sufficient to prevent appreciable airflow into/out of the gap  130  in a manner that substantially improves aerodynamics and fuel efficiency. 
     As also shown, the top portions  145   c  and  150   c  at least partially, substantially completely, or completely cover or enclose a top dimension of the gap  130 . The combination of portions  145   a - c  and  150   a - c  provide for at least partial, complete, or substantially complete coverage of the gap  130  relative to side and top dimensions thereof. 
       FIG.  5 A  is a top view of a tractor-trailer  100  and reefer  165  with an articulated trailer  120  relative to the cab  110   a  of the tractor  110  with a fairing system  140  in a deployed state and  FIG.  5 B  is a rear perspective view of a tractor-trailer and reefer  165  with an articulated trailer relative to the cab with a fairing system in a deployed state. 
     As depicted, the trailer  120  includes a reefer  165 . During a turn or other driving maneuver, the trailer  120  can articulate relative to the cab  110 . In this manner, the corner  165   a  of the reefer is closest to the cab  110  when the trailer is articulated at approximately 45 degrees. As shown in  FIG.  5 B , the reefer  165  and the trailer  120  clear the fairing system  140  (including fixed and movable fairing assemblies  145  and  150 ). Clearance is achieved in any of the examples of fairing assembly described herein, including any combination of top portion  145   c  being movable or fixed relative to lateral portions  145   a ,  150   b  and/or top portion  150   c  being movable or fixed relative to lateral portions  150   a ,  150   b . In an example where the top portion  145   c  and the top portion  150   c  are both movable, a corner  165   a , other portion of the reefer  165 , or the trailer  120  can make contact with the top portion  150   c , causing an upward movement of the top portion  150   c  and top portion  145   c  and providing clearance. 
       FIG.  6 A  is a rear perspective view of a tractor-trailer and reefer unit with a fairing system in a retracted state and  FIG.  6 B  is a rear perspective view of a tractor-trailer and reefer unit with a fairing system in a deployed state.  FIG.  7 A  is a top view of a tractor-trailer and reefer unit with a fairing system in a retracted state and  FIG.  7 B  is a top view of a tractor-trailer and reefer unit with a fairing system in a deployed state. 
     In the retracted state of  FIGS.  6 A and  7 A , the reefer  165  is positioned within the gap  130 , or at least partially defines the gap. As the fairing system  110  moves from the retracted state to the deployed state of  FIGS.  6 B and  7 B , the gap  130  is partially, substantially completely, or completely covered by the fairing system  140 , including fixed and movable fairing assemblies  145  and  150 . 
       FIG.  8 A  is a front perspective view of a tractor-trailer with a fairing system  840  in a deployed state and  FIG.  8 B  is a rear perspective view of a tractor-trailer with an articulated trailer relative to the cab with a fairing system in a deployed state. 
     In this example, each of the top portions  845   c  and  850   c  are both movable. That is to say, the top portion  845   c  is movable or rotatable relative to lateral portions  845   a, b  and the top portion  850   c  is movable or rotatable relative to lateral portions  850   a, b . In this way, where the trailer articulates as shown in  FIG.  8 B , a corner  120   a  of the trailer  120  can contact the top portion  850   c  and impart an upward and horizontal force thereon. This force causes the top portion  850   c  to move upward and frontward, and subsequently contact and cause the top portion  845   c  to synchronously move to provide clearance for the corner  820   a  and trailer  820 . In an example, the top portions  145   c  and  150   c  can move synchronously. In some examples, the top portions  145   c  and  150   c  can be biased upward while the fairing assembly  840  is retracted to provide clearance. 
       FIG.  9 A  is a front perspective view of a tractor-trailer with a fairing system in a deployed state and  FIG.  9 B  is a rear perspective view of a tractor-trailer with an articulated trailer relative to the cab with a fairing system in a deployed state. 
     In this example, the top portion  945   c  is fixed (stationary) relative to the lateral portions  945   a ,  945   b  and the top portion  950   c  is movable relative to the lateral portions  950   a, b . In this way, where the trailer articulates as shown in  FIG.  9 B , a corner  120   a  of the trailer  120  can contact the top portion  950   c  and impart an upward and horizontal force thereon. This force causes the top portion  950   c  to move upward and frontward into a motion envelope defined by the top portion  945   c  to provide clearance for the corner  120   a  and trailer  120 . 
       FIG.  10 A  is a front perspective view of a tractor-trailer with a fairing system  1040  in a deployed state and  FIG.  10 B  is a rear perspective view of a tractor-trailer with an articulated trailer relative to the cab with a fairing system in a deployed state. 
     In this example, the top portion  1045   c  is fixed (stationary) relative to the lateral portions  1045   a, b  and the top portion  1050   c  is fixed (stationary) relative to the lateral portions  1050   a, b . In this way, where the trailer articulates as shown in  FIG.  10 B , a corner  120   a  of the trailer  120  moves into a motion envelope defined by the top portion  150   c . The top portion  1050   c  is within a motion envelope defined by top portion  1045   c  and provides clearance for the corner  120   a  and trailer  120 . 
       FIG.  11    is a side view of a tractor-trailer (trailer not shown) cab with a fairing system  1140  in a hyperextended deployed state. In this example, the movable fairing assembly  1150  (including lateral portion  1150   a  and top portion  1150   c ) can move to a position where the gap  130  is substantially covered by the combination of movable fairing assembly  1150  and fixed fairing assembly  1145  (including lateral portion  1145   a  and top portion  1145   c ), defining a gap  1190  between the assemblies  1145  and  1150 . In this regard, the hyperextended deployed state can cover a gap having a greater longitudinal length, but can provide substantial aerodynamic and fuel efficiency benefits. In one particular example, the assemblies  1145  and  1150  combine to substantially completely cover the gap  130 , defining gap  1190 , whereby the coverage is sufficient to prevent appreciable airflow into/out of the gap  130  in a manner that substantially improves aerodynamics and fuel efficiency. 
       FIG.  12    shows a control subsystem  2100  for a fairing system according to an illustrated embodiment. 
     The control subsystem  2100  is configured to automatically selectively move a movable fairing assembly  150  between a fully un-deployed or fully unextended configuration and a fully deployed or fully extended configuration, and optionally one or more partially deployed or intermediate configurations based on one or more conditions (e.g., speed of vehicle, location of vehicle, presence or absence of any obstacles in path of deployment, wind speed and/or wind direction, and/or temperature in an ambient environment. 
     The control subsystem  2100  can include a controller  2102 . The controller  2102  may include one or more hardware or circuitry-based processors (e.g., microprocessor, digital signal processor, programmable gate array, application specific integrated circuit, microcontroller)  2104 . The controller  2102  may include one or more processor-readable media for example memories or other storage mediums. For example, the controller  2102  may include read only memory  2106  and/or random access memory  2108 . The memories  2106 ,  2108  may store processor executable instructions that cause the processor  2104  to assess speed, location, or one or more thresholds, and to control a configuration or position of the movable fairing  150  in response thereto. 
     The controller  2102  may include one or more busses  2110  coupling the processor  2104  and memories  2106 ,  2108 . For example, the controller  2102  may include a power bus, instruction bus, data bus, address bus, etc. The busses can also provide signal paths to communicate with other devices or elements of the control subsystem  2100 . The control subsystem  2100  may also include one or more digital-to-analog (D/A) converters  2110  to convert digital signals from the processor  2104  into an analog form suitable to drive certain components. The control subsystem  2100  may also include one or more analog-to-digital (A/D) converters  2112  to convert analog signals from certain components into a digital form suitable for processing by the processor  2104 . 
     The control subsystem  2100  may include one or more actuators  2114  operable to move the movable fairing  150  between the fully un-deployed or fully retracted or fully unextended configuration and the fully extend or a fully deployed configuration, and optionally into any one or more of a number of partially deployed or partially extended configurations between the fully un-deployed and fully deployed configurations. As previously explained, the actuator(s)  2114  may, for example, take the form of a piston/cylinder pair  2114   a , a solenoid  2114   c , and/or an electric motor (e.g., stepper motor)  2114   c , or the airbag depicted in  FIGS.  2 A-B . In addition, at least one valve  2126  may be attached to or incorporated into the actuator  2114 , e.g., a piston cylinder  2114   a . The valve  2126  may be a mechanical control valve, a solenoid, or other like device that can selectively vent the actuator  2114  or provide a fluid (e.g., air, hydraulic fluid) under an elevated pressure. In the event of an error or a loss of power, the valve  2126  can be biased in the event of a power loss to deactivate the actuator  2114  such as, for example, by venting the air within a pneumatic actuator or hydraulic fluid. In this situation, the components of the movable fairing assembly  150  default to returning to the fully retracted or fully unextended configuration as a result of the components of the movable fairing assembly  150  applying a downward force to the deactivated actuator  2114 . In some implementations, the control subsystem  2100  may control the actuator  2114 , such as through controlling a fluid supply, to cause the actuator  2114  to retract the lateral portion  150   a  to elastically deform the lateral portion  150   a  without causing plastic deformation to the lateral portion  150   a  or the top portion  150   c . In some implementations, the control subsystem  2100  may control the actuator  2114 , such as through controlling a fluid supply, to cause the actuator  2114  to retract the lateral portion  150   b  to elastically deform the lateral portion  150   b  without causing plastic deformation to the lateral portion  150   b  or the top portion  150   c.    
     The valve  2126  can be arranged so that when it is biased it deactivates the actuator  2114  in various conditions, resulting in the components of the movable fairing assembly  150  automatically returning to the fully retracted or fully unextended configuration. Such conditions may arise, for example, in the event of a power loss to the tractor-trailer  100  or to the fairing system  140 , or in the event that the fairing system  140  is unable to communicate with the rest of the control subsystem  2100 , including the processor  2104 . In addition, such conditions may arise when one or more gauges or sensors indicate a potentially unsafe operating condition. Additionally or alternatively, some conditions may indicate that it may be efficient or desirable to transition the movable fairing  150  into a partially deployed or partially extended (e.g., intermediate) configuration, for example as explained elsewhere herein. 
     The control subsystem  2100  may include one or more speed sensors  2116 , which provide signals indicative or representative of a speed of the vehicle to the processor(s)  2104 , either directly or indirectly. The speed sensor  2116  (e.g., rotational encoder, Reed switch) may be an integral part of the tractor-trailer  100  as manufactured by the vehicle manufacturer, used as part of the speedometer of the tractor-trailer  100 . Alternatively, the speed sensor  2116  may be added later, e.g. as a retrofit. In some implementations, the speed sensor  2116  is a dedicated part of the control subsystem  2100  and is unrelated to, or not part of, the conventional feedback system (e.g., speedometer) of the tractor-trailer  100 . 
     The processor(s)  2104  may receive signals indicative or representative of speed from an on-board computer  2118  associated with the tractor-trailer  100 . In an example, the on-board computer can be a truck engine management system configured to monitor one or more parameters of the vehicle. These on-board computers track various parameters of operation such as speed, distance, total time, elapsed time, and/or location. In an example, the truck engine management system and the processor(s)  2104  can obtain any/all parameters available including speed, temperature, gear, power, throttle position, fuel consumption, fuel rate, and brake pressure and position. In another example, the on-board computer may be a black box configured to receive and store one or more vehicle parameters. 
     The processor(s)  2104  may receive signals indicative or representative of speed from a global positioning system (GPS) receiver  2120 . The (GPS) receiver  2120  may determine location information indicative or representative of a current location of the tractor-trailer  100 . The processor may be configured to associate the location information with a particular road or section of road, and hence with a posted speed limited or expected speed of travel for the tractor-trailer  100 . For example, the processor  2104  may be configured to determine whether the tractor-trailer  100  is on a highway or a surface street based on the location information. 
     The processor(s)  2104  may receive signals indicative or representative of speed or location from a wireless receiver  2122 . The wireless receiver  2122  may be part of the control subsystem  2100 , or may be a dedicated part of the tractor-trailer  100 . The wireless receiver  2122  may determine speed information or location information indicative or representative of a current speed or location of the tractor-trailer  100 . For example, the wireless receiver  2122  may receive information indicating that the tractor-trailer  100  is at an entrance ramp or exit ramp of a highway, or at a toll booth or toll plaza associate with an entrance or exit of a highway. Additionally, or alternatively, the information may indicate another location along a highway or surface street. The location information may itself be indicative or representative of a posted speed. Additionally or alternatively, the received information may provide a measure of the actual speed of the tractor-trailer  100 , for example as measured by radar or laser speed sensors positioned along the road. The processor may be configured to associate the location information with a particular road or section of road, and hence with a posted speed limit or expected speed of travel for the tractor-trailer  100 . For example, the processor  2104  may be configured to determine whether the tractor-trailer  100  is on a highway or surface street based on the location information. 
     Additionally, the control subsystem  2100  may include one or more positional or orientation sensors  2124  which provides signals to the one or more processor(s)  2104  indicative or representative of the current positions or orientations of one or more components of the movable fairing assembly  150 , such as, for example, the lateral portions  150   a, b  and top portion  150   c . The positional or orientation sensors  2124  may be, for example, a proximity sensor, a Reed switch, a positional encoder, a rotational encoder, an optical encoder, or other like device that can sense the position or orientation of one or more components in the movable fairing  150 . The processor(s)  2104  may be configured to determine a correct position or orientation for each of the components of the movable fairing  150  in each of various configurations (e.g., fully retracted or fully unextended configuration, intermediate configurations, and fully deployed or fully extended configuration). The processor(s)  2104  may further be configured compare the current position or orientations for each component of the movable fairing  150  as indicated by the signals received from the positional or orientation sensors  2124  with the expected configuration or position for each component of the movable fairing assembly  150  to identify a potential error condition. Such an error condition may arise, for example, if the current configuration or position or orientation of one or more of the components of the movable fairing assembly  150  differs from the expected configuration or position or orientation for the one or more components. In some implementations, a time out period, such as may be stored in memories  2106 ,  2108 , may be used to determine if the movable fairing assembly  150  has successfully transitioned from the fully retracted or un-deployed configuration to the fully extended or fully deployed configuration or some intermediate configuration therebetween. If the processor  2104  determines that such an error condition exists (e.g., the positional sensors  2124  indicate that one or more components of the movable fairing assembly  150  have not reached the expected positions or orientations in the fully or partially deployed configuration within the timeout period), the processor may transition the movable fairing assembly  150 , if necessary, into the fully retracted or full un-deployed configuration. 
     The control subsystem  2100  may include one or more object sensors  2132  positioned and oriented to monitor regions in which a deployable fairing will deploy (i.e., deployed region), or alternatively encompass, when in the fully deployed or fully extended configuration. The deployed region may in some instances encompass or be encompassed by a gap region between two coupled vehicles (e.g., coupled tractor trailer combination). The deployed region may in some instances only those volumes in which a portion of the deployable fairing will reside when fully deployed or fully extended, for instance omitting a large central volume the is encompassed by the fully deployed fairing but which no fairing structure will reside. This allows a more refined determination of whether or not full deployment of the deployable fairing may cause a collision with some obstacle (e.g., structure on the trailer), where collision may result in damage to the fairing or even to the object or obstacle. 
     The object sensor(s)  2132  are communicatively coupled to provide signals to the processor(s)  2104 , either directly or directly, indicative or representative of whether there is an object or obstacle in the deployed region. In some implementations the object sensors will determine whether an object or obstacle is present or absent from the deployed region. In some implementations the processor(s)  2104  will determine whether an object or obstacle is present or absent from the deployed region. 
     The object sensor(s)  2132  can any of a variety of forms. For example, the object sensor(s)  2132  can include any one or more of: distance sensors  2132   a , proximity sensors  2132   b , image sensors  2132   c . Distance sensors may, for example, include one or more of: laser range finders, distance measuring devices or sensors. Proximity sensors may, for example, include one or more of: ultrasonic sensors, capacitive sensors, photoelectric sensors, inductive sensors or a magnetic sensors. Image sensors may, for example, include single digital cameras, binocular digital cameras, Vidicons, CMOS based image sensors, etc. It may be advantageous in some implementations to include at least one sensor of a first type of sensor and at least one sensor of a second type of sensor, the second type of sensor different from the first type of sensor. 
     The control subsystem  2100  may include one or more environmental sensors. 
     For example, the control subsystem  2100  may include one or more wind sensors  2134   a ,  2134   b  that detect wind speed, relative wind direction or both. The wind sensors  2134   a ,  2134   b  are communicatively coupled to provide signals to the processor(s)  2104  indicative or representative of wind speed (e.g., magnitude) and/or relative wind direction (e.g., cross wind relative to the vehicle). In some implementations, the wind sensors  2134   a ,  2134   b  determine the wind speed and the wind direction and provide that information to the processor(s)  2104 . In other implementations, the processor(s)  2104  determines the wind speed and/or the wind direction from information provided by the wind sensors  2134   a ,  2134   b.    
     For example, the control subsystem  2100  may include one or more temperature sensors  2136  position to determine a temperature in an ambient environment in which the vehicle is operating. The temperature sensors can take a variety of forms, for example thermocouples. The temperature sensors  2136  are communicatively coupled to provide signals to the processor(s)  2104  indicative or representative of temperature. In some implementations, the temperature sensors  2136  determines the temperature and provides that information to the processor(s)  2104 . In other implementations, the processor(s)  2104  determines the temperature from information provided by the temperature sensors  2136 . 
     In one implementation, the processor(s)  2014  use information from the object sensor(s)  2132  to determine whether the deployment region has any objects or obstacles that would hinder deployment or even result in damage. Such may be assessed for example before the start of a trip, for instance when a trailer is coupled to a tractor. This approach advantageously allows the system to accommodate various styles of trailer (e.g., reefer). Additionally or alternatively, such may be assessed one or more times during a trip, for instance periodically or in response to a change in conditions. This approach advantageously allows the system to accommodate any travel in the fifth wheel. 
     In operation, if the processor(s) determines that any object or obstacle is present, the processor can determine that deployment of the deployable fairing should either be prevented or limited to an intermediate configuration. Such determination may be based at least in part on a position or location of the object or obstacle. Deployment into an intermediate configuration means moving the deployable fairing to the intermediate configuration, or leaving the deployable fairing in the intermediate configuration, and stopping the deployment in the intermediate configuration. This is to distinguish over simply transitorily passing through an intermediate configuration while deploying to the fully deployed or fully retracted configurations. 
     In some implementations, the presence or absence of an object or obstacle in the deployment region is the only factor considered in determining whether to deploy the deployable fairing and into which configuration the deployable fairing will be deployed. Thus, the processor(s)  2014  may determine to deploy the deployable fairing to an intermediate configuration that places a distal end of the deployable fairing close, but short of the object or obstacle, for example leaving a safety margin to limit or eliminate the chance of damage. 
     In other implementations, the determination may take into account a variety of other factors, for example factors related to enhancing fuel efficiency. Factors may include vehicle speed, braking or change in vehicle speed, wind speed, wind direction and/or temperature in the ambient environment. 
     For example, a speed sensor  2116 , discussed herein, may provide a signal indicating that the tractor-trailer  100  is traveling at a relatively high speed, such as may occur when the tractor-trailer  100  is traveling over a highway or freeway. Alternatively, the processor(s)  2104  may rely on location instead of, or in addition to, vehicle speed in determining whether to deploy the deployable fairing. In this situation, the processor(s)  2104  may determine if the speed indicated by the signal from the speed sensor  2116  falls above a threshold speed value stored in memories  2106 ,  2108  or whether a present location corresponds to a highway versus a surface street. If the speed is above the threshold or the location corresponds to a highway, the processor(s)  2104  determines to deploy the deployable faring. The extent of deployment may depend on whether an object or obstacle is present in the deployment region. The processor(s)  2104  sends signals to control the valve  2126  to activate the actuator  2114  to deploy the deployable faring into the fully deployed configuration, or alternatively into an intermediate configuration if an object or obstacle is present. In these modes of operation, the processor(s)  2014  may perform a real-time assessment of whether there is an object or obstacle in the deployment region, and/or may rely on a previously stored assessment, for instance an assessment when a trailer is first coupled to a tractor. 
     Also for example, the speed sensor  2116 , discussed herein, may provide a signal indicating that the tractor-trailer  100  is traveling at a low speed, such as may occur when the tractor-trailer  100  is traveling over surface streets. Alternatively, the processor(s)  2104  may rely on location, determining that the vehicle is on a surface street or not on a highway or freeway. In this situation, the processor  2104  may determine if the speed indicated by the signal from the speed sensor  2116  falls below a threshold speed value stored in memories  2106 ,  2108 . If the vehicle speed is below the threshold speed or the current position indicates that the vehicle is on a surface street or parking lot, then the valve  2126  may be used to deactivate the actuator  2114 . 
     The processor  2104  may optionally receive signals from various other sensors that result in the valve  2126  being used to activate or deactivate the deployable fairing  16 . For example, the processor  2104  may receive signals from one or more wind sensors, for instance one or more wind speed sensors  2128   a , and/or one or more wind direction sensors  2128   b  indicating a speed and direction of wind, for instance a strength of a cross wind. The processor  2104  may determine whether the wind speed and/or direction exceed a cross wind threshold. For example, the processor  2104  may receive signals from one or more a temperature sensors  2130 , indicating a temperature of the environment around the actuator  2114 . The processor  2104  may determine whether the sensed temperature falls below a low temperature threshold or exceeds a high temperature threshold. In some implementations, the processor  2104  may use the valve  2126  to activate or deactivate the actuator  2114 . 
     The processor(s)  2104  then determines which intermediate configuration is safe, and sends signals to one or more actuators to deploy the deployable faring to the identified intermediate configuration, stopping in the intermediate configuration. 
     Whether independent of vehicle speed or in conjunction with vehicle speed, the processor(s)  2104  may determine to deploy the deployable fairing in response to wind speed, wind direction and/or temperature in the ambient environment. In each instance, the processor(s)  2104  may determine to not deploy the deployable fairing or to move the deployable fairing to the fully retracted or fully un-deployed configuration is an objector or obstacle is present in the deployment region. Alternatively, the processor(s)  2104  may determine which intermediate configuration is safe in light of the presence of an object or obstacle in the deployment region, and sends signals to one or more actuators to deploy the deployable faring to the identified intermediate configuration. 
     The foregoing has been a detailed description of illustrative embodiments of the invention. Various modifications and additions can be made without departing from the spirit and scope of this invention. Features of each of the various embodiments described above may be combined with features of other described embodiments as appropriate in order to provide a multiplicity of feature combinations in associated new embodiments. Furthermore, while the foregoing describes a number of separate embodiments of the apparatus and method of the present invention, what has been described herein is merely illustrative of the application of the principles of the present invention. For example, although a tractor-trailer is depicted, the fairing system can be implemented into any kind of vehicle having a cab and a trailer. Additionally, as used herein, the terms “process” and/or “processor” should be taken broadly to include a variety of electronic hardware and/or software based functions and components (and can alternatively be termed functional “modules” or “elements”). Moreover, a depicted process or processor can be combined with other processes and/or processors or divided into various sub-processes or processors. Such sub-processes and/or sub-processors can be variously combined according to embodiments herein. Likewise, it is expressly contemplated that any function, process and/or processor herein can be implemented using electronic hardware, software consisting of a non-transitory computer-readable medium of program instructions, or a combination of hardware and software. Additionally, as used herein various directional and dispositional terms such as “vertical”, “horizontal”, “up”, “down”, “bottom”, “top”, “side”, “front”, “rear”, “left”, “right”, and the like, are used only as relative conventions and not as absolute directions/dispositions with respect to a fixed coordinate space, such as the acting direction of gravity. Additionally, where the term “substantially” or “approximately” is employed with respect to a given measurement, value or characteristic, it refers to a quantity that is within a normal operating range to achieve desired results, but that includes some variability due to inherent inaccuracy and error within the allowed tolerances of the system (e.g. 1-5 percent). Accordingly, this description is meant to be taken only by way of example, and not to otherwise limit the scope of this invention.