JP2015190388A - Cooling mechanism for catalyst converter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cooling mechanism for a catalyst converter capable of suppressing thermal deterioration of a catalyst by efficiently lowering a catalyst temperature.SOLUTION: In a cooling mechanism 10 for a catalyst converter 20 for cooling the catalyst converter 20 which includes a catalyst case 21 incorporating a catalyst and having an exhaust introduction port 25 and an exhaust discharge port 26, the catalyst converter 20 includes a coolant case 40 having an opening 48 opened close to the exhaust discharge port 26 of the catalyst case 21 and covering a part or the whole of the catalyst case 21 through an outer surface 28 of the catalyst case 21 and the clearance S, and a coolant supply part 50 for supplying coolant from the exhaust introduction port 25 side when a temperature of the catalyst is raised to a temperature set in advance is provided in the clearance S between the coolant case 40 and the catalyst case 21.

Description

  The present invention relates to a cooling mechanism for a catalytic converter, and more particularly, to a cooling mechanism for a catalytic converter that incorporates a catalyst and has an exhaust inlet and an exhaust outlet.

  A catalytic converter is a device that is generally provided in an exhaust passage of exhaust gas discharged from an internal combustion engine, and purifies harmful components in the exhaust gas by passing the exhaust gas through a catalyst carrier containing a catalyst. .

  Since such a catalytic converter needs to activate the catalytic function by increasing the catalyst temperature, it may be arranged in the vicinity of the internal combustion engine in order to increase the catalyst temperature according to the combustion temperature in the internal combustion engine. is there.

  On the other hand, when the catalyst temperature becomes excessively high, the catalyst is thermally deteriorated. In such a case, it is necessary to lower the catalyst temperature. As such countermeasures, various techniques for cooling the catalyst to lower the catalyst temperature have been proposed.

  Patent Document 1 discloses an air cooling mechanism for a catalytic converter that cools the catalytic converter with running air or cooling air from a radiator fan.

  The air cooling mechanism of the catalytic converter is formed with an outer pipe that covers a part of the outer side of the catalytic converter and introduces cooling air into a space between the outer pipe and the outer side of the catalytic converter. , And control means for controlling the cooling air introduction means. The cooling air introduction means introduces cooling air from the running air and the radiator fan into the space to cool the catalyst via the catalytic converter.

JP 7-279653 A

  By the way, for example, when a large amount of unburned gas flows into the catalytic converter due to misfire due to a malfunction of the ignition device, or when a high load is continuously applied to the internal combustion engine due to a steep climb over a long distance, The catalyst temperature may become high due to a relative decrease in traveling wind introduced from the outside to the outer surface of the catalytic converter.

  In such a case, it is necessary to cool the catalyst. However, depending on the air cooling mechanism as described in Patent Document 1, the catalyst temperature is appropriately controlled in a wide operating range such as when the internal combustion engine is under low load and when under high load. Therefore, when the catalyst temperature rises excessively, there is a concern that the catalyst temperature cannot be lowered efficiently.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a cooling mechanism for a catalytic converter that can efficiently reduce the catalyst temperature and suppress the thermal deterioration of the catalyst.

  The cooling mechanism for a catalytic converter according to the first aspect of the present invention for solving the above-described problem is a cooling of a catalytic converter that cools a catalytic converter that includes a catalyst and includes a catalyst case having an exhaust inlet and an exhaust outlet. In the mechanism, the catalytic converter has an opening that opens close to the exhaust outlet of the catalyst case, and is a cooling unit that covers part or all of the catalyst case via an outer surface and a gap of the catalyst case. A cooling water supply unit that supplies a cooling water from the exhaust inlet side when the temperature of the catalyst rises to a preset temperature in the gap between the cooling water case and the catalyst case. It is characterized by providing.

  According to this configuration, when the catalyst temperature rises to a preset temperature, the cooling water supply unit supplies cooling water to the gap between the outer surface of the catalyst case and the cooling water case from the exhaust inlet side of the catalyst case. To do. Thereby, according to the operating range of the internal combustion engine, the catalyst temperature can be efficiently lowered, and thermal deterioration of the catalyst can be prevented.

  In addition, since the cooling water case has an opening that opens close to the exhaust discharge port of the catalyst case, when the exhaust gas is discharged from the exhaust discharge port of the catalyst case, the outer surface of the catalyst case and the cooling water The cooling water supplied to the gap with the case becomes substantially water vapor and is sucked into the exhaust gas from the opening.

  Therefore, since the cooling water is discharged to the outside together with the exhaust gas and discharged to the outside without staying in the gap, the situation that prevents warm-up particularly during the cold start of the internal combustion engine is reduced. Therefore, the function deterioration of the catalytic converter is suppressed, and the corrosion of the catalyst case is also suppressed.

  According to a second aspect of the present invention, in the cooling mechanism of the catalytic converter according to the first aspect, the cooling water supply unit sprays the cooling water into the gap between the cooling water case and the catalyst case. Features.

  According to this configuration, the cooling water supply unit sprays and supplies the cooling water to the gap between the outer surface of the catalyst case and the cooling water case so that the cooling water is easily vaporized. Easily sucked into exhaust gas and efficiently discharged outside.

  According to a third aspect of the present invention, in the catalytic converter cooling mechanism according to the first or second aspect, the cooling water supply unit uses condensed water condensed by an air conditioner as the cooling water. .

  According to this configuration, since the condensed water condensed in the air conditioner is used as the cooling water, the catalytic converter can be efficiently cooled by reusing the condensed water that would otherwise be discarded. .

  According to a fourth aspect of the present invention, in the cooling mechanism of the catalytic converter according to the first or second aspect, the cooling water supply unit stores the cooling water supplied to the gap between the cooling water case and the catalyst case. It is characterized by having a water storage part.

  According to this configuration, since the cooling water supply unit includes the water storage unit that supplies the cooling water to the gap between the cooling water case and the catalyst case, the cooling water for cooling the catalytic converter can be secured in advance. .

  According to this invention, when the catalyst temperature rises to a preset temperature, the cooling water is supplied from the exhaust inlet side of the catalyst case to the gap between the outer surface of the catalyst case and the cooling water case. The temperature can be reduced efficiently, and thermal deterioration of the catalyst can be prevented.

  The cooling water is sucked into the exhaust gas from the opening that opens close to the exhaust discharge port of the catalyst case and discharged to the outside together with the exhaust gas, thus preventing warm-up particularly during the cold start of the internal combustion engine. Things decrease. Therefore, the function deterioration of the catalytic converter is suppressed, and the corrosion of the catalyst case is also suppressed.

It is a figure explaining the outline of the cooling mechanism of the catalytic converter which concerns on embodiment of this invention. It is the II-II sectional view taken on the line of FIG. It is an enlarged view of the A section of Drawing 1 explaining the outline of the state where the catalytic converter concerning this embodiment is cooled. It is a figure explaining the outline of the cooling mechanism of the catalytic converter which concerns on other embodiment of this invention.

  Next, an embodiment of the present invention will be described with reference to FIGS. In the present embodiment, an example will be described in which the catalytic converter is a catalytic converter disposed in an exhaust system of an internal combustion engine of a vehicle.

  FIG. 1 is a diagram for explaining the outline of the cooling mechanism of the catalytic converter according to the present embodiment, and FIG. 2 is a cross-sectional view taken along the line II-II in FIG. As illustrated, the cooling mechanism 10 includes a catalytic converter 20 and a cooling water supply unit 50 that cools the catalytic converter 20.

  The catalytic converter 20 includes a catalyst case 21, a catalyst carrier 30 accommodated in the catalyst case 21, and a cooling water case 40 that covers the entire catalyst case 21 via the outer surface 28 and the gap S of the catalyst case 21.

  The catalyst case 21 includes a catalyst case body 22, an upstream surface 23 that seals the upstream side of the catalyst case body 22 indicated by an arrow U, and a downstream surface 24 that seals a downstream side of the catalyst case body 22 indicated by an arrow D. It is formed in a cylindrical shape having

  The catalyst case 21 includes an exhaust gas inlet 25 that is an exhaust inlet that projects from the upstream surface 23 toward the upstream U, and an exhaust outlet that projects from the downstream surface 24 toward the downstream D. An exhaust gas outlet 26 is formed.

  The catalyst carrier 30 has an exhaust gas inflow surface 31 and an exhaust gas discharge surface 32, is fitted in the inner surface 27 of the catalyst case 21 and is formed in a cylindrical shape accommodated in the catalyst case 21, and the exhaust gas inflow surface It is formed in a honeycomb shape having cells 33 partitioned by partition walls extending from 31 to the exhaust gas discharge surface 32.

  The catalyst carrier 30 contains a catalyst such as Pt, Pd, or Rh.

  The cooling water case 40 has a cylindrical shape having a cooling water case body 41, an upper wall 42 that seals the upstream side U of the cooling water case body 41, and a lower wall 43 that seals the downstream side D of the cooling water case body 41. Formed.

  The cooling water case 40 is formed with an upstream boss 44 that protrudes from the upper wall 42 toward the upstream U. The upstream boss portion 44 is formed in a cylindrical shape having a side portion 44a and an end portion 44b that is bent inward from the side portion 44a and is continuous.

  The end portion 44b is formed with an introduction portion 45 that protrudes further from the end portion 44b toward the upstream side U and opens to the upstream side U to which the introduction pipe 1 is connected.

  On the other hand, the cooling water case 40 is formed with a downstream boss portion 46 projecting from the lower wall 43 toward the downstream side D. The downstream boss part 46 is formed in a cylindrical shape having a side part 46a and an end part 46b that is bent inward from the side part 46a and is continuous.

  The end portion 46b is formed with an exhaust pipe connection portion 47 that protrudes further from the end portion 46b toward the downstream side D and opens to the downstream side D to which the exhaust pipe 2 is connected.

  In the present embodiment, such a cooling water case 40 covers the entire catalyst case 21 and accommodates the catalyst case 21 through a gap S between the inner surface 40 a and the outer surface 28 of the catalyst case 21.

  Specifically, the end portion of the exhaust gas introduction port 25 of the catalyst case 21 is fitted to the introduction portion 45 formed in the upstream boss portion 44 of the cooling water case 40, and as shown in FIG. The catalyst case 21 is supported on the outer surface 28 of the catalyst case 21 at the exhaust gas discharge port 26 by the support portions 40b formed radially on the inner surface 40a of the cooling water case 40 in the downstream boss portion 46. The catalyst case 21 is accommodated in the cooling water case 40.

  Thereby, the introduction part 45 of the cooling water case 40 and the exhaust gas inlet 25 of the catalyst case 21 are positioned coaxially along the center line C of the catalytic converter 21 and the exhaust gas outlet of the catalyst case 21. 26 and the exhaust pipe connecting portion 47 of the cooling water case 40 are positioned coaxially along the center line C of the catalytic converter 21.

  At this time, the exhaust pipe connecting portion 47 of the cooling water case 40 faces the exhaust gas outlet 26 of the catalyst case 21 toward the upstream side U, and reaches the exhaust gas outlet 26 via the opening 48 having a predetermined interval α. Placed close together.

  The introduction pipe 1 for introducing the exhaust gas G from the internal combustion engine into the catalytic converter 20 is attached to the exhaust gas introduction port 25 of the catalyst case 21 and the introduction portion 45 of the cooling water case 40 in the catalytic converter 20 having the above-described configuration. The exhaust pipe 2 for exhausting the exhaust gas G to the outside is attached to the exhaust pipe connecting portion 47 of the water case 40.

  As a result, the internal combustion engine communicates with the outside through the exhaust system in which the catalytic converter 20 is disposed, and the exhaust gas G from the internal combustion engine is introduced into the catalytic converter 20 through the introduction pipe 1 to be purified. The exhaust gas G is exhausted to the outside through the exhaust pipe 2.

  The cooling water supply unit 50 is a device that cools such a catalytic converter 20, and as shown in FIG. 1, condensation condensed by a water pump 51 and an air conditioner (not shown) that is an air conditioner mounted on a vehicle. A water storage unit 52 for storing water and a control unit 53 are provided as main components.

  The water pump 51 includes an injection nozzle 51a that protrudes into the gap S between the inner surface 40a of the cooling water case 40 and the outer surface 28 of the catalyst case 21 and is fixed to the cooling water case 40, and through the injection nozzle 51a. Then, the condensed water of the air conditioner stored in the water storage section 52 is sprayed on the gap S as cooling water.

  The controller 53 includes a temperature sensor 53a that is attached to the outer surface 28 of the catalyst case 21 and detects the temperature of the catalyst contained in the catalyst carrier 30, and based on the catalyst temperature detected by the temperature sensor 53a, the water pump The spray of the cooling water 51 to the gap S is controlled.

  In the present embodiment, the control unit 53 controls the water pump 51 so that the cooling water is sprayed into the gap S via the injection nozzle 51a when the catalyst temperature rises to a preset high temperature. The program is stored.

  In the present embodiment, for example, when the catalyst temperature rises to 750 ° C., the cooling water is controlled to be sprayed.

  Next, the cooling effect | action of the catalytic converter 20 by the cooling water sprayed from the cooling water supply part 50 which concerns on this Embodiment is demonstrated using FIG.3 and FIG.1.

  FIG. 3 is an enlarged view of a portion A in FIG. 1 for explaining an outline of a state in which the catalytic converter 20 according to the present embodiment is cooled.

  For example, when unburned gas flows into the catalytic converter 20 due to misfire due to a malfunction of the ignition device, or when traveling wind introduced to the outer surface of the catalytic converter relatively decreases due to a steep climb over a long distance In this case, the catalyst temperature rises.

  When the temperature sensor 53 a detects a preset catalyst temperature of 750 ° C., a detection signal is input to the control unit 53. When the detection signal is input to the control unit 53, the water pump 51 causes the condensed water stored in the water storage unit 52 to pass through the injection nozzle 51 a into the cooling water in the gap S between the cooling water case 40 and the catalyst case 21. Spray as.

  As shown in FIG. 3, the cooling water is supplied into the gap S from the upstream U side of the catalytic converter 20 as mist M granulated by applying pressure through the injection nozzle 51a. Is done.

  The mist M supplied in the gap S cools the catalyst built in the catalyst carrier 30 via the catalyst case 21 and lowers the catalyst temperature. The mist M supplied to the gap S is vaporized as the catalyst temperature decreases, and flows down from the upstream U side of the catalytic converter 20 toward the downstream D side.

  On the other hand, the exhaust gas G from the internal combustion engine is introduced into the catalyst carrier 30 accommodated in the catalyst case 21 via the introduction pipe 1, and the introduced exhaust gas G flows down the cell 33 of the catalyst carrier 30.

At this time, harmful substances of the NO _X or the like contained in the exhaust gas G, is reduced by the catalyst incorporated in the catalyst carrier 30, the exhaust gas G is purified.

  The purified exhaust gas G flows into the exhaust pipe 2 attached to the exhaust pipe connection portion 47 of the cooling water case 40 via the exhaust gas discharge port 26 of the catalyst case 21 and is discharged outside.

  At this time, the mist M is exhausted from the opening 48 when the exhaust gas G flows into the exhaust pipe 2 through the opening 48 having a predetermined interval α close to the exhaust gas discharge port 26 of the catalyst case 21. It is sucked into the gas G.

  The mist M sucked into the exhaust gas G is discharged from the exhaust pipe 2 together with the exhaust gas G.

  In the cooling mechanism 10 of the catalytic converter 20 having the above-described configuration, when the catalyst temperature rises and the temperature sensor 53a detects a preset catalyst temperature of 750 ° C., the water pump 51 of the cooling water supply unit 50 opens the injection nozzle 51a. Then, the condensed water of the air conditioner 52 is sprayed into the gap S as cooling water.

  The injection nozzle 51 a supplies mist M obtained by granulating cooling water into the gap S, and the mist M cools the catalyst built in the catalyst carrier 30 via the catalyst case 21. Thereby, catalyst temperature can be reduced efficiently and thermal deterioration of a catalyst can be prevented.

  Moreover, the mist M is sucked into the exhaust gas G from the opening 48 having a predetermined interval α in the vicinity of the exhaust gas discharge port 26 of the catalyst case 21 and discharged from the exhaust pipe 2 together with the exhaust gas G.

  Therefore, since the mist M supplied in the gap S is discharged outside without staying in the gap S, the situation that prevents warm-up particularly during the cold start of the internal combustion engine is reduced. Therefore, the functional deterioration of the catalytic converter 20 is suppressed, and the corrosion of the catalyst case 21 is suppressed.

  In the present embodiment, since the condensed water from the air conditioner is used as the cooling water, the catalytic converter 20 can be efficiently cooled by reusing the condensed water originally discarded. .

  In addition, this invention is not limited to the said embodiment, A various change is possible in the range which does not deviate from the meaning of invention. In the above embodiment, the injection nozzle 51 a protrudes into the gap S between the inner surface 40 a of the cooling water case 40 and the outer surface 28 of the catalyst case 21 in the cooling water case body 41 of the cooling water case 40. As shown in FIG. 4, for example, in the upstream boss portion 44 of the cooling water case 40, a gap between the inner surface 40 a of the cooling water case 40 and the outer surface 28 of the catalyst case 21 is used. It may be fixed to the cooling water case 40 so as to protrude into S.

  In the above embodiment, the case where the condensed water from the air conditioner is used as the cooling water has been described. For example, the catalytic converter 20 that supplies the cooling water only to the water pump 51 of the cooling water supply unit 50 is cooled. A cooling water supply unit 50 may be equipped with a dedicated water storage unit for cooling water.

  Thereby, cooling water for cooling the catalytic converter 20 can be secured in advance.

  In the above embodiment, the case where the cooling water case 40 covers the entire catalyst case 21 has been described. However, the cooling water case 40 may be configured to cover only a part of the catalyst case 21.

  In the above-described embodiment, the case where the spraying of the coolant to the gap S by the water pump 51 is controlled based on the catalyst temperature detected by the temperature sensor 53a that detects the temperature of the catalyst has been described. The catalyst temperature may be estimated based on an exhaust gas sensor that detects the pressure of the exhaust gas, or a pressure sensor that detects the pressure of the exhaust gas. Furthermore, the catalyst temperature may be estimated based on the accelerator opening or the engine speed.

10 Catalytic Converter Cooling Mechanism 20 Catalytic Converter 21 Catalytic Case 25 Exhaust Gas Inlet (Exhaust Inlet)
26 Exhaust gas outlet (exhaust outlet)
28 outer surface 30 catalyst carrier 40 cooling water case 40a inner surface 45 introduction part 47 exhaust pipe connection part 48 opening part 50 cooling water supply part 51 water pump 51a injection nozzle 52 water storage part 53 control part 53a temperature sensor D downstream M mist ( Cooling water)
S Gap U Upstream side

Claims (4)

In the catalytic converter cooling mechanism for cooling the catalytic converter with the catalyst built-in and having a catalyst case having an exhaust inlet and an exhaust outlet,
The catalytic converter is:
A cooling water case that has an opening that opens close to the exhaust outlet of the catalyst case, and that covers a part or all of the catalyst case via an outer surface of the catalyst case and a gap;
A cooling water supply unit is provided in the gap between the cooling water case and the catalyst case to supply cooling water from the exhaust inlet side when the temperature of the catalyst rises to a preset temperature. The catalytic converter cooling mechanism. The cooling water supply unit
The cooling mechanism for a catalytic converter according to claim 1, wherein the cooling water is sprayed into the gap between the cooling water case and the catalyst case. The cooling water supply unit
3. The cooling mechanism for a catalytic converter according to claim 1, wherein condensed water condensed by an air conditioner is used as the cooling water. The cooling water supply unit
The cooling mechanism for a catalytic converter according to claim 1 or 2, further comprising a water storage section for storing cooling water supplied to the gap between the cooling water case and the catalyst case.

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