Nitrogen-oxygen sensor testing device

Abstract

The nitrogen-oxygen sensor testing device comprises a gas distribution device and a ventilation device, the gas distribution device comprises a nitrogen gas cylinder, an oxygen cylinder and a nitric oxide gas cylinder, and output pipelines of the nitrogen gas cylinder and the oxygen cylinder are both communicated with an A1 inlet of a first electromagnetic three-way valve; an output pipeline of the nitric oxide gas cylinder is communicated with an A2 outlet of the first electromagnetic three-way valve and a B2 inlet of the second electromagnetic three-way valve, an A3 outlet of the first electromagnetic three-way valve is communicated with a B1 inlet of the second electromagnetic three-way valve, a B3 outlet of the second electromagnetic three-way valve is communicated with the ventilation device, and a nitrogen and oxygen sensor to be detected is installed in the ventilation device. By controlling the communication state of the first electromagnetic three-way valve and the second electromagnetic three-way valve, the nitric oxide gas output pipeline can be switched on and switched off, and after the nitric oxide gas output pipeline is switched off, the nitric oxide gas remaining in the pipeline cannot enter the ventilation device to influence the purity of the test gas; and the accuracy of a test result is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of sensor testing, in particular to a nitrogen oxide sensor testing device. Background Technique

[0002] Nitrogen oxide sensors are mainly used to test the content of NO and N2 in the exhaust gas of diesel vehicles. After the production of nitrogen oxide sensors, they need to be tested. Testing on the vehicle is rather troublesome and not suitable for routine testing within the company.

[0003] When testing a nitrogen oxide sensor, first a test gas similar to the exhaust gas composition will be configured by a gas distribution device, and then the nitrogen oxide sensor will be tested using the test gas. Currently, the general gas distribution device includes a nitric oxide gas cylinder, a nitrogen gas cylinder, an oxygen gas cylinder, and a mixing chamber. The output pipelines of the nitric oxide gas cylinder, the nitrogen gas cylinder, and the oxygen gas cylinder are respectively connected to the mixing chamber. The nitrogen oxide sensor to be tested is installed in the mixing chamber to detect the mixed test gas.

[0004] However, the problem with the existing gas distribution device is that when the required test gas only contains nitrogen and oxygen, even if the valve of the nitric oxide gas cylinder is closed, the residual nitric oxide gas in its output pipeline will enter the mixing chamber, thus affecting the purity of the test gas and further affecting the test results of the nitrogen oxide sensor. Content of the Utility Model

[0005] The utility model provides a nitrogen oxide sensor testing device, which solves the problems existing in the existing gas distribution device. When the required test gas only contains nitrogen and oxygen, even if the valve of the nitric oxide gas cylinder is closed, the residual nitric oxide gas in its output pipeline will enter the mixing chamber, thus affecting the purity of the test gas and further affecting the test results of the nitrogen oxide sensor.

[0006] The technical solution of the utility model is realized as follows:

[0007] The utility model provides a nitrogen oxide sensor testing device, which includes a gas distribution device and a ventilation device. The gas distribution device includes a nitrogen gas cylinder, an oxygen gas cylinder, a nitric oxide gas cylinder, a first electromagnetic three-way valve, and a second electromagnetic three-way valve. Nitrogen flow meters, oxygen flow meters, and nitric oxide flow meters are respectively installed on the output pipelines of the nitrogen gas cylinder, the oxygen gas cylinder, and the nitric oxide gas cylinder. The output pipelines of the nitrogen gas cylinder and the oxygen gas cylinder are both connected to the A1 inlet of the first electromagnetic three-way valve. The output pipeline of the nitric oxide gas cylinder is respectively connected to the A2 outlet of the first electromagnetic three-way valve and the B2 inlet of the second electromagnetic three-way valve. The A3 outlet of the first electromagnetic three-way valve is connected to the B1 inlet of the second electromagnetic three-way valve. The B3 outlet of the second electromagnetic three-way valve is connected to the ventilation device, and the nitrogen oxide sensor to be tested is installed in the ventilation device.

[0008] By providing a first electromagnetic three-way valve and a second electromagnetic three-way valve, and controlling the connection states of the first electromagnetic three-way valve and the second electromagnetic three-way valve, the on-off of the output pipeline of nitric oxide gas can be achieved. After the output pipeline of nitric oxide gas is turned off, the residual nitric oxide gas in the pipeline will not enter the ventilation device to affect the purity of the test gas, thus improving the accuracy of the test results.

[0009] Specifically, the ventilation device includes a bottom plate. A hollow shaft is provided on the top surface of the bottom plate. A test cavity is arranged inside the hollow shaft. An air inlet interface communicating with the test cavity is provided on the top surface of the hollow shaft. The air inlet interface is used to communicate with the B3 outlet of the second electromagnetic three-way valve. A through hole communicating with the test cavity is formed on the bottom surface of the bottom plate. The through hole is used to install the probe of the nitrogen-oxygen sensor to be tested. The gas output by the gas distribution device is introduced into the test cavity through the air inlet interface for mixing, and the nitrogen-oxygen sensor to be tested is tested.

[0010] Further, the inner diameter of the through hole is smaller than the inner diameter of the test cavity. The bottom end face of the test cavity forms an annular step in the through hole for installing the probe of the nitrogen-oxygen sensor to be tested, which facilitates the installation of the nitrogen-oxygen sensor.

[0011] Preferably, a bushing is sleeved outside the hollow shaft. The inner diameter of the bushing matches the outer diameter of the hollow shaft. A buffer cavity is arranged inside the bushing. An air vent communicating with the buffer cavity is formed on the side wall of the hollow shaft. An air outlet communicating with the buffer cavity is formed on the side wall of the bushing. The air outlet is communicated with the air inlet interface of the adjacent ventilation device through a pipeline. By providing a buffer cavity inside the bushing, the gas in the test cavity can be introduced into the buffer cavity through the air vent, avoiding excessive pressure in the test cavity from affecting the sensor's signal acquisition. By providing air outlets on the side wall of the bushing, it is convenient to connect multiple ventilation devices in series to realize the synchronous testing of multiple nitrogen-oxygen sensors, greatly improving the testing efficiency.

[0012] Preferably, there are multiple air vents. The multiple air vents are evenly arranged circumferentially along the side wall of the hollow shaft. By providing multiple air vents, the influence of pressure differences in different directions on the sensor's testing can be avoided, making the pressures in different directions of the sensor the same.

[0013] Further, a first shaft shoulder is provided outside the hollow shaft. The outer diameter of the first shaft shoulder matches the inner diameter of the buffer cavity. The first shaft shoulder is inserted into the buffer cavity from the bottom end of the bushing. The bottom end face of the bushing abuts against the top surface of the bottom plate. By providing the first shaft shoulder, the installation and positioning of the bushing are facilitated.

[0014] Further, a second shoulder is provided on the outer side of the hollow shaft. The bottom surface of the second shoulder is adjacent to the top surface of the first shoulder. The outer diameter of the second shoulder is smaller than that of the first shoulder and larger than the inner diameter of the air inlet interface. The top surface of the second shoulder abuts against the top surface of the buffer chamber. The vent hole penetrates through the side wall of the second shoulder. By providing the second shoulder, on the one hand, the volume of the buffer chamber can be reduced, reducing the consumption of the test gas, and on the other hand, it is also convenient for the installation and sealing of the bushing.

[0015] Specifically, through holes are provided on the top surface of the bushing and the top surface of the bottom plate. The bushing and the bottom plate are connected by bolts. After the bolts pass through the mounting holes on the bushing and the bottom plate, they are locked by nuts, which is convenient for installation.

[0016] Further, a first annular groove is provided on the top surface of the bottom plate, and a second annular groove is provided on the top surface of the second shoulder. Sealing rings are provided in the first annular groove and the second annular groove. By providing the first annular groove and the second annular groove, it is convenient to install the sealing rings between the top surface of the bottom plate and the bottom surface of the bushing and between the top surface of the test cavity and the top surface of the second shoulder, which can prevent the leakage of the test gas.

[0017] Preferably, the first shoulder, the second shoulder, the hollow shaft and the bottom plate are integrally formed, and the structure is more firm. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0019] Figure 1 is a schematic diagram of the principle of the gas distribution device in the embodiment of the present invention;

[0020] Figure 2 is a front sectional view of the ventilation device in the embodiment of the present invention;

[0021] Figure 3 is a side sectional view of the ventilation device in the embodiment of the present invention;

[0022] Figure 4 is an exploded view of the ventilation device in the embodiment of the present invention;

[0023] In the figure: 1, nitrogen gas cylinder; 2, oxygen gas cylinder; 3, nitrogen monoxide gas cylinder; 4, first electromagnetic three-way valve; 5, second electromagnetic three-way valve; 6, nitrogen gas flowmeter; 7, oxygen gas flowmeter; 8, nitrogen monoxide flowmeter; 9, A1 inlet; 10, A2 outlet; 11, A3 outlet; 12, B1 inlet; 13, B2 inlet; 14, B3 outlet; 15, bottom plate; 16, hollow shaft; 17, test cavity; 18, air inlet interface; 19, through hole; 20, annular step; 21, bushing; 22, buffer cavity; 23, vent hole; 24, air outlet hole; 25, first shaft shoulder; 26, second shaft shoulder; 27, mounting hole; 28, first annular groove; 29, second annular groove. Detailed implementation manners

[0024] The technical solutions of the present utility model will be clearly and completely described below in conjunction with the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present utility model.

[0025] Referring to Figure 1 , the embodiments of the present utility model provide a nitrogen-oxygen sensor testing device, including a gas distribution device and a gas ventilation device. The gas distribution device includes a nitrogen gas cylinder 1, an oxygen gas cylinder 2, a nitrogen monoxide gas cylinder 3, a first electromagnetic three-way valve 4 and a second electromagnetic three-way valve 5. Nitrogen gas flowmeters 6, oxygen gas flowmeters 7 and nitrogen monoxide flowmeters 8 are respectively installed on the output pipelines of the nitrogen gas cylinder 1, the oxygen gas cylinder 2 and the nitrogen monoxide gas cylinder 3. The output pipelines of the nitrogen gas cylinder 1 and the oxygen gas cylinder 2 are both connected to the A1 inlet 9 of the first electromagnetic three-way valve 4. The output pipeline of the nitrogen monoxide gas cylinder 3 is respectively connected to the A2 outlet 10 of the first electromagnetic three-way valve 4 and the B2 inlet 13 of the second electromagnetic three-way valve 5. The A3 outlet 11 of the first electromagnetic three-way valve 4 is connected to the B1 inlet 12 of the second electromagnetic three-way valve 5. The B3 outlet 14 of the second electromagnetic three-way valve 5 is connected to the gas ventilation device, and a nitrogen-oxygen sensor to be tested is installed in the gas ventilation device.

[0026] By setting the first electromagnetic three-way valve 4 and the second electromagnetic three-way valve 5, the on and off of the nitrogen monoxide gas output pipeline can be realized by controlling the connection states of the first electromagnetic three-way valve 4 and the second electromagnetic three-way valve 5. And after the nitrogen monoxide gas output pipeline is turned off, the residual nitrogen monoxide gas in the pipeline will not enter the gas ventilation device to affect the purity of the test gas, thereby improving the accuracy of the test results.

[0027] Specifically, as Figures 2 to 4As shown in the figure, the ventilation device includes a bottom plate 15. A hollow shaft 16 is provided on the top surface of the bottom plate 15. A test cavity 17 is provided inside the hollow shaft 16. An air inlet interface 18 communicating with the test cavity 17 is provided on the top surface of the hollow shaft 16. The air inlet interface 18 is used to communicate with the B3 outlet 14 of the second electromagnetic three-way valve 5. A through hole 19 communicating with the test cavity 17 is opened on the bottom surface of the bottom plate 15. The through hole 19 is used to install the probe of the nitrogen-oxygen sensor to be tested. The gas output by the gas distribution device is introduced into the test cavity 17 through the air inlet interface 18 for mixing, and the nitrogen-oxygen sensor to be tested is tested.

[0028] Further, the inner diameter of the through hole 19 is smaller than the inner diameter of the test cavity 17. The bottom end face of the test cavity 17 forms an annular step 20 for installing the probe of the nitrogen-oxygen sensor to be tested in the through hole 19, which facilitates the installation of the nitrogen-oxygen sensor.

[0029] Preferably, a bushing 21 is sleeved outside the hollow shaft 16. The inner diameter of the bushing 21 matches the outer diameter of the hollow shaft 16. A buffer cavity 22 is provided inside the bushing 21. An air vent hole 23 communicating with the buffer cavity 22 is opened on the side wall of the hollow shaft 16. An air outlet hole 24 communicating with the buffer cavity 22 is opened on the side wall of the bushing 21. The air outlet hole 24 is communicated with the air inlet interface 18 of the adjacent ventilation device through a pipeline. By providing a buffer cavity 22 inside the bushing 21, the gas in the test cavity 17 can be introduced into the buffer cavity 22 through the air vent hole 23, avoiding excessive pressure in the test cavity 17 from affecting the sensor's signal acquisition. By opening the air outlet hole 24 on the side wall of the bushing 21, it is convenient to connect multiple ventilation devices in series to realize the synchronous testing of multiple nitrogen-oxygen sensors, greatly improving the testing efficiency. The air outlet hole 24 of the last series-connected ventilation device is the tail gas discharge hole.

[0030] Preferably, a plurality of air vent holes 23 are provided. The plurality of air vent holes 23 are evenly arranged circumferentially along the side wall of the hollow shaft 16. By providing a plurality of air vent holes 23, the influence of pressure differences in different directions on the sensor's testing can be avoided, making the pressure in different directions of the sensor the same.

[0031] Further, a first shaft shoulder 25 is provided outside the hollow shaft 16. The outer diameter of the first shaft shoulder 25 matches the inner diameter of the buffer cavity 22. The first shaft shoulder 25 is inserted into the buffer cavity 22 from the bottom end of the bushing 21. The bottom end face of the bushing 21 abuts against the top surface of the bottom plate 15. By providing the first shaft shoulder 25, it is convenient to install and position the bushing 21.

[0032] Further, a second shoulder 26 is provided outside the hollow shaft 16. The bottom surface of the second shoulder 26 is adjacent to the top surface of the first shoulder 25. The outer diameter of the second shoulder 26 is smaller than that of the first shoulder 25 and larger than the inner diameter of the air inlet interface 18. The top surface of the second shoulder 26 abuts against the top surface of the buffer chamber 22. The vent hole 23 penetrates through the side wall of the second shoulder 26. By providing the second shoulder 26, on the one hand, the volume of the buffer chamber 22 can be reduced, reducing the consumption of the test gas. On the other hand, it is also convenient for the installation and sealing of the bushing 21.

[0033] Specifically, through holes 27 are provided through the top surface of the bushing 21 and the top surface of the bottom plate 15. The bushing 21 and the bottom plate 15 are connected by bolts. After the bolts pass through the through holes 27 in the bushing 21 and the bottom plate 15, they are locked by nuts, which is convenient for installation.

[0034] Further, a first annular groove 28 is provided on the top surface of the bottom plate 15, and a second annular groove 29 is provided on the top surface of the second shoulder 26. Sealing rings are provided in the first annular groove 28 and the second annular groove 29. By providing the first annular groove 28 and the second annular groove 29, it is convenient to install sealing rings between the top surface of the bottom plate 15 and the bottom surface of the bushing 21 and between the top surface of the test cavity 17 and the top surface of the second shoulder 26, which can prevent the leakage of the test gas.

[0035] Preferably, the first shoulder 25, the second shoulder 26, the hollow shaft 16 and the bottom plate 15 are integrally formed, and the structure is more firm.

[0036] The test process of the test device in this embodiment is as follows:

[0037] 1) For the gas distribution device:

[0038] When the required test gas contains nitric oxide, control the A1 inlet 9 and the A2 outlet 10 of the first solenoid valve to be connected, and the A3 outlet 11 to be closed; control the B2 inlet 13 and the B3 outlet 14 of the second electromagnetic three-way valve 5 to be connected, and the B1 inlet 12 to be closed; the nitrogen and oxygen output from the nitrogen cylinder 1 and the oxygen cylinder 2 respectively pass through the nitrogen flowmeter 6 and the oxygen flowmeter 7 on their respective output pipelines and enter the first solenoid valve from the A1 inlet 9, then flow out from the A2 outlet 10 of the first solenoid valve, and converge with the nitric oxide gas output from the nitric oxide cylinder 31 and enter the second solenoid valve from the B2 inlet 13, and finally output from the B3 outlet 14 of the second solenoid valve;

[0039] When the required test gas does not contain nitric oxide, control the first solenoid valve so that its A1 inlet 9 is communicated with its A3 outlet 11, and its A2 outlet 10 is closed; control the second electromagnetic three-way valve 5 so that its B1 inlet 12 is communicated with its B3 outlet 14, and its B2 inlet 13 is closed; the nitrogen and oxygen output from the nitrogen cylinder 1 and the oxygen cylinder 2 respectively pass through the nitrogen flowmeter 6 and the oxygen flowmeter 7 on their respective output pipelines, then enter the first solenoid valve from the A1 inlet 9, flow out from the A3 outlet 11 of the first solenoid valve, then enter the second solenoid valve from the B1 inlet 12, and finally output from the B3 outlet 14 of the second solenoid valve;

[0040] If the test gas used in the test conducted before this test (the required test gas does not contain nitric oxide) contains nitric oxide, then before conducting this test, first use the mixed gas of nitrogen and oxygen output from the nitrogen cylinder 1 and the oxygen cylinder 2 to flush out the residual nitric oxide gas in the first solenoid valve and the second solenoid valve (continuously open for 10 s), and then connect the ventilation device to the B3 outlet 14 of the second solenoid valve, so as to ensure that the test gas does not contain the residual nitric oxide from the previous test.

[0041] 2) For the ventilation device:

[0042] First, connect multiple ventilation devices with nitrogen-oxygen sensors to be tested in series in turn. The air inlet interface 18 of the current ventilation device is communicated with the air outlet hole 24 of the previous ventilation device through a hose, the air outlet hole 24 of the current ventilation device is communicated with the air inlet interface 18 of the next ventilation device, the air inlet interface 18 of the first ventilation device is communicated with the B3 outlet 14 of the second electromagnetic three-way valve 5 through a hose, and the air outlet hole 24 of the last ventilation device is communicated with the tail gas treatment device through a hose; the test gas output by the gas distribution device enters the test cavity 17 of the first ventilation device through the air inlet interface 18, generates an electrochemical reaction with the probe of the nitrogen-oxygen sensor to obtain a test signal, and the remaining gas enters the buffer cavity 22 through the ventilation hole 23, then enters the test cavity 17 of the next ventilation device in series through the air outlet hole 24, the hose and the air inlet interface 18 for testing, so as to realize the synchronous testing of multiple nitrogen-oxygen sensors.

[0043] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A nitrogen oxygen sensor testing device, characterized in that: The invention comprises a gas distribution device and a ventilation device, wherein the gas distribution device comprises a nitrogen cylinder (1), an oxygen cylinder (2), a nitric oxide cylinder (3), a first electromagnetic three-way valve (4) and a second electromagnetic three-way valve (5); a nitrogen flowmeter (6), an oxygen flowmeter (7) and a nitric oxide flowmeter (8) are respectively installed on the output pipelines of the nitrogen cylinder (1), the oxygen cylinder (2) and the nitric oxide cylinder (3); the output pipelines of the nitrogen cylinder (1) and the oxygen cylinder (2) are connected to the first electromagnetic three-way valve (4) and the second electromagnetic three-way valve (5). The output pipeline of the nitric oxide gas cylinder (3) is respectively connected to the A2 outlet (10) of the first electromagnetic three-way valve (4) and the B2 inlet (13) of the second electromagnetic three-way valve (5); the A3 outlet (11) of the first electromagnetic three-way valve (4) is connected to the B1 inlet (12) of the second electromagnetic three-way valve (5); the B3 outlet (14) of the second electromagnetic three-way valve (5) is connected to the ventilation device, and the nitrogen oxygen sensor to be tested is installed in the ventilation device.

2. A nitrogen oxygen sensor testing device as claimed in claim 1, characterized in that: The ventilation device comprises a bottom plate (15), a hollow shaft (16) is provided on the top surface of the bottom plate (15), a test cavity (17) is provided inside the hollow shaft (16), an air inlet interface (18) connected to the test cavity (17) is provided on the top surface of the hollow shaft (16), and the air inlet interface (18) is used to connect to the B3 outlet (14) of the second electromagnetic three-way valve (5); a through hole (19) connected to the test cavity (17) is opened on the bottom surface of the bottom plate (15), and the through hole (19) is used to install a probe of a nitrogen oxygen sensor to be tested.

3. A nitrogen oxygen sensor testing device as claimed in claim 2, characterized in that: The inner diameter of the through hole (19) is smaller than the inner diameter of the test cavity (17), and the bottom end surface of the test cavity (17) forms an annular step (20) in the through hole (19) for mounting a probe of the nitrogen oxygen sensor to be tested.

4. A nitrogen oxygen sensor testing device as claimed in claim 2, characterized in that: The hollow shaft (16) is externally sleeved with a shaft sleeve (21), the inner diameter of the shaft sleeve (21) matches the outer diameter of the hollow shaft (16), a buffer chamber (22) is provided inside the shaft sleeve (21), a vent hole (23) connected to the buffer chamber (22) is provided on the side wall of the hollow shaft (16), an air outlet hole (24) connected to the buffer chamber (22) is provided on the side wall of the shaft sleeve (21), and the air outlet hole (24) is connected to an air inlet interface (18) of an adjacent ventilation device through a pipeline.

5. A nitrogen oxygen sensor testing device as claimed in claim 4, characterized in that: A plurality of the vent holes (23) are provided, and the plurality of the vent holes (23) are evenly arranged along the circumference of the side wall of the hollow shaft (16).

6. A nitrogen oxygen sensor testing device as claimed in claim 4, characterized in that: The hollow shaft (16) is provided with a first shaft shoulder (25) on the outside, the outer diameter of the first shaft shoulder (25) matches the inner diameter of the buffer cavity (22), the first shaft shoulder (25) is inserted into the buffer cavity (22) from the bottom end of the shaft sleeve (21), and the bottom end surface of the shaft sleeve (21) abuts against the top surface of the bottom plate (15).

7. A nitrogen oxygen sensor testing device as claimed in claim 6, characterized in that: A second shoulder (26) is provided on the outside of the hollow shaft (16), the bottom surface of the second shoulder (26) is adjacent to the top surface of the first shoulder (25), the outer diameter of the second shoulder (26) is smaller than the outer diameter of the first shoulder (25) and larger than the inner diameter of the air inlet interface (18), the top surface of the second shoulder (26) is in contact with the top surface of the buffer cavity (22), and the vent hole (23) passes through the side wall of the second shoulder (26).

8. A nitrogen oxygen sensor testing device as claimed in claim 7, characterized in that: The top surface of the shaft sleeve (21) and the top surface of the bottom plate (15) are both provided with penetrating mounting holes (27), and the shaft sleeve (21) and the bottom plate (15) are connected by bolts.

9. A nitrogen oxygen sensor testing device as claimed in claim 8, characterized in that: The top surface of the bottom plate (15) is provided with a first annular groove (28), the top surface of the second shaft shoulder (26) is provided with a second annular groove (29), and sealing rings are provided in the first annular groove (28) and the second annular groove (29).

10. A nitrogen oxygen sensor testing device as claimed in claim 7, characterized in that: The first shaft shoulder (25), the second shaft shoulder (26), the hollow shaft (16) and the bottom plate (15) are integrally formed.

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