JPS5858454A - Cloud detector for vehicle - Google Patents

Abstract

PURPOSE:To cloud a dew condensation sensor part fast to foresee the occurrence of the cloud of a window glass, by sticking the dew condensation sensor to the surface in the side of car room through a thermoelectric element and adjusting the temperature of the sensor part. CONSTITUTION:A dew condensation sensor 2 is stuck to a car room-side surface 3a of a front wind shield glass 3 of a vehicle through a thermoelectric element 6 with paste 5 or the like and is shielded from direct rays of the sum by a light shielding tape 10. When the temperature of the part to which the sensor 2 is attached is made lower than that of other parts on the surface 3a by the element 6, the cloud occurs in this part faster than other parts and is detected by the sensor 2. Consequently, the occurrence of the cloud on the front wind shield glass or the like is foreseen on the basis of the detection signal of the sensor 2.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fogging detection device for a vehicle that detects fogging of a windshield such as a rear windshield glass using a dew condensation sensor attached to the windshield.

As shown in Fig. 1, conventional vehicle dew detection devices are constructed by attaching a dew condensation sensor directly to the single-chamber side surface of the rear windshield glass l, for example, when the rear windshield glass is clogged. It is used as an automatic switching means for a hot wire type auto defogger that automatically removes this distortion.

The fogging of the windshield is caused by the fact that when the vehicle is being used in cold weather and the interior of the vehicle is heated, the heated interior of the vehicle is rapidly cooled down when it comes into contact with the single-chamber side surface of the windshield that has been cooled by low-temperature outside air. This occurs as a result of condensation on the single room side surface of the window glass. At this time, the relative humidity on the surface of the single room side of the window glass becomes IOO 96, and has the relative humidity-resistance value change characteristic as shown in Figure 1, for example.
The dew condensation sensor whose resistance value increases rapidly at the relative humidity above starts a switching action at a relative humidity of 100%, and can detect fogging on the windshield.

However, in such conventional fogging detection devices, the main dew condensation sensor is attached directly to the surface of the window glass on the passenger compartment side, so a signal corresponding to the fogging is emitted only after the surface of the window glass becomes foggy. Until the auto defogger was able to fully utilize its function, the driver was forced to drive with the windshield fogged up, which was dangerous due to the lack of visibility.

This danger can be avoided by installing a condensation sensor on the front windshield glass pane and using it as a switching means to automatically defog the windshield (e.g. a humidity control device or a dehumidifying device for an auto air conditioner). In this case, the visibility of the front windshield glass plays an important role in driving safety, so this becomes even more noticeable.

In the present invention, a dew condensation sensor is attached to the surface of the windshield on the passenger compartment side through a thermoelectric element, and a current is supplied to the thermoelectric element to lower the temperature of the dew condensation sensor than the temperature of the surface of the windshield on the passenger compartment side. The idea is that fogging of the fog sensor will occur earlier than the fogging of the windshield due to this temperature difference, and fogging of the windshield can be predicted from the sensor, thereby solving the problem of the conventional device described above. Therefore, it is an object of the present invention to provide a fogging detection device for a vehicle that embodies this idea.

Hereinafter, the present invention will be described in detail based on the illustrated implementation numbers, and its effects will be mentioned.

Figure 3 shows the health detection device 1 of the present invention installed on the passenger compartment side surface of the front windshield glass J, where the delay in health detection poses a problem in terms of driving as described above.

The apparatus of the present invention is shown in Fig. V, which is a cross-sectional view of Mu A in Fig. 3, and Fig. J, which is a perspective view of the same cross-sectional portion. and a dew condensation sensor φ similar to that used in the conventional device.The thermoelectric element 6 is stuck in the paste z and is pasted on the single-chamber side surface of the front windshield glass 3, and the pasted point is placed on the windshield glass. The fog sensor is attached to the windshield surface using a conventional adhesive, for example, as shown in Fig. 3, at the upper left corner farthest from the steering wheel 7. Glue the surface farthest from 3a due to heat conduction relationship ε.

That is, the dew condensation sensor is pasted on the single room side surface 3 of the window glass via the thermoelectric element B.

The thermoelectric element 6 is a well-known commercially available product, and by connecting a constant current source as shown in FIG. 6 through the lead hr (see FIG. q), a constant current 1 can be supplied from the constant current source. shall be. and - the thermoelectric element 6 has a surface 4 close to the windshield 3;
a to the window glass surface 3 with a good thermal conductive paste j.
When the same temperature t as & is applied, but when the above constant 1[, current 1 is supplied, the surface 6b to which the dew condensation sensor λ is bonded will be at a temperature corresponding to the current in question with the characteristics shown in Fig. 7. It shall be possible to maintain a height lower than 4m. Also, the constant current 1 depends on how much lower temperature the surface Ab of the thermoelectric element 6 should be than the surface 6&, that is, the amount of fog that is bonded to the surface Ab by a thermal conductor and brought to the same temperature. The surface 4a, that is, the windshield surface 3&
You can decide freely depending on how low you want it to be.

The operation of the apparatus of the present invention having the above-mentioned structure will be explained below.

FIG. 1 shows the relationship between dry bulb temperature and water vapor partial pressure in the air using relative humidity [R, Ho as parameters. The water vapor partial pressure in the air inside the metal car is /fllHg, and the windshield surface Ja
Dry bulb temperature T above. However, assuming that the temperature is 23°C, the relative humidity R of the air in contact with the window glass surface 3a at this time is
H, is II%, and although the surface of the window glass is not yet cloudy, it is in a good condition. Then, the partial pressure of water vapor in the air inside the vehicle rises from the exhalation of the occupant, and λ3
When the relative humidity of the air in contact with the windshield surface Ja finally reaches 100%, the windshield surface begins to fog up.

On the other hand, the constant current 1 is supplied to the thermoelectric elements, 44, and the temperature of the surface 4b, which is brought to the same temperature as the windshield surface 3& as described above, that is, the temperature T of the fog sensor, is controlled by the constant current 1.
If the temperature is set to 3 degrees lower than the appropriate temperature setting, the temperature T of the dew condensation sensor λ will be -j'c-3°C=-0'C:. Therefore, even under the same water vapor partial pressure/lsslHg, the relative humidity R, H, of the air in contact with the fog sensor is 10
0%, and before the windshield surface 3μ begins to fog, the windshield sensor λ is disconnected and fogs up, and the sensor is able to issue a calming signal, making the windshield surface 3μ easy to fog. It can be predicted that

Thus, as described above, in the vehicle stagnation detection device of the present invention, the fog sensor 2, which is the detection element, is attached to the windshield surface 3 through the thermoelectric element B, and the windshield surface is heated to a certain temperature above the windshield surface. Since the structure is configured to keep the temperature low, it is possible to predict the windshield locking very quickly (this temperature difference), and to activate a device to deal with this before the windshield actually fogs up, thereby preventing the windshield from constantly fogging. To enable safe driving under such conditions.

In the above-mentioned example, the thermoelectric element At constantly supplies a constant current of 1, but the constant current is supplied only when the temperature inside the thermoelectric compartment is lower than the outside temperature (such as when cooling the interior of a vehicle in summer, etc.). , if there is no risk of the windshield settling down, it can be stopped automatically or manually, or it can be pumped intermittently at regular intervals even in a state where constant current 1 should be supplied. In this case, power consumption can be reduced.

By the way, during the operation of the device of the present invention, the temperature distribution inside and outside of the window glass J, the device of the present invention on which it is placed, and the temperature distribution between them becomes as illustrated by the solid line in the diagram, and the windshield surface Temperature T of Ha. Due to the difference in temperature between the hot air and the temperature of the air that comes into contact with it, the surface of the windshield becomes burnt, and the temperature difference between the front and back surfaces of the thermoelectric wire. -Tf Komari Present invention device 4I41 The health of the window glass surface can be predicted as explained above. However, superposition f! When direct sunlight shines through the window glass 3, the temperature distribution will be as shown in Figure 1.
The temperature changes as shown by the dotted chain line. At this time, the temperature T of the window glass surface l1kIJ&. ' and the temperature of the air in contact with it [T' are respectively heated by the solar radiation chamber, resulting in a temperature T.

Although the amount of temperature rise is almost the same for both T and T, the temperature difference T and T is almost equal to T and T. However, when the thermoelectric element 6 is heated by solar radiation, even if the same constant voltage IXi is supplied, the surface temperature difference T.'- is shown in Table 1! As shown in Figure 2, T' is smaller than T in the absence of solar radiation.

Therefore, in this case, although the device according to the invention can perform exactly one of the above operations, it is sometimes impossible to predict the fogging of the windshield.

If this situation becomes a major problem, it is necessary to shield the thermoelectric element t, including the dew condensation sensor, from direct sunlight. For this purpose, as shown in the 10th edition, a light-shielding tape or light-shielding tape or light-shielding tape was applied to the single outer surface sb of the windshield 3, opposite to where the device l of the present invention was provided. It is better to paste or apply the paint 10 and rub it gently to prevent direct sunlight from hitting the device of the present invention. In this case, the light-shielding tape 11 is the pace I of the above embodiment.
Similar to -j, the thermoelectric element t is also used to attach the heat conduction plate to the window glass surface 3sLtI, and the paste of the above embodiment! omitted.

[Brief explanation of drawings]

Fig. 1 is a perspective view of the rear of a vehicle showing a conventional vehicle overload detection device, Fig. 2 is a diagram showing the operating characteristics of a dew condensation sensor, which is the detection element of the device, and Fig. 3 is an example of application of the device of the present invention. A front view of the front windshield glass shown from inside the vehicle,
5 is a sectional view taken along line A in FIG. 3, FIG. 5 is a perspective view of the same cross-sectional area, FIG. 5 is a block diagram of the device of the present invention, and FIG. Figure 1 is a diagram showing the change in dry bulb temperature and water vapor partial pressure using relative temperature as a parameter. Figure 10 and 1st
/ Figures are sectional views similar to Figure V showing other examples of the present invention. J. Front windshield glass, Hiroshi...Fog detection device of the present invention, J. Paste, 6. Thermoelectric element, T.
・Lead wire, constant current source, IO-light-shielding tape or light-shielding paint, ll...light-shielding tape. Figure 1 Figure 2 Figure 4 Figure 5 Figure 6

Claims (1)

[Scope of Claims] L. A fogging detection device for a vehicle that detects fogging of the windshield by a dew condensation sensor attached to the single-room side surface of the windshield. A fogging device for a vehicle, characterized in that the temperature of the dust sensor is lowered than the temperature of the single-chamber side surface of the windshield by applying current to the thermoelectronic pot. Detection device. 2. The fogging detection device for a vehicle according to claim 1, wherein the dew condensation sensor and the thermoelectric element are shielded from direct sunlight.