A method, apparatus and medium for urea injection quantity adjustment for exhaust gas treatment

Abstract

The embodiment of the application discloses a urea injection amount adjusting method, device and medium for tail gas treatment, and belongs to the technical field of engines. The method solves the problems that excessive urea injection increases cost and easily leads to the decline or even failure of the aftertreatment conversion efficiency under the transient working condition of the engine. The method comprises the following steps: determining the aftertreatment efficiency of the SCR aftertreatment system based on the NOx measurement values corresponding to the upstream and downstream of the SCR aftertreatment system when the engine operates under the steady working condition; determining a correction factor based on engine monitoring data when the engine operates under the sudden acceleration transient working condition; determining an adjusting coefficient based on the aftertreatment efficiency, the correction factor, the instantaneous acceleration characteristic parameter corresponding to the engine and the temperature parameter corresponding to the SCR aftertreatment system; and adjusting the urea injection system based on the adjusting coefficient to reduce the urea injection amount of the SCR aftertreatment system under the sudden acceleration transient working condition.

Description

TECHNICAL FIELD

[0001] The present application relates to the engine technical field, and in particular to a urea injection amount adjusting method, device and medium for exhaust treatment. BACKGROUND

[0002] NOx in engine exhaust emission is a strictly regulated emission, which will cause serious air pollution. Especially under engine transient conditions, it is easy to produce large NOx emissions. At present, SCR aftertreatment (Selective Catalytic Reduction, selective catalytic reduction system) is the most common technology for reacting NOx emissions in diesel engine exhaust. The SCR aftertreatment is installed with a urea injection system, which can control the urea injection system according to the size of the NOx emission measured by the NOx sensor upstream of the aftertreatment, and spray 32.5% urea solution into the SCR aftertreatment through the urea nozzle, to catalytically reduce NOx to generate nitrogen and water, thereby reducing diesel engine exhaust NOx emissions.

[0003] However, under engine transient conditions, excessive urea injection will increase costs and easily cause ammonia leakage, and under low aftertreatment temperature conditions, excessive urea injection will increase the risk of aftertreatment crystallization, resulting in a decrease in aftertreatment conversion efficiency or even failure. SUMMARY

[0004] The embodiments of the present application provide a urea injection amount adjusting method, device and medium for exhaust treatment, which are used to solve the following technical problems: under engine transient conditions, excessive urea injection will increase costs and easily cause a decrease in aftertreatment conversion efficiency or even failure.

[0005] The embodiments of the present application adopt the following technical solutions:

[0006] The embodiments of the present application provide a urea injection amount adjusting method for exhaust treatment. In the case of engine operation in a steady state condition, the aftertreatment efficiency corresponding to the SCR aftertreatment system is determined based on the NOx measurement values corresponding to the upstream and downstream of the SCR aftertreatment system. In the case of engine operation in a sudden acceleration transient condition, a correction factor is determined based on engine monitoring data. A correction factor is determined based on the aftertreatment efficiency, the correction factor, the instantaneous acceleration characteristic parameter corresponding to the engine, and the temperature parameter corresponding to the SCR aftertreatment system. In the sudden acceleration transient condition, the urea injection system is adjusted based on the correction factor to reduce the urea injection amount of the SCR aftertreatment system.

[0007] The embodiment of the application determines a correction factor by monitoring data under the transient working condition of engine sudden acceleration, and calculates an adjustment coefficient based on multiple parameters to accurately adjust the urea injection amount, thereby avoiding excessive urea injection and saving urea consumption. As the reducing agent of the SCR system, urea reduces the overall operating cost and improves economic benefits by optimizing the urea injection amount. Excessive urea injection is prone to cause urea crystallization, which in turn blocks the SCR catalyst. The embodiment of the application accurately adjusts the urea injection amount to reduce the risk of urea crystallization and protect the stable operation of the SCR aftertreatment system.

[0008] In an implementation manner of the application, the aftertreatment efficiency of the SCR aftertreatment system is determined based on the NOx measurement values corresponding to the upstream and downstream of the SCR aftertreatment system, specifically including: obtaining a first NOx measurement value by the nitrogen oxygen sensor arranged at the upstream of the SCR aftertreatment system; obtaining a second NOx measurement value by the nitrogen oxygen sensor arranged at the downstream of the SCR aftertreatment system; in the case that the ratio between the first NOx measurement value and the second NOx measurement value is not less than a first preset value, determining that the SCR aftertreatment system is in a normal operating state, and taking the ratio as the aftertreatment efficiency; in the case that the ratio is less than a second preset value, determining that the SCR aftertreatment system is in an abnormal operating state, and performing fault alarm.

[0009] In an implementation manner of the application, the correction factor is determined based on engine monitoring data, specifically including: determining the corresponding smoke limit fuel quantity in the pre-set smoke limit fuel quantity table based on the type parameter corresponding to the engine; wherein the pre-set smoke limit fuel quantity table includes multiple engine type parameters, and also includes the smoke limit fuel quantity in a mapping relationship with the multiple engine type parameters; determining the actual injection quantity corresponding to the engine based on the engine monitoring data; determining the difference between the smoke limit fuel quantity and the actual injection quantity; determining the ratio between the difference and the smoke limit fuel quantity, and taking the ratio as the correction factor.

[0010] In an implementation manner of the application, before the adjustment coefficient is determined based on the aftertreatment efficiency, the correction factor, the instantaneous acceleration characteristic parameter corresponding to the engine and the temperature parameter corresponding to the SCR aftertreatment system, the method further includes: obtaining the first MAP table corresponding to the engine; wherein the first MAP table is used to represent the relationship between the correction factor, the instantaneous acceleration characteristic parameter corresponding to the engine and the pre-set first adjustment coefficient; and obtaining the first CUR table corresponding to the engine; wherein the first CUR table is used to represent the relationship between the aftertreatment efficiency and the pre-set second adjustment coefficient; and obtaining the second CUR table corresponding to the engine; wherein the second CUR table is used to represent the relationship between the temperature parameter corresponding to the SCR aftertreatment system and the pre-set third adjustment coefficient; so as to determine the adjustment coefficient by the first MAP table, the first CUR table and the second CUR table.

[0011] In an implementation form of the application, the adjustment coefficient is determined based on the aftertreatment efficiency, the correction factor, the instantaneous acceleration characteristic parameter corresponding to the engine, and the temperature parameter corresponding to the SCR aftertreatment system, and specifically comprises: determining a first adjustment coefficient to be adjusted in a first MAP table based on the correction factor and the instantaneous acceleration characteristic parameter corresponding to the engine; determining a second adjustment coefficient to be adjusted in a first CUR table based on the aftertreatment efficiency; determining a third adjustment coefficient to be adjusted in a second CUR table based on the temperature parameter corresponding to the SCR aftertreatment system; and determining the adjustment coefficient based on the product of the first adjustment coefficient to be adjusted, the second adjustment coefficient to be adjusted, and the third adjustment coefficient to be adjusted.

[0012] In an implementation form of the application, the urea injection system is adjusted based on the adjustment coefficient to reduce the urea injection amount of the SCR aftertreatment system during the sudden acceleration transient operating condition, and specifically comprises: obtaining the urea injection amount of the urea injection system corresponding to the steady operating condition; determining a urea correction injection amount based on the product of the adjustment coefficient and the urea injection amount; and controlling the urea injection system to inject the urea into the SCR aftertreatment system based on the urea correction injection amount.

[0013] In an implementation form of the application, before the urea injection system is adjusted based on the adjustment coefficient, the method further comprises: obtaining the operating state of the engine; obtaining the operating condition of the engine; and obtaining the adjustment coefficient and the urea injection amount of the urea injection system corresponding to the steady operating condition; and in the case that the operating state of the engine is a fault-free state, the operating condition of the engine is a sudden acceleration transient operating condition, and the transient correction function is enabled, the urea injection system is adjusted based on the adjustment coefficient and the urea injection amount of the urea injection system corresponding to the steady operating condition.

[0014] In an implementation form of the application, the operating condition of the engine is obtained, and specifically comprises: determining the engine speed and the engine injection amount based on the engine monitoring data; determining a reference threshold in a smoke limit oil amount threshold MAP table based on the engine speed and the engine injection amount; determining the difference between the smoke limit oil amount corresponding to the engine and the actual injection amount; comparing the difference with the reference threshold, and in the case that the difference is not less than the reference threshold, determining that the engine is in a steady operating condition; and in the case that the difference is less than the reference threshold, determining that the engine is in a sudden acceleration transient operating condition.

[0015] The embodiment of the present application provides a urea injection amount adjusting device for tail gas treatment, comprising: at least one processor; and a memory connected with the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to: in the case that an engine is operated in a steady state condition, determine a corresponding aftertreatment efficiency of an SCR aftertreatment system based on NOx measurement values corresponding to upstream and downstream of the SCR aftertreatment system respectively; in the case that the engine is operated in a sudden acceleration transient condition, determine a correction factor based on engine monitoring data; determine an adjusting coefficient based on the aftertreatment efficiency, the correction factor, a corresponding instantaneous acceleration characteristic parameter of the engine and a corresponding temperature parameter of the SCR aftertreatment system; and in the sudden acceleration transient condition, adjust a urea injection system based on the adjusting coefficient to reduce urea injection amount of the SCR aftertreatment system.

[0016] The embodiment of the present application provides a nonvolatile computer storage medium, which stores computer executable instructions, and the computer executable instructions are configured to: in the case that an engine is operated in a steady state condition, determine a corresponding aftertreatment efficiency of an SCR aftertreatment system based on NOx measurement values corresponding to upstream and downstream of the SCR aftertreatment system respectively; in the case that the engine is operated in a sudden acceleration transient condition, determine a correction factor based on engine monitoring data; determine an adjusting coefficient based on the aftertreatment efficiency, the correction factor, a corresponding instantaneous acceleration characteristic parameter of the engine and a corresponding temperature parameter of the SCR aftertreatment system; and in the sudden acceleration transient condition, adjust a urea injection system based on the adjusting coefficient to reduce urea injection amount of the SCR aftertreatment system.

[0017] The above at least one technical scheme adopted by the embodiment of the present application can achieve the following beneficial effects: in the sudden acceleration transient condition of the engine, the correction factor is determined through monitoring data, and the adjusting coefficient is calculated based on multiple parameters to accurately adjust the urea injection amount, so that the excessive injection of urea is avoided, and the consumption of urea is saved. As a reducing agent of the SCR system, the urea reduces the overall operating cost and improves the economic benefit by optimizing the urea injection amount. Excessive urea injection is easy to cause urea crystallization, and then block the SCR catalyst, the embodiment of the present application accurately adjusts the urea injection amount to reduce the risk of urea crystallization and protect the stable operation of the SCR aftertreatment system. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to make the technical solutions in the application or the prior art clearer, the accompanying drawings needed in the description of the embodiments or the prior art will be briefly introduced. Obviously, the accompanying drawings in the following description only represent some embodiments described in the application, and other drawings can be obtained by those skilled in the art without any creative effort on the basis of these drawings. In the drawings:

[0019] Figure 1 A flow chart of a urea injection amount adjusting method for exhaust gas treatment is provided for the embodiments of the application.

[0020] Figure 2 A schematic diagram of an engine device is provided for the embodiments of the application.

[0021] Figure 3 A logic diagram of a urea injection amount adjusting method for exhaust gas treatment is provided for the embodiments of the application.

[0022] Figure 4 A structural schematic diagram of a urea injection amount adjusting device for exhaust gas treatment is provided for the embodiments of the application.

[0023] 200: a urea injection amount adjusting device for exhaust gas treatment, 201: a processor, 202: a memory. DETAILED DESCRIPTION

[0024] The embodiments of the application provide a urea injection amount adjusting method, device and medium for exhaust gas treatment.

[0025] In order to make those skilled in the art better understand the technical solutions in the application, the technical solutions in the embodiments of the application will be clearly and completely described in the following with reference to the accompanying drawings. Obviously, the described embodiments are only some of the embodiments of the application, but not all the embodiments. Based on the embodiments of the application, all other embodiments obtained by those skilled in the art without any creative effort should fall within the protection scope of the application.

[0026] The technical solutions of the embodiments of the application will be described in detail below with reference to the accompanying drawings.

[0027] Figure 1 A flow chart of a urea injection amount adjusting method for exhaust gas treatment is provided for the embodiments of the application, as shown in Figure 1 The urea injection amount adjusting method for exhaust gas treatment includes the following steps:

[0028] S101, in the case that the engine operates in a steady state condition, the aftertreatment efficiency of the SCR aftertreatment system is determined based on the NOx measurement values corresponding to the upstream and downstream of the SCR aftertreatment system respectively.

[0029] In an embodiment of the present application, the engine speed and the engine fuel injection amount are determined based on the engine monitoring data. Based on the engine speed and the engine fuel injection amount, a reference threshold is determined in the smoke limit fuel injection threshold MAP table. The difference between the smoke limit fuel injection amount corresponding to the engine and the actual fuel injection amount is determined. The difference is compared with the reference threshold. In the case that the difference is not less than the reference threshold, it is determined that the engine is in a steady state operating condition. In the case that the difference is less than the reference threshold, it is determined that the engine is in a sudden acceleration transient operating condition.

[0030] Specifically, the engine speed is acquired in real time by an engine speed sensor. The engine fuel injection amount is determined according to the engine speed, the intake air amount, the coolant temperature, the throttle position, etc. The smoke limit fuel injection threshold MAP table is provided in the embodiment of the present application, which contains the smoke limit fuel injection threshold corresponding to different engine speeds and operating conditions. The reference threshold is searched in the smoke limit fuel injection threshold MAP table according to the current engine speed and operating condition.

[0031] Further, the actual monitored fuel injection amount is compared with the reference threshold searched from the MAP table, and the difference between them is calculated. If the difference is not less than the reference threshold, it indicates that the actual fuel injection amount of the current engine is equivalent to or slightly higher than the preset smoke limit fuel injection threshold, and the engine is in a relatively stable operating state. In this case, it is considered that the engine is in a steady state operating condition.

[0032] Further, if the difference is less than the reference threshold, it indicates that the actual fuel injection amount of the current engine is much lower than the preset smoke limit fuel injection threshold, which may be caused by sudden acceleration or sharp increase of load of the engine. In this case, it is considered that the engine is in a sudden acceleration transient operating condition.

[0033] In an embodiment of the present application, the first NOx measurement value is acquired by the nitrogen oxygen sensor arranged upstream of the SCR aftertreatment system. The second NOx measurement value is acquired by the nitrogen oxygen sensor arranged downstream of the SCR aftertreatment system. In the case that the ratio between the first NOx measurement value and the second NOx measurement value is not less than the first preset value, it is determined that the SCR aftertreatment system is in a normal operating state, and the ratio is taken as the aftertreatment efficiency. In the case that the ratio is less than the second preset value, it is determined that the SCR aftertreatment system is in an abnormal operating state, and fault alarm is performed.

[0034] Specifically, upstream and downstream of the SCR aftertreatment system in the embodiments of the present application are respectively provided with nitrogen oxygen sensors. The upstream nitrogen oxygen sensor measures the NOx concentration entering the SCR system, i.e., a first NOx measurement value, which reflects the NOx level in the original emission of the engine. The downstream nitrogen oxygen sensor measures the remaining NOx concentration in the exhaust gas after the treatment of the SCR system, i.e., a second NOx measurement value. The second NOx measurement value reflects the conversion effect of the SCR system on NOx. By comparing the NOx measurement values upstream and downstream, the aftertreatment efficiency of the SCR system can be calculated, i.e., the aftertreatment efficiency is indirectly evaluated using the ratio between the second NOx measurement value and the first NOx measurement value.

[0035] Further, in the case where the engine is operated in a steady state condition, when the ratio between the first NOx measurement value and the second NOx measurement value is not less than a first preset value, for example, 0.5, indicating that at least half of the NOx is converted and no reverse reaction or leakage of NOx occurs, it is determined that the SCR system is in a normal operating state. At this time, the ratio can be directly used as an evaluation index of the aftertreatment efficiency. If the ratio is less than a second preset value, it indicates that the conversion efficiency of the SCR system is much lower than expected, and there may be problems such as catalyst deactivation, urea injection system failure, urea solution quality problem or system leakage. At this time, the system should give a fault alarm and may trigger further fault diagnosis and maintenance procedures.

[0036] S102, in the case where the engine is operated in a sudden acceleration transient condition, a correction factor is determined based on engine monitoring data.

[0037] In an embodiment of the present application, based on the corresponding type parameters of the engine, the corresponding smoke limit fuel quantity is determined in the preset smoke limit fuel quantity table; wherein the preset smoke limit fuel quantity table includes a plurality of engine type parameters, and also includes smoke limit fuel quantities that have a mapping relationship with the plurality of engine type parameters. Based on the engine monitoring data, the actual injection quantity corresponding to the engine is determined. The difference between the smoke limit fuel quantity and the actual injection quantity is determined. The ratio between the difference and the smoke limit fuel quantity is determined, and the ratio is taken as the correction factor.

[0038] Specifically, in the case where the engine is operated in a sudden acceleration transient condition, there will be a peak value of NOx emission. The embodiments of the present application are provided with a preset smoke limit fuel quantity table, which contains a table of a plurality of engine type parameters and their corresponding smoke limit fuel quantities, and these parameters at least include one of engine model, displacement, power and emission standard. According to the type parameters of the current engine, such as model, displacement, etc., the corresponding smoke limit fuel quantity is found in the preset smoke limit fuel quantity table.

[0039] Further, real-time data of the engine is acquired by an engine management system or other monitoring devices, including fuel injection amount, rotation speed, load, etc. The actual fuel injection amount of the current engine is extracted from the monitoring data. The smoke limit value fuel injection amount found is compared with the actual fuel injection amount, a difference value is calculated, the calculated difference value is divided by the smoke limit value fuel injection amount, a ratio is obtained, and the ratio is taken as a correction factor. The ratio reflects the deviation between the actual fuel injection amount and the smoke limit value fuel injection amount. The correction factor is used to evaluate whether the actual fuel injection amount is reasonable and whether adjustment is needed, and the range is 0-1. If the correction factor is close to 1, it means that the actual fuel injection amount is close to the smoke limit value fuel injection amount and is within a reasonable range. If the correction factor deviates greatly, the fuel injection system needs to be checked or the fuel injection amount needs to be adjusted. According to the value of the correction factor, corresponding adjustment measures are taken. For example, if the correction factor is large, it means that the actual fuel injection amount is too much, and it may be necessary to reduce the fuel injection amount or check whether the fuel injection nozzle is leaking. If the correction factor is small, it means that the actual fuel injection amount is insufficient, and it may be necessary to increase the fuel injection amount or check whether the fuel supply system is normal.

[0040] S103, determining the adjustment coefficient based on the aftertreatment efficiency, the correction factor, the instantaneous acceleration characteristic parameter corresponding to the engine, and the temperature parameter corresponding to the SCR aftertreatment system.

[0041] In an embodiment of the present application, a first MAP table corresponding to the engine is acquired, wherein the first MAP table is used to represent the relationship among the correction factor, the instantaneous acceleration characteristic parameter corresponding to the engine, and a preset first adjustment coefficient. A first CUR table corresponding to the engine is acquired, wherein the first CUR table is used to represent the relationship between the aftertreatment efficiency and a preset second adjustment coefficient, and a second CUR table corresponding to the engine is acquired, wherein the second CUR table is used to represent the relationship between the temperature parameter corresponding to the SCR aftertreatment system and a preset third adjustment coefficient. The adjustment coefficient is determined by the first MAP table, the first CUR table, and the second CUR table.

[0042] Specifically, the first MAP table in the embodiment of the present application is used to represent the relationship among the correction factor, the instantaneous acceleration characteristic parameter corresponding to the engine, and the preset first adjustment coefficient. The horizontal and vertical coordinates of the first MAP table can be the correction factor and the exhaust gas flow, but are not limited to the exhaust gas flow, and can be a characteristic parameter representing the instantaneous acceleration of the engine, such as the intake flow, the torque, etc. The greater the correction factor and the exhaust gas flow, the smaller the value read in the correction factor MAP.

[0043] Specifically, the first CUR table in the embodiment of the present application is used to represent the relationship between the aftertreatment efficiency and the preset second adjustment coefficient. The second CUR table is used to represent the relationship between the corresponding temperature parameter of the SCR aftertreatment system and the preset third adjustment coefficient. The aftertreatment temperature CUR is a number less than 1, which can be calibrated according to the level of the aftertreatment conversion efficiency at each temperature. When the temperature interval is greater than the temperature interval with high aftertreatment conversion efficiency, the calibrated coefficient gradually decreases with the increase of the temperature. Conversely, when the temperature interval is less than the temperature interval with high aftertreatment conversion efficiency, the calibrated coefficient gradually decreases with the decrease of the temperature. The aftertreatment temperature CUR can also be represented by other parameters, such as the ambient temperature turbine after temperature, etc.

[0044] In an embodiment of the present application, based on the correction factor and the corresponding instantaneous acceleration characteristic parameter of the engine, the first to-be-adjusted coefficient is determined in the first MAP table. Based on the aftertreatment efficiency, the second to-be-adjusted coefficient is determined in the first CUR table. Based on the corresponding temperature parameter of the SCR aftertreatment system, the third to-be-adjusted coefficient is determined in the second CUR table. Based on the product of the first to-be-adjusted coefficient, the second to-be-adjusted coefficient and the third to-be-adjusted coefficient, the adjustment coefficient is determined.

[0045] Specifically, the correction factor and the instantaneous acceleration characteristic parameter of the current engine are obtained. In the first MAP table, the corresponding preset first adjustment coefficient is found according to the combination of the correction factor and the instantaneous acceleration characteristic parameter. The finding result is taken as the first to-be-adjusted coefficient. The aftertreatment efficiency of the current aftertreatment system is obtained. In the first CUR table, the corresponding preset second adjustment coefficient is found according to the aftertreatment efficiency, and the finding result is taken as the second to-be-adjusted coefficient. The temperature parameter of the current SCR aftertreatment system is obtained. In the second CUR table, the corresponding preset third adjustment coefficient is found according to the temperature parameter, and the finding result is taken as the third to-be-adjusted coefficient.

[0046] S104, in the sudden acceleration transient operating condition, the urea injection system is adjusted based on the adjustment coefficient to reduce the urea injection amount of the SCR aftertreatment system.

[0047] In an embodiment of the present application, the running state of the engine is obtained; and the running condition of the engine is obtained; and the adjustment coefficient and the urea injection amount of the urea injection system corresponding to the steady state condition are obtained. In the case that the running state of the engine is a fault-free state, the running condition is a sudden acceleration transient condition, and the transient correction function is turned on, the urea injection system is adjusted based on the adjustment coefficient and the urea injection amount of the urea injection system corresponding to the steady state condition.

[0048] Specifically, the operating state of the engine generally includes various information, such as whether there is a fault, whether it is in a warm-up stage, whether it has reached a normal working temperature, and the like. The embodiments of the present application determine that the engine is currently in a fault-free state by reading the data of various sensors, such as temperature sensors, pressure sensors, fault indicator lights, and the like. The operating condition of the engine refers to the current working condition of the engine, including parameters such as speed, load, acceleration, and the like. These parameters determine the performance requirements and emission characteristics of the engine. When the speed of the engine is monitored to rapidly rise in a short time, and the load also increases accordingly, it is determined that the engine is currently in a sudden acceleration transient operating condition. The calculated adjustment coefficient is obtained, and the urea injection amount corresponding to the urea injection system in the steady state operating condition is obtained.

[0049] Further, in the case where the operating state of the engine is a fault-free state, the operating condition is a sudden acceleration transient operating condition, and the transient correction function is turned on, the urea injection system is adjusted in real time according to the adjustment coefficient and the urea injection amount in the steady state operating condition.

[0050] In an embodiment of the present application, the urea injection amount corresponding to the urea injection system in the steady state operating condition is obtained. Based on the product of the adjustment coefficient and the urea injection amount, the urea correction injection amount is determined. Based on the urea correction injection amount, the urea injection system is controlled to inject into the SCR aftertreatment system.

[0051] Specifically, by multiplying the urea injection amount in the steady state operating condition by the adjustment coefficient, the urea correction injection amount that adapts to the current engine operating condition and performance requirements is obtained. After the urea correction injection amount is determined, the control system sends instructions to the urea injection system to adjust the injection parameters of the urea pump, such as injection time, injection pressure, and the like, to ensure that the urea can be accurately injected into the SCR aftertreatment system according to the corrected injection amount. The catalyst in the SCR aftertreatment system reacts with the ammonia gas produced by the decomposition of urea to convert NOx into harmless nitrogen and water vapor, thereby achieving the purpose of reducing emissions.

[0052] According to the logic, if it is determined that the engine is in a sudden acceleration transient operating condition, there will be a peak value of NOx emissions at this time. By increasing the urea injection amount through the closed-loop injection system, not all of the urea will be converted in the transient operating condition. The existing calibration method reduces the original engine NOx emissions by delaying the main injection angle, and reduces the urea injection amount through the urea injection closed-loop logic system, but it will worsen the fuel economy. Or by adjusting the ammonia nitrogen ratio to reduce urea injection, this method has a large impact area and will cause the NOx emissions to increase in different temperature or other steady state operating conditions, which has the risk of causing the NOx emissions to exceed the regulatory limits. The embodiments of the present application monitor the transient operating condition of the engine, and relatively reduce the urea injection through the aftertreatment efficiency CUR, the aftertreatment temperature CUR, and the correction factor MAP. This reduces the customer cost, reduces the risk of ammonia leakage and crystallization.

[0053] Figure 2 A schematic diagram of an engine device is provided for the embodiments of the present application, as shown in Figure 2 The engine device includes an engine and an SCR aftertreatment. The engine includes an intake manifold and an exhaust manifold. The SCR aftertreatment further includes a urea injection system. NOx in the exhaust emission of the engine is a strictly regulated emission, which can cause serious air pollution. In particular, under transient operating conditions of the engine, large NOx emissions are prone to occur. At present, the SCR aftertreatment is the most commonly used technology for reacting NOx emissions in the exhaust of a diesel engine. The SCR aftertreatment is installed with a urea injection system, which can perform closed-loop control according to the size of NOx emissions measured by an upstream NOx sensor of the aftertreatment, inject 32.5% urea solution into the interior of the SCR aftertreatment through a urea nozzle, catalytically reduce NOx to generate nitrogen and water, and reduce the NOx emission of the diesel engine exhaust.

[0054] Figure 3 A urea injection amount adjustment logic diagram for exhaust treatment is provided for the embodiments of the present application, as shown in Figure 3 First, the operating conditions of the engine are detected. The difference between the smoke limit fuel amount corresponding to the engine and the actual fuel injection amount is determined. Based on the engine speed and the engine fuel injection amount, a reference threshold is determined in the smoke limit fuel amount threshold MAP table. In the case where the difference is not less than the reference threshold, it is determined that the engine is in a steady operating condition. In the case where the difference is less than the reference threshold, it is determined that the engine is in a sudden acceleration transient operating condition. If it is a steady operating condition, the aftertreatment efficiency corresponding to the SCR aftertreatment system is determined according to the NOx measurement values respectively corresponding to the upstream and downstream of the SCR aftertreatment system. If the aftertreatment efficiency is not less than a constant 1, it is a normal operating state. If it is less than a constant 2, it is a fault state and a fault alarm is performed. At the same time, the urea solution injection amount corresponding to the injection system under the steady operating condition is obtained. If it is a sudden acceleration transient operating condition, the difference between the smoke limit fuel amount and the actual fuel injection amount is determined. The ratio between the difference and the smoke limit fuel amount is determined as a correction factor. Based on the correction factor MAP, the aftertreatment temperature CUR, and the aftertreatment efficiency CUR, the adjustment coefficient is determined. According to the product between the adjustment coefficient and the urea injection amount, the urea corrected injection amount is determined.

[0055] Figure 4 A structural schematic diagram of a urea injection amount adjustment device for exhaust treatment is provided for the embodiments of the present application. As shown in Figure 4As shown, the urea injection amount adjusting device 200 for tail gas treatment comprises: at least one processor 201; and a memory 202 connected in communication with the at least one processor 201; wherein the memory 202 stores instructions executable by the at least one processor 201, and the instructions are executed by the at least one processor 201 to enable the at least one processor 201 to: in the case that the engine is running in a steady state condition, determine a corresponding aftertreatment efficiency of the SCR aftertreatment system based on NOx measurement values corresponding to upstream and downstream of the SCR aftertreatment system respectively; in the case that the engine is running in a sudden acceleration transient condition, determine a correction factor based on engine monitoring data; determine an adjusting coefficient based on the aftertreatment efficiency, the correction factor, a corresponding instantaneous acceleration characteristic parameter of the engine, and a corresponding temperature parameter of the SCR aftertreatment system; and in the sudden acceleration transient condition, adjust the urea injection system based on the adjusting coefficient to reduce the urea injection amount to the SCR aftertreatment system.

[0056] The non-volatile computer storage medium provided by the embodiments of the present application stores computer executable instructions, which are configured to: in the case that the engine is running in a steady state condition, determine a corresponding aftertreatment efficiency of the SCR aftertreatment system based on NOx measurement values corresponding to upstream and downstream of the SCR aftertreatment system respectively; in the case that the engine is running in a sudden acceleration transient condition, determine a correction factor based on engine monitoring data; determine an adjusting coefficient based on the aftertreatment efficiency, the correction factor, a corresponding instantaneous acceleration characteristic parameter of the engine, and a corresponding temperature parameter of the SCR aftertreatment system; and in the sudden acceleration transient condition, adjust the urea injection system based on the adjusting coefficient to reduce the urea injection amount to the SCR aftertreatment system.

[0057] Each of the embodiments of the present application is described in a progressive manner, and the same or similar parts of each of the embodiments can be referred to each other. Each of the embodiments focuses on the difference from other embodiments. In particular, for the device, equipment, and non-volatile computer storage medium embodiments, since they are basically similar to the method embodiments, the description is relatively simple, and the relevant parts can be referred to the part of the method embodiments.

[0058] The above only describes the embodiments of the present application and is not intended to limit the present application. The embodiments of the present application can be variously changed and modified by those skilled in the art. The modifications or replacements do not make the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for adjusting the amount of urea injection for exhaust gas treatment, characterized by, The method comprises: In the case that the engine operates in a steady state condition, the aftertreatment efficiency corresponding to the SCR aftertreatment system is determined based on the NOx measurement values corresponding to the upstream and downstream of the SCR aftertreatment system respectively; In the case that the engine operates in a sudden acceleration transient condition, a correction factor is determined based on the engine monitoring data, specifically comprising: the actual fuel injection amount corresponding to the engine is determined based on the engine monitoring data; the difference between the smoke limit fuel injection amount and the actual fuel injection amount is determined; the ratio between the difference and the smoke limit fuel injection amount is determined, and the ratio is taken as the correction factor; The adjustment coefficient is determined based on the aftertreatment efficiency, the correction factor, the instantaneous acceleration characteristic parameter corresponding to the engine, and the temperature parameter corresponding to the SCR aftertreatment system, specifically comprising: the first adjustment coefficient to be adjusted is determined in the first MAP table based on the correction factor and the instantaneous acceleration characteristic parameter corresponding to the engine; wherein the first MAP table is used to represent the relationship between the correction factor, the instantaneous acceleration characteristic parameter corresponding to the engine, and the preset first adjustment coefficient; the second adjustment coefficient to be adjusted is determined in the first CUR table based on the aftertreatment efficiency; wherein the first CUR table is used to represent the relationship between the aftertreatment efficiency and the preset second adjustment coefficient; the third adjustment coefficient to be adjusted is determined in the second CUR table based on the temperature parameter corresponding to the SCR aftertreatment system; wherein the second CUR table is used to represent the relationship between the temperature parameter corresponding to the SCR aftertreatment system and the preset third adjustment coefficient; the adjustment coefficient is determined based on the product of the first adjustment coefficient to be adjusted, the second adjustment coefficient to be adjusted, and the third adjustment coefficient to be adjusted; In the sudden acceleration transient condition, the urea injection system is adjusted based on the adjustment coefficient to reduce the urea injection amount of the SCR aftertreatment system.

2. The method of claim 1, wherein the urea injection amount is adjusted based on the amount of ammonia slip. The aftertreatment efficiency corresponding to the SCR aftertreatment system is determined based on the NOx measurement values corresponding to the upstream and downstream of the SCR aftertreatment system respectively, specifically comprising: The first NOx measurement value is obtained by the nitrogen oxygen sensor arranged upstream of the SCR aftertreatment system; The second NOx measurement value is obtained by the nitrogen oxygen sensor arranged downstream of the SCR aftertreatment system; In the case that the ratio between the first NOx measurement value and the second NOx measurement value is not less than the first preset value, it is determined that the SCR aftertreatment system is in a normal operating state, and the ratio is taken as the aftertreatment efficiency; In the case that the ratio is less than the second preset value, it is determined that the SCR aftertreatment system is in an abnormal operating state, and a fault alarm is performed.

3. The method of claim 1, wherein the urea injection amount is adjusted based on the amount of ammonia slip. Before the correction factor is determined based on the engine monitoring data, the method further comprises: The corresponding smoke limit fuel injection amount is determined in the preset smoke limit fuel injection amount table based on the type parameter corresponding to the engine; wherein the preset smoke limit fuel injection amount table includes a plurality of engine type parameters, and also includes the smoke limit fuel injection amount which has a mapping relationship with the plurality of engine type parameters.

4. The method of claim 1, wherein the urea injection amount is adjusted based on the amount of ammonia slip. Before the determining the adjustment coefficient based on the post-processing efficiency, the correction factor, the instantaneous acceleration characteristic parameter corresponding to the engine, and the temperature parameter corresponding to the SCR post-processing system, the method further comprises: obtaining a first MAP table corresponding to the engine; and obtaining a first CUR table corresponding to the engine; and obtaining a second CUR table corresponding to the engine; determining the adjustment coefficient through the first MAP table, the first CUR table, and the second CUR table.

5. The method of claim 1, wherein the method is used for urea injection amount adjustment for exhaust gas treatment. The adjusting the urea injection system based on the adjustment coefficient to reduce the urea injection amount of the SCR post-processing system in the sudden acceleration transient operating condition specifically comprises: obtaining a urea injection amount corresponding to the urea injection system in a steady operating condition; determining a urea correction injection amount based on a product of the adjustment coefficient and the urea injection amount; controlling the urea injection system to inject the urea into the SCR post-processing system based on the urea correction injection amount.

6. The method of claim 5, wherein the amount of urea injection is adjusted based on the amount of ammonia slip. Before the adjusting the urea injection system based on the adjustment coefficient, the method further comprises: obtaining an operating state of the engine; and obtaining an operating condition of the engine; and obtaining the adjustment coefficient and a urea injection amount corresponding to the urea injection system in a steady operating condition; in a case that the operating state of the engine is a fault-free state, the operating condition is the sudden acceleration transient operating condition, and a transient correction function is turned on, adjusting the urea injection system based on the adjustment coefficient and the urea injection amount corresponding to the urea injection system in the steady operating condition.

7. The method of claim 6, wherein the amount of urea injection is adjusted based on the amount of ammonia slip. The obtaining the operating condition of the engine specifically comprises: determining an engine speed and an engine injection amount based on the engine monitoring data; determining a reference threshold in a smoke limit injection amount threshold MAP table based on the engine speed and the engine injection amount; determining a difference between a smoke limit injection amount corresponding to the engine and an actual injection amount; comparing the difference with the reference threshold, and determining that the engine is in a steady operating condition in a case that the difference is not less than the reference threshold; determining that the engine is in a sudden acceleration transient operating condition in a case that the difference is less than the reference threshold.

8. A urea injection amount regulating device for exhaust gas treatment, characterized in that: The device comprises a memory for storing computer program instructions and a processor for executing the program instructions, wherein when the computer program instructions are executed by the processor, the device is triggered to execute the method of any one of claims 1-7.

9. A non-transitory computer storage medium storing computer-executable instructions that, when executed, cause a computer to perform: The computer executable instructions can execute the method of any one of claims 1-7. The computer executable instructions can execute the method of any one of claims 1-7.

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