JP7232750B2 - Exhaust purification device - Google Patents

Description

The present invention relates to an exhaust purification device. More specifically, the present invention provides an exhaust purification unit such as an exhaust purification catalyst and/or filter regardless of whether the rotational speed of the internal combustion engine is high or low (that is, regardless of the flow velocity of the exhaust discharged from the internal combustion engine). The present invention relates to an exhaust purification device capable of sufficiently uniforming the impact of exhaust gas on the front end surface of the exhaust gas.

Exhaust gas emitted from internal combustion engines such as gasoline engines and diesel engines contains particulate matter (e.g., carbon monoxide (CO), unburned hydrocarbons (HC: HydroCarbon), nitrogen oxides (NOx) and soot). PM) and other specific substances are included. Therefore, from the viewpoint of global environmental protection, for example, exhaust purification catalysts such as oxidation catalysts (OC: Oxidation Catalyst), three-way catalysts (TWC: Three-Way Catalyst) and selective catalytic reduction denitration equipment (SCR: Selective Catalytic Reduction), and An exhaust treatment device including an exhaust treatment unit such as a filter such as a gasoline particulate filter (GPF: Gasoline Particulate Filter) and a diesel particulate filter (DPF: Diesel Particulate Filter) that collects PM is interposed in the exhaust flow path of the internal combustion engine. It is widely practiced to remove these specific substances by wearing them.

By the way, if the above-described exhaust purification catalysts such as OC, TWC, and SCR have not reached a predetermined activation temperature, the exhaust purification catalysts cannot exhibit a sufficient catalytic action, and the exhaust purification function deteriorates. . For example, when the temperature of the exhaust purification catalyst is not sufficiently high, such as when the internal combustion engine is started in the cold (cold start), or when the frequency of operation of the internal combustion engine is low in a hybrid vehicle, etc. Since the temperature of the purification catalyst has not reached the activation temperature, it may become difficult to exhibit the desired exhaust gas purification function. Therefore, from the viewpoint of environmental protection, the exhaust purification catalyst is arranged in the immediate vicinity of the exhaust port of the internal combustion engine, the temperature of the exhaust purification catalyst quickly reaches the activation temperature, and the desired exhaust purification function is exhibited. is preferred.

However, the space around the internal combustion engine that can be occupied by the exhaust purification device is naturally limited. In many cases, the purification catalyst is arranged so that the axial direction thereof is substantially perpendicular. That is, the exhaust path between the exhaust port of the internal combustion engine and the exhaust purification catalyst often has a portion bent at a substantially right angle (bent portion). It is known that the fluid flowing through such a curved exhaust path tends to flow unevenly along the wall surface having the larger radius of curvature. Therefore, the exhaust gas does not uniformly hit the upstream end face (front end face) of the exhaust purification catalyst, which may lead to problems such as difficulty in uniformly increasing the temperature of the exhaust purification catalyst.

Also, in filters such as the GPF and DPF described above, if exhaust air hits the front end face of the filter unevenly, it may lead to problems such as local clogging of the filter. Therefore, in this technical field, by providing a structure for swirling the exhaust immediately before (in the vicinity of the upstream side) an exhaust purification unit such as an exhaust purification catalyst and/or a filter, the exhaust is uniformly applied to the front end surface of the exhaust purification unit. Various techniques have been proposed to make it possible.

For example, it has been proposed to provide an arc-shaped recess in a collecting pipe of an exhaust manifold configured to guide exhaust from the cylinder side at one end of a multi-cylinder engine to an exhaust purification device located below (see, for example, Patent See Reference 1). According to this, by bending the flow of the exhaust gas at the recessed portion and swirling the exhaust gas on the downstream side of the recessed portion, the flow of the exhaust gas is made uniform and the uniformity of the contact of the exhaust gas with the catalyst in the exhaust purification device is improved. can be improved. However, when the rotation speed of the internal combustion engine is high, the flow rate of the exhaust gas is large and the flow velocity of the exhaust gas bent in the recess is high. There is a risk that the contact of the exhaust gas with the catalyst may become uneven.

Further, an exhaust pipe having an exhaust pipe main body extending curvedly toward the upper end of the cylindrical exhaust purification catalyst device provided with the exhaust purification catalyst, and an exhaust pipe introducing portion connecting the exhaust pipe main body and the upper end. In the structure, it is proposed that the center of the exhaust inlet of the exhaust pipe main body is offset from the central axis of the exhaust purification catalytic device, and that the exhaust outlet of the exhaust pipe main body is connected to the outer peripheral side of the exhaust pipe introduction part. (See Patent Document 2, for example). According to this, by swirling the exhaust gas in the space between the exhaust pipe introduction portion and the upper end face of the exhaust gas purification catalyst device, it is possible to sufficiently suppress the uneven flow of the exhaust gas and quickly raise the temperature of the exhaust gas purification catalyst. can. However, in this case also, when the rotational speed of the internal combustion engine is high, the flow rate of the exhaust gas is large, and the flow velocity of the exhaust gas flowing from the exhaust pipe main body portion to the exhaust pipe introduction portion is high. There is a possibility that the exhaust gas may reach the catalyst without being able to swivel freely, and the contact of the exhaust gas with the catalyst may become uneven.

As described above, in the exhaust purification device according to the prior art, the exhaust purification catalyst and/or filter are used regardless of whether the rotation speed of the internal combustion engine is high or low (that is, regardless of the flow velocity of the exhaust gas discharged from the internal combustion engine). A technique capable of sufficiently uniforming the impact of the exhaust gas on the front end surface of the exhaust purification unit has not yet been established.

Japanese Patent No. 6500967 Japanese Patent No. 6537606

As described above, in this technical field, regardless of whether the rotational speed of the internal combustion engine is high or low (that is, regardless of the flow velocity of the exhaust discharged from the internal combustion engine), exhaust purification catalysts and/or filters, etc. There is a demand for an exhaust purification device capable of sufficiently uniforming the impact of exhaust air on the front end face of the unit.

In view of the above problems, an exhaust purification device according to the present invention (hereinafter sometimes referred to as "the present invention device") is an exhaust purification device that includes an exhaust purification section and an exhaust supply section. The exhaust purification unit includes an exhaust purification unit, which is a columnar member for purifying the exhaust emitted from the internal combustion engine, and a case, which is a tubular member enclosing the exhaust purification unit. The exhaust gas supply unit is connected to the upstream end of the case of the exhaust gas purification unit and defines a flow path for supplying the exhaust gas to the exhaust gas purification unit.

The exhaust supply section includes first to third sections enumerated below. The first part is a member that defines a first space that is an annular flow path that surrounds a first straight line that includes the axis of the exhaust purification unit. The second part is a member that is connected to the upstream end of the first part and defines the second space, which is a flow path for supplying the exhaust gas to the first space. The third part is disposed between the upstream end of the case of the exhaust purification unit and the first part, closes the upstream end of the case, and supplies exhaust gas from the first space to the exhaust purification unit. It is a member that defines a third space, which is a flow path that flows through.

Further, a slit extending along the first space and connecting the first space and the third space is formed on the third part side of the first part. In addition, the first part is configured such that the cross-sectional area of the first space decreases from the upstream side to the downstream side. Details of the cross-sectional area of the first space will be described later.

As described above, in the device of the present invention, exhaust gas is purified through the slit extending along the annular first space surrounding the straight line including the axis of the exhaust gas purification unit and connecting the first space and the third space. Exhaust air is supplied to the unit. Since the cross-sectional area of the first space is configured to decrease from the upstream side to the downstream side, the flow velocity distribution of the exhaust gas flowing from the first space to the third space through the slit is made uniform. Therefore, according to the device of the present invention, regardless of whether the rotational speed of the internal combustion engine is high or low (that is, regardless of the flow velocity of the exhaust gas discharged from the internal combustion engine), the exhaust gas is sufficiently prevented from hitting the front end face of the exhaust purification unit. can be homogenized to

Other objects, features and attendant advantages of the present invention will be readily understood from the description of each embodiment of the present invention described with reference to the following drawings.

1 is a schematic perspective view showing an example of the configuration of an exhaust purification device (first device) according to a first embodiment of the present invention; FIG. 1. It is a schematic diagram which illustrates the state which observed the 1st apparatus cut|disconnected by the plane containing the 1st straight line which is a straight line containing the axis|shaft of the exhaust gas purification unit which the 1st apparatus illustrated in FIG. 1 is provided from the cut surface side. FIG. 10 is a schematic perspective view showing an example of the configuration of Modified Example 2-1 of the exhaust emission control device (second device) according to the second embodiment of the present invention; FIG. 4 is a schematic perspective view of the second device according to modification 2-1 illustrated in FIG. 3 when observed from an angle different from that in FIG. 3; FIG. 3 illustrates a state in which the second device cut by a plane including a first straight line, which is a straight line including the axis of the exhaust purification unit provided in the second device according to modification 2-1 illustrated in FIG. 3, is observed from the cut surface side. It is a schematic diagram. FIG. 4 is a schematic cross-sectional view showing how at least part of the exhaust gas flowing from the first space to the third space through the slit in the first device flows from the slit toward the first straight line L1. FIG. 11 is a schematic diagram illustrating a state of observing the second device cut by a plane including the first straight line, which is a straight line including the axis of the exhaust gas purification unit provided in the second device according to modification 2-2, from the cut surface side. FIG. 11 is a schematic diagram illustrating a state of observing the second device cut by a plane including the first straight line, which is a straight line including the axis of the exhaust gas purification unit provided in the second device according to modification 2-3, from the cut surface side. FIG. 10 is a schematic diagram illustrating a state of observing the second device cut along a plane including the first straight line, which is a straight line including the axis of the exhaust purification unit provided in the second device according to modification 2-4, from the cut surface side. FIG. 10 is a schematic diagram illustrating a state in which a cut surface of the second device according to modification 2-4 illustrated in FIG. 9 is observed from the side of the exhaust gas purification unit at a predetermined elevation angle; FIG. 11 is a schematic diagram illustrating a state in which the second device according to modification 2-4 illustrated in FIGS. 9 and 10 is observed from the first section side in a direction parallel to the first straight line; FIG. 11 is a schematic diagram illustrating a state of observing a third device cut by a plane including a first straight line, which is a straight line including an axis of an exhaust gas purification unit provided in a second device according to modification 2-5, from a cut surface side.

<<1st Embodiment>>
Hereinafter, an exhaust purification device (hereinafter sometimes referred to as "first device") according to a first embodiment of the present invention will be described with reference to the drawings.

<composition>
The first device is an exhaust purification device that includes an exhaust purification section and an exhaust supply section. The exhaust purification unit includes an exhaust purification unit, which is a columnar member for purifying the exhaust emitted from the internal combustion engine, and a case, which is a tubular member enclosing the exhaust purification unit. Specific examples of the exhaust treatment unit include, for example, an oxidation catalyst (OC), a three-way catalyst (TWC), an exhaust purification catalyst such as a selective catalyst reduction denitrification device (SCR), a gasoline particulate filter (GPF) for collecting PM, and Filters, such as a diesel particulate filter (DPF), etc. can be mentioned.

The specific configuration of the case is as long as it can accommodate the exhaust purification unit inside, guide the exhaust emitted from the internal combustion engine to the exhaust purification unit, and withstand the usage environment and usage conditions as an exhaust purification device. It is not particularly limited. Specifically, the case may be composed of a tubular member (pipe) made of a metal material such as stainless steel, or may be formed by a method of stacking a plurality of press-molded members (so-called “Monaka method”). may be configured.

A specific method for fixing the exhaust gas purification unit inside the case is to fix the exhaust gas purification unit at a predetermined position inside the case and to withstand the environment and conditions of use as an exhaust gas purification device. It is not particularly limited as long as As a specific example of such a method, for example, a holding member (mat), which is a cushioning material made of a material having sufficient heat resistance and capable of exerting a restoring force as repulsion against compression, is used in the exhaust purification unit. and the case, and the exhaust purification unit is held and fixed at a predetermined position inside the case by the restoring force of the holding member.

As described above, the holding member (mat) is sandwiched between the exhaust purification unit and the case, and the method for holding the exhaust purification unit at a predetermined position inside the case by the restoring force of the holding member is particularly limited. not. Specific examples of such techniques include a press-fitting method and a sizing method. The press-fitting method is, for example, an assembly in which a holding member is wound or fixed around at least a partial region of the outer peripheral surface of the exhaust gas purification unit, and is placed at a predetermined position inside the case while the holding member is compressed. This is a construction method in which the exhaust purification unit is held by the restoring force of the holding member by (tightly) inserting it. On the other hand, the sizing method is, for example, an assembly in which a holding member is wound or fixed on at least a partial region of the outer peripheral surface of the exhaust gas purification unit, and the holding member is not substantially compressed. After inserting (loosely) into a predetermined position inside the case, at least a part of the region facing the holding member of the case is subjected to a diameter reduction process to reduce the diameter to a predetermined diameter, so that the restoring force of the holding member causes the exhaust gas purification unit. It is a construction method that maintains

Specific examples of materials constituting the above holding member include inorganic fibers such as alumina-based fibers and alumina-silica-based fibers, and inorganic fibers added with a resin as a binder. can be done. Specific examples of the resin used as the binder include acrylic rubber, nitrile rubber, polyvinyl alcohol and acrylic resin.

The exhaust gas supply unit is connected to the upstream end of the case of the exhaust gas purification unit and defines a flow path for supplying the exhaust gas to the exhaust gas purification unit. The specific configuration of the exhaust gas supply unit satisfies the requirements described later, guides the exhaust gas emitted from the internal combustion engine to the exhaust gas purification unit, and is capable of withstanding the environment and conditions of use as an exhaust gas purification device. It is not particularly limited. Specifically, the case may be composed of a tubular member (pipe) made of a metal material such as stainless steel, or may be formed by a method of stacking a plurality of press-molded members (so-called “Monaka method”). It may be formed or may be formed by casting.

The exhaust supply section includes first to third sections enumerated below. The first part is a member that defines a first space that is an annular flow path that surrounds a first straight line that includes the axis of the exhaust purification unit. The second part is a member that is connected to the upstream end of the first part and defines the second space, which is a flow path for supplying the exhaust gas to the first space. The third part is disposed between the upstream end of the case of the exhaust purification unit and the first part, closes the upstream end of the case, and supplies exhaust gas from the first space to the exhaust purification unit. It is a member that defines a third space, which is a flow path that flows through.

That is, in the exhaust supply section, the exhaust gas discharged from the internal combustion engine is guided to the first section through the second space defined by the second section, and flows through the annular flow path defined by the first section. and is led to the exhaust purification unit via the third space defined by the third part. The first space is not particularly limited as long as it is an annular flow path surrounding the first straight line. For example, it may be an annular flow path surrounding the first straight line only once, or may It may also be a spiral or helical channel that surrounds multiple times.

The downstream end of the first space may or may not communicate with the third space. In other words, the downstream end of the first portion may have an opening communicating between the first space and the third space, or may be closed. From the standpoint of making the exhaust evenly hit the front end surface of the exhaust purification unit, the downstream end of the first portion is typically closed.

Further, in the first device, a slit extending along the first space (which is an annular channel) and communicating between the first space and the third space is formed on the third part side of the first part. ing. More preferably, the slit is formed at a position on the third portion side of the first portion and on the first straight line side. The exhaust gas that has flowed into the first space as described above flows from the first space through the slit into the third space defined by the third portion. A specific configuration of the slit is not particularly limited as long as it extends along the first space, connects the first space and the third space, and is formed on the third portion side of the first portion.

However, it is preferable to determine the width and/or length of the slit so that the slit has an opening area that does not excessively increase the pressure loss of the exhaust gas passing through the slit. Further, the width of the slit may be constant over the entire length of the slit, may vary depending on the position in the longitudinal direction of the slit, or may vary along the longitudinal direction of the slit. good.

Further, from the viewpoint of uniforming the exhaust air hitting the front end surface of the exhaust purification unit, the slit typically has a point-symmetrical shape about the first straight line. Specifically, for example, when the exhaust purification unit has a cylindrical shape, the slit can have a circular shape arranged coaxially with the exhaust purification unit. Further, for example, when the exhaust gas purification unit has an elliptical cylindrical shape, the slit can have an elliptical shape arranged coaxially with the exhaust gas purification unit. Furthermore, for example, when the exhaust gas purification unit has a polygonal prismatic shape, the slit may have a polygonal shape arranged coaxially with the exhaust gas purification unit, or may be coaxial with the exhaust gas purification unit. It may have circular or elliptical shapes arranged in a shape.

In addition, in the first device, the first section is configured such that the cross-sectional area of the first space decreases from the upstream side to the downstream side. Here, the "cross-sectional area of the first space" literally means the area of the "cross-section of the first space", and as is well known to those skilled in the art, the "cross-section" is defined as "an object perpendicular to its extension direction. It is a cut along the plane of the eggplant" (see, for example, "Kojien 4th Edition" published by Iwanami Shoten Co., Ltd.). Therefore, the "cross section of the first space" is a cut of the first space cut along a plane including the first straight line, which is a straight line including the axis of the exhaust purification unit, and the "cross section of the first space" is It is the area of the "cut". In this way, the cross section of the first space becomes smaller as it progresses from the upstream side to the downstream side. The flow rate distribution of the exhaust gas flowing from the first space to the third space can be made more uniform.

In addition, in the above-mentioned conventional exhaust purification device (hereinafter sometimes referred to as "conventional device"), the flow of exhaust gas is made uniform by swirling the exhaust gas in the space on the upstream side of the exhaust gas purification unit. to make the contact of the exhaust gas with the front end surface of the exhaust purification unit uniform. However, in such a conventional device, as described above, when the rotational speed of the internal combustion engine is high (the flow velocity of the exhaust gas is high), the exhaust gas hits the front end surface of the exhaust purification unit unevenly. There is fear.

On the other hand, according to the first device having the configuration described above, compared to the conventional device, regardless of whether the rotation speed of the internal combustion engine is high or low (that is, regardless of whether the flow velocity of the exhaust gas discharged from the internal combustion engine is high or low), (1) The front end surface of the exhaust purification unit such as the exhaust purification catalyst and/or the filter can be more uniformly hit by the exhaust.

More preferably, the A/R ratio, which is the ratio of the cross-sectional area A of the first space to the distance R between the area center of gravity of the cross-section of the first space and the first straight line, decreases from upstream to downstream. The first part is constructed. In this case, the first part may be configured such that the A/R ratio decreases at a constant rate as it progresses from the upstream side to the downstream side (the rate of decrease in the A/R ratio is constant). Alternatively, the reduction rate of the A/R ratio does not necessarily have to be constant as long as it is possible to make the exhaust hitting the front end face of the exhaust purification unit more uniform. For example, the first part so that the ratio of the amount of decrease in the A/R ratio to the amount of increase in the angle of rotation from the upstream side to the downstream side around the first straight line that includes the axis of the exhaust gas purification unit is constant. may be configured. Alternatively, for example, even if the first section is configured such that the ratio of the A/R ratio at two locations facing each other across the first straight line (i.e., facing each other at a position shifted by 180°) is always constant. good.

The first device is an exhaust gas purification device including an exhaust gas purification unit, which is a columnar member for purifying exhaust gas emitted from an internal combustion engine, and a case, which is a cylindrical member that encloses the exhaust gas purification unit. Therefore, as long as it is downstream of the internal combustion engine in the flow path of the exhaust gas discharged from the internal combustion engine, it may be arranged at any position. For example, the first device may be arranged downstream and adjacent to the exhaust system of the internal combustion engine (e.g., exhaust manifold, etc.), or downstream of other devices (e.g., other exhaust purification devices, etc.). may be located adjacent to the

In addition, the exhaust gas supply unit does not necessarily have to be configured integrally with the exhaust purification unit. It may be configured as an adapter that connects an exhaust purification device, etc.) and the exhaust purification unit. Alternatively, the exhaust gas supply unit may be configured integrally with an exhaust flow path located upstream of the exhaust gas supply unit. Furthermore, at least a portion (e.g., side walls) of the third portion defining the third space of the exhaust gas supply portion may be configured by, for example, a portion (e.g., tapered portion) on the upstream side of the case of the exhaust purification portion. good. Specifically, for example, the first and second parts of the exhaust gas supply unit are integrally formed with the cylinder head provided in the internal combustion engine, and the third part of the exhaust gas supply unit is formed in the case of the exhaust purification unit as described above. It may be configured by an upstream portion. With such a configuration, for example, the first and second parts of the exhaust gas supply section having a complicated shape and the cylinder head of the internal combustion engine can be integrally and easily formed by casting.

One specific example of the first device will be described in more detail below with reference to the drawings. FIG. 1 is a schematic perspective view showing an example of the configuration of the first device. FIG. 2 illustrates a state in which the first device 101 cut by a plane including a first straight line L1, which is a straight line including the axis of the exhaust purification unit provided in the first device 101 illustrated in FIG. 1, is observed from the cut surface side. It is a schematic diagram. A first device 101 illustrated in FIGS. 1 and 2 is an exhaust gas purification device including an exhaust gas purification unit 10 and an exhaust gas supply unit 20 .

The exhaust purification unit 10 includes an exhaust purification unit 11 that is a columnar member for purifying exhaust emitted from an internal combustion engine (not shown) and a case 12 that is a cylindrical member that encloses the exhaust purification unit 11 . The exhaust purification unit 11 provided in the first device 101 has a cylindrical shape. In addition, in the first device 101, the exhaust purification unit 11 is held and fixed at a predetermined position inside the case 12 by the restoring force of the holding member 13 held between the exhaust purification unit 11 and the case 12 under pressure. It is

The exhaust gas supply unit 20 is connected to the upstream end of the case 12 of the exhaust gas purification unit 10 and defines a flow path for supplying the exhaust gas to the exhaust gas purification unit 11 . The exhaust supply section 20 comprises a first section 21, a second section 22 and a third section 23 listed below.

The first part 21 is a member that defines a first space that is an annular flow path that surrounds a first straight line L<b>1 that is a straight line that includes the axis of the exhaust purification unit 11 . The first space defined by the first part 21 of the first device 101 is an annular flow path that surrounds the first straight line L1 only once. The first part 21 that defines such a first space is configured by a tubular member that defines the first space, and has an annular outer shape corresponding to the shape of the first space, which is an annular flow path.

The second part 22 is a member that is connected to the upstream end of the first part 21 and defines a second space that is a flow path that supplies exhaust gas to the first space. At the upstream end of the second portion 22 of the first device 101, a flange 22f is formed to connect with an exhaust flow path (for example, an exhaust pipe of an internal combustion engine (not shown)) located further upstream. It is On the other hand, the downstream end of the second portion 22 is airtightly connected to the upstream end of the first portion 21 . Thereby, the second part 22 can supply the exhaust gas discharged from the internal combustion engine (not shown) to the first space via the second space.

The third part 23 is disposed between the upstream end of the case 12 of the exhaust gas purification unit 10 and the first part 21 to block the upstream end of the case 12 and to allow the exhaust gas purification unit to move from the first space to the exhaust gas purification unit. It is a member that defines a third space, which is a flow path for supplying exhaust gas to 11 . The third space defined by the third portion 23 provided in the first device 101 is a channel having a substantially truncated cone shape having a top surface on the side of the first portion 21 and a bottom surface on the side of the exhaust purification unit 11. . The third portion 23 that defines such a third space is configured by a plate-like member that defines the top surface of the third space on the side of the first portion 21 and the side surface of the third space, and has a substantially truncated cone shape. It has a substantially truncated conical outer shape corresponding to the shape of the third space, which is the flow path of the .

However, the third part 23 is arranged between the upstream end of the case 12 of the exhaust purification unit 10 and the first part 21 to block the upstream end of the case 12 and to close the first space. As long as it is possible to define the third space, which is a flow path for supplying the exhaust gas from the exhaust purification unit 11, the present invention is not limited to the above. Therefore, the shape of the third space is also not limited to the above as long as it is possible to supply the exhaust gas from the first space to the exhaust purification unit 11 .

Furthermore, at a position on the side of the third part 23 of the first part 21 provided in the first device 101 and on the side of the first straight line L1, there is a A slit 21s communicating with is formed. In the first device 101, the exhaust purification unit 11 has a cylindrical shape as described above, and the slit 21s has a circular shape centered on the first straight line L1. That is, the slit 21s has a circular shape arranged coaxially with the exhaust purification unit 11 .

In addition, the first portion 21 is configured such that the cross-sectional area of the first space decreases from the upstream side to the downstream side. In the first device 101, as the A/R ratio, which is the ratio of the cross-sectional area A of the first space to the distance R between the area center of gravity of the cross-section of the first space and the first straight line L1, proceeds from the upstream side to the downstream side, The first portion 21 is configured to be small.

As described above, the cross section of the first space becomes smaller as it progresses from the upstream side to the downstream side. The flow rate distribution of the exhaust gas flowing from the first space to the third space can be made more uniform. In addition, according to such a configuration, when the rotational speed of the internal combustion engine is high (the flow velocity of the exhaust gas is high) as occurs in the conventional exhaust gas purification device described above, the exhaust hits the front end surface of the exhaust purification unit. can reduce the problem of non-uniformity.

<effect>
As described above, according to the first device, the exhaust purification catalyst and the / Or, it is possible to more evenly hit the front end face of the exhaust purification unit such as a filter.

<<Second embodiment>>
Hereinafter, an exhaust purification device (hereinafter sometimes referred to as "second device") according to a second embodiment of the present invention will be described with reference to the drawings.

As described above, in the first device, the slit extending along the first space (which is an annular channel) and communicating between the first space and the third space is provided on the third part side of the first part. , and the first portion is configured such that the cross-sectional area of the first space decreases from the upstream side to the downstream side. Therefore, according to the first device, compared to the conventional device, regardless of whether the rotation speed of the internal combustion engine is high or low (that is, regardless of the flow velocity of the exhaust gas discharged from the internal combustion engine), the exhaust purification catalyst and/or filter It is possible to make the contact of the exhaust gas with the front end face of the exhaust purification unit such as the above more uniform.

However, the exhaust gas supplied to the front end surface of the exhaust purification unit flows from the first space to the third space via the slit. Therefore, at least part of the exhaust gas supplied to the front end face of the exhaust purification unit tends to flow intensively into the region having an annular shape corresponding to the shape of the slit. In addition, for example, due to the action of the Coanda effect by the side wall defining the third space and/or the centrifugal force accompanying the swirling of the exhaust gas flowing from the first space, which is an annular flow path, into the third space, the front end surface of the exhaust purification unit At least a portion of the exhaust supplied to the air tends to flow downstream along the sidewalls that define the third space. Furthermore, these tendencies tend to become stronger as the rotational speed of the internal combustion engine increases (that is, as the flow velocity of the exhaust gas discharged from the internal combustion engine increases).

Therefore, from the viewpoint of making the exhaust air hit the front end face of the exhaust purification unit evenly, means for changing the flow direction and/or the flow velocity distribution of the exhaust gas in the third space is further provided. It is preferable to positively uniformize the impact of the exhaust gas on the front end surface of the .

<composition>
Therefore, the second device is the above-described first device, and further includes wind direction adjusting means, which is a member and/or mechanism configured to change the flow direction and/or flow velocity distribution of the exhaust gas in the third space. , is an exhaust purification device.

The configuration of the wind direction adjusting means is not particularly limited as long as it is possible to change the flow direction and/or the flow velocity distribution of the exhaust gas in the third space to make the exhaust gas hit the front end face of the exhaust purification unit more uniform. A specific configuration of the airflow direction adjusting means will be described in detail below while exemplifying some modifications.

<Modification 2-1>
As described above, at least part of the exhaust gas supplied to the front end surface of the exhaust purification unit flows intensively into the region having an annular shape corresponding to the shape of the slit, or flows into the side wall defining the third space. tend to flow downstream along the As a result, the amount of exhaust gas supplied to the central region of the front end face of the exhaust gas purification unit is relatively small, and there is a risk that the exhaust gas will hit the front end face of the exhaust gas purification unit unevenly. As a result, for example, as described above, it may become difficult to uniformly raise the temperature of the exhaust purification catalyst, or local clogging of the filter may occur.

Therefore, in the second device according to the modified example 2-1, the third part further includes an opening formed to open in a region on the first straight line side of the slit in the third space. In other words, the opening provided in the third part opens into the third space in the area inside the annular slit. In addition, the exhaust gas supply unit further includes a fourth part that is a member that defines a fourth space that is an exhaust flow path that communicates the second space and the third space via the opening. That is, the wind direction adjusting means provided in the second device according to Modification 2-1 separates the second space and the third space through an opening that opens in the area on the first straight line side of the slit in the third space. It includes a fourth portion that is a member that defines a fourth space that is a communicating exhaust flow path.

FIG. 3 is a schematic perspective view showing an example of the configuration of a second device according to modification 2-1. FIG. 4 is a schematic perspective view of the second device according to Modification 2-1 illustrated in FIG. 3 when observed from an angle different from that in FIG. FIG. 5 shows the second device cut by a plane including the first straight line, which is a straight line including the axis of the exhaust purification unit provided in the second device according to Modification 2-1 illustrated in FIG. 3, observed from the cut surface side. It is a schematic diagram which illustrates a state.

A second device 102a according to Modified Example 2-1 illustrated in FIGS. The exhaust gas supply unit 20 further includes a fourth part 24 which is a member that defines a fourth space that is an exhaust flow path that communicates the second space and the third space via the opening 23a. It has the same configuration as the first device 101 illustrated in FIGS. 1 and 2 except for points.

In the second device 102a, part of the exhaust gas that has flowed into the second space is led to the third space through the slits 21s through the first space defined by the first part 21, and the remaining exhaust gas is directed to the fourth space. Through the fourth space defined by the portion 24, the light is led from the opening 23a to the third space. Therefore, the amount of exhaust gas supplied to the central region of the front end surface of the exhaust gas purification unit 11 increases compared to the case where the opening 23a and the fourth portion 24 are not provided. The exhaust hits the surface more evenly. As a result, for example, as described above, problems such as difficulty in uniformly increasing the temperature of the exhaust purification catalyst and local clogging of the filter can be reduced.

The opening 23a may be, for example, a simple hole that opens into the third space as illustrated in FIG. , a nozzle projecting from the periphery of the opening 23a toward the front end face of the exhaust purification unit 11 may be provided. Further, in the latter case, even if the nozzle is of a so-called "convergent type" in which the cross section becomes smaller as it approaches the front end surface of the exhaust purification unit 11, the cross section becomes larger as it approaches the front end surface of the exhaust purification unit 11. It may be a so-called "divergent type" or a straight tube type (straight type) having a constant cross section. Further, the nozzle may be composed of a combination of two or more sections selected from the group consisting of a convergent section, a divergent section and a straight tube section.

The size and shape of the opening 23a and the shape (e.g., cross-sectional area, length, etc.) of the nozzle (in the case where the opening 23a is provided with a nozzle) are determined, for example, by the assumed rotational speed of the internal combustion engine (exhaust flow rate). etc., can be determined as appropriate.

Preferably, the fourth section further includes a flow rate adjustment mechanism configured to increase or decrease the flow rate of exhaust gas flowing into the fourth space. The configuration of the flow rate adjusting mechanism is not particularly limited as long as it is possible to increase or decrease the flow rate of the exhaust gas flowing through the fourth space. For example, the flow rate adjustment mechanism may be a valve (for example, an on-off valve, a flow rate control valve, etc.) interposed in the fourth space, or a three-way valve provided at a location where the fourth space branches from the second space. It may be a valve.

According to the flow rate adjustment mechanism as described above, the flow rate of the exhaust gas guided from the slits 21s to the third space via the first space defined by the first part 21 and the fourth space defined by the fourth part 24 It is possible to adjust the ratio with the flow rate of the exhaust gas that is led from the opening 23a to the third space via the space. Therefore, for example, depending on the rotational speed of the internal combustion engine (that is, the flow speed of the exhaust gas discharged from the internal combustion engine), the flow rate adjustment mechanism is controlled to control the flow rate of the exhaust gas guided from the slit 21s to the third space. and the flow rate of the exhaust gas led from the opening 23a to the third space can be adjusted. As a result, compared with the case where such a flow rate adjusting mechanism is not provided, it is possible to more evenly hit the front end surface of the exhaust purification unit 11 with the exhaust gas.

More preferably, the flow rate adjusting mechanism adjusts the ratio of the flow rate of the exhaust gas led to the third space from the opening 23a to the flow rate of the exhaust gas led to the third space from the slit 21s in the range of 100:0 to 0:100. It is configured so that it can be changed continuously or stepwise within. According to such a configuration, for example, when it is possible to uniform the exhaust air hitting the front end surface of the exhaust gas purification unit 11 only by the exhaust gas guided to the third space from the slit 21s, the fourth space can be used. The amount of exhaust gas supplied to the central region of the front end face of the exhaust gas purification unit 11 is relatively small and the amount of exhaust gas supplied to the central region of the front end face of the exhaust gas purification unit 11 is relatively small only by the exhaust gas that is guided to the third space through the slits 21s. When the exhaust air hits the front end face of the purification unit 11 unevenly, the flow rate of the exhaust gas flowing into the fourth space can be increased to make the exhaust air hit the front end face of the exhaust gas purification unit 11 uniform. . In addition, when it is necessary to quickly reach the activation temperature of the exhaust purification catalyst, such as when the internal combustion engine is cold-started, the flow rate of the exhaust gas flowing into the fourth space is increased, and the center of the exhaust purification catalyst is increased. The temperature of the region can be raised rapidly.

<Modification 2-2>
As described above, in the first device, the slit extending along the first space (which is an annular channel) and communicating between the first space and the third space is provided on the third part side of the first part. is formed in More preferably, the slit is formed at a position on the third portion side of the first portion and on the first straight line side.

Therefore, as illustrated in FIGS. 6A and 6B, the flow vector of at least part of the exhaust gas flowing from the first space to the third space via the slit 21s is the first space from the slit 21s. It contains a component pointing to the straight line L1 (see the arrow drawn by the thick solid line). The exhaust gas thus flowing from the slit 21s toward the first straight line L1 eventually collides with each other in the vicinity of the first straight line L1, and is then guided to the front end face of the exhaust purification unit 11. As shown in FIG.

However, from the viewpoint of efficiently guiding the exhaust gas to the front end face of the exhaust purification unit, the direction of the flow of the exhaust gas flowing from the first space to the third space through the slits 21s should be parallel to the first straight line L1 and It is preferable to approach the direction toward the front end face of the exhaust purification unit 11 .

Therefore, the second device according to Modified Example 2-2 is a second device including the second device according to Modified Example 2-1 described above, in which the first straight line The third part further includes an inner wind direction adjusting member that is a cylindrical member protruding toward the exhaust gas purification unit in the side region. In other words, the inner wind direction adjusting member provided in the third section is a cylindrical member that protrudes toward the front end surface of the exhaust purification unit 11 in a region inside the annular slit of the inner wall surface that defines the third space. be. That is, the wind direction adjusting means provided in the second device according to Modification 2-2 is a tubular member protruding toward the exhaust gas purification unit in a region on the first straight line side of the slit in the inner wall surface of the third portion. It includes an inner wind direction adjusting member which is a member.

The configuration of the inner wind direction adjusting member is not particularly limited as long as it is a cylindrical member protruding toward the exhaust purification unit in a region on the first straight line side of the slit in the inner wall surface of the third portion. The inner wind direction adjusting member may be of a convergent type, a divergent type, or a straight tube type. Furthermore, the inner wind direction adjusting member may be configured by a combination of two or more portions selected from the group consisting of a convergent portion, a divergent portion and a straight pipe portion.

FIG. 7 is a schematic diagram illustrating a state in which the second device cut by a plane including the first straight line, which is a straight line including the axis of the exhaust purification unit provided in the second device according to modification 2-2, is observed from the cut surface side. It is a diagram. A second device 102b according to Modified Example 2-2 illustrated in FIG. 7 protrudes toward the exhaust purification unit 11 in a region closer to the first straight line L1 than the slit 21s in the inner wall surface of the third portion 23. It has the same configuration as the first device 101 illustrated in FIG. 2 except that the third section 23 further includes an inner wind direction adjusting member 23di that is a cylindrical member.

More specifically, in a second device 102b according to Modified Example 2-2 illustrated in FIG. Prepare. On the other hand, a second device 102b according to Modification 2-2 illustrated in FIG. The third portion 23 further includes an inner wind direction adjusting member 23di formed of a tubular member in which the inclination angle of the side wall approaches the angle parallel to the first straight line L1 as it approaches the front end surface. In other words, the convergent type inner wind direction adjusting member 23di provided in the second device 102b illustrated in FIG. It is a curve whose inclination angle with respect to the first straight line L1 decreases as it increases.

In the second device 102b configured as described above, of the exhaust that flows from the first space to the third space through the slit 21s, the exhaust that travels toward the first straight line L1 contacts the inner wind direction adjusting member 23di. , is deflected towards the front end face of the exhaust purification unit 11 (see the arrow drawn by the thick solid line). As a result, according to the second device 102b, the direction of the flow of the exhaust gas flowing from the first space to the third space through the slit 21s is parallel to the first straight line L1 and toward the front end surface of the exhaust purification unit 11. By aligning the direction, the exhaust gas can be efficiently guided to the front end surface of the exhaust purification unit 11. - 特許庁

<Modification 2-3>
By the way, the tip of the above-described inner wind direction adjusting member 23di on the front end surface side of the exhaust purification unit 11 may be closed. In other words, the inner wind direction adjusting member 23di is formed of a bottomed cylindrical member that protrudes toward the exhaust purification unit 11 in a region closer to the first straight line L1 than the slit 21s in the inner wall surface of the third portion 23. It may be constituted by the side surface of the protrusion.

Therefore, the second device according to Modified Example 2-3 is the second device according to Modified Example 2-2 described above, in which exhaust purification is performed in a region on the first straight line side of the slit on the inner wall surface of the third portion. In the exhaust purification device, the third part further includes a projection projecting toward the unit side, and the inner airflow direction adjusting member is configured by the side surface of the projection. That is, the wind direction adjusting means provided in the second device according to the modification 2-3 is adjusted by the side surface of the projection projecting toward the exhaust gas purification unit in the area on the first straight line side from the slit of the inner wall surface of the third part. Including a configured inner wind directing member.

FIG. 8 is a schematic diagram illustrating a state in which the second device cut by a plane including the first straight line, which is a straight line including the axis of the exhaust purification unit provided in the second device according to modification 2-3, is observed from the cut surface side. It is a diagram. The second device 102c according to the modified example 2-3 illustrated in (a) of FIG. It has the same configuration as the second device 102b according to Modification 2-2 illustrated in FIG.

In the second device 102c according to Modified Example 2-3 having the configuration described above, as in the above-described second device 102b, out of the exhaust gas flowing from the first space to the third space through the slit 21s, Exhaust air directed toward one straight line L1 contacts the inner wind direction adjusting member 23di, which is the side surface of the projection 23p, and is deflected toward the front end surface of the exhaust purification unit 11. As shown in FIG. As a result, even with the second device 102c, the direction of the flow of the exhaust gas flowing from the first space to the third space through the slit 21s is parallel to the first straight line L1 and directed toward the front end surface of the exhaust purification unit 11. , the exhaust gas can be efficiently guided to the front end surface of the exhaust purification unit 11 .

In addition, in the second device according to the modified example 2-3 having the configuration as described above, as in the second device according to the modified example 2-1 described above, the slit of the third space is located on the first straight line side. The third part further includes an opening formed to open to the region, and is a member that defines a fourth space that is an exhaust flow path that communicates the second space and the third space via the opening. A fourth part may also be provided. FIG. 8B shows the second device cut by a plane including the first straight line, which is a straight line including the axis of the exhaust purification unit provided in the second device according to Modification 2-3 having such a configuration. It is a schematic diagram which illustrates the state observed from the surface side.

In the second device 102c according to the modified example 2-3 illustrated in FIG. 8B, a projection protruding toward the exhaust purification unit 11 side in the region on the first straight line L1 side of the slit 21s of the third space An opening 23a opens on the top surface of the protrusion 23p. is defined by In the second device 102c according to Modified Example 2-3 having such a configuration, the fourth portion 24 and the inner airflow direction adjusting member 23di formed by the side surface of the projection 23p are used together to allow the first airflow to pass through the slit 21s. The direction of the flow of exhaust gas flowing from the space into the third space is parallel to the first straight line L1 and is effectively brought closer to the front end face of the exhaust gas purification unit 11, so that the exhaust gas is discharged to the front end face of the exhaust gas purification unit 11. can be derived more efficiently (see arrows drawn by thick solid lines).

<Modification 2-4>
By the way, as described above, at least part of the exhaust gas supplied to the front end surface of the exhaust purification unit is caused by the action of the centrifugal force caused by the swirl of the exhaust gas flowing from the first space, which is an annular flow path, into the third space. tend to flow downstream along the sidewalls that define the third space. Furthermore, these tendencies tend to become stronger as the rotational speed of the internal combustion engine increases (that is, as the flow velocity of the exhaust gas discharged from the internal combustion engine increases).

Therefore, from the viewpoint of uniforming the contact of the exhaust gas with the front end surface of the exhaust purification unit, it is necessary to suppress the swirl of the exhaust gas flowing from the first space to the third space, and direct the direction of the flow of the exhaust gas to the first straight line L1. is parallel to and approaches the front end surface of the exhaust purification unit 11 .

Therefore, the second device according to Modification 2-4 is a second device including the second devices according to Modifications 2-1 to 2-3 described above, and is provided at least downstream of the slit. The exhaust purification device further includes a plurality of fins provided in adjacent regions. Further, the fins are configured to come into contact with the exhaust gas flowing into the third space from the slits so that the direction of the exhaust gas approaches the direction parallel to the first straight line and toward the exhaust purification unit. That is, the wind direction adjusting means provided in the second device according to the modified example 2-4 is provided at least in a region adjacent to the downstream side of the slit and is in contact with the exhaust flowing into the third space from the slit to adjust the direction of the exhaust. parallel to the first straight line and oriented toward the exhaust purification unit.

The configuration of the fins is not particularly limited as long as it is possible to contact the exhaust gas flowing into the third space from the slits and make the direction of the exhaust gas parallel to the first straight line and closer to the direction toward the exhaust purification unit. The specific configuration of the fins (for example, the number, the size of each fin, the area where the fins are arranged, etc.) is, for example, the assumed rotation speed of the internal combustion engine (exhaust flow rate), the first space can be determined as appropriate according to the radius of the annular shape of , the width of the slit, and the like.

For example, the surface of the fin that contacts the exhaust gas flowing into the third space from the slit may be a plane parallel to the first straight line. In other words, the fins may be configured by flat plate-like members parallel to the first straight line. Alternatively, the surface of the fin that contacts the exhaust gas flowing into the third space from the slit may be a flat surface that is inclined with respect to the first straight line. In other words, the fins may be composed of flat plate-shaped members forming a predetermined angle with respect to the first straight line. In this case, the surface of the fin that comes into contact with the exhaust gas flowing into the third space from the slit is the surface facing the front end surface of the exhaust purification unit, out of the two main surfaces of the flat plate member that constitutes the fin. .

Alternatively, the surfaces of the fins that come into contact with the exhaust flowing into the third space from the slits may be curved surfaces configured so that the angle of inclination with respect to the first straight line decreases as the fins progress from the upstream side to the downstream side. In this case, the surface of the fin that comes into contact with the exhaust gas flowing into the third space from the slit is the concave surface on the side facing the front end surface of the exhaust purification unit, of the two main surfaces of the flat plate member that constitutes the fin. .

FIG. 9 is a schematic diagram illustrating a state in which the second device cut by a plane including the first straight line, which is a straight line including the axis of the exhaust purification unit provided in the second device according to modification 2-4, is observed from the cut surface side. It is a diagram. FIG. 10 is a schematic diagram illustrating a state in which the cross-section of the second device according to modification 2-4 illustrated in FIG. 9 is observed from the side of the exhaust purification unit at a predetermined elevation angle. FIG. 11 is a schematic diagram illustrating a state of the second device according to the modified example 2-4 illustrated in FIGS. 9 and 10 viewed from the first section side in a direction parallel to the first straight line. In FIG. 11, for the purpose of facilitating the understanding of the configuration of the second device according to Modification 2-4, slits that are normally invisible from the outside are indicated by thick solid lines.

Except that the second device 102d according to the modified example 2-4 illustrated in FIGS. It has the same configuration as the second device 102c according to Modification 2-3 illustrated in FIG. 8(a). The fins 23f are configured to make contact with the exhaust gas flowing into the third space from the slits 21s so that the direction of the exhaust gas is parallel to the first straight line L1 and closer to the direction toward the exhaust purification unit 11 .

More specifically, the fins 23f included in the second device 102d illustrated in FIGS. 9 to 11 are parallel to the first straight line L1 and arranged axially symmetrically with respect to the first straight line L1 at intervals of 30°. It is composed of 12 flat plate-shaped members. That is, in the second device 102d, the surface of the fin 23f that contacts the exhaust gas flowing into the third space from the slit 21s is a plane parallel to the first straight line L1.

In the second device 102d configured as described above, the swirl of exhaust gas flowing from the first space, which is an annular flow path, into the third space is suppressed by contact with the fins 23f, and the centrifugal force accompanying the swirl is applied. can reduce the tendency of the exhaust to flow downstream along the sidewalls that define the third space. As a result, the direction of the flow of the exhaust gas flowing from the first space to the third space through the slit 21s is effectively brought closer to the direction parallel to the first straight line L1 and toward the front end surface of the exhaust purification unit 11, Exhaust gas can be guided more efficiently to the front end surface of the exhaust purification unit 11 (see the arrow drawn by the thick solid line).

<Modification 2-5>
By the way, as described above, the exhaust gas supplied to the front end surface of the exhaust purification unit flows from the first space, which is an annular flow path, into the third space via the slit. Therefore, at least part of the exhaust gas supplied to the front end face of the exhaust purification unit flows into the third space from the first space, which is, for example, the Coanda effect due to the side wall defining the third space and/or the annular flow path. At least part of the exhaust gas supplied to the front end surface of the exhaust purification unit tends to flow downstream along the side wall that defines the third space due to the action of centrifugal force or the like that accompanies swirling of the exhaust gas. Furthermore, these tendencies tend to become stronger as the rotational speed of the internal combustion engine increases (that is, as the flow velocity of the exhaust gas discharged from the internal combustion engine increases).

Therefore, from the viewpoint of making the exhaust air hit the front end face of the exhaust purification unit evenly, means for changing the flow direction and/or the flow velocity distribution of the exhaust gas in the third space is further provided. It is preferable to positively uniformize the impact of the exhaust gas on the front end surface of the .

Therefore, the second device according to Modification 2-5 is a second device including the second devices according to Modifications 2-1 to 2-4 described above, and the inner wall surface of the third part In the exhaust purification device, the third section further includes an outer wind direction adjusting member, which is a cylindrical member projecting toward the exhaust purification unit in a region on the opposite side of the first straight line from the slit. In other words, the outer wind direction adjusting member included in the third section is a cylindrical member that protrudes toward the front end surface of the exhaust purification unit 11 in a region outside the annular slit of the inner wall surface that defines the third space. be. That is, the airflow direction adjusting means provided in the second device according to the modification 2-5 protrudes toward the exhaust gas purification unit in a region on the opposite side of the first straight line from the slit of the inner wall surface of the third portion. It includes an outer wind direction adjusting member, which is a tubular member.

The configuration of the outer wind direction adjusting member is not particularly limited as long as it is a cylindrical member protruding toward the exhaust purification unit in a region on the opposite side of the first straight line from the slit in the inner wall surface of the third portion. The outer wind direction adjusting member may be of a convergent type, a divergent type, or a straight tube type. Furthermore, the outer wind direction adjusting member may be configured by a combination of two or more portions selected from the group consisting of a convergent type portion, a divergent type portion and a straight tube type portion.

However, from the viewpoint of making the exhaust air hit the front end surface of the exhaust gas purification unit evenly, the exhaust gas that has flowed from the first space, which is an annular flow path, into the third space via the slit is Instead of concentrating on a specific region (for example, the central region) on the front end face of the exhaust gas purification unit or concentrating on a region having an annular shape corresponding to the shape of the slit, the entire front end face of the exhaust gas purification unit A uniform supply is preferred.

Therefore, preferably, at least a portion of the outer wind direction adjusting member near the end on the side of the exhaust gas purification unit is formed of a divergent type member whose cross section increases as it approaches the front end surface of the exhaust gas cleaning unit. More preferably, the outer wind direction adjusting member has a divergent type member in the vicinity of the end on the side of the exhaust gas purification unit, and the other portion is formed by a straight tube type member, which is so-called "broadening at the bottom". It is made up of “mold” members.

FIG. 12 is a schematic diagram illustrating a state in which the second device cut by a plane including the first straight line, which is a straight line including the axis of the exhaust purification unit provided in the second device according to modification 2-5, is observed from the cut surface side. It is a diagram. A second device 102e according to Modified Example 2-5 illustrated in FIG. 12 protrudes toward the exhaust purification unit 11 in a region on the opposite side of the first straight line L1 from the slit 21s in the inner wall surface of the third portion 23. It has the same configuration as the second device 102c illustrated in FIG. 8(a), except that the third section 23 further includes an outer wind direction adjusting member 23do, which is a tubular member that is closed.

More specifically, the outer wind direction adjusting member 23do provided in the second device 102e according to the modified example 2-5 illustrated in FIG. The cage and other parts are constructed by a flared-bottom type member constructed by a straight pipe type member.

In the second device 102e configured as described above, the exhaust gas flowing from the first space to the third space through the slit 21s flows downstream along the side wall of the third portion 23 that defines the third space. The exhaust gas that is about to flow first contacts the straight pipe portion on the base end side (upper side in the drawing) of the outer airflow direction adjusting member 23do, and moves toward the front end surface of the exhaust purification unit 11 (in the first straight line L1 parallel orientation). The exhaust then contacts the divergent-type portion on the tip side (lower side in the drawing) of the outer wind direction adjusting member 23do, and is deflected (thick (see arrows drawn by solid lines). As a result, according to the second device 102e, the flow direction of the exhaust gas flowing from the first space to the third space through the slit 21s is parallel to the first straight line L1 and directed to the front end surface of the exhaust purification unit 11. By effectively approximating the direction, the exhaust gas can be guided to the front end surface of the exhaust purification unit 11 more efficiently.

<effect>
The exhaust purification device (second device) according to the second embodiment of the present invention has been described in detail above while showing various modifications. As is clear from the above description, according to the second device, by changing the flow direction and/or the flow velocity distribution of the exhaust gas in the third space by the wind direction adjusting means, it is possible to prevent the exhaust gas from hitting the front end surface of the exhaust purification unit. can be more aggressively homogenized.

<<Third Embodiment>>
Hereinafter, an exhaust purification device (hereinafter sometimes referred to as "third device") according to a third embodiment of the present invention will be described.

As described at the beginning of this specification, from the viewpoint of environmental protection, it is preferable to quickly bring the temperature of the exhaust gas purification catalyst to the activation temperature so that the desired exhaust gas purification function can be rapidly exhibited. . On the other hand, in a high load state such as a full load state (WOT), an exhaust purification unit such as an exhaust purification catalyst and/or a filter is excessively heated by high-temperature exhaust, for example, the deterioration of the exhaust purification unit is accelerated. It is likely to lead to problems. From the viewpoint of energy saving, it is possible to recover exhaust heat energy from the internal combustion engine, for example, to shorten the warm-up time of the internal combustion engine in cold weather, and to improve the heating efficiency of the cabin space and the like. preferable.

<composition>
Therefore, the third device is a device of the present invention including the above-described first device and the second device including various modifications, and is a member that defines the fifth space that is the flow path of the coolant of the internal combustion engine. An exhaust purification device, wherein the exhaust supply further comprises a fifth part. The fifth part is configured to allow heat exchange between at least the exhaust gas flowing in the first space and the refrigerant flowing in the fifth space.

The coolant is typically so-called "cooling water", but is not particularly limited as long as it is a coolant for cooling the internal combustion engine. For example, when the internal combustion engine has an oil-cooled cooling mechanism, the coolant is oil. Also, the configuration of the fifth section is not particularly limited as long as heat exchange is possible between at least the exhaust gas flowing in the first space and the refrigerant flowing in the fifth space. Typically, the fifth part is a member that defines a flow path for the coolant so that the coolant contacts at least the partition wall of the first part that defines the first space. In this case, heat exchange is performed between the exhaust gas flowing into the first space through the partition wall of the first part and the refrigerant flowing into the fifth space.

The heat exchange between the exhaust gas and the refrigerant is not necessarily limited to the heat exchange between the exhaust gas flowing in the first space and the refrigerant. The fifth part may be configured so that heat exchange with is also possible.

<effect>
As described above, the third device includes the fifth section configured to allow heat exchange between the refrigerant flowing in the fifth space defined by the fifth section and the exhaust gas flowing in at least the first space. Prepare. Therefore, even if the exhaust purification unit is likely to be excessively heated by extremely high-temperature exhaust gas under a high load condition, the heat exchange reduces the temperature of the exhaust gas, thereby preventing problems such as accelerated deterioration of the exhaust purification unit. can be reduced. In addition, by using the fifth part as a so-called "heat collector", exhaust heat energy from the internal combustion engine is recovered, for example, shortening the warm-up time of the internal combustion engine in cold weather, heating the cabin space, etc. You can improve efficiency.

Although several embodiments and variations having specific configurations have been described above for the purpose of illustrating the present invention, sometimes with reference to the accompanying drawings, the scope of the present invention is not limited to these exemplary embodiments. It should not be construed as being limited to the embodiments and modifications, and it goes without saying that modifications can be made as appropriate within the scope of the claims and the matters described in the specification.

DESCRIPTION OF SYMBOLS 10... Exhaust gas purification part 11... Exhaust gas purification unit 12... Case 13... Holding member 20... Exhaust gas supply part 21... First part 21s... Slit 22... Second part 22f... Flange 23... Second Part 3, 23a... opening, 23di... inner airflow direction adjusting member, 23do... outer airflow direction adjusting member, 23f... fin, 23p... projection, 24... fourth part, 101, 102a, 102b, 102c, 102d, 102e... exhaust purification Device.

Claims (12)

an exhaust purification unit comprising a columnar member for purifying exhaust gas emitted from an internal combustion engine, and a case that is a cylindrical member that encloses the exhaust purification unit;
an exhaust gas supply unit connected to an upstream end of the case and defining a flow path for supplying the exhaust gas to the exhaust purification unit;
An exhaust purification device comprising
The exhaust gas supply unit
a first part that is a member that defines a first space that is an annular flow path that surrounds a first straight line that is a straight line that includes the axis of the exhaust gas purification unit;
a second part that is a member that is connected to an upstream end of the first part and defines a second space that is a single flow path that supplies the exhaust gas to the first space;
A flow disposed between the upstream end of the case and the first portion to block the upstream end of the case and supply the exhaust gas from the first space to the exhaust purification unit. a third part that is a member that defines a third space that is a passage;
with
A slit extending along the first space and communicating the first space and the third space is formed on the third portion side of the first portion,
The slit has a circular shape centered on the first straight line,
The first part is configured such that the cross-sectional area of the first space decreases as it progresses from the upstream side to the downstream side.
Exhaust purification device. The exhaust purification device according to claim 1,
The slit is formed at a position on the third part side of the first part and on the first straight line side,
Exhaust purification device. The exhaust purification device according to claim 1 or claim 2,
In the first part, the A/R ratio, which is the ratio of the cross-sectional area A of the first space to the distance R between the area center of gravity of the cross-section of the first space and the first straight line, progresses from the upstream side to the downstream side. configured to decrease as
Exhaust purification device. An exhaust purification device according to any one of claims 1 to 3,
Further comprising wind direction adjusting means, which is a member and/or mechanism configured to change the flow direction and/or flow velocity distribution of the exhaust gas in the third space,
Exhaust purification device. An exhaust purification device according to claim 4,
The third part further comprises an opening formed to open in a region on the first straight line side of the slit in the third space,
The exhaust gas supply unit further includes a fourth part that is a member that defines a fourth space that is a channel of the exhaust gas that communicates the second space and the third space through the opening,
Exhaust purification device. An exhaust purification device according to claim 5,
The fourth part further comprises a flow rate adjustment mechanism configured to increase or decrease the flow rate of the exhaust gas flowing into the fourth space,
Exhaust purification device. The exhaust purification device according to any one of claims 4 to 6,
The third part further includes an inner wind direction adjusting member, which is a cylindrical member projecting toward the exhaust purification unit in a region on the first straight line side of the slit in the inner wall surface of the third part. prepare
Exhaust purification device. An exhaust purification device according to claim 7,
The third part further includes a projection projecting toward the exhaust purification unit in a region on the first straight line side of the slit in the inner wall surface of the third part,
The inner wind direction adjusting member is configured by a side surface of the protrusion,
Exhaust purification device. The exhaust purification device according to any one of claims 4 to 8,
The third part further comprises a plurality of fins provided at least in a region adjacent to the downstream side of the slit,
The fins are configured to come into contact with the exhaust gas flowing into the third space from the slits so that the direction of the exhaust gas approaches the direction parallel to the first straight line and toward the exhaust purification unit.
Exhaust purification device. An exhaust purification device according to claim 9,
The surface of the fin that contacts the exhaust gas flowing into the third space from the slit is a plane parallel to the first straight line, a plane inclined with respect to the first straight line, or progresses from the upstream side to the downstream side. Any curved surface configured so that the inclination angle with respect to the first straight line decreases as the
Exhaust purification device. An exhaust purification device according to any one of claims 4 to 10,
The third part is an outer wind direction adjusting member that is a cylindrical member protruding toward the exhaust purification unit in a region on the inner wall surface of the third part opposite to the first straight line from the slit. further comprising
Exhaust purification device. An exhaust purification device according to any one of claims 1 to 11,
The exhaust gas supply unit further includes a fifth part that is a member that defines a fifth space that is a coolant flow path of the internal combustion engine,
The fifth part is configured to allow heat exchange between at least the exhaust gas flowing in the first space and the refrigerant flowing in the fifth space.
Exhaust purification device.

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