Post-treatment SCR dual-channel urea injection control method, device, system and engineering equipment

Abstract

This invention relates to the technical field of SCR aftertreatment, and provides a method, device, system, and engineering equipment for controlling two-way urea injection in an SCR aftertreatment system. The method includes the following steps: acquiring the engine's starting temperature and the current temperature of the preceding SCR; determining that the engine is in a cold start when its starting temperature is lower than a preset temperature; determining that the engine is in a hot start when its starting temperature is not lower than the preset temperature; determining that the engine is in a cold start and the current temperature of the preceding SCR reaches a first injection temperature, and then initiating urea injection through the preceding nozzles, where the first injection temperature is the temperature at which urea begins to hydrolyze; determining that the engine is in a hot start and the current temperature of the preceding SCR reaches a second injection temperature, and then initiating urea injection through the preceding nozzles. Thus, by distinguishing between the engine's cold and hot operating conditions, and by initiating urea injection through the preceding nozzles when the current temperature of the preceding SCR reaches the temperature at which urea begins to hydrolyze, nitrogen oxide emissions during engine cold starts can be reduced.

Description

Technical Field

[0001] This invention relates to the technical field of SCR post-treatment, and in particular to a method, apparatus, system and engineering equipment for controlling two-channel urea injection in SCR post-treatment. Background Technology

[0002] Selective catalytic reduction (SCR) technology is a highly efficient method for reducing nitrogen oxide (NOx) emissions from diesel engines. With increasing global awareness of environmental protection and increasingly stringent emission standards imposed by governments worldwide, SCR technology has been widely adopted in diesel engine vehicles such as heavy-duty trucks, buses, and off-road mobile machinery.

[0003] To meet emission requirements, most manufacturers currently use a two-stage SCR (Selective Catalytic Reduction) system in their exhaust aftertreatment systems. The SCR is the core unit of the aftertreatment system. The NH3 produced by the high-temperature hydrolysis of urea injected in a metered amount reacts with NOx in the exhaust gas on the catalyst surface of the SCR system, thereby achieving emission reduction.

[0004] However, the existing SCR urea injection temperature is a fixed calibrated value. When the engine is cold-started, the exhaust temperature is low and cannot reach the urea injection temperature, resulting in high cold-state nitrogen and oxygen emissions. Summary of the Invention

[0005] This invention provides a method, device, system, and engineering equipment for controlling dual-path urea injection in an aftertreatment SCR system, which addresses the high nitrogen and oxygen emissions during engine cold starts in existing technologies and can reduce nitrogen and oxygen emissions during engine cold starts without increasing hardware costs.

[0006] This invention provides a method for controlling the injection of urea in a two-channel SCR aftertreatment system, comprising the following steps:

[0007] Obtain the engine's start-up temperature and the current temperature of the preceding SCR stage;

[0008] When the engine's starting temperature is determined to be lower than a preset temperature, the engine is considered to be in a cold start; when the engine's starting temperature is determined to be not lower than the preset temperature, the engine is considered to be in a hot start.

[0009] When it is determined that the engine is in a cold start and the current temperature of the front-stage SCR reaches the first injection temperature, the front-stage nozzle opens urea injection, where the first injection temperature is the temperature at which urea begins to hydrolyze.

[0010] When it is determined that the engine is in a hot start and the current temperature of the pre-stage SCR reaches the second injection temperature, the pre-stage nozzle opens urea injection.

[0011] The post-treatment SCR dual-channel urea injection control method provided by the present invention further includes the following steps:

[0012] Obtain the current temperature of the downstream SCR;

[0013] When the current temperature of the downstream SCR reaches the third injection temperature, the downstream nozzle starts urea injection.

[0014] The post-treatment SCR dual-channel urea injection control method provided by the present invention further includes the following steps:

[0015] Determine the target urea injection volume;

[0016] When the target urea injection rate is determined to be no greater than the maximum urea injection rate under the condition of restricted crystallization, the target urea injection rate is the actual urea injection rate.

[0017] When the target urea injection rate is determined to be greater than the maximum urea injection rate under restricted crystallization conditions, the maximum urea injection rate under restricted crystallization conditions is the actual urea injection rate.

[0018] According to the present invention, a two-channel urea injection control method for aftertreatment SCR is provided, wherein the target urea injection quantity is determined by the upstream SCR temperature and the exhaust gas volume.

[0019] According to the post-treatment SCR dual-channel urea injection control method provided by the present invention, the target urea injection quantity of the pre-stage SCR is determined by the following formula:

[0020] The target urea injection rate of the pre-stage SCR = the content of nitrogen oxides upstream of the pre-stage SCR × the conversion coefficient of nitrogen oxides to ammonia × the SCR model efficiency × the conversion coefficient of ammonia to urea.

[0021] According to the present invention, a two-channel urea injection control method for a post-treatment SCR is provided, wherein the target urea injection quantity of the post-stage SCR is determined by the following formula:

[0022] The target urea injection rate of the subsequent SCR = (the basic urea injection rate of the subsequent SCR + the ammonia storage-regulated urea injection rate of the subsequent SCR) × ammonia to urea conversion coefficient.

[0023] The basic urea injection rate of the subsequent SCR = the content of nitrogen oxides upstream of the subsequent SCR × the conversion coefficient of nitrogen oxides to ammonia × the SCR model efficiency.

[0024] The ammonia storage adjustment urea injection rate of the subsequent SCR is calculated as follows: (target ammonia storage rate of the subsequent SCR - model ammonia storage rate of the subsequent SCR) / ammonia storage adjustment time.

[0025] According to the aftertreatment SCR dual-path urea injection control method provided by the present invention, the starting temperature of the engine is determined by the engine oil temperature and the engine coolant temperature.

[0026] The present invention also provides a post-treatment SCR dual-channel urea injection control device, comprising:

[0027] The acquisition module is used to acquire the engine's start-up temperature and the current temperature of the upstream SCR.

[0028] The storage module is used to store the operating parameters of the engine and the upstream SCR.

[0029] The processing module determines that the engine is in a cold start when its starting temperature is lower than a preset temperature; it determines that the engine is in a hot start when its starting temperature is not lower than the preset temperature; when the engine is in a cold start and the current temperature of the pre-stage SCR reaches the first injection temperature, the pre-stage nozzle starts urea injection, where the first injection temperature is the temperature at which urea begins to hydrolyze; and when the engine is in a hot start and the current temperature of the pre-stage SCR reaches the second injection temperature, the pre-stage nozzle starts urea injection.

[0030] The present invention also provides a dual-path urea injection system for aftertreatment SCR, comprising: a data acquisition module and a turbine, a pre-stage SCR, a DOC, a DPF and a post-stage SCR connected in sequence, wherein a pre-stage nozzle is provided between the turbine and the pre-stage SCR, and a post-stage nozzle is provided between the DPF and the post-stage SCR.

[0031] The data acquisition module includes a temperature sensor and a NOx sensor. The temperature sensor is used to collect the temperature of the engine, the pre-stage SCR, and the post-stage SCR. The NOx sensor is used to collect the NOx content in the exhaust gas entering the pre-stage SCR and the post-stage SCR.

[0032] It also includes the aforementioned post-treatment SCR dual-path urea injection control device.

[0033] The present invention also provides an engineering device, including the above-mentioned post-treatment SCR dual-path urea injection system.

[0034] An electronic device includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the post-processing SCR dual-channel urea injection control method as described above.

[0035] The present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the post-processing SCR dual-channel urea injection control method as described above.

[0036] The present invention also provides a computer program product, including a computer program that, when executed by a processor, implements the post-processing SCR dual-channel urea injection control method as described above.

[0037] Beneficial effects:

[0038] 1. By distinguishing between cold and hot operating conditions of the engine, when the current temperature of the front-stage SCR reaches the temperature at which urea begins to hydrolyze, the front-stage nozzle opens to inject urea. At this time, the urea solution hydrolyzes into ammonia in the exhaust pipe. The ammonia reacts with the NOx emitted by the engine inside the front-stage SCR catalyst, thereby reducing nitrogen oxide emissions under cold start conditions of the engine.

[0039] Second, the pre-stage SCR is mainly used to reduce NOx at low temperatures. It does not need to participate in the closed loop and only needs to use urea injection based on the target efficiency. It does not need to use urea injection based on ammonia storage, which saves test bench costs and simplifies calibration time.

[0040] Third, by determining the target urea injection rate based on the temperature and exhaust gas volume of the pre-stage SCR, and by determining the actual injection rate based on the target urea injection rate and the maximum urea injection rate under the condition of limiting crystallization, the risk of urea crystallization in the pre-stage SCR at low temperatures can be reduced. Attached Figure Description

[0041] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0042] Figure 1 This is a schematic diagram of the structure of the post-treatment SCR dual-path urea injection system provided by the present invention.

[0043] Figure 2 This is a schematic diagram of the post-treatment SCR two-channel urea injection method provided by the present invention.

[0044] Figure 3 This is a schematic diagram of the structure of the electronic device provided by the present invention.

[0045] Figure label:

[0046] 1. Turbine; 2. Pre-stage SCR; 3. DOC; 4. DPF; 5. Post-stage SCR; 6. Pre-stage nozzle; 7. Post-stage nozzle; 810. Processor; 820. Communication interface; 830. Memory; 840. Communication bus. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0048] To facilitate understanding of the aftertreatment SCR dual-path urea injection control method, device, system and engineering equipment provided by this invention, its application background is first introduced. SCR technology is an efficient method to reduce nitrogen oxide (NOx) emissions from diesel engines.

[0049] To meet emission requirements, most manufacturers currently use a two-stage SCR (Selective Catalytic Reduction) system in their exhaust aftertreatment systems. The SCR is the core unit of the aftertreatment system. The NH3 produced by the high-temperature hydrolysis of urea injected in a metered amount reacts with NOx in the exhaust gas on the catalyst surface of the SCR system, thereby achieving emission reduction.

[0050] However, the existing SCR urea injection temperature is a fixed calibrated value. When the engine is cold-started, the exhaust temperature is low and cannot reach the urea injection temperature, resulting in high cold-state nitrogen and oxygen emissions.

[0051] To address the aforementioned problems, this invention provides a method, device, system, and engineering equipment for controlling dual-path urea injection in an aftertreatment SCR system, which can reduce nitrogen oxide emissions during engine cold starts without increasing hardware costs.

[0052] The following is combined Figures 1-3 This invention describes the post-treatment SCR two-channel urea injection control method, apparatus, system, and engineering equipment.

[0053] In this embodiment of the invention, reference is made to Figure 1 The aftertreatment SCR (Selective Catalytic Reduction) dual-injection urea system adopts a dual-injection SCR system, which includes a turbine 1, a front-stage SCR2, a DOC3 (diesel oxidation catalyst), a DPF4 (diesel particulate filter), and a rear-stage SCR5 connected in sequence.

[0054] The front-stage SCR2 uses a closely coupled SCR (closed couple Selective Catalytic Reduction) system, which is located closer to the turbine 1 and therefore has a faster response speed. In addition, due to the higher exhaust temperature at the exhaust port, it is conducive to the rapid decomposition of urea solution and the generation of ammonia, which can enhance the engine's ability to remove NOx under cold conditions. The rear-stage SCR5 is located further away from the turbine 1 and is used to remove most of the NOx downstream.

[0055] DOC3 provides a strong oxidizing effect, which can oxidize carbon monoxide and hydrocarbons into carbon dioxide and water, and oxidize some of the nitric oxide into nitrogen dioxide, thereby increasing the exhaust temperature.

[0056] DPF4 is used to filter solid particulate matter (mainly soot) in engine exhaust, which can reduce particulate matter in the exhaust gas and thus reduce particulate matter emissions.

[0057] A pre-stage nozzle 6 is provided between the turbine 1 and the pre-stage SCR2, and a post-stage nozzle 7 is provided between the DPF4 and the post-stage SCR5.

[0058] The aftertreatment SCR dual-path urea injection system also includes a data acquisition module, which includes a temperature sensor and a NOx sensor. The temperature sensor can collect the temperature of the engine, the front-stage SCR2 and the rear-stage SCR5, and the NOx sensor can collect the NOx content in the exhaust gas entering the front-stage SCR2 and the rear-stage SCR5.

[0059] Figure 2 This is a flowchart illustrating the aftertreatment SCR dual-channel urea injection control method provided by the present invention. This method can be applied to vehicle controllers, such as ECU (Electronic Control Unit, vehicle computer), etc. The ECU can acquire and store the parameters of each of the above sensors, as well as store and transmit the corresponding limit values ​​of each parameter.

[0060] Reference Figure 2 The post-treatment SCR dual-channel urea injection control method includes the following steps:

[0061] Step 10: Obtain the engine start-up temperature and the current temperature of the front-stage SCR2.

[0062] As a complex thermodynamic system, the engine's temperature is affected by a variety of factors. Engine oil temperature and coolant temperature can be regarded as representative of the temperature of different parts of the engine. Therefore, the engine temperature can be indirectly reflected by monitoring the engine oil temperature and coolant temperature.

[0063] There are several options for calculating engine temperature. For example, a weighted average method can be used to estimate engine temperature by considering the weights of the heat capacity distribution of oil and water in the engine cooling system. Model predictive control can also be used to predict engine temperature based on historical data and trends of oil and water temperatures. Alternatively, empirical formulas can be used to estimate engine temperature based on the specific model and design of the engine, using empirical formulas provided by the manufacturer.

[0064] Of course, the engine temperature calculation methods include, but are not limited to, the methods listed above. Other methods are also applicable, and the specific method can be selected according to actual needs and operating conditions. No specific restrictions are imposed in this embodiment of the invention.

[0065] The current temperature of the pre-stage SCR2 can be acquired by a temperature sensor. Specifically, the current temperature of the pre-stage SCR2 can be acquired by the built-in temperature sensor; it can also be acquired by acquiring the temperature upstream of the pre-stage SCR2, i.e., the intake temperature; or it can be acquired by acquiring the upstream temperature and then inputting this temperature value into the SCR catalyst carrier temperature model to obtain the current temperature value of the pre-stage SCR2.

[0066] It is understood that the pre-stage SCR2 is not limited to the temperature acquisition method mentioned above. Any other temperature acquisition method that can acquire the temperature of the pre-stage SCR2 is applicable. The specific method can be selected according to actual needs and operating conditions. No specific restrictions are imposed in this embodiment of the invention.

[0067] Step 11: When the engine's starting temperature is lower than the preset temperature, the engine is considered a cold start; when the engine's starting temperature is not lower than the preset temperature, the engine is considered a hot start.

[0068] Specifically, different tests or studies may specify different preset temperatures for the engine based on specific purposes or conditions. This means that in some cases, the preset temperature may vary depending on the specific requirements of the test or the goals of the study. For example, in the cold-state WHTC (Worldwide Harmonized Transient Cycle) test and the initial stage of the cold-state PEMS (Portable Emissions Measurement Systems) test, the engine temperature starts at around 30 degrees Celsius.

[0069] In a specific embodiment of the present invention, when the engine's starting temperature is 40 degrees Celsius, the engine is considered a cold start; when the engine's starting temperature is not less than 40 degrees Celsius, the engine is considered a hot start. The engine's starting temperature is compared with a preset temperature to determine whether it is a cold or hot start.

[0070] Step 12: When the engine is cold-started and the current temperature of the front-stage SCR2 reaches the first injection temperature, the front-stage nozzle 6 starts urea injection. The first injection temperature is the temperature at which urea begins to hydrolyze.

[0071] When the current temperature of the front-stage SCR2 reaches the temperature at which urea begins to hydrolyze, the front-stage nozzle 6 opens to inject urea. At this time, the urea solution hydrolyzes into ammonia in the exhaust pipe. The ammonia reacts with the NOx emitted by the engine inside the front-stage SCR2 catalyst, thereby reducing nitrogen oxide emissions under cold start conditions.

[0072] As a specific embodiment of the present invention, the first spraying temperature can be set to 130°C to 140°C, and the specific temperature is determined in the SCR calibration.

[0073] Step 13: When the engine is hot-started and the current temperature of the front-stage SCR2 reaches the second injection temperature, the front-stage nozzle 6 starts urea injection.

[0074] In engine hot start mode, when the current temperature of the front-stage SCR2 reaches the second injection temperature, the front-stage nozzle 6 starts urea injection. At this time, the rear-stage SCR5 carrier mainly performs NOx catalytic reduction, while the front-stage SCR2 mainly plays an auxiliary role.

[0075] As a specific embodiment of the present invention, the second spraying temperature can be set to 170°C to 180°C, and the specific temperature is determined in the SCR calibration.

[0076] Step 14: Obtain the current temperature of the downstream SCR5. When the current temperature of the downstream SCR5 reaches the third injection temperature, the downstream nozzle 7 starts urea injection.

[0077] After the engine starts, as the exhaust temperature gradually increases, when the current temperature of the downstream SCR5 reaches the third injection temperature, the downstream nozzle 7 injects urea to ensure the effectiveness of the entire system in NOx reduction.

[0078] The current temperature of the downstream SCR5 can be acquired through a temperature sensor. Specifically, the current temperature of the downstream SCR5 can be acquired through a built-in temperature sensor; it can also be acquired by acquiring the temperature upstream of the downstream SCR5, i.e., the intake temperature; or it can be acquired by acquiring the upstream temperature and then inputting this temperature value into the SCR catalyst carrier temperature model to obtain the current temperature value of the downstream SCR5.

[0079] It is understood that the temperature acquisition method of the downstream SCR5 is not limited to the above-mentioned method. Any other temperature acquisition method that can acquire the temperature of the downstream SCR5 is applicable. The specific method can be selected according to actual needs and operating conditions. No specific restrictions are imposed in this embodiment of the invention.

[0080] In one embodiment of the present invention, in order to reduce the risk of urea crystallization, the post-treatment SCR dual-channel urea injection control method further includes the following steps:

[0081] Step 100: Determine the target urea injection volume.

[0082] Specifically, the target urea injection quantity of the pre-stage SCR2 is determined by the pre-stage SCR2 temperature and exhaust gas volume.

[0083] More specifically, the target urea injection quantity for the pre-stage SCR2 is determined by the following formula:

[0084] The target urea injection rate of the pre-stage SCR2 = the target ammonia injection rate of the pre-stage SCR2 × the ammonia-to-urea conversion coefficient = the content of nitrogen oxides upstream of the pre-stage SCR2 × the nitrogen oxide-to-ammonia conversion coefficient × the SCR model efficiency × the ammonia-to-urea conversion coefficient.

[0085] Among them, upstream NO of the pre-stage SCR2 X This represents the NOx content in the exhaust gas emitted from the engine's exhaust port. It is the basis for determining how much urea is needed to effectively reduce NOx emissions, and the specific amount can be determined through NOx testing.

[0086] NO X The NH3 conversion factor reflects the amount of ammonia (NH3) required for an effective reaction with NOx. Different NOx compounds may require different proportions of NH3 for complete reaction. The specific reaction equations are shown below:

[0087] 4NO + 4NH3 + O2 → 4N2 + 6H2O;

[0088] 6NO2 + 8NH3 → 7N2 + 12H2O;

[0089] 2NO2 + 4NH3 + O2 → 3N2 + 6H2O.

[0090] SCR model efficiency refers to the actual effect of an SCR system in treating nitrogen oxides (NOx) in diesel engine exhaust, that is, under given conditions, what proportion of NOx can be converted into harmless nitrogen and water. SCR model efficiency is affected by a variety of factors, including but not limited to temperature, catalyst type, space velocity, moisture and sulfides, system design, etc. Therefore, SCR model efficiency can be determined according to actual operating conditions.

[0091] Therefore, the target ammonia injection rate of the pre-stage SCR2 = the content of nitrogen oxides upstream of the pre-stage SCR2 × the conversion coefficient of nitrogen oxides to ammonia × the efficiency of the SCR model.

[0092] The NH3-urea conversion factor reflects how much ammonia can be produced per unit mass of urea, which is crucial for accurately calculating the required amount of urea. The standard equation for the urea hydrolysis reaction is:

[0093] (NH2)2CO+H2O→2NH3+CO2; however, in practical applications, the conversion coefficient of NH3 to urea is often affected by factors such as temperature, so the conversion coefficient of NH3 to urea can be determined according to the actual working conditions.

[0094] Finally, the target urea injection rate of the pre-stage SCR2 is obtained as follows: upstream nitrogen oxide content of the pre-stage SCR2 × nitrogen oxide to ammonia conversion coefficient × SCR model efficiency × ammonia to urea conversion coefficient.

[0095] The target urea injection quantity for the SCR5 stage is calculated using the following formula:

[0096] The target urea injection rate of the downstream SCR5 = (the basic urea injection rate of the downstream SCR5 + the ammonia storage-regulated urea injection rate of the downstream SCR5) × ammonia to urea conversion coefficient.

[0097] Among them, the basic urea injection amount of the subsequent SCR5 = the content of nitrogen oxides upstream of the subsequent SCR5 × the conversion coefficient of nitrogen oxides to ammonia × the efficiency of the SCR model.

[0098] The ammonia storage adjustment urea injection rate for the subsequent SCR5 is calculated as follows: (target ammonia storage capacity of the subsequent SCR5 - ammonia storage capacity of the subsequent SCR model) / ammonia storage adjustment time.

[0099] The above technical solution can determine the target urea injection volume for the pre-stage SCR2 and post-stage SCR5.

[0100] Step 101: When the target urea injection amount is determined to be no greater than the maximum urea injection amount under the condition of restricted crystallization, the target urea injection amount is the actual urea injection amount.

[0101] Specifically, in diesel engine SCR systems, the maximum urea injection quantity under conditions limiting crystallization is a crucial consideration. If the urea injection quantity is too high, exceeding the maximum permissible value under current conditions, excess urea solution will accumulate in the exhaust system, forming crystals and causing blockages. The maximum urea injection quantity needs to be determined by comprehensively considering factors such as temperature, urea solution concentration, exhaust flow rate, and system design. When the target urea injection quantity is not greater than the maximum urea injection quantity under conditions limiting crystallization, it indicates that the risk of urea crystallization is relatively low even when injecting urea at the target quantity. Therefore, the target urea injection quantity can be used as the actual urea injection quantity.

[0102] Specifically, when the engine is cold-started, the maximum ammonia injection amount limited by the front-stage crystallization boundary is obtained by interpolation of the cold-start crystallization boundary map based on the temperature and exhaust gas volume of the front-stage SCR2; when the engine is hot-started, the maximum ammonia injection amount limited by the front-stage crystallization boundary is obtained by interpolation of the hot-start crystallization boundary map based on the temperature and exhaust gas volume of the front-stage SCR2; the maximum urea injection amount limited by the hot-start crystallization boundary map is greater than the maximum urea injection amount limited by the cold-start crystallization boundary map.

[0103] Step 102: When the target urea injection rate is greater than the maximum urea injection rate under the restricted crystallization condition, the maximum urea injection rate under the restricted crystallization condition is the actual urea injection rate.

[0104] When the target urea injection volume is greater than the maximum urea injection volume under the condition of limiting crystallization, it indicates that there is a risk of crystallization when injecting urea according to the target urea injection volume. Therefore, the maximum urea injection volume under the condition of limiting crystallization can be used as the actual urea injection volume.

[0105] By adopting the above technical solution, the risk of urea crystallization in the pre-stage SCR2 at low temperatures can be reduced. The pre-stage SCR2 is mainly used to reduce NOx at low temperatures and does not need to participate in closed-loop operation. It only needs to use urea injection based on the target efficiency, without the need for urea injection based on ammonia storage. This saves on test bench costs and simplifies calibration time.

[0106] The following describes the post-treatment SCR dual-channel urea injection control device provided by the present invention. The post-treatment SCR dual-channel urea injection control device described below can be referred to in correspondence with the post-treatment SCR dual-channel urea injection method described above.

[0107] A post-treatment SCR dual-channel urea injection control device, comprising:

[0108] The acquisition module is used to acquire the engine's start-up temperature and the current temperature of the upstream SCR2.

[0109] The storage module is used to store the operating parameters of the engine and the preceding SCR2 stage;

[0110] The processing module determines that the engine is in a cold start when the engine's starting temperature is lower than the preset temperature; it determines that the engine is in a hot start when the engine's starting temperature is not lower than the preset temperature; when the engine is in a cold start and the current temperature of the front-stage SCR2 reaches the first injection temperature, the front-stage nozzle 6 starts urea injection, the first injection temperature being the temperature at which urea begins to hydrolyze; when the engine is in a hot start and the current temperature of the front-stage SCR2 reaches the second injection temperature, the front-stage nozzle 6 starts urea injection.

[0111] On the other hand, the present invention also provides an aftertreatment SCR dual-path urea injection system, comprising: a data acquisition module and a turbine 1, a front-stage SCR2, a DOC3, a DPF4, and a rear-stage SCR5 connected in sequence, wherein a front-stage nozzle 6 is provided between the turbine 1 and the front-stage SCR2, and a rear-stage nozzle 7 is provided between the DPF4 and the rear-stage SCR5; the data acquisition module includes a temperature sensor and a NOx sensor, wherein the temperature sensor is used to acquire the temperature of the engine, the front-stage SCR2, and the rear-stage SCR5; and the NOx sensor is used to acquire the NOx content in the exhaust gas entering the front-stage SCR2 and the rear-stage SCR5; and also includes the aforementioned aftertreatment SCR dual-path urea injection control device.

[0112] On the other hand, the present invention also provides an engineering device, including the above-mentioned post-treatment SCR dual-path urea injection system.

[0113] Specifically, engineering equipment includes, but is not limited to, heavy trucks, trailers, excavators, roadheaders, bulldozers, road rollers, and concrete pump trucks, or mechanical equipment such as tower cranes, construction hoists, and material hoists.

[0114] On the other hand, the present invention also provides an electronic device, Figure 3 An example is a schematic diagram of the physical structure of an electronic device, such as... Figure 3As shown, the electronic device may include: a processor 810, a communication interface 820, a memory 830, and a communication bus 840, wherein the processor 810, the communication interface 820, and the memory 830 communicate with each other through the communication bus 840. The processor 810 can call logical instructions in the memory 830 to execute a post-processing SCR dual-channel urea injection method, which includes: acquiring the engine's starting temperature and the current temperature of the pre-stage SCR2; determining that the engine is cold-started when the engine's starting temperature is lower than a preset temperature; determining that the engine is hot-started when the engine's starting temperature is not lower than the preset temperature; determining that the engine is cold-started and the current temperature of the pre-stage SCR2 reaches a first injection temperature, and the pre-stage nozzle 6 starts urea injection, the first injection temperature being the temperature at which urea begins hydrolysis; determining that the engine is hot-started and the current temperature of the pre-stage SCR2 reaches a second injection temperature, and the pre-stage nozzle 6 starts urea injection.

[0115] Furthermore, the logical instructions in the aforementioned memory 830 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0116] On the other hand, the present invention also provides a computer program product, which includes a computer program that can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the post-processing SCR dual-channel urea injection method provided by the above methods. The method includes: acquiring the engine's starting temperature and the current temperature of the pre-stage SCR2; determining that the engine is cold-started when the engine's starting temperature is less than a preset temperature; determining that the engine is hot-started when the engine's starting temperature is not less than the preset temperature; determining that the engine is cold-started and the current temperature of the pre-stage SCR2 reaches a first injection temperature, and the pre-stage nozzle 6 starts urea injection, the first injection temperature being the temperature at which urea begins to hydrolyze; determining that the engine is hot-started and the current temperature of the pre-stage SCR2 reaches a second injection temperature, and the pre-stage nozzle 6 starts urea injection.

[0117] In another aspect, the present invention also provides a non-transitory computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the post-processing SCR dual-channel urea injection method provided by the methods described above. The method includes: acquiring the engine's starting temperature and the current temperature of the pre-stage SCR2; determining that the engine is in a cold start when the engine's starting temperature is lower than a preset temperature; determining that the engine is in a hot start when the engine's starting temperature is not lower than the preset temperature; determining that the engine is in a cold start and the current temperature of the pre-stage SCR2 reaches a first injection temperature, and the pre-stage nozzle 6 initiates urea injection, the first injection temperature being the temperature at which urea begins hydrolysis; determining that the engine is in a hot start and the current temperature of the pre-stage SCR2 reaches a second injection temperature, and the pre-stage nozzle 6 initiates urea injection.

[0118] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0119] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0120] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A post-processed SCR two-path urea injection control method, characterized in that, The method comprises the following steps: obtaining the starting temperature of the engine and the current temperature of the front-stage SCR; determining that the engine is cold starting when the starting temperature of the engine is less than a preset temperature; determining that the engine is hot starting when the starting temperature of the engine is not less than the preset temperature; opening the urea injection of the front-stage nozzle when the engine is cold starting and the current temperature of the front-stage SCR reaches a first starting temperature, the first starting temperature being the temperature at which urea starts to hydrolyze; opening the urea injection of the front-stage nozzle when the engine is hot starting and the current temperature of the front-stage SCR reaches a second starting temperature; The method further comprises the following steps: determining the target urea injection amount; determining that the target urea injection amount is the actual urea injection amount when the target urea injection amount is not greater than the maximum urea injection amount under the condition of limiting crystallization; determining that the maximum urea injection amount under the condition of limiting crystallization is the actual urea injection amount when the target urea injection amount is greater than the maximum urea injection amount under the condition of limiting crystallization; The target urea injection amount of the front-stage SCR is determined by the following formula: Target urea injection amount of front-stage SCR = Content of nitrogen oxides upstream of front-stage SCR × Conversion coefficient of nitrogen oxides to ammonia × SCR model efficiency × Conversion coefficient of ammonia to urea.

2. The post-processing SCR two-path urea injection control method of claim 1, wherein, The method further comprises the following steps: obtaining the current temperature of the rear-stage SCR; opening the urea injection of the rear-stage nozzle when the current temperature of the rear-stage SCR reaches a third starting temperature.

3. The post-processing SCR two-path urea injection control method of claim 1, wherein, The SCR model efficiency and / or the conversion coefficient of ammonia to urea is affected by the temperature of the front-stage SCR.

4. The post-processed SCR two-path urea injection control method of claim 2, wherein, The target urea injection amount of the rear-stage SCR is determined by the following formula: Target urea injection amount of rear-stage SCR = (Basic urea injection amount of rear-stage SCR + Ammonia storage adjustment urea injection amount of rear-stage SCR) × Conversion coefficient of ammonia to urea; Basic urea injection amount of rear-stage SCR = Content of nitrogen oxides upstream of rear-stage SCR × Conversion coefficient of nitrogen oxides to ammonia × SCR model efficiency; Ammonia storage adjustment urea injection amount of rear-stage SCR = (Target ammonia storage amount of rear-stage SCR - Model ammonia storage amount of rear-stage SCR) / Ammonia storage adjustment time.

5. A post-processed SCR two-path urea injection control apparatus, characterized by, The method comprises: an obtaining module for obtaining the starting temperature of the engine and the current temperature of the front-stage SCR; a storage module for storing the operating parameters of the engine and the front-stage SCR; a processing module for determining that the engine is cold starting when the starting temperature of the engine is less than a preset temperature; determining that the engine is hot starting when the starting temperature of the engine is not less than the preset temperature; determining that the engine is cold starting and the current temperature of the front-stage SCR reaches a first starting temperature, the first starting temperature being the temperature at which urea starts to hydrolyze; determining that the engine is hot starting and the current temperature of the front-stage SCR reaches a second starting temperature, the front-stage nozzle opening the urea injection; The processing module is further used for: determining the target urea injection amount; When the target urea injection amount is determined to be no more than the maximum urea injection amount in the case of limiting crystallization, the target urea injection amount is the actual urea injection amount; When the target urea injection amount is determined to be more than the maximum urea injection amount in the case of limiting crystallization, the maximum urea injection amount in the case of limiting crystallization is the actual urea injection amount; The target urea injection amount of the front-stage SCR is determined by the following formula: Target urea injection amount of the front-stage SCR = content of nitrogen oxides upstream of the front-stage SCR * conversion coefficient of nitrogen oxides to ammonia * model efficiency of the SCR * conversion coefficient of ammonia to urea.

6. A post-processed SCR two-path urea injection system characterized by, Comprise: A data acquisition module and a turbine, a front-stage SCR, a DOC, a DPF and a rear-stage SCR connected in sequence, a front-stage nozzle arranged between the turbine and the front-stage SCR, and a rear-stage nozzle arranged between the DPF and the rear-stage SCR; The data acquisition module comprises a temperature sensor and a NOx sensor, the temperature sensor is used to acquire the temperature of the engine, the front-stage SCR and the rear-stage SCR, and the NOx sensor is used to acquire the content of NOx in the exhaust gas entering the front-stage SCR and the rear-stage SCR; Further comprise the aftertreatment SCR two-way urea injection control device of claim 5.

7. An engineering apparatus characterised in that, Further comprise the aftertreatment SCR two-way urea injection system of claim 6.

8. An electronic device comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, The processor executes the program to realize the aftertreatment SCR two-way urea injection control method of any one of claims 1 to 4.

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