WO2016072633A1 - Nitrogen oxide sensor - Google Patents

Nitrogen oxide sensor Download PDF

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Publication number
WO2016072633A1
WO2016072633A1 PCT/KR2015/010893 KR2015010893W WO2016072633A1 WO 2016072633 A1 WO2016072633 A1 WO 2016072633A1 KR 2015010893 W KR2015010893 W KR 2015010893W WO 2016072633 A1 WO2016072633 A1 WO 2016072633A1
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cavity
electrode
nitrogen oxide
oxygen
exhaust gas
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PCT/KR2015/010893
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French (fr)
Korean (ko)
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홍성진
정연수
박길진
오수민
김은지
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주식회사 아모텍
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Publication of WO2016072633A1 publication Critical patent/WO2016072633A1/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/26—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
    • G01N27/403—Cells and electrode assemblies
    • G01N27/406—Cells and probes with solid electrolytes
    • G01N27/407—Cells and probes with solid electrolytes for investigating or analysing gases
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/26—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
    • G01N27/403—Cells and electrode assemblies
    • G01N27/406—Cells and probes with solid electrolytes
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/26—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
    • G01N27/403—Cells and electrode assemblies
    • G01N27/406—Cells and probes with solid electrolytes
    • G01N27/407—Cells and probes with solid electrolytes for investigating or analysing gases
    • G01N27/4071—Cells and probes with solid electrolytes for investigating or analysing gases using sensor elements of laminated structure
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/26—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
    • G01N27/403—Cells and electrode assemblies
    • G01N27/406—Cells and probes with solid electrolytes
    • G01N27/407—Cells and probes with solid electrolytes for investigating or analysing gases
    • G01N27/4073—Composition or fabrication of the solid electrolyte
    • G01N27/4074—Composition or fabrication of the solid electrolyte for detection of gases other than oxygen
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/26—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
    • G01N27/403—Cells and electrode assemblies
    • G01N27/406—Cells and probes with solid electrolytes
    • G01N27/407—Cells and probes with solid electrolytes for investigating or analysing gases
    • G01N27/4075—Composition or fabrication of the electrodes and coatings thereon, e.g. catalysts
    • G01N27/4076—Reference electrodes or reference mixtures
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/26—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
    • G01N27/416—Systems
    • G01N27/417—Systems using cells, i.e. more than one cell and probes with solid electrolytes
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
    • G01N33/0004—Gaseous mixtures, e.g. polluted air
    • G01N33/0009—General constructional details of gas analysers, e.g. portable test equipment
    • G01N33/0027—General constructional details of gas analysers, e.g. portable test equipment concerning the detector
    • G01N33/0036—General constructional details of gas analysers, e.g. portable test equipment concerning the detector specially adapted to detect a particular component
    • G01N33/0037—NOx

Definitions

  • the present invention relates to a nitrogen oxide sensor.
  • Nitrogen oxide gas is represented as NOx including nitrogen monoxide (NO), nitrogen dioxide (NO2), and nitrous oxide (N2O). Nitrogen monoxide accounts for about 80% of nitrogen oxides, and nitrogen monoxide and nitrogen dioxide occupy most of nitrogen oxide gas.
  • Conventional methods for measuring the concentration of nitrogen oxide gas include a method using the equilibrium potential, oxygen current measurement method by NOx gas decomposition, mixed potential method and the like.
  • the electrochemical cell utilizes electromotive force generated in the electrochemical cell by forming a solid nitrate as a sensing electrode in the solid electrolyte and forming a electrode as a noble metal which makes constant ionic activity in the solid electrolyte. Measure the concentration of nitrogen oxides.
  • Oxygen current measurement method by NOx gas decomposition is a method of measuring the nitrogen oxide concentration by measuring the current by the oxygen ion obtained by decomposition of the NOx gas using a pumping cell.
  • a sensing electrode is formed of metal oxide on one surface of a solid electrolyte, and a reference electrode is formed on the other surface of the solid electrolyte to measure a potential difference between the sensing electrode and the reference electrode.
  • the sensing electrode has reactivity with nitrogen oxide and oxygen, but the reference electrode has reactivity with oxygen only, so that the potential difference between the sensing electrode and the reference electrode is generated according to the concentration of nitrogen oxide contained in the gas. Measure the concentration.
  • the conventional nitrogen oxide sensor has a complicated structure, the manufacturing cost increases, and the measurement sensitivity is not accurate.
  • An object of the present invention is to provide a nitrogen oxide sensor that can reduce the manufacturing cost because the measurement sensitivity is precise and the structure is simple.
  • the present invention provides a solid electrolyte layer, a first diffusion passage positioned at one end of the solid electrolyte layer to allow external exhaust gas to flow therein, the first diffusion passage being in communication with the first diffusion passage.
  • a first pumping electrode comprising a first cavity for controlling the partial pressure of oxygen in the exhaust gas passed, an inner pumping electrode formed in the first cavity and an outer pumping electrode formed at a position different from the first cavity.
  • a second cavity which decomposes nitrogen oxide passing through the first cavity into nitrogen and oxygen ions, a detection electrode formed in the second cavity, and an air formed at a position different from the second cavity, and whose one end is in communication with the atmosphere;
  • a reference electrode installed inside the duct, by controlling the voltage between the detection electrode and the outer pumping electrode to remove oxygen in the exhaust gas, the detection
  • a nitrogen oxide sensor for controlling the voltage between the ground electrode and the reference electrode to measure the concentration of nitrogen oxide from the current generated by moving the oxygen ions to the detection electrode.
  • a reducing agent may be included in the first diffusion passage to reduce nitrogen dioxide to nitrogen monoxide.
  • the solid electrolyte layer may include a heater located inside.
  • the first diffusion passage may be made of a porous solid electrolyte.
  • the second pumping electrode may include a first electrode installed at one side of the first cavity to remove oxygen, and a second electrode installed at the other side of the first cavity and connected to the first electrode.
  • the oxygen between the exhaust gas and the external pumping electrode may be controlled.
  • one end may include a second diffusion passage connected to the first cavity and the other end connected to the second cavity to lead the exhaust gas passing through the first cavity to the second cavity under a predetermined diffusion resistance.
  • the solid electrolyte layer may be formed of a plurality of substrate layers.
  • the nitrogen oxide sensor according to an embodiment of the present invention can pump and detect oxygen with a time difference in the detection electrode, thereby making it possible to precisely measure the measurement sensitivity.
  • the nitrogen oxide sensor according to an embodiment of the present invention can be pumped and detected by the oxygen detection electrode can reduce the manufacturing cost by simplifying the structure.
  • FIG. 1 is a plan view of a nitrogen oxide sensor according to an embodiment of the present invention.
  • FIG. 2 is a cross-sectional view taken along the line A-A in FIG.
  • FIG. 3 is a cross-sectional view showing a modification of the cross section taken along the line A-A in FIG.
  • the nitrogen oxide sensor 1 may include a first diffusion passage 5, a first cavity 7, a first pumping electrode 15, and a second diffusion.
  • the passage 9, the second cavity 11, the detection electrode 21, the reference electrode 23, the solid electrolyte layer 3, the heater part 27, and the air duct 13 may be included.
  • the nitrogen oxide sensor 1 can pump and detect oxygen at a time difference from the detection electrode, thereby making it possible to precisely measure the measurement sensitivity and reduce the manufacturing cost by simplifying the structure.
  • the solid electrolyte layer 3 may have a flat rectangular structure in which one layer or a plurality of substrate layers 3a to 3f are stacked in this order.
  • the solid electrolyte layer 3 is a dense hermetic oxygen ion conductive material
  • the fifth substrate layer 3e and the sixth substrate layer 3f may be stacked, but are not limited thereto.
  • the solid electrolyte layer 3 may be formed by using an oxygen ion conductive solid electrolyte such as zirconium oxide, and may be manufactured by integrally sintering a laminate of the solid electrolyte layer.
  • Oxygen is pumped through the solid electrolyte layer 3 because the electrolyte can be conducted to oxide ions.
  • the solid electrolyte layer 3 is not shown between the layers, the insulating layer is laminated so that it is not modified by electricity or heat.
  • the first diffusion passage 5 is the first substrate passage 3 where the exhaust gas passes first, as shown in FIG. 3 on the left side of one end of the solid electrolyte layer. It may be located at the left end of, but is not limited thereto.
  • one end of the first diffusion passage 5 is exposed to the outside into which the exhaust gas is introduced, and the other end is in communication with the first cavity 7 to include exhaust gas containing nitrogen oxide under a predetermined diffusion resistance. Gas can be led into the first cavity 7.
  • the first diffusion passage 5 can adjust the detection sensitivity of the nitrogen oxide concentration by changing the cross-sectional area, the shape of the cross section, the length.
  • the first diffusion passage 5 is a porous solid electrolyte to prevent the poisoning substances and the like from flowing into the nitrogen oxide sensor due to the diffusion resistance of the porous body, and reduce the signal nonuniformity due to the pulsation of the exhaust gas. have.
  • the first diffusion passage 5 may have a circular or rectangular cross section and a trumpet shape, but is not limited thereto.
  • the first diffusion passage 5 may be formed by stacking sheets and having pores 5a therein. can do.
  • the first diffusion passage 5 increases the diffusion rate of the exhaust gas, and if the diameter of the pores is small, the diffusion rate of the exhaust gas is decreased according to the diameter of the pores. Can be adjusted.
  • a reducing agent may be included in the first diffusion passage 5 to increase the accuracy of nitrogen oxide concentration measurement.
  • nitrogen dioxide has a larger molecular weight than nitrogen monoxide, the diffusion rate is slow, causing inaccuracy in the measurement of nitrogen oxide concentration, and thus a reducing agent reduces nitrogen dioxide to nitrogen monoxide. Therefore, the reducing agent included in the first diffusion passage 5 may improve the measurement sensitivity of the nitrogen oxide concentration.
  • the first cavity 7 is formed extending in the right direction from one end of the first diffusion passage 5, which is the diffusion direction of the exhaust gas, and the oxygen partial pressure remaining in the exhaust gas passing through the first diffusion passage. Space to adjust.
  • the oxygen partial pressure of the first cavity 7 is controlled by controlling the voltage between the inner pumping electrode and the outer pumping electrode 19 so that the voltage between the inner pumping electrode 17 and the reference electrode 23 becomes a constant value.
  • the partial pressure of oxygen in the exhaust gas flowing into the second cavity 11 is constant.
  • the concentration of oxygen remaining in the exhaust gas may be removed to a predetermined level or less through the first pumping electrode 15.
  • the first pumping electrode 15 may include an inner pumping electrode 17 and an outer pumping electrode 19, and control a voltage for pumping an oxygen component from exhaust gas.
  • the inner pumping electrode 17 and the outer pumping electrode 19 may be connected to each other to form the first pumping electrode 15.
  • the first pumping electrode 15 removes oxygen in the exhaust gas to lower the oxygen partial pressure.
  • the oxygen present in the exhaust gas is not sufficiently removed from the first pumping electrode 15, the oxygen reaches the detection electrode 21 and is ionized to act as noise. Therefore, the concentration of nitrogen oxide can be measured larger than the actual.
  • the inner pumping electrodes 17 are disposed in pairs on the upper and lower sides of the first cavity 7 through which the exhaust gas flows through the first diffusion passage 5. And it may be connected therebetween, but is not limited to this may be disposed only on one side, for example, the upper side or the lower side of the first cavity.
  • the inner pumping electrode 17 may include a first electrode 17a disposed on the upper side of the first cavity 7 and a second electrode 17b disposed on the lower side, and have a rectangular shape. It may be made of a porous cermet electrode.
  • the inner pumping electrode 17 may include a connection electrode 17c connecting between the first electrode 17a and the second electrode 17b.
  • oxygen may be pumped from the first electrode 17a and a current may flow between the second electrode 17b and the outer pumping electrode 19.
  • the outer pumping electrode 19 may correspond to the inner pumping electrode 17, that is, the first electrode 17a or the second electrode 17b, and is installed to be in contact with the upper side of the solid electrolyte layer 3, and has a rectangular cross section. It may be made in a shape.
  • the inner pumping electrode 17 and the outer pumping electrode 19 may be used as a material having low or no reducing ability to nitrogen oxides.
  • a predetermined voltage is applied between the inner pumping electrode 17 and the outer pumping electrode 19 from an external variable power source so that a current flows from the outer pumping electrode 19 in the direction of the inner pumping electrode 17. Oxygen of the cavity 7 can be pumped out.
  • the first pumping electrode 15 pumps oxygen present in the exhaust gas of the first cavity 7 by energizing between the inner pumping electrode 17 and the outer pumping electrode 19, that is, the movement of oxygen ions.
  • the oxygen partial pressure of the gas in the first cavity 7 is lowered.
  • the second diffusion passage 9 is connected to the first cavity so that one end of the gas passing through the first cavity 7 is introduced and the other end thereof is the second cavity 11. In communication with the exhaust gas leads to the second cavity 11 under a predetermined diffusion resistance.
  • the second diffusion passage 5 is a porous solid electrolyte and may prevent the poisoning substance and the like from flowing into the nitrogen oxide sensor due to diffusion resistance of the porous body.
  • the second diffusion passage 9 may have a circular or rectangular cross section, but is not limited thereto.
  • the second diffusion passage 9 may be formed by stacking sheets and may include pores 9a therein.
  • the second diffusion passage 9 increases the diffusion speed of the exhaust gas, and if the diameter of the pores is small, the diffusion speed of the exhaust gas is decreased to decrease the diffusion speed of the exhaust gas according to the diameter of the pores. Can be adjusted.
  • the second diffusion passage 9 can adjust the detection sensitivity of the nitrogen oxide concentration by changing the cross-sectional area, the shape of the cross section, the length.
  • the second cavity 11 extends from the second diffusion passage 9 in the right direction and may have a rectangular or circular cross section, but is not limited thereto. Do not. At this time, the second cavity 11 is a space for fine-adjusting the oxygen partial pressure with respect to the gas passing through the second diffusion passage 9.
  • the detection electrode 21 is a lower surface of the second cavity 11, for example, as shown in FIG. 3, and the fourth substrate layer 3d. It may be installed in contact with the upper side of, but is not limited thereto.
  • the detection electrode 21 may contain a catalyst capable of reducing nitrogen oxides and may be made of a porous cermet electrode.
  • the cermet is a sintered material composed of a combination of ceramics and metal.
  • the detection electrode 21 may secondarily remove oxygen not removed from the first pumping electrode 15. Meanwhile, the oxygen concentration of the second cavity 11 is appropriately controlled by controlling the voltage between the detection electrode 23 and the outer pumping electrode 19 so that the voltage between the detection electrode 23 and the reference electrode 23 becomes a constant value. I can keep it.
  • the detection electrode 23 constantly removes oxygen in the exhaust gas so as to have a low oxygen concentration in which the nitrogen oxide of the second cavity 11 is not decomposed, that is, the nitrogen oxide measurement is not substantially affected.
  • the nitrogen oxide sensor 1 has a voltage between the outer pumping electrode 19 and the inner pumping electrode 17 such that the voltage between the detection electrode 21 and the reference electrode 23 is constant. By controlling the oxygen partial pressure existing in the second cavity 11 to be constant.
  • the oxygen partial pressure may be kept constant by removing oxygen to the extent that the nitrogen oxides are not reduced.
  • the detection electrode 21 includes a nitrogen oxide reduction catalyst so that the nitrogen oxide is decomposed into nitrogen and oxygen. At this time, oxygen is ionized and reaches the reference electrode by the voltage applied between the detection electrode 21 and the reference electrode 23.
  • the concentration of the nitrogen oxide can be measured from the current Ip generated by the movement of oxygen ions. This is because the value of the current Ip changes depending on the concentration of the nitrogen oxides.
  • the nitrogen oxide sensor 1 performs the detection and pumping functions in the detection electrode 21 with a time difference, so that the measurement sensitivity is precise and the structure is simplified, thereby reducing the manufacturing cost. .
  • the reference electrode 23 serves as a reference for oxygen concentration partial pressure measurement, and as shown in FIG. 3, for example, on the upper side of the air duct 13, a fourth substrate. It may be installed in contact with the lower side of the layer (3d), but is not limited thereto.
  • the air duct 13 is located at the right end of the solid electrolyte layer 3, for example, at the right end of the third substrate layer 3c, as shown in FIG. 3. It is a passage through which the reference gas flows independently of the 7 and the second cavity 11. At this time, the air duct 13 is formed extending in the longitudinal direction, one end can be opened and communicate with the atmosphere.
  • the air duct 13 is not shown in a portion in contact with the atmosphere, an opening may be formed, and the air, which is a reference gas, may enter the air duct 13 through the opening.
  • the heater part 27 of the nitrogen oxide sensor 1 may be formed on the lower side of the solid electrolyte layer 3, for example, as shown in FIG. 3. It is provided between the 2 substrate layers 3b, and may be located between the insulating layers 27a on the upper and lower surfaces of the heater section to obtain electrical insulation with the solid electrolyte layer.
  • the heater unit 27 may increase the temperature for the smooth operation of the nitrogen oxide sensor 1 according to an embodiment of the present invention. This is when the solid electrolyte layer 3 is stabilized zirconia, the ion conductivity of oxygen is expressed at a temperature of 350 degrees or more. At this time, the heater unit 27 may transfer heat such that the nitrogen oxide sensor is 350 degrees or more.
  • the nitrogen oxide sensor 1 may pump and detect oxygen at a time difference from the detection electrode 21, thereby making it possible to precisely measure the measurement sensitivity.
  • the structure is simplified to reduce manufacturing costs.
  • the nitrogen oxide sensor according to an embodiment of the present invention can pump and detect oxygen with a time difference in the detection electrode, thereby making it possible to precisely measure the measurement sensitivity.
  • the nitrogen oxide sensor according to an embodiment of the present invention can be pumped and detected by the oxygen detection electrode can reduce the manufacturing cost by simplifying the structure.

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Abstract

A nitrogen oxide sensor is provided. The nitrogen oxide sensor comprises: a solid electrolyte layer; a first diffusion path located at one end of the solid electrolyte layer so as to enable exhaust gas to be introduced from the outside; a first cavity communicating with the first diffusion path so as to control oxygen partial pressure among the exhaust gas having passed through the first diffusion path; a first pumping electrode comprising an inner pumping electrode formed in the first cavity and an outer pumping electrode formed at a location different from that of the first cavity; a second cavity communicating with the first cavity so as to decompose nitrogen oxide having passed through the first cavity into nitrogen and oxygen ions; a detection electrode formed in the second cavity; and a reference electrode formed at a location different from that of the second cavity and provided inside an air duct of which one end communicates with the atmosphere, wherein a voltage between the detection electrode and the outer pumping electrode are controlled such that oxygen is removed from the exhaust gas, and a voltage between the detection electrode and the reference electrode is controlled such that the oxygen ions are moved to the detection electrode, thereby allowing the concentration of nitrogen oxide to be measured from a current generated by the movement of the oxygen ions.

Description

질소 산화물 센서Nitrogen oxide sensor
본 발명은 질소산화물 센서에 관한 것이다.The present invention relates to a nitrogen oxide sensor.
질소 산화물 가스는 일산화질소(NO), 이산화질소(NO2), 아산화질소(N2O)를 포함하여 NOx로서 표시한다. 이 중 일산화질소는 질소산화물의 약 80%를 차지하여, 일산화질소 및 이산화질소가 질소산화물 가스의 대부분을 차지한다. Nitrogen oxide gas is represented as NOx including nitrogen monoxide (NO), nitrogen dioxide (NO2), and nitrous oxide (N2O). Nitrogen monoxide accounts for about 80% of nitrogen oxides, and nitrogen monoxide and nitrogen dioxide occupy most of nitrogen oxide gas.
화석연료에 의한 지구 온난화의 방지를 위해 이산화탄소의 배출량을 억제 하는 것에 대한 요구가 증가하고 있고 이것에 대응하여 연비 또한 향상시킬 필요가 있다. 이러한 요구와 함께 질소산화물 센서에 대한 연구가 증가하고 있다. In order to prevent global warming by fossil fuels, there is an increasing demand for curbing carbon dioxide emissions, and correspondingly, fuel economy needs to be improved. With these demands, research on nitrogen oxide sensors is increasing.
기존의 질소산화물 가스의 농도를 측정하는 방법으로는 평형전위를 이용하는 방법, NOx가스 분해에 의한 산소 전류 측정 방법, 혼합전위 방법 등이 있다.Conventional methods for measuring the concentration of nitrogen oxide gas include a method using the equilibrium potential, oxygen current measurement method by NOx gas decomposition, mixed potential method and the like.
평형 전위를 이용하는 방법에서는 전기 화학적 셀은 고체 전해질에 고체상태의 질산염을 감지전극으로 형성하고 고체 전해질 내의 이온의 활동도를 일정하게 하는 귀금속을 전극으로 형성하여 전기 화학적 셀에서 발생하는 기전력을 이용하여 질소산화물의 농도를 측정한다. In the method using the equilibrium potential, the electrochemical cell utilizes electromotive force generated in the electrochemical cell by forming a solid nitrate as a sensing electrode in the solid electrolyte and forming a electrode as a noble metal which makes constant ionic activity in the solid electrolyte. Measure the concentration of nitrogen oxides.
NOx가스 분해에 의한 산소 전류 측정 방법은 펌핑셀을 이용하여 NOx가스를 분해하여 얻어진 산소이온에 의한 전류를 측정하여 질소산화물 농도를 측정하는 방법이다. Oxygen current measurement method by NOx gas decomposition is a method of measuring the nitrogen oxide concentration by measuring the current by the oxygen ion obtained by decomposition of the NOx gas using a pumping cell.
혼합전위 방법에서는 고체 전해질의 일면에 금속산화물로 감지전극을 형성하고, 고체 전해질의 타면에 기준전극을 형성해 감지전극과 기준전극 사이의 전위차를 측정한다. 이때, 감지전극은 질소산화물과 산소에 대한 반응성을 가지나 기준전극은 산소에만 반응성을 갖고 있어 가스 중에 포함된 질소산화물 농도에 따라 감지전극과 기준전극간의 전위차가 발생하게 되고 이 전위차를 측정함으로써 질소산화물 농도를 측정한다.In the mixed potential method, a sensing electrode is formed of metal oxide on one surface of a solid electrolyte, and a reference electrode is formed on the other surface of the solid electrolyte to measure a potential difference between the sensing electrode and the reference electrode. At this time, the sensing electrode has reactivity with nitrogen oxide and oxygen, but the reference electrode has reactivity with oxygen only, so that the potential difference between the sensing electrode and the reference electrode is generated according to the concentration of nitrogen oxide contained in the gas. Measure the concentration.
그런데, 종래의 질소 산화물 센서는 구조가 복잡하여 제조 비용이 증가하고, 측정 감도가 정밀하지 못한 문제가 발생한다.By the way, the conventional nitrogen oxide sensor has a complicated structure, the manufacturing cost increases, and the measurement sensitivity is not accurate.
본 발명은 측정 감도가 정밀하고 구조가 간소하여 제조 비용을 절감할 수 있는 질소산화물 센서를 제공하는데 목적이 있다.An object of the present invention is to provide a nitrogen oxide sensor that can reduce the manufacturing cost because the measurement sensitivity is precise and the structure is simple.
상술한 과제를 해결하기 위하여 본 발명은 고체전해질 층, 상기 고체전해질 층의 일단에 위치하여 외부의 배기가스가 유입되도록 하는 제1 확산통로, 상기 제1 확산통로와 연통되어 상기 제1 확산통로를 통과한 배기가스 중 산소 분압을 제어하는 제1 캐비티, 상기 제1 캐비티에 형성된 내측 펌핑 전극 및 상기 제1 캐비티와 다른 위치에 형성된 외측 펌핑 전극을 포함하는, 제1 펌핑 전극, 상기 제1 캐비티에 연통되어 상기 제1 캐비티를 통과한 질소산화물을 질소와 산소 이온으로 분해시키는 제2 캐비티, 상기 제2 캐비티에 형성된 검지전극 및 상기 제2 캐비티와 다른 위치에 형성되고, 일단부가 대기와 연통된 에어덕트 내부에 설치되는 기준전극을 포함하여, 상기 검지전극과 외측 펌핑 전극 사이의 전압을 제어하여 배기가스 중 산소를 제거하고, 상기 검지 전극과 기준전극 사이의 전압을 제어하여 상기 산소 이온을 상기 검지전극으로 이동시킴으로써 발생되는 전류로부터 질소산화물의 농도를 측정하는 질소산화물 센서를 제공한다. In order to solve the above problems, the present invention provides a solid electrolyte layer, a first diffusion passage positioned at one end of the solid electrolyte layer to allow external exhaust gas to flow therein, the first diffusion passage being in communication with the first diffusion passage. A first pumping electrode, comprising a first cavity for controlling the partial pressure of oxygen in the exhaust gas passed, an inner pumping electrode formed in the first cavity and an outer pumping electrode formed at a position different from the first cavity. A second cavity which decomposes nitrogen oxide passing through the first cavity into nitrogen and oxygen ions, a detection electrode formed in the second cavity, and an air formed at a position different from the second cavity, and whose one end is in communication with the atmosphere; Including a reference electrode installed inside the duct, by controlling the voltage between the detection electrode and the outer pumping electrode to remove oxygen in the exhaust gas, the detection Provided is a nitrogen oxide sensor for controlling the voltage between the ground electrode and the reference electrode to measure the concentration of nitrogen oxide from the current generated by moving the oxygen ions to the detection electrode.
또한, 상기 제1 확산통로 내부에는 환원제가 포함되어 이산화질소를 일산화질소로 환원시킬 수 있다.In addition, a reducing agent may be included in the first diffusion passage to reduce nitrogen dioxide to nitrogen monoxide.
또한, 상기 고체전해질 층 내부에 위치된 히터부를 포함할 수 있다.In addition, the solid electrolyte layer may include a heater located inside.
또한, 상기 제1 확산통로는 다공질의 고체 전해질로 이루어질 수 있다.In addition, the first diffusion passage may be made of a porous solid electrolyte.
또한, 상기 내측 펌핑 전극은 제1 캐비티의 일측에 설치되어 산소를 제거하도록 하는 제1 전극 및 상기 제1 캐비티의 타측에 설치되고, 상기 제1 전극과 연결된 제2 전극을 포함하여 상기 제2 전극과 외측 펌핑 전극 사이의 전압을 제어하여 배기가스 중 산소를 제거시킬 수 있다.The second pumping electrode may include a first electrode installed at one side of the first cavity to remove oxygen, and a second electrode installed at the other side of the first cavity and connected to the first electrode. The oxygen between the exhaust gas and the external pumping electrode may be controlled.
또한, 일단은 상기 제1 캐비티와 연결되고 타단은 상기 제2 캐비티와 연결되어 상기 제1 캐비티를 통과한 배기가스를 소정의 확산 저항아래에서 상기 제2 캐비티로 이끄는 제2 확산통로를 포함할 수 있다.In addition, one end may include a second diffusion passage connected to the first cavity and the other end connected to the second cavity to lead the exhaust gas passing through the first cavity to the second cavity under a predetermined diffusion resistance. have.
또한, 상기 고체전해질 층은 복수개의 기판층으로 이루어질 수 있다. In addition, the solid electrolyte layer may be formed of a plurality of substrate layers.
본 발명의 일 실시예에 따른 질소 산화물 센서는 검지 전극에서 시간차를 두고 산소의 펌핑과 검지를 할 수 있어 측정 감도를 정밀하게 할 수 있다.The nitrogen oxide sensor according to an embodiment of the present invention can pump and detect oxygen with a time difference in the detection electrode, thereby making it possible to precisely measure the measurement sensitivity.
또한, 본 발명의 일 실시예에 따른 질소 산화물 센서는 검지 전극에서 산소 펌핑과 검지를 할 수 있어 구조가 간소화 되어 제조 원가를 절감할 수 있다. In addition, the nitrogen oxide sensor according to an embodiment of the present invention can be pumped and detected by the oxygen detection electrode can reduce the manufacturing cost by simplifying the structure.
도 1은 본 발명의 일 실시예에 따른 질소 산화물 센서의 평면도이다. 1 is a plan view of a nitrogen oxide sensor according to an embodiment of the present invention.
도 2는 도 1에서 A-A선의 단면도이다. 2 is a cross-sectional view taken along the line A-A in FIG.
도 3은 도 1에서 A-A선의 단면의 변형예를 도시한 단면도이다.3 is a cross-sectional view showing a modification of the cross section taken along the line A-A in FIG.
이하, 첨부한 도면을 참고로 하여 본 발명의 실시예에 대하여 본 발명이 속하는 기술분야에서 통상의 지식을 가진 자가 용이하게 실시할 수 있도록 상세히 설명한다. 본 발명은 여러 가지 상이한 형태로 구현될 수 있으며 여기에서 설명하는 실시예에 한정되지 않는다. 도면에서 본 발명을 명확하게 설명하기 위해서 설명과 관계없는 부분은 생략하였으며, 명세서 전체를 통하여 동일 또는 유사한 구성요소에 대해서는 동일한 참조부호를 붙였다.Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like elements throughout the specification.
본 명세서에서, "포함하다" 또는 "가지다" 등의 용어는 명세서상에 기재된 특징, 숫자, 단계, 동작, 구성 요소, 부품 또는 이들을 조합한 것이 존재함을 지정하려는 것이지, 하나 또는 그 이상의 다른 특징들이나 숫자, 단계, 동작, 구성 요소, 부분품 또는 이들을 조합한 것들의 존재 또는 부가 가능성을 미리 배제하지 않는 것으로 이해되어야 한다. 또한, 층, 막, 영역, 판 등의 부분이 다른 부분 "위에" 있다고 할 경우, 이는 다른 부분 "바로 위에" 있는 경우뿐만 아니라 그 중간에 또 다른 부분이 있는 경우도 포함한다. 반대로 층, 막, 영역, 판 등의 부분이 다른 부분 "아래에" 있다고 할 경우, 이는 다른 부분 "바로 아래에" 있는 경우뿐만 아니라 그 중간에 또 다른 부분이 있는 경우도 포함한다.In this specification, terms such as "comprise" or "have" are intended to indicate that there is a feature, number, step, action, component, part, or combination thereof described on the specification, and one or more other features. It is to be understood that the present invention does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, parts, or combinations thereof. In addition, when a part such as a layer, film, region, plate, etc. is said to be "on" another part, this includes not only when the other part is "right on" but also another part in the middle. Conversely, when a part such as a layer, film, region, plate, etc. is "below" another part, this includes not only the other part "below" but also another part in the middle.
도 1 및 도 2를 참조하면, 본 발명의 일 실시예에 따른 질소산화물 센서(1)는 제1 확산통로(5), 제1 캐비티(7), 제1 펌핑 전극(15), 제2 확산통로(9), 제2 캐비티(11), 검지 전극(21), 기준 전극(23), 고체전해질 층(3), 히터부(27), 에어 덕트(13)를 포함할 수 있다.1 and 2, the nitrogen oxide sensor 1 according to an exemplary embodiment of the present invention may include a first diffusion passage 5, a first cavity 7, a first pumping electrode 15, and a second diffusion. The passage 9, the second cavity 11, the detection electrode 21, the reference electrode 23, the solid electrolyte layer 3, the heater part 27, and the air duct 13 may be included.
본 발명의 일 실시예에 따른 질소산화물 센서(1)는 검지 전극에서 시간차를 두고 산소의 펌핑과 검지를 할 수 있어 측정 감도를 정밀하게 할 수 있고 구조가 간소화 되어 제조 원가를 절감할 수 있다The nitrogen oxide sensor 1 according to an embodiment of the present invention can pump and detect oxygen at a time difference from the detection electrode, thereby making it possible to precisely measure the measurement sensitivity and reduce the manufacturing cost by simplifying the structure.
도 1 내지 도 3을 참조하면, 고체전해질 층(3)은 평판 형상의 직사각형 구조로 한 개의 층 또는 복수개의 기판층(3a~3f)이 순서대로 적층되어 이루어질 수 있다. 1 to 3, the solid electrolyte layer 3 may have a flat rectangular structure in which one layer or a plurality of substrate layers 3a to 3f are stacked in this order.
또한, 고체전해질 층(3)은 치밀한 기밀의 산소이온 전도성 재질로서 제1 기판층(3a), 제2 기판층(3b), 제3 기판층(3c), 제4 기판층(3d), 제5 기판층(3e), 제6 기판층(3f)이 적층될 수 있으나 이에 한정되지는 않는다. In addition, the solid electrolyte layer 3 is a dense hermetic oxygen ion conductive material, the first substrate layer 3a, the second substrate layer 3b, the third substrate layer 3c, the fourth substrate layer 3d, The fifth substrate layer 3e and the sixth substrate layer 3f may be stacked, but are not limited thereto.
이때, 고체전해질 층(3)은 산화 지르코늄 등의 산소이온 전도성의 고체전해질을 이용하여 형성되고 고체 전해질 층의 적층물을 일체로 소결함으로써 제조될 수 있다. In this case, the solid electrolyte layer 3 may be formed by using an oxygen ion conductive solid electrolyte such as zirconium oxide, and may be manufactured by integrally sintering a laminate of the solid electrolyte layer.
산소는 전해질이 산화 이온으로 전도될 수 있기 때문에 고체전해질 층(3)을 통과하여 펌핑된다. 또한, 고체전해질 층(3)은 각 층간에는 도시되지 않았지만 절연층이 적층되어 전기나 열에 의해 변성되지 않도록 한다.Oxygen is pumped through the solid electrolyte layer 3 because the electrolyte can be conducted to oxide ions. In addition, although the solid electrolyte layer 3 is not shown between the layers, the insulating layer is laminated so that it is not modified by electricity or heat.
본 발명의 일 실시예에서 제1 확산통로(5)는 배기가스가 제일 먼저 통과하는 곳으로서 고체 전해질 층의 일단부인 좌측에 예를 들어 도 3에 도시된 바와 같이, 제5 기판층(3e)의 좌측 단부에 위치할 수 있으나 이에 한정되지 않는다. In an embodiment of the present invention, the first diffusion passage 5 is the first substrate passage 3 where the exhaust gas passes first, as shown in FIG. 3 on the left side of one end of the solid electrolyte layer. It may be located at the left end of, but is not limited thereto.
도 1 및 2를 참조하면, 제1 확산통로(5)는 일단은 배기가스가 유입되는 외부에 노출되고 타단은 제1 캐비티(7)와 연통되어 소정의 확산 저항아래에 질소산화물을 포함하는 배기가스를 제1 캐비티(7) 내로 이끌어 넣을 수 있다. 1 and 2, one end of the first diffusion passage 5 is exposed to the outside into which the exhaust gas is introduced, and the other end is in communication with the first cavity 7 to include exhaust gas containing nitrogen oxide under a predetermined diffusion resistance. Gas can be led into the first cavity 7.
이때, 제1 확산 통로(5)는 단면적, 단면의 형상, 길이 등을 변경함으로써 질소산화물 농도의 검출 감도를 조절할 수 있다.At this time, the first diffusion passage 5 can adjust the detection sensitivity of the nitrogen oxide concentration by changing the cross-sectional area, the shape of the cross section, the length.
한편, 제1 확산통로(5)는 다공질의 고체전해질로서 다공질체가 가지는 확산저항에 의해 피독 물질 등이 질소 산화물 센서 내부로 유입되는 것을 방지하고, 배기가스의 맥동으로 인한 신호의 불균일성을 감소시킬 수 있다.On the other hand, the first diffusion passage 5 is a porous solid electrolyte to prevent the poisoning substances and the like from flowing into the nitrogen oxide sensor due to the diffusion resistance of the porous body, and reduce the signal nonuniformity due to the pulsation of the exhaust gas. have.
도 1 및 도 2에 도시된 바와 같이, 제1 확산통로(5)는 단면이 원형 또는 직사각형 및 나팔형상일 수 있으나 이에 한정되지 않고 시트가 적층되어 형성될 수 있으며 내부에는 기공(5a)을 포함할 수 있다. As shown in FIGS. 1 and 2, the first diffusion passage 5 may have a circular or rectangular cross section and a trumpet shape, but is not limited thereto. The first diffusion passage 5 may be formed by stacking sheets and having pores 5a therein. can do.
따라서, 제1 확산통로(5)는 기공(5a)의 지름이 크면 배기가스의 확산속도가 증가하고 기공의 지름이 작으면 배기가스의 확산속도를 감소시켜 기공의 지름에 따라서 배기가스의 확산속도를 조절할 수 있다. Therefore, if the diameter of the pores 5a is large, the first diffusion passage 5 increases the diffusion rate of the exhaust gas, and if the diameter of the pores is small, the diffusion rate of the exhaust gas is decreased according to the diameter of the pores. Can be adjusted.
제1 확산통로(5)의 내부에는 질소산화물 농도측정의 정확성을 높이기 위해서 환원제가 포함될 수 있다. 이때, 이산화질소는 일산화질소에 비해 분자량이 크기 때문에 확산속도가 느려 질소산화물 농도 측정의 부정확성을 야기시키므로 환원제는 이산화질소를 일산화질소로 환원시킨다. 따라서 제1 확산통로(5) 내부에 포함된 환원제는 질소산화물 농도의 측정 감도를 개선시킬 수 있다.A reducing agent may be included in the first diffusion passage 5 to increase the accuracy of nitrogen oxide concentration measurement. At this time, since nitrogen dioxide has a larger molecular weight than nitrogen monoxide, the diffusion rate is slow, causing inaccuracy in the measurement of nitrogen oxide concentration, and thus a reducing agent reduces nitrogen dioxide to nitrogen monoxide. Therefore, the reducing agent included in the first diffusion passage 5 may improve the measurement sensitivity of the nitrogen oxide concentration.
도 2를 참조하면, 제1 캐비티(7)는 배기가스의 확산 방향인 제1 확산통로(5)의 일단에서 우측방향으로 연장되어 형성되고 제1 확산통로를 통과한 배기가스에 잔존하는 산소 분압을 조정하는 공간이다.Referring to FIG. 2, the first cavity 7 is formed extending in the right direction from one end of the first diffusion passage 5, which is the diffusion direction of the exhaust gas, and the oxygen partial pressure remaining in the exhaust gas passing through the first diffusion passage. Space to adjust.
이때, 내측 펌핑 전극(17)과 기준 전극(23) 사이의 전압이 일정한 값이 되도록 내측 펌핑 전극과 외측 펌핑 전극(19) 사이의 전압을 제어함으로써 제1 캐비티(7)의 산소 분압을 제어하여 제2 캐비티(11)에 유입되는 배기가스 중 산소 분압이 일정하도록 한다.At this time, the oxygen partial pressure of the first cavity 7 is controlled by controlling the voltage between the inner pumping electrode and the outer pumping electrode 19 so that the voltage between the inner pumping electrode 17 and the reference electrode 23 becomes a constant value. The partial pressure of oxygen in the exhaust gas flowing into the second cavity 11 is constant.
도 2를 참조하면, 제1 캐비티(7)에서는 제1 펌핑 전극(15)을 통해 배기가스 중 잔존하는 산소의 농도를 일정 수준 이하로 제거할 수 있다. 이때 제1 펌핑 전극(15)은 내측 펌핑 전극(17) 및 외측 펌핑 전극(19)을 포함할 수 있고, 배기가스에서 산소 성분을 펌핑하기 위한 전압을 제어한다. Referring to FIG. 2, in the first cavity 7, the concentration of oxygen remaining in the exhaust gas may be removed to a predetermined level or less through the first pumping electrode 15. In this case, the first pumping electrode 15 may include an inner pumping electrode 17 and an outer pumping electrode 19, and control a voltage for pumping an oxygen component from exhaust gas.
이때, 내측 펌핑 전극(17) 및 외측 펌핑 전극(19)은 서로 접속되어 제1 펌핑 전극(15)을 형성할 수 있다. 제1 펌핑 전극(15)은 배기가스 중 산소를 제거하여 산소 분압을 낮춘다.In this case, the inner pumping electrode 17 and the outer pumping electrode 19 may be connected to each other to form the first pumping electrode 15. The first pumping electrode 15 removes oxygen in the exhaust gas to lower the oxygen partial pressure.
이때, 제1 펌핑 전극(15)에서 배기가스에 존재하는 산소가 충분히 제거되지 못하면 이 산소가 검지 전극(21)에 도달한 후 이온화되어 노이즈로 작용하게 된다. 따라서 질소 산화물의 농도를 실제보다 크게 측정될 수 있다. At this time, when the oxygen present in the exhaust gas is not sufficiently removed from the first pumping electrode 15, the oxygen reaches the detection electrode 21 and is ionized to act as noise. Therefore, the concentration of nitrogen oxide can be measured larger than the actual.
반면, 제1 펌핑 전극(15)에서 배기가스에 존재하는 산소가 과도하게 제거되면 질소 산화물이 내측 펌핑 전극(17) 또는 제2 펌핑 전극(25)에서 환원되어 질소와 산소로 분해되어 노이즈로 작용할 수 있다. On the other hand, when the oxygen present in the exhaust gas is excessively removed from the first pumping electrode 15, the nitrogen oxide is reduced in the inner pumping electrode 17 or the second pumping electrode 25 to be decomposed into nitrogen and oxygen to act as noise. Can be.
도 2를 참조하면, 본 발명의 일 실시예에서 내측 펌핑 전극(17)은 제1 확산통로(5)를 통해 배기가스가 유입되는 제1 캐비티(7)의 상부 및 하부측에 한 쌍으로 배치될 수 있고 그 사이를 연결할 수 있으나 이에 한정되지 않고 제1 캐비티의 일측, 예를 들어 상부측 또는 하부측에만 배치될 수도 있다. Referring to FIG. 2, in one embodiment of the present invention, the inner pumping electrodes 17 are disposed in pairs on the upper and lower sides of the first cavity 7 through which the exhaust gas flows through the first diffusion passage 5. And it may be connected therebetween, but is not limited to this may be disposed only on one side, for example, the upper side or the lower side of the first cavity.
도 2에 도시된 바와 같이, 내측 펌핑 전극(17)은 제1 캐비티(7)의 상부측에 설치된 제1 전극(17a) 및 하부측에 설치된 제2 전극(17b)을 포함할 수 있으며 직사각형 형상의 다공질 서멧 전극으로 이루어질 수 있다. As shown in FIG. 2, the inner pumping electrode 17 may include a first electrode 17a disposed on the upper side of the first cavity 7 and a second electrode 17b disposed on the lower side, and have a rectangular shape. It may be made of a porous cermet electrode.
또한, 본 발명의 일 실시예에서 내측 펌핑 전극(17)은 제1 전극(17a) 및 제2 전극(17b) 사이를 연결하는 연결전극(17c)을 포함할 수 있다. 이때, 일 실시예로서 제1 전극(17a)에서 산소를 펌핑하고 제2 전극(17b)과 외측 펌핑 전극(19) 사이에 전류가 흐르도록 할 수 있다.In addition, in one embodiment of the present invention, the inner pumping electrode 17 may include a connection electrode 17c connecting between the first electrode 17a and the second electrode 17b. In this case, as an embodiment, oxygen may be pumped from the first electrode 17a and a current may flow between the second electrode 17b and the outer pumping electrode 19.
또한 외측 펌핑 전극(19)은 내측 펌핑 전극(17) 즉, 제1 전극(17a) 또는 제2 전극(17b)과 대응할 수 있고 고체 전해질 층(3)의 상측면에 접하게 설치되며, 단면이 직사각형 형상으로 이루어질 수 있다. 이때, 내측 펌핑 전극(17) 및 외측 펌핑 전극(19)은 질소산화물에 대한 환원 능력이 약하거나 없는 재질로 사용될 수 있다.In addition, the outer pumping electrode 19 may correspond to the inner pumping electrode 17, that is, the first electrode 17a or the second electrode 17b, and is installed to be in contact with the upper side of the solid electrolyte layer 3, and has a rectangular cross section. It may be made in a shape. In this case, the inner pumping electrode 17 and the outer pumping electrode 19 may be used as a material having low or no reducing ability to nitrogen oxides.
이때, 내측 펌핑 전극(17) 및 외측 펌핑 전극(19) 간에 외부의 가변 전원에서 소정의 전압을 인가해서 외측 펌핑 전극(19)으로부터 내측 펌핑 전극(17)의 방향으로 전류가 흐르도록 하여 제1 캐비티(7)의 산소를 외부공간으로 퍼낼 수 있다. At this time, a predetermined voltage is applied between the inner pumping electrode 17 and the outer pumping electrode 19 from an external variable power source so that a current flows from the outer pumping electrode 19 in the direction of the inner pumping electrode 17. Oxygen of the cavity 7 can be pumped out.
또한 제1 펌핑 전극(15)은 내측 펌핑 전극(17) 및 외측 펌핑 전극(19)간에 통전에 의해 제1 캐비티(7)의 배기가스에 존재하는 산소를 펌핑하여 즉, 산소 이온의 이동을 가능하게 하여 제1 캐비티(7) 내부에 있는 가스의 산소 분압을 낮춘다. In addition, the first pumping electrode 15 pumps oxygen present in the exhaust gas of the first cavity 7 by energizing between the inner pumping electrode 17 and the outer pumping electrode 19, that is, the movement of oxygen ions. The oxygen partial pressure of the gas in the first cavity 7 is lowered.
도 2를 참조하면, 본 발명의 일 실시예에서 제2 확산통로(9)는 일단은 제1 캐비티(7)를 통과한 가스가 유입되도록 제1 캐비티와 연결되고 타단은 제2 캐비티(11)와 연통되어 배기가스를 소정의 확산 저항아래에서 제2 캐비티(11)로 이끈다. Referring to FIG. 2, in one embodiment of the present invention, the second diffusion passage 9 is connected to the first cavity so that one end of the gas passing through the first cavity 7 is introduced and the other end thereof is the second cavity 11. In communication with the exhaust gas leads to the second cavity 11 under a predetermined diffusion resistance.
도 1 및 도 2를 참조하면, 제2 확산통로(5)는 다공질의 고체전해질로서 다공질체가 가지는 확산저항에 의해 피독 물질 등이 질소 산화물 센서 내부로 유입되는 것을 방지할 수 있다.Referring to FIGS. 1 and 2, the second diffusion passage 5 is a porous solid electrolyte and may prevent the poisoning substance and the like from flowing into the nitrogen oxide sensor due to diffusion resistance of the porous body.
한편, 제2 확산통로(9)는 단면이 원형 또는 직사각형일 수 있으나 이에 한정되지 않고 시트가 적층되어 형성될 수 있으며 내부에는 기공(9a)을 포함할 수 있다. The second diffusion passage 9 may have a circular or rectangular cross section, but is not limited thereto. The second diffusion passage 9 may be formed by stacking sheets and may include pores 9a therein.
따라서, 제2 확산통로(9)는 기공(9a)의 지름이 크면 배기가스의 확산속도가 증가하고 기공의 지름이 작으면 배기가스의 확산속도를 감소시켜 기공의 지름에 따라서 배기가스의 확산속도를 조절할 수 있다. Therefore, if the diameter of the pores 9a is large, the second diffusion passage 9 increases the diffusion speed of the exhaust gas, and if the diameter of the pores is small, the diffusion speed of the exhaust gas is decreased to decrease the diffusion speed of the exhaust gas according to the diameter of the pores. Can be adjusted.
이때, 제2 확산통로(9)는 단면적, 단면의 형상, 길이 등을 변경함으로써, 질소산화물 농도의 검출 감도를 조절할 수 있다.At this time, the second diffusion passage 9 can adjust the detection sensitivity of the nitrogen oxide concentration by changing the cross-sectional area, the shape of the cross section, the length.
도 2 및 도 3을 참조하면, 본 발명의 일 실시예에서 제2 캐비티(11)는 제2 확산통로(9)에서부터 우측 방향으로 연장 형성되고 단면이 직사각형 또는 원형으로 이루어질 수 있으나 이에 한정되지는 않는다. 이때, 제2 캐비티(11)는 제2 확산통로(9)를 통과한 가스에 대하여 산소 분압을 미세 조정하는 공간이다. 2 and 3, in an embodiment of the present invention, the second cavity 11 extends from the second diffusion passage 9 in the right direction and may have a rectangular or circular cross section, but is not limited thereto. Do not. At this time, the second cavity 11 is a space for fine-adjusting the oxygen partial pressure with respect to the gas passing through the second diffusion passage 9.
도 1 내지 도 3을 참조하면, 본 발명의 일 실시예에서 검지 전극(21)은 제2 캐비티(11)의 하측면, 예를 들어 도 3에 도시된 바와 같이, 제4 기판층(3d)의 상측면에 접하게 설치될 수 있으나 이에 한정되지 않는다.1 to 3, in one embodiment of the present invention, the detection electrode 21 is a lower surface of the second cavity 11, for example, as shown in FIG. 3, and the fourth substrate layer 3d. It may be installed in contact with the upper side of, but is not limited thereto.
검지 전극(21)은 질소산화물을 환원할 수 있는 촉매를 함유할 수 있으며 다공질 서멧 전극으로 이루어질 수 있다. 이때, 서멧이란 세라믹스와 금속의 조합으로 구성된 소결재료이다. The detection electrode 21 may contain a catalyst capable of reducing nitrogen oxides and may be made of a porous cermet electrode. At this time, the cermet is a sintered material composed of a combination of ceramics and metal.
도 2를 참조하면, 본 발명의 일 실시예에서 검지 전극(21)은 제1 펌핑 전극(15)에서 제거되지 않은 산소를 2차로 제거할 수 있다. 한편, 검지 전극(23)과 기준 전극(23)사이의 전압이 일정한 값이 되도록 검지 전극(23)과 외측 펌핑 전극(19) 사이에 전압을 제어하여 제2 캐비티(11)의 산소 농도를 적절하게 유지할 수 있다. Referring to FIG. 2, in one embodiment of the present invention, the detection electrode 21 may secondarily remove oxygen not removed from the first pumping electrode 15. Meanwhile, the oxygen concentration of the second cavity 11 is appropriately controlled by controlling the voltage between the detection electrode 23 and the outer pumping electrode 19 so that the voltage between the detection electrode 23 and the reference electrode 23 becomes a constant value. I can keep it.
또한, 검지 전극(23)은 제2 캐비티(11)의 질소산화물이 분해되지 않는 범위 즉, 질소산화물 측정에 실질적인 영향이 없는 낮은 산소 농도가 되도록 일정하게 배기가스 중의 산소를 제거한다. In addition, the detection electrode 23 constantly removes oxygen in the exhaust gas so as to have a low oxygen concentration in which the nitrogen oxide of the second cavity 11 is not decomposed, that is, the nitrogen oxide measurement is not substantially affected.
본 발명의 일 실시예에 따른 질소산화물 센서(1)는 검지 전극(21)과 기준 전극(23)사이의 전압이 일정한 값이 되도록 외측 펌핑 전극(19)과 내측 펌핑 전극(17) 사이의 전압을 제어하여 제2 캐비티(11) 내부에 존재하는 산소 분압이 일정하도록 한다. The nitrogen oxide sensor 1 according to an embodiment of the present invention has a voltage between the outer pumping electrode 19 and the inner pumping electrode 17 such that the voltage between the detection electrode 21 and the reference electrode 23 is constant. By controlling the oxygen partial pressure existing in the second cavity 11 to be constant.
이때, 산소 분압은 질소산화물이 환원되지 않는 범위까지 산소를 제거하여 일정하게 유지할 수 있다. At this time, the oxygen partial pressure may be kept constant by removing oxygen to the extent that the nitrogen oxides are not reduced.
한편, 본 발명의 일 실시예에서 검지 전극(21)은 질소산화물의 환원 촉매를 포함하여 질소산화물이 질소와 산소로 분해가 이루어지도록 한다. 이때 산소는 이온화되어 검지 전극(21)과 기준 전극(23) 사이에 걸린 전압에 의해 기준 전극에 도달한다. On the other hand, in one embodiment of the present invention, the detection electrode 21 includes a nitrogen oxide reduction catalyst so that the nitrogen oxide is decomposed into nitrogen and oxygen. At this time, oxygen is ionized and reaches the reference electrode by the voltage applied between the detection electrode 21 and the reference electrode 23.
이러한 산소 이온의 이동에 의해 발생한 전류(Ip)로부터 질소산화물의 농도를 측정할 수 있다. 이때 전류(Ip)의 값은 질소산화물의 농도에 의존하여 변화하기 때문이다.The concentration of the nitrogen oxide can be measured from the current Ip generated by the movement of oxygen ions. This is because the value of the current Ip changes depending on the concentration of the nitrogen oxides.
이를 통해 본 발명의 일 실시예에 따른 질소산화물 센서(1)는 검지 전극(21)에서 검지와 펌핑 기능을 시간차를 두고 수행함으로써 측정 감도가 정밀해지고 또한 구조가 간소화되어 제조 원가를 절감할 수 있다.As a result, the nitrogen oxide sensor 1 according to the exemplary embodiment of the present invention performs the detection and pumping functions in the detection electrode 21 with a time difference, so that the measurement sensitivity is precise and the structure is simplified, thereby reducing the manufacturing cost. .
도 2를 참조하면, 본 발명의 일 실시예에서 기준 전극(23)은 산소 농도 분압 측정의 기준이 되고, 에어 덕트(13)의 상측면 예를 들어 도 3에 도시된 바와 같이, 제4 기판층(3d)의 하측면에 접하게 설치될 수 있으나 이에 한정되지는 않는다.Referring to FIG. 2, in one embodiment of the present invention, the reference electrode 23 serves as a reference for oxygen concentration partial pressure measurement, and as shown in FIG. 3, for example, on the upper side of the air duct 13, a fourth substrate. It may be installed in contact with the lower side of the layer (3d), but is not limited thereto.
도 2를 참조하면, 에어 덕트(13)는 고체전해질 층(3)의 우측 단부, 예를 들어 도 3에 도시된 바와 같이, 제3 기판층(3c)의 우측 단부에 위치하여, 제1 캐비티(7) 및 제2 캐비티(11)와는 독립적으로 기준 가스가 유입되는 통로이다. 이때, 에어 덕트(13)는 길이방향으로 연장되어 형성되고, 일단부가 개구되어 대기와 연통될 수 있다. Referring to FIG. 2, the air duct 13 is located at the right end of the solid electrolyte layer 3, for example, at the right end of the third substrate layer 3c, as shown in FIG. 3. It is a passage through which the reference gas flows independently of the 7 and the second cavity 11. At this time, the air duct 13 is formed extending in the longitudinal direction, one end can be opened and communicate with the atmosphere.
한편, 에어 덕트(13)는 대기와 접촉하는 부위에 도시되지는 않았으나 개구부가 형성될 수 있고 이 개구부를 통해서 기준 가스인 대기가 에어 덕트(13) 내부로 들어올 수 있다. On the other hand, although the air duct 13 is not shown in a portion in contact with the atmosphere, an opening may be formed, and the air, which is a reference gas, may enter the air duct 13 through the opening.
본 발명의 일 실시예에 따른 질소산화물 센서(1)의 히터부(27)는 고체 전해질 층(3)의 하부 측 예를 들어 도 3에 도시된 바와 같이, 제1 기판층(3a) 및 제2 기판층(3b) 사이에 설치되고, 히터부의 상하면에는 고체 전해질 층과의 전기적 절연을 얻기 위해서 절연층(27a) 사이에 위치할 수 있다. The heater part 27 of the nitrogen oxide sensor 1 according to an embodiment of the present invention may be formed on the lower side of the solid electrolyte layer 3, for example, as shown in FIG. 3. It is provided between the 2 substrate layers 3b, and may be located between the insulating layers 27a on the upper and lower surfaces of the heater section to obtain electrical insulation with the solid electrolyte layer.
이때, 히터부(27)는 본 발명의 일 실시예에 따른 질소산화물 센서(1)가 원활하게 작동하기 위한 온도까지 높일 수 있다. 이는 고체전해질 층(3)이 안정화 지르코니아일 때 산소의 이온 전도성은 350도 이상의 온도에서 발현되는데 이때 히터부(27)는 질소산화물 센서가 350도 이상이 되도록 열을 전달할 수 있다.In this case, the heater unit 27 may increase the temperature for the smooth operation of the nitrogen oxide sensor 1 according to an embodiment of the present invention. This is when the solid electrolyte layer 3 is stabilized zirconia, the ion conductivity of oxygen is expressed at a temperature of 350 degrees or more. At this time, the heater unit 27 may transfer heat such that the nitrogen oxide sensor is 350 degrees or more.
본 발명의 일 실시예에 따른 질소 산화물 센서(1)는 검지 전극(21)에서 시간차를 두고 산소의 펌핑과 검지를 할 수 있어 측정 감도를 정밀하게 할 수 있다. 또한 구조가 간소화 되어 제조 원가를 절감할 수 있다. The nitrogen oxide sensor 1 according to the exemplary embodiment of the present invention may pump and detect oxygen at a time difference from the detection electrode 21, thereby making it possible to precisely measure the measurement sensitivity. In addition, the structure is simplified to reduce manufacturing costs.
이상에서 본 발명의 일 실시예에 대하여 설명하였으나, 본 발명의 사상은 본 명세서에 제시되는 실시 예에 제한되지 아니하며, 본 발명의 사상을 이해하는 당업자는 동일한 사상의 범위 내에서, 구성요소의 부가, 변경, 삭제, 추가 등에 의해서 다른 실시 예를 용이하게 제안할 수 있을 것이나, 이 또한 본 발명의 사상범위 내에 든다고 할 것이다.Although one embodiment of the present invention has been described above, the spirit of the present invention is not limited to the embodiments set forth herein, and those skilled in the art who understand the spirit of the present invention, within the scope of the same idea, the addition of components Other embodiments may be easily proposed by changing, deleting, adding, etc., but this will also be within the scope of the present invention.
본 발명의 일 실시예에 따른 질소 산화물 센서는 검지 전극에서 시간차를 두고 산소의 펌핑과 검지를 할 수 있어 측정 감도를 정밀하게 할 수 있다.The nitrogen oxide sensor according to an embodiment of the present invention can pump and detect oxygen with a time difference in the detection electrode, thereby making it possible to precisely measure the measurement sensitivity.
또한, 본 발명의 일 실시예에 따른 질소 산화물 센서는 검지 전극에서 산소 펌핑과 검지를 할 수 있어 구조가 간소화 되어 제조 원가를 절감할 수 있다. In addition, the nitrogen oxide sensor according to an embodiment of the present invention can be pumped and detected by the oxygen detection electrode can reduce the manufacturing cost by simplifying the structure.

Claims (7)

  1. 고체전해질 층;Solid electrolyte layer;
    상기 고체전해질 층의 일단에 위치하여 외부의 배기가스가 유입되도록 하는 제1 확산통로; A first diffusion passage positioned at one end of the solid electrolyte layer to allow external exhaust gas to flow therein;
    상기 제1 확산통로와 연통되어 상기 제1 확산통로를 통과한 배기가스 중 산소 분압을 제어하는 제1 캐비티;A first cavity communicating with the first diffusion passage and controlling the partial pressure of oxygen in the exhaust gas passing through the first diffusion passage;
    상기 제1 캐비티에 형성된 내측 펌핑 전극 및 상기 제1 캐비티와 다른 공간에 형성된 외측 펌핑 전극을 포함하는 제1 펌핑 전극;A first pumping electrode including an inner pumping electrode formed in the first cavity and an outer pumping electrode formed in a space different from the first cavity;
    상기 제1 캐비티에 연통되어 상기 제1 캐비티를 통과한 질소산화물을 질소와 산소 이온으로 분해시키는 제2 캐비티;A second cavity communicating with the first cavity and decomposing nitrogen oxide passing through the first cavity into nitrogen and oxygen ions;
    상기 제2 캐비티에 형성된 검지전극 및 A detection electrode formed in the second cavity and
    상기 제2 캐비티와 다른 위치에 형성되고, 일단부가 대기와 연통된 에어덕트 내부에 설치되는 기준전극;을 포함하여, And a reference electrode formed at a position different from the second cavity and installed at one end of the air duct in communication with the atmosphere.
    상기 검지전극과 외측 펌핑 전극 사이의 전압을 제어하여 배기가스 중 산소를 제거하고, 상기 검지 전극과 기준전극 사이의 전압을 제어하여 상기 산소 이온을 상기 검지전극으로 이동시킴으로써 발생되는 전류로부터 질소산화물의 농도를 측정하는 질소산화물 센서. The voltage between the detection electrode and the outer pumping electrode is controlled to remove oxygen from the exhaust gas, and the voltage between the detection electrode and the reference electrode is controlled to move the oxygen ions to the detection electrode. Nitrogen oxide sensor to measure the concentration.
  2. 제1 항에 있어서,According to claim 1,
    상기 제1 확산통로 내부에는 환원제가 포함되어 이산화질소를 일산화질소로 환원시키는 질소산화물 센서.A nitrogen oxide sensor that includes a reducing agent inside the first diffusion passage to reduce nitrogen dioxide to nitrogen monoxide.
  3. 제1 항에 있어서,According to claim 1,
    상기 고체전해질 층 내부에 위치된 히터부를 포함하는 질소산화물 센서.A nitrogen oxide sensor comprising a heater unit located inside the solid electrolyte layer.
  4. 제1 항에 있어서,According to claim 1,
    제1 확산통로는 다공질의 고체 전해질로 이루어진 질소산화물 센서.The first diffusion passage is a nitrogen oxide sensor consisting of a porous solid electrolyte.
  5. 제1 항 내지 제 4 항 중 어느 한 항에 있어서,The method according to any one of claims 1 to 4,
    상기 내측 펌핑 전극은 제1 캐비티의 일측에 설치되어 산소를 제거하도록 하는 제1 전극 및 상기 제1 캐비티의 타측에 설치되고, 상기 제1 전극과 연결된 제2 전극을 포함하여 상기 제2 전극과 외측 펌핑 전극 사이의 전압을 제어하여 배기가스 중 산소를 제거시키는 질소산화물 센서. The inner pumping electrode is provided on one side of the first cavity to remove oxygen, and installed on the other side of the first cavity, and includes a second electrode connected to the first electrode and an outer side of the second electrode. A nitrogen oxide sensor that removes oxygen from exhaust gas by controlling the voltage between pumping electrodes.
  6. 제5 항에 있어서,The method of claim 5,
    일단은 상기 제1 캐비티와 연결되고 타단은 상기 제2 캐비티와 연결되어 상기 제1 캐비티를 통과한 배기가스를 소정의 확산 저항아래에서 상기 제2 캐비티로 이끄는 제2 확산통로를 포함하는 질소산화물 센서. A nitrogen oxide sensor having a second diffusion passage connected to the first cavity at one end thereof and connected to the second cavity to direct exhaust gas passing through the first cavity to the second cavity under a predetermined diffusion resistance. .
  7. 제5 항에 있어서,The method of claim 5,
    상기 고체전해질 층은 복수개의 기판층으로 이루어진 질소산화물 센서.The solid electrolyte layer is nitrogen oxide sensor consisting of a plurality of substrate layers.
PCT/KR2015/010893 2014-11-06 2015-10-15 Nitrogen oxide sensor WO2016072633A1 (en)

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CN109298057A (en) * 2018-09-03 2019-02-01 上海长园维安电子线路保护有限公司 A kind of nitrogen oxide sensor ceramic chip

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