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CN-116568596-B - Hybrid propulsion system for helicopter

CN116568596BCN 116568596 BCN116568596 BCN 116568596BCN-116568596-B

Abstract

A propulsion system (2) for a helicopter (1) is disclosed, comprising a main engine (9), a main rotor (3), a main gearbox (4) comprising an output mechanically connected to the main rotor (3), a reduction gearbox (13) mechanically coupled between the main engine (9) and a first input of the main gearbox (4), and an auxiliary device (10). The auxiliary device (10) comprises a first electric machine mechanically coupled to the reduction gearbox (13) and configured to act as a generator to remove energy generated by the main engine (9), and a second electric machine mechanically coupled to a second input of the main gearbox (4), the second electric machine being supplied with electric power by the first electric machine and configured to act as an electric motor to deliver additional mechanical power to the main gearbox (4).

Inventors

  • Roman Jean Gilbert Tirier
  • Fabian Messir Karwa, Iraq
  • Stefana Albert Andre Duale

Assignees

  • 赛峰直升机发动机

Dates

Publication Date
20260505
Application Date
20211203
Priority Date
20201211

Claims (10)

  1. 1. A propulsion system (2) for a helicopter (1) comprises a main engine (9), a main rotor (3), an electronic control unit (23), a main gearbox (4) comprising an output mechanically connected to the main rotor (3), a reduction gearbox (13) mechanically coupled between the main engine (9) and a first input (41) of the main gearbox (4), and auxiliary equipment (10), Wherein the auxiliary device (10) comprises a first electric machine (21 ') and a second electric machine (22), the first electric machine (21 ') being mechanically coupled to the reduction gearbox (13) and configured to operate as a generator to remove energy generated by the main engine (9), the second electric machine (22) being mechanically coupled to a second input (42) of the main gearbox (4) via a gear train, the second electric machine (22) being supplied with electric power by the first electric machine (21 ') and configured to operate as an electric motor to deliver additional mechanical power to the main gearbox (4) when needed, and Wherein the mechanical coupling of the first motor to the reduction gearbox is independent of the mechanical coupling of the reduction gearbox to the main engine, The main engine (9) comprises an output shaft (12) driven by a power turbine (16) of the main engine and mechanically connected to a reduction gearbox (13), and the first electric motor (21') comprises a rotor and a stator (210), the rotor being formed by an electromagnetic part of the output shaft (12) of the main engine (9), and the stator (210) being mounted around said electromagnetic part of the output shaft of the main engine (9), and The electronic control unit (23) is configured to control an output torque of the main engine.
  2. 2. Propulsion system (2) according to claim 1, wherein the electronic control unit (23) is electrically coupled to the first and second electric machines (21 ', 22) and configured to control the operation of the first and second electric machines (21', 22) depending on the available output torque of the main engine (9) and the output torque required by the main gearbox (4).
  3. 3. A propulsion system (2) according to claim 2, wherein the electronic control unit (23) comprises a measuring member (26), the measuring member (26) being configured to continuously measure the instantaneous torque at the first input (41) of the main gearbox (4), and the electronic control unit being configured to control the operation of the first electric machine (21, 21') to supply power to the second electric machine (22) when the instantaneous torque measured by the measuring member (26) is smaller than the output torque required by the main gearbox (4), and to command an increase of the operating speed of the main engine (9) to supply additional energy required by the electric power supply of the second electric machine (22).
  4. 4. A propulsion system (2) according to claim 2, wherein the electronic control unit (23) is configured to control the operation of the first and second motors (21', 22) to compensate for the lack of output power of the main gearbox (4) when the main rotor (3) is operated at a speed lower than the nominal speed in a flight phase in which the main rotor (3) is required to operate at its nominal speed.
  5. 5. Propulsion system (2) according to claim 1, wherein the reduction gearbox (13) is a planetary reduction gearbox coupled to the main engine (9), the first electric machine (21') and the main gearbox (4) simultaneously.
  6. 6. The propulsion system (2) according to claim 1, further comprising an overrunning clutch (14) coupled to the output of the reduction gearbox (13), a rear propeller shaft (8) coupled between the overrunning clutch (14) and the counter torque rotor (7), and a front propeller shaft (5) coupled between the first input (41) of the main gearbox (4) and the overrunning clutch (14).
  7. 7. A helicopter comprising a propulsion system (2) according to claim 1.
  8. 8. A method for assisting a system for a propulsion system (2) of a helicopter (1) according to claim 1, the method comprising requesting activation of energy taken from a main engine (9) of the propulsion system (2) by means of a command to operate a first electric machine (21') as a generator, the activation request being a result of a decision depending on at least one specific condition verified by a pilot of the helicopter, or by a control computer of the main engine, or by avionics of the helicopter.
  9. 9. Auxiliary method according to claim 8, wherein the activation requirement is the result of a decision by the control computer of the main engine when it detects that the operating point of the main engine (9) is within a set of predetermined operating points for which the operating state of the main engine is below a percentage threshold value of the nominal operating speed of the main engine and acceleration transients returning to a faster speed than said percentage threshold value are considered too long compared to the desired dynamics of the main engine and helicopter, and wherein the activation requirement is accompanied by a command for increasing the operating speed of the main engine such that the duration of possible acceleration transients is reduced to correspond to said desired dynamics.
  10. 10. The auxiliary method of claim 9, wherein the percentage threshold of nominal operating speed of the main engine is between 80% and 85%.

Description

Hybrid propulsion system for helicopter Technical Field The present invention relates to the general field of helicopter propulsion systems and more particularly to the field of hybrid propulsion systems for helicopters, in particular helicopters known as single-engine helicopters. Background A single engine helicopter is a helicopter comprising a propulsion system comprising a single main engine, typically an internal combustion engine, and for example a turbine engine, for driving the main rotor via a main gearbox called MGB and the rear tail rotor (also called the acronym ATR for anti-torque rotor) via a rear gearbox called RGB. The propulsion system may also include a device for assisting the helicopter. Auxiliary equipment is used in emergency situations to instantaneously power the helicopter and, more precisely, to power the main and rear rotors. The first emergency is a main engine failure. In this case, the pilot then initiates a degraded flight mode, known as autorotation. The auxiliary device allows mechanically assisting the helicopter during the autorotation flight, in particular during the first and/or last phases of the flight (the "leveling" is completed before landing). Thus, this type of auxiliary device may significantly assist the pilot in completing a spinning landing. The second emergency is for example the immediate need for additional power during obstacle avoidance or high altitude temperature reversal. Different architectures for integrating auxiliary devices are known from document FR3 019 588. The auxiliary device includes a turbine powered by a gas generator having solid state storage for driving the shaft to rotate, and a controlled component for powering the driving turbine. In this case, the mechanical rotary power of the shaft is used to drive the main rotor of the helicopter by introducing this power directly at the MGB, or at the front propeller shaft, or at the shaft of the free turbine of the turbine engine (main engine). Such propulsion systems can cause a volume problem. In fact, the integration of this type of auxiliary equipment into an already very compact nacelle can produce considerable changes to the fuselage of the helicopter and at the main engine and in the power transmission between the main engine and the MGB. Furthermore, there are several disadvantages to introducing such power on the free turbine of the main turbine engine. The first disadvantage is that in the event of a failure of the gas supply to the free turbine of the main turbine engine, it does not generate drive torque and it decelerates very rapidly under the influence of aerodynamic friction losses. These losses can reach tens of kilowatts (kW). It will thus be appreciated that depending on the application example mentioned above, i.e. the main engine is malfunctioning or additional power is immediately required to avoid the obstacle, the driving power effectively seen by the main rotor is different, which may be surprising to the pilot of the helicopter. A second drawback is that when auxiliary power is injected via the free turbine, it is not possible to supply such auxiliary power to the main gearbox and the rear gearbox in case of failure of the free turbine and/or of a mechanical downstream component of the turbine engine (and in particular of the reduction gearbox of a turbine engine equipped with a reduction gearbox of this type). A third disadvantage is the need to provide specific interfaces on the turbine engine to allow such auxiliary power to be injected onto the free turbine. Furthermore, the power of the turbine engine of the helicopter is thermodynamically limited, and also mechanically limited, since the mechanical torque transmitted to the main rotor of the helicopter passes through the reduction gearbox and through the main gearbox. When the ambient temperature and altitude are low, it is well known that the power that is input via the MGB is limited by design to torque values that must not be exceeded continuously. Thus, when the rotational speed of the rotor of the helicopter is reduced, for example in order to limit acoustic pollution, the power delivered to the rotor is reduced proportionally. On the other hand, when the temperature and altitude are high, the power delivered by the helicopter turbine engine may be limited by the thermodynamic power of the free turbine. From document FR3 062 882 a propulsion system of a single-engine helicopter is known, comprising a main engine connected to a front and a rear drive shaft, which are capable of driving the MGB and the RGB, respectively, an auxiliary device fixed to the main engine and allowing to mechanically drive the RGB and the MGB by introducing power on said rear drive shaft. However, the auxiliary devices described in this document use auxiliary energy sources such as pyrotechnic and/or electrical and/or hydraulic and/or pneumatic components. The auxiliary energy source forms an additional element to be integrated into