JP2016133021A - Exhaust emission control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exhaust emission control device capable of suppressing an increase in the thermal stress of a catalyst support of an electric heating type catalyst.SOLUTION: An exhaust emission control device 1 includes a housing 2, an electric heating type catalyst 3, an insulator 4, a holding mat 9, and electrical conductors 8, 15. The inner face of the housing, the outer peripheral face of the insulator, and the holding mat define an electrical connection chamber 6. One of the electrical conductors, extending from the outside of the housing to the inside of the housing while passing through a portion of the housing defining the electrical connection chamber, is connected to the other so that a current can flow through the surface of the insulator or the inside of the insulator into the electric heating type catalyst. The electric heating type catalyst is heated with the current flowing thereinto via the electrical conductors.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an exhaust emission control device.

  Conventionally, an exhaust purification device installed in an exhaust passage of an internal combustion engine using an electrically heated catalyst (EHC) is known. The electrically heated catalyst is a hydrocarbon (HC), carbon monoxide (CO), nitrogen oxide (NOx), etc. in the exhaust gas by rapidly heating the catalyst to the activation temperature when starting the internal combustion engine. Is to be removed. In general, an electrically heated catalyst includes a catalyst carrier that generates heat when an electric current is passed, and a pair of electrodes that are disposed opposite to each other so as to sandwich the catalyst carrier on the outer peripheral surface of the catalyst carrier. The catalyst carrier is usually cylindrical, has a plurality of honeycomb-shaped passages through which exhaust gas flows, and is covered with a metal housing. A holding mat made of an insulating material is arranged between the metal housing and the catalyst carrier. The holding mat holds the catalyst carrier in a fixed position in the housing and is arranged on the catalyst carrier. This prevents discharge and short circuit between the electrode and the metal housing when a current is passed through the electrode.

  In such an exhaust purification device using an electrically heated catalyst, the electrode disposed on the catalyst carrier is connected to a conductor for supplying electric power, and the conductor is disposed outside the exhaust purification device. It is connected to the power supply so that it can be energized. For such a conductor, for example, in the apparatus described in Patent Document 1, the holding mat disposed on the outer peripheral surface of the electrode has a notch. A conductor for supplying electric power from an external power source to the electrode disposed on the catalyst carrier is disposed through the notch. In addition, an electrical connection chamber for allowing a conductor to enter the housing provided with electrodes from the outside of the housing is provided in a portion of the housing located on the radially outer side of the notch portion of the holding mat. The electrical connection chamber is a space defined by the inner surface of the housing, the outer peripheral surface of the electrode disposed on the catalyst carrier, and the holding mat having a notch, and is made of a metal housing to prevent discharge and short circuit. It is comprised so that a predetermined distance may be ensured between the inner surface and the conductor. Furthermore, the space of the electrical connection chamber is also a space secured for facilitating the connection work of the conductor.

Japanese Patent No. 5263456 JP 2012-107597 A

  As described above, in the apparatus described in Patent Document 1, since the holding mat arranged on the outer peripheral surface of the electrode arranged on the catalyst carrier has a cutout portion, it is covered with the holding mat of the catalyst carrier. The heat dissipating property from the catalyst carrier to the outside is different between the portion where the cutout portion of the holding mat is disposed around. Specifically, the temperature of the portion of the catalyst carrier covered with the holding mat is unlikely to decrease, whereas the temperature is likely to decrease at the portion where the notch portion of the holding mat is arranged around. As a result, there is a temperature difference between these portions of the catalyst carrier, which may increase thermal stress. Accordingly, in view of such problems, an object of the present invention is to provide an exhaust purification device that can suppress an increase in thermal stress of a catalyst carrier in an electrically heated catalyst.

  In order to solve the above problems, according to a first aspect of the present invention, there is provided an exhaust purification device disposed in an exhaust passage of an internal combustion engine, the housing defining the exhaust passage therein, and the electric device disposed in the housing. Heated catalyst, an insulator disposed in the housing and disposed upstream or downstream in the exhaust flow direction of the electrically heated catalyst, and disposed between the outer peripheral surface of the electrically heated catalyst and the insulator and the housing A holding mat that holds the electrically heated catalyst and the insulator, and a conductor that supplies electric power to the electrically heated catalyst, and an electric connection chamber is formed by the inner surface of the housing, the outer peripheral surface of the insulator, and the holding mat. The conductor extends from the outside of the housing through the portion of the housing defining the electrical connection chamber to the inside of the housing and is electrically heated on the surface of the insulator or through the interior of the insulator. Are connected as a current can flow to the catalyst, the electrically heated catalyst, through a conductor is heated by passing an electric current through, the exhaust purification device is provided.

  According to the first aspect of the invention, it is possible to provide an exhaust emission control device that can suppress an increase in thermal stress of the catalyst carrier in the electrically heated catalyst.

1 is a schematic perspective view of an exhaust emission control device according to a first embodiment of the present invention. It is a fragmentary sectional view along the axial direction of the exhaust gas purification apparatus of FIG. It is a fragmentary sectional view along the axial direction of the exhaust gas purification apparatus which provided the electric connection chamber on the outer peripheral surface of an electrically heated catalyst. It is a fragmentary sectional view in alignment with the axial direction of the exhaust gas purification apparatus which concerns on 2nd embodiment of this invention. 5A is an enlarged view of the electrical connection chamber of FIG. 3, and FIG. 5B is an enlarged view of the electrical connection chamber of FIG. FIG. 5 is an enlarged view of the vicinity of an electrical connection chamber showing a wiring mode of a conductor in a modification of the second embodiment shown in FIG. 4. It is sectional drawing along the axial direction of the exhaust gas purification apparatus which concerns on 3rd embodiment of this invention. It is sectional drawing which shows the exhaust gas purification apparatus which concerns on the 1st modification of 3rd embodiment shown in FIG. It is a top view of the spacer which concerns on the 2nd modification of 3rd embodiment shown in FIG. It is the top view which looked at the spacer when the thickness of the radial direction of a spacer is made constant from the downstream. It is a top view of the spacer which concerns on the 3rd modification of 3rd embodiment shown in FIG. It is a fragmentary sectional view in alignment with the axial direction of the exhaust gas purification apparatus which concerns on 4th embodiment of this invention. It is a figure which shows the manufacturing process of the exhaust gas purification apparatus which concerns on this invention, and is a figure which shows the process of inserting an electric heating type catalyst in a housing. It is a figure which shows the process of inserting an insulator in the housing after the process shown in FIG. It is the schematic arrow view which looked at the exhaust gas purification apparatus of FIG. 14 in the direction of arrow A. It is a figure which shows the process of welding a relay conductor to a conductor further after the process shown in FIG. It is a figure which shows the process of arrange | positioning an insulator after the process shown in FIG. 16, connecting a conductor with a relay conductor, and arrange | positioning a lid | cover.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Corresponding components are marked with common reference numerals throughout the drawings.

  First, with reference to FIG.1 and FIG.2, the exhaust gas purification apparatus 1 which concerns on 1st Embodiment of this invention is demonstrated. FIG. 1 is a schematic perspective view of an exhaust emission control device 1 according to the present invention. FIG. 2 is a partial cross-sectional view along the axial direction of the exhaust purification device 1 of FIG.

  As shown in FIGS. 1 and 2, an exhaust purification device 1 includes a metal housing 2 provided in an exhaust passage of an internal combustion engine, a cylindrical electric heating catalyst 3 disposed in the housing 2, and insulation. And a body 4. The insulator 4 is arranged on the downstream side with respect to the electrically heated catalyst 3 in the flow direction of the exhaust gas from the internal combustion engine (not shown) shown in FIGS. 1 and 2.

  The electrically heated catalyst 3 includes a catalyst carrier 32 that generates heat when an electric current is passed, and a pair of electrodes 33 and 34 that are disposed opposite to each other so as to sandwich the catalyst carrier 32 on the outer peripheral surface of the catalyst carrier 32. . The catalyst carrier 32 has a plurality of honeycomb-shaped passages (cells) 7 through which exhaust gas flows. SiC or the like can be used as the material of the catalyst carrier 32, but materials other than SiC may be used as long as they are heat-resistant materials that generate heat when an electric current is passed. The catalyst carrier 32 supports a catalyst or the like so as to function as a three-way catalyst that removes harmful substances such as hydrocarbons, carbon monoxide, and nitrogen oxides.

  The insulator 4 is made of an insulating material excellent in temperature rise, such as cordierite and alumina, and has a plurality of honeycomb-shaped passages 7 through which exhaust gas flows, similarly to the electrically heated catalyst 3. The insulator 4 may be configured as a DPF (diesel particulate collection filter), or may be configured as a three-way catalyst, an oxidation catalyst, or the like. When the insulator 4 is disposed on the downstream side of the electrically heated catalyst 3, the exhaust gas temporarily stays between the electrically heated catalyst 3 and the insulator 4, and the heat of the exhaust gas is transferred to the electrically heated catalyst 3. This has the effect of assisting the heating of the electrically heated catalyst 3.

  An insulating coat 19 is applied to the inner peripheral surface of the housing 2. Further, a cylindrical holding mat 9 is disposed on the inner peripheral surface side of the housing 2. The holding mat 9 is in contact with the inner peripheral surface of the housing 2 on which the insulating coat 19 is applied on the outer peripheral surface thereof, and is in contact with the outer peripheral surfaces of the electric heating catalyst 3 and the insulator 4 on the inner peripheral surface thereof. The catalyst 3 and the insulator 4 are held in the housing 2. The holding mat 9 is made of an insulating material such as a ceramic fiber mainly composed of alumina and silica. When a current is passed through the electrodes 33 and 34 disposed on the catalyst carrier 32, the holding mat 9 is made of an electrode and a metal. It plays the role which prevents the electric discharge between the housings 2 and a short circuit. The holding mat 9 also plays a role of preventing the exhaust gas from touching the electrode and the conductor.

  The electrode 33 of the electrically heated catalyst 3 is connected to the conductor 8. The conductor 8 extends from the electrode 33 in the downstream direction between the outer peripheral surface of the electrically heated catalyst 3 and the holding mat 9 and in the downstream direction between the outer peripheral surface of the insulator 4 and the holding mat 9. Reach chamber 6. The electrical connection chamber 6 is a space defined by the inner surface 12 of the housing 2 partially protruding radially outward, the holding mat 9 provided with the notch 10, and the outer peripheral surface 14 of the insulator 4. is there. The notch 10 is a hole penetrating from the inner peripheral surface of the holding mat 9 to the outer peripheral surface. The electrical connection chamber 6 secures predetermined distances d1 and d2 between the inner surface 12 of the metal housing 2 and the conductor 8, thereby allowing the inner surface 12 of the housing 2 when a current flows through the conductor 8. And to prevent a short circuit and a short circuit between the conductor 8 and the conductor 8. Furthermore, the electrical connection chamber 6 is also a space reserved for facilitating connection work of the conductors 8 and 15 (see FIGS. 16 and 17).

  The conductor 8 that has reached the notch 10 along the inner peripheral surface of the holding mat 9 extends from the inside of the electrical connection chamber 6 to the outside in the radial direction of the insulator 4. The electric conductor 8 extending radially outward in the electric connection chamber 6 is connected in the electric connection chamber 6 with the electric conductor 15 passed from the outside of the housing 2 into the electric connection chamber 6. The conductor 15 is connected to an external power source (not shown) disposed outside the exhaust purification device 1.

  When electric power is supplied from an external power source, current is passed through the catalyst carrier 32 of the electrically heated catalyst 3 through the conductor 15, the conductor 8, and the electrode 33 to heat it. As a result, the catalyst carrier 32 is rapidly heated to reach the activation temperature of the catalyst, whereby the electrically heated catalyst 3 can remove hydrocarbons, carbon monoxide, nitrogen oxides and the like in the exhaust gas. Become.

  The other electrode 34 and the conductor (not shown) connected to this electrode 34 are not described in detail, but can be configured in the same manner as described above. Therefore, the electrode 34 and the conductor connected to the electrode 34 are provided with another electric connection chamber on the outer peripheral surface of the housing opposite to the electric conductor 8 by sandwiching the insulator 4 with respect to the electric connection chamber 6. Similarly, it may be connected to an external power source. Or you may connect with an external power supply through the electrical connection chamber 6 with the conductor 8 by the structure which ensures insulation with respect to the conductor 8. FIG.

  FIG. 3 differs from the present invention in the axial direction of the exhaust gas purification apparatus when the electric connection chamber 6 is provided not on the outer peripheral surface of the insulator 4 but on the outer peripheral surface of the electrode 33 of the electrically heated catalyst 3. It is a fragmentary sectional view. Comparing the first embodiment of the present invention shown in FIG. 2 with the example of FIG. 3, in the example shown in FIG. 2, the electrical connection chamber 6 is provided on the outer peripheral surface of the insulator 4, and therefore the holding mat 9 The notch 10 is also provided on the outer peripheral surface of the insulator 4. On the other hand, in the example shown in FIG. 3, since the electrical connection chamber 6 a is provided on the outer peripheral surface of the electric heating catalyst 3, the notch 10 a of the holding mat 9 is also provided on the outer peripheral surface of the electric heating catalyst 3. It is done.

  For this reason, in the example shown in FIG. 3, the temperature of the portion of the catalyst carrier 32 of the electrically heated catalyst 3 covered with the holding mat 9 is unlikely to decrease, whereas the notch 10 a of the holding mat 9. The temperature tends to decrease in the part where the is placed around. As a result, there is a temperature difference between these portions of the catalyst carrier 32, which may increase thermal stress. Further, the portion of the catalyst carrier 32 where the notch 10 a of the holding mat 9 is disposed around is not held on the outer peripheral surface by the housing 2 and the holding mat 9. For this reason, the stress acting on the outer peripheral wall of the catalyst carrier 32 may be locally concentrated in this portion due to the pressure of the exhaust gas passing through the inside of the catalyst carrier 32.

  On the other hand, the insulator 4 of the example shown in FIG. However, the insulator 4 is not energized and heated, so even if the thermal stress or the like increases in the insulator 4 shown in FIG. 2, it does not significantly affect the catalyst purification efficiency of the exhaust purification device 1. .

  Therefore, one feature of the exhaust emission control device according to the present invention is that a notch portion 10 for allowing the conductor 8 to pass is provided in a portion of the holding mat 9 disposed on the outer peripheral surface of the insulator 4. As a result, it is not necessary to provide the notch 10 in the holding mat 9 disposed on the outer peripheral surface of the electric heating catalyst 3, so that an increase in thermal stress or the like in the catalyst carrier 32 of the electric heating catalyst 3 is suppressed. The

  Next, a second embodiment of the present invention will be described with reference to FIGS. 4, 5A and 5B. FIG. 4 is a partial cross-sectional view along the axial direction showing the exhaust emission control device 11 according to the second embodiment. The configuration of the exhaust purification device 11 according to the second embodiment is basically the same as the configuration of the exhaust purification device 1 according to the first embodiment, except for the parts described below. In the present embodiment, the insulator 4a includes a through hole 16 extending from the outer peripheral surface to one of the plurality of honeycomb-shaped passages 7 (see FIG. 1). Further, in the present embodiment, the conductor 8 does not extend upstream along the outer peripheral surface of the insulator, but enters the passage 17 through the through hole 16 and passes through the passage 17. Extends upstream. Then, the conductor 8 exits from the passage 17 at the upstream end face of the insulator 4a and is connected to the electrode 33 of the electrically heated catalyst 3. Hereinafter, this will be described in detail with reference to FIGS. 5A and 5B.

  5A is an enlarged view of the electrical connection chamber 6a of FIG. 3 different from the present invention, and FIG. 5B is an enlarged view of the electrical connection chamber 6 of FIG. In both the example shown in FIG. 5A and the second embodiment shown in FIG. 5B, the electrical conductor 15 connected to an external power source (not shown) is connected to the electrical connection chamber 6 via the insulator 18 installed in the housing 2. It is common in that it extends into 6a and is connected to the conductor 8 in the electrical connection chambers 6 and 6a. Here, in the example shown in FIG. 5A, the conductor 8 is connected to the electrode 33 of the electrically heated catalyst 3 on the outer peripheral surface of the catalyst carrier 32. On the other hand, in the example shown in FIG. 5B, the conductor 8 reaches the passage 17 through the through hole 16 of the insulator 4a and extends in the upstream direction through the passage 17.

  By the way, in the example shown in FIG. 5A, the electrical connection chamber 6a is electrically conductive in order to prevent discharge and short circuit between the electrode 33, the conductors 8 and 15 and the metal housing 2 when a current is passed. The body 8 and the housing 2 need to be separated by a predetermined distance d1 to d3.

  In particular, in the example shown in FIG. 5A, since the electrode 33 is disposed on the outer peripheral surface of the catalyst carrier 32, measures are required to prevent discharge and short circuit between the electrode 33 and the inner surface of the housing 2. Become. For this reason, in the example shown in FIG. 5A, the insulating coat 19a is partially applied to the inner surface of the housing 2 in the electrical connection chamber 6a, thereby causing a discharge and a short circuit between the electrode 33 and the inner surface of the housing 2. A predetermined distance d3 for preventing is secured.

  On the other hand, in the exhaust emission control device of the second embodiment shown in FIG. 5B, the conductor 8 extends not through the outer peripheral surface of the insulator 4a but through the passage 17 in the insulator 4a. For this reason, it is not necessary to secure the predetermined distance d3 between the outer peripheral surface of the insulator 4a and the inner surface of the housing 2 in order to prevent discharge and short circuit. Therefore, it is not necessary to apply the insulating coat 19 to the inner surface of the housing 2 in the electrical connection chamber 6. Further, as a result, as shown in FIG. 5B, the insulator 18 can be disposed close to the insulator 4a. Accordingly, the upper surface of the housing 2 in FIG. 5B can be lowered below the upper surface of the housing 2 in FIG. 5A by a distance indicated by “S” in the drawing, and the entire volume of the electrical connection chamber 6 is reduced. It becomes possible.

  Next, a modification of the second embodiment of the present invention will be described with reference to FIG. FIG. 6 is an enlarged view of the vicinity of the electrical connection chamber 6 showing the wiring mode of the conductor in this modification. The configuration of the exhaust gas purification apparatus according to this modification is basically the same as the configuration of the exhaust gas purification apparatus according to the second embodiment described with reference to FIG. 4 except for the parts described below.

  In this modification, the branch through hole 20 extending between the passage 17 and the outer peripheral surface of the insulator 4b is formed in the insulator 4b. The branch through hole 20 is formed in a portion different from the portion facing the electrical connection chamber 6 on the outer peripheral surface of the insulator 4b. In the present modification, the conductor 8 extends from the electrical connection chamber 6 to the passage 17 via the through hole 16 as in the example shown in FIG. In addition, in the present modification, the conductor 8 that has reached the passage 17 in the insulator 4b is guided to the branch through hole 20 while extending the passage 17 in the upstream direction. The conductor 8 guided to the branch through-hole 20 reaches the outer peripheral surface of the insulator 4b, and then extends in the upstream direction along the outer peripheral surface of the insulator 4b, and is connected to the electrode 33 of the electrically heated catalyst 3. Is done. Also in this embodiment, since the bottom surface of the electrical connection chamber 6 is the outer peripheral surface of the insulator 4b, the volume of the electrical connection chamber 6 as a whole can be reduced for the same reason as shown in FIG. 5B. .

  Next, a third embodiment of the present invention will be described with reference to FIGS. FIG. 7 is a cross-sectional view similar to FIG. 4 of the exhaust purification device 21 according to the third embodiment. The configuration of the exhaust purification device 21 according to the third embodiment is basically the same as the configuration of the exhaust purification device according to the second embodiment except for the parts described below. In the exhaust emission control device 21 according to the third embodiment, the ring-shaped spacer 5 is disposed between the electrically heated catalyst 3 and the insulator 4a. The spacer 5 is disposed in contact with the electrically heated catalyst 3 on the upstream side and in contact with the insulator 4a on the downstream side. The spacer 5 is formed so that the radial thickness thereof is substantially constant over the entire circumference. Inside the spacer 5, a conductor passage 22 is formed that is inclined with respect to the axis of the electrically heated catalyst 3 and the insulator 4 a. In the present embodiment, the conductor 8 exiting upstream from the passage 17 on the upstream end face of the insulator 4a extends to the outer peripheral surface of the electrically heated catalyst 3 through the conductor passage 22 of the spacer 5 and is electrically heated. Connected to the electrode 33 of the catalyst 3. In addition, in this embodiment, the passage 17 of the insulator 4a through which the conductor 8 passes is sealed by the sealing plug 23 on the downstream side.

  According to the exhaust emission control device 21 according to the present embodiment, the conductor 8 is disposed so as to pass through the conductor passage 22 of the spacer 5, so that the conductor 8 includes the electric heating catalyst 3, the insulator 4 a, and the like. In contact with the exhaust gas is prevented. For this reason, it becomes possible to suppress the corrosion of the conductor 8 by the exhaust gas. Furthermore, in this embodiment, since the sealing plug 23 is installed at the downstream end portion of the passage 17, it is possible to prevent the exhaust gas from entering the passage 17 from the downstream side of the insulator 4a. For this reason, the conductor 8 passing through the passage 17 is also prevented from being exposed to the exhaust gas, whereby corrosion of the conductor 8 can be suppressed. Further, in the present embodiment, the spacer 5 is formed so that the thickness in the radial direction is substantially constant over the entire circumference, so that it can be easily manufactured as compared with the second modification described later. it can.

  Next, an exhaust purification device 21a according to a first modification of the third embodiment will be described with reference to FIG. FIG. 8 is a cross-sectional view similar to FIG. 7, showing an exhaust purification device 21a according to a first modification of the third embodiment described in FIG. In the exhaust emission control device 21a according to this modification, as shown in FIG. 8, a spacer 5a having a configuration different from that of the spacer 5 shown in FIG. 7 is arranged between the electrically heated catalyst 3a and the insulator 4a. The Specifically, the spacer 5a of this modification has an inclined portion 25 on its inner peripheral surface. The inclined portion 25 is shaped so that the inner circumference diameter of the spacer 5a increases from the downstream side to the upstream side in a state where the spacer 5a is disposed in the housing 2.

  By the way, in this 3rd embodiment, since the one end part is obstruct | occluded in the channel | path 24 of the electrically heated catalyst 3 by arrange | positioning the spacer 5, exhaust gas flows into this channel | path 24. It will disappear. For this reason, the electrically heated catalyst 3 cannot purify the exhaust gas around the passage 24. On the other hand, according to the spacer 5a of the present modification, the downstream end of the passage 24 of the electric heating catalyst 3a is not blocked by the spacer 5a, so the passage 24 located upstream of the arrangement position of the spacer 5a. The exhaust gas can also flow inside, and therefore, the exhaust gas can be purified also by these passages 24.

  Next, a second modification of the third embodiment will be described with reference to FIG. FIG. 9 is a plan view of a spacer 5b according to this modification. The ring-shaped spacer 5b according to this modification has a blocking portion 26 that protrudes radially inward only at a portion corresponding to one passage 17 of the insulator 4 in which the conductor 8 is disposed. The configuration is such that one passage 17 is closed. On the other hand, in the portion where the blocking portion 26 is not provided, the ring-shaped spacer 5b extends so as not to be positioned in front of the passage of the insulator 4, and therefore the conductor 8 is not disposed in the ring-shaped spacer 5b. The passage of the insulator 4 is configured not to be blocked.

  Here, let us consider a case where the thickness of the spacer in the radial direction is constant over the entire circumference as in the third embodiment and the first modification. FIG. 10 is a plan view of the spacer 5 viewed from the downstream side when the thickness of the spacer 5 is constant. In FIG. 10, the position corresponding to the outer peripheral surface of the electrically heated catalyst 3 or the insulator 4 a in a state where the spacer 5 is installed is indicated by a broken line, and the electrically heated catalyst 3 or the insulation in which the passage is blocked by the arrangement of the spacer 5. The blocking part 26a of the body 4a is indicated by hatching. In this figure, the conductor passage 22 is omitted. As can be seen from FIG. 10, when the thickness of the spacer 5 is made constant, the area occupied by the blocking portion 26 increases, so the number of passages of the catalyst carrier 32 or the insulator 4a through which the exhaust gas flows decreases. This reduces the purification efficiency of the electrically heated catalyst 3 and the insulator 4a. On the other hand, according to the second modified example, since the number of passages blocked by the blocking portions 26 can be reduced, a decrease in the number of passages of the catalyst carrier or insulator 4a for purifying the exhaust gas is suppressed. Thus, it becomes possible to improve the purification efficiency of the catalyst.

  Next, a third modification of the third embodiment will be described with reference to FIG. FIG. 11 is a plan view of a spacer 5c according to this modification. In this modification, a plurality of conductors 8 are disposed between the electrode 33 and the electrical connection chamber 6, and the plurality of conductors 8 are disposed so as to extend through a plurality of passages 17 adjacent to each other. The ring-shaped spacer 5c according to this modification has a blocking portion 26b protruding radially inward at a portion corresponding to the plurality of passages 17 of the insulator 4 in which the plurality of conductors 8 are arranged. In the example shown in FIG. 11, the blocking portion 26b is defined by an arc along the circumference of the spacer 5c and a chord portion extending between two points on the circumference. This blocking portion 26b is configured to block a plurality of adjacent passages 17 on the cross section of the insulator 4. On the other hand, in the portion where the blocking portion 26b is not provided, the ring-shaped spacer 5c extends so as not to be positioned in front of the passage of the insulator 4, and thus the plurality of conductors 8 are arranged in the ring-shaped spacer 5c. It is configured so as not to block the passage of the insulator 4 that is not. Therefore, even when the spacer 5c according to the present modification is disposed, the number of passages blocked by the blocking portions 26b can be reduced as in the case of the spacer 5b according to the second modification described with reference to FIG. Further, it is possible to suppress the decrease in the number of passages of the catalyst carrier or the insulator 4a for purifying the exhaust gas, thereby improving the purification efficiency of the catalyst.

  The passage 17 closed by the spacer 5c according to the present modification may be configured as one large passage by removing a partition between a plurality of adjacent passages on the cross section of the insulator 4. In this case, the shape of the conducting wire passing through the one large passage can be made larger than the shape of the conducting wire passing through the plurality of passages before removing the partition wall.

  Next, a fourth embodiment of the present invention will be described with reference to FIG. FIG. 12 is a partial cross-sectional view similar to FIG. 2 of the exhaust emission control device 31 according to the fourth embodiment. The configuration of the exhaust purification device 31 according to the fourth embodiment is basically the same as the configuration of the exhaust purification device 11 according to the second embodiment shown in FIG. 4 except for the parts described below.

  In the present embodiment, the insulator 4 c is disposed on the upstream side of the electric heating catalyst 35. Also in this embodiment, since the electrical connection chamber 6 is provided on the outer peripheral surface of the insulator 4c, the holding mat 9 disposed on the outer peripheral surface of the insulator 4c is electrically connected to the electrical connection chamber 6. It has a notch 10 through which the body 8 passes. On the other hand, since the electric connection chamber 6 is not provided on the outer peripheral surface of the electrode 37 of the electric heating catalyst 35, the holding mat 9 disposed on the outer peripheral surface of the electric heating catalyst 35 is notched 10. Does not have. As a result, as described in the first embodiment shown in FIG. 2, it is possible to suppress an increase in thermal stress in the catalyst carrier 36 of the electric heating catalyst 35.

  Furthermore, in the exhaust purification device 31 according to the present embodiment, the bottom surface of the electrical connection chamber 6 is the outer peripheral surface of the insulator 4c, similarly to the exhaust purification device 11 according to the second embodiment described with reference to FIGS. 4 and 5B. For the same reason as in the case of the exhaust emission control device 11 according to the second embodiment, the entire volume of the electrical connection chamber 6 can be reduced.

  Further, as in the case of the exhaust gas purification device 21 according to the third embodiment shown in FIG. 7, the spacer 5d and the sealing plug 23 are arranged to prevent the conductor 8 from coming into contact with the exhaust gas, and the exhaust gas. It is possible to suppress the corrosion of the conductor 8 due to the above.

  In the exhaust purification device 31 according to the present embodiment, the conductor 8 passes through the through hole 16 of the insulator 4c and passes through the inside of the insulator 4c, as in the exhaust purification device 11 according to the second embodiment shown in FIG. The passage 17 is extended to the electrode 37 of the electrically heated catalyst 35 from there. However, the conductor 8 according to this embodiment is similar to the case of the exhaust gas purification apparatus 1 according to the first embodiment shown in FIGS. 1 and 2, and the electrically heated catalyst 35 is along the outer peripheral surface of the insulator 4 c. It may be configured to extend to the electrode 37.

  Furthermore, in the exhaust purification device 31 according to the present embodiment, the spacer 5d is shown as a spacer similar to the spacer 5 of the exhaust purification device 21 according to the third embodiment shown in FIGS. It is also possible to use the spacers 5a, 5b and 5c according to the modification of the third embodiment shown in FIGS.

  Next, the manufacturing process of the exhaust purification device described above will be described with reference to FIGS. Hereinafter, the manufacturing process will be described by taking the exhaust purification apparatus 11 according to the second embodiment shown in FIG. 4 as an example. In manufacturing the exhaust emission control device 11, first, an insulating coat 19 is applied to the inner surface of the housing 2 in advance, and the holding mat 9 is disposed. In this state, as shown in FIG. 13, the electrically heated catalyst 3 having the electrode 33 connected to the conductor 8 a on the outer peripheral surface of the catalyst carrier 32 is inserted into the housing 2 in the direction of the arrow.

  Next, as shown in FIG. 14, the insulator 4 a is inserted into the housing 2 while passing the conductor 8 a through the passage 17. When manufacturing the exhaust emission control device 1 according to the first embodiment shown in FIGS. 1 and 2, the conductor 8a (which constitutes part of the conductor 8 described above) is disposed on the outer peripheral surface of the insulator 4a. The insulator 4a is inserted into the housing 2 so as to be disposed along. 6 is manufactured, the conductor 8a is passed through the passage 17 via the branch through hole 20 of the insulator 4b shown in FIG. Then, the insulator 4b is inserted into the housing 2. When manufacturing the exhaust emission control device 21 according to the third embodiment described with reference to FIG. 7, the spacer 5 is housed while passing the conductor 8 through the conductor passage 22 of the spacer 5 before the insulator 4a. Then, the insulator 4a is inserted by the method described above. When the sealing plug 23 described with reference to FIG. 7 is arranged, the sealing plug 23 is inserted into the passage 17 before or after the insulator 4a is inserted into the housing 2 in FIG.

  FIG. 15 is a schematic arrow view of the exhaust purification device of FIG. In the visual recognition state shown in FIG. 15, the conductor 8a can be visually recognized through the through-hole 16 that penetrates the insulator 4a. Therefore, while visually confirming the conductor 8a through the through hole 16, as shown in FIG. 16, the relay conductor 8b (which constitutes a part of the conductor 8 described above) is welded to the conductor 8a.

  Next, as shown in FIG. 17, the insulator 18 provided with the conductor 15 is arranged on the wall surface of the protruding portion of the housing 2. Thereafter, the conductor 15 is connected to the relay conductor 8b in the protruding portion of the housing 2, and the lid 28 is disposed on the protruding portion of the housing 2 to form the electrical connection chamber 6. This completes the manufacture of the exhaust emission control device. It should be noted that the electrode 34 (see FIG. 1) disposed facing the electrode 33 so as to sandwich the catalyst carrier 32 on the outer peripheral surface of the catalyst carrier 32 and the conductor (not shown) connected to the electrode 34 Although not described in detail, it can be manufactured by the same process as described above.

  In the present invention, the insulators 4, 4a, 4b, and 4c have been described as being made of an insulating material having excellent temperature rise properties such as cordierite and alumina. The object can be achieved and does not have to be a material with excellent temperature rise.

DESCRIPTION OF SYMBOLS 1 Exhaust purification device 2 Housing 3 Electrically heated catalyst 4 Insulator 5 Spacer 6 Electrical connection chamber 8 Conductor 9 Holding mat 10 Notch 32 Catalyst carrier 33 Electrode 34 Electrode

Claims (1)

An exhaust purification device disposed in an exhaust passage of an internal combustion engine,
A housing defining the exhaust passage therein;
An electrically heated catalyst disposed within the housing;
An insulator disposed in the housing and disposed upstream or downstream in the exhaust flow direction of the electrically heated catalyst;
A holding mat that is disposed between an outer peripheral surface of the electric heating catalyst and the insulator and the housing, and holds the electric heating catalyst and the insulator;
A conductor for supplying electric power to the electrically heated catalyst,
An electrical connection chamber is defined by the inner surface of the housing, the outer peripheral surface of the insulator, and the holding mat,
The conductor extends from the outside of the housing through the portion of the housing defining the electrical connection chamber to the inside of the housing, and on the surface of the insulator or through the interior of the insulator. Connected to be able to flow current to the electrically heated catalyst,
An exhaust emission control device, wherein the electrically heated catalyst is heated by passing an electric current through the conductor.

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