Airborne motor cooling system with liquid ammonia as the medium

Abstract

An airborne motor cooling system with liquid ammonia as the medium, including a cooling air supply port, a liquid ammonia high-pressure storage tank, a first stop valve, a temperature regulating valve, an expansion valve, a flowmeter, a shunt, a temperature sensor, a generator controller, a generator, a drive motor controller, a drive motor, a second stop valve, a pump, and a DSC battery; using liquid ammonia with a large latent heat of vaporization as the motor cooling medium during the aircraft takeoff phase, and achieving motor cooling by utilizing the high-speed convection of the aircraft and air after takeoff. At the same time, an ECU electronic control unit is provided to save ammonia consumption while meeting the cooling effect, and provide a second layer of protection during air cooling. Finally, the high-temperature ammonia gas that has fully exchanged heat is introduced into the DSC battery, and the hydrogen gas generated by the thermal decomposition of ammonia participates in the electrochemical reaction and generates electrical energy. It greatly improves the working environment of the aircraft motor, extends the operation time of the maximum power of the motor, and at the same time realizes the chemical energy reuse of the waste ammonia gas, achieving better safety, stability and economy.

Description

Technical Field

[0001] The present invention relates to the field of airborne motor cooling, and particularly to an airborne motor cooling system using liquid ammonia as a medium. Background Art

[0002] Aircraft electrification is considered a major innovation in the integration of aircraft electromechanical systems and power systems, and has become an important direction in the development of aviation technology. The development in the directions of high power density, miniaturization, light weight, and mechatronics has caused a sharp increase in the heat generation inside the motor and a serious shortage of effective heat dissipation space, which not only shortens the lifespan of the insulation materials inside the motor, reduces the operating efficiency of the motor, but even leads to demagnetization of magnetic materials. Therefore, the cooling problem of aircraft motors is of crucial importance. In the past century of the development of aircraft motors, cooling methods such as natural cooling, water cooling, oil circulation cooling, and oil injection cooling have emerged successively. Among them, with the increase in motor power density and heat load, natural cooling has been difficult to meet the requirements; under the same conditions, the boiling point of water is low, and the water cooling effect is average; oil cooling increases the energy loss during the rotation of the motor rotor due to the high viscosity of the oil, and at the same time, the cost is expensive. Therefore, on the one hand, traditional cooling methods increase the weight of the aircraft itself and the cost is not low, and on the other hand, the heat transfer capacity has reached its limit and cannot meet the increasing heat dissipation requirements of aircraft motors.

[0003] Compared with other cooling media, ammonia is rich in content, so the cost is very low. The cost of refrigeration-grade anhydrous ammonia is usually less than 120 grams per yuan, while the cost of R404A is about 9 grams per yuan, and the cost of R-502 is 4 grams per yuan; in addition to the price, the greater advantage of liquid ammonia lies in its latent heat of vaporization. As a typical refrigerant, its latent heat of vaporization can reach 1.4 MJ / kg, which is 3 times and 2.7 times that of liquid hydrogen / liquid methane. At a temperature of 5°F, its latent heat is 314.1 Cal / g, while R-22 is only 38.4 Cal / g at this time. The efficiency of ammonia is significantly higher, so less ammonia can complete the work, which means a reduction in kilowatt-hours and lower operating costs. Therefore, if ammonia can be used as a cooling medium in aircraft motors, the performance of the motors can be greatly improved. Using ammonia as a refrigerant to manufacture motors will become the general trend.

[0004] From a green perspective, the US Environmental Protection Agency (EPA) encourages the use of ammonia as an ideal alternative to other refrigerants. Due to the long-term use of refrigerants such as R22, the ozone layer is suffering serious damage. If ammonia is used and cooled, further damage can be avoided.

[0005] The flight of an aircraft mainly includes four parts, namely: taxiing, climbing, cruising and landing. The greater the power of the motor, the corresponding increase in the volume and weight of the motor. Traditional aircraft motors often increase the volume and weight of the motor to meet the high power during takeoff, which is obviously not in line with lightweight and miniaturization. An aircraft only needs the motor to operate at high power for 1-2 minutes during takeoff. It is obviously uneconomical to select a larger and heavier motor to achieve high power. Summary of the Invention

[0006] The purpose of the present invention is to solve the above problems in the prior art, and provide an airborne motor cooling system with liquid ammonia as the medium. To meet the maximum motor output torque and the most power required during the climbing stage of the aircraft, ammonia is cooled during this 1-2 minute period, and the motor temperature is effectively reduced to extend the maximum power operation time of the motor, making it possible to select a motor with a smaller volume and mass. During the subsequent level flight stage, the high-speed convection between the aircraft and the air during flight is fully utilized to take away the heat inside the motor through air cooling. Liquid ammonia can also provide a second layer of protection during air cooling, making the entire system more reliable and improving the power density and reliability of the drive motor.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] An airborne motor cooling system with liquid ammonia as the medium, characterized in that it includes a cooling air supply port (4), a liquid ammonia high-pressure storage tank (5), a first stop valve (6), a temperature regulating valve (7), an expansion valve (9), a flow meter (10), a diverter (11), a temperature sensor (12), a generator controller (13), a generator (14), a drive motor controller (15), a drive motor (16), a second stop valve (17), a pump (18), and a DSC battery (19);

[0009] The outlet of the liquid ammonia high-pressure storage tank (5) is connected to the inlet of the first stop valve (6), the outlet of the first stop valve (6) is connected to the inlet of the temperature regulating valve (7), the outlet of the temperature regulating valve (7) is connected to the inlet of the expansion valve (9), the outlet of the expansion valve (9) is connected to the inlet of the flow meter (10), the outlet of the flow meter (10) is connected to the inlet of the diverter (11), and the diverter (11) guides the liquid ammonia to the generator controller (13), the generator (14), the drive motor controller (15), and the drive motor (16) respectively;

[0010] The generator controller (13), generator (14), drive motor controller (15), and drive motor (16) are arranged in parallel. The inlets of the generator controller (13), generator (14), drive motor controller (15), and drive motor (16) are connected to the outlet of the shunt (11). The outlets of the generator controller (13), generator (14), drive motor controller (15), and drive motor (16) are connected to the inlet of the second stop valve (17). The outlet of the second stop valve (17) is connected to the inlet of the pump (18). The outlet of the pump (18) is connected to the anode of the DSC battery (19). The cooling air supply port (4) is connected to the cathode of the DSC battery (19).

[0011] The pump (18) guides ammonia gas to flow from the second stop valve (17) into the anode of the DSC battery (19). The ammonia gas is first thermally decomposed into H2 and N2 at the anode. The H2 undergoes an oxidation reaction at the anode, and air flows from the cooling air supply port (4) into the cathode of the DSC battery (19) to undergo a reduction reaction. At the DSC battery (19), the generated H2 participates in the electrochemical reaction to generate electric energy.

[0012] The present invention further includes a dilute H2SO4 solution (20) and a gas outlet channel (3). The unreacted ammonia gas at the anode of the DSC battery (19) is treated by the dilute H2SO4 solution (20) and then discharged through the gas outlet channel (3). The cathode of the DSC battery (19) is directly connected to the gas outlet channel (3), and the gas outlet channel (3) discharges the remaining air at the cathode of the DSC battery (19).

[0013] The present invention further includes another cooling air supply port (4). After the aircraft takes off, the operating conditions of the generator controller (13), generator (14), drive motor controller (15), and drive motor (16) change. At this time, the cooling of the generator controller (13), generator (14), drive motor controller (15), and drive motor (16) mainly relies on the high-speed convection of the aircraft and the air at the other cooling air supply port (4).

[0014] The present invention further includes an ECU electronic control unit (8). The temperature sensor (12) and the temperature regulating valve (7) are connected to the ECU electronic control unit (8). The ECU electronic control unit (8) controls the opening degree of the temperature regulating valve (7) by receiving the signal from the temperature sensor (12).

[0015] The amount of liquid ammonia to be filled in the liquid ammonia high-pressure storage tank (5) is calculated as follows:

[0016] Q1 = P1(11)n1t

[0017] Q2 = P2(12)n2t

[0018]

[0019]

[0020] M = (m1 + m2) × L

[0021] In the formula, Q1 is the heat generation of the generator (14) and the drive motor (16), in KJ; Q2 is the heat generation of the generator controller (13) and the drive motor controller (15), in KJ; P1 is the rated power of the generator (14) and the drive motor (16), in Kw; P2 is the rated power of the generator controller (13) and the drive motor controller (15), in Kw; n1 is the number of generators (14) and drive motors (16); n2 is the number of generator controllers (13) and drive motor controllers (15); η1 is the working efficiency of the generator (14) and the drive motor (16); η2 is the working efficiency of the generator controller (13) and the drive motor controller (15); η3 is the heat exchange efficiency of liquid ammonia; t is the duration of liquid ammonia supply, in s; c p is the specific heat at constant pressure of liquid ammonia, in kJ / (kg); R is the latent heat of vaporization of liquid ammonia, in kJ / kg; T1 is the motor temperature, in °C; T2 is the liquid ammonia temperature, in °C; M is the total mass of liquid ammonia, in kg; m1 is the mass of liquid ammonia required for the generator (14) and the drive motor (16), in kg; m2 is the mass of liquid ammonia required for the generator controller (13) and the drive motor controller (15), in kg; L is the margin coefficient.

[0022] Compared with the prior art, the beneficial effects achieved by the technical solution of the present invention are as follows:

[0023] 1. The aircraft motor cooling system of the present invention using ammonia as the cooling medium cools the aircraft motor by the cooling of ammonia. The latent heat of vaporization of ammonia is 3 to 10 times that of traditional refrigerants, and the efficiency is high.

[0024] 2. During the takeoff of the aircraft, the liquid ammonia in the liquid ammonia high-pressure storage tank is cooled, and the liquid ammonia flow is effectively distributed by the flow divider to cool the generator controller, generator, drive motor controller, and drive motor arranged in parallel on the wing. An expansion valve is provided to make the temperature of the liquid ammonia lower after the pressure is reduced, and the cooling effect is better. In addition, while meeting the cooling effect, the ammonia consumption is saved, thereby reducing the volume of the liquid ammonia high-pressure storage tank.

[0025] 3. After the aircraft takes off, the favorable external heat dissipation conditions are fully utilized to dissipate heat through the high-speed convective wind at the cooling air supply port, simplifying the cooling system. An ECU electronic control unit is provided. If the temperature exceeds the threshold, the liquid ammonia can provide a second layer of protection during air cooling, making the whole system more reliable.

[0026] 4. High-temperature ammonia gas is connected to the anode of the DSC battery and decomposes into H2 and N2 at the anode. The generated H2 participates in the electrochemical reaction to produce electrical energy. The catalyst includes, but is not limited to, Ni-based catalysts such as Ni / BZY, Ni / YSZ catalysts, etc. While the chemical energy of ammonia is fully utilized, the unreacted ammonia is treated with dilute H2SO4 solution. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a schematic structural diagram of the present invention;

[0028] Figure 2 is a schematic internal structure diagram of the DSC battery.

[0029] The markings in the figure are: fuselage 1, wing 2, gas outlet channel 3, cooling air supply port 4, high-pressure liquid ammonia storage tank 5, first stop valve 6, temperature regulating valve 7, ECU electronic control unit 8, expansion valve 9, flow meter 10, diverter 11, temperature sensor 12, generator controller 13, generator 14, drive motor controller 15, drive motor 16, second stop valve 17, pump 18, DSC battery 19, dilute H2SO4 solution 20. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0031] As Figure 1 shown, an aircraft motor cooling system using ammonia as a cooling medium mainly includes a fuselage 1, a wing 2, a gas outlet channel 3, a cooling air supply port 4, a high-pressure liquid ammonia storage tank 5, a first stop valve 6, a temperature regulating valve 7, an ECU electronic control unit 8, an expansion valve 9, a flow meter 10, a diverter 11, a temperature sensor 12, a generator controller 13, a generator 14, a drive motor controller 15, a drive motor 16, a second stop valve 17, a pump 18, a DSC battery 19, and a dilute H2SO4 solution 20.

[0032] The high-pressure liquid ammonia storage tank 5 is stored in the fuselage 1, and the generator controller 13, the generator 14, the drive motor controller 15, and the drive motor 16 are arranged in parallel on the side of the wing 2; the outlet of the high-pressure liquid ammonia storage tank 5 is connected to the inlet of the first stop valve 6, the outlet of the first stop valve 6 is connected to the inlet of the temperature regulating valve 7, the outlet of the temperature regulating valve 7 is connected to the inlet of the expansion valve 9, the outlet of the expansion valve 9 is connected to the inlet of the flow meter 10, the outlet of the flow meter 10 is connected to the inlet of the diverter 11, and the diverter 11 guides the liquid ammonia to the generator controller 13, the generator 14, the drive motor controller 15, and the drive motor 16 respectively.

[0033] The inlets of the generator controller 13, the generator 14, the drive motor controller 15, and the drive motor 16 are connected to the outlet of the diverter 11. The outlets of the generator controller 13, the generator 14, the drive motor controller 15, and the drive motor 16 are connected to the inlet of the second shut-off valve 17. The outlet of the second shut-off valve 17 is connected to the inlet of the pump 18. The outlet of the pump 18 is connected to the anode of the DSC battery 19. The cooling air supply port 4 is connected to the cathode of the DSC battery 19.

[0034] During high-temperature ammonia treatment, the pump 18 guides ammonia to flow from the second shut-off valve 17 into the anode of the DSC battery 19. See Figure 2 , ammonia is first thermally decomposed into H2 and N2 at the anode. H2 undergoes an oxidation reaction at the anode, while air flows into the cathode of the DSC battery 19 from the cooling air supply port 4 to undergo a reduction reaction. At the DSC battery 19, the generated H2 participates in the electrochemical reaction to generate electrical energy.

[0035] For the dilute H2SO4 solution 20 and the gas outlet channel 3, the unreacted ammonia at the anode of the DSC battery 19 is treated by the dilute H2SO4 solution 20 and then discharged through the gas outlet channel 3. The cathode of the DSC battery 19 is directly connected to the gas outlet channel 3, and the gas outlet channel 3 discharges the remaining air at the cathode of the DSC battery 19.

[0036] After the aircraft takes off, the cooling of the generator controller 13, the generator 14, the drive motor controller 15, and the drive motor 16 is achieved by the high-speed convection of the aircraft and the air at another cooling air supply port 4.

[0037] The temperature sensor 12 and the temperature regulating valve 7 are connected to the ECU electronic control unit 8. The ECU electronic control unit 8 controls the opening degree of the temperature regulating valve 7 by receiving the signal from the temperature sensor 12. Specifically, the control parameter can be transmitted from the temperature sensor 12 to the ECU electronic control unit 8. The ECU electronic control unit 8 can be configured to respond to the control parameter to control the opening degree of the temperature regulating valve 7, achieving the throttling of liquid ammonia while cooling the motor. After the aircraft completes the takeoff process, air cooling is used to cool the motor. When the motor temperature exceeds the threshold for a short time, that is, when air cooling is insufficient, the ECU electronic control unit 8 can open the temperature regulating valve 7 again after receiving the alarm signal from the temperature sensor 12, so that the liquid ammonia high-pressure storage tank 5 can replace or support air cooling to cool the motor within a limited time.

[0038] The working principle of the present invention is as follows:

[0039] Before the aircraft takes off, the operation time of the liquid ammonia cooling system is obtained based on the time required for the aircraft to take off and cruise. The normal-temperature high-pressure liquid ammonia in the liquid ammonia high-pressure storage tank 4 is quantitatively determined according to the operation time, and a certain margin is left to support the cooling of short-term overheating in the air-cooling stage. At this time, both the first shut-off valve 6 and the second shut-off valve 17 are in the closed state.

[0040] During the takeoff and climb phase of the aircraft, when it is necessary to cool the aircraft motor, the first shut-off valve 6 is opened, the liquid ammonia flow rate is adjusted by the temperature regulating valve 7, and low-temperature and low-pressure liquid ammonia is obtained through the expansion valve 9. The liquid ammonia flow rate is read through the flowmeter 10. After passing through the first shut-off valve 6, the temperature regulating valve 7, the expansion valve 9, and the flowmeter 10, the liquid ammonia is respectively guided by the diverter 11 to the generator controller 13, the generator 14, the drive motor controller 15, and the drive motor 16 to reduce the temperature. After the heat exchange is completed, the liquid ammonia is converted into high-temperature ammonia gas. When the liquid ammonia has fully completed the heat exchange, the second shut-off valve 17 is opened.

[0041] The generator controller 13, the generator 14, the drive motor controller 15, and the drive motor 16 are arranged in parallel, which can solve the problems caused by different component specifications and pressure losses. A cooling flow channel is formed between the outer peripheral side housing of the generator 14 and the drive motor 16 and the generator 14 and the drive motor 16. The diverter 11 can effectively distribute the cooling ammonia coolant flow rate of the four motors, which not only reduces the development cost but also improves the cooling efficiency of the product. The temperature regulating valve 7 is connected to the ECU electronic control unit 8. The ECU electronic control unit 8 controls the opening degree of the temperature regulating valve 7. When the temperature sensor 12 monitors that the motor temperature is too high, the opening degree of the temperature regulating valve 7 is increased. When the temperature sensor 12 monitors that the motor temperature is too low, the opening degree of the temperature regulating valve 7 is decreased, so as to save the amount of ammonia gas used while ensuring that the system is at a normal temperature.

[0042] After the aircraft takes off and enters the cruise phase, as the altitude increases and the temperature decreases, the operating conditions of the motor change at this time. In this stage, the first shut-off valve 6 and the second shut-off valve 17 are closed, and the high-speed convection of the aircraft with the air during flight is fully utilized to air-cool the motor through the cooling air supply port 4. During the air-cooling stage, when the motor temperature exceeds the threshold value for a short time or the air-cooling is insufficient, the ECU electronic control unit 8 can open the temperature regulating valve 7 again after receiving the alarm signal from the temperature sensor 12. At this time, the first shut-off valve 6 and the second shut-off valve 17 will be opened again, and the liquid ammonia high-pressure storage tank can replace or support the air-cooling to cool the motor within a limited time.

[0043] As Figures 1 - 2 shown, the discharge of high-temperature ammonia gas is connected to the anode of the DSC battery 19 at the outlet of the pump 18. The high-temperature ammonia gas decomposes into H2 and N2 at the anode. The generated H2 undergoes an electrochemical reaction and generates electric energy under the conditions of catalysts such as Ni-based catalysts (such as Ni / BZY, Ni / YSZ, etc.) and high temperature. The cooling air supply port 4 is connected to the cathode of the DSC battery 19. The unreacted ammonia gas at the anode of the DSC battery 19 is treated by the dilute H2SO4 solution 20 and then discharged through the gas outlet channel 3. The cathode of the DSC battery 19 is directly connected to the gas outlet channel 3, and the gas outlet channel 3 discharges the remaining air at the cathode of the DSC battery 19.

[0044] In the takeoff stage of the aircraft, the present invention uses liquid ammonia with a large latent heat of vaporization as the motor cooling medium. After takeoff, the motor is cooled by the high-speed convection of the aircraft and the air. At the same time, an ECU electronic control unit is provided, which can save the ammonia consumption while meeting the cooling effect, and provides a second layer of protection during air cooling. Finally, the high-temperature ammonia gas with sufficient heat exchange is introduced into the DSC battery, and the hydrogen gas generated by the thermal decomposition of ammonia participates in the electrochemical reaction and generates electric energy. This greatly improves the working environment of the aircraft motor, extends the operation time of the maximum power of the motor, and at the same time realizes the chemical energy reuse of the waste ammonia gas, achieving better safety, stability and economy.

Claims

1. An airborne motor cooling system with liquid ammonia as the medium, characterized in that: It includes a cooling air supply port (4), a high-pressure liquid ammonia storage tank (5), a first shut-off valve (6), a temperature regulating valve (7), an ECU electronic control unit (8), an expansion valve (9), a flowmeter (10), a diverter (11), a temperature sensor (12), a generator controller (13), a generator (14), a drive motor controller (15), a drive motor (16), a second shut-off valve (17), a pump (18), and a DSC battery (19); The high-pressure liquid ammonia storage tank (5) is arranged inside the fuselage, and the generator controller (13), the generator (14), the drive motor controller (15), and the drive motor (16) are arranged in parallel on the wing side; The outlet of the high-pressure liquid ammonia storage tank (5) is connected to the inlet of the first shut-off valve (6), the outlet of the first shut-off valve (6) is connected to the inlet of the temperature regulating valve (7), the outlet of the temperature regulating valve (7) is connected to the inlet of the expansion valve (9), the outlet of the expansion valve (9) is connected to the inlet of the flowmeter (10), the outlet of the flowmeter (10) is connected to the inlet of the diverter (11), and the diverter (11) guides the liquid ammonia to the generator controller (13), the generator (14), the drive motor controller (15), and the drive motor (16) respectively; The inlets of the generator controller (13), the generator (14), the drive motor controller (15), and the drive motor (16) are connected to the outlet of the diverter (11), the outlets of the generator controller (13), the generator (14), the drive motor controller (15), and the drive motor (16) are connected to the inlet of the second shut-off valve (17), the outlet of the second shut-off valve (17) is connected to the inlet of the pump (18), the outlet of the pump (18) is connected to the anode of the DSC battery (19), and the cooling air supply port (4) is connected to the cathode of the DSC battery (19); The pump (18) guides ammonia gas to flow into the anode of the DSC battery (19). The ammonia gas first thermally decomposes into H2 and N2 at the anode. H2 undergoes an oxidation reaction at the anode, and air flows into the cathode of the DSC battery (19) from the cooling air supply port (4) to undergo a reduction reaction. At the DSC battery (19), the generated H2 participates in the electrochemical reaction to generate electric energy; It further includes a dilute H2SO4 solution (20) and a gas outlet channel (3). The unreacted ammonia gas at the anode of the DSC battery (19) is treated by the dilute H2SO4 solution (20) and then discharged through the gas outlet channel (3). The cathode of the DSC battery (19) is directly connected to the gas outlet channel (3), and the gas outlet channel (3) discharges the remaining air at the cathode of the DSC battery (19); It further includes another cooling air supply port (4). When the aircraft takes off, the cooling of the generator controller (13), the generator (14), the drive motor controller (15), and the drive motor (16) is achieved by the high-speed convection of the aircraft and the air at the other cooling air supply port (4); The temperature sensor (12) and the temperature regulating valve (7) are connected to the ECU electronic control unit (8). The ECU electronic control unit (8) controls the opening degree of the temperature regulating valve (7) by receiving the signal from the temperature sensor (12). Specifically, the control parameter is transmitted from the temperature sensor (12) to the ECU electronic control unit (8), and the ECU electronic control unit (8) is configured to respond to the control parameter to control the opening degree of the temperature regulating valve (7), achieving the throttling of liquid ammonia while cooling the motor. After the aircraft completes the take-off process, air cooling is used to cool the motor. When the motor temperature exceeds the threshold for a short time, that is, when air cooling is insufficient, the ECU electronic control unit (8) opens the temperature regulating valve (7) again after receiving the alarm signal from the temperature sensor (12), so that the liquid ammonia high-pressure storage tank (5) can replace or support air cooling to cool the motor within a limited time.

2. The airborne motor cooling system using liquid ammonia as a medium according to claim 1, characterized in that: The calculation of the liquid ammonia quantity required in the liquid ammonia high-pressure storage tank (5) is as follows: Q1 = P1(1 - η1)n1t Q2 = P2(1 - η2)n2t M = (m1 + m2)×L Wherein, Q1 is the heat generation of the generator (14) and the drive motor (16), in KJ; Q2 is the heat generation of the generator controller (13) and the drive motor controller (15), in KJ; P1 is the rated power of the generator (14) and the drive motor (16), in Kw; P2 is the rated power of the generator controller (13) and the drive motor controller (15), in Kw; n1 is the number of generators (14) and drive motors (16); n2 is the number of generator controllers (13) and drive motor controllers (15); η1 is the working efficiency of the generator (14) and the drive motor (16); η2 is the working efficiency of the generator controller (13) and the drive motor controller (15); η3 is the heat exchange efficiency of liquid ammonia; t is the liquid ammonia supply duration, s; c p is the specific heat at constant pressure of liquid ammonia, kJ / (kg); R is the latent heat of vaporization of liquid ammonia, kJ / kg; T1 is the motor temperature, °C; T2 is the liquid ammonia temperature, °C; M is the total mass of liquid ammonia, kg; m1 is the mass of liquid ammonia required for the generator (14) and the drive motor (16), kg; m2 is the mass of liquid ammonia required for the generator controller (13) and the drive motor controller (15), kg; L is the margin coefficient.

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