WO2019039481A1 - 排気浄化システムの制御装置 - Google Patents

排気浄化システムの制御装置 Download PDF

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Publication number
WO2019039481A1
WO2019039481A1 PCT/JP2018/030876 JP2018030876W WO2019039481A1 WO 2019039481 A1 WO2019039481 A1 WO 2019039481A1 JP 2018030876 W JP2018030876 W JP 2018030876W WO 2019039481 A1 WO2019039481 A1 WO 2019039481A1
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WO
WIPO (PCT)
Prior art keywords
nox
amount
ozone
ozone supply
exhaust
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/JP2018/030876
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English (en)
French (fr)
Japanese (ja)
Inventor
佑輔 真島
樋口　和弘
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Denso Corp
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Denso Corp
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Filing date
Publication date
Application filed by Denso Corp filed Critical Denso Corp
Priority to DE112018004733.4T priority Critical patent/DE112018004733T5/de
Publication of WO2019039481A1 publication Critical patent/WO2019039481A1/ja
Priority to US16/783,251 priority patent/US20200173328A1/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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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
    • F01N3/206—Adding periodically or continuously substances to exhaust gases for promoting purification, e.g. catalytic material in liquid form, NOx reducing agents
    • F01N3/208—Control of selective catalytic reduction [SCR], e.g. by adjusting the dosing of reducing agent
    • 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
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B13/00—Oxygen; Ozone; Oxides or hydroxides in general
    • C01B13/10—Preparation of ozone
    • C01B13/11—Preparation of ozone by electric discharge
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES
    • F01N11/00—Monitoring or diagnostic devices for exhaust-gas treatment apparatus
    • 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
    • F01N3/0807—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by using absorbents or adsorbents
    • F01N3/0814—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by using absorbents or adsorbents combined with catalytic converters, e.g. NOx absorption/storage reduction catalysts
    • 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
    • F01N3/0807—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by using absorbents or adsorbents
    • F01N3/0828—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by using absorbents or adsorbents characterised by the absorbed or adsorbed substances
    • F01N3/0842—Nitrogen oxides
    • 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
    • F01N9/00—Electrical control of exhaust gas treating apparatus
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES
    • 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
    • F01N2240/38—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 ozone (O3) generator, e.g. for adding ozone after generation of ozone from air
    • 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
    • F01N2550/00—Monitoring or diagnosing the deterioration of exhaust systems
    • 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
    • F01N2560/00—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics
    • F01N2560/02—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics the means being an exhaust gas sensor
    • F01N2560/026—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics the means being an exhaust gas sensor for measuring or detecting NOx
    • 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
    • F01N2610/06—Adding substances to exhaust gases the substance being in the gaseous form
    • 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
    • F01N2900/00—Details of electrical control or of the monitoring of the exhaust gas treating apparatus
    • F01N2900/06—Parameters used for exhaust control or diagnosing
    • F01N2900/14—Parameters used for exhaust control or diagnosing said parameters being related to the exhaust gas
    • F01N2900/1402—Exhaust gas composition
    • 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

Definitions

  • the present disclosure relates to a control device of an exhaust purification system provided with a NOx storage reduction type catalyst that purifies NOx (nitrogen oxide).
  • the present disclosure has been made in view of the above problems, and a main object thereof is to provide a control device of an exhaust gas purification system capable of performing ozone supply properly and thus achieving proper NOx purification. .
  • the control device of the exhaust gas purification system in this means is An NOx storage reduction type catalyst provided in an exhaust passage of an internal combustion engine for purifying NOx in exhaust gas, an ozone supply device for supplying ozone to the upstream side of the catalyst in the exhaust passage, and provided downstream of the catalyst Applied to an exhaust purification system comprising a NOx sensor for detecting the amount of NOx in the exhaust, A NOx amount acquisition unit that acquires the detected NOx amount detected by the NOx sensor when the internal combustion engine is in operation and ozone is being supplied by the ozone supply device; A control unit that performs at least one of ozone supply amount control by the ozone supply device and abnormality diagnosis of the ozone supply device based on the detected NOx amount acquired by the NOx amount acquisition unit; Equipped with
  • the ozone supply device supplies ozone to the upstream side of the NOx storage reduction catalyst in the exhaust gas passage of the internal combustion engine, whereby NO in the exhaust gas is oxidized to NO2. This makes it possible to enhance the NOx storage capacity of the NOx storage reduction catalyst. In such a case, if the amount of ozone supplied by the ozone supply device is unintentionally reduced, the NOx storage capacity of the NOx storage reduction catalyst is reduced, and as a result, there is a concern that the NOx purification performance will be reduced.
  • the detected NOx amount detected by the NOx sensor is obtained in the state where the internal combustion engine is in operation and ozone is supplied by the ozone supply device, and ozone is obtained based on the detected NOx amount.
  • At least one of the ozone supply amount control by the supply device and the abnormality diagnosis of the ozone supply device is performed.
  • FIG. 1 is a block diagram showing an engine exhaust purification system
  • FIG. 2 is a diagram showing the relationship between the amount of ozone to NO in exhaust gas and the storage efficiency
  • FIG. 3 is a flowchart showing the control procedure of ozone supply
  • FIG. 4 is a diagram showing the relationship between various parameters and estimated NOx amount (NOx_est)
  • FIG. 5 is a view showing the relationship between the difference ⁇ Y and the correction amount.
  • an engine 10 is a multi-cylinder diesel engine fueled with light oil, and an intake pipe 11 and an exhaust pipe 12 are connected to each cylinder.
  • the engine 10 is provided with a supercharging device 13.
  • the supercharging device 13 includes an intake compressor 14 disposed in the intake pipe 11, an exhaust turbine 15 disposed in the exhaust pipe 12, and a rotary shaft 16 connecting the intake compressor 14 and the exhaust turbine 15.
  • An intercooler as a heat exchanger may be disposed downstream of the intake compressor 14 in the intake pipe 11.
  • An air amount sensor 18 for detecting an amount of air passing through the intake pipe 11 is provided on the upstream side of the intake compressor 14 in the intake pipe 11. Further, on the output shaft of the engine 10, a rotational speed sensor 19 for detecting the engine rotational speed is provided.
  • the exhaust pipe 12 is provided with a NOx storage reduction catalyst (hereinafter referred to as a NOx catalyst 21) as a NOx purification device for purifying NOx in the exhaust gas flowing in the exhaust passage in the exhaust pipe 12.
  • a NOx catalyst 21 occludes NOx contained in the exhaust during lean combustion, and reduces and eliminates the stored NOx using a reducing component such as HC or CO contained in the exhaust during rich combustion. It is a thing.
  • the NOx catalyst 21 has, for example, a structure in which silver as a reduction catalyst is supported on alumina coated on the support surface.
  • a NOx sensor 22 for detecting the amount of NOx in the exhaust discharged from the engine 10 and an exhaust temperature sensor 23 for detecting the exhaust temperature are provided on the upstream side of the NOx catalyst 21 in the exhaust pipe 12.
  • these sensors 22 and 23 are provided in the upstream rather than the below-mentioned supply pipe 31.
  • a NOx sensor 24 for detecting the amount of NOx on the downstream side of the catalyst is provided on the downstream side of the NOx catalyst 21.
  • the NOx catalyst 21 is provided with a catalyst temperature sensor 25 for detecting the catalyst temperature.
  • the NOx sensors 22 and 24 are, for example, limiting current type gas sensors that constitute a solid electrolyte.
  • the NOx sensor 22 on the upstream side of the catalyst is also referred to as the NOx sensor 22 on the upstream side, and the NOx sensor 24 on the downstream side of the catalyst as the downstream NOx sensor 24.
  • the catalyst temperature sensor 25 may be provided downstream of the NOx catalyst 21.
  • ozone (O 3) is supplied to the upstream side of the NOx catalyst 21 in the exhaust pipe 12, and NO in the exhaust gas is oxidized to NO 2 by the ozone, thereby occluding NOx in the NOx catalyst 21.
  • a supply pipe 31 is connected to the exhaust pipe 12 on the upstream side of the NOx catalyst 21.
  • the supply pipe 31 is provided with an air pump 32, an ozone generator 33, and an on-off valve 34 in this order from the upstream side.
  • the air pump 32 is, for example, an electric pump, which pressurizes the air drawn from the outside and blows it to the ozone generator 33. Since the configuration of the ozone generator 33 is well known, detailed description by illustration is omitted, but simply stated, in the ozone generator 33, a plurality of electrodes are arranged in a vessel forming a flow passage. The ozone is generated by applying a high voltage between the plurality of electrodes.
  • the on-off valve 34 is provided for the purpose of suppressing the backflow of the exhaust gas from the exhaust pipe 12, and is opened when ozone is supplied to the exhaust pipe 12, and closed when the ozone supply is stopped.
  • the air pump 32 and the ozone generator 33 correspond to an ozone supply device.
  • the ECU 40 is a known electronic control unit mainly composed of a microcomputer (hereinafter referred to as a microcomputer) consisting of a CPU, a ROM, a RAM, etc., and executes the various control programs stored in the ROM as described above. Based on detection signals from various sensors, various controls on exhaust gas purification are performed.
  • the ECU 40 performs ozone supply amount control to control the ozone supply amount by the ozone supply device to a desired amount.
  • the ECU 40 controls the states of the air pump 32, the ozone generator 33, and the on-off valve 34 in order to supply, for example, a predetermined amount of ozone to the exhaust pipe 12. Under the operating condition of the engine 10, for example, the ECU 40 performs ozone supply to the exhaust pipe 12 according to the demand, assuming that the demand for ozone supply occurs during lean combustion.
  • the storage efficiency differs between NO and NO2 out of the NOx contained in the exhaust gas, and the storage efficiency of NO becomes extremely low at a relatively low temperature state. Therefore, ozone is supplied to the exhaust pipe 12 for the purpose of oxidizing NO to NO2 by ozone under low temperature conditions, but if ozone is insufficient due to the performance decrease of the ozone supply device, it is It is conceivable that the oxidation of NO to NO2 is insufficient. In such a case, the ratio of NO in NOx increases, so there is a concern that the NOx storage efficiency of the NOx catalyst 21 may be reduced.
  • FIG. 2 is a view showing the relationship between the amount of ozone and NO in the exhaust gas and the storage efficiency. According to FIG. 2, it can be seen that the storage efficiency of the NOx catalyst 21 decreases as the amount of ozone to NO in the exhaust gas decreases.
  • the NOx catalyst 21 can not exhibit desired NOx purification performance. Therefore, in the present embodiment, when the engine 10 is in operation and ozone is supplied by the ozone supply device, the detected NOx amount (NOx_sens) detected by the downstream side NOx sensor 24 is acquired, and the detected NOx is detected. Based on the amount (NOx_sens), ozone supply amount control by the ozone supply device and abnormality diagnosis of the ozone supply device are performed.
  • the ECU 40 calculates the NOx amount discharged downstream of the NOx catalyst 21 as the estimated NOx amount (NOx_est) based on the exhaust information on the exhaust discharged from the engine 10 and the catalyst information on the NOx catalyst 21. Do. Then, the detected NOx amount (NOx_sens) detected by the downstream side NOx sensor 24 is compared with the estimated NOx amount (NOx_est), and based on the comparison result, the ozone supply amount control by the ozone supply device and the ozone supply device Conduct an abnormality diagnosis.
  • FIG. 3 is a flowchart showing a control procedure of ozone supply, and the present process is performed by the ECU 40 at a predetermined cycle.
  • step S ⁇ b> 11 it is determined whether or not the operating state of the engine 10 is stable without being transient. In this case, it may be determined that the engine operating state is stable based on the fact that changes in engine rotational speed and load within a predetermined period are less than or equal to a predetermined value. Further, for example, it may be configured to determine that the driving state of the vehicle is stable based on the accelerator operation amount.
  • step S11 is denied, it progresses to step S12, and when step S11 is affirmed, it progresses to step S13.
  • step S12 the air pump 32 and the ozone generator 33 are operated with a predetermined control command value in order to supply the exhaust pipe 12 with a predetermined predetermined amount of ozone.
  • step S11 is denied, abnormality diagnosis of an ozone supply apparatus is not implemented.
  • step S13 ozone amount information indicating the amount of ozone supplied from the ozone generator 33 into the exhaust pipe 12 through the supply pipe 31 is acquired.
  • the amount of ozone may be estimated from the voltage applied to the electrodes of the ozone generator 33 and the power consumption.
  • the amount of ozone may be calculated in consideration of the amount of air blown by the air pump 32.
  • step S14 exhaust information on the exhaust exhausted from the engine 10 is acquired.
  • the exhaust information includes, for example, an exhaust NOx amount indicating the amount of NOx exhausted from the engine 10, and an exhaust parameter such as an exhaust flow rate and an exhaust temperature.
  • the exhaust NOx amount is calculated by the detection signal of the upstream NOx sensor 22, the exhaust flow rate is calculated by the detection signal of the air amount sensor 18, and the exhaust temperature is calculated by the detection signal of the exhaust temperature sensor 23.
  • step S15 catalyst information on the NOx catalyst 21 is acquired.
  • the catalyst information includes, for example, catalyst parameters such as the temperature of the NOx catalyst 21 and the amount of stored NOx stored in the NOx catalyst 21.
  • the catalyst temperature is calculated by the detection signal of the catalyst temperature sensor 25, and the stored NOx amount is calculated by estimation from the operation history of the engine 10 and the like.
  • the stored NOx amount may be estimated based on the number of fuel injections after the rich combustion has been performed and the fuel injection amount.
  • step S16 the NOx amount discharged downstream of the NOx catalyst 21 is calculated as the estimated NOx amount (NOx_est) based on the ozone amount information, the exhaust information and the catalyst information acquired in the above steps S13 to S15.
  • the relationship between the ozone amount information, the exhaust information, various parameters in the catalyst information, and the estimated NOx amount (NOx_est) will be described.
  • FIG. 4A shows the relationship between the amount of ozone as ozone amount information and the estimated amount of NOx (NOx_est).
  • the ECU 40 calculates a larger value as the estimated NOx amount (NOx_est) as the ozone amount is smaller.
  • FIG. 4B shows the relationship between the exhaust NOx amount as exhaust information and the estimated NOx amount (NOx_est).
  • the ECU 40 calculates a larger value as the estimated NOx amount (NOx_est) as the exhaust NOx amount is larger.
  • FIG. 4C shows the relationship between the exhaust gas flow rate as exhaust gas information and the estimated NOx amount (NOx_est).
  • the ECU 40 calculates a larger value as the estimated NOx amount (NOx_est) as the exhaust gas flow rate is larger.
  • exhaust pressure it is also possible to use exhaust pressure as exhaust information instead of the exhaust flow rate. In this case, as the exhaust pressure is higher, a larger value is calculated as the estimated NOx amount (NOx_est).
  • FIG. 4D shows the relationship between the exhaust gas temperature as exhaust gas information and the estimated NOx amount (NOx_est).
  • the ECU 40 calculates a larger value as the estimated NOx amount (NOx_est) as the exhaust gas temperature is lower.
  • FIG. 4E shows the relationship between the catalyst temperature as catalyst information and the estimated NOx amount (NOx_est).
  • the ECU 40 calculates a larger value as the estimated NOx amount (NOx_est) as the catalyst temperature is lower.
  • the relationship between the catalyst temperature and the estimated NOx amount (NOx_est) depends on the amount of ozone, the relationship may be determined in consideration of the amount of ozone. In this case, as indicated by the broken line in FIG. 4E, the smaller the ozone amount, the larger the estimated NOx amount (NOx_est), and the larger the inclination (negative inclination) of the estimated NOx amount (NOx_est) with respect to the catalyst temperature. It is good to do.
  • FIG. 4F shows the relationship between the stored NOx amount as catalyst information and the estimated NOx amount (NOx_est).
  • the ECU 40 calculates a larger value as the estimated NOx amount (NOx_est) as the stored NOx amount is larger.
  • the relationships shown in FIGS. 4 (a) to 4 (f) may be determined in advance as maps or mathematical expressions, and the estimated NOx amount (NOx_est) can be calculated by substituting the numerical values of the respective parameters into the maps or mathematical expressions. It is good.
  • the estimated NOx amount (NOx_est) may be calculated using any one or two of the exhaust NOx amount, the exhaust flow rate, and the exhaust temperature as the exhaust information. Further, the estimated NOx amount (NOx_est) may be calculated using either the catalyst temperature or the stored NOx amount as catalyst information. Furthermore, the estimated NOx amount (NOx_est) may be calculated using any one or two of the ozone amount information, the exhaust information, and the catalyst information.
  • step S17 the detected NOx amount (NOx_sens) detected by the downstream side NOx sensor 24 is acquired.
  • the detected NOx amount (NOx_sens) corresponds to the actual NOx amount on the downstream side of the NOx catalyst 21.
  • a predetermined threshold value TH it is determined whether the NOx amount on the catalyst downstream side is excessive with respect to the amount of ozone (the original amount of ozone) of the soot supplied from the ozone supply device.
  • the threshold TH may be determined based on the allowable NOx amount downstream of the NOx catalyst 21, that is, the allowable NOx amount downstream of the catalyst, which is determined based on an environmental standard or the like.
  • the correction amount may be a predetermined constant increase correction value other than being variably set according to the difference ⁇ Y.
  • the correction amount may be set using the relationship shown in FIG. According to FIG. 5B, when the difference ⁇ Y is positive, that is, when NOx_sens> NOx_est, the ozone correction amount is increased by the positive correction amount, and when the difference ⁇ Y is negative, that is, NOx_sens ⁇ NOx_est. In this case, the amount of ozone supplied is corrected to decrease by the negative correction amount.
  • an upper limit guard process is performed on the newly calculated ozone supply amount. Specifically, it is determined whether the new ozone supply amount has reached a predetermined upper limit value, and when the upper limit value has been reached, the ozone supply amount is limited by the upper limit value. Thus, the ozone supply amount is feedback controlled in accordance with the difference ⁇ Y while being limited within the range up to the upper limit value.
  • the applied voltage may be increased.
  • the air flow rate of the air pump 32 may be increased.
  • step S21 If ⁇ Y ⁇ TH, the process proceeds to step S21, and it is determined that an abnormality occurs in the ozone supply device.
  • step S22 a warning by a failure warning lamp or voice is performed to notify that the ozone supply device is abnormal.
  • the ozone supply by the ozone supply device is stopped.
  • the detected NOx amount (NOx_sens) detected by the downstream side NOx sensor 24 is acquired while the engine 10 is in operation and ozone is supplied by the ozone supply device, and the detected NOx amount (NOx_sens) is obtained. Ozone supply control and abnormality diagnosis were implemented. As a result, while monitoring that the actual NOx purification rate has dropped, ozone supply amount control and abnormality diagnosis can be properly implemented. As a result, it is possible to properly supply ozone, and thus to realize appropriate NOx purification.
  • the NOx amount on the catalyst downstream side is calculated as an estimated NOx amount (NOx_est), and the estimated NOx amount (NOx_est) and the downstream NOx sensor 24 are used.
  • NOx_sens Based on the comparison result with the detected NOx amount (NOx_sens), ozone supply amount control and abnormality diagnosis of the ozone supply device are performed. As a result, even if the state of the exhaust gas or the NOx catalyst 21 changes in accordance with the engine operating state or the like, the ozone supply amount control and the abnormality diagnosis can be properly implemented.
  • the estimated NOx amount (NOx_est) is calculated based on the exhaust NOx amount from the engine 10, the exhaust flow rate, and the exhaust temperature, the accuracy of ozone supply amount control and the accuracy of abnormality diagnosis, etc. It is possible to suppress the inconvenience of lowering.
  • the estimated NOx amount (NOx_est) is calculated based on the temperature of the NOx catalyst 21 and the amount of absorbed NOx of the NOx catalyst 21, the accuracy of ozone supply control and the accuracy of abnormality diagnosis, etc., along with the change of each parameter It is possible to suppress the inconvenience of lowering.
  • the ozone amount supplied to the exhaust pipe 12 is acquired and the estimated NOx amount (NOx_est) is calculated based on the ozone amount, the accuracy of ozone supply amount control and the accuracy of abnormality diagnosis according to the change of the amount of ozone It is possible to suppress the inconvenience of being lowered.
  • the ozone supply amount control is performed based on the difference ⁇ Y, and the difference ⁇ Y is larger than the threshold TH was configured to carry out an abnormality diagnosis of the ozone supply device.
  • ozone supply amount control and abnormality diagnosis can be properly performed on the ozone supply device as necessary. In this case, it is possible to obtain stable purification performance of the NOx catalyst 21 by ozone supply amount control before the ozone supply device is determined to be abnormal.
  • the ozone supply amount is controlled based on the detected NOx amount (NOx_sens) within the range until the ozone supply amount reaches the predetermined upper limit value, and the ozone supply device is controlled based on the ozone supply amount being the upper limit value. It was set up to carry out an abnormality diagnosis. In this case, since the maximum ozone supply is performed within the control range in which the ozone can be supplied, and the abnormality diagnosis of the ozone supply device is performed under the state where the maximum ozone supply is performed, the ozone An appropriate abnormality diagnosis can be performed while supplying as much as possible.
  • the engine 10 When it is satisfied that the operating state of the engine 10 is not transient but stable, it is configured to carry out ozone supply control and abnormality diagnosis. Therefore, the control accuracy of ozone supply control can be improved. In addition, erroneous diagnosis in abnormality diagnosis can be suppressed, and diagnostic accuracy can be improved.
  • the ECU 40 is configured to perform the ozone supply amount control and the abnormality diagnosis. However, only one of them may be implemented. For example, the ECU 40 performs ozone supply amount control based on the difference ⁇ Y between the detected NOx amount (NOx_sens) and the estimated NOx amount (NOx_est). Alternatively, the ECU 40 carries out an abnormality diagnosis of the ozone supply device based on the difference ⁇ Y between the detected NOx amount (NOx_sens) and the estimated NOx amount (NOx_est).
  • the ozone supply amount control and abnormality diagnosis are performed based on the difference ⁇ Y between the detected NOx amount (NOx_sens) and the estimated NOx amount (NOx_est), but this is changed to detect the detected NOx amount (NOx_sens)
  • the ozone supply amount control and the abnormality diagnosis may be performed using only the detected NOx amount (NOx_sens) among the estimated NOx amount (NOx_est) and the estimated NOx amount (NOx_est).
  • the ozone supply device supplies a fixed amount of ozone. Then, the ECU 40 sets the ozone supply amount based on the detected NOx amount (NOx_sens).
  • the ECU 40 increases the ozone supply amount as the detected NOx amount (NOx_sens) is larger.
  • the detected NOx amount (NOx_sens) is equal to or more than a predetermined value, it is determined that an abnormality occurs in the ozone supply device.
  • the exhaust gas purification system is not limited to that shown in FIG. 1, and may have an oxidation catalyst upstream of the NOx catalyst 21 or DPF downstream of the NOx catalyst 21 or DPF with a catalyst. .

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Health & Medical Sciences (AREA)
  • Organic Chemistry (AREA)
  • Toxicology (AREA)
  • Environmental & Geological Engineering (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • General Chemical & Material Sciences (AREA)
  • Inorganic Chemistry (AREA)
  • Analytical Chemistry (AREA)
  • Biomedical Technology (AREA)
  • Exhaust Gas After Treatment (AREA)
  • Exhaust Gas Treatment By Means Of Catalyst (AREA)
  • Oxygen, Ozone, And Oxides In General (AREA)
PCT/JP2018/030876 2017-08-23 2018-08-21 排気浄化システムの制御装置 Ceased WO2019039481A1 (ja)

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DE112018004733.4T DE112018004733T5 (de) 2017-08-23 2018-08-21 Steuervorrichtung für ein Abgasreinigungssystem
US16/783,251 US20200173328A1 (en) 2017-08-23 2020-02-06 Controller for exhaust gas purification system

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JP2017-160333 2017-08-23

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US10865689B2 (en) * 2018-09-21 2020-12-15 Cummins Inc. Systems and methods for diagnosis of NOx storage catalyst
EP4170139B1 (en) * 2021-10-19 2024-05-01 Volvo Penta Corporation Method for predicting urea crystal build-up in an engine system

Citations (3)

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Publication number Priority date Publication date Assignee Title
JP2009281290A (ja) * 2008-05-22 2009-12-03 Toyota Motor Corp 内燃機関の排気ガス浄化装置
JP2010031730A (ja) * 2008-07-29 2010-02-12 Toyota Motor Corp 内燃機関の排気浄化装置
JP2016079872A (ja) * 2014-10-15 2016-05-16 株式会社デンソー オゾン供給装置

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JP2017160333A (ja) 2016-03-09 2017-09-14 旭化成株式会社 ポリアセタールコポリマー、コポリマーの製造方法、およびポリアセタール樹脂組成物

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2009281290A (ja) * 2008-05-22 2009-12-03 Toyota Motor Corp 内燃機関の排気ガス浄化装置
JP2010031730A (ja) * 2008-07-29 2010-02-12 Toyota Motor Corp 内燃機関の排気浄化装置
JP2016079872A (ja) * 2014-10-15 2016-05-16 株式会社デンソー オゾン供給装置

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