Nitrogen-oxygen sensor and working temperature control method and self-diagnosis method thereof
By adopting a bionic nasal protective cover and a stepped air cavity structure in the nitrogen oxygen sensor, combined with working temperature control and self-diagnosis methods, the problems of slow sensor response speed and easy damage to ceramic materials are solved, achieving more efficient and reliable nitrogen oxygen detection.
Patent Information
- Application Number
- CN202411699047.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-26
- Publication Date
- 2025-04-04
AI Technical Summary
Existing nitrogen and oxygen sensors have slow response speed in complex environments, reduced detection accuracy, and ceramic materials are susceptible to sudden temperature changes, resulting in structural damage and reduced performance.
A nitrogen oxygen sensor was designed, using a bionic nasal protective cover and a stepped air cavity structure to improve the airflow flow velocity and pressure distribution; at the same time, working temperature control methods and self-diagnosis methods were adopted to optimize the sensor's working environment and fault diagnosis through PID closed-loop control and pump oxygen voltage calibration.
It improves the response speed and detection accuracy of the nitrogen oxygen sensor, enhances its adaptability and reliability in variable environments, and reduces the risk of failure and cost of use.
Smart Images
Figure CN119757465A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a nitrogen oxygen sensor, and more particularly to a nitrogen oxygen sensor and a working temperature control method and a self-diagnosis method thereof. Background Art
[0002] As an important tool for detecting NOx concentration in exhaust gas, the measurement accuracy and response speed of nitrogen oxide sensor directly affect the effect of exhaust emission monitoring.
[0003] The concentration of NOx in exhaust gas is relatively low. For low-concentration gas, the airflow pattern and cavity design in the detection system have a great impact on the sensitivity, stability, and accuracy of the detection system, so the detection system needs to be strictly designed. At the same time, the existing nitrogen oxide sensors are easily interfered by other gas components in complex environments, affecting the detection accuracy.
[0004] In addition, due to the relatively complex exhaust gas treatment environment, ceramic materials gradually accumulate damage due to multiple temperature shocks. Under the action of thermal stress, cracks may appear on the surface of the ceramic material, weakening the integrity of the overall structure of the sensor, thereby affecting its performance and requiring regular calibration and maintenance, which also increases the cost and complexity of use.
[0005] Regarding the above problems, although the mainstream nitrogen oxide sensors in the current market can alleviate the impact of exhaust gas changes on sensor performance to a certain extent, they have problems such as slow response speed and decreased detection performance after long-term operation, which causes the exhaust gas after-treatment system to be unable to effectively control the input of urea injection amount in time, thereby reducing the rapid and accurate monitoring capabilities of the nitrogen oxide sensors. Summary of the invention
[0006] The technical problem to be solved by the present invention is to provide a nitrogen oxide sensor and a working temperature control method and a self-diagnosis method thereof in view of the deficiencies in the prior art, thereby improving the response speed and accuracy of the nitrogen oxide sensor.
[0007] A nitrogen oxygen sensor described in the present invention comprises a shell and a probe body installed in the shell; a bionic nasal protective cover is installed at the end of the shell, an air cavity is opened in the bionic nasal protective cover, and the air cavity is in a stepped structure that is narrow in front and wide in the back; an air intake section is provided at the front end of the bionic nasal protective cover, a plurality of air intake holes are opened in the air intake section, and a bionic guide structure imitating a canine nasal concha is provided in the air cavity above the air intake section.
[0008] As a further improvement, the air cavity consists of a front cavity, a middle cavity and a rear cavity, the cross-sectional areas of the front cavity, the middle cavity and the rear cavity increase successively, the front cavity is connected with the air intake section, the bionic guide structure is installed in the front cavity, and the rear cavity is connected with the inner cavity of the outer shell.
[0009] Furthermore, the diameter of the front cavity is 9-11 mm; the diameter of the middle cavity is 15-17 mm; and the diameter of the rear cavity is 17-19 mm.
[0010] As a further improvement, the air inlet section is composed of a cylindrical section with a diameter smaller than the diameter of the front cavity and a connecting section, and a plurality of air inlet holes are provided on the cylindrical section and the connecting section.
[0011] Furthermore, the bionic guide structure includes a plurality of guide plates; one ends of the plurality of guide plates are connected to each other to form a connection point consistent with the axis of the front cavity, and the other ends of the guide plates are connected to the inner wall of the front cavity.
[0012] Furthermore, three guide plates are provided, and the three guide plates are evenly distributed in the front cavity to divide the front cavity into three sub-cavities, and the areas of the air inlet holes mapped in the three sub-cavities are consistent.
[0013] Furthermore, the probe body extends into the middle cavity.
[0014] A method for controlling the working temperature of the nitrogen oxide sensor is characterized by obtaining the real-time working temperature of the nitrogen oxide sensor, and traversing historical data according to the real-time working temperature to query and predict the working condition change of the nitrogen oxide sensor from the historical data, and adjusting the heating data of the nitrogen oxide sensor according to the working condition change, and then preheating the nitrogen oxide sensor; judging whether the temperature of the nitrogen oxide sensor reaches a preset value of the preheating temperature, if not, heating the temperature of the nitrogen oxide sensor to the preset value through PID closed-loop control, if reached, controlling to keep the temperature of the nitrogen oxide sensor at the preset value, and when the internal combustion engine releases exhaust gas, keeping the temperature of the nitrogen oxide sensor at the preset value with a calibrated heating power according to the exhaust gas temperature of the exhaust gas.
[0015] A self-diagnosis method based on the nitrogen oxide sensor is characterized in that a limiting current Ip1 in a first chamber detection chamber of the nitrogen oxide sensor is obtained, and the limiting current Ip1 is compared with a preset range. If the limiting current Ip1 exceeds the preset range, the pump oxygen voltage of the nitrogen oxide sensor is calibrated through PID closed-loop control, and if the limiting current Ip1 still exceeds the preset range after a set number of calibrations, the operating data of the nitrogen oxide sensor is recorded as fault information, and a fault report is sent; if the limiting current Ip1 is within the preset range, it indicates that the nitrogen oxide sensor is operating normally.
[0016] Beneficial Effects
[0017] The advantages of the present invention are:
[0018] 1. The present invention effectively improves the flow velocity and pressure distribution of the airflow by adding a bionic electronic nose design, thereby enhancing the reaction efficiency between the sensor detection module and the exhaust gas.
[0019] 2. Through the design of the temperature control method, not only the response speed and accuracy of the nitrogen oxide sensor are improved, but also its adaptability and reliability in a changing environment are enhanced, and the working environment of the sensor is optimized.
[0020] 3. Through real-time fault diagnosis of the nitrogen oxide sensor system, the monitoring accuracy and reliability of the nitrogen oxide sensor can be improved, and the risk of excessive automobile emissions due to sensor failure can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Figure 1 Schematic diagram of the cross-sectional structure of the nitrogen oxygen sensor of the present invention;
[0022] Figure 2 This is a schematic diagram of the three-dimensional structure of the bionic nasal protective cover of the present invention;
[0023] Figure 3 It is a schematic diagram of the front cavity structure viewed from above of the present invention;
[0024] Figure 4 It is a schematic flow chart of a method for controlling the working temperature of a nitrogen oxygen sensor according to the present invention;
[0025] Figure 5 The figure is a flow chart of the self-diagnosis method of the nitrogen oxygen sensor of the present invention.
[0026] Among them: 1-shell, 2-probe body, 3-bionic nasal protection cover, 4-air cavity, 5-air inlet section, 6-guide plate, 7-air inlet hole, 41-front cavity, 42-middle cavity, 43-rear cavity, 51-cylindrical section, 52-connecting section. DETAILED DESCRIPTION
[0027] 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.
[0028] See also Figure 1-Figure 3A nitrogen oxygen sensor of the present invention comprises a shell 1 and a probe body 2 installed in the shell 1. A bionic nasal cavity protective cover 3 is installed at the end of the shell 1, and an air cavity 4 is opened in the bionic nasal cavity protective cover 3, and the air cavity 4 has a stepped structure that is narrow in front and wide in the back. Through the stepped increase structure of the air cavity 4 that is narrow in front and wide in the back, the nitrogen oxygen sensor can moderately reduce the flow rate of the gas entering the cavity while ensuring the overall response speed, thereby increasing the contact surface area of the airflow and the sensing area of the nitrogen oxygen sensor and the gas flow time. Specifically, the air cavity 4 is composed of a front cavity 41, a middle cavity 42 and a rear cavity 43, and the cross-sectional areas of the front cavity 41, the middle cavity 42 and the rear cavity 43 increase successively. The front cavity 41 is connected to the air inlet section 5, and the bionic flow guide structure is installed in the front cavity 41. The probe body 2 extends into the middle cavity 42, and the rear cavity 43 is connected to the inner cavity of the shell 1. This design can ensure that the nitrogen oxide sensor fully reacts with the gas being measured, so that the non-NO gas in the NOx mixed gas can be fully converted into NO gas in the second detection chamber of the nitrogen oxide sensor, thereby improving the accuracy of detection. In addition, the step-by-step increase in the cross-sectional area of the three cavities also ensures the uniform distribution of the flow velocity and pressure of the airflow. This design effectively improves the accuracy of the bionic gas cavity for NOx detection and realizes efficient detection of gas components. In this embodiment, the diameter of the front cavity 41 is 9 to 11 mm; the diameter of the middle cavity 42 is 15 to 17 mm; and the diameter of the rear cavity 43 is 17 to 19 mm.
[0029] The front end of the bionic nasal protective cover 3 is provided with an air intake section 5, and a plurality of air intake holes 7 are provided in the air intake section 5 to form an air intake hole array. While the exhaust gas enters the nitrogen oxygen sensor cavity through the air intake hole for detection, the air intake hole also acts as a sieve hole, allowing airflow to enter and preventing waste particles from entering. Air intake hole diameter size requirement: 0.8-0.9mm. Among them, the air intake section 5 is composed of a cylindrical section 51 and a connecting section 52 whose diameter is smaller than the diameter of the front cavity 41. A plurality of air intake holes 7 are provided on the cylindrical section 51 and the connecting section 52, which can effectively ensure the air intake volume.
[0030] A bionic flow guide structure imitating canine nasal concha is provided in the air cavity 4 above the air inlet section 5. Specifically, the bionic flow guide structure includes a plurality of flow guide plates 6; one end of the plurality of flow guide plates 6 are interconnected to form a connection point consistent with the axis of the front cavity 41, and the other end of the flow guide plate 6 is connected to the inner wall of the front cavity 41. The nasal concha structure of canine animals effectively guides the airflow into the nasal cavity, so that the gas can directly reach the olfactory area, thereby significantly improving its olfactory ability. In order to simulate this natural mechanism, the present invention designs a bionic flow guide structure in the front cavity of the probe. When the airflow just enters the detection probe, due to the cavity design of being narrow in front and wide in the back, the flow velocity at the air inlet is fast, the flow velocity in the middle cavity is slow, and turbulence is easily formed. If turbulence occurs in the sensor sensing area, the detection accuracy can be improved. However, if turbulence is formed too early, causing part of the gas to return to the air inlet, the air inlet pressure will increase, thereby blocking the gas from entering the chamber. Therefore, adding a baffle can effectively guide the flow, avoid the occurrence of turbulence before the airflow reaches the sensor sensing area, and make the airflow more evenly distributed in the front cavity. By introducing a through-type guide plate 6 in the entire structure, the structure of the electronic nose gas measurement chamber can be further optimized, making the airflow smoother and reducing the early generation of turbulence. This not only improves the efficiency of gas flow, but also helps to reduce the resistance that may occur in fluid dynamics. At the same time, the design effectively improves the distribution of the flow field, reduces the dead angles or uneven airflow areas that may be formed, and creates a smoother and more uniform gas flow environment.
[0031] In this embodiment, three guide plates 6 are provided, and the three guide plates 6 are evenly distributed in the front cavity 41 to divide the front cavity 41 into three sub-cavities, and the areas of the air inlet holes 7 mapped in the three sub-cavities are consistent, so that the airflow in the air cavity 4 is uniform.
[0032] like Figure 4As shown, a method for controlling the working temperature of the nitrogen oxide sensor based on the above is used to obtain the real-time working temperature of the nitrogen oxide sensor, and traverse the historical data according to the real-time working temperature, so as to query and predict the working condition change of the nitrogen oxide sensor from the historical data, and adjust the heating data of the nitrogen oxide sensor according to the working condition change, and then preheat the nitrogen oxide sensor, which can effectively prevent the phenomenon that the surface of the nitrogen oxide sensor of the ceramic element is easy to break under the temperature shock change. It is judged whether the temperature of the nitrogen oxide sensor reaches the preset value of the preheating temperature. If it is not reached, the temperature of the nitrogen oxide sensor is heated to the preset value through PID closed-loop control. If it is reached, the temperature of the nitrogen oxide sensor is controlled to be maintained at the preset value, and when the internal combustion engine releases the exhaust gas, the temperature of the nitrogen oxide sensor is maintained at the preset value according to the exhaust gas temperature of the exhaust gas with the calibrated heating power. After reaching the preset value, the exhaust gas is controlled to start to be released into the nitrogen oxide sensor, which not only ensures that the moisture in the exhaust gas will not damage the ceramic element, but also shortens the subsequent heating time of the sensor, improves the response speed of the nitrogen oxide sensor, and adapts to different environmental conditions. The heating power is adjusted through PID closed-loop control to ensure the constant working temperature of the nitrogen oxide sensor and reduce the interference of temperature fluctuations on gas detection of the pump unit.
[0033] As shown in FIG. 5 , a self-diagnosis method based on the nitrogen oxide sensor is used to obtain the limiting current Ip1 in the first chamber detection chamber of the nitrogen oxide sensor, and compare the limiting current Ip1 with the preset range. If the limiting current Ip1 exceeds the preset range, the pump oxygen voltage of the nitrogen oxide sensor is calibrated through PID closed-loop control, and if the limiting current Ip1 still exceeds the preset range after the set number of calibrations, the operating data of the nitrogen oxide sensor is recorded as fault information, and a fault report is sent. If the limiting current Ip1 is within the preset range, it means that the nitrogen oxide sensor is operating normally, so that the working status of the sensor can be monitored in real time and the fault can be accurately diagnosed.
[0034] 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, comprising a housing (1) and a probe body (2) installed in the housing (1); characterized in that: A bionic nasal cavity protective cover (3) is installed at the end of the shell (1), an air cavity (4) is provided in the bionic nasal cavity protective cover (3), and the air cavity (4) is a stepped structure that is narrow at the front and wide at the back. An air intake section (5) is provided at the front end of the bionic nasal cavity protective cover (3), and a plurality of air intake holes (7) are provided in the air intake section (5). A bionic flow guide structure that imitates a canine nasal concha is provided in the air cavity (4) above the air intake section (5).
2. A nitrogen oxygen sensor according to claim 1, characterized in that: The air cavity (4) is composed of a front cavity (41), a middle cavity (42) and a rear cavity (43), the cross-sectional areas of the front cavity (41), the middle cavity (42) and the rear cavity (43) increasing in sequence, the front cavity (41) being connected to the air intake section (5), the bionic flow guide structure being installed in the front cavity (41), and the rear cavity (43) being connected to the inner cavity of the housing (1).
3. A nitrogen oxygen sensor according to claim 2, characterized in that: The diameter of the front cavity (41) is 9 to 11 mm; the diameter of the middle cavity (42) is 15 to 17 mm; and the diameter of the rear cavity (43) is 17 to 19 mm.
4. A nitrogen oxygen sensor according to claim 1, characterized in that: The air intake section (5) is composed of a cylindrical section (51) having a diameter smaller than that of the front cavity (41) and a connecting section (52), and a plurality of air intake holes (7) are provided on the cylindrical section (51) and the connecting section (52).
5. A nitrogen oxygen sensor according to claim 2, characterized in that: The bionic flow guide structure comprises a plurality of flow guide plates (6); one ends of the plurality of flow guide plates (6) are connected to each other to form a connection point that is consistent with the axis of the front cavity (41); the other ends of the flow guide plates (6) are connected to the inner wall of the front cavity (41).
6. A nitrogen oxygen sensor according to claim 5, characterized in that: Three guide plates (6) are provided, and the three guide plates (6) are evenly distributed in the front cavity (41) to divide the front cavity (41) into three sub-cavities, and the areas of the air inlet holes (7) mapped in the three sub-cavities are all consistent.
7. A nitrogen oxygen sensor according to claim 2, characterized in that: The probe body (2) extends into the middle cavity (42).
8. A method for controlling the working temperature of a nitrogen oxygen sensor according to any one of claims 1 to 7, characterized in that: The real-time working temperature of the nitrogen oxide sensor is obtained, and historical data is traversed according to the real-time working temperature to query and predict the working condition change of the nitrogen oxide sensor from the historical data, and the heating data of the nitrogen oxide sensor is adjusted according to the working condition change, and then the nitrogen oxide sensor is preheated; it is judged whether the temperature of the nitrogen oxide sensor reaches a preset value of the preheating temperature, if not, the temperature of the nitrogen oxide sensor is heated to the preset value through PID closed-loop control, if reached, the temperature of the nitrogen oxide sensor is controlled to be maintained at the preset value, and when the internal combustion engine releases exhaust gas, the temperature of the nitrogen oxide sensor is maintained at the preset value with a calibrated heating power according to the exhaust gas temperature of the exhaust gas.
9. A self-diagnosis method based on a nitrogen oxide sensor according to any one of claims 1 to 7, characterized in that: The limiting current Ip1 in the first chamber detection chamber of the nitrogen oxide sensor is obtained, and the limiting current Ip1 is compared with a preset range. If the limiting current Ip1 exceeds the preset range, the pump oxygen voltage of the nitrogen oxide sensor is calibrated through PID closed-loop control, and if the limiting current Ip1 still exceeds the preset range after a set number of calibrations, the operating data of the nitrogen oxide sensor is recorded as fault information, and a fault report is sent; if the limiting current Ip1 is within the preset range, it indicates that the nitrogen oxide sensor is operating normally.