CN116381009A - Sensor and combustion system including same - Google Patents

Abstract

The invention discloses a sensor and a combustion system comprising it. The sensor according to the embodiment of the present invention includes a reference oxygen chamber; a first chamber communicated with the outside world through a first diffusion channel; a second chamber communicated with the first chamber through a second diffusion channel; a third The chamber communicates with the second chamber through a third diffusion channel; the nitrogen and oxygen measuring unit is used for measuring the concentration of nitrogen oxides; and the hydrocarbon measuring unit is used for measuring the concentration of hydrocarbons, wherein the hydrocarbons The measuring unit includes: a hydrocarbon electrode; a reference electrode arranged in the reference oxygen chamber; the hydrocarbon measuring unit obtains the hydrocarbon concentration according to the voltage difference between the hydrocarbon electrode and the reference electrode. The sensor and the combustion system including it according to the embodiment of the present invention are additionally designed with hydrocarbon electrodes for measuring the concentration of hydrocarbons, and integrate the measurement of nitrogen and oxygen and hydrocarbons.

Description

Sensor and combustion system including same

technical field

The invention relates to the technical field of sensors, in particular to a sensor and a combustion system including the same.

Background technique

With the development of economy and society, the number of motor vehicles is also increasing year by year, but the harmful components contained in the tail gas emitted by motor vehicles will cause serious pollution to the atmosphere, such as carbon monoxide, nitrogen oxides (nitrogen monoxide and nitrogen dioxide, collectively referred to as NO _x ), sulfide, fine particles, etc. These harmful ingredients greatly affect the environment and the survival of animals and plants.

In the prior art, sensors are of great significance to motor vehicle exhaust gas treatment systems. However, the current sensors are often special-purpose sensors, which can only detect a certain gas, and have a narrow application range, which cannot meet the detection requirements of multiple gases.

Therefore, a new sensor and a combustion system including the same are desired.

Contents of the invention

In view of the above problems, the object of the present invention is to provide a sensor and a combustion system including the same, so as to measure the concentration of hydrocarbons through additionally designed hydrocarbon electrodes.

According to one aspect of the present invention, there is provided a sensor, comprising: a reference oxygen chamber; a first chamber communicating with the outside world through a first diffusion channel; a second chamber communicating with the first chamber through a second diffusion channel The chambers are communicated; the third chamber is communicated with the second chamber through a third diffusion channel; the nitrogen and oxygen measuring unit is used to measure the concentration of nitrogen oxides; and the hydrocarbon measuring unit is used to measure the concentration of hydrocarbons, Wherein, the hydrocarbon measuring unit includes: a hydrocarbon electrode; a reference electrode, which is arranged in the reference oxygen chamber; the hydrocarbon measuring unit obtains the The stated hydrocarbon concentration.

Optionally, a first pump unit is arranged in the first chamber, and a first Nernst induction unit is formed between the first chamber and the reference oxygen chamber; There is a second pump unit, a second Nernst induction unit is formed between the second chamber and the reference oxygen chamber; and a third pump unit is arranged in the third chamber, the third chamber A third Nernst sensing unit is formed between the chamber and the reference oxygen chamber; the sensor also includes: an external electrode; a third electrode arranged in the third chamber; an excess air coefficient unit for obtaining Excess air ratio, wherein, when the excess air ratio is equal to the set threshold, the nitrogen oxide concentration is obtained according to the Nernst voltage method; when the excess air ratio is greater than the preset threshold, according to the external electrode and The current flow between the third electrodes obtains the nitrogen oxide concentration.

Optionally, the sensor further includes: a first electrode arranged in the first chamber; an upper electrode and a lower electrode oppositely arranged in the second chamber; wherein the first pump The unit includes the outer electrode and the first electrode; the second pump unit includes the outer electrode and the upper electrode or the lower electrode; the third pump unit includes the outer electrode and the first electrode. Three electrodes; the first Nernst sensing unit includes the reference electrode and the first electrode; the second Nernst sensing unit includes the reference electrode and the upper electrode or the lower electrode; The third Nernst sensing unit includes the reference electrode and the third electrode; the reference oxygen chamber is a closed chamber.

Optionally, the sensor further includes: an excess air ratio unit, configured to obtain an excess air ratio, wherein, when the excess air ratio is greater than a set threshold, the hydrocarbon measuring unit The voltage difference between the reference electrodes is used to obtain the hydrocarbon concentration

Optionally, the hydrocarbon measuring unit further includes: a hydrocarbon electrode protection layer covering the surface of the hydrocarbon electrode.

Optionally, the sensor further includes: an oxygen measuring unit for measuring oxygen concentration.

Optionally, the sensor further includes: an excess air coefficient unit, configured to obtain an excess air coefficient, wherein, when the excess air coefficient is less than a set threshold, the oxygen concentration at the external electrode of the sensor and the reference The oxygen concentration is obtained from the oxygen concentration in the oxygen chamber; when the excess air coefficient is greater than a set threshold, the oxygen concentration is obtained according to the current value between the first electrode of the sensor and the external electrode.

Optionally, the sensor further includes: a calibration unit for calibrating the relationship between the hydrocarbon concentration and the voltage difference between the hydrocarbon electrode and the reference electrode under different oxygen concentrations, wherein the hydrocarbon measurement The unit obtains the hydrocarbon concentration according to the relationship between the hydrocarbon concentration under the different oxygen concentrations and the voltage difference between the hydrocarbon electrode and the reference electrode.

Optionally, the sensor further includes: a heater for heating the first chamber, the second chamber and the third chamber.

According to another aspect of the present invention, there is provided a combustion system, comprising: a combustion engine; and the above-mentioned sensor, which is connected to the combustion engine to detect exhaust gas of the combustion engine.

The sensor and the combustion system including it according to the embodiments of the present invention are additionally designed with hydrocarbon electrodes for measuring the concentration of hydrocarbons, and integrate the measurement of nitrogen and oxygen and hydrocarbons.

Further, the sensor integrates oxygen, nitrogen oxygen and hydrocarbon measurement capabilities.

Furthermore, the sensor adopts different measurement methods under different excess air coefficients to ensure the accuracy of measurement.

Further, the sensor calibrates the relationship between the hydrocarbon concentration and the EMF under different oxygen concentrations, and the hydrocarbon concentration is measured according to the calibrated relationship, which ensures the accuracy of the hydrocarbon concentration measurement.

Description of drawings

Through the following description of the embodiments of the present invention with reference to the accompanying drawings, the above-mentioned and other objects, features and advantages of the present invention will be more clear, in the accompanying drawings:

Fig. 1 shows a schematic structural diagram of a sensor according to an embodiment of the present invention.

Fig. 2 shows a schematic diagram of the measurement principle of the sensor according to an embodiment of the present invention when the excess air coefficient is less than a set threshold.

Fig. 3 shows a schematic diagram of the measurement principle of the sensor according to an embodiment of the present invention when the excess air coefficient is greater than a set threshold.

Fig. 4 shows a schematic diagram of the hydrocarbon measurement principle of the sensor according to the embodiment of the present invention.

Fig. 5 shows a schematic diagram of hydrocarbon concentration calibration according to an embodiment of the present invention.

Detailed ways

Various embodiments of the invention will be described in more detail below with reference to the accompanying drawings. In the various drawings, the same elements are denoted by the same or similar reference numerals. For the sake of clarity, various parts in the drawings have not been drawn to scale. Also, some well-known parts may not be shown in the drawings.

The specific implementation manners of the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. In the following, many specific details of the present invention, such as structures, materials, dimensions, processes and techniques of components, are described for a clearer understanding of the present invention. However, the invention may be practiced without these specific details, as will be understood by those skilled in the art.

It should be understood that when describing the structure of a component, when a layer or a region is referred to as being "on" or "over" another layer or another region, it may mean being directly on another layer or another region, or Other layers or regions are also included between it and another layer or another region. And, if the part is turned over, the layer, one region, will be "below" or "beneath" the other layer, another region.

According to an aspect of the present invention, a sensor is provided. The sensor includes a reference oxygen chamber, a first chamber, a second chamber, a third chamber, a nitrogen and oxygen measuring unit and a hydrocarbon measuring unit. The nitrogen and oxygen measuring cell is located, for example, in the first chamber and/or in the second chamber and/or in the third chamber. The sensor according to the embodiment of the present invention is, for example, obtained by adding a hydrocarbon measuring unit on the basis of a traditional nitrogen and oxygen sensor.

Specifically, the first chamber communicates with the outside world through the first diffusion channel. The second chamber communicates with the first chamber through the second diffusion channel. The third chamber communicates with the second chamber through a third diffusion channel.

The nitrogen and oxygen measuring unit is used to measure the concentration of nitrogen oxides (NOx).

The hydrocarbon measuring unit is used to measure the concentration of hydrocarbons. The hydrocarbon measuring unit includes a hydrocarbon electrode and a reference electrode. A reference electrode is provided in the reference oxygen chamber. The hydrocarbon measuring unit obtains the hydrocarbon concentration according to the voltage difference between the hydrocarbon electrode and the reference electrode.

Fig. 1 shows a schematic structural diagram of a sensor according to an embodiment of the present invention. As shown in FIG. 1 , the first chamber 100 communicates with the outside world through the first diffusion channel 110 , the first chamber 100 is provided with a first pump unit, and a second chamber 100 is formed between the first chamber 100 and the reference oxygen chamber 400 . A Nernst induction unit. The first diffusion channel 110 includes a first diffusion barrier 112 and a first slit 111 .

The second chamber 200 communicates with the first chamber 100 through the second diffusion channel 210, a second pump unit is arranged in the second chamber 200, and a second energy source is formed between the second chamber 200 and the reference oxygen chamber 400. ster induction unit. The second diffusion channel 210 includes a second diffusion barrier 212 and a second slit 211 .

The third chamber 300 communicates with the second chamber 200 through the third diffusion channel 310, a third pump unit is arranged in the third chamber 300, and a third energy source is formed between the third chamber 300 and the reference oxygen chamber 400. ster induction unit. The third diffusion channel 310 includes a third diffusion barrier 312 and a third slit 311 .

The sensor also includes an upper electrode 501 and a lower electrode 502 oppositely arranged. The upper electrode 501 and the lower electrode 502 (electrodes in the auxiliary pump) are, for example, platinum electrodes, and are arranged in the second chamber 200 .

The external electrode 503 is, for example, a platinum electrode. A third electrode (measurement pump electrode) 505 is provided in the third chamber 300 .

The first electrode 504 is disposed in the first chamber 100 . The third electrode 505 is disposed in the third chamber 300 . A reference electrode 506 is disposed in the reference oxygen chamber 400 . Wherein, the first pump unit includes a common electrode 503 and a first electrode 504 ; the second pump unit includes a common electrode 503 and an upper electrode 501 or a lower electrode 502 ; the third pump unit includes a common electrode 503 and a third electrode 505 . The first Nernst sensing unit includes a reference electrode 506 and a first electrode 504; the second Nernst sensing unit includes a reference electrode 506 and an upper electrode 501 or a lower electrode 502; the third Nernst sensing unit includes a reference electrode 506 and a first electrode 502. Three electrodes 505 . Optionally, the reference oxygen chamber 400 is a closed chamber, which can avoid contamination of the reference oxygen chamber 400 by exhaust gas.

Optionally, the hydrocarbon electrode 702 is a gold (Au) electrode. The hydrocarbon electrode protective layer 701 covers the surface of the hydrocarbon electrode. The first electrode 504 is, for example, a platinum electrode. The third electrode 505 is, for example, a measuring pump platinum-rhodium electrode, and the surface of the third electrode 505 is covered with a measuring pump electrode protection layer. Optionally, the sensor further includes a heater 600 . The heater 600 is used for heating the first chamber 100 , the second chamber 200 and the third chamber 300 .

As shown in Figure 1, Ip0 is the limiting current of the main pump oxygen. Ip1 is the auxiliary pump oxygen current. Ip2 is the nitrogen and oxygen measurement current. Vref0 is the main pump Nernstian voltage. Vref1 is the Nernst voltage of the auxiliary pump. Vref2 is the measured pump Nernst voltage. Vref3 is the EMF voltage measured by hydrocarbons.

In an optional embodiment of the present invention, the sensor is applied to exhaust gas detection of a lean-burn engine. The sensor has both oxygen and nitrogen oxygen, hydrocarbon measurement capabilities. Optionally, when the excess air coefficient (lambda) is equal to 1 (set threshold), use the Nernst voltage method to measure the oxygen concentration and output the nitrogen and oxygen concentration; when lambda is greater than 1, use the limiting current method to measure the oxygen concentration and output Nitrogen and oxygen concentration; when lambda is greater than 1, the carbon and hydrogen concentration is measured and output by the electrode.

Fig. 2 shows a schematic diagram of the measurement principle of the sensor according to an embodiment of the present invention when the excess air coefficient is less than a set threshold. Fig. 3 shows a schematic diagram of the measurement principle of the sensor according to an embodiment of the present invention when the excess air coefficient is greater than a set threshold. Specifically, as shown in FIG. 2 and FIG. 3 , the sensor further includes an oxygen measurement unit and an excess air coefficient unit. The oxygen measuring unit is used to measure the oxygen concentration. The excess air ratio unit is used to obtain the excess air ratio.

When the excess air ratio is equal to the set threshold (1), the concentration of nitrogen oxides is obtained according to the Nernst voltage method. When the excess air ratio is greater than the set threshold, the concentration of nitrogen oxides is obtained according to the current between the external electrode and the third electrode.

When the excess air coefficient is greater than the set threshold, the hydrocarbon measuring unit obtains the hydrocarbon concentration according to the voltage difference between the hydrocarbon electrode and the reference electrode.

得到测量氧浓度。其中，P2为参考氧腔室的氧浓度，P1为外电极处的氧浓度，能斯特电压表征了P1的氧浓度值。Referring to Fig. 2, when the excess air coefficient is less than the set threshold (1), the Nernst voltage method is used to measure the oxygen concentration, and the measured oxygen concentration is obtained according to the oxygen concentration at the external electrode and the oxygen concentration in the reference oxygen chamber. Specifically, for example according to the formula

Obtain the measured oxygen concentration. Wherein, P2 is the oxygen concentration of the reference oxygen chamber, P1 is the oxygen concentration at the external electrode, and the Nernst voltage represents the oxygen concentration value of P1.

Referring to FIG. 3 , when the excess air ratio is greater than the set threshold (1), the measured oxygen concentration is obtained according to the current value between the first electrode and the external electrode. Specifically, a certain voltage is applied between the external electrode and the first electrode, and the generated current represents the oxygen concentration value.

Fig. 4 shows a schematic diagram of the hydrocarbon measurement principle of the sensor according to the embodiment of the present invention. Fig. 5 shows a schematic diagram of hydrocarbon concentration calibration according to an embodiment of the present invention. In an optional embodiment of the present invention, the concentration of hydrocarbons is measured by calibrating the relationship between hydrocarbons and EMF under different oxygen concentrations.

Specifically, the sensor also includes a calibration unit. The calibration unit is used to calibrate the relationship between the hydrocarbon concentration and the voltage difference between the hydrocarbon electrode and the reference electrode under different oxygen concentrations. The hydrocarbon measuring unit obtains the measured hydrocarbon concentration according to the relationship between the hydrocarbon concentration and the voltage difference between the hydrocarbon electrode and the reference electrode under different oxygen concentrations.

According to another aspect of the present invention, a combustion system (engine system) is provided. The combustion system includes a combustion (internal combustion) engine and sensors as described above. The sensor is connected to the combustion engine to detect the exhaust gas of the combustion engine. Optionally, the sensor is a multi-gas detection sensor for lean burn engine aftertreatment.

It should be noted that in this document, relational terms such as first and second etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is a relationship between these entities or operations. There is no such actual relationship or order between them. Furthermore, the term "comprises", "comprises" or any other variation thereof is intended to cover a non-exclusive inclusion such that a process, method, article, or apparatus comprising a set of elements includes not only those elements, but also includes elements not expressly listed. other elements of or also include elements inherent in such a process, method, article, or device. Without further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article or apparatus comprising said element.

Embodiments according to the present invention are described above, and these embodiments do not describe all details in detail, nor do they limit the invention to only the specific embodiments described. Obviously many modifications and variations are possible in light of the above description. This description selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can make good use of the present invention and its modification on the basis of the present invention. The invention is to be limited only by the claims, along with their full scope and equivalents.

Claims (10)

1. A sensor comprising: reference oxygen chamber; The first chamber communicates with the outside world through the first diffusion channel; a second chamber communicated with the first chamber through a second diffusion channel; a third chamber, communicated with the second chamber through a third diffusion channel; a nitrogen and oxygen measuring unit for measuring the concentration of nitrogen oxides; and Hydrocarbon measuring unit for measuring the concentration of hydrocarbons, Wherein, the hydrocarbon measuring unit includes: Hydrocarbon electrode; a reference electrode disposed in the reference oxygen chamber; The hydrocarbon measuring unit obtains the hydrocarbon concentration according to the voltage difference between the hydrocarbon electrode and the reference electrode. 2. The sensor according to claim 1, wherein a first pump unit is arranged in the first chamber, and a first Nernst sensing unit is formed between the first chamber and the reference oxygen chamber a second pump unit is arranged in the second chamber, and a second Nernst induction unit is formed between the second chamber and the reference oxygen chamber; and a second pump unit is arranged in the third chamber three pump units, a third Nernst induction unit is formed between the third chamber and the reference oxygen chamber; The sensor also includes: external electrode; a third electrode disposed in the third chamber; Excess air ratio unit for obtaining excess air ratio, Wherein, when the excess air coefficient is equal to a set threshold, the nitrogen oxide concentration is obtained according to the Nernst voltage method; When the excess air ratio is greater than a set threshold, the nitrogen oxide concentration is obtained according to the current between the external electrode and the third electrode. 3. The sensor of claim 2, wherein the sensor further comprises: a first electrode disposed in the first chamber; The upper electrode and the lower electrode arranged oppositely are arranged in the second chamber; Wherein, the first pump unit includes the outer electrode and the first electrode; the second pump unit includes the outer electrode and the upper electrode or the lower electrode; the third pump unit includes the said outer electrode and said third electrode; The first Nernst sensing unit includes the reference electrode and the first electrode; the second Nernst sensing unit includes the reference electrode and the upper electrode or the lower electrode; the third Nernst sensing unit includes the reference electrode and the upper electrode or the lower electrode; a Nernst sensing cell comprising said reference electrode and said third electrode; The reference oxygen chamber is a closed chamber. 4. The sensor of claim 1, wherein the sensor further comprises: Excess air ratio unit for obtaining excess air ratio, Wherein, when the excess air ratio is greater than a set threshold, the hydrocarbon measuring unit obtains the hydrocarbon concentration according to the voltage difference between the hydrocarbon electrode and the reference electrode. 5. The sensor according to claim 1, wherein the hydrocarbon measurement unit further comprises: The hydrocarbon electrode protective layer covers the surface of the hydrocarbon electrode. 6. The sensor of claim 1, wherein the sensor further comprises: Oxygen measurement unit for measuring oxygen concentration. 7. The sensor of claim 6, wherein the sensor further comprises: Excess air ratio unit for obtaining excess air ratio, Wherein, when the excess air coefficient is less than a set threshold, the oxygen concentration is obtained according to the oxygen concentration at the outer electrode of the sensor and the oxygen concentration of the reference oxygen chamber; When the excess air coefficient is greater than a set threshold, the oxygen concentration is obtained according to a current value between the first electrode of the sensor and the external electrode. 8. The sensor of claim 1, wherein the sensor further comprises: a calibration unit for calibrating the relationship between the hydrocarbon concentration and the voltage difference between the hydrocarbon electrode and the reference electrode under different oxygen concentrations, Wherein, the hydrocarbon measuring unit obtains the hydrocarbon concentration according to the relationship between the hydrocarbon concentration at the different oxygen concentrations and the voltage difference between the hydrocarbon electrode and the reference electrode. 9. The sensor of claim 1, wherein the sensor further comprises: a heater for heating the first chamber, the second chamber and the third chamber. 10. A combustion system comprising: combustion engines; and The sensor according to any one of claims 1-9, connected to the combustion engine to detect the exhaust gas of the combustion engine.

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