JP2011022015A - Environmental test method and environmental testing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an environmental test method capable of reproducing an approximately same phenomenon as frost formation generated in a natural world, and to provide an environmental testing device capable of forming frost on a test object. <P>SOLUTION: The test object 20 is arranged in a test chamber 2 of this environmental testing device 1, and a surface temperature of the test object 20 in the test chamber 2 is lowered to about 0°C or lower, and then an absolute humidity at least in the vicinity of the test object 20 is raised, and steam in the air is phase-changed on the surface of the test object 20 and/or its vicinity, to thereby form frost on the surface of the test object 20. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an environmental test method capable of reproducing substantially the same phenomenon as frost generated in nature, and an environmental test apparatus capable of frosting a test object.

  Due to a decrease in temperature due to the radiation cooling phenomenon, frost may form on vehicles or the like placed outdoors. When the vehicle is frosted, the engine is hardly warmed, and the vehicle is affected in some way. For this reason, in the past, vehicle tests were conducted in cold regions in order to investigate the effect of frost on the vehicle, but the test environment varies greatly depending on weather conditions, location, time zone, etc. It is not easy to realize.

  Therefore, Patent Document 1 discloses an invention for obtaining a similar test environment. In the snow accumulating device disclosed in Patent Document 1, it is supposed that the effect of snow accretion on the vehicle can be examined by causing the vehicle to snow.

JP 2004-140934 A

  The snow accumulating device disclosed in Patent Document 1 liquefies a part of natural snow or artificial snow with a heating source, and sprays the object that has changed into wet snow onto an object to make it snow. For this reason, the snow accretion caused by the wet snow generated by the snow accumulator is different from the frost accumulating due to the phase change of water vapor (gas) to frost (solid). Therefore, it is difficult to reproduce the same frost formation that occurs in the natural world with the conventional snow accretion device.

  Accordingly, an object of the present invention is to provide an environmental test method capable of reproducing substantially the same phenomenon as frost generated in nature, and an environmental test apparatus capable of frosting a test object.

  The invention according to claim 1 for solving the above-described problem is to place a test object in a test chamber of an environmental test apparatus, to reduce the surface temperature of the test object in the test chamber to near zero degrees Celsius, The environmental test is characterized in that at least the absolute humidity in the vicinity of the DUT is increased, and the surface of the DUT and / or in the vicinity thereof, water vapor in the air is phase-changed to form a frost on the DUT surface. Is the method.

The environmental test method of the present invention can form frost on the surface of a test object arranged in a test chamber of an environmental test apparatus.
In more detail, the surface temperature of the DUT in the test room is lowered to below zero degrees Celsius, and under that condition, at least the absolute humidity in the vicinity of the DUT is increased, and the air in the vicinity of the DUT The amount of water vapor contained in the water is increased. The increased water vapor is brought into contact with the surface of the DUT cooled to below zero degrees Celsius and / or the air in the vicinity thereof, so that heat is taken away and phase change occurs. Crystal). That is, the water vapor is phase-changed from gas to solid and condensed, which is frost. According to the present invention, frost can be generated on the surface of the object to be tested. Of the water vapor that has been cooled to near zero degrees Celsius or less, the water that has not undergone a phase change to frost is either supercooled water vapor or supercooled water droplets and is in an unstable state.

  According to the second aspect of the present invention, at least the test is performed by supplying air having a dew point temperature equal to or higher than the surface temperature of the test object so as to be in a windless state or a wind speed of 4 m / s or less near the test object. The environmental test method according to claim 1, wherein the absolute humidity in the vicinity of the object is increased.

The environmental test method of the present invention is capable of stably frosting the surface of a test object or reducing the time required for frosting.
Here, the air whose dew point temperature is equal to or higher than the surface temperature of the DUT is `` supplied so that there is no wind in the vicinity of the DUT '', for example, without using a blower or the like. It refers to a state in which the absolute humidity in the vicinity of the object to be tested is gradually increased by utilizing a diffusion phenomenon or a convection phenomenon. In the case of “supplying a windless state in the vicinity of the DUT”, in many cases, an air flow or air mixing is not artificially generated in the test chamber. As a result, the surface of the test object can be stably frosted.
On the other hand, “supplying a wind speed of 4 m / s or less near the object to be tested” artificially causes air flow or air mixing in the test chamber. This makes it possible to shorten the time required for frost formation on the surface of the test object.
The “air whose dew point temperature is equal to or higher than the surface temperature of the test object” refers to “air whose water vapor amount is saturated or supersaturated when cooled to the surface temperature of the test object”. . In order to easily generate frost on the surface of the DUT, an excessive amount of water vapor is required, and when cooling to the surface temperature of the test object, the air whose water vapor amount is saturated or supersaturated is required. Become.

  The invention according to claim 3 is characterized in that the surface temperature of the DUT is lowered to a temperature lower than or equal to about zero degrees Celsius and lower than the average temperature of the placed test room. It is an environmental test method described.

The environmental test method of the present invention lowers the surface temperature of the object to be tested to a temperature below about zero degrees Celsius and lower than the average temperature of the placed test room. In carrying out the present invention, it is desirable that the test chamber of the environmental test apparatus can arbitrarily control the temperature and humidity, but it may not have the function of controlling the temperature and humidity. .
That is, many of the test chambers of the environmental test apparatus can arbitrarily control the temperature and humidity with a heater, a refrigerator, a humidifier, etc., but in the present invention, these temperatures and humidity are controlled. Function is not essential.
For example, the temperature of the test chamber may depend on the course depending on the external environment, the surface temperature of the device under test, cold air for cooling the device under test, or the like.
In short, the requirement of the present invention is satisfied if the surface temperature of the object to be tested is lower than about zero degrees Celsius and lower than the average temperature in the test room.

  The invention described in claim 4 blows cold air over a certain period of time to lower the surface temperature of the DUT to near zero degrees Celsius, and then temporarily or permanently stops blowing the cold air. 4. The environmental test method according to claim 1, wherein after that, the absolute humidity is increased so that at least the dew point temperature of the air in the vicinity of the test object is equal to or higher than the surface temperature of the test object. It is.

  The environment test method of the present invention creates an environment in the test chamber that is substantially the same as the radiant cooling that occurs in cold regions. In other words, the radiative cooling phenomenon that occurs in nature is the reverse phenomenon of the temperature that the ground surface is cooled rather than the sky, and according to the present invention, the phenomenon that is almost the same as radiative cooling is reproduced in the test chamber, and frost is tested. Can be generated on the surface.

  The invention according to claim 5 blows cold air over a certain period of time to lower the surface temperature of the test object to near zero degrees Celsius or less, and then reduces the amount of cold given to the test object per unit time. And then increasing the absolute humidity so that at least the dew point of the air in the vicinity of the object to be tested is equal to or higher than the surface temperature of the object to be tested. Is the method.

  The environmental test method of the present invention creates an environment in the test chamber that is substantially the same as the radiant cooling that occurs in a cold region, as in the fourth aspect of the invention.

  According to the sixth aspect of the present invention, air having a dew point temperature equal to or higher than the surface temperature of the DUT is supplied to the inside of the test chamber from above the DUT so that there is no wind or a breeze in the vicinity of the DUT. The environmental testing method according to claim 1, wherein the environmental testing method is performed.

  The environment test method of the present invention creates an environment in the test chamber that is substantially the same as the radiant cooling that occurs in cold regions. In the present invention, air whose dew point temperature is equal to or higher than the surface temperature of the test object is supplied in a state close to natural convection from above in the test chamber. That is, almost the same phenomenon as radiative cooling that occurs in cold regions can be reproduced in the test chamber.

  The invention according to claim 7 is to increase the absolute humidity in the vicinity of the DUT by supplying air containing humidity to the vicinity of the DUT. The dry-bulb temperature and dew point temperature of the air supplied to the vicinity, the wind speed in the vicinity of the test object, and the strength of the cold wind that gives cold heat to the test object can be controlled. The environmental test method according to any one of the above.

The environmental test method of the present invention controls the properties (temperature, dew point temperature, etc.) of the air supplied to the DUT.
“The dry-bulb temperature of the air supplied to the vicinity of the test object” is a parameter that affects the time taken for frost formation on the surface of the test object.
The “dew point temperature of the air supplied near the DUT” is a parameter that affects the amount of water vapor contained in the air.
The “surface temperature of the DUT” is a parameter that affects the shape of frost crystals.
The “wind velocity in the vicinity of the DUT” is a parameter that affects the time required for frost formation on the surface of the DUT.
The “intensity of the cold air that gives cold heat to the test object” is a parameter that affects whether or not frost is formed on the surface of the test object. Here, “strength” is the energy of cold wind, and represents wind temperature, wind speed, and air volume.

  The invention according to claim 8 includes the surface temperature of the DUT, the dry bulb temperature of air in the vicinity of the DUT, the dew point temperature of air in the vicinity of the DUT, and the wind speed in the vicinity of the DUT. The environmental test method according to any one of claims 4 to 6, wherein the strength of the cold air that gives cold heat to the device under test can be controlled.

The environmental test method of the present invention is a control method from the viewpoint of the environment in the vicinity of the device under test, and is intended for strict temperature control and the like. Further, similarly to the seventh aspect of the invention, the air property is controlled.
The “dry bulb temperature of air in the vicinity of the test object” is a parameter that affects the time required for frost formation on the surface of the test object.
The “dew point temperature of air in the vicinity of the DUT” is a parameter that affects the amount of water vapor contained in the air in the vicinity of the DUT.

  According to the ninth aspect of the present invention, there is provided a test chamber for housing the test object, a cooling means for reducing at least the surface temperature of the test object, and at least a dew point temperature of air in the vicinity of the test object is the surface of the test object Humidifying means for increasing the absolute humidity so that the temperature is equal to or higher than the temperature. The cooling means lowers the surface temperature of the test object to near zero degrees Celsius or less, so that the surface of the test object and / or the vicinity thereof is in the air. An environmental test apparatus characterized by having the ability to change the phase of water vapor and cause the surface of a test object to be frosted.

  An environmental test apparatus according to the present invention is an apparatus for realizing the environmental test method according to claim 1, and frosts the surface of a test object placed in a test chamber as in the case of claim 1. .

  The invention described in claim 10 is the environmental test apparatus according to claim 9, characterized in that the cooling means blows cold air to the object under test to lower the surface temperature of the object under test. .

  An environmental test apparatus according to the present invention is an apparatus for realizing the environmental test method according to claim 4, and creates an environment in the test chamber that is substantially the same as radiant cooling that occurs in a cold region as in claim 4. is there.

  According to an eleventh aspect of the present invention, the cooling means and the humidifying means each have a separate blowing means, the humidifying means generates humidified air, and the humidifying air is blown to the vicinity of the test object by the blowing means. The environmental test apparatus according to claim 9 or 10, wherein

  An environmental test apparatus according to the present invention is an apparatus for realizing the environmental test method according to claim 2 or 3, and in the same manner as in claim 2 or 3, the environment substantially the same as that of radiation cooling that occurs in a cold region It is what you create. Moreover, since the cooling means and the humidifying means each have an individual air blowing means, controllability is improved by controlling the air blowing means individually.

  The invention according to claim 12 can increase or decrease the amount of cold heat given to the test object per unit time by changing the strength of the cool air or intermittently blowing the cool air to the test object. The environmental test apparatus according to claim 10 or 11, wherein

  An environmental test apparatus according to the present invention is an apparatus for realizing the environmental test method according to claim 4 or 5, and, similar to claim 4 or 5, an environment substantially the same as that of radiant cooling that occurs in a cold region It is what you create.

  The invention according to claim 13 has a high-humidity air supply port above the test chamber, and air having an absolute humidity at which the dew point temperature is equal to or higher than the surface temperature of the DUT is supplied from the high-humidity air supply port to the test chamber. The environmental test apparatus according to claim 9, wherein the environmental test apparatus is supplied to increase a humidity around the object to be tested.

  An environmental test apparatus according to the present invention is an apparatus for realizing the environmental test method according to claim 6, and creates an environment substantially the same as radiant cooling that occurs in a cold region in the test chamber as in the case of claim 6. is there.

  According to a fourteenth aspect of the present invention, the humidifying means generates humidified air and supplies the humidified air to the vicinity of the test object, and the wind speed detecting means for detecting the wind speed in the vicinity of the test object, Surface temperature detection means for detecting the surface temperature of the test object, dew point detection means for detecting the dew point temperature of the humidified air supplied to the vicinity of the test object by the humidification means, and supply to the vicinity of the test object by the humidification means Supply air temperature detecting means for detecting the dry-bulb temperature of the humidified air, the surface temperature of the test object, the dew point temperature of the humidified air supplied to the vicinity of the test object, and the vicinity of the test object 14. The apparatus according to claim 10, further comprising control means for controlling the humidified air dry bulb temperature to be supplied, the wind speed in the vicinity of the test object, and the strength of the cold air that applies cold heat to the test object. It is an environmental test apparatus as described in above.

  The environmental test apparatus of the present invention is an apparatus for realizing the environmental test method according to claim 7, and controls the air properties as in the case of claim 7.

  According to the fifteenth aspect of the present invention, the wind speed detecting means for detecting the wind speed in the vicinity of the DUT, the surface temperature detecting means for detecting the surface temperature of the DUT, and the dew point temperature of the air in the vicinity of the DUT. A dew point detecting means for detecting, and a near temperature detecting means for detecting the dry bulb temperature of air in the vicinity of the test object, the surface temperature of the test object, and the dew point temperature of the air in the vicinity of the test object, 14. The environment according to claim 10, further comprising control means for controlling a dry bulb temperature of air in the vicinity of the test object, a wind speed in the vicinity of the test object, and the strength of the cold air. Test equipment.

  An environmental test apparatus according to the present invention is an apparatus for realizing the environmental test method according to claim 8, and controls air properties as in the case of claim 8.

  In the invention described in claim 16, the object to be tested is an automobile, and cold air is blown onto the object to be tested from the front of the object to be tested, and the surface temperature of the object to be tested is reduced to around zero degrees Celsius or less. 16. The environmental test apparatus according to claim 9, wherein humidity air is supplied at a wind speed of 1 m / s or less so as to cover substantially the entire upper surface of the test object.

The environmental test apparatus according to the present invention is in line with the development purpose of the present invention, and can cause the automobile to frost and examine the influence of the frost on the automobile.
“Air at a predetermined temperature and humidity at a wind speed of 1 m / s or less” refers to a state where the absolute humidity in the vicinity of the DUT is gradually increased by utilizing gas diffusion or convection. In many cases, it does not artificially cause airflow or air mixing in the test chamber. As a result, the surface of the test object can be stably frosted.
“Supply so as to cover substantially the entire upper surface of the test object” refers to supplying supersaturated air from above in the test chamber in a state close to natural convection. That is, almost the same phenomenon as radiative cooling that occurs in cold regions can be reproduced in the test chamber.

  The invention described in claim 17 has fine particle control means for controlling the amount of minute liquid and minute solid contained in the air in the test chamber. Environmental test equipment.

  The environmental test apparatus of the present invention can reproduce a state closer to the natural environment. For example, it is possible to examine the influence of dust, mist, etc. on frost.

  ADVANTAGE OF THE INVENTION According to this invention, the environmental test method which can reproduce the phenomenon substantially the same as the frost which arises in nature, and the environmental test apparatus which can make a to-be-tested object frost can be provided.

1 is a schematic configuration diagram of an environmental test apparatus according to an embodiment of the present invention. It is an example of the time chart which shows the driving | running state of the environmental test apparatus of FIG. 1, Comprising: The humidity of the air produced | generated by the humidification means 6, the temperature of the cold wind of the air produced | generated by the cooling means 5, and a wind speed are shown. It is a schematic block diagram of the environmental test apparatus which concerns on the modification 1 of embodiment of this invention. It is a schematic block diagram of the environmental test apparatus from which the structure of a damper differs from the modification 1 of embodiment of this invention of FIG. It is a schematic block diagram of the environmental test apparatus which concerns on the modification 2 of embodiment of this invention. It is a schematic block diagram of the environmental test apparatus which concerns on the modification 3 of embodiment of this invention. It is a schematic block diagram of the environmental test apparatus which concerns on the modification 4 of embodiment of this invention. (A) is a schematic diagram of a frost formation process when the dew point temperature is above the freezing point, and (b) is a schematic diagram of a frost formation process when the dew point temperature is below the freezing point.

  A configuration of an environmental test method and an environmental test apparatus according to an embodiment of the present invention will be described with reference to the drawings. The description is intended to facilitate understanding of the embodiment, and the present invention should not be understood as being limited thereby.

First, frost formation conditions in nature will be described.
When a car is actually left outdoors in a cold region and frost attached to the surface of the car is observed, there are actually various shapes. Typical examples include frost adhering to the surface of an automobile in the form of dots and frost that forms a large branch-like crystal and spreads on the surface. These are expected to be different because of the different frost formation processes.
This will be described below.

For example, the surface of the automobile on the ground surface becomes lower than the dew point temperature of the outside air by the radiation cooling. Thereafter, the air in the sky flows near the surface of the automobile due to natural convection of wind or air, and the temperature of the air is lowered by being exposed to the low temperature of the automobile surface. As a result, near the surface of the automobile, the air falls below the dew point temperature, and the water vapor in the air undergoes a phase change, resulting in condensation and frost.
However, if the vehicle is separated from the surface of the vehicle by a certain distance, the surface temperature of the vehicle is completely unaffected and the temperature is the same as the outdoor temperature.

In other words, in the vicinity of the car surface, the car surface temperature, the air flow state, the air dew point temperature, the air dry bulb temperature, the air absolute humidity, the strength of the cold wind that gives cold to the car (wind speed, air volume, wind temperature) An unstable region (hereinafter referred to as an intermediate region) that is likely to cause dew condensation or frost formation due to the effect of air cleanliness or the like is formed.
In this intermediate region, the internal temperature and absolute humidity are not uniform, have a gradient toward the automobile surface, or are chaotic due to the influence of wind and natural convection, etc., and are expected to be non-uniform.

Explaining this situation in the case where the surface temperature of the automobile is below zero degrees Celsius, when high-humidity air approaches the vicinity of the automobile, the temperature drops and begins to form an intermediate region. When the temperature in the intermediate region falls below the dew point temperature of the air, the water vapor in the air is saturated and tends to condense. Further, when the vehicle approaches the vehicle, the temperature lowers and becomes supersaturated. Under such circumstances, when it comes into contact with dust in the air or foreign matter on the surface of the automobile, the phase changes depending on each state, condensing (condensation) or condensing (frosting), and finally forms frost on the automobile surface.
Further, as described above, when the water vapor phase changes in the vicinity of the automobile surface and the volume is reduced, the surrounding air pressure is lowered, and an air flow that sucks air in the sky is generated. It is thought to promote the formation of

Therefore, frost is formed in various processes depending on the air flow state, the temperature deviation between the intermediate region and other positions, the automobile surface temperature, and the relative humidity of the air.
When the flow state is intense, that is, the wind speed is high, air in a state where the phase change is not sufficiently completed collides with the surface of the automobile and may dew from a water droplet state or dew from a water vapor state.

In the case of natural convection close to windlessness, supersaturated or supercooled water vapor may condense with dust and foreign matter on the surface of the automobile as nuclei, and frost may grow with the condensation.
In addition, when the automobile surface temperature is sufficiently lower than near zero degrees Celsius, it becomes supersaturated or supercooled near the automobile surface, which collides with dust in the air and changes phase, forming and growing frost. Produce a wide variety of frosts.

In order to reproduce such a situation, as shown in the schematic diagram of the frost formation process in FIG. 8A, cold air is blown against the DUT 100 arranged in the test chamber 90, and the DUT is tested. The surface temperature of the object 100 is lowered to, for example, -5 degrees Celsius, and the temperature and humidity of air supplied from above in the test chamber 90 are 5 degrees Celsius, 3.4 g / m ³ (absolute humidity) ≈50% RH (degrees Celsius) Relative humidity at 5 degrees), the dew point temperature of the air is about -4.5 degrees Celsius.
When the air approaches the device under test 100 in a windless or light wind state, the temperature of the air becomes −4.5 degrees Celsius or less due to radiative cooling of the device under test 100, and the surface of the device under test 100, foreign matter, etc. The water vapor changes in phase and condenses, and frost 95 is formed on the DUT 100.
Alternatively, the air comes into contact with dust 99 in the air in the vicinity of the DUT 100, and the water vapor changes in phase and condenses and adheres to the DUT 100.
Under the above circumstances, it seems that the rate of phase change in contact with the surface of the DUT 100 is high.

As another example, as shown in the schematic diagram of the frost formation process in FIG. 8B, cold air is blown onto the DUT 100 arranged in the test chamber 90, and the surface temperature of the DUT 100 is measured. For example, the temperature and humidity of the air supplied from above in the test chamber 90 are 15 degrees Celsius, 11.5 g / m ³ (absolute humidity) ≈90% RH (relative humidity at 15 degrees Celsius) ), The dew point temperature of the air is about 14 degrees Celsius.
For this reason, the air collides with dust 99 or the like in the air to condense (condensation of the phase change) or become supersaturated water vapor while being cooled to near zero degrees Celsius or less.

Then, while being cooled to around −30 degrees Celsius, which is the surface temperature of the DUT 100, from near zero degrees Celsius or less, it collides with the dust 99 in the air near the DUT 100, condenses and falls. Alternatively, it contacts the device under test 100 in a supercooled state, and instantly condenses on the surface of the device under test 100.
In the above-described supercooled state, if the amount of dust 99 in the air is large, the rate of phase change in the air in the vicinity of the DUT 100 increases.

As described above, the surface temperature of the DUT 100, the dry bulb temperature and dew point temperature of the air supplied from above in the test chamber 90, the dew point temperature, dry bulb temperature and absolute humidity in the vicinity of the DUT 100, By individually controlling the strength of the cold air blown against the test object 100 (wind speed, air volume, air temperature), the frosting state on the test object 100 can be changed. Furthermore, it is also desirable to control the wind speed in the vicinity of the DUT 100 of air supplied from above in the test chamber 90.
By setting the parameter (variation factor) to a predetermined value, the air property can be controlled, and the frosting state on the surface of the DUT 100 can be freely controlled.

Then, the structure of the environmental test apparatus 1 which concerns on embodiment of this invention is explained in full detail.
In the present embodiment, as shown in FIG.
As shown in FIG. 1, the environmental test apparatus 1 includes a test chamber 2, a cooling chamber 3, a humidification chamber 4, a control device 65 (control means), a display 66, and a detection means 69.

  The test chamber 2 is a space inside the heat insulating box 31 surrounded by the heat insulating wall 30. The heat insulating wall 30 includes a heat insulating material 32. The environmental test apparatus 1 has a door (not shown) for taking in and out the DUT 20.

The cooling chamber 3 is provided in the test chamber 2 and has a blower pipe 10 and an intake pipe 12. The cooling chamber 3 and the test chamber 2 communicate with each other through a blower pipe 10 and an intake pipe 12. The end portion 11 of the blower tube 10 is widened and opened in a trumpet shape. An evaporator 44 and a blower 47 are disposed in the cooling chamber 3.
The cooling chamber 3 includes a cooling means 5 having a configuration indicated by a one-dot chain line. The cooling means 5 is for cooling the DUT 20 and includes a refrigeration circuit 40 (refrigeration cycle).
The refrigeration circuit 40 is a device for cooling the DUT 20 and includes a compressor 41, a condenser 42, an expansion valve 43, and an evaporator 44. Each device from the compressor 41 to the evaporator 44 is connected by a refrigerant pipe 45. A blower 47 is disposed in the vicinity of the evaporator 44, and a fan 48 is disposed in the vicinity of the condenser 42. Since the refrigeration circuit 40 is a known refrigeration cycle, a detailed description is omitted.

The humidification chamber 4 is provided outside the ceiling of the test chamber 2 and has a high humidity air supply port 13 and an intake pipe 14. The high humidity air supply port 13 and the intake pipe 14 are open on the ceiling surface of the test chamber 2. Here, the reason why the high humidity air supply port 13 is provided on the ceiling surface of the test chamber 2 is that the high humidity air supply port 13 is provided at the highest position of the test chamber 2, and the low humidity air is supplied from the high humidity air supply port 13. Is intended to increase the humidity in the test chamber 2 in a state close to natural convection and diffuse it in the vicinity of the device under test 20.
In the present embodiment, for the reasons described above, it is desirable to provide the high humidity air supply port 13 on the ceiling surface of the test chamber 2, but the present invention does not limit the position of the high humidity air supply port 13 to the ceiling surface. Absent.
However, it is desirable to provide the high humidity air supply port 13 as high as possible. It is desirable to provide at least a height higher than the total height of the automobile as a test object. More desirably, it is recommended that the height be 1.5 times or more the total height of the DUT, and ideally, the height be 3 times or more the total height of the DUT.

The humidifying chamber 4 includes a humidifying means 6 having a configuration indicated by a one-dot chain line. The humidifying means 6 is a device for sending low-temperature and high-humidity air into the test chamber 2, and includes a refrigeration circuit 50 (refrigeration cycle), a humidifier 60, and a heater 61.
In the humidification chamber 4, an evaporator 54, a heater 61, a blower 57, and a humidifier 60 are disposed.

Here, the temperature of the low-temperature and high-humidity air supplied from the humidification chamber 4 into the test chamber 2 is lower than the normal temperature, and is air adjusted to approximately less than 15 degrees Celsius. A more desirable temperature of the low temperature and high humidity air is around 10 degrees Celsius. The temperature of the low-temperature and high-humidity air is desirably 0 degrees Celsius or higher in order to prevent the entire test chamber 2 from being cooled to near zero degrees Celsius or lower.
The humidity of the low-temperature and high-humidity air is desirably such that it easily forms frost on the surface of the test object. From this point of view, it is recommended that the humidity of the low temperature and high humidity is 5.6 g / m ³ (absolute humidity) ≈60% RH (relative humidity at 10 degrees Celsius) or more.
However, because the test chamber is exposed to low temperatures during the test, the low-temperature and high-humidity humidity is 8.9 g / m ³ (absolute humidity) ≈ 95% RH (Celsius) in order to prevent dark condensation in the test chamber. (Relative humidity at 10 degrees) or less.

The refrigeration circuit 50 is installed to adjust the temperature in the humidification chamber 4 and includes a compressor 51, a condenser 52, an expansion valve 53, and an evaporator 54. Each device from the compressor 51 to the evaporator 54 is connected by a refrigerant pipe 55. A blower 57 is disposed in the vicinity of the evaporator 54, and a fan 58 is disposed in the vicinity of the condenser 52. Since the refrigeration circuit 50 is a known refrigeration cycle, a detailed description is omitted.
The humidifier 60 is installed to adjust the humidity in the humidification chamber 4. In addition, since the humidifier 60 is a well-known thing, detailed description is abbreviate | omitted.
The heater 61 is installed to adjust the temperature in the humidification chamber 4. In addition, since the heater 61 is a well-known thing, detailed description is abbreviate | omitted.

The control device 65 (control means) is for controlling the environmental test apparatus 1 and is a device capable of controlling the cooling means 5 and the humidifying means 6. Moreover, it is an apparatus which can control the temperature and humidity in the test chamber 2 by a program or the like.
The control device 65 is preferably composed of a programmable logic controller (PLC), a microcomputer (microcomputer), or the like.
In addition, a display device 66 is connected to the control device 65, and the operation state of the environmental test apparatus 1 is displayed on the display device 66.
The display unit 66 may be a display unit having a touch panel function, and may control the environmental test apparatus 1 by selecting an operation mode of the environmental test apparatus 1 through a touch panel operation.

The detection means 69 has a thermometer 70, a thermohygrometer 71, a thermohygrometer 72, and an anemometer 75, which are connected to the control device 65, and each measurement value is output to the control device 65. In addition, illustration of the wiring of the thermometer 70, the thermohygrometer 71, the thermohygrometer 72, the anemometer 75, and the control device 65 is omitted.
More specifically, the thermometer 70 is for measuring the surface temperature of the DUT 20, and is preferably composed of a temperature sensor such as a thermocouple.
The thermohygrometer 71 is for measuring the dry bulb temperature, the absolute humidity, the dew point temperature, and the like in the vicinity of the DUT 20, and the thermohygrometer 72 is a dry bulb near the center in the test chamber 2. It is for measuring temperature, absolute humidity, dew point temperature and the like. The thermohygrometer 71 and the thermohygrometer 72 are preferably devices capable of measuring dry bulb temperature, wet bulb temperature, dew point temperature, absolute humidity, etc., and output the values measured by the detection probe as digital signals. It consists of possible devices.
The anemometer 75 is for measuring the wind speed in the vicinity of the DUT 20, and is preferably composed of a hot-wire anemometer.

  Next, in the environmental test method using the environmental test apparatus 1 of the present embodiment, the process from the start of the test to the frost formation on the DUT 20 will be described with reference to FIG. In addition, each temperature and each humidity in the following description of the test method are obtained by detection and calculation by the control device 65 based on the detection result by the detection means 69.

FIG. 2 is a time chart showing operating states of the cooling means 5 and the humidifying means 6.
FIG. 2A shows the absolute humidity (g / m ³ ) of the low-temperature and high-humidity air sent into the test chamber 2 in the humidifying means 6 on the vertical axis. The low-temperature and high-humidity air is set to 10 degrees Celsius (° C.) and is blown into the test chamber 2 so that the wind speed is 1 m / s or less in the vicinity of the DUT 20. .

2B shows the temperature (° C.) of the cold air for cooling the DUT 20 in the cooling means 5 on the vertical axis, and FIG. 2C cools the DUT 20 in the cooling means 5. The wind speed (km / h) of the cold air for this is shown on the vertical axis.
In addition, the horizontal axis of Fig.2 (a)-(c) represents the time-axis (min).

2A to 2C show the test start, the low temperature arrival, and the completion of frost formation, respectively.
First, at a test start A, a dry cold air having a wind speed of 20 km / h and −35 degrees Celsius (° C.) produced by the cooling means 5 is blown toward the DUT 20 through the blower tube 10. At this time, the humidifying means 6 is not operated. Moreover, before the test is started, the inside of the test chamber 2 is set to a low humidity environment.

Subsequently, the blowing by the cooling means 5 is stopped at a low temperature reaching B 80 minutes after the start of the test A. At this time, the surface temperature of the device under test 20 is cooled to −35 degrees Celsius (° C.) below about zero degrees Celsius.
As a result, while the temperature of the air in the test chamber 2 is 10 degrees Celsius (° C.), only the temperature of the DUT 20 is lowered to −35 degrees Celsius (° C.) below zero degrees Celsius. That is, the reverse phenomenon of the temperature that is cooled below the upper side, which is a radiation cooling phenomenon that occurs in nature, is reproduced in the test chamber.
Simultaneously with the stop of air blowing by the cooling means 5, the absolute humidity of 8.5 g / m ³ ≈90% RH (relative humidity at 10 degrees Celsius), low temperature and high humidity air of 10 degrees Celsius (° C.) created by the humidifying means 6 Is supplied into the test chamber 2 from the humidification chamber 4 provided on the ceiling side of the test chamber 2 through the high humidity air supply port 13, diffuses in the test chamber 2, and reaches the periphery of the device under test 20.

After 90 minutes from the start of test A (10 minutes after reaching low temperature B), a dry cold wind of 5 km / h, produced by the cooling means 5 and at −30 degrees Celsius (° C.) was passed through the blower tube 10. The test object 20 is blown for 10 minutes and then stopped for 10 minutes. Thereafter, the blowing and stopping by the cooling means 5 are repeated every 10 minutes.
Supply low-temperature, high-humidity air with an absolute humidity of 8.5 g / m ³ ≈90% RH (relative humidity at 10 degrees Celsius) and 10 degrees Celsius (° C.) from the ceiling side of the test chamber 2 around the DUT 20. Subsequently, water vapor contained in the air around the DUT 20 adheres to the surface of the DUT 20 and is cooled to near zero degrees Celsius, freezes, and forms frost.

  Then, the frosting process is continued 320 minutes after the test start A (240 minutes after reaching the low temperature B), the frosting completion C is reached, and the cooling air 5 is blown by the cooling means 5 and the low temperature and high humidity by the humidifying means 6 is reached. Stop supplying air.

  As described above, according to the environmental test method and the environmental test apparatus 1 of the present embodiment, it is possible to create an environment in the environmental test apparatus 1 that is substantially the same as a cold region. Therefore, when the present invention is carried out, it is possible to reproduce substantially the same phenomenon as frost that occurs in nature, and it is possible to cause the device under test 20 (target object) to frost. That is, when the present invention is carried out, the test object can be easily frosted by the environmental test apparatus 1 without going to a cold region.

In the present embodiment, the environment test method employing the time chart shown in FIG. 2 is shown as an example, but the present invention is not limited to this. For example, the surface temperature of the DUT 20, the dry bulb temperature and dew point temperature of the air supplied from above in the test chamber 2, the dew point temperature, dry bulb temperature and absolute humidity in the vicinity of the DUT 20, and the cooling means 5. By individually controlling the strength of the cold air (wind speed, air volume, air temperature), the frosting state on the DUT 20 can be controlled. Furthermore, it is also desirable to control the wind speed in the vicinity of the DUT 100 of air supplied from above in the test chamber 20.
By setting the parameter (variation factor) to a predetermined value, the air properties can be controlled, and the frosting state on the surface of the DUT 20 can be freely controlled.

Although the environmental test apparatus 1 of this embodiment has the structure shown in FIG. 1, this invention is not limited to this. For example, as a modification of the present embodiment, a configuration as shown in FIGS. 3 to 7 may be adopted, and the same configuration numbers are used for the same components as the environmental test apparatus 1. .
Specifically, the environmental test apparatus 101 according to the first modification shown in FIG. 3 employs a configuration in which the humidifying chamber 4 is provided outside the ceiling of the test chamber 2, and a damper 80 is provided on the ceiling portion of the test chamber 2. It arrange | positions and the quantity of the air ventilated from the inside of the humidification chamber 4 in the test chamber 2 is adjusted with the opening degree of the damper 80, or the ventilation volume of the air blower 57.
In the humidification chamber 4, a partition plate 88 is disposed in the humidification chamber 4 and an air circulation channel 87 is provided. The air circulation channel 87 can circulate and adjust the air supplied to the test chamber 2 until the air reaches the target temperature, humidity, and wind speed.
Further, the blower 57 is controlled by the inverter 92 and can be operated at a low speed so as to be in a windless diffusion state in the vicinity of the DUT 20.
Instead of the damper 80, a curved damper 85 as shown in FIG.

5 employs a configuration in which the humidifying chamber 4 is provided outside the ceiling of the test chamber 2, and a slit 81 is provided on the ceiling of the test chamber 2. A plurality of fans 82 are arranged on the lower side, and the amount of air blown by the fans 82 is adjusted.
Note that the air blown by the fan 82 has a wind speed of 1 m / s or less, and the air in the humidifying chamber 4 is almost windless in the vicinity of the DUT 20.

  6 employs a configuration in which the humidification chamber 4 is provided in the test chamber 2, the humidification chamber 4 is disposed on the upper side of the cooling chamber 3, and the humidification chamber 4. The air inside is blown from the tip of the blower 57 directed to the ceiling and diffused.

  7 employs a configuration in which the humidification chamber 4 is provided in the test chamber 2, and the humidification chamber 4 is arranged on the ceiling side in the test chamber 2, so that the humidification chamber is provided. 4 is provided with a slit 81 to diffuse the air in the humidifying chamber 4 from a plurality of openings of the slit 81.

In the above-described embodiment, the example in which the blower tube 10 that is the blowout port of the cool air by the cooling unit 5 is provided at one place of the test chamber 2 is shown, but the present invention is not limited to this, and two places are provided. As described above, a cooling unit provided with the blower tube 10 or a cooling unit that blows air from the entire periphery of the DUT 20 may be employed.
In the above-described embodiment, an example in which the cooling means 5 is provided in the test chamber 2 has been described. However, the present invention is not limited to this, and the cooling means 5 is placed outside the test chamber 2 and the duct is arranged. It is good also as a structure which supplies cold wind by connecting.

  In the above-described embodiment, the example in which the automobile is the device under test 20 is shown. However, the present invention is not limited to this, and any vehicle can be used as the device under test. It is good also as a DUT.

In the above-described embodiment, an example in which the surface of the test object is “frosted” using the environmental test apparatus 1 has been described. However, the environmental test apparatus 1 can be used for applications other than frost formation. For example, you may use the environmental test apparatus of this invention for the test which attaches rain ice to the DUT 20, the test which attaches hoarfrost to the DUT 20, etc.
By the way, rain ice is a phenomenon in which a homogeneous and transparent ice layer generally adheres to features, and supercooled rain (freezing rain) etc. is a feature whose temperature is slightly higher than zero degrees Celsius or zero degrees Celsius. Frozen in contact with
Rime is a phenomenon in which a white or translucent ice layer adheres to a feature, and is a collective term for three types of tree frost, tree ice, and coarse ice.
Tree frost is mainly composed of ice crystals produced by condensation of water vapor, and crystal forms such as needle shapes, flat shapes, and cup shapes are often recognized.
Tree ice is white, translucent, brittle ice that is mainly formed by spraying supercooled mists or the like onto features.
Crude ice is said to be made in the same manner as tree ice, and is a translucent or transparent ice mass.

  In the present embodiment, the environment test method employing the time chart shown in FIG. 2 is shown as an example, but the present invention is not limited to this. For example, the operation of keeping the inside of the humidifying chamber 4 at a predetermined humidity by the humidifying means 6 in advance may be performed, and the air blowing into the test chamber 2 may be started simultaneously with the stop of the cooling means 5.

  In this embodiment, although the ventilation by the cooling means 5 was shown as an example, this invention is not limited to this. For example, the DUT may be cooled using a plurality of Peltier elements.

DESCRIPTION OF SYMBOLS 1 Environmental test apparatus 2 Test chamber 3 Cooling chamber 4 Humidification chamber 5 Cooling means 6 Humidification means 20 Test object 65 Control apparatus (control means)
95 Frost 99 Dust 100 DUT 101 Environmental test equipment 102 Environmental test equipment 103 Environmental test equipment 104 Environmental test equipment

Claims (17)

  Place the DUT in the test chamber of the environmental test equipment, lower the surface temperature of the DUT in the test room to below zero degrees Celsius, and then increase the absolute humidity at least near the DUT. An environmental testing method characterized in that water vapor in the air is phase-changed on the surface of an object and / or in the vicinity thereof to cause frost on the surface of the object.   Supply air whose dew point temperature is equal to or higher than the surface temperature of the DUT so that it is in a no-wind state or a breeze state with a wind speed of 4 m / s or less near the DUT to increase at least the absolute humidity near the DUT. The environmental test method according to claim 1.   The environmental test method according to claim 1 or 2, wherein the surface temperature of the object to be tested is lowered to a temperature lower than or equal to about zero degrees Celsius and lower than the average temperature in the placed test room.   Cool air is blown over a certain period of time to reduce the surface temperature of the DUT to near zero degrees Celsius, then the cold air blowing is temporarily or permanently stopped, and then at least near the DUT. The environmental test method according to claim 1, wherein the absolute humidity is increased so that the dew point temperature of the air becomes equal to or higher than the surface temperature of the test object.   Cool air is blown over a certain period of time to reduce the surface temperature of the DUT to near zero degrees Celsius, then the amount of cold given to the DUT per unit time is reduced, and then at least the DUT The environmental test method according to claim 1, wherein the absolute humidity is increased so that the dew point temperature of the air in the vicinity becomes equal to or higher than the surface temperature of the test object.   The air having a dew point temperature equal to or higher than the surface temperature of the DUT is supplied to the inside of the test room from above the DUT so that there is no wind or a breeze in the vicinity of the DUT. 6. The environmental test method according to any one of 5 to 5.   Supplying air containing humidity to the vicinity of the DUT to increase the absolute humidity in the vicinity of the DUT, the surface temperature of the DUT and the dry bulb of the air supplied to the vicinity of the DUT The environmental test method according to any one of claims 4 to 6, wherein the temperature and dew point temperature, the wind speed in the vicinity of the DUT, and the strength of the cold air that gives cold heat to the DUT can be controlled. .   The surface temperature of the DUT, the dry bulb temperature of the air in the vicinity of the DUT, the dew point of the air in the vicinity of the DUT, the wind speed in the vicinity of the DUT, and the cold air that gives the DUT cold heat The environmental test method according to any one of claims 4 to 6, wherein the strength of the environmental test can be controlled.   Absolute humidity should be adjusted so that the dew point temperature of the air near the DUT is equal to or higher than the surface temperature of the DUT. Humidifying means for increasing the temperature, lowering the surface temperature of the DUT by the cooling means to near zero degrees Celsius or less, changing the phase of the water vapor in the air at and / or in the vicinity of the DUT, An environmental test apparatus characterized by having the ability to frost on the surface of an object.   The environmental testing apparatus according to claim 9, wherein the cooling unit is configured to reduce the surface temperature of the test object by blowing cold air onto the test object.   The cooling means and the humidifying means each have a separate blowing means, wherein the humidifying means generates humidified air, and the humidifying air is blown to the vicinity of the test object by the blowing means. The environmental test apparatus according to 9 or 10.   The amount of cooling heat given to the DUT per unit time can be increased or decreased by changing the strength of the cold air or by intermittently blowing cold air to the DUT. The environmental test apparatus according to 10 or 11.   There is a high-humidity air supply port above the test chamber. Air from the high-humidity air supply port is supplied to the test chamber with air of an absolute humidity that has a dew point temperature equal to or higher than the surface temperature of the DUT. The environmental test apparatus according to claim 9, wherein the humidity is increased.   The humidifying means generates humidified air and supplies the humidified air to the vicinity of the test object. The wind speed detecting means for detecting the wind speed near the test object and the surface for detecting the surface temperature of the test object. Temperature detection means, dew point detection means for detecting the dew point temperature of humidified air supplied in the vicinity of the test object by the humidification means, and dry bulb temperature of the humidified air supplied in the vicinity of the test object by the humidification means Supply air temperature detecting means, and the surface temperature of the test object, the dew point temperature of the humidified air supplied to the vicinity of the test object, and the humidified air dry bulb temperature supplied to the vicinity of the test object, 14. The environmental test apparatus according to claim 10, further comprising control means for controlling a wind speed in the vicinity of the device under test and a strength of the cold air that applies cold heat to the device under test.   Wind speed detecting means for detecting the wind speed in the vicinity of the DUT, surface temperature detecting means for detecting the surface temperature of the DUT, dew point detecting means for detecting the dew point temperature of air in the vicinity of the DUT, and the DUT A temperature detecting means for detecting a dry bulb temperature of air in the vicinity of the object, the surface temperature of the object to be tested, the dew point temperature of the air in the vicinity of the object to be tested, 14. The environmental test apparatus according to claim 10, further comprising control means for controlling the bulb temperature, the wind speed in the vicinity of the object to be tested, and the strength of the cold air.   The test object is an automobile, and cool air is blown onto the test object from the front of the test object to bring the surface temperature of the test object to near zero degrees Celsius or less, and then air at a predetermined temperature and humidity is 1 m / s or less. 16. The environmental test apparatus according to claim 9, wherein the environmental test apparatus is supplied so as to cover substantially the entire upper surface of the test object with the wind speed.   The environmental test apparatus according to any one of claims 9 to 16, further comprising fine particle control means for controlling the amount of minute liquid and minute solid contained in the air in the test chamber.

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