WO2010046938A1

WO2010046938A1 - Electric engine for aircraft

Info

Publication number: WO2010046938A1
Application number: PCT/IT2008/000663
Authority: WO
Inventors: Marco Marotta
Original assignee: Marco Marotta
Priority date: 2008-10-24
Filing date: 2008-10-24
Publication date: 2010-04-29
Also published as: EP2346735A1

Abstract

The present invention comprises a device to generate the thrust of an aircraft in general, as for example airplanes or helicopters, and comprising means (1) operatively connected to at least a propeller (2) that generates the thrust. According to the present invention, the above means comprise in combination at least an electric engine (5; 205) connected to power supply means (7) to feed the engine with current and allow its functioning.

Description

ELECTRIC ENGINE FOR AIRCRAFT

Technical Field

The present invention refers to the technical field of aircraft in general as airplanes, helicopters, amphibian and similar. In particular it refers to a new type of propulsive apparatus prevalently, but not exclusively, for vehicles of Medium and Light type.

State of the Art

Nowadays are know many combustion propulsive system for aircrafts in general that allow to drive the vehicle in a sufficient way to realize the lift and maintain it in flight. The different types commonly used change both in the dimensions and in the planning and functioning concept. In this way are obtained engines with the most diverse performances and each of the typically suitable to vehicles of particular dimensions and specific routes. Are then distinguished engines able to drive small touring vehicles or vehicles where it is sufficient to reach a low or medium subsonic speed and engines that realize a thrust many times higher than the threshold of the sound. These last types of engines are for example commonly used in the vehicles for aerial combat.

For example, the common Turbofans commonly used on the big and medium jumbos of the civil aviation, generate a thrust of fluid mass in the direction opposite to the one of the advancement of the aircraft determining this way the advancement of the same aircraft. In particular, the air gets pumped frontally by the engine and enters in a compressor that takes it to the wanted pressure. Afterwards, it enters the combustion chamber where is mixed to the atomised fuel and the combustion takes place with an increasing in the temperature and pressure. The mass of the burnt gasses enters into a turbine where it is expanded. At last, at a pressure greater that the one of the outside, the air and the products of the combustion complete the expansion in the nozzles and are sent off toward the outside generating the required thrust. As mentioned, this type of thrust is great and allows to reach speeds close to the sound barrier in the case of big jumbos of the civil aviation and speed above the sound for the war fighters.

On the other hand, in the case of aircraft with small or medium dimensions (as for example small touring aircrafts or freight aircrafts with medium dimensions or also helicopters) it is commonly used the propeller drive. Obviously the thrust is substantially lower than the one previously described and thus also the obtained results.

In this case, for example, a simple explosion engine can activate a propeller that thrust the aircraft. A rotating shaft is thus keyed to the propeller and drag this last one to spin causing the advancement.

In all the analysed cases the engines, as the combustion chambers in general, need fuel in order to function. At this point it is clear which are the substantial inconvenient of the present prior art. The cost of fuel undergoes to continuous push-ups such to make it almost prohibit the flight costs. The air companies have to support too much elevated fuel costs and are then forced to regain the costs raising substantially the cost of the ticket. Everything is reflected negatively on the final consumer who will be forced to spend a lot more to cover his flight routes or to renounce to the "air" transportation mean. In the most extreme cases, the small companies, as for example those specific private or for tourism, are forced to declare bankruptcy being not able to sustain such costs and be affected seriously by the decrease of potential clients.

Another inconvenient is represented by the pollution. Indeed, the commonly used fuel is highly pollutant, especially the one emitted by the airplanes, given the big quantities required to cover the flight routes. Moreover, both the problem of fuel cost and the problem of pollution is more pointed out by the nowadays evolution of the land type public transportation means (as for example the high speed trains) . Indeed, these are able to be everyday more competitive with the air transportation means both in terms of time required to cover the travel routes, and also in terms of costs and pollution. At last, but not less important, the combustion engine commonly used in the aeronautic field are highly pollutant also from the point of view of sound. All these not only creates big inconvenient for the houses that are close to the airports, but also for the same airports which are obliged to use very expansive sound proofing systems .

Disclosure of invention

It is therefore the aim of the present invention to give a new type of propulsion that resolves all the above mentioned inconvenient.

In particular, it is the aim of the present invention to give a new type of propulsion that allows to realize a remarkable fuel saving dropping the costs. It is also the aim of the present invention to give a propulsion for aircrafts that allows to drop down remarkably both the pollution rate in terms of sound and toxic gases released in the atmosphere.

These and other aims are obtained through the present device to generate the thrust of an aircraft in general and comprising means (1) operatively connected to at least a propeller (2), said means determining the rotation of the propeller to generate the thrust of the aircraft and characterized by the fact that the mentioned means (1) comprise in combination at least an electric engine (5; 205) connected to means of power supply (7), said power supply means supplying power to the engine to allow its functioning. Thus, it is clear how the use of an electric engine, in combination to appropriate means that feed it, allow to exceed all the inconvenient of the prior art, or rather of the use of explosion engines.

According to the different possibilities, the power supply means (7) could for example comprise at least a main battery (11), which stores the power and uses it to feed the operating engine.

Alternatively, it could be used at least an electric current generator (8; 208) AC/DC and/or DCW (9; 209) electrically connected straight to the engine. In this way, the current produced by the generator will not be stored by the batteries but will directly feed the engine. Another solution can on the other hand comprise a main battery (11) in combination to at least an electric current generator (8; 208) AC/DC and/or ACW (9; 209) .

According to this solution, both the generator and the battery will feed the engine.

Advantageously it is comprised a second spare battery

(12) electrically connected to the electric engine (5; 205) . It is clear how this is required for a flight safety, at least in a condition of breakdown of the main batteries .

Without moving apart from the present inventive concept, it could be comprised a main battery pack (11) and a second spare battery pack (12), increasing, in this manner, the autonomy of the aircraft and thus the maximum feasible distance.

Then with the aim to guarantee a minimum level of charge in the batteries, are comprised recharging means

(8, 10, 10', 17; 208) connected to at least the main battery (11) and/or to the second battery (12) to allow to feed them at least during the flight phase.

In this way, it is always possible to maintain constant or almost the level to recharge of the sames . The secondary battery could then work as real emergency batteries in the case of breakdown of the main ones.

Advantageously, the recharging means comprise the main current generator (8; 208) AC/DC, said generator being activated by the electric engine to produce current.

A second solution comprises also at least a solar collector (10) and/or aeolic devices (10') electronically connected to the batteries.

Obviously nothing forbids to use in combination the main current generator (8; 208) with the solar collector (10) or with the aeolic devices. This last ones result afterwards particularly convenient, as (through simple propellers) the use the passive dragging of the wind to activate common recharging generators. In the structural detail, with the aim to make the generator functional and to allow to it to produce current, the main generator AC/DC (8; 208) and the second generator ACW (9; 209) are keyed on a shaft (4; 204), while unhooking mechanical means allow to connect in an releasable manner the same main generator (8; 208) to the electric engine.

In this way, this last one is automatically activated by the engine and it is possible to release it when it is required. In particular, the unhooking mechanical means can be activated into a working position where they bind the generator to the shaft (4; 204) to make it rotate producing electric current that can be sent to the batteries and/or to the engine and a neutral position where the generator does not result integral to the shaft (4; 204) .

Advantageously, the electric engine (5; 205) is connected to the shaft (4; 204) through a gearbox (6; 206) , said box changing the number of revolutions in input to said shaft (4) .

In this way there is always a number of revolutions suitable to generate the thrust through the propeller. It is also structurally clear how the activation of the main generator is possible thanks to the keying of the engine to the shaft through said gearbox.

Moreover, the engine is connected in a releasable way to the main current generator ACW (9; 209), said ACW feeding the remaining utilities of the aircraft.

The lights and anti-freezing devices and similar can thus be fed through ACW.

Advantageously at least an inverter is interposed in the points of current input to the engine. In this way the current in input to the engine will be suitable for its correct functioning eliminating, moreover, potential current peaks when started.

The global number of electric engines connected to the single propeller is variable. In particular the solution "stand alone " comprises a single electric engine (5) .

Alternatively any number of engine could be used. In particular, results to be particularly advantageous a global number of electric engine (205) comprised between two and six.

In the generic case where the number of engine used is greater that one, the engine (205) are placed concentrically respect to the rotating shaft (204) of the propeller on a star type structure, while the gearboxes (206) connect the engine to the rotating shaft of the propeller. In all the described configurations is then comprised a second current generator (17) AC/DC mechanically connected to an APU, said APU activating the second generator to feed the batteries and/or engine (5; 205) .

In conclusion there could be two generators, and precisely a main (8; 208) and a second (17) eventually collaborating with each other. Also in this case are possible different combinations solutions. For example the main generator can be mechanically disconnected by the engine (5; 205) while the second generator results in function by means of the APU and electrically connected to the engine and to the batteries.. In this way the engine will rotate without having to provide the activation of the main generator (and therefore requesting a surplus of power) and, at the same time, will absorb current directly from the second generator activated by the APU or by the batteries fed by this last one. according to another possibility, the main generator results mechanically and/or electrically connected to the engine (5; 205) and the second generator disconnected from the APU and thus not activated. This result to be the most simple standard configuration, where the APU is simple placed to activate the secondary utilities of the engine, as in the prior art.

Finally it is possible a configuration where the main generator is electrically and/or mechanically connected to the engine and the second generator is also electrically connected to the engine and mechanically to the APU. In this way the engine will be assisted by both.

According to the present invention, it is also described an aircraft in general. As helicopters, airplanes and amphibian, comprising means (1) able to activate at least one propeller (2) to generate the thrust and characterized by the fact that said means comprise: - At least an electric engine (5; 205) connected mechanically and/or electrically to at least a main generator (AC/DC (8; 208) and/or ACW (9; 209), said electric engine driving into rotation the propeller and activating the generator to produce current; - At least a main battery (11) electrically connected to the engine (5; 205) and to the generator, said battery feeding the engine during its functioning and said generator recharging the battery.

Brief description of drawings

Further features and advantages according to the propulsive system, according to the invention, will be clearer with the description of one of its pattern realization that follows, made to illustrate but not limit, with reference to the annexed drawings, in which:

- Figure 1 described, both with a block diagram and a schematic perspective view, the technical solution according to the present invention;

- figure 2 describes schematically a first preferred configuration of the invention with an engine into stand alone condition and a wing section where are placed recharging batteries and solar collectors;

- figure 3 shows schematically a second preferred configuration of the invention with more engines applied to the rotating shaft of the propeller;

- figure 4 shows a complete block diagram according to the invention and a wing section with a possible positioning of the APU system;

- Figure 5 shows schematically a complex view of an aircraft on which is assembled the present propulsive device according to the invention.

Description of some chosen pattern realizations Figure 1, represents, according to the invention, a propeller device to generate the thrust (or anyway the traction in general) of an aircraft, as for example helicopters, airplanes or ultralights. In particular, it is represented a first preferred configuration of the invention, or rather a constructive solution with single engine called also "Stand alone". In this case, an engine pod 3, totally common, is required to cover and contain in its inside the entire propulsive apparatus of the aircraft. As known from the prior art, the room of the engine pod can be realized in different places of the aircraft and strictly dependent to the dimensions and characteristics of this last one. For example it is common a positioning underneath or above the wing and with the propeller in an advanced or back position. There will be distinguished in this manner thrusting type or traction type propellers. According to the aim of the present invention it is totally indifferent the positioning of the above mentioned means and the type of propeller used. the undertaken figure 1 thus represents, also through a block diagram, means 1 connected operatively to a propeller 2 to allow the drag into rotation and, in particular, are highlighted the power supply means that are required to maintain in function the driving engine 5 of the propeller. As described in a better constructive detail in figure 2, the engine pod 3 contains in its inside the means 1 connected operatively to a propeller 2. In particular the above mentioned means 1 comprise a shaft 4 that connect the single engine 5 to the propeller 2 to conduct it to rotate and generate thrust. A gearbox 6 is then keyed directly on the shaft 4 to allow to change opportunely the number of revolutions in output from the engine and in input on the same shaft. For this aim a belt 6' . Or equivalent devices, can be interposed between the shaft exiting from the engine and the same gearbox. In this way the propeller will rotate according to opportune rpm that can be changed by the pilot according to all the needs and flight conditions. Thus, according to the present invention, the utilized engine is an electric engine 5 placed in combination to the opportune power supply means 7 required to send current to feed it allowing it to run. In a total general manner, the above mentioned supply means can comprise any device suitable for the production function (8, 9, 10, 10', 17; 208, 209) and eventually store (11, 12) electric power that will be then sent to the engine 5 during its functioning.

As still described in figure 2, for such aim it is comprised a main battery pack 11 electrically connected to the engine. In a non limitative way, the main battery pack can be composed also by a sole battery with opportune dimensions (obviously this will exclusively depend on the length of the routes to which the specific aircraft is made for) . Moreover a secondary single or battery pack 12 will be required for an eventual spare. Still figure 2 represents a possible location of the battery packs. In particular an advantageous location could be in the wing section 13 commonly used, according to the prior art, to receive the fuel. The electric connection between batteries and engine (non shown in the figure) can happen through simple electric cables.

Obviously with the aim to maintain the opportune level of charge of the batteries it is required to comprise opportune recharging means. For this aim, a double current generator 8 (AC/DC generator) is mechanically keyed on the spin axis 4 of the propeller in combination to a generator 9 of ACW type and electrically connected both to the main and secondary batteries and to the same engine. Moreover, as represented in figure 2, solar collectors 10 are connected directly to the batteries with the aim of maintaining them always at opportune charging levels. Nothing would avoid to use, in combination with the solar collectors or even alone, aeolic devices 10' (commonly called RAT devices) . These consist in propellers placed in different useful position of the aircraft and connected to generators in general (for example on the front part of the aircraft or on the tail) . In this way, by using the relative dragging of the wind, they produce current similarly to the collectors. An APU device 16 (Alternative Power Unit) nowadays commonly used in all the aircrafts can then be integrated to what has been described above (look at figure 4) . As a matter of fact the APU can be assimilated to a small engine that is used for some utilities of the aircraft, as for example the hydraulic pumps and air conditioning feeding. In particular, according to the invention, the APU (usually placed in the tail section of the aircraft) can be connected to secondary AC/DC generators 17 to produce current to be sent directly to the electric engine and/or to the above mentioned batteries.

Moreover common Inverter are placed in all the points of input of the current into the engine in a way to convert the voltage input entering into the engine in a value adequate for , its functioning (look at the block diagram figure 4) .

' It is now briefly described the functioning principle of the device.

As described in figure 1 and figure 2, the electric engine is fed during the entire flight phase by means of power supply 7, or rather in normal conditions, by the main batteries. In this way the engine can continuously turn and control the rotation of the propeller. In particular, the rotation of the shaft 4 on which it is keyed the propeller causes the rotation of the double current generator 8 and the ACW current generator 9 which produce electric power. The main AC/DC generators 8 are thus electrically connected to the main and secondary batteries to recharge them and to the engine to eventually feed it. The ACW generator 9 feeds on the other hand all or many of the secondary utilities of the aircraft (as for example lights, Anti-Ice devices etc.) . In this way, during the normal functioning of the engine, the batteries feed the engine allowing to the propeller to turn. The generators, as already said, maintain a continuous level of charge both in the main batteries, and in the secondary- batteries. Thus, in case of emergency, the secondary batteries will always have a minimum level of charge guaranteed to allow at least the reaching of the closest airport along the route (Safety principle equivalent to the case of using fuel) .

Obviously, without any limitation, the number ans the types of generators could be any. For example it is possible to use a sole AC/DC generator able to produce alternate and direct electric power as represented in figure 2. In alternative, there can be used two different generators that make respectively spread alternate and direct current.

Moreover also the main AC/DC current generators are electrically connected directly to the engine being able to function, beyond the common recharging means, also as power supply means. This solution is usable both in the case of excess of power in the batteries and in the hypothesis of breakdown of all the batteries. In such case, the current obtained by the main generators is directly absorbed and conveyed to the engine (look at the electric connection in figure 2 in engine pod) . Alternatively it is also possible to comprise an electrical input coming in part from the batteries and in part from the generator. Beyond the common generator, the recharge of the batteries can be made exclusively or in combination to the solar collectors 10 and/or the aeolic devices 10' . In critical flight conditions where the engine absorbs a lot of power, it is possible to connect the secondary generators to the APU to make them turn and produce current to sent to the batteries and/or directly to the engine in combination to the main generators. As described, the main generators are directly keyed on the rotating shaft of the propeller and turn thanks to the action of the engine 5. This is translated into a waste of power of the engine spent to make them turn mechanically. Nothing would then avoid to comprise mechanical pull-off means of the main AC/DC generator 8 to be able to idle it respect to the shaft 4 and use simply the secondary generators activated by the APU (at least temporarily) . Obviously this solution is recommended particularly in flight conditions where are not requested elevated power and absorption by the engine and, alternatively, in some flight phases.

A second preferred configuration of the invention (look at figure 3) comprises, on the other hand, the use of more electric engines 205 connected to a sole central rotating shaft 204 and still fed by power supply means 7. The number of engine can thus change according to the needs. A particularly advatageous solution can comprise a number of engines variable from two to a maximum of six, eventhough a number of engine greater than six can be easily used. In this case, the positioning configuration of the same is concentrical respect to the shaft, or rather placed on a star type structure to the shaft 204. In detail, a common main AC/DC (208) and ACW (209) power generator is keyed on the central shaft 204 while the engines are placed around the shaft in their supporting sites and connected to it throu gearboxes 206. The functioning remains totally equivalent to what has been described for the single engine. Figure 4 describes, accordino to a simple block diagram, the logical functioning of the present invention in its essential aspects (the arrows indicate the connection) . In particular it is highlighted the electric engine doubly connected (or rather releasable mechanical and electrical connection ) to main AC/DC/ACW generators. The direction of the arrow from the engine to the generator indicates the mechanic connection that activates the same generators for the power production, while the connection of the arrow from the generator to the engine indicates the power supply (look Inverter interplaced to correct the voltage input entering the engine) . The block diagram shows also the electric connection of the main and secondary batteries packs to the engine to feed it, beyond to the electric connection of the main generators to the main and secondary batteries pack to feed them. The solar collectors and/or the aeolic devices feed the ulteriorly the batteries in combination to the main generators and eventually secondary utilities of the aircraft. The upper part of the flowchart highlights also the APU connected to the secondary generators to feed the batteries or directly the engine (as said in such case it is possible to release mechanically from the engine the main generators) .

In figure 5 it is also highlited, in order to clarify, a complex schematic view of the aircraft composed by the electric engine and the power supply means according to the invention. It is particularly visible the electric connection (connection arrows) that supplies power from the main battery pack to the engine (look the supply direction of the arrow) . Are also visible the electric panels 10 and the aeolic devices 10' that, in this case, feed in combination the batteries along to the main generators 8. It is also highlighted the predisposition of the APU at the tail of the aircraft.

It is at this point clear how the aims of the present inventing have been reached. In particular it is clear how the combination of at least an electric engine to come power supply means of the engine allows to eliminate entirely the fuel costs. The pollution problem is almost totally resolved, not producing any discharges harmful for the environment (except for little fuel auxiliary devices as APU and limilar) . Moreover the noise is highly pulled down. The above description of a specific shape is able to show the invention from the conceptive point of view, in a way that others, by using the art, can modify and/or adapt in different applications this specific shape without any further research and without going apart from the inventive concept, and, therefore, it is intended that these adaptations and transformations will be considered as equivalent to this specific realization. The means and materials to make the many described functions can be of various nature without exiting the area of the invention. it is intended that the expressions or the terminology used have a simple descriptive aim and therefore not limiting.

Claims

1. Device to generate the thrust of an aircraft in general and comprising means (1) operatively connected to at least a propeller (2) , said means determining the rotation of the propeller to generate the thrust of the aircraft and characterized by the fact that the mentioned means comprise in combination at least an electric engine (5; 205) connected to means of power supply (7), said power supply means supplying power to the engine to allow its functioning.

2. Device to generate the thrust of an aircraft in general, according to claim 1, where said meand of power supply (7) comprise one of the following choices :

- At least a main battery (11);

- At least an electric current generator (8; 208) AC/DC and/or DCW (9; 209); - At least a main battery (11) in combination to at least an electric current generator (8; 208) AC/DC and/or ACW (9; 209) ;

- At least a solar collector (10) and/or aeolic devices (10' ) .

3. Device to generate the thrust of an aircraft in general, according to claim 1 and 2, where it is comprised a secondary spare battery (12) electrically connected to said electric engine (5; 20-5) .

4. Device to generate the thrust of an aircraft in general, according to claim 2 and 3, where it is comprised a main battery pack (11) and a secondary spare battery pack (12) .

5. Device to generate the thrust of an aircraft in general, according to one or more of the previous claims, where are comprised recharging means (8, 10, 10', 17; 208) connected at least to the main battery (11) and/or to said secondary battery (12), said means allowing to recharge said batteries at least during the flight phase.

6. Device to generate the propulsion of an aircraft in general, according to one or more of the previous claims, where said recharging means comprise at least one of ^'the following choices:

- the main current generator (8; 208) AC/DC, said generator being activated by the electric engine to produce current .

- at least a solar collector (10) and/or aeolic devices (10' ) electronically connected to said batteries . - the main current generator (8; 208) in combination with said solar collector (10) and/or with siad aeolic devices (10' ) .

7. Device to generate the thrust of an aircraft in general, according to one or more of the previous claims, where said main AC/DC generator (8; 208) and said secondary ACW generator (9; 209) are keyed on a shaft (4; 204), said main generator (8;208) being mechanically connected in a releasable manner to the electric engine through mechanical unhooking means, said mechanical unhooking means can be activated into a working position where they bind the generator to the shaft (4; 204) to make it rotate producing electric current that can be sent to said batteries and/or to said engine and a neutral position where said generator does not result integral to the shaft (4; 204) .

8. Device to generate the thrust of an aircraft in general, according to one or more of the previous claims, where said electric engine (5; 205) is connected to said shaft (4; 204) through a gearbox (6; 206) , said gearbox changing the number of revolutions in input to said shaft (4) .

9. Device to generate the thrust of an aircraft in general, according to one or more of the previous claims, where the engine is connected in a releasable mannet to the main ACW current generator (9; 209), said ACW feeding the remaining utiliies of the aircraft .

10. Device to generate the thrust of an aircraft in general, according to one or more of the previous claims, where at least an Inverter is interplaced in the points of inputs of current to the engine.

11. Device to generate the thrust of an aircraft in general, according to one or more of the previous claims, where the global number of electric engine connected to the single propeller is variable according to one of the following choices: - A single electric engine (5); - A number of electric engine (205) greater than one, in function to the required power.

12. Propulsion device for aircraft in general, according to claim 11, where the number of engines (205) is greater than one, these result placed concentrally respect to the rotating shaft (204) of the propeller on a star type structure, said gearbox (206) connecting said engine to said rotating shaft of the propeller.

^•13. Propulsion device for aircraft in general, according to one or more of the previous claims, where it is comprised a secondary AC/DC current generator (17) mechanically connected to an APU, said APU activating said secondary generator to feed said batteries and/or said engine (5; 205) .

14. Propulsion device for aircraft in general, according to one or more of the previous claims, where said electric engine/s (5; 205) can be connected mechanically and electrically to said primary and secondary generators according to one of the following choices : - Primary generator mechanically disconnected from the engine (5; 205) and secondary generator in function by means of the APU, said secondary generator being electrically connected to said batteries and/or said engine; - the main generator mechanically and/or electrically connected to the engine (5; 205) and said second generator disconnected from the APU;

- Primary generator electrically and/or mechanically connected to the engine and said secondary generator in function by means of the APU, said secondary generator feeding the engine and/or said batteries ;

15. An aircraft in general, as helicopters, airplanes and amphibian, comprising means (1) able to activate at least one propeller (2) to generate the thrust and characterized by the fact that said means comprise:

- At least an electric engine (5; 205) connected mechanically and/or electrically to at least a main

5 generator AC/DC (8; 208) and/or ACW (9; 209), said electric engine driving into rotation the propeller and activating said generator to produce current;

- At least a main battery (11) electrically connected to the engine (5; 205) and to said generator (8; 208),

10 said battery feeding the engine during its functioning and said generator recharging said battery.

16. Aircraft in general, as helicopters, airplanes and amphibian, characterized by the fact that it comprises 15 a device as in the previous claims from 1 to 14.

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