CN111396179A - Method and device for determining urea crystal amount in engine - Google Patents
Method and device for determining urea crystal amount in engine Download PDFInfo
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- CN111396179A CN111396179A CN202010246445.3A CN202010246445A CN111396179A CN 111396179 A CN111396179 A CN 111396179A CN 202010246445 A CN202010246445 A CN 202010246445A CN 111396179 A CN111396179 A CN 111396179A
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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
- F01N11/00—Monitoring or diagnostic devices for exhaust-gas treatment apparatus, e.g. for catalytic activity
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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]
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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
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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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- 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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- 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)
- 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
A method and apparatus for determining an amount of urea crystals in an engine is disclosed. Wherein, the method comprises the following steps: calibrating the exhaust temperature and urea injection quantity of the exhaust gas of the engine according to different exhaust gas exhaust flow rates of the engine to obtain multiple groups of calibration values, wherein each group of calibration values comprises the exhaust temperature and the urea injection quantity of the exhaust gas; drawing a control curve graph of exhaust gas temperature and urea injection quantity according to a plurality of groups of calibration values, wherein the abscissa of the control curve graph is the value of the exhaust gas temperature, and the ordinate of the control curve graph is the value of the urea injection quantity; dividing the control curve graph into a plurality of working condition areas; and calculating the urea crystallization amount of the engine working in each working condition region according to the urea crystallization amount calculation method corresponding to each working condition region in the plurality of working condition regions. The method solves the technical problems that the traditional urea crystallization calculation method needs large workload, consumes more calculation resources, is low in calculation rate and is not accurate enough in calculation result.
Description
Technical Field
The present application relates to the field of engines, and more particularly, to a method and apparatus for determining the amount of urea crystals in an engine.
Background
When exhaust gas from a diesel engine is treated, the application of Selective Catalytic Reduction (SCR) as a main technology for meeting higher emission regulations of the diesel engine is gradually expanding. The urea solution sprays the in-process in the blast pipe, receives the influence of high temperature waste gas, can produce evaporation and pyrolysis phenomenon, and the liquid drop inevitably can collide the blast pipe wall on, causes the temperature in this region to reduce by a wide margin, and then forms crystallization deposition phenomenon on the wall, can cause the blast pipe to block up when crystallization is serious, increases exhaust back pressure, increases the oil consumption, seriously influences aspects such as car economy, dynamic nature and emission level. Therefore, it is necessary to consider the problem of urea crystallization and take appropriate measures to avoid the formation of urea crystals as much as possible.
The existing method for calculating the crystallization amount of urea after engine post-treatment comprises the following steps: calibrating a plurality of urea crystallization rate MAP graphs under different exhaust temperature, exhaust flow and urea injection quantity working conditions, calculating to obtain urea crystallization rate by calibrating urea crystallization rate factors, calculating urea crystallization quantity in a plurality of sampling periods, and further performing selective optimization calculation on accumulated urea crystallization quantity.
The existing urea crystallization calculation method needs to calibrate a plurality of MAP graphs and a plurality of parameters, needs to calculate urea crystallization factors to obtain urea crystallization rate, determines urea crystallization amount in a sampling period according to the actual urea crystallization rate under a specific working condition, carries out selection optimization, calibrates a corrected curve graph of the urea crystallization amount and the crystallization rate, and calculates integral accumulation according to a correction coefficient to obtain the urea crystallization amount in a plurality of sampling periods. Therefore, the calculation method is difficult to calibrate, requires large workload, consumes more calculation resources, has low calculation rate and takes the factors into consideration insufficiently and comprehensively. In the case of urea deposition, crystal formation and removal, the calculation result of the amount of urea crystals is not accurate enough.
Aiming at the problems of large workload, high consumption of computing resources, low computing rate and inaccurate computing result of the existing urea crystallization computing method, an effective solution is not provided at present.
Disclosure of Invention
The embodiment of the application provides a method and a device for determining urea crystallization amount in an engine, and aims to at least solve the technical problems that the existing urea crystallization calculation method is large in required workload, high in consumed calculation resource, low in calculation rate and inaccurate in calculation result.
According to an aspect of an embodiment of the present application, there is provided a method of determining an amount of urea crystals in an engine, comprising: calibrating the exhaust temperature and urea injection quantity of the exhaust gas of the engine according to different exhaust gas exhaust flow rates of the engine to obtain multiple groups of calibration values, wherein each group of calibration values comprises the exhaust temperature and the urea injection quantity of the exhaust gas; drawing a control curve graph of exhaust gas temperature and urea injection quantity according to a plurality of groups of calibration values, wherein the abscissa of the control curve graph is the value of the exhaust gas temperature, and the ordinate of the control curve graph is the value of the urea injection quantity; dividing the control curve graph into a plurality of working condition areas; and calculating the urea crystallization amount of the engine working in each working condition region according to the urea crystallization amount calculation method corresponding to each working condition region in the plurality of working condition regions.
Optionally, calibrating the exhaust gas temperature and the urea injection amount of the engine according to different exhaust gas exhaust flow rates of the engine, including: when the exhaust gas flow is lower than a first preset threshold value, calibrating the exhaust gas temperature of the engine and the urea injection quantity when the temperature in the exhaust pipe of the engine reaches a first preset temperature and a second preset temperature respectively to obtain two groups of calibration values serving as a first group of calibration values; when the exhaust gas flow rate is higher than a second preset threshold value, calibrating the exhaust gas temperature and the urea injection amount of the engine at a first preset temperature and a second preset temperature respectively to obtain two groups of calibration values serving as a second group of calibration values.
Optionally, drawing a control curve graph of exhaust gas temperature and urea injection amount according to multiple sets of calibration values, including: performing linear interpolation calculation according to the first group of calibration values to obtain a plurality of control values, and drawing a first control curve according to the plurality of control values calculated according to the first group of calibration values; and performing linear interpolation calculation according to the second group of calibration values to obtain a plurality of control values, drawing a second control curve according to the plurality of control values calculated according to the second group of calibration values, and forming a control curve graph by the first control curve and the second control curve together.
Optionally, dividing the control curve into a plurality of operating condition regions includes: the control curve diagram is divided into three operating condition regions according to the residual amounts of moisture and urea in a mixer of the engine, wherein the first operating condition region is an amorphous region, the second operating condition region is a liquid region, and the third operating condition region is a crystallization region.
Optionally, calculating the urea crystallization amount when the engine operates in each operating condition region according to the urea crystallization amount calculation method corresponding to each operating condition region in the plurality of operating condition regions respectively, includes: judging whether the engine works in an amorphous area or not; if the engine is judged to work in the non-crystallization area, detecting whether residual urea exists in an exhaust pipe of the engine; if residual urea exists in an exhaust pipe of the engine and no moisture exists, calculating a first urea crystallization amount corresponding to the residual urea according to a first formula; if residual urea does not exist in the exhaust pipe of the engine and moisture exists in the exhaust pipe of the engine, the first moisture residual quantity is calculated according to a second formula.
Optionally, if it is determined that the engine is not operating in the amorphous region, the method further comprises: judging whether the engine works in a liquid area or not; if the engine does not work in the liquid area, determining that the engine works in the crystallization area, and calculating according to a third formula to obtain a second urea crystallization amount; and if the engine is judged to work in the liquid state area, calculating according to a fourth formula to obtain a second moisture residual quantity.
Optionally, after obtaining the first urea crystal amount, the second urea crystal amount, the first residual moisture amount, and the second residual moisture amount, the method comprises: taking the sum of the first urea crystal amount and the second urea crystal amount as the total urea crystal amount in an exhaust pipe of the engine; the sum of the first moisture residual amount and the second moisture residual amount is taken as a total moisture residual amount in an exhaust pipe of the engine.
Optionally, before calibrating the exhaust gas temperature and the urea injection amount of the engine, the method further comprises: the amount of urea crystals and the residual amount of moisture in the exhaust pipe of the engine are initialized to zero.
According to another aspect of the embodiments of the present application, there is also provided an apparatus for determining an amount of urea crystals in an engine, including: the calibration module is used for calibrating the exhaust temperature and urea injection quantity of the exhaust of the engine according to different exhaust flow rates of the exhaust of the engine to obtain a plurality of groups of calibration values, and each group of calibration values comprises the exhaust temperature and the urea injection quantity; the drawing module is used for drawing a control curve graph of the exhaust temperature and the urea injection amount of the tail gas according to a plurality of groups of calibration values, wherein the abscissa of the control curve graph is the value of the exhaust temperature of the tail gas, and the ordinate of the control curve graph is the value of the urea injection amount; the dividing module is used for dividing the control curve graph into a plurality of working condition areas; and the calculation module is used for calculating the urea crystallization amount of the engine working in each working condition region according to the urea crystallization amount calculation method corresponding to each working condition region in the plurality of working condition regions.
According to still another aspect of the embodiments of the present application, there is also provided a storage medium including a stored program, wherein the apparatus in which the storage medium is controlled when the program is executed performs the above method of determining the amount of urea crystals in an engine.
According to another aspect of the embodiments of the present application, there is also provided a processor for running a program stored in a memory, wherein the program when running performs the above method of determining an amount of urea crystals in an engine.
In the embodiment of the application, the exhaust temperature and urea injection amount of the exhaust gas of the engine are calibrated according to different exhaust flow rates of the exhaust gas of the engine to obtain a plurality of groups of calibrated values, wherein each group of calibrated values comprises the exhaust temperature and the urea injection amount of the exhaust gas; drawing a control curve graph of exhaust gas temperature and urea injection quantity according to a plurality of groups of calibration values, wherein the abscissa of the control curve graph is the value of the exhaust gas temperature, and the ordinate of the control curve graph is the value of the urea injection quantity; dividing the control curve graph into a plurality of working condition areas; the method comprises the steps of calculating the urea crystallization amount of an engine working in each working condition area according to the urea crystallization amount calculation method corresponding to each working condition area in a plurality of working condition areas, analyzing exhaust flow, exhaust temperature and urea injection amount of post-treatment of the engine, and selecting corresponding urea crystallization calculation methods and indexes according to different working condition points of the engine to calculate the urea crystallization amount, so that the efficiency of the urea crystallization amount calculation method is improved, the accuracy of the urea crystallization amount calculation method is improved, the technical effect of reliable data support is provided for removing urea crystallization, and the technical problems that the traditional urea crystallization calculation method is large in required workload, large in consumed calculation resources, slow in calculation rate and inaccurate in calculation result are solved.
Drawings
The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the application and together with the description serve to explain the application and not to limit the application. In the drawings:
FIG. 1 is a flow chart of a method of determining an amount of urea crystals in an engine according to an embodiment of the present application;
FIG. 2 is a graph of exhaust temperature versus urea injection amount control according to an embodiment of the present application;
FIG. 3 is a flow chart of another method of determining an amount of urea crystals in an engine according to the present application;
FIG. 4 is a block diagram of an apparatus for determining an amount of urea crystals in an engine according to an embodiment of the present application.
Detailed Description
In order to make the technical solutions better understood by those skilled in the art, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only partial embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
It should be noted that the terms "first," "second," and the like in the description and claims of this application and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the application described herein are capable of operation in sequences other than those illustrated or described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
In accordance with an embodiment of the present application, there is provided an embodiment of a method of determining an amount of urea crystals in an engine, it is noted that the steps illustrated in the flowchart of the drawings may be performed in a computer system, such as a set of computer-executable instructions, and that while a logical order is illustrated in the flowchart, in some cases the steps illustrated or described may be performed in an order different than presented herein.
FIG. 1 is a flow chart of a method of determining an amount of urea crystals in an engine, as shown in FIG. 1, according to an embodiment of the present application, the method comprising the steps of:
and S102, calibrating the exhaust gas temperature and the urea injection quantity of the engine according to different exhaust gas exhaust flow rates of the engine to obtain multiple groups of calibration values, wherein each group of calibration values comprises the exhaust gas temperature and the urea injection quantity.
And step S104, drawing a control curve graph of the exhaust gas temperature and the urea injection amount according to a plurality of groups of calibration values, wherein the abscissa of the control curve graph is the value of the exhaust gas temperature, and the ordinate of the control curve graph is the value of the urea injection amount.
And step S106, dividing the control curve graph into a plurality of working condition areas.
And S108, calculating the urea crystallization amount of the engine working in each working condition area according to the urea crystallization amount calculation method corresponding to each working condition area in the plurality of working condition areas.
Through the steps, the exhaust flow, the exhaust temperature and the urea injection amount of the post-treatment of the engine are analyzed, and the urea crystallization amount is calculated by selecting the corresponding urea crystallization calculation method and index according to different working condition points of the engine, so that the efficiency of the urea crystallization amount calculation method is improved, the accuracy of the urea crystallization amount calculation method is improved, and the technical effect of providing reliable data support for removing urea crystallization is achieved.
According to an alternative embodiment of the present application, step S102 may be implemented by: when the exhaust gas flow is lower than a first preset threshold value, calibrating the exhaust gas temperature of the engine and the urea injection quantity when the temperature in the exhaust pipe of the engine reaches a first preset temperature and a second preset temperature respectively to obtain two groups of calibration values serving as a first group of calibration values; when the exhaust gas flow rate is higher than a second preset threshold value, calibrating the exhaust gas temperature and the urea injection amount of the engine at a first preset temperature and a second preset temperature respectively to obtain two groups of calibration values serving as a second group of calibration values.
When water contacts the hot iron wall, a layer of water vapor forms at the bottom of the water droplets, separating the water from the iron wall, so that the water droplets are suspended, and the suspended water droplets temporarily cannot absorb more heat, slowing down the vaporization rate, which is the leden-frowster effect. Calibrating the exhaust temperature and the urea injection quantity at low exhaust flow, and calibrating two groups of control points at a Laden Frost unstable point 295 ℃ (the temperature is also the temperature in the exhaust pipe) and a Laden Frost stable point 320 ℃ respectively; similarly, the two sets of control points are calibrated for exhaust temperature and urea injection amount at high exhaust flow rates.
It should be noted that the first preset threshold and the second preset threshold are not fixed values, and may be set according to needs.
In an alternative embodiment of the present application, step S104 may be implemented by: performing linear interpolation calculation according to the first group of calibration values to obtain a plurality of control values, and drawing a first control curve according to the plurality of control values calculated according to the first group of calibration values; and performing linear interpolation calculation according to the second group of calibration values to obtain a plurality of control values, drawing a second control curve according to the plurality of control values calculated according to the second group of calibration values, and forming the control curve graph by the first control curve and the second control curve together.
Fig. 2 is a control graph of exhaust temperature and urea injection amount according to an embodiment of the present application, in which a plurality of control points are calculated by performing linear interpolation on the calibration value obtained in step S102, and the control graph shown in fig. 2 can be drawn by using the control points obtained by the linear interpolation. The upper curve in fig. 2 is plotted against control points calibrated for exhaust temperature and urea injection amount at high exhaust flow rates, and the lower curve is plotted against control points calibrated for exhaust temperature and urea injection amount at low exhaust flow rates.
According to an alternative embodiment of the present application, step S106 is implemented by: the control curve diagram is divided into three operating condition regions according to the residual amounts of moisture and urea in a mixer of the engine, wherein the first operating condition region is an amorphous region, the second operating condition region is a liquid region, and the third operating condition region is a crystallization region.
Referring to fig. 2, the calibrated control graph is divided into three regions, ① non-crystallization region, ② liquid region, and ③ crystallization region, according to the residual amounts of moisture and urea in the mixer of the engine.
In an alternative embodiment of the present application, the step S108 is executed by: judging whether the engine works in an amorphous area or not; if the engine is judged to work in the non-crystallization area, detecting whether residual urea exists in an exhaust pipe of the engine; if residual urea exists in an exhaust pipe of the engine and no moisture exists, calculating a first urea crystallization amount corresponding to the residual urea according to a first formula; if residual urea does not exist in the exhaust pipe of the engine and moisture exists in the exhaust pipe of the engine, the first moisture residual quantity is calculated according to a second formula.
∑ when residual moisture is present when the operating point of the engine is in region ① (amorphous region)Water (W)If the current moisture evaporation amount is calculated according to the moisture evaporation rate formula, the moisture residual amount is ∑Water (W)Current amount of water evaporated (i.e. second formula above), ∑ if residual urea is present and residual water is not presentUrea＞0，∑Water (W)When the current urea decomposition amount is calculated according to a urea decomposition rate formula, the urea crystallization amount is ∑UreaCurrent urea split (i.e. first formula above) and ∑ if residual moisture and residual urea are not presentUrea＝0，∑Water (W)If 0, no calculation is made.
According to an alternative embodiment of the present application, if it is determined that the engine is not operating in the amorphous region, it is determined whether the engine is operating in the liquid region; if the engine does not work in the liquid area, determining that the engine works in the crystallization area, and calculating according to a third formula to obtain a second urea crystallization amount; and if the engine is judged to work in the liquid state area, calculating according to a fourth formula to obtain a second moisture residual quantity.
When the operating point of the engine is in the region ③ (crystallization region), the water consumption is completed, urea crystals are present, and the percentage of urea crystals is calculated as y% by linear interpolation, so that the current urea crystal amount is y% and the cumulative urea crystal amount is ∑ y% and the urea injection amount is calculated (i.e., the third formula).
When the operating point of the engine is in the ② region (liquid region), the urea is consumed, the moisture residual exists, and the moisture residual percentage x% can be calculated by linear interpolation, so that the current moisture residual amount is x% and the cumulative moisture residual amount is ∑ x% and the urea injection amount (i.e., the fourth formula).
According to an alternative embodiment of the present application, after obtaining the first urea crystal quantity, the second urea crystal quantity, the first moisture residual quantity and the second moisture residual quantity: taking the sum of the first urea crystal amount and the second urea crystal amount as the total urea crystal amount in an exhaust pipe of the engine; the sum of the first moisture residual amount and the second moisture residual amount is taken as a total moisture residual amount in an exhaust pipe of the engine.
By the method, the interval where the working condition point is located is judged, and then the transient urea crystallization rate is calculated by matching with a corresponding calculation formula.
Alternatively, before step S102 is executed, it is necessary to initialize the urea crystal amount and the residual moisture amount in the exhaust pipe of the engine to ∑Water (W)＝0，∑Urea＝0。
FIG. 3 is a flow chart of another method of determining an amount of urea crystals in an engine according to the present application, as shown in FIG. 3, comprising the steps of:
step S301, initializing and electrifying, firstly initializing the engine, and taking ∑Water (W)＝0，∑Urea＝0；
Step S302, calibrating a control point;
step S303, drawing a control curve graph;
step S304, dividing working condition intervals;
step S305, judging whether the working condition point of the engine is in a region ①, if the working condition point of the engine is in a region ①, executing step S306, otherwise executing step S307;
step S306, calculating the accumulated urea crystallization amount in a ① area;
step S307, judging whether the working condition point of the engine is in a region ②, if the working condition point of the engine is in a region ②, executing step S308, otherwise executing step S309;
step S308, calculating the residual moisture amount in ②;
step S309, calculating the residual quantity of urea and water in ③;
and step S310, calculating and summing to obtain the urea crystallization amount and the residual moisture amount.
It should be noted that, reference may be made to the description related to the embodiment shown in fig. 1 for a preferred implementation of the embodiment shown in fig. 3, and details are not described here again.
Compared with the existing urea crystallization calculation method, the urea crystallization calculation method provided by the embodiment of the application has the following advantages:
a plurality of MAP graphs do not need to be calibrated before calculation, the calibration work difficulty is reduced, and a large amount of time can be saved.
The comprehensive working condition is covered, the existing urea crystallization calculation method cannot cover all factors, and the calculation error is large. The method provided by the application can theoretically cover the whole working condition space of the engine, and meanwhile, various factors such as liquid film accumulation (participating in the calculation process of moisture), urea deposition, crystal generation and removal are considered, so that the calculation is accurate, and the calculation efficiency is high.
The method can calculate the urea crystallization amount of transient circulation, can meet the requirement of real-time control, provides effective experimental basis for the control of the post-treatment and anti-crystallization of the engine, reduces the urea crystallization rate and improves the treatment efficiency of the engine mixer.
Fig. 4 is a block diagram of an apparatus for determining an amount of urea crystals in an engine according to an embodiment of the present application, as shown in fig. 4, the apparatus including:
the calibration module 40 is configured to calibrate the exhaust gas temperature and the urea injection amount of the engine according to different exhaust gas flow rates of the engine, so as to obtain multiple sets of calibration values, where each set of calibration value includes the exhaust gas temperature and the urea injection amount.
And the drawing module 42 is configured to draw a control curve graph of the exhaust gas temperature and the urea injection amount according to multiple sets of calibration values, wherein an abscissa of the control curve graph is a value of the exhaust gas temperature, and an ordinate of the control curve graph is a value of the urea injection amount.
A dividing module 44 is configured to divide the control profile into a plurality of operating condition regions.
And the calculating module 46 is used for calculating the urea crystallization amount when the engine works in each working condition region according to the urea crystallization amount calculating method corresponding to each working condition region in the plurality of working condition regions.
It should be noted that, reference may be made to the description related to the embodiment shown in fig. 1 for a preferred implementation of the embodiment shown in fig. 4, and details are not described here again.
The embodiment of the application also provides a storage medium, which comprises a stored program, wherein when the program runs, the device where the storage medium is controlled to execute the method for determining the urea crystallization amount in the engine.
The storage medium stores a program for executing the following functions: calibrating the exhaust temperature and urea injection quantity of the exhaust gas of the engine according to different exhaust gas exhaust flow rates of the engine to obtain multiple groups of calibration values, wherein each group of calibration values comprises the exhaust temperature and the urea injection quantity of the exhaust gas; drawing a control curve graph of exhaust gas temperature and urea injection quantity according to a plurality of groups of calibration values, wherein the abscissa of the control curve graph is the value of the exhaust gas temperature, and the ordinate of the control curve graph is the value of the urea injection quantity; dividing the control curve graph into a plurality of working condition areas; and calculating the urea crystallization amount of the engine working in each working condition region according to the urea crystallization amount calculation method corresponding to each working condition region in the plurality of working condition regions.
Embodiments of the present application also provide a processor for running a program stored in a memory, wherein the program when running performs the above method of determining an amount of urea crystals in an engine.
The processor is used for running a program for executing the following functions: calibrating the exhaust temperature and urea injection quantity of the exhaust gas of the engine according to different exhaust gas exhaust flow rates of the engine to obtain multiple groups of calibration values, wherein each group of calibration values comprises the exhaust temperature and the urea injection quantity of the exhaust gas; drawing a control curve graph of exhaust gas temperature and urea injection quantity according to a plurality of groups of calibration values, wherein the abscissa of the control curve graph is the value of the exhaust gas temperature, and the ordinate of the control curve graph is the value of the urea injection quantity; dividing the control curve graph into a plurality of working condition areas; and calculating the urea crystallization amount of the engine working in each working condition region according to the urea crystallization amount calculation method corresponding to each working condition region in the plurality of working condition regions.
The above-mentioned serial numbers of the embodiments of the present application are merely for description and do not represent the merits of the embodiments.
In the above embodiments of the present application, the descriptions of the respective embodiments have respective emphasis, and for parts that are not described in detail in a certain embodiment, reference may be made to related descriptions of other embodiments.
In the embodiments provided in the present application, it should be understood that the disclosed technology can be implemented in other ways. The above-described embodiments of the apparatus are merely illustrative, and for example, the division of the units may be a logical division, and in actual implementation, there may be another division, for example, multiple units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, units or modules, and may be in an electrical or other form.
The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.
In addition, functional units in the embodiments of the present application may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit.
It should be understood that the technical solutions of the present application, in essence or part of the technical solutions contributing to the prior art, or all or part of the technical solutions, may be embodied in the form of software products stored in a storage medium, which includes several instructions for causing a computer device (which may be a personal computer, a server, a network device, or the like) to execute all or part of the steps of the methods described in the embodiments of the present application.
The foregoing is only a preferred embodiment of the present application and it should be noted that those skilled in the art can make several improvements and modifications without departing from the principle of the present application, and these improvements and modifications should also be considered as the protection scope of the present application.
Claims (11)
1. A method of determining an amount of urea crystallization in an engine, comprising:
calibrating the exhaust temperature and urea injection quantity of the exhaust gas of the engine according to different exhaust gas exhaust flow rates of the engine to obtain multiple groups of calibration values, wherein each group of calibration values comprises the exhaust temperature and urea injection quantity of the exhaust gas;
drawing a control curve graph of the exhaust gas temperature and the urea injection quantity according to the plurality of groups of calibration values, wherein the abscissa of the control curve graph is the value of the exhaust gas temperature, and the ordinate of the control curve graph is the value of the urea injection quantity;
dividing the control curve graph into a plurality of working condition areas;
and calculating the urea crystallization amount of the engine working in each working condition area according to the urea crystallization amount calculation method corresponding to each working condition area in the plurality of working condition areas.
2. The method of claim 1, wherein calibrating the exhaust gas temperature and urea injection amount of the engine according to different exhaust gas flow rates of the engine comprises:
when the exhaust flow of the tail gas is lower than a first preset threshold value, calibrating the exhaust temperature of the tail gas of the engine and the urea injection amount when the temperature in an exhaust pipe of the engine reaches a first preset temperature and a second preset temperature respectively to obtain two groups of calibration values serving as a first group of calibration values;
when the exhaust gas flow rate is higher than a second preset threshold value, calibrating the exhaust gas temperature and the urea injection amount of the engine at the first preset temperature and the second preset temperature respectively to obtain two sets of calibration values as a second set of calibration values.
3. The method of claim 2, wherein plotting the exhaust gas temperature and the urea injection amount against the plurality of sets of calibrations comprises:
performing linear interpolation calculation according to the first group of calibration values to obtain a plurality of control values, and drawing a first control curve according to the plurality of control values calculated by the first group of calibration values;
and performing linear interpolation calculation according to the second group of calibration values to obtain a plurality of control values, drawing a second control curve according to the plurality of control values calculated according to the second group of calibration values, wherein the first control curve and the second control curve jointly form the control curve graph.
4. The method of claim 3, wherein dividing the control profile into a plurality of operating condition regions comprises:
and dividing the control curve chart into three working condition areas according to the residual amounts of the moisture and the urea in the mixer of the engine, wherein the first working condition area is an amorphous area, the second working condition area is a liquid area, and the third working condition area is a crystallization area.
5. The method of claim 4, wherein calculating the urea crystallization amount when the engine operates in each of the plurality of operating condition regions according to the urea crystallization amount calculation method corresponding to each of the operating condition regions respectively comprises:
judging whether the engine works in the non-crystallization area or not;
if the engine is judged to work in the non-crystallization area, detecting whether residual urea exists in an exhaust pipe of the engine;
if the residual urea exists in an exhaust pipe of the engine and no moisture exists, calculating a first urea crystallization amount corresponding to the residual urea according to a first formula;
and if the residual urea does not exist in the exhaust pipe of the engine and moisture exists in the exhaust pipe of the engine, calculating a first moisture residual quantity according to a second formula.
6. The method of claim 5, wherein if it is determined that the engine is not operating in the amorphous region, the method further comprises:
judging whether the engine works in the liquid area or not;
if the engine is judged not to work in the liquid area, the engine is determined to work in the crystallization area, and a second urea crystallization amount is obtained by calculation according to a third formula;
and if the engine is judged to work in the liquid area, calculating according to a fourth formula to obtain a second moisture residual quantity.
7. Method according to claim 5 or 6, characterized in that, after obtaining said first urea crystal quantity, said second urea crystal quantity, said first residual moisture quantity and said second residual moisture quantity, it comprises:
taking the sum of the first urea crystal amount and the second urea crystal amount as a total urea crystal amount in an exhaust pipe of the engine;
taking the sum of the first residual moisture amount and the second residual moisture amount as a total residual moisture amount in an exhaust pipe of the engine.
8. The method of claim 1, wherein prior to calibrating exhaust gas temperature and urea injection amount of the engine, the method further comprises:
initializing the amount of urea crystals and the residual amount of moisture in an exhaust pipe of the engine to zero.
9. An apparatus for determining an amount of urea crystals in an engine, comprising:
the calibration module is used for calibrating the exhaust temperature and urea injection quantity of the exhaust gas of the engine according to different exhaust gas flow rates of the engine to obtain a plurality of groups of calibration values, and each group of calibration values comprises the exhaust temperature and the urea injection quantity of the exhaust gas;
the drawing module is used for drawing a control curve graph of the exhaust temperature of the exhaust gas and the urea injection amount according to the plurality of groups of calibration values, wherein the abscissa of the control curve graph is the value of the exhaust temperature of the exhaust gas, and the ordinate of the control curve graph is the value of the urea injection amount;
the dividing module is used for dividing the control curve graph into a plurality of working condition areas;
and the calculation module is used for calculating the urea crystallization amount when the engine works in each working condition region according to the urea crystallization amount calculation method corresponding to each working condition region in the plurality of working condition regions.
10. A storage medium, characterized in that the storage medium comprises a stored program, wherein the program, when executed, controls an apparatus in which the storage medium is located to perform a method of determining an amount of urea crystals in an engine according to any one of claims 1 to 8.
11. A processor characterized by being configured to run a program stored in a memory, wherein the program is run to perform the method of determining an amount of urea crystals in an engine according to any one of claims 1 to 8.
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