CN114046197B

CN114046197B - Method and device for treating waste gas and readable storage medium

Info

Publication number: CN114046197B
Application number: CN202111183492.9A
Authority: CN
Inventors: 张军; 张娟; 李云霞; 王震华; 葛浩
Original assignee: Weichai Power Co Ltd; Weifang Weichai Power Technology Co Ltd
Current assignee: Weichai Power Co Ltd; Weifang Weichai Power Technology Co Ltd
Priority date: 2021-10-11
Filing date: 2021-10-11
Publication date: 2023-03-21
Anticipated expiration: 2041-10-11
Also published as: CN114046197A

Abstract

The application discloses a method and a device for treating waste gas and a readable storage medium, which are applied to a national six post-treatment system and solve the problems of short regeneration period of DPF, increased urea crystallization amount and reduced performance of SCR catalyst, which cause the reduction of the overall performance of the national six post-treatment system. The method comprises the following steps: determining that the waste gas is in an abnormal state after passing through a national six post-treatment system; wherein the abnormal state indicates that the exhaust gas has passed through the national six after-treatment system at a rate below a rate threshold and/or a NOx content above a pollutant threshold; in response to the abnormal state, determining to take a warming measure for a national six aftertreatment system; wherein the temperature-raising measure comprises continuously maintaining the national six after-treatment system at the target temperature until the exhaust gas is treated by the national six after-treatment system, the emission rate is not lower than the rate threshold, and the NOx content is not higher than the pollutant threshold.

Description

Method and device for treating waste gas and readable storage medium

Technical Field

The present disclosure relates to the field of mechanical technologies, and in particular, to a method and an apparatus for treating exhaust gas, and a readable storage medium.

Background

An aftertreatment system is disposed downstream of the diesel engine for treating exhaust gas emitted by the diesel engine. Aiming at the national emission standard, the waste gas is treated by a post-treatment system and needs to meet the national emission standard. With the continuous emission of diesel engine exhaust, the following phenomena occur in the six aftertreatment systems of state: particulate matter (carbon particles) trapped by a particulate matter trap (DPF) gradually accumulates, urea crystallization amount at the inlet side of a rear selective catalytic conversion device (SCR) is increased, and SCR catalyst in the SCR is poisoned by sulfur. Wherein, the increase of the carbon loading of the DPF can cause the active regeneration period of the DPF to be shortened, and further the trapping effect of the DPF on particulate matters (carbon granules) in the exhaust gas is hindered; the increase of the urea crystallization amount can cause the aging of an after-treatment system, cause the appearance of potential safety hazards and influence the treatment of NOx in the waste gas; sulfur poisoning (sulfates) of SCR catalysts can cause the catalyst to lose catalytic activity, thereby hindering the treatment of NOx in the exhaust gas in SCR.

In view of the above, it is necessary to increase the temperatures in the DPF and the SCR to reduce the carbon loading and the urea crystallization amount, and to reduce the sulfate in the SCR to improve the catalytic efficiency of the SCR catalyst, thereby extending the active regeneration period of the DPF, the life of the post-treatment system, and the life of the SCR catalyst.

In the prior art, by improving the device of the national six post-processing system, the system can identify the temperature difference between the target temperature and the post-processing system in time and heat the national six post-processing system to the target temperature. An accurate and efficient method is lacked for judging that the national six post-treatment system needs to be subjected to temperature rise treatment, the DPF regeneration period of the national six post-treatment system is increased through temperature rise, the urea crystallization amount is reduced, and the performance of an SCR catalyst is improved, so that the overall performance of the national six post-treatment system is improved.

Disclosure of Invention

The invention provides a method and a device for treating waste gas and a readable storage medium, which are applied to a national six post-treatment system and used for solving the problem of the overall performance reduction of the national six post-treatment system caused by the increase of DPF carbon loading capacity and SCR urea crystallization and the performance reduction of an SCR catalyst.

In a first aspect, to solve the above technical problem, the present invention provides a method for treating exhaust gas, which is applied to a national sixth aftertreatment system, and the method includes:

determining that the waste gas is in an abnormal state after passing through a national six post-treatment system; wherein the abnormal state indicates that the exhaust gas has passed through the national six after-treatment system at a rate below a rate threshold and/or a level of NOx above a pollutant threshold;

in response to the abnormal state, determining to take warming measures for a national six after-treatment system; wherein the temperature-raising measure includes continuously maintaining the six country post-treatment system at the target temperature until the exhaust gas passes through the six country, the emission rate is not lower than the rate threshold, and the NOx content is not higher than the pollutant threshold.

Through the operation, a temperature rise measure can be determined to be taken for the six-country aftertreatment system based on the carbon loading amount of the DPF, the crystallization amount of the SCR urea and the catalytic efficiency of the SCR, and the purpose of improving the performance of the six-country aftertreatment system is achieved through temperature rise.

In one possible implementation manner, the abnormal state includes a first abnormal state and a second abnormal state; wherein the first abnormal state indicates that the exhaust gas enters a first abnormal range after passing through the sixth aftertreatment system and the emission rate is lower than a first rate threshold, and/or the content of NOx is higher than a first pollutant threshold; the second abnormal state indicates that the exhaust gas enters a second abnormal range after passing through the national six post-treatment system and the discharge rate is lower than a second rate threshold value and/or the content of NOx is higher than a second pollutant threshold value; the second rate threshold is less than the first rate threshold, the second contamination threshold is greater than the first contamination threshold;

said determining to take warming action for a six post-processing system in response to said abnormal condition comprises:

in response to the first abnormal state, determining to take a first-level warming measure for a national sixth aftertreatment system; wherein the first-level temperature rise measure indicates that the national six post-processing system is continuously kept at a first-level target temperature within a set time range;

in response to the second abnormal state, determining to take a secondary heating measure for a national sixth aftertreatment system; wherein the secondary heating measures indicate that the national six after-treatment system is continuously maintained at the secondary target temperature until the exhaust gas passes through the national six after-treatment system, the emission rate is not lower than the first rate threshold, and the NOx content is not higher than the first pollutant threshold; the primary target temperature is lower than the secondary target temperature.

By setting the first-stage temperature rising measure and the second-stage temperature rising measure, the temperature and the temperature maintaining time in the national six post-treatment system are controlled within a reasonable range, so that the national six post-treatment system can be prevented from being aged when entering a high-temperature state frequently.

One possible implementation manner of determining that the exhaust gas is in an abnormal state after passing through the national six post-treatment system includes:

determining the carbon loading capacity of DPF, the crystallization amount of SCR urea and the catalytic efficiency of SCR in the post-treatment system of the national six; wherein the DPF carbon loading indicates an exhaust rate of the exhaust after treatment by the national six after-treatment system; the SCR urea crystallization amount and the SCR catalytic efficiency indicate the content of NOx in the exhaust gas after passing through a national six post-treatment system;

determining abnormal values corresponding to at least one parameter of DPF carbon loading, SCR urea crystallization and SCR catalytic efficiency;

if the abnormal value exceeds the corresponding low-temperature threshold value, determining that the exhaust gas is in the first abnormal state after passing through a national six post-treatment system;

and if the abnormal value exceeds the corresponding high-temperature threshold value, determining that the exhaust gas is in the second abnormal state after passing through the national six post-treatment system.

The DPF carbon loading capacity, the SCR urea crystallization amount and the SCR catalytic efficiency are used as parameters for representing whether the waste gas meets the national six emission standards after passing through the national six post-treatment system, so that the aim of accurate judgment can be fulfilled.

One possible implementation manner, the determining that the exhaust gas is in the second abnormal state after passing through the sixth aftertreatment system, further includes:

detecting the ammonia leakage times of the national six post-treatment system within a set time range;

when the temperature rise in the SCR of the national six post-treatment system exceeds a temperature threshold value, dividing the SCR temperature change process into a plurality of temperature intervals;

calculating the SCR catalytic efficiency of the plurality of temperature intervals and the change rate of the SCR catalytic efficiency of the preselected temperature intervals;

comparing the ammonia leakage frequency within the set time range with an ammonia leakage frequency threshold value; comparing the SCR catalytic efficiency of a plurality of temperature intervals in the SCR with the SCR catalytic efficiency range threshold corresponding to each temperature interval; comparing the rate of change of the SCR catalytic efficiency of the preselected temperature interval to an SCR catalytic efficiency rate of change threshold;

and when the ammonia leakage frequency exceeds an ammonia leakage frequency threshold value within a set time range, the SCR catalytic efficiency of each temperature interval in the SCR is within the SCR catalytic efficiency range threshold value corresponding to each temperature interval, and the SCR catalytic efficiency change rate of the preselected temperature interval is lower than the SCR catalytic efficiency change rate threshold value, determining that the exhaust gas is in the second abnormal state after passing through the national and international post-treatment systems.

One possible implementation manner of the present invention, the comparing SCR catalytic efficiency of a plurality of temperature intervals in the SCR with the SCR catalytic efficiency range threshold corresponding to each temperature interval includes:

acquiring the time of the SCR in the plurality of temperature intervals respectively and the proportion of the time of the plurality of temperature intervals to the total time; wherein, the total time refers to the sum of the time of each temperature interval in the SCR;

comparing the time of the plurality of temperature intervals with the time threshold of each temperature interval respectively; comparing the proportion of the time of the plurality of temperature intervals to the total time with the time ratio threshold corresponding to each temperature interval respectively;

and comparing the SCR catalytic efficiency of each temperature interval in the SCR with the SCR catalytic efficiency range threshold corresponding to each temperature interval until the time of each temperature interval exceeds the time threshold of each temperature interval and the proportion of the time of each temperature interval to the total time exceeds the time ratio threshold corresponding to each temperature interval.

In a second aspect, the present invention provides an exhaust gas treatment device, which is applied to a national six post-treatment system, and comprises:

a determination unit: the device is used for determining that the waste gas is in an abnormal state after passing through the national six post-treatment system; wherein the abnormal state indicates that the exhaust gas has passed through the national six after-treatment system at a rate below a rate threshold and/or a level of NOx above a pollutant threshold;

a temperature increasing unit: the system is used for responding to the abnormal state and determining that a temperature rise measure is taken for the national six post-processing system; wherein the temperature-raising measure comprises continuously maintaining the national six after-treatment system at the target temperature until the exhaust gas is treated by the national six after-treatment system, the emission rate is not lower than the rate threshold, and the NOx content is not higher than the pollutant threshold.

In one possible implementation, the abnormal state includes a first abnormal state and a second abnormal state; wherein the first abnormal state indicates that the exhaust gas enters a first abnormal range after passing through the sixth aftertreatment system and the emission rate is lower than a first rate threshold, and/or the content of NOx is higher than a first pollutant threshold; the second abnormal state indicates that the exhaust gas enters a second abnormal range after passing through the national six post-treatment system and the discharge rate is lower than a second rate threshold value and/or the content of NOx is higher than a second pollutant threshold value; the second rate threshold is less than the first rate threshold, the second contamination threshold is greater than the first contamination threshold;

the temperature rising unit is specifically used for responding to the first abnormal state and determining that first-level temperature rising measures are taken for the national six post-processing system; wherein the first-level temperature rise measure indicates that the national six post-processing system is continuously kept at a first-level target temperature within a set time range; in response to the second abnormal state, determining to take a secondary heating measure for a national sixth aftertreatment system; wherein the secondary heating measures indicate that the national six after-treatment system is continuously maintained at the secondary target temperature until the exhaust gas passes through the national six after-treatment system, the emission rate is not lower than the first rate threshold, and the NOx content is not higher than the first pollutant threshold; the primary target temperature is lower than the secondary target temperature.

In a possible implementation manner, the determining unit is further configured to determine the carbon loading of the DPF, the crystallization amount of the SCR urea, and the catalytic efficiency of the SCR in the six aftertreatment systems; wherein the DPF carbon loading indicates an exhaust rate of the exhaust after treatment by the national six after-treatment system; the SCR urea crystallization amount and the SCR catalytic efficiency indicate the content of NOx in the exhaust gas after passing through a national six post-treatment system; determining abnormal values corresponding to at least one parameter of DPF carbon loading capacity, SCR urea crystallization capacity and SCR catalytic efficiency; if the abnormal value exceeds the corresponding low-temperature threshold value, determining that the exhaust gas is in the first abnormal state after passing through a national six post-treatment system; and if the abnormal value exceeds the corresponding high-temperature threshold value, determining that the exhaust gas is in the second abnormal state after passing through the national six post-treatment system.

In a possible implementation manner, the determining unit is further configured to detect the number of times of ammonia leakage of the six-country aftertreatment system within a set time range; when the temperature rise in the SCR of the national six post-treatment system exceeds a temperature threshold, dividing the SCR temperature change process into a plurality of temperature intervals; calculating the SCR catalytic efficiency of the plurality of temperature intervals and the change rate of the SCR catalytic efficiency of the preselected temperature intervals; comparing the ammonia leakage frequency within the set time range with an ammonia leakage frequency threshold value; comparing the SCR catalytic efficiency of a plurality of temperature intervals in the SCR with the SCR catalytic efficiency range threshold corresponding to each temperature interval; comparing the rate of change of SCR catalytic efficiency for the preselected temperature interval to an SCR catalytic efficiency rate of change threshold; and when the ammonia leakage frequency exceeds an ammonia leakage frequency threshold value within a set time range, the SCR catalytic efficiency of each temperature interval in the SCR is within the SCR catalytic efficiency range threshold value corresponding to each temperature interval, and the SCR catalytic efficiency change rate of the preselected temperature interval is lower than the SCR catalytic efficiency change rate threshold value, determining that the exhaust gas is in the second abnormal state after passing through the national and international post-treatment systems.

In a third aspect, the present application provides a readable storage medium comprising:

a memory for storing a plurality of data to be transmitted,

the memory is configured to store instructions that, when executed by the processor, cause an apparatus comprising the readable storage medium to perform a method according to the first aspect and any one of the implementations.

Drawings

FIG. 1 is a schematic diagram of a prior art six post-processing system in China;

FIG. 2 is a flow chart of a method of exhaust treatment provided herein;

FIG. 3 is a flow chart of a method provided herein for determining an abnormal state of exhaust gas after passing through a six-state aftertreatment system based on primary reference parameters;

FIG. 4 is a flow chart provided herein for determining a first level of warming action to be taken with respect to a sixth aftertreatment system in response to a first abnormal condition;

FIG. 5 is a flow chart provided herein for determining a secondary heating action to be taken with respect to a six post-processing system in response to a second exception condition;

fig. 6 is a schematic structural diagram of an exhaust gas treatment device provided by the present application.

Detailed Description

In order to solve the problem that the overall performance of the national six after-treatment system is reduced due to the fact that urea is crystallized, the DPF regeneration period is short, and the performance of an SCR catalyst is reduced in the national six after-treatment system, the embodiment of the application provides an exhaust gas treatment method, which is applied to the national six after-treatment system: according to the abnormal state of the waste gas after passing through the national six post-treatment system, the temperature rise measures adopted by the national six post-treatment system are determined, and the problem of performance reduction of the national six post-treatment system caused by increase of carbon loading of the DPF and crystallization of the SCR urea and performance reduction of the SCR catalyst is solved by raising the temperature of the national six post-treatment system.

The technical terms used in the present application are explained first below:

and (4) national six emission standards: the automobile air pollution control system refers to the automobile pollutant emission standard in the sixth stage of China, and is a standard established for preventing and controlling automobile pollution emission and improving the environmental air quality.

A post-processing system: an apparatus mounted downstream of an engine for abating pollutants in exhaust gas from the engine.

Six post-processing systems in state: refers to an after-treatment system which can discharge pollutants meeting the national emission standard of six. Fig. 1 is a schematic structural diagram of a six-country post-processing system. As can be seen from fig. 1: the six-country aftertreatment system mainly comprises an oxidation catalytic converter (DOC), a particulate matter trap (DPF) and a post-positioned selective catalytic conversion device (SCR). And a urea nozzle DM is arranged between the DPF and the SCR, and the DM sprays urea to enter the SCR to serve as a reducing agent to react with NOx in the exhaust gas, so that the NOx in the exhaust gas meets the emission standard of the national six when the NOx is discharged out of the national six after-treatment system. In ChinaIn a six-process system, there are 2 Nox sensors, NO _X1 Before DOC, NO _X2 Located after the SCR.

Particulate matter trap (Diesel Particulate Filter, DPF): when the amount of the trapped particulate matter reaches a certain degree, passive regeneration or active regeneration is needed, so that the trapping capacity of the DPF on the particulate matter is recovered. Wherein, the active regeneration means that the temperature in the trap is raised by using external energy to ignite and burn particles. Passive regeneration refers to the use of fuel additives or catalysts to lower the ignition temperature of the particulates so that the particulates can ignite and burn at normal engine exhaust temperatures.

Oxidation catalytic converter (Diesel Oxide Catalyst, DOC): before the DPF, it is used to oxidize part of the exhaust gas of the engine: oxidation of NO to NO ₂ Oxidation of CO to CO ₂ Oxidation of CH to CO ₂ And water. Meanwhile, the temperature of the exhaust gas of the engine is raised, and the normal work of the DPF and the SCR is assisted.

Post-selective Catalytic conversion device (SCR): the SCR catalyst is placed in the reaction kettle and can promote the reaction of the reducing agent and NOx and inhibit the non-selective oxidation reaction of the reducing agent and oxygen. When engine exhaust enters the SCR, NOx in the exhaust is removed by a reducing agent.

Urea crystallization: currently, NH is commonly utilized in SCR ₃ As a reductant, NH may be obtained by injecting an aqueous urea solution prior to SCR ₃ . However, the temperature of the urea aqueous solution injection is not consistent with the temperature of the pipe wall, so that the urea crystallization phenomenon is easy to occur. Urea crystallization can create backpressure, corroding the material, thereby reducing the life and performance of the SCR system. Aiming at urea crystallization, the urea crystallization can be promoted to be heated and decomposed by increasing the temperature, so that the aim of reducing or eliminating the urea crystallization is fulfilled.

Sulfur poisoning: exhaust gas produced by an engine contains sulfur oxides. The oxide of sulfur can form sulfate in the copper-based SCR to block small holes, so that the catalytic efficiency of the SCR catalyst on NOx is reduced; or, oxides of Sulfur (SO) ₂ And SO ₃ ) Compete with NOx for adsorption, and reduce NOx of SCR catalystThe catalytic efficiency of (2). Therefore, the phenomenon that a certain amount of sulfate is generated in SCR to cause deactivation of the SCR catalyst is called sulfur poisoning. Aiming at the sulfur poisoning phenomenon, desulfurization treatment needs to be carried out on the SCR catalyst to recover the activity of the SCR catalyst.

In order to better understand the technical solutions of the present application, the following detailed descriptions of the technical solutions of the present application are provided with the accompanying drawings and the specific embodiments, and it should be understood that the specific features of the embodiments and the examples of the present application are detailed descriptions of the technical solutions of the present application, and are not limitations of the technical solutions of the present application, and the technical features of the embodiments and the examples of the present application may be combined with each other without conflict.

Referring to fig. 2, an embodiment of the present application provides a method for treating exhaust gas, which is applied to a six-country aftertreatment system, and determines to take a temperature raising measure for the six-country aftertreatment system based on that the exhaust gas is in an abnormal state through the six-country aftertreatment system, so as to solve the problem of overall performance degradation of the six-country aftertreatment system caused by a short DPF regeneration period, increased urea crystals, and performance degradation of an SCR catalyst, and the method includes the following treatment processes:

step 201: and determining that the waste gas is in an abnormal state after passing through the national six post-treatment system.

Wherein the abnormal state indicates that the exhaust gas has an emission rate below a rate threshold and/or a NOx content above a pollutant threshold after passing through the six aftertreatment system.

The abnormal state may include a first abnormal state and a second abnormal state. Wherein the first abnormal state indicates that the exhaust gas after passing through the sixth aftertreatment system has an emission rate below a first rate threshold and/or a NOx content above a first pollutant threshold, entering a first abnormal range. And the second abnormal state indicates that the exhaust gas enters a second abnormal range after passing through the national six after-treatment system and the emission rate is lower than a second rate threshold, and/or the content of NOx is higher than a second pollutant threshold. The second rate threshold is less than the first rate threshold, and the second contamination threshold is greater than the first contamination threshold.

Referring to fig. 3, in the embodiment of the present application, the main reference parameters of whether the exhaust gas after treatment meets the national emission standard include DPF carbon loading, SCR urea crystallization amount, and SCR catalytic efficiency, and the following method for determining that the exhaust gas after passing through the national emission standard is in an abnormal state based on the main reference parameters is specifically described.

Step 301: and determining the carbon loading of the DPF, the crystallization amount of SCR urea and the catalytic efficiency of SCR.

The DPF carbon loading capacity indicates the content of particulate matters in the exhaust gas treated by the six-stage aftertreatment system; and the SCR urea crystallization amount and the SCR catalytic efficiency indicate the content of NOx in the exhaust gas after passing through the six aftertreatment systems.

The following is a detailed description of calculating DPF carbon loading, SCR urea crystallization, and SCR catalytic efficiency.

1. Determination of DPF carbon loading

The DPF carbon loading is calculated from a differential pressure or carbon loading model.

Specifically, the volumetric flow rate of the engine exhaust gas is acquired. And reading the readings of the pressure gauges on the inlet side and the outlet side of the DPF to obtain the pressure difference of the DPF. And inquiring a carbon loading table according to the volume flow of the exhaust gas and the pressure difference to determine the carbon loading of the DPF.

In addition, the working conditions (rotating speed, torque and exhaust gas oxygen concentration) of the engine can be input into a physical model, and the carbon loading of the DPF can be obtained according to the physical model.

2. Determination of SCR Urea Crystal quantity

And determining the urea crystallization amount by multiplying the overspray urea amount by the crystallization coefficient.

The crystallization coefficient indicates a degree of easy crystallization of the urea aqueous solution. For example, when the crystallization coefficient is 1, it represents percent crystallization of urea.

The higher the temperature, the more readily the aqueous urea solution crystallizes. And the increase of the crystallization amount of the urea aqueous solution also makes the urea easier to crystallize. Therefore, in determining the crystallization coefficient, it is necessary to refer to the temperature, the exhaust gas flow rate, and the urea crystallization amount at the previous time.

The urea solutions of different concentrations have different crystal boundary injection amounts, i.e., urea starts to crystallize when the urea injection amount reaches the crystal boundary injection amount. Therefore, the over-injected urea amount refers to an urea injection amount in which the actual injected urea amount exceeds the crystal boundary injection amount.

3. Determining SCR catalytic efficiency

SCR catalytic efficiency means that in SCR the reducing agent undergoes an oxidation-reduction reaction with NOx, which is converted to N ₂ The conversion efficiency of (a). Using downstream NO _x2 With upstream NO _x1 Calculating the catalytic efficiency of NOx:

in the embodiment of the application, the SCR catalytic efficiency refers to the catalytic efficiency of the SCR catalyst.

Step 302: and determining abnormal values corresponding to at least one parameter of DPF carbon loading, SCR urea crystallization amount and SCR catalytic efficiency.

And respectively carrying out stage state division aiming at the DPF carbon loading capacity, the SCR urea crystallization amount and the SCR catalytic efficiency, and determining abnormal values. Wherein the outlier indicates particulate matter of the exhaust after the six national aftertreatment systems, and/or NOx exceeding the six national emission standards.

The carbon loading capacity of the DPF, the crystallization amount of the SCR urea and the catalytic efficiency of the SCR are divided into stages, and the carbon loading capacity of the DPF, the crystallization amount of the SCR urea and the state of the catalytic efficiency of the SCR can be determined by respectively referring to respective preset look-up tables (Curve, CUR). Wherein, the state can be represented by using the effective number corresponding to the interval in the table lookup, and the effective number is an abnormal value. Note that, regarding the DPF carbon amount and the SCR urea crystal amount, the higher the corresponding abnormal value. For the SCR catalytic efficiency, the lower the SCR catalytic efficiency, the higher the corresponding abnormal value.

For example, the DPF carbon loading is determined to be 1.3g/L according to step 101. The CUR for DPF carbon loading is shown in table 1.

TABLE 1

Interval(s)	0-1.2g/L	1.2-2.0g/L	2.0-3.0g/L	3.0-4.0g/L	4.0-5.0g/L
						Significant digits	0	1	2	3	4

When the stage state to which the DPF carbon loading amount of 1.3g/L belongs to the (1.2-2.0 g/L) interval, the significand corresponding to 1.3g/L is 1, that is, the abnormal value of the DPF carbon loading amount is 1, as can be seen from the query of the CUR table 1 corresponding to the DPF carbon loading amount.

Step 303: if the abnormal value exceeds the low-temperature threshold value, determining that the waste gas is in the first abnormal state after passing through a national six post-treatment system; and if the abnormal value exceeds the high-temperature threshold value, determining that the exhaust gas is in the second abnormal state after passing through the national six post-treatment system.

Wherein, the low temperature threshold and the high temperature threshold are obtained by calibration when each batch of diesel oil is applied to the diesel engine.

The exhaust gas treatment generally undergoes the following conditions. As the diesel engine begins to exhaust, the six aftertreatment in china begins to operate, treating the exhaust. The DPF collects particulate matter in exhaust gas, the particulate matter being mainly composed of carbon particles; meanwhile, in the SCR, NOx in the exhaust gas is promoted to react with ammonia in the urea under the catalysis of an SCR catalyst, and in the stage, after the exhaust gas passes through a national six post-treatment system, the emission rate is not lower than a first rate threshold, and the content of NOx is not higher than a first pollutant threshold. However, with the operation of the six-country aftertreatment system, more and more particulate matters in the exhaust gas are trapped in the DPF, so that the subsequent trapping of the particulate matters in the exhaust gas is influenced, and the exhaust emission rate is lower and lower; the crystallization of urea at the SCR inlet results in less and less urea entering the SCR, while the SCR catalyst is gradually poisoned by sulfur, resulting in the SCR not being able to treat NOx in the exhaust gas in time before the exhaust gas is discharged. The above factors will cause the emission rate of the exhaust gas after passing through the sixth aftertreatment system to fall below the first rate threshold, and/or the NOx content to be above the first pollutant threshold; i.e. an abnormal state. If the waste gas cannot be treated in time, the emission rate of the waste gas after passing through the national six post-treatment system is lower and is reduced to be lower than a second rate threshold, and simultaneously the content of NOx is higher and is increased to be higher than a second pollutant threshold. The embodiment of the application further divides the abnormal state into a first abnormal state and a second abnormal state, and indicates that the discharge rate of the exhaust gas passing through the national six after-treatment system is lower than a first rate threshold value and a second rate threshold value, and the NOx content exceeds a first pollutant threshold value and a second pollutant threshold value.

Aiming at the condition that any abnormal value corresponding to the first abnormal state, the DPF carbon loading capacity, the SCR urea crystallization amount and the SCR catalytic efficiency exceeds a corresponding low-temperature threshold value, the exhaust gas can be determined to be in the first abnormal state after passing through the national sixth aftertreatment system. In particular, abnormal values corresponding to DPF carbon loading, SCR urea crystallization and SCR catalytic efficiency can be multiplied, and if the product exceeds a corresponding low-temperature threshold value, the exhaust gas can be determined to be in the first abnormal state through the national six post-treatment system.

In the same way, aiming at the second abnormal state, the second abnormal state can be determined after the exhaust gas passes through the national six post-treatment system, if any abnormal value corresponding to the DPF carbon loading amount, the SCR urea crystallization amount and the SCR catalytic efficiency exceeds the corresponding high-temperature threshold value. Where the low temperature threshold is lower than the high temperature threshold.

It is to be noted that, since the influence of the SCR catalyst sulfur poisoning on the exhaust gas treatment by the six after-treatment system is large, when it is determined that the SCR catalyst sulfur poisoning is serious, the second abnormal state may be determined. The sulfur poisoning of the SCR catalyst may cause a reduction in the catalytic efficiency of the SCR catalyst, and an ammonia slip phenomenon, and the determination of the severity of the sulfur poisoning of the SCR catalyst will be described in detail below using the SCR catalytic efficiency and the ammonia slip.

1. And detecting the ammonia leakage frequency of the national six post-treatment system within a set time range. And comparing the ammonia leakage frequency in the set time range with an ammonia leakage frequency threshold value.

The method of detecting ammonia slip includes: detecting dragging and monitoring NOx content.

The drag detection refers to the engine being in a drag state and testing the NOx content downstream of the SCR. The reverse towing state refers to a state in which the engine stops operating and no exhaust gas is generated. Therefore, when a high NOx content is detected on the SCR outlet side in the drag detection, it is considered that ammonia slip is caused.

NOx content monitoring refers to comparing an upstream NOx sensor indication to a downstream SCR outlet side NOx sensor indication. If the downstream NOx sensor reading is significantly higher than the downstream SCR outlet side NOx sensor reading, it is considered that ammonia slip is present.

2. The process of the SCR catalyst poisoning is a process which gradually changes and becomes more serious, and when the temperature in the SCR of the national six post-treatment system rises and exceeds a temperature threshold, the SCR temperature change process can be divided into a plurality of temperature intervals. Then acquiring the time of the SCR in the plurality of temperature intervals respectively and the proportion of the time of the plurality of temperature intervals to the total time; wherein the total time refers to the sum of the time of each temperature interval in the SCR. Then, comparing the time of the plurality of temperature intervals with the time threshold of each temperature interval respectively; and comparing the proportion of the time of the plurality of temperature intervals to the total time with the time ratio threshold corresponding to each temperature interval. And comparing the SCR catalytic efficiency of each temperature interval in the SCR with the SCR catalytic efficiency range threshold corresponding to each temperature interval until the time of each temperature interval exceeds the time threshold of each temperature interval and the proportion of the time of each temperature interval to the total time exceeds the time ratio threshold corresponding to each temperature interval.

For example, the temperature in the SCR can be divided into the following intervals: 0-180 ℃,180-230 ℃,230-270 ℃,270-320 ℃,320-400 ℃ and >400 ℃. Then calculating the SCR efficiency of each temperature interval, and respectively expressing the SCR efficiency by Eff1, eff2, eff3, eff4, eff5 and Eff 6; confirming that the time when the SCR is in each temperature interval is t1, t2, t3, t4, t5 and t6 respectively; the ratio of the time used in each temperature interval to the total time is calculated and is indicated by Dur1, dur 2, dur 3, dur 4, dur 5, dur6, respectively.

Comparing the time t 1-t 6 of each temperature interval with the time threshold value of each temperature interval, and comparing the proportion Dur 1-Dur 6 of the time used in each temperature interval in the total time with the time ratio threshold value corresponding to each temperature interval. And when the time t 1-t 6 of each temperature interval exceeds the time threshold of each temperature interval and the proportion Dur 1-Dur 6 of the time of each temperature interval to the total time exceeds the time ratio threshold corresponding to each temperature interval, comparing the SCR catalytic efficiency Eff 1-Eff 6 of each temperature interval with the SCR catalytic efficiency range threshold corresponding to each temperature interval.

3. Based on the second part, when the temperature rise in the SCR of the domestic and domestic aftertreatment system exceeds the temperature threshold, the SCR temperature change process is divided into a plurality of temperature sections, and the SCR catalytic efficiency of each temperature section is obtained. The rate of change of SCR catalytic efficiency is calculated for a preselected number of temperature intervals.

By integrating the three parts of content judgment, whether the SCR catalyst is seriously poisoned by sulfur can be determined: specifically, the judgment criterion may be that in the first section, the number of ammonia slip exceeds the threshold number of ammonia slip within a predetermined time range. In the second part, the SCR catalytic efficiency of each temperature interval in the SCR exceeds the SCR catalytic efficiency range threshold corresponding to each temperature interval. In a third portion, the rate of change of SCR catalytic efficiency for the preselected temperature interval is below a SCR catalytic efficiency rate of change threshold. When the three conditions are all satisfied, the SCR catalyst sulfur poisoning can be judged, and the SCR catalyst sulfur poisoning is determined to be in a second abnormal state.

Step 202: in response to the abnormal state, it is determined that warming measures are taken for the six aftertreatment system.

The temperature raising measures comprise the steps of continuously keeping the national six post-treatment system at the target temperature until the exhaust gas is treated by the national six post-treatment system, the discharge rate is not lower than the rate threshold, and the NOx content is not higher than the pollutant threshold.

In the embodiment of the application, two-stage heating measures are set, namely a first-stage heating measure and a second-stage heating measure.

Specifically, in response to the first abnormal state, it is determined that a first level warming measure is to be taken for the national six aftertreatment system. Wherein the first-level temperature rise measure indicates that the national six post-processing system is continuously kept at a first-level target temperature within a set time range. At a primary target temperature, in the six aftertreatment system, particulate matter is combusted into gas (CO) ₂ ) The urea is escaped, the urea crystals are dissolved, and the thermal decomposition of the sulfate promotes the SCR catalyst to recover the activity, thereby the SCR catalyst is obtained. The quality of the waste gas after passing through the six-country aftertreatment system can be effectively improved through a first-stage temperature rise measure, so that the overall performance of the six-country aftertreatment system is improved.

However, due to the influence of road conditions, diesel oil, an engine and other factors, the primary heating measures cannot completely promote the crystallization reaction of particles, sulfate and urea in the six post-treatment systems. Therefore, after the first-level temperature rising measure is finished, partial particulate matters, sulfate and urea crystals still exist in the six aftertreatment systems in China, and the treatment quality of the exhaust gas is influenced. After a period of time accumulation, the particle, sulfate and urea crystals in the six post-treatment systems are far beyond the first-stage temperature rise measure.

At this time, higher temperature is needed to promote the state of the six-country aftertreatment system to be restored to the initial state, namely, the particulate matter, the sulfate and the urea in the six-country aftertreatment system are fully reacted until the particulate matter, the sulfate and the urea are crystallized to be 0.

Accordingly, in response to the second abnormal state, it is determined that a secondary temperature-raising measure is taken for the sixth aftertreatment system. Wherein the secondary heating measures indicate that the national six after-treatment system is continuously maintained at the secondary target temperature until the exhaust gas passes through the national six after-treatment system, the emission rate is not lower than the first rate threshold, and the NOx content is not higher than the first pollutant threshold. The primary target temperature is lower than the secondary target temperature.

In the six post-treatment system of China, the temperature is continuously too high, so that the diesel oil consumption is large, and the system is aged. Therefore, two-stage heating measures including one-stage heating measure are arranged, and the effects of saving diesel oil and slowing down system aging can be achieved.

It is worth noting that the temperature raising measures have the periodic characteristic, namely different temperature raising measures are taken for the national six post-processing system according to the abnormal state, and after the temperature raising measures are finished, the temperature raising measures are taken again when the abnormal state occurs.

The method is described for determining that the exhaust gas is in an abnormal state after passing through the six aftertreatment systems based on main reference parameters (DPF carbon loading, SCR urea crystallization amount and SCR catalytic efficiency) and taking a temperature rise measure in response to the abnormal state.

As shown in FIG. 4, a flow chart is provided for determining a first order warming action to be taken with respect to a sixth aftertreatment system in response to a first abnormal condition. And when any abnormal value corresponding to the DPF carbon loading capacity, the SCR urea crystallization amount and the SCR catalytic efficiency exceeds a corresponding low-temperature threshold, or the product of the abnormal values corresponding to the DPF carbon loading capacity, the SCR urea crystallization amount and the SCR catalytic efficiency exceeds a corresponding low-temperature threshold, determining that the exhaust gas is in a first abnormal state after passing through the national six post-treatment system. Thus, in response to the first abnormal state, it is determined that a first level warming measure is to be taken for the sixth aftertreatment system. For example, after the abnormal value corresponding to the DPF carbon amount is determined, the abnormal value corresponding to the DPF carbon amount is inputted, and when the abnormal value corresponding to the DPF carbon amount exceeds the low temperature threshold, it is determined to be greater than (>), and the first abnormal state can be determined. It is thus determined that a first level warming action is to be taken for the six aftertreatment system in response to the first exception state.

As shown in FIG. 5, a flow chart is provided for the present application for determining a secondary warming action to be taken with respect to a sixth aftertreatment system in response to a second abnormal condition. And when any abnormal value corresponding to the DPF carbon loading capacity, the SCR urea crystallization amount and the SCR catalytic efficiency exceeds a corresponding high-temperature threshold, or the SCR catalyst is judged to be poisoned by sulfur, determining that the exhaust gas passes through the six post-treatment systems in China and is in a second abnormal state. Thus, in response to the second abnormal state, it is determined that a secondary warming measure is to be taken for the sixth aftertreatment system. For example, after the abnormal value corresponding to the SCR urea crystal amount is determined, the abnormal value corresponding to the SCR urea crystal amount is inputted, and the abnormal value is determined to be greater than the high temperature threshold value (i), and the second abnormal state can be determined. Thus, in response to the second abnormal state, it is determined that a secondary warming measure is to be taken for the sixth aftertreatment system.

Based on the same inventive concept, an exhaust gas treatment device provided in the embodiments of the present application is applied to a national six post-treatment system, the device corresponds to the aforementioned exhaust gas treatment method shown in fig. 2, and the specific implementation of the device can refer to the description of the aforementioned method embodiment, and repeated descriptions are omitted, referring to fig. 6, and the device includes:

the determination unit 601: the device is used for determining that the waste gas is in an abnormal state after passing through the national six post-treatment system; wherein the abnormal condition indicates that the exhaust gas has passed through the six aftertreatment systems at a rate below a rate threshold and/or a NOx level above a pollutant threshold.

Specifically, the abnormal state comprises a first abnormal state and a second abnormal state; wherein the first abnormal state indicates that the exhaust gas enters a first abnormal range after passing through the sixth aftertreatment system and the emission rate is lower than a first rate threshold, and/or the content of NOx is higher than a first pollutant threshold; the second abnormal state indicates that the exhaust gas enters a second abnormal range after passing through the national six post-treatment system and the discharge rate is lower than a second rate threshold value and/or the content of NOx is higher than a second pollutant threshold value; the second rate threshold is less than the first rate threshold, and the second contamination threshold is greater than the first contamination threshold.

The determination unit 601 is also used for determining the DPF carbon loading, the SCR urea crystallization amount, and the SCR catalytic efficiency in the six aftertreatment systems. Wherein the DPF carbon loading indicates an exhaust rate of exhaust gas treated by a national six after-treatment system; and the SCR urea crystallization amount and the SCR catalytic efficiency indicate the content of NOx in the exhaust gas after passing through the national six post-treatment system. And determining abnormal values corresponding to at least one parameter of DPF carbon loading, SCR urea crystallization amount and SCR catalytic efficiency. If the abnormal value exceeds the corresponding low-temperature threshold, determining that the exhaust gas is in the first abnormal state after passing through the national six post-treatment system; and if the abnormal value exceeds the corresponding high-temperature threshold value, determining that the exhaust gas is in the second abnormal state after passing through the national six post-treatment system.

The determining unit 601 is further configured to detect the number of times of ammonia leakage of the national six post-treatment system within a set time range; when the temperature rise in the SCR of the national six post-treatment system exceeds a temperature threshold, dividing the SCR temperature change process into a plurality of temperature intervals; calculating the SCR catalytic efficiency of the plurality of temperature intervals and the change rate of the SCR catalytic efficiency of the preselected temperature intervals; comparing the ammonia leakage frequency within the set time range with an ammonia leakage frequency threshold value; comparing the SCR catalytic efficiency of a plurality of temperature intervals in the SCR with the SCR catalytic efficiency range threshold corresponding to each temperature interval; comparing the rate of change of the SCR catalytic efficiency of the preselected temperature interval to an SCR catalytic efficiency rate of change threshold; and when the ammonia leakage frequency exceeds an ammonia leakage frequency threshold value within a set time range, the SCR catalytic efficiency of each temperature interval in the SCR is within the SCR catalytic efficiency range threshold value corresponding to each temperature interval, and the SCR catalytic efficiency change rate of the preselected temperature interval is lower than the SCR catalytic efficiency change rate threshold value, determining to respond to a second abnormal state.

Temperature increasing unit 602: the system comprises a control unit, a temperature raising unit, a temperature detecting unit and a temperature control unit, wherein the control unit is used for responding to an abnormal state and determining that temperature raising measures are taken for a national six post-processing system; wherein the temperature-raising measure comprises continuously maintaining the national six after-treatment system at the target temperature until the exhaust gas is treated by the national six after-treatment system, the emission rate is not lower than the rate threshold, and the NOx content is not higher than the pollutant threshold.

Specifically, in response to a first abnormal state, determining to take a first-level warming measure for a national sixth aftertreatment system; wherein the first-level temperature rise measure indicates that the national six post-processing system is continuously kept at a first-level target temperature within a set time range. In response to the second abnormal state, determining to take a secondary heating measure for the national sixth aftertreatment system; wherein the secondary heating measures indicate that the national six after-treatment system is continuously maintained at the secondary target temperature until the exhaust gas passes through the national six after-treatment system, the emission rate is not lower than the first rate threshold, and the NOx content is not higher than the first pollutant threshold; the primary target temperature is lower than the secondary target temperature.

Based on the same inventive concept, an embodiment of the present application further provides a readable storage medium, including:

a memory for storing a plurality of data to be transmitted,

the memory is configured to store instructions that, when executed by the processor, cause the apparatus including the readable storage medium to perform the method of exhaust gas treatment as described above.

It will be clear to those skilled in the art that, for convenience and simplicity of description, the foregoing division of the functional modules is merely used as an example, and in practical applications, the above function distribution may be performed by different functional modules according to needs, that is, the internal structure of the device is divided into different functional modules to perform all or part of the above described functions. For the specific working processes of the system, the apparatus and the unit described above, reference may be made to the corresponding processes in the foregoing method embodiments, and details are not described here again.

In the embodiments provided in the present invention, it should be understood that the disclosed apparatus and method may be implemented in other ways. For example, the above-described apparatus embodiments are merely illustrative, and for example, the division of the modules or units is only one logical division, and there may be other divisions when actually implemented, for example, a plurality of units or components may be combined or may be integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form.

The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.

In addition, functional units in the embodiments of the present application may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit.

The integrated unit, if implemented in the form of a software functional unit and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present application may be substantially implemented or contributed by the prior art, or all or part of the technical solution may be embodied in a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, a network device, or the like) or a processor (processor) to execute all or part of the steps of the method according to the embodiments of the present application. And the aforementioned storage medium includes: various media capable of storing program codes, such as a Universal Serial Bus flash disk (usb flash disk), a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk, or an optical disk.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.

Claims

1. A method for treating exhaust gas, which is applied to a national six post-treatment system, and is characterized by comprising the following steps:

determining the carbon loading capacity of the DPF, the crystallization amount of the SCR urea and the catalytic efficiency of the SCR in the post-treatment system; wherein the DPF carbon loading indicates an exhaust rate of exhaust gas after treatment by the national six after-treatment system; the SCR urea crystallization amount and the SCR catalytic efficiency indicate the content of NOx in the exhaust gas after passing through the national six post-treatment system;

determining abnormal values corresponding to at least one parameter of the DPF carbon loading capacity, the SCR urea crystallization capacity and the SCR catalytic efficiency according to respective preset look-up tables of the DPF carbon loading capacity, the SCR urea crystallization capacity and the SCR catalytic efficiency;

if any abnormal value exceeds a corresponding low-temperature threshold value, or the product of abnormal values corresponding to the carbon loading of the DPF, the urea crystallization amount of the SCR and the catalytic efficiency of the SCR exceeds a corresponding low-temperature threshold value, determining that the exhaust gas is in a first abnormal state after passing through the national six post-treatment system; wherein the first abnormal state indicates that the exhaust gas after passing through the national sixth aftertreatment system has an emission rate below a first rate threshold and/or a NOx content above a first pollutant threshold, entering a first abnormal range;

if any abnormal value exceeds the corresponding high-temperature threshold value, determining that the exhaust gas is in a second abnormal state after passing through the national post-treatment system; wherein the second abnormal state indicates that the exhaust gas enters a second abnormal range after passing through the sixth aftertreatment system, the emission rate is lower than a second rate threshold, and/or the content of NOx is higher than a second pollutant threshold; the second rate threshold is less than the first rate threshold, the second contamination threshold is greater than the first contamination threshold;

in response to the first abnormal state, determining to take a first-level warming measure for the national six aftertreatment system; wherein the first-level temperature rise measure indicates that the national six post-processing system is continuously kept at a first-level target temperature within a set time range;

in response to the second abnormal state, determining to take a secondary warming measure for the national six aftertreatment system; wherein the secondary heating measure indicates that the national six after-treatment system is continuously maintained at a secondary target temperature until the exhaust gas passes through the national six after-treatment system, the emission rate is not lower than the first rate threshold, and the NOx content is not higher than the first pollutant threshold; the primary target temperature is lower than the secondary target temperature.

2. The method of claim 1, wherein the determining that the exhaust gas is in the second abnormal state after passing through a national six aftertreatment system, further comprises:

when the temperature rise in the SCR of the national six post-treatment system exceeds a temperature threshold, dividing the SCR temperature change process into a plurality of temperature intervals;

comparing the ammonia leakage frequency within the set time range with an ammonia leakage frequency threshold value; comparing the SCR catalytic efficiency of a plurality of temperature intervals in the SCR with the SCR catalytic efficiency range threshold corresponding to each temperature interval; comparing the rate of change of SCR catalytic efficiency for the preselected temperature interval to an SCR catalytic efficiency rate of change threshold;

3. The method of claim 2, wherein comparing the SCR catalytic efficiency for a plurality of temperature intervals in the SCR to an SCR catalytic efficiency range threshold for each temperature interval comprises:

acquiring the time of the SCR in the temperature intervals respectively and the proportion of the time of the temperature intervals to the total time; wherein the total time refers to the sum of the time of each temperature interval in the SCR;

4. The utility model provides an exhaust-gas treatment's device, is applied to six post-treatment systems in state, its characterized in that includes:

a determination unit: the method is used for determining the carbon loading capacity of the DPF, the crystallization capacity of the SCR urea and the catalytic efficiency of the SCR in the post-treatment system; wherein the DPF carbon loading indicates an exhaust rate of exhaust gas after treatment by the national six after-treatment system; the SCR urea crystallization amount and the SCR catalytic efficiency indicate the content of NOx in the exhaust gas after passing through the national six post-treatment system; determining abnormal values corresponding to at least one parameter of the DPF carbon loading capacity, the SCR urea crystallization capacity and the SCR catalytic efficiency according to preset look-up tables of the DPF carbon loading capacity, the SCR urea crystallization capacity and the SCR catalytic efficiency; if any abnormal value exceeds a corresponding low-temperature threshold value, or the product of abnormal values corresponding to the carbon loading of the DPF, the urea crystallization amount of the SCR and the catalytic efficiency of the SCR exceeds a corresponding low-temperature threshold value, determining that the exhaust gas is in a first abnormal state after passing through the national six post-treatment system; wherein the first abnormal state indicates that the exhaust gas after passing through the national sixth aftertreatment system has an emission rate below a first rate threshold and/or a NOx content above a first pollutant threshold, entering a first abnormal range; if any abnormal value exceeds the corresponding high-temperature threshold value, determining that the exhaust gas is in a second abnormal state after passing through the national six post-treatment system; wherein the second abnormal state indicates that the exhaust gas enters a second abnormal range after passing through the sixth aftertreatment system, the emission rate is lower than a second rate threshold, and/or the content of NOx is higher than a second pollutant threshold; the second rate threshold is less than the first rate threshold, the second contamination threshold is greater than the first contamination threshold;

a temperature increasing unit: the first abnormal state is used for responding to and determining that first-level temperature rising measures are taken for the national six post-processing system; wherein the first-level temperature rise measure indicates that the national six post-processing system is continuously kept at a first-level target temperature within a set time range; in response to the second abnormal state, determining to take a secondary warming measure for the national six aftertreatment system; wherein the secondary heating measure indicates that the national six after-treatment system is continuously maintained at a secondary target temperature until the exhaust gas passes through the national six after-treatment system, the emission rate is not lower than the first rate threshold, and the NOx content is not higher than the first pollutant threshold; the primary target temperature is lower than the secondary target temperature.

5. The apparatus of claim 4, wherein the determination unit is further configured to detect a number of ammonia leaks in the six aftertreatment system within a set time frame; when the temperature rise in the SCR of the national six post-treatment system exceeds a temperature threshold, dividing the SCR temperature change process into a plurality of temperature intervals; calculating the SCR catalytic efficiency of the plurality of temperature intervals and the change rate of the SCR catalytic efficiency of the preselected temperature intervals; comparing the ammonia leakage frequency within the set time range with an ammonia leakage frequency threshold value; comparing the SCR catalytic efficiency of a plurality of temperature intervals in the SCR with the SCR catalytic efficiency range threshold corresponding to each temperature interval; comparing the rate of change of SCR catalytic efficiency for the preselected temperature interval to an SCR catalytic efficiency rate of change threshold; and when the ammonia leakage frequency exceeds an ammonia leakage frequency threshold value within a set time range, the SCR catalytic efficiency of each temperature interval in the SCR is within the SCR catalytic efficiency range threshold value corresponding to each temperature interval, and the SCR catalytic efficiency change rate of the preselected temperature interval is lower than the SCR catalytic efficiency change rate threshold value, determining that the exhaust gas is in the second abnormal state after passing through the national and international post-treatment systems.

6. A readable storage medium, comprising:

a memory for storing a plurality of data files to be transmitted,

the memory for storing instructions that, when executed by the processor, cause an apparatus comprising the readable storage medium to perform the method of any of claims 1~3.