CN112983613A - Nitrogen-oxygen sensor fault judgment method and related device - Google Patents
Nitrogen-oxygen sensor fault judgment method and related device Download PDFInfo
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- CN112983613A CN112983613A CN202110333995.3A CN202110333995A CN112983613A CN 112983613 A CN112983613 A CN 112983613A CN 202110333995 A CN202110333995 A CN 202110333995A CN 112983613 A CN112983613 A CN 112983613A
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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
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
- F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
- F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
- F01N3/18—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control
- F01N3/20—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control specially adapted for catalytic conversion ; Methods of operation or control of catalytic converters
- F01N3/2066—Selective catalytic reduction [SCR]
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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
- F01N2560/00—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics
- F01N2560/02—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics the means being an exhaust gas sensor
- F01N2560/026—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics the means being an exhaust gas sensor for measuring or detecting NOx
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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
- F01N2570/00—Exhaust treating apparatus eliminating, absorbing or adsorbing specific elements or compounds
- F01N2570/14—Nitrogen oxides
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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
- F01N2610/00—Adding substances to exhaust gases
- F01N2610/02—Adding substances to exhaust gases the substance being ammonia or urea
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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
- 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
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- 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
Abstract
The application discloses a method and a device for judging faults of a nitrogen-oxygen sensor, wherein when a diesel particle filtering system enters a cooling stage, a nitrogen oxide reducing agent is controlled to stop spraying; then, comparing a first nitrogen oxygen value measured by the upstream nitrogen oxygen sensor with a preset value, and judging whether the upstream nitrogen oxygen sensor fails; and when the upstream nitrogen-oxygen sensor has no fault, comparing the nitrogen-oxygen value measured by the upstream nitrogen-oxygen sensor with the nitrogen-oxygen value measured by the downstream sensor to judge whether the downstream nitrogen-oxygen sensor has the fault. So, the scheme that this application embodiment provided can judge comparatively accurately whether trouble of upper reaches nitrogen oxygen sensor and low reaches nitrogen oxygen sensor to guarantee the accuracy of the nitrogen oxygen value of upper reaches nitrogen oxygen sensor and low reaches nitrogen oxygen sensor measurement, and then guarantee the accuracy that the reductant added.
Description
Technical Field
The application relates to the field of vehicles, in particular to a fault judgment method and a relevant device for a nitrogen-oxygen sensor.
Background
Currently, Diesel Particulate Filter (DPF) systems generally use an upstream nox sensor and a downstream nox sensor to simultaneously detect nox values in exhaust gas of vehicles and diagnose the efficiency of nox Reduction conversion in a Selective Catalytic Reduction (SCR) process in the exhaust gas based on the nox values, thereby controlling the amount of urea (reductant) added.
However, the upstream nox sensor and the downstream nox sensor sometimes fail, and the nox value measured by the upstream nox sensor and/or the downstream nox sensor is inaccurate, and further the diesel particulate filtering system cannot accurately diagnose the reduction conversion efficiency of nox in the exhaust gas, and the amount of urea (reducing agent) added is inaccurate.
Disclosure of Invention
In order to solve the technical problem, the application provides a method and a related device for judging faults of a nitrogen-oxygen sensor, which are used for ensuring the accuracy of nitrogen-oxygen values measured by an upstream nitrogen-oxygen sensor and a downstream nitrogen-oxygen sensor.
In order to achieve the above purpose, the technical solutions provided in the embodiments of the present application are as follows:
the embodiment of the application provides a fault judgment method for a nitrogen oxygen sensor, which is applied to a diesel particle filtering system and comprises the following steps:
when the diesel particulate filter system enters a cooling stage, controlling the nitrogen oxide reducing agent to stop spraying;
during the cooling phase, obtaining a first nitrogen and oxygen value through an upstream nitrogen and oxygen sensor and obtaining a second nitrogen and oxygen value through a downstream nitrogen and oxygen sensor;
comparing the first nitrogen and oxygen value with a preset nitrogen and oxygen value, and judging whether the upstream nitrogen and oxygen sensor fails;
comparing the first nitrogen oxygen value with the preset nitrogen oxygen value, and comparing the first nitrogen oxygen value with the second nitrogen oxygen value to judge whether the downstream nitrogen oxygen sensor has faults or not; and the preset nitrogen and oxygen value is obtained according to the ideal model of the nitrogen and oxygen value in the cooling stage.
Optionally, the comparing the first nox value with a preset nox value to determine whether the upstream nox sensor is faulty includes:
when the difference value between the first nitrogen oxygen value and a preset nitrogen oxygen value exceeds a first preset range, judging that the upstream nitrogen oxygen sensor has a fault; the first preset range is obtained according to the ideal model of the nitrogen oxygen value of the cooling stage.
Optionally, the comparing the first nitrogen-oxygen value with the preset nitrogen-oxygen value and the first nitrogen-oxygen value with the second nitrogen-oxygen value to determine whether the downstream nitrogen-oxygen sensor fails includes:
when the difference value between the first nitrogen oxygen value and the preset nitrogen oxygen value is within the first preset range and the difference value between the first nitrogen oxygen value and the second nitrogen oxygen value exceeds a second preset range, judging that the downstream nitrogen oxygen sensor has a fault; the second preset range is smaller than the first preset range; the second preset range is obtained according to the ideal model of the nitrogen oxygen value of the cooling stage.
Optionally, the method further comprises:
and when the difference value between the first nitrogen oxygen value and the preset nitrogen oxygen value exceeds the first preset range, and the difference value between the second nitrogen oxygen value and the preset nitrogen oxygen value exceeds the first preset range, judging that the downstream nitrogen oxygen sensor has a fault.
Optionally, the obtaining a first nox value by an upstream nox sensor comprises:
taking the average value of the nitrogen and oxygen values measured by the upstream nitrogen and oxygen sensor within a preset time as a first nitrogen and oxygen value;
the obtaining a second NOx value by a downstream NOx sensor includes:
and taking the average value of the nitrogen and oxygen values measured by the downstream nitrogen and oxygen sensor in the preset time period as a second nitrogen and oxygen value.
Optionally, the determining the upstream NOx sensor fault includes:
judging faults of an upstream nitrogen-oxygen sensor, and inhibiting the diesel particle filtering system from diagnosing the conversion efficiency of nitrogen-oxygen compounds in tail gas according to a nitrogen-oxygen value obtained by the upstream nitrogen-oxygen sensor;
the method for judging the fault of the downstream nitrogen-oxygen sensor comprises the following steps:
and judging faults of the downstream nitrogen-oxygen sensor, and inhibiting the diesel particle filtering system from diagnosing the conversion efficiency of nitrogen-oxygen compounds in the tail gas according to the nitrogen-oxygen value obtained by the downstream nitrogen-oxygen sensor.
The embodiment of the application provides a nitrogen oxygen sensor fault judgment device, the device is applied to diesel particulate filter system, the device includes:
the control module is used for controlling the nitrogen oxide reducing agent to stop spraying when the diesel particulate filtering system enters a cooling stage;
an obtaining module, configured to obtain a first nitrogen-oxygen value by an upstream nitrogen-oxygen sensor and a second nitrogen-oxygen value by a downstream nitrogen-oxygen sensor during the cooling phase;
the upstream judgment module is used for comparing the first nitrogen and oxygen value with a preset nitrogen and oxygen value and judging whether the upstream nitrogen and oxygen sensor fails or not;
the downstream judging module is used for comparing the first nitrogen oxygen value with the preset nitrogen oxygen value, comparing the first nitrogen oxygen value with the second nitrogen oxygen value and judging whether the downstream nitrogen oxygen sensor has faults or not;
and the preset nitrogen and oxygen value is obtained according to the ideal model of the nitrogen and oxygen value in the cooling stage.
Optionally, the upstream determining module is specifically configured to:
when the difference value between the first nitrogen oxygen value and a preset nitrogen oxygen value exceeds a first preset range, judging that the upstream nitrogen oxygen sensor has a fault; the first preset range is obtained according to the ideal model of the nitrogen oxygen value of the cooling stage.
Optionally, the downstream determining module is specifically configured to:
when the difference value between the first nitrogen oxygen value and the preset nitrogen oxygen value is within the first preset range and the difference value between the first nitrogen oxygen value and the second nitrogen oxygen value exceeds a second preset range, judging that the downstream nitrogen oxygen sensor has a fault; the second preset range is smaller than the first preset range; the second preset range is obtained according to the ideal model of the nitrogen oxygen value of the cooling stage.
Optionally, the upstream determining module is specifically configured to:
when the difference value between the first nitrogen oxygen value and a preset nitrogen oxygen value exceeds a first preset range, judging that the upstream nitrogen oxygen sensor has a fault, and inhibiting the diesel particle filtering system from diagnosing the conversion efficiency of nitrogen oxides in tail gas according to the nitrogen oxygen value obtained by the upstream nitrogen oxygen sensor;
the downstream judgment module is specifically configured to:
and when the difference value of the first nitrogen oxygen value and the preset nitrogen oxygen value is in the first preset range and the difference value of the first nitrogen oxygen value and the second nitrogen oxygen value exceeds the second preset range, judging that the downstream nitrogen oxygen sensor has a fault, and inhibiting the diesel particle filtering system from diagnosing the conversion efficiency of nitrogen oxides in the tail gas according to the nitrogen oxygen value obtained by the downstream nitrogen oxygen sensor.
The embodiment of the application provides a diesel particle filtering system, which comprises the nitrogen-oxygen sensor fault judgment device, an upstream nitrogen-oxygen sensor and a downstream nitrogen-oxygen sensor;
the upstream nitrogen-oxygen sensor and the downstream nitrogen-oxygen sensor are respectively connected with the nitrogen-oxygen sensor fault judgment device.
According to the technical scheme, the method has the following beneficial effects:
the embodiment of the application provides a method and a device for judging faults of a nitrogen-oxygen sensor, wherein when a diesel particle filtering system enters a cooling stage, a nitrogen oxide reducing agent is controlled to stop spraying; then, comparing a first nitrogen oxygen value measured by the upstream nitrogen oxygen sensor with a preset value, and judging whether the upstream nitrogen oxygen sensor fails; and when the upstream nitrogen-oxygen sensor has no fault, comparing the nitrogen-oxygen value measured by the upstream nitrogen-oxygen sensor with the nitrogen-oxygen value measured by the downstream sensor to judge whether the downstream nitrogen-oxygen sensor has the fault. So, the scheme that this application embodiment provided can judge comparatively accurately whether trouble of upper reaches nitrogen oxygen sensor and low reaches nitrogen oxygen sensor to guarantee the accuracy of the nitrogen oxygen value of upper reaches nitrogen oxygen sensor and low reaches nitrogen oxygen sensor measurement, and then guarantee urea (reductant) and add the accuracy.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
FIG. 1 is a schematic flow chart illustrating a method for determining faults of a NOx sensor according to an embodiment of the present disclosure;
FIG. 2 is a schematic illustration of a park regeneration process of a diesel particulate filter system according to an embodiment of the present disclosure;
fig. 3 is a schematic structural diagram of a device for determining faults of a nox sensor according to an embodiment of the present application.
Detailed Description
In order to help better understand the scheme provided by the embodiment of the present application, before describing the method provided by the embodiment of the present application, a scenario of an application of the scheme of the embodiment of the present application is described.
Currently, diesel particulate filter systems generally use an upstream nox sensor and a downstream nox sensor to simultaneously detect the nox value in the exhaust gas of a vehicle and diagnose the reduction conversion efficiency of nox in the exhaust gas based on the nox value, thereby controlling the amount of urea (reducing agent) added. However, the upstream nox sensor and the downstream nox sensor sometimes fail, and the nox value measured by the upstream nox sensor and/or the downstream nox sensor is inaccurate, and further the diesel particulate filtering system cannot accurately diagnose the reduction conversion efficiency of nox in the exhaust gas, and the amount of urea (reducing agent) added is inaccurate.
In order to solve the above technical problem, an embodiment of the present application provides a method and a related apparatus for determining a fault of an upstream nox sensor, in which a first nox value measured by the upstream nox sensor is compared with a preset value, and whether a signal measured by the upstream nox sensor is accurate is determined; and when the upstream nitrogen-oxygen sensor measures accurately, comparing the nitrogen-oxygen value measured by the upstream nitrogen-oxygen sensor with the nitrogen-oxygen value measured by the downstream sensor, and judging whether the signal measured by the downstream nitrogen-oxygen sensor is accurate or not. So, the scheme that this application embodiment provided can judge comparatively accurately whether the nitrogen oxygen value that upstream nitrogen oxygen sensor and low reaches nitrogen oxygen sensor measured is accurate to guarantee the accuracy of the nitrogen oxygen value that upstream nitrogen oxygen sensor and low reaches nitrogen oxygen sensor measured, and then guarantee urea (reductant) and add the accuracy.
In order to make the aforementioned objects, features and advantages of the present application more comprehensible, embodiments accompanying the drawings are described in detail below.
Referring to fig. 1, the figure is a schematic flow chart of a method for determining a fault of a nox sensor according to an embodiment of the present application. As shown in fig. 1, a method for determining a malfunction of a nox sensor according to an embodiment of the present application is applied to a diesel particulate filter system, and the method includes:
s101: when the diesel particulate filter system enters a cooling stage, controlling the nitrogen oxide reducing agent to stop spraying;
s102: in the cooling stage, obtaining a first nitrogen oxygen value through an upstream nitrogen oxygen sensor and obtaining a second nitrogen oxygen value through a downstream nitrogen oxygen sensor;
s103: and comparing the first nitrogen and oxygen value with a preset nitrogen and oxygen value, and judging whether the upstream nitrogen and oxygen sensor fails.
S104: and comparing the first nitrogen oxygen value with a preset nitrogen oxygen value, and comparing the first nitrogen oxygen value with the second nitrogen oxygen value to judge whether the downstream nitrogen oxygen sensor has faults or not.
It should be noted that, in the embodiments of the present application, the preset nitrogen oxygen value is based onAnd obtaining an ideal model of the nitrogen oxygen value in the cooling stage. Referring to fig. 2, the parking regeneration process of a diesel particulate filter system according to an embodiment of the present disclosure is schematically illustrated. As shown in fig. 2, the diesel particulate filter system has a light-off phase, a DPF regeneration phase, and a cooling phase during a parking regeneration. In the cooling stage, the air inlet throttle valve is fully opened, the rotating speed is stable, the exhaust temperature is reduced, and NO isXThe pollutant discharge is stable. The method provided by the embodiment of the application controls the nitrogen oxygen reducing agent (urea) to stop spraying when the diesel particulate filter system enters the cooling stage. Thus, the nitrogen-oxygen value in the tail gas in the cooling stage is a relatively fixed value, and the method provided by the embodiment of the application can detect whether the upstream nitrogen-oxygen sensor and the downstream nitrogen-oxygen sensor are in failure or not by using the relatively fixed value (the preset nitrogen-oxygen value).
It should be noted that the ideal model of the nox value in the embodiment of the present application includes the normal fluctuation range of the nox value in the whole cooling stage after the nox reducing agent is stopped being injected when the diesel particulate filtering system enters the cooling stage. The ideal model of the nitrogen oxygen value in the embodiment of the present application may be obtained according to simulation or actual measurement of data, and the embodiment of the present application is not limited herein.
In the embodiment of the present application, it can be understood that, when there is no fault in the upstream nox sensor, it is determined that the first nox value measured by the upstream nox sensor is relatively accurate. Under the more accurate prerequisite of first nitrogen oxygen value, this application compares through first nitrogen oxygen value and second nitrogen oxygen value, can judge the trouble of low reaches nitrogen oxygen sensor relatively accurately. It is understood that, in the embodiment of the present application, since the first nitrogen oxygen value and the second nitrogen oxygen value are measured in the same cooling stage, there is a small error between the first nitrogen oxygen value and the second nitrogen oxygen value with respect to the preset nitrogen oxygen value. Therefore, the method provided by the embodiment of the application has no fault in the upstream nitrogen-oxygen sensor, and whether the downstream nitrogen-oxygen sensor has the fault can be accurately judged by comparing the first nitrogen-oxygen value with the second nitrogen-oxygen value.
The following describes in detail the comparative procedures in the examples of the present application by way of examples:
in this embodiment, as a possible implementation manner, comparing the first nox value with a preset nox value to determine whether the upstream nox sensor fails includes: when the difference value between the first nitrogen oxygen value and the preset nitrogen oxygen value exceeds a first preset range, judging that the upstream nitrogen oxygen sensor has a fault; the first predetermined range is obtained from an ideal model of the nitrogen oxygen value during the cooling phase.
Accordingly, in the embodiment of the present application, as a possible implementation manner, comparing the first value of nitrogen and oxygen with a preset value of nitrogen and oxygen, and comparing the first value of nitrogen and oxygen with the second value of nitrogen and oxygen, and determining whether the downstream nitrogen and oxygen sensor fails includes: when the difference value between the first nitrogen oxygen value and the preset nitrogen oxygen value is within a first preset range and the difference value between the first nitrogen oxygen value and the second nitrogen oxygen value exceeds a second preset range, judging that the downstream nitrogen oxygen sensor has a fault; the second preset range is smaller than the first preset range; the second predetermined range is obtained from an ideal model of the nitrogen oxygen value during the cooling phase.
In the embodiment of the present application, the first preset range and the second preset range are both normal fluctuation ranges of the nitrogen oxygen value obtained according to an ideal model of the nitrogen oxygen value in the cooling stage. Since the first and second nitrogen and oxygen values are measured in the same cooling stage, there is a small error between the first and second nitrogen and oxygen values with respect to the preset nitrogen and oxygen values. Therefore, the second preset range is smaller than the first preset range. As an example, the first preset range may be 10% of the preset nitrogen oxygen value; the second predetermined range may be 3% of the predetermined nitrogen oxygen value.
In the embodiment of the application, when the difference value between the first nitrogen oxygen value and the preset nitrogen oxygen value exceeds the first preset range, and the difference value between the second nitrogen oxygen value and the preset nitrogen oxygen value exceeds the first preset range, the fault of the downstream nitrogen oxygen sensor is determined. It is appreciated that in the embodiments of the subject application, a difference between the first value of NOx and the predetermined value of NOx exceeding the first predetermined range indicates a malfunction of the upstream NOx sensor. At this moment, whether the downstream nitrogen oxygen sensor breaks down needs to be continuously monitored, and because the first nitrogen oxygen value measured by the upstream nitrogen oxygen sensor is inaccurate, the embodiment of the application adopts the preset nitrogen oxygen value to compare with the second nitrogen oxygen value measured by the downstream nitrogen oxygen sensor, so as to judge whether the downstream nitrogen oxygen sensor breaks down.
Considering that the nox value measured by the upstream nox sensor or the downstream nox sensor at one time may be greatly affected by the accidental factors and have a large error, in the embodiment of the present application, obtaining the first nox value by the upstream nox sensor may include: and taking the average value of the nitrogen and oxygen values measured by the upstream nitrogen and oxygen sensor within a preset time period as a first nitrogen and oxygen value. In the embodiment of the present application, obtaining the second nitrogen oxide value by the downstream nitrogen oxide sensor may include: and taking the average value of the nitrogen and oxygen values measured by the downstream nitrogen and oxygen sensor within a preset time period as a second nitrogen and oxygen value. As an example, the preset time period may be any one time period between 2 minutes and 5 minutes.
In the embodiment of the present application, in order to reduce the error reporting rate of the SCR that is low in the conversion efficiency of the nox, the determining the fault of the upstream nox sensor in the embodiment of the present application includes: and judging the fault of the upstream nitrogen-oxygen sensor, and inhibiting the diesel particle filtering system from diagnosing the conversion efficiency of nitrogen-oxygen compounds in the tail gas according to the nitrogen-oxygen value obtained by the upstream nitrogen-oxygen sensor. Accordingly, in the embodiment of the present application, determining a fault of the downstream nox sensor includes: and judging faults of the downstream nitrogen-oxygen sensor, and inhibiting the diesel particle filtering system from diagnosing the conversion efficiency of nitrogen-oxygen compounds in the tail gas according to the nitrogen-oxygen value obtained by the downstream nitrogen-oxygen sensor.
In the embodiment of the present application, as a possible implementation manner, in order to avoid adding an additional device and bringing additional cost, when it is determined that the upstream nox sensor is out of order, the warning of the failure of the upstream nox sensor may be implemented by an ECU (Electronic Control Unit) of the vehicle. Correspondingly, when the downstream nitrogen oxygen sensor is judged to be in fault, fault warning prompt of the downstream nitrogen oxygen sensor can be achieved through the ECU.
In summary, the embodiment of the present application provides a method and an apparatus for determining a fault of an upstream nox sensor, which compare a first nox value measured by the upstream nox sensor with a preset value, and determine whether a signal measured by the upstream nox sensor is accurate; and when the upstream nitrogen-oxygen sensor measures accurately, comparing the nitrogen-oxygen value measured by the upstream nitrogen-oxygen sensor with the nitrogen-oxygen value measured by the downstream sensor, and judging whether the signal measured by the downstream nitrogen-oxygen sensor is accurate or not. So, the scheme that this application embodiment provided can judge comparatively accurately whether the nitrogen oxygen value that upstream nitrogen oxygen sensor and low reaches nitrogen oxygen sensor measured is accurate to guarantee the accuracy of the nitrogen oxygen value that upstream nitrogen oxygen sensor and low reaches nitrogen oxygen sensor measured, and then guarantee urea (reductant) and add the accuracy.
According to the nitrogen oxygen sensor fault judgment method provided by the embodiment, the embodiment of the application also provides a nitrogen oxygen sensor fault judgment device. Referring to fig. 3, the schematic diagram of a structural diagram of a device for determining faults of a nitrogen oxygen sensor according to an embodiment of the present application is shown. As shown in fig. 3, the nitrogen oxide sensor fault determination device provided in the embodiment of the present application is applied to a diesel particulate filter system, and the device includes:
the control module 100 is configured to control the nox reducing agent to stop spraying when the diesel particulate filter system enters a cool down phase.
An obtaining module 200 is configured to obtain a first value of nitrogen and oxygen by an upstream nitrogen and oxygen sensor and a second value of nitrogen and oxygen by a downstream nitrogen and oxygen sensor during the cooling phase.
And the upstream judging module 300 is configured to compare the first nitrogen-oxygen value with a preset nitrogen-oxygen value, and judge whether the upstream nitrogen-oxygen sensor fails.
And the downstream judging module 400 is configured to compare the first nitrogen-oxygen value with a preset nitrogen-oxygen value, and compare the first nitrogen-oxygen value with the second nitrogen-oxygen value, so as to judge whether the downstream nitrogen-oxygen sensor fails.
In the embodiment of the application, the preset nitrogen and oxygen values are obtained according to an ideal nitrogen and oxygen value model of the cooling stage.
In this embodiment, as a possible implementation manner, the upstream determining module is specifically configured to: when the difference value between the first nitrogen oxygen value and the preset nitrogen oxygen value exceeds a first preset range, judging that the upstream nitrogen oxygen sensor has a fault; the first predetermined range is obtained from an ideal model of the nitrogen oxygen value during the cooling phase.
In this embodiment, as a possible implementation manner, the downstream determining module is specifically configured to: when the difference value between the first nitrogen oxygen value and the preset nitrogen oxygen value is within a first preset range and the difference value between the first nitrogen oxygen value and the second nitrogen oxygen value exceeds a second preset range, judging that the downstream nitrogen oxygen sensor has a fault; the second preset range is smaller than the first preset range; the second predetermined range is obtained from an ideal model of the nitrogen oxygen value during the cooling phase.
In this embodiment, as a possible implementation manner, the upstream determining module is specifically configured to: and when the difference value between the first nitrogen oxygen value and the preset nitrogen oxygen value exceeds a first preset range, judging that the upstream nitrogen oxygen sensor has a fault, and inhibiting the diesel particle filtering system from diagnosing the conversion efficiency of nitrogen oxides in the tail gas according to the nitrogen oxygen value obtained by the upstream nitrogen oxygen sensor. Correspondingly, the downstream judging module is specifically configured to: and when the difference value between the first nitrogen oxygen value and the preset nitrogen oxygen value is within a first preset range and the difference value between the first nitrogen oxygen value and the second nitrogen oxygen value exceeds a second preset range, judging that the downstream nitrogen oxygen sensor has a fault, and inhibiting the diesel particle filtering system from diagnosing the conversion efficiency of nitrogen oxides in the tail gas according to the nitrogen oxygen value obtained by the downstream nitrogen oxygen sensor.
In summary, the embodiment of the present application provides a method and an apparatus for determining faults of a nox sensor, where the apparatus can determine whether a fault occurs in an upstream nox sensor and a downstream nox sensor more accurately, thereby ensuring accuracy of nox values measured by the upstream nox sensor and the downstream nox sensor, and further ensuring accuracy of addition of a reducing agent (urea).
According to the nitrogen oxygen sensor fault judgment method and the nitrogen oxygen sensor fault judgment device provided by the embodiment, the embodiment of the application further provides a diesel particle filtering system. The diesel particulate filtering system provided by the embodiment of the application comprises the nitrogen oxide sensor fault judgment device, the upstream nitrogen oxide sensor and the downstream nitrogen oxide sensor. Wherein, the upstream nitrogen oxygen sensor and the downstream nitrogen oxygen sensor are respectively connected with the nitrogen oxygen sensor fault judgment device.
As can be seen from the above description of the embodiments, those skilled in the art can clearly understand that all or part of the steps in the above embodiment methods can be implemented by software plus a necessary general hardware platform. Based on such understanding, the technical solution of the present application may be essentially or partially implemented in the form of a software product, which may be stored in a storage medium, such as a ROM/RAM, a magnetic disk, an optical disk, etc., and includes several instructions for enabling a computer device (which may be a personal computer, a server, or a network communication device such as a media gateway, etc.) to execute the method according to the embodiments or some parts of the embodiments of the present application.
It should be noted that, in the present specification, 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. The method disclosed by the embodiment corresponds to the system disclosed by the embodiment, so that the description is simple, and the relevant points can be referred to the system part for description.
It should also be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
The foregoing description of the disclosed embodiments will enable those skilled in the art to make or use the invention in various modifications to these embodiments, which will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (11)
1. A method for judging faults of a nitrogen-oxygen sensor is applied to a diesel particle filtering system, and comprises the following steps:
when the diesel particulate filter system enters a cooling stage, controlling the nitrogen oxide reducing agent to stop spraying;
during the cooling phase, obtaining a first nitrogen and oxygen value through an upstream nitrogen and oxygen sensor and obtaining a second nitrogen and oxygen value through a downstream nitrogen and oxygen sensor;
comparing the first nitrogen and oxygen value with a preset nitrogen and oxygen value, and judging whether the upstream nitrogen and oxygen sensor fails;
comparing the first nitrogen oxygen value with the preset nitrogen oxygen value, and comparing the first nitrogen oxygen value with the second nitrogen oxygen value to judge whether the downstream nitrogen oxygen sensor has faults or not; and the preset nitrogen and oxygen value is obtained according to the ideal model of the nitrogen and oxygen value in the cooling stage.
2. The method of claim 1, wherein comparing the first value of nitrogen and oxygen to a preset value of nitrogen and oxygen to determine whether an upstream nitrogen and oxygen sensor is malfunctioning comprises:
when the difference value between the first nitrogen oxygen value and a preset nitrogen oxygen value exceeds a first preset range, judging that the upstream nitrogen oxygen sensor has a fault; the first preset range is obtained according to the ideal model of the nitrogen oxygen value of the cooling stage.
3. The method of claim 2, wherein comparing the first value of nitrogen and oxygen to the preset value of nitrogen and oxygen and comparing the first value of nitrogen and oxygen to the second value of nitrogen and oxygen to determine whether a downstream nitrogen and oxygen sensor is malfunctioning comprises:
when the difference value between the first nitrogen oxygen value and the preset nitrogen oxygen value is within the first preset range and the difference value between the first nitrogen oxygen value and the second nitrogen oxygen value exceeds a second preset range, judging that the downstream nitrogen oxygen sensor has a fault; the second preset range is smaller than the first preset range; the second preset range is obtained according to the ideal model of the nitrogen oxygen value of the cooling stage.
4. The method of claim 3, further comprising:
and when the difference value between the first nitrogen oxygen value and the preset nitrogen oxygen value exceeds the first preset range, and the difference value between the second nitrogen oxygen value and the preset nitrogen oxygen value exceeds the first preset range, judging that the downstream nitrogen oxygen sensor has a fault.
5. The method of claim 1, wherein the obtaining a first nitrogen to oxygen value by an upstream nitrogen to oxygen sensor comprises:
taking the average value of the nitrogen and oxygen values measured by the upstream nitrogen and oxygen sensor within a preset time as a first nitrogen and oxygen value;
the obtaining a second NOx value by a downstream NOx sensor includes:
and taking the average value of the nitrogen and oxygen values measured by the downstream nitrogen and oxygen sensor in the preset time period as a second nitrogen and oxygen value.
6. The method of claim 3, wherein the determining an upstream NOx sensor fault comprises:
judging faults of an upstream nitrogen-oxygen sensor, and inhibiting the diesel particle filtering system from diagnosing the conversion efficiency of nitrogen-oxygen compounds in tail gas according to a nitrogen-oxygen value obtained by the upstream nitrogen-oxygen sensor;
the method for judging the fault of the downstream nitrogen-oxygen sensor comprises the following steps:
and judging faults of the downstream nitrogen-oxygen sensor, and inhibiting the diesel particle filtering system from diagnosing the conversion efficiency of nitrogen-oxygen compounds in the tail gas according to the nitrogen-oxygen value obtained by the downstream nitrogen-oxygen sensor.
7. A nitrogen oxygen sensor fault diagnosis device, characterized in that, the device is applied to diesel particulate filter system, the device includes:
the control module is used for controlling the nitrogen oxide reducing agent to stop spraying when the diesel particulate filtering system enters a cooling stage;
an obtaining module, configured to obtain a first nitrogen-oxygen value by an upstream nitrogen-oxygen sensor and a second nitrogen-oxygen value by a downstream nitrogen-oxygen sensor during the cooling phase;
the upstream judgment module is used for comparing the first nitrogen and oxygen value with a preset nitrogen and oxygen value and judging whether the upstream nitrogen and oxygen sensor fails or not;
the downstream judging module is used for comparing the first nitrogen oxygen value with the preset nitrogen oxygen value, comparing the first nitrogen oxygen value with the second nitrogen oxygen value and judging whether the downstream nitrogen oxygen sensor has faults or not;
and the preset nitrogen and oxygen value is obtained according to the ideal model of the nitrogen and oxygen value in the cooling stage.
8. The apparatus according to claim 7, wherein the upstream determining module is specifically configured to:
when the difference value between the first nitrogen oxygen value and a preset nitrogen oxygen value exceeds a first preset range, judging that the upstream nitrogen oxygen sensor has a fault; the first preset range is obtained according to the ideal model of the nitrogen oxygen value of the cooling stage.
9. The apparatus of claim 8, wherein the downstream determining module is specifically configured to:
when the difference value between the first nitrogen oxygen value and the preset nitrogen oxygen value is within the first preset range and the difference value between the first nitrogen oxygen value and the second nitrogen oxygen value exceeds a second preset range, judging that the downstream nitrogen oxygen sensor has a fault; the second preset range is smaller than the first preset range; the second preset range is obtained according to the ideal model of the nitrogen oxygen value of the cooling stage.
10. The apparatus according to claim 9, wherein the upstream determining module is specifically configured to:
when the difference value between the first nitrogen oxygen value and a preset nitrogen oxygen value exceeds a first preset range, judging that the upstream nitrogen oxygen sensor has a fault, and inhibiting the diesel particle filtering system from diagnosing the conversion efficiency of nitrogen oxides in tail gas according to the nitrogen oxygen value obtained by the upstream nitrogen oxygen sensor;
the downstream judgment module is specifically configured to:
and when the difference value of the first nitrogen oxygen value and the preset nitrogen oxygen value is in the first preset range and the difference value of the first nitrogen oxygen value and the second nitrogen oxygen value exceeds the second preset range, judging that the downstream nitrogen oxygen sensor has a fault, and inhibiting the diesel particle filtering system from diagnosing the conversion efficiency of nitrogen oxides in the tail gas according to the nitrogen oxygen value obtained by the downstream nitrogen oxygen sensor.
11. A diesel particulate filtering system, characterized in that the system comprises the nitrogen oxide sensor malfunction determination device according to any one of claims 7 to 10, an upstream nitrogen oxide sensor, and a downstream nitrogen oxide sensor;
the upstream nitrogen-oxygen sensor and the downstream nitrogen-oxygen sensor are respectively connected with the nitrogen-oxygen sensor fault judgment device.
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