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
  • F01N9/00—Electrical control of exhaust gas treating apparatus
  • F01N9/005—Electrical control of exhaust gas treating apparatus using models instead of sensors to determine operating characteristics of exhaust systems, e.g. calculating catalyst temperature instead of measuring it directly
• • 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
  • 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
  • F01N11/005—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 the temperature or pressure being estimated, e.g. by means of a theoretical model
• • 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
  • F01N11/007—Monitoring or diagnostic devices for exhaust-gas treatment apparatus, e.g. for catalytic activity the diagnostic devices measuring oxygen or air concentration 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
  • F01N3/02—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
  • F01N3/02—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
  • 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
• • 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 present invention relates to a method for managing the operation of a combustion engine exhaust system of the type comprising a particulate filter coated with a catalytic phase and piloted means for assisting the regeneration of the filter.
• soot particles burn at temperatures of the order of 550 to 600 ° C.
• thermal levels are only rarely reached by the exhaust gases of an automobile diesel engine since, for example in town, the temperature of the exhaust gases varies between 150 and 250 °.
• Electric resistance heating systems in particular heating grates, make it possible to bring the exhaust temperature to a value sufficient to cause combustion of the particles in the filter.
• Other systems propose to increase the temperature of the exhaust gases by injecting an additional quantity of fuel into at least one of the combustion chambers in the form of a post-injection.
• an additional quantity of fuel is injected in a second step.
• a part of this additional quantity of fuel ignites producing an increase in the temperature of the exhaust gases, the rest of this quantity is transformed into partial oxidation products such as carbon monoxide CO and HC hydrocarbons.
• This monoxide and these hydrocarbons can also participate in the increase in exhaust gases by reacting with exothermic reactions before their arrival in the particulate filter. Exothermic reactions are obtained during the passage of an oxidation catalyst disposed upstream of the particle filter.
• an additive such as an organometallic compound to the fuel.
• the particulate filter can be coated with a catalytic phase which aims to provide additional energy during the reactions of hydrocarbons and carbon monoxide.
• the document, FR2774421 discloses such a system for managing the operation of a particulate filter associated with a diesel engine, in particular of a motor vehicle, and describes how the activation of the means for assisting regeneration is triggered as soon as the mass of soot in the filter is greater than a threshold value, this mass of soot being determined from the measurement of the pressure drop across the particulate filter and the operating conditions of the engine.
• the strategy for activating the means of regeneration support is relatively simple. It essentially consists in keeping these means activated for a calibrated period of time or even in maintaining the means activated as long as the load is not passed below a second given threshold value.
• the actuation of the regeneration means leads to a relatively significant overconsumption of fuel, it is therefore advisable to adjust this actuation to the strict minimum.
• Applicant we use as a parameter for detecting the start of a regeneration, the release of energy. This released energy is deducted from the temperature downstream of the filter measured and estimated. This measurement is carried out only when means for assisting regeneration are used. However, for a particulate filter coated with a catalytic phase, regeneration does not result in a characteristic heat release. Indeed, the reduction reactions of the catalytic phase are also exothermic.
• the present invention aims to control the progress of regenerations of a particulate filter coated with a catalytic phase to reduce fuel consumption.
• a method of managing a combustion engine exhaust system of the type comprising a particulate filter coated with a catalytic phase, by which the activation of regeneration assistance means is triggered. according to determined criteria, the operating parameters being adjusted according to the sequence regeneration of the filter, the method being characterized in that it comprises a step of determining the loading state of the particulate filter, carried out either by an estimation of the amount of soot trapped in the filter from a model, either by measuring the amount of soot trapped in the filter from the measurement of the differential pressure, the choice between estimating or measuring the amount of soot trapped depending on the driving conditions of the vehicle, a step continuous monitoring of the regeneration phases of the particulate filter.
• FIG. 1 represents a schematic view of an internal combustion engine equipped with a particle filter coated with a catalytic phase, implementing the method according to the invention.
• an internal combustion engine referenced 1
• This engine is in the example illustrated a diesel engine supercharged by turbocharger with four cylinders in line and direct fuel injection.
• the exhaust line 5 of this engine is equipped with an exhaust system provided with a device for filtering the soot particles emitted.
• the method applies to a particle filter coated with a catalytic phase, called a catalytic filter.
• the engine 1 is supplied with air through an intake circuit 2.
• Appropriate sensors and in particular a flow meter 8, equip this intake circuit to supply information to the engine control computer 3 on the pressure, the temperature or the flow rate of the intake air supplying the engine.
• Fuel injection in the cylinders is ensured by electromagnetic injectors (not shown) opening into the combustion chambers and controlled by the engine control computer 3 from a pressurized fuel circuit 4 of the common rail type also called high pressure supply system with common rail.
• the exhaust gases discharged in line 5 pass through a catalytic filter 6.
• a portion of the exhaust gases can be recycled on intake by means of an EGR circuit 11 of conventional design comprising a valve 12, the opening of which is controlled by the computer 3.
• This engine control computer 3 is made up so classic of a microprocessor or central processing unit CPU, random access memories RAM, read-only memories ROM, analog-digital converters A / D, and various interfaces of inputs and outputs.
• the microprocessor of the injection computer 3 includes electronic circuits and appropriate software for processing the signals from the various sensors, deducing the states of the engine and generating the appropriate control signals intended in particular for the various actuators controlled.
• the computer 3 therefore controls the fuel pressure in the rail and the opening of the injectors, on the basis of the information delivered by the various sensors and in particular of the admitted air mass, of the engine speed as well as of formulas and Memorized calibrations to achieve the desired consumption and performance levels.
• the computer 3 is also suitable for managing the operation of the exhaust system and in particular of the catalytic filter 6.
• the computer 3 deduces from the information provided in particular by the pressure sensors 7, the filling level of the filter.
• the computer 3 then triggers, as a function of the value of the soot loading of the filter, a regeneration phase in accordance with suitable strategies.
• This regeneration phase essentially consists in increasing the temperature of the exhaust gases passing through the filter 6 so as to ignite the trapped particles. This increase in temperature is initiated by the activation of appropriate means of aid for regeneration, hereinafter generically called heating means.
• Different heating means can be used, one can for example mention electric heating resistors arranged in the flow of the exhaust gases, or even a rise in the temperature of the exhaust gases by afterburning.
• the computer 3 is also suitable for implementing a control of the triggering and the progress of the regeneration of the filter and a control of the operation and the integrity of the filter including in particular a driver alert in the event of a malfunction.
• the method for managing the operation of the particle filter according to. the invention therefore consists in optimizing the duration of activation of the heating means to minimize their impact on the fuel consumption of the vehicle.
• the principle of the method according to the invention is to precisely determine the loading state of the particle filter and to follow the progress of the regeneration phases in order to limit in particular the duration of implementation of the aid means. to regeneration.
• the loading level is determined, by a first strategy, from a measurement of a physical quantity characteristic of the loading level.
• This quantity is according to the invention, the differential pressure used in a formula making it possible to deduce the mass of soot accumulated in the particle filter.
• the patent application registered under the number FR98- 09232 describes an example of a method for determining the mass of soot contained in the particulate filter from the value of the differential pressure.
• the loading level is determined, by a second strategy, from an estimate of the loading state of the particle filter.
• This estimate can be based either on a particle emission model or as a function of the number of kilometers traveled.
• An example of a particle emission model is described in the patent application registered under the number FR99-12548.
• the estimation of the loading level of the filter as a function of the mileage traveled is made by experience.
• the first driving condition or conditions substantially represent city traffic or short-term extra-urban journeys of the order of a few minutes.
• the second driving condition or conditions exclusively represent prolonged extra-urban traffic, for example beyond several minutes.
• the latter defines the type of running of the vehicle. Indeed, a constant speed representative of a high speed, for a duration of several consecutive minutes indicates an extra-urban circulation.
• the computer updates the loading level of the particle filter. This update begins with the definition of the type of driving.
• the computer 3 triggers or continues the strategy for determining the loading state of the corresponding particle filter.
• the new loading level of the particle filter is then memorized until the next update.
• One of the peculiarities of a particulate filter coated with a catalytic phase is that under special driving conditions, thermal conditions are met so that spontaneous regenerations take place, without putting into action the means for assisting in the regeneration.
• the rolling meeting the thermal conditions causing spontaneous regeneration consists of a long motorway rolling or a long rolling at a steady pace.
• Spontaneous regenerations can be taken into account in the step of determining the loading state.
• the second strategy is based on the estimation of the amount of soot produced by the engine. This strategy consists in fact of periodically increasing the value of the level of loading, according to the distance traveled or according to the model of emission of particles.
• the computer 3 When the computer 3 detects, from the monitoring of the operating parameters of the engine, that the running of the vehicle corresponds to running meeting the thermal conditions causing spontaneous regeneration, the computer 3 initiates the initialization of the value of the level of loading at zero.
• the method according to the invention also includes a step of continuously monitoring the progress of the regenerations of the particle filter. This step occurs when a regeneration phase is triggered by the computer by activating the regeneration assistance means, after exceeding a determined loading threshold of the particle filter.
• the monitoring step is active during the entire regeneration phase.
• This step includes a step of detecting the start of regeneration.
• the combustion temperature of the soot is of the order of 550 ° C. Consequently, a detection of a temperature downstream of the filter greater than 550 ° C. indicates a combustion of the particles of the filter and therefore the start of a regeneration.
• the step of detecting a regeneration may consist in monitoring the evolution of the mass of soot over time after activation of the means for assisting regeneration.
• the step of detection consists in determining the ratio between the mass of soot at the time of initiation of regeneration and the mass of soot observed at regular intervals after actuation of the means for assisting regeneration. Then, this ratio is compared with a determined threshold value representative of a large decrease in the mass of soot. This decrease is then indicative of a regeneration.
• the mass of soot at the time of triggering is known as soon as the regeneration aid means are put into action since this value is compared to a triggering threshold. Otherwise, the mass of soot at the time of triggering corresponds to the triggering threshold.
• the mass of soot observed after activation of the regeneration assistance means is determined by means of the first strategy for determining the loading level described above.
• the detection of the start of regeneration consists in measuring the value of the richness of the exhaust gases downstream or downstream and upstream of the particle filter.
• a first respectively second richness probe (not shown) is arranged downstream, respectively upstream of the filter.
• Wealth probes are either proportional or not.
• this value is monitored so that a significant increase in the richness detected by the computer 3 receiving the signals from the probe indicates combustion of the particles. Indeed, the combustion of the particles consumes, at least in part, the oxygen of the exhaust gases, thus inducing a characteristic decrease in the richness downstream of the filter.
• the detection, by the computer 3 receiving the signals from the two probes, of a richness downstream greater than the richness measured upstream indicates a start of regeneration.
• the means for assisting regeneration are used throughout the duration of the regeneration in order to ensure complete combustion of the particles.
• the step of monitoring the progress of regenerations of the particle filter comprises a step of detecting the end of regeneration.
• the detection of the end of regeneration is estimated by modeling the combustion of the soot in the filter.
• the computer 3 determines the duration of the combustion of the soot from, on the one hand the level of loading at the time of triggering and operating parameters of the engine at the time of regeneration, and on the other hand a mathematical model and / or specific mapping. This combustion duration then corresponds to the duration of activation of the regeneration assistance means triggered by the computer.
• the mathematical model and / or the specific cartography are established by experience and / or test.
• the detection of the end of regeneration can also consist in measuring continuously or at regular intervals, after the activation of the regeneration assistance means, the value of the differential pressure of the particulate filter. This value received by the computer is then compared to a determined threshold value corresponding to the differential pressure of the empty particle filter. When the computer 3 detects equality between these two values, indicating the end of the regeneration, it stops the activation of the regeneration assistance means.
• the invention is not limited to the embodiment which has just been described as an example.

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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)
• Analytical Chemistry (AREA)
• Processes For Solid Components From Exhaust (AREA)
• Exhaust Gas After Treatment (AREA)

Applications Claiming Priority (3)

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• 2001
  • 2001-09-14 FR FR0111915A patent/FR2829798B1/fr not_active Expired - Lifetime
• 2002
  • 2002-09-13 WO PCT/FR2002/003128 patent/WO2003025355A1/fr not_active Application Discontinuation
  • 2002-09-13 EP EP02779634A patent/EP1425498A1/de not_active Withdrawn

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