WO2009084855A2

WO2009084855A2 - Anti-fog device for automobiles

Info

Publication number: WO2009084855A2
Application number: PCT/KR2008/007650
Authority: WO
Inventors: Hi-Ryong Byun
Original assignee: Pukyong National University Industry-University Cooperation Foundation
Priority date: 2007-12-28
Filing date: 2008-12-24
Publication date: 2009-07-09
Also published as: WO2009084855A3; KR20090072426A

Abstract

An anti-fog device for an automobile for preventing a windshield glass of the automobile from steaming up using a coolant heated by an engine of the automobile as a heat source is provided. The anti-fog device includes a hot wire formed of a material having excellent thermal con¬ ductivity. Here, one end of the hot wire is connected to the engine and the other end of the hot wire is vertically connected to a side portion of the windshield glass to prevent the windshield glass from steaming up using the heat transmitted from the engine.

Description

ANTI-FOG DEVICE FOR AUTOMOBILES

Technical Field

[1] The present invention relates to an anti-fog device for an automobile, and more particularly, to an anti-fog device for an automobile with an improved structure that is connected to an engine or a coolant of the engine to prevent a windshield glass from steaming up using heat of the engine. Background Art

[2] The steam-up in automobiles has bothered drivers regardless of seasons since the automobiles were invented. A lot of studies and patent applications were made historically, but the steam-up was not basically solved due to the misunderstanding of the cause for the steam-up. It has been generally understood as the cause for the steam-up that the indoor temperature of the automobiles is higher than the temperature of a windshield glass. Accordingly, when the windshield glass steams up, devices and methods of supplying hot air to the windshield glass, such as a heater of the windshield glass such as hot wires and a sensor sensing temperature, humidity, rainfall, etc. to determine a time for supplying hot air and a windshield heater controller (see KR Patent Application Nos. 2003-74186 and 2003-9707), were suggested. However, an anti-fog effect thereof was not improved in spite of the trouble and cost for providing such devices.

[3] On the basis of the understanding that the steam-up occurs due to a high relative humidity, a method of lowering the relative humidity might be suggested. That is, a principle that the temperature is lowered to lower the humidityby actuating an air conditioner was used. However, this method has a problem that many devices and sensors or an air-conditioning system (see KR Patent Application No. 2001-86022) are required for predicting the time for actuating the air conditioner in advance. The above-mentioned methods were based on the basic thermodynamic misunderstanding on the steam-up.

[4] In addition to the above-mentioned anti-fog methods, a method of attaching an anti- fog material to the windshield glass is known. An example of the anti-fog material includes an anti-fog spray or an anti-fog film. These products are consumption goods and thus cause inconvenience of lasting purchase and replacement. The anti-fog effect thereof is restricted. Accordingly, when the steam-up is great, the products are useless.

[5] To contrive a method not employing the above-mentioned principle, engineers have studied one the anti-fog by a lot of calculations and trial and error. The humidity should be measured for the calculations. However, the humidity is an element having the greatest measurement error of atmospheric elements and thus is hardly measured accurately, thereby making accurate diagnosis and treatment difficult. [6]

Disclosure of Invention

Technical Problem

[7] The invention is made to solve the above-mentioned problems. An advantage of some aspects of the invention is to provide an anti-fog device for an automobile that can reduce energy and enhance cooling efficiency of an engine of an automobile by using heat of the engine and that can guarantee safe driving. Technical Solution

[8] According to an aspect of the invention, there is provided an anti-fog device for an automobile for preventing a windshield glass of the automobile from steaming up using a coolant heated by an engine of theautomobile as a heat source, the anti-fog device including: a hot wire formed of a material having excellent thermal conductivity. Here, one end of the hot wire is connected to the engine and the other end of the hot wire is vertically connected to a side portion of the windshield glass to prevent the windshield glass from steaming up using the heat transmitted from the engine.

[9]

[10] The surface of the hot wire may be coated with a heat insulating material.

[11] The other end of the hot wire may come in simultaneous contact with an indoor surface and an outdoor surface of the windshield glass.

Advantageous Effects

[12] The anti-fog device of an automobile according to the aspect of the invention can prevent steam in the automobile from being condensed on the surface of the windshield glass by raising the temperature of the windshield glass using waste heat of the engine. Conclusively, it is possible to prevent the windshield glass from steaming up and to guarantee a driver's visual field, thereby allowing safe driving. In addition, since an air conditioner or a heater need not be turned on to remove the steam, it is possible to save energy. Since the function of a radiator diffusing the heat of the engine is promoted, it is possible to enhance the thermal efficiency of the engine. Brief Description of Drawings

[13] FIG. 1 is a diagram schematically illustrating an anti-fog device for an automobile according to an exemplary embodiment of the invention.

[14] FIG. 2 is a sectional view taken along line II- II of FIG. 1.

[15] FIG. 3 is a sectional view taken along line III-III of FIG. 1.

[16] FIG. 4 is a sectional view of an anti-fog device according to another exemplary embodiment of the invention, which corresponds to FIG. 3. [17]

Best Mode for Carrying out the Invention

[18] Hereinafter, exemplary embodiments of the invention will be described in detail with reference to the accompanying drawings.

[19] FIG. 1 is a diagram schematically illustrating an anti-fog device for an automobile according to an exemplary embodiment of the invention. FIG. 2 is a sectional view taken along line II- II of FIG. 1. FIG. 3 is a sectional view taken along line III-III of FIG. 1.

[20] As shown in FIGS. 1 to 3, an anti-fog device for an automobile according to an exemplary embodiment of the invention includes a hot wire 30 and a coating member 40.

[21] One end of the hot wire 30 is connected to an engine 20. More specifically, one end of the hot wire 30 is preferably connected to a point where the temperature of a coolant is highest to use the heat of the coolant of the engine 20 as a heat source. The hot wire 30 may come in direct contact with the coolant or may come in indirect contact with the coolant to receive only the heat of the coolant instead of coming in direct contact with the coolant. The other end of the hot wire 30 is connected to a side portion of a windshield glass 15. The hot wire 30 is preferably formed of a copper wire having relatively excellent thermal conductivity. The other end of the hot wire 30 is disposed vertically in both side portions of the windshield glass along a front pillar of the automobile. The other end of the hot wire 30 comes in simultaneous contact with an indoor surface 16 and an outdoor surface 17 of the windshield glass 15. That is, as shown in FIG. 2, the other end of the hot wire 30 is branched to simultaneously transmit the heat to the indoor surface 16 and the outdoor surface 17 of the windshield glass 15. The coating member 40 coating the surface of the hot wire to prevent the hot wire 30 from being damaged is disposed between one end and the other end of the hot wire 30. The coating member 40 is preferably formed of a heat insulating material having very low thermal conductivity. The coating member 40 preferably extends to the other end of the hot wire 30. It is preferable that means for intercepting the transmission of heat of the hot wire 30 so as not to excessively raise the temperature of the other end of the hot wire 30, for example, a heat transmitting path (not shown) through which the coolant flows to transmit the heat to a cool part of the coolant as needed and a valve (not shown) opening and closing the heat transmitting path, is further provided between one end and the other end of the hot wire 30.

[22] On the other hand, in another embodiment of the invention, as shown in FIG. 4, a hot wire 30a may include paths 32 and 34 through which the heated coolant can circulate, thereby allowing the coolant to circulate close to the windshield glass 15. [23] Operations of the anti-fog device 10 for an automobile according to this embodiment having the above-mentioned configuration will be described in detail now.

[24] First, a principle of steam-up will be described before describing the operations. A thermodynamic principle of the steam-up can be expressed by Expression 1.

[25] Expression 1

[26] E=(a+b*U)(e -e ) w a

[27] Expression 1 was known by Penman of England in 1948 and was verified by Cho,

H. K. of Korea in 1969 and by Han and Lee of Korea in 2005 (References: (1) Penman, H. L., 1948: Proc. Roy. Soc. London, A., 193, 120-146. (2) J.S. Han and B.S. Lee, 2005: "Measurement and analysis of free water evaporation at Haenam paddy field," Korean Journal of Agricultural and Forest Meteorology. 7-1. 92-98. (3) H.K. Cho, 1969: Estimation of evaporation by using a simple empirical mass-transfer method. J. of Kor. Met. Soc. 5-1, 3-9. (Written in Korean with English abstract)). In Expression 1, E represents the evaporation loss and a and b are constants varying depending on the surface from or on which water is evaporated or condensed. U represents the wind velocity around the surface. In Expression 1, e a represents an indoor vapor pressure and e w represents a saturated vapor pressure of air having the same temperature as the indoor surface of the windshield glass of the automobile. When a pressure is constant, the saturated vapor pressure is a function of only temperature. Accordingly, Expression 1 means that the steam-up depends on a difference between the dew point in the automobile and the temperature of air adjacent to the windshield glass 15. When the temperature of the air adjacent to the windshield glass 15 is considered as being equal to the temperature of the windshield glass 15 and the dew point of the indoor air is higher than the temperature of the windshield glass 15, the condensation, that is, the steam-up, occurs. Accordingly, when the temperature of the windshield glass 15 is higher than the dew point of the indoor air, the steam-up does not occur. That is, a, b, and U in Expression 1 always have positive values. Therefore, when (e -e )>0, thee- w a vaporation occurs from the indoor surface 16 of the windshield glass 15. When (e -e ) w a

<0, the condensation occurs on the indoor surface 16 of the windshield glass 15. [28] The operations will be described on the basis of the above-mentioned principle. In general, the temperature of the coolant of the engine 20 is maintained in the range of 7OC to 80C in a state where the engine 20 normally operates. The hot wire 30 receives heat from the coolant of the engine 20. That is, one end of the hot wire 30 has the temperature close to 7OC to 80C. The heat is transmitted to both side portions of the windshield glass 15 connected to the other end of the hot wire 30 via the hot wire 30. Since the other end of the hot wire 30 comes in simultaneous contact with the indoor surface 16 and the outdoor surface 17 of the windshield glass 15, the indoor surface 16 and the outdoor surface 17 of the windshield glass 15 exhibit a similar temperature dis- tribution. The windshield glass often steams up in winter or rainy days. However, since the temperature of the coolant of the engine 20 is higher than the indoor temperature or the outdoor temperature of the automobile, (e -e ) in Expression 1 has a positive value w a and thus E has a positive (+) value. Accordingly, since the surface of the windshield glass 15 is always higher than the indoor temperature and the outdoor temperature of the windshield glass 15, only the evaporation occurs and the condensation does not occur. As a result, the windshield glass 15 does not steam up. In this course, since the coolant is cooled by a radiator and the heat is transmitted to the windshield glass 15 through the hot wire 30 and then taken away to the air by wind or the like, the cooling effect of the coolant is improved. Therefore, the cooling ability of the engine 20 is improved and thus the performance of the engine 20 is incidentally improved. Since the windshield glass 15 does not steam up, a heater or an air conditioner need not be actuated. Thereby saving the energy. In addition, since the surface of the hot wire 30 is coated with the coating member 40 formed of a heat insulating material, it is possible to minimize the heat loss in the course of transmitting the heat through the hot wire 30. The coating member 40 serves to prevent the hot wire 30 from electrical contact and physical interference with various elements of an engine room.

[29] On the other hand, as shown in FIG. 4, when paths 32 and 34 through which the coolant heated by the engine 20 circulates are disposed in the hot wire 30a, the cooling effect of the engine 20 is further improved to enhance the performance of the engine 20 and to further prevent the windshield glass 15 from steaming up.

[30] Although it is described above in the embodiments of the invention that the surface of the hot wire is coated with a heat insulating material, the goal of the invention can be accomplished even when the surface of the hot wire is not coated with the heat insulating material.

[31] Although it is described above in the embodiments that the other end of the hot wire comes in simultaneous contact with the indoor surface and the outdoor surface of the windshield glass, the goal of the invention can be accomplished even when the other end of the hot wire comes in contact with only the indoor surface of the windshield glass.

[32] While the invention has been described with reference to the exemplary embodiments, the invention is not limited to the embodiments, but it will be understood by those skilled in the art that the invention can be modified in various forms without departing from the technical spirit of the invention.

Claims

[1] An anti-fog device for an automobile for preventing a windshield glass of the automobile from steaming up using a coolant heated by an engine of the automobile as a heat source, the anti-fog device comprising: a hot wire formed of a material having excellent thermal conductivity, wherein one end of the hot wire is connected to the engine and the other end of the hot wire is vertically connected to a side portion of the windshield glass to prevent the windshield glass from steaming up using the heat transmitted from the engine.

[2] The anti-fog device according to claim 1, wherein the surface of the hot wire is coated with a heat insulating material.

[3] The anti-fogdevice according to claim 1, wherein the other end of the hot wire comes in simultaneous contact with an indoor surface and an outdoor surface of the windshield glass.

[4] The anti-fog device according to claim 1, wherein the hot wire has a path through which the coolant heated by the engine can circulate therein.