Heater Control Device

Abstract

To more accurately estimate the temperature of vehicle window glass and control a heater that warms the window glass.SOLUTION: A control ECU 3 that controls a heater 2 provided on a windshield W of a vehicle V, includes: a solar information acquiring part 11 that acquires position information on the sun; an insolation amount information acquiring part 12 that acquires an insolation amount to window glass; a glass temperature estimation part 14 that estimates a rise in temperature of the windshield W caused by sunlight on the basis of the position information on the sun and the insolation amount, and estimates the temperature of the windshield W on the basis of the estimated rise in temperature of the windshield W caused by the sunlight; and a heater control part 15 that controls the heater 2 on the basis of the estimated temperature of the window glass.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a heater control device that controls a heater provided on a window glass of a vehicle. [Background technology]

[0002] For example, a camera that captures an image of the front of the vehicle is provided on the interior side of the windshield of a vehicle. In this case, if the temperature of the windshield falls below the dew point temperature in the vehicle interior, fogging occurs on the inside of the windshield, making it difficult to capture an image with the camera. In order to prevent this fogging, the windshield is heated by a heater so that the temperature does not fall below the dew point temperature in the vehicle interior. Such a device for heating and defrosting the windshield is described in, for example, Patent Document 1. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 10-258703 Summary of the Invention [Problem to be solved by the invention]

[0004] When a vehicle window glass is heated by a heater, it is necessary to estimate the temperature of the window glass more accurately in order to reduce the power consumption of the heater. For example, if a thermometer is placed in contact with the window glass to directly measure the temperature of the window glass, the window glass is likely to crack, making it difficult to install.

[0005] For this reason, the present disclosure describes a heater control device that can more accurately estimate the temperature of a vehicle window glass and control a heater that warms the window glass. [Means for solving the problem]

[0006] One aspect of the present disclosure is a heater control device that controls a heater provided on a window glass of a vehicle, and includes a solar information acquisition unit that acquires information on the position of the sun, a solar radiation information acquisition unit that acquires the amount of solar radiation on the window glass, a glass temperature estimation unit that estimates a temperature rise of the window glass due to sunlight based on the acquired solar position information and solar radiation and estimates the temperature of the window glass based on the estimated temperature rise of the window glass due to sunlight, and a heater control unit that controls the heater based on the estimated window glass temperature.

[0007] This heater control device can estimate the window glass temperature based on the sun's position information and the amount of solar radiation, taking into account the temperature rise of the window glass caused by sunlight. This allows the heater control device to estimate the window glass temperature of the vehicle with higher accuracy, and to control the heater that warms the window glass based on the estimated window glass temperature.

[0008] The heater control device may further include a temperature acquisition unit that acquires the temperature inside the vehicle's cabin, and the glass temperature estimation unit may estimate the temperature of the window glass based on the acquired temperature inside the vehicle cabin and the estimated rise in temperature of the window glass due to sunlight.

[0009] For example, assuming that there is no temperature rise due to sunlight, the temperature of the interior side of the window glass approaches the temperature inside the vehicle cabin. Therefore, the heater control device can use the temperature inside the vehicle cabin as the temperature of the window glass when it is assumed that there is no temperature rise due to sunlight. The heater control device can then more accurately estimate the actual temperature of the window glass taking into account the temperature rise due to sunlight, based on the temperature inside the vehicle cabin (i.e., the temperature of the window glass when there is no temperature rise due to sunlight) and the estimated rise in temperature of the window glass due to sunlight.

[0010] In the heater control device, the heater control unit may perform control to reduce heat generation by the heater when the estimated window glass temperature is higher than an interior dew point temperature in the passenger compartment of the vehicle.

[0011] As described above, the heater control device can estimate the temperature of the window glass with high accuracy, and thereby the heater control device can control the heater based on the highly accurate window glass temperature, thereby reducing the power consumption of the heater when the heater is used to defog the window glass. Effect of the Invention

[0012] According to one aspect of the present disclosure, the temperature of a vehicle window glass can be estimated with higher accuracy, and a heater for warming the window glass can be controlled. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a block diagram illustrating an example of an anti-fogging device according to an embodiment. [Diagram 2] FIG. 2 is a schematic diagram for explaining the vertical angle of the sun with respect to the windshield. [Diagram 3] FIG. 3 is a schematic diagram for explaining the angle of the sun in the left-right direction with respect to the windshield. [Figure 4] FIG. 4 is a flowchart showing a flow of heater control processing performed in the defrosting device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, an exemplary embodiment of an anti-fogging device to which a heater control device according to the present disclosure is applied will be described with reference to the drawings. In each drawing, the same or corresponding elements are denoted by the same reference numerals, and duplicated explanations will be omitted.

[0015] The defrosting device 1 shown in FIG. 1 defrosts the interior side surface of a vehicle window glass. The defrosting device 1 in this embodiment can defrost the interior side surface of the vehicle window glass, taking into consideration the temperature rise of the vehicle window glass caused by sunlight. As an example, the defrosting device 1 defrosts an area located in front of the forward camera 4 on the windshield (window glass) W of the vehicle V, as shown in FIG. 2. In the following description, "up", "down", "front", "rear", "left", and "right" refer to directions based on the vehicle V.

[0016] As shown in Fig. 1, the defrosting device 1 includes a heater 2 and a control ECU (heater control device) 3. The heater 2 is provided on the surface of the windshield W on the interior side of the vehicle V. The heater 2 heats an area of ​​the surface of the windshield W on the interior side of the vehicle that is located in front of a forward camera 4 to perform defrosting and defogging. In this embodiment, the heater 2 generates heat when power is supplied. As the heater 2, various heating elements can be used, such as a silver hot wire, a brass hot wire, a SUS hot wire, and a transparent conductive film.

[0017] The control ECU 3 controls the heater 2. The control ECU 3 is an electronic control unit having a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), etc. In the control ECU 3, for example, various functions are realized by the CPU executing a program recorded in the ROM or the RAM. The control ECU 3 may be composed of multiple electronic units.

[0018] The control ECU 3 functionally includes a solar information acquisition unit 11, a solar radiation amount information acquisition unit 12, a temperature acquisition unit 13, a glass temperature estimation unit 14, and a heater control unit 15.

[0019] The solar information acquisition unit 11 acquires position information of the sun. Here, the solar information acquisition unit 11 acquires, as the solar position information, the height position and lateral position of the sun as seen from the vehicle V. Note that the solar information acquisition unit 11 can acquire the solar position information using various well-known methods.

[0020] For example, the solar information acquisition unit 11 may acquire the position information of the sun based on an image captured by the front camera 4. For example, if the display of an audio device mounted on the vehicle V has a function of acquiring the angle of incidence of sunlight for anti-glare purposes, the solar information acquisition unit 11 may acquire the angle of incidence of sunlight from the audio device. For example, the solar information acquisition unit 11 may acquire the position information of the sun from an external device such as another vehicle. Also, for example, the solar information acquisition unit 11 may estimate the position information of the sun from the area and time in which the vehicle V is traveling, etc.

[0021] The solar radiation information acquisition unit 12 acquires the amount of solar radiation on the windshield W. The solar radiation information acquisition unit 12 can acquire the amount of solar radiation on the windshield W using various well-known methods. For example, the solar radiation information acquisition unit 12 may acquire the amount of solar radiation on the windshield W from a solar radiation sensor mounted on the vehicle V. For example, if the front camera 4 has a function of measuring the amount of solar radiation, the solar radiation information acquisition unit 12 may acquire the amount of solar radiation from the front camera 4. For example, the solar radiation information acquisition unit 12 may acquire the amount of solar radiation from an external device such as another vehicle. In addition, for example, the solar radiation information acquisition unit 12 may estimate the amount of solar radiation from the area and time in which the vehicle V is traveling.

[0022] The temperature acquisition unit 13 acquires the temperature inside the vehicle cabin of the vehicle V. The temperature acquisition unit 13 can acquire the temperature inside the vehicle cabin using various well-known methods. For example, the temperature acquisition unit 13 may acquire the temperature inside the vehicle cabin from a temperature sensor installed in the vehicle cabin. For example, if an air conditioner mounted on the vehicle V has a sensor that measures the temperature inside the vehicle cabin, the temperature acquisition unit 13 may acquire the temperature inside the vehicle cabin from the air conditioner.

[0023] The glass temperature estimation unit 14 estimates the temperature rise of the windshield W caused by sunlight, based on the sun's position information acquired by the sun information acquisition unit 11 and the amount of sunlight acquired by the sunlight information acquisition unit 12. The temperature rise here refers to the temperature of the windshield W heated by sunlight. The glass temperature estimation unit 14 then estimates the temperature of the windshield W based on the estimated temperature rise of the window glass caused by sunlight and the temperature inside the vehicle compartment acquired by the temperature acquisition unit 13.

[0024] Here, a detailed description will be given of a method for estimating the temperature of the windshield W performed by the glass temperature estimation unit 14. First, the glass temperature estimation unit 14 calculates the vertical angle and the horizontal angle of the sun with respect to the surface (glass surface) of the windshield W of the vehicle V, based on the position information of the sun acquired by the sun information acquisition unit 11.

[0025] As an example, it is assumed that the position information of the sun is acquired based on an image captured by the front camera 4. It is also assumed that the height position of the sun included in the position information of the sun includes the angle φ of the sun S in the height direction relative to the horizon L when viewed from the front camera 4, as shown in Fig. 2. In this case, the glass temperature estimation unit 14 can calculate the angle α of the sun S in the vertical direction relative to the windshield W based on the angle φ of the sun S in the height direction and the inclination angle γ of the windshield W relative to the horizon L, using the following formula (1). α = φ + γ (1) The inclination angle γ of the windshield W is a fixed value for each vehicle, and is set in advance in the windshield temperature estimating unit 14 .

[0026] In addition, the glass temperature estimation unit 14 calculates the left-right angle β of the sun S with respect to the surface of the windshield W, as shown in Figure 3, based on the lateral position of the sun (the lateral position as seen from the front camera 4) included in the sun's position information.

[0027] That is, the glass temperature estimation unit 14 calculates the angle α, which is the vertical incidence angle of the sunlight on the windshield W, and the angle β, which is the horizontal incidence angle of the sunlight on the windshield W, based on the sun's position information.

[0028] Next, the glass temperature estimation unit 14 calculates the amount of heat P received by the windshield W from the sun. Here, as an example, the glass temperature estimation unit 14 can calculate the amount of heat P based on the calculated angles α and β and the amount of solar radiation acquired by the solar radiation information acquisition unit 12, using the following formula (2). P=solar radiation×sinα×sinβ (2)

[0029] Furthermore, the glass temperature estimation unit 14 estimates the temperature rise of the windshield W caused by sunlight, based on the calculated heat amount P and the glass thermal conductivity of the windshield W. Here, the glass temperature estimation unit 14 can estimate the temperature rise of the windshield W caused by sunlight, using the heat amount P and the glass thermal conductivity, based on a well-known calculation method.

[0030] Finally, the glass temperature estimation unit 14 estimates the temperature of the windshield W based on the temperature inside the vehicle compartment acquired by the temperature acquisition unit 13 and the temperature rise of the windshield W caused by sunlight, using the following equation (3). Temperature of the windshield W = Temperature inside the vehicle + Rise in temperature (3)

[0031] Here, for example, if it is assumed that there is no temperature rise of the windshield W due to sunlight, the temperature of the interior side of the windshield W approaches the temperature inside the vehicle cabin. Therefore, the glass temperature estimation unit 14 can use the temperature inside the vehicle cabin as the temperature of the windshield W when it is assumed that there is no temperature rise due to sunlight. Then, by adding up the temperature inside the vehicle cabin and the estimated rise in temperature of the window glass due to sunlight, the glass temperature estimation unit 14 can more accurately estimate the actual temperature of the windshield W (the temperature inside the vehicle cabin of the windshield W) taking into account the temperature rise due to sunlight.

[0032] The heater control unit 15 controls the heater 2 based on the temperature of the windshield W estimated by the glass temperature estimation unit 14. Here, when the temperature of the windshield W estimated by the glass temperature estimation unit 14 is higher than the interior dew point temperature in the passenger compartment of the vehicle V, the heater control unit 15 performs control to reduce the heat generation of the heater 2. The reduction control here includes lowering the output of the heater 2 and stopping the heat generation of the heater 2. The heater control unit 15 can estimate the interior dew point temperature by various methods based on the temperature and humidity in the passenger compartment.

[0033] Furthermore, when the temperature of the windshield W estimated by the glass temperature estimation unit 14 is equal to or lower than the interior dew point temperature in the passenger compartment of the vehicle V, the heater control unit 15 performs normal control of the heater 2 to prevent fogging of the windshield W. As the normal control of the heater 2 here, well-known control for defrosting that is performed based on the estimated temperature of the windshield W, etc., can be performed.

[0034] Next, the flow of processing for controlling the heater 2 in the defrosting device 1 will be described with reference to the flowchart of Fig. 4. Note that the processing shown in Fig. 4 is restarted from the start after a predetermined time has elapsed since the processing ended.

[0035] As shown in Fig. 4, the temperature acquisition unit 13 acquires the temperature inside the vehicle V (S101). The sun information acquisition unit 11 acquires the position information of the sun (S102). The solar radiation amount information acquisition unit 12 acquires the amount of solar radiation on the windshield W (S103). Note that the order of the processes from S101 to S103 shown in Fig. 4 is an example, and the processes are not limited to being performed in this order.

[0036] Next, the glass temperature estimation unit 14 estimates the temperature rise of the windshield W caused by sunlight, based on the sun's position information acquired by the sun information acquisition unit 11 and the amount of sunlight acquired by the sunlight information acquisition unit 12. Then, the glass temperature estimation unit 14 estimates the temperature of the windshield W based on the estimated temperature rise of the window glass caused by sunlight and the temperature inside the vehicle compartment acquired by the temperature acquisition unit 13 (S104).

[0037] The heater control unit 15 determines whether or not the estimated temperature of the windshield W is higher than the interior dew point temperature in the passenger compartment of the vehicle V (S105). If the temperature of the windshield W is higher than the interior dew point temperature (S105: YES), the heater control unit 15 performs control to suppress the output of the heater 2 (S106). On the other hand, if the temperature of the windshield W is equal to or lower than the interior dew point temperature (S105: NO), the heater control unit 15 performs normal control of the heater 2 (S107).

[0038] As described above, the defrosting device 1 can estimate the temperature of the windshield W based on the position information of the sun and the amount of solar radiation, taking into account the temperature rise of the windshield W caused by sunlight. This allows the defrosting device 1 to estimate the temperature of the windshield W of the vehicle V with higher accuracy, and can control the heater 2 that warms the windshield W based on the estimated temperature of the windshield W.

[0039] The glass temperature estimation unit 14 estimates the temperature of the windshield W based on the temperature inside the vehicle cabin and the estimated temperature rise of the windshield W caused by sunlight. For example, if it is assumed that there is no temperature rise caused by sunlight, the temperature of the interior side of the windshield W approaches the temperature inside the vehicle cabin. Therefore, the glass temperature estimation unit 14 can use the temperature inside the vehicle cabin as the temperature of the windshield W when it is assumed that there is no temperature rise caused by sunlight. Then, the glass temperature estimation unit 14 can more accurately estimate the actual temperature of the windshield W taking into account the temperature rise due to sunlight, based on the temperature inside the vehicle cabin (i.e., the temperature of the windshield W when there is no temperature rise caused by sunlight) and the estimated temperature rise of the windshield W caused by sunlight.

[0040] When the estimated temperature of the windshield W is higher than the interior dew point temperature in the vehicle cabin, the heater control unit 15 performs control to reduce heat generation by the heater 2. As described above, the defrosting device 1 can accurately estimate the temperature of the windshield W. As a result, the defrosting device 1 controls the heater 2 based on the highly accurate temperature of the windshield W, thereby making it possible to reduce the power consumption of the heater 2 when the windshield W is defrosted by the heater 2.

[0041] Although the embodiment of the present disclosure has been described above, the present invention is not limited to the above embodiment. For example, the defrosting device 1 is described as defrosting the windshield W, but it can be used to defrost windows other than the windshield W.

[0042] In the above, it has been described that the position information of the sun can be obtained based on the image captured by the front camera 4. In this case, for example, when the position information of the sun cannot be obtained from the captured image, the glass temperature estimation unit 14 may calculate the temperature of the windshield W by assuming that there is no temperature rise of the windshield W due to sunlight. [Explanation of symbols]

[0043] 1...anti-fogging device, 2...heater, 3...control ECU (heater control device), 4...forward camera, 11...sun information acquisition unit, 12...solar radiation information acquisition unit, 13...temperature acquisition unit, 14...glass temperature estimation unit, 15...heater control unit, V...vehicle, W...windshield (window glass).

Claims

1. A heater control device that controls a heater provided on a window glass of a vehicle, a solar information acquisition unit for acquiring solar position information; a solar radiation amount information acquisition unit that acquires the amount of solar radiation on the window glass; a glass temperature estimation unit that estimates a temperature rise of the window glass caused by sunlight based on the acquired solar position information and the solar radiation amount, and estimates a temperature of the window glass based on the estimated temperature rise of the window glass caused by sunlight; a heater control unit that controls the heater based on the estimated temperature of the window glass; A heater control device comprising:

2. A temperature acquisition unit that acquires a temperature inside the vehicle, 2 . The heater control device according to claim 1 , wherein the glass temperature estimating unit estimates the temperature of the window glass based on the acquired temperature inside the vehicle cabin and the estimated increase in temperature of the window glass caused by sunlight.

3. 3 . The heater control device according to claim 1 , wherein the heater control unit performs control to reduce heat generation by the heater when the estimated temperature of the window glass is higher than an interior dew point temperature in a passenger compartment of the vehicle.

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