Nitrogen oxide sensor chip, nitrogen oxide sensor assembly, and vehicle
By setting up a decomposition chamber and a detection chamber inside the nitrogen oxide sensor chip and coating it with a porous catalyst coating, the problem of inaccurate detection caused by the cross-sensitivity of ammonia gas was solved, and accurate detection and rapid assembly of nitrogen oxides in exhaust gas were achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- CHINA FAW CO LTD
- Filing Date
- 2025-06-24
- Publication Date
- 2026-07-21
AI Technical Summary
Existing nitrogen oxide sensors suffer from inaccurate detection due to cross-sensitivity to ammonia in exhaust gas, and improper catalyst coating thickness can affect sensor reaction time or result in insufficient processing.
A decomposition chamber and a detection chamber are set inside the nitrogen oxide sensor chip. The inner wall is coated with a porous catalyst coating. The exhaust gas and ammonia are catalytically decomposed into nitrogen and water in the decomposition chamber and accurately detected through the detection chamber.
It achieves accurate detection of nitrogen oxides by reducing the influence of ammonia on detection, simplifies the assembly process, and improves reaction speed and accuracy.
Smart Images
Figure CN224535882U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of automotive sensor technology, and in particular to a nitrogen oxide sensor chip, a nitrogen oxide sensor assembly, and a vehicle. Background Technology
[0002] In exhaust emission treatment systems, Selective Catalytic Reduction (SCR) is a core technology for reducing nitrogen oxides in exhaust gases. It reduces nitrogen oxides to nitrogen and water vapor by injecting urea into the exhaust gas under high temperature and the action of a catalyst. In this technology, a nitrogen oxide sensor detects the concentration of nitrogen oxides in the exhaust gas at the system input to control the amount of urea injected into the system. The same nitrogen oxide sensor is also used to detect whether the nitrogen oxide emission concentration at the system output meets the standards.
[0003] In actual processing, because ammonia can affect the nitrogen oxide sensor, in order to accurately control the amount of urea injected and improve the concentration detection of the sensor, an ammonia oxidation catalyst is coated on the outside of the nitrogen oxide sensor before the exhaust gas is detected after the system has finished treating it. This allows the ammonia to be converted into nitrogen and water, reducing its impact on the sensor.
[0004] However, coating the outside of the nitrogen oxide sensor with an oxidation catalyst can have a problem. If the coating is too thick, it may affect the sensor's reaction time. If the coating is too thin, it may lead to insufficient ammonia treatment, which will affect the nitrogen oxide sensor. Utility Model Content
[0005] The purpose of this utility model is to provide a nitrogen oxide sensor chip, a nitrogen oxide sensor assembly, and a vehicle, so as to solve one or more technical problems existing in the prior art, and at least provide a beneficial option or create conditions.
[0006] The solution to the technical problem of this utility model is:
[0007] In a first aspect, this application provides a nitrogen oxide sensor chip, comprising:
[0008] The substrate has an air inlet on its surface. The substrate has a decomposition chamber and a detection chamber inside. The air inlet, the decomposition chamber and the detection chamber are connected in sequence. The inner wall of the decomposition chamber is coated with a porous catalyst coating. The detection chamber is equipped with a detection electrode.
[0009] This technical solution has at least the following beneficial effects: After the exhaust gas is introduced into the emission treatment system, the exhaust gas and ammonia enter the substrate of the nitrogen oxide sensor core through the inlet. After entering the decomposition chamber, the exhaust gas and ammonia can enter the porous catalyst coating. Then, the ammonia reacts with the catalyst on the porous catalyst coating, causing the ammonia to be catalytically decomposed into nitrogen and water. After the ammonia is fully decomposed in the decomposition chamber, the concentration of ammonia in the mixed gas is greatly reduced. At this time, the gas that has entered the nitrogen oxide sensor core enters the detection chamber. After the detection electrode catalytically decomposes oxygen at high temperature, it is pumped out and outputs a current value, thereby realizing the accurate detection of nitrogen oxides in the exhaust gas.
[0010] This solution, by setting a decomposition chamber inside the nitrogen oxide sensor chip that communicates with the detection chamber, compared to coating the nitrogen oxide sensor chip with a catalyst on the outside, does not affect the installation of the nitrogen oxide chip and provides more space to set a porous catalyst coating with sufficient thickness according to different situations. At the same time, it does not require a large number of information samples as experimental data and can be quickly assembled and applied.
[0011] As a further improvement to the above technical solution, the thickness of the porous catalyst coating is h, wherein 10μm≤h≤600μm.
[0012] As a further improvement to the above technical solution, the porosity of the porous catalyst coating is 10%-40%.
[0013] As a further improvement to the above technical solution, a first channel for connecting the decomposition chamber and the detection chamber is provided in the matrix, wherein the cross-sectional area of the first channel is smaller than the cross-sectional area of the decomposition chamber and the cross-sectional area of the detection chamber are both smaller.
[0014] As a further improvement to the above technical solution, a first gas diffusion barrier is provided in the first channel, and a catalyst is provided on the first gas diffusion barrier.
[0015] As a further improvement to the above technical solution, the cross-sectional area of the air inlet is smaller than the cross-sectional area of the decomposition chamber.
[0016] As a further improvement to the above technical solution, a second gas diffusion barrier is provided inside the air inlet, and a catalyst is provided on the second gas diffusion barrier.
[0017] As a further improvement to the above technical solution, the substrate is provided with at least two detection chambers, and the at least two detection chambers are sequentially connected to each other through a second channel.
[0018] Secondly, this application also provides a nitrogen oxide sensor assembly, which includes a nitrogen oxide sensor chip provided in the first aspect.
[0019] Thirdly, this application also provides a vehicle that includes a nitrogen oxide sensor chip provided in the first aspect. Attached Figure Description
[0020] To more clearly illustrate the technical solutions in the embodiments of this utility model, the accompanying drawings used in the description of the embodiments will be briefly explained below. Obviously, the described drawings are only a part of the embodiments of this utility model, and not all of them. Those skilled in the art can obtain other design schemes and drawings based on these drawings without creative effort.
[0021] Figure 1 This is a cross-sectional view of the nitrogen oxide sensor chip of this utility model. Detailed Implementation
[0022] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.
[0023] In the description of this utility model, it should be understood that the directional descriptions, such as up, down, front, back, left, right, etc., indicate the directional or positional relationship based on the directional or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.
[0024] In the description of this utility model, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. If "first" or "second" is used in the description, it is only for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.
[0025] In the description of this utility model, unless otherwise explicitly defined, terms such as "setting," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this utility model in conjunction with the specific content of the technical solution.
[0026] In automotive exhaust treatment systems, selective catalytic reduction (SCR) technology is a core technology for reducing nitrogen oxide (NOx) content. It involves injecting a reducing agent (typically a urea solution) into the exhaust gas, producing ammonia under high-temperature conditions. With the aid of a catalyst, the ammonia mixes with the NOx in the exhaust gas, reducing the NOx to harmless ammonia and water vapor, thus meeting exhaust emission standards. In SCR systems, the NOx concentration is detected by a NOx sensor. This sensor measures the NOx concentration at the system input to determine the amount of urea injected, and also detects the NOx concentration in the exhaust gas at the system output, ensuring that the output exhaust gas meets national standards.
[0027] However, due to the cross-sensitivity of nitrogen oxide sensors to ammonia, the nitrogen oxide concentration detected by the nitrogen oxide sensors is easily inaccurate. There are two existing solutions to eliminate the sensing error of nitrogen oxide sensors caused by ammonia.
[0028] The first method involves optimizing the measured NOx concentration using control models and algorithms to easily distinguish the concentrations of ammonia and nitrogen oxides in the exhaust gas. The second method involves coating the outer surface of the nitrogen oxide sensor's intake section with a highly N2-selective ammonia catalyst. Before the mixture of ammonia and exhaust gas enters the nitrogen oxide sensor, the catalyst converts ammonia into nitrogen and water vapor, reducing the impact of ammonia on the nitrogen oxide sensor.
[0029] However, the first method has a complex control model and requires a large number of information samples, making it unsuitable for rapid development and application. The second method, although simple in principle and effective, only places the catalyst at the head of the nitrogen and oxygen sensor chip. If the catalyst layer is too thick, it will affect the response time of the nitrogen and oxygen sensor. If the catalyst layer is too thin, there will be problems such as insufficient ammonia treatment.
[0030] Therefore, this application provides a nitrogen oxide sensor chip, a nitrogen oxide sensor assembly, and a vehicle that can solve the above problems.
[0031] Firstly, referring to Figure 1This application provides a nitrogen oxide sensor chip, which includes a substrate 100, an air inlet 110 on the surface of the substrate 100, a decomposition chamber 200 and a detection chamber 300 inside the substrate 100, the air inlet 110, the decomposition chamber 200 and the detection chamber 300 being connected in sequence, the inner wall of the substrate 100 at the decomposition chamber 200 being coated with a porous catalyst coating 210, the catalyst in the porous catalyst coating 210 being able to react with ammonia gas at high temperature, so that ammonia gas is converted into nitrogen gas and water, and a detection electrode is provided in the detection chamber 300. Specifically, the detection electrode is able to catalytically decompose oxygen at high temperature, pump out and output current value, so as to realize the detection of oxygen and nitrogen oxide gases.
[0032] As described above, after the exhaust gas is introduced into the emission treatment system, the exhaust gas and ammonia enter the substrate 100 of the nitrogen oxide sensor core through the inlet 110. After entering the decomposition chamber 200, the exhaust gas and ammonia can enter the porous catalyst coating 210. Then, the ammonia reacts with the catalyst on the porous catalyst coating 210, causing the ammonia to be catalytically decomposed into nitrogen and water. After the ammonia is fully decomposed in the decomposition chamber 200, the concentration of ammonia in the mixed gas is greatly reduced. At this time, the gas entering the nitrogen oxide sensor core enters the detection chamber 300. After the oxygen is catalytically decomposed by the detection electrode at high temperature, the current value is pumped out and output, thereby realizing the accurate detection of nitrogen oxides in the exhaust gas.
[0033] Compared with existing technologies, this solution sets up a decomposition chamber 200 inside the nitrogen oxide sensor chip that is connected to the detection chamber 300. Compared with coating the nitrogen oxide sensor chip with a catalyst on the outside, this solution does not affect the installation of the nitrogen oxide chip and provides more space to set up a porous catalyst coating 210 with sufficient thickness according to different situations. At the same time, it does not require a large number of information samples as experimental data and can be quickly assembled and applied.
[0034] As a further embodiment, in this example, the thickness of the porous catalyst coating 210 is h, wherein 10μm≤h≤600μm. As mentioned above, when the porous catalyst coating 210 is too thick, it affects the flow of gas in the decomposition chamber 200, thereby reducing the reaction rate of the nitrogen oxide sensor chip. When the porous catalyst coating 210 is too thin, it will reduce the full reaction of ammonia. Therefore, the thickness of the porous catalyst coating 210 is limited to between 10μm and 600μm so that the gas can fully react with the catalyst provided on the porous catalyst coating 210 when it passes through the porous catalyst coating 210.
[0035] It should be noted that the thickness direction of the porous catalyst coating 210 is the direction in which the porous catalyst coating 210 is away from the inner wall of the decomposition chamber 200. The height of the porous catalyst coating 210 can be controlled according to the requirements to better convert ammonia.
[0036] As a further embodiment, the porosity of the porous catalyst coating 210 is 10%-40%. Through multiple experiments, the porosity of the porous catalyst coating 210 is controlled. When the porosity is within this preferred range, the flow rate of the gas in the porous catalyst coating 210 is controlled, which allows the ammonia gas to have sufficient time to react with the catalyst, and also allows the gas to quickly pass through the decomposition chamber 200 and enter the detection chamber 300.
[0037] As a further embodiment, a porous catalyst coating 210 is applied to the inner wall of the decomposition chamber 200, allowing heat from outside the nitrogen oxide sensor chip to be better transferred to the porous catalyst coating 210 through the side wall. This facilitates the reaction of ammonia with the catalyst in the porous catalyst coating 210 at a sufficient temperature, thereby improving the conversion rate of ammonia.
[0038] As a further embodiment, the porous catalyst coating 210 is prepared onto the decomposition chamber 200 by screen printing. The screen printing process can effectively control the flatness and thickness of the surface of the porous catalyst coating 210, so that the thickness of the porous catalyst coating 210 is uniform at all parts of the inner wall of the decomposition chamber 200.
[0039] To further control the gas flow rate between the decomposition chamber 200 and the detection chamber 300, a first channel 120 for connecting the decomposition chamber 200 and the detection chamber 300 is provided in the substrate 100. In this embodiment, the cross-sectional area of the first channel 120 is smaller than that of the decomposition chamber 200 and the detection chamber 300. A first gas diffusion barrier 121 is provided in the first channel 120. Through the above technical solution, a first channel 120 with a smaller aperture is provided between the decomposition chamber 200 and the detection chamber 300, and a first gas diffusion barrier 121 that can control the gas diffusion rate is provided in the first channel 120. This can effectively control the movement rate of the exhaust gas and ammonia mixture from the decomposition chamber 200 to the detection chamber 300, so that the ammonia in the mixture reacts fully with the catalyst in the decomposition chamber 200, thereby reducing the concentration of ammonia in the mixture.
[0040] As a further embodiment of the above embodiments, the porosity of the first gas diffusion barrier 121 is 30%-60%. Through multiple experiments, a suitable porosity range for the first gas diffusion barrier 121 is obtained, so that the mixed gas is introduced into the decomposition chamber 200 at an appropriate rate, allowing the ammonia in the decomposition chamber 200 sufficient time to react and improving the ammonia conversion rate.
[0041] Specifically, the first gas diffusion barrier 121 is provided with a catalyst that can react with ammonia gas inside or on its surface. When the mixed gas passes through the first gas diffusion barrier 121, it can fully react with the catalyst inside the first gas diffusion barrier 121 and work synchronously with the porous catalyst coating 210 in the decomposition chamber 200 to decompose ammonia gas more fully.
[0042] To further improve the efficiency of ammonia to nitrogen conversion, in this embodiment, the cross-sectional area of the inlet 110 is smaller than that of the decomposition chamber 200. A second gas diffusion barrier 111 is provided inside the inlet 110, and a catalyst is provided inside the second gas diffusion barrier 111. In this way, the ammonia can be reacted multiple times through the catalyst at the inlet 110, the catalyst in the porous catalyst coating 210 in the decomposition chamber 200, and the catalyst in the second gas diffusion barrier 111 at the first channel 120, thereby reducing the amount of ammonia entering the detection chamber 300 and effectively improving the accuracy of nitrogen oxide sensor measurements.
[0043] As a further embodiment of the above embodiments, the outer surface of the second gas diffusion barrier 111 abuts against the inner surface of the first channel 120, so that the mixed gas passes through the second gas diffusion barrier 111, allowing the ammonia gas to come into more sufficient contact with the catalyst therein.
[0044] The substrate 100 can be provided with at least two detection chambers 300, and the at least two detection chambers 300 are connected in sequence through a second channel 310. In this embodiment, there are two detection chambers 300 and one second channel 310. The first detection chamber 300 can remove oxygen from the mixed gas, and the second detection chamber 300 is used to detect the concentration of nitrogen oxides in the mixed gas. Through multiple detection chambers 300, the accurate detection of various components in the exhaust gas can be achieved.
[0045] Secondly, this application provides a nitrogen oxide sensor assembly, which includes a nitrogen oxide sensor chip provided in the first aspect. The nitrogen oxide sensor assembly is applied in SCR technology and can eliminate the interference of ammonia in the exhaust gas, accurately detect the nitrogen oxide concentration in the exhaust gas, and thus accurately control the injection amount of urea.
[0046] Thirdly, this application provides a vehicle that includes a nitrogen oxide sensor chip provided in the first aspect. By applying the nitrogen oxide sensor chip provided in the first aspect to the vehicle, the concentration of nitrogen oxides in the exhaust gas can be accurately detected, so that the various components of the exhaust gas emitted by the vehicle are within the regulatory range.
[0047] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to the described embodiments. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention, and these equivalent modifications or substitutions are all included within the scope defined by the claims of this application.
Claims
1. A nitrogen oxide sensor chip, characterized in that, include: A substrate (100) has an air inlet (110) on its surface. The substrate (100) has a decomposition chamber (200) and a detection chamber (300) inside. The air inlet (110), the decomposition chamber (200) and the detection chamber (300) are connected in sequence. The inner wall of the decomposition chamber (200) is provided with a porous catalyst coating (210). The detection chamber (300) is provided with a detection electrode.
2. The nitrogen oxide sensor chip according to claim 1, characterized in that, The thickness of the porous catalyst coating (210) is h, wherein 10μm≤h≤600μm.
3. The nitrogen oxide sensor chip according to claim 1, characterized in that, The porous catalyst coating (210) has a porosity of 10%-40%.
4. The nitrogen oxide sensor chip according to claim 1, characterized in that, The substrate (100) has a first channel (120) for connecting the decomposition chamber (200) and the detection chamber (300). The cross-sectional area of the first channel (120) is smaller than that of the decomposition chamber (200) and the cross-sectional area of the detection chamber (300).
5. A nitrogen oxide sensor chip according to claim 4, characterized in that, A first gas diffusion barrier (121) is provided in the first channel (120), and a catalyst is provided on the first gas diffusion barrier (121).
6. A nitrogen oxide sensor chip according to claim 4, characterized in that, The cross-sectional area of the air inlet (110) is smaller than the cross-sectional area of the decomposition chamber (200).
7. A nitrogen oxide sensor chip according to claim 6, characterized in that, A second gas diffusion barrier (111) is provided inside the air inlet (110), and a catalyst is provided on the second gas diffusion barrier (111).
8. A nitrogen oxide sensor chip according to claim 1, characterized in that, The substrate (100) is provided with at least two detection chambers (300), and the at least two detection chambers (300) are connected in sequence through a second channel (310).
9. A nitrogen and oxygen sensor assembly, characterized in that, It includes a nitrogen oxide sensor chip as described in any one of claims 1-8.
10. A vehicle, characterized in that, It includes a nitrogen and oxygen sensor assembly as described in claim 9.