CN110295979B - Reducing agent injection control method and device - Google Patents

Reducing agent injection control method and device Download PDF

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Publication number
CN110295979B
CN110295979B CN201910579058.9A CN201910579058A CN110295979B CN 110295979 B CN110295979 B CN 110295979B CN 201910579058 A CN201910579058 A CN 201910579058A CN 110295979 B CN110295979 B CN 110295979B
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nox concentration
nox
scr tank
scr
injection amount
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CN110295979A (en
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张硕
王裕鹏
朱娟
闫立冰
张淑宁
张苏苏
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Weichai Power Co Ltd
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Weichai Power Co Ltd
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • 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
    • 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
    • F01N2550/00—Monitoring or diagnosing the deterioration of exhaust systems
    • 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
    • F01N2610/00—Adding substances to exhaust gases
    • F01N2610/02—Adding substances to exhaust gases the substance being ammonia or urea
    • 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
    • F01N2610/14—Arrangements for the supply of substances, e.g. conduits
    • F01N2610/1453—Sprayers or atomisers; Arrangement thereof in the exhaust apparatus
    • F01N2610/146—Control thereof, e.g. control of injectors or injection valves
    • 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)

Abstract

According to the reducing agent injection control method and device, a first NOx concentration at an outlet position of a first Selective Catalytic Reduction (SCR) box and a second NOx concentration at an outlet position of a second SCR box can be obtained; if NOx emissions of the first SCR tank are determined to be in degradation based on the first NOx concentration and the second NOx concentration, adjusting an amount of injection of reductant into the first SCR tank at least twice based on the first NOx concentration, the second NOx concentration, and a first amount of injection of reductant when the first SCR tank emits the first NOx concentration. According to the invention, the degraded SCR box can be accurately positioned, and the NOx emission is improved by adjusting the injection quantity of the reducing agent of the degraded SCR box, so that the problem of emission degradation can be effectively solved by an injection quantity adjusting mode when a nozzle is blocked, and the concentration of NOx in the exhaust gas can be effectively reduced.

Description

Reducing agent injection control method and device
Technical Field
The invention belongs to the technical field of equipment control, and particularly relates to a reducing agent injection control method and device.
Background
At present, the exhaust gas discharged by an engine is increased along with the increase of the power rotating speed of the engine, in order to reduce the NOx (nitrogen oxide) in the exhaust gas discharged by the engine, the exhaust gas discharged by the engine is equally divided and output to two SCR (Selective Catalytic Reduction) boxes, at least two nozzles are arranged on the SCR boxes, reducing agents (such as urea aqueous solution) are injected into the SCR boxes through the nozzles arranged on the SCR boxes, and the concentration of the NOx in the exhaust gas is reduced through the action of the reducing agents.
However, this method of adding the SCR tank and adding the nozzle may cause a problem of deterioration of emission due to clogging of the nozzle.
Disclosure of Invention
In view of the above, an object of the present invention is to provide a reducing agent injection control method for controlling an injection amount of a reducing agent of an SCR tank to improve NOX emission of the SCR tank in a state where NOX emission of the SCR tank is deteriorated. The technical scheme is as follows:
a reducing agent injection control method comprising:
obtaining a first NOx concentration at an outlet position of a first SCR tank and a second NOx concentration at an outlet position of a second SCR tank;
if NOx emissions of the first SCR tank are determined to be in degradation based on the first NOx concentration and the second NOx concentration, adjusting an amount of injection of reductant into the first SCR tank at least twice based on the first NOx concentration, the second NOx concentration, and a first amount of injection of reductant when the first SCR tank emits the first NOx concentration.
Optionally, if it is determined that the NOX emission of the first SCR tank is under degradation based on the first NOX concentration and the second NOX concentration, adjusting the injection amount of the reducing agent of the first SCR tank at least twice based on the first NOX concentration, the second NOX concentration, and a first injection amount of the reducing agent when the first SCR tank emits the first NOX concentration includes:
obtaining an absolute value of a difference between the first NOx concentration and the second NOx concentration;
if the absolute difference value is larger than the maximum absolute difference value corresponding to the current working condition of the engine to which the first SCR tank belongs and the first NOx concentration is larger than the second NOx concentration, determining that the NOx emission of the first SCR tank is in degradation, and adjusting the injection quantity of the reducing agent of the first SCR tank based on the first NOx concentration, the second NOx concentration and the first injection quantity;
obtaining a third NOx concentration at an outlet position of the first SCR tank under the action of the reducing agent of the adjusted injection amount;
adjusting an injection amount of reductant of the first SCR tank to the first injection amount if it is determined that NOx emissions of the first SCR tank are still in degradation based on the third NOx concentration and the first NOx concentration;
adjusting an injection amount of reductant of the first SCR tank based on the third NOx concentration, second NOx concentration, and the first injection amount if NOx emission of the first SCR tank is determined to be improving based on the third NOx concentration and the first NOx concentration.
Optionally, the adjusting the injection amount of the reductant of the first SCR tank based on the first NOX concentration, the second NOX concentration, and the first injection amount includes:
deriving a compensation factor based on the first NOx concentration and the second NOx concentration;
adjusting an injection amount of reductant of the first SCR tank at a time based on the first injection amount and the compensation factor.
Optionally, the adjusting the injection amount of reductant of the first SCR tank to the first injection amount if it is determined that NOX emission of the first SCR tank is still in degradation based on the third NOX concentration and the first NOX concentration comprises:
determining that NOx emissions of the first SCR tank are still in degradation if the third NOx concentration is greater than or equal to the first NOx concentration;
adjusting an injection amount of the reducing agent of the first SCR tank to the first injection amount.
Optionally, if it is determined that NOx emissions of the first SCR tank are improving based on the third NOx concentration and the first NOx concentration, adjusting an injection amount of the reductant of the first SCR tank based on the third NOx concentration, the second NOx concentration, and the first injection amount comprises:
determining that the NOx emission of the first SCR tank is in improvement if the absolute value of the difference between the third NOx concentration and the second NOx concentration is greater than the maximum absolute value of the difference corresponding to the current working condition of the engine to which the first SCR tank belongs, but the third NOx concentration is less than the first NOx concentration;
deriving a current compensation factor based on the third NOx concentration and the second NOx concentration;
deriving a second injection quantity based on the first injection quantity, a current compensation factor, and a previous compensation factor, the previous compensation factor derived based on a previous NOx concentration of the first SCR tank and the second NOx concentration;
adjusting an injection amount of the reducing agent of the first SCR tank to the second injection amount;
obtaining a fourth NOX concentration at an outlet position of the first SCR tank under the influence of the second injected amount of reductant;
if the absolute value of the difference between the fourth NOx concentration and the second NOx concentration is smaller than or equal to the maximum absolute value of the difference corresponding to the current working condition of the engine to which the first SCR tank belongs, maintaining the injection quantity of the reducing agent of the first SCR tank as the second injection quantity;
and if the absolute value of the difference between the fourth NOx concentration and the second NOx concentration is larger than the maximum absolute value of the difference, but the fourth NOx concentration is smaller than the third NOx concentration, taking the fourth NOx concentration as the third NOx concentration, and returning to the step of obtaining the current compensation factor based on the third NOx concentration and the second NOx concentration.
Optionally, the method further includes:
obtaining an operating state of a first NOx sensor corresponding to the first NOx concentration and an operating state of a second NOx sensor corresponding to the second NOx concentration;
the step of obtaining a first NOx concentration at an exit location of a first Selective Catalytic Reduction (SCR) tank and a second NOx concentration at an exit location of a second SCR tank is performed if an operating state of the first NOx sensor is a normal state and an operating state of the second NOx sensor is a normal state.
A reducing agent injection control device, the device comprising:
an obtaining module to obtain a first NOx concentration at an exit position of a first SCR tank and a second NOx concentration at an exit position of a second SCR tank;
an adjustment module to adjust an injection amount of reductant to the first SCR tank at least twice based on the first NOx concentration, the second NOx concentration, and a first injection amount of reductant at which the first SCR tank emits the first NOx concentration if NOx emission of the first SCR tank is determined to be degrading based on the first NOx concentration and the second NOx concentration.
Optionally, the adjusting module includes:
a first obtaining unit configured to obtain an absolute value of a difference between the first NOX concentration and the second NOX concentration;
a first adjusting unit, configured to, if the absolute difference value is greater than a maximum absolute difference value corresponding to a current operating condition of an engine to which the first SCR tank belongs and the first NOX concentration is greater than the second NOX concentration, determine that NOX emission of the first SCR tank is in degradation, adjust an injection amount of a reducing agent of the first SCR tank based on the first NOX concentration, the second NOX concentration, and the first injection amount;
a second obtaining unit, which is also used for obtaining a third NOx concentration of the outlet position of the first SCR tank under the action of the reducing agent of the adjusted injection quantity;
a second adjusting unit for adjusting the injection amount of the reducing agent of the first SCR tank to the first injection amount if it is determined that the NOx emission of the first SCR tank is still in deterioration based on the third NOx concentration and the first NOx concentration;
a third adjusting unit further configured to adjust an injection amount of the reducing agent of the first SCR tank based on the third NOx concentration, the second NOx concentration, and the first injection amount if it is determined that NOx emission of the first SCR tank is improving based on the third NOx concentration and the first NOx concentration.
Optionally, the first adjusting unit is specifically configured to obtain a compensation factor based on the first NOX concentration and the second NOX concentration; adjusting an injection amount of reductant of the first SCR tank at a time based on the first injection amount and the compensation factor.
Optionally, the second adjusting unit is specifically configured to determine that NOX emission of the first SCR tank is still in degradation if the third NOX concentration is greater than or equal to the first NOX concentration; adjusting an injection amount of the reducing agent of the first SCR tank to the first injection amount.
Optionally, the third adjusting unit includes:
a first determining subunit, configured to determine that NOX emission of the first SCR tank is under improvement if an absolute value of a difference between the third NOX concentration and the second NOX concentration is greater than a maximum absolute value of a difference corresponding to a current operating condition of an engine to which the first SCR tank belongs, but the third NOX concentration is less than the first NOX concentration;
a first obtaining subunit configured to obtain a current compensation factor based on the third NOX concentration and the second NOX concentration;
a first adjusting subunit for deriving a second injection quantity based on the first injection quantity, a current compensation factor, and a previous compensation factor, the previous compensation factor being derived based on a previous NOx concentration of the first SCR tank and the second NOx concentration;
a second adjustment subunit configured to adjust an injection amount of the reducing agent of the first SCR tank to the second injection amount;
a second obtaining subunit configured to obtain a fourth NOX concentration at an outlet position of the first SCR tank by a second injection amount of the reducing agent;
a third adjusting subunit, configured to maintain the injection amount of the reducing agent in the first SCR tank as the second injection amount if an absolute value of a difference between the fourth NOX concentration and the second NOX concentration is less than or equal to a maximum absolute value of a difference corresponding to a current operating condition of an engine to which the first SCR tank belongs;
a third obtaining sub-unit configured to trigger the first obtaining sub-unit with the fourth NOX concentration as the third NOX concentration if an absolute value of a difference between the fourth NOX concentration and the second NOX concentration is larger than the maximum absolute value of the difference, but the fourth NOX concentration is smaller than the third NOX concentration.
Optionally, the apparatus further comprises:
and the state obtaining module is used for obtaining the working state of a first NOx sensor corresponding to the first NOx concentration and the working state of a second NOx sensor corresponding to the second NOx concentration, and if the working state of the first NOx sensor is a normal state and the working state of the second NOx sensor is a normal state, the obtaining module is triggered.
A storage medium having stored therein computer-executable instructions that, when loaded and executed by a processor, carry out a reductant injection control method as claimed in any preceding claim.
Compared with the prior art, the technical scheme provided by the invention has the following advantages: the degraded SCR box is accurately positioned, NOx emission is improved by adjusting the injection amount of the reducing agent of the degraded SCR box, so that the problem of emission degradation can be effectively solved by an injection amount adjusting mode when a nozzle is blocked, and the concentration of NOx in exhaust gas can be effectively reduced.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings 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 invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
FIG. 1 is a schematic flow chart of a reductant injection control method provided by an embodiment of the present invention;
FIG. 2 is a schematic flow chart of another reductant injection control method provided by an embodiment of the present invention;
FIG. 3 is a schematic flow chart of a method for adjusting injection quantity according to an embodiment of the present invention;
FIG. 4 is a schematic flow chart diagram illustrating yet another reductant injection control method provided by an embodiment of the present invention;
FIG. 5 is a schematic structural diagram of a reducing agent injection control device according to an embodiment of the present invention;
FIG. 6 is a schematic structural diagram of another reductant injection control device provided in an embodiment of the present invention;
fig. 7 is a schematic structural diagram of a reducing agent injection control device according to still another embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, 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 some, but not all, embodiments of the present invention. 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, a reducing agent injection control method according to an embodiment of the present invention may include:
s100, obtaining a first NOx concentration of an outlet position of a first SCR box and a second NOx concentration of an outlet position of a second SCR box;
the first SCR box and the second SCR box are positioned in the same engine, and exhaust gas emitted by the engine is divided into the first SCR box and the second SCR box so as to perform chemical action on the exhaust gas in the two SCR boxes to reduce the concentration of NOx in the exhaust gas.
In the embodiment of the invention, the first NOx concentration and the second NOx concentration of the outlet positions can be obtained through NOx sensors at the outlet positions of the first SCR box and the second SCR box, and the two NOx concentrations are used for judging whether one SCR box with degraded NOx emission exists in the two SCR boxes. Whether NOx emissions of the first SCR tank or the second SCR tank are in degradation is determined, for example, by the first NOx concentration and the second NOx concentration.
S200, if the NOx emission of the first SCR tank is determined to be in degradation based on the first NOx concentration and the second NOx concentration, adjusting the injection amount of the reducing agent to the first SCR tank at least twice based on the first NOx concentration, the second NOx concentration and the first injection amount of the reducing agent when the first SCR tank emits the first NOx concentration.
It can be understood that: under the current working condition of the engine, the amount of exhaust gas evenly distributed to the first SCR tank and the second SCR tank is the same, and the injection amounts of reducing agents of the two SCR tanks are close to each other, so that the first NOx concentration and the second NOx concentration are consistent or close to each other (if the absolute value of the difference value of the two NOx concentrations is smaller than a preset threshold value). When the first NOx concentration is inconsistent with the second NOx concentration or the difference is large (for example, the absolute value of the difference between the two NOx concentrations is larger than the maximum absolute value of the difference between the two NOx concentrations in the current working condition), the SCR tank with degraded NOx emission exists in the first SCR tank and the second SCR tank. To the extent that the first NOx concentration does not coincide with the second NOx concentration, the SCR tank having NOx emissions that are in degradation is determined, as will be described with reference to the figures.
The points to be explained are: the reason that the first NOX concentration is inconsistent with the second NOX concentration or has a large difference is that the SCR box is unstable and the time when the situation occurs is less than the preset time, and no adjustment is needed at this time.
For example: if it is determined that the NOx emission of the first SCR tank is degrading, embodiments of the present invention may adjust an injection amount of the reducing agent for the first SCR tank based on the first NOx concentration, the second NOx concentration, and a first injection amount of the reducing agent at which the first SCR tank emits the first NOx concentration. It will be appreciated that adjusting the first NOX concentration to coincide with the second NOX concentration may be difficult to achieve with one adjustment, and therefore may require at least two adjustments of the reductant of the first SCR tank.
The preset threshold, the preset time and the preset duration may be determined according to actual requirements, which is not limited in this embodiment.
According to the technical scheme, the reducing agent injection control method provided by the embodiment of the invention can obtain the first NOx concentration of the outlet position of the first SCR tank and the second NOx concentration of the outlet position of the second SCR tank; if the NOx emission of the first SCR box is determined to be in degradation based on the first NOx concentration and the second NOx concentration, the injection amount of the reducing agent to the first SCR box is adjusted at least twice based on the first NOx concentration, the second NOx concentration and the first injection amount of the reducing agent when the first SCR box emits the first NOx concentration, when one of the two SCR boxes is in degradation due to blockage of the nozzle, the degraded SCR box can be accurately positioned through the NOx concentrations of the two SCR boxes, the NOx emission is improved by adjusting the injection amount of the reducing agent of the degraded SCR box, therefore, the problem of degradation in emission can be effectively solved through an injection amount adjusting mode when the nozzle is blocked, and further, the NOx concentration in the exhaust gas can be effectively reduced.
Alternatively, as shown in fig. 2, in another reductant injection control method provided in the embodiment of the present invention, step S200 may include:
s210, obtaining a difference absolute value of the first NOx concentration and the second NOx concentration;
after obtaining the first NOX concentration and the second NOX concentration, the absolute value of the difference between the first NOX concentration and the second NOX concentration is calculated, and the absolute value of the difference is adopted because the NOX concentration of each SCR tank is not recorded in the operating condition table for recording the standard parameters of the current operating condition of the engine, but the absolute value of the difference between the NOX concentrations of the two SCR tanks is recorded, and therefore the absolute value of the difference is calculated instead of the difference. Since the first NOx concentration should be consistent with or close to the second NOx concentration under the same operating condition, the difference in catalytic reduction between the first SCR tank and the second SCR tank may be reflected by the absolute value of the difference between the first NOx concentration and the second NOx concentration.
S220, if the absolute value of the difference is larger than the maximum absolute value of the difference corresponding to the current working condition of the engine to which the first SCR tank belongs and the first NOx concentration is larger than the second NOx concentration, and the NOx emission of the first SCR tank is determined to be in degradation, adjusting the injection quantity of the reducing agent of the first SCR tank based on the first NOx concentration, the second NOx concentration and the first injection quantity;
under the current working condition of the engine, if the absolute value of the difference value between the first NOx concentration and the second NOx concentration is larger than the maximum absolute value of the difference value corresponding to the current working condition, the SCR tank with degraded NOx emission exists in the first SCR tank and the second SCR tank.
It should be noted that the absolute value of the maximum difference corresponding to different working conditions is different, for example, when the working condition is 3000r/min (rpm), the absolute value of the corresponding maximum difference may be 5; when the working condition is 5000r/min (revolutions per minute), the corresponding maximum difference absolute value can be 8. The maximum difference absolute values corresponding to different working conditions can be obtained by testing the engine before the engine leaves a factory, the maximum difference absolute values are recorded in a working condition table of the engine, and the working condition table records standard parameters under any working condition, so that when the current working condition of the engine is obtained, the standard parameters corresponding to the current working condition can be searched from the working condition table, and then the maximum difference absolute values are obtained from the standard parameters, and the maximum difference absolute values corresponding to the current working condition are important indexes for measuring whether all SCR boxes of the engine normally operate under the current working condition.
According to the embodiment of the invention, after the absolute value of the difference between the first NOx concentration and the second NOx concentration under the current working condition is larger than the maximum absolute value of the difference corresponding to the current working condition, the SCR box with the higher NOx concentration in the first SCR box and the second SCR box is determined as the SCR box with the degraded NOx emission. For example, if the absolute value of the difference between the first NOx concentration and the second NOx concentration of the current operating condition is 7 and is greater than the maximum absolute value of the difference 5 corresponding to the current operating condition, where the first NOx concentration is 75mol/L (moles/liter) and the second NOx concentration is 50mol/L (moles/liter), the NOx emission of the first SCR tank is determined to be in degradation.
In this embodiment, if it is determined that NOx emissions from the first SCR tank are degrading, the amount of reductant injected from the first SCR tank may be adjusted based on the first NOx concentration, the second NOx concentration, and the first injection amount, and the adjusting may include: deriving a compensation factor based on the first NOx concentration and the second NOx concentration; adjusting an injection amount of reductant of the first SCR tank at a time based on the first injection amount and the compensation factor.
Specifically, the compensation factor may be a ratio of the first NOX concentration to the second NOX concentration, and assuming that the first NOX concentration is Ra, the second NOX concentration is Rb, and Ra is greater than Rb, the compensation factor N is Ra/Rb. For example, the first NOx concentration is 75mol/L (moles/liter) and the second NOx concentration is 50mol/L (moles/liter), which are compared to each other to obtain a compensation factor of 1.5.
And the manner of adjusting the injection amount based on the first injection amount and the compensation factor may be, but is not limited to: the injection quantity of the reducing agent in the first SCR tank is adjusted based on the product of the first injection quantity and the compensation factor, specifically, the product of the first injection quantity and the compensation factor is used as the adjusted injection quantity, and when the ratio of the first NOx concentration to the second NOx concentration is used as the compensation factor, the value of the compensation factor is larger than 1, so that the adjustment of the first SCR tank can increase the injection quantity of the reducing agent in the first SCR tank. For example, if the first injection amount of the reducing agent when the first SCR tank emits the first NOX concentration is 30mol/L (mol/L) and the value obtained by multiplying the first injection amount by the compensation factor 1.5 is 45mol/L (mol/L), the injection amount of the reducing agent in the first SCR tank is adjusted to 45mol/L (mol/L).
S230, acquiring a third NOx concentration at the outlet position of the first SCR tank under the action of the reducing agent of the adjusted injection quantity;
specifically, after the injection amount of the reducing agent of the first SCR tank is adjusted according to a value obtained by multiplying the first injection amount of the reducing agent by the compensation factor when the first SCR tank emits the first NOX concentration, the adjusted third NOX concentration at the outlet position of the first SCR tank is obtained. In general, the NOX concentration at the outlet position of the first SCR tank changes after the injection amount of the reducing agent in the first SCR tank is adjusted. For example: when the first injection amount of the reducing agent of the first SCR tank is 10mol/L, the first NOX concentration emitted may be 80mol/L, and after the injection amount of the reducing agent of the first SCR tank is adjusted to 30mol/L, the third NOX concentration emitted by the first SCR tank may be 50 mol/L.
S240, if the NOx emission of the first SCR tank is determined to be still in degradation based on the third NOx concentration and the first NOx concentration, adjusting the injection quantity of the reducing agent of the first SCR tank to the first injection quantity;
that is, the NOx emissions of the first SCR tank that are still in degradation are determined relative to the NOx emissions of the first SCR tank before the adjustment (i.e., the first NOx concentration) and the NOx emissions of the first SCR tank after the adjustment (i.e., the third NOx concentration), thus demonstrating that the adjustment does not function to improve emissions. For example, if the first NOX concentration is 50mol/L (mol/L) and the third NOX concentration after adjusting the injection amount of the reducing agent is 80mol/L (mol/L), the NOX emission of the first SCR tank after adjustment is more deteriorated, which is contrary to the technical problem of reducing the NOX concentration emitted by the first SCR tank according to the embodiment of the present invention. In this case, the embodiment of the invention can adjust the injection quantity of the reducing agent adjusted by the first SCR tank back to the first injection quantity, thereby avoiding waste of the reducing agent.
The manner of determining whether the NOx emissions of the first SCR tank are further degraded in the embodiments of the present invention may be, but is not limited to: determining whether a third NOx concentration is greater than or equal to a first NOx concentration, and if the third NOx concentration is greater than or equal to the first NOx concentration, determining that NOx emissions of the first SCR tank are still in degradation.
It can be appreciated that an object of an embodiment of the present invention is to adjust the injection amount of the reducing agent in the first SCR tank such that the adjusted third NOX concentration in the first SCR tank is less than the first NOX concentration, and when the third NOX concentration is greater than the first NOX concentration, it can be determined that the NOX emission of the first SCR tank is further deteriorated after the adjustment of the injection amount of the reducing agent in the first SCR tank, and therefore it is necessary to adjust the injection amount of the reducing agent in the first SCR tank back to the first injection amount.
S250, if the NOx emission of the first SCR tank is determined to be improving based on the third NOx concentration and the first NOx concentration, adjusting the injection amount of the reducing agent of the first SCR tank based on the third NOx concentration, the second NOx concentration and the first injection amount.
The same way of improving or not is similar to the above-described way of determining whether or not there is further deterioration: and judging whether the third NOx concentration is greater than or equal to the first NOx concentration, and if the third NOx concentration is smaller than the first NOx concentration, determining that the NOx emission of the first SCR tank is under improvement, wherein at the moment, the injection quantity of the reducing agent of the first SCR tank can be continuously adjusted according to the third NOx concentration, the second NOx concentration and the first injection quantity. Referring to fig. 3, the adjustment process may include:
s251, if the absolute value of the difference between the third NOx concentration and the second NOx concentration is larger than the maximum absolute value of the difference corresponding to the current working condition of the engine to which the first SCR tank belongs, but the third NOx concentration is smaller than the first NOx concentration, determining that the NOx emission of the first SCR tank is in improvement;
specifically, when the absolute value of the difference between the third NOX concentration and the second NOX concentration is greater than the maximum absolute value of the difference corresponding to the current operating condition of the engine in which the first SCR tank is located, it indicates that the NOX emission of the first SCR tank after the injection amount of the reducing agent is adjusted is still in degradation, but the third NOX concentration is smaller than the first NOX concentration, that is, the absolute value of the difference between the third NOX concentration and the second NOX concentration is smaller than the absolute value of the difference between the first NOX concentration and the second NOX concentration, so it can be indicated that the NOX emission of the first SCR tank is in improvement before the injection amount of the reducing agent is not adjusted.
For example, the second NOX concentration is 50mol/L and the maximum absolute value of the difference corresponding to the current operating condition of the engine in which the first SCR tank is located is 3, the first NOX concentration obtained before the injection amount of the reducing agent in the first SCR tank is adjusted is 90mol/L, and after the injection amount of the reducing agent in the first SCR tank is adjusted, the third NOX concentration obtained in the first SCR tank is 60mol/L although the absolute value of the difference between the third NOX concentration 60mol/L and the second NOX concentration 50mol/L is greater than 5 and the third NOX concentration 60mol/L is smaller than the first NOX concentration 90mol/L, which means that after the injection amount of the reducing agent in the first SCR tank is adjusted, the NOX emission of the first SCR tank is in improvement compared to before the adjustment, however, since the first SCR tank is still in a deteriorated state with respect to the second SCR tank, it is necessary to continuously adjust the injection amount of the reducing agent in the first SCR tank in addition to the injection amount of the reducing agent when the first SCR tank discharges the third NOX concentration. The continued adjustment process is as follows:
s252, obtaining a current compensation factor based on the third NOx concentration and the second NOx concentration;
specifically, the current compensation factor may be a ratio of the third NOx concentration and the second NOx concentration. The process of obtaining the current compensation factor based on the third NOX concentration and the second NOX concentration is the same as the method of obtaining the compensation factor based on the first NOX concentration and the second NOX concentration, and the detailed description is referred to the above, and will not be repeated herein.
S253, obtaining a second injection quantity based on the first injection quantity, a current compensation factor and a previous compensation factor, wherein the previous compensation factor is obtained based on the previous NOx concentration of the first SCR tank and the second NOx concentration;
for ease of understanding, the following is exemplified here: if the first injection amount of the reducing agent is 60mol/L (mol/L) when the second NOx concentration is 50mol/L (mol/L), the first SCR tank discharges 90mol/L (mol/L) of the first NOx concentration, the compensation factor obtained based on the first NOx concentration and the second NOx concentration is 1.5, the injection amount of the reducing agent of the first SCR tank is 90mol/L (mol/L) after the first injection amount of the reducing agent of the first SCR tank is adjusted to 60mol/L (mol/L), if the third NOx concentration obtained when the injection amount of the reducing agent of the first SCR tank is 90mol/L (mol/L) is 60mol/L (mol/L), the current compensation factor obtained based on the third NOx concentration and the second NOx concentration is 1.2, the second injection amount is 60mol/L (mol/L) multiplied by the compensation factor 1.5, and then multiplied by the current 162mol value of the compensation factor 1.2 L (mol/L).
S254, adjusting the injection quantity of the reducing agent in the first SCR tank to the second injection quantity;
s255, obtaining a fourth NOx concentration at the outlet position of the first SCR tank under the action of the reducing agent with the second injection amount;
s256, if the absolute value of the difference between the fourth NOx concentration and the second NOx concentration is smaller than or equal to the absolute value of the maximum difference corresponding to the current working condition of the engine to which the first SCR tank belongs, maintaining the injection quantity of the reducing agent in the first SCR tank as the second injection quantity;
specifically, when the absolute value of the difference between the fourth NOX concentration and the second NOX concentration at the outlet of the first SCR tank is smaller than or equal to the maximum absolute value of the difference corresponding to the current operating condition of the engine to which the first SCR tank belongs, it is indicated that the NOX emission of the first SCR tank is substantially consistent with the NOX emission of the second SCR tank, and the NOX emission of the first SCR tank returns to normal, so that the second injection amount of the reducing agent when the first SCR tank emits the fourth NOX concentration is maintained without changing the current operating condition after the NOX emission of the first SCR tank returns to normal.
S257, if the absolute value of the difference between the fourth NOX concentration and the second NOX concentration is greater than the maximum absolute value of the difference, but the fourth NOX concentration is less than the third NOX concentration, the fourth NOX concentration is taken as the third NOX concentration, and the step of obtaining the current compensation factor based on the third NOX concentration and the second NOX concentration, i.e., step S252, is returned to perform the repeated adjustment of the injection amount of the reducing agent in the first SCR tank until the NOX emission of the first SCR tank returns to normal.
It can be understood that if the absolute value of the difference between the fourth NOX concentration and the second NOX concentration is still greater than the maximum absolute value of the difference, but the fourth NOX concentration is less than the third NOX concentration, it indicates that the NOX emission of the first SCR tank continues to be improved, so that it is necessary to continue to adjust the injection amount of the reducing agent in the first SCR tank based on the fourth NOX concentration again, and the adjustment process may be to return to step S252 with the fourth NOX concentration as the third NOX concentration.
In order to understand the technical solutions of the embodiments of the present invention as a whole, the following embodiments are further illustrated herein: initially, assuming that the first NOX concentration of the first SCR tank is Ra0 and the first injection amount is MFa0, the second NOX concentration of the second SCR tank is Rb, and Ra0 is greater than Rb, the absolute value of the maximum difference corresponding to the current operating condition is Rmax, and the absolute value of the difference obtained by Ra0 and Rb is R0, on the basis:
when R0 is larger than Rmax, adjusting the injection amount of the reducing agent in the first SCR tank, wherein the compensation factor N0 is Ra0/Rb, adjusting the injection amount of the reducing agent in the first SCR tank to MFa1, and adjusting MFa1 to MFa N0, and obtaining a third NOx concentration Ra1 of the first SCR tank when the injection amount of the reducing agent is MFa 1;
if Ra1 is greater than or equal to Ra0, indicating that degradation is still occurring, maintaining the injected quantity of reductant for the first SCR tank at MFa 0; if Ra1 is smaller than Ra0 and the absolute value of the difference R1 between Ra1 and Rb is greater than Rmax, indicating that improvement is underway, the injection amount of the reducing agent in the first SCR tank is adjusted to MFa2, where MFa2 is MFa N0N 1 and N1 is Ra1/Rb, that is, adjustment based on the compensation factor N0 of the first adjustment is required in the second adjustment; further obtaining a fourth NOX concentration Ra2 of the first SCR tank at an injection quantity of the reducing agent MFa 2;
maintaining an injected amount of reductant of the first SCR tank at MFa1 if Ra2 is greater than or equal to Ra 0; if Ra2 is smaller than Ra1 and the absolute value of the difference R2 between Ra2 and Rb is larger than Rmax, adjusting the injection amount of the reducing agent in the first SCR tank to MFa3, wherein MFa3 ═ MFa × N0 × N1 × N2 and N2 ═ Ra2/Rb, and obtaining the NOX concentration Ra3 of the first SCR tank when the injection amount of the reducing agent is MFa 3;
and so on: maintaining an injected quantity of reductant of the first SCR tank at MFa (i-1) if Rai is greater than or equal to Ra 0; if Rai is less than Ra0, and the absolute value Ri of the difference between Rai and Rb is greater than Rmax, adjusting the injection amount of the reducing agent in the first SCR tank to MFa (i +1), wherein MFa (i +1) ═ MFa N0 × N1 × N2.. Ni, wherein Ni ═ Rai/Rb, and obtaining the NOX concentration Ra (i +1) of the first SCR tank when the injection amount of the reducing agent is MFa (i + 1); if Rai is smaller than Ra0, and the absolute value Ri of the difference obtained by Rai and Rb is not larger than Rmax, the injection quantity of the reducing agent in the first SCR tank is maintained to be MFai;
through repeated adjustment of the injection quantity of the reducing agent in the first SCR tank, the NOx concentration of the outlet position of the first SCR tank is close to the second NOx concentration, and if the difference value of the NOx concentration and the second NOx concentration is smaller than a preset threshold value.
Alternatively, as shown in fig. 4, a further reductant injection control method provided in an embodiment of the present invention may further include, based on the method shown in fig. 1:
s300, obtaining the working state of a first NOx sensor corresponding to the first NOx concentration and the working state of a second NOx sensor corresponding to the second NOx concentration; if the operating state of the first NOX sensor is a normal state and the operating state of the second NOX sensor is a normal state, step S100 is executed.
The operating states of the first and second NOx sensors need to be obtained because: the abnormality of the first NOX concentration or the second NOX concentration may be caused by an operation abnormality of the respective corresponding NOX sensor, so that it is necessary to eliminate the problem of an emission abnormality caused by the operation abnormality of the sensor before adjusting the injection amount, and the adjustment accuracy is improved.
Whether the operating states of the first NOX sensor and the second NOX sensor are normal states or abnormal states depends on the contents of the messages sent by the first NOX sensor and the second NOX sensor, and specific embodiments thereof are not described.
If the working state of one of the first NOx sensor and the second NOx sensor is an abnormal state, the NOx sensor can cause the problem of NOx concentration, the reliability of the NOx concentration obtained by the NOx sensor is low, and the adjustment of the injection amount is forbidden; if the operating states of the two NOX sensors are normal, indicating that the reliability is high, the injection amount may be adjusted based on the first NOX concentration and the second NOX concentration.
Alternatively, the embodiment of the invention may output the notification information of the NOX sensor malfunction when the operating state of the first NOX sensor is an abnormal state and/or the operating state of the second NOX sensor is an abnormal state.
It can be understood that the reducing agent injection control method provided by the embodiment of the invention is a dynamic process, and the injection quantity can be repeatedly adjusted based on the change of the NOX concentration under the current working condition and the change of the working condition, so that the working state of the NOX sensor can be periodically or irregularly determined in order to eliminate the NOX sensor causing the NOX concentration abnormality.
In accordance with an embodiment of the method described above, an embodiment of the present invention provides a reducing agent injection control device, which is configured as shown in fig. 5, and includes:
an obtaining module 100 for obtaining a first NOx concentration at an outlet position of a first SCR tank and a second NOx concentration at an outlet position of a second SCR tank;
the first SCR box and the second SCR box are positioned in the same engine, and exhaust gas emitted by the engine is divided into the first SCR box and the second SCR box so as to perform chemical action on the exhaust gas in the two SCR boxes to reduce the concentration of NOx in the exhaust gas.
The obtaining module 100 in the embodiment of the present invention may obtain a first NOX concentration and a second NOX concentration at outlet positions of the first SCR tank and the second SCR tank by NOX sensors at the outlet positions, and the two NOX concentrations are used for judging whether a certain SCR tank with deteriorated NOX emission exists in the two SCR tanks. Whether NOx emissions of the first SCR tank or the second SCR tank are in degradation is determined, for example, by the first NOx concentration and the second NOx concentration.
An adjustment module 200 that adjusts an injection amount of a reducing agent into the first SCR tank at least twice based on the first NOx concentration, the second NOx concentration, and a first injection amount of the reducing agent when the first SCR tank emits the first NOx concentration if NOx emission of the first SCR tank is determined to be degrading based on the first NOx concentration and the second NOx concentration.
It can be understood that: under the current working condition of the engine, the amount of exhaust gas evenly distributed to the first SCR tank and the second SCR tank is the same, and the injection amounts of reducing agents of the two SCR tanks are close to each other, so that the first NOx concentration and the second NOx concentration are consistent or close to each other (if the absolute value of the difference value of the two NOx concentrations is smaller than a preset threshold value). When the first NOx concentration is inconsistent with the second NOx concentration or the difference is large (for example, the absolute value of the difference between the two NOx concentrations is larger than the maximum absolute value of the difference between the two NOx concentrations in the current working condition), the SCR tank with degraded NOx emission exists in the first SCR tank and the second SCR tank. As to how much the first NOx concentration does not coincide with the second NOx concentration, an SCR tank is determined that has NOx emissions that are in degradation.
The points to be explained are: the reason that the first NOX concentration is inconsistent with the second NOX concentration or has a large difference is that the SCR box is unstable and the time when the situation occurs is less than the preset time, and no adjustment is needed at this time.
The preset threshold, the preset time and the preset duration may be determined according to actual requirements, which is not limited in this embodiment.
According to the technical scheme, the reducing agent injection control device provided by the embodiment of the invention can obtain the first NOx concentration of the outlet position of the first SCR tank and the second NOx concentration of the outlet position of the second SCR tank; if the NOx emission of the first SCR box is determined to be in degradation based on the first NOx concentration and the second NOx concentration, the injection amount of the reducing agent to the first SCR box is adjusted at least twice based on the first NOx concentration, the second NOx concentration and the first injection amount of the reducing agent when the first SCR box emits the first NOx concentration, when one of the two SCR boxes is in degradation due to blockage of the nozzle, the degraded SCR box can be accurately positioned through the NOx concentrations of the two SCR boxes, the NOx emission is improved by adjusting the injection amount of the reducing agent of the degraded SCR box, therefore, the problem of degradation in emission can be effectively solved through an injection amount adjusting mode when the nozzle is blocked, and further, the NOx concentration in the exhaust gas can be effectively reduced.
Optionally, as shown in fig. 6, the adjusting module 200 includes:
a first obtaining unit 210 configured to obtain an absolute value of a difference between the first NOX concentration and the second NOX concentration;
after obtaining the first NOX concentration and the second NOX concentration, the absolute value of the difference between the first NOX concentration and the second NOX concentration is calculated, and the absolute value of the difference is adopted because the NOX concentration of each SCR tank is not recorded in the operating condition table for recording the standard parameters of the current operating condition of the engine, but the absolute value of the difference between the NOX concentrations of the two SCR tanks is recorded, and therefore the absolute value of the difference is calculated instead of the difference. Since the first NOx concentration should be consistent with or close to the second NOx concentration under the same operating condition, the difference in catalytic reduction between the first SCR tank and the second SCR tank may be reflected by the absolute value of the difference between the first NOx concentration and the second NOx concentration.
A first adjusting unit 220, configured to adjust an injection amount of a reducing agent of the first SCR tank based on the first NOX concentration, the second NOX concentration and the first injection amount if the absolute difference value is greater than a maximum absolute difference value corresponding to a current operating condition of an engine to which the first SCR tank belongs and the first NOX concentration is greater than the second NOX concentration, and it is determined that NOX emission of the first SCR tank is in degradation;
under the current working condition of the engine, if the absolute value of the difference value between the first NOx concentration and the second NOx concentration is larger than the maximum absolute value of the difference value corresponding to the current working condition, the SCR tank with degraded NOx emission exists in the first SCR tank and the second SCR tank.
According to the embodiment of the invention, after the absolute value of the difference between the first NOx concentration and the second NOx concentration under the current working condition is larger than the maximum absolute value of the difference corresponding to the current working condition, the SCR box with the higher NOx concentration in the first SCR box and the second SCR box is determined as the SCR box with the degraded NOx emission. For example, if the absolute value of the difference between the first NOx concentration and the second NOx concentration of the current operating condition is 7 and is greater than the maximum absolute value of the difference 5 corresponding to the current operating condition, where the first NOx concentration is 75mol/L (moles/liter) and the second NOx concentration is 50mol/L (moles/liter), the NOx emission of the first SCR tank is determined to be in degradation.
In this embodiment, if it is determined that the NOX emission of the first SCR tank is in degradation, the injection amount of the reducing agent of the first SCR tank may be adjusted based on the first NOX concentration, the second NOX concentration, and the first injection amount, and the specific process may be: deriving a compensation factor based on the first NOx concentration and the second NOx concentration; adjusting an injection amount of reductant of the first SCR tank at a time based on the first injection amount and the compensation factor.
Specifically, the compensation factor may be a ratio of the first NOX concentration to the second NOX concentration, and assuming that the first NOX concentration is Ra, the second NOX concentration is Rb, and Ra is greater than Rb, the compensation factor N is Ra/Rb. For example, the first NOx concentration is 75mol/L (moles/liter) and the second NOx concentration is 50mol/L (moles/liter), which are compared to each other to obtain a compensation factor of 1.5.
And the manner of adjusting the injection amount based on the first injection amount and the compensation factor may be, but is not limited to: the injection quantity of the reducing agent in the first SCR tank is adjusted based on the product of the first injection quantity and the compensation factor, specifically, the product of the first injection quantity and the compensation factor is used as the adjusted injection quantity, and when the ratio of the first NOx concentration to the second NOx concentration is used as the compensation factor, the value of the compensation factor is larger than 1, so that the adjustment of the first SCR tank can increase the injection quantity of the reducing agent in the first SCR tank. For example, if the first injection amount of the reducing agent when the first SCR tank emits the first NOX concentration is 30mol/L (mol/L) and the value obtained by multiplying the first injection amount by the compensation factor 1.5 is 45mol/L (mol/L), the injection amount of the reducing agent in the first SCR tank is adjusted to 45mol/L (mol/L).
A second obtaining unit 230 for obtaining a third NOX concentration at an outlet position of the first SCR tank under the influence of the adjusted injection amount of the reducing agent;
specifically, after the injection amount of the reducing agent of the first SCR tank is adjusted according to a value obtained by multiplying the first injection amount of the reducing agent by the compensation factor when the first SCR tank emits the first NOX concentration, the adjusted third NOX concentration at the outlet position of the first SCR tank is obtained. In general, the NOX concentration at the outlet position of the first SCR tank changes after the injection amount of the reducing agent in the first SCR tank is adjusted. For example: when the first injection amount of the reducing agent of the first SCR tank is 10mol/L, the first NOX concentration emitted may be 80mol/L, and after the injection amount of the reducing agent of the first SCR tank is adjusted to 30mol/L, the third NOX concentration emitted by the first SCR tank may be 50 mol/L.
A second adjusting unit 240 for adjusting the injection amount of the reducing agent of the first SCR tank to the first injection amount if it is determined that the NOx emission of the first SCR tank is still in degradation based on the third NOx concentration and the first NOx concentration;
that is, the NOX emission of the first SCR tank is still in degradation, which is determined relative to the NOX emission of the first SCR tank before the adjustment (i.e., the first NOX concentration) and the NOX emission of the first SCR tank after the adjustment (i.e., the third NOX concentration), so that the adjustment does not improve the emission.
In an embodiment of the present invention, the second adjusting unit 240 may determine whether the NOX emission of the first SCR tank is further deteriorated by: determining that NOx emissions of the first SCR tank are still in degradation if the third NOx concentration is greater than or equal to the first NOx concentration.
It can be appreciated that an object of an embodiment of the present invention is to adjust the injection amount of the reducing agent in the first SCR tank such that the adjusted third NOX concentration in the first SCR tank is less than the first NOX concentration, and when the third NOX concentration is greater than the first NOX concentration, it can be determined that the NOX emission of the first SCR tank is further deteriorated after the adjustment of the injection amount of the reducing agent in the first SCR tank, and therefore it is necessary to adjust the injection amount of the reducing agent in the first SCR tank back to the first injection amount.
A third adjusting unit 250 for adjusting an injection amount of a reducing agent of the first SCR tank based on the third NOx concentration, the second NOx concentration and the first injection amount if it is determined that NOx emission of the first SCR tank is improving based on the third NOx concentration and the first NOx concentration.
The same way of improving or not is similar to the above-described way of determining whether or not there is further deterioration: whether the third NOX concentration is greater than or equal to the first NOX concentration is judged, and if the third NOX concentration is less than the first NOX concentration, it is determined that the NOX emission of the first SCR tank is under improvement, at which time the third adjustment unit 250 may continue to adjust the injection amount of the reducing agent of the first SCR tank according to the third NOX concentration, the second NOX concentration, and the first injection amount.
Optionally, the third adjusting unit 250 includes: the system comprises a first determining subunit, a first obtaining subunit, a first adjusting subunit, a second obtaining subunit, a third adjusting subunit and a third obtaining subunit.
A first determining subunit, configured to determine that NOX emission of the first SCR tank is under improvement if an absolute value of a difference between the third NOX concentration and the second NOX concentration is greater than a maximum absolute value of a difference corresponding to a current operating condition of an engine to which the first SCR tank belongs, but the third NOX concentration is less than the first NOX concentration;
specifically, when the absolute value of the difference between the third NOX concentration and the second NOX concentration is greater than the maximum absolute value of the difference corresponding to the current operating condition of the engine in which the first SCR tank is located, it indicates that the NOX emission of the first SCR tank after the injection amount of the reducing agent is adjusted is still in degradation, but the third NOX concentration is smaller than the first NOX concentration, that is, the absolute value of the difference between the third NOX concentration and the second NOX concentration is smaller than the absolute value of the difference between the first NOX concentration and the second NOX concentration, so it can be indicated that the NOX emission of the first SCR tank is in improvement before the injection amount of the reducing agent is not adjusted.
For example, the second NOX concentration is 50mol/L and the maximum absolute value of the difference corresponding to the current operating condition of the engine in which the first SCR tank is located is 3, the first NOX concentration obtained before the injection amount of the reducing agent in the first SCR tank is adjusted is 90mol/L, and after the injection amount of the reducing agent in the first SCR tank is adjusted, the third NOX concentration obtained in the first SCR tank is 60mol/L although the absolute value of the difference between the third NOX concentration 60mol/L and the second NOX concentration 50mol/L is greater than 5 and the third NOX concentration 60mol/L is smaller than the first NOX concentration 90mol/L, which means that after the injection amount of the reducing agent in the first SCR tank is adjusted, the NOX emission of the first SCR tank is in improvement compared to before the adjustment, however, since the first SCR tank is still in a deteriorated state with respect to the second SCR tank, it is necessary to continuously adjust the injection amount of the reducing agent in the first SCR tank in addition to the injection amount of the reducing agent when the first SCR tank discharges the third NOX concentration.
A first obtaining subunit configured to obtain a current compensation factor based on the third NOX concentration and the second NOX concentration;
specifically, the current compensation factor may be a ratio of the third NOx concentration and the second NOx concentration. The process of obtaining the current compensation factor based on the third NOX concentration and the second NOX concentration is the same as the method of obtaining the compensation factor based on the first NOX concentration and the second NOX concentration, and the detailed description is referred to the above, and will not be repeated herein.
A first adjusting subunit for deriving a second injection quantity based on the first injection quantity, a current compensation factor, and a previous compensation factor, the previous compensation factor being derived based on a previous NOx concentration of the first SCR tank and the second NOx concentration;
for ease of understanding, the following is exemplified here: if the first injection amount of the reducing agent is 60mol/L (mol/L) when the second NOx concentration is 50mol/L (mol/L), the first SCR tank discharges 90mol/L (mol/L) of the first NOx concentration, the compensation factor obtained based on the first NOx concentration and the second NOx concentration is 1.5, the injection amount of the reducing agent of the first SCR tank is 90mol/L (mol/L) after the first injection amount of the reducing agent of the first SCR tank is adjusted to 60mol/L (mol/L), if the third NOx concentration obtained when the injection amount of the reducing agent of the first SCR tank is 90mol/L (mol/L) is 60mol/L (mol/L), the current compensation factor obtained based on the third NOx concentration and the second NOx concentration is 1.2, the second injection amount is 60mol/L (mol/L) multiplied by the compensation factor 1.5, and then multiplied by the current 162mol value of the compensation factor 1.2 L (mol/L).
A second adjustment subunit configured to adjust an injection amount of the reducing agent of the first SCR tank to the second injection amount;
a second obtaining subunit configured to obtain a fourth NOX concentration at an outlet position of the first SCR tank by a second injection amount of the reducing agent;
a third adjusting subunit, configured to maintain the injection amount of the reducing agent in the first SCR tank as the second injection amount if an absolute value of a difference between the fourth NOX concentration and the second NOX concentration is less than or equal to a maximum absolute value of a difference corresponding to a current operating condition of an engine to which the first SCR tank belongs;
specifically, when the absolute value of the difference between the fourth NOX concentration and the second NOX concentration at the outlet of the first SCR tank is smaller than or equal to the maximum absolute value of the difference corresponding to the current operating condition of the engine to which the first SCR tank belongs, it is indicated that the NOX emission of the first SCR tank is substantially consistent with the NOX emission of the second SCR tank, and the NOX emission of the first SCR tank returns to normal, so that the second injection amount of the reducing agent when the first SCR tank emits the fourth NOX concentration is maintained without changing the current operating condition after the NOX emission of the first SCR tank returns to normal.
And a third obtaining subunit, configured to trigger the first obtaining subunit to repeatedly adjust an injection amount of the reducing agent in the first SCR tank until NOX emission of the first SCR tank returns to normal, taking the fourth NOX concentration as the third NOX concentration, if an absolute value of a difference between the fourth NOX concentration and the second NOX concentration is greater than the maximum absolute value of the difference, but the fourth NOX concentration is smaller than the third NOX concentration.
It can be understood that if the absolute value of the difference between the fourth NOX concentration and the second NOX concentration is still greater than the maximum absolute value of the difference, but the fourth NOX concentration is less than the third NOX concentration, it means that the NOX emission of the first SCR tank continues to be improved, and therefore, it is necessary to continue to make a further adjustment of the injection quantity of the reducing agent into the first SCR tank on the basis of the fourth NOX concentration, which may be the triggering of the first obtaining subunit with the fourth NOX concentration as the third NOX concentration.
Alternatively, as shown in fig. 7, a reductant injection control device according to another embodiment of the present invention may further include:
the state obtaining module 300 is configured to obtain an operating state of a first NOX sensor corresponding to the first NOX concentration and an operating state of a second NOX sensor corresponding to the second NOX concentration, and trigger the obtaining module 100 if the operating state of the first NOX sensor is a normal state and the operating state of the second NOX sensor is a normal state.
The operating states of the first and second NOx sensors need to be obtained because: the abnormality of the first NOX concentration or the second NOX concentration may be caused by an operation abnormality of the respective corresponding NOX sensor, so that it is necessary to eliminate the problem of an emission abnormality caused by the operation abnormality of the sensor before adjusting the injection amount, and the adjustment accuracy is improved.
Whether the operating states of the first NOX sensor and the second NOX sensor are normal states or abnormal states depends on the contents of the messages sent by the first NOX sensor and the second NOX sensor, and specific embodiments thereof are not described.
If the working state of one of the first NOx sensor and the second NOx sensor is an abnormal state, the NOx sensor can cause the problem of NOx concentration, the reliability of the NOx concentration obtained by the NOx sensor is low, and the adjustment of the injection amount is forbidden; if the operating states of the two NOX sensors are normal, indicating that the reliability is high, the injection amount may be adjusted based on the first NOX concentration and the second NOX concentration.
Alternatively, the embodiment of the invention may output the notification information of the NOX sensor malfunction when the operating state of the first NOX sensor is an abnormal state and/or the operating state of the second NOX sensor is an abnormal state.
It is understood that the reducing agent injection control device provided by the embodiment of the invention executes a dynamic process, and repeatedly adjusts the injection quantity based on the change of the NOX concentration under the current working condition and the change of the working condition, so that the working state of the NOX sensor can be determined periodically or irregularly in order to eliminate the NOX concentration abnormality caused by the NOX sensor.
According to the storage medium provided by the embodiment of the invention, the storage medium stores computer-executable instructions, and when the computer-executable instructions are loaded and executed by a processor, the reducing agent injection control method is realized.
It should be noted that, in the present specification, the embodiments are all described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments may be referred to each other. For the device-like embodiment, since it is basically similar to the method embodiment, the description is simple, and for the relevant points, reference may be made to the partial description of the method embodiment.
Finally, it should also be 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. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention 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.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims (10)

1. A reducing agent injection control method, characterized by comprising:
obtaining a first NOx concentration at an exit location of a first SCR tank and a second NOx concentration at an exit location of a second SCR tank, wherein exhaust gas emitted by an engine is divided equally into the first SCR tank and the second SCR tank;
if NOx emissions of the first SCR tank are determined to be in degradation based on the first NOx concentration and the second NOx concentration, adjusting an amount of injection of reductant into the first SCR tank at least twice based on the first NOx concentration, the second NOx concentration, and a first amount of injection of reductant when the first SCR tank emits the first NOx concentration.
2. The method of claim 1, wherein said adjusting the amount of injection of reductant of the first SCR tank at least twice based on the first NOx concentration, the second NOx concentration, and a first amount of injection of reductant at which the first SCR tank emits the first NOx concentration if NOx emission of the first SCR tank is determined to be degrading based on the first NOx concentration and the second NOx concentration comprises:
obtaining an absolute value of a difference between the first NOx concentration and the second NOx concentration;
if the absolute difference value is larger than the maximum absolute difference value corresponding to the current working condition of the engine to which the first SCR tank belongs and the first NOx concentration is larger than the second NOx concentration, determining that the NOx emission of the first SCR tank is in degradation, and adjusting the injection quantity of the reducing agent of the first SCR tank based on the first NOx concentration, the second NOx concentration and the first injection quantity;
obtaining a third NOx concentration at an outlet position of the first SCR tank under the action of the reducing agent of the adjusted injection amount;
adjusting an injection amount of reductant of the first SCR tank to the first injection amount if it is determined that NOx emissions of the first SCR tank are still in degradation based on the third NOx concentration and the first NOx concentration;
adjusting an injection amount of reductant of the first SCR tank based on the third NOx concentration, second NOx concentration, and the first injection amount if NOx emission of the first SCR tank is determined to be improving based on the third NOx concentration and the first NOx concentration.
3. The method of claim 2, wherein said adjusting an injection amount of reductant of the first SCR tank based on the first NOX concentration, the second NOX concentration, and the first injection amount comprises:
deriving a compensation factor based on the first NOx concentration and the second NOx concentration;
adjusting an injection amount of reductant of the first SCR tank at a time based on the first injection amount and the compensation factor.
4. The method of claim 2, wherein said adjusting the injection amount of reductant of the first SCR tank to the first injection amount if it is determined that NOx emissions of the first SCR tank are still in degradation based on the third NOx concentration and the first NOx concentration comprises:
determining that NOx emissions of the first SCR tank are still in degradation if the third NOx concentration is greater than or equal to the first NOx concentration;
adjusting an injection amount of the reducing agent of the first SCR tank to the first injection amount.
5. The method of claim 2, wherein said adjusting an injection amount of reductant of the first SCR tank based on the third NOx concentration, second NOx concentration, and the first injection amount if NOx emissions of the first SCR tank are determined to be under improvement based on the third NOx concentration and the first NOx concentration comprises:
determining that the NOx emission of the first SCR tank is in improvement if the absolute value of the difference between the third NOx concentration and the second NOx concentration is greater than the maximum absolute value of the difference corresponding to the current working condition of the engine to which the first SCR tank belongs, but the third NOx concentration is less than the first NOx concentration;
deriving a current compensation factor based on the third NOx concentration and the second NOx concentration;
deriving a second injection quantity based on the first injection quantity, a current compensation factor, and a previous compensation factor, the previous compensation factor derived based on a previous NOx concentration of the first SCR tank and the second NOx concentration;
adjusting an injection amount of the reducing agent of the first SCR tank to the second injection amount;
obtaining a fourth NOX concentration at an outlet position of the first SCR tank under the influence of the second injected amount of reductant;
if the absolute value of the difference between the fourth NOx concentration and the second NOx concentration is smaller than or equal to the maximum absolute value of the difference corresponding to the current working condition of the engine to which the first SCR tank belongs, maintaining the injection quantity of the reducing agent of the first SCR tank as the second injection quantity;
and if the absolute value of the difference between the fourth NOx concentration and the second NOx concentration is larger than the maximum absolute value of the difference, but the fourth NOx concentration is smaller than the third NOx concentration, taking the fourth NOx concentration as the third NOx concentration, and returning to the step of obtaining the current compensation factor based on the third NOx concentration and the second NOx concentration.
6. The method of claim 1, further comprising:
obtaining an operating state of a first NOx sensor corresponding to the first NOx concentration and an operating state of a second NOx sensor corresponding to the second NOx concentration;
the step of obtaining a first NOx concentration at an exit location of a first Selective Catalytic Reduction (SCR) tank and a second NOx concentration at an exit location of a second SCR tank is performed if an operating state of the first NOx sensor is a normal state and an operating state of the second NOx sensor is a normal state.
7. A reducing agent injection control device, characterized by comprising:
an obtaining module to obtain a first NOx concentration at an exit position of a first SCR tank and a second NOx concentration at an exit position of a second SCR tank, wherein exhaust gas emitted by an engine is divided equally into the first SCR tank and the second SCR tank;
an adjustment module to adjust an injection amount of reductant to the first SCR tank at least twice based on the first NOx concentration, the second NOx concentration, and a first injection amount of reductant at which the first SCR tank emits the first NOx concentration if NOx emission of the first SCR tank is determined to be degrading based on the first NOx concentration and the second NOx concentration.
8. The apparatus of claim 7, wherein the adjustment module comprises:
a first obtaining unit configured to obtain an absolute value of a difference between the first NOX concentration and the second NOX concentration;
a first adjusting unit, configured to, if the absolute difference value is greater than a maximum absolute difference value corresponding to a current operating condition of an engine to which the first SCR tank belongs and the first NOX concentration is greater than the second NOX concentration, determine that NOX emission of the first SCR tank is in degradation, adjust an injection amount of a reducing agent of the first SCR tank based on the first NOX concentration, the second NOX concentration, and the first injection amount;
a second obtaining unit, which is also used for obtaining a third NOx concentration of the outlet position of the first SCR tank under the action of the reducing agent of the adjusted injection quantity;
a second adjusting unit for adjusting the injection amount of the reducing agent of the first SCR tank to the first injection amount if it is determined that the NOx emission of the first SCR tank is still in deterioration based on the third NOx concentration and the first NOx concentration;
a third adjusting unit further configured to adjust an injection amount of the reducing agent of the first SCR tank based on the third NOx concentration, the second NOx concentration, and the first injection amount if it is determined that NOx emission of the first SCR tank is improving based on the third NOx concentration and the first NOx concentration.
9. The apparatus of claim 8, wherein the third adjusting unit comprises:
a first determining subunit, configured to determine that NOX emission of the first SCR tank is under improvement if an absolute value of a difference between the third NOX concentration and the second NOX concentration is greater than a maximum absolute value of a difference corresponding to a current operating condition of an engine to which the first SCR tank belongs, but the third NOX concentration is less than the first NOX concentration;
a first obtaining subunit configured to obtain a current compensation factor based on the third NOX concentration and the second NOX concentration;
a first adjusting subunit for deriving a second injection quantity based on the first injection quantity, a current compensation factor, and a previous compensation factor, the previous compensation factor being derived based on a previous NOx concentration of the first SCR tank and the second NOx concentration;
a second adjustment subunit configured to adjust an injection amount of the reducing agent of the first SCR tank to the second injection amount;
a second obtaining subunit configured to obtain a fourth NOX concentration at an outlet position of the first SCR tank by a second injection amount of the reducing agent;
a third adjusting subunit, configured to maintain the injection amount of the reducing agent in the first SCR tank as the second injection amount if an absolute value of a difference between the fourth NOX concentration and the second NOX concentration is less than or equal to a maximum absolute value of a difference corresponding to a current operating condition of an engine to which the first SCR tank belongs;
a third obtaining sub-unit configured to trigger the first obtaining sub-unit with the fourth NOX concentration as the third NOX concentration if an absolute value of a difference between the fourth NOX concentration and the second NOX concentration is larger than the maximum absolute value of the difference, but the fourth NOX concentration is smaller than the third NOX concentration.
10. The apparatus of claim 7, further comprising:
and the state obtaining module is used for obtaining the working state of a first NOx sensor corresponding to the first NOx concentration and the working state of a second NOx sensor corresponding to the second NOx concentration, and if the working state of the first NOx sensor is a normal state and the working state of the second NOx sensor is a normal state, the obtaining module is triggered.
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