CN114087055B - Engine aftertreatment system gas leakage diagnosis method and engine aftertreatment system - Google Patents
Engine aftertreatment system gas leakage diagnosis method and engine aftertreatment system Download PDFInfo
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- CN114087055B CN114087055B CN202010863951.7A CN202010863951A CN114087055B CN 114087055 B CN114087055 B CN 114087055B CN 202010863951 A CN202010863951 A CN 202010863951A CN 114087055 B CN114087055 B CN 114087055B
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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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- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
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- Y02T10/10—Internal combustion engine [ICE] based vehicles
- Y02T10/40—Engine management systems
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Abstract
The invention provides a gas leakage diagnosis method of an engine aftertreatment system and the engine aftertreatment system, which solve the problem that the traditional aftertreatment system can only perform leakage inspection under the static condition and cannot monitor gas leakage in real time. The air leakage diagnosis method comprises the following steps: judging whether the engine state data is in a preset range or not; if yes, obtaining an aftertreatment system pressure drop error based on the standard aftertreatment pressure drop, the engine exhaust back pressure and the aftertreatment system pressure; and comparing the pressure drop error of the aftertreatment system with the pressure drop limit value of the aftertreatment system, and diagnosing the air leakage condition of the aftertreatment system. By the method, the leakage condition of the aftertreatment system can be monitored in real time, and the false diagnosis of urea crystallization and related faults caused by air leakage is effectively solved; and the development cost can be effectively reduced without changing the existing hardware or adding new hardware.
Description
Technical Field
The invention relates to the technical field of engines, in particular to an air leakage diagnosis method of an engine aftertreatment system and the engine aftertreatment system.
Background
In order to meet the emission limit required by the national six-emission regulations and the related diagnostic requirements of the aftertreatment system, diesel engine enterprises at home and abroad commonly adopt a DOC+DPF+SCR (DOC: diesel Oxidation Catalyst, oxidation catalytic converter; DPF: diesel Particulate Filter, diesel particulate filter; SCR: selective Catalytic Reduction, selective catalytic reduction technology) aftertreatment technical route, and the aftertreatment system needs to have very high NO according to the requirements of the regulations X (Nitrogen oxide) conversion efficiency and harsh aftertreatment system operating condition diagnostic schemes, aftertreatment system and pipeline leaks thereof can cause urea crystallization to result in NO X Conversion efficiency is reduced and related diagnostic false alarms, so that the tightness of the aftertreatment system and its piping must be ensured. The traditional air leakage detection of the aftertreatment system generally adopts a static pressure maintaining leakage detection or soapy water spraying method, and the method can only detect under the static condition of the engine, can not monitor air leakage in real time, and even if the air leakage existsThere are cases where the injection of the urea system and the fault diagnosis associated with the blow-by cannot be adjusted in time.
Disclosure of Invention
In view of the above, the embodiment of the invention provides a method for diagnosing air leakage of an engine aftertreatment system and the engine aftertreatment system, which solve the problem that the traditional aftertreatment system can only perform leakage inspection under a static condition and cannot monitor the air leakage in real time.
An embodiment of the invention provides a method for diagnosing air leakage of an engine aftertreatment system and the engine aftertreatment system, comprising the following steps: judging whether the engine state data is in a preset range or not; if yes, obtaining an aftertreatment system pressure drop error based on the standard aftertreatment pressure drop, the engine exhaust back pressure and the aftertreatment system pressure; and diagnosing the air leakage condition of the aftertreatment system based on the pressure drop error of the aftertreatment system and the pressure drop limit value of the aftertreatment system.
In one embodiment, the engine state data includes: engine speed, rate of change of engine speed, engine torque, rate of change of engine torque, exhaust back pressure, rate of change of exhaust back pressure, combustion state of the engine; wherein the determining whether the engine state data is within a preset range includes: the engine speed is within a preset range, the rate of change of the engine speed is within a preset range, the engine torque is within a preset range, the rate of change of the engine torque is within a preset range, the exhaust back pressure is within a preset range, the rate of change of the exhaust back pressure is within a preset range, and the combustion state of the engine is in a non-thermally managed state.
In one embodiment, the aftertreatment system pressure drop error includes one of the following errors: a first error, a second error, and an average error; the method comprises the steps of obtaining a first error of the pressure drop of the aftertreatment system based on the pressure drop of the first standard aftertreatment system and the actual pressure drop of the aftertreatment system; obtaining a second error of the aftertreatment system pressure drop based on a second standard aftertreatment system pressure drop and the actual aftertreatment system pressure drop; and weighting the first error and the second error to obtain the average pressure drop error of the post-processing system.
In one embodiment, the actual aftertreatment system pressure drop is derived based on the engine exhaust back pressure and the aftertreatment system pressure.
In one embodiment, the first standard aftertreatment system pressure drop is calculated by fitting an engine speed, an engine torque, an exhaust temperature, an exhaust flow, an exhaust back pressure, an intake flow, an injection quantity, an ambient temperature, and an ambient pressure.
In one embodiment, the fitting calculation method is as follows: f (x) =a 0 +(a 1 b 1 +a 2 b 2 +a 3 +a 4 +a 5 +a 6 b 3 )*a 7 *a 8 The method comprises the steps of carrying out a first treatment on the surface of the Wherein a is 0 Is a constant term, a 1 A is the engine speed, a 2 For engine torque, a 3 For the exhaust temperature, a 4 For exhaust flow, a 5 For exhaust back pressure, a 6 A is the sum of the intake air flow and the fuel injection amount 7 At ambient temperature, a 8 Is at ambient pressure.
In one embodiment, the second aftertreatment system pressure drop is derived based on engine speed and engine torque.
In one embodiment, diagnosing an air leakage condition of the aftertreatment system based on the aftertreatment system pressure drop error and an aftertreatment system pressure drop limit includes: and triggering a meter marking bit when the post-processing system pressure drop error exceeds the post-processing system pressure drop limit value.
An engine aftertreatment system comprising: the judging module is configured to judge whether the engine state data is in a preset range or not; the data acquisition module is configured to acquire engine state data, engine exhaust back pressure and engine aftertreatment system pressure; a computing module configured to: calculating to obtain a pressure drop error of the aftertreatment system according to the exhaust back pressure of the engine, the pressure of the aftertreatment system and the pressure drop of the standard aftertreatment system; and calculating based on the pressure drop error of the aftertreatment system and the pressure drop limit value of the aftertreatment system, and diagnosing the air leakage condition of the aftertreatment system.
In one embodiment, the data acquisition module is further configured to: collecting the engine state data, wherein the engine state data comprises: engine speed, rate of change of engine speed, engine torque, rate of change of engine torque, exhaust back pressure, rate of change of exhaust back pressure, combustion state of the engine;
the determination module is further configured to: judging that the engine speed is within a preset range, judging that the change rate of the engine speed is within a preset range, judging that the engine torque is within a preset range, judging that the change rate of the engine torque is within a preset range, judging that the exhaust back pressure is within a preset range, judging that the change rate of the exhaust back pressure is within a preset range, and judging that the combustion state of the engine should be in a state of non-thermal management.
In one embodiment, the computing module is further configured to: calculating the pressure drop of the first standard aftertreatment system and the pressure drop of the actual aftertreatment system to obtain a first error of the pressure drop of the aftertreatment system; and/or calculating the pressure drop of the second standard aftertreatment system and the pressure drop of the actual aftertreatment system to obtain a second error of the pressure drop of the aftertreatment system; and weighting the first error and the second error to obtain the average pressure drop error of the post-processing system.
In one embodiment, the computing module is further configured to: the actual aftertreatment system pressure drop is derived based on the engine exhaust back pressure, the aftertreatment system pressure.
In one embodiment, the data acquisition module is further configured to: collecting engine speed, engine torque, exhaust temperature, exhaust flow, exhaust back pressure, intake flow, fuel injection quantity, ambient temperature and ambient pressure; the computing module is further configured to: and fitting and calculating the engine speed, the engine torque, the exhaust temperature, the exhaust flow, the exhaust back pressure, the air inlet flow, the oil injection quantity, the ambient temperature and the ambient pressure to obtain the pressure drop of the first aftertreatment system.
In one embodiment, the system further comprises a query module configured to: a second aftertreatment system pressure drop is derived based on the engine speed and the engine torque query.
The embodiment of the invention provides a gas leakage diagnosis method of an engine aftertreatment system and the engine aftertreatment system, wherein the gas leakage diagnosis method comprises the following steps: judging whether the engine state data is in a preset range or not; if yes, obtaining an aftertreatment system pressure drop error based on the standard aftertreatment pressure drop, the engine exhaust back pressure and the aftertreatment system pressure; and comparing the pressure drop error of the aftertreatment system with the pressure drop limit value of the aftertreatment system, and diagnosing the air leakage condition of the aftertreatment system. By the method, the leakage condition of the post-treatment system can be diagnosed, so that the leakage condition of the post-treatment system can be monitored in real time, and the false diagnosis of urea crystallization and related faults caused by the leakage is effectively solved; and the development cost can be effectively reduced without changing the existing hardware or adding new hardware.
Drawings
Fig. 1 is a schematic flow chart of an air leakage diagnosis method of an engine aftertreatment system according to an embodiment of the present invention.
Fig. 2 is a schematic diagram illustrating an air leakage diagnosis method of an engine aftertreatment system according to another embodiment of the present invention.
Fig. 3 is a flowchart illustrating a method for calculating a pressure drop error of a post-processing system according to an embodiment of the invention.
Fig. 4 is a schematic block diagram of a post-processing system according to an embodiment of the invention.
Fig. 5 is a schematic structural diagram of an engine aftertreatment device according to an embodiment of the present invention.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Fig. 1 is a schematic flow chart of an air leakage diagnosis method of an engine aftertreatment system according to an embodiment of the present invention. Fig. 2 is a schematic diagram illustrating an air leakage diagnosis method of an engine aftertreatment system according to another embodiment of the present invention.
As shown in fig. 1-2, the air leakage diagnosis method of the engine aftertreatment system includes:
and 001, judging whether the engine state data is in a preset range. Wherein the engine state data includes: engine speed, rate of change of engine speed, engine torque, rate of change of engine torque, exhaust back pressure, rate of change of exhaust back pressure, combustion state of the engine. Judging that the engine state data is in a preset range to simultaneously meet the conditions that the engine speed is in a preset range, the change rate of the engine speed is in a preset range, the engine torque is in a preset range, the change rate of the engine torque is in a preset range, the exhaust back pressure is in a preset range, the change rate of the exhaust back pressure is in a preset range, and the combustion state of the engine is in a non-thermal management state, wherein the non-thermal management state refers to hardware intervention work such as ETV (exhaust throttle valve) or IAT (air inlet throttle valve) which is related to no thermal management. When any one or more of the engine speed, the rate of change of the engine speed, the engine torque, the rate of change of the engine torque, the exhaust back pressure, the rate of change of the exhaust back pressure, and the combustion state of the engine are not within a preset range, it is determined that the engine state data is not within the preset range. And when the engine state data is judged to be within the preset range, carrying out the subsequent method steps, and when the engine state data is judged to be not within the preset range, not carrying out the subsequent method steps. The judgment standard is set to meet the condition that all the state data are in a preset range at the same time, so that the engine is in a relatively stable state during diagnosis, and diagnosis is performed when the engine is in the relatively stable state, and the robustness of the diagnosis of the aftertreatment system can be improved.
It is understood that the preset range of the engine state data may be calibrated differently according to different engine models, and the preset range of the engine state data may be selected.
And 002, obtaining the pressure drop error of the aftertreatment system based on the standard pressure drop of the aftertreatment system, the exhaust back pressure of the engine and the pressure of the aftertreatment system if the engine state data is judged to be in the preset range. And calculating according to the exhaust back pressure of the engine and the pressure of the aftertreatment system to obtain the actual pressure drop of the aftertreatment system. Alternatively, the engine exhaust back pressure may be subtracted from the aftertreatment system pressure to obtain the actual aftertreatment system pressure drop. Exhaust back pressure and aftertreatment system pressure of the engine may be monitored by sensors. And comparing the standard post-treatment system pressure drop with the actual post-treatment system pressure drop to obtain the post-treatment system pressure drop error. The standard aftertreatment system pressure drop may be subtracted from the actual aftertreatment system pressure drop to obtain an aftertreatment system pressure drop error. The standard aftertreatment system pressure drop may include at least one of a first standard aftertreatment system pressure drop and a second standard aftertreatment system pressure drop. The first standard aftertreatment system pressure drop is obtained by fitting and calculating the engine speed, the engine torque, the exhaust temperature, the exhaust flow, the exhaust back pressure, the intake flow, the fuel injection quantity, the ambient temperature and the ambient pressure. Alternatively, the fitting calculation method is f (x) =a 0 +(a 1 b 1 +a 2 b 2 +a 3 +a 4 +a 5 +a 6 b 3 )*a 7 *a 8 The method comprises the steps of carrying out a first treatment on the surface of the Wherein a is 0 Is a constant term, a 1 A is the engine speed, a 2 For engine torque, a 3 For the exhaust temperature, a 4 For exhaust flow, a 5 For exhaust back pressure, a 6 A is the sum of the intake air flow and the fuel injection amount 7 At ambient temperature, a 8 Is at ambient pressure. The second standard aftertreatment system pressure drop is based on an engine speed and an engine torque look-up table (specifically shown in table one). The first standard post-treatment system pressure drop and the actual post-treatment system pressure drop can be subtracted to obtain a post-treatment system pressure drop first error, and the post-treatment system pressure drop first error is the post-treatment system pressure drop error. Or the second standard post-treatment system pressure drop can be subtracted from the actual post-treatment system pressure drop to obtain a post-treatment system pressure drop second error, wherein the post-treatment systemThe second error of the system pressure drop is the pressure drop error of the post-treatment system. Step 0031, again or as shown in FIG. 3: the first standard post-treatment system pressure drop and the actual post-treatment system pressure drop can be subtracted to obtain a first post-treatment system pressure drop error, step 0032, the second standard post-treatment system pressure drop and the actual post-treatment system pressure drop are subtracted to obtain a second post-treatment system pressure drop error, step 0033, the first error and the second error are weighted (added to obtain an average post-treatment system pressure drop error, and the average post-treatment system pressure drop error is the post-treatment system pressure drop error. The first error and the second error can be mutually complemented by weighting calculation to obtain the average error of the pressure drop of the post-processing system, so that the robustness of the diagnosis of the post-processing system can be improved.
Table one:
and step 003, comparing the pressure drop error of the aftertreatment system with the pressure drop limit value of the aftertreatment system, and diagnosing the air leakage condition of the aftertreatment system. When the pressure drop error of the post-treatment system is 0, judging that no air leakage exists; when the pressure drop error of the post-treatment system is not 0 and does not exceed the pressure drop limit of the post-treatment system, judging that the post-treatment system leaks air, and displaying no mark position on the instrument; when the voltage drop error of the post-processing system is not 0 and exceeds the voltage drop limit value of the post-processing system, the corresponding marking position of the display instrument is triggered to remind a worker to repair and check the post-processing system as soon as possible.
By the method, the leakage condition of the post-treatment system can be diagnosed, so that the leakage condition of the post-treatment system can be monitored in real time, and the false diagnosis of urea crystallization and related faults caused by the leakage is effectively solved; the robustness of system diagnosis is improved by adopting a polynomial or table lookup or a method combining the polynomial and the table lookup; the existing hardware is not required to be changed, new hardware is not required to be added, and development cost can be effectively reduced.
Fig. 4 is a schematic block diagram of a post-processing system according to an embodiment of the invention.
As shown in fig. 4, the engine aftertreatment system 100 includes: a judging module 02 and a calculating module 03. The determination module 02 is configured to determine whether the engine state data is within a preset range. The data acquisition module 01 is configured to acquire engine exhaust back pressure and engine aftertreatment system pressure. A calculation module 03 configured to: calculating according to the exhaust back pressure of the engine and the pressure of the aftertreatment system to obtain the pressure drop of the actual aftertreatment system; comparing the pressure drop of the standard aftertreatment system with the pressure drop of the actual aftertreatment system to obtain an aftertreatment system pressure drop error; and comparing the pressure drop error with the air leakage limit value of the aftertreatment system, and diagnosing the air leakage condition of the aftertreatment system. The data acquisition module 01 acquires the engine state data and sends the engine state data to the judgment module 02, the judgment module 02 judges whether the engine state data is in a preset range, and if the judgment module 02 judges that the engine state data is in the preset range, the data acquisition module 01 is informed; the data acquisition module 01 acquires the engine exhaust back pressure and the engine aftertreatment system pressure, and then the data acquisition module 01 sends the engine exhaust back pressure and the engine aftertreatment system pressure to the calculation module 03; the calculation module 03 calculates the actual aftertreatment system pressure according to the engine exhaust back pressure and the engine aftertreatment system pressure, then subtracts the absolute value of the standard aftertreatment system pressure drop and the actual aftertreatment system pressure drop to obtain an aftertreatment system pressure drop error, compares the aftertreatment system pressure drop error with the aftertreatment system pressure drop limit value, and diagnoses the air leakage condition of the aftertreatment system.
In an embodiment of the present invention, the data acquisition module 01 is further configured to: collecting the engine state data, wherein the engine state data comprises: engine speed, rate of change of engine speed, engine torque, rate of change of engine torque, exhaust back pressure, rate of change of exhaust back pressure, combustion state of the engine; the judgment module 02 may be further configured to: judging that the engine speed is within a preset range, judging that the change rate of the engine speed is within a preset range, judging that the engine torque is within a preset range, judging that the change rate of the engine torque is within a preset range, judging that the exhaust back pressure is within a preset range, judging that the change rate of the exhaust back pressure is within a preset range, and judging that the combustion state of the engine should be in a state of non-thermal management. After the judging module 02 receives the data of the engine speed, the change rate of the engine speed, the engine torque, the change rate of the engine torque, the exhaust back pressure, the change rate of the exhaust back pressure and the combustion state of the engine, which are acquired by the data acquisition module 01, judging whether the data of the engine state is in a preset range, if the data of the engine state is in the preset range, monitoring the air leakage of the aftertreatment system, and if one or more data of the engine state is not in the preset range, not monitoring the air leakage of the aftertreatment system.
In an embodiment of the present invention, the calculation module 03 is further configured to: comparing the pressure drop of the first standard aftertreatment system with the pressure drop of the actual aftertreatment system to obtain a first error of the pressure drop of the aftertreatment system; and/or comparing the pressure drop of the second aftertreatment system with the calculated pressure drop of the actual aftertreatment system to obtain a second error of the pressure drop of the aftertreatment system; and weighting the first error and the second error to obtain the average pressure drop error of the post-processing system. After the calculation module 03 calculates the pressure drop of the actual aftertreatment system, subtracting the absolute value from the pressure drop of the first standard aftertreatment system and the pressure drop of the actual aftertreatment system to obtain a first error of the pressure drop of the aftertreatment system; and/or subtracting the absolute value from the second standard aftertreatment system pressure drop and the actual aftertreatment system pressure drop to obtain a second error of the aftertreatment system pressure drop; the first error can be calculated only, the second error can be calculated only, or both the first error and the second error are calculated, and when the first error is calculated only, the first error can be used as a pressure drop error of a post-processing system; when only the second error is calculated, the second error may be used as a post-processing system pressure drop error; when both the first error and the second error need to be calculated at the same time, the calculation module 03 also needs to add (weight) the first error and the second error to obtain an average error of the pressure drop of the post-processing system, and the average error of the pressure drop of the post-processing system can be used as the error of the pressure drop of the post-processing system.
In an embodiment of the present invention, the data acquisition module 01 is further configured to: the method comprises the steps of collecting engine speed, engine torque, exhaust temperature, exhaust flow, exhaust back pressure, intake air flow, fuel injection quantity, ambient temperature and ambient pressure. The calculation module 03 is further configured to: and fitting and calculating the engine speed, the engine torque, the exhaust temperature, the exhaust flow, the exhaust back pressure, the air inlet flow, the oil injection quantity, the ambient temperature and the ambient pressure to obtain the pressure drop of the first aftertreatment system. The data acquisition module 01 acquires the rotation speed of the engine, the torque of the engine, the exhaust temperature, the exhaust flow, the exhaust back pressure, the intake flow, the fuel injection quantity, the ambient temperature and the ambient pressure. The calculation module 03 is further configured to: and sending the values of the engine speed, the engine torque, the exhaust temperature, the exhaust flow, the exhaust back pressure, the air inlet flow, the fuel injection quantity, the ambient temperature and the ambient pressure to a calculation module 03, and carrying out fitting calculation on the values by the calculation module 03 to obtain the pressure drop of the first standard aftertreatment system.
The engine aftertreatment system 100 may also include a query module 04 configured to: and obtaining the pressure drop of the second aftertreatment system according to the engine speed and the engine torque table. The data acquisition module 01 acquires the engine speed and the engine torque and then sends the engine speed and the engine torque to the query module 04, and the query module 04 inquires the standard post-processing system pressure drop corresponding to the engine speed and the engine torque in the table, wherein the standard post-processing system pressure drop is the second standard post-processing system pressure drop.
By the engine aftertreatment system 100, the robustness of system diagnosis is improved by adopting a fitting calculation method, a table look-up method or a combination of the fitting calculation method and the table look-up method.
In an embodiment of the present invention, the calculation module 03 is further configured to: comparing the pressure drop error of the aftertreatment system with the pressure drop limit value of the aftertreatment system, and diagnosing the air leakage condition of the aftertreatment system; after the calculation module 03 calculates the pressure drop error of the post-processing system, the pressure drop error of the post-processing system is subtracted from the pressure drop limit value of the post-processing system, and if the difference between the pressure drop error of the post-processing system and the pressure drop limit value of the post-processing system is larger than a preset value, the instrument representation bit display is triggered.
Fig. 5 is a schematic structural diagram of an engine aftertreatment device according to an embodiment of the present invention.
As shown in fig. 5, the engine 1 aftertreatment device includes: an engine 1, an exhaust back pressure sensor 5, an aftertreatment system conduit 2, an aftertreatment system 3 and an aftertreatment system pressure sensor 4. Wherein the engine 1 comprises an exhaust manifold; an exhaust back pressure sensor 5 is mounted on the exhaust manifold for detecting the exhaust back pressure of the engine 1; one end of the post-treatment system pipeline 2 is connected with the exhaust manifold, and the other end of the post-treatment system pipeline is connected with the post-treatment system 3; and an aftertreatment system pressure sensor 4 mounted on the aftertreatment system for detecting aftertreatment system pressure. In addition, the post-processing device further comprises an instrument, when the difference between the pressure drop error of the post-processing system and the pressure drop limit value of the post-processing system is larger than a preset value, the instrument represents position display to remind a worker to maintain and check as soon as possible, so that the leakage condition of the post-processing system can be monitored in real time, and the crystallization of the post-processing system and the misdiagnosis of related fault codes caused by air leakage are reduced. And the development cost can be effectively reduced without changing the existing hardware or adding new hardware.
It is appreciated that the engine aftertreatment system 100 may be a diesel engine aftertreatment system. It will be further appreciated that in addition to the exhaust back pressure sensor 5 and the aftertreatment system pressure sensor 4 described above, the engine aftertreatment device may include other electronic components, such as electronics for measuring engine speed, electronics for measuring engine torque, electronics for monitoring engine combustion conditions, etc., and the present disclosure will not be repeated here.
The foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather is to be construed as including any modifications, equivalents, and alternatives falling within the spirit and principles of the invention.
Claims (9)
1. A method of diagnosing air leakage in an engine aftertreatment system, comprising:
judging whether the engine state data is in a preset range or not;
if yes, then
Performing fitting calculation on the engine speed, the engine torque, the exhaust temperature, the exhaust flow, the exhaust back pressure, the intake flow, the fuel injection quantity, the ambient temperature and the ambient pressure to obtain the pressure drop of the first standard aftertreatment system;
obtaining a second standard aftertreatment system pressure drop based on the engine speed and the engine torque;
obtaining a first error of the aftertreatment system pressure drop based on the first standard aftertreatment system pressure drop and the actual aftertreatment system pressure drop;
obtaining a second error of the aftertreatment system pressure drop based on a second standard aftertreatment system pressure drop and the actual aftertreatment system pressure drop;
weighting the first error and the second error to obtain a post-processing system pressure drop average error;
diagnosing the air leakage condition of the aftertreatment system based on the pressure drop error of the aftertreatment system and the pressure drop limit value of the aftertreatment system; wherein the aftertreatment system pressure drop error includes one of the first error, the second error, and the average error.
2. The method of diagnosing air leakage in an engine aftertreatment system according to claim 1, wherein the engine state data comprises: engine speed, rate of change of engine speed, engine torque, rate of change of engine torque, exhaust back pressure, rate of change of exhaust back pressure, combustion state of the engine;
wherein the determining whether the engine state data is within a preset range includes: the engine speed is within a preset range, the rate of change of the engine speed is within a preset range, the engine torque is within a preset range, the rate of change of the engine torque is within a preset range, the exhaust back pressure is within a preset range, the rate of change of the exhaust back pressure is within a preset range, and the combustion state of the engine is in a non-thermally managed state.
3. The method of diagnosing air leakage in an engine aftertreatment system according to claim 1 wherein the actual aftertreatment system pressure drop is derived based on the engine exhaust back pressure and the aftertreatment system pressure.
4. The air leakage diagnosis method of the engine aftertreatment system according to claim 1, wherein the fitting calculation method is as follows: f (x) =a 0 +(a 1 b 1 +a 2 b 2 +a 3 +a 4 +a 5 +a 6 b 3 )*a 7 *a 8 ；
Wherein a is 0 Is a constant term, a 1 A is the engine speed, a 2 For engine torque, a 3 For the exhaust temperature, a 4 For exhaust flow, a 5 For exhaust back pressure, a 6 A is the sum of the intake air flow and the fuel injection amount 7 At ambient temperature, a 8 Is at ambient pressure.
5. The method for diagnosing air leakage of an engine aftertreatment system according to claim 1 wherein diagnosing air leakage of the aftertreatment system based on the aftertreatment system pressure drop error and an aftertreatment system pressure drop limit comprises: and triggering a meter marking bit when the post-processing system pressure drop error exceeds the post-processing system pressure drop limit value.
6. An engine aftertreatment system, comprising:
the judging module is configured to judge whether the engine state data is in a preset range or not;
the data acquisition module is configured to acquire engine state data, engine exhaust back pressure and engine aftertreatment system pressure;
a query module configured to: obtaining a second aftertreatment system pressure drop based on the engine speed and the engine torque query;
a computing module configured to: performing fitting calculation on the engine speed, the engine torque, the exhaust temperature, the exhaust flow, the exhaust back pressure, the intake flow, the fuel injection quantity, the ambient temperature and the ambient pressure to obtain the pressure drop of the first standard aftertreatment system;
obtaining a first error of the aftertreatment system pressure drop based on the first standard aftertreatment system pressure drop and the actual aftertreatment system pressure drop;
obtaining a second error of the aftertreatment system pressure drop based on a second standard aftertreatment system pressure drop and the actual aftertreatment system pressure drop;
weighting the first error and the second error to obtain a post-processing system pressure drop average error;
calculating based on the pressure drop error of the aftertreatment system and the pressure drop limit value of the aftertreatment system, and diagnosing the air leakage condition of the aftertreatment system; wherein the aftertreatment system pressure drop error includes one of the first error, the second error, and the average error.
7. The engine aftertreatment system of claim 6, wherein the data acquisition module is further configured to: collecting the engine state data, wherein the engine state data comprises: engine speed, rate of change of engine speed, engine torque, rate of change of engine torque, exhaust back pressure, rate of change of exhaust back pressure, combustion state of the engine;
the determination module is further configured to: judging that the engine speed is within a preset range, judging that the change rate of the engine speed is within a preset range, judging that the engine torque is within a preset range, judging that the change rate of the engine torque is within a preset range, judging that the exhaust back pressure is within a preset range, judging that the change rate of the exhaust back pressure is within a preset range, and judging that the combustion state of the engine should be in a state of non-thermal management.
8. The engine aftertreatment system of claim 6, wherein the computing module is further configured to: the actual aftertreatment system pressure drop is derived based on the engine exhaust back pressure, the aftertreatment system pressure.
9. The engine aftertreatment system of claim 6, wherein the data acquisition module is further configured to: and collecting the engine speed, the engine torque, the exhaust temperature, the exhaust flow, the exhaust back pressure, the intake flow, the fuel injection quantity, the ambient temperature and the ambient pressure.
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| CN202010863951.7A CN114087055B (en) | 2020-08-25 | 2020-08-25 | Engine aftertreatment system gas leakage diagnosis method and engine aftertreatment system |
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| CN202010863951.7A CN114087055B (en) | 2020-08-25 | 2020-08-25 | Engine aftertreatment system gas leakage diagnosis method and engine aftertreatment system |
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| CN104314652A (en) * | 2014-08-15 | 2015-01-28 | 潍柴动力股份有限公司 | Detection method and detection device for damage to SCR (selective catalytic reduction) tank |
| CN106383013A (en) * | 2016-08-17 | 2017-02-08 | 潍柴动力股份有限公司 | Oil filter anti-counterfeiting and service life diagnosis system |
| CN110594019A (en) * | 2019-09-26 | 2019-12-20 | 潍柴动力股份有限公司 | Method and device for detecting exhaust and air leakage of engine |
| CN110725738A (en) * | 2019-12-17 | 2020-01-24 | 潍柴动力股份有限公司 | Method and device for detecting filtering capacity of DPF |
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| JP2008157200A (en) * | 2006-12-26 | 2008-07-10 | Mitsubishi Fuso Truck & Bus Corp | Abnormality detection device for exhaust emission control device |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN104314652A (en) * | 2014-08-15 | 2015-01-28 | 潍柴动力股份有限公司 | Detection method and detection device for damage to SCR (selective catalytic reduction) tank |
| CN106383013A (en) * | 2016-08-17 | 2017-02-08 | 潍柴动力股份有限公司 | Oil filter anti-counterfeiting and service life diagnosis system |
| CN110594019A (en) * | 2019-09-26 | 2019-12-20 | 潍柴动力股份有限公司 | Method and device for detecting exhaust and air leakage of engine |
| CN110725738A (en) * | 2019-12-17 | 2020-01-24 | 潍柴动力股份有限公司 | Method and device for detecting filtering capacity of DPF |
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