An exhaust gas purification and after-treatment control method, controller, and after-treatment system.

Abstract

This application provides an exhaust gas purification aftertreatment control method, controller, and aftertreatment system, solving the technical problem in the prior art where sulfur, HC, etc., poison the upstream SCR during engine operation, leading to performance degradation and excessive NOx and N2O emissions. The exhaust gas purification aftertreatment control method provided in this application, in the regeneration control, uses the first temperature before the first NOx treatment device as the input temperature and the temperature at the outlet of the particulate filter as the target temperature when calculating the feedforward fuel quantity. Simultaneously, it uses the HC conversion efficiency of the first NOx treatment device and the particulate filter to correct the feedforward fuel quantity, improving the accuracy under transient fuel injection control, ensuring that the actual temperature of the particulate filter closely matches the target temperature, and guaranteeing sufficient detoxification by the first-stage NOx treatment device and complete oxidation of particulate matter in the particulate filter.

Description

Technical Field

[0001] This application relates to the field of automotive exhaust emission technology, specifically to an exhaust purification aftertreatment control method, controller, and aftertreatment system. Background Technology

[0002] Automobile exhaust is the waste gas produced when a car is in use. It contains hundreds of different compounds, including pollutants such as particulate matter, carbon monoxide, carbon dioxide, hydrocarbons, nitrogen oxides, lead, and sulfur oxides. Therefore, the exhaust gas produced by a car engine often needs to be treated before it is emitted.

[0003] In the process of exhaust gas treatment, an oxidation catalyst (DOC) is typically used to treat the exhaust gas, converting nitrogen monoxide and hydrocarbons in the exhaust gas into water and carbon dioxide. A selective catalytic reduction (SCR) device is then employed, injecting urea before the SCR to reduce nitrogen oxide emissions. A diesel particulate filter (DPF) is used to filter particulate matter from the exhaust gas, thereby reducing particulate matter emissions.

[0004] However, when the engine is running, sulfur, HC and other pollutants can poison the upstream SCR, leading to a decline in performance and causing NOx and N2O emissions to exceed the standards. Summary of the Invention

[0005] In view of this, this application provides an exhaust purification aftertreatment control method, controller and aftertreatment system, which solves the technical problem in the prior art that sulfur, HC and other substances will poison the front-stage SCR during engine operation, resulting in performance degradation and excessive NOx and N2O emissions.

[0006] To achieve the above objectives, this application provides an exhaust gas purification aftertreatment control method, which is applicable to an aftertreatment system. The aftertreatment system includes: a first nitrogen oxide treatment device, employing a reducing catalyst and an oxidizing catalyst, using injected urea to reduce nitrogen oxides and oxidize ammonia; a particulate capture device, employing an oxidizing catalyst to capture particles and nitrogen oxides; and a second nitrogen oxide treatment device, employing a reducing catalyst and an oxidizing catalyst, using injected urea to reduce nitrogen oxides and oxidize ammonia.

[0007] The control method includes:

[0008] Based on the first temperature before the first nitrogen oxide treatment device, the first nitrogen oxide concentration, the second temperature before the particle capture device, and the third temperature after the first nitrogen oxide treatment device, calculate the first urea injection rate before the first nitrogen oxide treatment device and the second urea injection rate before the second nitrogen oxide treatment device.

[0009] The injection of urea from the first nitrogen oxide treatment device is controlled according to the first urea injection volume, and the injection of urea from the second nitrogen oxide treatment device is controlled according to the second urea injection volume.

[0010] Based on the total amount of carbon and hydrogen, the total amount of sulfur, the actual conversion rate of nitrogen oxides in the pre-stage and the actual conversion rate of nitrogen oxides in the post-stage of the first nitrogen oxide treatment device, it is determined whether the first nitrogen oxide treatment device triggers the regeneration function.

[0011] When it is determined that the first nitrogen oxide treatment device triggers the regeneration function, the feed oil quantity of the first nitrogen oxide treatment device is calculated based on the first temperature before the first nitrogen oxide treatment device, the target temperature, the exhaust gas mass flow rate and the exhaust gas specific heat capacity.

[0012] The feedforward fuel quantity is injected into the first nitrogen oxide treatment device, and the first nitrogen oxide treatment device is controlled to enter the regeneration mode.

[0013] In one embodiment of this application, calculating the first urea injection rate before the first nitrogen oxide treatment device and the second urea injection rate before the second nitrogen oxide treatment device based on the first temperature before the first nitrogen oxide treatment device, the first nitrogen oxide concentration, the second temperature before the particulate capture device, and the third temperature thereafter includes:

[0014] The first urea injection rate before the first nitrogen oxide treatment device is calculated based on the first temperature and the first nitrogen oxide concentration before the first nitrogen oxide treatment device.

[0015] Based on the second temperature before the particle capture device and the third temperature after it, calculate the first concentration ratio of nitrogen dioxide concentration to total nitrogen oxide concentration before the second nitrogen oxide treatment device.

[0016] The second urea injection rate before the second nitrogen oxide treatment device is calculated based on the first concentration ratio of nitrogen dioxide concentration to total nitrogen oxide concentration before the second nitrogen oxide treatment device and the third temperature before the second nitrogen oxide treatment device.

[0017] In one embodiment of this application, calculating the first urea injection rate before the first nitrogen oxide treatment device based on the first temperature and the first nitrogen oxide concentration before the first nitrogen oxide treatment device includes:

[0018] The feedforward nitrogen oxide conversion efficiency is queried from a first preset data table based on the first temperature before the first nitrogen oxide treatment device and the air velocity in the first nitrogen oxide treatment device; wherein, the first preset data table stores a preset temperature, a preset air velocity, and a preset nitrogen oxide conversion efficiency corresponding to the preset temperature and the preset air velocity.

[0019] Calculate the feedforward nitrogen oxide mass flow rate of the first nitrogen oxide treatment device based on the first nitrogen oxide concentration and the exhaust gas mass flow rate before the first nitrogen oxide treatment device.

[0020] Calculate the mass flow rate of hydrogen nitride based on the feedforward mass flow rate of nitrogen oxides from the first nitrogen oxide treatment device;

[0021] The first urea injection rate before the first nitrogen oxide treatment device is calculated based on the mass flow rate of the hydrogen nitride.

[0022] In one embodiment of this application, calculating the first urea injection rate before the first nitrogen oxide treatment device based on the mass flow rate of the hydrogen nitride includes:

[0023] Calculate the initial urea injection rate before the first nitrogen oxide treatment device based on the mass flow rate of the hydrogen nitride.

[0024] The first temperature difference is calculated based on the first temperature before the first nitrogen oxide treatment device and the second temperature after it.

[0025] The correction coefficient corresponding to the first temperature difference is queried in the second preset data table according to the first temperature difference value. The second preset data table stores the preset temperature difference value and the preset correction coefficient corresponding to the preset temperature difference value.

[0026] The first initial urea injection amount is adjusted according to the correction coefficient to obtain the first urea injection amount.

[0027] In one embodiment of this application, the step of calculating the first concentration ratio of nitrogen dioxide concentration to total nitrogen oxide concentration before the second nitrogen oxide treatment device based on the second temperature before the particle capture device and the third temperature after the particle capture device includes:

[0028] The weighted temperature value is calculated based on the second temperature before the particle capture device and the third temperature after it.

[0029] Based on the weighted temperature value and the second air velocity of the particle capture device, the initial concentration ratio of nitrogen dioxide concentration to total nitrogen oxide concentration before the second nitrogen oxide treatment device corresponding to the weighted temperature value and the second air velocity is queried in the third preset data table. The third preset data table stores preset temperature value, preset air velocity and the corresponding preset concentration ratio of nitrogen dioxide concentration to total nitrogen oxide concentration.

[0030] The initial concentration ratio is corrected based on the nitrogen oxide concentration before the particle capture device to obtain a first concentration ratio of nitrogen dioxide concentration to total nitrogen oxide concentration before the second nitrogen oxide treatment device.

[0031] In one embodiment of this application, calculating the second urea injection rate before the second nitrogen oxide treatment device based on a first concentration ratio of nitrogen dioxide concentration to total nitrogen oxide concentration before the second nitrogen oxide treatment device and a third temperature before the second nitrogen oxide treatment device includes:

[0032] The third temperature before the second nitrogen oxide treatment device and the third space velocity of the second nitrogen oxide treatment device are used to look up the corresponding nitrogen oxide conversion efficiency in the fourth preset data table; wherein, the fourth preset data table stores preset temperature, preset space velocity, and preset nitrogen oxide conversion efficiency corresponding to the preset temperature and preset space velocity.

[0033] The nitrogen oxide conversion efficiency of the second nitrogen oxide treatment device is corrected based on a first concentration ratio of nitrogen dioxide concentration to total nitrogen oxide concentration before the second nitrogen oxide treatment device.

[0034] The second urea injection rate before the second nitrogen oxide treatment device is calculated based on the nitrogen oxide conversion efficiency of the modified second nitrogen oxide treatment device, the exhaust gas quality, and the nitrogen dioxide concentration before the second nitrogen oxide treatment device.

[0035] In one embodiment of this application, determining whether the first nitrogen oxide treatment device triggers the regeneration function based on the total hydrocarbon content, total sulfur content, actual conversion rate of nitrogen oxides in the preceding stage, and actual conversion rate of nitrogen oxides in the subsequent stage of the first nitrogen oxide treatment device includes:

[0036] A preset hydrocarbon conversion rate at the average temperature is determined based on the average temperature in the first nitrogen oxide treatment device; the total hydrocarbon amount of the first nitrogen oxide treatment device is calculated based on the amount of hydrocarbons emitted by the engine, the preset hydrocarbon conversion rate, and the amount of hydrocarbons that escaped stored in the first nitrogen oxide treatment device.

[0037] The amount of sulfur stored is calculated based on the average temperature in the first nitrogen oxide treatment unit, and the total amount of sulfur is calculated based on the amount of sulfur stored.

[0038] When the total amount of hydrocarbons in the first nitrogen oxide treatment device is greater than a preset total amount, or the total amount of sulfur in the first nitrogen oxide treatment device is greater than a preset poisoning amount, or the actual conversion rate of the preceding nitrogen oxides is less than a first preset conversion rate, or the actual conversion rate of the following nitrogen oxides is greater than a second preset conversion rate, the regeneration function is triggered.

[0039] In one embodiment of this application, after calculating the feedforward oil quantity of the first nitrogen oxide treatment device based on the first temperature before the first nitrogen oxide treatment device, the target temperature, the exhaust gas mass flow rate, and the exhaust gas specific heat capacity, the control method further includes:

[0040] A first correction value is determined based on the target temperature and the exhaust gas mass flow rate;

[0041] The feedforward oil quantity is adjusted according to the first correction value.

[0042] In one embodiment of this application, after calculating the feedforward oil quantity of the first nitrogen oxide treatment device based on the first temperature before the first nitrogen oxide treatment device, the target temperature, the exhaust gas mass flow rate, and the exhaust gas specific heat capacity, the control method further includes:

[0043] The total hydrocarbon conversion rate is calculated based on the hydrocarbon conversion rate of the first nitrogen oxide treatment device and the hydrocarbon conversion rate of the particulate capture device.

[0044] The feedforward oil quantity is corrected based on the total hydrocarbon conversion rate to obtain the corrected feedforward oil quantity.

[0045] As a second aspect of this application, this application also provides an exhaust gas purification aftertreatment controller, including...

[0046] The first calculation module is used to calculate the first urea injection rate before the first nitrogen oxide treatment device and the second urea injection rate before the second nitrogen oxide treatment device based on the first temperature before the first nitrogen oxide treatment device, the first nitrogen oxide concentration, the second temperature before the particle capture device and the third temperature after it.

[0047] The first control module is used to control the first nitrogen oxide treatment device to spray urea according to the first urea injection volume, and to control the second nitrogen oxide treatment device to spray urea according to the second urea injection volume.

[0048] The regeneration control module is used to determine whether the first nitrogen oxide treatment device should trigger the regeneration function based on the total hydrocarbon content, total sulfur content, actual nitrogen oxide conversion rate of the pre-stage and the actual nitrogen oxide conversion rate of the post-stage nitrogen oxide treatment device; when it is determined that the first nitrogen oxide treatment device has triggered the regeneration function, the module calculates the feed oil quantity of the first nitrogen oxide treatment device based on the first temperature before the first nitrogen oxide treatment device, the target temperature, the exhaust gas mass flow rate, and the exhaust gas specific heat capacity; injects the feed oil quantity of fuel into the first nitrogen oxide treatment device; and controls the first nitrogen oxide treatment device to enter the regeneration mode.

[0049] As a third aspect of this application, this application also provides an exhaust gas purification and after-treatment system, comprising:

[0050] The first nitrogen oxide treatment unit uses a reducing catalyst and an oxidizing catalyst to reduce nitrogen oxides and oxidize ammonia by spraying urea.

[0051] The particle capture device uses an oxidizing catalyst to capture particles and nitrides;

[0052] The second nitrogen oxide treatment unit uses a reducing catalyst and an oxidizing catalyst to reduce nitrogen oxides and oxidize ammonia by spraying urea.

[0053] Temperature sensors are used to detect the temperature of exhaust gas at different stages;

[0054] Nitrogen oxide sensors are used to detect the concentration of nitrogen oxides in exhaust gas at different stages; and

[0055] The post-processing controller described above.

[0056] The exhaust gas purification and aftertreatment control method provided in this application, after determining that the regeneration function of the first nitrogen oxide treatment device has been triggered, calculates the feedforward fuel quantity of the first nitrogen oxide treatment device based on the first temperature before the first nitrogen oxide treatment device, the target temperature, the exhaust gas mass flow rate, and the specific heat capacity of the exhaust gas. Then, fuel is injected into the first nitrogen oxide treatment device at the feedforward fuel quantity, and then burned in the first nitrogen oxide treatment device to raise the temperature in the first nitrogen oxide treatment device to the target temperature. When calculating the feedforward fuel quantity, the first temperature before the first nitrogen oxide treatment device is used as the input temperature, and the temperature at the outlet of the particulate matter capture device is used as the target temperature. This improves the accuracy of transient fuel injection control, making the actual temperature of the particulate matter capture device closely match the target temperature, ensuring sufficient detoxification by the first-stage nitrogen oxide treatment device and sufficient oxidation of particulate matter in the particulate matter capture device, thereby reducing NOx and N2O emissions. Attached Figure Description

[0057] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0058] Figure 1 This is a schematic diagram of an exhaust gas purification and after-treatment system provided in an embodiment of this application.

[0059] Figure 2 The diagram shown is a schematic flowchart of an exhaust gas purification and post-treatment control method provided in an embodiment of this application.

[0060] Figure 3 The diagram shown is a flowchart illustrating an exhaust gas purification and post-treatment control method according to another embodiment of this application.

[0061] Figure 4 The diagram shown is a flowchart illustrating an exhaust gas purification and post-treatment control method according to another embodiment of this application.

[0062] Figure 5 The diagram shown is a structural schematic of an exhaust gas purification and aftertreatment controller provided in another embodiment of this application. Detailed Implementation

[0063] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0064] For ease of description, the following explains some of the nouns or terms used in the embodiments of this application:

[0065] DPF (diesel particulate filter) is used to capture particulate matter in exhaust gases. When the captured particulate matter reaches a certain level, passive or active regeneration is required to restore the DPF's ability to capture particulate matter. The working principle of a DPF is as follows: NO2 has a strong oxidizing ability against captured particles. The generated NO2 is used as an oxidant to remove particles from the particulate filter and generate CO2. The NO2 is then reduced back to NO, thus achieving the purpose of removing particulate matter.

[0066] DPF internal reaction principle:

[0067]

[0068] DOC: Diesel Oxide Catalyst, used to convert HC, CO, etc. in waste gas, and to oxidize NO in tail gas to NO2. The working principle of DOC is as follows: Under temperature conditions of 200-600℃, CO and HC are almost completely oxidized to CO2 and H2O, respectively, while NO is converted to NO2. The reaction principle within DOC is as follows:

[0069]

[0070] DDPF: An integrated oxidation trap that is coated with both DOC and DPF formulations of catalyst in separate sections, combining the functions of both DPF and DOC.

[0071] SCR: Selective Catalytic Reduction. Urea is injected before the SCR unit to reduce nitrogen oxides in exhaust emissions. The working principle of SCR is as follows: fuel or a reducing agent is injected into the exhaust gas, and a suitable catalyst is used to promote the reaction between the reducing agent and NOx, while inhibiting the non-selective oxidation reaction between the reducing agent and oxygen. Commonly used urea-SCR catalysts include V2O5 / W2O3 / TiO2 and metal oxide / zeolite. Vanadium-based catalysts have high selectivity for NOx and a wide efficient temperature window, as well as high sulfur resistance. However, they are susceptible to poisoning by phosphorus components in the lubricating oil and high-temperature failure. Zeolite catalysts have a strong adsorption capacity for NH3, but at low temperatures, zeolite also has a strong adsorption capacity for HC. HC adsorption affects the low-temperature performance of the catalyst. Furthermore, zeolite has poor hydrothermal stability and sulfur resistance, thus limiting its practical application and requiring the use of low-sulfur fuels.

[0072] Sulfur oxides form sulfates in copper-based SCRs, reducing catalyst active sites, clogging pores, and decreasing the SCR's NOx conversion efficiency. Therefore, once a certain amount of sulfur oxides are captured within the SCR, desulfurization is necessary. Sulfur poisoning has two mechanisms: the formation of (NH4)SO4, etc., reducing SCR catalyst active sites and clogging pores, thereby decreasing NOx conversion efficiency; and SO2 and SO3 competing with NOx for adsorption, reducing NOx adsorption.

[0073] The reaction principle of SCR: Urea hydrolyzes into ammonia: (NH2)2CO + H2O → 2NH3 + CO2

[0074] pSCR: Passive Selective Catalytic Reduction, used to treat nitrogen oxides (NOx).

[0075] ASC: Ammonia Slip Catalyst, used to oxidize excess ammonia.

[0076] As a first aspect of this application, this application provides an exhaust gas purification and aftertreatment system. Figure 1 The diagram shown is a structural schematic of an exhaust gas purification and aftertreatment system according to an embodiment of this application. Figure 1 As shown, the exhaust gas purification and after-treatment system provided in this application includes:

[0077] The first nitrogen oxide treatment device A1 employs a reducing catalyst and an oxidizing catalyst, and uses urea injected through a urea nozzle to reduce nitrogen oxides and oxidize ammonia. The first nitrogen oxide treatment device A1 may include a selective catalytic conversion device SCR and an ammonia escape trap ASC, employing a reducing catalyst and an oxidizing catalyst, and using urea injected through an Inj1 urea nozzle to reduce NOx and oxidize excess NH3.

[0078] The particulate trapping device A2 uses an oxidizing catalyst to trap particles and nitrides; the particulate trapping device A2 may include a combination of DOC and DPF; or DDPF or cDPF.

[0079] The second nitrogen oxide treatment device A3 employs a reducing catalyst and an oxidizing catalyst, using injected urea to reduce nitrogen oxides and oxidize ammonia; the second nitrogen oxide treatment device A3 may include an SCR and an ASC.

[0080] Temperature sensors are used to detect the temperature of exhaust gas at different stages, such as... Figure 1 As shown, a first temperature sensor T1 installed at the inlet of the first nitrogen oxide treatment device A1 can detect the first temperature at the inlet of the first nitrogen oxide treatment device A1; a second temperature sensor T2 installed between the first nitrogen oxide treatment device A1 and the particulate capture device A2 can detect the second temperature at the outlet of the first nitrogen oxide treatment device A1; and a third temperature sensor installed at the outlet of the particulate capture device A2 can detect the third temperature of the exhaust gas at the outlet of the particulate capture device A2.

[0081] Nitrogen oxide sensors are used to detect the concentration of nitrogen oxides in exhaust gas at different stages; such as Figure 1As shown, a first nitrogen oxide sensor N1 installed at the inlet of the first nitrogen oxide treatment device A1 can detect the first nitrogen oxide concentration at the inlet of the first nitrogen oxide treatment device A1; a second nitrogen oxide sensor N2 installed between the first nitrogen oxide treatment device A1 and the particulate capture device A2 can detect the second nitrogen oxide concentration at the outlet of the first nitrogen oxide treatment device A1; and a third nitrogen oxide sensor N3 installed at the outlet of the second nitrogen oxide treatment device A3 can detect the third nitrogen oxide concentration at the outlet of the second nitrogen oxide treatment device A3.

[0082] The post-treatment system provided in this application uses a first-stage nitrogen oxide treatment device that has the functions of reducing NOx and oxidizing HC. Depending on the poisoning situation, regeneration control is triggered to restore the first-stage nitrogen oxide treatment device to a certain temperature.

[0083] As a second aspect of this application, this application also provides a method for controlling exhaust gas purification and aftertreatment, for controlling Figure 1 The exhaust gas purification and after-treatment system shown is Figure 2 The diagram shown is a schematic flow chart of an exhaust gas purification and aftertreatment control method according to an embodiment of this application. Figure 2 As shown, an exhaust gas purification and post-treatment control method includes the following steps:

[0084] S1: Calculate the first urea injection rate before the first nitrogen oxide treatment device and the second urea injection rate before the second nitrogen oxide treatment device based on the first temperature before the first nitrogen oxide treatment device, the first nitrogen oxide concentration, the second temperature before the particle capture device, and the third temperature after the particle capture device.

[0085] The first temperature is detected by the first temperature sensor T1 located at the inlet of the first nitrogen oxide treatment device A1. The first nitrogen oxide concentration is detected by the first nitrogen oxide sensor N1 located at the inlet of the first nitrogen oxide treatment device A1. The second temperature is detected by the second temperature sensor T2 located at the outlet of the first nitrogen oxide treatment device A1 (i.e., the inlet of the particulate capture device A2). The third temperature is detected by the third temperature sensor T3 located at the outlet of the particulate capture device A2.

[0086] S2: Control the injection of urea from the first nitrogen oxide treatment device according to the first urea injection volume, and control the injection of urea from the second nitrogen oxide treatment device according to the second urea injection volume;

[0087] Once the first urea injection quantity is determined, the urea nozzle can be controlled to inject urea into the first nitrogen oxide treatment device A1 according to the first urea injection quantity. Similarly, once the second urea injection quantity is determined, the urea nozzle can be controlled to inject urea into the second nitrogen oxide treatment device A3 according to the second urea injection quantity.

[0088] S3: Determine whether the first nitrogen oxide treatment device A1 should trigger the regeneration function based on the total amount of carbon and hydrogen, the total amount of sulfur, the actual conversion rate of nitrogen oxides in the front stage and the actual conversion rate of nitrogen oxides in the back stage.

[0089] Specifically, the first nitrogen oxide treatment unit can be determined to trigger the regeneration function if any one of the following four conditions is met:

[0090] (1) The total amount of hydrocarbons in the first nitrogen oxide treatment device A1 is greater than the preset total amount;

[0091] (2) The total sulfur content in the first nitrogen oxide treatment device A1 is greater than the preset poisoning level;

[0092] (3) The actual conversion rate of nitrogen oxides in the pre-stage of the first nitrogen oxide treatment device A1 is less than the first preset conversion rate;

[0093] (4) The actual conversion rate of nitrogen oxides in the downstream stage of the first nitrogen oxide treatment device A1 is greater than the second preset conversion rate.

[0094] S4: When it is determined that the first nitrogen oxide treatment device triggers the regeneration function, the feed oil quantity of the first nitrogen oxide treatment device is calculated based on the first temperature before the first nitrogen oxide treatment device, the target temperature, the exhaust gas mass flow rate and the exhaust gas specific heat capacity.

[0095] If it is determined in S3 that the first nitrogen oxide treatment device A1 triggers the regeneration function, the feed-forward oil quantity of the first nitrogen oxide treatment device is calculated based on the first temperature before the first nitrogen oxide treatment device, the target temperature, the exhaust gas mass flow rate, and the exhaust gas specific heat capacity.

[0096] The target temperature refers to the target temperature in the first nitrogen oxide treatment device A1, for example, the target temperature can be 450°C.

[0097] Specifically, the formula for calculating the feedforward fuel quantity is: Feedforward fuel quantity = specific heat capacity of exhaust gas * mass flow rate of exhaust gas * (target temperature - first temperature) / calorific value of fuel.

[0098] S5: Inject feedforward fuel into the first nitrogen oxide treatment unit and control the first nitrogen oxide treatment unit to enter the regeneration mode.

[0099] When the first NOx treatment device A1 triggers the regeneration function, after calculating the feedforward oil quantity of the first NOx treatment device, the first NOx treatment device A1 enters the thermal management mode, injects fuel into the first NOx treatment device A1 with the feedforward oil quantity, and then burns it in the first NOx treatment device A1 to raise the temperature in the first NOx treatment device A1 to the target temperature (e.g., the target temperature is 450°C) or higher.

[0100] The exhaust gas purification and aftertreatment control method provided in this application, after determining that the regeneration function of the first nitrogen oxide treatment device A1 has been triggered, calculates the feedforward fuel quantity of the first nitrogen oxide treatment device based on the first temperature before the first nitrogen oxide treatment device, the target temperature, the exhaust gas mass flow rate, and the exhaust gas specific heat capacity. Then, fuel is injected into the first nitrogen oxide treatment device A1 using the feedforward fuel quantity, and then combusted in the first nitrogen oxide treatment device A1 to raise the temperature in the first nitrogen oxide treatment device A1 to the target temperature. In calculating the feedforward fuel quantity, the first temperature before the first nitrogen oxide treatment device is used as the input temperature, and the temperature at the outlet of the particulate filter is used as the target temperature. This improves the accuracy of transient fuel injection control, ensuring that the actual temperature of the particulate filter closely matches the target temperature, guaranteeing sufficient detoxification by the first-stage nitrogen oxide treatment device and sufficient oxidation of particulate matter in the particulate filter, thereby reducing NOx and N2O emissions.

[0101] In addition, when calculating the feedforward oil quantity, the first temperature and target temperature before the first nitrogen oxide treatment device are used. Since the first temperature is stable, the calculated feedforward oil quantity will not deviate significantly, thus making the exhaust gas temperature in the first nitrogen oxide treatment device A1 uniform. When the exhaust gas enters the particulate capture device A2, the particulate matter can be fully oxidized and burned, improving the ability of the regenerated DPF to capture particulate matter, thereby improving the regeneration efficiency.

[0102] In one embodiment of this application, as Figure 3 As shown, the specific calculation method for calculating the first urea injection rate before the first nitrogen oxide treatment device A1 and the second urea injection rate before the second nitrogen oxide treatment device A3, namely S1 (calculating the first urea injection rate before the first nitrogen oxide treatment device and the second urea injection rate before the second nitrogen oxide treatment device based on the first temperature before the first nitrogen oxide treatment device, the first nitrogen oxide concentration, the second temperature before the particulate capture device, and the third temperature afterward), specifically includes the following steps:

[0103] S11: Calculate the first urea injection rate before the first nitrogen oxide treatment device based on the first temperature and the first nitrogen oxide concentration before the first nitrogen oxide treatment device;

[0104] Specifically, S11 includes the following steps:

[0105] S110: Based on the first temperature before the first nitrogen oxide processing device A1 and the air velocity in the first nitrogen oxide processing device A1, query the corresponding feedforward nitrogen oxide conversion efficiency in the first preset data table; wherein, the first preset data table stores the preset temperature, the preset air velocity, and the preset nitrogen oxide conversion efficiency corresponding to the preset temperature and the preset air velocity.

[0106] Specifically, the air velocity can be calculated by dividing the exhaust gas mass flow rate by the product of the exhaust gas density and the volume of the first nitrogen oxide treatment device A1.

[0107] Specifically, the first preset data table is pre-built. Once the first temperature and space velocity are determined, the corresponding feedforward nitrogen oxide conversion efficiency can be obtained by querying the first preset data table.

[0108] S111: Calculate the feedforward nitrogen oxide mass flow rate of the first nitrogen oxide treatment device based on the first nitrogen oxide concentration and the exhaust gas mass before the first nitrogen oxide treatment device;

[0109] S112: Calculate the mass flow rate of hydrogen nitride based on the feedforward nitrogen oxide mass flow rate and the feedforward nitrogen oxide conversion efficiency of the first nitrogen oxide treatment device;

[0110] The reaction ratio of nitrogen oxides to hydrogen nitride is set to 1:1, and then the mass flow rate of hydrogen nitride is calculated based on the feedforward mass flow rate of nitrogen oxides.

[0111] S113: Calculate the first urea injection rate before the first nitrogen oxide treatment unit based on the mass flow rate of hydrogen nitride.

[0112] Once the mass flow rate of hydrogen nitride is calculated, the first urea injection quantity can be calculated based on the mass flow rate of hydrogen nitride.

[0113] Specifically, S113 (calculating the first urea injection rate before the first nitrogen oxide treatment unit based on the mass flow rate of hydrogen nitride) includes the following steps:

[0114] S1131: Calculate the initial urea injection rate before the first nitrogen oxide treatment unit based on the mass flow rate of hydrogen nitride;

[0115] First, the initial urea injection rate before the first nitrogen oxide treatment unit is calculated based on the mass flow rate of hydrogen nitride.

[0116] S1132: Calculate the first temperature difference based on the first temperature before the first nitrogen oxide treatment device and the second temperature after it;

[0117] When the first nitrogen oxide treatment unit A1 oxidizes HC, it will inhibit the SCR reaction. When the temperature in the first nitrogen oxide treatment unit A1 exceeds 400℃, the oxidation will have a significant impact on the NOx reaction. Therefore, it is necessary to correct the urea injection amount based on the temperature difference before and after the first nitrogen oxide treatment unit A1.

[0118] S1133: Query the correction coefficient corresponding to the first temperature difference in the second preset data table according to the first temperature difference, wherein the second preset data table stores the preset temperature difference and the preset correction coefficient corresponding to the preset temperature difference.

[0119] Specifically, the second preset data table is pre-built and stores preset temperature differences and corresponding preset correction coefficients.

[0120] Once the first temperature difference before and after the first nitrogen oxide treatment device A1 is calculated, the corresponding correction coefficient can be found in the second preset data table.

[0121] S1134: Correct the first initial urea injection amount according to the correction coefficient to obtain the first urea injection amount.

[0122] When correcting the initial urea injection quantity, the correction factor is directly multiplied by the initial urea injection quantity.

[0123] This application uses the temperature values ​​before and after the first nitrogen oxide treatment device A1 to correct the urea injection amount, thereby further precisely controlling the urea injection amount and improving the conversion efficiency.

[0124] S12: Calculate the first concentration ratio of nitrogen dioxide concentration to total nitrogen oxide concentration before the second nitrogen oxide treatment device to the second nitrogen oxide treatment device based on the second temperature before the particle capture device A2 and the third temperature after the particle capture device A2.

[0125] Specifically, S12 (calculating the first concentration ratio of nitrogen dioxide concentration to total nitrogen oxide concentration before the second nitrogen oxide treatment device based on the second temperature before and the third temperature after the particulate capture device A2) includes the following steps:

[0126] S120: Calculate the weighted temperature value based on the second temperature before the particle capture device and the third temperature after it;

[0127] S121: Based on the weighted temperature value and the second air velocity of the particle capture device, query the third preset data table for the initial concentration ratio of nitrogen dioxide concentration to total nitrogen oxide concentration before the second nitrogen oxide treatment device corresponding to the weighted temperature value and the second air velocity. The third preset data table stores the preset temperature value, the preset air velocity, and the corresponding preset concentration ratio of nitrogen dioxide concentration to total nitrogen oxide concentration.

[0128] S122: Correct the initial concentration ratio based on the nitrogen oxide concentration before the particulate capture device to obtain a first concentration ratio of nitrogen dioxide concentration to total nitrogen oxide concentration before the second nitrogen oxide treatment device.

[0129] S13: Calculate the second urea injection rate before the second nitrogen oxide treatment device based on the first concentration ratio of nitrogen dioxide concentration to total nitrogen oxide concentration before the second nitrogen oxide treatment device and the third temperature before the second nitrogen oxide treatment device.

[0130] Specifically, S13 (calculating the second urea injection rate before the second nitrogen oxide treatment device based on the first concentration ratio of nitrogen dioxide concentration to total nitrogen oxide concentration before the second nitrogen oxide treatment device and the third temperature before the second nitrogen oxide treatment device) includes the following steps:

[0131] S131: The third temperature before the second nitrogen oxide treatment device and the third space velocity of the second nitrogen oxide treatment device are used to query the corresponding nitrogen oxide conversion efficiency in the fourth preset data table; wherein, the fourth preset data table stores the preset temperature, preset space velocity, and preset nitrogen oxide conversion efficiency corresponding to the preset temperature and preset space velocity.

[0132] S132: The first concentration ratio of nitrogen dioxide concentration before the second nitrogen oxide treatment device to the total nitrogen oxide concentration corrects the nitrogen oxide conversion efficiency of the second nitrogen oxide treatment device;

[0133] S132: Calculate the second urea injection rate before the second nitrogen oxide treatment device based on the modified nitrogen oxide conversion efficiency of the second nitrogen oxide treatment device, the exhaust gas quality, and the nitrogen dioxide concentration before the second nitrogen oxide treatment device.

[0134] In another embodiment of this application, such as Figure 4 As shown, S3 (determining whether the first nitrogen oxide treatment unit A1 should trigger the regeneration function based on the total hydrocarbon content, total sulfur content, actual conversion rate of nitrogen oxides in the preceding stage, and actual conversion rate of nitrogen oxides in the subsequent stage) specifically includes the following steps:

[0135] S31: Determine the preset hydrocarbon conversion rate at the average temperature based on the average temperature in the first nitrogen oxide treatment device; calculate the total hydrocarbon amount of the first nitrogen oxide treatment device A1 based on the amount of hydrocarbon emitted by the engine, the preset hydrocarbon conversion rate, and the amount of hydrocarbon escape stored in the first nitrogen oxide treatment device.

[0136] Specifically, the average temperature in the first nitrogen oxide treatment device can be calculated as follows: the average temperature is calculated based on the first temperature before the first nitrogen oxide treatment device and the second temperature after the first nitrogen oxide treatment device.

[0137] The amount of hydrocarbon escape stored in the first nitrogen oxide treatment unit can be obtained by looking up a preset data table based on the average temperature.

[0138] The preset hydrocarbon conversion rate can be obtained by looking up the preset data table based on the average temperature.

[0139] Specifically, the amount of hydrocarbons stored in the first nitrogen oxide treatment device A1 = the amount of hydrocarbons emitted by the engine * (1 - preset hydrocarbon conversion rate) - hydrocarbon escape amount;

[0140] After calculating the amount of hydrocarbons stored in the first nitrogen oxide processing device A1, the total amount of hydrocarbons can be obtained by time integration.

[0141] If the total amount of hydrocarbons in the first nitrogen oxide treatment device A1 exceeds the preset total amount, the regeneration function is triggered.

[0142] S32: Calculate the sulfur storage amount based on the average temperature in the first nitrogen oxide treatment unit, and calculate the total sulfur amount based on the sulfur storage amount;

[0143] First, the original sulfur content is determined by engine speed and fuel quantity. Then, the sulfur storage in the first nitrogen oxide treatment device is calculated based on the average temperature in the first nitrogen oxide treatment device. Finally, the total sulfur in the first nitrogen oxide treatment device is obtained by integrating over time.

[0144] If the total sulfur content in the first nitrogen oxide treatment device A1 exceeds the preset poisoning level, the regeneration function is triggered.

[0145] S33: The regeneration function is triggered when the actual conversion rate of nitrogen oxides in the preceding stage is less than the first preset conversion rate, or the actual conversion rate of nitrogen oxides in the subsequent stage is greater than the second preset conversion rate.

[0146] When HC or sulfur poisoning occurs, the actual conversion efficiency of nitrogen oxides decreases. To maintain the same emission ratio, the closed-loop system increases the urea injection rate, leading to excessive urea correction in the closed-loop system. Therefore, by increasing the conversion efficiency to determine whether to trigger the regeneration function, the excessive urea injection rate correction caused by inaccurate total hydrocarbon or sulfur content can be reduced.

[0147] When the regeneration function is triggered, the injected fuel is burned in the first nitrogen oxide treatment device A1. When the average temperature of the first temperature before the first nitrogen oxide treatment device A1 and the second temperature after the first nitrogen oxide treatment device A1 exceeds the target temperature for a certain period of time, it can be considered that desulfurization and deHC removal have been completed, and the regeneration function is terminated.

[0148] In another embodiment of this application, after step S4 (calculating the feedforward oil quantity of the first nitrogen oxide treatment device based on the first temperature before the first nitrogen oxide treatment device, the target temperature, the exhaust gas mass flow rate, and the exhaust gas specific heat capacity), it is necessary to correct the feedforward oil quantity. The specific correction method for the feedforward oil quantity includes the following:

[0149] (1) Determine the first correction value based on the target temperature and the mass flow rate of the exhaust gas; specifically, a preset correction table can be pre-constructed, which stores the preset temperature, the preset mass flow rate of the exhaust gas and the corresponding preset correction value. Once the target temperature is determined and the mass flow rate of the exhaust gas is detected, the corresponding first correction value can be obtained from the preset correction table.

[0150] The feedforward oil quantity is adjusted based on the first correction value. Once the first correction value is determined, it can be directly summed with the feedforward oil quantity to obtain the corrected feedforward oil quantity.

[0151] (2) Calculate the total hydrocarbon conversion rate based on the hydrocarbon conversion rate of the first nitrogen oxide treatment device and the hydrocarbon conversion rate of the particulate capture device; specifically, by calibrating the HC conversion efficiency MAP of the first nitrogen oxide treatment device A1 and the particulate capture device A2, calculate the first hydrocarbon conversion efficiency of the first nitrogen oxide treatment device A1 and the second hydrocarbon conversion efficiency of the particulate capture device A2, and then calculate the total hydrocarbon conversion rate based on the first hydrocarbon conversion efficiency and the second hydrocarbon conversion efficiency. The total hydrocarbon conversion rate = 1 - (1 - first hydrocarbon conversion efficiency) * (1 - second hydrocarbon conversion efficiency).

[0152] The feedforward oil quantity is corrected based on the total hydrocarbon conversion rate to obtain the corrected feedforward oil quantity. Once the total hydrocarbon conversion rate is calculated, the feedforward oil quantity calculated in S4 is divided by the total hydrocarbon conversion rate to obtain the corrected feedforward oil quantity.

[0153] After the current feed rate is corrected, in S5, the corrected feed rate of fuel is injected into the first nitrogen oxide treatment device, and the first nitrogen oxide treatment device is controlled to enter the regeneration mode.

[0154] As a third aspect of this application, this application also provides an exhaust gas purification aftertreatment controller, such as... Figure 5 As shown, the exhaust gas purification and aftertreatment controller 100 includes:

[0155] The first calculation module 101 is used to calculate the first urea injection amount before the first nitrogen oxide and the second urea injection amount before the second nitrogen oxide based on the first temperature before the first nitrogen oxide treatment device, the first nitrogen oxide concentration, the second temperature before the particle capture device and the third temperature after it.

[0156] Specifically, the first calculation module 101 is used to execute S1 in the exhaust gas purification and after-treatment control method described above.

[0157] The first control module 102 is used to control the first nitrogen oxide treatment device to spray urea according to the first urea injection amount, and to control the second nitrogen oxide treatment device to spray urea according to the second urea injection amount.

[0158] Specifically, the first control module 102 is used to execute S2 in the exhaust gas purification and after-treatment control method described above.

[0159] The regeneration control module 103 is used to determine whether the first nitrogen oxide treatment device A1 triggers the regeneration function based on the total hydrocarbon content, total sulfur content, actual nitrogen oxide conversion rate of the pre-stage and the actual nitrogen oxide conversion rate of the post-stage nitrogen oxide treatment device A1; when it is determined that the first nitrogen oxide treatment device triggers the regeneration function, it calculates the feed oil quantity of the first nitrogen oxide treatment device based on the first temperature before the first nitrogen oxide treatment device, the target temperature, the exhaust gas mass flow rate and the exhaust gas specific heat capacity; and injects the feed oil quantity of fuel into the first nitrogen oxide treatment device, and controls the first nitrogen oxide treatment device to enter the regeneration mode.

[0160] Specifically, the regeneration control module 103 is used to execute S3-S5 in the exhaust gas purification and after-treatment control method described above.

[0161] The exhaust gas purification aftertreatment controller provided in this application uses the first temperature and target temperature before the first nitrogen oxide treatment device when calculating the feedforward oil quantity. Since the first temperature is stable, the calculated feedforward oil quantity will not have a large deviation, thereby making the exhaust gas temperature in the first nitrogen oxide treatment device A1 uniform. When the exhaust gas enters the particulate capture device A2, the oxidation and combustion of particulate matter can be fully achieved, which improves the ability of the regenerated DPF to capture particulate matter, thereby improving the regeneration efficiency.

[0162] The methods in this application can be implemented, in whole or in part, by software, hardware, firmware, or any combination thereof. When implemented in software, they can be implemented, in whole or in part, as a computer program product. This computer program product includes one or more computer programs or instructions, which, when loaded and executed on a computer, perform all or part of the processes or functions of this application. The computer can be a general-purpose computer, a special-purpose computer, a computer network, network equipment, user equipment, core network equipment, OAM, or other programmable device.

[0163] Computer program products can be written in any combination of one or more programming languages ​​to perform the operations of the embodiments of this application. The programming languages ​​include object-oriented programming languages ​​such as Java and C++, as well as conventional procedural programming languages ​​such as C or similar languages. The program code can be executed entirely on the user's computing device, partially on the user's computing device, as a standalone software package, partially on the user's computing device and partially on a remote computing device, or entirely on a remote computing device or server.

[0164] Computer programs or instructions can be stored in or transferred from one computer-readable storage medium to another. For example, a computer program or instructions can be transferred from one website, computer, server, or data center to another via wired or wireless means. A computer-readable storage medium can be any usable medium that a computer can access, or a data storage device such as a server or data center that integrates one or more usable media. Usable media can be magnetic media, such as floppy disks, hard disks, and magnetic tapes; optical media, such as digital video discs; or semiconductor media, such as solid-state drives. The computer-readable storage medium can be volatile or non-volatile, or may include both types.

[0165] Furthermore, embodiments of this application may also be storage media storing a computer program, which is executed by a processor of the steps in an exhaust gas purification and aftertreatment control method described in any of the above embodiments of this specification.

[0166] For the foregoing method embodiments, in order to simplify the description, they are all described as a series of actions. However, those skilled in the art should understand that this application is not limited to the described order of actions, because according to this application, some steps can be performed in other orders or simultaneously. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily essential to this application.

[0167] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For apparatus embodiments, since they are basically similar to method embodiments, the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments.

[0168] The steps in the methods of the various embodiments of this application can be adjusted, combined, or deleted according to actual needs, and the technical features described in each embodiment can be replaced or combined. The apparatuses in the various embodiments of this application can be combined, divided, or deleted according to actual needs.

[0169] Those skilled in the art will further recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0170] The steps of the methods or algorithms described in conjunction with the embodiments disclosed herein can be implemented directly by hardware, a software unit executed by a processor, or a combination of both. The software unit can be located in random access memory (RAM), main memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art.

[0171] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0172] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for controlling exhaust gas purification and post-treatment, characterized in that, The control method is applicable to a post-treatment system, which includes: a first nitrogen oxide treatment device, employing a reducing catalyst and an oxidizing catalyst, using sprayed urea to reduce nitrogen oxides and oxidize ammonia; a particulate capture device, employing an oxidizing catalyst to capture particles and nitrogen oxides; and a second nitrogen oxide treatment device, employing a reducing catalyst and an oxidizing catalyst, using sprayed urea to reduce nitrogen oxides and oxidize ammonia. The control method includes: Based on the first temperature before the first nitrogen oxide treatment device, the first nitrogen oxide concentration, the second temperature before the particle capture device, and the third temperature after the particle capture device, calculate the first urea injection rate before the first nitrogen oxide treatment device and the second urea injection rate before the second nitrogen oxide treatment device. The injection of urea from the first nitrogen oxide treatment device is controlled according to the first urea injection volume, and the injection of urea from the second nitrogen oxide treatment device is controlled according to the second urea injection volume. Based on the total amount of carbon and hydrogen, the total amount of sulfur, the actual conversion rate of nitrogen oxides in the pre-stage and the actual conversion rate of nitrogen oxides in the post-stage of the first nitrogen oxide treatment device, it is determined whether the first nitrogen oxide treatment device triggers the regeneration function. When it is determined that the first nitrogen oxide treatment device triggers the regeneration function, the feed oil quantity of the first nitrogen oxide treatment device is calculated based on the first temperature before the first nitrogen oxide treatment device, the target temperature, the exhaust gas mass flow rate and the exhaust gas specific heat capacity. Inject the feedforward fuel quantity into the first nitrogen oxide treatment device, and control the first nitrogen oxide treatment device to enter the regeneration mode; The step of calculating the first urea injection rate before the first nitrogen oxide treatment device and the second urea injection rate before the second nitrogen oxide treatment device based on the first temperature before the first nitrogen oxide treatment device, the first nitrogen oxide concentration, the second temperature before the particulate capture device, and the third temperature after the particulate capture device includes: The first urea injection rate before the first nitrogen oxide treatment device is calculated based on the first temperature and the first nitrogen oxide concentration before the first nitrogen oxide treatment device. Based on the second temperature before the particle capture device and the third temperature after it, calculate the first concentration ratio of nitrogen dioxide concentration to total nitrogen oxide concentration before the second nitrogen oxide treatment device. The second urea injection rate before the second nitrogen oxide treatment device is calculated based on the first concentration ratio of nitrogen dioxide concentration to total nitrogen oxide concentration before the second nitrogen oxide treatment device and the third temperature before the second nitrogen oxide treatment device. The step of calculating the first urea injection rate before the first nitrogen oxide treatment device based on the first temperature and the first nitrogen oxide concentration before the first nitrogen oxide treatment device includes: The feedforward nitrogen oxide conversion efficiency is queried from a first preset data table based on the first temperature before the first nitrogen oxide treatment device and the air velocity in the first nitrogen oxide treatment device; wherein, the first preset data table stores a preset temperature, a preset air velocity, and a preset nitrogen oxide conversion efficiency corresponding to the preset temperature and the preset air velocity. Calculate the feedforward nitrogen oxide mass flow rate of the first nitrogen oxide treatment device based on the first nitrogen oxide concentration and the exhaust gas mass flow rate before the first nitrogen oxide treatment device. Calculate the mass flow rate of hydrogen nitride based on the feedforward mass flow rate of nitrogen oxides from the first nitrogen oxide treatment device; The first urea injection rate before the first nitrogen oxide treatment device is calculated based on the mass flow rate of the hydrogen nitride.

2. The exhaust gas purification and post-treatment control method according to claim 1, characterized in that, The calculation of the first urea injection quantity before the first nitrogen oxide treatment device based on the mass flow rate of the hydrogen nitride includes: Calculate the initial urea injection rate before the first nitrogen oxide treatment device based on the mass flow rate of the hydrogen nitride. The first temperature difference is calculated based on the first temperature before the first nitrogen oxide treatment device and the second temperature after it. The correction coefficient corresponding to the first temperature difference is queried in the second preset data table according to the first temperature difference. The second preset data table stores the preset temperature difference and the preset correction coefficient corresponding to the preset temperature difference. The first initial urea injection amount is adjusted according to the correction coefficient to obtain the first urea injection amount.

3. The exhaust gas purification and post-treatment control method according to claim 1, characterized in that, The calculation of the first concentration ratio of nitrogen dioxide concentration to total nitrogen oxide concentration before the second nitrogen oxide treatment device based on the second temperature before the particle capture device and the third temperature after the particle capture device includes: The weighted temperature value is calculated based on the second temperature before the particle capture device and the third temperature after it. Based on the weighted temperature value and the second air velocity of the particle capture device, the initial concentration ratio of nitrogen dioxide concentration to total nitrogen oxide concentration before the second nitrogen oxide treatment device corresponding to the weighted temperature value and the second air velocity is queried in the third preset data table. The third preset data table stores preset temperature value, preset air velocity and the corresponding preset concentration ratio of nitrogen dioxide concentration to total nitrogen oxide concentration. The initial concentration ratio is corrected based on the nitrogen oxide concentration before the particle capture device to obtain a first concentration ratio of nitrogen dioxide concentration to total nitrogen oxide concentration before the second nitrogen oxide treatment device.

4. The exhaust gas purification and post-treatment control method according to claim 1, characterized in that, The step of calculating the second urea injection rate before the second nitrogen oxide treatment device based on the first concentration ratio of nitrogen dioxide concentration to total nitrogen oxide concentration before the second nitrogen oxide treatment device and the third temperature before the second nitrogen oxide treatment device includes: The third temperature before the second nitrogen oxide treatment device and the third space velocity of the second nitrogen oxide treatment device are used to look up the corresponding nitrogen oxide conversion efficiency in the fourth preset data table; wherein, the fourth preset data table stores preset temperature, preset space velocity, and preset nitrogen oxide conversion efficiency corresponding to the preset temperature and preset space velocity. The nitrogen oxide conversion efficiency of the second nitrogen oxide treatment device is corrected based on a first concentration ratio of nitrogen dioxide concentration to total nitrogen oxide concentration before the second nitrogen oxide treatment device. The second urea injection rate before the second nitrogen oxide treatment device is calculated based on the nitrogen oxide conversion efficiency of the modified second nitrogen oxide treatment device, the exhaust gas quality, and the nitrogen dioxide concentration before the second nitrogen oxide treatment device.

5. The exhaust gas purification and post-treatment control method according to claim 1, characterized in that, The step of determining whether the first nitrogen oxide treatment device should trigger the regeneration function based on the total hydrocarbon content, total sulfur content, actual nitrogen oxide conversion rate of the preceding stage, and actual nitrogen oxide conversion rate of the following stage includes: A preset hydrocarbon conversion rate at the average temperature is determined based on the average temperature in the first nitrogen oxide treatment device; the total hydrocarbon amount of the first nitrogen oxide treatment device is calculated based on the amount of hydrocarbons emitted by the engine, the preset hydrocarbon conversion rate, and the amount of hydrocarbons that escaped stored in the first nitrogen oxide treatment device. The sulfur storage amount is calculated based on the average temperature in the first nitrogen oxide treatment unit, and the total sulfur amount is calculated based on the sulfur storage amount. When the total amount of hydrocarbons in the first nitrogen oxide treatment device is greater than a preset total amount, or the total amount of sulfur in the first nitrogen oxide treatment device is greater than a preset poisoning amount, or the actual conversion rate of the preceding nitrogen oxides is less than a first preset conversion rate, or the actual conversion rate of the following nitrogen oxides is greater than a second preset conversion rate, the regeneration function is triggered.

6. The exhaust gas purification and post-treatment control method according to claim 1, characterized in that, After calculating the feedforward oil quantity of the first nitrogen oxide treatment device based on the first temperature before the first nitrogen oxide treatment device, the target temperature, the exhaust gas mass flow rate, and the exhaust gas specific heat capacity, the control method further includes: A first correction value is determined based on the target temperature and the exhaust gas mass flow rate; The feedforward oil quantity is adjusted according to the first correction value.

7. The exhaust gas purification and post-treatment control method according to claim 1, characterized in that, After calculating the feedforward oil quantity of the first nitrogen oxide treatment device based on the first temperature before the first nitrogen oxide treatment device, the target temperature, the exhaust gas mass flow rate, and the exhaust gas specific heat capacity, the control method further includes: The total hydrocarbon conversion rate is calculated based on the hydrocarbon conversion rate of the first nitrogen oxide treatment device and the hydrocarbon conversion rate of the particulate capture device. The feedforward oil quantity is corrected based on the total hydrocarbon conversion rate to obtain the corrected feedforward oil quantity.

8. An exhaust gas purification and aftertreatment controller, characterized in that, include The first calculation module is used to calculate the first urea injection rate before the first nitrogen oxide treatment device and the second urea injection rate before the second nitrogen oxide treatment device based on the first temperature before the first nitrogen oxide treatment device, the first nitrogen oxide concentration, the second temperature before the particle capture device and the third temperature after it. The first control module is used to control the first nitrogen oxide treatment device to spray urea according to the first urea injection volume, and to control the second nitrogen oxide treatment device to spray urea according to the second urea injection volume. The regeneration control module is used to determine whether the first nitrogen oxide treatment device should trigger the regeneration function based on the total hydrocarbon content, total sulfur content, actual nitrogen oxide conversion rate of the pre-stage and the actual nitrogen oxide conversion rate of the post-stage nitrogen oxide treatment device; when it is determined that the first nitrogen oxide treatment device has triggered the regeneration function, the module calculates the feed oil quantity of the first nitrogen oxide treatment device based on the first temperature before the first nitrogen oxide treatment device, the target temperature, the exhaust gas mass flow rate, and the exhaust gas specific heat capacity; injects the feed oil quantity of fuel into the first nitrogen oxide treatment device; and controls the first nitrogen oxide treatment device to enter the regeneration mode. The step of calculating the first urea injection rate before the first nitrogen oxide treatment device and the second urea injection rate before the second nitrogen oxide treatment device based on the first temperature before the first nitrogen oxide treatment device, the first nitrogen oxide concentration, the second temperature before the particulate capture device, and the third temperature after the particulate capture device includes: The first urea injection rate before the first nitrogen oxide treatment device is calculated based on the first temperature and the first nitrogen oxide concentration before the first nitrogen oxide treatment device. Based on the second temperature before the particle capture device and the third temperature after it, calculate the first concentration ratio of nitrogen dioxide concentration to total nitrogen oxide concentration before the second nitrogen oxide treatment device. The second urea injection rate before the second nitrogen oxide treatment device is calculated based on the first concentration ratio of nitrogen dioxide concentration to total nitrogen oxide concentration before the second nitrogen oxide treatment device and the third temperature before the second nitrogen oxide treatment device. The step of calculating the first urea injection rate before the first nitrogen oxide treatment device based on the first temperature and the first nitrogen oxide concentration before the first nitrogen oxide treatment device includes: The feedforward nitrogen oxide conversion efficiency is queried from a first preset data table based on the first temperature before the first nitrogen oxide treatment device and the air velocity in the first nitrogen oxide treatment device; wherein, the first preset data table stores a preset temperature, a preset air velocity, and a preset nitrogen oxide conversion efficiency corresponding to the preset temperature and the preset air velocity. Calculate the feedforward nitrogen oxide mass flow rate of the first nitrogen oxide treatment device based on the first nitrogen oxide concentration and the exhaust gas mass flow rate before the first nitrogen oxide treatment device. Calculate the mass flow rate of hydrogen nitride based on the feedforward mass flow rate of nitrogen oxides from the first nitrogen oxide treatment device; The first urea injection rate before the first nitrogen oxide treatment device is calculated based on the mass flow rate of the hydrogen nitride.

9. An exhaust gas purification and after-treatment system, characterized in that, include: The first nitrogen oxide treatment unit uses a reducing catalyst and an oxidizing catalyst to reduce nitrogen oxides and oxidize ammonia by spraying urea. The particle capture device uses an oxidizing catalyst to capture particles and nitrides; The second nitrogen oxide treatment unit uses a reducing catalyst and an oxidizing catalyst to reduce nitrogen oxides and oxidize ammonia by spraying urea. Temperature sensors are used to detect the temperature of exhaust gas at different stages; Nitrogen oxide sensors are used to detect the concentration of nitrogen oxides in exhaust gas at different stages; and The post-processing controller as described in claim 8.

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