Abstract:
The invention described herein provides an energy transfer system via a tire based inductor system. By using the tire, the area inside the tire, the tire rim, or the wheel as the inductive pick-up for a powered roadway system the prior art problems are solved. Namely, since the tire/wheel is always in contact, or near contact with the road, the air gap is reduced to a minimum, and substantially fixed, distance. By mounting the secondary on the perimeter of a wheel, relative motion between the road and inductor is minimized In addition, the pick-up can be encased in the tire, eliminating the problem of road debris, snow and ice entirely. Also, some heating of the tire due to electrical losses may enhance traction and tread performance on snowy or wet roads. In all configurations, the vehicle&#39;s wheel suspension adjusts vertically adjusting for road imperfections and obstacles.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application is related to, claims the earliest available effective filing date(s) from (e.g., claims earliest available priority dates for other than provisional patent applications; claims benefits under 35 USC §119(e) for provisional patent applications), and incorporates by reference in its entirety all subject matter of the following listed application(s) (the “Related Applications”) to the extent such subject matter is not inconsistent herewith; the present application also claims the earliest available effective filing date(s) from, and also incorporates by reference in its entirety all subject matter of any and all parent, grandparent, great-grandparent, etc. applications of the Related Application(s) to the extent such subject matter is not inconsistent herewith.
       1. U.S. provisional patent application 61,410,385 entitled “Elastomeric Tire Secondary inductor for Inductive Power Transfer on Electrified Roadway”, naming Gary Flomenhoft as inventor, filed Nov. 5, 2010.       
 
       BACKGROUND 
       [0003]    1. Field of Use 
         [0004]    These teachings relate generally to a system and method for inductively coupling power to electric vehicles and more particularly to an apparatus and method for inductively coupling power through the tires, rim, or wheel of an electric, vehicle. 
         [0005]    2. Description of Prior Art (Background) 
         [0006]    Electric powered transportation is generally more efficient and less polluting than petroleum powered vehicles. Vehicles traveling on fixed routes such as subways, streetcars, and railroad trains often use electric motive power due to its efficiencies. These vehicles might use a catenary wire, overhead wire, or third rail system to transmit power to the vehicle. 
         [0007]    The capability to transmit electricity to vehicles enables electric vehicles to have nearly unlimited range without having to recharge onboard batteries or refuel with liquid hydrocarbons, e.g., gasoline for comparatively inefficient, internal combustion engines. For example, the average efficiency of an internal combustion engine in conversion of gasoline to motion is about 12-15% whereas electric vehicles convert, about 80-90% of electric power to motion. 
         [0008]    The primary limitation for electric vehicles such as cars and trucks has been the storage or transmission of electricity onboard the vehicle. For example, lithium batteries typically used for powering electric vehicles contain 100 WH/kg and take hours to recharge. 
         [0009]    The primary solutions currently being proposed for electric vehicle transportation are better batteries and faster charging, battery swapping systems, and plug-in hybrid vehicles. Each one has their limitations and will not solve the problem of electric vehicle transportation in the long run. 
         [0010]    Batteries and fast charging: in general, the time for charging lithium-ion batteries is unacceptable for mainstream usage. Even if lithium-ion batteries could be theoretically recharged in 5 minutes, the infrastructure needed to transmit the tremendous currents needed for fast charging, on the order of 2000 Amps for each vehicle, is unrealistic and not feasible. 
         [0011]    Battery Swapping: Battery swapping could theoretically solve the problem of fast energy replacement in electric vehicles, but the standardization required has no precedent (consider electric hand tools), the logistics are unwieldy, and it was explored during the 1990&#39;s unsuccessfully. It also fails the criteria of being a superior system to current technology. 
         [0012]    Plug-in hybrid Vehicles: Plug-in hybrid vehicles run primarily by electric, power, with internal combustion back-up combining the best features of both. In the short term they dramatically increase the efficiency of vehicles by running mainly on electric power, and using internal combustion power as a backup or secondary power source. Hybrid vehicles may serve as a transitional vehicle to a pure electric vehicle future. But in the long run they fail the criteria of avoiding petroleum. Even using bio-fuel they still use the inefficient internal combustion engine. 
         [0013]    Other prior art solutions to powering electric vehicles include inductively coupling power from an electrified roadway across an air gap to the electric vehicle. However, it will be appreciated that the feasibility of transmitting power to vehicles through induction using wires buried in the roadway has been proven indoors and in warm, sunny climates such as California and Florida where an inductive pickup is positioned such that the maximum air gap is 10 cm. 
         [0014]    However, the problem of an inductive, pick-up hanging under the car close to the road in snow and ice is a previously unsolved problem. It will be appreciated that such an arrangement is unsuitable for any less-than-ideal road conditions since the pick-up would be subject to road debris, snow and ice during, had weather. 
         [0015]    More recent prior solutions have placed the secondary pick-up at a greater distance from the road, such as 5 inches, to avoid contact with debris. The greater air gap has the disadvantage of lower transmission efficiency. 
       BRIEF SUMMARY 
       [0016]    The foregoing and other problems are overcome, and other advantages are realized, in accordance with the presently preferred embodiments of these teachings. 
         [0017]    The characteristic of an inductor such as found in electric motors, generators, or magnets is an insulated copper wire or bar wound around a ferrous metal pole Or poles to increase magnetic flux. A radial tire contains plain steel metal belts. In one embodiment of this invention, steel belts within a tire can be used to serve as the pole of an inductor. Copper wire wound around the tire&#39;s internal steel belts create an inductor, which serves as the secondary pick-up for an electric powered roadway vehicle. Since there are typically four tires on the vehicle, the power requirements for each tire can be reduced by four if all four tires employ this invention. Slip rings or other rotating electrical transmission system devices that are well known can then be used to conduct the electricity to an electric drive system. 
         [0018]    In another embodiment of this invention, ferrous materials other than a tire&#39;s steel belts are used in the tire to create an integral inductor. The inductor material can be added within the tires structure, added to the inside of the tire, supported in the space between the tire and rim (as one example, supported by an inner tube), or attached to or supported by the rim. Such embodiments would be applicable for vehicle or tire types that do not typically incorporate one or more steel belts, or could be a way of retrofitting the capability to vehicles without tires with an integral inductor. 
         [0019]    In accordance with one embodiment of the present invention an apparatus for inductive power transfer on an electrified roadway is provided. The apparatus includes a steel belted radial tire; and, an insulated electric wire, wherein the insulated electric wire is wrapped around the steel belt to form an in-tire inductor. The insulated electric wire may be any suitable electric wire such as copper wire. 
         [0020]    Another embodiment includes the use of magnetic materials embedded in the tire itself such as iron or ferrite particles forming a composite with vulcanized rubber or elastomeric composites. 
         [0021]    The invention is also directed towards a method for inductive power transfer to an electric vehicle on an electrified roadway. The method includes collocating an inductive pick up device within the electric vehicle&#39;s tire in contact with the roadway. The method further includes inductively coupling power from the electrified roadway via the inductive pickup; and, driving an electric drive motor with the inductively coupled power. 
         [0022]    In accordance with another embodiment of the present invention a shielded mobile inductor system for inductively coupling power from an electrified roadway is provided. The system includes at least one tire; and, at least one inductor positioned integral with the at least one tire. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0023]    The subject matter which is regarded as the invention is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other objects, features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which: 
           [0024]      FIG. 1  is a schematic diagram illustrating one embodiment of the present invention of an inductive power transfer apparatus embedded within electric vehicle tires on an electrified roadway; 
           [0025]      FIG. 2  is a cross section schematic diagram illustrating implementation of an inductor pickup within a steel belted radial tire in accordance with the invention shown in  FIG. 1 ; 
           [0026]      FIG. 2A  is a top view cutaway in accordance with the invention shown in  FIG. 2 ; 
           [0027]      FIG. 2B  is a rim mounted inductive pickup in accordance with the present invention shown in  FIG. 1 ; 
           [0028]      FIG. 2D  is a pictorial illustration of an air cote configurations of the inductive pickup in accordance with the present invention shown in  FIG. 1   
           [0029]    FIG.  2 D 1  is a pictorial illustration of an inductive pickup with a secondary air core in accordance with the present invention shown in  FIG. 1D   
           [0030]      FIG. 2C  is a pictorial illustration of the rim mounted inductive pickup  2 B 1  in accordance with the present invention shown in  FIG. 2B ; 
           [0031]    FIG.  2 E 1  is a pictorial illustration of an inductive pickup with a secondary ferrite core in accordance with the present invention shown in  FIG. 1 ; 
           [0032]    FIG.  2 F 1  is a pictorial illustration of multiple configurations of the inductive pickup in accordance with the present invention shown in  FIG. 1 ; 
           [0033]      FIG. 3  is a block diagram illustrating the power train and controls for an electric vehicle in accordance with the invention shown in  FIG. 1 ; 
           [0034]      FIGS. 4A-4E  are pictorial diagrams showing alternate embodiments for implementing an inductive pick up in accordance with the invention shown in  FIG. 1 ; and 
           [0035]      FIG. 5  is a method flow chart for determining power sourcing in accordance with the invention shown in  FIG. 3 . 
       
    
    
     DETAILED DESCRIPTION 
       [0036]    Referring now to  FIG. 1 , there is shown a schematic diagram illustrating one embodiment of the present invention of an inductive power transfer apparatus embedded within electric vehicle tires  106  on an electrified roadway  107 , The energy transmission arrays  105  are preferably disposed beneath a roadway surface, although transmission systems disposed on the surface are contemplated as well. The embedded energy reception system  106  is on one or more axels of vehicle  101 , which uses the transferred electrical power to either charge an onboard energy storage device unit ( FIG. 3 , item  18 ) or for propulsion/use directly. It will also be that any suitable number of embedded energy reception system  106  configurations may be employed, such as a “fifth” wheel  104  mechanically linked to vehicle  101  via mechanical linkage  104 A shown in  FIG. 1   
         [0037]    Referring also to  FIG. 2 , there is shown is a cross section schematic diagram of electric vehicle tires  106  illustrating implementation of an inductor pickup within a steel belted radial tire in accordance with the invention shown in  FIG. 1 . Copper wires  21 , or any suitable wiring, are wound around metal belts  23  forming an inductive pick up. It will be appreciated, and discussed herein, that any suitable inductive pickup may be located within internal tire wall  27 , within tire bead  29 , within tread area  25 , or on the rim or wheel, or otherwise proximal to an inner or outer surface of the tire. It will be appreciated that the inductive pickup positioned within and near the outer surface of the tire minimizes the air gap, or distance, between the inductor pickup and the electrified roadway  107  and advantageously maximizes the coupling efficiency between the electric vehicle tires  106  and electrified roadway  107 . 
         [0038]    Referring also to  FIG. 2A  there is shown a top view cutaway in accordance with the invention shown in  FIG. 2 . Copper wires  21 , or any suitable wiring, are wound around metal belts  23  forming an inductive pick up; forming, or generating, when electrified, magnetic field lines  2 A 1  axial to electric, vehicle tires  106 . 
         [0039]    Referring also to  FIG. 2B  there is shown a cutaway view of tire  2 B 5  with rim  2 B 3  mounted inductive pickup in accordance with the present invention shown in  FIG. 1 . Copper wires  2 B 2 , or any suitable wiring, are wound around inductor core  2 B 1  forming an inductive pick up; forming, or generating, when electrified, magnetic field lines  2134  transverse to electric vehicle tires  106 . 
         [0040]    Referring also to  FIG. 2C  there is shown a pictorial illustration of the rim mounted inductive pickup  2 B 1  attached to tire rim ( FIG. 2B : item  2 B 3 ). It will be appreciated that tire  2 B 5  may be any suitable tire. 
         [0041]    Referring now to FIG.  2 D and  2 D 1  there is shown one configuration of the inductive pickup in accordance with the present invention shown in  FIG. 1 . FIG.  2 D 1  shows a single wheel mounted air core defined by conductive wires  2 D 22 . Also shown in FIG.  2 D 1  is a roadside primary inductor  2 D 20  wrapped by conductive wires  2 D 21 . Flux lines  2 D 23  are generated when conductive wires  2 D 21  are electrified by a suitable current alternating at to suitable frequency. It will be further understood that conductive wires  2 D 21  and  2 D 22  may be any suitable conductive wire, such as, for example, Litz wire in order to operate at high frequencies.  FIG. 2D  is a pictorial side view of a tire rim  2 D 10  with an air core configuration defined by winding loop  2 D 30 . 
         [0042]    Referring now to FIG.  2 E 1  and FIG.  2 F 1  there is shown multiple configurations of the inductive pickup M accordance with the present invention. FIG.  2 E 1  shows a single wheel mounted inductor core  2 E 11  wrapped by conductive wires  2 E 10 . It will be appreciated that core  2 E 11  may be any suitable core. Also shown in FIG.  2 E 1  is the roadside primary inductor  2 E 13  wrapped by conductive wires  2 E 12 . Flux lines  2 E 14  are generated when conductive wires  2 E 12  are electrified by a suitable current alternating at a suitable frequency. It will be further understood that conductive wires  2 E 10  and  2 E 12  may be any suitable conductive wire, such as, for example, Litz wire in order to operate at high frequencies. 
         [0043]    Still referring to FIG.  2 F 1  there is shown a single winding configuration  2 F 10  with conductive wire  2 E 10  around all rim mounted cores  2 E 11 . Another configuration  2 E 12  shows conductive wire  2 E 10  around a subset of the rim mounted cores  2 E 11 . Finally, configuration  2 F 14  shows conductive wire  2 E 10  around each of the rim mounted cores  2 E 11 . Also shown in FIG.  2 F 1  are roadside, or off vehicle, primary cores  2 E 13  and conductive wire  2 E 12 . 
         [0044]    Referring also to  FIG. 3 , there is shown a block diagram illustrating the power train and controls for an electric vehicle in accordance with the invention shown in  FIG. 1 . The power train and controls  10  of the present invention includes a battery pack  18 , an electric drive motor  16  powered by the battery pack  18  and an optional internal combustion engine  24 . A controller  22  determines the prime mover of the vehicle, i.e., whether the electric motor  16  is powered by battery pack  18  or power inductively coupled from energy transmission arrays  105  via inductive power transfer apparatus embedded within electric vehicle tires  106 . Where an internal combustion engine, or other non-electric power source is available the controller will determine a priority power sourcing scheme dependent on power requirements and available power, discussed further herein. 
         [0045]    The power train and controls  10  includes a pair of inductive power transfer apparatus embedded within ground engaging drive wheels electric vehicle tires  106 . The wheels  106  could be either the rear wheels or the front wheels of the vehicle. In addition, it is within the scope. of the present invention to have the inductive power transfer apparatus embedded within ground engaging non-drive wheels such as a “fifth” wheel ( FIG. 1 , item  104 ). 
         [0046]    The wheels  106  are mechanically connected by a drive axle  13  to a differential  14 , the housing of the differential  14  being attached to a housing of a transmission (not shown). The transmission may be controlled in a conventional manner, such as, for example, by a gear shift lever or automatic transmission. 
         [0047]    The power train and controls  10  also includes an optional internal combustion engine  24 . An electric clutch  26  positioned between the electric motor  16  and the engine  24  will allow the engine  24  to assist in driving the wheels  12  if the controller  22  determines that the electric motor  16  needs assistance. Similarly, the battery pack  18  may be supplemented with inductive power derived from energy transmission arrays  105  via inductive power transfer apparatus embedded within electric vehicle tires  106 . Alternatively, the inductive power derived from energy transmission arrays  105  via inductive power transfer apparatus embedded within electric vehicle tires  106  could be designated as the prime power source with supplemental power from battery pack  18  as required. 
         [0048]    For example, if controller  22  determines that the electric motor  16  is not capable of accelerating the vehicle, due to loss of inductive power derived from energy transmission arrays  105  via inductive power transfer apparatus embedded within electric vehicle tires  106 , the controller  22  will cause the power derived from the battery pack to be brought on line, as described below, to assist in accelerating the vehicle  101 . 
         [0049]    Similarly, if controller  22  determines that the battery pack  18  and the inductive power derived from energy transmission arrays  105  via inductive power transfer apparatus embedded within electric vehicle tires  106  is not sufficient to power the electric drive motor  16  to accelerate the vehicle  101 , then, if available, combustion engine  24  may be engaged to provide supplemental power. 
         [0050]    While the battery pack  18  may assist powering the electric motor  16  if needed, it may not desirable to use the battery pack  18  in this fashion since accelerating the vehicle with the battery pack  18  depletes the battery pack  18 . It will be appreciated that it may be desirable to maintain the battery pack  18  at maximum charge for use when inductive power is not available. 
         [0051]    If at any time during the driving of the vehicle  101  the controller  22  senses that surplus power is available, either from the inductively coupled power  106  or the optional combustion engine  24  that surplus power may be used to charge battery pack  18  an accessory battery  30 . 
         [0052]    The controller  22  includes an optional regulator control  34  which controls the voltage output of the alternator  28 . The regulator control  34  adjusts the voltage of the alternator  28 . 
         [0053]    Still referring to  FIG. 3 , DC-DC converter  30 A charges the accessory battery  30  as required. 
         [0054]    Referring also to  FIG. 4A-4E  there are shown pictorial diagrams showing alternate embodiments for implementing the inductive pick up  105  in accordance with the invention shown in  FIG. 1 .  FIG. 4A  shows the inductor  4 A 1  imbedded within tire material  4 A 2 .  FIG. 48  shows inductor  4 A 1  adjacent to tire material  4 A 2 .  FIG. 4C  shows inductor  4 A 1  adjacent to tire material  4 A 2  and held in place by inflated inner tube  4 C 1 . Finally,  FIG. 4D  shows inductor  4 A 1  adjacent to tire material  4 A 2  and supported by bracket  4 D 2  and interior of wheel  4 D 1 .  FIG. 4E  shows a rim mounted configuration where inductor pickup  4 E 1  is mounted to tire rim  4 E 2 . 
         [0055]    Referring also to  FIG. 5  there is shown a method flow chart for one way of determining power sourcing in accordance with the invention shown in  FIG. 3 . As shown in  FIG. 5  when the vehicle is accelerated or power is otherwise required  51  the controller  22  determines  52  if power derived from transmission arrays  105  via inductive power transfer apparatus embedded within electric vehicle tires  106  is sufficient to power the electric drive, motor  16  to accelerate the vehicle  101 . if inductive power via the pathway described is not sufficient the controller  22  determines  57  if battery power from battery pack  18  coupled with inductive power is sufficient to power the electric drive motor  16  to accelerate the vehicle  101 . If decision  57  determines that inductive power coupled with battery power is not sufficient to power the electric drive motor, for example, if the vehicle  101  is not traveling on an electrified roadway, controller determines  502  if the battery pack  18  is capable of powering the electric drive motor  16 . If the battery pack  18  operating independently cannot provide sufficient power than controller  22  engages  59  optional combustion engine  24 . 
         [0056]    Still referring to  FIG. 5 , if controller  22  determines that there is sufficient inductive power then electric motor  16  is powered  52  by inductive power alone. It will be appreciated that this powering scheme or profile conserves battery power until battery power is required. Further controller  22  determines  54  if there is excess power available and if the battery is below minimum charge  56 . If below minimum charge than battery pack  18  is charged with excess inductive power  55 . 
         [0057]    It should be understood that the foregoing description is only illustrative of the invention. Thus, various alternatives and modifications can be devised by those skilled in the art without departing from the invention. Accordingly, the present invention is intended to embrace all such alternatives, modifications and variances that fall within the scope of the appended claims.