Abstract:
One embodiment of the present invention is a unique vehicle. Another embodiment is a unique propulsion system. Yet another embodiment is a unique system. Other embodiments include apparatuses, systems, devices, hardware, methods, and combinations for vehicle propulsions systems. Further embodiments, forms, features, aspects, benefits, and advantages of the present application will become apparent from the description and figures provided herewith.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application claims benefit of U.S. Provisional Patent Application No. 61/428,707, filed Dec. 30, 2010, entitled SYSTEM, PROPULSION SYSTEM AND VEHICLE, which is incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to powered systems, and more particularly, gas turbine powered systems, propulsion systems and vehicles. 
       BACKGROUND 
       [0003]    Propulsion systems that effectively use gas turbine engines as sources of power, remain an area of interest. Some existing systems have various shortcomings, drawbacks, and disadvantages relative to certain applications. Accordingly, there remains a need for further contributions in this area of technology. 
       SUMMARY 
       [0004]    One embodiment of the present invention is a unique vehicle. Another embodiment is a unique propulsion system. Yet another embodiment is a unique system. Other embodiments include apparatuses, systems, devices, hardware, methods, and combinations for vehicle propulsions systems. Further embodiments, forms, features, aspects, benefits, and advantages of the present application will become apparent from the description and figures provided herewith. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0005]    The description herein makes reference to the accompanying drawings wherein like reference numerals refer to like parts throughout the several views, and wherein: 
           [0006]      FIG. 1  schematically illustrates some aspects of a non-limiting example of one of many types of vehicles in accordance with an embodiment of the present invention. 
           [0007]      FIG. 2  schematically illustrates some aspects of a non-limiting example of a propulsion system for a vehicle in accordance with an embodiment of the present invention. 
           [0008]      FIG. 3  schematically illustrates some aspects of a non-limiting example of a propulsion system for a vehicle in accordance with an embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0009]    For purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings, and specific language will be used to describe the same. It will nonetheless be understood that no limitation of the scope of the invention is intended by the illustration and description of certain embodiments of the invention. In addition, any alterations and/or modifications of the illustrated and/or described embodiment(s) are contemplated as being within the scope of the present invention. Further, any other applications of the principles of the invention, as illustrated and/or described herein, as would normally occur to one skilled in the art to which the invention pertains, are contemplated as being within the scope of the present invention. 
         [0010]    Referring to  FIG. 1 , there are illustrated some aspects of a non-limiting example of a vehicle  10  in accordance with an embodiment of the present invention. In one form, vehicle  10  is an aircraft, referred to herein as aircraft  10 . In other embodiments, vehicle  10  may be any type of engine powered vehicle, including one or more types of air-vehicles; land vehicles, including and without limitation, tracked and/or wheeled vehicles; marine vehicles, including and without limitation, surface vessels, submarines and/or semi-submersibles; amphibious vehicles, or any combination of one or more types of air, marine and land vehicles. In various forms, vehicle  10  may be manned and/or autonomous. 
         [0011]    In one form, aircraft  10  includes a fuselage  12 , wings  14 , an empennage  16  and propulsion systems  18 . In one form, aircraft  10  is a twin engine turbofan aircraft. In other embodiments, aircraft  10  may be any fixed-wing aircraft, including turbofan aircraft and turboprop aircraft. In various embodiments, aircraft  10  may take various forms, including, without limitation, fixed-wing aircraft, rotary wing aircraft and/or lighter-than-air aircraft. In various embodiments, aircraft  10  may have a single propulsion system  18  or a plurality of propulsion systems  18 . In various embodiments, aircraft  10  may employ any number of wings  14 , or may not include any wings. Empennage  16  may employ a single flight control surface or multiple flight control surfaces, or may not be included in some embodiments. In one form, aircraft  10  includes a cabin  19 . In one form, cabin  19  is configured to hold, for example and without limitation, one or more pilots, technicians, weapon or other specialists and/or passengers, and is positioned in fuselage  12 . In various embodiments, cabin  19  may be configured to hold any type of payload, human and/or nonhuman, and may be pressurized and/or nonpressurized. Although depicted in the form of an aircraft cabin, in other embodiments, cabin  19  may be any air-vehicle, land vehicle and/or marine vehicle cabin. 
         [0012]    Referring to  FIG. 2 , there are illustrated some aspects of a non-limiting example of propulsion system  18  in accordance with an embodiment of the present invention. Propulsion system  18  includes a gas turbine engine  20  and an auxiliary power unit  22  (APU  22 ). Although described herein as with respect to an aircraft propulsion system, in other embodiments, propulsion system  18  may be a propulsion system for providing propulsive thrust to one or more other types of vehicles, e.g., air-vehicles; land vehicles, including tracked and/or wheeled vehicles (e.g., battle tanks); marine vehicles, including surface vessels, submarines and/or semi-submersibles; amphibious vehicles; or any combination of one or more types of air, marine and land vehicles. The propulsive thrust provided by propulsion system  18  for an air vehicle in the form of one or more fast moving streams of air generated by one or more propulsors, for example and without limitation, one or more turbofans, propellers, turbines, propfans and/or other rotor systems that generate thrust. The propulsive thrust provided by propulsion system  18  to land-based vehicles may include the tractive effort provided via one or more propulsors in the form of, for example and without limitation, wheels and/or tracks, e.g., using one or more transmissions. The propulsive thrust provided by propulsion system  18  to a marine vehicle may be in the form of one or more fast moving streams of water generated by one or more propulsors in the form of, for example and without limitation, one or more propellers, shrouded and/or not shrouded; hydrojets and/or jet-pumps. 
         [0013]    In one form, APU  22  is a secondary gas turbine engine. In other embodiments, APU  22  may be one or more other types of thermodynamic machines configured to generate mechanical power from fuel, which may be used to drive other mechanical and/or electro-mechanical machines, e.g., including generators, refrigeration systems, thermal management systems and/or any other type of machine. For example, in some embodiments, APU  22  may be a turbocharged, supercharged and/or normally aspirated piston engine or a hybrid engine. 
         [0014]    In the form of an aircraft engine, engine  20  is a primary propulsion engine that provides thrust for flight operations of aircraft  10 . In one form, engine  20  is a two spool engine having a high pressure spool  24  and a low pressure spool  26 . In other embodiments, engine  20  may include three or more spools. In one form, engine  20  is a turbofan engine, wherein low pressure spool  26  powers a propulsor  28  in the form of a turbofan (fan) system, referred to herein as a turbofan or a fan system, which is configured to impart motion to aircraft  10  during normal aircraft moving operations, e.g., flying aircraft  10  through air. In other embodiments, engine  20  may be a turboprop engine, wherein low pressure spool  26  powers a propulsor  28  in the form of a propeller system (not shown), e.g., via a reduction gearbox (not shown). In one form, a single engine  20  is coupled to each wing  14  of aircraft  10 . In other embodiments, more than one engine  20  may be coupled to each wing  14 . In still other embodiments, one or more engines  20  may be coupled to the fuselage or the empennage in addition to or in place of wing-mounted engines  20 . In embodiments wherein the vehicle is a land-based vehicle, propulsor  28  may be, for example and without limitation, a wheel and/or track drive system configured to impart motion to the vehicle during normal vehicle moving operations, e.g., driving the vehicle across surfaces. In embodiments wherein the vehicle is a marine vehicle, propulsor  28  may be, for example and without limitation, one or more propellers, shrouded and/or not shrouded; hydrojets and/or jet-pumps configured to impart motion to the vehicle during normal vehicle moving operations, e.g., driving the vehicle through water. 
         [0015]    In one form, engine  20  includes, in addition to fan system  28 , a bypass duct  30 , a compressor system  32 , a diffuser  34 , a combustion system  36 , a high pressure (HP) turbine system  38 , a low pressure (LP) turbine system  40 , a nozzle  42 A, and a nozzle  42 B. In other embodiments, there may be, for example, an intermediate pressure spool having an intermediate pressure turbine system. In various embodiments, engine  20  may also include an electrical machine  44  coupled to low pressure spool  26 , and an electrical machine  46  coupled to high pressure spool  24 . In one form, each of electrical machines  44  and  46  are operative to convert mechanical power to electrical power, and to convert electrical power to mechanical power, e.g., as in a motor/generator. Other embodiments may not include an electrical machine on low pressure spool  26  and/or high pressure spool  24 . 
         [0016]    In the depicted embodiment, the engine core flow is discharged through nozzle  42 A, and the bypass flow is discharged through nozzle  42 B. In other embodiments, other nozzle arrangements may be employed, e.g., a common nozzle for core and bypass flow; a nozzle for core flow, but no nozzle for bypass flow; or another nozzle arrangement. Bypass duct  30  and compressor system  32  are in fluid communication with fan system  28 . Nozzle  42 B is in fluid communication with bypass duct  30 . Diffuser  34  is in fluid communication with compressor system  32 . Combustion system  36  is fluidly disposed between compressor system  32  and turbine system  38 . Turbine system  40  is fluidly disposed between turbine system  38  and nozzle  42 B. In one form, combustion system  36  includes a combustion liner (not shown) that contains a continuous combustion process. In other embodiments, combustion system  36  may take other forms, and may be, for example, a wave rotor combustion system, a rotary valve combustion system, or a slinger combustion system, and may employ deflagration and/or detonation combustion processes. 
         [0017]    Fan system  28  includes a fan rotor system  48 . In various embodiments, fan rotor system  48  includes one or more rotors (not shown) that are powered by turbine system  40 . Fan system  28  may include one or more vanes (not shown). Bypass duct  30  is operative to transmit a bypass flow generated by fan system  28  around the core of engine  20 . Compressor system  32  includes a compressor rotor system  50 . In various embodiments, compressor rotor system  50  includes one or more rotors (not shown) that are powered by turbine system  38 . Turbine system  38  includes a turbine rotor system  52 . In various embodiments, turbine rotor system  52  includes one or more rotors (not shown) operative to drive compressor rotor system  50 . Turbine rotor system  52  is drivingly coupled to compressor rotor system  50  via a shafting system  54 . Turbine system  40  includes a turbine rotor system  56 . In various embodiments, turbine rotor system  56  includes one or more rotors (not shown) operative to drive fan rotor system  48 . Turbine rotor system  56  is drivingly coupled to fan rotor system  48  via a shafting system  58 . In various embodiments, shafting systems  54  and  58  include a plurality of shafts that may rotate at the same or different speeds and directions. In some embodiments, only a single shaft may be employed in one or both of shafting systems  54  and  58 . Turbine system  40  is operative to discharge an engine  20  core flow to nozzle  42 A. 
         [0018]    During normal operation of gas turbine engine  20 , air is drawn into the inlet of fan system  28  and pressurized by fan rotor system  48 . Some of the air pressurized by fan rotor system  48  is directed into compressor system  32  as core flow, and some of the pressurized air is directed into bypass duct  30  as bypass flow. Compressor system  32  further pressurizes the portion of the air received therein from fan system  28 , which is then discharged into diffuser  34 . Diffuser  34  reduces the velocity of the pressurized air, and directs the diffused core airflow into combustion system  36 . Fuel is mixed with the pressurized air in combustion system  36 , which is then combusted. The hot gases exiting combustion system  36  are directed into turbine systems  38  and  40 , which extract energy in the form of mechanical shaft power to drive compressor system  32  and fan system  28  via respective shafting systems  54  and  58 . 
         [0019]    Referring to  FIG. 3 , some aspects of a non-limiting example APU  22  and some of its connections to engine  20  in accordance with an embodiment of the present invention is schematically depicted. APU  22  is coupled to low pressure spool  26 . APU  22  is operative to supply mechanical rotational power to low pressure spool  26  for taxiing aircraft  10  without starting engine  20 . In one form, APU  22  is coupled to low pressure spool  26  via shaft  58 , to directly drive low pressure spool  26 . In other embodiments, other arrangements may be employed to drive low pressure spool  26  using shaft power generated by APU  22 . In still other embodiments, APU  22  may be coupled to any engine  20  spool for directly driving such spool, including the single spool of a single spool engine or any spool of a multispool engine. 
         [0020]    In one form, APU  22  is configured to supply rotational power to low pressure spool  26  to provide sufficient thrust to taxi aircraft  10  without starting one or more engines  20 . In one form, the taxiing thrust is produced by propulsor  28 . In other embodiments, APU  22  may be configured to supply rotational power to generate thrust for other vehicle types, e.g., vehicle types as mentioned above. 
         [0021]    In one form, APU  22  includes an APU compressor  60 , an APU combustor  62 , an APU turbine  64 , a reduction gearbox  66  and an electrical machine  68 . In other embodiments, APU  22  may take one or more other forms. The discharge of compressor  60  is in fluid communication with combustor  62 . The discharge of combustor  62  is in fluid communication with turbine  64 . Turbine  64  is coupled to compressor  60  and operative to drive compressor  60 . In one form, reduction gearbox  66  is coupled to and driven by turbine  64 . In other embodiments, reduction gearbox  66  may be coupled to compressor  60  and driven by turbine  64  via compressor  60  or a shaft extending from turbine  64 . In one form, reduction gearbox  66  is considered a part of APU  22 . In other embodiments, reduction gearbox  66  may be considered a separate component that is powered by APU  22 . For example, in one form, gearbox  66  may be an accessory gearbox of engine  20 , whereas in another form, gearbox  66  may be coupled to a separate accessory gearbox of engine  20 . In one form, electrical machine  68  is coupled to compressor  60 . In other embodiments, other mechanical arrangements may be employed. For example, electrical machine  68  may be coupled directly to turbine  64 . 
         [0022]    Electrical machine  68  is operative to convert mechanical power received from APU  22  into electrical power. In some embodiments, electrical machine  68  may be also configured to convert electrical power to mechanical power, e.g., for starting APU  22 . In some embodiments, a power conditioner  70  is electrically coupled to electrical machine  68  and operative to condition the power output of electrical machine  68 , e.g., for use in supplying electrical power to one or more systems of aircraft  10  during aircraft  10  ground operations and/or flight operations. In some embodiments, electrical machine  68  is configured to provide electrical power to drive electrical machine  44  and/or electrical machine  46 . For example, in one form, power generated by electrical machine  68  may be employed to start or to aid in the starting of engine  20  by providing electrical power to electrical machines  44  and/or  46 . In the depiction of  FIG. 3 , a line  72  indicates an electrical coupling of electrical machine  46  to power conditioning unit  70  for supply power from electrical machine  68  to electrical machine  44 . A line  78  indicates an electrical coupling of electrical machine  44  to power conditioning unit  70  for supply power from electrical machine  68  to electrical machine  44 . In various embodiments, electrical machine  68  may be electrically coupled to electrical machine  44  and/or electrical machine  46 . In still other embodiments, electrical machine  68  may not be electrically coupled to either of electrical machine  44  and electrical machine  46 . In yet other embodiments, engine  20  may not include one or both of electrical machine  44  and electrical machine  46 . 
         [0023]    Reduction gearbox  66  is mechanically coupled to low pressure spool  26  via a shafting system  74 , and is operative to drive low pressure spool  26 . In one form, a clutch  76  is disposed between low pressure spool  26  and reduction gearbox  66 . In some embodiments, a transmission may be coupled between low pressure spool  26  and reduction gearbox  66 , e.g., in addition to or in place of clutch  76 . Clutch  76  is configured to mechanically engage and disengage APU  22  from low pressure spool  26  of the gas turbine engine  20 , e.g., in response to pilot commands or control inputs from an aircraft and/or engine controller. In one form, clutch  76  engages APU  22  to low pressure spool  26  for performing aircraft  10  taxi operation. In one form, clutch  76  disengages APU  22  from low pressure spool  26  during one or more of takeoff, cruise and landing modes. In other embodiments, clutch  76  may engage APU  22  with low pressure spool  26  during one or more of takeoff, cruise and landing modes, e.g., to provide supplemental power to low pressure spool  26 . Some embodiments may employ an overrunning (sprag) clutch between APU  22  and low pressure spool  26 . 
         [0024]    During operation, APU  22  generates an exhaust flow. In one form, APU  22  exhaust flow is directed to engine  20 , e.g., high pressure spool  24  (and/or low pressure spool  26 ) in order to warm engine  20  prior to engine start, which may reduce the amount of time it takes to start engine  20 . The APU  22  exhaust flow to engine  20  is illustrated as line  82  in  FIG. 3 . In various embodiments, valves and ducting (not shown) and/or other arrangements may be employed to direct the APU  22  exhaust flow to engine  20 . 
         [0025]    During operation, engine  20  generates a bleed flow, e.g., from high pressure spool  24 . The bleed flow is discharged from high pressure spool  24  through a bleed port  84 . In some embodiments, the bleed flow is directed into APU compressor  60 , indicated in  FIG. 3  by line  86 , which increases the efficiency of APU  22 , and which may reduce emissions from APU  22 . The bleed flow may be supplied via valves and ducting (not shown) and/or by other arrangements. The bleed flow may be supplied from high pressure spool  24  during aircraft  10  flight or ground operations, including prior to engine  20  start. 
         [0026]    In one form, APU  22  is configured to start or aid in the starting of engine  20  by supplying mechanical power to rotate low pressure spool  26  and/or by supplying electrical power to one or both of electrical machines  44  and  46  (in embodiments so equipped). In one form, engine  20  is started following the completion of taxiing operations of aircraft  10 . In other embodiments, engine  20  may be started during taxiing operations. 
         [0027]    Propulsion system  18  is configured to provide sufficient thrust to taxi aircraft  10  without starting engines  20 , which may result in fuel savings during taxi operations, since APU  22  is generally more efficient than engine  20  at thrust levels associated with taxiing aircraft  10 . Once aircraft  10  has reached a position where it is desirable to prepare for takeoff, engines  20  may be started, and declutched from APUs  22 . 
         [0028]    By employing APU  22  to provide rotational power to low pressure spool  26  and hence propulsor  28 , sufficient thrust may be provided for taxiing aircraft  10  without starting engines  20 , which may result in a fuel savings by the operator of aircraft  10 . In addition, in some embodiments, because APU  22  may be used to start engine  20 , the need for a pneumatic starter may be eliminated. 
         [0029]    Embodiments of the present invention include a propulsion system for a vehicle, comprising: a gas turbine engine having a spool configured to drive a propulsor, wherein the propulsor is configured to impart motion to the vehicle during normal vehicle moving operations; and an auxiliary power unit (APU) mechanically coupled to the spool, wherein the APU is operative to supply rotational power to spool. 
         [0030]    In a refinement, the propulsion system further comprises a gearbox mechanically disposed between the APU and the spool. 
         [0031]    In another refinement, the gearbox is configured to reduce an output speed of the APU. 
         [0032]    In yet another refinement, the APU is a second gas turbine engine. 
         [0033]    In still another refinement, the gas turbine engine includes an accessory gearbox; and wherein the APU is mechanically coupled to the accessory gearbox for driving the spool via the accessory gearbox. 
         [0034]    In yet still another refinement, the vehicle is an air vehicle. 
         [0035]    In a further refinement, the APU generates an exhaust, and the exhaust is supplied to the gas turbine engine to warm up the gas turbine engine prior to engine start. 
         [0036]    In a yet further refinement, the propulsion system further comprises a clutch mechanically coupled between the APU and the gas turbine engine, wherein the clutch is configured to mechanically disengage the APU from the spool. 
         [0037]    In a still further refinement, the APU includes an APU intake; wherein the gas turbine engine generates a bleed air flow; and wherein the bleed air flow is supplied to the APU intake. 
         [0038]    In a yet still further refinement, the propulsion system further comprises a generator coupled to the APU, wherein the generator is configured to supply electrical power to the vehicle when the gas turbine engine is not running. 
         [0039]    In another further refinement, the APU is configured to start the gas turbine engine by supplying mechanical power to rotate the spool. 
         [0040]    In yet another further refinement, the gas turbine engine is a turbofan engine, and the propulsor is a turbofan of the turbofan engine. 
         [0041]    Embodiments of the present invention include a vehicle, comprising: a cabin; a propulsion system, including: a propulsor configured to impart motion to the cabin, a gas turbine engine having a spool, wherein the spool is operative to drive the propulsor; and wherein the gas turbine engine is coupled at least indirectly to the cabin; an auxiliary power unit (APU) operative to supply mechanical power to the gas turbine engine via a reduction gearbox; and a shafting system mechanically coupling the spool to the reduction gearbox, wherein the APU is operative to supply rotational power to the spool via the shafting system and reduction gearbox. 
         [0042]    In a refinement, the vehicle further comprises a gearbox mechanically coupled between the APU and the spool. 
         [0043]    In another refinement, the power mechanically transferred from the APU to the gas turbine engine is configured to supply thrust sufficient for imparting motion to the vehicle. 
         [0044]    In yet another refinement, the vehicle is an air vehicle. 
         [0045]    In still another refinement, the gas turbine engine is a turbofan engine, and wherein the propulsor is a turbofan of the turbofan engine. 
         [0046]    Embodiments of the present invention include a system, comprising: a gas turbine engine having a spool is operative to drive a propulsor; and means for supplying mechanical power to the spool, wherein the means for supplying mechanical power is operative to supply rotational power to the spool. 
         [0047]    In a refinement, the means for supplying mechanical power includes an auxiliary power unit (APU). 
         [0048]    In another refinement, the APU is a second gas turbine engine. 
         [0049]    While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment(s), but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims, which scope is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures as permitted under the law. Furthermore it should be understood that while the use of the word preferable, preferably, or preferred in the description above indicates that feature so described may be more desirable, it nonetheless may not be necessary and any embodiment lacking the same may be contemplated as within the scope of the invention, that scope being defined by the claims that follow. In reading the claims it is intended that when words such as “a,” “an,” “at least one” and “at least a portion” are used, there is no intention to limit the claim to only one item unless specifically stated to the contrary in the claim. Further, when the language “at least a portion” and/or “a portion” is used the item may include a portion and/or the entire item unless specifically stated to the contrary.