Control method of three-bed airborne oxygen generation system

Abstract

The invention provides a control method of a three-bed airborne oxygen generation system, which comprises the following steps: when an electromagnetic valve is electrified, pressurizing and adsorbing molecular sieve beds and outputting oxygen-enriched product gas, and meanwhile, carrying out back flushing on the other two molecular sieve beds by a flushing device; when the electromagnetic valve is powered off, the molecular sieve beds are subjected to pressure relief desorption, the three molecular sieve beds alternately and circularly work in this way, the processes of pressurized adsorption, pressure relief desorption and flushing purification are implemented, and oxygen-enriched product gas is continuously output; after the oxygen monitor is powered on, T1-second self-inspection is carried out, and power-on BIT detection is carried out in the self-inspection period; after the T1-second self-inspection is finished, the cycle BIT detection is carried out; through the coupling design of the power-on BIT and the period BIT and the reasonable setting of each fault reporting logic and threshold value, the fault detection rate and the fault isolation rate of the system are improved, the false alarm rate is reduced, and the system is convenient to detect and maintain.

Description

Technical Field

[0001] This invention belongs to the field of molecular sieve oxygen generation technology, and particularly relates to a control method for a three-bed airborne oxygen generation system. Background Technology

[0002] Currently, the BIT design of aircraft airborne oxygen generation systems is not comprehensive, resulting in substandard testability indicators and unreasonable fault reporting logic settings, leading to a high false alarm rate.

[0003] Therefore, it is necessary to improve the design of BIT to enhance the system's fault detection and isolation rates and reduce the false alarm rate. Summary of the Invention

[0004] To address the technical problems of low fault detection and isolation rates and high false alarm rates in existing aircraft airborne oxygen generation systems, this invention provides a control method for a three-bed airborne oxygen generation system. Through a coupled design of power-on bit and periodic bit, and by rationally setting each fault reporting logic and threshold, the system's fault detection and isolation rates are improved, the false alarm rate is reduced, and system testing and maintenance are facilitated. The technical solution is as follows: Firstly, a control method for a three-bed airborne oxygen generation system is provided, the method comprising: After the three-bed onboard oxygen generation system is connected to the power and gas source, the introduced compressed air flows through the inlet filter and gas source treatment device. The inlet pressure sensor measures the pressure after the inlet filter. After water removal and filtration, the gas enters the pressure reducer. The reduced gas then enters the pneumatic valve and the solenoid valve respectively. When the solenoid valve is energized, the inlet valve is opened and the exhaust valve is closed by indirectly controlling the air pressure in the upper chamber of the pneumatic valve membrane. This causes the molecular sieve bed to be pressurized for adsorption, outputting oxygen-enriched product gas. At the same time, the flushing device performs reverse flushing on the other two molecular sieve beds. When the solenoid valve is de-energized, the inlet valve is closed and the exhaust valve is opened by indirectly controlling the air pressure in the upper chamber of the pneumatic valve membrane. This causes the molecular sieve bed to be depressurized for desorption. The three molecular sieve beds work in this interactive cycle, implementing the pressurization adsorption, depressurization desorption, and flushing purification process, continuously outputting oxygen-enriched product gas. After the oxygen monitor is powered on, it enters a T1-second self-test, during which a power-on BIT test is performed; after the T1-second self-test ends, it enters a periodic BIT test.

[0005] Among them, the three-bed on-board oxygen generation system includes an inlet filter, an intake pressure sensor, a gas source treatment device, a pressure reducer, a safety valve, a pneumatic valve, a solenoid valve, a molecular sieve bed, a flushing device, a gas storage tank, a product gas pressure sensor, and an oxygen monitor. Among them, a cabin pressure sensor and an oxygen partial pressure sensor are provided in the oxygen monitor. The pneumatic valve has an intake valve and an exhaust valve. The software of the three-bed on-board oxygen generation system is embedded in the single-chip microcomputer of the oxygen monitor. The software of the three-bed on-board oxygen generation system is configured with a BIT detection module, and the BIT detection module performs power-on BIT detection and periodic BIT detection.

[0006] Optionally, the power-on BIT detection includes communication fault detection, abnormal detection of the cabin pressure channel, intake pressure sensor fault detection, product gas pressure sensor fault detection, and overcurrent fault detection of 3-way solenoid valves.

[0007] Optionally, the periodic BIT detection includes detection of large differential pressure of the inlet filter, communication fault detection, abnormal detection of the cabin pressure channel, intake pressure sensor fault detection, product gas pressure sensor fault detection, pressure reducer fault detection, overcurrent fault detection of 3-way solenoid valves, low oxygen partial pressure detection, no signal detection of the oxygen partial pressure sensor, low oxygen partial pressure output detection, low oxygen concentration fault detection, and high oxygen concentration fault detection.

[0008] Optionally, when performing communication fault detection, the communication status is detected with T2 as the period. If no valid message sent by the aircraft is received within the detection period, communication fault information is output; after receiving the valid message of the aircraft, the fault is解除 (should be "cleared"). When performing abnormal detection of the cabin pressure channel, when the deviation between the cabin pressure collected by the oxygen monitor and the cabin pressure sent by the aircraft exceeds the threshold and the duration ≥ T3, abnormal fault information of the cabin pressure channel is output; when the deviation between the collected cabin pressure and the cabin pressure sent by the aircraft is less than the threshold and the duration ≥ T3, the fault is解除 (should be "cleared"). When performing intake pressure sensor fault detection, when the output voltage ≤ V1 or ≥ V2 and the duration ≥ T3, intake pressure sensor fault information is output; when the output voltage of the intake pressure sensor is 0.5V to 4.5V and the duration ≥ T3, the fault is解除 (should be "cleared"); V2 is greater than V1. When performing product gas pressure sensor fault detection, when the output voltage ≤ V1 or ≥ V2 and the duration ≥ T3, intake pressure sensor fault information is output; when the output voltage of the intake pressure sensor is V3 to V4 and the duration ≥ T3, the fault is解除 (should be "cleared"); V3 is greater than V1, and V4 is less than V2. When performing overcurrent fault detection of 3-way solenoid valves, when it is detected that the solenoid valve drive current ≥ I for T4, solenoid valve overcurrent fault information is output; when it is detected that the solenoid valve drive current < I for T3, the fault is解除 (should be "cleared").

[0009] Optionally When performing the detection of high differential pressure of the inlet filter, when the intake pressure is lower than P1 and the pressure difference between the intake pressure sent by the aircraft and the pressure collected by the intake pressure sensor is greater than P2 for a continuous T4, a fault message of high differential pressure of the filter is output to remind to replace the inlet filter; when the pressure difference is less than P2 for a continuous T3, the fault is eliminated; When performing the detection of the pressure reducer fault, when the system output pressure collected by the product gas pressure sensor is higher than P3 for a continuous T4, a fault message of the pressure reducer is output; when the system output pressure collected by the product gas pressure sensor is lower than P4 for a continuous T3, the fault is eliminated, and P4 is greater than P3.

[0010] Optionally, When performing the detection of low oxygen partial pressure, after the self-check is completed, the oxygen partial pressure value output by the on-board oxygen generation system < P5, a fault message of low oxygen partial pressure is output; when the oxygen partial pressure ≥ P8, the fault is eliminated; P8 is greater than P5, When performing the detection of no signal from the oxygen partial pressure sensor, after the self-check is completed, no output signal of the oxygen partial pressure sensor is detected after T5, a fault message of no detected signal of the oxygen partial pressure is output; when the output signal of the oxygen partial pressure sensor is detected within T4 after the self-check is completed, the fault is eliminated; When performing the detection of low output of oxygen partial pressure, after the self-check is completed, the oxygen partial pressure output by the on-board oxygen generation system < P6, a fault message of low output of oxygen partial pressure is output; when the oxygen partial pressure ≥ P7, the fault is eliminated, and P7 is greater than P6.

[0011] Optionally, When performing the detection of low oxygen concentration fault, after the self-check is completed, the oxygen concentration output by the on-board oxygen generation system < Q1, a fault message of low oxygen concentration is output; when the oxygen concentration ≥ Q2, the fault is eliminated, and Q2 is greater than Q1; When performing the detection of high oxygen concentration fault, after the self-check is completed, the oxygen concentration output by the on-board oxygen generation system > Q3, a fault message of high oxygen concentration is output; when the oxygen concentration ≤ Q4, the fault is eliminated, and Q4 is less than Q3.

[0012] The beneficial effects of the present invention are at least as follows: In the present invention, through the coupled design of power-on BIT and periodic BIT, and by reasonably setting each fault reporting logic and threshold, the system detection rate is increased by 35%, the isolation rate is increased by 30%, the false alarm rate is reduced by 40%, and the MTTR (Mean Time To Repair) is increased by 30%. Description of the Drawings

[0013] Figure 1 It is a schematic block diagram of a three-bed on-board oxygen generation system. Detailed Embodiment

[0014] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0015] The features and illustrative embodiments of various aspects of the present invention will now be described in detail. Numerous specific details are set forth in the following detailed description to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention may be practiced without requiring some of these specific details. The following description of embodiments is merely intended to provide a better understanding of the invention by illustrating examples of the invention. The invention is by no means limited to any specific setups and methods set forth below, but covers any improvements, substitutions, and modifications to structures, methods, and devices without departing from the spirit of the invention. Well-known structures and techniques are not shown in the drawings and the following description to avoid unnecessarily obscuring the invention.

[0016] It should be noted that, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other, and the various embodiments can be referenced and cited from each other.

[0017] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0018] See Figure 1 One embodiment of the present invention provides a BIT design method for a three-bed airborne oxygen generation system, applied to a three-bed airborne oxygen generation system. The system includes an inlet filter 1, an inlet pressure sensor 2, a gas source treatment device 3, a pressure reducer 4, a safety valve 5, a pneumatic valve 6, a solenoid valve 7, a molecular sieve bed 8, a flushing device 9, a gas storage tank 10, a product gas pressure sensor 11, and an oxygen monitor 12. The oxygen monitor 12 includes a cabin pressure sensor. The oxygen monitor 12 also includes an oxygen partial pressure sensor, and the pneumatic valve 6 has an intake valve and an exhaust valve. Figure 1 In the middle, the exhaust valve is located above the intake valve.

[0019] The connection relationships of the inlet filter 1, inlet pressure sensor 2, gas source treatment device 3, pressure reducer 4, safety valve 5, pneumatic valve 6, solenoid valve 7, molecular sieve bed 8, flushing device 9, gas storage tank 10, product gas pressure sensor 11, and oxygen monitor 12 in the three-bed airborne oxygen generation system can be found in relevant technologies and will not be elaborated here.

[0020] In this invention, the software of the three-bed airborne oxygen generation system is embedded in the microcontroller of the oxygen monitor 12. The software design includes initialization design, power-on status detection design, power-on countdown design, intake pressure / product gas pressure / cabin pressure detection design, oxygen partial pressure detection design, communication design, BIT design, oxygen partial pressure sensor heating control design, solenoid valve control design, data management design, and oxygen partial pressure sensor detection accuracy calibration design, etc.

[0021] The BIT design includes power-on BIT and cycle BIT design.

[0022] The power-on BIT includes communication fault detection, cabin pressure channel anomaly detection, intake pressure sensor fault detection, product air pressure sensor fault detection, and 3-way solenoid valve overcurrent fault detection.

[0023] The cycle BIT includes detection of large differential pressure in the inlet filter, communication failure, abnormal cabin pressure channel, intake pressure sensor failure, product air pressure sensor failure, pressure reducer failure, 3-way solenoid valve overflow failure, low oxygen partial pressure, no signal from oxygen partial pressure sensor, low oxygen partial pressure output, low oxygen concentration, and high oxygen concentration.

[0024] Specifically, the logic for reporting a large filter pressure difference is as follows: if the intake pressure is below 300 kPa, and the difference between the intake pressure sent by the aircraft and the pressure collected by the intake pressure sensor 2 is greater than 35 kPa for 10 seconds, a large filter pressure difference fault is reported, prompting the replacement of inlet filter 1; when the pressure difference is less than 35 kPa for 3 seconds, the fault is resolved.

[0025] The communication fault reporting logic is as follows: the communication status is checked every 1.8 seconds. If no valid message is received from the aircraft within the detection period, a communication fault is reported; after a valid message is received from the aircraft, the fault is cleared.

[0026] The cabin pressure channel malfunction reporting logic is as follows: when the cabin pressure collected by oxygen monitor 12 deviates from the cabin pressure sent by the aircraft by more than 50% or 20 kPa (whichever is greater) and the duration is ≥3s, a cabin pressure channel malfunction is reported; when the deviation between the collected cabin pressure and the cabin pressure sent by the aircraft is less than 15% or 5 kPa (whichever is less) and the duration is ≥3s, the malfunction is resolved.

[0027] The fault reporting logic for intake pressure sensor 2 is as follows: if the output voltage is ≤0.35V or ≥4.65V and the duration is ≥3s, an intake pressure sensor fault is reported; when the intake pressure sensor output voltage is 0.5V~4.5V and the duration is ≥3s, the fault is cleared.

[0028] The fault reporting logic for the air pressure sensor 11 is as follows: if the output voltage is ≤0.35V or ≥4.65V and the duration is ≥3s, an air pressure sensor fault is reported; when the air pressure sensor output voltage is 0.5V~4.5V and the duration is ≥3s, the fault is cleared.

[0029] The fault reporting logic for pressure reducer 4 is as follows: if the system output pressure collected by the product air pressure sensor 11 is higher than 450 kPa for 10 seconds, a pressure reducer fault is reported; if the system output pressure collected by the product air pressure sensor 11 is lower than 400 kPa for 3 seconds, the fault is cleared.

[0030] The logic for reporting an overcurrent fault in the 3-way solenoid valve 7 is as follows: when the solenoid valve drive current is detected to be ≥3A for 10s, an overcurrent fault is reported; when the solenoid valve drive current is detected to be <3A for 3s, the fault is cleared.

[0031] The fault logic for low oxygen partial pressure is as follows: if the oxygen partial pressure value output by the airborne oxygen generation system is <22kPa after the self-test, a low oxygen partial pressure fault is reported; if the oxygen partial pressure is ≥24kPa, the fault is resolved.

[0032] The fault reporting logic for "no oxygen partial pressure detection signal" is as follows: if no output signal from the oxygen partial pressure sensor is detected within 13 seconds after the self-test ends, an "no oxygen partial pressure detection signal" fault is reported; if an output signal from the oxygen partial pressure sensor is detected within 10 seconds after the self-test ends, the fault is resolved.

[0033] The fault reporting logic for low oxygen partial pressure output is as follows: after the self-test, if the oxygen partial pressure output of the airborne oxygen generation system is <10kPa, a low oxygen partial pressure output fault is reported; when the oxygen partial pressure is ≥18kPa, the fault is cleared.

[0034] The low oxygen concentration fault reporting logic is as follows: after the self-test, if the output oxygen concentration of the airborne oxygen generation system is <15%, a low oxygen concentration fault is reported; when the oxygen concentration is ≥18%, the fault is resolved.

[0035] The high oxygen concentration fault reporting logic is as follows: when the airborne oxygen generation system outputs an oxygen concentration >120% after the self-test, a high oxygen concentration fault is reported; when the oxygen concentration ≤110%, the fault is resolved.

[0036] In this embodiment of the invention, the fault reporting logic for communication fault detection, cabin pressure channel abnormality detection, intake pressure sensor fault detection, product air pressure sensor fault detection, and 3-way solenoid valve overcurrent fault detection in the power-on BIT can refer to the corresponding fault reporting logic in the periodic BIT, and will not be repeated here.

[0037] In practical applications, after the three-bed airborne oxygen generation system is connected to the power and gas supply, see [link to relevant documentation]. Figure 1The introduced compressed air flows through the inlet filter 1 and the air source treatment device 3. The inlet pressure sensor 2 measures the pressure after the inlet filter 1. After water removal and filtration, the gas enters the pressure reducer 4. The reduced-pressure gas then enters the pneumatic valve 6 and the solenoid valve 7. When the solenoid valve 7 is energized, the inlet valve opens and the exhaust valve closes through indirect control of the air pressure in the membrane chamber of the pneumatic valve 6, thereby pressurizing and adsorbing the molecular sieve bed 8 to output oxygen-enriched product gas. At the same time, the other two molecular sieve beds are reverse-washed through the flushing device 9. Conversely, when the solenoid valve 7 is de-energized, the inlet valve closes and the exhaust valve opens through indirect control of the air pressure in the membrane chamber of the pneumatic valve 6, thereby depressurizing and desorbing the molecular sieve bed 8. The three molecular sieve beds work in this interactive cycle, implementing the pressurization adsorption, depressurization desorption, and flushing purification process, continuously outputting oxygen-enriched product gas.

[0038] For example, after the oxygen monitor 12 is powered on, it enters a 67-second self-test. During the self-test period, it performs a power-on BIT test and, according to the fault judgment logic of this embodiment, performs communication fault detection, cabin pressure channel abnormality detection, intake pressure sensor fault detection, product gas pressure sensor fault detection, and 3-way solenoid valve overcurrent fault detection. After the 67-second self-test ends, it enters a periodic BIT test and, according to the fault judgment logic of this embodiment, performs inlet filter differential pressure detection, communication fault detection, cabin pressure channel abnormality detection, intake pressure sensor fault detection, product gas pressure sensor fault detection, pressure reducer fault detection, 3-way solenoid valve overcurrent fault detection, low oxygen partial pressure detection, oxygen partial pressure sensor no signal, low oxygen partial pressure output, low oxygen concentration, and high oxygen concentration fault detection.

[0039] The above description merely illustrates embodiments of the present invention and is quite specific and detailed; however, it should not be construed as limiting the scope of the patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention. Furthermore, any parts of the present invention not described in detail are conventional techniques.

Claims

1. A control method for a three-bed airborne oxygen generation system, characterized in that, The method includes: After the three-bed onboard oxygen generation system is connected to the power and gas source, the introduced compressed air flows through the inlet filter and gas source treatment device. The inlet pressure sensor measures the pressure after the inlet filter. After water removal and filtration, the gas enters the pressure reducer. The reduced gas then enters the pneumatic valve and the solenoid valve respectively. When the solenoid valve is energized, the inlet valve is opened and the exhaust valve is closed by indirectly controlling the air pressure in the upper chamber of the pneumatic valve membrane. This causes the molecular sieve bed to be pressurized for adsorption, outputting oxygen-enriched product gas. At the same time, the flushing device performs reverse flushing on the other two molecular sieve beds. When the solenoid valve is de-energized, the inlet valve is closed and the exhaust valve is opened by indirectly controlling the air pressure in the upper chamber of the pneumatic valve membrane. This causes the molecular sieve bed to be depressurized for desorption. The three molecular sieve beds work in this interactive cycle, implementing the pressurization adsorption, depressurization desorption, and flushing purification process, continuously outputting oxygen-enriched product gas. After the oxygen monitor is powered on, it enters a T1-second self-test, during which a power-on BIT test is performed; after the T1-second self-test ends, it enters a periodic BIT test.

2. The method according to claim 1, characterized in that, The three-bed airborne oxygen generation system includes an inlet filter, an inlet pressure sensor, a gas source treatment device, a pressure reducer, a safety valve, a pneumatic valve, a solenoid valve, a molecular sieve bed, a flushing device, a gas storage tank, a product gas pressure sensor, and an oxygen monitor. The oxygen monitor is equipped with a cabin pressure sensor and an oxygen partial pressure sensor. The pneumatic valve has an inlet valve and an exhaust valve. The software of the three-bed airborne oxygen generation system is embedded in the microcontroller of the oxygen monitor. The software of the three-bed airborne oxygen generation system is equipped with a BIT detection module, which performs power-on BIT detection and periodic BIT detection.

3. The method according to claim 2, characterized in that, The power-on BIT test includes communication fault detection, cabin pressure channel anomaly detection, intake pressure sensor fault detection, product air pressure sensor fault detection, and 3-way solenoid valve overcurrent fault detection.

4. The method according to claim 2, characterized in that, Periodic BIT testing includes detection of large differential pressure in the inlet filter, communication failure, abnormal cabin pressure channel, intake pressure sensor failure, product air pressure sensor failure, pressure reducer failure, 3-way solenoid valve overflow failure, low oxygen partial pressure, no signal from oxygen partial pressure sensor, low oxygen partial pressure output, low oxygen concentration failure, and high oxygen concentration failure.

5. The method according to claim 3 or 4, characterized in that, When performing communication fault detection, the communication status is checked in cycles of T2. If no valid message is received from the aircraft within the detection cycle, a communication fault message is output; once a valid message is received from the aircraft, the fault is cleared. When performing cabin pressure channel anomaly detection, if the deviation between the cabin pressure collected by the oxygen monitor and the cabin pressure sent by the aircraft exceeds the threshold and the duration is ≥T3, a cabin pressure channel anomaly fault information is output; if the deviation between the collected cabin pressure and the cabin pressure sent by the aircraft is less than the threshold and the duration is ≥T3, the fault is cleared. When performing the fault detection of the intake pressure sensor, if the output voltage ≤ V1 or ≥ V2 and the duration ≥ T3, the intake pressure sensor fault information is output; when the output voltage of the intake pressure sensor is 0.5V to 4.5V and the duration ≥ T3, the fault is cleared; V2 is greater than V1. When performing the fault detection of the product gas pressure sensor, if the output voltage ≤ V1 or ≥ V2 and the duration ≥ T3, the intake pressure sensor fault information is output; when the output voltage of the intake pressure sensor is V3 to V4 and the duration ≥ T3, the fault is cleared; V3 is greater than V1, and V4 is less than V2. When performing the overcurrent fault detection of the 3-way solenoid valve, if the solenoid valve drive current ≥ I is detected for T4, the solenoid valve overcurrent fault information is output; when the solenoid valve drive current < I is detected for T3, the fault is cleared.

6. The method according to claim 4, wherein When performing the detection of large differential pressure of the inlet filter, when the intake pressure is below P1 and the pressure difference between the intake pressure sent by the aircraft and the pressure collected by the intake pressure sensor is greater than P2 for T4, the filter differential pressure large fault information is output to remind to replace the inlet filter; when the pressure difference is less than P2 for T3, the fault is cleared. When performing the fault detection of the pressure reducer, if the system output pressure collected by the product gas pressure sensor is higher than P3 for T4, the pressure reducer fault information is output; when the system output pressure collected by the product gas pressure sensor is lower than P4 for T3, the fault is cleared, and P4 is greater than P3.

7. The method according to claim 4, wherein When performing the detection of low oxygen partial pressure, if the oxygen partial pressure value output by the on-board oxygen generation system after self-check < P5, the low oxygen partial pressure fault information is output; when the oxygen partial pressure ≥ P8, the fault is cleared; P8 is greater than P5. When performing the detection of no signal from the oxygen partial pressure sensor, if no output signal of the oxygen partial pressure sensor is detected after T5 from the end of self-check, the no detection signal fault information of the oxygen partial pressure is output; if the output signal of the oxygen partial pressure sensor is detected within T4 from the end of self-check, the fault is cleared. When performing the detection of low oxygen partial pressure output, if the oxygen partial pressure output by the on-board oxygen generation system after self-check < P6, the low oxygen partial pressure output fault information is output; when the oxygen partial pressure ≥ P7, the fault is cleared, and P7 is greater than P6.

8. The method according to claim 4, wherein When performing the fault detection of low oxygen concentration, if the oxygen concentration output by the on-board oxygen generation system after self-check < Q1, the low oxygen concentration fault information is output; when the oxygen concentration ≥ Q2, the fault is cleared, and Q2 is greater than Q1. When performing the fault detection of high oxygen concentration, if the oxygen concentration output by the on-board oxygen generation system after self-check > Q3, the high oxygen concentration fault information is output; when the oxygen concentration ≤ Q4, the fault is cleared, and Q4 is less than Q3.

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