Nondestructive continuous monitoring and early warning system for vehicle hydrogen carbon fiber gas cylinder

Abstract

The utility model discloses a nondestructive continuous monitoring and early warning system for a hydrogen carbon fiber gas cylinder for a vehicle, and belongs to the technical field of nondestructive monitoring and early warning of hydrogen carbon fiber gas cylinders. Comprising a main control module, an acoustic emission module, a temperature measurement module, a hydrogen concentration module, a potential detection module, a gas cylinder tank deformation detection module, a non-intrusive pressure measurement module, a flame detection module, a communication module and a power supply module, the acoustic emission module, the temperature measurement module, the hydrogen concentration module, the potential detection module, the gas cylinder tank deformation detection module, the non-intervention pressure measurement module, the flame detection module, the communication module and the power supply module are connected with the main control module. The device works in a lossless and non-intervention mode, does not change an original high-pressure hydrogen working loop, and works in an independent mode. The device is portable in volume, is designed in an intrinsically safe manner, and can carry out real-time uninterrupted monitoring and early warning on the gas cylinder for the vehicle.

Description

Technical Field

[0001] The utility model belongs to the technical field of non-destructive monitoring and early warning of hydrogen carbon fiber cylinders, and specifically relates to a non-destructive continuous monitoring and early warning system for vehicle hydrogen carbon fiber cylinders. Background Technique

[0002] In hydrogen energy vehicles with fuel cells as the power core, compressed hydrogen has received the most attention and is technically simple and feasible. Compressed hydrogen storage mainly uses high-pressure cylinders. Considering issues such as the weight of the vehicle body power system, the current compressed hydrogen storage tanks are mainly carbon fiber fully wound composite cylinders, which can be further divided into two types: metal aluminum inner liners and special plastic inner liners according to different internal structures of the cylinders. Due to the physical and chemical properties of hydrogen, it is prone to leakage and explosion. Therefore, the safety of compressed hydrogen storage cylinders becomes extremely important. The regular inspection and evaluation of cylinders are interval-based assessments of the cylinder status, while in the actual operation of hydrogen energy vehicles, the status of the cylinders lacks real-time and effective monitoring. Real-time and uninterrupted monitoring and early warning are required for carbon fiber fully wound composite cylinders of hydrogen energy vehicles, as well as regular inspection and evaluation of the cylinders. The existing detection methods are as follows:

[0003] 1. Image analysis, or combined with pressure change parameters:

[0004] CN116465575A A method and system for diagnosing the faults of the cylinder body of a carbon fiber fully wound hydrogen storage cylinder

[0005] CN115494092A A non-destructive detection method and system for carbon fiber cylinders based on a fast convolutional neural network

[0006] 2. Sound sensors, acoustic emission sensors:

[0007] CN115060429A A monitoring system, method and fuel cell vehicle for a gas storage cylinder

[0008] CN113686969A An on-line structural health monitoring system and monitoring method for vehicle-mounted hydrogen storage cylinders

[0009] CN104614448A A method for extracting acoustic emission characteristic signals of a carbon fiber reinforced aluminum inner liner composite cylinder

[0010] CN114993862A A fatigue detection method and fatigue detection component for high-pressure cylinders

[0011] 3. Microwave detection method, establishing cylinder defect data according to the characteristics of reflected waves:

[0012] CN114813789A A method for detecting defects of a carbon fiber wound type IV hydrogen storage cylinder

[0013] 4. Fiber optic winding type, judging the volume change of the cylinder, fiber optic temperature measurement, combined with the pressure inside the cylinder:

[0014] CN114659029A A hydrogen storage and transportation safety monitoring system and its monitoring method

[0015] CN215811595U A device for detecting the health status of a carbon fiber wound gas cylinder

[0016] CN113757552A A carbon fiber wound gas cylinder and its health status monitoring method

[0017] CN110469772A A non-destructive testing device and method for hydrogen cylinders

[0018] Existing storage and transportation safety monitoring systems, their monitoring methods, defect judgment and determination methods and devices have the following problems: Some methods are not suitable for real-time vehicle monitoring. For example, in the image analysis method, it can only be carried out in an annual inspection mode, involving gas cylinder pressure tests, X-ray imaging, etc.; Some methods require invasive acquisition of the pressure signal inside the gas cylinder and need to be connected to high-pressure pipelines, increasing uncertain safety factors; Some methods such as fiber optic winding require embedding or later winding of optical fibers inside or on the surface of the gas cylinder during the gas cylinder processing stage, increasing the production difficulty and cost of the gas cylinder, the later maintenance cost of the gas cylinder, etc.; Some methods such as microwave detection lack the accumulation of industry data and need further verification; Some methods such as sound sensors detect ultrasound, and the detection method is relatively single; Acoustic emission sensors have a certain distance from the application field of automotive gas cylinders.

[0019] For vehicle-mounted compressed hydrogen carbon fiber fully wound composite gas cylinders, their non-destructive continuous monitoring and early warning of the state must also be multi-angle and multi-parameter. It is necessary to start from multiple aspects such as the damage characteristics of the carbon fiber wound on the gas cylinder, pressure changes, tank deformation, electrostatic discharge paths, tank temperature, hydrogen leakage, and accumulation of waste hydrogen from fuel cells, perform real-time online detection of the gas cylinder, and realize functions such as early damage of abnormal states of the gas cylinder, early warning of approaching damage, and risk control. Summary of the Invention

[0020] To solve the above problems, the present utility model proposes: A non-destructive continuous monitoring and early warning system for vehicle-mounted hydrogen carbon fiber gas cylinders, including a main control module, an acoustic emission module, a temperature measurement module, a hydrogen concentration module, a potential detection module, a gas cylinder tank deformation detection module, a non-invasive pressure measurement module, a flame detection module, a communication module, and a power supply module. The acoustic emission module, temperature measurement module, hydrogen concentration module, potential detection module, gas cylinder tank deformation detection module, non-invasive pressure measurement module, flame detection module, communication module, and power supply module are connected to the main control module.

[0021] Further, the main control module, acoustic emission module, temperature measurement module, hydrogen concentration module, potential detection module, gas cylinder body deformation detection module, non-invasive pressure measurement module, flame detection module, power supply module, and communication module are located in a housing made of metal material. The lower part of the housing is equipped with a gas cylinder shape adapter that fits and connects with the gas cylinder, and is filled and sealed with epoxy explosion-proof glue. The housing is reliably connected to the vehicle grounding strap through a silver-plated braided wire.

[0022] Further, acoustic emission sensor windows and transmitting and receiving ultrasonic probe windows are opened in the lower part of the housing. The acoustic emission sensor and the ultrasonic probe are coupled and connected to the outer wall of the gas cylinder through an acoustic couplant; the hydrogen sensor and the communication module antenna are located in the upper part of the metal housing. The temperature measurement probe, the gas cylinder body deformation detection module probe, the external power supply lead wire, the contact resistance measurement lead wire, and the flame detection probe are led out through an aviation explosion-proof socket, and the aviation explosion-proof socket is located outside the housing; the elastic fixing structure is composed of elastic fixing bands, and the two fixing bands are respectively fixed at the edge positions on both sides of the housing; the temperature measurement probe and the gas cylinder body deformation detection module probe are fixed inside the elastic fixing band. When the fixing band is fixed to the gas cylinder body, the temperature measurement probe and the body deformation detection module probe are in close contact with the outer wall of the gas cylinder, and the probe wires are located outside the fixing band; the flame detection probe faces the joint of the gas cylinder and the valve body; the external power supply lead wire is connected to the vehicle 12V power supply system; the potential detection measurement probe is composed of a contact resistance measurement probe and a ground potential measurement probe; the contact resistance measurement probe is composed of two lead wires, one lead wire is fixed at the metal position of the external valve or conduit of the gas cylinder, and one lead wire is fixed to the vehicle grounding strap; the ground potential measurement probe is a high-insulation electric field probe and is located under the metal body of the vehicle chassis.

[0023] Further, the acoustic emission module includes an acoustic emission sensor, a low-noise coaxial connection cable, a preamplifier, a filter, and a controllable gain amplifier. The acoustic emission probe is a 1045S broadband sensor, which is connected to a weak current-voltage conversion circuit with LTC6244 as the core through a low-noise coaxial connection cable with a semiconductor shielding layer. It is a negative feedback current preamplifier structure based on a high-value resistor and has a high input impedance characteristic. It converts the weak current generated by the acoustic emission sensor into a voltage quantity, and the converted voltage quantity is connected to the controllable gain amplifier AD620 for further amplification. The Vref1 in the circuit sets the reference DC voltage, which is filtered by an RC filter and then output, and the output signal is sent to the high-speed analog-to-digital converter in the main control module.

[0024] Further, the temperature measurement module is composed of a PT100 temperature measurement probe, a shielded connection cable, and a resistance measurement circuit. The PT100 temperature measurement probe is connected to the resistance measurement circuit through a shielded connection cable. A high-precision 1mA constant current source passes through the resistance to be measured, and the instrumentation amplifier AD8220 is used to realize differential-to-single-ended buffered output of the corresponding analog voltage signal.

[0025] Further, the potential detection module is composed of two functional circuits: contact resistance measurement and ground potential measurement. The contact resistance measurement functional circuit is composed of a contact resistance measurement lead, a shielded connection cable, and a resistance measurement circuit. The contact resistance measurement lead is connected to the resistance measurement circuit through the shielded connection cable. The ground potential measurement functional circuit is an electrometer circuit, which is a current-voltage conversion circuit structure composed of a high-input impedance operational amplifier LMC6002 and a high-value resistor.

[0026] Further, the hydrogen concentration module is a catalytic MEMS chip SMD1012. The module is equipped with a heater power supply and a test voltage source. The analog output voltage is buffered by an operational amplifier and then output. The MEMS chip is located inside a protective cover shell with waterproof, explosion-proof, and fire-resistant functions.

[0027] Further, the cylinder body deformation detection module is composed of a cylinder body deformation detection module probe, a shielded connection cable, and a resistance measurement circuit. The cylinder body deformation detection module probe is connected to the resistance measurement circuit through the shielded connection cable. The cylinder body deformation detection module probe is a bending sensor with the model of flex4.5. When the bending sensor bends outward, the resistance of the sensor changes. By detecting the bending sensor of the probe, the resistance change is converted into a voltage change, indirectly reflecting the deformation of the cylinder body of the gas cylinder.

[0028] Further, the non-invasive pressure measurement module is composed of a split ultrasonic transmitting probe U1, a receiving probe U2, an ultrasonic transmitting drive, and a receiving circuit. The ultrasonic transmitting probe U1, the ultrasonic transmitting drive, the receiving circuit, and the receiving probe U2 are connected in sequence. An operational amplifier is used to amplify the signal of the ultrasonic receiving probe. An audio power amplifier chip is used to drive the ultrasonic transmitting probe. An amplification circuit is composed of an AD8552 operational amplifier. For the ultrasonic transmitting drive, an audio power amplifier chip TDA1308 is used to drive the ultrasonic transmitting probe.

[0029] Further, the flame detection module uses infrared and ultraviolet photodiodes and works in a three-band dot mode. The infrared and ultraviolet photodiodes output weak current signals, which are converted into voltage signals through a current-voltage conversion circuit, and then further converted into a pulse form of TTL level through a comparator circuit. The output signal of the module is input into the main control module through an interrupt method to detect the micro-flame of hydrogen.

[0030] The beneficial effects of the present utility model are as follows:

[0031] The utility model can perform real-time monitoring on multiple parameters of a vehicle-use compressed hydrogen carbon fiber fully wound composite gas cylinder, such as damage to the carbon fiber wound on the gas cylinder, pressure change, deformation of the cylinder body, electrostatic discharge path, cylinder body temperature, external hydrogen concentration, and micro-flames. It is small in size and closely adheres to the gas cylinder, with little impact on the use and maintenance of the gas cylinder. The intrinsically safe design does not introduce additional safety hazards. It can give early warnings for abnormal states such as early damage, near failure, and leakage of the gas cylinder, further reminding the vehicle driver to inspect and evaluate the gas cylinder, reducing the probability of accidents, and conforming to the concept of preventive maintenance.

[0032] The utility model relates to a non-destructive continuous monitoring and warning system for a vehicle-use compressed hydrogen carbon fiber fully wound composite gas cylinder (hereinafter referred to as the gas cylinder). The system is composed of a main control module, an acoustic emission module, a temperature measurement module, a hydrogen concentration module, a contact resistance measurement module, a cylinder body deformation detection module, a non-invasive pressure measurement module, a flame detection module, a communication module, an elastic fixing structure, etc. The utility model detects the acoustic signals emitted when the winding fibers of the gas cylinder are damaged through the acoustic emission module, measures the surface temperature of the gas cylinder through the temperature measurement module, measures the external hydrogen concentration of the gas cylinder through the hydrogen concentration module, measures the contact resistance between the cylinder body and the vehicle body through the contact resistance measurement module, measures the shape change of the cylinder body caused by deformation through the cylinder diameter detection module, measures the internal pressure of the gas cylinder in an indirect way through the non-invasive pressure measurement module, and detects the micro-flames existing due to slight leakage combustion through the flame detection module. The main control module combines the information of the above modules to judge the real-time state of the gas cylinder in a non-destructive manner, and gives an alarm signal when an abnormal situation occurs, reminding the vehicle driver to inspect and evaluate the gas cylinder, reducing the probability of possible accidents.

[0033] Determined by the working principle, the utility model works in a non-destructive and non-invasive manner, does not change the original high-pressure hydrogen working circuit, and works independently. The utility model is portable in volume and is designed in an intrinsically safe manner, capable of performing real-time and continuous monitoring and warning on in-use vehicle gas cylinders. Description of the Drawings

[0034] Figure 1 It is the system function structure diagram of the utility model;

[0035] Figure 2 It is the circuit diagram of the acoustic emission module of the utility model;

[0036] Figure 3 It is the resistance measurement circuit diagram of the temperature measurement module of the utility model;

[0037] Figure 4 It is the circuit diagram of the ultrasonic emission and reception module of the utility model;

[0038] Figure 5 It is the external shape structure diagram of the utility model;

[0039] Figure 6 This is the structural diagram of the bottom of the shell of the present utility model. Specific embodiments

[0040] To make the technical means and achieved purposes adopted by the present utility model easy to understand, the present utility model, a non-destructive continuous monitoring and warning system for a vehicle hydrogen carbon fiber gas cylinder, is further described below in conjunction with specific embodiments. The system is composed of a main control module, an acoustic emission module, a temperature measurement module, a hydrogen concentration module, a potential detection module, a gas cylinder body deformation detection module, a non-invasive pressure measurement module, a flame detection module, a communication module, a power supply module, an elastic fixing structure, etc., and the functional structure is as Figure 1 shown. In the present utility model, the main control module, the acoustic emission module, the temperature measurement module, the hydrogen concentration module, the potential detection module, the gas cylinder body deformation detection module, the non-invasive pressure measurement module, the flame detection module, the power supply module, and the communication module are located in a functional shell made of metal material (hereinafter referred to as the shell). The lower part of the shell is equipped with a gas cylinder shape adapter that can fit well with the gas cylinder, and is filled and sealed with epoxy explosion-proof glue to achieve the purpose of explosion protection. The shell is reliably connected to the vehicle grounding strap through a silver-plated braided wire.

[0041] An acoustic emission sensor window and an ultrasonic probe transmitting and receiving window are opened in the lower part of the shell. The corresponding windows are opened at the corresponding positions of the shell to ensure that the sensor can protrude from the outer shell and fit tightly with the gas cylinder to be detected. The acoustic emission sensor and the ultrasonic probe are well coupled with the outer wall of the gas cylinder through an acoustic coupling agent. The hydrogen sensor and the communication module antenna are located on the upper part of the metal shell. The temperature measurement probe, the gas cylinder body deformation detection module probe, the external power lead, the contact resistance measurement lead, and the flame detection probe are led out through an aviation explosion-proof socket, and the aviation explosion-proof socket is located outside the shell. The elastic fixing structure is composed of elastic fixing belts. The two fixing belts are respectively fixed at the two side edge positions of the shell. The temperature measurement probe and the gas cylinder body deformation detection module probe are fixed on the inner side of the elastic fixing belt. When the fixing belt is fixed to the gas cylinder body, the temperature measurement probe and the body deformation detection module probe fit well with the outer wall of the gas cylinder, and the probe wires are located on the outer side of the fixing belt. The flame detection probe faces the joint of the gas cylinder and the valve body. The external power lead is connected to the vehicle 12V power supply system. The potential detection measurement probe is composed of two parts: a contact resistance measurement probe and a ground potential measurement probe. The contact resistance measurement probe is composed of two leads. One lead is fixed at the metal position of the external valve or conduit of the gas cylinder, and one lead is fixed to the vehicle grounding strap; the ground potential measurement probe is a high-insulation electric field probe and is located below the metal body of the vehicle chassis.

[0042] In the present utility model, as Figure 2As shown in the figure, the acoustic emission module consists of an acoustic emission sensor, a low-noise coaxial connecting cable, a preamplifier, a filter, a controllable gain amplifier, etc. The acoustic emission sensor is a 1045S broadband sensor, which is connected to a weak current-voltage conversion circuit with LTC6244 as the core through a low-noise coaxial connecting cable with a semiconductor shielding layer. It is a negative feedback current preamplifier structure based on a high-value resistor, with high input impedance characteristics, which can convert the weak current generated by the acoustic emission sensor into a voltage quantity. The converted voltage quantity is connected to the controllable gain amplifier AD620 for further amplification to an appropriate amplitude. In the circuit, Vref1 sets an appropriate reference DC voltage, which is filtered by the RC filter and then output to ensure that the output signal meets the requirements of the high-speed analog-to-digital converter of the main control module.

[0043] As Figure 3 shown in the figure, the temperature measurement module consists of 4 PT100 temperature measurement probes, a shielded connecting cable, and a resistance measurement circuit. Considering that the length of the PT100 lead wire is appropriate in the application of the utility model, a three-wire PT100 measurement circuit can be used to cooperate with an instrumentation amplifier to simplify the circuit structure and achieve high measurement accuracy. Taking one path of the resistance measurement circuit as an example, a high-precision 1mA constant current source passes through the resistance to be measured, and the instrumentation amplifier AD8220 is used to realize differential-to-single-ended buffered output of the corresponding analog voltage signal. In the circuit, the reference voltage V ref2 sets an appropriate value to eliminate the resistance value corresponding to -50°C of the PT100, ensuring a measurement range of -50°C to 150°C and a temperature measurement accuracy of 0.2°C for the temperature measurement circuit. The four PT100 measurement circuits have the same structure and function.

[0044] The potential detection module consists of two functional circuits: contact resistance measurement and ground potential measurement. The contact resistance measurement functional circuit consists of a contact resistance measurement lead, a shielded connecting cable, and a resistance measurement circuit. The resistance measurement circuit is the same as Figure 3 that, and the reference input voltage is 0V. By measuring the resistance between the metal part of the gas cylinder and the vehicle frame grounding strap, the reliability of the static electricity release path is judged to ensure that the contact resistance is less than 100Ω. The circuit has a disconnection detection function. The ground potential measurement functional circuit is an electrometer circuit, and its core is a current-voltage conversion circuit structure composed of a high-input impedance operational amplifier LMC6002 and a high-value resistor.

[0045] The ground potential measurement probe is used to measure the electric field gradient distribution between the metal chassis of the vehicle and the road surface during vehicle driving, measure the static electricity accumulation degree of the vehicle body to the road surface, and evaluate the effective working state of the vehicle static electricity belt.

[0046] The hydrogen concentration module takes the catalytic MEMS chip SMD1012 as the core. The module is equipped with a heater power supply and a test voltage source inside. The analog output voltage is buffered by an operational amplifier and then output. The MEMS chip is located inside a protective cover shell with functions of waterproofing, explosion-proofing, and fire resistance. The module has a range of 5000 ppm and a resolution of 1 ppm, and has a certain anti-interference ability.

[0047] The cylinder body deformation detection module consists of a cylinder body deformation detection module probe, a shielded connection cable, and a resistance measurement circuit. The cylinder body deformation detection module probe is a bending sensor with the model flex4.5. When the bending sensor bends outward, the resistance of the sensor changes. The resistance measurement circuit Figure 3 has a reference input voltage of 0 V and a constant current drive of 0.1 mA. By detecting the bending sensor of the probe, the resistance change is converted into a voltage change, indirectly reflecting the possible deformation of the cylinder body.

[0048] As Figure 4 shown, the non-invasive pressure measurement module consists of a split ultrasonic transmitting probe U1, a receiving probe U2, an ultrasonic transmitting drive, and a receiving circuit. The probe model is waterproof. Since it is necessary to transmit and receive waveform data containing phase relationships in an analog manner, an operational amplifier is used to amplify the signal of the ultrasonic receiving probe, and an audio power amplifier chip is used to drive the ultrasonic transmitting probe. The ultrasonic reflected echo signal is weak, and an amplification circuit with an amplification factor of about 1000 and a certain adjustment ability is formed by using the AD8552 operational amplifier. For the ultrasonic transmitting drive, an audio power amplifier chip TDA1308 is used to drive the ultrasonic transmitting probe, and the drive wave Vref3 is generated by the low-speed DAC converter of the main control module, and the reference voltage Vref4 is provided by the main control module.

[0049] The flame detection module is based on infrared and ultraviolet photosensitive diodes and works in a three-band dot mode. The infrared and ultraviolet photosensitive diodes output weak current signals, which are converted into voltage signals through a current-voltage conversion circuit similar to Figure 2 and then further converted into pulse form of TTL level through a comparator circuit. The output signal of the module is input to the main control module through the interrupt mode. It can detect the hydrogen micro-flame that is difficult to observe with the naked eye and does not have strong heat radiation characteristics.

[0050] The communication module is a Bluetooth module based on the low-power Bluetooth BLE5.2 protocol. Based on the NRF52840 chip, it works in the wireless serial port mode and communicates with the main control module through the serial port mode.

[0051] The main control module takes STM32H747 as the core. STM32H747 has a frequency of 480 MHz, 2 12-bit DACs, and 3 ADCs (the maximum resolution is 16 bits, and the sampling rate is 3.6 Msps). One-way DAC outputs a fixed value voltage V ref2to the temperature measurement module, and one path of DAC outputs V ref3 a linear frequency-swept signal of wide rectangular pulses. One path of ADC collects the output signal out1 of the acoustic emission module, one path of ADC collects the output signal out2 of the non-invasive pressure measurement module, and one path of ADC cooperates with an analog switch and an input buffer operational amplifier follower to collect the outputs of the gas cylinder body deformation detection module, contact resistance measurement module, temperature measurement module, and hydrogen concentration module. The reference voltage V ref4 is obtained by the internal reference voltage of STM32H747 through output, voltage division, and buffering.

[0052] The power supply module filters, isolates, steps down, etc. the vehicle-mounted 12V power supply to provide corresponding working power supplies for the internal digital circuits and analog circuits of the utility model. Since the power supply module is a basic module and is connected to all other modules, Figure 1 it will not be specified further.

[0053] Method description

[0054] The vehicle-mounted compressed hydrogen storage tank body is a composite gas cylinder fully wound with carbon fiber. The gas cylinder is made of an aluminum inner liner or a plastic inner liner, with carbon fiber wound on the outside and cured with epoxy resin. Due to wear, scratch, impact, overheating, corrosion, aging, leakage, etc., the gas cylinder may be damaged, such as cracking, fiber fracture and separation, inner liner winding layer separation, bulging, buckling, inner liner deformation, etc. In severe cases, it may cause functional failure and pose a considerable danger. In response to the above possible gas cylinder damage phenomena, the utility model starts from aspects such as acoustic emission, temperature, deformation, leakage, pressure, static electricity, and micro-flame, and comprehensively monitors the possible failure characteristic signals of the gas cylinder in real time.

[0055] In practical applications, the acoustic emission signals generated by defects in storage tanks and pressure vessels generally have frequencies in the range of 100 kHz to 300 kHz. The acoustic emission signals generated by defects in carbon fiber - composite materials generally have higher frequencies in the range of 300 kHz to 1000 kHz. The acoustic emission signals caused by high - pressure gas leakage generally have lower frequencies in the range of 10 kHz to 70 kHz. The above acoustic emission characteristics respectively correspond to the inner liner breakage, carbon fiber breakage, and hydrogen leakage of the gas cylinder. Due to the limited volume of on - vehicle gas cylinders, a single broadband acoustic emission sensor 1045S is used to collect signals in the frequency band of 30 kHz to 1200 kHz for real - time continuous monitoring to capture the characteristic signals of newly emerging active defects. The acoustic emission signals are affected by the geometric shape of the gas cylinder, and the propagation and attenuation are relatively complex, so the collected waveforms are also relatively complex. The signal input part of the acoustic emission sensor is realized by an analog circuit, and data acquisition, signal processing, etc. are carried out in a fully digital manner. For the acoustic emission characteristics, a neural network deep - learning method is used to directly qualitatively judge the nature and severity of the acoustic emission. For the acoustic emission data characteristics of the present utility model, which appear as fixed - length sequence data, a convolutional neural network can automatically learn meaningful features from the signals. The STM32Cube.AI toolkit is used to achieve data capture, data annotation, neural network training, and convert the model into C code to run on the STM32 microcontroller. The relevant training data are collected from gas cylinder type tests, annual inspection tests, pressure failure tests, leakage tests, etc.

[0056] Through the PT100 probes and deformation detection probes arranged on the inner surface of the elastic fixed structure and closely attached to the outer surface of the gas cylinder, the data acquisition of the temperature at 4 points on the outer surface of the gas cylinder and the deformation of 4 regions is completed; the hydrogen concentration module is used to measure the hydrogen concentration in the air above the tank body; the potential detection module is used to measure the contact resistance between the gas cylinder and the vehicle grounding strap and obtain the static electricity accumulation situation of the vehicle body to ensure a reliable discharge path for the static electricity accumulation of the gas cylinder and its supporting equipment. The flame detection module is used to detect the micro - leakage and possible micro - flame combustion phenomena that may occur in the gas cylinder, valve body, and pipeline due to long - term use and aging, and detect the occurrence of micro - flames in a timely manner. The main control module monitors the temperature data of the tank body to ensure that it works within the recommended range; monitors the data of the deformation detection module to basically ensure that there is no large deformation of the tank body; monitors the hydrogen concentration signal to timely detect abnormal increases in the external hydrogen concentration caused by reasons such as hydrogen leakage and cumulative waste hydrogen emissions; monitors the signal of the flame detection module to timely detect micro - flame phenomena.

[0057] The non-invasive pressure measurement module uses the time difference method and measures the reflection time difference of specific emitted ultrasonic waves passing through the gas-solid interface twice by means of ultrasonic longitudinal wave reflection. Combining parameters such as the cylinder size, hydrogen concentration, temperature, and density, the pressure inside the cylinder is calculated. Since the ultrasonic probe is closely attached to the outer surface of the cylinder, the pulse compression / matching filtering method is adopted to improve the measurement accuracy. In the application of the present utility model, due to the clear relevant parameters of the cylinder and the lack of obvious fluidity and other characteristics, the non-invasive measurement method can achieve relatively high measurement accuracy in a relatively simple manner. Combining with the pressure value inside the cylinder, especially paying attention to the characteristics of acoustic emission signals near the Felicity ratio (95% filling pressure), it can better indicate the abnormal conditions of the cylinder.

[0058] The external structure of the utility model is as Figures 5 - 6 shown:

[0059] The utility model shell has a total of 4 fixing ears and two elastic fixing straps. Only one elastic fixing strap is marked in Figure 5 the figure, and the structure of the other fixing strap is the same.

[0060] When the present utility model is applied, the functional shell is fixed on the cylinder through an elastic fixing structure. The external temperature and deformation detection probes are connected to the functional shell through explosion-proof aviation sockets, the grounding wire is reliably connected to the vehicle grounding strap, and the external power supply lead is connected to the vehicle power supply system. When the utility model is started, it continuously collects signals such as acoustic emission, pressure, temperature, contact resistance, potential, deformation amount, hydrogen concentration, and micro-flame in real time. The main control unit judges the operating state of the cylinder according to specific procedures and uploads the information to the vehicle-mounted information display terminal through Bluetooth communication, completing functions such as status detection and danger warning, reminding the driver to conduct cylinder safety inspections when necessary, reducing the probability of accidents, and playing a positive social and economic benefit.

[0061] The above is only the preferred specific embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present utility model, according to the technical solution and its concept of the present utility model, makes equivalent substitutions or changes, and all should be covered within the protection scope of the present utility model.

Claims

1. A non-destructive continuous monitoring and early warning system for vehicle hydrogen carbon fiber gas cylinders, characterized in that, It includes a main control module, an acoustic emission module, a temperature measurement module, a hydrogen concentration module, a potential detection module, a cylinder body deformation detection module, a non-invasive pressure measurement module, a flame detection module, a communication module, and a power supply module. The acoustic emission module, temperature measurement module, hydrogen concentration module, potential detection module, cylinder body deformation detection module, non-invasive pressure measurement module, flame detection module, communication module, and power supply module are connected to the main control module; the main control module, acoustic emission module, temperature measurement module, hydrogen concentration module, potential detection module, cylinder body deformation detection module, non-invasive pressure measurement module, flame detection module, power supply module, and communication module are located in a housing made of metal material. The lower part of the housing is equipped with a cylinder shape adapter that fits and connects with the cylinder, and is filled and sealed with epoxy explosion-proof glue. The housing is reliably connected to the vehicle grounding strap through a silver-plated braided wire; The lower part of the housing is provided with an acoustic emission sensor window and a transmitting and receiving ultrasonic probe window. The acoustic emission sensor and the ultrasonic probe are coupled and connected to the outer wall of the cylinder through an acoustic couplant; the hydrogen sensor and the communication module antenna are located in the upper part of the metal housing. The temperature measurement probe, the cylinder body deformation detection module probe, the external power lead, the contact resistance measurement lead, and the flame detection probe are led out through an aviation explosion-proof socket, and the aviation explosion-proof socket is located outside the housing; the elastic fixing structure is composed of elastic fixing bands, and the two fixing bands are respectively fixed at the edge positions on both sides of the housing; the temperature measurement probe and the cylinder body deformation detection module probe are fixed inside the elastic fixing band. When the fixing band is fixed to the cylinder body, the temperature measurement probe and the cylinder body deformation detection module probe are in contact and connected with the outer wall of the cylinder, and the probe wires are located outside the fixing band; the flame detection probe is directed towards the joint of the cylinder and the valve body; the external power lead is connected to the vehicle 12V power supply system; the potential detection measurement probe is composed of a contact resistance measurement probe and a ground potential measurement probe.

2. The non-destructive continuous monitoring and early warning system for vehicle hydrogen carbon fiber gas cylinders according to claim 1, characterized in that The contact resistance measurement probe is composed of two leads. One lead is fixed at the metal position of the external valve or conduit of the cylinder, and one lead is fixed to the vehicle grounding strap; the ground potential measurement probe is a high-insulation electric field probe and is located below the metal body of the vehicle chassis.

3. The non-destructive continuous monitoring and early warning system for vehicle hydrogen carbon fiber gas cylinders according to claim 1, characterized in that, The acoustic emission module includes an acoustic emission sensor, a low-noise coaxial connecting cable, a preamplifier, a filter, and a controllable gain amplifier. The acoustic emission probe is a 1045S broadband sensor, which is connected to a weak current-voltage conversion circuit with LTC6244 as the core through a low-noise coaxial connecting cable with a semiconductor shielding layer. It is a negative feedback current preamplifier structure based on a high-value resistor, with high input impedance characteristics, converting the weak current generated by the acoustic emission sensor into a voltage quantity. The converted voltage quantity is connected to the controllable gain amplifier AD620 to further amplify the amplitude. In the circuit, V ref1 A reference DC voltage is set, filtered by an RC filter and then output. The output signal is sent to the high-speed analog-to-digital converter of the main control module.

4. The non-destructive continuous monitoring and early warning system for vehicle hydrogen carbon fiber gas cylinders according to claim 1, characterized in that, The temperature measurement module is composed of a PT100 temperature measurement probe, a shielded connection cable, and a resistance measurement circuit. The PT100 temperature measurement probe is connected to the resistance measurement circuit through the shielded connection cable. A high-precision 1mA constant current source is passed through the resistance to be measured, and the instrument amplifier AD8220 is used to realize differential-to-single-ended buffered output of the corresponding analog voltage signal.

5. The non-destructive continuous monitoring and early warning system for vehicle hydrogen carbon fiber gas cylinders according to claim 1, characterized in that, The potential detection module is composed of two functional circuits: contact resistance measurement and ground potential measurement. The contact resistance measurement functional circuit is composed of a contact resistance measurement lead, a shielded connection cable, and a resistance measurement circuit. The contact resistance measurement lead is connected to the resistance measurement circuit through the shielded connection cable; the ground potential measurement functional circuit is an electrometer circuit, which is a current-voltage conversion circuit structure composed of a high-input impedance operational amplifier LMC6002 and a high-value resistor.

6. The non-destructive continuous monitoring and early warning system for vehicle hydrogen carbon fiber gas cylinders according to claim 1, characterized in that, The hydrogen concentration module is a catalytic MEMS chip SMD1012. The module is equipped with a heater power supply and a test voltage source. The analog output voltage is buffered by an operational amplifier and then output. The MEMS chip is located inside a protective cover shell with waterproof, explosion-proof, and fire-resistant functions.

7. The non-destructive continuous monitoring and early warning system for vehicle hydrogen carbon fiber gas cylinders according to claim 1, characterized in that The cylinder body deformation detection module consists of a cylinder body deformation detection module probe, a shielded connection cable, and a resistance measurement circuit. The cylinder body deformation detection module probe is connected to the resistance measurement circuit through the shielded connection cable. The cylinder body deformation detection module probe is a bending sensor with the model flex4.

5. When the bending sensor bends outward, the resistance of the sensor changes. By detecting the bending sensor of the probe, the resistance change is converted into a voltage change, indirectly reflecting the deformation of the cylinder body of the gas cylinder.

8. The non-destructive continuous monitoring and early warning system for vehicle hydrogen carbon fiber gas cylinders according to claim 1, wherein The non-invasive pressure measurement module consists of a split ultrasonic transmitting probe U1, a receiving probe U2, and an ultrasonic transmitter drive and receiving circuit; the ultrasonic transmitting probe U1, the ultrasonic transmitter drive and receiving circuit, and the receiving probe U2 are connected in sequence. An operational amplifier is used to amplify the signal of the ultrasonic receiving probe, and an audio power amplifier chip is used to drive the ultrasonic transmitting probe; an amplifier circuit is formed using the AD8552 operational amplifier; for the ultrasonic transmitter drive, the audio power amplifier chip TDA1308 is used to drive the ultrasonic transmitting probe.

9. The non-destructive continuous monitoring and early warning system for vehicle hydrogen carbon fiber gas cylinders according to claim 1, characterized in that, The flame detection module uses infrared and ultraviolet photodiodes and operates in a three-band dot mode. The infrared and ultraviolet photodiodes output weak current signals, which are converted into voltage signals through a current-voltage conversion circuit and then further converted into a pulse form of TTL level through a comparator circuit. The output signal of the module is input to the main control module through an interrupt method to detect the hydrogen micro-flame.

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