WO2008050049A1 - Method and device for regulating an amount of fuel to be injected late in order to regenerate an internal combustion engine particulate filter - Google Patents

Method and device for regulating an amount of fuel to be injected late in order to regenerate an internal combustion engine particulate filter Download PDF

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Publication number
WO2008050049A1
WO2008050049A1 PCT/FR2007/052209 FR2007052209W WO2008050049A1 WO 2008050049 A1 WO2008050049 A1 WO 2008050049A1 FR 2007052209 W FR2007052209 W FR 2007052209W WO 2008050049 A1 WO2008050049 A1 WO 2008050049A1
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WO
WIPO (PCT)
Prior art keywords
engine
catalyst
temperature
correction
operating point
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Application number
PCT/FR2007/052209
Other languages
French (fr)
Inventor
Marc Daneau
Mohammed Ouazzani-Chahdi
Eric Dufay
Original Assignee
Renault S.A.S
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Application filed by Renault S.A.S filed Critical Renault S.A.S
Publication of WO2008050049A1 publication Critical patent/WO2008050049A1/en

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/02—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust
    • F01N3/021—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters
    • F01N3/033—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters in combination with other devices
    • F01N3/035—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters in combination with other devices with catalytic reactors, e.g. catalysed diesel particulate filters
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • 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
    • F02D41/021—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
    • F02D41/029—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 particulate filter
    • 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
    • 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
    • F02D41/38—Controlling fuel injection of the high pressure type
    • F02D41/40—Controlling fuel injection of the high pressure type with means for controlling injection timing or duration
    • F02D41/402—Multiple injections
    • F02D41/405—Multiple injections with post injections
    • 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
    • F01N2430/00—Influencing exhaust purification, e.g. starting of catalytic reaction, filter regeneration, or the like, by controlling engine operating characteristics
    • F01N2430/08—Influencing exhaust purification, e.g. starting of catalytic reaction, filter regeneration, or the like, by controlling engine operating characteristics by modifying ignition or injection timing
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/12—Improving ICE efficiencies
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/40—Engine management systems

Definitions

  • the present invention is in the field of the treatment of the exhaust gases of internal combustion engines for a motor vehicle of the diesel type.
  • the invention relates to a device for regulating the amount of fuel to be injected late in the combustion chambers of the internal combustion engine so as to allow a temperature rise in a particulate filter to proceed with the regeneration of this filter by combustion of particles trapped there.
  • the invention also relates to a method for regulating such a quantity of fuel to be injected late in the combustion chambers of the internal combustion engine.
  • exhaust aftertreatment systems arranged in the exhaust line of the engines are generally provided. These post-treatment systems make it possible to reduce emissions of particles and nitrogen oxides as well as carbon monoxide and unburned hydrocarbons.
  • post-processing systems operate discontinuously for specified periods. In normal operation, the systems trap pollutants but only treat them during so-called regeneration phases. To be regenerated, a post-treatment system comprising a particulate filter requires a combustion mode specific to the internal combustion engine to ensure a suitable temperature and / or wealth level.
  • diesel - type combustion engines emit in their exhaust more quantities of polluting soot, which are generally called particles.
  • a filter is provided in the exhaust line of the combustion engine, downstream of the combustion chambers of the engine. This filter retains the soot particles that accumulate in it as as the engine is used.
  • Internal combustion engines also emit reducing pollutants such as HC, CO, etc. In the presence of oxygen and catalytic materials such as for example platinum, and at high temperature, these reducing pollutants can be oxidized.
  • an oxidation catalyst device is generally present in the exhaust line upstream of the particulate filter.
  • Such late injection of fuel also has the effect of increasing the internal temperature of the catalyst device.
  • This has a disadvantage if the temperature becomes too high, the catalytic particles, for example platinum, then risking to to agglutinate and reduce the contact area with the exhaust gas, and thereby the performance of the catalyst. If the temperature is very high, the ceramic materials that are generally used to support the catalytic materials may even collapse thereby creating holes in the catalyst.
  • the regeneration operation of the particle filter is carried out periodically as soon as a quantity of particles in the filter is detected which is too large. This detection can be obtained for example by a measurement of differential pressure upstream and downstream of the particle filter or by any other appropriate means.
  • the regeneration operation is carried out when the vehicle engine is running and must not be discernible by the driver and passengers of the vehicle.
  • the amount of fuel injected late into the combustion chambers is generally regulated as a function of the outlet temperature of the catalyst, which is at the same time the temperature of the catalyst. input of the particulate filter.
  • the French patent application 2 81 1370 (DAIMLER BENZ) is similar to the aforementioned French patent application 2 846 049.
  • DIMLER BENZ The French patent application 2 81 1370
  • difficulties can be observed during the transient phases, that is to say when significant variations in the operation of the motor are required by the driver, for example during acceleration phases.
  • the catalyst device has a significant thermal inertia, so that the measurement of the temperature at the outlet of the catalyst retranscribes the temperature variations inside the catalyst device with a few tens of seconds of delay.
  • French Patent Application 2,864,992 provides for measuring not only the temperature at the outlet of the catalyst, but also the temperature upstream of the catalyst to improve the regulation and to take into account the inertia of the catalyst.
  • PSA patent application 2,862,100 proposes to determine the state of the primed or non-primed catalyst device by measuring the temperature upstream and downstream of the catalyst. It then becomes possible to limit the fuel injection post-flow rates in a foot-lift state of the accelerator or in engine idling phases.
  • the object of the present invention is to improve the control performance of the quantity of fuel injected late into the combustion chambers so as to take best account of the transient operating phases.
  • the present invention also aims to improve the speed of regulation during stable operation of the combustion engine.
  • a device allows the regulation of a fuel quantity to be injected late into the combustion chambers of a diesel engine internal combustion engine, comprising a particulate filter mounted in a the exhaust line of the engine and a catalytic oxidation means integrated or not into the particulate filter.
  • the late injection is triggered by appropriate means for periods of time for the regeneration of the particle filter by combustion of the particles trapped in the filter.
  • the device comprises temperature sensors upstream and downstream of the catalytic oxidation means and a regulator receiving the difference between the value of the temperature measured downstream of the catalyst and a set value.
  • the regulator is able to provide a fuel quantity value to be injected late.
  • the device further comprises a correction module capable of estimating a correction to be applied to the fuel quantity value to be injected late.
  • This module comprises a memorized map of the temperature upstream of the catalyst in steady state, as a function of the operating point of the engine and the memorized maps of quantities representative of the dynamic evolution of the catalytic oxidation process, as a function of the operating point. of the motor. Means are also provided for adding said correction to the fuel quantity value to be injected late, provided by the regulator.
  • the correction module comprises a stored map of a first gain of temperature values downstream and upstream of the catalyst, as a function of the operating point of the engine, and a stored map of a first time of catalyst response, depending on the operating point of the engine.
  • the correction module may also include a stored map of a second gain of fuel quantity values injected late and temperature downstream of the catalyst, depending on the operating point of the engine, and a memorized map of a second time. catalyst response, depending on the operating point of the engine.
  • the correction module preferably comprises means for filtering the gains mapped by the mapping response times, as a function of the operating point of the engine.
  • Another aspect of the invention relates to a method of regulating a fuel quantity to be injected late into the combustion chambers of a diesel engine internal combustion engine, comprising a particle filter mounted in the fuel line. engine exhaust and catalytic oxidation means integrated or not in the particulate filter.
  • the late injection is triggered by periods of time for the regeneration of the particulate filter by combustion of particles trapped in the filter.
  • the quantity of fuel injected late is regulated as a function of the difference between the value of the temperature measured downstream of the catalyst and a set value, and the quantity of fuel injected late is applied to the regulated value, an estimated correction as a function of the dynamic evolution of the oxidation process for each stabilized operating point of the catalyst.
  • the correction may, for example, be estimated from a stored map of the temperature values upstream of the catalyst in steady state, as a function of the operating point of the engine.
  • the thermal inertia of the catalyst and the exothermic nature of the catalytic reactions are also preferably taken into account in estimating the correction.
  • Figure 1 shows schematically the exhaust line of an internal combustion engine
  • Figure 2 shows schematically the main elements of a control device according to the invention
  • Figure 3 illustrates the main elements of a correction module used in the regulation according to the invention.
  • the internal combustion engine 1 shown very schematically, is a four-cylinder diesel engine.
  • the engine combustion chambers shown schematically and referenced 2 are supplied with compressed air via an intake duct 3.
  • the fresh air admitted is compressed by a turbo compressor 4 whose compressor is rotated by a turbine traversed by the gases.
  • an exhaust line 6 which comprises a catalyst device 7 followed by a particulate filter (FAP).
  • FAP particulate filter
  • An ECU electronic control unit referenced 9 provides the control of the operation of the engine 1 and also allows the control of the regeneration of the particle filter 8.
  • the electronic control unit 9 which receives various information of operating parameters of the The motor 10 is capable of emitting a control signal via the connection 11 for the injection into the combustion chambers 2 of a certain quantity of fuel at a late moment, that is to say after the top dead center, so as to increase the amount of unburned fuel and the temperature of the exhaust gas for a regeneration phase of the particulate filter.
  • FIG. 1 also shows various sensors and in particular a pressure sensor 12 mounted downstream of the particulate filter 8 and a pressure sensor 13 mounted upstream of the particulate filter 8.
  • the differential pressure ⁇ P between the upstream and the downstream of the particle filter 8 is determined by a module 14 which emits a differential pressure signal through the connection 15 which brings this signal to the electronic control unit 9.
  • FIG. 1 also shows a temperature sensor 16 which determines the temperature at the outlet of the catalyst 7.
  • a second temperature sensor 17 determines the temperature upstream of the catalyst 7, ie, T am. These temperatures are brought by the connections. 18 and 19 to the electronic control unit 9.
  • FIG. 2 The main elements of the regulation are illustrated in FIG. 2, where there are the same elements bearing the same references and in particular the motor 1 and the electronic control unit 9 as well as the sensor 16 determining the temperature T s at the output. of the catalyst device 7.
  • the control essentially comprises a regulator 20, which is here by way of example a regulator of the proportional integral derivative type (PID).
  • the quantity to be regulated is the difference ⁇ which is fed to the input of the regulator 20 and which corresponds to the difference between a set temperature T cons and the temperature T s measured at the outlet of the catalyst device which is fed to the negative input of a comparator 21 which receives on its positive input the value of the set temperature T cons .
  • the regulation device further comprises a correction module 22 denoted COR in FIG. 2 which receives on its input the value of the temperature measured upstream of the catalyst device, that is to say T am. from the sensor 17 and which is capable of transmitting a correction value C or which is added in the adder 23 to the value of the quantity of fuel to be injected which is determined by the regulator 20.
  • a correction module 22 denoted COR in FIG. 2 which receives on its input the value of the temperature measured upstream of the catalyst device, that is to say T am. from the sensor 17 and which is capable of transmitting a correction value C or which is added in the adder 23 to the value of the quantity of fuel to be injected which is determined by the regulator 20.
  • FIG. 3 more precisely illustrates the main elements of the correction module 22.
  • a memorized map 24 as a function of the engine rotation speed denoted N and the engine torque denoted C provides a temperature value upstream of the catalyst device T am have in steady state for different operating points of the engine. This expected value from mapping 24 is brought to the input
  • the comparator 25 also receives on its positive input the upstream temperature T am as measured by the sensor 17. The comparator 25 thus establishes an upstream ⁇ T deviation which takes into account the operating point of the engine in steady state. stabilized.
  • a gain is applied to the first correction thus obtained.
  • the correction module 22 comprises a map 26 as a function of the operating point of the engine represented by the rotation speed N and the engine torque C, this map giving for each operating point of the engine in steady state the value of the engine.
  • This gain is further filtered in the filter 27 noted F1 by means of a response time ti which takes into account the operating dynamics of the catalyst device.
  • This response time t i is determined as a function of the operating point of the engine by a map 28 as a function of the rotation speed of the engine N and the engine torque C.
  • the correction module 22 also comprises a means for establishing a correction on the quantity of fuel to be injected to reach the set temperature.
  • a map 30 makes it possible to determine a second gain K 2 as a function of the operating point of the engine, that is to say the rotation speed of the motor N and the torque C.
  • the value of this gain K 2 corresponds to the amount of fuel injected Q pos t divided by the value of the outlet temperature T s of the catalyst is:
  • K 2 Qpost T 8 .
  • This gain is the subject of a filtering in the filter 31 noted F2 by means of a response time t 2 of the catalyst device 7, determined as a function of the instantaneous operating point of the engine in steady state by means of a mapping
  • the response time t 2 resulting from this mapping is brought to the input of the filter 31 so as to obtain a filtered gain which is fed to a processing module 33 also receiving the signal. correction relating to the outlet temperature of the catalyst device.
  • the processing module 33 determines the correction value Cor which must be applied to the quantity of fuel to be injected.
  • the gains K 1 and K 2 and the response times t 1 and t 2 all come from mappings established under static conditions and all depend on the operating point of the engine under steady state conditions.
  • the addition of this value of correction makes it possible to obtain better regulation of the temperature at the outlet of the catalyst device during the transient modes, corresponding, for example, to large variations of the motor parameters during relatively short time intervals.
  • the setpoint overruns are perfectly controlled during unstable vehicle running conditions.
  • the speed of regulation during stable rolling phases is improved.

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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)
  • Processes For Solid Components From Exhaust (AREA)
  • Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)

Abstract

The device comprises a temperature sensor (17) sensing the temperature Tupstream upstream of a catalytic oxidation means and a regulator (20) receiving the difference between the temperature Ts measured downstream of the catalytic converter and a setpoint value. The device further comprises a correction module (22) capable of estimating a correction to be applied to the amount of fuel that is to be injected late, said module comprising a stored map of the temperature upstream of the catalytic converter in steady state conditions as a function of the engine operating point and the stored maps of parameters representative of the dynamic change in the catalytic oxidation process as a function of the engine operating point, and means (23) for adding said correction to the amount of fuel to be injected late as supplied by the regulator (20).

Description

Dispositif et procédé de régulation d'une quantité de carburant à inj ecter tardivement pour la régénération d'un filtre à particules de moteur à combustion interne Device and method for regulating a fuel quantity to be injected late for the regeneration of an internal combustion engine particle filter
La présente invention se situe dans le domaine du traitement des gaz d' échappement des moteurs à combustion interne pour véhicule automobile du type diesel. L 'invention a pour objet un dispositif de régulation de la quantité de carburant à injecter tardivement dans les chambres de combustion du moteur à combustion interne de façon à permettre une élévation de température dans un filtre à particules pour procéder à la régénération de ce filtre par combustion des particules qui s 'y trouvent piégées. L 'invention a également pour objet un procédé de régulation d'un telle quantité de carburant à injecter tardivement dans les chambres de combustion du moteur à combustion interne. Pour satisfaire à la baisse des seuils admis pour les émissions de gaz polluants des véhicules automobiles, on prévoit généralement des systèmes de post-traitement des gaz d' échappement disposés dans la ligne d' échappement des moteurs. Ces systèmes de post-traitement permettent de réduire notamment les émissions de particules et d'oxydes d' azote ainsi que le monoxyde de carbone et les hydrocarbures imbrûlés. Ces systèmes de post-traitement fonctionnent de manière discontinue pendant des périodes déterminées. En fonctionnement normal, les systèmes piègent les polluants mais ne les traitent que lors des phases dites de régénération. Pour être régénéré, un système de post traitement comportant un filtre à particules nécessite un mode de combustion spécifique du moteur à combustion interne permettant de garantir un niveau de température et/ou de richesse convenables.The present invention is in the field of the treatment of the exhaust gases of internal combustion engines for a motor vehicle of the diesel type. The invention relates to a device for regulating the amount of fuel to be injected late in the combustion chambers of the internal combustion engine so as to allow a temperature rise in a particulate filter to proceed with the regeneration of this filter by combustion of particles trapped there. The invention also relates to a method for regulating such a quantity of fuel to be injected late in the combustion chambers of the internal combustion engine. In order to meet the lower thresholds for emissions of gaseous pollutants from motor vehicles, exhaust aftertreatment systems arranged in the exhaust line of the engines are generally provided. These post-treatment systems make it possible to reduce emissions of particles and nitrogen oxides as well as carbon monoxide and unburned hydrocarbons. These post-processing systems operate discontinuously for specified periods. In normal operation, the systems trap pollutants but only treat them during so-called regeneration phases. To be regenerated, a post-treatment system comprising a particulate filter requires a combustion mode specific to the internal combustion engine to ensure a suitable temperature and / or wealth level.
Les moteurs à combustion du type diesel, en raison de leur fonctionnement spécifique, émettent dans leurs gaz d' échappement des quantités plus importantes de suies polluantes que l' on nomme généralement particules. Afin de limiter les émissions de ces particules dans l' atmosphère, on dispose un filtre dans la ligne d' échappement du moteur à combustion, en aval des chambres de combustion du moteur. Ce filtre retient les particules de suie qui s 'accumulent en son sein au fur et à mesure de l'utilisation du moteur. Les moteurs à combustion interne émettent également des polluants réducteurs tels que HC, CO, etc .. En présence d' oxygène et de matériaux catalytiques tel que par exemple du platine, et à température élevée, ces polluants réducteurs peuvent être oxydés. Pour obtenir cette oxydation, on dispose généralement dans la ligne d' échappement un dispositif catalyseur d'oxydation en amont du filtre à particules. Il est également possible de concevoir un filtre à particules dit catalytique qui comprend en son sein un matériau catalytique réalisant cette oxydation. L 'accumulation des particules de suie dans le filtre finit par obturer celui-ci créant une forte contre pression à l'échappement du moteur, ce qui diminue considérablement ses performances. Afin de retrouver les performances normales du moteur, on procède périodiquement à une opération d' oxydation des particules contenues dans le filtre à particules. Cette procédure généralement appelée « régénération du filtre à particules» est obtenue par une élévation de la température interne du filtre à particules qui entraîne l'initialisation et le maintien de la combustion des particules se trouvant piégées dans le filtre.Because of their specific operation, diesel - type combustion engines emit in their exhaust more quantities of polluting soot, which are generally called particles. In order to limit the emissions of these particles into the atmosphere, a filter is provided in the exhaust line of the combustion engine, downstream of the combustion chambers of the engine. This filter retains the soot particles that accumulate in it as as the engine is used. Internal combustion engines also emit reducing pollutants such as HC, CO, etc. In the presence of oxygen and catalytic materials such as for example platinum, and at high temperature, these reducing pollutants can be oxidized. In order to obtain this oxidation, an oxidation catalyst device is generally present in the exhaust line upstream of the particulate filter. It is also possible to design a so-called catalytic particulate filter which comprises within it a catalytic material producing this oxidation. The accumulation of soot particles in the filter eventually closes it creating a strong counter pressure to the engine exhaust, which significantly reduces its performance. In order to find the normal performance of the engine, it is periodically carried out an oxidation operation of the particles contained in the particulate filter. This procedure generally called "particle filter regeneration" is achieved by raising the internal temperature of the particulate filter which initiates and maintains the combustion of particles trapped in the filter.
Pour obtenir une telle élévation de température, on procède généralement à une injection retardée de carburant dans les chambres de combustion du moteur. On injecte ainsi du carburant après le point mort haut lors de la phase de détente ce qui a pour effet d' augmenter la température des gaz d' échappement. On peut également procéder à une ou plusieurs injections tardives consistant à injecter du carburant après une période de temps plus importante après le point mort haut. Ce carburant ne brûle pas dans la chambre de combustion, mais au contraire dans la partie catalytique de la ligne d' échappement. L 'oxydation des produits réducteurs contenus dans les gaz d' échappement tels que HC et CO, qui intervient sur les sites catalytiques, augmente la température lors du passage des gaz d' échappement sur ces sites catalytiques.To obtain such a rise in temperature, it is generally carried out a delayed injection of fuel into the combustion chambers of the engine. Thus fuel is injected after the top dead center during the expansion phase which has the effect of increasing the temperature of the exhaust gas. One or more late injections can also be made by injecting fuel after a longer period of time after top dead center. This fuel does not burn in the combustion chamber, but on the contrary in the catalytic part of the exhaust line. The oxidation of the reducing products contained in the exhaust gases such as HC and CO, which intervenes on the catalytic sites, increases the temperature during the passage of the exhaust gases on these catalytic sites.
Une telle injection tardive de carburant a également pour effet d' augmenter la température interne du dispositif catalyseur. Cela présente un inconvénient si la température devient trop importante, les particules catalytiques, par exemple du platine, risquant alors de s' agglutiner et de diminuer la surface de contact avec les gaz d' échappement, et de ce fait les performances du catalyseur. Si la température est très élevée, les matériaux céramiques qui sont généralement utilisés pour supporter les matériaux catalytiques peuvent même s 'effondrer créant alors des trous dans le catalyseur.Such late injection of fuel also has the effect of increasing the internal temperature of the catalyst device. This has a disadvantage if the temperature becomes too high, the catalytic particles, for example platinum, then risking to to agglutinate and reduce the contact area with the exhaust gas, and thereby the performance of the catalyst. If the temperature is very high, the ceramic materials that are generally used to support the catalytic materials may even collapse thereby creating holes in the catalyst.
L ' opération de régénération du filtre à particules s ' effectue périodiquement dès que l' on détecte une quantité de particules dans le filtre trop importante. Cette détection peut être obtenue par exemple par une mesure de pression différentielle en amont et en aval du filtre à particules ou par tout autre moyen approprié. L ' opération de régénération s' effectue lorsque le moteur du véhicule fonctionne et ne doit pas être discernable par le conducteur et les passagers du véhicule.The regeneration operation of the particle filter is carried out periodically as soon as a quantity of particles in the filter is detected which is too large. This detection can be obtained for example by a measurement of differential pressure upstream and downstream of the particle filter or by any other appropriate means. The regeneration operation is carried out when the vehicle engine is running and must not be discernible by the driver and passengers of the vehicle.
Pour éviter des élévations de température trop importantes et piloter la phase de régénération, on procède généralement à une régulation de la quantité de carburant injectée tardivement dans les chambres de combustion en fonction de la température de sortie du catalyseur qui est en même temps la température d'entrée du filtre à particules.To avoid excessive temperature rises and to control the regeneration phase, the amount of fuel injected late into the combustion chambers is generally regulated as a function of the outlet temperature of the catalyst, which is at the same time the temperature of the catalyst. input of the particulate filter.
La demande de brevet français 2 846 049 (RENAULT) décrit une telle régulation de la quantité de carburant injectée pendant les phases de régénération à partir de l' écart entre la température des gaz d' échappement mesurée en aval du catalyseur d' oxydation et une valeur de consigne de cette température.The French patent application 2,846,049 (RENAULT) describes such a regulation of the quantity of fuel injected during the regeneration phases from the difference between the temperature of the exhaust gas measured downstream of the oxidation catalyst and a setpoint of this temperature.
La demande de brevet français 2 81 1 370 (DAIMLER BENZ) est similaire à la demande de brevet français 2 846 049 précitée. On constate cependant, avec de telles régulations, des difficultés pendant les phases transitoires c' est-à-dire lorsque des variations importantes de fonctionnement du moteur sont demandées par le conducteur, par exemple lors de phases d' accélération. En effet, le dispositif catalyseur présente une inertie thermique non négligeable, de sorte que la mesure de la température à la sortie du catalyseur retranscrit les variations de la température à l' intérieur du dispositif catalyseur avec quelques dizaines de secondes de retard.The French patent application 2 81 1370 (DAIMLER BENZ) is similar to the aforementioned French patent application 2 846 049. However, with such regulations, difficulties can be observed during the transient phases, that is to say when significant variations in the operation of the motor are required by the driver, for example during acceleration phases. Indeed, the catalyst device has a significant thermal inertia, so that the measurement of the temperature at the outlet of the catalyst retranscribes the temperature variations inside the catalyst device with a few tens of seconds of delay.
La demande de brevet français 2 864 992 (BOSCH) prévoit de mesurer non seulement la température en sortie du catalyseur, mais également la température en amont du catalyseur afin d' améliorer la régulation et de tenir compte de l' inertie du catalyseur.French Patent Application 2,864,992 (BOSCH) provides for measuring not only the temperature at the outlet of the catalyst, but also the temperature upstream of the catalyst to improve the regulation and to take into account the inertia of the catalyst.
Pour résoudre ces difficultés, la demande de brevet 2 862 100 (PSA) propose de déterminer l 'état amorcé ou non du dispositif catalyseur par une mesure de la température en amont et en aval du catalyseur. Il devient alors possible de limiter les débits de post injection de carburant dans un état de levée de pied de l'accélérateur ou dans des phases de ralenti du moteur.To solve these difficulties, the patent application 2,862,100 (PSA) proposes to determine the state of the primed or non-primed catalyst device by measuring the temperature upstream and downstream of the catalyst. It then becomes possible to limit the fuel injection post-flow rates in a foot-lift state of the accelerator or in engine idling phases.
Aucune de ces solutions ne donne cependant entière satisfaction et ne permet une véritable amélioration de la régulation du débit de carburant injecté tardivement lors des phases transitoires de fonctionnement du moteur. On constate en effet des dépassements importants de la consigne de température à la sortie du dispositif catalyseur pouvant entraîner le dépassement des limites thermo mécaniques du catalyseur.None of these solutions, however, gives complete satisfaction and does not allow a real improvement in the regulation of the fuel flow injected late during the transient phases of operation of the engine. In fact, there are significant overshoots of the temperature set point at the outlet of the catalyst device that can lead to exceeding the thermo mechanical limits of the catalyst.
La présente invention a pour obj et d' améliorer les performances de régulation de la quantité de carburant injectée tardivement dans les chambres de combustion de façon à tenir compte au mieux des phases transitoires de fonctionnement. La présente invention a également pour objet d'améliorer la rapidité de la régulation lors d'un fonctionnement stable du moteur à combustion.The object of the present invention is to improve the control performance of the quantity of fuel injected late into the combustion chambers so as to take best account of the transient operating phases. The present invention also aims to improve the speed of regulation during stable operation of the combustion engine.
Dans un mode de réalisation, un dispositif selon l' invention permet la régulation d'une quantité de carburant à injecter tardivement dans les chambres de combustion d'un moteur à combustion interne de véhicule automobile du type Diesel, comprenant un filtre à particules monté dans la ligne d' échappement du moteur et un moyen d'oxydation catalytique intégré ou non dans le filtre à particules. L' injection tardive est déclenchée par des moyens appropriés par périodes de temps pour la régénération du filtre à particules par combustion des particules piégées dans le filtre.In one embodiment, a device according to the invention allows the regulation of a fuel quantity to be injected late into the combustion chambers of a diesel engine internal combustion engine, comprising a particulate filter mounted in a the exhaust line of the engine and a catalytic oxidation means integrated or not into the particulate filter. The late injection is triggered by appropriate means for periods of time for the regeneration of the particle filter by combustion of the particles trapped in the filter.
Le dispositif comprend des capteurs de la température en amont et en aval du moyen d' oxydation catalytique et un régulateur recevant l' écart entre la valeur de la température mesurée en aval du catalyseur et une valeur de consigne. Le régulateur est capable de fournir une valeur de quantité de carburant à injecter tardivement.The device comprises temperature sensors upstream and downstream of the catalytic oxidation means and a regulator receiving the difference between the value of the temperature measured downstream of the catalyst and a set value. The regulator is able to provide a fuel quantity value to be injected late.
Le dispositif comprend en outre un module de correction capable d'estimer une correction à appliquer à la valeur de quantité de carburant à injecter tardivement. Ce module comporte une cartographie mémorisée de la température en amont du catalyseur en régime stabilisé, en fonction du point de fonctionnement du moteur et des cartographies mémorisées de grandeurs représentatives de l' évolution dynamique du processus d' oxydation catalytique, en fonction du point de fonctionnement du moteur. Des moyens sont également prévus pour ajouter ladite correction à la valeur de quantité de carburant à injecter tardivement, fournie par le régulateur.The device further comprises a correction module capable of estimating a correction to be applied to the fuel quantity value to be injected late. This module comprises a memorized map of the temperature upstream of the catalyst in steady state, as a function of the operating point of the engine and the memorized maps of quantities representative of the dynamic evolution of the catalytic oxidation process, as a function of the operating point. of the motor. Means are also provided for adding said correction to the fuel quantity value to be injected late, provided by the regulator.
Ainsi, il devient possible d' obtenir une meilleure régulation de la quantité de carburant à injecter tardivement pendant les phases transitoires correspondant par exemple à de fortes variations des paramètres de fonctionnement du moteur pendant des intervalles de temps courts. Les dépassements de valeur de consigne sont alors mieux maîtrisés lors de conditions de roulage instables et la rapidité de réponse de la régulation est améliorée lors de phases de roulage stables. Dans un mode de réalisation, le module de correction comprend une cartographie mémorisée d'un premier gain de valeurs de température en aval et en amont du catalyseur, en fonction du point de fonctionnement du moteur, et une cartographie mémorisée d'un premier temps de réponse du catalyseur, en fonction du point de fonctionnement du moteur. Le module de correction peut également comprendre une cartographie mémorisée d'un deuxième gain de valeurs de quantité de carburant inj ecté tardivement et de température en aval du catalyseur, en fonction du point de fonctionnement du moteur, et une cartographie mémorisée d'un deuxième temps de réponse du catalyseur, en fonction du point de fonctionnement du moteur.Thus, it becomes possible to obtain a better regulation of the quantity of fuel to be injected late during the transient phases corresponding, for example, to large variations in the operating parameters of the engine during short time intervals. The setpoint overruns are then better controlled during unstable driving conditions and the speed of response of the control is improved during stable driving phases. In one embodiment, the correction module comprises a stored map of a first gain of temperature values downstream and upstream of the catalyst, as a function of the operating point of the engine, and a stored map of a first time of catalyst response, depending on the operating point of the engine. The correction module may also include a stored map of a second gain of fuel quantity values injected late and temperature downstream of the catalyst, depending on the operating point of the engine, and a memorized map of a second time. catalyst response, depending on the operating point of the engine.
Le module de correction comprend de préférence des moyens de filtrage des gains cartographies par les temps de réponse cartographies, en fonction du point de fonctionnement du moteur. Un autre aspect de l' invention concerne un procédé de régulation d'une quantité de carburant à injecter tardivement dans les chambres de combustion d'un moteur à combustion interne de véhicule automobile du type Diesel, comprenant un filtre à particules monté dans la ligne d' échappement du moteur et un moyen d' oxydation catalytique intégré ou non dans le filtre à particules.The correction module preferably comprises means for filtering the gains mapped by the mapping response times, as a function of the operating point of the engine. Another aspect of the invention relates to a method of regulating a fuel quantity to be injected late into the combustion chambers of a diesel engine internal combustion engine, comprising a particle filter mounted in the fuel line. engine exhaust and catalytic oxidation means integrated or not in the particulate filter.
L' injection tardive est déclenchée par périodes de temps pour la régénération du filtre à particules par combustion des particules piégées dans le filtre. Selon le procédé, on régule la quantité de carburant injectée tardivement en fonction de l' écart entre la valeur de la température mesurée en aval du catalyseur et une valeur de consigne, et on applique à la valeur régulée de la quantité de carburant injectée tardivement, une correction estimée en fonction de l'évolution dynamique du processus d' oxydation pour chaque point de fonctionnement stabilisé du catalyseur.The late injection is triggered by periods of time for the regeneration of the particulate filter by combustion of particles trapped in the filter. According to the method, the quantity of fuel injected late is regulated as a function of the difference between the value of the temperature measured downstream of the catalyst and a set value, and the quantity of fuel injected late is applied to the regulated value, an estimated correction as a function of the dynamic evolution of the oxidation process for each stabilized operating point of the catalyst.
On profite ainsi de la connaissance de l' évolution dynamique du processus d'oxydation pour chaque point de fonctionnement stabilisé pour améliorer les performances de la régulation.In this way, the dynamic evolution of the oxidation process is known for each stabilized operating point in order to improve the performance of the regulation.
La correction peut, par exemple, être estimée à partir d'une cartographie mémorisée des valeurs de température en amont du catalyseur en régime stabilisé, en fonction du point de fonctionnement du moteur.The correction may, for example, be estimated from a stored map of the temperature values upstream of the catalyst in steady state, as a function of the operating point of the engine.
On tient compte de préférence également, de l' inertie thermique du catalyseur et du caractère exothermique des réactions catalytiques pour estimer la correction.The thermal inertia of the catalyst and the exothermic nature of the catalytic reactions are also preferably taken into account in estimating the correction.
L 'invention sera mieux comprise à l' étude d'un mode de réalisation pris à titre d' exemple nullement limitatif illustré par les dessins annexés sur lesquels : la figure 1 montre schématiquement la ligne d' échappement d'un moteur à combustion interne ; la figure 2 montre schématiquement les principaux éléments d'un dispositif de régulation selon l' invention et la figure 3 illustre les principaux éléments d'un module de correction utilisé dans la régulation selon l' invention. Tel que représenté sur la figure 1 , le moteur à combustion interne 1 , représenté très schématiquement, est un moteur diesel à quatre cylindres. Les chambres de combustion du moteur représentées schématiquement et référencées 2 sont alimentées en air comprimé par un conduit d'admission 3. L ' air frais admis est comprimé par un turbo compresseur 4 dont le compresseur est entraîné en rotation par une turbine traversée par les gaz d' échappement provenant de la conduite d' échappement 5. En sortie de turbine, les gaz d' échappement sont véhiculés par une ligne d' échappement 6 qui comprend un dispositif catalyseur 7 suivi d'un filtre à particules (FAP) 8. Bien que dans cet exemple, le dispositif catalyseur ait été représenté sous la forme d'un dispositif séparé du filtre à particules, on comprendra que les matériaux catalytiques puissent être disposés à l 'intérieur même du filtre à particules sans modification majeure de la présente invention. Une unité électronique de commande ECU référencée 9 assure la commande du fonctionnement du moteur 1 et permet également la commande de la régénération du filtre à particules 8. A cet effet, l'unité électronique de commande 9 qui reçoit diverses informations de paramètres de fonctionnement du moteur par les connexions 10 est capable d'émettre un signal de commande par la connexion 1 1 en vue de l' injection dans les chambres de combustion 2 d'une certaine quantité de carburant à un moment tardif c 'est-à-dire après le point mort haut, de façon à augmenter la quantité de carburant imbrûlé et la température des gaz d' échappement pour une phase de régénération du filtre à particules. Sur la figure 1 , se trouvent également représentés différents capteurs et en particulier un capteur de pression 12 monté en aval du filtre à particules 8 et un capteur de pression 13 monté en amont du filtre à particules 8. La pression différentielle ΔP entre l' amont et l' aval du filtre à particules 8 est déterminée par un module 14 qui émet un signal de pression différentielle par la connexion 15 qui amène ce signal sur l'unité électronique de commande 9. Une telle mesure de pression différentielle permet de détecter le moment où le filtre à particules est chargé en particules de suie d'une façon telle qu'une phase de régénération doit être initiée. Sur la figure 1 , on a également représenté un capteur de température 16 qui détermine la température à la sortie du catalyseur 7 Un deuxième capteur de température 17 détermine la température en amont du catalyseur 7 soit Tamont- Ces températures sont amenées par les connexions 18 et 19 à l'unité électronique de commande 9.The invention will be better understood in the study of an embodiment taken by way of nonlimiting example illustrated by the accompanying drawings in which: Figure 1 shows schematically the exhaust line of an internal combustion engine; Figure 2 shows schematically the main elements of a control device according to the invention and Figure 3 illustrates the main elements of a correction module used in the regulation according to the invention. As shown in Figure 1, the internal combustion engine 1, shown very schematically, is a four-cylinder diesel engine. The engine combustion chambers shown schematically and referenced 2 are supplied with compressed air via an intake duct 3. The fresh air admitted is compressed by a turbo compressor 4 whose compressor is rotated by a turbine traversed by the gases. Exhaust from the exhaust pipe 5. At the turbine outlet, the exhaust gas is conveyed by an exhaust line 6 which comprises a catalyst device 7 followed by a particulate filter (FAP). that in this example, the catalyst device has been shown as a device separate from the particulate filter, it will be appreciated that the catalytic materials may be disposed within the particulate filter without major modification of the present invention. An ECU electronic control unit referenced 9 provides the control of the operation of the engine 1 and also allows the control of the regeneration of the particle filter 8. For this purpose, the electronic control unit 9 which receives various information of operating parameters of the The motor 10 is capable of emitting a control signal via the connection 11 for the injection into the combustion chambers 2 of a certain quantity of fuel at a late moment, that is to say after the top dead center, so as to increase the amount of unburned fuel and the temperature of the exhaust gas for a regeneration phase of the particulate filter. FIG. 1 also shows various sensors and in particular a pressure sensor 12 mounted downstream of the particulate filter 8 and a pressure sensor 13 mounted upstream of the particulate filter 8. The differential pressure ΔP between the upstream and the downstream of the particle filter 8 is determined by a module 14 which emits a differential pressure signal through the connection 15 which brings this signal to the electronic control unit 9. Such a differential pressure measurement makes it possible to detect the moment where the particulate filter is loaded with soot particles in such a way that a regeneration phase must be initiated. FIG. 1 also shows a temperature sensor 16 which determines the temperature at the outlet of the catalyst 7. A second temperature sensor 17 determines the temperature upstream of the catalyst 7, ie, T am. These temperatures are brought by the connections. 18 and 19 to the electronic control unit 9.
Les principaux éléments de la régulation sont illustrés sur la figure 2 où l' on retrouve les mêmes éléments portant les mêmes références et notamment le moteur 1 et l'unité électronique de commande 9 ainsi que le capteur 16 déterminant la température Ts à la sortie du dispositif catalyseur 7.The main elements of the regulation are illustrated in FIG. 2, where there are the same elements bearing the same references and in particular the motor 1 and the electronic control unit 9 as well as the sensor 16 determining the temperature T s at the output. of the catalyst device 7.
La régulation comprend essentiellement un régulateur 20, qui est ici à titre d' exemple un régulateur du type proportionnel intégral dérivé (PID). La grandeur à réguler est l' écart ε qui est amené à l' entrée du régulateur 20 et qui correspond à la différence entre une température de consigne Tcons et la température Ts mesurée à la sortie du dispositif catalyseur qui est amenée sur l' entrée négative d'un comparateur 21 lequel reçoit sur son entrée positive la valeur de la température de consigne Tcons.The control essentially comprises a regulator 20, which is here by way of example a regulator of the proportional integral derivative type (PID). The quantity to be regulated is the difference ε which is fed to the input of the regulator 20 and which corresponds to the difference between a set temperature T cons and the temperature T s measured at the outlet of the catalyst device which is fed to the negative input of a comparator 21 which receives on its positive input the value of the set temperature T cons .
Conformément à l' invention, le dispositif de régulation comprend en outre un module de correction 22 noté COR sur la figure 2 qui reçoit sur son entrée la valeur de la température mesurée en amont du dispositif catalyseur c'est-à-dire Tamont provenant du capteur 17 et qui est capable d' émettre une valeur de correction Cor qui est ajoutée dans l' additionneur 23 à la valeur de la quantité de carburant à injecter qui est déterminée par le régulateur 20. De cette manière, la quantité de carburant à injecter tardivement et qui est amenée à l'entrée de l'unité électronique de commande 9 a été dûment corrigée par la valeur de correction établie par le module de correction 22.According to the invention, the regulation device further comprises a correction module 22 denoted COR in FIG. 2 which receives on its input the value of the temperature measured upstream of the catalyst device, that is to say T am. from the sensor 17 and which is capable of transmitting a correction value C or which is added in the adder 23 to the value of the quantity of fuel to be injected which is determined by the regulator 20. In this way, the amount of late injection fuel which is fed to the input of the electronic control unit 9 has been duly corrected by the correction value established by the correction module 22.
La figure 3 illustre de manière plus précise les principaux éléments du module de correction 22. Une cartographie mémorisée 24 en fonction du régime de rotation du moteur noté N et du couple moteur noté C fournit une valeur de température en amont du dispositif catalyseur Tamont en régime stabilisé pour différents points de fonctionnement du moteur. Cette valeur attendue issue de la cartographie 24 est amenée sur l' entrée négative d'un comparateur 25. Le comparateur 25 reçoit également sur son entrée positive la température amont Tamont telle que mesurée par le capteur 17. Le comparateur 25 établit donc un écart ΔTamont qui tient compte du point de fonctionnement du moteur en régime stabilisé. Afin de tenir compte également de l' inertie thermique du dispositif catalyseur 7 et des réactions catalytiques exothermiques qui augmentent la température des gaz d' échappement traversant le catalyseur 7, on applique un gain à la première correction ainsi obtenue. A cet effet, le module de correction 22 comprend une cartographie 26 en fonction du point de fonctionnement du moteur représenté par le régime de rotation N et le couple moteur C, cette cartographie donnant pour chaque point de fonctionnement du moteur en régime stabilisé la valeur d'un gain Ki qui correspond au rapport entre la température de sortie du dispositif catalyseur 7 Ts à la température en amont du catalyseur 7 Tamont soit : Ki = _TS. FIG. 3 more precisely illustrates the main elements of the correction module 22. A memorized map 24 as a function of the engine rotation speed denoted N and the engine torque denoted C provides a temperature value upstream of the catalyst device T am have in steady state for different operating points of the engine. This expected value from mapping 24 is brought to the input The comparator 25 also receives on its positive input the upstream temperature T am as measured by the sensor 17. The comparator 25 thus establishes an upstream ΔT deviation which takes into account the operating point of the engine in steady state. stabilized. In order also to take into account the thermal inertia of the catalyst device 7 and the exothermic catalytic reactions which increase the temperature of the exhaust gases passing through the catalyst 7, a gain is applied to the first correction thus obtained. For this purpose, the correction module 22 comprises a map 26 as a function of the operating point of the engine represented by the rotation speed N and the engine torque C, this map giving for each operating point of the engine in steady state the value of the engine. a gain Ki which corresponds to the ratio between the outlet temperature of the catalyst device 7 Ts at the temperature upstream of the catalyst 7 T am have either Ki = TSTS .
1 amont1 upstream
La valeur de ce gain est en outre filtrée dans le filtre 27 noté F l au moyen d'un temps de réponse ti qui tient compte de la dynamique de fonctionnement du dispositif catalyseur. Ce temps de réponse ti est déterminé en fonction du point de fonctionnement du moteur par une cartographie 28 en fonction du régime de rotation du moteur N et du couple moteur C.The value of this gain is further filtered in the filter 27 noted F1 by means of a response time ti which takes into account the operating dynamics of the catalyst device. This response time t i is determined as a function of the operating point of the engine by a map 28 as a function of the rotation speed of the engine N and the engine torque C.
On obtient l' erreur sur la température Ts en sortie du dispositif catalyseur, erreur qui est amenée sur un module de traitement 29 qui reçoit également l' écart sur la température amont ΔTamont. En sortie de ce module de traitement 29, apparaît ainsi la correction ΔTS à appliquer sur la température de sortie Ts The error is obtained on the temperature T s at the outlet of the catalyst device, which error is brought to a treatment module 29 which also receives the difference on the upstream upstream temperature ΔT. At the output of this processing module 29, thus appears the correction ΔT S to be applied to the outlet temperature T s
Le module de correction 22 comporte encore un moyen pour établir une correction sur la quantité de carburant à injecter pour atteindre la température de consigne. A cet effet, une cartographie 30 permet la détermination d'un deuxième gain K2 en fonction du point de fonctionnement du moteur, c' est-à-dire du régime de rotation du moteur N et du couple C . La valeur de ce gain K2 correspond à la quantité de carburant injectée Qpost divisé par la valeur de la température de sortie Ts du catalyseur soit :The correction module 22 also comprises a means for establishing a correction on the quantity of fuel to be injected to reach the set temperature. For this purpose, a map 30 makes it possible to determine a second gain K 2 as a function of the operating point of the engine, that is to say the rotation speed of the motor N and the torque C. The value of this gain K 2 corresponds to the amount of fuel injected Q pos t divided by the value of the outlet temperature T s of the catalyst is:
K2 = Qpost T8. Ce gain fait l'objet d'un filtrage dans le filtre 31 noté F2 au moyen d'un temps t2 de réponse du dispositif catalyseur 7, déterminé en fonction du point de fonctionnement instantané du moteur en régime stabilisé au moyen d'une cartographie 32 fonction du régime moteur N et du couple moteur C. Le temps de réponse t2 résultant de cette cartographie est amené à l' entrée du filtre 31 de façon à obtenir un gain filtré qui est amené à un module de traitement 33 recevant également la correction portant sur la température de sortie du dispositif catalyseur. Le module de traitement 33 détermine alors la valeur de correction Cor qui doit être appliquée à la quantité de carburant à injecter. On notera que les gains Ki et K2 et les temps de réponse ti et t2 sont tous issus de cartographies établies en régime statique et dépendent tous du point de fonctionnement du moteur en régime stabilisé. On a donc ainsi bénéficié de la connaissance du fonctionnement du dispositif catalyseur en régime stabilisé pour établir une correction qui peut alors être ajoutée à la valeur de la quantité de carburant à injecter telle que déterminée par le régulateur 20. L ' ajout de cette valeur de correction permet l'obtention d'une meilleure régulation de la température en sortie du dispositif catalyseur pendant les modes transitoires, correspondant par exemple à de fortes variations des paramètres moteur pendant des intervalles de temps relativement courts. Ainsi les dépassements de consigne sont parfaitement maîtrisés lors de conditions de roulage instables du véhicule. De plus, la rapidité de la régulation lors de phases de roulage stables se trouve améliorée. K 2 = Qpost T 8 . This gain is the subject of a filtering in the filter 31 noted F2 by means of a response time t 2 of the catalyst device 7, determined as a function of the instantaneous operating point of the engine in steady state by means of a mapping The response time t 2 resulting from this mapping is brought to the input of the filter 31 so as to obtain a filtered gain which is fed to a processing module 33 also receiving the signal. correction relating to the outlet temperature of the catalyst device. The processing module 33 then determines the correction value Cor which must be applied to the quantity of fuel to be injected. It will be noted that the gains K 1 and K 2 and the response times t 1 and t 2 all come from mappings established under static conditions and all depend on the operating point of the engine under steady state conditions. Thus, we have benefited from the knowledge of the operation of the catalyst device in steady state to establish a correction which can then be added to the value of the quantity of fuel to be injected as determined by the regulator 20. The addition of this value of correction makes it possible to obtain better regulation of the temperature at the outlet of the catalyst device during the transient modes, corresponding, for example, to large variations of the motor parameters during relatively short time intervals. Thus the setpoint overruns are perfectly controlled during unstable vehicle running conditions. In addition, the speed of regulation during stable rolling phases is improved.

Claims

REVENDICATIONS
1. Dispositif de régulation d'une quantité de carburant à injecter tardivement dans les chambres de combustion d'un moteur à combustion interne ( 1 ) de véhicule automobile du type Diesel, comprenant un filtre à particules (8) monté dans la ligne d' échappement du moteur et un moyen d' oxydation catalytique (7) intégré ou non dans le filtre à particules, ladite injection tardive étant déclenchée par périodes de temps pour la régénération du filtre à particules par combustion des particules piégées dans le filtre, comprenant des capteurs ( 17, 16) de la température en amont et en aval du moyen d'oxydation catalytique et un régulateur (20) recevant l' écart entre la valeur de la température (Ts) mesurée en aval du catalyseur et une valeur de consigne (Tcons), le régulateur étant capable de fournir une valeur de quantité de carburant à injecter tardivement, caractérisé par le fait qu' il comprend en outre un module de correction (22) capable d'estimer une correction à appliquer à la valeur de quantité de carburant à injecter tardivement, ledit module comportant une cartographie mémorisée (24) de la température en amont du catalyseur en régime stabilisé, en fonction du point de fonctionnement du moteur et des cartographies mémorisées (26-32) de grandeurs représentatives de l'évolution dynamique du processus d' oxydation catalytique, en fonction du point de fonctionnement du moteur, et des moyens pour ajouter ladite correction à la valeur de quantité de carburant à inj ecter tardivement, fournie par le régulateur.1. Device for regulating a fuel quantity to be injected late into the combustion chambers of an internal combustion engine (1) of a diesel type motor vehicle, comprising a particulate filter (8) mounted in the line of exhaust of the engine and a catalytic oxidation means (7) integrated or not into the particulate filter, said late injection being triggered by periods of time for the regeneration of the particulate filter by combustion of the particles trapped in the filter, comprising sensors (17, 16) of the temperature upstream and downstream of the catalytic oxidation means and a regulator (20) receiving the difference between the value of the temperature (T s ) measured downstream of the catalyst and a set value ( T cons ), the regulator being able to provide a value of fuel quantity to be injected late, characterized in that it further comprises a correction module (22) capable of estimating a a correction to be applied to the value of fuel quantity to be injected late, said module comprising a memorized map (24) of the temperature upstream of the catalyst in steady state, as a function of the operating point of the engine and the stored maps (26- 32) representative quantities of the dynamic evolution of the catalytic oxidation process, as a function of the operating point of the engine, and means for adding said correction to the fuel quantity value to be injected late, provided by the regulator.
2. Dispositif selon la revendication 1 dans lequel le module de correction comprend une cartographie mémorisée (26) d'un premier gain de valeurs de température en aval et en amont du catalyseur, en fonction du point de fonctionnement du moteur, et une cartographie mémorisée (28) d'un premier temps de réponse du catalyseur, en fonction du point de fonctionnement du moteur. 2. Device according to claim 1 wherein the correction module comprises a stored map (26) of a first gain of temperature values downstream and upstream of the catalyst, depending on the operating point of the engine, and a stored map (28) a first catalyst response time, depending on the operating point of the engine.
3. Dispositif selon l'une des revendications 1 ou 2 dans lequel le module de correction comprend une cartographie mémorisée (30) d'un deuxième gain de valeurs de quantité de carburant injecté tardivement et de température en aval du catalyseur, en fonction du point de fonctionnement du moteur, et une cartographie mémorisée (32) d'un deuxième temps de réponse du catalyseur, en fonction du point de fonctionnement du moteur.3. Device according to one of claims 1 or 2 wherein the correction module comprises a stored map (30) of a second gain of fuel quantity values injected late and temperature downstream of the catalyst, depending on the point of operating the engine, and a stored map (32) of a second catalyst response time, depending on the operating point of the engine.
4. Dispositif selon l'une des revendications 2 ou 3 dans lequel le module de correction comprend des moyens de filtrage (27, 31 ) des gains cartographiés par les temps de réponse cartographiés, en fonction du point de fonctionnement du moteur.4. Device according to one of claims 2 or 3 wherein the correction module comprises filtering means (27, 31) gains mapped by the mapped response times, depending on the operating point of the engine.
5. Procédé de régulation d'une quantité de carburant à injecter tardivement dans les chambres de combustion d'un moteur à combustion interne de véhicule automobile du type Diesel, comprenant un filtre à particules monté dans la ligne d'échappement du moteur et un moyen d' oxydation catalytique intégré ou non dans le filtre à particules, ladite injection tardive étant déclenchée par périodes de temps pour la régénération du filtre à particules par combustion des particules piégées dans le filtre, dans lequel on régule la quantité de carburant injectée tardivement en fonction de l' écart entre la valeur de la température mesurée en aval du catalyseur et une valeur de consigne, caractérisé par le fait qu'on applique à la valeur régulée de la quantité de carburant injectée tardivement, une correction estimée en fonction de l'évolution dynamique du processus d' oxydation pour chaque point de fonctionnement stabilisé du catalyseur.5. A method of regulating a fuel quantity to be injected late in the combustion chambers of a diesel engine internal combustion engine, comprising a particulate filter mounted in the exhaust line of the engine and means catalytic oxidation integrated or not in the particulate filter, said late injection being triggered by periods of time for the regeneration of the particulate filter by combustion of particles trapped in the filter, wherein the amount of fuel injected late is regulated according to the difference between the value of the temperature measured downstream of the catalyst and a set value, characterized in that the applied value to the regulated value of the quantity of fuel injected late, an estimated correction according to the evolution dynamics of the oxidation process for each stabilized operating point of the catalyst.
6. Procédé selon la revendication 5 dans lequel la correction est estimée à partir d'une cartographie mémorisée des valeurs de température en amont du catalyseur en régime stabilisé, en fonction du point de fonctionnement du moteur.6. The method of claim 5 wherein the correction is estimated from a stored map of the temperature values upstream of the catalyst in steady state, depending on the operating point of the engine.
7. Procédé selon l'une des revendications 5 ou 6 dans lequel on tient compte de l' inertie thermique du catalyseur et du caractère exothermique des réactions catalytiques pour estimer la correction. 7. Method according to one of claims 5 or 6 wherein taking into account the thermal inertia of the catalyst and the exothermic nature of the catalytic reactions to estimate the correction.
PCT/FR2007/052209 2006-10-25 2007-10-19 Method and device for regulating an amount of fuel to be injected late in order to regenerate an internal combustion engine particulate filter WO2008050049A1 (en)

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FR0654519 2006-10-25
FR0654519A FR2907846B1 (en) 2006-10-25 2006-10-25 DEVICE AND METHOD FOR CONTROLLING A QUANTITY OF FUEL TO BE INJECTED LATE FOR THE REGENERATION OF A PARTICLE FILTER OF AN INTERNAL COMBUSTION ENGINE

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CN113356983A (en) * 2020-03-04 2021-09-07 德尔福汽车***卢森堡有限公司 Method for monitoring an exhaust gas aftertreatment device

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CN104454085B (en) * 2014-10-29 2017-03-01 凯龙高科技股份有限公司 A kind of combustion-supporting regeneration temperature control method of DPF diesel particulate filtration system oil spout

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DE10033159A1 (en) * 2000-07-07 2002-01-17 Daimler Chrysler Ag IC engines esp. for motor vehicles with fuel after-injection for particle filter regeneration regulated dependent upon exhaust temperature in front of filter
FR2864992A1 (en) * 2004-01-14 2005-07-15 Bosch Gmbh Robert METHOD AND APPARATUS FOR CONTROLLING THE EXHAUST GAS TEMPERATURE REGULATION OF AN INTERNAL COMBUSTION ENGINE

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Publication number Priority date Publication date Assignee Title
DE10033159A1 (en) * 2000-07-07 2002-01-17 Daimler Chrysler Ag IC engines esp. for motor vehicles with fuel after-injection for particle filter regeneration regulated dependent upon exhaust temperature in front of filter
FR2864992A1 (en) * 2004-01-14 2005-07-15 Bosch Gmbh Robert METHOD AND APPARATUS FOR CONTROLLING THE EXHAUST GAS TEMPERATURE REGULATION OF AN INTERNAL COMBUSTION ENGINE

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Publication number Priority date Publication date Assignee Title
CN113356983A (en) * 2020-03-04 2021-09-07 德尔福汽车***卢森堡有限公司 Method for monitoring an exhaust gas aftertreatment device
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