CN109252923B - Air-assisted urea injection system and lower electric blowing method thereof - Google Patents
Air-assisted urea injection system and lower electric blowing method thereof Download PDFInfo
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- CN109252923B CN109252923B CN201811085145.0A CN201811085145A CN109252923B CN 109252923 B CN109252923 B CN 109252923B CN 201811085145 A CN201811085145 A CN 201811085145A CN 109252923 B CN109252923 B CN 109252923B
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
- F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
- F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
- F01N3/18—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control
- F01N3/20—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control specially adapted for catalytic conversion ; Methods of operation or control of catalytic converters
- F01N3/2066—Selective catalytic reduction [SCR]
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- 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
- F01N3/2093—Periodically blowing a gas through the converter, e.g. in a direction opposite to exhaust gas flow or by reversing exhaust gas flow direction
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
- F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
- F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
- F01N3/24—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 constructional aspects of converting apparatus
- F01N3/28—Construction of catalytic reactors
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N2610/00—Adding substances to exhaust gases
- F01N2610/02—Adding substances to exhaust gases the substance being ammonia or urea
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N2610/00—Adding substances to exhaust gases
- F01N2610/14—Arrangements for the supply of substances, e.g. conduits
- F01N2610/1406—Storage means for substances, e.g. tanks or reservoirs
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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
- F01N2610/1473—Overflow or return means for the substances, e.g. conduits or valves for the return path
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/10—Internal combustion engine [ICE] based vehicles
- Y02T10/12—Improving ICE efficiencies
Abstract
According to the air-assisted urea injection system and the power-down blowing method thereof, under a low-temperature environment, after power down, not only are urea in a urea pump mixing cavity, an injection pressure pipe and a nozzle blown, but also urea in a urea pump flow passage and a liquid return pipe is blown back to a urea box, so that the risk of frost cracking of the urea pump is reduced, and the failure rate of the urea pump is further reduced. Furthermore, the time of the first time period, the second time period and the third time period is optimized, so that when urea is blown back to the urea box, the urea cannot overflow through the air holes due to pressure difference, and the failure rate of the urea box is reduced.
Description
Technical Field
The invention relates to the technical field of Selective Catalytic Reduction (SCR), in particular to an air-assisted urea injection system and a lower electric blowing method thereof.
Background
At present, the most mainstream of the diesel engine tail gas aftertreatment technology is SCR (selective catalytic reduction), and the main principle of the SCR technology is that urea is sprayed into the tail gas, the urea is hydrolyzed into ammonia gas, and the ammonia gas reacts with nitric oxide in the tail gas under the action of a catalyst to reduce the ammonia gas into nitrogen which is harmless to the environment.
The injection system is a core component in the SCR system. The main stream injection system includes a non-air-assisted urea injection system and an air-assisted urea injection system. Compared with a non-air-assisted urea injection system, the air-assisted urea injection system has the advantages of good atomization effect and the like. However, the existing air-assisted urea injection system only purges urea at a urea pump mixing cavity, an injection pressure pipe and a nozzle after being powered off; and the inside runner of urea pump and return liquid pipe do not have and sweep, lead to very easily appearing the risk that the urea pump freezes in winter.
Disclosure of Invention
In view of this, the present invention provides an air-assisted urea injection system and a lower electric purge method thereof, aiming to achieve the purpose of reducing the failure rate of a urea pump.
In order to achieve the above object, the following solutions are proposed:
an air-assisted urea injection system comprising: the device comprises a urea box, a liquid inlet cavity inlet one-way valve, a liquid inlet cavity outlet one-way valve, a liquid inlet cavity, an electromagnetic coil, a metering cavity inlet one-way valve, a metering cavity outlet one-way valve, a metering cavity, a liquid return electromagnetic valve, a liquid discharge electromagnetic valve, an air electromagnetic valve, a mixing cavity, a jet orifice, a liquid return port, a liquid return pressure valve, a pressure stabilizing valve, a two-position two-way electromagnetic valve and an air inlet;
the liquid inlet and the liquid return port are both connected with the urea box;
the liquid inlet, the liquid inlet cavity inlet one-way valve, the liquid inlet cavity outlet one-way valve, the metering cavity inlet one-way valve, the metering cavity outlet one-way valve, the liquid discharge electromagnetic valve, the mixing cavity and the jet orifice are sequentially connected through a pipeline to form a urea injection loop;
the liquid return port, the liquid return electromagnetic valve and a pipeline between the liquid inlet cavity outlet one-way valve and the metering cavity inlet one-way valve are sequentially connected through a pipeline to form a first urea liquid return loop;
the liquid return port, the liquid return pressure valve, and a pipeline between the metering cavity outlet one-way valve and the liquid discharge electromagnetic valve are sequentially connected through pipelines to form a second urea liquid return loop;
the air inlet, the pressure stabilizing valve, the air electromagnetic valve, the mixing cavity, the two-position two-way electromagnetic valve and a pipeline between the liquid inlet cavity outlet one-way valve and the metering cavity inlet one-way valve are sequentially connected through pipelines to form a normal-temperature purging loop;
the liquid return pressure valve and a pipeline between the pressure stabilizing valve and the air electromagnetic valve are connected through a pipeline.
Optionally, the air-assisted urea injection system further comprises: and the pressure sensor is arranged on a pipeline between the metering cavity outlet one-way valve and the liquid discharge electromagnetic valve.
The lower electric blowing method of the air-assisted urea injection system comprises the following steps:
when an electric signal under a vehicle is received, acquiring a temperature signal, wherein the temperature signal is an environment temperature signal or a urea pump temperature signal;
judging whether the temperature signal is smaller than a temperature threshold value, if so, controlling the liquid discharge electromagnetic valve to be opened and controlling the air electromagnetic valve to be opened, keeping the first time period, and if not, executing normal-temperature purging;
suspending purging for a second period of time at the end of the first period of time;
when the second time period is over, controlling the electromagnetic coil to be opened and controlling the liquid return electromagnetic valve to be opened, and keeping the third time period;
and when the third time period is over, adding 1 to the current cycle number, judging whether the current cycle number is greater than a preset first cycle threshold value, if not, continuing to execute the steps of controlling the liquid discharge electromagnetic valve to be opened and controlling the air electromagnetic valve to be opened, keeping the first time period, if so, resetting the current cycle number and stopping purging.
Optionally, the third time period is less than the first time period, and the first time period is less than the second time period.
Optionally, the first time period is 0.4S, the second time period is 3S, and the third time period is 0.2S.
Optionally, the normal-temperature purging includes:
controlling the liquid discharge solenoid valve to be opened and controlling the air solenoid valve to be opened, and keeping the liquid discharge solenoid valve for a fourth time period;
at the end of the fourth time period, the purge is stopped.
Optionally, the normal-temperature purging includes:
controlling the liquid discharge electromagnetic valve to be opened and controlling the air electromagnetic valve to be opened, and keeping for a fifth time period;
suspending purging for a sixth time period at the end of the fifth time period;
and when the sixth time period is finished, adding 1 to the current cycle number, judging whether the current cycle number is greater than a preset second cycle threshold value, if not, continuing to execute the steps of controlling the liquid discharge electromagnetic valve to be opened and controlling the air electromagnetic valve to be opened, keeping the fifth time period, if so, resetting the current cycle number and stopping purging.
Compared with the prior art, the technical scheme of the invention has the following advantages:
according to the air-assisted urea injection system and the lower electric blowing method thereof, under the low-temperature environment, urea at a urea pump mixing cavity, an injection pressure pipe and a nozzle is blown after power is turned off, urea in a urea pump flow channel and a liquid return pipe is blown back to a urea box, the risk of frost cracking of the urea pump is reduced, and the failure rate of the urea pump is further reduced.
Furthermore, the time of the first time period, the second time period and the third time period is optimized, so that when urea is blown back to the urea box, the urea cannot overflow through the air holes due to pressure difference, and the failure rate of the urea box is reduced.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.
FIG. 1 is a schematic diagram of an air-assisted urea injection system according to an embodiment of the present invention;
FIG. 2 is a flowchart of a method for electrically purging an air-assisted urea injection system according to an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Air-assisted urea injection system: including urea pumps, nozzles and compressed air filters, which function to meter and inject urea, is a device that injects urea, i.e., a reductant, into a reactor in specified amounts.
The present embodiment provides an air-assisted urea injection system, as shown in fig. 1, comprising: the device comprises a urea box 11, a liquid inlet 12, a liquid inlet cavity inlet one-way valve 13, a liquid inlet cavity outlet one-way valve 14, a liquid inlet cavity 15, an electromagnetic coil 16, a metering cavity inlet one-way valve 17, a metering cavity outlet one-way valve 18, a metering cavity 19, a liquid return electromagnetic valve 20, a liquid discharge electromagnetic valve 21, an air electromagnetic valve 22, a mixing cavity 23, a jet orifice 24, a liquid return port 25, a liquid return pressure valve 26, a pressure stabilizing valve 27, a two-position two-way electromagnetic valve 28 and an air inlet 29.
The liquid inlet 12 and the liquid return port 25 are both connected with the urea tank 11. The liquid inlet 12, the liquid inlet cavity inlet one-way valve 13, the liquid inlet cavity 15, the liquid inlet cavity outlet one-way valve 14, the metering cavity inlet one-way valve 17, the metering cavity 19, the metering cavity outlet one-way valve 18, the liquid discharge electromagnetic valve 21, the mixing cavity 23 and the jet orifice 24 are connected in sequence through pipelines to form a urea injection loop.
The liquid return port 25, the liquid return electromagnetic valve 20 and the pipeline between the liquid inlet cavity outlet one-way valve 14 and the metering cavity inlet one-way valve 17 are sequentially connected through the pipeline to form a first urea liquid return loop; and the liquid return port 25, the liquid return pressure valve 26, and a pipeline between the metering cavity outlet one-way valve 18 and the liquid discharge electromagnetic valve 21 are sequentially connected through pipelines to form a second urea liquid return loop.
And pipelines between the air inlet 29, the pressure stabilizing valve 27, the air electromagnetic valve 22, the mixing cavity 23, the two-position two-way electromagnetic valve 28 and the liquid inlet cavity outlet one-way valve 14 and the metering cavity inlet one-way valve 17 are sequentially connected through pipelines to form a normal-temperature purging loop.
The return hydraulic pressure valve 26 and the pipeline between the pressure maintaining valve 27 and the air solenoid valve 22 are connected by pipelines.
When the air electromagnetic valve 22 is opened and the liquid discharge electromagnetic valve 21 is opened, the liquid return pressure valve 26 is closed, air enters through the air inlet 29, and then the air sequentially passes through the pressure stabilizing valve 27, the air electromagnetic valve 22, the mixing cavity 23, the two-position two-way electromagnetic valve 28, the metering cavity inlet one-way valve 17, the metering cavity 19, the metering cavity outlet one-way valve 18, the liquid discharge electromagnetic valve 21, the mixing cavity 23 and the injection port 24, so that normal-temperature blowing is realized, and urea in the mixing cavity 23 and a pipeline between the mixing cavity and the injection button 24 can be blown out.
During purging, the return hydraulic pressure valve 26 is closed due to the action of air pressure; after the air electromagnetic valve 22 is closed, namely, purging is not performed, air does not enter the pressure maintaining valve 27, so that the liquid return pressure valve 26 is opened, and urea in the metering cavity 19 can be sucked back to the urea box 11 through the liquid return pressure valve 26 and the liquid return port 25. When the liquid return electromagnetic valve 20 is opened and the electromagnetic coil 16 is opened, the volume of the liquid inlet cavity 15 and the volume of the metering cavity 19 are periodically changed, and then the urea in the liquid inlet cavity 15 and the urea in the metering cavity 19 are sucked back to the urea box 11 through the liquid return electromagnetic valve 20 and the liquid return pressure valve 26. And then realize blowing urea in urea pump runner (being the pipeline that feed liquor chamber 15, measurement chamber 19 and both are connected) and the liquid pipe that returns (being the pipeline between liquid return port 25 and the liquid return solenoid valve 20) back to urea case 11, reduced the risk that the urea pump freezes, and then reduced the fault rate of urea pump.
Alternatively, a pressure sensor may be provided in the line between the metering chamber outlet check valve 18 and the discharge solenoid valve 21.
The present implementation provides a method of lower electric purge applied to the air-assisted urea injection system shown in fig. 1, which, referring to fig. 2, may include the steps of:
s11: and acquiring a temperature signal when the vehicle off-board electric signal is received.
In this embodiment, when the vehicle key is turned to the OFF position, the electronic control unit of the vehicle sends an OFF signal, and when the electronic control unit receives the OFF signal, the temperature signal is acquired. The temperature signal is an ambient temperature signal or a urea pump temperature signal.
S12: and judging whether the acquired temperature signal is smaller than a temperature threshold value, if so, executing step S13, and if so, executing step S18.
S13: the drain control solenoid valve 21 is opened and the air solenoid valve 22 is opened and maintained for a first period of time.
Step S13 is executed, in the first time period, the liquid discharge electromagnetic valve 21 is opened, the air electromagnetic valve 22 is opened, air enters through the air inlet 29, and then the air sequentially passes through the pressure stabilizing valve 27, the air electromagnetic valve 22, the mixing cavity 23, the two-position two-way electromagnetic valve 28, the metering cavity inlet one-way valve 17, the metering cavity 19, the metering cavity outlet one-way valve 18, the liquid discharge electromagnetic valve 21, the mixing cavity 23 and the injection port 24 to purge urea in the mixing cavity 23 and a pipeline between the mixing cavity and the injection port 24.
S14: at the end of the first period, purging is suspended for a second period.
Step S14 is executed, and in the second time period, the liquid solenoid valve 21 is controlled to be closed, and the air solenoid valve 22 is controlled to be closed; after the air solenoid valve 22 is closed, the liquid return pressure valve 26 is opened, and the urea in the metering chamber 19 can be sucked back to the urea tank 11 through the liquid return pressure valve 26 and the liquid return port 25.
S15: at the end of the second period, the solenoid 16 is controlled to open and the return solenoid 20 is controlled to open for a third period.
Step S15 is executed, and during the third period, the liquid return solenoid valve 20 is opened and the solenoid is opened 16, so that the urea in the liquid inlet chamber 15 is sucked back to the urea tank 11 through the liquid return solenoid valve 20 and the liquid return port 25. It should be noted that during the third period, since the air solenoid valve 22 is still closed, the urea in the metering chamber 19 can be sucked back into the urea tank 11 through the liquid return pressure valve 26 and the liquid return port 25.
S16: and when the third time period is over, adding 1 to the current cycle number, and judging whether the current cycle number is greater than a preset first cycle threshold, if not, executing the step S13, and if so, executing the step S17.
S17: and clearing the current cycle number and stopping purging.
The purge is stopped, i.e., the return solenoid valve 20 is closed, the drain solenoid valve 21 is closed, the air solenoid valve 22 is closed, and the solenoid 16 is closed.
S18: and performing normal-temperature purging.
In this embodiment, the normal-temperature purge may include two purge methods. The first purging mode is to continue purging for a preset time, specifically, to control the liquid discharge solenoid valve 21 to open and the air solenoid valve 22 to open, and to keep the fourth time period, and to stop purging when the fourth time period ends. I.e. during a preset fourth period of time, purging is always performed to purge urea from the mixing chamber 23 and the line between the mixing chamber and the injection port 24.
Another way of purging is to purge at intervals over a preset time. Specifically, the liquid discharge electromagnetic valve 21 is controlled to be opened, and the air electromagnetic valve 22 is controlled to be opened, and the fifth time period is kept; at the end of the fifth time period, pausing the purge for a sixth time period; and when the sixth time period is finished, adding 1 to the current cycle number, judging whether the current cycle number is greater than a preset second cycle threshold value, if not, continuing to execute the steps of controlling the liquid discharge electromagnetic valve 21 to be opened and controlling the air electromagnetic valve 22 to be opened, keeping the fifth time period, if so, resetting the current cycle number and stopping purging.
When the amount of gas blown back to the urea box 11 by the urea pump air pipe is larger than the air outlet amount of the air holes of the urea box 11, negative pressure exists in the urea box 11, and urea overflows easily when the urea box 11 is full of urea. Through the experiment discovery, optimize the setting of sweeping the time, set up the third time quantum promptly and be less than first time quantum, and first time quantum is less than the second time quantum for urea in urea pump and the pipeline can sweep cleanly, and has reduced urea case 11's bleeder vent and has appeared leaking the condition of urea. Specifically, the first time period is 0.4S, the second time period is 3S, and the third time period is 0.2S.
In this document, 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.
The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other.
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.
Claims (5)
1. A method of electrogas scavenging, applied to an air-assisted urea injection system, the system comprising: the device comprises a urea box, a liquid inlet cavity inlet one-way valve, a liquid inlet cavity outlet one-way valve, a liquid inlet cavity, an electromagnetic coil, a metering cavity inlet one-way valve, a metering cavity outlet one-way valve, a metering cavity, a liquid return electromagnetic valve, a liquid discharge electromagnetic valve, an air electromagnetic valve, a mixing cavity, a jet orifice, a liquid return port, a liquid return pressure valve, a pressure stabilizing valve, a two-position two-way electromagnetic valve and an air inlet;
the liquid inlet and the liquid return port are both connected with the urea box;
the liquid inlet, the liquid inlet cavity inlet one-way valve, the liquid inlet cavity outlet one-way valve, the metering cavity inlet one-way valve, the metering cavity outlet one-way valve, the liquid discharge electromagnetic valve, the mixing cavity and the jet orifice are sequentially connected through a pipeline to form a urea injection loop;
the liquid return port, the liquid return electromagnetic valve and a pipeline between the liquid inlet cavity outlet one-way valve and the metering cavity inlet one-way valve are sequentially connected through a pipeline to form a first urea liquid return loop;
the liquid return port, the liquid return pressure valve, and a pipeline between the metering cavity outlet one-way valve and the liquid discharge electromagnetic valve are sequentially connected through pipelines to form a second urea liquid return loop;
the air inlet, the pressure stabilizing valve, the air electromagnetic valve, the mixing cavity, the two-position two-way electromagnetic valve and a pipeline between the liquid inlet cavity outlet one-way valve and the metering cavity inlet one-way valve are sequentially connected through pipelines to form a normal-temperature purging loop;
the liquid return pressure valve is connected with a pipeline between the pressure stabilizing valve and the air electromagnetic valve through a pipeline;
the method comprises the following steps:
when an electric signal under a vehicle is received, acquiring a temperature signal, wherein the temperature signal is an environment temperature signal or a urea pump temperature signal;
judging whether the temperature signal is smaller than a temperature threshold value, if so, controlling the liquid discharge electromagnetic valve to be opened and controlling the air electromagnetic valve to be opened, keeping the first time period, and if not, executing normal-temperature purging;
suspending purging for a second period of time at the end of the first period of time;
when the second time period is over, controlling the electromagnetic coil to be opened and controlling the liquid return electromagnetic valve to be opened, and keeping the third time period;
and when the third time period is over, adding 1 to the current cycle number, judging whether the current cycle number is greater than a preset first cycle threshold value, if not, continuing to execute the steps of controlling the liquid discharge electromagnetic valve to be opened and controlling the air electromagnetic valve to be opened, keeping the first time period, if so, resetting the current cycle number and stopping purging.
2. The method of claim 1, wherein the third time period is less than the first time period, and wherein the first time period is less than the second time period.
3. The method of claim 2, wherein the first time period is 0.4S, the second time period is 3S, and the third time period is 0.2S.
4. The method of claim 1, wherein the ambient temperature purge comprises:
controlling the liquid discharge solenoid valve to be opened and controlling the air solenoid valve to be opened, and keeping the liquid discharge solenoid valve for a fourth time period;
at the end of the fourth time period, the purge is stopped.
5. The method of claim 1, wherein the ambient temperature purge comprises:
controlling the liquid discharge electromagnetic valve to be opened and controlling the air electromagnetic valve to be opened, and keeping for a fifth time period;
suspending purging for a sixth time period at the end of the fifth time period;
and when the sixth time period is finished, adding 1 to the current cycle number, judging whether the current cycle number is greater than a preset second cycle threshold value, if not, continuing to execute the steps of controlling the liquid discharge electromagnetic valve to be opened and controlling the air electromagnetic valve to be opened, keeping the fifth time period, if so, resetting the current cycle number and stopping purging.
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| CN201811085145.0A CN109252923B (en) | 2018-09-18 | 2018-09-18 | Air-assisted urea injection system and lower electric blowing method thereof |
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| CN201811085145.0A CN109252923B (en) | 2018-09-18 | 2018-09-18 | Air-assisted urea injection system and lower electric blowing method thereof |
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| CN109763883B (en) * | 2019-02-11 | 2021-03-12 | 无锡威孚力达催化净化器有限责任公司 | Method, device and system for detecting ammonia gas leakage of SCR system |
| CN113107653B (en) * | 2021-04-27 | 2022-09-23 | 广西沃宾电子科技有限责任公司 | Control method of engine SCR tail gas emission post-treatment system |
| CN113356977B (en) * | 2021-07-21 | 2022-07-15 | 潍柴动力股份有限公司 | Control method of urea pump and engine aftertreatment system |
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| CN106837486A (en) * | 2016-12-27 | 2017-06-13 | 潍柴动力空气净化科技有限公司 | Gas helps formula urea injection system and gas to help formula method for urea injection control |
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| CN202100308U (en) * | 2011-06-21 | 2012-01-04 | 中国汽车工程研究院股份有限公司 | Selective catalytic reduction (SCR) system for urea solution metering injection |
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| CN205677733U (en) * | 2015-06-01 | 2016-11-09 | 卡特彼勒公司 | Purging system for engine system |
| CN106285851A (en) * | 2016-09-22 | 2017-01-04 | 凯龙高科技股份有限公司 | A kind of dosing pump fluid path blow device |
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| CN109252923A (en) | 2019-01-22 |
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