EP3870819B1 - Method for early opening of a cold thermostat in an engine cooling system - Google Patents

Method for early opening of a cold thermostat in an engine cooling system Download PDF

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Publication number
EP3870819B1
EP3870819B1 EP19786378.0A EP19786378A EP3870819B1 EP 3870819 B1 EP3870819 B1 EP 3870819B1 EP 19786378 A EP19786378 A EP 19786378A EP 3870819 B1 EP3870819 B1 EP 3870819B1
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European Patent Office
Prior art keywords
temperature
opening
thermostat
fluid
command
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EP19786378.0A
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German (de)
French (fr)
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EP3870819A1 (en
Inventor
Michel ANGELI
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Stellantis Auto SAS
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PSA Automobiles SA
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Publication of EP3870819A1 publication Critical patent/EP3870819A1/en
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01P—COOLING OF MACHINES OR ENGINES IN GENERAL; COOLING OF INTERNAL-COMBUSTION ENGINES
    • F01P7/00—Controlling of coolant flow
    • F01P7/14—Controlling of coolant flow the coolant being liquid
    • F01P7/16—Controlling of coolant flow the coolant being liquid by thermostatic control
    • F01P7/167—Controlling of coolant flow the coolant being liquid by thermostatic control by adjusting the pre-set temperature according to engine parameters, e.g. engine load, engine speed
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01P—COOLING OF MACHINES OR ENGINES IN GENERAL; COOLING OF INTERNAL-COMBUSTION ENGINES
    • F01P2070/00—Details
    • F01P2070/04—Details using electrical heating elements

Definitions

  • the present invention relates to a method for early opening of a cold thermostat in a cooling system of a heat engine, advantageously of a motor vehicle.
  • the present invention also relates to a cooling system for the implementation of such an opening method, advantageously in a motor vehicle.
  • a heat engine cooling system comprises a main cooling circuit for circulation of a cooling fluid provided with at least one fluid temperature sensor, the main cooling circuit passing through the engine heat and drawing heat from it.
  • the cooling system also comprises a heat exchange circuit for cooling the fluid, this heat exchange circuit comprising at least one or more radiators.
  • a thermostat controlled by a control unit forming part of the cooling system, operates a closing and an at least partial opening of the heat exchange circuit.
  • the control unit has control means controlling the thermostat according to a regulation command as a function of at least one first predetermined set point temperature saved in memory means. There can be two setpoint temperatures with a low temperature and a high temperature setpoint.
  • cold thermostat in the context of the present invention, it is understood a thermostat which has two very different temperatures between the temperature of the cooling fluid in the main circuit and the temperature of the coolant in the heat exchange circuit.
  • a thermostat is a mechanical system which opens from a certain temperature of the cooling fluid and lets the fluid pass towards the radiator of the heat exchange circuit to be cooled.
  • a controlled thermostat is a thermomechanical system, which makes it possible to control the opening temperature of the heat exchange circuit or circuit of the radiator(s). It is thus possible to regulate the temperature of the cooling fluid.
  • At least two setpoint values are defined, among which a high regulation setpoint and a low regulation setpoint to find the best compromise between, on the one hand, the reduction of friction and the reduction of fuel dilution in the oil, which corresponds to the high regulation setpoint and, on the other hand, the thermomechanical behavior of the engine, which corresponds to the low regulation setpoint.
  • the thermostat consists of a wax cartridge. As the wax expands, it opens up the cooling fluid passage section. Controlling the thermostat consists of heating the wax, to shift the opening point to a lower temperature.
  • a cooling system control unit calculates, based on the setpoint to be reached and several other pieces of information, a pre-control, a proportional control, and an integral control. The sum of these three commands defines the command to be applied to the thermostat to respect the setpoint, also called regulation command.
  • the parameters for controlling the thermostat by the control unit are optimized to ensure the best follow-up of the set point, in steady state.
  • the two sides of the thermostat corresponding respectively to the main circuit and to the heat exchange circuit are at very different temperatures.
  • the side directed towards the heat engine and therefore towards the main circuit is in contact with a hot fluid while the side directed towards the radiator and the heat exchange circuit is in contact with a cold fluid, because the fluid has no still circulated through the radiator and the engine and was not supplied with hot fluid from the main circuit.
  • a positive overshoot of the fluid temperature with respect to the setpoint will be observed, followed by a negative overshoot in return.
  • the positive overshoot can lead to the activation of the cooling fan, which is detrimental in terms of consumption.
  • the document CN-A-107893697 describes a method for controlling an electronic thermostat of a fluid circulation cooling system of a motor vehicle engine.
  • the method provides for the monitoring of a fluid setpoint temperature.
  • the fluid setpoint temperature is corrected by a correction coefficient depending on the speed of the vehicle, on the gear ratio selected.
  • a temperature difference between the current temperature and the set temperature thus corrected is monitored and the opening of the thermostat is regulated according to the difference.
  • the disclosure of this document does not, however, relate to a large temperature difference existing between the fluid of the main circuit of the system passing through the heat engine and the fluid of the heat exchange circuit for cooling the fluid, this difference affecting the thermostat operation and efficiency.
  • the problem at the base of the present invention is, in a fluid cooling system of a heat engine with a controlled thermostat for the opening of a heat exchange circuit of the still cold fluid from 'a circuit main passing through the engine which is already hot, to correct the regulation control according to the state of the art by taking into account the temperature difference between the fluid of the main circuit and the fluid of the heat exchange circuit which is not yet sufficiently hot.
  • the present invention relates to a method for early opening of a cold controlled thermostat in a heat transfer fluid cooling system of a heat engine, the controlled thermostat effecting at least partial closing and opening of a circuit of heat exchange with respect to a main cooling circuit of the system, the thermostat being controlled by an opening regulation command based on a current temperature of the fluid and a setpoint temperature, a corrective command for opening the thermostat being established when a first difference between the fluid temperature in effect and the setpoint temperature is lower by less than a first predetermined temperature difference threshold and when at least one engine operating condition or at least one climatic condition has been recognized by experience as causing a temperature difference between the respective fluids of the heat exchange circuits.
  • a final thermostat opening command is established after comparison of the opening regulation command and of the corrective opening command, with a final opening percentage of the thermostat, the final opening command of the controlled thermostat being that of the two commands activating only the opening of the thermostat or that activating the opening of the thermostat with the most large percentage open becoming the final percentage open of the thermostat when both commands activate the opening of the thermostat.
  • the present invention provides for the implementation of a corrective thermostat opening control so that the temperature of the fluid in force does not exceed the setpoint temperature and then falls below the setpoint temperature, exceeding the setpoint temperature possibly causing an activation of cooling system fan, which is detrimental in terms of consumption.
  • a predetermined corrective command is then applied to the thermostat.
  • the difference is advantageously predetermined so that the thermostat is controlled before the regulation system by a regulation command itself controls the opening of the thermostat.
  • a temperature difference between the respective fluids of the heat exchange and main circuits above a temperature difference threshold between respective fluids was chosen to monitor at least one condition of operation of the engine or at least one external climatic condition which is experimentally known to cause a temperature difference between the respective fluids of the heat exchange and main circuits above a temperature difference threshold between respective fluids.
  • the regulation command proposes a higher opening percentage than the corrective command, a setpoint regulation is maintained. Conversely, if the regulation command proposes a lower opening percentage than the corrective command, the setpoint regulation, then not being active or not very active, can be replaced by the corrective command with its specific opening percentage. The most frequent case is however that the corrective command completely anticipates the regulation command which would not then have triggered, taken in isolation, an opening of the controlled thermostat.
  • the heat engine is a motor vehicle engine, said at least one operating condition of the heat engine being a driving condition of the motor vehicle.
  • said at least one driving condition is selected individually or in combination from the following driving conditions: a first opening of the thermostat after a cold engine start following a stoppage of at least 45 minutes, a speed of more than 80 km/ H of driving with the thermostat closed for a period of more than thirty minutes or said at least one climatic condition is selected individually or in combination from the following climatic conditions: an outside temperature of less than 5°C, rainy or windy weather.
  • the temperature of the fluid in the main circuit will rise rapidly while the temperature of the fluid in the heat exchange circuit remains cold, especially if the outside temperature is low and if the heat exchange circuit is highly ventilated or at least does not recover calories.
  • the final opening percentage is corrected downwards as a function of the temperature of the fluid, giving a corrected final opening percentage which is lower and lower the higher the temperature of the fluid increases.
  • the limited opening percentage is used to protect the opening means of the fluid heat exchange circuit, which is frequently a controlled thermostat.
  • a protection function of the controlled thermostat for which the control of the thermostat will be limited according to the temperature of the fluid. This function is not intended to avoid too sudden opening, the response time of the thermostat is 10 to 20 seconds, but to ensure the durability of the thermostat. To avoid too sudden opening of the thermostat, we will act on the regulator settings, and especially on the design of the thermostat, so that it opens gradually.
  • At least one deactivation condition is established to stop the activation of the corrective opening command.
  • a fluid temperature gradient being defined at a given instant, a gradient threshold being predetermined corresponding to an opening of the thermostat, a maximum duration of the corrective command being predetermined, a second temperature difference threshold being predetermined by being lower than the first temperature difference threshold and a third temperature difference threshold being predetermined by being greater than the first temperature difference threshold, said at least one deactivation condition is selected from among the following conditions taken individually or in combination : the temperature gradient equal to or less than the gradient threshold, a duration of application of the corrective command greater than the maximum duration, the difference in fluid temperature in force with the fluid setpoint temperature less than the second threshold or greater than the third threshold.
  • the fluid temperature difference is less than or equal to the first threshold, for example -10° C., this occurs if the fluid temperature setpoint increases.
  • the fluid temperature difference is greater than or equal to the second threshold, for example 5°C, this occurs if the fluid temperature set point decreases, or if the fluid temperature gradient is high, being greater for example than 0.5°C/s.
  • the regulation command is established by being the sum of a pre-command, an integral command and a proportional command.
  • the invention relates to a cooling system for a heat engine of a motor vehicle comprising a main cooling circuit for circulating a cooling fluid provided with at least one fluid temperature sensor and an exchange circuit heat for cooling the fluid, a controlled thermostat effecting at least partial closing and opening of the heat exchange circuit, a control unit having control means controlling the thermostat according to a regulation command as a function of at least one predetermined setpoint temperature saved in memory means, the system implementing such a method, the control unit comprising means for receiving the temperature of the fluid, means for calculating a difference in the temperature of the fluid with the setpoint temperature, means for storing a first predetermined temperature difference threshold, means for estimating a difference temperature between the respective fluids of the heat exchange and main circuits above a temperature difference threshold between respective fluids as a function of at least one driving condition or at least one external climatic condition identified by detection means, means for establishing a corrective thermostat opening command, characterized in that the control unit comprises means for determining an opening percentage of the controlled thermostat for the regulation command and for the order corrective
  • Such a cooling system in particular through its control unit, aims to anticipate the control of a cold thermostat, with respect to the cooling fluid temperature regulation setpoint function.
  • the anticipation of opening is done on a condition of difference between the temperature of the fluid in force and the setpoint temperature which can then drop, but this is not necessarily the case, as well as an estimate of a thermostat cold with two different temperatures on the side of the main circuit and the heat exchange circuit.
  • Gains in quality and performance are thus obtained, with a gain in consumption, because no untimely activation of the cooling fan in the heat exchange circuit.
  • a gain in durability of the radiator of the heat exchange circuit is also obtained by limiting variations in fluid temperature.
  • the present invention relates to a method for early opening of a cold controlled thermostat in a heat transfer fluid cooling system of a heat engine.
  • the controlled thermostat performs at least partial closing and opening of a heat exchange circuit with respect to a main cooling circuit of the system, for example according to various degrees of opening or a single degree of complete opening.
  • a cold controlled thermostat means that the temperature of the fluid Tf of the heat exchange circuit is low having not had time to heat up and is close to the temperature in force Tf outside and even lower while the temperature of the fluid Tf of the main circuit begins to heat up due to the operation of the heat engine, in particular the driving of a motor vehicle propelled by the heat engine, which means that there is a large difference in temperature referenced dT on both sides of the thermostat, advantageously greater at 20°C.
  • the thermostat is controlled by an opening regulation command Creg from a current temperature Tf of the fluid and a setpoint temperature Tcons.
  • a fluid temperature regulator module 1 delivers a pre-command preC, a proportional command Cprop and an integral command Cint from a fluid temperature and a regulation setpoint temperature Tcons.
  • the pre-command preC, the proportional command Cprop and the integral command Cint are summed in a summing module 2 to give a regulation command Creg.
  • a corrective command Ccor for opening the thermostat is established, totally independent of the regulation command Creg. This is implemented, according to a first condition, when a difference between the fluid temperature Tf in force and the setpoint temperature Tcons is less than a first predetermined temperature difference threshold, this first threshold being referenced S1 at the figure 1 .
  • this is implemented, according to a second condition, when at least one engine operating condition or at least one external climatic condition has previously been recognized by experience as causing a temperature difference dT between the respective fluids of the circuits d heat and main exchange above a temperature difference threshold between respective fluids.
  • the difference is taken between the setpoint temperature Tcons and a temperature selected a few degrees below the regulation setpoint temperature Tcons, for example from 1 to 10°C less than the set temperature Tset.
  • This selected temperature can be chosen so that the thermostat is controlled before the regulation command Creg is effective and itself controls the thermostat.
  • an activation module 3 of the corrective command Ccor performs an activation of this corrective command Ccor from a fluid temperature Tf in effect, from a regulation setpoint temperature Tcons, from a fluid temperature difference equal to the fluid temperature subtracted by the regulation setpoint temperature and a temperature difference dT between the two sides of the thermostat, i.e. between the fluid temperature in the main circuit and the fluid temperature in the heat exchange circuit.
  • this temperature difference dT between the two sides of the thermostat cannot be easily measured, it is considered at least one operating condition of the motor or at least one condition outdoor climate recognized as being able to cause a difference greater than a temperature difference threshold on both sides of the predetermined thermostat.
  • the activation module 3 of the corrective command Ccor then sends an activation request act.
  • the heat engine can be a motor vehicle engine.
  • said at least one operating condition of the heat engine can be a driving condition of the motor vehicle.
  • the driving condition(s) can be selected individually or in combination from the following driving conditions: a first opening of the thermostat after a cold engine start following a stoppage of at least 45 minutes, which gives the time for the engine to cool almost completely, a speed of more than 80 km/h driving with the thermostat closed for a period of more than thirty minutes, which can lead to a pronounced cooling of the fluid in the heat exchange circuit and vice versa to a consequent heating of the main circuit fluid.
  • the climatic condition(s) can be selected individually or in combination from the following climatic conditions: an outside temperature of less than 5° C., rainy or windy weather.
  • one or more driving conditions with one or more climatic conditions. For example, when starting after a shutdown period of 45 minutes with an outside temperature below 5°C, it is very likely that the fluid in the heat exchange circuit is cold whereas the fluid in the main circuit will heat up for taxiing thermostat closed.
  • the activation request act sent by the activation module 3 of the corrective command Ccor is transmitted to a generation module 4 of a corrective command Ccor.
  • the generation module 4 of a corrective command Ccor can receive, on the other hand, a deactivation request desact originating from a module 5 for deactivation of the corrective command Ccor.
  • At least one deactivation condition can be established to stop the activation of the corrective opening Ccor command.
  • the deactivation module 5 sends, if necessary, a deactivation request deact according to a fluid temperature, a regulation setpoint temperature Tcons, a duration of the corrective command Ccor in comparison with a predetermined duration maximum of the corrective command Ccor, of a temperature gradient GT defined at a given instant, a gradient threshold being predetermined to correspond to an opening of the thermostat, of a second temperature difference in comparison with a second threshold S2 of predetermined temperature difference being lower than the first temperature difference threshold S1 and a third temperature difference in comparison with a third temperature difference threshold S3 predetermined being greater than the first temperature difference threshold S1.
  • the deactivation condition(s) can be selected from the following conditions taken individually or in combination: the temperature gradient GT being equal to or less than the gradient threshold, the duration of application D of the corrective command Ccor being greater than the maximum duration of the corrective command Ccor, the temperature difference in force Tf of the fluid with the setpoint temperature Tcons of the fluid being lower than the second threshold S2 or being higher than the third threshold S3.
  • the temperature gradient threshold GT can be equal to ⁇ 0.3° C./s, the temperature gradient GT being equal to or less than the gradient threshold for a deactivation.
  • the duration of application D of the corrective command Ccor may have exceeded a maximum predetermined duration of the corrective command Ccor of 20 seconds for a deactivation.
  • a temperature difference in force Tf of fluid with the setpoint temperature Tcons of fluid lower than the second threshold S2, for example -10° C., can also be a deactivation condition. This can happen, for example, if the fluid setpoint temperature increases.
  • a temperature difference in force Tf of fluid with the setpoint temperature Tcons of fluid greater than the third threshold S3 for example by 5° C. can be another deactivation condition. This occurs if the fluid setpoint temperature decreases or if the fluid temperature gradient GT is high, for example being greater than 0.5° C./s.
  • the generation module 4 sends a corrective command Ccor to a comparison module 6 also receiving a command regulation Creg from the summing module 2.
  • Temperature differences between the fluid temperature Tf in effect and the setpoint temperature Tcons are defined by subtracting the setpoint temperature Tcons from the fluid temperature Tf in effect.
  • a final command Cfin for opening the thermostat can be established after comparing the regulation command Creg for opening and the corrective command Ccor for opening in the comparison module 6.
  • the final command Cfin d' opening of the thermostat can integrate a final opening percentage of the thermostat.
  • the final command Cfin opening of the controlled thermostat is the one activating the opening of the thermostat with the greatest percentage of opening.
  • FIG. 2 shows four scenarios of implementation of the regulation method according to an embodiment of the present invention, the scenarios being shown superimposed two by two on this figure 2 .
  • the first scenario is in the upper left part of the figure 2
  • the second scenario being in the upper part to the right of the figure 2
  • the third scenario is in the lower left part of the figure 2
  • the fourth scenario is in the lower right part of the figure 2 .
  • the values S1, S2 and S3 are respectively the first, second and third thresholds previously mentioned, the second temperature difference threshold S2 being lower than the first temperature difference threshold S1 and the third temperature difference threshold S3 being greater than the first temperature difference threshold S1.
  • the temperature in force Tf of the fluid does not reach the setpoint temperature Tcons and the corrective command Ccor is stopped.
  • the temperature in force Tf of the fluid begins to rise without its difference with the setpoint temperature Tcons exceeding the first threshold S1.
  • the vertical arrow pointing down indicates a drop in temperature.
  • the drop in the setpoint temperature Tcons activates the regulation and the regulation command Creg while maintaining the opening of the thermostat.
  • the corrective command Ccor has been stopped because the temperature difference in force Tf of the fluid with the setpoint temperature Tcons of the fluid is greater than the third threshold S3, which is shown by the arrow of the third threshold S3 not reaching the curve of the effective temperature Tf of the fluid.
  • the setpoint temperature Tcons is then increased without implementing the regulation command Creg, which leads to the stopping of the corrective command Ccor.
  • the corrective command Ccor is stopped because the temperature difference in force Tf of the fluid with the setpoint temperature Tcons of the fluid is greater than the third threshold S3, which is shown by the arrow of the third threshold S3 not reaching the curve of the effective temperature Tf of the fluid.
  • the Creg regulation command continues to be activated.
  • the final opening percentage of the thermostat can be corrected downwards according to the temperature of the fluid Tf by giving a corrected final opening percentage being lower and lower the higher the temperature of the fluid Tf increases, this to protect the thermostat.
  • the invention relates to a cooling system for a heat engine of a motor vehicle comprising a main cooling circuit for circulation of a cooling fluid provided with at least one fluid temperature sensor Tf and a heat exchange for fluid cooling.
  • a controlled thermostat operates at least partial closing and opening of the heat exchange circuit.
  • a control unit has control means controlling the thermostat according to a regulation command Creg as a function of at least one predetermined set point temperature Tcons saved in memory means.
  • the cooling system implements a method of early opening of the controlled thermostat when it is cold.
  • the control unit comprises means for receiving the temperature of the fluid Tf, means for calculating a difference between the temperature of the fluid Tf and the setpoint temperature Tcons, means for storing a first predetermined temperature difference threshold S1.
  • the control unit comprises means for estimating a temperature difference dT between the respective fluids of the heat exchange and main circuits above a temperature difference threshold between respective fluids as a function of at at least one driving condition or at least one external climatic condition identified by detection means.
  • the control unit finally comprises means for establishing a corrective command Ccor for opening the thermostat, and, possibly, means for deactivating the corrective command Ccor.
  • the control unit may include means for determining an opening percentage of the controlled thermostat for the regulation command Creg and for the corrective command Ccor.
  • the control unit comprises means for selecting the highest opening percentage by taking it as the final opening percentage of a final command Cfin to open the controlled thermostat.

Description

Domaine technique de l'inventionTechnical field of the invention

La présente invention concerne un procédé d'ouverture anticipée d'un thermostat froid dans un système de refroidissement d'un moteur thermique, avantageusement d'un véhicule automobile. La présente invention concerne aussi un système de refroidissement pour la mise en oeuvre d'un tel procédé d'ouverture, avantageusement dans un véhicule automobile.The present invention relates to a method for early opening of a cold thermostat in a cooling system of a heat engine, advantageously of a motor vehicle. The present invention also relates to a cooling system for the implementation of such an opening method, advantageously in a motor vehicle.

Art antérieurPrior art

De manière schématique et simplifiée, un système de refroidissement d'un moteur thermique comprend un circuit principal de refroidissement pour une circulation d'un fluide de refroidissement muni d'au moins un capteur de température du fluide, le circuit principal de refroidissement traversant le moteur thermique et lui prélevant de la chaleur.Schematically and simplified, a heat engine cooling system comprises a main cooling circuit for circulation of a cooling fluid provided with at least one fluid temperature sensor, the main cooling circuit passing through the engine heat and drawing heat from it.

Le système de refroidissement comprend aussi un circuit d'échange thermique pour le refroidissement du fluide, ce circuit d'échange thermique comprenant au moins un ou des radiateurs.The cooling system also comprises a heat exchange circuit for cooling the fluid, this heat exchange circuit comprising at least one or more radiators.

Un thermostat piloté par une unité de contrôle, faisant partie du système de refroidissement, opère une fermeture et une ouverture au moins partielle du circuit d'échange thermique. L'unité de contrôle présente des moyens de commande pilotant le thermostat selon une commande de régulation en fonction d'au moins une première température prédéterminée de consigne sauvegardée dans des moyens de mémorisation. Il peut y avoir deux températures de consigne avec une température basse et une température haute de consigne.A thermostat controlled by a control unit, forming part of the cooling system, operates a closing and an at least partial opening of the heat exchange circuit. The control unit has control means controlling the thermostat according to a regulation command as a function of at least one first predetermined set point temperature saved in memory means. There can be two setpoint temperatures with a low temperature and a high temperature setpoint.

Par thermostat froid, dans le cadre de la présente invention, il est entendu un thermostat qui présente deux températures très différentes entre la température du fluide de refroidissement dans le circuit principal et la température du fluide de refroidissement dans le circuit d'échange thermique.By cold thermostat, in the context of the present invention, it is understood a thermostat which has two very different temperatures between the temperature of the cooling fluid in the main circuit and the temperature of the coolant in the heat exchange circuit.

Un thermostat est un système mécanique qui s'ouvre à partir d'une certaine température de fluide de refroidissement et laisse passer le fluide vers le radiateur du circuit d'échange thermique pour être refroidi.A thermostat is a mechanical system which opens from a certain temperature of the cooling fluid and lets the fluid pass towards the radiator of the heat exchange circuit to be cooled.

Un thermostat piloté est un système thermomécanique, qui permet de contrôler la température d'ouverture du circuit d'échange thermique ou circuit du ou des radiateurs. On peut ainsi réguler la température de fluide de refroidissement.A controlled thermostat is a thermomechanical system, which makes it possible to control the opening temperature of the heat exchange circuit or circuit of the radiator(s). It is thus possible to regulate the temperature of the cooling fluid.

En pratique, on définit au moins deux valeurs de consigne parmi lesquelles une consigne de régulation haute et une consigne de régulation basse pour trouver le meilleur compromis entre, d'une part, la réduction des frottements et la réduction de la dilution de carburant dans l'huile, ce qui correspond à la consigne de régulation haute et, d'autre part, la tenue thermomécanique du moteur, ce qui correspond à la consigne de régulation basse.In practice, at least two setpoint values are defined, among which a high regulation setpoint and a low regulation setpoint to find the best compromise between, on the one hand, the reduction of friction and the reduction of fuel dilution in the oil, which corresponds to the high regulation setpoint and, on the other hand, the thermomechanical behavior of the engine, which corresponds to the low regulation setpoint.

Le thermostat est constitué d'une cartouche de cire. La cire, en se dilatant permet d'ouvrir la section de passage du fluide de refroidissement. Le pilotage du thermostat consiste à chauffer la cire, pour décaler le point d'ouverture vers une température plus basse.The thermostat consists of a wax cartridge. As the wax expands, it opens up the cooling fluid passage section. Controlling the thermostat consists of heating the wax, to shift the opening point to a lower temperature.

Une unité de contrôle du système de refroidissement calcule, en fonction de la consigne à atteindre et de plusieurs autres informations, une précommande, une commande proportionnelle, et une commande intégrale. La somme de ces trois commandes définit la commande à appliquer au thermostat pour respecter la consigne, aussi appelée commande de régulation.A cooling system control unit calculates, based on the setpoint to be reached and several other pieces of information, a pre-control, a proportional control, and an integral control. The sum of these three commands defines the command to be applied to the thermostat to respect the setpoint, also called regulation command.

Les paramètres du pilotage du thermostat par l'unité de contrôle sont optimisés pour assurer le meilleur suivi de consigne, en régime stabilisé.The parameters for controlling the thermostat by the control unit are optimized to ensure the best follow-up of the set point, in steady state.

Lorsque le système de régulation va piloter le thermostat pour sa première ouverture après un démarrage consécutif à un arrêt relativement long, par exemple supérieur à 45 minutes, les deux côtés du thermostat correspondant respectivement au circuit principal et au circuit d'échange thermique sont à des températures très différentes.When the regulation system is going to control the thermostat for its first opening after a start-up following a relatively long shutdown, for example greater than 45 minutes, the two sides of the thermostat corresponding respectively to the main circuit and to the heat exchange circuit are at very different temperatures.

Le côté dirigé vers le moteur thermique donc vers le circuit principal est en contact avec un fluide chaud tandis que le côté dirigé vers le radiateur et le circuit d'échange thermique est en en contact avec un fluide froid, car le fluide n'a pas encore circulé à travers le radiateur et le moteur et n'a pas été alimenté en fluide chaud en provenance du circuit principal.The side directed towards the heat engine and therefore towards the main circuit is in contact with a hot fluid while the side directed towards the radiator and the heat exchange circuit is in contact with a cold fluid, because the fluid has no still circulated through the radiator and the engine and was not supplied with hot fluid from the main circuit.

Cette différence de température va faire que le thermostat alors qualifié de froid va s'ouvrir plus lentement, car le système de régulation est réglé pour un régime stabilisé, où le fluide dans la partie du tuyau radiateur est relativement chaud.This temperature difference will cause the thermostat then qualified as cold to open more slowly, because the regulation system is set for a stabilized regime, where the fluid in the part of the radiator pipe is relatively hot.

Il va être observé un dépassement positif de température de fluide par rapport à la consigne, suivi d'un dépassement négatif en retour. Le dépassement positif peut conduire à l'activation du ventilateur de refroidissement, ce qui est préjudiciable en termes de consommation.A positive overshoot of the fluid temperature with respect to the setpoint will be observed, followed by a negative overshoot in return. The positive overshoot can lead to the activation of the cooling fan, which is detrimental in terms of consumption.

Le document CN-A-107893697 décrit un procédé de commande d'un thermostat électronique d'un système de refroidissement à circulation de fluide d'un moteur de véhicule automobile. Le procédé prévoit le suivi d'une température de consigne de fluide. La température de consigne de fluide est corrigée par un coefficient de correction fonction de la vitesse du véhicule, de la démultiplication sélectionnée.The document CN-A-107893697 describes a method for controlling an electronic thermostat of a fluid circulation cooling system of a motor vehicle engine. The method provides for the monitoring of a fluid setpoint temperature. The fluid setpoint temperature is corrected by a correction coefficient depending on the speed of the vehicle, on the gear ratio selected.

Une différence de température entre la température en vigueur et la température de consigne ainsi corrigée est suivie et l'ouverture du thermostat est régulée en fonction de la différence. La divulgation de ce document n'est cependant pas relative à une grande différence de température existant entre le fluide du circuit principal du système passant par le moteur thermique et le fluide du circuit d'échange thermique pour le refroidissement du fluide, cette différence affectant le fonctionnement du thermostat et son efficacité.A temperature difference between the current temperature and the set temperature thus corrected is monitored and the opening of the thermostat is regulated according to the difference. The disclosure of this document does not, however, relate to a large temperature difference existing between the fluid of the main circuit of the system passing through the heat engine and the fluid of the heat exchange circuit for cooling the fluid, this difference affecting the thermostat operation and efficiency.

On connaît encore le document US8201524B2 correspondant au préambule de la revendication 1.We still know the document US8201524B2 corresponding to the preamble of claim 1.

Par conséquent, le problème à la base de la présente invention, est, dans un système de refroidissement par fluide d'un moteur thermique avec un thermostat piloté pour l'ouverture d'un circuit d'échange thermique du fluide encore froid à partir d'un circuit principal passant par le moteur déjà chaud, de corriger la commande de régulation selon l'état de la technique en tenant compte de la différence de température entre le fluide du circuit principal et le fluide du circuit d'échange thermique non encore suffisamment chaud.Therefore, the problem at the base of the present invention is, in a fluid cooling system of a heat engine with a controlled thermostat for the opening of a heat exchange circuit of the still cold fluid from 'a circuit main passing through the engine which is already hot, to correct the regulation control according to the state of the art by taking into account the temperature difference between the fluid of the main circuit and the fluid of the heat exchange circuit which is not yet sufficiently hot.

Résumé de l'inventionSummary of the invention

A cet effet, la présente invention concerne un procédé d'ouverture anticipée d'un thermostat piloté froid dans un système de refroidissement par fluide caloporteur d'un moteur thermique, le thermostat piloté opérant une fermeture et une ouverture au moins partielle d'un circuit d'échange thermique par rapport à un circuit principal de refroidissement du système, le thermostat étant commandé par une commande de régulation d'ouverture à partir d'une température en vigueur du fluide et une température de consigne, une commande corrective d'ouverture du thermostat étant établie quand un premier écart entre la température en vigueur de fluide et la température de consigne est inférieure de moins d'un premier seuil d'écart de température prédéterminé et quand au moins une condition de fonctionnement du moteur ou au moins une condition climatique extérieure a été reconnue par expérience comme entraînant une différence de température entre les fluides respectifs des circuits d'échange thermique et principal au-dessus d'un seuil d'écart de température entre fluides respectifs, caractérisé en ce qu'à un instant donné, une commande finale d'ouverture du thermostat est établie après comparaison de la commande de régulation d'ouverture et de la commande corrective d'ouverture, avec un pourcentage d'ouverture final du thermostat, la commande finale d'ouverture du thermostat piloté étant celle des deux commandes activant seule l'ouverture du thermostat ou celle activant l'ouverture du thermostat avec le plus grand pourcentage d'ouverture devenant le pourcentage d'ouverture final du thermostat quand les deux commandes activent l'ouverture du thermostat.To this end, the present invention relates to a method for early opening of a cold controlled thermostat in a heat transfer fluid cooling system of a heat engine, the controlled thermostat effecting at least partial closing and opening of a circuit of heat exchange with respect to a main cooling circuit of the system, the thermostat being controlled by an opening regulation command based on a current temperature of the fluid and a setpoint temperature, a corrective command for opening the thermostat being established when a first difference between the fluid temperature in effect and the setpoint temperature is lower by less than a first predetermined temperature difference threshold and when at least one engine operating condition or at least one climatic condition has been recognized by experience as causing a temperature difference between the respective fluids of the heat exchange circuits. e and main above a temperature difference threshold between respective fluids, characterized in that at a given instant, a final thermostat opening command is established after comparison of the opening regulation command and of the corrective opening command, with a final opening percentage of the thermostat, the final opening command of the controlled thermostat being that of the two commands activating only the opening of the thermostat or that activating the opening of the thermostat with the most large percentage open becoming the final percentage open of the thermostat when both commands activate the opening of the thermostat.

La présente invention prévoit de mettre en oeuvre une commande corrective d'ouverture du thermostat afin que la température du fluide en vigueur ne dépasse pas la température de consigne puis retombe en dessous de la température de consigne, le dépassement de la température de consigne pouvant entraîner une activation du ventilateur du système de refroidissement, ce qui est préjudiciable en terme de consommation.The present invention provides for the implementation of a corrective thermostat opening control so that the temperature of the fluid in force does not exceed the setpoint temperature and then falls below the setpoint temperature, exceeding the setpoint temperature possibly causing an activation of cooling system fan, which is detrimental in terms of consumption.

Ceci se produit quand la différence de température de fluide des deux côtés du thermostat est importante et que la température de fluide s'approche de la température de consigne. Il est alors appliqué une commande corrective prédéterminée au thermostat. L'écart est avantageusement prédéterminé pour que le thermostat soit commandé avant que le système de régulation par une commande de régulation ne commande lui-même l'ouverture du thermostat.This occurs when the fluid temperature difference on both sides of the thermostat is large and the fluid temperature approaches the setpoint temperature. A predetermined corrective command is then applied to the thermostat. The difference is advantageously predetermined so that the thermostat is controlled before the regulation system by a regulation command itself controls the opening of the thermostat.

Comme une différence de température entre les fluides respectifs des circuits d'échange thermique et principal au-dessus d'un seuil d'écart de température entre fluides respectifs n'est pas directement mesurable , il a été choisi de surveiller au moins une condition de fonctionnement du moteur ou au moins une condition climatique extérieure qui est expérimentalement connue pour entraîner une différence de température entre les fluides respectifs des circuits d'échange thermique et principal au-dessus d'un seuil d'écart de température entre fluides respectifs.As a temperature difference between the respective fluids of the heat exchange and main circuits above a temperature difference threshold between respective fluids is not directly measurable, it was chosen to monitor at least one condition of operation of the engine or at least one external climatic condition which is experimentally known to cause a temperature difference between the respective fluids of the heat exchange and main circuits above a temperature difference threshold between respective fluids.

Si la commande de régulation propose un pourcentage d'ouverture plus élevé que la commande corrective, il est conservé une régulation de consigne. Inversement, si la commande de régulation propose un pourcentage d'ouverture moins élevé que la commande corrective, la régulation de consigne, n'étant alors pas active ou peu active, peut être remplacée par la commande corrective avec son pourcentage d'ouverture spécifique. Le cas le plus fréquent est cependant que la commande corrective anticipe complètement la commande de régulation qui n'aurait pas alors déclenché prise isolément une ouverture du thermostat piloté.If the regulation command proposes a higher opening percentage than the corrective command, a setpoint regulation is maintained. Conversely, if the regulation command proposes a lower opening percentage than the corrective command, the setpoint regulation, then not being active or not very active, can be replaced by the corrective command with its specific opening percentage. The most frequent case is however that the corrective command completely anticipates the regulation command which would not then have triggered, taken in isolation, an opening of the controlled thermostat.

Avantageusement, le moteur thermique est un moteur de véhicule automobile, ladite au moins une condition de fonctionnement du moteur thermique étant une condition de roulage du véhicule automobile.Advantageously, the heat engine is a motor vehicle engine, said at least one operating condition of the heat engine being a driving condition of the motor vehicle.

Avantageusement, ladite au moins une condition de roulage est sélectionnée unitairement ou en combinaison parmi les conditions de roulage suivantes : une première ouverture du thermostat après un démarrage moteur froid consécutif à un arrêt d'au moins 45 minutes, une vitesse de plus de 80Km/H de roulage avec thermostat fermé pendant une durée de plus de trente minutes ou ladite au moins une condition climatique est sélectionnée unitairement ou en combinaison parmi les conditions climatiques suivantes : une température extérieure de moins de 5°C, un temps pluvieux ou venteux.Advantageously, said at least one driving condition is selected individually or in combination from the following driving conditions: a first opening of the thermostat after a cold engine start following a stoppage of at least 45 minutes, a speed of more than 80 km/ H of driving with the thermostat closed for a period of more than thirty minutes or said at least one climatic condition is selected individually or in combination from the following climatic conditions: an outside temperature of less than 5°C, rainy or windy weather.

Lors d'un démarrage avec un moteur ayant eu le temps de refroidir, la température de fluide dans le circuit principal va monter rapidement tandis que la température de fluide dans le circuit d'échange thermique reste froide, surtout si la température extérieure est basse et si le circuit d'échange thermique est fortement ventilé ou tout au moins ne récupère pas des calories.When starting with an engine that has had time to cool down, the temperature of the fluid in the main circuit will rise rapidly while the temperature of the fluid in the heat exchange circuit remains cold, especially if the outside temperature is low and if the heat exchange circuit is highly ventilated or at least does not recover calories.

Avantageusement, le pourcentage d'ouverture final est corrigé en baisse en fonction de la température du fluide en donnant un pourcentage d'ouverture final corrigé étant de plus en plus faible plus la température du fluide augmente.Advantageously, the final opening percentage is corrected downwards as a function of the temperature of the fluid, giving a corrected final opening percentage which is lower and lower the higher the temperature of the fluid increases.

Le pourcentage d'ouverture limité sert à protéger le moyen d'ouverture du circuit d'échange thermique du fluide qui est fréquemment un thermostat piloté. il peut exister une fonction de protection du thermostat piloté pour laquelle on va limiter le pilotage du thermostat en fonction de la température du fluide. Cette fonction ne vise pas à éviter une ouverture trop brusque, le temps de réponse du thermostat est de 10 à 20 secondes mais à assurer la durabilité du thermostat. Pour éviter une ouverture trop brusque du thermostat, on va agir sur les réglages du régulateur, et surtout sur la conception du thermostat, pour qu'il s'ouvre progressivement.The limited opening percentage is used to protect the opening means of the fluid heat exchange circuit, which is frequently a controlled thermostat. there may be a protection function of the controlled thermostat for which the control of the thermostat will be limited according to the temperature of the fluid. This function is not intended to avoid too sudden opening, the response time of the thermostat is 10 to 20 seconds, but to ensure the durability of the thermostat. To avoid too sudden opening of the thermostat, we will act on the regulator settings, and especially on the design of the thermostat, so that it opens gradually.

Avantageusement, au moins une condition de désactivation est établie pour arrêter l'activation de la commande corrective d'ouverture.Advantageously, at least one deactivation condition is established to stop the activation of the corrective opening command.

Avantageusement, un gradient de température de fluide étant défini à un instant donné, un seuil de gradient étant prédéterminé correspondant à une ouverture du thermostat, une durée maximale de la commande corrective étant prédéterminée, un deuxième seuil d'écart de température étant prédéterminé en étant inférieur au premier seuil d'écart de température et un troisième seuil d'écart de température étant prédéterminé en étant supérieur au premier seuil d'écart de température, ladite au moins une condition de désactivation est sélectionnée parmi les conditions suivantes prises unitairement ou en combinaison : le gradient de température égal ou inférieur au seuil de gradient, une durée d'application de la commande corrective supérieure à la durée maximale, l'écart de température en vigueur de fluide avec la température de consigne de fluide inférieur au deuxième seuil ou supérieur au troisième seuil.Advantageously, a fluid temperature gradient being defined at a given instant, a gradient threshold being predetermined corresponding to an opening of the thermostat, a maximum duration of the corrective command being predetermined, a second temperature difference threshold being predetermined by being lower than the first temperature difference threshold and a third temperature difference threshold being predetermined by being greater than the first temperature difference threshold, said at least one deactivation condition is selected from among the following conditions taken individually or in combination : the temperature gradient equal to or less than the gradient threshold, a duration of application of the corrective command greater than the maximum duration, the difference in fluid temperature in force with the fluid setpoint temperature less than the second threshold or greater than the third threshold.

Lorsque l'écart de température de fluide est inférieure ou égale au premier seuil, par exemple -10°C, cela se produit si la consigne de température de fluide augmente.When the fluid temperature difference is less than or equal to the first threshold, for example -10° C., this occurs if the fluid temperature setpoint increases.

Lorsque l'écart de température de fluide est supérieure ou égal au deuxième seuil, par exemple 5°C, cela se produit si la consigne de température de fluide diminue, ou si le gradient de température de fluide est important en étant supérieur par exemple à 0,5°C/s.When the fluid temperature difference is greater than or equal to the second threshold, for example 5°C, this occurs if the fluid temperature set point decreases, or if the fluid temperature gradient is high, being greater for example than 0.5°C/s.

Avantageusement, la commande de régulation est établie en étant la somme d'une pré-commande, d'une commande intégrale et d'une commande proportionnelle.Advantageously, the regulation command is established by being the sum of a pre-command, an integral command and a proportional command.

L'invention concerne un système de refroidissement d'un moteur thermique d'un véhicule automobile comprenant un circuit principal de refroidissement pour une circulation d'un fluide de refroidissement muni d'au moins un capteur de température du fluide et un circuit d'échange thermique pour le refroidissement du fluide, un thermostat piloté opérant une fermeture et une ouverture au moins partielle du circuit d'échange thermique, une unité de contrôle présentant des moyens de commande pilotant le thermostat selon une commande de régulation en fonction d'au moins une température prédéterminée de consigne sauvegardée dans des moyens de mémorisation, le système mettant en oeuvre un tel procédé, l'unité de contrôle comprenant des moyens de réception de la température du fluide, des moyens de calcul d'un écart de la température du fluide avec la température de consigne, des moyens de mémorisation d'un premier seuil d'écart de température prédéterminé, des moyens d'estimation d'une différence de température entre les fluides respectifs des circuits d'échange thermique et principal au-dessus d'un seuil d'écart de température entre fluides respectifs en fonction d'au moins une condition de roulage ou d'au moins une condition climatique extérieure identifiée par des moyens de détection, des moyens d'établissement d'une commande corrective d'ouverture du thermostat, caractérisé en ce que l'unité de contrôle comprend des moyens de détermination d'un pourcentage d'ouverture du thermostat piloté pour la commande de régulation et pour la commande corrective et des moyens de sélection du plus haut pourcentage d'ouverture comme pourcentage d'ouverture final d'une commande finale d'ouverture du thermostat piloté.The invention relates to a cooling system for a heat engine of a motor vehicle comprising a main cooling circuit for circulating a cooling fluid provided with at least one fluid temperature sensor and an exchange circuit heat for cooling the fluid, a controlled thermostat effecting at least partial closing and opening of the heat exchange circuit, a control unit having control means controlling the thermostat according to a regulation command as a function of at least one predetermined setpoint temperature saved in memory means, the system implementing such a method, the control unit comprising means for receiving the temperature of the fluid, means for calculating a difference in the temperature of the fluid with the setpoint temperature, means for storing a first predetermined temperature difference threshold, means for estimating a difference temperature between the respective fluids of the heat exchange and main circuits above a temperature difference threshold between respective fluids as a function of at least one driving condition or at least one external climatic condition identified by detection means, means for establishing a corrective thermostat opening command, characterized in that the control unit comprises means for determining an opening percentage of the controlled thermostat for the regulation command and for the order corrective and means for selecting the highest percentage of opening as the final percentage of opening of a final command to open the controlled thermostat.

Un tel système de refroidissement, notamment par son unité de contrôle, vise à anticiper la commande d'un thermostat froid, par rapport à la fonction de consigne de régulation de température de fluide de refroidissement. L'anticipation d'ouverture se fait sur une condition d'écart entre la température du fluide en vigueur et la température de consigne qui peut alors baisser, mais ceci n'est pas forcément le cas, ainsi qu'une estimation d'un thermostat froid avec deux températures différentes du côté du circuit principal et du circuit d'échange thermique.Such a cooling system, in particular through its control unit, aims to anticipate the control of a cold thermostat, with respect to the cooling fluid temperature regulation setpoint function. The anticipation of opening is done on a condition of difference between the temperature of the fluid in force and the setpoint temperature which can then drop, but this is not necessarily the case, as well as an estimate of a thermostat cold with two different temperatures on the side of the main circuit and the heat exchange circuit.

Il est ainsi obtenu des gains en qualité et en prestation, avec un gain de consommation, car pas d'activation intempestive du ventilateur de refroidissement dans le circuit d'échange thermique. Il est aussi obtenu un gain de durabilité du radiateur du circuit d'échange thermique en limitant les variations de température de fluide.Gains in quality and performance are thus obtained, with a gain in consumption, because no untimely activation of the cooling fan in the heat exchange circuit. A gain in durability of the radiator of the heat exchange circuit is also obtained by limiting variations in fluid temperature.

Brève description des figuresBrief description of figures

D'autres caractéristiques, buts et avantages de la présente invention apparaîtront à la lecture de la description détaillée qui va suivre et au regard des dessins annexés donnés à titre d'exemples non limitatifs et sur lesquels :

  • [Fig. 1] - la figure 1 est une représentation d'un mode de réalisation d'un logigramme du procédé d'ouverture anticipée d'un thermostat piloté froid dans un système de refroidissement par fluide caloporteur d'un moteur thermique selon la présente invention,
  • [Fig. 2] - la figure 2 illustre, en fonction du temps t, une courbe de température de consigne de régulation pour un thermostat dans un système de refroidissement et une courbe de température en vigueur de fluide de refroidissement, une courbe de commande corrective selon l'invention, une courbe de commande de régulation selon l'état de la technique, ceci pour deux cas de figure différents avec mention de trois écarts de température entre température en vigueur de fluide et température de consigne.
Other characteristics, objects and advantages of the present invention will appear on reading the detailed description which follows and with regard to the appended drawings given by way of non-limiting examples and in which:
  • [ Fig. 1 ] - there figure 1 is a representation of an embodiment of a flowchart of the method for early opening of a cold controlled thermostat in a heat transfer fluid cooling system of a heat engine according to the present invention,
  • [ Fig. 2 ] - there figure 2 illustrates, as a function of time t, a control setpoint temperature curve for a thermostat in a cooling system and a current temperature curve of the cooling fluid, a corrective control curve according to the invention, a control curve regulation according to the state of the art, this for two different scenarios with mention of three temperature differences between the fluid temperature in force and the setpoint temperature.

Il est à garder à l'esprit que les figures sont données à titre d'exemples et ne sont pas limitatives de l'invention. Elles constituent des représentations schématiques de principe destinées à faciliter la compréhension de l'invention.It should be borne in mind that the figures are given by way of examples and do not limit the invention. They constitute schematic representations of principle intended to facilitate understanding of the invention.

Dans ce qui va suivre, il est fait référence à toutes les figures prises en combinaison. Quand il est fait référence à une figure spécifique, cette figure est à prendre en combinaison avec l'autre figure pour la reconnaissance des références numériques désignées.In what follows, reference is made to all figures taken in combination. When reference is made to a specific figure, this figure is to be taken in combination with the other figure for the recognition of the designated reference numerals.

Description détaillée de l'inventionDetailed description of the invention

En se référant à toutes les figures et principalement à la figure 1, la présente invention concerne un procédé d'ouverture anticipée d'un thermostat piloté froid dans un système de refroidissement par fluide caloporteur d'un moteur thermique.Referring to all the figures and mainly to the figure 1 , the present invention relates to a method for early opening of a cold controlled thermostat in a heat transfer fluid cooling system of a heat engine.

Le thermostat piloté opère une fermeture et une ouverture au moins partielle d'un circuit d'échange thermique par rapport à un circuit principal de refroidissement du système, par exemple selon divers degrés d'ouverture ou un seul degré d'ouverture complète.The controlled thermostat performs at least partial closing and opening of a heat exchange circuit with respect to a main cooling circuit of the system, for example according to various degrees of opening or a single degree of complete opening.

Un thermostat piloté froid signifie que la température du fluide Tf du circuit d'échange thermique est basse en n'ayant pas eu le temps de chauffer et est voisine de la température en vigueur Tf extérieure et même plus basse tandis que la température du fluide Tf du circuit principal commence à chauffer du fait du fonctionnement du moteur thermique, notamment du roulage d'un véhicule automobile propulsé par le moteur thermique, ce qui fait qu'il existe une grande différence de température référencée dT des deux côtés du thermostat, avantageusement supérieure à 20°C.A cold controlled thermostat means that the temperature of the fluid Tf of the heat exchange circuit is low having not had time to heat up and is close to the temperature in force Tf outside and even lower while the temperature of the fluid Tf of the main circuit begins to heat up due to the operation of the heat engine, in particular the driving of a motor vehicle propelled by the heat engine, which means that there is a large difference in temperature referenced dT on both sides of the thermostat, advantageously greater at 20°C.

Le thermostat est commandé par une commande de régulation Creg d'ouverture à partir d'une température en vigueur Tf du fluide et une température de consigne Tcons. A la figure 1, un module régulateur de température de fluide 1 délivre une pré-commande preC, une commande proportionnelle Cprop et une commande intégrale Cint à partir d'une température de fluide et d'une température de consigne Tcons de régulation.The thermostat is controlled by an opening regulation command Creg from a current temperature Tf of the fluid and a setpoint temperature Tcons. To the figure 1 , a fluid temperature regulator module 1 delivers a pre-command preC, a proportional command Cprop and an integral command Cint from a fluid temperature and a regulation setpoint temperature Tcons.

La pré-commande preC, la commande proportionnelle Cprop et la commande intégrale Cint sont sommées dans un module de sommation 2 pour donner une commande de régulation Creg.The pre-command preC, the proportional command Cprop and the integral command Cint are summed in a summing module 2 to give a regulation command Creg.

Selon l'invention, il est établi une commande corrective Ccor d'ouverture du thermostat, totalement indépendante de la commande de régulation Creg. Ceci est mis en oeuvre, selon une première condition, quand un écart entre la température en vigueur Tf de fluide et la température de consigne Tcons est inférieure à un premier seuil d'écart de température prédéterminé, ce premier seuil étant référencé S1 à la figure 1.According to the invention, a corrective command Ccor for opening the thermostat is established, totally independent of the regulation command Creg. This is implemented, according to a first condition, when a difference between the fluid temperature Tf in force and the setpoint temperature Tcons is less than a first predetermined temperature difference threshold, this first threshold being referenced S1 at the figure 1 .

De plus, cela est mis en oeuvre, selon une deuxième condition, quand au moins une condition de fonctionnement du moteur ou au moins une condition climatique extérieure a été précédemment reconnue par expérience comme entraînant une différence de température dT entre les fluides respectifs des circuits d'échange thermique et principal au-dessus d'un seuil d'écart de température entre fluides respectifs.In addition, this is implemented, according to a second condition, when at least one engine operating condition or at least one external climatic condition has previously been recognized by experience as causing a temperature difference dT between the respective fluids of the circuits d heat and main exchange above a temperature difference threshold between respective fluids.

Pour établir le premier seuil S1 d'écart, il est pris la différence entre la température de consigne Tcons et une température sélectionnée de quelques degrés en dessous de la température de consigne Tcons de régulation, par exemple de 1 à 10°C de moins que la température de consigne Tcons.To establish the first difference threshold S1, the difference is taken between the setpoint temperature Tcons and a temperature selected a few degrees below the regulation setpoint temperature Tcons, for example from 1 to 10°C less than the set temperature Tset.

Cette température sélectionnée peut être choisie pour que le thermostat soit commandé avant que la commande de régulation Creg ne soit effective et ne commande elle-même le thermostat.This selected temperature can be chosen so that the thermostat is controlled before the regulation command Creg is effective and itself controls the thermostat.

A la figure 1, un module d'activation 3 de la commande corrective Ccor effectue une activation de cette commande corrective Ccor à partir d'une température en vigueur Tf de fluide, d'une température de consigne Tcons de régulation, d'un écart de température de fluide égal à la température de fluide que retranche la température de consigne de régulation et d'un écart de température dT entre les deux côtés du thermostat, c'est-à-dire entre la température de fluide dans le circuit principal et la température de fluide dans le circuit d'échange thermique.To the figure 1 , an activation module 3 of the corrective command Ccor performs an activation of this corrective command Ccor from a fluid temperature Tf in effect, from a regulation setpoint temperature Tcons, from a fluid temperature difference equal to the fluid temperature subtracted by the regulation setpoint temperature and a temperature difference dT between the two sides of the thermostat, i.e. between the fluid temperature in the main circuit and the fluid temperature in the heat exchange circuit.

Comme cet écart de température dT entre les deux côtés du thermostat ne peut être facilement mesuré, il est considéré au moins une condition de fonctionnement du moteur ou au moins une condition climatique extérieure reconnue comme pouvant occasionner un écart supérieur à un seuil d'écart de température des deux côtés du thermostat prédéterminé.As this temperature difference dT between the two sides of the thermostat cannot be easily measured, it is considered at least one operating condition of the motor or at least one condition outdoor climate recognized as being able to cause a difference greater than a temperature difference threshold on both sides of the predetermined thermostat.

Le module d'activation 3 de la commande corrective Ccor émet alors une demande d'activation act.The activation module 3 of the corrective command Ccor then sends an activation request act.

Comme précédemment mentionné, sans que cela soit limitatif, le moteur thermique peut être un moteur de véhicule automobile. Dans ce cas, ladite au moins une condition de fonctionnement du moteur thermique peut être une condition de roulage du véhicule automobile.As previously mentioned, without this being limiting, the heat engine can be a motor vehicle engine. In this case, said at least one operating condition of the heat engine can be a driving condition of the motor vehicle.

Sans que cela soit limitatif, la ou les conditions de roulage peuvent être sélectionnées unitairement ou en combinaison parmi les conditions de roulage suivantes : une première ouverture du thermostat après un démarrage moteur froid consécutif à un arrêt d'au moins 45 minutes, ce qui donne le temps au moteur de refroidir presque complètement, une vitesse de plus de 80Km/H de roulage avec thermostat fermé pendant une durée de plus de trente minutes, ce qui peut conduire à un refroidissement prononcé du fluide dans le circuit d'échange thermique et inversement à un réchauffement conséquent du fluide du circuit principal.Without this being limiting, the driving condition(s) can be selected individually or in combination from the following driving conditions: a first opening of the thermostat after a cold engine start following a stoppage of at least 45 minutes, which gives the time for the engine to cool almost completely, a speed of more than 80 km/h driving with the thermostat closed for a period of more than thirty minutes, which can lead to a pronounced cooling of the fluid in the heat exchange circuit and vice versa to a consequent heating of the main circuit fluid.

Sans que cela soit limitatif, la ou les conditions climatiques peuvent être sélectionnées unitairement ou en combinaison parmi les conditions climatiques suivantes : une température extérieure de moins de 5°C, un temps pluvieux ou venteux.Without this being limiting, the climatic condition(s) can be selected individually or in combination from the following climatic conditions: an outside temperature of less than 5° C., rainy or windy weather.

Il est possible d'associer une ou des conditions de roulage avec une ou des conditions climatiques. Par exemple lors d'un démarrage après une durée d'arrêt de 45 minutes par température extérieure inférieure à 5°C, il est très probable que le fluide du circuit d'échange thermique est froid alors que le fluide du circuit principal va chauffer pendant le roulage thermostat fermé.It is possible to associate one or more driving conditions with one or more climatic conditions. For example, when starting after a shutdown period of 45 minutes with an outside temperature below 5°C, it is very likely that the fluid in the heat exchange circuit is cold whereas the fluid in the main circuit will heat up for taxiing thermostat closed.

Toujours en se référant à la figure 1, la demande d'activation act émise par le module d'activation 3 de la commande corrective Ccor est transmise à un module de génération 4 d'une commande corrective Ccor.Still referring to the figure 1 , the activation request act sent by the activation module 3 of the corrective command Ccor is transmitted to a generation module 4 of a corrective command Ccor.

Le module de génération 4 d'une commande corrective Ccor peut recevoir, d'autre part, une demande de désactivation desact en provenance d'un module de désactivation 5 de la commande corrective Ccor.The generation module 4 of a corrective command Ccor can receive, on the other hand, a deactivation request desact originating from a module 5 for deactivation of the corrective command Ccor.

Au moins une condition de désactivation peut être établie pour arrêter l'activation de la commande corrective Ccor d'ouverture.At least one deactivation condition can be established to stop the activation of the corrective opening Ccor command.

Le module de désactivation 5 émet, le cas échéant, une demande de désactivation desact en fonction d'une température de fluide, d'une température de consigne Tcons de régulation, d'une durée de la commande corrective Ccor en comparaison avec une durée prédéterminée maximale de la commande corrective Ccor, d'un gradient de température GT défini à un instant donné, un seuil de gradient étant prédéterminé pour correspondre à une ouverture du thermostat, d'un deuxième écart de température en comparaison avec un deuxième seuil S2 d'écart de température prédéterminé en étant inférieur au premier seuil S1 d'écart de température et d'un troisième écart de température en comparaison avec un troisième seuil S3 d'écart de température prédéterminé en étant supérieur au premier seuil S1 d'écart de température.The deactivation module 5 sends, if necessary, a deactivation request deact according to a fluid temperature, a regulation setpoint temperature Tcons, a duration of the corrective command Ccor in comparison with a predetermined duration maximum of the corrective command Ccor, of a temperature gradient GT defined at a given instant, a gradient threshold being predetermined to correspond to an opening of the thermostat, of a second temperature difference in comparison with a second threshold S2 of predetermined temperature difference being lower than the first temperature difference threshold S1 and a third temperature difference in comparison with a third temperature difference threshold S3 predetermined being greater than the first temperature difference threshold S1.

La ou les conditions de désactivation peuvent être sélectionnées parmi les conditions suivantes prises unitairement ou en combinaison : le gradient de température GT étant égal ou inférieur au seuil de gradient, la durée d'application D de la commande corrective Ccor étant supérieure à la durée maximale prédéterminée de la commande corrective Ccor, l'écart de température en vigueur Tf de fluide avec la température de consigne Tcons de fluide étant inférieur au deuxième seuil S2 ou étant supérieur au troisième seuil S3.The deactivation condition(s) can be selected from the following conditions taken individually or in combination: the temperature gradient GT being equal to or less than the gradient threshold, the duration of application D of the corrective command Ccor being greater than the maximum duration of the corrective command Ccor, the temperature difference in force Tf of the fluid with the setpoint temperature Tcons of the fluid being lower than the second threshold S2 or being higher than the third threshold S3.

Si la ou les conditions de désactivation sont remplies, aucune commande corrective Ccor n'est émise ou cesse d'être émise.If the deactivation condition(s) are met, no Ccor corrective command is issued or ceases to be issued.

Pour ordre d'idée, le seuil de gradient de température GT peut être égal à -0,3°C/s, le gradient de température GT étant égal ou inférieur au seuil de gradient pour une désactivation. La durée d'application D de la commande corrective Ccor peut avoir dépassé une durée prédéterminée maximale de la commande corrective Ccor de 20 secondes pour une désactivation.As an idea, the temperature gradient threshold GT can be equal to −0.3° C./s, the temperature gradient GT being equal to or less than the gradient threshold for a deactivation. The duration of application D of the corrective command Ccor may have exceeded a maximum predetermined duration of the corrective command Ccor of 20 seconds for a deactivation.

Un écart de température en vigueur Tf de fluide avec la température de consigne Tcons de fluide inférieur au deuxième seuil S2, par exemple de -10°C, peut être aussi une condition de désactivation. Cela peut se produire, par exemple, si la température de consigne de fluide augmente.A temperature difference in force Tf of fluid with the setpoint temperature Tcons of fluid lower than the second threshold S2, for example -10° C., can also be a deactivation condition. This can happen, for example, if the fluid setpoint temperature increases.

Un écart de température en vigueur Tf de fluide avec la température de consigne Tcons de fluide supérieur au troisième seuil S3 par exemple de 5°C peut être une autre condition de désactivation. Cela se produit si la température de consigne de fluide diminue ou si le gradient de température GT de fluide est important, en étant par exemple supérieur à 0,5°C/s.A temperature difference in force Tf of fluid with the setpoint temperature Tcons of fluid greater than the third threshold S3 for example by 5° C. can be another deactivation condition. This occurs if the fluid setpoint temperature decreases or if the fluid temperature gradient GT is high, for example being greater than 0.5° C./s.

Il est possible de faire varier les seuils d'activation ou de désactivation de la commande corrective Ccor en fonction de la température de consigne Tcons.It is possible to vary the activation or deactivation thresholds of the corrective command Ccor according to the setpoint temperature Tcons.

Quand aucune demande de désactivation desact émise par le module de désactivation 5 ne parvient au module de génération 4 d'une commande corrective Ccor, le module de génération 4 émet une commande corrective Ccor en direction d'un module de comparaison 6 recevant aussi une commande de régulation Creg de la part du module de sommation 2.When no deactivation request desact sent by the deactivation module 5 reaches the generation module 4 of a corrective command Ccor, the generation module 4 sends a corrective command Ccor to a comparison module 6 also receiving a command regulation Creg from the summing module 2.

On définit des écarts de température entre la température en vigueur Tf de fluide et la température de consigne Tcons en soustrayant la température de consigne Tcons à la température en vigueur Tf de fluide.Temperature differences between the fluid temperature Tf in effect and the setpoint temperature Tcons are defined by subtracting the setpoint temperature Tcons from the fluid temperature Tf in effect.

Plus l'écart de température de fluide est négatif, plus la température de fluide est en dessous de la température de consigne Tcons tandis que plus l'écart de température de fluide est positif, plus la température de fluide est au-dessus de la température de consigne Tcons.The more the fluid temperature difference is negative, the more the fluid temperature is below the setpoint temperature Tcons while the more the fluid temperature difference is positive, the more the fluid temperature is above the temperature setpoint Tcons.

A un instant donné, une commande finale Cfin d'ouverture du thermostat peut être établie après comparaison de la commande de régulation Creg d'ouverture et de la commande corrective Ccor d'ouverture dans le module de comparaison 6. La commande finale Cfin d'ouverture du thermostat peut intégrer un pourcentage d'ouverture final du thermostat.At a given instant, a final command Cfin for opening the thermostat can be established after comparing the regulation command Creg for opening and the corrective command Ccor for opening in the comparison module 6. The final command Cfin d' opening of the thermostat can integrate a final opening percentage of the thermostat.

Dans le module de comparaison 6, il est pris comme commande finale Cfin d'ouverture du thermostat piloté celle des deux commandes Creg, Ccor entre commande de régulation Creg et commande corrective Ccor activant seule l'ouverture du thermostat.In the comparison module 6, it is taken as final command Cfin to open the controlled thermostat that of the two commands Creg, Ccor between regulation command Creg and corrective command Ccor activating only the opening of the thermostat.

Quand la commande de régulation Creg et la commande corrective Ccor activent simultanément le thermostat, la commande finale Cfin d'ouverture du thermostat piloté est celle activant l'ouverture du thermostat avec le plus grand pourcentage d'ouverture.When the regulation command Creg and the corrective command Ccor simultaneously activate the thermostat, the final command Cfin opening of the controlled thermostat is the one activating the opening of the thermostat with the greatest percentage of opening.

Le plus grand pourcentage d'ouverture entre les deux commandes Creg, Ccor de régulation et corrective devient alors le pourcentage d'ouverture final du thermostat.The greatest percentage of opening between the two commands Creg, Ccor of regulation and corrective then becomes the final percentage of opening of the thermostat.

La figure 2 montre quatre cas de figure de mise en oeuvre du procédé de régulation selon un mode de réalisation de la présente invention, les cas de figure étant montrés superposés deux à deux à cette figure 2. Le premier cas de figure est en partie haute à gauche de la figure 2, le deuxième cas de figure étant en partie haute à droite de la figure 2 tandis que le troisième cas de figure est en partie inférieure à gauche de la figure 2 et le quatrième cas de figure est en partie inférieure à droite de la figure 2.There figure 2 shows four scenarios of implementation of the regulation method according to an embodiment of the present invention, the scenarios being shown superimposed two by two on this figure 2 . The first scenario is in the upper left part of the figure 2 , the second scenario being in the upper part to the right of the figure 2 while the third scenario is in the lower left part of the figure 2 and the fourth scenario is in the lower right part of the figure 2 .

Pour chaque cas de figure, il est montré en fonction du temps t quatre courbes relatives respectivement à la température de consigne Tcons pour le fluide du système de refroidissement, la température en vigueur Tf du fluide, à la commande de régulation Creg effectuée selon l'état de la technique et à la commande de correction que met en oeuvre le procédé selon la présente invention.For each case, there are shown as a function of time t four curves relating respectively to the setpoint temperature Tcons for the cooling system fluid, the current temperature Tf of the fluid, to the regulation command Creg carried out according to the state of the art and to the correction control implemented by the method according to the present invention.

Les valeurs S1, S2 et S3 sont respectivement les premier, deuxième et troisième seuils précédemment mentionnés, le deuxième seuil S2 d'écart de température étant inférieur au premier seuil S1 d'écart de température et le troisième seuil S3 d'écart de température étant supérieur au premier seuil S1 d'écart de température.The values S1, S2 and S3 are respectively the first, second and third thresholds previously mentioned, the second temperature difference threshold S2 being lower than the first temperature difference threshold S1 and the third temperature difference threshold S3 being greater than the first temperature difference threshold S1.

Quand la température en vigueur Tf du fluide se rapproche de la température de consigne Tcons avec un écart inférieur au premier seuil S1, la commande corrective Ccor permet une ouverture du thermostat alors que la commande de régulation Creg ne le permettait pas.When the temperature in force Tf of the fluid approaches the setpoint temperature Tcons with a difference less than the first threshold S1, the corrective command Ccor allows opening of the thermostat whereas the regulation command Creg did not allow it.

Il s'ensuit que la température en vigueur Tf de fluide ne va pas dépasser la température de consigne Tcons et par exemple ne pas osciller en dépassement et en baisse autour de cette température de consigne Tcons comme quand une ouverture du thermostat est effectuée par la commande de régulation Creg comme le prévoyait l'état de la technique.It follows that the temperature in force Tf of the fluid will not exceed the setpoint temperature Tcons and for example will not oscillate in overshoot and fall around this setpoint temperature Tcons as when the thermostat is opened by the control regulation Creg as foreseen by the state of the art.

En prenant le premier cas de figure illustré en partie haute à gauche de la figure 2, après mise en oeuvre de la commande corrective Ccor sans commande de régulation Creg, la température en vigueur Tf du fluide n'atteint pas la température de consigne Tcons et la commande corrective Ccor est arrêtée. Après arrêt de la commande corrective Ccor, la température en vigueur Tf du fluide commence à remonter sans que son écart avec la température de consigne Tcons ne dépasse le premier seuil S1. La flèche verticale orientée vers le bas indique une baisse de température.Taking the first scenario illustrated in the upper left part of the figure 2 , after implementation of the corrective command Ccor without regulation command Creg, the temperature in force Tf of the fluid does not reach the setpoint temperature Tcons and the corrective command Ccor is stopped. After stopping the corrective command Ccor, the temperature in force Tf of the fluid begins to rise without its difference with the setpoint temperature Tcons exceeding the first threshold S1. The vertical arrow pointing down indicates a drop in temperature.

En prenant le deuxième cas de figure illustré en partie haute à droite de la figure 2, après mise en oeuvre de la commande corrective Ccor sans commande de régulation Creg, la température en vigueur Tf du fluide n'atteint pas la température de consigne Tcons et la commande corrective Ccor est arrêtée du fait de la mise en oeuvre de la commande de régulation Creg la remplaçant.Taking the second scenario illustrated in the upper right part of the figure 2 , after implementation of the corrective command Ccor without regulation command Creg, the temperature in force Tf of the fluid does not reach the setpoint temperature Tcons and the corrective command Ccor is stopped due to the implementation of the control of Creg regulation replacing it.

La baisse de la température de consigne Tcons active la régulation et la commande de régulation Creg en maintenant l'ouverture du thermostat. La commande corrective Ccor a été arrêtée du fait que l'écart de température en vigueur Tf de fluide avec la température de consigne Tcons de fluide est supérieur au troisième seuil S3, ce qui est montré par la flèche du troisième seuil S3 n'atteignant pas la courbe de la température en vigueur Tf de fluide.The drop in the setpoint temperature Tcons activates the regulation and the regulation command Creg while maintaining the opening of the thermostat. The corrective command Ccor has been stopped because the temperature difference in force Tf of the fluid with the setpoint temperature Tcons of the fluid is greater than the third threshold S3, which is shown by the arrow of the third threshold S3 not reaching the curve of the effective temperature Tf of the fluid.

En prenant le troisième cas de figure illustré en partie inférieure à gauche de la figure 2, après mise en oeuvre de la commande corrective Ccor sans commande de régulation Creg, la température en vigueur Tf du fluide n'atteint pas la température de consigne Tcons et la commande corrective Ccor est arrêtée du fait de la mise en oeuvre de la commande de régulation Creg la remplaçant.Taking the third scenario illustrated in the lower left part of the figure 2 , after implementation of the corrective command Ccor without regulation command Creg, the temperature in force Tf of the fluid does not reach the setpoint temperature Tcons and the corrective command Ccor is stopped due to the implementation of the control of Creg regulation replacing it.

Dans ce troisième cas de figure, la température de consigne Tcons est ensuite augmentée sans mise en oeuvre de la commande de régulation Creg, ce qui entraîne l'arrêt de la commande corrective Ccor.In this third case, the setpoint temperature Tcons is then increased without implementing the regulation command Creg, which leads to the stopping of the corrective command Ccor.

En effet, comme l'écart de température en vigueur Tf de fluide avec la nouvelle température de consigne Tcons de fluide est inférieur au deuxième seuil S2, ce qui est montré par la flèche inférieure limitant le deuxième seuil S2 traversant la courbe de la température en vigueur Tf de fluide, la commande corrective Ccor est désactivée.Indeed, as the temperature difference in force Tf of fluid with the new setpoint temperature Tcons of fluid is lower than the second threshold S2, which is shown by the lower arrow limiting the second threshold S2 crossing the curve of the fluid temperature Tf in effect, the corrective command Ccor is deactivated.

En prenant le quatrième cas de figure illustré en partie inférieure à droite de la figure 2, après mise en oeuvre de la commande corrective Ccor sans commande de régulation Creg mais après mise en oeuvre de la commande de régulation Creg pendant la commande corrective Ccor, la température en vigueur Tf du fluide dépasse la température de consigne Tcons restée alors inchangée.By taking the fourth scenario illustrated in the lower right part of the figure 2 , after implementation of the corrective command Ccor without regulation command Creg but after implementation of the regulation command Creg during the corrective command Ccor, the temperature in force Tf of the fluid exceeds the setpoint temperature Tcons then remaining unchanged.

La commande corrective Ccor est arrêtée du fait que l'écart de température en vigueur Tf de fluide avec la température de consigne Tcons de fluide est supérieur au troisième seuil S3, ce qui est montré par la flèche du troisième seuil S3 n'atteignant pas la courbe de la température en vigueur Tf de fluide. La commande de régulation Creg continue cependant à être activée.The corrective command Ccor is stopped because the temperature difference in force Tf of the fluid with the setpoint temperature Tcons of the fluid is greater than the third threshold S3, which is shown by the arrow of the third threshold S3 not reaching the curve of the effective temperature Tf of the fluid. However, the Creg regulation command continues to be activated.

En prenant le quatrième cas de figure illustré en partie inférieure à gauche de la figure 2, comme l'écart de température en vigueur Tf de fluide avec la nouvelle température de consigne Tcons de fluide est inférieur au deuxième seuil S2, ce qui est montré par la flèche inférieure limitant le deuxième seuil S2 traversant la courbe de la température en vigueur Tf de fluide, la commande corrective Ccor est désactivée.Taking the fourth scenario illustrated in the lower left part of the figure 2 , as the temperature difference in force Tf of the fluid with the new setpoint temperature Tcons of the fluid is lower than the second threshold S2, which is shown by the lower arrow limiting the second threshold S2 crossing the curve of the temperature in force Tf of fluid, the Ccor corrective command is deactivated.

La courbe de température en vigueur Tf de fluide qui avait dépassé la température de consigne Tcons redescend vers la température de consigne Tcons en la tangentant sans la dépasser par le bas puis remonte.The current temperature curve Tf of the fluid which had exceeded the setpoint temperature Tcons goes down again towards the setpoint temperature Tcons by tangenting it without exceeding it from below and then goes up again.

Le pourcentage d'ouverture final du thermostat peut être corrigé en baisse en fonction de la température du fluide Tf en donnant un pourcentage d'ouverture final corrigé étant de plus en plus faible plus la température du fluide Tf augmente, ceci pour protéger le thermostat.The final opening percentage of the thermostat can be corrected downwards according to the temperature of the fluid Tf by giving a corrected final opening percentage being lower and lower the higher the temperature of the fluid Tf increases, this to protect the thermostat.

L'invention concerne un système de refroidissement d'un moteur thermique d'un véhicule automobile comprenant un circuit principal de refroidissement pour une circulation d'un fluide de refroidissement muni d'au moins un capteur de température du fluide Tf et un circuit d'échange thermique pour le refroidissement du fluide.The invention relates to a cooling system for a heat engine of a motor vehicle comprising a main cooling circuit for circulation of a cooling fluid provided with at least one fluid temperature sensor Tf and a heat exchange for fluid cooling.

Dans ce système de refroidissement, un thermostat piloté opère une fermeture et une ouverture au moins partielle du circuit d'échange thermique. Une unité de contrôle présente des moyens de commande pilotant le thermostat selon une commande de régulation Creg en fonction d'au moins une température prédéterminée de consigne Tcons sauvegardée dans des moyens de mémorisation.In this cooling system, a controlled thermostat operates at least partial closing and opening of the heat exchange circuit. A control unit has control means controlling the thermostat according to a regulation command Creg as a function of at least one predetermined set point temperature Tcons saved in memory means.

Le système de refroidissement met en oeuvre un procédé d'ouverture anticipée du thermostat piloté quand il est froid. Pour ce faire, l'unité de contrôle comprend des moyens de réception de la température du fluide Tf, des moyens de calcul d'un écart de la température du fluide Tf avec la température de consigne Tcons, des moyens de mémorisation d'un premier seuil S1 d'écart de température prédéterminé.The cooling system implements a method of early opening of the controlled thermostat when it is cold. To do this, the control unit comprises means for receiving the temperature of the fluid Tf, means for calculating a difference between the temperature of the fluid Tf and the setpoint temperature Tcons, means for storing a first predetermined temperature difference threshold S1.

L'unité de contrôle comprend des moyens d'estimation d'une différence de température dT entre les fluides respectifs des circuits d'échange thermique et principal au-dessus d'un seuil d'écart de température entre fluides respectifs en fonction d'au moins une condition de roulage ou d'au moins une condition climatique extérieure identifiée par des moyens de détection. L'unité de contrôle comprend enfin des moyens d'établissement d'une commande corrective Ccor d'ouverture du thermostat, et, éventuellement, des moyens de désactivation de la commande corrective Ccor.The control unit comprises means for estimating a temperature difference dT between the respective fluids of the heat exchange and main circuits above a temperature difference threshold between respective fluids as a function of at at least one driving condition or at least one external climatic condition identified by detection means. The control unit finally comprises means for establishing a corrective command Ccor for opening the thermostat, and, possibly, means for deactivating the corrective command Ccor.

L'unité de contrôle peut comprendre des moyens de détermination d'un pourcentage d'ouverture du thermostat piloté pour la commande de régulation Creg et pour la commande corrective Ccor. Dans ce cas, l'unité de contrôle comprend des moyens de sélection du plus haut pourcentage d'ouverture en le prenant comme pourcentage d'ouverture final d'une commande finale Cfin d'ouverture du thermostat piloté.The control unit may include means for determining an opening percentage of the controlled thermostat for the regulation command Creg and for the corrective command Ccor. In this case, the control unit comprises means for selecting the highest opening percentage by taking it as the final opening percentage of a final command Cfin to open the controlled thermostat.

L'invention n'est nullement limitée aux modes de réalisation décrits et illustrés qui n'ont été donnés qu'à titre d'exemples.The invention is in no way limited to the embodiments described and illustrated which have been given by way of examples only.

Claims (8)

  1. Process for early opening of a cold controlled thermostat in a heat transfer fluid cooling system of a heat engine, the controlled thermostat effecting at least partial closing and opening of a heat exchange circuit with respect to a main cooling circuit of the system, the thermostat being controlled by a regulation command (Creg) for opening from a current temperature (Tf) of the fluid and a set temperature (Tcons), a corrective command (Ccor ) opening of the thermostat being established when a difference between the temperature in force (Tf) of the fluid and the set temperature (Tcons) is less than a first threshold (S1) of predetermined temperature difference and when at least one condition engine operating temperature or at least one external climatic condition has been recognized by experience as causing a temperature difference (dT) between the respective fluids of the heat exchange and main circuits, al above a temperature difference threshold between respective fluids, characterized in that at a given instant, a final command (Cfin) for opening the thermostat is established after comparison of the regulation command (Creg) opening and the corrective opening command (Ccor), with a final opening percentage of the thermostat, the final opening command (Cfin) of the controlled thermostat being that of the two commands (Creg, Ccor) activating only the opening of the thermostat or the one activating the opening of the thermostat with the greatest percentage of opening becoming the final percentage of opening of the thermostat when the two commands (Creg, Ccor) activate the opening of the thermostat.
  2. Method according to the preceding claim, in which the heat engine is a motor vehicle engine, the said at least one operating condition of the heat engine being a driving condition of the motor vehicle.
  3. Method according to the preceding claim, in which the said at least one driving condition is selected individually or in combination from the following driving conditions: a first opening of the thermostat after a cold engine start following a stoppage of at least 45 minutes, a driving speed of more than 80 km/h with the thermostat closed for a period of more than thirty minutes or said at least one climatic condition is selected individually or in combination from the following climatic conditions: an outside temperature of less than 5°C, a rainy or windy weather.
  4. A method according to any preceding claim, in which the final percentage opening is corrected downwards as a function of the temperature of the fluid (Tf) giving a corrected final percentage opening being lower and lower the higher the temperature fluid (Tf) increases.
  5. Method according to any one of the preceding claims, in which at least one deactivation condition is established to stop the activation of the corrective command (Ccor) to open.
  6. Method according to the preceding claim, in which, a fluid temperature gradient (GT) being defined at a given instant, a gradient threshold being predetermined corresponding to an opening of the thermostat, a maximum duration of the corrective command (Ccor) being predetermined , a second temperature difference threshold (S2) being predetermined by being lower than the first temperature difference threshold (S1) and a third temperature difference threshold (S3) being predetermined by being higher than the first threshold (S1 ) of temperature difference, said at least one deactivation condition is selected from the following conditions taken individually or in combination: the temperature gradient (GT) equal to or less than the gradient threshold, an application duration (D) of the corrective command (Ccor) greater than the maximum duration, the temperature difference in force (Tf) of the fluid with the setpoint temperature (Tcons) of the fluid less than the second threshold (S2) or greater than the third threshold (S3).
  7. A method according to any preceding claim, wherein the regulation command (Creg) is established by being the sum of a pre-command (preC), an integral command (Cint) and a proportional command ( Cprop).
  8. Cooling system for a combustion engine of a motor vehicle comprising a main cooling circuit for circulation of a cooling fluid provided with at least one fluid temperature sensor (Tf) and a heat exchange circuit for cooling the fluid, a controlled thermostat operating at least partial closing and opening of the heat exchange circuit, a control unit having control means controlling the thermostat according to a regulation command (Creg) as a function of at least a predetermined setpoint temperature (Tcons) saved in memory means, the system implementing a method according to any one of the preceding claims, the control unit comprising means for receiving the temperature of the fluid (Tf), means for calculating a difference between the temperature of the fluid (Tf) and the setpoint temperature (Tcons), means for storing a first threshold (S1) of difference d e predetermined temperature, means for estimating a temperature difference (dT) between the respective fluids of the heat exchange and main circuits above a temperature difference threshold between respective fluids as a function of at at least one driving condition or at least one external climatic condition identified by detection means, means for establishing a corrective command (Ccor) for opening the thermostat, characterized in that the control unit comprises means for determining an opening percentage of the controlled thermostat for the regulation command (Creg) and for the corrective command (Ccor) and means for selecting the highest opening percentage as the final opening percentage of a final command (Cfin) to open the controlled thermostat.
EP19786378.0A 2018-10-23 2019-09-10 Method for early opening of a cold thermostat in an engine cooling system Active EP3870819B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR1871275A FR3087488B1 (en) 2018-10-23 2018-10-23 PROCESS FOR EARLY OPENING OF A COLD THERMOSTAT IN AN ENGINE COOLING SYSTEM
PCT/FR2019/052086 WO2020084203A1 (en) 2018-10-23 2019-09-10 Method for early opening of a cold thermostat in an engine cooling system

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EP3870819A1 EP3870819A1 (en) 2021-09-01
EP3870819B1 true EP3870819B1 (en) 2023-03-01

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CN115031455A (en) * 2022-04-13 2022-09-09 天津大学 Heat recovery control method and device, electronic equipment and storage medium

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3932277B2 (en) * 2002-10-18 2007-06-20 日本サーモスタット株式会社 Control method of electronic control thermostat
DE10337413A1 (en) * 2003-08-14 2005-03-10 Daimler Chrysler Ag Method of regulating the flow of coolant with a heater shut-off valve
FR2896272B1 (en) * 2006-01-19 2012-08-17 Renault Sas METHOD AND DEVICE FOR CONTROLLING THE FIRST OPENING OF A THERMOSTAT REGULATING THE TEMPERATURE OF AN INTERNAL COMBUSTION ENGINE.
FR2929330B1 (en) * 2008-04-01 2010-04-09 Peugeot Citroen Automobiles Sa ENGINE COOLING CIRCUIT.
DE102009042745A1 (en) * 2009-09-25 2011-03-31 Att Automotivethermotech Gmbh Method for operating cooling and heating circulation system of motor vehicle, involves supercharging and intercooling internal combustion engine by coolants, and supplying coolant from cooling pump to heat exchanger
US10865697B2 (en) * 2014-01-15 2020-12-15 Renault S.A.S. Thermostat device for motor vehicle cooling system, cooling system equipped with such a thermostat device and method of controlling a heating module
FR3016399B1 (en) * 2014-01-15 2016-01-22 Renault Sas METHOD OF ESTIMATING THE OPENING PROPORTION OF A VALVE EQUIPPED WITH A THERMOSTAT AND COOLING SYSTEM OF A DRIVE MOTOR OF A MOTOR VEHICLE COMPRISING A THERMOSTAT
FR3052185B1 (en) * 2016-06-07 2018-06-15 Peugeot Citroen Automobiles Sa METHOD FOR FILLING A COOLING CIRCUIT WITH A COOLANT FLUID
CN107893697B (en) 2017-11-24 2020-04-07 奇瑞汽车股份有限公司 Electronic thermostat opening control method

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WO2020084203A1 (en) 2020-04-30
FR3087488B1 (en) 2020-12-18
FR3087488A1 (en) 2020-04-24
EP3870819A1 (en) 2021-09-01
CN112955637A (en) 2021-06-11
CN112955637B (en) 2024-03-12

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