Abstract:
An energy conversion apparatus and method using recovered energy sources including motor vehicle kinetic energy (deceleration and shock) and wind resistance, supplemented by liquefied air transferred to the vehicle and by solar radiation thereto. The energy sources are combined, as available, to drive a compressor for supplying intake working fluid of a motor vehicle prime mover, wherein liquefied air provides pre-compression cooling of an atmospheric air portion of the working fluid. The liquefied air is made by recovered energy, stored and transferred between vehicles and between vehicles and stationary sites. In a hybrid version of the vehicle, exhaust heat from a combustion engine part of the prime mover increases working fluid temperature in a gas expander part, thereof; the engine and expander operating independently or together for improved vehicle propulsion efficiency.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims priority of Provisional Application Ser. No. 60/571,640, filed May 17, 2004. 
     
    
     REFERENCES CITED  
       [0002]    
       
         
               
               
               
               
             
           
               
                   
               
               
                   
               
             
             
               
                 1,671,033 
                 May 1928 
                 Klmura 
                 290/14 
               
               
                 3,688,859 
                 September 1972 
                 Hudspeth and Lunsford 
                 180/302 
               
               
                 6,138,781 
                 October 2000 
                 Hakala 
                 180/2.2 
               
               
                 5,725,062 
                 March 1998 
                 Fronek 
                 180/2.2 
               
               
                 4,182,960 
                 January 1980 
                 Reuyl 
                 290/1R 
               
               
                 4,294,323 
                 October 1981 
                 Boese 
                 180/69.5 
               
               
                 3,525,874 
                 August 1970 
                 Toy 
                 290/14 
               
               
                 3,566,717 
                 March 1971 
                 Berman 
                 477/3 
               
               
                   
               
             
          
         
       
     
       Other Publications  
       [0003]     “Ultra-Low Emission Liquid Nitrogen Automobile”Knowlen, Mattick, Hertzberg, and Bruckner, University of Washington, SAE-1999-0102932, 1999  
         [0004]     “Cryogenic Heat Engines for Powering Zero Emission Vehicles”, Ordonez, Plummer, and Reidy, University of North Texas IMEECE2001/PID-25620, 2001  
       BACKGROUND OF THE INVENTION  
       [0005]     This invention presents an energy converter to recover and combine diverse motor vehicle energy sources for supplying compressed working fluid to a motor vehicle prime mover, wherein a liquefied air portion of the working fluid provides pre-compression cooling of an atmospheric air portion thereof; the liquefied air being made by recovered energy, stored and transferred between vehicles and between vehicles and stationary sites.  
         [0006]     Increased fuel mileage and range in conjunction with low grade fuels has long been a goal of automotive design, to make driving more economical, to conserve fossil fuels, and to reduce emission of combustion products. Recovery and combining of vehicle energy sources as available, including kinetic (deceleration and shock), wind resistance, and solar radiation, is not described in the prior art. In addition, coordinated storage and transfer of recovered energy using pneumatic, cryogenic and electric systems is not described in the prior art. Recovery of only the deceleration component of kinetic energy, coordinated with electrical transfer between batteries and generators, is used in lightweight hybrid vehicles to provide limited performance improvement. Relevant vehicle energy recovery and consumption devices described in the prior art have disadvantages, as follows:  
         [0007]     (a) U.S. Pat. No. 1,671,033 to Kimura (1928) describes a transmission with an electric generator and battery storage for recovery of vehicle deceleration, the component of vehicle kinetic energy in the direction of travel. The recovered energy, normally dissipated by engine compression and vehicle braking, is stored in batteries and used for limited electrical power assist. Deceleration energy is not completely recoverable due in part to insufficient battery capacity.  
         [0008]     (b) U.S. Pat. No. 3,688,859 to Hudspeth and Lunsford (1972) describes compressors connected between the frame and axles of a vehicle for recovery of shock, the upward component of vehicle kinetic energy. The recovered energy, normally dissipated by shock absorbers, is used for limited pneumatic power assist. Shock energy is not completely recoverable due to compression heating.  
         [0009]     (c) U.S. Pat. No. 6,138,781 to Hakala (2000) describes an electric generator for recovery of vehicle wind energy. The recovered energy, normally dissipated by vehicle drag force, is used for limited electrical power assist. Potential wind energy recovery is not realized because air from a wind recovery device is discharged to relatively high wake pressure. In addition, aerodynamic vehicle shapes are often used to reduce drag loss at the expense of vehicle function, such as carrying capacity.  
         [0010]     (d) U.S. Pat. No. 5,725,062 to Fronek (1998) describes the use of a solar photo-voltaic panel atop a vehicle for recovery of solar energy radiating to a vehicle. The recovered energy, normally dissipated to the atmosphere, is used for limited electrical power assist. Solar radiation to a vehicle is not completely recoverable due in part to insufficient battery capacity.  
         [0011]     (e) U.S. Pat. No. 4,182,960 to Reuyl (1980) describes transfer of electrical energy between vehicles and stationary sites. Solar energy recovered at a site is stored in batteries to provide power to the site and a portion is transferred to, and stored in batteries in a hybrid gas turbine-electric vehicle. The gas turbine can provide power to the site via an electric generator to supplement site solar energy. Battery storage problems include space and weight limitation, trade-off between battery life and energy discharged, replacement handling, charge time, and ventilation.  
         [0012]     Research programs at the University of Washington (“Ultra-Low Emission Liquid Nitrogen Automobile”Knowlen, Mattick, Hertzberg, and Bruckner, SAE-1999-0102932, 1999) and the University of North Texas (“Cryogenic Heat Engines for Powering Zero Emission Vehicles”, Ordonez, Plummer, and Reidy, IMEECE2001/PID-25620, 2001) describe a liquefied gas system to supply liquid nitrogen for on-board storage and use in zero emissions vehicles powered by ambient temperature heat engines. Transfer of liquefied gas between vehicles and from vehicles to stationary sites, for use thereof, is not described in the prior art. Liquefied gas transfer problems include boil-off and fill and drain connection.  
         [0013]     (f) The prior art describes several types of gas liquefiers including; vapor-compression, magnetic, Stirling cycle and thermo-acoustic, for stationary application. State-of-the-art air liquefiers require compression work of approximately 2.5 times the heat removed per 2.2 kg (1 lb) of air liquefied.  
         [0014]     (g) Gas turbine engine powered vehicles are described in the prior art and were produced by Rover and by Chrysler Corporation during the 1950&#39;s and 1960&#39;s. Gas turbine engines require high turbine inlet temperature to provide acceptable thermal efficiency. Other problems include high compression work, high turbine blade and exhaust gas temperature, and expensive heat exchangers. Operation is characterized by falling efficiency with load and compression braking is unavailable. Low grade fuels such as kerosene can be burned, however emissions are high due to high fuel consumption and formation of compounds at high temperature.  
         [0015]     (h) U.S. Pat. No. 4,294,323 to Boese (1981) describes a gas expander using cryogenic liquid working fluid. Cryogenic expanders have low specific expansion energy due to heat input at ambient temperature. Research programs at the University of Washington (“Ultra-Low Emission Liquid Nitrogen Automobile” Knowlen, Mattick, Hertzberg, and Bruckner, SAE-1999-0102932, 1999) and at the University of North Texas (“Cryogenic Heat Engines for Powering Zero Emission Vehicles”, Ordonez, Plummer, and Reidy, IMEECE2001/PID-25620, 2001) describe development of liquid nitrogen expanders with emphasis on maximizing output by designing for quasi-isothermal expansion. Expanders have limited usefulness in lightweight, short range, low speed vehicles for zero emission urban use.  
         [0016]     (i) U.S. Pat. No. 3,525,874 to Toy (1970) describes a hybrid gas turbine-electric prime mover, and U.S. Pat. No. 3,566,717 to Berman (1971) describes a hybrid transmission for parallel operation of a combustion engine and an electric motor. Recovered deceleration energy, normally dissipated by engine compression and vehicle braking, is stored in batteries and used for power assist in hybrid vehicles. Combustion engine efficiency is low, and deceleration is not completely recoverable due in part to insufficient battery capacity.  
       SUMMARY OF THE INVENTION  
       [0017]     It is an object of the present invention, therefore, to provide systems for recovery of energy dissipated by a motor vehicle, as well as solar radiation.  
         [0018]     It is another object of the present invention to provide systems for storage and transfer of recovered energy.  
         [0019]     It is still another object of the present invention to provide systems for efficient consumption of recovered energy.  
         [0020]     It is yet another object of the present invention to provide a prime mover capable of burning renewable fuel with improved emissions.  
         [0021]     In keeping with these objects and others which may become apparent the present invention seeks to provide a unified energy system to recover, store, transfer and consume energy dissipated by motor vehicles, or otherwise available thereto. In essence, combining recoverable energy sources as available yields greater benefit than when taken individually. For example, full potential of a gas turbine is realized using recovered energy to provide the compressed air requirement.  
         [0022]     Combined recovery of vehicle energy sources including kinetic (deceleration and shock), wind resistance, and solar radiation to compress atmospheric air provides substantial vehicle power assist. Recovery is by compression of atmospheric air for consumption as working fluid in vehicle prime movers. Liquefied air is imported to the vehicle as a form of energy storage by providing pre-compression cooling of prime mover working fluid. In addition, a liquefier makes supplementary liquefied air using excess recovered energy, such as during high speed driving when vehicle wind resistance, a function of the third power of speed, predominates. Excess liquefied air is transferred from the vehicle for use in other vehicles or at stationary sites. The recoverable portion of energy dissipated by a vehicle, estimated in accordance with standard highway driving cycle US-06, is: deceleration, 25%; wind resistance, 10%; shock, 10%. In addition 91 kg (200 lb) of imported liquefied air effectively increases the recovered total by 25% and clear day solar radiation adds another 8%. Energy recovery by diverse means enhances performance over a wide range of driving conditions, providing a three-fold increase in prime mover efficiency, because prime mover compression by recovered energy is a virtual energy loss. Accordingly, advantages of the present invention are illustrated as follows:  
         [0023]     (a) A feature of the energy system in accordance with the present invention lies in providing an energy recovery transmission for recovery of vehicle deceleration energy by compression of atmospheric air.  
         [0024]     (b) Another feature of the energy system in accordance with the present invention lies in providing energy recovery shock absorbers with cryogenic cooling for efficient compression of atmospheric air.  
         [0025]     (c) Another feature of the energy system in accordance with the present invention lies in providing an energy recovery turbine to drive an atmospheric air compressor. The turbine operates on the difference between wind impact pressure and wake pressure at high suction locations behind an air dam, the windshield/roof intersection, and other leading edges. Vehicle shapes are designed for the best use of recovered wind energy as it effects vehicle cost, carrying capacity and style.  
         [0026]     (d) Another feature of the energy system in accordance with the present invention lies in providing an energy recovery solar-electric panel to drive an atmospheric air compressor. Energy is recovered during parking, stopping and driving of a vehicle.  
         [0027]     (e) Another feature of the energy system in accordance with the present invention lies in providing air compression and liquefied air storage of recovered energy, plus capability to transfer liquefied air between vehicles or between vehicles and stationary sites. In addition, air compression provides vehicle braking assist.  
         [0028]     (f) Another feature of the energy system in accordance with the present invention lies in providing an on-board vehicle air liquefier to liquefy suitably pure atmospheric air. Required liquefier compression is equivalent to that of state-of-the-art liquefiers, however work input using recovered vehicle energy is a virtual energy loss.  
         [0029]     (g) Another feature of the energy system in accordance with the present invention lies in providing a compact and efficient gas turbine prime mover. Compression work, using recovered vehicle energy above approximately 25% turbine load, is a virtual energy loss. Pre-compression cooling of working fluid with liquefied air enables reduced turbine inlet and exhaust temperatures. Heat input is from a renewable fuel, such as methanol. Efficiency is relatively constant over the load range and low fuel consumption lowers emissions while  
         [0030]     (h) Another feature of the energy system in accordance with the present invention lies in providing a quasi-isothermal liquefied air expander for urban driving. Compression work, using recovered vehicle energy, is a virtual energy loss.  
         [0031]     (i) Still another feature of the energy system in accordance with the present invention lies in providing a gas turbine/air expander with virtual compression to power a hybrid vehicle. The gas turbine operates independently and efficiently over a wide load range. The expander and gas turbine operate in parallel with the added benefit of turbine exhaust heat recovery into the working fluid of the expander. The expander operates independently during urban driving when the gas turbine is least efficient.  
         [0032]     Other general and more specific objects and advantages of the present invention will in part be obvious and will in part appear from the drawings and description which follows. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0033]     Objects and advantages of the present invention will become apparent from the following when read in conjunction with the accompanying drawings and reference numerals list, wherein solid lines connecting components indicate fluid flow, arrows indicate flow direction, and dashed lines indicate electrical connection:  
         [0034]      FIG. 1  is a schematic illustration showing connection of components of an energy recovery, storage, transfer and consumption system in a motor vehicle.  
         [0035]      FIG. 2  is a schematic illustration of one of four shock compressors connected in the motor vehicle of  FIG. 1 .  
         [0036]      FIG. 3  is a schematic illustration of a solar electric panel connected to drive an air compressor in the motor vehicle of  FIG. 1 .  
     
    
     REFERENCE NUMERALS  
       [0000]    
       FIG. 1 
     
         [0000]    
       
           10  vehicle  
           11  gas turbine engine  
           12  air expander  
           13  transmission-generator drive  
           14  shaft  
           15  rear wheel-axle assembly  
           16  motor controller  
           17  motor-compressor  
           18  axial wind drive  
           19  clutch  
           20  motor-compressor shaft  
           21  windshield  
           22  air dam  
           23  compartment  
           24  air duct  
           25  compressed air tank  
           26  air liquefier  
           27  liquefier intake valve  
           28  liquid air tank  
           29  vent valve  
           30  liquid air fill valve  
           31  liquid air drain valve  
           32  liquid air pump  
           33  evaporator  
           34  header  
           35  pumped air valve  
           36  compressed air valve  
           37  throttle  
           38  expander valve  
           39  gas turbine  
           40  combuster  
           41  recuperator  
           42  fuel tank  
           43  fuel pump  
           44  heating jacket  
           45  circulating fan 
   FIG. 2   
           46  shock compressor drive (typical)  
           47  front wheel-axle assembly 
   FIG. 3   
           48  solar photo-voltaic panel  
       
     
       DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0076]      FIG. 1  illustrates a preferred embodiment of the energy recovery, storage, transfer and consumption system of the present invention installed in a motor vehicle  10 . An engine  11  combined with an air expander  12  by a transmission-generator drive  13  provides prime mover propulsion to the vehicle via a shaft  14  and a rear wheel-axle assembly  15 . Deceleration energy is recovered by drive  13 , which is electrically connected to a motor controller  16  to power a motor-compressor  17 . Wind energy is recovered by an axial wind drive  18  connected to motor-compressor  17  through a clutch  19 , which provides torque to a motor-compressor shaft  20  when wind energy is sufficient. Drive  18  operates on the difference between impact pressure and wake suction pressure behind a windshield  21  and an air dam  22 . Impact air pressurizes a compartment  23  and discharges through an air duct  24 . Motor-compressor  17  compresses air into a compressed air tank  25 . An air liquefier  26  draws atmospheric air through a liquefier intake valve  27  and discharges liquefied air to a liquefied air tank  28  while venting through a vent valve  29 . liquefied air is transferred to the vehicle into tank  28  through a liquefied air fill valve  30  and transferred from the vehicle through a liquefied air drain valve  31 .  
         [0077]     Liquefied air is pressurized by a liquefied air pump  32  and vaporizes while cooling atmospheric air in an evaporator  33 . The cooled air is pressurized by motor-compressor  17 , mixed with the vaporized air in a header  34 , and the mixture delivered to the engine and the expander under control of a pumped air valve  35  and a compressed air valve  36 . The ratio of expander air to combustion air is controlled by a throttle  37  and an expander valve  38 .  
         [0078]     Engine  11  is a gas turbine  39  connected to a combustor  40  and a recuperator  41 . Fuel is stored in a fuel tank  42  and pressurized by a fuel pump  43 . Combustion products from the recuperator pass through a heating jacket  44  of the expander to atmosphere.  
         [0079]     Evaluation of vehicle highway performance is based on US-06 (Supplemental Federal Test Procedure) for 6 hours at average speed of 77 km/hr (48 mph). US-06 is the most aggressive real highway driving cycle and illustrates the combination of deceleration drive  13  and wind drive  18 . Methanol fuel is selected because it is renewable, air requirements are low due to oxygen content, and large scale production is enabled by use in high efficiency engines. With an initial fill of 91 kg (200 lb) of liquefied air, “gasoline equivalent mileage”is 25 km/l (150 mpg) and liquefied air consumption is 113 kg (250 lb), for a distance 463 km (288 mi). Evaluation of vehicle urban performance is based on LA-92 (California Air Resources Board) for 4 hours at average speed of 40 km/hr (25 mph). LA-92 is the most aggressive real urban driving cycle and illustrates operation when vehicle speed is too low for effective recovery of wind energy. Efficient operation is with engine  11  off, expander  12  operating on air from tank  25 , and wind drive  18  disengaged by clutch  19 . With an initial fill of 91 kg (200 lb) of liquefied air, “liquefied air equivalent mileage”is 1.9 km/kg (0.53 mi/lb) for a distance 161 km (100 mi).  
         [0080]     Drive  13  recovers deceleration energy while prime mover air consumption drops, providing electrical power to motor-compressor  17  and liquefier  26  based on pressure in tank  25 . Drive  18  recovers wind energy during forward motion of the vehicle above approximately 56 km/hr (35 mph) due to difference of 2.5 velocity heads between vehicle impact pressure and wake suction pressure behind windshield  21  and air dam  22 . Excess wind energy for liquefied air production is recovered at an increasing rate, proportional to the third power of vehicle speed. Estimated deceleration recovery is 75% of vehicle acceleration and estimated wind recovery is 25% of vehicle wind resistance.  
         [0081]     Quasi-isentropic motor-compressor  17  normally maintains expander and engine air pressure in tank  25  at 300 K (540 R), 4 mPa (40 atm) with valve  27  and  30  closed and valves  35  and  36  open. Estimated efficiency of the motor compressor is 80%.  
         [0082]     Air liquefier  26  operates on over-pressure in tank  25  to deliver 23 kg (50 lb) of liquefied air to tank  28  during 6 hours of US-06 driving with valve  29  open and valves  27  and  30  closed. Estimated liquefaction energy is 1395 kj/kg (600 btu/lb) of liquefied air produced; approximately twice the ideal and one-half the energy input of commercial liquefiers.  
         [0083]     Combined engine  11  and expander  12  deliver up to 71 kW (95 hp) to meet US-06 vehicle acceleration. Engine output is 15100 kJ/kg (6500 btu/lb) of fuel with an air-fuel ratio of 15, and turbine inlet temperature is 1500 K (2700 R) at 4.0 mPa (40 atm). Methanol consumption is 1.5 kg/hr (3.3 lb/hr) with total liquefied air of 19 kg/hr (42 lb/hr). Engine exhaust gas, including latent heat of condensable products, maintains jacket  45  inlet air temperature of 444 K (800 R) at 4.0 mPa (40 atm), and exhaust temperature of 300 K (540 R). Expander output is 1400 kJ/kg (600 btu/lb) of liquefied air, and drops by 50% with the engine off and no exhaust heating. Estimated engine and expander efficiencies are 85%.  
         [0084]      FIG. 2  illustrates an embodiment of the present invention for recovery of vehicle shock energy. A four shock compressor drive  45  (typical), connected to each end of rear wheel-axle assembly  15  and to each end of a front wheel-axle assembly  46 , provides compressed air from evaporator  33  into tank  25 .  
         [0085]     Drive  45  recovers an additional 9% of US-06 driving resistance, increasing fuel mileage of the  FIG. 1  configuration by 12% and liquefier output by 58%. Air from evaporator  33  at 94 K (170 R) is compressed into tank  25  at 300 K (540 R), 4 mPa (40 atm) by action of the shock compressor drive due to reciprocating wheel-axle motion. Recovered shock energy is estimated at 30% of rolling resistance, a function of road surface roughness, vehicle speed, and tire pressure, as well as bearing friction.  
         [0086]      FIG. 3  illustrates an embodiment of the present invention for recovery of solar radiation by a solar photo-voltaic panel  47  atop the vehicle. Electrical output from the panel to controller  16  powers motor-compressor  17  and liquefier  26 .  
         [0087]     Panel  47  recovers an equivalent 8% of US-06 driving resistance, increasing fuel mileage of the  FIG. 1  configuration by 8% and liquefier output by 48%. Because energy recovery also occurs during vehicle inactivity, liquefier output accumulates. Recovered energy is based on a representative 4.6 m2 (50 ft2), 20% efficient panel in sun. Atmospheric air is compressed into tank  25  at 300 K (540 R), 4 mPa (40 atm).  
         [0088]     Although the description above contains many specifics, these should not be construed as limiting the scope of the invention, but only to provide illustrations of some of the preferred embodiments of this invention. For example;  
         [0089]     The energy recovery, storage, transfer and consumption system of the present invention can be used in trucks and other vehicle types using any suitable fuel or working fluid.  
         [0090]     Deceleration, wind, shock and solar energy can be recovered in combination to provide mechanical or electrical drive of prime mover working fluid compressors or other vehicle components.  
         [0091]     Electric batteries can be used to supplement energy storage.  
         [0092]     Vapor-compression, two phase expansion, magnetic, thermo-acoustic, thermo-electric and Stirling liquefiers can be used, and emissions features such as air separation for constituent liquefaction can be added. A liquefier expansion-engine can be used for power assist of vehicle components.  
         [0093]     Diesel or other engine types can be used separately or in combination with a gas expander as series or parallel hybrid prime movers. A gas turbine engine can have performance features such as working fluid reheat; and emissions features such as separation of carbon dioxide from combustion products, support of combustion by oxygen enriched air, and combustion cooling by water, nitrogen or other fluid. A gas expander can have performance features such as injection of heat transfer fluid to increase temperature and improve expansion isothermicity of the working fluid.  
         [0094]     Thus the scope of the invention should be determined by the appended claims and their legal equivalents, rather than the examples given.