JP2009043470A - Electric heater, exhaust system, internal combustion engine, fuel cell system, heating system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve energy efficiency of an electric heater. <P>SOLUTION: The resistance value of a region 6a of a wave-form thin plate 6 which does not contact a flat thin plate 5 is made higher than that of a region 6b of the wave-form thin plate 6 in contact with the flat thin plate 5, thereby, temperature rising efficiency of the region 6a becomes higher than the temperature rising efficiency of the region 6b. Thus, the energy efficiency of the whole electric heater can be made higher. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electric heater suitable for application to an exhaust system of various systems.

2. Description of the Related Art Conventionally, an electric heater formed by continuously winding a strip-like flat thin plate and a corrugated thin plate around a central electrode is known. Among such electric heaters, there is one in which a large number of holes are formed over the entire surface of a flat thin plate and a corrugated thin plate (see Patent Document 1).
Japanese Patent Laying-Open No. 2005-224716 (see, for example, paragraph [0015])

  Since a hole is formed in a portion where the flat thin plate and the corrugated thin plate are in contact with each other, a partial heat capacity at a contact portion between the flat thin plate and the corrugated thin plate is increased, and a portion having a low temperature rising efficiency is formed. For this reason, according to the conventional electric heating element, it is difficult to efficiently raise the temperature of the flat thin plate and the wave thin plate, and it is difficult to improve energy efficiency (temperature increase rate per unit mass / power consumption amount). there were.

  This invention is made | formed in order to solve such a subject, The objective is to provide the electrical heating body with high energy efficiency. Another object of the present invention is to provide an energy efficient exhaust system. Still another object of the present invention is to provide an internal combustion engine having high energy efficiency. Still another object of the present invention is to provide a fuel cell system with high energy efficiency. Still another object of the present invention is to provide a heating system with high energy efficiency.

  The present invention is an electric heating element formed by continuously winding a flat thin plate and a wave thin plate around a center electrode, and at least one of the flat thin plate and the wave thin plate is not in contact with the other thin plate. The temperature rising efficiency of the region is higher than the temperature rising efficiency of the region in contact with the other thin plate.

  According to the present invention, since the temperature raising efficiency in the region not in contact with the other thin plate is higher than the temperature raising efficiency in the region in contact with the other thin plate, the energy efficiency of the entire electric heating element can be increased.

  Hereinafter, with reference to drawings, the structure of the electric heating body used as embodiment of this invention is demonstrated.

[First Embodiment]
First, with reference to FIG. 1 thru | or FIG. 3, the structure of the electric heating body used as the 1st Embodiment of this invention is demonstrated.

  As shown in FIG. 1, the electric heating element 1 according to the first embodiment of the present invention is made of a core 2 and a metal (for example, a stainless alloy such as SUS410) that holds the core 2 from the outermost peripheral side of the core 2. The outer cylinder 3 is comprised. The core 2 is formed by winding the strip-like flat thin plate 5 and the corrugated thin plate 6 alternately and continuously around the center electrode 4. The flat thin plate 5 and the corrugated thin plate 6 are made of a metal such as an Fe—Cr—Al alloy having a thickness of about 50 to 100 [μm].

  At least one surface of the flat thin plate 5 is covered with an insulating film. Thereby, the current supplied from the center electrode 4 flows along the flat thin plate 5 and / or the wave thin plate 6 and reaches the outer cylinder 3. The current reaching the outer cylinder 3 flows to the ground potential via an electrode (not shown). The value of the current flowing through the electric heater 1 is determined by the voltage applied to the center electrode 4 and the resistance value of the entire electric heater 1 according to Ohm's law.

  When both surfaces of the flat plate 5 are covered with an insulating film, the current supplied from the center electrode 4 flows only in the flat plate 5, only the wave plate 6, or both the flat plate 5 and the wave plate 6 in parallel. The path of the current supplied from the center electrode 4 can be set by the connection (contact) form of the flat thin plate 5 and the wave thin plate 6. When only one surface of the flat thin plate 5 is covered with the insulating film, the path of the current supplied from the center electrode 4 is one path at the portion where the flat thin plate 5 and the corrugated thin plate 6 are in contact with each other. In the part where the wave thin plate 6 is not in contact, there are two paths.

  As shown in FIG. 2, the wave thin plate 6 has a wave shape in which a peak portion, a substantially straight portion, and a valley portion are continuously formed in this order, and when the wave plate 6 is inserted into the outer cylinder 3, The trough is in contact with the flat thin plate 5. In this embodiment, as shown in FIGS. 3A and 3B, the corrugated sheet 6 in the region 6b corresponding to the peaks and valleys has a plate thickness of the corrugated plate 6 in the region 6a corresponding to the substantially straight portion. It is smaller than the plate thickness of 6.

  According to such a configuration, the resistance value of the region 6a is higher because the cross-sectional area is smaller than that of the region 6b. The cross-sectional area of the region 6a is smaller than the cross-sectional area of the region 6b, and the region 6a and the region 6b are in the same current path, so that the current density of the region 6a is higher than the current density of the region 6b. Furthermore, since the region 6b is in contact with the flat thin plate 5, the heating rate of the region 6b becomes slower than the heating rate of the region 6a when a part of the heat generation is taken away by the flat thin plate 5. Further, since the mass of the region 6a is smaller than the mass of the region 6b, the specific heat of the region 6a is smaller than the specific heat of the region 6b.

  Thereby, the temperature increase efficiency of the region 6a becomes higher than the temperature increase efficiency of the region 6b, and as a result, the energy efficiency of the entire electric heating element 1 can be increased. As will be described in detail later, the heating efficiency of the wave thin plate 6 varies depending on the lengths of the regions 6a and 6b and the ratio of the resistance values. By designing the optimum ratio, it is possible to increase the partial temperature raising efficiency while reducing the electric power used as the electric heating element 1, and as a result, the electric heating element 1 having high energy efficiency can be obtained.

  The inventors of the present invention evaluated the relationship between the ratio of the area 6a in the length direction of the corrugated sheet 6 and the energy efficiency by simulation. As a result, the ratio of the area 6a in the length direction of the corrugated sheet 6 is 40% or more. It has been found that high energy efficiency can be obtained when In the present embodiment, the resistance value and / or mass of the corrugated sheet 6 is partially changed. Similarly, the resistance value and / or mass of the area where the flat sheet 5 does not contact the corrugated sheet 6 is varied. Also good. Further, the resistance value and / or mass of both the flat thin plate 5 and the corrugated thin plate 6 may be partially changed.

  As shown in FIGS. 3A and 3B, the thickness of the corrugated sheet 6 is continuously set between the region 6a and the region 6b so as not to form a steep step between the region 6a and the region 6b. A region 6c to be changed (smoothly) is formed. According to such a configuration, it is possible to prevent stress due to the temperature difference from concentrating at the step between the region 6a and the region 6b, and to improve the durability of the wave thin plate 6.

  Since the region 6c functions as an inclination for die cutting when the thickness of the corrugated sheet 6 is changed using a press die, the productivity when forming the corrugated sheet 6 can be improved. it can. The inclined shape of the region 6c is desirably as smooth as possible, but may be determined within a reasonable design range. Specifically, the slope shape of the region 6c is made substantially linear, a minute bending radius is given to both ends of the region 6c, or both ends of the region 6c are curves in which all four terms of the first and second derivatives are zero. Or may be made into a shape.

  As is clear from the above description, according to the electric heating element 1 according to the first embodiment of the present invention, the resistance value of the region 6 a of the wave thin plate 6 that does not contact the flat thin plate 5 is changed to the wave contacting the flat thin plate 5. By making it higher than the region 6b of the thin plate 6, the temperature raising efficiency of the region 6a is made higher than the temperature raising efficiency of the region 6b. As a result, the energy efficiency of the entire electric heating element 1 can be increased.

  Here, it is expressed that the resistance value of the region 6a is higher than the resistance value of the region 6b. However, the configuration of the corrugated plate 6 shown in FIGS. 3A and 3B is that the mass of the region 6a is larger than the mass of the region 6b. It can also be interpreted as having been made smaller. By making the mass of the region 6a smaller than the mass of the region 6b, the specific heat of the region 6a becomes smaller than the specific heat of the region 6b, and as a result, the temperature raising efficiency of the region 6a can be increased.

  In the electric heating body 1, as shown in FIGS. 4 and 5A and 5B, a rib 6d extending in the length direction of the wave thin plate 6 may be formed in the vicinity of the center of the surface of the region 6a. By forming such ribs 6d, the strength of the region 6a, which is thinner than the region 6b, can be reinforced, and the mechanical strength of the entire electric heating element 1 can be improved. 5A and 5B, the height of the rib 6d is set so that the total value of the thickness of the corrugated plate 6 in the region 6a and the height of the rib 6d is substantially the same as the thickness of the corrugated plate 6 in the region 6b. Although designed, it does not necessarily have to be this height.

  The cross-sectional shape of the rib 6d is not particularly limited, but it is desirable that the rib 6d has a triangular shape or a trapezoidal shape in consideration of ease of punching when forming with a press die. In order to avoid stress concentration due to temperature distribution due to the presence of corners, the shape of the tip portion and side wall portion of the rib 6d is given a minute bending radius, or all four terms of the first and second derivatives. It is desirable to make the curve shape that is as smooth as possible, for example, by making the curve shape zero.

  In general, the bending radius of the wave thin plate 6 is small and the bending angle is large around several turns near the center electrode 4. For this reason, when the corrugated sheet 6 is processed, there is a possibility that durability of the corrugated sheet 6 may be reduced by applying a large stress to the corrugated sheet 6. Furthermore, since the bending angle of the corrugated plate 6 is not stable at several turns near the center electrode 4, it is difficult to position the region 6a and the region 6b, resulting in a longer production time or a worsened yield due to misalignment. There is a fear. Therefore, in the above embodiment, the region 6a and the region 6b are formed in all the windings of the wave thin plate 6, but the region from the center electrode 4 to the flat thin plate 5 or the wave thin plate 6 of several turns (about three turns) is the region. It is desirable not to form 6a and region 6b.

  The electric heating element 1 is formed by inserting the core 2 into the outer cylinder 3. At this time, the thin plate near the outer periphery of the core 2 is deformed, or the thin plate near the outer periphery of the core 2 is pushed into a narrow place. If the residual stress is generated, the durability of the wave thin plate 6 may be reduced. Therefore, in the above embodiment, the regions 6a and 6b having different plate thicknesses are formed on the entire circumference of the wave thin plate 6. However, the flat thin plate 5 or the wave thin plate 6 that is several turns (about three turns) from the outermost periphery. It is desirable not to form the region 6a and the region 6b. Even if there is a winding circumference in which the region 6a and the region 6b are not formed, since the ratio of the winding circumference to the entire length of the wave thin plate 6 is several percent, the influence on the heating efficiency is small. The ratio of the winding circumference in which the region 6a and the region 6b are not formed to the entire length of the corrugated sheet 6 can be appropriately set by the designer in consideration of productivity, durability, and temperature rise efficiency.

  In the present embodiment, the plate thickness in the region 6 a is made uniform, but the plate thickness of the region 6 a may be appropriately changed in the length direction of the wave thin plate 6. Specifically, by increasing the plate thickness of the region 6a from the central portion toward the end in the length direction, the resistivity of the region 6a is a distribution in which the vicinity of the central portion is maximized in the length direction of the wave thin plate 6. You may make it have a state. According to such a configuration, since the resistance value at the center of the region 6a is larger than the resistance value at the end in the length direction close to the region 6b, the heat generated in the region 6a is transferred to the flat thin plate 5 via the region 6b. By conducting, it is possible to prevent the temperature raising efficiency from decreasing.

[Second Embodiment]
Next, with reference to FIG. 6, FIG. 7 (a), (b), the structure of the electric heating body used as the 2nd Embodiment of this invention is demonstrated. The configuration of the electric heating body according to the second embodiment of the present invention is different from the configuration of the electric heating body according to the first embodiment only in the configuration of the wave thin plate 6. Only the configuration of the wave thin plate 6 will be described below, and the description of the other configurations will be omitted.

  In the present embodiment, a plurality of circular holes 7 are formed in the region 6a corresponding to the substantially straight portion of the wave thin plate 6 as shown in FIGS. According to such a configuration, since the cross-sectional area of the region 6a is partially reduced, the resistance value of the region 6a is shown in FIG. 7B as in the case of the electric heating element 1 according to the first embodiment. Thus, it becomes larger than the resistance value of the region 6b. Moreover, since the mass of the area | region 6a corresponding to a substantially straight part becomes smaller than the mass of the area | region 6b corresponding to a peak part and a trough part, the specific heat of the area | region 6a becomes smaller than the specific heat of the area | region 6b. Accordingly, similarly to the electric heating body according to the first embodiment, the temperature raising efficiency of the region 6a can be made higher than the temperature raising efficiency of the region 6b, and the energy efficiency of the entire electric heating body 1 can be increased.

  According to the electric heating element according to the second embodiment of the present invention, the hole 7 is formed partially rather than the entire surface of the corrugated plate 6, so that the hole is formed over the entire surface of the corrugated plate 6. Thus, the number of processes such as die cutting and machining can be reduced, and as a result, production time can be shortened and production efficiency can be improved. Further, since the number of holes and the number of holes formed can be reduced as compared with the case where holes are formed over the entire surface of the corrugated plate 6, the time and cost required for the maintenance of the mold and the processing tool can be reduced.

  In the present embodiment, as shown in FIG. 7B, the resistance value is changed at a predetermined interval and a predetermined period in the region 6a. However, by changing the diameter, number, and forming position of the holes 7, the corrugated sheet 6 The resistivity in the region 6a may be appropriately changed in the length direction. Specifically, as shown in FIGS. 8 and 9A, by arranging the holes 7 in the region 6a so that the holes 7 are formed at any position in the length direction of the wave thin plate 6, As shown in 9 (b), the resistance value of the region 6 a may always be larger than the resistance value of the region 6 b in the length direction of the wave thin plate 6. According to such a configuration, since the rate of change in the resistance value of the region 6a due to the formation of the hole 7 becomes continuous in the length direction of the wave thin plate 6, variation in the temperature rise efficiency in the region 6a is reduced. Thus, the heating efficiency can be made constant.

  As shown in FIG. 11B, by arranging the holes 7 so that the number of the holes 7 decreases from the center of the region 6a toward the end in the length direction as shown in FIGS. In addition, the resistivity of the region 6a may have a distribution state in which the vicinity of the center portion in the length direction of the wave thin plate 6 has a maximum value. According to such a configuration, since the resistance value at the center of the region 6a is larger than the resistance value at the end in the length direction close to the region 6b, the heat generated in the region 6a is transferred to the flat thin plate 5 via the region 6b. By conducting, it is possible to prevent the temperature raising efficiency from decreasing.

  As shown in FIGS. 12 and 13 (a), by forming and arranging the hole 7 so that the diameter of the hole 7 decreases from the center of the region 6a toward the end in the length direction, As shown, the resistivity of the region 6a may have a distribution state in which the vicinity of the central portion in the length direction of the wave thin plate 6 is a maximum value. According to such a configuration, since the resistance value at the center of the region 6a is larger than the resistance value at the end in the length direction close to the region 6b, the heat generated in the region 6a is transferred to the flat thin plate 5 via the region 6b. By conducting, it is possible to prevent the temperature raising efficiency from decreasing.

  In the present embodiment, the shape of the hole 7 is a circular shape, but the rectangular slit 8 extending in the length direction of the wave thin plate 6 as shown in FIGS. 14, 15 (a), (b), A rectangular slit 9 extending in the width direction of the corrugated sheet 6 as shown in 16, 17 (a), (b) may be formed instead of the hole 7. As shown in FIG. 15A or 16A, one slit 8 or 9 may be formed in the length direction or width direction of the wave thin plate 6, or FIG. 15B or FIG. As shown in b), a plurality of the thin wave plates 6 may be alternately formed in the length direction or the width direction.

  However, when the slits 8 and 9 have a completely rectangular shape, the stress of the corrugated plate 6 may be deteriorated due to stress concentration at the corners. Therefore, when the slits 8 and 9 are formed in a rectangular shape, it is desirable to add a bending radius to the corners to eliminate the corners. Further, the shape of the slits 8 and 9 may be an elliptical shape instead of a rectangular shape. The shapes of the holes 7 and the slits 8 and 9 may be other shapes such as a trapezoidal shape, a pentagonal shape, and a hexagonal shape.

[Other Embodiments]
The electric heating body of the first and second embodiments can be used as an electric heating catalyst body by supporting a catalyst on a thin plate. For example, by supporting a catalyst material using existing combustion catalyst technology on a thin plate, the electric heating body of this embodiment can be used as an electric heating combustion catalyst body. The electrically heated combustion catalyst body can increase the catalyst activity by raising the temperature of the catalyst by electrically heating the combustion gas before it is supplied even if the catalyst activity is low and the temperature is low.

  When the catalyst is supported on the wave heating plate 6 of the electric heating body according to the second embodiment, as shown in FIG. 18, all the holes 6 are blocked by the catalyst 10 due to the surface tension of the catalyst 10. It may be. Further, a part of the holes 6 may be blocked by the catalyst 10 and the other holes 6 may be of a size that is not blocked by the catalyst 10 as shown in FIG. For example, if the diameter of the hole 6 is about 0.1 [mm] or less, the hole 6 is blocked by the surface tension of the catalyst 10. However, if the diameter of the hole 6 is about 0.8 [mm] or more, it is difficult to be blocked by the surface tension of the catalyst 10.

  Even when all the holes 6 are blocked by the catalyst 10, the resistance value of the region 6a hardly changes because the catalyst 10 is an insulator. Therefore, the same catalyst area as when the holes 6 are not formed can be secured, and the combustion performance equivalent to that when the holes 6 are not formed can be realized. In addition, by using the holes 6 that are not blocked by the catalyst 10 as drain holes, the water generated inside can be discharged, and the water resistance of the catalyst 10 can be improved. Further, by using the holes 6 that are not blocked by the catalyst 10 as the air flow path, the mixing performance, pressure loss, and combustion performance of the combustion gas can be improved.

〔Example〕
Several examples of the electric heating element according to the present invention will be described below.

[Example 1]
In the electric heating body of Example 1, as shown in FIGS. 20 (a) and 20 (b), the horizontal distance from the peak portion of the corrugated sheet 6 to the next peak portion is 1.2 [mm], The vertical distance between the apexes of the peaks and valleys was 1.6 [mm], and the length of the substantially straight portion R2 was 1.0 [mm]. Further, by setting the bending radius and bending angle of the peak (valley) R1 to 0.3 [mm] and 180 [°], the length of the peak (valley) R1 is 0.3π (about 0.9). ) [Mm].

The ratio of the length of the substantially straight portion R2 in the length direction of the wave thin plate 6 was about 51 [%]. When the gas flow path surrounded by the flat thin plate 5 and the corrugated thin plate 6 is defined as a cell, the cross-sectional area of the cell is about 1.0 [mm ² ], and the cell density per square inch is about 670 [cpsi]. there were. The cell density was calculated by substituting the cell cross-sectional area value [mm ² ] into the formula (25.4 [mm ² ] / cell cross-sectional area).

  About the electric heating body of this Example 1, the power ratio, current density ratio, FIG. 21 shows the results of evaluating the temperature rise ratio in the substantially straight portion R2 and the change in the temperature rise ratio in the curved portion (peak portion and trough portion) R1 by simulation.

  Each ratio shown in FIG. 21 is normalized with each ratio being 1 when the hole area ratio is 0. The power ratio means the ratio of the power consumption of the wave thin plate 6 to the total power consumption. The current density ratio means the ratio of the average current density of the substantially straight portion R2 to the average current density of the curved portion R1 of the wave thin plate 6. The heating rate means the average heating rate.

  As shown in FIG. 21, the power ratio and the temperature rise ratio in the curved portion R1 decrease with the increase in the opening ratio of the wave thin plate 6, whereas the current density ratio and the temperature rise ratio in the substantially straight portion R2 are To increase. The decrease in the power ratio means that the resistance value of the entire corrugated sheet 6 increases as the hole area ratio increases, and the current value at the same voltage decreases according to Ohm's law. The decrease in the temperature rise ratio in the curved portion R1 means that the amount of heat generation in the curved portion R1 where the resistance value does not change with the decrease in the amount of current has decreased. The increase in the current density ratio results in a decrease in the current density in the curved portion R1, but the current density in the substantially linear portion R2 increases due to a decrease in the average cross-sectional area of the substantially linear portion R2 as the hole area ratio increases. Means that. An increase in the temperature rise ratio in the substantially straight portion R2 means that the current density in the substantially straight portion R2 is increasing.

  From the above results, it is found that increasing the hole area ratio of the substantially straight portion R2 can improve the heating efficiency of the substantially straight portion R2 while reducing the total power consumption of the electric heating element. However, when the hole area ratio of the substantially straight portion R2 is increased, the cross-sectional area of the substantially straight portion R2 is reduced, so that the strength and durability of the wave thin plate 6 may be reduced. Therefore, it is desirable to set the hole area ratio of the substantially straight portion R2 in consideration of mechanical strength, durability, and power / heating efficiency using mechanical or electrical engineering techniques.

[Example 2]
In the electric heating body of Example 2, as shown in FIG. 22 (a), the horizontal distance from the peak portion of the corrugated sheet 6 to the next peak portion is 2.0 [mm], and the apex and valley portion of the peak portion. The vertical distance from the apex of the substrate was 3.2 [mm], and the length of the substantially straight portion R2 was 2.2 [mm]. Further, by setting the bending radius and bending angle of the peak (valley) R1 to 0.5 [mm] and 180 [°], the length of the peak (valley) R1 is 0.5π (about 1.6). ) [Mm]. The ratio of the length of the substantially straight portion R2 in the length direction of the wave thin plate 6 was about 58 [%]. The cross-sectional area of the cell was about 3.2 [mm ² ], and the cell density per square inch was about 200 [cpsi]. In this embodiment, the resistance value of the wave thin plate 6 is partially changed. However, the resistance value of the flat thin plate 5 is changed by partially changing the plate thickness of the flat thin plate 5 as shown in FIG. May be partially changed.

Example 3
In the electric heating body of Example 3, as shown in FIG.22 (b), the horizontal direction distance from the peak part of the corrugated sheet 6 to the next peak part is 1.6 [mm], the peak part and trough part of the peak part The vertical distance from the apex of the straight line portion was 1.6 [mm], and the length of the substantially straight portion R2 was 0.5 [mm]. Further, by setting the bending radius and bending angle of the peak (valley) R1 to 0.4 [mm] and 180 [°], the length of the peak (valley) R1 is set to 0.4π (about 1.3). ) [Mm]. The ratio of the length of the substantially straight portion R2 in the length direction of the wave thin plate 6 was about 28 [%]. The cross-sectional area of the cell was about 1.0 [mm ² ], and the cell density per square inch was about 620 [cpsi].

Example 4
In the electric heating body of Example 4, as shown in FIG.22 (c), the horizontal direction distance from the peak part of the corrugated sheet 6 to the next peak part is 3.6 [mm], and the apex and trough part of the peak part The vertical distance from the top of the straight line portion was 1.8 [mm], and the length of the substantially straight portion R2 was 1.5 [mm]. Further, by setting the bending radius and bending angle of the peak (valley) R1 to 0.5 [mm] and 90 [°], respectively, the length of the peak (valley) R1 is set to 0.25π (about 0.2 mm). 8) Set to [mm]. The ratio of the length of the substantially straight portion R2 in the length direction of the corrugated sheet 6 was about 65 [%]. The cross-sectional area of the cell was about 3.2 [mm ² ], and the cell density per square inch was about 200 [cpsi]. In the present embodiment, the resistance value of the wave thin plate 6 is partially changed. However, the resistance value of the flat thin plate 5 is changed by partially changing the plate thickness of the flat thin plate 5 as shown in FIG. May be partially changed.

Example 5
In the electric heating body of Example 5, as shown in FIG.22 (d), the horizontal direction distance from the peak part of the corrugated sheet 6 to the next peak part is 1.8 [mm], and the apex and trough part of the peak part The vertical distance from the top of each of the two was 0.9 [mm], and the length of the substantially straight portion R2 was 0.27 [mm]. Further, by setting the bending radius and bending angle of the peak (valley) R1 to 0.5 [mm] and 90 [°], respectively, the length of the peak (valley) R1 is set to 0.25π (about 0.2 mm). 8) Set to [mm]. The ratio of the length of the substantially straight portion R2 in the length direction of the wave thin plate 6 was about 25 [%]. The cross-sectional area of the cell was about 0.8 [mm ² ], and the cell density per square inch was about 800 [cpsi].

[Change in ratio of energy efficiency with change in hole area ratio]
FIG. 24 shows the change in the ratio of the energy efficiency of the substantially straight portion R2 to the energy efficiency of the entire wave thin plate 6 with the change in the opening ratio O of the substantially straight portion R2, in other words, the average heating rate of the entire wave thin plate 6 It is a figure which shows the result of having simulated the change of the ratio of the average temperature increase rate of the substantially linear part R2 with respect to several high resistance part ratios (ratio which the length of the substantially linear part R2 accounts in the wave sheet 6) R. .

  As shown in FIG. 24, it can be seen that the ratio of energy efficiency changes variously according to the combination of the opening ratio O of the substantially straight portion R2 and the high resistance portion ratio R. It can also be seen that the energy efficiency change curve differs depending on the high resistance portion ratio R, and the optimum hole area ratio also differs. When the ratio is 1.0, the aperture ratio O is 0 [%], or when the energy efficiency of the entire corrugated sheet 6 is the same as when the aperture ratio O is 0 [%]. is there. Therefore, when the ratio is 1.0 or more, the overall energy efficiency is better than when the aperture ratio O is 0 [%], and when the ratio is less than 1.0, the overall energy efficiency is the aperture. This is when the rate O is worse than when it is 0 [%].

  The findings obtained from the simulation results shown in FIG. 24 are summarized as shown in FIG. FIG. 25 is a diagram showing a change in the opening ratio O with respect to the high resistance portion ratio R. The dotted line in FIG. 25 indicates a straight line that can obtain the same overall energy efficiency as when the opening ratio O is 0%, and indicates a branch point of the overall energy efficiency at a certain high resistance portion ratio R value. That is, the dotted line shown in FIG. 25 is obtained by approximating a point where the ratio shown by each curve in FIG. 24 becomes 1.0 after exceeding 1.0 to a straight line. = 0.825 × high resistance portion ratio R + 9.875.

  From the dotted line data shown in FIG. 25, it can be seen that the overall energy efficiency is improved when the hole area ratio O is lower than the value indicated by the dotted line at a certain high resistance portion ratio R value. Also, by increasing the hole area ratio O beyond the value indicated by the dotted line, it is possible to set the hole area ratio O to 0 [%] or to increase the resistance by making holes in the entire wave thin plate 6 to increase the resistance. It turns out that efficiency improves.

The solid line shown in FIG. 25 is a straight line indicating the hole area ratio at which the energy efficiency is the highest, and a plot of the hole area ratio O at the peak position of each curve in FIG. It approximates a curve. In this example, the solid line is represented by a straight line of the mathematical formula: hole area ratio O = 0.0029 × high resistance portion ratio R ² + 0.228 × high resistance portion ratio R + 7.6786. Therefore, the overall energy efficiency can be optimized by substituting the value of the high resistance portion ratio R determined by the cell shape into the above formula and calculating the aperture ratio O at that time. However, since the mathematical formulas of the dotted line and the straight line shown in this figure are obtained by approximation, the optimum opening ratio O is within the range of ± 10 [%] of the opening ratio O obtained by calculation. It can be judged that.

[Internal combustion engine]
FIG. 26 is a schematic diagram showing a configuration of a gasoline engine to which the electric heating body according to the present invention is applied. FIG. 26 shows only a gasoline engine, and other parts are not shown. In this example, the electric heater according to the present invention is applied to a gasoline engine, but it can also be applied to other internal combustion engines such as a diesel engine, a liquefied propane gas engine, and an ethanol engine. This internal combustion engine can be used as a power source for vehicles such as simple generators used in construction sites, steam locomotives, automobiles, buses, trucks, and motorcycles.

  In the gasoline engine shown in FIG. 26, air is first introduced into the engine 22 through the intake portion 21. As air is introduced, the compressed combustion gas is combusted and the piston is pushed down by the expansion of the combustion gas. Power from the crank 23 is transmitted to a tire drive shaft (not shown) via a transmission (not shown) by the pushed-down piston. Exhaust gas combusted in the engine 22 is introduced into the combustion device 25 via the exhaust part 24.

  In the combustion device 25, the electric heating body 1 according to the present invention is installed so that the center electrode 4 is positioned at the approximate center of the flow path through which the exhaust gas flows, and the electric heating body 1 uses electric power from the battery 27. Then, a part of the flow path through which the exhaust gas flows is heated. The exhaust gas is warmed by the electric heater 1 and purified by the combustion catalyst 26 installed on the downstream side of the electric heater 1. That is, the combustion catalyst 26 burns the unburned components and incompletely burned components of the fuel contained in the exhaust gas. Control of the whole gasoline engine including control of the electric heater 1 is executed by the controller 28.

[Combustion battery system]
FIG. 27 is a schematic diagram showing the configuration of a fuel cell system to which the electric heating element according to the present invention is applied. This fuel cell system can be used as a power source for electric vehicles such as household / industrial power generation hot water supply systems and fuel cell locomotives, fuel cell automobiles, fuel cell buses, fuel cell scooters and the like.

  In the fuel cell system shown in FIG. 27, a fuel cell 32 is mounted in a fuel cell case 31. The fuel cell 32 is formed by a fuel cell stack formed by stacking several tens to several hundreds of cathodes that are air electrodes and anodes that are fuel electrodes. In this fuel cell system, the air supplied from the compressor 33 is supplied to the moisture recovery device 35 via the air supply piping 34, and is humidified in the moisture recovery device 35 and then supplied to the cathode via the air supply piping 36. The The air used for power generation at the cathode is supplied to the moisture recovery device 35 via the air discharge pipe 37 as a cathode off gas, and is dehumidified in the moisture recovery device 35. The moisture recovered in the moisture recovery device 35 is used for air humidification. The dehumidified cathode off gas is introduced into the combustion device 25 via the exhaust pipe 38.

  The hydrogen supplied from the hydrogen tank 39 is supplied to the anode via the hydrogen circulation device 40 and the hydrogen supply pipe 41. Hydrogen used for power generation at the anode is again introduced into the hydrogen circulation device 40 through the hydrogen discharge pipe 42 as an anode off gas. Thus, hydrogen can be efficiently utilized by recycling and utilizing hydrogen. However, as the fuel cell 32 generates power, the concentration of impurities in the anode, such as water vapor and nitrogen, increases and the hydrogen concentration decreases, thereby reducing the power generation efficiency. Therefore, in this case, the anode off gas is introduced into the combustion device 25 through the exhaust pipe 38 by performing a purge process for opening the purge valve 43 installed on the downstream side of the hydrogen circulation device 40.

  In the combustion apparatus 25, the electric heating body 1 according to the present invention is installed so that the center electrode 4 is positioned at the approximate center of the flow path through which the anode off-gas and the cathode off-gas flow, and the electric heating body 1 is supplied from the battery 27. A part of the flow path through which the anode off-gas and cathode off-gas flow is heated using electric power. The anode off-gas and the cathode off-gas are warmed by the electric heater 1 and purified by the combustion catalyst 26 installed on the downstream side of the electric heater 1. That is, the combustion catalyst 26 burns hydrogen contained in the anode off gas. Control of the entire fuel cell system including control of the electric heater 1 is executed by the controller 28.

[Heating system]
FIG. 28 is a schematic diagram showing a configuration of a heating system to which the electric heating body according to the present invention is applied. This heating system can be used as a heater for a guest room such as a catalyst combustion type fan heater or a bus. In the heating system shown in FIG. 28, the air supplied from the air blower 51 is mixed with the fuel supplied from the fuel tank 53 via the fuel supply pipe 52 and then supplied to the electric heating catalyst body 1 according to the present invention. The The electrically heated catalyst body 1 is installed so that the center electrode 4 is positioned substantially at the center of the flow path through which air flows, and burns air mixed with fuel using electric power from the battery 27. Thereby, warm air is discharged from the downstream side of the electrically heated catalyst body 1. Control of the whole heating system including control of the electric heating catalyst 1 is executed by the controller 28.

  As mentioned above, although the embodiment to which the invention made by the present inventors was applied has been described, the present invention is not limited by the description and the drawings that form part of the disclosure of the present invention according to this embodiment. That is, it should be added that other embodiments, examples, operation techniques, and the like made by those skilled in the art based on this embodiment are all included in the scope of the present invention.

It is a perspective view which shows the whole structure of the electric heating body used as embodiment of this invention. It is a figure which shows the state which expand | deployed on the plane the flat thin plate and wave thin plate which comprise a core about the electric heating body used as the 1st Embodiment of this invention. It is the side view and perspective view which show the structure of the corrugated sheet shown in FIG. It is a figure which shows the state which expand | deployed on the plane the flat thin plate and wave thin plate which comprise a core about the modification of the electric heating body shown in FIG. It is the side view and perspective view which show the structure of the corrugated sheet shown in FIG. It is a figure which shows the state which expand | deployed on the plane the flat thin plate and wave thin plate which comprise a core about the electric heating body used as the 2nd Embodiment of this invention. FIG. 7 is a top view of the corrugated sheet shown in FIG. 6 and a diagram showing a distribution state of resistance values in the length direction. It is a figure which shows the state which expand | deployed on the plane the flat thin plate and wave thin plate which comprise a core about the modification of the electric heating body shown in FIG. FIG. 9 is a top view of the corrugated sheet shown in FIG. 8 and a diagram showing a distribution state of resistance values in the length direction. It is a figure which shows the state which expand | deployed on the plane the flat thin plate and wave thin plate which comprise a core about the modification of the electric heating body shown in FIG. It is a top view of the corrugated sheet shown in FIG. 10, and the figure which shows the distribution state of the resistance value of a length direction. It is a figure which shows the state which expand | deployed on the plane the flat thin plate and wave thin plate which comprise a core about the modification of the electric heating body shown in FIG. It is a top view of the corrugated sheet shown in FIG. 12, and a figure which shows the distribution state of the resistance value of a length direction. It is a figure which shows the state which expand | deployed on the plane the flat thin plate and wave thin plate which comprise a core about the modification of the electric heating body shown in FIG. It is a figure which shows the upper side figure of the corrugated sheet shown in FIG. It is a figure which shows the state which expand | deployed on the plane the flat thin plate and wave thin plate which comprise a core about the modification of the electric heating body shown in FIG. It is a figure which shows the upper side figure of the corrugated sheet shown in FIG. It is a figure which shows the state by which the hole formed in the wave thin plate was block | closed with the catalyst. It is a figure which shows the state by which the hole formed in the wave thin plate is not obstruct | occluded with the catalyst. FIG. 3 is a diagram illustrating a configuration of an electric heater according to the first embodiment. It is a figure which shows the result of having evaluated the electric power body shown in FIG. 20 about the change of the power ratio accompanying the change of a hole area ratio, a current density ratio, the temperature rising ratio in a substantially linear part, and the temperature rising ratio in a curve part. It is a figure which shows the structure of the electric heating body of Examples 2-5. It is a figure which shows the structure of the application example of the electric heating body of Example 2 and Example 4. FIG. It is a figure which shows the result of having evaluated the change of the ratio of the energy efficiency accompanying the change of the aperture ratio of a substantially linear part. It is a figure which shows the change of the aperture ratio with respect to a high resistance part ratio. It is a schematic diagram which shows the structure of the gasoline engine to which the electric heating body which concerns on this invention is applied. It is a schematic diagram which shows the structure of the fuel cell system with which the electric heating body which concerns on this invention is applied. It is a schematic diagram which shows the structure of the heating system to which the electric heating body which concerns on this invention is applied.

Explanation of symbols

1: Electric heating element 2: Core 3: Outer cylinder 4: Center electrode 5: Flat thin plate 6: Wave thin plate 7: Hole 8, 9: Slit

Claims (22)

  An electric heating element formed by continuously winding a flat thin plate and a wave thin plate around a center electrode, wherein at least one of the flat thin plate and the wave thin plate is in a region not in contact with the other thin plate. An electric heating element characterized in that the heating efficiency is higher than the heating efficiency of other regions.   2. The electric heating element according to claim 1, wherein the resistance value of the region not in contact with the other thin plate is higher than the resistance value of the other region, and / or the mass of the region not in contact with the other thin plate is other region. An electric heating element characterized by being less than the mass of.   3. The electric heating element according to claim 2, wherein the corrugated thin plate is formed by a substantially straight portion not in contact with the flat thin plate and a curved portion in contact with the flat thin plate, and a resistance value of the substantially straight portion is a resistance value of the curved portion. Electric heating element characterized by being higher.   The electric heating body according to claim 3, wherein a ratio of the substantially straight portion in the length direction of the corrugated sheet is 40% or more.   The electric heating body according to any one of claims 2 to 4, wherein the resistance value changes from the end portion in the length direction toward the center portion in a region where the resistance value is high. Characteristic electric heating element.   The electric heating body according to claim 5, wherein the resistance value on the end side is lower than the resistance value on the center side.   The electric heating body according to any one of claims 2 to 6, wherein the thickness of the region not in contact with the other thin plate is smaller than the thickness of the other region. .   8. The electric heating body according to claim 7, further comprising a plate thickness changing region for smoothly changing the thickness of the region not in contact with the other thin plate to the thickness of the other region.   The electric heating body according to claim 7 or 8, further comprising a strength reinforcing portion in a region not in contact with the other thin plate.   The electric heating body according to any one of claims 2 to 6, further comprising a plurality of holes in a region not in contact with the other thin plate.   The electric heating body according to claim 10, wherein the plurality of holes are arranged so that the plurality of holes are formed at any position in a length direction of the thin plate.   12. The electric heating element according to claim 10 or 11, wherein the aperture ratio of the thin plate due to the formation of the plurality of holes is within a range in which the overall energy efficiency is higher than when the holes are formed over the entire surface of the thin plate. An electric heating element characterized by being set to.   13. The electric heating element according to claim 12, wherein the aperture ratio of the thin plate due to the formation of the plurality of holes is set to a value close to the aperture ratio at which the overall energy efficiency is maximized. Electric heating body.   The electric heating body according to any one of claims 2 to 13, wherein a part of the entire circumference of the flat thin plate and the wave thin plate is in contact with the other thin plate. An electric heating element characterized in that the resistance value of the non-region is higher than the resistance value of the other region and / or the mass of the region not in contact with the other thin plate is smaller than the mass of the other region.   The electric heating body according to claim 14, wherein the partial winding is a winding outer than a predetermined winding from the center electrode.   16. The electric heating body according to claim 14, wherein the part of the winding is an inner winding of a predetermined winding from the outermost circumference.   The electric heating body according to any one of claims 1 to 16, wherein a catalyst is supported on at least one of the flat thin plate and the wave thin plate.   The electric heating body according to claim 17, wherein a plurality of holes are provided in a region not in contact with the other thin plate, and at least a part of the plurality of holes has a diameter covered with the catalyst by surface tension. Electric heating body.   An exhaust system comprising: the electric heater according to claim 17 or 18; and a combustion catalyst disposed downstream of the electric heater.   An internal combustion engine comprising the electric heating body according to any one of claims 1 to 18 in an exhaust system.   A fuel cell system comprising the electric heater according to any one of claims 1 to 18 in an exhaust system.   A heating system comprising the electric heating body according to any one of claims 1 to 18 in an exhaust system.

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