WO2017092839A1 - Procédé de post-traitement de gaz d'échappement et système d'échappement de gaz - Google Patents

Procédé de post-traitement de gaz d'échappement et système d'échappement de gaz Download PDF

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Publication number
WO2017092839A1
WO2017092839A1 PCT/EP2016/001673 EP2016001673W WO2017092839A1 WO 2017092839 A1 WO2017092839 A1 WO 2017092839A1 EP 2016001673 W EP2016001673 W EP 2016001673W WO 2017092839 A1 WO2017092839 A1 WO 2017092839A1
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WO
WIPO (PCT)
Prior art keywords
particulate filter
exhaust gas
reducing agent
amount
exhaust
Prior art date
Application number
PCT/EP2016/001673
Other languages
German (de)
English (en)
Inventor
Ortwin Balthes
Thomas Beckmann
Berthold Keppeler
Uwe KRONMÜLLER
Siegfried Mueller
Thorsten Woog
Original Assignee
Daimler Ag
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Daimler Ag filed Critical Daimler Ag
Publication of WO2017092839A1 publication Critical patent/WO2017092839A1/fr

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Classifications

    • 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
    • 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
    • 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
    • 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
    • F01N3/023—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 using means for regenerating the filters, e.g. by burning trapped particles
    • 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
    • F01N3/105—General auxiliary catalysts, e.g. upstream or downstream of the main catalyst
    • F01N3/106—Auxiliary oxidation 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
    • F01N3/206—Adding periodically or continuously substances to exhaust gases for promoting purification, e.g. catalytic material in liquid form, NOx reducing agents
    • 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
    • F01N3/2066—Selective catalytic reduction [SCR]
    • 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
    • F01N3/2066—Selective catalytic reduction [SCR]
    • F01N3/208—Control of selective catalytic reduction [SCR], e.g. dosing of reducing agent
    • 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
    • F01N9/002—Electrical control of exhaust gas treating apparatus of filter regeneration, e.g. detection of clogging
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2610/00—Adding substances to exhaust gases
    • F01N2610/02—Adding substances to exhaust gases the substance being ammonia or urea
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2610/00—Adding substances to exhaust gases
    • F01N2610/14—Arrangements for the supply of substances, e.g. conduits
    • F01N2610/1453—Sprayers or atomisers; Arrangement thereof in the exhaust apparatus
    • F01N2610/146—Control thereof, e.g. control of injectors or injection valves
    • 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
    • F01N2900/1606—Particle filter loading or soot amount
    • 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
    • F01N2900/1611—Particle filter ash amount
    • 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
    • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
    • Y02A50/20—Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/12—Improving ICE efficiencies
    • 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 exhaust gas aftertreatment of a vehicle.
  • the exhaust gas of an internal combustion engine of the vehicle by means of a
  • Particulate filter and by means of a downstream of the particulate filter, designed for the selective catalytic reduction of nitrogen oxides
  • Treated exhaust treatment device Furthermore, the invention relates to a trained for carrying out the method exhaust system for a vehicle.
  • Exhaust after-treatment device and a particulate filter are arranged comparatively close to the engine in the exhaust system, therefore, play an important role in order to meet these increased requirements can.
  • SCR selective catalytic reduction
  • PEMS portable emission measurement system, mobile emission measurement
  • the nitrogen oxides in the corresponding exhaust aftertreatment device are converted into nitrogen and water in a selective catalytic reduction reaction with ammonia.
  • the ammonia is often formed from urea, which in the form of an aqueous urea solution in the hot Exhaust gas is introduced. In the hot exhaust gas, the ammonia is formed from the urea.
  • a particle filter with integrated SCR coating must be thermally regenerated at regular intervals analogous to a conventional particle filter. During this regeneration, the soot stored on and in the filter wall is completely burned off. However, following regeneration, the filter does not show its full filtration efficiency. To achieve the full filtration performance, it is in fact necessary for a certain amount of soot to form on the filter wall first.
  • WO 20/144273 A1 describes a method for
  • the soot is not completely burned off. Rather, the regeneration is carried out so that the soot layer on the surface of the filter wall is at least partially retained.
  • a disadvantage here is the fact that such a particulate filter always has an increased flow resistance, so that the higher pressure loss of the filter to a reduction of the internal combustion engine for driving the
  • Vehicle provides achievable power. Moreover, such is one
  • Object of the present invention is therefore to provide an improved method of the type mentioned above and a corresponding exhaust system.
  • the exhaust gas of an internal combustion engine of the vehicle is treated by means of a particulate filter. Furthermore, the exhaust gas of the vehicle by means of a
  • Treated exhaust treatment device which is connected downstream of the particulate filter and which is designed for the selective catalytic reduction of nitrogen oxides.
  • an amount of a selective catalytic reduction reducing agent temporarily introduced into the exhaust gas upstream of the particulate filter is temporarily increased.
  • the particle emission of the exhaust system is lower than without introduction of the reducing agent into the exhaust gas.
  • the introduction of the reducing agent into the exhaust gas upstream of the particulate filter actively contributes to the reduction of the particle mass output. Accordingly, an improved method is provided.
  • the particle filter for a while, the amount of introduced into the exhaust gas upstream of the particulate filter reducing agent is increased. Furthermore, each time the particle filter is regenerated, the particle filter can be completely regenerated, ie the soot
  • Exhaust system compared to a not fully regenerated particulate filter. This is advantageous in view of the power available from the internal combustion engine of the vehicle for driving the vehicle.
  • Reducing agent is in particular based on an introduced during normal operation of the exhaust system amount, for example, based on the average before the
  • the invention is based on the finding that directly following a
  • Filtration efficiency shows. This is because initially only a depth filtration takes place, during which the particles are deposited there as they flow through the pores in the walls of the filter matrix in the filter matrix. Only with increasing loading of the particulate filter is formed on one of the surfaces of the channels, a filter cake. In the then onset surface filtration is a significant increase in
  • Reducing agent in particular by increasing the dosage of urea-water solution, the effect of such a dosage on the emissions of particles are used.
  • Particulate filter will be balanced and yet will be a lower overall
  • Reducing agent in a new car with brand new or brand new particulate filter is not significant in view of the anyway to reduce the nitrogen oxides in the exhaust gas to be introduced amount of reducing agent.
  • the introduction of the increased amount of the reducing agent into the exhaust gas may be stopped when a pressure loss between a first measuring point upstream of the particulate filter and a second measuring point downstream of the particulate filter reaches a predetermined value. So it can be about the counterpressure behavior of the
  • the time are detected, at which the depth filtration passes into the surface filtration. Additionally or alternatively, the time profile of the pressure loss can be monitored and the introduction of the increased amount can be terminated if the time course of the pressure loss corresponds to at least one predetermined criterion. Namely, the pressure loss is detected as a function of time and thus the time course of the Determined pressure loss, it is noted at the transition from the depth filtration to surface filtration kinking in a curve indicating the course of the pressure loss. Accordingly, it can be determined by monitoring the pressure loss or the differential pressure between the two measuring points in a particularly simple and reliable manner, when the particulate filter its full
  • the increase in the dosage can also be withdrawn time-controlled or fuel mass controlled. Accordingly, the introduction of the increased amount of the reducing agent in the exhaust gas can then be stopped as soon as a mass to after the regeneration of the particulate filter in the
  • Combustion engine introduced fuel has reached a predetermined value. Additionally or alternatively, the introduction of the increased amount of
  • Reducing agent are terminated in the exhaust gas after a predetermined period of time.
  • Such methods can be particularly simple to implement control technology or control technology.
  • Reducing agent are terminated in the exhaust gas, as soon as by means of a storage of soot into the particulate filter descriptive model, a predetermined state of
  • Particle filter was determined. It is therefore possible to model the condition of the particle filter by means of a soot emission model or filtration model. Such a method is particularly easy to carry out. Several of the abovementioned termination criteria can also be taken into account in order to determine particularly reliably the achievement of the full filtration efficiency of the particulate filter.
  • a stoichiometric ratio which relates the amount of reducing agent introduced into the exhaust gas to the emission of nitrogen oxides, is temporarily increased to a value of more than 1 following the regeneration.
  • reducing agent leaving the exhaust gas aftertreatment device can be converted by means of a downstream catalytic converter.
  • a so-called ammonia blocking catalyst can be provided downstream of the exhaust gas aftertreatment device designed for the selective catalytic reduction of nitrogen oxides, which converts or converts the ammonia into N 2 and H 2 O.
  • Reducing agent and the NOx raw emissions of the internal combustion engine can be increased, for example, by lowering an exhaust gas recirculation rate in the
  • Particle filter which leads to an improved separation efficiency of the particulate filter, can be achieved without the Pelleemssion after the particulate filter thereby deteriorates.
  • Particle filter efficiency achieved can thus be significantly shortened, resulting in an overall low particle emission of the vehicle.
  • Reducing agent is reduced, which after each regeneration of the
  • Particulate filter is introduced upstream of the particulate filter in the exhaust gas.
  • the operating strategy can be adapted with increasing transit time of the particulate filter.
  • Internal combustion engine or the vehicle and / or covered by the vehicle route can be considered. Also, more of these quantities or parameters may be used for determining the decrease in the amount of the reducing agent introduced into the exhaust gas to increase the reliability.
  • the appropriate sizes or parameters will be Usually determined at different locations of a control device such as an engine control unit and are thus available for the evaluation.
  • the amount of the reducing agent, which is introduced upstream of the particulate filter in the exhaust gas is temporarily increased, the amount of the reducing agent, which is introduced upstream of the particulate filter in the exhaust gas. If, for example due to a defect of the particulate filter increased particulate emissions is to be feared, up to a repair of the vehicle or until replacement of the defective particulate filter by the temporary introduction of the increased amount
  • Reducing agent of particle emissions can be reduced.
  • the presence of the defect of the particulate filter can in particular by a user of a vehicle
  • Internal combustion engine recirculated exhaust gas can be reduced.
  • the amount can be reduced to zero.
  • the exhaust gas recirculation can therefore be reduced or completely switched off.
  • this leads to a reduction of the particle raw emissions.
  • this increases the NO x raw emissions.
  • Reducing agent already in the SCR-coated particulate filter for the reduction of the nitrogen oxide content in the exhaust gas can provide. Preference is given to using a particle filter designed for the selective catalytic reduction of nitrogen oxides, which has a copper-containing zeolite as the catalytically active material.
  • the exhaust system according to the invention for a vehicle comprises a particle filter for treating exhaust gas of an internal combustion engine of the vehicle. Downstream of the particulate filter, an exhaust gas aftertreatment device is arranged, which is designed for the selective catalytic reduction of nitrogen oxides.
  • Control device is used to control a metering device, by means of which a reductant, which is provided for the selective catalytic reduction, can be introduced into the exhaust gas upstream of the particle filter.
  • the control device is designed to temporarily introduce an amount of the upstream of the particulate filter into the exhaust gas after a regeneration of the particulate filter
  • Fig. 2 shows a variant of the exhaust system according to Fig. 1, in which additionally a
  • Ammonia blocking catalyst is provided;
  • Fig. 4 is a graph showing the course of the pressure loss of the SCR-coated
  • Graphs is an area in which an elevated area is illustrated
  • Urea-water solution illustrates; and in another graph, the retraction of the increase in the metered amount of the urea-water solution with increasing ash charge of the SCR-coated particulate filter.
  • Fig. 1 shows schematically an exhaust system 10 of a vehicle, in particular a motor vehicle.
  • the exhaust gas from an internal combustion engine (not shown) of the vehicle is first supplied to an oxidation catalytic converter 12.
  • Oxidation catalyst 12 may be formed in particular as a diesel oxidation catalyst (DOC).
  • DOC diesel oxidation catalyst
  • the oxidation catalyst 12 may be an electrical
  • oxidation catalyst 12 Have heater to the oxidation catalyst 12 quickly to his To bring light-off, such as a cold start of the vehicle.
  • the oxidation catalyst 12 may also be provided a nitrogen oxide storage catalyst.
  • the SCR system 16 includes a particulate filter 18, which in the present case is designed as a particulate filter with an SCR coating. If the SCR-coated particulate filter 18 is designed as a diesel particulate filter, this is also referred to as SDPF for short.
  • the SCR system 16 further includes an SCR catalyst 20 disposed downstream of the particulate filter 18. Upstream of the particulate filter 18, a pressure sensor 22 is arranged in the exhaust pipe 14 and downstream of the particulate filter 18, a second pressure sensor 24.
  • an inlet 26 of a metering device 26 shown only partially here, via which a reducing agent for selective catalytic reduction (SCR selective catalytic reduction) can be introduced into the exhaust gas, which is supplied to the SCR system 16 becomes.
  • SCR selective catalytic reduction
  • the construction of the exhaust system 10 according to FIG. 2 essentially corresponds to the design of the exhaust system 10 shown in FIG. 1.
  • an ammonia blocking catalytic converter 28 is a component of the SCR system 16.
  • the ammonia blocking catalytic converter 28 is downstream of the SCR catalytic converter 20 arranged.
  • an exhaust gas recirculation system can be provided, in which a high-pressure exhaust gas recirculation and / or a low-pressure exhaust gas recirculation can be realized.
  • the exhaust gas upstream of the compressor of an exhaust gas turbocharger can be introduced into an intake tract of the internal combustion engine (low-pressure exhaust gas recirculation) or downstream of the compressor (high-pressure exhaust gas recirculation).
  • urea-water solution in the exhaust gas immediately downstream of the oxidation catalyst 12 is located.
  • a reducing agent obtainable under the brand name AdBlue® can be used as the urea solution.
  • the position of the metering device 26 for the urea-water solution results upstream of the particle filter 18 shows a relationship between the emission of particulate matter (PM) and the dosing amount. This will be illustrated with reference to FIG. 3.
  • the ordinate 32 indicates the particle mass emitted by the vehicle into the environment in milligrams per kilometer.
  • Two columns 34, 36 illustrate the particulate mass emissions detected at an exhaust system 10 outlet during a first drive cycle.
  • the driving cycle illustrated by pillars 34, 36 are the results of three extra Urban Driving Cycles (EUDCs), three of the extra-urban driving cycles used to pre-condition the new European Driving Cycle (NEDC).
  • EUDCs Extra Urban Driving Cycles
  • NEDC new European Driving Cycle
  • the first column 34 illustrates the particulate mass emission without metering the urea-water solution upstream of the particulate filter 18
  • the second column 36 the particulate emission at a dosage of urea-water solution. Accordingly, it can be seen that by introducing the urea-water solution upstream of the particulate filter 18, the particulate emissions can be reduced.
  • Particulate filter 18 does not yet have its full filtration efficiency. First, namely, only a depth filtration takes place in the particulate filter 18, in which the particles in the
  • the amount of urea-water solution introduced into the exhaust gas by means of the metering device 26 is increased in the present case.
  • the effect of dosing the urea-water solution on particle mass emission is utilized to compensate for the transiently lower filtration efficiency of the particulate filter 18. So can be very low Particle emissions in all operating conditions of the exhaust system 10 and the internal combustion engine of the vehicle can be achieved.
  • a control device 42 is presently provided (compare FIGS. 1 and 2).
  • the ordinate 46 indicates the differential pressure or pressure drop AP S DPF of the particle filter 18 in millibars.
  • the soot load of the particulate filter 18 in grams per liter is indicated on an abscissa 48.
  • a line 50 in the graph 44 illustrates that through the
  • a curve 52 describes the increase of the pressure loss AP S DPF- In a first section 54 of the curve 52, a depth filtration takes place, during which the soot is retained in the substrate. Here, the increase in pressure loss is comparatively steep.
  • a second section 56 illustrates a transition region, ie a transition of the curve 52 from
  • Section 54 which illustrates the depth filtration
  • section 58 which illustrates the surface filtration, so the filtration through a filter cake or soot cake.
  • Section 58 again bends curve 52, so curve 52 becomes even flatter.
  • the time can be detected in which the depth filtration passes into the surface filtration.
  • the temporary increase in the amount of the reducing agent introduced into the exhaust gas may be stopped or stopped when the filtration efficiency has reached a predetermined threshold.
  • the corresponding defined or predetermined time can be determined via a model which incorporates soot in the
  • Particle filter 18 describes, and which can be based on the first steeply rising and then increasingly flatter curve 68 shown in Fig. 5.
  • Excess reducing agent can be present in the SCR catalyst 20 and in the
  • Ammonia blocking catalyst 28 are converted to N 2 .
  • the operating strategy of the exhaust system 10 is adjusted with increasing transit time of the particulate filter 18. Because with increasing duration of use of the particulate filter 18, the ash storage in the filter wall of the particulate filter 18 increases. Dies
  • Ash charge of the particulate filter 8 are gradually withdrawn. This will be illustrated with reference to FIG. 6.
  • a graph 70 shown in FIG. 6 the ordinate 72 plots the ratio ⁇ of the metered amount of ammonia relative to the NO x emission.
  • Another line 78 in FIG. 6 illustrates the reduced amount of the excessively added urea-water solution, which is introduced into the exhaust gas after each regeneration of the particulate filter 18, as the particle filter 18 is operated longer. In particular, in this case a gradual withdrawal of the introduced into the exhaust gas amount of urea-water solution may be provided.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Health & Medical Sciences (AREA)
  • Toxicology (AREA)
  • Materials Engineering (AREA)
  • Exhaust Gas After Treatment (AREA)
  • Processes For Solid Components From Exhaust (AREA)

Abstract

L'invention concerne un procédé de post-traitement de gaz d'échappement d'un véhicule dans lequel le gaz d'échappement d'un moteur à combustion interne du véhicule est traité au moyen d'un filtre à particules (18) et au moyen d'un dispositif de post-traitement de gaz d'échappement (20) monté en aval du filtre à particules (18) et conçu pour effectuer une réduction catalytique sélective des oxydes d'azote. Selon l'invention, après avoir effectué une régénération du filtre à particules (18), on augmente temporairement la quantité d'agent réducteur destiné à effectuer la réduction catalytique sélective qui est introduite dans le gaz d'échappement en amont du filtre à particules (18). En outre, l'invention concerne un système d'échappement de gaz (10) destiné à un véhicule.
PCT/EP2016/001673 2015-12-02 2016-10-10 Procédé de post-traitement de gaz d'échappement et système d'échappement de gaz WO2017092839A1 (fr)

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DE102015015634.9 2015-12-02
DE102015015634.9A DE102015015634A1 (de) 2015-12-02 2015-12-02 Verfahren zur Abgasnachbehandlung und Abgasanlage

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2019086333A1 (fr) * 2017-10-30 2019-05-09 Volkswagen Aktiengesellschaft Procédé pour faire fonctionner un système d'échappement

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102020104373B4 (de) 2020-02-19 2023-08-31 Volkswagen Aktiengesellschaft Verfahren zur Abgasnachbehandlung, Abgasnachbehandlungsanlage sowie Kraftfahrzeug

Citations (3)

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Publication number Priority date Publication date Assignee Title
US20110167805A1 (en) * 2010-08-17 2011-07-14 Ford Global Technologies, Llc Method for reducing urea deposits in an aftertreatment system
WO2012008962A1 (fr) * 2010-07-15 2012-01-19 International Engine Intellectual Property Company, Llc Procédé anti-colmatage pour le traitement de gaz d'échappement
WO2015144273A1 (fr) * 2014-03-26 2015-10-01 Mtu Friedrichshafen Gmbh Procédé pour faire fonctionner un moteur à combustion interne, appareil de commande et moteur à combustion interne

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2012008962A1 (fr) * 2010-07-15 2012-01-19 International Engine Intellectual Property Company, Llc Procédé anti-colmatage pour le traitement de gaz d'échappement
US20110167805A1 (en) * 2010-08-17 2011-07-14 Ford Global Technologies, Llc Method for reducing urea deposits in an aftertreatment system
WO2015144273A1 (fr) * 2014-03-26 2015-10-01 Mtu Friedrichshafen Gmbh Procédé pour faire fonctionner un moteur à combustion interne, appareil de commande et moteur à combustion interne

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2019086333A1 (fr) * 2017-10-30 2019-05-09 Volkswagen Aktiengesellschaft Procédé pour faire fonctionner un système d'échappement

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