WO2020201648A1 - Method for diagnosing the presence of frost in the tapping of a differential pressure sensor - Google Patents
Method for diagnosing the presence of frost in the tapping of a differential pressure sensor Download PDFInfo
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- WO2020201648A1 WO2020201648A1 PCT/FR2020/050478 FR2020050478W WO2020201648A1 WO 2020201648 A1 WO2020201648 A1 WO 2020201648A1 FR 2020050478 W FR2020050478 W FR 2020050478W WO 2020201648 A1 WO2020201648 A1 WO 2020201648A1
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- backpressure
- particulate filter
- dpdv
- volume flow
- sensor
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
- F01N3/02—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust
- F01N3/021—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters
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- 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
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- 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
- F01N13/008—Mounting or arrangement of exhaust sensors in or on exhaust apparatus
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M15/00—Testing of engines
- G01M15/04—Testing internal-combustion engines
- G01M15/10—Testing internal-combustion engines by monitoring exhaust gases or combustion flame
- G01M15/102—Testing internal-combustion engines by monitoring exhaust gases or combustion flame by monitoring exhaust gases
- G01M15/106—Testing internal-combustion engines by monitoring exhaust gases or combustion flame by monitoring exhaust gases using pressure sensors
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- 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
- F01N2560/08—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics the means being a pressure sensor
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- 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
- 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
- F01N2900/00—Details of electrical control or of the monitoring of the exhaust gas treating apparatus
- F01N2900/04—Methods of control or diagnosing
- F01N2900/0416—Methods of control or diagnosing using the state of a sensor, e.g. of an exhaust gas sensor
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- 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
- F01N2900/00—Details of electrical control or of the monitoring of the exhaust gas treating apparatus
- F01N2900/04—Methods of control or diagnosing
- F01N2900/0422—Methods of control or diagnosing measuring the elapsed time
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- 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
- F01N2900/00—Details of electrical control or of the monitoring of the exhaust gas treating apparatus
- F01N2900/06—Parameters used for exhaust control or diagnosing
- F01N2900/14—Parameters used for exhaust control or diagnosing said parameters being related to the exhaust gas
- F01N2900/1406—Exhaust gas pressure
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/10—Internal combustion engine [ICE] based vehicles
- Y02T10/12—Improving ICE efficiencies
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/10—Internal combustion engine [ICE] based vehicles
- Y02T10/40—Engine management systems
Definitions
- the present invention is in the field of the pollution control of the exhaust gases of a heat engine. More specifically, the invention relates to a method for diagnosing the presence of gel in a tap of a differential pressure sensor at the terminals of a particulate filter.
- the invention finds a particularly advantageous, but not exclusive, application with internal combustion compression or spark ignition engines equipped with a particulate filter associated with a differential pressure sensor.
- solid or liquid particles consisting essentially of carbon-based soot and / or oil droplets may be emitted. These particles typically have a size of between a few nanometers and one micrometer.
- particle filters usually made of a mineral matrix, of ceramic type, of honeycomb structure, defining channels arranged substantially parallel to the general direction of flow of the exhaust gases in the filter. , and alternately closed on the side of the gas inlet face of the filter and on the side of the gas outlet face of the filter, as described in document EP2426326.
- the exhaust line is also provided with a differential pressure measurement sensor, said back pressure sensor, to measure the pressure difference between an upstream connection and a downstream connection of the particulate filter from which it is possible to deduce a mass of accumulated soot.
- a map is used which establishes a correlation between the measurement of the pressure difference and the mass of soot in the particulate filter.
- the back pressure sensor is thus used to carry out the necessary diagnostics of the state of the particulate filter and required by regulations (called "OBD” for "On Board Diagnostic” in English) as well as safety diagnostics. Its information is therefore essential to guarantee the proper functioning of the heat engine. However, when the outside conditions are cold, the presence of frost in the sensor connections can falsify the information acquired by the sensor and therefore the interpretation of it by the engine ECU.
- the invention aims to effectively remedy this drawback by providing a method for diagnosing the presence of gel in a tap of a differential pressure sensor, called back pressure sensor, connected upstream and downstream of a filter. particles intended to filter the exhaust gases of a heat engine, said method comprising:
- the invention thus makes it possible to reduce the false detections of the diagnostics of the state of the particulate filter which are based on the backpressure information and which would be produced because of the formation of gel in the nozzles of the sensor caused by cold outdoor conditions. This translates into economic gain for the driver and the manufacturer if the vehicle is still within the warranty period by reducing the number of after-sales service interventions due to false detections.
- the analysis step comprises:
- the reference value is calculated at the start of the time interval.
- a method for calculating the gradient of the backpressure of the particulate filter as a function of the volume flow rate of the exhaust gas upstream of the particulate filter consists in taking a sample of points of size N, each point being a pair of measurements comprising a measurement of back pressure returned by the sensor and a measurement of the volume flow rate upstream of the particulate filter, and in calculating a linear regression on these points.
- said method comprises the step of retaining only the backpressure and volume flow measurements which have been obtained under conditions of stable operation of the heat engine.
- the back pressure and volume flow measurements are considered to have been obtained under conditions of stable operation of the heat engine when a derivative of the volume flow rate of the exhaust gases upstream of the filter. particles is less than a maximum bound.
- the time interval is between 2 and 3 minutes.
- said method is implemented only if an outside temperature is less than 0 ° C.
- the subject of the invention is also a computer comprising a memory storing software instructions for implementing the method as defined above.
- FIG. 1 is a schematic representation of an exhaust line of a heat engine comprising a particulate filter and a computer allowing the implementation of the method according to the invention
- FIG. 2 is a diagram of the different steps of the method according to the invention for detecting the presence of gel in a tap of a back pressure sensor;
- FIG. 3 is a graphic representation of differential pressure measurements returned by the backpressure sensor as a function of measurements of the exhaust gas flow rate of the heat engine;
- FIG. 4 is a representation of temporal diagrams of the evolution of signals illustrating a detection of a gel plug in a tap of a backpressure sensor during an implementation of the method according to the invention.
- FIG. 1 shows a heat engine 10 in particular intended to equip a motor vehicle.
- the heat engine 10 may be compression or controlled ignition.
- the heat engine 10 is connected to an exhaust line 11 for the evacuation of the burnt gases produced by the operation of the heat engine 10.
- the exhaust line 1 1 comprises a pollution control member 12 of gaseous pollutant, for example an oxidation catalyst or a three-way catalyst.
- the three-way catalyst 12 makes it possible in particular to reduce the oxides of nitrogen to nitrogen and to carbon dioxide, to oxidize the carbon monoxides to carbon dioxide, and the unburnt hydrocarbons to carbon dioxide and to water.
- the exhaust line 1 1 further comprises a particulate filter 13 for filtering soot particles in the exhaust gases of the heat engine 10.
- the particulate filter 13 is suitable for filtering soot particles from fuel combustion.
- the exhaust gases pass through the material making up the particulate filter 13.
- each of these channels comprises a plugged end, so that the exhaust gases flowing in the particle filter 13 pass from channel to channel, passing through the walls of the various channels of the particle filter 13 to exit the particle filter 13.
- the particle filter 13 may be based on 'a porous ceramic matrix, for example of cordierite, mullite, aluminum titanate or silicon carbide. If necessary, the depollution unit 12 and the particulate filter 13 may be located inside the same envelope 15.
- the exhaust line 1 1 is also provided with a sensor 16, said back pressure sensor, for the differential pressure measurement between the upstream and downstream of the particulate filter 13 from which it is possible to deduce a mass of accumulated soot.
- the sensor 16 is connected upstream and downstream of the particulate filter 13 respectively by means of an upstream connection 16.1 and a downstream connection 16.2.
- a map makes it possible to establish a correlation between the differential pressure measurement and the mass of soot in the particulate filter 13.
- a computer 17, for example the engine computer or a dedicated computer comprises a memory storing software instructions for the implementation of the method according to the invention for diagnosing the presence of frost in a tap 16.1, 16.2 of the sensor of back pressure 16.
- the computer 17 receives as input a measurement of the back pressure dP across the filter 13 returned by the sensor 16, an estimate of the volume flow Qvol of the exhaust gases upstream of the particulate filter 13, as well than an outside temperature because the diagnostic is preferably activated only for temperatures below 0 ° Q to exclude false detection which would be due to fouling other than freezing.
- Calculator 17 is able to generate at output a fault signal F_def in state 1 in the event of detection of the presence of frost in a tap 16.1, 16.2.
- the computer 17 calculates a gradient dPdV of the back pressure dP returned by the back pressure sensor 16 as a function of the volume flow Qvol of the exhaust gases upstream of the particulate filter 13 expressed in KPa / (m 3 / s).
- backpressure dP and volume flow Qvol can be approximated by a polynomial of order 2 or quadratic, but there is a range PJin of volume flow in which the relationship can be considered as linear, with acceptable errors, as shown in Figure 3.
- the dPdV gradient calculation method consists in taking a sample of points of size N, calibratable for example between 800 and 1000. Each point is a couple of measurements: a measurement of back pressure dP expressed in mbar and a flow measurement volume Qvol upstream of the particle filter 13 expressed in m 3 / s. A linear regression is then calculated on these points, in particular by the least squares method.
- all the measurements of back pressure dP and volume flow rate Qvol are not used for the calculation of the gradient dPdV.
- a criterion is applied in order to take into account only the measurements which are obtained under stabilized operating conditions of the heat engine.
- stabilized operating conditions is meant the operating conditions of the thermal engine for which the flow rate of the exhaust gases Qvol does not vary abruptly, in other words, in the absence of sudden acceleration or braking.
- This criterion is verified by calculating the derivative of the volume flow Qvol of the exhaust gases upstream of the filter 13 which indicates the rate of change of this flow as a function of time, and by ensuring that this value is less than a maximum limit, for example of the order of 0.05 m 3 / s 2 .
- a maximum limit for example of the order of 0.05 m 3 / s 2 .
- By “of the order of” is meant a variation of plus or minus 10% around this value. Thanks to this criterion, it is possible to improve the precision of the calculation of the dPdV gradient.
- the stabilized points which are retained for the calculation are represented by crosses; while the transient points which are not retained for the calculation are represented by circles.
- a time interval I is defined in which the behavior of the calculation of the gradient dPdV is observed.
- This time interval I also referred to as the observation window, is provided sufficiently short to exclude a false detection which would be due to a fouling other than by freezing.
- fouling other than by freezing for example by soot or ash, causes a slow change in the backpressure gradient.
- a faster evolution of this backpressure gradient during this time interval I is indicative of the appearance of gel in the nozzle.
- This time interval I is for example between two and three minutes.
- a reference value of the gradient dPdV_ref is stored at the start of each interval I and maintained throughout the interval I.
- the computer 17 also calculates current (or instantaneous) gradient values dPdVJnst. The computer 17 therefore performs two different calculations, namely the calculation of the current gradient dPdVJnst and the reference gradient dPdV_ref frozen at the start of the time interval I.
- the ratio R_dPdV is compared with a minimum threshold Smin and a maximum threshold Smax.
- the minimum threshold Smin is for example equal to 0.5 while the maximum threshold Smax is for example equal to 2.
- the result of this comparison determines the result of the diagnosis. Indeed, in the case where the ratio is between the minimum threshold Smin and the maximum threshold Smax, then we deduce that there is no presence of gel in the nozzles 16.1, 16.2 of the backpressure sensor 16. If the ratio is not between the minimum threshold Smin and the maximum threshold Smax, then we deduce that there is has a presence of gel in a nozzle 16.1, 16.2 of the backpressure sensor 16.
- Figure 4 shows a temporal evolution of the signals obtained during an implementation of the method according to the invention for detecting the presence of gel in a tap 16.1, 16.2 of the backpressure sensor 16.
- the points P indicate the instants at the start of time interval I at which the reference gradient dPdV_ref is calculated.
- the ratio R_dPdV is between the minimum threshold Smin and the maximum threshold Smax.
- a strong change in the R_dPdV ratio is observed, which exceeds the maximum authorized Smax threshold. This indicates an anomaly in the measurement of the back pressure of the particulate filter 13, probably caused by the presence of a gel plug in a nozzle 16.1, 16.2.
- the fault signal F_def then changes to state 1.
- the dPdVJnst parameter is not supposed to change rapidly under normal operating conditions, that is to say without disturbing the back pressure measurement.
- the dPdVJnst parameter changes with the storage of particles in the filter 13 in a slow manner due to the relatively low speed of production of particles by the heat engine 10.
- the calculated ratio is the inverse ratio of that previously indicated.
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- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Analytical Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Combined Controls Of Internal Combustion Engines (AREA)
- Exhaust Gas After Treatment (AREA)
- Measuring Fluid Pressure (AREA)
Abstract
The invention relates to a method for diagnosing the presence of frost in the tapping of a differential pressure sensor, referred to as a backpressure sensor, comprising: - a step of defining a time interval (I), - a step of calculating a reference value (dPdV_ref) of a gradient of a backpressure of the particulate filter returned by the backpressure sensor depending on a volume flow rate of the exhaust gases upstream of the particulate filter, and - a step of analysing an evolution, over the time interval (I), of an instantaneous value (dPdVJnst) of the gradient of the backpressure of the particulate filter returned by the backpressure sensor depending on the volume flow rate of the exhaust gases upstream of the particulate filter compared to the reference value (dPdV_ref) previously calculated to deduce the presence or absence of frost in the tapping of the backpressure sensor.
Description
DESCRIPTION DESCRIPTION
Titre de l'invention : PROCEDE DE DIAGNOSTIC DE PRESENCE DE GEL DANS UN PIQUAGE D'UN CAPTEUR DE PRESSION DIFFERENTIELLE Title of the invention: PROCESS FOR DIAGNOSING THE PRESENCE OF GEL IN A PITCH OF A DIFFERENTIAL PRESSURE SENSOR
[0001 ] La présente invention revendique la priorité de la demande française 1903564 déposée le 3 avril 2019 dont le contenu (texte, dessins et revendications) est ici incorporé par reference. The present invention claims the priority of French application 1903564 filed April 3, 2019, the content of which (text, drawings and claims) is incorporated here by reference.
[0002] La présente invention se situe dans le domaine de la dépollution des gaz d'échappement d'un moteur thermique. Plus précisément, l’invention porte sur un procédé de diagnostic de présence de gel dans un piquage d’un capteur de pression différentielle aux bornes d’un filtre à particules. L’invention trouve une application particulièrement avantageuse, mais non exclusive, avec les moteurs à combustion interne à compression ou à allumage commandé dotés d’un filtre à particules associé à un capteur de pression différentielle. The present invention is in the field of the pollution control of the exhaust gases of a heat engine. More specifically, the invention relates to a method for diagnosing the presence of gel in a tap of a differential pressure sensor at the terminals of a particulate filter. The invention finds a particularly advantageous, but not exclusive, application with internal combustion compression or spark ignition engines equipped with a particulate filter associated with a differential pressure sensor.
[0003] Lors de la combustion d'un mélange d'air et de carburant dans un moteur thermique, des particules solides ou liquides constituées essentiellement de suies à base de carbone et/ou de gouttelettes d'huile peuvent être émises. Ces particules ont typiquement une taille comprise entre quelques nanomètres et un micromètre. Pour les piéger, on peut avantageusement prévoir des filtres à particules, usuellement constitués d'une matrice minérale, de type céramique, de structure alvéolaire, définissant des canaux disposés sensiblement parallèlement à la direction générale d'écoulement des gaz d'échappement dans le filtre, et alternativement obturés du côté de la face d'entrée des gaz du filtre et du côté de la face de sortie des gaz du filtre, comme cela est décrit dans le document EP2426326. [0003] During the combustion of a mixture of air and fuel in a heat engine, solid or liquid particles consisting essentially of carbon-based soot and / or oil droplets may be emitted. These particles typically have a size of between a few nanometers and one micrometer. To trap them, one can advantageously provide particle filters, usually made of a mineral matrix, of ceramic type, of honeycomb structure, defining channels arranged substantially parallel to the general direction of flow of the exhaust gases in the filter. , and alternately closed on the side of the gas inlet face of the filter and on the side of the gas outlet face of the filter, as described in document EP2426326.
[0004] La ligne d'échappement est également munie d'un capteur de mesure de pression différentielle, dit capteur de contrepression, pour mesurer la différence de pression entre un piquage amont et un piquage aval du filtre à particules à partir de laquelle il est possible de déduire une masse de suies accumulées. A cet effet, on utilise une cartographie établissant une corrélation entre la mesure de différence de pression et la masse de suies dans le filtre à particules.
[0005] Le capteur de contrepression sert ainsi à réaliser les diagnostics nécessaires de l’état du filtre à particules et demandés par les réglementations (dites "OBD" pour "On Board Diagnostic" en anglais) ainsi que les diagnostics de sécurité. Son information est donc indispensable pour garantir le bon fonctionnement du moteur thermique. Toutefois, lorsque les conditions extérieures sont froides, la présence de gel dans les piquages du capteur peut fausser l’information acquise par le capteur et donc l’interprétation de celle-ci par le calculateur moteur. The exhaust line is also provided with a differential pressure measurement sensor, said back pressure sensor, to measure the pressure difference between an upstream connection and a downstream connection of the particulate filter from which it is possible to deduce a mass of accumulated soot. To this end, a map is used which establishes a correlation between the measurement of the pressure difference and the mass of soot in the particulate filter. [0005] The back pressure sensor is thus used to carry out the necessary diagnostics of the state of the particulate filter and required by regulations (called "OBD" for "On Board Diagnostic" in English) as well as safety diagnostics. Its information is therefore essential to guarantee the proper functioning of the heat engine. However, when the outside conditions are cold, the presence of frost in the sensor connections can falsify the information acquired by the sensor and therefore the interpretation of it by the engine ECU.
[0006] L'invention vise à remédier efficacement à cet inconvénient en proposant un procédé de diagnostic de présence de gel dans un piquage d'un capteur de pression différentielle, dit capteur de contrepression, connecté en amont et en aval d'un filtre à particules destiné à filtrer des gaz d’échappement d'un moteur thermique, ledit procédé comportant: The invention aims to effectively remedy this drawback by providing a method for diagnosing the presence of gel in a tap of a differential pressure sensor, called back pressure sensor, connected upstream and downstream of a filter. particles intended to filter the exhaust gases of a heat engine, said method comprising:
- une étape de définition d'un intervalle de temps, - a step of defining a time interval,
- une étape de calcul d'une valeur de référence d'un gradient d'une contrepression du filtre à particules retournée par le capteur de contrepression en fonction d'un débit volumique des gaz d'échappement en amont du filtre à particules, et a step of calculating a reference value of a gradient of a backpressure of the particulate filter returned by the backpressure sensor as a function of a volume flow rate of the exhaust gases upstream of the particulate filter, and
- une étape d'analyse d'une évolution, sur l'intervalle de temps, d'une valeur instantanée du gradient de la contrepression du filtre à particules retournée par le capteur de contrepression en fonction du débit volumique des gaz d'échappement en amont du filtre à particules par rapport à la valeur de référence précédemment calculée pour en déduire la présence ou non de gel dans un piquage du capteur de contrepression. a step of analyzing an evolution, over the time interval, of an instantaneous value of the gradient of the backpressure of the particle filter returned by the backpressure sensor as a function of the volume flow rate of the upstream exhaust gases of the particulate filter with respect to the previously calculated reference value in order to deduce therefrom the presence or absence of gel in a tap of the backpressure sensor.
[0007] L’invention permet ainsi de diminuer les fausses détections des diagnostics de l’état du filtre à particules qui se basent sur l’information de contrepression et qui seraient produites à cause de la formation de gel dans les piquages du capteur provoquée par des conditions extérieures froides. Cela se traduit par un gain économique pour le conducteur et le constructeur si le véhicule se trouve encore dans la période de garantie en réduisant le nombre d’interventions en service après-vente dues aux fausses détections. [0007] The invention thus makes it possible to reduce the false detections of the diagnostics of the state of the particulate filter which are based on the backpressure information and which would be produced because of the formation of gel in the nozzles of the sensor caused by cold outdoor conditions. This translates into economic gain for the driver and the manufacturer if the vehicle is still within the warranty period by reducing the number of after-sales service interventions due to false detections.
[0008] Selon une mise en oeuvre, l'étape d'analyse comporte: [0008] According to one implementation, the analysis step comprises:
- une étape de calcul d'un ratio entre la valeur instantanée du gradient de la contrepression et la valeur de référence précédemment calculée,
- une étape de comparaison du ratio calculé avec un seuil maximum et un seuil minimum, et - a step of calculating a ratio between the instantaneous value of the gradient of the backpressure and the previously calculated reference value, - a step of comparing the calculated ratio with a maximum threshold and a minimum threshold, and
- une étape de détermination de la présence de gel ou non dans un piquage en fonction d'un résultat de la comparaison précédemment réalisée. a step of determining the presence of gel or not in a stitching as a function of a result of the comparison carried out previously.
[0009] Selon une mise en oeuvre, la valeur de référence est calculée au début de l'intervalle de temps. [0009] According to one implementation, the reference value is calculated at the start of the time interval.
[0010] Selon une mise en oeuvre, une méthode de calcul du gradient de la contrepression du filtre à particules en fonction du débit volumique des gaz d'échappement en amont du filtre à particules consiste à prendre un échantillon de points de taille N, chaque point étant un couple de mesures comprenant une mesure de contrepression retournée par le capteur et une mesure de débit volumique en amont du filtre à particules, et à calculer une régression linéaire sur ces points. [0010] According to one implementation, a method for calculating the gradient of the backpressure of the particulate filter as a function of the volume flow rate of the exhaust gas upstream of the particulate filter consists in taking a sample of points of size N, each point being a pair of measurements comprising a measurement of back pressure returned by the sensor and a measurement of the volume flow rate upstream of the particulate filter, and in calculating a linear regression on these points.
[001 1 ] Selon une mise en oeuvre, ledit procédé comporte l’étape de retenir uniquement les mesures de contrepression et de débit volumique qui ont été obtenues en conditions de stabilité de fonctionnement du moteur thermique. [001 1] According to one implementation, said method comprises the step of retaining only the backpressure and volume flow measurements which have been obtained under conditions of stable operation of the heat engine.
[0012] Selon une mise en oeuvre, les mesures de contrepression et de débit volumique sont considérées comme ayant été obtenues dans des conditions de stabilité de fonctionnement du moteur thermique lorsqu’une dérivée du débit volumique des gaz d’échappement en amont du filtre à particules est inférieure à une borne maximum. According to one implementation, the back pressure and volume flow measurements are considered to have been obtained under conditions of stable operation of the heat engine when a derivative of the volume flow rate of the exhaust gases upstream of the filter. particles is less than a maximum bound.
[0013] Selon une mise en oeuvre, l’intervalle de temps est compris entre 2 et 3 minutes. [0013] According to one implementation, the time interval is between 2 and 3 minutes.
[0014] Selon une mise en oeuvre, ledit procédé est mis en oeuvre uniquement si une température extérieure est inférieure à 0° C. [0014] According to one implementation, said method is implemented only if an outside temperature is less than 0 ° C.
[0015] Selon une mise en oeuvre, suite à un défaut lié à une détection de la présence de gel dans un piquage, ledit procédé de diagnostic sera réhabilité lorsque le ratio repasse à une valeur située entre le seuil minimum et le seuil maximum.
[0016] L'invention a également pour objet un calculateur comportant une mémoire stockant des instructions logicielles pour la mise en oeuvre du procédé tel que précédemment défini. [0015] According to one implementation, following a fault linked to detection of the presence of gel in a stitching, said diagnostic process will be rehabilitated when the ratio returns to a value situated between the minimum threshold and the maximum threshold. [0016] The subject of the invention is also a computer comprising a memory storing software instructions for implementing the method as defined above.
[0017] L’invention sera mieux comprise à la lecture de la description qui suit et à l’examen des figures qui l’accompagnent. Ces figures ne sont données qu’à titre illustratif mais nullement limitatif de l’invention. [0017] The invention will be better understood from reading the description which follows and from examining the accompanying figures. These figures are given only by way of illustration but in no way limit the invention.
[0018] [Fig. 1 ] La figure 1 est une représentation schématique d'une ligne d'échappement d'un moteur thermique comportant un filtre à particules et un calculateur permettant la mise en oeuvre du procédé selon l'invention; [0018] [Fig. 1] FIG. 1 is a schematic representation of an exhaust line of a heat engine comprising a particulate filter and a computer allowing the implementation of the method according to the invention;
[0019] [Fig. 2] La figure 2 est un diagramme des différentes étapes du procédé selon l'invention de détection de la présence de gel dans un piquage d'un capteur de contrepression; [0019] [Fig. 2] FIG. 2 is a diagram of the different steps of the method according to the invention for detecting the presence of gel in a tap of a back pressure sensor;
[0020] [Fig. 3] La figure 3 est une représentation graphique de mesures de pression différentielle retournée par le capteur de contrepression en fonction de mesures de débit des gaz d'échappement du moteur thermique; [0020] [Fig. 3] FIG. 3 is a graphic representation of differential pressure measurements returned by the backpressure sensor as a function of measurements of the exhaust gas flow rate of the heat engine;
[0021 ] [Fig. 4] La figure 4 est une représentation de digrammes temporels de l'évolution de signaux illustrant une détection d'un bouchon de gel dans un piquage d'un capteur de contrepression lors d'une mise en oeuvre du procédé selon l'invention. [0021] [Fig. 4] FIG. 4 is a representation of temporal diagrams of the evolution of signals illustrating a detection of a gel plug in a tap of a backpressure sensor during an implementation of the method according to the invention.
[0022] La figure 1 représente un moteur thermique 10 notamment destiné à équiper un véhicule automobile. Le moteur thermique 10 pourra être à compression ou à allumage commandé. Le moteur thermique 10 est relié à une ligne d'échappement 11 pour l’évacuation des gaz brûlés produits par le fonctionnement du moteur thermique 10. FIG. 1 shows a heat engine 10 in particular intended to equip a motor vehicle. The heat engine 10 may be compression or controlled ignition. The heat engine 10 is connected to an exhaust line 11 for the evacuation of the burnt gases produced by the operation of the heat engine 10.
[0023] La ligne d'échappement 1 1 comprend un organe de dépollution 12 de polluant gazeux, par exemple un catalyseur d’oxydation ou un catalyseur trois-voies. Le catalyseur trois-voies 12 permet notamment de réduire les oxydes d'azote en azote et en dioxyde de carbone, d'oxyder les monoxydes de carbone en dioxyde de carbone, et les hydrocarbures imbrûlés en dioxyde de carbone et en eau.
[0024] La ligne d'échappement 1 1 comprend en outre un filtre à particules 13 pour filtrer des particules de suies dans les gaz d'échappement du moteur thermique 10. Le filtre à particules 13 est adapté à la filtration de particules de suies provenant de la combustion du carburant. The exhaust line 1 1 comprises a pollution control member 12 of gaseous pollutant, for example an oxidation catalyst or a three-way catalyst. The three-way catalyst 12 makes it possible in particular to reduce the oxides of nitrogen to nitrogen and to carbon dioxide, to oxidize the carbon monoxides to carbon dioxide, and the unburnt hydrocarbons to carbon dioxide and to water. The exhaust line 1 1 further comprises a particulate filter 13 for filtering soot particles in the exhaust gases of the heat engine 10. The particulate filter 13 is suitable for filtering soot particles from fuel combustion.
[0025] Dans le filtre à particules 13, les gaz d'échappement traversent la matière composant le filtre à particules 13. Ainsi, lorsque le filtre à particules 13 est formé de canaux, chacun de ces canaux comprend une extrémité bouchée, de sorte que les gaz d'échappement s'écoulant dans le filtre à particules 13 passent de canaux en canaux, en traversant les parois des différents canaux du filtre à particules 13 pour sortir du filtre à particules 13. Le filtre à particules 13 pourra être à base d'une matrice céramique poreuse, par exemple en cordiérite, mullite, titanate d'aluminium ou carbure de silicium. S'il y a lieu, l'organe de dépollution 12 et le filtre à particules 13 pourront être implantés à l'intérieur d'une même enveloppe 15. In the particulate filter 13, the exhaust gases pass through the material making up the particulate filter 13. Thus, when the particulate filter 13 is formed of channels, each of these channels comprises a plugged end, so that the exhaust gases flowing in the particle filter 13 pass from channel to channel, passing through the walls of the various channels of the particle filter 13 to exit the particle filter 13. The particle filter 13 may be based on 'a porous ceramic matrix, for example of cordierite, mullite, aluminum titanate or silicon carbide. If necessary, the depollution unit 12 and the particulate filter 13 may be located inside the same envelope 15.
[0026] La ligne d'échappement 1 1 est également munie d'un capteur 16, dit capteur de contrepression, pour la mesure de pression différentielle entre l'amont et l'aval du filtre à particules 13 à partir de laquelle il est possible de déduire une masse de suies accumulées. A cet effet, le capteur 16 est connecté en amont et en aval du filtre à particules 13 respectivement par l'intermédiaire d'un piquage amont 16.1 et d'un piquage aval 16.2. Une cartographie permet d'établir une corrélation entre la mesure de pression différentielle et la masse de suies dans le filtre à particules 13. The exhaust line 1 1 is also provided with a sensor 16, said back pressure sensor, for the differential pressure measurement between the upstream and downstream of the particulate filter 13 from which it is possible to deduce a mass of accumulated soot. To this end, the sensor 16 is connected upstream and downstream of the particulate filter 13 respectively by means of an upstream connection 16.1 and a downstream connection 16.2. A map makes it possible to establish a correlation between the differential pressure measurement and the mass of soot in the particulate filter 13.
[0027] Un calculateur 17, par exemple le calculateur moteur ou un calculateur dédié comporte une mémoire stockant des instructions logicielles pour la mise en oeuvre du procédé selon l'invention de diagnostic de la présence de gel dans un piquage 16.1 , 16.2 du capteur de contrepression 16. A computer 17, for example the engine computer or a dedicated computer comprises a memory storing software instructions for the implementation of the method according to the invention for diagnosing the presence of frost in a tap 16.1, 16.2 of the sensor of back pressure 16.
[0028] A cet effet, le calculateur 17 reçoit en entrée une mesure de la contrepression dP aux bornes du filtre 13 retournée par le capteur 16, une estimation du débit volumique Qvol des gaz d’échappement en amont du filtre à particules 13, ainsi qu’une température extérieure car le diagnostic est activé de préférence uniquement pour des températures inférieures à 0 °Q pour exclure une fausse détection qui serait due à un encrassement autre que par le gel. Le calculateur 17
est apte à générer en sortie un signal de défaut F_def à l'état 1 en cas de détection de la présence de gel dans un piquage 16.1 , 16.2. To this end, the computer 17 receives as input a measurement of the back pressure dP across the filter 13 returned by the sensor 16, an estimate of the volume flow Qvol of the exhaust gases upstream of the particulate filter 13, as well than an outside temperature because the diagnostic is preferably activated only for temperatures below 0 ° Q to exclude false detection which would be due to fouling other than freezing. Calculator 17 is able to generate at output a fault signal F_def in state 1 in the event of detection of the presence of frost in a tap 16.1, 16.2.
[0029] On décrit ci-après, en référence avec la figure 2, les différentes étapes du procédé de diagnostic selon l’invention. [0029] The various steps of the diagnostic process according to the invention are described below with reference to FIG. 2.
[0030] Dans une étape 101 , le calculateur 17 calcule un gradient dPdV de la contrepression dP retournée par le capteur de contrepression 16 en fonction du débit volumique Qvol des gaz d’échappement en amont du filtre à particules 13 exprimé en KPa/(m3/s). In a step 101, the computer 17 calculates a gradient dPdV of the back pressure dP returned by the back pressure sensor 16 as a function of the volume flow Qvol of the exhaust gases upstream of the particulate filter 13 expressed in KPa / (m 3 / s).
[0031 ] La relation entre ces deux grandeurs physiques (contrepression dP et débit volumique Qvol) peut être approximée par un polynôme d’ordre 2 ou quadratique, mais il existe une plage PJin de débit volumique dans laquelle la relation peut être considérée comme linéaire, avec des erreurs acceptables, tel que cela est illustré sur la figure 3. The relationship between these two physical quantities (backpressure dP and volume flow Qvol) can be approximated by a polynomial of order 2 or quadratic, but there is a range PJin of volume flow in which the relationship can be considered as linear, with acceptable errors, as shown in Figure 3.
[0032] La méthode de calcul du gradient dPdV consiste à prendre un échantillon de points de taille N, calibrable par exemple entre 800 et 1000. Chaque point est un couple de mesures: une mesure de contrepression dP exprimée en mbar et une mesure de débit volumique Qvol en amont du filtre à particules 13 exprimée en m3/s. On calcule ensuite une régression linéaire sur ces points, notamment par la méthode des moindres carrés. The dPdV gradient calculation method consists in taking a sample of points of size N, calibratable for example between 800 and 1000. Each point is a couple of measurements: a measurement of back pressure dP expressed in mbar and a flow measurement volume Qvol upstream of the particle filter 13 expressed in m 3 / s. A linear regression is then calculated on these points, in particular by the least squares method.
[0033] De préférence, toutes les mesures de contrepression dP et débit volumique Qvol ne sont pas retenues pour le calcul du gradient dPdV. Un critère est appliqué afin de prendre en compte seulement les mesures qui sont obtenues en conditions de fonctionnement stabilisé du moteur thermique. Par "conditions de fonctionnement stabilisé", on entend les conditions de fonctionnement du moteur thermique pour lesquelles le débit des gaz d’échappement Qvol ne varie pas brusquement, autrement dit, en absence d’accélérations ou de freinages brusques. Preferably, all the measurements of back pressure dP and volume flow rate Qvol are not used for the calculation of the gradient dPdV. A criterion is applied in order to take into account only the measurements which are obtained under stabilized operating conditions of the heat engine. By "stabilized operating conditions" is meant the operating conditions of the thermal engine for which the flow rate of the exhaust gases Qvol does not vary abruptly, in other words, in the absence of sudden acceleration or braking.
[0034] Ce critère est vérifié en calculant la dérivée du débit volumique Qvol des gaz d'échappement en amont du filtre 13 qui indique le taux de variation de ce débit en fonction du temps, et en s'assurant que cette valeur est inférieure à une borne maximum, par exemple de l’ordre de 0.05 m3/s2. Par "de l'ordre de", on entend une
variation de plus ou moins 10% autour de cette valeur. Grâce à ce critère, il est possible d'améliorer la précision du calcul du gradient dPdV. Sur la figure 3, les points stabilisés qui sont retenus pour le calcul sont représentés par des croix; tandis que les points transitoires qui ne sont pas retenus pour le calcul sont représentés par des ronds. This criterion is verified by calculating the derivative of the volume flow Qvol of the exhaust gases upstream of the filter 13 which indicates the rate of change of this flow as a function of time, and by ensuring that this value is less than a maximum limit, for example of the order of 0.05 m 3 / s 2 . By "of the order of" is meant a variation of plus or minus 10% around this value. Thanks to this criterion, it is possible to improve the precision of the calculation of the dPdV gradient. In FIG. 3, the stabilized points which are retained for the calculation are represented by crosses; while the transient points which are not retained for the calculation are represented by circles.
[0035] Au cours d'une étape 102, on définit un intervalle de temps I dans lequel est observé le comportement du calcul du gradient dPdV Cet intervalle de temps I, encore désignée fenêtre d’observation, est prévu suffisamment court pour exclure une fausse détection qui serait due à un encrassement autre que par le gel. En effet, un encrassement autre que par le gel, par exemple par les suies ou les cendres, provoque une évolution lente du gradient de contrepression. Une évolution plus rapide de ce gradient de contrepression pendant cet intervalle de temps I est révélateur d’une apparition de gel dans le piquage. Cet intervalle de temps I est par exemple compris entre deux et trois minutes. During a step 102, a time interval I is defined in which the behavior of the calculation of the gradient dPdV is observed. This time interval I, also referred to as the observation window, is provided sufficiently short to exclude a false detection which would be due to a fouling other than by freezing. In fact, fouling other than by freezing, for example by soot or ash, causes a slow change in the backpressure gradient. A faster evolution of this backpressure gradient during this time interval I is indicative of the appearance of gel in the nozzle. This time interval I is for example between two and three minutes.
[0036] Au cours d'une étape 103, une valeur de référence du gradient dPdV_ref est mémorisée au début de chaque intervalle I et maintenue tout le long de l’intervalle I. Au cours de l'intervalle de temps I, le calculateur 17 calcule également des valeurs de gradient courant (ou instantané) dPdVJnst. Le calculateur 17 réalise donc deux calculs différents, à savoir le calcul du gradient courant dPdVJnst et le gradient de référence dPdV_ref figé au début de l’intervalle de temps I. During a step 103, a reference value of the gradient dPdV_ref is stored at the start of each interval I and maintained throughout the interval I. During the time interval I, the computer 17 also calculates current (or instantaneous) gradient values dPdVJnst. The computer 17 therefore performs two different calculations, namely the calculation of the current gradient dPdVJnst and the reference gradient dPdV_ref frozen at the start of the time interval I.
[0037] Au cours d'une étape 104, le calculateur 17 calcule le ratio R_dPdV entre le gradient courant dPdVJnst et le gradient de référence dPdV_ref, soit R_dPdV= d Pd V J nst/d Pd V_ref . During a step 104, the computer 17 calculates the ratio R_dPdV between the current gradient dPdVJnst and the reference gradient dPdV_ref, ie R_dPdV = d Pd V J nst / d Pd V_ref.
[0038] Au cours d'une étape 105, le ratio R_dPdV est comparé avec un seuil minimum Smin et un seuil maximum Smax. Le seuil minimum Smin est par exemple égal à 0.5 tandis que le seuil maximum Smax est par exemple égal à 2. During a step 105, the ratio R_dPdV is compared with a minimum threshold Smin and a maximum threshold Smax. The minimum threshold Smin is for example equal to 0.5 while the maximum threshold Smax is for example equal to 2.
[0039] Le résultat de cette comparaison détermine le résultat du diagnostic. En effet, dans le cas où le ratio est compris entre le seuil minimum Smin et le seuil maximum Smax, alors on en déduit qu'il n'y a pas de présence de gel dans les piquages 16.1 , 16.2 du capteur de contrepression 16. Dans le cas où le ratio n'est pas compris entre le seuil minimum Smin et le seuil maximum Smax, alors on en déduit qu'il y
a une présence de gel dans un piquage 16.1 , 16.2 du capteur de contrepression 16. [0039] The result of this comparison determines the result of the diagnosis. Indeed, in the case where the ratio is between the minimum threshold Smin and the maximum threshold Smax, then we deduce that there is no presence of gel in the nozzles 16.1, 16.2 of the backpressure sensor 16. If the ratio is not between the minimum threshold Smin and the maximum threshold Smax, then we deduce that there is has a presence of gel in a nozzle 16.1, 16.2 of the backpressure sensor 16.
[0040] La figure 4 montre une évolution temporelle des signaux obtenus lors d’une mise en oeuvre du procédé selon l’invention de détection de présence de gel dans un piquage 16.1 , 16.2 du capteur de contrepression 16. On distingue l'évolution temporelle du gradient courant dPdVJnst, du gradient de référence dPdV_ref, du ratio R_dPdV, ainsi que la variable d’état F_def ("flag" en anglais) prenant la valeur 1 en cas de défaut. Les points P indiquent les instants en début d'intervalle de temps I auxquels est calculé le gradient de référence dPdV_ref. Figure 4 shows a temporal evolution of the signals obtained during an implementation of the method according to the invention for detecting the presence of gel in a tap 16.1, 16.2 of the backpressure sensor 16. We distinguish the temporal evolution the current gradient dPdVJnst, the reference gradient dPdV_ref, the R_dPdV ratio, as well as the state variable F_def ("flag") taking the value 1 in the event of a fault. The points P indicate the instants at the start of time interval I at which the reference gradient dPdV_ref is calculated.
[0041 ] Au cours des deux premiers intervalles de temps I, le ratio R_dPdV est compris entre le seuil minimum Smin et le seuil maximum Smax. Au cours du troisième intervalle de temps I, on observe une évolution forte du ratio R_dPdV qui dépasse le seuil maximum Smax autorisé. Cela indique une anomalie dans la mesure de la contrepression du filtre à particules 13, provoquée probablement par la présence d’un bouchon de gel dans un piquage 16.1 , 16.2. Le signal de défaut F_def passe alors à l'état 1 . During the first two time intervals I, the ratio R_dPdV is between the minimum threshold Smin and the maximum threshold Smax. During the third time interval I, a strong change in the R_dPdV ratio is observed, which exceeds the maximum authorized Smax threshold. This indicates an anomaly in the measurement of the back pressure of the particulate filter 13, probably caused by the presence of a gel plug in a nozzle 16.1, 16.2. The fault signal F_def then changes to state 1.
[0042] En effet, le paramètre dPdVJnst n’est pas censé évoluer rapidement en conditions normales de fonctionnement, c’est-à-dire sans perturbations de la mesure de contrepression. Le paramètre dPdVJnst évolue avec le stockage de particules dans le filtre 13 d’une façon lente du fait de la vitesse relativement faible de production de particules par le moteur thermique 10. [0042] In fact, the dPdVJnst parameter is not supposed to change rapidly under normal operating conditions, that is to say without disturbing the back pressure measurement. The dPdVJnst parameter changes with the storage of particles in the filter 13 in a slow manner due to the relatively low speed of production of particles by the heat engine 10.
[0043] Par exemple, pour un moteur à allumage commandé, pour doubler sa valeur (R_dPdV= 2) il lui faudrait entre 2 et 4 heures en considérant qu’on se trouve dans des conditions critiques vis-à-vis de la production de particules polluantes. Une évolution plus rapide que celle-ci indique nécessairement une anomalie dans l’acquisition de la pression différentielle entre les bornes amont et aval, typique de la présence d’un bouchon de gel dans un piquage 16.1 , 16.2. For example, for a spark ignition engine, to double its value (R_dPdV = 2) it would take between 2 and 4 hours considering that we are in critical conditions vis-à-vis the production of polluting particles. A faster development than this necessarily indicates an anomaly in the acquisition of the differential pressure between the upstream and downstream terminals, typical of the presence of a gel plug in a tap 16.1, 16.2.
[0044] Lorsque le ratio R_dPdV repasse à une valeur située entre le seuil minimum Smin et le seuil maximum Smax, il est considéré dans la plage "acceptable" et le diagnostic est réhabilité. Il est possible de prévoir une durée de confirmation Te de
la suppression du défaut avant de faire repasser le signal de défaut F_def à l'état 0 et recommencer à observer de nouveau l'évolution du ratio R_dPdV. When the R_dPdV ratio returns to a value situated between the minimum threshold Smin and the maximum threshold Smax, it is considered to be in the "acceptable" range and the diagnosis is rehabilitated. It is possible to provide a confirmation period Te of removal of the fault before returning the fault signal F_def to state 0 and again observing the development of the R_dPdV ratio.
[0045] En variante, il est possible d'analyser l'évolution, sur l'intervalle de temps I, de la valeur instantanée dPdVJnst par rapport à la valeur de référence dPdV_ref d'une autre façon que par le calcul d'un ratio R_dPdV. En variante, le ratio calculé est le ratio inverse de celui précédemment indiqué.
As a variant, it is possible to analyze the evolution, over the time interval I, of the instantaneous value dPdVJnst relative to the reference value dPdV_ref in another way than by calculating a ratio R_dPdV. As a variant, the calculated ratio is the inverse ratio of that previously indicated.
Claims
1 . Procédé de diagnostic de présence de gel dans un piquage (16.1 , 16.2) d'un capteur (16) de pression différentielle, dit capteur de contrepression, connecté en amont et en aval d'un filtre à particules (13) destiné à filtrer des gaz d’échappement d'un moteur thermique, caractérisé en ce que ledit procédé comporte: 1. Method for diagnosing the presence of frost in a tap (16.1, 16.2) of a differential pressure sensor (16), called a backpressure sensor, connected upstream and downstream of a particle filter (13) intended to filter exhaust gas from a heat engine, characterized in that said method comprises:
- une étape de définition d'un intervalle de temps (I), - a step of defining a time interval (I),
- une étape de calcul d'une valeur de référence (dPdV_ref) d'un gradient d'une contrepression (dP) du filtre à particules (13) retournée par le capteur de contrepression (16) en fonction d'un débit volumique (Qvol) des gaz d'échappement en amont du filtre à particules (13), et - a step of calculating a reference value (dPdV_ref) of a gradient of a backpressure (dP) of the particle filter (13) returned by the backpressure sensor (16) as a function of a volume flow (Qvol ) exhaust gases upstream of the particulate filter (13), and
- une étape d'analyse d'une évolution, sur l'intervalle de temps (I), d'une valeur instantanée (dPdVJnst) du gradient de la contrepression (dP) du filtre à particules (13) retournée par le capteur de contrepression (16) en fonction du débit volumique (Qvol) des gaz d'échappement en amont du filtre à particules (13) par rapport à la valeur de référence (dPdV_ref) précédemment calculée pour en déduire la présence ou non de gel dans un piquage (16.1 , 16.2) du capteur de contrepression (16). - a step of analyzing an evolution, over the time interval (I), of an instantaneous value (dPdVJnst) of the backpressure gradient (dP) of the particulate filter (13) returned by the backpressure sensor (16) as a function of the volume flow rate (Qvol) of the exhaust gases upstream of the particulate filter (13) compared to the reference value (dPdV_ref) previously calculated to deduce the presence or absence of gel in a nozzle ( 16.1, 16.2) of the backpressure sensor (16).
2. Procédé selon la revendication 1 , caractérisé en ce que l'étape d'analyse comporte: 2. Method according to claim 1, characterized in that the analysis step comprises:
- une étape de calcul d'un ratio (R_dPdV) entre la valeur instantanée (dPdVJnst) du gradient de la contrepression et la valeur de référence (dPdV_ref) précédemment calculée, - a step of calculating a ratio (R_dPdV) between the instantaneous value (dPdVJnst) of the backpressure gradient and the reference value (dPdV_ref) previously calculated,
- une étape de comparaison du ratio (R_dPdV) calculé avec un seuil maximum (Smax) et un seuil minimum (Smin), et - a step of comparing the ratio (R_dPdV) calculated with a maximum threshold (Smax) and a minimum threshold (Smin), and
- une étape de détermination de la présence de gel ou non dans un piquage (16.1 , 16.2) en fonction d'un résultat de la comparaison précédemment réalisée. - a step of determining the presence of gel or not in a stitching (16.1, 16.2) as a function of a result of the comparison carried out previously.
3. Procédé selon la revendication 1 ou 2, caractérisé en ce que la valeur de référence (dPdV_ref) est calculée au début de l'intervalle de temps (I). 3. Method according to claim 1 or 2, characterized in that the reference value (dPdV_ref) is calculated at the start of the time interval (I).
4. Procédé selon l'une quelconque des revendications 1 à 3, caractérisé en ce qu'une méthode de calcul du gradient de la contrepression (dP) du filtre à particules (13) en fonction du débit volumique (Qvol) des gaz d'échappement
en amont du filtre à particules (13) consiste à prendre un échantillon de points de taille N, chaque point étant un couple de mesures comprenant une mesure de contrepression (dP) retournée par le capteur (16) et une mesure de débit volumique (Qvol) en amont du filtre à particules (13), et à calculer une régression linéaire sur ces points. 4. Method according to any one of claims 1 to 3, characterized in that a method of calculating the gradient of the backpressure (dP) of the particulate filter (13) as a function of the volume flow (Qvol) of the gases of exhaust upstream of the particulate filter (13) consists in taking a sample of points of size N, each point being a pair of measurements comprising a back pressure measurement (dP) returned by the sensor (16) and a volume flow measurement (Qvol ) upstream of the particulate filter (13), and to calculate a linear regression on these points.
5. Procédé selon la revendication 4, caractérisé en ce qu’il comporte l’étape de retenir uniquement les mesures de contrepression (dP) et de débit volumique (Qvol) qui ont été obtenues en conditions de stabilité de fonctionnement du moteur thermique. 5. Method according to claim 4, characterized in that it comprises the step of retaining only the back pressure (dP) and volume flow (Qvol) measurements which were obtained under conditions of stable operation of the heat engine.
6. Procédé selon la revendication 5, caractérisé en ce que les mesures de contrepression (dP) et de débit volumique (Qvol) sont considérées comme ayant été obtenues dans des conditions de stabilité de fonctionnement du moteur thermique (10) lorsqu’une dérivée du débit volumique (Qvol) des gaz d’échappement en amont du filtre à particules (13) est inférieure à une borne maximum. 6. Method according to claim 5, characterized in that the back pressure (dP) and volume flow (Qvol) measurements are considered to have been obtained under conditions of operating stability of the heat engine (10) when a derivative of the volume flow rate (Qvol) of the exhaust gases upstream of the particulate filter (13) is less than a maximum limit.
7. Procédé selon l’une quelconque des revendications 1 à 6, caractérisé en ce que l’intervalle de temps (I) est compris entre 2 et 3 minutes. 7. Method according to any one of claims 1 to 6, characterized in that the time interval (I) is between 2 and 3 minutes.
8. Procédé selon l'une quelconque des revendications 1 à 7, caractérisé en ce qu'il est mis en oeuvre uniquement si une température extérieure est inférieure à 0°C. 8. Method according to any one of claims 1 to 7, characterized in that it is implemented only if an outside temperature is below 0 ° C.
9. Procédé selon la revendication 2, caractérisé en ce que suite à un défaut lié à une détection de la présence de gel dans un piquage (16.1 , 16.2), ledit procédé de diagnostic sera réhabilité lorsque le ratio (R_dPdV) repasse à une valeur située entre le seuil minimum (Smin) et le seuil maximum (Smax). 9. The method of claim 2, characterized in that following a fault linked to a detection of the presence of gel in a nozzle (16.1, 16.2), said diagnostic method will be rehabilitated when the ratio (R_dPdV) returns to a value. located between the minimum threshold (Smin) and the maximum threshold (Smax).
10. Calculateur (17) comportant une mémoire stockant des instructions logicielles pour la mise en oeuvre du procédé tel que défini selon l’une quelconque des revendications précédentes/
10. Computer (17) comprising a memory storing software instructions for implementing the method as defined in any one of the preceding claims /
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Application Number | Priority Date | Filing Date | Title |
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FR1903564A FR3094752B1 (en) | 2019-04-03 | 2019-04-03 | PROCESS FOR DIAGNOSING THE PRESENCE OF FROST IN A PITCH OF A DIFFERENTIAL PRESSURE SENSOR |
FR1903564 | 2019-04-03 |
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WO2020201648A1 true WO2020201648A1 (en) | 2020-10-08 |
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PCT/FR2020/050478 WO2020201648A1 (en) | 2019-04-03 | 2020-03-09 | Method for diagnosing the presence of frost in the tapping of a differential pressure sensor |
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WO (1) | WO2020201648A1 (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE102020214627A1 (en) | 2020-11-20 | 2022-05-25 | Volkswagen Aktiengesellschaft | Method for detecting a malfunction of a differential pressure sensor or a pair of pressure sensors |
US11781944B2 (en) | 2021-11-30 | 2023-10-10 | Cummins Inc. | Detection of delta pressure sensor icing |
Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE102005034270A1 (en) * | 2005-07-22 | 2007-01-25 | Robert Bosch Gmbh | Method for diagnosing a differential pressure sensor arranged in an exhaust gas region of a combustion engine comprises evaluating the dynamic behavior of a differential pressure signal as a result of a change in exhaust gas pressure |
DE102007000892A1 (en) * | 2006-11-14 | 2008-07-31 | Denso Corp., Kariya | Apparatus for diagnosing abnormal operation of an apparatus for detecting a pressure difference for an engine exhaust system |
US20090084097A1 (en) * | 2007-10-01 | 2009-04-02 | Honda Motor Co., Ltd. | Exhaust gas purifying apparatus for internal combustion engine |
EP2426326A1 (en) | 2010-09-02 | 2012-03-07 | Peugeot Citroën Automobiles SA | Particle filter with three catalytic coatings |
DE102012207891A1 (en) * | 2011-05-19 | 2012-11-22 | GM Global Technology Operations LLC (n.d. Ges. d. Staates Delaware) | Systems and methods for detecting a pressure sensor interruption |
DE102014209718A1 (en) * | 2014-05-22 | 2015-11-26 | Robert Bosch Gmbh | Method and diagnostic unit for diagnosing a differential pressure sensor |
US20180087432A1 (en) * | 2016-09-29 | 2018-03-29 | Audi Ag | Method for Diagnosing a Measurement of a Pressure Difference |
WO2019012196A1 (en) * | 2017-07-12 | 2019-01-17 | Psa Automobiles Sa | Method for estimating a charge of the controlled ignition combustion engine particulate filter |
-
2019
- 2019-04-03 FR FR1903564A patent/FR3094752B1/en active Active
-
2020
- 2020-03-09 WO PCT/FR2020/050478 patent/WO2020201648A1/en active Application Filing
Patent Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE102005034270A1 (en) * | 2005-07-22 | 2007-01-25 | Robert Bosch Gmbh | Method for diagnosing a differential pressure sensor arranged in an exhaust gas region of a combustion engine comprises evaluating the dynamic behavior of a differential pressure signal as a result of a change in exhaust gas pressure |
DE102007000892A1 (en) * | 2006-11-14 | 2008-07-31 | Denso Corp., Kariya | Apparatus for diagnosing abnormal operation of an apparatus for detecting a pressure difference for an engine exhaust system |
US20090084097A1 (en) * | 2007-10-01 | 2009-04-02 | Honda Motor Co., Ltd. | Exhaust gas purifying apparatus for internal combustion engine |
EP2426326A1 (en) | 2010-09-02 | 2012-03-07 | Peugeot Citroën Automobiles SA | Particle filter with three catalytic coatings |
DE102012207891A1 (en) * | 2011-05-19 | 2012-11-22 | GM Global Technology Operations LLC (n.d. Ges. d. Staates Delaware) | Systems and methods for detecting a pressure sensor interruption |
DE102014209718A1 (en) * | 2014-05-22 | 2015-11-26 | Robert Bosch Gmbh | Method and diagnostic unit for diagnosing a differential pressure sensor |
US20180087432A1 (en) * | 2016-09-29 | 2018-03-29 | Audi Ag | Method for Diagnosing a Measurement of a Pressure Difference |
WO2019012196A1 (en) * | 2017-07-12 | 2019-01-17 | Psa Automobiles Sa | Method for estimating a charge of the controlled ignition combustion engine particulate filter |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE102020214627A1 (en) | 2020-11-20 | 2022-05-25 | Volkswagen Aktiengesellschaft | Method for detecting a malfunction of a differential pressure sensor or a pair of pressure sensors |
US11781944B2 (en) | 2021-11-30 | 2023-10-10 | Cummins Inc. | Detection of delta pressure sensor icing |
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FR3094752A1 (en) | 2020-10-09 |
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