CN112627955A - SCR catalyst removal diagnosis method, device, equipment and storage medium - Google Patents

SCR catalyst removal diagnosis method, device, equipment and storage medium Download PDF

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Publication number
CN112627955A
CN112627955A CN202011456104.5A CN202011456104A CN112627955A CN 112627955 A CN112627955 A CN 112627955A CN 202011456104 A CN202011456104 A CN 202011456104A CN 112627955 A CN112627955 A CN 112627955A
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temperature
scr catalyst
upstream
downstream
scr
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张苏苏
张硕
于双飞
朱娟
张淑宁
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Weichai Power Co Ltd
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Weichai Power Co Ltd
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Priority to CN202111492690.3A priority patent/CN114135378B/en
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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
    • 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
    • F01N3/08—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
    • F01N3/2006—Periodically heating or cooling catalytic reactors, e.g. at cold starting or overheating
    • F01N3/2046—Periodically cooling catalytic reactors
    • 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
    • F01N2250/00—Combinations of different methods of purification
    • F01N2250/02—Combinations of different methods of purification filtering and catalytic conversion
    • 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
    • F01N2550/24—Determining the presence or absence of an exhaust treating device
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2900/00—Details of electrical control or of the monitoring of the exhaust gas treating apparatus
    • F01N2900/04—Methods of control or diagnosing
    • F01N2900/0416—Methods of control or diagnosing using the state of a sensor, e.g. of an exhaust gas sensor
    • 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)

Abstract

The embodiment of the invention provides a method, a device and equipment for diagnosing removal of an SCR (selective catalytic reduction) catalyst and a storage medium, wherein the method comprises the steps of determining the upstream temperature and the downstream temperature of the SCR catalyst when a vehicle enters a parking regeneration state; when the vehicle is determined to be in a regeneration stage and the upstream temperature and the downstream temperature are both higher than preset temperature thresholds, continuously detecting the upstream temperature and the downstream temperature of the SCR catalyst after the vehicle enters a cooling stage; and determining that the SCR catalyst is removed when the speed of the device heat emission between the upstream temperature corresponding position and the downstream temperature corresponding position exceeds a preset speed threshold according to the upstream temperature and the downstream temperature of the SCR catalyst. In the implementation process, only a temperature sensor with a simpler working principle is needed. Compared with the prior art, the method has lower cost, can judge under an unstable working condition, and can also avoid the problem of misjudgment caused by the influence of other factors on the SCR conversion efficiency.

Description

SCR catalyst removal diagnosis method, device, equipment and storage medium
Technical Field
The invention relates to the technical field of automobiles, in particular to a method, a device, equipment and a storage medium for diagnosing removal of an SCR (selective catalytic reduction) catalyst.
Background
Selective Catalytic Reduction (SCR) technology is an exhaust gas treatment technology applied to diesel vehicles and is used to treat nitrogen oxides in exhaust gas of the vehicles. If the SCR catalyst is removed, the exhaust pollutants emitted by the vehicle during operation may exceed the specified standards, causing significant pollution to the air.
In the prior art, it is mainly diagnosed whether the SCR catalyst is removed by the SCR conversion efficiency. A relatively stable operating condition is required for SCR conversion efficiency diagnostics. However, many off-road vehicles (such as off-road vehicles, construction machines, agricultural tractors, etc.) have unstable working conditions, and cannot use the prior art to diagnose whether the SCR catalyst is removed during working, so that the vehicle can still continue to work under the condition of excessive emission. In addition, because there are many factors that affect the SCR conversion efficiency, it is not possible to determine whether the factor is that the SCR catalyst is removed in some cases.
Disclosure of Invention
The embodiment of the invention provides a method, a device and equipment for diagnosing removal of an SCR (selective catalytic reduction) catalyst and a storage medium, which are used for solving the problem that whether the SCR catalyst is removed or not can not be diagnosed on non-road vehicles with unstable working conditions in the prior art.
The embodiment of the invention provides a method for removing and diagnosing an SCR (selective catalytic reduction) catalyst, which comprises the following steps of:
determining that the vehicle enters a parking regeneration state, and detecting the upstream temperature and the downstream temperature of the selective catalytic reduction SCR catalyst;
when the vehicle is determined to be in a regeneration stage and the upstream temperature and the downstream temperature are both higher than preset temperature thresholds, continuously detecting the upstream temperature and the downstream temperature of the SCR catalyst after the vehicle enters a cooling stage;
and determining that the SCR catalyst is removed when the speed of the device heat emission between the upstream temperature corresponding position and the downstream temperature corresponding position exceeds a preset speed threshold according to the upstream temperature and the downstream temperature of the SCR catalyst.
Optionally, when the first cooling time is less than a preset time threshold, determining that the speed of heat discharged by the equipment between the upstream temperature corresponding position and the downstream temperature corresponding position exceeds a preset speed threshold;
wherein the first cool-down time is a duration in which a temperature difference between an upstream temperature of the SCR catalyst and a downstream temperature of the SCR catalyst is greater than a preset temperature difference.
Optionally, when the total exhaust heat of the cooling stage is less than a preset exhaust heat, determining that a speed of the device exhaust heat between the upstream temperature corresponding location and the downstream temperature corresponding location exceeds a preset speed threshold.
Optionally, the total exhaust heat is:
Figure BDA0002828470920000021
wherein Q is the total heat of discharge, t0The duration of the cooling stage, t is any moment in the cooling stage, c is the specific heat capacity of the exhaust gas, qm(T) is the mass flow rate of exhaust gas emitted by the equipment between the upstream temperature corresponding position and the downstream temperature corresponding position at the time T, T2(T) the SCR upstream temperature at time T, T1(t) is the SCR downstream temperature at time t.
Optionally, when it is determined that both the upstream temperature and the downstream temperature are higher than the preset temperature threshold, the method further includes:
and if the time that the SCR downstream temperature is higher than the SCR upstream temperature exceeds the preset fault time, judging whether the SCR catalyst is removed or not.
Optionally, the SCR catalyst removal diagnostic method further includes:
if an upstream temperature sensor for detecting the temperature upstream of the SCR catalyst fails, the temperature upstream of the oxidation catalytic converter DOC or the temperature upstream of the particulate trap DPF is used as the temperature upstream of the SCR catalyst.
Optionally, the SCR catalyst removal diagnostic method further includes:
if a downstream temperature sensor for detecting a downstream temperature of the SCR catalyst fails, it is determined whether the SCR catalyst is removed.
Based on the same inventive concept, an embodiment of the present invention further provides an SCR catalyst removal diagnosis apparatus, including:
the starting module is used for determining that the vehicle enters a parking regeneration state and detecting the upstream temperature and the downstream temperature of the selective catalytic reduction SCR catalyst;
the detection module is used for continuously detecting the upstream temperature and the downstream temperature of the SCR catalyst after the vehicle enters a cooling stage when the vehicle is determined to be in a regeneration stage and the upstream temperature and the downstream temperature are both higher than preset temperature thresholds;
and the judging module is used for determining that the SCR catalyst is removed when the speed of the device heat emission between the upstream temperature corresponding position and the downstream temperature corresponding position exceeds a preset speed threshold according to the upstream temperature and the downstream temperature of the SCR catalyst.
Optionally, when the first cooling time is less than a preset time threshold, determining that the speed of heat discharged by the equipment between the upstream temperature corresponding position and the downstream temperature corresponding position exceeds a preset speed threshold;
wherein the first cool-down time is a duration in which a temperature difference between an upstream temperature of the SCR catalyst and a downstream temperature of the SCR catalyst is greater than a preset temperature difference.
Optionally, when the total amount of exhaust heat of the cooling phase is less than a preset amount of exhaust heat, determining that the speed of the vehicle's exhaust heat exceeds a preset speed threshold.
Optionally, the total exhaust heat is:
Figure BDA0002828470920000031
wherein Q is the total heat of discharge, t0The duration of the cooling stage, t is any moment in the cooling stage, c is the specific heat capacity of the exhaust gas, qm(T) is the mass flow rate of exhaust gas emitted by the equipment between the upstream temperature corresponding position and the downstream temperature corresponding position at the time T, T2(T) the SCR upstream temperature at time T, T1(t) is the SCR downstream temperature at time t.
Optionally, when it is determined that both the upstream temperature and the downstream temperature are higher than a preset temperature threshold, the SCR catalyst removal diagnosis device further includes:
and the dynamic fault detection module is used for judging whether the SCR catalyst cannot be diagnosed to be removed or not if the time that the SCR downstream temperature is higher than the SCR upstream temperature exceeds the preset fault time.
Optionally, the SCR catalyst removal diagnostic device further includes:
a malfunction state operating module for using an upstream temperature of an oxidation catalytic converter DOC or an upstream temperature of a particulate trap DPF as an upstream temperature of the SCR catalyst if an upstream temperature sensor for detecting the upstream temperature of the SCR catalyst malfunctions.
Optionally, the SCR catalyst removal diagnostic device further includes:
a downstream fault module to determine if the SCR catalyst is removed if a downstream temperature sensor detecting a downstream temperature of the SCR catalyst is faulty.
Based on the same inventive concept, an embodiment of the present invention further provides an SCR catalyst removal diagnostic apparatus, including: a processor and a memory for storing processor-executable instructions;
wherein the processor is configured to execute the instructions to implement the SCR catalyst removal diagnostic method.
Based on the same inventive concept, the embodiment of the invention also provides a storage medium, wherein the storage medium stores a computer program, and the computer program is used for realizing the SCR catalyst removal diagnosis method.
The invention has the following beneficial effects:
according to the method, the device, the equipment and the storage medium for diagnosing the removal of the SCR catalyst, provided by the embodiment of the invention, whether the speed of the heat discharged by the equipment between the position corresponding to the upstream temperature and the position corresponding to the downstream temperature exceeds a preset speed threshold value is judged according to the upstream temperature and the downstream temperature of the SCR catalyst, so that whether the SCR catalyst is removed is further determined. In the implementation process, only a temperature sensor with a simpler working principle is needed. Compared with the prior art, the method has lower cost, can judge under an unstable working condition, and can also avoid the problem of misjudgment caused by the influence of other factors on the SCR conversion efficiency.
Drawings
FIG. 1 is a flow chart of a method of diagnosing SCR catalyst removal provided by an embodiment of the present invention;
FIG. 2 is a schematic structural diagram of an SCR catalyst removal diagnostic device provided in an embodiment of the present invention;
fig. 3 is a schematic structural diagram of an SCR catalyst removal diagnostic apparatus according to an embodiment of the present invention.
Detailed Description
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, the present invention is further described with reference to the accompanying drawings and examples. Example embodiments may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of example embodiments to those skilled in the art. The same reference numerals in the drawings denote the same or similar structures, and thus their repetitive description will be omitted. The words expressing the position and direction described in the present invention are illustrated in the accompanying drawings, but may be changed as required and still be within the scope of the present invention. The drawings of the present invention are for illustrative purposes only and do not represent true scale.
It should be noted that in the following description, specific details are set forth in order to provide a thorough understanding of the present invention. The invention can be implemented in a number of ways different from those described herein and similar generalizations can be made by those skilled in the art without departing from the spirit of the invention. Therefore, the present invention is not limited to the specific embodiments disclosed below. The description which follows is a preferred embodiment of the present application, but is made for the purpose of illustrating the general principles of the application and not for the purpose of limiting the scope of the application. The protection scope of the present application shall be subject to the definitions of the appended claims.
Interpretation of related terms:
firstly, a parking regeneration process:
the vehicle is heated to over 600 ℃ to remove the carbon deposit. The park regeneration process includes a regeneration phase and a cooling phase. Wherein the regeneration phase is a phase in which the vehicle maintains the exhaust gas temperature at more than 600 degrees. The cooling phase is a phase in which the vehicle lowers the exhaust temperature.
Second, Particulate trap (DPF):
a DPF is a ceramic filter installed in the exhaust system of a diesel engine. The DPF is used to trap particulate emissions. The working principle of the filter is that engine tail gas enters the DPF through a pipeline and passes through the bag type filter densely arranged in the DPF to adsorb carbon smoke particles on the filter made of metal fiber felt. When the adsorption amount of the particles reaches a certain degree, the burner at the tail end automatically ignites and burns the carbon smoke particles adsorbed on the burner into carbon dioxide (CO)2) And then is discharged.
Third, Oxidation catalytic converter (DOC):
the DOC is a tail gas installation treatment device installed in an engine exhaust pipeline. DOC converts carbon monoxide (CO) and hydrocarbons in engine exhaust to harmless water (H) through oxidation reactions2O) and carbon dioxide (CO)2) The apparatus of (1).
Fourthly, Selective Catalytic Reduction (SCR) technology:
the SCR technology is aimed at diesel motor vehicleNO in exhaust emissionxA processing method of (1). The working principle of the device is that engine tail gas enters an exhaust mixing pipe after coming out of a turbine, and a urea metering injection device arranged on the exhaust mixing pipe is used for injecting reducing agent ammonia or urea. The urea generates NH after hydrolysis and pyrolysis reaction at high temperature3：
(NH2)2CO+H2O→2NH3+CO2
Under the action of catalyst, NO in tail gas is converted into oxygenxReduction to N2And H2O：
NO+NO2+2NH3→2N2+3H2O
Excess NH3Is also oxidized to N2And leakage is prevented:
4NH3+3O2→2N2+6H2O
the following describes a selective catalytic reduction SCR catalyst removal diagnostic method, device, apparatus, and storage medium according to embodiments of the present invention with reference to the accompanying drawings.
The embodiment of the invention provides a method for removing and diagnosing an SCR (selective catalytic reduction) catalyst, which comprises the following steps of:
determining that the vehicle enters a parking regeneration state, and detecting the upstream temperature and the downstream temperature of the selective catalytic reduction SCR catalyst;
when the vehicle is determined to be in a regeneration stage and the upstream temperature and the downstream temperature are both higher than preset temperature thresholds, continuously detecting the upstream temperature and the downstream temperature of the SCR catalyst after the vehicle enters a cooling stage;
and determining that the SCR catalyst is removed when the speed of the device heat emission between the upstream temperature corresponding position and the downstream temperature corresponding position exceeds a preset speed threshold according to the upstream temperature and the downstream temperature of the SCR catalyst.
As shown in fig. 1, the method may specifically be:
s101, judging whether the vehicle is in a parking regeneration state or not;
s102, determining that the vehicle enters a parking regeneration state, and detecting the upstream temperature and the downstream temperature of an SCR catalyst;
s103, judging whether the vehicle is in a regeneration stage or not, and whether the upstream temperature and the downstream temperature are both higher than a preset temperature threshold or not;
s104, when the vehicle is determined to be in a regeneration stage and the upstream temperature and the downstream temperature are both higher than a preset temperature threshold value, waiting for the vehicle to enter a cooling stage;
s105, after the vehicle is determined to enter a cooling stage, continuously detecting the upstream temperature and the downstream temperature of the SCR catalyst;
s108, judging whether the speed of the heat discharged by the equipment between the position corresponding to the upstream temperature and the position corresponding to the downstream temperature exceeds a preset speed threshold value or not according to the upstream temperature and the downstream temperature of the SCR catalyst;
s109, if yes, determining that the SCR catalyst is removed;
s110, if not, determining that the SCR catalyst is not removed.
The upstream temperature of the SCR catalyst refers to the temperature of the tail gas before entering the SCR catalyst, and is acquired by an upstream temperature sensor arranged in the exhaust pipe at a position before an air inlet of the SCR catalyst. The downstream temperature of the SCR catalyst refers to the temperature of the exhaust gas after the exhaust gas is discharged from the SCR catalyst, and is acquired by a downstream temperature sensor arranged at a position behind the gas outlet of the SCR catalyst in an exhaust pipe.
In particular implementations, the vehicle may emit heat by emitting exhaust during the regeneration phase. If the SCR catalyst is not removed, the SCR catalyst absorbs a portion of the heat when treating the exhaust gas. This heat is discharged during the cooling phase as the vehicle cools. The vehicle should emit correspondingly more heat during the cooling process than when the SCR catalyst is removed. Meanwhile, due to the fact that the specific heat capacity of the SCR catalyst carrier is large, the temperature reduction speed corresponding to the discharged tail gas is low in the cooling stage compared with the temperature reduction speed when the SCR catalyst is removed. Therefore, it can be determined that the SCR catalyst is removed when the heat discharge speed of the device between the upstream temperature-corresponding position and the downstream temperature-corresponding position is fast during cooling.
In this way, according to the upstream temperature and the downstream temperature of the SCR catalyst, whether the speed of the device heat emission between the position corresponding to the upstream temperature and the position corresponding to the downstream temperature exceeds a preset speed threshold value or not is judged, and whether the SCR catalyst is removed or not is further determined. In the implementation process, only a temperature sensor with a simpler working principle is needed. Compared with the prior art, the method has lower cost, can judge under an unstable working condition, and can also avoid the problem of misjudgment caused by the influence of other factors on the SCR conversion efficiency.
Optionally, when the first cooling time is less than a preset time threshold, determining that the speed of heat discharged by the equipment between the upstream temperature corresponding position and the downstream temperature corresponding position exceeds a preset speed threshold;
wherein the first cool-down time is a duration in which a temperature difference between an upstream temperature of the SCR catalyst and a downstream temperature of the SCR catalyst is greater than a preset temperature difference.
Therefore, the speed is judged by the duration time required by discharging the same heat, the steps for realizing the method are less, and the corresponding software program for realizing the method has lower computation amount.
Optionally, when the total exhaust heat of the cooling stage is less than a preset exhaust heat, determining that a speed of the device exhaust heat between the upstream temperature corresponding location and the downstream temperature corresponding location exceeds a preset speed threshold.
In particular implementations, the vehicle may emit heat by emitting exhaust during the regeneration phase. If the SCR catalyst is not removed, the SCR catalyst absorbs a portion of the heat when treating the exhaust gas. This heat is discharged during the cooling phase as the vehicle cools. The vehicle should emit correspondingly more heat during the cooling process than when the SCR catalyst is removed. Therefore, it may be determined that the SCR catalyst is removed when the total amount of exhaust heat during the cooling phase is too small.
Therefore, the speed is judged according to the total heat discharged in the cooling stage, and the precision is high.
Optionally, the total exhaust heat is:
Figure BDA0002828470920000091
wherein Q is the total heat of discharge, t0The duration of the cooling stage, t is any moment in the cooling stage, c is the specific heat capacity of the exhaust gas, qm(T) is the mass flow rate of exhaust gas emitted by the equipment between the upstream temperature corresponding position and the downstream temperature corresponding position at the time T, T2(T) the SCR upstream temperature at time T, T1(t) is the SCR downstream temperature at time t.
Optionally, when it is determined that both the upstream temperature and the downstream temperature are higher than the preset temperature threshold, the method further includes:
s106, comparing whether the time that the SCR downstream temperature is higher than the SCR upstream temperature exceeds preset fault time or not;
s107, if the time that the SCR downstream temperature is higher than the SCR upstream temperature exceeds the preset fault time, judging whether the SCR catalyst is removed or not.
In theory, the SCR upstream temperature should be higher than the SCR downstream temperature. However, in the implementation process, due to the influence of error factors such as temperature drift and thermal inertia of the temperature sensor, a situation that the downstream temperature of the SCR is higher than the upstream temperature of the SCR may occur for a short time. If the SCR downstream temperature is higher than the SCR upstream temperature for too long, it may be that a malfunction of an upstream sensor detecting the SCR upstream temperature results in a lower measured SCR upstream temperature value and/or a malfunction of a downstream sensor detecting the SCR downstream temperature results in a higher measured SCR downstream temperature value.
Therefore, whether the sensor fails or not is determined by the fact that the time that the downstream temperature of the SCR is higher than the upstream temperature of the SCR exceeds the preset failure time, and misjudgment is avoided.
Optionally, the SCR catalyst removal diagnostic method further includes:
and S111, if an upstream temperature sensor for detecting the upstream temperature of the SCR catalyst fails, using the upstream temperature of the DOC or the upstream temperature of the DPF as the upstream temperature of the SCR catalyst.
In the specific implementation process, the installation positions of the tail gas treatment device are sequentially DPF, DOC and SCR catalysts. Thus, using the upstream temperature of the DPF or DOC instead of the SCR upstream temperature improves the adaptability of the method when the upstream temperature sensor fails.
Optionally, the SCR catalyst removal diagnostic method further comprises (not shown in fig. 1):
s112, if a downstream temperature sensor for detecting the downstream temperature of the SCR catalyst is in fault, judging whether the SCR catalyst is removed or not.
In this way, by stopping the determination of whether the SCR catalyst is removed when the downstream temperature sensor fails, the problem of erroneous determination is avoided.
Based on the same inventive concept, an embodiment of the present invention further provides an SCR catalyst removal diagnostic apparatus, as shown in fig. 2, including:
a start module M1 for determining that a vehicle is entering a park regeneration state, detecting an upstream temperature and a downstream temperature of a Selective Catalytic Reduction (SCR) catalyst;
the detection module M3 is configured to, when it is determined that the vehicle is in a regeneration phase and the upstream temperature and the downstream temperature are both higher than a preset temperature threshold, continuously detect the upstream temperature and the downstream temperature of the SCR catalyst after the vehicle enters a cooling phase;
and the judging module M4 is used for determining that the SCR catalyst is removed when the speed of the device heat emission between the upstream temperature corresponding position and the downstream temperature corresponding position exceeds a preset speed threshold according to the upstream temperature and the downstream temperature of the SCR catalyst.
Optionally, when the first cooling time is less than a preset time threshold, determining that the speed of heat discharged by the equipment between the upstream temperature corresponding position and the downstream temperature corresponding position exceeds a preset speed threshold;
wherein the first cool-down time is a duration in which a temperature difference between an upstream temperature of the SCR catalyst and a downstream temperature of the SCR catalyst is greater than a preset temperature difference.
Optionally, when the total exhaust heat of the cooling stage is less than a preset exhaust heat, determining that a speed of the device exhaust heat between the upstream temperature corresponding location and the downstream temperature corresponding location exceeds a preset speed threshold.
Optionally, the total exhaust heat is:
Figure BDA0002828470920000101
wherein Q is the total heat of discharge, t0The duration of the cooling stage, t is any moment in the cooling stage, c is the specific heat capacity of the exhaust gas, qm(T) is the mass flow rate of exhaust gas emitted by the equipment between the upstream temperature corresponding position and the downstream temperature corresponding position at the time T, T2(T) the SCR upstream temperature at time T, T1(t) is the SCR downstream temperature at time t.
Optionally, when it is determined that both the upstream temperature and the downstream temperature are higher than a preset temperature threshold, the SCR catalyst removal diagnosis device further includes:
a dynamic fault detection module M2 for determining that it is not possible to diagnose whether the SCR catalyst is removed if the time that the SCR downstream temperature is higher than the SCR upstream temperature exceeds a preset fault time.
Optionally, the SCR catalyst removal diagnostic device further includes:
a malfunction status operation module M5 for using the temperature upstream of the oxidation catalytic converter DOC or the temperature upstream of the particle trap DPF as the temperature upstream of the SCR catalyst if an upstream temperature sensor for detecting the temperature upstream of the SCR catalyst malfunctions.
Optionally, the SCR catalyst removal diagnostic device further includes:
a downstream fault module M6 for determining if the SCR catalyst is removed if a downstream temperature sensor for detecting a downstream temperature of the SCR catalyst is faulty.
In a specific implementation process, the principle of the SCR catalyst removal diagnosis device for solving the problem is similar to that of the SCR catalyst removal diagnosis method, so that the implementation of the device can refer to the implementation of the method, and repeated details are not repeated.
Based on the same inventive concept, an embodiment of the present invention further provides an SCR catalyst removal diagnostic apparatus, as shown in fig. 3, including: a processor 110 and a memory 120 for storing instructions executable by the processor 110; wherein the processor 110 is configured to execute the instructions to implement the SCR catalyst removal diagnostic method.
In particular implementations, the apparatus may vary widely depending on configuration or performance, and may include one or more processors 110 and memory 120, one or more storage media 130 storing applications 131 or data 132. Memory 120 and storage medium 130 may be, among other things, transient or persistent storage. The application 131 stored in the storage medium 130 may include one or more units (not shown in fig. 3) described above, and each module may include a series of instruction operations in the information processing apparatus. Further, the processor 110 may be configured to communicate with the storage medium 130 to execute a series of instruction operations in the storage medium 130 on the device. The apparatus may also include one or more power supplies (not shown in FIG. 3); one or more transceivers 140, the transceivers 140 comprising a wired or wireless network interface 141, one or more input-output interfaces 142; and/or one or more operating systems 133, such as Windows, Mac OS, Linux, IOS, Android, Unix, FreeBSD, etc.
Based on the same inventive concept, the embodiment of the invention also provides a storage medium, wherein the storage medium stores a computer program, and the computer program is used for realizing the SCR catalyst removal diagnosis method.
According to the method, the device, the equipment and the storage medium for diagnosing the removal of the SCR catalyst, provided by the embodiment of the invention, whether the speed of the heat discharged by the equipment between the position corresponding to the upstream temperature and the position corresponding to the downstream temperature exceeds a preset speed threshold value is judged according to the upstream temperature and the downstream temperature of the SCR catalyst, and whether the SCR catalyst is removed is further determined. In the implementation process, only a temperature sensor with a simpler working principle is needed. Compared with the prior art, the method has the advantages that the cost is low, the judgment can be carried out under an unstable working condition, and the problem of misjudgment caused by the fact that other factors influence the SCR conversion efficiency can be avoided.
As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to the application. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
It will be apparent to those skilled in the art that various changes and modifications may be made in the present application without departing from the spirit and scope of the application. Thus, if such modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is intended to include such modifications and variations as well.

Claims (16)

1. A selective catalytic reduction, SCR, catalyst removal diagnostic method comprising:
determining that the vehicle enters a parking regeneration state, and detecting the upstream temperature and the downstream temperature of the selective catalytic reduction SCR catalyst;
when the vehicle is determined to be in a regeneration stage and the upstream temperature and the downstream temperature are both higher than preset temperature thresholds, continuously detecting the upstream temperature and the downstream temperature of the SCR catalyst after the vehicle enters a cooling stage;
and determining that the SCR catalyst is removed when the speed of the device heat emission between the upstream temperature corresponding position and the downstream temperature corresponding position exceeds a preset speed threshold according to the upstream temperature and the downstream temperature of the SCR catalyst.
2. The SCR catalyst removal diagnostic method of claim 1, wherein the rate of plant exhaust heat between the upstream temperature-corresponding location and the downstream temperature-corresponding location is determined to exceed a preset rate threshold when the first cool-down time is less than a preset time threshold;
wherein the first cool-down time is a duration in which a temperature difference between an upstream temperature of the SCR catalyst and a downstream temperature of the SCR catalyst is greater than a preset temperature difference.
3. The SCR catalyst removal diagnostic method of claim 1, wherein the rate of plant exhaust heat between the upstream temperature-corresponding location and the downstream temperature-corresponding location is determined to exceed a preset rate threshold when the total exhaust heat of the cooling phase is less than a preset exhaust heat.
4. The SCR catalyst removal diagnostic method of claim 3, wherein the total exhaust heat is:
Figure FDA0002828470910000011
wherein Q is the total heat of discharge, t0The duration of the cooling stage, t is any moment in the cooling stage, c is the specific heat capacity of the exhaust gas, qm(T) is the mass flow rate of exhaust gas emitted by the equipment between the upstream temperature corresponding position and the downstream temperature corresponding position at the time T, T2(T) the SCR upstream temperature at time T, T1(t) is the SCR downstream temperature at time t.
5. The SCR catalyst removal diagnostic method of claim 1, wherein determining that the upstream temperature and the downstream temperature are both above a preset temperature threshold further comprises:
and if the time that the SCR downstream temperature is higher than the SCR upstream temperature exceeds the preset fault time, judging whether the SCR catalyst is removed or not.
6. The SCR catalyst removal diagnostic method of claim 1, further comprising:
if an upstream temperature sensor for detecting the temperature upstream of the SCR catalyst fails, the temperature upstream of the oxidation catalytic converter DOC or the temperature upstream of the particulate trap DPF is used as the temperature upstream of the SCR catalyst.
7. The SCR catalyst removal diagnostic method of claim 1, further comprising:
if a downstream temperature sensor for detecting a downstream temperature of the SCR catalyst fails, it is determined whether the SCR catalyst is removed.
8. An SCR catalyst removal diagnostic device, comprising:
the starting module is used for determining that the vehicle enters a parking regeneration state and detecting the upstream temperature and the downstream temperature of the selective catalytic reduction SCR catalyst;
the detection module is used for continuously detecting the upstream temperature and the downstream temperature of the SCR catalyst after the vehicle enters a cooling stage when the vehicle is determined to be in a regeneration stage and the upstream temperature and the downstream temperature are both higher than preset temperature thresholds;
and the judging module is used for determining that the SCR catalyst is removed when the speed of the device heat emission between the upstream temperature corresponding position and the downstream temperature corresponding position exceeds a preset speed threshold according to the upstream temperature and the downstream temperature of the SCR catalyst.
9. The SCR catalyst removal diagnostic apparatus of claim 8, wherein the rate of plant exhaust heat between the upstream temperature-corresponding location and the downstream temperature-corresponding location is determined to exceed a preset rate threshold when the first cool-down time is less than a preset time threshold;
wherein the first cool-down time is a duration in which a temperature difference between an upstream temperature of the SCR catalyst and a downstream temperature of the SCR catalyst is greater than a preset temperature difference.
10. The SCR catalyst removal diagnostic apparatus of claim 8, wherein the rate of plant exhaust heat between the upstream temperature-corresponding location and the downstream temperature-corresponding location is determined to exceed a preset rate threshold when the total exhaust heat of the cooling phase is less than a preset exhaust heat.
11. The SCR catalyst removal diagnostic device of claim 10, wherein the total exhaust heat is:
Figure FDA0002828470910000031
wherein Q is the total heat of discharge, t0The duration of the cooling stage, t is any moment in the cooling stage, c is the specific heat capacity of the exhaust gas, qm(T) is the mass flow rate of exhaust gas emitted by the equipment between the upstream temperature corresponding position and the downstream temperature corresponding position at the time T, T2(T) the SCR upstream temperature at time T, T1(t) is the SCR downstream temperature at time t.
12. The SCR catalyst removal diagnostic device of claim 8, wherein, when it is determined that both the upstream temperature and the downstream temperature are above a preset temperature threshold, the SCR catalyst removal diagnostic device further comprises:
and the dynamic fault detection module is used for judging whether the SCR catalyst cannot be diagnosed to be removed or not if the time that the SCR downstream temperature is higher than the SCR upstream temperature exceeds the preset fault time.
13. The SCR catalyst removal diagnostic device of claim 8, further comprising:
a malfunction state operating module for using an upstream temperature of an oxidation catalytic converter DOC or an upstream temperature of a particulate trap DPF as an upstream temperature of the SCR catalyst if an upstream temperature sensor for detecting the upstream temperature of the SCR catalyst malfunctions.
14. The SCR catalyst removal diagnostic device of claim 8, further comprising:
a downstream fault module to determine if the SCR catalyst is removed if a downstream temperature sensor detecting a downstream temperature of the SCR catalyst is faulty.
15. An SCR catalyst removal diagnostic apparatus, comprising: a processor and a memory for storing processor-executable instructions;
wherein the processor is configured to execute the instructions to implement the SCR catalyst removal diagnostic method of any one of claims 1-7.
16. A storage medium, characterized in that the storage medium stores a computer program for implementing the SCR catalyst removal diagnostic method according to any one of claims 1 to 7.
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