CN115075928B - Method for improving diagnostic robustness of urea injection system - Google Patents
Method for improving diagnostic robustness of urea injection system Download PDFInfo
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- CN115075928B CN115075928B CN202210854353.2A CN202210854353A CN115075928B CN 115075928 B CN115075928 B CN 115075928B CN 202210854353 A CN202210854353 A CN 202210854353A CN 115075928 B CN115075928 B CN 115075928B
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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
- 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
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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
- Y02T10/40—Engine management systems
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- Mechanical Engineering (AREA)
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- Exhaust Gas After Treatment (AREA)
Abstract
The application relates to a method for improving the diagnosis robustness of a urea injection system, which comprises the steps that in a urea pre-injection stage, a urea pressure sensor monitors the pressure of urea, the injection quantity of a urea pump in pre-injection is 500-20000g/h, the duration of urea pre-injection is more than 60s, the pressure of urea is less than 150kpa, and then the low-pressure fault of the urea in the pre-injection stage is diagnosed; in the urea injection stage, the urea pressure sensor always monitors the injection pressure of urea, and when the injection quantity is 500-10000g/h, the urea injection duration is more than 60s and the urea pressure is less than 150kpa, the low urea pressure fault in the injection stage is diagnosed. Therefore, the method for improving the diagnosis robustness of the urea injection system can diagnose the low urea pressure fault in both the urea pre-injection stage and the urea injection stage, and recover the fault by improving the urea flow after diagnosing the low urea pressure fault, thereby avoiding the fault of the urea injection system and improving the robustness of fault diagnosis.
Description
Technical Field
The application relates to the technical field of fault diagnosis of a vehicle urea injection system, in particular to a method for improving the diagnosis robustness of the urea injection system.
Background
In order to reduce the emission of NOx and particles in the tail gas of the engine, the national diesel engine is matched with a post-treatment system of a catalytic oxidizer (DOC) +a particle filter (DPF) +a selective oxidation-reduction device (SCR), urea is injected into an exhaust pipe through a urea injection system, and then the urea is decomposed into NH3 and reacts with the NOx to reduce the emission of the NOx.
The national sixth emission regulation requires that the urea injection system is monitored, if the urea injection system fails and urea cannot be injected normally, the fault is reported, and torsion and speed limitation are carried out on the vehicle.
If air exists in the urea, bubbles can be attached to the periphery of the pressure sensor in the running process of the urea pump, so that the measurement result of the pressure sensor in the urea pump is smaller, a fault that the urea pressure is low is reported, and if the urea pressure is low, the vehicle can cause vehicle torque limitation.
Disclosure of Invention
The embodiment of the application provides a method for improving the diagnosis robustness of a urea injection system, which aims to solve the problem that in the related art, air in urea can cause low-pressure failure of the reported urea and cause torsion and speed limitation of a vehicle.
The first aspect of the embodiment of the application provides a method for improving the diagnostic robustness of a urea injection system, the urea injection system comprises an air pipeline and a urea pipeline which are connected with a urea nozzle, an air electromagnetic valve and an air pressure sensor are sequentially connected in series on the air pipeline, and a urea pump and a urea pressure sensor are sequentially connected in series on the urea pipeline, and the method comprises the following steps:
s1, monitoring the urea pressure by a urea pressure sensor in a urea pre-injection stage, wherein the injection quantity of a urea pump is 500-20000g/h during pre-injection, the urea pre-injection duration is more than 60S, the urea pressure is less than 150kpa, the low urea pressure fault in the pre-injection stage is diagnosed, and if not, the next step is carried out;
s2, in the urea injection stage, the urea pressure sensor always monitors the injection pressure of urea, and when the injection quantity is 500-10000g/h, the urea injection duration is more than 60S and the urea pressure is less than 150kpa, the low urea pressure fault in the injection stage is diagnosed.
In some embodiments, the method further comprises:
s3, after the low urea pressure fault is diagnosed, controlling the urea injection quantity to be 1000-10000g/h by the urea pump, and continuing for 0.5-30min to remove bubbles in the urea solution, and then diagnosing the low urea pressure fault again, wherein if the low urea pressure fault is eliminated, the urea injection system works normally, and the low urea pressure fault is not reported any more;
if the low urea pressure faults are not eliminated, triggering the urea pump again to control the urea injection quantity to be 1000-10000g/h for 0.5-30min so as to remove bubbles in the urea solution, and if the low urea pressure faults are not eliminated after triggering for 3 times, reporting the low urea pressure faults, wherein the urea injection system does not work any more.
In some embodiments, the urea injection system further comprises a one-way valve connected between the air line and the urea line, and a cooling line connected to the urea nozzle, the cooling line having a cooling solenoid valve connected in series.
The second aspect of the embodiment of the application provides a method for improving the diagnostic robustness of a urea injection system, the urea injection system comprises an air pipeline and a urea pipeline which are connected with a urea nozzle, an air electromagnetic valve, a proportional valve and an air pressure sensor are sequentially connected in series on the air pipeline, and a urea pump and a urea pressure sensor are sequentially connected in series on the urea pipeline, and the method comprises the following steps:
s1, monitoring the urea pressure by a urea pressure sensor in a urea pre-injection stage, wherein the injection quantity of a urea pump is 500-20000g/h during pre-injection, the urea pre-injection duration is more than 60S, the urea pressure is less than 150kpa, the low urea pressure fault in the pre-injection stage is diagnosed, and if not, the next step is carried out;
s2, in the urea injection stage, the urea pressure sensor always monitors the injection pressure of urea, and when the injection quantity is 500-10000g/h, the urea injection duration is more than 60S and the urea pressure is less than 150kpa, the low urea pressure fault in the injection stage is diagnosed.
In some embodiments, the method further comprises:
s3, after the low urea pressure fault is diagnosed, controlling the urea injection quantity to be 1000-10000g/h by the urea pump, and continuing for 0.5-30min to remove bubbles in the urea solution, and then diagnosing the low urea pressure fault again, wherein if the low urea pressure fault is eliminated, the urea injection system works normally, and the low urea pressure fault is not reported any more;
if the low urea pressure faults are not eliminated, triggering the urea pump again to control the urea injection quantity to be 1000-10000g/h for 0.5-30min so as to remove bubbles in the urea solution, and if the low urea pressure faults are not eliminated after triggering for 3 times, reporting the low urea pressure faults, wherein the urea injection system does not work any more.
In some embodiments, the urea injection system further comprises a purge solenoid valve connected between the air line and the urea line, and a cooling line connected to the urea nozzle, the cooling line having a cooling solenoid valve connected in series.
The third aspect of the embodiment of the application provides a method for improving the diagnostic robustness of a urea injection system, the urea injection system comprises an air pipeline and a urea pipeline which are connected with a urea nozzle, the air pipeline is sequentially connected with an air electromagnetic valve and a proportional valve in series, the urea pipeline is sequentially connected with a urea pump and a urea pressure sensor in series, and the method comprises the following steps:
s1, monitoring the urea pressure by a urea pressure sensor in a urea pre-injection stage, wherein the injection quantity of a urea pump is 500-20000g/h during pre-injection, the urea pre-injection duration is more than 60S, the urea pressure is less than 150kpa, the low urea pressure fault in the pre-injection stage is diagnosed, and if not, the next step is carried out;
s2, in the urea injection stage, the urea pressure sensor always monitors the injection pressure of urea, and when the injection quantity is 500-10000g/h, the urea injection duration is more than 60S and the urea pressure is less than 150kpa, the low urea pressure fault in the injection stage is diagnosed.
In some embodiments, the method further comprises:
s3, after the low urea pressure fault is diagnosed, controlling the urea injection quantity to be 1000-10000g/h by the urea pump, and continuing for 0.5-30min to remove bubbles in the urea solution, and then diagnosing the low urea pressure fault again, wherein if the low urea pressure fault is eliminated, the urea injection system works normally, and the low urea pressure fault is not reported any more;
if the low urea pressure faults are not eliminated, triggering the urea pump again to control the urea injection quantity to be 1000-10000g/h for 0.5-30min so as to remove bubbles in the urea solution, and if the low urea pressure faults are not eliminated after triggering for 3 times, reporting the low urea pressure faults, wherein the urea injection system does not work any more.
In some embodiments, the urea injection system further comprises a purge solenoid valve connected between the air line and the urea line, and a cooling line connected to the urea nozzle, the cooling line having a cooling solenoid valve connected in series.
In some embodiments, an air filter is further connected in series on the air line, a urea filter is further connected in series on the urea line, and a cooling water filter is further connected in series on the cooling line.
The technical scheme provided by the application has the beneficial effects that:
the embodiment of the application provides a method for improving the diagnostic robustness of a urea injection system, which is characterized in that in the urea pre-injection stage, a urea pressure sensor monitors the urea pressure, the injection quantity of a urea pump is 500-20000g/h during pre-injection, the duration of urea pre-injection is more than 60s, the urea pressure is less than 150kpa, then the low urea pressure fault in the pre-injection stage is diagnosed, and if not, the next step is carried out; in the urea injection stage, the urea pressure sensor always monitors the injection pressure of urea, and when the injection quantity is 500-10000g/h, the urea injection duration is more than 60s and the urea pressure is less than 150kpa, the low urea pressure fault in the injection stage is diagnosed. Therefore, the method for improving the diagnosis robustness of the urea injection system can diagnose the low urea pressure fault in both the urea pre-injection stage and the urea injection stage, and recover the fault by improving the urea flow after diagnosing the low urea pressure fault, thereby avoiding the fault of the urea injection system and improving the robustness of fault diagnosis.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for the description of the embodiments will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present application, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a flow chart of a method according to an embodiment of the present application;
FIG. 2 is a schematic diagram of a first embodiment of the present application;
FIG. 3 is a schematic diagram of a second embodiment of the present application;
fig. 4 is a schematic structural view of a third embodiment of the present application.
Reference numerals:
1. an air line; 2. a urea line; 3. an air solenoid valve; 4. an air pressure sensor; 5. a urea pump; 6. a urea pressure sensor; 7. a urea nozzle; 8. a one-way valve; 9. a proportional valve; 10. purging the electromagnetic valve; 11. an air filter element; 12. urea filter element; 13. a cooling pipeline; 14. a cooling water cartridge; 15. and cooling the electromagnetic valve.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present application more apparent, the technical solutions of the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application, and it is apparent that the described embodiments are some embodiments of the present application, but not all embodiments of the present application. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.
The embodiment of the application provides a method for improving the diagnosis robustness of a urea injection system, which can solve the problem that in the related art, air in urea can cause low-pressure failure of the reported urea and cause torsion and speed limitation of a vehicle.
Referring to fig. 1 and 2, a first aspect of the present embodiment provides a method for improving the diagnostic robustness of a urea injection system, wherein the urea injection system comprises an air line 1 and a urea line 2, both connected to a urea nozzle 7. An air solenoid valve 3 and an air pressure sensor 4 are sequentially connected in series with the air pipeline 1, and compressed air sequentially enters a urea nozzle 7 through the air solenoid valve 3 and the air pressure sensor 4 to atomize urea solution. The urea pipeline 2 is sequentially connected with a urea pump 5 and a urea pressure sensor 6 in series, and urea sequentially enters a urea nozzle 7 through the urea pump 5 and the urea pressure sensor 6 to spray urea solution to SCR. The method comprises the following steps:
s1, monitoring the urea pressure by a urea pressure sensor 6 in a urea pre-injection stage, wherein the injection quantity of a urea pump 5 is 500-20000g/h, such as 6000g/h, when the urea pre-injection duration is longer than 60S, and when the urea pressure is less than 150kpa, such as 10kpa, the low urea pressure fault in the pre-injection stage is diagnosed, and if not, the next step is carried out.
S2, in the urea injection stage, the urea pressure sensor 6 always monitors the injection pressure of urea, the injection quantity of the urea pump 5 is 500-10000g/h, such as 6000g/h, the urea injection duration is more than 60S, and when the urea pressure is less than 150kpa, such as 10kpa, the low urea pressure fault in the injection stage is diagnosed.
In some alternative embodiments, referring to fig. 1 and 2, embodiments of the present application provide a method for improving diagnostic robustness of a urea injection system, the method further comprising the steps of:
and S3, after the low urea pressure fault is diagnosed, the urea pump 5 controls the urea injection quantity to be 1000-10000g/h, for example 7000g/h, and the urea injection quantity lasts for 0.5-30min, for example 10min, so as to remove bubbles in the urea solution, then the low urea pressure fault diagnosis is performed again, and if the low urea pressure fault is eliminated, the urea injection system works normally and no low urea pressure fault is reported.
If the low urea pressure faults are not eliminated, triggering the urea pump again to control the urea injection quantity to 1000-10000g/h, such as 7000g/h, for 0.5-30min, such as 10min, so as to remove bubbles in the urea solution, and if the low urea pressure faults are not eliminated after triggering for 3 times, reporting the low urea pressure faults, and the urea injection system does not work any more.
In some alternative embodiments, referring to fig. 1 and 2, an embodiment of the present application provides a method for improving the diagnostic robustness of a urea injection system, the urea injection system of the method further comprising a check valve 8 connected between the air line 1 and the urea line 2, and a cooling line 13 connected to the urea nozzle 7, a cooling solenoid valve 15 being connected in series to the cooling line 13. The air pipeline 1 is also connected with an air filter element 11 in series, the urea pipeline 2 is also connected with a urea filter element 12 in series, and the cooling pipeline 13 is also connected with a cooling water filter element 14 in series. A one-way valve 8 is connected between the air pipeline 1 and the urea pipeline 2, and after the one-way valve 8 is opened, the urea solution in the urea pipeline 2 is purged by compressed air, so that the urea nozzle 7 is prevented from crystallizing. The cooling pipeline 13 and the cooling electromagnetic valve 15 are used for injecting cooling liquid into the urea nozzle 7 so as to reduce the working temperature of the urea nozzle 7 and prevent the urea nozzle 7 from being blocked after the urea nozzle 7 has crystallization faults.
Referring to fig. 1 and 3, a second aspect of the embodiment of the present application provides a method for improving the diagnostic robustness of a urea injection system comprising an air line 1 and a urea line 2, both connected to a urea nozzle 7. An air solenoid valve 3, a proportional valve 9 and an air pressure sensor 4 are sequentially connected in series on the air pipeline 1, and compressed air sequentially enters a urea nozzle 7 through the air solenoid valve 3, the proportional valve 9 and the air pressure sensor 4 to atomize urea solution. The urea pipeline 2 is sequentially connected with a urea pump 5 and a urea pressure sensor 6 in series, and urea sequentially enters a urea nozzle 7 through the urea pump 5 and the urea pressure sensor 6 to spray urea solution to SCR. The method comprises the following steps:
s1, monitoring the urea pressure by a urea pressure sensor 6 in a urea pre-injection stage, wherein the injection quantity of a urea pump 5 is 500-20000g/h, such as 6000g/h, when the urea pre-injection duration is longer than 60S, and when the urea pressure is less than 150kpa, such as 10kpa, diagnosing that the urea pressure in the pre-injection stage is low, and if not, entering the next step.
S2, in the urea injection stage, the urea pressure sensor 6 always monitors the injection pressure of urea, the injection quantity of the urea pump 5 is 500-10000g/h, such as 6000g/h, the urea injection duration is more than 60S, and when the urea pressure is less than 150kpa, such as 10kpa, the low urea pressure fault in the injection stage is diagnosed.
In some alternative embodiments, referring to fig. 1 and 3, embodiments of the present application provide a method for improving diagnostic robustness of a urea injection system, the method further comprising the steps of:
and S3, after the low urea pressure fault is diagnosed, the urea pump 5 controls the urea injection quantity to be 1000-10000g/h, for example 7000g/h, and the urea injection quantity lasts for 0.5-30min, for example 10min, so as to remove bubbles in the urea solution, then the low urea pressure fault diagnosis is performed again, and if the low urea pressure fault is eliminated, the urea injection system works normally and no low urea pressure fault is reported.
If the low urea pressure faults are not eliminated, triggering the urea pump again to control the urea injection quantity to 1000-10000g/h, such as 7000g/h, for 0.5-30min, such as 10min, so as to remove bubbles in the urea solution, and if the low urea pressure faults are not eliminated after triggering for 3 times, reporting the low urea pressure faults, and the urea injection system does not work any more.
In some alternative embodiments, referring to fig. 1 and 3, an embodiment of the present application provides a method for improving the diagnostic robustness of a urea injection system, the urea injection system of the method further comprising a purge solenoid valve 10 connected between the air line 1 and the urea line 2, and a cooling line 13 connected to the urea nozzle 7, the cooling line 13 being connected in series with a cooling solenoid valve 15. The air pipeline 1 is also connected with an air filter element 11 in series, the urea pipeline 2 is also connected with a urea filter element 12 in series, and the cooling pipeline 13 is also connected with a cooling water filter element 14 in series. After the purge solenoid valve 10 is opened, the urea solution in the urea pipeline 2 is purged by compressed air, and crystallization of the urea nozzle 7 is prevented. The cooling pipeline 13 and the cooling electromagnetic valve 15 are used for injecting cooling liquid into the urea nozzle 7 so as to reduce the working temperature of the urea nozzle 7 and prevent the urea nozzle 7 from being blocked after the urea nozzle 7 has crystallization faults.
Referring to fig. 1 and 4, a third aspect of the embodiment of the present application provides a method for improving the diagnostic robustness of a urea injection system comprising an air line 1 and a urea line 2, both connected to a urea nozzle 7. An air solenoid valve 3 and a proportional valve 9 are sequentially connected in series on the air pipeline 1, and compressed air sequentially enters a urea nozzle 7 through the air solenoid valve 3 and the proportional valve 9 to atomize urea solution. The urea pipeline 2 is sequentially connected with a urea pump 5 and a urea pressure sensor 6 in series, and urea sequentially enters a urea nozzle 7 through the urea pump 5 and the urea pressure sensor 6 to spray urea solution to SCR. The method comprises the following steps:
s1, monitoring the urea pressure by a urea pressure sensor 6 in a urea pre-injection stage, wherein the injection quantity of a urea pump 5 is 500-20000g/h, such as 6000g/h, when the urea pre-injection duration is longer than 60S, and when the urea pressure is less than 150kpa, such as 10kpa, diagnosing that the urea pressure in the pre-injection stage is low, and if not, entering the next step.
S2, in the urea injection stage, the urea pressure sensor 6 always monitors the injection pressure of urea, the injection quantity of the urea pump 5 is 500-10000g/h, such as 6000g/h, the urea injection duration is more than 60S, and when the urea pressure is less than 150kpa, such as 10kpa, the low urea pressure fault in the injection stage is diagnosed.
In some alternative embodiments, referring to fig. 1 and 4, embodiments of the present application provide a method for improving diagnostic robustness of a urea injection system, the method further comprising the steps of:
and S3, after the low urea pressure fault is diagnosed, the urea pump 5 controls the urea injection quantity to be 1000-10000g/h, for example 7000g/h, and the urea injection quantity lasts for 0.5-30min, for example 10min, so as to remove bubbles in the urea solution, then the low urea pressure fault diagnosis is performed again, and if the low urea pressure fault is eliminated, the urea injection system works normally and no low urea pressure fault is reported.
If the low urea pressure faults are not eliminated, triggering the urea pump again to control the urea injection quantity to 1000-10000g/h, such as 7000g/h, for 0.5-30min, such as 10min, so as to remove bubbles in the urea solution, and if the low urea pressure faults are not eliminated after triggering for 3 times, reporting the low urea pressure faults, and the urea injection system does not work any more.
In some alternative embodiments, see fig. 4, the urea injection system further comprises a purge solenoid valve 10 connected between the air line 1 and the urea line 2, and a cooling line 13 connected to the urea nozzle 7, a cooling solenoid valve 15 being connected in series to the cooling line 13. The air pipeline 1 is also connected with an air filter element 11 in series, the urea pipeline 2 is also connected with a urea filter element 12 in series, and the cooling pipeline 13 is also connected with a cooling water filter element 14 in series. After the purge solenoid valve 10 is opened, the urea solution in the urea pipeline 2 is purged by compressed air, and crystallization of the urea nozzle 7 is prevented. The cooling pipeline 13 and the cooling electromagnetic valve 15 are used for injecting cooling liquid into the urea nozzle 7 so as to reduce the working temperature of the urea nozzle 7 and prevent the urea nozzle 7 from being blocked after the urea nozzle 7 has crystallization faults.
Principle of operation
The embodiment of the application provides a method for improving the diagnosis robustness of a urea injection system, which is characterized in that in the urea pre-injection stage, a urea pressure sensor 6 monitors the pressure of urea, the injection quantity of a urea pump 5 is 500-20000g/h during pre-injection, the duration of urea pre-injection is more than 60s, the urea pressure is less than 150kpa, then the low urea pressure fault in the pre-injection stage is diagnosed, and if not, the next step is carried out; in the urea injection stage, the urea pressure sensor 6 always monitors the injection pressure of urea, the injection quantity of the urea pump 5 is 500-10000g/h during injection, the urea injection duration is more than 60s, and when the urea pressure is less than 150kpa, the low urea pressure fault in the injection stage is diagnosed. Therefore, the method for improving the diagnosis robustness of the urea injection system can diagnose the low urea pressure fault in both the urea pre-injection stage and the urea injection stage, and recover the fault by improving the urea flow after diagnosing the low urea pressure fault, thereby avoiding the fault of the urea injection system and improving the robustness of fault diagnosis.
In the description of the present application, it should be noted that the azimuth or positional relationship indicated by the terms "upper", "lower", etc. are based on the azimuth or positional relationship shown in the drawings, and are merely for convenience of describing the present application and simplifying the description, and are not indicative or implying that the apparatus or element in question must have a specific azimuth, be constructed and operated in a specific azimuth, and thus should not be construed as limiting the present application. Unless specifically stated or limited otherwise, the terms "mounted," "connected," and "coupled" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art according to the specific circumstances.
It should be noted that in the present application, relational terms such as "first" and "second" and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.
The foregoing is only a specific embodiment of the application to enable those skilled in the art to understand or practice the application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (7)
1. A method for improving diagnostic robustness of a urea injection system, characterized by: the urea injection system comprises an air pipeline (1) and a urea pipeline (2) which are connected with a urea nozzle (7), wherein an air solenoid valve (3) and an air pressure sensor (4) are sequentially connected in series on the air pipeline (1), and a urea pump (5) and a urea pressure sensor (6) are sequentially connected in series on the urea pipeline (2), and the method comprises the following steps:
s1, monitoring the urea pressure by a urea pressure sensor (6) in a urea pre-injection stage, wherein the injection quantity of a urea pump (5) is 500-20000g/h during pre-injection, the duration of urea pre-injection is more than 60S, the urea pressure is less than 150kpa, and if the urea pressure is less than 150kpa, diagnosing that the urea pressure in the pre-injection stage is low, otherwise, entering the next step;
s2, in a urea injection stage, a urea pressure sensor (6) always monitors the injection pressure of urea, the injection quantity of a urea pump (5) is 500-10000g/h during injection, the urea injection duration is more than 60S, and when the urea pressure is less than 150kpa, the low urea pressure fault in the injection stage is diagnosed;
s3, after the low urea pressure fault is diagnosed, controlling the urea injection quantity to be 1000-10000g/h by a urea pump (5) and lasting for 0.5-30min to remove bubbles in the urea solution, and then performing low urea pressure fault diagnosis again, wherein if the low urea pressure fault is eliminated, the urea injection system works normally and no low urea pressure fault is reported;
if the urea pressure low fault is not eliminated, triggering the urea pump (5) again to control the urea injection quantity to be 1000-10000g/h for 0.5-30min so as to remove bubbles in the urea solution, and if the urea pressure low fault is not eliminated after triggering for 3 times, reporting the urea pressure low fault, and the urea injection system does not work any more.
2. A method of improving diagnostic robustness of a urea injection system as set forth in claim 1, wherein:
the urea injection system further comprises a one-way valve (8) connected between the air pipeline (1) and the urea pipeline (2), and a cooling pipeline (13) connected with the urea nozzle (7), wherein the cooling pipeline (13) is connected with a cooling electromagnetic valve (15) in series.
3. A method for improving diagnostic robustness of a urea injection system, characterized by: the urea injection system comprises an air pipeline (1) and a urea pipeline (2) which are connected with a urea nozzle (7), wherein an air electromagnetic valve (3), a proportional valve (9) and an air pressure sensor (4) are sequentially connected in series on the air pipeline (1), a urea pump (5) and a urea pressure sensor (6) are sequentially connected in series on the urea pipeline (2), and the method comprises the following steps:
s1, monitoring the urea pressure by a urea pressure sensor (6) in a urea pre-injection stage, wherein the injection quantity of a urea pump (5) is 500-20000g/h during pre-injection, the duration of urea pre-injection is more than 60S, the urea pressure is less than 150kpa, and if the urea pressure is less than 150kpa, diagnosing that the urea pressure in the pre-injection stage is low, otherwise, entering the next step;
s2, in a urea injection stage, a urea pressure sensor (6) always monitors the injection pressure of urea, the injection quantity of a urea pump (5) is 500-10000g/h during injection, the urea injection duration is more than 60S, and when the urea pressure is less than 150kpa, the low urea pressure fault in the injection stage is diagnosed;
s3, after the low urea pressure fault is diagnosed, controlling the urea injection quantity to be 1000-10000g/h by a urea pump (5) and lasting for 0.5-30min to remove bubbles in the urea solution, and then performing low urea pressure fault diagnosis again, wherein if the low urea pressure fault is eliminated, the urea injection system works normally and no low urea pressure fault is reported;
if the urea pressure low fault is not eliminated, triggering the urea pump (5) again to control the urea injection quantity to be 1000-10000g/h for 0.5-30min so as to remove bubbles in the urea solution, and if the urea pressure low fault is not eliminated after triggering for 3 times, reporting the urea pressure low fault, and the urea injection system does not work any more.
4. A method of improving diagnostic robustness of a urea injection system as claimed in claim 3, characterized by:
the urea injection system further comprises a purging electromagnetic valve (10) connected between the air pipeline (1) and the urea pipeline (2), and a cooling pipeline (13) connected with the urea nozzle (7), wherein the cooling pipeline (13) is connected with a cooling electromagnetic valve (15) in series.
5. A method for improving diagnostic robustness of a urea injection system, characterized by: the urea injection system comprises an air pipeline (1) and a urea pipeline (2), wherein the air pipeline (1) and the urea pipeline (2) are connected with a urea nozzle (7) in series, an air electromagnetic valve (3) and a proportional valve (9) are sequentially connected with the air pipeline (1), and a urea pump (5) and a urea pressure sensor (6) are sequentially connected with the urea pipeline (2) in series, and the method comprises the following steps:
s1, monitoring the urea pressure by a urea pressure sensor (6) in a urea pre-injection stage, wherein the injection quantity of a urea pump (5) is 500-20000g/h during pre-injection, the duration of urea pre-injection is more than 60S, the urea pressure is less than 150kpa, and if the urea pressure is less than 150kpa, diagnosing that the urea pressure in the pre-injection stage is low, otherwise, entering the next step;
s2, in a urea injection stage, a urea pressure sensor (6) always monitors the injection pressure of urea, the injection quantity of a urea pump (5) is 500-10000g/h during injection, the urea injection duration is more than 60S, and when the urea pressure is less than 150kpa, the low urea pressure fault in the injection stage is diagnosed;
s3, after the low urea pressure fault is diagnosed, controlling the urea injection quantity to be 1000-10000g/h by a urea pump (5) and lasting for 0.5-30min to remove bubbles in the urea solution, and then performing low urea pressure fault diagnosis again, wherein if the low urea pressure fault is eliminated, the urea injection system works normally and no low urea pressure fault is reported;
if the urea pressure low fault is not eliminated, triggering the urea pump (5) again to control the urea injection quantity to be 1000-10000g/h for 0.5-30min so as to remove bubbles in the urea solution, and if the urea pressure low fault is not eliminated after triggering for 3 times, reporting the urea pressure low fault, and the urea injection system does not work any more.
6. A method of improving diagnostic robustness of a urea injection system as set forth in claim 5, wherein:
the urea injection system further comprises a purging electromagnetic valve (10) connected between the air pipeline (1) and the urea pipeline (2), and a cooling pipeline (13) connected with the urea nozzle (7), wherein the cooling pipeline (13) is connected with a cooling electromagnetic valve (15) in series.
7. A method of improving diagnostic robustness of a urea injection system as set forth in claim 6, wherein:
an air filter element (11) is further connected in series on the air pipeline (1), a urea filter element (12) is further connected in series on the urea pipeline (2), and a cooling water filter element (14) is further connected in series on the cooling pipeline (13).
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