A nitrogen oxygen measurement method, a nitrogen oxygen sensor and a vehicle

Abstract

The present invention provides a nitrogen oxide measurement method, a nitrogen oxide sensor and a car, wherein the initial resistance value of the nitrogen oxide sensor is obtained, and exhaust gas is passed to the nitrogen oxide sensor, the nitrogen oxide sensor is used to absorb nitrogen oxides in the exhaust gas, and the resistance value of the nitrogen oxide sensor changes with the accumulation of the absorption amount of nitrogen oxides; when the nitrogen oxide sensor meets the preset measurement conditions, the measured resistance value of the nitrogen oxide sensor is determined; according to the measured resistance value and the initial resistance value of the nitrogen oxide sensor, the cumulative emission amount of the nitrogen oxides in the exhaust gas is determined. The present invention can determine the total amount of nitrogen oxides accumulated absorbed by the nitrogen oxide sensor over a period of time, thereby determining the total amount of nitrogen oxides accumulated emitted in the exhaust gas over a period of time, without the need to read data continuously for multiple times and calculate the cumulative value, so that the detection method of nitrogen oxides is simple and efficient. Since the cumulative emission of nitrogen oxides is measured, the problem of inaccurate measurement when the concentration of nitrogen oxides is low is avoided.

Description

Technical Field

[0001] The invention relates to the technical field of exhaust gas treatment, and in particular to a nitrogen oxygen measurement method, a nitrogen oxygen sensor and a car. Background Art

[0002] NO X (Nitrogen oxides) emissions are the main pollutants in exhaust gas emissions. With the continuous development of the concept of green development, how to control NO in exhaust gas emissions X The content of is the focus of current environmental protection management.

[0003] To ensure NO X Effective control of the content of NO in the exhaust gas requires X At present, in measuring NO X When the content of NO is detected, HC (hydrocarbons), CO (carbon monoxide), H2 (hydrogen) and other substances in the exhaust gas are first removed through oxygen reaction, and then NO (nitric oxide) is catalyzed into N2 (nitrogen) and O2 (oxygen) through the metal electrode Pt (platinum), causing the change of the current or voltage value between the electrodes. At this time, the content of NO can be determined based on the change of current or voltage value. X Therefore, although NO2 (nitrogen dioxide) is basically not catalyzed by the metal electrode Pt, the content of NO can also be used to represent NO X The content.

[0004] In the above measurement process, as long as there is exhaust gas discharge, it will cause the current or voltage value between the electrodes to change, thus affecting NO X The content of NO is fed back in real time. At this time, only the real-time NO content of the time node can be obtained at each measurement. X However, the existing emission standards are for NO X The total cumulative emissions of NO X The total cumulative emissions require continuous monitoring of the real-time NO X The steps are complicated and inefficient to measure and accumulate the content of NO at the time node. X The content of NO X When the content is low, the measurement result is inaccurate. Summary of the invention

[0005] In view of this, the present invention aims to provide a nitrogen oxide measurement method, a nitrogen oxide sensor and a vehicle to solve the problem of NO in exhaust gas. X The measurement of cumulative emissions is complicated and inefficient, and NO X The problem of inaccurate measurement results when the content is low.

[0006] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0007] Get the initial resistance value of the NOx sensor;

[0008] Passing the exhaust gas to a nitrogen oxide sensor, the nitrogen oxide sensor being used to absorb nitrogen oxides in the exhaust gas, and the resistance value of the nitrogen oxide sensor changes with the accumulation of the absorbed amount of the nitrogen oxides;

[0009] When the nitrogen oxide sensor meets the preset measurement conditions, determining the measurement resistance value of the nitrogen oxide sensor;

[0010] The accumulated emission amount of the nitrogen oxides in the exhaust gas is determined based on the measured resistance value and the initial resistance value of the nitrogen oxide sensor.

[0011] Further, one side of the nitrogen oxide sensor is a cerium oxide layer;

[0012] The obtaining of the initial resistance value of the nitrogen oxygen sensor comprises:

[0013] Obtaining a first initial resistance value of the cerium oxide layer;

[0014] The step of directing the exhaust gas to the nitrogen oxide sensor comprises:

[0015] Exhaust gas having a temperature lower than a first preset temperature is passed to the cerium oxide layer.

[0016] Further, when the nitrogen oxide sensor meets the preset measurement conditions, determining the measured resistance value of the nitrogen oxide sensor includes:

[0017] When the nitrogen oxygen sensor meets a preset measurement condition, a first measured resistance value of the cerium oxide layer is determined.

[0018] Further, the determining the cumulative emission amount of the nitrogen oxides in the exhaust gas according to the measured resistance value and the initial resistance value of the nitrogen oxide sensor includes:

[0019] determining a cumulative emission amount of nitrogen monoxide in the exhaust gas based on a first measured resistance value of the cerium oxide layer and the first initial resistance value;

[0020] The cumulative emission amount of nitrogen oxides in the exhaust gas is determined according to the cumulative emission amount of nitrogen monoxide.

[0021] Furthermore, the other side of the nitrogen oxide sensor is a barium oxide layer;

[0022] The step of obtaining the initial resistance value of the nitrogen oxide sensor further includes:

[0023] Obtaining a second initial resistance value of the barium oxide layer;

[0024] The step of directing the exhaust gas to the nitrogen oxide sensor further includes:

[0025] Exhaust gas having a temperature lower than the first preset temperature is passed to the barium oxide layer.

[0026] Further, when the nitrogen oxide sensor meets the preset measurement conditions, determining the measured resistance value of the nitrogen oxide sensor also includes:

[0027] When the nitrogen oxygen sensor meets a preset measurement condition, a second measured resistance value of the barium oxide layer is determined.

[0028] Further, the determining the cumulative emission amount of the nitrogen oxides in the exhaust gas according to the measured resistance value and the initial resistance value of the nitrogen oxide sensor also includes:

[0029] determining a cumulative emission amount of nitrogen dioxide in the exhaust gas based on a second measured resistance value of the barium oxide layer and the second initial resistance value;

[0030] The cumulative emission amount of nitrogen oxides in the exhaust gas is determined according to the cumulative emission amount of nitrogen monoxide and the cumulative emission amount of nitrogen dioxide.

[0031] Furthermore, the preset measurement condition includes at least one of the following:

[0032] The time period for which the exhaust gas is directed to the nitrogen oxide sensor reaches a preset time period;

[0033] The resistance value of the cerium oxide layer is less than or equal to a first preset resistance value;

[0034] The resistance value of the barium oxide layer is less than or equal to a second preset resistance value.

[0035] Further, the nitrogen oxide sensor further includes a heating resistor layer, the heating resistor layer is located between the cerium oxide layer and the barium oxide layer, and when the nitrogen oxide sensor meets the preset measurement conditions, after determining the measurement resistance value of the nitrogen oxide sensor, it further includes:

[0036] The heating resistor layer is heated to a second preset temperature so that the resistance value of the cerium oxide layer is reset to the first initial resistance value, and the resistance value of the barium oxide layer is reset to the second initial resistance value.

[0037] Furthermore, the first preset temperature is 200°C to 230°C.

[0038] Furthermore, the second preset temperature is 360°C to 400°C.

[0039] Furthermore, the first preset resistance value includes 200Ω~1000Ω, and the second preset resistance value includes 200Ω~1000Ω.

[0040] Compared with the prior art, the nitrogen oxide measurement method of the present invention has the following advantages:

[0041] The present invention adopts a nitrogen oxide sensor to absorb nitrogen oxides in the exhaust gas, wherein the nitrogen oxide sensor has an initial resistance value before absorbing the nitrogen oxides, and the resistance value of the nitrogen oxide sensor changes with the cumulative absorption amount of the nitrogen oxides, that is, the resistance value of the nitrogen oxide sensor is related to the cumulative absorption amount of the nitrogen oxides. At this time, when the nitrogen oxide sensor meets the preset measurement conditions, the measured resistance value corresponding to the nitrogen oxide sensor is determined, and according to the change of the measured resistance value relative to the initial resistance value, the total amount of nitrogen oxides accumulated absorbed by the nitrogen oxide sensor for a period of time can be determined, thereby determining the total amount of nitrogen oxides accumulated emitted in the exhaust gas for a period of time, without multiple continuous readings of data and calculation of cumulative values, so that the detection method of nitrogen oxides is simple and efficient. Since the cumulative emission of nitrogen oxides is measured, the problem of inaccurate measurement when the concentration of nitrogen oxides is low is avoided.

[0042] Another object of the present invention is to provide a nitrogen oxide sensor, which includes a cerium oxide layer, a barium oxide layer, and a heating resistor layer located between the cerium oxide layer and the barium oxide layer.

[0043] Another object of the present invention is to provide a vehicle having an exhaust pipe equipped with the aforementioned nitrogen oxide sensor.

[0044] The advantages of the nitrogen oxide sensor, the automobile and the above-mentioned nitrogen oxide measurement method over the prior art are the same, which will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0046] Figure 1 is a flowchart of a method for measuring nitrogen oxides provided by an embodiment of the present invention;

[0047] Figure 2 is a flowchart of another method for measuring nitrogen oxides provided by an embodiment of the present invention;

[0048] Figure 3 is a flowchart of the steps of another method for measuring nitrogen oxides provided by an embodiment of the present invention;

[0049] Figure 4is an exploded diagram of a nitrogen oxygen sensor provided by an embodiment of the present invention;

[0050] Figure 5 1 is a schematic diagram of the structure of one side of a nitrogen oxygen sensor provided by an embodiment of the present invention;

[0051] Figure 6 2 is a schematic diagram of the structure of the other side of the nitrogen oxygen sensor provided by an embodiment of the present invention.

[0052] Description of reference numerals:

[0053] 1-CeO2 layer 401, 2-first substrate 402, 3-heating resistor layer 403, 4-second substrate 404, 5-BaO layer 405, 6-CeO2 layer positive electrode lead 4011, 7-CeO2 layer negative electrode lead 4012, 8-heating resistor layer positive electrode lead 4031, 9-heating resistor layer negative electrode lead 4032, 10-BaO layer positive electrode lead 4051, 11-BaO layer negative electrode lead 4052. DETAILED DESCRIPTION

[0054] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0055] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0056] Figure 1 is a flowchart of a method for measuring nitrogen oxides provided by an embodiment of the present invention. Figure 1 As shown, the method may include:

[0057] Step 101: Obtain an initial resistance value of a nitrogen oxide sensor.

[0058] In the embodiment of the present invention, the initial resistance value of the nitrogen oxide sensor can be the nitrogen oxide sensor NO X The resistance value when the accumulated absorption is 0; or, before the exhaust gas is passed to the nitrogen oxide sensor this time, the nitrogen oxide sensor may have accumulated a certain amount of NO X At this time, the resistance value of the nitrogen oxide sensor is X The resistance value when the cumulative absorption amount is 0 is different. Therefore, the initial resistance value of the nitrogen oxide sensor may also be the resistance value before the exhaust gas is passed to the nitrogen oxide sensor this time. This embodiment of the present invention does not limit this.

[0059] Step 102 : passing the exhaust gas to a nitrogen oxide sensor, wherein the nitrogen oxide sensor is used to absorb nitrogen oxides in the exhaust gas, and a resistance value of the nitrogen oxide sensor changes with the accumulation of the absorbed amount of the nitrogen oxides.

[0060] In the present invention, waste gas refers to waste gas discharged from production and life, containing NOX The nitrogen oxide sensor is used to detect NO in the exhaust gas. X The accumulated emissions, wherein the nitrogen oxide sensor can accumulate and absorb nitrogen oxides, and the resistance value of the nitrogen oxide sensor can change with the accumulation of the nitrogen oxide absorption amount, such as the resistance value of the nitrogen oxide sensor increases with the accumulation of the nitrogen oxide absorption amount, or the resistance value of the nitrogen oxide sensor decreases with the nitrogen oxide absorption amount, and the embodiments of the present invention do not impose specific restrictions on this.

[0061] In the embodiment of the present invention, the exhaust gas is passed to the nitrogen oxide sensor by placing the nitrogen oxide sensor on the exhaust gas exhaust pipe, so that the exhaust gas passes through the nitrogen oxide sensor during the exhaust gas exhaust process, and the nitrogen oxide sensor measures NO in the exhaust gas during the exhaust gas exhaust process. X The accumulated emissions can also be measured by placing a nitrogen oxide sensor in a container that collects exhaust gas to measure the NO in the collected exhaust gas. X The accumulated emissions. X Therefore, the resistance value of the nitrogen oxide sensor can reflect the cumulative emission of NO over a period of time. X For example, during the exhaust gas discharge process through the pipeline, the NO X The accumulated absorption is a, the resistance value of the nitrogen oxide sensor is a', and the NO X The accumulated absorption is b, and the resistance value of the nitrogen oxide sensor is b', where the difference between b and a is the NO emitted from the exhaust gas to the nitrogen oxide sensor from the first minute to the second minute. X The total amount.

[0062] Step 103: When the nitrogen oxide sensor meets a preset measurement condition, determine a measurement resistance value of the nitrogen oxide sensor.

[0063] In the embodiment of the present invention, the resistance value of the nitrogen oxide sensor varies with NO X In the process of changing with the accumulation of absorption amount, when the nitrogen oxygen sensor meets the preset measurement conditions, the resistance value at that moment is used as the measured resistance value of the nitrogen oxygen sensor, wherein the preset measurement condition can be that the absorption amount of the nitrogen oxygen sensor reaches a certain value, or that the absorption time of the nitrogen oxygen sensor reaches a certain length. Those skilled in the art can set the preset measurement conditions according to specific needs, and the embodiment of the present invention does not impose specific restrictions on this.

[0064] Step 104: Determine the cumulative emission amount of the nitrogen oxides in the exhaust gas according to the measured resistance value and the initial resistance value of the nitrogen oxide sensor.

[0065] In the embodiment of the present invention, the measured resistance value is the resistance value of the nitrogen oxide sensor when it reaches the measurement condition during the process of passing exhaust gas to the nitrogen oxide sensor. At this time, the change value of the measured resistance value relative to the initial resistance value can reflect the accumulated NO absorbed during the process of passing exhaust gas to the nitrogen oxide sensor. X Therefore, the NO in the exhaust gas can be determined based on the measured resistance value and initial resistance value of the nitrogen oxide sensor. X The amount.

[0066] For example, the difference between b' and a' can reflect the difference between b and a, so that the NO emitted from the exhaust gas to the nitrogen oxide sensor from the first minute to the second minute can be determined based on the difference between b' and a'. X The total amount.

[0067] The present invention adopts a nitrogen oxide sensor to absorb nitrogen oxides in the exhaust gas, wherein the nitrogen oxide sensor has an initial resistance value before absorbing the nitrogen oxides, and the resistance value of the nitrogen oxide sensor changes with the cumulative absorption amount of the nitrogen oxides, that is, the resistance value of the nitrogen oxide sensor is related to the cumulative absorption amount of the nitrogen oxides. At this time, when the nitrogen oxide sensor meets the preset measurement conditions, the measured resistance value corresponding to the nitrogen oxide sensor is determined, and according to the change of the measured resistance value relative to the initial resistance value, the total amount of nitrogen oxides accumulated absorbed by the nitrogen oxide sensor for a period of time can be determined, thereby determining the total amount of nitrogen oxides accumulated emitted in the exhaust gas for a period of time, without multiple continuous readings of data and calculation of cumulative values, so that the detection method of nitrogen oxides is simple and efficient. Since the cumulative emission of nitrogen oxides is measured, the problem of inaccurate measurement when the concentration of nitrogen oxides is low is avoided.

[0068] Figure 2 is a flowchart of another method for measuring nitrogen oxides provided by an embodiment of the present invention. Optionally, one side of the nitrogen oxide sensor is a cerium oxide layer, such as Figure 2 As shown, the method may include:

[0069] Step 201: Obtain a first initial resistance value of the cerium oxide layer.

[0070] In the embodiment of the present invention, the first initial resistance value may be the resistance value when the cumulative absorption of NO by the CeO2 layer is 0, or may be the resistance value of the CeO2 layer before receiving the exhaust gas this time, and the embodiment of the present invention does not limit this.

[0071] Step 202: passing exhaust gas having a temperature lower than a first preset temperature to the cerium oxide layer.

[0072] In the embodiment of the present invention, one side of the nitrogen oxide sensor may be a cerium oxide (CeO2) layer. The CeO2 layer has oxygen vacancies that can inhibit electron movement, and thus has a higher resistance value. However, the CeO2 layer can react with NO XThe NO in the reaction is then accumulated and absorbed, and the reaction formula is as follows:

[0073] CeO2+3NO+2O2→Ce(NO3)3 (1)

[0074] As shown in reaction formula (1), after the CeO2 layer absorbs NO, it forms Ce(NO3)3, the lattice is destroyed, and the restriction on the movement of electrons is weakened, so that the resistance value is reduced. Therefore, the resistance value of the CeO2 layer of the nitrogen oxide sensor gradually decreases with the absorption of NO. Optionally, the thickness of the CeO2 layer can be any value between 1μm (micrometer) and 25μm, such as 1μm, 2μm, 5μm, 10μm, 15μm, 20μm, 25μm, etc.

[0075] In the embodiment of the present invention, the reaction shown in reaction formula (1) can be carried out at a certain temperature. When the temperature is higher than the temperature, the effect of the CeO2 layer on absorbing NO may be affected. Therefore, the exhaust gas below the first preset temperature can be passed to the cerium oxide layer, wherein the first preset temperature can be any temperature that ensures the efficiency of the CeO2 layer in absorbing NO, and the embodiment of the present invention does not impose any specific restrictions on this. When the temperature of the exhaust gas is higher than the first preset temperature when it is discharged, optionally, a cooling device can be provided to cool the exhaust gas first before passing it to the CeO2 layer of the nitrogen oxide sensor, or the nitrogen oxide sensor can be provided at a relatively far position to allow the exhaust gas to dissipate heat during the transmission process, thereby ensuring the absorption effect of the CeO2 layer on NO.

[0076] Step 203: When the nitrogen oxide sensor meets a preset measurement condition, determine a first measured resistance value of the cerium oxide layer.

[0077] In an embodiment of the present invention, during the process of absorbing NO, the resistance value of the CeO2 layer gradually decreases with the accumulation of NO absorption. When the nitrogen oxide sensor meets preset measurement conditions, such as absorbing a certain amount of NO, or absorbing NO for a certain period of time, it can be determined that the current resistance value of the CeO2 layer is the first measured resistance value.

[0078] Step 204 : determining the cumulative emission amount of nitrogen monoxide in the exhaust gas according to the first measured resistance value of the cerium oxide layer and the first initial resistance value.

[0079] In an embodiment of the present invention, the correspondence between the resistance change value of the CeO2 layer and the cumulative emission amount of NO in the exhaust gas can be determined by pre-measurement, and then the cumulative emission amount of nitric oxide emitted during the process of the CeO2 layer receiving the exhaust gas can be determined based on the change value of the first measured resistance value relative to the first initial resistance value.

[0080] Step 205: Determine the cumulative emission amount of nitrogen oxides in the exhaust gas according to the cumulative emission amount of nitrogen monoxide.

[0081] In the embodiment of the present invention, taking a diesel engine as an example, in the exhaust gas discharged by the diesel engine, due to NO X More than 90% of the components are NO. Therefore, the cumulative emissions of nitrogen oxides in the exhaust gas can be roughly determined based on the cumulative emissions of NO.

[0082] The present invention adopts a nitrogen oxide sensor to absorb nitrogen oxides in the exhaust gas, wherein the nitrogen oxide sensor has an initial resistance value before absorbing the nitrogen oxides, and the resistance value of the nitrogen oxide sensor changes with the cumulative absorption amount of the nitrogen oxides, that is, the resistance value of the nitrogen oxide sensor is related to the cumulative absorption amount of the nitrogen oxides. At this time, when the nitrogen oxide sensor meets the preset measurement conditions, the measured resistance value corresponding to the nitrogen oxide sensor is determined, and according to the change of the measured resistance value relative to the initial resistance value, the total amount of nitrogen oxides accumulated absorbed by the nitrogen oxide sensor for a period of time can be determined, thereby determining the total amount of nitrogen oxides accumulated emitted in the exhaust gas for a period of time, without multiple continuous readings of data and calculation of cumulative values, so that the detection method of nitrogen oxides is simple and efficient. Since the cumulative emission of nitrogen oxides is measured, the problem of inaccurate measurement when the concentration of nitrogen oxides is low is avoided.

[0083] Figure 3 is a flow chart of steps of another method for measuring nitrogen oxides provided by an embodiment of the present invention. Optionally, one side of the nitrogen oxide sensor is a cerium oxide layer, and the other side of the nitrogen oxide sensor is a barium oxide layer. Figure 3 As shown, the method may include:

[0084] Step 301: Obtain a first initial resistance value of the cerium oxide layer.

[0085] In the embodiment of the present invention, step 301 may correspond to the relevant content of step 201, and will not be described again here to avoid repetition.

[0086] Step 302: Pass exhaust gas having a temperature lower than a first preset temperature to the cerium oxide layer.

[0087] In the embodiment of the present invention, step 302 may correspond to the relevant content of step 202, and will not be described again here to avoid repetition.

[0088] Optionally, the first preset temperature is 200°C to 230°C.

[0089] In the embodiment of the present invention, a high temperature will affect the absorption effect of nitrogen oxides in the exhaust gas. Therefore, according to the temperature requirement for efficient absorption of nitrogen oxides in the exhaust gas, the first preset temperature can be any temperature between 200°C and 230°C. Optionally, the first preset temperature can be 200°C, 210°C, 220°C, 230°C, etc. When the first preset temperature is preset to 200°C, the temperature of the exhaust gas should be kept less than 200°C during the process of the exhaust gas passing through the CeO2 layer, thereby ensuring the absorption effect of the CeO2 layer on NO according to reaction formula (1).

[0090] Step 303: Obtain a second initial resistance value of the barium oxide layer.

[0091] In the embodiment of the present invention, step 303 may correspond to the relevant content of step 201, and will not be described again here to avoid repetition.

[0092] Step 304: pass exhaust gas having a temperature lower than the first preset temperature to the barium oxide layer.

[0093] In the embodiment of the present invention, the other side of the nitrogen oxide sensor may be a barium oxide (BaO) layer. The BaO layer has oxygen vacancies that can inhibit electron movement, so it has a higher resistance value. However, the BaO layer can react with NO X The NO2 in the reaction is then accumulated and absorbed, and the reaction formula is as follows:

[0094] BaO+2NO2+ 1 / 2O2→Ba(NO3)2 (2)

[0095] As shown in reaction formula (2), after the BaO layer absorbs NO2, it forms Ba(NO3)2, the lattice is destroyed, and the restriction on electron movement is weakened, thereby reducing the resistance value. Therefore, the resistance value of the BaO layer of the nitrogen oxide sensor gradually decreases with the absorption of NO2.

[0096] In an embodiment of the present invention, the nitrogen oxide sensor includes a cerium oxide layer on one side and a barium oxide layer on the other side. The cerium oxide layer and the barium oxide layer can be arranged relative to each other. Optionally, the area, shape, etc. of the cerium oxide layer and the barium oxide layer can be the same or different. At this time, the step of passing the exhaust gas to the cerium oxide layer and the barium oxide layer can be performed simultaneously or in steps. The embodiment of the present invention does not impose specific restrictions on this.

[0097] Step 305: When the nitrogen oxide sensor meets a preset measurement condition, determine a first measured resistance value of the cerium oxide layer.

[0098] In the embodiment of the present invention, step 305 may correspond to the relevant description of the aforementioned step 203, and will not be described again here to avoid repetition.

[0099] Step 306: When the nitrogen oxide sensor meets a preset measurement condition, determine a second measured resistance value of the barium oxide layer.

[0100] In an embodiment of the present invention, during the process of absorbing NO2, the resistance value of the BaO layer gradually decreases with the accumulation of NO2 absorption. When the nitrogen oxide sensor meets preset measurement conditions, such as absorbing a certain amount of NO2, or absorbing NO2 for a certain period of time, it can be determined that the current resistance value of the BaO layer is the second measured resistance value.

[0101] Optionally, the preset measurement condition includes at least one of the following:

[0102] The exhaust gas is directed to the nitrogen oxide sensor for a preset period of time.

[0103] The resistance value of the cerium oxide layer is less than or equal to a first preset resistance value.

[0104] The resistance value of the barium oxide layer is less than or equal to a second preset resistance value.

[0105] In an embodiment of the present invention, the preset measurement condition may be one or more than one. When there are multiple preset measurement conditions, the first measurement resistance value and the second measurement resistance value may be determined when all the preset measurement conditions are met, or the first measurement resistance value and the second measurement resistance value may be determined when one of the preset measurement conditions is met, or the first measurement resistance value and the second measurement resistance value may be determined when some of the preset measurement conditions are met. Optionally, the preset measurement conditions may include the time period for passing the exhaust gas to the nitrogen oxide sensor reaching a preset time period, the resistance value of the cerium oxide layer being less than the first preset resistance value, and the resistance value of the barium oxide layer being less than any one of the second preset resistance values, or at least two of the above three preset measurement conditions may be met.

[0106] In the embodiment of the present invention, since the resistance value of the CeO2 layer decreases with the cumulative absorption of NO, and the resistance value of the BaO layer decreases with the cumulative absorption of NO2, the first measured resistance value less than or equal to the first preset resistance value and / or the second measured resistance value less than or equal to the second preset resistance value can be used as the preset measurement condition, wherein the magnitude of the first preset resistance value and the second preset resistance value can be set according to the specific situation. X The composition ratios of NO and NO2 in the CeO2 layer are different. Therefore, the rates at which the resistance values ​​of the CeO2 layer and the BaO layer decrease may be different. At this time, the preset measurement condition may be that the first measured resistance value is less than the first preset resistance value or the second measured resistance value is less than the second preset resistance value, so as to avoid inaccurate measurement results caused by NO or NO2 absorption saturation. The embodiment of the present invention does not impose specific restrictions on this.

[0107] Optionally, the first preset resistance value includes 200Ω~1000Ω, and the second preset resistance value includes 200Ω~1000Ω.

[0108] In the embodiment of the present invention, the first initial resistance value of the cerium oxide layer or the second initial resistance value of the barium oxide layer varies according to the type of the oxide layer, the coating thickness, the coating area, etc. When the first initial resistance value or the second initial resistance value is NO X When the cumulative absorption amount is 0 resistance value, under a certain coating thickness and coating area, the first initial resistance value of the CeO2 layer can theoretically reach 1000Ω, and the second initial resistance value of the BaO layer can theoretically reach 1000Ω. Optionally, when the exhaust gas is automobile exhaust and the automobile accelerator pedal is depressed for more than 80% of the stroke, the resistance value when 40% of the CeO2 layer is converted into Ce(NO3)3 can theoretically reach 200Ω, and the resistance value when 40% of the BaO layer is converted into Ba(NO3)2 can theoretically reach 200Ω, that is, in the process of 40% nitrate conversion, the resistance value can theoretically decrease by 80%, and the oxide layer has a high detection efficiency for nitrogen oxides. Therefore, any resistance value between 200Ω and 1000Ω can be used as the first preset resistance value and / or the second preset resistance value. At this time, in the process of the first / second measured resistance value of the CeO2 layer / BaO layer decreasing from the first / second initial resistance value to the first / second preset resistance value, NO and NO2 can be well absorbed respectively, which is also convenient for subsequent rapid release, thereby improving NO X Cumulative emissions are measured for efficiency.

[0109] In the embodiment of the present invention, the preset time period may be the time for the surface adsorption of the CeO2 layer and the BaO layer to reach 40% from 0. When the effective areas of the CeO2 layer and the BaO layer are constant, the preset time period may be 195 seconds.

[0110] Step 307 : Determine the cumulative emission amount of nitrogen monoxide in the exhaust gas according to the first measured resistance value of the cerium oxide layer and the first initial resistance value.

[0111] In the embodiment of the present invention, step 305 may correspond to the relevant description of the aforementioned step 203, and will not be described again here to avoid repetition.

[0112] Step 308: Determine the cumulative emission amount of nitrogen dioxide in the exhaust gas according to the second measured resistance value of the barium oxide layer and the second initial resistance value.

[0113] In the embodiment of the present invention, the second initial resistance value may be the resistance value of the BaO layer before absorbing NO2, or the resistance value of the BaO layer before receiving the exhaust gas this time, and the embodiment of the present invention does not limit this. Optionally, the corresponding relationship between the resistance change value of the BaO layer and the cumulative emission amount of NO2 in the exhaust gas can be determined by pre-measurement, and then the cumulative emission amount of NO2 emitted during the process of the BaO layer receiving the exhaust gas this time can be determined based on the change value of the second measured resistance value relative to the second initial resistance value.

[0114] Step 309: Determine the cumulative emission amount of nitrogen oxides in the exhaust gas according to the cumulative emission amount of nitrogen monoxide and the cumulative emission amount of nitrogen dioxide.

[0115] In the embodiment of the present invention, NO can be determined based on the cumulative emissions of NO and NO2. X The cumulative emissions of NO are avoided by determining NO only. X The cumulative emissions of NO in the exhaust gas may cause inaccurate measurement results. When the cumulative emissions of NO or NO2 in the exhaust gas are low, NO can also be accurately measured. X Cumulative emissions in the exhaust gas.

[0116] Optionally, the nitrogen oxide sensor further includes a heating resistor layer, and the heating resistor layer is located between the cerium oxide layer and the barium oxide layer. After step 307, the method may include:

[0117] Step 310: Heat the heating resistor layer to a second preset temperature so that the resistance value of the cerium oxide layer is reset to the first initial resistance value, and the resistance value of the barium oxide layer is reset to the second initial resistance value.

[0118] In the embodiment of the present invention, in order to ensure the recycling of the nitrogen oxide sensor, the temperature of the CeO2 layer and the BaO layer can be increased so that the CeO2 layer and the BaO layer release NO and NO2 respectively, so as to detect the NO in the subsequent exhaust gas. X At this time, a heating resistor layer can be provided, and the heating resistor layer is in contact with the CeO2 layer and the BaO layer at the same time, so as to heat the CeO2 layer and the BaO layer at the same time, wherein the reaction formula of the CeO2 layer releasing NO is as follows:

[0119] Ce(NO3)3→CeO2+3NO2+ 1 / 2O2 (3)

[0120] The reaction equation for the release of NO2 from the BaO layer is as follows:

[0121] Ba(NO3)2+CO2→BaCO3+3NO2+ 1 / 2O2 (4)

[0122] Ba(NO3)2+3H2+CO2→BaCO3+2NO+2CO2 (5)

[0123] Ba(NO3)2+ 1 / 3C3H6→BaCO3+2NO+H2O (6)

[0124] It can be seen from reaction equations (4), (5) or (6) that the process of BaO layer releasing NO2 needs to be carried out under any conditions of CO2, H2 or C3H6, and the exhaust gas usually contains at least one of the above gases. When the exhaust gas does not contain the above gases, NO2 can be released. X Any of the above gases may be added during the process, and this embodiment of the present invention does not impose any specific limitation on this.

[0125] Optionally, the second preset temperature is 360°C to 400°C.

[0126] In the embodiment of the present invention, the second preset temperature can be any temperature between 360°C and 400°C. It is measured that the CeO2 layer and the BaO layer completely release NO X The temperature is between 200℃ and 400℃. The release temperature of BaO layer may be higher than that of CeO2 layer. Therefore, in order to ensure the release of NO from the oxide layer, X The second preset temperature can be set to 360°C, 370°C, 380°C, 390°C, 400°C, etc. For example, if the second preset temperature is set to 400°C, the CeO2 layer and the BaO layer are heated to 400°C by the heating resistor layer, and NO can be completed within 5 seconds. X of release.

[0127] The present invention adopts a nitrogen oxide sensor to absorb nitrogen oxides in the exhaust gas, wherein the nitrogen oxide sensor has an initial resistance value before absorbing nitrogen oxides, and the resistance value of the nitrogen oxide sensor changes with the cumulative absorption amount of nitrogen oxides, that is, the resistance value of the nitrogen oxide sensor is related to the cumulative absorption amount of nitrogen oxides. At this time, when the nitrogen oxide sensor meets the preset measurement conditions, the measured resistance value corresponding to the nitrogen oxide sensor is determined, and according to the change of the measured resistance value relative to the initial resistance value, the total amount of nitrogen oxides accumulated absorbed by the nitrogen oxide sensor for a period of time can be determined, thereby determining the total amount of nitrogen oxides accumulated emitted in the exhaust gas for a period of time, without multiple continuous readings of data and calculating the cumulative value, so that the detection method of nitrogen oxides is simple and efficient. Since the cumulative emission of nitrogen oxides is measured, the problem of inaccurate measurement when the concentration of nitrogen oxides is low is avoided; in addition, the present invention adopts two coatings to respectively measure the cumulative emissions of NO and NO2 to determine NO X The cumulative emissions of NO X The accuracy of the cumulative emissions measurement.

[0128] An embodiment of the present invention further provides a nitrogen oxygen sensor, which includes a cerium oxide layer, a barium oxide layer, and a heating resistor layer located between the cerium oxide layer and the barium oxide layer.

[0129] In the embodiment of the present invention, one side of the nitrogen oxide sensor may be a cerium oxide layer, and the other side may be a barium oxide layer, and a heating resistor layer may be included between the cerium oxide layer and the barium oxide layer. Optionally, the nitrogen oxide sensor in the embodiment of the present invention may also include only the cerium oxide layer and the heating resistor layer. The nitrogen oxide sensor can be used to achieve the following Figures 1 to 3 For any of the nitrogen oxide measurement methods shown, please refer to the above-mentioned related content and will not be repeated here.

[0130] Figure 4 is an exploded diagram of a nitrogen oxygen sensor provided by an embodiment of the present invention, such as Figure 4 As shown, the nitrogen oxygen sensor 40 may include a CeO2 layer 401, a first substrate 402, a heating resistor layer 403, a second substrate 404 and a BaO layer 405, wherein the CeO2 layer 401 also includes a CeO2 layer positive electrode lead 4011 and a CeO2 layer negative electrode lead 4012, the heating resistor layer 403 also includes a heating resistor layer positive electrode lead 4031 and a heating resistor layer negative electrode lead 4032, and the BaO layer 405 also includes a BaO layer positive electrode lead 4051 and a BaO layer negative electrode lead 4052.

[0131] In the embodiment of the present invention, the first substrate 402 and the second substrate 403 can be made of insulating pure ZrO2 (zirconium oxide), ceramics and other heat-resistant and insulating high-strength materials, and the first substrate 402 and the second substrate 403 can be bonded together to fix the heating resistor layer 403 in the middle. The CeO2 layer positive electrode lead 4011, the CeO2 layer negative electrode lead 4011, the BaO layer positive electrode lead 4051 and the BaO layer negative electrode lead 4052 can also be attached to the first substrate 402 and the second substrate 403 respectively by bonding, and the coatings of the CeO2 layer 401 and the BaO layer 405 are coated on the first substrate 402 and the second substrate 403 respectively.

[0132] Figure 5 is a schematic diagram of the structure of one side of the nitrogen oxygen sensor provided by an embodiment of the present invention, Figure 4 On the basis of Figure 5 As shown, the nitrogen oxygen sensor 40 includes a CeO 2 layer 401 , a CeO 2 layer positive electrode lead 4011 , a CeO 2 layer negative electrode lead 4012 , a heating resistor layer positive electrode lead 4031 , and a heating resistor layer negative electrode lead 4032 . Figure 6 is a schematic diagram of the structure of the other side of the nitrogen oxygen sensor provided by the embodiment of the present invention. Figure 4 On the basis of Figure 6As shown, the nitrogen oxygen sensor 40 includes a BaO layer 405, a heating resistor layer positive lead 4031, a heating resistor layer negative lead 4032, a BaO layer positive lead 4051 and a BaO layer negative lead 4052. Each lead can be independently controlled and calculated by a separate nitrogen oxygen sensor control unit, or can be integrated in other control units. The embodiment of the present invention does not impose specific restrictions on this.

[0133] In the embodiment of the present invention, Figure 4 , Figure 5 and Figure 6 For example only, the nitrogen oxygen sensor in the embodiment of the present invention does not limit the shapes of the CeO2 layer and the BaO layer.

[0134] The embodiment of the present invention also provides a vehicle, wherein the exhaust pipe of the vehicle is equipped with Figure 4 , Figure 5 and Figure 6 Any of the NOx sensors shown in .

[0135] Optionally, the nitrogen oxide sensor can be set at a position more than one meter away from the SGR (Selective Catalytic Reduction) on the exhaust pipe of the automobile, so that the exhaust gas can dissipate heat in the process of passing to the nitrogen oxide sensor, so that the temperature reaches below the first preset temperature.

[0136] The present invention adopts a nitrogen oxide sensor to absorb nitrogen oxides in the exhaust gas, wherein the nitrogen oxide sensor has an initial resistance value before absorbing the nitrogen oxides, and the resistance value of the nitrogen oxide sensor changes with the cumulative absorption amount of the nitrogen oxides, that is, the resistance value of the nitrogen oxide sensor is related to the cumulative absorption amount of the nitrogen oxides. At this time, when the nitrogen oxide sensor meets the preset measurement conditions, the measured resistance value corresponding to the nitrogen oxide sensor is determined, and according to the change of the measured resistance value relative to the initial resistance value, the total amount of nitrogen oxides accumulated absorbed by the nitrogen oxide sensor for a period of time can be determined, thereby determining the total amount of nitrogen oxides accumulated emitted in the exhaust gas for a period of time, without multiple continuous readings of data and calculation of cumulative values, so that the detection method of nitrogen oxides is simple and efficient, and because the cumulative emission of nitrogen oxides is measured, the problem of inaccurate measurement when the concentration of nitrogen oxides is low is avoided.

[0137] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for measuring nitrogen oxides, characterized in that: The method comprises: Get the initial resistance value of the NOx sensor; Passing the exhaust gas to a nitrogen oxide sensor, the nitrogen oxide sensor being used to absorb nitrogen oxides in the exhaust gas, and the resistance of the nitrogen oxide sensor changes with the accumulation of the absorbed amount of the nitrogen oxides; When the nitrogen oxide sensor meets the preset measurement conditions, determining the measurement resistance value of the nitrogen oxide sensor; determining a cumulative emission amount of the nitrogen oxides in the exhaust gas according to a measured resistance value and an initial resistance value of the nitrogen oxide sensor; One side of the nitrogen oxygen sensor is a cerium oxide layer; The other side of the nitrogen oxygen sensor is a barium oxide layer; The nitrogen oxygen sensor also includes a heating resistor layer; Wherein, obtaining the initial resistance value of the nitrogen oxide sensor includes: Obtaining a first initial resistance value of the cerium oxide layer; The step of directing the exhaust gas to the nitrogen oxide sensor comprises: Passing exhaust gas with a temperature value lower than a first preset temperature value to the cerium oxide layer; When the nitrogen oxide sensor meets a preset measurement condition, determining the measured resistance value of the nitrogen oxide sensor includes: When the nitrogen oxygen sensor meets a preset measurement condition, determining a first measured resistance value of the cerium oxide layer; The step of determining the cumulative emission amount of the nitrogen oxides in the exhaust gas according to the measured resistance value and the initial resistance value of the nitrogen oxide sensor comprises: determining a cumulative emission amount of nitrogen monoxide in the exhaust gas based on a first measured resistance value of the cerium oxide layer and the first initial resistance value; The cumulative emission amount of nitrogen oxides in the exhaust gas is determined according to the cumulative emission amount of nitrogen monoxide.

2. The method according to claim 1, characterized in that The step of obtaining the initial resistance value of the nitrogen oxide sensor further includes: Obtaining a second initial resistance value of the barium oxide layer; The step of directing the exhaust gas to the nitrogen oxide sensor further includes: passing exhaust gas having a temperature lower than the first preset temperature to the barium oxide layer; When the nitrogen oxide sensor meets the preset measurement conditions, determining the measured resistance value of the nitrogen oxide sensor also includes: When the nitrogen oxygen sensor meets the preset measurement conditions, determining a second measured resistance value of the barium oxide layer; The method of determining the cumulative emission amount of the nitrogen oxides in the exhaust gas according to the measured resistance value and the initial resistance value of the nitrogen oxide sensor further includes: determining a cumulative emission amount of nitrogen dioxide in the exhaust gas based on a second measured resistance value of the barium oxide layer and the second initial resistance value; The cumulative emission amount of nitrogen oxides in the exhaust gas is determined according to the cumulative emission amount of nitrogen monoxide and the cumulative emission amount of nitrogen dioxide.

3. The method according to claim 2, characterized in that The preset measurement condition includes at least one of the following: The time period for which the exhaust gas is directed to the nitrogen oxide sensor reaches a preset time period; The resistance value of the cerium oxide layer is less than or equal to a first preset resistance value; The resistance value of the barium oxide layer is less than or equal to a second preset resistance value.

4. The method according to claim 2, characterized in that: The heating resistor layer is located between the cerium oxide layer and the barium oxide layer. When the nitrogen oxide sensor meets the preset measurement conditions, after determining the measurement resistance value of the nitrogen oxide sensor, the method further includes: The heating resistor layer is heated to a second preset temperature so that the resistance value of the cerium oxide layer is reset to the first initial resistance value, and the resistance value of the barium oxide layer is reset to the second initial resistance value.

5. The method according to any one of claims 1 or 2, characterized in that: The first preset temperature is 200°C~230°C.

6. The method according to claim 4, characterized in that The second preset temperature is 360°C~400°C.

7. The method according to claim 3, characterized in that The first preset resistance value is any resistance value between 200Ω and 1000Ω, and the second preset resistance value is any resistance value between 200Ω and 1000Ω.

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