JP2010001748A - Catalytic converter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a catalytic converter capable of increasing exhaust emission control performance and effectively increasing the output of an internal combustion engine. <P>SOLUTION: This catalytic converter in which first and second catalyst carriers are disposed in a housing in series with the flow of exhaust emission comprises; a housing 31 having a cylindrical peripheral wall 12, an upper wall 13 which seals the upstream end of the peripheral wall 12 and in which an exhaust emission inlet 17 is formed at the center portion, and a lower wall 14 which seals the downstream end of the peripheral wall 12 and in which an exhaust emission outlet 18 is formed at the center portion. The catalytic converter further comprises a catalytic carrier moving means 41 for axially moving the second catalyst carrier 31 between the upstream end movement position D where the exhaust emission inflow surface 32 thereof is brought into contact with the upper wall 13 and the downstream end movement position C where a chamber is formed, apart from the upper wall 13, between the upper wall 13 and the exhaust emission inflow surface 32. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a catalytic converter, and more particularly to a catalytic converter including a plurality of catalyst carriers.

  In a catalytic converter that is provided in an exhaust passage of an internal combustion engine and purifies harmful components in exhaust gas by passing a catalyst carrier carrying a catalyst, a portion of the catalyst carrier through which the exhaust gas passes according to the temperature of the exhaust gas A technique for effectively exerting the action of a catalyst by controlling the above is known.

  Patent Document 1 proposes a catalytic converter that exhibits a catalytic effect by providing a portion having a high cell density and a portion having a low cell density on one catalyst carrier. The outline | summary of the catalytic converter disclosed by this patent document 1 is demonstrated based on FIG.

  FIG. 8 is a longitudinal sectional view of the catalytic converter. As shown in the figure, the catalytic converter 100 includes a catalyst carrier 101 having a low cell density part 101A in which the cell density in the axial center is lower than the cell density of the peripheral part 101B, and the exhaust gas from the low cell density part 101A. A control valve 102 disposed downstream of the catalyst carrier 101 to control the flow and urged in a direction to shield the low cell density portion 101 of the catalyst carrier 101 by a compression spring 102A, and a housing 103 for housing the catalyst carrier 101 It consists of and.

  According to this configuration, when the temperature of the exhaust gas is low or when the engine is running at a low speed, the control valve 102 shields the low cell density portion 101A by the compression spring 102A that biases the low cell density portion 101A. maintain. If the inflow of exhaust gas to this portion is blocked, the exhaust gas flows into the peripheral portion 101B having a high cell density. On the other hand, when the temperature of the exhaust gas is high, or when the engine is rotating at high speed, the control valve 102 is set so as to be separated from the low cell density portion 101A and open the low cell density portion 101A. The flow of the exhaust gas into the peripheral part 101B having a high cell density is reduced by flowing through the central part having a low cell density.

  Therefore, when the temperature of the exhaust gas is low, the exhaust gas can be flowed into the peripheral portion 101B having a high cell density to improve the warm-up property of the catalyst, and the exhaust gas can be purified. When the temperature of the exhaust gas is high The high temperature exhaust gas is not applied to the peripheral portion 101B having a high cell density, thereby preventing thermal deterioration of this portion.

  Further, Patent Document 2 proposes a catalytic converter in which two catalyst carriers are arranged in series, and the catalyst effect is exhibited by adjusting the movement of the catalyst carrier on the discharge port side. The outline | summary of the catalytic converter disclosed by this patent document 2 is demonstrated based on FIG.

  FIG. 9 is a longitudinal sectional view of the catalytic converter. As shown in the figure, the catalytic converter 200 includes a cylindrical housing main body 203, a substantially cone-shaped upper housing 201A that is fitted on the upstream side of the housing main body 203 to form an exhaust gas inlet 201, and a housing. A housing 210 having a lower housing portion 202A that fits downstream of the main body portion 203 to form an exhaust gas discharge port 202, and an upstream second catalyst carrier 205 that is fitted and held in the housing main body portion 203. And the downstream first catalyst carrier 204 fitted and held so as to be movable in the axial direction between the second catalyst carrier 205 and the exhaust gas discharge port 202, and the first catalyst carrier 204 is moved in the axial direction. It comprises an advance / retreat drive unit 206.

  According to this configuration, when the temperature of the exhaust gas is low or when the engine is running at low speed, the catalyst body of the first catalyst carrier 204 is disposed by the second catalyst carrier 205 by arranging both catalyst carriers 204 and 205 close to each other. Can be activated. On the other hand, when the temperature of the exhaust gas is high or when the engine is running at high speed, the exhaust gas can be rectified in this separated space by arranging both catalyst carriers 204 and 205 apart from each other. Therefore, by adjusting the relative distance between the first catalyst carrier 204 and the second catalyst carrier 205, it is possible to suppress the drift of the exhaust gas in the first catalyst carrier 204 and improve the purification performance.

JP 2004-92512 A JP 2007-83189 A

  However, in the catalytic converter described in Patent Document 1, the exhaust gas inlet and the catalyst carrier are close to each other, and the chamber for diffusing the exhaust gas is not actively provided. Will pass through the catalyst carrier with a drift. Therefore, there is a concern that the expected effect of efficient purification of exhaust gas is not achieved. Furthermore, it is difficult to form a catalyst carrier in which different cell density portions are concentrically arranged, and the cell density in the radial direction, that is, the heat capacity is different. There is a concern that the difference will cause a decrease in durability. In addition, the thermal expansion absorbing means must be disposed in a limited space in the catalytic converter, which necessitates an increase in the size of the catalytic converter.

  Further, since the catalytic converter described in Patent Document 2 moves the first catalyst carrier in the direction of the exhaust gas outlet, the passage resistance of the exhaust gas by the second catalyst carrier fitted and held in the direction of the exhaust gas inlet is It is always constant, and does not increase the exhaust gas discharge capacity when the internal combustion engine rotates at high speed. Therefore, there is a concern that the output performance of the internal combustion engine at the time of high rotation is lowered.

  Accordingly, an object of the present invention made in view of the above points is to provide a catalytic converter that can effectively improve exhaust gas purification performance and output performance of an internal combustion engine, and is compact and excellent in durability. There is to do.

  According to a first aspect of the present invention, there is provided a catalytic converter according to a first aspect of the present invention, wherein a plurality of continuous cells are formed from an exhaust gas inflow surface to an exhaust gas discharge surface, and a catalyst body is supported. In the catalytic converter in which the catalyst carrier is arranged in series with respect to the exhaust gas flow in the housing, the housing seals the cylindrical peripheral wall and the upstream end of the peripheral wall and is provided with an exhaust gas inlet in the center. A first catalyst carrier which seals the upper wall and the downstream end of the peripheral wall and has a lower wall provided with an exhaust gas discharge port in the center, and is fitted and held in the housing; and an exhaust gas inflow surface A second catalyst carrier that is fitted and held in the housing so as to be movable in the axial direction between an upstream end moving position in contact with the upper wall and a downstream end moving position at which the exhaust gas inflow surface is separated from the upper wall; Upstream of the second catalyst carrier Further comprising a catalyst carrier moving means for moving in the axial direction between the moving position and the downstream end moving position and said.

  According to the present invention, when the second catalyst carrier is disposed at the downstream end movement position, the exhaust gas introduced into the housing from the exhaust gas introduction port is between the upper wall and the exhaust gas inflow surface of the second catalyst carrier. The exhaust gas diffused in the chamber formed in the gas chamber and injected into the second catalyst carrier from the entire exhaust gas inflow surface, and the exhaust gas flowing into the second catalyst carrier is rectified and purified in the second catalyst carrier. Since it flows into the first catalyst carrier, the exhaust gas is efficiently purified. Further, when the second catalyst carrier is arranged at the upstream end movement position, the exhaust gas inflow surface of the second catalyst carrier is not blocked at the upstream end movement position even if it is joined to the upper wall of the housing. Since exhaust gas concentrates and flows into the central portion, the exhaust gas flows into the first catalyst carrier without being diffused over the entire exhaust gas inflow surface of the second catalyst carrier. Therefore, the exhaust gas passage resistance can be reduced and the output performance of the internal combustion engine can be improved.

  Further, the use of the first catalyst carrier and the second catalyst carrier having a uniform cell density eliminates local unevenness of thermal expansion, thereby improving the durability of each catalyst carrier and obtaining a compact catalytic converter.

  A catalytic converter according to a second aspect of the present invention is the catalytic converter according to the first aspect, wherein the upper wall has a shape capable of being in close contact with an exhaust gas inflow surface of the second catalyst carrier moved to the upstream end moving position. It is characterized by being.

  According to the present invention, the exhaust gas inflow is prevented at the portion where the exhaust gas inflow surface of the second catalyst carrier is in close contact with the upper wall of the housing, so that the object of the invention according to claim 1 can be effectively achieved. . Moreover, since the outer part of the second catalyst carrier is not passed, thermal degradation of the second catalyst carrier is prevented.

  A catalytic converter according to a third aspect of the present invention is the catalytic converter according to the first or second aspect, wherein the second catalyst carrier penetrates from the exhaust gas inflow surface to the exhaust gas discharge surface along the axial direction. It has a communication hole.

  According to the present invention, when the second catalyst carrier is disposed at the upstream end movement position, when the exhaust gas flows into the catalytic converter, the exhaust gas actively flows into the communication hole. As a result, the exhaust gas passage resistance is reduced and the exhaust gas discharge capacity is increased, thereby improving the output performance of the internal combustion engine.

  On the other hand, when the second catalyst carrier is disposed at the downstream end movement position, the exhaust gas introduced into the housing from the exhaust gas inlet is formed between the upper wall and the exhaust gas inflow surface of the second catalyst carrier. The exhaust gas that diffuses in the chamber and flows into the second catalyst carrier from the entire exhaust gas inflow surface, and the exhaust gas that has flowed into the second catalyst carrier is rectified and purified in the second catalyst carrier, and then the first catalyst. Since it flows into the carrier, the exhaust gas is efficiently purified.

  A catalytic converter according to a fourth aspect of the present invention is the catalytic converter according to the third aspect, characterized in that the communication hole extends in the axial direction with the same diameter as the exhaust gas inlet.

  According to the present invention, after the exhaust gas flowing in from the exhaust gas inlet at the upstream end moving position of the second catalyst carrier is positively introduced into the communication hole of the second catalyst carrier without omission, the second catalyst carrier The exhaust gas passage resistance is reduced, and the exhaust gas flows into the first catalyst carrier while the flow rate of the exhaust gas is high. Therefore, the output performance of the internal combustion engine can be improved.

  A catalytic converter according to a fifth aspect of the present invention is the catalytic converter according to the third aspect, wherein the communication hole is opposed to the exhaust gas inlet and opens to the exhaust gas inflow surface and has the same diameter in the axial direction. It has the 1st communicating hole extended, and the taper-shaped 2nd communicating hole gradually diameter-expanded as it transfers to the said exhaust gas discharge surface from the downstream end of this 1st communicating hole, It is characterized by the above-mentioned.

  According to the present invention, the exhaust gas discharged from the first communication hole and the second communication hole gradually expands along the inner wall of the second communication hole, so that the local area of the exhaust gas on the exhaust gas inflow surface of the first catalyst carrier. Avoid inflow. Therefore, since the exhaust gas flows into the first catalyst carrier from the entire exhaust gas inflow surface of the first catalyst carrier after being rectified, the purification efficiency of the exhaust gas can be improved.

  A catalytic converter according to a sixth aspect of the present invention is the catalytic converter according to any one of the first to fifth aspects, wherein the catalyst carrier moving means detects an exhaust gas temperature sensor; And a control device that moves the second catalyst carrier in the axial direction between the upstream end moving position and the downstream end moving position based on a signal input from the sensor.

  The catalytic converter according to the invention of claim 7 is the catalytic converter according to claim 6, wherein the control device is configured to detect the second catalyst based on detection of an exhaust gas temperature below a predetermined temperature of the exhaust gas temperature sensor. The carrier is moved to the downstream end movement position and moved to the upstream end movement position based on detection of an exhaust gas temperature equal to or higher than a predetermined temperature.

  According to the sixth and seventh aspects of the invention, the control device moves the second catalyst carrier between the upstream end moving position and the downstream end moving position based on the exhaust gas temperature detected by the exhaust gas temperature sensor. It becomes possible. In the case of detecting the exhaust gas temperature below a predetermined temperature, the second catalyst carrier is disposed at the downstream end moving position and actively purified by the second catalyst carrier, and the purification efficiency is improved by increasing the rectifying action, In the case of detecting the exhaust gas temperature above a predetermined temperature, it is possible to improve the output performance of the internal combustion engine by arranging the second catalyst carrier at the upstream end movement position to reduce the exhaust gas passage resistance.

  The catalytic converter according to an eighth aspect of the present invention is the catalytic converter according to any one of the first to fifth aspects, wherein the catalyst carrier moving means includes an operational load detection sensor for determining an operational load of the internal combustion engine, And a controller that moves the second catalyst carrier in the axial direction between the upstream end moving position and the downstream end moving position based on a signal input from the sensor.

  The catalytic converter according to the invention described in claim 9 is the catalytic converter according to claim 6, wherein the control device moves the second catalyst carrier to the upstream side based on high operating load detection of the operating load detection sensor. It moves to an end moving position, and it is made to move to the said downstream end moving position based on low driving load detection.

  According to the eighth and ninth aspects of the invention, the control device can move the second catalyst carrier between the upstream end moving position and the downstream end moving position based on the driving load detected by the driving load detection sensor. It becomes. When a low operating load is detected, the second catalyst carrier is disposed at the downstream end movement position, diffused in a chamber formed between the upper wall and the exhaust gas inflow surface of the second catalyst carrier, and diffused into the second catalyst. In addition to improving the purification efficiency by the carrier, it is possible to improve the output performance of the internal combustion engine by reducing the exhaust gas passage resistance by arranging the second catalyst carrier at the upstream end moving position when a high operating load is detected. It becomes possible.

  The catalytic converter according to a tenth aspect of the present invention is the catalytic converter according to any one of the first to fifth aspects, wherein the catalyst carrier moving means measures an exhaust sound frequency when the exhaust gas is discharged. A frequency detection sensor, and a control device that moves the second catalyst carrier in the axial direction between the upstream end movement position and the downstream end movement position based on a signal input from the sensor, and the control device Is characterized in that the second catalyst carrier is moved to a position to resonate and muffle the exhaust sound caused by the exhaust gas flowing into the housing.

  According to this invention, based on the frequency of the exhaust sound detected by the exhaust sound frequency detection sensor, the control device causes the exhaust sound to be resonantly silenced by the chamber volume formed between the upper wall and the exhaust gas inflow surface of the second catalyst carrier. Since the second catalyst carrier is moved to the position, the optimum silencing action according to the operating state can be obtained.

  The catalytic converter according to an eleventh aspect of the present invention is the catalytic converter according to any one of the first to fifth aspects, wherein the catalyst carrier moving means measures an exhaust sound frequency when the exhaust gas is discharged. A frequency detection sensor, and a control device that moves the second catalyst carrier in the axial direction between the upstream end movement position and the downstream end movement position based on a signal input from the sensor, and the control device Is characterized in that the second catalyst carrier is moved to a position where the exhaust sound due to the exhaust gas flowing into the housing is increased.

  According to this invention, since the control device moves the second catalyst carrier to a position where the exhaust noise is increased based on the frequency of the exhaust noise detected by the exhaust sound frequency detection sensor, the exhaust of the upper wall and the second catalyst carrier. An optimum sound-increasing action according to the operating state is obtained by the chamber volume formed on the gas inflow surface. Accordingly, it is possible to improve the notification effect by the exhaust sound for a third party.

  A catalytic converter according to a twelfth aspect of the present invention is the catalytic converter according to any one of the first to eleventh aspects, wherein the first catalyst carrier has a density of the cells smaller than that of the second catalyst carrier. It is characterized by being.

  According to the present invention, by reducing the cell density, the passage resistance at the time of exhaust gas passage is reduced, so that the output performance of the internal combustion engine particularly during high load operation or when the exhaust gas temperature is equal to or higher than a predetermined temperature. Improvements can be made.

  A catalytic converter according to a thirteenth aspect of the present invention is the catalytic converter according to any one of the first to twelfth aspects, wherein the first catalyst carrier has a lower conversion efficiency than the second catalyst carrier. It is characterized by that.

  According to the present invention, rectification and primary purification are performed in the second catalyst carrier during low load operation or when the exhaust gas temperature is lower than a predetermined temperature, and during high load operation or when the exhaust gas temperature is higher than a predetermined temperature, Since the exhaust gas having a relatively small amount of harmful substances is discharged, the amount of the catalyst body supported on the first catalyst carrier can be reduced as compared with the second catalyst carrier. Therefore, the manufacturing cost can be reduced.

  A catalytic converter according to a fourteenth aspect of the present invention is the catalytic converter according to any one of the first to thirteenth aspects, wherein the third catalyst is fitted and held in the housing in the downstream direction of the first catalyst carrier. The method further comprises a carrier, wherein the conversion efficiency of the first catalyst carrier is lower than that of the second catalyst carrier, and the conversion efficiency of the third catalyst carrier is lower than that of the first catalyst carrier.

  According to the present invention, by providing three catalyst carriers, the exhaust gas rectifying and purifying action can be further improved, and the amount of the catalyst body supported on the third catalyst carrier can be reduced. Therefore, the manufacturing cost can be reduced.

  A catalytic converter according to a fifteenth aspect of the present invention is the catalytic converter according to the fourteenth aspect, wherein the third catalyst carrier is continuous from the exhaust gas inflow surface to the exhaust gas outflow surface by a partition inside. The first to third catalyst carriers have a cell density of the first catalyst carrier smaller than the cell density of the second catalyst carrier, and the first to third catalyst carriers have a smaller cell density than the first catalyst carrier. The cell density of the third catalyst carrier is smaller than the cell density of one catalyst carrier.

  According to the present invention, by providing the three catalyst carriers, the exhaust gas rectifying and purifying action is further improved, and by reducing the cell density of the third catalyst carrier, the passage resistance when exhaust gas passes is reduced. Therefore, in particular, it is possible to improve the output performance of the internal combustion engine during high load operation or when the exhaust gas temperature is equal to or higher than a predetermined temperature.

  A catalytic converter according to a sixteenth aspect of the present invention is the catalytic converter according to any one of the first to fifteenth aspects, wherein an exhaust gas inlet is provided in the housing instead of the housing, An exhaust gas discharge port formed by slidably fitting to the upstream housing, and a second housing and a downstream housing for fitting and fixing the first catalyst carrier, and the catalyst carrier moving means Instead, the upstream end moving position where the upper wall of the upstream housing contacts the exhaust gas inflow surface of the second catalyst carrier and the downstream end where the upper wall separates from the exhaust gas inflow surface of the second catalyst carrier according to the operating state. And an upper wall moving means for moving in the axial direction between the moving positions.

  According to the present invention, when the upstream housing is disposed at the downstream end movement position, the exhaust gas introduced into the housing from the exhaust gas introduction port is between the upper wall and the exhaust gas inflow surface of the second catalyst carrier. The exhaust gas diffused in the formed chamber and injected into the second catalyst carrier from the entire exhaust gas inflow surface, and the exhaust gas flowing into the second catalyst carrier is rectified and purified in the second catalyst carrier, Since it flows into one catalyst carrier, the exhaust gas is efficiently purified. In addition, when the upstream housing is disposed at the upstream end movement position, the exhaust gas inflow surface of the second catalyst carrier is not blocked at the upstream end movement position even if it is joined to the upper wall of the housing. Since exhaust gas concentrates and flows into the portion, the exhaust gas flows into the first catalyst carrier without diffusing into the entire exhaust gas inflow surface of the second catalyst carrier.

  Further, since the housing is simply moved in the axial direction, the manufacturing cost can be reduced. Further, since the structure is simple, the possibility of failure is low, and the reliability of the apparatus can be ensured.

  According to the present invention, when the second catalyst carrier is disposed at the downstream end movement position, the exhaust gas introduced into the housing from the exhaust gas introduction port is between the upper wall and the exhaust gas inflow surface of the second catalyst carrier. The exhaust gas diffused in the chamber formed in the gas chamber and injected into the second catalyst carrier from the entire exhaust gas inflow surface, and the exhaust gas flowing into the second catalyst carrier is rectified and purified in the second catalyst carrier. Since it flows into the first catalyst carrier, the exhaust gas is efficiently purified. Further, when the second catalyst carrier is disposed at the upstream end movement position, the exhaust gas concentrates and flows into the central portion of the exhaust gas inflow surface of the second catalyst carrier, so the exhaust gas inflow surface of the second catalyst carrier. The exhaust gas flows into the first catalyst carrier without the exhaust gas diffusing over the entire surface. Therefore, the exhaust gas passage resistance can be reduced and the output performance of the internal combustion engine can be improved.

(First embodiment)
Next, an embodiment of the catalytic converter will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view schematically showing the catalytic converter according to the present embodiment, and FIG. 2 is a cross-sectional view taken along the line II of FIG. As illustrated, the catalytic converter 10 includes a housing 11, and a first catalyst carrier 21 and a second catalyst carrier 31 that are fitted and held in the housing 11.

  The housing 11 seals a peripheral wall 12 formed in a cylindrical shape in the exhaust system of the internal combustion engine, and an upstream end of the peripheral wall 12, and an exhaust gas introduction port 17 communicating with the upstream exhaust pipe 16 is provided in the center portion. The upper wall 13 is provided with a lower wall 14 that seals the downstream end of the peripheral wall 12 and is provided with an exhaust gas discharge port 19 that communicates with the downstream exhaust pipe 18 at the center.

  The first catalyst carrier 21 has an exhaust gas inflow surface 22 and an exhaust gas discharge surface 23 and is formed in a cylindrical shape that is fitted and fixed to the housing inner wall 11 </ b> A of the housing 11. To the exhaust gas discharge surface 23 and has a honeycomb shape in which a large number of cells 24A serving as exhaust gas passages are formed, and a catalyst body such as Pt, Pd, Rh, etc. is supported thereon.

  The second catalyst carrier 31 is formed in a cylindrical shape having an exhaust gas inflow surface 32 and an exhaust gas discharge surface 33, and an exhaust gas passage that extends from the exhaust gas inflow surface 32 to the exhaust gas discharge surface 33 by a partition wall 34. A honeycomb body in which a large number of cells 34A are formed, and a catalyst body such as Pt, Pd, Rh is supported. The supported amount of the catalyst body of the second catalyst carrier 31 is supported by a predetermined amount more than the supported amount of the catalyst body of the first catalyst carrier 21. Further, since the cell 34A of the second catalyst carrier 31 is formed to have a smaller cross-sectional shape per cell than the cell 24A of the first catalyst carrier 21, the cell density is configured to be larger than that of the first catalyst carrier 21. The

  The second catalyst carrier 31 is formed with a communication hole 35 having a predetermined diameter a and penetrating from the exhaust gas inflow surface 32 to the exhaust gas discharge surface 33 in the axial direction. The predetermined diameter a is the same as that of the exhaust gas inlet 17 and, as will be described later, at the upstream end moving position where the second catalyst carrier 31 is in close contact with the upper wall 13, the communication hole 35 extends from the exhaust gas inlet 16. A continuous cylindrical hollow portion is formed.

  The second catalyst carrier 31 is fitted and accommodated in a cylindrical carrier case 36 fitted and held in the housing 11 so as to be movable in the axial direction. The carrier case 36 includes a cylindrical circumferential surface 37 that fits and holds the second catalyst carrier 31, a pair of stays 38 that are installed at two locations facing each other in the radial direction of the circumferential surface 37, and the housing inner wall 11 </ b> A. A seal ring 39 for sealing a gap between the peripheral surfaces 37 of the carrier case 36 is provided.

  FIG. 3A is a sectional view showing the structure of the seal ring 39, and FIG. 3B is a sectional perspective view of the seal ring 39. As shown in the drawing, the seal ring 39 is fitted and provided in an annular recess 37a having a concave cross section formed on the outer periphery of the peripheral surface 37 of the carrier case 36 that accommodates the second catalyst carrier. The seal ring 39 is formed in a tube shape having an inverted C-shaped cross section in which the side portion in the direction of the upper wall 13 of the housing 11 is opened and an intake port 39a for exhaust gas is provided. As a result, when exhaust gas flows into the catalytic converter 10, the exhaust gas pressure flows into the intake port 39a of the seal ring 39 and the seal ring 39 expands, so that the housing inner wall 11A and the peripheral surface 37 of the carrier case 36 The gap between is sealed. For example, the seal ring 39 may be coated with a coating material 39c after a heat-resistant material 39b such as a nickel alloy is formed as a base material.

  The carrier case 36 in which the second catalyst carrier 31 is fitted and accommodated is configured to be movable along the inner wall 11 </ b> A in the axial direction by the catalyst carrier moving means 41. The catalyst carrier moving means 41 includes a sensor group 42 including an exhaust gas temperature sensor 42A, an engine speed detection sensor 42B as an operating load detection means, and an exhaust sound frequency detection sensor 42C, and data from the sensor group 42. An ECU (Engine Control Unit) 43, which is a control device incorporating a map to be accumulated and analyzed, and an actuator 44 that drives the rod 44A according to a control command from the ECU 43 are provided.

  The rod 44 </ b> A is inserted into the insertion hole 16 </ b> A drilled in the upstream exhaust pipe 16 via the rod guide 16 </ b> B, and is coupled to a stay 38 provided in the carrier case 36 that fits and houses the second catalyst carrier 31.

  With the above configuration, the ECU 43 accumulates and analyzes data detected by each sensor in the sensor group, and drives the rod 44A to the actuator 44 based on the analysis result. Since this rod 44A is coupled to a stay 38 provided in the carrier case 36, the carrier case 36 in which the second catalyst carrier 31 is accommodated is driven in the axial direction along the inner wall 11A of the housing by driving the rod 44A. An upstream end moving position where the surface 32 is in contact with the upper wall 13 and the exhaust gas inflow surface 32 are separated from the upper wall 13, and a chamber allowing dispersion of exhaust gas is formed between the upper wall 13 and the exhaust gas inflow surface 32. It moves to the downstream end movement position.

  Next, the operation of the catalytic converter 10 will be described with reference to the drawings.

  4A shows the downstream end moving position C, which is the position of the second catalyst carrier 31 in the housing 11 when the internal combustion engine is warming up or under low load, and FIG. 4B shows the internal combustion engine. FIG. 5 is a cross-sectional view showing an upstream end moving position D that is a position of the second catalyst carrier 31 in the housing 11 after warm-up or at a high load.

  As shown in FIG. 4A, when the exhaust gas temperature sensor 42A detects the temperature of the exhaust gas and the ECU 43 determines that the internal combustion engine is in the process of warming up, or the engine speed detection sensor 42B When the rotational speed of the engine is detected and the ECU 43 determines that the internal combustion engine is in the low load stage, the ECU 43 operates the actuator 44 so that the carrier case 36 in which the second catalyst carrier 31 is accommodated is connected to the upper wall 13. The exhaust gas is dispersed so that the entire surface of the exhaust gas inflow surface 32 of the second catalyst carrier 31 can flow in a chamber formed between the exhaust gas inflow surface 32 of the second catalyst carrier 31 and the first catalyst carrier 31. The downstream end movement position at which the exhaust gas inflow surface 22 of the catalyst carrier 21 can receive the exhaust gas discharged from the exhaust gas discharge surface 33 of the second catalyst carrier 31 over the entire surface. It is placed.

  Exhaust gas from the internal combustion engine side flows into the housing 11 of the catalytic converter 10 via the upstream exhaust pipe 16, and the exhaust gas that has flowed into the housing 11 is between the upper wall 13 and the second catalyst carrier 31. The exhaust gas is diffused over the entire inflow surface of the exhaust gas inflow surface 32 and flows into the second catalyst carrier 31 from the exhaust gas inflow surface 32. The exhaust gas that has passed through the communication hole 35 and the outer peripheral cell 34A of the exhaust gas inflow surface 32 and has been purified by the catalyst body carried on the partition wall 34 has been rectified and then exhausted from the exhaust gas inflow surface 22 of the first catalyst carrier 21. Flow into.

  When the exhaust gas continuously flows from the upstream exhaust pipe 16, the temperature gradually increases after the internal combustion engine is started, and when the exhaust gas reaches a predetermined temperature, the catalyst carried on the partition wall 34 forming the cell 34A of the second catalyst carrier 31. The medium becomes the activation temperature, and the exhaust gas purification efficiency increases. The exhaust gas that has passed through the second catalyst carrier 31 is rectified by passing through the cell 34 </ b> A and is discharged from the exhaust gas discharge surface 33 of the second catalyst carrier 31. The rectified exhaust gas after the primary purification then flows into the exhaust gas inflow surface 22 of the first catalyst carrier 21. The second catalyst carrier 31 can exhaust the exhaust gas over the entire surface of the exhaust gas discharge surface 33 in a state where the exhaust gas is rectified, and the exhaust gas inflow surface 22 of the first catalyst carrier 21 It is arranged at the downstream end moving position C where the exhaust gas can be received as a whole. Similar to the second catalyst carrier 31, when exhaust gas whose temperature gradually rises after the internal combustion engine is started to flow continuously, the catalyst body supported on the partition wall 24 forming the cell 24 </ b> A of the first catalyst carrier 21 is activated. The secondary purification of the exhaust gas begins at the control temperature. The exhaust gas discharged from the exhaust gas discharge surface 23 of the first catalyst carrier 21 flows into the downstream exhaust pipe 18 in a secondary purified state.

  As shown in FIG. 4B, when the exhaust gas temperature sensor 92A detects the temperature of the exhaust gas and the ECU 43 determines that the internal combustion engine is warmed up, or the engine speed detection sensor 42B. When the ECU 43 detects the engine speed and the ECU 43 determines that the internal combustion engine is in the high load stage, the ECU 43 operates the actuator 44 so that the exhaust gas inflow surface 32 of the second catalyst carrier 31 is moved to the carrier case 36. To the upstream end moving position D where it is tightly joined to the upper wall 13 of the housing 11. As described above, since the communication hole 35 is formed to have the same diameter as the exhaust gas inlet 17 of the upstream exhaust pipe 16, the exhaust gas passing through the communication hole 35 is continuously guided into the catalytic converter 10.

  Since the second catalyst carrier 31 is disposed at the upstream end movement position D, and the exhaust gas inflow surface 32 is tightly joined to the upper wall 13 via the carrier case 36, the exhaust gas is blocked by the second catalyst carrier 31. Without passing through the cell 34 </ b> A, it passes through the communication hole 35 and flows into the exhaust gas inflow surface 22 of the first catalyst carrier 21.

  The exhaust gas that passes through the communication hole 35 flows into the exhaust gas inflow surface 22 of the first catalyst carrier 21 that has a very low passage resistance and a low cell density. The catalyst body carried on the partition wall 24 of the first catalyst carrier 21 purifies the exhaust gas, and the exhaust gas that has passed through the cell 24A is rectified and flows into the downstream exhaust pipe 18.

  Further, the exhaust sound frequency detection sensor 42C detects the frequency of the exhaust sound, and the ECU 43 operates the actuator 44 based on the detected exhaust sound frequency so that the exhaust sound is transmitted to the upper wall 13 and the second catalyst carrier 31. The second catalyst carrier 51 is moved to a position where it is attenuated by the resonance effect due to the chamber volume formed between the exhaust gas inflow surface 32.

  On the other hand, the ECU 43 operates the actuator 44 based on the exhaust sound frequency detected by the exhaust sound frequency detection sensor 42C based on the detected exhaust sound frequency, and the exhaust gas flows into the upper wall 13 and the second catalyst carrier 31. It is also possible to move the second catalyst carrier 31 to a position where the exhaust noise is increased by a resonance effect that becomes a chamber volume formed between the surface 32 and the surface 32.

  The numerical reference of the exhaust sound frequency and the movement position of the second catalyst carrier 51 in the catalytic converter 10 may be controlled by data stored in a map in the ECU 43, or the exhaust gas that the driver likes The sound may be controlled by a switch or the like.

  With the above configuration, when the internal combustion engine is warming up or in a low load stage, the second catalyst carrier 31 housed in the carrier case 36 is disposed at the downstream end movement position C. The exhaust gas diffuses widely across the entire inflow surface of the exhaust gas inflow surface 32 between the upper wall 13 and the second catalyst carrier 31. Further, the downstream end movement position C is also a position where the exhaust gas discharged from the exhaust gas discharge surface 33 of the second catalyst carrier 31 flows into the entire surface of the exhaust gas inflow surface 22 of the first catalyst carrier 21. The rectified and primarily purified exhaust gas flows into the exhaust gas inflow surface 22 of the first catalyst carrier 21. The amount of catalyst body supported on the cell 24A of the first catalyst carrier 21 is reduced by a predetermined amount from the amount of catalyst body supported on the second catalyst carrier 21, but the exhaust gas is absorbed by the second catalyst carrier 21. Since it flows into the 1st catalyst support | carrier 21 in the state primarily purified, a purification effect is performed efficiently. Therefore, it is possible to efficiently purify the exhaust gas in the middle of warming up or in the low load stage of the internal combustion engine in which unburned gas is easily generated.

  Further, since the second catalyst carrier 31 and the first catalyst carrier 21 are close to each other, the first catalyst carrier 21 is warmed by the reaction heat of the second catalyst carrier 21 that has received the inflow of exhaust gas, and is supported on the first catalyst carrier 21. The activated catalyst body is activated early, and the catalytic activity can be maintained. Furthermore, since the amount of the catalyst body supported on the first catalyst carrier 21 can be reduced as compared with the second catalyst carrier 31, the manufacturing cost can be reduced.

  On the other hand, when the internal combustion engine is warmed up or in a high load stage, the exhaust gas inflow surface 32 of the second catalyst carrier 31 is disposed at the upstream end movement position D via the carrier case 36 and the communication hole 35 is Since the exhaust gas introduction port 17 of the upstream exhaust pipe 16 has the same diameter and extends from the upstream exhaust pipe 16 to a position passing through the second catalyst carrier 31, the exhaust gas flowing from the upstream exhaust pipe 16 is It passes through the communication hole 35 of the second catalyst carrier 31 without receiving the passage resistance, and flows into the exhaust gas inflow surface 22 of the first catalyst carrier 21 having a low cell density. Therefore, the exhaust gas passage resistance can be reduced and the output performance of the internal combustion engine can be improved.

  Further, since the exhaust gas having a high temperature is allowed to flow into the communication hole 35 so as to be discharged without substantially passing through the second catalyst carrier 31, thermal degradation of the second catalyst carrier 31 is prevented, and the exhaust gas is prevented from flowing for a long time. Thus, the purification performance of the second catalyst carrier 31 can be maintained.

  Furthermore, when the exhaust sound frequency is equal to or higher than a predetermined value, the exhaust sound is attenuated by a resonance effect, so that the silencing effect can be improved. On the other hand, when the exhaust sound frequency is equal to or lower than the predetermined value, the exhaust sound is increased by the resonance effect, so that the effect of informing the third party can be improved.

  Further, the use of the first catalyst carrier and the second catalyst carrier having a uniform cell density eliminates local unevenness of thermal expansion, thereby improving the durability of each catalyst carrier and obtaining a compact catalytic converter.

(Second Embodiment)
Next, a second embodiment of the catalytic converter 10 will be described with reference to the drawings. FIG. 5 is a cross-sectional view schematically showing the catalytic converter according to the present embodiment. In FIG. 5, elements similar to those in FIGS. 1 to 4 are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in the figure, the second catalyst carrier 51 has a predetermined diameter “a” having the same diameter as that of the exhaust gas introduction port 17 at a position facing the exhaust gas introduction port 17 of the upstream exhaust pipe 16 on the exhaust gas inflow surface 52 and a shaft. The first communication hole 55A extending in the direction and the second communication hole 55C including a tapered partition wall having a diameter increasing from the downstream end 55B of the first communication hole 55A toward the exhaust gas discharge surface 53. A hole 55 is provided. As shown in FIG. 6, the second communication hole 55 </ b> C may be continuously formed stepwise with a stepped portion 56 having a predetermined width b in a cross-sectional view.

  With the above configuration, the exhaust gas that flows in from the exhaust gas inflow surface 52 and is discharged from the first communication hole 55A and the second communication hole 55C is along the inner wall of the second communication hole 55C. The exhaust gas gradually expands and diffuses on the exhaust gas discharge surface 53 so that it can uniformly flow into the entire exhaust gas inflow surface 22 of the first catalyst carrier 21. Therefore, local exhaust gas inflow at the exhaust gas inflow surface 22 of the first catalyst carrier 21 can be avoided, and exhaust gas purification efficiency can be improved.

(Third embodiment)
Next, a third embodiment of the catalytic converter 10 will be described with reference to the drawings. FIG. 7 is a cross-sectional view schematically showing the catalytic converter according to the present embodiment. In FIG. 7, elements similar to those in FIGS. 1 to 6 are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in the figure, the housing 61 has an upstream housing 62 in which an exhaust pipe introduction port 64A communicating with the exhaust gas introduction port is formed in the center portion of the upper wall 63, and a downstream exhaust pipe 18 communicating with the exhaust gas discharge port on the lower side. A downstream housing 65 coupled to the central portion of the wall 66 and slidably fitted into the upstream housing 62 is provided. In the downstream housing 65, the first catalyst carrier 21 and the second catalyst carrier 31 are fitted and fixed in the downstream exhaust pipe 18 direction and the upstream exhaust pipe 64B direction, respectively. Similarly to the first embodiment, an annular recess (not shown) having a concave cross section is formed on the peripheral edge 65A of the downstream housing 65, and a seal ring 39 is fitted around the periphery.

  The upstream exhaust pipe 64 </ b> B is fitted and inserted into a cylindrical exhaust pipe introduction port 64 </ b> A formed in the upstream housing 62, and the upstream housing 62 is moved in the axial direction to the peripheral edge of the downstream housing 65 by the housing upper wall moving means 71. It is configured to be movable along 65A. Similar to the catalyst carrier moving means 41, the housing upper wall moving means 71 includes a sensor group 42 including an exhaust gas temperature sensor 42A, an engine speed detection sensor 42B as an operating load detection means, and an exhaust sound frequency detection sensor 42C. And an ECU (Engine Control Unit) 43 which is a control device incorporating a map for collecting and analyzing data from the sensor group 42, and an actuator 44 for driving the rod 44A according to a control command from the ECU 43.

  When the exhaust gas temperature sensor 42A detects the temperature of the exhaust gas and determines that the internal combustion engine is warming up, or the engine speed detection sensor 42B detects the engine speed, and the ECU 43 ECU 43 operates the actuator 44 to disperse the exhaust gas between the upper wall 63 of the upstream housing 62 and the exhaust gas inflow surface 32 of the second catalyst carrier 31. Is moved to the downstream end moving position C shown in FIG.

  On the other hand, when the exhaust gas temperature sensor 42A detects the temperature of the exhaust gas and determines that the internal combustion engine is warmed up, or the engine speed detection sensor 42B detects the engine speed, the ECU 43 When it is determined that the internal combustion engine is in the high load stage, the ECU 43 operates the actuator 44 to move the upstream housing 62 to the upstream end moving position D where the upper wall 63 contacts the exhaust gas inflow surface 32 of the second catalyst carrier 31. Move to.

  Further, the exhaust sound frequency detection sensor 42C detects the frequency of the exhaust sound, and the ECU 43 operates the actuator 44 based on the detected exhaust sound frequency, and the exhaust gas inflow surface of the upper wall 63 and the second catalyst carrier. The upstream housing 63 is moved to a position where the exhaust sound due to the chamber volume formed between the two and 22 is attenuated by the resonance effect.

  On the other hand, the ECU 43 operates the actuator 44 based on the exhaust sound frequency detected by the exhaust sound frequency detection sensor 42 </ b> C based on the detected exhaust sound frequency, and the exhaust gas flows into the upper wall 63 and the second catalyst carrier 31. The upper end 65 </ b> B of the downstream end housing 65 is moved to a position where the exhaust noise is increased by the resonance effect due to the chamber volume formed between the surface 32.

  With such a configuration, the upstream end housing 62 can be moved in the axial direction, so that the manufacturing cost can be reduced. Further, since the structure is simple, the possibility of failure is low, and the reliability of the apparatus can be ensured.

  Note that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, in the above-described embodiment, the case where two catalyst carriers are provided has been described. However, the third catalyst carrier may be disposed further downstream than the first catalyst carrier 21. In this case, the cells of the third catalyst carrier are formed to have a larger volume per cell than the cells 24A of the first catalyst carrier 21, or the amount of catalyst supported is a predetermined amount from the amount of catalyst supported on the first catalyst carrier 21. You may reduce and form.

It is a cross-sectional schematic diagram of 1st Embodiment which concerns on this invention. It is II sectional drawing of FIG. It is the A section enlarged view, sectional drawing, and sectional perspective view of FIG. 1 which show a seal ring part. It is sectional drawing which shows the action | operation operation state of a catalytic converter. It is a cross-sectional schematic diagram of 2nd Embodiment which concerns on this invention. Similarly, it is a cross-sectional schematic diagram of a second embodiment according to the present invention. It is a cross-sectional schematic diagram of 3rd Embodiment which concerns on this invention. It is sectional drawing which shows the outline of the conventional catalytic converter. Similarly, it is sectional drawing which shows the outline of the conventional catalytic converter.

Explanation of symbols

10 catalytic converter 11 housing 12 peripheral wall 13 upper wall 21 first catalyst carrier 22 exhaust gas inflow surface 23 exhaust gas discharge surface 24 partition wall 24A cell 31 second catalyst carrier 32 exhaust gas inflow surface 33 exhaust gas discharge surface 34 partition wall 34A cell 35 communication Hole 36 Carrier case 41 Catalyst carrier moving means 42 Sensor group 43 ECU
44 Actuator

Claims (16)

In a catalytic converter in which a number of continuous cells are formed from an exhaust gas inflow surface to an exhaust gas discharge surface, and a plurality of catalyst carriers on which catalyst bodies are supported are arranged in series in the housing with respect to the exhaust gas flow.
The housing is
A cylindrical peripheral wall and the upstream end of the peripheral wall were sealed, and an upper wall provided with an exhaust gas inlet at the center and a downstream end of the peripheral wall were sealed and an exhaust gas outlet was provided at the center. Has a lower wall,
A first catalyst carrier fitted and fixed in the housing;
An axial movement between an upstream end moving position where the exhaust gas inflow surface is in contact with the upper wall and a downstream end moving position where the exhaust gas inflow surface is spaced from the upper wall is disposed upstream of the first catalyst carrier. A second catalyst carrier fitted and held in the housing as possible,
Catalyst carrier moving means for moving the second catalyst carrier in the axial direction between the upstream end moving position and the downstream end moving position according to the operating state;
A catalytic converter comprising: The upper wall is
2. The catalytic converter according to claim 1, wherein the catalytic converter has a shape close to an exhaust gas inflow surface of the second catalyst carrier moved to the upstream end moving position. The second catalyst carrier includes
The catalytic converter according to claim 1, further comprising a communication hole penetrating from the exhaust gas inflow surface to the exhaust gas discharge surface along the axial direction. The communication hole is
The catalytic converter according to claim 3, wherein the catalytic converter has the same diameter as the exhaust gas inlet and extends in the axial direction. The communication hole is
A first communication hole that opens in the exhaust gas inflow surface facing the exhaust gas inlet and extends in the axial direction with the same diameter;
A tapered second communication hole that gradually increases in diameter as it moves from the downstream end of the first communication hole to the exhaust gas discharge surface;
The catalytic converter according to claim 3, wherein: The catalyst carrier moving means includes
An exhaust gas temperature sensor for detecting the temperature of the exhaust gas;
An actuator for moving the second catalyst carrier between the upstream end moving position and the downstream end moving position;
A control device for moving the second catalyst carrier in the axial direction between the upstream end moving position and the downstream end moving position by the actuator based on the detected exhaust gas temperature of the gas temperature sensor;
The catalytic converter according to any one of claims 1 to 5, comprising: The controller is
The second catalyst carrier is moved to the downstream end movement position based on the exhaust gas temperature detection below the predetermined temperature of the exhaust gas temperature sensor, and is moved to the upstream end movement position based on the exhaust gas temperature detection above the predetermined temperature. The catalytic converter according to claim 6. The catalyst carrier moving means includes
Driving load detection means for determining the driving load of the internal combustion engine;
An actuator for moving the second catalyst carrier between the upstream end moving position and the downstream end moving position;
A control device for moving the second catalyst carrier in the axial direction between the upstream end movement position and the downstream end movement position based on a signal input from the sensor;
The catalytic converter according to any one of claims 1 to 5, comprising: The controller is
The second catalyst carrier is moved to the upstream end movement position based on a high driving load detection of the driving load detection means, and is moved to the downstream end movement position based on a low driving load detection. 6. The catalytic converter according to 6. The catalyst carrier moving means includes
An exhaust sound frequency detection sensor for measuring the exhaust sound frequency when the exhaust gas is discharged;
An actuator for moving the second catalyst carrier between the upstream end moving position and the downstream end moving position;
A controller for moving the second catalyst carrier in the axial direction between the upstream end moving position and the downstream end moving position by the actuator based on the measured exhaust sound frequency of the exhaust sound frequency detection sensor,
The control device
The catalytic converter according to any one of claims 1 to 5, wherein the second catalyst carrier is moved to a position where the exhaust noise caused by the exhaust gas flowing into the housing is resonantly silenced. The catalyst carrier moving means includes
An exhaust sound frequency detection sensor for measuring the exhaust sound frequency when the exhaust gas is discharged;
A control device for moving the second catalyst carrier in the axial direction between the upstream end moving position and the downstream end moving position based on a signal input from the sensor;
The control device
The catalytic converter according to any one of claims 1 to 5, wherein the second catalyst carrier is moved to a position where an exhaust sound due to the exhaust gas flowing into the housing is increased. The first catalyst carrier includes
The catalytic converter according to claim 1, wherein the density of the cells is smaller than that of the second catalyst carrier. The first catalyst carrier includes
The catalytic converter according to any one of claims 1 to 12, wherein the conversion efficiency of the second catalyst carrier is small. A third catalyst carrier fitted and held in the housing in the downstream direction of the first catalyst carrier;
14. The conversion efficiency of the first catalyst carrier is lower than that of the second catalyst carrier, and the conversion efficiency of the third catalyst carrier is lower than that of the first catalyst carrier. The catalytic converter according to item. The third catalyst carrier is
A catalyst carrier in which a large number of continuous cells are formed by a partition wall from the exhaust gas inflow surface to the exhaust gas outflow surface,
The first to third catalyst carriers are
The cell density of the first catalyst carrier is smaller than the cell density of the second catalyst carrier, and the cell density of the third catalyst carrier is smaller than the cell density of the first catalyst carrier. The catalytic converter according to claim 14. An exhaust gas introduction port is provided in the housing instead of the housing, and an exhaust gas discharge port is formed by slidably fitting to the upstream housing and the upstream housing, and the second catalyst carrier and the second catalyst carrier A downstream housing for fitting and fixing one catalyst carrier;
Instead of the catalyst carrier moving means, an upper end moving position where the upper wall of the upstream housing contacts the exhaust gas inflow surface of the second catalyst carrier and the exhaust gas inflow surface of the second catalyst carrier above the exhaust gas inflow surface of the second catalyst carrier according to the operating state. The catalytic converter according to claim 1, further comprising an upper wall moving unit that moves in an axial direction between the downstream end moving position where the walls are separated from each other.

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