Hydrogen Leak Detection System and Method for Hydrogen Fuel Vehicles with Mixing Devices

Abstract

The present invention belongs to the technical field of hydrogen leakage detection for hydrogen fuel vehicles, and discloses a hydrogen leakage detection system for hydrogen fuel vehicles with a mixing device, which includes a heat preservation cabin body for constructing a closed space. The heat preservation cabin body is connected with an intake air fan, a hydrogen concentration sensor, a sunlight simulation system, a vertical mixing fan, an adjusting airbag, a horizontal mixing fan, a gate and an inflatable sealing ring. In the present invention, mixing fans are arranged in the horizontal and vertical directions of the heat preservation cabin body to make the distribution of hydrogen in the closed space uniform; an adjusting airbag is set to keep the air pressure in the closed space stable; the present invention calculates the leakage mass of hydrogen based on the hydrogen leakage mass quantification method, and the obtained hydrogen leakage amount result data is accurate and has good repeatability, which is applicable to the detection of hydrogen leakage of hydrogen fuel vehicles.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrogen leakage detection for hydrogen fuel vehicles, and particularly to a hydrogen leakage detection system and method for hydrogen fuel vehicles with a mixing device. Background Art

[0002] The fuel of a hydrogen fuel vehicle is hydrogen stored in a hydrogen storage device at a pressure of 35 MPa or 70 MPa. Due to the small size, low density, strong diffusion ability, strong penetration and hydrogen quenching effect of hydrogen molecules, hydrogen is extremely prone to leakage; moreover, hydrogen also has characteristics such as flammability and explosiveness. Therefore, under the combined action of high-pressure storage, hydrogen leakage has become a major safety hazard for hydrogen fuel vehicles. To avoid this hazard, in the current safety technical standards for hydrogen fuel vehicles, a hydrogen leakage test procedure in a closed space based on hydrogen sensor concentration detection is proposed, that is, a hydrogen fuel vehicle filled with hydrogen to the nominal pressure is placed statically in a closed space with an ambient temperature of 25 °C for 12 h, and then the closed space is sealed for hydrogen leakage testing; when the detected concentration of any one of the 7 hydrogen sensors evenly arranged at the top of the closed space exceeds 1% by volume, the hydrogen leakage of the vehicle is unqualified. However, the existing method is based on concentration detection and has two main drawbacks:

[0003] 1) After leakage occurs, there is a hydrogen concentration gradient in the vertical direction. When the time interval between the leakage occurrence moment and the reading of the hydrogen sensor detection value is short, the leaked hydrogen does not have enough time to diffuse to the vicinity of the hydrogen sensor located at the top under the static condition in the closed space, resulting in inaccurate detection of the leakage concentration.

[0004] 2) For the same hydrogen leakage amount, even under the condition that the leaked hydrogen is fully diffused, the concentration detected by the hydrogen sensor will be affected by external conditions such as the size of the detection space, the specific environment of the detection space, and the size of the vehicle: it increases as the internal size of the closed space decreases and the vehicle size increases; if there are complex structures blocking near the installation position of the hydrogen sensor, it may also cause local hydrogen accumulation and high readings, and these factors all increase the uncertainty of the detection method and poor repeatability. Summary of the Invention

[0005] The present invention aims to provide a hydrogen leakage detection system and method for a hydrogen fuel vehicle with a mixing device. By arranging mixing blowers in the horizontal and vertical directions, the uniformity of the distribution of leaked hydrogen in the enclosed space is improved; an adjusting airbag is set to adjust its volume in the enclosed space to keep the air pressure in the enclosed space stable; hydrogen sensors arranged at different positions in the enclosed space are read respectively, and after obtaining the average concentration, it is multiplied by the difference between the internal volume of the enclosed space and the volume of the vehicle and the hydrogen density corrected to the test conditions to obtain the hydrogen leakage mass. This is to solve the problems of inaccurate detection results and poor repeatability in the prior art for detecting the hydrogen leakage amount of hydrogen fuel vehicles based on concentration.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A hydrogen leakage detection system for a hydrogen fuel vehicle with a mixing device, including a heat preservation cabin body for constructing an enclosed space. The heat preservation cabin body is connected with an intake blower, a hydrogen concentration sensor, a sunlight simulation system, a vertical mixing blower, an adjusting airbag and a horizontal mixing blower; the intake blower is equipped with a filtering device, and a ventilation valve for controlling the entry and exit of gas is connected between the intake blower and the heat preservation cabin body; the hydrogen concentration sensor, the sunlight simulation system and the vertical mixing blower are arranged at the top of the enclosed space; the hydrogen concentration sensor is used to detect the hydrogen concentration in the enclosed space; the sunlight simulation system is used to simulate the lighting condition when the vehicle is parked outdoors; the horizontal mixing blower is arranged on the side wall of the enclosed space, and the vertical mixing blower and the horizontal mixing blower are used to disturb the gas in the enclosed space to make the leaked hydrogen and air mix evenly; the adjusting airbag is used to adjust its volume in the enclosed space to keep the air pressure in the enclosed space stable; the heat preservation cabin body is also rotatably connected with a gate for opening or closing the enclosed space.

[0008] Further, the heat preservation cabin body is also connected with an inflatable sealing ring for sealing the gap at the gate where the vehicle enters and exits; when the vehicle needs to enter and exit, the inflatable sealing ring is not inflated inside to facilitate the opening and closing of the gate; when the vehicle enters the enclosed space and the internal purging is completed, the inflatable sealing ring is inflated inside to prevent the gas in the enclosed space from leaking to the external environment.

[0009] Further, the heat preservation cabin body includes a temperature control and a heat exchanger. The inside of the heat preservation cabin body is provided with heat exchange pipes with water as the working medium, so that the temperature of the body of the heat preservation cabin body and the enclosed space is controlled within the allowable error range of the test temperature; the inside of the heat preservation cabin body is made of polished aluminum plate or stainless steel plate on the surface to reduce the adsorption of hydrogen on the inner surface of the enclosed space.

[0010] Further, the filtering device is a HEPA high-efficiency particulate filter element to remove particulate matter in the purging gas and prevent the accumulation of particulate matter at the ventilation valve.

[0011] Further, the reading of the hydrogen concentration sensor is in volume fraction; there are eight hydrogen concentration sensors, and the eight hydrogen concentration sensors are respectively located at 10%, 40%, 60%, and 90% in the length direction and at 1 / 3 and 2 / 3 in the width direction at the top of the enclosed space.

[0012] Further, the fans of the vertical mixing fan and the horizontal mixing fan are both driven by a pair of magnets of a motor to keep them rotating at a low speed during the test.

[0013] Further, the adjusting airbag is made of Teflon material, and its inflatable tube is connected to an air pump; when the air pressure in the enclosed space rises due to temperature increase, the air pump pumps air out of the outside of the adjusting airbag to reduce its volume; when the air pressure in the enclosed space decreases due to temperature decrease, the air pump inflates the inside of the adjusting airbag to increase its volume, so as to keep the air pressure in the enclosed space stable.

[0014] A method for detecting hydrogen leakage using the above hydrogen fuel vehicle hydrogen leakage detection system with a mixing device includes the following steps:

[0015] S1. Open the gate, the vehicle enters the enclosed space constructed by the thermal insulation cabin body, and then close the gate;

[0016] S2. Open the ventilation valve, start the intake fan with a filtering device to purge the air in the enclosed space; after purging, close the intake fan and the ventilation valve, and inflate the inside of the inflatable seal to make it expand and fill the gap between the gate and the thermal insulation cabin body to prevent the gas in the enclosed space from leaking to the external environment from here;

[0017] S3. Start the heat exchanger and the sunlight simulation system in the thermal insulation cabin body to adjust the temperature in the enclosed space within the allowable error range of the test temperature; start the air pump to adjust the volume of the adjusting airbag and adjust the pressure in the enclosed space to the standard atmospheric pressure;

[0018] S4. The vehicle is left stationary in the enclosed space for more than 12 h and then the leakage test is started;

[0019] S5. After the leakage test starts, start the vertical mixing fan and the horizontal mixing fan, and both keep rotating at a low speed until the leakage test ends;

[0020] S6. After the vehicle has been left stationary in the enclosed space for the time required for the test, simultaneously read the readings of the eight hydrogen concentration sensors arranged at the top of the enclosed space and calculate the average hydrogen concentration;

[0021] S7. Calculate the hydrogen leakage amount based on the hydrogen leakage mass quantification method; the specific calculation formula is as follows:

[0022]

[0023] In the formula, m leak is the hydrogen leakage mass in the enclosed space, in g, ρ H2 is the hydrogen density corrected to the test temperature condition, in g / cm 3 , V chamber and sub-V vehicle are the internal volume of the enclosed space and the volume of the vehicle respectively, in m 3 , is the average value of the readings of eight hydrogen concentration sensors, in 10 -6 .

[0024] The principle and beneficial effects of the technical solution are as follows:

[0025] In the present invention, mixing fans are arranged both horizontally and vertically in the thermal insulation cabin to make the distribution uniformity of the leaked hydrogen in the enclosed space; an adjusting airbag is set to adjust its volume in the enclosed space to keep the air pressure in the enclosed space stable; the hydrogen leakage amount is calculated based on the hydrogen leakage mass quantification method. The hydrogen sensors arranged at different positions in the enclosed space are read respectively, and after obtaining the average concentration, it is multiplied by the difference between the internal volume of the enclosed space and the volume of the vehicle, and the hydrogen density corrected to the test conditions to obtain the hydrogen leakage mass. The obtained hydrogen leakage amount result data is accurate and has good repeatability. Brief Description of the Drawings

[0026] Figure 1 This is a schematic structural diagram of the present invention for measuring hydrogen leakage by placing a vehicle in a hydrogen leakage detection system of a hydrogen fuel vehicle with a mixing device;

[0027] The names of the corresponding marks in the drawings are:

[0028] Intake fan 1, ventilation valve 2, thermal insulation cabin 3, inflatable seal 4, gate 5, hydrogen concentration sensor 6, sunlight simulation system 7, vertical mixing fan 8, adjusting airbag 9, horizontal mixing fan 10, vehicle 11. Detailed Embodiments

[0029] The present invention will be further described in detail below in conjunction with the drawings and embodiments:

[0030] As Figure 1As shown in the figure, a hydrogen leakage detection system for a hydrogen fuel vehicle with a mixing device includes a heat-insulating cabin 3 for constructing a closed space. The heat-insulating cabin 3 includes a temperature control and heat exchanger. Inside the heat-insulating cabin 3, there are heat exchange pipes with water as the working medium, so that the temperature of the body of the heat-insulating cabin 3 and the closed space is controlled within the allowable error range of the test temperature. The inside of the heat-insulating cabin 3 is made of polished aluminum plate or stainless steel plate to reduce the adsorption of hydrogen on the inner surface of the closed space. The heat-insulating cabin 3 is connected with an intake fan 1, a hydrogen concentration sensor 6, a sunlight simulation system 7, a vertical mixing fan 8, an adjusting airbag 9, and a horizontal mixing fan 10. The intake fan 1 and the horizontal mixing fan 10 are arranged on the left side wall of the closed space. The intake fan 1 is equipped with a filtering device. A ventilation valve 2 for controlling the entry and exit of gas is connected between the intake fan 1 and the heat-insulating cabin 3. The filtering device is a HEPA high-efficiency particulate filter element to remove particulate matter in the purge gas and prevent particulate matter from accumulating at the ventilation valve 2. The hydrogen concentration sensor 6, the sunlight simulation system 7, and the vertical mixing fan 8 are arranged on the top of the closed space. The reading of the hydrogen concentration sensor 6 is the volume fraction. There are eight hydrogen concentration sensors 6, which are respectively located at 10%, 40%, 60%, and 90% in the length direction and at 1 / 3 and 2 / 3 in the width direction on the top of the closed space to detect the hydrogen concentration in the closed space. The sunlight simulation system 7 is used to simulate the lighting conditions when the vehicle 11 is parked outdoors. The fans of the vertical mixing fan 8 and the horizontal mixing fan 10 are driven by a pair of magnets of the motor, so that they rotate at a low speed during the test to disturb the gas in the closed space and make the leaked hydrogen and air mix evenly. The adjusting airbag 9 is made of Teflon material, and its charging pipe is connected to an air pump. When the air pressure in the closed space rises due to temperature increase, the air pump pumps air out of the outside of the adjusting airbag 9 to reduce its volume. When the air pressure in the closed space drops due to temperature decrease, the air pump inflates the inside of the adjusting airbag 9 to increase its volume to keep the air pressure in the closed space stable. The heat-insulating cabin 3 is rotatably connected with a gate 5 for opening or closing the closed space. The heat-insulating cabin 3 is also connected with an inflatable sealing ring 4 for sealing the gap where the vehicle 11 enters and exits the gate 5. When the vehicle 11 needs to enter and exit, the inflatable sealing ring 4 is not inflated to facilitate the opening and closing of the gate 5. When the vehicle 11 enters the closed space and the internal purge is completed, the inflatable sealing ring 4 is inflated to prevent the gas in the closed space from leaking to the external environment.

[0031] A method for detecting hydrogen leakage using the above hydrogen leakage detection system for a hydrogen fuel vehicle with a mixing device includes the following steps:

[0032] S1. Open the gate 5, the vehicle 11 enters the closed space constructed by the heat-insulating cabin 3, and then close the gate 5;

[0033] S2. Open the ventilation valve 2, start the intake fan 1 with a filtering device, and purge the air in the enclosed space. After purging, close the intake fan 1 and the ventilation valve 2, and inflate the inside of the inflatable seal 4 to make it expand and fill the gap between the gate 5 and the insulation cabin 3, so as to prevent the gas in the enclosed space from leaking to the external environment from here.

[0034] S3. Start the heat exchanger and the sunlight simulation system 7 in the insulation cabin 3 to adjust the temperature in the enclosed space within the allowable error range of the test temperature. Start the air pump to adjust the volume of the adjustment airbag 9 and adjust the pressure in the enclosed space to the standard atmospheric pressure.

[0035] S4. The vehicle 11 is stationary in the enclosed space for more than 12 h, and the leakage test is started.

[0036] S5. After the leakage test starts, start the vertical mixing fan 8 and the horizontal mixing fan 10, and both keep rotating at a low speed until the leakage test ends.

[0037] S6. After the stationary time of the vehicle 11 in the enclosed space reaches the test requirements, read the readings of the eight hydrogen concentration sensors 6 arranged on the top of the enclosed space at the same time, and calculate the average hydrogen concentration.

[0038] S7. Calculate the hydrogen leakage amount based on the hydrogen leakage mass quantification method. The specific calculation formula is as follows:

[0039]

[0040] In the formula, m leak is the hydrogen leakage mass in the enclosed space in g, ρH2 is the hydrogen density corrected to the test temperature condition in g / cm 3 , V chamber and sub-V vehicle are the internal volume of the enclosed space and the volume of the vehicle in m 3 , is the average value of the readings of the eight hydrogen concentration sensors in 10 -6 .

[0041] The above are only the embodiments of the present invention. Specific technical solutions or common knowledge such as characteristics well known in the solution are not described in detail here. It should be noted that for those skilled in the art, without departing from the technical solution of the present invention, several deformations and improvements can still be made, and these should also be regarded as the protection scope of the present invention, which will not affect the implementation effect of the present invention and the practicability of the patent. The protection scope required by this application should be subject to the content of its claims, and the specific implementation manners described in the specification can be used to explain the content of the claims.

Claims

1. Hydrogen fuel vehicle hydrogen leakage detection system with a mixing device, characterized in that: It includes a thermal insulation cabin for constructing a closed space, and the thermal insulation cabin is connected with an intake fan, a hydrogen concentration sensor, a sunlight simulation system, a vertical mixing fan, an adjusting airbag and a horizontal mixing fan; the intake fan is equipped with a filtering device, and a ventilation valve for controlling the entry and exit of gas is connected between the intake fan and the thermal insulation cabin; the hydrogen concentration sensor, the sunlight simulation system and the vertical mixing fan are arranged at the top of the closed space; the hydrogen concentration sensor is used to detect the hydrogen concentration in the closed space; the sunlight simulation system is used to simulate the lighting conditions when the vehicle is parked outdoors; the horizontal mixing fan is arranged on the side wall of the closed space, and the vertical mixing fan and the horizontal mixing fan are used to disturb the gas in the closed space to make the leaked hydrogen and air evenly mixed; the adjusting airbag is used to adjust its volume in the closed space to keep the air pressure in the closed space stable; the thermal insulation cabin is also rotatably connected with a gate for opening or closing the closed space; The adjusting airbag is made of Teflon material, and its air charging pipe is connected with an air pump; when the air pressure in the closed space rises due to temperature rise, the air pump pumps air out of the outside of the adjusting airbag to reduce its volume; when the air pressure in the closed space drops due to temperature drop, the air pump inflates the inside of the adjusting airbag to increase its volume to keep the air pressure in the closed space stable.

2. The hydrogen leakage detection system for a hydrogen fuel vehicle with a mixing device according to claim 1, characterized in that: The thermal insulation cabin is also connected with an inflatable sealing ring for sealing the gap where the vehicle enters and exits the gate; when the vehicle needs to enter and exit, the inside of the inflatable sealing ring is not inflated to facilitate the opening and closing of the gate; when the vehicle enters the closed space and the internal purging is completed, the inside of the inflatable sealing ring is inflated to prevent the gas in the closed space from leaking to the external environment.

3. The hydrogen leakage detection system for a hydrogen fuel vehicle with a mixing device according to claim 2, characterized in that: The thermal insulation cabin includes a temperature control and a heat exchanger. The inside of the thermal insulation cabin is provided with heat exchange pipes using water as the working medium, so that the temperature of the body of the thermal insulation cabin and the closed space is controlled within the allowable error range of the test temperature; the inside of the thermal insulation cabin is made of polished aluminum plate or stainless steel plate to reduce the adsorption of hydrogen on the inner surface of the closed space.

4. The hydrogen leakage detection system for a hydrogen fuel vehicle with a mixing device according to claim 3, characterized in that: The filtering device is a HEPA high-efficiency particulate filter element to remove particulate matter in the purging gas and prevent particulate matter from accumulating at the ventilation valve.

5. The hydrogen leakage detection system for a hydrogen fuel vehicle with a mixing device according to claim 4, characterized in that: The reading of the hydrogen concentration sensor is the volume fraction; there are eight hydrogen concentration sensors, and the eight hydrogen concentration sensors are respectively located at 10%, 40%, 60% and 90% in the length direction and 1 / 3 and 2 / 3 in the width direction at the top of the closed space.

6. The hydrogen leakage detection system for a hydrogen fuel vehicle with a mixing device according to claim 5, characterized in that: The fans of the vertical mixing fan and the horizontal mixing fan are both driven by a pair of magnets by a motor to keep them rotating at a low speed during the test.

7. A method for detecting hydrogen leakage using the hydrogen fuel vehicle hydrogen leakage detection system with a mixing device according to claim 6, characterized in that, It includes the following steps: S1. Open the gate, the vehicle enters the closed space constructed by the thermal insulation cabin, and then close the gate; S2. Open the ventilation valve, start the intake fan with a filtering device, and purge the air in the enclosed space. After purging, close the intake fan and the ventilation valve, and inflate the inflatable seal ring to make it expand and fill the gap between the gate and the thermal insulation cabin body to prevent the gas in the enclosed space from leaking to the external environment through this place. S3. Start the heat exchanger and the sunlight simulation system in the thermal insulation cabin body to adjust the temperature in the enclosed space within the allowable error range of the test temperature. Start the air pump to adjust the volume of the regulating airbag and adjust the pressure in the enclosed space to the standard atmospheric pressure. S4. The vehicle is left stationary in the enclosed space for more than 12 h, and the leakage test is started. S5. After the leakage test starts, start the vertical mixing fan and the horizontal mixing fan, and both keep rotating at a low speed until the leakage test ends. S6. After the vehicle has been left stationary in the enclosed space for the time required for the test, simultaneously read the readings of the eight hydrogen concentration sensors arranged at the top of the enclosed space, and calculate the average hydrogen concentration. S7. Calculate the hydrogen leakage amount based on the hydrogen leakage mass quantification method. The specific calculation formula is as follows: ； Where m leak is the mass of hydrogen leakage in the enclosed space, in g, is the hydrogen density corrected to the test temperature condition, in g / cm 3 , V chamber and V vehicle are the internal volume of the enclosed space and the volume of the vehicle, in m 3 , is the average value of the readings of eight hydrogen concentration sensors, in 10 -6 .

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