HYBRID PROPULSION SYSTEM FOR A MULTI-ENGINE AIRCRAFT

Abstract

The hybrid propulsion system for a multi-engine aircraft includes a plurality of free-turbine engines, each having a gas generator, among which at least a first engine, or hybrid engine, is suitable for operating in at least one standby mode during stabilized flight of the aircraft, while other engines of the plurality of engines operate alone during such stabilized flight. The hybrid engine is associated with first and second identical electric powertrains, each including a respective electrical machine capable of operating as a starter and as a generator, itself connected to a respective electronic power module, itself selectively connected to a specific electrical power supply network, such as an onboard network, and to a respective at least one electrical energy storage member. Each of the electric powertrains is adapted to deliver maximum power not less than half the total power needed for rapid reactivation of the hybrid engine.

Claims

1. A hybrid propulsion system for a multi-engine aircraft, the system comprising: a plurality of free-turbine engines each having a gas generator, and including at least one first engine, referred to as a “hybrid” engine, that is suitable for operating in at least one standby mode during stabilized flight of the aircraft, while other engines of said plurality of engines operate alone during such stabilized flight, the hybrid engine being associated with at least one first electric powertrain comprising a first electrical machine capable of operating as a starter and as a generator, itself connected to a first electronic power module, itself selectively connected to a specific electrical power supply network, such as an onboard network, and to at least one first electrical energy storage member, said hybrid engine also being associated with a second electric powertrain identical to said first electric powertrain and comprising a second electrical machine capable of operating as a starter and as a generator, itself connected to a second electronic power module, itself selectively connected to said specific electrical power supply network and to at least one second electrical energy storage member, wherein each of the first and second electric powertrains is adapted to deliver a maximum power not less than half the total power needed for rapid reactivation of said hybrid engine and in that each of the first and second electric powertrains is adapted to be capable of delivering to the hybrid engine in selective manner either normal reactivation power or starting power, or else standby power, or else half standby power, or else half rapid reactivation power.

2. The hybrid propulsion system according to claim 1, wherein said normal reactivation power or starting power is of the order of 20% of the total rapid reactivation power.

3. The hybrid propulsion system according to claim 1, characterized in that wherein said standby power is of the order of 3% to 5% of the total rapid reactivation power.

4. The hybrid propulsion system according to claim 1, wherein each of the first and second electronic power modules is adapted to be capable of receiving power respectively from the first or the second electrical energy storage member in order to power respectively in isolated manner and in alternation with the other of said first and second electronic power modules, each of the first and second electrical machines with normal reactivation power or starting power.

5. The hybrid propulsion system according to claim 1, wherein each of the first and second electronic power modules is adapted to be capable of receiving power respectively from the first or the second electrical energy storage member for powering respectively and simultaneously with the other of said first and second electronic power modules, each of the first and second electrical machines with half rapid reactivation power.

6. The hybrid propulsion system according to claim 1, wherein each of the first and second electronic power modules is adapted to be capable of receiving power from said specific electrical power supply network in order to power respectively and simultaneously with the other of said first and second electronic power modules the first and second electrical machines either with half starting power or with half normal reactivation power, or with half standby power.

7. The hybrid propulsion system according to claim 1, wherein each of the first and second electronic power modules is adapted to be capable of receiving power respectively from the first or the second electrical energy storage member in order to power respectively and simultaneously with the other of said first and second electronic power modules the first and second electrical machines, either with half normal reactivation power or half starting power, or else with half standby power.

8. The hybrid propulsion system according to claim 1, wherein each of the first and second electronic power modules is adapted to be capable of receiving power from said specific electrical power supply network in order to power respectively in isolated manner and in alternation with the other of said first and second electronic power modules, the first and the second electrical machines either with normal reactivation power or starting power, or else with standby power.

9. The hybrid propulsion system according to claim 4, wherein each of the first and second electronic power modules is adapted to be capable of receiving power from said specific electrical power supply network or respectively from the first or the second electrical energy storage member in order to power respectively in isolated manner and in alternation with the other of said first and second electronic power modules, or in simultaneous manner, the first and second electrical machines with variable power less than or equal to half the total power needed for rapid reactivation of said hybrid engine.

10. The hybrid propulsion system according to claim 1, characterized in that wherein the first and second electrical energy storage members comprise two storage members that are physically dissociated.

11. The hybrid propulsion system according to claim 1, wherein the first and second electrical energy storage members comprise two storage members that are distinct but physically grouped together.

12. A multi-engine aircraft: comprising the hybrid propulsion system according to claim 1.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0044] Other characteristics and advantages of the invention appear from the detailed description of particular embodiments of the invention given with reference to the accompanying drawings, in which:

[0045] FIG. 1 is a diagram of a hybrid architecture of a propulsion system for a turbine engine having two controlling electric powertrains in a first embodiment of the invention;

[0046] FIG. 2 is a diagram of a hybrid architecture of a propulsion system for a turbine engine having two controlling electric powertrains in a second embodiment of the invention;

[0047] FIG. 3 is a diagram showing the operation of the FIG. 1 hybrid architecture in standby mode with a single active controlling electric powertrain;

[0048] FIG. 4 is a diagram showing the operation of the FIG. 1 hybrid architecture in standby mode with two active controlling electric powertrain;

[0049] FIG. 5 is a diagram showing the operation of the FIG. 1 hybrid architecture in normal reactivation or starting mode with a single active controlling electric powertrain powered by an onboard network;

[0050] FIG. 6 is a diagram showing the operation of the FIG. 1 hybrid architecture in a normal reactivation or starting mode with a single active controlling electric powertrain powered by an electrical energy storage member;

[0051] FIG. 7 is a diagram showing the operation of the FIG. 1 hybrid architecture in normal reactivation or starting mode with two active controlling electric powertrains powered by the onboard network;

[0052] FIG. 8 is a diagram showing the operation of the FIG. 1 hybrid architecture in rapid reactivation mode with two active controlling electric powertrains powered by electrical energy storage members; and

[0053] FIG. 9 is a diagram showing the operation of the FIG. 1 hybrid architecture in a mode for carrying out variable power tests with two active controlling electric powertrains powered by the onboard network and by electrical energy storage members.

DETAILED DESCRIPTION

[0054] The hybrid propulsion system for a multi-engine aircraft of the invention comprises a plurality of free-turbine engines each equipped with a gas generator, among which engines at least a first engine, or hybrid engine, is suitable for operating in at least one standby mode during stabilized flight of the aircraft, while other engines of the plurality of engines are operating alone during the stabilized flight.

[0055] FIGS. 1 to 9 show the hybrid turbine engine 1 on its own together with the controlling electric powertrains of this hybrid engine, while the other engines in use may be conventional. Nevertheless, it is also possible on a single aircraft to make use of a plurality of hybrid engines analogous to the hybrid engine 1 described with reference to the accompanying drawings. The invention can thus apply to all of the engines of an aircraft of multi-engine architecture.

[0056] With reference to FIG. 1, it can be seen that the hybrid engine 1 is associated with first and second identical electric powertrains, each comprising a respective electrical machine 2, 3 capable of operating as a starter and as a generator, which machine is itself connected to a respective electronic power module 4, 5, itself selectively connected to a specific electrical power supply network 8, such as an onboard network, and to at least one electrical energy storage member, respectively 6, 7.

[0057] Each of the electric powertrains is adapted to deliver a maximum power that is not less than half the total power Prr needed for rapid reactivation of the hybrid engine 1.

[0058] FIG. 1 shows the first and second electrical energy storage members 6, 7, which comprise two storage members that are physically dissociated, each of which is capable of delivering at least half of the power and of the total energy needed for rapid reactivation of the engine 1, or each of which is capable of delivering the power necessary for normal reactivation of the engine 1.

[0059] Nevertheless, as shown in FIG. 2, the first and second electrical energy storage members may comprise two distinct storage members 66, 67 that are isolated from each other, but that are physically grouped together in a single physical entity 60, with each storage member constituting half of this entity.

[0060] The storage members 6, 7 or 66, 67, also referred to for short as “stores”, may be electrochemical or electrostatic in nature.

[0061] Each of the first and second electric powertrains is adapted to be capable of delivering selectively to the hybrid engine 1 either normal reactivation power or starting power Pdem, or else standby power Pv, or else half-standby power Pv/2, or else half-rapid reactivation power Prr/2.

[0062] Normal reactivation power or starting power is generally about 20% of the total rapid reactivation power Prr.

[0063] Standby power is generally about 3% to 5% of the total rapid reactivation power Prr.

[0064] Each dedicated electronic power module 4, 5 is capable of powering the corresponding electrical machine 2, 3 for a limited time with at least half of the power needed for rapid reactivation, i.e. Prr/2, or with the power needed for normal reactivation Pdem (which also corresponds to starting power).

[0065] Each dedicated electronic power module 4; 5 is itself supplied with energy either by the corresponding store 6, 66; 7, 67, or by the onboard network 8 of the aircraft, or by both together. It should be observed that the power available from the onboard network 8 is, a priori, limited since the onboard network 8 also needs to supply the electrical power needed for all of the onboard systems.

[0066] Each dedicated electronic power module 4, 5 is also capable of continuously powering the corresponding electrical machine 2, 3 for its use in the standby mode of the engine 1, and it is also adapted to control the corresponding electrical machine 2, 3 for the reliable starting procedure or for the normal reactivation procedure.

[0067] Each of the electrical machines 2, 3 is adapted to deliver at least half of the power needed for rapid reactivation, and the power needed for normal reactivation.

[0068] Furthermore, each electrical machine 2, 3 that drives the gas generator of a hybrid engine 1 is capable of maintaining that engine continuously in standby mode, of starting the engine 1, and of performing normal reactivation.

[0069] The engine 1 has an accessory gearbox suitable for receiving both electrical machines 2, 3, in addition to the standard equipment needed for proper operation of the engine 1.

[0070] With reference to FIGS. 3 to 9 there follows a description of the various modes of operation of the architecture of the invention. In these figures, elements of the architecture that are not active are drawn in dashed lines, while elements of the architecture that are active are drawn in normal manner with continuous lines.

[0071] FIGS. 3 and 4 show how the standby mode of the engine 1 can be implemented with the two electric powertrains in two different embodiments, in which energy is always taken from the onboard network 8.

[0072] As shown in FIG. 3, the power Pv needed for standby mode, which represents about 3% to 5% of the total available power Prr, can be delivered in alternation by the two electric powertrains on different missions.

[0073] FIG. 3 shows the electric powertrain including the first electrical machine 2 and the first electronic power module 4 powered by the onboard network 8 as being active while the second electrical machine 3, the second electronic power module 5, and the stores 6 and 7 are not involved. In a subsequent mission of the aircraft, the roles should be interchanged so that it is the second electrical machine 3 and the second electronic power module 5 powered by the onboard network 8 that are active, while the first electrical machine 2, the first electronic power module 4, and the stores 6 and 7 are not involved.

[0074] FIG. 4 shows an embodiment in which, in standby mode of the engine 1, both electric powertrains are active simultaneously, but each delivers a power of only Pv/2 equal to half the power Pv needed for standby mode, i.e. of the order of 1% to 3% of the total power Prr. The first and second electrical machines 2 and 3 and the first and second electronic power modules 4 and 5 are thus active simultaneously, both drawing power from the onboard network 8, while the stores 6 and 7 are not involved.

[0075] FIGS. 5 to 7 show how the normal reactivation mode or starting mode of the engine 1 can be performed by the two electric powertrains in three different embodiments.

[0076] In the first embodiment shown in FIG. 5, the energy corresponding to normal reactivation or mechanical power Pdem, which is typically of the order of 20% of the total power Prr needed for rapid reactivation, is taken from the onboard network 8 and only one electric powertrain is used.

[0077] FIG. 5 shows the electric powertrain comprising the first electrical machine 2 and the first electronic power module 4 powered by the onboard network 8 as being active, while the second electrical machine 3, the second electronic power module 5, and the stores 6 and 7 are not involved. In a following mission of the aircraft, the roles should be interchanged so that it is the second electrical machine 3 and the second electronic power module 5 powered by the onboard network 8 that are active, while the first electrical machine 2, the first electronic power module 4, and the stores 6 and 7 are not involved.

[0078] The embodiment of FIG. 6 is analogous to the embodiment of FIG. 5 insofar as only one electric powertrain is used, however the energy corresponding to normal reactivation or mechanical power Pdem, which is typically of the order of 20% of the total power Prr needed for rapid reactivation, is taken not from the onboard network 8, but from a store.

[0079] In FIG. 6, the electric powertrain comprising the first electrical machine 2 and the first electronic power module 4 powered by the store 6 is shown as being active, while the second electrical machine 3, the second electronic power module 5, the store 7, and the onboard network 8 are not involved in this operation. In a following mission of the aircraft, the roles should be interchanged so that it is the second electrical machine 3 and the second electronic power module 5 powered by the store 7 that are active, while the first electrical machine 2, the first electronic power module 4, the store 6, and the onboard network 8 are not involved.

[0080] Naturally, when the embodiment of FIG. 2 is used, the store 66 and the store 67 perform the same roles as the stores 6 and 7, respectively.

[0081] FIG. 7 shows an embodiment in which, in normal reactivation or starting mode of the engine 1, both electric powertrains are active simultaneously, but with each delivering power of only Pdem/2 equal to half of the power Pdem needed for standby mode, i.e. typically of the order of 20% of the total power Prr. The first and second electrical machines 2 and 3 and the first and second electronic power modules 4 and 5 are thus active simultaneously.

[0082] FIG. 7 shows connections indicating that energy is taken by the first and second electronic power modules 4 and 5 from the onboard network 8, while the stores 6 and 7 are not involved.

[0083] Nevertheless, in a variant, in the embodiment of FIG. 7, where both electric powertrains are active simultaneously, the first and second electronic power modules 4 and 5 could take energy corresponding to Pdem/2 from the stores 6 and 7 respectively (or 66 and 67 if the embodiment of FIG. 2 is being used) and not from the onboard network 8.

[0084] FIG. 8 shows an embodiment in which, in rapid reactivation mode of the engine 1, both electric powertrains are active simultaneously in simultaneous and coordinated operation, but each delivers power of only Prr/2 equal to half the total power Prr needed for rapid reactivation mode. The first and second electrical machines 2 and 3 and the first and second electronic power modules 4 and 5 are thus active simultaneously.

[0085] In the embodiment of FIG. 8, energy is taken by the first and second electronic power modules 4 and 5 firstly from the stores 6 and 7 (or 66 and 67 for the embodiment of FIG. 2), in equal shares for power of the order of Prr/2. Nevertheless, additional power, where necessary, may be taken by the first and second electronic power modules 4 and 5 from the onboard network 8.

[0086] FIG. 9 shows a configuration of the architecture of FIG. 1 in which a test is carried out by applying varying power Pvar, where Pvar can vary between almost zero power and power equal to half of the total power Prr, for each of the complete electric powertrains in order to guarantee proper operation and performance for the system.

[0087] The test is preferably carried out each time the propulsion system of the aircraft is started on the ground, but it can also be carried out in flight, should that be necessary.

[0088] The energy needed for testing proper operation may be supplied by the onboard network 8 or by the energy storage members 6, 7 or 66, 67, as required.

[0089] The tests may be performed in alternation or simultaneously on both electric powertrains.

[0090] By way of example, FIG. 9 shows the situation in which all of the branches of all of the electric powertrains are tested simultaneously with variable power Pvar that is thus delivered by the stores 6 and 7 and by the onboard network 8 to each of the electronic power modules 4 and 5.

[0091] The present invention provides various advantages over existing solutions, and in particular it makes it following possible: [0092] a spot reactivation test on every other mission for each electric powertrain by means of the starting procedure before each mission and alternating the use of the electric powertrains; [0093] a permanent test of the operation of the electric powertrain by means of the standby mode, which makes use of the electric powertrain(s) and which causes the electrical machines to rotate permanently while economic mode is in use; [0094] segregation between the electric powertrains is provided in particular for the energy storage portion by making use of two identical stores 6 and 7 that are physically dissociated and each suitable for storing half of the maximum required energy (Prr/2), or by using a single store 60 grouping together two identical stores 66 and 67 each suitable for storing half of the maximum required energy (Prr/2), these two identical stores 66 and 67 being in a single physical unit but being isolated from each other; [0095] redundancy for normal reactivation mode by having two independent electric powertrains; [0096] redundancy for the power supplies insofar as normal reactivation can be obtained either from a store 6, 7 or 66, 67 or from the onboard network 8, depending on the availability of these sources; and [0097] minimized and optimized dimensioning of the two electric powertrains that enable power from both electric powertrains to be added together in order to obtain the power needed for rapid reactivation (see FIG. 8).

[0098] In general, the invention is not limited to the embodiments described, but extends to any variant within the ambit of the scope of the accompanying claims.