Vehicle air conditioning system and method for controlling the same

Abstract

To provide a vehicle air conditioning system using a heat pump cycle that is excellent in heating efficiency and immediate warming property during a cold weather, can remove moisture content from the air of a cabin, and can be miniaturized, and to provide a method for controlling the same.SOLUTION: A vehicle air conditioning system includes: an air conditioning duct 10 through which air can circulate; a humidity conditioning device 20 disposed in the air conditioning duct 10; a heat pump cycle 30 including a condenser 31 disposed in the air conditioning duct 10 on a downstream side of the humidity conditioning device 20; and a controller 40 for controlling the humidity conditioning device 20 and the heat pump cycle 30 in accordance with an operation mode. The controller 40 includes an air warming mode of warming air with the humidity conditioning device 20 at the time of starting a heating operation mode of the heat pump cycle 30.SELECTED DRAWING: Figure 1A

Description

[Technical Field]

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

[0002] There is a growing demand for improved cabin environments in automobiles and other vehicles. Specific requirements include reducing CO2 emissions in the cabin to suppress driver drowsiness, controlling humidity in the cabin, and removing harmful volatile components such as odorous components and allergy-inducing substances from the cabin. Ventilation is an effective solution to these requirements, 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: the driving range is significantly reduced.

[0003] As a method for solving the above problems, Patent Documents 1 and 2 disclose a vehicle air conditioning system that captures target components, such as moisture (water vapor) and CO2, in the air in the vehicle cabin using a functional material such as an adsorbent, and then heats the target components to react or desorb and release them outside the vehicle, thereby regenerating the functional material. Such vehicle air conditioning systems require as much contact between the air and the functional material as possible to ensure the target components' capture performance, and also require the functional material to be able to be heated to a predetermined temperature to promote regeneration. Regeneration can be achieved, for example, by removing the target components adsorbed on the functional material through an oxidation reaction, or by desorbing and discharging the target components adsorbed on the functional material. In either case, the functional material must be heated to an appropriate temperature depending on the type of adsorbed target components.

[0004] Patent Document 3 discloses a heater element having a columnar honeycomb structure including an outer peripheral wall and partition walls disposed inside the outer peripheral wall and defining a plurality of cells that form a flow path from the first end face to the second end face, the partition walls having PTC characteristics, an average thickness of 0.13 mm or less, and an aperture ratio of 0.81 or more at the first end face and the second end face. This heater element is used for heating vehicle cabins, and the honeycomb structure allows for a large heating area, making it an efficient heating means. Therefore, using such a heater element as a carrier for a functional material is thought to contribute to shortening the regeneration time of the functional material. In particular, this heater element can be heated by electrical current and has PTC (Positive Temperature Coefficient) characteristics, so it can easily heat the functional material while suppressing excessive heat generation and thermal degradation of the functional material. Furthermore, because the risk of excessive temperature is avoided, safety can be ensured even if the initial resistance is set low and the heating rate is increased, and temperature can be raised in a short time.

[0005] On the other hand, air conditioning systems using a heat pump cycle are known from the viewpoint of improving heating efficiency and reducing power consumption. However, these air conditioning systems lack sufficient heating efficiency and quick heating in cold temperatures such as below freezing. Therefore, it has been proposed to use a PTC heater as an auxiliary heat source (for example, Patent Document 4). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2020-104774 [Patent Document 2] Japanese Patent Application Publication No. 2020-111282 [Patent Document 3] International Publication No. 2020 / 036067 [Patent Document 4] International Publication No. 2011 / 016264 Summary of the Invention [Problem to be solved by the invention]

[0007] In a vehicle air conditioning system that uses a heat pump cycle, it is preferable to install a PTC heater as an auxiliary heat source from the viewpoints of heating efficiency and quick warming in cold weather, and to install a humidity control device from the viewpoint of removing moisture from the air in the vehicle cabin. However, installing both a PTC heater and a humidity control device in a vehicle air conditioning system results in the vehicle air conditioning system becoming larger.

[0008] The present invention has been made to solve the above-mentioned problems, and aims to provide a vehicle air conditioning system that uses a heat pump cycle, has excellent heating efficiency and quick heating in cold weather, can remove moisture from the air in the vehicle cabin, and can be made compact, and a control method for the same. [Means for solving the problem]

[0009] As a result of extensive research into vehicle air conditioning systems that utilize a heat pump cycle, the inventors discovered that by placing a specific humidity control device in an air conditioning duct and using the humidity control device to heat the air when the heating operation mode of the heat pump cycle is started, it is possible to improve heating efficiency and quick heating in cold weather, thereby eliminating the need for a PTC heater and enabling miniaturization, leading to the completion of the present invention. That is, the present invention is exemplified as follows.

[0010] [1] An air conditioning duct through which air can flow; a humidity control device disposed in the air conditioning duct; a heat pump cycle including a condenser disposed in the air conditioning duct downstream of the humidity control device; a control unit that controls the humidity control device and the heat pump cycle according to an operation mode; Equipped with the humidity control device includes 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 flow paths extending from a first end face to a second end face, at least the partition walls being made of a material having PTC properties; and a moisture absorbing layer formed on a surface of the partition walls, The vehicle air conditioning system includes a warm-up mode in which the control unit heats the air using the humidity control device when a heating operation mode of the heat pump cycle starts.

[0011] [2] The vehicle air conditioning system according to [1], wherein the humidity control device heats the air within 10 minutes from the start of the heating operation mode of the heat pump cycle.

[0012] [3] The vehicle air conditioning system according to [1] or [2], wherein the heating of the air by the humidity control device is stopped when the heating COP of the heat pump cycle reaches a predetermined value of 1.0 or more.

[0013] [4] The air conditioning duct has, between the humidity control device and the condenser, an inflow path for introducing the air into the vehicle compartment and an outflow path for discharging the air to the outside of the vehicle, and a valve capable of switching the flow of the air is provided between the inflow path and the outflow path, The vehicle air conditioning system according to any one of [1] to [3], wherein the condenser is disposed in the inflow path.

[0014] [5] The warm-up mode of the humidity control device is performed by controlling the valve to allow the air to flow into the inlet path and circulating the air while applying voltage to the humidity control device. [4] A vehicle air conditioning system as described in [4].

[0015] [6] The humidity control device a dehumidification mode in which the valve is controlled to allow the air to flow into the inflow path and the air is dehumidified by circulating the air through the humidity control device; and a regeneration mode in which the valve is controlled to allow the air to flow into the outflow path, and the humidity control device is heated while the air is circulated to regenerate the moisture absorption layer; The vehicle air conditioning system according to [4] or [5], further comprising at least one operating mode selected from the following:

[0016] [7] The heat pump cycle further includes a compressor that compresses and discharges a refrigerant, The vehicle air conditioning system according to any one of [1] to [6], wherein the heating operation mode of the heat pump cycle includes introducing the refrigerant discharged from the compressor into the condenser to heat the air.

[0017] [8] 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 wall of the honeycomb structure that is parallel to the direction in which the cells extend. This is an air conditioning system for a vehicle described in any one of [1] to [7].

[0018] [9] The vehicle air conditioning system according to any one of [1] to [8], wherein the moisture absorption layer is capable of adsorbing carbon dioxide and / or volatile components in addition to moisture.

[0019]

[10] an air conditioning duct through which air can flow; a humidity control device disposed in the air conditioning duct; a heat pump cycle including a condenser disposed in the air conditioning duct downstream of the humidity control device; Equipped with In a vehicle air conditioning system, the humidity control device includes a honeycomb structure having an outer peripheral wall and partition walls disposed inside the outer peripheral wall to define a plurality of cells that become flow paths extending from a first end face to a second end face, at least the partition walls being made of a material having PTC properties, and a moisture absorption layer formed on a surface of the partition walls, A control method for a vehicle air conditioning system, comprising a warm-up mode in which the air is heated by the humidity control device at the start of a heating operation mode of the heat pump cycle.

[0020]

[11] The method for controlling a vehicle air conditioning system according to

[10] , wherein the humidity control device heats the air within 10 minutes from the start of the heating operation mode of the heat pump cycle.

[0021]

[12] A method for controlling a vehicle air conditioning system according to

[10] or

[11] , wherein the heating of the air by the humidity control device is stopped when the heating COP of the heat pump cycle reaches a predetermined value of 1.0 or more.

[0022]

[13] The air conditioning duct has, between the humidity control device and the condenser, an inflow path for introducing the air into the vehicle compartment and an outflow path for discharging the air to the outside of the vehicle, and a valve capable of switching the flow of the air is provided between the inflow path and the outflow path, The method for controlling a vehicle air conditioning system according to any one of

[10] to

[12] , wherein the condenser is disposed in the inflow path.

[0023]

[14] The warm-up mode of the humidity control device is performed by controlling the valve to allow the air to flow into the inlet path and circulating the air while applying a voltage to the humidity control device. This is a control method for a vehicle air conditioning system as described in

[13] .

[0024]

[15] The humidity control device a dehumidification mode in which the valve is controlled to allow the air to flow into the inflow path and the air is dehumidified by circulating the air through the humidity control device; and a regeneration mode in which the valve is controlled to allow the air to flow into the outflow path, and the humidity control device is heated while the air is circulated to regenerate the moisture absorption layer; The method for controlling a vehicle air conditioning system according to

[13] or

[14] , further comprising at least one operation mode selected from the following:

[0025]

[16] The heat pump cycle further includes a compressor that compresses and discharges a refrigerant, The control method for a vehicle air conditioning system according to any one of

[10] to

[15] , wherein the heating operation mode of the heat pump cycle includes introducing the refrigerant discharged from the compressor into the condenser to heat the air. [Effects of the Invention]

[0026] According to the present invention, it is possible to provide a vehicle air conditioning system and a control method thereof that utilizes a heat pump cycle, which has excellent heating efficiency and quick heating in cold weather, can remove moisture and other substances from the air in the vehicle cabin, and can be made compact. [Brief explanation of the drawings]

[0027] [Figure 1A] 1 is a schematic diagram of a vehicle air conditioning system according to an embodiment of the present invention, showing an operating state in a warm-up / heating operation mode. [Figure 1B] 1 is a schematic configuration diagram of a vehicle air conditioning system according to an embodiment of the present invention, illustrating an operating state in a dehumidifying / cooling operation mode. [Figure 1C] 1 is a schematic configuration diagram of a vehicle air conditioning system according to an embodiment of the present invention, illustrating an operating state in a dehumidifying / cooling operation mode. [Figure 1D] 1 is a schematic diagram of a vehicle air conditioning system according to an embodiment of the present invention, illustrating an operating state in a regeneration / non-cooling / heating operation mode. [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 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 aa'. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0028] The vehicle air conditioning system of the present invention includes an air conditioning duct through which air can flow, a humidity control device disposed in the air conditioning duct, a heat pump cycle including a condenser disposed in the air conditioning duct downstream of the humidity control device, and a control unit that controls the humidity control device and the heat pump cycle depending on the operating mode. The humidity control device includes a honeycomb structure having an outer peripheral wall and partition walls disposed inside the outer peripheral wall and defining a plurality of cells that form flow paths extending from a first end face to a second end face, at least the partition walls being made of a material having PTC characteristics, and a moisture absorption layer formed on the surface of the partition walls. The control unit includes a warm-air mode in which the humidity control device heats the air when the heating operation mode of the heat pump cycle begins. This configuration of the vehicle air conditioning system of the present invention provides excellent heating efficiency and quick warm-up in cold weather, eliminating the need for a PTC heater and enabling miniaturization. Furthermore, the vehicle air conditioning system, equipped with the humidity control device, can also remove moisture from the air in the vehicle cabin.

[0029] The present invention also provides a method for controlling a vehicle air conditioning system, which includes a heat pump cycle including an air conditioning duct through which air can flow, a humidity control device disposed in the air conditioning duct, and a condenser disposed in the air conditioning duct downstream of the humidity control device. The humidity control device has an outer peripheral wall and partition walls disposed inside the outer peripheral wall, which partition a plurality of cells forming flow paths extending from a first end face to a second end face. The humidity control device includes a honeycomb structure in which at least the partition walls are made of a material having PTC characteristics, and a moisture absorption layer formed on the surface of the partition wall. The vehicle air conditioning system includes a warm-up mode in which air is heated by the humidity control device at the start of the heating operation mode of the heat pump cycle. This configuration of the vehicle air conditioning system control method of the present invention improves heating efficiency and quick heating in cold weather, even without a PTC heater. Furthermore, because the vehicle air conditioning system includes a humidity control device, it can also remove moisture from the air in the vehicle cabin.

[0030] 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.

[0031] <Vehicle air conditioning system> A vehicle air conditioning system according to an embodiment of the present invention is 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 an embodiment of the present invention is particularly suitable for use in vehicles without internal combustion engines, such as electric vehicles and trains.

[0032] 1A to 1D are schematic diagrams of a vehicle air conditioning system according to an embodiment of the present invention, showing the operating state in each operation mode. In particular, FIG. 1A shows the warming / heating operation mode, FIGS. 1B and 1C show the dehumidifying / cooling operation mode, and FIG. 1D shows the regeneration / non-cooling / heating / non-heating operation mode. Note that the dehumidifying / heating operation mode is the same as FIG. 1, and therefore is omitted. FIG. 2A 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 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.

[0033] A vehicle air conditioning system according to an embodiment of the present invention includes an air conditioning duct 10, a humidity control device 20, a heat pump cycle 30, and a control unit 40. The vehicle air conditioning system may further include a power supply 50, a ventilator 60, and an air mix door 70. Each of these components will be described in detail below.

[0034] (1. Air conditioning duct 10) The air conditioning duct 10 is a pipe through which air can flow from the vehicle interior or outside the vehicle. The shape and size of the air conditioning duct 10 may be adjusted appropriately depending on the type of vehicle, and are not particularly limited. It is preferable that the air conditioning duct 10 has, between the humidity control device 20 and the condenser 31 of the heat pump cycle 30, an inlet path 11 for allowing air to flow into the vehicle compartment and an outlet path 12 for allowing air to flow out of the vehicle.

[0035] It is preferable that a valve 13 capable of switching the flow of air is provided between the inflow path 11 and the outflow path 12. The valve 13 can be provided at the branch point of the inflow path 11 and the outflow path 12. The valve 13 can be switched, for example, by electrically connecting the control unit 40 and the valve 13 by wire or wirelessly and operating the switch of the valve 13 with the control unit 40. The valve 13 is not particularly limited as long as it is electrically driven and has the function of switching the flow path, and examples thereof include a solenoid valve and an electric valve. For example, the valve 13 may include an opening / closing door supported on a rotating shaft and an actuator such as a motor that rotates the rotating shaft. The actuator is configured to be controllable by the control unit 40.

[0036] (2. Humidity Control Device 20) The humidity control device 20 is disposed in the air conditioning duct 10. The humidity control device 20 includes a honeycomb structure 25 having an outer peripheral wall 21 and partition walls 24 disposed inside the outer peripheral wall 21 and defining a plurality of cells 23 that serve as flow paths extending from a first end face 22a to a second end face 22b, at least the partition walls 24 being made of a material having PTC properties, and a moisture absorbing layer 26 formed on the surface of the partition walls 24. The humidity control device 20 can further include a pair of electrodes 27a, 27b for applying a voltage to the honeycomb structure 25, and a terminal 28 connected to the pair of electrodes 27a, 27b.

[0037] When air from the vehicle interior or outside flows into the humidity control device 20 through the air conditioning duct 10, moisture in the air is captured (removed) by the moisture absorption layer 26 while passing through the humidity control device 20. Then, the air with reduced moisture content can flow into the vehicle interior through the inflow path 11. On the other hand, the performance of the moisture absorption layer 26 gradually deteriorates as the amount of moisture it captures increases, and therefore the moisture absorption layer 26 must be regenerated. The moisture absorption layer 26 is regenerated by applying a voltage to the pair of electrodes 27a, 27b using a power supply 50 controlled by the control unit 40, thereby heating the honeycomb structure 25. Since the moisture absorption layer 26 is directly heated by heating the honeycomb structure 25, the moisture captured in the moisture absorption layer 26 is efficiently desorbed or reacted from the moisture absorption layer 26 and can be released to the outside of the vehicle via the outflow path 12.

[0038] (2-1. Honeycomb structure 25) The shape of the honeycomb structure 25 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 23 extend) of the honeycomb structure 25 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 22a and second end face 22b) have the same shape as the cross section. When the cross section and end faces are polygonal, the corners may be chamfered.

[0039] The shape of the cells 23 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 25. 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 23 of such a shape, pressure loss during air flow can be reduced.

[0040] The honeycomb structure 25 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 23, 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 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 21 and the partition walls 24. In addition to the role of bonding the honeycomb segments together, the bonding material can also be used as an outer peripheral coating material after bonding the honeycomb segments.

[0041] From the viewpoints of ensuring the strength of the honeycomb structure 25, reducing pressure loss when air passes through the cells 23, ensuring the loading amount of the moisture absorption layer 26, and ensuring the contact area with the air flowing within the cells 23, it is desirable to suitably combine the thickness of the partition walls 24, the cell density, and the cell pitch (or the opening rate of the cells 23). 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 22a or second end face 22b) of the honeycomb structure 25 (the total area of the partition walls 24 and cells 23 excluding the outer wall 21). 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 22a or second end face 22b) of the honeycomb structure 25 (the total area of the partition walls 24 and the cells 23 excluding the outer peripheral wall 21) 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 23 is a value obtained by dividing the total area of the cells 23 partitioned by the partition walls 24 in a cross section perpendicular to the flow direction of the honeycomb structure 25 by the area of one end face (the first end face 22a or the second end face 22b) (the total area of the partition walls 24 and the cells 23 excluding the outer peripheral wall 21). Note that when calculating the opening ratio of the cells 23, the pair of electrodes 27a, 27b and the moisture absorption layer 26 are not taken into consideration.

[0042] In an embodiment advantageous from the viewpoint of carrying a sufficient amount of the moisture-absorbing layer 26, the thickness of the partition wall 24 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 24 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 24 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.

[0043] From the viewpoint of ensuring the strength of the honeycomb structure 25 and keeping the electrical resistance low, the lower limit of the thickness of the partition walls 24 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 25, 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 25, 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.

[0044] In an embodiment that is advantageous from the viewpoint of achieving both a reduction in pressure loss and maintaining strength, the thickness of the partition walls 24 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 24 is 0.09 to 0.35 mm, and the cell density is 15 to 100 cells / cm. 2In a more preferred embodiment, the thickness of the partition walls 24 is 0.14 to 0.30 mm, and the cell density is 20 to 90 cells / cm. 2 The aperture ratio of the cell 23 is 0.85 or more.

[0045] From the viewpoint of ensuring the strength of the honeycomb structure 25, the upper limit of the opening ratio of the cells 23 is preferably 0.94 or less, more preferably 0.92 or less, and further preferably 0.90 or less.

[0046] The thickness of the peripheral wall 21 is not particularly limited, but is preferably determined based on the following points: First, from the viewpoint of reinforcing the honeycomb structure 25, the thickness of the peripheral wall 21 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 when air flows through, the thickness of the peripheral wall 21 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 21 refers to the length in the normal direction of the side surface of the honeycomb structure 25 from the boundary between the peripheral wall 21 and the outermost cell 23 or partition wall 24 to the side surface of the honeycomb structure 25 in a cross section perpendicular to the flow direction of the honeycomb structure 25.

[0047] The length of the honeycomb structure 25 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 20. For example, when used in a compact humidity control device 20 while ensuring a predetermined function, the honeycomb structure 25 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.

[0048] The partition walls 24 constituting the honeycomb structure 25 are made of a material that can generate heat when electricity is applied, specifically, a material having PTC characteristics. If necessary, the peripheral wall 21 may also be made of a material having PTC characteristics, like the partition walls 24. With this configuration, it is possible to directly heat the moisture absorption layer 26 by heat transfer from the heat-generating partition walls 24 (and the peripheral wall 21, if necessary). Furthermore, a material having PTC characteristics has the property that, when the temperature rises and exceeds the Curie point, the resistance value rises rapidly, making it difficult for electricity to flow. Therefore, when the partition walls 24 (and the peripheral wall 21, if necessary) become hot, the current flowing through them is limited, thereby suppressing excessive heat generation in the honeycomb structure 25. Therefore, it is also possible to suppress thermal deterioration of the moisture absorption layer 26 caused by excessive heat generation.

[0049] From the viewpoint of obtaining appropriate heat generation, the lower limit of the volume resistivity at 25°C of a 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. From the viewpoint of generating heat at a low driving voltage, the upper limit of the volume resistivity at 25°C of a material having PTC characteristics 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 at 25°C of a material having PTC characteristics is measured in accordance with JIS K6271:2008.

[0050] From the viewpoint of being able to generate heat when electrically applied and having PTC characteristics, the outer peripheral wall 21 and the partition walls 24 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.

[0051] 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 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%. The content of these BaTiO3-based crystal particles can be measured by fluorescent X-ray analysis. Other crystal particles can also be measured in the same manner.

[0052] From the viewpoint of reducing the environmental load, it is desirable that the materials used for the outer peripheral wall 21 and the partition wall 24 are substantially free of lead (Pb). Specifically, the Pb content of the outer peripheral wall 21 and the partition wall 24 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 24 during heat generation to be safely applied to living organisms such as humans. The Pb content of the outer peripheral wall 21 and the partition wall 24, 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).

[0053] The Curie points of the materials constituting the outer peripheral wall 21 and the partition walls 24 are preferably in the temperature range at which the resistance value becomes at least twice the resistance 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 20 becomes hot, so that excessive heat generation in the humidity control device 20 is efficiently suppressed. Therefore, thermal degradation of the moisture absorbing layer 26 caused by excessive heat generation can be suppressed. The lower limit of the Curie point of the material constituting the outer peripheral wall 21 and the partition walls 24 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 26. 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.

[0054] The Curie point of the material forming the outer peripheral wall 21 and the partition walls 24 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.

[0055] 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), and the change in the sample's electrical resistance with respect to temperature change when the temperature is raised from 10°C is measured using a DC resistance meter (e.g., multimeter 3478A, manufactured by YOKOGAWA HEWLETT PACKARD, LTD.). The Curie point is determined as the temperature at which the resistance value is twice the resistance value at room temperature (20°C) based on the electrical resistance-temperature plot obtained by the measurement.

[0056] (2-2. Pair of electrodes 27a, 27b) 2A, the pair of electrodes 27a, 27b may be provided on the first end face 22a and the second end face 22b. Alternatively, the pair of electrodes 27a, 27b may be provided on the outer peripheral wall 21 parallel to the extension direction of the cells 23. By applying a voltage between the pair of electrodes 27a and 27b, it becomes possible to cause the honeycomb structure 25 to generate heat by Joule heat.

[0057] 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. Alternatively, an ohmic electrode capable of making ohmic contact with the outer peripheral wall 21 and / or the partition wall 24 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 27a, 27b may have a single-layer structure or a stacked structure of two or more layers. When the pair of electrodes 27a, 27b has a stacked structure of two or more layers, the materials of the layers may be the same or different.

[0058] The thickness of the pair of electrodes 27a, 27b can be set appropriately depending on the method for forming the pair of electrodes 27a, 27b. Examples of methods 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 also be formed by joining metal or alloy plates.

[0059] 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. Furthermore, when joining metal or alloy plates, the thickness is preferably about 5 to 100 μm.

[0060] (2-3. Terminal 28) Terminal 28 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 28 makes it easy to connect to an external power source. Terminal 28 is connected to a conductor that is connected to power source 50.

[0061] The material of terminal 28 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.

[0062] The size and shape of the terminal 28 are not particularly limited. For example, as shown in Fig. 2A, the terminal 28 may be provided on the entire pair of electrodes 27a, 27b on the outer peripheral wall 21. The terminal 28 may also be provided on a portion of the pair of electrodes 27a, 27b on the outer peripheral wall 21, or may be provided so as to extend outward beyond the outer edges of the pair of electrodes 27a, 27b on the outer peripheral wall 21. The terminal 28 may also be provided on a portion of the pair of electrodes 27a, 27b on the partition wall 24, or may be provided so as to cover some of the cells 23. The thickness of the terminal 28 is not particularly limited, but is, for example, 0.01 to 10 mm, typically 0.05 to 5 mm.

[0063] The method of connecting the terminal 28 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.

[0064] (2-4. Moisture absorption layer 26) The moisture absorbing layer 26 can be provided on the surface of the partition wall 24 (in the case of the outermost cell 23, the partition wall 24 and the outer wall 21 that define the outermost cell 23). By providing the moisture absorbing layer 26 in this manner, the moisture absorbing layer 26 can be easily heated during the regeneration process, and the moisture absorbing function of the moisture absorbing layer 26 can be regenerated.

[0065] The moisture absorbing layer 26 contains a moisture absorbing material. The moisture absorbent preferably has the function of adsorbing moisture (water vapor) at temperatures between −20 and 40° C. and desorbing it at temperatures as high as 60° C. or higher. Examples of moisture absorbents having such a function include aluminosilicate, silica gel, silica, graphene oxide, polymeric moisture absorbents, polystyrene sulfonic acid, and metal organic frameworks (MOFs). These may be used alone or in combination of two or more.

[0066] 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.

[0067] As the silica gel, it is preferable to use type A silica gel. The polymer moisture absorbent is preferably one having a polyacrylic acid polymer chain, such as 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).

[0068] The moisture absorption layer 26 may contain a functional material other than the moisture absorbent material or a catalyst. The functional material other than the moisture absorbent material is not particularly limited as long as it can exhibit the desired function, and an adsorbent or the like may be used. The adsorbent preferably has the function of adsorbing at least one selected from carbon dioxide and volatile components. The moisture absorption layer 26 containing such an adsorbent is capable of adsorbing carbon dioxide and / or volatile components in addition to moisture. Furthermore, the components to be removed can be purified by using a catalyst. Furthermore, the adsorbent and the catalyst may be used in combination to enhance the ability of the adsorbent to capture the components to be removed.

[0069] Adsorbents include zeolites, silica gel, activated carbon, alumina, silica, low-crystalline clay, and amorphous aluminum silicate complexes. Some of these components may also function as moisture absorbents. Adsorbents may be used singly or in combination.

[0070] The catalyst preferably has a function capable of promoting the oxidation-reduction reaction. Examples of catalysts having such a function 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.

[0071] 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.

[0072] The thickness of the moisture absorbing layer 26 is not particularly limited and may be determined depending on the size of the cells 23. For example, from the viewpoint of ensuring sufficient contact with air, the thickness of the moisture absorbing layer 26 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 26 from peeling off from the partition walls 24 and the outer peripheral wall 21, the thickness of the moisture absorbing layer 26 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 26 is measured by the following procedure. An arbitrary cross section parallel to the flow path direction of the honeycomb structure 25 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 taken so as to pass through the center of gravity of the cross section perpendicular to the flow path of the honeycomb structure 25. For each moisture absorption layer 26 visible in the cross-sectional image, the thickness is calculated by dividing the cross-sectional area by the length of the cell 23 in the flow path direction. This calculation is performed for all moisture absorption layers 26 visible in the cross-sectional image, and the overall average value is taken as the thickness of the moisture absorption layer 26.

[0074] From the viewpoint of enabling the moisture absorbent material or the like to exhibit the desired function within the humidity control device 20, the amount of the moisture absorbent layer 26 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 25. The volume of the honeycomb structure 25 is a value determined by the outer dimensions of the honeycomb structure 25.

[0075] (2-5. Manufacturing Method of Humidity Control Device 20) The method for producing the humidity control device 20 is not particularly limited and can be carried out in accordance with a known method. The method for producing the humidity control device 20 will be exemplified below. The method for manufacturing the honeycomb structure 25 that constitutes the humidity control device 20 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 the amount is such that the relative density of the honeycomb formed body is 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 actual 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 25 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 25 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 25 .

[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 25 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 27a, 27b are formed on the honeycomb structure 25 obtained in this manner. 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, or may be formed of multiple electrode layers with different compositions. Below, a typical method for forming the pair of electrodes 27a, 27b will be described.

[0089] First, an electrode slurry containing an electrode material, an organic binder, and a dispersion medium is prepared and applied to the first end surface 22a or the second end surface 22b of the honeycomb structure 25. 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 25 is removed by blowing and wiping. Thereafter, the slurry is dried to form a pair of electrodes 27a, 27b on the first end surface 22a or the second end surface 22b of the honeycomb structure 25. Drying can be performed while heating the heater element 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 27a, 27b of a desired thickness can be provided.

[0090] Next, when providing terminals 28, terminals 28 are placed at predetermined positions of the pair of electrodes 27a, 27b, and the pair of electrodes 27a, 27b are connected to terminals 28. The method described above can be used to connect the pair of electrodes 27a, 27b to terminals 28. The terminal 28 may be installed after the moisture absorbing layer 26 described below is formed.

[0091] Next, the moisture absorbing layer 26 is formed on the surfaces of the partition walls 24 and the like of the honeycomb structure 25 . The method for forming the moisture absorption layer 26 is not particularly limited, and it can be formed, for example, by the following process. The honeycomb structure 25 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 25 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 26 on the surface of the partition wall 24. The drying can be performed while heating the honeycomb structure 25 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 26 of a desired thickness can be provided on the surface of the partition wall 24 or the like.

[0092] (3. Heat Pump Cycle 30) The heat pump cycle 30 includes a condenser 31 disposed in the air conditioning duct downstream of the humidity control device 20. In particular, the condenser 31 is disposed in the inlet path 11 of the air conditioning duct . Condenser 31 can exchange heat between the heat of the refrigerant and the air. Specifically, condenser 31 can dissipate heat using the high-temperature, high-pressure refrigerant flowing inside, and heats the air passing around condenser 31.

[0093] The heat pump cycle 30 may further include an evaporator 32 disposed in the air conditioning duct 10 downstream of the humidity control device 20. In particular, the evaporator 32 is disposed in the inlet path 11 of the air conditioning duct 10. The evaporator 32 can exchange heat between the cold of the refrigerant and the air. Specifically, the evaporator 32 can absorb heat using the low-temperature, low-pressure refrigerant flowing inside, and cools the air passing around the evaporator 32.

[0094] The heat pump cycle 30 may further include a compressor 33, an outdoor heat exchanger 34, expansion valves 35a and 35b, and shutoff valves 36a to 36e, and these components are connected via a refrigerant flow path (refrigerant piping).

[0095] Compressor 33 has the function of compressing and discharging the refrigerant. The suction part of compressor 33 is connected to outdoor heat exchanger 34, and the discharge part is connected to condenser 31 via a refrigerant flow path. Compressor 33 is driven by control unit 40, and compresses the refrigerant to discharge high-temperature, high-pressure refrigerant into condenser 31. A known device such as a gas-liquid separator may be provided between the compressor 33 and the outdoor heat exchanger .

[0096] The outdoor heat exchanger 34 has a function of exchanging heat between the heat of the refrigerant and the outside air. The outdoor heat exchanger 34 can absorb heat from the outside air using the low-temperature, low-pressure refrigerant circulating inside, mainly during the heating operation mode, and vaporizes the refrigerant by absorbing heat from the outside air. Furthermore, the outdoor heat exchanger 34 can release heat to the outside air using the high-temperature, high-pressure refrigerant circulating inside, mainly during the cooling operation mode, and cools the refrigerant by releasing heat to the outside air.

[0097] The expansion valves 35a and 35b are throttle valves whose opening degrees can be adjusted by the control unit 40. In particular, when the heating operation mode is being performed, the expansion valve 35a reduces the pressure of the refrigerant discharged from the condenser 31 to expand it, and then discharges the low-temperature, low-pressure refrigerant to the outdoor heat exchanger 34. In addition, when the cooling operation mode is being performed, the expansion valve 35b reduces the pressure of the refrigerant from the outdoor heat exchanger 34 to expand it, and then discharges the low-temperature, low-pressure refrigerant to the evaporator 32.

[0098] The shutoff valves 36a to 36e are provided to control the flow path of the refrigerant. The control unit 40 controls the opening and closing of the shutoff valves 36a to 36e.

[0099] (4. Control unit 40) The control unit 40 controls the humidity control device 20 and the heat pump cycle 30 according to the operation mode. Therefore, the control unit 40 is electrically connected to the humidity control device 20 and the heat pump cycle 30. Specifically, the control unit 40 is connected to a power source 50 for applying a voltage to a pair of electrodes 27a, 27b of the humidity control device 20, and can adjust the heating state of the honeycomb structure 25 by controlling the power source 50. Furthermore, the control unit 40 is electrically connected to the shutoff valves 36a to 36e of the heat pump cycle 30, and can control the flow path of the refrigerant by opening and closing the shutoff valves 36a to 36e. Furthermore, the control unit 40 is electrically connected to the expansion valves 35a and 35b of the heat pump cycle 30, and can control the degree of decompression of the refrigerant by adjusting the opening degrees of the expansion valves 35a and 35b.

[0100] The control unit 40 is electrically connected to the valve 13, the ventilator 60, the air mix door 70, and the like in addition to the humidity control device 20 and the heat pump cycle 30, and can control these as well.

[0101] 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.

[0102] (5.Power supply 50) The power supply 50 is for applying a voltage to the pair of electrodes 27a, 27b. The power supply 50 is electrically connected to the control unit 40, and adjusts the state of voltage application to the pair of electrodes 27a, 27b in accordance with instructions from the control unit 40. The power source 50 is not particularly limited, and a battery or the like can be used.

[0103] (6. Ventilator 60) The ventilator 60 is provided to circulate air through the air conditioning duct 10. There are no particular limitations on the ventilator 60, and any known ventilator can be used. The position of the ventilator 60 is not particularly limited, and for example, it can be provided upstream of the humidity control device 20. However, the ventilator 60 may also be provided downstream of the condenser 31.

[0104] (7. Air Mix Door 70) Air mix door 70 is configured to rotate between a heating position in air conditioning duct 10, where it opens a heating path leading to condenser 31, and a cooling position, where it opens a cooling path that bypasses condenser 31. By rotating air mix door 70 between the heating position and the cooling position, it is possible to adjust the ratio of air passing through condenser 31 and air bypassing condenser 31, thereby adjusting the temperature of air flowing into the vehicle cabin.

[0105] In the vehicle air conditioning system according to the embodiment of the present invention, the operation modes of the humidity control device 20 include a warm-up mode in which air is heated by the humidity control device 20. The operation modes of the humidity control device 20 can further include a dehumidification mode and a regeneration mode. The operation mode of the humidity control device 20 can be selected in response to a switch operation by the driver or humidity changes detected by various detectors.

[0106] (A) Warm-up mode The warm-up mode is a mode that is executed in cold weather, such as when the temperature is below freezing. As shown in Fig. 1A, the warm-up mode is executed by controlling the valve 13 to allow air to flow into the inlet path 11 and by circulating air while applying a voltage to the humidity control device 20. By executing this warm-up mode, the humidity control device 20 can function as a substitute for a conventional PTC heater used as an auxiliary heat source, thereby improving heating efficiency and quick warm-up in cold weather. Since the humidity in the air is low in cold weather, the humidity in the vehicle cabin is unlikely to increase even if the humidity control device 20 operates in the warm-up mode when the heat pump cycle 30 starts operating in the heating mode.

[0107] The warming mode (heating of air by the humidity control device 20) is preferably performed within 10 minutes from the start of the heating operation mode of the heat pump cycle 30. By performing the warming mode during this period, it is possible to efficiently warm air in cold weather while reducing power consumption. From the viewpoint of stably ensuring this effect, the warming mode is preferably performed within 8 minutes, and more preferably within 5 minutes, from the start of the heating operation mode of the heat pump cycle 30.

[0108] The warming mode (heating of air by the humidity control device 20) is preferably stopped when the heating COP of the heat pump cycle 30 reaches a predetermined value of 1.0 or more. By stopping heating at this stage, it is possible to efficiently warm air in cold weather while reducing power consumption. Here, the heating COP is the energy consumption efficiency (coefficient of performance) of heating, and is an index that shows the energy-saving performance of heating. The heating COP can be calculated by dividing the heating capacity (kW) by the heating power consumption (kW). Furthermore, the stage at which the heating COP reaches a predetermined value of 1.0 or more means a stage at which the heating COP reaches a set value (for example, 1.1, 1.2, 1.3, etc.) of 1.0 or more. The set value of the heating COP of the heat pump cycle 30 at which heating is stopped is preferably 2.0 or less, and more preferably 1.5 or less, from the viewpoint of stably ensuring the above-mentioned effects.

[0109] (B) Dehumidification mode 1B and 1C, the dehumidification mode controls the valve 13 to allow air to flow into the inflow path 11, and dehumidifies the air by circulating the air through the humidity control device 20. By executing such a dehumidification mode, air from the vehicle interior or outside the vehicle can be quickly dehumidified. Note that, in FIG. 1A as well, the dehumidification mode is entered when no voltage is applied to the humidity control device 20.

[0110] (C) Playback mode 1D , the regeneration mode controls the valve 13 to allow air to flow out through the outlet path 12, and applies a voltage to the humidity control device 20 to heat it while circulating air, thereby regenerating the moisture absorption layer 26. By executing such a regeneration mode, the moisture absorption layer 26 of the humidity control device 20 can be quickly regenerated.

[0111] In the vehicle air conditioning system according to the embodiment of the present invention, the operation modes of the heat pump cycle 30 can include a heating operation mode and a cooling operation mode. The operation mode of the heat pump cycle 30 can be selected in response to a switch operation by the driver or temperature changes detected by various detectors.

[0112] (A) Heating operation mode 1A, in the heating operation mode, shutoff valves 36a to 36c are opened and shutoff valves 36d to 36e are closed, thereby forming a flow path in which the refrigerant flows sequentially through compressor 33, condenser 31, expansion valve 35a, and outdoor heat exchanger 34. In FIG. 1A, the flow path through which the refrigerant flows in this heating operation mode is indicated by a thick line. The refrigerant compressed by the compressor 33 enters the condenser 31 as a high-temperature, high-pressure refrigerant, and dissipates heat by exchanging heat with the air circulating in the air conditioning duct 10. The refrigerant leaving the condenser 31 is decompressed and expanded by the expansion valve 35a, becoming a low-temperature, low-pressure refrigerant. After that, it exchanges heat with the outside air in the outdoor heat exchanger 34, absorbing heat, and returns to the compressor 33. When this heating operation mode is performed, the air circulating in the air conditioning duct 10 is heated by the condenser 31, and the heated air flows into the passenger compartment. The temperature of the air flowing into the passenger compartment can be adjusted by controlling the opening degree of the air mix door 70. This heating operation mode can be implemented when the operation mode of the humidity control device 20 is the warming mode or the dehumidification mode.

[0113] (B) First cooling operation mode 1B, in the first cooling operation mode, shutoff valves 36a, 36d, and 36e are opened and shutoff valves 36b and 36c are closed, thereby forming a flow path in which the refrigerant flows sequentially through compressor 33, outdoor heat exchanger 34, expansion valve 35b, and evaporator 32. In FIG. 1B, the flow path through which the refrigerant flows in this cooling operation mode is indicated by a thick line. The refrigerant compressed by the compressor 33 to a high temperature and pressure is cooled by exchanging heat with outside air in the outdoor heat exchanger 34 and releasing heat. The refrigerant leaving the outdoor heat exchanger 34 is reduced in pressure and expanded in the expansion valve 35b, becoming a low temperature, low pressure refrigerant, which then enters the evaporator 32 and absorbs heat by exchanging heat with the air circulating in the air conditioning duct 10. The refrigerant leaving the evaporator 32 returns to the compressor 33. When this cooling operation mode is performed, the air circulating in the air conditioning duct 10 is cooled by the evaporator 32, and the cooled air flows into the vehicle compartment. This cooling operation mode is particularly useful when it is desired to rapidly cool the vehicle compartment (strong cooling operation mode). This cooling operation mode can be implemented when the operation mode of the humidity control device 20 is the dehumidification mode.

[0114] (C) Second cooling operation mode 1C, in the second cooling operation mode, shutoff valves 36a, 36c, and 36e are opened and shutoff valves 36b and 36d are closed, thereby forming a flow path in which the refrigerant flows sequentially through compressor 33, condenser 31, expansion valve 35a, outdoor heat exchanger 34, expansion valve 35b, and evaporator 32. In FIG. 1C, the flow path through which the refrigerant flows in this cooling operation mode is indicated by a thick line. In the cooling operation mode, the refrigerant flow path further includes a condenser 31 and an expansion valve 35a downstream of the compressor 33. In the cooling operation mode, the cooling of the air by the evaporator 32 and the heating of the air by the condenser 31 can be adjusted by controlling the opening degree of the air mix door 70, so that the air temperature can be controlled to an optimum temperature. This cooling operation mode can be implemented when the operation mode of the humidity control device 20 is the dehumidification mode.

[0115] It is desirable that the humidity control device 20 be placed near the vehicle interior. Therefore, from the viewpoint of preventing electric shock, etc., it is preferable that the driving voltage of the humidity control device 20 is 60 V or less. The honeycomb structure 25 used in the humidity control device 20 has low electrical resistance at room temperature, so that the honeycomb structure 25 can be heated 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 25 is heated will be large, and therefore the conductor wires will need to be thicker.

[0116] <Method for controlling vehicle air conditioning system> The control method for a vehicle air conditioning system according to an embodiment of the present invention includes a warm-up mode in which, in a vehicle air conditioning system having the above configuration, air is heated by the humidity control device 20 at the start of the heating operation mode of the heat pump cycle 30. This configuration allows the humidity control device 20 to function as a substitute for a conventional PTC heater used as an auxiliary heat source, thereby improving heating efficiency and quick warm-up in cold weather.

[0117] It is preferable that the humidity control device 20 heats the air (in the warm-up mode) within 10 minutes from the start of the heating operation mode of the heat pump cycle 30. By executing the warm-up mode during this period, it is possible to efficiently heat the air in cold weather while reducing power consumption.

[0118] It is preferable that the heating of air by the humidity control device 20 (warming mode) be stopped when the heating COP of the heat pump cycle 30 reaches a predetermined value of 1.0 or more. By stopping the heating at this stage, it is possible to efficiently warm air in cold weather while reducing power consumption.

[0119] In the vehicle air conditioning system, it is preferable that an inlet path 11 for introducing air into the vehicle compartment and an outlet path 12 for discharging air to the outside of the vehicle are provided between the humidity control device 20 and the condenser 31, a valve 13 capable of switching the air flow is provided between the inlet path 11 and the outlet path 12, and the condenser 31 is disposed in the inlet path 11. With this configuration, it becomes easier to perform the warming mode, dehumidification mode, and regeneration mode by the humidity control device 20, and to perform the heating operation mode and the cooling operation mode by the heat pump cycle 30.

[0120] The warm-up mode of the humidity control device 20 is preferably performed by controlling the valve 13 to allow air to flow into the inflow path 11, and by circulating air while applying a voltage to the humidity control device 20. By controlling in this manner, it is possible to efficiently warm air in cold weather while reducing power consumption.

[0121] In the vehicle air conditioning system, it is preferable that the humidity control device 20 further includes at least one operation mode selected from a dehumidification mode in which the valve 13 is controlled to cause air to flow into the inlet path 11 and the air is circulated through the humidity control device 20 to perform dehumidification, and a regeneration mode in which the valve 13 is controlled to cause air to flow out into the outlet path 12 and the humidity control device 20 is heated while the air is circulated to regenerate the moisture absorption layer 26. With this configuration, the dehumidification mode and the regeneration mode can be easily achieved by the humidity control device 20.

[0122] In the vehicle air conditioning system, the heat pump cycle 30 preferably further includes a compressor 33 that compresses and discharges a refrigerant, and the heating operation mode of the heat pump cycle 30 preferably includes introducing the refrigerant discharged from the compressor 33 into the condenser 31 to heat air. With this configuration, the heating operation mode of the heat pump cycle 30 can be easily realized. [Explanation of symbols]

[0123] 10 Air conditioning ducts 11 Inflow route 12 Outflow route 13 Valve 20 Humidity Control Device 21 Outer wall 22a First end surface 22b Second end face 23 cells 24 Bulkhead 25 Honeycomb structure 26 Moisture absorption layer 27a, 27b Pair of electrodes 28 terminals 30 Heat pump cycle 31 Capacitor 32 Evaporator 33 Compressor 34 Outdoor heat exchanger 35a, 35b Expansion valve 36a~36e Shut-off valve 40 Control Unit 50 power supply 60 Ventilator 70 Air Mix Door

Claims

1. an air conditioning duct through which air can circulate; a humidity control device disposed in the air conditioning duct; a heat pump cycle including a condenser disposed in the air conditioning duct downstream of the humidity control device; a control unit that controls the humidity control device and the heat pump cycle according to an operation mode; Equipped with the humidity control device includes 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 flow paths extending from a first end face to a second end face, at least the partition walls being made of a material having PTC characteristics; and a moisture absorbing layer formed on a surface of the partition walls, The vehicle air conditioning system includes a warm-up mode in which the control unit heats the air using the humidity control device when a heating operation mode of the heat pump cycle starts.

2. The vehicle air conditioning system according to claim 1 , wherein the humidity control device heats the air within 10 minutes from the start of the heating operation mode of the heat pump cycle.

3. 3. The vehicle air conditioning system according to claim 1, wherein the humidity control device stops heating the air when a heating COP of the heat pump cycle reaches a predetermined value of 1.0 or more.

4. the air conditioning duct has, between the humidity control device and the condenser, an inflow path for introducing the air into the vehicle compartment and an outflow path for discharging the air to the outside of the vehicle, and a valve capable of switching the flow of the air is provided between the inflow path and the outflow path; 3. The vehicle air conditioning system according to claim 1, wherein the condenser is disposed in the inlet path.

5. 5. The vehicle air conditioning system according to claim 4, wherein the warm-up mode of the humidity control device is performed by controlling the valve to allow the air to flow into the inlet path and by circulating the air while applying a voltage to the humidity control device.

6. The humidity control device is a dehumidification mode in which the valve is controlled to allow the air to flow into the inflow path and the air is dehumidified by circulating the air through the humidity control device; and a regeneration mode in which the valve is controlled to allow the air to flow into the outflow path, and the humidity control device is heated while the air is circulated to regenerate the moisture absorption layer; 5. The vehicle air conditioning system of claim 4, further comprising at least one operating mode selected from the following:

7. The heat pump cycle further includes a compressor that compresses and discharges a refrigerant, 3. The vehicle air conditioning system according to claim 1, wherein the heating operation mode of the heat pump cycle includes introducing the refrigerant discharged from the compressor into the condenser to heat the air.

8. 3. The vehicle air conditioning system according to claim 1, 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.

9. 3. The vehicle air conditioning system according to claim 1, wherein the moisture absorption layer is capable of adsorbing carbon dioxide and / or volatile components in addition to moisture.

10. an air conditioning duct through which air can circulate; a humidity control device disposed in the air conditioning duct; a heat pump cycle including a condenser disposed in the air conditioning duct downstream of the humidity control device; Equipped with the humidity control device includes a honeycomb structure having an outer peripheral wall and partition walls disposed inside the outer peripheral wall to define a plurality of cells that serve as flow paths extending from a first end face to a second end face, at least the partition walls being made of a material having PTC characteristics; and a moisture absorption layer formed on a surface of the partition walls, A control method for a vehicle air conditioning system, comprising a warm-up mode in which the air is heated by the humidity control device at the start of a heating operation mode of the heat pump cycle.

11. The method for controlling a vehicle air conditioning system according to claim 10, wherein the humidity control device heats the air within 10 minutes from the start of the heating operation mode of the heat pump cycle.

12. 12. The method for controlling a vehicle air conditioning system according to claim 10, wherein heating of the air by the humidity control device is stopped when a heating COP of the heat pump cycle reaches a predetermined value of 1.0 or more.

13. the air conditioning duct has, between the humidity control device and the condenser, an inflow path for introducing the air into the vehicle compartment and an outflow path for discharging the air to the outside of the vehicle, and a valve capable of switching the flow of the air is provided between the inflow path and the outflow path; 12. The method for controlling a vehicle air conditioning system according to claim 10, wherein the condenser is disposed in the inflow path.

14. 14. The control method for a vehicle air conditioning system according to claim 13, wherein the warm-up mode of the humidity control device is performed by controlling the valve to allow the air to flow into the inlet path and by circulating the air while applying a voltage to the humidity control device.

15. The humidity control device is a dehumidification mode in which the valve is controlled to allow the air to flow into the inflow path and the air is dehumidified by circulating the air through the humidity control device; and a regeneration mode in which the valve is controlled to allow the air to flow into the outflow path, and the humidity control device is heated while the air is circulated to regenerate the moisture absorption layer; The method of claim 13, further comprising selecting at least one operating mode from the group consisting of:

16. The heat pump cycle further includes a compressor that compresses and discharges a refrigerant, 12. The method for controlling a vehicle air conditioning system according to claim 10, wherein the heating operation mode of the heat pump cycle includes introducing the refrigerant discharged from the compressor into the condenser to heat the air.

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