JP2004116322A - Exhaust gas posttreatment device of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exhaust gas posttreatment device of an internal combustion engine which can facilitate incinerating and regenerating a filter for collecting a particulate, etc., and which can be simplified. <P>SOLUTION: The exhaust gas posttreatment device of the internal combustion engine includes a filter casing 4 having the filter 6 interposed between a casing inlet 402 and a casing outlet 403, a first hole group H1 having a plurality of inlet holes 11 for guiding an exhaust gas in a first direction, a second hole group H2 formed in the filter in a state which does not interfere with the first group and having a plurality of outlet holes 12 for guiding the exhaust gas in a direction different from the first direction, a transmission passage r1 which can transmit the exhaust gas flowing from the inlet 402 to the holes 11 through a wall (w) between the inlet and the outlet and which can flow out to the outlet 403, a bypass passage r2 for exhausting the gas to the outlet c2 from the inlet c1 of the inlet hole from the outlet via a bypass tube 406, and a controller 8 for controlling a control valve 7 in response to an exhaust pressure pg or a filter temperature. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an exhaust aftertreatment device for an internal combustion engine that collects particulates and the like from exhaust gas of an internal combustion engine, and more particularly, to an exhaust posttreatment device for an internal combustion engine that properly burns and regenerates particulates collected by a filter. .
[0002]
[Prior art]
In the exhaust gas of an internal combustion engine, in particular, a diesel engine, particulates having nuclei such as carbon fine particles are mixed therein, and in order to collect the particulates without releasing them to the atmosphere, the particulates are collected on an exhaust gas flow path of the diesel engine. Is equipped with a particulate filter. When the amount of accumulated particulates increases, the particulate filter must be incinerated and regenerated. The particulates here can be oxidized with oxygen at a high temperature of about 600 ° C., but the operating range for maintaining the incineration temperature is relatively short, and the period to reach such an operating range is relatively short. Has become.
Here, the particulates are composed of an INSOL component (insoluble component) containing soot as a main component and an SOF component (soluble organic component) containing unburned fuel, lubricating oil, sulfuric acid mist and the like as main components.
[0003]
JP-A-5-222918 (Patent Document 1) discloses that an exhaust pipe 12 of a diesel engine 11 is provided with a DPF 13 having a regeneration heater 14 and a burner 16, and the electronic control unit 25 includes the heater 14 and the burner 16. A technique for controlling is disclosed. In Patent Document 1, when starting regeneration in the operating state of the engine 11, the heater 16 is energized to perform regeneration of the DPF 13 for a predetermined time. When the engine 11 is stopped during this regeneration operation, a battery For protection, the power supply to the heater 14 is cut off, and the burner 16 is ignited to complete a predetermined regeneration operation.
[0004]
Japanese Patent Application Laid-Open No. 2001-73743 (Patent Document 2) discloses that, when performing filter regeneration, the opening degree control valve 18 is controlled so that the exhaust passage 10 is slightly opened and the bypass passage 14 is almost fully opened. A technique is disclosed in which part of exhaust gas during engine operation is guided to a filter 12 and the heat consumed by the burner device 20 is reduced by using exhaust heat.
[0005]
[Patent Document 1]
JP-A-5-222918 [Patent Document 2]
JP 2001-73743 A
[Problems to be solved by the invention]
As in the above-mentioned patent documents, in the method of forcibly heating the filter and burning and removing the accumulated particulates, there is a concern that the filter may be melted by the particulate accumulation conditions and temperature conditions, This type of forced regeneration means has a problem in that the filter must be maintained at a high temperature and fuel economy is likely to deteriorate. In addition, there is a method in which exhaust gas or air flows backward from the downstream part of the filter, and the accumulated particulates are discharged from the upstream part of the filter and collected.However, in this case, a large system mounting space is required. is there.
[0007]
As described above, none of the essential regeneration means has been established when using diesel particulates.
The present invention provides an exhaust aftertreatment device for an internal combustion engine that can simplify the incineration regeneration process of a filter that collects particulates and the like from the exhaust gas of the internal combustion engine and achieves simplification of the device based on the above-described problem. The purpose is to:
[0008]
[Means for Solving the Problems]
Means for Solving the Problems To achieve the above object, the invention according to claim 1 provides a filter casing in which a filter for trapping particulates in exhaust gas is interposed between a casing inlet and a casing outlet, and the filter casing, A first group of holes formed in parallel and formed of a plurality of inflow holes for guiding exhaust gas in a first direction; and a filter formed in the filter so as not to interfere with the first group of holes. A second hole group formed of a plurality of outflow holes for guiding exhaust gas in a direction different from the one direction, and an exhaust gas flowing into the inflow hole from the casing inlet penetrates a wall portion between the inflow hole and the outflow hole to outflow hole. A permeation path through which the exhaust gas can reach the outlet from the inlet of the inflow hole, and a bypass path through which the exhaust gas is discharged from the casing outlet via a bypass pipe having a control valve; Depending on the exhaust gas pressure or the filter temperature at the mouth, characterized in that a control means for controlling the control valve.
By opening the control valve in the operating range where the exhaust pressure increases or the operating temperature of the filter is low, exhaust gas is discharged from the bypass passage, so that particulates do not excessively accumulate on the filter, and regeneration is performed. The filter temperature during combustion does not rise excessively, and a decrease in durability due to erosion of the filter can be prevented.
[0009]
According to a second aspect of the present invention, in the exhaust aftertreatment device for an internal combustion engine according to the first aspect, the control means controls to open the control valve when the exhaust pressure exceeds the excessive deposition determination pressure. And
As described above, the filter collects the particulates of the exhaust gas flowing into the inflow hole from the casing inlet, and when the amount of accumulation reaches an excessive amount of accumulation, the control means opens the control valve and discharges the exhaust gas from the bypass passage. In addition, the particulates do not excessively accumulate on the filter, the filter temperature during regeneration combustion does not excessively increase, and a decrease in durability due to erosion of the filter can be prevented. In addition, a bypass path is formed in the filter casing, and the device can be made compact.
[0010]
According to a third aspect of the present invention, in the exhaust aftertreatment device for an internal combustion engine according to the first aspect, a catalyst is supported on at least an inner wall of the outflow hole.
As described above, at least the exhaust gas passing through the inflow hole is promoted by the catalyst in the inflow hole, so that the purification reaction can be promoted.
Preferably, the catalyst is an oxidation catalyst. In this case, the SOF component in the particulates can be oxidized and purified, and the INSOL component in the particulates can be oxidized and burned by NO2 generated by the oxidation catalyst.
[0011]
According to a fourth aspect of the present invention, in the exhaust aftertreatment device for an internal combustion engine according to the first aspect, a catalyst is supported on inner walls of the inflow hole and the outflow hole, and the bypass passage is provided with the exhaust gas passing through the bypass pipe. It is characterized in that it is formed so as to be discharged from the casing outlet after passing through the outflow holes of the hole group.
In this case, when the control means opens the control valve when the accumulation amount of the filter reaches the excessive accumulation amount, the exhaust gas passes through the inflow path, the bypass pipe, and the outflow path in this order, and is discharged from the casing outlet. During this time, the frequency of contact of the exhaust gas with the catalysts in the inflow passage and the outflow passage increases, so that the exhaust gas purification process and the burning of particulates can be sufficiently promoted.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 shows an exhaust aftertreatment device 1 for an internal combustion engine to which the present invention is applied as one embodiment. The exhaust aftertreatment device 1 is mounted on an exhaust passage R extending from a combustion chamber (not shown) of the engine 2.
The exhaust path R is formed by sequentially connecting the exhaust after-treatment device 1 in the middle of the exhaust pipes 3u and 3d forming the main part thereof, and the muffler 5 downstream thereof.
[0013]
The exhaust aftertreatment device 1 in the middle of the exhaust pipe 3 includes a metal cylindrical filter casing (hereinafter simply referred to as a casing) 4. The casing 4 accommodates a particulate filter (hereinafter simply referred to as a filter) 6 for collecting particulates in the exhaust gas in the bulging portion 401, and a casing inlet 402 and a casing outlet 403 are provided on the outer peripheral portion of the bulging portion 401. The bypass pipe 406 is integrally formed along the side wall of the bulging portion 401.
As shown in FIGS. 1 to 3, the bulging portion 401 of the casing 4 has a rectangular box shape, an inflow pipe portion 404 extends from one end of an upper wall thereof, and an outflow pipe portion 405 extends from a side vertical wall. And the bypass pipe 406 is formed to extend from the other end of the lower wall.
[0014]
The inflow pipe section 404 is integrally connected to the upstream exhaust pipe 3u in a communicating state by a fastening means (not shown) so that exhaust gas from the exhaust pipe 3u can be introduced into the inflow space e1 above the bulging portion. The outflow pipe portion 405 is integrally connected to the downstream exhaust pipe 3d in a communicating state by fastening means (not shown), and the exhaust gas in the outflow space e2 on the side (lower side in FIG. 2) of the bulging portion 401 is exhausted on the downstream side. It can flow out to the pipe 3d. The bypass pipe 406 is integrally connected in communication with an extension bypass pipe (having a cross section similar to that of the bypass pipe 406) 407 provided with the control valve 7 by fastening means (not shown), and a lower portion of the bulging portion 401 (see FIG. 3). The exhaust gas in the short circuit space e3) can flow out to the extension bypass pipe 407. The extension end of the extension bypass pipe 407 is integrally connected to the joint q of the outflow pipe section 405 in a communicating state by a fastening means (not shown), and the exhaust gas in the short circuit space e3 is connected to the downstream outflow pipe section 405 and the exhaust pipe 3d. Can be exhausted.
[0015]
The control valve 7 is a proportional solenoid valve, and upon receiving a valve drive signal from a controller 8 as a control means, drives a butterfly valve (not shown) that opens and closes the extension bypass pipe 407 and changes the opening of the passage cross section from the fully closed state. It is formed so as to be adjustable between full open and closed.
The filter 6 is made of ceramic, that is, made of cordierite containing Mg, Al, and Si as main components, has a block shape as a whole, and has a number of exhaust gas passages formed therein.
That is, the filter 6 has a plurality of inflow holes 11 formed so as to extend in the vertical direction Z (see FIG. 3) which is the first direction, and is arranged in parallel in the longitudinal direction X with an interval a therebetween. The first hole group H1 is formed sequentially.
[0016]
Here, each inflow hole 11 guides the exhaust gas from the inflow port c1 formed in the upper wall section 601 of the filter 6 to the outflow port c2 formed in the lower wall section 602 and the short circuit space e3. The exhaust gas is guided in a first direction.
Further, the filter 6 has an outflow hole 12 between each inflow hole 11 adjacent to each other. Here, the wall portion w between the outflow hole 12 and each adjacent inflow hole 11 is set to a predetermined thickness t so that the exhaust gas can pass therethrough.
[0017]
Each outflow hole 12 is covered by left and right side walls 603 and 604 and upper and lower side walls 601 and 602 of the filter 6, and communicates with the outflow space e2 through a rectangular hole d1 formed in the left side wall 603. That is, each outflow hole 12 guides the exhaust gas passing through the wall portion w from each adjacent inflow hole 11 to the outflow space e2 through the rectangular hole d1 of the left side wall portion 603. The exhaust gas is guided in two directions.
As described above, the first hole group H1 including the respective inlet holes 11 for guiding the exhaust gas in the first direction and the second hole group H2 including the respective outlet holes 12 for guiding the exhaust gas in the second direction different from the first direction. Are formed on the filter 6 with a predetermined distance t apart and not interfering with each other.
[0018]
An oxidation catalyst pr is carried on the inner walls of the inflow hole 11 and the outflow hole 12 of the filter 6.
The oxidation catalyst pr oxidizes nitrogen monoxide (NO) in the exhaust gas discharged from the engine 2 with oxygen O ₂ to generate highly active nitrogen dioxide (NO ₂ ), and outputs highly active nitrogen dioxide (NO ₂ ). And promotes the oxidation and incineration of the collected particulates. The controller 8 serving as control means detects the engine speed Ne from the exhaust pressure pg of the pressure sensor 13 attached to the casing inlet 402 and the engine speed sensor 14.
[0019]
Then, the average value of the exhaust pressure pgn at the predetermined engine speed Ne1 is sequentially updated. Then, the drive output DUn of the control valve 7 corresponding to the latest exhaust pressure pgn is derived from the drive output calculation map m1 in FIG. 5, and the control valve 7 is driven with the drive output DUn. The drive output calculation map m1 sets the valve fully closed output DU = 0% (non-operating) when the exhaust pressure is pg0 or less, and sets the valve fully open output DU = 100% when the exhaust pressure is pg1 or more. Is set so that the valve opening output DU increases at a predetermined ratio according to the increase in the exhaust pressure.
In such an exhaust after-treatment device 1, when the engine (not shown) is driven, the controller 8 takes in the engine speed Ne and the exhaust pressure pgn, sequentially updates the average value of the exhaust pressure pgn, and corresponds to the latest exhaust pressure pgn. The drive output DUn is derived, and the control valve 7 is driven with the drive output DUn.
[0020]
At this time, when the exhaust pressure pgn is low and the valve fully closed output DU = 0% (non-operation), the bypass pipe 7b, that is, the bypass passage r2 is closed. As a result, the exhaust gas flowing into the inflow hole 11 from the casing inlet 402 passes through the wall w between the inflow hole 11 and the outflow hole 12, and flows through the permeation path r1 through which the rectangular hole d1 of the outflow hole 12 can flow out to the casing outlet 403. Form. At this time, the particulates in the exhaust gas are collected on the wall surface of the inflow hole 11. Further, when the exhaust gas temperature reaches a relatively high operating range, the INSOL component in the particulates on the wall surface of the inflow hole 11 is oxidized and incinerated at a relatively low temperature by NO2 generated by the oxidation catalyst pr, and the filter regeneration processing is performed. Is done. Further, the SOF component in the particulates is oxidized and purified by Pr by the oxidation catalyst.
[0021]
On the other hand, the operation in which the oxidizing combustion of the particulates on the wall surface of the inflow hole 11 does not proceed continues, the accumulation amount of the particulates increases, and every time the average value of the exhaust pressure pgn is updated, the latest exhaust pressure pgn is exhausted. Assume that the pressure exceeds pg0.
In this case, the controller 8 derives the latest valve opening output DUn corresponding to the latest exhaust pressure pgn, drives the control valve 7 with the same value, and switches and holds the control valve 7 to the valve opening corresponding to the output value. As a result, the bypass pipe 7b, that is, the bypass path r2 is opened by a predetermined amount or fully opened, the exhaust gas flowing into the inlet hole 11 from the casing inlet 402 reaches the outlet c2 from the inlet c1, and the short-circuit space e3 has a predetermined opening degree. It can flow out to the casing outlet 403 via the control valve 7 and the bypass pipe 7. As described above, a part of the exhaust gas passes through the bypass path r2, the increase of the particulates on the wall surface of the inflow hole 11 is restricted, excessive accumulation can be prevented, and an excessive rise in filter temperature during combustion can be prevented. The durability of the exhaust after-treatment device 1 can be ensured. Moreover, when a part of the exhaust gas passes through the inflow hole 11, the reaction of the HC, CO and SOF components can be promoted by the action of the oxidation catalyst pr, and the exhaust gas purifying function can be exhibited.
[0022]
In the above-described embodiment, the control valve 7 is gradually opened when the exhaust pressure Pgn at the filter inlet exceeds the exhaust pressure Pgo. However, the present invention is not limited to this. For example, when the exhaust pressure at the filter inlet increases at the same engine speed Neb, or when the filter temperature is equal to or lower than the set temperature for an operation time equal to or longer than a predetermined time, or when the frequency at which the filter temperature is equal to or lower than the set temperature is high, The opening of the control valve may be controlled, or the opening may be controlled to be large according to the degree of increase of the exhaust pressure and the filter temperature.
[0023]
6 and 7 show an exhaust after-treatment device 1a as another embodiment of the present invention.
The exhaust after-treatment device 1a here has almost the same configuration as the exhaust after-treatment device 1 of FIG. 1 except that the configurations of the inflow channel 11a, the outflow channel 12a, and the bypass channel r2a are different. The description will be omitted, and the differences will be mainly described. Note that the same members are denoted by reference numeral a.
[0024]
The filter 6a of the exhaust after-treatment device 1a has a rectangular block shape and the inside is vertically divided into layers, and the first hole group H1 and the second hole group H2 are arranged alternately in the vertical direction. For this reason, the first hole group H1 and the second hole group H2 are formed on the filter 6 in a vertically stacked state without interfering with each other. The upper and lower walls of the filter 6a are sandwiched between the bulging portions 401a of the casing from above and below via a sealing material. A space e3 and a return space e4 are formed.
[0025]
The filter 6a is formed in a state where a plurality of inflow holes 11a formed so as to guide exhaust gas in the longitudinal direction X are arranged in parallel with an interval j therebetween, and a first hole group H1 is formed. Each inflow hole 11a guides the exhaust gas from the inflow port c1 facing the inflow space e1 on the casing inlet 402 side to the outflow port c2 facing the short circuit space e3, that is, guides the exhaust gas in the first direction.
[0026]
Further, as shown in FIG. 7, the filter 6a has a plurality of outflow holes 12a arranged in parallel on the upper and lower sides of the first hole group H1. Here, as shown in FIG. 6, each of the outflow holes 12a guides the exhaust gas from the inflow port d2 facing the return space e4 to the outflow space e2, that is, guides the exhaust gas in the second direction.
The wall wa between each of the outflow holes 12a and each of the inflow holes 11a vertically adjacent to each other is set to a predetermined thickness ta so that the exhaust gas can pass therethrough. Here, the oxidation catalyst pr is carried on the inner walls of the inflow hole 11 and the outflow hole 12 of the filter 6.
[0027]
A return bypass pipe 407a is integrally attached near the side wall of the bulging portion 401a of the casing. The return bypass pipe 407a includes a control valve 7a on the way, and is formed so as to return the exhaust gas in the short-circuit space e3 to the return space e4.
The control valve 7a is formed similarly to the control valve 7. The controller 8a, which is a control means, has the same control function as the controller 8.
The exhaust post-processing device 1a drives the control valve 7 with a drive output DUn corresponding to the engine speed Ne and the exhaust pressure pgn, similarly to the exhaust post-processing device 1.
[0028]
At this time, when the exhaust pressure pgn is low and the valve fully closed output DU = 0% (non-operating), the return bypass pipe 407a, that is, the bypass path r2 is closed, and the exhaust gas flowing into the inflow hole 11a flows into the inflow hole 11a. Through the wall wa between the outlet hole 12a and the outlet hole 12a, and can flow out to the casing outlet 403 through the outlet space e2. At this time, the particulates in the exhaust gas are collected on the wall surface of the inlet hole 11a, and the exhaust gas is exhausted. When the temperature reaches a relatively high operating range, the INSOL component in the particulates is oxidized and burned at a relatively low temperature by NO2 generated by the oxidation catalyst pr, and the filter is regenerated. Further, the SOF component in the particulate is oxidized and purified by the oxidation catalyst Pr.
[0029]
On the other hand, it is assumed that the accumulation amount of the particulates in the inflow hole 11a increases and the latest exhaust pressure pgn exceeds the exhaust pressure pg0.
In this case, the controller 8a drives the control valve 7a with the valve opening output DUn corresponding to the exhaust pressure pgn, and switches the control valve 7a to a valve opening degree corresponding to the output value. As a result, the return bypass pipe 407a, that is, the bypass path r2 is opened by a predetermined amount, and the exhaust gas in the inflow hole 11a can flow out to the casing outlet 403 via the return bypass pipe 407a, the short circuit space e3, the outflow hole 12a, and the outflow space e2. In this way, a part or all of the exhaust gas passes through the bypass passage r2, the increase in the particulates in the inflow hole 11a is regulated, excessive deposition can be prevented, and an excessive rise in filter temperature during combustion can be prevented. The durability of the exhaust after-treatment device 1a can be ensured. In particular, when a part of the exhaust gas passes through the inflow hole 11a and the outflow hole 12a, the frequency of contact with the oxidation catalyst pr is sufficiently increased, and the purification reaction of HC, CO, and SOF components in the exhaust gas is sufficiently performed. And the exhaust gas purifying function can be sufficiently exhibited.
[0030]
6 and 7, the inflow space e1 facing the casing inlet 402a may have a sufficient capacity, and may have a silencing function. In this case, there is no need to provide a separate muffler, and there is an advantage that the pressure loss of the exhaust system can be further reduced and the exhaust system can be simplified.
[0031]
【The invention's effect】
As described above, according to the first aspect of the present invention, the filter collects the particulates of the exhaust gas flowing into the inflow hole from the casing inlet, and controls the control valve according to the exhaust pressure at the casing inlet or the filter temperature. By increasing the exhaust pressure or opening the control valve in the operating range where the filter temperature is low, the particulates do not excessively accumulate on the filter and the filter temperature during combustion by self-ignition increases excessively. Without this, it is possible to prevent the durability from being lowered due to the melting of the filter.
[0032]
According to the second aspect of the present invention, the filter collects the particulates of the exhaust gas flowing from the casing inlet into the inflow hole, and when the amount of the accumulated gas reaches the excessive amount of accumulation, the control means opens the control valve to pass the exhaust gas to the bypass passage. Since the particulates are more discharged, the particulates do not excessively accumulate on the filter, the filter temperature during regeneration and combustion does not excessively increase, and a decrease in durability due to melting damage of the filter can be prevented. In addition, a bypass path is formed in the filter casing, and the device can be made compact.
[0033]
According to the third aspect of the present invention, the purification reaction of the exhaust gas passing through the inflow hole is promoted by the catalyst in the inflow hole, so that the exhaust gas purification can be promoted.
[0034]
According to the fourth aspect of the present invention, since the catalyst is carried on the inner walls of the inflow hole and the outflow hole, the exhaust gas passes through the inflow path, the bypass pipe, and the outflow path in this order, and is discharged from the casing outlet. The frequency of contact of the exhaust gas with the catalyst in the inflow passage and the outflow passage increases, and the exhaust gas purification processing and the burning of particulates can be sufficiently promoted.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of an exhaust aftertreatment device for an internal combustion engine as one embodiment of the present invention.
FIG. 2 is a plan sectional view of the exhaust after-treatment device of FIG.
FIG. 3 is a side sectional view of the exhaust after-treatment device of FIG. 1;
FIG. 4 is an explanatory view showing passage of exhaust gas through a filter used by the exhaust after-treatment device of FIG.
FIG. 5 is a characteristic diagram of a control valve opening degree setting map used in the regeneration control of the exhaust after-treatment device in FIG. 1;
FIG. 6 is a plan sectional view of an exhaust after-treatment device according to another embodiment of the present invention.
FIG. 7 is a side sectional view of the exhaust after-treatment device of FIG. 6;
[Explanation of symbols]
4 Filter Casing 402 Casing Inlet 403 Casing Outlet 407 Bypass Pipe 6 Filter 7 Control Valve 11 Inlet Hole 12 Outlet Hole H1 First Hole Group H2 Second Hole Group c1 Inlet c2 Outlet r1 Permeation Path r2 Bypass Path w Wall pg Exhaust Atmospheric pressure pgα Deposition judgment pressure

Claims (4)

A filter casing in which a filter for collecting particulates in exhaust gas is interposed between a casing inlet and a casing outlet,
A first hole group formed of a plurality of inflow holes formed in the filter and arranged in parallel with each other to guide exhaust gas in a first direction;
A second hole group formed of a plurality of outflow holes formed in the filter so as not to interfere with the first hole group and arranged in parallel with each other and guiding exhaust gas in a direction different from the first direction;
A permeation path through which exhaust gas flowing into the inflow hole from the casing inlet can pass through the wall between the inflow hole and the outflow hole and flow out to the casing outlet from the outflow hole,
A bypass passage through which the exhaust gas reaching the outlet from the inlet of the inlet hole is discharged from the casing outlet through a bypass pipe having a control valve;
Control means for controlling the control valve according to the exhaust pressure at the casing inlet or the filter temperature. 2. The exhaust after-treatment device for an internal combustion engine according to claim 1, wherein said control means controls to open said control valve when the exhaust pressure exceeds an excessive deposition determination pressure. Processing equipment. The exhaust aftertreatment device for an internal combustion engine according to claim 1,
An exhaust aftertreatment device for an internal combustion engine, wherein a catalyst is carried on at least an inner wall of the inflow hole. The exhaust aftertreatment device for an internal combustion engine according to claim 1,
A catalyst is supported on inner walls of the inflow hole and the outflow hole,
The exhaust post-treatment device for an internal combustion engine, wherein the bypass passage is formed such that exhaust gas passing through the bypass pipe passes through the outflow holes of the second group of holes and is then discharged from the casing outlet. .

Images