Methods for improving fuel efficiency of vehicles, and methods for paying remuneration for vehicles and fuel efficiency improvements

Abstract

To provide a method for improving fuel economy for a movable body.SOLUTION: A method for improving fuel economy for a movable body includes forming a heat-insulation applied film by applying a coating material with hollow beads having elasticity to an external surface of a roof part of the movable body sharing an energy system for operation of movement and air conditioning in order that a load on the air conditioning can be decreased to decrease an amount used of the energy when activating the movable body.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a method for improving the fuel efficiency of a moving body, a moving body, and a method for using the amount of improved fuel efficiency as a reward amount for implementation.

Background Art

[0002] In recent years, due to environmental problems and energy problems, energy-saving efforts have been made in various fields. Among them, heat insulation of the roofs and walls of buildings has been widely carried out as an energy-saving measure that can be done retrospectively. As one of such energy-saving technologies, heat-insulating coating can be mentioned.

[0003] On the other hand, the ex post facto energy saving for moving bodies such as automobiles usually only involves installing sunshades inside the vehicle and has not advanced compared to buildings. Also, regarding energy saving in the manufacturing stage of automobiles, it only goes as far as inserting heat-insulating glass such as door glass and heat-insulating materials inside the roof. These energy-saving measures are to prevent heat from entering the vehicle interior as much as possible, but in the midsummer sunlight, the effect is not sufficient, and the air conditioner is currently operating at full capacity.

[0004] In addition, since a moving body moves, there are limitations to installing things like eaves. Also, since the appearance design is often emphasized for moving bodies, almost no energy-saving measures that can affect the appearance are carried out. That is, there is no idea of realizing energy saving (fuel efficiency improvement) of a moving body by applying heat-insulating coating ex post facto to the moving body.

[0005] Here, as a specific example of heat-insulating coating, which is one of the energy-saving technologies, there is a coating-type heat-insulating material comprising sodium aluminosilicate glass, a pigment, a resin emulsion, a dispersant, and an adhesive, wherein the sodium aluminosilicate glass has a hollow bead structure, a particle size of 10 to 50 μm, and a content thereof is 10 to 20% by weight of the total weight of the heat-insulating material (Patent Document 1).

[0006] However, an insulating coating film consisting only of ceramic hollow particles as hollow beads has problems such as being prone to cracking.

[0007] In addition, in many moving objects such as automobiles, the weight reduction and thinning of the body are progressing for the purpose of energy saving and shock mitigation during collisions. For this reason, the body and the like are easily deformed for shock absorption. When the above-mentioned paint is applied to such a surface, cracks and the like are more likely to occur in the coating film, so there is a problem that it is not suitable for painting moving objects.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0009] The problem to be solved is to provide a method for improving the fuel efficiency of a moving object aiming at improving the fuel efficiency of a moving object, etc.

Means for Solving the Problems

[0010] The first invention is a method for improving the fuel efficiency of a moving object that makes the energy systems for moving and operating the air conditioner the same. The air conditioner is for the purpose of air conditioning the passenger space and has elasticity. The first Hollow beads each bead having a density level at which the first hollow bead and the second hollow bead, which is a material harder than the first hollow bead, come into contact with each other during coating film formation A paint containing is applied to the outer surface of the roof portion of the moving object to form a plurality of insulating coating films in stages to a predetermined film thickness, and the energy consumption is reduced by reducing the load of the air conditioner when the moving object is started. It is a method for improving the fuel efficiency of a moving object. The second invention is a method for improving the fuel efficiency of a moving object that makes the energy systems for moving and operating the air conditioner the same. It is made of a first hollow bead having elasticity and a material harder than the material of the first hollow bead. with a small ratio of the maximum particle size A method for improving the fuel efficiency of a moving body, which comprises applying a paint containing a coating film forming material having the same material as the second hollow beads and the first hollow beads to the outer surface of the roof portion of the moving body to form a heat insulating coating film, and reducing the amount of energy used by reducing the load on the air conditioner when the moving body is started. Further, a third invention is a method for improving the fuel efficiency of a moving body in which the energy systems for moving and operating the air conditioner are the same, and the air conditioner is for air conditioning the passenger space and has elasticity The first hollow beads each bead having a density level at which the first hollow bead and the second hollow bead, which is a material harder than the first hollow bead, come into contact with each other during coating film formation A method for improving the fuel efficiency of a moving body, which comprises applying a paint containing the same to a predetermined body surface before exterior decoration of the moving body, forming a plurality of heat insulating coating film layers step by step to a predetermined film thickness, and reducing the amount of energy used by reducing the load on the air conditioner when the moving body is started. Further, a fourth invention is a method for improving the fuel efficiency of a moving body in which the energy systems for moving and operating the air conditioner are the same, and the first hollow beads having elasticity and a material harder than the material of the first hollow beads with a small ratio of the maximum particle size A method for improving the fuel efficiency of a moving body, which comprises applying a paint containing a coating film forming material having the same material as the second hollow beads and the first hollow beads to a predetermined body surface before exterior decoration of the moving body, forming a heat insulating coating film layer, and reducing the amount of energy used by reducing the load on the air conditioner when the moving body is started. Further, a fifth invention is a moving body to which the method for improving the fuel efficiency of a moving body according to any one of the first to fourth inventions is applied.

Effect of the Invention

[0011] According to the present invention, by using a paint containing elastic hollow beads suitable for painting a moving body, a heat insulating coating film is formed on the outer surface of the roof portion of the moving body to reduce the influence of radiant heat and the like, thereby reducing the load on the air conditioner, and improving the fuel efficiency of the moving body in which the energy systems for air conditioning and operation are the same can be expected.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying out the Invention

[0013] Hereinafter, the present invention will be described in detail based on its embodiments.

[0014] <Terms> The moving body in the present invention means a vehicle that moves by an engine using gasoline, light oil, heavy oil, ethanol, etc. as fuel, or a motor using electric energy such as a secondary battery or a fuel cell, and has a function of operating air conditioning in the same energy system as them. Specifically, automobiles such as buses, trucks, and passenger cars equipped with air conditioning, trains, railway vehicles such as trains, airplanes, and ships can be cited as examples of the moving body.

[0015] The fuel consumption in the present invention means the moving distance with respect to the amount of consumed energy (in other words, the consumption amount of an energy source such as fuel). Therefore, the improvement of the fuel consumption of the moving body in the present invention means that the moving distance with respect to the amount of consumed energy becomes longer before and after the application of the fuel consumption improvement method according to the present invention.

[0016] The energy for movement and air conditioning in the present invention refers to the energy used for powering the running of a moving body and the energy used for the heat source of cooling and heating (such as the operation of a compressor for circulating a refrigerant and the operation of a heater for direct or indirect use of heat). Also, it may be not only the energy derived from conventional fuels such as gasoline and light oil, but also the energy derived from electricity or the like. And the moving body in the present invention may be any one that performs movement and air conditioning with energy from the same system. This means a moving body in which the energy systems of an internal combustion engine, an electric motor, etc. related to movement and the energy of a compressor related to air conditioning are partially connected (not a separated and independent system).

[0017] In a moving body with the same energy system for movement and air conditioning operation like this, in summer, due to the influence of radiant heat etc., the temperature inside the moving body rises, and in winter, the temperature inside the moving body drops due to radiative cooling, the air conditioning load increases, and as a result, problems such as a decrease in fuel efficiency occur. The present invention is directed to such a moving body.

[0018] The hollow beads in the present invention refer to particles having voids or spaces inside the beads, and they may be in any of a closed system where air is blocked inside and outside the beads, an open system where the inside and outside of the beads communicate such as a porous structure or a donut structure.

[0019] <Concept of the present invention> Figure 1 is a conceptual diagram of a moving body and a coating film according to the present invention. In Figure 1, a paint is applied to the outer surface of the roof portion 1a of the moving body 1 that contacts the outside air, and a heat-insulating coating film 2 is formed. The outer surface of the roof portion 1a is located above the air-conditioning area 3 and is a location where external factors such as radiant heat are likely to be transmitted to the air-conditioning area 3. By forming the heat-insulating coating film 2 at this portion, in summer, the temperature rise of the air-conditioning area 3 is suppressed (Figure 2).

[0020] Figure 2 is an enlarged conceptual diagram of the location where the coating film 2 is formed. A heat-insulating coating film 2 is formed on the outer surface of the roof portion 1a of the moving body 1. The coating film 2 is composed of a coating film forming material 4, soft elastic hollow beads 5, and hard hollow beads 6 (details will be described later). This coating film 2 reduces the influence of radiant heat 7 and suppresses the temperature rise in the air-conditioned area 3 inside the moving body 1. The coating film 2 may be formed not only on the outer surface of the roof portion 1a but also on the front, back, sides, etc. of the moving body 1. Also, in winter, the coating film 2 reduces the influence of radiative cooling and prevents heat from escaping from the air-conditioned area 3, suppressing the temperature drop in the air-conditioned area 3 inside the moving body 1.

[0021] <Moving body> The moving body 1 according to this embodiment is a gasoline vehicle. As shown in FIG. 1, the energy source (gasoline storage section), engine, and compressor of the automobile are connected as an energy system. In the case of a gasoline vehicle, gasoline is used for combustion to operate the engine, and the engine operates the air-conditioning compressor. For example, with an engine, which is an internal combustion engine, as the power source, the air-conditioning compressor operates. In this way, gasoline, which is the fuel, is used not only for movement but also for the air-conditioning inside the vehicle. A moving body having such an energy system is the object of the method according to the present invention. Also, the energy source does not necessarily have to be limited to one, and may be used in combination, or the energy may be wholly or partially converted (for example, the power is converted to electricity). Also, as an example of making the energy systems for movement and air-conditioning operation the same, there is an example where the electric power generated by a generator connected to the engine is charged to a battery, and the air-conditioning compressor operates with the electric power from the generator or the battery.

[0022] Examples other than gasoline vehicles include electric vehicles, hydrogen vehicles, fuel cell vehicles, hybrid vehicles, etc. For example, in an electric vehicle, for movement, the electricity received from the battery is used as the power for movement, and for air conditioning, the electricity received from the battery is used as the power for the circulation of the refrigerant (energizing the heater in the case of heating by a PTC heater, and burning fossil fuel instead of electricity in the case of a combustion type heater). In this case, the moving body in which the electrical system used for air conditioning is connected to the electrical system used for movement is the object of the method according to the present invention. Also in hydrogen vehicles and fuel cell vehicles, the moving body in which the electricity obtained by the combustion of hydrogen or the chemical reaction between hydrogen and oxygen is used not only for movement but also for air conditioning is the object of the method according to the present invention. The same applies to hybrid vehicles. That is, not only the moving body in which the power or heat source used for air conditioning is gasoline combustion, but also the moving body in which the electricity obtained by power generation during running is used is the object of the method according to the present invention because the energy systems are connected. Thus, the moving body in which the energy source, the power conversion mechanism related to movement (such as an engine), and the power conversion mechanism related to air conditioning (such as a compressor) or the heat source are connected as an energy system is the object of the method according to the present invention.

[0023] <Paint> Figure 3 is an enlarged image of the coating film 2 posted with the paint according to the present embodiment. Figure 3 shows a state in which soft hollow beads 5 having elasticity and hard hollow beads 6 are mixed and adjacent to each other. There may be multiple types of hollow beads.

[0024] Examples of the coating film forming material 4 include acrylic emulsion resin. The coating film forming material 4 may be a resin coating film forming material mainly composed of urethane-based, silicon-based, or fluorine-based components other than acrylic.

[0025] Examples of the material of the soft hollow beads 5 having elasticity include plastics such as acrylic, polystyrene, and polycarbonate, and elastomers such as rubber. The soft hollow beads 5 are preferably made of the same material as the coating film forming material 4. For example, when the coating film forming material 3 is acrylic emulsion resin, they are acrylic hollow beads.

[0026] The hard hollow beads 6 are, for example, ceramic hollow beads or glass hollow beads. Examples of the ceramic hollow beads include those made from volcanic ash with 65 to 73% silicon dioxide and 12 to 18% aluminum oxide as the main components.

[0027] The ratio of the soft hollow beads 5 to the hard hollow beads 6 is preferably 1:1 or in the vicinity thereof on a weight basis or a volume basis. When the ratio of the soft hollow beads 5 is high, the flexibility of the coating film becomes high when the paint dries, but the thickness of the coating film obtained by a single application is not sufficient. That is, it is necessary to increase the number of coating applications. On the other hand, when the ratio of the hard hollow beads 6 is high, the thickness of the coating film obtained by a single application becomes thick when the paint dries, but the flexibility of the coating film is impaired. Considering the passage of time, the ratio of the soft hollow beads 2 is preferably 50% or more on a volume basis or a weight basis.

[0028] Using a plurality of materials with different properties in this way is to make use of the bead characteristics (heat insulation effect, molding effect, sound insulation effect, durability performance, etc. obtained from the shape and composition) of each material. In the following examples, the hollow beads are acrylic hollow beads and ceramic hollow beads in a 1:1 ratio on a weight basis.

[0029] The particle size of the hollow beads such as the soft hollow beads 5 and the hard hollow beads 6 preferably has a predetermined width (for example, a width from a particle size of 80 μm to 50 μm) as the particle size difference based on the maximum particle size. By having a width in the particle size distribution, when a solvent such as water volatilizes from the paint and a paint film is formed, the small particle size hollow beads enter between the hollow beads with the maximum particle size, making the hollow beads denser. The maximum particle size of the hollow beads may be defined by the coarseness of the mesh of the filter used for filtering the hollow beads, the mesh size, etc.

[0030] The hollow beads consist of a lineup of three particle sizes (particle size lineup) in any component. Here, the particle size lineup means that the particle sizes of the hollow beads are configured into a plurality of intended particle sizes. In this example, the particle sizes of the hollow beads of each material have peaks in the hollow ratio (the ratio of the total volume of the hollow parts for each particle size occupying in the coating film) at particle sizes of 80 μm, 60 μm, and 50 μm, and the weight ratio is 5:3:2 (including the fine beads generated during the manufacturing process).

[0031] In this example, the 80-μm hollow beads are the largest in both volume and weight. Also, the film thickness of the hollow beads of each particle size is about 1 μm to several μm, and generally, the volume of the hollow part inside the beads is 80% or more of the beads.

[0032] There are various methods for confirming the particle size distribution of the hollow beads. For example, there is a method of measuring the corresponding particle size from the area of the hollow beads in the enlarged image of FIG. 3. Also, there are the Coulter method of measuring the volume of individual particles and measuring the corresponding particle size, and other so-called centrifugal sedimentation method, laser diffraction / scattering method, etc. Since the hollow beads are very fine, it is technically difficult to manufacture hollow beads with accurate particle sizes. Therefore, the particle size distribution should be confirmed on the premise of manufacturing errors. For example, there is a method in which hollow beads with particle sizes in the range of 80 μm ± 5 μm are counted as 80-μm particle size hollow beads.

[0033] Also, the shape of the hollow beads such as the soft hollow beads 5 and the hard hollow beads 6 is preferably spherical as shown in FIG. 3, but it does not have to be spherical. When the hollow beads are not spherical and have a distorted shape like fragments, the particle size may be the average of the maximum width and the minimum width of the hollow beads, the maximum width of the hollow beads, or the minimum width of the hollow beads.

[0034] <Coating agent> Methanol (90% by weight or more), water (4% by weight or more), tin oxide (SnO 2)(0.1% by weight) of the mixture is the main coating agent. The coating agent may be a hydrophilic coat described in Japanese Patent Application Laid-Open No. 2019-002671 or the like, or something similar. However, it is not necessarily required.

[0035] The coating agent may contain components for purposes other than heat insulation, such as photocatalysts like titanium oxide, zinc oxide, tin oxide, etc. In this case, the coating film has a multi-functional structure with a lower layer for heat insulation and an upper layer with another function. For example, photocatalysts such as titanium oxide in the coating agent clean the painted surface through its hydrophilicity and photocatalytic reaction.

[0036] (Example 1) The formation of the coating film and the evaluation of the heat insulation effect of the method according to the present invention will be described below. In this example, the automobiles (passenger cars and buses) of a transportation company are the evaluation objects.

[0037] The coating process consists of a step of removing dirt on the surface of the target equipment by high-pressure water washing and a step of making the paint film thickness about 300 - 400 μm (when dry) with a roller brush. The coating method is not limited. For example, spraying can be mentioned. By the above roller brush, a film thickness of about 200 μm (when dry) was formed in the first coating and about 400 μm (when dry) in the second coating. The state of this film thickness hardly changed even after one year.

[0038] Figure 4 shows the state where the coating film 2 is formed on the roof part (omitted for buses). The part surrounded by the dotted line is the formation part of the coating film 2. The coating film 2 was confirmed to have a predetermined thickness on both the horizontal plane and the inclined plane of the roof in any automobile. Also, no abnormalities such as cracks or breaks in the coating film were observed in the driving tests under various driving conditions (various weather conditions, road conditions, moving speeds).

[0039] Figure 5 shows the exterior of a car after painting (left) and the infrared thermography of the car (right). These figures are for a car left outdoors for a certain period of time. The temperature of the roof part where the heat-insulating coating film is formed is 35 - 40°C, while the hood part is 55 - 60°C. A temperature difference of about 20°C was confirmed between the coating film forming part and other parts. The same is true for buses. Also, the same tendency was observed for cars after driving.

[0040] Figure 6 shows the exterior of a car with and without painting (left (left is without painting, right is with painting)) and its thermography (right). These figures are also for a car left outdoors for a certain period of time. The temperatures of parts other than the roof part of the car were all about 50°C and were similar. On the other hand, the temperature of the roof part was about 50°C without painting, while it was 30 - 35°C with painting. Although the surface temperature varies depending on the observation conditions, a temperature difference of about 20°C was confirmed depending on whether there is painting or not. The same is true for buses. Also, the same tendency was observed for cars after driving.

[0041] The rate of increase in the interior temperature and the maximum temperature before and after painting, with or without painting, were all such that for all cars, no painting > with painting, before painting > after painting. That is, it was confirmed that the interior temperature of the car without painting and before painting increased rapidly compared to the car with painting and after painting, and its maximum temperature was also higher.

[0042] Also, due to the running of the car, etc., certain vibrations, etc. occur in the roof part. As a result, stress is generated in the coating film 2 formed on the outer surface of the roof part. Regarding this problem, no abnormalities were confirmed in the appearance and inside the film of the coating film 2 after driving.

[0043] (Example 2) The verification of the method according to the present invention will be described below.

[0044] The method according to the present invention has been confirmed to reduce the increase in temperature of the in-vehicle air-conditioned space. That is, painting the outer surface of the roof portion of a moving body can be expected to have an effect of improving fuel efficiency by a post-treatment (for example, after purchasing a car). This solves two problems in a moving body such as an automobile. The first is that the roof portion is affected by radiant heat, increasing the air-conditioning load of the air-conditioned space. The second is that the roof portion is unstable, making it difficult to form and maintain a coating film.

[0045] Regarding the first problem, in the case of parking, etc., a garage or awnings, etc. are effective, but there was no effective measure during driving (especially during long-time driving on a sunny day with strong sunlight). It has been confirmed that the method according to the present invention can reduce the temperature rise of the air-conditioned space by 20°C or more. It is suggested that reducing the air-conditioning load suppresses the consumption of the power source related to air-conditioning and improves fuel efficiency.

[0046] The above suggestion has also been obtained from the air-conditioning power reduction test of a building. The air-conditioning power reduction test of a building is a confirmation test of how much the roof, etc. of a building insulated by the above paint can reduce the amount of air-conditioning power. In this test, a more precise evaluation is possible compared to an automobile test with many variable factors such as the number of passengers and driving conditions. The test result was an annual average power reduction of about 17% before and after using the paint.

[0047] Regarding the second problem, in recent years, the application of ceramic paint, which has been increasingly used, can be considered. However, it is known that hollow beads of hard materials such as ceramics often crack or break. In an environment where the roof portion vibrates during movement and stress is generated in the coating film, ceramic paint has a problem that cracking is more likely to occur when the density of the hollow beads is large, and the heat insulation property deteriorates when the density is small.

[0048] Almost no cracks were observed in the beads (ceramic hollow beads made of hard materials and acrylic hollow beads made of soft materials) in the paint according to the present invention. This is considered to be due to the elasticity of the acrylic hollow beads. That is, a paint containing hollow beads having elasticity and harder hollow beads than these can be expected to form a coating film on an unstable member. Thus, it was suggested that a paint in which a material capable of withstanding the stress of the hollow beads of one material is selected enables both the formation and maintenance of a desired film thickness on the roof portion.

[0049] In addition, although the paint is applied to the outer surface of the roof portion after the exterior decoration in this embodiment, it was suggested that it can also be applied to the body surface of the moving body 1 such as the roof before the exterior decoration. By another evaluation different from this embodiment, it has been confirmed that a coating film can be formed on the body material of an automobile and other materials such as ceramics, metals, and plastics. Thus, it can be expected that a moving body with good fuel efficiency can be obtained as a finished product by painting the body member before the exterior decoration.

[0050] In addition, the fuel efficiency improvement method according to the present invention can be applied to a charging method for a moving body after being put on the market, such as a used car. Specifically, it is a method in which the amount corresponding to the improvement in fuel efficiency by applying the fuel efficiency improvement method according to the present invention is set as the implementation reward amount of the method. In the case of a gasoline vehicle, at least the difference in the amount of gasoline used (the difference in gasoline purchase costs) at a predetermined driving distance is used as the standard for the implementation reward amount. In addition, factors that indirectly affect fuel efficiency, such as the number of passengers and the temperature, can also be used as the standard for the implementation reward amount. Thus, it can be expected that the implementation reward amount corresponding to the improvement in fuel efficiency will lead to the service provision and spread of the method according to the present invention.

[0051] (Example 3) Verification of useful forms of the paint according to the present invention will be described below.

[0052] As described above, in the paint using only the hollow beads of the hard material as the hollow beads, although the formation of the coating film is easy, there are problems such as cracks and fractures in the coating film, so the hollow beads cannot be made dense. On the other hand, it was suggested that a combination of hollow beads of a hard material and hollow beads of a soft material, like the paint according to the present invention, can be made as dense as the beads contact each other.

[0053] Here, there is Young's modulus as an index of the elasticity of the material. The Young's modulus of synthetic resins is often 4 or less. It is said that the Young's modulus of glass is 80, and the Young's modulus of inorganic compounds such as silicon dioxide and aluminum oxide that form ceramics is 100 or more. Based on these common technical knowledges and the results of this example, it was suggested that at least a combination of a soft material with a Young's modulus of 4 or less and a hard material with a Young's modulus of 80 or more can form a dense hollow bead layer in the paint.

[0054] Also, in this example, the materials of both the coating film forming material and the soft hollow beads are acrylic resins. Such a selection of materials is greatly related to the strength of the coating film. In the case of a combination of an acrylic coating film forming material and a soft hollow bead made of a material softer than acrylic, the strength of the entire coating film further decreases. Therefore, it is necessary to make at least the materials of the coating film forming material and the soft hollow beads the same.

[0055] Furthermore, from these findings, it was suggested that a combination of an acrylic coating film forming material and hollow beads harder than acrylic increases the strength of the coating film. Thus, the soft hollow beads should not be softer than the material of the coating film forming material, but if they are hard, they do not have to be the same material as the coating film forming material. For example, when the material of the coating film forming material is acrylic, the material of the hollow beads can be urethane or silicon.

[0056] In addition, as the coating film forming material, it was confirmed that heat insulation effects can also be obtained with urethane-based, silicon-based, and fluorine-based materials in addition to acrylic-based materials. That is, it was suggested that all synthetic resins can be applied as the coating film forming material according to the present invention. However, acrylic is the most excellent among the coating film forming materials according to the present invention in terms of the formability of the coating film.

[0057] The usage amount of the hollow beads varies depending on the thickness of the coating film and the particle size of the beads. Also, the density level of the hollow beads shown in FIG. 3 serves as a guide for forming a desired film thickness.

[0058] In this example, the particle sizes of the hollow beads of each material are 80 μm, 60 μm, and 50 μm, and the weight ratio is 5:3:2. As shown in FIG. 3, the proportion of the hollow beads with the largest particle size is also the largest in terms of volume ratio. Thus, the finding that the maximum heat insulation effect is obtained when the volume ratio of the hollow beads with the largest particle size is the largest has been obtained.

[0059] In this example, mainly hollow beads with a maximum particle size of 80 μm and a minimum particle size of 50 μm (particle size difference of 30 μm) were used. Empirically, the maximum particle size is preferably in the range of 50 to 100 μm. The minimum particle size is not limited and may be less than 1 μm because it can contribute to increasing the density of the hollow beads.

[0060] In addition, the particle size lineup enables a dense structure of the hollow beads, thereby increasing the heat insulation effect. The same applies to a combination of hollow beads having two or more peaks in the particle size distribution. Such peaks may be 60 μm, 50 μm, or even smaller. For example, those with a particle size that can fill the gaps between adjacent hollow beads with the largest particle size may be used. Theoretically, such hollow beads can maximize the dense state of the hollow beads.

[0061] In addition, in this embodiment, hollow beads mainly in the range of 80 μm to 50 μm were used. From this, it is suggested that a configuration of hollow beads with a particle size difference of at least 30 μm is useful. The particle size is not limited, and for example, a configuration of hollow beads with a maximum particle size of 100 μm and a minimum particle size of 70 μm can be mentioned. Also, a configuration of hollow beads with a minimum particle size of less than 1 μm to hollow beads with a particle size of 30 μm or more may be used.

[0062] In addition, it is suggested that at the maximum particle size (for example, 80 μm), the proportion of ceramic hollow beads is large, and at particle sizes smaller than that (for example, 60 μm and 50 μm), the proportion of acrylic hollow beads is large, which is useful for film thickness formation. When the beads with the maximum particle size are ceramic, the acrylic hollow beads may have a particle size that can separate the ceramic hollow beads so that they do not contact each other.

[0063] Also, it is suggested that the larger the proportion of acrylic hollow beads with the maximum particle size, the more useful it is for heat insulation. That is, the hollow beads with the maximum particle size are acrylic hollow beads, and the beads with a particle size that fills the gaps between these acrylic hollow beads may be ceramic hollow beads. Furthermore, urethane hollow beads or silicon hollow beads harder than acrylic hollow beads can be cited as examples of alternatives to acrylic hollow beads. These materials may be able to maintain the formation of the coating film even with a small amount of ceramic hollow beads used. Thus, any configuration of particle size and material that can maintain the formability of the coating film and avoid adverse effects such as cracking due to contact between the hollow beads is acceptable.

[0064] In addition, the film thickness of the paint changes due to various factors. For example, the film thickness is smaller after the paint dries than immediately after painting. This is because water and the like in the paint volatilize. Also, the film thickness expands and contracts due to the influence of temperature, humidity, etc. Therefore, it is assumed that when the coating film shrinks, the adjacent hard hollow beads deform the soft hollow beads into a concave shape. It is important to select a material that can maintain the hollow structure of the beads while withstanding the stress related to such coating film shrinkage.

[0065] For the formation of the desired film thickness, the material selection of the coating film forming material is also important. The formability of the coating film improves (or deteriorates) depending on the combination of the material of the coating film forming material and the material of the soft hollow beads. At least, it is important for the formability of the coating film that the material of the coating film forming material and the material of the soft hollow beads are the same. Thus, the selection of the three materials, namely, the coating film forming material, the soft hollow beads, and the hard hollow beads (furthermore, the particle size of the hollow beads) affects the properties of the coating film. From this example, it is suggested that a coating material having desired characteristics can be obtained based on these factors.

[0066] As an example, in this example, a coating film of about 400 μm formed on the outer surface of the roof portion maintained its state and exhibited a heat insulation effect. It is also possible to realize those with a higher filling amount of hollow beads and those with a film thickness exceeding 400 μm (600 μm, 800 μm, or a film thickness greater than that).

[0067] (Example 4) Other applications of the method according to the present invention will be described below.

[0068] Another application is sound insulation. According to the sensory evaluation of the influence of the film thickness of the coating material according to the present invention and the external sound heard by the evaluator (low-frequency sound from machines, rain sound, etc.), it is known that the external sound can be greatly reduced when the film thickness is 400 μm or more. It is suggested that the sound insulation in the air-conditioning area is enhanced by applying the coating material according to the present invention to the surface of the member of the moving body surrounding the air-conditioning area of the moving body to form a coating film with a desired film thickness. This may be realized together with the fuel efficiency improvement effect, or may be realized only for sound insulation for a moving body in which the energy systems for movement and air-conditioning operation are different.

[0069] In addition, as another application, prevention of heat stroke can be mentioned. Similar to the sound insulation effect, the effect increases as the film thickness of the paint increases, and it is known that it can prevent the temperature in the air-conditioned area from rising due to radiant heat or the like to a certain extent. Prevention of heat stroke is considered as one of the inherent effects of heat-insulating paint. However, as a characteristic of the paint according to the present invention, the ability to form a coating film with a desired film thickness on a surface that is easily bent like a roof part may greatly exceed the effect of general heat-insulating paint. In addition, it is expected that the temperature rise (temperature gradient and maximum temperature) in the air-conditioned area due to radiant heat or the like will vary depending on the material, thickness, surface treatment, etc. of the members constituting the moving body. Then, for example, for a moving body with a steep temperature gradient in the air-conditioned area, it is suggested that by increasing the film thickness (to a film thickness of 400 μm or more, such as 600 μm or 800 μm), measures for preventing heat stroke can be taken according to the characteristics of the moving body, such as moderating the temperature rise. This may be realized together with the fuel efficiency improvement effect, or only the heat stroke prevention measures may be realized for a moving body in which the energy systems for movement and air-conditioning operation are different.

Industrial Applicability

[0070] The present invention can be used to improve fuel efficiency by heat insulation of various moving bodies such as automobiles, railway vehicles, ships, airplanes, etc. In addition, it can also be used for sound insulation of moving bodies by the dense hollow beads in the heat-insulating coating film. Further, the present invention can be used to prevent the air-conditioned area of a moving body from getting hot in summer and to prevent heat stroke of the people inside.

Explanation of Symbols

[0071] 1 Moving body 2 Coating film 3 Air-conditioned area 4 Coating film forming material 5 Soft hollow beads 6 Hard hollow beads

Claims

1. A method for improving fuel efficiency of a mobile body that shares the same energy system for movement and air conditioning operation, the air conditioning being intended to provide air conditioning for the passenger space, the method comprising: applying paint containing first hollow beads having elasticity and second hollow beads made of a material harder than the first hollow beads at a density level at which the first hollow beads and second hollow beads having a density level at which the first hollow beads come into contact with each other when a coating film is formed to an outer surface of a roof portion of the mobile body, forming an insulating coating film in multiple layers in stages to a predetermined film thickness, and reducing the load on the air conditioning when the mobile body is started, thereby reducing the amount of energy used.

2. A method for improving fuel efficiency of a mobile body that uses the same energy system for movement and air conditioning operation, comprising applying a paint containing first hollow beads having elasticity, second hollow beads made of a material harder than the material of the first hollow beads and having a smaller maximum particle size ratio, and a coating film forming material made of the same material as the first hollow beads to the outer surface of a roof portion of the mobile body to form an insulating coating film, thereby reducing the load on the air conditioning when the mobile body is started, thereby reducing the amount of energy used.

3. A method for improving fuel efficiency of a mobile body that uses the same energy system for movement and air conditioning operation, the air conditioning being intended to provide air conditioning for a passenger space, the method comprising: applying paint containing first hollow beads having elasticity and second hollow beads made of a material harder than the first hollow beads at a density level at which the first hollow beads come into contact with each other when a paint film is formed to a specified body surface of the mobile body before the exterior decoration, forming a plurality of insulating paint layers in stages to a specified film thickness, and reducing the load on the air conditioning when the mobile body is started, thereby reducing the amount of energy used.

4. A method for improving fuel efficiency of a mobile body that uses the same energy system for movement and air conditioning operation, comprising applying a paint containing first hollow beads having elasticity, second hollow beads made of a harder material than the material of the first hollow beads and having a smaller maximum particle size ratio, and a coating film forming material made of the same material as the first hollow beads to a specified body surface of the mobile body before the exterior decoration, thereby forming an insulating coating film layer, thereby reducing the load on the air conditioning when the mobile body is started, thereby reducing the amount of energy used.

5. A moving body to which the method for improving fuel efficiency of a moving body according to any one of claims 1 to 4 is applied.

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