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
  • F01N3/0807—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
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
  • F01N11/00—Monitoring or diagnostic devices for exhaust-gas treatment apparatus, e.g. for catalytic activity
  • F01N11/002—Monitoring or diagnostic devices for exhaust-gas treatment apparatus, e.g. for catalytic activity the diagnostic devices measuring or estimating temperature or pressure in, or downstream of the exhaust apparatus
• • 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
  • F01N2550/00—Monitoring or diagnosing the deterioration of exhaust systems
  • F01N2550/03—Monitoring or diagnosing the deterioration of exhaust systems of sorbing activity of adsorbents or absorbents
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
  • F02B75/00—Other engines
  • F02B75/12—Other methods of operation
  • F02B2075/125—Direct injection in the combustion chamber for spark ignition engines, i.e. not in pre-combustion chamber
• • 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
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D41/00—Electrical control of supply of combustible mixture or its constituents
  • F02D41/30—Controlling fuel injection
  • F02D41/3011—Controlling fuel injection according to or using specific or several modes of combustion
  • F02D41/3017—Controlling fuel injection according to or using specific or several modes of combustion characterised by the mode(s) being used
  • F02D41/3023—Controlling fuel injection according to or using specific or several modes of combustion characterised by the mode(s) being used a mode being the stratified charge spark-ignited mode
  • F02D41/3029—Controlling fuel injection according to or using specific or several modes of combustion characterised by the mode(s) being used a mode being the stratified charge spark-ignited mode further comprising a homogeneous charge spark-ignited mode
• • 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 operating a storage catalytic converter of an internal combustion engine, in particular a motor vehicle, in which the storage catalytic converter is loaded and unloaded with nitrogen oxides.
• the invention also relates to a control device for an internal combustion engine, in particular of a motor vehicle, and an internal combustion engine, in particular for a motor vehicle.
• Such a method, such a control device and such an internal combustion engine are known, for example, in a so-called gasoline direct injection.
• the fuel is injected into the combustion chamber of the internal combustion engine in homogeneous operation during the intake phase or in stratified operation during the compression phase.
• Homogeneous operation is preferably provided for full-load operation of the internal combustion engine, while stratified operation is suitable for idling and part-load operation.
• a direct-injection internal combustion engine switches between the above-mentioned operating modes.
• a storage catalytic converter with which nitrogen oxides can be temporarily stored in order to reduce them during subsequent homogeneous operation.
• This storage catalytic converter is loaded with the nitrogen oxides in shift operation and discharged again in homogeneous operation. This loading and unloading, thermal stresses and poisoning lead to an aging of the storage catalytic converter.
• the object of the invention is to provide a method for operating a storage catalytic converter of an internal combustion engine, with which the aging of the storage catalytic converter can be detected.
• this object is achieved in that the temperature of the exhaust gas flowing through the storage catalytic converter and / or the temperature of the storage catalytic converter is measured and compared with a threshold value.
• the task is solved accordingly.
• Discharging the storage catalytic converter is an exothermic reaction, which therefore releases heat. This leads to an increase in the temperature of the exhaust gases or the storage catalytic converter even during the emission of nitrogen oxides.
• the aging of the storage catalytic converter leads to a lower storage capacity of nitrogen oxides therein. This is equivalent to a lower temperature increase when the storage catalytic converter is discharged, since fewer nitrogen oxides are to be discharged. This reduction in
• Temperature rise is therefore a measure of the aging of the Storage catalytic converter.
• control unit can thus determine the age-related state of the exhaust gas or the storage catalytic converter according to the invention.
• control unit can conclude that aging is no longer acceptable, in which e.g. Adequate exhaust gas cleaning is no longer guaranteed.
• the invention therefore enables simple and inexpensive detection of the aging of the storage catalytic converter.
• the method according to the invention is stable and independent of others
• the invention is largely independent of changes in the sensors involved.
• a temperature increase is measured and compared with a modeled temperature increase, and the difference is compared with an upper limit value.
• an increase in temperature is measured and compared with an increase in temperature which has been measured in a limit catalytic converter, and it becomes the
• the temperature is measured in and / or immediately after the storage catalytic converter.
• the accuracy of the entire process can be increased by combining the two temperature measurements.
• the method according to the invention is used to diagnose the storage capacity of the storage catalytic converter.
• control element which is provided for a control device of an internal combustion engine, in particular a motor vehicle.
• a program is stored on the control element, which is executable on a computing device, in particular on a microprocessor, and is suitable for executing the method according to the invention.
• the invention is thus implemented by a program stored on the control element, so that this control element provided with the program represents the invention in the same way as the method, for the execution of which the program is suitable.
• an electrical storage medium can be used as the control element, for example a read-only memory or a flash memory.
• the figure shows an internal combustion engine 1 of a motor vehicle, in which a piston 2 can be moved back and forth in a cylinder 3.
• the cylinder 3 is provided with a combustion chamber 4 which is delimited inter alia by the piston 2, an inlet valve 5 and an outlet valve 6.
• An intake pipe 7 is coupled to the inlet valve 5 and an exhaust pipe 8 is coupled to the exhaust valve 6.
• Combustion chamber 4 Fuel can be injected into combustion chamber 4 via injection valve 9. The fuel in the combustion chamber 4 can be ignited with the spark plug 10.
• a rotatable throttle valve 11 is accommodated, via which air can be fed to the intake pipe 7.
• the amount of air supplied is dependent on the angular position of the throttle valve 11.
• a catalytic converter 12 is accommodated in the exhaust pipe 8 and serves to clean the exhaust gases resulting from the combustion of the fuel.
• the catalytic converter 12 is a storage catalytic converter 12 ′ which is combined with a three-way catalytic converter 12 ′′.
• the catalytic converter 12 is thus intended, inter alia, to remove nitrogen oxides (NOx) caching.
• a temperature sensor 13 is provided in the catalytic converter 12.
• a temperature sensor 14 is provided in the exhaust pipe immediately after the catalytic converter 12.
• a control device 18 is acted upon by input signals 19, which represent operating variables of the internal combustion engine 1 measured by sensors.
• the control unit 18 generates output signals 20 with which the behavior of the internal combustion engine 1 can be influenced via actuators or actuators.
• the control unit 18 is provided to control and / or regulate the operating variables of the internal combustion engine 1.
• the control unit 18 is provided with a microprocessor, which has stored a program in a storage medium, in particular in a flash memory, which is suitable for carrying out the control and / or regulation mentioned.
• Throttle valve 11 partially opened or closed depending on the desired torque.
• the fuel is injected into the combustion chamber 4 by the injection valve 9 during an induction phase caused by the piston 2.
• Throttle valve 11 sucked air, the injected fuel is swirled and thus distributed substantially evenly in the combustion chamber 4.
• the fuel / air mixture is then compressed during the compression phase in order to then be ignited by the spark plug 10.
• the piston 2 is driven by the expansion of the ignited fuel.
• the resulting torque depends, among other things, on the position of the throttle valve 11 in homogeneous operation.
• the fuel / air mixture is set to La bda equal to one if possible.
• throttle valve 11 is opened wide.
• the fuel is injected from the injection valve 9 into the combustion chamber 4 during a compression phase caused by the piston 2, specifically locally in the immediate vicinity of the spark plug 10 and at a suitable time before the ignition point. Then the fuel is ignited with the aid of the spark plug 10, so that the piston 2 is driven in the now following working phase by the expansion of the ignited fuel.
• the resulting torque largely depends on the injected fuel mass in shift operation.
• the stratified operation is essentially provided for the idle operation and the partial load operation of the internal combustion engine 1.
• the storage catalytic converter 12 ′ of the catalytic converter 12 is loaded with nitrogen oxides during the shift operation. In a subsequent homogeneous operation, the storage catalytic converter 12 'is discharged again and the nitrogen oxides are reduced by the three-way catalytic converter 12' '.
• the storage catalytic converter 12 'absorbs sulfur over time during its continuous loading and unloading with nitrogen oxides. This leads to a limitation of
• Storage capacity of the storage catalytic converter 12 ′ which is referred to below as aging.
• the discharge of the storage catalytic converter 12 ′ represents an exothermic reaction in which heat is generated. This results in an increase in the temperature of the exhaust gases flowing through the storage catalytic converter 12 '. This temperature increase is measured by the temperature sensor 13 and / or by the temperature sensor 14. At the same time, the exothermic reaction also increases the temperature of the storage catalytic converter 12 'itself alternatively or additionally, the temperature sensor 13 and possibly also the temperature sensor 14 measure.
• Internal combustion engine 1 monitors. This can be done by comparing the current temperature increase with a temperature increase that occurs with a new one
• Storage catalyst 12 'or a new catalyst 12 has been measured. Alternatively or additionally, this can be done by comparing the current temperature increase with a modeled temperature increase. Alternatively or additionally, a comparison can also be made with an increase in temperature of a so-called limit catalyst.
• the limit catalytic converter is a catalytic converter that is just still operational or has just become defective.
• control unit 18 concludes that the storage catalytic converter 12 'of the catalytic converter 12 has now reached an age which is no longer acceptable in view of adequate exhaust gas purification.
• the control unit 18 then generates, for example, a signal that can be recognized by the driver or by a workshop and that indicates the required replacement of the storage catalytic converter 12 ′ or the entire catalytic converter 12.
• the difference to the current temperature increase also becomes larger and larger, so that the difference is compared with an associated upper threshold value, upon reaching which the storage catalytic converter 12 'must be replaced.
• the difference to the current temperature increase becomes smaller and smaller, so that the difference is compared with an associated lower threshold value, upon reaching which the storage catalytic converter 12 'must be replaced.
• the comparison can be based on the absolute temperatures.
• the temperature increase due to the exothermic reaction during the discharge of the storage catalytic converter 12 ′ is synonymous with a maximum temperature that is measured by the temperature sensor 13 and / or the temperature sensor 14. This maximum temperature becomes lower over time due to the aging of the storage catalytic converter 12 '. If the maximum temperature falls below a lower threshold value, the storage catalytic converter 12 'must be replaced.
• the above procedure may continue throughout the Operation of the internal combustion engine 1 are used. Alternatively or additionally, it is possible to use the method specifically for diagnosing the storage capacity of the storage catalytic converter 12 '.

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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)

Applications Claiming Priority (3)

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• 1999
  • 1999-12-31 DE DE19963925A patent/DE19963925A1/de not_active Ceased
• 2000
  • 2000-12-20 WO PCT/DE2000/004549 patent/WO2001049994A1/de not_active Application Discontinuation
  • 2000-12-20 JP JP2001549906A patent/JP2003519324A/ja active Pending
  • 2000-12-20 EP EP00991535A patent/EP1159518A1/de not_active Ceased

Non-Patent Citations (1)

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