CN113944533A - Mixer, tail gas aftertreatment system and treatment method - Google Patents
Mixer, tail gas aftertreatment system and treatment method Download PDFInfo
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- CN113944533A CN113944533A CN202111193028.8A CN202111193028A CN113944533A CN 113944533 A CN113944533 A CN 113944533A CN 202111193028 A CN202111193028 A CN 202111193028A CN 113944533 A CN113944533 A CN 113944533A
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- connecting flange
- mixer
- tail gas
- exhaust
- grid
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- 238000000034 method Methods 0.000 title claims description 12
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 claims abstract description 42
- 239000004202 carbamide Substances 0.000 claims abstract description 42
- 238000010438 heat treatment Methods 0.000 claims abstract description 37
- 239000007864 aqueous solution Substances 0.000 claims abstract description 16
- 238000002156 mixing Methods 0.000 claims abstract description 10
- 238000002347 injection Methods 0.000 claims description 12
- 239000007924 injection Substances 0.000 claims description 12
- 238000009434 installation Methods 0.000 claims description 8
- 239000003054 catalyst Substances 0.000 claims description 7
- 230000003044 adaptive effect Effects 0.000 claims description 4
- 210000001503 joint Anatomy 0.000 claims description 4
- 239000012041 precatalyst Substances 0.000 claims description 4
- 238000006243 chemical reaction Methods 0.000 abstract description 9
- 239000007789 gas Substances 0.000 description 58
- OWIKHYCFFJSOEH-UHFFFAOYSA-N Isocyanic acid Chemical compound N=C=O OWIKHYCFFJSOEH-UHFFFAOYSA-N 0.000 description 15
- XLJMAIOERFSOGZ-UHFFFAOYSA-N anhydrous cyanic acid Natural products OC#N XLJMAIOERFSOGZ-UHFFFAOYSA-N 0.000 description 13
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 12
- 238000006460 hydrolysis reaction Methods 0.000 description 8
- MWUXSHHQAYIFBG-UHFFFAOYSA-N Nitric oxide Chemical compound O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 7
- 230000007062 hydrolysis Effects 0.000 description 7
- 238000001704 evaporation Methods 0.000 description 6
- 230000008020 evaporation Effects 0.000 description 6
- 238000002425 crystallisation Methods 0.000 description 4
- 230000008025 crystallization Effects 0.000 description 4
- 239000007788 liquid Substances 0.000 description 4
- 229920000642 polymer Polymers 0.000 description 4
- 238000000197 pyrolysis Methods 0.000 description 4
- 238000005903 acid hydrolysis reaction Methods 0.000 description 3
- 238000010531 catalytic reduction reaction Methods 0.000 description 3
- 238000011161 development Methods 0.000 description 3
- 238000006116 polymerization reaction Methods 0.000 description 3
- 239000000243 solution Substances 0.000 description 3
- 238000001321 HNCO Methods 0.000 description 2
- 229910021529 ammonia Inorganic materials 0.000 description 2
- 230000003197 catalytic effect Effects 0.000 description 2
- 238000011217 control strategy Methods 0.000 description 2
- 230000013011 mating Effects 0.000 description 2
- 229910000069 nitrogen hydride Inorganic materials 0.000 description 2
- 238000009834 vaporization Methods 0.000 description 2
- 230000008016 vaporization Effects 0.000 description 2
- ODUCDPQEXGNKDN-UHFFFAOYSA-N Nitrogen oxide(NO) Natural products O=N ODUCDPQEXGNKDN-UHFFFAOYSA-N 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 238000005485 electric heating Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012805 post-processing Methods 0.000 description 1
- 238000003672 processing method Methods 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- WTHDKMILWLGDKL-UHFFFAOYSA-N urea;hydrate Chemical compound O.NC(N)=O WTHDKMILWLGDKL-UHFFFAOYSA-N 0.000 description 1
Images
Classifications
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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
- F01N3/2892—Exhaust flow directors or the like, e.g. upstream of catalytic device
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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
- 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
- F01N13/008—Mounting or arrangement of exhaust sensors in or on exhaust apparatus
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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
- 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
- F01N13/009—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 having two or more separate purifying devices arranged in series
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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
- F01N3/2006—Periodically heating or cooling catalytic reactors, e.g. at cold starting or overheating
- F01N3/2013—Periodically heating or cooling catalytic reactors, e.g. at cold starting or overheating using electric or magnetic heating means
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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
- F01N3/2066—Selective catalytic reduction [SCR]
- F01N3/208—Control of selective catalytic reduction [SCR], e.g. dosing of reducing agent
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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
- F01N2240/00—Combination or association of two or more different exhaust treating devices, or of at least one such device with an auxiliary device, not covered by indexing codes F01N2230/00 or F01N2250/00, one of the devices being
- F01N2240/16—Combination or association of two or more different exhaust treating devices, or of at least one such device with an auxiliary device, not covered by indexing codes F01N2230/00 or F01N2250/00, one of the devices being an electric heater, i.e. a resistance heater
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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
- F01N2240/00—Combination or association of two or more different exhaust treating devices, or of at least one such device with an auxiliary device, not covered by indexing codes F01N2230/00 or F01N2250/00, one of the devices being
- F01N2240/20—Combination or association of two or more different exhaust treating devices, or of at least one such device with an auxiliary device, not covered by indexing codes F01N2230/00 or F01N2250/00, one of the devices being a flow director or deflector
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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
- F01N2610/10—Adding substances to exhaust gases the substance being heated, e.g. by heating tank or supply line of the added substance
- F01N2610/102—Adding substances to exhaust gases the substance being heated, e.g. by heating tank or supply line of the added substance after addition to exhaust gases, e.g. by a passively or actively heated surface in the exhaust conduit
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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
- F01N2610/10—Adding substances to exhaust gases the substance being heated, e.g. by heating tank or supply line of the added substance
- F01N2610/105—Control thereof
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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
- F01N2610/1486—Means to prevent the substance from freezing
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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
Abstract
The invention relates to a mixer, which is arranged on an exhaust pipeline of an engine and is used for fully mixing tail gas discharged by the engine and urea aqueous solution sprayed into the exhaust pipeline; it is characterized by comprising: a first connecting flange having an intake end as an exhaust gas intake passage; a second connecting flange having a discharge end as a tail gas discharge passage; the fastening piece is used for connecting the first connecting flange and the second connecting flange, so that the air inlet end and the air outlet end of the first connecting flange and the second connecting flange are coaxial and are communicated with each other; a grid heater clamped between the first connecting flange and the second connecting flange and provided with a heating grid matched with the shape of the channel, wherein the heating grid is provided with an electrifying terminal; and the tail gas turbulator is arranged in the air inlet channel of the first connecting flange. The invention improves the reaction efficiency and the operation reliability of the post-treatment system and obviously improves the tail gas emission level of the diesel engine.
Description
Technical Field
The invention relates to the technical field of automobiles, in particular to an automobile exhaust aftertreatment device and an automobile exhaust aftertreatment method.
Background
With the upgrade of national emission regulations, SCR (Selective Catalytic Reduction) is widely used in exhaust gas aftertreatment systems of heavy-duty diesel engines. In recent years, the goods transportation structure is greatly changed along with economic development, and the urban express industry of urban logistics and light cargo distribution is started, so that the whole vehicle transported in the industry is mostly in the working condition of lower level of engine load in the actual operation; with the implementation of the national PEMS (Portable Emission Measurement System) regulation, it is very important how to improve the SCR reaction efficiency of the whole vehicle under low-load working conditions and reduce the risk of SCR urea crystallization.
The Selective Catalytic Reduction (SCR) refers to a mode of diesel engine exhaust gas treatment, in which the PM emission problem of a diesel engine is solved by optimizing the in-cylinder combustion internal purification technology, and then the engine Nitrogen Oxide (NO) is reduced by an SCR post-treatment devicexAnd (4) discharging.
The mixer used in the SCR system at present is mainly used for generating turbulence only, can only improve the mixing degree of aftertreatment liquid and tail gas, cannot be used for compensating exhaust temperature and reducing the risk of urea crystallization, and cannot improve the efficiency of urea evaporation and isocyanic acid hydrolysis.
Although a scheme of wrapping a resistance wire heating device outside a mixer and an exhaust pipe is provided, the scheme can only improve the mixing degree of the aftertreatment liquid and the exhaust gas and compensate the exhaust temperature, and cannot directly improve the evaporation efficiency of the urea aqueous solution and the hydrolysis efficiency of the isocyanic acid (see the first step of urea aqueous solution evaporation and the third step of isocyanic acid hydrolysis reaction in the urea hydrolysis reaction).
The principle of urea hydrolysis: the urea aqueous solution is injected into the exhaust pipe and reacts mainly according to the following processes before decomposing into ammonia gas which reacts with nitrogen oxides:
the first step is as follows: evaporation of aqueous urea solution
NH2-CO-NH2(aqueous solution) ⇒ NH2-CO-NH2(molten liquid) + H2O (gas state)
The second step is that: pyrolysis of urea
NH2-CO-NH2 (molten liquid) ⇒ NH3 (gaseous) + HNCO (gaseous) isocyanic acid
The third step: hydrolysis of Isocyanic acid
HNCO (gaseous) + H2O (gaseous) ⇒ NH3 (gaseous) + CO2(gaseous).
The generation of the isocyanic acid polymer mainly occurs in the second step and the third step of the process, under the working conditions of small exhaust volume of a small-displacement diesel engine, small engine load and low exhaust temperature, although the temperature of the tail gas reaches the start-up temperature of the urea aqueous solution (generally set at 200-230 ℃ according to different calibration of the engine and an after-treatment system), the heat in the tail gas is not enough to support the completion of the reaction of urea pyrolysis and isocyanic acid hydrolysis, partial unhydrolyzed isocyanic acid generates polymerization reaction in an exhaust pipe and an after-treatment device, and the produced polymer has stable chemical property and is difficult to decompose again. The polymer is gathered on the inner walls of the exhaust pipe and the post-processor and further blocked, so that the airflow in the exhaust pipe is disturbed, the mixing degree of the urea aqueous solution and the tail gas is deteriorated, and the blocking process is aggravated when the incompletely pyrolyzed urea is attached to the surface of the isocyanic acid polymer.
Disclosure of Invention
The invention aims to design a mixer with heating and turbulent functions integrated with a tail gas mixer, and the mixer is configured in a tail gas after-treatment system, so that the vaporization of urea water solution and the urea hydrolysis efficiency are promoted by a set of tail gas after-treatment method, the operation condition of the existing tail gas after-treatment system is practically improved, and the tail gas emission level of a diesel engine is further improved.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows:
the mixer is arranged on an exhaust pipeline of the engine and is used for fully mixing tail gas discharged by the engine and urea aqueous solution sprayed into the exhaust pipeline; it is characterized by comprising:
a first connecting flange having an intake end as an exhaust gas intake passage;
a second connecting flange having a discharge end as a tail gas discharge passage;
the fastening piece is used for connecting the first connecting flange and the second connecting flange, so that the air inlet end and the air outlet end of the first connecting flange and the second connecting flange are coaxial and are communicated with each other;
a grid heater clamped between the first connecting flange and the second connecting flange and provided with a heating grid matched with the shape of the channel, wherein the heating grid is provided with an electrifying terminal;
and the tail gas turbulator is arranged in the air inlet channel of the first connecting flange.
The butt joint surfaces of the first connecting flange and the second connecting flange are provided with grooves, the electrifying wiring ends at two ends of the heating grid are embedded in shaft holes formed after the two flanges are closed, and the installation positions of the heating grid are limited by the adaptive installation of the electrifying wiring ends through the shaft holes.
In a second aspect, the invention further provides an exhaust gas aftertreatment system based on the mixer.
The tail gas post-treatment system comprises an exhaust pipe connected with an exhaust port of an engine and a tail gas treatment device connected with the tail end of the exhaust pipe, and is characterized in that the exhaust pipe is communicated with the tail gas treatment device through a urea injection device, a mixer and a temperature sensor in front of a catalytic converter in sequence along the tail gas passing direction;
the urea injection device is arranged at the tail end of the exhaust pipe, and the opening and closing of an injection pipeline of the urea injection device are controlled and connected by an ECU engine controller;
the gas inlet end of the mixer is connected with a gas outlet pipeline of the exhaust pipe, the gas outlet end of the mixer is connected with a gas inlet pipeline of the tail gas treatment device, a turbulator and a heating grid are arranged in the mixer, and the on-off state of the heating grid is controlled by a relay of the whole vehicle in an attracting mode;
the front temperature sensor of the catalyst is arranged on an air inlet pipeline of the tail gas treatment device and used for detecting the temperature of the tail gas and is in signal connection with an ECU engine controller.
The mixer is used for fully mixing the tail gas discharged by the engine and the urea aqueous solution sprayed into the exhaust pipe; the structure includes:
a first connecting flange having an intake end as an exhaust gas intake passage;
a second connecting flange having a discharge end as a tail gas discharge passage;
the fastening piece is used for connecting the first connecting flange and the second connecting flange, so that the air inlet end and the air outlet end of the first connecting flange and the second connecting flange are coaxial and are communicated with each other;
a grid heater clamped between the first connecting flange and the second connecting flange and provided with a heating grid matched with the shape of the channel, wherein the heating grid is provided with an electrifying terminal;
and the tail gas turbulator is arranged in the air inlet channel of the first connecting flange.
The butt joint surfaces of the first connecting flange and the second connecting flange are provided with grooves, the electrifying wiring ends at two ends of the heating grid are embedded in shaft holes formed after the two flanges are closed, and the installation positions of the heating grid are limited by the adaptive installation of the electrifying wiring ends through the shaft holes.
Finally, the invention also provides a control strategy on the basis of the tail gas aftertreatment system.
The tail gas after-treatment method is characterized by comprising the following steps:
S1: presetting a calibration temperature in a system;
s2: the ECU engine controller compares a temperature signal value T detected by a temperature sensor in front of the catalyst with a calibration temperature; if the temperature signal value T is less than the calibration temperature, executing S3; if the temperature signal value T is greater than or equal to the calibration temperature, executing S4;
s3: the ECU engine controller outputs a signal to a whole vehicle relay, and the whole vehicle relay is used for electrifying a grid in the mixer;
s4: and the ECU engine controller controls a relay of the whole vehicle to keep the grid in the mixer powered off or to power off the grid in heating.
The mixer, the tail gas post-treatment system and the treatment method provided by the invention are based on the development trend of the current light truck type and the working principle of the post-treatment system of the SCR route, combine the market problems in the current route, start from the post-treatment reaction conditions, and purposely provide the mixer scheme with the electric control heating function.
Drawings
FIG. 1: the external structure of the mixer in the first embodiment is shown schematically;
FIG. 2: the internal structure of the mixer in the first embodiment is shown schematically;
FIG. 3: the second embodiment of the post-processing system structure diagram.
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, 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.
Example one
The mixer of the embodiment is arranged on an exhaust pipeline of an engine and is used for fully mixing tail gas discharged by the engine and urea aqueous solution sprayed into the exhaust pipeline; the exhaust gas treatment device comprises a first connecting flange 4 and a second connecting flange 5 which are oppositely arranged and fixedly connected together through a bolt fastening piece 6, wherein the first connecting flange 4 is provided with an air inlet end 41, the air inlet end 41 is connected with the tail end of an exhaust pipe, the second connecting flange 5 is provided with an exhaust end 51, and the exhaust end 51 is connected into the exhaust gas treatment device. The first connecting flange 4 and the second connecting flange 5 form a main body of the mixer after being connected, and enable an air inlet end and an air outlet end of the mixer to be communicated with each other, the grating heater 2 is arranged on the mating surface of the first connecting flange 4 and the second connecting flange 5, the grating heater 2 is composed of a heating grating 21 in the middle and electrifying terminals 22 connected to two ends of the heating grating 21, the electrifying terminals 22 at two ends are in a shaft tube structure, grooves 7 which are matched to form shaft holes are respectively arranged on the mating surface of the first connecting flange 4 and the second connecting flange 5, and the grating heater 2 is clamped between the two flanges through the electrifying terminals 22 at two ends. An exhaust gas turbulator 5 is arranged in the air inlet channel of the first connecting flange 4, the exhaust gas turbulator 5 adopts an industry conventional structural form capable of generating a turbulent flow function, and the shape of the exhaust gas turbulator 5 is matched with the air inlet channel of the first connecting flange 4.
In the embodiment, the heating grid and the turbulator are integrated in the mixer, so that the turbulent heating function of the mixer on the tail gas is realized.
Example two
Based on the mixer structure of the first embodiment, the present embodiment provides an exhaust gas after-treatment system, and the structure of the treatment system includes an engine exhaust port 11, an ECU engine controller 12, a vehicle relay 13, an exhaust pipe 14, a urea injection device 15, a mixer 16, a pre-catalyst temperature sensor 17, and an exhaust gas treatment device 18. The air inlet end of the exhaust pipe 14 is connected with an engine exhaust port 11, the exhaust end of the exhaust pipe 14 is connected with a tail gas treatment device 18 through a mixer 16, a urea injection device 15 is further arranged at the tail end of the exhaust pipe 14 and the front end of the mixer 16, and the opening and closing of an injection pipeline of the urea injection device 15 are controlled by an ECU engine controller 12; a pre-catalyst temperature sensor 17 is mounted on an air inlet pipeline of the exhaust gas treatment device 18 at the tail end of the mixer 16, and the pre-catalyst temperature sensor 17 is connected with the ECU engine controller 12 through signals and used for transmitting detected exhaust gas temperature signals to the ECU engine controller 12. In addition, a turbulator and a heating grid are arranged in the mixer 16, and the on-off state of the heating grid is controlled by the actuation of a whole vehicle relay. See example one for the structure of the mixer 16.
EXAMPLE III
The embodiment provides an exhaust gas aftertreatment method based on the system of the second embodiment, which comprises the following steps:
s1: presetting a calibration temperature in a system;
s2: the ECU engine controller compares a temperature signal value T detected by a temperature sensor in front of the catalyst with a calibration temperature; if the temperature signal value T is less than the calibration temperature, executing S3; if the temperature signal value T is greater than or equal to the calibration temperature, executing S4;
s3: the ECU engine controller outputs a signal to a whole vehicle relay, and the whole vehicle relay is used for electrifying a grid in the mixer;
s4: and the ECU engine controller controls a relay of the whole vehicle to keep the grid in the mixer powered off or to power off the grid in heating.
The control strategy and principle analysis of the processing method is as follows:
when the diesel engine runs at a low load and the exhaust temperature just reaches the urea spraying starting temperature, in order to solve the problems that the exhaust temperature is low, the urea hydrolysis is slow and the aftertreatment reaction efficiency is low at the moment, the ECU can output a whole vehicle relay signal according to the comparison of a temperature signal value T detected by a temperature sensor in front of the catalyst and a calibrated temperature value, and the relay controls a grid integrated in the mixer to start a heater to heat tail gas.
When the running working condition of the engine is improved, the engine is under higher load, and the exhaust temperature is higher (the exhaust temperature needs to be compared and judged according to the engine bench test calibration value), the ECU can compare the temperature signal value T detected by the temperature sensor in front of the catalytic converter with the calibration temperature value, and output a whole vehicle relay signal, and the relay controls the grid heater integrated in the mixer to stop heating the tail gas, so that the energy-saving purpose is achieved.
The mixer not only realizes the function of heating the tail gas and promotes the efficiency of post-treatment reaction, but also can greatly accelerate the evaporation process of the urea aqueous solution described in the section 5.1 after the urea aqueous solution contacts the heated grating, promote the hydrolysis of the urea and the pyrolysis of isocyanic acid and improve the efficiency of generating ammonia gas by the urea reaction; the tail gas turbulator integrated in the mixer can enable the tail gas and the ammonia gas to be fully mixed before reaching the aftertreatment catalyst carrier, so that the reaction efficiency of the ammonia gas and nitrogen oxides NOX in the tail gas is improved.
At present of rapid development of express logistics industry, the proportion of low-speed and low-density goods transportation types in urban areas is more and more large, a diesel-powered vehicle engine running in the industry is always in a low-load running working condition, and the requirements and challenges on a post-treatment system of an SCR (selective catalytic reduction) route are high.
1) The mixer with the integrated grid heating can compensate exhaust temperature through electric heating under the low-load working condition, increase exhaust temperature, accelerate urea evaporation and isocyanic acid pyrolysis, reduce urea crystallization and isocyanic acid polymerization, and the contact of the surface of the heated grid and a urea aqueous solution can greatly improve the vaporization of the urea aqueous solution and the reaction efficiency of urea hydrolysis, and reduce the risk of system blockage of a post-treatment system caused by urea crystallization and isocyanic acid polymerization.
2) The mixer of the integrated tail gas turbulator can obviously improve the mixing degree of ammonia and tail gas, and after the device is applied, the original length of the ammonia diffusion pipe of the after-treatment device can be properly cut short when the after-treatment device is arranged, so that the arrangement is more compact, and the system can be conveniently installed on a vehicle model with smaller wheel base and length.
In summary, although the present invention has been described with reference to the preferred embodiments, it should be understood that various changes and modifications can be made by those skilled in the art without departing from the spirit and scope of the invention.
Claims (6)
1. The mixer is arranged on an exhaust pipeline of the engine and is used for fully mixing tail gas discharged by the engine and urea aqueous solution sprayed into the exhaust pipeline; it is characterized by comprising:
A first connecting flange having an intake end as an exhaust gas intake passage;
a second connecting flange having a discharge end as a tail gas discharge passage;
the fastening piece is used for connecting the first connecting flange and the second connecting flange, so that the air inlet end and the air outlet end of the first connecting flange and the second connecting flange are coaxial and are communicated with each other;
a grid heater clamped between the first connecting flange and the second connecting flange and provided with a heating grid matched with the shape of the channel, wherein the heating grid is provided with an electrifying terminal;
and the tail gas turbulator is arranged in the air inlet channel of the first connecting flange.
2. The mixer of claim 1,
the butt joint surfaces of the first connecting flange and the second connecting flange are provided with grooves, the electrifying wiring ends at two ends of the heating grid are embedded in shaft holes formed after the two flanges are closed, and the installation positions of the heating grid are limited by the adaptive installation of the electrifying wiring ends through the shaft holes.
3. An exhaust gas after-treatment system with a heater according to claims 1-2, comprising an exhaust pipe connected to an exhaust port of the engine, and an exhaust gas treatment device connected to an end of the exhaust pipe, wherein the exhaust pipe is connected to the exhaust gas treatment device via a urea injection device, a mixer, and a pre-catalyst temperature sensor in sequence along a direction of travel of the exhaust gas;
The urea injection device is arranged at the tail end of the exhaust pipe, and the opening and closing of an injection pipeline of the urea injection device are controlled and connected by an ECU engine controller;
the gas inlet end of the mixer is connected with a gas outlet pipeline of the exhaust pipe, the gas outlet end of the mixer is connected with a gas inlet pipeline of the tail gas treatment device, a turbulator and a heating grid are arranged in the mixer, and the on-off state of the heating grid is controlled by a relay of the whole vehicle in an attracting mode;
the front temperature sensor of the catalyst is arranged on an air inlet pipeline of the tail gas treatment device and used for detecting the temperature of the tail gas and is in signal connection with an ECU engine controller.
4. The exhaust aftertreatment system of claim 3,
the mixer is used for fully mixing the tail gas discharged by the engine and the urea aqueous solution sprayed into the exhaust pipe; the structure includes:
a first connecting flange having an intake end as an exhaust gas intake passage;
a second connecting flange having a discharge end as a tail gas discharge passage;
the fastening piece is used for connecting the first connecting flange and the second connecting flange, so that the air inlet end and the air outlet end of the first connecting flange and the second connecting flange are coaxial and are communicated with each other;
a grid heater clamped between the first connecting flange and the second connecting flange and provided with a heating grid matched with the shape of the channel, wherein the heating grid is provided with an electrifying terminal;
And the tail gas turbulator is arranged in the air inlet channel of the first connecting flange.
5. The exhaust aftertreatment system of claim 4,
the butt joint surfaces of the first connecting flange and the second connecting flange are provided with grooves, the electrifying wiring ends at two ends of the heating grid are embedded in shaft holes formed after the two flanges are closed, and the installation positions of the heating grid are limited by the adaptive installation of the electrifying wiring ends through the shaft holes.
6. The exhaust gas after-treatment method implemented according to claims 3 to 5, characterized by comprising the steps of:
s1: presetting a calibration temperature in a system;
s2: the ECU engine controller compares a temperature signal value T detected by a temperature sensor in front of the catalyst with a calibration temperature; if the temperature signal value T is less than the calibration temperature, executing S3; if the temperature signal value T is greater than or equal to the calibration temperature, executing S4;
s3: the ECU engine controller outputs a signal to a whole vehicle relay, and the whole vehicle relay is used for electrifying a grid in the mixer;
s4: and the ECU engine controller controls a relay of the whole vehicle to keep the grid in the mixer powered off or to power off the grid in heating.
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB342463A (en) * | 1928-12-17 | 1931-02-05 | Hans Katz | |
| KR950008923A (en) * | 1993-09-13 | 1995-04-19 | 박세창 | Automobile Exhaust Purifier |
| CN104279026A (en) * | 2014-09-10 | 2015-01-14 | 艾蓝腾新材料科技(上海)有限公司 | Motor vehicle tail gas aftertreatment system, filtering device of motor vehicle tail gas aftertreatment system and manufacturing method of filtering device |
| CN206338105U (en) * | 2016-12-19 | 2017-07-18 | 吉林省众鑫汽车装备有限公司 | A kind of solid-state SCR system reducer feeding device |
| CN213478438U (en) * | 2020-09-24 | 2021-06-18 | 北汽福田汽车股份有限公司 | Mixer, aftertreatment system and vehicle |
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2021
- 2021-10-13 CN CN202111193028.8A patent/CN113944533A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB342463A (en) * | 1928-12-17 | 1931-02-05 | Hans Katz | |
| KR950008923A (en) * | 1993-09-13 | 1995-04-19 | 박세창 | Automobile Exhaust Purifier |
| CN104279026A (en) * | 2014-09-10 | 2015-01-14 | 艾蓝腾新材料科技(上海)有限公司 | Motor vehicle tail gas aftertreatment system, filtering device of motor vehicle tail gas aftertreatment system and manufacturing method of filtering device |
| CN206338105U (en) * | 2016-12-19 | 2017-07-18 | 吉林省众鑫汽车装备有限公司 | A kind of solid-state SCR system reducer feeding device |
| CN213478438U (en) * | 2020-09-24 | 2021-06-18 | 北汽福田汽车股份有限公司 | Mixer, aftertreatment system and vehicle |
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