JP2021050686A - Exhaust structure - Google Patents

Abstract

To provide an exhaust structure capable of further improving exhaust gas cooling performance.SOLUTION: An exhaust structure 1, which includes an exhaust pipe 2 through which exhaust gas flows, and an exhaust diffuser 3 provided at the downstream side end of the exhaust pipe 2, mixes exhaust gas with outside air in the exhaust diffuser 3 and exhausts it to the atmosphere. The exhaust structure 1 further includes a solid object 5 arranged in the exhaust pipe 2 for reducing the area of an opening portion at the downstream side end of the exhaust pipe 2. The solid object 5 is arranged so that a flow path 6 is provided between the outer peripheral face of the solid object 5 and the inner peripheral face of the exhaust pipe 2 for the exhaust gas to flow therethrough.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to an exhaust structure that discharges exhaust gas into the atmosphere.

Conventionally, an exhaust structure including an exhaust pipe through which exhaust gas discharged from an internal combustion engine flows and an exhaust diffuser (also referred to as an exhaust cooler) provided on the downstream side of the exhaust pipe is known (for example, Patent Documents). 1).

In this exhaust structure, for example, the outside air is taken in from the opening between the exhaust pipe and the exhaust diffuser, and the outside air and the exhaust gas are mixed in the exhaust diffuser. As a result, the temperature of the exhaust gas discharged into the atmosphere can be lowered.

JP-A-2009-91910

The exhaust structure of Patent Document 1 has room for improvement in terms of exhaust gas cooling performance.

An object of the present disclosure is to provide an exhaust structure capable of further improving the cooling performance of exhaust gas.

The exhaust structure according to one aspect of the present disclosure includes an exhaust pipe through which exhaust gas flows and an exhaust diffuser provided on the downstream side of the exhaust pipe, and the exhaust gas is mixed with outside air in the exhaust diffuser and is in the atmosphere. It is an exhaust structure that exhausts air to the exhaust pipe, and has a three-dimensional object arranged in the exhaust pipe so as to reduce the area of the opening portion of the downstream end portion of the exhaust pipe, and the three-dimensional object is the outer periphery of the three-dimensional object. It is arranged so that a flow path through which the exhaust gas flows is provided between the surface and the inner peripheral surface of the exhaust pipe.

According to the present disclosure, the cooling performance of the exhaust gas can be further improved.

Schematic cross-sectional view showing a configuration example of an exhaust structure according to an embodiment of the present disclosure. Schematic diagram of the exhaust structure shown in FIG. 1 as viewed from the direction of arrow A in FIG. Schematic cross-sectional view showing a configuration example of the exhaust structure according to the modified example 1 of the present disclosure.

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. The components common to each figure are designated by the same reference numerals, and their description will be omitted as appropriate.

The configuration of the exhaust structure 1 according to the present embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is a schematic cross-sectional view showing a configuration example of the exhaust structure 1 of the present embodiment. FIG. 2 is a schematic view of the exhaust structure 1 shown in FIG. 1 as viewed from the direction of arrow A in FIG.

In the following description, the left-right direction (horizontal direction) in FIG. 1 is referred to as "axial direction", and the vertical direction (vertical direction) in FIG. 1 is referred to as "radial direction". Further, in the following description, the left side in FIG. 1 is referred to as "upstream side", and the right side in FIG. 1 is referred to as "downstream side".

The exhaust structure 1 shown in FIGS. 1 and 2 is mounted on, for example, a vehicle equipped with an internal combustion engine. The internal combustion engine may be a diesel engine or a gasoline engine.

The exhaust structure 1 has an exhaust pipe 2, an exhaust diffuser 3, and a barrel-shaped member 5.

The exhaust pipe 2 has a cylindrical shape. Although not shown, the upstream end of the exhaust pipe 2 is connected to an exhaust manifold provided in the internal combustion engine. The downstream end of the exhaust pipe 2 is open, and the exhaust diffuser 3 is provided at the downstream end of the exhaust pipe 2. Although not shown, the exhaust diffuser 3 is fixed to the exhaust pipe 2 via a predetermined holding member.

The exhaust diffuser 3 has a cylindrical shape in which the diameter is gradually increased from the upstream side to the downstream side.

Between the inner peripheral surface of the upstream end of the exhaust diffuser 3 and the outer peripheral surface of the downstream end of the exhaust pipe 2, for example, an outside air introduction port for introducing outside air such as running wind into the exhaust diffuser 3. 4 is provided.

The barrel-shaped member 5 is a barrel-shaped three-dimensional object. The barrel-shaped member 5 is provided in the exhaust pipe 2 so as to reduce the area of the opening portion at the downstream end of the exhaust pipe 2. For example, the barrel-shaped member 5 is held by a holding member (not shown) provided inside the exhaust pipe 2, outside the exhaust pipe 2, or inside the exhaust diffuser 3.

Further, the barrel-shaped member 5 is arranged so that a flow path 6 through which exhaust gas flows is provided between the outer peripheral surface of the barrel-shaped member 5 and the inner peripheral surface of the exhaust pipe 2. In FIG. 1, as an example, the width of the flow path 6 is constant (uniform).

The barrel-shaped member 5 has an upstream side portion 5a and a downstream side portion 5b.

The upstream side portion 5a has a shape in which the cross-sectional area in the radial direction gradually increases from the upstream side to the downstream side. In other words, the upstream side portion 5a has a shape in which the diameter gradually increases from the upstream side to the downstream side. Therefore, as shown in FIG. 1, the cross-sectional shape of the upstream side portion 5a in the axial direction is trapezoidal.

The downstream side portion 5b has a shape in which the cross-sectional area in the radial direction gradually decreases from the upstream side to the downstream side. In other words, the downstream side portion 5b has a shape in which the diameter gradually decreases from the upstream side to the downstream side. Therefore, as shown in FIG. 1, the cross-sectional shape of the downstream side portion 5b in the axial direction is trapezoidal.

Further, the barrel-shaped member 5 is provided so that the downstream end surface of the downstream side portion 5b (which may be referred to as the barrel-shaped member 5) does not protrude from the opening portion of the downstream end portion of the exhaust pipe 2.

The exhaust pipe 2 has a diameter-expanded portion 2a and a diameter-reduced portion 2b.

The enlarged diameter portion 2a is a portion facing the outer peripheral surface of the upstream side portion 5a of the barrel-shaped member 5. The inner diameter of the enlarged diameter portion 2a (the length in the vertical direction in FIG. 1) is expanded according to the shape of the upstream side portion 5a of the barrel-shaped member 5.

The reduced diameter portion 2b is a portion facing the outer peripheral surface of the downstream side portion 5b of the barrel-shaped member 5. The inner diameter of the reduced diameter portion 2b (the length in the vertical direction in FIG. 1) is reduced according to the shape of the downstream side portion 5b of the barrel-shaped member 5.

The configuration of the exhaust structure 1 has been described above.

Next, the gas flow in the exhaust structure 1 will be described with reference to FIG. In FIG. 1, the dotted arrow indicates the flow of the exhaust gas discharged from the internal combustion engine, and the solid arrow indicates the flow of the outside air.

Of the exhaust gas flowing in the exhaust pipe 2 along the axial direction, a part of the exhaust gas flows into the flow path 6 without colliding with the barrel-shaped member 5. On the other hand, the remaining exhaust gas, after colliding with the barrel-shaped member 5, flows along the radial direction of the barrel-shaped member 5 and flows into the flow path 6. Then, the exhaust gas flows into the exhaust diffuser 3 after flowing through the flow path 6.

The exhaust gas that has flowed into the exhaust diffuser 3 is mixed with the outside air that has flowed into the exhaust diffuser 3 from the outside air introduction port 4. After that, the exhaust gas is discharged into the atmosphere from the lower end of the exhaust diffuser 3.

The gas flow in the exhaust structure 1 has been described above.

As described in detail so far, in the present embodiment, the flow velocity of the exhaust gas can be increased by passing the exhaust gas through the flow path 6. As a result, the outside air from the outside air introduction port 4 is easily drawn into the exhaust diffuser 3. Therefore, it is possible to promote the mixing of the exhaust gas and the outside air in the exhaust diffuser 3. Therefore, according to the exhaust structure 1, the cooling performance of the exhaust gas can be further improved.

Further, in the present embodiment, the upstream side flow path of the flow path 6 (the flow path between the outer peripheral surface of the upstream side portion 5a of the barrel-shaped member 5 and the inner peripheral surface of the enlarged diameter portion 2a of the exhaust pipe 2). ) Flows through the exhaust gas, so that the flow velocity of the exhaust gas can be increased while reducing the increase in the exhaust pressure. The decrease in the increase in exhaust pressure can contribute to the suppression of the load on other in-vehicle parts.

Further, in the present embodiment, the downstream flow path of the flow path 6 (the flow path between the outer peripheral surface of the downstream side portion 5b of the barrel-shaped member 5 and the inner peripheral surface of the reduced diameter portion 2b of the exhaust pipe 2). ) Flows through the exhaust gas, so that the exhaust gas can be easily guided to the central portion in the exhaust diffuser 3, and the mixing of the exhaust gas and the outside air can be promoted. As a result, the cooling performance of the exhaust gas is improved.

Further, in the present embodiment, the reduced diameter portion 2b of the exhaust pipe 2 is reduced in diameter according to the shape of the downstream side portion 5b of the barrel-shaped member 5, so that the exhaust diffuser 3 attached to the reduced diameter portion 2b is attached. As a result, a smaller one (those with a smaller inner diameter) can be adopted. Therefore, space saving in the vehicle can be realized.

Further, in the present embodiment, since the exhaust diffuser 3 whose diameter is gradually increased from the upstream side to the downstream side is used, the exhaust gas can be diffused and discharged into the atmosphere. Therefore, the temperature of the exhaust gas discharged into the atmosphere can be further lowered, and the air volume of the exhaust gas can be reduced.

The present disclosure is not limited to the above-described embodiment, and can be appropriately modified and implemented without departing from the spirit of the present disclosure. Hereinafter, a modified example will be described.

[Modification 1]
In the embodiment, the case where the exhaust diffuser 3 whose diameter is gradually increased from the upstream side to the downstream side is used has been described as an example, but the present invention is not limited to this.

The configuration of the exhaust structure 1 according to this modification will be described with reference to FIG. FIG. 3 is a schematic cross-sectional view showing a configuration example of the exhaust structure 1 of this modified example. In FIG. 3, the flow of the exhaust gas and the outside air is the same as the flow of the exhaust gas and the outside air shown in FIG. 1, so the arrow is not shown.

As shown in FIG. 3, the exhaust structure 1 of this modification includes an exhaust diffuser 7 instead of the exhaust diffuser 3 shown in FIGS. 1 and 2.

As shown in FIG. 3, the exhaust diffuser 7 has an upstream side portion 7a, a central portion 7b, and a downstream side portion 7c. The upstream side portion 7a, the central portion 7b, and the downstream side portion 7c each have a cylindrical shape.

The inner diameter of each of the upstream side portion 7a and the downstream side portion 7c (the length in the vertical direction in FIG. 3) is larger than the inner diameter of the central portion 7b. That is, the exhaust diffuser 7 has an enlarged diameter on the upstream side and the downstream side.

By providing the upstream side portion 7a having an expanded diameter, the exhaust diffuser 7 can increase the flow velocity of the gas in the exhaust diffuser 7, and can further promote the mixing of the exhaust gas and the outside air in the central portion 7b. Further, the exhaust diffuser 7 is provided with the downstream side portion 7c having an enlarged diameter, so that the exhaust gas can be diffused and discharged into the atmosphere.

Instead of the exhaust diffuser 3 shown in FIGS. 1 and 2 and the exhaust diffuser 7 shown in FIG. 3, a cylindrical exhaust diffuser having a uniform inner diameter in the axial direction may be used. However, it is preferable to use the exhaust diffuser 3 or the exhaust diffuser 7 in order to obtain an exhaust gas diffusion effect or the like.

[Modification 2]
In the embodiment, the case where the width (which may be referred to as the diameter; the same applies hereinafter) of the flow path 6 is constant has been described as an example, but the present invention is not limited to this.

For example, in the flow path 6, the width of the flow path on the upstream side may be larger than the width of the flow path on the downstream side. The upstream flow path referred to here is, for example, the outer peripheral surface of the upstream side portion 5a of the barrel-shaped member 5 and the inner peripheral surface of the enlarged diameter portion 2a of the exhaust pipe 2 in the flow path 6 shown in FIG. The flow path between. Further, the downstream flow path referred to here is, for example, the outer peripheral surface of the downstream side portion 5b of the barrel-shaped member 5 and the inner circumference of the reduced diameter portion 2b of the exhaust pipe 2 in the flow path 6 shown in FIG. It is a flow path between the surface and the surface.

[Modification 3]
In the embodiment, the barrel-shaped member 5 is provided so that the downstream end face of the downstream side portion 5b (which may be referred to as the barrel-shaped member 5) does not protrude from the opening portion of the downstream end portion of the exhaust pipe 2. The case has been described as an example, but the present invention is not limited to this.

For example, the barrel-shaped member 5 may be provided so that the downstream end surface of the downstream side portion 5b projects from the opening portion of the downstream end portion of the exhaust pipe 2. As a result, the exhaust gas can be more easily guided to the central portion in the exhaust diffuser 3, and the mixing of the exhaust gas and the outside air can be further promoted. As a result, the cooling performance of the exhaust gas is further improved.

The modified example has been described above. In addition, each modification may be combined appropriately.

The exhaust structure of the present disclosure is useful for all techniques for discharging exhaust gas into the atmosphere.

1 Exhaust structure 2 Exhaust pipe 2a Expanded diameter 2b Reduced diameter 3 Exhaust diffuser 4 Outside air inlet 5 Barrel-shaped member 5a Upstream side 5b Downstream side 6 Flow path 7 Exhaust diffuser 7a Upstream side 7b Central part 7c Downstream side

Claims (9)

It has an exhaust pipe through which exhaust gas flows and an exhaust diffuser provided on the downstream side of the exhaust pipe, and has an exhaust structure in which the exhaust gas is mixed with outside air in the exhaust diffuser and discharged into the atmosphere.
It has a three-dimensional object arranged in the exhaust pipe so as to reduce the area of the opening portion at the downstream end of the exhaust pipe.
The three-dimensional object is
It is arranged so that a flow path through which the exhaust gas flows is provided between the outer peripheral surface of the three-dimensional object and the inner peripheral surface of the exhaust pipe.
Exhaust structure. The three-dimensional object is
It has an upstream side that gradually expands in diameter from the upstream side to the downstream side.
The exhaust structure according to claim 1. The exhaust pipe
It is a portion facing the outer peripheral surface of the upstream side portion of the three-dimensional object, and has a diameter-expanded portion whose inner diameter is expanded according to the shape of the upstream side portion of the three-dimensional object.
The exhaust structure according to claim 1 or 2. The three-dimensional object is
It has a downstream part whose diameter is gradually reduced from the upstream side to the downstream side.
The exhaust structure according to any one of claims 1 to 3. The exhaust pipe
It is a portion facing the outer peripheral surface of the downstream side portion of the three-dimensional object, and has a reduced diameter portion whose inner diameter is reduced according to the shape of the downstream side portion of the three-dimensional object.
The exhaust structure according to claim 4. Of the above-mentioned flow paths, the width of the upstream side flow path is larger than the width of the downstream side flow path.
The exhaust structure according to any one of claims 1 to 5. The downstream end face of the three-dimensional object is
Protruding from the opening at the downstream end of the exhaust pipe,
The exhaust structure according to any one of claims 1 to 6. The exhaust diffuser is
The shape gradually increases from the upstream side to the downstream side.
The exhaust structure according to any one of claims 1 to 7. The exhaust diffuser is
The upstream side portion and the downstream side portion of the exhaust diffuser have a shape in which the diameter is larger than that of the central portion.
The exhaust structure according to any one of claims 1 to 7.

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