Patent Publication Number: US-2020277874-A1

Title: Aircraft propulsion system having hybrid-electric powerplant and combustion powerplant

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of and priority to U.S. Provisional Patent Application No. 62/812,348, filed Mar. 1, 2019, and U.S. Provisional Patent Application No. 62/821,367, filed Mar. 20, 2019, the disclosures of each of which are hereby incorporated by reference in their entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The subject invention is directed to an aircraft propulsion system having two different types of powerplants, and more particularly, to a commercial passenger aircraft having a propulsion system that includes a gas turbine turboprop for driving one air mover and a hybrid-electric powerplant for driving another air mover. 
     2. Description of Related Art 
     The level of air traffic continues to increase worldwide, leading to increased fuel consumption and air pollution. Consequently, efforts are underway to make aircraft more environmentally compatible through the use of specific types of fuel and/or by reducing fuel consumption through the use of more efficient drive systems. 
     For example, aircraft having mixed drive systems that include a combination of various types of engines are known for reducing pollutants and increasing efficiency. Some current combinations include reciprocating engines and jet engines, reciprocating engines and rocket engines, jet engines and rocket engines, or turbojet engines and ramjet engines. 
     While these mixed drive systems are useful, they are not readily adaptable for use on commercial passenger aircraft. However, hybrid-electric propulsion systems that provide power through a combustion engine and an electric motor are indeed adaptable for use with commercial passenger aircraft and can provide efficiency benefits including reduced fuel consumption. The subject invention is directed to an aircraft having such a propulsion system. 
     SUMMARY OF THE DISCLOSURE 
     The subject invention is directed to a new and useful aircraft propulsion system having dual powerplants. The propulsion system includes a combustion powerplant and a hybrid-electric powerplant. The combustion powerplant delivers power to a first air mover for propelling the aircraft and the hybrid-electric powerplant delivers power to a second air mover for propelling the aircraft. 
     Preferably, the combustion powerplant includes a gas turbine turboprop engine, and the hybrid-electric powerplant includes a heat engine and an electric motor. The heat engine and the electric motor of the hybrid-electric powerplant can be arranged in either a parallel drive configuration or in an in-line drive configuration. The power delivery from the hybrid-electric powerplant can be about evenly split between the heat engine and the electric motor, or the power delivery from the hybrid-electric powerplant can be proportionally split between the heat engine and the electric motor. 
     It is envisioned that the heat engine of the hybrid-electric powerplant could be a rotary engine or a reciprocating engine of any fuel type with a configuration of turbomachinery elements, selected from a group consisting of a turbocharger, turbo-supercharger, or supercharger and exhaust recovery turbo compounding, which is mechanically, electrically, hydraulically or pneumatically driven. 
     A battery system provides energy to the electric motor of the hybrid-electric powerplant, and it is envisioned that the battery system could be located within the fuselage of the aircraft and/or within the wings of the aircraft or in any other location providing the required installation space and adjacency of the used electric power. 
     The subject invention is also directed to a new and useful commercial passenger aircraft that has a propulsion system with dual powerplants, which include a combustion powerplant associated with a first wing of the aircraft that delivers power to a first air mover for propelling the aircraft, and a hybrid-electric powerplant associated with a second wing of the aircraft that delivers power to a second air mover for propelling the aircraft. Preferably, the combustion powerplant includes a gas turbine turboprop engine and the hybrid-electric powerplant includes a heat engine and an electric motor that are arranged in either a parallel drive configuration or in an in-line drive configuration. The commercial passenger aircraft of the subject invention is the result of a modification to an existing aircraft having dual combustion powerplants, wherein a turboprop engine is associated with the left and right wings of the aircraft. By replacing the combustion powerplant associated with the right wing of the aircraft with a hybrid-electric powerplant that includes an electric motor and a heat engine, fuel consumption will be reduced. 
     The subject invention is also directed to a method of retrofitting an aircraft having a propulsion system with dual combustion powerplants, which includes the steps of removing at least a combustion powerplant from the aircraft, and then replacing the combustion powerplant that has been removed from the aircraft with a hybrid-electric powerplant, such that the aircraft has a combustion powerplant associated with one wing and a hybrid-electric powerplant associated with the other wing. 
     The subject invention is also directed to a method of retrofitting an aircraft having a propulsion system with combustion powerplants, which includes the steps of removing the existing combustion powerplants from the aircraft, and installing hybrid-electric powerplants on the aircraft, to improve the fuel efficiency of the propulsion system. 
     These and other features of the aircraft propulsion system of the subject invention will become more readily apparent to those having ordinary skill in the art to which the subject invention appertains from the detailed description of the preferred embodiments taken in conjunction with the following brief description of the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       So that those having ordinary skill in the art will readily understand how to make and use the subject invention without undue experimentation, preferred embodiments thereof will be described in detail herein below with reference to the figures wherein: 
         FIG. 1  is a top plan view of a commercial passenger aircraft having a propulsion system configured in accordance with a preferred embodiment of the subject invention, which includes a combustion powerplant associated with the left wing of the aircraft and a hybrid-electric powerplant associated with the right wing of the aircraft; 
         FIG. 2  is a front elevational view of the aircraft illustrated in  FIG. 1 ; 
         FIG. 3  is a left side front elevational view of the aircraft illustrated in  FIG. 1 ; and 
         FIG. 4  is a schematic representation of the propulsion system of the subject invention, which includes a combustion powerplant having a gas turbine engine and a hybrid-electric powerplant having an electric motor (eM) and a heat engine or motor (hM). 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to the drawings wherein like reference numeral identify similar structure or features of the subject invention, there is illustrated in  FIGS. 1 through 3  a commercial passenger aircraft  10  having a propulsion system that is configured in accordance with a preferred embodiment of the subject invention. 
     The aircraft  10  includes a fuselage  12  designed to carry passengers, a left wing  14  and a right wing  24 . The left wing  14  supports a first engine nacelle  16  for housing a combustion powerplant that delivers power to a first air mover or a propeller  18  to propel the aircraft  10 . The right wing  24  supports a second engine nacelle  26  for housing a hybrid-electric powerplant that delivers power to a second air mover or a propeller  28  to propel the aircraft  10 . 
     The propulsion system of aircraft  10  is the result of a modification to an existing aircraft propulsion system having dual combustion powerplants, wherein a gas turbine turboprop engine was associated with both the left wing  14  of the aircraft  10  and the right wing  24  of the aircraft  10 . As described in more detail below, by replacing the combustion powerplant associated with the right wing  24  of the aircraft  10  with a hybrid-electric powerplant, fuel consumption by the propulsion system of the aircraft  10  is demonstrably reduced. 
       FIG. 4  illustrates the propulsion system of the subject invention, which is designated generally by reference numeral  100 . The propulsion system  100  includes a combustion powerplant  200  and a hybrid-electric powerplant  300 . The combustion powerplant  200  is located in the nacelle  16  on the left wing  14  of the aircraft  10  and it includes a conventional heat engine, such as a gas turbine turboprop engine  212  or the like. 
     For example, the combustion powerplant could include a PW  120  turboprop engine manufactured by Pratt &amp; Whitney Canada, for delivering power to an air mover or propeller  225 , as in the case of a DHC-8 or Dash 8 series aircraft. A turboprop engine, such as a PW  120  turboprop engine, is a variant of a jet engine that has been optimized to drive a propeller. It incorporates a compressor, combustor and turbine within the gas generator of the engine. An additional turbine drives a power shaft and a reduction gearbox to drive the propeller. 
     A Hydro-mechanical Fuel Control Unit (HMU)  214 , which operates in conjunction with an electronic control unit, schedules fuel flow to the turboprop engine  212  in response to control input from the pilot by way of a Power Lever Angle (PLA) throttle  216  or a similar electro-mechanical controller located on the flight deck of the aircraft  10 . The combustion powerplant  200  further includes a Propeller Control Unit (PCU)  218  that receives input from the pilot by way of a Condition Lever Angle (CLA) throttle  220  or a similar electro-mechanical controller located on the flight deck of the aircraft  10 . 
     The CLA throttle  220  controls such functions as fuel cut-off, propeller feathering, propeller un-feathering, low idle/high idle selection, and propeller speed control. The condition lever may have two or more detents corresponding to specific RPM settings (i.e. takeoff, climb and cruise settings) or the lever may allow setting the propeller RPM to any value within an allowable range. 
     The hybrid-electric powerplant  300  of propulsion system  100  has two power lanes that deliver power to an air mover or propeller  325 . One power lane includes an electric motor (eM)  310  and the other power lane includes a heat engine (hM)  312 . The electric motor  310  and the heat engine  312  of the hybrid-electric powerplant  300  can be arranged in a parallel drive configuration or an in line drive configuration, depending upon the application. Power can be evenly split between the electric motor  310  and the heat engine  312  (i.e., a split of 50% electric motor power and 50% heat engine power), or power can be divided proportionally between the electric motor  310  and the heat engine  312  (e.g., any split from 10% electric motor power to 90% heat engine power or vice versa). 
     It is envisioned that the electric motor  310  would be designed to output up to 1 MW or more of shaft power to propeller  325 , with an output shaft speed of 12,000 RPM, or at any speed for the best combination of power density, heat management and efficiency. The electric motor  310  could include distributed winding or concentrated windings. 
     It is also envisioned that battery system would provide energy to the electric motor  312  of the hybrid-electric powerplant  300 . The battery system could be located within the fuselage  12  of the aircraft  10  and/or within the wings  14 ,  24  of the aircraft  10 , or in any other optimum location for space availability and proximity of use. 
     It is further envisioned that the heat engine  312  of the hybrid-electric powerplant  300  could be a heat engine of any type, e.g., a gas turbine, spark ignited, diesel, rotary or reciprocating engine of any fuel type with a configuration of turbomachinery elements, selected from a group consisting of a turbocharger, turbo-supercharger, or supercharger and exhaust recovery turbo compounding, which is mechanically, electrically, hydraulically or pneumatically driven. An example of a rotary engine suitable for this application is disclosed in U.S. Pat. No. 10,145,291, the disclosure of which is herein incorporated by reference in its entirety. 
     The hybrid-electric powerplant  300  further includes a Motor Controller (MC)  314  and an Engine Control Unit (ECU)  315  which communicate with one another by way of communication Bus, such as a CAN Bus or similar communication network. The hybrid electric powerplant  300  receives control input from the pilot by way of a Power Lever Angle (PLA) throttle  316  located on the flight deck of the aircraft  10 . The hybrid-electric powerplant  300  further includes a Propeller Control Unit (PCU)  318  that receives input from the pilot by way of a Condition Lever Angle (CLA) throttle  320  located on the flight deck of the aircraft  10 . 
     As described above, the propulsion system of aircraft  10  is the result of a modification to an existing aircraft propulsion system having dual combustion powerplants. Thus, the subject invention is also directed to a method of retrofitting an aircraft having a propulsion system with dual combustion powerplants. 
     The method involves the steps of removing one of the combustion powerplants  200  from the aircraft  10 , and then replacing the combustion powerplant  200  that has been removed from the aircraft  10  with a hybrid-electric powerplant  300 , such that the aircraft  10  has a combustion powerplant  200  associated with one wing and a hybrid-electric powerplant  300  associated with the other wing. 
     The subject invention is also directed to a method of retrofitting an aircraft  10  having a propulsion system with two combustion powerplants  200 , which includes the steps of removing the existing combustion powerplants  200  from the aircraft  10 , and installing two hybrid-electric powerplants  300  on the aircraft  10 , to improve the fuel efficiency of the propulsion system. 
     While the systems and methods of the subject invention has been described with reference to preferred embodiments, those skilled in the art will readily appreciate that changes and/or modifications may be made thereto without departing from the spirit or scope of the subject disclosure.