CN108691612A - The emission-control equipment of internal combustion engine - Google Patents

The emission-control equipment of internal combustion engine Download PDF

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Publication number
CN108691612A
CN108691612A CN201810278352.1A CN201810278352A CN108691612A CN 108691612 A CN108691612 A CN 108691612A CN 201810278352 A CN201810278352 A CN 201810278352A CN 108691612 A CN108691612 A CN 108691612A
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China
Prior art keywords
air
fuel ratio
emission control
exhaust emission
control catalyst
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CN201810278352.1A
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Chinese (zh)
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CN108691612B (en
Inventor
依田公
依田公一
青木圭郎
青木圭一郎
林下刚
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Toyota Motor Corp
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Toyota Motor Corp
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Priority claimed from JP2017196290A external-priority patent/JP6614223B2/en
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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
    • F01N3/101—Three-way 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
    • F01N3/10—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
    • F01N11/00—Monitoring or diagnostic devices for exhaust-gas treatment apparatus, e.g. for catalytic activity
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N13/00—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00
    • F01N13/009—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00 having two or more separate purifying devices arranged in series
    • F01N13/0093—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00 having two or more separate purifying devices arranged in series the purifying devices are of the same type
    • 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
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/02—Circuit arrangements for generating control signals
    • F02D41/021—Introducing corrections for particular conditions exterior to the engine
    • F02D41/0235—Introducing corrections for particular conditions exterior to the engine in relation with the state of the exhaust gas treating apparatus
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/02—Circuit arrangements for generating control signals
    • F02D41/14—Introducing closed-loop corrections
    • F02D41/1438—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor
    • F02D41/1444—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the characteristics of the combustion gases
    • F02D41/146—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the characteristics of the combustion gases the characteristics being an NOx content or concentration
    • F02D41/1463—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the characteristics of the combustion gases the characteristics being an NOx content or concentration of the exhaust gases downstream of exhaust gas treatment apparatus
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/02—Circuit arrangements for generating control signals
    • F02D41/14—Introducing closed-loop corrections
    • F02D41/1438—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor
    • F02D41/1444—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the characteristics of the combustion gases
    • F02D41/146—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the characteristics of the combustion gases the characteristics being an NOx content or concentration
    • F02D41/1463—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the characteristics of the combustion gases the characteristics being an NOx content or concentration of the exhaust gases downstream of exhaust gas treatment apparatus
    • F02D41/1465—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the characteristics of the combustion gases the characteristics being an NOx content or concentration of the exhaust gases downstream of exhaust gas treatment apparatus with determination means using an estimation
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/02—Circuit arrangements for generating control signals
    • F02D41/14—Introducing closed-loop corrections
    • F02D41/1438—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor
    • F02D41/1473—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the regulation method
    • F02D41/1475—Regulating the air fuel ratio at a value other than stoichiometry
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/02—Circuit arrangements for generating control signals
    • F02D41/18—Circuit arrangements for generating control signals by measuring intake air flow
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/22—Safety or indicating devices for abnormal conditions
    • 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
    • F01N2340/00—Dimensional characteristics of the exhaust system, e.g. length, diameter or volume of the apparatus; Spatial arrangements of exhaust apparatuses
    • F01N2340/02—Dimensional characteristics of the exhaust system, e.g. length, diameter or volume of the apparatus; Spatial arrangements of exhaust apparatuses characterised by the distance of the apparatus to the engine, or the distance between two exhaust treating apparatuses
    • 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
    • F01N2430/00—Influencing exhaust purification, e.g. starting of catalytic reaction, filter regeneration, or the like, by controlling engine operating characteristics
    • F01N2430/06—Influencing exhaust purification, e.g. starting of catalytic reaction, filter regeneration, or the like, by controlling engine operating characteristics by varying fuel-air ratio, e.g. by enriching fuel-air mixture
    • 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
    • F01N2550/00—Monitoring or diagnosing the deterioration of exhaust systems
    • F01N2550/02—Catalytic activity 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
    • 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
    • F01N2560/025—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics the means being an exhaust gas sensor for measuring or detecting O2, e.g. lambda sensors
    • 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
    • F01N2560/00—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics
    • F01N2560/12—Other sensor principles, e.g. using electro conductivity of substrate or radio frequency
    • 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
    • F01N2900/04—Methods of control or diagnosing
    • F01N2900/0422—Methods of control or diagnosing measuring the elapsed time
    • 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
    • F01N2900/16—Parameters used for exhaust control or diagnosing said parameters being related to the exhaust apparatus, e.g. particulate filter or catalyst
    • F01N2900/1621—Catalyst conversion efficiency
    • 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
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/40—Engine management systems

Abstract

The project of the present invention is to inhibit that misinterpretation occurs when the abnormity diagnosis of cleaning catalyst is exhausted based on NOx sensor output.A kind of emission-control equipment, has:Exhaust emission control catalyst (20), the NOx sensor (46) in exhaust emission control catalyst (20) downstream and air-fuel ratio sensor (41) and control and diagnostic device.Target air-fuel ratio is alternately set as dense air-fuel ratio and dilute air-fuel ratio by control and diagnostic device, also, the switching from dense air-fuel ratio to dilute air-fuel ratio of target air-fuel ratio is carried out when the output air-fuel ratio of air-fuel ratio sensor becomes dense judgement air-fuel ratio or less.Control and diagnostic device exporting the abnormity diagnosis of cleaning catalyst is exhausted based on NOx sensor, and, it is exhausted the abnormity diagnosis of cleaning catalyst when the air-fuel ratio of the exhaust flowed into exhaust emission control catalyst is dense air-fuel ratio, and the abnormity diagnosis when the air-fuel ratio of the exhaust flowed into exhaust emission control catalyst is dilute air-fuel ratio without exhaust emission control catalyst.

Description

The emission-control equipment of internal combustion engine
Technical field
The present invention relates to the emission-control equipments of internal combustion engine.
Background technology
It is previous just known based on the defeated of the NOx sensor configured in the flow direction of exhaust gases downstream side of exhaust emission control catalyst The out emission-control equipment of the internal combustion engine of the exception (degradation) of diagnosis exhaust emission control catalyst.It is net as such exhaust Makeup is set, such as NOx when the known air-fuel ratio in the exhaust flowed out from exhaust emission control catalyst is near chemically correct fuel is passed It is determined as that exhaust emission control catalyst has abnormal emission-control equipment (such as patent text when being worth above on the basis of the output of sensor It offers 1).
Citation
Patent document
Patent document 1:Japanese Unexamined Patent Publication 2002-138821 bulletins
Invention content
However, in emission-control equipment recorded in above-mentioned patent document 1, the row that is flowed into exhaust emission control catalyst The target air-fuel ratio of gas is alternately set as than the air-fuel ratio of richer (hereinafter referred to as " dense air-fuel ratio ") and than reason By the air-fuel ratio (hereinafter referred to as " dilute air-fuel ratio ") of air-fuel ratio.In the emission-control equipment, even if target air-fuel ratio is set It is set to dense air-fuel ratio, also due to the oxygen that exhaust emission control catalyst is absorbed is released, the unburned gas in exhaust emission control catalyst Body is cleaned, therefore the air-fuel ratio for the exhaust flowed out from exhaust emission control catalyst generally becomes chemically correct fuel.Similarly, i.e., Make target air-fuel ratio being set as dilute air-fuel ratio, also due to absorbing oxygen by exhaust emission control catalyst, therefore be catalyzed from exhaust gas purification The air-fuel ratio of the exhaust of agent outflow generally becomes chemically correct fuel.
On the other hand, as described above, in the emission-control equipment recorded in patent document 1, urged from exhaust gas purification When the air-fuel ratio of the exhaust of agent outflow is near chemically correct fuel, the abnormity diagnosis of cleaning catalyst is exhausted.Therefore, exist It is dense air-fuel in the air-fuel ratio of the exhaust flowed into exhaust emission control catalyst in emission-control equipment recorded in patent document 1 Than when and for the abnormity diagnosis of cleaning catalyst also can all be exhausted when dilute air-fuel ratio.
However, if by target empty in the state that the oxygen occlusion amount of exhaust emission control catalyst reduces that oxygen cannot be discharged Combustion then adheres to hydrocarbonization around the catalyst noble metal that exhaust emission control catalyst is supported sometimes than being maintained dense air-fuel ratio Close object (HC) etc..When adhering to HC etc. around catalyst noble metal in this wise, the oxidation of catalyst noble metal reduces (HC poisonings).If the target air-fuel ratio of the exhaust flowed into exhaust emission control catalyst is set as dilute sky in such a state Fire ratio, then since HC poisonings have occurred in exhaust emission control catalyst, so while exhaust emission control catalyst itself does not deteriorate significantly, It is possible that exception has occurred in the misjudged exhaust emission control catalyst that is set in the abnormity diagnosis of exhaust emission control catalyst.
The present invention is completed in view of the above subject, and its object is to inhibit in the output progress based on NOx sensor Misinterpretation occurs when the abnormity diagnosis of exhaust emission control catalyst.
The present invention is completed to solve the above problems, and main idea is as follows.
(1) a kind of emission-control equipment of internal combustion engine, has:
The exhaust channel in internal combustion engine, and catalyst-loaded noble metal is arranged in exhaust emission control catalyst;
NOx sensor, is arranged in the exhaust emission control catalyst or the flow direction of exhaust gases of the exhaust emission control catalyst The exhaust channel in downstream side;
The exhaust in the flow direction of exhaust gases downstream side of the exhaust emission control catalyst is arranged in air-fuel ratio sensor Access;With
Control device controls the target air-fuel ratio of the exhaust flowed into the exhaust emission control catalyst, and is based on institute Exporting to estimate the state of the exhaust emission control catalyst for NOx sensor is stated,
The target air-fuel ratio is alternately set as dense air-fuel ratio and Bi Li than richer by the control device Become than theory by dilute air-fuel ratio of air-fuel ratio, also, in the air-fuel ratio of the exhaust detected from the air-fuel ratio sensor When below the dense dense judgement air-fuel ratio of air-fuel ratio, the switching from dense air-fuel ratio to dilute air-fuel ratio of the target air-fuel ratio is carried out,
The control device executes the presumption control of the 1st degradation, in the 1st degradation presumption control, is not The output of NOx sensor when air-fuel ratio based on the exhaust flowed into the exhaust emission control catalyst is dilute air-fuel ratio, But the air-fuel ratio based on the exhaust flowed into the exhaust emission control catalyst be dense air-fuel ratio when the NOx sensor it is defeated Go out, come estimate with catalyst noble metal sintering the exhaust emission control catalyst the deterioration that can not restore degree.
(2) emission-control equipment of the internal combustion engine according to above-mentioned (1),
The control device carries out the exhaust emission control catalyst based on the degree of the deterioration that can not restore Abnormity diagnosis, also, carry out the row when the air-fuel ratio of the exhaust flowed into the exhaust emission control catalyst is dense air-fuel ratio The abnormity diagnosis of gas cleaning catalyst, and when the air-fuel ratio of the exhaust flowed into the exhaust emission control catalyst is dilute air-fuel ratio Abnormity diagnosis without the exhaust emission control catalyst.
(3) emission-control equipment of the internal combustion engine according to above-mentioned (1) or (2),
The control device, in the 1st degradation presumption control, based on being switched to from by the target air-fuel ratio The air-fuel ratio that dense air-fuel ratio plays the exhaust flowed into the exhaust emission control catalyst until being switched to dilute air-fuel ratio is The output of the NOx sensor during the center of switching timing in during dense air-fuel ratio, leaving target air-fuel ratio, Come estimate the exhaust emission control catalyst the deterioration that can not restore degree.
(4) according to the emission-control equipment of any one of them internal combustion engine of above-mentioned (1)~(3),
The control device executes the presumption control of the 2nd degradation not against the output of the NOx sensor, in institute It states in the presumption control of the 2nd degradation, presumption includes the sulphur of the deterioration and the exhaust emission control catalyst that can not restore Total degradation of the exhaust emission control catalyst of the caused deterioration that can restore of poisoning,
The control device based on the total degradation deduced by the 2nd degradation presumption controls and leads to The degree of the deterioration that can not restore crossed the 1st degradation presumption control and deduced, to estimate the exhaust gas purification The degree of the deterioration that can restore of catalyst.
(5) emission-control equipment of the internal combustion engine according to above-mentioned (3),
The control device executes the presumption control of the 2nd degradation not against the output of the NOx sensor, in institute It states in the presumption control of the 2nd degradation, presumption includes the sulphur of the deterioration and the exhaust emission control catalyst that can not restore Total degradation of the exhaust emission control catalyst of the caused deterioration that can restore of poisoning,
The control device can not restore bad based on what is deduced by the 1st degradation is estimated and controlled The degree of change sets poisoning a reference value so that and the degree of the deterioration that can not restore the big, a reference value of being poisoned is bigger, If the total degradation deduced by the 2nd degradation is estimated and controlled becomes the poisoning a reference value or more, It is determined as the exhaust emission control catalyst sulfur poisoning.
(6) emission-control equipment of the internal combustion engine according to above-mentioned (4) or (5),
It is also equipped with air-fuel ratio sensor, institute is set in the flow direction of exhaust gases downstream side of the exhaust emission control catalyst Exhaust channel is stated,
The control device, in the 2nd degradation presumption control, the output based on the air-fuel ratio sensor is empty It fires more empty than playing the dilute judgement for becoming diluter than chemically correct fuel from state more below than the dense judgement air-fuel ratio of richer Oxygen amount of the combustion than being absorbed by the exhaust emission control catalyst until above or the parameter value changed or institute corresponding to the oxygen amount Stating the state of the output air-fuel ratio of air-fuel ratio sensor more than dilute judgement air-fuel ratio and playing becomes dense judgement air-fuel ratio or less and is The oxygen amount only discharged from the exhaust emission control catalyst or the parameter value changed corresponding to the oxygen amount, it is net to estimate the exhaust Change total degradation of catalyst.
(7) emission-control equipment of the internal combustion engine according to above-mentioned (4) or (5),
It is also equipped with air-fuel ratio sensor, institute is set in the flow direction of exhaust gases downstream side of the exhaust emission control catalyst Exhaust channel is stated,
The control device becomes comparing chemically correct fuel in the air-fuel ratio of the exhaust detected from the air-fuel ratio sensor When below dense dense judgement air-fuel ratio, the switching from dense air-fuel ratio to dilute air-fuel ratio of the target air-fuel ratio is carried out,
The control device, in the 2nd degradation presumption control, based in the target air-fuel ratio from dense air-fuel Than the sky being switched to after dilute air-fuel ratio until the output air-fuel ratio of the air-fuel ratio sensor reaches chemically correct fuel At least part of behavior for firing the output air-fuel ratio than sensor, to estimate total deterioration journey of the exhaust emission control catalyst Degree.
(8) emission-control equipment of the internal combustion engine according to above-mentioned (4),
The control device executes containing ratio presumption control, in containing ratio presumption control, based on relative to the time Or the passage of the degree of the deterioration that can restore of the exhaust emission control catalyst of the variation of the accumulated value of inhaled air volume, come Estimate the sulphur containing ratio of the fuel supplied to the internal combustion engine.
(9) emission-control equipment of the internal combustion engine according to above-mentioned (8),
The control device executes the sulphur disengaging processing for making to be detached from by the sulphur ingredient that the exhaust emission control catalyst absorbs,
The containing ratio presumption control is detached from after treatment in the sulphur and starts.
In accordance with the invention it is possible to which providing can inhibit that cleaning catalyst is exhausted in the output based on NOx sensor The emission-control equipment of the internal combustion engine of misinterpretation occurs when abnormity diagnosis.
Description of the drawings
Fig. 1 is the figure for the internal combustion engine that outlined the emission-control equipment for having used an embodiment to be related to.
Fig. 2 is the relationship of the air-fuel ratio for indicating the exhaust around air-fuel ratio sensor and the output current of air-fuel ratio sensor Figure.
Fig. 3 is when indicating internal combustion engine operation, the sequential of the variation of the oxygen occlusion amount of upstream side exhaust emission control catalyst etc. Figure.
Fig. 4 is the flow chart for the control program for indicating the setting control of air-fuel ratio correction amount.
Fig. 5 is in the case of indicating target air-fuel ratio for dense air-fuel ratio, inhaled air volume and is detected by NOx sensor NOx concentration relationship figure.
Fig. 6 is in the case of indicating target air-fuel ratio for dilute air-fuel ratio, inhaled air volume and is detected by NOx sensor NOx concentration relationship figure.
Fig. 7 is upstream side exhaust emission control catalyst when indicating to carry out the abnormity diagnosis of upstream side exhaust emission control catalyst 20 The variation of 20 oxygen occlusion amount etc., same as Fig. 3 sequence diagram.
Fig. 8 is the control program for indicating to carry out the abnormality diagnostic abnormity diagnosis control of upstream side exhaust emission control catalyst Flow chart.
Fig. 9 is upstream side exhaust emission control catalyst when indicating to carry out the abnormity diagnosis of upstream side exhaust emission control catalyst The variation of oxygen occlusion amount etc., same as Fig. 7 sequence diagram.
Figure 10 is to indicate that the abnormality diagnostic exception of the present embodiment for carrying out upstream side exhaust emission control catalyst is examined The flow chart of the control program of disconnected control.
Figure 11 is upstream side exhaust emission control catalyst when indicating to carry out the abnormity diagnosis of upstream side exhaust emission control catalyst Oxygen occlusion amount etc. variation, same as Fig. 7 sequence diagram.
Figure 12 is in the case of indicating target air-fuel ratio for dense air-fuel ratio, inhaled air volume and is detected by NOx sensor The relationship of the NOx concentration gone out, similarly scheme with Fig. 5.
Figure 13 is the sectional view showed schematically near the surface of exhaust emission control catalyst.
Figure 14 is to indicate that inhaled air volume and the NOx concentration detected by NOx sensor are urged with upstream side exhaust gas purification The figure of the relationship of degradation caused by permanently deteriorating of agent.
Figure 15 is to indicate to carry out the presumption of degradation caused by permanently deteriorating of upstream side exhaust emission control catalyst The flow chart of the control program of degradation presumption control.
Figure 16 is in the case of having carried out air-fuel ratio control same as third embodiment shown in Figure 11, air-fuel ratio The sequence diagram of correction amount etc..
Figure 17 is to indicate inhaled air volume and can absorb oxygen amount with upstream side exhaust emission control catalyst by S poisoning deteriorations The figure of the relationship of caused degradation.
Figure 18 is to indicate inhaled air volume and can absorb oxygen amount with upstream side exhaust emission control catalyst by S poisoning deteriorations The figure of the relationship of caused degradation.
Figure 19 is to indicate that the S of degradation caused by S poisoning deteriorations of judgement upstream side exhaust emission control catalyst is poisoned Judge the flow chart of the control program of control.
Figure 20 is the sequence diagram of in the case of having carried out air-fuel ratio control, air-fuel ratio correction amount etc..
Figure 21 is indicated in the emission-control equipment that sixth embodiment is related to, and judges upstream side exhaust emission control catalyst By S poisoning deterioration caused by degradation S poisoning judgement control control program flow chart.
Figure 22 is the sequence diagram of degradation caused by S poisoning deteriorations of upstream side exhaust emission control catalyst.
Figure 23 is the S of degradation caused by S poisoning deteriorations indicated for calculating upstream side exhaust emission control catalyst Degradation of being poisoned calculates the flow chart of the control program of control.
Figure 24 is the sulphur ingredient containing ratio presumption control for indicating to estimate the sulphur ingredient containing ratio into the fuel that combustion chamber 5 supplies The flow chart of the control program of system.
Reference sign
1:Body of the internal-combustion engine
5:Combustion chamber
7:Air inlet
9:Exhaust outlet
19:Exhaust manifold
20:Upstream side exhaust emission control catalyst
24:Downstream side exhaust emission control catalyst
31:ECU
40:Upstream side air-fuel ratio sensor
41:Downstream side air-fuel ratio sensor
46:NOx sensor
Specific implementation mode
Hereinafter, with reference to attached drawing, detailed description of embodiments of the present invention.Furthermore in the following description, equally Inscape be attached to identical reference marker.
< first embodiments >
"The explanation of internal combustion engine totality"
Fig. 1 be outlined using the first embodiment of the present invention is related to emission-control equipment internal combustion engine Figure.Referring to Fig.1,1 body of the internal-combustion engine is indicated, 2 indicate cylinder block, and 3 indicate the piston to move back and forth in cylinder block 2,4 tables Show the cylinder head being fixed in cylinder block 2,5 indicate the combustion chamber being formed between piston 3 and cylinder head 4, and 6 indicate intake valves, 7 Indicate air inlet, 8 indicate air bleeding valve, and 9 indicate exhaust outlet.Air inlet 7 is opened and closed in intake valve 6, and air bleeding valve 8 is to exhaust outlet 9 It is opened and closed.
As shown in Figure 1, the central portion in the internal face of cylinder head 4 is configured with spark plug 10, in the internal face week of cylinder head 4 Edge is configured with fuel injection valve 11.Spark plug 10 is configured to generate spark according to ignition signal.In addition, fuel injection valve 11 spray the fuel of specified amount according to injection signal into combustion chamber 5.Furthermore fuel injection valve 11 can also be with to air inlet The mode of injection fuel configures in 7.In addition, in the present embodiment, as fuel, the vapour for the use of chemically correct fuel being 14.6 Oil.But using the present invention emission-control equipment internal combustion engine in, can also use gasoline other than fuel or with The fuel combination that gasoline mixes.
The air inlet 7 of each cylinder links via corresponding inlet manifold 13 and surge tank (surge tank) 14 respectively, delays Tank 14 is rushed via air inlet pipe 15 and air cleaner 16 to link.Air inlet 7, inlet manifold 13, surge tank 14, the formation of air inlet pipe 15 Intake channel.In addition, configured with the throttle valve 18 driven by throttle valve driving actuator 17 in air inlet pipe 15.Throttle valve 18 is logical It crosses and drives actuator 17 to make its rotation using throttle valve, the opening area of intake channel can be changed.
On the other hand, the exhaust outlet 9 of each cylinder links with exhaust manifold 19.Exhaust manifold 19 has to be connected with each exhaust outlet 9 Multiple branches of knot and the collection portion for having gathered these branches.The collection portion of exhaust manifold 19, with built-in upstream side row The upstream side shell (casing) 21 of gas cleaning catalyst 20 links.Upstream side shell 21 is via exhaust pipe 22 and built-in downstream The downstream side shell 23 of side exhaust emission control catalyst 24 links.Exhaust outlet 9, exhaust manifold 19, upstream side shell 21, exhaust pipe 22 And downstream side shell 23 forms exhaust channel.
Electronic control unit (ECU) 31 includes digital computer, has the RAM being connected with each other via bi-directional bus 32 (random access memory) 33, ROM (read-only memory) 34, CPU (microprocessor) 35, input port 36 and output port 37.Configured with the air flow meter 39 for detecting the air mass flow flowed in air inlet pipe 15, the air in air inlet pipe 15 The output of flowmeter 39 is input into input port 36 via corresponding AD converter 38.In addition, in the set of exhaust manifold 19 Portion is configured with the sky to the exhaust (that is, exhaust that exhaust emission control catalyst 20 flows into the upstream side) flowed in exhaust manifold 19 The upstream side air-fuel ratio sensor 40 that combustion ratio is detected.Moreover, configured with to the flowing in exhaust pipe 22 in exhaust pipe 22 Exhaust (that is, from upstream side exhaust emission control catalyst 20 flow out and downstream exhaust emission control catalyst 24 inflow exhaust) The downstream side air-fuel ratio sensor 41 that air-fuel ratio is detected.The output of these air-fuel ratio sensors 40,41 is also via corresponding AD converter 38 is input into input port 36.
In the present embodiment, as air-fuel ratio sensor 40,41, the air-fuel ratio sensor of operating limit current type.Cause This, air-fuel ratio sensor 40,41, as shown in Fig. 2, the air-fuel ratio for the exhaust being configured to around air-fuel ratio sensor 40,41 is got over High (i.e. diluter), the output current from air-fuel ratio sensor 40,41 are bigger.In particular, the air-fuel ratio of present embodiment passes Sensor 40,41 is configured to the air-fuel ratio relative to the exhaust around air-fuel ratio sensor 40,41, output current linearly (at Ratio) variation.Furthermore in the present embodiment, the air-fuel of carrying current formula has been used as air-fuel ratio sensor 40,41 It, then can also operating limit current type sky but if being to export the sensor changed according to the air-fuel ratio of exhaust than sensor Combustion is than the air-fuel ratio sensor other than sensor.As such air-fuel ratio sensor, such as it can enumerate and not sensed to constituting Apply voltage between the electrode of device and export lambda sensor jumpy near chemically correct fuel etc..
In turn, in the emission-control equipment of present embodiment, configured with to the stream in exhaust pipe 22 in exhaust pipe 22 The NOx sensor 46 that the NOx concentration of dynamic exhaust is detected.Therefore, the configuration of NOx sensor 46 in upstream side, urge by exhaust gas purification The flow direction of exhaust gases downstream side of agent 20, to from upstream side exhaust emission control catalyst 20 outflow and downstream exhaust gas purification urge The NOx concentration for the exhaust that agent 24 flows into is detected.NOx concentration that NOx sensor 46 is configured in exhaust is higher, and its is defeated Go out bigger.The output of NOx sensor 46 is input into input port 36 via corresponding AD converter 38.Furthermore NOx is sensed Device 46 can also be configured to:Be installed on upstream side body 21, to the NOx concentration in upstream side exhaust emission control catalyst 20 into Row detection.In addition, NOx sensor 46 can also be integrally formed with downstream side air-fuel ratio sensor 41.
In addition, being connected with the negative of the generation output voltage proportional to the amount of depressing of gas pedal 42 in gas pedal 42 The output voltage of lotus sensor 43, load sensor 43 is input into input port 36 via corresponding AD converter 38.Bent axle Rotary angle transmitter 44, such as bent axle often rotate 15 degree and just generate output pulse, which is input into input port 36. CPU35 calculates internal-combustion engine rotational speed according to the output pulse of the crank angle sensor 44.On the other hand, output port 37 via Corresponding driving circuit 45 is connect with spark plug 10, fuel injection valve 11 and throttle valve driving actuator 17.Furthermore ECU31 As the target air-fuel ratio of the control exhaust that exhaust emission control catalyst 20 flows into the upstream side, and based on NOx sensor 46 Output carries out the abnormality diagnostic control of upstream side exhaust emission control catalyst 20 and diagnostic device plays a role.
Upstream side exhaust emission control catalyst 20 and downstream side exhaust emission control catalyst 24 are the ternarys with oxygen occlusion capacity Catalyst.Specifically, exhaust emission control catalyst 20,24 is to make the supported carrier being made of ceramics urging with catalytic action Agent noble metal (such as platinum (Pt)) and substance (such as ceria (CeO with oxygen occlusion capacity2)) three-way catalyst. Three-way catalyst has following function:When the air-fuel ratio of the exhaust flowed into three-way catalyst is maintained at chemically correct fuel, Purify unburned HC, CO and NOx simultaneously.Moreover, having the case where oxygen to a certain degree in the occlusion of exhaust emission control catalyst 20,24 Under, though the air-fuel ratio of the exhaust flowed into exhaust emission control catalyst 20,24 relative to chemically correct fuel to dense side or dilute side It offsets by, unburned HC, CO and NOx are also purified simultaneously.
That is, if exhaust emission control catalyst 20,24 has oxygen occlusion capacity, that is, if exhaust emission control catalyst 20,24 Oxygen occlusion amount can absorb oxygen amount less than maximum, then become to compare in the air-fuel ratio of the exhaust flowed into exhaust emission control catalyst 20,24 Chemically correct fuel it is dilute some when, superfluous oxygen contained in exhaust can be sucked into exhaust emission control catalyst 20,24.Thus, It is maintained at chemically correct fuel on the surface of exhaust emission control catalyst 20,24.As a result, in exhaust emission control catalyst 20,24 On surface, unburned HC, CO and NOx are purified simultaneously, the air-fuel for the exhaust flowed out at this time from exhaust emission control catalyst 20,24 Than becoming chemically correct fuel.
On the other hand, if exhaust emission control catalyst 20,24 is in the state that can discharge oxygen, that is, if exhaust gas purification The oxygen occlusion amount of catalyst 20,24 is more than 0, then becomes to compare in the air-fuel ratio of the exhaust flowed into exhaust emission control catalyst 20,24 Richer some when, unburned HC, CO contained in exhaust can be made to restore institute from the release of exhaust emission control catalyst 20,24 Insufficient oxygen.Thus, in this case, chemically correct fuel is also maintained on the surface of exhaust emission control catalyst 20,24.It is tied Fruit, on the surface of exhaust emission control catalyst 20,24, unburned HC, CO and NOx are purified simultaneously, at this time from exhaust gas purification The air-fuel ratio for the exhaust that catalyst 20,24 flows out becomes chemically correct fuel.
In this way, in the case where the occlusion of exhaust emission control catalyst 20,24 has oxygen to a certain degree, even if being urged to exhaust gas purification The air-fuel ratio for the exhaust that agent 20,24 flows into is offset by relative to chemically correct fuel to dense side or dilute side, unburned HC, CO and NOx is also purified simultaneously, and the air-fuel ratio for the exhaust flowed out from exhaust emission control catalyst 20,24 becomes chemically correct fuel.
"Basic control"
Then, illustrate the general of the basic air-fuel ratio control in the emission-control equipment of internal combustion engine of the present embodiment It wants.In the air-fuel ratio control of present embodiment, following feedback controls are carried out:Output based on upstream side air-fuel ratio sensor 40 Air-fuel ratio, to control the fuel injection amount from fuel injection valve 11, so that the output of upstream side air-fuel ratio sensor 40 is empty Combustion ratio becomes target air-fuel ratio.That is, in the air-fuel ratio control of present embodiment, based on the defeated of upstream side air-fuel ratio sensor 40 Go out air-fuel ratio to carry out feedback control, so that the air-fuel ratio for the exhaust that exhaust emission control catalyst 20 flows into the upstream side becomes mesh Mark air-fuel ratio.Furthermore " output air-fuel ratio " refers to and the comparable air-fuel ratio of the output valve of air-fuel ratio sensor.
In addition, in the air-fuel ratio control of present embodiment, the output air-fuel ratio based on downstream side air-fuel ratio sensor 41 Etc. setting target air-fuel ratio.Specifically, when the output air-fuel ratio of downstream side air-fuel ratio sensor 41 becomes dense air-fuel ratio, Target air-fuel ratio is set to dilute setting air-fuel ratio.As a result, the sky for the exhaust that exhaust emission control catalyst 20 flows into the upstream side Combustion is than also becoming dilute setting air-fuel ratio.Here, dilute setting air-fuel ratio is than chemically correct fuel (air-fuel ratio for becoming control centre) The air-fuel ratio of dilute preset certain value to a certain degree, such as be set as 14.65~20, be preferably 14.65~18, more preferable It is 14.65~16 or so.In addition, dilute setting air-fuel ratio can also be expressed as the air-fuel ratio as control centre (in this embodiment party It is chemically correct fuel in formula) plus air-fuel ratio obtained from positive air-fuel ratio correction amount.Moreover, in the present embodiment, under The output air-fuel ratio of trip side air-fuel ratio sensor 41 become the dense judgement air-fuel ratio (such as 14.55) slightly denseer than chemically correct fuel with When lower, it is judged as that the output air-fuel ratio of downstream side air-fuel ratio sensor 41 becomes for dense air-fuel ratio.
If target air-fuel ratio is changed to dilute setting air-fuel ratio, exhaust emission control catalyst 20 to the upstream side is flowed into The oxygen excess of exhaust is in shortage to be accumulated.Oxygen excess is in shortage, it is intended that:To make the stream of exhaust emission control catalyst 20 to the upstream side The air-fuel ratio of the exhaust entered become when becoming chemically correct fuel superfluous oxygen amount or the amount of insufficient oxygen (superfluous is unburned HC, CO etc. (the hereinafter referred to as amount of " unburned gas ").Especially when target air-fuel ratio becomes for dilute setting air-fuel ratio, upwards Oxygen in the exhaust that trip side exhaust emission control catalyst 20 flows into becomes superfluous, and the oxygen of the surplus is by upstream side exhaust emission control catalyst 20 absorb.Therefore, it can be said that the insufficient amount of accumulated value of oxygen excess (hereinafter referred to as " accumulation oxygen excess is in shortage ") is upstream side row The presumed value of the oxygen occlusion amount OSA of gas cleaning catalyst 20.
Furthermore the insufficient amount of calculating of oxygen excess, based on according to the output air-fuel ratio of upstream side air-fuel ratio sensor 40 and The presumed value of the inhaled air volume into combustion chamber 5 of output of air flow meter 39 etc. and calculating comes from fuel injection valve 11 Fuel feed etc. carry out.Specifically, oxygen excess OED in shortage is for example calculated by following formula (1).
OED=0.23 × Qi × (AFup-AFR) ... (1)
Here, 0.23 indicates that the oxygen concentration in air, Qi indicate that fuel injection amount, AFup indicate upstream side air-fuel ratio sensing The output air-fuel ratio of device 40, AFR are expressed as air-fuel ratio (in the present embodiment, the substantially theoretical air-fuel at center in order to control Than).
If it is in shortage to the oxygen excess calculated in this way accumulate obtained from accumulation oxygen excess is in shortage becomes advance More than the switching a reference value (being equivalent to preset switching benchmark occlusion amount Cref) of setting, then will so far be dilute setting air-fuel The target air-fuel ratio of ratio is set as dense setting air-fuel ratio.Dense setting air-fuel ratio is (to become the sky of control centre than chemically correct fuel Fire ratio) dense preset air-fuel ratio to a certain degree, such as be set as 12~14.58, be preferably 13~14.57, more preferable It is 14~14.55 or so.In addition, dense setting air-fuel ratio can also be expressed as the air-fuel ratio as control centre (in this embodiment party It is chemically correct fuel in formula) plus air-fuel ratio obtained from negative air-fuel ratio correction amount.Furthermore it is in the present embodiment, dense to set Determine air-fuel ratio and chemically correct fuel difference (dense degree) be set as the difference (dilute degree) of dilute setting air-fuel ratio and chemically correct fuel with Under.
Thereafter, when the output air-fuel ratio of downstream side air-fuel ratio sensor 41 becomes dense judgement air-fuel ratio or less again, mesh Mark air-fuel ratio is set as dilute setting air-fuel ratio again, thereafter, same operation is repeated.In this way, in the present embodiment, to Upstream side exhaust emission control catalyst 20 flow into exhaust target air-fuel ratio be alternately set as repeatedly dilute setting air-fuel ratio with Dense setting air-fuel ratio.In other words, in the present embodiment, it may be said that the exhaust that exhaust emission control catalyst 20 flows into the upstream side Air-fuel ratio be alternately set as dense air-fuel ratio and dilute air-fuel ratio.
"The explanation for having used the air-fuel ratio of sequence diagram to control"
With reference to Fig. 3, operation as described above is specifically described.Fig. 3 is the air-fuel ratio control for having carried out present embodiment In the case of, the output air-fuel ratio AFup of air-fuel ratio correction amount, upstream side air-fuel ratio sensor 40, upstream side exhaust gas purification urge The oxygen occlusion amount OSA of agent 20, the output air-fuel of accumulation oxygen excess Σ OED in shortage and downstream side air-fuel ratio sensor 41 Sequence diagram than AFdwn.
Furthermore air-fuel ratio correction amount AFC is the target empty of the exhaust flowed into about exhaust emission control catalyst 20 to the upstream side Fire the correction amount of ratio.Air-fuel ratio correction amount AFC be 0 when, target air-fuel ratio be set as with as control centre air-fuel ratio (with Under, referred to as " control centre's air-fuel ratio ") equal air-fuel ratio (being in the present embodiment chemically correct fuel), in air-fuel ratio correction When amount AFC is positive value, target air-fuel ratio becomes than the air-fuel ratio of control centre air-fuel ratio (being in the present embodiment dilute air-fuel Than), when air-fuel ratio correction amount AFC is negative value, target air-fuel ratio becomes the air-fuel ratio denseer than control centre air-fuel ratio (in this reality It is dense air-fuel ratio to apply in mode).In addition, " control centre's air-fuel ratio " means:Sky is added as according to internal combustion engine operation state The air-fuel ratio of the object than correction amount AFC is fired, i.e., base is being become according to air-fuel ratio correction amount AFC when target air-fuel ratio being made to change Accurate air-fuel ratio.
In the example in the figures, in moment t1Pervious state, air-fuel ratio correction amount AFC are set as dense setting correction amount AFCrich (corresponds to dense setting air-fuel ratio).That is, target air-fuel ratio is set as dense air-fuel ratio, along with this, upstream side air-fuel ratio The output air-fuel ratio of sensor 40 becomes dense air-fuel ratio.Contained in the exhaust that exhaust emission control catalyst 20 flows into the upstream side not Burning gases etc. are cleaned in upstream side exhaust emission control catalyst 20, and therewith, the oxygen of upstream side exhaust emission control catalyst 20 is inhaled Reserve OSA is gradually decreased down.By the purification in upstream side exhaust emission control catalyst 20, it is catalyzed from upstream side exhaust gas purification Without unburned gas etc. in the exhaust that agent 20 is flowed out, therefore the output air-fuel ratio AFdwn of downstream side air-fuel ratio sensor 41 is big Mutagens are chemically correct fuel.Since the air-fuel ratio for the exhaust that exhaust emission control catalyst 20 flows into the upstream side becomes for dense air-fuel Than so the NOx discharge rates from upstream side exhaust emission control catalyst 20 are few.
When the oxygen occlusion amount OSA of upstream side exhaust emission control catalyst 20 is progressively decreased, oxygen occlusion amount OSA connects to zero Closely, therewith, the part for flowing into unburned gas of upstream side exhaust emission control catalyst 20 etc. is not net in upstream side exhaust Change to be cleaned in catalyst 20 and begins to flow out.The output air-fuel ratio AFdwn of downstream side air-fuel ratio sensor 41 is gradually as a result, It reduces, in moment t1Under, the output air-fuel ratio AFdwn of downstream side air-fuel ratio sensor 41 reaches dense judgement air-fuel ratio AFrich.
In the present embodiment, when the output air-fuel ratio AFdwn of downstream side air-fuel ratio sensor 41 becomes dense judgement air-fuel When than AFrich or less, in order to make oxygen occlusion amount OSA increase, air-fuel ratio correction amount AFC is switched to dilute setting correction amount AFClean (corresponds to dilute setting air-fuel ratio).In addition, (reset) is 0 at this point, accumulation oxygen excess Σ OED in shortage are reset.
Furthermore in the present embodiment, it is empty to reach dense judgement by the output air-fuel ratio AFdwn of downstream side air-fuel ratio sensor 41 After combustion is than AFrich, the switching of air-fuel ratio correction amount AFC has been carried out.The reason is that even if upstream side exhaust emission control catalyst 20 Oxygen occlusion amount it is abundant, also minutely deviate reason from the air-fuel ratio pole of exhaust that upstream side exhaust emission control catalyst 20 flows out sometimes By air-fuel ratio.Dense judgement air-fuel ratio is configured such that the oxygen occlusion amount in upstream side exhaust emission control catalyst 20 is filled conversely speaking, The air-fuel ratio that the air-fuel ratio for the exhaust that timesharing is flowed out from upstream side exhaust emission control catalyst 20 will not reach.
In moment t1Under, when target air-fuel ratio is switched to dilute air-fuel ratio, exhaust emission control catalyst 20 flows into the upstream side Exhaust air-fuel ratio from dense air-fuel ratio variation be dilute air-fuel ratio.When in moment t1Under to the upstream side exhaust emission control catalyst 20 flow When the air-fuel ratio variation of the exhaust entered is dilute air-fuel ratio, then the oxygen occlusion amount OSA of upstream side exhaust emission control catalyst 20 increases.Separately Outside, therewith, accumulation oxygen excess Σ OED in shortage also gradually increase.
The air-fuel ratio variation for the exhaust flowed out as a result, from upstream side exhaust emission control catalyst 20 is chemically correct fuel, downstream The output air-fuel ratio AFdwn of side air-fuel ratio sensor 41 also converges on chemically correct fuel.At this point, exhaust gas purification is catalyzed to the upstream side The air-fuel ratio for the exhaust that agent 20 flows into becomes for dilute air-fuel ratio, but due to the oxygen occlusion capacity of upstream side exhaust emission control catalyst 20 Have and adequately have more than needed, so the oxygen in the exhaust flowed into is absorbed by upstream side exhaust emission control catalyst 20, NOx is reduced purification. Thus, the NOx discharge rates from upstream side exhaust emission control catalyst 20 are few.
Thereafter, when the oxygen occlusion amount OSA of the exhaust emission control catalyst of upstream side 20 increases, in moment t2Under, upstream side The oxygen occlusion amount OSA of exhaust emission control catalyst 20 reaches switching benchmark occlusion amount Cref.Thus, accumulation oxygen excess Σ in shortage OED is reached and the comparable switching a reference value OEDref of switching benchmark occlusion amount Cref.In the present embodiment, when accumulation oxygen excess When Σ OED in shortage become switching a reference value OEDref or more, for the suction of middle block exhaust emission control catalyst 20 to the upstream side It hides, air-fuel ratio correction amount AFC is switched to dense setting correction amount AFCrich.Therefore, target air-fuel ratio is set as dense air-fuel ratio. In addition, at this point, accumulation oxygen excess Σ OED in shortage are reset to 0.
Furthermore switch benchmark occlusion amount Cref to be set as fully less so that even if occurring to be caused by the unexpected acceleration of vehicle Unintentionally air-fuel ratio offset etc., oxygen occlusion amount OSA can absorb the amount of oxygen amount Cmax also less than up to maximum.For example, switching base Quasi- occlusion amount Cref be set as when upstream side exhaust emission control catalyst 20 is not used maximum can absorb the 3/4 of oxygen amount Cmax with Under, preferably 1/2 hereinafter, more preferably 1/5 or less.As a result, in the output air-fuel ratio of downstream side air-fuel ratio sensor 41 The AFdwn arrival dilute judgement air-fuel ratio slightly diluter than chemically correct fuel (such as 14.65.And the deviation of chemically correct fuel and dense judgement Dilute air-fuel ratio of air-fuel ratio and the identical degree of the difference of chemically correct fuel) before, air-fuel ratio correction amount AFC is switched to dense setting Correction amount AFCrich.
When in moment t2Lower when target air-fuel ratio is switched to dense air-fuel ratio, exhaust emission control catalyst 20 flows into the upstream side Exhaust air-fuel ratio from dilute air-fuel ratio variation be dense air-fuel ratio.Due to the row flowed into exhaust emission control catalyst 20 to the upstream side Comprising unburned gas etc. in gas, so the oxygen occlusion amount OSA of upstream side exhaust emission control catalyst 20 is gradually decreased down.At this time The NOx discharge rates from upstream side exhaust emission control catalyst 20 it is few.
When the oxygen occlusion amount OSA of upstream side exhaust emission control catalyst 20 is gradually decreased down, in moment t3Under, with the moment t1Similarly, the output air-fuel ratio AFdwn of downstream side air-fuel ratio sensor 41 reaches dense judgement air-fuel ratio AFrich.It is empty as a result, Combustion is switched to dilute setting correction amount AFClean than correction amount AFC.Then, t at the time of being repeated above-mentioned1~t3Cycle.
It from the above description, according to the present embodiment, can be by the NOx from upstream side exhaust emission control catalyst 20 Discharge rate is always suppressed to less.In addition, it is short during accumulation when due to calculating accumulation oxygen excess Σ OED in shortage, so with The case where being accumulated during length is compared, and calculating error is not likely to produce.Thus, it is possible to inhibit since accumulation oxygen excess is insufficient The case where measuring the calculating error of Σ OED and leading to that NOx is discharged.
In addition, usually, if the oxygen occlusion amount of exhaust emission control catalyst is maintained centainly, exhaust gas purification catalysis The oxygen occlusion capacity of agent reduces.That is, in order to maintain high the oxygen occlusion capacity of exhaust emission control catalyst, exhaust gas purification is needed to urge The oxygen occlusion amount of agent changes.In this regard, according to the present embodiment, as shown in figure 3, the oxygen of upstream side exhaust emission control catalyst 20 is inhaled Reserve OSA always changes up and down, therefore can inhibit the phenomenon that the reduction of oxygen occlusion capacity.
Furthermore in the above-described embodiment, in moment t1~t2, air-fuel ratio correction amount AFC is maintained at dilute setting correction amount AFClean.But in such period, air-fuel ratio correction amount AFC is not necessarily required to be maintained certain, can also be so that it is gradual The mode that is changed such as reduce to set in ground.Similarly, in the above-described embodiment, in moment t2~t3, air-fuel ratio correction amount AFC is maintained at dense setting correction amount AFCrich.But in such period, air-fuel ratio correction amount AFC is not necessarily required to maintain To be certain, can also by make its gradually increase etc. changed in a manner of set.
Furthermore the setting of the setting of the air-fuel ratio correction amount AFC in such present embodiment, i.e. target air-fuel ratio, by ECU31 is carried out.Therefore, ECU31 becomes in the air-fuel ratio of the exhaust detected by downstream side air-fuel ratio sensor 41 for dense judgement When below air-fuel ratio, the target air-fuel ratio for the exhaust that exhaust emission control catalyst 20 flows into the upstream side is set as dilute air-fuel ratio, Until oxygen occlusion amount OSA until being estimated as upstream side exhaust emission control catalyst 20 becomes switching benchmark occlusion amount Cref or more. Moreover, ECU31 the oxygen occlusion amount OSA for being estimated as upstream side exhaust emission control catalyst 20 become switch benchmark occlusion amount Cref with When upper, oxygen amount Cmax can be absorbed and target air-fuel ratio is set as dense air-fuel ratio by so that oxygen occlusion amount OSA is reached maximum, Zhi Daoyou Until the air-fuel ratio for the exhaust that downstream side air-fuel ratio sensor 41 detects becomes dense judgement air-fuel ratio or less.
More simply, in the present embodiment, it may be said that ECU31 is detected by downstream side air-fuel ratio sensor 41 Air-fuel ratio when becoming dense judgement air-fuel ratio or less, by target air-fuel ratio, (i.e. exhaust emission control catalyst 20 flows into the upstream side The air-fuel ratio of exhaust) it is switched to dilute air-fuel ratio, also, become cutting in the oxygen occlusion amount OSA of upstream side exhaust emission control catalyst 20 When changing benchmark occlusion amount Cref or more, by target air-fuel ratio (that is, the sky for the exhaust that exhaust emission control catalyst 20 flows into the upstream side Combustion ratio) it is switched to dense air-fuel ratio.
"The flow chart of air-fuel ratio correction amount setting control"
Fig. 4 is the flow chart for the control program for indicating the setting control of air-fuel ratio correction amount.The control program of diagram is with certain Time interval (for example, several milliseconds) executes.
As shown in figure 4, first, in step s 11, whether the design conditions of judgement air-fuel ratio correction amount AFC are true.Air-fuel The case where design conditions than correction amount AFC are set up, can enumerate:To carry out the usual control period of feedback control;Such as it is not Fuel cut-off control period etc.;Etc..In the case of being determined as that the design conditions of target air-fuel ratio are set up in step s 11, into Enter to step S12.
In step s 12, judge whether dilute setting mark Fl is configured to as OFF.When air-fuel ratio correction amount AFC is set When as dilute setting correction amount AFClean, dilute setting mark Fl is set as ON, and OFF is set as other than it.In step In rapid S12, in the case that dilute setting mark Fl has been configured to as OFF, step S13 is entered.In step s 13, under judgement Whether the output air-fuel ratio AFdwn for swimming side air-fuel ratio sensor 41 is dense judgement air-fuel ratio AFrich or less.It is being determined as downstream In the case that the output air-fuel ratio AFdwn of side air-fuel ratio sensor 41 is more than dense judgement air-fuel ratio AFrich, step is entered S14.In step S14, air-fuel ratio correction amount AFC is maintained to be set to the state of dense setting correction amount AFCrich, finishing control Program.
On the other hand, when the oxygen occlusion amount OSA reductions of upstream side exhaust emission control catalyst 20, to net from upstream side exhaust When changing the air-fuel ratio decline for the exhaust that catalyst 20 flows out, it is determined as the defeated of downstream side air-fuel ratio sensor 41 in step s 13 It is dense judgement air-fuel ratio AFrich or less to go out air-fuel ratio AFdwn.In this case, step S15 is entered, by air-fuel ratio correction amount AFC is switched to dilute setting correction amount AFClean.Then, in step s 16, dilute setting mark Fl is set to ON, finishing control Program.
When dilute setting mark Fl is set to ON, in next control program, it is determined as dilute set in step s 12 Calibration will Fl is not set to OFF, enters step S17.In step S17, determine whether from air-fuel ratio correction amount AFC quilts It is switched to the accumulation oxygen excess Σ OED in shortage that dilute setting correction amount AFClean is started and is less than switching a reference value OEDref.Sentencing In the case of being set to accumulation oxygen excess Σ OED in shortage less than switching a reference value OEDref, step S18 is entered, air-fuel is maintained Continue the state for being set as dilute setting correction amount AFClean, finishing control program than correction amount AFC.On the other hand, work as upstream side When the oxygen occlusion amount of exhaust emission control catalyst 20 increases, it is determined as that accumulating oxygen excess Σ OED in shortage is in step S17 soon Switch a reference value OEDref or more, enters step S19.In step S19, air-fuel ratio correction amount AFC is switched to dense setting Correction amount AFCrich.Then, in step S20, dilute setting mark Fl is reset to OFF, finishing control program.
"The degradation of catalyst"
The exhaust emission control catalyst 20,24 constituted as described above, when chronically use exhaust emission control catalyst 20,24, Or exhaust emission control catalyst 20,24 chronically exposure at high temperature when, can deteriorate significantly.Specifically, being catalyzed in exhaust gas purification The catalyst noble metal supported with finely particulate dispersion on the carrier of agent 20,24 is combined due to sintering, and catalytic activity reduces.
If its activity is reduced due to the sintering of catalyst noble metal in this wise, even if around catalyst noble metal There are unburned HC, oxygen, NOx, also become unable to that these ingredients is enough made fully to react.That is, working as exhaust emission control catalyst 20,24 When deteriorating significantly, reduced to being flowed into the detergent power of exhaust of exhaust emission control catalyst 20,24.
Here, since upstream side exhaust emission control catalyst 20 as described above has oxygen occlusion capacity, so whether mesh When mark air-fuel ratio is set as dense air-fuel ratio or when target air-fuel ratio is set as dilute air-fuel ratio, it can inhibit to come from upstream side The NOx discharge rates of exhaust emission control catalyst 20.
That is, it is set as dense air-fuel ratio in target air-fuel ratio, the sky for the exhaust that exhaust emission control catalyst 20 flows into the upstream side When combustion is than becoming dense air-fuel ratio, from the exhaust that body of the internal-combustion engine 1 be discharged containing a large amount of unburned HC, CO and on a small quantity NOx and oxygen.Thus, the work that the NOx in the exhaust that exhaust emission control catalyst 20 flows into the upstream side passes through catalyst noble metal It reacts to be reduced, purify with and with these unburned HC, CO.As a result, it is possible to will be from upstream side exhaust emission control catalyst NOx concentration in the exhaust of 20 outflows is maintained very low.
On the other hand, it is set as dilute air-fuel ratio in target air-fuel ratio, the row that exhaust emission control catalyst 20 flows into the upstream side When the air-fuel ratio of gas becomes dilute air-fuel ratio, a large amount of oxygen and NOx and a small amount of are being contained from the exhaust that body of the internal-combustion engine 1 is discharged Unburned HC, CO.When exhaust emission control catalyst 20 flows into the exhaust containing a large amount of oxygen and NOx to the upstream side, in exhaust Oxygen absorbed by upstream side exhaust emission control catalyst 20.As a result, remaining NOx in exhaust, remaining NOx is by urging in exhaust The effect of agent noble metal and react to be reduced with unburned HC, CO contained in exhaust, purify.As a result, it is possible to will It is maintained very low from the NOx concentration in the exhaust that upstream side exhaust emission control catalyst 20 flows out.
However, when upstream side exhaust emission control catalyst 20 deteriorates, that is, when its activity is due to catalyst noble metal When being sintered and reducing, upstream side exhaust emission control catalyst 20 becomes unable to make unburned HC, CO and NOx in the exhaust of inflow Fully react.As a result, when upstream side exhaust emission control catalyst 20 deteriorates, even upstream side exhaust gas purification is catalyzed When absorbing aerobic in agent 20, if target air-fuel ratio is set to dense air-fuel ratio so that exhaust emission control catalyst 20 flows to the upstream side The air-fuel ratio of the exhaust entered becomes dense air-fuel ratio, then also can flow out NOx from upstream side exhaust emission control catalyst 20.Similarly, i.e., Enable to be state that upstream side exhaust emission control catalyst 20 absorbs oxygen, if target air-fuel ratio be set to dilute air-fuel ratio to Exhaust emission control catalyst 20, which flows into the air-fuel ratio being vented, to the upstream side becomes dilute air-fuel ratio, then can also be urged from upstream side exhaust gas purification Agent 20 flows out NOx.
The target air-fuel ratio for the exhaust that exhaust emission control catalyst 20 flows into the upstream side is being set as dense sky conversely speaking, Fire ratio, and the oxygen occlusion amount OSA of upstream side exhaust emission control catalyst 20 do not become zero nearby when (that is, being arranged by upstream side The air-fuel ratio of the oxygen occlusion capacity of gas cleaning catalyst 20, the exhaust flowed out from upstream side exhaust emission control catalyst 20 becomes theoretical When near air-fuel ratio), in the case of more than the NOx amount flowed out from upstream side exhaust emission control catalyst 20, it can be judged as upstream Side exhaust emission control catalyst 20 deteriorates significantly.Similarly, by the mesh for the exhaust that exhaust emission control catalyst 20 flows into the upstream side Mark air-fuel ratio set is dilute air-fuel ratio, and do not become maximum can by the oxygen occlusion amount OSA of upstream side exhaust emission control catalyst 20 (that is, by the oxygen occlusion capacity of upstream side exhaust emission control catalyst 20, from upstream side exhaust gas purification when absorbing near oxygen amount Cmax When the air-fuel ratio for the exhaust that catalyst 20 flows out becomes near chemically correct fuel), it is flowed from upstream side exhaust emission control catalyst 20 In the case of more than the NOx amount gone out, it can be judged as that upstream side exhaust emission control catalyst 20 deteriorates significantly.
"The relationship of dense weak point and degradation"
As described above, in the present embodiment, in the state that target air-fuel ratio is set as dense air-fuel ratio, downstream When the output air-fuel ratio AFdwn of side air-fuel ratio sensor 41 becomes dense judgement air-fuel ratio or less, by target air-fuel ratio from dense air-fuel Than being switched to dilute air-fuel ratio (t at the time of Fig. 31,t3).Therefore, target air-fuel ratio is being switched from dense air-fuel ratio to dilute air-fuel ratio When, the oxygen occlusion amount OSA of upstream side exhaust emission control catalyst 20 substantially becomes zero.Moreover, by target air-fuel ratio from dense air-fuel ratio After switching to dilute air-fuel ratio, until practically exhaust emission control catalyst 20 flows into the exhaust of dilute air-fuel ratio to the upstream side, need Time that will be to a certain degree.Therefore, it is being arranged to the upstream side from target air-fuel ratio is switched to dilute air-fuel ratio from dense air-fuel ratio playing During until the exhaust that gas cleaning catalyst 20 flows into dilute air-fuel ratio, the oxygen occlusion amount of exhaust emission control catalyst 20 in upstream side In the state that OSA is essentially a zero, temporarily exhaust gas purification is catalyzed to the upstream side for the exhaust of the dense air-fuel ratio containing unburned HC, CO Agent 20 flows into.
In this wise in the state that the oxygen occlusion amount OSA of upstream side exhaust emission control catalyst 20 is essentially a zero, dense air-fuel The exhaust of ratio temporarily to the upstream side exhaust emission control catalyst 20 flow into when, can upstream side exhaust emission control catalyst 20 catalysis Adhere to unburned HC, CO on agent noble metal.When adhering to unburned HC, CO on catalyst noble metal, it is capable of providing catalysis and makees The surface area of catalyst noble metal is reduced, and as a result causes the reduction of the catalytic action of catalyst noble metal (hereinafter, will in this way The phenomenon that be known as " HC poisonings ").Therefore, from by target air-fuel ratio from dense air-fuel ratio be switched to dilute air-fuel compared with to a certain degree Time becomes the state that the catalytic action of catalyst noble metal reduces.
Unburned HC, CO being attached on the surface of catalyst noble metal, thereafter when exhaust emission control catalyst to the upstream side 20 when being continuously flowed the exhaust of dilute air-fuel ratio, reacts with the oxygen in exhaust, to gradually de- from catalyst noble metal From.As such unburned HC, CO are detached from from catalyst noble metal, the catalytic action of catalyst noble metal also restores, therefore HC poisonings are eliminated.
However, due to when HC poisonings as described above occur, the catalytic action of catalyst noble metal reduces, so to the greatest extent Pipe upstream side exhaust emission control catalyst 20 does not deteriorate significantly, but the NOx amount flowed out from upstream side exhaust emission control catalyst 20 Become more.Therefore, net according to the NOx amount flowed out from upstream side exhaust emission control catalyst 20 progress upstream side exhaust as described above In the case of the abnormity diagnosis for changing catalyst 20, it is possible to be determined as that big deterioration has occurred in upstream side exhaust emission control catalyst.
Fig. 5 is to indicate the case where target air-fuel ratio is dense air-fuel ratio (for example, t at the time of in Fig. 32~t3) under, sucking it is empty The figure of the relationship of tolerance and the NOx concentration detected by NOx sensor 46.Square marks in Fig. 5 indicate that upstream side exhaust is net The relationship of (catalyst for not being deteriorated to the degree that detergent power substantially reduces) in the case of changing catalyst 20 normally, circle mark Note indicate 20 exception of upstream side exhaust emission control catalyst in the case of (be deteriorated to the degree that detergent power substantially reduces, it is so-called Standard (criteria) catalyst) relationship.
As can be seen from Figure 5, in the case where target air-fuel ratio is dense air-fuel ratio, that is, exhaust emission control catalyst 20 to the upstream side In the case that the air-fuel ratio of the exhaust of inflow is dense air-fuel ratio, regardless of inhaled air volume, upstream side exhaust emission control catalyst When 20 exception, compared with when upstream side exhaust emission control catalyst 20 is normal, the NOx detection limits detected by NOx sensor 46 are more. This is because as described above when upstream side exhaust emission control catalyst 20 is greatly deteriorated from upstream side exhaust emission control catalyst The NOx amount of 20 outflows increases caused.Furthermore in upstream side in the case of 20 exception of exhaust emission control catalyst, air is sucked Amount more increases, and the NOx concentration detected by NOx sensor 46 more increases, this is because with the increase of inhaled air volume, per single The NOx that the position time flows out from upstream side exhaust emission control catalyst 20 increases caused.On the other hand, in upstream side exhaust gas purification In the case of catalyst 20 is normal, even if inhaled air volume increases, since NOx is net in upstream side exhaust emission control catalyst 20 Change, therefore the NOx concentration detected by NOx sensor 46 is also maintained to be very low.
On the other hand, Fig. 6 is indicated the case where target air-fuel ratio is dilute air-fuel ratio (for example, t at the time of in Fig. 31~t2) Under inhaled air volume and the NOx concentration detected by NOx sensor 46 relationship figure.Square marks in Fig. 6 indicate Relationship in the case of swimming side exhaust emission control catalyst 20 normally, circular mark indicate that upstream side exhaust emission control catalyst 20 is abnormal In the case of relationship.It shows in the state that target air-fuel ratio is set as dense air-fuel ratio, downstream side air-fuel ratio sensor 41 Become dense judgement air-fuel ratio hereinafter, being passed to inhaled air volume target air-fuel ratio being switched to after dilute air-fuel ratio and by NOx The relationship for the NOx concentration that sensor 46 detects.
As can be seen from Figure 6, in the case where target air-fuel ratio is dilute air-fuel ratio, that is, exhaust emission control catalyst 20 to the upstream side In the case that the air-fuel ratio of the exhaust of inflow is dilute air-fuel ratio, if inhaled air volume is few, upstream side exhaust emission control catalyst 20 it is abnormal when with it is normal when compare, the NOx detection limits detected by NOx sensor 46 have almost no change.This is because as above-mentioned Even if target air-fuel ratio is being switching to dilute air-fuel ratio by such upstream side exhaust emission control catalyst 20 if deterioration greatly Time point upstream side exhaust emission control catalyst 20 have occurred HC poisoning caused by.Therefore, when target air-fuel ratio be dilute sky In the case of combustion ratio, the different of upstream side exhaust emission control catalyst 20 is carried out based on the NOx concentration detected by NOx sensor 46 Often when diagnosis, even if upstream side exhaust emission control catalyst 20 can be determined as that upstream side exhaust gas purification is urged if deterioration significantly Agent 20 exists abnormal.
On the other hand, as can be seen from Figure 6, in the case where target air-fuel ratio is dense air-fuel ratio, when inhaled air volume is more, on When swimming 20 exception of side exhaust emission control catalyst, compared with when its is normal, the NOx detection limits detected by NOx sensor 46 are also more. It is considered that this is because when inhaled air volume is more, the oxygen amount that exhaust emission control catalyst 20 flows into the upstream side is also more, knot Fruit, HC poisonings are early eliminated.Therefore, even the case where target air-fuel ratio is dense air-fuel ratio, if inhaled air volume is more, Then also it can suitably carry out upstream side exhaust emission control catalyst 20 based on the NOx concentration detected by NOx sensor 46 Abnormity diagnosis.
"The control that first embodiment is related to"
In the present embodiment, it is urged based on the NOx concentration detected by NOx sensor 46 to carry out upstream side exhaust gas purification The abnormity diagnosis of agent 20.In particular, being pre- in the NOx concentration Cnox detected by NOx sensor 46 in the present embodiment In the case of the determinating reference value Cnoxref or more first set, it is determined as the upstream side of the sintering along with catalyst noble metal Deterioration (the deterioration that can not restore of upstream side exhaust emission control catalyst 20 of exhaust emission control catalyst 20.Hereinafter also referred to as " permanent deterioration ") degree is high, and exception has occurred in upstream side exhaust emission control catalyst 20.Moreover, in the present embodiment, upward The air-fuel ratio for swimming the exhaust that side exhaust emission control catalyst 20 flows into is dense air-fuel ratio, is flowed out from upstream side exhaust emission control catalyst 20 Exhaust air-fuel ratio be chemically correct fuel when, carry out upstream side exhaust emission control catalyst 20 abnormity diagnosis, to the upstream side When the air-fuel ratio for the exhaust that exhaust emission control catalyst 20 flows into is dilute air-fuel ratio, without upstream side exhaust emission control catalyst 20 Abnormity diagnosis.In other words, it may be said that in the present embodiment, be not based on the row that exhaust emission control catalyst 20 flows into the upstream side The output of NOx sensor 46 when the air-fuel ratio of gas is dilute air-fuel ratio, but flowed based on exhaust emission control catalyst 20 to the upstream side Thus the output of NOx sensor 46 when the air-fuel ratio of the exhaust entered is dense air-fuel ratio carries out to estimate the degree permanently deteriorated The abnormity diagnosis of upstream side exhaust emission control catalyst 20.
Fig. 7 is upstream side exhaust emission control catalyst when indicating to carry out the abnormity diagnosis of upstream side exhaust emission control catalyst 20 The variation of 20 oxygen occlusion amount etc., same as 3 sequence diagram.It is dense especially with regard to the NOx detected by NOx sensor 46 It spends, the solid line in figure indicates that the normal situation of upstream side exhaust emission control catalyst 20, the dotted line in figure indicate that upstream side exhaust is net Change the abnormal situation of catalyst 20.Moreover, Fig. 7 shows NOx concentration in the case that inhaled air volume is less etc..Such as Fig. 7 institutes Show, when carrying out the abnormity diagnosis of upstream side exhaust emission control catalyst 20, also carries out air-fuel ratio control same as Fig. 3.
As shown in phantom in Figure 7, (the void in figure in the case where exception has occurred in upstream side exhaust emission control catalyst 20 Line), whether target air-fuel ratio is dense air-fuel ratio (when air-fuel ratio correction amount AFC is negative value) or target air-fuel ratio is dilute sky Combustion than when positive value (air-fuel ratio correction amount AFC be), the NOx concentration detected from NOx sensor 46 all becomes determinating reference value Cnoxref or more.
On the other hand, as shown in solid in Fig. 7, in upstream side, exhaust emission control catalyst 20 is normal (in figure Solid line), when target air-fuel ratio is dense air-fuel ratio (when air-fuel ratio correction amount AFC is negative value), detected by NOx sensor 46 NOx concentration becomes smaller than the low value of determinating reference value Cnoxref.In contrast, due to the influence that above-mentioned HC is poisoned, in mesh It marks when air-fuel ratio is dilute air-fuel ratio (when air-fuel ratio correction amount AFC is positive value), is become by the NOx concentration that NOx sensor 46 detects For the high value of determinating reference value Cnoxref or more.
Moreover, as described above, in the present embodiment, in the exhaust that exhaust emission control catalyst 20 to the upstream side flows into Air-fuel ratio be dense air-fuel ratio when, the X only in figure1Shown in during in, carry out upstream side exhaust emission control catalyst 20 it is different Often diagnosis.As can be seen from Figure 7, in figure X during1, in the case that in upstream side, exception has occurred in exhaust emission control catalyst 20, by The NOx concentration that NOx sensor 46 detects becomes determinating reference value Cnoxref or more.On the other hand, in this period X1, upper In the case of swimming side exhaust emission control catalyst 20 normally, the NOx concentration detected by NOx sensor 46 becomes smaller than determinating reference Value Cnoxref.Therefore, by this period X1Whether it is determinating reference value based on the NOx concentration detected by NOx sensor 46 Cnoxref or more carries out the abnormity diagnosis of upstream side exhaust emission control catalyst 20, so as to accurately judge that upstream side is arranged The exception of gas cleaning catalyst 20.
Furthermore in the above-described embodiment, independently with intake air amount, when target air-fuel ratio is dilute air-fuel ratio, no Carry out the abnormity diagnosis of upstream side exhaust emission control catalyst 20.But from Fig. 5 and Fig. 6 it is found that even if target air-fuel ratio is dilute sky Combustion ratio also can accurately be diagnosed if inhaled air volume is more based on the NOx concentration detected by NOx sensor 46 Swim the exception of side exhaust emission control catalyst 20.Therefore, even if target air-fuel ratio is dilute air-fuel ratio, in the combustion chamber 5 to internal combustion engine In the case that interior inhaled air volume is preset defined air capacity (such as 15g/ seconds) or more, upstream can also be carried out The abnormity diagnosis of side exhaust emission control catalyst 20.
"The explanation of flow chart"
Fig. 8 is the control program for indicating to carry out the abnormality diagnostic abnormity diagnosis control of upstream side exhaust emission control catalyst 20 Flow chart.The control program of diagram is spaced execution at regular intervals.
As shown in figure 8, first, in the step s 21, judging whether abnormality diagnostic execution condition is true.It is abnormality diagnostic Execution condition, for example, the temperature in upstream side exhaust emission control catalyst 20 is active temperature (activation temperature) or more and air-fuel ratio The temperature of sensor 40,41 and NOx sensor 46 is set up when being active temperature or more.Upstream side exhaust emission control catalyst 20 Temperature is detected or is based on for example, the temperature sensor of the temperature by detecting upstream side exhaust emission control catalyst 20 is (not shown) The output of the temperature sensor (not shown) of the temperature of cooling water of internal combustion engine is detected to estimate.It is determined as exception in the step s 21 In the case that the execution condition of diagnosis is invalid, finishing control program.
On the other hand, in the case of being determined as that abnormality diagnostic execution condition is set up in the step s 21, step is entered S22.In step S22, whether judgement air-fuel ratio correction amount AFC is positive value, i.e. whether target air-fuel ratio is dilute air-fuel ratio.In step Be determined as the case where air-fuel ratio correction amount AFC is positive value in rapid S22, in the case that i.e. target air-fuel ratio is dilute air-fuel ratio, not into The abnormity diagnosis of row upstream side exhaust emission control catalyst 20, therefore finishing control program.On the other hand, judge in step S22 The case where for air-fuel ratio correction amount AFC being negative value, in the case that i.e. target air-fuel ratio is dense air-fuel ratio, enters step S23.
In step S23, judgement base is calculated based on the temperature of upstream side exhaust emission control catalyst 20, inhaled air volume etc. Quasi- value Cnoxref.Determinating reference value Cnoxref is for example configured to:The temperature of upstream side exhaust emission control catalyst 20 is lower, separately Outside, inhaled air volume is more, then it is bigger.Furthermore determinating reference value Cnoxref can also be preset certain value, because This, omits step S23 in this case.
Then, in step s 24, whether the NOx concentration Cnox that judgement is detected by NOx sensor 46 is in step S23 The determinating reference value Cnoxref or more of middle calculating.In step s 24, the NOx concentration Cnox detected is less than determinating reference value In the case of Cnoxref, 20 no exceptions of upstream side exhaust emission control catalyst, therefore finishing control program.
On the other hand, in step s 24, the NOx concentration Cnox detected is the situation of determinating reference value Cnoxref or more Under, enter step S25.In step s 25, with reference to the information of past control program, judge detected NOx concentration Cnox is whether the state of determinating reference value Cnoxref or more continuously continues.The step is for preventing:Since NOx is sensed Overall noise of device 46 etc. and cause detected NOx concentration Cnox to become determinating reference value Cnoxref or more for the moment, to The misinterpretation of this abnormal intention of upstream side exhaust emission control catalyst 20 is carried out.Specifically, for example, in repeatedly control program In, in the case of being continuously determined as that the NOx concentration Cnox detected is determinating reference value Cnoxref or more in step s 24, It is determined as that detected NOx concentration Cnox is that the state of determinating reference value Cnoxref or more continuously continues.
It is determined as that detected NOx concentration Cnox is that the state of determinating reference value Cnoxref or more does not have in step s 25 Have in the case of continuously continuing, finishing control program.On the other hand, it is determined as detected NOx concentration in step s 25 Cnox is in the case that the state of determinating reference value Cnoxref or more continuously continues, to enter step S26.In step S26 In, it is determined as that exception has occurred in upstream side exhaust emission control catalyst 20, such as light emergency warning lamp.
< second embodiments >
Then, with reference to Fig. 9 and Figure 10, the emission-control equipment that second embodiment is related to is illustrated.Second implements In the emission-control equipment that composition and control in the emission-control equipment that mode is related to substantially are related to first embodiment Composition and control it is same, therefore below centered on the part different from the emission-control equipment that first embodiment is related into Row explanation.
Fig. 9 is upstream side exhaust emission control catalyst when indicating to carry out the abnormity diagnosis of upstream side exhaust emission control catalyst 20 The variation of 20 oxygen occlusion amount etc., same as Fig. 7 sequence diagram.In fig.9, it is also sensed about by NOx in the same manner as Fig. 7 The NOx concentration that device 46 detects, the solid line in figure indicate the normal situation of upstream side exhaust emission control catalyst 20, the dotted line in figure Indicate the abnormal situation of upstream side exhaust emission control catalyst 20.
When target air-fuel ratio is switched to dilute air-fuel ratio from dense air-fuel ratio (such as moment t1) nearby, by target air-fuel ratio When being switched to dense air-fuel ratio from dilute air-fuel ratio (such as moment t2) near, the atmosphere in upstream side exhaust emission control catalyst 20 is significantly Ground changes.Thus, with the variation of the atmosphere in upstream side exhaust emission control catalyst 20, although upstream side exhaust emission control catalyst 20 is normal, but the possibility for having NOx to be flowed out from upstream side exhaust emission control catalyst 20.
Therefore, in the emission-control equipment that this second embodiment is related to, target air-fuel ratio is only being set as dense sky During combustion ratio (such as moment t2~t3) in, have left target air-fuel ratio be switched to dense air-fuel ratio from dilute air-fuel ratio when (such as moment t2) and when target air-fuel ratio is switched to dilute air-fuel ratio from dense air-fuel ratio (such as moment t3) during (in figure During X2), carry out the abnormity diagnosis of upstream side exhaust emission control catalyst 20.That is, in the present embodiment, only by target empty (for example, half during) among during entire carries out during firing the part than the center in during being set as dense air-fuel ratio The abnormity diagnosis of upstream side exhaust emission control catalyst 20.
Specifically, quite during same period X2During, based on dense from target air-fuel ratio to be switched to from dilute air-fuel ratio When air-fuel ratio (such as moment t2) set by the time.Become when the time of passing through from having switched target air-fuel ratio When for the 1st more than the stipulated time, the abnormity diagnosis of upstream side exhaust emission control catalyst 20 is proceeded by, until reaching the second regulation Terminate abnormity diagnosis until time.Here, the 1st stipulated time was set to for example be switched to dense air-fuel ratio from by target air-fuel ratio Play 1/8 to 1/3 or so of the commonly required time wanted until being switched to dilute air-fuel ratio.In addition, the 2nd stipulated time was set Be set to for example from target air-fuel ratio is switched to dense air-fuel ratio play be switched to dilute air-fuel ratio until it is commonly required want when Between 2/3 to 7/8 or so.Thereby, it is possible to inhibit:Due to the switching with target air-fuel ratio, NOx from upstream side, urge by exhaust gas purification Agent 20 flows out, and it is that abnormal situation has occurred in upstream side exhaust emission control catalyst 20 to lead to wrong diagnosis.
Furthermore in the above example, based on from target air-fuel ratio is switched to dense air-fuel ratio by the time come It sets and is equivalent to period X2During, but can also be based on being set such as accumulated oxygen is in shortage.In this case, when from When accumulated oxygen from when having switched target air-fuel ratio is in shortage to become the 1st specified amount or less, upstream side exhaust gas purification is proceeded by The abnormity diagnosis of catalyst 20 terminates abnormity diagnosis until reaching 2 specified amount.Here, for the 1st specified amount is set Such as absorb oxygen amount 1/8 to 1/3 or so of upstream side exhaust emission control catalyst 20.In addition, the 2nd specified amount is set to for example Absorb oxygen amount 2/3 to 7/8 or so of upstream side exhaust emission control catalyst 20.
Figure 10 is to indicate the abnormality diagnostic exception of the present embodiment for carrying out upstream side exhaust emission control catalyst 20 The flow chart of the control program of diagnosis control.The control program of diagram is spaced execution at regular intervals.The step S31 of Figure 10, S32 is same as step S21, S22 of Fig. 8, in addition, step S34~S37 of Figure 10 is same as step S23~S26 of Fig. 8, therefore These steps are omitted the description.
It is determined as that the case where air-fuel ratio correction amount AFC is negative value, i.e. target air-fuel ratio is dense air-fuel ratio in step s 32 In the case of, enter step S33.In step S33, judgement current time (present moment) whether during with above-mentioned X2Phase When it is specific during.Current time whether during specific, be based on from by target air-fuel ratio be switched to dense air-fuel compared with Time, and/or accumulation oxygen excess Σ OED in shortage judge.It is determined as current time not in above-mentioned spy in step S33 In the case of during fixed, finishing control program.On the other hand, it is determined as current time in above-mentioned given period in step S33 In the case of interior, step S34 is entered.
< third embodiments >
Then, referring to Fig.1 1, the emission-control equipment being related to third embodiment illustrates.Third embodiment relates to And emission-control equipment in composition and the exhaust that is substantially related to first embodiment and second embodiment of control Composition and control in purifier is same, therefore the exhaust to be related to first embodiment and second embodiment below Purifier illustrates centered on different parts.
In above-mentioned first embodiment and second embodiment, in air-fuel ratio control, when downstream side air-fuel ratio senses When the output air-fuel ratio AFdwn of device 41 becomes dense judgement air-fuel ratio AFrich or less, target air-fuel ratio is switched from dense air-fuel ratio For dilute air-fuel ratio.Moreover, when accumulation oxygen excess Σ OED in shortage become switching a reference value OEDref or more, by target air-fuel Than being switched to dense air-fuel ratio from dilute air-fuel ratio.
In contrast, in the present embodiment, the switching from dense air-fuel ratio to dilute air-fuel ratio of target air-fuel ratio, same Timing (timing), i.e. downstream side air-fuel ratio sensor 41 output air-fuel ratio AFdwn become dense judgement air-fuel ratio AFrich It is carried out when following.On the other hand, the switching from dilute air-fuel ratio to dense air-fuel ratio of target air-fuel ratio is sensed in downstream side air-fuel ratio The output air-fuel ratio AFdwn of device 41 becomes carrying out when dilute judgement air-fuel ratio AFlean or more.
Even if in the case where having carried out such air-fuel ratio control, when target air-fuel ratio is set as dilute air-fuel ratio, Also there is upstream side exhaust emission control catalyst 20 that the possibility of HC poisonings occurs.Therefore, in the present embodiment, also by target empty Combustion is than (X during in Figure 11 during being set as dense air-fuel ratio1) or the specific period of a part in this period (be equivalent to State the specific period of second embodiment) carry out upstream side exhaust emission control catalyst 20 abnormity diagnosis.
The 4th embodiment > of <
Then, 2~Figure 15, the emission-control equipment being related to the 4th embodiment illustrate referring to Fig.1.4th implements Composition and control in the emission-control equipment that mode is related to substantially are related to first embodiment~third embodiment Composition and control in emission-control equipment is same therefore different with the emission-control equipment being related to from these embodiments below Part centered on illustrate.
"The type of catalyst degradation"
The deterioration of upstream side exhaust emission control catalyst 20 is caused in addition to as described above by the sintering of catalyst noble metal Deterioration other than, can also enumerate in absorbing the sulphur ingredient in exhaust and the S that generates due to upstream side exhaust emission control catalyst 20 Poison deterioration.
With regard to caused by the sintering by catalyst noble metal deteriorate for, once caused due to sintering catalyst noble metal that If this is combined, then in the state that upstream side exhaust emission control catalyst 20 is loaded into vehicle, it can not make to combine Catalyst noble metal restores.Therefore, it can be said that deterioration caused by sintering by catalyst noble metal is the deterioration that can not restore (as described above, also such deterioration is known as " permanent deterioration ").
On the other hand, for S poisoning deteriorations, even if sulphur ingredient can if occlusion by upstream side exhaust emission control catalyst 20 It is enough (for example, the temperature of upstream side exhaust emission control catalyst 20 is made to become more than a certain amount of high temperature, and to make under given conditions The air-fuel ratio for the exhaust that exhaust emission control catalyst 20 flows into the upstream side becomes dense air-fuel ratio) so that absorbed sulphur ingredient is detached from. Therefore, it can be said that S poisoning deteriorations are the deteriorations that can restore.
Furthermore below by the deterioration of the upstream side exhaust emission control catalyst 20 comprising these permanent deteriorations and S poisoning deteriorations Referred to as total deterioration.Therefore, when the degradation caused by permanently deteriorating of upstream side exhaust emission control catalyst 20 is got higher, upstream Total degradation of side exhaust emission control catalyst 20 is got higher, similarly, when upstream side exhaust emission control catalyst 20 be poisoned by S it is bad When degradation caused by changing is got higher, total degradation of upstream side exhaust emission control catalyst 20 is got higher.
"The deterioration estimated by presumption by deteriorating"
As described above, the target air-fuel ratio for the exhaust that exhaust emission control catalyst 20 flows into the upstream side is being set as dense Air-fuel ratio, and the oxygen occlusion amount OSA of upstream side exhaust emission control catalyst 20 do not become zero nearby when (that is, using upstream side The air-fuel ratio of the oxygen occlusion capacity of exhaust emission control catalyst 20, the exhaust flowed out from upstream side exhaust emission control catalyst 20 becomes managing When by near air-fuel ratio), it can be judged as that the concentration of the NOx flowed out from upstream side exhaust emission control catalyst 20 is higher, then upstream Side exhaust emission control catalyst 20 more greatly deteriorates.In addition, if not considering that HC is poisoned, exhaust gas purification will urge to the upstream side The target air-fuel ratio for the exhaust that agent 20 flows into is set as dilute air-fuel ratio, and the oxygen of upstream side exhaust emission control catalyst 20 absorbs Amount OSA does not become maximum when can absorb near oxygen amount Cmax (that is, the oxygen using upstream side exhaust emission control catalyst 20 absorbs energy When the air-fuel ratio of power, the exhaust flowed out from upstream side exhaust emission control catalyst 20 becomes near chemically correct fuel), can also it judge The concentration of NOx to be flowed out from upstream side exhaust emission control catalyst 20 is higher, then upstream side exhaust emission control catalyst 20 is more significantly Ground deteriorates.That is, upstream side exhaust gas purification can be estimated based on the concentration of the NOx flowed out from upstream side exhaust emission control catalyst 20 The degradation of catalyst 20.
Think that the degradation of the upstream side exhaust emission control catalyst 20 estimated at this time is bad caused by permanently deteriorating Change degree.I.e., it is believed that the degradation of the upstream side exhaust emission control catalyst 20 estimated at this time is the exclusion among total deterioration The degradation of the upstream side exhaust emission control catalyst 20 of influence caused by S poisoning deteriorations.Hereinafter, to the reason thought in this way By illustrating.
Figure 12 is in the case of indicating target air-fuel ratio for dense air-fuel ratio, inhaled air volume and is examined by NOx sensor 46 The relationship for the NOx concentration measured, the same figure with 5.Square marks in Figure 12 indicate upstream side exhaust emission control catalyst 20 Relationship in the case of normal.On the other hand, the circular mark in Figure 12 indicates that upstream side exhaust emission control catalyst 20 is not sent out Raw S poisonings deteriorate but the relationship in the case of permanent deterioration have occurred, and triangular marker indicates upstream side exhaust emission control catalyst 20 without occurring permanently to deteriorate but the relationship in the case of S poisoning deteriorations having occurred.
As can be seen from Figure 12, it in the case where permanent deterioration has occurred in upstream side exhaust emission control catalyst 20, is arranged with upstream side The normal situation of gas cleaning catalyst 20 is compared, and the NOx concentration detected by NOx sensor 46 is high.This is because as it is above-mentioned that Sample is flowed out in the case where permanent deterioration has occurred in upstream side exhaust emission control catalyst 20 from upstream side exhaust emission control catalyst 20 NOx amount increase caused by.On the other hand, in the case where S poisoning deteriorations have occurred in upstream side exhaust emission control catalyst 20, The NOx concentration detected from NOx sensor 46 becomes degree identical with the situation that upstream side exhaust emission control catalyst 20 is normal. Thought according to such result, the concentration based on the NOx flowed out from upstream side exhaust emission control catalyst 20 and the upstream side that estimates The degradation of exhaust emission control catalyst 20 is by permanently deteriorating caused degradation.
The concentration of NOx for occurring to flow out from upstream side exhaust emission control catalyst 20 in this wise is drawn according to by permanently deteriorating The degradation that rises and change and will not be poisoned deterioration according to S and change the mechanism of this phenomenon, can not get across. However, it is possible to think that there is a phenomenon where such by following such mechanism.
Figure 13 is the sectional view showed schematically near the surface of exhaust emission control catalyst.As shown in (a) of Figure 13, arranging It is carried on a shoulder pole as catalyst noble metal on the carrier 50 for having supported the substance with oxygen occlusion capacity on the surface of gas cleaning catalyst It is loaded with palladium 51 and rhodium 52.When permanent deterioration occurs in the exhaust emission control catalyst constituted in this way, it is supported on carrier 50 The particle of palladium 51 is each other and the particle of rhodium 52 is combined due to sintering each other.As a result, the surface area of palladium 51 and rhodium 52 becomes Small, the catalytic action of these catalyst noble metals reduces.
Sectional view when (b) of Figure 13 shows that S poisoning deteriorations have occurred.As shown in (b) of Figure 13, sulphur ingredient 53, which has, to be inhaled It is attached on the surface of palladium 51 and is not easy to be adsorbed on the tendency on the surface of rhodium 52.Therefore, occur when in exhaust emission control catalyst When S poisoning deteriorations, the catalytic action of palladium 51 reduces, but the catalytic action of rhodium 52 do not reduce so.Here, in exhaust The reduction of NOx is mainly promoted by rhodium 52.Thus, even if S poisoning deteriorations have occurred in exhaust emission control catalyst, caused by rhodium 52 The reduction of NOx also do not limited so.According to such mechanism, it is believed that even if occurring in S as shown in Figure 12 Poison deterioration, the concentration of the NOx flowed out from upstream side exhaust emission control catalyst 20 will not be poisoned according to S to be deteriorated and changes.
"Control in 4th embodiment"
If it is considered that above such phenomenon, then it can be based on the NOx's flowed out from upstream side exhaust emission control catalyst 20 Concentration come estimate upstream side exhaust emission control catalyst 20 by permanently deteriorating caused degradation.But it is arranging to the upstream side Gas cleaning catalyst 20 flow into exhaust air-fuel ratio be dilute air-fuel ratio in the case of, sometimes as described above due to HC be poisoned and The degradation of upstream side exhaust emission control catalyst 20 cannot be accurately estimated according to NOx concentration.Therefore, in present embodiment In, the NOx sensor when air-fuel ratio for being not based on the exhaust that exhaust emission control catalyst 20 flows into the upstream side is dilute air-fuel ratio 46 output, but based on exhaust emission control catalyst 20 to the upstream side flow into exhaust air-fuel ratio be dense air-fuel ratio when NOx The output of sensor 46, come estimate upstream side exhaust emission control catalyst 20 by permanently deteriorating caused degradation.
Figure 14 is to indicate inhaled air volume and the NOx concentration detected by NOx sensor 46 and upstream side exhaust gas purification The figure of the relationship of degradation caused by permanently deteriorating of catalyst 20.In the present embodiment, using such relationship, base In inhaled air volume and NOx concentration come estimate upstream side exhaust emission control catalyst 20 by permanently deteriorating caused degradation. As shown in figure 14, when the air-fuel ratio of the exhaust flowed into exhaust emission control catalyst 20 to the upstream side is dense air-fuel ratio, by permanent bad Degradation is estimated as follows caused by changing:The NOx concentration detected by NOx sensor 46 is higher, then upstream side is vented The degradation caused by permanently deteriorating of cleaning catalyst 20 is higher.In addition, as shown in figure 14, it is bad caused by permanently deteriorating Change degree is estimated as follows:Inhaled air volume into combustion chamber 5 is fewer, then upstream side exhaust emission control catalyst 20 by Degradation is higher caused by permanent deterioration.
Moreover, being determinating reference value Cnoxref or more in the NOx concentration detected by NOx sensor 46 as shown in figure 14 In the case of, degradation is very high caused by permanently deteriorating, it is determined that occurring for upstream side exhaust emission control catalyst 20 Exception.Determinating reference value Cnoxref at this time is for example set in the same manner as the determinating reference value Cnoxref in first embodiment It is fixed.Therefore, it is more at most bigger to be configured to inhaled air volume by determinating reference value Cnoxref.
Figure 15 is to indicate to carry out the presumption of degradation caused by permanently deteriorating of upstream side exhaust emission control catalyst 20 Degradation presumption control control program flow chart.The control program of diagram is spaced execution at regular intervals.
As shown in figure 15, first, in step S41, whether the execution condition of judgement degradation presumption control is true.It is bad The execution condition of change degree presumption control, for example, it is same as the abnormality diagnostic execution condition in the step S21 of Fig. 8.In step In the case of being determined as that abnormality diagnostic execution condition is set up in S41, step S42 is entered.
In step S42, whether judgement air-fuel ratio correction amount AFC is positive value, i.e. exhaust emission control catalyst 20 to the upstream side Whether the exhaust of inflow is dilute air-fuel ratio.Be determined as in step S42 air-fuel ratio correction amount AFC be positive value in the case of, not into The presumption of row degradation is with regard to finishing control program.On the other hand, it is determined as that air-fuel ratio correction amount AFC is negative in step S42 In the case of value, step S43 is entered.
Exporting to calculate the inhaled air volume into combustion chamber 5 in step S43, such as based on air flow meter 39, And determinating reference value Cnoxref is calculated based on the inhaled air volume calculated.Determinating reference value Cnoxref is as described above It calculates so that inhaled air volume is more, then it is bigger.
Then, in step S44, judge whether the NOx concentration Cnox detected by NOx sensor 46 is in step S43 The determinating reference value Cnoxref or more of middle calculating.Furthermore the NOx concentration Cnox used in step S43 can also be to provide The average value etc. for the NOx concentration that time is detected by NOx sensor 46.It is determined as detected NOx concentration in step S43 In the case that Cnox is less than determinating reference value Cnoxref, step S45 is entered.
In step S45, based on the inhaled air volume calculated in step S43 and the NOx detected by NOx sensor 46 Concentration C nox calculates being caused by permanently deteriorating for upstream side exhaust emission control catalyst 20 using mapping graph shown in Figure 14 (map) Degradation, finishing control program.
On the other hand, be determined as in step S43 detected NOx concentration Cnox be determinating reference value Cnoxref with In the case of upper, step S46 is entered.In step S46, it is determined as that exception has occurred in upstream side exhaust emission control catalyst 20, Such as light emergency warning lamp.
The 5th embodiment > of <
Then, 6~Figure 19, the emission-control equipment being related to the 5th embodiment illustrate referring to Fig.1.5th implements What composition and control in the emission-control equipment that mode is related to substantially were related to third embodiment and the 4th embodiment Composition and control in emission-control equipment is same therefore different with the emission-control equipment being related to from these embodiments below Part centered on illustrate.
"The presumption method of S poisoning deteriorations"
As described above, it for the deterioration of upstream side exhaust emission control catalyst 20, is generally divided, including permanent bad Change and S poisonings deteriorate.Wherein, about permanent deterioration, can journey be deteriorated to estimate it using the method that the 4th embodiment is related to Degree.But the method that the 4th embodiment is related to cannot estimate the degradation caused by S poisoning deteriorations.Therefore, in this implementation In mode, method of the presumption by the caused degradation of S poisoning deteriorations is provided.
Figure 16 is in the case of having carried out air-fuel ratio control same as third embodiment shown in Figure 11, air-fuel ratio The sequence diagram of correction amount etc..As shown in figure 16, in the present embodiment, in the output air-fuel ratio of downstream side air-fuel ratio sensor 41 When AFdwn becomes dense judgement air-fuel ratio AFrich or less, air-fuel ratio correction amount AFC is switched from dense setting correction amount AFCrich For dilute setting correction amount AFClean.Therefore, target air-fuel ratio is switched to dilute air-fuel ratio from dense air-fuel ratio at this time, therefore upstream The air-fuel ratio for the exhaust that side exhaust emission control catalyst 20 flows into changes from dense air-fuel ratio to dilute air-fuel ratio.On the other hand, in this reality It applies in mode, when in downstream side, the output air-fuel ratio AFdwn of air-fuel ratio sensor 41 becomes dilute judgement air-fuel ratio AFlean or more, Air-fuel ratio correction amount AFC is switched to dense setting correction amount AFCrich from dilute setting correction amount AFClena.Therefore, target at this time Air-fuel ratio is switched to dense air-fuel ratio, therefore the air-fuel ratio for the exhaust that exhaust emission control catalyst 20 flows into the upstream side from dilute air-fuel ratio Change from dilute air-fuel ratio to dense air-fuel ratio.
Here, from the output air-fuel ratio AFdwn in downstream side air-fuel ratio sensor 41 be dense judgement air-fuel ratio AFrich with The air-fuel ratio variation for the exhaust that exhaust emission control catalyst 20 flows into the upstream side in the state of lower is that dilute air-fuel ratio plays downstream side Until the output air-fuel ratio AFdwn of air-fuel ratio sensor 41 becomes dilute judgement air-fuel ratio AFlean or more, it is vented by upstream side net Change the amount for the oxygen that catalyst 20 absorbs, indicates the oxygen amount that upstream side exhaust emission control catalyst 20 can absorb.That is, in figure 16, Such as moment t1To moment t2During accumulation oxygen excess Σ OED in shortage (the Σ OED in figure1) indicate that upstream side exhaust is net Change the oxygen amount that catalyst 20 can absorb.
Similarly, it is dilute judgement air-fuel ratio AFlean from the output air-fuel ratio AFdwn in downstream side air-fuel ratio sensor 41 The air-fuel ratio variation for the exhaust that exhaust emission control catalyst 20 flows into the upstream side in the state of above is that dense air-fuel ratio plays downstream Until the output air-fuel ratio AFdwn of side air-fuel ratio sensor 41 becomes dense judgement air-fuel ratio AFrich or less, it is vented from upstream side The amount for the oxygen that cleaning catalyst 20 discharges, also illustrates that the amount for the oxygen that upstream side exhaust emission control catalyst 20 can absorb.That is, scheming In 16, such as moment t2To moment t3During accumulation oxygen excess Σ OED in shortage (the Σ OED in figure2) indicate upstream side row The oxygen amount that gas cleaning catalyst 20 can absorb.
Additionally, it is known that the oxygen amount that absorbs of exhaust emission control catalyst becomes according to total degradation of exhaust emission control catalyst Change.In particular, total degradation of the exhaust emission control catalyst comprising above-mentioned permanent deterioration and S poisoning deteriorations is higher, exhaust The oxygen amount that absorbs of cleaning catalyst is more reduced.Therefore, as described above, total deterioration journey of upstream side exhaust emission control catalyst 20 Degree is higher, and the oxygen amount that absorbs based on the accumulation oxygen excess Σ OED in shortage upstream side exhaust emission control catalysts 20 calculated more subtracts It is few.Therefore, as described above, if it is possible to which the oxygen amount that absorbs for calculating upstream side exhaust emission control catalyst 20 can be then based on The upstream side exhaust emission control catalyst 20 calculated absorbs oxygen amount to estimate the total bad of upstream side exhaust emission control catalyst 20 Change degree.
Moreover, if other than the degradation caused by permanently deteriorating of upstream side exhaust emission control catalyst 20, go back Total degradation of upstream side exhaust emission control catalyst 20 can be found out in this wise, then can calculate upstream based on these results The degradation caused by S poisoning deteriorations of side exhaust emission control catalyst 20.
"Control in 5th embodiment"
Therefore, according to the present embodiment, first, carry out carrying out total degradation of upstream side exhaust emission control catalyst 20 Total degradation presumption control of presumption.In total degradation presumption control in the present embodiment, it is vented based on upstream side Cleaning catalyst 20 absorb oxygen amount or corresponding to can absorb oxygen amount and the parameter value that changes (such as accumulation oxygen excess is insufficient Amount), to estimate total degradation of upstream side exhaust emission control catalyst 20.Upstream side exhaust emission control catalyst 20 absorbs oxygen Amount or the parameter value that changes corresponding to which, such as output air-fuel ratio AFdwn as downstream side air-fuel ratio sensor 41 is from dense Judgement air-fuel ratio AFrich states below play until becoming dilute judgement air-fuel ratio AFlean or more by upstream side exhaust gas purification The output of oxygen amount or the parameter value or downstream side air-fuel ratio sensor 41 that change corresponding to the oxygen amount that catalyst 20 absorbs Air-fuel ratio AFdwn from it is dilute judgement air-fuel ratio AFlean or more state play until becoming dense judgement air-fuel ratio AFrich or less from Oxygen amount or the parameter value that changes corresponding to the oxygen amount that upstream side exhaust emission control catalyst 20 discharges and calculate.
Moreover, the upstream side exhaust emission control catalyst 20 deduced based on the output according to NOx sensor 46 by forever Degradation and the upstream side for absorbing oxygen amount and deducing according to upstream side exhaust emission control catalyst 20 caused by deterioration long Total degradation of exhaust emission control catalyst 20, to calculate being poisoned caused by deterioration by S for upstream side exhaust emission control catalyst 20 Degradation.
Figure 17 and Figure 18 indicates inhaled air volume and can absorb oxygen amount OSC and upstream side exhaust emission control catalyst 20 The figure of the relationship of degradation caused by S poisoning deteriorations.In the present embodiment, empty based on sucking using such relationship Tolerance estimates the degradation caused by S poisoning deteriorations of upstream side exhaust emission control catalyst 20 with that can absorb oxygen amount OSC.It is special It is not that Figure 17 shows pass of the degradation caused by permanently deteriorating of upstream side exhaust emission control catalyst 20 in the case of low System, Figure 18 show the pass in the case of the degradation height caused by permanently deteriorating of upstream side exhaust emission control catalyst 20 System.Furthermore the dotted line in Figure 18 indicates that the degradation caused by permanently deteriorating of upstream side exhaust emission control catalyst 20 is low In the case of relationship, i.e. relationship in Figure 17.
As shown in Figure 17 and Figure 18, the degradation caused by S poisoning deteriorations estimates as described below:Oxygen amount can be absorbed OSC is more, that is, total degradation of upstream side exhaust emission control catalyst 20 is lower, then the degradation caused by S poisoning deteriorations It is lower.In addition, as shown in Figure 17 and Figure 18, degradation estimates as described below caused by S poisoning deteriorations:To combustion chamber 5 Interior inhaled air volume is fewer, then the degradation caused by S poisoning deteriorations of upstream side exhaust emission control catalyst 20 is higher.
In addition, relationship is it is found that in upstream side exhaust emission control catalyst 20 shown in relationship and Figure 18 shown in comparison diagram 17 By degradation height caused by permanently deteriorating in the case of (Figure 18), with the degradation compared with low situation (Figure 17), phase For oxygen amount OSC can be absorbed, that is, relative to total degradation of upstream side exhaust emission control catalyst 20, caused by S poisoning deteriorations Degradation be deduced low.Therefore, in the case of the degradation height caused by permanently deteriorating (Figure 18), with the deterioration The low situation of degree (Figure 17) is compared, even if it is identical to absorb oxygen amount OSC, that is, even if upstream side exhaust emission control catalyst 20 Total degradation is identical, and degradation is also deduced low caused by S poisoning deteriorations.
In addition, in the present embodiment, when the degradation caused by S poisoning deteriorations becomes more than centainly, carrying out The sulfur poisoning of trip side exhaust emission control catalyst 20 becomes larger the judgement of this intention.Specifically, in it can absorb oxygen amount OSC and become In the case of malicious benchmark oxygen amount OSCref is below, that is, total degradation of upstream side exhaust emission control catalyst 20 becomes base of being poisoned In the case that quasi- value is above, the sulfur poisoning for carrying out upstream side exhaust emission control catalyst 20 becomes larger the judgement of this intention.Poisoning base Quasi- oxygen amount OSCref, i.e. poisoning a reference value are based on upstream side exhaust emission control catalyst 20 by permanently deteriorating caused degradation To set.Specifically, poisoning benchmark oxygen amount OSCref be configured to by degradation caused by permanently deteriorating more it is big then itself more It is small.Therefore, poisoning a reference value is configured to that more big then it is bigger by degradation caused by permanently deteriorating.
In the case where the sulfur poisoning for having carried out upstream side exhaust emission control catalyst 20 becomes larger the judgement of this intention, in order to So that sulphur ingredient is detached from from upstream side exhaust emission control catalyst 20, carry out sulphur disengaging processing, in addition, in order to inhibit upstream side exhaust net Change catalyst 20 and also absorb sulphur ingredient, carries out absorbing inhibition processing.In sulphur disengaging processing, for example, making to be vented to the upstream side net Changing the air-fuel ratio for the exhaust that catalyst 20 flows into becomes dense air-fuel ratio, and makes the temperature liter of upstream side exhaust emission control catalyst 20 Temperature is with so that it becomes sulphur is detached from temperature or more.In addition, in absorbing inhibition processing, above-mentioned basic air-fuel ratio control is being carried out When, reduce the dense degree of dense setting air-fuel ratio, and increase dilute degree of dilute setting air-fuel ratio.Exhaust is net to the upstream side as a result, The time that the air-fuel ratio for the exhaust that change catalyst 20 flows into becomes dense air-fuel ratio is relatively elongated, as a result, it is difficult to become sulphur ingredient To be absorbed in upstream side exhaust emission control catalyst 20.
According to the present embodiment, with permanent deterioration, total deterioration the deterioration caused by S poisoning deteriorations can be estimated with separating Degree.Thereby, it is possible to carry out sulphur disengaging processing etc. based on the degradation caused by S poisoning deteriorations, so can be appropriate Timing carry out sulphur disengaging processing.Here, sulphur disengaging is handled, can be recruited due to heating of upstream side exhaust emission control catalyst 20 etc. Cause the deterioration of fuel consumption.In this regard, according to the present embodiment, due to carrying out sulphur disengaging processing in timing appropriate, can press down The deterioration by unnecessarily carrying out the fuel consumption caused by sulphur is detached from processing with high-frequency is made, in addition, can inhibit at sulphur disengaging The case where underfrequency of reason reduces to the detergent power of upstream side exhaust emission control catalyst 20.
Figure 19 is to indicate to judge the degradation caused by S poisoning deteriorations of upstream side exhaust emission control catalyst 20 S poisoning judgement control control program flow chart.The control program of diagram is spaced execution at regular intervals.Shown in Figure 19 Step S51~S56 it is same as step S41~S46 of Figure 15, and the description is omitted.
In step S55, calculate upstream side exhaust emission control catalyst 20 by permanently deteriorating caused degradation, connect It, in step S57, using such mapping graph (map) as shown in Figure 17 and Figure 18, based on inhaled air volume and by permanent bad Change caused degradation to calculate poisoning benchmark oxygen amount OSCref.Furthermore at this point, can also use as shown in Figure 17 and Figure 18 Such mapping graph deteriorates caused degradation to calculate by S poisonings.
Then, in step S58, oxygen amount OSC can be absorbed to calculate based on accumulation oxygen excess Σ OED in shortage, and sentence That determines to be calculated absorbs whether oxygen amount OSC is the poisoning benchmark oxygen amount OSCref or less calculated in step S57.In step In the case of being judged to absorb oxygen amount OSC in S58 more than poisoning benchmark oxygen amount OSCref, finishing control program.On the other hand, It is that poisoning benchmark oxygen amount OSCref is below that oxygen amount OSC can be absorbed by, which being determined as in step S58, enters step S59. In step S59, to make sulphur ingredient execute sulphur disengaging processing from the disengaging of upstream side exhaust emission control catalyst 20.In addition, in sulphur Be detached from processing execution condition it is invalid to cannot execute at once sulphur disengaging processing in the case of, in order to inhibit upstream side to be vented Cleaning catalyst 20 also absorbs sulphur ingredient and absorb inhibition processing, until sulphur is detached from the execution condition establishment of processing.
< sixth embodiments >
Then, with reference to Figure 20 and Figure 21, the emission-control equipment that sixth embodiment is related to is illustrated.6th implements In the emission-control equipment that composition and control in the emission-control equipment that mode is related to substantially are related to the 5th embodiment Composition and control it is same, therefore centered on parts different by the emission-control equipment being related to from the 5th embodiment below into Row explanation.
In the emission-control equipment that the 5th embodiment is related to, total degradation of upstream side exhaust emission control catalyst 20 Presumption be that oxygen amount is absorbed to carry out based on upstream side exhaust emission control catalyst 20.But upstream side exhaust gas purification is urged The presumption of total degradation of agent 20 can also use different methods to carry out.Therefore, net in the exhaust of sixth embodiment During makeup is set, the method different using the emission-control equipment being related to from the 5th embodiment is urged to carry out upstream side exhaust gas purification The presumption of total degradation of agent 20.
Figure 20 is that in the case of having carried out above-mentioned air-fuel ratio control, air-fuel ratio correction amount, upstream side exhaust gas purification are urged The sequence diagram of the oxygen occlusion amount OSA of agent 20 and the output air-fuel ratio AFdwn of downstream side air-fuel ratio sensor 41.In Figure 20 Shown in example, in moment t1In the past, air-fuel ratio correction amount AFC was set to dense setting correction amount AFCrich, therefore, to The air-fuel ratio for the exhaust that upstream side exhaust emission control catalyst 20 flows into becomes dense air-fuel ratio.Thus, upstream side exhaust gas purification catalysis The oxygen occlusion amount OSA of agent 20 is progressively decreased.
Then, when the oxygen occlusion amount OSA of upstream side exhaust emission control catalyst 20 tails off, in moment t1, downstream side air-fuel Become dense judgement air-fuel ratio AFrich or less than the output air-fuel ratio AFdwn of sensor 41.When downstream side air-fuel ratio sensor 41 Output air-fuel ratio AFdwn when becoming dense judgement air-fuel ratio AFrich or less, by air-fuel ratio correction amount AFC from dense setting correction amount AFCrich is switched to dilute setting correction amount AFClean, therefore, the sky for the exhaust that exhaust emission control catalyst 20 flows into the upstream side Combustion from dense air-fuel ratio to dilute air-fuel ratio than also switching.
But even if in moment t1Have switched air-fuel ratio correction amount AFC, the output air-fuel of downstream side air-fuel ratio sensor 41 Also do not rise at once than AFdwn, in moment t1It also continues to reduce later.This is because caused by following reason:Due to from internal combustion engine Main body 1 has distance to upstream side exhaust emission control catalyst 20, so even if switching air-fuel ratio correction amount AFC, is vented to the upstream side The air-fuel ratio for the exhaust that cleaning catalyst 20 flows into will not change at once as dilute air-fuel ratio.Moreover, at this point, downstream side air-fuel ratio The behavior of the output air-fuel ratio AFdwn of sensor 41 changes according to the state of upstream side exhaust emission control catalyst 20.
In fig. 20, the solid line in the output air-fuel ratio AFdwn of downstream side air-fuel ratio sensor 41 indicates upstream side exhaust The normal situation of cleaning catalyst 20, dotted line indicates the case where S poisoning deteriorations have occurred in upstream side exhaust emission control catalyst 20, single The case where permanent deterioration has occurred in chain-dotted line expression.
As indicated by the solid line shown in fig. 20, normal in upstream side exhaust emission control catalyst 20, export air-fuel ratio Low (the AFdwn in figure of minimum value that AFdwn is reached1), in addition, the integral of the difference of output air-fuel ratio AFdwn and chemically correct fuel Value is also big (by the area for the part that the straight line of output air-fuel ratio AFdwn and 14.6 surrounds).On the other hand, such as the dotted line in Figure 20 Shown in single dotted broken line, in the case that in upstream side, S poisonings deterioration or permanent deterioration has occurred in exhaust emission control catalyst 20, output Relatively high (the AFdwn in figure of minimum value that air-fuel ratio AFdwn is reached2), in addition, the difference of output air-fuel ratio and chemically correct fuel Integrated value is also relatively small.
Such phenomenon is generated due to the hydrogen in exhaust.It is known:In the air-fuel ratio sensor of carrying current formula, due to Diffusion velocity of the hydrogen in the diffusion law speed layer of air-fuel ratio sensor is fast, so when the hydrogen concentration in exhaust is high, air-fuel ratio passes The output air-fuel ratio of sensor deviates compared with the air-fuel ratio of actual exhaust to dense side.
On the other hand, in upstream side exhaust emission control catalyst 20, when the exhaust stream of dense air-fuel ratio is fashionable, pass through upstream side The catalytic action of exhaust emission control catalyst 20 and generate hydrogen.The activity of the noble metal catalyst of upstream side exhaust emission control catalyst 20 Higher, then the amount of the hydrogen generated at this time is more.Therefore, in upstream side exhaust emission control catalyst 20 without occurring in permanent deterioration, S When the deteriorations such as poison deterioration, more hydrogen can be generated.As a result, the output air-fuel ratio AFdwn of downstream side air-fuel ratio sensor 41 with The air-fuel ratio of actual exhaust is compared, and is significantly deviated to dense side, therefore, as indicated by the solid line shown in fig. 20, minimum value is lower. On the other hand, it when S poisonings deterioration and/or permanent deterioration has occurred in upstream side exhaust emission control catalyst 20, only generates a small amount of Hydrogen.As a result, the output air-fuel of downstream side air-fuel ratio sensor 41 to than AFdwn compared with the air-fuel ratio of actual exhaust, slightly It is micro- to be deviated to dense side, thus as in Figure 20 dotted line, shown in single dotted broken line, minimum value does not become so low.
"Control in sixth embodiment"
Therefore, in total degradation presumption control in the present embodiment, by air-fuel ratio correction amount AFC from dense setting After air-fuel ratio AFCrich is switched to dilute setting air-fuel ratio AFClean, that is, target air-fuel ratio is switched to dilute sky from dense air-fuel ratio After combustion ratio, during the convergence until output air-fuel ratio AFdwn of downstream side air-fuel ratio sensor 41 reaches chemically correct fuel, At least part of behavior of output air-fuel ratio AFdwn based on downstream side air-fuel ratio sensor 41 is net to estimate upstream side exhaust Change total degradation of catalyst 20.Specifically, as described above, based on the downstream side air-fuel ratio sensing during above-mentioned convergence The minimum value of the output air-fuel ratio AFdwn of device 41, estimates total degradation as described below:The minimum value is lower, then total deterioration Degree is lower.Alternatively, the integrated value of the difference based on output air-fuel ratio AFdwn and chemically correct fuel during above-mentioned convergence, such as with On estimate total degradation like that:The integrated value is bigger, then total degradation is lower.
Moreover, in the same manner as the emission-control equipment being related to above-mentioned 5th embodiment, based on according to NOx sensor 46 Export and the upstream side exhaust emission control catalyst 20 that deduces by permanently deteriorating caused degradation and according to downstream side sky The behavior than the output air-fuel ratio AFdwn of sensor 41 of combustion and the total deterioration journey of upstream side exhaust emission control catalyst 20 deduced Degree, to calculate the degradation caused by S poisoning deteriorations of upstream side exhaust emission control catalyst 20.
According to the present embodiment, in the same manner as above-mentioned 5th embodiment, it can separate ground with permanent deterioration, total deterioration Presumption degradation caused by S poisoning deteriorations.Thereby, it is possible to carry out sulphur disengaging processing in timing appropriate, can inhibit to consume The reduction of the deterioration of oil mass and the detergent power of upstream side exhaust emission control catalyst 20.
Figure 21 is indicated in the emission-control equipment that sixth embodiment is related to, to upstream side exhaust emission control catalyst 20 By S poisoning deterioration caused by degradation judged S poisoning judgement control control program flow chart.The control of diagram Processing procedure sequence is spaced execution at regular intervals.Step S61~S66 shown in Figure 21 is same as step S41~S46 of Figure 15, because This is omitted the description.
In step S65 calculate upstream side exhaust emission control catalyst 20 by permanently deteriorating caused degradation, then, In step S67, poisoning benchmark air-fuel ratio is calculated based on inhaled air volume and by permanently deteriorating caused degradation AFref.It is more at most lower (more to dense side) that poisoning benchmark air-fuel ratio AFref is configured to inhaled air volume, and is configured to The the degradation caused by permanently deteriorating the big then its higher (more to dilute side).Furthermore indicate that sucking is empty at this point, can also use The mapping graph of tolerance, the relationship of degradation caused by permanently deteriorating caused degradation and being deteriorated by S poisonings, to calculate Go out the degradation caused by S poisoning deteriorations.
Then, in step S68, the output air-fuel ratio of the downstream side air-fuel ratio sensor 41 during above-mentioned convergence is calculated Minimum value AFdwnmin, and judge whether calculated minimum value AFdwnmin is the poisoning benchmark calculated in step S67 Air-fuel ratio AFref or more.It is determined as the case where minimum value AFdwnmin is less than poisoning benchmark air-fuel ratio AFref in step S68 Under, finishing control program.On the other hand, it is determined as that minimum value AFdwnmin is poisoning benchmark air-fuel ratio AFref in step S68 In the case of above, step S69 is entered.In step S69, carries out sulphur disengaging processing, absorbs inhibition processing, finishing control journey Sequence.
The 7th embodiment > of <
Then, with reference to Figure 22 and Figure 23, the emission-control equipment being related to the 7th embodiment illustrates.7th implements Composition and control in the emission-control equipment that mode is related to substantially are related to the 5th embodiment and sixth embodiment Emission-control equipment in composition and control it is same, therefore below to be related to the 5th embodiment and sixth embodiment The different part of emission-control equipment centered on illustrate.
"The relationship of the sulphur ingredient containing ratio of fuel and the degradation caused by S poisoning deteriorations"
Sulphur ingredient containing ratio in the fuel supplied to internal combustion engine, it is different corresponding to each fuel.Using sulphur ingredient In the case of the high fuel of containing ratio, S poisoning deteriorations are easy to happen, on the other hand, are using the low fuel of sulphur ingredient containing ratio In the case of, it is not susceptible to S poisoning deteriorations.Thus, in order to inhibit deterioration and the upstream side exhaust emission control catalyst 20 of fuel consumption Purifying property reduction, need the control that internal combustion engine is changed according to sulphur ingredient containing ratio.Such as, it may be considered that:It is using In the case of the high fuel of sulphur ingredient containing ratio, compared with the case where using sulphur ingredient containing ratio low fuel, dense setting is improved The dense degree of air-fuel ratio, and reduce dilute degree of dilute setting air-fuel ratio.In order to be contained in this wise according to the sulphur ingredient in fuel Rate changes the control of internal combustion engine, needs to estimate the sulphur ingredient containing ratio in fuel.
Figure 22 is the sequence diagram of degradation caused by S poisoning deteriorations of upstream side exhaust emission control catalyst 20.Scheming In example shown in 22, in moment t1Supply to the fuel of the fuel tank (not shown) of internal combustion engine, in moment t2It is de- to carry out sulphur From processing.
As can be seen from Figure 22, the degradation caused by S poisoning deteriorations of upstream side exhaust emission control catalyst 20, with the time Process and rise.The reason is that:From the exhaust that combustion chamber 5 is discharged, the sulphur in the fuel supplied to combustion chamber 5 is corresponded to Ingredient containing ratio and contain sulphur ingredient, exhaust circulate in upstream side exhaust emission control catalyst 20 when, the sulphur ingredient is by upstream Side exhaust emission control catalyst 20 absorbs.If the sulphur ingredient containing ratio in the fuel supplied to combustion chamber 5 is certain, relative to Time, the degradation climbing caused by S poisoning deteriorations become substantially certain (more precisely, relative to sucking air The accumulated value of amount, the climbing of degradation caused by S poisoning deteriorations become substantially certain).Thus, as shown in figure 22, In moment t1In the past, the climbing (that is, slope in Figure 22) of degradation caused by S poisoning deteriorations was maintained certain.
Thereafter, when in moment t1When supplied to the fuel of fuel tank, moment t1Later with moment t1Than before, by S The climbing of degradation caused by poisoning deterioration is got higher.The reason is that in moment t1Sulphur ingredient in the fuel supplied contains There is rate to be higher than in moment t1Sulphur ingredient containing ratio in the fuel supplied in the past.
Thereafter, in moment t2Carry out sulphur disengaging processing.If carrying out sulphur disengaging processing, it is catalyzed by upstream side exhaust gas purification The sulphur ingredient that agent 20 absorbs is detached from.Thus, in moment t2Under, degradation substantially becomes zero caused by S poisoning deteriorations.Its Afterwards, when the duration of runs of internal combustion engine is elongated, the degradation caused by S poisoning deteriorations of upstream side exhaust emission control catalyst 20 Slowly rise again.
As described above, (or per unit incrementss of the accumulated value of inhaled air volume) are poisoned by S per unit time The ascending amount (climbing of degradation caused by S poisoning deteriorations) of degradation caused by deterioration, supplies with into combustion chamber 5 Sulphur ingredient containing ratio in the fuel given is proportional.Therefore, by calculating the deterioration caused by S poisoning deteriorations per unit time The climbing of degree, it will be able to calculate the sulphur ingredient containing ratio in fuel.
In particular, when supplied to the fuel of fuel tank, the sulphur ingredient containing ratio in the fuel supplied to combustion chamber 5 Also change, thus be preferably based on just carried out to the fuel of fuel tank supply after per unit time by S be poisoned deteriorate The climbing of caused degradation calculates the sulphur ingredient containing ratio in fuel.In addition, when carrying out sulphur disengaging processing, it is upper The sulphur ingredient that trip side exhaust emission control catalyst 20 absorbs substantially becomes zero, the degradation energy caused by S poisoning deteriorations at this time It is enough extremely accurate to estimate.It is therefore preferable that based on sulphur disengaging processing just after per unit time by S poisoning deterioration draw The climbing of degradation calculate the sulphur ingredient containing ratio in fuel.
"Control in 7th embodiment"
Therefore, in the present embodiment, containing ratio presumption control is executed, in containing ratio presumption control, is based on phase For the accumulated value of time or inhaled air volume variation, upstream side exhaust emission control catalyst 20 by S poisoning deterioration cause Degradation passage, to estimate the sulphur ingredient containing ratio into the fuel that internal combustion engine supplies.In particular, pushing away as described below It is fixed:Variation relative to time or the accumulated value of inhaled air volume, upstream side exhaust emission control catalyst 20 be poisoned by S deteriorates Caused degradation is bigger (climbing of degradation caused by S poisoning deteriorations is higher), then the sulphur ingredient in fuel contains There is rate higher.
In addition, in present embodiment, containing ratio presumption control is in the sulphur for making to be absorbed by upstream side exhaust emission control catalyst 20 The sulphur that ingredient is detached from is detached from after treatment and starts.Alternatively, in the present embodiment, containing ratio presumption control is to fuel tank Fuel starts after supplying.
It according to the present embodiment, can be based on the deterioration caused by S poisoning deteriorations of upstream side exhaust emission control catalyst 20 The passage of degree, accurately to estimate the sulphur ingredient containing ratio in fuel.In addition, laggard by just having terminated in sulphur disengaging processing The presumption control of row containing ratio, can more accurately estimate the sulphur ingredient containing ratio in fuel.
Figure 23 is the degradation caused by S poisoning deteriorations indicated for calculating upstream side exhaust emission control catalyst 20 S poisoning degradations calculate the flow chart of the control program of control.In order to calculate the sulphur ingredient containing ratio in fuel, need to calculate The degradation caused by S poisoning deteriorations of upstream side exhaust emission control catalyst 20, therefore execute this control.The control journey of diagram Sequence executes at a time interval.Step S71~S76 shown in Figure 23 is same as step S41~S46 of Figure 15, therefore saves Slightly illustrate.
In step S75 calculate upstream side exhaust emission control catalyst 20 by permanently deteriorating caused degradation, then, In step S77, using such mapping graph as shown in Figure 17 and Figure 18, the degradation caused by S poisoning deteriorations, knot are calculated Beam control processing procedure sequence.
Figure 24 is the sulphur ingredient containing ratio presumption control for indicating to estimate the sulphur ingredient containing ratio into the fuel that combustion chamber 5 supplies The flow chart of the control program of system.The control program of diagram is spaced execution at regular intervals.
First, in step S81, whether judgement presumption mark F becomes for ON.Presumption mark F is in sulphur ingredient containing ratio Presumption in be set as ON, other than it when be set as the mark of OFF.In step S81, it is determined as that being not already sulphur ingredient contains During the presumption of rate, in the case that presumption mark F is OFF, step S82 is entered.
In step S82, determines whether to perform sulphur disengaging processing, in step S83, determine whether to have carried out to fuel The fuel of case supplies.The detection supplied to the fuel of fuel tank, carries out in the following manner:For example, by detection fuel tank The fuel quantity that detects of sensor of fuel quantity increase, alternatively, being detected by the cover sensor of the opening and closing of detection fuel tank cap It is opened to lid.It is judged to being not carried out sulphur disengaging processing in step S82, and is judged to not carrying out in step S83 When being supplied to the fuel of fuel tank, finishing control program.On the other hand, it is judged to performing sulphur disengaging processing in step S82 In the case of or in the case of be judged to supply to the fuel of fuel tank in step S83, enter step S84. In step S84, presumption mark F, which is set, is set as ON, and time counter T is reset to 0.
When presumption mark F, which is set, is set as ON, in next control program, it is determined as presumption mark in step S81 Will F, which is set, has been set as ON, enters step S85.In step S85, time counter T adds 1 obtained value by as new The value of time counter T.Then, in a step s 86, caused by what acquirement calculated in the step S77 of Figure 23 is deteriorated by S poisonings Degradation.
Then, in step S87, judge whether the value of the time counter T calculated in step S85 is preset A reference value Tref or more.In the case of being determined as that the value of time counter T is less than a reference value Tref in step S87, terminate control Processing procedure sequence.On the other hand, in the case of being determined as value Tref or more on the basis of the value of time counter T in step S87, enter To step S88.
In step S88, the variable quantity of degradation caused by S poisoning deteriorations that presumption mark is set as after ON is calculated Divided by be worth obtained from the time corresponding with a reference value Tref of time counter, be used as per unit time be poisoned by S it is bad The change rate of degradation caused by changing.Then, in step S89, based on calculated in step S88 per unit time by The change rate of degradation caused by S poisoning deteriorations, to calculate the sulphur ingredient containing ratio in fuel.Then, in step S90, Presumption mark F is reset to OFF, finishing control program.
Furthermore in above-mentioned whole embodiment, controls, target air-fuel ratio is handed over as basic air-fuel ratio Alternately it is set as the control of dense setting air-fuel ratio and dilute setting air-fuel ratio repeatedly.But such control must be not necessarily carried out, If by target air-fuel ratio alternately be set to dense setting air-fuel ratio and dilute setting air-fuel ratio at least respectively once, can not also be anti- Multiple setting.

Claims (9)

1. a kind of emission-control equipment of internal combustion engine, has:
The exhaust channel in internal combustion engine, and catalyst-loaded noble metal is arranged in exhaust emission control catalyst;
NOx sensor, is arranged in the exhaust emission control catalyst or the flow direction of exhaust gases downstream of the exhaust emission control catalyst The exhaust channel of side;
Air-fuel ratio sensor, the exhaust being arranged in the flow direction of exhaust gases downstream side of the exhaust emission control catalyst are logical Road;With
Control device controls the target air-fuel ratio of the exhaust flowed into the exhaust emission control catalyst, and is based on the NOx Sensor exports to estimate the state of the exhaust emission control catalyst,
The target air-fuel ratio is alternately set as than the dense air-fuel ratio of richer and more empty than theoretical by the control device Combustion becomes than dilute dilute air-fuel ratio, also, in the air-fuel ratio of the exhaust detected from the air-fuel ratio sensor than theoretical air-fuel When than below dense dense judgement air-fuel ratio, the switching from dense air-fuel ratio to dilute air-fuel ratio of the target air-fuel ratio is carried out,
The control device executes the presumption control of the 1st degradation, in the 1st degradation presumption control, is not based on The output of the NOx sensor when air-fuel ratio of the exhaust flowed into the exhaust emission control catalyst is dilute air-fuel ratio, but The output of NOx sensor when air-fuel ratio based on the exhaust flowed into the exhaust emission control catalyst is dense air-fuel ratio, Come estimate with catalyst noble metal sintering the exhaust emission control catalyst the deterioration that can not restore degree.
2. the emission-control equipment of internal combustion engine according to claim 1,
The control device carries out the exception of the exhaust emission control catalyst based on the degree of the deterioration that can not restore Diagnosis, also, carry out the exhaust only when the air-fuel ratio of the exhaust flowed into the exhaust emission control catalyst is dense air-fuel ratio Change catalyst abnormity diagnosis, and the air-fuel ratio of the exhaust flowed into the exhaust emission control catalyst for dilute air-fuel ratio when not into The abnormity diagnosis of the row exhaust emission control catalyst.
3. the emission-control equipment of internal combustion engine according to claim 1 or 2,
The control device, in the 1st degradation presumption control, based on being switched to dense sky from by the target air-fuel ratio Combustion is dense sky compared with the air-fuel ratio of the exhaust flowed into the exhaust emission control catalyst until being switched to dilute air-fuel ratio The output of the NOx sensor during the center of switching timing in firing than during, leaving target air-fuel ratio, to push away The degree of the deterioration that can not restore of the fixed exhaust emission control catalyst.
4. according to the emission-control equipment of any one of them internal combustion engine of claims 1 to 3,
The control device executes the presumption control of the 2nd degradation not against the output of the NOx sensor, the described 2nd In degradation presumption control, presumption includes the sulfur poisoning institute of the deterioration and the exhaust emission control catalyst that can not restore Total degradation of the exhaust emission control catalyst of the caused deterioration that can restore,
The control device based on the total degradation deduced by the 2nd degradation is estimated and controlled and passes through institute The degree of the deterioration that can not restore stated the 1st degradation presumption control and deduced, to estimate the exhaust gas purification catalysis The degree of the deterioration that can restore of agent.
5. the emission-control equipment of internal combustion engine according to claim 3,
The control device executes the presumption control of the 2nd degradation not against the output of the NOx sensor, the described 2nd In degradation presumption control, presumption includes the sulfur poisoning institute of the deterioration and the exhaust emission control catalyst that can not restore Total degradation of the exhaust emission control catalyst of the caused deterioration that can restore,
The control device, based on the deterioration that can not restore deduced by the 1st degradation is estimated and controlled Degree sets poisoning a reference value so that and the degree of the deterioration that can not restore the big, a reference value of being poisoned is bigger, if The total degradation deduced by the 2nd degradation is estimated and controlled becomes the poisoning a reference value or more, then judges For the exhaust emission control catalyst sulfur poisoning.
6. the emission-control equipment of internal combustion engine according to claim 4 or 5,
It is also equipped with air-fuel ratio sensor, the row is set in the flow direction of exhaust gases downstream side of the exhaust emission control catalyst Gas access,
The control device, in the 2nd degradation presumption control, the output air-fuel ratio based on the air-fuel ratio sensor The dilute judgement air-fuel ratio for becoming diluter than chemically correct fuel is played from state more below than the dense judgement air-fuel ratio of richer The oxygen amount absorbed by the exhaust emission control catalyst or the parameter value or the sky that change corresponding to the oxygen amount until above Fire than the output air-fuel ratio of sensor from it is dilute judge air-fuel ratio more than state play until becoming dense judgement air-fuel ratio or less from The oxygen amount of the exhaust emission control catalyst release or the parameter value changed corresponding to the oxygen amount, are urged to estimate the exhaust gas purification Total degradation of agent.
7. the emission-control equipment of internal combustion engine according to claim 4 or 5,
It is also equipped with air-fuel ratio sensor, the row is set in the flow direction of exhaust gases downstream side of the exhaust emission control catalyst Gas access,
The control device becomes in the air-fuel ratio of the exhaust detected from the air-fuel ratio sensor than richer When below dense judgement air-fuel ratio, the switching from dense air-fuel ratio to dilute air-fuel ratio of the target air-fuel ratio is carried out,
The control device, in the 2nd degradation presumption control, based on being cut from dense air-fuel ratio in the target air-fuel ratio It is changed to the air-fuel ratio until output air-fuel ratio of the air-fuel ratio sensor reaches chemically correct fuel after dilute air-fuel ratio At least part of behavior of the output air-fuel ratio of sensor, to estimate total degradation of the exhaust emission control catalyst.
8. the emission-control equipment of internal combustion engine according to claim 4,
The control device executes containing ratio presumption control, in containing ratio presumption control, based on relative to time or suction The passage for entering the degree of the deterioration that can restore of the exhaust emission control catalyst of the variation of the accumulated value of air capacity, to estimate The sulphur containing ratio of the fuel supplied to the internal combustion engine.
9. the emission-control equipment of internal combustion engine according to claim 8,
The control device executes the sulphur disengaging processing for making to be detached from by the sulphur ingredient that the exhaust emission control catalyst absorbs,
The containing ratio presumption control is detached from after treatment in the sulphur and starts.
CN201810278352.1A 2017-03-31 2018-03-30 Exhaust gas purification device for internal combustion engine Expired - Fee Related CN108691612B (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112343695A (en) * 2019-08-08 2021-02-09 大众汽车股份公司 Method for heating a catalytic converter and exhaust gas aftertreatment system
CN114941580A (en) * 2021-02-15 2022-08-26 丰田自动车株式会社 Engine control device

Citations (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH09125937A (en) * 1995-11-07 1997-05-13 Tokyo Gas Co Ltd Method and device for judging deterioration of catalyst
CN1309746A (en) * 1998-07-17 2001-08-22 本田技研工业株式会社 Method for judging deteriration of emission gas control catalyst device
JP2002138821A (en) * 2000-11-02 2002-05-17 Mitsubishi Motors Corp Exhaust emission control device
US20040123585A1 (en) * 2002-12-20 2004-07-01 Toyota Jidosha Kabushiki Kaisha Exhaust emission control apparatus and method for internal combustion engine
CN1902386A (en) * 2004-01-06 2007-01-24 丰田自动车株式会社 Apparatus for evaluating deterioration condition of catalyst of internal combustion engine
CN101578434A (en) * 2007-03-13 2009-11-11 丰田自动车株式会社 Device for judging deterioration of catalyst
US20100199638A1 (en) * 2009-02-11 2010-08-12 Denso Corporation Apparatus for diagnosing deterioration of nox absorption-reduction catalyst
US20120016563A1 (en) * 2010-07-13 2012-01-19 Denso Corporation Emission deterioration informing device
US20160025026A1 (en) * 2014-07-23 2016-01-28 Toyota Jidosha Kabushiki Kaisha Exhaust gas purification apparatus for an internal combustion engine
US20160061084A1 (en) * 2013-01-29 2016-03-03 Toyota Jidosha Kabushiki Kaisha Control system of internal combustion engine
US20160363029A1 (en) * 2015-06-11 2016-12-15 Toyota Jidosha Kabushiki Kaisha Internal combustion engine
CN106337752A (en) * 2015-07-06 2017-01-18 丰田自动车株式会社 Exhaust Purification System Of Internal Combustion Engine

Patent Citations (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH09125937A (en) * 1995-11-07 1997-05-13 Tokyo Gas Co Ltd Method and device for judging deterioration of catalyst
CN1309746A (en) * 1998-07-17 2001-08-22 本田技研工业株式会社 Method for judging deteriration of emission gas control catalyst device
JP2002138821A (en) * 2000-11-02 2002-05-17 Mitsubishi Motors Corp Exhaust emission control device
US20040123585A1 (en) * 2002-12-20 2004-07-01 Toyota Jidosha Kabushiki Kaisha Exhaust emission control apparatus and method for internal combustion engine
CN1902386A (en) * 2004-01-06 2007-01-24 丰田自动车株式会社 Apparatus for evaluating deterioration condition of catalyst of internal combustion engine
CN101578434A (en) * 2007-03-13 2009-11-11 丰田自动车株式会社 Device for judging deterioration of catalyst
US20100199638A1 (en) * 2009-02-11 2010-08-12 Denso Corporation Apparatus for diagnosing deterioration of nox absorption-reduction catalyst
US20120016563A1 (en) * 2010-07-13 2012-01-19 Denso Corporation Emission deterioration informing device
US20160061084A1 (en) * 2013-01-29 2016-03-03 Toyota Jidosha Kabushiki Kaisha Control system of internal combustion engine
US20160025026A1 (en) * 2014-07-23 2016-01-28 Toyota Jidosha Kabushiki Kaisha Exhaust gas purification apparatus for an internal combustion engine
US20160363029A1 (en) * 2015-06-11 2016-12-15 Toyota Jidosha Kabushiki Kaisha Internal combustion engine
CN106337752A (en) * 2015-07-06 2017-01-18 丰田自动车株式会社 Exhaust Purification System Of Internal Combustion Engine

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112343695A (en) * 2019-08-08 2021-02-09 大众汽车股份公司 Method for heating a catalytic converter and exhaust gas aftertreatment system
US11261771B2 (en) 2019-08-08 2022-03-01 Volkswagen Aktiengesellschaft Method for heating a catalytic converter and exhaust gas aftertreatment system
CN114941580A (en) * 2021-02-15 2022-08-26 丰田自动车株式会社 Engine control device
CN114941580B (en) * 2021-02-15 2023-10-03 丰田自动车株式会社 Engine control device

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