Nitrogen-oxygen sensor with reference detection head and anomaly detection method thereof
By designing a structure with a reference detection head in the nitrogen oxygen sensor, collecting and comparing the reference voltage difference and current difference, the problem of the existing nitrogen oxygen sensor lacking self-detection function is solved, and the accurate abnormal detection of the nitrogen oxygen sensor and the accuracy and effectiveness of the data are achieved.
Patent Information
- Application Number
- CN202411846310.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-16
- Publication Date
- 2025-03-11
AI Technical Summary
Existing nitrogen oxygen sensors lack self-detection function and cannot effectively judge whether they are abnormal, resulting in inaccuracy and effectiveness of the detection results.
A nitrogen oxygen sensor with a reference detection head is designed, including a shunt device, a reference detection head with a consistent structure and a measurement detection head. The reference electrode in the reference detection head is in the closed chamber. The reference electrode in the measurement detection head is in communication with external air. By collecting and comparing the reference voltage difference and current difference, it is determined whether the detection head is abnormal.
Accurate abnormal detection of nitrogen oxygen sensors is achieved, ensuring the accuracy and effectiveness of detection data, reducing the chance of misjudgment, and providing a basis for the use of nitrogen oxygen sensors in emergencies.
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Figure CN119595736A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a nitrogen oxygen sensor, and more particularly to a nitrogen oxygen sensor with a reference detection head and an abnormality detection method thereof. Background Art
[0002] With the development of the automobile industry, vehicles have brought convenience to people's daily lives, but also pollution. Automobile exhaust emissions have caused serious pollution to the atmosphere, among which nitrogen oxides (NOx) are one of the main pollutants. Nitrogen oxide sensors are the main means of detecting automobile emissions of nitrogen oxides (NOx).
[0003] Currently, most reference electrodes of nitrogen and oxygen sensors are directly connected to the external atmosphere as standard gas. However, the composition of the external gas will change due to changes in the external environment, and may even be subject to sudden pollution, which will cause a large change in the oxygen content of the gas in the reference electrode, resulting in errors in the detection results.
[0004] Existing nitrogen oxide sensors lack self-detection functions. As the use time increases, the sensor parts will age and fail due to various reasons. Since the sensor cannot detect its own hardware status, it cannot ensure whether the instrument is normal during the detection process, and thus cannot guarantee the accuracy and effectiveness of the detected data. Summary of the invention
[0005] The technical problem to be solved by the present invention is to provide a nitrogen oxide sensor with a reference detection head and an abnormality detection method thereof in view of the deficiencies in the prior art, which can effectively determine whether the nitrogen oxide sensor is abnormal and accurately identify the abnormality.
[0006] A nitrogen oxygen sensor with a reference detection head described in the present invention comprises a shunt device and a reference detection head and a measuring detection head with the same structure; the shunt device is provided with two exhaust output ends, and the two exhaust output ends are respectively connected to the input ends of the reference detection head and the measuring detection head in a one-to-one correspondence; the reference detection head is provided with a closed chamber, in which a reference electrode 1 is installed; the measuring detection head is provided with an open chamber, in which a reference electrode 2 is installed.
[0007] Preferably, a voltage detection device is provided between the reference electrode 1 and the reference electrode 2.
[0008] Preferably, the closed chamber is filled with standard air; and the open chamber is provided with an external air inlet.
[0009] A method for detecting abnormality of a nitrogen oxygen sensor having a reference detection head, the method comprising the following steps:
[0010] Step 1: Collect the reference voltage difference ΔV between reference electrode 1 and reference electrode 2 参 ;
[0011] Step 2: Determine the reference voltage difference ΔV 参 The difference from the preset standard reference voltage is ΔV 参预 If ΔV 参 >ΔV 参预 , then execute the detection head abnormal alarm program; if ΔV 参 ≤ΔV 参预 , then go to step three;
[0012] Step 3: Collect the output current of the measuring electrode of the reference detection head as the reference current I 量1 , collect the output current of the measuring electrode of the measuring detection head as the measuring current I 量2 , and calculate the reference current I 量1 With the measured current I 量2 The current difference ΔI;
[0013] Step 4: Determine the difference between the current difference ΔI and the preset difference ΔI 预 The size relationship between them is, if ΔI>ΔI 预 , then execute the electrode abnormality alarm procedure; if ΔI≤ΔI 预 , then the measured current I 量2 The measurement results of the nitrogen oxide sensor are input into the NOx detection system.
[0014] Preferably, the detection head abnormality alarm procedure is specifically:
[0015] Set N monitoring cycles 1, and collect the reference voltage difference ΔV in each monitoring cycle 1 in sequence 参 , and at the same time determine the reference voltage difference ΔV within each monitoring cycle 参 The difference from the standard reference voltage is ΔV 参预 If the ΔV 参 ≤ΔV 参预 , then exit the detection head abnormal alarm program and execute step 3; if ΔV within N monitoring cycles 参 >ΔV 参预 , then a reference electrode abnormality alarm signal is generated.
[0016] Preferably, the electrode abnormality alarm procedure is specifically as follows: setting M monitoring cycles 2, calculating the current difference ΔI in each monitoring cycle 2 in sequence, and determining the current difference ΔI in each monitoring cycle 2 and the difference ΔI 预 If ΔI≤ΔI in any of the monitoring periods 2, 预, then exit the electrode abnormality alarm program; if ΔI>ΔI within M monitoring cycles 预 , then an abnormal alarm signal of the measuring electrode is generated.
[0017] Preferably, if the ΔI in the M monitoring cycles is greater than ΔI 预 , the ΔI obtained in each monitoring cycle two is sorted in the execution order of the M monitoring cycles two to obtain a ΔI sequence; the order size relationship in the ΔI sequence is analyzed, and if the current difference ΔI in the ΔI sequence decreases successively, a measurement electrode abnormality early warning warning is generated, and the electrode abnormality alarm program is exited.
[0018] Preferably, if the current difference ΔI in the ΔI sequence decreases successively, the current difference ΔI in the last monitoring cycle 2 is obtained, and the current difference ΔI in the last monitoring cycle 2 and the difference ΔI are calculated. 预 If ΔI / ΔI 预 =K, a measurement electrode abnormality warning is generated and the electrode abnormality alarm program is exited; wherein, K≤105%.
[0019] Beneficial Effects
[0020] The advantages of the present invention are:
[0021] 1. Design two detection heads, and place the reference electrode 1 in the reference detection head in a closed chamber that is not connected to the outside world. The chamber is filled with standard air in advance, and the air composition in the closed chamber can be kept constant and standard, effectively avoiding the influence of abnormal external gases on the reference electrode 1. Such a design effectively avoids the problem that the oxygen concentrations of the two reference electrodes are not much different due to the two chambers of reference electrode 1 and reference electrode 2 inhaling air from the outside at the same time, and thus it is impossible to detect whether the reference electrode is abnormal. Accurate reference data is obtained to ensure the normal operation of the abnormality detection system.
[0022] 2. During the abnormality analysis process, the data of the reference electrode and the measuring electrode are tested separately. This can effectively determine whether the abnormality occurs at the reference electrode position or the measuring electrode position during the detection process, and can obtain the cause of the abnormal data. The abnormality can be accurately located, which is conducive to further troubleshooting.
[0023] 3. When an abnormality occurs in the reference electrode or the measuring electrode, by further measuring the data within the set multiple monitoring cycles and performing abnormality analysis again, it can effectively rule out whether the current abnormality is caused by accidental errors, ensuring the accuracy of abnormality analysis and reducing the chance of misjudgment.
[0024] 4. For the measuring electrodes, the present invention also adopts sequence judgment and the final value judgment analysis of the last monitoring cycle, which can further judge the controllability of the identified abnormality and provide a basis for activating the nitrogen oxide sensor in an emergency. BRIEF DESCRIPTION OF THE DRAWINGS
[0025] Figure 1 This is a schematic diagram of the internal modular structure of the nitrogen oxygen sensor of the present invention;
[0026] Figure 2 It is a schematic diagram of the structure of the nitrogen oxygen sensor and its detection system of the present invention;
[0027] Figure 3 The figure is a flow chart of the abnormality detection method of the present invention. DETAILED DESCRIPTION
[0028] The present invention will be further described below in conjunction with the embodiments, but it does not constitute any limitation to the present invention. Any limited number of modifications made by anyone within the scope of the claims of the present invention are still within the scope of the claims of the present invention.
[0029] Embodiment 1
[0030] See also Figure 1-Figure 2 The present invention discloses a nitrogen oxygen sensor with a reference detection head, comprising a flow dividing device and a reference detection head and a measuring detection head with the same structure. The flow dividing device is provided with two exhaust gas output ends, and the two exhaust gas output ends are respectively connected with the input ends of the reference detection head and the measuring detection head in a one-to-one correspondence, and the exhaust gas is respectively sent to the reference detection head and the measuring detection head with the same gas volume. Both detection heads are composed of a diffusion layer 1, an impurity removal electrode, a fixed electrode, a diffusion layer 2, an auxiliary pump electrode, a measuring electrode, a common electrode and a reference electrode. The diffusion layer 1 is the input end of the detection head, which first contacts with the exhaust gas. The difference between the two detection heads is that: a closed chamber is provided in the reference detection head, a reference electrode 1 is installed in the closed chamber, and standard air is filled in the closed chamber. An open chamber is provided in the measuring detection head, a reference electrode 2 is installed in the open chamber, and an external air inlet is provided in the open chamber. A voltage detection device is provided between the reference electrode 1 and the reference electrode 2.
[0031] The exhaust gas enters the two detection heads through the diversion device. Figure 1 As shown in the figure, the upper one is the reference detection head, and the lower one is the measurement detection head. First, it enters the first chamber through the diffusion layer 1. There are impurity removal electrodes and oxygen determination electrodes in the first chamber. Among them, the impurity removal electrode is responsible for oxidizing and removing impurities such as CO and HC in the exhaust gas. A voltage monitoring device is set between the impurity removal electrode and the reference electrode, and its voltage value V 杂参1 The larger the value, the greater the difference in oxygen concentration between the two electrodes. The impurity removal electrode has a factory preset value of V 杂参-预According to V 杂参-预 and V 杂参1 The difference is used to adjust the voltage V 杂1 and current I 杂1 The size of the impurities is removed until V 杂参1 Reach V 杂参-预 The value of .
[0032] After the impurities in the exhaust gas are fully removed, it goes to the oxygen electrode for deoxygenation to prevent excessive oxygen concentration from affecting the test results. 氧参-预 and V 氧参1 The difference is used to adjust the voltage V 氧1 and current I 氧1 The size of the deoxygenation is carried out until V 氧1 Reference reaches V 氧参-预 The value of .
[0033] The deoxygenated gas enters the second chamber through the diffusion layer 2, and the second chamber contains an auxiliary pump electrode and a measuring electrode. The auxiliary pump electrode is used to convert NO2 in the exhaust gas into NO and further reduce the other oxygen content to be measured. 泵参-预 and V 泵参1 The difference is used to adjust the voltage V 泵1 and current I 泵1 The size of NO2 is converted until V 泵参1 Reach V 泵参-预 The value of .
[0034] Finally, the gas that has been treated and meets the standards is discharged to the measuring electrode for detection. The measuring electrode pumps out all the O2 produced by the NO reaction, and the current I 量1 or I 量2 Characterizes NO in exhaust gas X concentration.
[0035] The chamber of the reference electrode 2 of the measuring detection head of the present invention is connected to the outside, that is, the air therein comes directly from the outside atmosphere. The reference electrode 1 of the reference detection head is in a closed chamber, which is not connected to the outside during operation. The air therein is standard air filled in advance. The standard air and the closed cavity can keep the air composition of the reference electrode constant and standard, which plays a better comparison role. A voltage monitoring device is set between the reference electrode 1 and the reference electrode 2, and its value V 参 The larger the value, the greater the difference in oxygen concentration between the two electrodes. 参 Greater than the preset V 参预 When the oxygen concentration difference between the two reference electrodes is too large, there may be a problem with the inhaled gas or the reference electrode.
[0036] Embodiment 2
[0037] like Figure 3 As shown, based on the above-mentioned nitrogen oxygen sensor with a reference detection head, this embodiment provides a method for detecting abnormality of a nitrogen oxygen sensor, and the method includes the following steps:
[0038] Step 1: Collect the reference voltage difference ΔV between reference electrode 1 and reference electrode 2 参 . Among them, ΔV 参 =V 参 -V 参预。
[0039] Step 2: Determine the reference voltage difference ΔV 参 The difference from the preset standard reference voltage is ΔV 参预 If ΔV 参 >ΔV 参预 , then execute the detection head abnormal alarm program; if ΔV 参 ≤ΔV 参预 , then go to step 3. That is, first determine whether the oxygen concentration difference between the two reference electrodes is less than the preset oxygen concentration difference. If it is greater than the preset oxygen concentration difference, it means that there may be a problem at the reference electrode. Therefore, the detection head abnormal alarm program is executed first, rather than directly collecting the reference current I of the measurement electrode. 量1 .
[0040] In order to exclude the possibility that the abnormality is caused by accidental errors, the following improvements were made to the abnormality alarm program of the detection head:
[0041] Set N monitoring cycles 1, and collect the reference voltage difference ΔV in each monitoring cycle 1 in turn. 参 , and at the same time determine the reference voltage difference ΔV within each monitoring cycle 参 The difference from the standard reference voltage is ΔV 参预 If the ΔV 参 ≤ΔV 参预 , then exit the detection head abnormal alarm program and execute step 3; if ΔV 参 >ΔV 参预 , then a reference electrode abnormality alarm signal is generated.
[0042] That is, when ΔV first appears 参 >ΔV 参预 When the system fails to meet the requirement, the system will discard the current data and re-measure the data of the NOx sensor and input it into the system for analysis, that is, the monitoring work of the first monitoring cycle 1 will be carried out. If the data is still abnormal, the data will be re-measured and input into the abnormal detection system for analysis again. This will continue until ΔV 参 ≤ΔV 参预, or N monitoring cycles are completed. This mechanism can effectively avoid the problem of abnormal false alarms caused by accidental errors.
[0043] Step 3: Collect the current of the measuring electrode of the reference detection head as the reference current I 量1 , collect the current of the measuring electrode of the detection head as the measuring current I 量2 , and calculate the reference current I 量1 With the measured current I 量2 The current difference ΔI.
[0044] Step 4: Determine the difference between the current difference ΔI and the preset difference ΔI 预 The size relationship between them is, if ΔI>ΔI 预 , then execute the electrode abnormality alarm procedure; if ΔI≤ΔI 预 , then the measured current I 量2 The measurement results of the nitrogen oxide sensor are input into the NOx detection system.
[0045] Similarly, in order to exclude the possibility that the abnormality is caused by accidental error, M monitoring cycles 2 are set in the electrode abnormality alarm program, and the current difference ΔI in each monitoring cycle 2 is calculated in turn, and the current difference ΔI in each monitoring cycle 2 is judged. 预 If ΔI≤ΔI in any monitoring period 2, 预 , then exit the electrode abnormal alarm program; if ΔI>ΔI within M monitoring cycles 预 , then an abnormal alarm signal of the measuring electrode is generated.
[0046] Since the reference electrode directly affects whether the measured parameters of the measuring electrode are normal, the abnormality of the reference electrode will more obviously reflect the abnormality of the detection head. If the reference electrode is normal and the measuring electrode is abnormal, the nitrogen oxide sensor can still be used for emergency under emergency conditions. Therefore, this embodiment adds an emergency warning mechanism based on the measuring electrode on the basis of the above.
[0047] Specifically, if ΔI in M monitoring cycles is greater than ΔI 预 , then the ΔI obtained in each monitoring cycle two is sorted in the execution order of the M monitoring cycles two to obtain a ΔI sequence; the order size relationship in the ΔI sequence is analyzed. If the current difference ΔI in the ΔI sequence decreases successively, it means that the measuring electrode has a tendency to be normal within the M monitoring cycles two, and its abnormality is a controllable abnormality. At this time, a measuring electrode abnormality early warning warning is generated, and the electrode abnormality alarm program is exited, and the nitrogen oxide sensor also works normally.
[0048] In order to further determine whether the abnormality of the measuring electrode is a benign controllable abnormality, in this embodiment, if the current difference ΔI in the ΔI sequence decreases successively, the current difference ΔI in the last monitoring cycle 2 is obtained, and the current difference ΔI in the last monitoring cycle 2 and the difference ΔI are calculated. 预 If ΔI / ΔI 预 =K, an abnormality warning of the measuring electrode is generated, and the abnormality alarm program of the electrode is exited; wherein, K≤105%. That is, the current difference ΔI in the last monitoring cycle 2 is greater than the difference ΔI 预 If the error is within 5% of the error, the abnormality of the measuring electrode is considered to be a benign and controllable abnormality, and the nitrogen oxide sensor can be used for emergency purposes.
[0049] The above is only a preferred embodiment of the present invention. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the structure of the present invention, which will not affect the effect of the implementation of the present invention and the practicality of the patent.
Claims
1. A nitrogen oxygen sensor with a reference detection head, characterized in that: It includes a shunt device and a reference detection head and a measuring detection head with the same structure; the shunt device is provided with two exhaust output ends, and the two exhaust output ends are respectively connected with the input ends of the reference detection head and the measuring detection head in a one-to-one correspondence; the reference detection head is provided with a closed chamber, and a reference electrode 1 is installed in the closed chamber; the measuring detection head is provided with an open chamber, and a reference electrode 2 is installed in the open chamber.
2. A nitrogen oxygen sensor with a reference detection head according to claim 1, characterized in that: A voltage detection device is provided between the reference electrode 1 and the reference electrode 2.
3. The nitrogen oxygen sensor with a reference detection head according to claim 1, characterized in that: The closed chamber is filled with standard air; the open chamber is provided with an external air inlet.
4. A method for detecting abnormality of a nitrogen oxide sensor having a reference detection head according to any one of claims 1 to 3, characterized in that: The method comprises the following steps: Step 1: Collect the reference voltage difference ΔV between reference electrode 1 and reference electrode 2 参 ; Step 2: Determine the reference voltage difference ΔV 参 The difference from the preset standard reference voltage is ΔV 参预 If ΔV 参 >ΔV 参预 , then execute the detection head abnormal alarm program; if ΔV 参 ≤ΔV 参预 , then go to step three; Step 3: Collect the output current of the measuring electrode of the reference detection head as the reference current I 量1 , collect the output current of the measuring electrode of the measuring detection head as the measuring current I 量2 , and calculate the reference current I 量1 With the measured current I 量2 The current difference ΔI; Step 4: Determine the difference between the current difference ΔI and the preset difference ΔI 预 The size relationship between them is, if ΔI>ΔI 预 , then execute the electrode abnormality alarm program; If ΔI≤ΔI 预 , then the measured current I 量2 The measurement results of the nitrogen oxide sensor are input into the NOx detection system.
5. The anomaly detection method according to claim 4, characterized in that: The detection head abnormality alarm procedure is specifically as follows: Set N monitoring cycles 1, and collect the reference voltage difference ΔV in each monitoring cycle 1 in sequence 参 , and at the same time determine the reference voltage difference ΔV within each monitoring cycle 参 The difference from the standard reference voltage is ΔV 参预 If the ΔV 参 ≤ΔV 参预 , then exit the detection head abnormal alarm program and execute step 3; if ΔV within N monitoring cycles 参 >ΔV 参预 , then a reference electrode abnormality alarm signal is generated.
6. The anomaly detection method according to claim 4, characterized in that: The electrode abnormality alarm procedure is specifically as follows: setting M monitoring cycles 2, calculating the current difference ΔI in each monitoring cycle 2 in turn, and determining the current difference ΔI in each monitoring cycle 2 and the difference ΔI 预 If ΔI≤ΔI in any of the monitoring periods 2, 预 , then exit the electrode abnormality alarm program; If ΔI>ΔI within M monitoring cycles 预 , then an abnormal alarm signal of the measuring electrode is generated.
7. The abnormality detection method according to claim 6, characterized in that: If the ΔI in the M monitoring cycles is greater than ΔI 预 , the ΔI obtained in each monitoring cycle two is sorted in the execution order of the M monitoring cycles two to obtain a ΔI sequence; the order size relationship in the ΔI sequence is analyzed, and if the current difference ΔI in the ΔI sequence decreases successively, a measurement electrode abnormality early warning warning is generated, and the electrode abnormality alarm program is exited.
8. The abnormality detection method according to claim 7, characterized in that: If the current difference ΔI in the ΔI sequence decreases successively, the current difference ΔI in the last monitoring cycle 2 is obtained, and the current difference ΔI in the last monitoring cycle 2 and the difference ΔI are calculated. 预 If ΔI / ΔI 预 =K, a measurement electrode abnormality warning is generated and the electrode abnormality alarm program is exited; wherein, K≤105%.