Process for demisting or defrosting a window

Abstract

The invention relates to a method (100) for demisting or defrosting a glazing unit forming part of a glazing assembly of a motor vehicle, the glazing assembly comprising the glazing unit and a heating system for heating the glazing unit, the method (100) comprising steps of:a - determining a difference (ΔT) between a measured glazing temperature (T1) and a water phase change temperature (T3);b - controlling the heating system (5) as a function of a difference between the determined difference (ΔT) and a safety margin (ΔTc);c - adjusting the safety margin (ΔTc) to a value which depends on environmental parameters of the vehicle; andd - repeating steps a to c. Figure for abstract: Figure 4

Description

Title of the invention: Method for demisting or defrosting a window Field of the invention

[0001] The invention relates to a method for demisting or defrosting a window forming part of a glass assembly of a motor vehicle. State of the art

[0002] When drops of mist appear on the inner face of a window of a motor vehicle, it is known to manually activate the heating, ventilation and air-conditioning (HVAC) system of the vehicle in demisting mode, so as to cause the drops of mist to evaporate.

[0003] However, this method can distract the driver of the vehicle. In addition, manual activation of the HVAC system is only carried out when the drops of mist have already appeared on the glazing and have already degraded the driver's visual perception through the glazing.

[0004] There are vehicles in which the HVAC system is controlled automatically. In this case, the HVAC system comprises a temperature sensor placed on an internal surface of the glazing and a humidity sensor placed inside the passenger compartment. From the measured temperature and humidity, a control module is capable of determining whether a fogging condition exists and consequently activating the HVAC system in defogging mode.

[0005] Document US 2006 / 0004494 A1 describes for example a method for defogging a glazing in which an HVAC system is controlled as a function of a deviation ("FM") between the temperature of the glazing and the dew point temperature. For this purpose, this deviation ("FM") is compared to a dew point margin ("DPM"). If the deviation is greater than the dew point margin plus a pre-defined quantity ("DPM + A"), this means that there is no risk of fogging. If the deviation is between the dew point margin ("DPM") and the dew point margin plus the pre-defined quantity ("DPM + A"), this means that there is a certain risk of fogging and the HVAC system is controlled to operate at a corresponding power between a maximum power (when FM = DPM) and a minimum power (when FM = DPM + A).If the deviation is less than or equal to the dew point margin, it means that there is an imminent risk of fogging or more likely that fogging has already occurred. The glazing temperature is estimated based on the air temperature in the passenger compartment, as well. and possibly the speed of the motor vehicle. The dew point is determined as a function of the temperature and the relative humidity of the air in the passenger compartment of the motor vehicle. The dew point margin is predefined using tests on the motor vehicle. The predefined dew point margin is used to compensate for intrinsic inaccuracies of the humidity sensor. According to this document, in an exemplary embodiment, the inaccuracy of the relative humidity measurement was determined to be 8%, so that the dew point margin ("DPM") was determined to be 2.3°Celsius and was rounded to 3°Celsius.

[0006] In such a method, the value of the dew point margin is fixed in advance, and is not modifiable. The dew point margin must therefore be high enough to avoid fogging in the majority of possible scenarios. Indeed, if the value of the chosen dew point margin is too low, the HVAC system will be inefficient under severe conditions.

[0007] However, the higher the value of the dew point margin chosen, the higher the amount of electrical energy consumed by the HVAC system. Indeed, the higher the dew point margin, the more often the HVAC system is activated and / or is activated at a high power. Summary of the invention

[0008] An aim of the invention is to provide effective demisting or defrosting of the glazing of a motor vehicle, while limiting the quantity of electrical energy consumed.

[0009] This aim is achieved within the framework of the present invention by means of a method for demisting or defrosting a glazing unit forming part of a glazed assembly of a motor vehicle, the glazed assembly comprising the glazing unit and a system for heating the glazing unit, the method comprising steps of: a - determine a difference between a measured glazing temperature and a phase change temperature of the water; b - control the heating system based on a difference between the determined deviation and a safety margin; c - adjust the safety margin to a value that depends on the vehicle's environmental parameters; and d - repeat steps a to c.

[0010] Instead of using a pre-set safety margin, the proposed demisting or defrosting method makes it possible to dynamically adjust the safety margin, depending on the situation, i.e. depending on the environmental parameters of the motor vehicle.

[0011] Adjusting the safety margin allows limiting the amount of energy electricity consumed by the window heating system, since the safety margin is constantly adjusted according to the environmental parameters of the motor vehicle.

[0012] The method may further have the following characteristics:

[0013] According to one embodiment of the method, the phase change temperature of the water is a liquid condensation temperature of the water, and the method comprises a step of: e - determine the liquid condensation temperature of the water as a function of an air temperature measured in a passenger compartment of the motor vehicle and a relative humidity level of the air measured in the passenger compartment of the motor vehicle.

[0014] According to a possible embodiment of the method, the phase change temperature of the water is a solidification temperature of the water.

[0015] According to a possible embodiment of the method, the environmental parameters of the motor vehicle comprise at least one of the following parameters: - air temperature outside the motor vehicle, - a variation in the air temperature outside the motor vehicle over a predefined period of time, - a speed of the motor vehicle, - a variation in the speed of the motor vehicle over a predefined period of time, - a humidity level in the air inside the motor vehicle, - a variation in the humidity level of the air in the passenger compartment of the motor vehicle, over a predefined period of time, - a mode of operation of a ventilation and air conditioning system of the motor vehicle, - instantaneous power available in the vehicle to be consumed by the window heating system.

[0016] According to a possible mode of implementation of the method, the value to which the safety margin is adjusted is determined from a correspondence table which associates predefined values ​​of environmental parameters of the vehicle with precalculated values ​​of safety margins.

[0017] According to a possible mode of implementation of the method, step c comprises a calculation of the safety margin by applying a predefined mathematical function to the environmental parameters.

[0018] According to a possible embodiment of the method, step b comprises controlling the heating system so that the heating system generates thermal power, the generated thermal power being selectively equal to zero or to a predefined non-zero value, depending on the difference between the determined deviation and the safety margin.

[0019] According to a possible embodiment of the method, step b comprises modulating a thermal power generated by the heating system as a function of the difference between the determined deviation and the safety margin.

[0020] According to another aspect, the invention further relates to a control unit for a glazing heating system, configured to execute the steps of the method as defined previously.

[0021] According to another aspect, the invention also relates to a computer program product comprising program code instructions for executing the steps of the method as defined previously, when this program is executed by a computer.

[0022] According to another aspect, the invention also relates to a computer-readable memory storing computer-executable instructions for executing the steps of the method as defined above. Presentation of the drawings

[0023] Other characteristics and advantages will emerge from the following description, which is purely illustrative and non-limiting and must be read in conjunction with the appended figures, among which:

[0024] [Fig-1] - [Fig.l] schematically represents a motor vehicle including a glass unit,

[0025] [Fig.2] - [Fig.2] schematically represents a glazed assembly, in accordance with an embodiment of the invention,

[0026] [Fig.3] - [Fig.3] schematically represents the glazed assembly of [Fig.2], according to a sectional view,

[0027] [Fig.4] - [Fig.4] schematically represents the glazed assembly of [Fig.2], according to an exploded view,

[0028] [Fig.5] - [Fig.5] schematically represents steps of a method for demisting or defrosting a glazing unit forming part of a glazed assembly, in accordance with an embodiment of the invention,

[0029] [Fig.6] - [Fig.6] schematically represents an example of a regulation function which can be implemented to control a heating system for the glazed assembly. Detailed description of an embodiment

[0030] In [Fig.l], the motor vehicle 1 shown comprises a glazed assembly 2. The glazed assembly 2 comprises a glazing unit 3, for example a windshield glazing unit or a rear window glazing unit, which delimits a passenger compartment 4 of the motor vehicle.

[0031] As illustrated in Figures 2 to 4, the glazed assembly 2 comprises the glazing 3, and a heating system 5 for the glazing.

[0032] The term "glazing" designates a structure comprising at least one sheet of organic or mineral glass. The organic glass may consist of a compound comprising acrylates, preferably polymethyl methacrylate (acronym PMMA). The organic glass may also consist of polycarbonate. The glazing may be suitable for installation in a vehicle, in particular a motor vehicle.

[0033] In the example illustrated in Figures 2 to 4, the glazing 3 comprises a first glass sheet 31 and a second glass sheet 32. The first glass sheet 31 comprises a first face 311 intended to be in contact with an interior environment located inside the passenger compartment of the motor vehicle, and a second face 312, opposite the first face 311. The second glass sheet 32 ​​comprises a third face 321, and a fourth face 322, opposite the third face 321 and intended to be in contact with an exterior environment located outside the passenger compartment of the motor vehicle.

[0034] The glazing 3 further comprises one or more interlayer sheet(s) 33 arranged between the first glass sheet 31 and the second glass sheet 32.

[0035] In the example illustrated in Figures 2 to 4, the glazing 3 comprises an interlayer sheet 33 formed from an adhesive material making it possible to secure the glass sheets 31 and 32 together, visually transparent and electrically insulating.

[0036] The interlayer sheet 33 may be made of plastic, for example a viscoelastic polymer, such as polyvinyl butyral (PVB) or an ethylene-vinyl acetate copolymer (EVA). The interlayer sheet is preferably made of standard PVB or acoustic PVB (such as single-layer or tri-layer acoustic PVB). The acoustic PVB may comprise three layers: two outer layers of standard PVB and an inner layer of PVB with added plasticizer so as to make it less rigid than the outer layers.

[0037] The heating system 5 of the glazing comprises a heating sheet 51, a first connection bar 52 and a second connection bar 53, making it possible to electrically connect the heating sheet 51 to an electric current supply source.

[0038] In the example illustrated in Figures 2 to 4, the heating sheet 51 is arranged between the first glass sheet 31 and the interlayer sheet 33.

[0039] In this example, the heating sheet 51 comprises an electrically conductive film 54 covering the second face 312 of the first glass sheet 31.

[0040] The electrically conductive film 54 may be a metallic film, such as a silver-based metallic film for example.

[0041] Each of the first connecting bar 52 and the second connecting bar 53 extends between the first glass sheet 31 and the interlayer sheet 33, and is disposed in contact with the electrically conductive film 54.

[0042] In the example illustrated in Figures 2 to 4, the first connection bar 52 is in the form of a first strip of electrically conductive material extending along a first transverse edge of the glazing 3. The second connection bar 53 is also in the form of a second strip of electrically conductive material extending along a second transverse edge of the glazing 3, opposite the first transverse edge.

[0043] The first connection bar 52 and / or the second connection bar 53 may be formed by printing or screen printing, or by welding a metal strip, before or after application of the electrically conductive film 54, on the first glass sheet 31. The first connection bar 52 and the second connection bar 53 are formed from a material having a low resistance, much lower than the resistance of the material forming the electrically conductive film 54. The first connection bar 52 and the second connection bar 53 may for example be formed from copper.

[0044] The first connecting bar 52 and the second connecting bar 53 function as electrodes. When an electrical supply voltage is applied between the first connecting bar 52 and the second connecting bar 53, an electric current propagates between the two connecting bars in the electrically conductive film 54, which causes heat to be released from the electrically conductive film 54 by Joule effect.

[0045] As illustrated in Figures 2 to 4, the glazed assembly 2 further comprises a first temperature sensor 11, a second temperature sensor 12 and a humidity sensor 13.

[0046] The first temperature sensor 11 is configured to measure a temperature of the glazing 3 (first temperature T1).

[0047] The first temperature sensor 11 may for example comprise a thermistor. The thermistor comprises a block of sensitive material (for example a metal oxide semiconductor material which may be encapsulated between two polymer films). The block of sensitive material has a resistance whose value varies depending on the temperature of the block of sensitive material.

[0048] The block of sensitive material can be arranged between the interlayer sheet 33 and the second glass sheet 32.

[0049] In this way, the block of sensitive material is not in contact with the electrically conductive film 51. Indeed, the interlayer sheet 33 insulates the block of sensitive material from the electrically conductive film 51.

[0050] Alternatively, the block of sensitive material may be arranged inside the interlayer sheet 33. During the manufacture of the glazing 3, the block of sensitive material may first be placed in the stack of sheets, between the second glass sheet 32 ​​and the interlayer sheet 33, so that when the sheets are laminated together, the block of sensitive material is pushed inside the softened material of the interlayer sheet 33 under the effect of the pressure exerted on the stack of sheets.

[0051] The block of sensitive material preferably has a planar shape. The block of sensitive material may, for example, have a width in a range from 0.5 to 3 millimeters (for example 0.5 millimeters), a length in a range from 1 to 6 millimeters (for example 1 millimeter) and a thickness of the order of a few hundred microns (for example 500 micrometers).

[0052] The material of the sensitive material block is chosen to be capable of measuring temperature values ​​in a range going for example from - 50°Celsius up to + 125°Celsius, or at least in a range going from - 40°Celsius up to + 85°Celsius, with a tolerance of up to ±1.0% at 25°Celsius.

[0053] The first temperature sensor 11 is capable of generating a first temperature measurement signal SI representative of the temperature T1 of the glazing 3.

[0054] The second temperature sensor 12 is configured to measure a temperature of the air contained in the passenger compartment of the motor vehicle (second temperature T2).

[0055] The second temperature sensor 12 may comprise a probe fixed to the glazing 3 inside the passenger compartment, for example fixed to the first face 311 of the first sheet of glass 31. The second temperature sensor 12 is arranged to acquire the air temperature at a first point 7 outside the glazing 3.

[0056] The second temperature sensor 12 may be a band gap temperature sensor. Such a sensor comprises a semiconductor material and is configured to determine a temperature of the ambient air from the characterization of a band gap of the semiconductor material.

[0057] The second temperature sensor 12 is capable of generating a second temperature measurement signal S2 representative of the temperature T2 of the air in the passenger compartment of the motor vehicle.

[0058] The humidity sensor 13 is configured to measure a relative humidity level of the air in the passenger compartment of the motor vehicle. The humidity sensor 13 is arranged to acquire a relative humidity level RH of the air at a second point 9 outside the glazing 3.

[0059] The humidity sensor 13 may comprise a probe fixed to the glazing 3, inside the passenger compartment, for example fixed to the first face 311 of the first sheet of glass 31.

[0060] The humidity sensor 13 may be a capacitive type sensor configured to acquire a relative humidity level RH of the air.

[0061] The humidity sensor 13 is capable of generating a third humidity level measurement signal S3 representative of the relative humidity level of the air in the passenger compartment of the motor vehicle.

[0062] As illustrated in Figures 2 and 3, the second temperature sensor 12 and the humidity sensor 13 can be integrated together in the same component. In this way, the temperature T2 and the relative humidity rate RH of the air in the passenger compartment are measured at the same location in the passenger compartment. More precisely, the first point 7 can coincide with the second point 9. By "coincide" is meant that the distance between the first point 7 and the second point 9 is less than 5 mm, preferably less than 2 mm, preferably less than 1 mm.

[0063] The relative humidity rate of the air RH, or hygrometric degree, is the ratio between the partial pressure of the water vapor contained in the air and the saturated vapor pressure at the same temperature. In other words, the relative humidity rate is representative of the ratio between the quantity of water vapor contained in the air and the maximum quantity of water vapor that the air is capable of containing at this temperature. The maximum quantity of water vapor that the air is capable of containing changes with the air temperature. Thus, from the relative humidity rate of the air, and the air temperature, it is possible to determine a dew point temperature, that is to say a liquid condensation temperature of the water.

[0064] The heating system 5 is controlled by a control unit 10. The control unit 10 may be a control unit dedicated to the heating system 5 or be part of the electronic control unit (ECU) of the motor vehicle which is used to control components of the motor vehicle, other than the window heating system.

[0065] The control unit 10 is capable of receiving the first measurement signal S1 from the first temperature sensor 11, the second measurement signal S2 from the second temperature sensor 12 and the third measurement signal S3 from the humidity sensor 13, and of generating a control signal S4 for controlling a supply of electrical current to the heating mat 51, as a function of the first measurement signal S1, the second measurement signal S2 and the third measurement signal S3.

[0066] The heating sheet 51 is supplied with electric current via the connection bars 52 and 53, so as to prevent the appearance of mist or to eliminate mist on the glazing 3, in particular on the first face 311 of the first sheet of glass 31 in contact with the ambient air in the passenger compartment of the motor vehicle.

[0067] For this purpose, the control unit 10 is programmed to execute steps of a ordering process.

[0068] [Fig. 5] schematically represents steps of a control method 100 according to a possible embodiment of the invention.

[0069] According to a first step 101, the control unit 10 determines a phase change temperature of the water T3.

[0070] In this example, the phase change temperature of water T3 is the dew point temperature.

[0071] The control unit 10 determines the dew point temperature as a function of the temperature T2 of the air in the passenger compartment measured by the second temperature sensor 12, and of the relative humidity rate RH of the air in the passenger compartment measured by the humidity sensor 13.

[0072] According to a second step 102, the control unit 10 determines a difference between the temperature T1 of the glazing 3 measured by the first temperature sensor 11 and the phase change temperature of the water T3.

[0073] According to a third step 103, the control unit 10 compares the determined deviation AT with a safety margin ATC.

[0074] According to a fourth step 104, the control unit 10 controls the heating system 5 according to the result of this comparison.

[0075] According to a first possibility, the control unit 10 controls the heating system 5 to selectively activate or deactivate the heating system. For example, if the determined deviation AT is greater than the safety margin ATC, the heating mat 51 of the heating system 5 is not supplied with electric current. In other words, the electric current supplying the heating mat 51 is zero. On the other hand, if the determined deviation AT is less than or equal to the safety margin ATC, the control unit 10 triggers a supply of electric current to the heating mat 51, the electric current having a predefined non-zero value. In this case, the heating system 51 generates a thermal power having a predefined non-zero value.

[0076] According to a second possibility, the control unit 10 controls the heating system 5 to modulate the thermal power generated by the heating system as a function of the determined difference AT.

[0077] For example, the control unit 10 can apply a PID (“proportional, integral, derivative”) regulation function. As illustrated in [Fig. 6], the regulation function receives as input a difference between the determined deviation AT and the safety margin ATC and generates as output a value of the electric current supplying the heating mat 51.

[0078] According to a fifth step 105, the control unit 10 adjusts the ATC safety margin to a value which depends on one or more environmental parameter(s) of the motor vehicle.

[0079] The environmental parameters of the vehicle include at least one of the following parameters: - air temperature outside the motor vehicle, - a variation in the air temperature outside the motor vehicle over a predefined period of time, - a speed of the motor vehicle, - a variation in the speed of the motor vehicle over a predefined period of time, - a humidity level in the air inside the motor vehicle, - a variation in the humidity level of the air in the passenger compartment of the motor vehicle, over a predefined period of time, - a mode of operation of a ventilation and air conditioning system of the motor vehicle, - instantaneous power available in the vehicle to be consumed by the window heating system.

[0080] These environmental parameters can be measured using sensors present in the motor vehicle. Alternatively, these environmental parameters can be calculated by the control unit 10 from other parameters measured using sensors present in the motor vehicle.

[0081] According to a first possibility, the value to which the ATC safety margin is adjusted is determined from a look-up table which associates pre-calculated safety margin values ​​with predefined values ​​of environmental parameters of the vehicle.

[0082] For example, the lookup table may include two pre-calculated safety margin values, namely: a first pre-calculated safety margin value and a second pre-calculated safety margin value, lower than the first pre-calculated safety margin value. If the “air recycling” mode of the ventilation and air conditioning system of the motor vehicle is activated (i.e. the air propelled into the passenger compartment of the motor vehicle by the ventilation and air conditioning system comes from inside the passenger compartment), the ATC safety margin may be set to the first pre-calculated safety margin value. On the other hand, if the “air recycling” mode of the ventilation and air conditioning system of the motor vehicle is deactivated (i.e.the air propelled into the passenger compartment of the motor vehicle by the ventilation and conditioning system comes from outside the passenger compartment), the ATC safety margin can be set to the second precalculated safety margin value.

[0083] According to another example, the correspondence table may comprise a series of pre-calculated safety margin values, each pre-calculated safety margin value being associated with a pre-defined temperature of the air outside the motor vehicle, such that the lower the temperature of the air outside the motor vehicle, the higher the ATC safety margin.

[0084] According to yet another example, the look-up table may comprise a series of pre-calculated safety margin values, each pre-calculated safety margin value being associated with a pre-defined temperature of the air outside the motor vehicle, a pre-defined speed of the motor vehicle and with pre-defined heating powers, generated beforehand by the heating system. The pre-calculated safety margin values ​​may have been obtained from a physical model of the glazing making it possible to estimate a difference between a temperature of the glazing in a viewing zone 14 of the glazing 3 (i.e. an area through which the driver of the vehicle looks) and a temperature of the glazing measured by the first temperature sensor 11 outside the viewing zone 14 of the glazing 3 (for example in an area 13 covered with a visually opaque layer, surrounding the viewing zone 14).

[0085] The physical model of the glazing is for example the combination of a first model making it possible to estimate a temperature of the glazing at a given point of the glazing as a function of the power dissipated by the heating sheet, and of a second model making it possible to determine a map of the distribution of dissipated power which depends on a geometry of the glazing. The physical model thus makes it possible to determine a temperature difference value between two distinct points of the glazing (namely a first point located in the viewing zone of the glazing and a second point located outside the viewing zone of the glazing).

[0086] According to a second possibility, the ATC safety margin is calculated by applying a predefined mathematical function to the environmental parameters.

[0087] For example, the mathematical function may be a function for calculating a value of the ATC safety margin as a function of one or more environmental parameter values. The mathematical function may have been obtained from historical data having been measured on an actual glazing.

[0088] Depending on different environmental parameters, such as the speed of the motor vehicle, or the air renewal rate in the passenger compartment of the motor vehicle, mist may appear on the glazing at different speeds, in particular in the event of sudden acceleration of the motor vehicle, or when the “air recycling” mode is activated.

[0089] The control unit repeats steps 101 to 105, for example with a predefined constant time interval between two successive executions of steps 101 to 105.

[0090] In another exemplary embodiment of the method 100, the change temperature water phase T3 is a solidification temperature of water. In this case, step 101 is not necessary. Indeed, the solidification temperature of water does not depend on the relative humidity rate of the air HR in the passenger compartment. The control unit 10 only performs steps 102 to 105, repeats steps 102 to 105. The method 100 thus makes it possible to prevent the formation of frost on the glazing.

[0091] In yet another embodiment of the method 100, it is implemented with two phase change temperatures: namely with the liquid condensation temperature of the water and with the solidification temperature of the water. The method 100 thus makes it possible to prevent both the formation of fogging and the formation of frost on the glazing. In this case, two separate safety margins are adjusted in parallel by the control unit 10: - a first safety margin which is compared with a first difference between the measured temperature of the glazing and the liquid condensation temperature of the water, and - a second safety margin which is compared with a second difference between the measured glazing temperature and the solidification temperature of the water.

Claims

Claims

1. A method (100) for demisting or defrosting a glazing unit (3) forming part of a glazing assembly (2) of a motor vehicle (1), the glazing assembly (2) comprising the glazing unit (3) and a heating system (5) for heating the glazing unit (3), the method (100) comprising steps of: a - determining a difference (AT) between a measured glazing temperature (T1) and a water phase change temperature (T3); b - controlling the heating system (5) as a function of a difference between the determined difference (AT) and a safety margin (ATC); c - adjusting the safety margin (ATC) to a value which depends on environmental parameters of the vehicle; and d - repeating steps a to c.

2. Method (100) according to claim 1, wherein the phase change temperature of the water (T3) is a liquid condensation temperature of the water, and the method comprises a step of: e - determining the liquid condensation temperature of the water as a function of an air temperature (T2) measured in a passenger compartment of the motor vehicle and a relative humidity level of the air (RH) measured in the passenger compartment of the motor vehicle.

3. The method (100) of claim 1, wherein the phase change temperature of water (T3) is a solidification temperature of water.

4. Method (100) according to one of claims 1 to 3, wherein the environmental parameters of the motor vehicle comprise at least one of the following parameters: - an air temperature outside the motor vehicle, - a variation in the air temperature outside the motor vehicle over a predefined period of time, - a speed of the motor vehicle, - a variation in the speed of the motor vehicle over a predefined period of time, - a humidity level of the air in the passenger compartment of the motor vehicle, - a variation in the humidity level of the air in the passenger compartment of the motor vehicle, over a predefined period of time, - an operating mode of a ventilation and air conditioning system of the motor vehicle, - an instantaneous power available in the vehicle to be consumed by the glazing heating system.

5. Method (100) according to one of claims 1 to 4, in which the value to which the safety margin (ATC) is adjusted is determined from a correspondence table which associates with predefined values ​​of environmental parameters of the vehicle, precalculated values ​​of safety margins.

6. Method (100) according to one of claims 1 to 4, in which step c comprises a calculation of the safety margin (ATC) by applying a predefined mathematical function to the environmental parameters.

7. Method according to one of claims 1 to 6, wherein step b comprises controlling the heating system (5) so that the heating system (5) generates a thermal power, the generated thermal power being selectively equal to zero or to a predefined non-zero value, depending on the difference between the determined deviation (AT) and the safety margin (ATC).

8. Method according to one of claims 1 to 7, in which step b comprises modulating a thermal power generated by the heating system as a function of the difference between the determined deviation (AT) and the safety margin (ATC).

9. Control unit (10) of a heating system (5) of a glazing (3), configured to execute the steps of the method according to one of claims 1 to 8.

10. Computer program product comprising program code instructions for executing the steps of the method according to one of claims 1 to 8, when this program is executed by a computer.

11. A computer-readable memory storing computer-executable instructions for carrying out the steps of the method according to one of claims 1 to 8.

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