Abstract:
A solar-powered vehicle with regenerative and mechanical braking includes a chassis or frame, a seat mounted to the frame, a rear axle rotatably supported on the frame, spaced apart left and right rear wheels mounted on the rear axle, and at least one front wheel mounted on the frame. The vehicle includes a selectively engageable regenerative braking system and a selectively engageable mechanical braking system. A lever for engaging the braking systems has three positions, wherein at a first position a reed switch on the lever engages a magnetic source, disabling the regenerative braking system. At a second position, the reed switch disengages the magnetic source, enabling the regenerative braking system. At a third position of the lever, the mechanical braking system is engaged.

Description:
RELATED APPLICATIONS 
       [0001]    Not Applicable. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates generally to a solar-powered vehicle, and more specifically to a solar-powered vehicle with multi-stage regenerative and mechanical braking. 
         [0004]    2. Background 
         [0005]    Transitioning away from petroleum-based energy sources has become a primary focus of research and development in the energy industry, as well as in industries that rely on petroleum fuels to power their products. Investment in alternative-fuel vehicles, for example, has skyrocketed in recent years. 
         [0006]    In 2010 there were an estimated one billion vehicles in the world. The vast majority of these vehicles were gasoline-powered. Heavy reliance on petroleum-based fuels like gasoline presents a number of problems, and the major economies of the world are increasingly looking for ways to deal with, or prevent, these problems. Fossil fuel use has been identified as one of the largest contributors to air pollution around the globe. This pollution stems primarily from combustion of the fossil fuels, resulting in carbon monoxide, nitrogen oxide, hydrocarbon, and particulate emissions into the atmosphere. Carbon monoxide is highly toxic to air-breathing animals because of its interference with the ability of the blood to transport oxygen. Even small amounts of carbon monoxide can cause damage to cardiovascular tissue. Nitrogen oxides irritate the lungs and lead to acute respiratory disease, particularly in children. In addition to these direct harms, fossil fuel combustion is thought to be a major contributor to global climate change, resulting in innumerable indirect harms to humans and other species as temperatures around the globe increase. Use of petroleum fuels such as gasoline also results in evaporative emissions, which release fuel vapors into the atmosphere without combustion of the fuel. 
         [0007]    Researchers looking into alternative fuel vehicles have explored a variety of options for moving vehicles away from a reliance on fossil fuels. These areas of research include battery/electric-powered vehicles, solar-powered vehicles, and vehicles powered by alternative fuels such as dimethyl ether (DME), ammonia, ethanol, biodiesel, biogas, hydrogen, and others. Each of these possible alternatives presents a variety of challenges and difficulties that must be overcome. 
         [0008]    Solar-powered vehicles are known in the art. Such vehicles typically employ photovoltaic cells to convert energy from the sun into electric energy. Such vehicles have been largely impractical for day-to-day transportation. There are a number of factors that account for this impracticality. For example, power from a solar array is limited by the size of the photovoltaic array and the surface area of the photovoltaic array that is exposed to sunlight. This is, in turn, limited by the size of the vehicle itself. A larger vehicle, having more available space for photovoltaic cells, also requires more energy to move. Further, while batteries can be employed to store energy from the photovoltaic cells, the battery also adds to the overall weight of the vehicle. Photovoltaic panels are also heavy. In order to be useful, the energy supplied by a photovoltaic panel must be sufficient to offset the increased weight of the vehicle as a result of the panel. 
         [0009]    Electric vehicles, such as solar-powered vehicles, can use regenerative braking to recapture, in useful form, some of the kinetic energy of the vehicle while slowing the vehicle. Regenerative braking is known in the art, and the energy obtained from such braking can be stored and used to provide power to the vehicle when necessary. Regenerative braking alone, however, is not sufficient to meet the braking needs of a vehicle. More traditional mechanical braking, such as dissipative braking, is also desired so that the operator of a vehicle can stop rapidly if required. Dissipative braking converts the kinetic energy of the vehicle into dissipative energy. Common examples of dissipative braking include disk brakes and drum brakes. 
         [0010]    Control of two separate braking systems can provide a complex problem for the operator of a vehicle. In many vehicles, such as cars, computer systems control the interplay between the two braking systems, thereby reducing the burden on the operator of the vehicle. In simpler vehicles, where computerized control of braking systems is not desirable, control of the braking systems is left to the operator, who may have to rely on two separate mechanisms to control the individual braking systems. This adds a layer of complexity to the user&#39;s operation of the vehicle, and increases the risk of error on the part of the user. 
         [0011]    What is needed, then, is a solar-powered vehicle that overcomes limitations in the art, providing a practical vehicle for day-to-day transportation. Also needed is such a vehicle wherein the regenerative and dissipative braking systems are easily controlled by the operator of the vehicle. 
       SUMMARY OF THE INVENTION 
       [0012]    The present invention provides a solar-powered vehicle with regenerative and mechanical braking. In one embodiment of the invention, the vehicle includes a chassis or frame, at least one seat mounted to the frame, a rear axle rotatably supported on the frame, spaced apart left and right rear wheels mounted on the rear axle, and at least one front wheel mounted on the frame. A first chain drive assembly is coupled to the left rear wheel and a first pedal is associated with the first chain drive assembly. A second chain drive assembly is coupled to the second right rear wheel and a second pedal is associated with the second chain drive assembly. The vehicle includes a selectively engageable regenerative braking system and a selectively engageable mechanical braking system. A lever for engaging the braking systems has three positions, wherein at a first position a reed switch on the lever engages a magnetic source, disabling the regenerative braking system. At a second position, the reed switch disengages the magnetic source, enabling the regenerative braking system. At a third position of the lever, the mechanical braking system is engaged. 
         [0013]    Another embodiment of the present invention further includes at least one photovoltaic cell supported on the frame. A motor in electrical communication with the photovoltaic cell is operatively coupled to at least one wheel of the vehicle. 
         [0014]    In another embodiment of the present invention, at least one of the chain drive assemblies is a multi-geared chain drive. A gear selector is provided for adjusting the ration of the chain drive. 
         [0015]    Another embodiment of the present invention provides a vehicle having regenerative and mechanical braking. The vehicle includes a braking controls for selectively engaging the braking systems, the braking control having a first position, a second position, and a third position. At the first position, neither of the mechanical or regenerative braking systems is engaged. At the second position, the regenerative braking system is engaged. At the third position, the mechanical braking system is engaged. A battery is in electrical communication with the regenerative braking system. At least one photovoltaic cell is in communication with the battery. The photovoltaic cell and the regenerative braking system are operable to charge the battery. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]      FIG. 1  is a front perspective view of one embodiment of a vehicle of the present invention. 
           [0017]      FIG. 2  is a driver&#39;s side perspective view of one embodiment of a vehicle of the present invention. 
           [0018]      FIG. 3  is a perspective view of one embodiment of a selectively engageable braking control of the present invention, the braking control shown in a first position. 
           [0019]      FIG. 4  is a perspective view of one embodiment of a selectively engageable braking control of the present invention, the braking control shown in a second position. 
           [0020]      FIG. 5  is a perspective view of one embodiment of a selectively engageable braking control of the present invention, the braking control shown in a third position. 
           [0021]      FIG. 6  is a perspective view of a rear portion of one embodiment of a vehicle of the present invention, the figure showing a placement of a battery associated with the vehicle. 
           [0022]      FIG. 7  is a passenger side perspective view of one embodiment of a vehicle of the present invention. 
           [0023]      FIG. 8  is a wiring diagram showing exemplary wiring of one embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0024]    Turning now to the drawings, wherein like numeral indicate like parts, the numeral  10  refers generally to one embodiment of vehicle  10  of the present invention. The embodiment of vehicle  10  shown in the drawings includes, generally, a frame or chassis  12 , the chassis  12  having a pair of front stub axles  14  and a pair of rear stub axles  16  associated therewith. Front stub axles  14  and rear stub axles  16  are, in turn, each associated with a wheel  18  that rotates along with the rotational movement of a respective axle. Vehicle  10  further includes first chain drive assembly  26  and second chain drive assembly  28 , first chain drive assembly  26  being powered by first pedals  22  and second pedals  24 , and second chain drive assembly being powered by third pedals  52  and fourth pedals  54 . 
         [0025]    Other components of the present invention are also shown in  FIG. 1 . For example, steering wheel  20  is shown connected to steering shaft  56 . It is to be understood that a variety of mechanisms for steering a vehicle are known to those of skill in the art, and that any suitable mechanism may be provided for steering the present device.  FIG. 1  also shows a brake cable  44  for actuation of a mechanical, or dissipative, braking system of the present invention, described in greater detail below. 
         [0026]    Steering wheel  20  is also shown in  FIG. 2 , steering wheel  20  being associated with steering shaft  56  for steering of vehicle  10 . Also shown is canopy  36 , supported above vehicle  10  by a plurality of supports  62 . Canopy  36  provides a surface onto which photovoltaic panels  38  may be disposed, thereby providing sufficient space for generation of electrical energy from solar energy. The device shown in  FIGS. 1 and 2  is shown from a passenger-side perspective in  FIG. 7 . 
         [0027]    Chain Drive Assembly 
         [0028]    Use of a chain drive in operator-powered vehicles is well known in the art. Chain drives may be provided with or without a gear system. The use of gears allows the user of the vehicle to change the ratio of revolutions of the pedals to revolution of the tires, allowing the user to adapt the chain drive to specific situations as necessary or desired. When climbing hills, for example, the gear mechanism may be used to allow many pedal rotations to a single wheel rotation. When traveling downhill, the opposite may be true, with the gear setting allowing many rotations of the wheel for a single rotation of the pedals. 
         [0029]    Many pedal-powered vehicles use external “derailleur” gearing. The operator may use a lever, twist grip, or combination of the two to change the tension in the chain on the chain drive. This change in tension causes the chain to move (or derail) from one sprocket to another, thereby changing the gear ration of the vehicle. This type of gearing generally requires that the operator of the vehicle be pedaling when gears are shifted. Other types of gearing mechanisms are also known in the art, some of which are internal or are a combination of internal and external gearing. It is contemplated that any suitable gearing mechanism may be used in conjunction with the present invention. 
         [0030]      FIG. 2  is a driver&#39;s side perspective view of one embodiment of a vehicle  10  of the present invention. First chain drive assembly  26  is visible, as is second chain drive assembly  28 . Two sets of pedals, first pedals  22  and second pedals  24 , are shown in association with first chain drive assembly  26 , such that when either of first pedals  22  or second pedals  24 , or both, is operated, first chain drive assembly  26  is engaged and the rear driver&#39;s side wheel  18  of vehicle  10  is caused to rotate. This rotational movement of the wheel  18 , of course, causes a corresponding movement of vehicle  10 . Chain drive assemblies are known in the art and are available in a variety of forms, differing in gear speeds available to the operator, and the like. It is contemplated that any suitable chain drive assembly may be used in conjunction with the present vehicle  10 . 
         [0031]      FIG. 2  also depicts a twist grip  66  used for changing the gear ratio of the present vehicle  10 . As noted above, the gearing system of the vehicle  10  may be any suitable gearing system. Although a twist grip  66  is shown in conjunction with the embodiment of vehicle  10  shown in the drawings, it is contemplated that a lever or other suitable mechanism for changing gears may be utilized.  FIG. 2  depicts vehicle  10  as seen from the driver&#39;s side, and twist grip  66  controls the gearing of the driver&#39;s side chain drive. It is contemplated that a twist grip or other gear control mechanism is likewise used to control gearing on the driver&#39;s side. 
         [0032]    Braking 
         [0033]      FIG. 3  provides a close perspective view of one embodiment of a selectively engageable braking control  32  of the present invention, the braking control being shown with lever  64  in a first position. In the embodiment shown in the figure, selectively engageable braking control  32  includes a lever  64 , the lever having a magnetic source  40  affixed thereto. Selectively engageable braking control  32  also preferably includes a reed switch  42  disposed such that lever  64  can be pivoted to bring magnetic source  40  into contact with reed switch  42  when lever  64  is in a first position as shown in the Figure. As described below, lever  64  can also be pivoted to disengage magnetic source  40  from reed switch  42 . 
         [0034]      FIG. 4  shows the selectively engageable braking control  32  of  FIG. 3 , where lever  64  is in a second position. In the second position, the magnetic source  40  is disengaged from the reed switch  32 , but braking control  32  is not pulled back sufficiently to engage the mechanical braking system. This disengagement of the magnetic source  40  from reed switch  42  results in activation of the regenerative braking system of vehicle  10 . The regenerative braking system slows vehicle  10  as the kinetic energy of vehicle  10  is converted to electrical energy. The method by which regenerative braking systems operate is known in the art. In some instances, use of the regenerative braking system may be sufficient to meet the needs of the vehicle operator. In other situations, the operator may desire a more rapid or complete slowing, in which case the selectively engageable braking control  32  can be utilized to engage the dissipative braking system of vehicle  10 . 
         [0035]      FIG. 5  shows engagement of the dissipative braking system of vehicle  10  using selectively engageable braking control  32 . When braking control  32  is moved to a third position, as shown in the figures, tension is increased on brake cable  44 , thereby engaging the dissipative braking system of vehicle  10 . The mechanism by which such braking systems operate is well known in the art. 
         [0036]    Although the embodiment of vehicle  10  described above and shown in the drawings employs a reed switch for selective engagement of the regenerative braking system, it is contemplated that any suitable switching mechanism may be used. Further, in embodiments wherein a reed switch is employed, the reed switch may be provided in either a normally-open or normally-closed state. 
         [0037]    Power System 
         [0038]    The embodiment of vehicle  10  shown in the drawings relies on solar and battery power, in addition to operator-provided power and the above-described chain drive, to propel vehicle  10  forward. Photovoltaic cells are known in the art. In such cells, sunlight impacts the solar panel and is absorbed by a semi-conducting material. Current is captured and can be utilized or stored in a battery for later use. Wiring photovoltaic cells to provide useful energy is also known in the art. Wiring may be done in one of three forms: 1) serial; 2) parallel; or 3) a combination of serial and parallel wiring. When wired in series, the positive terminal of one photovoltaic cell is connected to the negative terminal of the next photovoltaic cell. The voltage produced by each of the photovoltaic cells is additive, while the current remains constant across the system. With parallel wiring, the positive terminal of the first photovoltaic cell is connected to the positive terminal of the second photovoltaic cell, and the negative of the first photovoltaic cell is connected to the negative of the second photovoltaic cell. When wired in series, the current of the photovoltaic cells is additive while the voltage remains constant. When a combination arrangement is desired, groups of photovoltaic cells wired in series may be wired together in parallel fashion. It is contemplated that any suitable wiring scheme may be used in conjunction with the present invention. 
         [0039]    Use of a rechargeable battery is also known in the art, and it is contemplated that wiring one or more photovoltaic cells to charge such a battery is within the capabilities of one of ordinary skill in the art. A variety of batteries are available for such purposes, including lead-acid batteries, nickel metal hydride batteries, and lithium-ion batteries. Lead-acid batteries may include varieties in which the electrolyte is gelled to reduce the risk of spillage, or in which the electrolyte is absorbed in a fiberglass mat separator. Both such batteries fall into the broad category of valve-regulated lead-acid batteries. 
         [0040]      FIG. 2  shows photovoltaic cells  38  positioned on canopy  36  of vehicle  10 . Although a plurality of photovoltaic cells  38  are shown in  FIG. 2 , it is contemplated that a single, larger photovoltaic cell may be utilized. As best shown in  FIG. 6 , a rechargeable battery  30  is provided in a rear bin  68  mounted firmly on chassis  12  of vehicle  10 . The wiring from photovoltaic cells  38  to rechargeable battery  30  is not shown, however is it contemplated that one of ordinary skill in the art, having read this disclosure, would be able to wire the photovoltaic cells  38  and rechargeable batter  30  without undue experimentation. 
         [0041]    It is further contemplated that an electric motor be used in association with vehicle  10 , the electric motor converting electrical energy from battery  30  and/or photovoltaic cells  38  into mechanical energy to propel the vehicle. The electric motor may be engaged in addition to, or separately from, the chain drive assembly described above. Use of an electric motor to propel a vehicle is known in the art, and it is contemplated that any suitable motor may be used in conjunction with the present invention. 
         [0042]      FIG. 8  provides an exemplary wiring diagram of one embodiment of the present invention. As can be seen, a motor controller  74  is provided for control of hub motor  72 , and in electrical communication with “throttle” or accelerator  76 . Motor controller  74  may be provided with a wide range of functionality, including manual or automatic means for starting and stopping the vehicle, selecting forward or reverse rotation, regulating the speed of the device, regulating the torque, and protecting against overloads and faults. A variety of motor controller  74 , ranging from the simple to the complex, may be provided with the present invention. 
         [0043]    Hub motors, such as hub motor  72 , are known in the art. Hub motor  72  may include brushes for energy transfer, or may be brushless. Regenerative braking system  70  communicates electrically with hub motor  72 . Also shown in  FIG. 8  is battery  30 , as well as solar controller  78  which controls current from solar panels  38  as well as to and from battery  30 . 
         [0044]    The embodiments of the present invention described above and shown in the drawings are exemplary and are not intended to limit the present invention. Numerous modifications and alternative embodiments relating to the present invention will be readily apparent to those of skill in the art upon reading this disclosure. It is contemplated that such modifications and alternative embodiments fall within the spirit and scope of the present invention.