US20120180455A1 - Method for diagnosing an exhaust gas post-treatment - Google Patents
Method for diagnosing an exhaust gas post-treatment Download PDFInfo
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- US20120180455A1 US20120180455A1 US13/350,482 US201213350482A US2012180455A1 US 20120180455 A1 US20120180455 A1 US 20120180455A1 US 201213350482 A US201213350482 A US 201213350482A US 2012180455 A1 US2012180455 A1 US 2012180455A1
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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
- F01N11/00—Monitoring or diagnostic devices for exhaust-gas treatment apparatus, e.g. for catalytic activity
- F01N11/002—Monitoring or diagnostic devices for exhaust-gas treatment apparatus, e.g. for catalytic activity the diagnostic devices measuring or estimating temperature or pressure in, or downstream of the exhaust apparatus
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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
- F01N3/02—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust
- F01N3/021—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters
- F01N3/033—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters in combination with other devices
- F01N3/035—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters in combination with other devices with catalytic reactors, e.g. catalysed diesel particulate filters
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- 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
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- 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
- F02D41/1439—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the position of the sensor
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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
- F01N2550/00—Monitoring or diagnosing the deterioration of exhaust systems
- F01N2550/02—Catalytic activity of catalytic converters
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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
- F01N2550/00—Monitoring or diagnosing the deterioration of exhaust systems
- F01N2550/04—Filtering activity of particulate filters
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- 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
- F02D2041/228—Warning displays
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- 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
- F02D41/024—Introducing corrections for particular conditions exterior to the engine in relation with the state of the exhaust gas treating apparatus to increase temperature of the exhaust gas treating apparatus
- F02D41/025—Introducing corrections for particular conditions exterior to the engine in relation with the state of the exhaust gas treating apparatus to increase temperature of the exhaust gas treating apparatus by changing the composition of the exhaust gas, e.g. for exothermic reaction on exhaust gas treating apparatus
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- 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
- F02D41/027—Introducing corrections for particular conditions exterior to the engine in relation with the state of the exhaust gas treating apparatus to purge or regenerate the exhaust gas treating apparatus
- F02D41/029—Introducing corrections for particular conditions exterior to the engine in relation with the state of the exhaust gas treating apparatus to purge or regenerate the exhaust gas treating apparatus the exhaust gas treating apparatus being a particulate filter
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- 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
- F02D41/1452—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 a COx content or concentration
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- 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
- F02D41/1454—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 oxygen content or concentration or the air-fuel ratio
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- 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
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- 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
- F02D41/30—Controlling fuel injection
- F02D41/38—Controlling fuel injection of the high pressure type
- F02D41/40—Controlling fuel injection of the high pressure type with means for controlling injection timing or duration
- F02D41/401—Controlling injection timing
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/10—Internal combustion engine [ICE] based vehicles
- Y02T10/40—Engine management systems
Definitions
- the invention relates to a method for the on-board diagnosis of an exhaust gas post-treatment device for a combustion engine, wherein the exhaust gas post-treatment device has means for converting an exhaust gas component and wherein sensor means are provided downstream of the exhaust gas post-treatment device.
- Carbon particle filters are also called Diesel particulate filters (DPF).
- DPF Diesel particulate filters
- the particle filter cannot absorb any further soot, it has to be cleaned by a regeneration.
- different measures are available, whereof one is, for example, to additionally heat the exhaust gas by corresponding measures, so that the soot burns-off in the filter with oxygen contained in the lean exhaust gas.
- This soot burning is mostly incomplete, i.e. products of an incomplete burning, for example carbon monoxide, are produced.
- the particle filter is catalytically coated, whereby the carbon monoxide is oxidised to a very large extent to carbon dioxide, so that the carbon monoxide behind the filter emission is very low during a regeneration phase of the particle filter.
- this catalytic layer ages within the particle filter, so that it becomes inactive and a conversion of the carbon monoxide, produced by the regeneration, is not ensured anymore.
- This ageing process of the catalytic coating and the, thus, increased carbon monoxide emission during the regeneration of the particle filter is in practice a not directly recognisable problem.
- DE 10 2007 009 873 A1 discloses a method for detecting the occurrence of cross sensitivities of an exhaust gas sensor.
- the method is used in Diesel engines, which have in their exhaust-system branch an oxidising catalyst, a particulate filter and a particle sensor. It is provided, to conclude a defect of the catalyst concerning its ability in converting a second exhaust gas component by means of operational or specifically carried-out variations of the concentration of this second exhaust gas component upstream of the catalyst. It should enable, to recognise the presence of non-converted exhaust gas components in the area of the exhaust gas sensor and if necessary to carry out a corresponding correction of the sensor signal.
- the object is solved by a method for the on-board diagnosis of an exhaust gas post-treatment device for a combustion engine, wherein the exhaust gas post-treatment device comprises means for converting an exhaust gas component and wherein sensor means, arranged downstream of the exhaust gas post-treatment device, are provided, wherein the exhaust gas component is acquired by the sensor means and that by means of the quantity of the detected exhaust gas component, the quality of the means for converting the exhaust gas component is determined, wherein a signal of the sensor means is transmitted to a system for the on-board diagnosis.
- a method is provided in an advantageous manner, in which the presence or the missing of the relevant exhaust gas component can be detected.
- an exhaust gas post-treatment device working efficiently, and with correspondingly effective means for converting the relevant exhaust gas component, which, if at all, is only present in very low concentrations, it can be determined, that the means for converting this exhaust gas component operate efficiently. If on the other hand a distinctly increased concentration of the relevant exhaust gas component is measured by the sensor means, this is an indication, that the means for converting the exhaust gas component are faultily operating or are defective. Especially, in this case, a comparison with a reference value, for example, of a correctly working exhaust gas post-treatment device can be provided, which is taken as reference. If the value is larger than the reference value, it can be determined that the means for converting the exhaust gas component are faulty.
- the exhaust gas post-treatment device comprises at least one carbon particle filter with a catalytic coating for converting the exhaust gas component, wherein a regeneration of the exhaust gas post-treatment device is carried out, during which the exhaust gas component is produced.
- a regeneration of the exhaust gas post-treatment device is carried out, during which the exhaust gas component is produced.
- the exhaust gas component is acquired over a time interval, which extends from a first point in time during the starting phase of the regeneration at least up to a second point in time during the regeneration, preferably, at the end of the regeneration.
- the first point in time coincides with the starting of the regeneration or can be after the start of the regeneration. If the first point in time coincides with the start of the regeneration, this has the advantage of a simple starting condition.
- the start of the regeneration is carried out by measures inside the engine like throttling, later injection timing, additional and/or later injection. Intentionally, non-combusted fuel amounts reach the oxidation catalyst.
- the exhaust gas temperature increases up to approximately 620° C. to 630° C. inside the same, however, only with some time delay to the start of the measures inside the engine. During this time interval, a breakthrough or a slippage of the exhaust gas component, not converted by the oxidation catalyst, can take place. Only after the oxidation catalyst has been heated up to an exhaust gas temperature of approximately 620° C. to 630° C., this exhaust gas component is converted. This can be designated as the end of the starting phase. The heated exhaust gas starts then the burning-off procedure of the carbon-particulates in the particle filter.
- the first point in time of the measurement can be later than the starting of the regeneration by means of the sensor means arranged downstream of the particle filter.
- the temperature of the exhaust gas behind the oxidation catalyst can be used as a release condition for the temporal determination of this point in time relative to the starting of the regeneration.
- the relevant exhaust gas component if it is already emitted by the combustion engine, but has not been converted by an oxidation catalyst arranged upstream, can already be detected concerning its concentration. This can be used at a later point in time as a correction factor.
- the exhaust gas component is carbon monoxide, which content is determined by the carbon monoxide sensor.
- carbon monoxide which content is determined by the carbon monoxide sensor.
- this is a product of the generally incomplete burning of the carbon-particulates during the regeneration phase.
- carbon monoxide oxidises to carbon dioxide.
- the carbon monoxide sensor it can directly be determined, how high the concentration of the exhaust gas component, carbon monoxide, is during a regeneration phase of the particle filter, i.e. how much carbon monoxide is not effectively converted to carbon dioxide.
- a signal of the sensor means is transmitted to a system of an on-board diagnosis (OBD).
- OBD on-board diagnosis
- the signal of the sensor means which are, preferably, formed as a carbon monoxide sensor, represents the quantity, the concentration or the amount of the non-converted exhaust gas component in the total exhaust gas flow behind the filter.
- the object is solved by a device for the on-board diagnosis of an exhaust gas post-treatment device for a combustion engine, wherein the exhaust gas post-treatment device comprises means for converting an exhaust gas component and wherein sensor means are provided, and the sensor means are arranged downstream of the exhaust gas post-treatment device to determine an incomplete conversion of the exhaust gas component by means of detecting the same, and wherein the sensor means are connected to a system for the on-board diagnosis.
- the exhaust gas post-treatment device has at least one carbon particle filter with a catalytic coating for converting the exhaust gas component.
- the function of filtering and the function of converting are combined in one component.
- the sensor means comprise a carbon monoxide sensor.
- the carbon monoxide sensor it can be directly determined, how high the concentration of the exhaust gas component carbon monoxide is during a regeneration phase of the particle filter, i.e. how much carbon monoxide was not effectively converted into carbon dioxide.
- the sensor means for measuring carbon monoxide are adapted from a lambda-sensor, a NOx-sensor or an electro-chemically operating sensor.
- the sensor means comprise a catalytic coating and a temperature sensor.
- the detection of the exhaust gas component carbon monoxide, as far as this is not converted because of a defective catalytic coating within the particle filter, such, that the carbon monoxide, which leaves the particle filter in a non-converted condition, is followingly converted in the catalytic coating of the sensor means, arranged behind, and, in this case, causes an increase in temperature, which is detected by the temperature sensor.
- the senor means are connected to a system for the on-board diagnosis (OBD).
- OBD on-board diagnosis
- FIG. 1 is a principal representation of an exhaust-system branch
- FIG. 2 a is a temperature gradient of a carbon particle filter with a phase of regeneration
- FIG. 2 b is the carbon monoxide emissions of a carbon particle filter with catalytic coating
- FIG. 2 c is the carbon monoxide emissions of a carbon particle filter without catalytic coating.
- FIG. 1 shows a principal representation of a common exhaust-system branch 6 with a combustion engine 1 , which operates, for example, according to the Diesel principle, and is, when seen in flow direction A, arranged downstream of an oxidation catalyst 2 , a carbon particle filter 3 and a carbon monoxide sensor 4 , which is connected to a control device 5 for monitoring the sensor signals.
- the combustion engine can also be a lean operated Otto-engine (petrol engine).
- the control device is at least part of a system for the on-board-diagnosis (OBD).
- OBD on-board-diagnosis
- the carbon particle filter 3 is provided with a catalytic coating on its inside, which is not shown in detail in FIG. 1 because of the principal representation.
- a possibility for the temperature measurement can be provided downstream of the oxidation catalyst 2 .
- a diagnosis of the oxidation catalyst 2 is achieved by evaluating a temperature gradient behind the catalyst, after emissions in the form of not-burnt-off hydrocarbon or carbon monoxide are fed upstream of the catalyst.
- FIG. 2 over the time, different temperature gradients of a carbon particle filter and of the emissions of carbon monoxide behind the filter are shown.
- FIG. 2 a shows a temperature gradient of a carbon particle filter across a specific time interval, within which by means of common measures a regeneration is started.
- a possible measure can be, to additionally heat the exhaust gas by corresponding internal engine operating conditions, so that the carbon-particulates burn-off in the filter with the oxygen contained in the lean exhaust gas.
- This phase of the regeneration R is visible in the temperature gradient of FIG. 2 by means of the temperature increase.
- FIG. 2 b shows the carbon monoxide emissions of a carbon particle filter provided with a catalytic coating. Directly after the beginning of the regeneration, the concentration K of carbon monoxide temporarily increases, until the catalytic coating is heated-up and the carbon monoxide is oxidised to carbon dioxide. Further in FIG. 2 b , the integral I of the carbon monoxide emissions is shown.
- FIG. 2 c the carbon monoxide emissions of a non-catalytic coated carbon particle filter are shown.
- a distinct increase of the concentration K of carbon monoxide is observed.
- the integral I it is shown, that a distinct larger total amount of carbon monoxide was emitted compared to a catalytic coated carbon particle filter ( FIG. 2 b ).
- the basic idea of the method and of the device according to the invention is based on the fact, that by means of a carbon monoxide sensor downstream of the filter, the concentration of carbon monoxide can be measured in the exhaust gas flow and that a catalytic coated carbon particle filter, which coating, however, is functionally ineffective because of ageing or other damaging influencing factors, will at least generally have the concentration gradient of carbon monoxide as shown in FIG. 2 c , during the regeneration R.
- the carbon monoxide sensor measures during the regeneration an increased concentration of carbon monoxide.
- a possible procedure during the carrying out of the method according to the invention consists of the steps:
- a control light (malfunction indicator light MIL) lights up for information purposes.
- the emergency operation of the combustion engine can be taken into account.
Abstract
Method for the on-board diagnosis of an exhaust gas post-treatment device for a combustion engine, wherein the exhaust gas post-treatment device has means for converting an exhaust gas component and wherein sensor means are provided downstream of the exhaust gas post-treatment device, wherein the exhaust gas component is acquired by the sensor means and that by means of the quantity of the acquired exhaust gas component the quality of the means for converting the exhaust gas component is derived, wherein a signal of the sensor means is transmitted to a system for the on-board diagnosis.
Description
- This application claims priority of German Patent Application No. 102011000153.0 filed on Jan. 14, 2011, which is incorporated herein in its entirety by reference.
- The invention relates to a method for the on-board diagnosis of an exhaust gas post-treatment device for a combustion engine, wherein the exhaust gas post-treatment device has means for converting an exhaust gas component and wherein sensor means are provided downstream of the exhaust gas post-treatment device.
- The State of the Art is, that a carbon particle filter stores soot in the so-called adsorption operation. Carbon particle filters are also called Diesel particulate filters (DPF). When the particle filter cannot absorb any further soot, it has to be cleaned by a regeneration. For this, different measures are available, whereof one is, for example, to additionally heat the exhaust gas by corresponding measures, so that the soot burns-off in the filter with oxygen contained in the lean exhaust gas. This soot burning is mostly incomplete, i.e. products of an incomplete burning, for example carbon monoxide, are produced. Furthermore, it belongs to the State of the Art, that the particle filter is catalytically coated, whereby the carbon monoxide is oxidised to a very large extent to carbon dioxide, so that the carbon monoxide behind the filter emission is very low during a regeneration phase of the particle filter. Problems arise from the fact, that this catalytic layer ages within the particle filter, so that it becomes inactive and a conversion of the carbon monoxide, produced by the regeneration, is not ensured anymore. This ageing process of the catalytic coating and the, thus, increased carbon monoxide emission during the regeneration of the particle filter is in practice a not directly recognisable problem.
- DE 10 2007 009 873 A1 discloses a method for detecting the occurrence of cross sensitivities of an exhaust gas sensor. The method is used in Diesel engines, which have in their exhaust-system branch an oxidising catalyst, a particulate filter and a particle sensor. It is provided, to conclude a defect of the catalyst concerning its ability in converting a second exhaust gas component by means of operational or specifically carried-out variations of the concentration of this second exhaust gas component upstream of the catalyst. It should enable, to recognise the presence of non-converted exhaust gas components in the area of the exhaust gas sensor and if necessary to carry out a corresponding correction of the sensor signal.
- It is object of the present invention to diagnose the effectiveness of the catalytic coating of particle filters.
- The object is solved by a method for the on-board diagnosis of an exhaust gas post-treatment device for a combustion engine, wherein the exhaust gas post-treatment device comprises means for converting an exhaust gas component and wherein sensor means, arranged downstream of the exhaust gas post-treatment device, are provided, wherein the exhaust gas component is acquired by the sensor means and that by means of the quantity of the detected exhaust gas component, the quality of the means for converting the exhaust gas component is determined, wherein a signal of the sensor means is transmitted to a system for the on-board diagnosis. Thus, a method is provided in an advantageous manner, in which the presence or the missing of the relevant exhaust gas component can be detected. In an exhaust gas post-treatment device, working efficiently, and with correspondingly effective means for converting the relevant exhaust gas component, which, if at all, is only present in very low concentrations, it can be determined, that the means for converting this exhaust gas component operate efficiently. If on the other hand a distinctly increased concentration of the relevant exhaust gas component is measured by the sensor means, this is an indication, that the means for converting the exhaust gas component are faultily operating or are defective. Especially, in this case, a comparison with a reference value, for example, of a correctly working exhaust gas post-treatment device can be provided, which is taken as reference. If the value is larger than the reference value, it can be determined that the means for converting the exhaust gas component are faulty.
- According to the invention it is provided, that the exhaust gas post-treatment device comprises at least one carbon particle filter with a catalytic coating for converting the exhaust gas component, wherein a regeneration of the exhaust gas post-treatment device is carried out, during which the exhaust gas component is produced. Of advantage is, that the function of filtering and the function of converting is combined into one component, which is available on the market in different configurations. It is also advantageous, that the carbon particle filter, which contains also the catalytic coating for converting the exhaust gas component, converts the exhaust gas components, produced during the regeneration phase.
- As individual method steps it can be provided, that the exhaust gas component is acquired over a time interval, which extends from a first point in time during the starting phase of the regeneration at least up to a second point in time during the regeneration, preferably, at the end of the regeneration. In this case, it can be provided, that the first point in time coincides with the starting of the regeneration or can be after the start of the regeneration. If the first point in time coincides with the start of the regeneration, this has the advantage of a simple starting condition. Generally, the start of the regeneration is carried out by measures inside the engine like throttling, later injection timing, additional and/or later injection. Intentionally, non-combusted fuel amounts reach the oxidation catalyst. Because of the thus forced reactions in the oxidation catalyst, the exhaust gas temperature increases up to approximately 620° C. to 630° C. inside the same, however, only with some time delay to the start of the measures inside the engine. During this time interval, a breakthrough or a slippage of the exhaust gas component, not converted by the oxidation catalyst, can take place. Only after the oxidation catalyst has been heated up to an exhaust gas temperature of approximately 620° C. to 630° C., this exhaust gas component is converted. This can be designated as the end of the starting phase. The heated exhaust gas starts then the burning-off procedure of the carbon-particulates in the particle filter. To not determine this portion of the non-converted exhaust gas component, the first point in time of the measurement can be later than the starting of the regeneration by means of the sensor means arranged downstream of the particle filter. As a release condition for the temporal determination of this point in time relative to the starting of the regeneration, the temperature of the exhaust gas behind the oxidation catalyst can be used.
- As the first point in time is set before the start of the regeneration, it is ensured, that the relevant exhaust gas component, if it is already emitted by the combustion engine, but has not been converted by an oxidation catalyst arranged upstream, can already be detected concerning its concentration. This can be used at a later point in time as a correction factor.
- In detail it is provided, that the exhaust gas component is carbon monoxide, which content is determined by the carbon monoxide sensor. As already explained above, this is a product of the generally incomplete burning of the carbon-particulates during the regeneration phase. In a functionally effective catalytic coating of the particle filter, carbon monoxide oxidises to carbon dioxide. By the carbon monoxide sensor it can directly be determined, how high the concentration of the exhaust gas component, carbon monoxide, is during a regeneration phase of the particle filter, i.e. how much carbon monoxide is not effectively converted to carbon dioxide.
- Preferably, it is provided, that, when exceeding a threshold of the quantity of the exhaust gas component, a signal of the sensor means is transmitted to a system of an on-board diagnosis (OBD). Preferably, the signal of the sensor means, which are, preferably, formed as a carbon monoxide sensor, represents the quantity, the concentration or the amount of the non-converted exhaust gas component in the total exhaust gas flow behind the filter. Thus, it is ensured in an advantageous manner, that during the operation control lights—malfunction indicator light MIL—can then be activated and the causing malfunction can be recorded.
- Furthermore, the object is solved by a device for the on-board diagnosis of an exhaust gas post-treatment device for a combustion engine, wherein the exhaust gas post-treatment device comprises means for converting an exhaust gas component and wherein sensor means are provided, and the sensor means are arranged downstream of the exhaust gas post-treatment device to determine an incomplete conversion of the exhaust gas component by means of detecting the same, and wherein the sensor means are connected to a system for the on-board diagnosis.
- According to the invention it is provided, that the exhaust gas post-treatment device has at least one carbon particle filter with a catalytic coating for converting the exhaust gas component. In this case, it is advantageous, that the function of filtering and the function of converting are combined in one component.
- In a preferred embodiment it is provided, that the sensor means comprise a carbon monoxide sensor. By means of the carbon monoxide sensor, it can be directly determined, how high the concentration of the exhaust gas component carbon monoxide is during a regeneration phase of the particle filter, i.e. how much carbon monoxide was not effectively converted into carbon dioxide.
- Alternatively, it can be provided, that the sensor means for measuring carbon monoxide are adapted from a lambda-sensor, a NOx-sensor or an electro-chemically operating sensor. Thus, the advantage is achieved, that these sensors are available on the market in many types, as they have already been used in the surroundings of an exhaust-system branch.
- As a further alternative, it can be provided, that the sensor means comprise a catalytic coating and a temperature sensor. In this embodiment the detection of the exhaust gas component carbon monoxide, as far as this is not converted because of a defective catalytic coating within the particle filter, such, that the carbon monoxide, which leaves the particle filter in a non-converted condition, is followingly converted in the catalytic coating of the sensor means, arranged behind, and, in this case, causes an increase in temperature, which is detected by the temperature sensor.
- For each of the embodiments it can be provided, that the sensor means are connected to a system for the on-board diagnosis (OBD). Thus, it is ensured in an advantageous manner, that during the operation, control lights—malfunction indicator light MIL—can then be activated and the causing malfunction can be recorded.
- In the following, the method according to the invention and the device for diagnosing the ability of converting of a carbon particles filter by means of carbon monoxide measurement is described by using the figures. It shows:
-
FIG. 1 is a principal representation of an exhaust-system branch; -
FIG. 2 a is a temperature gradient of a carbon particle filter with a phase of regeneration; -
FIG. 2 b is the carbon monoxide emissions of a carbon particle filter with catalytic coating; and -
FIG. 2 c is the carbon monoxide emissions of a carbon particle filter without catalytic coating. -
FIG. 1 shows a principal representation of a common exhaust-system branch 6 with acombustion engine 1, which operates, for example, according to the Diesel principle, and is, when seen in flow direction A, arranged downstream of anoxidation catalyst 2, a carbon particle filter 3 and acarbon monoxide sensor 4, which is connected to acontrol device 5 for monitoring the sensor signals. The combustion engine can also be a lean operated Otto-engine (petrol engine). In the manner, which is not described in more detail, but generally known, the control device is at least part of a system for the on-board-diagnosis (OBD). The carbon particle filter 3 is provided with a catalytic coating on its inside, which is not shown in detail inFIG. 1 because of the principal representation. - Furthermore, a possibility for the temperature measurement can be provided downstream of the
oxidation catalyst 2. Thus, a diagnosis of theoxidation catalyst 2 is achieved by evaluating a temperature gradient behind the catalyst, after emissions in the form of not-burnt-off hydrocarbon or carbon monoxide are fed upstream of the catalyst. - In
FIG. 2 over the time, different temperature gradients of a carbon particle filter and of the emissions of carbon monoxide behind the filter are shown. In detail,FIG. 2 a shows a temperature gradient of a carbon particle filter across a specific time interval, within which by means of common measures a regeneration is started. A possible measure can be, to additionally heat the exhaust gas by corresponding internal engine operating conditions, so that the carbon-particulates burn-off in the filter with the oxygen contained in the lean exhaust gas. This phase of the regeneration R is visible in the temperature gradient ofFIG. 2 by means of the temperature increase. -
FIG. 2 b shows the carbon monoxide emissions of a carbon particle filter provided with a catalytic coating. Directly after the beginning of the regeneration, the concentration K of carbon monoxide temporarily increases, until the catalytic coating is heated-up and the carbon monoxide is oxidised to carbon dioxide. Further inFIG. 2 b, the integral I of the carbon monoxide emissions is shown. - For comparison, in
FIG. 2 c the carbon monoxide emissions of a non-catalytic coated carbon particle filter are shown. In such a filter, during the regeneration R, a distinct increase of the concentration K of carbon monoxide is observed. By means of the integral I, it is shown, that a distinct larger total amount of carbon monoxide was emitted compared to a catalytic coated carbon particle filter (FIG. 2 b). - The basic idea of the method and of the device according to the invention is based on the fact, that by means of a carbon monoxide sensor downstream of the filter, the concentration of carbon monoxide can be measured in the exhaust gas flow and that a catalytic coated carbon particle filter, which coating, however, is functionally ineffective because of ageing or other damaging influencing factors, will at least generally have the concentration gradient of carbon monoxide as shown in
FIG. 2 c, during the regeneration R. In this case, the carbon monoxide sensor measures during the regeneration an increased concentration of carbon monoxide. When it can be excluded, that because of other malfunctions in the exhaust-system branch 6 upstream of the carbon particle filter 3, an increased concentration of carbon monoxide is produced, it can be diagnosed, that the catalytic coating of the carbon particle filter is damaged, so that it cannot convert carbon monoxide produced during the regeneration R to carbon dioxide, and the carbon monoxide is emitted in a non-converted manner. - A possible procedure during the carrying out of the method according to the invention consists of the steps:
-
- starting the regeneration by common measures,
- measuring the emission of carbon monoxide,
- integrating the emission of carbon monoxide, preferably, up to the end of the regeneration,
- comparing the integral of the emissions of carbon monoxide with a reference value of a reference filter, which, preferably, is a filter, fully functioning concerning the conversion, for example with a conversion rate of 99%,
- starting the measures in dependency of the value comparison, wherein a faulty coating can be determined, when the measured value is larger than the reference value.
- As a starting measure, initially a control light (malfunction indicator light MIL) lights up for information purposes. As a further measure, the emergency operation of the combustion engine can be taken into account.
- By means of the described method, it is possible to detect an ageing of the catalytic coating of a carbon particle filter. When the catalytic coating is aged, allows this again conclusions, that also the conversion of carbon monoxide (CO) and of unburnt hydrocarbon (HC) at cold temperatures, like after the cold start of the engine, can be reduced. Because of this, it is also indirectly possible by means of the method according to the invention, to diagnose also the ability to convert CO and HC during the normal operation, to which also a cold start belongs.
- It is to be understood that various modifications are readily made to the embodiments disclosed herein without departing from the scope and spirit thereof. Accordingly, it is to be understood that the invention is not to be limited by the specific illustrated embodiment, but by the scope of the appended claims.
Claims (9)
1. A method for the on-board diagnosis of an exhaust gas post-treatment device for a combustion engine, comprising:
providing an exhaust gas post-treatment device, a means of converting an exhaust gas component and a sensor means arranged downstream of the exhaust gas post-treatment device, wherein the exhaust gas post-treatment device has at least one carbon particle filter with a catalytic coating for converting the exhaust gas component;
acquiring the exhaust gas component by the sensor means and determining the quantity of the acquired exhaust gas component;
determining the quality of the means for converting the exhaust gas component;
transmitting a signal of the sensor means to a system for on-board diagnosis; and
regenerating the carbon particle filter, during which the exhaust gas component is produced.
2. The method according to claim 1 , wherein the exhaust gas component is acquired during a time interval, which extends from a first point in time during the starting phase of the regeneration at least up to a second point in time during the regeneration.
3. The method according to claim 2 , wherein the first point in time coincides with the start of the regeneration or a time after the start of the regeneration.
4. The method according to claim 1 , wherein the exhaust gas component is carbon monoxide, which content is determined by a carbon monoxide sensor.
5. The method according to claim 1 , wherein, when exceeding a threshold value of the quantity of the exhaust gas component, a signal of the sensor means is transmitted to the system for the on-board diagnosis.
6. A device for on-board diagnosis of an exhaust gas post-treatment device for a combustion engine comprising an exhaust gas post-treatment device for converting an exhaust gas component and a sensor,
wherein the exhaust gas post-treatment device has at least one carbon particle filter with a catalytic coating for converting the exhaust gas component,
the sensor means is arranged downstream of the exhaust gas post-treatment device, to detect an incomplete conversion of the exhaust gas component during a regeneration of the carbon particle filter by detecting the same, and
the sensor is connected to a system for the on-board diagnosis.
7. The device according to claim 6 , wherein the sensor means has a carbon monoxide sensor.
8. The device according to claim 6 , wherein the sensor for measuring the carbon monoxide is adapted from a lambda-sensor, a NOx-sensor or an electro-chemically operating sensor.
9. The device according to claim 6 , wherein the sensor has a catalytic coating and a temperature sensor.
Applications Claiming Priority (2)
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DE102011000153A DE102011000153A1 (en) | 2011-01-14 | 2011-01-14 | Method for the diagnosis of exhaust gas aftertreatment |
DE102011000153.0 | 2011-01-14 |
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US20120180455A1 true US20120180455A1 (en) | 2012-07-19 |
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US13/350,482 Abandoned US20120180455A1 (en) | 2011-01-14 | 2012-01-13 | Method for diagnosing an exhaust gas post-treatment |
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JP (1) | JP5967941B2 (en) |
DE (1) | DE102011000153A1 (en) |
Cited By (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US10287960B2 (en) | 2014-04-29 | 2019-05-14 | Mtu Friedrichshafen Gmbh | Method for detecting the aging of a heterogeneous catalytic converter, exhaust after-treatment system for an internal combustion engine, and internal combustion engine |
US20220186643A1 (en) * | 2020-12-14 | 2022-06-16 | Toyota Jidosha Kabushiki Kaisha | Exhaust purification system of internal combustion engine |
US11636870B2 (en) | 2020-08-20 | 2023-04-25 | Denso International America, Inc. | Smoking cessation systems and methods |
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Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE102015003126B4 (en) * | 2015-03-12 | 2020-03-19 | Daimler Ag | Method for diagnosing an exhaust system of a vehicle and exhaust system |
JP6394616B2 (en) * | 2016-01-22 | 2018-09-26 | トヨタ自動車株式会社 | Exhaust gas purification device for internal combustion engine |
Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6502386B1 (en) * | 2000-08-02 | 2003-01-07 | Ford Global Technologies, Inc. | Catalyst monitoring in a diesel engine |
US6739176B2 (en) * | 2000-03-21 | 2004-05-25 | Dmc2 Degussa Metal Catalysts Cerdec Ag | Process for checking the operability of an exhaust gas purification catalyst |
US7100365B2 (en) * | 2003-07-31 | 2006-09-05 | Nissan Motor Co., Ltd. | Combustion control system of internal combustion engine |
US7204082B1 (en) * | 2005-12-09 | 2007-04-17 | Delphi Technologies, Inc. | System for combustion of reformate in an engine exhaust stream |
US20100005788A1 (en) * | 2008-07-14 | 2010-01-14 | Mcconnell Campbell R | Method For Regenerating A Diesel Particulate Filter |
US20120067026A1 (en) * | 2010-09-22 | 2012-03-22 | Gm Global Technology Operations, Inc. | Exhaust Gas Treatment System for an Internal Combustion Engine |
US8572952B2 (en) * | 2010-05-12 | 2013-11-05 | Ford Global Technologies, Llc | Diesel particulate filter control |
Family Cites Families (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE358925T1 (en) * | 1988-09-14 | 1991-04-11 | Seiko Co., Ltd., Kashiwa, Chiba, Jp | CO DETECTING CO BY CATALYTIC COMBUSTION. |
JPH1181994A (en) * | 1997-09-03 | 1999-03-26 | Nippon Soken Inc | Diagnosing device for catalyst for purifying exhaust gas from internal combustion engine |
JP2000337132A (en) * | 1999-05-27 | 2000-12-05 | Honda Motor Co Ltd | Exhaust emission control device for internal combustion engine |
US7031827B2 (en) * | 2003-04-11 | 2006-04-18 | Ford Global Technologies, Llc | Computer algorithm to estimate particulate filter regeneration rates |
DE102004048313A1 (en) * | 2004-10-05 | 2006-04-06 | Robert Bosch Gmbh | Exhaust system for an internal combustion engine, and method for operating such an exhaust system |
JP2008064004A (en) * | 2006-09-06 | 2008-03-21 | Toyota Motor Corp | Exhaust emission control system of internal combustion engine |
DE102007009873B4 (en) | 2007-03-01 | 2021-05-20 | Robert Bosch Gmbh | Method for detecting the occurrence of cross-sensitivities in an exhaust gas sensor |
DE102007059523B4 (en) * | 2007-12-11 | 2012-03-01 | Continental Automotive Gmbh | Method and device for diagnosing a particulate filter |
-
2011
- 2011-01-14 DE DE102011000153A patent/DE102011000153A1/en not_active Withdrawn
-
2012
- 2012-01-13 US US13/350,482 patent/US20120180455A1/en not_active Abandoned
- 2012-01-16 JP JP2012006244A patent/JP5967941B2/en not_active Expired - Fee Related
Patent Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6739176B2 (en) * | 2000-03-21 | 2004-05-25 | Dmc2 Degussa Metal Catalysts Cerdec Ag | Process for checking the operability of an exhaust gas purification catalyst |
US6502386B1 (en) * | 2000-08-02 | 2003-01-07 | Ford Global Technologies, Inc. | Catalyst monitoring in a diesel engine |
US7100365B2 (en) * | 2003-07-31 | 2006-09-05 | Nissan Motor Co., Ltd. | Combustion control system of internal combustion engine |
US7204082B1 (en) * | 2005-12-09 | 2007-04-17 | Delphi Technologies, Inc. | System for combustion of reformate in an engine exhaust stream |
US20100005788A1 (en) * | 2008-07-14 | 2010-01-14 | Mcconnell Campbell R | Method For Regenerating A Diesel Particulate Filter |
US8572952B2 (en) * | 2010-05-12 | 2013-11-05 | Ford Global Technologies, Llc | Diesel particulate filter control |
US20120067026A1 (en) * | 2010-09-22 | 2012-03-22 | Gm Global Technology Operations, Inc. | Exhaust Gas Treatment System for an Internal Combustion Engine |
Cited By (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US10287960B2 (en) | 2014-04-29 | 2019-05-14 | Mtu Friedrichshafen Gmbh | Method for detecting the aging of a heterogeneous catalytic converter, exhaust after-treatment system for an internal combustion engine, and internal combustion engine |
US11636870B2 (en) | 2020-08-20 | 2023-04-25 | Denso International America, Inc. | Smoking cessation systems and methods |
US11760170B2 (en) | 2020-08-20 | 2023-09-19 | Denso International America, Inc. | Olfaction sensor preservation systems and methods |
US11760169B2 (en) | 2020-08-20 | 2023-09-19 | Denso International America, Inc. | Particulate control systems and methods for olfaction sensors |
US11813926B2 (en) | 2020-08-20 | 2023-11-14 | Denso International America, Inc. | Binding agent and olfaction sensor |
US11828210B2 (en) | 2020-08-20 | 2023-11-28 | Denso International America, Inc. | Diagnostic systems and methods of vehicles using olfaction |
US11881093B2 (en) | 2020-08-20 | 2024-01-23 | Denso International America, Inc. | Systems and methods for identifying smoking in vehicles |
US11932080B2 (en) | 2020-08-20 | 2024-03-19 | Denso International America, Inc. | Diagnostic and recirculation control systems and methods |
US20220186643A1 (en) * | 2020-12-14 | 2022-06-16 | Toyota Jidosha Kabushiki Kaisha | Exhaust purification system of internal combustion engine |
Also Published As
Publication number | Publication date |
---|---|
DE102011000153A1 (en) | 2012-07-19 |
JP5967941B2 (en) | 2016-08-10 |
JP2012149645A (en) | 2012-08-09 |
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