CN109563754B - Device and method for removing urea-derived deposits from internal combustion engine - Google Patents
Device and method for removing urea-derived deposits from internal combustion engine Download PDFInfo
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- CN109563754B CN109563754B CN201780048161.XA CN201780048161A CN109563754B CN 109563754 B CN109563754 B CN 109563754B CN 201780048161 A CN201780048161 A CN 201780048161A CN 109563754 B CN109563754 B CN 109563754B
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- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 title claims abstract description 169
- 238000002485 combustion reaction Methods 0.000 title claims abstract description 56
- 238000000034 method Methods 0.000 title claims description 19
- 238000011144 upstream manufacturing Methods 0.000 claims abstract description 50
- WTHDKMILWLGDKL-UHFFFAOYSA-N urea;hydrate Chemical compound O.NC(N)=O WTHDKMILWLGDKL-UHFFFAOYSA-N 0.000 claims abstract description 42
- 238000010926 purge Methods 0.000 claims description 90
- 238000005259 measurement Methods 0.000 claims description 25
- 238000004140 cleaning Methods 0.000 claims description 4
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- 239000007789 gas Substances 0.000 description 91
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- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 22
- 238000002347 injection Methods 0.000 description 14
- 239000007924 injection Substances 0.000 description 14
- 238000000746 purification Methods 0.000 description 12
- 229910021529 ammonia Inorganic materials 0.000 description 11
- 230000003647 oxidation Effects 0.000 description 11
- 238000007254 oxidation reaction Methods 0.000 description 11
- 239000000446 fuel Substances 0.000 description 8
- 239000007864 aqueous solution Substances 0.000 description 7
- 238000009825 accumulation Methods 0.000 description 6
- 239000000243 solution Substances 0.000 description 6
- 238000001514 detection method Methods 0.000 description 4
- 229930195733 hydrocarbon Natural products 0.000 description 4
- 150000002430 hydrocarbons Chemical class 0.000 description 4
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- 239000000126 substance Substances 0.000 description 4
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 3
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 description 3
- 229910002091 carbon monoxide Inorganic materials 0.000 description 3
- 238000002474 experimental method Methods 0.000 description 3
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 3
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- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 1
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 1
- 229910021536 Zeolite Inorganic materials 0.000 description 1
- 239000010953 base metal Substances 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 238000010531 catalytic reduction reaction Methods 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- HNPSIPDUKPIQMN-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Al]O[Al]=O HNPSIPDUKPIQMN-UHFFFAOYSA-N 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000007062 hydrolysis Effects 0.000 description 1
- 238000006460 hydrolysis reaction Methods 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
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- 239000011733 molybdenum Substances 0.000 description 1
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- 238000000859 sublimation Methods 0.000 description 1
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- 150000003672 ureas Chemical class 0.000 description 1
- LEONUFNNVUYDNQ-UHFFFAOYSA-N vanadium atom Chemical compound [V] LEONUFNNVUYDNQ-UHFFFAOYSA-N 0.000 description 1
- 238000009834 vaporization Methods 0.000 description 1
- 230000008016 vaporization Effects 0.000 description 1
- 239000010457 zeolite Substances 0.000 description 1
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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
-
- 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
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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)
- Biomedical Technology (AREA)
- Analytical Chemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
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Abstract
A device (110) for removing urea-derived deposits from an internal combustion engine is provided with a removal control unit (101), wherein the removal control unit (101) executes removal control of urea-derived deposits derived from urea water supplied from a urea SCR device (60) arranged in an exhaust passage (30) of the internal combustion engine (10), and the removal control unit executes the removal control each time a preset first time elapses, measures a low-temperature operating time, which is an operating time of the internal combustion engine at which the temperature of exhaust gas on the upstream side of the urea SCR device is equal to or lower than a predetermined temperature, and executes the removal control regardless of whether the first time elapses even when the measured low-temperature operating time exceeds a preset second time.
Description
Technical Field
The present invention relates to a device and a method for removing urea-derived deposits from an internal combustion engine.
Background
Conventionally, as a device for removing NOx discharged from an internal combustion engine, there is known a urea SCR device which supplies urea water to exhaust gas and reduces and removes NOx in the exhaust gas using ammonia generated from the supplied urea water as a reducing agent. When this urea SCR device is applied to an internal combustion engine, a part of the urea water supplied from the urea SCR device into the exhaust gas may adhere to, for example, an exhaust passage to generate urea-derived deposits derived from the urea water. As control for removing the urea source deposit (referred to as purge control), for example, control is known in which the urea source deposit is removed by sublimation or vaporization of the urea source deposit by raising the temperature of the exhaust gas upstream of the urea SCR device (see, for example, patent documents 1 and 2).
[ Prior art documents ]
[ patent document ]
Patent document 1: japanese patent application laid-open No. 2010-101237
Patent document 2: japanese laid-open patent publication No. 2009 and 257190
Disclosure of Invention
[ problems to be solved by the invention ]
However, purge control for removing urea-derived deposits may be executed every time a predetermined time elapses (hereinafter, this purge control is referred to as "time-based purge control"). However, the lower the exhaust gas temperature is, and the longer the period of time at the low temperature is, the greater the amount of urea-derived deposits tends to deposit. Therefore, when only the time-based purge control is executed as the purge control, if the operation time (low-temperature operation time) of the internal combustion engine at which the exhaust gas temperature on the upstream side of the urea SCR device becomes low exceeds a predetermined time, a large amount of urea-derived deposits that cannot be completely removed by the time-based purge control may be deposited.
The present invention has been made in view of the above circumstances, and an object thereof is to provide a device and a method for removing urea-derived deposits in an internal combustion engine, which can suppress accumulation of a large amount of urea-derived deposits that cannot be completely removed by time-based purge control.
[ means for solving the problems ]
In order to achieve the above object, a device for removing urea-derived deposits from an internal combustion engine according to the present invention includes a purge control unit configured to execute purge control for removing urea-derived deposits derived from urea water supplied from a urea SCR device disposed in an exhaust passage of the internal combustion engine, wherein the purge control unit executes the purge control every time a preset first time elapses, measures a low-temperature operating time that is an operating time of the internal combustion engine in which a temperature of exhaust gas on an upstream side of the urea SCR device is equal to or lower than a predetermined temperature, and executes the purge control regardless of whether the first time elapses or not when the measured low-temperature operating time exceeds a preset second time.
In order to achieve the above object, a method for removing urea-derived deposits in an internal combustion engine according to the present disclosure performs purge control for removing urea-derived deposits from urea water supplied from a urea SCR device disposed in an exhaust passage of the internal combustion engine every time a preset first time elapses, measures a low-temperature operating time that is an operating time of the internal combustion engine in which a temperature of exhaust gas on an upstream side of the urea SCR device is equal to or lower than a predetermined temperature, and performs the purge control regardless of whether the first time elapses or not when the measured low-temperature operating time exceeds a preset second time.
Effects of the invention
According to the present disclosure, in the case where the purge control is executed every time the first time elapses, and even if the low-temperature operating time exceeds the second time, since the purge control is executed regardless of whether the first time elapses, the urea source deposit can be effectively removed. This can prevent the deposit from being incompletely removed and a large amount of urea-derived deposit from being deposited in the purge control (per-time purge control) executed each time the first time elapses.
Drawings
Fig. 1 is a block diagram schematically showing the overall configuration of an internal combustion engine system according to an embodiment.
Fig. 2 is an example of a flowchart showing the low-temperature purge control and a series of control processes related thereto.
Detailed Description
(embodiment mode 1)
Hereinafter, a urea-derived deposit removal device 110 for an internal combustion engine and a urea-derived deposit removal method for an internal combustion engine according to embodiment 1 of the present invention will be described with reference to the drawings. Fig. 1 is a configuration diagram schematically showing the overall configuration of an internal combustion engine system 1 to which a removal device 110 according to the present embodiment is applied. The internal combustion engine system 1 includes an internal combustion engine 10, an intake passage 20, an exhaust passage 30, an exhaust gas purification device 50, a urea SCR (Selective Catalytic Reduction) device 60, various sensors (a temperature sensor 40 is illustrated in fig. 1), and a control device 100.
The removal device 110 according to the present embodiment is realized by the function of the control device 100. The removal method according to the present embodiment is realized by the control processing of the control device 100.
In the present embodiment, a diesel engine is used as an example of the internal combustion engine 10. In fig. 1, the number of cylinders 13 of the internal combustion engine 10 is 4, but the number of cylinders 13 is not limited to this. The intake passage 20 is a passage through which intake air taken into the internal combustion engine 10 passes, and a downstream end portion thereof is branched and connected to an intake port of each cylinder 13. The exhaust passage 30 is a passage through which exhaust gas discharged from the internal combustion engine 10 passes, and an upstream end portion thereof branches and is connected to an exhaust port of each cylinder 13.
The exhaust gas purification device 50 is disposed in the exhaust passage 30 on the upstream side of the urea SCR device 60. The exhaust gas purification device 50 includes an oxidation catalyst 51, and a filter 52 capable of collecting PM such as soot contained in the exhaust gas. The filter 52 is disposed downstream of the oxidation catalyst 51. In the present embodiment, a diesel particulate filter, specifically, a wall-flow particulate filter is used as an example of the filter 52.
The oxidation catalyst 51 converts harmful substances such as carbon monoxide (CO) and Hydrocarbons (HC) contained in the exhaust gas into water (H) by the catalytic action of the oxidation catalyst 512O) or carbon dioxide (CO)2) Such a harmful substance, thereby purifying the harmful substance in the exhaust gas. If it is provided with such a function,the specific configuration of the oxidation catalyst 51 is not particularly limited, and the oxidation catalyst 51 of the present embodiment has a configuration in which a noble metal catalyst such as platinum (Pt) or palladium (Pd) is supported on a carrier through which exhaust gas can pass, as an example.
In the present embodiment, the exhaust gas purification apparatus 50 is not essential to the internal combustion engine system 1, and for example, the internal combustion engine system 1 may be configured without the exhaust gas purification apparatus 50. However, when the internal combustion engine system 1 includes the exhaust gas purification device 50, it is preferable in that the exhaust gas can be efficiently purified as compared with a case where the exhaust gas purification device 50 is not provided.
The urea SCR device 60 is disposed in the exhaust passage 30 on the downstream side of the exhaust gas purification device 50. The urea SCR device 60 is a NOx purification device having the following functions: supplying urea water to exhaust gas, and supplying ammonia (NH) generated from the urea water supplied to the exhaust gas3) As a reducing agent to reduce NOx in the exhaust gas. The specific configuration of the urea SCR device 60 is not particularly limited if it has such a function, and in the present embodiment, the urea water supply unit 61, the urea SCR catalyst 62, and the ammonia slip catalyst 63 are provided as an example.
The urea aqueous solution supply unit 61 is disposed in the exhaust passage 30 on the upstream side of the urea SCR catalyst 62 and on the downstream side of the filter 52. As an example of the urea solution supply unit 61, in the present embodiment, a urea solution injection valve that injects urea solution into exhaust gas in response to an instruction from the control device 100 is used. The control device 100 controls the timing of supplying the urea aqueous solution and the amount of the urea aqueous solution to the urea aqueous solution supply unit 61.
The urea SCR catalyst 62 is a catalyst that selectively reduces NOx in exhaust gas using ammonia generated by hydrolysis of urea. Specific types of the urea SCR catalyst 62 are not particularly limited, and for example, known NOx selective reduction catalysts such as base metal oxides such as vanadium (V) and molybdenum (Mo), and noble metals such as zeolite can be used. The ammonia slip catalyst 63 is disposed downstream of the urea SCR catalyst 62. The ammonia slip catalyst 63 is an oxidation catalyst for oxidizing ammonia that has passed through the urea SCR catalyst 62.
When the urea aqueous solution is supplied from the urea aqueous solution supply portion 61 to the exhaust gas, the urea in the urea aqueous solution is hydrolyzed, and as a result, ammonia is generated. This ammonia reduces NOx under the catalytic action of urea SCR catalyst 62. As a result, nitrogen (N2) and water are generated. In this way, the urea SCR device 60 achieves reduction of NOx in the exhaust gas. Further, according to the present embodiment, since the ammonia slip catalyst 63 is provided, the discharge of ammonia to the outside of the internal combustion engine system 1 is effectively suppressed.
The temperature sensor 40 detects the temperature of the exhaust gas on the upstream side of the urea SCR device 60, and transmits the detection result to the control device 100. The specific location of the temperature sensor 40 in the exhaust passage 30 is not particularly limited as long as it is a portion on the upstream side of the urea SCR device 60, but in the present embodiment, the temperature sensor is disposed on a portion on the upstream side of the urea SCR device 60 and on the downstream side of the filter 52 of the exhaust gas purification device 50, and the exhaust gas temperature of the portion is detected.
The control device 100 controls the fuel injection amount, the fuel injection timing, and the like of the internal combustion engine 10, and also controls the urea water supply portion 61 of the urea SCR device 60. Such a control device 100 includes a microcomputer having a CPU101 for executing various controls, a storage unit 102 for storing various information, programs, and the like necessary for the operation of the CPU101, and the like. In addition, a storage device such as a ROM or a RAM is used as the storage unit 102.
The control device 100 according to the present embodiment also functions as a device 110 for removing urea-derived deposits from the internal combustion engine 10. The CPU101 of the control device 100 functions as a purge control unit that executes purge control for removing urea-derived deposits from the urea water supplied from the urea SCR device 60.
The urea-derived deposit may be, for example, a white solid deposit crystallized from the urea solution supplied from the urea solution supply unit 61. The urea-derived deposit is particularly likely to deposit in the exhaust passage 30 between the urea water supply unit 61 and the urea SCR catalyst 62. The urea water supplied from the urea water supply unit 61 to the exhaust gas is likely to accumulate when the temperature of the exhaust gas is particularly 150 to 300 ℃.
The specific content of the purge control is not particularly limited as long as it is a control capable of removing the urea source deposit, and in the present embodiment, as an example, a control is used in which the temperature of the exhaust gas on the upstream side of the urea SCR device 60 is increased to a temperature equal to or higher than the temperature at which the urea source deposit sublimates or vaporizes (for example, 320 ℃. By raising the temperature of the exhaust gas in this manner, the urea source deposit can be sublimated or vaporized and removed from the exhaust passage 30.
Specific examples of the control for increasing the temperature of the exhaust gas are not particularly limited, and for example, a remote injection control, a fuel injection control (referred to as "exhaust pipe injection control") to the exhaust passage 30 on the upstream side of the oxidation catalyst 51 of the exhaust purification apparatus 50, or a combination thereof may be used. In the remote post-injection control, fuel is injected into the cylinder 13 at a timing after the main injection. The hydrocarbons in the fuel injected by the remote post-injection control are oxidized in the oxidation catalyst 51, and the temperature of the exhaust gas on the upstream side of the urea SCR device 60 can be increased by the reaction heat at that time. In the exhaust pipe injection control, fuel is injected into the exhaust gas from an exhaust pipe injector disposed in the exhaust passage 30 upstream of the oxidation catalyst 51 in the exhaust purification apparatus 50. Hydrocarbons in the fuel injected from the exhaust pipe injector are oxidized in the oxidation catalyst 51, and the temperature of the exhaust gas on the upstream side of the urea SCR device 60 can be increased by the reaction heat at that time. In the present embodiment, as an example of the purge control, the remote injection control is executed.
The purge control unit (specifically, the CPU101) according to the present embodiment performs the above-described purge control (this purge control is referred to as "time-based purge control") each time a preset first time elapses. Specifically, the storage unit 102 of the control device 100 stores a first time (that is, a preset time) in advance, and the purge control unit executes purge control every time the first time elapses, thereby increasing the exhaust gas temperature and removing urea-derived deposits. The specific value of the first time is not particularly limited, and in the present embodiment, 30 hours (hr) is used as an example.
The purge control unit of the present embodiment measures a low-temperature operating time of the internal combustion engine 10 in which the temperature of the exhaust gas on the upstream side of the urea SCR device 60 is equal to or lower than a predetermined temperature, and executes purge control (this purge control is referred to as "low-temperature purge control") regardless of whether or not the first time has elapsed even when the measured low-temperature operating time exceeds a preset second time. The details of the low-temperature purge control will be described below with reference to fig. 2.
Fig. 2 is an example of a flowchart showing the low-temperature purge control and a series of control processes associated with the low-temperature purge control. The purge control portion starts execution of the flowchart of fig. 2 together with start of the internal combustion engine system 1. First, in step S10, the purge control unit determines whether or not a condition for starting measurement of the low temperature operating time (referred to as "measurement start condition") is satisfied.
In the present embodiment, as the measurement start condition, a condition under which urea-derived deposits are likely to be deposited (in other words, a condition under which a large amount of urea-derived deposits are likely to be deposited) is used. Here, the urea-derived deposit is accumulated in the exhaust passage 30, and the urea solution is supplied to the exhaust gas by the urea SCR device 60. Further, the lower the temperature of the exhaust gas on the upstream side than the urea SCR device 60, the smaller the flow rate of the exhaust gas on the upstream side of the urea SCR device 60, and the larger the supply amount of the urea water of the urea SCR device 60, the more likely the urea-derived deposits are deposited (that is, the greater the amount of deposits).
Therefore, in the present embodiment, as the measurement start condition, the condition that the state of the urea water supply unit 61 of the urea SCR device 60 supplying urea water (i.e., the state during the urea water supply) is used, the temperature of the exhaust gas on the upstream side of the urea SCR device 60 is equal to or lower than the predetermined temperature, the flow rate of the exhaust gas on the upstream side of the urea SCR device 60 is equal to or lower than the predetermined flow rate, and the amount of the urea water supplied by the urea water supply unit 61 of the urea SCR device 60 is equal to or larger than the predetermined supply amount is used.
Specific values of the predetermined temperature, the predetermined flow rate, and the predetermined supply amount are not particularly limited, and may be obtained in advance by, for example, experiments, simulations, or the like, and stored in advance in the storage unit 102 of the control device 100 (that is, may be set in advance). In the present embodiment, as an example of the predetermined temperature (the predetermined temperature of the exhaust gas), the same value as the predetermined temperature (a value selected from 150 to 300 ℃) of the exhaust gas temperature used in step S20 described later is used.
The purge control unit obtains the temperature of the exhaust gas based on the detection result of the temperature sensor 40. The purge control unit is obtained by estimating the flow rate of the exhaust gas based on the fuel supply amount and the intake air flow rate of the internal combustion engine 10, for example. In addition, when the internal combustion engine system 1 includes an exhaust gas flow rate sensor that detects a flow rate of the exhaust gas, the purge control unit may use a value detected by the exhaust gas flow rate sensor as the flow rate of the exhaust gas.
Step S10 is repeatedly executed until the determination is yes. If yes is determined in step S10, the purge control unit executes step S20. In step S20, the purge control unit starts measuring the low-temperature operation time (i.e., the operation time of the internal combustion engine 10 in which the temperature of the exhaust gas on the upstream side of the urea SCR device 60 is equal to or lower than a predetermined temperature). As a specific value of the predetermined temperature, a temperature at which deposits of urea-derived substances are likely to be deposited can be used. As a numerical example of the predetermined temperature, a value selected from a temperature range of 150 to 300 ℃ (150 ℃ to 300 ℃). Therefore, in the present embodiment, 250 ℃ is used as an example of the predetermined temperature. The predetermined temperature is stored in advance in the storage unit 102 of the control device 100.
That is, the purge control unit of the present embodiment acquires the temperature of the exhaust gas by acquiring the detection result of the temperature sensor 40 in step S20, and measures the operation time (low temperature operation time) of the internal combustion engine 10 at which the acquired temperature of the exhaust gas becomes a predetermined temperature or lower (250 ℃. The purge control unit stores the measured low-temperature operating time in the storage unit 102 of the control device 100.
After step S20, the purge control section executes step S30. In step S30, the purge control unit determines whether or not the low temperature operation time measured in step S20 exceeds a second time.
The specific value of the second time is not particularly limited, and for example, a time in which urea-derived deposits (i.e., a large amount of urea-derived deposits) are accumulated in an amount that cannot be completely removed only by the time purge control when the low-temperature operation time exceeds the specific value can be used. The second time is obtained in advance by, for example, experiments, simulations, or the like, and is stored in advance in the storage unit 102 of the control device 100. In the present embodiment, as an example of the second time, 10 hours (hr) are used.
If the determination in step S30 is "no," the purge control unit executes step S20 again. On the other hand, if it is determined as yes in step S30 (i.e., if the low temperature operation time exceeds the second time), the purge control unit executes step S40. In step S40, the purge control unit executes low-temperature purge control. Specifically, the purge control unit performs control to increase the temperature of the exhaust gas upstream of the urea SCR device 60 to a temperature equal to or higher than the temperature at which the urea source deposit sublimates or vaporizes. As a specific example of the control for raising the temperature of the exhaust gas, for example, as described above, the remote post injection control, the exhaust pipe injection control, or a combination thereof can be used. In the present embodiment, as an example of the low temperature purge control, the remote injection control is executed.
By executing the low-temperature purge control in step S40, the exhaust gas temperature rises, and the urea-derived deposits are sublimated or vaporized and removed. After this step S40, the clear control section executes a reset process in step S50. In this reset process, the purge control unit resets the low temperature operation time that has been measured. The purge control unit resets the elapsed time that has been measured to execute the time-based purge control, and restarts the measurement of the first time.
That is, when the low-temperature purge control is executed, the purge control unit according to the present embodiment resets the low-temperature operating time that has been measured and stored in the storage unit 102, and also resets the elapsed time that has been measured and stored in the storage unit 102 in order to execute the time-based purge control, and restarts the measurement of the first time. Thus, the next time purge control is executed when the first time has elapsed since the execution of the low temperature purge control. After step S50, the purge control unit starts execution of the flowchart (return).
Here, if the time-based purge control is executed only without executing the low-temperature purge control, a large amount of urea-derived deposits that cannot be removed by the time-based purge control may be deposited when the low-temperature operation time in which the temperature of the exhaust gas on the upstream side of the urea SCR device 60 is equal to or lower than the predetermined temperature exceeds the second time. In contrast, according to the present embodiment, even when the time-based purge control is executed every time the first time elapses and the low-temperature operating time exceeds the second time, the low-temperature purge control (step S40) is executed regardless of whether the first time elapses, and therefore, urea-derived deposits can be effectively removed. This can suppress the accumulation of a large amount of urea-derived deposits that cannot be completely removed by the time-based purge control.
In the present embodiment, the measurement of the low temperature operating time in step S20 is started only when the measurement start condition in step S10 in fig. 2 is satisfied, but the configuration of the present embodiment is not limited to this. For example, the purge control unit may be configured not to perform step S10. That is, in this case, the purge control unit measures the low temperature operation time regardless of whether or not the measurement start condition is satisfied. In this case, by executing the low-temperature purge control, it is also possible to suppress the accumulation of a large amount of urea-derived deposits.
However, as in the present embodiment, when the measurement of the low-temperature operating time in step S20 is started only when the measurement start condition in step S10 is satisfied, the measurement of the low-temperature operating time can be started when urea-derived deposits are likely to deposit, as compared with the case where the measurement start condition is not satisfied, and therefore, the deposition of a large amount of urea-derived deposits can be effectively suppressed.
(embodiment mode 2)
Next, embodiment 2 of the present invention will be explained. The removal device 110 and the removal method according to the present embodiment are different from the removal device 110 and the removal method according to embodiment 1 described above in that the measurement start condition according to step S10 in fig. 2 further includes a condition that the temperature of the pipe wall portion of the exhaust passage 30 on the upstream side of the urea SCR device 60 is equal to or lower than a predetermined temperature.
That is, the measurement start conditions of the present embodiment are: the condition that the urea water supply portion 61 of the urea SCR device 60 supplies urea water is that the temperature of the exhaust gas on the upstream side of the urea SCR device 60 is equal to or lower than a predetermined temperature, the flow rate of the exhaust gas on the upstream side of the urea SCR device 60 is equal to or lower than a predetermined flow rate, the urea water supply amount of the urea water supply portion 61 of the urea SCR device 60 is equal to or higher than a predetermined supply amount, and the temperature of the pipe wall portion of the exhaust passage 30 on the upstream side of the urea SCR device 60 is equal to or lower than a predetermined temperature.
As the temperature of the pipe wall portion of the exhaust passage 30, for example, the temperature of the pipe wall portion of the exhaust passage 30 on the upstream side of the urea SCR device 60 and on the downstream side of the filter 52 can be used. The temperature of the pipe wall portion can be obtained by obtaining a detection result of a temperature sensor that detects the temperature of the pipe wall portion. The predetermined temperature of the tube wall portion may be determined in advance by experiments, simulations, or the like to have an appropriate value, and stored in the storage unit 102 of the control device 100.
Here, as the temperature of the pipe wall portion of the exhaust passage 30 on the upstream side of the urea SCR device 60 is lower, urea-derived deposits tend to be deposited more easily. Therefore, according to the present embodiment, when the condition that urea-derived deposits are more likely to be deposited is satisfied, the measurement of the low-temperature operating time can be started in step S20. This can more effectively suppress the accumulation of a large amount of urea-derived deposits.
(embodiment mode 3)
Next, a third embodiment of the present disclosure will be explained. The removal device 110 and the removal method according to the present embodiment are different from those of embodiment 1 or embodiment 2 described above in that the measurement start conditions of step S10 further include conditions in which the temperature of the exhaust gas upstream of the urea SCR device 60, the flow rate of the exhaust gas upstream of the urea SCR device 60, and the amount of urea water supplied to the urea SCR device 60 are not in a transient state (a state that changes with the passage of time) but in a steady state (a state that does not change with the passage of time).
That is, the purge control unit according to the present embodiment starts the measurement of the low-temperature operating time in step S20 only when the conditions that the temperature of the exhaust gas on the upstream side of the urea SCR device 60 is in the steady state, the flow rate of the exhaust gas on the upstream side of the urea SCR device 60 is in the steady state, and the supply amount of the urea water of the urea SCR device 60 is in the steady state are satisfied in addition to the measurement start conditions according to embodiment 1 or embodiment 2 described above.
Here, in the case of the steady state, the urea-derived deposits tend to be deposited more easily than in the case where the temperature of the exhaust gas on the upstream side of the urea SCR device 60, the flow rate of the exhaust gas on the upstream side of the urea SCR device 60, and the supply amount of the urea water by the urea SCR device 60 are in the transient state. Therefore, according to the present embodiment, when the condition that urea-derived deposits are more likely to be deposited is satisfied in step S10, the measurement of the low-temperature operating time can be started in step S20. This can more effectively suppress the accumulation of a large amount of urea-derived deposits.
(embodiment mode 4)
Next, embodiment 4 of the present invention will be explained. The removing device 110 and the removing method according to the present embodiment are different from the above-described embodiments 1, 2, and 3 in that the purge control unit changes the second time (the second time according to step S30) based on the temperature of the exhaust gas on the upstream side of the urea SCR device 60, the flow rate of the exhaust gas on the upstream side of the urea SCR device 60, and the supply amount of the urea water of the urea SCR device 60.
Specifically, the purge control unit according to the present embodiment makes the second time shorter as the temperature of the exhaust gas on the upstream side of the urea SCR device 60 is lower, the second time shorter as the flow rate of the exhaust gas is smaller, and the second time shorter as the supply amount of the urea water of the urea SCR device 60 is larger.
More specifically, the storage unit 102 of the control device 100 according to the present embodiment stores a map or an arithmetic expression that defines the temperature of the exhaust gas, the flow rate of the exhaust gas, and the supply amount of the urea water in association with the second time in advance such that the second time is shorter as the temperature of the exhaust gas on the upstream side of the urea SCR device 60 is lower, and the second time is shorter as the flow rate of the exhaust gas on the upstream side of the urea SCR device 60 is lower, and the second time is shorter as the supply amount of the urea water of the urea SCR device 60 is larger.
The map or the arithmetic expression may be a map or an arithmetic expression defined as follows: the second time is shorter when the temperature of the exhaust gas on the upstream side of the urea SCR device 60 is equal to or lower than the reference exhaust gas temperature than when the temperature of the exhaust gas is higher than the reference exhaust gas temperature, is shorter when the flow rate of the exhaust gas on the upstream side of the urea SCR device 60 is equal to or lower than the reference exhaust gas flow rate than when the flow rate is higher than the reference exhaust gas flow rate, and is shorter when the supply amount of the urea water to the urea SCR device 60 is equal to or higher than the reference supply amount than when the supply amount is lower than the reference supply amount.
Then, in step S30, the purge control unit obtains the temperature of the exhaust gas on the upstream side of the urea SCR device 60, the flow rate of the exhaust gas, and the supply amount of the urea water to the urea SCR device 60, and calculates the second time based on the map or the arithmetic expression based on the obtained information, so that the second time is shortened as the temperature of the exhaust gas is lower, the second time is shortened as the flow rate of the exhaust gas is lower, and the second time is shortened as the supply amount of the urea water is larger.
Here, the lower the temperature of the exhaust gas on the upstream side of the urea SCR device 60, the lower the flow rate of the exhaust gas on the upstream side of the urea SCR device 60, and the greater the supply amount of the urea water, the more likely the urea-derived deposits will be deposited. Therefore, according to the present embodiment, the second time period in step S30 is shortened as the urea-derived deposits are more likely to be deposited, and the low-temperature purge control in step S40 can be easily started. This can more effectively suppress the accumulation of a large amount of urea-derived deposits.
The preferred embodiments of the apparatus and method for removing urea-derived deposits of an internal combustion engine according to the present invention have been described above, but the present invention is not limited to the specific embodiments and various modifications and changes can be made within the scope of the present invention.
The present application is based on Japanese patent application 2016 (Japanese application 2016-157757), filed on 10/08/2016, the contents of which are incorporated herein by reference.
Industrial applicability
The apparatus and method for removing urea-derived deposits of an internal combustion engine according to the present invention are useful in that a large amount of urea-derived deposits that cannot be completely removed by time-based purge control can be suppressed from accumulating.
Description of the reference symbols
1 internal combustion engine system, 10 internal combustion engine, 30 exhaust passage, 60 urea SCR device, 100 control device, 101CPU (cleaning control unit), 110 removal device of urea source deposit of internal combustion engine.
Claims (7)
1. A device for removing urea-derived deposits from an internal combustion engine,
the device is provided with a cleaning control unit for executing cleaning control for removing urea-derived deposits derived from urea water supplied from a urea SCR device disposed in an exhaust passage of an internal combustion engine,
the purge control section executes the purge control every time a first time set in advance elapses,
the device for removing urea-derived deposits of an internal combustion engine is characterized in that,
the purge control unit measures a low-temperature operating time, which is an operating time of the internal combustion engine at which a temperature of the exhaust gas upstream of the urea SCR device is equal to or lower than a predetermined temperature, and executes the purge control regardless of whether the first time has elapsed when the measured low-temperature operating time exceeds a second time set in advance.
2. The apparatus for removing urea-derived deposits from an internal combustion engine according to claim 1,
when the purge control is executed when the low temperature operation time exceeds the second time, the purge control unit resets the low temperature operation time that has been measured, and also resets an elapsed time that has been measured in order to execute the purge control every time the first time elapses, and starts measuring the first time again.
3. The apparatus for removing urea-derived deposits from an internal combustion engine according to claim 1 or 2,
the purge control unit starts the measurement of the low temperature operation time only when a measurement start condition is satisfied, the measurement start condition being: the urea SCR device is in a state of being supplied with urea water, the temperature of the exhaust gas on the upstream side of the urea SCR device is equal to or lower than a predetermined temperature, the flow rate of the exhaust gas is equal to or lower than a predetermined flow rate, and the supply amount of urea water of the urea SCR device is equal to or larger than a predetermined supply amount.
4. The apparatus for removing urea-derived deposits from an internal combustion engine according to claim 3,
the measurement start condition further includes: and a condition that a temperature of a pipe wall portion of the exhaust passage on an upstream side of the urea SCR device is equal to or lower than a predetermined temperature.
5. The apparatus for removing urea-derived deposits from an internal combustion engine according to claim 3,
the measurement start condition further includes a condition that the temperature of the exhaust gas, the flow rate of the exhaust gas, and the supply amount of the urea water are not in a transient state but in a steady state.
6. The apparatus for removing urea-derived deposits from an internal combustion engine according to claim 3,
the purge control unit may shorten the second time as the temperature of the exhaust gas is lower, the flow rate of the exhaust gas is smaller, and the supply amount of the urea water is larger.
7. A method for removing urea-derived deposits from an internal combustion engine,
executing a cleaning control of removing urea source deposit derived from urea water supplied from a urea SCR device disposed in an exhaust passage of an internal combustion engine every time a first time set in advance elapses,
the method for removing urea-derived deposits from an internal combustion engine is characterized in that,
the purge control is executed regardless of whether the first time has elapsed or not, even when a low-temperature operating time, which is an operating time of the internal combustion engine at which the temperature of the exhaust gas on the upstream side of the urea SCR device is equal to or lower than a predetermined temperature, is measured and the measured low-temperature operating time exceeds a second time set in advance.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2016157757A JP6705334B2 (en) | 2016-08-10 | 2016-08-10 | Apparatus and method for removing urea-derived deposits in an internal combustion engine |
| JP2016-157757 | 2016-08-10 | ||
| PCT/JP2017/027433 WO2018030178A1 (en) | 2016-08-10 | 2017-07-28 | Device and method for removing urea-derived deposits in internal combustion engine |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN109563754A CN109563754A (en) | 2019-04-02 |
| CN109563754B true CN109563754B (en) | 2021-02-19 |
Family
ID=61162459
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201780048161.XA Active CN109563754B (en) | 2016-08-10 | 2017-07-28 | Device and method for removing urea-derived deposits from internal combustion engine |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JP6705334B2 (en) |
| CN (1) | CN109563754B (en) |
| MY (1) | MY201140A (en) |
| PH (1) | PH12019500249A1 (en) |
| WO (1) | WO2018030178A1 (en) |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| ATE500879T1 (en) * | 2006-12-23 | 2011-03-15 | Alzchem Trostberg Gmbh | USE OF AQUEOUS GUANIDINIUM FORMIATE SOLUTIONS FOR THE SELECTIVE CATALYTIC REDUCTION OF NITROGEN OXIDES IN VEHICLE EXHAUST GASES |
| US8079211B2 (en) * | 2008-11-06 | 2011-12-20 | Ford Global Technologies, Llc | Bypass purge for protecting against formation of reductant deposits |
| JP2011220232A (en) * | 2010-04-09 | 2011-11-04 | Ud Trucks Corp | Exhaust emission control device for engine |
| JP2011247135A (en) * | 2010-05-25 | 2011-12-08 | Isuzu Motors Ltd | Scr system |
| SE536889C2 (en) * | 2012-03-22 | 2014-10-21 | Scania Cv Ab | Device and method for cleaning an SCR system |
| EP2927443A1 (en) * | 2014-04-02 | 2015-10-07 | Caterpillar Inc. | Apparatus and method for detecting urea deposit formation |
| JP2017040195A (en) * | 2015-08-19 | 2017-02-23 | 株式会社デンソー | Exhaust purification system control device |
-
2016
- 2016-08-10 JP JP2016157757A patent/JP6705334B2/en active Active
-
2017
- 2017-07-28 CN CN201780048161.XA patent/CN109563754B/en active Active
- 2017-07-28 WO PCT/JP2017/027433 patent/WO2018030178A1/en active Application Filing
- 2017-07-28 MY MYPI2019000667A patent/MY201140A/en unknown
-
2019
- 2019-02-04 PH PH12019500249A patent/PH12019500249A1/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| JP6705334B2 (en) | 2020-06-03 |
| WO2018030178A1 (en) | 2018-02-15 |
| JP2018025156A (en) | 2018-02-15 |
| PH12019500249A1 (en) | 2019-10-21 |
| MY201140A (en) | 2024-02-07 |
| CN109563754A (en) | 2019-04-02 |
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