CN119102845B - Double-stage SCR urea injection quantity control method, device and equipment - Google Patents
Double-stage SCR urea injection quantity control method, device and equipmentInfo
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- CN119102845B CN119102845B CN202411385074.1A CN202411385074A CN119102845B CN 119102845 B CN119102845 B CN 119102845B CN 202411385074 A CN202411385074 A CN 202411385074A CN 119102845 B CN119102845 B CN 119102845B
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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
- F01N9/00—Electrical control of exhaust gas treating apparatus
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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
- F01N3/206—Adding periodically or continuously substances to exhaust gases for promoting purification, e.g. catalytic material in liquid form, NOx reducing agents
- F01N3/208—Control of selective catalytic reduction [SCR], e.g. by adjusting the dosing of reducing agent
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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
- F01N2610/00—Adding substances to exhaust gases
- F01N2610/02—Adding substances to exhaust gases the substance being ammonia or urea
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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
- F01N2900/00—Details of electrical control or of the monitoring of the exhaust gas treating apparatus
- F01N2900/06—Parameters used for exhaust control or diagnosing
- F01N2900/18—Parameters used for exhaust control or diagnosing said parameters being related to the system for adding a substance into the exhaust
- F01N2900/1806—Properties of reducing agent or dosing system
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- 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
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- Chemical Kinetics & Catalysis (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Health & Medical Sciences (AREA)
- Toxicology (AREA)
- Exhaust Gas After Treatment (AREA)
Abstract
本发明公开了一种双级SCR尿素喷射量控制方法、装置及设备，涉及发动机排气后处理技术领域，该方法包括获取发动机的实时工作模式，并根据获取的工作模式确定前级SCR和后级SCR的控制模式；基于确定的控制模式，前级SCR和后级SCR进行对应尿素喷射量计算，并根据SCR的工作状态进行控制模式切换；其中，前级SCR的控制模式包括初始模式、目标效率模式、高效率模式，后级SCR的控制模式包括初始模式、高效率模式。本申请通过根据发动机工作模式确定双级SCR的协调控制状态，针对不同工作模式更有效的降低氮氧化物排放，同时还考虑DPF状态对双级SCR协调控制的影响，实现对双级SCR的尿素喷射量的高效协调控制。
The present invention discloses a dual-stage SCR urea injection quantity control method, device and equipment, relating to the technical field of engine exhaust aftertreatment. The method comprises obtaining the real-time operating mode of the engine and determining the control mode of the front-stage SCR and the rear-stage SCR according to the obtained operating mode; based on the determined control mode, the front-stage SCR and the rear-stage SCR perform corresponding urea injection quantity calculations, and switch the control mode according to the operating state of the SCR; wherein the control mode of the front-stage SCR includes an initial mode, a target efficiency mode, and a high-efficiency mode, and the control mode of the rear-stage SCR includes an initial mode and a high-efficiency mode. The present application determines the coordinated control state of the dual-stage SCR according to the engine operating mode, more effectively reduces nitrogen oxide emissions for different operating modes, and also considers the influence of the DPF state on the coordinated control of the dual-stage SCR, thereby achieving efficient coordinated control of the urea injection quantity of the dual-stage SCR.
Description
Technical Field
The application relates to the technical field of engine exhaust aftertreatment, in particular to a method, a device and equipment for controlling double-stage SCR urea injection quantity.
Background
At present, a DOC (diesel oxidation catalyst) +DPF (diesel particulate filter) +SCR (selective catalytic reduction) +ASC (ammonia purification catalyst) scheme is generally adopted in the Guohu aftertreatment system to treat emission pollutants in automobile exhaust, and along with the upgrading of emission regulations in the next stage, the emission limit requirements on pollutants such as nitrogen oxides are further improved, the aftertreatment system needs to adopt a two-stage SCR scheme, namely 'ccSCR (compact coupling selective catalytic reduction) +DOC+DPF+SCR+ASC', the two-stage SCR aftertreatment system needs that front-stage SCR and rear-stage SCR can independently control urea injection, and front-stage SCR and rear-stage SCR coordinated control is needed.
At present, for the control of a two-stage SCR system, a mode is commonly adopted that the temperatures of a first-stage SCR inlet and a second-stage SCR inlet are respectively obtained in real time, the SCR cooperative control state is determined according to the two temperatures, and the urea injection quantity of the first-stage SCR and the urea injection quantity of the second-stage SCR are determined according to the SCR cooperative control state. However, the control mode only determines the SCR cooperative control state according to the inlet temperatures of the primary SCR and the secondary SCR, the requirements of different engine working conditions are not considered, and the relation between the two-stage SCR control and the DPF is not considered.
Disclosure of Invention
The application provides a control method, a device and equipment for the urea injection quantity of a double-stage SCR, which are used for determining the coordination control state of the double-stage SCR according to the working mode of an engine, reducing the emission of nitrogen oxides more effectively aiming at different working modes, and simultaneously considering the influence of the DPF state on the coordination control of the double-stage SCR to realize the efficient coordination control of the urea injection quantity of the double-stage SCR.
In a first aspect, an embodiment of the present application provides a dual-stage SCR urea injection control method, where the dual-stage SCR urea injection control method includes:
Acquiring a real-time working mode of an engine, and determining control modes of a front-stage SCR and a rear-stage SCR according to the acquired working mode;
Based on the determined control mode, the front-stage SCR and the rear-stage SCR perform corresponding urea injection amount calculation, and control mode switching is performed according to the working state of the SCR;
the control modes of the front-stage SCR comprise an initial mode, a target efficiency mode and a high efficiency mode, and the control modes of the rear-stage SCR comprise the initial mode and the high efficiency mode.
With reference to the first aspect, in one embodiment,
The working modes of the engine comprise a normal mode and a special mode;
the conventional mode is a working condition mode of the engine which works for a long time frequently, and comprises a default mode, an economic mode and a dynamic mode;
the special mode is a special working condition mode which is entered by the engine for realizing a special effect, and comprises a regeneration mode and a temperature discharge management mode;
The regeneration mode comprises a DPF regeneration mode, a pre-stage SCR desulfurization regeneration mode, a post-stage SCR desulfurization regeneration mode and a decrystallization regeneration mode;
the temperature exhaust management mode comprises a pre-stage SCR heating mode, a DOC heating mode and a post-stage SCR heating mode.
With reference to the first aspect, in one implementation manner, the control modes of the front-stage SCR and the rear-stage SCR are determined according to the acquired operation mode, and specifically:
when the working mode of the engine is a normal mode, determining that the initial control mode of the front-stage SCR is a target efficiency mode, and the initial control mode of the rear-stage SCR is a high efficiency mode;
when the working mode of the engine is a special mode, the control modes of the corresponding front-stage SCR and the corresponding rear-stage SCR are selected based on the working condition characteristics of the special mode.
With reference to the first aspect, in one embodiment,
The control mode switching is performed according to the working state of the SCR, specifically, when the working mode of the engine is a normal mode, the control mode switching is performed according to the working state change of the SCR;
The control mode switching is performed according to the working state change of the SCR, wherein the control mode switching of the preceding SCR specifically includes:
when the current SCR is in the target efficiency mode, if the current SCR efficiency target is larger than the first limit value, the current SCR is switched to the high efficiency mode;
When the front-stage SCR is in the high-efficiency mode, if the current front-stage SCR efficiency target is smaller than the second limit value and the nitrogen oxide conversion rate of the rear-stage SCR is larger than the third limit value, the front-stage SCR is switched to the target efficiency mode.
With reference to the first aspect, in one embodiment,
The control mode switching is performed according to the working state of the SCR, specifically, when the working mode of the engine is a normal mode, the control mode switching is performed according to the working state change of the SCR;
The control mode switching is performed according to the working state change of the SCR, wherein the control mode switching of the subsequent SCR specifically includes:
When the control mode of the rear-stage SCR is the high-efficiency mode, if the temperature of the rear-stage SCR is smaller than the minimum urea injection temperature, the rear-stage SCR is switched to the initial mode, and when the temperature of the rear-stage SCR is not smaller than the minimum urea injection temperature, the rear-stage SCR is switched to the high-efficiency mode.
With reference to the first aspect, in one embodiment,
The initial mode of the pre-stage SCR is that urea injection is stopped;
The target efficiency mode of the front-stage SCR is that urea injection quantity is calculated based on the target efficiency of the front-stage SCR;
the high efficiency mode of the pre-stage SCR is that urea injection quantity is calculated based on a pre-stage SCR ammonia storage target;
the initial mode of the rear-stage SCR is that urea injection is stopped;
the high-efficiency mode of the rear-stage SCR is that urea injection quantity is calculated based on an ammonia storage target of the rear-stage SCR.
With reference to the first aspect, in an implementation manner, the calculating the urea injection amount based on the previous stage SCR efficiency target specifically includes:
determining a primary SCR basic efficiency target according to the inlet temperature and the exhaust flow of the primary SCR and the current working mode of the engine;
Determining a first correction coefficient of a front-stage SCR efficiency target according to the DPF carbon loading and the DPF temperature;
Determining a second correction coefficient of the efficiency target of the front-stage SCR according to the nitrogen oxide conversion rate of the rear-stage SCR;
Determining a pre-stage SCR efficiency target based on the pre-stage SCR basic efficiency target, the first correction coefficient of the pre-stage SCR efficiency target and the second correction coefficient of the pre-stage SCR efficiency target;
determining the urea quantity required for converting nitrogen oxides according to the concentration of nitrogen oxides at the inlet of the pre-stage SCR, the exhaust flow rate of the pre-stage SCR and the temperature of the pre-stage SCR;
Based on the determined urea quantity required for converting the nitrogen oxides and the determined pre-stage SCR efficiency target, obtaining a theoretical urea injection quantity of the pre-stage SCR;
Calculating the actual conversion efficiency of the pre-stage SCR according to the concentration of nitrogen oxides at the inlet of the pre-stage SCR and the concentration of nitrogen oxides at the outlet of the pre-stage SCR;
obtaining a correction coefficient of urea injection quantity of the pre-stage SCR according to the calculated actual conversion efficiency of the pre-stage SCR and the target conversion efficiency of the pre-stage SCR;
And obtaining the final urea injection quantity of the pre-stage SCR according to the obtained urea injection quantity correction coefficient of the pre-stage SCR and the theoretical urea injection quantity of the pre-stage SCR.
With reference to the first aspect, in an implementation manner, the calculating the urea injection amount based on the pre-stage SCR ammonia storage target specifically includes:
searching a preset MAP table according to the temperature of the previous-stage SCR to determine the target ammonia storage amount of the previous-stage SCR;
According to the deviation between the target ammonia storage amount of the former-stage SCR and the actual ammonia storage amount of the former-stage SCR, ammonia required by ammonia storage control is obtained through PID control;
Obtaining ammonia demand based on ammonia required for ammonia storage control and ammonia required for conversion of nitrogen oxides by the pre-stage SCR;
And converting the ammonia demand into urea demand to obtain the urea injection quantity of the pre-stage SCR.
In a second aspect, an embodiment of the present application provides a dual-stage SCR urea injection amount control device, including:
The determining module is used for acquiring a real-time working mode of the engine and determining control modes of the front-stage SCR and the rear-stage SCR according to the acquired working mode;
the execution module is used for calculating the corresponding urea injection quantity of the front-stage SCR and the rear-stage SCR based on the determined control mode and switching the control mode according to the working state of the SCR;
the control modes of the front-stage SCR comprise an initial mode, a target efficiency mode and a high efficiency mode, and the control modes of the rear-stage SCR comprise the initial mode and the high efficiency mode.
In a third aspect, an embodiment of the present application provides a dual-stage SCR urea injection amount control apparatus, where the dual-stage SCR urea injection amount control apparatus includes a processor, a memory, and a dual-stage SCR urea injection amount control program stored on the memory and executable by the processor, where the dual-stage SCR urea injection amount control program, when executed by the processor, implements the steps of the dual-stage SCR urea injection amount control method described above.
The technical scheme provided by the embodiment of the application has the beneficial effects that:
The control modes of the front-stage SCR and the rear-stage SCR are determined according to the obtained working modes, the corresponding urea injection quantity is calculated based on the determined control modes, the control modes are switched according to the working states of the SCRs, the coordinated control states of the two-stage SCRs are determined according to the working modes of the engine, the emission of nitrogen oxides is effectively reduced according to different working modes, meanwhile, the influence of the DPF state on the coordinated control of the two-stage SCRs is considered, and the efficient coordinated control of the urea injection quantity of the two-stage SCRs is realized.
Drawings
FIG. 1 is a schematic flow chart of a dual-stage SCR urea injection control method of the present application;
FIG. 2 is a schematic diagram of a dual stage SCR;
FIG. 3 is a functional block diagram of a dual-stage SCR urea injection control device according to the present application;
FIG. 4 is a schematic diagram of the hardware architecture of the dual-stage SCR urea injection control device of the present application.
Detailed Description
In order that those skilled in the art will better understand the present application, a technical solution in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in which it is apparent that the described embodiments are only some embodiments of the present application, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.
For the purpose of making the objects, technical solutions and advantages of the present application more apparent, the embodiments of the present application will be described in further detail with reference to the accompanying drawings.
In a first aspect, an embodiment of the present application provides a method for controlling a urea injection amount of a two-stage SCR, where two-stage SCR control is coordinated according to requirements of different engine operating conditions, and urea injection amounts of a front-stage SCR and a rear-stage SCR are coordinated according to influences between the SCR and a DPF, so as to implement efficient coordination control of the urea injection amounts of the two-stage SCR.
In an embodiment, referring to fig. 1, fig. 1 is a flow chart of a dual-stage SCR urea injection control method according to the present application. As shown in FIG. 1, the two-stage SCR urea injection quantity control method comprises the following steps:
s1, acquiring a real-time working mode of an engine, and determining control modes of a front-stage SCR and a rear-stage SCR according to the acquired working mode;
S2, based on the determined control mode, the front-stage SCR and the rear-stage SCR perform corresponding urea injection amount calculation, and control mode switching is performed according to the working state of the SCR;
the control modes of the front-stage SCR comprise an initial mode, a target efficiency mode and a high efficiency mode, and the control modes of the rear-stage SCR comprise the initial mode and the high efficiency mode.
Referring to FIG. 2, a two-stage SCR structure is shown, a front-stage SCR (i.e. ccSCR/ccASC) is installed at the rear end of a turbine outlet, a nitrogen oxide sensor, a temperature sensor and a urea nozzle are also installed between ccSCR and the turbine outlet, the nitrogen oxide sensor and the temperature sensor respectively measure the concentration and the temperature of nitrogen oxide before ccSCR, the urea nozzle is used for executing the urea injection amount required by injection ccSCR, a DOC, a DPF and a rear-stage SCR are installed behind the front-stage SCR, and the temperature sensor and the urea nozzle are installed in front of the rear-stage SCR for measuring the inlet temperature of the rear-stage SCR and injecting urea to the rear-stage SCR.
The operation mode of the engine is determined according to the engine operation state and/or the engine operation condition. The working modes of the engine comprise a conventional mode and a special mode, wherein the conventional mode is a working condition mode of the engine which is frequently operated for a long time and comprises a default mode, an economic mode and a dynamic mode, the special mode is a special working condition mode which is entered by the engine for realizing a specific effect and comprises a regeneration mode and a temperature discharge management mode, the regeneration mode comprises a DPF regeneration mode, a front-stage SCR desulfurization regeneration mode, a rear-stage SCR desulfurization regeneration mode and a crystallization removal regeneration mode, and the temperature discharge management mode comprises a front-stage SCR heating mode, a DOC heating mode and a rear-stage SCR heating mode.
In the application, the control modes of the front-stage SCR and the rear-stage SCR are determined according to the acquired working modes, and the control modes are specifically:
when the working mode of the engine is a normal mode, determining that the initial control mode of the front-stage SCR is a target efficiency mode, and the initial control mode of the rear-stage SCR is a high efficiency mode;
when the working mode of the engine is a special mode, the control modes of the corresponding front-stage SCR and the corresponding rear-stage SCR are selected based on the working condition characteristics of the special mode.
The control modes of the corresponding front-stage SCR and the corresponding rear-stage SCR are selected based on the working condition characteristics of the special mode, and an engineering person selects a proper control mode of the front-stage SCR and the rear-stage SCR according to the working condition characteristics of the specific special mode.
The control modes of the front-stage SCR and the rear-stage SCR are determined according to the acquired working modes, and the control modes further comprise the step that before the temperatures of the front-stage SCR and the rear-stage SCR reach the urea injection temperature, the front-stage SCR and the rear-stage SCR are default to the initial modes, and urea injection is stopped.
In the application, the control mode is switched according to the working state of the SCR, specifically, when the working mode of the engine is a normal mode, the control mode is switched according to the working state change of the SCR;
The control mode switching is performed according to the working state change of the SCR, wherein the control mode switching of the preceding SCR specifically includes:
when the current SCR is in the target efficiency mode, if the current SCR efficiency target is larger than the first limit value, the current SCR is switched to the high efficiency mode;
When the front-stage SCR is in the high-efficiency mode, if the current front-stage SCR efficiency target is smaller than the second limit value and the nitrogen oxide conversion rate of the rear-stage SCR is larger than the third limit value, the front-stage SCR is switched to the target efficiency mode. The first limit is greater than the second limit.
In the application, control mode switching is performed according to the working state change of SCR, wherein the control mode switching of the post-stage SCR specifically comprises the following steps:
When the control mode of the rear-stage SCR is the high-efficiency mode, if the temperature of the rear-stage SCR is smaller than the minimum urea injection temperature, the rear-stage SCR is switched to the initial mode, and when the temperature of the rear-stage SCR is not smaller than the minimum urea injection temperature, the rear-stage SCR is switched to the high-efficiency mode. The minimum urea injection temperature is a calibrated value that represents the minimum temperature at which urea can hydrolyze and react to convert nitrogen oxides in the SCR, and is experimentally obtained by an engineering technician based on SCR catalyst carrier characteristics.
In the application, for the control modes of the front SCR and the rear SCR, the initial mode of the front SCR stops the urea injection, the target efficiency mode of the front SCR calculates the urea injection amount based on the front SCR efficiency target, the high efficiency mode of the front SCR calculates the urea injection amount based on the front SCR ammonia storage target, the initial mode of the rear SCR stops the urea injection, and the high efficiency mode of the rear SCR calculates the urea injection amount based on the rear SCR ammonia storage target.
Further, in an embodiment, calculating the urea injection amount based on the pre-SCR efficiency target specifically includes:
s201, determining a primary SCR basic efficiency target according to the inlet temperature and the exhaust flow of the primary SCR and the current working mode of the engine;
Specifically, according to different working modes of an engine, different SCR basic efficiency target MAP graphs are selected (when the working mode of the engine is a conventional mode, an SCR basic efficiency target MAP graph #01 is selected, when the working mode of the engine is a different special mode, an SCR basic efficiency target MAP graph #02 and #03 is selected, the number of the SCR basic efficiency target MAP graphs and the corresponding relation with the working modes of the engine are determined by engineering technicians according to the number of the working modes of the engine and the working condition difference degree of each working mode, the number of the SCR basic efficiency target MAP graphs does not exceed the number of the working modes of the engine), then a front-stage SCR basic efficiency target is obtained from the selected SCR basic efficiency target MAP graphs according to the inlet temperature of the front-stage SCR and the exhaust flow of the front-stage SCR, the SCR basic efficiency target MAP is in MAP calibration, and the relation between the inlet temperature of the front-stage SCR and the SCR basic efficiency target is calibrated by the technicians in the specific working mode of the engine;
s202, determining a first correction coefficient of a front-stage SCR efficiency target according to DPF carbon loading and DPF temperature;
Specifically, according to DPF carbon loading and DPF temperature, searching MAP to obtain a first correction coefficient of a pre-stage SCR efficiency target, wherein the coefficient range is 0-2, and the MAP is calibrated by engineering personnel;
s203, determining a second correction coefficient of the efficiency target of the front-stage SCR according to the nitrogen oxide conversion rate of the rear-stage SCR;
specifically, according to the nitrogen oxide conversion rate of the rear-stage SCR, checking MAP to obtain a second correction coefficient of the front-stage SCR efficiency target, wherein the coefficient range is 0-2, and the MAP is calibrated by engineering personnel;
s204, determining a pre-stage SCR efficiency target based on the pre-stage SCR basic efficiency target, the first correction coefficient of the pre-stage SCR efficiency target and the second correction coefficient of the pre-stage SCR efficiency target;
Specifically, multiplying a pre-stage SCR basic efficiency target by a first correction coefficient of the pre-stage SCR efficiency target, and multiplying the first correction coefficient of the pre-stage SCR efficiency target to obtain the pre-stage SCR efficiency target;
It should be noted that different pre-SCR base efficiency targets may be selected for different engine operating modes; determining a first correction coefficient according to the carbon loading of the DPF and the temperature of the DPF, and correcting the target efficiency of the front-stage SCR, so that when the working condition of the passive regeneration of the DPF is suitable, the target efficiency of the front-stage SCR is adjusted to promote the passive regeneration of the DPF, prolong the active regeneration interval of the DPF and reduce the regeneration frequency of the DPF, thereby reducing the oil consumption;
s205, determining the urea quantity required for converting nitrogen oxides according to the concentration of nitrogen oxides at the inlet of the pre-stage SCR, the exhaust flow rate of the pre-stage SCR and the temperature of the pre-stage SCR;
specifically, the concentration of nitrogen oxide at the inlet of the pre-stage SCR is multiplied by the exhaust flow of the pre-stage SCR, and then multiplied by the reaction metering ratio of the nitrogen oxide and the ammonia to obtain ammonia required for converting the nitrogen oxide, and the ammonia is multiplied by 5.425 to obtain the urea amount required for converting the nitrogen oxide;
s206, obtaining a theoretical urea injection amount of the front-stage SCR based on the determined urea amount required for converting the nitrogen oxides and the determined front-stage SCR efficiency target;
specifically, the urea quantity required for converting nitrogen oxides is multiplied by a pre-stage SCR efficiency target to obtain the theoretical urea injection quantity of the pre-stage SCR;
S207, calculating the actual conversion efficiency of the pre-stage SCR according to the concentration of nitrogen oxides at the inlet of the pre-stage SCR and the concentration of nitrogen oxides at the outlet of the pre-stage SCR;
Specifically, the actual conversion efficiency of the preceding scr= (nitrogen oxide concentration at the inlet of the preceding SCR-nitrogen oxide concentration at the outlet of the preceding SCR)/nitrogen oxide concentration at the inlet of the preceding SCR;
S208, obtaining a correction coefficient of urea injection quantity of the pre-stage SCR according to the calculated actual conversion efficiency of the pre-stage SCR and the target conversion efficiency of the pre-stage SCR;
specifically, according to the deviation between the actual conversion efficiency of the former-stage SCR and the target conversion efficiency of the former-stage SCR, searching MAP to obtain a urea injection quantity correction coefficient of the former-stage SCR;
S209, obtaining the final urea injection quantity of the pre-stage SCR according to the obtained urea injection quantity correction coefficient of the pre-stage SCR and the theoretical urea injection quantity of the pre-stage SCR. Specifically, the urea injection amount correction coefficient of the pre-stage SCR is multiplied by the theoretical urea injection amount of the pre-stage SCR to obtain the final urea injection amount of the pre-stage SCR.
Further, in an embodiment, calculating the urea injection amount based on the pre-SCR ammonia storage target specifically includes:
S211, checking a preset MAP table according to the temperature of the previous SCR to determine the target ammonia storage amount of the previous SCR, wherein the actual ammonia storage amount of the previous SCR is the actual ammonia storage amount of the previous SCR plus the ammonia newly entering the SCR and subtracting the ammonia consumed by converting nitrogen oxides;
s212, obtaining ammonia required by ammonia storage control through PID control according to the deviation between the target ammonia storage amount of the previous SCR and the actual ammonia storage amount of the previous SCR;
S213, obtaining ammonia demand based on ammonia required by ammonia storage control and ammonia required by conversion of nitrogen oxides by the pre-stage SCR;
Specifically, adding ammonia required by ammonia storage control to ammonia required by conversion of nitrogen oxides by the front-stage SCR to obtain ammonia demand, wherein the ammonia required by conversion of nitrogen oxides by the front-stage SCR is the concentration of nitrogen oxides at an inlet of the front-stage SCR multiplied by the exhaust flow rate of the front-stage SCR, and then multiplied by the reaction metering ratio of the nitrogen oxides to the ammonia;
And S214, converting the ammonia demand into urea demand to obtain the urea injection quantity of the front-stage SCR. Specifically, the ammonia demand is multiplied by 5.425 to obtain the urea demand, thereby obtaining the urea injection quantity of the pre-stage SCR.
In the high-efficiency mode for the latter SCR, the urea injection amount is calculated based on the ammonia storage target of the latter SCR in a similar manner to that for the former SCR.
According to the two-stage SCR urea injection quantity control method, the real-time working mode of the engine is obtained, the control modes of the front-stage SCR and the rear-stage SCR are determined according to the obtained working mode, then the corresponding urea injection quantity calculation is carried out by the front-stage SCR and the rear-stage SCR based on the determined control modes, the control mode is switched according to the working state of the SCR, the coordinated control state of the two-stage SCR is determined according to the working mode of the engine, the emission of nitrogen oxides is effectively reduced for different working modes, meanwhile, the influence of the DPF state on the coordinated control of the two-stage SCR is considered, and the efficient coordinated control of the urea injection quantity of the two-stage SCR is realized.
In a second aspect, the embodiment of the application further provides a two-stage SCR urea injection quantity control device.
In an embodiment, referring to fig. 3, fig. 3 is a schematic diagram of a functional module of a dual-stage SCR urea injection control device according to the present application. As shown in FIG. 3, the two-stage SCR urea injection quantity control device comprises a determining module and an executing module.
The system comprises a determining module, an executing module and a control module, wherein the determining module is used for acquiring a real-time working mode of an engine and determining control modes of a front-stage SCR and a rear-stage SCR according to the acquired working mode, the executing module is used for calculating corresponding urea injection amounts based on the determined control modes, and switching the control modes according to the working state of the SCR, wherein the control modes of the front-stage SCR comprise an initial mode, a target efficiency mode and a high efficiency mode, and the control modes of the rear-stage SCR comprise the initial mode and the high efficiency mode.
The function implementation of each module in the two-stage SCR urea injection control device corresponds to each step in the two-stage SCR urea injection control method embodiment, and the function and implementation process of each module are not described in detail herein.
In a third aspect, an embodiment of the present application provides a dual-stage SCR urea injection amount control apparatus, where the dual-stage SCR urea injection amount control apparatus may be a device with a data processing function, such as a personal computer (personal computer, PC), a notebook computer, a server, or the like.
Referring to fig. 4, fig. 4 is a schematic hardware structure diagram of a dual-stage SCR urea injection control device according to an embodiment of the present application. In an embodiment of the application, the two-stage SCR urea injection quantity control device can comprise a processor, a memory, a communication interface and a communication bus.
The communication bus may be of any type for implementing the processor, memory, and communication interface interconnections.
The communication interfaces include input/output (I/O) interfaces, physical interfaces, logical interfaces, and the like, for interconnecting devices within the dual-stage SCR urea injection amount control device, and for interconnecting the dual-stage SCR urea injection amount control device with other devices (e.g., other computing devices or user devices). The physical interface may be an ethernet interface, an optical fiber interface, an ATM interface, etc., and the user device may be a Display screen (Display), a Keyboard (Keyboard), etc.
The memory may be various types of storage media such as random access memory (randomaccess memory, RAM), read-only memory (ROM), nonvolatile RAM (non-volatileRAM, NVRAM), flash memory, optical memory, hard disk, programmable ROM (PROM), erasable PROM (erasable PROM, EPROM), electrically erasable PROM (ELECTRICALLY ERASABLE PROM, EEPROM), and the like.
The processor may be a general-purpose processor, and the general-purpose processor may call a two-stage SCR urea injection amount control program stored in the memory, and execute the two-stage SCR urea injection amount control method provided by the embodiment of the present application. For example, the general purpose processor may be a central processing unit (central processing unit, CPU). The method executed when the two-stage SCR urea injection control program is called may refer to various embodiments of the two-stage SCR urea injection control method of the present application, and will not be described herein.
Those skilled in the art will appreciate that the hardware configuration shown in fig. 4 is not limiting of the application and may include more or fewer components than shown, or may combine certain components, or a different arrangement of components.
The terms "comprising" and "having" and any variations thereof in the description and claims of the application and in the foregoing drawings are intended to cover non-exclusive inclusions. For example, a process, method, system, article, or apparatus that comprises a list of steps or elements is not limited to only those listed steps or elements but may include other steps or elements not listed or inherent to such process, method, article, or apparatus. The terms "first," "second," and "third," etc. are used for distinguishing between different objects and not necessarily for describing a sequential or chronological order, and are not limited to the fact that "first," "second," and "third" are not identical.
In describing embodiments of the present application, "exemplary," "such as," or "for example," etc., are used to indicate by way of example, illustration, or description. Any embodiment or design described herein as "exemplary," "such as" or "for example" is not necessarily to be construed as preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary," "such as" or "for example," etc., is intended to present related concepts in a concrete fashion.
In the description of the embodiment of the present application, "/" means or, for example, a/B may mean a or B, and "and/or" in the text is merely an association relationship describing an association object, means that three relationships may exist, for example, a and/or B, three cases where a exists alone, a and B exist together, and B exists alone, and further, in the description of the embodiment of the present application, "a plurality" means two or more.
In some of the processes described in the embodiments of the present application, a plurality of operations or steps occurring in a particular order are included, but it should be understood that the operations or steps may be performed out of the order in which they occur in the embodiments of the present application or in parallel, the sequence numbers of the operations merely serve to distinguish between the various operations, and the sequence numbers themselves do not represent any order of execution. In addition, the processes may include more or fewer operations, and the operations or steps may be performed in sequence or in parallel, and the operations or steps may be combined.
From the above description of the embodiments, it will be clear to those skilled in the art that the above-described embodiment method may be implemented by means of software plus a necessary general hardware platform, but of course may also be implemented by means of hardware, but in many cases the former is a preferred embodiment. Based on such understanding, the technical solution of the present application may be embodied essentially or in a part contributing to the prior art in the form of a software product stored in a storage medium (e.g. ROM/RAM, magnetic disk, optical disk) as described above, comprising several instructions for causing a terminal device to perform the method according to the embodiments of the present application.
The foregoing description is only of the preferred embodiments of the present application, and is not intended to limit the scope of the application, but rather is intended to cover any equivalents of the structures or equivalent processes disclosed herein or in the alternative, which may be employed directly or indirectly in other related arts.
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| CN118442155A (en) * | 2024-05-16 | 2024-08-06 | 中汽研汽车检验中心（天津）有限公司 | A diesel engine dual-stage SCR after-treatment control method and system |
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| DE102018213382A1 (en) * | 2018-08-09 | 2020-02-13 | Robert Bosch Gmbh | Method for operating a conveyor module of an SCR catalyst system |
| GB2589150B (en) * | 2019-11-25 | 2022-02-23 | Delphi Automotive Systems Lux | Dual SCR system control method |
| CN118686686B (en) * | 2024-08-29 | 2024-12-17 | 潍柴动力股份有限公司 | Urea injection control method and device |
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| CN118442155A (en) * | 2024-05-16 | 2024-08-06 | 中汽研汽车检验中心（天津）有限公司 | A diesel engine dual-stage SCR after-treatment control method and system |
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