CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application claims the benefit of U.S. Provisional Application No. 60/771,966, filed on Feb. 10, 2006. The disclosure of the above application is incorporated herein by reference. 


   FIELD 
   The present disclosure relates to reclamation of wasted energy in a vehicular application, and in particular to the recovery and storage of energy in form of braking torque potential energy resulting from the deceleration of a vehicle which may be subsequently provided to a stationary storage source or distributed into a power grid or used as a secondary power source for emergency backup applications. 
   BACKGROUND 
   The statements in this section merely provide background information related to the present disclosure which may not constitute prior art. 
   Land-based vehicles, e.g., over-the-road (OTR) vehicles such as tractor semi-trailer rigs, represent an abundant resource of potential energy that is presently not being recovered. Specifically, in the course of travel, the deceleration of such vehicles is accomplished by a frictional load imposed on the power train either by a braking system or through back driving the transmission and engine of the vehicle. Thus, the energy utilized to decelerate the vehicle is either lost through heat dissipation or through non-productive operation of the vehicle&#39;s motor. 
   The opportunity for energy recovery becomes significant when one considers the number of OTR vehicles which travel the roads of the United States in a given day. With the multitude of trucks traveling the interstates to transport goods to various destinations, a significant source of energy recovery could be provided by a power generating system which efficiently and effectively recovers and stores this otherwise lost energy. Accordingly, there is a need in the art to provide a useable power generating system for land-based vehicles such as an OTR vehicle for recovery and storage of potential energy. 
   SUMMARY 
   An energy recovery and storage system is described herein which is readily adaptable to land-based vehicles and in particular OTR vehicles. In addition, a method or sequence of operations is provided which permits the efficient recovery and storage of brake torque energy without adversely effecting the operation of the vehicle in other modes of operation. Such a power generating system includes a power generating unit adapted to be secured to the undercarriage of a vehicle. The power generating unit includes a wheel which is positionable to selectively contact the road surface based on the operational state of the vehicle. The generator wheel is rotatably coupled to a generator or alternator which converts the rotational energy from the wheel into electrical energy. Alternately, the power generating unit includes a wheel which is continuously in contact with the road surface, and selectively coupled to the generator or alternator through a clutch mechanism. The power generating unit is electrically coupled to a storage battery carried onboard the vehicle for storage of the recovered electrical energy. The vehicle may further be equipped with a solar cell array as an auxiliary power recovery source which may also be coupled to the battery array for further storage of electrical energy (i.e., trickle charge battery). 
   When the vehicle has reached its destination, the energy stored in the battery may be electrically coupled to a stationary storage device such as a stationary battery array. As such, the electrical energy from the on-board storage battery array is discharged into the stationary battery array or connected to a stationary generator where it becomes usable at that local site. The stationary storage battery may also be electrically coupled to a power grid where the energy may be sold and discharged into the power grid. Alternately, the electrical energy in the stationary storage battery may be used to operate circuits or equipment at the discharge site. In the event of poor grid failure, multiple trailers could be coupled together to provide a safe reliable emergency source of electrical energy from the on-board storage array to support the discharge location allowing it to remain operating until power is restored. Large distribution centers where hundreds of trailers are located could supply enough energy to become a utility substation. 
   Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 


   
     DRAWINGS 
     The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way. 
       FIG. 1  illustrates a tractor semi-trailer rig with a power generating system; 
       FIG. 2  is a detailed view showing the power generating unit secured to the semi-trailer positionable between a raised idle position and a lowered activated position; 
       FIG. 3  is a cross-section taken along line III-III as shown in  FIG. 1 ; 
       FIG. 4  is an isometric view of the semi-trailer illustrating the various components of the power generating system; 
       FIG. 5  is a schematic illustrating a controller incorporated into the power generating system; 
       FIG. 6   a  is a flowchart illustrating the method employed by the power generating system to recover and store electrical energy; and 
       FIG. 6   b  is a flowchart illustrating an alternate method employed by the power generating system to recover and store electrical energy. 
   


   DETAILED DESCRIPTION 
   The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. 
   As described herein a power generating system  10  is provided on and over-the-road (OTR) vehicle  12  which includes a tractor  14  and a semi-trailer  16 . The power generating system  10  includes a power generating unit  18  coupled to the bottom of semi-trailer  16  by a support  20 . The power generating unit  18  includes a generator wheel  22  rotatably coupled to a power generator  24 . The power generator may take the form of a generator, an alternator or other means for converting rotational motion to electrical energy. A storage battery  26  is carried onboard the semi-trailer  16  preferably in the form of a battery array located within the floor  28  of the semi-trailer  16 . The storage battery  26  is electrically coupled to the generator  24 . The power generating system  10  may optionally include other means for generating electrical energy. In this regard, a solar panel array  30  may be located on the roof  32  of the semi-trailer  16 . The solar panel array  30  is electrically coupled to the storage battery  26  such that additional electrical energy generated by the solar panel array  30  is stored in the storage battery  26 . The potential for, additional energy for, charging could be derived from an oversized alternator mounted on engine of tractor. 
   As previously described, the power generating unit  18  is supported beneath the semi-trailer  16  by support  20 . As best seen in  FIG. 3 , support  20  is provided with an actuator operable to selectively activate the power generator  24 . In one embodiment, the actuator includes a mechanism  34  which is operable to vertically position the power generating unit  18  from a lowered position (shown in solid lines) wherein the generator wheels  22  contact the road surface R to a raised position (shown in phantom lines) wherein the generator wheels  22  is positioned out of contact from road surface R. In another embodiment, the actuator includes a clutch mechanism  42  which is operable to couple the generator wheel  22  with the power generator  24 . One skilled in the art will recognize that these embodiments of the actuator may be used alone or in combination. 
   The mechanism  34 , as illustrated in  FIG. 3 , is a linkage mechanism having a pair of links  36  extending between the support  20  and the generating unit  24  and an actuator  38  operably coupled to linkages  36  for selectively positioning the power generating unit  18 . While mechanism  34  has been shown and described as an actuated linkage mechanism, it should be appreciated that other suitable means for vertically positioning the power generator  24  may be employed. In this regard, the mechanism  34  must be suitable to vertically position the power generating unit  18  to place the generator wheels  22  into contact with the road surface R and maintain such contact. 
   The power generating system  10  as described above is operable in the following manner. In the course of driving, the engine (not shown) of OTR vehicle  12  drives the vehicle along road surface R during the majority of the travel time, the brake torque potential energy is minimal since the motor is driving the vehicle  12 . In such circumstances, the power generating unit  18  is de-activated. For example, the power generator  24  is vertically positioned in a raised position (as shown in  FIG. 1  and as shown in phantom lines in  FIGS. 2 and 3 ). In the raised position the generator wheels  22  of the power generating unit  18  are out of contact from the road surface R, and thus the power generating system  10  is in an idle mode of operation. Alternately, the clutch mechanism  42  is engaged such that rotational motion of the generator wheel  22  is uncoupled from the power generator  24 . 
   When an opportunity to recover brake torque potential energy occurs, mechanism  34  is actuated. For example, the power generator  24  is lowered vertically downward such that the generator wheels  22  come into contact with the road surface R. Such contact between the generator wheels  22  and the road surface R causes the generator wheel  22  to rotate. As a result, the generator shaft  40  which is coupled to the generator wheels  22  rotates, thereby generating electrical energy. The electrical energy reclaimed from the power generating unit  18  is directed into the storage battery  26  where it is stored for subsequent use. Alternately, the clutch mechanism  42  is disengaged such that rotational motion of the generator wheel  22  is coupled to the power generator  24 . 
   As noted above, the power generator  24  is operable based upon the opportunity to recover brake torque potential energy. Three such opportunities to recover such brake torque in the normal course of operation of a vehicle such as OTR vehicle  12  are generally known. These opportunities include (1) during deceleration of the vehicle such as when a braking system is applied in a conventional vehicle; (2) during downhill travel of the vehicle such as when a lower gear of the transmission might be utilized to back drive the motor in mountainness terrain; and (3) during stopping maneuvers when the vehicle is brought to a complete rest. Other opportunities to recover such brake torquing potential energy may be identified and available during the normal operation of OTR vehicle  12 . 
   As will be appreciated from the above description and illustrated in  FIG. 5 , the actuation of power generating system  10  may be controlled by control circuit  44  based upon the operational state of the vehicle, (e.g., accelerating, decelerating, steady state) or based upon the terrain over which the vehicle is traveling (e.g., flat roads, up hill or downhill). In its simplest form, the opportunity to recover brake torque potential energy may be evaluated by the operator of the vehicle  46 , who in turn would manually actuate the mechanism  34  to activate the power generating system  10 . Alternately, activation of the power generating system  10  may be automated by the control circuit  44  based upon input signals from various sources. For example, an accelerometer  48  could be utilized in conjunction with the power generating unit  18  to evaluate the current state of acceleration/deceleration of the vehicle. If the rate of deceleration is above a predetermined value, the actuators in the form of the position mechanism  34  and/or the clutch mechanism  42  could be actuated to bring the power generator  24  into its operational position. Alternately, certain sensors currently located onboard the OTR vehicle  12  could be employed to determine the operational state of the vehicle. For example, if the vehicle  12  is equipped with brake sensors  50 , the actuators may be controlled in a manner such that the power generator  24  is activated when a predetermined braking state or condition exists. Alternately, certain engine control sensors  52  such as the manifold absolute pressure (MAP) sensor  54  or an engine torque sensor  50  could be employed to evaluate the operational state of the motor such that the power generator  24  is activated when a predetermined condition or state of operation of the motor (for example when the motor is being back driven) exists. 
   Control of the power generating system  10  may also be implemented in a predictive manner. For example, the OTR vehicle  12  may be provided with a global positioning system (GPS)  58  to provide absolute global positioning data for the vehicle  12 . In addition, topological data  60  regarding the terrain over which the vehicle will travel in route to its destination may be provided such that the power generation system  10  may be controlled in response thereto. Specifically, with the global positioning system  58  and the topological data  60 , the power generating unit  18  can be activated when the control system predicts that the vehicle  12  will be traveling in a downhill direction. Predetermined set points may be provided which ensure that the power generation system  10  is only operated when the vehicle  12  is traveling down a road having a grade greater than a predetermined value. In any of the above given automated control sequences, it is anticipated that the vehicle operator could override such automated control. 
   Further details concerning the power generation system  10  become apparent upon consideration of how the system is implemented. For example, one benefit of the present invention is that it may be readily adapted to current semi-trailer applications. Specifically, the power generating unit  18  and in particular the support  20  may be designed so as to be easily retrofit onto existing semi-trailers. This further has the advantage of providing an efficient means for maintaining and servicing the power generating unit. Specifically, such units may be secured to the bottom of the semi-trailers with bolts or some more threaded fasteners such that it may be readily removed for maintenance repair. Likewise, the location of the power generating unit  18  may be appropriately positioned beneath the semi-trailer  16  as a function of the load distribution within the trailer.
The present disclosure is directed to a power generating unit secured beneath a semi-trailer on an over-the-road vehicle. The power generating unit is selectively positionable from a raised position to a lowered position wherein a generating wheel is in contact with the road surface for recovering brake torque potential energy during select operational states of the vehicle. A storage battery is carried on the vehicle trailer and in electrical communication with the generator to store such excess electrical energy. Periodically, the electrical energy is made available for discharging to a stationary storage battery for sale and distribution into the power grid as supplemental energy or alternately to provide a temporary power substation.