A fuel cell vehicle hydrogen emission concentration tester

Abstract

The present invention relates to a fuel cell vehicle hydrogen emission concentration tester, comprising an exhaust gas sampler for collecting exhaust gas from a fuel cell vehicle; a dryer for drying the collected exhaust gas; a sampling pump (4) for introducing the dried exhaust gas into a thermal conductivity cell (5); and a thermal conductivity cell (5) for detecting the hydrogen concentration in the exhaust gas. The exhaust gas sampler is connected to the thermal conductivity cell (5) through the dryer and the sampling pump (4) in sequence. Compared with the prior art, the present invention can detect hydrogen concentration in a wide range and has high detection accuracy.

Description

Technical Field

[0001] The invention relates to the technical field of fuel cell systems, and in particular to a hydrogen emission concentration tester for a fuel cell vehicle. Background Art

[0002] Fuel cell vehicles use flammable and explosive hydrogen as fuel. The hydrogen at the anode and the air at the cathode are separated by a proton exchange membrane, and electrochemical reactions occur under the action of the anode catalyst and the cathode catalyst, respectively, to generate current. However, in order to remove the nitrogen that penetrates from the cathode to the anode and the liquid water produced by the reaction, the hydrogen at the anode must be discharged once every certain period of time. When exhausting, the gas and water discharged from the anode are mixed with the air and water discharged from the cathode and discharged from the stack through the tail exhaust pipe.

[0003] While being clean and environmentally friendly, the hydrogen concentration in the tail gas of fuel cell vehicles is somewhat dangerous. Once the hydrogen concentration exceeds the flammable limit, it is very likely to cause ignition, detonation, combustion, and even explosion in a closed environment. Currently, the anode tail gas emissions of fuel cell vehicles on the market are intermittent to improve the economy of fuel. Therefore, the tail gas concentration of hydrogen is intermittent and irregular, and fluctuates over time. It is possible that the hydrogen concentration exceeds the limit at a certain time, posing a danger to fuel cell vehicles, passengers, people outside the vehicle, and facilities.

[0004] Accurate monitoring of hydrogen emission concentration involves the safety of the vehicle, passengers, personnel outside the vehicle and facilities. At present, handheld combustible gas alarms or hydrogen concentration sensors are usually used for detection. This method has the disadvantages of unstable sampling points, inaccurate concentrations, narrow measurable concentration range and discontinuous data. Therefore, there is an urgent need for an instrument that can detect hydrogen concentration in real time to monitor the hydrogen tail emission concentration of fuel cell vehicles during the entire operation process, so as to provide a basis for the development of vehicle tail emission control strategies and vehicle driving safety. Summary of the invention

[0005] The purpose of the present invention is to provide a fuel cell vehicle hydrogen emission concentration tester in order to overcome the defects of the prior art.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] A fuel cell vehicle hydrogen emission concentration tester, the tester comprising:

[0008] Exhaust sampler: collects exhaust gas from fuel cell vehicles;

[0009] Dryer: Dry the collected exhaust gas;

[0010] Sampling pump: introduces the dried exhaust gas into the thermal conductivity cell;

[0011] Thermal conductivity cell: detects hydrogen concentration in exhaust gas;

[0012] The tail gas sampler is connected to the thermal conductivity cell via a dryer and a sampling pump in sequence.

[0013] Preferably, the exhaust gas sampler comprises an exhaust gas sampling port and a sampling tube, the exhaust gas sampling port is a hose sampling port, and the hose sampling port is connected to the dryer through the sampling tube.

[0014] Preferably, a filter element is provided at the exhaust gas inlet end of the hose sampling port.

[0015] Preferably, a rotor flowmeter for controlling the flow rate of the exhaust gas introduced into the thermal conductivity cell is provided between the dryer and the sampling pump.

[0016] Preferably, the dryer comprises a dryer which uses high-temperature gas discharged from a thermal conductivity cell to dry the collected tail gas.

[0017] Preferably, the dryer comprises an exhaust gas inlet cavity and a thermal conductivity cell exhaust cavity, one end of the exhaust gas inlet cavity is connected to an exhaust gas collector, the other end of the exhaust gas inlet cavity is connected to an air inlet of the thermal conductivity cell through a sampling pump, the exhaust port of the thermal conductivity cell is connected to the thermal conductivity cell exhaust cavity, the thermal conductivity cell exhaust cavity is provided with an exhaust pipe, and the exhaust gas inlet cavity and the thermal conductivity cell exhaust cavity are isolated by a gas-blocking and moisture-permeable membrane.

[0018] Preferably, the gas-barrier and moisture-permeable membrane has a shape of a plate or a tube.

[0019] Preferably, the gas-barrier and moisture-permeable membrane comprises a hollow fiber membrane, a nanofiltration membrane and a perfluorosulfonic acid membrane.

[0020] Preferably, the tester further comprises an industrial computer for temperature control and pressure monitoring of the thermal conductivity cell, and the industrial computer is connected to the thermal conductivity cell.

[0021] Preferably, the tester further comprises a communication interface for real-time collection of hydrogen concentration, and the communication interface is connected to the thermal conductivity cell.

[0022] Compared with the prior art, the present invention has the following advantages:

[0023] (1) The present invention uses a thermal conductivity cell as a hydrogen concentration detector. Compared with other combustible gas alarms and electrochemical sensors, the detector has the advantages of good linear response between concentration and resistance value of thermistor, wide linear range and good reproducibility. At the same time, a dryer is used to dry the wet automobile exhaust gas entering the thermal conductivity cell to protect the dryness in the thermal conductivity cell, thereby eliminating the influence of humidity on the thermal conductivity system and ensuring the accuracy of measurement;

[0024] (2) The hose sampling port of the exhaust sampler of the present invention is provided with a filter element to prevent the inhalation of liquid water, large particles, leaves, pollen and other solid impurities, etc., effectively preventing the inhalation of impurities from affecting the stable operation of the entire tester and ensuring its reliability;

[0025] (3) The dryer of the present invention is configured to use the high-temperature gas discharged from the thermal conductivity cell to dry the collected exhaust gas. The specific working method is as follows: the high-temperature (50°C) dry hydrogen-containing gas discharged from the thermal conductivity cell absorbs moisture and dries the moist hydrogen-containing automobile exhaust gas that even contains liquid water. On the one hand, the high-temperature gas discharged from the thermal conductivity cell is reused; on the other hand, the dryness of the automobile exhaust gas entering the thermal conductivity cell is ensured, and the influence of humidity on the thermal conductivity system is eliminated.

[0026] (4) The gas barrier and moisture permeable membrane of the present invention has a plate type and a tube type. Correspondingly, the tail gas inlet cavity and the heat conduction pool exhaust cavity will be adaptively changed, the structure is simple, and the manufacturing cost is low;

[0027] (5) The present invention uses an industrial computer to control the temperature of the thermal conductivity cell and monitor the pressure to ensure accurate and stable measurement of hydrogen concentration. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a schematic diagram of the overall structure of a hydrogen emission concentration tester for a fuel cell vehicle in Example 1 of the present invention;

[0029] Figure 2 This is a schematic diagram of the internal structure of the hydrogen emission concentration tester for a fuel cell vehicle in Example 1 of the present invention;

[0030] Figure 3 This is a schematic diagram of the structure of a dryer assembly of a fuel cell vehicle hydrogen emission concentration tester in Example 1 of the present invention;

[0031] Figure 4 The actual test results of the hydrogen emission concentration tester for a fuel cell vehicle in Example 1 of the present invention;

[0032] Figure 5 This is a schematic diagram of the internal structure of a fuel cell vehicle hydrogen emission concentration tester in Example 2 of the present invention;

[0033] Figure 6 This is a schematic diagram of the structure of the dryer assembly of the hydrogen emission concentration tester for a fuel cell vehicle in Example 2 of the present invention.

[0034] In the figure, 1 is the exhaust gas sampling port, 2 is the sampling tube, 3 is the tubular dryer, 4 is the sampling pump, 5 is the thermal conductivity cell, 6 is the industrial computer, 7 is the communication interface, 8 is the AC-DC converter, 9 is the data processing and DC power supply module, 10 is the rotor flowmeter, 11 is the exhaust port, 12 is the exhaust gas intake connector, 13 is the outer tube, 14 is the inner tube, 15 is the thermal conductivity cell exhaust pipe, 16 is the thermal conductivity cell intake pipe, 17 is the plate dryer, 18 is the diaphragm, 19 is the upper cavity, 20 is the lower cavity, and 21 is the fastening screw. DETAILED DESCRIPTION

[0035] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. Note that the following embodiments are merely illustrative in nature, and the present invention is not intended to limit its applicable objects or uses, and the present invention is not limited to the following embodiments.

[0036] Example 1

[0037] like Figures 1 to 3 As shown, a fuel cell vehicle hydrogen emission concentration tester, the tester comprises:

[0038] Exhaust sampler: collects exhaust gas from fuel cell vehicles;

[0039] Dryer: Dry the collected exhaust gas;

[0040] Sampling pump 4: introduces the dried tail gas into the thermal conductivity cell 5;

[0041] Thermal conductivity cell 5: detects the hydrogen concentration in the tail gas. In this embodiment, the thermal conductivity cell 5 uses a commercially available module, and the measurement range of the hydrogen concentration must reach 0.01 to 100% VOL, with an accuracy of ±1% FS.

[0042] The tail gas sampler is connected to the thermal conductivity cell 5 via a dryer and a sampling pump 4 in sequence. A rotor flowmeter 10 for controlling the flow rate of the tail gas introduced into the thermal conductivity cell 5 is provided between the dryer and the sampling pump 4 .

[0043] In addition, the tester also includes an industrial computer 6 for temperature control and pressure monitoring of the thermal conductivity cell 5, a communication interface 7 for real-time collection of hydrogen concentration, and components for power supply and data processing. The industrial computer 6 and the communication interface 7 are both connected to the thermal conductivity cell 5. The power supply and data processing components include an AC / DC converter 8 and a data processing and DC power supply module 9. The AC / DC converter 8 is used to generate DC power. The data processing and DC power supply module 9 connects the sampling pump 4, the thermal conductivity cell 5, the industrial computer 6 and the communication interface 7 and supplies power to them respectively. The industrial computer 6 is used to turn on and off the thermal conductivity cell 5, control the temperature and monitor the pressure to ensure accurate and stable measurement of hydrogen concentration. The communication interface 7 can be an interface such as RS232, RS485, RS422 or RJ45. It is connected to a computer or a printer through the communication interface 7 to realize real-time collection and recording of hydrogen concentration.

[0044] The exhaust gas sampler comprises an exhaust gas sampling port 1 and a sampling tube 2. The exhaust gas sampling port 1 is a hose sampling port, which is connected to a dryer through the sampling tube 2. A filter element with a certain porosity is provided at the exhaust gas inlet end of the hose sampling port.

[0045] The dryer in the present invention uses the high-temperature gas discharged from the thermal conductivity cell 5 to dry the collected exhaust gas. Specifically, the dryer includes an exhaust gas inlet chamber and a thermal conductivity cell exhaust chamber. One end of the exhaust gas inlet chamber is connected to the exhaust gas collector, and the other end of the exhaust gas inlet chamber is connected to the air inlet of the thermal conductivity cell 5 through the sampling pump 4. The exhaust port of the thermal conductivity cell 5 is connected to the thermal conductivity cell exhaust chamber. The thermal conductivity cell exhaust chamber is provided with an exhaust pipe, and the exhaust gas inlet chamber and the thermal conductivity cell exhaust chamber are separated by an air-blocking and moisture-permeable membrane. The shape of the air-blocking and moisture-permeable membrane includes a plate type or a tube type. Correspondingly, the specific forms of the exhaust gas inlet chamber and the thermal conductivity cell exhaust chamber will undergo adaptive changes. In this embodiment, the air-blocking and moisture-permeable membrane is set to a tube type, and the corresponding exhaust gas inlet chamber and the thermal conductivity cell exhaust chamber are also designed to be tubular cavities, as shown in the following example. Figure 2 and 3 As shown, in this embodiment, two mutually nested outer tubes 13 and inner tubes 14 are provided, the inner cavity of the inner tube 14 constitutes the tail gas intake cavity, and the cavity between the inner tube 14 and the outer tube 13 constitutes the heat conduction pool exhaust cavity. At this time, the inner tube 14 is a tubular gas-blocking and moisture-permeable membrane, thereby forming a tubular dryer 3. The gas-blocking and moisture-permeable membrane includes a hollow fiber membrane, a nanofiltration membrane and a perfluorosulfonic acid membrane, which can be selected as needed. On this basis, an exhaust gas intake connector 12 is provided at one end of the inner tube 14, and the exhaust gas intake connector 12 is used to connect the sampling tube 2 of the exhaust gas sampler. A thermal conductivity cell intake pipe 16 is provided at the other end of the inner tube 14, and the thermal conductivity cell intake pipe 16 is connected to the thermal conductivity cell 5 through the rotor flowmeter 10 and the sampling pump 4 in sequence; a thermal conductivity cell exhaust pipe 15 is provided at one end of the outer tube 13, and the thermal conductivity cell exhaust pipe 15 is connected to the exhaust port of the thermal conductivity cell 5. An exhaust port 11 is provided at the other end of the outer tube 13. The hot air discharged from the thermal conductivity cell 5 is discharged through the thermal conductivity cell exhaust pipe 15, and the hot gas flows through the outer tube 13 to the exhaust port 11 for complete discharge.

[0046] The specific working principle of the fuel cell vehicle hydrogen emission concentration tester of this embodiment is as follows: under the suction force of the sampling pump 4 and the flow rate is controlled by the rotor flowmeter 10, a certain volume flow of fuel cell vehicle exhaust gas is sampled through the exhaust sampling port 1, and then introduced into the thermal conductivity cell 5 after being dried by the dryer. The thermal conductivity cell 5 is kept at a constant 50°C by electric heating to eliminate the influence of temperature on the thermal conductivity system. The specific process of drying the automobile exhaust gas introduced into the thermal conductivity cell 5 is as follows: the fuel cell vehicle exhaust gas with a high water vapor content passes through the exhaust gas intake joint 12 into the inner tube 14, and the dry hot air coming out of the thermal conductivity cell 5 enters the outer tube 13 through the thermal conductivity cell exhaust pipe 15. Driven by the water vapor concentration difference, the moisture in the water-containing automobile exhaust gas will pass through the wall of the inner tube 14 into the outer tube 13, thereby achieving the effect of dehumidification. As a result, the dryness in the thermal conductivity cell 5 is effectively guaranteed without affecting its resistance value. The hydrogen emission concentration tester described in the present invention uses a thermal conductivity cell 5 as a hydrogen concentration detector. Compared with other combustible gas alarms and electrochemical sensors, this detector has the advantages of good linear response between concentration and thermistor resistance value, wide linear range and good reproducibility. It can monitor the tail exhaust hydrogen concentration of fuel cell vehicles in real time during the entire process of starting, idling, normal driving and stopping.

[0047] In this embodiment, air is used as the carrier gas and standard gas is used to investigate the actual test effect of the tester. The experimental results are as follows: Figure 4 shown. Figure 4 In the example, the instrument is turned on for 80 seconds to complete preheating; the sampling pump 4 starts to start, and at this time, normal air enters the thermal conductivity cell 5 as a carrier gas, and the electrical information of the thermal conductivity cell 5 at this time is used as the zero point; 10 minutes later, 100ppm (volume ratio) of standard gas is introduced, and the standard gas uses air as the background gas; after the standard gas is introduced, the instrument responds almost instantly and reaches a stable value after 10 seconds; at 1020 seconds, 20% of hydrogen standard gas, which is much higher than the ignition concentration, is introduced, and the standard gas uses nitrogen as the background gas. Similarly, it can be seen that the instrument has a fast response and basically reaches a stable reading after 120 seconds.

[0048] Depend on Figure 4 It can be seen that the instrument of the present invention can produce a rapid response to hydrogen-containing gas. The difference in the concentration range from 100ppm to 20% has reached 4 orders of magnitude; such a large measurement range has exceeded the existing and most commonly used hydrogen concentration tester based on electrochemical sensors. In addition, whether air or nitrogen is used as the carrier gas, the impact of the equipment is very fast, which is enough to reflect the irregular and fluctuating change characteristics of the hydrogen concentration of the fuel cell during the variable working condition.

[0049] Example 2

[0050] The difference between the fuel cell vehicle hydrogen emission concentration tester of this embodiment and the embodiment 1 is that the gas barrier and moisture permeable membrane of this embodiment is set as a plate, and the corresponding exhaust gas intake cavity and thermal conductivity cell exhaust cavity are square cavities. Figure 5 and 6 As shown, this embodiment is provided with an upper cavity 19 and a lower cavity 20 which are sealed and connected, and the upper cavity 19 and the lower cavity 20 are sealed and connected by fastening screws 21, and a plate-type diaphragm 18 is provided between the upper cavity 19 and the lower cavity 20, thereby forming a plate-type dryer 17, and in this embodiment, the upper cavity 19 is the exhaust cavity of the heat conduction cell, and the lower cavity 20 is the exhaust inlet cavity, and the diaphragm 18 is a gas-blocking and moisture-permeable membrane. On this basis, an exhaust gas inlet connector 12 is provided at one end of the upper and lower cavities 20, and the exhaust gas inlet connector 12 is used to connect the sampling tube 2 of the exhaust gas sampler. A thermal conductivity cell inlet pipe 16 is provided at the other end of the lower cavity 20, and the thermal conductivity cell inlet pipe 16 is connected to the thermal conductivity cell 5 through the rotor flowmeter 10 and the sampling pump 4 in turn; a thermal conductivity cell exhaust pipe 15 is provided at one end of the upper cavity 19, and the thermal conductivity cell exhaust pipe 15 is connected to the exhaust port of the thermal conductivity cell 5. An exhaust port 11 is provided at the other end of the upper cavity 19, and the hot gas discharged from the thermal conductivity cell 5 is discharged through the thermal conductivity cell exhaust pipe 15, and the hot gas flows through the upper cavity 19 to the exhaust port 11 for complete discharge. The difference from Example 1 is that the dryer in Example 1 is a tubular dryer 3, while the dryer in this embodiment is a plate dryer 17, and the rest is the same as Example 1. The tester of this embodiment is used for actual test and investigation, and its test effect is basically the same as that of Example 1. The instrument can produce a rapid response to hydrogen-containing gas and has a large measurement range.

[0051] The above embodiments are merely examples and do not limit the scope of the present invention. These embodiments can also be implemented in various other ways, and various omissions, substitutions, and changes can be made without departing from the technical concept of the present invention.

Claims

1. A fuel cell vehicle hydrogen emission concentration tester, characterized in that: The tester includes: Exhaust sampler: collects exhaust gas from fuel cell vehicles; Dryer: Dry the collected exhaust gas; Sampling pump (4): to guide the dried tail gas into the thermal conductivity cell (5); Thermal conductivity cell (5): detects the hydrogen concentration in the exhaust gas; The exhaust gas sampler is connected to the thermal conductivity cell (5) via a dryer and a sampling pump (4) in sequence; The exhaust gas sampler comprises an exhaust gas sampling port (1) and a sampling tube (2), wherein the exhaust gas sampling port (1) is a hose sampling port, and the hose sampling port is connected to the dryer through the sampling tube (2); The dryer comprises a dryer which uses high-temperature gas discharged from a heat conduction cell (5) to dry the collected tail gas; The dryer comprises two mutually nested outer tubes (13) and an inner tube (14); the inner cavity of the inner tube (14) constitutes an exhaust gas inlet cavity; the cavity between the inner tube (14) and the outer tube (13) constitutes a heat conduction pool exhaust cavity; the inner tube (14) is a tubular gas-blocking and moisture-permeable membrane; one end of the inner tube (14) is provided with an exhaust gas inlet connector (12), the exhaust gas inlet connector (12) being used to connect to a sampling tube (2) of an exhaust gas sampler; the other end of the inner tube (14) is provided with a heat conduction pool inlet connector (12). An air pipe (16) is provided, wherein the heat conduction cell air inlet pipe (16) is connected to the heat conduction cell (5) through a sampling pump (4); a heat conduction cell exhaust pipe (15) is provided at one end of the outer pipe (13), wherein the heat conduction cell exhaust pipe (15) is connected to an exhaust port of the heat conduction cell (5); an exhaust port (11) is provided at the other end of the outer pipe (13); hot air discharged from the heat conduction cell (5) is discharged through the heat conduction cell exhaust pipe (15) 15, and the hot air flows through the outer pipe (13) to the exhaust port (11) for complete discharge.

2. A fuel cell vehicle hydrogen emission concentration tester, characterized in that: The tester includes: Exhaust sampler: collects exhaust gas from fuel cell vehicles; Dryer: Dry the collected exhaust gas; Sampling pump (4): to guide the dried tail gas into the thermal conductivity cell (5); Thermal conductivity cell (5): detects the hydrogen concentration in the exhaust gas; The exhaust gas sampler is connected to the thermal conductivity cell (5) via a dryer and a sampling pump (4) in sequence; The exhaust gas sampler comprises an exhaust gas sampling port (1) and a sampling tube (2), wherein the exhaust gas sampling port (1) is a hose sampling port, and the hose sampling port is connected to the dryer through the sampling tube (2); The dryer comprises a dryer which uses high-temperature gas discharged from a heat conduction cell (5) to dry the collected tail gas; The dryer comprises an upper cavity (19) and a lower cavity (20) which are sealed and connected. A plate-type diaphragm (18) is arranged between the upper cavity (19) and the lower cavity (20), thereby forming a plate-type dryer (17). The upper cavity (19) is a heat conduction cell exhaust cavity, and the lower cavity (20) is an exhaust gas intake cavity. The diaphragm (18) is a gas-blocking and moisture-permeable membrane. An exhaust gas intake connector (12) is arranged at one end of the lower cavity (20). The exhaust gas intake connector (12) is used to connect a sampling tube (2) of an exhaust gas sampler. A thermal conductivity cell air inlet pipe (16) is provided at the other end of the lower cavity (20), and the thermal conductivity cell air inlet pipe (16) is connected to the thermal conductivity cell (5) through a sampling pump (4); a thermal conductivity cell exhaust pipe (15) is provided at one end of the upper cavity (19), and the thermal conductivity cell exhaust pipe (15) is connected to an exhaust port of the thermal conductivity cell (5); an exhaust port (11) is provided at the other end of the upper cavity (19); hot air discharged from the thermal conductivity cell (5) is discharged through the thermal conductivity cell exhaust pipe (15), and the hot air flows through the upper cavity (19) to the exhaust port (11) for complete discharge.

3. A fuel cell vehicle hydrogen emission concentration tester according to claim 1 or 2, characterized in that: A filter element is arranged at the tail gas inlet end of the hose sampling port.

4. A fuel cell vehicle hydrogen emission concentration tester according to claim 1 or 2, characterized in that: A rotor flowmeter (10) for controlling the flow rate of tail gas introduced into the thermal conductivity cell (5) is provided between the dryer and the sampling pump (4).

5. A fuel cell vehicle hydrogen emission concentration tester according to claim 1 or 2, characterized in that: The gas-barrier and moisture-permeable membranes include hollow fiber membranes, nanofiltration membranes and perfluorosulfonic acid membranes.

6. A fuel cell vehicle hydrogen emission concentration tester according to claim 1 or 2, characterized in that: The tester also includes an industrial computer (6) for temperature control and pressure monitoring of the thermal conductivity cell (5), wherein the industrial computer (6) is connected to the thermal conductivity cell (5).

7. A fuel cell vehicle hydrogen emission concentration tester according to claim 1 or 2, characterized in that: The tester also includes a communication interface (7) for real-time collection of hydrogen concentration, and the communication interface (7) is connected to the thermal conductivity cell (5).

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