Vehicle state quantity detection device

Abstract

To accurately detect a state quantity in the vicinity of a surface on a cabin side of a front window in a vehicle state quantity detection device.SOLUTION: A vehicle state quantity detection device 20 includes: an optical fiber 21 that is attached to a surface on a cabin side of a front window 11, and passes through an upper portion and a lower portion of the front window; and a detector 25 that is connected to the optical fiber and detects temperature and humidity in the vicinity of the surface of the front window by measuring reflected light of light incident on the optical fiber. The optical fiber includes a first protruding portion 22 and a second protruding portion 23 that are provided respectively at the upper portion and the lower portion of the front window and extend toward the cabin side. The second protruding portion is formed to have a longitudinal length shorter than that of the first protruding portion. The detector is configured to detect the temperature and the humidity by measuring reflected light generated in the first and second protruding portions, and to set a larger number of measurement points for reflected light in the second protruding portion than measurement points for reflected light in the first protruding portion.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a vehicle state quantity detection device for detecting a state quantity inside a vehicle cabin. [Background technology]

[0002] Typical vehicles are equipped with a defroster system to eliminate fogging caused by condensation on the windshield (glass). The defroster system defogs the windshield by blowing conditioned air from an air outlet onto the surface of the windshield. In recent years, there has been a demand to minimize the energy consumption of such defroster systems in order to improve vehicle fuel efficiency and power consumption.

[0003] Fogging of the windshield depends on state variables (specifically, temperature and humidity) near the surface. The temperature and humidity near the surface of the windshield change depending on the ambient environment, such as the selection of internal air circulation or external air introduction by the vehicle cabin air conditioning system, the number of occupants, and the outside temperature. They also vary significantly on the order of several millimeters to several centimeters in the direction along the surface of the windshield (hereinafter referred to as the "in-plane direction") and in the direction perpendicular to the surface of the windshield (hereinafter referred to as the "out-of-plane direction"). Therefore, in order to prevent fogging of the windshield while reducing the energy consumption of the defroster system, it is desirable to accurately grasp the temperature and humidity near the surface of the windshield and then operate the defroster system appropriately.

[0004] Electric humidity sensors have been known for some time. Electric humidity sensors measure humidity at only one location, so in order to detect the humidity distribution across the entire windshield, multiple sensors must be attached to the windshield surface. Because electric humidity sensors are relatively large, attaching multiple sensors to the windshield surface disrupts the environment near the windshield surface (e.g., the airflow from an air conditioning system). Furthermore, in order to detect the humidity distribution in the out-of-plane direction of the windshield, the electric humidity sensors must be positioned away from the surface, but arranging humidity sensors in this manner is not easy.

[0005] Therefore, in consideration of the problems with electrical humidity sensors as described above, the present inventors have proposed a technology using a humidity sensor that utilizes optical fiber (hereinafter referred to as an "optical fiber sensor" as appropriate) (see Patent Document 1). This optical fiber sensor applies a moisture-absorbing material that expands or contracts in response to humidity changes to an optical fiber having an FBG (Fiber Bragg Grating). In this case, the optical fiber is distorted by the expansion or contraction of the moisture-absorbing material, which changes the wavelength of the light reflected by the FBG. Therefore, the optical fiber sensor can detect humidity based on the wavelength of the reflected light. Unlike electrical humidity sensors, this optical fiber sensor can measure humidity changes at various locations along its length, making it possible to detect humidity over a relatively wide area on the windshield.

[0006] In particular, the technology described in Patent Document 1 uses an optical fiber sensor such as the one described above to detect the humidity distribution in the out-of-plane direction of the windshield and controls the defroster system based on this humidity distribution, thereby preventing fogging of the windshield while reducing the energy consumption of the defroster system. Specifically, this technology detects the humidity distribution in the out-of-plane direction using an optical fiber that has a waveform that curves at a predetermined cycle in the longitudinal direction and that is in contact with and separates from the surface of the windshield. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 2023-32547 Summary of the Invention [Problem to be solved by the invention]

[0008] As a result of further intensive research, the present inventors discovered that the thickness of the air layer that contributes to condensation on the passenger compartment side surface of the windshield (hereinafter simply referred to as the "condensation air layer") is not uniform due to the influence of factors such as wind from the defroster system, i.e., the thickness of the condensation air layer varies in various directions along the in-plane direction of the windshield. Therefore, the state quantities (temperature and humidity) near the surface of the windshield also vary in various ways depending on the thickness of the condensation air layer that varies along the in-plane direction of the windshield. The technology described in the above-mentioned Patent Document 1 did not take into account the change in the thickness of the condensation air layer along the in-plane direction of the windshield, and therefore there was room for improvement in the accuracy of detecting the state quantities near the surface of the windshield.

[0009] The present invention has been made to solve the above-mentioned problems of the conventional technology, and an object of the present invention is to accurately detect state quantities near the surface of the front windshield facing the passenger compartment in a vehicle state quantity detection device using optical fibers. [Means for solving the problem]

[0010] In order to achieve the above object, the present invention provides a vehicle state quantity detection device for detecting state quantities within a vehicle cabin, comprising: an optical fiber attached to the surface of the vehicle's front window so as to extend along the surface facing the passenger compartment, and arranged to pass through at least the upper part (upper half part) and lower part (lower half part) of the front window; and a detector connected to the optical fiber and configured to detect state quantities near the surface of the front window by measuring reflected light of light incident on the optical fiber, wherein the optical fiber includes a first protrusion provided at the upper part of the front window and protruding so as to extend from the surface of the front window toward the passenger compartment, and a second protrusion provided at the lower part of the front window and protruding so as to extend from the surface of the front window toward the passenger compartment, the second protrusion having a shorter longitudinal length than the first protrusion, and the detector detects the state quantities by measuring reflected light generated at the first and second protrusions, and is configured to set more measurement points for reflected light at the second protrusion than for reflected light at the first protrusion.

[0011] In the present invention configured as described above, the longitudinal lengths of the first and second protrusions formed on the optical fiber are set in consideration of the characteristic that the air layer (condensation air layer) that contributes to condensation on the surface of the windshield becomes thinner as it moves downward on the windshield (in other words, thicker as it moves upward) due to the influence of wind from the defroster system. Specifically, the longitudinal length of the second protrusion located at the bottom is shortened in accordance with the thickness of the condensation air layer, which becomes thinner at the bottom of the windshield, and the longitudinal length of the first protrusion located at the top is lengthened in accordance with the thickness of the condensation air layer, which becomes thicker at the top of the windshield. As a result, according to the present invention, the first and second protrusions formed on the optical fiber can accurately detect state quantities of the condensation air layer at different positions in the in-plane direction. In this case, it is possible to prevent the occurrence of areas within the condensation air layer where state quantities are not detected or the detection of state quantities outside the condensation air layer.

[0012] Furthermore, in the present invention, the number of measurement points set on the second protrusion is greater than the number of measurement points set on the first protrusion. As a result, according to the present invention, the large number of measurement points set on the second protrusion ensures high detection accuracy of the state quantity for the thin condensation air layer that occurs below the windshield and whose thickness is prone to fluctuate.

[0013] In the present invention, the second protrusion is preferably formed in a spiral shape. According to the present invention configured in this manner, the overall length of the second protruding portion can be made long, and it becomes possible to accurately set a large number of measurement points on the second protruding portion.

[0014] In the present invention, the first protrusion is preferably formed in a spiral shape. According to the present invention configured in this manner, the overall length of the first protruding portion can be increased, and a large number of measurement points can be accurately set on the first protruding portion.

[0015] In the present invention, the second protruding portion preferably has a greater number of turns in the spiral shape than the first protruding portion. According to the present invention configured in this manner, the overall length of the second protrusion can be made long, making it possible to reliably set more measurement points on the second protrusion than on the first protrusion.

[0016] In the present invention, preferably, the vehicle further includes a support that is attached to the surface of the front window and to which the second protrusion is fixed. According to the present invention configured in this manner, it is possible to prevent the second protrusion from being moved by wind from the defroster system.

[0017] In the present invention, preferably, the vehicle further includes a support that is attached to the surface of the front window and to which the first protrusion is fixed. According to the present invention configured in this manner, it is possible to prevent the first protrusion from being moved by wind from the defroster system.

[0018] In the present invention, the end portion of the first protrusion on the vehicle rear side is preferably located on the vehicle front side of a rearview mirror of the vehicle. According to the present invention configured in this manner, it is possible to prevent the first protrusion from blocking the driver's field of vision.

[0019] In the present invention, preferably, a plurality of the first protruding portions and / or a plurality of the second protruding portions are provided along the vehicle width direction. According to the present invention configured as described above, it is possible to detect state quantities in the vicinity of the surface over a wide range on the front windshield.

[0020] In a preferred example of the present invention, the state quantity is the temperature and / or humidity in the vicinity of the surface of the windshield. [Effects of the Invention]

[0021] According to the present invention, in a vehicle state quantity detection device using optical fibers, it is possible to accurately detect state quantities near the surface of the front windshield facing the passenger compartment. [Brief explanation of the drawings]

[0022] [Figure 1] 1 is a schematic diagram showing the interior of a vehicle to which a vehicle state quantity detection device according to an embodiment of the present invention is applied; [Figure 2] 1 is a block diagram illustrating a vehicle air conditioning control system to which a vehicle state quantity detection device according to an embodiment of the present invention is applied; [Figure 3] 1 is a block diagram illustrating a detector of a vehicle state quantity detection device according to an embodiment of the present invention; [Figure 4] FIG. 1 is a schematic diagram showing temperature changes from the outside of the vehicle to the inside of the vehicle across the front window. [Figure 5] FIG. 10 is a diagram showing the change in thickness of the condensation air layer in the in-plane direction (vertical direction) of the front windshield. [Figure 6] 2A and 2B are diagrams illustrating first and second protrusions of an optical fiber according to an embodiment of the present invention. [Figure 7]10A and 10B are diagrams showing first and second protrusions according to a first modified example of the embodiment of the present invention. [Figure 8] 10A and 10B are diagrams showing first and second protrusions according to a second modification of the embodiment of the present invention. [Figure 9] 10A and 10B are diagrams showing first and second protrusions according to a third modified example of the embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0023] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A vehicle state quantity detection device according to an embodiment of the present invention will now be described with reference to the accompanying drawings.

[0024] [Configuration of vehicle state quantity detection device] First, the configuration of a vehicle state quantity detection device according to this embodiment will be described with reference to Figures 1 to 3. Figure 1 is a schematic diagram showing the interior of a vehicle to which a vehicle state quantity detection device according to this embodiment is applied. Figure 2 is a block diagram showing an air conditioning control system for a vehicle to which a vehicle state quantity detection device according to this embodiment is applied. Figure 3 is a block diagram showing a detector of the vehicle state quantity detection device according to this embodiment.

[0025] As shown in FIG. 1 , a vehicle state quantity detection device 20 according to this embodiment has first and second optical fibers 21a and 21b attached so as to extend along the surface of the vehicle's windshield 11 facing the passenger compartment, and detects state quantities, particularly temperature and humidity, near the surface of the windshield 11 using these first and second optical fibers 21a and 21b. The first optical fiber 21a is an optical fiber for detecting humidity, and the second optical fiber 21b is an optical fiber for detecting temperature. Hereinafter, when there is no need to distinguish between the first and second optical fibers 21a and 21b, they will be referred to as "optical fibers 21." Furthermore, in this specification, the lateral direction (vehicle width direction) and vertical direction (approximately vehicle height direction) defined in the in-plane directions along the surface of the windshield 11 will be referred to as "X" and "Y," respectively, and the out-of-plane direction perpendicular to the surface of the windshield 11 will be referred to as "Z."

[0026] Such a vehicle state quantity detection device 20 is applied to a vehicle air conditioning control system 100, as shown in FIG. 2. In the vehicle air conditioning control system 100, an air conditioning controller 50 controls a defroster system 30 based on the temperature and humidity detected by the vehicle state quantity detection device 20 to defog the windshield 11. Specifically, the defroster system 30 has an air outlet 31 that opens upward on the top surface of the instrument panel 13, and conditioned air is blown out from the air outlet 31 toward the surface of the windshield 11 (FIG. 1). The vehicle air conditioning control system 100 also has an interface 40 that is an operation unit operated by a vehicle occupant. The interface 40 is provided on the instrument panel 13, and the occupant can switch the defroster system 30 on and off via the interface 40.

[0027] Next, the configuration of the vehicle state quantity detection device 20 will be described in more detail. As shown in Fig. 1, the first and second optical fibers 21a, 21b (optical fibers 21) of the vehicle state quantity detection device 20 each consist of a single optical fiber, and are attached to the surface of the windshield 11 facing the passenger compartment so as to extend along the surface. Specifically, the optical fiber 21 extends in the horizontal direction X at the upper part (near the upper end) and lower part (near the lower end) of the windshield 11, and also extends in the vertical direction Y near one side end of the windshield 11. As a result, the optical fiber 21 extends in a U-shape in the in-plane direction of the windshield 11.

[0028] Furthermore, the first and second optical fibers 21a, 21b each include a first protrusion 22a, 22b that is provided in the upper portion (near the upper end) of the windshield 11 and protrudes from the surface of the windshield 11 toward the vehicle interior, and a second protrusion 23a, 23b that is provided in the lower portion (near the lower end) of the windshield 11 and protrudes from the surface of the windshield 11 toward the vehicle interior (for ease of explanation, the first protrusions 22a, 22b and the second protrusions 23a, 23b are shown in a simplified form in FIG. 1). Hereinafter, when the first protrusions 22a, 22b are used without distinction, they will be referred to as a "first protrusion 22," and when the second protrusions 23a, 23b are used without distinction, they will be referred to as a "second protrusion 23."

[0029] A plurality of the first and second protrusions 22, 23 are provided along the lateral direction X (vehicle width direction). Specifically, the first and second protrusions 22, 23 are provided at three positions, respectively, at a left position, a central position, and a right position in the lateral direction X. In this embodiment, the vehicle state quantity detection device 20 uses the first and second protrusions 22, 23 formed on such optical fiber 21 as measurement points for detecting the temperature and humidity near the surface of the front windshield 11 (detailed configurations of the first and second protrusions 22, 23 will be described later). Note that the first and second protrusions 22, 23 may each be provided in two or less or four or more, or the number of first protrusions 22 and second protrusions 23 may not be the same but may be different.

[0030] 2, in the vehicle state quantity detection device 20, the detector 25 is configured to detect humidity using the first optical fiber 21a and detect temperature using the second optical fiber 21b. Here, the optical fiber 21 is typically distorted by temperature changes. Therefore, the detector 25 detects the temperature near the surface of the windshield 11 based on the distortion of the second optical fiber 21b used for temperature detection due to temperature changes. On the other hand, the optical fiber 21 is typically not distorted by humidity changes. Therefore, in this embodiment, the first optical fiber 21a used for humidity detection is covered with a moisture-absorbing material that expands or contracts due to humidity changes. As a result, the detector 25 detects humidity near the surface of the windshield 11 based on the distortion of the first optical fiber 21a due to the expansion or contraction of the moisture-absorbing material. The detector 25 is configured to include a computer having one or more processors (typically a CPU) and memories such as a ROM and a RAM that store various programs interpreted and executed by the processor and various data.

[0031] For example, the vehicle state quantity detection device 20 is configured as a sensing system using Rayleigh scattered light. In this case, as shown in FIG. 3 , the detector 25 of the vehicle state quantity detection device 20 has a laser light source 250, a first spectrometer 251, a second spectrometer 252, a third spectrometer 253, and a measuring device 254. The laser light source 250 is a tunable laser light source and outputs light whose wavelength changes periodically to an optical path. The first spectrometer 251 on the optical path splits the light from the laser light source 250 into measurement light that is directed toward the optical fiber 21 for sensing and reference light that is directed directly to the measuring device 254. The measurement light that is incident on the optical fiber 21 generates scattered light in the optical fiber 21. The scattered light becomes reflected light from the optical fiber 21.

[0032] A second spectrometer 252 on the optical path changes the direction of the reflected light toward a measuring instrument 254. A third spectrometer 253 merges the reference light and the reflected light. The measuring instrument 254 measures a change in light intensity due to interference between the reference light and the reflected light, and measures the scattered light frequency at each measurement point of the optical fiber 21 (a plurality of measurement points set on each of the first and second protrusions 22 and 23 as the measurement locations) from the change in light intensity. The measuring instrument 254 then compares the measured scattered light frequency with a specific frequency associated with unique fingerprint information previously measured for the optical fiber 21 (i.e., information on minute density variations in glass molecules at each measurement point of the optical fiber 21, which differs from one strand of the optical fiber 21 to another), and measures the amount of strain at each measurement point of the optical fiber 21 from the difference between these frequencies (i.e., the amount of shift between the specific frequency and the measured frequency).

[0033] Here, an overview of the temperature and humidity detection process performed by the detector 25 of the vehicle state quantity detection device 20 will be described. First, the detector 25 acquires a reference temperature from a temperature sensor 26 (FIG. 2) provided in the vehicle interior so as to be able to detect the temperature of the windshield 11 and the temperature inside the vehicle interior. For example, the temperature sensor 26 is configured with a thermocouple. Then, the detector 25 measures the amount of distortion at each measurement point (a plurality of measurement points set on each of the first and second protrusions 22b and 23b) set on the second optical fiber 21b using the method described above with reference to FIG. 3, and calculates the temperature change at each measurement point based on this amount of distortion. Then, the detector 25 calculates (detects) the temperature at each measurement point by applying this temperature change to the reference temperature. Note that the detector 25 calculates the temperature using the reference temperature in this way when performing the temperature detection process for the first time, but after the temperature has been calculated once, the current temperature may be calculated by applying the temperature change to the previously calculated temperature without using the reference temperature.

[0034] The detector 25 also acquires a reference humidity (reference relative humidity) from a humidity sensor 27 (FIG. 2) provided in the vehicle interior to detect the humidity around the windshield 11 and the humidity inside the vehicle interior. For example, the humidity sensor 27 is configured as an electrical sensor. The detector 25 measures the amount of strain at each measurement point (a plurality of measurement points set on each of the first and second protrusions 22a and 23a) set on the first optical fiber 21a using the method described above with reference to FIG. 3, and calculates the humidity change at each measurement point based on the amount of strain. In this case, the detector 25 calculates the humidity change based on the amount of strain of the first optical fiber 21a excluding the amount of strain caused by temperature change (the amount of strain measured by the second optical fiber 21b as described above may be used), i.e., the amount of strain caused only by humidity change. The detector 25 then calculates (detects) the humidity at each measurement point by applying the humidity change to the reference humidity. When the detector 25 performs the humidity detection process for the first time, it calculates the humidity using the reference humidity in this manner, and once the humidity has been calculated, it may calculate the current humidity by applying the humidity change to the humidity calculated previously without using the reference humidity.

[0035] In the vehicle state quantity detection device 20, the air conditioning controller 50 controls the air conditioning of the defroster system 30 so as to defog the windshield 11 while reducing the energy consumption of the defroster system 30, based on the temperature and humidity at each measurement point detected by the detector 25 as described above, i.e., the temperature distribution and humidity distribution near the surface of the windshield 11. For example, the detector 25 determines whether fogging has occurred on the windshield 11 and the location of the fogging based on the detected temperature distribution and humidity distribution, and the air conditioning controller 50 controls the defroster system 30 based on this determination result. Specifically, the air conditioning controller 50 controls the temperature of the air blown out from the air outlet 31, the amount of air (air volume) blown out from the air outlet 31, etc. In addition, the air conditioning controller 50 also controls the switching of the air outlet 31 that blows out between the driver's seat side and the passenger's seat side, that is, controls the air to be blown out from one or both of the air outlet 31 on the driver's seat side and the air outlet 31 on the passenger's seat side (see Figure 1).

[0036] [Optical fiber configuration]

[0037] Next, a specific configuration of the optical fiber 21 according to this embodiment will be described with reference to Fig. 4 to Fig. 6. First, with reference to Fig. 4 and Fig. 5, an air layer (condensation air layer) that contributes to condensation and occurs near the surface of the front windshield 11 on the passenger compartment side will be described.

[0038] FIG. 4 schematically shows changes in state quantities, particularly temperature changes, from the outside of the vehicle to the inside of the vehicle across the windshield 11. The horizontal direction in FIG. 4 indicates the out-of-plane direction Z, and the vertical direction in FIG. 4 indicates temperature changes. Also, symbol AL1 in FIG. 4 indicates a condensation air layer. As shown in FIG. 4, it can be seen that the air temperature changes nonlinearly near the surface of the windshield 11 outside the vehicle, changes linearly inside the windshield 11, changes nonlinearly near the surface of the windshield 11 inside the vehicle (arrow A1), and becomes constant in a region inside the vehicle away from the surface of the windshield 11. Here, the region near the surface of the windshield 11 where the air temperature changes nonlinearly inside the vehicle becomes an air boundary layer, and this layer becomes the condensation air layer AL1.

[0039] In this embodiment, the vehicle state quantity detection device 20 detects the state quantities, particularly the temperature and humidity distributions, in the condensed air layer AL1 described above, from the viewpoint of realizing air conditioning control that can defog the windshield 11 while reducing the energy consumption of the defroster system 30. The condensed air layer AL1 has a thickness of approximately 1 to 5 mm, and the temperature and humidity change in the thickness direction of the condensed air layer AL1 on the order of several millimeters. It is difficult to accurately detect the temperature and humidity distributions in the condensed air layer AL1 using a general thermocouple or an electric humidity sensor. Therefore, in this embodiment, the temperature and humidity distributions in the condensed air layer AL1 are detected using an optical fiber 21 (FIGS. 1 and 2). This is because, unlike a thermocouple or an electric humidity sensor, the optical fiber 21 can precisely detect changes in the state quantities at various locations along its length.

[0040] Next, Fig. 5 is a diagram showing an example of the change in thickness of the condensation air layer AL1 in an in-plane direction. The horizontal direction in Fig. 5 indicates the out-of-plane direction Z, specifically the thickness of the condensation air layer AL1 extending in the out-of-plane direction Z, and the vertical direction in Fig. 5 indicates the vertical direction Y (approximately the vehicle height direction) defined as an in-plane direction. In other words, Fig. 5 shows the change in thickness of the condensation air layer AL1 in the vertical direction Y of the front windshield 11. Note that Fig. 5 shows the thickness of the condensation air layer AL1 at an arbitrary position in the horizontal direction X (vehicle width direction) of the front windshield 11.

[0041] As shown in FIG. 5, it can be seen that the thickness of the condensation air layer AL1 varies in the vertical direction Y of the windshield 11, that is, the thickness of the condensation air layer AL1 is not uniform in the in-plane direction, the vertical direction Y. More specifically, it can be seen that the thickness of the condensation air layer AL1 increases upward on the windshield 11, or in other words, decreases downward on the windshield 11. This is due to the influence of air (wind) from the defroster system 30 blown up from the air outlet 31 below the windshield 11. That is, the condensation air layer AL1 formed at the bottom of the windshield 11 is thin because it is heavily influenced by the wind from the defroster system 30, while the condensation air layer AL1 formed at the top of the windshield 11 is thick because it is less influenced by the wind from the defroster system 30. Furthermore, the thickness of the condensation air layer AL1 formed at the bottom of the windshield 11 is easily variable because it is heavily influenced by the wind from the defroster system 30.

[0042] In this way, the temperature distribution and humidity distribution near the surface of the windshield 11 change depending on the thickness of the condensed air layer AL1, which changes in the in-plane direction of the windshield 11. Therefore, in this embodiment, the temperature distribution and humidity distribution near the surface of the windshield 11 are detected by the optical fiber 21, taking into account the thickness of the condensed air layer AL1, which changes in the in-plane direction of the windshield 11. In particular, in this embodiment, first and second protrusions 22, 23 extending in the out-of-plane direction Z are formed on the optical fiber 21 ( FIG. 1 ), so that the temperature distribution and humidity distribution near the surface of the windshield 11 can be detected with high accuracy regardless of the thickness of the condensed air layer AL1, which changes in the in-plane direction. The temperature distribution and humidity distribution are detected using a plurality of measurement points set in these first and second protrusions 22, 23, respectively.

[0043] Next, the specific configuration of these first and second protrusions 22, 23 will be described with reference to Fig. 6. Fig. 6 shows a cross-sectional view taken along line VI-VI in Fig. 1. For ease of explanation, Fig. 6 shows a side view of the first and second protrusions 22, 23 of the optical fiber 21, and a cross-sectional view of the front windshield 11 and the rearview mirror 15.

[0044] As shown in FIG. 6, the optical fiber 21 according to the present embodiment includes a first protruding portion 22 provided at the upper part (near the upper end) of the front window 11 and formed in a rod shape (linear shape), and a second protruding portion 23 provided at the lower part (near the lower end) of the front window 11 and formed in a substantially circular spiral shape. The spiral shape of the second protruding portion 23 is formed with a bending radius (for example, a bending radius of 10 mm or more) that does not affect the reflection of light within the second protruding portion 23. Further, the first protruding portion 22 is provided such that the end portion on the rear side of the vehicle (that is, the distal end) is located on the front side of the vehicle with respect to the rearview mirror 15. Since the optical fiber 21 is formed of a single optical fiber, the first and second protruding portions 22 and 23 are formed so as to extend from the surface of the front window 11 and then return to the surface of the front window 11. In FIG. 6, the illustration of the portions where the first and second protruding portions 22 and 23 return to the surface of the front window 11 is omitted.

[0045] Further, in the optical fiber 21 according to the present embodiment, the length L2 in the longitudinal direction of the second protruding portion 23 is shorter than the length L1 in the longitudinal direction of the first protruding portion 22 (L2 < L1). These lengths L1 and L2 in the longitudinal direction are the lengths from the proximal ends (the end portions on the front side of the vehicle, corresponding to the portions attached to the surface of the front window 11 in the optical fiber 21) of the first and second protruding portions 22 and 23 to the distal ends (the end portions on the rear side of the vehicle) of the first and second protruding portions 22 and 23.

[0046] In particular, in this embodiment, the longitudinal lengths L1 and L2 of the first and second protrusions 22 and 23 are set to lengths corresponding to the thickness of the condensation air layer AL1. As shown in FIG. 6, the condensation air layer AL1 thickens upward on the windshield 11 due to the influence of wind from the defroster system 30 (indicated by the open arrow) (see also FIG. 5). In this embodiment, taking into account such changes in the thickness of the condensation air layer AL1 in the in-plane direction, the longitudinal length L2 of the second protrusion 23 located at the lower part is set to be short in accordance with the thickness of the condensation air layer AL1, which is thinner at the lower part of the windshield 11, and the longitudinal length L1 of the first protrusion 22 located at the upper part is set to be long in accordance with the thickness of the condensation air layer AL1, which is thicker at the upper part of the windshield 11. For example, the thicknesses of the condensation air layer AL1 at various positions in the in-plane direction may be determined in advance by experiment or simulation, and the longitudinal lengths L1 and L2 of the first and second protrusions 22 and 23 may be designed based on these thicknesses.

[0047] Furthermore, in this embodiment, as described above, the detector 25 of the vehicle state quantity detection device 20 detects temperature and humidity by measuring reflected light generated at the first and second protrusions 22, 23 of the optical fiber 21. Specifically, the detector 25 detects temperature and humidity distributions by measuring reflected light generated at a plurality of measurement points 22p, 23p set in advance in the first and second protrusions 22, 23, respectively. These measurement points 22p, 23p are set at different positions in the out-of-plane direction Z on the first and second protrusions 22, 23, respectively. This makes it possible to detect temperature and humidity at a plurality of different positions in the out-of-plane direction Z within the condensation air layer AL1 for the same position in the in-plane direction, i.e., to detect temperature and humidity distributions in the out-of-plane direction Z. In particular, in this embodiment, the number of measurement points 23p set on the second protrusion 23 is greater than the number of measurement points 22p set on the first protrusion 22. As a result, by using a large number of measurement points 23p set on the second protrusion 23, it is possible to ensure accurate detection of the temperature distribution and humidity distribution for the thin condensation air layer AL1 that occurs at the bottom of the front window 11 and whose thickness is prone to fluctuate.

[0048] Furthermore, in this embodiment, the second protrusion 23 is formed in a spiral shape, so that the second protrusion 23 can be configured to be longer than the first protrusion 22, which is formed in a straight line. In other words, the second protrusion 23 can be configured to have a long overall length without being long in the longitudinal direction. This makes it possible to accurately set a large number of measurement points 23p on the second protrusion 23. In other words, the multiple measurement points 23p need to be set at a certain distance from each other due to limitations in the resolution of detection using the optical fiber 21, but by configuring the overall length of the second protrusion 23 to be long, it is possible to set a large number of measurement points 23p on the second protrusion 23 with ample space to spare.

[0049] The multiple measurement points 23p set on the spiral-shaped second protrusion 23 may have the same or different in-plane positions (i.e., positions defined in the horizontal direction X and the vertical direction Y). When the multiple measurement points 23p have different in-plane positions, it is preferable to set the positions of the measurement points 23p within a range that does not cause differences in temperature or humidity due to differences in in-plane positions.

[0050] [Action and effect] Next, the operation and effect of the vehicle state quantity detection device 20 according to this embodiment will be described. In this embodiment, the vehicle state quantity detection device 20 includes an optical fiber 21 attached to the surface of the vehicle's front windshield 11 so as to extend along the surface facing the passenger compartment and passing through at least the upper and lower parts of the front windshield 11, and a detector 25 connected to the optical fiber 21 and configured to detect the temperature and humidity near the surface of the front windshield 11 by measuring reflected light of light incident on the optical fiber 21. The optical fiber 21 is provided at the upper part of the front windshield 11 and detects the temperature and humidity near the surface of the front windshield 11. and a second protrusion 23 provided at the bottom of the front windshield 11 and protruding from the surface of the front windshield 11 toward the passenger compartment, the second protrusion 23 having a shorter longitudinal length than the first protrusion 22. The detector 25 detects temperature and humidity by measuring reflected light generated at the first and second protrusions 22, 23, and is configured to set more measurement points 23p of reflected light at the second protrusion 23 than measurement points 22p of reflected light at the first protrusion 22.

[0051] In this embodiment, the longitudinal lengths L1, L2 of the first and second protrusions 22, 23 formed on the optical fiber 21 are set in consideration of the characteristic that the condensation air layer AL1 becomes thinner as it moves downward on the windshield 11 (in other words, thicker as it moves upward) due to the influence of wind from the defroster system 30. Specifically, the longitudinal length L2 of the second protrusion 23 located at the lower part is made shorter in accordance with the thickness of the condensation air layer AL1, which becomes thinner at the lower part of the windshield 11, and the longitudinal length L1 of the first protrusion 22 located at the upper part is made longer in accordance with the thickness of the condensation air layer AL1, which becomes thicker at the upper part of the windshield 11. As a result, according to this embodiment, the first and second protrusions 22, 23 formed on the optical fiber 21 can accurately detect the temperature and humidity distributions in the condensation air layer AL1 at different positions in the in-plane direction. In this case, it is possible to prevent the occurrence of areas in the condensation air layer AL1 where the temperature and humidity are not detected, or to prevent the temperature and humidity outside the condensation air layer AL1 from being detected.

[0052] Additionally, in this embodiment, the number of measurement points 23p set on the second protrusion 23 is greater than the number of measurement points 22p set on the first protrusion 22. As a result, according to this embodiment, the large number of measurement points 23p set on the second protrusion 23 ensures high accuracy in detecting the temperature distribution and humidity distribution of the thin condensation air layer AL1 that occurs below the front windshield 11 and whose thickness is prone to fluctuate.

[0053] In addition, in this embodiment, since the second protrusion 23 is formed in a spiral shape, the overall length of the second protrusion 23 can be made long, and it becomes possible to accurately set a large number of measurement points 23p on the second protrusion 23.

[0054] In addition, in this embodiment, the end (distal end) of the first protrusion 22 on the rear side of the vehicle is located further forward of the rearview mirror 15, so that the first protrusion 22 can be prevented from blocking the driver's field of vision.

[0055] Furthermore, in this embodiment, a plurality of first and second protrusions 22, 23 are provided along the vehicle width direction, so that the temperature distribution and humidity distribution near the surface of the windshield 11 can be detected over a wide range.

[0056] [Variations] Various modifications of the above-described embodiment will be described below. Note that the modifications described below can be implemented in combination with each other.

[0057] (Variation 1) Fig. 7 shows a side view of the first and second protrusions according to Modification 1 of this embodiment (the front windshield 11 is shown in cross section). In the above-described embodiment, the first protrusion 22 is formed in a rod shape, and only the second protrusion 23 is formed in a spiral shape. However, in Modification 1, as shown in Fig. 7, not only the second protrusion 23 but also the first protrusion 22x is formed in a spiral shape. According to Modification 1, the overall length of the first protrusion 22x can be increased, and a large number of measurement points 22p can be accurately set on the first protrusion 22x.

[0058] In addition, in Modification 1, it is preferable to make the number of turns of the spiral shape of second protrusion 23 greater than the number of turns of the spiral shape of first protrusion 22x. This allows the overall length of second protrusion 23 to be increased, and makes it possible to reliably set more measurement points 23p on second protrusion 23 than on first protrusion 22x.

[0059] The first protrusion 22x and / or the second protrusion 23 are not limited to being formed in a substantially circular spiral shape (FIG. 7), but may be formed in a substantially polygonal spiral shape (e.g., substantially triangular, substantially rectangular, substantially pentagonal, etc.) In this case, it is preferable to form the substantially polygonal spiral shape by bending the optical fiber 21 without bending it.

[0060] (Variation 2) FIG. 8 shows a side view of the first and second protrusions according to Modification 2 of this embodiment (the front windshield 11 is shown in cross section). As shown in FIG. 8, Modification 2 has support posts 28, 29 attached to the surface of the front windshield 11. These support posts 28, 29 respectively fix the first and second protrusions 22x, 23 formed in a spiral shape. In this case, the first and second protrusions 22x, 23 are wound in a spiral shape around the outer peripheral surfaces (outside surfaces) of the support posts 28, 29. According to Modification 2, movement of the first and second protrusions 22x, 23 due to wind from the defroster system 30 can be suppressed.

[0061] The supports 28 and 29 are preferably made of a material that has lower thermal conductivity and is less susceptible to thermal expansion than the optical fiber 21. In addition, when the first protrusion 22 formed in a rod shape is used as in the above embodiment (FIG. 6), the supports 28 do not need to be used.

[0062] (Variation 3) FIG. 9 shows a side view of the first and second protrusions according to Modification 3 of this embodiment (the front window 11 is shown in cross section). As shown in FIG. 9, in Modification 3, the first and second protrusions 22y, 23y are formed in a zigzag shape. Even when the first and second protrusions 22y, 23y are formed in a zigzag shape, the overall length can be made longer than when they are formed in a straight line, and a large number of measurement points 22p, 23p can be accurately set. Note that even when a zigzag shape is used, it is preferable to curve the optical fiber 21 without bending it.

[0063] (Variation 4) In the above-described embodiment, the vehicle state quantity detection device 20 detects both the temperature and humidity near the surface of the front windshield 11, but in the fourth modification, it may detect only one of the temperature and humidity, or it may detect a state quantity other than the temperature and humidity as long as it can be measured by the optical fiber 21. [Explanation of symbols]

[0064] 11 Front window 15. Rearview mirror 20 Vehicle state quantity detection device 21 Optical Fiber 21a First optical fiber 21b Second optical fiber 22 1st protrusion 22p, 23p measurement point 23 Second protrusion 25 detectors 28, 29 pillars 30 Defroster System 31 Ventilation vent 50 Air conditioning controller 100 Vehicle air conditioning control system AL1 Condensation air layer X horizontal direction Y vertical direction Z out-of-plane direction

Claims

1. A vehicle state quantity detection device for detecting a state quantity inside a vehicle, an optical fiber attached to a surface of a vehicle front windshield facing a passenger compartment so as to extend along the surface and pass through at least an upper portion and a lower portion of the front windshield; a detector connected to the optical fiber and configured to detect a state quantity near the surface of the windshield by measuring reflected light of light incident on the optical fiber; and the optical fiber includes a first protrusion provided on an upper portion of the front window and protruding from the surface of the front window toward the vehicle interior, and a second protrusion provided on a lower portion of the front window and protruding from the surface of the front window toward the vehicle interior, The second protrusion is formed to have a length in a longitudinal direction shorter than that of the first protrusion, the detector detects the state quantity by measuring the reflected light generated at the first and second protrusions, and is configured to set more measurement points of the reflected light at the second protrusion than measurement points of the reflected light at the first protrusion. A vehicle state quantity detection device characterized by:

2. The vehicle state quantity detection device according to claim 1 , wherein the second protrusion is formed in a spiral shape.

3. The vehicle state quantity detection device according to claim 1 or 2, wherein the first protrusion is formed in a spiral shape.

4. 4. The vehicle state quantity detection device according to claim 3, wherein the second protrusion has a greater number of turns of the spiral shape than the first protrusion.

5. The vehicle state quantity detection device according to claim 1 or 2, further comprising a support attached to the surface of the windshield, to which the second protrusion is fixed.

6. The vehicle state quantity detection device according to claim 1 or 2, further comprising a support pillar attached to the surface of the windshield, to which the first protrusion is fixed.

7. The vehicle state quantity detection device according to claim 1 or 2, wherein a rear end of the first protrusion is located forward of a rearview mirror of the vehicle.

8. The vehicle state quantity detection device according to claim 1 or 2, wherein a plurality of the first protrusions and / or a plurality of the second protrusions are provided along a vehicle width direction.

9. 3. The vehicle state quantity detection device according to claim 1, wherein the state quantity is a temperature and / or humidity in the vicinity of the surface of the windshield.

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