ARCHITECTURE FOR A PROPULSION SYSTEM OF A HELICOPTER INCLUDING A HYBRID TURBOSHAFT ENGINE AND A SYSTEM FOR REACTIVATING SAID HYBRID TURBOSHAFT ENGINE

Abstract

The invention relates to an architecture of a propulsion system of a multi-engine helicopter comprising turboshaft engines connected to a power transmission gearbox, characterised in that it comprises: at least one hybrid turboshaft engine (20) capable of operating in at least one standby mode during a stable cruise flight of the helicopter; at least two systems (30; 40) for controlling each hybrid turboshaft engine (20), each system (30; 40) comprising an electric machine (31; 41) connected to the hybrid turboshaft engine (20) and suitable for rotating the gas generator thereof, and at least one source (33; 43) of electrical power for said electric machine (31; 41), each reactivation system (30; 40) being configured such that it can drive said turboshaft engine (20) in at least one operating mode among a plurality of predetermined modes.

Claims

1. Architecture of a propulsion system of a multi-engine helicopter having turboshaft engines connected to a power transmission gearbox, the architecture comprising: a hybrid turboshaft engine among said turboshaft engines, the hybrid turboshaft engine capable of operating in at least one standby mode during a stable cruise flight of the helicopter, the other turboshaft engines operating alone during the stable cruise flight; at least two reactivation systems configured to control the hybrid turboshaft engine, each reactivation system comprising an electric machine connected to the hybrid turboshaft engine for rotating said hybrid turboshaft engine, and at least one source of electrical power for said electric machine, each reactivation system configured to drive said hybrid turboshaft engine in at least one operating mode among a plurality of predetermined modes.

2. Architecture according to claim 1, wherein the hybrid turboshaft engine further comprises a gas generator, and wherein said plurality of predetermined modes comprises: a rapid reactivation mode, wherein said hybrid turboshaft engine is rotated up to a speed in the range of between 80 and 105% of a nominal speed of said gas generator of said hybrid turboshaft engine in a period of less than 10 seconds; a normal reactivation mode, wherein said hybrid turboshaft engine is rotated up to a speed in the range of between 80 and 105% of said nominal speed of said gas generator of said hybrid turboshaft engine in a period in the range of between 10 seconds and 60 seconds; an assisted super-idle standby mode, in which the hybrid turboshaft engine is rotated continuously at a speed in the range of between 20 and 60% of said nominal speed of said gas generator of said hybrid turboshaft engine; a turning standby mode, in which said gas generator of said hybrid turboshaft engine is rotated continuously at a speed in the range of between 5 and 20% of said nominal speed.

3. Architecture according to claim 2, wherein each reactivation system is configured to drive said gas generator of said hybrid turboshaft engine in said rapid reactivation mode and comprises a source of electrical power formed by an energy storage unit; and wherein each reactivation system is configured to drive said gas generator of said hybrid turboshaft engine in said normal reactivation mode, said assisted super-idle standby mode, or said turning standby mode and comprises a source of electrical power formed by an onboard network of the helicopter.

4. Architecture according to claim 3, wherein said onboard network is a network configured to supply a compatible AC voltage of the helicopter.

5. Architecture according to claim 2, wherein: a first reactivation system of said at least two reactivation systems is configured to drive said hybrid turboshaft engine in the rapid reactivation mode the normal reactivation mode, and at least one of the assisted super-idle standby mode and the turning standby mode; and a second reactivation system of said at least two reactivation systems is configured to drive said hybrid turboshaft engine solely in said normal reactivation mode.

6. Architecture according to claim 5, wherein said second reactivation system is configured to drive the hybrid turboshaft engine in said rapid reactivation mode.

7. Architecture according to claim 1, wherein: a first reactivation system of said at least two reactivation systems is configured to drive said hybrid turboshaft engine in both the rapid reactivation mode and the normal reactivation mode; and a second reactivation system of said at least two reactivation systems is configured to drive said hybrid turboshaft engine solely in said standby mode.

8. Architecture according to claim 7, wherein said second reactivation system is configured to drive the hybrid turboshaft engine in said normal reactivation mode.

9. A multi-engine helicopter having turboshaft engines connected to a propulsion system, the helicopter comprising: a hybrid turboshaft engine among said turboshaft engines, the hybrid turboshaft engine capable of operating in at least one standby mode during a stable cruise flight of the helicopter, the other turboshaft engines operating alone during the stable cruise flight at least two reactivation systems for controlling the hybrid turboshaft engine, each reactivation system comprising an electric machine connected to the hybrid turboshaft engine for rotating said hybrid turboshaft engine, and at least one source of electrical power for said electric machine, each reactivation system configured to drive said hybrid turboshaft engine in at least one operating mode among a plurality of predetermined modes.

10. The helicopter according to claim 9, wherein each hybrid turboshaft engine further comprises a gas generator, and wherein said plurality of predetermined modes comprises: a rapid reactivation mode, wherein said hybrid turboshaft engine is rotated up to a speed in the range of between 80% and 105% of a nominal speed of said gas generator of said hybrid turboshaft engine in a period of less than 10 seconds; a normal reactivation mode, wherein said hybrid turboshaft engine is rotated up to a speed in the range of between 80% and 105% of said nominal speed of said gas generator of said hybrid turboshaft engine in a period in the range of between 10 seconds and 60 seconds; an assisted super-idle standby mode, in which the hybrid turboshaft engine is rotated continuously at a speed in the range of between 20% and 60% of said nominal speed of said gas generator of said hybrid turboshaft engine; a turning standby mode, in which said gas generator of said hybrid turboshaft engine is rotated continuously at a speed in the range of between 5% and 20% of said nominal speed.

11. The helicopter according to claim 10, wherein each reactivation system is configured to drive said gas generator of said hybrid turboshaft engine in said rapid reactivation mode and comprises a source of electrical power formed by an energy storage unit; and wherein the reactivation system is configured to drive said gas generator of said hybrid turboshaft engine in said normal reactivation mode, said assisted super-idle standby mode, or said turning standby mode and comprises a source of electrical power formed by an onboard network of the helicopter.

12. The helicopter according to claim 11, wherein said onboard network is a network configured to supply a compatible AC voltage of the helicopter.

13. The helicopter according to claim 10, wherein: a first reactivation system of said at least two reactivation systems is configured to drive said hybrid turboshaft engine in the rapid reactivation mode, the normal reactivation mode, and at least one of the assisted super-idle standby mode and the turning standby mode; and a second reactivation system of said at least two reactivation systems is configured to drive said hybrid turboshaft engine solely in said normal reactivation mode.

14. The helicopter according to claim 13, wherein said second reactivation system is configured to drive the hybrid turboshaft engine in said rapid reactivation mode.

15. The helicopter according to claim 10, wherein: a first reactivation system of said at least two reactivation systems is configured to drive said hybrid turboshaft engine in both the rapid reactivation mode and the normal reactivation mode; and a second reactivation system of said at least two reactivation systems is configured to drive said hybrid turboshaft engine solely in said standby mode.

16. The helicopter according to claim 15, wherein said second reactivation system is configured to drive the hybrid turboshaft engine in said normal reactivation mode.

Description

5. LIST OF FIGURES

[0050] Other aims, features and advantages of the invention will become apparent upon reading the description that follows, which is given purely by way of non-limiting example and relates to the accompanying figures, in which:

[0051] FIG. 1 is a schematic view of an architecture from the prior art comprising a turboshaft engine controlled by a single control system;

[0052] FIG. 2 is a schematic view of another architecture from the prior art;

[0053] FIG. 3 is a schematic view of an architecture according to an embodiment of the invention;

[0054] FIG. 4 is a schematic view of an architecture according to another embodiment of the invention;

[0055] FIG. 5 is a schematic view of an architecture according to another embodiment of the invention;

[0056] FIG. 6 is a schematic view of an architecture according to another embodiment of the invention;

[0057] FIG. 7 is a schematic view of an architecture according to another embodiment of the invention.

6. DETAILED DESCRIPTION OF SOME EMBODIMENTS OF THE INVENTION

[0058] The embodiments described below are some examples for carrying out the invention. Although the detailed description refers to one or more embodiments, this does not necessarily mean that each reference relates to the same embodiment, or that the features apply only to a single embodiment. Individual features of different embodiments can also be combined in order to provide other embodiments. In addition, in the figures, for the purposes of illustration and clarity, the scales and the proportions are not necessarily accurate.

[0059] FIG. 1 is a schematic view of an architecture of a known helicopter propulsion system comprising a turboshaft engine 10 and a system for controlling said turboshaft engine. The control system comprises an electric machine 11 suitable for rotating the turboshaft engine 10 on demand so as to ensure the start-up thereof. The electric machine 11 draws its power directly from a low-voltage onboard network 12 of the helicopter, which is typically a network that supplies a 28-volt DC voltage.

[0060] FIG. 2 is a schematic view of an architecture of a known helicopter propulsion system comprising the turboshaft engine 10 and another system for controlling said turboshaft engine. The control system comprises an electric machine 11 suitable for rotating the turboshaft engine 10 on demand so as to ensure the start-up thereof. The electric machine 11 draws its power from a compatible high AC-voltage onboard network 14 of the aircraft. The control system also comprises a power conversion module 13 designed to convert the high AC voltage supplied by the onboard network 14 into a voltage for controlling the electric machine 11.

[0061] The turboshaft engine 10 having the architectures from FIGS. 1 and 2 is generally started on the ground. An in-flight restart of a turboshaft engine according to this architecture is an exceptional event.

[0062] FIGS. 3 to 7 show architectures according to the invention that allow at least one turboshaft engine to be put on standby and to be reactivated during flight. In addition, the proposed architectures make the reactivation operations reliable and allow the different reactivation systems to be tested regularly.

[0063] In FIGS. 3 to 7, only the hybrid turboshaft engine is shown, it being understood that in a multi-engine architecture, in particular a twin-engine or three-engine architecture, the architecture comprises a plurality of turboshaft engines of which at least one is a hybrid turboshaft engine.

[0064] An architecture according to the invention comprises a plurality of turboshaft engines connected to a power transmission gearbox (not shown in the figures).

[0065] Among the plurality of turboshaft engines, at least one turboshaft engine, referred to as a hybrid turboshaft engine 20, is capable of operating in at least one standby mode during a cruise flight of the helicopter.

[0066] According to the embodiments shown in FIGS. 3 to 7, the architecture comprises two systems 30, 40 for reactivating the hybrid turboshaft engine 20. In the whole of the following, the reactivation system denoted by reference numeral 30 will be referred to as the first reactivation system and the reactivation system denoted by reference numeral 40 will be referred to as the second reactivation system.

[0067] It is also hereby specified that the same reference numerals 30 and 40 are used to indicate the first and second reactivation systems in FIGS. 3 to 7, even though the reactivation systems may not be the same from one embodiment to another.

[0068] Each reactivation system 30, 40 is configured to be capable of driving the turboshaft engine 20 in at least one operating mode among a plurality of predetermined modes.

[0069] In light of the turboshaft engine comprising a gas generator, the predetermined modes comprise at least the following modes: [0070] a mode, referred to as the rapid reactivation mode, in which the turboshaft engine 20 is rotated from the standby mode up to a speed in the range of between 80 and 105% of the nominal speed of the gas generator of the turboshaft engine within a period of less than 10 seconds; [0071] a mode, referred to as the normal reactivation mode, in which the turboshaft engine 20 is rotated from the standby mode up to a speed in the range of between 80 and 105% of the nominal speed of the gas generator of the turboshaft engine within a period in the range of between 10 seconds and 60 seconds; [0072] a standby mode, referred to as the assisted super-idle mode, in which the turboshaft engine 20 is continuously rotated at a speed in the range of between 20 and 60% of the nominal speed of the gas generator of the turboshaft engine; [0073] a standby mode, referred to as the turning mode, in which the turboshaft engine 20 is continuously rotated at a speed in the range of between 5 and 20% of said nominal speed.

[0074] In FIG. 3, the first reactivation system 30 comprises an electric machine 31, a power conversion device 32, an electrical energy storage unit 33, and an onboard network 51. The second reactivation system 40 comprises an electric machine 41, a power conversion device 42 and an onboard network 51, which is shared with the first reactivation system 30.

[0075] This embodiment allows the first reactivation system 30 to drive the turboshaft engine 20 in any of the rapid reactivation mode (by the use of the energy from the storage unit 33), the normal reactivation mode (by the use of the energy from the onboard network 51 or from the storage unit 33), or at least one standby mode (by the use of the energy from the onboard network 51). It also allows the second reactivation system 40 to be capable of driving the turboshaft engine 20 in said normal reactivation mode (by the use of the energy from the onboard network 51).

[0076] According to this embodiment, the first and second systems can be called upon alternately at each start-up to check their availability.

[0077] Since the first system is also configured for a rapid reactivation and a standby mode, the transition of the turboshaft engine 20 into standby mode allows the integrity of the system 30 to be tested and therefore any malfunction then preventing rapid reactivation of the turboshaft engine 20 by the system 30 to be detected. In the event of a malfunction being detected, the second system 40 is then called upon for a normal reactivation of the hybrid turboshaft engine 20.

[0078] During a rapid reactivation of the hybrid turboshaft engine 20 by the first reactivation system 30, the second system 40 can also potentially provide additional power if necessary.

[0079] The architecture shown in FIG. 4 is a variant of that shown in FIG. 3. This architecture comprises, in addition to the elements described in relation to FIG. 3, a second storage unit 43 arranged in the second reactivation system 40.

[0080] This embodiment therefore allows the second reactivation system 40 to also drive the turboshaft engine 20 in the rapid reactivation mode (by the use of the energy from the storage unit 43).

[0081] This architecture is therefore redundant and has a high degree of availability.

[0082] In FIG. 5, the first reactivation system 30 comprises an electric machine 31, a power conversion device 32, an electrical energy storage unit 33, and an onboard network 51 that is, for example, an onboard network supplying an AC voltage of 115 volts. The second reactivation system 40 comprises an electric machine 41, a power conversion device 42, an onboard network 52 that is, for example, a network supplying a DC voltage of 28 volts, the onboard network 51 shared with the first reactivation system 30, and optionally an electrical energy storage unit 53.

[0083] In this embodiment, the first reactivation system 30 allows the turboshaft engine 20 to be driven in the rapid reactivation mode (by the use of the energy from the storage unit 33), in the normal reactivation mode (by the use of the energy from the onboard network 51 or from the storage unit 33) or in a standby mode. It also allows the second reactivation system 40 to be capable of driving the turboshaft engine 20 in a normal reactivation mode (by the use of the energy from the onboard network 52 or from the optional storage unit 53 or by the energy from the onboard network 51). In particular, this particular configuration allows the second system 40 for reactivating the turboshaft engine 20 to use the onboard network 51 for high power levels, for example levels greater than 10 kW, and to use the onboard network 52 for lower power levels, for example levels below 10 kW.

[0084] In FIG. 6, the first reactivation system 30 comprises an electric machine 31, a power conversion device 32 and an electrical energy storage unit 33. The second reactivation system 40 comprises an electric machine 41, a power conversion device 42 and an onboard network 51.

[0085] In this embodiment, the first reactivation system 30 allows the turboshaft engine 20 to be driven in the rapid reactivation mode (by the use of the energy from the storage unit 33). It also allows the second reactivation system 40 to be capable of driving the turboshaft engine 20 in a standby mode (by the use of the energy from the onboard network 51) or in a normal reactivation mode.

[0086] In FIG. 7, the first reactivation system 30 comprises an electric machine 31, a power conversion device 32, an electrical energy storage unit 33, and an onboard network 51. The second reactivation system 40 comprises an electric machine 41, a power conversion device 42 and the onboard network 51, shared with the first system 30.

[0087] In this embodiment, the first reactivation system 30 allows the turboshaft engine 20 to be driven in the rapid reactivation mode (by the use of the energy from the storage unit 33) and in the normal reactivation mode (by the use of the energy from the onboard network 51 or from the storage unit 33). It also allows the second reactivation system 40 to be capable of driving the turboshaft engine 20 in a standby mode or in a normal reactivation mode (by the use of the energy from the onboard network 51).

[0088] In a variant, the second system can be configured to drive the turboshaft engine 20 solely in a standby mode (by the use of the energy from the onboard network 51).

[0089] The advantage of this architecture is the ability to use power-optimised electric machines, in particular for the electric machine 41, the only function of which is to provide the standby mode.

[0090] For each mode, the control of the reactivation systems is governed by the turboshaft engine control system known by the acronym FADEC, for Full Authority Digital Engine Control.

[0091] The invention is not limited solely to the embodiments described. In particular, the invention may comprise a plurality of hybrid turboshaft engines, each turboshaft engine being provided with at least two reactivation systems of its own as described.