CN114233446A - Three-way catalyst efficiency diagnosis method, device and equipment - Google Patents

Three-way catalyst efficiency diagnosis method, device and equipment Download PDF

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Publication number
CN114233446A
CN114233446A CN202111554314.2A CN202111554314A CN114233446A CN 114233446 A CN114233446 A CN 114233446A CN 202111554314 A CN202111554314 A CN 202111554314A CN 114233446 A CN114233446 A CN 114233446A
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Prior art keywords
diagnosis
storage amount
oxygen storage
limit value
way catalyst
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CN114233446B (en
Inventor
李亮
孙丰山
王凯
唐志刚
王佳兴
曲志林
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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
    • 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
    • F01N11/00—Monitoring or diagnostic devices for exhaust-gas treatment apparatus, e.g. for catalytic activity
    • F01N11/007—Monitoring or diagnostic devices for exhaust-gas treatment apparatus, e.g. for catalytic activity the diagnostic devices measuring oxygen or air concentration 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
    • F01N9/00—Electrical control of exhaust gas treating apparatus
    • F01N9/005—Electrical control of exhaust gas treating apparatus using models instead of sensors to determine operating characteristics of exhaust systems, e.g. calculating catalyst temperature instead of measuring it directly
    • 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
    • F01N2900/06—Parameters used for exhaust control or diagnosing
    • F01N2900/16—Parameters used for exhaust control or diagnosing said parameters being related to the exhaust apparatus, e.g. particulate filter or catalyst
    • F01N2900/1624—Catalyst oxygen storage capacity
    • 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)
  • Analytical Chemistry (AREA)
  • Exhaust Gas After Treatment (AREA)

Abstract

The application discloses a method, a device and equipment for diagnosing the efficiency of a three-way catalyst, wherein the method comprises the following steps: firstly, when a target three-way catalyst meets an enabling condition of passive diagnosis, oxygen storage amount of the passive diagnosis is calculated, and when an interruption condition is met, the calculation of the oxygen storage amount under the passive diagnosis is interrupted; then when judging that the oxygen storage amount calculation result of passive diagnosis is smaller than the lower limit value, adding active diagnosis, then when the calculated excess air coefficient value of the post-oxygen test is not smaller than the preset limit value, firstly reducing the excess air coefficient value to the limit value of active diagnosis control reduction, then concentrating to the limit value of active diagnosis control concentration, then reducing the excess air coefficient value and starting to calculate the oxygen storage amount of active diagnosis, and further when judging that the oxygen storage amount calculation result of active diagnosis is smaller than the lower limit value of the oxygen storage amount of active diagnosis, reporting a low-efficiency fault; or when the lower limit value is not less than the lower limit value, the diagnosis is carried out again, so that the accuracy and the stability of the diagnosis result are improved through timely switching between passive diagnosis and active diagnosis.

Description

Three-way catalyst efficiency diagnosis method, device and equipment
Technical Field
The application relates to the technical field of vehicles, in particular to a method, a device and equipment for improving exhaust temperature of an engine.
Background
The Three-Way Catalyst (TWC) is used as a core component for aftertreatment of a natural gas engine, the emission level of the engine is determined by the efficiency of the TWC, and the efficiency diagnosis of the Three-Way Catalyst is a reasonable measure for judging the service life of the Three-Way Catalyst.
Passive diagnostics is generally the preferred option for three-way catalyst diagnostics to meet the current developmental requirements for low precious metal aftertreatment. However, the stability of passive diagnosis is greatly influenced by the running condition of the whole vehicle, and the stability is obviously inferior to that of an active diagnosis mode, so that the problem of false alarm and failure in the market is easily caused. However, the current active diagnostic logic needs to change the optimal control of the vehicle, increase the emissions, affect the emissions of the whole vehicle, and cannot ensure that the states of the catalysts are consistent when the oxygen storage amount starts to be calculated, so that the calculation deviation exists.
Therefore, how to improve the accuracy and stability of the efficiency diagnosis of the three-way catalyst becomes a problem to be solved urgently at present.
Disclosure of Invention
In order to solve the problems, the application provides a method, a device and equipment for diagnosing the efficiency of a three-way catalyst, which can effectively improve the accuracy and the stability of the efficiency diagnosis of the three-way catalyst, and the specific technical scheme is as follows:
in a first aspect, the present application provides a three-way catalyst efficiency diagnostic method, the method comprising:
acquiring operation data of a target three-way catalyst, and judging whether the operation data meets the enabling condition of passive diagnosis;
if so, starting to calculate the oxygen storage amount of the passive diagnosis, and interrupting the oxygen storage amount calculation under the passive diagnosis when judging that a preset passive diagnosis interruption condition is met to obtain an oxygen storage amount calculation result of the passive diagnosis;
when the calculated result of the oxygen storage amount of the passive diagnosis is judged to be smaller than the lower limit value of the oxygen storage amount of the passive diagnosis, the active diagnosis is added to perform auxiliary judgment on the target three-way catalyst;
when the calculated excess air coefficient value of the post-oxygen test is not less than the preset limit value, firstly, the reduction is carried out to the limit value of the excess air coefficient value of the post-oxygen test of the active diagnosis control reduction, then, the concentration is carried out to the limit value of the excess air coefficient value of the post-oxygen test of the active diagnosis control enrichment, then, the reduction is carried out, the oxygen storage amount of the active diagnosis is calculated, and the oxygen storage amount calculation result of the active diagnosis is obtained;
when the calculated result of the oxygen storage amount of the active diagnosis is judged to be smaller than the lower limit value of the oxygen storage amount of the active diagnosis, a fault that the target three-way catalyst is low in efficiency is reported; or when the calculated result of the oxygen storage amount of the active diagnosis is judged to be not less than the lower limit value of the oxygen storage amount of the active diagnosis, the operation data of the target three-way catalyst and the subsequent steps are re-executed until the accurate diagnosis of the efficiency of the target three-way catalyst is completed.
In an alternative implementation, the operational data at which the target three-way catalyst is located includes the target three-way catalyst bed temperature, a front oxygen sensor signal, a rear oxygen sensor signal, and an engine speed.
In an alternative implementation, the passive diagnostic interrupt condition includes one or more of the following conditions:
the rising slope of a signal of the throttle position sensor is greater than a preset slope limit value;
the signal reduction change rate of the throttle valve position sensor exceeds a preset change rate limit value in the calculation process;
the opening degree of the throttle valve is continuously lower than the preset lower limit value.
In an alternative implementation, the preset limit is 0.998.
In a second aspect, the present application provides a three-way catalyst efficiency diagnostic apparatus comprising:
the acquisition unit is used for acquiring the operation data of the target three-way catalyst and judging whether the operation data meets the enabling condition of passive diagnosis or not;
the interruption unit is used for starting to calculate the oxygen storage amount of the passive diagnosis if the operation data meets the enabling condition of the passive diagnosis, and interrupting the oxygen storage amount calculation under the passive diagnosis when the operation data meets the preset passive diagnosis interruption condition to obtain the oxygen storage amount calculation result of the passive diagnosis;
the increasing unit is used for increasing active diagnosis to perform auxiliary judgment on the target three-way catalyst when judging that the oxygen storage amount calculation result of the passive diagnosis is smaller than the lower limit value of the oxygen storage amount of the passive diagnosis;
the control unit is used for firstly diluting the calculated excess air coefficient value of the post-oxygen test to the excess air coefficient value limit value of the post-oxygen test for active diagnosis control of dilution and then concentrating the calculated excess air coefficient value limit value of the post-oxygen test for active diagnosis control of concentration when the calculated excess air coefficient value of the post-oxygen test is not less than the preset limit value, and then carrying out dilution and starting to calculate the oxygen storage amount of the active diagnosis to obtain the oxygen storage amount calculation result of the active diagnosis;
the diagnosis unit is used for reporting the fault that the efficiency of the target three-way catalyst is low when the calculated result of the oxygen storage amount of the active diagnosis is judged to be smaller than the lower limit value of the oxygen storage amount of the active diagnosis; or when the calculated result of the oxygen storage amount of the active diagnosis is judged to be not less than the lower limit value of the oxygen storage amount of the active diagnosis, the obtaining unit, the interrupting unit, the adding unit and the control unit are called and executed again until the accurate diagnosis of the efficiency of the target three-way catalyst is completed.
In an alternative implementation, the operational data at which the target three-way catalyst is located includes the target three-way catalyst bed temperature, a front oxygen sensor signal, a rear oxygen sensor signal, and an engine speed.
In an alternative implementation, the passive diagnostic interrupt condition includes one or more of the following conditions:
the rising slope of a signal of the throttle position sensor is greater than a preset slope limit value;
the signal reduction change rate of the throttle valve position sensor exceeds a preset change rate limit value in the calculation process;
the opening degree of the throttle valve is continuously lower than the preset lower limit value.
In an alternative implementation, the preset limit is 0.998.
The embodiment of the present application further provides a three-way catalyst efficiency diagnosis apparatus, including: a processor, a memory, a system bus;
the processor and the memory are connected through the system bus;
the memory is configured to store one or more programs, the one or more programs including instructions, which when executed by the processor, cause the processor to perform any one implementation of the three-way catalyst efficiency diagnostic method described above.
The embodiment of the application also provides a computer-readable storage medium, wherein the computer-readable storage medium stores instructions, and when the instructions are run on the terminal device, the terminal device is enabled to execute any implementation manner of the three-way catalyst efficiency diagnosis method.
In the method for diagnosing the efficiency of the three-way catalyst, firstly, operation data of a target three-way catalyst is obtained, whether the operation data meet enabling conditions of passive diagnosis or not is judged, if yes, oxygen storage amount of the passive diagnosis is calculated, and when judging that preset passive diagnosis interruption conditions are met, oxygen storage amount calculation under the passive diagnosis is interrupted, and an oxygen storage amount calculation result of the passive diagnosis is obtained; then when judging that the oxygen storage amount calculation result of the passive diagnosis is smaller than the lower oxygen storage amount limit value of the passive diagnosis, adding active diagnosis to perform auxiliary judgment on a target three-way catalyst, then when the calculated excess air coefficient value of the post-oxygen test is not smaller than the preset limit value, firstly reducing the calculated excess air coefficient value to the excess air coefficient value limit value of the post-oxygen test for active diagnosis control of reduction, then concentrating the calculated excess air coefficient value limit value to the excess air coefficient value limit value of the post-oxygen test for active diagnosis control of concentration, then reducing the calculated excess air coefficient value and starting to calculate the oxygen storage amount of the active diagnosis to obtain the oxygen storage amount calculation result of the active diagnosis, and then when judging that the oxygen storage amount calculation result of the active diagnosis is smaller than the lower oxygen storage amount limit value of the active diagnosis, reporting the fault of low efficiency of the target three-way catalyst; or when the calculated result of the oxygen storage amount of the active diagnosis is judged to be not less than the lower limit value of the oxygen storage amount of the active diagnosis, the operation data and the subsequent steps of the target three-way catalyst are obtained again until the accurate diagnosis of the efficiency of the target three-way catalyst is completed, so that the accuracy of the calculated result of the oxygen storage amount and the fault diagnosis stability can be improved and the misjudgment risk can be reduced by timely switching between the passive diagnosis and the active diagnosis.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive labor.
FIG. 1 is a schematic flow chart of a method for diagnosing efficiency of a three-way catalyst according to an embodiment of the present disclosure;
FIG. 2 is a flow chart illustrating a three-way catalyst efficiency diagnostic method provided by an embodiment of the present application;
fig. 3 is a schematic structural diagram of a three-way catalyst efficiency diagnostic apparatus according to an embodiment of the present application.
Detailed Description
The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
In order to facilitate understanding of the technical solutions provided in the present application, the following briefly describes the research background of the technical solutions in the present application.
As is well known in the background, passive diagnostics are currently the preferred option for three-way catalyst diagnostics to meet the evolving demands of low precious metal aftertreatment. However, the stability of passive diagnosis is greatly influenced by the running condition of the whole vehicle, and the stability is obviously inferior to that of an active diagnosis mode, so that the problem of false alarm and failure in the market is easily caused. However, the current active diagnostic logic needs to change the optimal control of the vehicle, increase emissions, affect the overall vehicle emissions, and cannot ensure that the catalyst states are consistent when the oxygen storage amount starts to be calculated, which causes calculation deviation, so how to improve the accuracy and stability of the efficiency diagnosis of the three-way catalyst becomes a problem to be solved urgently at present.
Based on the method, the device and the equipment, the efficiency diagnosis method, the device and the equipment for the three-way catalyst are provided, and are used for improving the accuracy and the stability of the efficiency diagnosis result of the three-way catalyst and greatly reducing the risk of misinformation of low-efficiency faults of the three-way catalyst through timely switching of passive diagnosis and active diagnosis.
The three-way catalyst efficiency diagnosis method provided by the embodiments of the present application will be described in detail below with reference to the accompanying drawings. Referring to fig. 1, which shows a flowchart of a method for greatly reducing the risk of an inefficient failure of a market false-positive three-way catalyst according to an embodiment of the present application, the embodiment may include the following steps:
s101: and acquiring the operation data of the target three-way catalyst, and judging whether the operation data meets the enabling condition of passive diagnosis.
In the present embodiment, any one of the three-way catalysts that achieves the efficiency diagnosis by the embodiments of the present application is defined as a target three-way catalyst. To achieve efficient diagnosis of the efficiency of a target three-way catalyst to improve the accuracy and stability of the diagnosis result. Firstly, the operation data of the target three-way catalyst is required to be acquired, and whether the operation data meets the enabling condition of passive diagnosis or not is judged.
In an optional implementation manner, in this embodiment, the operation data of the target three-way catalyst includes, but is not limited to, a bed temperature of the target three-way catalyst, a signal of the front oxygen sensor, a signal of the rear oxygen sensor, an engine speed, and the like.
In this way, when the bed temperature of the target three-way catalyst, the signal of the front oxygen sensor, the signal of the rear oxygen sensor, or the engine speed, etc., satisfy the enabling condition of the passive diagnosis, for example, when the temperature is higher than 400 degrees, it indicates that the operation data where the target three-way catalyst is located satisfies the enabling condition of the passive diagnosis, and the subsequent step S102 may be continuously executed.
S102: if so, starting to calculate the oxygen storage amount of the passive diagnosis, and interrupting the oxygen storage amount calculation under the passive diagnosis when judging that a preset passive diagnosis interruption condition is met to obtain an oxygen storage amount calculation result of the passive diagnosis.
In this embodiment, if it is determined through step S101 that the operation data of the target three-way catalyst satisfies the enabling condition of the passive diagnosis, the calculation of the oxygen storage amount (OSC) of the passive diagnosis may be further started, and when it is determined that the preset passive diagnosis interruption condition is satisfied, the calculation of the oxygen storage amount in the passive diagnosis may be interrupted to obtain the oxygen storage amount calculation result of the passive diagnosis (which is defined herein as OSC)Passive)。
In an optional implementation manner, in the present embodiment, the passive diagnosis interrupt condition includes one or more of the following conditions:
(1) the slope of the rise of the signal from the Throttle Position Sensor (TPS) is greater than a preset slope limit.
(2) And in the calculation process, the signal reduction change rate of the throttle position sensor TPS exceeds a preset change rate limit value.
(3) The opening degree of the throttle valve TPS is continuously lower than a preset lower limit value (defined as T herein)Lower limit of)。
Therefore, when any one of the three passive diagnosis interruption conditions is met, the oxygen storage amount calculation under the working condition influencing the passive diagnosis calculation precision is interrupted, so that the accuracy of the oxygen storage amount calculation result is improved.
S103: and when the calculated result of the oxygen storage amount of the passive diagnosis is judged to be smaller than the lower limit value of the oxygen storage amount of the passive diagnosis, the active diagnosis is added to perform auxiliary judgment on the target three-way catalyst.
In the present embodiment, the passively diagnosed oxygen storage amount calculation result OSC is obtained by step S102PassiveThen, there is a further need to judge the oxygen storage amount calculation result OSC of the passive diagnosisPassiveWhether or not it is less than the lower oxygen storage limit for passive diagnosis (defined herein as OSC)Passive limit valueAnd specific values can be set according to actual conditions, the embodiment of the application does not limit the values, for example, the values can be defined as 3, and the like).
S104: when the calculated excess air coefficient value of the post-oxygen test is not less than the preset limit value, firstly, the reduction is carried out to the excess air coefficient value limit value of the post-oxygen test of the active diagnosis control reduction, then, the concentration is carried out to the excess air coefficient value limit value of the post-oxygen test of the active diagnosis control enrichment, then, the reduction is carried out, the oxygen storage amount of the active diagnosis is calculated, and the oxygen storage amount calculation result of the active diagnosis is obtained.
In the present embodiment, after the auxiliary determination of the target three-way catalyst by adding the active diagnosis in step S103, it is further necessary to determine the value of the excess air coefficient of the post-oxygen test (defined herein as λPost oxygen) Whether the value is smaller than a preset limit value (a specific value of the preset limit value may be set according to an actual situation, which is not limited in the embodiment of the present application, for example, it may be defined as 0.998, etc.), if so, λ needs to be determinedPost oxygenDerating to λ for active diagnostic control deratingPost oxygenA limit value (defined herein as λ)Post oxygen Lean) Re-enrichment to lambda for active diagnostic control enrichmentPost oxygenA limit value (defined herein as λ)Post-oxygen Rich) Then, the oxygen storage amount of the active diagnosis is calculated by performing the reduction and starting to calculate the oxygen storage amount of the active diagnosis, and the oxygen storage amount calculation result of the active diagnosis (which is defined as OSC herein) is obtainedActive) For performing the following step S105.
S105: when the calculated result of the oxygen storage amount of the active diagnosis is judged to be smaller than the lower limit value of the oxygen storage amount of the active diagnosis, a fault that the efficiency of the target three-way catalyst is low is reported; or when the calculated result of the oxygen storage amount of the active diagnosis is judged to be not less than the lower limit value of the oxygen storage amount of the active diagnosis, the operation data of the target three-way catalyst and the subsequent steps are re-executed until the accurate diagnosis of the efficiency of the target three-way catalyst is completed.
In the present embodiment, the oxygen storage amount calculation result OSC of the active diagnosis is obtained in step S104ActiveThen, it is further necessary to judge the oxygen storage amount calculation result OSC of the active diagnosisActiveWhether or not it is less than the lower oxygen storage limit for active diagnostics (defined herein as OSC)Active limitThe specific value can be set according to the actual situation, the value is not limited in the embodiment of the application, for example, the value can be defined as 3.5, and the like), and if the value is determined to be the value, a fault that the target three-way catalyst is low in efficiency is reported; otherwise, if not, the steps S101-S104 are executed again until the accurate diagnosis of the target three-way catalyst efficiency is completed.
Next, for ease of understanding, reference is now made to the flow chart of a three-way catalyst efficiency diagnostic method illustrated in FIG. 2. The overall implementation process of the three-way catalyst efficiency diagnosis method provided by the embodiment of the application is introduced.
As shown in fig. 2, the overall implementation process of the embodiment of the present application is as follows: firstly, acquiring operation data of a target three-way catalyst, judging whether the operation data meets an enabling condition of passive diagnosis, if so, starting to calculate the oxygen storage amount of the passive diagnosis, and interrupting the oxygen storage amount calculation under the passive diagnosis when judging that a preset passive diagnosis interruption condition is met to obtain an oxygen storage amount calculation result of the passive diagnosis; then, whether the calculated result of the oxygen storage amount of the passive diagnosis is effective is judged, if the calculated result is over large or over small, and the like, if the calculated result is effective, the calculated result OSC of the oxygen storage amount of the passive diagnosis is outputPassiveThen judging the calculated oxygen storage amount OSC of the passive diagnosisPassiveLower oxygen storage limit OSC less than passive diagnosisPassive limit valueIf yes, adding active diagnosis to carry out auxiliary judgment on the target three-way catalyst, and then judging the excess air coefficient value lambda of the post-oxygen testPost oxygenIf the pressure is less than the preset limit value, firstly carrying out mixed gas lean reduction to lambda for actively diagnosing and controlling lean reductionPost oxygenLimit value lambdaPost oxygen LeanRe-enrichment of the mixture to lambda for active diagnostic control enrichmentPost oxygenLimit value lambdaPost oxygenRichThen, the mixed gas is diluted and the oxygen storage amount of the active diagnosis is calculated until the oxygen storage amount of the active diagnosis is calculated, and an oxygen storage amount calculation result OSC of the active diagnosis is obtainedActiveFurther determining the oxygen storage amount calculation result OSCActiveIf the oxygen storage quantity is effective, outputting an oxygen storage quantity calculation result OSC of active diagnosisActiveFinally, judging the oxygen storage quantity calculation result OSC of the active diagnosisActiveWhether or not it is less than the lower oxygen storage limit OSC of the active diagnosisActive limitIf so, reporting a fault that the target three-way catalyst is low in efficiency; and if not, re-executing the operation data and subsequent steps of obtaining the target three-way catalyst until the accurate diagnosis of the efficiency of the target three-way catalyst is completed, wherein the specific implementation process is shown in steps S101-S105.
In summary, in the three-way catalyst efficiency diagnosis method provided by the application, firstly, the operation data of the target three-way catalyst is obtained, whether the operation data meets the enabling condition of passive diagnosis or not is judged, if yes, the oxygen storage amount of the passive diagnosis is calculated, and when the preset passive diagnosis interruption condition is judged to be met, the calculation of the oxygen storage amount under the passive diagnosis is interrupted, and the oxygen storage amount calculation result of the passive diagnosis is obtained; then when judging that the oxygen storage amount calculation result of the passive diagnosis is smaller than the lower oxygen storage amount limit value of the passive diagnosis, adding active diagnosis to perform auxiliary judgment on a target three-way catalyst, then when the calculated excess air coefficient value of the post-oxygen test is not smaller than the preset limit value, firstly reducing the calculated excess air coefficient value to the excess air coefficient value limit value of the post-oxygen test for active diagnosis control of reduction, then concentrating the calculated excess air coefficient value limit value to the excess air coefficient value limit value of the post-oxygen test for active diagnosis control of concentration, then reducing the calculated excess air coefficient value and starting to calculate the oxygen storage amount of the active diagnosis to obtain the oxygen storage amount calculation result of the active diagnosis, and then when judging that the oxygen storage amount calculation result of the active diagnosis is smaller than the lower oxygen storage amount limit value of the active diagnosis, reporting the fault of low efficiency of the target three-way catalyst; or when the calculated result of the oxygen storage amount of the active diagnosis is judged to be not less than the lower limit value of the oxygen storage amount of the active diagnosis, the operation data and the subsequent steps of the target three-way catalyst are obtained again until the accurate diagnosis of the efficiency of the target three-way catalyst is completed, so that the accuracy of the calculated result of the oxygen storage amount and the fault diagnosis stability can be improved and the misjudgment risk can be reduced by timely switching between the passive diagnosis and the active diagnosis.
The above embodiments describe the technical solutions of the methods of the present application in detail, and accordingly, the present application further provides a device for controlling the temperature of the engine exhaust, which is described below.
Referring to fig. 3, fig. 3 is a structural diagram of a three-way catalyst efficiency diagnosis apparatus provided in an embodiment of the present application, and as shown in fig. 3, the apparatus includes:
an obtaining unit 301, configured to obtain operation data of a target three-way catalyst, and determine whether the operation data meets an enabling condition of passive diagnosis;
an interruption unit 302, configured to start calculating an oxygen storage amount for passive diagnosis if it is determined that the operation data meets an enabling condition of passive diagnosis, and interrupt oxygen storage amount calculation under passive diagnosis when it is determined that a preset passive diagnosis interruption condition is met, to obtain an oxygen storage amount calculation result for passive diagnosis;
an increasing unit 303, configured to increase active diagnosis to perform auxiliary determination on the target three-way catalyst when it is determined that the oxygen storage amount calculation result of the passive diagnosis is smaller than the lower limit value of the oxygen storage amount of the passive diagnosis;
a control unit 304, configured to, when the calculated excess air coefficient value of the post-oxygen test is not less than the preset limit, firstly dilute the calculated excess air coefficient value to the excess air coefficient value limit of the post-oxygen test for active diagnosis control of the subtraction, then enrich the calculated excess air coefficient value to the excess air coefficient value limit of the post-oxygen test for active diagnosis control of the enrichment, then perform the subtraction, and start to calculate the oxygen storage amount for active diagnosis, so as to obtain an oxygen storage amount calculation result for active diagnosis;
a diagnosis unit 305, configured to report a failure that the target three-way catalyst is inefficient when it is determined that the calculation result of the oxygen storage amount of the active diagnosis is smaller than the lower limit value of the oxygen storage amount of the active diagnosis; or when the oxygen storage amount calculation result of the active diagnosis is judged to be not less than the lower limit value of the oxygen storage amount of the active diagnosis, the obtaining unit 301, the interrupting unit 302, the increasing unit 303 and the control unit 304 are called again to be executed until the accurate diagnosis of the efficiency of the target three-way catalyst is completed.
Optionally, the operating data at which the target three-way catalyst is located includes the target three-way catalyst bed temperature, a front oxygen sensor signal, a rear oxygen sensor signal, and an engine speed.
Optionally, the passive diagnostic interrupt condition comprises one or more of the following conditions:
the rising slope of a signal of the throttle position sensor is greater than a preset slope limit value;
the signal reduction change rate of the throttle valve position sensor exceeds a preset change rate limit value in the calculation process;
the opening degree of the throttle valve is continuously lower than the preset lower limit value.
Optionally, the preset limit is 0.998.
In this way, in the three-way catalyst efficiency diagnosis device provided by the application, firstly, the operation data of the target three-way catalyst is obtained, whether the operation data meets the enabling condition of passive diagnosis or not is judged, if yes, the oxygen storage amount of the passive diagnosis is calculated, and when the preset passive diagnosis interruption condition is judged to be met, the oxygen storage amount calculation under the passive diagnosis is interrupted, and the oxygen storage amount calculation result of the passive diagnosis is obtained; then when judging that the oxygen storage amount calculation result of the passive diagnosis is smaller than the lower oxygen storage amount limit value of the passive diagnosis, adding active diagnosis to perform auxiliary judgment on a target three-way catalyst, then when the calculated excess air coefficient value of the post-oxygen test is not smaller than the preset limit value, firstly reducing the calculated excess air coefficient value to the excess air coefficient value limit value of the post-oxygen test for active diagnosis control of reduction, then concentrating the calculated excess air coefficient value limit value to the excess air coefficient value limit value of the post-oxygen test for active diagnosis control of concentration, then reducing the calculated excess air coefficient value and starting to calculate the oxygen storage amount of the active diagnosis to obtain the oxygen storage amount calculation result of the active diagnosis, and then when judging that the oxygen storage amount calculation result of the active diagnosis is smaller than the lower oxygen storage amount limit value of the active diagnosis, reporting the fault of low efficiency of the target three-way catalyst; or when the calculated result of the oxygen storage amount of the active diagnosis is judged to be not less than the lower limit value of the oxygen storage amount of the active diagnosis, the operation data and the subsequent steps of the target three-way catalyst are obtained again until the accurate diagnosis of the efficiency of the target three-way catalyst is completed, so that the accuracy of the calculated result of the oxygen storage amount and the fault diagnosis stability can be improved and the misjudgment risk can be reduced by timely switching between the passive diagnosis and the active diagnosis.
Further, an embodiment of the present application also provides a three-way catalyst efficiency diagnosis apparatus, including: a processor, a memory, a system bus;
the processor and the memory are connected through the system bus;
the memory is configured to store one or more programs, the one or more programs including instructions, which when executed by the processor, cause the processor to perform any of the implementation methods of the three-way catalyst efficiency diagnostic method described above.
Further, an embodiment of the present application also provides a computer-readable storage medium, where instructions are stored in the computer-readable storage medium, and when the instructions are executed on a terminal device, the instructions cause the terminal device to execute any implementation method of the three-way catalyst efficiency diagnosis method.
It should be noted that, in the present specification, the embodiments are 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 system or the device disclosed by the embodiment, the description is simple because the system or the device corresponds to the method disclosed by the embodiment, and the relevant points can be referred to the method part for description.
It is further 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 steps of a method or algorithm described in connection with the embodiments disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in Random Access Memory (RAM), memory, Read Only Memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present application. 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 application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (10)

1. A three-way catalyst efficiency diagnostic method, characterized in that the method comprises:
acquiring operation data of a target three-way catalyst, and judging whether the operation data meets the enabling condition of passive diagnosis;
if so, starting to calculate the oxygen storage amount of the passive diagnosis, and interrupting the oxygen storage amount calculation under the passive diagnosis when judging that a preset passive diagnosis interruption condition is met to obtain an oxygen storage amount calculation result of the passive diagnosis;
when the calculated result of the oxygen storage amount of the passive diagnosis is judged to be smaller than the lower limit value of the oxygen storage amount of the passive diagnosis, the active diagnosis is added to perform auxiliary judgment on the target three-way catalyst;
when the calculated excess air coefficient value of the post-oxygen test is not less than the preset limit value, firstly, the reduction is carried out to the limit value of the excess air coefficient value of the post-oxygen test of the active diagnosis control reduction, then, the concentration is carried out to the limit value of the excess air coefficient value of the post-oxygen test of the active diagnosis control enrichment, then, the reduction is carried out, the oxygen storage amount of the active diagnosis is calculated, and the oxygen storage amount calculation result of the active diagnosis is obtained;
when the calculated result of the oxygen storage amount of the active diagnosis is judged to be smaller than the lower limit value of the oxygen storage amount of the active diagnosis, a fault that the target three-way catalyst is low in efficiency is reported; or when the calculated result of the oxygen storage amount of the active diagnosis is judged to be not less than the lower limit value of the oxygen storage amount of the active diagnosis, the operation data of the target three-way catalyst and the subsequent steps are re-executed until the accurate diagnosis of the efficiency of the target three-way catalyst is completed.
2. The method of claim 1, wherein the operating data at which the target three-way catalyst is located includes the target three-way catalyst bed temperature, a front oxygen sensor signal, a rear oxygen sensor signal, and an engine speed.
3. The method of claim 1, wherein the passive diagnostic interrupt condition comprises one or more of the following conditions:
the rising slope of a signal of the throttle position sensor is greater than a preset slope limit value;
the signal reduction change rate of the throttle valve position sensor exceeds a preset change rate limit value in the calculation process;
the opening degree of the throttle valve is continuously lower than the preset lower limit value.
4. The method of claim 1, wherein the preset limit is 0.998.
5. A three-way catalyst efficiency diagnostic apparatus, characterized in that the apparatus comprises:
the acquisition unit is used for acquiring the operation data of the target three-way catalyst and judging whether the operation data meets the enabling condition of passive diagnosis or not;
the interruption unit is used for starting to calculate the oxygen storage amount of the passive diagnosis if the operation data meets the enabling condition of the passive diagnosis, and interrupting the oxygen storage amount calculation under the passive diagnosis when the operation data meets the preset passive diagnosis interruption condition to obtain the oxygen storage amount calculation result of the passive diagnosis;
the increasing unit is used for increasing active diagnosis to perform auxiliary judgment on the target three-way catalyst when judging that the oxygen storage amount calculation result of the passive diagnosis is smaller than the lower limit value of the oxygen storage amount of the passive diagnosis;
the control unit is used for firstly diluting the calculated excess air coefficient value of the post-oxygen test to the excess air coefficient value limit value of the post-oxygen test for active diagnosis control of dilution and then concentrating the calculated excess air coefficient value limit value of the post-oxygen test for active diagnosis control of concentration when the calculated excess air coefficient value of the post-oxygen test is not less than the preset limit value, and then carrying out dilution and starting to calculate the oxygen storage amount of the active diagnosis to obtain the oxygen storage amount calculation result of the active diagnosis;
the diagnosis unit is used for reporting the fault that the efficiency of the target three-way catalyst is low when the calculated result of the oxygen storage amount of the active diagnosis is judged to be smaller than the lower limit value of the oxygen storage amount of the active diagnosis; or when the calculated result of the oxygen storage amount of the active diagnosis is judged to be not less than the lower limit value of the oxygen storage amount of the active diagnosis, the obtaining unit, the interrupting unit, the adding unit and the control unit are called and executed again until the accurate diagnosis of the efficiency of the target three-way catalyst is completed.
6. The apparatus of claim 5, wherein the operating data at which the target three-way catalyst is located includes the target three-way catalyst bed temperature, a front oxygen sensor signal, a rear oxygen sensor signal, and an engine speed.
7. The apparatus of claim 5, wherein the passive diagnostic interrupt condition comprises one or more of:
the rising slope of a signal of the throttle position sensor is greater than a preset slope limit value;
the signal reduction change rate of the throttle valve position sensor exceeds a preset change rate limit value in the calculation process;
the opening degree of the throttle valve is continuously lower than the preset lower limit value.
8. The apparatus of claim 5, wherein the preset limit is 0.998.
9. A three-way catalyst efficiency diagnostic apparatus characterized by comprising: a processor, a memory, a system bus;
the processor and the memory are connected through the system bus;
the memory is to store one or more programs, the one or more programs comprising instructions, which when executed by the processor, cause the processor to perform the method of any of claims 1-4.
10. A computer-readable storage medium having stored therein instructions that, when executed on a terminal device, cause the terminal device to perform the method of any one of claims 1-4.
CN202111554314.2A 2021-12-17 2021-12-17 Three-way catalyst efficiency diagnosis method, device and equipment Active CN114233446B (en)

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