Tail emission control method, device thereof, and diesel engine after-treatment system

Abstract

The present application provides a method for controlling exhaust emissions, a device therefor, and a diesel engine aftertreatment system. The method comprises: first, obtaining the concentration of ammonia entering the SCR, which uses ammonia to reduce the concentration of nitrogen oxides in the exhaust gas; then, determining whether the ammonia concentration is greater than a predetermined concentration. If the ammonia concentration is greater than the predetermined concentration, controlling the outlet of the control valve connected to the second pipeline to close and the outlet of the control valve connected to the first pipeline to open, so that the exhaust gas is discharged from the first pipeline through the filter. The method determines whether the concentration of ammonia entering the SCR is greater than a predetermined concentration, and if the ammonia concentration is greater than the predetermined concentration, controlling the outlet of the intelligent control valve connected to the second pipeline to close, so that the exhaust gas passes from the outlet of the ASC to the inlet of the filter through the first pipeline, so that excess ammonia is adsorbed by the filter, thereby achieving the purpose of reducing PN emissions, thereby solving the problem of PN emissions easily exceeding the standard in the prior art.

Description

Technical Field

[0001] The present application relates to the technical field of diesel engine exhaust emission aftertreatment, and specifically to an exhaust emission control method, an exhaust emission control device, a computer-readable storage medium, an electronic device, and a diesel engine aftertreatment system. Background Art

[0002] Diesel engines, with their excellent economy and power, are widely used in transportation, agricultural machinery, and construction machinery. However, their inherent combustion characteristics lead to serious exhaust emissions, which have significant impacts on humans and the environment. The most prominent of these emissions is particulate matter (PM). With increasingly stringent diesel engine emission regulations, PM mass limits and PN (particle number) limits are becoming increasingly stringent. In-engine purification technologies are no longer able to meet these limits. PN refers to the total number of particles larger than 23 nm in the diluted exhaust gas after volatile matter has been removed. Exhaust after-treatment catalysts, including DOC (diesel oxidation catalyst), DPF (diesel particulate filter), SCR (selective catalytic reduction), and ASR (ammonia slip catalyst), have become essential features of diesel engines.

[0003] The DPF filters and captures particulate matter from engine exhaust through diffusion, deposition, and impaction mechanisms, reducing tailpipe PN values. Exhaust particulate matter is primarily composed of tiny particles of carbon and carbides. Over time, excessive urea injection, high DPF upstream temperatures, and low carbon loading can lead to elevated PN emissions, posing a risk of exceeding standards.

[0004] Therefore, there is an urgent need for a post-processing method for PN emissions to solve the above problems. Summary of the Invention

[0005] The main purpose of this application is to provide a method for controlling exhaust emissions, an exhaust emission control device, a computer-readable storage medium, an electronic device, and a diesel engine aftertreatment system, so as to at least solve the problem of PN emissions easily exceeding the standard in the prior art.

[0006] To achieve the above-mentioned purpose, according to one aspect of the present application, a method for controlling exhaust emissions is provided, which is applied to a diesel engine aftertreatment system, wherein the diesel engine aftertreatment system at least includes an SCR, an ASC, a control valve and a filter connected in sequence, the outlet of the ASC is connected to the inlet of the filter via a first pipeline, the outlet of the ASC is connected to the outlet of the filter via a second pipeline, the control valve is arranged on the first pipeline and on the second pipeline, and the method includes: obtaining the ammonia concentration introduced into the SCR, the SCR using ammonia to reduce the concentration of nitrogen oxides in the exhaust gas; determining whether the ammonia concentration is greater than a predetermined concentration, and when the ammonia concentration is greater than the predetermined concentration, controlling the outlet of the control valve connected to the second pipeline to be closed and controlling the outlet of the control valve connected to the first pipeline to be open, so that the exhaust gas is discharged from the first pipeline through the filter, so that excess ammonia is adsorbed by the filter.

[0007] Optionally, after determining whether the ammonia concentration is greater than a predetermined concentration, the method further includes: when the ammonia concentration is not greater than the predetermined concentration, controlling the outlet of the control valve connected to the second pipeline to be open and controlling the outlet of the control valve connected to the first pipeline to be closed, so that the exhaust gas is discharged from the second pipeline.

[0008] Optionally, the diesel engine after-treatment device further includes a DPF, an outlet of the DPF being connected to an inlet of the SCR, and the method further includes: obtaining a carbon load in the DPF; determining whether the carbon load is within a predetermined range, and when the carbon load is less than a minimum value of the predetermined range or greater than a maximum value of the predetermined range, controlling the outlet of the control valve connected to the second pipeline to be closed and controlling the outlet of the control valve connected to the first pipeline to be open, so that the exhaust gas is discharged from the first pipeline through the filter, so that the particles in the exhaust gas are adsorbed by the filter, and when the carbon load is within the predetermined range, controlling the outlet of the control valve connected to the second pipeline to be open and controlling the outlet of the control valve connected to the first pipeline to be closed, so that the exhaust gas is discharged from the second pipeline.

[0009] Optionally, the method further includes: obtaining the inlet temperature of the DPF; determining whether the inlet temperature is greater than a temperature threshold; if the inlet temperature is greater than the temperature threshold, controlling the outlet of the control valve connected to the second pipeline to be closed and controlling the outlet of the control valve connected to the first pipeline to be open, so that the exhaust gas is discharged from the first pipeline through the filter, so that the particles in the exhaust gas are adsorbed by the filter; if the inlet temperature is not greater than the temperature threshold, controlling the outlet of the control valve connected to the second pipeline to be open and controlling the outlet of the control valve connected to the first pipeline to be closed, so that the exhaust gas is discharged from the second pipeline.

[0010] Optionally, the diesel engine aftertreatment device further includes a PN measuring device, which is connected to the outlet of the ASC. The method further includes: obtaining a PN value of the exhaust gas tested by the PN measuring device, where the PN value is the value of the amount of particulate matter in the exhaust gas; determining whether the PN value is greater than a predetermined value, and if the PN value is greater than the predetermined value, controlling the outlet of the control valve connected to the second pipeline to be closed and controlling the outlet of the control valve connected to the first pipeline to be open, so that the exhaust gas is discharged from the first pipeline through the filter, so that the particles in the exhaust gas are adsorbed by the filter; and if the PN value is not greater than the predetermined value, controlling the outlet of the control valve connected to the second pipeline to be open and controlling the outlet of the control valve connected to the first pipeline to be closed, so that the exhaust gas is discharged from the second pipeline.

[0011] Optionally, the diesel engine aftertreatment device further includes a liquid storage tank connected to the SCR. Obtaining the ammonia concentration passed into the SCR includes: obtaining the urea concentration of a urea aqueous solution passed into the SCR, where the urea aqueous solution is sprayed into the SCR from the liquid storage tank; and calculating the concentration of ammonia generated after urea decomposition based on the urea concentration and a chemical formula for urea hydrolysis to obtain the ammonia concentration.

[0012] Optionally, a one-way valve is provided on the second pipeline, and the outlet of the control valve connected to the second pipeline is controlled to be opened and the outlet of the control valve connected to the first pipeline is controlled to be closed so that the exhaust gas is discharged from the second pipeline, including: controlling the control valve and the one-way valve to be opened so that the exhaust gas is discharged from the second pipeline.

[0013] According to another aspect of the present application, a device for controlling exhaust emissions is provided, which is applied to a diesel engine aftertreatment system, wherein the diesel engine aftertreatment system comprises at least an SCR, an ASC, a control valve and a filter connected in sequence, the outlet of the ASC is connected to the inlet of the filter via a first pipeline, the outlet of the ASC is connected to the outlet of the filter via a second pipeline, the control valve is arranged on the first pipeline and on the second pipeline, the device comprises a first acquisition unit and a first control unit, wherein the first acquisition unit is used to obtain the concentration of ammonia passing into the SCR, and the SCR uses ammonia to reduce the concentration of nitrogen oxides in the exhaust gas; the first control unit is used to determine whether the ammonia concentration is greater than a predetermined concentration, and when the ammonia concentration is greater than the predetermined concentration, the outlet of the control valve connected to the second pipeline is controlled to be closed and the outlet of the control valve connected to the first pipeline is controlled to be open, so that the exhaust gas is discharged from the first pipeline through the filter, so that excess ammonia is adsorbed by the filter.

[0014] According to another aspect of the present application, a computer-readable storage medium is provided, which includes a stored program, wherein when the program is run, the device where the computer-readable storage medium is located is controlled to execute any one of the exhaust emission control methods.

[0015] According to another aspect of the present application, an electronic device is provided, comprising: one or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, and the one or more programs include methods for executing any one of the exhaust emission control methods.

[0016] According to another aspect of the present application, a diesel engine aftertreatment system is provided, comprising at least a controller, an SCR, an ASC, a control valve, and a filter connected in sequence, wherein the outlet of the ASC is connected to the inlet of the filter via a first pipeline, the outlet of the ASC is connected to the outlet of the filter via a second pipeline, the control valve is arranged on the first pipeline and on the second pipeline, and the controller is used to execute any one of the exhaust emission control methods described.

[0017] Optionally, the filter comprises a DPF without precious metal coating and having a high porosity.

[0018] Applying the technical solution of the present application, the exhaust emission control method is applied to a diesel engine aftertreatment system, wherein the diesel engine aftertreatment system at least includes an SCR, an ASC, a control valve and a filter connected in sequence, the outlet of the ASC is connected to the inlet of the filter through a first pipeline, the outlet of the ASC is connected to the outlet of the filter through a second pipeline, the control valve is arranged on the first pipeline and on the second pipeline, and in the exhaust emission control method, first, the ammonia concentration introduced into the SCR is obtained, and the SCR uses ammonia to reduce the concentration of nitrogen oxides in the exhaust gas; then, it is determined whether the ammonia concentration is greater than a predetermined concentration. When the ammonia concentration is greater than the predetermined concentration, the outlet of the control valve connected to the second pipeline is controlled to be closed and the outlet of the control valve connected to the first pipeline is controlled to be open, so that the exhaust gas is discharged from the first pipeline through the filter, so that excess ammonia is adsorbed by the filter. The method determines whether the ammonia concentration entering the SCR is greater than a predetermined concentration. If the ammonia concentration is greater than the predetermined concentration, the outlet of the intelligent control valve connected to the second pipeline is closed, so that the exhaust gas passes from the outlet of the ASC to the inlet of the filter through the first pipeline, so that excess ammonia is adsorbed by the filter, thereby achieving the purpose of reducing PN emissions and solving the problem of PN emissions easily exceeding the standard in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The drawings that constitute part of this application are used to provide a further understanding of this application. The illustrative embodiments of this application and their descriptions are used to explain this application and do not constitute an improper limitation on this application. In the drawings:

[0020] Figure 1 A hardware structure block diagram of a mobile terminal for executing a method for controlling exhaust emissions provided in an embodiment of the present application is shown;

[0021] Figure 2 A diesel engine aftertreatment system according to an embodiment of the present application is shown;

[0022] Figure 3 A schematic flow chart of a method for controlling exhaust emissions according to an embodiment of the present application is shown;

[0023] Figure 4 A schematic flow chart of a method for controlling exhaust emissions according to another embodiment of the present application is shown;

[0024] Figure 5 A diesel engine aftertreatment system according to another embodiment of the present application is shown;

[0025] Figure 6 A diesel engine aftertreatment system according to another embodiment of the present application is shown;

[0026] Figure 7 A diesel engine aftertreatment system according to another embodiment of the present application is shown;

[0027] Figure 8 A diesel engine aftertreatment system according to another embodiment of the present application is shown;

[0028] Figure 9 A schematic flow chart of a method for controlling exhaust emissions according to another embodiment of the present application is shown;

[0029] Figure 10 A structural block diagram of an exhaust emission control device provided according to an embodiment of the present application is shown.

[0030] The above drawings include the following reference numerals:

[0031] 102. Processor; 104. Memory; 106. Transmission device; 108. Input / output device; 201. SCR; 202. ASC; 203. Control valve; 204. Filter; 205. DPF; 206. PN measurement device; 207. One-way valve; 208. DOC; 301. First pipeline; 302. Second pipeline. DETAILED DESCRIPTION

[0032] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0033] In order to enable those skilled in the art to better understand the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of this application.

[0034] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0035] For ease of description, some nouns or terms involved in the embodiments of the present application are explained below:

[0036] PN: Refers to the number of particles in vehicle exhaust emissions. Specifically, according to the test method specified in the national standard GB17691, it is the total number of particles with a diameter greater than 23nm in the diluted exhaust gas after removing volatile substances.

[0037] SCR: Selective catalytic reduction refers to the use of a reducing agent (such as ammonia) to "selectively" react with nitrogen oxides in exhaust gas under the action of a catalyst to produce non-toxic and non-polluting nitrogen and water.

[0038] ASC: Ammonia slip catalyst, a type of exhaust aftertreatment for diesel vehicles, is installed at the rear end of the SCR and is a device that reduces ammonia leakage from the exhaust at the rear end of the SCR through catalytic oxidation.

[0039] DPF: A particulate filter used to reduce carbon soot emissions from National VI diesel engines and to reduce PN emissions.

[0040] Particulate matter: The particulate matter contained in the engine exhaust generally includes two components: soot and ash. Soot generally refers to the part that can be burned through regeneration, and ash generally refers to the incombustible component. It will continue to accumulate in the DPF. When it reaches a certain accumulation amount, it needs to be cleaned at a service station.

[0041] As introduced in the background technology, PN emissions in the prior art are prone to exceeding the standard. To solve the above problem, the embodiments of the present application provide an exhaust emission control method, an exhaust emission control device, a computer-readable storage medium, an electronic device, and a diesel engine aftertreatment system.

[0042] The technical solutions in the embodiments of the present invention will be described clearly and completely below with reference to the accompanying drawings in the embodiments of the present invention.

[0043] The method embodiments provided in the embodiments of the present application can be executed in a mobile terminal, a computer terminal or a similar computing device. Taking running on a mobile terminal as an example, Figure 1 This is a hardware structure block diagram of a mobile terminal of a method for controlling exhaust emissions according to an embodiment of the present invention. Figure 1 As shown, the mobile terminal may include one or more ( Figure 1 Only one is shown) a processor 102 (the processor 102 may include but is not limited to a microprocessor MCU or a programmable logic device FPGA and other processing devices) and a memory 104 for storing data, wherein the mobile terminal may also include a transmission device 106 and an input and output device 108 for communication functions. It will be understood by those skilled in the art that Figure 1The structure shown is only for illustration and does not limit the structure of the mobile terminal. Figure 1 More or fewer components than shown, or with Figure 1 Different configurations shown.

[0044] The memory 104 can be used to store computer programs, such as software programs and modules of application software, such as the computer program corresponding to the device information display method in the embodiment of the present invention. The processor 102 executes various functional applications and data processing by running the computer program stored in the memory 104, that is, implementing the above-mentioned method. The memory 104 may include a high-speed random access memory and may also include a non-volatile memory, such as one or more magnetic storage devices, flash memory, or other non-volatile solid-state memory. In some examples, the memory 104 may further include a memory remotely located relative to the processor 102, and these remote memories can be connected to the mobile terminal via a network. Examples of the above-mentioned networks include but are not limited to the Internet, corporate intranets, local area networks, mobile communication networks, and combinations thereof. The transmission device 106 is used to receive or send data via a network. Specific examples of the above-mentioned network may include a wireless network provided by the mobile terminal's communication provider. In one example, the transmission device 106 includes a network adapter (Network Interface Controller, abbreviated as NIC), which can be connected to other network devices via a base station to communicate with the Internet. In one example, the transmission device 106 may be a radio frequency (RF) module, which is used to communicate with the Internet wirelessly.

[0045] In this embodiment, a method for controlling exhaust emissions running on a mobile terminal, a computer terminal or a similar computing device is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0046] The exhaust emission control method of the embodiment of the present application is applied to a diesel engine after-treatment system, such as Figure 2 As shown, the diesel engine aftertreatment system at least includes an SCR 201, an ASC 202, a control valve 203, and a filter 204 connected in sequence. The outlet of the ASC 202 is connected to the inlet of the filter 204 via a first pipeline 301, and the outlet of the ASC 202 is connected to the outlet of the filter 204 via a second pipeline 302. The control valve 203 is provided on the first pipeline 301 and the second pipeline 302. Figure 3FIG. 1 is a flow chart of a method for controlling exhaust emissions according to an embodiment of the present application. Figure 3 As shown, the method includes the following steps:

[0047] Step S301, obtaining the concentration of ammonia gas introduced into the SCR, where the SCR uses ammonia gas to reduce the concentration of nitrogen oxides in the exhaust gas;

[0048] Specifically, SCR is used in diesel engine aftertreatment applications to reduce the content of nitrogen oxides in engine exhaust. Nitrogen oxides are one of the main harmful components of diesel engine exhaust. The working principle of SCR is to spray a reducing agent into the processor. The reducing agent currently used by SCR is ammonia. Under the catalytic action of the catalyst, at temperature conditions of 290°C to 400°C, the reducing agent ammonia reacts with nitrogen oxides in the exhaust gas to generate nitrogen, while almost no oxidation reaction of ammonia occurs, thereby achieving the purpose of reducing the concentration of nitrogen oxides.

[0049] In an optional solution, the diesel engine after-treatment device further includes a liquid storage tank, which is connected to the SCR. Figure 4 As shown, step S301 can be implemented by the following steps:

[0050] Step S3011, obtaining the urea concentration of the urea aqueous solution introduced into the SCR, the urea aqueous solution being sprayed from the storage tank into the SCR;

[0051] Step S3012: Calculate the concentration of ammonia generated after urea decomposition based on the urea concentration and the chemical formula of urea hydrolysis to obtain the ammonia concentration.

[0052] The aforementioned storage tank can be used to store urea-water solution. In practical applications, the tank can be a urea tank. The aforementioned device may also include numerous components, such as a urea pump, a urea nozzle, a urea injection line, and a urea heating line. For convenient storage and transportation, the vehicle is loaded with a urea (NH2CONH2) aqueous solution (urea or AdBlue, a 32.5% urea-water solution). Urea is preheated in the urea heating line and hydrolyzed to produce ammonia and water. The ammonia reacts with nitrogen oxides (primarily NO and NO2) in the exhaust gas to produce nitrogen and water. The chemical formula for urea hydrolysis allows for accurate calculation of the aforementioned ammonia concentration.

[0053] Step S302, determine whether the above-mentioned ammonia concentration is greater than the predetermined concentration. When the above-mentioned ammonia concentration is greater than the above-mentioned predetermined concentration, control the outlet of the above-mentioned control valve connected to the above-mentioned second pipeline to be closed and control the outlet of the above-mentioned control valve connected to the above-mentioned first pipeline to be opened, so that the above-mentioned exhaust gas is discharged from the above-mentioned first pipeline through the above-mentioned filter, so that excess ammonia is adsorbed by the above-mentioned filter.

[0054] Specifically, when ammonia concentration is too high, ammonia leakage increases. At this point, if a PN measurement device is used to measure the PN value in the exhaust gas, it will identify urea as particulate matter, resulting in excessively high PN emissions. In this case, the control valve is closed, allowing the exhaust gas to exit the ASC and enter the filter behind it. In the filter, ammonia is adsorbed by the surface layer of the porous carrier medium, thereby reducing the risk of PN emissions exceeding the standard. The predetermined concentration can be set according to different operating conditions.

[0055] In actual applications, the control valve may be a three-way valve. Closing the outlet of the control valve connected to the second pipeline means closing the second pipeline between the outlet of the ASC and the outlet of the filter. However, the first pipeline between the outlet of the ASC and the inlet of the filter is open, so the exhaust gas must pass through the filter before it can be discharged.

[0056] In one specific embodiment, the filter comprises a DPF without a precious metal coating and having a high porosity. In this embodiment, the filter only needs to block large particles and does not require a precious metal coating. High porosity allows for better adsorption, while the lack of a precious metal coating reduces costs. Using a DPF without a precious metal coating and having a high porosity allows for a low-cost filter with good particle adsorption.

[0057] In order to increase the service life of the above-mentioned filter, after step S302, the above-mentioned method further includes: when the above-mentioned ammonia concentration is not greater than the above-mentioned predetermined concentration, controlling the outlet of the above-mentioned control valve connected to the above-mentioned second pipeline to be opened and controlling the outlet of the above-mentioned control valve connected to the above-mentioned first pipeline to be closed, so that the above-mentioned exhaust gas is discharged from the above-mentioned second pipeline.

[0058] Opening the outlet of the control valve connected to the second pipeline means opening the second pipeline between the outlet of the ASC and the outlet of the filter, and closing the first pipeline between the outlet of the ASC and the inlet of the filter, so that the exhaust gas does not need to pass through the filter and is directly discharged from the second pipeline. Therefore, when the ammonia concentration in the exhaust gas is not high, that is, when there is no impact on PN emissions, it is directly discharged without passing through the filter, thereby reducing the working time of the filter and increasing the service life of the filter.

[0059] In one option, Figure 5As shown, the diesel engine after-treatment device further includes a DPF205, the outlet of the DPF205 being connected to the inlet of the SCR201, and the method further includes: obtaining the carbon load in the DPF205; determining whether the carbon load is within a predetermined range, and when the carbon load is less than the minimum value of the predetermined range or greater than the maximum value of the predetermined range, controlling the outlet of the control valve connected to the second pipeline to be closed and controlling the outlet of the control valve connected to the first pipeline to be opened, so that the exhaust gas is discharged from the first pipeline through the filter, so that the particles in the exhaust gas are adsorbed by the filter, and when the carbon load is within the predetermined range, controlling the outlet of the control valve connected to the second pipeline to be opened and controlling the outlet of the control valve connected to the first pipeline to be closed, so that the exhaust gas is discharged from the second pipeline. When the carbon load is low, that is, when the DPF has just been regenerated, the carbon load in the DPF is small and the capture efficiency is low, which will cause PN emissions to become higher. At this time, the above-mentioned control valve is closed, and the particles in the exhaust gas come out of the ASC and enter the filter behind it, which can play a role in re-capture, thereby further reducing PN emissions.

[0060] In practice, DPFs currently utilize a wall-flow filter element structure, which forms numerous small, parallel channels along the axial direction. Within adjacent channels within the filter layer, either end is blocked, forcing the exhaust gas through the porous wall to capture particulate matter. DPFs primarily filter and capture particulate matter from engine exhaust through diffusion, deposition, and impaction mechanisms. As exhaust flows through the DPF filter medium, particulate matter is deposited on the porous media of the DPF wall. A layer of carbon deposits adheres to the porous media, and exhaust gas first passes through the carbon layer and then through the porous media. DPF walls with carbon deposits exhibit a capture efficiency exceeding 95%. DPF walls without carbon deposits initially have a capture efficiency of less than 60%. Therefore, DPFs require preconditioning upon initial use to ensure a certain thickness of carbon layer accumulates within the DPF porous media. This layer of carbon deposits gradually improves the DPF's capture efficiency of engine exhaust particulate matter. Therefore, the DPF's carbon loading can be used to determine its capture efficiency. When the carbon loading is below the minimum value within the predetermined range, for example, below 0.5 g / L, the DPF capture efficiency is low and PN emissions are high. The control valve outlet connected to the second pipeline needs to be closed, forcing exhaust gas to pass through the filter before being discharged, thereby reducing PN emissions. As the DPF's operating time increases, the carbon deposit layer on the DPF increases. When the carbon loading exceeds the maximum value within the predetermined range, for example, above 2 g / L, the DPF's filtering effect is affected. The control valve outlet connected to the second pipeline also needs to be closed, forcing exhaust gas to pass through the filter before being discharged, thereby reducing PN emissions. When the carbon load of the DPF is higher than 2g / L, the carbon deposit layer can be removed by DPF regeneration to restore the filtering performance of the DPF. When the carbon deposit layer is too small, the capture effect of the DPF is not good. Therefore, when the carbon load of the DPF is within the above-mentioned predetermined range, the outlet of the control valve connected to the above-mentioned second pipeline is controlled to be open and the outlet of the control valve connected to the above-mentioned first pipeline is controlled to be closed, so that the above-mentioned exhaust gas is discharged from the above-mentioned second pipeline. When the above-mentioned carbon load is less than the minimum value of the above-mentioned predetermined range or greater than the maximum value of the above-mentioned predetermined range, the outlet of the control valve connected to the above-mentioned second pipeline is controlled to be closed and the outlet of the control valve connected to the above-mentioned first pipeline is controlled to be open, so that the above-mentioned exhaust gas is discharged from the above-mentioned first pipeline through the above-mentioned filter, so that the particles in the above-mentioned exhaust gas are adsorbed by the above-mentioned filter.

[0061] In one optional embodiment, the method further includes: obtaining the DPF inlet temperature; determining whether the inlet temperature is greater than a temperature threshold; and if the inlet temperature is greater than the temperature threshold, controlling the outlet of the control valve connected to the second pipeline to close and the outlet of the control valve connected to the first pipeline to open, so that the exhaust gas is discharged from the first pipeline through the filter, thereby allowing particulates in the exhaust gas to be adsorbed by the filter; and if the inlet temperature is not greater than the temperature threshold, controlling the outlet of the control valve connected to the second pipeline to open and the outlet of the control valve connected to the first pipeline to close, so that the exhaust gas is discharged from the second pipeline. When the DPF inlet temperature is too high, the DPF reaches a certain temperature, triggering regeneration, and burning off the carbon deposits on the inner wall of the carrier, which affects the PN capture efficiency and causes higher PN emissions. In this case, closing the intelligent control valve can reduce PN emissions.

[0062] In actual practice, when the DPF inlet temperature exceeds 300°C, the DPF initiates regeneration to remove the carbon deposit layer on the inner wall surface of the carrier. However, if the carbon deposit layer is too small, the DPF's capture effect is poor. The outlet of the control valve connected to the second pipeline is closed, and the outlet of the control valve connected to the first pipeline is opened, allowing the exhaust gas to be discharged from the first pipeline through the filter, so that particulates in the exhaust gas are adsorbed by the filter. Specifically, the DPF inlet temperature can be obtained by a temperature sensor.

[0063] In one option, Figure 6 As shown, the diesel engine aftertreatment device further includes a PN measuring device 206, and the PN measuring device 206 is connected to the outlet of the ASC 202. The method further includes: obtaining the PN value of the exhaust gas tested by the PN measuring device 206, where the PN value is the value of the amount of particulate matter in the exhaust gas; determining whether the PN value is greater than a predetermined value, and when the PN value is greater than the predetermined value, controlling the outlet of the control valve connected to the second pipeline to be closed and controlling the outlet of the control valve connected to the first pipeline to be opened, so that the exhaust gas is discharged from the first pipeline through the filter, so that the particulates in the exhaust gas are adsorbed by the filter; and when the PN value is not greater than the predetermined value, controlling the outlet of the control valve connected to the second pipeline to be open and controlling the outlet of the control valve connected to the first pipeline to be closed, so that the exhaust gas is discharged from the second pipeline.

[0064] Specifically, the PN measurement device can directly measure the PN value, thereby directly judging whether the emission meets the standard. When the PN value is greater than the National VI standard, the outlet of the control valve connected to the second pipeline can be directly closed, so that the exhaust gas is discharged from the first pipeline through the filter, so that the particles in the exhaust gas are adsorbed by the filter, thereby reducing PN emissions. The predetermined value can be 6×10 11 per kilometer.

[0065] In order to ensure that the exhaust gas in the second pipeline is directly discharged outside the pipeline without backflow, an optional solution is as follows: Figure 7 As shown, a one-way valve 207 is provided on the second pipeline, which controls the control valve 203 to open so that the exhaust gas is discharged from the second pipeline 302, including: controlling the control valve 203 and the one-way valve 207 to open so that the exhaust gas is discharged from the second pipeline 302.

[0066] In a specific embodiment, Figure 8 As shown, the diesel engine after-treatment device also includes DOC208, and the outlet of the DOC208 is connected to the inlet of the DPF205. DOC is a precious metal catalyst (such as Pt, etc.) coated on a honeycomb ceramic carrier. Its purpose is to reduce the chemical reaction activation energy of hydrocarbons, carbon monoxide and soluble organic matter in the engine exhaust, so that these substances can undergo oxidation reaction with oxygen in the exhaust at a lower temperature and eventually be converted into carbon dioxide and water. The oxidative catalytic converter does not require a regeneration system and a control device, has the characteristics of simple structure and good reliability, and has been applied to modern small engines to a certain extent. Emission after-treatment catalysts, including DOC, DPF, SCR and ASR, have become one of the necessary configurations of diesel engines.

[0067] Through the above embodiment, the method determines whether the ammonia concentration entering the SCR is greater than a predetermined concentration, and when the ammonia concentration is greater than the predetermined concentration, closes the outlet of the intelligent control valve connected to the above-mentioned second pipeline, so that the exhaust gas passes from the outlet of the ASC to the inlet of the filter through the first pipeline, so that the excess ammonia is adsorbed by the filter, thereby achieving the purpose of reducing PN emissions, thereby solving the problem of PN emissions easily exceeding the standard in the prior art.

[0068] In order to enable those skilled in the art to more clearly understand the technical solution of the present application, the implementation process of the exhaust emission control method of the present application will be described in detail below with reference to specific embodiments.

[0069] This embodiment relates to a specific exhaust emission control method, which is applied to a diesel engine after-treatment system, such as Figure 8As shown, the diesel engine aftertreatment system includes a DOC208, a DPF205, an SCR201, an ASC202, a control valve 203, and a filter 204 connected in sequence. The outlet of the ASC202 is connected to the inlet of the filter 204 via a first pipeline 301, and the outlet of the ASC202 is connected to the outlet of the filter 204 via a second pipeline 302. The control valve 203 is provided on the first pipeline 301 and on the second pipeline 302. A one-way valve 207 is provided on the second pipeline to control the opening of the control valve 203 so that the exhaust gas is discharged from the second pipeline 302. The exhaust gas emission control method is as follows: Figure 9 As shown, the following steps are included:

[0070] Step S1: Obtaining the ammonia concentration of the SCR. Specifically, obtaining the ammonia concentration of the SCR includes: obtaining the urea concentration of the urea aqueous solution introduced into the SCR, the urea aqueous solution being sprayed into the SCR from a reservoir; and calculating the concentration of ammonia generated by urea decomposition based on the urea concentration and the chemical formula for urea hydrolysis, thereby obtaining the ammonia concentration. The reservoir may be a urea tank. Urea is preheated in a urea heating line to undergo hydrolysis, generating ammonia and water. The ammonia reacts with nitrogen oxides (primarily NO and NO2) in the exhaust gas to generate nitrogen and water through a reduction reaction. The ammonia concentration can be accurately calculated using the chemical formula for urea hydrolysis.

[0071] Step S2: determining whether the ammonia concentration is greater than a predetermined concentration;

[0072] Step S3: When the ammonia concentration is greater than the predetermined concentration, the outlet of the control valve connected to the second pipeline is controlled to be closed, and the outlet of the control valve connected to the first pipeline is controlled to be opened, so that the exhaust gas is discharged from the first pipeline through the filter, so that excess ammonia is adsorbed by the filter; when the ammonia concentration is too high, ammonia leakage will become larger. At this time, if a PN measuring device is used to test the PN value in the exhaust gas, the PN measuring device will identify urea as particles, resulting in the measured PN emissions being too high. At this time, the control valve is closed, allowing the exhaust gas to exit the ASC and enter the filter behind it. In the filter, the adsorption effect of ammonia on the surface of the carrier porous medium is utilized to reduce the risk of PN emissions exceeding the standard.

[0073] Step S4: When the ammonia concentration is not greater than the predetermined concentration, the outlet of the control valve connected to the second pipeline is controlled to be open and the outlet of the control valve connected to the first pipeline is controlled to be closed, so that the exhaust gas is discharged from the second pipeline; when the ammonia concentration in the exhaust gas is not high, that is, when it has no effect on PN emissions, it is discharged directly without passing through the filter, thereby reducing the working time of the filter and increasing the service life of the filter.

[0074] Step S5: Obtaining the carbon load in the DPF;

[0075] Step S6: determining whether the carbon loading is within a predetermined range;

[0076] Step S7: When the carbon loading is less than the minimum value of the predetermined range or greater than the maximum value of the predetermined range, the outlet of the control valve connected to the second pipeline is controlled to be closed, and the outlet of the control valve connected to the first pipeline is controlled to be opened, so that the exhaust gas is discharged from the first pipeline through the filter, so that particulates in the exhaust gas are adsorbed by the filter. The DPF's capture efficiency can be determined by the carbon loading of the DPF. When the carbon loading is less than the minimum value of the predetermined range, such as less than 0.5 g / L, the DPF capture efficiency is low and PN emissions are high, requiring the outlet of the control valve connected to the second pipeline to be closed. As the DPF operates for a longer time, the carbon deposit layer on the DPF increases. When the carbon loading is greater than the maximum value of the predetermined range, such as greater than 2 g / L, the DPF's filtering effect is affected, requiring the outlet of the control valve connected to the second pipeline to be closed, requiring the exhaust gas to pass through the filter before being discharged, thereby reducing PN emissions.

[0077] Step S8: When the carbon loading is within the predetermined range, the outlet of the control valve connected to the second pipeline is controlled to be open and the outlet of the control valve connected to the first pipeline is controlled to be closed, so that the exhaust gas is discharged from the second pipeline.

[0078] Step S9: obtaining the inlet temperature of the DPF;

[0079] Step S10: determining whether the inlet temperature is greater than a temperature threshold;

[0080] Step S11: When the inlet temperature is greater than the temperature threshold, the outlet of the control valve connected to the second pipeline is controlled to be closed and the outlet of the control valve connected to the first pipeline is controlled to be opened, so that the exhaust gas is discharged from the first pipeline through the filter, so that the particles in the exhaust gas are adsorbed by the filter; as the working time increases, more and more carbon deposits are deposited on the DPF. When the carbon load is higher than the maximum value of the predetermined range, such as higher than 2g / L, it affects the filtering effect of the DPF, and the outlet of the control valve connected to the second pipeline needs to be closed.

[0081] Step S12: When the inlet temperature is not greater than the temperature threshold, controlling the outlet of the control valve connected to the second pipeline to open and controlling the outlet of the control valve connected to the first pipeline to close, so that the exhaust gas is discharged from the second pipeline;

[0082] Step S13: obtaining the PN value of the exhaust gas measured by the PN measuring device;

[0083] Step S14: Determine whether the PN value is greater than a predetermined value;

[0084] Step S15: When the PN value is greater than the predetermined value, the outlet of the control valve connected to the second pipeline is controlled to be closed and the outlet of the control valve connected to the first pipeline is controlled to be opened, so that the exhaust gas is discharged from the first pipeline through the filter, so that the particles in the exhaust gas are adsorbed by the filter; the PN measuring device can directly measure the PN value, so as to directly determine whether the emission meets the standard. When the PN value is greater than the National VI standard, the outlet of the control valve connected to the second pipeline can be directly closed, so that the exhaust gas is discharged from the first pipeline through the filter, so that the particles in the exhaust gas are adsorbed by the filter, thereby reducing PN emissions.

[0085] Step S16: When the PN value is not greater than the predetermined value, the outlet of the control valve connected to the second pipeline is controlled to be open and the outlet of the control valve connected to the first pipeline is controlled to be closed, so that the exhaust gas is discharged from the second pipeline.

[0086] In practical applications, the control valve may be a three-way valve. Closing the outlet of the control valve connected to the second pipeline means closing the second pipeline between the outlet of the ASC and the outlet of the filter. However, the first pipeline between the outlet of the ASC and the inlet of the filter remains open, so exhaust gas must pass through the filter before being discharged. Opening the outlet of the control valve connected to the second pipeline means opening the second pipeline between the outlet of the ASC and the outlet of the filter and closing the first pipeline between the outlet of the ASC and the inlet of the filter, so that exhaust gas does not need to pass through the filter and is discharged directly from the second pipeline.

[0087] It should be noted that the steps shown in the flowcharts of the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and that, although a logical order is shown in the flowcharts, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0088] The present application also provides an exhaust emission control device for use in a diesel engine after-treatment system. Figure 2As shown, the diesel engine aftertreatment system at least includes an SCR201, an ASC202, a control valve 203 and a filter 204 connected in sequence. The outlet of the ASC202 is connected to the inlet of the filter 204 via a first pipeline 301, and the outlet of the ASC202 is connected to the outlet of the filter 204 via a second pipeline 302. The control valve 203 is arranged on the first pipeline 301 and on the second pipeline 302. It should be noted that the exhaust emission control device of the embodiment of the present application can be used to execute the exhaust emission control method provided in the embodiment of the present application. The device is used to implement the above-mentioned embodiments and preferred embodiments, and the details that have been explained will not be repeated. As used below, the term "module" can implement a combination of software and / or hardware that implements a predetermined function. Although the device described in the following embodiments is preferably implemented in software, implementation in hardware, or a combination of software and hardware, is also possible and conceivable.

[0089] The following is an introduction to the exhaust emission control device provided in the embodiments of the present application.

[0090] Figure 10 Schematic diagram of the exhaust emission control device according to an embodiment of the present application. Figure 10 As shown, the device includes: a first acquisition unit 10 and a first control unit 20, wherein:

[0091] The first acquisition unit 10 is used to acquire the concentration of ammonia gas introduced into the SCR. The SCR uses ammonia gas to reduce the concentration of nitrogen oxides in the exhaust gas.

[0092] Specifically, SCR is used in diesel engine aftertreatment applications to reduce the content of nitrogen oxides in engine exhaust. Nitrogen oxides are one of the main harmful components of diesel engine exhaust. The working principle of SCR is to spray a reducing agent into the processor. The reducing agent currently used by SCR is ammonia. Under the catalytic action of the catalyst, at temperature conditions of 290°C to 400°C, the reducing agent ammonia reacts with nitrogen oxides in the exhaust gas to generate nitrogen, while almost no oxidation reaction of ammonia occurs, thereby achieving the purpose of reducing the concentration of nitrogen oxides.

[0093] In an optional solution, the diesel engine after-treatment device further includes a liquid storage tank, which is connected to the SCR. Figure 4 As shown, the first acquisition unit includes an acquisition module and a calculation module, wherein the acquisition module is used to obtain the urea concentration of the urea aqueous solution introduced into the SCR, and the urea aqueous solution is sprayed into the SCR from the storage tank; the calculation module is used to calculate the concentration of ammonia generated after urea decomposition based on the urea concentration and the chemical formula of urea hydrolysis, so as to obtain the ammonia concentration.

[0094] The aforementioned storage tank can be used to store urea-water solution. In practical applications, the tank can be a urea tank. The aforementioned device may also include numerous components, such as a urea pump, a urea nozzle, a urea injection line, and a urea heating line. For convenient storage and transportation, the vehicle is loaded with a urea (NH2CONH2) aqueous solution (urea or AdBlue, a 32.5% urea-water solution). Urea is preheated in the urea heating line and hydrolyzed to produce ammonia and water. The ammonia reacts with nitrogen oxides (primarily NO and NO2) in the exhaust gas to produce nitrogen and water. The chemical formula for urea hydrolysis allows for accurate calculation of the aforementioned ammonia concentration.

[0095] The first control unit 20 is used to determine whether the ammonia concentration is greater than a predetermined concentration. When the ammonia concentration is greater than the predetermined concentration, the outlet of the control valve connected to the second pipeline is controlled to be closed and the outlet of the control valve connected to the first pipeline is controlled to be opened, so that the exhaust gas is discharged from the first pipeline through the filter, so that excess ammonia is adsorbed by the filter.

[0096] Specifically, when the ammonia concentration is too high, ammonia leakage will increase. At this time, if a PN measuring device is used to test the PN value in the exhaust gas, the PN measuring device will identify urea as particles, resulting in the measured PN emissions being too high. At this time, the control valve is closed, allowing the exhaust gas to exit the above-mentioned ASC and enter the above-mentioned filter behind it. In the filter, the adsorption effect of ammonia on the surface of the carrier porous medium is utilized to reduce the risk of PN emissions exceeding the standard.

[0097] In actual applications, the control valve may be a three-way valve. Closing the outlet of the control valve connected to the second pipeline means closing the second pipeline between the outlet of the ASC and the outlet of the filter. However, the first pipeline between the outlet of the ASC and the inlet of the filter is open, so the exhaust gas must pass through the filter before it can be discharged.

[0098] In one specific embodiment, the filter comprises a DPF without a precious metal coating and having a high porosity. In this embodiment, the filter only needs to block large particles and does not require a precious metal coating. High porosity allows for better adsorption, while the lack of a precious metal coating reduces costs. Using a DPF without a precious metal coating and having a high porosity allows for a low-cost filter with good particle adsorption.

[0099] In order to increase the service life of the above-mentioned filter, the above-mentioned device also includes a second control unit, which is used to control the outlet of the above-mentioned control valve connected to the above-mentioned second pipeline to be opened and the outlet of the above-mentioned control valve connected to the above-mentioned first pipeline to be closed when the above-mentioned ammonia concentration is not greater than the above-mentioned predetermined concentration, so that the above-mentioned exhaust gas is discharged from the above-mentioned second pipeline.

[0100] Opening the outlet of the control valve connected to the second pipeline means opening the second pipeline between the outlet of the ASC and the outlet of the filter, and closing the first pipeline between the outlet of the ASC and the inlet of the filter, so that the exhaust gas does not need to pass through the filter and is directly discharged from the second pipeline. Therefore, when the ammonia concentration in the exhaust gas is not high, that is, when there is no impact on PN emissions, it is directly discharged without passing through the filter, thereby reducing the working time of the filter and increasing the service life of the filter.

[0101] In one option, Figure 5 As shown, the diesel engine after-treatment device further includes a DPF205, the outlet of the DPF205 being connected to the inlet of the SCR201, and the device further includes a second acquisition unit and a third control unit, wherein the second acquisition unit is used to acquire the carbon load in the DPF205; the third control unit is used to determine whether the carbon load is within a predetermined range, and when the carbon load is less than the minimum value of the predetermined range or greater than the maximum value of the predetermined range, the outlet of the control valve connected to the second pipeline is controlled to be closed and the outlet of the control valve connected to the first pipeline is controlled to be opened, so that the exhaust gas is discharged from the first pipeline through the filter, so that the particles in the exhaust gas are adsorbed by the filter, and when the carbon load is within the predetermined range, the outlet of the control valve connected to the second pipeline is controlled to be opened and the outlet of the control valve connected to the first pipeline is controlled to be closed, so that the exhaust gas is discharged from the second pipeline. When the carbon load is low, that is, when the DPF has just been regenerated, the carbon load in the DPF is small and the capture efficiency is low, which will cause PN emissions to become higher. At this time, the above-mentioned control valve is closed, and the particles in the exhaust gas come out of the ASC and enter the filter behind it, which can play a role in re-capture, thereby further reducing PN emissions.

[0102] In practice, DPFs currently utilize a wall-flow filter element structure, which forms numerous small, parallel channels along the axial direction. Within adjacent channels within the filter layer, either end is blocked, forcing the exhaust gas through the porous wall to capture particulate matter. DPFs primarily filter and capture particulate matter from engine exhaust through diffusion, deposition, and impaction mechanisms. As exhaust flows through the DPF filter medium, particulate matter is deposited on the porous media of the DPF wall. A layer of carbon deposits adheres to the porous media, and exhaust gas first passes through the carbon layer and then through the porous media. DPF walls with carbon deposits exhibit a capture efficiency exceeding 95%. DPF walls without carbon deposits initially have a capture efficiency of less than 60%. Therefore, DPFs require preconditioning upon initial use to ensure a certain thickness of carbon layer accumulates within the DPF porous media. This layer of carbon deposits gradually improves the DPF's capture efficiency of engine exhaust particulate matter. Therefore, the DPF's carbon loading can be used to determine its capture efficiency. When the carbon loading is below the minimum value within the predetermined range, for example, below 0.5 g / L, the DPF capture efficiency is low and PN emissions are high. The control valve outlet connected to the second pipeline needs to be closed, forcing exhaust gas to pass through the filter before being discharged, thereby reducing PN emissions. As the DPF's operating time increases, the carbon deposit layer on the DPF increases. When the carbon loading exceeds the maximum value within the predetermined range, for example, above 2 g / L, the DPF's filtering effect is affected. The control valve outlet connected to the second pipeline also needs to be closed, forcing exhaust gas to pass through the filter before being discharged, thereby reducing PN emissions. When the carbon load of the DPF is higher than 2g / L, the carbon deposit layer can be removed by DPF regeneration to restore the filtering performance of the DPF. When the carbon deposit layer is too small, the capture effect of the DPF is not good. Therefore, when the carbon load of the DPF is within the above-mentioned predetermined range, the outlet of the control valve connected to the above-mentioned second pipeline is controlled to be open and the outlet of the control valve connected to the above-mentioned first pipeline is controlled to be closed, so that the above-mentioned exhaust gas is discharged from the above-mentioned second pipeline. When the above-mentioned carbon load is less than the minimum value of the above-mentioned predetermined range or greater than the maximum value of the above-mentioned predetermined range, the outlet of the control valve connected to the above-mentioned second pipeline is controlled to be closed and the outlet of the control valve connected to the above-mentioned first pipeline is controlled to be open, so that the above-mentioned exhaust gas is discharged from the above-mentioned first pipeline through the above-mentioned filter, so that the particles in the above-mentioned exhaust gas are adsorbed by the above-mentioned filter.

[0103] In one optional embodiment, the device further includes a third acquisition unit and a fourth control unit, wherein the third acquisition unit is configured to acquire the DPF inlet temperature; and the fourth control unit is configured to determine whether the inlet temperature is greater than a temperature threshold. If the inlet temperature is greater than the temperature threshold, the control valve is controlled to close the outlet of the second pipeline and to open the outlet of the first pipeline, allowing the exhaust gas to be discharged from the first pipeline through the filter, thereby allowing particulates in the exhaust gas to be adsorbed by the filter. If the inlet temperature is not greater than the temperature threshold, the control valve is controlled to open the outlet of the second pipeline and close the outlet of the first pipeline, allowing the exhaust gas to be discharged from the second pipeline. When the DPF inlet temperature is too high, the DPF reaches a certain temperature, triggering regeneration, burning off the carbon deposits on the inner wall of the carrier, affecting the PN capture efficiency and resulting in higher PN emissions. Closing the intelligent control valve at this time can reduce PN emissions.

[0104] In actual practice, when the DPF inlet temperature exceeds 300°C, the DPF initiates regeneration to remove the carbon deposit layer on the inner wall surface of the carrier. However, if the carbon deposit layer is too small, the DPF's capture effect is poor. The outlet of the control valve connected to the second pipeline is closed, and the outlet of the control valve connected to the first pipeline is opened, allowing the exhaust gas to be discharged from the first pipeline through the filter, so that particulates in the exhaust gas are adsorbed by the filter. Specifically, the DPF inlet temperature can be obtained by a temperature sensor.

[0105] In one option, Figure 6 As shown, the diesel engine aftertreatment device further includes a PN measuring device 206, which is connected to the outlet of the ASC 202. The device further includes a fourth acquisition unit and a fifth control unit, wherein the fourth acquisition unit is used to obtain the PN value of the exhaust gas tested by the PN measuring device 206, and the PN value is the value of the number of particulate matter in the exhaust gas; the fifth control unit is used to determine whether the PN value is greater than a predetermined value. When the PN value is greater than the predetermined value, the outlet of the control valve connected to the second pipeline is controlled to be closed and the outlet of the control valve connected to the first pipeline is controlled to be opened, so that the exhaust gas is discharged from the first pipeline through the filter, so that the particulates in the exhaust gas are adsorbed by the filter. When the PN value is not greater than the predetermined value, the outlet of the control valve connected to the second pipeline is controlled to be opened and the outlet of the control valve connected to the first pipeline is controlled to be closed, so that the exhaust gas is discharged from the second pipeline.

[0106] Specifically, the PN measuring device can directly measure the PN value, thereby directly judging whether the emissions meet the standards. When the PN value is greater than the National VI standard, the outlet of the control valve connected to the above-mentioned second pipeline can be directly closed, so that the above-mentioned exhaust gas is discharged from the above-mentioned first pipeline through the above-mentioned filter, so that the particles in the above-mentioned exhaust gas are adsorbed by the above-mentioned filter, thereby reducing PN emissions.

[0107] In order to ensure that the exhaust gas in the second pipeline is directly discharged outside the pipeline without backflow, an optional solution is as follows: Figure 7 As shown, a one-way valve 207 is provided on the second pipeline to control the opening of the control valve 203 so that the exhaust gas is discharged from the second pipeline 302. The device includes a sixth control unit, which is used to control the opening of the control valve 203 and the one-way valve 207 so that the exhaust gas is discharged from the second pipeline 302.

[0108] In a specific embodiment, Figure 8 As shown, the diesel engine after-treatment device also includes DOC208, and the outlet of the DOC208 is connected to the inlet of the DPF205. DOC is a precious metal catalyst (such as Pt, etc.) coated on a honeycomb ceramic carrier. Its purpose is to reduce the chemical reaction activation energy of hydrocarbons, carbon monoxide and soluble organic matter in the engine exhaust, so that these substances can undergo oxidation reaction with oxygen in the exhaust at a lower temperature and eventually be converted into carbon dioxide and water. The oxidative catalytic converter does not require a regeneration system and a control device, has the characteristics of simple structure and good reliability, and has been applied to modern small engines to a certain extent. Emission after-treatment catalysts, including DOC, DPF, SCR and ASR, have become one of the necessary configurations of diesel engines.

[0109] Through the above embodiment, the above device determines whether the ammonia concentration entering the SCR is greater than a predetermined concentration, and when the ammonia concentration is greater than the predetermined concentration, closes the outlet of the intelligent control valve connected to the above second pipeline, so that the exhaust gas passes from the outlet of the ASC to the inlet of the filter through the first pipeline, so that the excess ammonia is adsorbed by the filter, thereby achieving the purpose of reducing PN emissions, thereby solving the problem of PN emissions easily exceeding the standard in the prior art.

[0110] The exhaust emission control device includes a processor and a memory. The first acquisition unit and the first control unit are stored in the memory as program units. The processor executes the program units stored in the memory to implement the corresponding functions. The modules are all located in the same processor; alternatively, the modules can be located in different processors in any combination.

[0111] The processor includes a core, which retrieves the corresponding program unit from the memory. One or more cores can be provided, and the problem of PN emissions exceeding the standard in the prior art can be solved by adjusting the core parameters.

[0112] The memory may include non-permanent memory in a computer-readable medium, random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM, and the memory includes at least one memory chip.

[0113] According to another aspect of the present application, a diesel engine aftertreatment system is provided, comprising at least a controller, an SCR, an ASC, a control valve and a filter connected in sequence, wherein the outlet of the ASC is connected to the inlet of the filter via a first pipeline, the outlet of the ASC is connected to the outlet of the filter via a second pipeline, the control valve is arranged on the first pipeline and on the second pipeline, and the controller is used to execute any one of the above-mentioned exhaust emission control methods.

[0114] The diesel engine aftertreatment system includes a controller configured to execute any of the aforementioned exhaust emission control methods. This method determines whether the ammonia concentration entering the SCR is greater than a predetermined concentration. If the ammonia concentration is greater than the predetermined concentration, the intelligent control valve's outlet connected to the second pipeline is closed, allowing exhaust gas to pass from the outlet of the ASC through the first pipeline to the inlet of the filter. Excess ammonia is adsorbed by the filter, thereby reducing PN emissions and addressing the issue of PN emissions easily exceeding standards in the prior art.

[0115] In one alternative, the filter comprises a DPF without a precious metal coating and having a high porosity. In this embodiment, the filter only needs to block large particles and does not require a precious metal coating. High porosity allows for better adsorption, while the lack of a precious metal coating reduces costs. Using a DPF without a precious metal coating and having a high porosity allows for a low-cost filter with good particle adsorption.

[0116] An embodiment of the present invention provides a computer-readable storage medium, which includes a stored program. When the program is executed, the device where the computer-readable storage medium is located is controlled to execute the exhaust emission control method.

[0117] Specifically, the exhaust emission control methods include:

[0118] Step S301, obtaining the concentration of ammonia gas introduced into the SCR, where the SCR uses ammonia gas to reduce the concentration of nitrogen oxides in the exhaust gas;

[0119] Specifically, SCR is used in diesel engine aftertreatment applications to reduce the content of nitrogen oxides in engine exhaust. Nitrogen oxides are one of the main harmful components of diesel engine exhaust. The working principle of SCR is to spray a reducing agent into the processor. The reducing agent currently used by SCR is ammonia. Under the catalytic action of the catalyst, at temperature conditions of 290°C to 400°C, the reducing agent ammonia reacts with nitrogen oxides in the exhaust gas to generate nitrogen, while almost no oxidation reaction of ammonia occurs, thereby achieving the purpose of reducing the concentration of nitrogen oxides.

[0120] Step S302, determine whether the above-mentioned ammonia concentration is greater than the predetermined concentration. When the above-mentioned ammonia concentration is greater than the above-mentioned predetermined concentration, control the outlet of the above-mentioned control valve connected to the above-mentioned second pipeline to be closed and control the outlet of the above-mentioned control valve connected to the above-mentioned first pipeline to be opened, so that the above-mentioned exhaust gas is discharged from the above-mentioned first pipeline through the above-mentioned filter, so that excess ammonia is adsorbed by the above-mentioned filter.

[0121] Specifically, when the ammonia concentration is too high, ammonia leakage will increase. At this time, if a PN measuring device is used to test the PN value in the exhaust gas, the PN measuring device will identify urea as particles, resulting in the measured PN emissions being too high. At this time, the control valve is closed, allowing the exhaust gas to exit the above-mentioned ASC and enter the above-mentioned filter behind it. In the filter, the adsorption effect of ammonia on the surface of the carrier porous medium is utilized to reduce the risk of PN emissions exceeding the standard.

[0122] Optionally, after determining whether the above-mentioned ammonia concentration is greater than the predetermined concentration, the above-mentioned method also includes: when the above-mentioned ammonia concentration is not greater than the above-mentioned predetermined concentration, controlling the outlet of the above-mentioned control valve connected to the above-mentioned second pipeline to be opened and controlling the outlet of the above-mentioned control valve connected to the above-mentioned first pipeline to be closed, so that the above-mentioned exhaust gas is discharged from the above-mentioned second pipeline.

[0123] Optionally, the diesel engine after-treatment device further includes a DPF, and the outlet of the DPF is connected to the inlet of the SCR. The method further includes: obtaining the carbon load in the DPF; determining whether the carbon load is within a predetermined range, and when the carbon load is less than the minimum value of the predetermined range or greater than the maximum value of the predetermined range, controlling the outlet of the control valve connected to the second pipeline to be closed and controlling the outlet of the control valve connected to the first pipeline to be opened, so that the exhaust gas is discharged from the first pipeline through the filter, so that the particles in the exhaust gas are adsorbed by the filter, and when the carbon load is within the predetermined range, controlling the outlet of the control valve connected to the second pipeline to be opened and controlling the outlet of the control valve connected to the first pipeline to be closed, so that the exhaust gas is discharged from the second pipeline.

[0124] Optionally, the method further includes: obtaining the inlet temperature of the DPF; determining whether the inlet temperature is greater than a temperature threshold; if the inlet temperature is greater than the temperature threshold, controlling the outlet of the control valve connected to the second pipeline to be closed and controlling the outlet of the control valve connected to the first pipeline to be opened, so that the exhaust gas is discharged from the first pipeline through the filter, so that the particles in the exhaust gas are adsorbed by the filter; if the inlet temperature is not greater than the temperature threshold, controlling the outlet of the control valve connected to the second pipeline to be opened and controlling the outlet of the control valve connected to the first pipeline to be closed, so that the exhaust gas is discharged from the second pipeline.

[0125] Optionally, the diesel engine aftertreatment device further includes a PN measuring device, which is connected to the outlet of the ASC. The method further includes: obtaining the PN value of the exhaust gas tested by the PN measuring device, where the PN value is the value of the amount of particulate matter in the exhaust gas; determining whether the PN value is greater than a predetermined value, and if the PN value is greater than the predetermined value, controlling the outlet of the control valve connected to the second pipeline to be closed and controlling the outlet of the control valve connected to the first pipeline to be opened, so that the exhaust gas is discharged from the first pipeline through the filter, so that the particles in the exhaust gas are adsorbed by the filter; and if the PN value is not greater than the predetermined value, controlling the outlet of the control valve connected to the second pipeline to be open and controlling the outlet of the control valve connected to the first pipeline to be closed, so that the exhaust gas is discharged from the second pipeline.

[0126] Optionally, the diesel engine after-treatment device further includes a liquid storage tank connected to the SCR. The steps of obtaining the ammonia concentration introduced into the SCR include: obtaining the urea concentration of a urea aqueous solution introduced into the SCR, wherein the urea aqueous solution is sprayed from the liquid storage tank into the SCR; and calculating the concentration of ammonia generated after decomposition of urea based on the urea concentration and a chemical formula for urea hydrolysis to obtain the ammonia concentration.

[0127] Optionally, a one-way valve is provided on the second pipeline, which controls the outlet of the control valve connected to the second pipeline to be opened and controls the outlet of the control valve connected to the first pipeline to be closed, so that the exhaust gas is discharged from the second pipeline, including: controlling the control valve and the one-way valve to be opened, so that the exhaust gas is discharged from the second pipeline.

[0128] An embodiment of the present invention provides a processor, which is used to run a program, wherein the exhaust emission control method is executed when the program is run.

[0129] Specifically, the exhaust emission control methods include:

[0130] Step S301, obtaining the concentration of ammonia gas introduced into the SCR, where the SCR uses ammonia gas to reduce the concentration of nitrogen oxides in the exhaust gas;

[0131] Specifically, SCR is used in diesel engine aftertreatment applications to reduce the content of nitrogen oxides in engine exhaust. Nitrogen oxides are one of the main harmful components of diesel engine exhaust. The working principle of SCR is to spray a reducing agent into the processor. The reducing agent currently used by SCR is ammonia. Under the catalytic action of the catalyst, at temperature conditions of 290°C to 400°C, the reducing agent ammonia reacts with nitrogen oxides in the exhaust gas to generate nitrogen, while almost no oxidation reaction of ammonia occurs, thereby achieving the purpose of reducing the concentration of nitrogen oxides.

[0132] Step S302, determine whether the above-mentioned ammonia concentration is greater than the predetermined concentration. When the above-mentioned ammonia concentration is greater than the above-mentioned predetermined concentration, control the outlet of the above-mentioned control valve connected to the above-mentioned second pipeline to be closed and control the outlet of the above-mentioned control valve connected to the above-mentioned first pipeline to be opened, so that the above-mentioned exhaust gas is discharged from the above-mentioned first pipeline through the above-mentioned filter, so that excess ammonia is adsorbed by the above-mentioned filter.

[0133] Specifically, when the ammonia concentration is too high, ammonia leakage will increase. At this time, if a PN measuring device is used to test the PN value in the exhaust gas, the PN measuring device will identify urea as particles, resulting in the measured PN emissions being too high. At this time, the control valve is closed, allowing the exhaust gas to exit the above-mentioned ASC and enter the above-mentioned filter behind it. In the filter, the adsorption effect of ammonia on the surface of the carrier porous medium is utilized to reduce the risk of PN emissions exceeding the standard.

[0134] Optionally, after determining whether the above-mentioned ammonia concentration is greater than the predetermined concentration, the above-mentioned method also includes: when the above-mentioned ammonia concentration is not greater than the above-mentioned predetermined concentration, controlling the outlet of the above-mentioned control valve connected to the above-mentioned second pipeline to be opened and controlling the outlet of the above-mentioned control valve connected to the above-mentioned first pipeline to be closed, so that the above-mentioned exhaust gas is discharged from the above-mentioned second pipeline.

[0135] Optionally, the diesel engine after-treatment device further includes a DPF, and the outlet of the DPF is connected to the inlet of the SCR. The method further includes: obtaining the carbon load in the DPF; determining whether the carbon load is within a predetermined range, and when the carbon load is less than the minimum value of the predetermined range or greater than the maximum value of the predetermined range, controlling the outlet of the control valve connected to the second pipeline to be closed and controlling the outlet of the control valve connected to the first pipeline to be opened, so that the exhaust gas is discharged from the first pipeline through the filter, so that the particles in the exhaust gas are adsorbed by the filter, and when the carbon load is within the predetermined range, controlling the outlet of the control valve connected to the second pipeline to be opened and controlling the outlet of the control valve connected to the first pipeline to be closed, so that the exhaust gas is discharged from the second pipeline.

[0136] Optionally, the method further includes: obtaining the inlet temperature of the DPF; determining whether the inlet temperature is greater than a temperature threshold; if the inlet temperature is greater than the temperature threshold, controlling the outlet of the control valve connected to the second pipeline to be closed and controlling the outlet of the control valve connected to the first pipeline to be opened, so that the exhaust gas is discharged from the first pipeline through the filter, so that the particles in the exhaust gas are adsorbed by the filter; if the inlet temperature is not greater than the temperature threshold, controlling the outlet of the control valve connected to the second pipeline to be opened and controlling the outlet of the control valve connected to the first pipeline to be closed, so that the exhaust gas is discharged from the second pipeline.

[0137] Optionally, the diesel engine aftertreatment device further includes a PN measuring device, which is connected to the outlet of the ASC. The method further includes: obtaining the PN value of the exhaust gas tested by the PN measuring device, where the PN value is the value of the amount of particulate matter in the exhaust gas; determining whether the PN value is greater than a predetermined value, and if the PN value is greater than the predetermined value, controlling the outlet of the control valve connected to the second pipeline to be closed and controlling the outlet of the control valve connected to the first pipeline to be opened, so that the exhaust gas is discharged from the first pipeline through the filter, so that the particles in the exhaust gas are adsorbed by the filter; and if the PN value is not greater than the predetermined value, controlling the outlet of the control valve connected to the second pipeline to be open and controlling the outlet of the control valve connected to the first pipeline to be closed, so that the exhaust gas is discharged from the second pipeline.

[0138] Optionally, the diesel engine after-treatment device further includes a liquid storage tank connected to the SCR. The steps of obtaining the ammonia concentration introduced into the SCR include: obtaining the urea concentration of a urea aqueous solution introduced into the SCR, wherein the urea aqueous solution is sprayed from the liquid storage tank into the SCR; and calculating the concentration of ammonia generated after decomposition of urea based on the urea concentration and a chemical formula for urea hydrolysis to obtain the ammonia concentration.

[0139] Optionally, a one-way valve is provided on the second pipeline, which controls the outlet of the control valve connected to the second pipeline to be opened and controls the outlet of the control valve connected to the first pipeline to be closed, so that the exhaust gas is discharged from the second pipeline, including: controlling the control valve and the one-way valve to be opened, so that the exhaust gas is discharged from the second pipeline.

[0140] An embodiment of the present invention provides a device, comprising a processor, a memory, and a program stored in the memory and executable on the processor. When the processor executes the program, at least the following steps are performed:

[0141] Step S301, obtaining the concentration of ammonia gas introduced into the SCR, where the SCR uses ammonia gas to reduce the concentration of nitrogen oxides in the exhaust gas;

[0142] Step S302, determine whether the above-mentioned ammonia concentration is greater than the predetermined concentration. When the above-mentioned ammonia concentration is greater than the above-mentioned predetermined concentration, control the outlet of the above-mentioned control valve connected to the above-mentioned second pipeline to be closed and control the outlet of the above-mentioned control valve connected to the above-mentioned first pipeline to be opened, so that the above-mentioned exhaust gas is discharged from the above-mentioned first pipeline through the above-mentioned filter, so that excess ammonia is adsorbed by the above-mentioned filter.

[0143] Optionally, after determining whether the above-mentioned ammonia concentration is greater than the predetermined concentration, the above-mentioned method also includes: when the above-mentioned ammonia concentration is not greater than the above-mentioned predetermined concentration, controlling the outlet of the above-mentioned control valve connected to the above-mentioned second pipeline to be opened and controlling the outlet of the above-mentioned control valve connected to the above-mentioned first pipeline to be closed, so that the above-mentioned exhaust gas is discharged from the above-mentioned second pipeline.

[0144] Optionally, the diesel engine after-treatment device further includes a DPF, and the outlet of the DPF is connected to the inlet of the SCR. The method further includes: obtaining the carbon load in the DPF; determining whether the carbon load is within a predetermined range, and when the carbon load is less than the minimum value of the predetermined range or greater than the maximum value of the predetermined range, controlling the outlet of the control valve connected to the second pipeline to be closed and controlling the outlet of the control valve connected to the first pipeline to be opened, so that the exhaust gas is discharged from the first pipeline through the filter, so that the particles in the exhaust gas are adsorbed by the filter, and when the carbon load is within the predetermined range, controlling the outlet of the control valve connected to the second pipeline to be opened and controlling the outlet of the control valve connected to the first pipeline to be closed, so that the exhaust gas is discharged from the second pipeline.

[0145] Optionally, the method further includes: obtaining the inlet temperature of the DPF; determining whether the inlet temperature is greater than a temperature threshold; if the inlet temperature is greater than the temperature threshold, controlling the outlet of the control valve connected to the second pipeline to be closed and controlling the outlet of the control valve connected to the first pipeline to be opened, so that the exhaust gas is discharged from the first pipeline through the filter, so that the particles in the exhaust gas are adsorbed by the filter; if the inlet temperature is not greater than the temperature threshold, controlling the outlet of the control valve connected to the second pipeline to be opened and controlling the outlet of the control valve connected to the first pipeline to be closed, so that the exhaust gas is discharged from the second pipeline.

[0146] Optionally, the diesel engine aftertreatment device further includes a PN measuring device, which is connected to the outlet of the ASC. The method further includes: obtaining the PN value of the exhaust gas tested by the PN measuring device, where the PN value is the value of the amount of particulate matter in the exhaust gas; determining whether the PN value is greater than a predetermined value, and if the PN value is greater than the predetermined value, controlling the outlet of the control valve connected to the second pipeline to be closed and controlling the outlet of the control valve connected to the first pipeline to be opened, so that the exhaust gas is discharged from the first pipeline through the filter, so that the particles in the exhaust gas are adsorbed by the filter; and if the PN value is not greater than the predetermined value, controlling the outlet of the control valve connected to the second pipeline to be open and controlling the outlet of the control valve connected to the first pipeline to be closed, so that the exhaust gas is discharged from the second pipeline.

[0147] Optionally, the diesel engine after-treatment device further includes a liquid storage tank connected to the SCR. The steps of obtaining the ammonia concentration introduced into the SCR include: obtaining the urea concentration of a urea aqueous solution introduced into the SCR, wherein the urea aqueous solution is sprayed from the liquid storage tank into the SCR; and calculating the concentration of ammonia generated after decomposition of urea based on the urea concentration and a chemical formula for urea hydrolysis to obtain the ammonia concentration.

[0148] Optionally, a one-way valve is provided on the second pipeline, which controls the outlet of the control valve connected to the second pipeline to be opened and controls the outlet of the control valve connected to the first pipeline to be closed, so that the exhaust gas is discharged from the second pipeline, including: controlling the control valve and the one-way valve to be opened, so that the exhaust gas is discharged from the second pipeline.

[0149] The devices in this article can be servers, PCs, PADs, mobile phones, etc.

[0150] The present application also provides a computer program product, which, when executed on a data processing device, is adapted to execute a program for initializing at least the following method steps:

[0151] Step S301, obtaining the concentration of ammonia gas introduced into the SCR, where the SCR uses ammonia gas to reduce the concentration of nitrogen oxides in the exhaust gas;

[0152] Step S302, determine whether the above-mentioned ammonia concentration is greater than the predetermined concentration. When the above-mentioned ammonia concentration is greater than the above-mentioned predetermined concentration, control the outlet of the above-mentioned control valve connected to the above-mentioned second pipeline to be closed and control the outlet of the above-mentioned control valve connected to the above-mentioned first pipeline to be opened, so that the above-mentioned exhaust gas is discharged from the above-mentioned first pipeline through the above-mentioned filter, so that excess ammonia is adsorbed by the above-mentioned filter.

[0153] Obviously, those skilled in the art will appreciate that the various modules or steps of the present invention described above can be implemented using a general-purpose computing device, can be centralized on a single computing device, or can be distributed across a network of multiple computing devices. They can be implemented using program code executable by the computing device, and thus, can be stored in a storage device and executed by the computing device. In some cases, the steps shown or described herein can be performed in a different order than that shown, or can be fabricated as separate integrated circuit modules, or multiple modules or steps can be fabricated as a single integrated circuit module. Thus, the present invention is not limited to any particular combination of hardware and software.

[0154] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0155] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the steps in the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0156] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0157] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 The steps for the function specified in one or more boxes.

[0158] In a typical configuration, a computing device includes one or more processors (CPUs), input / output interfaces, network interfaces, and memory.

[0159] The memory may include non-permanent memory in a computer-readable medium, random access memory (RAM) and / or non-volatile memory in the form of read-only memory (ROM) or flash RAM. The memory is an example of a computer-readable medium.

[0160] Computer-readable media includes permanent and non-permanent, removable and non-removable media that can be implemented by any method or technology to store information. The information can be computer-readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, compact disc read-only memory (CD-ROM), digital versatile disc (DVD) or other optical storage, magnetic cassettes, magnetic disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined herein, computer-readable media does not include transitory computer-readable media (transitory media), such as modulated data signals and carrier waves.

[0161] It should also be noted that the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, commodity, or apparatus that includes a series of elements includes not only those elements but also other elements not explicitly listed, or includes elements inherent to such process, method, commodity, or apparatus. In the absence of further limitations, an element defined by the phrase "comprises a ..." does not exclude the presence of other identical elements in the process, method, commodity, or apparatus that includes the element.

[0162] From the above description, it can be seen that the above embodiments of the present application achieve the following technical effects:

[0163] 1) The exhaust emission control method of the present application first obtains the ammonia concentration entering the SCR, which uses ammonia to reduce the concentration of nitrogen oxides in the exhaust gas. Then, the method determines whether the ammonia concentration is greater than a predetermined concentration. If the ammonia concentration is greater than the predetermined concentration, the outlet of the control valve connected to the second pipeline is closed, and the outlet of the control valve connected to the first pipeline is opened, so that the exhaust gas is discharged from the first pipeline through the filter, allowing excess ammonia to be adsorbed by the filter. This method determines whether the ammonia concentration entering the SCR is greater than a predetermined concentration, and if the ammonia concentration is greater than the predetermined concentration, the outlet of the intelligent control valve connected to the second pipeline is closed, allowing the exhaust gas to pass from the outlet of the ASC through the first pipeline to the inlet of the filter, allowing excess ammonia to be adsorbed by the filter, thereby achieving the purpose of reducing PN emissions, thereby solving the problem of PN emissions easily exceeding the standard in the prior art.

[0164] 2) The exhaust emission control device of the present application includes a first acquisition unit and a first control unit, wherein the first acquisition unit is used to acquire the ammonia concentration entering the SCR, which uses ammonia to reduce the concentration of nitrogen oxides in the exhaust gas; and the first control unit is used to determine whether the ammonia concentration is greater than a predetermined concentration. If the ammonia concentration is greater than the predetermined concentration, the control valve outlet connected to the second pipeline is closed and the control valve outlet connected to the first pipeline is opened, so that the exhaust gas is discharged from the first pipeline through the filter, and excess ammonia is adsorbed by the filter. This device determines whether the ammonia concentration entering the SCR is greater than the predetermined concentration, and if the ammonia concentration is greater than the predetermined concentration, the intelligent control valve outlet connected to the second pipeline is closed, so that the exhaust gas passes from the ASC outlet to the filter inlet through the first pipeline, so that excess ammonia is adsorbed by the filter, thereby achieving the purpose of reducing PN emissions, thereby solving the problem of PN emissions easily exceeding the standard in the prior art.

[0165] The above description is merely a preferred embodiment of the present application and is not intended to limit the present application. Various modifications and variations are possible for those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A method for controlling tail gas emissions, characterized in that: The method is applied to a diesel engine aftertreatment system, the diesel engine aftertreatment system comprising at least an SCR, an ASC, a control valve, and a filter connected in sequence, the outlet of the ASC being connected to the inlet of the filter via a first pipeline, the outlet of the ASC being connected to the outlet of the filter via a second pipeline, the control valve being disposed on the first pipeline and the second pipeline, and comprising: obtaining a concentration of ammonia gas introduced into the SCR, wherein the SCR uses ammonia gas to reduce a concentration of nitrogen oxides in the exhaust gas; determining whether the ammonia concentration is greater than a predetermined concentration; and if the ammonia concentration is greater than the predetermined concentration, controlling the control valve to close the outlet of the second pipeline and controlling the control valve to open the outlet of the first pipeline, so that the exhaust gas is discharged from the first pipeline through the filter, so that excess ammonia is adsorbed by the filter; The diesel engine aftertreatment system also includes a DPF, the outlet of which is connected to the inlet of the SCR. The method also includes: obtaining the carbon load in the DPF; determining whether the carbon load is within a predetermined range, and when the carbon load is less than a minimum value of the predetermined range or greater than a maximum value of the predetermined range, controlling the control valve to close the outlet of the second pipeline and controlling the control valve to open the outlet of the first pipeline, so that the exhaust gas is discharged from the first pipeline through the filter, so that the particles in the exhaust gas are adsorbed by the filter; when the carbon load is within the predetermined range, controlling the control valve to open the outlet of the second pipeline and closing the outlet of the control valve connected to the first pipeline, so that the exhaust gas is discharged from the second pipeline.

2. The method according to claim 1, characterized in that The method further comprises: When the ammonia concentration is not greater than the predetermined concentration, the control valve is controlled to open the outlet of the second pipeline and the control valve is controlled to close the outlet of the first pipeline, so that the exhaust gas is discharged from the second pipeline.

3. The method according to claim 1, characterized in that The method further comprises: Obtaining the inlet temperature of the DPF; Determine whether the inlet temperature is greater than a temperature threshold. If the inlet temperature is greater than the temperature threshold, control the control valve to close the outlet of the second pipeline and control the control valve to open the outlet of the first pipeline, so that the exhaust gas is discharged from the first pipeline through the filter, so that the particles in the exhaust gas are adsorbed by the filter. If the inlet temperature is not greater than the temperature threshold, control the control valve to open the outlet of the second pipeline and control the control valve to close the outlet of the first pipeline, so that the exhaust gas is discharged from the second pipeline.

4. The method according to claim 1, wherein The diesel engine aftertreatment system further includes a PN measurement device connected to an outlet of the ASC. The method further includes: Obtaining a PN value of the exhaust gas measured by the PN measuring device, where the PN value is a value of the amount of particulate matter in the exhaust gas; Determine whether the PN value is greater than a predetermined value. If the PN value is greater than the predetermined value, control the control valve to close the outlet of the second pipeline and control the control valve to open the outlet of the first pipeline, so that the exhaust gas is discharged from the first pipeline through the filter, so that the particles in the exhaust gas are adsorbed by the filter. If the PN value is not greater than the predetermined value, control the outlet of the control valve connected to the second pipeline to open and control the outlet of the control valve connected to the first pipeline to close, so that the exhaust gas is discharged from the second pipeline.

5. The method according to any one of claims 1 to 4, characterized in that The diesel engine aftertreatment system further includes a liquid storage tank connected to the SCR, and obtaining the concentration of ammonia gas flowing into the SCR includes: obtaining a urea concentration of a urea aqueous solution introduced into an SCR, wherein the urea aqueous solution is sprayed into the SCR from a storage tank; The concentration of ammonia generated after urea decomposition is calculated according to the urea concentration and the chemical formula of urea hydrolysis to obtain the ammonia concentration.

6. The method according to any one of claims 1 to 4, characterized in that A one-way valve is provided on the second pipeline, and the control valve is controlled to open the outlet of the second pipeline and the control valve is controlled to close the outlet of the first pipeline so that the exhaust gas is discharged from the second pipeline, including: The control valve and the one-way valve are both controlled to open, so that the exhaust gas is discharged from the second pipeline.

7. A tail gas emission control device, characterized in that: Applicable to a diesel engine aftertreatment system, the diesel engine aftertreatment system includes at least an SCR, an ASC, a control valve, and a filter connected in sequence, the outlet of the ASC is connected to the inlet of the filter via a first pipeline, the outlet of the ASC is connected to the outlet of the filter via a second pipeline, the control valve is provided on the first pipeline and the second pipeline, and the device includes: a first acquisition unit, configured to acquire a concentration of ammonia gas introduced into the SCR, wherein the SCR uses ammonia gas to reduce a concentration of nitrogen oxides in the exhaust gas; a first control unit, configured to determine whether the ammonia concentration is greater than a predetermined concentration, and, if the ammonia concentration is greater than the predetermined concentration, control the control valve to close the outlet of the second pipeline and control the control valve to open the outlet of the first pipeline, so that the exhaust gas is discharged from the first pipeline through the filter, so that excess ammonia is adsorbed by the filter; The diesel engine aftertreatment system also includes a DPF, the outlet of which is connected to the inlet of the SCR. The device also includes a second acquisition unit and a third control unit, wherein the second acquisition unit is used to obtain the carbon load in the DPF; the third control unit is used to determine whether the carbon load is within a predetermined range. When the carbon load is less than the minimum value of the predetermined range or greater than the maximum value of the predetermined range, the control valve is controlled to close the outlet of the second pipeline and the control valve is controlled to open the outlet of the first pipeline, so that the exhaust gas is discharged from the first pipeline through the filter, so that the particles in the exhaust gas are adsorbed by the filter. When the carbon load is within the predetermined range, the control valve is controlled to open the outlet of the second pipeline and the control valve is controlled to close the outlet of the first pipeline, so that the exhaust gas is discharged from the second pipeline.

8. A computer-readable storage medium, characterized in that The computer-readable storage medium includes a stored program, wherein when the program is executed, the device where the computer-readable storage medium is located is controlled to execute the exhaust emission control method according to any one of claims 1 to 6.

9. An electronic device, characterized in that: include: One or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and are configured to be executed by the one or more processors, and the one or more programs include a method for executing the exhaust emission control method described in any one of claims 1 to 6.

10. A diesel engine aftertreatment system, characterized in that: The exhaust gas control system comprises at least a controller, an SCR, an ASC, a control valve, and a filter connected in sequence, wherein the outlet of the ASC is connected to the inlet of the filter via a first pipeline, the outlet of the ASC is connected to the outlet of the filter via a second pipeline, the control valve is arranged on the first pipeline and on the second pipeline, and the controller is used to execute the exhaust emission control method according to any one of claims 1 to 6.

11. The system according to claim 10, wherein: The filter includes a DPF that is not coated with precious metal and has a high void ratio.

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