Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B64—AIRCRAFT; AVIATION; COSMONAUTICS
  • B64C—AEROPLANES; HELICOPTERS
  • B64C25/00—Alighting gear
  • B64C25/32—Alighting gear characterised by elements which contact the ground or similar surface 
  • B64C25/405—Powered wheels, e.g. for taxing
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
  • Y02T50/00—Aeronautics or air transport
  • Y02T50/80—Energy efficient operational measures, e.g. ground operations or mission management

Definitions

• the present invention belongs to the field of aircraft propulsion.
• the invention relates to an aircraft comprising a device ensuring the propulsion of the aircraft plane when it is on the ground during the take-off phases and incidentally the taxiing phases during its ground circulation.
• the invention also relates to a method of implementing the device.
• the movement on the ground excluding certain movements made with a towing vehicle, is generally performed by rolling on wheels of a landing gear under the action of the propulsion motors of the aircraft. 'plane.
• the engines of the aircraft, reactors, turboprop turbines or piston engines are therefore started and the force generated by reaction or propellers is modulated by the orders of the pilot to move the aircraft on its wheels.
• the engines are quickly brought to their nominal takeoff power so as to accelerate the aircraft on the runway, from a speed of almost zero, to the speed necessary to achieve the flight.
• the engines When traveling on the ground the engines are also used with more or less power in combination with the brakes to regulate the movement on taxiways and other traffic areas.
• This procedure is used in the case of civil aircraft because it has the advantage of being simple and universal to implement and allows the aircraft to be autonomous.
• the engines have a poor performance that leads to a significant consumption of fuel in the mission of the aircraft and emit pollutants due to the combustion residues emitted at ground level and imperfect combustion of fuels.
• the sound level produced on the ground in these conditions affects the residents of airports.
• wheel motors powered by on-board power generators for example electric or hydraulic motors.
• propulsion engines Although limiting the use of propulsion engines, these engines require energy that is provided by propulsion engines operating at least idle or by an auxiliary power unit (APU). The interest of such a solution is therefore limited, especially as the mass and complexity introduced into the landing gear penalize the aircraft elsewhere.
• APU auxiliary power unit
• the present invention provides an aircraft comprising a take-off assistance device that reduces the current constraints related to the use of only the propulsion engines during takeoff.
• the aircraft of the invention conventionally comprises one or more propulsion engines and a landing gear comprising wheels arranged on undercarriages.
• the aircraft also comprises at least one wheel motor arranged to rotate at least one wheel of an undercarriage of a landing gear of the aircraft, and the take-off assistance device comprises at least one main computer.
• command and control system that supervises the operation of the propulsion engine (s) and the wheel motor (s) while the airplane is taxiing during a take-off phase, the wheel motor (s) being an electric motor.
• the aircraft comprises an electrical energy storage system for powering the wheel motor or motors, said energy storage system comprising in particular a set of supercapacitors and or electric storage batteries and or battery cells.
• fuel capable of accumulating energy at least equal to the energy required to accelerate the aircraft at taxi from a substantially zero speed at one end of the runway to a velocity Vel less than the take-off speed of the aircraft. airplane when the wheels leave the ground.
• a first quantity of energy is thus provided to the aircraft by means of the wheels and the wheel motors, resulting in a running speed on the take-off runway having the effect of limiting the energy input by propulsion engines until take-off in a low-speed range where aircraft propulsion engine efficiencies are the worst.
• the main computer monitors the operation of the propulsion engine (s) and / or wheel motor (s) through secondary computers of each of the propulsion engines and / or wheel motors.
• a secondary calculator may not concern only one propulsion motor or wheels, for example a FADEC of a propulsion reactor, or may concern two or more propulsion engines or wheels, for example a secondary calculator for several engines of road wheels. an even undercarriage or for example a secondary computer addressing all the wheel motors.
• the landing gear comprises at least two main undercarriages and an undercarriage and at least one wheel of each of the main undercarriages is driven by a wheel motor.
• the propulsion engines are electric motors powered by an on-board storage and / or power generation system and the recharging means for supercapacitors and / or electric storage batteries and or fuel cells. are connected to the on-board storage and / or power generation system that powers the propulsion engines to supply power to supercapacitors and / or electric storage batteries and or fuel cells.
• the aircraft includes a single thrust or power control in the cockpit that determines a desired acceleration order transmitted to the main computer.
• This provides a simple means of thrust control during taxiing that allows the pilot to perform takeoff acceleration in a conventional manner by acting on the single thrust or thrust control without having to worry about it. different modes of propulsion and their transition.
• the invention also relates to a method of accelerating the take-off of an airplane during a take-off taxiing phase, said aircraft comprising at least one propulsion engine and comprising at least one wheel motor, electrically powered with energy, arranged to rotating at least one wheel of an undercarriage of a landing gear of the aircraft.
• the take-off acceleration during the taxiing phase comprises a first step E during which the aircraft is accelerated mainly by the wheel motor (s), then a second step H during which the airplane is accelerated jointly by the or the wheel motors and by the propulsion engine or engines, then a third step P during which the aircraft is accelerated mainly by the propulsion engine or engines.
• the transition from the first step E to the second step H is characterized by a first speed VeO and the transition from the second step H to the third step P is characterized by a second velocity Vel greater than the velocity VeO, the second velocity Vel resulting operating limits of the at least one wheel motor and an electrical energy storage system electrically supplying the one or more wheel motors, the first speed VeO being calculated by the main computer according to an estimated acceleration between the two speeds VeO and Vel, dependent on the thrust produced by the wheel motors combined with that of the propulsion engines, and as a function of a time of establishment of the thrust or the power of a take-off speed of the at least one propulsion engine.
• the speed of the propulsion motor or engines is continuously controlled so that a resulting thrust produced or the propulsion engines is substantially zero or weakly positive.
• the propulsion engines create an aerodynamic drag which would have the effect of reducing the acceleration, of increasing the quantity of electrical energy to reach the speed of desired transition and increase the runway length required for take-off.
• the wheel motor (s) are decoupled, for example by a controlled clutch / clutch system or by a freewheel operation when the wheels are rotated on the ground at a speed greater than that of the motors. of wheels or wheels which they rotate during the third step P, avoiding that the motors are driven empty by the speed of the wheels, in particular if it is desirable that the speed of rotation of the motors of wheels is limited or to prevent said wheel motors from taking up energy provided by the propulsion engines.
• the wheel motor or motors are used as an electric energy generator in the event of deceleration of the aircraft during taxiing, for example due to an interruption in take-off or during a landing.
• Figure 1 an aircraft according to the invention with a block diagram of the take-off assistance device
• Figure 2 an illustration of the various steps of takeoff, according to the invention, an aircraft on a track.
• Figure 2 an illustration of the various steps of takeoff, according to the invention, an aircraft on a track.
• the different elements of the same drawing or on the different drawings are not necessarily represented on the same scale.
• FIG. 1 represents a view of a plane 100 on the ground and schematically illustrating the various main components of the invention.
• the aircraft 100 comprises in known manner a landing gear, in the example shown two main landing gear 10a fixed to the wings of the aircraft symmetrically and a front landing gear 10b, in a conventional arrangement.
• the number and arrangement of landing gear landing gears are however not imposed and may be different from the illustrated form.
• the aircraft 100 comprises, also in known manner, two propulsion engines 11, here double-flow reactors, attached to the wings.
• the number and the arrangement of the engines are also not imposed in the context of the invention, the aircraft comprising at least one engine.
• the engine (s) can also be fixed other than under the wing, for example attached to the fuselage.
• the aircraft comprises a take-off assistance device 20 comprising:
• At least one wheel motor 12 mechanically coupled to provide a rotational drive of at least one wheel 13 of the landing gear, said at least one wheel motor being an electric motor;
• an electrical energy storage system 21 for supplying the wheel motor (s) 12;
• At least one control and control main computer 22 which supervises the operation of the propulsion engine (s) 11 and the wheel motor (s) 12.
• At least one wheel of each of the main undercarriages 10a is coupled, at least in certain take-off steps, to a wheel motor 12 of said undercarriage.
• Each wheel motor 12 is dimensioned in power so that the set of wheel motors is able to accelerate the aircraft 100 in an initial takeoff taxiing step with an acceleration of the order of 1 m / s 2 or plus, ideally an acceleration close to an acceleration that would be obtained with the only propulsion engines 11 in standard condition (at sea level and ISA temperature).
• each wheel motor comprises a disengaging device, not shown, which, depending on the driving phases, allows coupling or decoupling a wheel motor from the wheel.
• the main computer 22 for example a digital technology calculator having a processor and memory units for storing instructions and executing a program, receives data relating to the operation of each of the propulsion engines 11 and wheel motors 12 produced by a calculator secondary 23a of each of the propulsion motors 11 and or a secondary computer 23b of each of the wheel motors 12 and generates commands, for example a controlled thrust, or a wheel rotation speed controlled, generally a control relating to the power to be delivered by each motor and which are transmitted to the secondary computer of the engine considered.
• the secondary computer 23a is for example in the case of a reactor or a turboprop engine designated FADEC (Full Authority Digital Engine Control) on current aircraft engines.
• FADEC Full Authority Digital Engine Control
• all or part of the functions that can be performed in the secondary computers 23a, 23b are provided directly by the main computer 22 taking into account a complexity of the functions provided and design constraints in terms of security.
• each propulsion motor 11 and each wheel motor 12 comprises a secondary computer 23a, 23b.
• the main computer 22 also includes control signal inputs corresponding to pilot commands issued from pilot commands or orders developed by an autopilot from equipment 14 dedicated to piloting the aircraft 100 as well as corresponding data signals. to information on the operating conditions of the aircraft such as for example a measured speed provided for example by a central air and inertial, in particular a true speed Vv of the aircraft relative to the ground and an airspeed Vcas (Calibrated Air Speed) of the aircraft with respect to the air, and also reference speeds functions of the take-off conditions such that, in the case of a multi-engine airplane, a decision speed VI beyond which the takeoff must not be interrupted or a rotation speed Vr.
• a measured speed provided for example by a central air and inertial
• Vv true speed
• Vcas librated Air Speed
• the electrical energy storage system 21 necessary for the operation of the wheel motors 12 is sized to store an amount of electrical energy at least equal to that to be delivered in mechanical form by all the wheel motors during a phase. of takeoff of the aircraft and the duration during which said wheel motors will participate in the acceleration of the aircraft 100 on the track, that is to say with sufficient power to satisfy this condition.
• the energy delivered by the wheel motors 12 is at most equal, in practice less, to the total energy acquired by the aircraft 100 during the take-off period. This limit is introduced naturally because the wheels 13 can no longer provide energy after the aircraft has left the ground.
• propulsion engines 11 actually provide the thrust required for the flight when the wheels of the aircraft leave the ground.
• the wheel motors 12 are advantageously sized to provide energy to the aircraft only in an initial phase of takeoff, thus limiting the constraints of the electrical energy storage system and the constraints of rotational speeds and power of the wheel motors 12, propulsion engines taking the relay when the speed of the aircraft on the ground reaches a transition speed Vtl.
• the electrical energy storage system comprises alone or in combination: electric storage batteries, fuel cells, a set of supercapacitors 24. These components have a storage capacity of electrical energy and are able to provide the electric power required by the wheel motors.
• the electrical energy storage system 21 further comprises means 25 for recharging the set of supercapacitors 24 and or batteries of electric accumulators.
• the charging means 25 comprise as energy generator for example conventional electric storage batteries, or fuel cells, or an auxiliary power unit with thermal engine (APU). These recharging means 25 do not need to deliver the power necessary for the operation of the wheel motors 12 but are able to deliver over a long enough period the energy required to recharge the supercapacitors 24 and or electric storage batteries having capabilities and performance.
• APU auxiliary power unit with thermal engine
• the recharging means 25 comprise connection means 26 to ground energy sources, not shown, which make it possible to recharge the supercapacitors 24 and or electric storage batteries, and or the fuel cells, before a flight without using the energy stored on board the aircraft 100 by the charging means 25.
• the recharging means 25 use a braking energy during a deceleration phase of the aircraft, in particular during an interrupted landing or take-off, to recharge the supercapacitors 24.
• the braking energy is taken from the kinetic energy of the aircraft 100 by the wheel motors 12 operating in an electric generator mode.
• the take-off comprises three main stages, as shown in FIG. 2, which presents an aircraft in taxi phase. take-off on a runway on a take-off flight path 31.
• a first step E the aircraft 100 is at a first end of a take-off runway, at zero or low speed, the supercapacitors 24 and / or electric storage batteries having been previously loaded by the recharging means 25, either with an energy generator embedded in the aircraft or by a source of energy external to the aircraft.
• Propulsion engines 11, if they have not been started previously are started and maintained at an idle ground speed before the start of acceleration on the runway 30 takeoff.
• the prior start of the propulsion engines 11 is a priori necessary for safety reasons in order to check their correct operation before takeoff and to avoid aerodynamic drag when the speed of the aircraft is increased during the first step E as described herein. -after.
• said main computer controls the wheel motors 12 to produce an acceleration of the aircraft 100 on the runway 30.
• a limited acceleration can be controlled by the main computer 22, in a general case it will be sought the maximum acceleration compatible with the capacities of the wheel motors 12, the energy storage system 21 and wheel adhesion 13 on the track, adhesion capacity which can be limited and binding in the event of a contaminated runway.
• the main computer 22 simultaneously acts on the power of the propulsion engines 11, initially at idle, so as to maintain a resultant thrust, absolute thrust decreased aerodynamic drag, said engines of substantially zero or weakly positive propulsion , depending on the speed reached by the aircraft 100 at each moment.
• This control of the main computer 22 has the effect of preventing the propulsion motors 11 from causing drag due to the winding operation of the propellers or the reactor fans. Such drag would cause an additional energy requirement for the wheel motors 12 to reach a given speed and would go in the opposite direction of maximum acceleration for takeoff and a desired energy saving.
• This first step is continued until a speed of the aircraft VeO.
• a second step H is engaged in which the propulsion of the aircraft 100, still accelerating and rolling on the track 100, is carried out in a hybrid manner by a joint action of the wheel motors 12 and engines Propulsion 11.
• the main computer 22 controls, at the passage of the speed VeO, the takeoff thrust of the propulsion engines 11 while continuing to control the wheel motors 12 so that the latter continue to provide an acceleration energy .
• the second step H ends when the aircraft 100 still traveling on the runway 30 reaches a speed Vel.
• the speed Vel corresponds to a limitation of the wheel motors 12 when the latter are no longer able to produce an acceleration due in particular to the speed of rotation of the wheels and the required power.
• the propulsion engines 11 produce, when the speed Vel is reached at the end of the step H, the take-off thrust controlled by the main computer. .
• propulsion engines in particular the turbines of reactors or turboprops, require a duration dt, variable, revving up to several seconds due to an inertia of the rotating parts and control constraints .
• the speed VeO is calculated by the main computer 22 according to the particular conditions takeoff, in particular the temperature and altitude of the runway, which make it possible to determine a duration necessary for the propulsion engines 11 to reach the take-off thrust and as a function of an estimated acceleration during said duration dt.
• a third step P is engaged in which the aircraft is accelerated by the thrust produced by the propulsion engines 11.
• the third step P ends with the end of taxiing of the aircraft 100 on the runway 30 of takeoff, that is to say when the wheels of the aircraft leave the ground after the rotation of the aircraft at the speed Vr.
• the wheel motors 12 no longer provide power to the wheels and the aircraft. They are in this stage driven in free rotation without absorbing energy, except for possible friction, which will be minimized by conventional solutions, or mechanically decoupled wheels 13.
• the wheels driven by wheel motors in the first and second steps are mechanically decoupled wheel motors, for example by a controlled clutch / clutch system or for example by a freewheel system, for example ratchets, which allows the wheel to have a speed greater than the rotational speed at which it would be driven by the wheel motor without causing the motor to rotate.
• the aircraft 100 continues its flight phase conventionally after rotating at the speed Vr.
• the aircraft 100 comprising the take-off device 20 described is capable of variants within the reach of those skilled in the art.
• the various means of the device will advantageously be adapted to the technological choices of the aircraft 100 to which said device is integrated.
• the electrical energy storage system 21 will be arranged to use, alone or in combination with other sources, storage and / or power generation sources of the propulsion system.
• the wheels coupled to wheel motors will be wheels supporting a significant weight of the aircraft, for example the wheels of the main landing gear, without it being excluded to also couple wheels auxiliary landing gear.
• a wheel motor can also drive several wheels of the same undercarriage or one.
• the main computer 22 receives a takeoff acceleration command from a single command of a pilot of the aircraft so that the different steps E, H and P of the takeoff acceleration corresponding to the successive modes of acceleration by the wheel motors 12 and the propulsion motors 11 need not be taken into account by the pilot in his take-off conduct.
• the take-off assistance device 20 is also used to carry out the taxiing of the aircraft during its movements on the ground on the taxiways to get from a parking lot to the start of the take-off runway. and or to get from the runway to a parking lot after a landing.
• the wheel motors are not necessarily powered by supercapacitors and / or electric storage batteries and can be powered by other sources of power. energy storage means of charging or the aircraft.
• the take-off aid device and its method of implementation allow to limit the operation of the propulsion engines during a significant portion of the taxiing of the aircraft.
• the power provided by the wheel motors is independent of the altitude of the ground unlike the case of thermal engines, turbines or piston engines, whose thrust or power varies in the same direction as the atmospheric pressure decreases as altitude increases.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Aviation & Aerospace Engineering (AREA)
• Electric Propulsion And Braking For Vehicles (AREA)
• Hybrid Electric Vehicles (AREA)

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• 2013
  • 2013-06-14 FR FR1355583A patent/FR3006991B1/fr not_active Expired - Fee Related
• 2014
  • 2014-06-13 EP EP14729688.3A patent/EP3007972A1/de not_active Withdrawn
  • 2014-06-13 WO PCT/EP2014/062421 patent/WO2014198920A1/fr active Application Filing

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