CN114233445B - Method and device for detecting urea crystals of SCR system - Google Patents

Method and device for detecting urea crystals of SCR system Download PDF

Info

Publication number
CN114233445B
CN114233445B CN202111519361.3A CN202111519361A CN114233445B CN 114233445 B CN114233445 B CN 114233445B CN 202111519361 A CN202111519361 A CN 202111519361A CN 114233445 B CN114233445 B CN 114233445B
Authority
CN
China
Prior art keywords
urea
crystallization
duration
under
urea injection
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN202111519361.3A
Other languages
Chinese (zh)
Other versions
CN114233445A (en
Inventor
张素英
许雪利
薛裕丹
王建东
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Weichai Power Co Ltd
Original Assignee
Weichai Power Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Weichai Power Co Ltd filed Critical Weichai Power Co Ltd
Priority to CN202111519361.3A priority Critical patent/CN114233445B/en
Publication of CN114233445A publication Critical patent/CN114233445A/en
Application granted granted Critical
Publication of CN114233445B publication Critical patent/CN114233445B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • 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
    • 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
    • F01N9/002—Electrical control of exhaust gas treating apparatus of filter regeneration, e.g. detection of clogging
    • 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
    • F01N2550/00—Monitoring or diagnosing the deterioration of exhaust systems
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/12—Improving ICE efficiencies
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/40—Engine management systems

Landscapes

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

Abstract

The application discloses a method for detecting urea crystallization of an SCR system, which comprises the following steps: under different operation conditions, the engine respectively obtains urea injection quantity of the selective catalytic reduction SCR system under each operation condition; different operating conditions correspond to different rotating speeds and torques; determining the duration of the crystallization of the urea according to the urea injection amount; according to the duration time of crystallization of urea under each operation condition, whether DPF regeneration of a diesel particulate filter needs to be triggered during actual operation of an engine is determined, the DPF regeneration is used for eliminating urea crystallization, whether urea crystallization occurs can be accurately judged, and when the urea crystallization occurs, the DPF regeneration is triggered, so that the urea crystallization is eliminated.

Description

Method and device for detecting urea crystals of SCR system
Technical Field
The application relates to the technical field of exhaust emission, in particular to a method and a device for detecting urea crystallization of an SCR system.
Background
In recent years, the basic principle of Selective Catalytic Reduction (SCR) technology is to inject fuel into exhaust gas or add another reducing agent, select an appropriate catalyst, promote the reaction of the reducing agent with NOx, and suppress the oxidation of the reducing agent by oxygen in the exhaust gas. The existing SCR technology can be classified into two types, i.e., urea SCR technology in which NH3 generated by decomposition of urea is used as a reducing agent and hydrocarbon SCR technology in which hydrocarbon is used as a reducing agent, according to the kind of the reducing agent. At present, the hydrocarbon SCR technology is still in further research and is not applied in a large number of fields; the urea SCR technology is mature, and the practical application is more.
DOC-DPF working principle: the DOC can reduce HC, CO, SOF and other substances in the tail gas of the diesel engine, so that the substances can be subjected to oxidation reaction with oxygen in the tail gas at a lower temperature and finally converted into CO 2 And H 2 O, while oxidizing NO in the exhaust gas to NO 2 Sufficient reactants are provided for DPF passive regeneration to achieve high DPF passive regeneration efficiency. During active regeneration, the DOC oxidizes fuel injected from the DPM system to raise the exhaust temperature at the inlet of the DPF, thereby causing active regeneration to occur inside the DPF.
The problem that deposits such as urea crystal stones are easily generated when a diesel vehicle of the SCR system runs under low-load conditions is always a main factor influencing the stable running of the vehicle. During the running process of the vehicle, the sprayed urea liquid drops cannot be converted into NH3 in real time due to poor atomization, uneven mixing or insufficient decomposition of urea, and byproducts are generated, so that the reduction reaction is unstable, and the consistency of NOx emission and the conversion efficiency are affected. The urea sediment can be divided into urea crystal and urea calculus according to the forming process, the urea crystal is generated by the precipitation of supersaturated urea in the urea solution due to the loss of water in the urea solution, is a product in the physical reaction process, and can be continuously decomposed along with the rise of the temperature; the urea calculus is caused by-products generated by side reactions in the urea decomposition process, belongs to chemical reaction products and can be decomposed at a higher temperature. Because the mass of urea liquid drops is much larger than that of gas, crystals formed in the gas flow stagnation area are remained and grow continuously by taking the crystals as pronuclei if the crystals cannot be decomposed completely in time, and urea crystal stones are formed finally due to incomplete decomposition and are accumulated to a certain extent to block a urea flow channel.
Disclosure of Invention
In order to solve the technical problem, the application provides a method and a device for detecting urea crystallization of an SCR system, which can accurately judge whether urea crystallization occurs or not, and trigger DPF regeneration when urea crystallization occurs, so as to eliminate urea crystallization.
In order to achieve the above purpose, the technical solutions provided in the embodiments of the present application are as follows:
the application provides a method for detecting urea crystallization of an SCR system, which comprises the following steps:
under different operation conditions, the engine respectively obtains urea injection quantity of the selective catalytic reduction SCR system under each operation condition; the different operating conditions correspond to different rotating speeds and torques;
determining the duration of crystallization of urea according to the urea injection amount of the SCR system under each operating condition;
determining whether a Diesel Particulate Filter (DPF) regeneration is required to be triggered based on a duration of time that the urea is crystallized under each operating condition, the DPF regeneration being for eliminating urea crystallization.
Preferably, the engine obtains the urea injection amount of the selective catalytic reduction SCR system under each operating condition respectively under different operating conditions, and the method specifically includes:
the urea injection quantity of the SCR system under each rotating speed and each torque is obtained through the universal characteristic curve of the engine under different operating conditions of the engine.
Preferably, the determining whether the actual operation of the engine needs to trigger the regeneration of the diesel particulate filter DPF according to the duration of the crystallization of urea in each operation condition specifically comprises:
according to the maximum duration of urea crystallization under each operating condition;
obtaining a urea crystallization contribution degree under each operation condition according to the maximum duration time of each operation condition, wherein the urea crystallization contribution degree is in inverse proportion to the maximum duration time;
and obtaining the sum of the urea crystallization contribution degrees of all the operation working conditions, and determining that the DPF regeneration needs to be triggered when the sum of the urea crystallization contribution degrees is larger than a preset value.
Preferably, the obtaining of the urea crystallization contribution degree of each operating condition according to the maximum duration of each operating condition specifically includes:
the reciprocal of the maximum duration of each operating condition is obtained as the urea crystallization contribution for each operating condition, respectively.
Preferably, the urea injection amount of the selective catalytic reduction SCR system under each operation condition is obtained respectively, and the duration time of the crystallization of the urea is determined according to the urea injection amount; the method specifically comprises the following steps:
according to the principle that the temperature gradually rises and the urea injection quantity gradually increases under the operation working condition, after the duration time of crystallization of urea of the urea injection quantity at one working condition point is tested, the urea injection is closed, and the rotating speed and the torque of the engine are switched to the next temperature and the next urea injection quantity respectively until the duration time of crystallization of the urea under each operation working condition is obtained.
The application also provides a device for detecting the urea crystallization of the SCR system, which comprises: a urea injection amount obtaining unit, a duration obtaining unit and a judging unit;
the urea injection quantity obtaining unit is used for respectively obtaining the urea injection quantity of the selective catalytic reduction SCR system under each operation condition of the engine under different operation conditions; the different operating conditions correspond to different rotating speeds and torques;
the duration obtaining unit is used for determining the duration of the crystallization of the urea according to the urea injection amount under each operation working condition;
and the judging unit is used for determining whether the DPF regeneration of the diesel particle filter needs to be triggered or not during the actual running of the engine according to the duration of the crystallization of the urea under each running working condition, and the DPF regeneration is used for eliminating the urea crystallization.
Preferably, the urea injection quantity obtaining unit is specifically used for obtaining the urea injection quantity of the SCR system at each rotating speed and torque through a universal characteristic curve of the engine under different operating conditions of the engine.
Preferably, the determination unit is specifically configured to
According to the maximum duration of urea crystallization under each operating condition; obtaining a urea crystallization contribution degree of each operation condition according to the maximum duration of each operation condition, wherein the urea crystallization contribution degree is in inverse proportion to the maximum duration; and obtaining the sum of the urea crystallization contribution degrees of all working conditions, and determining that the DPF regeneration needs to be triggered when the sum of the urea crystallization contribution degrees is larger than a preset value.
Preferably, the determining unit obtains the urea crystallization contribution degree of each operating condition according to the maximum duration of each operating condition, and specifically includes: the reciprocal of the maximum duration of each operating condition is obtained as the urea crystallization contribution for each operating condition, respectively.
Preferably, the duration obtaining unit is specifically configured to, after the duration of occurrence of urea crystallization of the urea injection amount at one operating condition point is tested according to the principle that the temperature gradually increases and the urea injection amount gradually increases, close the urea injection, and switch the rotation speed and the torque of the engine to the next temperature and the next urea injection amount respectively until obtaining the duration of occurrence of urea crystallization of each operating condition.
According to the technical scheme, the method has the following beneficial effects:
according to the method for detecting the urea crystallization of the SCR system, the urea injection amount of the SCR of the engine under each operation condition is obtained, different operation conditions correspond to different urea injection amounts, the duration of the urea crystallization under each urea injection amount is obtained, the urea crystallization contribution degree is obtained according to the duration, the contribution degree is smaller when the duration is longer, whether DPF regeneration is triggered or not is determined according to the urea crystallization contribution degree under all the conditions, and when the DPF regeneration needs to be triggered, the urea crystallization can be eliminated by using high temperature generated by the DPF regeneration, so that the SCR system can normally work.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
FIG. 1 is a schematic illustration of a urea SCR system provided herein;
FIG. 2 is a flowchart of a method for detecting urea crystals in an SCR system according to an embodiment of the present disclosure;
FIG. 3 is a schematic representation of a universal characteristic of an engine provided by an embodiment of the present application;
FIG. 4 is a schematic diagram of a crystallization boundary curve provided in an embodiment of the present application;
FIG. 5 is a schematic diagram of a test sequence of urea crystal boundary test operating condition points provided by an embodiment of the present application;
FIG. 6 is a schematic diagram of an apparatus for detecting urea crystallization in an SCR system provided herein.
Detailed Description
In order to help better understand the scheme provided by the embodiment of the present application, before describing the method provided by the embodiment of the present application, a scenario of an application of the scheme of the embodiment of the present application is described.
Referring to FIG. 1, a schematic diagram of a urea SCR system is provided herein.
As can be seen from the figure, there are included a urea tank 100, a urea supply unit, an engine ECU, a sensor ECU, a urea injection pump, and an SCR.
Because the duration of urea crystallization under different operating conditions is different, the duration of urea crystallization under each operating condition needs to be tested in advance. According to the method, the urea injection amount under all working conditions is obtained through universal characteristic data of the engine, the duration time of urea crystallization under the injection amount is obtained based on the urea injection amount, and therefore the crystallization boundary MAP between the time and the urea injection amount is obtained, whether DPF regeneration needs to be triggered is determined according to the accumulated crystallization contribution degree, and therefore the risk of urea crystallization is avoided.
Referring to FIG. 2, a flow chart of a method for detecting urea crystallization in an SCR system is provided.
The method for detecting urea crystals of the SCR system provided by the embodiment comprises the following steps:
s201: under different operation conditions, the engine respectively obtains urea injection quantity of the selective catalytic reduction SCR system under each operation condition; the different operating conditions correspond to different rotating speeds and torques;
the urea injection amount corresponding to different rotating speeds and different torques is different, so the urea injection amount under each working condition needs to be calibrated.
Specifically, the urea injection amount per rotation speed n and torque T can be obtained from an engine universal characteristic curve, and particularly, refer to fig. 3, which is a schematic diagram of the universal characteristic curve of the engine provided by the application.
The abscissa is the rotational speed n of the engine and the ordinate is the torque T of the engine. Therefore, under different operation conditions of the engine, the urea injection quantity of the SCR system under each rotating speed and each torque can be obtained through the universal characteristic curve of the engine.
S202: the duration of time during which urea crystallization occurs is determined based on the urea injection amount.
For example, the duration of time during which urea crystallizes may be several tens of seconds, or 1 minute.
According to the operating working condition, according to the principle that the temperature gradually rises and the urea injection amount gradually increases, after the duration time that urea of the urea injection amount at one working condition point is crystallized is tested, the urea injection is closed, and the rotating speed and the torque of the engine are switched to the next temperature and the next urea injection amount respectively until the duration time that the urea is crystallized under each operating working condition is obtained.
The urea injection amount may be different for different working conditions, and the time for urea crystallization to occur is different for different temperatures.
S203: and determining whether the actual running of the engine needs to trigger the DPF regeneration of the diesel particulate filter according to the duration of the crystallization of the urea under each running condition, wherein the DPF regeneration is used for eliminating the urea crystallization.
According to the duration of crystallization of urea under each operation condition, determining whether the actual operation of the engine needs to trigger the regeneration of the Diesel Particulate Filter (DPF) or not specifically comprises the following steps:
according to the maximum duration of urea crystallization under each operating condition;
obtaining a urea crystallization contribution degree of each operation condition according to the maximum duration of each operation condition, wherein the urea crystallization contribution degree is in inverse proportion to the maximum duration;
and obtaining the sum of the urea crystallization contribution degrees of all working conditions, and determining that the DPF regeneration needs to be triggered when the sum of the urea crystallization contribution degrees is larger than a preset value.
Referring to fig. 4, a graph of a crystal boundary curve is provided in the examples of the present application.
When the urea injection quantity Q is greater than 0, the crystallization contribution degree of each operation working condition point when the engine operates
Figure BDA0003408188310000061
Where t is the duration of time for which urea crystallization occurs at each operating condition point.
In the actual operation process of the engine, accumulating the crystallization contribution degree as B;
Figure BDA0003408188310000062
where n represents the number of operating points.
When B is larger than or equal to 1, one-time DPF active regeneration needs to be triggered in time, and the generation of urea crystals is eliminated in time through the high temperature generated by DPF regeneration.
The crystallization boundary test requires selecting a test operating point according to the exhaust temperature of the engine and the urea injection amount. The number of the operating points is not less than 30, the selected operating points can cover the exhaust temperature and urea injection amount range in the universal characteristics of the machine types according to the principle of matrix test, the number of the measured temperature levels is not less than 6, and the number of the measured urea injection amount levels is not less than 5. The test sequence of the working condition points generally conforms to the principle of low temperature and high temperature firstly and low injection quantity and high injection quantity secondly, after the crystallization boundary of one working condition point is tested, urea injection is closed, the rotating speed and the torque of the engine are adjusted to be switched to the working condition point with the next temperature and urea injection quantity for crystallization boundary test, and finally, urea crystallization curves at different exhaust temperatures are obtained.
Referring to fig. 5, a schematic diagram of a test sequence for urea crystal boundary test operating point provided herein is shown.
The abscissa of the graph represents the exhaust gas temperature, and the ordinate represents the exhaust gas flow rate.
Taking a 4.6L engine as an example, the exhaust temperature ranges from 190 ℃ to 450 ℃, and the urea injection amount ranges from 40mg/s to 1000mg/s. The exhaust temperature is divided into 6, which are 190 ℃, 210 ℃, 230 ℃, 280 ℃,350 ℃ and 450 ℃ in sequence, and the urea injection amount is divided into 5, and 30 test working condition points are totally. The urea crystallization risk is higher at low temperature, the calibrated urea injection amount is smaller, the corresponding urea injection amount ranges from 30mg/s to 200mg/s under the working condition of low temperature of 190-280 ℃, the corresponding urea injection amount ranges from 300mg/s to 1000mg/s under the working condition of high temperature of 350-450 ℃, and finally crystallization boundary curves corresponding to 6 different exhaust temperatures are drawn.
According to the method provided by the embodiment of the application, the urea injection amount of the SCR of the engine under each operation condition is obtained, different operation conditions correspond to different urea injection amounts, the duration of urea crystallization under each urea injection amount is obtained, the urea crystallization contribution degree is obtained according to the duration, the contribution degree is smaller when the duration is longer, and DPF regeneration is triggered when the sum of the urea crystallization contribution degrees under all the conditions is larger than a preset value, so that urea crystallization can be eliminated by using high temperature generated by DPF regeneration, and the SCR system can work normally.
Based on the method for detecting the urea crystals of the SCR system provided by the embodiment, the application also provides a device for detecting the urea crystals of the SCR system. The following detailed description is made with reference to the accompanying drawings.
Referring to FIG. 6, a schematic diagram of an apparatus for detecting urea crystallization in an SCR system is provided.
The device for detecting urea crystals of the SCR system provided by the embodiment comprises: a urea injection amount obtaining unit 601, a duration obtaining unit 602, and a judging unit 603;
the urea injection quantity obtaining unit 601 is used for obtaining the urea injection quantity of the selective catalytic reduction SCR system under each operating condition of the engine under different operating conditions; the different operating conditions correspond to different rotating speeds and torques;
the duration obtaining unit 602 is configured to determine a duration of time during which urea is crystallized according to the urea injection amount;
the determining unit 603 is configured to determine whether to trigger DPF regeneration of the diesel particulate filter according to a duration of the urea crystallization under each operating condition when the engine actually operates, where the DPF regeneration is used to eliminate the urea crystallization.
And the urea injection quantity obtaining unit is specifically used for obtaining the urea injection quantity of the SCR system under each rotating speed and each torque through a universal characteristic curve of the engine under different operating conditions of the engine.
A determination unit, in particular for
According to the maximum duration of urea crystallization under each operating condition; obtaining a urea crystallization contribution degree of each operation condition according to the maximum duration of each operation condition, wherein the urea crystallization contribution degree is in inverse proportion to the maximum duration; and obtaining the sum of the urea crystallization contribution degrees of all working conditions, and determining that the DPF regeneration needs to be triggered when the sum of the urea crystallization contribution degrees is larger than a preset value.
The judging unit obtains the urea crystallization contribution degree of each operation condition according to the maximum duration of each operation condition, and the judging unit specifically comprises: the reciprocal of the maximum duration of each operating condition is obtained as the urea crystallization contribution for each operating condition, respectively.
And the duration obtaining unit is specifically used for closing urea injection after testing the duration of crystallization of urea in the urea injection amount at one working condition point according to the principle that the temperature gradually rises and the urea injection amount gradually increases under the working condition, and switching the rotating speed and the torque of the engine to the next temperature and the next urea injection amount respectively until obtaining the duration of crystallization of urea under each working condition.
The device that this application embodiment provided obtains the urea injection quantity of engine SCR under every operating mode, different operating modes correspond different urea injection quantities, obtain the duration that urea crystallization appears under every urea injection quantity, obtain urea crystallization contribution degree according to the duration, the contribution degree is the less the longer the duration is, trigger DPF regeneration when urea crystallization contribution degree sum under all operating modes is greater than the default, thereby can utilize the high temperature that DPF regeneration produced to eliminate urea crystallization, make the SCR system can normally work.
From the above description of the embodiments, it is clear to those skilled in the art that all or part of the steps in the method of the above embodiments may be implemented by software plus a necessary general hardware platform. Based on such understanding, the technical solution of the present application may be essentially or partially implemented in the form of a software product, which may be stored in a storage medium, such as a ROM/RAM, a magnetic disk, an optical disk, etc., and includes several instructions for enabling a computer device (which may be a personal computer, a server, or a network communication device such as a media gateway, etc.) to execute the method according to the embodiments or some parts of the embodiments of the present application.
It should be noted that, in the present specification, each embodiment is described in a progressive manner, and each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments may be referred to each other. The method disclosed by the embodiment corresponds to the system disclosed by the embodiment, so that the description is simple, and the relevant points can be referred to the system part for description.
It should also be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising a … …" does not exclude the presence of another identical element in a process, method, article, or apparatus that comprises the element.
The foregoing description of the disclosed embodiments will enable those skilled in the art to make or use the invention in various modifications to these embodiments, which will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (6)

1. A method of detecting urea crystallization in an SCR system, comprising:
under different operation conditions, the engine respectively obtains urea injection quantity of the selective catalytic reduction SCR system under each operation condition; the different operating conditions correspond to different rotating speeds and torques;
determining the duration from the beginning of urea injection to the crystallization of urea according to the urea injection amount of the SCR system under each operation condition;
determining whether a Diesel Particulate Filter (DPF) regeneration needs to be triggered according to the duration from the beginning of the urea injection to the crystallization of the urea under each operating condition, wherein the DPF regeneration is used for eliminating the urea crystallization;
under different operating conditions, the engine respectively obtains the urea injection amount of the selective catalytic reduction SCR system under each operating condition, and the method specifically comprises the following steps:
under different operating conditions, the urea injection quantity of the SCR system under each rotating speed and each torque is obtained through the universal characteristic curve of the engine;
according to the duration from the beginning of urea injection to the crystallization of urea under each operation condition, whether the diesel particulate filter DPF regeneration needs to be triggered during the actual operation of the engine is determined, and the method specifically comprises the following steps:
according to the maximum duration of time that urea starts to be injected to the appearance of crystals under each operating condition;
obtaining a urea crystallization contribution degree under each operation condition according to the maximum duration time of each operation condition, wherein the urea crystallization contribution degree is in inverse proportion to the maximum duration time;
and obtaining the sum of the urea crystallization contribution degrees of all the operation working conditions, and determining that the DPF regeneration needs to be triggered when the sum of the urea crystallization contribution degrees is larger than or equal to a preset value.
2. The method of claim 1, wherein obtaining the urea crystallization contribution for each operating condition based on the maximum duration for each operating condition comprises:
the reciprocal of the maximum duration for each operating condition is obtained separately as the urea crystallization contribution for each operating condition.
3. The method according to claim 1, wherein the urea injection amount of the selective catalytic reduction SCR system under each operating condition is obtained respectively, and the duration from the start of urea injection to the occurrence of urea crystallization is determined according to the urea injection amount, and the method specifically comprises the following steps:
according to the operating working condition, according to the principle that the temperature gradually rises and the urea injection amount gradually increases, after the duration from the urea injection amount of a working condition point to the urea crystallization is tested, the urea injection is closed, the rotating speed and the torque of the engine are switched to the next temperature and the next urea injection amount respectively, and the duration from the urea injection to the urea crystallization is obtained under each operating working condition.
4. An apparatus for detecting urea crystals in an SCR system, comprising: a urea injection amount obtaining unit, a duration obtaining unit and a judging unit;
the urea injection quantity obtaining unit is used for respectively obtaining the urea injection quantity of the selective catalytic reduction SCR system under each operation condition of the engine under different operation conditions; the different operating conditions correspond to different rotating speeds and torques;
the duration obtaining unit is used for obtaining the duration from the beginning of urea injection to the crystallization of urea according to the urea injection quantity under each operation working condition;
the judging unit is used for determining whether the actual running of the engine needs to trigger DPF regeneration of the diesel particulate filter according to the duration from the beginning of the injection of the urea to the crystallization of the urea under each running working condition, and the DPF regeneration is used for eliminating the urea crystallization;
the urea injection quantity obtaining unit is specifically used for obtaining the urea injection quantity of the SCR system under each rotating speed and each torque through a universal characteristic curve of the engine under different operating conditions of the engine;
the judging unit is specifically used for starting to inject urea to the maximum duration time of crystallization according to each operation condition; obtaining a urea crystallization contribution degree of each operation condition according to the maximum duration of each operation condition, wherein the urea crystallization contribution degree is in inverse proportion to the maximum duration; and obtaining the sum of the urea crystallization contribution degrees of all working conditions, and determining that the actual operation of the engine needs to trigger DPF regeneration when the sum of the urea crystallization contribution degrees is greater than or equal to a preset value.
5. The apparatus according to claim 4, wherein the determining unit obtains the urea crystallization contribution for each operating condition according to the maximum duration of each operating condition, and specifically includes: the reciprocal of the maximum duration of each operating condition is obtained as the urea crystallization contribution for each operating condition, respectively.
6. The device according to claim 4, wherein the duration obtaining unit is specifically configured to, after testing the duration from the start of urea injection to the occurrence of urea crystallization of the urea at a working condition point according to the principle that the temperature gradually increases and the urea injection quantity gradually increases, close the urea injection, and switch the engine speed and torque to the next temperature and the next urea injection quantity respectively until obtaining the duration from the start of urea injection to the occurrence of urea crystallization of each working condition.
CN202111519361.3A 2021-12-13 2021-12-13 Method and device for detecting urea crystals of SCR system Active CN114233445B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202111519361.3A CN114233445B (en) 2021-12-13 2021-12-13 Method and device for detecting urea crystals of SCR system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202111519361.3A CN114233445B (en) 2021-12-13 2021-12-13 Method and device for detecting urea crystals of SCR system

Publications (2)

Publication Number Publication Date
CN114233445A CN114233445A (en) 2022-03-25
CN114233445B true CN114233445B (en) 2023-03-21

Family

ID=80755234

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202111519361.3A Active CN114233445B (en) 2021-12-13 2021-12-13 Method and device for detecting urea crystals of SCR system

Country Status (1)

Country Link
CN (1) CN114233445B (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114810306B (en) * 2022-05-09 2023-05-23 潍柴动力股份有限公司 Method, device and processor for determining internal crystallization of selective catalytic reduction device
CN115126579B (en) * 2022-06-29 2024-01-02 潍柴动力股份有限公司 Urea injection quantity control method and vehicle

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111441846A (en) * 2020-03-28 2020-07-24 潍坊势为环保有限公司 Method and device for correcting urea injection amount of SCR (Selective catalytic reduction) system and SCR system
CN112282906A (en) * 2020-10-30 2021-01-29 东风商用车有限公司 SCR catalyst crystallization detection method, detection device and removal device
CN113250800A (en) * 2021-07-06 2021-08-13 南昌碳印环保科技有限公司 Active control method for Urea crystallization risk of Urea-SCR system

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106762058A (en) * 2016-12-26 2017-05-31 潍柴动力空气净化科技有限公司 A kind of method and system for correcting urea injecting quantity
US10253668B2 (en) * 2017-06-20 2019-04-09 Hino Motors, Ltd. Urea SCR system
CN209855885U (en) * 2019-04-12 2019-12-27 无锡威孚力达催化净化器有限责任公司 Control device for removing urea crystals by SCR system
JP2021050701A (en) * 2019-09-26 2021-04-01 いすゞ自動車株式会社 Deposit detection method and exhaust emission control system
CN110725737B (en) * 2019-12-17 2020-05-05 潍柴动力股份有限公司 Urea crystallization state monitoring method of catalytic reduction reaction device and storage medium

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111441846A (en) * 2020-03-28 2020-07-24 潍坊势为环保有限公司 Method and device for correcting urea injection amount of SCR (Selective catalytic reduction) system and SCR system
CN112282906A (en) * 2020-10-30 2021-01-29 东风商用车有限公司 SCR catalyst crystallization detection method, detection device and removal device
CN113250800A (en) * 2021-07-06 2021-08-13 南昌碳印环保科技有限公司 Active control method for Urea crystallization risk of Urea-SCR system

Also Published As

Publication number Publication date
CN114233445A (en) 2022-03-25

Similar Documents

Publication Publication Date Title
CN114233445B (en) Method and device for detecting urea crystals of SCR system
CN110761879B (en) Method and device for controlling urea crystallization, storage medium, and electronic device
US8739517B2 (en) Vehicle-based strategy for removing urea deposits from an SCR catalyst
DE10347132B4 (en) exhaust aftertreatment systems
US8720189B2 (en) Apparatus and method for onboard performance monitoring of oxidation catalyst
US6823663B2 (en) Exhaust gas aftertreatment systems
DE10347130B4 (en) exhaust aftertreatment systems
JP4585787B2 (en) Particulate filter regeneration speed estimation system
US6928806B2 (en) Exhaust gas aftertreatment systems
DE102009011469B4 (en) Fault control strategy for urea SCR NOX reduction at low temperatures
CN101275480B (en) Method and apparatus for exhaust gas purifying using hydrocarbon-selective catalytic reduction
BR112016017664B1 (en) METHOD AND SYSTEM FOR CONTROLLING NITROGEN OXIDE EMISSIONS FROM A COMBUSTION ENGINE
KR101145621B1 (en) Apparatus and method for control ammonia occlusion amount of selective catalytic reduction system
DE10347131A1 (en) exhaust aftertreatment systems
CN112879137B (en) Method and device for evaluating urea crystallization risk based on steady-state working condition
EP2295753B1 (en) Method for urea injection control
CN111396178B (en) Tail gas treatment device, control method and device thereof, and storage medium
CN110454261B (en) HC nozzle blockage monitoring method, device and system
CN110552770A (en) Mixer crystallization detection method and system
CN113356973B (en) Variable frequency pulse type jetting method and related device
CN116146314A (en) Engine aftertreatment temperature control method and device, electronic equipment and medium
CN114941559B (en) Exhaust gas aftertreatment system
WO2013079838A1 (en) Method for optimizing the heating time of an ammonia source for reducing nitrogen oxides
Masoudi et al. A New Electrically Heated Mixer (EHM) for Efficient SCR of NOx in Low Load Cycles
Brzeżański et al. A study on the indirect urea dosing method in the Selective Catalytic Reduction system

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant