EP1809878A1 - Device for controlling the operating state of a catalytic converter of an exhaust line pertaining to an internal combustion engine, and engine comprising one such device - Google Patents

Device for controlling the operating state of a catalytic converter of an exhaust line pertaining to an internal combustion engine, and engine comprising one such device

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Publication number
EP1809878A1
EP1809878A1 EP05816061A EP05816061A EP1809878A1 EP 1809878 A1 EP1809878 A1 EP 1809878A1 EP 05816061 A EP05816061 A EP 05816061A EP 05816061 A EP05816061 A EP 05816061A EP 1809878 A1 EP1809878 A1 EP 1809878A1
Authority
EP
European Patent Office
Prior art keywords
catalytic converter
temperature
converter
engine
upstream
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP05816061A
Other languages
German (de)
French (fr)
Inventor
Benoît Thuault
Helene Biales
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Renault SAS
Original Assignee
Renault SAS
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Renault SAS filed Critical Renault SAS
Publication of EP1809878A1 publication Critical patent/EP1809878A1/en
Withdrawn legal-status Critical Current

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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
    • F01N11/00—Monitoring or diagnostic devices for exhaust-gas treatment apparatus, e.g. for catalytic activity
    • 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
    • F01N13/00—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00
    • F01N13/009—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00 having two or more separate purifying devices arranged in series
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/24—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by constructional aspects of converting apparatus
    • F01N3/36—Arrangements for supply of additional fuel
    • 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
    • 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
    • F01N9/00—Electrical control of exhaust gas treating apparatus
    • F01N9/007—Storing data relevant to operation of exhaust systems for later retrieval and analysis, e.g. to research exhaust system malfunctions
    • 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
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2550/00—Monitoring or diagnosing the deterioration of exhaust systems
    • F01N2550/02—Catalytic activity of catalytic converters
    • 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
    • F01N2560/00—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics
    • F01N2560/06—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics the means being a temperature sensor
    • 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
    • F01N2560/00—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics
    • F01N2560/14—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics having more than one sensor of one kind
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B37/00—Engines characterised by provision of pumps driven at least for part of the time by exhaust
    • 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 relates generally to the treatment of the exhaust gases of an internal combustion engine, for example a motor vehicle and, in particular, an internal combustion engine operating in 5 poor mixture, especially a diesel or gasoline engine.
  • the invention relates more particularly to a device for controlling the operating state of a catalytic converter implanted in an exhaust line of an internal combustion engine, intended to control that said catalytic converter is always able to ensure its proper performance. function. It also relates to an internal combustion engine for a motor vehicle comprising an exhaust line equipped with at least one catalytic converter and such a device for monitoring the operating state of said converter.
  • motor vehicles are often provided with a catalytic converter disposed in the exhaust line of the engine, for oxidizing the reducing molecules that are carbon monoxide (CO) and unburned hydrocarbons (HC).
  • a catalytic converter disposed in the exhaust line of the engine, for oxidizing the reducing molecules that are carbon monoxide (CO) and unburned hydrocarbons (HC).
  • Such a catalytic converter may be an oxidation catalyst, a catalyzed particle filter or a nitrogen oxides trap (NOx);
  • Some motor vehicles comprise in their exhaust line several different catalytic converters arranged in series.
  • the motor vehicles are moreover generally provided with a device for checking the operating state of the catalytic converter, able, on the one hand, to control the correct operation of the converter and, secondly, to report any malfunction to the driver.
  • the aging of the catalytic converter causes a reduction in the conversion efficiency of unburned hydrocarbons and carbon monoxide, due inter alia to a reduction in the active surface of treatment of the pollutants in the converter. an increase in the thermal initiation temperature of the oxidation reactions produced within the latter, that is to say the temperature from which the conversion efficiency is greater than or equal to 50%.
  • a device comprising means for determining the temperature prevailing upstream of the catalytic converter, means for injecting fuel into a fuel cell. or several cylinders of the engine during their expansion phase at a time at which the temperature of the exhaust gas upstream of the catalytic converter corresponds to the ignition temperature of a catalytic converter having normal operation, and means of controlling the quantity of heat released by the reaction produced in the catalytic converter under the effect of this post-fuel injection.
  • Such a control device although relatively effective, however, has several disadvantages.
  • the present invention proposes a device for monitoring the operating state of a catalytic converter of an exhaust line of an internal combustion engine, comprising means for determining the prevailing temperature. upstream of the catalytic converter, means for supplying fuel into the exhaust line of the engine at a time at which the temperature of the exhaust gas upstream of the catalytic converter corresponds to the ignition temperature of a catalytic converter having a normal operation and means for controlling the amount of heat generated by the reaction produced in the catalytic converter under the effect of this fuel supply, characterized in that said supply means comprise a dedicated fuel supply system arranged in the exhaust line of the engine upstream of the catalytic converter to be controlled.
  • the dedicated fuel supply system is an injection system
  • the dedicated fuel supply system is a vaporization system; a specific fuel injection system is provided in at least one engine cylinder for bringing the temperature of the exhaust gases upstream of the catalytic converter to said temperature; of the latter, whatever the driving conditions of the motor vehicle, this specific fuel injection system being coupled to said dedicated fuel supply system,
  • the means for determining the temperature of the gases upstream of the catalytic converter comprise a means for measuring said gas temperature
  • the means for determining the temperature of the gases upstream of the catalytic converter comprise means for measuring operating parameters of the engine and / or the catalytic converter and a model thermal exhaust gas adapted to determine the temperature of the gas upstream of the catalytic converter according to operating parameters of the engine and / or the catalytic converter,
  • the means for controlling the amount of heat generated by the reaction produced in the catalytic converter comprise means for measuring the temperature of the exhaust gases downstream of said converter and means for comparing the temperature of the gases downstream of the converter; with a threshold value for detecting a malfunction, and
  • this computer comprises a computer providing the control of the operation of the engine and the control of the operation of the catalytic converter, this computer comprising said comparison means and storage means in which are stored a set of threshold values each associated with one of the parameters of operation of the engine and / or the catalytic converter and a set of thermal initiation temperature values of the catalytic converter as a function of the flow of exhaust gas in said converter, the threshold value supplied to the comparison means being extracted from the storage means according to the measured operating parameters
  • the invention also relates to an internal combustion engine for a motor vehicle comprising an exhaust line equipped with at least one catalytic converter and a device for controlling the operating state of said catalytic converter as defined above.
  • FIG. 1 is a schematic view of a first embodiment of an internal combustion engine comprising in its exhaust line a catalytic converter associated with a control device according to the invention
  • FIG. 2 is a diagrammatic view. of a second embodiment of an internal combustion engine comprising in its exhaust line a catalytic converter associated with a control device according to the invention
  • FIG. 3 is a schematic view of a third embodiment of an internal combustion engine comprising in its exhaust line a catalytic converter associated with a control device according to the invention
  • FIG. 4A is a schematic view of a first embodiment of the dedicated power supply system of the control device according to the invention
  • FIG. 4B is a schematic view of a second embodiment of the dedicated system of FIG. supply of the control device according to the invention
  • FIG. 5 shows curves illustrating the variation of the conversion efficiency of carbon monoxide CO as a function of the inlet temperature of the converter, respectively for a new converter and for an aged converter
  • FIG. 6 shows curves illustrating the variation; the conversion efficiency of unburned hydrocarbons HC as a function of the inlet temperature of the converter, respectively for a new converter and for an aged converter
  • FIG. 7 shows curves illustrating the method implemented by the control device according to the invention for controlling the operating state of a catalytic converter of an internal combustion engine
  • FIG. 8 is an algorithm. operation of the control device according to the invention
  • FIGS. 1 to 3 show schematically the general structure of three variants of an internal combustion engine 10, ICI a diesel engine, of a motor vehicle
  • This engine 10 comprises a combustion chamber 11 provided with cylinders
  • the cylinders of the combustion chamber 11 are supplied with cooling air by a cooler 18 associated with an intake distributor (not shown), itself fed by a pipe C provided with the input of an air filter 12 FOLLOWING a flowmeter 13 and a turbocharger 14 of supercharging the engine with air
  • An exhaust manifold (not shown) recovers the exhaust gas from the combustion and discharges the latter to the outside by an exhaust line E via the turbocharger 14
  • a recirculation circuit R exhaust gas recovers a part of the exhaust gases and reinjects them into the intake manifold so as to limit the amount of nitrogen oxides produced by the combustion while avoiding the formation of smoke in the exhaust gas
  • the recirculation circuit R essentially comprises a valve 17 for regulating the recirculated exhaust gas flow preceded by a cooler 16 fed by a bypass 15
  • this comprises two catalytic converters in series, for example a catalyst SUIVI of a particulate filter or a Nox trap.
  • particulate filter or the Nox trap precedes the catalyst
  • the catalyst essentially ensures the post-treatment of the exhaust gases by oxidation of the reducing molecules, which are carbon monoxide (CO) and unburned hydrocarbons (HC).
  • the particulate filter or the Nox trap 31 ensures the post-treatment particles and Nox
  • the catalyst 30 has a conventional structure within the reach of those skilled in the art and it will not be described in detail
  • the monolith forming part of the catalyst 30 is IC1 integrated in the particulate filter or the Nox trap 31, in order to achieve a coupling between the aftertreatment of the exhaust gases by oxidation of carbon monoxide and unburned hydrocarbons (HC) after particle and Nox post-treatment
  • the engine 10 is associated with an on-board computer 27 essentially ensuring the control of the operation of the engine 10, in particular the adjustment of its operating parameters, as well as the control of the operation of at least one of the converters 30.
  • the computer 27 is connected to the main functional elements of the engine, these connections being represented by dashed lines.
  • the computer 27 comprises storage means in which are stored a set of data obtained by prior learning corresponding in particular to malfunction detection threshold values, and, if appropriate, temperature values upstream of the catalytic converter to be controlled according to the temperature prevailing downstream, and software control means of the amount of heat released by the chemical reaction generated by the post-injection within the catalytic converter by comparison with threshold values
  • the engine 10 comprises, as a device for controlling the operating state of one of the converters 30, 31, means 24 for determining the temperature prevailing upstream of the corresponding catalytic converter 30, 31, means for supplying fuel into the exhaust line E of the engine at the instant at which the temperature of the exhaust gas upstream of the catalytic converter 30,31 corresponds to the starting temperature of a converter having normal operation and control means 25,26 of the amount of heat generated by the reaction produced in the catalytic converter 30,31 under the effect of this fuel supply
  • said delivery means comprise a dedicated fuel supply system disposed downstream of the combustion chamber 11, in the exhaust line E of the engine 10, upstream of the converter catalytic 30, 31 to be controlled
  • this dedicated feed system is placed just upstream of the catalyst to be controlled.
  • this dedicated supply system is placed just upstream of the particulate filter or the Nox trap 31 to be controlled.
  • this dedicated supply system 20 is placed upstream of the turbocompressor 14 in order to carry out the control of the catalyst 30
  • the dedicated power system 20 is connected to the computer 27 which ensures its control
  • means are provided for supplying fuel directly from the fuel tank of the motor vehicle to said dedicated supply system.
  • These means comprise a pump 28 which supplies the fuel via line A to the dedicated supply system 20.
  • the dedicated fuel supply system is an injection system controlled directly by the computer.
  • the dedicated fuel supply system is a vaporization system 20 which comoorte a vaporization chamber 22 immersed in the exhaust pipe E, this vaporization chamber 22 being connected to a fuel heating system 21 supplied by said pump 28 driven by the computer 27
  • the means for determining the temperature of the gases upstream of the catalytic converter 30, 31 concerned have a means for measuring the temperature of the gases.
  • a sensor is provided. 24 for measuring the temperature of the exhaust gas upstream of the converter 30, a sensor 25 for measuring the temperature of the exhaust gas downstream of the converter 30 and upstream of the converter 31, and a sensor 26 for measuring the temperature of the exhaust gas downstream of the converter 31
  • the sensors 24,25,26 are connected to the computer 27
  • the temperature measurement sensor 24 is an optional element, the temperature prevailing upstream of the converter 30 can be estimated, either from a mathematical model and from operating parameters of the engine and / or the catalytic converter concerned, either to from the temperature prevailing downstream of the converter concerned outside the post-injection phase
  • the temperature measurements provided by the sensors 24, 25, 26 are processed by the calculation means of the calculator 27 so as to determine the rise temperature rise of the converter 30, 31 control to detect a decrease in subsequent efficiency of conversion of unburned hydrocarbons (HC) and carbon monoxide (CO)
  • FIG. 6 shows the evolution of the conversion efficiency of unburned HC hydrocarbons as a function of the inlet temperature of the monolith, respectively for a new converter (curve C) and for an aged converter (curve D), it is also noted that the aging of the converter is accompanied by a relatively large rise in the starting temperature of the converter
  • the computer carries out a control of the ignition temperature of the converter to be tested and / or a control, for an operating temperature corresponding to the ignition temperature of the converter.
  • a converter the amount of heat released by the chemical oxidation reaction implemented in the converter
  • the means for controlling the amount of heat generated by the reaction produced in the catalytic converter 30,31 comprise means of measuring the temperature of the exhaust gas downstream of said converter, ICI the sensors 25,26 and comparison means provided in the computer 27 the gas temperature downstream of the catalytic converter concerned with a threshold value for detecting a malfunction
  • a specific system for injecting fuel into at least one engine cylinder to bring the temperature of the exhaust gas upstream of the catalytic converter to said temperature of the engine. ignition of the latter whatever the driving conditions of the motor vehicle, this specific fuel injection system being coupled to said dedicated fuel supply system.
  • the computer 27 When the computer 27 receives a diagnostic request from the converter 30, it measures by the sensor 24 the temperature of the exhaust gas upstream of the converter 30 and verifies that it is equal to the ignition temperature of the converter 30 for driving conditions given
  • the computer activates the specific fuel injection system in the combustion chamber of the engine so as to bring it to this priming temperature
  • the computer 27 then proceeds to an excitation of the catalytic converter 30 by injection or vaporization of a determined quantity of fuel in the exhaust line E upstream of the converter 30. For this, the computer 27 controls the injector 20, which is supplied by the pump 28
  • FIG. 7 shows the evolution as a function of time of the temperature upstream of a new converter (curve E), the temperature downstream of a new converter (curve F), the temperature upstream of an aged converter (curve G) and the temperature downstream of an aged converter (curve H) It will be noted from these curves that the amount of heat Q1 heat released by the oxidation chemical reaction in the converter because of the post-injection, for a new converter, is much greater than the amount of heat Q2 released during the oxidation chemical reaction within an aged converter
  • the computer 27 analyzes the start-up time of the converter 30 as well as the quantity of heat released by the reaction implemented in the converter 30, for example by comparison with a threshold value below which one considers that the converter is defective
  • the calculator 27 proceeds with a calculation of the difference between the temperature downstream of the converter and the temperature upstream of the converter, then it carries out a comparison of the difference thus calculated with a threshold value of detection of a malfunction, reflecting the aging of the catalyst If a malfunction is detected, it is signaled to the driver by lighting a warning light on the dashboard of the motor vehicle, otherwise the computer 27 cuts off the dedicated post-injection system 20 in the exhaust line
  • the threshold value used to check the correct functioning of the converter corresponds to a quantity of heat released by a converter whose aging, and thus the conversion capacity, is at the limit of eligibility.
  • the computer 27 calculates the temperature rise time of the tested converter 30 and compares it with a threshold temperature rise time of a converter at the limit of eligibility. The rise time is below the given threshold. and the converter is considered as integrates or it is higher than this threshold and a malfunction of the converter is detected Such a malfunction is then reported to the driver through the ignition of a light on the dashboard of the motor vehicle If no malfunction n is detected the computer 27 cuts the dedicated system 20 of post-injection in the line the exhaust As shown by the algorithm of FIG. 8, the tests of the amount of heat and of the initiation time can be coupled by the computer 27 in order to improve the diagnosis of the converter in question.
  • the computer 27 includes stored in memory, a set of threshold values each associated with specific engine operating parameters.
  • the computer 27 proceeds with an acquisition of engine operating parameters, such as, in particular, the operating speed of the engine, the pressure prevailing in the intake circuit. air, etc., which are provided by sensors of which the engine is equipped, so as to determine the operating conditions of the latter, and then extracts from the memory one or more corresponding threshold values, so as to adapt the minimum level of amount of heat or priming time permissible to the engine operating parameters.
  • engine operating parameters such as, in particular, the operating speed of the engine, the pressure prevailing in the intake circuit. air, etc., which are provided by sensors of which the engine is equipped, so as to determine the operating conditions of the latter, and then extracts from the memory one or more corresponding threshold values, so as to adapt the minimum level of amount of heat or priming time permissible to the engine operating parameters.
  • the computer 27 also comprises, stored in memory, a map in which are memorized a set of fuel flow and post-injection timing values as a function of the operating parameters of the engine, so as to optimize the arrival of hydrocarbons in the converter to be tested while it starts.
  • the injected fuel flow is within a specific range so as not to degrade the converter by excessive heat generation.
  • the computer acquires the value of the temperature of the exhaust gas upstream of the converter and then compares this temperature to a starting temperature of a new converter. As soon as this temperature is reached, it causes the post-injection.
  • the use of the specific injection system in the engine cylinders to increase the temperature of the gas upstream of the converter is optional and the computer can simply monitor this temperature until it reaches the target priming temperature.
  • the senor 24 for measuring the temperature prevailing upstream of the converter 30 is also optional.
  • the computer 27 may comprise, stored in memory, values of temperature upstream of the converter as a function of the temperature prevailing downstream and as a function of engine operating conditions
  • the computer 27 may also include a thermal model of the exhaust gas and thus perform a calculation of the upstream temperature from the operating parameters of the engine and / or the converter.
  • the present invention is not limited to the embodiments described. and represented but the person skilled in the art will be able to make any variant that fits his mind.

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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)
  • Health & Medical Sciences (AREA)
  • Toxicology (AREA)
  • Exhaust Gas After Treatment (AREA)
  • Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)

Abstract

The invention relates to a device for controlling the operating state of a catalytic converter (30,31) of an exhaust line pertaining to an internal combustion engine (10), said device comprising means for determining (25,26) the temperature upstream of the catalytic converter, means for adding fuel to the exhaust line of the engine at the moment at which the temperature of the exhaust gas upstream of the catalytic converter corresponds to the ignition temperature of a catalytic converter with a normal operation, and means for controlling the quantity of heat emitted by the reaction generated in the catalytic converter as a result of said addition of fuel. According to the invention, said addition means comprise a dedicated fuel supply system (20) arranged in the exhaust line of the engine upstream of the catalytic converter to be controlled.

Description

DISPOSITIF DE CONTRÔLE DE L'ÉTAT DE FONCTIONNEMENT D'UN CONVERTISSEUR CATLYTIQUE D'UNE LIGNE D'ÉCHAPPEMENT D'UN MOTEUR A COMBUSTION INTERNE ET MOTEUR COMPRENANT UN TEL DISPOSITIFDEVICE FOR CONTROLLING THE OPERATING STATUS OF A CATLYTIC CONVERTER OF AN EXHAUST LINE OF AN INTERNAL COMBUSTION ENGINE AND MOTOR COMPRISING SUCH A DEVICE
DOMAINE TECHNIQUE AUQUEL SE RAPPORTE L'INVENTION La présente invention concerne de manière générale le traitement des gaz d'échappement d'un moteur à combustion interne, par exemple de véhicule automobile et, en particulier, d'un moteur à combustion interne fonctionnant en 5 mélange pauvre, notamment un moteur Diesel ou à essence.TECHNICAL FIELD TO WHICH THE INVENTION RELATES The present invention relates generally to the treatment of the exhaust gases of an internal combustion engine, for example a motor vehicle and, in particular, an internal combustion engine operating in 5 poor mixture, especially a diesel or gasoline engine.
L'invention concerne plus particulièrement un dispositif de contrôle de l'état de fonctionnement d'un convertisseur catalytique implanté dans une ligne d'échappement d'un moteur à combustion interne, destiné à contrôler que ledit convertisseur catalytique est toujours apte à assurer convenablement sa fonction. 10 Elle concerne également un moteur à combustion interne pour véhicule automobile comprenant une ligne d'échappement équipée d'au moins un convertisseur catalytique et un tel dispositif de contrôle de l'état de fonctionnement dudit convertisseur.The invention relates more particularly to a device for controlling the operating state of a catalytic converter implanted in an exhaust line of an internal combustion engine, intended to control that said catalytic converter is always able to ensure its proper performance. function. It also relates to an internal combustion engine for a motor vehicle comprising an exhaust line equipped with at least one catalytic converter and such a device for monitoring the operating state of said converter.
ARRIERE-PLAN TECHNOLOGIQUEBACKGROUND
15 Les moteurs à combustion interne produisent des gaz d'échappement qui contiennent des substances polluantes, telles que les oxydes d'azote (Nox), les hydrocarbures imbrûlés (HC), le monoxyde de carbone (CO), qu'il est nécessaire de traiter avant de les évacuer dans l'atmosphère.Internal combustion engines produce exhaust gases which contain polluting substances, such as nitrogen oxides (NOx), unburnt hydrocarbons (HC), carbon monoxide (CO), which it is necessary to treat before venting into the atmosphere.
Ainsi, les véhicules automobiles sont souvent pourvus d'un convertisseur 20 catalytique disposé dans la ligne d'échappement du moteur, permettant d'oxyder les molécules réductrices que sont le monoxyde de carbone (CO) et les hydrocarbures imbrûlés (HC).Thus, motor vehicles are often provided with a catalytic converter disposed in the exhaust line of the engine, for oxidizing the reducing molecules that are carbon monoxide (CO) and unburned hydrocarbons (HC).
Un tel convertisseur catalytique peut être un catalyseur d'oxydation, un filtre à particules catalysé ou bien un piège à oxydes d'azote (Nox) ; 25 Certains véhicules automobiles comprennent dans leur ligne d'échappement plusieurs convertisseurs catalytiques différents disposés en série. Dans le but de contrôler le bon fonctionnement d'au moins un convertisseur catalytique, les véhicules automobiles sont en outre généralement pourvus d'un dispositif de contrôle de l'état de fonctionnement du convertisseur 30 catalytique, apte, d'une part, à contrôler le bon fonctionnement du convertisseur et, d'autre part, à signaler tout dysfonctionnement au conducteur. Parmi les causes de dysfonctionnement, le vieillissement du convertisseur catalytique engendre une baisse de l'efficacité de conversion des hydrocarbures imbrûlés et du monoxyde de carbone, due entre autre à une diminution de la surface active de traitement des polluants au sein du convertisseur d'où une augmentation de la température d'amorçage thermique des réactions d'oxydation produites au sein de ce dernier, c'est-à-dire la température à partir de laquelle l'efficacité de conversion est supérieure ou égale à 50%.Such a catalytic converter may be an oxidation catalyst, a catalyzed particle filter or a nitrogen oxides trap (NOx); Some motor vehicles comprise in their exhaust line several different catalytic converters arranged in series. In order to control the operation of at least one catalytic converter, the motor vehicles are moreover generally provided with a device for checking the operating state of the catalytic converter, able, on the one hand, to control the correct operation of the converter and, secondly, to report any malfunction to the driver. Among the causes of malfunction, the aging of the catalytic converter causes a reduction in the conversion efficiency of unburned hydrocarbons and carbon monoxide, due inter alia to a reduction in the active surface of treatment of the pollutants in the converter. an increase in the thermal initiation temperature of the oxidation reactions produced within the latter, that is to say the temperature from which the conversion efficiency is greater than or equal to 50%.
Pour contrôler le bon fonctionnement d'un convertisseur catalytique, on connaît du document FR 2 833 994 appartenant à la demanderesse, un dispositif comprenant des moyens de détermination de la température régnant en amont du convertisseur catalytique, des moyens d'injection de carburant dans un ou plusieurs cylindres du moteur durant leur phase de détente à instant auquel la température des gaz d'échappement en amont du convertisseur catalytique correspond à la température d'amorçage d'un convertisseur catalytique ayant un fonctionnement normal, et des moyens de contrôle de la quantité de chaleur dégagée par la réaction produite dans le convertisseur catalytique sous l'effet de cette post-injection de carburant.To check the correct operation of a catalytic converter, document FR 2,833,994 belonging to the applicant is known, a device comprising means for determining the temperature prevailing upstream of the catalytic converter, means for injecting fuel into a fuel cell. or several cylinders of the engine during their expansion phase at a time at which the temperature of the exhaust gas upstream of the catalytic converter corresponds to the ignition temperature of a catalytic converter having normal operation, and means of controlling the quantity of heat released by the reaction produced in the catalytic converter under the effect of this post-fuel injection.
Un tel dispositif de contrôle bien que relativement efficace présente cependant plusieurs inconvénients. Tout d'abord, il utilise une post-injection de carburant dans un cylindre moteur en phase de détente ce qui est susceptible de provoquer une dilution de carburant dans l'huile du moteur lorsque les jets de carburant touchent les parois des fûts des cylindres alors que le piston redescend, ce qui n'est pas souhaitable.Such a control device although relatively effective, however, has several disadvantages. First, it uses a post-injection of fuel in a motor cylinder in the expansion phase which is likely to cause a dilution of fuel in the engine oil when the fuel jets touch the walls of the barrels of the cylinders then that the piston goes down, which is not desirable.
En outre, la post-injection de carburant dans un cylindre moteur provoque la production d'une certaine quantité de CH4 non traitée par le convertisseur catalytique. Celle-ci entraîne des pénalités importantes en hydrocarbures imbrûlés sur un cycle d'homologation.In addition, the post-injection of fuel into a drive cylinder causes the production of a certain amount of untreated CH4 by the catalytic converter. This leads to significant penalties for unburned hydrocarbons on an approval cycle.
Enfin, du fait qu'il utilise une post-injection dans les cylindres moteurs, un tel dispositif de contrôle permet seulement de contrôler le fonctionnement du convertisseur catalytique situé le plus proche de la sortie de la chambre de combustion. Ainsi, lorsque le moteur comporte au moins deux convertisseurs catalytiques disposés en série dans la ligne d'échappement, le deuxième convertisseur catalytique le plus éloigné de la chambre de combustion ne peut être contrôlé par un tel dispositif de contrôle. OBJET DE L'INVENTIONFinally, because it uses a post-injection in the engine cylinders, such a control device only allows to control the operation of the catalytic converter located closest to the outlet of the combustion chamber. Thus, when the engine comprises at least two catalytic converters arranged in series in the exhaust line, the second catalytic converter furthest from the combustion chamber can not be controlled by such a control device. OBJECT OF THE INVENTION
Afin de remédier aux inconvénients précités, la présente invention propose un dispositif de contrôle de l'état de fonctionnement d'un convertisseur catalytique d'une ligne d'échappement d'un moteur à combustion interne, comprenant des moyens de détermination de la température régnant en amont du convertisseur catalytique, des moyens d'apport de carburant dans la ligne d'échappement du moteur à instant auquel la température des gaz d'échappement en amont du convertisseur catalytique correspond à la température d'amorçage d'un convertisseur catalytique ayant un fonctionnement normal et des moyens de contrôle de la quantité de chaleur dégagée par la réaction produite dans le convertisseur catalytique sous l'effet de cet apport de carburant, caractérise en ce que lesdits moyens d'apport comprennent un système dédie d'alimentation en carburant disposé dans la ligne d'échappement du moteur en amont du convertisseur catalytique a contrôler D'autres caractéristiques non limitatives et avantageuses du dispositif de contrôle selon l'invention sont les suivantesIn order to overcome the aforementioned drawbacks, the present invention proposes a device for monitoring the operating state of a catalytic converter of an exhaust line of an internal combustion engine, comprising means for determining the prevailing temperature. upstream of the catalytic converter, means for supplying fuel into the exhaust line of the engine at a time at which the temperature of the exhaust gas upstream of the catalytic converter corresponds to the ignition temperature of a catalytic converter having a normal operation and means for controlling the amount of heat generated by the reaction produced in the catalytic converter under the effect of this fuel supply, characterized in that said supply means comprise a dedicated fuel supply system arranged in the exhaust line of the engine upstream of the catalytic converter to be controlled. non-limiting and advantageous of the control device according to the invention are the following
- le système dédié d'alimentation en carburant est un système d'injection ,the dedicated fuel supply system is an injection system,
- le système dédié d'alimentation en carburant est un système de vaporisation , - il est prévu un système spécifique d'injection de carburant dans au moins un cylindre moteur pour amener la température des gaz d'échappement en amont du convertisseur catalytique à ladite température d'amorçage de ce dernier quelles que soient les conditions de roulage du véhicule automobile, ce système spécifique d'injection de carburant étant couplé audit système dédié d'alimentation en carburant ,the dedicated fuel supply system is a vaporization system; a specific fuel injection system is provided in at least one engine cylinder for bringing the temperature of the exhaust gases upstream of the catalytic converter to said temperature; of the latter, whatever the driving conditions of the motor vehicle, this specific fuel injection system being coupled to said dedicated fuel supply system,
- il est prévu des moyens pour alimenter en carburant directement à partir du réservoir de carburant du véhicule automobile ledit système dédié d'alimentation ,- there is provided means for supplying fuel directly from the fuel tank of the motor vehicle said dedicated feeding system,
- les moyens de détermination de la température des gaz en amont du convertisseur catalytique comportent un moyen de mesure de ladite température des gaz ,the means for determining the temperature of the gases upstream of the catalytic converter comprise a means for measuring said gas temperature,
- les moyens de détermination de la température des gaz en amont du convertisseur catalytique comportent des moyens de mesure de paramètres de fonctionnement du moteur et/ou du convertisseur catalytique et un modèle thermique des gaz d'échappement adapté à déterminer la température des gaz en amont du convertisseur catalytique en fonction de paramètres de fonctionnement du moteur et/ou du convertisseur catalytique ,the means for determining the temperature of the gases upstream of the catalytic converter comprise means for measuring operating parameters of the engine and / or the catalytic converter and a model thermal exhaust gas adapted to determine the temperature of the gas upstream of the catalytic converter according to operating parameters of the engine and / or the catalytic converter,
- les moyens de contrôle de la quantité de chaleur dégagée par la réaction produite dans le convertisseur catalytique comportent des moyens de mesure de la température des gaz d'échappement en aval dudit convertisseur et des moyens de comparaison de la température des gaz en aval du convertisseur avec une valeur seuil de détection d'un dysfonctionnement , etthe means for controlling the amount of heat generated by the reaction produced in the catalytic converter comprise means for measuring the temperature of the exhaust gases downstream of said converter and means for comparing the temperature of the gases downstream of the converter; with a threshold value for detecting a malfunction, and
- il comporte un calculateur assurant le contrôle de fonctionnement du moteur et le contrôle de fonctionnement du convertisseur catalytique, ce calculateur comprenant lesdits moyens de comparaison et des moyens de mémorisation dans lesquels sont stockés un ensemble de valeurs de seuil associées chacune à un des paramètres de fonctionnement du moteur et/ou du convertisseur catalytique et un ensemble de valeurs de température d'amorçage thermique du convertisseur catalytique en fonction du débit de gaz d'échappement dans ledit convertisseur, la valeur seuil fournie aux moyens de comparaison étant extraite des moyens de mémorisation en fonction des paramètres de fonctionnement mesurésit comprises a computer providing the control of the operation of the engine and the control of the operation of the catalytic converter, this computer comprising said comparison means and storage means in which are stored a set of threshold values each associated with one of the parameters of operation of the engine and / or the catalytic converter and a set of thermal initiation temperature values of the catalytic converter as a function of the flow of exhaust gas in said converter, the threshold value supplied to the comparison means being extracted from the storage means according to the measured operating parameters
L'invention concerne également un moteur à combustion interne pour véhicule automobile comprenant une ligne d'échappement équipée d'au moins un convertisseur catalytique et un dispositif de contrôle de l'état de fonctionnement dudit convertisseur catalytique tel que défini précédemmentThe invention also relates to an internal combustion engine for a motor vehicle comprising an exhaust line equipped with at least one catalytic converter and a device for controlling the operating state of said catalytic converter as defined above.
DESCRIPTION DÉTAILLÉE D'UN EXEMPLE DE RÉALISATION La description qui va suivre en regard des dessins annexés donnés à titre d'exemples non limitatifs, fera bien comprendre en quoi consiste l'invention et comment elle peut être réalisée Sur les dessins annexésDETAILED DESCRIPTION OF AN EXEMPLARY EMBODIMENT The following description with reference to the accompanying drawings given by way of non-limiting example, will make it clear what the invention consists of and how it can be achieved.
- la figure 1 est une vue schématique d'un premier mode de réalisation d'un moteur à combustion interne comprenant dans sa ligne d'échappement un convertisseur catalytique associé à un dispositif de contrôle selon l'invention, la figure 2 est une vue schématique d'un deuxième mode de réalisation d'un moteur à combustion interne comprenant dans sa ligne d'échappement un convertisseur catalytique associé à un dispositif de contrôle selon l'invention,FIG. 1 is a schematic view of a first embodiment of an internal combustion engine comprising in its exhaust line a catalytic converter associated with a control device according to the invention, FIG. 2 is a diagrammatic view. of a second embodiment of an internal combustion engine comprising in its exhaust line a catalytic converter associated with a control device according to the invention,
- la figure 3 est une vue schématique d'un troisième mode de réalisation d'un moteur à combustion interne comprenant dans sa ligne d'échappement un convertisseur catalytique associé à un dispositif de contrôle selon l'invention,FIG. 3 is a schematic view of a third embodiment of an internal combustion engine comprising in its exhaust line a catalytic converter associated with a control device according to the invention,
- la figure 4A est une vue schématique d'un premier mode de réalisation du système dédié d'alimentation du dispositif de contrôle selon l'invention, - la figure 4B est une vue schématique d'un deuxième mode de réalisation du système dédié d'alimentation du dispositif de contrôle selon l'invention,FIG. 4A is a schematic view of a first embodiment of the dedicated power supply system of the control device according to the invention; FIG. 4B is a schematic view of a second embodiment of the dedicated system of FIG. supply of the control device according to the invention,
- la figure 5 montre des courbes illustrant la variation de l'efficacité de conversion du monoxyde de carbone CO en fonction de la température en entrée du convertisseur, respectivement pour un convertisseur neuf et pour un convertisseur vieilli la figure 6 montre des courbes illustrant la variation de l'efficacité de conversion des hydrocarbures imbrûlés HC en fonction de la température en entrée du convertisseur, respectivement pour un convertisseur neuf et pour un convertisseur vieilli ,FIG. 5 shows curves illustrating the variation of the conversion efficiency of carbon monoxide CO as a function of the inlet temperature of the converter, respectively for a new converter and for an aged converter; FIG. 6 shows curves illustrating the variation; the conversion efficiency of unburned hydrocarbons HC as a function of the inlet temperature of the converter, respectively for a new converter and for an aged converter,
- la figure 7 montre des courbes illustrant le procédé mis en œuvre par le dispositif de contrôle selon l'invention pour contrôler l'état de fonctionnement d'un convertisseur catalytique d'un moteur à combustion interne , et - la figure 8 est un algorithme de fonctionnement du dispositif de contrôle selon l'inventionFIG. 7 shows curves illustrating the method implemented by the control device according to the invention for controlling the operating state of a catalytic converter of an internal combustion engine, and FIG. 8 is an algorithm. operation of the control device according to the invention
Préliminairement, on notera que d'une figure à l'autre, les éléments identiques ou similaires des différents modes de réalisation de l'invention seront dans la mesure du possible référencés par les mêmes signes de référence et ne seront pas décrits à chaque foisPreliminarily, it will be noted that from one figure to another, the identical or similar elements of the different embodiments of the invention will be referenced as far as possible by the same reference signs and will not be described each time.
Sur les figures 1 à 3, on a représente, de manière schématique, la structure générale de trois variantes d'un moteur 10 à combustion interne, ICI un moteur Diesel, d'un véhicule automobile Ce moteur 10 comporte une chambre de combustion 11 pourvue de cylindres Les cylindres de la chambre de combustion 11 sont alimentés en air de refroidissement par un refroidisseur 18 associé à un répartiteur d'admission (non représenté), lui-même alimenté par une conduite C pourvue en entrée d'un filtre à air 12 SUIVI d'un débitmètre 13 et d'un turbocompresseur 14 de suralimentation du moteur en airFIGS. 1 to 3 show schematically the general structure of three variants of an internal combustion engine 10, ICI a diesel engine, of a motor vehicle This engine 10 comprises a combustion chamber 11 provided with cylinders The cylinders of the combustion chamber 11 are supplied with cooling air by a cooler 18 associated with an intake distributor (not shown), itself fed by a pipe C provided with the input of an air filter 12 FOLLOWING a flowmeter 13 and a turbocharger 14 of supercharging the engine with air
Un collecteur d'échappement (non représenté) récupère les gaz d'échappement issus de la combustion et évacue ces derniers vers l'extérieur par une ligne d'échappement E via le turbocompresseur 14 Un circuit de recirculation R des gaz d'échappement récupère une partie des gaz d'échappement et les réinjecte dans le répartiteur d'admission de manière à limiter la quantité d'oxydes d'azote produit par la combustion tout en évitant la formation de fumée dans les gaz d'échappementAn exhaust manifold (not shown) recovers the exhaust gas from the combustion and discharges the latter to the outside by an exhaust line E via the turbocharger 14 A recirculation circuit R exhaust gas recovers a part of the exhaust gases and reinjects them into the intake manifold so as to limit the amount of nitrogen oxides produced by the combustion while avoiding the formation of smoke in the exhaust gas
Comme le montrent plus particulièrement les figures 1 à 3, le circuit de recirculation R comporte essentiellement une soupape 17 de réglage du flux de gaz d'échappement recirculés précédée d'un refroidisseur 16 alimenté par un by- pass 15As shown more particularly in FIGS. 1 to 3, the recirculation circuit R essentially comprises a valve 17 for regulating the recirculated exhaust gas flow preceded by a cooler 16 fed by a bypass 15
Fn ce qui concerne la ligne d'échappement E, celle-ci comprend deux convertisseurs catalytiques en série à savoir par exemple un catalyseur 30 SUIVI d'un filtre à particules ou d'un piège à Nox 31With regard to the exhaust line E, this comprises two catalytic converters in series, for example a catalyst SUIVI of a particulate filter or a Nox trap.
Bien entendu, on peut prévoir que le filtre à particules ou le piège à Nox précède le catalyseurOf course, it can be provided that the particulate filter or the Nox trap precedes the catalyst
Le catalyseur 30 assure essentiellement le post-traitement des gaz d'échappement par oxydation des molécules réductrices que sont le monoxyde de carbone (CO) et les hydrocarbures imbrûlés (HC) Le filtre à particules ou le piège à Nox 31 assure le post-traitement des particules et des NoxThe catalyst essentially ensures the post-treatment of the exhaust gases by oxidation of the reducing molecules, which are carbon monoxide (CO) and unburned hydrocarbons (HC). The particulate filter or the Nox trap 31 ensures the post-treatment particles and Nox
Le catalyseur 30 présente une structure classique à la portée de l'homme du métier et il ne sera pas ICI décrit dans le détailThe catalyst 30 has a conventional structure within the reach of those skilled in the art and it will not be described in detail
Pour l'essentiel, il présente une structure monolithique et est pourvu de canaux imprégnés d'une phase catalytique telle qu'un métal précieux, et présentant une grande surface de contact avec les gaz d'échappementFor the most part, it has a monolithic structure and is provided with channels impregnated with a catalytic phase such as a precious metal, and having a large contact surface with the exhaust gas
On notera également que le monolithe entrant dans la constitution du catalyseur 30 est ICI intégré au filtre à particules ou au piège à Nox 31 , afin de réaliser un couplage entre le post-traitement des gaz d'échappement par oxydation du monoxyde de carbone et des hydrocarbures imbrûlés (HC) au post- traitement des particules et des NoxIt will also be noted that the monolith forming part of the catalyst 30 is IC1 integrated in the particulate filter or the Nox trap 31, in order to achieve a coupling between the aftertreatment of the exhaust gases by oxidation of carbon monoxide and unburned hydrocarbons (HC) after particle and Nox post-treatment
Enfin, le moteur 10 est associé à un calculateur 27 embarqué assurant essentiellement le contrôle du fonctionnement du moteur 10, notamment le réglage de ses paramètres de fonctionnement, ainsi que le contrôle du fonctionnement d'au moins un des convertisseurs 30 31Finally, the engine 10 is associated with an on-board computer 27 essentially ensuring the control of the operation of the engine 10, in particular the adjustment of its operating parameters, as well as the control of the operation of at least one of the converters 30.
Pour procéder au contrôle du fonctionnement du moteur 10, le calculateur 27 est connecté aux principaux organes fonctionnels du moteur, ces connexions étant matérialisées par des lignes en traits pointillés Pour le contrôle du bon fonctionnement du convertisseur catalytique concerné 30,31 , le calculateur 27 comporte des moyens de mémorisation dans lesquels sont stockés un ensemble de données obtenues par apprentissage préalable correspondant notamment à des valeurs de seuil de détection de dysfonctionnement, ainsi que, le cas échéant, des valeurs de température en amont du convertisseur catalytique à contrôler en fonction de la température régnant en aval, et des moyens logiciels de contrôle de la quantité de chaleur dégagée par la réaction chimique engendrée par la post-injection au sein du convertisseur catalytique par comparaison avec des valeurs de seuilTo carry out the control of the operation of the engine 10, the computer 27 is connected to the main functional elements of the engine, these connections being represented by dashed lines. For the control of the proper operation of the catalytic converter concerned 30, 31, the computer 27 comprises storage means in which are stored a set of data obtained by prior learning corresponding in particular to malfunction detection threshold values, and, if appropriate, temperature values upstream of the catalytic converter to be controlled according to the temperature prevailing downstream, and software control means of the amount of heat released by the chemical reaction generated by the post-injection within the catalytic converter by comparison with threshold values
Plus particulièrement, le moteur 10 comporte en tant que dispositif de contrôle de l'état de fonctionnement d'un des convertisseurs 30,31 , des moyens de détermination 24, 25 de la température régnant en amont du convertisseur catalytique correspondant 30,31 , des moyens d'apport de carburant dans la ligne d'échappement E du moteur à l'instant auquel la température des gaz d'échappement en amont du convertisseur catalytique 30,31 correspond à la température d'amorçage d'un convertisseur ayant un fonctionnement normal et des moyens de contrôle 25,26 de la quantité de chaleur dégagée par la réaction produite dans le convertisseur catalytique 30,31 sous l'effet de cet apport de carburantMore particularly, the engine 10 comprises, as a device for controlling the operating state of one of the converters 30, 31, means 24 for determining the temperature prevailing upstream of the corresponding catalytic converter 30, 31, means for supplying fuel into the exhaust line E of the engine at the instant at which the temperature of the exhaust gas upstream of the catalytic converter 30,31 corresponds to the starting temperature of a converter having normal operation and control means 25,26 of the amount of heat generated by the reaction produced in the catalytic converter 30,31 under the effect of this fuel supply
Selon une caractéristique essentielle de ce dispositif de contrôle, lesdits moyens d'apport comprennent un système dédié 20 d'alimentation en carburant disposé en aval de la chambre de combustion 11, dans la ligne d'échappement E du moteur 10, en amont du convertisseur catalytique 30, 31 à contrôlerAccording to an essential characteristic of this control device, said delivery means comprise a dedicated fuel supply system disposed downstream of the combustion chamber 11, in the exhaust line E of the engine 10, upstream of the converter catalytic 30, 31 to be controlled
Selon l'exemple représenté sur la figure 1 , ce système dédié 20 d'alimentation est placé juste en amont du catalyseur 30 à contrôler Selon l'exemple représenté sur la figure 2, ce système dédié 20 d'alimentation est placé juste en amont du filtre à particules ou du piège à Nox 31 à contrôlerAccording to the example shown in FIG. 1, this dedicated feed system is placed just upstream of the catalyst to be controlled. According to the example shown in FIG. 2, this dedicated supply system is placed just upstream of the particulate filter or the Nox trap 31 to be controlled.
Selon l'exemple représenté sur la figure 3, ce système dédié 20 d'alimentation est placé en amont du turbocompresseur 14 afin de procéder au contrôle du catalyseur 30According to the example shown in FIG. 3, this dedicated supply system 20 is placed upstream of the turbocompressor 14 in order to carry out the control of the catalyst 30
Le système dédié 20 d'alimentation est connecté au calculateur 27 qui assure son pilotageThe dedicated power system 20 is connected to the computer 27 which ensures its control
Préférentiellement, il est prévu des moyens pour alimenter en carburant directement à partir du réservoir de carburant du véhicule automobile ledit système dédié 20 d'alimentation Ces moyens comprennent une pompe 28 qui amène le carburant par une conduite A jusqu'au système dédié 20 d alimentationPreferably, means are provided for supplying fuel directly from the fuel tank of the motor vehicle to said dedicated supply system. These means comprise a pump 28 which supplies the fuel via line A to the dedicated supply system 20.
Selon un mode de réalisation du dispositif de contrôle représenté plus particulièrement la figure 4A, le système dédié d'alimentation en carburant est un système d'injection 20 piloté directement par le calculateur 27According to one embodiment of the control device shown more particularly in FIG. 4A, the dedicated fuel supply system is an injection system controlled directly by the computer.
Selon un autre mode de réalisation du dispositif de contrôle représenté sur la figure 4B, le système dédié d'alimentation en carburant est un système de vaporisation 20 qui comoorte une chambre de vaporisation 22 immergée dans la conduite d'échappement E, cette chambre de vaporisation 22 étant raccordée à un système de chauffage de carburant 21 alimenté par ladite pompe 28 pilotée par le calculateur 27According to another embodiment of the control device shown in FIG. 4B, the dedicated fuel supply system is a vaporization system 20 which comoorte a vaporization chamber 22 immersed in the exhaust pipe E, this vaporization chamber 22 being connected to a fuel heating system 21 supplied by said pump 28 driven by the computer 27
Par ailleurs, selon l'exemple représenté sur les figures 1 à 3, les moyens de détermination de la température des gaz en amont du convertisseur catalytique 30,31 concerné comportent un moyen de mesure de ladite température des gaz Ici, il est prévu un capteur 24 de mesure de la température des gaz d'échappement en amont du convertisseur 30, un capteur 25 de mesure de la température des gaz d'échappement en aval du convertisseur 30 et en amont du convertisseur 31 , ainsi qu'un capteur 26 de mesure de la température des gaz d'échappement en aval du convertisseur 31 Les capteurs 24,25,26 sont raccordés au calculateur 27Moreover, according to the example shown in FIGS. 1 to 3, the means for determining the temperature of the gases upstream of the catalytic converter 30, 31 concerned have a means for measuring the temperature of the gases. Here, a sensor is provided. 24 for measuring the temperature of the exhaust gas upstream of the converter 30, a sensor 25 for measuring the temperature of the exhaust gas downstream of the converter 30 and upstream of the converter 31, and a sensor 26 for measuring the temperature of the exhaust gas downstream of the converter 31 The sensors 24,25,26 are connected to the computer 27
On notera que le capteur 24 de mesure de température est un élément optionnel, la température régnant en amont du convertisseur 30 pouvant être estimée, soit à partir d'un modèle mathématique et de paramètres de fonctionnement du moteur et/ou du convertisseur catalytique concerné, soit à partir de la température régnant en aval du convertisseur concerné hors phase de post-injectionIt will be noted that the temperature measurement sensor 24 is an optional element, the temperature prevailing upstream of the converter 30 can be estimated, either from a mathematical model and from operating parameters of the engine and / or the catalytic converter concerned, either to from the temperature prevailing downstream of the converter concerned outside the post-injection phase
Les mesures de température fournies par les capteurs 24, 25, 26 sont traitées par les moyens de calcul du calculateur 27 de manière à déterminer l'élévation de température d'amorçage du convertisseur 30, 31 contrôler pour détecter une baisse d'efficacité consécutive de conversion des hydrocarbures imbrûlés (HC) et du monoxyde de carbone (CO)The temperature measurements provided by the sensors 24, 25, 26 are processed by the calculation means of the calculator 27 so as to determine the rise temperature rise of the converter 30, 31 control to detect a decrease in subsequent efficiency of conversion of unburned hydrocarbons (HC) and carbon monoxide (CO)
En effet, en se référant à la figure 5, sur laquelle on a représenté la variation de l'efficacité de conversion du CO par le convertisseur catalytique 30,31 contrôler en fonction de la température en entrée du monolithe, pour un convertisseur neuf (courbe A) et pour un convertisseur vieilli (courbe B), on constate que le vieillissement d'un convertisseur s'accompagne d'une augmentation relativement importante de la température d amorçage du convertisseur, c'est-à-dire de la température à partir de laquelle l'efficacité de la conversion est au égale à 50%Indeed, with reference to FIG. 5, in which the variation of the conversion efficiency of the CO by the catalytic converter 30, 31 is shown to be controlled as a function of the inlet temperature of the monolith, for a new converter (curve A) and for an aged converter (curve B), it is found that the aging of a converter is accompanied by a relatively large increase in the starting temperature of the converter, that is to say the temperature from of which the efficiency of the conversion is equal to 50%
De même, en se référant à la figure 6, sur laquelle on a représenté l'évolution de l'efficacité de conversion des hydrocarbures imbrûlés HC en fonction de la température en entrée du monolithe, respectivement pour un convertisseur neuf (courbe C) et pour un convertisseur vieilli (courbe D), on constate également que le vieillissement du convertisseur s'accompagne d'une élévation relativement importante de la température d'amorçage du convertisseurSimilarly, with reference to FIG. 6, which shows the evolution of the conversion efficiency of unburned HC hydrocarbons as a function of the inlet temperature of the monolith, respectively for a new converter (curve C) and for an aged converter (curve D), it is also noted that the aging of the converter is accompanied by a relatively large rise in the starting temperature of the converter
Néanmoins, à haute température, la baisse de l'efficacité de conversion est négligeableNevertheless, at high temperatures, the decline in conversion efficiency is negligible
Ainsi pour contrôler le bon fonctionnement d'un convertisseur 30,31 , le calculateur procède à un contrôle de la température d'amorçage du convertisseur à contrôler et/ou à un contrôle, pour une température de fonctionnement correspondant à la température d'amorçage d'un convertisseur sain, de la quantité de chaleur dégagée par la réaction chimique d'oxydation mise en œuvre au sein du convertisseur Les moyens de contrôle de la quantité de chaleur dégagée par la réaction produite dans le convertisseur catalytique 30,31 comportent des moyens de mesure de la température des gaz d'échappement en aval dudit convertisseur, ICI les capteurs 25,26 et des moyens de comparaison prévus dans le calculateur 27 de la température des gaz en aval du convertisseur catalytique concerné avec une valeur seuil de détection d'un dysfonctionnementThus, in order to check the correct operation of a converter 30, 31, the computer carries out a control of the ignition temperature of the converter to be tested and / or a control, for an operating temperature corresponding to the ignition temperature of the converter. a converter, the amount of heat released by the chemical oxidation reaction implemented in the converter The means for controlling the amount of heat generated by the reaction produced in the catalytic converter 30,31 comprise means of measuring the temperature of the exhaust gas downstream of said converter, ICI the sensors 25,26 and comparison means provided in the computer 27 the gas temperature downstream of the catalytic converter concerned with a threshold value for detecting a malfunction
Par ailleurs, préférentiel lement, selon l'invention, il est prévu un système spécifique (non représenté) d'injection de carburant dans au moins un cylindre moteur pour amener la température des gaz d'échappement en amont du convertisseur catalytique à ladite température d'amorçage de ce dernier quelles que soient les conditions de roulage du véhicule automobile, ce système spécifique d'injection de carburant étant couplé audit système dédié 20 d'alimentation en carburant En référence plus particulièrement aux figures 7 et 8, nous allons maintenant décrire le procédé de contrôle du fonctionnement d'un des convertisseurs catalytiques 30,31 , par exemple le convertisseur 30 (sachant que ce procédé est identique pour l'autre convertisseur 31 )Furthermore, preferably, according to the invention, there is provided a specific system (not shown) for injecting fuel into at least one engine cylinder to bring the temperature of the exhaust gas upstream of the catalytic converter to said temperature of the engine. ignition of the latter whatever the driving conditions of the motor vehicle, this specific fuel injection system being coupled to said dedicated fuel supply system. Referring more particularly to FIGS. 7 and 8, we will now describe the method for controlling the operation of one of the catalytic converters 30, 31, for example the converter 30 (knowing that this method is identical for the other converter 31)
Lorsque le calculateur 27 reçoit une demande de diagnostique du convertisseur 30, il mesure par le capteur 24 la température des gaz d'échappement en amont du convertisseur 30 et vérifie que celle-ci est égale à la température d'amorçage du convertisseur 30 pour des conditions de roulage donnéesWhen the computer 27 receives a diagnostic request from the converter 30, it measures by the sensor 24 the temperature of the exhaust gas upstream of the converter 30 and verifies that it is equal to the ignition temperature of the converter 30 for driving conditions given
Si la température mesurée n'a pas atteint la température d'amorçage du convertisseur 30, le calculateur active le système spécifique d'injection de carburant dans la chambre de combustion du moteur de façon à l'amener à cette température d'amorçageIf the measured temperature has not reached the ignition temperature of the converter 30, the computer activates the specific fuel injection system in the combustion chamber of the engine so as to bring it to this priming temperature
Le calculateur 27 procède alors à une excitation du convertisseur catalytique 30 par injection ou vaporisation d'une quantité déterminée de carburant dans la ligne d'échappement E en amont du convertisseur 30 Pour cela le calculateur 27 commande l'injecteur 20 alimenté par ailleurs par la pompe 28The computer 27 then proceeds to an excitation of the catalytic converter 30 by injection or vaporization of a determined quantity of fuel in the exhaust line E upstream of the converter 30. For this, the computer 27 controls the injector 20, which is supplied by the pump 28
(voir figure 4A) ou la pompe 28 qui alimente le vaporisateur 22 via le système de réchauffement de carburant 21 (voir la figure 4B)(see Figure 4A) or the pump 28 which supplies the vaporizer 22 via the fuel heating system 21 (see Figure 4B)
Sur la figure 7 on a représenté l'évolution en fonction du temps de la température en amont d'un convertisseur neuf (courbe E), de la température en aval d'un convertisseur neuf (courbe F), de la température en amont d'un convertisseur vieilli (courbe G) et de la température en aval d'un convertisseur vieilli (courbe H) On remarquera à partir de ces courbes que la quantité de chaleur Q1 de chaleur dégagée par la réaction chimique d'oxydation au sein du convertisseur du fait de la post-injection, pour un convertisseur neuf, est très supérieure à la quantité de chaleur Q2 dégagée au cours de la réaction chimique d'oxydation au sein d'un convertisseur vieilliFIG. 7 shows the evolution as a function of time of the temperature upstream of a new converter (curve E), the temperature downstream of a new converter (curve F), the temperature upstream of an aged converter (curve G) and the temperature downstream of an aged converter (curve H) It will be noted from these curves that the amount of heat Q1 heat released by the oxidation chemical reaction in the converter because of the post-injection, for a new converter, is much greater than the amount of heat Q2 released during the oxidation chemical reaction within an aged converter
De même, on constate sur ces courbes que le temps d'amorçage d'un convertisseur neuf sollicité par une post-injection est bien plus court que le temps d'amorçage d'un convertisseur vieilli sollicité par une post-injectionLikewise, it can be seen from these curves that the priming time of a new converter solicited by a post-injection is much shorter than the starting time of an aged converter solicited by a post-injection
Ainsi après avoir excité le convertisseur catalytique 30, le calculateur 27 analyse le temps d'amorçage du convertisseur 30 ainsi que la quantité de chaleur dégagée par la réaction mise en œuvre au sein du convertisseur 30, par exemple par comparaison avec une valeur seuil en dessous de laquelle on considère que le convertisseur est défectueuxThus, after having excited the catalytic converter 30, the computer 27 analyzes the start-up time of the converter 30 as well as the quantity of heat released by the reaction implemented in the converter 30, for example by comparison with a threshold value below which one considers that the converter is defective
Le calculateur 27 procède à un calcul de la différence entre la température en aval du convertisseur et la température en amont du convertisseur, puis il procède à une comparaison de la différence ainsi calculée avec une valeur de seuil de détection d'un dysfonctionnement, traduisant le vieillissement du catalyseur Si un dysfonctionnement est détecté il est signalé au conducteur grâce à l'allumage d'un voyant sur le tableau de bord du véhicule automobile, sinon le calculateur 27 coupe le système dédié 20 de post-injection dans la ligne l'échappementThe calculator 27 proceeds with a calculation of the difference between the temperature downstream of the converter and the temperature upstream of the converter, then it carries out a comparison of the difference thus calculated with a threshold value of detection of a malfunction, reflecting the aging of the catalyst If a malfunction is detected, it is signaled to the driver by lighting a warning light on the dashboard of the motor vehicle, otherwise the computer 27 cuts off the dedicated post-injection system 20 in the exhaust line
La valeur de seuil utilisée pour contrôler le bon fonctionnement du convertisseur correspond à une quantité de chaleur dégagée par un convertisseur dont le vieillissement, et donc la capacité de conversion, est à la limite de l'admissibilitéThe threshold value used to check the correct functioning of the converter corresponds to a quantity of heat released by a converter whose aging, and thus the conversion capacity, is at the limit of eligibility.
De même le calculateur 27 calcule le temps de montée en température du convertisseur 30 teste et le compare à un temps de montée en température seuil d'un convertisseur à la limite de l'admissibilité Soit le temps de montée en température est inférieur au seuil donné et le convertisseur est considéré comme intègre soit il est supérieur à ce seuil et un dysfonctionnement du convertisseur est détecté Un tel dysfonctionnement est alors signale au conducteur grâce a l'allumage d'un voyant sur le tableau de bord du véhicule automobile Si aucun dysfonctionnement n'est détecté le calculateur 27 coupe le système dédié 20 de post-injection dans la ligne l'échappement Comme le montre l'algorithme de la figure 8, les tests de la quantité de chaleur et du temps d'amorçage peuvent être couplés par le calculateur 27 afin d'améliorer le diagnostic du convertisseur considéré.Similarly, the computer 27 calculates the temperature rise time of the tested converter 30 and compares it with a threshold temperature rise time of a converter at the limit of eligibility. The rise time is below the given threshold. and the converter is considered as integrates or it is higher than this threshold and a malfunction of the converter is detected Such a malfunction is then reported to the driver through the ignition of a light on the dashboard of the motor vehicle If no malfunction n is detected the computer 27 cuts the dedicated system 20 of post-injection in the line the exhaust As shown by the algorithm of FIG. 8, the tests of the amount of heat and of the initiation time can be coupled by the computer 27 in order to improve the diagnosis of the converter in question.
On notera à cet effet que, de préférence, le calculateur 27 comporte stockés en mémoire, un ensemble de valeurs seuil associées chacune à des paramètres spécifiques de fonctionnement du moteur.Note for this purpose that, preferably, the computer 27 includes stored in memory, a set of threshold values each associated with specific engine operating parameters.
Ainsi pour procédé au contrôle de l'état de fonctionnement d'un convertisseur, le calculateur 27 procède à une acquisition de paramètres de fonctionnement du moteur , tels que notamment, le régime de fonctionnement du moteur, la pression régnant dans le circuit d'admission d'air etc., qui sont fournis par des capteurs dont est équipé le moteur, de manière à déterminer les conditions de fonctionnement de ce dernier, puis extrait de la mémoire une ou des valeurs seuils correspondantes, de manière à adapter le niveau minimum de quantité de chaleur ou de temps d'amorçage admissible aux paramètres de fonctionnement du moteur.Thus, for the purpose of controlling the operating state of a converter, the computer 27 proceeds with an acquisition of engine operating parameters, such as, in particular, the operating speed of the engine, the pressure prevailing in the intake circuit. air, etc., which are provided by sensors of which the engine is equipped, so as to determine the operating conditions of the latter, and then extracts from the memory one or more corresponding threshold values, so as to adapt the minimum level of amount of heat or priming time permissible to the engine operating parameters.
On notera également que le calculateur 27 comporte également, stockée en mémoire, une cartographie dans laquelle sont mémorisés un ensemble de valeurs de débit de carburant et de phasage des post-injections en fonction des paramètres de fonctionnement du moteur, de manière à optimiser l'arrivée des hydrocarbures dans le convertisseur à tester alors qu'il s'amorce.It will also be noted that the computer 27 also comprises, stored in memory, a map in which are memorized a set of fuel flow and post-injection timing values as a function of the operating parameters of the engine, so as to optimize the arrival of hydrocarbons in the converter to be tested while it starts.
De même, le débit de carburant injecté est compris dans une plage bien déterminée afin de ne pas dégrader le convertisseur par un dégagement de chaleur trop important.Similarly, the injected fuel flow is within a specific range so as not to degrade the converter by excessive heat generation.
Pour la détermination de l'instant auquel la post-injection doit être réalisée, le calculateur acquiert la valeur de la température des gaz d'échappement en amont du convertisseur puis compare cette température à une température d'amorçage d'un convertisseur neuf. Dès que cette température est atteinte, il provoque la post-injection. À ce sujet, il convient de signaler que l'utilisation du système d'injection spécifique dans les cylindres du moteur pour augmenter la température des gaz en amont du convertisseur est optionnelle et le calculateur peut se contenter de surveiller cette température jusqu'à ce qu'elle atteigne la température d'amorçage visée.To determine the time at which the post-injection must be performed, the computer acquires the value of the temperature of the exhaust gas upstream of the converter and then compares this temperature to a starting temperature of a new converter. As soon as this temperature is reached, it causes the post-injection. In this regard, it should be noted that the use of the specific injection system in the engine cylinders to increase the temperature of the gas upstream of the converter is optional and the computer can simply monitor this temperature until it reaches the target priming temperature.
En outre, le capteur 24 de mesure de la température régnant en amont du convertisseur 30 est également optionnel. Dans le cas où ce capteur n'existerait pas, pour déterminer l'instant auquel la post-injection doit être effectuée pour procéder au contrôle de l'état de fonctionnement du convertisseur 30, le calculateur 27 peut comporter, stockées en mémoire, des valeurs de température en amont du convertisseur en fonction de la température régnant en aval et en fonction de conditions de fonctionnement du moteurIn addition, the sensor 24 for measuring the temperature prevailing upstream of the converter 30 is also optional. In the case where this sensor does not exist, to determine the instant at which the post-injection must be carried out in order to check the operating state of the converter 30, the computer 27 may comprise, stored in memory, values of temperature upstream of the converter as a function of the temperature prevailing downstream and as a function of engine operating conditions
Le calculateur 27 peut également comporter un modèle thermique des gaz d'échappement et procéder ainsi à un calcul de la température amont à partir des paramètres de fonctionnement du moteur et/ou du convertisseur La présente invention n'est nullement limitée aux modes de réalisation décrits et représentés mais l'homme du métier saura y apporter toute variante conforme à son esprit. The computer 27 may also include a thermal model of the exhaust gas and thus perform a calculation of the upstream temperature from the operating parameters of the engine and / or the converter. The present invention is not limited to the embodiments described. and represented but the person skilled in the art will be able to make any variant that fits his mind.

Claims

REVENDICATIONS
1 Dispositif de contrôle de l'état de fonctionnement d'un convertisseur catalytique (30,31 ) d'une ligne d'échappement (E) d'un moteur (10) à combustion interne, comprenant des moyens de détermination (24,25) de la température régnant en amont du convertisseur (30,31 ), des moyens d'apport de carburant dans la ligne d'échappement du moteur à instant auquel la température des gaz d'échappement en amont du convertisseur catalytique correspond à la température d'amorçage d'un convertisseur ayant un fonctionnement normal et des moyens de contrôle (25,26,27) de la quantité de chaleur dégagée par la réaction produite dans le convertisseur catalytique sous l'effet de cet apport de carburant, caractérisé en ce que lesdits moyens d'apport comprennent un système dédie (20) d'alimentation en carburant disposé dans la ligne d échappement du moteur en amont du convertisseur catalytique a contrôler1 Device for monitoring the operating state of a catalytic converter (30,31) of an exhaust line (E) of an internal combustion engine (10), comprising determining means (24,25 ) of the temperature prevailing upstream of the converter (30,31), fuel supply means in the exhaust line of the engine at which the temperature of the exhaust gas upstream of the catalytic converter corresponds to the temperature of d ignition of a converter having normal operation and control means (25,26,27) of the amount of heat generated by the reaction produced in the catalytic converter under the effect of this fuel supply, characterized in that said delivery means comprise a dedicated fuel supply system (20) disposed in the exhaust line of the engine upstream of the catalytic converter to be controlled
2 Dispositif de contrôle selon la revendication 1 , caractérisé en ce que le système dédié d'alimentation en carburant est un système d'injection (20)2 Control device according to claim 1, characterized in that the dedicated fuel supply system is an injection system (20)
3 Dispositif de contrôle selon la revendication 1 , caractérisé en ce que le système dédié d'alimentation en carburant est un système de vaporisation (20)3 Control device according to claim 1, characterized in that the dedicated fuel supply system is a vaporization system (20)
4 Dispositif de contrôle selon l'une des revendications 1 à 3, caractérisé en ce qu'il est prévu un système spécifique d'injection de carburant dans au moins un cylindre moteur pour amener la température des gaz d'échappement en amont du convertisseur catalytique à ladite température d'amorçage de ce dernier quelles que soient les conditions de roulage du véhicule automobile, ce système spécifique d'injection de carburant étant couplé audit système dédié d'alimentation en carburant 5 Dispositif de contrôle selon l'une des revendications 1 à 4, caractérisé en ce qu'il est prévu des moyens (28) pour alimenter en carburant directement à partir du réservoir de carburant du véhicule automobile ledit système dédié d'alimentation4 Control device according to one of claims 1 to 3, characterized in that there is provided a specific fuel injection system in at least one engine cylinder to bring the temperature of the exhaust gas upstream of the catalytic converter at said ignition temperature of the latter whatever the driving conditions of the motor vehicle, this specific fuel injection system being coupled to said dedicated fuel supply system 5 Control device according to one of claims 1 to 4, characterized in that there is provided means (28) for supplying fuel directly from the fuel tank of the motor vehicle said dedicated power system
6 Dispositif de contrôle selon l'une des revendications 1 à 5, caractérisé en ce que les moyens de détermination de la température des gaz en amont du convertisseur catalytique comportent un moyen de mesure (24,25) de ladite température des gaz 7. Dispositif de contrôle selon l'une des revendications 1 à 5, caractérisé en ce que les moyens de détermination de la température des gaz en amont du convertisseur catalytique comportent des moyens de mesure de paramètres de fonctionnement du moteur et/ou du convertisseur catalytique et un modèle thermique des gaz d'échappement adapté à déterminer la température des gaz en amont du convertisseur catalytique en fonction de paramètres de fonctionnement du moteur et/ou du convertisseur.6 Control device according to one of claims 1 to 5, characterized in that the means for determining the temperature of the gas upstream of the catalytic converter comprise a means (24,25) for measuring said gas temperature 7. Control device according to one of claims 1 to 5, characterized in that the means for determining the temperature of the gas upstream of the catalytic converter comprise means for measuring operating parameters of the engine and / or the catalytic converter. and a thermal model of the exhaust gas adapted to determine the temperature of the gases upstream of the catalytic converter according to operating parameters of the engine and / or the converter.
8. Dispositif de contrôle selon l'une des revendications 1 à 3, caractérisé en ce que les moyens de contrôle de la quantité de chaleur dégagée par la réaction produite dans le convertisseur catalytique comportent des moyens de mesure (25,26) de la température des gaz d'échappement en aval dudit convertisseur et des moyens de comparaison de la température des gaz en aval du convertisseur catalytique avec une valeur seuil de détection d'un dysfonctionnement. 9. Dispositif de contrôle selon la revendication 8, caractérisé en ce qu'il comporte un calculateur (27) assurant le contrôle de fonctionnement du moteur et le contrôle de fonctionnement du convertisseur, ce calculateur comprenant lesdits moyens de comparaison et des moyens de mémorisation dans lesquels sont stockées un ensemble de valeurs de seuil associées chacune à un des paramètres de fonctionnement du moteur et/ou du convertisseur catalytique et un ensemble de valeurs de température d'amorçage thermique du convertisseur catalytique en fonction du débit de gaz d'échappement dans ledit convertisseur, la valeur seuil fournie aux moyens de comparaison étant extraite des moyens de mémorisation en fonction des paramètres de fonctionnement mesurés. 10. Moteur (10) à combustion interne pour véhicule automobile comprenant une ligne d'échappement (E) équipée d'au moins un convertisseur catalytique (30,31 ) et un dispositif de contrôle de l'état de fonctionnement dudit convertisseur catalytique selon l'une quelconque des revendications 1 à 9. 8. Control device according to one of claims 1 to 3, characterized in that the means for controlling the amount of heat generated by the reaction produced in the catalytic converter comprise means (25,26) for measuring the temperature. exhaust gas downstream of said converter and means for comparing the temperature of the gas downstream of the catalytic converter with a threshold value for detecting a malfunction. 9. Control device according to claim 8, characterized in that it comprises a computer (27) providing the operation control of the engine and the operation control of the converter, the computer comprising said comparison means and memory means in which are stored a set of threshold values each associated with one of the operating parameters of the engine and / or the catalytic converter and a set of thermal initiation temperature values of the catalytic converter as a function of the flow of exhaust gas in said converter, the threshold value supplied to the comparison means being extracted from the storage means as a function of the measured operating parameters. 10. Internal combustion engine (10) for a motor vehicle comprising an exhaust line (E) equipped with at least one catalytic converter (30,31) and a device for controlling the operating state of said catalytic converter according to the invention. any one of claims 1 to 9.
EP05816061A 2004-11-02 2005-10-25 Device for controlling the operating state of a catalytic converter of an exhaust line pertaining to an internal combustion engine, and engine comprising one such device Withdrawn EP1809878A1 (en)

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FR0411640A FR2877392A1 (en) 2004-11-02 2004-11-02 DEVICE FOR CONTROLLING THE OPERATING STATE OF A CATALYTIC CONVERTER OF AN EXHAUST LINE OF AN INTERNAL COMBUSTION ENGINE AND AN ENGINE COMPRISING SUCH A DEVICE
PCT/FR2005/050899 WO2006048572A1 (en) 2004-11-02 2005-10-25 Device for controlling the operating state of a catalytic converter of an exhaust line pertaining to an internal combustion engine, and engine comprising one such device

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