Abstract:
A gas augmented drive system and method for a hybrid electric vehicle. The system and method utilizes compressed gas to turn a turbine, the rotation of which generates power that can be used, among other things, to power the vehicle batteries and/or power a secondary electrical system.

Description:
RELATED APPLICATION  
       [0001]    This non-provisional application claims priority from provisional application No. 60/365,520, filed on Mar. 20, 2002. 
     
    
     
       FIELD OF INVENTION  
         [0002]    This invention relates generally to drive systems and methods and, more specifically, to a gas augmented drive system and method which, in a preferred embodiment, is for a hybrid electric vehicle.  
         BACKGROUND OF THE INVENTION  
         [0003]    In light of concerns over dwindling oil reserves and pollution, interest in electric vehicles is increasing. Major automakers have released, within the last several years, fully-electric as well as hybrid gas-electric vehicles. Yet these types of vehicles still represent only a very small minority of all vehicles sold.  
           [0004]    Among the barriers to greater acceptance of electric vehicles has been concern about their range between battery charges. The hybrid vehicle addresses this issue by providing an internal combustion engine which can provide recharging power to the batteries. However, the addition of an internal combustion engine implicates those same issues, albeit at a lower level, discussed above—dwindling oil reserves and pollution.  
           [0005]    A need therefore existed for a drive system and method for an electric vehicle which can extend the range between battery charge, yet preferably without resort (or at least with diminished reliance upon) an internal combustion engine. The drive system and method should, preferably, not increase vehicle emissions, and instead should rely on a power source that is or at least approaches zero emissions.  
           [0006]    The present invention satisfies these needs and provides other, related, advantages.  
         SUMMARY OF THE INVENTION  
         [0007]    It is an object of the present invention to provide a drive system and method for an electric vehicle which can extend the range between battery charge, without resort (or at least with diminished reliance upon) an internal combustion engine.  
           [0008]    It is a further object of the present invention to provide a drive system and method for an electric vehicle that does increase vehicle emissions, and instead relies on a power source that is or at least approaches zero emissions.  
         BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENTS  
         [0009]    In accordance with one embodiment of the present invention, a * is disclosed. The 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]    [0010]FIG. 1 is a block diagram of an embodiment of the compressed gas augmented drive according to the present invention.  
         [0011]    [0011]FIG. 2 is perspective view of an embodiment of the compressed gas driven turbine with a compressed gas supply system according to the present invention.  
         [0012]    [0012]FIG. 3 is an end, cross-sectional view of the compressed gas driven turbine with a compressed gas supply system of FIG. 2.  
         [0013]    [0013]FIG. 4 is a simplified flow chart illustrating the operation of an embodiment of the compressed gas augmented drive according to the present invention.  
         [0014]    [0014]FIG. 5 is a perspective view of an embodiment of the compressed gas augmented drive according to the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0015]    Referring to FIG. 1, an embodiment of a compressed gas augmented drive  10  for a hybrid electric vehicle according to the present invention is shown. At a basic level, the main components of the compressed gas augmented drive  10  include a compressed gas storage unit  11 , a compressed gas driven turbine  20 , at least one battery  12 , an electric motor  13 , a secondary electric system  16 , and a control unit  17 .  
         [0016]    Referring to FIGS. 2 and 3, certain of these components are illustrated. The compressed gas driven turbine  20  consists of an inertial flywheel  21  coupled to an electric generator/alternator  22 . In one preferred embodiment, the generator/alternator  22  is a combined starter/generator/alternator. As shown in FIGS. 3 and 5, the inertial flywheel  21  is preferably mounted on an axle  32 , covered by a housing  33 , and has a plurality of angled blades  31  along the perimeter thereof. (It should be noted that the configurations shown in FIGS. 3 and 5 are only intended to represent examples of a possible configuration of a flywheel useable in the gas augmented drive of the present invention. It should be understood that the term “flywheel” as used herein is intended to encompass any structure capable of being driven by compressed gas with the result that power is produced. It should also be noted that the flywheel could be driven directly by compressed gas as shown herein, or indirectly through a planetary gear system or the like.)  
         [0017]    The compressed gas supply system  30  consists of a compressed gas storage unit  11 , a compressed gas delivery system  24 , and an exhaust  25 . As shown in FIG. 5, the compressed gas preferably passes through a compressed gas regulator  23 , which regulates the flow of gas from the gas storage unit  11 , into the delivery system  24 , and into the turbine  20 . As shown in FIG. 5, the compressed gas storage unit  11  is preferably an air tank of the type typically used to store compressed air—though other gases, such as helium or nitrogen, could be used—and more than one such gas storage unit  11  can be provided.  
         [0018]    It should be noted that the compressed gas storage unit  11  could, in addition to or in place of an air tank(s), also be one or more sealed compartments within the body of the vehicle. By locating gas compartments within the vehicle body, the amount of gas storage can be increased over that possible if only traditional tanks are used. Such compartments may be formed of a plastic material, such as polyethylene or polystyrene, having some deformability. Such a construction can provide the added benefit of increasing vehicle safety, by providing impact attenuation for those portions of the vehicle where gas compartments are located. In this regard, the gas storage unit  11   a  is intended to be an example of a tank that can be positioned for impact attenuation purposes. Further, referring now to FIG. 5, it is possible to provide a filling valve  27 , in either or both the gas storage unit  11  and  11   a , so that the compressed gas also can be used to inflate objects, such as the tires of a vehicle or inflatable toys.  
         [0019]    As shown in FIGS. 2, 3 and  5 , gas is transported from the compressed gas storage unit  11  through the compressed gas delivery system  24 , towards the inertial flywheel  21 . The compressed gas delivery system  24  includes a compression port (not shown) in order to maximize the pressure inside the housing  33  as the blades  31  pass through the port. The gas is preferably pulse-injected into the housing  33  and onto the blades  31  of the inertial flywheel  21 , which pulsing can be regulated by the compressed gas regulator  23  (see FIG. 5). The preferred direction of the compressed gas injection is from the top, as shown in FIGS. 2 and 3, but an injection from the side is also possible. This injection of compressed gas causes the inertial flywheel  21  to turn or, if it is already in motion, to maintain a desired rate or to turn at a higher rate of speed. This results in production (or increased production) of electricity by the electric generator/alternator  22 , which converts the kinetic energy of the spinning inertial flywheel  21  into electrical energy. In order to prevent the building up of undue pressure within the housing  33 , gas is vented through exhaust  25 . (The vented gas (or other byproduct of the release of the gas into the surroundings) can be released as a vehicle exhaust, can be utilized to reduce engine and/or battery temperature, or can be recovered and recycled.) A relief flap (not shown) may also be provided, to vent gas so as to prevent gas pressure within the housing  33  from becoming too high.  
         [0020]    To enhance efficiency, there should be minimal tolerance between the blades  31  and the interior of the housing  33 , and the area between the blades  31  and interior of the housing  33  should be sealed.  
         [0021]    The entire system shown in FIGS. 2 and 5 is preferably mounted on a gimbal mechanism  35 , to provide a dynamic sensing purpose. As the vehicle changes plane, the inertial flywheel will resist the change, causing an inertial drag and energy loss. The gimbal  35  mechanism allows the turbine  20  to change plane without resistance and therefor reduces the energy loss through friction.  
         [0022]    The electric generator/alternator  22  shown in FIGS. 2 and 5 can be coupled to the battery  12  which powers the electric motor  13 . (The term “battery” as used herein is intended to refer to either a single battery or, more likely, to a plurality of batteries used to power an electric motor  13 .) In this fashion, the electricity produced may be used to recharge the battery  12 , extending vehicle range. Alternatively, the electric generator/alternator  22  shown in FIGS. 2 and 5 can be coupled to the vehicle&#39;s secondary electric system  16 , which includes the air conditioner, heater, power windows, power door locks, power seats, car stereo, lights, etc. By providing power to the secondary electric system  16 , the load on the battery  12  is reduced, again extending vehicle range.  
         [0023]    It would also be possible to provide more than one compressed gas driven turbine  20 , with one (or more than one) coupled to the battery  12  and one (or more than one) coupled to the secondary electrical system  16 . As yet another alternative, the compressed gas driven turbine  20  can be coupled to both the battery  12  and the secondary electrical system  16 . A gear type apparatus may also be provided in combination with the turbine  20 .  
         [0024]    Referring now to FIGS. 1 and 5, the control unit  17  is the brains of the drive  10 . It receives and analyzes signals from the electric motor  13 , the battery  12 , the generator/alternator  22 , the inertial flywheel  21 , and the compressed gas storage unit  11 . Based on the signals received, it can activate the compressed gas driven turbine  20  when needed—for example when the level of the battery  12  falls below a certain level. The introduction of compressed gas into the turbine  20  will be continuously modulated, with more gas being added under high load conditions and less gas being added under low load conditions.  
         [0025]    Referring now to FIG. 4, the operation of the compressed gas augmented drive  10  according to the present invention is shown. As the vehicle  10  is operated, the control unit  17  will monitor the different components of the drive  10 . When a specified condition is present, an appropriate instruction is sent by the control unit  17  to the relevant system component for action. For example, if the level of the battery  12  falls below a certain value, the control unit  17  will send an instruction to activate the compressed gas storage unit  11 . This will result in the delivery of compressed gas to the turbine  20 , the production of electricity (or increased production of electricity) by the electric generator  22 , and the delivery of that electricity to the battery  12  and/or to the vehicle&#39;s secondary electrical system  16 . When sufficient electricity has been produced, the control unit  17  will send an instruction ceasing the delivery of compressed gas or reducing its flow. This operation can take place while the vehicle is being operated or while the vehicle is at rest.  
         [0026]    In one preferred embodiment, as shown in FIG. 5, the compressed gas augmented drive  10  can be combined with a solar battery  40  assisting the main battery. Using sensors the control unit  17  will detect the input from the solar battery  40  and adjust the input of compressed gas accordingly.  
         [0027]    While the invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that the foregoing and other changes in form and details may be made therein without departing from the spirit and scope of the invention.  
         [0028]    For example, while the use of a compressed gas augmented drive has been discussed for a hybrid electric vehicle, such a drive could be used to augment electric motors powering virtually any device—and is not limited solely to use with vehicles. Moreover, while in the preferred embodiment the compressed gas augmented drive replaces the internal combustion engine or other power source used to augment the batteries supplying power to an electric motor, the compressed gas augmented drive could be used in combination with an internal combustion engine—so as to reduce the load on the internal combustion engine and allow it to achieve greater fuel efficiency and improved emissions performance.