Electric power generation system for an aircraft with a hybrid energy source

Abstract

An electrical power generation system for an aircraft with a hybrid energy source comprises a combustion engine (23) arranged to provide mechanical power. The system further comprises power electronics (21) arranged to convert the mechanical power provided by the engine (23) into electrical power for propelling the aircraft. The system further comprises a heat exchanger (33) connected to the power electronics (21). The system further comprises a gas inlet (11) and a gas outlet (13). The system further comprises a gas circuit fluidly connecting the gas inlet (11) to the gas outlet (13). The gas circuit opens onto the gas outlet (13) at least via an evacuation pipe (41). This evacuation pipe (41) has an end portion (42), opposite the gas outlet (13).The gas circuit comprises a first circuit, arranged to supply the engine (23) with air from the gas inlet (11) and to discharge exhaust gases from the engine (23) to the end portion (42) of the discharge pipe (41). The gas circuit further comprises a second circuit, fluidically connecting the gas inlet (11) to the end portion (42) of the discharge pipe (41). The second circuit is arranged to receive a flow of air from the gas inlet (11) and suitable for cooling the heat exchanger (33). This flow of air is generated by jet pump effect when the exhaust gases pass through the end portion (42) of the discharge pipe (41). Abstract figure: [Fig.1].

Description

Title of the invention: Electrical power generation system for an aircraft with a hybrid energy source

[0001] The invention relates to the field of aircraft with a hybrid energy source. More particularly, the invention relates to electrical power generation systems for such aircraft.

[0002] An aircraft generally comprises a main power unit, which provides the power necessary for its propulsion and lift. This main power unit is, typically, integrated into the fuselage of the aircraft.

[0003] Nowadays, for most aircraft, the main power unit is of the thermal type, that is to say that this unit generates mechanical power from a thermal energy source. Typically, this unit can include a combustion engine connected to a propeller, or even a turbojet.

[0004] Furthermore, an aircraft often includes one or more auxiliary power units, also called APUs in the art (from the English equivalent “Auxiliary Power Units”). An APU is generally formed of a turbogenerator, arranged to generate electrical power from a thermal energy source. Typically, this electrical power is of the order of a few tens of kilowatts. The turbogenerator includes an electronic part, which generally operates at voltages of the order of a hundred volts.

[0005] An APU is designed to provide electrical power to the aircraft transiently. For example, this power is intended to power on-board systems of the aircraft, when the aircraft is on the ground and its main power unit is stopped. This power may, in addition, be intended to assist the (re)starting of the main power unit of the aircraft, when the aircraft is on the ground or in flight.

[0006] An aircraft is said to have a “hybrid energy source” when its main power unit is of the hybrid type, that is to say that this unit comprises an electrical power generation system, capable of generating electrical power from a thermal energy source. Typically, such an electrical power generation system comprises a fuel cell or a combustion engine, arranged to produce mechanical power from the combustion of a fuel, and an electrical generation part, arranged to convert the mechanical power supplied by the combustion engine into electrical power. This electrical power is then, generally, stored in one or more batteries, for later use for the propulsion or lift of the aircraft.

[0007] The electrical power generation system of a hybrid main power unit must generate much higher electrical power than that generated by the turbogenerator of an APU. Furthermore, unlike an APU, the electrical power generation system of a hybrid main power unit is designed to operate continuously while the aircraft is in flight.

[0008] Thus, unlike an APU, an electrical power generation system of a hybrid main power unit generally comprises a power electronics portion. This power electronics is capable of generating, from the mechanical power supplied by the combustion engine, sufficient electrical power to ensure the propulsion and lift of the aircraft. Typically, the power electronics handles powers between 100 kW and 1 MW. The power electronics may comprise several types of devices, such as electrical generators and inverters. Typically, these devices operate at voltages between 500 V and 800 V.

[0009] The operation of the power electronics of the electrical power generation system results in a release of heat, much greater than that caused during the operation of the electrical generation part of an APU. In order to avoid the formation of hot spots within the system, it is necessary to provide a cooling circuit to evacuate this heat. Typically, the operation of the power electronics results in a release of heat, the thermal power of which can reach several tens of kilowatts.

[0010] Preferably, the cooling circuit involves the circulation of a heat transfer liquid or coolant. This coolant heats up in the vicinity of the power electronics and cools down in the vicinity of an air circulation. In this way, the heat released by the power electronics dissipates quickly, without creating hot spots. The cooling circuit comprises a heat exchanger, arranged to ensure the transfer of heat between the coolant and the air circulation. The coolant is, for example, a mixture of water and glycol.

[0011] In a known manner, a gas circuit is provided to receive this air circulation, fluidly connecting a gas inlet and a gas outlet to each other. This gas inlet and this gas outlet are, for example, produced in the form of openings provided on a portion of the fuselage fairing. The gas circuit takes in fresh air from the external environment via the gas inlet. The gas circuit then circulates this air close to the heat exchanger, so as to ensure the dissipation of the heat carried by the coolant. The gas circuit finally evacuates this air via the gas outlet.

[0012] The air circulation in the gas circuit must have a minimum flow rate so that The heat exchanger effectively dissipates the heat generated by the power electronics. In particular, this minimum flow rate must be achievable even when the aircraft is stationary.

[0013] In order to guarantee this flow rate, a solution of the state of the art consists of providing for the installation of an electric fan near the heat exchanger. This fan ensures, by its rotation, air circulation at the necessary flow rate, even when the aircraft is stationary. This solution is not, however, satisfactory, because the presence of the fan induces additional mass and bulk for the system. In addition, the operation of the fan consumes electricity.

[0014] The invention improves the situation.

[0015] To this end, the Applicant proposes a system for generating electrical power for an aircraft with a hybrid energy source. The system comprises a combustion engine arranged to provide mechanical power. The system further comprises power electronics arranged to convert the mechanical power provided by the engine into electrical power for the propulsion of the aircraft. The system further comprises a heat exchanger connected to the power electronics. The system further comprises a gas inlet and a gas outlet. The system further comprises a gas circuit fluidly connecting the gas inlet to the gas outlet. The gas circuit opens onto the gas outlet at least via an evacuation pipe. This evacuation pipe has an end portion, opposite the gas outlet.The gas circuit comprises a first circuit, arranged to supply the engine with air from the gas inlet and to discharge exhaust gases from the engine to the end portion of the discharge pipe. The gas circuit further comprises a second circuit, fluidly connecting the gas inlet to the end portion of the discharge pipe. The second circuit is arranged to receive a flow of air from the gas inlet and suitable for cooling the heat exchanger. This flow of air is generated by jet pump effect when the exhaust gases pass through the end portion of the discharge pipe.

[0016] This system allows the power electronics to be cooled efficiently, even when the aircraft is stationary. The jet pump effect makes it possible to take advantage of the exhaust gases from the combustion engine to create an air circulation whose flow rate is sufficient to dissipate the heat released by the power electronics. It is therefore possible to do without an electric fan, or at least reduce its size and power. The result is an electric power generation system that is lighter, less bulky and less energy-intensive.

[0017] Optional features of the invention, complementary or substitutable, are set out below:

[0018]

[0019]

[0020]

[0021]

[0022] - the power electronics are capable of providing electrical power between 100 kW and 1 MW; - the power electronics are suitable for operating at voltages between 500 V and 800 V; - the engine and power electronics are designed to operate continuously when the aircraft is in flight; - the system further comprises an engine block, housing the engine, the power electronics and the heat exchanger, the engine block delimiting, at least in part, a conduit for the second circuit, and the circulation of air suitable for cooling the heat exchanger being further suitable for ensuring renewal of the air inside the engine block; - the first circuit comprises an exhaust pipe, arranged to discharge exhaust gases from the engine towards the end portion of the exhaust pipe; - a ratio between a section at the outlet of the exhaust pipe and a section at the inlet of the end portion is of the order of 1:2; - the distance between an outlet of the exhaust pipe and an inlet of the end portion is substantially zero; - the heat exchanger is arranged near the gas inlet, at a distance from the end portion of the discharge pipe; - the end portion of the discharge pipe has a clearance, the heat exchanger being arranged close to this clearance. The invention also relates to a hybrid energy source aircraft comprising this system. Other characteristics and advantages of the invention are set out in detail in the following description, given with reference to the appended drawings, in which: - [Fig.l] is a schematic representation of an electrical power generation system, according to a first embodiment of the invention; - [Fig.2] is a schematic representation of an electrical power generation system, according to a second embodiment of the invention; - [Fig.3] is a schematic representation of another electrical power generation system. The drawings and the description below contain, for the most part, elements of a certain character. They may therefore not only serve to better understand the present invention, but also contribute to its definition, if necessary. Reference is made to [Fig.l]. This figure represents an electrical power generation system, according to a first embodiment of the invention. This system is designated by the reference digital 10 in the drawings and in the rest of the description.

[0023] The system 10 is intended to generate electrical power for an aircraft with a hybrid energy source. In particular, the system 10 is arranged to generate electrical power for the propulsion and lift of the aircraft. Typically, the system 10 is integrated inside the fuselage of the aircraft. The system 10 may, as here, be integrated near a fairing portion 15 belonging to the fuselage.

[0024] The system 10 comprises a hybrid power unit, capable of generating electrical power from a thermal energy source. The system 10 is designed to operate continuously, when the aircraft is in flight.

[0025] The hybrid power unit comprises a thermal power unit, arranged to provide mechanical power from the thermal energy source. Here, the thermal energy source is a fuel, in particular a fuel. This fuel is, for example, stored in a tank of the aircraft (not shown in the figures). The thermal power unit is arranged to provide mechanical power from the combustion of the fuel. The thermal power unit is supplied with air, in a manner which is detailed later. The operation of the thermal power unit results in exhaust gas emissions, which are discharged in a manner which is detailed later.

[0026] The thermal power unit may comprise one or more examples of combustion engines. Here, the thermal power unit comprises one example of combustion engine, or engine 23. The engine 23 may, for example, be a piston engine or a turboshaft engine.

[0027] The hybrid power unit further comprises a power electronics part 21, arranged to generate, from the mechanical power supplied by the thermal engine unit, an electrical power intended to ensure the propulsion and lift of the aircraft. Typically, the power electronics 21 processes powers between 100 kW and 1 MW.

[0028] The power electronics 21 comprises an electricity generation part, mechanically connected to the thermal motor unit. The electricity generation part is arranged to generate the electrical power from the mechanical power supplied by the thermal motor unit.

[0029] The electricity generation part may comprise one or more examples of electric generators. Here, the power electronics 21 comprises an example of electric generator, or generator 25, mechanically connected to the motor 23.

[0030] The power electronics 21 may further comprise, as here, other power electronic devices. These devices are electrically connected to the electricity generation part. These devices are arranged to use or transform the electrical power generated by the electricity generation part, in particular for storage in a battery (not shown in the figures). This electrical power is subsequently used for the propulsion and lift of the aircraft.

[0031] Here, the power electronics 21 comprises an inverter 27, electrically connected to the generator 25.

[0032] Typically, electrical generators and other power electronic devices 21 operate at voltages between 500 V and 800 V.

[0033] The system 10 further comprises a cooling circuit 31, arranged to evacuate at least part of the heat released by the operation of the power electronics 21. Here, the cooling circuit 31 is arranged to cool the generator 25 and the inverter 27.

[0034] The cooling circuit 31 comprises a heat exchanger 33. This heat exchanger 33 is arranged to dissipate the heat released by the operation of the power electronics 21, as detailed later.

[0035] Here, the cooling circuit 31 further comprises a pipe shaped as a cooling loop 35. This cooling loop is arranged to receive the circulation of a heat transfer liquid or coolant. The cooling loop 35 is connected, on the one hand, to the power electronics 21, and, on the other hand, to the heat exchanger 33. The cooling loop 35 is arranged to capture the heat released by the operation of the power electronics 21 and convey this heat to the heat exchanger 33. Here, the coolant is a mixture of water and glycol.

[0036] Here, the system 10 further comprises an engine block 17, housing the hybrid power unit. The engine block 17 is arranged to provide protection for the hybrid power unit in the event of a fire. Here, the engine block 17 houses the engine 23, the generator 25 and the inverter 27. Here, the engine block 17 also houses the cooling circuit 31. In particular, the engine block 17 houses the heat exchanger 33 and the cooling loop 35.

[0037] The system 10 further comprises a gas inlet 11 and a gas outlet 13. Here, the gas inlet 11 is shaped as a first opening, arranged on the fairing portion 15. Here, the gas outlet 13 is shaped as a second opening, arranged on the fairing portion 15.

[0038] The system 10 further comprises a gas circuit, which fluidly connects the gas inlet 11 to the gas outlet 13. The circulation of gases from the gas inlet 11 to the gas outlet 13 is represented by the arrows 81, 83, 85, 87 and 89. These arrows illustrate a direction for the circulation of gases in the gas circuit.

[0039] The gas circuit is arranged to supply the engine 23 with air coming from the inlet of gas 11. The air flow coming from the gas inlet 11 and supplying the engine 23 is represented by the arrow 81. The gas circuit is further arranged to discharge exhaust gases from the engine 23 through the gas outlet 13. The flow of exhaust gas coming from the engine 23 and discharged by the gas circuit towards the gas outlet 13 is represented by the arrows 83 and 85.

[0040] The gas circuit is further arranged to receive an air circulation, suitable for cooling the cooling circuit 31. In particular, the gas circuit is arranged so that the heat exchanger 33 ensures a heat transfer between the cooling liquid and this air circulation. The air circulation dissipates the heat released by the operation of the power electronics 21 and transported to the heat exchanger 33 by the cooling liquid circulating in the cooling loop 35.

[0041] The circulation of air cooling the cooling circuit 31 comprises an air flow represented by the arrows 89, 87 and 85. This air flow is evacuated through the gas outlet 13. Here, this air flow comes from the gas inlet 11.

[0042] The gas circuit comprises an evacuation pipe 41, opening onto the gas outlet 13. The gas circuit is arranged to evacuate exhaust gases from the engine 23 via the evacuation pipe 4L. The gas circuit is further arranged to evacuate the air flow cooling the cooling circuit 31 via the evacuation pipe 4L.

[0043] The discharge pipe 41 has an end portion 42, arranged on one end of the discharge pipe 41 opposite the gas outlet 13. Here, the discharge pipe 41 is fluidically connected to the engine block 17 via this end portion 42.

[0044] The gas circuit has a first circuit, or motor circuit 46, arranged to serve the motor 23. The motor circuit 46 forms a first path for the passage of gas flows between the gas inlet 11 and the end portion 42. The motor circuit 46 is arranged to supply the motor 23 with air and to evacuate the exhaust gases emitted by the motor 23. The motor circuit 46 is connected to the end portion 42 of the evacuation pipe 4L

[0045] Here, the engine circuit 46 comprises a supply line 45, which fluidly connects the gas inlet 11 to the engine 23, and an exhaust line 47, which fluidly connects the engine 23 to the end portion 42. The supply line 45 is arranged to supply the engine 23 with air. The exhaust line 47 is arranged to discharge the exhaust gases emitted by the engine 23 to the end portion 42. Here, the exhaust line 47 opens into the end portion 42. The supply line 45 receives the air flow represented by the arrow 81. The exhaust line 47 receives the flow of exhaust gases re- presented by arrow 83.

[0046] The gas circuit further has a second circuit, or air circuit, arranged to cool the cooling circuit 31. The air circuit forms a second path for the passage of gas flows between the gas inlet 11 and the end portion 42. In particular, the air circuit is arranged to receive the circulation of air cooling the heat exchanger 33. The air circuit fluidically connects the gas inlet 11 to the end portion 42 of the discharge pipe 4L.

[0047] The air circuit comprises a first duct, arranged to conduct the air cooling the cooling circuit 31 to the end portion 42. Here, this first duct is formed by an enclosure 49, delimited in part by the engine block 17. The enclosure 49 receives the air flow represented by the arrows 87.

[0048] The air circuit further comprises a second conduit or inlet conduit 51, which fluidically connects the gas inlet 11 to its first conduit, here the enclosure 49. The inlet conduit 51 receives the air flow represented by the arrow 89.

[0049] The first pipe of the air circuit fluidly connects the inlet pipe 51 and the end portion 42. The first pipe of the air circuit is arranged to conduct the air cooling the cooling circuit 31, from one end of the inlet pipe 51 to the end portion 42 of the discharge pipe 4L.

[0050] Here, the engine circuit 46 and the air circuit are distinct from each other, over their entire length. The engine circuit 46 and the air circuit join at the end portion 42 of the exhaust duct 4L. The supply duct 45 of the engine circuit 46 is distinct from the inlet duct 51 of the air circuit. In addition, the supply duct 45 and the exhaust duct 47 of the engine circuit 46 participate in delimiting, with the engine block 17, one of the ducts of the air circuit, namely the enclosure 49.

[0051] Here, the heat exchanger 33 is arranged near the gas inlet 11. In particular, the heat exchanger 33 is arranged in the enclosure 49, near the end of the inlet pipe 51.

[0052] The fairing portion 15 may, as here, have, on the gas inlet 11, a projecting part forming a first deflector 16. This first deflector 16 is arranged to guide air flows towards the gas inlet 11, in particular towards the supply pipe 45 and towards the inlet pipe 51.

[0053] The gas circuit is arranged to generate, by jet pump effect, the circulation of air cooling the cooling circuit 31, when the exhaust gases of the engine 23 pass through the end portion 42. In particular, the gas circuit is arranged to cause, by jet pump effect, a suction of the flow of air cooling the heat exchanger 33, when the exhaust gases of the engine 23 pass through the end portion 42.

[0054] The jet pump effect is also known in the art by its English equivalent "jet pump effect". This effect refers to the fact that a fluid flow creates a low pressure zone, which tends to draw other fluids into this flow.

[0055] When the engine 23 is operating, it releases exhaust gases. These exhaust gases are received in the exhaust pipe 47 of the engine circuit 46. This exhaust pipe 47 guides the exhaust gases towards the end portion 42 of the discharge pipe 41, as represented by the arrow 83. When the exhaust gases pass through the end portion 42, this creates a jet pump effect, capable of generating an air intake at the gas inlet 11. This effect causes both an air suction in the supply pipe 45 of the engine circuit 46, as represented by the arrow 81, and an air suction in the inlet pipe 51 of the air circuit, as represented by the arrow 89. The air sucked into the inlet pipe 51 then enters the enclosure 49, where this air cools the cooling circuit 31, during a heat transfer carried out by the heat exchanger 33.This air then circulates in the enclosure 49, as represented by the arrows 87, until it reaches the end portion 42. This air is then evacuated via the evacuation pipe 41, as are the exhaust gases coming from the engine 23.

[0056] Here, the discharge pipe 41 has a variable section. In particular, the end portion 42 has a section which decreases progressively in the direction of circulation of the gases in the gas circuit. This configuration of the end portion 42 makes it possible to limit the pressure losses in the flow at the inlet of the discharge pipe 4L. Here, the discharge pipe 41 also has a portion of constant section 43, which fluidically connects the end portion 42 to the gas outlet 13.

[0057] Thanks to the invention, efficient dissipation of the heat released by the power electronics 21 is ensured, even when the aircraft is stationary. The air intake generated by the jet pump effect makes it possible to drive an air circulation of a flow rate sufficient to cool the cooling circuit 31. In particular, this air flow rate is sufficient to dissipate a heat release whose thermal power is of the order of several tens of kilowatts.

[0058] The flow rate of the air circulation depends on structural arrangements of the system 10.

[0059] This flow rate depends on the arrangement of the exhaust pipe 47 and the portion end portion 42 of the exhaust pipe 4L For example, the flow rate depends on the ratio between the outlet section of the exhaust pipe 47 and the section at the inlet of the end portion 42. Preferably, as here, this ratio is of the order of 1:2.

[0060] Furthermore, the flow rate depends on the relative position of the exhaust pipe 47 and the end portion 42. Here, the distance between the outlet of the pipe exhaust pipe 47 and the inlet of the end portion 42 is zero. Alternatively, the exhaust pipe 47 may be arranged, at least in part, through the end portion 42, over a length substantially equal to the diameter of the section at the inlet of the end portion 42. Alternatively, the outlet of the exhaust pipe 47 may be arranged at a distance from the inlet of the end portion 42 substantially equal to the diameter of the section at the inlet of the end portion 42. Alternatively, the exhaust pipe 47 and the end portion 42 may be in a relative position intermediate between those described above.

[0061] The flow rate of the air circulation further depends on the sizing of the pipes at the gas inlet 11. For example, the flow rate depends on the ratio between the cross-section of the supply pipe 45 of the motor circuit 46 and the cross-section of the inlet pipe 51 of the air circuit. Preferably, as here, the supply pipe 45 of the motor circuit 46 has a cross-section smaller than that of the inlet pipe 51 of the air circuit.

[0062] These structural arrangements participate in generating, by jet pump effect, an air circulation of a flow rate sufficient to cool the cooling circuit 31.

[0063] The flow rate of the air circulation also depends on the speed of the engine 23. In particular, when the engine 23 operates at a high speed, a concomitant increase in the heat released by the power electronics 21 and the flow rate of the air circulation in the gas circuit is observed.

[0064] The operation of the hybrid power unit in the engine block 17 causes the air present in this engine block 17 to heat up.

[0065] In this embodiment, the heat exchanger 33 is arranged close to the gas inlet 11. This arrangement makes it possible to expose the heat exchanger 33 to a flow of air at outside temperature, in particular before this air is heated by its passage through the engine block 17.

[0066] Furthermore, the use of the engine block 17 to delimit one of the ducts of the air circuit allows the circulation of air cooling the cooling circuit 31 to also ensure renewal of the air inside the engine block 17. This provides ventilation of the enclosure 49.

[0067] Reference is made to [Fig.2].

[0068] This figure represents a second embodiment of the electrical power generation system according to the invention. This second embodiment differs from the first embodiment essentially by the arrangement of its cooling circuit, in particular the arrangement of its heat exchanger. Elements similar to those described in relation to [Fig.l] bear the same numerical references.

[0069] In this second embodiment, the heat exchanger 33 is arranged close to the end portion 42 of the discharge pipe 41. The cooling loop 35 is elongated compared to that of the first embodiment.

[0070] The arrangement of the end portion 42 is further modified so as to form a clearance 44 near the heat exchanger 33. This clearance 44 makes it easier to integrate the heat exchanger 33. This clearance 44 also makes it possible to increase the circulation of air around the heat exchanger 33, and therefore to cool it more efficiently.

[0071] Reference is made to [Fig.3].

[0072] This figure represents a third embodiment of a jet pump effect electric power generation system. Elements similar to those described in relation to [Fig.l] bear the same numerical references.

[0073] This third embodiment is distinguished from the first embodiment by the arrangement of its cooling circuit 31, in particular the arrangement of its heat exchanger 33, and by the arrangement of its gas circuit.

[0074] In this third embodiment, the heat exchanger 33 and a portion of the cooling loop 35 are arranged outside the engine block 17. The heat exchanger 33 and this portion of the cooling loop 35 are arranged between the engine block 17 and the fairing portion 15. The heat exchanger 33 is arranged near the gas inlet 11. The engine block 17 has, for example, bores, arranged to allow the passage of the cooling loop 35. The cooling loop 35 connects the power electronics 21, housed inside the engine block 17, and the heat exchanger 33, arranged outside thereof.

[0075] In this third embodiment, the gas circuit comprises a main circuit and a secondary circuit, distinct from each other.

[0076] The main circuit is arranged to serve the engine 23 and provide ventilation for the engine block 17. The main circuit fluidly connects the gas inlet 11 to the gas outlet 13. The main circuit comprises the discharge pipe 41, in particular the end portion 42 thereof. The main circuit further comprises the engine circuit 46 as described in relation to [Fig.l].

[0077] The main circuit further comprises an inlet duct 151, structurally analogous to the inlet duct described in relation to [Fig.l]. The main circuit further comprises an enclosure 149, structurally analogous to the enclosure described in relation to [Fig.l]. The inlet duct 151 and the enclosure 149 of the third embodiment have different functions from those described for the inlet duct and the enclosure of the first embodiment. Unlike what has been described in relation to [Fig.l], the air flow which enters through the inlet duct 151, as represented by arrow 99, then which circulates in the enclosure 149, as represented by the arrows 97, is only intended for the ventilation of the engine block 17. This air flow does not ensure the cooling of the cooling circuit 31. In particular, this air flow does not ensure the cooling of the heat exchanger 33, which is located outside the enclosure 149.

[0078] The secondary circuit is arranged to ensure the cooling of the cooling circuit 31. In particular, the secondary circuit is arranged to receive the circulation of air cooling the heat exchanger 33. The secondary circuit fluidly connects the gas inlet 11 to the gas outlet 13. The secondary circuit comprises an air duct 53, which fluidly connects the gas inlet 11 to the gas outlet 13. Here, the air duct 53 is delimited, in part, by the fairing portion 15, the engine block 17, the exhaust duct 41, the inlet duct 151 and the supply duct 45.

[0079] The fairing portion 15 may, as here, have, on the gas inlet 11, another projecting part forming a second deflector 20. The fairing portion 15 may, as here, have, on the gas outlet 13, a projecting part forming a third deflector 18. The second deflector 20 and the third deflector 18 are arranged to partially delimit the air duct 53.

[0080] When the exhaust gases from the engine 23 pass through the end portion 42 of the exhaust duct 41, a first jet pump effect, similar to that described in relation to [Fig.l], causes both an air suction into the supply duct 45, as shown by the arrow 81 and an air suction into the inlet duct 151, as shown by the arrow 99. To a lesser extent, this first jet pump effect also causes an air suction into the air duct 53, as shown by the arrow 189.

[0081] Furthermore, when the exhaust gases exit the discharge pipe 41, this causes, at the gas outlet 13, a second jet pump effect. This second jet pump effect contributes to causing the suction of air into the air pipe 53, at the gas inlet 11.

[0082] The air sucked into the air duct 53, represented by the arrow 189, cools the heat exchanger 33, then circulates along the air duct 53, as represented by the arrows 187. This air is then evacuated through the gas outlet 13.

[0083] The arrangement of the heat exchanger 33 between the engine block 17 and the fairing portion 15 makes it possible to reduce the size of the system 10.

[0084] The invention is not limited to the embodiments described above, but encompasses all variants conceivable by those skilled in the art.

Claims

Claims

1. Electrical power generation system for an aircraft with a hybrid energy source, the system comprising: - a combustion engine (23) arranged to provide mechanical power, - power electronics (21) arranged to convert the mechanical power provided by the engine (23) into electrical power for the propulsion of the aircraft, - a heat exchanger (33) connected to the power electronics (21), - a gas inlet (11) and a gas outlet (13), - a gas circuit fluidly connecting the gas inlet (11) to the gas outlet (13), the gas circuit opening onto the gas outlet (13) at least via an evacuation pipe (41), this evacuation pipe (41) having an end portion (42), opposite the gas outlet (13), the gas circuit comprising a first circuit,arranged to supply the engine (23) with air from the gas inlet (11) and to discharge exhaust gases from the engine (23) to the end portion (42) of the discharge pipe (41), the gas circuit further comprising a second circuit, fluidly connecting the gas inlet (11) to the end portion (42) of the discharge pipe (41), the second circuit being arranged to receive a circulation of air from the gas inlet (11) and suitable for cooling the heat exchanger (33), this circulation of air being generated by jet pump effect when the exhaust gases pass through the end portion (42) of the discharge pipe (41).,

2. System according to claim 1, in which the power electronics (21) is capable of providing electrical power of between 100 kW and 1 MW.

3. System according to one of claims 1 and 2, in which the power electronics (21) is capable of operating at voltages between 500 V and 800 V.

4. System according to one of claims 1 to 3, in which the motor (23) and the power electronics (21) are designed to operate continuously when the aircraft is in flight.

5. System according to one of claims 1 to 4, further comprising an engine block (17), housing the engine (23), the power electronics (21) and the heat exchanger (33), the engine block (17) delimiting, at least in part, a conduit for the second circuit, and the circulation of air suitable for cooling the heat exchanger (33) being further suitable for ensuring renewal of the air inside the engine block (17).

6. System according to one of claims 1 to 5, in which the first circuit comprises an exhaust pipe (47), arranged to discharge exhaust gases from the engine (23) towards the end portion (42) of the exhaust pipe (41).

7. System according to claim 6, in which a ratio between an outlet section of the exhaust pipe (47) and an inlet section of the end portion (42) is of the order of 1:

2.

8. System according to one of claims 6 and 7, in which the distance between an outlet of the exhaust pipe (47) and an inlet of the end portion (42) is substantially zero.

9. System according to one of claims 1 to 8, in which the heat exchanger (33) is arranged close to the gas inlet (11), at a distance from the end portion (42) of the discharge pipe (41).

10. System according to one of claims 1 to 8, in which the end portion (42) of the discharge pipe (41) has a clearance (44), the heat exchanger (33) being arranged close to this clearance (44).

11. A hybrid power source aircraft, comprising the system of one of claims 1 to 10.

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