CN110131024A - A kind of leakage detection method and device of urea - Google Patents
A kind of leakage detection method and device of urea Download PDFInfo
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- CN110131024A CN110131024A CN201910630806.1A CN201910630806A CN110131024A CN 110131024 A CN110131024 A CN 110131024A CN 201910630806 A CN201910630806 A CN 201910630806A CN 110131024 A CN110131024 A CN 110131024A
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- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 title claims abstract description 129
- 239000004202 carbamide Substances 0.000 title claims abstract description 129
- 238000001514 detection method Methods 0.000 title claims abstract description 35
- 238000005070 sampling Methods 0.000 claims description 70
- 230000008859 change Effects 0.000 claims description 63
- 238000000034 method Methods 0.000 claims description 41
- 238000004364 calculation method Methods 0.000 claims description 7
- 239000002699 waste material Substances 0.000 abstract description 7
- MWUXSHHQAYIFBG-UHFFFAOYSA-N Nitric oxide Chemical compound O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 18
- 230000008569 process Effects 0.000 description 10
- 238000010586 diagram Methods 0.000 description 8
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 6
- 230000009471 action Effects 0.000 description 6
- 239000007789 gas Substances 0.000 description 6
- 239000003054 catalyst Substances 0.000 description 3
- 230000003647 oxidation Effects 0.000 description 3
- 238000007254 oxidation reaction Methods 0.000 description 3
- 230000009467 reduction Effects 0.000 description 3
- 238000006722 reduction reaction Methods 0.000 description 3
- 239000000243 solution Substances 0.000 description 3
- 230000003197 catalytic effect Effects 0.000 description 2
- 238000010531 catalytic reduction reaction Methods 0.000 description 2
- 229910000069 nitrogen hydride Inorganic materials 0.000 description 2
- 229910021529 ammonia Inorganic materials 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 230000000750 progressive effect Effects 0.000 description 1
Classifications
-
- 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
-
- 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
- F01N13/00—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00
-
- 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]
-
- 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
Landscapes
- Engineering & Computer Science (AREA)
- 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)
- Examining Or Testing Airtightness (AREA)
Abstract
The invention discloses a kind of leakage detection methods of urea, it include: when the urea pump for detecting goal systems is in stable state under normal pressure setting value, the pressure value of the urea pump is increased to first pressure setting value, wherein, the first pressure setting value is greater than the normal pressure setting value；When the urea pump is in stable state under the first pressure setting value, the pressure value of the urea pump is reduced to second pressure setting value, wherein the second pressure setting value is less than the normal pressure setting value；After the completion of adjustment, the current pressure values and the sampled pressure value at corresponding time point for obtaining the goal systems determine whether the goal systems leaks according to the current pressure values and the sampled pressure value difference value.Above-mentioned detection method does not need to increase additional detection device in system operation, so that it may which whether urea is revealed in detection system, waste caused by avoiding because of urea leakage.
Description
Technical Field
The invention relates to the technical field of detection, in particular to a urea leakage detection method and device.
Background
Urea stored in the pipeline is easy to cause leakage due to the existence of the connecting part of the pipeline, such as a Selective Catalytic Reduction (SCR) which is a treatment process for NOx in tail gas emission of diesel vehicles, namely, urea is injected to reduce NOx in the tail gas into N2 and H2O under the action of a catalyst. The technology is also widely applied to the post-treatment of the tail gas of the diesel engine, the generation of particle PM is controlled as much as possible in the machine by optimizing the oil injection and combustion processes, then the nitrogen oxide formed under the oxygen-rich condition is treated outside the machine, and the selective catalytic reduction is carried out on the nitrogen oxide (NOx) by using the vehicle urea (the vehicle urea is decomposed at a certain temperature to generate ammonia), so that the aims of saving energy and reducing emission are fulfilled.
However, SCR is complex, leakage points are many, discovery is difficult, urea waste is easy to cause especially under the condition that slight leakage does not affect urea pressure build-up, and a urea leakage detection method is lacked to avoid urea leakage waste.
Disclosure of Invention
In view of this, the present invention provides a method and an apparatus for detecting urea leakage, so as to solve the problem of waste caused by urea leakage, and the specific scheme is as follows:
a method of leak detection of urea, comprising:
when detecting that a urea pump of a target system is in a stable state under a normal pressure set value, increasing the pressure value of the urea pump to a first pressure set value, wherein the first pressure set value is larger than the normal pressure set value;
when the urea pump is in a steady state at the first pressure set point, reducing the pressure value of the urea pump to a second pressure set point, wherein the second pressure set point is less than the normal pressure set point;
and after the adjustment is finished, acquiring a current pressure value of the target system and a sampling pressure value of a corresponding time point, and determining whether the target system leaks or not according to a difference value between the current pressure value and the sampling pressure value.
The above method, optionally, further includes:
detecting whether the urea pump has a fault;
and if so, sending a fault instruction to prompt the fault of the urea pump.
The above method, optionally, further includes:
and storing the current pressure value and the sampling pressure value.
Optionally, in the method, after the adjustment is completed, obtaining a current pressure value of the target system and a sampling pressure value at a corresponding time point, and determining whether the target system leaks according to a difference between the current pressure value and the sampling pressure value, where the method includes:
acquiring a sampling pressure value of the urea pump at the time point at a preset first time interval after acquiring the current pressure value;
calculating a pressure difference value between the current pressure value and the sampling pressure value;
comparing the pressure difference value with a preset pressure difference threshold value, and judging whether the pressure difference value is greater than the preset pressure difference threshold value;
if yes, judging that the target system has leakage, or if not, judging that the target system does not have leakage.
Optionally, in the method, after the adjustment is completed, obtaining a current pressure value of the target system and a sampling pressure value at a corresponding time point, and determining whether the target system leaks according to a difference between the current pressure value and the sampling pressure value, where the method includes:
acquiring the sampling pressure value at a preset second time interval after acquiring the current pressure value;
when the number of the sampling pressure values or the total time of the intervals meets the corresponding threshold value requirement, calculating the pressure change rate between the adjacent pressure values and the average pressure change rate of each pressure change rate;
comparing the average pressure change rate with a preset pressure change rate threshold value, and judging whether the average pressure change rate is greater than the preset pressure change rate threshold value;
if yes, judging that the target system has leakage, or if not, judging that the target system does not have leakage.
A urea leak detection device comprising:
the system comprises an increasing module, a judging module and a control module, wherein the increasing module is used for increasing the pressure value of a urea pump of a target system to a first pressure set value when the urea pump is detected to be in a stable state under a normal pressure set value, and the first pressure set value is larger than the normal pressure set value;
the reducing module is used for reducing the pressure value of the urea pump to a second pressure set value when the urea pump is in a stable state under the first pressure set value, wherein the second pressure set value is smaller than the normal pressure set value;
and the acquisition determining module is used for acquiring the current pressure value of the target system and the sampling pressure value of the corresponding time point after the adjustment is finished, and determining whether the target system leaks or not according to the difference value between the current pressure value and the sampling pressure value.
The above apparatus, optionally, further comprises:
the detection module is used for detecting whether the urea pump has a fault;
and the prompting module is used for sending a fault instruction to prompt the fault of the urea pump if the fault instruction is positive.
The above apparatus, optionally, further comprises:
and the storage module is used for storing the current pressure value and the sampling pressure value.
The above apparatus, optionally, the obtaining determining module includes:
the first obtaining unit is used for obtaining the sampling pressure value of the urea pump at the time point at a first time interval preset after the current pressure value is obtained;
the first calculation unit is used for calculating a pressure difference value between the current pressure value and the sampling pressure value;
the first comparison and judgment unit is used for comparing the pressure difference value with a preset pressure difference threshold value and judging whether the pressure difference value is larger than the preset pressure difference threshold value or not;
the first judging unit is used for judging that the target system has leakage if the target system has leakage, or judging that the target system does not have leakage if the target system does not have leakage.
The above apparatus, optionally, the obtaining determining module includes:
the second obtaining unit is used for obtaining the sampling pressure value at a preset second time interval after the current pressure value is obtained;
the second calculation unit is used for calculating the pressure change rate between the adjacent pressure values and the average pressure change rate of each pressure change rate when the number of the sampling pressure values or the total duration of the intervals meets the corresponding threshold requirement;
the second comparison and judgment unit is used for comparing the average pressure change rate with a preset pressure change rate threshold value and judging whether the average pressure change rate is larger than the preset pressure change rate threshold value or not;
and the second judging unit is used for judging that the target system has leakage if the target system has leakage, or judging that the target system does not have leakage if the target system has no leakage.
Compared with the prior art, the invention has the following advantages:
the invention discloses a urea leakage detection method, which comprises the following steps: when detecting that a urea pump of a target system is in a stable state under a normal pressure set value, increasing the pressure value of the urea pump to a first pressure set value, wherein the first pressure set value is larger than the normal pressure set value; when the urea pump is in a steady state at the first pressure set point, reducing the pressure value of the urea pump to a second pressure set point, wherein the second pressure set point is less than the normal pressure set point; and after the adjustment is finished, acquiring a current pressure value of the target system and a sampling pressure value of a corresponding time point, and determining whether the target system leaks or not according to a difference value between the current pressure value and the sampling pressure value. According to the detection method, whether the urea in the system leaks can be detected without adding extra detection equipment in the running process of the system, so that waste caused by urea leakage is avoided.
Of course, it is not necessary for any product in which the invention is practiced to achieve all of the above-described advantages at the same time.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a block diagram of a selective catalytic oxidation system disclosed in an embodiment of the present application;
FIG. 2 is a flow chart of a method for leak testing urea according to an embodiment of the present disclosure;
FIG. 3 is a flow chart illustrating a method for detecting urea leakage based on pressure differential according to an embodiment of the present disclosure;
FIG. 4 is a schematic diagram illustrating a pump pressure change according to an embodiment of the present disclosure;
FIG. 5 is a flow chart illustrating a method for detecting urea slip based on a rate of change of pressure as disclosed in an embodiment of the present application;
fig. 6 is a block diagram of a urea leakage detection device according to an embodiment of the present application.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. 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 invention. Thus, the present invention 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.
The invention discloses a urea leakage detection method and a device, which are applied to a urea leakage detection process, and the urea leakage detection process in SCR is taken as an example in the embodiment of the invention for explanation, wherein the whole working block diagram of SCR is shown in figure 1, the flow of exhaust gas enters an oxidation catalyst through an exhaust pipe for pretreatment, emission reduction and filtration through a diesel particulate filter, when the exhaust gas enters a selective catalytic oxidation device, a urea pump sucks urea from a urea tank and pressurizes the urea, the urea is fed to a urea nozzle through a pipeline, and the urea in the pipe is hydrolyzed into NH3, NH3 and NOx in the flow of the exhaust gas react under the action of a catalyst to generate N2 and H2O. Because there are many pipeline connecting parts, which are likely to cause urea leakage, an embodiment of the present invention provides a method for detecting urea leakage, where the execution flow of the method is shown in fig. 2, and the method includes the following steps:
s101, when a urea pump of a target system is detected to be in a stable state under a normal pressure set value, increasing the pressure value of the urea pump to a first pressure set value, wherein the first pressure set value is larger than the normal pressure set value;
in the embodiment of the invention, a urea pump adopts a feedforward plus closed-loop control mode, wherein a normal pressure set value of the urea pump is preset, the normal pressure set value is a working pressure value of the urea pump under a normal condition, the normal pressure set value can be modified through software, when an actual pressure value of the urea pump fluctuates in a fluctuation range allowed by the normal pressure setting and a duration of the actual pressure value of the urea pump meets a certain duration, the urea pump of the target system is judged to be in a stable state under the normal pressure set value, the pressure value of the urea pump is increased to a first pressure set value, the first pressure set value is larger than the normal pressure set value, the allowable fluctuation range, the certain duration and the first pressure set value can be set according to experience or specific conditions, the allowable fluctuation range, the certain time length and the specific value of the first pressure set value are not limited in the invention.
S102, when the urea pump is in a stable state under the first pressure set value, reducing the pressure value of the urea pump to a second pressure set value, wherein the second pressure set value is smaller than the normal pressure set value;
in the embodiment of the present invention, a process of detecting whether the urea pump is in a stable state under the first pressure setting value is the same as a method of detecting the stable state under a standard pressure setting value, and details are not repeated herein, and if the urea pump is in the stable state, the pressure value of the urea pump is reduced to a second pressure setting value, where the second pressure setting value is smaller than the normal pressure setting value, and the second pressure setting value may be set according to experience or specific conditions.
S103, after the adjustment is completed, acquiring a current pressure value of the target system and a sampling pressure value of a corresponding time point, and determining whether the target system leaks or not according to a difference value between the current pressure value and the sampling pressure value.
In the embodiment of the invention, when the pressure value of the urea pump is reduced to the second pressure set value, the current pressure value of the target system and the sampling pressure value of the corresponding time point are obtained, wherein the selection of the current time point is related to the adopted method for determining whether the target system leaks, and whether the target system leaks is determined according to the difference value between the current pressure value and the sampling pressure value.
The invention discloses a urea leakage detection method, which comprises the following steps: when detecting that a urea pump of a target system is in a stable state under a normal pressure set value, increasing the pressure value of the urea pump to a first pressure set value, wherein the first pressure set value is larger than the normal pressure set value; when the urea pump is in a steady state at the first pressure set point, reducing the pressure value of the urea pump to a second pressure set point, wherein the second pressure set point is less than the normal pressure set point; and after the adjustment is finished, acquiring a current pressure value of the target system and a sampling pressure value of a corresponding time point, and determining whether the target system leaks or not according to a difference value between the current pressure value and the sampling pressure value. According to the detection method, whether the urea in the system leaks can be detected without adding extra detection equipment in the running process of the system, so that waste caused by urea leakage is avoided.
In the embodiment of the invention, the pressure change of the urea pump is detected by judging, and the basic idea is that after the pump pressure is stabilized to a normal pressure set value (9 Bar), the pressure is firstly increased to a larger value (such as 10 Bar), and after the pump pressure is stabilized near the set value, the pump pressure is adjusted to a smaller value (such as 7 Bar), so that the pressure change is more obvious after the pressure is switched from the larger value to the smaller value, and the higher the initial pressure is, the more obvious the pressure is, the pressure of the pump can be gradually reduced due to the closed-loop control action of the pressure of the pump, and the change trends of the pump pressure are different when urea leakage and urea leakage do not exist.
In the embodiment of the invention, when the urea pump is detected to be in a stable state under a normal pressure set value, whether the urea pump has a fault can be detected, if so, a fault instruction is sent to prompt the fault of the urea pump, and a maintenance worker maintains the urea pump according to the fault prompt, so that the fault caused by the fault of the urea pump can be eliminated when the target system has a fault.
In the embodiment of the present invention, after the adjustment is completed, a current pressure value of the target system and a sampling pressure value at a corresponding time point are obtained, and a flow of a method for determining whether the target system leaks according to a difference between the current pressure value and the sampling pressure value is shown in fig. 3, including the steps of:
s201, obtaining a sampling pressure value of the urea pump at the time point at a first time interval preset after obtaining the current pressure value;
in the embodiment of the invention, after the current pressure value is obtained, a timer is used for counting, and when a preset first time length is reached, the sampling pressure value of the urea pump is obtained at a corresponding time point, wherein the preset first time length can be set according to experience or specific conditions.
S202, calculating a pressure difference value between the current pressure value and the sampling pressure value;
in the embodiment of the invention, the difference between the current pressure value and the sampling pressure value is calculated to obtain the pressure difference value.
S203, comparing the pressure difference value with a preset pressure difference threshold value, and judging whether the pressure difference value is larger than the preset pressure difference threshold value;
in the embodiment of the present invention, the pressure difference value is compared with a preset pressure difference threshold value, and whether the pressure difference value is greater than the preset pressure difference threshold value is determined, where the preset pressure difference threshold value may be set according to experience or specific conditions.
S204, judging that the target system has leakage;
in the embodiment of the invention, because the pressure closed loop of the urea pump acts, the set pressure is lower than the actual pressure, the PI closed loop basically does not act (the output of the PI closed loop is the driving duty ratio, and the duty ratio has no negative value), the pressure can be rapidly reduced, and the pressure reduction speed is higher when urea leaks than when urea does not leak. The schematic diagram of the pump pressure change when there is a leak and no leak in the system is shown in fig. 4, and when the pressure difference value is greater than the preset pressure difference threshold value, it is determined that there is a leak in the target system.
S205, judging that the target system has no leakage.
In the embodiment of the invention, when the pressure difference value is smaller than the preset pressure difference threshold value, it is determined that no leakage exists in the target system.
In the embodiment of the present invention, after the adjustment is completed, a current pressure value of the target system and a sampling pressure value at a corresponding time point are obtained, and a flow of a method for determining whether the target system leaks according to a difference between the current pressure value and the sampling pressure value is shown in fig. 5, including the steps of:
s301, obtaining the sampling pressure value at a preset second time interval after obtaining the current pressure value;
in the embodiment of the present invention, the sampling pressure value is obtained at a preset second time interval after the current pressure value is obtained, where the preset second time interval may be set according to experience or specific conditions.
S302, when the number of the sampling pressure values or the total duration of the intervals meets the corresponding threshold requirement, calculating pressure change rates between adjacent pressure values and average pressure change rates of all the pressure change rates;
in the embodiment of the present invention, a sampling pressure value is acquired every preset second time interval, and when the number of the sampling pressure values or the total time interval reaches a corresponding threshold, a pressure change rate between adjacent pressure values is calculated, where the calculation method is as shown in formula (1):
（1）
wherein,-sampling pressure values at time t;
-sampling pressure values at time t-1;
-a preset second duration;
-rate of pressure change.
An average pressure change rate corresponding to each pressure change rate is calculated.
S303, comparing the average pressure change rate with a preset pressure change rate threshold value, and judging whether the average pressure change rate is greater than the preset pressure change rate threshold value or not;
in the embodiment of the present invention, the average pressure change rate is compared with a preset pressure change rate threshold, and whether the average pressure change rate is greater than the preset pressure change rate threshold is determined, where the preset pressure change rate threshold may be set according to experience or specific conditions.
S304, judging that the target system has leakage;
in an embodiment of the present invention, in the two implementation manners of determining whether the target system leaks according to the difference between the current pressure value and the sampling pressure value, for convenience of calling, the current pressure value and the sampling pressure value may be stored, for example: the current pressure value and the sampled pressure value may be stored in a designated database.
In the embodiment of the invention, because the pressure closed loop of the urea pump acts, the set pressure is lower than the actual pressure, the PI closed loop basically does not act (the output of the PI closed loop is the driving duty ratio, and the duty ratio has no negative value), the pressure can be rapidly reduced, and the pressure reduction speed is higher when urea leaks than when no urea leaks. The schematic diagram of the pump pressure change in the presence and absence of a leak in the system is shown in fig. 4, and when the average pressure change rate is greater than the preset pressure change rate threshold, it is determined that a leak exists in the target system.
S305, judging that the target system has no leakage.
In the embodiment of the present invention, when the average pressure change rate is smaller than the preset pressure change rate threshold, it is determined that there is no leakage in the target system.
Based on the urea leakage detection method, in an embodiment of the present invention, a pressure change detection device is further provided, and a structural block diagram of the detection device is shown in fig. 6, where the structural block diagram includes:
an increase module 401, a decrease module 402 and an acquisition determination module 403.
Wherein:
the increasing module 401 is configured to increase a pressure value of a urea pump of a target system to a first pressure set value when it is detected that the urea pump is in a steady state at a normal pressure set value, where the first pressure set value is greater than the normal pressure set value;
the decrease module 402 configured to decrease a pressure value of the urea pump to a second pressure set point when the urea pump is in a steady state at the first pressure set point, wherein the second pressure set point is less than the normal pressure set point;
the obtaining and determining module 403 is configured to obtain a current pressure value of the target system and a sampling pressure value at a corresponding time point after the adjustment is completed, and determine whether the target system leaks according to a difference between the current pressure value and the sampling pressure value.
The invention discloses a urea leakage detection device, which comprises: when detecting that a urea pump of a target system is in a stable state under a normal pressure set value, increasing the pressure value of the urea pump to a first pressure set value, wherein the first pressure set value is larger than the normal pressure set value; when the urea pump is in a steady state at the first pressure set point, reducing the pressure value of the urea pump to a second pressure set point, wherein the second pressure set point is less than the normal pressure set point; and after the adjustment is finished, acquiring a current pressure value of the target system and a sampling pressure value of a corresponding time point, and determining whether the target system leaks or not according to a difference value between the current pressure value and the sampling pressure value. According to the detection device, in the operation process of the system, whether urea leaks in the system can be detected without adding extra detection equipment, and waste caused by urea leakage is avoided.
In an embodiment of the present invention, the detection apparatus further includes:
the device comprises a detection module and a prompt module.
Wherein:
the detection module is used for detecting whether the urea pump has a fault;
and the prompting module is used for sending a fault instruction to prompt the fault of the urea pump if the fault instruction is positive.
In an embodiment of the present invention, the detection apparatus further includes: and a storage module.
Wherein:
the storage module is used for storing the current pressure value and the sampling pressure value.
In this embodiment of the present invention, the obtaining and determining module 403 includes:
the device comprises a first acquisition unit, a first calculation unit, a first comparison and judgment unit and a first judgment unit.
Wherein:
the first obtaining unit is used for obtaining the sampling pressure value of the urea pump at the time point at a first time interval preset after the current pressure value is obtained;
the first calculating unit is used for calculating a pressure difference value between the current pressure value and the sampling pressure value;
the first comparison and judgment unit is used for comparing the pressure difference value with a preset pressure difference threshold value and judging whether the pressure difference value is larger than the preset pressure difference threshold value or not;
the first determination unit is used for determining that the target system has leakage if the target system is in a leakage state, or determining that the target system does not have leakage if the target system is not in a leakage state.
In this embodiment of the present invention, the obtaining and determining module 403 includes:
the device comprises a second acquisition unit, a second calculation unit, a second comparison and judgment unit and a second judgment unit.
Wherein:
the second obtaining unit is configured to obtain the sampling pressure value every preset second time length after obtaining the current pressure value;
the second calculating unit is used for calculating pressure change rates between adjacent pressure values and average pressure change rates of all the pressure change rates when the number of the sampling pressure values or the total duration of intervals meets the corresponding threshold requirements;
the second comparison and judgment unit is used for comparing the average pressure change rate with a preset pressure change rate threshold value and judging whether the average pressure change rate is larger than the preset pressure change rate threshold value or not;
the second determination unit is configured to determine that the target system has a leak if the target system has the leak, or determine that the target system does not have the leak if the target system has the leak.
It should be noted that, in the present specification, the embodiments are all described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments may be referred to each other. For the device-like embodiment, since it is basically similar to the method embodiment, the description is simple, and for the relevant points, reference may be made to the partial description of the method embodiment.
Finally, it should also be noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
For convenience of description, the above devices are described as being divided into various units by function, and are described separately. Of course, the functions of the units may be implemented in the same software and/or hardware or in a plurality of software and/or hardware when implementing the invention.
From the above description of the embodiments, it is clear to those skilled in the art that the present invention can be implemented by software plus necessary general hardware platform. Based on such understanding, the technical solutions of the present invention may be embodied in the form of a software product, which may be stored in a storage medium, such as ROM/RAM, magnetic disk, optical disk, etc., and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute the method according to the embodiments or some parts of the embodiments.
The method and the device for detecting urea leakage provided by the invention are described in detail above, and the principle and the implementation mode of the invention are explained in the text by applying specific examples, and the description of the above examples is only used for helping to understand the method and the core idea of the invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present invention.
Claims (10)
1. A method for leak detection of urea, comprising:
when detecting that a urea pump of a target system is in a stable state under a normal pressure set value, increasing the pressure value of the urea pump to a first pressure set value, wherein the first pressure set value is larger than the normal pressure set value;
when the urea pump is in a steady state at the first pressure set point, reducing the pressure value of the urea pump to a second pressure set point, wherein the second pressure set point is less than the normal pressure set point;
and after the adjustment is finished, acquiring a current pressure value of the target system and a sampling pressure value of a corresponding time point, and determining whether the target system leaks or not according to a difference value between the current pressure value and the sampling pressure value.
2. The method of claim 1, further comprising:
detecting whether the urea pump has a fault;
and if so, sending a fault instruction to prompt the fault of the urea pump.
3. The method of claim 1, further comprising:
and storing the current pressure value and the sampling pressure value.
4. The method of claim 1, wherein after the adjustment is completed, obtaining a current pressure value of the target system and a sampling pressure value at a corresponding time point, and determining whether the target system leaks according to a difference between the current pressure value and the sampling pressure value comprises:
acquiring a sampling pressure value of the urea pump at the time point at a preset first time interval after acquiring the current pressure value;
calculating a pressure difference value between the current pressure value and the sampling pressure value;
comparing the pressure difference value with a preset pressure difference threshold value, and judging whether the pressure difference value is greater than the preset pressure difference threshold value;
if yes, judging that the target system has leakage, or if not, judging that the target system does not have leakage.
5. The method of claim 1, wherein after the adjustment is completed, obtaining a current pressure value of the target system and a sampling pressure value at a corresponding time point, and determining whether the target system leaks according to a difference between the current pressure value and the sampling pressure value comprises:
acquiring the sampling pressure value at a preset second time interval after acquiring the current pressure value;
when the number of the sampling pressure values or the total time of the intervals meets the corresponding threshold value requirement, calculating the pressure change rate between the adjacent pressure values and the average pressure change rate of each pressure change rate;
comparing the average pressure change rate with a preset pressure change rate threshold value, and judging whether the average pressure change rate is greater than the preset pressure change rate threshold value;
if yes, judging that the target system has leakage, or if not, judging that the target system does not have leakage.
6. A urea leak detection device, comprising:
the system comprises an increasing module, a judging module and a control module, wherein the increasing module is used for increasing the pressure value of a urea pump of a target system to a first pressure set value when the urea pump is detected to be in a stable state under a normal pressure set value, and the first pressure set value is larger than the normal pressure set value;
the reducing module is used for reducing the pressure value of the urea pump to a second pressure set value when the urea pump is in a stable state under the first pressure set value, wherein the second pressure set value is smaller than the normal pressure set value;
and the acquisition determining module is used for acquiring the current pressure value of the target system and the sampling pressure value of the corresponding time point after the adjustment is finished, and determining whether the target system leaks or not according to the difference value between the current pressure value and the sampling pressure value.
7. The apparatus of claim 6, further comprising:
the detection module is used for detecting whether the urea pump has a fault;
and the prompting module is used for sending a fault instruction to prompt the fault of the urea pump if the fault instruction is positive.
8. The apparatus of claim 6, further comprising:
and the storage module is used for storing the current pressure value and the sampling pressure value.
9. The apparatus of claim 6, wherein the acquisition determination module comprises:
the first obtaining unit is used for obtaining the sampling pressure value of the urea pump at the time point at a first time interval preset after the current pressure value is obtained;
the first calculation unit is used for calculating a pressure difference value between the current pressure value and the sampling pressure value;
the first comparison and judgment unit is used for comparing the pressure difference value with a preset pressure difference threshold value and judging whether the pressure difference value is larger than the preset pressure difference threshold value or not;
the first judging unit is used for judging that the target system has leakage if the target system has leakage, or judging that the target system does not have leakage if the target system does not have leakage.
10. The apparatus of claim 6, wherein the acquisition determination module comprises:
the second obtaining unit is used for obtaining the sampling pressure value at a preset second time interval after the current pressure value is obtained;
the second calculation unit is used for calculating the pressure change rate between the adjacent pressure values and the average pressure change rate of each pressure change rate when the number of the sampling pressure values or the total duration of the intervals meets the corresponding threshold requirement;
the second comparison and judgment unit is used for comparing the average pressure change rate with a preset pressure change rate threshold value and judging whether the average pressure change rate is larger than the preset pressure change rate threshold value or not;
and the second judging unit is used for judging that the target system has leakage if the target system has leakage, or judging that the target system does not have leakage if the target system has no leakage.
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