CN113530656B - DPF fault monitoring method and device - Google Patents
DPF fault monitoring method and device Download PDFInfo
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- CN113530656B CN113530656B CN202111042027.3A CN202111042027A CN113530656B CN 113530656 B CN113530656 B CN 113530656B CN 202111042027 A CN202111042027 A CN 202111042027A CN 113530656 B CN113530656 B CN 113530656B
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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
- 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
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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
- 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
- F01N11/005—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 the temperature or pressure being estimated, e.g. by means of a theoretical model
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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
- F01N2550/00—Monitoring or diagnosing the deterioration of exhaust systems
- F01N2550/04—Filtering activity of particulate filters
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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 invention provides a fault monitoring method and a device of a DPF (diesel particulate filter), wherein the method comprises the following steps: acquiring the state parameters of the DPF at the current moment; judging whether the state parameters meet monitoring enabling conditions or not; if so, obtaining a current pressure difference estimation value of the DPF based on the first initial pressure difference value and the second initial pressure difference value; the first initial differential pressure value is obtained by calculation according to a differential pressure model, and the second initial differential pressure value is obtained by collection according to a differential pressure collector arranged on the DPF; comparing the pressure difference estimation value with the corrected pressure difference lower limit value; if the pressure difference estimation value is smaller than the pressure difference lower limit value, determining that the DPF is in an initial abnormal state, and recording the duration of the DPF in the initial abnormal state; if the duration is greater than a preset duration threshold, updating the abnormal times; and if the updated abnormal times are larger than a preset time threshold, determining that the DPF is in fault. By applying the method provided by the invention, the robustness of DPF monitoring can be improved.
Description
Technical Field
The invention relates to the technical field of exhaust emission post-treatment of internal combustion engines, in particular to a fault monitoring method and device of a DPF (diesel particulate filter).
Background
Particulate matter is one of the main pollutants in the exhaust emission of diesel engines, and the most effective after-treatment device for reducing the particulate matter emission of diesel engines at present is a wall-flow particulate matter trap (DPF). When the trapped particulate matter of the DPF reaches a certain limit value, measures are taken to clean the particulate matter, namely DPF regeneration. DPF is probably because of the excessive temperature burns out at regeneration process to lead to DPF filtration efficiency to descend, consequently, in order to ensure DPF's normal work, need monitor DPF.
In the prior art, the DPF fault is reported when the detected differential pressure value acquired by the sensor is smaller than the lower differential pressure limit value by comparing the differential pressure value acquired by the DPF differential pressure sensor with the lower differential pressure limit value, however, the precision of the existing DPF differential pressure sensor is about 5hPa, the differential pressure range in normal use of the DPF is 0-60 hPa, and the deviation of a normal part and a cracking part of the DPF is within 10hPa in a general application working condition, so the robustness of the filtering efficiency monitoring strategy of the DPF is greatly reduced due to the low precision of the DPF differential pressure sensor.
Disclosure of Invention
The invention aims to provide a DPF fault monitoring method, which can improve the robustness of DPF monitoring.
The invention also provides a DPF fault monitoring device, which is used for ensuring the realization and application of the method in practice.
A method of fault monitoring a DPF, comprising:
acquiring the current state parameters of the DPF of the diesel particulate filter;
judging whether the state parameters meet preset monitoring enabling conditions or not;
under the condition that the state parameters meet the enabling conditions, obtaining a differential pressure estimation value of the DPF at the current moment based on a first initial differential pressure value and a second initial differential pressure value; the first initial differential pressure value is obtained by calculation according to a preset differential pressure model, and the second initial differential pressure value is obtained by collection based on a differential pressure collector which is arranged on the DPF in advance;
acquiring a current corrected lower limit value of the differential pressure, and comparing the estimated value of the differential pressure with the lower limit value of the differential pressure;
if the estimated pressure difference value is smaller than the lower pressure difference limit value, determining that the DPF is in an initial abnormal state, and recording the duration of the DPF in the initial abnormal state;
updating the abnormal times of the DPF under the condition that the duration of the DPF in the initial abnormal state is greater than a preset duration threshold;
and if the updated abnormal frequency of the DPF is greater than a preset frequency threshold value, determining that the DPF is in fault.
Optionally, the obtaining an estimated value of the pressure difference of the DPF at the current time based on the first initial pressure difference value and the second initial pressure difference value includes:
and inputting the first initial differential pressure value and the second initial differential pressure value into a preset Kalman filter for calculation to obtain a differential pressure estimation value of the DPF at the current moment.
Optionally, the above method, where the first initial differential pressure value and the second initial differential pressure value are input to a preset kalman filter to be calculated, so as to obtain the differential pressure estimation value of the DPF at the current time, includes:
determining the deviation of the acquisition value at the current moment based on the first initial differential pressure value and the second initial differential pressure value;
obtaining a current Kalman gain according to the acquired value deviation of the current moment and the estimated value deviation of the previous moment of the current moment;
and calculating to obtain the differential pressure estimation value of the DPF at the current moment based on the differential pressure estimation value of the previous moment, the Kalman gain and the second initial differential pressure value.
Optionally, the method for determining whether the state parameter meets a preset monitoring enabling condition includes:
judging whether the state of the differential pressure sensor in the state parameters is a prepared measurement state or not;
judging whether the engine rotating speed in the state parameters is in a preset rotating speed range or not;
judging whether the fuel injection quantity in the state parameters is in a preset injection quantity range or not;
judging whether the average temperature of the DPF in the state parameters is in a preset temperature range or not;
judging whether the carbon loading capacity in the state parameters is in a preset carbon loading capacity range or not;
when the judgment results of the above judgments are all yes, determining that the state parameter meets the monitoring enabling condition;
and under the condition that any judgment result of the judgment is negative, determining that the state parameter does not meet the monitoring enabling condition.
The above method, optionally, the obtaining a current corrected lower limit value of the differential pressure includes:
inquiring a preset limit pressure difference table based on the volume flow and the average temperature of the exhaust gas of the DPF to obtain an initial pressure difference lower limit value;
determining a differential pressure limit correction factor for the initial differential pressure value based on the carbon loading of the DPF;
and correcting the initial pressure difference lower limit value based on the pressure difference limit value correction factor to obtain the current corrected pressure difference lower limit value.
The above method, optionally, further includes:
and if the updated abnormal frequency of the DPF is not greater than the frequency threshold value, returning to the step of obtaining the current state parameters of the DPF of the diesel particulate filter.
A fault monitoring device of a DPF, comprising:
the device comprises an acquisition unit, a control unit and a control unit, wherein the acquisition unit is used for acquiring the current state parameters of the DPF of the diesel particulate filter;
the judging unit is used for judging whether the state parameters meet the preset monitoring enabling conditions or not;
the execution unit is used for obtaining a differential pressure estimation value of the DPF at the current moment based on a first initial differential pressure value and a second initial differential pressure value under the condition that the state parameter meets the enabling condition; the first initial differential pressure value is obtained by calculation according to a preset differential pressure model, and the second initial differential pressure value is obtained by collection based on a differential pressure collector which is arranged on the DPF in advance;
the comparison unit is used for acquiring the current corrected pressure difference lower limit value and comparing the pressure difference estimation value with the pressure difference lower limit value;
the first determining unit is used for determining that the DPF is in an initial abnormal state if the estimated pressure difference value is smaller than the lower pressure difference limit value, and recording the duration of the DPF in the initial abnormal state;
the updating unit is used for updating the abnormal times of the DPF under the condition that the duration of the DPF in the initial abnormal state is greater than a preset duration threshold;
and the second determining unit is used for determining that the DPF is in failure if the updated abnormal frequency of the DPF is greater than a preset frequency threshold value.
The above apparatus, optionally, the execution unit includes:
and the calculating subunit is used for inputting the first initial pressure difference value and the second initial pressure difference value into a preset Kalman filter for calculation to obtain a pressure difference estimated value of the DPF at the current moment.
The above apparatus, optionally, the calculating subunit includes:
the determining module is used for determining the acquisition value deviation of the current moment based on the first initial pressure difference value and the second initial pressure difference value;
the execution module is used for obtaining the current Kalman gain according to the acquired value deviation of the current moment and the estimated value deviation of the previous moment of the current moment;
and the calculation module is used for calculating to obtain the differential pressure estimation value of the DPF at the current moment based on the differential pressure estimation value at the previous moment, the Kalman gain and the second initial differential pressure value.
The above apparatus, optionally, the comparing unit includes:
the first execution subunit is used for inquiring a preset limit pressure difference table based on the volume flow and the average temperature of the exhaust gas of the DPF to obtain an initial pressure difference lower limit value;
a determining subunit for determining a differential pressure limit correction factor for the initial differential pressure value based on the carbon loading of the DPF;
and the correcting subunit is used for correcting the initial pressure difference lower limit value based on the pressure difference limit value correcting factor to obtain the current corrected pressure difference lower limit value.
Compared with the prior art, the invention has the following advantages:
the invention provides a fault monitoring method and a device of a DPF (diesel particulate filter), wherein the method comprises the following steps: acquiring the current state parameters of a DPF of a diesel particulate filter; judging whether the state parameters meet preset monitoring enabling conditions or not; under the condition that the state parameters meet the enabling conditions, obtaining a differential pressure estimation value of the DPF at the current moment based on a first initial differential pressure value and a second initial differential pressure value; the first initial differential pressure value is obtained by calculation according to a preset differential pressure model, and the second initial differential pressure value is obtained by collection based on a differential pressure collector which is arranged on the DPF in advance; acquiring a current corrected differential pressure lower limit value, and comparing the differential pressure estimated value with the differential pressure lower limit value; if the estimated pressure difference value is smaller than the lower pressure difference limit value, determining that the DPF is in an initial abnormal state, and recording the duration of the DPF in the initial abnormal state; updating the abnormal times of the DPF under the condition that the duration of the DPF in the initial abnormal state is greater than a preset duration threshold; and if the updated abnormal frequency of the DPF is greater than a preset frequency threshold value, determining that the DPF is in fault. By applying the DPF fault monitoring method provided by the invention, the pressure difference estimated value can be obtained by combining the first initial pressure difference value and the second initial pressure difference value, the accuracy of the pressure difference estimated value can be improved, the abnormal times of the DPF can be recorded, and the fault of the DPF is determined under the condition that the abnormal times are greater than the preset time threshold, so that the fault can be effectively improved, and the DPF monitoring robustness can be improved.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.
FIG. 1 is a flow chart of a method for monitoring a DPF for faults according to the present invention;
FIG. 2 is a schematic structural diagram of a DPF fault monitoring system provided by the present invention;
FIG. 3 is a flow chart for obtaining an estimated value of differential pressure at the present time of DPF according to the present invention;
FIG. 4 is a flowchart of yet another method of a DPF fault monitoring method provided by the present invention;
FIG. 5 is a schematic diagram of a DPF filtration efficiency monitoring strategy provided by the present invention;
FIG. 6 is a schematic structural diagram of a DPF fault monitoring device provided in the present invention;
fig. 7 is a schematic structural diagram of a monitoring device provided in the present invention.
Detailed Description
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.
In this application, 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 a … …" does not exclude the presence of another identical element in a process, method, article, or apparatus that comprises the element.
The embodiment of the invention provides a fault monitoring method for a DPF, which can be applied to a processor of a control device, wherein the processor can be an ECU, and a flow chart of the method is shown in FIG. 1, and specifically comprises the following steps:
s101: and acquiring the current state parameters of the DPF of the diesel particulate filter.
In the embodiment of the invention, the state parameters of the DPF can be acquired in real time under the conditions of power-on of the ECU and starting of the engine.
Optionally, the condition parameters may include any one or combination of differential pressure sensor conditions, exhaust gas volumetric flow, engine speed, fuel injection amount, DPF average temperature, and carbon loading.
S102: and judging whether the state parameters meet preset monitoring enabling conditions, if so, executing S103, otherwise, returning to executing S101.
In an embodiment of the present invention, the monitoring enabling condition may include: the pressure difference sensor state is a preliminary measurement state, the exhaust gas volume flow is in a preset volume flow range, the engine rotating speed is in a preset rotating speed range, the fuel injection amount is in a preset injection amount range, the DPF average temperature is in a preset temperature range, and the carbon loading amount is in a preset carbon loading amount range.
S103: obtaining a differential pressure estimation value of the DPF at the current moment based on a first initial differential pressure value and a second initial differential pressure value; the first initial differential pressure value is obtained through calculation according to a preset differential pressure model, and the second initial differential pressure value is obtained through collection based on a differential pressure collector arranged on the DPF in advance.
In an embodiment of the present invention, the pressure difference model may be:
wherein, Δ P model Is the output of the differential pressure model, i.e., the first initial differential pressure value; mu is the airflow dynamic viscosity coefficient; q is the gas volume flow; v is the volume of the carrier; a is the side length of a small hole on the end face of the filter body; omega s The wall thickness of the small hole; k is a radical of formula wall Is the permeability of the filtration wall; k is a radical of soot Permeability of the granular layer, and omega is the thickness of the cake layer on the filter wall; f is the friction coefficient; l is the length of the small hole; rho g Is the gas density; xi is contractionExpansion inertia loss coefficient; d is the diameter of the carrier.
Specifically, the output of the pressure difference model may be represented by the first pressure drop Δ P cont&exp Second pressure drop Δ P inlet Third pressure drop Δ P outlet A fourth pressure drop Δ P wall And a fifth pressure drop Δ P soot The first pressure drop is caused by the change in cross-section of the gas flowing into and out of the filter body, the second pressure drop is caused by the on-way friction of the exhaust gas flow through the inlet passage, the third pressure drop is caused by the on-way friction of the exhaust gas flow outlet passage, the fourth pressure drop is caused by the exhaust gas flow through the filter wall, and the fifth pressure drop is caused by the exhaust gas flow through the particulate layer on the filter wall.
Wherein, the calculation formula of each pressure drop can be as follows:
in the embodiment of the present invention, the setting manner of the differential pressure sensor is as shown in fig. 2, which is a schematic structural diagram of a monitoring system of a DPF provided in the embodiment of the present invention, and the differential pressure sensor can acquire the differential pressure of the DPF in real time, and the differential pressure acquired by the differential pressure sensor is used as the second initial differential pressure.
S104: and acquiring a current corrected lower limit value of the differential pressure, and comparing the estimated value of the differential pressure with the lower limit value of the differential pressure.
In the embodiment of the invention, the pressure difference estimation value is compared with the pressure difference lower limit value, so that whether the pressure difference estimation value is smaller than the pressure difference lower limit value or not can be determined according to the comparison result.
S105: and if the estimated pressure difference value is smaller than the lower pressure difference limit value, determining that the DPF is in an initial abnormal state, and recording the duration of the DPF in the initial abnormal state.
In the embodiment of the present invention, in the case that the estimated value of the differential pressure is smaller than the lower limit value of the differential pressure, a timer may be started to count time so as to record the duration of the DPF in the initial abnormal state.
S106: and updating the abnormal times of the DPF under the condition that the duration of the DPF in the initial abnormal state is greater than a preset duration threshold.
In the embodiment of the present invention, the time threshold may be set according to actual requirements, and in the case of the duration of the DPF in the initial abnormal state, the counter is triggered to increase by one to update the abnormal times of the DPF.
S107: and judging whether the updated abnormal frequency of the DPF is larger than a preset frequency threshold value, if so, executing S108, otherwise, returning to executing S101.
In the embodiment of the present invention, the threshold of the number of times may be set to any value according to actual requirements, for example, 1, 5, or 10.
S108: determining that the DPF is malfunctioning.
In the embodiment of the present invention, when the abnormal number is greater than the number threshold, it is determined that the filtering efficiency of the DPF is decreased, and the DPF has a failure with low filtering efficiency.
After the DPF is determined to be in fault, alarming information of the DPF fault can be sent out to remind a user of timely processing the fault of the DPF.
By applying the DPF fault monitoring method provided by the invention, a pressure difference estimation value can be obtained by combining the first initial pressure difference value and the second initial pressure difference value, the accuracy of the pressure difference estimation value can be improved, the abnormal times of the DPF can be recorded, and the fault of the DPF is determined according to the condition that the abnormal times are greater than a preset time threshold value, so that the fault of the DPF can be effectively improved, and the DPF monitoring robustness can be improved.
In the method provided by the embodiment of the present invention, based on the implementation process, specifically, a feasible manner of obtaining the estimated value of the pressure difference at the current time of the DPF based on the first initial pressure difference value and the second initial pressure difference value includes:
and inputting the first initial differential pressure value and the second initial differential pressure value into a preset Kalman filter for calculation to obtain a differential pressure estimation value of the DPF at the current moment.
In the embodiment of the invention, the first initial differential pressure value and the second initial differential pressure value are calculated by using the Kalman filter, so that the current optimal differential pressure estimation value can be obtained.
In the method provided in the embodiment of the present invention, based on the implementation process, specifically, the inputting the first initial differential pressure value and the second initial differential pressure value into a preset kalman filter to perform calculation to obtain a differential pressure estimation value of the DPF at the current time includes, as shown in fig. 3:
s301: and determining the deviation of the acquisition value at the current moment based on the first initial differential pressure value and the second initial differential pressure value.
In the embodiment of the present invention, the difference between the first initial differential pressure value and the second initial differential pressure value may be determined as the acquired value deviation e at the current time m 。
S302: and obtaining the current Kalman gain according to the acquired value deviation of the current moment and the estimated value deviation of the previous moment of the current moment.
In the embodiment of the present invention, the kalman gain may be calculated as follows:
where KG is the Kalman gain, e e (t-1) is the deviation of the estimated value at the previous time, i.e. the deviation of the estimated value calculated last time, and if the current calculation is the first time, the deviation of the estimated value at the previous time may be a preset initial value e e0 ；e m Is the deviation of the collected value.
S303: and calculating to obtain the pressure difference estimated value of the DPF based on the pressure difference estimated value at the previous moment, the Kalman gain and the second initial pressure difference value.
In the embodiment of the present invention, the estimated pressure difference value may be calculated as follows:
x e (t)＝x e (t-1)+KG[x m -x e (t-1)]
wherein x is e (t) is the estimated value of this calculation, i.e. the estimated value of the differential pressure at the current moment, x e (t-1) is the estimated value of the pressure difference at the previous moment, that is, the estimated value calculated last time, and if the current calculation is the first time, the estimated value of the pressure difference at the previous moment can be the preset initial estimated value x e0 ；x m Is the current acquisition value.
After the differential pressure estimation value of the DPF is calculated, the estimation value deviation of the current time can be calculated according to the kalman gain and the estimation value deviation of the previous time, and the method for calculating the estimation value deviation of the current time is as follows:
e e (t)＝(1-KG)*e e (t-1)
wherein e is e (t) is the estimated value deviation at the current time.
In the embodiment of the invention, the pressure difference estimated value of the DPF is obtained through calculation of the Kalman filter, so that the calculation precision of the pressure difference value is improved.
In the method provided in the embodiment of the present invention, based on the foregoing implementation process, specifically, the determining whether the state parameter meets a preset monitoring enabling condition includes:
judging whether the state of the differential pressure sensor in the state parameters is a prepared measurement state or not;
judging whether the volume flow of the waste gas in the state parameters is in a preset volume flow range or not;
judging whether the engine rotating speed in the state parameters is in a preset rotating speed range or not;
judging whether the fuel injection quantity in the state parameters is in a preset injection quantity range or not;
judging whether the average temperature of the DPF in the state parameters is in a preset temperature range or not;
judging whether the carbon loading capacity in the state parameters is in a preset carbon loading capacity range or not;
when the judgment results of the above judgments are all yes, determining that the state parameter meets the monitoring enabling condition;
and under the condition that any judgment result of the judgment is negative, determining that the state parameter does not meet the monitoring enabling condition.
In the embodiment of the present invention, the preliminary measurement state of the differential pressure sensor refers to a state in which the differential pressure sensor is ready.
Specifically, the volume flow range, the rotation speed range, the injection amount range, the temperature range and the carbon loading amount range can be set according to actual requirements, for example, the volume flow range can be 1000-1800m ^3/h, the rotation speed range can be 1000-2000 rpm, and the injection amount range can be 15-90 kg/h; the average temperature may be 250 to 550 ℃; the carbon loading may range from 0.5 to 3g/L.
In the method provided in the embodiment of the present invention, based on the foregoing implementation process, specifically, the acquiring a current corrected lower limit value of the pressure difference includes:
inquiring a preset limit pressure difference table based on the volume flow and the average temperature of the exhaust gas of the DPF to obtain an initial pressure difference lower limit value;
determining a differential pressure limit correction factor for the initial differential pressure value based on the carbon loading of the DPF;
and correcting the initial pressure difference lower limit value based on the pressure difference limit value correction factor to obtain the current corrected pressure difference lower limit value.
In an embodiment of the present invention, the product of the initial lower pressure difference limit and the pressure difference limit correction factor may be used as the currently corrected lower pressure difference limit.
Referring to fig. 4, a flowchart of another method of the DPF failure monitoring method according to the embodiment of the present invention is shown, where when the ECU is powered on and the engine is started, it is determined whether an enabling condition is met, and an optimal differential pressure estimation value is calculated when the enabling condition is met, where the optimal differential pressure estimation value is a differential pressure estimation value calculated by the kalman filter; and starting a timer under the condition that the optimal differential pressure estimation value is smaller than the differential pressure lower limit value, if the timing time of the timer is larger than a preset time threshold, adding one to the counter, and reporting the fault of low DPF filtration efficiency under the condition that the count of the counter is larger than a preset time threshold.
Referring to fig. 5, a schematic diagram of a DPF filtration efficiency monitoring strategy according to an embodiment of the present invention is provided.
The calculated value of the pressure difference model and the acquired value of the pressure difference sensor can be input into a Kalman filter to obtain the optimal pressure difference estimated value output by the Kalman filter; a limit pressure difference table can be inquired based on the volume flow of the exhaust gas and the average temperature of the DPF to obtain a lower limit value of the pressure difference; determining a pressure difference limit correction factor based on the carbon loading capacity, obtaining a corrected pressure difference lower limit based on the pressure difference lower limit and the pressure difference limit correction factor, starting a timer to time under the condition that the optimal pressure difference estimated value is smaller than the corrected pressure difference lower limit, and reporting a fault under the condition that the timing duration of the counter is larger than the time limit.
Corresponding to the method illustrated in fig. 1, an embodiment of the present invention further provides a DPF failure monitoring apparatus for specifically implementing the method illustrated in fig. 1, where a schematic structural diagram of the DPF failure monitoring apparatus provided in the embodiment of the present invention is illustrated in fig. 6, and specifically includes:
the acquisition unit 601 is used for acquiring the current state parameters of the DPF of the diesel particulate filter;
a determining unit 602, configured to determine whether the state parameter meets a preset monitoring enabling condition;
an executing unit 603, configured to obtain a differential pressure estimated value of the DPF at the current time based on a first initial differential pressure value and a second initial differential pressure value when the state parameter satisfies the enabling condition; the first initial differential pressure value is obtained by calculation according to a preset differential pressure model, and the second initial differential pressure value is obtained by collection based on a differential pressure collector which is arranged on the DPF in advance;
a comparison unit 604, configured to obtain a current corrected lower pressure difference limit, and compare the pressure difference estimation value with the lower pressure difference limit;
a first determining unit 605, configured to determine that the DPF is in an initial abnormal state if the estimated pressure difference value is smaller than the lower pressure difference limit value, and record a duration of the DPF in the initial abnormal state;
an updating unit 606, configured to update the abnormal times of the DPF when a duration of the DPF in the initial abnormal state is greater than a preset duration threshold;
a second determining unit 607, configured to determine that the DPF has a failure if the updated abnormal number of times of the DPF is greater than a preset number threshold.
In an embodiment of the present invention, based on the above scheme, specifically, the execution unit 603 includes:
and the calculating subunit is used for inputting the first initial differential pressure value and the second initial differential pressure value into a preset Kalman filter for calculation to obtain a differential pressure estimation value of the DPF at the current moment.
In an embodiment provided by the present invention, based on the above scheme, specifically, the calculating subunit includes:
the determining module is used for determining the deviation of the acquisition value at the current moment based on the first initial differential pressure value and the second initial differential pressure value;
the execution module is used for obtaining the current Kalman gain according to the acquired value deviation of the current moment and the estimated value deviation of the previous moment of the current moment;
and the calculation module is used for calculating to obtain the pressure difference estimated value of the DPF at the current moment based on the pressure difference estimated value at the previous moment, the Kalman gain and the second initial pressure difference value.
In an embodiment of the present invention, based on the above scheme, specifically, the comparing unit 604 includes:
the first execution subunit is used for inquiring a preset limit pressure difference table based on the volume flow of the exhaust gas of the DPF and the average temperature to obtain an initial pressure difference lower limit value;
a determining subunit for determining a differential pressure limit correction factor for the initial differential pressure value based on the carbon loading of the DPF;
and the correcting subunit is used for correcting the initial pressure difference lower limit value based on the pressure difference limit value correcting factor to obtain the current corrected pressure difference lower limit value.
In an embodiment provided by the present invention, based on the above scheme, specifically, the determining unit 602 is configured to:
judging whether the state of the differential pressure sensor in the state parameters is a prepared measurement state or not;
judging whether the engine rotating speed in the state parameters is in a preset rotating speed range or not;
judging whether the fuel injection quantity in the state parameters is in a preset injection quantity range or not;
judging whether the average temperature of the DPF in the state parameters is in a preset temperature range or not;
judging whether the carbon loading capacity in the state parameters is in a preset carbon loading capacity range or not;
when the judgment results of the above judgments are all yes, determining that the state parameter meets the monitoring enabling condition;
and under the condition that any judgment result of the judgment is negative, determining that the state parameter does not meet the monitoring enabling condition.
In an embodiment provided by the present invention, based on the above scheme, specifically, the DPF failure monitoring apparatus further includes:
and the processing unit is configured to return to trigger the obtaining unit 601 if the updated abnormal DPF frequency is not greater than the frequency threshold.
The specific principle and implementation process of each unit and module in the DPF fault monitoring apparatus disclosed in the embodiment of the present invention are the same as those of the DPF fault monitoring method disclosed in the embodiment of the present invention, and reference may be made to corresponding parts in the DPF fault monitoring method provided in the embodiment of the present invention, which are not described herein again.
The embodiment of the invention also provides a storage medium, which comprises a stored instruction, wherein when the instruction runs, the device where the storage medium is located is controlled to execute the DPF fault monitoring method.
The structural diagram of the monitoring device shown in fig. 7 specifically includes a memory 701 and one or more instructions 702, where the one or more instructions 702 are stored in the memory 701 and configured to be executed by the one or more processors 703 to perform the following operations, where the one or more instructions 702 are stored in the memory 701:
acquiring the current state parameters of the DPF of the diesel particulate filter;
judging whether the state parameters meet preset monitoring enabling conditions or not;
under the condition that the state parameters meet the enabling conditions, obtaining a pressure difference estimated value of the DPF at the current moment based on a first initial pressure difference value and a second initial pressure difference value; the first initial differential pressure value is obtained by calculation according to a preset differential pressure model, and the second initial differential pressure value is obtained by collection based on a differential pressure collector which is arranged on the DPF in advance;
acquiring a current corrected differential pressure lower limit value, and comparing the differential pressure estimated value with the differential pressure lower limit value;
if the estimated pressure difference value is smaller than the lower pressure difference limit value, determining that the DPF is in an initial abnormal state, and recording the duration of the DPF in the initial abnormal state;
updating the abnormal times of the DPF under the condition that the duration of the DPF in the initial abnormal state is greater than a preset duration threshold;
and if the updated abnormal frequency of the DPF is greater than a preset frequency threshold, determining that the DPF has a fault.
It should be noted that, in the present specification, the embodiments are all described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments may be referred to each other. For the device-like embodiment, since it is basically similar to the method embodiment, the description is simple, and reference may be made to the partial description of the method embodiment for relevant points.
Finally, it should also be noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising a … …" does not exclude the presence of another identical element in a process, method, article, or apparatus that comprises the element.
For convenience of description, the above devices are described as being divided into various units by function, and are described separately. Of course, the functions of the units may be implemented in the same software and/or hardware or in a plurality of software and/or hardware when implementing the invention.
From the above description of the embodiments, it is clear to those skilled in the art that the present invention can be implemented by software plus necessary general hardware platform. Based on such understanding, the technical solutions of the present invention may be embodied in the form of a software product, which may be stored in a storage medium, such as ROM/RAM, magnetic disk, optical disk, etc., and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute the method according to the embodiments or some parts of the embodiments.
The method for monitoring the fault of the DPF provided by the present invention is described in detail above, and the principle and the implementation of the present invention are explained in the present document by applying specific examples, and the description of the above examples is only used to help understanding the method of the present invention and the core idea thereof; meanwhile, for a person skilled in the art, according to the idea of the present invention, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present invention.
Claims (6)
1. A method of fault monitoring a DPF, comprising:
acquiring the current state parameters of the DPF of the diesel particulate filter;
judging whether the state parameters meet preset monitoring enabling conditions or not;
under the condition that the state parameters meet the enabling conditions, obtaining a differential pressure estimation value of the DPF at the current moment based on a first initial differential pressure value and a second initial differential pressure value; the first initial differential pressure value is obtained by calculation according to a preset differential pressure model, and the second initial differential pressure value is obtained by collection based on a differential pressure collector which is arranged on the DPF in advance;
acquiring a current corrected lower limit value of the differential pressure, and comparing the estimated value of the differential pressure with the lower limit value of the differential pressure;
if the estimated pressure difference value is smaller than the lower pressure difference limit value, determining that the DPF is in an initial abnormal state, and recording the duration of the DPF in the initial abnormal state;
updating the abnormal times of the DPF under the condition that the duration of the DPF in the initial abnormal state is greater than a preset duration threshold;
if the updated abnormal frequency of the DPF is larger than a preset frequency threshold value, determining that the DPF has a fault;
wherein the obtaining of the estimated value of the pressure difference of the DPF at the current time based on the first initial pressure difference value and the second initial pressure difference value comprises:
inputting the first initial differential pressure value and the second initial differential pressure value into a preset Kalman filter for calculation to obtain a differential pressure estimation value of the DPF at the current moment;
the step of inputting the first initial differential pressure value and the second initial differential pressure value into a preset kalman filter for calculation to obtain the estimated differential pressure value of the DPF at the current moment includes:
determining a deviation of the acquisition value at the current moment based on the first initial differential pressure value and the second initial differential pressure value;
obtaining a current Kalman gain according to the acquired value deviation of the current moment and the estimated value deviation of the previous moment of the current moment;
and calculating to obtain the differential pressure estimation value of the DPF at the current moment based on the differential pressure estimation value of the previous moment, the Kalman gain and the second initial differential pressure value.
2. The method according to claim 1, wherein the determining whether the state parameter satisfies a preset monitoring enabling condition comprises:
judging whether the state of the differential pressure sensor in the state parameters is a prepared measurement state or not;
judging whether the engine rotating speed in the state parameters is in a preset rotating speed range or not;
judging whether the fuel injection quantity in the state parameters is in a preset injection quantity range or not;
judging whether the average temperature of the DPF in the state parameters is in a preset temperature range or not;
judging whether the carbon loading capacity in the state parameters is in a preset carbon loading capacity range or not;
when the judgment results of the above judgments are all yes, determining that the state parameter meets the monitoring enabling condition;
and under the condition that any judgment result of the judgment is negative, determining that the state parameter does not meet the monitoring enabling condition.
3. The method of claim 1, wherein the obtaining the current corrected lower differential pressure value comprises:
inquiring a preset limit pressure difference table based on the volume flow and the average temperature of the exhaust gas of the DPF to obtain an initial pressure difference lower limit value;
determining a differential pressure limit correction factor for the initial differential pressure value based on the carbon loading of the DPF;
and correcting the initial pressure difference lower limit value based on the pressure difference limit value correction factor to obtain the current corrected pressure difference lower limit value.
4. The method of claim 1, further comprising:
and if the updated abnormal frequency of the DPF is not greater than the frequency threshold value, returning to the step of obtaining the current state parameters of the DPF of the diesel particulate filter.
5. A failure monitoring apparatus of a DPF, comprising:
the device comprises an acquisition unit, a control unit and a control unit, wherein the acquisition unit is used for acquiring the current state parameters of the DPF of the diesel particulate filter;
the judging unit is used for judging whether the state parameters meet preset monitoring enabling conditions or not;
the execution unit is used for obtaining a differential pressure estimation value of the DPF at the current moment based on a first initial differential pressure value and a second initial differential pressure value under the condition that the state parameter meets the enabling condition; the first initial differential pressure value is obtained by calculation according to a preset differential pressure model, and the second initial differential pressure value is obtained by collection based on a differential pressure collector which is arranged on the DPF in advance;
the comparison unit is used for acquiring the current corrected lower limit value of the differential pressure and comparing the estimated value of the differential pressure with the lower limit value of the differential pressure;
the first determining unit is used for determining that the DPF is in an initial abnormal state if the estimated pressure difference value is smaller than the lower pressure difference limit value, and recording the duration of the DPF in the initial abnormal state;
the updating unit is used for updating the abnormal times of the DPF under the condition that the duration of the DPF in the initial abnormal state is greater than a preset duration threshold;
a second determining unit, configured to determine that the DPF has a failure if the updated abnormal DPF number is greater than a preset number threshold;
wherein the execution unit includes:
the calculation subunit is configured to input the first initial pressure difference value and the second initial pressure difference value into a preset kalman filter for calculation, so as to obtain a pressure difference estimation value of the DPF at the current time;
wherein the computing subunit comprises:
the determining module is used for determining the deviation of the acquisition value at the current moment based on the first initial differential pressure value and the second initial differential pressure value;
the execution module is used for obtaining the current Kalman gain according to the acquired value deviation of the current moment and the estimated value deviation of the previous moment of the current moment;
and the calculation module is used for calculating to obtain the differential pressure estimation value of the DPF at the current moment based on the differential pressure estimation value at the previous moment, the Kalman gain and the second initial differential pressure value.
6. The apparatus of claim 5, wherein the alignment unit comprises:
the first execution subunit is used for inquiring a preset limit pressure difference table based on the volume flow of the exhaust gas of the DPF and the average temperature to obtain an initial pressure difference lower limit value;
a determining subunit for determining a differential pressure limit correction factor for the initial differential pressure value based on the carbon loading of the DPF;
and the correcting subunit is used for correcting the initial pressure difference lower limit value based on the pressure difference limit value correcting factor to obtain the current corrected pressure difference lower limit value.
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| CN114370324B (en) * | 2022-01-19 | 2023-01-06 | 潍柴动力股份有限公司 | Method for diagnosing DPF system fault and vehicle |
| CN114934836B (en) * | 2022-04-24 | 2023-06-23 | 潍柴动力股份有限公司 | DPF trapping efficiency diagnosis method and device and driving equipment |
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| US8281580B2 (en) * | 2010-01-19 | 2012-10-09 | GM Global Technology Operations LLC | Method and apparatus for monitoring a particulate filter |
| GB2504714A (en) * | 2012-08-07 | 2014-02-12 | Gm Global Tech Operations Inc | Evaluating a pressure drop across a particulate filter in an exhaust system of an automotive internal combustion engine |
| CN104863679B (en) * | 2015-03-31 | 2017-05-24 | 凯龙高科技股份有限公司 | DPF system carbon loading capacity estimation and blocking state judgment method |
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