CA3131581A1 - Failure detection method for scr urea injection devices - Google Patents
Failure detection method for scr urea injection devices Download PDFInfo
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- CA3131581A1 CA3131581A1 CA3131581A CA3131581A CA3131581A1 CA 3131581 A1 CA3131581 A1 CA 3131581A1 CA 3131581 A CA3131581 A CA 3131581A CA 3131581 A CA3131581 A CA 3131581A CA 3131581 A1 CA3131581 A1 CA 3131581A1
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N11/00—Monitoring or diagnostic devices for exhaust-gas treatment apparatus, e.g. for catalytic activity
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
- F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
- F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
- F01N3/18—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control
- F01N3/20—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control specially adapted for catalytic conversion ; Methods of operation or control of catalytic converters
- F01N3/2066—Selective catalytic reduction [SCR]
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N2610/00—Adding substances to exhaust gases
- F01N2610/02—Adding substances to exhaust gases the substance being ammonia or urea
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N2610/00—Adding substances to exhaust gases
- F01N2610/14—Arrangements for the supply of substances, e.g. conduits
- F01N2610/148—Arrangement of sensors
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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
- Y02T10/12—Improving ICE efficiencies
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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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- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Health & Medical Sciences (AREA)
- Toxicology (AREA)
- Exhaust Gas After Treatment (AREA)
Abstract
The present invention relates a failure detection method for SCR urea inject devices, and belongs to vehicle mounted device detection technical field; the present failure detection method can realize real time failure detection of the SCR urea inject devices when an automobile is running, on a basis of monitoring and acquiring in real time the urea solution pressure in the SCR urea inject device, by making deviation comparisons between the quartile deviations of the urea solution pressure values in a certain detection cycle and a standard quartile deviation and with scientific statistical methods, and under failure conditions, and remind the driver in time of the detection result, so as to avoid influences from imbalance urea solution outflow, and unstable pressure on safety and stability of vehicle running.
Description
FAILURE DETECTION METHOD FOR SCR UREA INJECTION DEVICES
Technical field The present invention relates a failure detection method for SCR urea inject devices, and belongs to vehicle mounted device detection technical field.
Background technology With constant development and growth of the automobile industry in China, market shares of commercial vehicles continue to increase, as a primary power source for commercial vehicles, a demanding and delivery amount of diesel engines rises every year. While providing sufficient displacement, excellent power performances and fuel economy, the diesel engines bring environment pollution, which becomes an urgent matter for vehicle emission management, on July 1st 2019, an emission standard of China VI Standards on heavy-duty diesel engines has been implemented all over the country, and to reduce emission during working of the diesel engines, usually SCR (Selective Catalytic Reduction) of the tail gas treatment system is applied.
Technical principles of SCR are to selectively convert nitrogen oxide to be nitrogen and water by use of a reductant and with the aid of a catalyst in an oxygen-enriched environment. The reductant used at present is urea solution (such as urea solution with a mass concentration of 32.5%), which under high temperature will be dissolved into NH3 and CO2, which will in turn react chemically with the NO and NO2 in the tail gas of diesel vehicles, produce nitrogen and water, and satisfy requirements of emission regulations.
During SCR, the urea solution is pressurized by a urea pump, and injected after atomized by urea nozzles. Specifically, during working, three processes, namely, pressurization, injection and withdrawal happen. During pressurization, the urea pump accumulates pressure, so that pressure in the urea tank increases gently and is maintained at a normal working level (pressurization of the device is done, and the pressure is kept at the normal working pressure);
when injection conditions are met, the engine control unit or DCU(Dosing Control Unit) sends an instruction to open the nozzle; and when the engine work is done, power is off, the urea Date Recue/Date Received 2022-01-06 pump starts to withdraw, and to prevent urea crystallization and blockage, the pump will withdraw remaining urea in the ducts and the nozzle back to the urea tank.
During the injection stage, an opening degree of the SCR urea inject device changes periodically along with time, so as to realize one and another injection cycle of the urea solution;
when the nozzle is opened, the urea solution is injected, pressure in the outlet declines, when receiving signals of insufficient urea solution pressure in the outlet, the urea pump will increase a duty ratio to supplement more urea solution into the outlet to compensate the pressure.
However, when problems such as urea pump deterioration and inlet filter blockage happen in the SCR urea inject device occur, it will be more difficult for the urea pump to compensate pressure in the outlet, so that after the nozzle opening, it becomes difficult to supplement pressure to the urea solution in the outlet, fluctuation of the pressure is more apparent, consequent problems such as imbalance and unstable urea solution outflow will affect running of the SCR after treatment system, degrade vehicle running efficiencies, and may even influence safety and stability of vehicle running and jeopardize vehicle safety.
Therefore, it is imperative in the art to provide a failure detection method for SCR urea injection devices Summary of the invention In view of the foregoing problems and/ or other problems, one aspect of the present invention provides a failure detection method for SCR urea inject devices, wherein:
The failure detection method comprises following steps:
Step 1): acquiring on a real time basis pressure values of urea solution in outlet ducts of the SCR urea inject device;
Step 2): defining a detection cycle T, dividing chronologically the detection cycle T into n time ranges ti (ti, f2 .. tn); setting an accumulated abnormality value at an initial point of the detection cycle T to be zero;
Technical field The present invention relates a failure detection method for SCR urea inject devices, and belongs to vehicle mounted device detection technical field.
Background technology With constant development and growth of the automobile industry in China, market shares of commercial vehicles continue to increase, as a primary power source for commercial vehicles, a demanding and delivery amount of diesel engines rises every year. While providing sufficient displacement, excellent power performances and fuel economy, the diesel engines bring environment pollution, which becomes an urgent matter for vehicle emission management, on July 1st 2019, an emission standard of China VI Standards on heavy-duty diesel engines has been implemented all over the country, and to reduce emission during working of the diesel engines, usually SCR (Selective Catalytic Reduction) of the tail gas treatment system is applied.
Technical principles of SCR are to selectively convert nitrogen oxide to be nitrogen and water by use of a reductant and with the aid of a catalyst in an oxygen-enriched environment. The reductant used at present is urea solution (such as urea solution with a mass concentration of 32.5%), which under high temperature will be dissolved into NH3 and CO2, which will in turn react chemically with the NO and NO2 in the tail gas of diesel vehicles, produce nitrogen and water, and satisfy requirements of emission regulations.
During SCR, the urea solution is pressurized by a urea pump, and injected after atomized by urea nozzles. Specifically, during working, three processes, namely, pressurization, injection and withdrawal happen. During pressurization, the urea pump accumulates pressure, so that pressure in the urea tank increases gently and is maintained at a normal working level (pressurization of the device is done, and the pressure is kept at the normal working pressure);
when injection conditions are met, the engine control unit or DCU(Dosing Control Unit) sends an instruction to open the nozzle; and when the engine work is done, power is off, the urea Date Recue/Date Received 2022-01-06 pump starts to withdraw, and to prevent urea crystallization and blockage, the pump will withdraw remaining urea in the ducts and the nozzle back to the urea tank.
During the injection stage, an opening degree of the SCR urea inject device changes periodically along with time, so as to realize one and another injection cycle of the urea solution;
when the nozzle is opened, the urea solution is injected, pressure in the outlet declines, when receiving signals of insufficient urea solution pressure in the outlet, the urea pump will increase a duty ratio to supplement more urea solution into the outlet to compensate the pressure.
However, when problems such as urea pump deterioration and inlet filter blockage happen in the SCR urea inject device occur, it will be more difficult for the urea pump to compensate pressure in the outlet, so that after the nozzle opening, it becomes difficult to supplement pressure to the urea solution in the outlet, fluctuation of the pressure is more apparent, consequent problems such as imbalance and unstable urea solution outflow will affect running of the SCR after treatment system, degrade vehicle running efficiencies, and may even influence safety and stability of vehicle running and jeopardize vehicle safety.
Therefore, it is imperative in the art to provide a failure detection method for SCR urea injection devices Summary of the invention In view of the foregoing problems and/ or other problems, one aspect of the present invention provides a failure detection method for SCR urea inject devices, wherein:
The failure detection method comprises following steps:
Step 1): acquiring on a real time basis pressure values of urea solution in outlet ducts of the SCR urea inject device;
Step 2): defining a detection cycle T, dividing chronologically the detection cycle T into n time ranges ti (ti, f2 .. tn); setting an accumulated abnormality value at an initial point of the detection cycle T to be zero;
2 Date Recue/Date Received 2022-01-06 Step 3): drawing a box plot for urea solution pressure values corresponding to the time range ti in turn, analyzing the box plot, and judging whether there is any abnormality in the time range ti;
when there is an abnormality, increasing the accumulated abnormality value by 1, otherwise don't increase the accumulated abnormality value, In step 3), a way to judge the abnormality is: to obtain corresponding upper quartile and lower quartile according to a biggest pressure value and a smallest pressure value, calculate a difference between the upper quartile and the lower quartile, which is counted as a quartile deviation of the time range; comparing the quartile deviation of the time range with a standard quartile deviation measured in advance, and when the quartile deviation is bigger than the standard quartile deviation, it is judged that the abnormality occurs;
Step 4): when the accumulated abnormality value reaches a threshold value, sending a failure warning, detection is over; when the accumulated abnormality value doesn't reach the threshold value, increasing a sequence number of the time range ti by one; and Step 5): when a value of the sequence number i is smaller than or equals n, returning to step 3);
when the value of the sequence number I is bigger than n, returning to step 2) to start another detection cycle.
Preferably, a value of the standard quartile deviation and a value of the threshold value have been got in advance by analogue analysis in a laboratory.
Preferably, in step 1), obtaining in real time the pressure values of the urea solution in the outlet ducts of the SCR urea inject device is done by providing a pressure sensor on the outlet ducts of the SCR urea inject device.
The present invention provides a failure detection method for SCR urea inject devices; the present failure detection method can realize real time failure detection of the SCR urea inject devices when an automobile is running, on a basis of monitoring and acquiring in real time the urea solution pressure in the SCR urea inject device, by making deviation comparisons between the quartile deviations of the urea solution pressure values in a certain detection cycle and a
when there is an abnormality, increasing the accumulated abnormality value by 1, otherwise don't increase the accumulated abnormality value, In step 3), a way to judge the abnormality is: to obtain corresponding upper quartile and lower quartile according to a biggest pressure value and a smallest pressure value, calculate a difference between the upper quartile and the lower quartile, which is counted as a quartile deviation of the time range; comparing the quartile deviation of the time range with a standard quartile deviation measured in advance, and when the quartile deviation is bigger than the standard quartile deviation, it is judged that the abnormality occurs;
Step 4): when the accumulated abnormality value reaches a threshold value, sending a failure warning, detection is over; when the accumulated abnormality value doesn't reach the threshold value, increasing a sequence number of the time range ti by one; and Step 5): when a value of the sequence number i is smaller than or equals n, returning to step 3);
when the value of the sequence number I is bigger than n, returning to step 2) to start another detection cycle.
Preferably, a value of the standard quartile deviation and a value of the threshold value have been got in advance by analogue analysis in a laboratory.
Preferably, in step 1), obtaining in real time the pressure values of the urea solution in the outlet ducts of the SCR urea inject device is done by providing a pressure sensor on the outlet ducts of the SCR urea inject device.
The present invention provides a failure detection method for SCR urea inject devices; the present failure detection method can realize real time failure detection of the SCR urea inject devices when an automobile is running, on a basis of monitoring and acquiring in real time the urea solution pressure in the SCR urea inject device, by making deviation comparisons between the quartile deviations of the urea solution pressure values in a certain detection cycle and a
3 Date Recue/Date Received 2022-01-06 standard quartile deviation and with scientific statistical methods, and under failure conditions, and remind the driver in time of the detection result, so as to avoid influences from imbalance urea solution outflow, and unstable pressure on safety and stability of vehicle running.
Brief description of the drawings Figure 1 is a flowchart diagram showing a failure detection method for SCR
urea injection system in an embodiment of the present invention;
Figure 2 is a simple structural diagram showing the SCR urea inject device;
Figure 3 is a box plot in embodiment 1 of the present invention; and Figure 4 is another box plot in embodiment 1 of the present invention.
Embodiments The present invention will be further described by specific embodiments below, but the present invention is not limited to these specific embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, in case of no conflict, the following embodiments and the features in the embodiments can be combined with each other.
Components of the SCR urea inject device, as shown in figure 2, are mainly a urea tank 1, a urea pump 2, outlet ducts 3, an outlet 4, a nozzle 5, a pressure sensor 6 and a controller 7.
Wherein, the urea tank 1 stores the urea solution; the urea pump 2 extracts or returns the urea solution from the urea tank 1, the urea tank 1 is communicated with the urea pump 2 by extraction ducts 12 and returning ducts 21, an inlet 120 and a filter are provided in the extraction ducts 12, a solution returning opening 210 is provided in the returning ducts 12; the urea solution, extracted by the urea pump 2 with the extraction ducts 12, enters the outlet ducts
Brief description of the drawings Figure 1 is a flowchart diagram showing a failure detection method for SCR
urea injection system in an embodiment of the present invention;
Figure 2 is a simple structural diagram showing the SCR urea inject device;
Figure 3 is a box plot in embodiment 1 of the present invention; and Figure 4 is another box plot in embodiment 1 of the present invention.
Embodiments The present invention will be further described by specific embodiments below, but the present invention is not limited to these specific embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, in case of no conflict, the following embodiments and the features in the embodiments can be combined with each other.
Components of the SCR urea inject device, as shown in figure 2, are mainly a urea tank 1, a urea pump 2, outlet ducts 3, an outlet 4, a nozzle 5, a pressure sensor 6 and a controller 7.
Wherein, the urea tank 1 stores the urea solution; the urea pump 2 extracts or returns the urea solution from the urea tank 1, the urea tank 1 is communicated with the urea pump 2 by extraction ducts 12 and returning ducts 21, an inlet 120 and a filter are provided in the extraction ducts 12, a solution returning opening 210 is provided in the returning ducts 12; the urea solution, extracted by the urea pump 2 with the extraction ducts 12, enters the outlet ducts
4 Date Recue/Date Received 2022-01-06 3, passes the outlet 4, reaches the nozzle 5, and is injected through the nozzle 5 after opening of the switch on the nozzle 5.
The pressure sensor 6 for monitoring the urea solution pressure in real time is provided on the outlet ducts 3, and transmits the urea solution pressure values obtained in real time to the controller 7. The controller 7 will control work of the urea pump 2, the pressure sensor 6 and the nozzle 5.
As is stated in the background art, when the nozzle 5 is opened, the urea solution is injected, pressure in the outlet ducts 3 declines, the pressure sensor 6 sends the urea solution pressure values to the controller 7, which will analyze to get signals showing insufficient urea solution pressure in the outlet ducts 3, and instruct the urea pump 2 to extract the urea solution into the outlet ducts 3 to compensate the pressure therein.
However, if problems such as deterioration of the urea pump 2, blockage of the inlet 120 and the filter happen, it will be difficult for the urea pump 2 to compensate pressure in the outlet ducts 3, which will in turn make it more difficult to compensate the urea solution pressure in the outlet ducts 3 after opening of the nozzle 5, fluctuation of the pressure therein is more apparent, and consequent imbalance and instability of the urea solution will affect running of the SCR
after treatment system.
Therefore, in an embodiment of the present invention, a failure detection method for SCR urea inject devices is provided, comprising following steps:
Step 1): acquiring pressure values of the urea solution in the outlet ducts of the SCR urea inject device in a real time basis.
Specifically, as shown in figure 1, the pressure sensor 6 provided on the outlet ducts 3 of the device is used to obtain the urea solution pressure values and transmit data to the controller 7.
Step 2): defining a detection cycle T, and dividing the detection cycle T into n time ranges ti .. t2 tn); and setting an accumulated abnormality value at the beginning of the detection cycle T to be zero;
The pressure sensor 6 for monitoring the urea solution pressure in real time is provided on the outlet ducts 3, and transmits the urea solution pressure values obtained in real time to the controller 7. The controller 7 will control work of the urea pump 2, the pressure sensor 6 and the nozzle 5.
As is stated in the background art, when the nozzle 5 is opened, the urea solution is injected, pressure in the outlet ducts 3 declines, the pressure sensor 6 sends the urea solution pressure values to the controller 7, which will analyze to get signals showing insufficient urea solution pressure in the outlet ducts 3, and instruct the urea pump 2 to extract the urea solution into the outlet ducts 3 to compensate the pressure therein.
However, if problems such as deterioration of the urea pump 2, blockage of the inlet 120 and the filter happen, it will be difficult for the urea pump 2 to compensate pressure in the outlet ducts 3, which will in turn make it more difficult to compensate the urea solution pressure in the outlet ducts 3 after opening of the nozzle 5, fluctuation of the pressure therein is more apparent, and consequent imbalance and instability of the urea solution will affect running of the SCR
after treatment system.
Therefore, in an embodiment of the present invention, a failure detection method for SCR urea inject devices is provided, comprising following steps:
Step 1): acquiring pressure values of the urea solution in the outlet ducts of the SCR urea inject device in a real time basis.
Specifically, as shown in figure 1, the pressure sensor 6 provided on the outlet ducts 3 of the device is used to obtain the urea solution pressure values and transmit data to the controller 7.
Step 2): defining a detection cycle T, and dividing the detection cycle T into n time ranges ti .. t2 tn); and setting an accumulated abnormality value at the beginning of the detection cycle T to be zero;
5 Date Recue/Date Received 2022-01-06 Step 3): drawing box plots for the urea solution pressure values corresponding to the time ranges t, sequentially and analyzing the box plots to judge whether there is any abnormality in the time range ti; when there is an abnormality, increase the accumulated abnormality value by 1, otherwise do not increase the accumulated abnormality value.
.. In step 2), the way to judge abnormalities is: to obtain an upper quartile and a lower quartile corresponding to the biggest pressure value and the lowest pressure value in the box plot, calculate a difference between the upper quartile and the lower quartile, which is counted as a quartile deviation of the present time range; compare the quartile deviation of the present time range with a standard quartile deviation measured in advance, and when the quartile deviation is bigger than the standard quartile deviation, it is judged that an abnormality occurs.
Step 4): when the accumulated abnormality value reaches a threshold value, sending a failure warning, the detection is over; when the accumulated abnormality value doesn't reach the threshold value, increasing a sequence number i of the time range ti by 1;
Step 5): when a value of the sequence number i is smaller than or equals n, returning to step 3);
and when the value of the sequence number iI is bigger than n, entering next detection cycle.
To ease illustration, the technical terms in the foregoing description are shown by symbols, and concrete meanings of the symbols will be given in the following paragraphs in conjunction with the technical solution:
T is a detection cycle.
.................................................. The detection cycle T is divided into n time ranges ti (ti, t2 tn); and ti is any of the time ranges.
The detection cycle T can be determined by the user based on current application conditions and demands. Those skilled in the art can choose an appropriate value according to actual situations, to reflect the status of the SCR urea inject device, and identify failures with high accuracy and efficiency, which will be acceptable if no abnormality is missed or wrongly detected.
.. In step 2), the way to judge abnormalities is: to obtain an upper quartile and a lower quartile corresponding to the biggest pressure value and the lowest pressure value in the box plot, calculate a difference between the upper quartile and the lower quartile, which is counted as a quartile deviation of the present time range; compare the quartile deviation of the present time range with a standard quartile deviation measured in advance, and when the quartile deviation is bigger than the standard quartile deviation, it is judged that an abnormality occurs.
Step 4): when the accumulated abnormality value reaches a threshold value, sending a failure warning, the detection is over; when the accumulated abnormality value doesn't reach the threshold value, increasing a sequence number i of the time range ti by 1;
Step 5): when a value of the sequence number i is smaller than or equals n, returning to step 3);
and when the value of the sequence number iI is bigger than n, entering next detection cycle.
To ease illustration, the technical terms in the foregoing description are shown by symbols, and concrete meanings of the symbols will be given in the following paragraphs in conjunction with the technical solution:
T is a detection cycle.
.................................................. The detection cycle T is divided into n time ranges ti (ti, t2 tn); and ti is any of the time ranges.
The detection cycle T can be determined by the user based on current application conditions and demands. Those skilled in the art can choose an appropriate value according to actual situations, to reflect the status of the SCR urea inject device, and identify failures with high accuracy and efficiency, which will be acceptable if no abnormality is missed or wrongly detected.
6 Date Recue/Date Received 2022-01-06 P is a pressure value of the urea solution in the outlet ducts 3.
Draw a box plot for pressure values of the urea solution corresponding to each of the time ranges ti, a maximum pressure value of the urea solution in the outlet ducts 3 in the present time range ti is shown as PmAx, a minimum pressure value is shown as PMIN, with the PmAx and PMIN, an upper quartile Pi, a median P2 and a lower quartile P3 (in the technical solution of the present invention only the upper quartile Pi and the lower quartile P3 in the box plot specifications will be used); calculate a difference between the upper quartile Pi and the lower quartile P3 as a quartile deviation AP i (Pi ¨P3= APi) of the present time range ti;
Calculate in advance in a laboratory by analogue analysis to obtain a standard quartile deviation of the present detection cycle (shown as APO); for example, use the pressure values of the urea solution in the outlet ducts 3 as a source of judging data, experiment with a new SCR system in good condition, extract data of the pressure values P of the urea solution in real time, draft box plots according to subdivisions in the detection cycle T, extract specifications to calculate quartile deviations, and calculate from multiple standard data an average value of the quartile deviations, which is the standard quartile deviation APO.
Similarly, the threshold value C. of the accumulated abnormality value, also called a warning count, is also obtained by analogue analysis in the laboratory.
Compare the calculated quartile deviation AP i of the present time range ti with the standard quartile deviation APO obtained in advance, in case the quartile deviation AP
i is bigger than the standard quartile deviation APO, increase the accumulated abnormality value (shown as C) by 1, otherwise, don't increase the accumulated abnormality value C; that is, when in the present time range ti, APi > APO, C= C+ 1; otherwise, C doesn't increase, C= C+ 0. In other words, when in the present time range ti, APi APO, C doesn't increase, C= C+ 0; otherwise, C=
C+ 1.
When the accumulated abnormality value reaches the threshold value (a warning count Cmax), the controller will send a failure warning to the system, the detection is over; when the accumulated abnormality value doesn't reach the threshold value, the sequence number i of the
Draw a box plot for pressure values of the urea solution corresponding to each of the time ranges ti, a maximum pressure value of the urea solution in the outlet ducts 3 in the present time range ti is shown as PmAx, a minimum pressure value is shown as PMIN, with the PmAx and PMIN, an upper quartile Pi, a median P2 and a lower quartile P3 (in the technical solution of the present invention only the upper quartile Pi and the lower quartile P3 in the box plot specifications will be used); calculate a difference between the upper quartile Pi and the lower quartile P3 as a quartile deviation AP i (Pi ¨P3= APi) of the present time range ti;
Calculate in advance in a laboratory by analogue analysis to obtain a standard quartile deviation of the present detection cycle (shown as APO); for example, use the pressure values of the urea solution in the outlet ducts 3 as a source of judging data, experiment with a new SCR system in good condition, extract data of the pressure values P of the urea solution in real time, draft box plots according to subdivisions in the detection cycle T, extract specifications to calculate quartile deviations, and calculate from multiple standard data an average value of the quartile deviations, which is the standard quartile deviation APO.
Similarly, the threshold value C. of the accumulated abnormality value, also called a warning count, is also obtained by analogue analysis in the laboratory.
Compare the calculated quartile deviation AP i of the present time range ti with the standard quartile deviation APO obtained in advance, in case the quartile deviation AP
i is bigger than the standard quartile deviation APO, increase the accumulated abnormality value (shown as C) by 1, otherwise, don't increase the accumulated abnormality value C; that is, when in the present time range ti, APi > APO, C= C+ 1; otherwise, C doesn't increase, C= C+ 0. In other words, when in the present time range ti, APi APO, C doesn't increase, C= C+ 0; otherwise, C=
C+ 1.
When the accumulated abnormality value reaches the threshold value (a warning count Cmax), the controller will send a failure warning to the system, the detection is over; when the accumulated abnormality value doesn't reach the threshold value, the sequence number i of the
7 Date Recue/Date Received 2022-01-06 present time range ti increases by 1 (i= i + 1).
When the sequence number i is smaller than or equals n, return to step 3), that is, to continue analysis and judging of the next time range; when the sequence number i is bigger than n, the whole detection cycle is over, and the accumulated abnormality value throughout the detection cycle T is smaller than the threshold value CmAx, return to step 2), continue next detection cycle, and the accumulated abnormality value is reset to be zero (that is, zero clearing C).
Embodiment 1 Targeting at a urea inject device of a SCR system of a diesel vehicle, diagnose failure during injection stage:
.. As shown in figure 1:
Si: acquiring in real time pressure values P of the urea solution in the outlet ducts of the device;
S2: defining a detection cycle T=ls, setting the detection cycle T to be n( n=100) time ranges ti ti t2 .. Two) chronologically, a length of each of the time ranges is 10ms;
Set an initial accumulated abnormality value C to be zero (C=0);
.. By analogue analysis, the standard quartile deviation APO is determined to be 35kpa, and the threshold value of the accumulated abnormality value is Cmax = 3;
S3: drawing a box plot for pressure values of urea solution corresponding to the time range ti in turn, extracting the upper quartile Pi and the lower quartile P3, calculating a quartile deviation AP i for the current time range ti and comparing AP i with the standard quartile deviation APO =
35kpa;
As shown in figure 1, when APi APO, everything is normal, the accumulated abnormality value C doesn't increase, C= C+ 0;
As shown in figure 1, when AP i > APO (that is, APi APO is judged to be false), something abnormal happens, the accumulated abnormality value increases by 1, C= C + 1;
When the sequence number i is smaller than or equals n, return to step 3), that is, to continue analysis and judging of the next time range; when the sequence number i is bigger than n, the whole detection cycle is over, and the accumulated abnormality value throughout the detection cycle T is smaller than the threshold value CmAx, return to step 2), continue next detection cycle, and the accumulated abnormality value is reset to be zero (that is, zero clearing C).
Embodiment 1 Targeting at a urea inject device of a SCR system of a diesel vehicle, diagnose failure during injection stage:
.. As shown in figure 1:
Si: acquiring in real time pressure values P of the urea solution in the outlet ducts of the device;
S2: defining a detection cycle T=ls, setting the detection cycle T to be n( n=100) time ranges ti ti t2 .. Two) chronologically, a length of each of the time ranges is 10ms;
Set an initial accumulated abnormality value C to be zero (C=0);
.. By analogue analysis, the standard quartile deviation APO is determined to be 35kpa, and the threshold value of the accumulated abnormality value is Cmax = 3;
S3: drawing a box plot for pressure values of urea solution corresponding to the time range ti in turn, extracting the upper quartile Pi and the lower quartile P3, calculating a quartile deviation AP i for the current time range ti and comparing AP i with the standard quartile deviation APO =
35kpa;
As shown in figure 1, when APi APO, everything is normal, the accumulated abnormality value C doesn't increase, C= C+ 0;
As shown in figure 1, when AP i > APO (that is, APi APO is judged to be false), something abnormal happens, the accumulated abnormality value increases by 1, C= C + 1;
8 Date Recue/Date Received 2022-01-06 For example, as shown in figure 3, the box plot for the first time range ti, where it can be seen that a difference between the upper quartile Pi and the lower quartile P3 is not bigger than 20kpa, that is, APi < APO = 35kpa, which reflects data for a normal condition, the accumulated abnormality value C doesn't increase, and remains the initial value 0, For example, see figure 4, the box plot for the 39th time range t39, where it can be seen that, a difference between the upper quartile Pi and the lower quartile P3 is 100kpa, that is, AP i > APO
=35kpa; which reflects data for an abnormal condition, the accumulated abnormality value C
increases by 1, C=C+1;
S4: when the accumulated abnormality value C doesn't reach the threshold value, the sequence .. number i of the time range ti increases by 1, that is, i = i +1; when the accumulated abnormality value C reaches the threshold value, send a failure warning, the detection is over;
S5: when the sequence number i is smaller than or equals n, return to step 3);
when the sequence number i is bigger than n, return to step 3) to enter next detection cycle.
For example, when the accumulated abnormality value C =3, reaches the threshold value C.
.. after inspecting the 69th time range in sequence, the controller 7 sends a failure warning, for example, reminding the driver fluctuation of pressure values of the urea solution of the SCR
system is big, there is something wrong; the detection is over;
For example, in another embodiment, when during the entire detection cycle T
after inspecting the time range ti until the time range tioo, the accumulated abnormality value C is smaller than .. the threshold value C., the sequence number i increases by 1, the sequence number i = 101; as the sequence number i = 101, bigger than n (100), go to step 2) to start next detection cycle, and the accumulated abnormality value is reset to be zero.
It should be understood that although this specification is described in accordance with the embodiments, not each embodiment only includes an independent technical solution. This narration in the specification is only for the sake of clarity, and those skilled in the art should regard the specification as a whole. The technical solutions in the embodiments can also be
=35kpa; which reflects data for an abnormal condition, the accumulated abnormality value C
increases by 1, C=C+1;
S4: when the accumulated abnormality value C doesn't reach the threshold value, the sequence .. number i of the time range ti increases by 1, that is, i = i +1; when the accumulated abnormality value C reaches the threshold value, send a failure warning, the detection is over;
S5: when the sequence number i is smaller than or equals n, return to step 3);
when the sequence number i is bigger than n, return to step 3) to enter next detection cycle.
For example, when the accumulated abnormality value C =3, reaches the threshold value C.
.. after inspecting the 69th time range in sequence, the controller 7 sends a failure warning, for example, reminding the driver fluctuation of pressure values of the urea solution of the SCR
system is big, there is something wrong; the detection is over;
For example, in another embodiment, when during the entire detection cycle T
after inspecting the time range ti until the time range tioo, the accumulated abnormality value C is smaller than .. the threshold value C., the sequence number i increases by 1, the sequence number i = 101; as the sequence number i = 101, bigger than n (100), go to step 2) to start next detection cycle, and the accumulated abnormality value is reset to be zero.
It should be understood that although this specification is described in accordance with the embodiments, not each embodiment only includes an independent technical solution. This narration in the specification is only for the sake of clarity, and those skilled in the art should regard the specification as a whole. The technical solutions in the embodiments can also be
9 Date Recue/Date Received 2022-01-06 appropriately combined to form other embodiments that can be understood by those skilled in the art.
The series of detailed descriptions listed above are only specific descriptions of feasible implementations of the present invention. They are not intended to limit the scope of protection of the present invention. Any equivalent embodiments or modifications made without departing from the technical spirit of the present invention shall be included in the protection scope of the present invention.
Date Recue/Date Received 2022-01-06
The series of detailed descriptions listed above are only specific descriptions of feasible implementations of the present invention. They are not intended to limit the scope of protection of the present invention. Any equivalent embodiments or modifications made without departing from the technical spirit of the present invention shall be included in the protection scope of the present invention.
Date Recue/Date Received 2022-01-06
Claims (3)
1. A failure detection method for SCR urea injection devices, wherein:
The failure detection method is provided for use during an injection stage of an SCR urea injection device, and comprises following steps:
Step 1): acquiring on a real time basis pressure values of urea solution in outlet ducts of the SCR urea injection device;
Step 2): defining a detection cycle T, dividing chronologically the detection cycle T into n time ranges L tn); setting an accumulated abnormality value at an initial point of the detection cycle T to be zero;
Step 3): drawing a box plot for urea solution pressure values corresponding to the time range L in turn, analyzing the box plot, and judging whether there is any abnormality in the time range L; when there is an abnormality, increasing the accumulated abnormality value by 1, otherwise don't increase the accumulated abnormality value;
In step 3), a way to judge the abnormality is: to obtain corresponding upper quartile and lower quartile according to a biggest pressure value and a smallest pressure value, calculate a difference between the upper quartile and the lower quartile, which is counted as a quartile deviation of the time range; comparing the quartile deviation of the time range with a standard quartile deviation measured in advance, and when the quartile deviation is bigger than the standard quartile deviation, it is judged that the abnormality occurs;
Step 4): when the accumulated abnormality value reaches a threshold value, sending a failure warning, detection is over; when the accumulated abnormality value doesn't reach the threshold value, increasing a sequence number of the time range L by one; and Step 5): when a value of the sequence number i is smaller than or equals n, returning to step 3);
when the value of the sequence number I is bigger than n, returning to step 2) to start another detection cycle.
The failure detection method is provided for use during an injection stage of an SCR urea injection device, and comprises following steps:
Step 1): acquiring on a real time basis pressure values of urea solution in outlet ducts of the SCR urea injection device;
Step 2): defining a detection cycle T, dividing chronologically the detection cycle T into n time ranges L tn); setting an accumulated abnormality value at an initial point of the detection cycle T to be zero;
Step 3): drawing a box plot for urea solution pressure values corresponding to the time range L in turn, analyzing the box plot, and judging whether there is any abnormality in the time range L; when there is an abnormality, increasing the accumulated abnormality value by 1, otherwise don't increase the accumulated abnormality value;
In step 3), a way to judge the abnormality is: to obtain corresponding upper quartile and lower quartile according to a biggest pressure value and a smallest pressure value, calculate a difference between the upper quartile and the lower quartile, which is counted as a quartile deviation of the time range; comparing the quartile deviation of the time range with a standard quartile deviation measured in advance, and when the quartile deviation is bigger than the standard quartile deviation, it is judged that the abnormality occurs;
Step 4): when the accumulated abnormality value reaches a threshold value, sending a failure warning, detection is over; when the accumulated abnormality value doesn't reach the threshold value, increasing a sequence number of the time range L by one; and Step 5): when a value of the sequence number i is smaller than or equals n, returning to step 3);
when the value of the sequence number I is bigger than n, returning to step 2) to start another detection cycle.
2. The failure detection method for SCR urea injection devices according to claim 1, wherein:
a value of the standard quartile deviation and a value of the threshold value have been got in advance by analogue analysis in a laboratory.
a value of the standard quartile deviation and a value of the threshold value have been got in advance by analogue analysis in a laboratory.
3. The failure detection method for SCR urea injection devices according to claim 1, wherein:
in step 1), obtaining in real time the pressure values of the urea solution in the outlet ducts of the SCR urea injection device is done by providing a pressure sensor on the outlet ducts of the SCR urea injection device.
in step 1), obtaining in real time the pressure values of the urea solution in the outlet ducts of the SCR urea injection device is done by providing a pressure sensor on the outlet ducts of the SCR urea injection device.
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| CN202010945468.3 | 2020-09-10 | ||
| CN202010945468.3A CN112031903B (en) | 2020-09-10 | 2020-09-10 | Fault diagnosis method for SCR urea injection device |
| PCT/CN2021/081603 WO2021213093A1 (en) | 2020-09-10 | 2021-03-18 | Fault diagnosis method for scr urea injection apparatus |
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| CN (1) | CN112031903B (en) |
| AU (1) | AU2021236547A1 (en) |
| CA (1) | CA3131581A1 (en) |
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| CN114673581A (en) * | 2022-03-22 | 2022-06-28 | 潍柴动力股份有限公司 | Method and device for determining whether urea pump is in maintenance waiting state |
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| CN112031903B (en) * | 2020-09-10 | 2021-04-02 | 上海星融汽车科技有限公司 | Fault diagnosis method for SCR urea injection device |
| CN114251165B (en) * | 2021-12-08 | 2023-03-21 | 潍柴动力股份有限公司 | Pressure pipe power detection method and device, storage medium and vehicle |
| CN114607494A (en) * | 2022-03-04 | 2022-06-10 | 潍柴动力股份有限公司 | Method and device for monitoring faults of heating electromagnetic valve of urea box |
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| WO2005073528A1 (en) * | 2004-02-02 | 2005-08-11 | Nissan Diesel Motor Co., Ltd. | Device for purifying exhaust gas of engine |
| JP4906525B2 (en) * | 2007-01-26 | 2012-03-28 | ボッシュ株式会社 | Clogging determination device for reducing agent injection valve and clogging determination method for reducing agent injection valve |
| JP4840703B2 (en) * | 2007-11-16 | 2011-12-21 | トヨタ自動車株式会社 | Abnormality diagnosis device for exhaust purification system |
| KR100907363B1 (en) * | 2008-03-03 | 2009-07-10 | 현대자동차주식회사 | Method for controlling urea-scr system |
| JP5534602B2 (en) * | 2009-11-06 | 2014-07-02 | ボッシュ株式会社 | Abnormality detection device and abnormality detection method for reducing agent injection valve |
| JP6508475B2 (en) * | 2015-10-27 | 2019-05-08 | 株式会社デンソー | Diagnostic device |
| CN107120164A (en) * | 2016-02-24 | 2017-09-01 | 罗伯特·博世有限公司 | The method for diagnosing faults and device of the injector of vehicle SCR systems |
| WO2017211425A1 (en) * | 2016-06-09 | 2017-12-14 | Plastic Omnium Advanced Innovation And Research | Method for detecting a leak in a feed line of a scr system |
| CN106227640B (en) * | 2016-07-27 | 2019-03-19 | 北京市环境保护监测中心 | A kind of abnormal deviation data examination method and system based on automatic monitor |
| JPWO2018047554A1 (en) * | 2016-09-12 | 2019-04-18 | ボッシュ株式会社 | Control device |
| CN107044322B (en) * | 2016-12-26 | 2019-09-27 | 潍柴动力股份有限公司 | A kind of urea nozzle blocks the control method of removing and judgement nozzle damage |
| CN109681304A (en) * | 2018-12-25 | 2019-04-26 | 上海星融汽车科技有限公司 | A kind of SCR system urea nozzle blocking recognition methods |
| CN112031903B (en) * | 2020-09-10 | 2021-04-02 | 上海星融汽车科技有限公司 | Fault diagnosis method for SCR urea injection device |
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2020
- 2020-09-10 CN CN202010945468.3A patent/CN112031903B/en active Active
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- 2021-03-18 AU AU2021236547A patent/AU2021236547A1/en not_active Abandoned
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| CN114673581A (en) * | 2022-03-22 | 2022-06-28 | 潍柴动力股份有限公司 | Method and device for determining whether urea pump is in maintenance waiting state |
| CN114673581B (en) * | 2022-03-22 | 2023-01-24 | 潍柴动力股份有限公司 | Method and device for determining whether urea pump is in maintenance waiting state |
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| CN112031903B (en) | 2021-04-02 |
| AU2021236547A1 (en) | 2022-03-24 |
| WO2021213093A1 (en) | 2021-10-28 |
| CN112031903A (en) | 2020-12-04 |
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