CN104406708B - The temperature measurement system and method for electrically heated glass - Google Patents
The temperature measurement system and method for electrically heated glass Download PDFInfo
- Publication number
- CN104406708B CN104406708B CN201410584493.8A CN201410584493A CN104406708B CN 104406708 B CN104406708 B CN 104406708B CN 201410584493 A CN201410584493 A CN 201410584493A CN 104406708 B CN104406708 B CN 104406708B
- Authority
- CN
- China
- Prior art keywords
- temperature
- electric heating
- glass
- heating element
- resistance
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 239000011521 glass Substances 0.000 title claims abstract description 210
- 238000000034 method Methods 0.000 title claims abstract description 28
- 238000009529 body temperature measurement Methods 0.000 title claims abstract description 8
- 238000010438 heat treatment Methods 0.000 claims abstract description 43
- 238000005485 electric heating Methods 0.000 claims description 225
- 239000004576 sand Substances 0.000 claims description 12
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 claims description 7
- 229910052751 metal Inorganic materials 0.000 claims description 7
- 239000002184 metal Substances 0.000 claims description 7
- 229910052709 silver Inorganic materials 0.000 claims description 7
- 239000004332 silver Substances 0.000 claims description 7
- 238000012546 transfer Methods 0.000 claims description 7
- 238000007639 printing Methods 0.000 claims description 5
- 238000005516 engineering process Methods 0.000 abstract description 3
- 238000010257 thawing Methods 0.000 description 45
- 239000004020 conductor Substances 0.000 description 9
- 230000000007 visual effect Effects 0.000 description 6
- 230000000694 effects Effects 0.000 description 4
- 238000002474 experimental method Methods 0.000 description 4
- 238000005259 measurement Methods 0.000 description 4
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 4
- 238000010586 diagram Methods 0.000 description 2
- 230000007613 environmental effect Effects 0.000 description 2
- 239000005357 flat glass Substances 0.000 description 2
- 239000005349 heatable glass Substances 0.000 description 2
- 239000005340 laminated glass Substances 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 230000003287 optical effect Effects 0.000 description 2
- 230000000704 physical effect Effects 0.000 description 2
- 229920006395 saturated elastomer Polymers 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 239000005328 architectural glass Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 239000013256 coordination polymer Substances 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 239000007888 film coating Substances 0.000 description 1
- 238000009501 film coating Methods 0.000 description 1
- 239000012528 membrane Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 239000000523 sample Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Landscapes
- Surface Heating Bodies (AREA)
Abstract
The present invention relates to the defrosting-defogging field of glass product, the more particularly to temperature measurement technology of electrically heated glass, particularly provide a kind of system and method for utilization temperature-coefficient of electrical resistance to measure the temperature of electrically heated glass.The temperature measurement system of the electrically heated glass includes glass plate, electrical heating elements and power supply, and also including current measuring device or electric resistance measuring apparatus, current measuring device or electric resistance measuring apparatus can measure electrical heating elements electric current I after powered up or resistance R；The temperature for being provided with the glass pane surface of electrical heating elements is equal to temperature T of the electrical heating elements.The present invention can avoid temperature sensors multiple in glass surface arrangement, reduce cost；Measured temperature is the overall equivalent temperature of glass, can effectively reflect the bulk temperature distribution of glass；The sight line of glass appearance and in-car or indoor occupant is not affected, when shield glass is applied to, interference is not produced to driver's sight line, is improved the security of running car.
Description
The technical field is as follows:
the invention relates to the field of defrosting and defogging of glass products, in particular to a temperature measurement technology of electric heating glass, and particularly provides a system and a method for measuring the temperature of the electric heating glass by using a resistance temperature coefficient, and also provides an automobile glass system capable of automatically defrosting and defogging and a defogging and defrosting method.
Background art:
in cold weather, the automobile glass and the architectural glass are easy to frost; or when the humidity in the automobile and the indoor is high and the temperature and the external environment are greatly different, the automobile glass and the building glass are easy to fog; therefore, the view lines and the appearances of the inside and the inside of the automobile are influenced, particularly, the front windshield glass of the automobile which provides a good view field for a driver can seriously influence the view line of the driver if frosting and fogging phenomena occur on the front windshield glass, safety accidents are easily caused, and the front windshield glass of the automobile is required to have the functions of defrosting and demisting. With the development of technology, it is known that an electric current is passed through an electric heating element (such as a silver paste printed heating wire, a metal wire, or a transparent conductive film) disposed on the surface or inside of an automobile windshield, and the electric heating element can generate heat to heat the automobile windshield, so as to raise the temperature of the automobile windshield, thereby achieving the functions of defrosting and defogging. The electric heating functions are all used for ensuring that the appearance and the visual performance of the glass are not influenced by fog and frost, and common specific products comprise automobile wire clamping front windshield, automobile film coating front windshield, automobile silver paste printing heating wire rear windshield, building heatable glass, show window heatable glass and the like.
In order to improve the service performance, such as safety, convenience and even automation, of such electrically heated glass, and the added value of the glass, it is often necessary to provide them with an automatic anti-fogging or defrosting function. In order to realize these functions, it is necessary to first obtain the temperature of the glass as a criterion for determining the conditions of defrosting and defogging (whether the frost layer is removed completely, whether fogging is likely to occur or whether defogging is completed, etc.) of the glass.
In the prior art, the temperature of the surface of the glass is mostly measured by common temperature sensors, for example, chinese patent CN103200717A monitors the temperature of the inner and outer surfaces of the window glass in real time by providing a temperature sensor inside the window and a temperature sensor outside the window, and chinese patent CN103402280A detects the temperature of the glass body and the outside of the glass by attaching two temperature probes to the glass; chinese patent CN103444259A also detects the temperature of the windshield by providing a plurality of temperature sensors, which are disposed inside and outside the glass or attached to the surface of the glass. In the measurement modes based on the temperature sensors, only one temperature sensor can measure one temperature point, when the glass temperature is unevenly distributed and the integral temperature of the glass needs to be measured, a plurality of temperature sensors need to be arranged in each temperature characteristic area, and the mode of measuring the integral temperature through multiple points is easy to cause data distortion; meanwhile, the temperature sensors arranged on the inner side, the outer side or the surface of the glass often affect the appearance and the visual effect of the glass, and are particularly applied to automobile windshields with higher safety requirements; when the temperature control device is arranged at the edge of the automobile windshield (outside the main visual area), the temperature distribution condition of the main visual area of the windshield cannot be truly and accurately reflected, and the defrosting and demisting effects are reduced. If the temperature sensor is applied to building glass or show window glass, the appearance and the visual effect of the glass are also obviously influenced by the temperature sensor, and the market competitiveness of products is reduced.
Meanwhile, after the above-mentioned manner of measuring the temperature of the glass surface by using the temperature sensor is applied to the defrosting and defogging system, the following disadvantages exist: when the glass is unevenly heated, a plurality of temperature sensors are required to accurately reflect the temperature of each area of the glass, so that defrosting and demisting are effectively carried out; for example, when the temperature sensor is disposed at the edge of the glass, the temperature of the central region (main viewing zone) cannot be faithfully reflected, and thus the central region cannot be effectively defrosted; when the temperature sensor is arranged in the central area, the appearance and visual effect of the glass can be obviously influenced, and the safety performance of the automobile during driving can be reduced for the front windshield of the automobile.
The invention content is as follows:
the invention aims to solve the technical problem that the temperature of the electric heating glass in the prior art is obviously influenced by the appearance and the optical performance of an automobile or cannot truly and accurately reflect the temperature of a main viewing area of the glass, and provides a temperature measuring system and a method for the electric heating glass, and also provides an automobile glass system capable of automatically defrosting and demisting and a defrosting method.
The technical scheme adopted by the invention for solving the technical problems is as follows: electric heating glass's temperature measurement system, including glass board, electric heating element and power, electric heating element sets up on the surface of glass board, thereby electric heating element can be heated glass board by the circular telegram, and the power can be at electric heating element's both ends loading voltage U, its characterized in that: the electric heating element is characterized by also comprising a current measuring device or a resistance measuring device, wherein the current measuring device or the resistance measuring device can measure the current I or the resistance R of the electric heating element after being electrified;
when a current measuring device is arranged in the temperature measuring system, the temperature of the electric heating element is T,
T＝T0+[U/(IR0)-1]/α；
when a resistance measuring device is arranged in the temperature measuring system, the temperature of the electric heating element is T,
T＝T0+[R/R0-1]/α；
wherein, T0At room temperature, R0Which is the resistance of the electric heating element at normal temperature, α is the temperature coefficient of resistance of the electric heating element, and the temperature of the glass sheet surface on which the electric heating element is arranged is equal to the temperature T of the electric heating element.
Further, the electric heating element is a metal wire, a printed silver paste heating wire or a transparent conductive film.
Further, when the electric heating element is in the electric heating process, the temperature T of the outer surface of the electric heating glass is heatedSAnd the temperature T of the electric heating element satisfies the following conditions:
in the formulaWherein,is the outer surface temperature, T, of the electrically heated glass at time (n +1)∞For the ambient temperature, (n +1) represents the time at which (n +1) time steps △ t have elapsed since the start of heating, △ t beingThe time step length of the temperature measuring system for recording the temperature data of the electric heating element is the thickness of the glass plate, k is the heat conductivity coefficient of the glass plate, rho is the density of the glass plate, CPThe specific heat capacity of the glass plate, and h is the heat convection coefficient between the outer surface of the electric heating glass and the external environment.
Further, when a multilayer medium is arranged between the electric heating element and the outer surface of the electric heating glass and the temperatures of the electric heating glass and the electric heating element are in a stable state, the temperature T of the outer surface of the electric heating glassSAnd the temperature T of the electric heating element satisfies the following conditions:
wherein, T∞Ambient temperature, △ xiIs the thickness of the i-th layer of dielectric, kiThe coefficient of thermal conductivity of the ith layer of medium is shown, and h is the coefficient of convective heat transfer between the outer surface of the electric heating glass and the external environment.
Meanwhile, the invention also provides a method for measuring the temperature of the electric heating glass by using the temperature measuring system, which is characterized by comprising the following steps: comprises the following steps of (a) carrying out,
step 1: measuring the resistance R of the electric heating element at room temperature0The normal temperature is denoted as T0Querying or measuring the temperature coefficient of resistance α of the electrical heating element;
step 2: loading a voltage U at two ends of the electric heating element, and then measuring a current I which is led into the electric heating element or a resistance R at two ends of the electric heating element;
and step 3: if the current I is measured in step 2, T is the equation T0+[U/(IR0)-1]The temperature T of the electric heating element is calculated out in α;
if the resistance R is measured in step 2, T is the equation T0+[R/R0-1]The temperature T of the electric heating element is calculated out in α;
the temperature of the surface of the glass sheet provided with the electric heating element is equal to the temperature T of said electric heating element.
Further, when the electric heating element is in the electric heating process, the temperature T of the outer surface of the electric heating glass is heatedSAnd the temperature T of the electric heating element satisfies the following conditions:
in the formulaWherein,is the outer surface temperature, T, of the electrically heated glass at time (n +1)∞Representing the external environment temperature, (n +1) representing the time when (n +1) time steps △ t pass after the heating begins, △ t representing the time steps for recording the temperature data of the electric heating element by the temperature measuring system, wherein the time steps are the thickness of the glass plate, k is the thermal conductivity coefficient of the glass plate, rho is the density of the glass plate, and C is the density of the glass platePThe specific heat capacity of the glass plate, and h is the heat convection coefficient between the outer surface of the electric heating glass and the external environment.
Further, when a multilayer medium is arranged between the electric heating element and the outer surface of the electric heating glass and the temperatures of the electric heating glass and the electric heating element are in a stable state, the temperature T of the outer surface of the electric heating glassSAnd the temperature T of the electric heating element satisfies the following conditions:
wherein, T∞Ambient temperature, △ xiIs the thickness of the i-th layer of dielectric, kiThe coefficient of thermal conductivity of the ith layer of medium is shown, and h is the coefficient of convective heat transfer between the outer surface of the electric heating glass and the external environment.
Due to the adoption of the technical scheme, the invention has the following beneficial effects:
the temperature measuring system and the method of the electric heating glass directly measure the current or the resistance of the electric heating element by arranging the current measuring device or the resistance measuring device, and obtain the temperature of the glass by combining the inherent resistance temperature coefficient of the electric heating element; therefore, the arrangement of a plurality of temperature sensors on the surface of the glass can be avoided, and the cost is reduced; the measured temperature is the integral equivalent temperature of the glass, so that the integral temperature distribution of the glass can be effectively reflected, and the judgment of the automatic defrosting and demisting conditions of the glass is facilitated; meanwhile, the appearance of the glass and the sight of people in the automobile or in a room are not influenced, and when the glass is applied to the front windshield of the automobile, the interference to the sight of a driver is avoided, so that the driving safety of the automobile is improved.
Description of the drawings:
FIG. 1 is a schematic circuit diagram of a temperature measuring system for electrically heated glass provided with a current measuring device;
FIG. 2 is a schematic circuit diagram of a temperature measurement system for electrically heated glass provided with a resistance measurement device;
FIG. 3 is a schematic structural view of a laminated coated glass according to the present invention;
FIG. 4 is a schematic view of an automotive glass system capable of automatic defrosting and defogging provided with a current measuring device;
FIG. 5 is a schematic view of an automotive glass system capable of automatic defrosting and defogging provided with a resistance measurement device;
FIG. 6 is a graphical representation of the relationship between the moisture content of the air and the dew point temperature in accordance with the present invention;
in the figure: 1, a glass plate; 2, an electric heating element; 3, a power supply; 5, a control unit; 6, a humidity sensor; 10, an electrode; 41, a current measuring device; 42, a resistance measuring device; 100, outer glass; 101, inner glass; 102, PVB film sheet.
The specific implementation mode is as follows:
as shown in fig. 1 and 2, the temperature measuring system for electrically heated glass according to the present invention comprises a glass plate 1, an electric heating element 2 and a power supply 3, wherein the electric heating element 2 is disposed on the surface of the glass plate 1, the electric heating element 2 can be electrically heated to heat the glass plate 1, and the power supply 3 can apply a voltage U across the electric heating element 2, and is characterized in that: the electric heating element also comprises a current measuring device or a resistance measuring device, wherein the current measuring device or the resistance measuring device can measure the current I or the resistance R of the electric heating element 2 after being electrified; in this way, the temperature of the electric heating element 2 is obtained by directly providing a current measuring device or a resistance measuring device in the electric circuit formed by the electric heating element 2 and the power source 3, directly measuring the current or the resistance of the electric heating element 2, and combining the inherent temperature coefficient of resistance of the electric heating element 2 itself.
In fig. 1, a current measuring device 41 is shown, when the current measuring device 41 is provided in the temperature measuring system, the temperature of the electric heating element 2 is T,
T＝T0+[U/(IR0)-1]/α；
in fig. 2, the resistance measuring device 42 is shown, and when the resistance measuring device 42 is provided in the temperature measuring system, the temperature of the electric heating element 2 is T,
T＝T0+[R/R0-1]/α；
wherein, T0At room temperature, R0Is the resistance of the electric heating element at the normal temperature, α is the resistance temperature coefficient of the electric heating element, and the normal temperature T can be adjusted according to the invention0The temperature was measured as 23 ℃.
The current measuring device 41 may be a high-precision dc ammeter, and the resistance measuring device 42 may be a micro-ohmmeter, a digital ohmmeter, or the like, which are commercially available.
Specifically, the temperature coefficient of resistance α is used to characterize the resistivity or resistance of a conductor as a function of temperature, and is defined as the ratio of the increase in resistance of the conductor to the original resistance in ppm/deg.C (i.e., 10) for each 1 deg.C increase in temperature-6In general, the temperature coefficient of resistance α of a commonly used metal conductor is constant, i.e., the resistivity is linear with respect to temperature, and then when the temperature is T, the resistivity of the conductor is:
ρT＝ρ0(1+α△T)；
where ρ is0Is a temperature T0The resistivity of the conductor at time, temperature difference △ T ═ T-T0The relationship between the resistance and the temperature of the electric heating element 2 is then:
RT＝R0(1+α△T)；
at this time, if the normal temperature T is known0Resistance R of the electrical heating element 20And knowing the temperature coefficient of resistance α of the electric heating element 2, once the resistance R of the electric heating element 2 is measured, the temperature T of the electric heating element 2 at that time can be found:
T＝T0+[R/R0-1]/α；
in practical applications, the value of the current I through the electric heating element 2 may also be measured, and since I ═ U/R, the temperature T of the electric heating element 2 at that time may also be derived:
T＝T0+[U/(IR0)-1]/α；
in the present invention, the electric heating element 2 is a metal wire, a heating wire printed with silver paste, a transparent conductive film or a conductor made of other materials, which are commonly used in the art, and the resistance temperature coefficient α is constant or can be regarded as constant, and the resistance R is constant at the normal temperature (for example, 23 ℃)0Can be directly measured by a resistance meter, wherein the resistance temperature coefficient α can be obtained by the known literatureThe resistance temperature coefficient α can be obtained by measuring the resistance values of conductors under different environmental temperatures and then calculating, for example, the sheet resistance of the transparent conductive film in the coated product is measured to be 1.0-4.0 m omega/□, and the resistance temperature coefficient is measured to be 0.001-0.002 (1/DEG C).
Usually, the electric heating element 2 is arranged on the surface of the glass plate 1 and has a very thin thickness, for example, in the rear glass of an automotive silver paste printing heating wire, since the electric heating element 2, i.e. the printing heating wire, is printed on the glass surface, the measured temperature T is the temperature of the printing heating wire surface; for example, in a wired front windshield of an automobile, the electric heating element 2 is a tungsten wire sandwiched between two glass plates, and the measured temperature T is the temperature of the surface of the glass plate where the tungsten wire is located (which can also be regarded as the internal temperature of the laminated glass); for example, in the automobile coated front windshield, the electric heating element 2 is a transparent conductive film coated on the surface of the glass plate, and the measured temperature T is the temperature of the surface of the glass plate where the transparent conductive film is located; thus, although the temperature of the electric heating element 2 is measured as described above, the electric heating element 2 is arranged directly on the surface of the single glass sheet or inside the laminated glass, so that the temperature of the electric heating element 2 is the temperature of the surface of the glass sheet on which it is arranged, i.e. the temperature of the surface of the glass sheet on which the electric heating element 2 is arranged is equal to the temperature T of said electric heating element 2.
When a plurality of layers of media are arranged between the electric heating element 2 and the outer surface of the electric heating glass and the temperatures of the electric heating glass and the electric heating element 2 are in a stable state, the temperature T of the outer surface of the electric heating glassSAnd the temperature T of the electric heating element 2 satisfies:
wherein, T∞Ambient temperature, △ xiIs the thickness of the i-th layer of dielectric, kiIs the heat conductivity coefficient of the ith layer of medium, and h is the appearance of the electrically heated glassThe convective heat transfer coefficient of the face to the external environment.
As shown in fig. 3, taking a laminated coated glass as an example, which is composed of 2.1mm outer glass 100, 0.76mm pvb film 102, transparent conductive film 2 and 2.1mm inner glass 101, heating is performed under the condition that the external environment temperature is 23 ℃, and after obtaining the temperature of the electric heating element 2, the temperature of the inner surface of the inner glass 101 can be calculated by the above formula, as shown in table 1 specifically:
table 1: temperature distribution of laminated coated glass in steady state
| Temperature (. degree. C.) of transparent conductive film | 30 | 40 | 50 | 60 |
| Temperature of true inner surface (. degree. C.) | 30 | 40 | 49 | 59 |
| Calculated temperature of inner surface (. degree. C.) | 30 | 40 | 49 | 60 |
Meanwhile, when the electric heating element 2 is in the electric heating process, the temperature T of the outer surface of the electric heating glassSAnd the temperature T of the electric heating element satisfies the following conditions:
in the formulaWherein,is the outer surface temperature, T, of the electrically heated glass at time (n +1)∞Representing the external environment temperature, (n +1) representing the time when (n +1) time steps △ t pass after the heating begins, △ t representing the time steps for recording the temperature data of the electric heating element by the temperature measuring system, wherein the time steps are the thickness of the glass plate, k is the thermal conductivity coefficient of the glass plate, rho is the density of the glass plate, and C is the density of the glass platePThe specific heat capacity of the glass plate, and h is the heat convection coefficient between the outer surface of the electric heating glass and the external environment.
As shown in FIG. 3, the laminated coated glass is composed of 2.1mm outer glass 100, 0.76mm PVB membrane 102, transparent conductive film 2 and 2.1mm inner glass 101, and is prepared by respectively using 400, 600 and 800w/m at 23 deg.C2The step length of the temperature acquisition time of the electric heating element 2 is 0.5s, and the temperature of the inner surface of the inner glass 101 can be calculated by the formula, which is specifically shown in table 2:
table 2: temperature distribution of laminated coated glass in electrical heating process
In fig. 1 and 2, the temperature measuring system for electrically heated glass further includes a control unit 5, where the control unit 5 receives data transmitted in real time by the current measuring device 41 or the resistance measuring device 42, and calculates a corresponding real-time temperature of the glass; and the output voltage of the power supply 3 can be correspondingly reduced or increased through the additionally arranged inverter according to the temperature measured in real time, so that the heating efficiency of the electrically heated glass is reduced or increased, and the defrosting and demisting effects of the glass are improved.
Meanwhile, the temperature measuring method is concretely explained by combining the temperature measuring system of the electric heating glass, and the method comprises the following steps,
step 1: at normal temperature, the resistance R of the electric heating element 2 was measured0The normal temperature is denoted as T0Querying or measuring the temperature coefficient of resistance α of the electrical heating element;
in the present invention, for convenience of unified description, the normal temperature is 23 ℃. Accordingly, when the electric heating element 2 is a tungsten wire, the temperature coefficient of resistance α thereof is 0.0051 (1/deg.C) by searching; if the electric heating element 2 adopts a transparent conductive film, the film surface sheet resistance of the transparent conductive film in the coated product of my department is 1.0-4.0 m omega/□, the resistance temperature coefficient is 0.001-0.002 (1/DEG C), and the specific numerical value is determined according to different conductive films in the actual product.
Step 2: applying a voltage U across the electric heating element 2, and then measuring the current I passing through the electric heating element 2 or the resistance R across the electric heating element;
specifically, a voltage U is applied across the electric heating element 2 by the power supply 3 to constitute an energization loop, and a current measuring device 41 or a resistance measuring device 42 is provided in the energization loop to directly measure the current I or the resistance R of the electric heating element 2.
And step 3: if the current I is measured in step 2, T is the equation T0+[U/(IR0)-1]The temperature T of the electric heating element 2 is calculated out from/α;
if the resistance R is measured in step 2,then the formula T ═ T is used0+[R/R0-1]The temperature T of the electric heating element 2 is calculated out from/α;
the temperature of the surface of the glass sheet provided with the electric heating element 2 is equal to the temperature T of said electric heating element.
Wherein, when a plurality of layers of media are arranged between the electric heating element 2 and the outer surface of the electric heating glass and the temperatures of the electric heating glass and the electric heating element 2 are in a stable state, the temperature T of the outer surface of the electric heating glassSAnd the temperature T of the electric heating element 2 satisfies:
wherein, T∞Ambient temperature, △ xiIs the thickness of the i-th layer of dielectric, kiThe coefficient of thermal conductivity of the ith layer of medium is shown, and h is the coefficient of convective heat transfer between the outer surface of the electric heating glass and the external environment.
Wherein, when the electric heating element 2 is in the electric heating process, the temperature T of the outer surface of the electric heating glassSAnd the temperature T of the electric heating element satisfies the following conditions:
in the formulaWherein,outer surface temperature of electrically heated glass at time T∞Representing the external environment temperature, (n +1) representing the time when (n +1) time steps △ t pass after the heating begins, △ t representing the time steps for recording the temperature data of the electric heating element by the temperature measuring system, wherein the time steps are the thickness of the glass plate, k is the thermal conductivity coefficient of the glass plate, rho is the density of the glass plate, and C is the density of the glass platePIs glassThe specific heat capacity of the plate, h is the convective heat transfer coefficient between the outer surface of the electrically heated glass and the external environment.
In the invention, the data obtained in step 1 and step 2 are transmitted to the control unit 5, and the corresponding real-time temperature is calculated in the control unit 5. Meanwhile, the control unit 5 can also judge the power requirements for defrosting and demisting according to the temperature measured in real time, and further adjust the output voltage of the power supply 3 in real time.
The system and the method for measuring the temperature of the electrically heated glass can avoid arranging a plurality of temperature sensors on the surface of the glass, so that the appearance and the optical performance of the glass are not influenced completely, the temperature of a main viewing area of the glass can be reflected effectively, and an automobile glass system capable of automatically defrosting and demisting and an automatic demisting and defrosting method can be further designed on the basis.
As shown in fig. 4 and 5, the automobile glass system capable of automatically defrosting and demisting according to the present invention includes an automobile glass and a power supply 3, the automobile glass is provided with an electric heating element 2 capable of being electrified to generate heat so as to heat the automobile glass, the power supply 3 can apply a voltage U across the electric heating element 2, and the automobile glass system is characterized in that: the automobile air conditioner further comprises a control unit 5, a humidity sensor 6 and a current measuring device or a resistance measuring device, wherein the humidity sensor 6 is arranged in the automobile to measure the moisture content d of air in the automobile, and the current measuring device or the resistance measuring device can measure the current I or the resistance R of the electric heating element 2 after being electrified; thus, the current measuring device or the resistance measuring device is directly arranged in an electrifying loop formed by the electric heating element 2 and the power supply 3, the current or the resistance of the electric heating element 2 is directly measured, the measured temperature is obtained by combining the inherent resistance temperature coefficient of the electric heating element 2, and the moisture content in the automobile is measured by the humidity sensor 6, the measured physical quantities are input into the control unit 5 for calculation and processing, the defrosting and defogging conditions of the automobile glass are judged, and then the control unit 5 inputs corresponding control signals to control (turn on, turn off, increase and decrease) the voltage loaded at the two ends of the electric heating element 2 by the power supply 3, so that the electric heating power control of the automobile glass is realized, and the automobile glass system can realize the automatic defrosting and defogging functions.
In fig. 4, a current measuring device 41 is shown, when the current measuring device 41 is provided in the automotive glazing system, the temperature of the electric heating element 2 is T,
T＝T0+[U/(IR0)-1]/α；
in fig. 5, a resistance measuring device 42 is shown, and when the resistance measuring device 42 is provided in the automotive glazing system, the temperature of the electric heating element 2 is T,
T＝T0+[R/R0-1]/α；
wherein, T0At room temperature (e.g., 23 ℃), R0Resistance of the electric heating element 2 at normal temperature, and resistance temperature coefficient of the electric heating element 2 of α;
when the temperature T of the electric heating element 2 is less than or equal to the minimum demisting critical temperature Tfog,minMeanwhile, the control unit 5 controls the power supply 3 to apply voltage to the two ends of the electric heating element 2 to start defogging heating; wherein, Tfog,min＝Td+△Tfog,min，TdDew point temperature corresponding to moisture content d, △ Tfog,minThe demisting experiment results are determined according to different temperatures and humidities, and specific numerical values can be set according to actual conditions; preferably 2-4 ℃, so that the glass can be effectively prevented from fogging, and energy can be saved.
When the temperature T of the electric heating element 2 is more than the maximum demisting critical temperature Tfog,maxWhen the electric heating element 2 is in the heating state, the control unit 5 controls the power supply 3 to stop applying voltage to the two ends of the electric heating element 2 to stop defogging heating; wherein, Tfog,max＝Td+△Tfog,max，TdDew point temperature corresponding to moisture content d, △ Tfog,maxThe demisting experiment results are determined according to different temperatures and humidities, and specific numerical values can be set according to actual conditions; preferably 6-12 ℃, so that the phenomenon of effectively preventing the corrosion can be effectively avoidedThe glass is fogged and the energy is saved.
When the temperature T of the electric heating element 2 is higher than the safe defrosting temperature TfrostWhen the defrosting heating is turned off, the control unit 5 controls the power supply 3 to stop applying voltage to the two ends of the electric heating element 2; wherein, Tfrost＝0℃+△Tfrost，△TfrostThe defrosting safety threshold is a value determined according to defrosting experiment results of different temperatures; preferably, the temperature is 4-10 ℃, so that the defrosting can be determined to be completely removed, the defrosting heating can be stopped in time, and the energy is saved.
Specifically, △ Tfog,min、△Tfog,maxAnd △ TfrostThe fixed parameter values set according to the specific travel environment, which are related to the ambient temperature of the driving area of the automobile, the specification and size of the automobile glass, the overall arrangement shape of the electric heating element 2, etc., are generally set properly in consideration of comprehensive consideration. Taking the laminated coated glass (2.1mm +0.76mm +1.9mm) as an example, the overall layout shape of the electric heating element 2 is rectangular, and the following specific settings are given in table 3:
table 3: specific parameter setting of laminated coated glass
Wherein, the dew point temperature T corresponding to the moisture content d of the air in the vehicle can be obtained according to the query result of the thermal and physical property handbook of engineering common substances and the attached figure 6dIn FIG. 4, the curve a represents the maximum defogging critical temperature Tfog,maxAnd curve b represents the minimum demisting critical temperature Tfog,minCurve c represents the dew point temperature TdAnd judging whether the inner surface of the automobile glass has the fogging or not by combining the temperature T of the electric heating element 2, namely when the temperature T of the electric heating element 2 is more than the dew point temperature TdWhen the humidity of the air near the surface of the glass plate in the automobile is not saturated, the fog cannot be generated; when the temperature T of the electric heating element 2 is less than or equal to the dew point temperature TdWhen the humidity of the air near the surface of the glass sheet in the vehicle is saturated or supersaturated, fogging will start, and the degree of fogging will depend on the temperature difference between the two. In this way, it is clear that it is only necessary to ensure that the temperature T of the electric heating element 2 is greater than the dew point temperature TdFogging can be prevented. In order to improve the defogging effect and save energy, the highest defogging critical temperature T is setfog,maxAnd minimum demisting critical temperature Tfog,minI.e. when the temperature T of the electric heating element 2 is less than or equal to the minimum demisting threshold temperature Tfog,minMeanwhile, demisting and heating are started; when the temperature T of the electric heating element 2 is more than the maximum demisting critical temperature Tfog,maxAnd when the temperature is higher than the preset temperature, the demisting heating is turned off.
Preferably, the control unit 5 monitors the temperature T of the electric heating element 2 every 0.5-10 seconds to meet the requirements of defrosting and demisting, and the specific time interval value is set according to actual conditions.
In the present invention, the electric heating element 2 is a metal wire, a heating wire printed with silver paste, a transparent conductive film or a conductor made of other materials, which are commonly used in the art, and the resistance temperature coefficient α is constant or can be regarded as constant, and the resistance R is constant at the normal temperature (for example, 23 ℃)0The resistance temperature coefficient α can be obtained by direct measurement of a resistance meter, wherein the resistance temperature coefficient α can be obtained by inquiry in a known literature, for example, a tungsten wire commonly used as an electric heating element, the resistance temperature coefficient table of commonly used metal is inquired to be 0.0051 (1/DEG C), and the resistance temperature coefficient α can be obtained by measuring the resistance values of conductors under different environmental temperatures and calculating, for example, the sheet resistance of a transparent conductive film in a coating product is measured to be 1.0-4.0 m omega/□, and the resistance temperature coefficient is measured to be 0.001-0.002 (1/DEG C).
The specific automatic defogging method for the automobile glass system capable of automatically defrosting and defogging is characterized by comprising the following steps of: the method comprises the following steps:
step 1: measuring the moisture content d of the air in the automobile, and obtaining the corresponding dew point temperature T according to the moisture content dd；
Measuring the moisture content d of air by using a humidity sensor 6 in the vehicle, and inquiring according to a thermal and physical property manual of engineering common substances to obtain the corresponding dew point temperature Td。
Step 2: applying a voltage U across the electric heating element 2, and then measuring the current I passing through the electric heating element 2 or the resistance R across the electric heating element;
if the current I is measured, T is determined by the formula T0+[U/(IR0)-1]Calculating the temperature T of the electric heating element by/α;
if the resistance R is measured, T is determined by the formula T0+[R/R0-1]Calculating the temperature T of the electric heating element by/α;
wherein, T0Is a room temperature (e.g., 23 ℃), and α is a temperature coefficient of resistance of the electric heating element 2;
and step 3: the temperature T of the electric heating element 2 is compared with the minimum demisting critical temperature Tfog,minComparing when the temperature T is less than or equal to Tfog,minWhen the electric heating element is used, voltage is loaded at two ends of the electric heating element to start demisting and heating;
wherein, Tfog,min＝Td+△Tfog,min，TdThe dew point temperature corresponding to the moisture content d, here △ Tfog,minThe demisting experiment results are determined according to different temperatures and humidities, and specific numerical values can be set according to actual conditions; preferably 2-4 ℃, so that the glass can be effectively prevented from fogging, and energy can be saved.
And 4, step 4: the temperature T of the electric heating element 2 and the maximum demisting critical temperature Tfog,maxComparing;
wherein, Tfog,max＝Td+△Tfog,max，TdThe dew point temperature corresponding to the moisture content d, here △ Tfog,maxAlso is a numerical value determined according to demisting experimental results of different temperature and humidity, and the specific numerical value can be determined according to the factSetting the situation; preferably 6-12 ℃, so that the glass can be effectively prevented from fogging, and energy can be saved.
And 5: if the temperature T of the electric heating element 2 is greater than the maximum demisting critical temperature Tfog,maxNo longer applying a voltage across the electrical heating element to turn off defogging heating; otherwise, repeating the steps 2-4.
Preferably, the time interval for repeating the steps 2-4 in the step 5 is 0.5-10 seconds to meet the requirement of defogging, and the specific time interval value is set according to the actual situation.
The specific automatic defrosting method of the automobile glass system capable of automatically defrosting and demisting is characterized by comprising the following steps of: the method comprises the following steps:
step 1: loading a voltage U at two ends of the electric heating element 2 to electrify the electric heating element 2 to generate heat so as to heat the automobile glass to defrost;
the step can be started manually or in a reserved mode, and the reserved starting is realized by starting the defrosting and heating functions of the automobile glass in advance according to the next starting time of the automobile, which is set in advance by a driver, of the automobile through an electronic control component, a driving computer, mobile phone App software and the like connected with the defrosting system.
Step 2: measuring the current I through the electric heating element 2 or the resistance R across the electric heating element;
if the current I is measured, T is determined by the formula T0+[U/(IR0)-1]Calculating the temperature T of the electric heating element by/α;
if the resistance R is measured, T is determined by the formula T0+[R/R0-1]Calculating the temperature T of the electric heating element by/α;
wherein, T0Is a room temperature (e.g., 23 ℃), α is the temperature coefficient of resistance of the electrical heating element;
and step 3: setting the temperature T of the electric heating element to a safe defrosting temperatureDegree TfrostComparing;
wherein, Tfrost＝0℃+△Tfrost，△TfrostFor a set defrost safety threshold, △ TfrostThe temperature can be set according to specific practical conditions, and is preferably 4-10 ℃, so that the frost layer can be completely removed, and the purpose of saving energy can be achieved.
And 4, step 4: if the temperature T of the electric heating element is more than the safe defrosting temperature TfrostNo longer applying a voltage across the electrical heating element to turn off defrost heating; otherwise, continuing to apply voltage across the electrical heating element and repeating steps 2 and 3.
Preferably, the time interval for repeating the steps 2 and 3 in the step 4 is 0.5-10 seconds to meet the defrosting requirement, and the specific time interval value is set according to the actual situation.
The automobile glass system capable of automatically defrosting and demisting and the demisting and defrosting methods can ensure that the automobile glass is not fogged in real time, avoid the potential safety hazard that the fogging of the glass affects the sight of a driver, improve the safety performance and comfort of automobile driving and achieve better energy-saving effect at the same time; and when the defrosting operation, simplified driver's operation, close the defrosting heating function in the very first time that the defrosting was accomplished, avoid unnecessary energy waste, reduce the time that the driver waited for in the defrosting process, strengthened user experience.
The above description specifically describes the system and method for measuring temperature of electrically heated glass according to the present invention, and also specifically describes an automotive glass system capable of automatically defrosting and defogging and a method for defogging and defrosting, but the present invention is not limited by the above description, and therefore, any improvements, equivalent modifications, substitutions, etc. made in accordance with the technical gist of the present invention are intended to be within the scope of the present invention.
Claims (5)
1. Electric heating glass's temperature measurement system, including glass board, electric heating element and power, electric heating element sets up on the surface of glass board, thereby electric heating element can be heated glass board by the circular telegram, and the power can be at electric heating element's both ends loading voltage U, its characterized in that: the electric heating element is characterized by also comprising a current measuring device or a resistance measuring device, wherein the current measuring device or the resistance measuring device can measure the current I or the resistance R of the electric heating element after being electrified;
when a current measuring device is arranged in the temperature measuring system, the temperature of the electric heating element is T,
T＝T0+[U/(IR0)-1]/α；
when a resistance measuring device is arranged in the temperature measuring system, the temperature of the electric heating element is T,
T＝T0+[R/R0-1]/α；
wherein, T0At room temperature, R0The resistance of the electric heating element at the normal temperature is shown as α, and the temperature of the surface of the glass plate provided with the electric heating element is equal to the temperature T of the electric heating element;
when the electric heating element is in the electric heating process, the temperature T of the outer surface of the electric heating glassSAnd the temperature T of the electric heating element satisfies the following conditions:
in the formulaA0＝1，B0＝0，C0＝0，D01 is ═ 1; wherein, is the outer surface temperature, T, of the electrically heated glass at time (n +1)∞Representing the time when (n +1) time steps deltat pass after the heating begins, wherein deltat is the time step of the temperature measuring system for recording the temperature data of the electric heating element, is the thickness of the glass plate, k is the thermal conductivity coefficient of the glass plate, rho is the density of the glass plate, and C +1 represents the temperature of the external environmentPThe specific heat capacity of the glass plate, and h is the heat convection coefficient between the outer surface of the electric heating glass and the external environment.
2. The system for measuring the temperature of an electrically heated glass as claimed in claim 1, wherein: the electric heating element is a metal wire, a printing silver paste heating wire or a transparent conductive film.
3. The system for measuring the temperature of an electrically heated glass as claimed in claim 1, wherein: when a plurality of layers of media are arranged between the electric heating element and the outer surface of the electric heating glass and the temperatures of the electric heating glass and the electric heating element are in a stable state, the temperature T of the outer surface of the electric heating glassSAnd the temperature T of the electric heating element satisfies the following conditions:
wherein, T∞Is the ambient temperature, Δ xiIs the thickness of the i-th layer of dielectric, kiThe coefficient of thermal conductivity of the ith layer of medium is shown, and h is the coefficient of convective heat transfer between the outer surface of the electric heating glass and the external environment.
4. A method for measuring the temperature of an electrically heated glass using the temperature measuring system according to any one of claims 1 to 3, wherein: comprises the following steps of (a) carrying out,
step 1: measuring the resistance R of the electric heating element at room temperature0The normal temperature is denoted as T0Querying or measuring the temperature coefficient of resistance α of the electrical heating element;
step 2: loading a voltage U at two ends of the electric heating element, and then measuring a current I which is led into the electric heating element or a resistance R at two ends of the electric heating element;
and step 3: if the current I is measured in step 2, T is the equation T0+[U/(IR0)-1]The temperature T of the electric heating element is calculated out in α;
if the resistance R is measured in step 2, T is the equation T0+[R/R0-1]The temperature T of the electric heating element is calculated out in α;
the temperature of the surface of the glass sheet provided with the electric heating element is equal to the temperature T of the electric heating element;
when the electric heating element is in the electric heating process, the temperature T of the outer surface of the electric heating glassSAnd the temperature T of the electric heating element satisfies the following conditions:
in the formulaA0＝1，B0＝0，C0＝0，D01 is ═ 1; wherein, is the outer surface temperature, T, of the electrically heated glass at time (n +1)∞Representing the time when (n +1) time steps deltat pass after the heating begins, wherein deltat is the time step of the temperature measuring system for recording the temperature data of the electric heating element, is the thickness of the glass plate, k is the thermal conductivity coefficient of the glass plate, rho is the density of the glass plate, and C +1 represents the temperature of the external environmentPThe specific heat capacity of the glass plate, and h is the heat convection coefficient between the outer surface of the electric heating glass and the external environment.
5. The system for measuring the temperature of an electrically heated glass as set forth in claim 4, wherein: when a plurality of heating elements are arranged between the electric heating element and the outer surface of the electric heating glassThe temperature T of the outer surface of the electric heating glass is stable when the temperature of the electric heating glass and the electric heating element is in a stable stateSAnd the temperature T of the electric heating element satisfies the following conditions:
wherein, T∞Is the ambient temperature, Δ xiIs the thickness of the i-th layer of dielectric, kiThe coefficient of thermal conductivity of the ith layer of medium is shown, and h is the coefficient of convective heat transfer between the outer surface of the electric heating glass and the external environment.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410584493.8A CN104406708B (en) | 2014-10-27 | 2014-10-27 | The temperature measurement system and method for electrically heated glass |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410584493.8A CN104406708B (en) | 2014-10-27 | 2014-10-27 | The temperature measurement system and method for electrically heated glass |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN104406708A CN104406708A (en) | 2015-03-11 |
| CN104406708B true CN104406708B (en) | 2017-03-29 |
Family
ID=52644355
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201410584493.8A Active CN104406708B (en) | 2014-10-27 | 2014-10-27 | The temperature measurement system and method for electrically heated glass |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN104406708B (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108458799A (en) * | 2017-12-22 | 2018-08-28 | 兰州空间技术物理研究所 | A kind of hollow cathode emitter temperature online diagnostic method based on C-V characteristic |
| CN110274705B (en) * | 2018-03-14 | 2021-06-22 | 香港理工大学 | Optical glass mould pressing temperature online detection method and device |
| CN111006784B (en) * | 2019-12-21 | 2021-07-13 | 广东天际电器股份有限公司 | Dry burning judgment method applied to PTC heating equipment |
| DE102023117974A1 (en) * | 2023-07-07 | 2025-01-09 | Sick Ag | Embedded temperature sensor for a windshield heater |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA988324A (en) * | 1971-11-16 | 1976-05-04 | Ppg Industries, Inc. | Electrically heated window with a temperature sensor |
| JP2002289520A (en) * | 2001-03-23 | 2002-10-04 | Japan Science & Technology Corp | Pulse heat treatment method and heat treatment apparatus using thin film heating element |
| CN1548934A (en) * | 2003-05-07 | 2004-11-24 | 刘正洪 | Temperature sensor, its temperature detecting circuit and method |
| WO2007091299A1 (en) * | 2006-02-07 | 2007-08-16 | Shimadzu Corporation | Method for heating tft substrate, temperature measuring method for tft substrate, and temperature control method for tft substrate |
| CN102595943A (en) * | 2009-10-29 | 2012-07-18 | 菲利普莫里斯生产公司 | An electrically heated smoking system with improved heater |
-
2014
- 2014-10-27 CN CN201410584493.8A patent/CN104406708B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA988324A (en) * | 1971-11-16 | 1976-05-04 | Ppg Industries, Inc. | Electrically heated window with a temperature sensor |
| JP2002289520A (en) * | 2001-03-23 | 2002-10-04 | Japan Science & Technology Corp | Pulse heat treatment method and heat treatment apparatus using thin film heating element |
| CN1548934A (en) * | 2003-05-07 | 2004-11-24 | 刘正洪 | Temperature sensor, its temperature detecting circuit and method |
| WO2007091299A1 (en) * | 2006-02-07 | 2007-08-16 | Shimadzu Corporation | Method for heating tft substrate, temperature measuring method for tft substrate, and temperature control method for tft substrate |
| TWI301313B (en) * | 2006-02-07 | 2008-09-21 | Shimadzu Corp | Heating method of tft substrate, temperature measuring method of tft substrate and temperature controlling method of tft substrate |
| CN102595943A (en) * | 2009-10-29 | 2012-07-18 | 菲利普莫里斯生产公司 | An electrically heated smoking system with improved heater |
Also Published As
| Publication number | Publication date |
|---|---|
| CN104406708A (en) | 2015-03-11 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN104470010B (en) | Can the car glass system of automatic defrosting demist and demist, defrosting method | |
| CN104406708B (en) | The temperature measurement system and method for electrically heated glass | |
| US10661755B2 (en) | Arrangement for de-icing a transparent window with an electric heating device | |
| EP1747700B1 (en) | High performance defrosters for transparent panels | |
| EP3400753B1 (en) | Heatable glazing | |
| US20120199569A1 (en) | Heatable glazing | |
| JP2014502408A (en) | Panel heater with temperature monitoring function | |
| US10356851B2 (en) | Transparent pane having an electrical heating layer, method for the production thereof, and use thereof | |
| CN102438342A (en) | Vehicle window glass with heating function | |
| JP7402803B2 (en) | Method and composition for deicing a transparent window using an electric heating device | |
| CN201119031Y (en) | Heat reflection coated laminated glass capable of being intelligently and electrically heated | |
| WO2015010357A1 (en) | Automatic defogging glass and preparation method therefor | |
| CN204180311U (en) | A kind of electrically heated glass | |
| KR101405120B1 (en) | Apparatus for removing frost of vehicle glass | |
| CN206096684U (en) | Liquid crystal display | |
| CA1295004C (en) | Discontinuity detector in a heated transparency | |
| US20230073820A1 (en) | Vehicle pane with integrated temperature sensor | |
| CN103228069B (en) | Heatable transparent window board | |
| CN202924913U (en) | Vehicle-mounted flexible conductive glass assembly | |
| CN111034350A (en) | Glass heating device with intelligent monitoring and method for controlling glass heating device | |
| CN120245914A (en) | Vehicle-mounted glass heating control system, method and vehicle | |
| CN218197847U (en) | Windshield and driving device | |
| CN113728733B (en) | Heating grid design device and method | |
| CN206884336U (en) | Laminated glass and automobile | |
| CN114838952A (en) | A kind of test method and equipment for verifying the heating effect of graphene interior of electric vehicle |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |