WO2016098895A1 - SYSTÈME DE PURIFICATION D'ÉCHAPPEMENT ET PROCÉDÉ DE RÉCUPÉRATION DE CAPACITÉ DE PURIFICATION DE NOx - Google Patents

SYSTÈME DE PURIFICATION D'ÉCHAPPEMENT ET PROCÉDÉ DE RÉCUPÉRATION DE CAPACITÉ DE PURIFICATION DE NOx Download PDF

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Publication number
WO2016098895A1
WO2016098895A1 PCT/JP2015/085549 JP2015085549W WO2016098895A1 WO 2016098895 A1 WO2016098895 A1 WO 2016098895A1 JP 2015085549 W JP2015085549 W JP 2015085549W WO 2016098895 A1 WO2016098895 A1 WO 2016098895A1
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Prior art keywords
exhaust
regeneration
nox
rotational speed
internal combustion
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PCT/JP2015/085549
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English (en)
Japanese (ja)
Inventor
輝男 中田
隆行 坂本
長岡　大治
智宏 是永
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いすゞ自動車株式会社
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Publication of WO2016098895A1 publication Critical patent/WO2016098895A1/fr

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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
    • 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
    • B01D53/96—Regeneration, reactivation or recycling of reactants
    • 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
    • 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
    • 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
    • F01N3/36—Arrangements for supply of additional fuel
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D45/00—Electrical control not provided for in groups F02D41/00 - F02D43/00

Definitions

  • the present invention relates to an exhaust purification system and a NOx purification capacity recovery method.
  • a NOx occlusion reduction type catalyst is known as a catalyst for reducing and purifying nitrogen compounds (NOx) in exhaust gas discharged from an internal combustion engine.
  • the NOx occlusion reduction catalyst occludes NOx contained in the exhaust when the exhaust is in a lean atmosphere, and harmless NOx occluded by hydrocarbons contained in the exhaust when the exhaust is in a rich atmosphere. And release. For this reason, when the NOx occlusion amount of the catalyst reaches a predetermined amount, so-called NOx purging that makes the exhaust gas rich by exhaust pipe injection or post injection needs to be performed periodically in order to recover the NOx occlusion capacity ( For example, see Patent Document 1).
  • the NOx occlusion reduction type catalyst also occludes sulfur oxide (hereinafter referred to as SOx) contained in the exhaust gas.
  • SOx sulfur oxide
  • the SOx occlusion amount increases, there is a problem that the NOx purification ability of the NOx occlusion reduction type catalyst is lowered. For this reason, when the SOx occlusion amount reaches a predetermined amount, unburned fuel is injected into the upstream oxidation catalyst by exhaust pipe injection or post injection so that SOx is released from the NOx occlusion reduction catalyst and recovered from S poisoning. Therefore, it is necessary to periodically perform a so-called SOx purge for raising the exhaust temperature to the SOx separation temperature (see, for example, Patent Document 2).
  • Patent Document 3 a technique for maintaining the temperature of the catalyst within an appropriate range has been proposed for performing control for decomposing and removing SOx and the like deposited on the NOx catalyst (for example, Patent Document 3). reference).
  • the exhaust purification system and the NOx purification capacity recovery method of the present disclosure are intended to effectively prevent a rapid increase in engine temperature during the regeneration process of the catalyst.
  • An exhaust purification system of the present disclosure is provided in an exhaust passage of an internal combustion engine to reduce and purify NOx in exhaust, and a regeneration that restores the NOx purification ability of the NOx reduction catalyst by making exhaust rich.
  • Regeneration control means for executing processing, rotation speed acquisition means for acquiring the rotation speed of the internal combustion engine, and when the rotation speed acquired by the rotation speed acquisition means is higher than a predetermined upper limit rotation speed threshold, the regeneration control Reproduction prohibiting means for prohibiting execution of the reproduction processing by the means.
  • An exhaust purification system of the present disclosure is provided in an exhaust passage of an internal combustion engine, and a NOx reduction catalyst that reduces and purifies NOx contained in the exhaust from the internal combustion engine, and a rotation that detects the rotational speed of the internal combustion engine.
  • An exhaust purification system comprising a speed sensor and a control unit that controls at least one of the intake flow rate and the fuel injection amount of the internal combustion engine, the control unit operating to perform the following processing: A regeneration process for restoring the NOx purification ability of the NOx reduction catalyst by controlling at least one of the intake flow rate and the fuel injection amount to bring the exhaust into a rich state; A comparison process comparing the rotation speed detected by the rotation speed sensor with a preset upper limit rotation speed threshold; and the rotation speed becomes higher than the upper limit rotation speed threshold during the reproduction process. Sometimes interruption processing for interrupting execution of the reproduction processing.
  • An NOx purification capacity recovery method includes an internal combustion engine, an exhaust aftertreatment device that is disposed in an exhaust passage of the internal combustion engine and includes an oxidation catalyst and a NOx reduction catalyst that are sequentially disposed from the upstream side of the exhaust passage.
  • a NOx purification capacity recovery method in an exhaust purification system comprising: the NOx reduction type by controlling at least one of the intake flow rate and fuel injection amount of the internal combustion engine to bring the exhaust into a rich state
  • a regeneration process for recovering the NOx purification capacity of the catalyst is interrupted when the rotational speed of the internal combustion engine becomes higher than a preset upper limit rotational speed threshold value during the regeneration process. Including interruption processing.
  • FIG. 1 is an overall configuration diagram showing an exhaust gas purification system and an internal combustion engine control apparatus according to the present embodiment.
  • FIG. 2 is a timing chart for explaining the SOx purge control according to the present embodiment.
  • FIG. 3 is a block diagram showing the MAF target value setting process during SOx purge lean control according to the present embodiment.
  • FIG. 4 is a block diagram showing a target injection amount setting process during SOx purge rich control according to the present embodiment.
  • FIG. 5 is a timing chart illustrating the catalyst temperature adjustment control of the SOx purge control according to the present embodiment.
  • FIG. 6 is a block diagram showing a prohibition process of SOx purge control according to this embodiment.
  • FIG. 7 is a block diagram showing the injection amount learning correction processing of the injector according to the present embodiment.
  • FIG. 8 is a flowchart for explaining learning correction coefficient calculation processing according to the present embodiment.
  • FIG. 9 is a block diagram showing MAF correction coefficient setting processing according to the present embodiment.
  • each cylinder of a diesel engine (hereinafter simply referred to as an engine) 10 is provided with an injector 11 that directly injects high-pressure fuel accumulated in a common rail (not shown) into each cylinder.
  • the fuel injection amount and fuel injection timing of each injector 11 are controlled in accordance with an instruction signal input from an electronic control unit (hereinafter referred to as ECU) 50.
  • ECU electronice control unit
  • An intake passage 12 for introducing fresh air is connected to the intake manifold 10A of the engine 10, and an exhaust passage 13 for connecting exhaust to the outside is connected to the exhaust manifold 10B.
  • an air cleaner 14 an intake air amount sensor (hereinafter referred to as MAF (Mass Air Flow) sensor) 40, a compressor 20A of the variable displacement supercharger 20, an intercooler 15, an intake throttle valve are arranged in order from the intake upstream side. 16 etc. are provided.
  • the exhaust passage 13 is provided with a turbine 20B of the variable displacement supercharger 20, an exhaust aftertreatment device 30 and the like in order from the exhaust upstream side.
  • the engine 10 is provided with an engine speed sensor 41, an accelerator opening sensor 42, and a boost pressure sensor 46.
  • the engine speed sensor 41 detects the speed of the engine 10 and outputs a signal indicating the speed to the ECU 50.
  • the term “the number of rotations” is used to mean “the number of rotations per unit time” and “the rotation speed”.
  • the MAF sensor 40 that measures and detects the mass flow rate is used as a sensor that measures and detects the intake air amount of the engine (intake flow rate (Suction Air Flow)).
  • intake flow rate Sudden Air Flow
  • a different type of flow rate (AirFFlow) sensor from the MAF sensor 40 or a means in place of the flow rate sensor may be used.
  • the EGR device 21 includes an EGR passage 22 that connects the exhaust manifold 10B and the intake manifold 10A, an EGR cooler 23 that cools the EGR gas, and an EGR valve 24 that adjusts the EGR amount.
  • the exhaust aftertreatment device 30 is configured by arranging an oxidation catalyst 31, a NOx occlusion reduction type catalyst 32, and a particulate filter (hereinafter simply referred to as a filter) 33 in order from the exhaust upstream side in a case 30A. Further, exhaust pipe injection for injecting unburned fuel (mainly hydrocarbon (HC)) into the exhaust passage 13 in the exhaust passage 13 upstream of the oxidation catalyst 31 in response to an instruction signal input from the ECU 50. A device 34 is provided.
  • unburned fuel mainly hydrocarbon (HC)
  • the oxidation catalyst 31 is formed, for example, by carrying an oxidation catalyst component on the surface of a ceramic carrier such as a honeycomb structure.
  • a ceramic carrier such as a honeycomb structure.
  • the NOx occlusion reduction type catalyst 32 is formed, for example, by supporting an alkali metal or the like on the surface of a ceramic carrier such as a honeycomb structure.
  • the NOx occlusion reduction type catalyst 32 occludes NOx in the exhaust when the exhaust air-fuel ratio is in a lean state, and occludes with a reducing agent (HC or the like) contained in the exhaust when the exhaust air-fuel ratio is in a rich state. NOx is reduced and purified.
  • the filter 33 is formed, for example, by arranging a large number of cells partitioned by porous partition walls along the flow direction of the exhaust gas and alternately plugging the upstream side and the downstream side of these cells. .
  • the filter 33 collects particulate matter (PM) in the exhaust gas in the pores and surfaces of the partition walls, and when the estimated amount of PM deposition reaches a predetermined amount, so-called filter forced regeneration is performed to remove it.
  • Filter forced regeneration is performed by supplying unburned fuel to the upstream side oxidation catalyst 31 by exhaust pipe injection or post injection, and raising the exhaust temperature flowing into the filter 33 to the PM combustion temperature.
  • the first exhaust temperature sensor 43 is provided on the upstream side of the oxidation catalyst 31 and detects the exhaust temperature flowing into the oxidation catalyst 31.
  • the second exhaust temperature sensor 44 is provided between the NOx storage reduction catalyst 32 and the filter 33 and detects the exhaust temperature flowing into the filter 33.
  • the NOx / lambda sensor 45 is provided on the downstream side of the filter 33, and detects the NOx value and lambda value (hereinafter also referred to as excess air ratio) of the exhaust gas that has passed through the NOx storage reduction catalyst 32.
  • the ECU 50 performs various controls of the engine 10 and the like, and includes a known CPU, ROM, RAM, input port, output port, and the like. In order to perform these various controls, the sensor values of the sensors 40 to 46 are input to the ECU 50. Further, the ECU 50 includes a forced filter regeneration control unit 51, an SOx purge control unit 60, an SOx purge prohibition unit 70, an MAF follow-up control unit 80, an injection amount learning correction unit 90, and an MAF correction coefficient calculation unit 95. As part of functional elements. Each of these functional elements will be described as being included in the ECU 50 which is an integral hardware, but any one of these may be provided in separate hardware.
  • the filter forced regeneration control unit 51 estimates the PM accumulation amount of the filter 33 from the travel distance of the vehicle or the differential pressure across the filter detected by a differential pressure sensor (not shown), and the estimated PM accumulation amount has a predetermined upper limit threshold. If it exceeds, the forced regeneration flag F DPF is turned on (see time t 1 in FIG. 2). When the forced regeneration flag F DPF is turned on, an instruction signal for causing the exhaust pipe injection device 34 to execute exhaust pipe injection is transmitted, or an instruction signal for causing each injector 11 to perform post injection is transmitted. The exhaust temperature is raised to the PM combustion temperature (for example, about 550 ° C.). The forced regeneration flag F DPF is turned off when the PM accumulation estimated amount falls to a predetermined lower limit threshold (see time t 2 in FIG. 2).
  • the SOx purge control unit 60 is an example of the regeneration control means of the present invention, and makes the exhaust gas rich and raises the exhaust gas temperature to a sulfur desorption temperature (for example, about 600 ° C.). Control to recover from SOx poisoning (hereinafter, this control is referred to as SOx purge control) is executed.
  • FIG. 2 shows a timing chart of the SOx purge control of this embodiment.
  • SOx purge flag F SP to start SOx purge control SOx purge prohibition flag F Pro_SP described later is off, the forced regeneration flag F DPF is turned on when it is turned off (FIG. see time t 2 of 2).
  • the enrichment by the SOx purge control is performed by adjusting the excess air ratio to the lean side from the theoretical air-fuel ratio equivalent value (about 1.0) from the steady operation (for example, about 1.5) by the air system control.
  • SOx purge lean control for reducing to 1 target excess air ratio (for example, about 1.3) and injection system control to reduce the excess air ratio from the first target excess air ratio to the second target excess air ratio on the rich side (for example, about 0) This is realized by using together with the SOx purge rich control that lowers to .9). Details of the SOx purge lean control and the SOx purge rich control will be described below.
  • FIG. 3 is a block diagram showing a process for setting the MAF target value MAF SPL_Trgt during SOx purge lean control.
  • the first target excess air ratio setting map 61 is a map that is referred to based on the engine speed Ne and the accelerator opening Q (the fuel injection amount of the engine 10), and the engine speed Ne, the accelerator opening Q, A target value ⁇ SPL_Trgt (first target air excess rate) at the time of SOx purge lean control corresponding to is preset based on experiments or the like.
  • the excess air ratio target value ⁇ SPL_Trgt at the time of SOx purge lean control is read from the first target excess air ratio setting map 61 using the engine speed Ne and the accelerator opening Q as input signals, and the MAF target value calculation unit 62 Entered. Further, the MAF target value calculation unit 62 calculates the MAF target value MAF SPL_Trgt at the time of SOx purge lean control based on the following formula (1).
  • Equation (1) Q fnl_corrd is a learning-corrected fuel injection amount (excluding post-injection) described later, Ro Fuel is a fuel specific gravity, AFR sto is a stoichiometric air-fuel ratio, and Maf_corr is a MAF correction coefficient described later. Yes.
  • MAF target value MAF SPL_Trgt calculated by the MAF target value calculation unit 62, when the SOx purge flag F SP is turned on (see time t 2 in FIG. 2) is input to the lamp unit 63.
  • the ramp processing unit 63 reads the ramp coefficient from the + ramp coefficient map 63A and the ⁇ ramp coefficient map 63B using the engine speed Ne and the accelerator opening Q as input signals, and calculates the MAF target ramp value MAF SPL_Trgt_Ramp to which the ramp coefficient is added. Input to the valve control unit 64.
  • the valve control unit 64 throttles the intake throttle valve 16 to the close side and feeds back the EGR valve 24 to the open side so that the actual MAF value MAF Act input from the MAF sensor 40 becomes the MAF target ramp value MAF SPL_Trgt_Ramp. Execute control.
  • the MAF target value MAF SPL_Trgt is set based on the excess air ratio target value ⁇ SPL_Trgt read from the first target excess air ratio setting map 61 and the fuel injection amount of each injector 11.
  • the air system operation is feedback controlled based on the MAF target value MAF SPL_Trgt .
  • the MAF target value MAF SPL_Trgt can be set by feedforward control, and the aging deterioration and characteristic change of each injector 11 can be achieved. The influence of individual differences can be effectively eliminated.
  • FIG. 4 is a block diagram showing processing for setting the target injection amount Q SPR_Trgt (injection amount per unit time) of exhaust pipe injection or post injection in SOx purge rich control.
  • the second target excess air ratio setting map 65 is a map that is referred to based on the engine speed Ne and the accelerator opening Q, and at the time of SOx purge rich control corresponding to the engine speed Ne and the accelerator opening Q.
  • the air excess rate target value ⁇ SPR_Trgt (second target air excess rate) is set in advance based on experiments or the like.
  • the excess air ratio target value ⁇ SPR_Trgt at the time of SOx purge rich control is read from the second target excess air ratio setting map 65 using the engine speed Ne and the accelerator opening Q as input signals, and an injection quantity target value calculation unit 66. Further, the injection amount target value calculation unit 66 calculates the target injection amount Q SPR_Trgt at the time of SOx purge rich control based on the following formula (2).
  • MAF SPL_Trgt is the MAF target value at the time of SOx purge lean, and is input from the MAF target value calculation unit 62 described above.
  • Q fnlRaw_corrd is a fuel injection amount (excluding post-injection) after application of learning corrected MAF follow-up control described later,
  • Ro Fuel is fuel specific gravity
  • AFR sto is a stoichiometric air-fuel ratio
  • Maf_corr is a MAF correction coefficient described later. Show.
  • the target injection amount Q SPR_Trgt calculated by the injection amount target value calculation unit 66 is transmitted as an injection instruction signal to the exhaust pipe injector 34 or each injector 11 when a SOx purge rich flag F SPR described later is turned on.
  • the target injection amount Q SPR_Trgt is set based on the air excess rate target value ⁇ SPR_Trgt read from the second target air excess rate setting map 65 and the fuel injection amount of each injector 11. It has become.
  • the sensor value of the lambda sensor is not used.
  • the exhaust can be effectively reduced to a desired excess air ratio required for SOx purge rich control.
  • the exhaust temperature (hereinafter also referred to as catalyst temperature) flowing into the NOx occlusion reduction type catalyst 32 during the SOx purge control is the SOx for performing exhaust pipe injection or post injection as shown at times t 2 to t 4 in FIG.
  • the purge rich flag F SPR is controlled by alternately switching on / off (rich / lean).
  • the SOx purge rich flag F SPR is turned off, the catalyst temperature is lowered by stopping the exhaust pipe injection or the post injection (hereinafter, this period is referred to as an interval TF_INT ).
  • the injection period TF_INJ is set by reading values corresponding to the engine speed Ne and the accelerator opening Q from an injection period setting map (not shown) created in advance by experiments or the like.
  • an injection period required to reliably reduce the excess air ratio of exhaust gas obtained in advance through experiments or the like to the second target excess air ratio is set according to the operating state of the engine 10. ing.
  • the interval TF_INT is set by feedback control when the SOx purge rich flag F SPR at which the catalyst temperature is highest is switched from on to off. Specifically, the proportional control for changing the input signal in proportion to the deviation ⁇ T between the target catalyst temperature and the estimated catalyst temperature when the SOx purge rich flag F SPR is turned off, and the time integral value of the deviation ⁇ T are proportional. This is processed by PID control constituted by integral control for changing the input signal and differential control for changing the input signal in proportion to the time differential value of the deviation ⁇ T.
  • the target catalyst temperature is set at a temperature at which SOx can be removed from the NOx storage reduction catalyst 32.
  • the estimated catalyst temperature is, for example, the inlet temperature of the oxidation catalyst 31 detected by the first exhaust temperature sensor 43, and the oxidation catalyst 31. It may be estimated based on the exothermic reaction in the NOx occlusion reduction type catalyst 32 or the like.
  • the injection period T F_INJ for raising the catalyst temperature and lowering the excess air ratio to the second target excess air ratio is set from a map referred to based on the operating state of the engine 10,
  • the interval TF_INT for lowering the catalyst temperature is processed by PID control. This makes it possible to reliably reduce the excess air ratio to the target excess ratio while effectively maintaining the catalyst temperature during the SOx purge control within a desired temperature range necessary for the purge.
  • FIG. 6 is a block diagram showing the SOx purge execution prohibition process by the SOx purge prohibition unit 70.
  • the SOx purge prohibiting unit 70 is a regeneration prohibiting means of the present invention, and (1) when the engine speed Ne is higher than a predetermined upper limit speed threshold, (2) the engine speed Ne is a predetermined lower limit speed threshold. Is lower than (3) the fuel injection amount of the injector 11 is greater than a predetermined upper limit injection amount threshold, and (4) the catalyst temperature of the NOx storage reduction catalyst 32 is lower than the predetermined catalyst activation temperature.
  • SOx purge control (1) SOx purge flag F from on the SP injection quantity of the exhaust pipe injection or post injection accumulated, when the amount of the cumulative injected has reached the predetermined upper limit threshold amount, of (2) SOx purge control When the elapsed time counted from the start reaches a predetermined upper threshold time, (3) calculation is performed based on a predetermined model formula including the operating state of the engine 10 and the sensor value of the NOx / lambda sensor 45 as input signals.
  • SOx purge flag F SP is terminated by turning off the (time t 4 in FIG. 2 , reference time t n in FIG. 5).
  • the SOx purge control end condition is provided with the upper limit of the cumulative injection amount and the elapsed time
  • the fuel consumption amount when the SOx purge does not progress due to a decrease in the exhaust temperature or the like. Can be effectively prevented from becoming excessive.
  • the MAF follow-up control unit 80 includes (1) a period for switching from a lean state in normal operation to a rich state by SOx purge control or NOx purge control, and (2) lean in normal operation from a rich state by SOx purge control or NOx purge control. During the switching period to the state, control for correcting the fuel injection timing and the fuel injection amount of each injector 11 in accordance with the MAF change (hereinafter, this control is referred to as MAF follow-up control) is executed.
  • the injection amount learning correction unit 90 includes a learning correction coefficient calculation unit 91 and an injection amount correction unit 92.
  • the learning correction coefficient calculation unit 91 is based on the error ⁇ between the actual lambda value ⁇ Act detected by the NOx / lambda sensor 45 during the lean operation of the engine 10 and the estimated lambda value ⁇ Est and the learning correction coefficient F for the fuel injection amount. Calculate Corr .
  • the HC concentration in the exhaust is very low, so that the change in the exhaust lambda value due to the oxidation reaction of HC at the oxidation catalyst 33 is negligibly small. Therefore, the actual lambda value ⁇ Act in the exhaust gas that passes through the oxidation catalyst 31 and is detected by the downstream NOx / lambda sensor 45 matches the estimated lambda value ⁇ Est in the exhaust gas exhausted from the engine 10.
  • step S300 based on the engine speed Ne and the accelerator opening Q, it is determined whether or not the engine 10 is in a lean operation state. If it is in the lean operation state, the process proceeds to step S310 to start the calculation of the learning correction coefficient.
  • the estimated lambda value ⁇ Est is estimated and calculated from the operating state of the engine 10 according to the engine speed Ne and the accelerator opening Q. Further, the correction sensitivity coefficient K 2 is read from the correction sensitivity coefficient map 91A shown in FIG. 7 using the actual lambda value ⁇ Act detected by the NOx / lambda sensor 45 as an input signal.
  • step S320 it is determined whether or not the absolute value
  • step S330 it is determined whether the learning prohibition flag FPro is off.
  • Whether or not the engine 10 is in a transient operation state is determined when, for example, the time change amount is larger than a predetermined threshold based on the time change amount of the actual lambda value ⁇ Act detected by the NOx / lambda sensor 45. What is necessary is just to determine with a transient operation state.
  • step S340 the learning value map 91B (see FIG. 7) referred to based on the engine speed Ne and the accelerator opening Q is updated to the learning value F CorrAdpt calculated in step S310. More specifically, on the learning value map 91B, a plurality of learning areas divided according to the engine speed Ne and the accelerator opening Q are set. These learning regions are preferably set to have a narrower range as the region is used more frequently and to be wider as a region is used less frequently. As a result, learning accuracy is improved in regions where the usage frequency is high, and unlearning can be effectively prevented in regions where the usage frequency is low.
  • the injection amount correction unit 92 multiplies each basic injection amount of pilot injection Q Pilot , pre-injection Q Pre , main injection Q Main , after-injection Q After , and post-injection Q Post by a learning correction coefficient F Corr, thereby The injection amount is corrected.
  • the MAF correction coefficient calculation unit 95 sets MAF target value MAF SPL_Trgt and target injection amount Q SPR_Trgt at the time of SOx purge control, and MAF used for setting MAF target value MAF NPL_Trgt and target injection amount Q NPR_Trgt at the time of NOx purge control.
  • a correction coefficient Maf_corr is calculated.
  • the fuel injection amount of each injector 11 is corrected based on the error ⁇ between the actual lambda value ⁇ Act detected by the NOx / lambda sensor 45 and the estimated lambda value ⁇ Est .
  • the factor of error ⁇ is not necessarily only the effect of the difference between the commanded injection amount and the actual injection amount for each injector 11. That is, there is a possibility that the error of not only each injector 11 but also the MAF sensor 40 affects the lambda error ⁇ .
  • FIG. 9 is a block diagram showing the setting process of the MAF correction coefficient Maf_corr by the MAF correction coefficient calculation unit 95.
  • the correction coefficient setting map 96 is a map that is referred to based on the engine speed Ne and the accelerator opening Q.
  • the MAF indicating the sensor characteristics of the MAF sensor 40 corresponding to the engine speed Ne and the accelerator opening Q is shown in FIG.
  • the correction coefficient Maf_corr is set in advance based on experiments or the like.
  • the MAF correction coefficient calculation unit 95 reads the MAF correction coefficient Maf_corr from the correction coefficient setting map 96 using the engine speed Ne and the accelerator opening Q as input signals, and uses the MAF correction coefficient Maf_corr as the MAF target value calculation unit 62 and It transmits to the injection quantity target value calculating part 66.
  • the sensor characteristics of the MAF sensor 40 can be effectively reflected in the settings of the MAF target value MAF SPL_Trgt and the target injection amount Q SPR_Trgt during the SOx purge control.

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  • Chemical Kinetics & Catalysis (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Health & Medical Sciences (AREA)
  • Toxicology (AREA)
  • Analytical Chemistry (AREA)
  • Biomedical Technology (AREA)
  • Environmental & Geological Engineering (AREA)
  • General Chemical & Material Sciences (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Sustainable Development (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Exhaust Gas After Treatment (AREA)
  • Combined Controls Of Internal Combustion Engines (AREA)

Abstract

La présente invention vise à éviter de manière efficace une élévation soudaine de la température d'un moteur au cours d'un traitement de régénération d'un catalyseur. A cet effet, l'invention comporte : un catalyseur de réduction de NOx (32) qui est disposé dans un canal d'échappement (13) d'un moteur à combustion interne (10), et qui réduit et purifie les NOx dans l'échappement; une unité de commande de régénération (60), qui exécute un traitement de régénération, grâce à quoi la capacité de purification de NOx du catalyseur de réduction de NOx (32) est récupérée par enrichissement de l'échappement; un capteur de vitesse de rotation de moteur (41) qui acquiert la vitesse de rotation du moteur à combustion interne; et une unité d'interdiction de régénération (70) qui interdit l'exécution d'un traitement de régénération par l'unité de commande de régénération (60) quand la vitesse de rotation acquise par le capteur de vitesse de rotation de moteur (41) dépasse un seuil de vitesse de rotation de limite supérieure prescrite.
PCT/JP2015/085549 2014-12-19 2015-12-18 SYSTÈME DE PURIFICATION D'ÉCHAPPEMENT ET PROCÉDÉ DE RÉCUPÉRATION DE CAPACITÉ DE PURIFICATION DE NOx WO2016098895A1 (fr)

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JP2019138162A (ja) * 2018-02-06 2019-08-22 マツダ株式会社 エンジンの制御装置
JP2019138160A (ja) * 2018-02-06 2019-08-22 マツダ株式会社 エンジンの制御装置

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003120365A (ja) * 2001-10-05 2003-04-23 Mitsubishi Motors Corp 内燃機関の排気浄化装置
JP2006250036A (ja) * 2005-03-10 2006-09-21 Toyota Motor Corp 内燃機関の排気浄化装置

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4154596B2 (ja) * 2003-06-02 2008-09-24 三菱自動車工業株式会社 内燃機関の排気浄化装置

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003120365A (ja) * 2001-10-05 2003-04-23 Mitsubishi Motors Corp 内燃機関の排気浄化装置
JP2006250036A (ja) * 2005-03-10 2006-09-21 Toyota Motor Corp 内燃機関の排気浄化装置

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