Method for determining emission limit value of gaseous pollutants under simple working condition method

Abstract

The invention relates to the technical field of ignition type engine in-use automobile gaseous pollutant emission limit value design, in particular to a method for determining a gaseous pollutant emission limit value under a simple working condition method, and the method comprises the following steps: S1, classifying vehicles; s2, the gaseous pollutant emission concentration of the test vehicle under classification is obtained through a simple working condition method, and the frequency and the cumulative frequency of gaseous pollutant detection data are determined; s3, the relative emission concentration of gaseous pollutants is obtained; and S4, drawing a change curve of the relative concentration and the cumulative frequency of the gaseous pollutants, and determining the emission limit value of the gaseous pollutants. According to the method, the concept and method of the cumulative frequency in mathematical statistics are ingeniously used, a curve of the change of the cumulative frequency of the gaseous pollutant emission concentration along with the relative concentration is drawn, and a point of tangency of which the slope of the curve is 1 is a turning point of the change speed of the cumulative frequency of each pollutant detection value along with the respective relative concentration; and the problem that the pollutant emission limit value is too strict or too loose can be avoided.

Description

Technical Field

[0001] The invention relates to the technical field of design of emission limits of gaseous pollutants in-use automobiles with spark ignition engines, and in particular to a method for determining emission limits of gaseous pollutants under a simplified operating condition method. Background Art

[0002] At present, my country has not yet formed a fully mature method for determining the emission limits of gaseous pollutants under the simplified working condition method for in-use vehicles. The emission limits of gaseous pollutants under the simplified working condition method for in-use vehicles in the "Emission Limits and Measurement Methods of Pollutants for Gasoline Vehicles (Dual Idle Method and Simple Working Condition Method)" (GB18285-2018) are mostly based on the emission limit data of in-use vehicles of the United States EPA. Some data are determined based on the actual measured data of in-use vehicles and the control ratio of high-emission vehicles. Due to the different levels of economic development and technological reserves in various cities, most cities directly adopt the reference limits in the appendix of GB 18285-2018, and fail to formulate emission limits of gaseous pollutants under the simplified working condition method based on the actual measured data of in-use gasoline vehicles according to local actual conditions. At the same time, the setting of a 10% to 25% high-emission vehicle control ratio has certain limitations and subjectivity. The excess rate of vehicles with backward emission standards is usually higher than 25%, while the excess rate of vehicles with advanced emission standards is far lower than 10%. If the corresponding high-emission vehicle control ratio cannot be scientifically and reasonably divided for vehicles at different emission stages, the resulting emission limits of gaseous pollutants for in-use vehicles will be difficult to be accurate, scientific and rigorous, and will not be able to better reflect the actual emission level of current vehicles in use. Summary of the invention

[0003] In view of the problem that the existing method for determining the emission limits of gaseous pollutants under the simplified operating condition method determines the emission limits based on the control ratio of 10% to 25% high-emission vehicles, which has limitations and subjectivity and cannot well reflect the actual emission levels of currently in-use vehicles, the present invention provides a method for determining the emission limits of gaseous pollutants under the simplified operating condition method.

[0004] The technical solution of the present invention is as follows: A method for determining the emission limits of gaseous pollutants under a simplified operating condition method, which classifies vehicles, uses the simplified operating condition method to obtain the emission concentrations of gaseous pollutants of multiple test vehicles under the same classification, determines the frequency and cumulative frequency of occurrence of gaseous pollutant detection data, obtains the relative emission concentration of gaseous pollutants, draws a change curve of the relative concentration of gaseous pollutants and the cumulative frequency, and determines the emission limits of gaseous pollutants based on the curve.

[0005] Specifically, in a first aspect, the present invention provides a method for determining a carbon monoxide (CO) or hydrocarbon (HC) emission limit value based on a simplified operating condition method, the determination method comprising the following steps: S1. Classify vehicles, including at least eight categories according to the production period: pre-National I, National I, National II, National III, National IV, National V, National VIa and National VIb; S2. Use the simplified working condition method to obtain the gaseous pollutant emission concentrations of multiple test vehicles under the same classification, and statistically analyze the obtained gaseous pollutant detection data to determine the frequency and cumulative frequency of the gaseous pollutant detection data; S3. The gaseous pollutant emission concentration corresponding to the cumulative frequency greater than 99% is regarded as an abnormal value. The detected gaseous pollutant detection data is divided by the gaseous pollutant emission concentration corresponding to the cumulative frequency equal to 99% to obtain the relative emission concentration of gaseous pollutants; S4. Draw a variation curve with the relative concentration of gaseous pollutants as the horizontal axis and the cumulative frequency as the vertical axis. Take the value at the point where the tangent slope on the variation curve is 1, and use the gaseous pollutant detection data corresponding to the value as the emission limit.

[0006] In a second aspect, the present invention further provides a method for determining a nitrogen oxide (NO) emission limit value based on a simplified operating condition method, the determination method comprising the following steps: S1. Classify vehicles, including at least eight categories according to the production period: pre-National I, National I, National II, National III, National IV, National V, National VIa and National VIb; Classify regions, and list those with more than 5 million vehicles or where motor vehicle emissions are the primary source of air pollution as key regions, and those that do not meet the above conditions as general regions; S2. Use the simplified working condition method to obtain the gaseous pollutant emission concentrations of multiple test vehicles under the same classification, and statistically analyze the obtained gaseous pollutant detection data to determine the frequency and cumulative frequency of the gaseous pollutant detection data; S3. The gaseous pollutant emission concentration corresponding to the cumulative frequency greater than 99% is regarded as an abnormal value. The detected gaseous pollutant detection data is divided by the gaseous pollutant emission concentration corresponding to the cumulative frequency equal to 99% to obtain the relative emission concentration of gaseous pollutants; S4. Draw a change curve with the relative concentration of gaseous pollutants as the horizontal axis and the cumulative frequency as the vertical axis. Take the value at the point where the tangent slope is 1 on the change curve, and use the gaseous pollutant detection data corresponding to this value as the emission limit of National III, National IV, and National V vehicles in general areas. The emission limit of National III, National IV, and National V vehicles in key areas is 70% of the emission limit of National III, National IV, and National V vehicles in general areas; Find the gaseous pollutant detection data corresponding to the cumulative frequency of 0% on the change curve, and use it as the emission limit for pre-National I vehicles in key areas and general areas; Find the gaseous pollutant detection data corresponding to the cumulative frequencies of 40% and 60% on the change curve in sequence, and use them as the emission limits for National I vehicles in key areas and general areas respectively; Find the gaseous pollutant detection data corresponding to the cumulative frequencies of 60% and 80% on the change curve in sequence, and use them as the emission limits for National II vehicles in key areas and general areas respectively; Find the gaseous pollutant detection data corresponding to the cumulative frequencies of 98% and 100% on the change curve in sequence, and use them as the emission limits for National VI a vehicles in key areas and general areas respectively; Find the gaseous pollutant detection data corresponding to the cumulative frequency of 100% on the change curve, and use it as the emission limit for National VI b vehicles in key areas and general areas.

[0007] For the above two determination methods, further, S1 also includes: According to the vehicle reference mass (RM), the vehicles are divided into seven categories: RM ≤ 1020 kg, 1020 kg < RM ≤ 1250 kg, 1250 kg < RM ≤ 1470 kg, 1470 kg < RM ≤ 1700 kg, 1700 kg < RM ≤ 1930 kg, 1930 kg < RM ≤ 2150 kg, and 2150 kg < RM ≤ 2500 kg.

[0008] For the above two determination methods, further, the simple driving cycle method used in S2 is selected from the steady state driving cycle method or the simple transient driving cycle method, and each city selects the in-use light vehicle detection method according to its actual situation.

[0009] For the above two determination methods, further, the method for determining the frequency of occurrence of gaseous pollutant detection data in S2 is as follows: (1) Copy the gaseous pollutant detection data to column A of the Excel worksheet, start arranging from cell A1 and go down, and sort them in ascending order; (2) Write the function f(x) = countif(A:A, A1) in cell B1 of the same worksheet. Its physical meaning is the number of all gaseous pollutant detection concentrations in column A equal to the value in cell A1. Perform a fill operation on column B to calculate the number of identical values in the gaseous pollutant detection data; (3) Define the function f(x) = A1 = A2 in cell C1. If the gaseous pollutant detection concentration value in cell A1 is equal to the gaseous pollutant detection concentration value in cell A2, the proposition is true and cell C1 displays TRUE, otherwise it displays FALSE. Screen all FALSEs in column C, then it can ensure that the retained gaseous pollutant detection data values are all different, achieving the purpose of removing the same detection data values.

[0010] For the two determination methods mentioned above, further, the calculation formula of the cumulative frequency in S2 is: ; ; Where CFD is the cumulative frequency; n It is the numerical level number divided according to the minimum and maximum values ​​of the gaseous pollutant detection data. n Take a positive integer greater than or equal to 3; Indicated in i The frequency of occurrence of the variable within each numerical level; Refers to the frequency of the variable within the numerical level not greater than this value, that is, the frequency of the variable being less than a certain upper limit value; Indicated in n The total frequency of the variable within each numerical level.

[0011] The beneficial effects of the present invention are: The present invention ingeniously uses the most basic concept and method of cumulative frequency in mathematical statistics to draw the curve of the cumulative frequency of CO, HC and NO emission concentrations changing with their respective relative concentrations. The curve change rate (i.e., curve slope) is used as the key point, and it is proposed that the tangent point where the curve slope is 1 is the turning point of the change speed of the cumulative frequency of each pollutant detection value with their respective relative concentrations, which can avoid the problem of pollutant emission limits being too strict or too loose. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0013] Figure 1 This is the relative concentration and cumulative frequency change curve of CO emissions under the ASM5025 test condition in Example 2.

[0014] Figure 2 This is the curve of relative concentration and cumulative frequency of HC emissions under the ASM5025 test condition in Example 2.

[0015] Figure 3 This is the curve of relative concentration and cumulative frequency of NO emissions under the ASM5025 test condition in Example 2. DETAILED DESCRIPTION

[0016] To enable those skilled in the art to better understand the technical solutions in the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0017] Embodiment 1 A method for determining the emission limits of gaseous pollutants under the simple working condition method includes the following steps: S1. Classify vehicles: According to the regulations on vehicle national I, national II, national III, national IV, national V, national VIa, and national VIb emission stages in "Limits and Measurement Methods for Pollutant Emissions from Light-Duty Vehicles (China Phase I)" (GB18352.1-2001), "Limits and Measurement Methods for Pollutant Emissions from Light-Duty Vehicles (China Phase II)" (GB18352.2-2001), "Limits and Measurement Methods for Pollutant Emissions from Light-Duty Vehicles (China Phases III and IV)" (GB18352.3-2005), "Limits and Measurement Methods for Pollutant Emissions from Light-Duty Vehicles (China Phase V)" (GB18352.5-2013), and GB18352.6-2016, as well as the differences in engine and emission control technology levels of vehicles in different emission stages, combined with the vehicle classification results stipulated in GB 18285-2018, classify vehicles into eight categories: before national I, national I, national II, national III, national IV, national V, national VIa, and national VIb according to the vehicle production period; classify vehicles into seven categories: RM≤1020 kg, 1020 kg<RM≤1250kg, 1250 kg<RM≤1470 kg, 1470 kg<RM≤1700 kg, 1700 kg<RM≤1930 kg, 1930 kg<RM≤2150 kg, and 2150 kg<RM≤2500 kg according to the vehicle reference mass.

[0018] Classify regions: Based on the method of dividing regions for limit implementation in GB18285-2018, regions with an automobile ownership of more than 5 million or where motor vehicle emissions are the primary air pollution source in the local area are listed as key regions, and regions that do not meet the above conditions are listed as general regions.

[0019] S2. Use the simple working condition method (each city selects the steady state working condition method or the simple transient working condition method according to its actual situation) to obtain the gaseous pollutant emission concentrations of multiple test vehicles under the same classification. The gaseous pollutant emission concentrations include CO, HC, and / or NO, and statistically analyze the obtained gaseous pollutant detection data to determine the frequency and cumulative frequency of each gaseous pollutant detection data.

[0020] In the variable allocation series, the frequency indicates the degree of effect of the corresponding group mark value (or single object). The larger the frequency value, the greater the effect of the group mark value (or single object) on the overall level. Conversely, the smaller the frequency value, the smaller the effect of the group mark value (or single object) on the overall level. The cumulative frequency is the ratio of the number of occurrences of a variable less than a certain upper limit value to the total number of occurrences. Excel software can be used to count the frequency of occurrence of gaseous pollutant detection data, and the corresponding cumulative frequency can be calculated using the formula.

[0021] The frequency is determined as follows: (1) Copy the gaseous pollutant detection data to column A of the Excel worksheet, starting from cell A1 and sorting downward in ascending order.

[0022] (2) In cell B1 of the same worksheet, write the function f(x)=countif(A:A,A1). Its physical meaning is the number of gaseous pollutant detection concentrations in column A that are equal to the value in cell A1. Fill column B and calculate the number of identical values ​​in the gaseous pollutant detection data.

[0023] (3) Define the function f(x)=A1=A2 in cell C1. If the gaseous pollutant detection concentration value in cell A1 is equal to the gaseous pollutant detection concentration value in cell A2, the proposition is true and cell C1 displays TRUE. Otherwise, it displays FALSE. Filter all FALSE values ​​in column C to obtain the frequency of occurrence of gaseous pollutant detection data.

[0024] The cumulative frequency is calculated as: ; ; Where CFD is the cumulative frequency; n It is the numerical level number divided according to the minimum and maximum values ​​of the gaseous pollutant detection data. n Take a positive integer greater than or equal to 3; Indicated in i The frequency of occurrence of the variable within each numerical level; Refers to the frequency of the variable within the numerical level not greater than this value, that is, the frequency of the variable being less than a certain upper limit value; Indicated in n The total frequency of the variable within each numerical level.

[0025] S3. The gaseous pollutant emission concentration corresponding to the cumulative frequency greater than 99% is taken as the abnormal value. The detected gaseous pollutant detection data is divided by the gaseous pollutant emission concentration corresponding to the cumulative frequency equal to 99% to obtain the relative emission concentration of gaseous pollutants.

[0026] S4. Draw a change curve with the relative concentration of gaseous pollutants as the horizontal axis and the cumulative frequency as the vertical axis.

[0027] For CO and HC, the value is taken at the point where the tangent slope on the change curve is 1, and the gaseous pollutant detection data corresponding to this value is used as the emission limit. The cumulative frequency corresponding to the emission limit is the compliance rate.

[0028] For NO, the value is taken at the point where the tangent slope on the variation curve is 1, and the gaseous pollutant detection data corresponding to this value is used as the emission limit for National III, National IV and National V vehicles in general areas. The cumulative frequency corresponding to the emission limit is the compliance rate of National III, National IV and National V vehicles in general areas; the emission limit for National III, National IV and National V vehicles in key areas is 70% of the emission limit for National III, National IV and National V vehicles in general areas. The cumulative frequency corresponding to the emission limit is the compliance rate of National III, National IV and National V vehicles in key areas.

[0029] Light vehicles with spark-ignition engines in use before National I are generally carburetor vehicles, which are yellow-label vehicles that have been eliminated in my country; for National I and National II vehicles, due to their lower emission standards, they cause greater pollution hazards to the environment. Although there are fewer restrictions on the use of these vehicles in rural areas, in urban areas, in order to improve air quality, these old vehicles are strictly restricted from driving on the road. Taking Shandong Province as an example, yellow-label vehicles were banned from driving on the road in 2016; from 2024, National I and National II vehicles in Shandong Province have been banned from driving on the road in specific areas. Based on literature research and analysis of actual measured data of light vehicles in use using the simple operating condition method, the emission compliance rates of vehicles before National I in key areas and general areas are set to 0% and 0%, the emission compliance rates of National I vehicles in key areas and general areas are set to 40% and 60%, and the emission compliance rates of National II vehicles in key areas and general areas are set to 60% and 80%; Based on this, the gaseous pollutant detection data corresponding to the cumulative frequency of 0% is found on the change curve as the emission limit value for pre-National I vehicles in key areas and general areas. The cumulative frequency of 0% is the compliance rate of pre-National I vehicles in key areas and general areas. On the variation curve, find the gaseous pollutant detection data corresponding to the cumulative frequency of 40% and 60%, which are used as the emission limit values ​​of National I vehicles in key areas and general areas respectively. The cumulative frequencies of 40% and 60% are the compliance rates of National I vehicles in key areas and general areas; Find the gaseous pollutant detection data corresponding to the cumulative frequencies of 60% and 80% on the change curve in sequence, and use them as the emission limits of the National II vehicles in key areas and general areas respectively. The cumulative frequencies of 60% and 80% are the compliance rates of the National II vehicles in key areas and general areas respectively.

[0030] Set the emission compliance rates of the National VI a vehicles in key areas and general areas to 98% and 100% respectively, and the emission compliance rates of the National VI b vehicles in key areas and general areas to 100% and 100% respectively; Based on this, find the gaseous pollutant detection data corresponding to the cumulative frequencies of 98% and 100% on the change curve in sequence, and use them as the emission limits of the National VI a vehicles in key areas and general areas respectively. The cumulative frequencies of 98% and 100% are the compliance rates of the National VI a vehicles in key areas and general areas respectively; Find the gaseous pollutant detection data corresponding to the cumulative frequency of 100% on the change curve, and use it as the emission limit of the National VI b vehicles in key areas and general areas. The cumulative frequency of 100% is the compliance rate of the National VI b vehicles in key areas and general areas.

[0031] Example 2 Taking the determination of the gaseous pollutant emission limit of the National III vehicles under the steady-state condition method ASM5025 working condition with 1020 kg < RM ≤ 1250 kg classification as an example, this invention is further illustrated on the basis of Example 1.

[0032] Under the ASM5025 test working condition, the gaseous pollutant emission concentrations of a total of 23,770 National III test vehicles with 1020 kg < RM ≤ 1250 kg classification are obtained, including the CO emission concentration, HC emission concentration, and NO emission concentration. The obtained test concentrations of each gaseous pollutant are statistically analyzed to determine the frequency and cumulative frequency of the appearance of each gaseous pollutant test concentration. Taking the gaseous pollutant emission concentration value corresponding to the cumulative frequency greater than 99% as an outlier, divide the detected gaseous pollutant test concentration by the gaseous pollutant emission concentration corresponding to the cumulative frequency equal to 99% to obtain the relative emission concentration of the gaseous pollutant. Some results are shown in Tables 1 to 3 below.

[0033] Table 1 Frequency, relative emission concentration, and cumulative frequency of CO emission concentration under the ASM5025 test working condition

[0034] Table 2 Frequency, relative emission concentration, and cumulative frequency of HC emission concentration under the ASM5025 test working condition

[0035] Table 3 Frequency, relative emission concentration, and cumulative frequency of NO emission concentration under the ASM5025 test working condition

[0036] Separate change curves are plotted with the relative concentration of gaseous pollutants as the abscissa and the cumulative frequency as the ordinate, as Figures 1 to 3 shown. The red line in the figure represents the change curve, and the blue line represents the tangent line with a slope of 1.

[0037] On the change curves of the two gaseous pollutants CO and HC, points with a tangent slope of 1 are found respectively. The corresponding relative emission concentrations and cumulative frequencies of these points are (93%, 0.2%) and (94%, 48 ppm) respectively. Therefore, it can be concluded that for the national III vehicles in the classification of 1020 kg < RM ≤ 1250 kg, the CO emission compliance rate is 93%, the emission limit is 0.2%, the HC emission compliance rate is 94%, and the emission limit is 48 ppm.

[0038] On the change curve of NO, a point with a tangent slope of 1 is found. The corresponding relative emission concentration and cumulative frequency of this point are (90%, 388 ppm). Therefore, it can be concluded that for the national III vehicles in the classification of 1020 kg < RM ≤ 1250 kg in general areas, the NO emission compliance rate is 90%, and the emission limit is 388 ppm; for key areas, in accordance with the provisions of GB 18285-2018, the limit b can be selected in advance, and the limit b is 70% of the limit a, so the NO emission limit in key areas is 272 ppm.

[0039] Although the present invention has been described in detail by referring to the accompanying drawings and in combination with the preferred embodiments, the present invention is not limited thereto. Without departing from the spirit and essence of the present invention, those of ordinary skill in the art can make various equivalent modifications or substitutions to the embodiments of the present invention, and these modifications or substitutions should all be within the scope covered by the present invention / Any person familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed by the present invention, and they should all be covered by the protection scope of the present invention.

Claims

1. A method for determining the emission limit of gaseous pollutants under the simplified working condition method, characterized in that: The gaseous pollutants are carbon monoxide or hydrocarbons, and the determination method includes the following steps: S1. Classify the vehicles, including at least classifying the vehicles into eight categories: before National I, National I, National II, National III, National IV, National V, National VI a, and National VI b according to the production period; S2. Obtain the gaseous pollutant emission concentrations of multiple test vehicles under the same classification by using the simple working condition method, and statistically analyze the obtained gaseous pollutant detection data to determine the frequency and cumulative frequency of the gaseous pollutant detection data; S3. Take the gaseous pollutant emission concentration value corresponding to the cumulative frequency greater than 99% as the outlier, and divide the detected gaseous pollutant detection data by the gaseous pollutant emission concentration corresponding to the cumulative frequency equal to 99% to obtain the relative emission concentration of the gaseous pollutant; S4. Draw a change curve with the relative concentration of the gaseous pollutant as the abscissa and the cumulative frequency as the ordinate, take the value at the point where the tangent slope on the change curve is 1, and use the gaseous pollutant detection data corresponding to this value as the emission limit.

2. The method for determining the emission limit of gaseous pollutants under the simplified working condition method according to claim 1, characterized in that: S1 also includes classifying the vehicles into seven categories according to the vehicle reference mass: RM ≤ 1020 kg, 1020 kg < RM ≤ 1250 kg, 1250 kg < RM ≤ 1470 kg, 1470 kg < RM ≤ 1700 kg, 1700 kg < RM ≤ 1930 kg, 1930 kg < RM ≤ 2150 kg, and 2150 kg < RM ≤ 2500 kg.

3. The method for determining the emission limit of gaseous pollutants under the simplified working condition method according to claim 1, characterized in that: The simple working condition method used in S2 is selected from the steady state working condition method or the simple transient working condition method.

4. The method for determining the emission limit of gaseous pollutants under the simplified working condition method according to claim 1, characterized in that: The method for determining the frequency of the gaseous pollutant detection data in S2 is as follows: (1) Copy the gaseous pollutant detection data to column A of the Excel worksheet, arrange it downward starting from cell A1, and sort it in ascending order; (2) Write the function f(x)=countif(A:A,A1) in cell B1 of the same worksheet. Its physical meaning is the number of all gaseous pollutant detection concentrations in column A equal to the value in cell A1. Fill column B to calculate the number of the same values in the gaseous pollutant detection data; (3) Define the function f(x)=A1=A2 in cell C1. If the gaseous pollutant detection concentration value in cell A1 is equal to the gaseous pollutant detection concentration value in cell A2, the proposition is true, and cell C1 displays TRUE; otherwise, it displays FALSE. Filter all FALSE in column C to obtain the frequency of the gaseous pollutant detection data.

5. The method for determining the emission limit of gaseous pollutants under the simplified working condition method according to claim 1, characterized in that: The calculation formula for the cumulative frequency in S2 is expressed as: ； ； Where CFD is the cumulative frequency; n It is the numerical level number divided according to the minimum and maximum values ​​of the gaseous pollutant detection data. n Take a positive integer greater than or equal to 3; Indicated in i The frequency of occurrence of the variable within each numerical level; Refers to the frequency of the variable within the numerical level not greater than this value, that is, the frequency of the variable being less than a certain upper limit value; Indicated in n The total frequency of the variable within each numerical level.

6. A method for determining the emission limit of gaseous pollutants under the simplified working condition method, characterized in that: The gaseous pollutant is nitrogen monoxide, and the determination method includes the following steps: S1. Classify the vehicles, including at least classifying the vehicles into eight categories: before National I, National I, National II, National III, National IV, National V, National VI a, and National VI b according to the production period; Classify the regions. Regions with an automobile ownership of more than 5 million or where motor vehicle emissions are the primary air pollution source in the local area are listed as key regions, and regions that do not meet the above conditions are listed as general regions; S2. Obtain the gaseous pollutant emission concentrations of multiple test vehicles under the same classification using the simple driving cycle method, and statistically analyze the obtained gaseous pollutant detection data to determine the frequency and cumulative frequency of the gaseous pollutant detection data; S3. Take the gaseous pollutant emission concentration value corresponding to a cumulative frequency greater than 99% as an outlier, and divide the detected gaseous pollutant detection data by the gaseous pollutant emission concentration corresponding to a cumulative frequency equal to 99% to obtain the relative emission concentration of gaseous pollutants; S4. Draw a change curve with the relative concentration of gaseous pollutants as the abscissa and the cumulative frequency as the ordinate. Take the value at the point where the tangent slope on the change curve is 1, and use the gaseous pollutant detection data corresponding to this value as the emission limits for national III, national IV, and national V vehicles in general areas. The emission limits for national III, national IV, and national V vehicles in key areas are 70% of the emission limits for national III, national IV, and national V vehicles in general areas; Find the gaseous pollutant detection data corresponding to a cumulative frequency of 0% on the change curve as the emission limit for pre-national I vehicles in key areas and general areas; Find the gaseous pollutant detection data corresponding to cumulative frequencies of 40% and 60% on the change curve respectively as the emission limits for national I vehicles in key areas and general areas; Find the gaseous pollutant detection data corresponding to cumulative frequencies of 60% and 80% on the change curve respectively as the emission limits for national II vehicles in key areas and general areas; Find the gaseous pollutant detection data corresponding to cumulative frequencies of 98% and 100% on the change curve respectively as the emission limits for national VIa vehicles in key areas and general areas; Find the gaseous pollutant detection data corresponding to a cumulative frequency of 100% on the change curve as the emission limit for national VIb vehicles in key areas and general areas.

7. The method for determining the emission limit of gaseous pollutants under the simplified working condition method according to claim 6, characterized in that: S1 also includes classifying vehicles into seven categories according to the vehicle base mass: RM ≤ 1020 kg, 1020 kg < RM ≤ 1250 kg, 1250 kg < RM ≤ 1470 kg, 1470 kg < RM ≤ 1700 kg, 1700 kg < RM ≤ 1930 kg, 1930 kg < RM ≤ 2150 kg, and 2150 kg < RM ≤ 2500 kg.

8. The method for determining the emission limit of gaseous pollutants under the simplified working condition method according to claim 6, characterized in that: The simple driving cycle method used in S2 is selected from the steady state driving cycle method or the simple transient driving cycle method.

9. The method for determining the emission limit of gaseous pollutants under the simplified working condition method according to claim 6, characterized in that: The method for determining the frequency of the gaseous pollutant detection data in S2 is as follows: (1) Copy the gaseous pollutant detection data to column A of the Excel worksheet, arrange them in descending order starting from cell A1; (2) Write the function f(x)=countif(A:A,A1) in cell B1 of the same worksheet. Its physical meaning is the number of all gaseous pollutant detection concentrations in column A equal to the value in cell A1. Fill column B to calculate the number of identical values in the gaseous pollutant detection data; (3) Define the function f(x)=A1=A2 in cell C1. If the gaseous pollutant detection concentration value in cell A1 is equal to the gaseous pollutant detection concentration value in cell A2, the proposition is true and cell C1 displays TRUE. Otherwise, it displays FALSE. Filter all FALSE values ​​in column C to obtain the frequency of occurrence of gaseous pollutant detection data.

10. The method for determining the emission limit of gaseous pollutants under the simplified working condition method according to claim 6, characterized in that: The calculation formula of the cumulative frequency in S2 is expressed as: ； ； Where CFD is the cumulative frequency; n It is the numerical level number divided according to the minimum and maximum values ​​of the gaseous pollutant detection data. n Take a positive integer greater than or equal to 3; Indicated in i The frequency of occurrence of the variable within each numerical level; Refers to the frequency of the variable within the numerical level not greater than this value, that is, the frequency of the variable being less than a certain upper limit value; Indicated in n The total frequency of the variable within each numerical level.

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