Integrated methanol reforming hydrogen production rotor engine-solid oxide fuel cell hybrid power system for aircraft and control strategy

Abstract

The invention provides an integrated methanol reforming hydrogen production rotor engine-solid oxide fuel cell hybrid power system for an aircraft and a control strategy, the integrated methanol reforming hydrogen production rotor engine-solid oxide fuel cell hybrid power system comprises a rotor engine, a fuel cell, a motor and an ECU, a combustion chamber of the rotor engine is communicated with a methanol supply system and is used for conveying methanol fuel into the combustion chamber of the rotor engine; an inlet of the rotor engine is communicated with the air inlet system; an outlet of the rotor engine is respectively communicated with an inlet of the rotor engine and an anode of the fuel cell through a three-way valve; the fuel cell converts the hydrogen-containing reformed gas into electric energy and is used for providing the electric energy for the motor; the ECU changes the flow of hydrogen-containing reformed gas entering the inlet of the rotor engine and the anode of the fuel cell by changing the opening degree of the three-way valve according to the flight stage characteristics of the aircraft and the temperature of the combustion chamber of the rotor engine. By changing the three-way valve, the power density and takeoff performance of the system are improved, meanwhile, the complexity of the system is reduced, and the hydrogen utilization efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the field of aircraft, and particularly to an integrated methanol reforming hydrogen production rotary engine - fuel cell hybrid power system and control strategy for an aircraft. Background Art

[0002] With the intensification of the global energy crisis and the prominence of environmental problems, the development of efficient and clean energy technologies has become an urgent need. The methanol reforming hydrogen production technology is regarded as an ideal hydrogen source supply solution for fuel cells due to its high hydrogen content and convenience in storage and transportation. At the same time, solid oxide fuel cells have become the preferred power source in fields sensitive to power-to-weight ratio such as aircraft due to advantages such as high energy conversion efficiency and the absence of precious metal catalysts. Therefore, the methanol reforming - fuel cell system shows unique value in solving the bottleneck of hydrogen energy storage and transportation and realizing low-carbon energy transformation. However, the existing fuel cell power systems using methanol reforming technology still have the following technical bottlenecks:

[0003] (1) Insufficient power density: Pure fuel cells are difficult to meet the instantaneous high-power requirements during the takeoff stage of an aircraft, and an additional lithium battery needs to be carried, resulting in an increase in system mass and significantly reducing the payload capacity.

[0004] (2) Low integration degree of reformer: Traditional methanol steam reforming systems rely on independent catalytic reactors and complex thermal management modules, which have a relatively large volume occupation and relatively high catalyst costs, severely restricting the improvement of power-to-weight ratio.

[0005] (3) Poor adaptability to high altitudes: Under high-altitude working conditions, the air density decreases, and the oxygen supply efficiency of the fuel cell cathode decreases, resulting in a decrease in power output.

[0006] Although the existing methanol reforming hydrogen production systems have optimized the hydrogen acquisition path, they require independent catalytic units and external heat sources, increasing system complexity and manufacturing costs. The above defects make it difficult for the existing technology to meet the strict requirements of aircraft for compactness, power-to-weight ratio, and high-altitude stability, and there is an urgent need for an innovative integrated solution. Summary of the Invention

[0007] Aiming at the deficiencies in the existing technology, the present invention provides an integrated methanol reforming hydrogen production rotary engine - fuel cell hybrid power system and control strategy for an aircraft. According to the flight stage characteristics of the aircraft and the temperature of the rotary engine combustion chamber, by changing the three-way valve, the power density and takeoff performance of the system are improved, while the system complexity is reduced and the hydrogen utilization efficiency is increased.

[0008] The present invention achieves the above technical objectives through the following technical means.

[0009] An integrated methanol reforming hydrogen production rotary engine - fuel cell hybrid system for an aircraft, comprising a rotary engine, a fuel cell, an electric motor and an ECU. The output shaft of the rotary engine is used to drive the aircraft; the output shaft of the electric motor is used to drive the aircraft; the combustion chamber of the rotary engine is communicated with a methanol supply system for delivering methanol fuel into the combustion chamber of the rotary engine; the inlet of the rotary engine is connected to an intake system for delivering air into the combustion chamber; the outlet of the rotary engine is respectively communicated with the inlet of the rotary engine and the anode of the fuel cell through a three - way valve; the fuel cell converts the hydrogen - containing reformed gas into electric energy to provide electric energy for the electric motor.

[0010] The ECU changes the opening degree of the three - way valve according to the flight stage characteristics of the aircraft and the temperature of the combustion chamber of the rotary engine, so as to change the flow rate of the hydrogen - containing reformed gas entering the inlet of the rotary engine and the anode of the fuel cell.

[0011] Furthermore, the methanol supply system includes a methanol fuel tank, a fuel pump, a first methanol nozzle and a second methanol nozzle; the methanol fuel tank is sequentially input into the first methanol nozzle and the second methanol nozzle through the fuel pump; the first methanol nozzle is arranged on the cylinder wall of the intake - compression stage of the rotary engine for direct injection into the combustion chamber of the intake - compression stage; by controlling the mass of the fuel injected by the first methanol nozzle, the fuel injected by the first methanol nozzle burns with excess air in the combustion chamber; the second methanol nozzle is arranged on the cylinder wall of the combustion - exhaust stage of the rotary engine for injecting fuel into the combustion chamber with remaining air to generate hydrogen - containing reformed gas at the end of the combustion stroke.

[0012] Furthermore, injection is implemented through the first methanol nozzle in the intake - compression stage, and is mixed with the air naturally aspirated through the intake passage to form a combustible mixture; injection is implemented through the second methanol nozzle at the end of the combustion stroke in the combustion - exhaust stage, and is partially oxidized and reformed with the residual oxygen to generate hydrogen - containing reformed gas; the mass ratio of the fuel injected by the first methanol nozzle to the fuel injected by the second methanol nozzle is in the range of 1:0.3 - 1:0.7.

[0013] Furthermore, a temperature - pressure sensor is arranged on the cylinder block of the rotary engine for measuring the in - cylinder temperature; the ECU changes the opening degree of the three - way valve according to the in - cylinder temperature measured by the temperature - pressure sensor, so as to adjust the recirculation ratio K.

[0014] Furthermore, the effective cross - sectional area of the outlet of the three - way valve communicated with the inlet of the rotary engine is set as A egr , and the effective cross - sectional area of the outlet of the three - way valve communicated with the anode of the fuel cell is set as A fc , and by changing the opening degree of the three - way valve, A egr and A fcSize;

[0015] The calculation of the recirculation ratio K is: K = (A egr / (A egr + A fc )) × 100%.

[0016] Furthermore, based on the recirculation ratio K, the mass injected by the first methanol nozzle, and the mass ratio i of the methanol injected by the first methanol nozzle to that injected by the second methanol nozzle, the relationship between the power distribution ratio and the recirculation ratio K is determined without considering internal energy loss. Specifically:

[0017] The mass of methanol fuel injected by the first methanol nozzle is Q1. The thermal energy generated is determined as W1 based on the mass of methanol fuel Q1 injected by the first methanol nozzle; the mass of methanol fuel injected by the second methanol nozzle is Q1*i, denoted as Q2. The thermal energy generated is determined as W1*i based on the mass of methanol fuel Q2 injected by the second methanol nozzle.

[0018] Without considering internal energy loss, using the law of conservation of energy and the recirculation ratio K, the thermal energy that the reformed gas entering the rotary engine through the three-way valve can generate is K*W1*i. Then, the electrical energy that the reformed gas entering the fuel cell through the three-way valve can generate is (1 - K)*W1*i.

[0019] In the next stroke, the thermal energy generated by the rotary engine is W1 + K*W1*i, and the mechanical energy output by the rotary engine is converted to (W1 + K*W1*i)η, where η is the efficiency.

[0020] Power distribution ratio

[0021] Furthermore, the flight phase characteristics of the aircraft include the flight altitude h and the power demand P. The flight altitude h and the power demand P are acquired by the detector at least.

[0022] When h < 100 m and P > 80% of the rated power, the aircraft is in the takeoff mode; in the takeoff mode of the aircraft, the power distribution ratio α ≥ 80% is controlled.

[0023] When h ≥ 100 m and P ≤ 80% of the rated power, the aircraft is in the cruise mode; in the cruise mode of the aircraft, the power distribution ratio α ≤ 20% is controlled.

[0024] Furthermore, in the cruise mode, when the in-cylinder temperature T measured by the temperature and pressure sensor is < 800 °C, the opening of the three-way valve is changed to make the recirculation ratio K > 60%.

[0025] When 800 °C ≤ the in-cylinder temperature T measured by the temperature and pressure sensor ≤ 1000 °C, the current opening of the three-way valve is maintained to keep the recirculation ratio K at 40% - 60%.

[0026] When the in-cylinder temperature T measured by the temperature and pressure sensor is > 1000 °C, change the opening degree of the three-way valve to make K < 40%.

[0027] A control strategy for the integrated methanol reforming hydrogen production rotary engine - fuel cell hybrid system for the aircraft described above includes the following steps:

[0028] Obtain the flight altitude h and power demand P;

[0029] When h < 100 m and P > 80% of the rated power, the aircraft is in the take-off mode; in the take-off mode of the aircraft, control the power distribution ratio α ≥ 80%;

[0030] When h ≥ 100 m and P ≤ 80% of the rated power, the aircraft is in the cruise mode; in the cruise mode of the aircraft, control the power distribution ratio α ≤ 20%;

[0031] In the cruise mode, when the in-cylinder temperature T measured by the temperature and pressure sensor (11) is < 800 °C, change the opening degree of the three-way valve (10) to make the recirculation ratio K > 60%;

[0032] When 800 °C ≤ the in-cylinder temperature T measured by the temperature and pressure sensor (11) ≤ 1000 °C, maintain the current opening degree of the three-way valve (10) to make the recirculation ratio K remain at 40% - 60%;

[0033] When the in-cylinder temperature T measured by the temperature and pressure sensor (11) is > 1000 °C, change the opening degree of the three-way valve (10) to make K < 40%.

[0034] The beneficial effects of the present invention are as follows:

[0035] 1. For the integrated methanol reforming hydrogen production rotary engine - fuel cell hybrid system for the aircraft described in the present invention, by combining the fuel cell with the methanol reforming hydrogen production rotary engine system, the advantages of both can be fully utilized. The fuel cell uses the hydrogen-rich reformed gas generated by methanol reforming for power generation to achieve efficient and clean energy conversion; while the rotary engine serves as an auxiliary power source to provide additional power support when the fuel cell cannot meet the load demand.

[0036] 2. In the integrated methanol reforming hydrogen production rotor engine - fuel cell hybrid system for aircraft described in the present invention, during the operation of the rotor engine, the reforming fuel can utilize the high temperature and high pressure environment in the cylinder in the later stage of the combustion stroke to carry out partial oxidation reforming of methanol. The high temperature environment in the cylinder can promote the methanol reforming reaction, thereby improving the hydrogen production efficiency and the energy utilization efficiency of the system; the hydrogen-containing reformed gas generated by methanol reforming can not only be supplied to the fuel cell, but also to the rotor engine. The blending of hydrogen can effectively improve the combustion performance of the rotor engine. Further affecting the cylinder temperature at the reforming moment, thereby affecting the methanol reforming process.

[0037] 3. In the integrated methanol reforming hydrogen production rotor engine - fuel cell hybrid system for aircraft described in the present invention, since the reforming is directly carried out in the cylinder, there is no need for an additional reformer, which significantly reduces the volume and mass of the reformer, thereby improving the power density of the entire fuel cell system and making it more suitable for the application of aircraft. And this reforming method uses the high temperature environment in the cylinder in the later stage of the combustion stage to realize partial oxidation reforming of methanol without the need for a catalyst.

[0038] 4. In the integrated methanol reforming hydrogen production rotor engine - fuel cell hybrid system for aircraft described in the present invention, according to the flight stage characteristics of the aircraft and the temperature of the rotor engine combustion chamber, by changing the opening degree of the three-way valve, a reasonable distribution of hydrogen between the rotor engine and the fuel cell is achieved, improving the utilization efficiency of hydrogen. During the takeoff stage, the rotor engine can be used as the main power source to provide instantaneous high power output, effectively solving the problem of insufficient power response of the fuel cell during the takeoff stage. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. The following drawings are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, it is obvious that other drawings can also be obtained according to these drawings.

[0040] Figure 1 It is a schematic diagram of the integrated methanol reforming hydrogen production rotor engine - fuel cell hybrid system for aircraft described in the present invention.

[0041] Figure 2 It is a power output control logic diagram described in the present invention.

[0042] In the figure:

[0043] 1 - Throttle valve; 2 - Intake passage; 3 - ECU; 4 - Methanol fuel tank; 5 - Fuel pump; 6 - First methanol nozzle; 7 - Spark plug; 8 - Second methanol nozzle; 9 - Oxygen sensor; 10 - Three-way valve; 11 - Temperature and pressure sensor; 12 - Cathode; 13 - Anode; 14 - Air flow meter; 15 - Rotary engine; 16 - Exhaust passage; Detailed implementation manners

[0044] Embodiments of the present invention will be described in detail below. Examples of the embodiments are shown in the drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the drawings are exemplary and are intended to explain the present invention and should not be construed as limiting the present invention.

[0045] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "axial", "radial", "vertical", "horizontal", "inner", "outer", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. These are only for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "a plurality" means two or more unless otherwise specifically defined.

[0046] In the present invention, unless otherwise clearly specified and limited, the terms "mounted", "connected", "connected to", "fixed", etc. should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0047] As Figure 1As shown in the figure, for the integrated methanol reforming hydrogen production rotor engine - fuel cell hybrid power system for aircraft of the present invention, two power devices are installed on the aircraft. One is the rotor engine 15, and the other is the electric motor. The output shaft of the rotor engine 15 is used to drive the blades of the aircraft; the output shaft of the electric motor is used to drive the blades of the aircraft; generally, the output shafts of the rotor engine 15 and the electric motor are respectively input into the hybrid drive system, and the output end of the drive system is connected to the blades of the aircraft; the hybrid drive system is the drive system of a common hybrid vehicle and is an existing structure. The combustion chamber of the rotor engine 15 of the present invention is connected to the methanol supply system for delivering methanol fuel into the combustion chamber of the rotor engine 15; the inlet of the rotor engine 15 is connected to the intake system for delivering air into the combustion chamber; the outlet of the rotor engine 15 is connected to the inlet of the rotor engine 15 and the anode 13 of the fuel cell through a three - way valve 10. On the one hand, the hydrogen - containing reformed gas entering the inlet of the rotor engine 15 can effectively improve the flame propagation efficiency in the combustion stage, realizing the improvement of combustion performance, thereby affecting the in - cylinder temperature, pressure and other environmental parameters at the reforming moment; on the other hand, the hydrogen - containing reformed gas entering the anode of the fuel cell is converted into electric energy to provide electric energy for the electric motor; the ECU 3 changes the opening degree of the three - way valve 10 according to the flight - stage characteristics of the aircraft and the temperature of the combustion chamber of the rotor engine 15, thereby changing the flow rate of the hydrogen - containing reformed gas entering the inlet of the rotor engine 15 and the anode 13 of the fuel cell.

[0048] The methanol supply system includes a methanol fuel tank 4, a fuel pump 5, a first methanol nozzle 6 and a second methanol nozzle 8; the methanol fuel tank 4 is sequentially input into the first methanol nozzle 6 and the second methanol nozzle 8 through the fuel pump 5; the first methanol nozzle 6 is arranged on the cylinder wall of the intake - compression stage of the rotor engine 15 for direct injection into the combustion chamber in the intake - compression stage; by controlling the mass of the fuel injected by the first methanol nozzle 6, the fuel injected by the first methanol nozzle 6 burns with excess air in the combustion chamber, that is, the air entering the combustion chamber is more than the amount of fuel injected by the first methanol nozzle 6. After ignition by the spark plug 7, the fuel injected by the first methanol nozzle 6 burns completely, leaving some air; the second methanol nozzle 8 is arranged on the cylinder wall of the combustion - exhaust stage of the rotor engine 15 and injects fuel into the combustion chamber with remaining air at the end of the combustion stroke for a partial oxidation reforming reaction with the remaining part of the air to produce hydrogen - containing reformed gas. That is, at the end of the combustion stroke, the second nozzle injects methanol fuel into the cylinder for a partial oxidation reforming reaction with the remaining air from the combustion reaction to produce intermediate products such as hydrogen and carbon monoxide. Intermediate products such as hydrogen and carbon monoxide can be collectively called reformed gas, and the reformed gas includes hydrogen. Reaction formula: CH3OH + 0.5O2 → 2H2 + CO (ΔH = - 192.2kJ / mol).

[0049] The intake system generally intakes air by natural aspiration. An electronic throttle valve 1 is installed on the intake passage 2, and the opening degree of the throttle valve 1 can be controlled by the ECU 3.

[0050] In the intake-compression stage, injection is implemented through the first methanol nozzle 6 to form a combustible mixture; in the combustion-exhaust stage, hydrogen-rich reformed gas is generated through the second methanol nozzle 8 at the end of the expansion stroke; the mass ratio of the injection of the first methanol nozzle 6 to the second methanol nozzle 8 is within the range of 1:0.3 - 1:0.7.

[0051] A temperature and pressure sensor 11 is provided on the cylinder block of the rotary engine 15 to measure the in-cylinder temperature; the ECU 3 changes the opening degree of the three-way valve 10 according to the in-cylinder temperature measured by the temperature and pressure sensor 11, thereby adjusting the recirculation ratio K. Let the effective cross-sectional area of the outlet of the three-way valve 10 connected to the inlet of the rotary engine 15 be A egr , and the effective cross-sectional area of the outlet of the three-way valve 10 connected to the anode 13 of the fuel cell be A fc , change the opening degree of the three-way valve 10, thereby changing A egr and A fc The calculation of the recirculation ratio K is: K = (A egr / (A egr +A fc ))×100%.

[0052] When K is 0, the effective cross-sectional area of the outlet of the three-way valve 10 connected to the inlet of the rotary engine 15 is 0, that is, the outlet of the rotary engine 15 is blocked from the inlet of the rotary engine 15, and all the reformed gas at the outlet of the rotary engine 15 enters the anode 13 of the fuel cell; when K is 100, the effective cross-sectional area of the outlet of the three-way valve 10 connected to the anode 13 of the fuel cell is 0, that is, the outlet of the rotary engine 15 is blocked from the anode 13 of the fuel cell, and all the reformed gas at the outlet of the rotary engine 15 enters the inlet of the rotary engine 15.

[0053] According to the principle of energy conservation, the methanol injected by the first methanol nozzle 6 completely burns with the excessive oxygen to produce carbon dioxide and water. At this stage, the chemical energy of methanol is mainly converted into heat energy, increasing the surrounding temperature. In the later stage of the combustion phase, the methanol injected by the second methanol nozzle 8 serves as the reforming fuel. Utilizing the high-temperature environment formed by the combustion of the methanol injected by the first methanol nozzle 6, it undergoes partial oxidation reforming with the remaining oxygen to produce a hydrogen-containing reformed gas. At this stage, the chemical energy of the methanol and oxygen ejected by the second methanol nozzle 8 is converted into the chemical energy of the reformed gas, such as products like hydrogen and carbon monoxide. In addition, the partial oxidation reforming reaction of methanol is an exothermic reaction, and part of the chemical energy of methanol is released in the form of heat energy. Eventually, a high-temperature reformed gas is formed in the exhaust stage. Therefore, based on the recirculation ratio K, the mass injected by the first methanol nozzle 6, and the mass ratio i of the injection of the first methanol nozzle 6 to the second methanol nozzle 8, the relationship between the power distribution ratio and the recirculation ratio K is determined without considering internal energy loss. Specifically:

[0054] The mass of the methanol fuel injected by the first methanol nozzle 6 is Q1, and the heat energy generated is determined as W1 based on the mass Q1 of the methanol fuel injected by the first methanol nozzle 6; the mass of the methanol fuel injected by the second methanol nozzle 8 is Q1*i, denoted as Q2, and the heat energy generated is determined as W1*i based on the mass Q2 of the methanol fuel injected by the second methanol nozzle 8;

[0055] Without considering internal energy loss, using energy conservation and the recirculation ratio K, it is obtained that the heat energy that the reformed gas entering the rotary engine 15 through the three-way valve 10 can generate is K*W1*i. Then, the electrical energy that the reformed gas entering the fuel cell through the three-way valve 10 can generate is (1 - K)*W1*i;

[0056] In the next stroke, the heat energy generated by the rotary engine 15 is W1 + K*W1*i, and the mechanical energy output by the rotary engine 15 is converted into W1 + K*W1*iη, where η is the efficiency; then the total work is (1 - K)*W1*i + W1 + K*W1*iη; the power distribution ratio α = the mechanical energy generated by the rotary engine 15 / total work, that is:

[0057] Power distribution ratio

[0058] The flight phase characteristics of the aircraft include the flight altitude h and the power demand P. The flight altitude h and the power demand P are at least obtained through a detector; the power demand P is the power consumed by the current flight of the aircraft, which can be estimated based on the aircraft weight, flight speed, altitude, acceleration time, etc. This is an existing calculation method.

[0059] When h < 100 meters and P > 80% of the rated power, the aircraft is in the takeoff mode; in the takeoff mode of the aircraft, the power distribution ratio α is controlled to be ≥ 80%;

[0060] When h ≥ 100 m and P ≤ 80% of the rated power, the aircraft is in the cruise mode; in the cruise mode of the aircraft, the control power distribution ratio α ≤ 20%.

[0061] In the cruise mode, when the in-cylinder temperature T measured by the temperature and pressure sensor 11 < 800 °C, change the opening of the three-way valve 10 to make the recirculation ratio K > 60%;

[0062] When 800 °C ≤ the in-cylinder temperature T measured by the temperature and pressure sensor 11 ≤ 1000 °C, maintain the current opening of the three-way valve 10 to keep the recirculation ratio K at 40% - 60%;

[0063] When the in-cylinder temperature T measured by the temperature and pressure sensor 11 > 1000 °C, change the opening of the three-way valve 10 to make K < 40%.

[0064] In the take-off stage, the rotary engine can be used as the main power source to provide instantaneous high-power output, effectively solving the problem of insufficient power response of the fuel cell in the take-off stage. In the take-off stage, the rotary engine is used as the main power. At this time, the recirculation ratio of the hydrogen-rich reformate gas is adjusted according to the in-cylinder pressure signal in the combustion stage. The hydrogen-rich reformate gas obtained by methanol reforming is mainly used to improve the combustion performance of the rotary engine and provide high-power output power for the aircraft. In the cruise stage, the fuel cell is used as the main power source, and at this time, the rotary engine is used as a reformer to provide hydrogen-rich reformate gas for the fuel cell.

[0065] As Figure 2 shown, the control strategy of the integrated methanol reforming hydrogen production rotary engine - fuel cell hybrid system for the aircraft described in the present invention includes the following steps:

[0066] Obtain the flight altitude h and the power demand P;

[0067] When h < 100 m and P > 80% of the rated power, the aircraft is in the take-off mode; in the take-off mode of the aircraft, the control power distribution ratio α ≥ 80%; according to the power distribution ratio formula, make the recirculation ratio K increase.

[0068] When h ≥ 100 m and P ≤ 80% of the rated power, the aircraft is in the cruise mode; in the cruise mode of the aircraft, the control power distribution ratio α ≤ 20%; according to the power distribution ratio formula, make the recirculation ratio K decrease.

[0069] In the cruise mode, when the in-cylinder temperature T measured by the temperature and pressure sensor 11 < 800 °C, change the opening of the three-way valve 10 to make the recirculation ratio K > 60%; generally make the recirculation ratio K increase.

[0070] When the in-cylinder temperature T measured by the temperature and pressure sensor 11 satisfies 800°C ≤ T ≤ 1000°C, maintain the current opening degree of the three-way valve 10 to keep the recirculation ratio K at 40% - 60%; generally keep the recirculation ratio K unchanged.

[0071] When the in-cylinder temperature T measured by the temperature and pressure sensor 11 is greater than 1000°C, change the opening degree of the three-way valve 10 to make K < 40%. Generally, make the recirculation ratio K decrease.

[0072] It should be understood that although this specification is described according to each embodiment, not every embodiment only contains an independent technical solution. This narrative way of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0073] The series of detailed descriptions listed above are only specific descriptions of the feasible embodiments of the present invention, and they are not intended to limit the protection scope of the present invention. Any equivalent embodiments or modifications made without departing from the technical spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. An integrated methanol reforming hydrogen production rotor engine - solid oxide fuel cell hybrid power system for an aircraft, characterized in that, It includes a rotary engine (15), a fuel cell, an electric motor, and an ECU (3). The output shaft of the rotary engine (15) is used to drive the aircraft; the output shaft of the electric motor is used to drive the aircraft; the combustion chamber of the rotary engine (15) is communicated with a methanol supply system for delivering methanol fuel into the combustion chamber of the rotary engine (15); the inlet of the rotary engine (15) is communicated with an intake system for delivering air into the combustion chamber; the outlet of the rotary engine (15) is respectively communicated with the inlet of the rotary engine (15) and the anode (13) of the fuel cell through a three-way valve (10); the fuel cell converts the hydrogen-containing reformed gas into electric energy for supplying electric energy to the electric motor. The ECU (3) changes the opening degree of the three-way valve (10) according to the flight stage characteristics of the aircraft and the temperature of the combustion chamber of the rotary engine (15), so as to change the flow rate of the hydrogen-containing reformed gas entering the inlet of the rotary engine (15) and the anode (13) of the fuel cell.

2. The integrated methanol reforming hydrogen production rotor engine - solid oxide fuel cell hybrid power system for aircraft according to claim 1, wherein The methanol supply system includes a methanol fuel tank (4), a fuel pump (5), a first methanol nozzle (6), and a second methanol nozzle (8); the methanol fuel tank (4) is sequentially input into the first methanol nozzle (6) and the second methanol nozzle (8) through the fuel pump (5); the first methanol nozzle (6) is arranged on the cylinder wall of the intake-compression stage of the rotary engine (15) for directly injecting methanol fuel into the combustion chamber in the intake-compression stage; by controlling the mass of the fuel injected by the first methanol nozzle (6), the fuel injected by the first methanol nozzle (6) burns with excess air in the combustion chamber; the second methanol nozzle (8) is arranged on the cylinder wall of the combustion-exhaust stage of the rotary engine (15) for injecting reformed fuel into the combustion chamber with remaining air for generating hydrogen-containing reformed gas at the end of the combustion stroke.

3. The integrated methanol reforming hydrogen production rotor engine - solid oxide fuel cell hybrid power system for aircraft according to claim 2, characterized in that, The injection in the intake-compression stage is implemented through the first methanol nozzle (6) to form a combustible mixture; the hydrogen-containing reformed gas is generated through the second methanol nozzle (8) at the end of the expansion stroke in the combustion-exhaust stage; the mass ratio of the methanol fuel injected by the first methanol nozzle (6) to that injected by the second methanol nozzle (8) is within the range of 1:0.3 - 1:0.

7.

4. The integrated methanol reforming hydrogen production rotor engine - solid oxide fuel cell hybrid power system for aircraft according to claim 1, characterized in that, A temperature and pressure sensor (11) is arranged on the cylinder block of the rotary engine (15) for measuring the in-cylinder temperature; the ECU (3) changes the opening degree of the three-way valve (10) according to the in-cylinder temperature measured by the temperature and pressure sensor (11), so as to adjust the recirculation ratio K.

5. The integrated methanol reforming hydrogen production rotor engine - solid oxide fuel cell hybrid power system for aircraft according to claim 4, characterized in that, The effective cross-sectional area of the outlet of the three-way valve (10) communicating with the inlet of the rotary engine (15) is set as A egr , and the effective cross-sectional area of the outlet of the three-way valve (10) communicating with the anode (13) of the fuel cell is set as A fc , change the opening degree of the three-way valve (10) so as to change A egr and A fc ; The calculation of the recirculation ratio K is: K = (A egr / (A egr +A fc )) × 100%.

6. The integrated methanol reforming hydrogen production rotor engine - solid oxide fuel cell hybrid power system for aircraft according to claim 2, wherein According to the recirculation ratio K, the mass of methanol injected by the first methanol nozzle (6), and the mass ratio i of the methanol injected by the first methanol nozzle (6) to that injected by the second methanol nozzle (8), the relationship between the power distribution ratio and the recirculation ratio K is determined without considering the internal energy loss, specifically as follows: The mass of the methanol fuel injected by the first methanol nozzle (6) is Q1, and the thermal energy generated is determined to be W1 based on the mass Q1 of the methanol fuel injected by the first methanol nozzle (6); the mass of the methanol fuel injected by the second methanol nozzle (8) is Q1*i, denoted as Q2, and the thermal energy generated is determined to be W1*i based on the mass Q2 of the methanol fuel injected by the second methanol nozzle (8). Without considering heat energy loss, using the law of conservation of energy and the recirculation ratio K, the thermal energy that the reformed gas entering the rotary engine (15) through the three-way valve (10) can generate is obtained as K*W1*i. Then, the electrical energy that the reformed gas entering the fuel cell through the three-way valve (10) can generate is (1 - K)*W1*i. In the next stroke, the thermal energy generated by the rotary engine (15) is W1 + K*W1*i, and the mechanical energy output by the rotary engine (15) is converted into (W1 + K*W1*i)η, where η is the efficiency; then the total work is (1 - K)*W1*i + W1 + K*W1*iη; the power distribution ratio α = the mechanical energy generated by the rotary engine (15) / the total work. Power distribution ratio 7. The integrated methanol reforming hydrogen production rotor engine - solid oxide fuel cell hybrid power system for aircraft according to claim 6, characterized in that, The flight stage characteristics of the aircraft include the flight altitude h and the power demand P, and at least the flight altitude h and the power demand P are obtained through the detector. When h < 100 m and P > 80% of the rated power, the aircraft is in the takeoff mode; in the takeoff mode of the aircraft, control the power distribution ratio α ≥ 4:

1. When h ≥ 100 m and P ≤ 80% of the rated power, the aircraft is in the cruise mode; in the cruise mode of the aircraft, control the power distribution ratio α ≤ 1:

4.

8. The integrated methanol reforming hydrogen production rotor engine - solid oxide fuel cell hybrid power system for aircraft according to claim 7, characterized in that In the cruise mode, when the in-cylinder temperature T measured by the temperature and pressure sensor (11) < 800 °C, change the opening degree of the three-way valve (10) to make the recirculation ratio K > 60%. When 800 °C ≤ the in-cylinder temperature T measured by the temperature and pressure sensor (11) ≤ 1000 °C, maintain the current opening degree of the three-way valve (10) to make the recirculation ratio K remain at 40% - 60%. When the in-cylinder temperature T measured by the temperature and pressure sensor (11) > 1000 °C, change the opening degree of the three-way valve (10) to make K < 40%.

9. A control strategy for an integrated methanol reforming hydrogen production rotor engine - solid oxide fuel cell hybrid system for an aircraft according to claim 1, characterized in that, It includes the following steps: Obtain the flight altitude h and the power demand P. When h < 100 m and P > 80% of the rated power, the aircraft is in the takeoff mode; in the takeoff mode of the aircraft, control the power distribution ratio α ≥ 80%. When h ≥ 100 m and P ≤ 80% of the rated power, the aircraft is in the cruise mode; in the cruise mode of the aircraft, control the power distribution ratio α ≤ 20%. In the cruise mode, when the in-cylinder temperature T measured by the temperature and pressure sensor (11) < 800 °C, change the opening degree of the three-way valve (10) to make the recirculation ratio K > 60%. When 800 °C ≤ the in-cylinder temperature T measured by the temperature and pressure sensor (11) ≤ 1000 °C, maintain the current opening degree of the three-way valve (10) to make the recirculation ratio K remain at 40% - 60%. When the in-cylinder temperature T measured by the temperature and pressure sensor (11) > 1000 °C, change the opening degree of the three-way valve (10) to make K < 40%.

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