Heating Control System and Windshield

Abstract

A heating control system for controlling a heating element provided to glass that partitions the inside and outside of a moving body, said system comprising: a sensor information acquisition unit that acquires sensor information from at least one sensor; and a control processing unit that, on the basis of the sensor information, controls a first heating element provided to a first region of the glass and a second heating element provided to a second region of the glass different from the first region, wherein the control processing unit includes a temperature difference reduction processing unit that executes a temperature difference reduction process for controlling at least one of the first heating element and the second heating element such that the temperature difference between the glass temperature in a third region of the glass between the first region and the second region, and the glass temperature in the first region or the glass temperature in the second region does not exceed an upper limit value.

Description

[Technical field]

[0001] SUMMARY The present disclosure relates to a heating control system for a windshield and the windshield. [Background technology]

[0002] Windshields are known that have heating elements located in each of two separate areas of the glass. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-216193 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the conventional technology as described above, there is a risk of a region (referred to as an "intermediate region" in this paragraph) occurring between the two regions where the heating elements are arranged, in which the difference in glass temperature becomes large with respect to the two regions. If the difference in glass temperature in the intermediate region becomes excessive with respect to the region where the heating elements are arranged, glass defects may occur in the intermediate region due to the temperature difference.

[0005] Thus, in one aspect, the present invention aims to reduce the likelihood of glass defects occurring in areas between areas where heating elements are located. [Means for solving the problem]

[0006] In one aspect, a heating control system for controlling a heating element provided on glass separating an interior and exterior of a moving body, comprising: a sensor information acquisition unit that acquires sensor information from one or more sensors; and a control processing unit that controls a first heating element provided in a first region of the glass and a second heating element provided in a second region of the glass different from the first region based on the sensor information, The control processing unit includes a temperature difference reduction processing unit that executes a temperature difference reduction process that controls at least one of the first heating element and the second heating element so that the temperature difference between the glass temperature in a third region between the first region and the second region of the glass and the glass temperature in the first region or the glass temperature in the second region does not exceed an upper limit value. Effect of the Invention

[0007] In one aspect, the present invention makes it possible to reduce the likelihood of glass defects occurring in areas between areas where heating elements are located. [Brief description of the drawings]

[0008] [Figure 1] 1 is a schematic diagram of a vehicle windshield according to a first embodiment. [Diagram 2] FIG. 2 is an enlarged view of part Q1 in FIG. [Diagram 3] FIG. 3 is a schematic cross-sectional view taken along line AA in FIG. 2. [Figure 4] 2 is a schematic diagram of a control system for a vehicle windshield. FIG. [Diagram 5] FIG. 4 is a functional diagram showing functions of a control device related to windshield heating control. [Figure 6] FIG. 11 is an explanatory diagram of threshold information. [Figure 7] FIG. 11 is an explanatory diagram of the cause of defects (eg, cracks) that may occur in the third region. [Figure 8A] 13 is an explanatory diagram (part 1) of a case where the temperature difference reducing process is executed in a situation where only the second current application process is executed. FIG. [Figure 8B] FIG. 11 is an explanatory diagram (part 2) of a case where the temperature difference reducing process is executed in a situation where only the second current application process is executed. [Figure 8C]FIG. 11 is an explanatory diagram (part 3) of a case where the temperature difference reducing process is executed in a situation where only the second current application process is executed. [Figure 8D] FIG. 11 is an explanatory diagram (part 4) of a case where the temperature difference reducing process is executed in a situation where only the second current application process is executed. [Figure 9A] 13 is an explanatory diagram (part 1) of a case where a temperature difference reducing process is executed under a condition in which a first current supply process and a second current supply process are executed. FIG. [Figure 9B] FIG. 11 is an explanatory diagram (part 2) of a case where the temperature difference reducing process is executed under a condition in which the first current supply process and the second current supply process are being executed. [Figure 9C] FIG. 11 is an explanatory diagram (part 3) of a case where the temperature difference reducing process is executed under a condition in which the first current supply process and the second current supply process are being executed. [Figure 9D] FIG. 11 is an explanatory diagram (part 4) of a case where the temperature difference reducing process is executed under a condition in which the first current supply process and the second current supply process are being executed. [Figure 10A] FIG. 11 is an explanatory diagram (part 1) of a case where the temperature difference reducing process is performed in a situation where only the second current application process is being performed when the distance between the first region and the second region is relatively large. [Figure 10B] FIG. 13 is an explanatory diagram (part 2) of a case where the temperature difference reducing process is performed in a situation where only the second current application process is being performed when the distance between the first region and the second region is relatively large. [Figure 10C] FIG. 11 is an explanatory diagram (part 3) of a case where the temperature difference reducing process is performed in a situation where only the second current application process is being performed when the distance between the first region and the second region is relatively large. [Figure 10D] FIG. 11 is an explanatory diagram (part 4) of a case where the temperature difference reducing process is performed in a situation where only the second current application process is being performed when the distance between the first region and the second region is relatively large. [Figure 11] 4 is a schematic flowchart showing an example of a process executed by a control device according to the present embodiment in relation to windshield heating control. [Figure 12] 12 is a schematic flowchart showing an example of a first heating element control process (step S2 in FIG. 11). [Figure 13] 12 is a schematic flowchart showing an example of a second heating element control process (step S3 in FIG. 11). [Figure 14] 10 is an enlarged view of a portion of a vehicle windshield 1A according to a second embodiment. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Each embodiment will be described in detail below with reference to the accompanying drawings. In the accompanying drawings, for ease of viewing, only some of the parts having the same attribute may be given reference symbols. In addition, in the drawings for explaining the form, unless otherwise specified, the direction refers to the direction on the drawing, and the orientation of each drawing corresponds to the direction of the symbols and numbers. In addition, the directions such as parallel, right angle, and vertical are allowed to be misaligned to the extent that the effect is not impaired.

[0010] In the following, various embodiments will be described using as an example a vehicle windshield 1 that is attached to the front of a vehicle. However, the vehicle windshield 1 described below may also be attached to the side or rear of the vehicle.

[0011] [First embodiment] Fig. 1 is a schematic diagram of a vehicle windshield 1 according to a first embodiment. Fig. 2 is an enlarged view of a portion Q1 in Fig. 1. Fig. 3 is a schematic cross-sectional view taken along line AA in Fig. 2. Fig. 3 also shows a cover 4, which is not shown in Figs. 1 and 2. Fig. 3 shows the vehicle exterior side and vehicle interior side (vehicle compartment side) based on the center of the thickness direction of a window glass 50.

[0012] Fig. 1 also shows a vehicle housing 80 to which the vehicle windshield 1 is attached. Fig. 1 is a diagram of the surfaces of a window glass (front glass) 50 viewed from the inside of the vehicle cabin, showing the window glass 50 attached to the vehicle. The window glass 50 can be applied not only to automobiles but also to various other moving bodies, such as trains, buses, ships, aircraft, and construction machinery.

[0013] In the following, each region of the window glass 50 (such as the first region 131) is a region of the surface of the window glass 50 (for example, the surface on the vehicle interior side), but may be a region including a thickness portion of the window glass 50. The distance (or a similar distance) between each region of the window glass 50 is the shortest distance along the surface of the window glass 50, but when the radius of curvature of the window glass 50 is relatively large, it may be the shortest distance on an approximating plane. Here, as shown in FIG. 1, an X direction and a Y direction are defined as two directions perpendicular to each other, and the XY plane is a plane that can approximate the surface of the window glass 50. The X direction corresponds to the vehicle width direction, and the Y direction corresponds to the up-down direction (however, it may be the up-down direction inclined to the vertical direction).

[0014] As shown very diagrammatically in Fig. 1, the vehicle windshield 1 includes a window glass 50, a heating device 60, and a sensor device 70. Note that part of the sensor device 70 (see Fig. 2) is not shown in Fig. 1.

[0015] The window glass 50 is a window plate that covers an opening of the vehicle housing 80. The base material of the window glass 50 is not limited to glass and may be resin, film, or the like, but is assumed to be one that transmits radio waves. The window glass 50 may be formed by bonding together a plurality of base materials, and may be provided with films or the like that realize various functions, or may have an antenna or the like formed thereon. In the present embodiment, as an example, the window glass 50 may be produced by stacking two pieces of glass 51a, 51b with an intermediate film 51c interposed therebetween (see FIG. 3) to produce a polymer, and then pressurizing and heating the produced polymer in an autoclave or the like.

[0016] The window glass 50 is attached to a body flange formed in a vehicle housing 80. In Fig. 1, outer peripheral edges 50a, 50b, 50c, and 50d of the window glass 50 are shown by dashed lines. The vehicle housing 80 has a body flange edge 80 that forms a window opening in the vehicle body.

[0017] The windshield window glass 50 has a shielding region in the peripheral region on the surface. The shielding region is a region where a shielding film 54 is formed in black or brown, or a region where a part of the intermediate film is colored. The shielding film 54 is formed of ceramics such as a black ceramic film or a black organic ink film. The shielding film 54 is intended to improve the design from the outside and the inside of the vehicle when an in-vehicle device is installed, and is made to transmit radio waves. The shielding film 54 has a constant width portion 54a formed with a substantially constant width from the outer periphery of the window glass 50, and a convex portion 54b that is convex downward at the upper and center portion (center portion in the left-right direction) of the window glass 50. The convex portion 54b may be in a form in which the width in the left-right direction becomes smaller toward the bottom (a substantially trapezoidal shape that is symmetrical from left to right), or may be in a form in which the width in the left-right direction becomes larger. The convex portion 54b may have a cut in part.

[0018] The heating device 60 is a device for heating the window glass 50. The heating device 60 includes a first heating device 61 and a second heating device 62.

[0019] The first heating device 61 is provided in correspondence with the first region 131 of the window glass 50 .

[0020] The first region 131 is a part of the entire region of the window glass 50, and is set in correspondence with the forward visibility of the occupants including the driver. The above-mentioned shielding film 54 is provided so as not to affect the forward visibility through the first region 131. The shape of the first region 131 is arbitrary, but may be rectangular in plan view (as viewed perpendicularly to the XY plane, the same applies below) as shown in FIG. 1. However, in a modified example, the shape of the first region 131 may include a concave or convex shape on the outer periphery in plan view.

[0021] The first heating device 61 includes a first heating element 610 , bus bars 612 and 613 , and a switch unit 614 .

[0022] The first heating element 610 is in the form of an electric heating wire or an electric heating film, and has a characteristic of generating heat when an electric current flows through it. For example, as shown in FIG. 3, the first heating element 610 may be provided on the outer surface of the glass 51b on the vehicle interior side of the window glass 50. The first heating element 610 is disposed in the first region 131. In other words, the first heating element 610 is disposed in a manner that defines the first region 131. Here, the boundary of the first region 131 in the Y direction is determined by the first heating element 610. That is, the upper boundary of the first region 131 in the Y direction is the position of the first heating element 610 that is the uppermost in the Y direction, and the lower boundary of the first region 131 in the Y direction is the position of the first heating element 610 that is the lowermost in the Y direction. Moreover, the boundary of the first region 131 in the X direction is defined by a line connecting the end positions (connection positions with the bus bars 612, 613) of each of the first heating elements 610 on each side in the X direction.

[0023] The first heating elements 610 are preferably arranged without substantial bias in arrangement density so as to realize uniform heating in the first region 131. In this embodiment, as an example, a plurality of heating wires, which are the first heating elements 610, extend in the X direction with a constant pitch d1 in the Y direction, as shown in Fig. 1. The first heating elements 610 may be formed in a manner that they are not continuous with each other, but are folded back from one end to the other end in the X direction and then folded back from the other end to one end (a reciprocating manner).

[0024] In this embodiment, as an example, each first heating element 610 extends in the X direction and is arranged in a row in the Y direction, but this is not limited to this. For example, each heating wire constituting the first heating element 610 may extend in the Y direction and be arranged in a row in the X direction.

[0025] The heating wire is made of copper, silver, or tungsten. The heating film is made of dielectric layer / silver / dielectric layer or dielectric layer / silver / dielectric layer / silver / dielectric layer. The dielectric layer is made of tin oxide, zinc oxide, silicon nitride, titanium oxide, or aluminum oxide.

[0026] The bus bar 612 forms, for example, a positive electrode and is electrically connected to the positive electrode side of an in-vehicle battery (not shown). The bus bar 612 may be in the form of, for example, a film of a conductive material. This also applies to other bus bars such as the bus bar 613. The in-vehicle battery may be electrically connected to the bus bar 612 via a power supply generating unit (not shown) that generates a predetermined power supply voltage. The bus bar 612 extends in the Y direction to the left of the X direction of the first region 131, for example, as shown in FIG. 1, in a mode in which the bus bar 612 is located within the constant width portion 54a on the left side in the X direction in a plan view.

[0027] The bus bar 613 forms, for example, a negative electrode, and is electrically connected to the negative electrode (ground) of an in-vehicle battery (not shown). For example, as shown in Fig. 1, the bus bar 613 extends in the Y direction to the right of the X direction of the first region 131 in a mode in which it is located within the constant width portion 54a on the right side in the X direction in a plan view. The bus bar 613 may be symmetrical to the bus bar 612.

[0028] The switch unit 614 is electrically connected between the bus bar 612 and the vehicle battery. The switch unit 614 includes a switch for turning on / off the current supply to the first heating element 610. This type of switch may be in the form of a relay or a semiconductor switch, for example. When the switch unit 614 is controlled to be on, electrical continuity between the first heating element 610 and the vehicle battery (i.e., current is supplied to the first heating element 610) is realized, and the window glass 50 in the first region 131 is heated by the heat generated by the first heating element 610.

[0029] The on / off state of the switch unit 614 is controlled by the control device 10 (see FIG. 4). Although the wiring from the switch unit 614 to the control device 10 is not shown in FIG. 1 etc., it may be formed in a region overlapping the constant width portion 54a in a plan view, similar to the various wirings related to the first heating device 61.

[0030] The second heating device 62 is provided in association with the second region 132 of the window glass 50 .

[0031] The second region 132 is a part of the entire region of the window glass 50, and is set in correspondence with the vehicle periphery monitoring sensor 20 (see the dashed-dotted rectangle in FIG. 3). The vehicle periphery monitoring sensor 20 may be a radar sensor (e.g., a millimeter-wave radar sensor), an image sensor (i.e., a camera, e.g., a stereo camera), or the like. As shown in FIG. 3, the second region 132 is covered by a cover 4 on the passenger compartment side. The cover 4 may have any shape as long as it at least partially covers the second region 132, and may be, for example, a housing. In this case, for example, a radar sensor, an image sensor, a LiDAR (lidar), a board, or the like may be disposed by utilizing the space formed between the second region 132 of the window glass 50 and the cover 4.

[0032] In this way, the second region 132 is set in correspondence with the forward visibility for the "eyes" of the vehicle periphery monitoring sensor 20. Therefore, the convex portion 54b of the shielding film 54 described above may have an opening so as not to affect the forward visibility through the second region 132. However, when the shielding film 54, which transmits radio waves, does not affect the "eyes" of the vehicle periphery monitoring sensor 20, the shielding film 54 may be formed in a manner that overlaps the second region 132 in a plan view.

[0033] The shape of the second region 132 is arbitrary, and may be rectangular in plan view as shown in Fig. 2. However, in a modified example, the shape of the second region 132 may include a concave or convex shape on the outer periphery in plan view.

[0034] The second heating device 62 includes a second heating element 620 , bus bars 622 and 623 , and a switch unit 624 .

[0035] The second heating element 620 is in the form of an electric heating wire or an electric heating film, and has a characteristic of generating heat when an electric current flows through it. For example, as shown in FIG. 3, the second heating element 620 may be provided on the surface of the glass 51b on the vehicle interior side of the window glass 50. The second heating element 620 is disposed in the second region 132. In other words, the second heating element 620 is disposed in a manner that defines the second region 132. Here, the boundary of the second region 132 in the Y direction is determined by the second heating element 620. That is, the upper boundary of the second region 132 in the Y direction is the position of the second heating element 620 that is the uppermost in the Y direction, and the lower boundary of the second region 132 in the Y direction is the position of the second heating element 620 that is the lowermost in the Y direction. Moreover, the boundary of the second region 132 in the X direction is defined by a line connecting the end positions (connection positions with the bus bars 622, 623) of each second heating element 620 on each side in the X direction.

[0036] The second heating elements 620 are preferably arranged so that there is substantially no bias in the arrangement density so that uniform heating is achieved in the second region 132. In this embodiment, as an example, the heating wires of the second heating elements 620 extend in the X direction with a constant pitch d2 in the Y direction as shown in FIG. 2. The pitch d2 may be the same as or different from the pitch d1. When a cover 4 (see FIG. 3) is provided to cover the second region 132 from the passenger compartment side as in this embodiment, the humidity in the second region 132 is likely to be high, so that the pitch d2 may be smaller than the pitch d1 to easily prevent condensation in the second region 132.

[0037] The second heating element 620 preferably has a higher heat density (W / cm 2 ) than the first heating element 610. 2 ) is high. In this case, the glass temperature of the second region 132 can be increased relatively quickly. When a cover 4 (see FIG. 3) is provided to cover the second region 132 from the passenger compartment side as in this embodiment, the humidity in the second region 132 tends to be high. Therefore, by increasing the heat generation density of the second heating element 620, condensation in the second region 132 can be effectively suppressed.

[0038] The heat density of the second heating element 620 is preferably within a range of 1.5 to 6 times that of the first heating element 610, more preferably within a range of 1.8 to 5 times that of the first heating element 610, and most preferably within a range of 2 to 3 times that of the first heating element 610. For example, the heat density of the first heating element 610 is 400 W / cm 2 In this case, the heat density of the second heating element 620 may be, for example, 900 W / cm 2 from 2200W / cm 2 may be in the range.

[0039] In this embodiment, as an example, the second heating elements 620 may be formed in a manner that they are not continuous with each other, but are folded back from one end to the other end in the X direction and then folded back from the other end to the one end (reciprocating). In this embodiment, as an example, the second heating elements 620 extend in the X direction and are arranged in a row in the Y direction, but this is not limited thereto. For example, the heating wires constituting the second heating elements 620 may extend in the Y direction and be arranged in a row in the X direction.

[0040] The bus bar 622 forms, for example, a positive electrode and is electrically connected to the positive electrode of an in-vehicle battery (not shown). The in-vehicle battery may be electrically connected to the bus bar 622 via a power supply generating unit (not shown) that generates a predetermined power supply voltage. The bus bar 622 extends in the Y direction on the left side of the second region 132 in the X direction, for example, as shown in FIG. 2.

[0041] The bus bar 623 forms, for example, a negative electrode, and is electrically connected to the negative electrode (ground) of an in-vehicle battery (not shown). The bus bar 623 extends in the Y direction on the right side of the second region 132 in the X direction, as shown in FIG. 2. The bus bar 623 may be symmetrical to the bus bar 622.

[0042] The switch unit 624 is electrically connected between the bus bar 622 and the vehicle battery. The switch unit 624 includes a switch for turning on / off the current supply to the second heating element 620. This type of switch may be in the form of a relay or a semiconductor switch, for example. When the switch unit 624 is controlled to be on, electrical continuity between the second heating element 620 and the vehicle battery (i.e., current is supplied to the second heating element 620) is realized, and the window glass 50 in the second region 132 is heated by the heat generated by the second heating element 620.

[0043] The on / off state of the switch unit 624 is controlled by the control device 10 (see FIG. 4). Although wiring from the switch unit 624 to the control device 10 is not shown in FIG. 1 etc., it may be formed in a region overlapping the constant width portion 54a and the convex portion 54b in a plan view, similar to the various wirings related to the second heating device 62. Furthermore, the wiring may be realized by using a substrate that can be disposed between the second region 132 of the window glass 50 and the cover 4, without using the region overlapping the constant width portion 54a in a plan view.

[0044] In this embodiment, the first heating element 610 of the first heating device 61 and the second heating element 620 of the second heating device 62 are electrically connected to an on-board battery (not shown) in a parallel relationship with each other. In addition, the switch unit 614 of the first heating device 61 is not located on the wiring between the second heating element 620 and the on-board battery (not shown), and the switch unit 624 of the second heating device 62 is not located on the wiring between the first heating element 610 and the on-board battery (not shown). Therefore, basically, the first heating element 610 and the second heating element 620 can operate independently of each other.

[0045] The sensor device 70 includes a first temperature sensor 71, a second temperature sensor 72, a first humidity sensor 76, and a second humidity sensor 77.

[0046] The first temperature sensor 71 is in the form of, for example, a thermistor, and is provided in correspondence with the first region 131. The first temperature sensor 71 is provided to detect the glass temperature of the first region 131. For this purpose, the first temperature sensor 71 is preferably provided in the first region 131 or in the vicinity of the first region 131. In FIG. 1, the first temperature sensor 71 is provided, as an example, on the left side in the X direction and above in the Y direction of the first region 131, in a mode in which the first temperature sensor 71 is located within the constant width portion 54a on the left side in the X direction in a plan view. Moreover, the first temperature sensor 71 is preferably installed so that a sensing element is in contact with the glass surface.

[0047] The first temperature sensor 71 supplies an electric signal (an example of temperature information) indicating the glass temperature in the first region 131 to the control device 10 (see FIG. 4). Although wiring from the first temperature sensor 71 to the control device 10 is not shown in FIG. 1 etc., it may be formed in a region overlapping the constant width portion 54a in a plan view, similar to various wirings related to the first heating device 61.

[0048] The second temperature sensor 72 is in the form of, for example, a thermistor, and is provided in correspondence with the second region 132. The second temperature sensor 72 is provided to detect the glass temperature of the second region 132. For this purpose, the second temperature sensor 72 is preferably provided in the second region 132 or in the vicinity of the second region 132. In Fig. 2, the second temperature sensor 72 is provided, as an example, on the lower side in the Y direction within the second region 132, in a mode in which it is located within the protrusion 54b in a plan view.

[0049] The second temperature sensor 72 supplies an electric signal (an example of temperature information) indicating the glass temperature of the second region 132 to the control device 10 (see FIG. 4). Note that although wiring from the second temperature sensor 72 to the control device 10 is not shown in FIG. 1 etc., it may be realized in the same manner as the various wirings related to the second heating device 62.

[0050] The first humidity sensor 76 is provided in association with the first region 131. The first humidity sensor 76 is provided to detect the humidity of the air related to the first region 131. For this purpose, the first humidity sensor 76 is preferably provided in the first region 131 or in the vicinity of the first region 131. In FIG. 1, the first humidity sensor 76 is provided, for example, on the left side in the X direction and on the upper side in the Y direction of the first region 131 in a manner to be located within the constant width portion 54a on the left side in the X direction in a plan view. Moreover, the first humidity sensor 76 is preferably installed such that a sensing element (such as a moisture-sensitive material) is located at a position separated from the glass surface by the thickness of the boundary layer.

[0051] In addition, in FIG. 1, the first humidity sensor 76 is separate from the first temperature sensor 71, but the first humidity sensor 76 may be in the form of an IC (Integrated Circuit) in which the first temperature sensor 71 is integrally incorporated.

[0052] The first humidity sensor 76 supplies an electric signal indicating the humidity at the installation position to the control device 10 (see FIG. 4). Note that wiring from the first humidity sensor 76 to the control device 10 may be realized in a similar manner to that of the first temperature sensor 71.

[0053] The second humidity sensor 77 is provided in correspondence with the second region 132. The second humidity sensor 77 is provided to detect the humidity of the air relating to the second region 132. For this purpose, the second humidity sensor 77 is preferably provided in the second region 132 or in the vicinity of the second region 132. In FIG. 2, the second humidity sensor 77 is provided, as an example, in a manner such that it is located within the second region 132 in a plan view. Moreover, the second humidity sensor 77 is preferably installed such that a sensing element (such as a moisture-sensitive material) is located at a position separated from the glass surface by the thickness of the boundary layer.

[0054] In FIG. 2, the second humidity sensor 77 is separate from the second temperature sensor 72, but the second humidity sensor 77 may be in the form of an IC in which the second temperature sensor 72 is integrated.

[0055] The second humidity sensor 77 supplies an electric signal indicating the humidity at the installation position to the control device 10 (see FIG. 4). Note that wiring from the second humidity sensor 77 to the control device 10 may be realized in a similar manner to that of the second temperature sensor 72.

[0056] Next, a control system for the vehicle windshield 1 will be described with reference to FIGS.

[0057] FIG. 4 is a schematic diagram of a control system for the vehicle windshield 1. As shown in FIG.

[0058] The control system for the vehicle windshield 1 includes a control device 10. The control device 10 may be realized as a body ECU (Electronic Control Unit) that controls door locks and the like of the vehicle.

[0059] The control device 10 includes a CPU (Central Processing Unit) 11, a RAM (Random Access Memory) 12, a ROM (Read Only Memory) 13, an auxiliary storage device 14, a drive device 15, and a communication interface 17, all connected by a bus 19, as well as a wired transceiver unit 25 and a wireless transceiver unit 26 connected to the communication interface 17.

[0060] The auxiliary storage device 14 is, for example, a hard disk drive (HDD) or a solid state drive (SSD), and is a storage device that stores data related to application software and the like.

[0061] The wired transceiver 25 includes a transceiver capable of communicating using an in-vehicle network 31 that complies with a protocol such as CAN (Controller Area Network). Various electronic components 3 are connected to the wired transceiver 25 via the in-vehicle network 31.

[0062] In this embodiment, the various electronic components 3 include a brake ECU 32, a wheel speed sensor 33, an air conditioning ECU 34, an outside air temperature sensor 35, an inside air temperature sensor 36, and the like.

[0063] The brake ECU 32 controls a braking device (not shown) of the vehicle based on sensor information from the wheel speed sensor 33, etc. The wheel speed sensor 33 detects a vehicle speed pulse corresponding to the wheel speed. The brake ECU 32 calculates the vehicle speed based on the vehicle speed pulse information from the wheel speed sensor 33, and transmits the vehicle speed information to the in-vehicle network 31. In this case, the control device 10 connected to the in-vehicle network 31 can acquire the vehicle speed information.

[0064] The air conditioning ECU 34 controls the vehicle's air conditioning device based on sensor information from an outside air temperature sensor 35, an inside air temperature sensor 36, etc. The outside air temperature sensor 35 detects the temperature of the air outside the vehicle (outside air temperature). The inside air temperature sensor 36 detects the temperature of the air inside the vehicle cabin (inside air temperature). The air conditioning ECU 34 transmits the outside air temperature information from the outside air temperature sensor 35 and the inside air temperature information from the inside air temperature sensor 36 to the in-vehicle network 31.

[0065] Some of the various electronic components 3 may be electrically connected to the bus 19, or may be connected to the wireless transmitting / receiving unit .

[0066] The wireless transceiver 26 is a transceiver capable of communicating using a wireless network. The wireless network may include a wireless communication network for mobile phones, the Internet, a Virtual Private Network (VPN), a Wide Area Network (WAN), etc. The wireless transceiver 26 may also include a Near Field Communication (NFC) unit, a Bluetooth (registered trademark) communication unit, a Wireless-Fidelity (Wi-Fi) transceiver, an infrared transceiver, etc.

[0067] The control device 10 may be connectable to a recording medium 16. The recording medium 16 stores a predetermined program. The program stored in the recording medium 16 is installed in the auxiliary storage device 14 of the control device 10 via the drive device 15. The installed predetermined program can be executed by the CPU 11 of the control device 10. For example, the recording medium 16 may be a recording medium that records information optically, electrically, or magnetically, such as a CD (Compact Disc)-ROM, a flexible disk, or a magneto-optical disk, or a semiconductor memory that records information electrically, such as a ROM or a flash memory.

[0068] The control device 10 is electrically connected to the first temperature sensor 71, the second temperature sensor 72, the first humidity sensor 76, and the second humidity sensor 77. The control device 10 is also electrically connected to the switch unit 614 and the switch unit 624. Note that in FIG. 4, the switch unit 614 and the switch unit 624 are shown diagrammatically together with the first heating element 610 and the second heating element 620. Note that in FIG. 4, Vcc represents the power supply voltage supplied to the first heating element 610 and the second heating element 620.

[0069] The control device 10 executes various controls. The various controls include control related to the vehicle windshield 1 (hereinafter also referred to as "windshield heating control"). The windshield heating control includes controlling the first heating device 61 and the second heating device 62 based on various sensor information from the first temperature sensor 71, the second temperature sensor 72, the first humidity sensor 76, and the second humidity sensor 77.

[0070] Fig. 5 is a functional diagram showing functions of the control device 10 (heating control system) related to windshield heating control. Fig. 6 is an explanatory diagram of threshold information. Fig. 7 is an explanatory diagram of causes of defects (e.g., cracks) that may occur in the third region 133 (described later).

[0071] 5, the control device 10 (heating control system) includes a sensor information acquisition unit 150, a control information storage unit 151, and a control processing unit 152. The sensor information acquisition unit 150 and the control processing unit 152 can be realized by the above-mentioned CPU 11 executing one or more programs in a storage device (for example, ROM 13). The control information storage unit 151 can be realized by a storage device (for example, ROM 13, auxiliary storage device 14, etc.).

[0072] The sensor information acquisition unit 150 acquires various types of sensor information related to the window glass 50 from the first temperature sensor 71, the second temperature sensor 72, the first humidity sensor 76, and the second humidity sensor 77. The sensor information acquisition unit 150 also acquires vehicle speed information, outside air temperature information, and inside air temperature information (hereinafter, these three pieces of information are also collectively referred to as "environmental information") via the in-vehicle network 31. The sensor information acquisition unit 150 may acquire various types of sensor information at predetermined intervals.

[0073] The control information storage unit 151 stores control information used in the windshield heating control. In this embodiment, the control information includes threshold information for setting a threshold (a threshold Th described later). The details of the threshold information will be described later.

[0074] The control processing unit 152 performs control processing to control the first heating device 61 and the second heating device 62 based on various sensor information acquired by the sensor information acquisition unit 150. Specifically, the control processing unit 152 controls the switch unit 614 to turn on / off based on various sensor information acquired by the sensor information acquisition unit 150, thereby transitioning the state of the first heating element 610 between a conducting state and a non-conducting state. In addition, the control processing unit 152 controls the switch unit 624 to turn on / off based on various sensor information acquired by the sensor information acquisition unit 150, thereby transitioning the state of the second heating element 620 between a conducting state and a non-conducting state.

[0075] As shown in FIG. 5, the control processing unit 152 includes a first current supply processing unit 1521, a second current supply processing unit 1522, a threshold setting processing unit 1523, a temperature difference parameter calculation unit 1524, a threshold determination processing unit 1525, and a temperature difference reduction processing unit 1526.

[0076] The first current supply processing unit 1521 executes a first current supply process to supply current to the first heating element 610 so as to prevent condensation (including fogging) from occurring in the first region 131 based on the sensor information from the first temperature sensor 71 and the first humidity sensor 76.

[0077] For example, the first current supply processing unit 1521 calculates a dew point temperature (hereinafter also referred to as "first dew point temperature") at which condensation begins to occur in the first region 131 based on each sensor information from the first temperature sensor 71 and the first humidity sensor 76. Then, the first current supply processing unit 1521 energizes the first heating element 610 when the glass temperature of the first region 131 based on the sensor information from the first temperature sensor 71 is equal to or lower than a first current supply start threshold corresponding to the first dew point temperature. The first current supply start threshold may be the first dew point temperature or may be a value higher by a certain margin. Furthermore, when the current supply is started in this manner, the first current supply processing unit 1521 stops the current supply to the first heating element 610 when the glass temperature of the first region 131 based on the sensor information from the first temperature sensor 71 becomes equal to or higher than a first current supply end threshold corresponding to the first dew point temperature. The first current supply end threshold may be a value slightly larger than the first dew point temperature. However, in a modified example, the first current supply end threshold may be the same as the first current supply start threshold.

[0078] The second energization processing unit 1522 executes a second energization process for energizing the second heating element 620 based on the sensor information from the second temperature sensor 72 and the second humidity sensor 77 so as to prevent condensation from occurring in the second region 132.

[0079] For example, the second current supply processing unit 1522 calculates a dew point temperature (hereinafter also referred to as "second dew point temperature") at which condensation begins to occur in the second region 132 based on each sensor information from the second temperature sensor 72 and the second humidity sensor 77. Then, the second current supply processing unit 1522 energizes the second heating element 620 when the glass temperature of the second region 132 based on the sensor information from the second temperature sensor 72 becomes equal to or lower than a second current supply start threshold corresponding to the second dew point temperature. The second current supply start threshold may be the second dew point temperature or may be a value higher by a certain margin. Furthermore, when the current supply is started in this manner, the second current supply processing unit 1522 stops the current supply to the second heating element 620 when the glass temperature of the second region 132 based on the sensor information from the second temperature sensor 72 becomes equal to or higher than a second current supply end threshold corresponding to the second dew point temperature. The second current supply end threshold may be a value slightly larger than the second dew point temperature. However, in a modified example, the second current supply end threshold may be the same as the second current supply start threshold.

[0080] The threshold setting processing unit 1523 sets a threshold (hereinafter, referred to as "threshold Th" to distinguish it from other thresholds) based on the environmental information (vehicle speed information, outside air temperature information, and inside air temperature information) acquired by the sensor information acquisition unit 150. The threshold Th may be constant, but in this embodiment, it is a variable value set based on threshold information. When the threshold Th is constant, the threshold information in the control information storage unit 151 and the threshold setting processing unit 1523 are omitted. As described in detail below, the threshold Th is a threshold related to the execution condition of the temperature difference reduction processing by the temperature difference reduction processing unit 1526, and is compared with the value of the temperature difference parameter. An example of a specific method for setting the threshold Th will be described later.

[0081] The temperature difference parameter calculation unit 1524 calculates a value of a temperature difference parameter based on each piece of sensor information from the first temperature sensor 71 and the second temperature sensor 72 acquired by the sensor information acquisition unit 150. The temperature difference parameter is a parameter that indicates the temperature difference between the glass temperature in the third region 133 of the window glass 50 and the glass temperature in the first region 131 or the glass temperature in the second region 132.

[0082] The third region 133 includes a region that does not belong even partially to either the first region 131 or the second region 132 (i.e., where no heating element is provided) and in which a defect (e.g., a crack) may occur in the window glass 50 due to a temperature difference (temperature difference from the higher glass temperature of the first region 131 or the second region 132) caused by the above-mentioned first and second current application processes. Note that the third region 133 is typically a region having a certain amount of area, but may also be a region having a relatively small area.

[0083] In the present embodiment, as an example, the third region 133 is the entire region between the first region 131 and the second region 132 in the Y direction, and is hereinafter referred to as the "third region 133". In a modified example, the third region 133 may be a part of the region between the first region 131 and the second region 132. The region between the first region 131 and the second region 132 in the Y direction may be a set of positions that overlap both the first region 131 and the second region 132 when viewed in the Y direction. In the present embodiment, the boundary position of the third region 133 in the X direction is substantially the same as that of the second region 132 in terms of the position in the X direction.

[0084] Because the third region 133 is located between the first region 131 and the second region 132 and does not have a heating element, the glass temperature in the third region 133 is likely to be significantly lower than the glass temperatures in the first region 131 and the second region 132.

[0085] In the following, unless otherwise specified, the "glass temperature in the third region 133" refers to the minimum value of the glass temperature at each position in the third region 133. In addition, in the following, with respect to the temperature difference between the glass temperature in the third region 133 and each of the glass temperatures in the first region 131 and the second region 132, the glass temperatures in the first region 131 and the second region 132 are each the glass temperatures based on the sensor information from the first temperature sensor 71 and the second temperature sensor 72. In addition, the temperature difference between the glass temperature in the third region 133 and each of the glass temperatures in the first region 131 and the second region 132 refers to the temperature difference from the higher one of the glass temperatures in the first region 131 and the second region 132. This is because a larger temperature difference makes the window glass 50 more likely to have defects (e.g., cracks). Therefore, in the following, when simply referring to “the temperature difference between the third region 133 and the first region 131 or the second region 132,” this refers to the temperature difference between the glass temperature of the third region 133 and the higher glass temperature of the first region 131 or the second region 132.

[0086] In addition, defects (e.g., cracks) of the window glass 50 due to the temperature difference between the regions are more likely to occur as the temperature gradient (see temperature gradient dT / dY in FIG. 7) increases. In FIG. 7, the horizontal axis indicates each position along the line AA in FIG. 2, and the vertical axis indicates the glass temperature, and two examples of the change characteristics of the glass temperature along the line AA in FIG. 2 (characteristics G700 and G702) are shown. In addition, in FIG. 7, the horizontal axis indicates the direction toward the right and the upper side in the Y direction, and the position P1 corresponds to the boundary position between the first region 131 and the third region 133, and the position P2 corresponds to the boundary position between the third region 133 and the second region 132. The characteristic G700 is a characteristic when there is substantially no temperature difference, and the characteristic G702 is an example of a characteristic that causes defects (e.g., cracks) of the window glass 50. In addition, in FIG. 7, ΔT corresponds to the temperature difference between the third region 133 and the first region 131 or the second region 132. In general, when the distance in the Y direction between position P1 and position P2 is the same (that is, when the length in the Y direction of third region 133 is the same), the larger ΔT is, the larger the gradient dT / dY tends to be.

[0087] The temperature difference parameter calculation unit 1524 may calculate the temperature difference parameter value in any manner. In this embodiment, the temperature difference parameter value may be calculated in any manner based on the values ​​of predetermined input parameters including the sensor information from the first temperature sensor 71 and the second temperature sensor 72. For example, it is also possible to use artificial intelligence to input the values ​​of predetermined input parameters and output (generate) the temperature difference parameter value. In the case of artificial intelligence, this can be realized by implementing a convolutional neural network obtained by machine learning. In machine learning, for example, weights of a convolutional neural network that minimizes the error related to the value of the temperature difference parameter are learned using actual data related to the temperature difference. In this case, the predetermined input parameters may be any parameters that affect the temperature difference between the third region 133 and the first region 131 or the second region 132, such as the glass temperature of the first region 131, the glass temperature of the second region 132, the difference between these glass temperatures, the vehicle speed, the outside air temperature, the inside air temperature, etc.

[0088] Furthermore, the temperature difference parameter does not need to be a parameter that directly represents the temperature difference between the third region 133 and the first region 131 or the second region 132, and may be a parameter that indirectly represents the temperature difference. For example, the temperature difference parameter may be a parameter that represents the change gradient of the glass temperature between the third region 133 and the first region 131 or the second region 132 (this is the rate of change of the glass temperature per unit distance, see the temperature gradient dT / dY in FIG. 7 ).

[0089] In the present embodiment, as an example, the temperature difference parameter is the difference between the glass temperatures indicated by the respective pieces of sensor information from the first temperature sensor 71 and the second temperature sensor 72. That is, the temperature difference parameter is the difference between the glass temperatures in the first region 131 and the second region 132. As described above with reference to FIG. 7, the parameter that directly contributes to defects (e.g., cracks) in the window glass 50 is the temperature gradient dT / dY, but the difference between the glass temperatures in the first region 131 and the second region 132 is a parameter that correlates with the temperature gradient dT / dY. That is, the larger the difference between the glass temperatures in the first region 131 and the second region 132, the larger the temperature gradient dT / dY tends to be. However, in a modified example, the value of the temperature difference parameter may be derived by correcting the value of the difference between the glass temperatures in the first region 131 and the second region 132 to a value that more accurately represents the temperature gradient dT / dY.

[0090] The threshold determination processing unit 1525 determines whether the condition for executing the temperature difference reduction processing by the temperature difference reduction processing unit 1526 is satisfied. Specifically, the threshold determination processing unit 1525 determines whether the value of the temperature difference parameter calculated by the temperature difference parameter calculation unit 1524 exceeds the threshold Th set by the threshold setting processing unit 1523. In this case, the condition for executing the temperature difference reduction processing by the temperature difference reduction processing unit 1526 is satisfied when the value of the temperature difference parameter exceeds the threshold Th.

[0091] The temperature difference reduction processing unit 1526 executes the temperature difference reduction process when the execution condition for the temperature difference reduction process is satisfied (i.e., when the value of the temperature difference parameter exceeds the threshold value Th). The temperature difference reduction process is a process for preventing the temperature difference between the glass temperature in the third region 133 and the glass temperature in the first region 131 or the glass temperature in the second region 132 (hereinafter also simply referred to as the "local temperature difference in the window glass 50") from exceeding an upper limit value. Specifically, the temperature difference reduction process is a process for controlling at least one of the first heating element 610 and the second heating element 620 so that the local temperature difference in the window glass 50 does not exceed an upper limit value.

[0092] The upper limit corresponds to a local temperature difference in the window glass 50 when a defect (e.g., a crack) occurs in the third region 133 of the window glass 50. For example, when a local temperature difference in the window glass 50 is within a certain range and a defect (e.g., a crack) occurs in the third region 133 of the window glass 50, the upper limit corresponds to a lower limit of the range.

[0093] For example, when the glass temperature of the first region 131 is significantly lower than the glass temperature of the second region 132, the temperature difference reduction processing unit 1526 may control the first heating element 610 and the second heating element 620 so as to increase the glass temperature of the first region 131 and / or to suppress an increase in the glass temperature of the second region 132. This can reduce the possibility of a defect in the window glass 50 (a defect in the third region 133 of the window glass 50) that may occur due to the glass temperature of the first region 131 being significantly lower than the glass temperature of the second region 132.

[0094] The temperature difference reduction process is performed to reduce local temperature differences in the window glass 50 that occur when either or both of the first and second current-flow processes are performed. As described above, the first and second current-flow processes are performed to prevent condensation from occurring in the first and second regions 131 and 132, respectively, but they are accompanied by an increase in the glass temperature, which tends to increase the local temperature differences in the window glass 50.

[0095] Here, in the case where the cover 4 (see FIG. 3) that covers the second region 132 from the passenger compartment side is provided as in this embodiment, the humidity in the second region 132 is likely to be high as described above, and therefore the second dew point temperature is likely to be higher than the first dew point temperature. Accordingly, at a certain time, the second current supply start threshold and the second current supply end threshold are almost always equal to or higher than the first current supply start threshold and the first current supply end threshold, respectively. For this reason, in a situation where the vehicle surroundings monitoring sensor 20 should function, a state occurs where only the second current supply process is being executed, but a state where only the first current supply process is being executed does not substantially occur. Therefore, in this embodiment, the execution condition of the temperature difference reduction process is basically satisfied in a state where the second current supply process is being executed. That is, the temperature difference reduction process is executed in a state where the second current supply process is being executed so that the glass temperature of the first region 131 increases and / or the increase in the glass temperature of the second region 132 is suppressed.

[0096] For example, the temperature difference reduction process may include starting the energization of the first heating element 610 without the first current application process (i.e., even though the glass temperature of the first region 131 is higher than the first current application start temperature) when the glass temperature of the first region 131 is lower than the glass temperature of the second region 132 out of the first region 131 and the second region 132. In this case, the local temperature difference in the window glass 50 can be reduced by increasing the glass temperature of the first region 131.

[0097] Furthermore, the temperature difference reduction process may include continuing the energization of the first heating element 610 despite the establishment of the end condition of the first power supply process (i.e., despite the glass temperature of the first region 131 being higher than the first power supply end temperature) when the glass temperature of the first region 131 is lower than the glass temperature of the second region 132. In this case, the glass temperature of the first region 131 increases, thereby making it possible to reduce the local temperature difference in the window glass 50.

[0098] As described above, according to this embodiment, when the value of the temperature difference parameter exceeds the threshold value Th while the second current flow process is being performed, the temperature difference reduction process is performed, thereby making it possible to reduce local temperature differences in the window glass 50. This makes it possible to effectively reduce defects (e.g., cracks) in the window glass 50 that may occur due to significant local temperature differences in the window glass 50 while the second current flow process is being performed.

[0099] Next, the effects of this embodiment will be described with reference to FIGS. 8A to 9D.

[0100] 8A to 8D are explanatory diagrams for a case where the temperature difference reduction process is performed under a condition where only the second current application process is performed, and are explanatory diagrams showing an example of the relationship between the glass temperatures of the first region 131 and the second region 132 and the glass temperature of the third region 133. In Figs. 8A to 8D, the horizontal axis represents each position along the line AA in Fig. 2, and the vertical axis represents the glass temperature, and an example of the change characteristic of the glass temperature along the line AA in Fig. 2 (hereinafter simply referred to as "change characteristic") is shown. Note that in Figs. 8A to 8D, the horizontal axis moves toward the right and toward the upper side in the Y direction, and position P1 corresponds to the boundary position between the first region 131 and the third region 133, and position P2 corresponds to the boundary position between the third region 133 and the second region 132.

[0101] 8A to 8D respectively show the change characteristics at different times from t1 to t4.

[0102] Time t1 is an initial state, and corresponds to the time when the glass temperature of second region 132 becomes equal to or lower than the second current application start threshold. In Fig. 8A, at time t1, the glass temperature of second region 132 is higher than the glass temperature of first region 131.

[0103] Time t2 is a time point after time t1, and corresponds to a time point after a certain amount of time has elapsed since the start of the second current-flow process. Thus, at time t2, due to the second current-flow process, the glass temperature in the second region 132 has risen more than the glass temperature in the first region 131, as compared to time t1, and therefore the local temperature difference in the window glass 50 is relatively large.

[0104] In this way, when only the second current application process is being performed, the local temperature difference on the window glass 50 is likely to become relatively large. In Fig. 8B, the value of the temperature difference parameter exceeds the threshold value Th immediately after time t2, and the temperature difference reduction process is started. That is, immediately after time t2, current application to the first heating element 610 is started even though the glass temperature of the first region 131 is equal to or higher than the first current application start temperature.

[0105] Time t3 is a time point after time t2, and corresponds to a time point after a certain amount of time has elapsed since the start of the temperature difference reduction process. As shown in Fig. 8C, the start of the temperature difference reduction process reduces the local temperature difference on the window glass 50. Note that at time t3, the second current application process started at time t1 is still continuing.

[0106] Time t4 is a time point after time t3, and corresponds to the time point when the second current flow process started at time t1 is normally completed (i.e., the time point when the glass temperature of the second region 132 becomes equal to or higher than the second current flow end threshold). At time t4, as shown in FIG. 8D, the second current flow process ends and the temperature difference reduction process started immediately after time t2 also ends (because there is a low possibility that the local temperature difference in the window glass 50 will further increase thereafter). In other words, a steady state is reached. In a modified example, the temperature difference reduction process may be completed before time t4.

[0107] 8C shows a change characteristic 801 in a comparative example in which the temperature difference reduction process is not performed immediately after time t2, in association with the change characteristic (solid line) at time t3. In this comparative example, as shown in the change characteristic 801, the local temperature difference in the window glass 50 further increases. That is, there is a risk of defects (e.g., cracks) occurring in the window glass 50.

[0108] In contrast, according to the present embodiment, as described above, the temperature difference reduction process is executed under a situation where only the second current flow process is being executed (a situation where the execution conditions for the first current flow process are not satisfied), thereby effectively reducing the possibility of defects (e.g., cracks) in the window glass 50.

[0109] 9A to 9D are explanatory diagrams of a case where the temperature difference reduction process is performed under the condition that the first current supply process and the second current supply process are being performed, and similarly to Fig. 8A to Fig. 8D, the change characteristics are shown at different times from time t11 to time t14. Note that, as a preferred example, the second heating element 620 has a higher heat generation density than the first heating element 610, as described above.

[0110] Time t11 is an initial state, and corresponds to the time when the glass temperature of first region 131 becomes equal to or lower than the first current-flow start threshold and the glass temperature of second region 132 becomes equal to or lower than the second current-flow start threshold. In FIG. 9A , at time t11, the glass temperature of second region 132 is higher than the glass temperature of first region 131.

[0111] Time t12 is a time point after time t11, and corresponds to a time point after a certain amount of time has elapsed since the first current flow process and the second current flow process were started. Note that at time t12, the first current flow process and the second current flow process started at time t11 are still continuing.

[0112] At time t12, compared to time t11, the glass temperature in the second region 132 has risen more than the glass temperature in the first region 131 due to the higher heat density of the second heating element 620 than the first heating element 610, and therefore the local temperature difference in the window glass 50 is relatively large.

[0113] In this way, when the second heating element 620 has a higher heat generation density than the first heating element 610, the local temperature difference in the window glass 50 is likely to become relatively large even when both the first and second current supply processes are being performed. In FIG. 9B, the value of the temperature difference parameter exceeds the threshold value Th immediately after time t12, and the condition for performing the temperature difference reduction process is satisfied. Therefore, even if the glass temperature of the first region 131 reaches or exceeds the first current supply end temperature immediately after time t12, the current supply of the first heating element 610 is maintained by the temperature difference reduction process. In FIG. 9B, the glass temperature of the first region 131 reaches or exceeds the first current supply end temperature immediately after time t2 under the condition that the value of the temperature difference parameter exceeds the threshold value Th, and the temperature difference reduction process is started instead of the first current supply process.

[0114] Time point t13 is a time point after time point t12, and corresponds to a time point after a certain amount of time has elapsed since the start of the temperature difference reduction process. As shown in Fig. 9C, the start of the temperature difference reduction process reduces the local temperature difference on the window glass 50. Note that at time point t13, the second current application process started at time point t1 is still continuing.

[0115] Time t14 is a time point after time t13, and corresponds to the time point when the second current flow process started at time t11 is normally completed (i.e., the time point when the glass temperature of the second region 132 becomes equal to or higher than the second current flow end threshold). At time t14, as shown in FIG. 9D, the second current flow process ends and the temperature difference reduction process started immediately after time t12 also ends (because there is a low possibility that the local temperature difference in the window glass 50 will further increase thereafter). In other words, a steady state is reached. In a modified example, the temperature difference reduction process may be completed before time t14.

[0116] 9C shows a change characteristic 901 in a comparative example in which the temperature difference reduction process is not performed immediately after time t2, in association with the change characteristic at time t13 (solid line). In this comparative example, as shown in the change characteristic 901, the local temperature difference in the window glass 50 further increases. That is, there is a risk of defects (e.g., cracks) occurring in the window glass 50.

[0117] In contrast, according to this embodiment, as described above, when the first current flow process and the second current flow process are being executed, the temperature difference reduction process is executed even when the first current flow process is terminated (i.e., the first current flow process is essentially extended), thereby effectively reducing the possibility of defects (e.g., cracks) in the window glass 50.

[0118] In the present embodiment, as described above, the temperature difference parameter is the difference in glass temperature between the first region 131 and the second region 132, and is not a parameter that directly represents the temperature difference between the third region 133 and the first region 131 or the second region 132. In other words, the difference in glass temperature between the first region 131 and the second region 132 correlates with the temperature difference between the third region 133 and the first region 131 or the second region 132, but may not coincide with the temperature difference between the third region 133 and the first region 131 or the second region 132.

[0119] Such a tendency (i.e., a tendency for the difference in the glass temperatures of the first region 131 and the second region 132 to become larger relative to the temperature difference between the third region 133 and the first region 131 or the second region 132) occurs when the distance between the first region 131 and the second region 132 is relatively large. Hereinafter, such a tendency is referred to as "a tendency for the difference to increase as the distance between the first region 131 and the second region 132 increases" or "a tendency for the difference to increase."

[0120] Figures 10A to 10D are diagrams illustrating the tendency for the difference to increase as the distance between first region 131 and second region 132 increases. Figures 10A to 10D are diagrams to be contrasted with the above-mentioned Figures 8A to 8D, and similarly to Figures 8A to 8D, they show the change characteristics when the temperature difference reduction process is executed under a situation in which only the second current application process is executed, and the periods from time t1 to time t4 are as described above.

[0121] 10A to 10D, unlike FIGS. 8A to 8D, show the change characteristics when the distance between first region 131 and second region 132 is relatively large.

[0122] When the distance between the first region 131 and the second region 132 in the Y direction (i.e., the width of the third region 133 in the Y direction) is relatively large, the difference between the glass temperature in the third region 133 and the glass temperature in the first region 131 becomes relatively large, as shown in Figs. 10A to 10D. That is, in the center of the third region 133 in the Y direction (see section CT in Fig. 10D and region 1331 in Fig. 2), the thermal energy from the first heating element 610 and the second heating element 620 is not easily transferred, and the glass temperature is not easily increased. Therefore, as shown in Figs. 10A to 10D, the change characteristic of the third region 133 significantly decreases in the center and then increases as the position changes from the first region 131 side to the second region 132. The tendency for the change characteristic in the center to be minimal increases as the distance between the first region 131 and the second region 132 increases.

[0123] Moreover, this tendency for the change characteristics in the central portion to be minimal depends on the heat transfer coefficient in the third region 133 (for example, the heat transfer coefficient from the first region 131 or the second region 132 to the central portion). Unlike the distance between the first region 131 and the second region 132, this heat transfer coefficient is not constant and changes depending on the temperature of the window glass 50. Therefore, the heat transfer coefficient changes depending on the values ​​of environmental parameters that affect the temperature of the window glass 50 (an example of predetermined information), such as the vehicle speed, the outside air temperature, the inside air temperature, etc. For example, the higher the vehicle speed, the more likely the temperature of the window glass 50 will drop, and therefore the heat transfer coefficient of the third region 133, etc. will tend to decrease.

[0124] Therefore, the value of the temperature difference parameter may be corrected according to the value of the environmental parameter in a manner that takes into account the heat transfer rate. Alternatively or in addition, the threshold value Th may be corrected (changed) according to the value of the environmental parameter in a manner that takes into account the heat transfer rate. In the present embodiment, as an example, the threshold value Th is corrected (changed) according to the value of the environmental parameter.

[0125] Specifically, the threshold setting processing unit 1523 may set the threshold value Th based on the vehicle speed information so that the threshold value Th becomes smaller as the vehicle speed increases. This is because, as described above, the higher the vehicle speed, the easier it is for the temperature of the window glass 50 to decrease, and therefore the heat transfer coefficient to decrease. Similarly, the threshold setting processing unit 1523 may set the threshold value Th based on the outside air temperature information so that the threshold value Th becomes smaller as the outside air temperature decreases. Furthermore, the threshold setting processing unit 1523 may set the threshold value Th based on the inside air temperature information so that the threshold value Th becomes smaller as the inside air temperature decreases. In this way, even if the heat transfer coefficient of the third region 133 changes in response to a change in the value of the environmental parameter, the threshold value Th can be set so that the execution condition for the temperature difference reduction process is satisfied at an appropriate timing.

[0126] For example, in the present embodiment, the threshold setting processing unit 1523 refers to the threshold information in the control information storage unit 151 and sets the threshold Th according to each value (environmental information) of three environmental parameters, namely, vehicle speed, outside temperature, and inside temperature. In this case, the threshold information indicates the relationship between each value of the three environmental parameters, namely, vehicle speed, outside temperature, and inside temperature, and the threshold. In the example shown in FIG. 6, threshold coefficients corresponding to each value of the three parameters, namely, vehicle speed, outside temperature, and inside temperature, are shown. For example, a threshold coefficient α1 is associated with a vehicle speed within a range of 0 to V1 (low speed range), a threshold coefficient α2 is associated with a vehicle speed within a range of V1 to V2 (medium speed range), and so on. Note that the number of these divisions is arbitrary, and finer divisions may be set. In the case of FIG. 6, the threshold setting processing unit 1523 refers to the threshold information and extracts threshold coefficients corresponding to each value of the three environmental parameters, namely, vehicle speed, outside temperature, and inside temperature, based on the environmental information. Then, the threshold setting processor 1523 calculates the threshold Th by multiplying the extracted threshold coefficient by a predetermined reference value for calculating the threshold Th. Note that each threshold coefficient may be adapted so that the threshold Th calculated in this manner becomes a threshold that satisfies the execution condition for the temperature difference reduction process at an appropriate timing.

[0127] In this embodiment, as an example, the threshold information is information indicating threshold coefficients corresponding to the three environmental parameters, vehicle speed, outside air temperature, and inside air temperature, as shown in Fig. 6, but is not limited to this. The threshold information may be map data that defines a threshold Th corresponding to each combination of the three environmental parameters, vehicle speed, outside air temperature, and inside air temperature. In addition, although three environmental parameters are used in this embodiment, only one or two environmental parameters may be used, or four or more environmental parameters may be used.

[0128] However, as described above, as the distance between the first region 131 and the second region 132 increases, the heat from the first heating element 610 and the second heating element 620 is less likely to be transmitted to the center between the first region 131 and the second region 132. When the distance between the first region 131 and the second region 132 is equal to or greater than a predetermined distance, the heat from the first heating element 610 and the second heating element 620 is not substantially transmitted to the center between the first region 131 and the second region 132. In such a case, the above-mentioned temperature difference reduction process does not substantially function. Therefore, in this embodiment, it is desirable that the distance between the first region 131 and the second region 132 is a distance at which the above-mentioned temperature difference reduction process can function. The upper limit distance (i.e., the above-mentioned predetermined distance) for such a distance depends on various characteristic values ​​of the window glass 50, and can be derived by testing, simulation, or the like.

[0129] On the other hand, as the distance between the first region 131 and the second region 132 becomes smaller, heat from the first heating element 610 and the second heating element 620 is more easily transferred to the third region 133, making it less likely that local temperature differences will occur on the window glass 50.

[0130] Therefore, this embodiment is suitable when the distance between the first region 131 and the second region 132 is within a range of 10 mm to 200 mm. In this embodiment, as shown in FIG. 2, the distance between the first region 131 and the second region 132 can be defined by the distance L1 in the Y direction. In other words, when the distance between the first region 131 and the second region 132 is 10 mm or less, a vehicle windshield 1 in which a local temperature difference is unlikely to occur in the window glass 50 can be realized. That is, when the distance between the first region 131 and the second region 132 is 10 mm or less, the tendency that the change characteristics at the center become minimal as described in FIG. 10A to FIG. 10D is unlikely to occur, and a vehicle windshield 1 in which defects (for example, cracks) are unlikely to occur can be realized. The distance between the first region 131 and the second region 132 may be minimized from the viewpoint of ensuring electrical insulation.

[0131] In this case, the window glass 50 preferably has a plane tensile stress of 5 MPa or less in the portion relating to the third region 133. This is because the risk of cracking due to thermal stress is reduced when the residual tensile stress of the original glass is smaller. Furthermore, the window glass 50 preferably has a glass thickness (for example, glass 51b on the passenger compartment side) of 2 mm or less in the portion relating to the third region 133. This is because such thin glass has a relatively small heat capacity and can reduce local temperature differences in the window glass 50. Also, this is because the glass temperature in the third region 133 rises responsively during the above-mentioned temperature difference reduction process.

[0132] Next, an example of the operation of the control device 10 according to this embodiment will be described with reference to the flowcharts in Fig. 11 and subsequent figures. In the following process flow diagrams (flowcharts), the order of processing steps may be changed as long as the relationship between input and output of each step is not lost.

[0133] 11 is a schematic flow chart showing an example of a process executed by the control device 10 according to the present embodiment in relation to windshield heating control. The process shown in FIG. 11 may be repeatedly executed at predetermined intervals, for example, when a start switch (e.g., an ignition switch) of the vehicle is in an on state.

[0134] In step S1, the control device 10 acquires various information necessary for control. The various information necessary for control is as described above in relation to the sensor information acquisition unit 150, and includes various sensor information related to the window glass 50 and environmental information (vehicle speed information, outside temperature information, and inside temperature information).

[0135] In step S2, the control device 10 executes a first heating element control process for controlling the first heating element 610. The first heating element control process includes the first energization process described above in relation to the first energization processing unit 1521, and an example of the first heating element control process will be described later with reference to FIG.

[0136] In step S3, the control device 10 executes a second heating element control process for controlling the second heating element 620. The second heating element control process includes the second energization process described above in relation to the second energization processing unit 1522, and an example of the second heating element control process will be described later with reference to FIG.

[0137] In step S4, the control device 10 judges whether the temperature difference reduction in progress flag F3 is "0". The temperature difference reduction in progress flag F3 is a flag that is set to "1" when the temperature difference reduction process is being executed, and is set to "0" when the temperature difference reduction process is not being executed. If the judgment result is "YES", the process proceeds to step S5, and otherwise the process proceeds to step S6.

[0138] In step S5, the control device 10 determines whether the second energized flag F2 is "1". The second energized flag F2 is a flag that is set to "1" when the second heating element 620 is energized and set to "0" when the second heating element 620 is not energized. If the determination result is "YES", the process proceeds to step S7, otherwise the process for the current cycle ends.

[0139] In step S6, the control device 10 determines whether or not the second energized flag F2 is “0.” If the determination result is “YES,” the process proceeds to step S11, and otherwise the process proceeds to step S7.

[0140] In step S7, the control device 10 calculates the value of a temperature difference parameter based on the various information obtained in step S1. The temperature difference parameter is as described above in relation to the temperature difference parameter calculation unit 1524.

[0141] In step S8, the control device 10 calculates (sets) the threshold value Th based on the various information obtained in step S1 and the threshold value information. The threshold value information is as described above in relation to the control information storage unit 151, and the threshold value Th is as described above in relation to the threshold value setting processing unit 1523.

[0142] In step S9, the control device 10 judges whether or not the value of the temperature difference parameter obtained in step S7 exceeds the threshold value Th obtained in step S8. If the judgment result is "YES", the process proceeds to step S10, and otherwise the process proceeds to step S11.

[0143] In step S10, the control device 10 sets or maintains the temperature difference reducing flag F3 at "1".

[0144] In step S11, the control device 10 resets or maintains the temperature difference reducing flag F3 at "0".

[0145] In step S12, the control device 10 determines whether the first energized flag F1 is "1". The first energized flag F1 is a flag that is set to "1" when the first heating element 610 is energized and set to "0" when the first heating element 610 is not energized. If the determination result is "YES", the processing for the current cycle ends, otherwise the process proceeds to step S13.

[0146] In step S13, the controller 10 sets the first power-on flag F1 to "1." That is, the controller 10 changes the first power-on flag F1 from "0" to "1."

[0147] FIG. 12 is a schematic flowchart showing an example of the first heating element control process (step S2 in FIG. 11).

[0148] In step S20, the control device 10 determines whether or not the first energized flag F1 is “1.” If the determination result is “YES,” the process proceeds to step S21, and otherwise the process proceeds to step S25.

[0149] In step S21, the control device 10 turns on the switch unit 614 to energize the first heating element 610.

[0150] In step S22, the control device 10 calculates the first current supply end threshold based on the various information obtained in step S1. The first current supply end threshold is as described above.

[0151] In step S23, the control device 10 determines whether the glass temperature of the first region 131 based on the various information obtained in step S1 is equal to or higher than the first current application end threshold value obtained in step S22. If the determination result is "YES", the process proceeds to step S24; otherwise, the process for the current cycle ends.

[0152] In step S24, the controller 10 resets the first energized flag F1 to "0".

[0153] In step S25, the control device 10 calculates the first current supply start threshold based on the various information obtained in step S1. The first current supply start threshold is as described above.

[0154] In step S26, the control device 10 determines whether the glass temperature of the first region 131 based on the various information obtained in step S1 is equal to or lower than the first current application start threshold value obtained in step S25. If the determination result is "YES", the process proceeds to step S27; otherwise, the process for the current cycle ends.

[0155] In step S27, the control device 10 sets the first energized flag F1 to "1".

[0156] Fig. 13 is a schematic flow chart showing an example of the second heating element control process (step S3 in Fig. 11). The flow chart of the second heating element control process in Fig. 13 is substantially different from the flow chart of the first heating element control process shown in Fig. 12 only in that "first" in the following description is replaced with "second", and therefore detailed description will be omitted.

[0157] According to the process shown in FIG. 11 to FIG. 13, in a state in which the second current supply processing unit 1522 executes the second current supply processing ("YES" in step S5), if the value of the temperature difference parameter exceeds the threshold value Th ("YES" in step S9), the first current supply flag F1 is changed to "1" even if it is "0" (step S13). In this case, the first heating element 610 is energized (step S21), thereby realizing the temperature difference reduction process. That is, in the process shown in FIG. 11 to FIG. 13, the energization of the first heating element 610 (step S21) caused by changing the first current supply flag F1 to "1" in step S13 is the temperature difference reduction process. Therefore, according to the process shown in FIG. 11 to FIG. 13, in a state in which the second current supply processing unit 1522 executes the second current supply processing, the temperature difference reduction process is realized, thereby effectively reducing the possibility of defects (e.g., cracks) in the window glass 50.

[0158] 11 to 13, the state of the first current-on flag F1 is forcibly changed in step S13 to realize the temperature difference reduction process in step S21, but this is not limited thereto. For example, when the temperature difference reduction flag F3 is "1", the first current-on end threshold calculated in step S22 may be corrected to a larger value to realize the temperature difference reduction process in step S21. Also, when the temperature difference reduction flag F3 is "1", the first current-on start threshold calculated in step S25 may be corrected to a smaller value to realize the temperature difference reduction process in step S21.

[0159] 11 to 13, the temperature difference reduction process is terminated when the value of the temperature difference parameter becomes equal to or less than the threshold value Th ("NO" in step S9) or when the power supply to the second heating element 620 is terminated ("YES" in step S6), but is not limited thereto. The process may be terminated only when either one of these two conditions is satisfied, or another condition may be added.

[0160] [Second embodiment] In the following description of the second embodiment, components that may be similar to those in the first embodiment described above may be given the same reference numerals and descriptions thereof may be omitted. Also, components that are not particularly described may be similar to those in the first embodiment described above.

[0161] FIG. 14 is an enlarged view of a portion of a vehicle windshield 1A according to the second embodiment, which corresponds to the portion Q1 in FIG.

[0162] The vehicle windshield 1A according to the second embodiment differs from the vehicle windshield 1 according to the first embodiment in the position of the first temperature sensor 71. Specifically, in this embodiment, the first temperature sensor 71 is provided in the third region 133 as shown in FIG. 14. That is, the first temperature sensor 71 is provided at a predetermined position away from the first region 131 and the second region 132. The predetermined position is preferably a position in the third region 133 where the temperature difference with the first region 131 or the second region 132 is maximum (i.e., a position related to the glass temperature of the third region 133) or in the vicinity thereof. Typically, the predetermined position is in the center of the third region 133 (see region 1331).

[0163] According to the vehicle windshield 1A of this embodiment, the first temperature sensor 71 disposed in the third region 133 can accurately detect the minimum glass temperature in the third region 133. This makes it possible to accurately detect the temperature difference between the third region 133 and the first region 131 or the second region 132. As a result, the possibility of defects (e.g., cracks) in the window glass 50 can be further effectively reduced.

[0164] In this embodiment, the functions of the control device related to the windshield heating control are not shown, but may be the same as those in the above-described first embodiment. According to this embodiment, the value of the temperature difference parameter calculated by the temperature difference parameter calculation unit 1524 can accurately represent the temperature difference between the third region 133 and the first region 131 or the second region 132, thereby improving the reliability of the control.

[0165] In this embodiment, of the first temperature sensor 71 and the second temperature sensor 72, the first temperature sensor 71 is provided in the third region 133, and therefore the second current application process can be realized with high accuracy by utilizing the second temperature sensor 72. However, in a modified example, the second temperature sensor 72 may be provided in the third region 133, or a new third temperature sensor (not shown) may be provided in the third region 133.

[0166] Although each embodiment has been described above in detail, the present invention is not limited to the specific embodiment, and various modifications and changes are possible within the scope of the claims. In addition, it is also possible to combine all or a plurality of the components of the above-described embodiments.

[0167] For example, in the above-described embodiment, the temperature difference reduction process is executed when the execution condition of the temperature difference reduction process is satisfied in a state in which the second current supply process is being executed, as described above, but is not limited thereto. For example, the temperature difference reduction process may be executed whenever the second current supply process is executed. Also, the temperature difference reduction process may be started at an earlier stage by predicting a change in the value of the temperature difference parameter. For example, in a case where only the second current supply process is started as described above, and it is predicted that the value of the temperature difference parameter will exceed the threshold value Th due to the second current supply process, the first current supply process may be executed before the value of the temperature difference parameter exceeds the threshold value Th.

[0168] This embodiment can also be used as a heating control program for a windshield. That is, the program according to this embodiment is a program for controlling a heating element provided on a glass that separates the interior and exterior of a vehicle, and causes a computer to execute a process of acquiring sensor information from one or more sensors, and a control process of controlling a first heating element provided on a first region of the glass and a second heating element provided on a second region of the glass different from the first region, based on the sensor information. The control process includes a temperature difference reduction process of controlling at least one of the first heating element and the second heating element so that the temperature difference between the glass temperature in a third region between the first region and the second region of the glass and the glass temperature in the first region or the glass temperature in the second region does not exceed an upper limit value.

[0169] This application claims priority based on Japanese Patent Application No. 2020-034766, filed March 2, 2020, the disclosure of which is incorporated herein in its entirety. [Explanation of symbols]

[0170] 1, 1A Vehicle windshield 3. Electronic Components 4 Cover 10 Control device 20 Vehicle Surroundings Monitoring Sensor 31 In-vehicle network 33 Wheel speed sensor 35 Outside air temperature sensor 36 Interior air temperature sensor 50 Window Glass 51a Glass 51b Glass 51c Intermediate film 54 Shielding membrane 54a Constant width section 54b Convex 60 Heating device 61 1st heating device 610 1st heating element 612 Bus Bar 613 Bus Bar 614 Switch section 62 Second heating device 620 Second heating element 622 Bus Bar 623 Bus Bar 624 Switch section 70 Sensor device 71 First temperature sensor 72 Second temperature sensor 76 First Humidity Sensor 77 Second Humidity Sensor 131 First area 132 Second area 133 Third area 150 Sensor information acquisition unit 151 Control information storage unit 152 Control processing section 1521 First current processing section 1522 Second current processing section 1523 Threshold setting processing unit 1524 Temperature difference parameter calculation unit 1525 Threshold judgment processing unit 1526 Temperature difference reduction processing section

Claims

1. A heating control system for controlling a heating element provided on glass separating an interior and exterior of a moving body, comprising: a sensor information acquisition unit that acquires sensor information from one or more sensors; A control processing unit that controls a first heating element provided in a first region of the glass and a second heating element provided in a second region of the glass different from the first region based on the sensor information, The control processing unit includes a temperature difference reduction processing unit that executes a temperature difference reduction process to control at least one of the first heating element and the second heating element so that a temperature difference between a glass temperature in a third region between the first region and the second region of the glass and the glass temperature in the first region or the glass temperature in the second region does not exceed an upper limit value. Heating control system.

2. The heating control system according to claim 1 , wherein the temperature difference reduction processing unit executes the temperature difference reduction process when a value of a parameter representing the temperature difference exceeds a threshold value.

3. the sensor information includes temperature information from two or more temperature sensors provided at two or more locations on the glass; The heating control system according to claim 2 , wherein the control processing section further includes a temperature difference parameter calculation section that calculates a value of the parameter based on the temperature information.

4. the sensor information includes predetermined information that affects a heat transfer rate of the third region; The heating control system according to claim 2 or 3, wherein the control processing unit executes a process of correcting the threshold value or the parameter value in accordance with the predetermined information.

5. The control processing unit: a first current supply processing unit that executes a first current supply process of supplying current to the first heating element based on the sensor information so as to prevent condensation from occurring in the first region; and a second current supply processing unit that performs a second current supply process of supplying current to the second heating element based on the sensor information so as to prevent condensation from occurring in the second region. The heating control system according to claim 1 , wherein the temperature difference reduction process is executed in a state in which the second current application process is executed.

6. The heating control system of claim 5, wherein the temperature difference reduction process includes at least one of starting energization of the first heating element without the first power supply process and continuing energization of the first heating element despite the establishment of an end condition of the first power supply process.

7. 6. The heating control system of claim 5, wherein the temperature difference reduction processing unit starts energizing the first heating element when the glass temperature in the first region is lower than the glass temperature in the second region, even if the glass temperature in the first region is higher than a first power supply start temperature corresponding to a first dew point temperature of the first region.

8. 6. The heating control system of claim 5, wherein the temperature difference reduction processing unit continues energizing the first heating element even if the glass temperature in the first region becomes equal to or higher than a first power supply end threshold corresponding to a first dew point temperature of the first region while the first power supply processing is being performed.

9. 6. The heating control system of claim 5, wherein the temperature difference reduction processing unit continues energizing the first heating element even if the glass temperature in the first region becomes a temperature at which condensation does not occur in the first region while the first power supply process is being performed.

10. 10. The heating control system according to claim 5, wherein the second current supply process is executed so as to achieve a glass temperature in the second region that is higher than a glass temperature in the first region achieved by the first current supply process.

11. The heating control system according to claim 1 , wherein the second heating element has a higher heat density than the first heating element.

12. The heating control system according to claim 1 , wherein the second area is located above the first area and corresponds to an in-vehicle sensor that acquires vehicle surroundings information.

13. 13. A heating control system according to any one of claims 1 to 12, wherein the shortest distance along the surface of the glass between the first area and the second area is in the range of 10 mm to 200 mm.

14. A glass separating an interior and exterior of a moving body, the glass having a first area, a second area located above the first area and associated with an interior sensor that acquires vehicle surroundings information, and a third area between the first area and the second area; a first heating element disposed in the first region; a second heating element disposed in the second region; a first temperature sensor provided in correspondence with at least one of the first region and the second region; a second temperature sensor provided within the third region at a predetermined position away from the first region and the second region.

15. The windshield of claim 14, wherein the predetermined location is located at a center portion of the third region.

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