Electrically Heated Catalyst Device and Method for Manufacturing the Same

Abstract

Provided are an electrically heated catalyst device and a method for manufacturing the same. The electrically heated catalyst device includes a cylindrical catalyst carrier. A pair of electrode portions are mounted on the side surface of the catalyst carrier. A plurality of slits extending in the axial direction of the catalyst carrier are formed on the side surface of the catalyst carrier. A filler having a Young's modulus lower than that of the catalyst carrier is filled in each of the plurality of slits. The average Young's modulus is a value obtained by averaging the Young's modulus of the filler at each part of the slit over the entire length of the slit along the axial direction. The plurality of slits include a first slit having an average Young's modulus of a first value and a second slit having an average Young's modulus of a second value. The second value is smaller than the first value.

Description

Technical Field

[0001] The present disclosure relates to an electric heating type catalyst device. Moreover, the present disclosure relates to a method for manufacturing an electric heating type catalyst device. Background Art

[0002] As a catalyst device for exhaust gas purification of an internal combustion engine or the like, for example, an electric heating type catalyst device disclosed in Japanese Patent Application Laid-Open No. 2014-198296 is known. The electric heating type catalyst device described in the above document includes a cylindrical catalyst carrier having a honeycomb structure. A pair of electrode portions are attached to the side surface (outer peripheral surface) of the catalyst carrier. By applying a voltage between the electrode portions, current is passed through the catalyst carrier, thereby electrically heating the catalyst carrier.

[0003] Moreover, in the electric heating type catalyst device of the above document, a plurality of slits are formed in the side surface of the catalyst carrier. A filler is filled in the plurality of slits. Summary of the Invention

[0004] An electric heating type catalyst device provided by one aspect of the present disclosure includes a cylindrical catalyst carrier. A pair of electrode portions are attached to the side surface of the catalyst carrier. A plurality of slits extending in the axial direction of the catalyst carrier are formed in the side surface of the catalyst carrier in the electric heating type catalyst layer. A filler having a Young's modulus lower than that of the catalyst carrier is filled in each of the plurality of slits. Here, a value obtained by averaging the Young's modulus of the filler at each part of the slit over the entire length of the slit is referred to as the average Young's modulus. At this time, the plurality of slits include first slits having an average Young's modulus of a first value and second slits having an average Young's modulus of a second value. The second value is smaller than the first value.

[0005] If the catalyst carrier thermally expands, a compressive stress is applied to the filler in the gap. Corresponding to the deformation of the filler with respect to the compressive stress, the outer peripheral portion of the catalyst carrier is allowed to thermally expand in the circumferential direction. The greater the allowable thermal expansion amount of the catalyst carrier, the greater the decrease in the thermal stress of the catalyst carrier. That is, the greater the allowable thermal expansion amount of the catalyst carrier, the further the thermal stress of the catalyst carrier decreases. The amount of decrease in the thermal stress of the catalyst carrier is determined by the ease of deformation of the filler with respect to the compressive stress, that is, the Young's modulus of the filler. It should be noted that there are cases where the Young's modulus of the filler is not constant over the entire length of the gap. Considering such a case, it can be said that the amount of decrease in the thermal stress is determined by the above-mentioned average Young's modulus. Specifically, in the gap filled with a filler having a low average Young's modulus, the amount of decrease in the thermal stress of the catalyst carrier is larger than that in the gap filled with a filler having a high average Young's modulus. However, if the filler is filled into the gap in such a way as to decrease the average Young's modulus, the rigidity of the entire catalyst carrier decreases. In addition, if the filler is filled into the gap in such a way as to decrease the average Young's modulus, there is also a possibility that the amount of unpurified exhaust gas passing through the electric heating type catalyst device through the gap increases.

[0006] On the other hand, regarding the thermal stress generated in the catalyst carrier, a deviation occurs in each part of the catalyst carrier due to the temperature distribution and rigidity distribution of each part of the catalyst carrier. The temperature distribution of the catalyst carrier is generated due to the deviation of the flow rate and temperature of the exhaust gas flowing inside the catalyst carrier during the operation of the internal combustion engine. In addition, during electric heating, the temperature distribution in the catalyst carrier is also generated due to the deviation of the heat generation amount of each part of the catalyst carrier. Thus, during electric heating, the deviation of the thermal stress of each part of the catalyst carrier tends to increase.

[0007] Here, consider the case where the filler is filled in all the gaps in such a way that the average Young's modulus becomes the same value among the gaps. In this case, it is necessary to reduce the average Young's modulus of all the gaps in such a way that the thermal stress can be reduced to a value that can be tolerated even at the part where the thermal stress is the maximum.

[0008] In contrast, the electric heating type catalyst device having the above structure has a plurality of gaps with mutually different average Young's moduli. Thus, the gaps filled with the filler can be set in a suitable manner corresponding to the magnitude of the thermal stress generated in each part. For example, the gap at the part where a large thermal stress is generated is set as the second gap having a low average Young's modulus. On the other hand, the gap at the part where a large thermal stress is not generated so much is set as the first gap having a high average Young's modulus.

[0009] Consider a case where a plurality of slits are formed on the side surface of a catalyst carrier and a filler having a Young's modulus lower than that of the catalyst carrier is filled in the plurality of slits. Through the slits and the filler, relaxation of thermal stress generated in the catalyst carrier during electric heating can be achieved. It is conceivable to increase the heat shock resistance of the catalyst carrier during energization by making the depth of the slit directly below the electrode portion larger than that of the other slits.

[0010] Since the temperature distribution of the catalyst carrier during electric heating is not uniform, the thermal stress generated in the catalyst carrier also varies from part to part of the catalyst carrier. If the depth of the slit is increased, the thermal stress that can be relaxed also becomes larger. However, if the depth of the slit becomes larger, it will lead to a decrease in the rigidity of the catalyst carrier or a decrease in the exhaust gas purification area. Therefore, there is a limit to increasing the depth of the slit. Even if the depth of the slit is increased, it may not be possible to sufficiently relax the thermal stress at the part of the catalyst carrier that becomes hotter than other parts. The above structure suppresses such a possibility.

[0011] It should be noted that the first slit and the second slit can be formed, for example, in the following manner. The average Young's modulus of the second slit is smaller than that of the first slit. That is, the length of the portion filled with the filler in the first slit is made longer than the length of the portion filled with the filler in the second slit. In addition, by filling the second slit with a filler having a Young's modulus lower than that of the filler filled in the first slit, the average Young's modulus of the second slit can also be made smaller than that of the first slit. It should be noted that in the case of using a sintered body as the filler, the Young's modulus of the filler can be adjusted by the porosity of the sintered body. Therefore, in this case, a filler having a porosity larger than that of the filler filled in the first slit can also be filled in the second slit.

[0012] It should be noted that in the structure of many electric heating type catalyst devices, a pair of electrode portions are respectively arranged at positions opposite to each other across the central axis of the catalyst carrier. In an electric heating type catalyst device having such a structure, the part of the catalyst carrier where a larger thermal stress is generated than other parts during electric heating may be a part near the end of the electrode portion in the circumferential direction of the catalyst carrier. In such a case, the electrode portions respectively have ends in the circumferential direction of the catalyst carrier. It can be configured such that the second slit is located near the end of the electrode portion in the circumferential direction of the catalyst carrier.

[0013] According to another aspect of the present disclosure, there is provided a method for manufacturing an electro-heated catalyst device. The manufacturing method includes a step of preparing a cylindrical catalyst carrier. The manufacturing method includes a step of forming a plurality of slits extending in the axial direction of the catalyst carrier on the side surface of the catalyst carrier. The manufacturing method includes a step of filling each of the plurality of slits with a filler having a Young's modulus lower than that of the catalyst carrier. The average Young's modulus is a value obtained by averaging the Young's modulus of the filler at each part of the slit over the entire length of the slit along the axial direction. The manufacturing method includes a step of mounting a pair of electrode portions on the side surface of the catalyst carrier. The step of filling the plurality of slits with the filler includes a step of filling the first slit among the plurality of slits with the filler such that the average Young's modulus is a first value and a step of filling the second slit among the plurality of slits with the filler such that the average Young's modulus is a second value. The second value is smaller than the first value.

[0014] Please understand that the description “at least one of A and B” in this specification means “only A” or “only B” or “both A and B”. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is a front view of the electro-heated catalyst device of the first embodiment.

[0016] Figure 2 is Figure 1 a side view of the electro-heated catalyst device of

[0017] Figure 3 is Figure 2 a developed view of the side surface of the catalyst carrier in the electro-heated catalyst device of

[0018] Figure 4 is a diagram showing Figure 2 the flow pattern of current when the electro-heated catalyst device of

[0019] Figure 5 is a developed view of the outer peripheral surface of the catalyst carrier in the electro-heated catalyst device of the second embodiment.

[0020] Figure 6 The (a) part of Figure 2 is a coordinate diagram showing the Young's modulus distribution of the filler in the fully filled slits in the electro-heated catalyst device of the first embodiment of Figure 6 The (b) part of Figure 2 is a coordinate diagram showing the Young's modulus distribution of the filler in the partially filled slits in the electro-heated catalyst device of the first embodiment of

[0021] Figure 7Part (a) shows Figure 5 A graph showing the Young's modulus distribution of the filler in the high Young's modulus gap in the electro-heated catalyst device of the second embodiment. Figure 7 Part (b) shows Figure 5 A graph showing the Young's modulus distribution of the filler in the low Young's modulus gap in the electro-heated catalyst device of the second embodiment. Detailed implementation mode

[0022] (First embodiment)

[0023] Hereinafter, with reference to Figures 1 to 4 The first embodiment of the electro-heated catalyst device will be described in detail. It should be noted that the electro-heated catalyst device 10 of the present embodiment is provided in the exhaust passage of the internal combustion engine for purifying the exhaust gas of the on-vehicle internal combustion engine or the like.

[0024] <Structure of the electro-heated catalyst device 10>

[0025] First, with reference to Figure 1 and Figure 2 The structure of the electro-heated catalyst device 10 will be described. The electro-heated catalyst device 10 includes a cylindrical catalyst carrier 11. It should be noted that in the following description, the direction parallel to the central axis O of the cylinder when the catalyst carrier 11 is a cylinder is described as the axial direction A of the catalyst carrier 11. In addition, the circumferential direction around the central axis O is described as the circumferential direction C of the catalyst carrier 11.

[0026] The catalyst carrier 11 has a monolithic structure having a plurality of pore chambers that penetrate the catalyst carrier 11 in the axial direction A. The catalyst carrier 11 is, for example, a sintered body mainly composed of a composite of silicon and silicon carbide. Metal catalysts such as platinum, palladium, and rhodium are supported on the wall surfaces of the respective pore chambers of the catalyst carrier 11. It should be noted that in the following description, the Figure 2 left end of the catalyst carrier 11 is referred to as the front end 11a of the catalyst carrier 11. In addition, the Figure 2 right end of the catalyst carrier 11 is referred to as the rear end 11b of the catalyst carrier 11.

[0027] A pair of electrode portions 12 are provided on the side surface of the catalyst carrier 11 (in other words, the outer peripheral surface of the catalyst carrier 11). The electrode portions 12 are respectively provided at positions on the side surface of the catalyst carrier 11 that are opposite to each other across the central axis O. Each electrode portion 12 includes a first base layer 13, a second base layer 14, a metal electrode plate 15, and a fixing layer 16. The first base layer 13 is a layer made of conductive ceramic formed so as to be in contact with the side surface (outer peripheral surface) of the catalyst carrier 11. The second base layer 14 is formed on the surface of the first base layer 13. The second base layer 14 is a layer composed of a metal matrix and oxide mineral particles dispersed in the metal matrix. As the metal matrix, for example, NiCr alloy, MCrAlY alloy are used. It should be noted that "M" described here represents one or more of Fe, Co, and Ni. On the other hand, as the oxide mineral particles, for example, particles mainly composed of oxides such as silica and alumina and containing bentonite and mica are used. The metal electrode plate 15 is a comb-shaped plate made of a conductive metal such as Fe-Cr alloy. The metal electrode plate 15 is fixed to the surface of the second base layer 14 by a fixing layer 16 made of the same material as the second base layer 14. Each electrode portion 12 has an end 12a in the circumferential direction C and a center 12b. In the present embodiment, the first base layer 13 has the end 12a of the electrode portion 12 in the circumferential direction C.

[0028] In such an electrically heated catalyst device 10, electric heating of the catalyst carrier 11 can be performed. That is, when voltage is applied between the two electrode portions 12 to energize the catalyst carrier 11, the catalyst carrier 11 is heated by the heat generated corresponding to the energization. When the electrically heated catalyst device 10 is assembled in an internal combustion engine, the catalyst activity of the electrically heated catalyst device 10 is promoted by such electric heating of the catalyst carrier 11.

[0029] It should be noted that when the catalyst carrier 11 becomes high temperature due to electric heating or heat from the exhaust gas, thermal stress will be generated in the catalyst carrier 11. If such thermal stress is too large, it is considered that cracks may occur in the catalyst carrier 11. In the electrically heated catalyst device 10 of the present embodiment, gaps 30 to 37 for alleviating thermal stress are provided on the side surface of the catalyst carrier 11.

[0030] <Regarding the gaps 30 to 37 of the catalyst carrier 11>

[0031] Next, the structure of the gaps 30 to 37 of the catalyst carrier 11 will be described. On the side surface of the catalyst carrier 11, a plurality of gaps 30 to 37 extending in the axial direction A from the front end 11a to the rear end 11b of the catalyst carrier 11 are formed at intervals in the circumferential direction C. In the case of the present embodiment, eight gaps 30 to 37 are provided. Each of the gaps 30 to 37 has a rectangular cross-sectional shape. It should be noted that in the electro-heating type catalyst device 10 of the present embodiment, each of the gaps 30 to 37 is set to have the same size and shape.

[0032] Each of the gaps 30 to 37 is provided at the position described as follows. Here, as Figure 1 shown, a plane passing through the central portion of each electrode portion 12 in the circumferential direction C and also passing through the central axis O of the catalyst carrier 11 is referred to as a first plane P1. In addition, a plane passing through the central axis O of the catalyst carrier 11 and orthogonal to the first plane P1 is referred to as a second plane P2. It should be noted that the electro-heating type catalyst device 10 is configured to be symmetric with respect to the second plane P2. The gaps 30 and 34 are formed along the intersection line of the side surface (outer circumferential surface) of the catalyst carrier 11 and the first plane P1. In addition, the gaps 32 and 36 are formed along the intersection line of the side surface of the catalyst carrier 11 and the second plane P2. The remaining four gaps 31, 33, 35, and 37 are respectively formed in the middle portions between the gaps 30, 32, 34, and 36 on the side surface of the catalyst carrier 11. It should be noted that these four gaps 31, 33, 35, and 37 are located near the ends 12a of the two electrode portions 12 in the circumferential direction C.

[0033] Figure 3 The developed structure of a half-circumference amount of the side surface (outer circumferential surface) of the catalyst carrier 11 is shown. A filler 38 is filled in each of the gaps 30 to 37. The filler 38 has a Young's modulus smaller than that of the base material of the catalyst carrier 11. In the present embodiment, a sintered body mainly composed of silicon and its oxide is used as the filler 38. In the four gaps 31, 33, 35, and 37 formed near the ends 12a on the circumferential C side edges of the two electrode portions 12, the filler 38 is filled only at both ends in the axial direction A. In contrast, in the remaining four gaps 30, 32, 34, and 36, the filler 38 is filled over the entire length in the axial direction A. In the following description, the gaps 30, 32, 34, and 36 filled with the filler 38 over the entire length are referred to as fully filled gaps. In contrast, the gaps 31, 33, 35, and 37 filled with the filler 38 only at both ends in the axial direction A are referred to as partially filled gaps. The filler 38 is filled near the front end 11a and the rear end 11b of the catalyst carrier 11 in the partially filled gaps 31, 33, 35, and 37. The filler 38 is not filled in the middle portion in the axial direction A of the partially filled gaps 31, 33, 35, and 37.

[0034] <Function and Effect of Embodiment>

[0035] The function and effect of this embodiment will be described.

[0036] The electric heating type catalyst device 10 is assembled into the exhaust passage of the internal combustion engine. In the operation of the internal combustion engine, the catalyst carrier 11 of such an electric heating type catalyst device 10 becomes high temperature due to receiving electric heating and heat from the exhaust gas. In the state where the electric heating type catalyst device 10 is assembled in the exhaust passage, the thermal expansion of the catalyst carrier 11 accompanying the temperature rise is restricted. Thereby, thermal stress is generated in the catalyst carrier 11. In the electric heating type catalyst device 10 of this embodiment, gaps 30 to 37 for relaxing the thermal stress are provided on the side surface of the catalyst carrier 11. A part of the gaps 30, 32, 34, 36 are formed as fully filled gaps filled with a filler 38 over the entire length in the axial direction A. On the other hand, the remaining gaps 31, 33, 35, 37 are formed as partially filled gaps filled with the filler 38 only at both end portions in the axial direction A.

[0037] When the catalyst carrier 11 becomes high temperature and is about to thermally expand, the filler 38 in the gaps 30 to 37 is compressed. Corresponding to the deformation of the filler 38 caused by this compression, the thermal expansion in the circumferential direction C of the catalyst carrier 11 is allowed, and thus the thermal stress of the catalyst carrier 11 is relaxed. The greater the deformation of the filler 38 with respect to compression, that is, the lower the Young's modulus of the filler 38, the greater the amount of relaxation of the thermal stress at this time. In the partially filled gaps, there are portions where the filler 38 is not filled (that is, portions where the Young's modulus of the filler 38 can be considered to be "0"). Therefore, the partially filled gaps 31, 33, 35, 37 have a higher thermal stress relaxation effect than the fully filled gaps 30, 32, 34, 36.

[0038] On the other hand, the thermal stress generated in the catalyst carrier 11 has a deviation in each part due to the temperature distribution and rigidity distribution in the catalyst carrier 11. The temperature distribution in the catalyst carrier 11 is generated due to the flow rate of the exhaust gas flowing inside the catalyst carrier 11 during the operation of the internal combustion engine, and is generated due to the deviation of the exhaust gas temperature at each part of the catalyst carrier 11. In addition, the calorific value of the catalyst carrier 11 during electric heating is different depending on the part of the catalyst carrier 11, and thus a temperature distribution is also generated thereby. Therefore, during the electric heating of the electric heating type catalyst device 10, the deviation of the thermal stress in each part of the catalyst carrier 11 tends to become large.

[0039] Refer to Figure 4 to describe the temperature distribution and thermal stress distribution of the catalyst carrier 11 during electric heating in the electric heating type catalyst device 10 of this embodiment. In Figure 4FIG. schematically shows the flow of current during the electrical heating of the electro-heating type catalyst device 10 in the cross-section of the catalyst carrier 11 orthogonal to the central axis O. As described above, on the side surface of the catalyst carrier 11, two electrode portions 12 are provided at positions that are opposite to each other across the central axis O. During electrical heating, current flows through the interior of the catalyst carrier 11 from one electrode portion 12 to the other electrode portion 12. As Figure 4 shown, regarding the length of the conduction path between the electrode portions 12 inside the catalyst carrier 11, the portions of the two side ends 12a are shorter than the portions of the center 12b of the electrode portion 12 on the circumferential direction C. The shorter the conduction path, the smaller the resistance and the higher the current density. The higher the current density, the greater the heat generation. Therefore, in the side circumference of the catalyst carrier 11, the portions near the two side ends 12a of the circumferential direction C of the electrode portion 12 become hotter than other portions, and thus become portions where large thermal stresses are likely to occur.

[0040] In contrast, in the electro-heating type catalyst device 10 of the present embodiment, partially filled gaps 31, 33, 35, 37 that exhibit a high relaxation effect on thermal stress are provided in the portions that are likely to become hot. Thereby, the generation of excessive thermal stress is suppressed. It should be noted that if all the gaps 30 to 37 are set as partially filled gaps, the rigidity of the catalyst carrier 11 will be significantly reduced. In this regard, in the present embodiment, in the gaps 30, 32, 34, 36 other than the portions that are likely to become hot, a filler 38 is filled throughout the entire length. Thereby, the decrease in the rigidity of the catalyst carrier 11 is suppressed.

[0041] According to the electro-heating type catalyst device 10 of the present embodiment described above, the following effects can be achieved.

[0042] (1) The gaps 31, 33, 35, 37 provided in the portions that are likely to become hot are set as partially filled gaps that exhibit a high relaxation effect on thermal stress. In contrast, the gaps 30, 32, 34, 36 provided in the portions that do not become hot easily are set as fully filled gaps with a lower relaxation effect on thermal stress than the partially filled gaps. Thereby, accurate relaxation of thermal stress can be achieved in accordance with the temperature distribution of the catalyst carrier 11.

[0043] (2) It can be considered that by increasing the depth and width of the gaps, the relaxation effect of thermal stress can also be improved. However, if the depth and width of the gaps are increased, the exhaust gas purification area of the catalyst carrier 11 will be correspondingly reduced. In contrast, in the present embodiment, the relaxation effect of thermal stress of the gaps 31, 33, 35, 37 is improved by limiting the filling range of the filler 38. Thereby, the thermal stress of the catalyst carrier 11 can be relaxed without reducing the exhaust gas purification area.

[0044] (Second Embodiment)

[0045] Next, with reference to Figure 5 together, the second embodiment of the electric heating type catalyst device will be described in detail. It should be noted that in the present embodiment, regarding the structures common to the above-described embodiments, the same reference numerals are given, and the detailed description thereof is omitted.

[0046] In Figure 2 and Figure 3 in the first embodiment shown, in the gaps 31, 33, 35, 37 provided in the portions likely to become high temperature and the gaps 30, 32, 34, 36 provided in other portions, the filling range of the filler 38 is changed. The Young's modulus of the filler 38 is common. In contrast, in the present embodiment, in the gaps 31, 33, 35, 37 provided in the portions likely to become high temperature and the other gaps 30, 32, 34, 36, the Young's modulus of the filler filled in the gaps is changed.

[0047] Figure 5 The developed structure of a half-circumferential amount in the side surface of the catalyst carrier 11 in the electric heating type catalyst device of the present embodiment is shown. In the range of Figure 5 , gaps 31, 33 are provided in the portions of the catalyst carrier 11 likely to become high temperature (for example, near the end 12a in the circumferential direction C of the electrode portion 12). Gaps 32, 34 are provided in the portions of the catalyst carrier 11 less likely to become high temperature (for example, near the center 12b in the circumferential direction C of the electrode portion 12). In the present embodiment, the gaps 31, 33, 35, 37 provided in the portions likely to become high temperature are filled with a filler 39 having a Young's modulus lower than that of the filler 38 filled in the other gaps 30, 32, 34, 36. In the following description, the gaps 30, 32, 34, 36 filled with the high Young's modulus filler 38 as the filler having a higher Young's modulus are referred to as high Young's modulus gaps. In contrast, the gaps 31, 33, 35, 37 filled with the low Young's modulus filler 39 as the filler having a lower Young's modulus are referred to as low Young's modulus gaps. It should be noted that for the fillers 38, 39, sintered bodies of a common material are used. The Young's modulus of the two fillers 38, 39 is changed by adjusting the porosity of the sintered body.

[0048] The low Young's modulus filler 39 has a larger deformation when compressed compared to the high Young's modulus filler 38. Accordingly, the low Young's modulus gaps 31, 33, 35, 37 have a higher heat stress relaxation effect than the high Young's modulus gaps 30, 32, 34, 36. In the present embodiment, the gaps 31, 33, 35, 37 provided in the portions likely to become high temperature are configured as low Young's modulus gaps having a high heat stress relaxation effect. Thereby, the generation of excessive heat stress is suppressed.

[0049] On the other hand, the high Young's modulus filler 38 has a higher rigidity than the low Young's modulus filler 39. In the present embodiment, the high Young's modulus filler 38 is filled in the gaps 30, 32, 34, 36 provided in parts that do not become very hot. Thus, for example, compared with the case where the low Young's modulus filler 39 is filled in all of the gaps 30 to 37, in the present embodiment, the decrease in the rigidity of the catalyst carrier 11 is suppressed.

[0050] (Relationship between the filling method of the filler and the relaxation effect of thermal stress)

[0051] Next, the influence of the filling method of the filler on the relaxation effect of the thermal stress of the gap is examined. When the catalyst carrier thermally expands, a compressive stress is applied to the filler in the gap. Corresponding to the deformation of the filler with respect to this compressive stress, the outer peripheral portion of the catalyst carrier is allowed to thermally expand in the circumferential direction. The greater the amount of thermal expansion allowed for the catalyst carrier, the greater the amount of decrease in the thermal stress of the catalyst carrier. That is, the lower the Young's modulus of the filler, the greater the amount of decrease in the thermal stress of the catalyst carrier. In other words, the greater the amount of thermal expansion allowed for the catalyst carrier, the further the thermal stress of the catalyst carrier decreases. The lower the Young's modulus of the filler, the further the thermal stress of the catalyst carrier decreases. Thus, the Young's modulus of the filler becomes an index of the relaxation effect of the thermal stress of the catalyst carrier.

[0052] It should be noted that there are also cases where the filler is filled in a manner such that the Young's modulus is not constant throughout the entire length of the gap, such as in the partial filling of the gaps 31, 33, 35, 37 as described above Figure 2 and Figure 3 As an index value of the relaxation effect of the thermal stress of the catalyst carrier for the gap including the gaps with non-uniform Young's modulus of the filler, an average Young's modulus that can be described as follows can be used. The average Young's modulus is a value obtained by averaging the Young's modulus of the filler at each part of the gap over the entire length of the gap. It should be noted that when averaging the Young's modulus here, the Young's modulus of the filler at the unfilled part in the gap is regarded as "0". In such a case, as a general rule, it can be said that: compared with the gap filled with a filler having a large average Young's modulus, the relaxation effect of the thermal stress of the catalyst carrier is higher for the gap filled with a filler having a small average Young's modulus.

[0053] Figure 6 Part (a) of Figure 2 and Figure 3The Young's modulus of the filler 38 at each location from the front end 11a to the rear end 11b of the catalyst carrier 11 along the axial direction A in the first embodiment that fully fills the gaps 30, 32, 34, and 36. Figure 6 Part (b) of FIG. 1 also shows the Young's modulus of the filler 38 at each location from the front end 11a to the rear end 11b of the catalyst carrier 11 that partially fills the gaps 31, 33, 35, and 37 in the first embodiment. It should be noted that: Figure 6 "E1" in represents the Young's modulus of the sintered body used as the filler 38. Figure 6 The "L" in the figure represents the length of the axial direction A of the catalyst carrier 11, that is, the total length. In the fully filled gaps 30, 32, 34, 36 that are evenly filled with the filler 38 throughout the entire length, the Young's modulus of the filler 38 presents a constant value "E1" throughout the entire length. On the other hand, in the partially filled gaps 31, 33, 35, 37 that are filled with the filler 38 only at the two end portions in the axial direction A, the Young's modulus of the filler 38 outside the two end portions presents "0". The average Young's modulus of each of the fully filled gaps 30, 32, 34, 36 and the partially filled gaps 31, 33, 35, 37 corresponds to Figure 6 The quotient is obtained by dividing the area of ​​the hatched area by the length L. Figure 6 It is obvious that: Figure 6 The average Young's modulus of the partially filled gaps 31, 33, 35, and 37 shown in part (b) is Figure 6 The average Young's modulus of the fully filled gaps 30, 32, 34, and 36 shown in part (a) is small. In the first embodiment, the gaps 30, 32, 34, and 36 as fully filled gaps correspond to first gaps whose average Young's modulus presents a first value. In addition, the gaps 31, 33, 35, and 37 as partially filled gaps correspond to second gaps whose average Young's modulus presents a second value smaller than the above-mentioned first value.

[0054] Figure 7 Part (a) shows Figure 5 The Young's modulus of the filler 38 in each portion of the high Young's modulus gaps 30, 32, 34, 36 in the second embodiment from the front end 11a to the rear end 11b in the axial direction A of the catalyst carrier 11. In addition, Figure 7 Part (b) of FIG. 1 also shows the Young's modulus of the filler 39 in each portion from the front end 11a to the rear end 11b of the catalyst carrier 11 in the low Young's modulus gaps 31, 33, 35, and 37 in the second embodiment. It should be noted that: Figure 7"E1" in it represents the Young's modulus of the sintered body used as the high Young's modulus filler 38. "E2" represents the Young's modulus of the sintered body used as the low Young's modulus filler 39. The average Young's modulus of each of the high Young's modulus gaps 30, 32, 34, 36 and the low Young's modulus gaps 31, 33, 35, 37 corresponds to the quotient obtained by dividing the area of the region indicated by the hatching in Figure 7 by the length L. It is clearly known from Figure 7 that the average Young's modulus of the low Young's modulus gaps 31, 33, 35, 37 is smaller than that of the high Young's modulus gaps 30, 32, 34, 36. In the second embodiment, the gaps 30, 32, 34, 36 as the high Young's modulus gaps correspond to the first gaps whose average Young's modulus exhibits a first value. In addition, the gaps 31, 33, 35, 37 as the low Young's modulus gaps correspond to the second gaps whose average Young's modulus exhibits a second value smaller than the above first value.

[0055] The above embodiment can be implemented with the following changes. The present embodiment and the following modification examples can be implemented by combining each other within a range where there is no technical contradiction.

[0056] · In the above embodiment, in the side surface (outer peripheral surface) of the catalyst carrier 11, the portions near the ends 12a on both sides of the circumferential direction C of the electrode portion 12 become the portions most likely to become high temperature. Depending on the structure and configuration of the electrode portion, sometimes other portions (for example, the portion of the catalyst carrier 11 directly below the electrode portion) become the portions most likely to become high temperature on the side surface of the catalyst carrier 11. In such a case, it is preferable to appropriately change the configuration of the full-fill gaps / high Young's modulus gaps and the partial-fill gaps / low Young's modulus gaps in accordance with the temperature distribution of the catalyst carrier 11. Specifically, the gaps provided in the portions likely to become high temperature (for example, the center 12b in the circumferential direction of the electrode portion 12) are set as partial-fill gaps / low Young's modulus gaps. If it is configured such that the gaps provided in other portions (for example, the ends 12a in the circumferential direction C of the electrode portion 12) are set as full-fill gaps / high Young's modulus gaps, it can be achieved.

[0057] · It is also possible to appropriately change Figure 2 and Figure 7 the filled portions of the filler 38 in the partial-fill gaps 31, 33, 35, 37 of the first embodiment in the (b) part. For example, it is also possible not to fill the filler 38 at both ends in the axial direction A of the partial-fill gaps 31, 33, 35, 37, and only fill the filler 38 in the central portion in the axial direction A (i.e., the extending direction) of the partial-fill gaps 31, 33, 35, 37. In addition, it is also possible to Figure 2 and Figure 7In the (a) part of the first embodiment, a part of the gaps 30, 32, 34, 36 that are configured to be fully filled with the gap filler is provided with a portion where the filler 38 is not filled. The length of the portion filled with the filler 38 in the gaps 30, 32, 34, 36 is configured to be longer than the length of the portion filled with the filler 38 in the partially filled gaps 31, 33, 35, 37. In such a case, the average Young's modulus of the gaps 30, 32, 34, 36 is also larger than the average Young's modulus of the partially filled gaps 31, 33, 35, 37.

[0058] · In Figure 2 and Figure 6 the first embodiment, the average Young's modulus of the gap is changed by changing the filling range of the filler 38. In Figure 5 and Figure 7 the second embodiment, the average Young's modulus of the gap is changed by changing the Young's modulus of the fillers 38, 39. The average Young's modulus of the gap can also be changed in other ways. For example, in the partially filled gaps 31, 33, 35, 37 of the first embodiment, a low Young's modulus filler 39 having a lower Young's modulus than other parts is filled in the portion where the filler 38 is not filled. In such a case, the second value representing the average Young's modulus of the partially filled gaps 31, 33, 35, 37 also becomes a value smaller than the first value representing the average Young's modulus of the fully filled gaps 30, 32, 34, 36.

[0059] · The structure of the electro-heating type catalyst device including the number of gaps provided in the catalyst carrier 11 and the configuration and structure of the electrode part 12 can also be appropriately changed.

Claims

1. An electric heating type catalyst device, comprising: A cylindrical catalyst carrier; and A pair of electrode parts, mounted on the side surface of the catalyst carrier, wherein, A plurality of slits extending in the axial direction of the catalyst carrier are formed on the side surface of the catalyst carrier. Each of the plurality of slits is filled with a filler having a Young's modulus lower than that of the catalyst carrier. The average Young's modulus is a value obtained by averaging the Young's modulus of the filler at each part of the slit over the entire length of the slit along the axial direction. The plurality of slits include a first slit having an average Young's modulus of a first value and a second slit having an average Young's modulus of a second value, and the second value is smaller than the first value.

2. The electric heating type catalyst device according to claim 1, The length of the portion filled with the filler in the first gap is longer than the length of the portion filled with the filler in the second gap.

3. The electric heating type catalyst device according to claim 1 or 2, A filler having a Young's modulus lower than that of the filler filled in the first gap is filled in the second gap.

4. The electric heating type catalyst device according to claim 1 or 2, The filler is a sintered body, A filler having a porosity larger than that of the filler filled in the first gap is filled in the second gap.

5. The electric heating type catalyst device according to claim 1 or 2, The electrode parts respectively have ends in the circumferential direction of the catalyst carrier, The second gap is located near the ends of the electrode parts in the circumferential direction of the catalyst carrier.

6. A manufacturing method of an electric heating type catalyst device, wherein, The manufacturing method includes: a step of preparing a cylindrical catalyst carrier; a step of forming a plurality of slits extending in the axial direction of the catalyst carrier on the side surface of the catalyst carrier; a step of filling each of the plurality of slits with a filler having a Young's modulus lower than that of the catalyst carrier and the average Young's modulus is a value obtained by averaging the Young's modulus of the filler at each part of the slit over the entire length of the slit along the axial direction; and a step of mounting a pair of electrode portions on the side surface of the catalyst carrier. The step of filling each of the plurality of slits with the filler includes: a step of filling the first slit among the plurality of slits with the filler such that the average Young's modulus is the first value; and a step of filling the second slit among the plurality of slits with the filler such that the average Young's modulus is the second value, and the second value is smaller than the first value.

Images