KR20130013487A - Selective catalytic reduction - Google Patents

Selective catalytic reduction Download PDF

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Publication number
KR20130013487A
KR20130013487A KR1020110075165A KR20110075165A KR20130013487A KR 20130013487 A KR20130013487 A KR 20130013487A KR 1020110075165 A KR1020110075165 A KR 1020110075165A KR 20110075165 A KR20110075165 A KR 20110075165A KR 20130013487 A KR20130013487 A KR 20130013487A
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KR
South Korea
Prior art keywords
urea
injection nozzle
line
catalytic reduction
selective catalytic
Prior art date
Application number
KR1020110075165A
Other languages
Korean (ko)
Inventor
조병룡
신재석
Original Assignee
현대자동차주식회사
기아자동차주식회사
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Application filed by 현대자동차주식회사, 기아자동차주식회사 filed Critical 현대자동차주식회사
Priority to KR1020110075165A priority Critical patent/KR20130013487A/en
Publication of KR20130013487A publication Critical patent/KR20130013487A/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/92—Chemical or biological purification of waste gases of engine exhaust gases
    • B01D53/94—Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
    • 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
    • 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]
    • 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
    • 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
    • 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
    • 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
    • F01N2610/1426—Filtration means
    • 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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  • 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)
  • Biomedical Technology (AREA)
  • General Chemical & Material Sciences (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Analytical Chemistry (AREA)
  • Environmental & Geological Engineering (AREA)
  • Exhaust Gas After Treatment (AREA)
  • Exhaust Gas Treatment By Means Of Catalyst (AREA)

Abstract

PURPOSE: A selective catalytic reduction system is provided to prevent a urea injection nozzle from being contaminated as urea is not crystallized at the inlet of an injection nozzle. CONSTITUTION: A selective catalytic reduction system includes a urea tank, a supply module, a urea injection nozzle(20), and a horizontal part(44). The supply module supplies urea to the urea tank. The urea injection nozzle injects the urea to the leading end of selective catalytic reduction. A part of a urea line is formed under the lowest horizontal line of the urea in the urea injection nozzle. The urea line comprises a lower part(42) at a connection part with the urea injection nozzle. The urea injection nozzle is mounted on the leading end of the selective catalytic reduction.

Description

Selective Catalytic Reduction System {SELECTIVE CATALYTIC REDUCTION}

The present invention relates to a selective catalytic reduction system, and more particularly to a selective catalytic reduction system to improve the layout of the urea line so as not to block the inlet of the urea injection nozzle.

In general, the exhaust gas discharged from the engine through the exhaust manifold is guided and purified by a catalytic converter formed in the middle of the exhaust pipe, and the noise is attenuated while passing through the muffler and then discharged into the atmosphere through the exhaust pipe. The catalytic converter treats contaminants such as NOx contained in the exhaust gas. Selective Catalytic Reduction (SCR), one of the catalytic converters, purifies the nitrogen oxides (NOx) contained in the exhaust gas, and as a reducing agent urea (Area), ammonia (Ammonia), carbon monoxide and hydrocarbons (Hydrocarbon, HC) and the like are used.

When the reducing agent is supplied to the exhaust gas, the nitrogen oxide contained in the exhaust gas is reduced to nitrogen through an oxidation-reduction reaction with the reducing agent.

3 is a schematic diagram of a general SCR system, illustrating a selective catalytic reduction system using urea as a reducing agent.

As shown in FIG. 2, the urea tank 60 in which the urea 62 is stored, the supply module 50 for supplying the urea in the urea tank 60 to the urea injection nozzle 20, the supply module ( Urea injection nozzle 20 for supplying urea 62 supplied from 50 to the selective reduction catalyst. The urea 62 passes through the filter 52 and is supplied to the exhaust pipe 10, which is the front end of the SCR catalyst 12. This is supplied while the amount of urea 62 is controlled by a Dosing Control Unit (DCU) 25.

In addition, the temperature of the urea 62 is measured by the temperature sensor 15 or the temperature of the exhaust gas after passing through the SCR catalyst 12 is measured.

The selective reduction catalyst device recovers the urea remaining in the system back to the urea tank 60 after the key off of the vehicle, which is referred to as after run.

That is, when the selective catalytic reduction apparatus is normally operated, the urea moves to the urea injection nozzle 20 through the urea tank 60 and the supply module 50, but moves in the reverse order during the after-run operation.

However, although the inlet of the urea injection nozzle 20 should be open during the after-run operation, the urea residue may crystallize and block the inlet of the urea injection nozzle 20.

Figure 6 shows a conventional urea injection nozzle 20 and urea line 30, the urea line 30 connected to the urea injection nozzle 20 is formed upward to the urea line during the after-run operation This is a phenomenon that occurs because excessive negative pressure is formed in 30 so that urea flows backward.

That is, even if the urea is recovered by the normal operation of the after run, the urea line 30 is mounted upward of the urea injection nozzle 20 so that the urea is not completely recovered and remains at some point of the urea line 30. When the urea line 30 is pressurized to 9 to 10 bar, the remaining urea is in contact with the urea injection nozzle 20 and crystallized by high-temperature exhaust gas, thereby preventing the inlet of the urea injection nozzle.

Embodiments of the present invention seek to provide a selective catalytic reduction system that does not block the inlet of the urea injection nozzle during after run operation.

In addition, an embodiment of the present invention is to provide a selective catalytic reduction system equipped with a spray nozzle to inject the urea up.

In one or more embodiments of the present invention, an optional catalyst comprising a urea tank, a supply module for supplying urea in the urea tank, and a urea injection nozzle for injecting urea supplied from the supply module to the front of the selective reduction catalyst. In the reduction system, there may be provided a selective catalytic reduction system comprising a horizontal portion of the urea line for supplying the urea from the supply module to the urea injection nozzle is formed below the lowest horizontal line of the urea inside the urea injection nozzle.

In one or more embodiments of the present invention, the urea line has a downward portion formed at a portion connected to the urea injection nozzle.

In one or more embodiments of the present invention, an optional catalyst comprising a urea tank, a supply module for supplying urea in the urea tank, and a urea injection nozzle for injecting urea supplied from the supply module at the front end of selective catalytic reduction. In the reduction system, the urea injection nozzle may be provided in the selective catalytic reduction system, characterized in that mounted to the front end of the selective reduction catalyst to enable the injection to the selective reduction catalyst.

Embodiments of the present invention may prevent the inlet of the urea spray nozzles from clogging by lowering a portion of the urea line when recovering urea in an after-run operation.

In addition, embodiments of the present invention can prevent contamination of the urea injection nozzle because the urea remaining during urea supply after the after run operation is not crystallized at the inlet of the urea injection nozzle.

1 illustrates a urea spray nozzle portion of an SCR system in accordance with an embodiment of the present invention.
2 is a cross-sectional view showing a different mounting angle of the urea injection nozzle according to the embodiment of the present invention.
3 is a configuration diagram of a general SCR system.
4 is a schematic diagram of an SCR system in normal injection and after run mode.
Figure 5 shows the pressure change in the urea line during after run operation.
6 is a sectional view of a urea spray nozzle mounted on a conventional exhaust pipe.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings so that those skilled in the art to which the present invention pertains can easily carry out the same reference numerals for the same components as in the prior art. Use

It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to be illustrative of the invention, and are not intended to limit the scope of the inventions. I will do it.

According to an exemplary embodiment of the present invention, the shape of the urea line 40 is changed to prevent the inlet of the urea injection nozzle 20 from being blocked after performing the after run function. The after run function is key off. After the urea line 40 and the pump 56 refers to the function to empty the urea not remain inside.

The pump 56 allows the urea to circulate in the supply module 50.

4 is a schematic diagram of a selective catalytic reduction system using urea, in which FIG. 4A is a schematic diagram in a normal injection mode, and FIG. 4B is a schematic diagram in an after-run mode.

4A shows that the reversing valve 55 does not operate so that the urea flows through the urea tank 60 and the supply module 50 to the urea injection nozzle 20. 4B shows that the reversing valve 55 operates during the after-run operation so that the urea is recovered to the urea tank 60.

The reversing valve 55 is a valve capable of circulating the urea in the forward direction during normal operation and in the reverse direction during the after-run operation.

Figure 5 is a graph showing the pressure change in the urea line 40 during the after run operation, the after run function is a step of reducing the pressure of the urea line 40 from about 9 bar to about 0.25 bar, reversing A step of recovering urea to the tank side using the valve 55 includes a vacuum step of generating a negative pressure in the urea line 40 and a pressure balancing step of releasing the negative pressure generated in the vacuum step.

However, as illustrated in FIG. 5, urea may freeze in winter to break main components. This is because the pressure of the urea line 40 is not recovered even in the pressure equilibrium stage and the negative pressure is maintained almost intact. In severe cases, the urea remaining in the urea line 40 freezes, so that the SCR system may not operate.

The reason why the inlet of the urea injection nozzle 20 is clogged during the after-run operation is that the negative pressure is not sufficiently released in the pressure balancing step. The negative pressure at this time may be 300 mbar or less.

FIG. 5 is a graph illustrating the cause of clogging the inlet of the urea injection nozzle 20 during the after-run operation. As shown in FIG. 5, the pressure in the urea line 40 lower than the normal pressure in the vacuum stage is a pressure equilibrium stage. It should be similar to the atmospheric pressure, it can be seen that the plugged urea injection nozzle 20, the "nozzle clogging" phenomenon occurs that the pressure is not balanced.

The blockage phenomenon at the inlet of the urea injection nozzle 20 as described above may cause breakage and malfunction of components, particularly when the outside air temperature is low, such as in winter.

According to the embodiment of the present invention, in order to prevent such a phenomenon, the layout of the urea line 40 for supplying urea to the urea injection nozzle 20 is changed.

That is, according to the exemplary embodiment of the present invention, the urea tank 60 storing the urea 62 and the urea 62 in the urea tank 60 may be recovered to recover the supplied urea 62 during the after-run operation. Optionally comprising a supply module 50 including a reversing valve 55 and a urea injection nozzle 20 for injecting urea supplied from the supply module 50 to the front end of the SCR catalyst 12. In the catalytic reduction system, the layout of the urea line 40 for supplying the urea 62 from the supply module 50 to the urea injection nozzle 20 is changed so that the urea line 40 is shown in FIG. 1. A portion is formed below the lowest horizontal line H of the urea inside the urea spray nozzle 20. In FIG. 1, I means an injection line through which urea is injected. The angle formed by the lowest horizontal line H and the injection line I is called the mounting angle α. When the mounting angle is 0 ° or more, urea is injected into the exhaust pipe 10.

That is, the urea line 40 has a downward portion 42 extending downward to facilitate the recovery of urea at a portion connected to the urea injection nozzle 20, and is horizontally connected to the downward portion 42. And a horizontal portion 44. During the after run operation, the downward portion 42 becomes an empty space, and urea may remain in the horizontal portion 44, but the residual urea does not contact with the urea injection nozzle 20, so that it is not crystallized. By doing so, not only the phenomenon in which the inlet is blocked by crystallization of urea remaining at the inlet of the urea injection nozzle 20 can be prevented, but also the contamination of the inlet of the urea injection nozzle 20 can be prevented.

In addition, according to another embodiment of the present invention there is provided a system for mounting the urea injection nozzle 20 to enable upward injection in front of the selective reduction catalyst.

This is shown in Figure 2, when the mounting angle (α) of the urea injection nozzle 20 is mounted so as to be 0 ° or less relative to the lowest horizontal line (H), the urea injection nozzle 20 without changing the layout separately Blockage at the entrance can be prevented.

Hereinafter, an embodiment of the present invention will be described in more detail with reference to FIGS. 1 to 3.

1 shows a urea injection nozzle 20 and a urea line 40 according to an embodiment of the present invention, wherein the mounting angle α of the urea injection nozzle 20 is 0 ° based on the lowest horizontal line H. The above case is shown.

The urea line 40 includes a downward portion 42 and a horizontal portion 44 so that the urea can be easily recovered during the after-run operation. That is, during the after-run operation, the inlet tip of the urea injection nozzle 20 should be open so that the urea is recovered to the urea tank 60 when the urea line 40 has a negative pressure, and the pressure equilibrium is easily achieved. The pressure in line 40 and atmospheric pressure are similar to prevent backflow of urea.

In addition to changing the layout of the urea line 40 as described above, if the mounting angle of the urea injection nozzle 20 is set to be 0 ° or less relative to the lowest horizontal line, the urea can be sprayed upward without changing the layout of the urea line 40. When the urea stops spraying, the urea moves downward and does not block the inlet of the urea spray nozzle 20 during the after-run operation so that the urea remaining in the urea spray nozzle 20 can be easily recovered.

By changing the layout of the urea line 40 or the mounting angle α of the urea injection nozzle 20 as described above, it is possible to prevent backflow of urea during the after-run operation.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, And all changes to the scope that are deemed to be valid.

10: exhaust pipe 12: SCR catalyst
15: temperature sensor 20: urea spray nozzle
25: Injection Control (DCU) 30: Urea Line
40: urea line 42: downward portion
44: horizontal section 50: supply module
52: filter 55: reversing valve
56: pump 60: urea tank
62: urea

Claims (3)

In the selective catalytic reduction system comprising a urea tank, a supply module for supplying urea in the urea tank, and a urea injection nozzle for injecting urea supplied from the supply module to the front of the selective reduction catalyst,
And a portion of the urea line for supplying the urea from the supply module to the urea injection nozzle comprises a horizontal portion formed below the lowest horizontal line of the urea inside the urea injection nozzle. The method of claim 1,
The urea line is a selective catalytic reduction system, characterized in that the downward portion is formed in a portion connected to the urea injection nozzle. In the selective catalytic reduction system comprising a urea tank, a supply module for supplying urea in the urea tank, and a urea injection nozzle for injecting urea supplied from the supply module to the front end of the selective catalytic reduction,
The urea injection nozzle is a selective catalytic reduction system, characterized in that mounted to the front end of the selective reduction catalyst to enable the injection of urea to the selective reduction catalyst.
KR1020110075165A 2011-07-28 2011-07-28 Selective catalytic reduction KR20130013487A (en)

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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20150074342A (en) * 2013-12-24 2015-07-02 현대자동차주식회사 Urea back current prevent device of SCR system for diesel engine
CN108150256A (en) * 2017-12-23 2018-06-12 无锡威孚力达催化净化器有限责任公司 Urea nozzle protective device
KR20180067120A (en) 2016-12-12 2018-06-20 현대자동차주식회사 Method for Increasing Urea Decomposing Resolution and Urea Dosing System thereof
WO2018137914A1 (en) * 2017-01-25 2018-08-02 Robert Bosch Gmbh Delivery module for a metering system for metering a reducing agent into the exhaust gas section of a motor vehicle, and metering system
JP2018127960A (en) * 2017-02-09 2018-08-16 ボッシュ株式会社 Abnormality diagnosis device and method for reductant injection device
CN109630242A (en) * 2017-10-09 2019-04-16 罗伯特·博世有限公司 Conveyor module for trandfer fluid

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20150074342A (en) * 2013-12-24 2015-07-02 현대자동차주식회사 Urea back current prevent device of SCR system for diesel engine
KR20180067120A (en) 2016-12-12 2018-06-20 현대자동차주식회사 Method for Increasing Urea Decomposing Resolution and Urea Dosing System thereof
WO2018137914A1 (en) * 2017-01-25 2018-08-02 Robert Bosch Gmbh Delivery module for a metering system for metering a reducing agent into the exhaust gas section of a motor vehicle, and metering system
KR20190104617A (en) * 2017-01-25 2019-09-10 로베르트 보쉬 게엠베하 Transfer module and metering system for metering system for metering reducing agent into the exhaust section of the vehicle
CN110234851A (en) * 2017-01-25 2019-09-13 罗伯特·博世有限公司 Conveyor module and dosing system for the dosing system being metered into reducing agent in automobile exhausting system
US20190383191A1 (en) * 2017-01-25 2019-12-19 Robert Bosch Gmbh Delivery module for a metering system for metering a reducing agent into the exhaust gas section of a motor vehicle, and metering system
US10914216B2 (en) 2017-01-25 2021-02-09 Robert Bosch Gmbh Delivery module for a metering system for metering a reducing agent into the exhaust gas section of a motor vehicle, and metering system
JP2018127960A (en) * 2017-02-09 2018-08-16 ボッシュ株式会社 Abnormality diagnosis device and method for reductant injection device
CN109630242A (en) * 2017-10-09 2019-04-16 罗伯特·博世有限公司 Conveyor module for trandfer fluid
CN109630242B (en) * 2017-10-09 2022-08-16 罗伯特·博世有限公司 Delivery module for delivering a fluid
CN108150256A (en) * 2017-12-23 2018-06-12 无锡威孚力达催化净化器有限责任公司 Urea nozzle protective device

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