CN217443234U

CN217443234U - Device for detecting ammonia and nitrogen oxide and nitrogen-oxygen sensor

Info

Publication number: CN217443234U
Application number: CN202123217479.9U
Authority: CN
Inventors: 赵振兴
Original assignee: Great Wall Motor Co Ltd
Current assignee: Great Wall Motor Co Ltd
Priority date: 2021-12-20
Filing date: 2021-12-20
Publication date: 2022-09-16
Anticipated expiration: 2031-12-20

Abstract

The application provides a device for detecting ammonia and nitrogen oxides, which comprises a base body, wherein an air inlet, a first chamber, a second chamber, a third chamber and an air outlet are sequentially arranged on the base body; wherein the first chamber is used for removing NH in the tail gas ₃ Conversion to N ₂ And can measure the current change or voltage change in the reaction process; the second chamber is used for enabling the target gas in the tail gas to generate oxidation reaction and is used for leading NO in the tail gas to be converted ₂ Conversion to NO, target gases including HC, CO and H ₂ One or more of (a); the third chamber is used for decomposing NOIs N ₂ And O ₂ And can measure the current change or the voltage change during the reaction. Through the device provided by the utility model, satisfied the accurate measurement to ammonia and nitrogen oxide content simultaneously.

Description

Device for detecting ammonia and nitrogen oxide and nitrogen-oxygen sensor

Technical Field

The application relates to the field of sensors, in particular to a device for detecting ammonia and nitrogen oxides and a nitrogen-oxygen sensor.

Background

The diesel engine gradually becomes the most popular transportation tool in the existing transportation field due to the limitations of strong dynamic property, low fuel consumption, good economic performance and the like, however, the tail gas discharged in the running process of the diesel engine can cause serious pollution to the environment, the gas pollutants in the tail gas occupy more than 10% of the discharge of all the environmental pollutants, and the gas pollutants in the tail gas mainly comprise carbon monoxide, hydrocarbon, particulate matters and oxynitride. Aiming at the problem, the motor vehicle pollutant emission standard is established in China to limit the emission of pollutants in the tail gas, and after the development process of promotion from China I to China VI, the emission of pollutants in the tail gas can be reduced by 50% every time the standard is improved.

At present, China already implements the national VI b, NO _X The emission limit of (c) falls to 82.1%. The main post-treatment route aiming at the emission regulation of light diesel vehicles to the national VI in the industry at present is that LNT (Low-Density Diesel Engine) is combined with DPF (Diesel particulate Filter) and SCR (Selective catalytic reduction) or DOC (domestic Diesel Engine) is combined with SDPF (Selective catalytic reduction) and SCR (Selective catalytic reduction), wherein SCR is used as an essential core unit in the tail gas treatment route and utilizes an injected reducing agent NH (NH) under an oxygen-containing atmosphere ₃ Or urea reacts with nitrogen oxides in tail gas to catalytically reduce nitrogen oxides into N harmless to environment ₂ And H ₂ And O. The reaction formula is as follows:

2NH ₃ +NO+NO ₂ →2N ₂ +3H ₂ O (1)

8NH ₃ +6NO ₂ →7N ₂ +12H ₂ O (2)

4NH ₃ +4NO+O ₂ →4N ₂ +6H ₂ O (3)

as can be seen from the equations (1), (2) and (3), NH is consumed by the three reactions ₃ Is different, and therefore the prior art is all controlling the over-injection of NH from urea injection systems ₃ To ensure the sufficient decomposition of the oxynitride. NH (NH) ₃ The over-spraying not only causes the waste of raw materials and the rise of cost, but also produces secondary pollution to the environment again.

Therefore, in the related art, a method for injecting NH is needed ₃ Means for performing the measurements.

SUMMERY OF THE UTILITY MODEL

In view of the above, the present invention provides a device and a nitrogen oxide sensor for detecting ammonia and nitrogen oxide.

The technical scheme of the utility model is that: a device for detecting ammonia and nitrogen oxides comprises a substrate, wherein an air inlet, a first chamber, a second chamber, a third chamber and an air outlet are sequentially arranged on the substrate, the second chamber is simultaneously communicated with the first chamber and the third chamber, the first chamber is communicated with the air inlet, and the third chamber is communicated with the air outlet;

wherein the first chamber is used for converting NH in tail gas ₃ Conversion to N ₂ And can measure the current change or voltage change in the reaction process;

the second chamber is used for enabling the target gas in the tail gas to generate oxidation reaction and is used for enabling NO in the tail gas to generate oxidation reaction ₂ Conversion to NO, the target gas including HC, CO and H ₂ One or more of;

the third chamber is used for decomposing NO into N ₂ And O ₂ And can measure the current change or the voltage change in the reaction process.

Optionally, an oxygen pumping inner electrode is arranged in the first chamber, a common outer electrode is arranged above the substrate, and the common outer electrode and the oxygen pumping inner electrode are connected to form an oxygen pumping unit IP1 and a first chamber oxygen concentration unit V1; wherein the pump oxygen inner electrode is coated with a gas for trapping the NH introduced into the first chamber ₃ Of the material layer of (A) so that the NH is present ₃ Conversion to N ₂ ；

Wherein the pump oxygen unit IP1 is used for mixing the NH ₃ Conversion to N ₂ O produced during this reaction of ^2- Pumping out the first chamber, the first chamber oxygen concentration cell V1 for the O based on the O being pumped out ^2- The resulting current or voltage change determines the NH passing into the first chamber ₃ And (4) content.

Optionally, the material layer comprises a plurality of Pt strips, the Pt strips are coated on the lower surface of the first substrate at intervals, a NiO layer is coated on each Pt strip, and an Au strip is coated between any two adjacent Pt strips;

wherein the NiO layer is used for capturing the NH ₃ Said plurality of Pt bands being for catalysisThe NH ₃ Reaction of the Au tape to promote the NH ₃ And (4) reacting.

Optionally, the base includes, from top to bottom, a first substrate, a second substrate, a third substrate, a fourth substrate, and a fifth substrate;

wherein the first substrate and the second substrate together form the first chamber, the second chamber and the third chamber; the third substrate is positioned on the left side of the second substrate, and the second substrate, the third substrate and the fourth substrate form a reference chamber communicated with air together; the fourth substrate and the fifth substrate jointly form a heating cavity, and a heating unit is arranged in the heating cavity.

Optionally, a main pump inner electrode is arranged in the second chamber, an auxiliary pump inner electrode and a reference inner electrode are arranged in the third chamber, and a reference outer electrode is arranged in the reference chamber; the common outer electrode is connected with the main pump inner electrode to form a main pump unit IP 0; the common outer electrode is connected with the auxiliary pump inner electrode to form an auxiliary pump unit IP 3; the common external electrode and the reference external electrode are connected to form a total oxygen concentration unit V0; the reference outer electrode is connected with the main pump inner electrode to form a second chamber oxygen concentration unit V2; the reference outer electrode and the reference inner electrode are connected to form a reference unit V3, and the auxiliary pump inner electrode and the common outer electrode are connected to form a third chamber oxygen concentration unit V4;

wherein the main pump unit IP0 is used for mixing O ₂ Pumping out the second chamber or ₂ Pumping into the second chamber, and maintaining the oxygen concentration of the second chamber to a constant value by the second chamber oxygen concentration difference unit V2 through feedback regulation;

the secondary pump unit IP3 is used for decomposing NO into O ₂ Pumping out the third chamber, a third chamber oxygen concentration unit V4 for the O based on the O pumped out ₂ The resulting current or voltage change determines the nitrogen oxide content of the gas introduced into the third chamber.

Optionally, the main pump inner electrode comprises a plurality of Pt strips, the Pt strips are coated on the lower surface of the first substrate, and an Au strip is coated between any two adjacent Pt strips.

Optionally, the size of the Pt band, the NiO layer and the Au band are all the same and not less than 1 μm.

Optionally, the second chamber is also coated with ZnFe ₂ O ₄ Coating of said ZnFe ₂ O ₄ The coating is used for capturing and catalyzing NO flowing through the second chamber ₂ 。

Optionally, the output end of the device is connected with the input end of a control unit, and the control unit is used for controlling the voltage directions of the oxygen pumping unit IP1 and the main pumping unit IP 0.

The utility model also provides a nitrogen oxygen sensor, including the nitrogen oxygen sensor body, including sensor plug, sensor probe, thread and computer board on the nitrogen oxygen sensor body, the sensor probe internal fixation is provided with as above the device that is used for detecting ammonia and nitrogen oxide.

Compared with the prior art, the method has the following advantages:

adopt the technical scheme of this application, through the first cavity that constitutes by first base plate and second base plate, be equipped with the pump oxygen internal electrode in the first cavity, the top of first base plate is equipped with public outer electrode, public outer electrode with the pump oxygen internal electrode is connected and is formed pump oxygen unit IP1 and first cavity oxygen concentration unit V1, and the pump oxygen internal electrode of first cavity has to NH ₃ Has excellent trapping property, is not sensitive to HC, CO and other substances, and can effectively promote' NH ₃ And O ^2- And O to be involved in the reaction ^2- Pumped out of the pump oxygen inner electrode through a pump oxygen unit IP1, O ^2- The electrolyte vacancies formed by the first substrate are transferred to the common external electrode to pass through O ^2- Generating a potential difference V1 to realize the pair NH ₃ Measurement of the content of (b). And NO is realized through the cooperation of the second chamber and the third chamber _X The measurement of (2). Through the device provided by the utility model, it can not be to NH to have broken current diesel engine tail gas aftertreatment ₃ The barrier to measure can accurately provide NH for the urea injection system ₃ And at the same time, the nitrogen oxide measurement is realizedEffectively saving the economic cost and protecting the environment.

Drawings

In order to more clearly illustrate the technical solutions of the present application, the drawings needed to be used in the description of the present application will be briefly introduced below, and it is apparent that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without inventive labor.

FIG. 1 is a schematic view of the overall structure of the device for detecting ammonia and nitrogen oxides according to the present invention;

FIG. 2 is an enlarged view taken at a point a of FIG. 1;

fig. 3 is a sectional view of an electrode in a main pump according to an embodiment of the present invention.

Description of the reference numerals:

1. a first substrate; 2. a sixth substrate; 3. a second substrate; 4. a third substrate; 5. a fourth substrate; 6. a fifth substrate; 7. a common outer electrode; 8. a heating unit; 9. a first chamber; 10. a second chamber; 11. a third chamber; 12. a pump oxygen inner electrode; 121. a Pt tape; 122. an Au tape; 123. a NiO layer; 13. a main pump inner electrode; 14. an auxiliary pump inner electrode; 15. a reference inner electrode; 16. a reference chamber; 17. reference is made to the outer electrode.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some, but not all, embodiments of the present application. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments in the present application without making any creative effort belong to the protection scope of the present application.

In the related art, on the one hand, NH ₃ The over-spraying not only causes the waste of raw materials and the rise of cost, but also produces secondary pollution to the environment again.

On the other hand, in order to effectively control and achieve the emission content of oxynitride in the tail gasAccording to the requirements of regulations, two nitrogen-oxygen sensors are arranged in the tail gas aftertreatment route to measure the content of nitrogen oxides before and after treatment. A common nitrogen-oxygen sensor is provided with two chambers, tail gas passes through the two chambers in sequence, wherein the first-passing chamber can utilize peripheral oxygen to react carbon monoxide and hydrocarbon in the tail gas to generate CO ₂ And H ₂ O, post-entry chamber catalytically decomposes remaining NO to N ₂ And O ₂ Decomposed O ₂ Is pumped out in the second chamber, thereby generating an electric current, so that the nitrogen oxide content of the exhaust gas can be calculated from the current value.

Because the nitrogen oxide is mainly composed of NO and NO ₂ By construction, NO cannot be measured by existing sensors ₂ The measured content of the oxynitride is lower than the actual content of the oxynitride, and therefore, the existing oxynitride sensor has the problem of lower accuracy in measuring the oxynitride content in the exhaust gas.

In view of the above, the applicant proposes the following technical idea:

the proposed device for detecting ammonia and nitrogen oxides may be an improvement to existing nitrogen-oxygen sensors, based on which the measurement of N is based ₂ Mounting position and NH of ₃ The measuring unit measures NH ₃ Can be installed at the same position, namely NH is added on the prior nitrogen oxygen sensor ₃ A measuring unit for measuring NH by the existing nitrogen-oxygen sensor ₃ And can measure oxynitride; in still another aspect, the device for detecting ammonia and nitrogen oxides can accurately obtain the content of nitrogen oxides.

Referring to fig. 1, fig. 1 is a schematic diagram illustrating an overall structure of an apparatus for detecting ammonia and nitrogen oxides according to the present invention. As shown in fig. 1, the utility model provides a device for detecting ammonia and nitrogen oxide, which comprises a base body, wherein an air inlet, a first chamber 9, a second chamber 10, a third chamber 11 and an air outlet are sequentially arranged on the base body, the second chamber 10 is communicated with the first chamber 9 and the third chamber 11 simultaneously, the first chamber 9 is communicated with the air inlet, and the third chamber 11 is communicated with the air outlet;

wherein the first chamber 9 is used for removing NH in the exhaust gas ₃ Conversion to N ₂ And can measure the current change or voltage change in the reaction process;

the second chamber 10 is used for oxidizing the target gas in the exhaust gas and for converting NO in the exhaust gas ₂ Conversion to NO, target gases including HC, CO and H ₂ One or more of;

the third chamber 11 is used for decomposing NO into N ₂ And O ₂ And can measure the current change or the voltage change during the reaction.

The present invention can be used in an apparatus for detecting ammonia and nitrogen oxides by chemical reactions occurring in the first, second and third chambers, thereby generating charge movement and generating an electric current. The substrate refers to a material capable of passing electric charges, such as a ceramic substrate.

Tail gas enters the device from the gas inlet and sequentially passes through the first chamber, the second chamber and the third chamber. And generating difference values of the concentrations of the gas and the tail gas in the first chamber, the second chamber and the third chamber, wherein the difference values form current change or voltage change, so that current signals or voltage signals are output, and the content of the target object in the corresponding chambers is measured.

Optionally, an oxygen pumping inner electrode 12 is arranged in the first chamber 9, a common outer electrode 7 is arranged above the first substrate 1, and the common outer electrode 7 is connected with the oxygen pumping inner electrode 12 to form an oxygen pumping unit IP1 and a first chamber oxygen concentration unit V1; wherein the pump oxygen inner electrode 12 is coated with a gas for trapping NH introduced into the first chamber 9 ₃ Of a layer of material such that NH ₃ Conversion to N ₂ ；

Wherein the pump oxygen unit IP1 is used for mixing NH ₃ Conversion to N ₂ O produced during this reaction of ^2- The first chamber 9 is pumped out, the first chamber oxygen concentration cell V1 is used for the O based pumping out ^2- The resulting potential difference determines the NH passing into the first chamber 9 ₃ And (4) content.

The working principle of the technical scheme is as follows:

the first chamber 9 is internally provided with a pump oxygenAn electrode 12, a common external electrode 7 disposed above the first substrate 1, the common external electrode 7 connected with the pumping oxygen internal electrode 12 to form a pumping oxygen unit IP1 and a first chamber oxygen concentration unit V1, the pumping oxygen internal electrode 12 of the first chamber 9 having a pair NH ₃ Has excellent trapping property, is not sensitive to HC, CO and other substances, and can effectively promote' NH ₃ And O ^2- And O to be involved in the reaction ^2- Pumped out of pump oxygen inner electrode 12 through pump oxygen unit IP1 ^2- The electrolyte vacancies formed by the first substrate 1 are transferred to the common external electrode 7 to pass through O ^2- Generating a potential difference V1 to realize the pair NH ₃ Measurement of the content of (c); meanwhile, the tail gas passing through the first chamber 9 enters the second chamber 10, and the second chamber 10 utilizes the peripheral O ₂ Removing CO, HC and H in tail gas ₂ Separate formation of CO ₂ And H ₂ O, the exhaust gas passing through the second chamber 10 enters the third chamber 11, and the third chamber 11 decomposes NO in the exhaust gas into N ₂ Due to reduced NO _X The resulting potential difference enables the measurement of nitrogen oxides. Realize that the device can measure NH ₃ In turn, nitrogen oxides can be measured.

Fig. 2 shows an enlarged view at a of fig. 1. As shown in FIG. 2, an inner pump oxygen electrode 12 is disposed in the first chamber 9, and NH is captured on the inner pump oxygen electrode 12 ₃ The material layer comprises a plurality of Pt strips 121, the Pt strips 121 are uniformly coated on the lower surface of the first substrate 1 at intervals, a NiO layer 123 is coated on each Pt strip 121, and an Au strip 122 is coated between any two adjacent Pt strips 121; the Pt material has stable chemical property, the formed loop has excellent conductive performance, does not participate in electrode reaction, and simultaneously catalyzes NH ₃ And (4) reacting. Therefore, the Pt band can be replaced with a transition metal electrode material such as a Ni band, a Ru band, an Ir band, or a compound thereof, which increases the cost and decreases the measurement accuracy. Because the structure controllability of Pt belt is high, accord with the Nernst effect, the adoption in Pt belt is guaranteed the utility model provides a measuring performance of device is highest and production manufacturing cost is lowest.

Wherein NiO layer 123 is used for trapping NH ₃ Multiple strips of Pt 121 for catalyzing NH ₃ Reaction, Au tape 122 to promote NH ₃ And (4) reacting.

123 pair of NH of NiO layer ₃ Has excellent capturing and catalytic properties, and the Au band 122 therein is coupled with' NH ₃ And O ^2- The reaction of (3) is promoted, and particularly, the Au ribbons 122 have a strong affinity for the NiO layer 123, and the combination of the two can improve the reaction of (2) with NH ₃ Capture and catalysis ".

The apparatus further comprises a heating unit 8, the heating unit 8 being adapted to provide a reaction temperature to the first chamber 9. Preferably, the heating unit 8 can be a Pt electrode, the device is heated by the heating Pt electrode during measurement, and O can be enabled by utilizing the electrolyte characteristic presented by the zirconia substrate at high temperature ₂ With O ^2- Is pumped out of the interior of the first substrate 1.

Through the technical scheme of the utility model, when tail gas and the NH that needs catalytic reduction ₃ Enters the first chamber 9 to contact with the pump oxygen inner electrode 12, the Pt strip on the pump oxygen inner electrode 12 and the Pt electrode of the common outer electrode 7 form a loop, and the loop is connected with the pump oxygen inner electrode 12 ₂ With trapping property, NiO layer 123 is coated on the upper surface of Pt belt 121, and NiO layer 123 is opposite to NH ₃ Has excellent capturing and catalytic properties, and the Au band 122 therein is coupled with' NH ₃ And O ^2- The reaction of (3) is promoted, and the combination of the NiO layer 123 and the Au strip 122 improves the reaction of' on NH ₃ Capture and catalysis "; NH (NH) ₃ The reaction occurs after the NiO-Au complex structure is captured, as shown in formula (4). O is ₂ Electrons (2e/4e) are obtained from the pump oxygen internal electrode 12 as O ^2- By the form of ₂ The first substrate 1' of the main material moves rapidly towards the common outer electrode 7, thereby changing the potential difference/current difference which can be converted into NH ₃ The quantity signal of (2).

² / ₃ NH ₃ + ¹ / ₂ O ₂ (O ^2- )→ ¹ / ₃ N ₂ +H ₂ O (4)

The tail gas passing through the first chamber 9 enters the second chamber 10 and the third chamber 11 in sequence, and the second chamber 10 reduces HC, CO and H in the tail gas ₂ The third chamber 11 reduces NO in the exhaust gas _X . Through the utility model provides aRealize the response chip that ammonia and oxynitrides detected, solved the problem that the traditional sensor can not measure NH ₃ Result in NH ₃ Over-spraying defect, the first chamber 9 is added on the basis of the nitrogen oxygen sensor, and NH is accurately realized ₃ While measuring, no new sensor or NH is added ₃ The related measurement system keeps the original post-processing system structure and has great economic and social benefits.

Optionally, the base includes, from top to bottom, a first substrate 1, a second substrate 3, a third substrate 4, a fourth substrate 5, and a fifth substrate 6, where the first substrate 1 and the second substrate 3 together form a first chamber 9, a second chamber 10, and a third chamber 11; the third substrate 4 is positioned at the left side of the second substrate 3, and the second substrate 3, the third substrate 4 and the fourth substrate 5 together form a reference chamber 16 communicated with air; the fourth substrate 5 and the fifth substrate 6 together form a heating chamber in which a heating unit is disposed.

Correspondingly, a stacked sixth substrate 2 is further included between the first substrate 1 and the second substrate 3, and the first chamber 9, the second chamber 10, and the third chamber 11 are located on the same horizontal line with the sixth substrate 2. The sixth substrate 2 is arranged to layer the device according to the electrolyte transmission route, so that the first chamber 9, the second chamber 10, the third chamber 11 and the corresponding conductive electrodes are convenient to manufacture. In another alternative to this embodiment, the first chamber 9, the second chamber 10 and the third chamber 11 may be separately located in the sixth substrate 2. And the utility model discloses a setting has utilized the available space of first base plate 1 and second base plate 3 simultaneously, has improved the area of cavity and has not influenced O ^2- The passing path of (a).

The utility model discloses a first base plate 1 and second base plate 3, third base plate 4, fourth base plate 5 and fifth base plate 6 and sixth base plate 2 are compound zirconia base plate.

Note that, ZrO is absolutely pure ₂ Is an insulator, and is made to effectively conduct O ^2- The utility model discloses add Y in first base plate 1, second base plate 3, third base plate 4, fourth base plate 5, fifth base plate 6 and sixth base plate 2 ₂ O ₃ Or CaO, to achieve an increaseO ^2- Concentration of vacancies such that ZrO ₂ At low temperature in the form of cubes or cubes, larger voids are present in the unit cell, so that O ^2- Is unobstructed in the vacancy, and the conductivity/O of the alloy is improved ^2- The flow rate. Preferably, the yttria component is from 8% to 10% by volume of the zirconia component and the calcia component is from 8% to 10% by volume of the zirconia component.

More specifically, a main pump inner electrode 13 is arranged in the second chamber 10, a secondary pump inner electrode 14 and a reference inner electrode 15 are arranged in the third chamber 11, and a reference outer electrode 17 is arranged in the reference chamber 16; the common external electrode 7 is connected with the main pump internal electrode 13 to form a main pump unit IP 0; the common external electrode 7 is connected with the auxiliary pump internal electrode 14 to form an auxiliary pump unit IP 3; the common external electrode 7 is connected with the reference external electrode 17 to form a total oxygen concentration unit V0; the reference outer electrode 17 is connected with the main pump inner electrode 13 to form a second chamber oxygen concentration unit V2; the reference outer electrode 17 and the reference inner electrode 15 are connected to form a reference unit V3, and the auxiliary pump inner electrode 14 and the common outer electrode 7 are connected to form a third chamber oxygen concentration unit V4;

wherein the main pump unit IP0 is used for mixing O ₂ Pumping out the second chamber 10 or ₂ Pumping into the second chamber 10, wherein V0 is the total O in the exhaust emission of the whole device ₂ Concentration difference, the second chamber oxygen concentration unit V2 maintains the oxygen concentration of the second chamber 10 to a constant value through feedback regulation; specifically, for sufficient oxidation of the target gas within the second chamber 10, it is necessary to maintain O within the second chamber 10 ₂ And (4) concentration. V2 may represent the oxygen concentration in the second chamber 10. by detecting the difference between V2 and V0, O in the second chamber 10 may be determined ₂ Whether the concentration is sufficient for the reaction of the target gas or exceeds the reaction concentration of the target gas, the direction of the oxygen pumping required by the device is fed back and adjusted according to the oxygen concentration value in the second chamber 10, i.e. the oxygen concentration needs to be supplemented or reduced, so as to maintain the oxygen concentration in the second chamber 10.

The secondary pump unit IP3 being for O decomposing NO ₂ Pumping out the third chamber 11, the third chamber oxygen concentration cell V4 for O based on the pumped out ₂ The resulting current or voltage changesThe nitrogen oxide content is determined in the third chamber 11.

V3 is a reference cell formed by reference outer electrode 17 and reference inner electrode 15, the reference cell being used to provide a reference oxygen concentration. By detecting the potential difference between the reference outer electrode 17 and the reference inner electrode 15, a reference concentration of oxygen in the third chamber 11 can be obtained, the reference concentration of oxygen being the O of the gas entering the third chamber 11 from the second chamber 10 ₂ Concentration and/or original O in the third chamber 11 ₂ And (4) concentration. The reference unit V3 has a determined electrode potential, the potential difference of the measuring electrode can be rapidly and accurately obtained by comparing the potential of the measuring electrode with the known potential V3, and the content of the measured object can be calculated through the potential difference.

In this embodiment, the exhaust gas passing through the first chamber 9 enters the second chamber 10, and the main pump inner electrode 13 of the second chamber 10 utilizes the peripheral O ₂ Removing CO, HC and H in tail gas ₂ Separate formation of CO ₂ And H ₂ O, as in formulas (5), (6) and (7).

CO+1/2O ₂ →CO ₂ (5)

HC+O ₂ →H ₂ O+CO ₂ (6)

H ₂ +1/2O ₂ →CO ₂ (7)

The main pump unit IP0 is formed by connecting the common external electrode 7 to the main pump internal electrode 13, and the reference external electrode 17 is formed by connecting the reference external electrode 17 to the main pump internal electrode 13 to form the second chamber oxygen concentration unit V2. V2 maintains the oxygen concentration in the second chamber 10 to a constant value by feedback regulation, so as to make HC, CO and H in the exhaust gas ₂ And (4) fully oxidizing. The exhaust gas after the completion of the oxidation reaction, when a voltage is applied to the first substrate 1, is applied with a positive polarity to the common external electrode 7 and a negative polarity to the main pump internal electrode 13, thereby forming a main pump unit IP0, O on the main pump internal electrode 13 ₂ To obtain electrons (4e) to form O ^2- ，O ^2- Rapidly migrates to the common external electrode 7 on the low oxygen concentration side through oxygen vacancies in the electrolyte of the first substrate 1, and O is formed on the common external electrode 7 ^2- Then lose electrons and oxygen molecule O ₂ The state is released. As in equations (8) and (9):

O ₂ +4e→2O ^2- (8)

2O ^2- -4e→O ₂ (9)

the exhaust gas passing through the second chamber 10 enters the third chamber 11, and only NO remains in the exhaust gas _X The secondary pump inner electrode 14 of the third chamber 11 decomposes NO in the exhaust gas into N ₂ And O ₂ Such as reaction formula (10).

2NO→N ₂ +O ₂ (10)

The common external electrode 7 is connected with the auxiliary pump internal electrode 14 to form an auxiliary pump unit IP3 and a third chamber oxygen concentration unit V4. When a voltage is applied to the first substrate 1, a positive electrode is applied to the common external electrode 7 and a negative electrode is applied to the sub-pump internal electrode 14, thereby forming a sub-pump cell IP3, O ₂ The electrons (4e) are obtained from the sub-pump internal electrode 14 to form O ^2- ，O ^2- Rapidly migrates to the common external electrode 7 on the low oxygen concentration side through oxygen vacancies in the electrolyte of the first substrate 1, and O is formed on the common external electrode 7 ^2- Then lose electrons and oxygen molecule O ₂ The state is released. O is ^2- Thus, the potential difference/current difference is changed, and the potential difference/current difference can be converted into a NO quantity signal.

Referring to fig. 3, fig. 3 is a cross-sectional view of an inner electrode of a main pump according to an embodiment of the present invention. As a modification of the present embodiment, the main pump internal electrode 13 includes a plurality of Pt ribbons 121, the plurality of Pt ribbons 121 are coated on the lower surface of the first substrate 1, and Au ribbons 122 are coated between any two adjacent Pt ribbons 121. By the criss-cross arrangement of the Pt ribbons 121 and the Au ribbons 122, the Au ribbons 122 trap HC, CO, H ₂ And O ₂ While ensuring NO _X Is oxidized to ensure that NO is measured in the third chamber 11 _X And (4) accuracy.

Further, the size of the Pt tape 121, NiO layer 123, and Au tape 122 are all the same and not less than 1 μm. The Pt zone 121, the NiO layer 123 and the Au zone 122 are all 1 μm, so that the coating difficulty is low, the sensitivity to the capture of ions is high, and the applicable zirconia base material is wide.

As a modification of this embodiment, the second chamber 10 is also coated with ZnFe ₂ O ₄ Coating of ZnFe ₂ O ₄ The coating serves to trap and catalyse the flow of NO through the second chamber 10 ₂ . By arranging ZnFe in the second chamber 10 ₂ O ₄ Coating of NO by the substance ₂ Has excellent trapping and catalytic properties. It can be catalyzed to give NO, as in formula (11).

NO ₂ →NO+O (11)

Due to NO _X With NO ₂ And NO mainly, and NO has not been treated at present ₂ Is measured. With the arrangement of the present embodiment, NO entering the third chamber 11 _X Both are NO, and are decomposed in the third chamber 11 as shown in equation (10). Realize NO ₂ Conversion to NO to effect NO _X The accurate measurement of the nitrogen oxide content and the nitrogen oxide content in the sample can be realized, and the problem that the nitrogen oxide content represents the nitrogen oxide content in the traditional technology can be solved.

In another embodiment, the output of the device is connected to the input of a control unit for controlling the voltage direction of the oxygen pumping unit IP1 and the main pumping unit IP 0.

NH when the engine is in a lean burn phase ₃ Into the first chamber 9, a reduction reaction takes place at the pump oxygen inner electrode 12 as in equation (4). And when containing HC, CO, H ₂ 、O ₂ Reaches the second chamber, HC, CO, H ₂ With O under the catalytic action of Pt ₂ The reaction takes place as in equations (5), (6) (7). Because the lean burn stage is characterized by oxygen enrichment, in addition to Pt for O ₂ Having capturing property, O ₂ Electrons (2e/4e) are obtained at the three-phase interface between the pump oxygen inner electrode 12 and the main pump inner electrode 13 as O ^2- Is moved rapidly towards the common outer electrode 7.

When the engine is in a rich combustion stage, the whole device is anoxic, and the difference between the potential difference between the oxygen pumping inner electrode 12 and the common outer electrode 7 and the potential difference between the main pump inner electrode 13 and the common outer electrode 7 are changed. At this time, the voltage direction of IP1 is changed by the control unit, i.e. pumping oxygen inner electrode 12 is electrified positively, common outer electrode 7 is electrified negatively, so that O of common outer electrode 7 ₂ Obtaining electrons (2e/4e) as O at the "three-phase interface ^2- In the form of a rapidly moving electrode towards the pump oxygen inner electrode. Electrode 12 is lost in pumping oxygenElectrons to O ₂ For replenishing O of the first chamber 9 ₂ And with NH ₃ A reaction as in equation (4) occurs.

Similarly, the voltage direction of the IP0 is changed by the control unit, the main pump inner electrode 13 is electrified positively, the common outer electrode 7 is electrified negatively, and O is generated on the main pump inner electrode 13 ₂ For replenishing the first chamber 9 ₂ And is combined with HC, CO, H ₂ The reaction takes place under the catalytic action of Pt as in the above equation (8) (9) (10). To ensure sufficient oxidation in the second chamber 10. Through the utility model discloses a set up, solved prior art O effectively ₂ Insufficient to affect the nitroxide measurement.

The specific way of changing the voltage direction of the IP1 and the voltage direction of the IP0 through the control unit is as follows: the electrified positive and negative poles of the common external electrode 7 and the pump oxygen internal electrode 12 are respectively changed, and the electrified positive and negative poles of the common external electrode 7 and the main pump internal electrode 13 are respectively changed.

Three cavities on the substrate 1 can be applied to the common outer electrode 7 in the working process, and in the embodiment of the application, the pump oxygen inner electrode 12, the main pump inner electrode 13 and the auxiliary pump inner electrode 14 are sequentially electrified with the common outer electrode 7. For example, the pump oxygen internal electrode 12 in the first chamber 9 is energized with the common external electrode 7 for the first 0.1 second, the pump oxygen internal electrode 12 in the second chamber 10 is energized with the common external electrode 7 for the second 0.1 second, and the sub-pump internal electrode 14 in the third chamber 11 is energized with the common external electrode 7 for the third 0.1 second. Here, 0.1 second may also be set to 0.15 second, 0.2 second, or the like according to practical applications. By sequentially energising the common outer electrode 11 with the electrode connections in the three chambers, the exhaust gas may be sequentially treated as it passes through the three chambers within the sensor.

Based on the same conception, in another embodiment, the utility model also provides a nitrogen oxygen sensor, including the nitrogen oxygen sensor body, including sensor plug, sensor probe, thread and computer board on the nitrogen oxygen sensor body, the sensor probe internal fixation is provided with the above device that is used for detecting ammonia and nitrogen oxide.

It is to be understood that the device provided by the present invention may be mounted on any sensor based on the same or similar principles and is not limited to nitrogen oxide sensors.

It should be understood that while the present specification has described preferred embodiments of the present application, additional variations and modifications of those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including the preferred embodiment and all such alterations and modifications as fall within the true scope of the embodiments of the application.

The device for detecting ammonia and nitrogen oxides and the nitrogen oxide sensor provided by the present application are described in detail above, and specific examples are applied herein to illustrate the principles and embodiments of the present application, and the description of the above embodiments is only used to help understand the method and the core concept of the present application; meanwhile, for a person skilled in the art, according to the idea of the present application, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present application.

Claims

1. A device for detecting ammonia and nitrogen oxides is characterized by comprising a base body, wherein an air inlet, a first chamber, a second chamber, a third chamber and an air outlet are sequentially arranged on the base body, the second chamber is simultaneously communicated with the first chamber and the third chamber, the first chamber is communicated with the air inlet, and the third chamber is communicated with the air outlet;

the second chamber is used for enabling the target gas in the tail gas to generate oxidation reaction and is used for enabling NO in the tail gas to generate oxidation reaction ₂ Conversion to NO;

the third chamber is used for decomposing NO into N ₂ And O ₂ And can measure the current change or the voltage change during the reaction.

2. The device of claim 1, wherein an oxygen pumping internal electrode is arranged in the first chamber, a common external electrode is arranged above the substrate, and the common external electrode is connected with the oxygen pumping internal electrode to form an oxygen pumping unit IP1 and a first chamber oxygen concentration unit V1; wherein the pump oxygen inner electrode is coated with a gas for trapping the NH introduced into the first chamber ₃ Of the material layer of (A) so that the NH is present ₃ Conversion to N ₂ ；

3. The device for detecting ammonia and nitrogen oxides as claimed in claim 2, wherein said material layer comprises a plurality of Pt strips, said plurality of Pt strips are coated on the lower surface of said substrate at regular intervals, each of said Pt strips is coated with a NiO layer, and any two adjacent Pt strips are coated with Au strips therebetween;

wherein the NiO layer is used for capturing the NH ₃ A plurality of said Pt bands for catalyzing said NH ₃ Reaction of the Au tape to promote the NH ₃ And (4) reacting.

4. The apparatus of claim 2, wherein the base body comprises a first substrate, a second substrate, a third substrate, a fourth substrate and a fifth substrate which are sequentially connected from top to bottom;

5. The apparatus of claim 4, wherein the second chamber has a primary pump inner electrode disposed therein, the third chamber has a secondary pump inner electrode and a reference inner electrode disposed therein, and the reference chamber has a reference outer electrode disposed therein;

wherein the common outer electrode is connected with the main pump inner electrode to form a main pump unit IP 0; the common outer electrode is connected with the auxiliary pump inner electrode to form an auxiliary pump unit IP 3; the common external electrode and the reference external electrode are connected to form a total oxygen concentration unit V0; the reference outer electrode is connected with the main pump inner electrode to form a second chamber oxygen concentration unit V2; the reference outer electrode and the reference inner electrode are connected to form a reference unit V3, and the auxiliary pump inner electrode and the common outer electrode are connected to form a third chamber oxygen concentration unit V4;

the secondary pump unit IP3 is used for decomposing NO into O ₂ Pumping out the third chamber, the third chamber oxygen concentration unit V4 for the O based on the O pumped out ₂ The resulting current or voltage change determines the nitrogen oxide content of the gas introduced into the third chamber.

6. The apparatus of claim 5, wherein the main pump inner electrode comprises a plurality of Pt strips coated on the lower surface of the first substrate, and an Au strip is coated between any two adjacent Pt strips.

7. The apparatus of claim 3, wherein the Pt strips, NiO layer and Au strips are all the same size and not less than 1 μm.

8. The apparatus of claim 1, wherein the second chamber is further coated with ZnFe ₂ O ₄ Coating of said ZnFe ₂ O ₄ The coating is used for capturing and catalyzing NO flowing through the second chamber ₂ 。

9. The device of claim 5, wherein the output end of the device is connected with the input end of a control unit, and the control unit is used for controlling the voltage directions of the pump oxygen unit IP1 and the main pump unit IP 0.

10. A nitrogen-oxygen sensor, comprising a nitrogen-oxygen sensor body, wherein the nitrogen-oxygen sensor body comprises a sensor plug, a sensor probe, a main wire and a computer board, and is characterized in that the device for detecting ammonia and nitrogen oxides as claimed in any one of claims 1 to 9 is fixedly arranged in the sensor probe.