Adjustment system for aircraft

Abstract

The invention relates to an adjustment system for an aircraft. In particular, the present invention pertains to a regulating system having a pressure accumulator connected to a heat recovery circuit and to a fuel conduit. The invention also relates to an aircraft comprising said adjustment system.

Description

Technical Field

[0001] The invention relates to a regulating system for an aircraft. In particular, the invention relates to a regulating system having a pressure accumulator connected to a heat recovery circuit and a fuel line. The invention also relates to an aircraft comprising said regulating system. Background Art

[0002] Auxiliary Power Unit or APU is well known in the field of aviation technology, as it is an engine capable of supplying energy to an aircraft for functions not considered as propulsion functions. APUs are usually found in large aircraft and are located at or near the tail cone portion of these aircraft.

[0003] A typical APU generally includes a power section which is the power generation section of the APU, a load compressor section which provides pneumatic power to the aircraft, and a gearbox section which is responsible for transferring power from the main shaft of the engine to the generator for electrical power. APUs are also known to allow aircraft to be independent of external electrical and pneumatic power sources both on the ground and in flight.

[0004] In addition, auxiliary power units in an aircraft can be used to replace the main engines when they are not operating while the aircraft is on the ground. The APUs also maintain temporary power to start the main engines during normal operation, they can be used to replace the power generated by the main engines when they fail under dispatch conditions, or continue to be implemented to supply emergency power until the aircraft lands.

[0005] The known problems of hydrogen engines are based on conditioning the hydrogen fuel to ambient temperature and the correct pressure in order to supply the engines of the APU in the right conditions and also to ensure safe combustion, avoiding damage to the different components and pipes of the auxiliary power unit. Due to the storage conditions of hydrogen in the field of aviation technology of about 20K, hydrogen is a fuel that requires specific dimensions and specific operating conditions of the systems that consume this type of fuel.

[0006] Furthermore, an additional known problem with using hydrogen for engines in aircraft is due to phase changes, since the hydrogen is in a liquid phase when stored in the aircraft before being supplied to the engines. However, in order for the engines of the APU to work optimally, the liquid hydrogen must undergo a phase change from liquid to gas. These phase changes also require that the system be designed and dimensioned so that the hydrogen remains stable as its conditions (temperature, pressure, etc.) change throughout the auxiliary power system.

[0007] However, new regulation systems have recently been provided for allowing, when implemented in an aircraft, the recycling of the heat generated by the hydrogen engines, more particularly the heat generated from the exhaust gases, and for dimensioning said systems according to the specific conditions of the aircraft, as well as new regulation systems capable of maintaining the hydrogen in its optimal state during any flight or ground operation of the aircraft.

[0008] On the other hand, and with regard to hydraulic energy storage and absorption, various forms of accumulators are known to perform these specific functions of storing and absorbing hydraulic energy in a hydraulic circuit.

[0009] When storing energy, the accumulator receives pressurized hydraulic fluid for later use. Sometimes the accumulator flow is added to the pump flow to speed up the process. Other times, the stored energy is held as a reserve until it is needed and can be independent of the pump flow. This can be used for emergency power when pump flow is unavailable. When pump flow stops, it can be used to maintain pressure in the system by providing fluid to compensate for leaks.

[0010] There are several ways in which accumulators are used to absorb energy. The return flow from a large bore cylinder may be greater than the flow that the lines should direct. A low pressure accumulator can receive a portion of the flow and then discharge it at a rate suitable for the lines. Hydraulic fluid has a relatively high rate of thermal expansion. If a volume of fluid is restricted and cannot expand or contract due to temperature changes, there may be very high pressures that could damage equipment or low pressures that could cause bubbles to appear in the hydraulic fluid. Accumulators can be used to absorb the expanding fluid and / or supply the contracting fluid. When used to dampen pressure pulses, accumulators also absorb and dissipate energy, thereby reducing noise and vibration.

[0011] The accumulator is preloaded so that there will be a minimum pressure for any available fluid. The three types of preload are counterweight, spring, and gas. Of the three types of accumulators, only counterweight accumulators have a constant pressure. The pressure is generated by the weight divided by the area supporting the piston. Counterweight accumulators are attractive from a circuit design point of view, but are not generally practical for mobile applications. They must be mounted vertically, they are relatively large, and they are heavy. Spring-loaded accumulators and gas-charged accumulators weigh less, take up less space, and can be mounted horizontally, although it is preferred to mount the accumulator vertically.

[0012] Gas accumulators are sometimes referred to as having gas springs. Within the gas accumulator category, there are six main types: piston, noise reducer, bellows, diaphragm, and bladder.

[0013] Based on a new architecture recently developed for regulation systems, a reconfiguration of these regulation systems is proposed in the present invention to provide a secondary safety function to the elements involved in supplying and regulating the fuel to the APU (such as the pressure accumulator or the dumper). Summary of the invention

[0014] The invention provides a regulating system according to claim 1 and an aircraft according to claim 15. Preferred embodiments of the invention are defined in the dependent claims.

[0015] In a first inventive aspect, the present invention provides a regulation system for an aircraft, the regulation system comprising a power unit, a fuel pipeline and a heat recovery circuit,

[0016] The power unit includes:

[0017] - a fuel inlet configured to supply liquid fuel to the fuel pipeline,

[0018] - an engine connected to a fuel line, and

[0019] - a power unit outlet configured to discharge gases out of the engine;

[0020] The heat recovery circuit consists of:

[0021] - a working fluid, and

[0022] a heat exchanger connected to the power unit outlet and configured to transfer heat from the exhaust gas of the engine to the working fluid,

[0023] Wherein, the heat recovery circuit also includes a pressure accumulator, which is connected to a section of the fuel pipeline upstream of at least the fuel evaporation and heating section in the power unit through a discharge pipe, and the discharge pipe is configured to discharge the working fluid from the pressure accumulator and includes a valve, which is configured to control the working fluid input to the section of the fuel pipeline.

[0024] The regulation system of the present invention includes a power unit. In some embodiments, the power unit is an auxiliary power unit, also known as an APU, or any propulsion system configured to deliver power to an aircraft or any fuel cell system. In a specific embodiment where the power unit is an APU, the auxiliary power unit is configured to provide standard APU functions, which are used to deliver electrical and pneumatic power for ground operations and flight operations. In addition, the regulation system is suitable for installation in an aircraft.

[0025] The regulation system further comprises a fuel pipeline distributed throughout the regulation system including the power unit and configured to supply the power unit. The power unit comprises a fuel inlet through which liquid fuel is supplied to the fuel pipeline, in particular to a section of the fuel pipeline included in the power unit. Additionally, the power unit comprises an engine connected at an end of the fuel pipeline opposite to the fuel inlet, and a power unit outlet corresponding to the outlet of exhaust gas from the engine.

[0026] The fuel provided to the fuel inlet in the power unit is in liquid phase and is previously stored under specific temperature and pressure conditions. In a preferred embodiment, the fuel is stored at a temperature in the range of 20 K to 30 K. At the fuel inlet, the fuel is injected at a temperature included in the temperature range.

[0027] The regulation system also includes a heat recovery loop, which includes a heat exchanger responsible for recovering heat from the exhaust gas of the power unit. The heat recovery loop also includes a working fluid, which is understood to be a fluid that recirculates within the heat recovery loop. Furthermore, the heat recovery loop is considered to be an independent and closed loop in which the fuel and the working fluid never come into direct contact or mix.

[0028] The working fluid of the heat recovery circuit is constantly recirculated and moved when the power unit of the regulation system is in an operating state (i.e., when running) or when the power unit of the regulation system is not running, so as to avoid freezing of the working fluid when it comes into contact with the fuel pipeline, in which the fuel is at a much lower temperature than the temperature of the working fluid at this specific position which is the first contact point of the working fluid with the fuel pipeline of the power unit, which is located near the fuel inlet of the evaporation device.

[0029] Advantageously, the heat recovery circuit is a thermal support for the power unit, more particularly for the fuel line.

[0030] Furthermore, the heat recovery circuit also comprises a pressure accumulator connected to the heat recovery circuit and the fuel line.

[0031] With regard to the connection of the pressure accumulator to the heat recovery circuit, advantageously, the pressure accumulator absorbs and supplies the volume change of the working fluid in the heat recovery circuit, suppresses the transient pressure in the working fluid, and provides the working fluid to the evaporation and heating sections to compensate for leakage. These are the main functions of the pressure accumulator in the heat recovery circuit.

[0032] In addition, the pressure accumulator is connected to a fuel pipeline, in particular to a section of the fuel pipeline upstream of a fuel evaporation and heating section included in the power unit. In the context of the present invention, the term "upstream" should be understood to refer to a position closest to the fuel inlet of the power unit or the fuel inlet of the regulating system or a position towards the fuel inlet of the power unit or the fuel inlet of the regulating system. On the other hand, the term "downstream" should be understood to refer to a position closest to the power unit outlet or a position towards the position closest to the power unit outlet. The terms "upstream" and "downstream" are both used with respect to the direction of fuel flow.

[0033] This connection between the pressure accumulator and the section of the fuel pipeline is provided by a discharge pipeline responsible for discharging the working fluid from the pressure accumulator towards the fuel of the fuel pipeline. The discharge pipeline comprises a valve for controlling the amount of working fluid entering the section of the fuel pipeline. Providing working fluid from the pressure accumulator to the section of the fuel pipeline advantageously allows cleaning and ventilation of the interior of the fuel pipeline.

[0034] Furthermore, providing a valve in the discharge line advantageously allows the necessary intake of working fluid in order to be able to stop the engine in the power unit.

[0035] Having a pressure accumulator connected to the heat recovery circuit and the fuel line in the regulation system allows performing the above mentioned additional function. Therefore, the main benefit of this additional function of the pressure accumulator is the weight saving at the aircraft level due to the removal of other systems and components responsible for performing this additional function.

[0036] In a particular embodiment, the pressure accumulator is also connected to a section of the fuel pipeline upstream of at least the fuel evaporation and heating section in the power unit via a pressure connection, the pressure connection being configured to transfer pressure and / or fluid between the section of the fuel pipeline and the pressure accumulator.

[0037] The further connection between the pressure accumulator and the section of the fuel line is provided by a pressure connection capable of transmitting the pressure on the section of the fuel line to the pressure accumulator. Advantageously, the pressure connection allows a pressure increase between the fuel line and the interior of the pressure accumulator to be maintained.

[0038] Furthermore, the pressure connection can also transfer fluid from the interior of the pressure accumulator to a section of the fuel line.

[0039] This additional connection between the pressure accumulator and the section of the fuel line provided by the pressure connection replaces a conventional system and its components which perform the above-mentioned functions with regard to transmitting pressure and / or fluid and thus also saves weight.

[0040] In a particular embodiment, both the discharge pipe and the pressure connection are connected to a section of the fuel pipe upstream of the fuel inlet of the power unit. In this embodiment, the section of the field pipe connected to the pressure accumulator is placed outside the power unit, i.e. before the fluid inlet of the power inlet, according to the direction of fuel flow through the fuel pipe. Advantageously, it is ensured that the entire section of the fuel pipe arranged inside the power unit remains free of H2.

[0041] In a particular embodiment, the pressure accumulator is one of the following types: bellows, bladder, and diaphragm.

[0042] Preferably, the pressure accumulator is a bellows-type accumulator comprising:

[0043] -case;

[0044] - a bellows and a spring, the bellows and the spring being arranged inside the housing;

[0045] - a first inlet configured to supply the housing with a working fluid coming from a heat recovery circuit; and - a second inlet configured to supply the fluid to the bellows.

[0046] A bellows type accumulator includes a housing that contains an expandable metal chamber pre-filled with a specific fluid inside, so that the housing is exposed to the high-pressure hydraulic fluid. The walls of the expandable chamber do not contact the walls of the housing, so there is no frictional wear when the bellows expands and contracts. They do not use elastic bladders, diaphragms, or piston seals; therefore, they are not limited by elastomers. Metal bellows operate reliably in high temperatures, extreme wear and harsh environments. Welded bellows are hermetically sealed and can operate reliably without repair or maintenance.

[0047] Furthermore, the bellows-type accumulator comprises a first inlet for incoming working fluid from the heat recovery circuit and a second inlet for incoming fluid to the interior of the bellows or expandable chamber, preferably an expandable metal chamber. Specifically, through this second inlet, the interior of the expandable chamber of the pressure accumulator is filled.

[0048] The pressure accumulator further comprises a spring which is configured to thereby advantageously ensure that the pressure of the heat recovery circuit is always greater than the fuel pressure.

[0049] In a particular embodiment, the bellows-type accumulator further comprises a third inlet configured to connect the pressure connection with the interior of the bellows.

[0050] In a particular embodiment, the pressure connection connects the pressure of the section of the fuel line with the fluid pressure of the bellows of the pressure accumulator via the third inlet, and wherein the pressure transfer between the section of the fuel line and the interior of the bellows is performed by a fluid device with a diaphragm or by a mechanical device such as a piston rod or a rubber material. In this embodiment, the pressure connection allows the pressure of the fuel line to be transferred to the pressure in the accumulator, maintaining the pressure increment between the fuel line and the fluid housing in the bellows of the pressure accumulator. In addition, the fluid device with a diaphragm advantageously avoids fuel leakage to the pressure accumulator.

[0051] In a particular embodiment, the pressure connection is a pressure conduit connecting the interior of the bellows with the section of the fuel pipeline via the third inlet, and wherein the pressure conduit comprises a valve configured to control the pressure and / or the passage of fluid between the section of the fuel pipeline and the interior of the bellows. Specifically, the valve of the pressure conduit allows the transfer of pressure from the section of the fuel pipeline to the interior of the bellows and allows the discharge of the bellows fluid into the section of the fuel pipeline and vice versa. More specifically, the valve transfers pressure when closed and transfers fluid when open.

[0052] In a more particular embodiment, the fluid supplied to the bellows through the third inlet is the same as the fuel flowing through the section of the fuel conduit.

[0053] In another particular embodiment, the fluid supplied to the pressure accumulator through the first inlet is the same as the working fluid of the heat recovery circuit. In other words, the incoming fluid to the interior of the pressure accumulator is the same as the working fluid flowing through the heat recovery circuit.

[0054] In another embodiment, the fluid supplied to the bellows through the second inlet is the same as the working fluid of the heat recovery circuit.Such fluid supply is performed for initial filling of the bellows and maintenance of the pressure accumulator.

[0055] In a particular embodiment, the section of the fuel pipeline includes a main channel surrounded by a double wall volume, and wherein the fuel flows through the main channel in the operating mode. The main channel through which the fuel flows is surrounded by a double wall volume. This arrangement of the double wall volume is for safety, in order to ventilate possible fuel leaks in the main channel.

[0056] More specifically, the discharge conduit is connected to the main channel and / or the double-walled volume. In this sense, the discharge conduit is able to provide the working fluid to both the main channel and the double-walled volume. Since the working fluid is inert, it can be used to ventilate both conduits if necessary.

[0057] In a particular embodiment, the pressure connection is connected to the main channel and / or the double-walled volume.

[0058] In a particular embodiment, the discharge conduit comprises an outlet port connecting the pressure accumulator with the interior of a compartment in which the power unit is located, and wherein the outlet port comprises a valve configured to control the input of working fluid to the interior of the power unit compartment.

[0059] Advantageously, in emergency situations, such as a fire or a fuel leak in the compartment, this outlet port in the discharge duct provides working fluid to the fuselage compartment where the power unit is placed, as well as to the entire regulating system.

[0060] In a particular embodiment, the fluid of the fuel pipeline is hydrogen (H2) and / or the working fluid of the heat recovery loop is nitrogen (N2), helium (He) or a mixture of nitrogen (N2) and helium (He) and / or ethylene glycol water (EGW).

[0061] In some embodiments, the fluid of the fluid conduit is pure hydrogen.

[0062] In some other embodiments, the fluid of the fluid conduit is a mixture of hydrogen and a fuel such as methane, propane, butane. In the specific case where the fluid of the fluid conduit is a mixture, hydrogen is the majority of the mixture.

[0063] In a second inventive aspect, the present invention provides an aircraft comprising a regulating system according to the first inventive aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] These and other features and advantages of the present invention will be clearly understood in view of the detailed description of the present invention which will become apparent from the preferred embodiments of the present invention, which are given by way of example only and not limited thereto, with reference to the accompanying drawings.

[0065] Figure 1 The figure shows a schematic representation of a regulating system according to an embodiment of the invention.

[0066] Figure 2 The figure shows a schematic diagram of an embodiment of the regulating system according to the invention.

[0067] Figure 3 The FIGURE shows a schematic diagram of a further embodiment of the regulating system according to the invention.

[0068] Figure 4 The FIGURE shows a schematic diagram of a further embodiment of the regulating system according to the invention.

[0069] Figure 5 The figure shows a schematic diagram of an aircraft according to the invention. DETAILED DESCRIPTION

[0070] Figure 1 A method for using an aircraft (200) according to an embodiment of the present invention is shown. Figure 5 A schematic representation of a regulation system (100) is shown in FIG.

[0071] exist Figure 1In some embodiments, the regulation system (100) comprises a power unit (1), the power unit (1) comprising a fuel inlet (2), a fuel pipeline (3), an engine (4), a power unit outlet (5), an evaporation device (6) and a heating device (7). In some embodiments, the power unit (1) is an auxiliary power unit or APU. In some other embodiments, the power unit (1) is a propeller.

[0072] In some embodiments, the fuel is hydrogen. In a preferred embodiment, the hydrogen is stored at 20 K before being injected into the power unit (1), and the conditioning system (100) of the present invention provides heat to the hydrogen so that the temperature of the hydrogen before entering the engine (4) is constant at 288 K. Also in a preferred embodiment, the fuel, preferably hydrogen, is injected into the conditioning system (100) at 1.25 MPa.

[0073] The fuel inlet (2) is configured to supply liquid fuel to the fuel pipeline (3), and the portion of the fuel pipeline (3) placed in the power unit (1) connects the fuel inlet (2) to the engine (4). The engine (4) comprises an inlet (4.1) and an outlet (4.2) connected to the power unit outlet (5). The power unit outlet (5) is configured to exhaust gas from the engine (4). In a specific embodiment, the engine (4) is a gas turbine.

[0074] Then, in Figure 1 In an embodiment, the evaporation device (6) is connected to the fuel inlet (2) via the fuel pipeline (3) and comprises a fuel inlet (6.1) and a fuel outlet (6.2). The evaporation device (6) is configured to supply heat to the fuel in the fuel pipeline (3) and to change the fuel in the fuel pipeline (3) from a liquid form to a gaseous form. In some embodiments, the fuel injected into the evaporation device (6) is completely changed into a gaseous form at the fuel outlet (6.2) of the evaporation device (6).

[0075] Also in Figure 1In the embodiment of the present invention, the power unit (1) of the regulating system (100) further comprises a heating device (7) located downstream of the evaporation device (6). The heating device (7) comprises a fuel inlet (7.1) connected to the fuel outlet (6.2) of the evaporation device (6) by the fuel pipe (3), and the heating device (7) further comprises a fuel outlet (7.2). The heating device (7) is configured to supply heat to the fuel of the fuel pipe (3). In particular, the heating device (7) provides additional heat to the fuel pipe (3). The heating device (7) is considered to be a support for the regulating system (100), so that when the engine is not yet running, the heat of the fuel supplied to the fuel pipe (3) comes from the heating device (7), and later when the regulating system (100) is in full working mode, the heat of the fuel transferred from the working fluid of the heat recovery circuit (8) to the fuel pipe (3) covers the total heat required to heat the fuel of the fuel pipe (3), so that the heat provided by the heating device (7) is reduced until the heating device (7) can be stopped.

[0076] In some other embodiments, the heating device (7) is located upstream of the evaporation device (6).

[0077] In some embodiments, the heating device (7) is provided with a dedicated battery, so that the function of the heating device (7) is independent of the remaining elements of the regulation system (100).

[0078] Also in some embodiments, the evaporation device (6) and the heating device (7) are encapsulated in order to avoid leakage outside the encapsulation of the evaporation device (6) and / or the heating device (7), which would damage the rest of the conditioning system (100).

[0079] Back to Figure 1 In an embodiment of the present invention, a fuel pipe (3) connects a fuel outlet (7.2) of the heating device (7) to an inlet (4.1) of the engine (4).

[0080] In some embodiments, the fuel conduit (3) between the heating device (7) and the engine (4) is a flexible hose.

[0081] Figure 1 The depicted regulation system (100) further comprises a heat recovery circuit (8). The heat recovery circuit (8) comprises a heat exchanger (9) in fluid communication with the evaporation device (6) and a working fluid. The working fluid flows along the entire heat recovery circuit (8) at a working fluid pressure reference value PWF.

[0082] The heat recovery circuit (8) is also configured to supply working fluid heat from the exhaust gas of the power unit (1) to the fuel of the fuel pipe (3) by means of the evaporation device (6). That is, the fuel pipe (3) of the evaporation device (6) and the heat recovery circuit (8) share a common surface in order to transfer said heat recirculated from the heat recovery circuit (8). Advantageously, the heat exchanger (9) covers the entire vertical cross-section of the power unit outlet in order to utilize the maximum heat from the exhaust gas generated by the functioning of the power unit (1).

[0083] The heat exchanger (9) is connected to the power unit outlet (5) and comprises an inlet (9.1) and an outlet (9.2). The heat exchanger (9) is configured to transfer heat from the exhaust gas of the power unit outlet (5) to the working fluid located inside the heat recovery circuit (8). The heat exchanger (9) is also configured to supply the working fluid from the heat exchanger (9) to the evaporation device (6), and the evaporation device (6) is configured to supply the working fluid heat from the working fluid of the heat recovery circuit (8) to the fuel of the fuel pipeline (3). According to an embodiment, the length of the heat exchanger (9) ensures that the pressure drop is minimized. More particularly, the heat exchanger (9) is a pillow plate heat exchanger or PPHE.

[0084] Preferably, the heat exchanger (9) is configured to cover the entire area of ​​the power unit outlet (5) so that maximum heat is generated and transferred from the exhaust gas of the engine (4) to the working fluid of the heat recovery circuit (8).

[0085] The heat exchanger (9) is activated as soon as the power unit (1) is in operation in order to extract heat from the exhaust gas at the power unit outlet (5) at the earliest possible time, or before the engine (4) is in operation, so that the heat recovery circuit (8) supplies heat to the fuel in the fuel line (3) as quickly as possible by means of the working fluid and the evaporation device (6), so that the heating device (7) is switched off in the shortest possible time as soon as the evaporation device (6) is able to supply heat to the fuel in the fuel line (3) required for the engine (4) of the power unit (1) to reach the operating state independently without support from the heating device (7), that is, when the fuel reaches a temperature between 225K and 330K.

[0086] Also preferably, the working fluid of the heat recovery loop (8) is nitrogen (N2) or helium (He), or a mixture of nitrogen (N2) and helium (He), and / or ethylene glycol water (EGW).

[0087] Also in Figure 1In the embodiment depicted, the heat recovery circuit (8) includes a first pumping device (12) located downstream of the evaporation device (6), which actuates the circulation flow of the working fluid in the heat recovery circuit (8). The function and control of the first pumping device (12) are independent of the engine (4). In the same embodiment, the heat recovery circuit (8) shows a pressure accumulator (13) located downstream of the first pumping device (12) and configured to regulate the pressure of the working fluid in the heat recovery circuit (8). In addition, the first pumping device (12) helps to provide the minimum pressure increment required for the working fluid to flow in the heat recovery circuit (8).

[0088] In some embodiments, the pressure of the working fluid is higher than the pressure of the fluid in the fluid conduit (3).

[0089] Also in Figure 1 In the embodiment shown, the heat recovery circuit (8) comprises a first bypass conduit (14) configured to connect a first portion of the heat recovery circuit and a second portion of the heat recovery circuit. The first portion is located upstream of the inlet (9.1) of the heat exchanger (9), and the second portion of the second conduit is located downstream of the outlet (9.2) of the heat exchanger (9).

[0090] In a preferred embodiment, the heat exchanger (9) is of the pillow plate heat exchanger type. Pillow plate heat exchangers provide high performance with a more compact structure and lighter weight than conventional heat exchangers while providing good structural stability.

[0091] In some other embodiments, the heat recovery circuit (8) comprises a second bypass conduit, which is configured to connect a third portion of the heat recovery circuit (8) and a fourth portion of the heat recovery circuit (8). The third portion is located between the evaporation device (6) and the first portion of the heat recovery circuit (8), and the fourth portion of the heat recovery circuit (8) is located between the second portion of the heat recovery circuit (8) and the evaporation device (6).

[0092] exist Figure 1 In an embodiment of the present invention, the regulating system (100) further comprises a second pumping device (10) and a valve (11), which are configured to supply fuel to the power unit (1). In particular, the second pumping device (10) helps to maintain the pressure of the fuel injected into the power unit (1) at the inlet (2). In addition, the valve (11) allows the regulating system (100) to be opened and closed in the case of performing maintenance or in any case where it is necessary to shut off the fuel entering the power unit (1).

[0093] Also in Figure 1In the depicted embodiment, the second pumping device (10) and the valve (11) are encapsulated, which avoids any leakage of fuel outside the encapsulation area when both the second pumping device (10) and the valve (11) are considered to be critical elements with a high risk of leakage.

[0094] In some embodiments, the fuel pipeline (3) and the heat recovery circuit (8) of the evaporation device (6) are installed in countercurrent. By installing the fuel pipeline (3) and the heat recovery circuit (8) in countercurrent, the regulation system (100) improves the heat exchange between the fuel of the fuel pipeline (2) and the working fluid of the heat recovery circuit (8), so that when in contact with the fuel outlet (6.2) of the evaporation device (6), the temperature of the working fluid is higher, and in the part of the heat recovery circuit (8) in contact with the fuel inlet (6.1) of the evaporation device (6), the temperature of the working fluid is lower. Advantageously, in the case of countercurrent, the temperature increment between the temperature of the working fluid inside the evaporation device (6) and the temperature of the fuel at two corresponding points is positive, which ensures optimal heat transfer from the working fluid to the fuel.

[0095] according to Figure 1 And in particular according to the invention, the pressure accumulator (13) is connected to a section (3.1) of the fuel pipeline (3) located upstream of the fuel inlet (2) of the power unit (1). That is, the fuel pipeline (3) is arranged along the regulating system (100) so that a part of the fuel pipeline (3) is placed inside the power unit (1) and the rest of the fuel pipeline (3) is placed outside the power unit (1) or upstream of the fuel inlet (2) of the power unit (1). The pressure accumulator (13) is connected to the section (3.1) of the fuel pipeline (3) for fluid exchange between the pressure accumulator (13) and the section (3.1) of the fuel pipeline (3) through the valve (V) in a regular manner as shown. The pressure accumulator (13) is connected to the fuel pipeline section (3.1) as described below with reference to Figures 2 to 4 as described.

[0096] Figures 2 to 4 A pressure accumulator (13) is shown as a bellows-type accumulator. The pressure accumulator (13) comprises a housing (13.1) housing a bellows (13.2) and a spring (13.3) inside. The pressure accumulator (13) further comprises a first inlet (13.4) connecting the housing (13.1) to a heat recovery circuit (8), thereby allowing the housing to be supplied with working fluid from the heat recovery circuit (8). Furthermore, the pressure accumulator (13) further comprises a second inlet (13.5) suitable for supplying fluid to the interior of the bellows (13.2) for initial filling and maintenance of the pressure accumulator (13). Specifically, in Figure 2Through the second inlet (13.5), the interior of the bellows (13.2) is filled with the same working fluid as the heat recovery circuit (8).

[0097] In addition, these Figures 2 to 4 The section (3.1) of the fuel pipe (3) shown in FIG. 1 is formed by a main channel (3.1.1) and a double-walled volume (3.1.2) surrounding the main channel (3.1.1). The fuel flows through the main channel (3.1.1.) in the operating mode, and the direction of the fuel flow is indicated by the fuel arrow (F). According to these Figures 2 to 4 In an embodiment, the fuel is hydrogen.

[0098] Figure 2 An embodiment of a pressure accumulator (13) connected to a section (3.1) of a fuel pipeline (3) upstream of a fuel inlet of a power unit (not shown in this figure) is shown. Figure 2 In an embodiment, the pressure accumulator (13) is connected to the section (3.1) of the fuel pipeline (3) via a discharge pipe (15), and the discharge pipe (15) is used to discharge the working fluid from the inside of the housing (13.1) of the pressure accumulator (13) and from the heat recovery circuit (8) to the inside of the section (3.1) of the fuel pipeline (3). That is, the working fluid that has been supplied to the inside of the housing (13.1) and from the heat recovery circuit (8) through the first inlet (13.4) is the fluid discharged from the pressure accumulator (13) through the discharge pipe (15). Specifically, the discharge pipe (15) includes a valve (15.1) that regulates the working fluid input to the inside of the section (3.1). In addition, the pressure accumulator (13) includes an outlet (13.7) that connects the inside of the housing (13.1) with the discharge pipe (15).

[0099] The discharge pipe (15) is connected to the main channel (3.1.1) and the double-walled volume (3.1.2). The discharged working fluid is represented by a first arrow (F1) with a connecting line, as shown in FIG. Figure 2 The discharge of the working fluid from the pressure accumulator (13) to the section (3.1) of the fuel line (3) allows the ventilation and cleaning of the interior of the section (3.1): both the main channel (3.1.1) and the double-walled volume (3.1.2). Furthermore, the discharge of the working fluid through the fuel line (3) allows the stopping of the engine (4) of the power unit (1) (at Figure 1 not shown).

[0100] Figure 3 and Figure 4 Embodiments of a pressure accumulator (13) connected to a section (3.1) of a fuel pipeline (3) upstream of a fuel inlet of a power unit (not shown in this figure) are shown. According to these embodiments, the pressure accumulator (13) is connected to a section (3.1) of a fuel pipeline (3) upstream of a fuel inlet of a power unit (not shown in this figure). Figure 2 The discharge line (15) has already been described and is also connected to the section (3.1) of the fuel line (3) via a pressure connection (16) for transmitting pressure and / or fluid between the section (3.1) of the fuel line (3) and the pressure accumulator (13). Figure 3 and Figure 4 Both show that the pressure accumulator (13) comprises a third inlet (13.6) connecting the pressure connection (16) with the interior of the bellows (13.2).

[0101] exist Figure 3 In the embodiment shown, the pressure connection (16) is a pressure pipe (16.1) which connects the interior of the bellows (13.2) of the accumulator (13) to the interior of the main channel (3.1.1) and / or to the double-walled volume (3.1.2) via a third inlet (13.6). This pressure connection provided by the pressure pipe (16.1) allows the pressure to be transferred from the section (3.1) of the fuel line (3) to the interior of the bellows (13.2) and / or the bellows (13.2) fluid to be discharged into the section (3.1) of the fuel line (3) and vice versa. In particular, the pressure pipe (16.1) comprises a valve (16.1.1) which controls the passage of fluid between the main channel (3.1.1) and / or the double-walled volume (3.1.2) and the interior of the bellows (13.2) of the pressure accumulator (13). The fluid discharged from the bellows (13.2) is indicated by the second arrow (F2), as shown in FIG. Figure 3 As shown. In addition, the valve (16.1.1) can control the passage of pressure between the main channel (3.1.1) and the inside of the bellows (13.2). In a more specific embodiment, the valve (16.1.1) allows pressure to pass when closed, and allows fluid to pass when open. Figure 3 In FIG. 1 , the valve (16.1.1) is considered to be open because the fluid from the bellows (13.2) flows through the main channel (3.1.1) and the double-walled volume (3.1.2).

[0102] In addition, according to Figure 3 In the embodiment shown, the fluid supplied to the interior of the bellows (13.2) through the third inlet (13.6) connected to the pressure connection (16) is hydrogen (the same fluid as flows through the main channel (3.1.1) of the section (3.1) of the fuel pipe (3)).

[0103] exist Figure 4In the embodiment shown, the pressure connection (16) allows the pressure to be transferred from the main channel (3.1.1) of the fuel section (3.1) through the third inlet (13.6) to the inside of the bellows (13.2). In an embodiment (not shown), the pressure connection (16) is a fluid device with a diaphragm or a mechanical device such as a piston rod or a rubber material.

[0104] The pressure exchange between the main channel (3.1.1) of the section (3.1) of the fuel line (3) and the bellows (13.2) of the pressure accumulator (13) allows the pressure increase between the section (3.1) of the fuel line (3) and the fluid housing in the bellows (13.2) to be maintained.

[0105] Figure 4 Also shown is a discharge conduit (15) with an outlet port (15.2) connecting the pressure accumulator (13) with the interior of a compartment where the power unit (not shown) is located. The outlet port (15.2) has a valve (15.3) that controls the passage of the working fluid from the pressure accumulator (13) towards the power unit compartment.

[0106] Figures 2 to 4 A pressure measurement (P) is shown which is arranged at a second inlet (13.5) of the pressure accumulator (13) and is configured to monitor the pressure inside the bellows (13.2). Furthermore, another pressure measurement (P) is arranged at the heat recovery circuit (8) near the first inlet (13.4) of the pressure accumulator (13) which connects the interior of the housing (13.1) with the heat recovery circuit (8). The pressure measurement (P) arranged in the heat recovery circuit (8) monitors the pressure of the working fluid flowing through the heat recovery circuit (8).

[0107] Figure 5 An aircraft (200) is shown comprising a regulation system (not shown) as in any of the embodiments described above.

Claims

1. A regulation system (100) for an aircraft (200), the regulation system (100) comprising a power unit (1), a fuel pipeline (3) and a heat recovery circuit (8), The power unit (1) comprises: - a fuel inlet (2) configured to supply liquid fuel to said fuel conduit (3), - an engine (4) connected to said fuel line (3), and - a power unit outlet (5) configured to discharge gases out of the engine (4); The heat recovery circuit (8) comprises: - a working fluid, and a heat exchanger (9) connected to the power unit outlet (5) and configured to transfer heat from the exhaust gas of the engine (4) to the working fluid, The heat recovery circuit (8) further comprises a pressure accumulator (13), which is connected to a section (3.1) of the fuel pipeline (3) at least upstream of the fuel evaporation (6) and heating (7) sections in the power unit (1) via a discharge pipe (15), wherein the discharge pipe (15) is configured to discharge working fluid from the pressure accumulator (13) and comprises a valve (15.1) configured to control the working fluid input to the section (3.1) of the fuel pipeline (3).

2. The regulating system (100) according to claim 1, wherein: The pressure accumulator (13) is further connected to the section (3.1) of the fuel pipeline (3) upstream of at least the fuel evaporation (6) and heating section in the power unit (1) via a pressure connection (16), the pressure connection (16) being configured to transfer pressure and / or fluid between the section (3.1) of the fuel pipeline (3) and the pressure accumulator (13).

3. The adjustment system (100) according to claim 2, wherein: Both the discharge conduit (15) and the pressure connection (16) are connected to the section (3.1) of the fuel conduit (3) upstream of the fuel inlet (2) of the power unit (1).

4. The regulating system (100) according to any one of the preceding claims, wherein: The pressure accumulator (13) is one of the following types: bellows, air bag and diaphragm.

5. The regulating system (100) according to any one of claims 1 to 4, wherein: The pressure accumulator (13) is a bellows type accumulator, and the bellows type accumulator comprises: - housing (13.1); - a bellows (13.2) and a spring (13.3), said bellows and spring being arranged inside said housing (13.1); - a first inlet (13.4) configured to supply the housing (13.1) with working fluid from a heat recovery circuit (8); and - A second inlet (13.5) configured to supply fluid to said bellows (13.2).

6. The regulating system (100) according to any one of claims 2 to 3 and claim 5, wherein: The bellows-type accumulator (13) further comprises a third inlet (13.6) configured to connect the pressure connection (16) with the interior of the bellows (13.2).

7. The regulating system (100) according to claim 6, wherein: The pressure connection (16) connects the pressure of the section (3.1) of the fuel pipeline (3) to the fluid pressure of the bellows (13.2) of the pressure accumulator (13) via the third inlet (13.6), and the pressure transmission between the section (3.1) of the fuel pipeline (3) and the interior of the bellows (13.2) is performed by a fluid device with a diaphragm or by a mechanical device such as a piston rod or a rubber material.

8. The adjustment system (100) according to claim 6, wherein: The pressure connection (16) is a pressure conduit (16.1) connecting the interior of the bellows (13.2) to the section (3.1) of the fuel pipeline (3) via the third inlet (13.6), and wherein the pressure conduit (16.1) comprises a valve (16.1.1) configured to control the pressure and / or the passage of fluid between the section (3.1) of the fuel pipeline (3) and the interior of the bellows (13.2).

9. The regulating system (100) according to any one of claims 6 to 8, wherein: The fluid supplied to the bellows (13.2) through the third inlet (13.6) is the same as the fuel flowing through the section (3.1) of the fuel pipe (3).

10. The regulating system (100) according to any one of the preceding claims, wherein: The section (3.1) of the fuel pipeline (3) comprises a main channel (3.1.1) surrounded by a double-walled volume (3.1.2), and wherein the fuel flows through the main channel (3.1.1) in an operating mode.

11. The regulating system (100) according to claim 10, wherein: The discharge conduit (15) is connected to the main channel (3.1.1) and / or to the double-walled volume (3.1.2).

12. The regulating system (100) according to any one of claims 2 and 3 to 11, wherein: The pressure connection (16) is connected to the main channel (3.1.1) and / or to the double-walled volume (3.1.2).

13. The regulating system (100) according to any one of the preceding claims, wherein: The discharge conduit (15) comprises an outlet port (15.2) which connects the pressure accumulator (13) with the interior of the compartment in which the power unit (1) is located, and wherein the outlet port (15.2) comprises a valve (15.3) which is configured to control the working fluid input to the interior of the compartment of the power unit (1).

14. The regulating system (100) according to any one of the preceding claims, wherein: The fluid of the fuel pipeline (3) is hydrogen (H2) and / or the working fluid of the heat recovery circuit (8) is nitrogen (N2), helium (He) or a mixture of nitrogen (N2) and helium (He), and / or ethylene glycol water (EGW).

15. An aircraft (200) comprising a regulating system (100) according to any one of the preceding claims.

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