WO2009059679A1 - Moteur à combustion interne à système d'échappement - Google Patents

Moteur à combustion interne à système d'échappement Download PDF

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Publication number
WO2009059679A1
WO2009059679A1 PCT/EP2008/008615 EP2008008615W WO2009059679A1 WO 2009059679 A1 WO2009059679 A1 WO 2009059679A1 EP 2008008615 W EP2008008615 W EP 2008008615W WO 2009059679 A1 WO2009059679 A1 WO 2009059679A1
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WO
WIPO (PCT)
Prior art keywords
exhaust gas
internal combustion
combustion engine
exhaust
heat exchanger
Prior art date
Application number
PCT/EP2008/008615
Other languages
German (de)
English (en)
Inventor
Brigitte Bandl-Konrad
Andreas Hertzberg
Bernd Krutzsch
Norbert Waldbuesser
Michel Weibel
Guenter Wenninger
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 WO2009059679A1 publication Critical patent/WO2009059679A1/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
    • F01N3/08—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
    • F01N3/2006—Periodically heating or cooling catalytic reactors, e.g. at cold starting or overheating
    • F01N3/2033—Periodically heating or cooling catalytic reactors, e.g. at cold starting or overheating using a fuel burner or introducing fuel into exhaust duct
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/92—Chemical or biological purification of waste gases of engine exhaust gases
    • B01D53/94—Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
    • B01D53/9445—Simultaneously removing carbon monoxide, hydrocarbons or nitrogen oxides making use of three-way catalysts [TWC] or four-way-catalysts [FWC]
    • B01D53/9454—Simultaneously removing carbon monoxide, hydrocarbons or nitrogen oxides making use of three-way catalysts [TWC] or four-way-catalysts [FWC] characterised by a specific device
    • 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
    • F01N3/0205—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust using heat exchangers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/24—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by constructional aspects of converting apparatus
    • F01N3/28—Construction of catalytic reactors
    • F01N3/2882—Catalytic reactors combined or associated with other devices, e.g. exhaust silencers or other exhaust purification devices
    • 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
    • F01N5/00—Exhaust or silencing apparatus combined or associated with devices profiting by exhaust energy
    • F01N5/02—Exhaust or silencing apparatus combined or associated with devices profiting by exhaust energy the devices using heat
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2240/00—Combination or association of two or more different exhaust treating devices, or of at least one such device with an auxiliary device, not covered by indexing codes F01N2230/00 or F01N2250/00, one of the devices being
    • F01N2240/02—Combination or association of two or more different exhaust treating devices, or of at least one such device with an auxiliary device, not covered by indexing codes F01N2230/00 or F01N2250/00, one of the devices being a heat exchanger
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2240/00—Combination or association of two or more different exhaust treating devices, or of at least one such device with an auxiliary device, not covered by indexing codes F01N2230/00 or F01N2250/00, one of the devices being
    • F01N2240/14—Combination or association of two or more different exhaust treating devices, or of at least one such device with an auxiliary device, not covered by indexing codes F01N2230/00 or F01N2250/00, one of the devices being a fuel burner
    • 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
    • F01N2250/00—Combinations of different methods of purification
    • F01N2250/04—Combinations of different methods of purification afterburning and catalytic conversion
    • 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

Definitions

  • the invention relates to an internal combustion engine with an exhaust system according to the preamble of claim 1.
  • an internal combustion engine with an exhaust system which comprises a formed as a diesel particulate filter exhaust gas purification unit, which is arranged in an exhaust pipe connected to the internal combustion engine.
  • the exhaust system further comprises a hot gas ⁇ generator, which can feed a hot gas at an upstream of the diesel particulate filter feed point into the exhaust pipe, so that mixed with the hot gas correspondingly heated exhaust gas of the internal combustion engine can be supplied to the diesel particulate filter.
  • the diesel particulate filter can be brought to a temperature required for thermal soot regeneration.
  • the object of the invention is to provide an internal combustion engine with a reliably operable exhaust system and improved thermal efficiency.
  • the inventive internal combustion engine comprises an exhaust system, which comprises a hot gas generator, wherein a hot ⁇ gas can feed at an upstream of the exhaust gas cleaning unit arranged feed point in the exhaust pipe, so that mixed with the hot gas exhaust of the internal combustion engine, the exhaust gas purification unit can be supplied.
  • a heat exchanger which can be flowed through by engine exhaust gas is provided, by means of which heat can be withdrawn from the exhaust gas of the internal combustion engine mixed with the hot gas and transferred to exhaust gas of the internal combustion engine upstream of the feed point.
  • the exhaust gas cleaning unit due to the supplied hot gas to a required for their safe operation, usually lying above the normal exhaust gas temperature operating temperature can be brought.
  • the exhaust gas at the hot gas supply point has an elevated temperature due to a previous heat absorption, and improved hot gas processing is enabled, which is particularly advantageous in hot gas generation by partial combustion of liquid fuel.
  • any unit can be used which is able to deliver a gas which exceeds a temperature usually prevailing on the input side of the exhaust gas purification unit and thus can raise the total exhaust gas temperature.
  • the delivered hot gas may be chemically inert or chemically heat-displaceable constituents.
  • the exhaust gas purification unit is preferably a unit for catalytic and / or filter technically effective emission control, which at least at times requires an operating temperature, which exceeds the normal exhaust gas temperature at the respective mounting location in the exhaust system over ⁇ .
  • the invention is particularly advantageously used for thermal management of a motor remote, arranged for example in the underbody area of the corresponding motor vehicle exhaust purification unit to operate them safely at a temperature level, which is not achieved due to the existing low exhaust gas temperatures without additional measures.
  • heat exchanger each suitable for the corresponding function component can be provided.
  • gas-gas heat exchangers in tube bundle, plate or foil construction, preferably according to the countercurrent principle, can be used.
  • the use of a heat pipe (heat-pipe) is also possible.
  • the exhaust gas emitted from the exhaust gas purification unit can be deprived of heat and transferred to exhaust gas flowing into the exhaust gas purification unit.
  • energy introduced into the exhaust gas upstream of the exhaust gas purification unit can be at least partially kept in the exhaust system, whereby the thermal efficiency is improved.
  • the internal combustion engine is designed as an internal combustion engine operated with a fuel consisting predominantly of methane and the exhaust gas purification unit is designed as an oxidation catalyst for the catalytic methane oxidation.
  • the exhaust gas purification unit is designed as an oxidation catalyst for the catalytic methane oxidation.
  • the removal of unburned methane residues in the exhaust gas occurs special importance. Due to the chemical stability of methane, catalytically assisted methane oxidation also requires comparatively high catalyst or exhaust gas temperatures. For a high conversion temperatures of over 350 0 C, typically even higher values of about 400 0 C are required.
  • the internal combustion engine according to the invention can be operated largely without methane emissions without appreciable efficiency losses.
  • the hot gas generator is designed for leaning of the engine exhaust gas. Under a leaning is understood here as usual an increase in the ratio of free oxygen to oxidizable constituents.
  • the hot gas generator supplies a hot gas with an excess of oxygen so that after mixing with the engine exhaust gas, an overall oxidizing exhaust gas composition results. In this way the efficiency of a catalytically assisted oxidation of constituents contained in the exhaust gas, in particular methane, is improved.
  • the exhaust gas cleaning unit is designed as a nitrogen oxide storage catalyst or as a particle filter and the hot gas generator is designed to enrich the engine exhaust gas.
  • a nitrogen oxide storage catalyst In a further embodiment of the invention, the exhaust gas cleaning unit is designed as a nitrogen oxide storage catalyst or as a particle filter and the hot gas generator is designed to enrich the engine exhaust gas.
  • the hot gas generator is designed to enrich the engine exhaust gas.
  • Such an embodiment is particularly advantageous for an internal combustion engine, in which the removal of nitrogen oxides or particles contained in the exhaust gas is of particular importance. This is the case in particular with diesel engines.
  • a nitrogen oxide storage catalyst With a nitrogen oxide storage catalyst, a reduction of nitrogen oxides can be particularly effective. However, especially for an occasionally necessary elimination of sulfur poisoning (desulfation) an increased operating temperature is required. The firing This engine makes this possible without significant loss of efficiency.
  • the invention provided enrichment of the engine exhaust gas by the hot gas generator is particularly advantageous.
  • the exhaust gas is enriched in its entirety with reducing constituents and a particularly effective desulfurization is made possible.
  • the enrichment by the hot gas generator can also be provided in such a way that overall an oxidizing effective exhaust gas is obtained, which, however, enriched with combustible constituents.
  • a heat exchanger downstream particle filter can be heated to a temperature required for Rußabbrand temperature.
  • the heat exchanger is designed as a countercurrent heat exchanger. This embodiment enables a particularly efficient heat exchange.
  • the heat exchanger of exhaust gas anströmbare catalytically active surface areas can additionally assume a catalytic function. It is advantageous to provide walls of gas-carrying channels of the heat exchanger with a catalytic coating which may be formed, for example, as an oxidation-catalytically active coating or as a coating with nitrogen oxide storage function. The coating may be provided in sections, for example on the inlet side and / or outlet side.
  • the heat exchanger itself can function as a catalytic converter therefore result catalytically coated surfaces anströmbarer ⁇ areas.
  • the heat exchanger for filtering particles from the exhaust gas is formed.
  • Gas leading channels of the heat exchanger for example, a contain porous material through which gas flowing into the heat exchanger is forced, whereby a filtering out of particles takes place.
  • the filter function can also be provided only partially, to keep pressure losses small.
  • the hot gas generator is designed as a burner for the at least partial combustion of a fuel used for internal combustion engine operation.
  • the combustion does not necessarily have to be associated with a flame phenomenon. Rather, a burner is to be understood as meaning any component which can convert a fuel under heat release and hot gas generation.
  • a lean or rich burner a catalytic or non-catalytic reactor designed to carry out a partial oxidation (POX reactor), a reformer for producing a fuel reformate and the like can be used to advantage.
  • POX reactor partial oxidation
  • FIG. 2b shows a detail of the heat exchanger according to Fig. 2a
  • Fig. 3 shows a second advantageous embodiment of an internal combustion engine with exhaust system according to the invention
  • Fig. 4 shows an advantageous embodiment of a part of the internal combustion engine exhaust system according to the invention.
  • 1 denotes an internal combustion engine to which an exhaust pipe 2 is connected, in which a first exhaust gas purification unit 5, a heat exchanger 7 and a second exhaust gas purification unit 6 are arranged in succession.
  • the units are in the operation of the internal combustion engine according to the direction of the arrow 10 of exhaust gas of the internal combustion engine 1 flows through.
  • a hot gas generator 3 is provided, which is designed such that it can generate a hot gas from a fuel and combustion air as required and feed it into the exhaust gas line 2 at a feed point 4 arranged upstream of the second exhaust gas purification unit 6.
  • Fuel and combustion air can be supplied to the hot gas generator 3 via supply lines 8 and 9 in adjustable amounts.
  • CNG compressed natural gas
  • This type of internal combustion engine is characterized by particular economy and low pollutant emissions, in particular low CO 2 emissions.
  • the removal of methane residues from the exhaust may be problematic.
  • the catalytic oxidation of methane requires high temperatures of typically more than 350 ° C. An at least temporary oxygen excess in the exhaust gas is advantageous.
  • a weak reducing set-gas may be provided in a composition ⁇ -range of typically 0.95 to 0.999 for catalytic oxidation of methane, wherein a proportion of free oxygen is advantageous.
  • Anord ⁇ voltage as shown in FIG. 1 an effective removal of hydrocarbons, in particular methane residues from the exhaust gas is made possible in a particularly advantageous manner, in particular in the said Bedin ⁇ conditions, as explained in more detail below.
  • the first exhaust gas cleaning unit 5 in the Formed like a conventional three-way catalyst.
  • the pollutants carbon monoxide (CO) and nitrogen oxide (NOx) by means of the first exhaust gas cleaning unit 5 can be effectively converted to harmless carbon dioxide (CO 2 ) and nitrogen (N 2 ).
  • the second exhaust gas purification unit 6 is designed as an optimized oxidation catalyst, especially with regard to a methane oxidation.
  • a catalytic coating containing more than 100 g / ft 3 of platinum group noble metals.
  • a noble metal coating in the range of about 200 g / ft 3 to 300 g / ft 3 , in particular in a preferably used under lean conditions Oxidationskataly- for methane.
  • a rhodium-free coating has proved to be advantageous.
  • a high palladium content of more than 250 g / ft 3 is preferred. Trains t. It is particularly preferred if at the same time a low proportion of platinum and / or rhodium is used in relation to palladium. A ratio of platinum and / or rhodium to palladium of from 1:20 to 1:35 is advantageous. The use of a platinum-free methane oxidation catalyst with a high palladium content is likewise advantageous.
  • lambda probes can be provided on the input side and / or output side of the exhaust gas purification units 5 and 6 or before and / or after the feed point 4, with the aid of which an air-fuel ratio for operating the internal combustion engine and / or an exhaust gas ⁇ can be adjusted.
  • an effective oxidation of methane residues by the second exhaust gas cleaning unit 6 it is particularly advantageous to set an exhaust gas composition or an exhaust gas ⁇ such that an occupancy of the catalytically active centers of the catalytic coating with oxygen is avoided.
  • an adsorption of oxygen at the catalytic centers, in particular the noble metal centers inhibits the oxidation of methane.
  • the intensity of the inhibition is temperature-dependent with decreasing tendency as the temperature increases.
  • the setting is preferably carried out with the aid of an input side of the exhaust gas purification unit 6 arranged lambda probe.
  • the adjustment of the exhaust gas ⁇ for exhaust gas flowing into the second exhaust gas purification unit can be achieved by a corresponding control of the engine combustion and / or the operation of the hot gas generator 3 can be achieved.
  • the setting of the exhaust gas ⁇ is preferably carried out as a function of the temperature of the second exhaust gas purification unit 6 or the exhaust gas inlet temperature, for which purpose expediently arranged temperature sensors are provided. It is preferable, at least in a temperature range from a light-off temperature for the methane oxidation to a catalyst-specifiable specifiable upper limit temperature, to set a weakly reducing exhaust gas ⁇ in the range from 0.96 to 0.999 at the beginning of the second exhaust gas purification unit 6. An exhaust ⁇ in the range of 0.97 to 0.98 is particularly preferred. In this case, a ⁇ oscillation approximately between 0.9 to 1.02 can be carried out with a time average in the range mentioned. It is particularly preferred to set an increasing ⁇ value with increasing temperature.
  • Typical values for the light-off temperature or the upper limit temperature are about 350 ° C. or about 450 ° C.
  • an oxygen desorption temperature of about 500 ° C. no adsorption of oxygen occurs in the case of the preferably used catalyst materials.
  • a purely oxidizing exhaust gas composition can be set at the beginning of the second exhaust gas purification unit 6.
  • An oxygen content of 1% to 5% is advantageous.
  • second exhaust gas purification unit 6 instead of a designed as a methane oxidation catalyst second exhaust gas purification unit 6 with a high palladium content and one having a comparatively low content of palladium, typically 100 g / ft J or less or be used to rhodium and / or palladium free methane oxidation catalyst.
  • a purely oxidizing exhaust gas composition with an exhaust gas ⁇ of more than 1.1, in particular more than 1.5, can be set.
  • temperatures typically more than 500 ° C.
  • An effective and economical temperature management is advantageous, especially with regard to low fuel consumption. Preferred measures for this will be discussed in more detail below.
  • the first exhaust gas cleaning unit 5 is formed in the manner of a nitrogen oxide storage catalyst.
  • the other components can be designed and operated analogously to the above explanations.
  • the nitrogen oxide storage catalyst removes the lean, i. oxidizing exhaust gas nitrogen oxides by storage.
  • a rich, i. Stored nitrogen oxides are released on the input side of the nitrogen oxide storage catalytic converter and largely converted to harmless nitrogen, as a result of which the nitrogen oxide storage catalytic converter is regenerated and is able to store nitrogen oxides again.
  • the adjustment of the rich exhaust gas composition required for regeneration can be achieved by a rich air-fueled engine operation.
  • An enrichment of the exhaust gas of the still lean operated internal combustion engine by supplying a reducing agent in the exhaust pipe 2 is also possible.
  • an unillustrated fuel injector can be provided upstream of the nitrogen oxide storage catalytic converter.
  • a supply of reducing hot gas by the hot gas generator 3 is also possible.
  • the second exhaust gas purification unit 6 As explained above, it is generally, but in particular in an engine designed as a CNG engine 1, to operate the second exhaust gas purification unit 6 above a temperature at which it can convert reducing exhaust gas constituents, in particular methane. reasonable
  • the aim is generally a rapid increase and a maintenance of temperatures above 350 0 C, in particular more than 450 0 C.
  • For rapid exhaust gas heating for example, after a cold start or in conjunction with a warm-up of the engine 1 and to increase a warm-running internal combustion engine low exhaust gas temperature level and / or to maintain an elevated exhaust gas temperature level is provided to feed from the hot gas generator 3 by fuel combustion produced hot gas at the feed point 4 in the exhaust pipe 2. This is preferably done in adjustable amounts for the fuel or air supply of the hot gas generator 3.
  • the hot gas generator can be put out of operation, if the internal combustion engine 1 exhaust gas is supplied above a predetermined temperature threshold, or a self-sufficient operation of the exhaust gas cleaning unit 6 above a temperature threshold applicable for this purpose is possible.
  • the hot gas generator 3 usually used for raising exhaust gas temperature can also be used for exhaust gas temperature reduction, if this is desired, for example, in high-load engine operation. In such a case, it is provided that only ambient air is fed into the exhaust pipe 2 from the hot gas generator 3. In this way, a comprehensive temperature management for the exhaust gas purification unit 6 is made possible, in which this can be operated in the desired target temperature range. Overheating over a predeterminable limit temperature or cooling below a lower limit temperature can thereby be avoided.
  • the hot gas generator 3 is operated with the provided for the operation of the internal combustion engine 1 fuel. Depending on whether in connection with an exhaust gas heating an enrichment of the exhaust gas is provided with reducing agent or with oxygen, the hot gas generator 3 is substoichiometric, ie with air shortage, or more than stoichiometrically, ie operated with excess air. A corresponding control or regulation is expediently carried out via volume regulating means in the supply lines 8, 9. These can be controlled by signals from sensors arranged in the exhaust line 2 for temperature and / or oxygen. For this purpose, a control unit is expediently provided, which is not shown in detail in Fig. 1. Preferably, the hot gas generator 3 is designed as a catalytic burner.
  • the efficiency of the arrangement shown in FIG. 1 is improved in particular by the fact that the hot exhaust gas emerging from the second exhaust gas purification unit 6 is at least partially supplied to the heat exchanger 7.
  • the preferably constructed according to the counterflow principle heat exchanger 7 withdraws from the second exhaust gas cleaning unit 6 effluent exhaust heat energy Q and transmits it to the exhaust gas supplied to it. In this way, the extent of the temperature increase to be applied by the hot gas generator 3 or the amount of heat to be supplied by the hot gas generator 3 decreases.
  • the heat exchanger 7 may be formed as a purely passive-acting, only heat-transmitting component. However, it may also be provided to additionally integrate in the heat exchanger 7 catalytically and / or filter technology effective means. For example, heat exchanger surfaces can be provided with a catalytic coating and / or a filter-effective section can be provided. In this case, an embodiment as a so-called autothermal reactor, in which balanced heat balance both heat-generating, exothermic and heat-consuming, endothermic chemical reactions can proceed, is particularly preferred. In the following, such an embodiment will be described in more detail with reference to FIGS. 2a and 2b. It goes without saying that on one or several of the exhaust gas cleaning functions of the heat exchanger 7 described below can also be dispensed with. It is also understood that the exhaust system variants discussed in connection with FIG. 1 and explained below are not limited to a specific embodiment of the heat exchanger.
  • the heat exchanger 7 shown schematically in Fig. 2a as a whole is designed as a counter-flow heat exchanger in plate design with heat exchanger surfaces serving as plates 71, which is shown in more detail in the Fig. 2b showing a detail.
  • the plates need not necessarily be flat, but may be wavy or otherwise shaped or folded.
  • a hot gas generator 3 is arranged, the hot gas according to the above explanations the engine exhaust gas at the arranged in the deflection region 78 feeding point 4 can perform.
  • the hot gas generator 3 is supplied via the supply line 8 with liquid fuel, for example with diesel fuel.
  • liquid fuel for example with diesel fuel.
  • the supplied fuel can be evaporated.
  • a catalytically assisted oxidation can take place.
  • the oxygen required for this purpose can be supplied to the hot gas generator 3 in the form of air or lean engine exhaust gas via the direction indicated here by the arrow 9 Feeding be supplied.
  • POX partial oxidation
  • the plates are at least partially provided with a catalytically active coating.
  • a catalytically active coating This can be arranged in the inflow passages 72 and / or in the outflow passages 73 and optionally differently, for example as an oxidation catalytic converter, nitrogen oxide storage catalytic converter, SCR catalytic converter or Denox catalytic converter.
  • a filter-effective region 74 is provided for filtering out particulate exhaust gas constituents. This can be arranged as shown in the inlet channels 72 at the end. An arrangement in the outflow channels 73 is also possible. It is preferred to arrange an oxidation-catalytically active region 77 upstream of the filter-effective region 74.
  • nitrogen monoxide contained in the exhaust gas can be oxidized to nitrogen dioxide, which enables oxidation of soot particles filtered out in the region 74 even at comparatively low temperatures of about 350 ° C.
  • nitrogen monoxide can be removed by a arranged in the outflow channels 73 coating 76 with a nitrogen oxide storage catalyst from the exhaust gas.
  • a further improvement of the nitrogen oxide reduction function can be achieved by a downstream coating 75 with an SCR catalyst, which in a reduction of ammonia formed in the nitrogen oxide storage catalyst 76 can be used for further reduction of nitrogen oxide.
  • FIGS. 2a and 2b A heat exchanger designed in accordance with FIGS. 2a and 2b is preferably used in an alternative arrangement shown schematically in FIG.
  • the arrangement according to FIG. 3 essentially corresponds to the arrangement shown in FIG. 1, so that only the essential differences are discussed.
  • FIG. 4 a further advantageous embodiment for a part of the engine exhaust system according to the invention is shown, wherein the internal combustion engine has not been included in the drawing.
  • the arrangement shown in Fig. 4 is preferably provided for installation in the engine exhaust system in the underfloor region of the corresponding vehicle.
  • the arrangement is characterized by a particularly compact design and a particularly high thermal look efficiency. This is achieved, in particular, by arranging the exhaust gas inlet and exhaust gas outlet connection of the second exhaust gas purification unit 6 closely adjacent to one and the same end thereof and in each case via a short line guide to the heat exchanger 7.
  • the feed point 4 for hot gas supplied by the hot gas generator 3 is arranged in an exhaust pipe part connecting the heat exchanger 7 to the second exhaust gas purification unit 6, via which exhaust gas to be cleaned is supplied to the second exhaust gas purification unit 6.
  • the second exhaust gas purification unit 6 has a catalyst or particle filter body 63, preferably in honeycomb construction, arranged in a housing 64.
  • the catalyst body may be formed as an oxidation three-way or nitrogen oxide storage catalyst. Exhaust gas flowing into the second exhaust gas purification unit 6 flows through the catalyst or particle filter body 63, is then deflected in a deflection region 61 in the housing 64 by 18o degrees and flows via an annular gap 62 surrounding the catalyst or particle filter body 63 to the exhaust gas outlet opening of the housing 64.
  • the exhaust systems discussed with reference to FIGS. 1 to 4 are advantageously usable in conjunction with an internal combustion engine which is operated predominantly lean with Otto, Diesel or CNG fuel. As explained, however, their use in stoichiometrically operated internal combustion engines of the type mentioned is also possible.
  • the exhaust gas purification units 5 and 6 and / or by a special design of the heat exchanger 7 an optimal adaptation to the respective type of internal combustion engine and application can be achieved. It is also possible and advantageous, in addition or alternatively more to provide exhaust gas purification components such as a particle ⁇ filter unit or an SCR catalyst, which may be upstream or downstream of the heat exchanger.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Health & Medical Sciences (AREA)
  • Toxicology (AREA)
  • Biomedical Technology (AREA)
  • Environmental & Geological Engineering (AREA)
  • Analytical Chemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Exhaust Gas After Treatment (AREA)

Abstract

L'invention concerne un système à combustion interne à système d'échappement. Le système d'échappement comprend une unité d'épuration des gaz d'échappement (6) et un générateur de gaz chaud (3) qui peut introduire un gaz chaud, en un point d'alimentation (4) disposé en amont de l'unité d'épuration des gaz d'échappement (6), dans un conduit (2) du système de gaz d'échappement, de telle façon que le gaz d'échappement, mélangé avec le gaz chaud, du moteur à combustion interne (1), soit amené dans l'unité d'épuration de gaz d'échappement (6). L'invention est caractérisée en ce qu'il est prévu un échangeur de chaleur (7) au moyen duquel de la chaleur est soutirée au gaz d'échappement mélangé avec le gaz chaud, et est transmise, en amont du point d'alimentation (4), au gaz d'échappement du moteur à combustion interne (1). L'invention s'applique particulièrement aux véhicules à moteurs alimentés en GNC (gaz naturel comprimé).
PCT/EP2008/008615 2007-11-08 2008-10-11 Moteur à combustion interne à système d'échappement WO2009059679A1 (fr)

Applications Claiming Priority (2)

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DE102007053130A DE102007053130A1 (de) 2007-11-08 2007-11-08 Brennkraftmaschine mit Abgassystem
DE102007053130.5 2007-11-08

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WO2009059679A1 true WO2009059679A1 (fr) 2009-05-14

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US8475754B2 (en) 2011-08-09 2013-07-02 Universitaet Stuttgart Institut fuer Chemische Apparatus and method for purifying exhaust gases for combustion engines
JP2017187035A (ja) * 2016-03-31 2017-10-12 マン・ディーゼル・アンド・ターボ・エスイー 排気ガス後処理システム及び内燃機関

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DE102010055548A1 (de) * 2010-12-22 2012-06-28 Deutz Ag Verbrennungskraftmaschine und Verfahren zum Betreiben derselben
EP2722503B1 (fr) * 2012-10-19 2021-10-13 Dinex Finland Oy Amplificateur thermique de gaz d'échappement
DE102012022712A1 (de) 2012-11-21 2014-05-22 Deutz Aktiengesellschaft Dieselpartikelfilter und Verfahren zur Regeneration desselben
WO2015197093A1 (fr) * 2014-06-27 2015-12-30 Volvo Truck Corporation Système échangeur de chaleur pour traitement d'un flux de gaz d'échappement dans un système de post-traitement de gaz d'échappement
DE102015001495A1 (de) 2015-02-05 2016-08-11 Man Diesel & Turbo Se Brennkraftmaschine und Verfahren zum Betreiben derselben
DE102016012457A1 (de) 2016-10-19 2017-04-27 Daimler Ag Antriebseinrichtung für ein Kraftfahrzeug, Abgasmodul für eine Verbrennungskraftmaschine, sowie Verfahren zum Betreiben einer solchen Antriebseinrichtung
DE102021134472A1 (de) 2021-12-23 2023-06-29 Tenneco Gmbh Vorrichtung zum Behandeln von Abgas II
WO2023117462A1 (fr) 2021-12-23 2023-06-29 Tenneco Gmbh Dispositif de traitement de gaz d'échappement ii

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EP0668437A1 (fr) * 1994-02-17 1995-08-23 Firma J. Eberspächer Méthode et dispositif pour posttraitement à brûleur thermique de gaz d'échappement de moteur
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DE1594710A1 (de) * 1965-10-28 1970-07-09 Von Linde Dipl Ing Robert Verfahren zur katalytischen Abgasbehandlung
DE2001933A1 (de) * 1970-01-16 1971-07-22 Uop Kavag Ges Fuer Luftreinhal Vorrichtung zur Durchfuehrung katalytischer Gasreaktionen
DE19503989A1 (de) * 1994-02-12 1995-08-17 Volkswagen Ag Abgasreinigungseinrichtung
EP0668437A1 (fr) * 1994-02-17 1995-08-23 Firma J. Eberspächer Méthode et dispositif pour posttraitement à brûleur thermique de gaz d'échappement de moteur
DE10105185A1 (de) * 2001-02-06 2002-08-14 Bosch Gmbh Robert Vorrichtung zur Abgasbehandlung mit einem Speicherkatalysator

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8475754B2 (en) 2011-08-09 2013-07-02 Universitaet Stuttgart Institut fuer Chemische Apparatus and method for purifying exhaust gases for combustion engines
JP2017187035A (ja) * 2016-03-31 2017-10-12 マン・ディーゼル・アンド・ターボ・エスイー 排気ガス後処理システム及び内燃機関

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