CN113482749A - Method for improving SCR conversion efficiency - Google Patents

Method for improving SCR conversion efficiency Download PDF

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Publication number
CN113482749A
CN113482749A CN202110888836.XA CN202110888836A CN113482749A CN 113482749 A CN113482749 A CN 113482749A CN 202110888836 A CN202110888836 A CN 202110888836A CN 113482749 A CN113482749 A CN 113482749A
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Prior art keywords
scr
temperature sensor
sensor
conversion efficiency
temperature
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CN202110888836.XA
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Chinese (zh)
Inventor
王书伟
张晓斌
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Wuxi Wabertec Co ltd
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Wuxi Wabertec Co ltd
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Priority to CN202110888836.XA priority Critical patent/CN113482749A/en
Publication of CN113482749A publication Critical patent/CN113482749A/en
Pending legal-status Critical Current

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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]
    • 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
    • F01N11/00—Monitoring or diagnostic devices for exhaust-gas treatment apparatus, e.g. for catalytic activity
    • F01N11/002—Monitoring or diagnostic devices for exhaust-gas treatment apparatus, e.g. for catalytic activity the diagnostic devices measuring or estimating temperature or pressure in, or downstream of the exhaust apparatus
    • 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
    • F01N3/02—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust
    • F01N3/021—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters
    • F01N3/033—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters in combination with other devices
    • F01N3/035—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters in combination with other devices with catalytic reactors, e.g. catalysed diesel particulate filters
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/18—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control
    • F01N3/20—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control specially adapted for catalytic conversion ; Methods of operation or control of catalytic converters
    • F01N3/2066—Selective catalytic reduction [SCR]
    • F01N3/208—Control of selective catalytic reduction [SCR], e.g. dosing of reducing agent
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • 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
    • F01N2550/02—Catalytic activity of catalytic converters
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2560/00—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics
    • F01N2560/02—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics the means being an exhaust gas sensor
    • F01N2560/026—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics the means being an exhaust gas sensor for measuring or detecting NOx
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2570/00—Exhaust treating apparatus eliminating, absorbing or adsorbing specific elements or compounds
    • F01N2570/14—Nitrogen oxides
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2610/00—Adding substances to exhaust gases
    • F01N2610/02—Adding substances to exhaust gases the substance being ammonia or urea
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
    • Y02A50/20—Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/12—Improving ICE efficiencies
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/40—Engine management systems

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  • Engineering & Computer Science (AREA)
  • 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)
  • Processes For Solid Components From Exhaust (AREA)

Abstract

The invention discloses a method for improving SCR conversion efficiency, wherein an engine post-treatment assembly and a control unit are installed on a truck, and the engine post-treatment assembly comprises an oxidation catalyst, a diesel particle filter, a urea injection system, an SCR catalyst, a temperature sensor before DOC, a temperature sensor before DPF, a temperature sensor before SCR, a temperature sensor after SCR, a pressure difference sensor, a NOx sensor before DOC, a NOx sensor after SCR, an accelerator position sensor, a throttle position sensor, an environment temperature sensor and an engine cooling water temperature sensor; the control unit comprises a signal alarm module and a regeneration confirmation module. The invention relates to the technical field of SCR conversion efficiency, and particularly provides a method for improving the SCR conversion efficiency.

Description

Method for improving SCR conversion efficiency
Technical Field
The invention relates to the technical field of SCR conversion efficiency of trucks, in particular to a method for improving the SCR conversion efficiency.
Background
At present, trucks running on roads are basically vehicles in the fifth and sixth countries of China, the emission regulation of the sixth country is also implemented at 7-1 month in 2020, the requirements of the emission regulation of the sixth country are clear, and if the emission of the whole vehicle exceeds the requirements of the regulation, the vehicles need to be subjected to a series of operations such as lighting, torque limitation and the like. And reminding a driver to maintain in time. However, the conversion efficiency of the SCR catalyst is reduced for the following reasons.
1: in the domestic market, the national six fuel oil quality of a small gas station is poor, the sulfur content exceeds the standard, the price is low, and in order to reduce the use cost, some drivers use poor-quality diesel oil for a long time, and the problem of low conversion efficiency of the SCR catalyst can occur in the use process.
2: in some low-temperature areas or when the vehicle is not easy to start, a driver can ignite for a long time to start, so that the SCR catalyst is polluted by HC, and the problem of reduction of conversion efficiency of the SCR catalyst can also occur.
3: because the reason of vehicle service condition, for example use in urban area for a long time, the service condition is for stopping, and water temperature and exhaust temperature are all not high, when exhaust temperature near urea start-up point, the conversion efficiency of SCR catalyst itself is not high and ammonia reveals easily this moment, reports out SCR catalyst conversion efficiency low fault easily.
At present, in order to solve the problem of low conversion efficiency of the SCR catalyst, a new part can be replaced only at a maintenance station.
Disclosure of Invention
Aiming at the situation, in order to overcome the defects of the prior art, the invention provides a method for improving the conversion efficiency of an SCR (selective catalytic reduction), which solves the problem of low conversion efficiency of the SCR catalyst caused by over standard sulfur of national fuel oil, THC pollution on hardware of the SCR catalyst, ammonia leakage and the like, ensures that the SCR catalyst can normally work, improves the use reliability of a vehicle, and reduces the maintenance cost of a vehicle owner.
The technical scheme adopted by the invention is as follows: a method for improving SCR conversion efficiency, the truck being equipped with an engine aftertreatment assembly and a control unit, the engine aftertreatment assembly comprising an oxidation catalyst, a diesel particulate filter, a urea injection system, an SCR catalyst, a pre-DOC temperature sensor, a pre-DPF temperature sensor, a pre-SCR temperature sensor, a post-SCR temperature sensor, a differential pressure sensor, a pre-DOC NOx sensor, a post-SCR NOx sensor, a throttle position sensor, an ambient temperature sensor, and an engine cooling water temperature sensor;
the control unit is provided with a signal alarm module and a regeneration confirmation module;
the control unit and the engine aftertreatment are operated in the following modes:
when a vehicle runs normally, when the temperature of a front temperature sensor of an SCR reaches a set urea start-up temperature, a urea injection system starts to inject urea into an SCR catalyst through a nozzle, the urea reacts in the SCR catalyst to react NOx, meanwhile, a front NOx sensor of a DOC, a rear NOx sensor of the SCR, the front temperature sensor of the SCR and a rear temperature sensor of the SCR send real-time signals to a control unit, the control unit processes and calculates the signals through the received signals, when the average conversion efficiency of the SCR catalyst within a period of time obtained through calculation is lower than a set conversion efficiency threshold value, the control unit considers that the conversion efficiency of the SCR catalyst is reduced at the moment after a certain confirmation time, and a signal alarm module reports a fault signal of low conversion efficiency of the SCR;
a regeneration confirmation module in the control unit confirms the cooling water temperature, the throttle opening degree, the temperature before an oxidation catalyst and the temperature before a diesel particle filter meet the limit value and sends a regeneration confirmation signal according to signals provided by a temperature sensor before DOC, a temperature sensor before DPF, a temperature sensor before SCR, a temperature sensor after SCR, a differential pressure sensor, a NOx sensor before DOC, a NOx sensor after SCR, a throttle position sensor, an environment temperature sensor and an engine cooling water temperature sensor;
the control unit enables the inlet temperature of the SCR catalyst to be increased to more than 500 ℃ through regeneration of the diesel particulate filter and continues for a period of time, and then the SCR catalyst with sulfur poisoning and THC pollution is made to react at high temperature to remove sulfide and THC, and the conversion efficiency of the SCR catalyst is recovered.
Further, the urea injection system comprises a urea supply unit, a urea injection unit, a urea liquid level temperature and mass sensor and a urea tank.
Further, the accelerator position sensor and the throttle position sensor are used for detecting the accelerator opening degree.
Further, the differential pressure sensor is used for detecting the amount of carbon accumulated in the diesel particulate filter, when the carbon in the diesel particulate filter changes, the corresponding differential pressure also changes, and at the moment, a signal of the differential pressure sensor is sent to the control unit.
The invention with the structure has the following beneficial effects: the scheme solves the problem of low conversion efficiency of the SCR catalyst caused by over standard sulfur of the national six-fuel oil, THC pollution on SCR hardware, ammonia leakage and the like, ensures that an SCR system can normally work, and improves the use reliability of a vehicle; in the current market, if the problem of low conversion efficiency of the SCR catalyst is found, the sold solution is to replace a new part, clear a fault code by a diagnostic instrument and remove a limit button; according to the scheme of the invention, if the conversion efficiency of the SCR catalyst is reduced by the NOX sensor, the SCR catalyst can be regenerated by the strategy of the invention, and the problem of low efficiency of the SCR catalyst caused by sulfur poisoning, pollution and the like of the SCR catalyst can be solved by the regenerated high temperature.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:
FIG. 1 is a schematic structural view of an engine aftertreatment assembly of a national six-factor light and heavy truck;
FIG. 2 is a schematic diagram illustrating a signal processing flow of a control unit in a method for improving SCR conversion efficiency according to the present invention.
The system comprises an oxidation catalyst 1, a diesel particle filter 2, a urea injection system 3, an SCR catalyst 4, a temperature sensor before DOC 6, a temperature sensor before DPF 7, a temperature sensor before SCR 8, a temperature sensor after SCR 9, a pressure difference sensor 10, a NOx sensor before DOC 11 and a NOx sensor after SCR.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the 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 invention.
As shown in fig. 1-2, the present invention is a method for improving SCR conversion efficiency, the truck being equipped with an engine after-treatment assembly including an oxidation catalyst 1, a diesel particulate filter 2, a urea injection system 3, an SCR catalyst 4, a pre-DOC temperature sensor 5, a pre-DPF temperature sensor 6, a pre-SCR temperature sensor 7, a post-SCR temperature sensor 8, a differential pressure sensor 9, a pre-DOC NOx sensor 10, a post-SCR NOx sensor 11, a throttle position sensor, an ambient temperature sensor, and an engine cooling water temperature sensor, and a control unit;
the control unit is provided with a signal alarm module and a regeneration confirmation module;
the operating modes of the control unit and the engine aftertreatment are as follows:
when a vehicle runs normally, when the temperature of the SCR front temperature sensor 7 reaches a set urea start-up temperature, the urea injection system 3 starts to inject urea into the SCR catalyst 4 through a nozzle, the urea reacts in the SCR catalyst 4 to react NOx, meanwhile, the DOC front NOx sensor 10, the SCR rear NOx sensor 11, the SCR front temperature sensor 7 and the SCR rear temperature sensor 8 send real-time signals to the control unit, the control unit processes and calculates through the received signals, when the average conversion efficiency of the SCR catalyst 4 within a period of time obtained through calculation is lower than a set conversion efficiency threshold value, the control unit considers that the conversion efficiency of the SCR catalyst 4 at the moment is reduced after a certain confirmation time, and the signal alarm module reports an SCR conversion efficiency low fault signal;
a regeneration confirmation module in the control unit confirms the cooling water temperature, the throttle opening degree, the temperature in front of the oxidation catalyst 1 and the temperature in front of the diesel particle filter 2 of the engine according to signals provided by a pre-DOC temperature sensor 5, a pre-DPF temperature sensor 6, a pre-SCR temperature sensor 7, a post-SCR temperature sensor 8, a differential pressure sensor 9, a pre-DOC NOx sensor 10, a post-SCR NOx sensor 11, a throttle position sensor, an environment temperature sensor and an engine cooling water temperature sensor and sends a regeneration confirmation signal after the cooling water temperature, the throttle opening degree, the temperature in front of the oxidation catalyst 1 and the temperature in front of the diesel particle filter 2 meet the limit values;
the control unit enables the inlet temperature of the SCR catalyst 4 to be raised to more than 500 ℃ through regeneration of the diesel particulate filter 2 and continues for a period of time, and then enables the SCR catalyst 4 with sulfur poisoning and THC pollution to react at high temperature to remove sulfide and THC, and the conversion efficiency of the SCR catalyst 4 is recovered.
The urea injection system 3 comprises a urea supply unit, a urea injection unit, a urea liquid level temperature and quality sensor and a urea tank.
The accelerator position sensor and the throttle position sensor are used for detecting the accelerator opening.
The differential pressure sensor 9 is used to detect the amount of accumulated carbon inside the diesel particulate filter 2.
It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, 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.
While there have been shown and described what are at present considered the fundamental principles and essential features of the invention and its advantages, it will be apparent to those skilled in the art that the invention is not limited to the details of the foregoing exemplary embodiments, but is capable of other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.
Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.

Claims (4)

1. A method for improving SCR conversion efficiency, characterized by: the truck is provided with an engine post-processing assembly and a control unit, wherein the engine post-processing assembly comprises an oxidation catalyst, a diesel particle filter, a urea injection system, an SCR catalyst, a temperature sensor before DOC, a temperature sensor before DPF, a temperature sensor before SCR, a temperature sensor after SCR, a differential pressure sensor, a NOx sensor before DOC, a NOx sensor after SCR, an accelerator position sensor, a throttle position sensor, an environment temperature sensor and an engine cooling water temperature sensor;
the control unit is provided with a signal alarm module and a regeneration confirmation module;
the control unit and the engine aftertreatment are operated in the following modes:
when a vehicle runs normally, when the temperature of a front temperature sensor of an SCR reaches a set urea start-up temperature, a urea injection system starts to inject urea into an SCR catalyst through a nozzle, the urea reacts in the SCR catalyst to react NOx, meanwhile, a front NOx sensor of a DOC, a rear NOx sensor of the SCR, the front temperature sensor of the SCR and a rear temperature sensor of the SCR send real-time signals to a control unit, the control unit processes and calculates the signals through the received signals, when the average conversion efficiency of the SCR catalyst within a period of time obtained through calculation is lower than a set conversion efficiency threshold value, the control unit considers that the conversion efficiency of the SCR catalyst is reduced at the moment after a certain confirmation time, and a signal alarm module reports a fault signal of low conversion efficiency of the SCR;
a regeneration confirmation module in the control unit confirms the cooling water temperature, the throttle opening degree, the temperature before an oxidation catalyst and the temperature before a diesel particle filter meet the limit value and sends a regeneration confirmation signal according to signals provided by a temperature sensor before DOC, a temperature sensor before DPF, a temperature sensor before SCR, a temperature sensor after SCR, a differential pressure sensor, a NOx sensor before DOC, a NOx sensor after SCR, a throttle position sensor, an environment temperature sensor and an engine cooling water temperature sensor;
the control unit enables the inlet temperature of the SCR catalyst to be increased to more than 500 ℃ through regeneration of the diesel particulate filter and continues for a period of time, and then the SCR catalyst with sulfur poisoning and THC pollution is made to react at high temperature to remove sulfide and THC, and the conversion efficiency of the SCR catalyst is recovered.
2. A method for improving SCR conversion efficiency according to claim 1, characterized in that: the urea injection system comprises a urea supply unit, a urea injection unit, a urea liquid level temperature and quality sensor and a urea box.
3. A method for improving SCR conversion efficiency according to claim 1, characterized in that: the throttle position sensor and the throttle position sensor are used for detecting the throttle opening.
4. A method for improving SCR conversion efficiency according to claim 1, characterized in that: the differential pressure sensor is used for detecting the amount of accumulated carbon in the diesel particulate filter.
CN202110888836.XA 2021-08-02 2021-08-02 Method for improving SCR conversion efficiency Pending CN113482749A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114033534A (en) * 2021-11-24 2022-02-11 潍柴动力股份有限公司 SCR conversion efficiency recovery method and device and vehicle

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105370355A (en) * 2015-12-16 2016-03-02 潍柴动力股份有限公司 Desulfurization controlling mode for SCR system
CN106401704A (en) * 2016-10-28 2017-02-15 东风商用车有限公司 Sulfur poisoning eliminating device for SCR (selective catalytic reduction) catalyst of diesel engine and using method of sulfur poisoning eliminating device

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105370355A (en) * 2015-12-16 2016-03-02 潍柴动力股份有限公司 Desulfurization controlling mode for SCR system
CN106401704A (en) * 2016-10-28 2017-02-15 东风商用车有限公司 Sulfur poisoning eliminating device for SCR (selective catalytic reduction) catalyst of diesel engine and using method of sulfur poisoning eliminating device

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114033534A (en) * 2021-11-24 2022-02-11 潍柴动力股份有限公司 SCR conversion efficiency recovery method and device and vehicle

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