Abstract:
A system for harnessing wind energy to charge the electric storage battery of a vehicle, whether the vehicle is parked or in motion. While the vehicle is being driven, a roof-mounted, internal wind turbine harnesses wind energy and causes rotation of the shaft of an electric generator mounted to an interior surface of the roof. For charging the battery while the vehicle is parked, an external wind turbine is storable in the vehicle when not in use and attaches to the internal wind turbine. Cups of the kind used in cup anemometers are attached to radial arms that extend from an external shaft of the external wind turbine and catch ambient wind currents while the vehicle is parked, causing the external shaft and the generator shaft to rotate.

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATION 
     This application is a continuation in part of co-owned prior filed application entitled “Wind Turbine for Electric Car” of Peter W. Ripley, the sole owner and inventor of this application, Ser. No. 13/506,733, filed 14 May, 2012, now U.S. Pat. No. 8,513,828, issued Aug. 20, 2013, which is incorporated by reference herein in its entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates generally to devices for charging an electric battery of a motorized vehicle, and more particularly to devices for harnessing wind energy to charge an electric battery of an electric car. 
     2. Background Art 
     As used here, the term “electric car,” “hybrid electric,” “hybrid gas/electric,” “all electric motor,” and “all-electric vehicle” and “hybrid motor vehicle” refers to any motor vehicle that is powered substantially, in-part, and/or exclusively by an electric drive train. Hybrid motor vehicles with a drive train powered by an internal combustion engine in combination with one or more electric motors are now common on our streets and highways, but public acceptance of all-electric vehicles has been relatively slow. The slow acceptance of all-electric vehicles is largely due to the limited driving range such vehicles are currently capable of on a single charge of their electric storage batteries. 
     In addition, currently, there are relatively few places accessible to the public for recharging the batteries of an all-electric vehicle compared to the number of gasoline and diesel refueling stations. Further, the time required to recharge the batteries is significantly longer than the time required to fill the fuel tank of a vehicle that runs on gasoline or diesel fuel. Driving an all-electric vehicle beyond its rated driving range and to a location that lacks suitable battery charging facilities would likely mean incurring the time and expense for tow truck assistance before the driver could be underway again. 
     To address these challenges for electric and hybrid motor vehicles, and to promote public acceptance of battery-powered hybrid and all-electric cars and vehicles, it would be desirable to harness wind energy to help maintain some of the charge in the electric storage battery of all types of vehicles having one or more batteries, including for example hybrid gas/electric vehicles, electric cars, and all-electric vehicles, while the vehicle is being driven, as well as to charge the battery by harnessing wind energy while the vehicle is parked. 
     U.S. Pat. No. 7,886,669 B2 discloses a method for harnessing wind energy to charge a system battery that powered a limited number of electronic components of a stationary locomotive after engine shut down or while the locomotive coasts under gravity with its engine shut down. Those components can include lights and on-board monitoring and display systems of the locomotive. 
     This method also describes an electric device, such as a motor that could be run in an electrical generator mode. The motor can be coupled to an airflow device rotatable by ambient air flow. A controller is also included to activate the airflow device and generator when some minimum rotational speed of the airflow device occurs. For instance, the airflow device can be fan blades driven by the electric device to provide cooling. The airflow device can also harness ambient wind energy to drive the electric device to generate electricity for the electronic components or battery charging. 
     U.S. Pat. No. 7,828,091 B2 discloses an all electric vehicle having an internal wind turbine generator mounted in the nose of the vehicle. The generator uses compressed air and a high voltage battery to generate electricity to power the DC motors that drove the vehicle. When available wind energy was inadequate, compressed air stored in one or more air tanks is required to drive an air motor coupled to an electric generator to generate electricity, which recharges the electric battery and/or powers the DC motors. 
     The devices known in this technical field have been limited for use to specialized electric vehicle applications, and have not been able to efficiently harvest wind energy for use with more commonly available electric vehicles, such as electric automobiles. For example, the device used with locomotives employs wind devices that are not suitable for use with electric automobiles because of the need to be integrated into existing blowers, or which must protrude outside the locomotive. 
     The wind turbine generator variant is designed to be mounted about a front end of what appears to be the electric motor of an automobile, and is not suited for efficient harvesting of wind energy passing around the vehicle. Either of these types of systems require a high level of technical expertise and knowledge of the host vehicle to incorporate, maintain, repair, and/or upgrade the electricity generation capability. 
     New methods and devices are needed to more efficiently harvest energy from an airstream to generate electricity for use with electric vehicles. Also needed are devices that are less complex, and which are not limited to use in specialized applications. What is needed are devices that can be adapted for use with a wider range of electric vehicles, especially consumer automotive vehicles. It would also be advantageous if wind energy harvesting methods and systems were available that are usable by users who may not have very advanced technical training and knowledge of how to install, maintain, and operate such methods and devices. 
     SUMMARY OF THE INVENTION 
     The present invention provides a system for charging an electric storage battery of an electric motor vehicle such as an automobile. In one configuration, the system efficiently harvests wind energy from the airstream moving across a vehicle roof during forward motion. In other arrangements, the system uses attachments to harvest wind energy when the vehicle is stationary. In all variations, the system is adapted to mount conformally about the roof of the vehicle without substantial alterations thereto. 
     Additionally, the system incorporates easily serviceable configurations enabling electric vehicle operators to maintain, upgrade, and operate the system without the need for a high level of technical knowledge, training, and expertise. 
     The charging system includes a first wind turbine internally arranged within a housing, which is mounted to the roof of the vehicle. The internal wind turbine is intended to provide electric current charge to the vehicle&#39;s electric storage battery while the vehicle is in motion. 
     The invention further includes a second, external wind turbine that also mounts to the external to the first turbine assembly and/or the roof exterior. The second wind turbine enables electric current charge to the vehicle&#39;s electric storage battery while the vehicle is stationary or parked. The term “external” here signifies that the second, external wind turbine, is external to both the vehicle and the housing of the first wind turbine. 
     The internal wind turbine housing includes a bottom panel that extends across and attaches to the roof of the vehicle from a front end to an opposite rear end. The bottom panel is dimensioned and contoured to conformally overlie the vehicle roof, and includes a through hole that aligns with a hole in the vehicle roof. 
     The housing further includes an air inlet opening that overlies the front end of the bottom panel, an air outlet opening that overlies the rear end of the bottom panel, and an air flow corridor attached to the bottom panel that extends between, and joins, the air inlet and outlet openings. The air flow corridor comprises an entryway portion in communication with the air inlet opening, a discharge portion in communication with the air outlet opening, and a central portion that communicates with the entryway and discharge portions. 
     The entryway portion is contoured to conduct air entering the inlet opening while the vehicle is in forward motion toward the central portion. The central portion is contoured to conduct air around the internal wind turbine. The discharge portion receives the air from the central portion and conducts or communicates the air to the air outlet opening. 
     The internal wind turbine further includes a turbine blade assembly disposed within the central portion of the air flow corridor. The turbine blade assembly includes a hub that extends axially along a turbine shaft axis from a first, lower end to a second, upper end thereof and is rotatable about the axis. A plurality of turbine blades are distributed about the periphery of the hub, extending radially away from the hub normal to the turbine shaft axis. Each turbine blade also preferably has a weighted blade tip. 
     During operation of the internal wind turbine, the weighted tips increases the angular moment of inertia of the wind turbine. The increased moment of inertia stabilizes or manages the angular momentum of the spinning internal wind turbine to counteract buffeting and turbulence resulting from changes in air moving through the turbine. 
     The internal wind turbine also includes electric generator means, which includes an electric generator; means for attaching the electric generator to an inside surface of the roof of the vehicle; and means for coupling the shaft of the electric generator to the hub of the turbine blade assembly. The first wind turbine further includes a lid that extends longitudinally from a front end to an opposite rear end thereof. 
     The front end of the lid is pivotally attached to a front portion of the housing such that the lid is pivotable between a lowered, housing-covering position and a raised, open position. In its lowered position, the lid, in combination with the corridor, bottom panel and seal means, forms a closed compartment surrounding the turbine blade assembly, except for the air inlet and air outlet openings. 
     The internal wind turbine further includes locking means attachable to a rear end of the lid and to a rear portion of the vehicle for alternately securing the lid in a lowered, closed position and releasing the lid to a raised position. The turbine blade assembly may be removed from the housing to replace damaged blades, and to clean the housing. 
     To facilitate removal of the turbine blade assembly from the housing, the means for coupling the shaft of the electric generator to the hub of the turbine blade assembly preferably includes an adaptor with radially-directed splines that attaches to the shaft of the electric generator shaft by set screws. A hub shaft is included that extends axially though the hub and has a lower recess shaped and dimensioned to receive the adaptor splines in mating engagement. A removable pin inserts through aligned apertures in the hub and the hub shaft coupling them so they rotate together. 
     The blades preferably attach to the hub by threaded fasteners. This arrangement enables replacement of damaged blades. Blades are more easily replaced once the assembly has been removed from the splined adaptor and the vehicle. 
     The invention further includes an external wind turbine. The external wind turbine also enables harvesting wind energy, converting it into electrical current to charge the battery of the vehicle while the vehicle is stationary and/or parked. To enable installation of the second wind turbine, the lid has an opening where the turbine shaft axis (A-A) passes through the lid. 
     The housing incorporates a means to seal against moisture and air leaks. The seal means may include a disk-shaped, hub grommet disposed above and covering an upper portion of the hub. The grommet has an upstanding neck that extends up through the opening in the lid. A washer is mounted on the neck adjacent to an upper surface of the lid, and a cap seal mounts on the neck over the washer. 
     The external wind turbine includes an external shaft that extends from an upper end to an opposite, lower end along an external shaft axis, which shaft is rotatable about the axis. The external shaft is “external” when installed in an operating mode on the parked vehicle. When so installed, the shaft extends upward and externally from the housing to have only a lower end portion of the shaft extending into and internally within the housing. The external wind turbine further includes a plurality of radially or outwardly directed arms circumferentially spaced apart around the external shaft, wherein each arm has an inner end attached to the shaft and an opposite, outer end. 
     For “catching” the movements of ambient wind, a cup is attached to the outer end of each arm. Each cup has a concave inner surface and a convex outer surface that have a common peripheral edge defining the opening of the cup. The opening of each cup is generally orthogonal to and directed substantially along a tangent to the rotational path of the cups moving with the arms about the external shaft axis. The cups are positioned in an orientation to rotate about the external shaft axis and define a circular path during rotation. 
     The number of arms and cups is variable, but well-known in the art is a three armed variation, wherein each cup and respective arm are spaced apart at 120° intervals about the shaft axis. Thus, the external wind turbine resembles a cup anemometer in appearance and mechanical function. 
     The invention further includes means to couple the lower end of the external shaft to the hub for co-rotation therewith while maintaining the external shaft in coaxial alignment with the turbine shaft axis. In a first embodiment, the means to couple the external shaft to the hub is accomplished as follows. An upper end portion of the hub shaft has a cylindrical, upper recess that extends downward along the turbine shaft axis from the upper end of the hub shaft to a bottom end of the lower recess of the hub shaft. 
     The upper recess is defined by an upper recess wall that is dimensioned to receive in surrounding engagement a lower end portion of the external shaft. The upper recess wall has a pair of grooved pathways or keyways disposed at diametrically opposite locations on the recess wall. Each pathway or keyway includes, sequentially, a first leg that extends from the upper end of the hub shaft toward the bottom end of the recess. A second leg is included and extends through a circumferential arc normal to the turbine shaft axis. Also included is a third leg extending in reverse and part way back toward the upper end of the hub shaft  70 , thereby forming a blind end of the pathway. 
     A pair of oppositely-disposed, oppositely-directed or extending ears or keys are attached to, and extend away from the lower end portion of the external shaft, which ears or keys are shaped and dimensioned to be received in sliding engagement within the grooved pathways or keyways. A disk-shaped buffer plate is disposed within the upper recess intermediate and between the bottom end and the grooved pathways thereof. 
     The buffer plate is dimensioned for sliding engagement with an inner surface of the upper recess wall and along the turbine shaft axis. A spring is disposed between and intermediate to the bottom wall of the upper recess and the buffer plate. The spring urges the buffer plate away from the bottom end of the recess and toward the grooved pathways. 
     To install the external wind turbine on a parked, all-electric, or hybrid electric vehicle, it will be used with the internal wind turbine remaining in place mounted on the roof exterior and with the lid lowered and locked. A lower end of the external shaft of the external wind turbine is inserted down through the opening of the lid, and aligned to be coaxial with the internal wind turbine shaft axis. During installation, the ears or keys of the external wind turbine are aligned with the first legs of the grooves or keyways. 
     The external wind turbine shaft is pressed downward against the buffer plate as the keys or ears slide down through the first legs of the keyways or grooves, thereby compressing the spring. The external shaft is then partially rotated about the turbine shaft axis to twist and move the ears into and through the second legs of the grooves. Next, the external shaft is partially retracted so that the ears or keys slide up the third legs, to lodge the keys or ears within the blind ends of the grooves or keyways. To dismount the external wind turbine from the vehicle, this process is reversed. 
     In a second, alternative embodiment of the invention, the coupling of the external wind turbine shaft to the hub of the internal wind turbine is accomplished as follows. An upper end portion of the hub shaft of the internal wind turbine is formed with an upper recess extending downward along the internal wind turbine shaft axis, between (10 the upper end of the hub shaft and (2) a bottom end of the recess. The upper recess is defined by the upper recess wall, which is shaped and dimensioned so that can receive and surroundingly engage the lower end portion of the external shaft. 
     One or more ball-and-spring assemblies are attached to an inner surface of the recess within an alcove thereof. Each ball-and-spring assembly comprises a spring having a first end attached to the upper recess wall and a second, opposite end to which is attached a ball, such that the ball is movable between an extended, recess-occluding position and a retracted, non-occluding position within the alcove. 
     The lower end portion of the external shaft has at least one beveled indent that is shaped and dimensioned to receive in sliding engagement the ball of the ball-and-spring assembly, thereby causing, as the external shaft is moved into the upper recess, the following sequence of events: sliding engagement with the balls, progressive compression of the springs, retraction of the balls into the respective alcoves, and then capture of the balls within the beveled indent of the external shaft. Accordingly, downward movement of a lower end of the external shaft along the turbine shaft axis will seat the external shaft for co-rotation with the hub. Conversely, a forceful yank upwards on the external shaft de-couples the shaft from the upper recess to enable removal of the external wind turbine from the vehicle when not needed, and for storage. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front, perspective view of an electric vehicle such as an all-electric motor vehicle equipped with a roof mounted wind turbine system configured for charging the electric storage battery of the vehicle from a wind stream moving about the roof while the vehicle is in motion and/or when still at times when wind blows; 
         FIG. 2  a top, perspective view of the wind turbine system of  FIG. 1 , with a lid removed from the system for illustration purposes; 
         FIG. 3  is a front, perspective view of the wind turbine system of  FIG. 1  showing the lid being hinged about the system, and being positioned partially raised to showblades of a turbine blade assembly; 
         FIG. 4  is a rear, elevational view of the system of  FIG. 1  with the lid in closed position; 
         FIG. 5  is a front, perspective view thereof of the system of preceding figures, with an external wind turbine mounted to the vehicle for charging an electric storage battery of the system while the vehicle is parked; 
         FIG. 6  is an enlarged, exploded, perspective side view of the system of the preceding figures, showing an internal wind turbine assembly of the system; 
         FIG. 7  is an exploded, perspective side view of the system of preceding figures, and illustrating a turbine hub assembly and an upper end portion of an electric generator shaft having a lower splined adaptor; 
         FIG. 8  is an enlarged, side elevational view of the hub assembly of  FIG. 7 , showing a hub shaft, which extends along the axis A-A ( FIG. 7 ) of the hub and which protrudes above the hub. Also depicted are the turbine blades installed into radially-directed collars; 
         FIG. 9  is a vertical cross-section view taken along line  9 - 9  of  FIG. 8 , with various structure removed for illustration purposes; 
         FIG. 10  is a perspective, side view of a single turbine blade of  FIGS. 7, 8, and 9  with various structure removed for clarity of illustration, showing the blade inserted into the collar, and having a pair of weights attached to an upstream, concave side of a blade at the tip end thereof; 
         FIG. 11  is an enlarged, perspective, side view of the hub shaft of  FIGS. 6, 7, 8 , and  9 , wherein an upper end portion of the hub shaft has a cylindrical, upper recess dimensioned to receive a lower end portion of the external shaft of the external wind turbine of  FIG. 5  in position prior to installation; 
         FIG. 12  is an enlarged, vertical, cross-sectional view of the lower end portion of the external turbine shaft of  FIGS. 5 and 11  after installation, and showing an opening in the lid; 
         FIG. 13  is an enlarged, perspective, side view of an alternative hub shaft of  FIGS. 5, 11 , &amp;  12  show in position prior to installation; 
         FIG. 14  is an enlarged, cross-section of the assembly of  FIG. 13  showing the alternative hub shaft after installation; and 
         FIG. 15  is an enlarged, top plan view with various structure removed for clarity, and showing the external wind turbine of  FIGS. 5, 11, 12, 13, 14  during operation. 
     
    
    
     DETAILED DESCRIPTION 
     Referring now to  FIGS. 1, 2, 3, and 4 , the internal wind turbine  10  of the present invention is shown mounted to the roof  14  of an all-electric or hybrid motor vehicle  12 . The motor vehicle depicted is a 2-door sedan, but the invention can be installed on the roof of other types of motor vehicles, such as hybrid and all-electric 4-door sedans, roadsters, vans, pickup trucks, utility vehicles, and other types of vehicles. A wind turbine is contemplated that is installed either as original equipment by the vehicle manufacturer, or as an after-market addition, or as a combination thereof. 
     Although not depicted in the drawings, it will be understood that the vehicle  12  is equipped with one or more electric storage batteries that provide electric power to various components of the vehicle, including one or more drive motors that are in driving engagement with the wheels  18  of the vehicle when the vehicle is being driven. 
     Prior to installation of the internal wind turbine  10  on the roof  14  of the vehicle  12 , a vertical through-hole  16  is formed or drilled through the roof  14  as may be seen in  FIGS. 6, 12, and 14 . The internal wind turbine  10  is enclosed in a housing  20 , which includes a bottom panel  22  extending longitudinally from a front end  22 F to an opposite, rear end  22 R, and which also extends laterally between a first side  26  and an opposite, second side  28 . 
     For ease of installation, and improved operational efficiency and aesthetic appearance, and specifically to minimize wind resistance and noise during operation when the vehicle is being driven, the bottom panel  22  is preferably dimensioned and contoured to closely overlie an exterior surface of at least a portion of the vehicle roof  14  that includes the through-hole  16 . More preferably, the bottom panel  22  is formed to be adjustably conformal to the vehicle roof  14  to minimize any leading edge gaps between the bottom panel  22  and the roof  14 . For purposes of example, the gap between the bottom panel  22  and the leading edge and exterior surface of the roof  14  preferably should be kept to less than 5 mm. 
     With reference also now specifically to  FIG. 2 , the bottom panel  22  is depicted being formed with a-centrally disposed area of generally flat, upper surface  30 , which defines a vertically-directed, shaft opening  32  extending through the bottom panel  22  to an opposite, lower surface of the bottom panel  22 . A front end  22   f  of the bottom panel  22  defines an air inlet opening  34 , which is positioned to enable air to enter the internal wind turbine  10  while the vehicle  12  is in forward motion. 
     The bottom panel  22  also includes an air outlet opening  36  defined by a rear end  22 R of the bottom panel  22 , which enables air to exit the internal wind turbine  10 . An air flow corridor  38  is formed about the bottom panel  22  and extends between and joins the air inlet opening  34  with the air outlet opening  36 . 
       FIG. 2  shows the air flow  38  corridor further including an entryway portion  38 E in communication with the air inlet opening  34 , a discharge portion  38 D in communication with the air outlet opening  36 , and a central portion  38 C in communication with the entryway  38 E and discharge  38 D portions. The entryway portion  38 E is preferably contoured to channel or conduct air flowing into the inlet opening  34  toward the second side  28  of the bottom panel  22 . 
     The central portion  38 C is also contoured to conduct air from the entryway portion  38 E substantially rotationally around the shaft opening  32 . The central portion  38 C is also defined by first and second, upstanding, semicylindrical, interior walls that are laterally and generally symmetrically spaced apart on opposite sides of the turbine shaft axis A-A. 
     Although the term “semicylindrical” generally refers to a bisected half of a cylinder, here it is intended to not be so limited and to instead describe an arcuate form that can be somewhat less than a full, 180° semicircular or semicylindrical arc of the noted bisected half of a cylinder. For purposes of example, the cross section of the described contoured central portion  38 C contemplated a cross section having an arcuate form defining an arc anywhere in the range of about 120° to about 180°. The discharge portion  38 D is similarly contoured to conduct air from the central portion  38 C to the air outlet opening  36 . 
     Accordingly, with the vehicle  12  in forward motion, air enters the internal wind turbine  10  through the air flow corridor  38  and transfers its kinetic energy to rotate a turbine blade assembly  40  about the turbine shaft axis A-A ( FIGS. 6 &amp; 7 ) in a counterclockwise direction as the corridor  38  is depicted in  FIG. 2 . The internal wind turbine  10  may be further adapted wherein the air flow corridor  38  further includes a tongue  38 T ( FIG. 2 ) that extends laterally from a first pivot mount  81  ( FIG. 6 ) partially across and above the front end  22 F of the bottom panel  22 , thereby further defining the air inlet opening  34 . 
     With this arrangement, the tongue  38 T deflects the oncoming flow of air away from the first side  26  and toward the second side  28  of the bottom panel  22 . This in turn further improves the directional control of the air flowing through the internal wind turbine.  10 , which is intended to improve the energy transfer from the moving air to the turbine blade assembly  40 . 
     Referring now also to  FIGS. 6-12 , the configuration of the turbine blade assembly  40  can be understood to be disposed within the central portion  38 C of the air flow corridor  38 . The turbine blade assembly  40  includes a hub  42  that rotates about turbine shaft axis A-A, and which extends axially along the axis A-A between a first, lower end  42 L and a second, upper end  42 U thereof. 
     A plurality of turbine blades  44  is distributed about the periphery of the hub  42  and extend radially away from the hub  42  generally normal to the turbine shaft axis A-A. The hub  42  has a collar  41  for each blade  44 , disposed within an opening in the hub  42 , which collar  41  may be welded or press fit within the hub opening. 
     A first end of each blade  44  is attached by threaded fasteners  45  (e.g., hex-head bolts) to a collar  41  and has an opposite, tip end  46 . Preferably, each blade tip  46  is weighted as, for example as shown in  FIG. 10 , by one or two weights, which can be beads of metal  47  welded to an upstream, concave side of the blade tip. Preferably, each blade tip includes weights amounting to approximately at least 10% the weight of the entire blade  44 , the weight being selected to optimize the rotational balance and/or the angular momentum of the turbine blade assembly  40 . A damaged blade  44  may be removed for replacement by loosening its threaded fasteners  45  and removing the blade from its collar  41 . 
     Referring now to  FIG. 6 , the internal wind turbine  10  if further depicted to include an electric generator  48 , an attachment assembly  50  for attaching the electric generator  48  to an inside surface of the roof  14  of the vehicle  12 , and means  52  ( FIGS. 6 &amp; 7 , described in more detail below) for coupling a shaft  54  of the electric generator  48  to the hub  42 . 
     The means  50  for attaching the electric generator  48  to the inside surface of the roof  14  can be any of various means known to persons of ordinary skill in the art of installation of motor vehicle electrical components, such as the pair of brackets  56  and the threaded fasteners  58  depicted in  FIG. 6 . To minimize reduction of headroom space inside the passenger compartment of the vehicle  12 , the electric generator  48  should be compact and have a narrow side profile. Alternatively, the electric generator  48  may be carried exterior to the vehicle (not shown) and within the enclosure of internal wind turbine  10 . This latter arrangement eliminates the need for creating a through bore in the roof  14 . 
     The means  52  ( FIGS. 6 &amp; 7 ) for coupling the shaft  54  of the electric generator.  48  to the hub  42  are preferably attached to the shaft  54  to rotate about the turbine shaft axis A-A. The means  52  includes, as illustrated in  FIG. 7 , an adaptor  60  that is attachable to the generator shaft  54  by, for example, set screws  62  that screw into threaded apertures in the adaptor  60 . 
     The adaptor  60  includes a plurality of radially-directed splines or vanes  60 S circumferentially spaced apart about the adaptor. A throughbore  60 B is included to have a diameter dimensioned to receive the generator shaft  54 . Although the adaptor  60  depicted in  FIG. 7  has four splines  60 S, the number of splines may also vary from one to 12 or as otherwise needed. The hub  42  has an axial throughbore  42 B that extends from the lower end  42 L to the upper end  42 U thereof. 
     A hub shaft  70  having an external diameter somewhat less than the internal diameter of the throughbore  42 B is slidably insertable into and out of the throughbore. Optionally, when fully inserted into the throughbore  42 B of the hub  42 , the hub shaft  70  may have an upper end portion  74  that protrudes above the upper end  42 U of the hub  42 , as depicted in  FIG. 6 . This protrusion is limited to prevent interference with lowering the lid  80  to a fully closed and locked position. 
     A lower end portion of the hub shaft  70  includes a lower recess  72  (shown as hidden lines with phantom outline in  FIG. 7 ), which is shaped and dimensioned to receive in mating engagement the splines  60 S of the adaptor  60 . When the splines  60 S of the adaptor  60  are inserted within the lower recess  72  of the hub shaft  70 , the generator shaft  54  is coupled for co-rotation with the hub shaft  70 . 
     A pin  76  is insertable through a horizontal aperture  78  in the hub shaft  70  as well as through a co-aligned aperture  73  in hub  42  near the upper end  42 U of the hub  42 . So long as the pin  76  is so inserted through both the hub  42  and the hub shaft  70 , the generator shaft  54 , adaptor  60 , hub shaft  70  and hub  42  are mechanically coupled and will rotate as one about the turbine shaft axis A-A. 
     Moreover, in the event the vehicle  12  is jostled traversing uneven ground, the pin  76  prevents relative vertical movement between the hub  42  and the hub shaft  70 . By raising or removing the lid  80  and withdrawing the pin  76  from the hub  42  and hub shaft  70 , the hub  42  and attached blades  44  can be lifted up and away from the adaptor  60  and hub shaft  70 . This configuration enables replacement of a damaged blade  44  and/or cleaning the housing  20  of accumulated dirt and debris. 
     To minimize the friction of rotation of the turbine blade assembly  40  and to support the axial load thereof, a concentric pair of ball bearing races  33  containing a plurality of ball bearings (not shown) are interposed between the lower end  42 L of the hub  42  and the upper surface  30  of the bottom plate  22 . Being centered on the turbine shaft axis A-A, the ball bearing races  33  are attached to the upper surface  30 . The lower end  42 L of the hub  42  rests on the ball bearings  33 , as shown in  FIG. 6 . The internal wind turbine  10  further includes a lid  80  that extends longitudinally from a front end  80 F to an opposite rear end  80 R. The lid  80  is shaped and dimensioned to cover the entirety of the housing  20 . The housing  20  has a pair of laterally spaced-apart, upstanding, apertured, pivot mounts  81  attached to the bottom panel  22 , at or near a front end  22 F of the panel. A front end  80 F of the lid  80  has a laterally-directed, pin-receiving aperture  85 , which is pivotally attached to the pivot mounts  81  by a pair of pivot pins  83  that insert into the apertures. This enables the lid to pivot between a lowered, housing-covering position ( FIG. 1 ) and a raised, open position ( FIG. 3 ). 
     To facilitate repair and maintenance of the internal wind turbine  10 , the pivot pins  83  can be withdrawn froth the pivot mounts  81 , which permits removing the lid  80  entirely from the housing  20 . The lid  80  has an opening  82  aligned with the turbine shaft axis A-A when the lid is in the lowered position. In the lowered position, the lid  80 , in combination with the corridor  38 , bottom panel  22  and seal means  90 , forms a closed compartment surrounding the turbine blade assembly  40 . 
     Referring to  FIG. 6 , the seal means  90  for sealing the housing  20  against moisture and air leaks includes hub grommet  92  such as a ring washer. The grommet  92  is joined to an upstanding, hollow, cylindrical, neck or tube that extends up through the opening  82  in the lid  80 . The neck portion of the hub grommet  92  extends above the upper surface of the lid  80  by, for example, 3 to 10 mm. A removable cap  96  is included and has a downward-directed hollow, cylindrical neck or tube mounts on that upper, extended neck portion of the hub grommet  92 . 
     Preferably, the seal means  90  further includes an annular washer  97  that also mounts on the neck portion of the hub grommet  92  between the upper surface of the lid  80  and the cap  96 . The seal means  90  will ordinarily remain in place attached to the lid  80  while the lid is being pivoted up and down between its lowered and raised positions. 
     When the vehicle  12  is parked with the lid in lowered position, and it is desired to use wind energy to charge the electric storage battery, the cap  96  is removed and an external shaft  202  of an external, second wind turbine  200  is inserted through the lid opening  82  and hub grommet  92 . The lid opening  82  and the hub grommet  92  are dimensioned to receive the external shaft  202 . The hub grommet  92 , cap  96  and annular washer  97  may preferably be formed from butyl rubber, pliable silicone materials, or any other suitably flexible material. 
     The internal wind turbine  10  also has lid locking means, denoted generally by the numeral  100 , comprising a laterally spaced apart pair of upper half clasps  102  that attach by hinges to the rear end  80 R of the lid  80  and a mating, laterally spaced apart pair of half clasps  104  that attach to a rear portion of the vehicle  12  by threaded fasteners  106 , for example, to a rear portion  14 R of the roof  14  thereof. Any of a variety of kinds of mating pairs of half clasps can be used for this purpose, for example, the mating pairs of half clasps on steamer trunks as well the mating pairs of half clasps on mechanics&#39; tool boxes. 
     For converting ambient wind energy into electrical current to charge the electric storage battery of a hybrid and/or all-electric vehicle  12  while the vehicle is parked, the invention further includes an external, second wind turbine  200  ( FIGS. 5 &amp; 15 ). The external, second wind turbine  200  may be stored in the trunk  13  or other secure location within the vehicle  12  until needed. 
     As may be seen in  FIGS. 5 and 15 , the external wind turbine  200  includes an external shaft  202  that extends from an upper end  202 U to an opposite, lower end  202 L along an external shaft rotation axis. The external wind turbine  200  further includes a plurality of radially-directed arms  204  circumferentially spaced apart around the upper end  202 U of the external shaft  202 . Each arm  204  has an inner end  2041  attached to the external shaft  202  and an opposite, outer end  204 J. For catching ambient wind currents, a cup  206  is attached to an outer end  204 J of each arm  204 . 
     Each cup  206  has a concave inner surface  208  (shown in  FIG. 5 , and as dashed lines in  FIG. 15 ) and a convex outer surface  210  that meet at the opening  212  of the cup. The opening  212  of each cup  206  is directed essentially along the tangent to the rotational path (arrows,  232 ) of the cups about the external shaft axis, and all the cups are oriented in the same rotational sense about the external shaft axis, as illustrated, for example, in  FIGS. 5 &amp; 15 . 
     The number of arms and cups is variable, but three of each, which may be spaced apart at 120-degree intervals about the external shaft axis is a preferred number. Thus, the external wind turbine  200  resembles a cup anemometer in appearance and mechanical function. Cups  206  are used in the external wind turbine instead of turbine blades as a better way to harness the energy in ambient, variable, low velocity winds while the vehicle  12  is parked. 
     The external wind turbine  200  includes means to couple a lower end portion  202 L of the external shaft  202  to the hub  42  while maintaining the external shaft in coaxial alignment with the turbine shaft axis A-A. To that end, an upper end portion  70 U of the hub shaft  70  has a recess wall  230 W that defines a cylindrical recess  230 , which extends downward along the turbine shaft axis A-A from the upper end of the hub shaft to a bottom end  230 B of the recess. 
     The recess  230  is shaped and dimensioned to receive the cylindrical, lower end portion  202 L of the external shaft  202  when the shaft is inserted through the opening  82  of the lid  80 . In a first embodiment of the invention, the recess wall  230 W has a pair of grooved pathways  270  disposed at diametrically opposite locations on the recess wall. 
     As depicted in  FIGS. 11 and 12 , each pathway  270  includes a first leg  270 A that extends from the upper end of the hub shaft  70  toward the bottom end  230 B of the recess  230 . A second leg  270 B is also included that extends through a circumferential arc normal to the turbine shaft axis A-A. Next, an included third leg  270 C extends reversely part way back toward the upper end of the hub shaft  70 , thereby forming a blind end of the pathway  270 . 
     Attached to the lower end portion  202 L of the external shaft  202  are a pair of oppositely-disposed, oppositely-directed ears  220 . The ears  220  are shaped and dimensioned to be received in sliding engagement within the grooved pathways  270  when the lower end portion  202 L of the external shaft is inserted into the recess  230 . 
     Preferably, a lower end portion  202 L of the external shaft  202  is coupled to the hub  42  and further includes a disk-shaped, buffer plate  260  disposed near the bottom end  230 B of the recess  230 . The diameter of the buffer plate  260  is slightly less than the internal diameter of the recess  230  so that the buffer plate  260  can slide axially up and down along the recess wall  230 W. A spring  262  (e.g., a coil spring) urges the buffer plate  260  axially upwards towards the pathways  270 , and is positioned between the buffer plate  260  and the recess bottom  230 B. 
     To couple the external shaft  202  to the hub shaft  70 , the lower end portion  202 L of the external shaft is inserted through the opening  82  of lowered lid  80 . Next, the ears  220  are aligned with the first legs  270 A of the pathways  270 . The shaft  202  is then pressed down against the buffer plate  260  as the ears slide down along the first legs  270 A (arrow  240 A), thereby compressing the spring  262 . 
     The external shaft  202  is then rotated about the turbine shaft axis A-A to slide the ears  220  through the circumferential legs  270 B (arrow  240 B). Lastly, the external shaft  202  is retracted axially to permit the ears  220  to slide along legs  270 C (arrow  240 C) and lodge in the blind ends of the pathways  270 . The spring  262  helps to keep the ears  220  firmly within the blind ends of the pathways  270 . 
     For this to work properly, the distance H between the ears  220  and the lower end of the external shaft  202  needs to be about equal to the distance between the buffer plate  260  and the blind ends of the pathways  270  when the external shaft is coupled to the hub shaft. In other words, when the spring  262  is at least partially decompressed to urge the buffer plate,  260  against the ears  220 , which urges and lodges the ears  220  into the blind ends of the pathways  270 . To uncouple the external shaft  202  from the hub shaft  70 , this process is simply reversed. 
     In a second, alternative arrangement illustrated in  FIGS. 13 and 14 , the hub shaft  70  likewise has an axially-directed, cylindrical recess  230  that extends from the upper end of the hub shaft to a bottom end  2308  of the recess. The recess is dimensioned to receive in surrounding engagement a lower end portion  202 L of the external shaft  202 . 
     As depicted in  FIGS. 13 and 14 , an oppositely-disposed pair of ball-and-spring assemblies, denoted generally by the numeral  250 , is attached to the recess wall  230 W. Each such assembly  250  comprises a spring  254  having a first end attached to an alcove  256  in the recess wall  230 W and an opposite end attached to a ball  252 . For each assembly  250 , when its spring  254  is uncompressed, its ball  252  extends at least part way out of the alcove  256  and partially occludes the recess  230 . 
     A lower end portion  202 L of the external shaft  202  has a pair of oppositely-disposed, notched, indents  258 . Each indent  258  comprises an upper, inwardly beveled edge surface that is joined to a lower, outwardly beveled edge surface. The distance H′ between the bottom  202 B of the external shaft  202  and the indents  258  corresponds to the distance H′ between the recess bottom  230 B and, the ball-and-spring assemblies  250 . 
     Accordingly, to couple the external shaft  202  to the hub shaft  70 , with the vehicle  12  parked and the lid  80  in lowered position, the cap  96  is removed and the lower end portion  202 L of the external shaft is passed through the lid opening  82  and into the hub shaft recess  230 . Initially, downward movement of the external shaft  202  forces the balls  252  into the alcoves  256  and the springs  254  are compressed; but, upon arrival of the indents  258  at the alcoves  256 , the balls, under the urging of the springs  254 , move into the indents. 
     Thus, to operate properly, the alcoves  256  need to be large enough to accommodate both the balls  252  and the springs  254 . To uncouple the external shaft  202  from the hub shaft  70 , the external shaft is grasped and yanked upward, thereby sliding the lower beveled surfaces of the indents  258  past the balls  252 , forcing the balls back into the alcoves until the external shaft has been fully raised above them, after which the balls once again extend from the alcoves out into the recess. Although only a single pair of indents  258  and a single pair of ball-and-spring-assemblies  250  have been illustrated and described, additional pairs of each for coupling the external shaft  202  to the hub shaft  70  are within the scope and intent of the present invention. 
     Thus, it should be evident that a system for harnessing wind energy to charge an electric storage battery of any type of vehicle, including an all-electric motor vehicle has been shown and described in sufficient detail to enable one of ordinary-skill in the art to practice the invention. Although not illustrated and described above, it will be understood that practicing the invention requires routing electrical cables from electrical output terminals of the generator  48  through the vehicle  12  to its electrical storage battery and charging system. 
     Since various modifications in detail, materials, arrangements of parts, and equivalents thereof, are within the spirit of the invention herein disclosed and described, the scope of the invention should be limited solely by the scope of the appended patent claims.