Patent Application
20150246733
The present invention relates to the field of the supply of non-propulsive power for an aircraft, including the production of electrical and pneumatic power, affording the pressurisation and air-conditioning of a cabin for passengers on an aircraft. The temperature and pressure regulation of a passenger cabin is conventionally achieved by a system known to a person skilled in the art as an ECS, standing for “environmental control system”. When the main engines of the aircraft are stopped, the supply of pneumatic and/or electrical power is provided by an auxiliary power unit known to a person skilled in the art as an APU, standing for “auxiliary power unit”.
In a simplified manner, with reference to
In functioning, the ECS 1 takes the air AM from the main engines of the aircraft in order to set the load compressor 11 into rotation. The load compressor 11 aspirates ambient air Aamb via a supply valve 17 and compresses it in the heat exchanger 14 in order to regulate its temperature and then in the condenser 15 in order to dehumidify it. The cooled air flow then expands in the cold turbine 12 before being routed into the passenger cabin 2, as illustrated in
Optionally, after circulation in the passenger cabin 2, the air in the passenger cabin 2 can be introduced into a mixer 16 together with the ambient air Aamb, the mixture then being aspirated by the load compressor 11 in order to improve the efficiency of the ECS 1 by limiting the quantity of air AM taken from the main engines.
The ECS 1 taking power from the main engines is detrimental firstly to the fuel consumption of the aircraft and secondly to the configuration of the main engines, which must be able to cooperate with the ECS 1. In practice, for reasons of reliability, the ECS 1 is duplicated in an aircraft, which increases the constraints relating to the main engines.
With reference to
In order to eliminate at least some of these drawbacks, the invention relates to a method for supplying non-propulsive power for an aircraft, comprising the driving of a shaft of a system controlling the environment of the aircraft by a combination of energy sources selected from:
According to the invention, the environmental control system ECS can be activated by a plurality of energy sources, such as pneumatic and electrical sources. The auxiliary power unit APU may for example supply pneumatic energy (by delivering an air flow) and/or electrical energy (for example when it is equipped with a starter/generator). In a particular embodiment of the invention, the APU supplies pneumatic energy to the ECS and comprises a starter/generator that supplies electrical energy to a starter/generator of the ECS, in order to transmit a power boost to said ECS.
The starter/generator is able to supply electrical energy and the auxiliary-air supply means are able to supply pneumatic energy.
The invention thus makes it possible to operate the ECS according to a plurality of modes, which will be described in detail hereinafter.
The auxiliary power unit can generate an air flow driving a free turbine rigidly connected to the shaft of the environmental control system.
When functioning as starter, the starter/generator can be supplied with electricity by electrical supply means, such as electrical ground equipment of an airport, or the electrical system of the aircraft. In a variant or in addition, it may be supplied with electricity by a generator/starter of the auxiliary power unit.
The means for supplying auxiliary air may drive a free turbine rigidly connected to the shaft of the environmental control system. They may be formed by the main engines of the aircraft or by air-supply ground equipment of an airport.
The invention also relates to a device for supplying non-propulsive power for an aircraft, the device comprising:
The device according to the invention is self-contained and includes the functions of an auxiliary power unit APU, and also of an environmental control system ECS, which is advantageous.
Conventionally, an aircraft comprises an auxiliary power unit, known by the abbreviation APU, standing for “auxiliary power unit”, in order to supply pneumatic or electrical power to the equipment of the aircraft when said aircraft is on the ground and its turbojet engines are not in operation. During the flight of the aircraft, the APU is not used and is considered to be a “dead weight”.
Advantageously, the power unit and the environmental control system are coupled so as firstly to limit take-off from the main engines of the aircraft and secondly to fully use the capacities of the APU, which were traditionally used only at start-up. Furthermore, the APU makes it possible to supplement the supply of the ECS, which no longer needs to be necessarily duplicated. The efficiency of the aircraft is thus improved.
The APU and the ECS are traditionally considered to be distinct functional modules, that is to say devoid of interactions. This technical prejudice results in concrete terms in a clear differentiation in the specificities of aircraft constructors, who consider the APU and the ECS to belong to different and quite distinct functional classes. The APU and the ECS belong respectively to the functional classes ATA 49 and class ATA 21, well known to a person skilled in the art.
The invention is distinctive in that the known device further comprises at least one of the following energy sources:
The invention is particularly advantageous since it makes it possible to activate the environmental control system by means of a plurality of different sources, which may be used independently of one another or in combination with one another.
In a first case, the connecting shaft of the ECS may be set into rotation by (i) the APU or (ii) the starter/generator of the ECS, said starter/generator being able to be connected to electrical supply means.
In a second case, the connecting shaft for the ECS may be set into rotation by (i) the APU or (iii) the compressed air supply means.
In a third case, corresponding to the combination of the first two cases, the connecting shaft of the ECS may be set into rotation by (i) the APU, (ii) the starter/generator of the ECS or (iii) the compressed air supply means.
In other words, the invention proposes a device that is configured so as to be able to choose the activation source for the ECS from at least two available sources. This makes it possible to operate the device according to a plurality of modes, including:
Preferably, the non-propulsive power device is mounted in the same housing of an aircraft. Thus the cooperation between the APU and the ECS is not only functional but also physical in order to be able to reduce the space requirement of the regulation device while allowing a high-efficiency coupling.
Preferably, the power turbine and the free turbine are separated by a distance of less than 30 cm so as to allow an efficient pneumatic coupling.
Preferably, the auxiliary power unit comprises a starter/power generator suitable for setting the power shaft into rotation. Preferably again, the starter/power generator is suitable for generating electrical energy when the power turbine is rotated.
The starter/generator thus makes it possible to start the APU and to supply surplus electrical power to the ECS should additional compressed air be required. In addition, the starter/generator advantageously makes it possible to store electrical energy during the self-contained operating of the APU, which improves the energy efficiency of the regulation device.
Preferably, the secondary starter/generator of the environmental control system is electrically connected to the auxiliary power unit, preferably to the starter/power generator. Thus the secondary starter/generator makes it possible to supply surplus energy to the ECS according to compressed air requirements (referred to as operating mode T).
According to a preferred aspect of the invention, the regulation device comprises means for venting the free driving turbine so as to allow rotation of the free driving turbine when the ECS is supplied by auxiliary energy sources other than the auxiliary power unit.
Preferably, the free driving turbine is directly mounted in the vicinity of the load compressor on the connecting shaft, which makes it possible to limit the bulk and complexity of the ECS.
The invention further relates to a method for regulating an aircraft cabin for passengers, by means of a system as described above, in which the connecting shaft is driven by at least one of the following energy sources:
The invention will be better understood upon reading the following description, given solely by way of example, and referring to the accompanying drawings, in which:
It should be noted that the figures disclose the invention in detail for implementing the invention, said figures being able of course to serve to better define the invention where applicable.
The invention will be described for an aircraft comprising one or more main engines in order to move the aircraft. The aircraft further comprises a cabin for passengers that must be regulated for pressure and/or temperature. With reference to
The device 10 supplying non-propulsive power comprises an environmental control system 1, known to a person skilled in the art by the term ECS, and an auxiliary power unit 4, known to a person skilled in the art by the term APU. According to the invention, the ECS 1 and the APU 4 are coupled so that the APU 4 supplies power to the ECS unit 1 and thus reduces the power take-off thereof from the main engines of the aircraft.
ECS 1
As shown in
Preferably, the ECS 1 comprises a secondary starter/generator 18 mounted on the connecting shaft 13 of the ECS 1 so as to be able firstly to set the connecting shaft 13 into rotation when functioning as starter using its reserves of electrical energy, and, secondly, to accumulate electrical energy when the connecting shaft 13 is rotated when functioning as “generator”). Advantageously, when functioning as starter, the secondary starter/generator 18 makes it possible to precisely regulate the pressurised air supply to the passenger cabin 2.
In this example, the supply means 17 are in the form of a supply valve 17 but it goes without saying that other means could be suitable. Preferably again, the ECS 1 comprises a mixer 16 suitable for mixing the ambient air flow Aamb from the supply valve 17 with an air flow from the passenger cabin 2. Such a recirculation of the air flow from the passenger cabin 2 makes it possible to advantageously improve the efficiency of the ECS 1.
APU 4
Still with reference to
Preferably, the APU 4 comprises a starter/power generator 46 mounted on the power shaft 43 of the APU 4 so as to be able firstly to set the power shaft 43 into rotation when functioning as “starter” using its electrical energy reserves, and secondly to accumulate electrical energy when the power shaft 43 is rotated.
Preferably, the starter/power generator 46 is mounted on the power shaft 43 by means of a relay box 45, that is to say a multiplier, so as to adapt the rotation speed of the power shaft 43 to that of the starter/power generator 46. Thus the starter/power generator 46 can be driven by the power shaft 43 in order to generate electrical energy or drive the power shaft 43, that is to say generate mechanical energy from electrical energy.
According to one aspect of the invention, the secondary starter/generator 18 of the ECS 1 is electrically connected to the APU 4, preferably to the starter/power generator 46 thereof, so as to allow electrical driving of the connecting shaft 13 of the ECS 1, as will be detailed below. Moreover, the secondary starter/generator 18 of the ECS 1 can also be electrically connected to electrical ground equipment of an airport, as will be detailed hereinafter.
As the APU and the ECS each have a starter/generator 18, 46, the speed of each shaft can be freely regulated in order to adapt reactively to the requirements of the non-propulsive power supply device 10.
Conventionally, such an APU 4 is used only during phases on the ground, that is to say before the main engines of the aircraft are actually started, and after stoppage thereof. The APU 4 and ECS 1 are conventionally separate devices that do not interact with each other when the aircraft is in flight. According to the invention, the APU 4 and the ECS 1 cooperate during a flight of the aircraft in order to limit the times when power is taken from the main engines of the aircraft and thus increase the energy efficiency of the aircraft. In addition, this makes it possible to form a device of limited size and mass.
According to the invention, the ECS 1 comprises a free driving turbine 5 rigidly connected to the connecting shaft 13 as shown in
The air expelled from the combustion chamber 44 of the APU 4 expands in the power turbine 42 and then in the free turbine 5 as shown in
Preferably, the non-propulsive power supply device 10 comprises means 63 for supplying auxiliary air Aaux to the free turbine 5. Auxiliary air Aaux means an air flow, for example from the main engines of the aircraft or supplied by ground equipment of an airport. In this example, the means 63 supplying auxiliary air Aaux are in the form of a supply valve. Preferably, the regulation device 10 comprises means 64 for venting the free turbine 5 when the APU 4 is not activated. In this example, the venting means 64 are in the form of a venting valve.
Preferably again, the non-propulsive power supply device 10 comprises a mixer 62 arranged so as to mix an air flow from the means 63 supplying auxiliary air Aaux, an air flow from the venting means 64 and an air flow AAPU from the power turbine 42. Preferably, the non-propulsive power supply device 10 comprises means 61 for regulating the air flow AAPU supplied by the power turbine 42 to the mixer 62, preferably a regulation valve.
The invention intends to combine the APU 4 and the ECS 1 in order to form a non-propulsive power supply device 10 having low mass and limited bulk.
According to one aspect of the invention, the APU 4 and the ECS 1 belong to the same housing in the aircraft, the housing being able to be a single unit or compartmented. Preferably, the power turbine 42 of the APU 4 and the free turbine 5 of the ECS 1 are separated by a distance of less than 30 cm, preferably of approximately 5 cm. The proximity of the power turbine 42 of the APU 4 to the free turbine 5 of the ECS 1 makes it possible to effectively profit from the expansion of the gases from the combustion chamber 44 of the APU. Preferably, the free driving turbine 5 is directly mounted in the vicinity of the load compressor 11 on the connecting shaft 13, that is to say without any intermediary, so as to limit the bulk and complexity of the non-propulsive power supply device 10.
The invention will be better understood with reference to
Self-Contained Operating (MODE-A)
With reference to
The load compressor 11 aspirates external air Aamb via the supply means 17, which air is conducted and compressed in the exchanger 14 and cooled by an external air flow Aext. Once cooled, the air flow is dried by the condenser 15 before being expanded in the distribution turbine 12 in order then to be conducted into the passenger cabin 2. Recirculated air from the passenger cabin 2 can also be taken off by the load compressor 11. The mixer 16 can also adapt to the proportion of ambient air Aamb in the air aspirated by the load compressor 11.
Advantageously, during MODE-A, the starter/power generator 46 of the APU 4, after having served for starting the assembly, can supply electrical energy by means of the relay box 45. Preferably, the starter/power generator 18 of the ECS 1 can also supply electrical energy.
In this example, the auxiliary-air supply means 63 and the venting means 64 are closed.
In self-contained operating MODE-A, the ECS 1 is supplied pneumatically by the APU 4. This pneumatic energy is transformed by the free driving turbine 5 into a rotation of the connecting shaft 13. The APU is thus used during the starting of the aircraft but also during flight.
Operating with Transfer of Electrical Energy (MODE-T)
With reference to
Advantageously, during MODE-T, the starter/power generator 46 electrically supplies the secondary starter/generator 18 of the ECS 1 so as to accelerate the driving speed of the connecting shaft 13. In other words, if the ECS 1 requires, for particular conditions, a large amount of energy, the starter/power generator 46 can supply electrical energy, which supplements the pneumatic energy supplied by the power turbine 42, which is highly advantageous. The connecting shaft 13 thus receives a temporary power boost, which is advantageous in the flight phases of the aircraft where the pressurised air requirements are high (so-called “pull-up” or “pull-down” phases).
In this example, the auxiliary-air supply means 63 and the venting means 64 are closed.
In self-contained operating MODE-A, the ECS 1 is supplied pneumatically and electrically by the APU 4. Advantageously, it is not necessary to oversize the non-propulsive power supply device 10 in order to respond to transient forces, the surplus electrical energy supplied by the APU 4 making it possible to absorb the transient forces.
Electrical Operating (MODE-E)
With reference to
Thus, during operating in electrical mode, the connecting shaft 13 is driven by the auxiliary electrical source Eaux. Since the free driving turbine 5 is rigidly connected to the connecting shaft 13, it is important to vent the free driving turbine 5 in order to prevent any malfunctioning in the absence of air supply to the APU 4. To this end, the venting valve 64 is open in electrical operating while the auxiliary-air supply means 63 remain closed.
In electrical operating MODE-E, the ECS 1 is supplied electrically by an auxiliary electrical source Eaux, which is advantageous and does not take resources particular to the aircraft.
Pneumatic Operating (MODE-P)
With reference to
Thus, during operating in pneumatic mode, the free driving turbine 5 is driven by the auxiliary pneumatic source Aaux. For this purpose, the auxiliary-air supply means 63 are open in pneumatic operating while the venting means 64 remain closed.
In pneumatic operating MODE-P, the ECS 1 is supplied pneumatically by an auxiliary pneumatic source Aaux. This pneumatic power source may be external to the aircraft (ground equipment of an airport for example) or come from a compressed air source integrated in the aircraft (main engines, cabin pressurisation recovery, etc.).
| Number | Date | Country | Kind |
|---|---|---|---|
| 1258682 | Sep 2012 | FR | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/FR2013/052072 | 9/10/2013 | WO | 00 |
