CN111120053B - Method and device for controlling urea injection - Google Patents

Method and device for controlling urea injection Download PDF

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Publication number
CN111120053B
CN111120053B CN201911370186.9A CN201911370186A CN111120053B CN 111120053 B CN111120053 B CN 111120053B CN 201911370186 A CN201911370186 A CN 201911370186A CN 111120053 B CN111120053 B CN 111120053B
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nitrogen
emission
scr system
determining
oxygen
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CN111120053A (en
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杨新春
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Beiqi Foton Motor Co Ltd
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Beiqi Foton Motor Co Ltd
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/18—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control
    • F01N3/20—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control specially adapted for catalytic conversion ; Methods of operation or control of catalytic converters
    • F01N3/2066—Selective catalytic reduction [SCR]
    • F01N3/208—Control of selective catalytic reduction [SCR], e.g. dosing of reducing agent
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2560/00—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics
    • F01N2560/02—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics the means being an exhaust gas sensor
    • F01N2560/026—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics the means being an exhaust gas sensor for measuring or detecting NOx
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2570/00—Exhaust treating apparatus eliminating, absorbing or adsorbing specific elements or compounds
    • F01N2570/14—Nitrogen oxides
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2610/00—Adding substances to exhaust gases
    • F01N2610/02—Adding substances to exhaust gases the substance being ammonia or urea
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
    • Y02A50/20—Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/12—Improving ICE efficiencies
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/40—Engine management systems

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Health & Medical Sciences (AREA)
  • Toxicology (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Exhaust Gas After Treatment (AREA)

Abstract

The disclosure relates to a control method and a device for urea injection, relates to the technical field of vehicle control, and is applied to a vehicle, wherein an SCR system is arranged on the vehicle, and the method comprises the following steps: the method comprises the steps of obtaining actual nitrogen and oxygen emission measured by a nitrogen and oxygen sensor, setting the nitrogen and oxygen sensor at the downstream of an SCR system, determining a control coefficient according to working parameters and emission deviation if the working parameters and the SCR system at the current moment meet control conditions, determining the emission deviation as a difference value between the actual nitrogen and oxygen emission and a target nitrogen and oxygen emission, determining the target nitrogen and oxygen emission according to basic nitrogen and oxygen emission preset by a vehicle, taking the product of basic injection quantity and the control coefficient as actual injection quantity, controlling the SCR system to inject urea solution according to the actual injection quantity, and determining the basic injection quantity according to the basic nitrogen and oxygen emission and the working parameters. The method and the device can adjust the injection amount of the SCR system in real time according to the actual nitrogen and oxygen emission amount of the downstream of the SCR system, and can improve the accuracy and the adaptability of the SCR system.

Description

Method and device for controlling urea injection
Technical Field
The disclosure relates to the technical field of vehicle control, in particular to a control method and device for urea injection.
Background
Diesel engines are widely used in various vehicles due to their excellent economical efficiency and power performance, but since diesel engines contain nitrogen oxides (NOx) in exhaust gas generated when the diesel engines combust diesel oil, which causes environmental pollution, it is necessary to provide a purification device at an exhaust port of the diesel engine to reduce nitrogen oxides in the exhaust gas. The purification device is generally an SCR (Selective Catalytic Reduction) system, which reduces nitrogen oxides in the exhaust gas by injecting a urea solution, decomposing the urea solution into ammonia gas by means of heat in the exhaust gas, and reducing the nitrogen oxides into nitrogen gas and water by using the ammonia gas as a reducing agent.
In general, because there may be an error in the original discharge amount of the diesel engine calibrated in advance and an error in the concentration of the urea solution during production and equipment, the urea solution injected by the SCR system may not match the original discharge amount. Meanwhile, as the SCR system is continuously aged, the conversion efficiency of the SCR system is also reduced, which may cause the urea solution injected by the SCR system to be insufficient to convert nitrogen oxides in the exhaust gas. The accuracy and fitness of the SCR system are reduced.
Disclosure of Invention
The purpose of the present disclosure is to provide a control method and device for urea injection, so as to solve the problem of low accuracy and adaptability of the SCR system in the prior art.
In order to achieve the above object, according to a first aspect of an embodiment of the present disclosure, there is provided a control method for injecting urea, applied to a vehicle on which a selective catalytic reduction SCR system is provided, the method including:
acquiring actual nitrogen and oxygen emission measured by a nitrogen and oxygen sensor, wherein the nitrogen and oxygen sensor is arranged at the downstream of the SCR system;
if the working parameters at the current moment and the SCR system both meet the control conditions, determining a control coefficient according to the working parameters and the emission deviation, wherein the emission deviation is the difference value between the actual nitrogen and oxygen emission and the target nitrogen and oxygen emission, and the target nitrogen and oxygen emission is determined according to the basic nitrogen and oxygen emission preset by the vehicle;
and taking the product of the basic injection quantity and the control coefficient as an actual injection quantity, and controlling the SCR system to inject the urea solution according to the actual injection quantity, wherein the basic injection quantity is determined according to the basic nitrogen and oxygen emission quantity and the working parameters.
Optionally, before the obtaining the actual amount of nitrogen and oxygen emissions measured by the nitrogen and oxygen sensor, the method further comprises:
determining the conversion efficiency of the SCR system and the ammonia storage amount of the SCR system according to the working parameters, and determining the basic injection amount according to a preset ammonia-nitrogen ratio, the basic nitrogen-oxygen emission amount, the conversion efficiency and the ammonia storage amount;
and determining the target nitrogen and oxygen emission according to the basic nitrogen and oxygen emission.
Optionally, if both the current working parameter and the SCR system satisfy the control condition, determining a control coefficient according to the working parameter and the emission amount deviation includes:
if the working parameters belong to the normal parameter range and the working state of the SCR system is a normal state, determining that the working parameters and the SCR system both meet the control conditions;
determining target correction time and target correction step length according to the working parameters;
and taking the emission deviation, the target correction time and the target correction step length as the input of a preset proportional-integral controller to obtain the control coefficient output by the proportional-integral controller.
Optionally, the operating parameters include: temperature, pressure and exhaust flow, said determining a target correction time based on said operating parameters comprising:
determining initial correction time and the target correction step length according to the temperature and the exhaust flow;
determining an environment correction value and a working boundary correction value of the SCR system according to the temperature and the pressure;
and taking the product of the initial correction time, the environment correction value and the working boundary correction value as the target correction time.
Optionally, after determining a control coefficient according to the operating parameter and the emission deviation if the operating parameter at the current time and the SCR system both satisfy the control condition, the method further includes:
if the control coefficient is larger than or equal to a first coefficient threshold value, or the control coefficient is smaller than a second coefficient threshold value, setting the control coefficient as a preset initial control coefficient, wherein the first coefficient threshold value is larger than the second coefficient threshold value.
Optionally, after determining a control coefficient according to the operating parameter and the emission deviation if the operating parameter at the current time and the SCR system both satisfy the control condition, the method further includes:
and if the emission deviation is larger than the emission deviation at the previous moment and the control coefficient is larger than the control coefficient at the previous moment, determining that the SCR system is in an ammonia leakage state, and setting the control coefficient as a preset initial control coefficient.
According to a second aspect of the embodiments of the present disclosure, there is provided a control device for injecting urea, applied to a vehicle on which a Selective Catalytic Reduction (SCR) system is provided, the device including:
the acquisition module is used for acquiring the actual nitrogen and oxygen emission amount measured by a nitrogen and oxygen sensor, and the nitrogen and oxygen sensor is arranged at the downstream of the SCR system;
the first determining module is used for determining a control coefficient according to the working parameters and emission deviation if the working parameters at the current moment and the SCR system both meet control conditions, wherein the emission deviation is a difference value between the actual nitrogen and oxygen emission and a target nitrogen and oxygen emission, and the target nitrogen and oxygen emission is determined according to a basic nitrogen and oxygen emission preset by the vehicle;
and the control module is used for taking the product of the basic injection quantity and the control coefficient as an actual injection quantity, and controlling the SCR system to inject the urea solution according to the actual injection quantity, wherein the basic injection quantity is determined according to the basic nitrogen and oxygen emission quantity and the working parameters.
Optionally, the apparatus further comprises: a second determination module;
the second determination module is used for determining the conversion efficiency of the SCR system and the ammonia storage amount of the SCR system according to the working parameters before the actual nitrogen and oxygen emission amount measured by the nitrogen and oxygen sensor is obtained, and determining the basic injection amount according to a preset ammonia-nitrogen ratio, the basic nitrogen and oxygen emission amount, the conversion efficiency and the ammonia storage amount;
the second determination module is further used for determining the target nitrogen and oxygen emission amount according to the basic nitrogen and oxygen emission amount.
Optionally, the first determining module includes:
the judgment submodule is used for determining that the working parameters and the SCR system both meet the control conditions if the working parameters belong to the normal parameter range and the working state of the SCR system is a normal state;
the determining submodule is used for determining target correction time and target correction step length according to the working parameters;
and the obtaining submodule is used for taking the emission deviation, the target correction time and the target correction step length as the input of a preset proportional-integral controller so as to obtain the control coefficient output by the proportional-integral controller.
Optionally, the operating parameters include: temperature, pressure, and exhaust flow, the determination submodule to:
determining initial correction time and the target correction step length according to the temperature and the exhaust flow;
determining an environment correction value and a working boundary correction value of the SCR system according to the temperature and the pressure;
and taking the product of the initial correction time, the environment correction value and the working boundary correction value as the target correction time.
Optionally, the apparatus further comprises:
and the first resetting module is used for setting the control coefficient as a preset initial control coefficient if the control coefficient is greater than or equal to a first coefficient threshold value or the control coefficient is smaller than a second coefficient threshold value after the control coefficient is determined according to the working parameter and the emission deviation if the working parameter at the current moment and the SCR system both meet the control condition, wherein the first coefficient threshold value is greater than the second coefficient threshold value.
Optionally, the apparatus further comprises:
and the second resetting module is used for determining that the SCR system is in an ammonia leakage state and setting the control coefficient as a preset initial control coefficient if the emission deviation is greater than the emission deviation at the previous moment and the control coefficient is greater than the control coefficient at the previous moment after the working parameter at the current moment and the SCR system both meet the control condition and the control coefficient is determined according to the working parameter and the emission deviation.
According to the technical scheme, the method comprises the steps of firstly obtaining actual nitrogen and oxygen discharge amount measured by a nitrogen and oxygen sensor arranged at the downstream of an SCR system in real time, determining a control coefficient according to working parameters and discharge amount deviation on the premise that the working parameters and the SCR system meet control conditions, and finally taking the product of basic injection amount and the control coefficient as actual injection amount and controlling the SCR system to inject urea solution according to the actual injection amount, wherein the target nitrogen and oxygen discharge amount is determined according to basic nitrogen and oxygen discharge amount preset by a vehicle, and the basic injection amount is determined according to the basic nitrogen and oxygen discharge amount and the working parameters. According to the method, the injection quantity of the SCR system is adjusted in real time according to the actual nitrogen and oxygen emission quantity of the downstream of the SCR system, the injection quantity can meet the conversion requirement in the scenes of aging of the SCR system, unstable external environment and the like, and the accuracy and the adaptability of the SCR system are improved.
Additional features and advantages of the disclosure will be set forth in the detailed description which follows.
Drawings
The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and together with the description serve to explain the disclosure without limiting the disclosure. In the drawings:
FIG. 1 is a flowchart illustrating a control method for injecting urea according to an exemplary embodiment;
FIG. 2 is a flowchart illustrating another control method for injecting urea according to an exemplary embodiment;
FIG. 3 is a flowchart illustrating another control method for injecting urea according to an exemplary embodiment;
FIG. 4 is a flowchart illustrating another control method for injecting urea according to an exemplary embodiment;
FIG. 5 is a flowchart illustrating another control method for injecting urea according to an exemplary embodiment;
FIG. 6 is a block diagram illustrating a control device for injecting urea in accordance with an exemplary embodiment;
FIG. 7 is a block diagram of another control apparatus for injecting urea, according to an exemplary embodiment;
FIG. 8 is a block diagram of another control apparatus for injecting urea according to an exemplary embodiment;
FIG. 9 is a block diagram of another control apparatus for injecting urea, according to an exemplary embodiment;
FIG. 10 is a block diagram illustrating another control apparatus for injecting urea according to an exemplary embodiment.
Detailed Description
Reference will now be made in detail to the exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, like numbers in different drawings represent the same or similar elements unless otherwise indicated. The implementations described in the exemplary embodiments below are not intended to represent all implementations consistent with the present disclosure. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present disclosure, as detailed in the appended claims.
Before describing the method and apparatus for controlling urea injection provided by the present disclosure, an application scenario related to various embodiments of the present disclosure will be described. The application scenario may be a vehicle using a diesel engine, the outlet of which is provided with an SCR system. The vehicle may be a transportation vehicle, a construction vehicle, an automobile, etc., and the disclosure is not limited thereto.
FIG. 1 is a flowchart illustrating a control method for injecting urea, as shown in FIG. 1, for a vehicle having a Selective Catalytic Reduction (SCR) system disposed thereon, according to an exemplary embodiment, including the steps of:
and 101, acquiring the actual nitrogen and oxygen emission amount measured by a nitrogen and oxygen sensor, wherein the nitrogen and oxygen sensor is arranged at the downstream of the SCR system.
For example, when a vehicle leaves a factory, a base nitrogen and oxygen emission amount (which may be in mg/s) of a diesel engine is calibrated, that is, the emission amount of nitrogen oxides in a gas emitted from an exhaust port of the diesel engine is calibrated, and the emission amount of nitrogen oxides input to an SCR system is also calibrated, and the base nitrogen and oxygen emission amount is also referred to as an upstream nitrogen and oxygen emission amount or an original nitrogen and oxygen emission amount. Accordingly, a target nox emission amount (also referred to as a downstream nox emission amount) corresponding to the base nox emission amount can be determined in accordance with a prescribed emission standard. Further, the basic injection quantity of the SCR system can be determined according to the basic nitrogen and oxygen emission quantity and the current working parameters. The basic injection quantity is understood to mean the injection quantity of the urea solution required for the SCR system to reduce nitrogen oxides, indicated by the basic nitrogen and oxygen emission, to nitrogen and water under ideal operating conditions.
Because of the deviation of the consistency of the vehicle and the diesel engine and other parts during assembly, the basic nitrogen and oxygen discharge amount may be different from the actual nitrogen and oxygen discharge amount discharged by the diesel engine. Also, as the SCR system ages over time, the conversion efficiency of nitrogen oxides to nitrogen and water decreases. Meanwhile, the concentration of the urea solution injected by the SCR system also has certain deviation. If the SCR system is directly controlled to inject the urea solution according to the basic injection quantity, the problem that the actual nitrogen and oxygen emission quantity cannot be reduced to be below the emission standard due to too little urea solution injection or the problem that the urea is crystallized due to too much urea solution injection may occur, and further, the false alarm of an OBD (On-Board Diagnostics, Chinese) system arranged On a vehicle may be caused. Therefore, the reduction of nitrogen oxides by the SCR system needs to be monitored in real time to adjust the injection amount of the SCR system. The actual nitrogen and oxygen discharge amount of the downstream of the SCR system can be collected in real time through a nitrogen and oxygen sensor arranged on the downstream of the SCR system, and the actual nitrogen and oxygen discharge amount and the target nitrogen and oxygen discharge amount are compared to be used as a standard for judging whether the injection amount of the SCR system needs to be adjusted.
And 102, if the working parameters at the current moment and the SCR system both meet the control conditions, determining a control coefficient according to the working parameters and the emission deviation, wherein the emission deviation is the difference between the actual nitrogen and oxygen emission and the target nitrogen and oxygen emission, and the target nitrogen and oxygen emission is determined according to the basic nitrogen and oxygen emission preset by the vehicle.
And 103, taking the product of the basic injection quantity and the control coefficient as an actual injection quantity, and controlling the SCR system to inject the urea solution according to the actual injection quantity, wherein the basic injection quantity is determined according to the basic nitrogen and oxygen emission quantity and the working parameters.
For example, before determining whether the injection amount of the SCR system needs to be adjusted, it may be further determined whether the SCR system is currently suitable for adjusting the injection amount, that is, whether the operating parameters at the current time, such as temperature, pressure, exhaust flow and other parameters affecting the operation of the SCR system, and the SCR system meet the control conditions. Wherein, the control conditions may include, but are not limited to, the following examples: the operating state of the SCR system is a normal state, an FBC-NOx (Fuel Catalyst-Nitrogen Oxides, chinese) controller has been activated, a Nitrogen oxygen sensor has been activated, the injection state of the SCR system is normal, the temperature in the operating parameters belongs to the normal operating temperature of the SCR system, etc.
If the working parameters and the SCR system meet the control conditions, the emission deviation can be determined according to the difference value between the actual nitrogen and oxygen emission and the target nitrogen and oxygen emission, and then the control coefficient is determined according to the emission deviation and the working parameters. If the operating parameter or the SCR system does not satisfy the control condition, which indicates that the SCR system is currently not suitable for adjusting the injection quantity, the control coefficient may be set to 1, and the actual injection quantity is equal to the base injection quantity, i.e. the SCR system injects the urea solution according to the base injection quantity. And finally, taking the product of the basic injection quantity and the control coefficient as an actual injection quantity, and controlling the SCR system to inject the urea solution according to the actual injection quantity.
It can be understood that if the actual nitrogen and oxygen emission amount is larger than the target nitrogen and oxygen emission amount, that is, the emission amount deviation is a positive value, which indicates that the urea solution is injected too little and the actual nitrogen and oxygen emission amount cannot be reduced below the emission standard, the control coefficient can be increased to achieve the purpose of increasing the actual injection amount of the urea solution. If the actual nitrogen and oxygen discharge amount is smaller than the target nitrogen and oxygen discharge amount, namely the discharge amount deviation is a negative value, which indicates that the urea solution is injected too much and urea crystallization is likely to be caused, the control coefficient can be reduced so as to achieve the purpose of reducing the actual injection amount of the urea solution. By repeatedly performing steps 101 to 103, the actual amount of nitrogen and oxygen emissions downstream of the SCR system can be stabilized within the range of emission standards. Therefore, according to the actual nitrogen and oxygen discharge amount of the downstream of the SCR system, the actual injection amount of the SCR system can be adjusted in real time, and in the scenes of ageing of the SCR system, deviation of the assembly consistency of a diesel engine, inaccurate concentration of urea solution and the like, the actual injection amount can meet the conversion requirement of nitrogen oxides and is not too high, so that urea crystallization is caused, and the accuracy and the adaptability of the SCR system can be improved. Furthermore, the false alarm of the OBD system can be avoided. The actual injection amount may be the injection amount of ammonia gas or the injection amount of urea solution. When the actual injection amount is the injection amount of ammonia, when specifically controlling the SCR system to inject the urea solution according to the actual injection amount, it is also necessary to multiply a preset proportionality coefficient (for example, 5.425) on the basis of the actual injection amount to convert the injection amount of ammonia into the injection amount of urea solution.
In summary, the present disclosure first obtains an actual nox emission measured by a nox sensor disposed downstream of an SCR system in real time, determines a control coefficient according to a deviation between a working parameter and the emission on the premise that the working parameter and the SCR system both satisfy a control condition, and finally takes a product of a basic injection amount and the control coefficient as an actual injection amount, and controls the SCR system to inject a urea solution according to the actual injection amount, wherein a target nox emission is determined according to a basic nox emission preset by a vehicle, and the basic injection amount is determined according to the basic nox emission and the working parameter. According to the method, the injection quantity of the SCR system is adjusted in real time according to the actual nitrogen and oxygen emission quantity of the downstream of the SCR system, the injection quantity can meet the conversion requirement in the scenes of aging of the SCR system, unstable external environment and the like, and the accuracy and the adaptability of the SCR system are improved.
FIG. 2 is a flow chart illustrating another control method for injecting urea according to an exemplary embodiment, as shown in FIG. 2, before step 101, the method further comprising:
and 104, determining the conversion efficiency of the SCR system and the ammonia storage amount of the SCR system according to the working parameters, and determining the basic injection amount according to the preset ammonia-nitrogen ratio, the basic nitrogen-oxygen emission amount, the conversion efficiency and the ammonia storage amount.
In a specific application scenario, the basic injection amount is related to a preset ammonia nitrogen ratio, the conversion efficiency of the SCR system and the ammonia storage amount of the SCR system. The ammonia nitrogen ratio can be understood as the ratio of ammonia element to nitrogen element in the reduction reaction in the SCR system, and is a preset parameter, and the conversion efficiency (which can be understood as the efficiency of the SCR system for converting nitrogen oxide into nitrogen gas) and the ammonia storage amount (which can be understood as the content of ammonia gas stored in the SCR system during operation) are both related to the operating parameters, so that the conversion efficiency and the ammonia storage amount can be determined according to the operating parameters. Specifically, a conversion efficiency model or a conversion efficiency table may be pre-established according to a large amount of experimental data at the stage of designing and developing the SCR system, where the conversion efficiency of the SCR system under different operating parameters is included, for example, the SCR system may be quickly aged, then the SCR system is placed under different operating parameter conditions to operate, and the conversion efficiency corresponding to different operating parameters is obtained through measurement. Then the conversion efficiency corresponding to the operating parameter at the current time may be determined. Similarly, an ammonia storage model or an ammonia storage table may be pre-established, wherein the ammonia storage amounts of the SCR system under different operating parameters are included, so that the ammonia storage amount corresponding to the operating parameter at the current time may be determined. And finally, determining the basic injection quantity according to the ammonia-nitrogen ratio, the basic nitrogen-oxygen discharge quantity, the conversion efficiency and the ammonia storage quantity.
Taking the example of the working parameters including the temperature, the temperature is proportional to the conversion efficiency within a certain range, that is, the higher the temperature is, the higher the conversion efficiency is, the less ammonia is needed for converting the same mass of nitrogen oxides, and the corresponding basic emission injection amount is reduced, and conversely, the lower the temperature is, the lower the conversion efficiency is, the more ammonia is needed for converting the same mass of nitrogen oxides, and the corresponding basic emission injection amount is increased. Meanwhile, the temperature is inversely proportional to the ammonia storage amount, namely the higher the temperature is, the lower the ammonia storage amount is, the ammonia gas stored in the SCR system can be released, and the ammonia gas is obtained by injecting the urea solution, so that the total amount of the ammonia gas can be increased, and the basic injection amount can be reduced.
And step 105, determining the target nitrogen and oxygen emission amount according to the basic nitrogen and oxygen emission amount.
Accordingly, the target NOx emission amount is related to the base NOx emission amount, and the target NOx emission amount (also referred to as a downstream NOx emission amount) corresponding to the base NOx emission amount can be determined according to a predetermined emission standard (for example, the national 5 standard, the national 6 standard, and the like). Wherein, can be in the design research and development stage through a large amount of experimental data, establish basic nitrogen and oxygen and discharge the model with the target nitrogen and oxygen that basic nitrogen and oxygen discharged the model and correspond, like this, at the vehicle driving in-process, can be according to the different operating condition and the different operational environment of vehicle, confirm basic nitrogen and oxygen emission and target nitrogen and oxygen emission.
FIG. 3 is a flowchart illustrating another control method for injecting urea according to an exemplary embodiment, as shown in FIG. 3, step 102 includes:
and 1021, if the working parameters belong to the normal parameter range and the working state of the SCR system is a normal state, determining that the working parameters and the SCR system both meet the control conditions.
The working parameters comprise: temperature, pressure, and exhaust flow, for example, wherein temperature may include: the temperature inside the SCR system may also include the outside temperature, the pressure may include the gas pressure in the operating environment of the SCR system, etc., and the exhaust gas flow rate may be understood as the flow rate of gas emitted by a diesel engine after burning diesel. Correspondingly, the normal parameter range can be divided into a temperature range, a pressure range and an exhaust flow range, and when the temperature, the pressure and the exhaust flow respectively meet the temperature range, the pressure range and the exhaust flow range, the working parameter is determined to belong to the normal parameter range. Further, the working state of the SCR system can be determined, and when the working state of the SCR system is a normal state and the working parameter belongs to a normal parameter range, the working parameter and the SCR system can both meet the control condition. If the operating parameter does not fall within the normal parameter range or the operating state of the SCR system is not normal (e.g., in a sleep state, an abnormal state, etc.), indicating that the SCR system is currently not suitable for adjusting the injection quantity, the control coefficient may be set to 1, i.e., the actual injection quantity is equal to the base injection quantity.
And step 1022, determining a target correction time and a target correction step length according to the working parameters.
And step 1023, taking the emission deviation, the target correction time and the target correction step length as the input of a preset proportional-integral controller to obtain a control coefficient output by the proportional-integral controller.
For example, a (english: probability Integral Controller) may be preset to determine the control coefficient, and the Proportional Integral Controller includes a Proportional adjustment portion and an Integral adjustment portion for correcting a deviation between the actual output value (i.e., the actual amount of nitrogen and oxygen discharged) and the target output value (i.e., the target amount of nitrogen and oxygen discharged). In order to control the proportional-integral controller to adjust the time and step length of the deviation, a target correction time and a target correction step length may be determined from the operating parameters, wherein the target correction step length reflects the span of control coefficient adjustment and the target correction time reflects the duration of the integral of the emission deviation.
Specifically, the initial correction time and the target correction step may be determined according to the temperature and the exhaust flow rate in the operating parameters. The initial correction time may be determined by the correspondence between the initial correction time and the temperature, the exhaust flow rate, and similarly, the target correction step may be determined by the correspondence between the target correction step and the temperature, the exhaust flow rate. Furthermore, an environment correction value and an operation boundary correction value of the SCR system are determined according to the temperature and the pressure. And finally, taking the product of the initial correction time, the environment correction value and the working boundary correction value as the target correction time.
The target correction step length and the target correction time are in a corresponding relation with the working parameter, for example, the temperature in the working parameter is taken as an example, the target correction step length and the temperature may be in a positive correlation, and the target correction time and the temperature may be in a negative correlation, that is, the higher the temperature is, the longer the target correction step length is, and the shorter the target correction time is. It will be appreciated that the higher the temperature, the more severe the reduction reaction in the SCR system, and the faster the control coefficient adjustment is required, i.e. the greater the span of adjustment required for the control coefficient, the shorter the duration of integration of the emission deviation. Correspondingly, the lower the temperature, the slower the reduction reaction in the SCR system, and the slower the control coefficient can be adjusted, i.e. the smaller the span over which the control coefficient needs to be adjusted, the longer the duration of the integration of the emission deviation.
And after the target correction time and the target correction step length are determined, the emission deviation, the target correction time and the target correction step length are used as the input of a preset proportional-integral controller to obtain a control coefficient output by the proportional-integral controller. It is understood that the discharge amount deviation is taken as a deviation amount of the proportional-integral controller, the target correction step is taken as a proportional step of a proportional adjustment part in the proportional-integral controller, and the target correction time is taken as an integral duration of an integral adjustment part in the proportional-integral controller, so that the proportional-integral controller keeps outputting a control coefficient within the target correction duration, and the control coefficient is different from a historical control coefficient output by the proportional-integral controller before the last target correction duration by the target correction step. For example, the actual nitrogen and oxygen emission is higher than the target nitrogen and oxygen emission, the control coefficient output by the proportional-integral controller at the current moment is 1.09, the control coefficient needs to be adjusted to 1.15 to meet the emission standard, the target correction time is determined to be 5min according to the working parameters at the current moment, the target correction step length is 0.01, the proportional-integral controller increases the output control coefficient to 1.10 and keeps outputting 1.10 within 5min, if the working parameters are kept unchanged in the adjustment process (namely the target correction time is kept to be 5min, and the target correction step length is kept to be 0.01), the steps 101 to 103 are repeatedly executed, the control coefficient can be adjusted to 1.15 after 6 times (namely 30 min),
the emission amount deviation is a difference between the actual nitrogen and oxygen emission amounts and the target nitrogen and oxygen emission amounts, and may be expressed in ppm, and the emission amount deviation may be converted into a deviation control parameter of the proportional-integral controller before being input to the proportional-integral controller. The emissions deviation can be converted first into a flow mass (in mg/s), i.e. a flow mass (emissions deviation) exhaust flow (exhaust flow) molar mass (nox emission) conversion factor, wherein the conversion factor can be 277.78/1000000. And then, searching the deviation control parameters corresponding to the flow quality in a table look-up mode. And finally, taking the deviation control parameter as the deviation amount of the proportional-integral controller.
FIG. 4 is a flowchart illustrating another control method for injecting urea according to an exemplary embodiment, as shown in FIG. 4, after step 102, the method may further include:
and 106, if the control coefficient is greater than or equal to the first coefficient threshold value or the control coefficient is smaller than the second coefficient threshold value, setting the control coefficient as a preset initial control coefficient, wherein the first coefficient threshold value is greater than the second coefficient threshold value.
For example, in order to avoid that the actual injection amount is too high to cause urea crystallization, or too low to cause the actual nitrogen and oxygen emission amount to not meet the emission standard, an upper limit of the control coefficient, i.e., a first coefficient threshold (which may be 1.2, for example), and a lower limit of the control coefficient, i.e., a second coefficient threshold (which may be 0.8, for example) may be set. When the control coefficient is greater than or equal to the first coefficient threshold, which indicates that the control coefficient has exceeded the upper limit and the actual injection amount is too high, the control coefficient may be set to a preset initial control coefficient (which may be 1, for example). When the control coefficient is smaller than the second coefficient threshold, it indicates that the control coefficient is lower than the lower limit, and the actual injection amount is too low, then the control coefficient may also be set as the initial control coefficient. Further, in order to ensure the stability of the SCR system, the control coefficient may be obtained within a period of time (for example, 1900s), and if the control coefficient is always greater than or equal to the first coefficient threshold (or always less than the second coefficient threshold) within the period of time, the control coefficient is set as the initial control coefficient.
FIG. 5 is a flowchart illustrating another control method for injecting urea according to an exemplary embodiment, as shown in FIG. 5, after step 102, the method may further include:
and 107, if the emission deviation is larger than the emission deviation at the previous moment and the control coefficient is larger than the control coefficient at the previous moment, determining that the SCR system is in an ammonia leakage state, and setting the control coefficient as a preset initial control coefficient.
For example, since the SCR system may have an ammonia slip problem, that is, the actual nitrogen and oxygen emission measured by the nitrogen and oxygen sensor may include ammonia, the actual nitrogen and oxygen emission measured in step 101 is always increased, and the control coefficient determined in step 102 is also always increased, which results in an actual injection amount being too high, so that in order to avoid urea crystallization caused by the actual injection amount being too high, the control coefficient may be set to a preset initial control coefficient (which may be 1, for example) when the SCR system is determined to be in an ammonia slip state. For example, whether or not the problem of ammonia slip has occurred may be determined by comparing the relationship between the control coefficient output by the proportional-integral controller at the present time and the control coefficient at the previous time, and comparing the relationship between the emission amount deviation at the present time and the emission amount deviation at the previous time.
Specifically, if ammonia leakage does not occur, under normal conditions, if the control coefficient at the current time is greater than the control coefficient at the previous time, it indicates that the actual injection amount of the SCR system at the current time is a trend of increasing, and the corresponding emission amount deviation should be reduced, that is, the emission amount deviation at the current time should be smaller than the emission amount deviation at the previous time. If ammonia leakage occurs, in a scene that the control coefficient at the current moment is larger than that at the previous moment, it indicates that the actual injection amount of the SCR system at the current moment is a trend of increasing, the corresponding emission amount deviation should be reduced, and due to the ammonia leakage, the emission amount deviation at the current moment still increases, that is, the emission amount deviation at the current moment is larger than that at the previous moment. At this time, it may be determined that the SCR system is in an ammonia slip state, and further, the control coefficient may be set to a preset initial control coefficient.
It should be noted that the control method for injecting urea provided by the present disclosure may also be verified by means of manual testing. For example, the urea solution may be blended with water to reduce the concentration of the urea solution from 32.5% to below 28%, and then the SCR system starts to operate under different operating conditions (e.g., cold cycle or hot cycle), and after performing steps 101 to 103 for a plurality of times (e.g., 9 to 10 times), the actual amount of nitrogen and oxygen discharged downstream of the SCR system can meet the emission standard.
In summary, the present disclosure first obtains an actual nox emission measured by a nox sensor disposed downstream of an SCR system in real time, determines a control coefficient according to a deviation between a working parameter and the emission on the premise that the working parameter and the SCR system both satisfy a control condition, and finally takes a product of a basic injection amount and the control coefficient as an actual injection amount, and controls the SCR system to inject a urea solution according to the actual injection amount, wherein a target nox emission is determined according to a basic nox emission preset by a vehicle, and the basic injection amount is determined according to the basic nox emission and the working parameter. According to the method, the injection quantity of the SCR system is adjusted in real time according to the actual nitrogen and oxygen emission quantity of the downstream of the SCR system, the injection quantity can meet the conversion requirement in the scenes of aging of the SCR system, unstable external environment and the like, and the accuracy and the adaptability of the SCR system are improved.
Fig. 6 is a block diagram illustrating a control apparatus for injecting urea according to an exemplary embodiment, and as shown in fig. 6, the apparatus 200 is applied to a vehicle on which a selective catalytic reduction SCR system is provided, and the apparatus 200 includes:
an obtaining module 201 is configured to obtain an actual amount of nitrogen and oxygen discharged from a nitrogen and oxygen sensor, where the nitrogen and oxygen sensor is disposed downstream of the SCR system.
The first determining module 202 is configured to determine a control coefficient according to a working parameter and an emission deviation if the working parameter and the SCR system at the current time both meet a control condition, where the emission deviation is a difference between an actual nitrogen and oxygen emission and a target nitrogen and oxygen emission, and the target nitrogen and oxygen emission is determined according to a basic nitrogen and oxygen emission preset by a vehicle.
And the control module 203 is used for taking the product of the basic injection quantity and the control coefficient as an actual injection quantity and controlling the SCR system to inject the urea solution according to the actual injection quantity, wherein the basic injection quantity is determined according to the basic nitrogen and oxygen emission quantity and the working parameters.
Fig. 7 is a block diagram illustrating a control apparatus for injecting urea according to an exemplary embodiment, and as shown in fig. 7, the apparatus 200 further includes:
and the second determination module 204 is used for determining the conversion efficiency of the SCR system and the ammonia storage amount of the SCR system according to the working parameters, and determining the basic injection amount according to the preset ammonia-nitrogen ratio, the basic nitrogen-oxygen emission amount, the conversion efficiency and the ammonia storage amount.
The second determination module 204 is further configured to determine a target NOx emission based on the base NOx emission.
FIG. 8 is a block diagram illustrating another control apparatus for injecting urea according to an exemplary embodiment, where, as shown in FIG. 8, the first determination module 202 includes:
the determining sub-module 2021 is configured to determine that the operating parameter and the SCR system both satisfy the control condition if the operating parameter belongs to the normal parameter range and the operating state of the SCR system is a normal state.
The determining sub-module 2022 is configured to determine a target correction time and a target correction step size according to the operating parameters.
The obtaining sub-module 2023 is configured to use the emission deviation, the target correction time, and the target correction step as inputs of a preset proportional-integral controller to obtain a control coefficient output by the proportional-integral controller.
Optionally, the operating parameters include: temperature, pressure and exhaust flow, the determination submodule 2022 is configured to perform the steps of:
first, an initial correction time and a target correction step size are determined according to the temperature and the exhaust flow rate among the operating parameters.
And then determining an environment correction value and an operation boundary correction value of the SCR system according to the temperature and the pressure.
And finally, taking the product of the initial correction time, the environment correction value and the working boundary correction value as the target correction time.
Fig. 9 is a block diagram illustrating another control apparatus for injecting urea according to an exemplary embodiment, and as shown in fig. 9, the apparatus 200 further includes:
the first resetting module 205 is configured to, after determining the control coefficient according to the deviation of the operating parameter and the emission amount if the operating parameter at the current time and the SCR system both satisfy the control condition, set the control coefficient as a preset initial control coefficient if the control coefficient is greater than or equal to a first coefficient threshold, or the control coefficient is smaller than a second coefficient threshold, where the first coefficient threshold is greater than the second coefficient threshold.
Fig. 10 is a block diagram illustrating another control apparatus for injecting urea according to an exemplary embodiment, and as shown in fig. 10, the apparatus 200 further includes:
and the second resetting module 206 is configured to determine that the SCR system is in an ammonia leakage state if the emission deviation is greater than the emission deviation at the previous time and the control coefficient is greater than the control coefficient at the previous time after determining the control coefficient according to the operating parameter and the emission deviation if the operating parameter at the current time and the SCR system both satisfy the control condition, and set the control coefficient to a preset initial control coefficient.
In summary, the present disclosure first obtains an actual nox emission measured by a nox sensor disposed downstream of an SCR system in real time, determines a control coefficient according to a deviation between a working parameter and the emission on the premise that the working parameter and the SCR system both satisfy a control condition, and finally takes a product of a basic injection amount and the control coefficient as an actual injection amount, and controls the SCR system to inject a urea solution according to the actual injection amount, wherein a target nox emission is determined according to a basic nox emission preset by a vehicle, and the basic injection amount is determined according to the basic nox emission and the working parameter. According to the method, the injection quantity of the SCR system is adjusted in real time according to the actual nitrogen and oxygen emission quantity of the downstream of the SCR system, the injection quantity can meet the conversion requirement in the scenes of aging of the SCR system, unstable external environment and the like, and the accuracy and the adaptability of the SCR system are improved.
The preferred embodiments of the present disclosure are described in detail with reference to the accompanying drawings, however, the present disclosure is not limited to the specific details of the above embodiments, and various simple modifications may be made to the technical solution of the present disclosure within the technical idea of the present disclosure, and these simple modifications all belong to the protection scope of the present disclosure.
It should be noted that, in the foregoing embodiments, various features described in the above embodiments may be combined in any suitable manner, and in order to avoid unnecessary repetition, various combinations that are possible in the present disclosure are not described again.
In addition, any combination of various embodiments of the present disclosure may be made, and the same should be considered as the disclosure of the present disclosure, as long as it does not depart from the spirit of the present disclosure.

Claims (10)

1. A control method for injecting urea is applied to a vehicle, and the vehicle is provided with a Selective Catalytic Reduction (SCR) system, and the method comprises the following steps:
acquiring actual nitrogen and oxygen emission measured by a nitrogen and oxygen sensor, wherein the nitrogen and oxygen sensor is arranged at the downstream of the SCR system;
if the working parameters at the current moment and the SCR system both meet the control conditions, determining a control coefficient according to the working parameters and the emission deviation, wherein the emission deviation is the difference value between the actual nitrogen and oxygen emission and the target nitrogen and oxygen emission, and the target nitrogen and oxygen emission is determined according to the basic nitrogen and oxygen emission preset by the vehicle;
taking the product of the basic injection quantity and the control coefficient as an actual injection quantity, and controlling the SCR system to inject urea solution according to the actual injection quantity, wherein the basic injection quantity is determined according to the basic nitrogen and oxygen emission quantity and the working parameters;
after determining a control coefficient according to the working parameter and the emission deviation if the working parameter at the current moment and the SCR system both meet the control condition, the method further comprises:
if the control coefficient is larger than or equal to a first coefficient threshold value, or the control coefficient is smaller than a second coefficient threshold value, setting the control coefficient as a preset initial control coefficient, wherein the first coefficient threshold value is larger than the second coefficient threshold value.
2. The method of claim 1, wherein prior to said obtaining actual NOx emissions measured by a NOx sensor, the method further comprises:
determining the conversion efficiency of the SCR system and the ammonia storage amount of the SCR system according to the working parameters, and determining the basic injection amount according to a preset ammonia-nitrogen ratio, the basic nitrogen-oxygen emission amount, the conversion efficiency and the ammonia storage amount;
and determining the target nitrogen and oxygen emission according to the basic nitrogen and oxygen emission.
3. The method of claim 1, wherein determining a control coefficient according to the operating parameter and the emission deviation if the operating parameter at the current time and the SCR system both satisfy a control condition comprises:
if the working parameters belong to the normal parameter range and the working state of the SCR system is a normal state, determining that the working parameters and the SCR system both meet the control conditions;
determining target correction time and target correction step length according to the working parameters;
and taking the emission deviation, the target correction time and the target correction step length as the input of a preset proportional-integral controller to obtain the control coefficient output by the proportional-integral controller.
4. The method of claim 3, wherein the operating parameters comprise: the determining of the target correction time and the target correction step length according to the operating parameters comprises the following steps:
determining initial correction time and the target correction step length according to the temperature and the exhaust flow;
determining an environment correction value and a working boundary correction value of the SCR system according to the temperature and the pressure;
and taking the product of the initial correction time, the environment correction value and the working boundary correction value as the target correction time.
5. The method according to any one of claims 1-4, wherein after determining the control coefficient according to the operating parameter and the emission deviation if the operating parameter at the current time and the SCR system both satisfy the control condition, the method further comprises:
and if the emission deviation is larger than the emission deviation at the previous moment and the control coefficient is larger than the control coefficient at the previous moment, determining that the SCR system is in an ammonia leakage state, and setting the control coefficient as a preset initial control coefficient.
6. A control device for injecting urea, applied to a vehicle on which a Selective Catalytic Reduction (SCR) system is provided, the device comprising:
the acquisition module is used for acquiring the actual nitrogen and oxygen emission amount measured by a nitrogen and oxygen sensor, and the nitrogen and oxygen sensor is arranged at the downstream of the SCR system;
the first determining module is used for determining a control coefficient according to the working parameters and emission deviation if the working parameters at the current moment and the SCR system both meet control conditions, wherein the emission deviation is a difference value between the actual nitrogen and oxygen emission and a target nitrogen and oxygen emission, and the target nitrogen and oxygen emission is determined according to a basic nitrogen and oxygen emission preset by the vehicle;
the control module is used for taking the product of the basic injection quantity and the control coefficient as an actual injection quantity and controlling the SCR system to inject the urea solution according to the actual injection quantity, wherein the basic injection quantity is determined according to the basic nitrogen and oxygen emission quantity and the working parameters;
the device further comprises:
and the first resetting module is used for setting the control coefficient as a preset initial control coefficient if the control coefficient is greater than or equal to a first coefficient threshold value or the control coefficient is smaller than a second coefficient threshold value after the control coefficient is determined according to the working parameter and the emission deviation if the working parameter at the current moment and the SCR system both meet the control condition, wherein the first coefficient threshold value is greater than the second coefficient threshold value.
7. The apparatus of claim 6, further comprising: a second determination module;
the second determination module is used for determining the conversion efficiency of the SCR system and the ammonia storage amount of the SCR system according to the working parameters before the actual nitrogen and oxygen emission amount measured by the nitrogen and oxygen sensor is obtained, and determining the basic injection amount according to a preset ammonia-nitrogen ratio, the basic nitrogen and oxygen emission amount, the conversion efficiency and the ammonia storage amount;
the second determination module is further used for determining the target nitrogen and oxygen emission amount according to the basic nitrogen and oxygen emission amount.
8. The apparatus of claim 6, wherein the first determining module comprises:
the judgment submodule is used for determining that the working parameters and the SCR system both meet the control conditions if the working parameters belong to the normal parameter range and the working state of the SCR system is a normal state;
the determining submodule is used for determining target correction time and target correction step length according to the working parameters;
and the obtaining submodule is used for taking the emission deviation, the target correction time and the target correction step length as the input of a preset proportional-integral controller so as to obtain the control coefficient output by the proportional-integral controller.
9. The apparatus of claim 8, wherein the operating parameters comprise: temperature, pressure, and exhaust flow, the determination submodule to:
determining initial correction time and the target correction step length according to the temperature and the exhaust flow;
determining an environment correction value and a working boundary correction value of the SCR system according to the temperature and the pressure;
and multiplying the initial correction time by the environment correction value and the working boundary correction value to obtain the target correction time.
10. The apparatus according to any one of claims 6-9, further comprising:
and the second resetting module is used for determining that the SCR system is in an ammonia leakage state and setting the control coefficient as a preset initial control coefficient if the emission deviation is greater than the emission deviation at the previous moment and the control coefficient is greater than the control coefficient at the previous moment after the working parameter at the current moment and the SCR system both meet the control condition and the control coefficient is determined according to the working parameter and the emission deviation.
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