Classifications

• • 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
  • F02D41/008—Controlling each cylinder individually
  • F02D41/0082—Controlling each cylinder individually per groups or banks
• • 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
  • F01N13/009—Exhaust or silencing apparatus characterised by constructional features 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
  • F01N13/00—Exhaust or silencing apparatus characterised by constructional features
  • F01N13/011—Exhaust or silencing apparatus characterised by constructional features having two or more purifying devices arranged in parallel
• • 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
  • F01N3/0807—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by using absorbents or adsorbents
  • F01N3/0814—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by using absorbents or adsorbents combined with catalytic converters, e.g. NOx absorption/storage reduction 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
  • F01N3/0807—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by using absorbents or adsorbents
  • F01N3/0828—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by using absorbents or adsorbents characterised by the absorbed or adsorbed substances
  • F01N3/0842—Nitrogen oxides
• • 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
• • 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
  • F02D41/1441—Plural sensors
  • F02D41/1443—Plural sensors with one sensor per cylinder or group of cylinders
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D41/00—Electrical control of supply of combustible mixture or its constituents
  • F02D41/02—Circuit arrangements for generating control signals
  • F02D41/14—Introducing closed-loop corrections
  • F02D41/1438—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor
  • F02D41/1473—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the regulation method
  • F02D41/1475—Regulating the air fuel ratio at a value other than stoichiometry
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D2200/00—Input parameters for engine control
  • F02D2200/02—Input parameters for engine control the parameters being related to the engine
  • F02D2200/08—Exhaust gas treatment apparatus parameters
  • F02D2200/0802—Temperature of the exhaust gas treatment apparatus
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D41/00—Electrical control of supply of combustible mixture or its constituents
  • F02D41/02—Circuit arrangements for generating control signals
  • F02D41/021—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
  • F02D41/0275—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 NOx trap or adsorbent
• • 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
  • F02D41/1446—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 exhaust temperatures
• • 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 a method for controlling the temperature of at least one catalytic converter arranged in an exhaust gas purification system of a lean-running multi-cylinder engine, in which energy can be introduced into the exhaust gas purification system by means of a lambda split, and a corresponding multi-cylinder engine with a lambda split-capable exhaust gas purification system.
• the exhaust gas is passed over at least one catalytic converter, which converts one or more pollutant components of the exhaust gas.
• Catalytic converter which converts one or more pollutant components of the exhaust gas.
• Oxidation catalysts promote the oxidation of unburned hydrocarbons (HC) and carbon monoxide (CO), while reduction catalysts support a reduction of nitrogen oxides (NO x ) in the exhaust gas.
• 3-way catalysts are used to catalyze the conversion of the three aforementioned components (HC, CO, NO x ) at the same time.
• Storage catalysts for example NO x storage catalysts, are also known. These are used in the exhaust gas purification of internal combustion engines which, for reasons of optimizing consumption, are operated at least temporarily in a lean operating mode, that is to say with an oxygen-rich exhaust gas with ⁇ > 1, nitrogen oxides NO x being formed to a high degree.
• the nitrogen oxides NOx can not be fully converted into environmentally neutral nitrogen at a catalytic oxidative conversion of unburned hydrocarbons HC and carbon monoxide CO nitrogen oxides NO x.
• the aforementioned NO x storage catalytic converters are arranged in the exhaust gas channels of internal combustion engines, which store NO x as nitrate in lean operating phases.
• the NO x storage catalytic converter must be regenerated at recurring intervals by switching to rich or substoichiometric operation ( ⁇ ⁇ 1) of the internal combustion engine.
• ⁇ ⁇ 1 rich or substoichiometric operation
• the aforementioned catalysts age due to the exposure to high temperatures, so that the peak conversion rate decreases compared to an undamaged catalyst.
• the maximum permissible temperature in the exhaust system is monitored and limited by setting engine operating parameters, preferably the combustion lambda.
• Heating catalysts is particularly problematic when using primary and main catalysts, since the primary catalysts can be thermally overloaded in an effort to bring the main catalyst to the desired temperature.
• the catalytic converter in particular a main catalytic converter, can be heated in such a way that the catalytic converter is simultaneously subjected to lean and rich exhaust gas.
• the exhaust gas is shifted in one of the two charging paths by a predetermined amount in the "rich" direction and in the other path in a corresponding manner in the opposite direction.
• the advantage of this measure is that the mixed exhaust gas upstream of the catalyst also contains high oxygen and pollutant concentrations. This results in a high conversion of chemically bound energy on the catalyst.
• a catalyst can only. are heated by means of lambda split if it is at least partially active, that is to say heated, since its activity is a prerequisite for the chemical energy input.
• a method for controlling the temperature of a catalytic converter arranged in an exhaust gas cleaning system of a lean-running multi-cylinder engine in which energy can be introduced into the exhaust gas cleaning system by means of a lambda split, the amount or a limitation of the energy input depending on at least one of the parameters catalyst temperature, exhaust gas temperature and Exhaust gas mass flow and / or depending on at least one of the parameters change in the catalyst temperature, the exhaust gas temperature and the exhaust gas mass flow (1st derivative) and / or in dependence on at least one of the parameters change speed of the catalyst temperature, the exhaust gas temperature and the exhaust gas mass flow (2nd derivative) ,
• the lambda-split-capable exhaust gas purification system is preferably designed in such a way that there are at least two passages or exhaust gas paths between the multi-cylinder engine and the at least one catalytic converter, each of which can be supplied with a predeterminable lambda, it being particularly preferred that the exhaust gas purification system has at least one main catalytic converter, its temperature is to be controlled according to the method and has at least two upstream pre-catalysts, each pre-catalyst being arranged in its own exhaust gas path.
• the chemical energy input is preferably controlled by limiting the split factor.
• This is understood here as a measure of the enrichment in one of the exhaust gas paths.
• a request for energy input into the exhaust gas cleaning system is defined as a function of the current catalytic converter temperature or the difference between the current catalytic converter temperature and a predefinable target temperature. Normally, a quick heating up of the catalytic converter to the target temperature is desired, so that high energy inputs into the exhaust system and thus a high basic split factor are required.
• a mixed lambda setpoint of 1.0 is required.
• the risk of a catalyst overload increases with a high chemical proportion in the heating process, so that the limitation of the energy input according to the invention for controlling the temperature of the catalyst is particularly advantageous.
• the chemical energy input or the split factor is limited as a function of the aforementioned parameters with:
• the chemical energy portion of the exhaust gas that can be converted on the catalytic converter is determined by the available reducing agent and oxygen mass flow. Therefore at Regulation to a lambda setpoint upstream of the catalytic converter preferably regulates the lambda in the lean path to the lean lambda value resulting from the required split factor as a function of the measured lambda in front of or behind the main catalytic converter, while the rich path is precontrolled. This prevents problems in the control by a probe usually arranged behind the catalytic converter due to measurement errors on the lambda probe behind the precatalyst of the rich path, for example due to hydrogen cross-sensitivity.
• the stability of the combustion process can reach its limits, so that increased misfires occur. Therefore, in one embodiment of the method according to the invention, when extremely lean lambda values are present on the lean path, either an at least temporary enrichment of the total mixture is permitted, provided the precontrol of the rich path is not adapted accordingly, or influences the precontrol of the rich path in the "lean" direction accepting a withdrawal of the split factor and thus the energy input. This is preferably done when the lambda value in the lean path assumes values of> 1, 3, most preferably> 1, 45.
• the process according to the invention is preferably used for NO x storage catalysts with, if appropriate, upstream pre-catalysts for desulfurization.
• the method according to the invention advantageously achieves a lower load on the catalyst system than according to known methods of the prior art with less restrictively designed lambda split.
• the lean-running multi-cylinder engine according to the invention with a lambda-split-capable exhaust gas cleaning system in which at least one catalytic converter is arranged has, according to the invention, means with which, depending on at least one of the parameters catalyst temperature, exhaust gas temperature and exhaust gas mass flow and / or in dependence on at least one of the parameters change of the catalyst temperature, the exhaust gas temperature and the exhaust gas mass flow (1st derivative) and / or as a function of at least one of the parameters change rate of the catalyst temperature, the exhaust gas temperature and the exhaust gas mass flow (2nd derivative) measures relevant to exhaust gas for controlling the temperature of the at least one catalyst by influencing at least one operating parameter , preferably the lambda value of the multi-cylinder engine can be taken.
• the lambda-split exhaust gas purification system of the multi-cylinder engine is preferably designed such that there are at least two passages or exhaust gas paths between the multi-cylinder engine and the at least one catalytic converter, each of which can be supplied with a predeterminable lambda.
• the exhaust gas purification system has at least one main catalytic converter with at least two upstream pre-catalytic converters, each of which is arranged in its own exhaust gas path, each exhaust gas path being able to be acted upon separately with a predeterminable lambda.
• These means also include a control unit, in which an engine control unit is preferably integrated, in which models and algorithms for the coordinated control of exhaust-gas and power-related measures are stored in digitized form.
• control and coordination of the aforementioned means and other customary means takes place via the control unit or the engine control unit.
• the multi-cylinder engine according to the invention is a gasoline engine, in particular a direct injection gasoline engine, or a diesel engine.
• the exhaust gas cleaning system or the at least one catalytic converter of the exhaust gas cleaning system of the multi-cylinder engine according to the invention advantageously has a reduced noble metal content.
• a significant reduction in the noble metal content compared to the prior art is possible.
• vehicles with direct-injection stratified gasoline engines which in the New European Driving Cycle NEDC have a thermally undamaged catalyst system, consisting of pre-catalyst (s) close to the engine and downstream NO x storage catalyst (s) with a stored sulfur mass ⁇ 0, Achieve 2 g / l catalyst volume and a shift operating time share of at least 250 s, preferably at least 350 s, an HC emission of ⁇ 0.07 g / km and an NO x emission of ⁇ 0.05 g / km, catalysts with noble metal contents of ⁇ 4.67 g / dm 3 (130g / ft 3 ).
• the precious metal content of at least the pre-catalyst (s) can be ⁇ 3.59 g / dm 3 (100 g / ft 3 ) and particularly preferably ⁇ 2.87 g / dm 3 (80 g / ft 3 ) be lowered.
• Figure 1 is a schematic view of an inventive
• Figure 2 is a flow diagram of the method according to the invention.
• FIG. 1 shows a multi-cylinder engine 10, which is followed by a double-flow exhaust gas cleaning system 12.
• Each two cylinders 14, 14 'of the multi-cylinder engine 10 are assigned to the two exhaust gas paths 16, 16' of the exhaust gas cleaning system 12.
• Each exhaust gas path 16, 16 ' has a pre-catalytic converter 18, 18', upstream of which a lambda probe 20, 20 '.
• Downstream of the pre-catalytic converters 18, 18 ', both exhaust gas paths 16, 16' are combined to form a single exhaust gas path 22 in which a main catalytic converter 24 is arranged.
• Downstream of the main catalytic converter 24 there is again a lambda measuring device 26, which can be formed by a lambda probe or an NO x sensor.
• a temperature sensor 28 for determining the exhaust gas temperature or the catalyst temperature is arranged upstream of the main catalytic converter 24.
• An exhaust gas path 16 is charged with rich and the second exhaust line 16 ′ is supplied with lean exhaust gas, the lambda values of the two exhaust lines preferably being split such that after the two exhaust lines 16, 16 ′ have been combined into a single exhaust line 22, a lambda value of approximately 1 is present, which is then applied to the main catalyst 24.
• the signals emitted by the lambda probes 20, 20 ', the lambda measuring device 26 and the temperature sensor 28 are processed in a control unit or engine control unit, not shown here. The method according to the invention is illustrated on the basis of the flow diagram according to FIG.
• a heat flow requirement S10 which results, for example, from the difference between the catalyst temperature TKAT and the target temperature of the main catalyst 24.
• a basic split factor S12 is specified, which is subject to limiting factors S14, S16, and S18.
• the first limiting factor S14 is defined via a map K10, which is based on the catalyst temperature TKAT and the catalyst temperature gradient TKATG. Accordingly, as the catalyst temperature TKAT increases, the energy input is limited, the difference between the catalyst temperature TKAT and the target temperature not being taken into account.
• the catalyst temperature TKAT is also used for a second characteristic map K12 of the second limiting factor S16 and also that
• Catalyst temperature gradient change TKATGAE Catalyst temperature gradient change TKATGAE.
• the split factor is limited in the case of high positive temperature gradients in the main catalytic converter 24, in particular if high temperatures TKAT are already present in the main catalytic converter 24.
• the reduction of the split factor is all the more pronounced if, in addition, the positive temperature gradient TKATG has a progressive increase in order to reliably avoid the risk of the main catalytic converter 24 "running through”.
• the third limiting factor S18 uses a third characteristic map K16 to limit the split factor as a function of the exhaust gas mass flow AMS and the exhaust gas mass flow gradient AMSG, since the cooling effect also decreases with a reduced exhaust gas mass flow and because in operating situations that require a high negative exhaust gas mass flow gradient, the HC and O 2 content in the exhaust gas and thus the chemical energy input increases sharply for a short time.
• the lambda target for the exhaust gas path 16 with the rich exhaust gas in one Step S24 is pre-controlled and the lambda target for the exhaust gas path 16 ′ with the lean exhaust gas is regulated in a step S26 via the lambda value measured after the main catalytic converter 24.

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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)
• Exhaust Gas After Treatment (AREA)
• Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)
• Combined Controls Of Internal Combustion Engines (AREA)

Priority Applications (4)

Applications Claiming Priority (2)

Publications (1)

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Family Applications (1)

Country Status (6)

Cited By (4)

Families Citing this family (15)

Citations (5)

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• 2002
  • 2002-12-30 DE DE10261911A patent/DE10261911A1/de not_active Withdrawn
• 2003
  • 2003-12-12 US US10/541,004 patent/US7356988B2/en not_active Expired - Fee Related
  • 2003-12-12 DE DE50303755T patent/DE50303755D1/de not_active Expired - Lifetime
  • 2003-12-12 CN CNB2003801075630A patent/CN100422530C/zh not_active Expired - Fee Related
  • 2003-12-12 EP EP03789253A patent/EP1581733B1/de not_active Expired - Lifetime
  • 2003-12-12 JP JP2004562741A patent/JP4332120B2/ja not_active Expired - Fee Related
  • 2003-12-12 WO PCT/EP2003/014156 patent/WO2004059150A1/de not_active Ceased

Patent Citations (5)

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