Vehicular air conditioning system

Abstract

To provide a vehicular air conditioning system configured to prevent water droplets from adhering to the inside of an air conditioning duct during a regeneration process.SOLUTION: A vehicular air conditioning system is provided with: an air conditioning duct 10 through which air can flow; a first moisture conditioning unit 20 which is arranged in the air conditioning duct 10 and which has a honeycomb structure 22 which has an outer peripheral wall 23 and a bulkhead 26 which is arranged inside the outer peripheral wall 23 and sections and forms a plurality of cells 25 that constitute a flow path extending from a first end face 24a to a second end face 24b, where at least the bulkhead 26 is composed of materials having PTC characteristics, and one or more moisture conditioning devices 21 which include a pair of electrodes 27a and 27b provided on the honeycomb structure 22 and a moisture absorbing material-containing layer 28 formed on a surface of the bulkhead 26; a second moisture conditioning unit 30 which has one or more moisture conditioning members 31 including moisture absorbing materials and is arranged in the air conditioning duct 10 arranged closer to a downstream side than the first moisture conditioning unit 20; and a power source 40 for applying voltages to the moisture conditioning device 21. Total amounts of the moisture absorbing materials in the second moisture conditioning unit 30 are equal to 0.3-12 times of total amounts of the moisture absorbing materials in the first moisture conditioning unit 20.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] There is an increasing demand for improved cabin environments in automobiles and other vehicles. A specific example of such a demand is the ability to control humidity inside the cabin. Ventilation is an effective measure to meet such demands, but ventilation can cause a large loss of heater energy in winter, leading to reduced energy efficiency in winter. In particular, electric vehicles (BEVs: Battery Electric Vehicles) have the problem that the energy loss significantly reduces their driving range.

[0003] As a method for solving the above problem, Patent Document 1 discloses a vehicle air conditioning system that includes a moisture absorbing device that absorbs water vapor contained in the air in the vehicle cabin and releases the water vapor absorbed by the moisture absorbing device by heating. The moisture absorbing device includes a moisture absorbing section that absorbs water vapor in the air and a plurality of heating sections that directly heat the upstream and downstream regions of the moisture absorbing section separately during regeneration. The moisture absorbing section is a sheet that is folded into a pleated shape and has breathability and carries a predetermined moisture absorbent, and the base material may be honeycomb-shaped or mesh-shaped. The heating section is a plate-shaped heater that extends in a direction along the air flow and is in contact with the sheet in the upstream and downstream regions of the moisture absorbing section. This configuration makes it possible to regenerate the entire moisture absorbing section more uniformly.

[0004] On the other hand, Patent Document 2 discloses a heater element having a columnar honeycomb structure having an outer peripheral wall and partition walls disposed inside the outer peripheral wall and partitioning a plurality of cells that form a flow path from a first end face to a second end face, the partition walls having a PTC characteristic, an average thickness of the partition walls being 0.13 mm or less, and an opening ratio at the first end face and the second end face being 0.81 or more. This heater element is used for heating the vehicle interior, and since the heating area can be increased by having a honeycomb structure, it is an efficient heating means. Therefore, it is considered that using such a heater element as a carrier for a moisture absorbent can contribute to shortening the regeneration time of the moisture absorbent. In particular, since this heater element can be heated by current and has a PTC characteristic, it is considered that it can easily heat the moisture absorbent while suppressing excessive heat generation and suppressing thermal deterioration of the moisture absorbent. In addition, since the risk of excessive temperature is avoided, safety can be ensured even if the initial resistance is set small and the heating rate is increased, and the temperature can be raised in a short time. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2022-80532 A [Patent Document 2] International Publication No. 2020 / 036067 Summary of the Invention [Problem to be solved by the invention]

[0006] In the vehicle air conditioning system of Patent Document 1, when performing a regeneration process in which the water vapor adsorbed in the moisture adsorption device is desorbed by heating, high humidity air flows all at once downstream of the moisture adsorption device, so the water vapor tends to condense and become water droplets downstream of the moisture adsorption device. As a result, the water droplets tend to adhere and remain in the air conditioning duct, making it difficult to discharge them outside the vehicle. If the regeneration process is terminated and the moisture adsorption process is performed in this state, there is a risk that the water droplets will enter the vehicle cabin.

[0007] The present invention has been made to solve the above-mentioned problems, and has an object to provide a vehicle air conditioning system in which water droplets are less likely to adhere to the inside of the air conditioning duct during regeneration processing. [Means for solving the problem]

[0008] As a result of intensive research into vehicle air conditioning systems, the inventors have found that the above-mentioned problems can be solved by providing a first humidity control unit and a second humidity control unit in an air conditioning duct and controlling the ratio of the total amount of moisture absorbent in these humidity control units within an appropriate range, and have completed the present invention. That is, the present invention is exemplified as follows.

[0009] (1) an air conditioning duct through which air can flow; a honeycomb structure having an outer peripheral wall and partition walls disposed inside the outer peripheral wall and defining a plurality of cells that become flow paths extending from a first end face to a second end face, the partition walls being made of a material having a PTC characteristic; and a first humidity control unit disposed in the air conditioning duct, the first humidity control unit having one or more humidity control devices including a pair of electrodes provided on the honeycomb structure and a moisture absorbent-containing layer formed on a surface of the partition walls; A second humidity control unit having one or more humidity control members including a moisture absorbent and disposed in the air conditioning duct downstream of the first humidity control unit; a power source for applying a voltage to the humidity control device; Equipped with A vehicle air conditioning system, wherein a total amount of the moisture absorbent in the second humidity control unit is 0.3 to 12 times a total amount of the moisture absorbent in the first humidity control unit.

[0010] (2) The vehicle air conditioning system described in (1), wherein the humidity control member includes a honeycomb structure having an outer peripheral wall and partition walls arranged inside the outer peripheral wall and defining a plurality of cells that serve as flow paths extending from a first end face to a second end face, and a moisture-absorbent material-containing layer formed on a surface of the partition wall.

[0011] (3) The humidity control member has a partition wall thickness of 0.06 to 0.40 mm and a cell density of 30 to 95 cells / cm. 2 The vehicle air conditioning system according to (2).

[0012] (4) The vehicle air conditioning system according to any one of (1) to (3), wherein the humidity control member does not have a heater function.

[0013] (5) The vehicle air conditioning system according to any one of (1) to (4), wherein a total amount of the moisture absorbent in the second humidity control unit is 0.5 to 8 times a total amount of the moisture absorbent in the first humidity control unit.

[0014] (6) The vehicle air conditioning system according to any one of (1) to (5), wherein a total amount of the moisture absorbent in the second humidity control unit is 0.6 to 6 times a total amount of the moisture absorbent in the first humidity control unit.

[0015] (7) The vehicle air conditioning system according to any one of (1) to (6), wherein the humidity control device is provided with the pair of electrodes on the first end surface and the second end surface.

[0016] (8) The vehicle air conditioning system according to any one of (1) to (7), wherein the distance between the first humidity control unit and the second humidity control unit is 10 cm or less.

[0017] (9) The air conditioning duct has, downstream of the second humidity control unit, a first passage for introducing the air into a vehicle compartment and a second passage for discharging the air to the outside of the vehicle, The vehicle air conditioning system according to any one of (1) to (8), further comprising a switching valve capable of switching the flow of the air between the first path and the second path.

[0018] (10) a dehumidification mode in which the switching valve is controlled to switch the flow of the air to the first path to dehumidify the vehicle interior; a regeneration mode in which a voltage is applied from the power source to the pair of electrodes of the humidity control device and the switching valve is controlled to switch the flow of the air to the second path, thereby regenerating the moisture absorbent; The vehicle air conditioning system according to (9), further comprising a control unit capable of executing the above.

[0019] (11) The vehicle air conditioning system according to any one of (1) to (10), wherein the material having a PTC characteristic is mainly composed of barium titanate.

[0020] (12) The vehicle air conditioning system according to any one of (1) to (11), wherein the moisture-absorbing material-containing layer of the humidity control device further contains a functional material having a function of adsorbing at least one selected from carbon dioxide and a volatile component, and / or a catalyst. Effect of the Invention

[0021] According to the present invention, it is possible to provide a vehicle air conditioning system in which water droplets are less likely to adhere to the inside of the air conditioning duct during regeneration processing. [Brief description of the drawings]

[0022] [Figure 1] 1 is a schematic diagram illustrating an overall configuration of a vehicle air conditioning system according to an embodiment of the present invention; [Figure 2A] 1 is a schematic diagram of a cross section parallel to a flow path direction of a humidity control device used in a vehicle air conditioning system according to an 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 a-a'. [Diagram 3] 13 is a graph showing the relationship between the regeneration process time and the relative humidity in the air conditioning duct with and without the second humidity control unit. [Figure 4] 1 is a schematic diagram of a cross section parallel to a flow path direction of a humidity control member used in a vehicle air conditioning system according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] The vehicle air conditioning system of the present invention comprises: an air conditioning duct through which air can flow; a honeycomb structure having an outer peripheral wall and partition walls arranged inside the outer peripheral wall and partitioning a plurality of cells that serve as flow paths extending from a first end face to a second end face, with at least the partition walls being made of a material having PTC (Positive Temperature Coefficient) characteristics; a first humidity control unit disposed in the air conditioning duct, the first humidity control unit having one or more humidity control devices including a pair of electrodes provided on the honeycomb structure and a moisture absorbent-containing layer formed on a surface of the partition wall; a second humidity control unit disposed in the air conditioning duct downstream of the first humidity control unit, the second humidity control unit having one or more humidity control members containing a moisture absorbent; and a power source for applying a voltage to the humidity control device; and the total amount of the moisture absorbent in the second humidity control unit is 0.3 to 12 times the total amount of the moisture absorbent in the first humidity control unit. With this configuration, the vehicle air conditioning system of the present invention can temporarily adsorb some of the moisture in the high-humidity air generated by heating the first humidity control unit during the regeneration process in the downstream second humidity control unit and gradually discharge it. That is, during the regeneration process, the high-humidity air does not flow all at once downstream of the second humidity control unit, so that it is possible to prevent water droplets from adhering to the air conditioning duct and becoming less likely to remain. The vehicle air conditioning system of the present invention also has good humidity control performance.

[0024] Hereinafter, the 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 to the following embodiments, which are made based on the ordinary knowledge of a person skilled in the art, fall within the scope of the present invention, without departing from the spirit of the present invention.

[0025] The vehicle air conditioning system according to the embodiment of the present invention can be suitably used in various vehicles such as automobiles. Examples of the vehicle include, but are not limited to, automobiles and trains. Examples of the vehicle include, but are not limited to, gasoline vehicles, diesel 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 embodiment of the present invention can be suitably used in vehicles that do not have an internal combustion engine, such as electric vehicles and trains.

[0026] Fig. 1 is a schematic diagram of an overall configuration of a vehicle air conditioning system according to an embodiment 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 an embodiment 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.

[0027] 1, a vehicle air conditioning system 100 according to an embodiment of the present invention includes an air conditioning duct 10, a first humidity control unit 20, a second humidity control unit 30, and a power source 40. The vehicle air conditioning system 100 may further include a switching valve 50 and a control unit 60. Air from the vehicle compartment or outside the vehicle can flow through the air conditioning duct 10. The air conditioning duct 10 can have, downstream of the second humidity control unit 30, a first path 10a that introduces air into the vehicle compartment and a second path 10b that exhausts air to the outside of the vehicle. The first humidity control unit 20 has one or more humidity control devices 21, and is disposed inside the air conditioning duct 10. Note that Fig. 1 illustrates an example in which there is one humidity control device 21. The second humidity control unit 30 has one or more humidity control members 31, and is disposed in the air conditioning duct 10 downstream of the first humidity control unit 20. Note that Fig. 1 illustrates an example in which there is one humidity control member 31. The power source 40 can apply a voltage to the humidity control device 21 of the first humidity control unit 20. The switching valve 50 can switch the flow of air between the first path 10a and the second path 10b. The control unit 60 is connected to the power source 40, the switching valve 50, etc., and is capable of controlling these.

[0028] 2A and 2B, the humidity control device 21 includes a honeycomb structure 22 having an outer peripheral wall 23 and partition walls 26 disposed inside the outer peripheral wall 23 and defining a plurality of cells 25 that serve as flow paths extending from a first end face 24a to a second end face 24b, at least the partition walls 26 being made of a material having PTC properties, a pair of electrodes 27a, 27b provided on the honeycomb structure 22, and a moisture absorbent-containing layer 28 formed on the surface of the partition walls 26. The humidity control device 21 may further include terminals 29 connected to the pair of electrodes 27a, 27b.

[0029] In the vehicle air conditioning system 100 having the above-mentioned configuration, air from the vehicle compartment or outside the vehicle flows into the first humidity control unit 20 through the air conditioning duct 10, and moisture in the air is captured (removed) by the moisture absorbent-containing layer 28 of the humidity control device 21 in the first humidity control unit 20. Furthermore, moisture in the air is secondarily captured (removed) by the humidity control member 31 in the second humidity control unit 30. Then, the air with reduced moisture flows into the vehicle compartment through the first path 10a. On the other hand, the performance of the moisture absorbent-containing layer 28 of the humidity control device 21 in the first humidity control unit 20 gradually declines as the amount of moisture captured increases, so that a regeneration process must be performed. The regeneration process of the moisture absorbent-containing layer 28 of the humidity control device 21 is performed by applying a voltage to the pair of electrodes 27a, 27b and heating the honeycomb structure 22. Since the moisture absorbent-containing layer 28 is directly heated by heating the honeycomb structure 22, the moisture captured in the moisture absorbent-containing layer 28 is efficiently desorbed or reacted and released from the moisture absorbent-containing layer 28. A part of the released moisture is captured by the humidity control member 31 in the downstream second humidity control unit 30 in the initial stage of the regeneration process, so that it is possible to suppress high-humidity air from flowing all at once to the downstream side of the second humidity control unit 30. As a result, moisture is less likely to form water droplets and adhere to the air conditioning duct 10 downstream of the second humidity control unit 30. As the regeneration process of the moisture absorbent-containing layer 28 proceeds, the humidity control member 31 in the second humidity control unit 30 is also heated by the air heated by the humidity control device 21, and the amount of moisture released from the humidity control member 31 gradually increases. In order to obtain such an effect, the total amount of moisture absorbent in the second humidity control unit 30 needs to be 0.3 to 12 times the total amount of moisture absorbent in the first humidity control unit 20. If the total amount of moisture absorbent in the second humidity control unit 30 does not satisfy this range, the effect cannot be obtained sufficiently. Moreover, if the total amount of moisture absorbent in the second humidity control unit 30 is too large, the humidity control performance may decrease.

[0030] 3 shows a graph illustrating the relationship between the regeneration process time and the relative humidity in the air conditioning duct 10 in the presence or absence of the second humidity control unit 30. In FIG. 3, graph A shows the relative humidity in the air conditioning duct 10 downstream of the second humidity control unit 30 when the second humidity control unit 30 is provided downstream of the first humidity control unit 20 (note that the total amount of moisture absorbent in the second humidity control unit 30 is 0.3 to 12 times the total amount of moisture absorbent in the first humidity control unit 20). Graph B shows the relative humidity in the air conditioning duct 10 downstream of the first humidity control unit 20 when the second humidity control unit 30 is not provided downstream of the first humidity control unit 20. When the second humidity control unit 30 is not provided (graph B), the relative humidity peak is high and the peak width is small, which suggests that air with a high relative humidity flows into the air conditioning duct 10 all at once in a short period of time, making it easier for water droplets to adhere to the inside of the air conditioning duct 10. In contrast, when the second humidity control unit 30 is provided (graph A), the relative humidity peak is lower and the peak width is larger than in graph B, and it is thought that air with a reduced relative humidity flows gradually into the air conditioning duct 10, making it difficult for water droplets to adhere to the inside of the air conditioning duct 10.

[0031] Each component of the vehicle air conditioning system 100 will now be described in detail.

[0032] (1. Air conditioning duct 10) The air conditioning duct 10 is a flow path through which air can flow. The upstream side of the air conditioning duct 10 is connected to the vehicle cabin or an outside air inlet. The air conditioning duct 10 allows air to flow in from the vehicle cabin or outside the vehicle, and allows air that has passed through the first humidity control unit 20 and the second humidity control unit 30 to flow into the vehicle cabin or to be discharged outside the vehicle. Therefore, it is preferable that the air conditioning duct 10 has, downstream of the second humidity control unit 30, a first path 10a that allows air to flow into the vehicle cabin and a second path 10b that allows air to be discharged outside the vehicle.

[0033] The air conditioning duct 10 may have a switching valve 50 capable of switching the air flow between the first path 10a and the second path 10b. The switching valve 50 is not particularly limited as long as it is an electrically driven valve having the function of switching the flow path, and a solenoid valve, an electric valve, or the like may be used. For example, the switching valve 50 includes an opening / closing door supported on a rotating shaft, and an actuator such as a motor that rotates the rotating shaft. The actuator may be configured to be controllable by the control unit 60. In addition, a fan (not shown) for causing air from the vehicle compartment to flow into the first humidity control unit 20 and the second humidity control unit 30 may be provided inside the air conditioning duct 10. The position of the fan is not particularly limited, but may be provided upstream of the first humidity control unit 20, for example.

[0034] (2. First humidity control unit 20) The first humidity control unit 20 is a unit having one or more humidity control devices 21. The number of humidity control devices 21 is not particularly limited and may be appropriately set depending on the humidity control performance required. 2A and 2B, the humidity control device 21 includes a honeycomb structure 22 having an outer peripheral wall 23, partition walls 26 disposed inside the outer peripheral wall 23 and defining a plurality of cells 25 that serve as flow paths extending from a first end face 24a to a second end face 24b, a pair of electrodes 27a, 27b provided on the honeycomb structure 22, and a moisture absorbent-containing layer 28 formed on the surface of the partition wall 26. The humidity control device 21 may further include terminals 29 connected to the pair of electrodes 27a, 27b.

[0035] (2-1. Honeycomb structure 22) The shape of the honeycomb structure 22 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 25 extend) of the honeycomb structure 22 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 24a and second end face 24b) have the same shape as the cross section. When the cross section and the end faces are polygonal, the corners may be chamfered.

[0036] The shape of the cells 25 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 22. These shapes may be used alone or in combination of two or more. Among these shapes, a square or hexagon is preferable. By providing the cells 25 of such a shape, the pressure loss during air flow can be reduced.

[0037] The honeycomb structure 22 may be a honeycomb bonded body having a plurality of honeycomb segments and a bonding layer bonding the peripheral side surfaces of the plurality of honeycomb segments. By using the honeycomb bonded body, it is possible to increase the total cross-sectional area of ​​the cells 25, 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 a ceramic material with a solvent such as water added thereto to form a paste can be used. The bonding material may contain a material having PTC properties, or may contain the same material as the outer peripheral wall 23 and the partition walls 26. In addition to bonding the honeycomb segments together, the bonding material can also be used as an outer peripheral coating material after bonding the honeycomb segments.

[0038] From the standpoints of ensuring the strength of the honeycomb structure 22, reducing pressure loss when air passes through the cells 25, ensuring the amount of functional material carried, and ensuring the contact area with the air flowing within the cells 25, it is desirable to appropriately combine the thickness of the partition walls 26, the cell density, and the cell pitch (or the opening rate of the cells 25). 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 24a or second end face 24b) of the honeycomb structure 22 (the total area of ​​the partition walls 26 and the cells 25 excluding the outer wall 23). In this specification, the cell pitch refers to a value calculated by the following calculation. First, the area per cell is calculated by dividing the area of ​​one end face (first end face 24a or second end face 24b) of the honeycomb structure 22 (the total area of ​​the partition walls 26 and the cells 25 excluding the outer peripheral wall 23) 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 25 is a value obtained by dividing the total area of ​​the cells 25 partitioned by the partition walls 26 in a cross section perpendicular to the flow direction of the honeycomb structure 22 by the area of ​​one end face (the first end face 24a or the second end face 24b) (the total area of ​​the partition walls 26 and the cells 25 excluding the outer peripheral wall 23). Note that when calculating the opening ratio of the cells 25, the pair of electrodes 27a, 27b and the moisture absorbent-containing layer 28 are not taken into consideration.

[0039] In an embodiment advantageous from the viewpoint of carrying a sufficient amount of functional material, the thickness of the partition wall 26 is 0.300 mm or less, and the cell density is 100 cells / cm 2 In a preferred embodiment, the thickness of the partition wall 26 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 wall 26 is 0.130 mm or less, and the cell density is 65 cells / cm. 2 and the cell pitch is 1.3 mm or more.

[0040] From the viewpoint of ensuring the strength of the honeycomb structure 22 and keeping the electrical resistance low, the lower limit of the thickness of the partition walls 26 is preferably 0.010 mm or more, more preferably 0.020 mm or more, and further preferably 0.030 mm or more. From the viewpoints of ensuring the strength of the honeycomb structure 22, 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 viewpoints of ensuring the strength of the honeycomb structure 22, 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.

[0041] In an embodiment that is advantageous from the viewpoint of achieving both a reduction in pressure loss and a maintenance of strength, the partition walls 26 have a thickness of 0.08 to 0.36 mm and a cell density of 2.54 to 140 cells / cm. 2 In a preferred embodiment, the partition walls 26 have a thickness of 0.09 to 0.35 mm and a cell density of 15 to 100 cells / cm. 2In a more preferred embodiment, the partition walls 26 have a thickness of 0.14 to 0.30 mm and a cell density of 20 to 90 cells / cm. 2 , the aperture ratio of the cell 25 is 0.85 or more.

[0042] From the viewpoint of ensuring the strength of the honeycomb structure 22, the upper limit of the opening ratio of the cells 25 is preferably 0.94 or less, more preferably 0.92 or less, and further preferably 0.90 or less.

[0043] The thickness of the peripheral wall 23 is not particularly limited, but is preferably determined based on the following viewpoints. First, from the viewpoint of reinforcing the honeycomb structure 22, the thickness of the peripheral wall 23 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 from the viewpoint of reducing the pressure loss when air flows, the thickness of the peripheral wall 23 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 23 refers to the length in the normal direction of the side surface from the boundary between the peripheral wall 23 and the most peripheral cell 25 or partition wall 26 to the side surface of the honeycomb structure 22 in a cross section perpendicular to the flow path direction.

[0044] The length of the honeycomb structure 22 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 21. For example, when used in a compact humidity control device 21 while ensuring a predetermined function, the honeycomb structure 22 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.

[0045] The partition walls 26 constituting the honeycomb structure 22 are made of a material capable of generating heat when electricity is applied, specifically, made of a material having a PTC characteristic. If necessary, the outer peripheral wall 23 may also be made of a material having a PTC characteristic like the partition walls 26. With this configuration, it is possible to directly heat the moisture absorbent-containing layer 28 by heat transfer from the partition walls 26 (and the outer peripheral wall 23, if necessary) that generate heat. In addition, a material having a PTC characteristic has a characteristic that, when the temperature rises and exceeds the Curie point, the resistance value rises rapidly and it becomes difficult for electricity to flow. Therefore, when the partition walls 26 (and the outer peripheral wall 23, if necessary) become hot, the current flowing through them is limited, so that excessive heat generation of the honeycomb structure 22 is suppressed. Therefore, it is also possible to suppress thermal deterioration of the moisture absorbent-containing layer 28 caused by excessive heat generation.

[0046] From the viewpoint of obtaining an appropriate heat generation, the lower limit of the volume resistivity of the material having the PTC characteristics at 25°C is preferably 0.5 Ω·cm or more, more preferably 1 Ω·cm or more, and even more preferably 5 Ω·cm or more. From the viewpoint of generating heat at a low driving voltage, the upper limit of the volume resistivity of the material having the PTC characteristics at 25°C is preferably 30 Ω·cm or less, more preferably 18 Ω·cm or less, and even more preferably 16 Ω·cm or less. In this specification, the volume resistivity of the material having the PTC characteristics at 25°C is measured in accordance with JIS K6271:2008.

[0047] From the viewpoint of being able to generate heat when electricity is applied and having PTC characteristics, the outer peripheral wall 23 and the partition wall 26 are preferably made of a material mainly composed of barium titanate (BaTiO3). This material is more preferably a ceramic made of a material mainly composed of barium titanate (BaTiO3)-based crystal particles in which part of Ba is replaced with a rare earth element. In this specification, the term "main component" means 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 in a similar manner.

[0048] 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 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 suppressing 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 suppressing the electrical resistance at room temperature from becoming too high due to insufficient sintering. The content of BaTiO3-based crystal particles in the ceramics, in which a part of Ba is replaced by a rare earth element, is not particularly limited as long as it is the 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%.

[0049] From the viewpoint of reducing the environmental load, it is desirable that the material used for the outer peripheral wall 23 and the partition wall 26 does not substantially contain lead (Pb). Specifically, the Pb content of the outer peripheral wall 23 and the partition wall 26 is preferably 0.01 mass% or less, more preferably 0.001 mass% or less, and even more preferably 0 mass%. With a low Pb content, for example, air heated by contacting the partition wall 26 during heat generation can be safely applied to living organisms such as humans. Note that the Pb content of the outer peripheral wall 23 and the partition wall 26, calculated as PbO, is preferably less than 0.03 mass%, more preferably less than 0.01 mass%, and even more preferably 0 mass%. The lead content can be determined by ICP-MS (inductively coupled plasma mass spectrometry).

[0050] The Curie points of the materials constituting the outer peripheral wall 23 and the partition walls 26 are preferably in the temperature range in which the resistance value becomes at least twice the resistance value at room temperature (25° C.). If the Curie points are in such a temperature range, the current flowing through them is limited when the humidity control device 21 becomes hot, so that excessive heat generation in the humidity control device 21 is efficiently suppressed. Therefore, the thermal deterioration of the moisture absorbent-containing layer 28 caused by excessive heat generation can be suppressed. The lower limit of the Curie point of the material constituting the outer peripheral wall 23 and the partition wall 26 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 efficient heating of the moisture absorbent-containing layer 28. Meanwhile, 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.

[0051] The Curie point of the material constituting the outer peripheral wall 23 and the partition walls 26 can be adjusted by the type and amount of the shifter added. For example, the Curie point of barium titanate (BaTiO3) is about 120°C, but by substituting a part of Ba and Ti with one or more of Sr, Sn, and Zr, the Curie point can be shifted to the lower temperature side.

[0052] 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 tank (e.g., MINI-SUBZERO MC-810P, manufactured by Espec Corporation). The change in electrical resistance of the sample relative to the temperature change when the temperature is raised from 10°C is measured using a DC resistance meter (e.g., multimeter 3478A, manufactured by Hewlett-Packard Japan, LLC). The temperature at which the resistance value is twice the resistance value at room temperature (25°C) based on the electrical resistance-temperature plot obtained by the measurement is taken as the Curie point.

[0053] (2-2. Pair of electrodes 27a, 27b) The positions of the pair of electrodes 27a, 27b are not particularly limited, but may be provided on the first end face 24a and the second end face 24b as shown in Fig. 2A. The pair of electrodes 27a, 27b may also be provided on a pair of outer peripheral walls 23 parallel to the direction in which the cells 25 extend. By applying a voltage between the pair of electrodes 27a and 27b, it becomes possible to cause the honeycomb structure 22 to generate heat by Joule heat.

[0054] The pair of electrodes 27a, 27b 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. An ohmic electrode capable of making ohmic contact with the outer peripheral wall 23 and / or the partition wall 26 having PTC characteristics may also be used. The ohmic electrode may be, for example, an ohmic electrode containing 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 for n-type semiconductors as a dopant. The pair of electrodes 27a, 27b may have a single-layer structure or a laminated structure of two or more layers. When the pair of electrodes 27a, 27b has a laminated structure of two or more layers, the materials of the layers may be the same or different.

[0055] The thickness of the pair of electrodes 27a, 27b can be appropriately set depending on the method for forming the pair of electrodes 27a, 27b. Examples of the method for forming the pair of electrodes 27a, 27b include metal deposition methods such as sputtering, vapor deposition, electrolytic deposition, and chemical deposition. The pair of electrodes 27a, 27b can also be formed by applying an electrode paste and then baking it, or by thermal spraying. Furthermore, the pair of electrodes 27a, 27b may be formed by joining metal plates or alloy plates.

[0056] The thickness of the pair of electrodes 27a, 27b 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. In addition, in joining metal or alloy plates, the thickness is preferably about 5 to 100 μm.

[0057] (2-3. Terminal 29) Terminal 29 is connected to the pair of electrodes 27a, 27b and is provided on at least a part of the pair of electrodes 27a, 27b. Providing terminal 29 facilitates connection to an external power source. Terminal 29 is connected to a conductor connected to the external power source.

[0058] The material of the terminal 29 is not particularly limited, and may be, for example, a metal. As the metal, a simple metal or an alloy may be adopted, 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.

[0059] The size and shape of the terminal 29 are not particularly limited. For example, as shown in Fig. 2A, the terminal 29 may be provided on the entire pair of electrodes 27a, 27b on the outer peripheral wall 23. The terminal 29 may be provided on a part of the pair of electrodes 27a, 27b on the outer peripheral wall 23, or may be provided so as to extend outward beyond the outer edge of the pair of electrodes 27a, 27b on the outer peripheral wall 23. Furthermore, the terminal 29 may be provided on a part of the pair of electrodes 27a, 27b on the partition wall 26, or may be provided so as to cover some of the cells 25. The thickness of the terminal 29 is not particularly limited, but is, for example, 0.01 to 10 mm, typically 0.05 to 5 mm.

[0060] The method of connecting the terminal 29 and the pair of electrodes 27a, 27b 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.

[0061] (2-4. Moisture-absorbing material-containing layer 28) The moisture-absorbent material-containing layer 28 is a layer that contains a moisture-absorbent material, and has the function of adsorbing moisture (water vapor). The moisture absorbent-containing layer 28 can be provided on the surface of the partition wall 26 (in the case of the outermost cell 25, the partition wall 26 and the outer peripheral wall 23 that define the outermost cell 25). By providing the moisture absorbent-containing layer 28 in this manner, it becomes easier to heat the moisture absorbent-containing layer 28 during the regeneration process, so that the desired function of the moisture absorbent-containing layer 28 can be regenerated.

[0062] The moisture absorbent contained in the moisture absorbent-containing layer 28 preferably has a function of being able to adsorb moisture at -20 to 40°C and release it at a high temperature of 60°C or higher. Examples of moisture absorbents include, but are not limited to, aluminosilicates, silica gel, silica, graphene oxide, polymer adsorbents, polystyrene sulfonic acid, and metal organic frameworks (MOFs). These may be used alone or in combination of two or more.

[0063] As the aluminosilicate, it is preferable to use a porous clay mineral such as AFI-type, CHA-type or BEA-type zeolite, allophane, imogolite, etc. In addition, it is preferable that the aluminosilicate is amorphous.

[0064] 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, for example, sodium polyacrylate. The 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).

[0065] The moisture-absorbing material-containing layer 28 can contain a functional material having a function of adsorbing carbon dioxide and / or volatile components. By containing such a functional material, an air purification effect can be obtained in addition to an air dehumidification effect. The functional material preferably has a function capable of adsorbing carbon dioxide and / or volatile components at -20 to 40°C and releasing them at a high temperature of 60°C or higher. Examples of functional materials having such functions include zeolite, silica gel, activated carbon, alumina, silica, low-crystalline clay, and amorphous aluminum silicate complexes. The type of functional material may be appropriately selected depending on the type of components to be removed. The functional materials may be used alone or in combination of two or more.

[0066] The volatile components contained in the air in the vehicle cabin include, for example, volatile organic compounds (VOCs) and odor components other than VOCs. Specific examples of the 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.

[0067] The moisture absorbent-containing layer 28 may contain a catalyst. By containing a catalyst, it is possible to promote oxidation-reduction reactions and the like to purify 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. The catalyst may also be used in combination with the above-mentioned functional materials.

[0068] The thickness of the moisture-absorbent-containing layer 28 is not particularly limited and may be determined depending on the size of the cells 25. For example, the thickness of the moisture-absorbent-containing layer 28 is preferably 20 μm or more, more preferably 25 μm or more, and even more preferably 30 μm or more, from the viewpoint of ensuring sufficient contact with air. On the other hand, from the viewpoint of preventing the moisture-absorbent-containing layer 28 from peeling off from the partition walls 26 and the outer peripheral wall 23, the thickness of the moisture-absorbent-containing layer 28 is preferably 400 μm or less, more preferably 380 μm or less, and even more preferably 350 μm or less.

[0069] The thickness of the moisture absorbent-containing layer 28 is measured by the following procedure. An arbitrary cross section parallel to the flow path direction of the honeycomb structure 22 is cut out, and a cross-sectional image of about 50 times 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 of the honeycomb structure 22. For each moisture absorbent-containing layer 28 visible from the cross-sectional image, the thickness is calculated by dividing the cross-sectional area by the length of the cell 25 in the flow path direction. This calculation is performed for all moisture absorbent-containing layers 28 visible from the cross-sectional image, and the overall average value is regarded as the thickness of the moisture absorbent-containing layer 28.

[0070] From the viewpoint of exhibiting a desired function in the humidity control device 21, the amount of the moisture absorbent-containing layer 28 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 22. The volume of the honeycomb structure 22 is a value determined by the outer dimensions of the honeycomb structure 22.

[0071] (2-5. Manufacturing Method of Humidity Control Device 21) The method for producing the humidity control device 21 is not particularly limited and can be performed according to a known method. Hereinafter, the method for producing the humidity control device 21 will be described as an example. The method for manufacturing the honeycomb structure 22 constituting the humidity control device 21 includes a molding step and a firing step. In the forming step, a clay containing ceramic raw materials including BaCO3 powder, TiO2 powder, and powder of a rare earth nitrate or hydroxide is formed to produce a honeycomb formed body having a relative density of 60% or more. The ceramic raw material can be obtained by dry mixing each powder so as 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 necessary. The blending amount of components other than the ceramic raw materials is not particularly limited as long as the blending amount is such that the relative density of the honeycomb formed body is 60% or more.

[0072] 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 molded 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 actual volume (cm 3 ) can be calculated by dividing

[0073] The dispersion medium may be water or a mixed solvent of water and an organic solvent such as alcohol, with water being particularly preferred.

[0074] Examples of the binder include organic binders such as methyl cellulose, hydroxypropoxyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, and polyvinyl alcohol. In particular, it is preferable to use methyl cellulose and hydroxypropoxyl cellulose in combination. The binder may be used alone or in combination of two or more kinds, but it is preferable that the binder does not contain an alkali metal element.

[0075] Examples of the plasticizer include polyoxyalkylene alkyl ethers, polycarboxylic acid polymers, and alkyl phosphate esters.

[0076] 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 kinds.

[0077] The honeycomb formed body can be produced by extruding a clay. In the extrusion molding, a die having a desired overall shape, cell shape, partition wall thickness, cell density, etc. can be used.

[0078] The relative density of the honeycomb molded body obtained by extrusion molding is 60% or more, preferably 65% ​​or more. By controlling the relative density of the honeycomb molded body within this range, it is possible to densify the honeycomb molded body and reduce the electrical resistance at room temperature. The upper limit of the relative density of the honeycomb molded body is not particularly limited, but is generally 80%, preferably 75%.

[0079] 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 quickly and uniformly dry the entire molded body.

[0080] The firing step involves holding the material at 1150-1250° C., then increasing the temperature to a maximum temperature of 1360-1430° C. at a rate of 20-600° C. / hour, and holding the temperature for 0.5-10 hours. By holding the honeycomb formed body at a maximum temperature of 1360 to 1430° C. for 0.5 to 10 hours, it is possible to obtain a honeycomb structure 22 mainly composed of BaTiO3-based crystal grains in which part of Ba has been substituted with a rare earth element. Moreover, by maintaining the temperature at 1150 to 1250° C., Ba2TiO4 crystal particles generated during the firing process are easily removed, so that the honeycomb structure 22 can be densified. Furthermore, by setting the heating rate from 1150-1250°C to the maximum temperature of 1360-1430°C at 20-600°C / hour, 1.0-10.0 mass% of Ba6Ti 17 O 40 Crystal grains can be generated in the honeycomb structure 22 .

[0081] The holding time at 1150 to 1250° C. is not particularly limited, but is preferably 0.5 to 10 hours. By setting the holding time in this range, Ba2TiO4 crystal particles formed during the firing process can be stably and easily removed.

[0082] 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 22 having a predetermined composition.

[0083] A degreasing step may be carried out before the firing step to remove the binder. The degreasing step is preferably carried out in an air atmosphere in order to completely decompose the organic components. Moreover, it is preferable that the firing step be performed in an air atmosphere from the viewpoints of controlling electrical characteristics and reducing manufacturing costs. The firing furnace used in the firing step and the degreasing step is not particularly limited, but an electric furnace, a gas furnace, or the like can be used.

[0084] A pair of electrodes 27a, 27b are formed on the honeycomb structure 22 thus obtained. The pair of electrodes 27a, 27b can be formed by a metal deposition method such as sputtering, vapor deposition, electrolytic deposition, or chemical deposition. The pair of electrodes 27a, 27b can also be formed by applying an electrode paste and then baking it. Furthermore, the pair of electrodes 27a, 27b can also be formed by thermal spraying. The pair of electrodes 27a, 27b may be formed of a single layer, but may also be formed of multiple electrode layers with different compositions. A representative method for forming the pair of electrodes 27a, 27b will be described below.

[0085] First, an electrode slurry containing an electrode material, an organic binder, and a dispersion medium is prepared and applied to the first end face 24a or the second end face 24b of the honeycomb structure 22. The dispersion medium may 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 22 is removed by blowing and wiping. Thereafter, the slurry is dried to form a pair of electrodes 27a, 27b on the first end face 24a or the second end face 24b of the honeycomb structure 22. Drying may be performed while heating the honeycomb structure 22 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 the steps multiple times, a pair of electrodes 27a, 27b of a desired thickness can be provided.

[0086] Next, terminals 29 are placed at predetermined positions of the pair of electrodes 27a, 27b, and the pair of electrodes 27a, 27b are connected to the terminals 29. The method for connecting the pair of electrodes 27a, 27b to the terminals 29 can be the method described above. The terminal 29 may be provided after the moisture-absorbent material-containing layer 28 described below is formed.

[0087] Next, the moisture absorbent-containing layer 28 is formed on the surfaces of the partition walls 26 and the like of the honeycomb structure 22 . The method for forming the moisture absorbent-containing layer 28 is not particularly limited, but for example, the moisture absorbent-containing layer 28 can be formed by the following process. The honeycomb structure 22 is immersed in a slurry containing a moisture absorbent, an organic binder, and a dispersion medium for a predetermined time, and excess slurry on the end face and outer periphery of the honeycomb structure 22 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 absorbent-containing layer 28 on the surface of the partition wall 26. The drying can be performed while heating the honeycomb structure 22 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 a number of times, a moisture-absorbent-containing layer 28 of a desired thickness can be provided on the surfaces of the partition walls 26 and the like.

[0088] (3. Second humidity control unit 30) The second humidity control unit 30 is a unit having one or more humidity control members 31. The number of humidity control members 31 may be appropriately set depending on the number of humidity control devices 21 in the first humidity control unit 20 arranged upstream, and is not particularly limited.

[0089] The humidity control member 31 does not need to have a heater function because it is provided to prevent high-humidity air generated by heating the humidity control device 21 from flowing all at once into the air conditioning duct 10 in the early stage of the regeneration process. This is because if the humidity control member 31 is heated to a high temperature in the early stage of the regeneration process, high-humidity air will also be generated in the humidity control member 31. However, the humidity control member 31 may have a heater function, provided that the humidity control member 31 is not heated or is not heated to a high temperature in the early stage of the regeneration process.

[0090] The humidity control member 31 is not particularly limited, and a known one can be used. Examples of the humidity control member 31 include a moisture absorbent supported on a substrate of various shapes such as a sheet, mesh, or honeycomb. In addition, a moisture absorbent formed into various shapes such as a sheet, mesh, or honeycomb, or a moisture absorbent of various shapes filled in a housing may be used as the humidity control member 31. Among these, it is preferable that the humidity control member 31 has a honeycomb structure similar to the humidity control device 21. FIG. 4 shows a schematic diagram of a cross section parallel to the flow path direction of a humidity control member 31 having a honeycomb structure. 4, the humidity control member 31 includes a honeycomb structure 32 having an outer peripheral wall 33, partition walls 36 disposed inside the outer peripheral wall 33 and defining a plurality of cells 35 that serve as flow paths extending from a first end face 34a to a second end face 34b, and a moisture absorbent-containing layer 38 formed on the surface of the partition walls 36. By using the humidity control member 31 having such a structure, it is possible to stably obtain the effect of making it difficult for water droplets to adhere to the inside of the air conditioning duct 10 during the regeneration process, and to improve the moisture absorption performance.

[0091] Details of the honeycomb structure 32, such as its shape, are not particularly limited and may be the same as the honeycomb structure 22 used in the humidity control device 21. Therefore, hereinafter, only the features of the honeycomb structure 32 that differ from the honeycomb structure 22 used in the humidity control device 21 will be described. Unlike the honeycomb structure 22, the honeycomb structure 32 does not need to generate heat by passing an electric current through it. Therefore, the outer peripheral wall 33 and the partition walls 36 constituting the honeycomb structure 32 can be made of SiC, metal-bonded SiC, metal composite SiC, Si3N4, metal composite Si3N4, cordierite, mullite, spinel, alumina, zirconia, zirconia-reinforced alumina, etc. These can be used alone or in combination of two or more kinds. Here, examples of "metal-bonded SiC" include metal-impregnated SiC, Si-bonded SiC, and SiC bonded with metallic Si and other types of metals. Examples of "other types of metals" include Al (aluminum), Ni (nickel), Cu (copper), Ag (silver), Be (beryllium), Mg (magnesium), and Ti (titanium). Also, examples of "metal composite SiC" include SiC particles and metal powder mixed and sintered.

[0092] The honeycomb structure 32 has a partition wall 36 having a thickness of 0.06 to 0.40 mm and a cell density of 30 to 95 cells / cm. 2 It is preferable that the thickness of the partition wall 36 is 0.08 to 0.25 mm and the cell density is 40 to 80 cells / cm. 2 By controlling the thickness and cell density of the partition walls 36 within such ranges, it is possible to increase the moisture absorption performance while keeping the pressure loss low.

[0093] The type of moisture absorbent material used in the second humidity control unit 30 (humidity control member 31) may be the same as or different from the type of moisture absorbent material used in the humidity control device 21, but it is preferable that they are the same in consideration of manufacturability and manufacturing costs.

[0094] The total amount of moisture absorbent in the second humidity control unit 30 is 0.3 to 12 times the total amount of moisture absorbent in the first humidity control unit 20. By controlling the total amount of moisture absorbent in the second humidity control unit 30 within such a range, it is possible to improve the humidity control performance, and to prevent high humidity air from being captured by the humidity control member 31 in the second humidity control unit 30 in the initial stage of the regeneration process and flowing all at once to the downstream side of the second humidity control unit 30. From the viewpoint of stably ensuring this effect, the total amount of moisture absorbent in the second humidity control unit 30 is preferably 0.5 to 8 times, and more preferably 0.6 to 6 times, the total amount of moisture absorbent in the first humidity control unit 20.

[0095] The manufacturing method of the humidity control member 31 is not particularly limited and can be performed according to a known method. For example, when a humidity control member 31 having a honeycomb structure is used, the manufacturing method can be the same as the manufacturing method of the honeycomb structure 22 in the humidity control device 21 described above.

[0096] The second humidity control unit 30 is disposed in the air conditioning duct 10 adjacent to the first humidity control unit 20. The second humidity control unit 30 may or may not be in contact with the first humidity control unit 20. When the first humidity control unit 20 and the second humidity control unit 30 are not in contact with each other, high humidity air is captured by the humidity control member 31 in the second humidity control unit 30 in the initial stage of the regeneration process, and the effect of suppressing the air from flowing all at once to the downstream side of the second humidity control unit 30 can be enhanced.

[0097] When the first humidity control unit 20 and the second humidity control unit 30 are not in contact with each other, it is preferable that the distance between them is 10 cm or less. If the distance is within this range, moisture is less likely to remain between the first humidity control unit 20 and the second humidity control unit 30. In addition, it is preferable that the distance between the first humidity control unit 20 and the second humidity control unit 30 is 1 cm or more.

[0098] (4.Power supply 40) The power supply 40 is for applying a voltage to the pair of electrodes 27a, 27b. The power supply 40 is electrically connected to the control unit 60, and adjusts the state of the voltage applied to the pair of electrodes 27a, 27b in accordance with instructions from the control unit 60. The power source 40 is not particularly limited, and a battery or the like can be used.

[0099] (5. Control unit 60) The control unit 60 is connected to the power source 40, the switching valve 50, etc., and can control these. By controlling the power source 40, the control unit 60 can control the state of voltage application to the pair of electrodes 27a, 27b of the humidity control device 21, and adjust the heating state of the honeycomb structure 22. The control unit 60 can also control the switching valve 50 so that air flows through the first path 10a or the second path 10b. Furthermore, the control unit 60 can also be electrically connected to a fan (not shown) to control the fan.

[0100] The control unit 60 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.

[0101] It is preferable that the control unit 60 can execute a dehumidification mode in which the switching valve 50 is controlled to switch the air flow to the first path 10a to dehumidify the vehicle interior, and a regeneration mode in which a voltage is applied from the power source 40 to the pair of electrodes 27a, 27b of the humidity control device 21 and the switching valve 50 is controlled to switch the air flow to the second path 10b to regenerate the moisture absorbent. By executing the dehumidification mode and the regeneration mode in this manner, the dehumidification process and the regeneration process can be performed efficiently.

[0102] In the dehumidification mode, the control unit 60 switches the switching valve 50 so that air flows through the first path 10a, and starts the ventilator. By controlling in this way, air from the vehicle interior or outside the vehicle is dehumidified. At this time, the humidity control device 21 of the first humidity control unit 20 is not heated. Specifically, air from the vehicle interior or outside the vehicle flows through the air conditioning duct 10 and sequentially into the humidity control device 21 of the first humidity control unit 20 and the humidity control member 31 of the second humidity control unit 30, and moisture contained in the air is captured. Then, the dehumidified air is returned to the vehicle interior through the first path 10a.

[0103] In the regeneration mode, the control unit 60 switches the switching valve 50 so that air flows through the second path 10b, applies a voltage to the pair of electrodes 27a, 27b, and starts the fan. By controlling in this manner, the moisture absorbent-containing layer 28 of the humidity control device 21 in the first humidity control unit 20 is regenerated. Specifically, air from the vehicle compartment flows into the humidity control device 21 in the first humidity control unit 20 through the air conditioning duct 10, and while passing through the humidity control device 21, the moisture captured in the moisture absorbent-containing layer 28 is released. In addition, the air heated by the humidity control device 21 heats the humidity control member 31 in the second humidity control unit 30, and while passing through the humidity control member 31, the moisture captured in the humidity control member 31 is released. The moisture-containing air is then discharged to the outside of the vehicle through the second path 10b.

[0104] In the regeneration mode, in order to promote the desorption of moisture captured in the moisture absorbent-containing layer 28, it is preferable to heat the moisture absorbent-containing layer 28 to a temperature equal to or higher than the desorption temperature depending on the type of moisture absorbent. For example, it is preferable to heat the moisture absorbent-containing layer 28 to 70 to 150°C, more preferably to 80 to 140°C, and even more preferably to 90 to 130°C.

[0105] From the viewpoint of stably performing the above control, it is desirable that the humidity control device 21 of the first humidity control unit 20 is disposed at a position close to the vehicle interior. Therefore, from the viewpoint of preventing electric shock, etc., it is preferable that the driving voltage of the humidity control device 21 is 60 V or less. Since the honeycomb structure 22 used in the humidity control device 21 has low electrical resistance at room temperature, it is possible to heat the honeycomb structure 22 at this low driving voltage. The lower limit of the driving voltage is not particularly limited, but is preferably 10 V or more. If the driving voltage is less than 10 V, the current when the honeycomb structure 22 is heated will be large, and therefore it is necessary to use thicker conductors. EXAMPLES

[0106] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples in any way.

[0107] <Preparation of humidity control device> BaCO3 powder, TiO2 powder, and La(NH3)3·6H2O powder were prepared as ceramic raw materials. These powders were weighed so that the specified composition would be obtained after firing, and then dry-mixed to obtain a mixed powder. Dry mixing was carried out for 30 minutes. Next, water, binder, plasticizer, and dispersant were added in appropriate amounts in the range of 3 to 30 parts by mass in total to 100 parts by mass of the obtained mixed powder, and kneaded to obtain a clay body with a relative density of 64.8% after extrusion molding. Methylcellulose was used as the binder. Polyoxyalkylene alkyl ether was used as the plasticizer and dispersant.

[0108] Next, the obtained clay was put into an extrusion molding machine and extrusion molded using a predetermined die so as to obtain a honeycomb structure having the shape shown below after firing. Cross section and end face shape of honeycomb structure perpendicular to the flow direction: Rectangular Shape of cell cross section perpendicular to flow direction: Square Partition thickness: 0.1mm Outer wall thickness: 0.2mm Cell density: 80 cells / cm 2 Cell pitch: 1.1mm Cross-sectional area perpendicular to the direction of extension of the flow passage of the honeycomb structure: 6000 mm 2 Length of the honeycomb structure in the direction of flow: 10 mm Volume resistivity of the material that composes the outer wall and partition at 25°C: 15 Ω cm Curie point of the material constituting the outer wall and partition wall: 110°C

[0109] Next, the obtained honeycomb molded body was subjected to dielectric drying and hot air drying, and then degreased in an air atmosphere in a firing furnace (450°C x 4 hours), and then fired in an air atmosphere to obtain a honeycomb structure. The firing was performed by holding at 950°C for 1 hour, then increasing the temperature to 1200°C and holding at 1200°C for 1 hour, then increasing the temperature to 1400°C (maximum temperature) at a heating rate of 200°C / hour, and holding at 1400°C for 2 hours.

[0110] Next, a pair of electrodes was formed on both end faces (first end face and second end face) of the obtained honeycomb structure. First, an electrode slurry containing aluminum (electrode material), ethyl cellulose, and diethylene glycol monobutyl ether (organic binder) was prepared and applied to the first end face, and then the electrode slurry was dried to form an electrode on the surface of the first end face. In addition, the same electrode slurry was used to apply the electrode slurry to the second end face and dry it to form an electrode on the second end face.

[0111] Next, the honeycomb structure on which the pair of electrodes was formed was immersed in a slurry containing zeolite (moisture absorbent), an organic binder, and water, and the slurry adhering to unnecessary positions (such as the periphery) was removed by blowing and wiping, and then the structure was dried at a temperature of about 550° C. to form a moisture absorbent-containing layer of a predetermined thickness on the surface of the partition walls and the surface of the peripheral wall facing the cells. The thickness of the moisture absorbent-containing layer was controlled by adjusting the number of times of a series of steps of immersion, slurry removal, and drying.

[0112] <Production of humidity control material> A cordierite raw material containing a mixture of alumina, kaolin, and talc was used as a ceramic raw material, and a binder containing an organic binder, a water-absorbent resin as a pore-forming material, and water as a dispersion medium were mixed with the cordierite raw material to form a raw material composition, which was then kneaded to obtain a clay. The resulting clay was then extrusion-molded to obtain a honeycomb molded body having cells. The honeycomb molded body was extrusion-molded using a specified die so as to become a honeycomb structure having the shape shown below after firing. Cross section and end face shape of honeycomb structure perpendicular to the flow direction: Rectangular Shape of cell cross section perpendicular to flow direction: Square Partition thickness: 0.1mm Outer wall thickness: 0.2mm Cell density: 70 cells / cm 2 Cross-sectional area perpendicular to the direction of extension of the flow passage of the honeycomb structure: 6000 mm 2 Length of the honeycomb structure in the direction of flow: 10 mm

[0113] Next, the obtained honeycomb molded body was subjected to dielectric drying and hot air drying, and then degreased in an air atmosphere in a firing furnace (450°C x 4 hours), and then fired in an air atmosphere (1370°C x 6 hours) to obtain a honeycomb structure.

[0114] Next, the obtained honeycomb structure was immersed in a slurry containing zeolite (moisture absorbent), an organic binder, and water, and the slurry adhering to unnecessary positions (such as the periphery) was removed by blowing and wiping, and then the structure was dried at a temperature of about 550° C. to form a moisture absorbent-containing layer of a predetermined thickness on the surface of the partition walls and the surface of the peripheral wall facing the cells. The thickness of the moisture absorbent-containing layer was controlled by adjusting the number of times of a series of steps of immersion, slurry removal, and drying.

[0115] <Examples 1 to 12 and Comparative Example 2> A humidity control device (first humidity control unit) and a humidity control member (second humidity control unit) were placed in a transparent air conditioning duct from the upstream side, and a DC power supply was connected to a pair of electrodes of the humidity control device to prepare a vehicle air conditioning system. The ratio of the total amount of the humidity control member to the total amount of the moisture absorbent in the humidity control device of each example and each comparative example (hereinafter sometimes abbreviated as "total amount ratio of moisture absorbent") and the distance between the humidity control device and the humidity control member (hereinafter sometimes abbreviated as "unit distance") were set as shown in Table 1. In addition, a fan was placed in the air conditioning duct upstream of the humidity control device.

[0116] <Comparative Example 1> A vehicle air conditioning system (conventional example) was fabricated by placing only the humidity control device (first humidity control unit) from the upstream side in a transparent air conditioning duct and connecting a DC power supply to a pair of electrodes of the humidity control device. In addition, a fan was placed in the air conditioning duct upstream of the humidity control device.

[0117] The vehicle air conditioning systems of the examples and comparative examples obtained above were evaluated as follows.

[0118] <Dehumidification performance> The vehicle air conditioning system was subjected to the regeneration mode and then the dehumidification mode. The regeneration mode was performed by starting the fan to circulate air at a temperature of 25°C and a relative humidity of 40% through the air conditioning duct at a flow rate of 20 L / min, while applying a voltage of 12 V from a DC power supply to the humidity control device for 4 minutes. The dehumidification mode was performed by not applying a voltage to the humidity control device and circulating air under the same conditions through the air conditioning duct at a flow rate of 300 L / min. In the dehumidification mode, the absolute humidity was recorded by humidity sensors placed before and after the humidity control device, and the amount of moisture removed was calculated. In this evaluation, the result of Comparative Example 1 was used as the standard, and the improvement rate of the results of each Example and Comparative Example relative to the standard was calculated. An improvement rate of 8% or more was designated as A, an improvement rate of 5% or more but less than 8% was designated as B, an improvement rate of 2% or more but less than 5% was designated as C, and an improvement rate of less than 2% (same level as Comparative Example 1) was designated as D. Note that if the improvement rate is 2% or more, it can be said that the dehumidification performance is improved compared to the conventional vehicle air conditioning system.

[0119] <Water droplet adhesion prevention performance> In the above dehumidification performance test, whether water droplets were attached inside the transparent air conditioning duct was visually evaluated. In this evaluation, a transparent air conditioning duct with no water droplets attached thereto was designated as A, an air conditioning duct with water droplets attached thereto downstream of the humidity control component was designated as Z, and an air conditioning duct with water droplets attached thereto between the humidity control device and the humidity control component was designated as Y. The above evaluation results are shown in Table 1.

[0120] [Table 1]

[0121] As shown in Table 1, in Examples 1 to 12, the total amount of moisture absorbent in the humidity control member (second humidity control unit) was 0.3 to 12 times the total amount of moisture absorbent in the humidity control device (first humidity control unit), and therefore both the dehumidification performance and the water droplet adhesion prevention performance were good. In contrast to this, in Comparative Example 1 (conventional example), since no humidity control member (second humidity control unit) was provided, the water droplet adhesion prevention performance was insufficient. In Comparative Example 2, the total amount of moisture absorbent in the humidity control member (second humidity control unit) was less than 0.3 times the total amount of moisture absorbent in the humidity control device (first humidity control unit), so both the dehumidification performance and the water droplet adhesion prevention performance were insufficient.

[0122] As can be seen from the above results, the present invention can provide a vehicle air conditioning system in which water droplets are less likely to adhere to the inside of the air conditioning duct during regeneration processing. [Explanation of symbols]

[0123] 10 Air conditioning duct 10a Route 1 10b Pathway 2 20 First humidity control unit 21 Humidity Control Device 22 Honeycomb structure 23 Outer wall 24a 1st end face 24b 2nd end face 25 cells 26 Bulkhead 27a, 27b A pair of electrodes 28 Hygroscopic material containing layer 29 Terminals 30 Second humidity control unit 31 Humidity control materials 32 Honeycomb structure 33 Outer wall 34a 1st end face 34b 2nd end face 35 Cells 36 Bulkhead 38 Hygroscopic material containing layer 40 Power supply 50 Switching valve 60 Control section

Claims

1. An air conditioning duct through which air can flow; a honeycomb structure having an outer peripheral wall and partition walls disposed inside the outer peripheral wall and partitioning a plurality of cells that become flow paths extending from a first end face to a second end face, the partition walls being made of a material having a PTC characteristic; and a first humidity control unit disposed in the air conditioning duct, the first humidity control unit having one or more humidity control devices including a pair of electrodes provided on the honeycomb structure and a moisture absorbent-containing layer formed on a surface of the partition walls; a second humidity control unit having one or more humidity control members including a moisture absorbent and disposed in the air conditioning duct downstream of the first humidity control unit; a power source for applying a voltage to the humidity control device; Equipped with A vehicle air conditioning system, wherein a total amount of the moisture absorbent in the second humidity control unit is 0.3 to 12 times a total amount of the moisture absorbent in the first humidity control unit.

2. 2. The vehicle air conditioning system according to claim 1, wherein the humidity control member includes a honeycomb structure having an outer peripheral wall and partition walls arranged inside the outer peripheral wall and defining a plurality of cells that serve as flow paths extending from a first end face to a second end face, and a moisture absorbent-containing layer formed on a surface of the partition walls.

3. The humidity control member has a partition wall thickness of 0.06 to 0.40 mm and a cell density of 30 to 95 cells / cm. 2 3. The vehicle air conditioning system according to claim 2, wherein:

4. 4. The vehicle air conditioning system according to claim 1, wherein the humidity control member does not have a heater function.

5. 4. The vehicle air conditioning system according to claim 1, wherein a total amount of the moisture absorbent in the second humidity control unit is 0.5 to 8 times a total amount of the moisture absorbent in the first humidity control unit.

6. 4. The vehicle air conditioning system according to claim 1, wherein a total amount of the moisture absorbent in the second humidity control unit is 0.6 to 6 times a total amount of the moisture absorbent in the first humidity control unit.

7. The vehicle air conditioning system according to any one of claims 1 to 3, wherein the humidity control device is provided with the pair of electrodes on the first end surface and the second end surface.

8. 4. The vehicle air conditioning system according to claim 1, wherein a distance between the first humidity control unit and the second humidity control unit is 10 cm or less.

9. the air conditioning duct has, downstream of the second humidity control unit, a first passage for introducing the air into a vehicle compartment and a second passage for discharging the air to the outside of the vehicle; 4. The vehicle air conditioning system according to claim 1, further comprising a switching valve capable of switching the flow of the air between the first path and the second path.

10. a dehumidification mode in which the switching valve is controlled to switch the flow of the air to the first path, thereby dehumidifying the interior of the vehicle cabin; a regeneration mode in which a voltage is applied from the power source to the pair of electrodes of the humidity control device and the switching valve is controlled to switch the flow of the air to the second path, thereby regenerating the moisture absorbent; The vehicle air conditioning system according to claim 9 , further comprising a control unit capable of executing the above-mentioned steps.

11. 4. The vehicle air conditioning system according to claim 1, wherein the material having PTC properties is mainly composed of barium titanate.

12. The vehicle air conditioning system according to any one of claims 1 to 3, wherein the moisture absorbent layer of the humidity control device further contains a functional material having a function of adsorbing at least one selected from carbon dioxide and a volatile component, and / or a catalyst.

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