CN111042901B - Method and device for adjusting diagnosis times of nitrogen oxide conversion efficiency - Google Patents
Method and device for adjusting diagnosis times of nitrogen oxide conversion efficiency Download PDFInfo
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- CN111042901B CN111042901B CN201911415689.3A CN201911415689A CN111042901B CN 111042901 B CN111042901 B CN 111042901B CN 201911415689 A CN201911415689 A CN 201911415689A CN 111042901 B CN111042901 B CN 111042901B
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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
- 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
- F01N2900/1621—Catalyst conversion efficiency
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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
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
- Y02A50/20—Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
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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
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Abstract
The embodiment of the invention discloses a method for adjusting the diagnosis times of the conversion efficiency of oxynitrideA method and apparatus, the method comprising: detecting whether the vehicle runs under a preset working condition or not; calculating NOx (nitrogen oxide) NO when the vehicle runs under the preset working conditionxThe conversion efficiency of (a); according to said NOxConversion efficiency and NOxObtaining NO by correlation of correction times for conversion efficiency diagnosisxThe number of corrections for the conversion efficiency diagnosis; NO fixed to the vehicle according to the number of correctionsxThe number of conversion efficiency diagnoses is automatically adjusted. In the method for adjusting the diagnosis times provided by the application, NO can be generatedxThe number of conversion efficiency diagnostics is changed from a fixed value to a value that varies with the conversion efficiency, i.e. may be based on NO in the SCRxThe diagnosis times are automatically adjusted under the condition of conversion efficiency, so that the detection times of fault reporting of the SCR can be increased under the condition that the actual efficiency of the SCR is high, the fault reporting times are reduced under the condition that the actual efficiency of the SCR is low, the possibility of false reporting is reduced, and the reporting of real faults can be accelerated.
Description
Technical Field
The invention relates to the field of fault diagnosis, in particular to a method and a device for adjusting the diagnosis times of the conversion efficiency of oxynitride.
Background
With the increasing emission of motor vehicles, emission regulations for motor vehicle pollution are continuously upgraded, and besides the requirement that newly produced engines meet production certification, emission monitoring is also needed in the driving process, namely, On-Board Diagnostics (OBD). On-board diagnostics (OBD), an on-line monitoring system for controlling vehicle emissions, has now progressed to stage 2, requiring Selective Catalytic Reduction (SCR) diagnostics to progress from severe functional failures to emissions overproof due to reduced SCR efficiency.
Nitrogen oxides NO in SCR in motor vehiclesxThe diagnosis times of the conversion efficiency are fixed after the vehicle leaves the factory and are constant after the NO is treatedxWhen the number of diagnosis times of conversion efficiency is set, NO is ensuredxThe conversion efficiency diagnosis is not misdiagnosed, and the detection window is reduced, thereby causing the detection times of the Transient test Cycle (WHTC) of the engine emission verificationLess number, and thus to NOxWhen the conversion efficiency is diagnosed, the calibrated fault reporting times are less.
To reduce the detection window resulting in fixed NOxAlthough the diagnosis frequency of the conversion efficiency can reduce the false diagnosis alarm frequency of the SCR caused by low efficiency, the fault of the SCR with low efficiency cannot be normally detected because the WHTC detection frequency is less and the diagnosis frequency is fixed, thereby causing the emission standard exceeding caused by the reduction of the SCR efficiency.
Disclosure of Invention
In view of the above problems, the present application provides a method and an apparatus for adjusting the number of times of diagnosing the conversion efficiency of an oxynitride, which are used to solve the problem of misdiagnosis caused by a small number of times of diagnosing the SCR efficiency.
In a first aspect of the present application, there is provided a method for adjusting the number of times of diagnosing the conversion efficiency of nitrogen oxide, the method including:
detecting whether the vehicle runs under a preset working condition or not;
calculating NOx (nitrogen oxide) NO when the vehicle runs under the preset working conditionxThe conversion efficiency of (a);
according to said NOxConversion efficiency and NOxObtaining NO by correlation of correction times for conversion efficiency diagnosisxThe number of corrections for the conversion efficiency diagnosis;
NO fixed to the vehicle according to the number of correctionsxThe number of conversion efficiency diagnoses is automatically adjusted.
Optionally, the NO fixed to the vehicle according to the correction timesxThe number of conversion efficiency diagnoses is automatically adjusted, including:
immobilizing the vehicle with NO when the conversion efficiency is greater than an efficiency thresholdxAdding the number of conversion efficiency diagnoses to the number of corrections to obtain NOxA target number of diagnoses of conversion efficiency;
immobilizing the vehicle with NO when the conversion efficiency is less than an efficiency thresholdxSubtracting the correction times from the conversion efficiency diagnosis times to obtain NOxTarget number of diagnoses of conversion efficiency.
Optionally, the preset working condition includes:
the method comprises the following steps that one or more of the conditions of stable working conditions of an engine of the vehicle, the condition that the exhaust temperature of the engine of the vehicle meets the preset temperature value, the condition that the exhaust mass flow of the engine of the vehicle meets the preset flow value and the condition that the ammonia storage amount of the vehicle meets the preset ammonia storage amount value are adopted.
Optionally, when the vehicle runs under the preset working condition, calculating nitrogen oxide NOxThe conversion efficiency of (a), comprising:
when the vehicle runs under the preset working condition, and when the vehicle is in a power failure condition or the calculation of the conversion efficiency is not completed for one time, the NO calculated by the vehicle under the preset working condition for the last time is adoptedxThe conversion efficiency of (a).
Optionally, the method further includes:
when the vehicle runs under the preset working condition, calculating the service time of a Selective Catalytic Reduction (SCR) system;
according to said time of use and NOxObtaining NO by correlation of correction times for conversion efficiency diagnosisxThe number of corrections for the conversion efficiency diagnosis.
Optionally, the NO fixed to the vehicle according to the correction timesxThe number of conversion efficiency diagnoses is automatically adjusted, including:
immobilizing the vehicle with NO when the usage time is greater than a time thresholdxAdding the number of conversion efficiency diagnoses to the number of corrections to obtain NOxA target number of diagnoses of conversion efficiency;
immobilizing the vehicle with NO when the usage time is less than a time thresholdxSubtracting the correction times from the conversion efficiency diagnosis times to obtain NOxTarget number of diagnoses of conversion efficiency.
Optionally, the calculating the service time of the SCR system includes:
and when the SCR of the vehicle updates the component, clearing the timer and recalculating the service time of the SCR.
In a second aspect of the present application, there is provided an apparatus for adjusting the number of times of diagnosing a conversion efficiency of nitrogen oxide, the apparatus including:
the device comprises a detection unit, a calculation unit, an acquisition unit and a correction unit;
the detection unit is used for detecting whether the vehicle runs under a preset working condition or not;
the calculation unit is used for calculating the NOx NO when the vehicle runs under the preset working conditionxThe conversion efficiency of (a);
the acquisition unit is used for acquiring the NOxConversion efficiency and NOxObtaining NO by correlation of correction times for conversion efficiency diagnosisxThe number of corrections for the conversion efficiency diagnosis;
the correcting unit is used for fixing NO for the vehicle according to the correcting timesxThe number of conversion efficiency diagnoses is automatically adjusted.
Optionally, the modifying unit includes:
an increase unit and a decrease unit;
the increasing unit is used for fixing NO of the vehicle when the conversion efficiency is larger than an efficiency threshold valuexAdding the number of conversion efficiency diagnoses to the number of corrections to obtain NOxA target number of diagnoses of conversion efficiency;
the reduction unit is used for fixing NO of the vehicle when the conversion efficiency is smaller than an efficiency threshold valuexSubtracting the correction times from the conversion efficiency diagnosis times to obtain NOxTarget number of diagnoses of conversion efficiency.
Optionally, the apparatus further comprises:
the time calculating unit and the time acquiring unit;
the time calculation unit is used for calculating the service time of the selective catalytic reduction system SCR when the vehicle runs under the preset working condition;
the timeAn acquisition unit for acquiring the usage time and NOxObtaining NO by correlation of correction times for conversion efficiency diagnosisxThe number of corrections for the conversion efficiency diagnosis.
Compared with the prior art, the technical scheme of the application has the advantages that:
in the technical method provided by the application, whether a vehicle runs under a preset working condition or not is detected, and then when the vehicle runs under the preset working condition, nitrogen oxide NO is calculatedxAccording to the conversion efficiency of said NOxConversion efficiency and NOxObtaining NO by correlation of correction times for conversion efficiency diagnosisxNumber of corrections for conversion efficiency diagnostics, and finally NO fixed for said vehicle according to said number of correctionsxThe number of conversion efficiency diagnoses is automatically adjusted. In the method for adjusting the number of times of diagnosing the conversion efficiency of the oxynitride, NO is calculated under a preset working conditionxThe conversion efficiency of the SCR is closer to the real conversion efficiency of the SCR, and NO is automatically adjusted according to the correction times obtained by the closer conversion efficiency to the real conversion efficiencyxThe number of conversion efficiency diagnoses is such that NO isxThe diagnosis times of the conversion efficiency are changed from a fixed value to a value changing along with the conversion efficiency, namely NO in SCR under the condition of a preset working conditionxThe diagnosis times are automatically adjusted under the condition of conversion efficiency, so that the detection times of fault reporting of the SCR can be increased under the condition that the actual efficiency of the SCR is high, the fault reporting times are reduced under the condition that the actual efficiency of the SCR is low, the possibility of false reporting is reduced, and the reporting of real faults can be accelerated.
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 described below, it is obvious that the drawings in the following description are only some embodiments described in the present application, and other drawings can be obtained by those skilled in the art without creative efforts.
FIG. 1 is a flow chart of a method for adjusting the number of diagnoses of NOx conversion efficiency provided herein;
FIG. 2 is a flow chart illustrating a method for adjusting the number of diagnoses of NOx conversion efficiency provided herein;
fig. 3 is a schematic diagram of an apparatus for adjusting the number of times of diagnosing the conversion efficiency of an oxynitride provided by the present application.
Detailed Description
In order to make the technical solutions of the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Referring to FIG. 1, FIG. 1 is a NO provided hereinxA flow chart of a method for adjusting the number of conversion efficiency diagnoses, the method may include the following steps 101-104.
Step 101: whether the vehicle runs under the preset working condition is detected.
SCR will convert NO in tail gas with a certain conversion efficiencyxConversion to other molecules to avoid atmospheric pollution. In real life, many conditions can cause NO in the SCRxThe conversion efficiency is lowered, for example, in the case of failure or deterioration in performance due to wear or damage. In addition, NO is caused in the case of normal SCRxReduced conversion efficiency, e.g. by a change in the nature of the exhaust stream of the chemical reaction taking place to cause NOxThe reduction of conversion efficiency, exhaust gas temperature, ammonia storage amount, etc. cause NOxThe conversion efficiency decreases. So in calculating NOxWhen the conversion efficiency is obtained, it should be ensured that the calculated efficiency is obtained by calculation under the same working condition, that is, the conversion efficiency is comparable to the conversion efficiency obtained by calculation under the preset working condition.
It should be noted that the preset working condition may be that the engine working condition of the vehicle is stable, where the stable working condition of the engine means that various parameters of the engine are basically unchanged, such as the parameters of the rotation speed, the oil amount, the torque, and the like are basically unchanged or slightly changed.
It should be noted that the preset working condition may be that the exhaust temperature of the engine of the vehicle meets a preset temperature value, and the preset temperature value may be adjusted according to an actual condition. The efficiency obtained by calculating the exhaust temperature of the engine at about 300 ℃ is found to be more suitable for the actual situation according to a plurality of experimental data, and the typical characteristics of urban working conditions are low speed, repeated parking and starting, and relatively low load of the vehicle. Low speed, low load urban conditions typically result in exhaust temperatures below 300 ℃. Under the working condition, the working efficiency of SCR is low due to the reduction of the urea injection quantity and the low activity of the catalyst, and in order to avoid the situation, the exhaust temperature is suitably controlled to be about 300 ℃.
It should be noted that the preset working condition may be that the mass flow of the engine exhaust of the vehicle meets a preset flow value, and the preset flow value may be adjusted according to an actual condition. Different models and applications will vary in choice, and a moderate exhaust mass flow rate will generally be selected. The basis for the selection is to try to make the exhaust gas mass flow smaller in order to ensure that the exhaust temperature meets the requirements, since too large an exhaust gas mass flow would result in NOxThe residence reaction time in the SCR is shortened, and the conversion capability of the SCR is weakened; when the exhaust mass flow is too small, the exhaust temperature is generally lower.
It should be noted that the preset working condition may be that the ammonia storage amount of the vehicle meets a preset ammonia storage amount value, and the preset ammonia storage amount value may be adjusted according to an actual situation. The ammonia storage is recommended to be carried out under the working condition of about 50 percent, certain ammonia storage can be ensured in the SCR under the condition, and ammonia gas leakage caused by excessive ammonia storage can be avoided.
It should be noted that the preset operating condition may be one or more of the above four conditions, and particularly, the preset operating condition is a severe operating condition when the four conditions are all satisfied, and the calculated NO is obtainedxConversion efficiency closest to the true conversion efficiency of the SCRAnd (4) rate.
Step 102: calculating NOx (nitrogen oxide) NO when the vehicle runs under the preset working conditionxThe conversion efficiency of (a).
NO under the condition of preset working conditionxConversion efficiency can be determined from the converted NOxValue and original NOxThe ratio of (a) to (b) is calculated.
Step 103: according to said NOxConversion efficiency and NOxObtaining NO by correlation of correction times for conversion efficiency diagnosisxThe number of corrections for the conversion efficiency diagnosis.
It should be noted that, after the operating condition of the vehicle is adjusted to the preset condition, since the condition of the preset condition is severer than the conventional condition, the efficiency result can be calculated for 1 time through a plurality of driving cycles, so that the correction times corresponding to the efficiency can be obtained by querying the CUR table.
Step 104: NO fixed to the vehicle according to the number of correctionsxThe number of conversion efficiency diagnoses is automatically adjusted.
By the obtained number of corrections, NO can be adjustedxThe number of conversion efficiency diagnoses. NO of vehicle obtained by correction at this timexThe conversion efficiency diagnosis times are not fixed and are changed along with the change of the SCR efficiency, so that the requirement that the WHTC tests the fault with low efficiency can be met, and the problem of misinformation caused by the low SCR efficiency in practical application can be solved.
In one possible embodiment, the specific automatic adjustment may be to fix the NO of the vehicle when the conversion efficiency is greater than an efficiency thresholdxAdding the number of conversion efficiency diagnoses to the number of corrections to obtain NOxA target number of diagnoses of conversion efficiency; immobilizing the vehicle with NO when the conversion efficiency is less than an efficiency thresholdxSubtracting the correction times from the conversion efficiency diagnosis times to obtain NOxTarget number of diagnoses of conversion efficiency. For example, if the preset efficiency threshold is 0.7, when the calculated conversion efficiency is 0.8, 0.8 is greater than 0.7, which is the case when the conversion efficiency is greater than the efficiency threshold, the previous steps are performedThe number of corrections corresponding to the conversion efficiency of 0.8 obtained is 5, and NO can be fixed in a vehicle fixed on the vehiclexThe number of conversion efficiency diagnoses is increased by 5 times on the basis of 4 times, namely NOxThe target number of diagnoses for transformation efficiency was 9. When the calculated conversion efficiency is 0.2, 0.2 is less than 0.7, and the conversion efficiency is lower than the efficiency threshold value, the correction times corresponding to the conversion efficiency of 0.2 obtained through the previous steps are 2 times, and NO can be fixed on a vehicle fixed by the vehiclexThe number of conversion efficiency diagnoses was reduced by 2 times on the basis of 4 times, i.e., NOxThe target number of diagnoses for transformation efficiency was 2.
In one possible embodiment, sometimes according to the NOxConversion efficiency and NOxObtaining NO by correlation of correction times for conversion efficiency diagnosisxThe number of corrections to the conversion efficiency diagnostic may be negative when the NO is fixed for the vehiclexAdding the number of conversion efficiency diagnoses to the number of corrections to obtain NOxThe target number of times of diagnosis of the conversion efficiency is sufficient, and it is no longer necessary to judge the relationship between the conversion efficiency and the efficiency threshold.
It should be noted that when the vehicle is in a power failure condition or the conversion efficiency calculation is not completed for one time, the power-off storage is needed, that is, the NO calculated in the last driving cycle is adoptedxAs a result of conversion efficiency ofxAnd (6) diagnosing the conversion efficiency. The NO can then be reconciled until a new efficiency result is calculatedxThe number of conversion efficiency diagnoses is adjusted.
In the technical method provided by the application, whether a vehicle runs under a preset working condition or not is detected, and then when the vehicle runs under the preset working condition, nitrogen oxide NO is calculatedxAccording to the conversion efficiency of said NOxConversion efficiency and NOxObtaining NO by correlation of correction times for conversion efficiency diagnosisxNumber of corrections for conversion efficiency diagnostics, and finally NO fixed for said vehicle according to said number of correctionsxThe number of conversion efficiency diagnoses is automatically adjusted. In the method for adjusting the number of times of diagnosis of the conversion efficiency of nitrogen oxide compounds provided by the present application, the number is presetNO calculated under operating conditionsxThe conversion efficiency of the SCR is closer to the real conversion efficiency of the SCR, and NO is automatically adjusted according to the correction times obtained by the closer conversion efficiency to the real conversion efficiencyxThe number of conversion efficiency diagnoses is such that NO isxThe number of conversion efficiency diagnostics is changed from a fixed value to a value that varies with the conversion efficiency, i.e. may be based on NO in the SCRxThe diagnosis times are automatically adjusted under the condition of conversion efficiency, so that the detection times of fault reporting of the SCR can be increased under the condition that the actual efficiency of the SCR is high, the fault reporting times are reduced under the condition that the actual efficiency of the SCR is low, the possibility of false reporting is reduced, and the reporting of real faults can be accelerated.
Further, the vehicle may be fixed with NO when the conversion efficiency is greater than an efficiency thresholdxAdding the number of conversion efficiency diagnoses to the number of corrections; immobilizing the vehicle with NO when the conversion efficiency is less than an efficiency thresholdxThe number of conversion efficiency diagnoses is subtracted from the number of corrections. By NO in SCR according to the abovexThe change in conversion efficiency increases or decreases the fixed number of diagnoses, which may be more realistic.
The above examples are based on NO in SCRxThe fixed diagnosis times are adjusted according to the conversion efficiency, and may also be adjusted according to the usage time of the SCR, so as to make the technical solution provided by the embodiment of the present invention clearer, the NO provided by the embodiment of the present invention is provided as an example with reference to fig. 2xA self-tuning method of the number of conversion efficiency diagnoses is described. Reference to FIG. 2 is a reference to another NO provided hereinxA flow chart of a self-adapting method of the number of conversion efficiency diagnoses, which method may comprise the following steps 201 and 206.
The steps 201-203 can refer to the steps 101-103, which are not described herein again.
In regulating NOxWhen the number of times of the conversion efficiency diagnosis is counted, the use time of the SCR can be considered, and the specific idea is that the longer the use time of the SCR is, the NO is treated by the SCRxThe lower the conversion efficiency, the lower the number of diagnoses can be made, and the better the performance of the SCR when it is used for a shorter period of timeTo NOxThe transformation efficiency will be slightly higher, and the number of diagnosis times can be increased appropriately, and the specific steps are as follows:
step 204: and when the vehicle runs under the preset working condition, calculating the service time of the selective catalytic reduction system SCR.
A timer may be used to record the time of use of the SCR.
Step 205: according to said time of use and NOxObtaining NO by correlation of correction times for conversion efficiency diagnosisxThe number of corrections for the conversion efficiency diagnosis.
Can be obtained by inquiring the service time of SCR and NOxThe correction times are obtained from a correspondence table of the correction times for the conversion efficiency diagnosis.
Step 206: fixing NO of the vehicle according to the correction times obtained by the conversion efficiency and the service timexThe number of conversion efficiency diagnoses is automatically adjusted.
Adjusting NO by correction times based on the conversion efficiency and the usage timexThe number of conversion efficiency diagnoses. NO of vehicle obtained at this timexThe conversion efficiency diagnosis times are not fixed any more, but change along with the change of the conversion efficiency and the SCR service time, so that the requirement of a WHTC test on reporting a fault with low efficiency can be met, and the problem of misinformation caused by low SCR efficiency in practical application can be reduced.
In one possible embodiment, the vehicle is set to NO when the period of use is greater than a time thresholdxAdding the number of conversion efficiency diagnoses to the number of corrections to obtain NOxA target number of diagnoses of conversion efficiency; immobilizing the vehicle with NO when the usage time is less than a time thresholdxSubtracting the correction times from the conversion efficiency diagnosis times to obtain NOxTarget number of diagnoses of conversion efficiency. In this embodiment, the time threshold is not specifically limited, and may be set according to different vehicle types or different materials of the SCR.
In one possible embodiment, sometimes according to the time of use and NOxObtaining NO by correlation of correction times for conversion efficiency diagnosisxThe number of corrections to the conversion efficiency diagnostic may be negative when the NO is fixed for the vehiclexAdding the number of conversion efficiency diagnoses to the number of corrections to obtain NOxThe target number of times of diagnosis of the conversion efficiency is sufficient, and it is no longer necessary to judge the relationship between the conversion efficiency and the efficiency threshold.
In the embodiment of the present application, the use time of SCR can be used to assist in adjusting NOxThe target number of diagnoses of transformation efficiency, specifically: auxiliary adjustment of NO based on SCR agexThe number of conversion efficiency diagnoses is such that NO isxThe number of diagnoses made for the conversion efficiency is changed from a fixed value to a value that varies with the conversion efficiency, i.e. can be based on NO in the SCRxThe diagnosis times are automatically adjusted under the condition of conversion efficiency, and the problem that the calibrated fault reporting times are small can be solved under the condition that a detection window is not required to be reduced.
Further, the vehicle may be immobilized NO when the usage time is greater than a time thresholdxAdding the number of conversion efficiency diagnoses to the number of corrections to obtain NOxA target number of diagnoses of conversion efficiency; immobilizing the vehicle with NO when the usage time is less than a time thresholdxSubtracting the correction times from the conversion efficiency diagnosis times to obtain NOxThe target diagnosis times of the conversion efficiency can better meet the actual situation.
The embodiment of the invention provides NOxBesides the self-regulating method of conversion efficiency diagnosis times, it also provides a NOxThe self-adjusting method device for the conversion efficiency diagnosis times, as shown in fig. 3, comprises:
a detection unit 310, a calculation unit 320, an acquisition unit 330 and a correction unit 340; wherein:
the detection unit 310 may be configured to detect whether the vehicle is operating under a preset operating condition;
get the noteElement 330 may be used according to the NOxConversion efficiency and NOxObtaining NO by correlation of correction times for conversion efficiency diagnosisxThe number of corrections for the conversion efficiency diagnosis;
the correction unit 340 may be adapted to fix the NO for said vehicle based on said number of correctionsxThe number of conversion efficiency diagnoses is automatically adjusted.
In a possible implementation, the modification unit 340 may further include an increase unit and a decrease unit, specifically: the increasing unit may be adapted to fix the NO for the vehicle when the conversion efficiency is larger than an efficiency thresholdxAdding the number of conversion efficiency diagnoses to the number of corrections to obtain NOxA target number of diagnoses of conversion efficiency; the reducing unit may be adapted to fix the NO for the vehicle when the conversion efficiency is less than an efficiency thresholdxSubtracting the correction times from the conversion efficiency diagnosis times to obtain NOxTarget number of diagnoses of conversion efficiency.
In a possible embodiment, when the usage time of the SCR is used to assist in correcting the number of diagnoses, the apparatus may further include: time calculating unit and time acquisition unit, wherein:
the time calculation unit can be used for calculating the service time of the selective catalytic reduction system SCR when the vehicle runs under the preset working condition;
the time acquisition unit may be configured to obtain the usage time and NOxObtaining NO by correlation of correction times for conversion efficiency diagnosisxThe number of corrections for the conversion efficiency diagnosis.
The embodiments in the present specification are described in a progressive manner, and the same and similar parts among the embodiments are referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, for the apparatus embodiment, since it is substantially similar to the method embodiment, it is relatively simple to describe, and reference may be made to some descriptions of the method embodiment for relevant points. The above-described apparatus embodiments are merely illustrative, and the units and modules described as separate components may or may not be physically separate. In addition, some or all of the units and modules may be selected according to actual needs to achieve the purpose of the solution of the embodiment. One of ordinary skill in the art can understand and implement it without inventive effort.
The foregoing is directed to embodiments of the present invention, and it is understood that various modifications and improvements can be made by those skilled in the art without departing from the spirit of the invention.
Claims (8)
1. A method for adjusting the number of diagnoses for nitrogen oxide conversion efficiency, the method comprising:
detecting whether the vehicle runs under a preset working condition or not;
calculating NOx (nitrogen oxide) NO when the vehicle runs under the preset working conditionxThe conversion efficiency of (a);
according to said NOxConversion efficiency and NOxObtaining NO by correlation of correction times for conversion efficiency diagnosisxThe number of corrections for the conversion efficiency diagnosis;
NO fixed to the vehicle according to the number of correctionsxThe number of conversion efficiency diagnoses is automatically adjusted, including:
immobilizing the vehicle with NO when the conversion efficiency is greater than an efficiency thresholdxAdding the number of conversion efficiency diagnoses to the number of corrections to obtain NOxA target number of diagnoses of conversion efficiency;
immobilizing the vehicle with NO when the conversion efficiency is less than an efficiency thresholdxSubtracting the correction times from the conversion efficiency diagnosis times to obtain NOxTarget number of diagnoses of conversion efficiency.
2. The method of claim 1, wherein the predetermined operating conditions comprise:
the method comprises the following steps that one or more of the conditions of stable working conditions of an engine of the vehicle, the condition that the exhaust temperature of the engine of the vehicle meets the preset temperature value, the condition that the exhaust mass flow of the engine of the vehicle meets the preset flow value and the condition that the ammonia storage amount of the vehicle meets the preset ammonia storage amount value are adopted.
3. The method of claim 1, wherein the NOx NO is calculated when the vehicle is operating at the predetermined operating conditionxThe conversion efficiency of (a), comprising:
when the vehicle runs under the preset working condition, and when the vehicle is in a power failure condition or the calculation of the conversion efficiency is not completed for one time, the NO calculated by the vehicle under the preset working condition for the last time is adoptedxThe conversion efficiency of (a).
4. The method of claim 1, further comprising:
when the vehicle runs under the preset working condition, calculating the service time of a Selective Catalytic Reduction (SCR) system;
according to said time of use and NOxObtaining NO by correlation of correction times for conversion efficiency diagnosisxThe number of corrections for the conversion efficiency diagnosis.
5. The method of claim 4, wherein the NO fixed for the vehicle is based on the number of correctionsxThe number of conversion efficiency diagnoses is automatically adjusted, including:
immobilizing the vehicle with NO when the usage time is greater than a time thresholdxAdding the number of conversion efficiency diagnoses to the number of corrections to obtain NOxA target number of diagnoses of conversion efficiency;
immobilizing the vehicle with NO when the usage time is less than a time thresholdxSubtracting the correction times from the conversion efficiency diagnosis times to obtain NOxTarget number of diagnoses of conversion efficiency.
6. The method of claim 4, wherein calculating the age of the SCR system comprises:
and when the SCR of the vehicle updates the component, clearing the timer and recalculating the service time of the SCR.
7. An apparatus for adjusting the number of times of diagnosis of nitrogen oxide conversion efficiency, said apparatus comprising:
the device comprises a detection unit, a calculation unit, an acquisition unit and a correction unit;
the detection unit is used for detecting whether the vehicle runs under a preset working condition or not;
the calculation unit is used for calculating the NOx NO when the vehicle runs under the preset working conditionxThe conversion efficiency of (a);
the acquisition unit is used for acquiring the NOxConversion efficiency and NOxObtaining NO by correlation of correction times for conversion efficiency diagnosisxThe number of corrections for the conversion efficiency diagnosis; the correcting unit is used for fixing NO for the vehicle according to the correcting timesxThe diagnosis times of the conversion efficiency are automatically adjusted;
the correction unit includes: an increase unit and a decrease unit;
the increasing unit is used for fixing NO of the vehicle when the conversion efficiency is larger than an efficiency threshold valuexAdding the number of conversion efficiency diagnoses to the number of corrections to obtain NOxA target number of diagnoses of conversion efficiency;
the reduction unit is used for fixing NO of the vehicle when the conversion efficiency is smaller than an efficiency threshold valuexSubtracting the correction times from the conversion efficiency diagnosis times to obtain NOxTarget number of diagnoses of conversion efficiency.
8. The apparatus of claim 7, further comprising:
the time calculating unit and the time acquiring unit;
the time calculation unit is used for calculating the service time of the selective catalytic reduction system SCR when the vehicle runs under the preset working condition;
the time acquisition unit is used for acquiring the time and NO according to the use timexObtaining NO by correlation of correction times for conversion efficiency diagnosisxThe number of corrections for the conversion efficiency diagnosis.
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