Vehicle air conditioning system

Abstract

To provide a vehicle air conditioning system capable of reducing the size of the system and achieving power saving while maintaining its humidity control function.SOLUTION: A vehicle air conditioning system includes: an air conditioning duct through which air from a passenger compartment or the outside of a vehicle can flow; a ventilation fan disposed in the air conditioning duct; and a humidity controlling device 30 including a honeycomb structure 31 having an outer peripheral wall and partition walls 35 disposed on an inner side of the outer peripheral wall and defining a plurality of cells 34 each of which extends from a first end face 33a to a second end face 33b to form an air passage, and a moisture absorbing layer 36 formed on surfaces of the partition walls 35, the humidity controlling device 30 disposed in the air conditioning duct on a downstream side of the ventilation fan.SELECTED DRAWING: Figure 2A

Description

[Technical Field]

[0001] The present invention relates to a vehicle air conditioning system. [Background technology]

[0002] There is a growing demand for improved cabin environments in automobiles and other vehicles. Specific examples of such demands include humidity control within the vehicle cabin. Ventilation is an effective solution to meet these demands, but ventilation can significantly reduce heating energy in winter, resulting in reduced energy efficiency. This energy loss, particularly in battery electric vehicles (BEVs), poses a significant problem of reduced driving range.

[0003] As a method for solving the above problem, Patent Document 1 proposes a vehicle air conditioning system (vehicle air purification system) that includes: a first flow path that includes a first heating device, a first adsorption block, and a first flow path switching mechanism and is connected to the vehicle cabin; a second flow path that includes a second heating device, a second adsorption block, and a second flow path switching mechanism and is connected to the vehicle cabin; a blower that circulates air from the vehicle cabin; an air distribution mechanism that distributes the air flowing from the vehicle cabin to the first flow path and the second flow path; and a control device that controls each component at a timing that prevents air from flowing into the vehicle cabin from the flow path that is desorbing the substance to be purified when switching the flow paths that carry air that has passed through the first adsorption block and air that has passed through the second adsorption block. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2020-104774 Summary of the Invention [Problem to be solved by the invention]

[0005] The vehicle air conditioning system of Patent Document 1 has adsorption blocks arranged in two flow paths (first and second flow paths), with the flow paths further branching downstream of the adsorption blocks and valves (air distribution mechanisms) at the branching points of each flow path. A vehicle air conditioning system with this configuration can reliably remove target substances such as water vapor (moisture) by alternately adsorbing them using the adsorption blocks arranged in each flow path, but the system size increases due to the large number of flow paths (pipes) and valves. Furthermore, because the air flowing through each flow path must always pass through the adsorption blocks, this places a heavy load on the ventilator, resulting in increased power consumption.

[0006] The present invention has been made to solve the above problems, and has an object to provide a vehicle air conditioning system that can be made smaller and more energy-efficient while maintaining humidity control function. [Means for solving the problem]

[0007] The present inventors have conducted extensive research into vehicle air conditioning systems equipped with humidity control devices, and have discovered that a specific structure can ensure humidity control function without providing humidity control devices in each flow path, thereby enabling miniaturization and power saving, leading to the completion of the present invention. That is, the present invention is exemplified as follows.

[0008] <1> an air conditioning duct through which air from the vehicle compartment or outside the vehicle can circulate; a fan disposed in the air conditioning duct; a honeycomb structure having an outer peripheral wall, and partition walls disposed inside the outer peripheral wall and defining a plurality of cells that serve as the air flow path extending from a first end face to a second end face; and a humidity control device having a moisture absorption layer provided on a surface of the partition wall, the humidity control device being disposed in the air conditioning duct downstream of the fan; A vehicle air conditioning system comprising: the air conditioning duct is branched downstream of the fan into a first flow path in which the humidity control device is disposed and a second flow path in which the humidity control device is not disposed, the first flow path further branches into a third flow path that causes the air to flow into the vehicle compartment and a fourth flow path that causes the air to flow out of the vehicle; a second valve capable of adjusting the amount of air that flows in is disposed in the second flow path; a third valve capable of switching the flow of air between the third flow path and the fourth flow path is disposed at a branch point between the third flow path and the fourth flow path;

[0009] <2> A first valve capable of adjusting the inflow amount of the air is disposed in the first flow path upstream of the humidity control device. <1> The vehicle air conditioning system according to claim 1.

[0010] <3> Further comprising a control unit capable of controlling the first valve, the second valve, and the third valve. <2> The vehicle air conditioning system according to claim 1.

[0011] <4> the control unit controls the opening degrees of the first valve and the second valve when the humidity control device is in a moisture absorption mode or a regeneration mode. <3> The vehicle air conditioning system according to claim 1.

[0012] <5> The flow rate of the air generated by the fan is 3 m 3 / min or less, the control unit controls the ratio of the opening degree of the second valve to the opening degree of the first valve to be 0.5 or less. <4> The vehicle air conditioning system according to claim 1.

[0013] <6> The flow rate of the air generated by the fan is 3 m 3 / min, the control unit controls the ratio of the opening degree of the second valve to the opening degree of the first valve to be 0.3 or more. <4> or <5> The vehicle air conditioning system according to claim 1.

[0014] <7> The minimum cross-sectional area of ​​the second flow path is larger than the minimum cross-sectional area of ​​the first flow path, and the minimum cross-sectional area of ​​the fourth flow path is smaller than the minimum cross-sectional area of ​​the third flow path. <1> ~ <6> 10. A vehicle air conditioning system according to claim 9, wherein:

[0015] <8> The minimum cross-sectional area of ​​the second flow path is at least twice the minimum cross-sectional area of ​​the third flow path. <7> The vehicle air conditioning system according to claim 1.

[0016] <9> The minimum cross-sectional area of ​​the third flow path is four times or more the minimum cross-sectional area of ​​the fourth flow path. <7> or <8> The vehicle air conditioning system according to claim 1.

[0017] <10> In the honeycomb structure, at least the partition walls are made of a material having PTC properties. <1> ~ <9> 10. A vehicle air conditioning system according to claim 9, wherein:

[0018] <11> The humidity control device further includes a pair of electrodes provided on the first end face and the second end face of the honeycomb structure, or on the outer peripheral wall of the honeycomb structure that is parallel to the cell extension direction. <1> ~ <10> 10. A vehicle air conditioning system according to claim 9, wherein: [Effects of the Invention]

[0019] According to the present invention, it is possible to provide a vehicle air conditioning system that can be made smaller and consume less power while still maintaining a humidity control function. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a schematic diagram illustrating the overall configuration of a vehicle air conditioning system according to a first embodiment of the present invention. [Figure 2A] 1 is a schematic diagram of a cross section parallel to the flow path direction of a humidity control device used in a vehicle air conditioning system according to a first embodiment of the present invention. [Figure 2B] 2B is a schematic cross-sectional view of the humidity control device of FIG. 2A taken along line aa'. FIG. [Figure 3] FIG. 1 is a schematic diagram illustrating the overall configuration of a vehicle air conditioning system according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0021] The vehicle air conditioning system of the present invention includes an air conditioning duct through which air can flow from the vehicle interior or outside the vehicle; a fan disposed in the air conditioning duct; a honeycomb structure having an outer peripheral wall and partition walls disposed inside the outer peripheral wall and defining a plurality of cells that serve as air flow paths extending from a first end face to a second end face; and a humidity control device disposed in the air conditioning duct downstream of the fan, the humidity control device having a moisture absorbing layer provided on the surface of the partition wall. The air conditioning duct branches downstream of the fan into a first flow path in which the humidity control device is disposed and a second flow path in which the humidity control device is not disposed. The first flow path further branches into a third flow path that introduces air into the vehicle interior and a fourth flow path that introduces air to the outside of the vehicle. A second valve capable of adjusting the amount of air that flows in is disposed in the second flow path. A third valve capable of switching the air flow between the third flow path and the fourth flow path is disposed at the branch point between the third flow path and the fourth flow path. In the vehicle air conditioning system of the present invention having such a configuration, the humidity control function can be sufficiently ensured by the humidity control device disposed in the first flow path, so there is no need to dispose a humidity control device in the second flow path. This reduces the number of flow paths and valves, and also reduces the load on the ventilator, making it possible to reduce the system size and power consumption. In this specification, the terms "upstream side" and "downstream side" are based on the flow of air circulating through the vehicle air conditioning system.

[0022] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the following embodiments, and it should be understood that modifications and improvements made to the following embodiments based on the ordinary knowledge of those skilled in the art without departing from the spirit of the present invention are also within the scope of the present invention.

[0023] <Embodiment 1> The vehicle air conditioning system according to the first embodiment of the present invention can be suitably used in various vehicles such as automobiles. Examples of vehicles include, but are not limited to, automobiles and trains. Examples of automobiles include, but are not limited to, gasoline-powered vehicles, diesel-powered vehicles, gas-fueled vehicles using CNG (compressed natural gas) or LNG (liquefied natural gas), fuel cell vehicles, electric vehicles, and plug-in hybrid vehicles. The vehicle air conditioning system according to the first embodiment of the present invention can be suitably used in particular in vehicles without internal combustion engines, such as electric vehicles and trains.

[0024] Fig. 1 is a schematic diagram of the overall configuration of a vehicle air conditioning system according to embodiment 1 of the present invention. Fig. 2A is a schematic diagram of a cross section parallel to the flow path direction of a humidity control device used in the vehicle air conditioning system according to embodiment 1 of the present invention. Fig. 2B is a schematic diagram of a cross section taken along line a-a' in the humidity control device of Fig. 2A.

[0025] As shown in FIG. 1, the vehicle air conditioning system according to the first embodiment of the present invention includes an air conditioning duct 10, a ventilator 20, a humidity control device 30, and a control unit .

[0026] Air from the vehicle interior or outside can flow through the air conditioning duct 10. The air conditioning duct 10 branches downstream of the ventilator 20 into a first flow path 11 in which a humidity control device 30 is disposed and a second flow path 12 in which the humidity control device 30 is not disposed. The first flow path 11 further branches into a third flow path 13 that allows air to flow into the vehicle compartment and a fourth flow path 14 that allows air to flow out of the vehicle. The third flow path 13 joins with the second flow path 12 downstream to form a fifth flow path 15 that returns to the vehicle interior. If necessary, known components (not shown) used for heating and cooling, such as an evaporator or a condenser, may be arranged in the fifth flow path 15.

[0027] A first valve 51 is disposed in the first flow path 11 on the upstream side of the humidity control device 30. The first valve 51 is a valve that can adjust the amount of air that flows into the humidity control device 30. The first valve 51 is not particularly limited as long as it has the above-mentioned function, and a known valve such as a tamper valve or a butterfly valve can be used.

[0028] A second valve 52 is disposed in the second flow path 12. The second valve 52 is a valve that can adjust the amount of air that flows into the second flow path 12. The position of the second valve 52 is not particularly limited as long as it is within the second flow path 12, and it may be located either upstream or downstream of the second flow path 12. The second valve 52 is not particularly limited as long as it has the above-mentioned function, and a known valve such as a tamper valve or a butterfly valve can be used.

[0029] A third valve 53 is disposed at the branch point between the third flow path 13 and the fourth flow path 14. The third valve 53 is a valve capable of switching the flow of air between the third flow path 13 and the fourth flow path 14. The third valve 53 is not particularly limited as long as it has the above-described function, and a known valve can be used. Specifically, the third valve 53 may be any valve that is electrically driven and has the function of switching the flow path, and a solenoid valve, an electric valve, or the like can be used. For example, the third valve 53 includes an open / close door supported on a rotating shaft and an actuator such as a motor that rotates the rotating shaft. The actuator can be configured to be controllable by the control unit 40.

[0030] The humidity control device 30 is disposed in the air conditioning duct 10 (specifically, the first flow path 11) downstream of the fan 20. The number of humidity control devices 30 disposed in the air conditioning duct 10 may be one or more. When multiple humidity control devices 30 are provided, they may be disposed in parallel or in series with respect to the flow of air circulating inside the air conditioning duct 10. 2A and 2B, the humidity control device 30 includes a honeycomb structure 31 having an outer peripheral wall 32 and partition walls 35 disposed inside the outer peripheral wall 32 to define a plurality of cells 34 that serve as air flow paths extending from a first end face 33a to a second end face 33b, and a moisture absorbing layer 36 provided on the surface of the partition wall 35. The honeycomb structure 31 may also be provided with a pair of electrodes 37a, 37b and terminals 38 connected to the pair of electrodes 37a, 37b.

[0031] The control unit 40 can control the fan 20, the humidity control device 30, and each valve (first valve 51, second valve 52, and third valve 53). Specifically, the control unit 40 is electrically connected to the fan 20, the humidity control device 30, and each valve, and can control the fan 20, the humidity control device 30, and each valve according to instructions from the control unit 40. In particular, the fan 20 can control the flow rate of air flowing through the air conditioning duct 10 by controlling the rotation speed of the fan 20 according to instructions from the control unit 40.

[0032] In a vehicle air conditioning system having the above-described structure, air can be circulated through the first flow path 11 to reduce the moisture content in the air in the humidity control device 30, and the air can be dehumidified by circulating the air through the third flow path 13. The mode of the humidity control device 30 in this case is called the "moisture absorption mode." Furthermore, the humidity control device 30 can be regenerated by heating the humidity control device 30 while circulating air through the first flow path 11 to desorb the moisture adsorbed by the humidity control device 30, and then flowing the air containing the moisture through the fourth flow path 14 and discharging it outside the vehicle. The mode of the humidity control device 30 in this case is called a "regeneration mode." Furthermore, by circulating air through the second flow path 12, it is possible to blow air into the vehicle interior.

[0033] The control unit 40 can control the opening degrees of the first valve 51 and the second valve 52 when the humidity control device 30 is in the moisture absorption mode or the regeneration mode. By controlling the opening degrees of the first valve 51 and the second valve 52, air can be circulated through the humidity control device 30 at a flow rate appropriate for each mode while air is allowed to flow into the vehicle cabin. Here, the "opening degree" of each valve in this specification means the cross-sectional area of ​​the passage through which air flows expressed as a percentage, assuming that the cross-sectional area of ​​the passage through which air flows when each valve is fully open is 100%.

[0034] The flow rate of air generated by the ventilator 20 is 3 m 3 / min or less, the control unit 40 preferably controls the ratio of the opening degree of the second valve 52 to the opening degree of the first valve 51 to 0.5 or less. By controlling the opening ratio within this range, it is possible to circulate air at an appropriate flow rate through the first flow path 11. This makes it easier to perform the adsorption (dehumidification) process by the humidity control device 30 and the regeneration process of the humidity control device 30. In particular, by performing the above control during the regeneration process of the humidity control device 30, it is possible to increase the efficiency of the regeneration process of the humidity control device 30. In this case, the lower limit of the ratio of the opening degrees is not particularly limited, and may be 0 (a state in which the second valve 52 is closed).

[0035] In addition, the flow rate of air generated by the ventilator 20 is 3 m 3 / min, it is preferable that the control unit 40 controls the ratio of the opening of the second valve 52 to the opening of the first valve 51 to 0.3 or more. By controlling the opening ratio within this range, it is possible to circulate air at an appropriate flow rate through the first flow path 11. This makes it easier to perform the adsorption (dehumidification) process by the humidity control device 30 and the regeneration process of the humidity control device 30. In particular, by performing the above control during the adsorption process by the humidity control device 30, it is possible to increase the efficiency of the adsorption process by the humidity control device 30. In this case, the upper limit of the ratio of the opening degrees is not particularly limited, but is typically 1.0 or less, and preferably 0.8 or less.

[0036] Other details of each component of the vehicle air conditioning system will be described below.

[0037] (1. Air conditioning duct 10) The air conditioning duct 10 is a flow path through which air can flow. The air conditioning duct 10 includes the first flow path 11, the second flow path 12, the third flow path 13, the fourth flow path 14, and the fifth flow path 15 as described above. The material of the air conditioning duct 10 is not particularly limited, but is preferably a metal from the viewpoint of manufacturability. Examples of materials for the air conditioning duct 10 include stainless steel, titanium alloy, copper alloy, aluminum alloy, brass, etc. Among these, stainless steel is preferred because of its high durability, reliability, and low cost.

[0038] (2. Ventilator 20) The ventilator 20 is a device for circulating air from the vehicle interior or the outside of the vehicle. The ventilator 20 is not particularly limited, and a commercially available ventilator can be used. Furthermore, the fan 20 is electrically connected to the control unit 40, and can control the amount of air by adjusting the rotation speed in accordance with instructions from the control unit 40.

[0039] (3. Humidity Control Device 30) (3-1. Honeycomb structure 31) The shape of the honeycomb structure 31 is not particularly limited. For example, the outer shape of a cross section perpendicular to the flow path direction (the direction in which the cells 34 extend) of the honeycomb structure 31 can be a polygon such as a quadrangle (rectangle, square), pentagon, hexagon, heptagon, or octagon, a circle, or an oval shape (egg, ellipse, oval, rounded rectangle, etc.). The end faces (first end face 33a and second end face 33b) have the same shape as the cross section. When the cross section and end faces are polygonal, the corners may be chamfered.

[0040] The shape of the cells 34 is not particularly limited, but may be a polygon such as a square, pentagon, hexagon, heptagon, or octagon, a circle, or an oval in a cross section perpendicular to the flow path direction of the honeycomb structure 31. These shapes may be used alone or in combination of two or more. Among these shapes, a square or hexagon is preferable. By providing cells 34 of such a shape, pressure loss during air flow can be reduced.

[0041] The honeycomb structure 31 may be a honeycomb bonded body having a plurality of honeycomb segments and a bonding layer bonding the outer peripheral side surfaces of the plurality of honeycomb segments together. By using the honeycomb bonded body, it is possible to increase the total cross-sectional area of ​​the cells 34, which is important for ensuring the air flow rate, while suppressing the occurrence of cracks. The bonding layer can be formed using a bonding material. The bonding material is not particularly limited, but may be a ceramic material. A paste made by adding a solvent such as water to the raw material can be used. The bonding material may contain a material having PTC properties, or may contain the same material as the outer wall 32 and the partition walls 35. In addition to the role of bonding the honeycomb segments together, the bonding material can also be used as an outer coating material after bonding the honeycomb segments.

[0042] From the viewpoints of ensuring the strength of the honeycomb structure 31, reducing pressure loss when air passes through the cells 34, ensuring the amount of functional material carried, and ensuring the contact area with the air flowing within the cells 34, it is desirable to suitably combine the thickness of the partition walls 35, the cell density, and the cell pitch (or the opening ratio of the cells 34). In this specification, cell density is a value obtained by dividing the number of cells by the area of ​​one end face (first end face 33a or second end face 33b) of the honeycomb structure 31 (the total area of ​​the partition walls 35 and cells 34 excluding the outer wall 32). In this specification, the cell pitch refers to a value determined by the following calculation: First, the area per cell is calculated by dividing the area of ​​one end face (first end face 33a or second end face 33b) of the honeycomb structure 31 (the total area of ​​the partition walls 35 and cells 34 excluding the outer peripheral wall 32) by the number of cells. Next, the square root of the area per cell is calculated, and this is defined as the cell pitch. In this specification, the opening ratio of the cells 34 is a value obtained by dividing the total area of ​​the cells 34 partitioned by the partition walls 35 in a cross section perpendicular to the flow direction of the honeycomb structure 31 by the area of ​​one end face (the first end face 33a or the second end face 33b) (the total area of ​​the partition walls 35 and the cells 34 excluding the outer peripheral wall 32). Note that when calculating the opening ratio of the cells 34, the pair of electrodes 37a, 37b and the moisture absorption layer 36 are not taken into consideration.

[0043] In an advantageous embodiment from the viewpoint of carrying a sufficient amount of functional material, the thickness of the partition wall 35 is 0.300 mm or less, and the cell density is 100 cells / cm. 2 In a preferred embodiment, the thickness of the partition walls 35 is 0.200 mm or less, and the cell density is 70 cells / cm. 2 In a more preferred embodiment, the thickness of the partition walls 35 is 0.130 mm or less, and the cell density is 65 cells / cm. 2 or less, and the cell pitch is 1.3 mm or more.

[0044] From the viewpoint of ensuring the strength of the honeycomb structure 31 and keeping the electrical resistance low, the lower limit of the thickness of the partition walls 35 is preferably 0.010 mm or more, more preferably 0.020 mm or more, and even more preferably 0.030 mm or more. From the viewpoint of ensuring the strength of the honeycomb structure 31, keeping the electrical resistance low, and increasing the surface area to promote reaction, adsorption, and desorption, the lower limit of the cell density is 30 cells / cm. 2 Preferably, 35 cells / cm or more. 2 More preferably, 40 cells / cm or more. 2 More preferably, it is equal to or greater than this. From the viewpoint of ensuring the strength of the honeycomb structure 31, maintaining low electrical resistance, and increasing the surface area to promote reaction, adsorption, and desorption, the upper limit of the cell pitch is preferably 2.0 mm or less, more preferably 1.8 mm or less, and even more preferably 1.6 mm or less.

[0045] In an advantageous embodiment from the viewpoint of achieving both a reduction in pressure loss and a maintenance of strength, the thickness of the partition wall 35 is 0.08 to 0.36 mm, and the cell density is 2.54 to 140 cells / cm. 2 In a preferred embodiment, the thickness of the partition walls 35 is 0.09 to 0.35 mm, and the cell density is 15 to 100 cells / cm. 2 In a more preferred embodiment, the thickness of the partition walls 35 is 0.14 to 0.30 mm, and the cell density is 20 to 90 cells / cm. 2 The aperture ratio of the cell 34 is 0.85 or more.

[0046] From the viewpoint of ensuring the strength of the honeycomb structure 31, the upper limit of the opening ratio of the cells 34 is preferably 0.94 or less, more preferably 0.92 or less, and further preferably 0.90 or less.

[0047] The thickness of the peripheral wall 32 is not particularly limited, but is preferably determined based on the following points: First, from the viewpoint of reinforcing the honeycomb structure 31, the thickness of the peripheral wall 32 is preferably 0.05 mm or more, more preferably 0.06 mm or more, and even more preferably 0.08 mm or more. On the other hand, from the viewpoint of increasing the electrical resistance to suppress the initial current and reducing the pressure loss during air circulation, the thickness of the peripheral wall 32 is preferably 1.0 mm or less, more preferably 0.5 mm or less, even more preferably 0.4 mm or less, and even more preferably 0.3 mm or less. In this specification, the thickness of the peripheral wall 32 refers to the length in the normal direction of the side surface of the honeycomb structure 31 from the boundary between the peripheral wall 32 and the outermost cell 34 or partition wall 35 in a cross section perpendicular to the flow direction of the honeycomb structure 31.

[0048] The length of the honeycomb structure 31 in the flow path direction and the cross-sectional area perpendicular to the flow path direction are not particularly limited and may be adjusted according to the required size of the humidity control device 30. For example, when used in a compact humidity control device 30 while ensuring a predetermined function, the honeycomb structure 31 has a length in the flow path direction of 2 to 20 mm and a cross-sectional area perpendicular to the flow path direction of 10 cm. 2 The upper limit of the cross-sectional area perpendicular to the flow path direction is not particularly limited, but may be, for example, 300 cm 2 The following is the result.

[0049] The partition walls 35 constituting the honeycomb structure 31 are made of a material that can generate heat when electricity is applied, and specifically, preferably made of a material having PTC characteristics. If necessary, the peripheral wall 32 may also be made of a material having PTC characteristics, like the partition walls 35. This configuration allows the moisture absorption layer 36 to be directly heated by heat transfer from the heat-generating partition walls 35 (and the peripheral wall 32, if necessary). Furthermore, materials having PTC characteristics have the property that, when their temperature rises and exceeds the Curie point, their resistance value rises sharply, making it difficult for electricity to flow through them. Therefore, when the partition walls 35 (and the peripheral wall 32, if necessary) reach a high temperature, the current flowing through them is limited, thereby suppressing excessive heat generation in the honeycomb structure 31. This also makes it possible to suppress thermal deterioration of the moisture absorption layer 36 due to excessive heat generation.

[0050] From the viewpoint of obtaining an appropriate heat generation, the lower limit of the volume resistivity at 25°C of the material having PTC characteristics is preferably 0.5 Ω cm or more, more preferably 1 Ω cm or more, and even more preferably 5 Ω cm or more. In this specification, the volume resistivity at 25°C of the material having PTC characteristics is measured in accordance with JIS K6271:2008.

[0051] From the viewpoint of being able to generate heat when electrically applied and having PTC characteristics, the outer peripheral wall 32 and the partition walls 35 are preferably made of a material whose main component is barium titanate (BaTiO3). Furthermore, this material is more preferably a ceramic made of a material whose main component is barium titanate (BaTiO3)-based crystal particles in which part of the Ba is substituted with a rare earth element. In this specification, the term "main component" refers to a component that accounts for more than 50 mass% of the total components. The content of BaTiO3-based crystal particles can be determined by fluorescent X-ray analysis. Other crystal particles can also be measured using a similar method.

[0052] The composition formula of BaTiO3-based crystal particles in which part of Ba is replaced by rare earth elements is (Ba 1-x A x )TiO3, where A represents one or more rare earth elements and x is 0.0001≦x≦0.010. A is not particularly limited as long as it is a rare earth element, but is preferably one or more selected from the group consisting of La, Ce, Pr, Nd, Eu, Gd, Dy, Ho, Er, Y, and Yb, and more preferably La. x is preferably 0.001 or more, more preferably 0.0015 or more, from the viewpoint of preventing the electrical resistance at room temperature from becoming too high. On the other hand, x is preferably 0.009 or less, from the viewpoint of preventing the electrical resistance at room temperature from becoming too high due to insufficient sintering. The content of BaTiO3-based crystal particles in the ceramic, in which Ba is partially substituted with a rare earth element, is not particularly limited as long as it is an amount that serves as the main component, but is preferably 90 mass% or more, more preferably 92 mass% or more, and even more preferably 94 mass% or more. The upper limit of the content of BaTiO3-based crystal particles is not particularly limited, but is generally 99 mass%, preferably 98 mass%.

[0053] From the viewpoint of reducing environmental impact, it is desirable that the materials used for the outer peripheral wall 32 and the partition wall 35 be substantially free of lead (Pb). Specifically, the Pb content of the outer peripheral wall 32 and the partition wall 35 is preferably 0.01% by mass or less, more preferably 0.001% by mass or less, and even more preferably 0% by mass. A low Pb content allows, for example, air heated by contact with the partition wall 35 during heat generation to be safely applied to living organisms such as humans. The Pb content of the outer peripheral wall 32 and the partition wall 35, calculated as PbO, is preferably less than 0.03% by mass, more preferably less than 0.01% by mass, and even more preferably 0% by mass. The lead content can be determined by ICP-MS (inductively coupled plasma mass spectrometry).

[0054] The Curie points of the materials constituting the outer peripheral wall 32 and the partition walls 35 are preferably in the temperature range at which the resistance value becomes at least twice the resistance value at room temperature (25°C). If the Curie points are in this temperature range, the current flowing through them is limited when the humidity control device 30 becomes hot, so that excessive heat generation in the humidity control device 30 is efficiently suppressed. Therefore, thermal degradation of the moisture absorbing layer 36 caused by excessive heat generation can be suppressed. The lower limit of the Curie point of the material constituting the outer peripheral wall 32 and the partition wall 35 is preferably 80°C or higher, more preferably 100°C or higher, even more preferably 110°C or higher, and particularly preferably 125°C or higher, from the viewpoint of efficiently heating the moisture absorbing layer 36. The upper limit of the Curie point is preferably 200°C or lower, more preferably 190°C or lower, even more preferably 180°C or lower, and particularly preferably 150°C or lower, from the viewpoint of safety as a part placed in or near the vehicle interior.

[0055] The Curie point of the material forming the outer peripheral wall 32 and the partition walls 35 can be adjusted by the type and amount of the shifter added. For example, the Curie point of barium titanate (BaTiO) is approximately 120°C, but by substituting part of the Ba and Ti with one or more of Sr, Sn, and Zr, the Curie point can be shifted to a lower temperature.

[0056] In this specification, the Curie point is measured by the following method: A sample is attached to a sample holder for measurement and placed in a measurement chamber (e.g., MINI-SUBZERO MC-810P, manufactured by Espec Corporation). The change in the sample's electrical resistance relative to temperature is measured as the temperature rises from 10°C using a DC resistance meter (e.g., Multimeter 3478A, manufactured by Hewlett-Packard Japan, LLC). The Curie point is determined by the temperature at which the resistance value, based on the electrical resistance-temperature plot obtained from the measurement, is twice the resistance value at room temperature (25°C).

[0057] (3-2. Pair of electrodes 37a, 37b) The positions of the pair of electrodes 37a, 37b are not particularly limited, but may be provided on the first end face 33a and the second end face 33b as shown in Fig. 2A. The pair of electrodes 37a, 37b may also be provided on the outer peripheral wall 32 parallel to the extension direction of the cells 34. By applying a voltage between the pair of electrodes 37a and 37b, it becomes possible to cause the honeycomb structure 31 to generate heat by Joule heat.

[0058] The pair of electrodes 37a, 37b is not particularly limited, and may be, for example, a metal or alloy containing at least one selected from Cu, Ag, Al, Ni, and Si. Alternatively, an ohmic electrode capable of making ohmic contact with the outer peripheral wall 32 and / or the partition wall 35 having PTC characteristics may be used. The ohmic electrode may contain, for example, at least one selected from Al, Au, Ag, and In as a base metal and at least one selected from Ni, Si, Zn, Ge, Sn, Se, and Te as a dopant for n-type semiconductors. The pair of electrodes 37a, 37b may have a single-layer structure or a stacked structure of two or more layers. When the pair of electrodes 37a, 37b has a stacked structure of two or more layers, the materials of the layers may be the same or different.

[0059] The thickness of the pair of electrodes 37a, 37b can be set appropriately depending on the method for forming the pair of electrodes 37a, 37b. Examples of methods for forming the pair of electrodes 37a, 37b include metal deposition methods such as sputtering, vapor deposition, electrolytic deposition, and chemical deposition. The pair of electrodes 37a, 37b can also be formed by applying an electrode paste and then baking it, or by thermal spraying. Furthermore, the pair of electrodes 37a, 37b may be formed by joining metal or alloy plates.

[0060] The thickness of the pair of electrodes 37a, 37b is preferably about 5 to 30 μm for baking of electrode paste, about 100 to 1000 nm for dry plating such as sputtering and vapor deposition, about 10 to 100 μm for thermal spraying, and about 5 to 30 μm for wet plating such as electrolytic deposition and chemical deposition. Furthermore, when joining metal or alloy plates, the thickness is preferably about 5 to 100 μm.

[0061] (3-3. Terminal 38) Terminal 38 is connected to the pair of electrodes 37a, 37b and is provided on at least a portion of the pair of electrodes 37a, 37b. Providing terminal 38 facilitates connection to an external power source. Terminal 38 is connected to a conductor that is connected to the external power source.

[0062] The material of the terminal 38 is not particularly limited, but may be, for example, a metal. As the metal, a single metal or an alloy may be used, but from the viewpoints of corrosion resistance, electrical resistivity, and linear expansion coefficient, an alloy containing at least one selected from the group consisting of Cr, Fe, Co, Ni, Cu, Al, and Ti is preferable, and stainless steel, an Fe-Ni alloy, and phosphor bronze are more preferable.

[0063] The size and shape of the terminal 38 are not particularly limited. For example, as shown in Fig. 2A, the terminal 38 may be provided over the entire pair of electrodes 37a, 37b on the outer peripheral wall 32. The terminal 38 may also be provided over a portion of the pair of electrodes 37a, 37b on the outer peripheral wall 32, or may be provided so as to extend outward beyond the outer edges of the pair of electrodes 37a, 37b on the outer peripheral wall 32. The terminal 38 may also be provided over a portion of the pair of electrodes 37a, 37b on the partition wall 35, or may be provided so as to cover some of the cells 34. The thickness of the terminal 38 is not particularly limited, but is, for example, 0.01 to 10 mm, typically 0.05 to 5 mm.

[0064] The method of connecting the terminal 38 and the pair of electrodes 37a, 37b is not particularly limited as long as they are electrically connected, and they can be connected by, for example, diffusion bonding, a mechanical pressure mechanism, welding, or the like.

[0065] (3-4. Moisture absorption layer 36) The moisture absorbing layer 36 is a layer containing a moisture absorbing material, and has the function of absorbing moisture (water vapor). The moisture absorbing layer 36 can be provided on the surface of the partition wall 35 (in the case of the outermost cell 34, the partition wall 35 and the outer wall 32 that define the outermost cell 34). By providing the moisture absorbing layer 36 in this manner, moisture can be easily adsorbed during moisture absorption treatment, and the moisture absorbing layer 36 can be easily heated during regeneration treatment, so that the desired function of the moisture absorbing layer 36 can be regenerated.

[0066] The moisture absorbing material contained in the moisture absorbing layer 36 preferably has the function of absorbing moisture at temperatures between -20 and 40°C and releasing moisture at temperatures as high as 60°C or higher. The moisture absorbent is not particularly limited, but examples thereof include aluminosilicate, silica gel, silica, graphene oxide, polymer adsorbent, polystyrene sulfonic acid, and metal organic framework (MOF). These may be used alone or in combination of two or more.

[0067] The aluminosilicate is preferably a porous clay mineral such as AFI-type, CHA-type or BEA-type zeolite, allophane, imogolite, etc. The aluminosilicate is preferably amorphous.

[0068] As the silica gel, it is preferable to use type A silica gel. The polymer adsorbent is preferably one having a polyacrylic acid polymer chain, such as sodium polyacrylate. A metal-organic framework is a crystalline hybrid material containing metal ions and organic molecules (organic ligands). The metal ions are preferably hydrophilic metal ions (e.g., aluminum ions).

[0069] The moisture absorption layer 36 is preferably capable of adsorbing carbon dioxide and / or volatile components in addition to moisture. Specifically, the moisture absorption layer 36 can further contain an adsorbent capable of adsorbing carbon dioxide and / or volatile components in addition to a moisture absorbent capable of adsorbing moisture. Furthermore, if the moisture absorbent capable of adsorbing moisture can also adsorb carbon dioxide and / or volatile components, by containing only the moisture absorbent, it is possible to adsorb carbon dioxide and / or volatile components in addition to moisture. By containing such an adsorbent or using such a moisture absorbent, it is possible to obtain an air purification effect in addition to an air dehumidification effect. The adsorbent preferably has a function of being able to adsorb carbon dioxide and / or volatile components at temperatures between -20 and 40°C and desorb them at high temperatures of 60°C or higher. Examples of adsorbents having such functions include zeolite, silica gel, activated carbon, alumina, silica, low-crystalline clay, and amorphous aluminum silicate complexes. The type of adsorbent may be appropriately selected depending on the type of component to be removed. One type of adsorbent may be used alone, or two or more types may be used in combination.

[0070] Volatile components contained in the air inside a vehicle cabin include, for example, volatile organic compounds (VOCs) and odor components other than VOCs. Specific examples of volatile components include ammonia, acetic acid, isovaleric acid, nonenal, formaldehyde, toluene, xylene, paradichlorobenzene, ethylbenzene, styrene, chlorpyrifos, di-n-butyl phthalate, tetradecane, di-2-ethylhexyl phthalate, diazinon, acetaldehyde, and N-methylcarbamate-2-(1-methylpropyl)phenyl.

[0071] The moisture absorption layer 36 may contain a catalyst. By containing a catalyst, oxidation-reduction reactions and the like can be promoted, thereby purifying carbon dioxide and / or volatile components. Examples of catalysts having such functions include metal catalysts such as Pt, Pd, and Ag, and oxide catalysts such as CeO2 and ZrO2. One type of catalyst may be used alone, or two or more types may be used in combination. Furthermore, the catalyst may be used in combination with the above-mentioned functional materials.

[0072] The thickness of the moisture absorbing layer 36 is not particularly limited and may be determined depending on the size of the cells 34. For example, from the viewpoint of ensuring sufficient contact with air, the thickness of the moisture absorbing layer 36 is preferably 20 μm or more, more preferably 25 μm or more, and even more preferably 30 μm or more. On the other hand, from the viewpoint of preventing the moisture absorbing layer 36 from peeling off from the partition walls 35 and the outer peripheral wall 32, the thickness of the moisture absorbing layer 36 is preferably 400 μm or less, more preferably 380 μm or less, and even more preferably 350 μm or less.

[0073] The thickness of the moisture absorption layer 36 is measured by the following procedure. An arbitrary cross section parallel to the flow path direction of the honeycomb structure 31 is cut out, and a cross-sectional image at approximately 50x magnification is obtained using a scanning electron microscope or the like. This cross section is also set to pass through the center of gravity of the cross section perpendicular to the flow path direction of the honeycomb structure 31. For each moisture absorption layer 36 visible in the cross-sectional image, the thickness is calculated by dividing the cross-sectional area by the length of the cell 34 in the flow path direction. This calculation is performed for all moisture absorption layers 36 visible in the cross-sectional image, and the overall average value is taken as the thickness of the moisture absorption layer 36.

[0074] From the viewpoint of exhibiting the desired function in the humidity control device 30, the amount of the moisture absorption layer 36 is preferably 50 to 500 g / L, more preferably 100 to 400 g / L, and even more preferably 150 to 350 g / L relative to the volume of the honeycomb structure 31. The volume of the honeycomb structure 31 is a value determined by the outer dimensions of the honeycomb structure 31.

[0075] (3-5. Manufacturing Method of Humidity Control Device 30) The method for producing the humidity control device 30 is not particularly limited and can be carried out in accordance with a known method. Hereinafter, an example of a method for producing the humidity control device 30 will be described. The method for manufacturing the honeycomb structure 31 that constitutes the humidity control device 30 includes a molding step and a firing step. In the molding step, a clay containing ceramic raw materials including BaCO3 powder, TiO2 powder, and powder of a rare earth nitrate or hydroxide is molded to produce a honeycomb molded body with a relative density of 60% or more. The ceramic raw material can be obtained by dry mixing each powder to obtain a desired composition. The clay can be obtained by adding a dispersion medium, a binder, a plasticizer, and a dispersant to a ceramic raw material and kneading the mixture. The clay may contain additives such as a sifter, a metal oxide, a property improver, and a conductive powder, as needed. The blending amount of components other than the ceramic raw materials is not particularly limited as long as it is an amount that allows the relative density of the honeycomb formed body to be 60% or more.

[0076] Here, in this specification, the "relative density of the honeycomb formed body" means the ratio of the density of the honeycomb formed body to the true density of the entire ceramic raw material. Specifically, it can be calculated by the following formula. Relative density (%) of honeycomb formed body = Density of honeycomb formed body (g / cm 3 ) / true density of the entire ceramic raw material (g / cm 3 ) x 100 The density of the honeycomb formed body can be measured by the Archimedes method using pure water as a medium. The true density of the entire ceramic raw material is calculated by multiplying the total mass (g) of each raw material by the total volume (cm) of each raw material. 3 ) can be calculated by dividing by

[0077] Examples of the dispersion medium include water and a mixed solvent of water and an organic solvent such as alcohol, with water being particularly preferred.

[0078] Examples of binders include organic binders such as methyl cellulose, hydroxypropoxyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, and polyvinyl alcohol. It is particularly preferable to use a combination of methyl cellulose and hydroxypropoxyl cellulose. While one binder may be used alone or two or more binders may be used in combination, it is preferable that the binder does not contain an alkali metal element.

[0079] Examples of the plasticizer include polyoxyalkylene alkyl ether, polycarboxylic acid polymer, and alkyl phosphate ester.

[0080] The dispersant may be a surfactant such as polyoxyalkylene alkyl ether, ethylene glycol, dextrin, fatty acid soap, polyalcohol, etc. The dispersant may be used alone or in combination of two or more.

[0081] The honeycomb formed body can be produced by extrusion molding of a clay. In extrusion molding, a die having a desired overall shape, cell shape, partition wall thickness, cell density, etc. can be used.

[0082] The relative density of the honeycomb formed body obtained by extrusion molding is 60% or more, preferably 65% ​​or more. By controlling the relative density of the honeycomb formed body within this range, it is possible to densify the honeycomb formed body and reduce its electrical resistance at room temperature. The upper limit of the relative density of the honeycomb formed body is not particularly limited, but is generally 80%, preferably 75%.

[0083] The honeycomb molded body can be dried before the firing step. The drying method is not particularly limited, and for example, a conventionally known drying method such as hot air drying, microwave drying, dielectric drying, reduced pressure drying, vacuum drying, freeze drying, etc. Among these, a drying method that combines hot air drying with microwave drying or dielectric drying is preferred because it can dry the entire molded body quickly and uniformly.

[0084] The firing step involves holding the temperature at 1150 to 1250°C, then raising the temperature to a maximum temperature of 1360 to 1430°C at a rate of 20 to 600°C / hour, and holding the temperature for 0.5 to 10 hours. By holding the honeycomb formed body at a maximum temperature of 1360 to 1430°C for 0.5 to 10 hours, a honeycomb structure 31 containing, as a main component, BaTiO3-based crystal particles in which part of Ba has been substituted with a rare earth element can be obtained. Furthermore, by maintaining the temperature at 1150 to 1250°C, Ba2TiO4 crystal particles generated during the firing process can be easily removed, and the honeycomb structure 31 can be made dense. Furthermore, by setting the heating rate from 1150 to 1250°C to the maximum temperature of 1360 to 1430°C at 20 to 600°C / hour, 1.0 to 10.0 mass% of Ba6Ti 17 O 40 Crystal grains can be generated in the honeycomb structure 31 .

[0085] The holding time at 1150 to 1250°C is not particularly limited, but is preferably 0.5 to 10 hours. By holding for such a time, Ba2TiO4 crystal particles formed during the firing process can be stably and easily removed.

[0086] The firing step preferably includes holding the mixture at 900 to 950°C for 0.5 to 5 hours during heating. Holding the mixture at 900 to 950°C for 0.5 to 5 hours allows BaCO3 to efficiently decompose, making it easier to obtain a honeycomb structure 31 having a predetermined composition.

[0087] Before the firing step, a degreasing step may be carried out to remove the binder. The degreasing step is preferably carried out in an air atmosphere to completely decompose the organic components. Furthermore, the firing step is preferably carried out in an air atmosphere from the viewpoint of controlling electrical properties and reducing manufacturing costs. The firing furnace used in the firing step and degreasing step is not particularly limited, but an electric furnace, a gas furnace, or the like can be used.

[0088] A pair of electrodes 37a, 37b are formed on the honeycomb structure 31 obtained in this manner. The pair of electrodes 37a, 37b can be formed by a metal deposition method such as sputtering, vapor deposition, electrolytic deposition, or chemical deposition. The pair of electrodes 37a, 37b can also be formed by applying an electrode paste and then baking it. Furthermore, the pair of electrodes 37a, 37b can also be formed by thermal spraying. The pair of electrodes 37a, 37b may be formed of a single layer, or may be formed of multiple electrode layers with different compositions. Representative methods for forming the pair of electrodes 37a, 37b will be described below.

[0089] First, an electrode slurry containing an electrode material, an organic binder, and a dispersion medium is prepared and applied to the first end face 33a or the second end face 33b of the honeycomb structure 31. The dispersion medium can be water, an organic solvent (e.g., toluene, xylene, ethanol, n-butanol, ethyl acetate, butyl acetate, terpineol, dihydroterpineol, texanol, ethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether acetate, diethylene glycol monobutyl ether), or a mixture thereof. Excess slurry on the outer periphery of the honeycomb structure 31 is removed by blowing and wiping. Thereafter, the slurry is dried to form a pair of electrodes 37a, 37b on the first end face 33a or the second end face 33b of the honeycomb structure 31. Drying can be performed while heating the honeycomb structure 31 to a temperature of, for example, about 120 to 600°C. The series of steps of coating, slurry removal, and drying may be carried out only once, but by repeating these steps multiple times, a pair of electrodes 37a, 37b of a desired thickness can be provided.

[0090] Next, terminals 38 are placed at predetermined positions of the pair of electrodes 37a, 37b, and the pair of electrodes 37a, 37b are connected to the terminals 38. The method for connecting the pair of electrodes 37a, 37b to the terminals 38 can be the method described above. The terminal 38 may be installed after the moisture absorbing layer 36 described below is formed.

[0091] Next, a moisture absorbing layer 36 is formed on the surfaces of the partition walls 35 and the like of the honeycomb structure 31 . The method for forming the moisture absorption layer 36 is not particularly limited, and it can be formed, for example, by the following process. The honeycomb structure 31 is immersed in a slurry containing a moisture absorbent, an organic binder, and a dispersion medium for a predetermined period of time, and excess slurry on the end faces and outer periphery of the honeycomb structure 31 is removed by blowing and wiping. The dispersion medium can be water, an organic solvent (e.g., toluene, xylene, ethanol, n-butanol, ethyl acetate, butyl acetate, terpineol, dihydroterpineol, Texanol, ethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether acetate, diethylene glycol monobutyl ether), or a mixture thereof. Thereafter, the slurry is dried to form the moisture absorption layer 36 on the surface of the partition wall 35. The drying can be performed while heating the honeycomb structure 31 to a temperature of, for example, about 120 to 600°C. The series of steps of immersion, slurry removal, and drying may be carried out only once, but by repeating the steps multiple times, a moisture absorbing layer 36 of a desired thickness can be provided on the surface of the partition wall 35 or the like.

[0092] (4. Control unit 40) The control unit 40 is electrically connected to the ventilator 20, the humidity control device 30, and each valve (first valve 51, second valve 52, and third valve 53). A power source (not shown) may be disposed between each component and the control unit 40. The power source is not particularly limited, and a battery or the like can be used. The control unit 40 controls the power supply to control the state of voltage application to the pair of electrodes 37a, 37b of the humidity control device 30, and can adjust the heating state of the honeycomb structure 31. The control unit 40 also controls each valve to control the flow of air. Furthermore, the control unit 40 can control the flow rate of air circulating in the air conditioning duct 10 by adjusting the rotation speed of the fan 20.

[0093] The control unit 40 is not particularly limited, but is generally an ECU (Engine (electronic) Control Unit). The ECU includes a CPU that executes various arithmetic processes, a ROM that stores programs and data required for the control, a RAM that temporarily stores the results of the CPU calculations, and an input / output port for inputting and outputting signals to and from the outside.

[0094] The control unit 40 can execute a dehumidification (moisture absorption) mode, a regeneration mode, and a fan mode. These modes will be described below. (Dehumidification mode) In the dehumidification mode, the control unit 40 controls the first valve 51 and the third valve 53 so that air sequentially flows into the first flow path 11, the third flow path 13, and the fifth flow path 15. Specifically, the control unit 40 opens the first valve 51 and switches the third valve 53 so that air flows into the third flow path 13 but does not flow into the fourth flow path 14. By controlling in this manner, the air that flows into the first flow path 11 is dehumidified in the humidity control device 30 and can be returned to the vehicle cabin via the third flow path 13 and the fifth flow path 15. In this dehumidification mode, the control unit 40 may control the second valve 52 so that a portion of the air flows into the second flow path 12. By controlling in this manner, excessive dehumidification can be suppressed, and the humidity of the air in the vehicle cabin can be optimized.

[0095] (Playback mode) In the regeneration mode, the control unit 40 controls the first valve 51 and the third valve 53 so that air sequentially flows into the first flow path 11 and the fourth flow path 14. Specifically, the first valve 51 is opened, and the third valve 53 is switched so that air does not flow into the third flow path 13 but flows into the fourth flow path 14. The control unit 40 also applies a voltage to the humidity control device 30 to heat it. By controlling in this manner, the moisture trapped in the moisture absorption layer 36 is released, and the moisture-containing air is discharged outside the vehicle via the fourth flow path 14. In this regeneration mode, the control unit 40 may control the second valve 52 so that a portion of the air flows into the second flow path 12. By controlling in this manner, air is constantly circulating in the vehicle air conditioning system, so that cooling or heating can be continuously performed by an evaporator or the like provided downstream of the fifth flow path 15.

[0096] In the regeneration mode, it is preferable to heat the moisture absorption layer 36 to a temperature equal to or higher than the desorption temperature depending on the type of moisture absorbent material in order to promote desorption of moisture trapped in the moisture absorption layer 36. For example, it is preferable to heat the moisture absorption layer 36 to 70 to 150°C, more preferably to 80 to 140°C, and even more preferably to 90 to 130°C.

[0097] (Blowing mode) The air blowing mode is performed when dehumidification or regeneration of the humidity control device 30 is not required. In the air blowing mode, the control unit 40 controls the second valve 52 so that air sequentially flows into the second flow path 12 and the fifth flow path 15. Specifically, the first valve 51 is closed and the second valve 52 is opened. By performing this control, the air that flows into the second flow path 12 can be returned to the passenger compartment via the fifth flow path 15. At this time, cooling or heating may be performed by an evaporator or the like provided downstream of the fifth flow path 15. Therefore, when dehumidification or regeneration of the humidity control device 30 is not performed, the load on the ventilator 20 can be reduced, thereby saving power.

[0098] <Embodiment 2> FIG. 3 is a schematic diagram showing the overall configuration of a vehicle air conditioning system according to a second embodiment of the present invention. 3, the vehicle air conditioning system according to the second embodiment of the present invention differs from the vehicle air conditioning system according to the first embodiment of the present invention in that it does not include the first valve 51. That is, the vehicle air conditioning system according to the second embodiment of the present invention is basically the same as the vehicle air conditioning system according to the first embodiment of the present invention, except that it does not include the first valve 51. Note that components having the same reference numerals as those appearing in the description of the vehicle air conditioning system according to embodiment 1 of the present invention are the same as the components of the vehicle air conditioning system according to embodiment 2 of the present invention.

[0099] The vehicle air conditioning system according to the second embodiment of the present invention does not have the first valve 51, and therefore cannot cause air to flow only into the second flow path 12. However, by increasing the opening of the second valve 52, air can be preferentially caused to flow into the second flow path 12. Furthermore, the vehicle air conditioning system according to the second embodiment of the present invention can be simplified by omitting the first valve 51. Furthermore, the vehicle air conditioning system according to the second embodiment of the present invention can also achieve the same effects as the vehicle air conditioning system according to the first embodiment of the present invention.

[0100] The minimum cross-sectional area of ​​the second flow path 12 is preferably larger than the minimum cross-sectional area of ​​the first flow path 11. By controlling the minimum cross-sectional area in this manner, when dehumidification or regeneration of the humidity control device 30 is not required, it becomes easier to cause air to preferentially flow into the second flow path 12, which has a smaller pressure loss than the first flow path 11 in which the humidity control device 30 is arranged. Here, the "minimum cross-sectional area" of each flow path means the area of ​​the cross section perpendicular to the air flow direction at the narrowest part of each flow path.

[0101] The minimum cross-sectional area of ​​the fourth flow path 14 is preferably smaller than the minimum cross-sectional area of ​​the third flow path 13. Specifically, the minimum cross-sectional area of ​​the third flow path 13 is preferably four times or more the minimum cross-sectional area of ​​the fourth flow path 14. By controlling the minimum cross-sectional area in this manner, the flow rate of air that flows into the first flow path 11 and then into the third flow path 13 during dehumidification can be increased, thereby enabling the adsorption process by the humidity control device 30 to be carried out efficiently. Furthermore, the flow rate of air that flows into the first flow path 11 and then into the fourth flow path 14 can be reduced during regeneration of the humidity control device 30, allowing the regeneration process of the humidity control device 30 to be carried out efficiently. The upper limit of the minimum cross-sectional area of ​​the third flow path 13 is not particularly limited, but is preferably 15 times or less the minimum cross-sectional area of ​​the fourth flow path 14 from the viewpoint of miniaturizing the vehicle air conditioning system.

[0102] The minimum cross-sectional area of ​​the second flow path 12 is preferably at least twice the minimum cross-sectional area of ​​the third flow path 13. By controlling the minimum cross-sectional area in this manner, it becomes easier to cause air to preferentially flow into the second flow path 12, which has a smaller pressure loss than the third flow path 13, when dehumidification or regeneration of the humidity control device 30 is not required. The upper limit of the minimum cross-sectional area of ​​the second flow path 12 is not particularly limited, but is preferably six times or less the minimum cross-sectional area of ​​the third flow path 13 from the viewpoint of miniaturizing the vehicle air conditioning system.

[0103] In the vehicle air conditioning system according to the second embodiment of the present invention, the control unit 40 is electrically connected to the ventilator 20, the humidity control device 30, and each valve (the second valve 52 and the third valve 53). The control unit 40 can execute a dehumidification (moisture absorption) mode, a regeneration mode, and a fan mode. These modes will be described below.

[0104] (Dehumidification mode) In the dehumidification mode, the control unit 40 controls the third valve 53 so that air sequentially flows into the first flow path 11, the third flow path 13, and the fifth flow path 15. Specifically, the third valve 53 is switched so that air flows into the third flow path 13 and air does not flow into the fourth flow path 14. By controlling in this manner, the air that flows into the first flow path 11 is dehumidified in the humidity control device 30 and can be returned to the vehicle cabin via the third flow path 13 and the fifth flow path 15. In this dehumidification mode, the control unit 40 may control the second valve 52 so that a portion of the air flows into the second flow path 12. By controlling in this manner, excessive dehumidification can be suppressed, and the humidity of the air in the vehicle cabin can be optimized.

[0105] (Playback mode) In the regeneration mode, the control unit 40 controls the third valve 53 so that air sequentially flows into the first flow path 11 and the fourth flow path 14. Specifically, the control unit 40 switches the third valve 53 so that air does not flow into the third flow path 13 and air flows into the fourth flow path 14. The control unit 40 also applies a voltage to the humidity control device 30 to heat it. By controlling in this manner, the moisture trapped in the moisture absorption layer 36 is released, and the moisture-containing air is discharged outside the vehicle via the fourth flow path 14. In this regeneration mode, the control unit 40 may control the second valve 52 so that a portion of the air flows into the second flow path 12. By controlling in this manner, air is constantly circulating in the vehicle air conditioning system, so that cooling or heating can be continuously performed by an evaporator or the like provided downstream of the fifth flow path 15.

[0106] (Blowing mode) The air blowing mode is performed when dehumidification or regeneration of the humidity control device 30 is not required. In the air blowing mode, the control unit 40 controls the second valve 52 so that air sequentially flows into the second flow path 12 and the fifth flow path 15. Specifically, the control unit 40 controls the second valve 52 to open. By performing this control, the air that flows into the second flow path 12 can be returned to the vehicle cabin via the fifth flow path 15. At this time, cooling or heating may be performed by an evaporator or the like provided downstream of the fifth flow path 15. Therefore, when dehumidification or regeneration of the humidity control device 30 is not performed, the load on the fan 20 can be reduced, thereby achieving power saving.

[0107] The features of the vehicle air conditioning system according to the second embodiment of the present invention can be combined with the vehicle air conditioning system according to the second embodiment of the present invention within the scope that does not impair the effects of the present invention. For example, the feature of the minimum cross-sectional area of ​​each flow path may be applied to the vehicle air conditioning system according to the first embodiment of the present invention. [Explanation of symbols]

[0108] 10 Air conditioning duct 11 First flow path 12 Second flow path 13 Third Channel 14 Fourth Channel 15 5th Channel 20 Ventilator 30 Humidity Control Device 31 Honeycomb structure 32 Outer wall 33a 1st end surface 33b 2nd end face 34 cells 35 Bulkhead 36 Moisture absorption layer 37a,37b electrode 38 terminals 40 Control Unit 51 First valve 52 Second valve 53 Third valve

Claims

1. an air conditioning duct through which air from the vehicle compartment or outside the vehicle can circulate; a fan disposed in the air conditioning duct; a honeycomb structure having an outer peripheral wall, and partition walls disposed inside the outer peripheral wall and defining a plurality of cells that serve as the air flow path extending from a first end face to a second end face; and a humidity control device having a moisture absorption layer provided on a surface of the partition wall, the humidity control device being disposed in the air conditioning duct downstream of the fan; A vehicle air conditioning system comprising: the air conditioning duct is branched downstream of the fan into a first flow path in which the humidity control device is disposed and a second flow path in which the humidity control device is not disposed, the first flow path further branches into a third flow path that causes the air to flow into the vehicle compartment and a fourth flow path that causes the air to flow out of the vehicle, a second valve capable of adjusting the amount of air that flows in is disposed in the second flow path; a third valve capable of switching the flow of the air between the third flow path and the fourth flow path is disposed at a branch point between the third flow path and the fourth flow path.

2. The vehicle air conditioning system according to claim 1 , wherein a first valve capable of adjusting the amount of air that flows in is disposed in the first flow path upstream of the humidity control device.

3. The vehicle air conditioning system according to claim 2 , further comprising a control unit capable of controlling the first valve, the second valve, and the third valve.

4. The vehicle air conditioning system according to claim 3 , wherein the control unit controls the opening degrees of the first valve and the second valve when the humidity control device is in a moisture absorption mode or a regeneration mode.

5. The flow rate of the air generated by the fan is 3 m 3 5. The vehicle air conditioning system according to claim 4, wherein the control unit controls the ratio of the opening degree of the second valve to the opening degree of the first valve to be 0.5 or less when the air temperature is below 0.5 / minute.

6. The flow rate of the air generated by the fan is 3 m 3 5. The vehicle air conditioning system according to claim 4, wherein when the ratio of the opening degree of the second valve to the opening degree of the first valve exceeds 0.3 / minute, the control unit controls the ratio of the opening degree of the second valve to the opening degree of the first valve to 0.3 or more.

7. 7. The vehicle air conditioning system according to claim 1, wherein a minimum cross-sectional area of ​​the second flow path is larger than a minimum cross-sectional area of ​​the first flow path, and a minimum cross-sectional area of ​​the fourth flow path is smaller than a minimum cross-sectional area of ​​the third flow path.

8. 8. The vehicle air conditioning system according to claim 7, wherein the minimum cross-sectional area of ​​the second flow path is at least twice as large as the minimum cross-sectional area of ​​the third flow path.

9. 8. The vehicle air conditioning system according to claim 7, wherein the minimum cross-sectional area of ​​the third flow path is at least four times the minimum cross-sectional area of ​​the fourth flow path.

10. 7. The vehicle air conditioning system according to claim 1, wherein at least the partition walls of the honeycomb structure are made of a material having PTC properties.

11. The vehicle air conditioning system according to any one of claims 1 to 6, wherein the humidity control device further comprises a pair of electrodes provided on the first end face and the second end face of the honeycomb structure, or on the outer wall parallel to the direction in which the cells of the honeycomb structure extend.

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