JP2021050680A - Exhaust gas cooling device - Google Patents

Abstract

To provide an exhaust gas cooling device capable of sufficiently lowering the temperature of exhaust gas.SOLUTION: An exhaust gas cooling device 1 includes a first exhaust pipe 2 through which exhaust gas G flows, a second exhaust pipe 3 connected to the first exhaust pipe 2 at its downstream side in the flowing direction of the exhaust gas G, an outside air introduction part 4 provided in a connection area between the first exhaust pipe 2 and the second exhaust pipe 3 for introducing outside air A into the second exhaust pipe 3, and a swirl flow generation part 5 provided in the second exhaust pipe 3. The first exhaust pipe 2 is constructed to exhaust all of the exhaust gas G introduced inside from the end on the downstream side, and the swirl flow generation part 5 having a blade member 52 is constructed to generate a swirl flow including the exhaust gas G exhausted from the first exhaust pipe 2 and the outside air A introduced from the outside air introduction part 4 using the blade member 52.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to an exhaust cooling device.

Conventionally, as disclosed in Patent Document 1, for example, a technique for cooling vehicle exhaust gas is known.

The configuration of Patent Document 1 includes an exhaust tail pipe and an outer cylinder that covers the exhaust tail pipe. Two opposing holes are provided on the side surface of the exhaust tail pipe. Plate-like bodies arranged so as to have a predetermined angle with respect to the side surface of the exhaust tail pipe are attached to these holes. In such a configuration, a part of the exhaust gas flowing through the exhaust tail pipe is bent by the plate-like body and flows out from the hole, and the rest goes straight as it is. When the exhaust gas flows out from the hole, the exhaust gas forms a swirling flow. Exhaust gas is cooled by mixing this swirling flow with the outside air that has flowed into the outer cylinder.

Jikkai Sho 61-183419

However, in the configuration as in Patent Document 1, there is a possibility that the temperature of the exhaust gas cannot be sufficiently lowered.

An object of the present disclosure is to provide an exhaust cooling device capable of sufficiently lowering the temperature of exhaust gas.

The exhaust cooling device according to the present disclosure includes a first exhaust pipe for flowing exhaust gas, a second exhaust pipe connected to the downstream side of the first exhaust pipe in the flow direction of the exhaust gas, and the above. It is provided at the connection portion between the first exhaust pipe and the second exhaust pipe, and is provided in the outside air introduction portion for introducing the outside air into the inside of the second exhaust pipe and in the second exhaust pipe. The first exhaust pipe includes a swirling flow generating portion, and the first exhaust pipe is configured to discharge all the exhaust gas guided to the inside from the downstream end portion, and the swirling flow generating portion is a blade. It has a member, and the blade member is configured to generate a swirling flow including the exhaust gas discharged from the first exhaust pipe and the outside air introduced from the outside air introduction portion.

According to the present disclosure, it is possible to provide an exhaust cooling device capable of sufficiently lowering the temperature of the exhaust gas.

Sectional drawing which shows schematic structure of the exhaust cooling apparatus which concerns on embodiment of this disclosure. The figure which looked at the exhaust cooling device which concerns on the portable of carrying out this disclosure from the downstream side of the exhaust gas flow.

Hereinafter, the exhaust cooling device according to the embodiment of the present disclosure will be described. In the following, the description of the configuration not related to the exhaust cooling device of the present disclosure will be omitted.

[Structure of exhaust cooling device]
First, the structure of the exhaust cooling device will be described. FIG. 1 is a cross-sectional view schematically showing the structure of an exhaust cooling device. FIG. 2 is a view of the exhaust cooling device viewed from the downstream side of the exhaust gas flow.

The exhaust cooling device 1 shown in FIG. 1 is arranged on the lower surface of a vehicle body of a vehicle (not shown). The exhaust cooling device 1 includes a first exhaust pipe 2, a second exhaust pipe 3, an outside air introduction unit 4, and a swirling flow generation unit 5.

The first exhaust pipe 2 is formed in a cylindrical shape. An internal combustion engine (not shown) is connected to the left end of FIG. 1 in the first exhaust pipe 2. The first exhaust pipe 2 is discharged from the internal combustion engine, and all the exhaust gas G guided into the inside of the first exhaust pipe 2 flows to the right in FIG. 1 and is discharged from the downstream end. In the following, the direction may be indicated with reference to the flow of the exhaust gas G, the "upstream side" represents the left side of FIG. 1, and the "downstream side" represents the right side of FIG.

The second exhaust pipe 3 is provided on the downstream side of the first exhaust pipe 2. The second exhaust pipe 3 includes a large diameter portion 31, a small diameter portion 32, and a connecting portion 33.

The large diameter portion 31 is formed in a cylindrical shape having an inner diameter larger than the outer diameter of the downstream portion of the first exhaust pipe 2. The large diameter portion 31 is provided so that the first flow path 41 is formed between the large diameter portion 31 and the outer peripheral surface 2B of the portion on the downstream side of the first exhaust pipe 2. As shown in FIG. 2, the large diameter portion 31 is fixed to the first exhaust pipe 2 via brackets 30 provided at three locations in the outer peripheral direction.

The small diameter portion 32 is formed in a cylindrical shape having an inner diameter smaller than the inner diameter of the large diameter portion 31. The small diameter portion 32 is provided so that a second flow path 42 is formed between the small diameter portion 32 and the downstream end portion of the first exhaust pipe 2.

The connecting portion 33 is formed in a truncated cone shape whose inner diameter decreases toward the downstream side, and has a large diameter so that the inner peripheral surface 31A of the large diameter portion 31 and the inner peripheral surface 32A of the small diameter portion 32 are continuous. The portion 31 and the small diameter portion 32 are connected.

The outside air introduction unit 4 is provided at a connection portion between the first exhaust pipe 2 and the second exhaust pipe 3, and introduces the outside air A into the inside of the second exhaust pipe 3. The outside air introduction unit 4 includes a first flow path 41 and a second flow path 42. The outside air introduction portion 4 is continuously provided over the entire circumferential direction of the first exhaust pipe 2.

The swirling flow generating portion 5 is provided inside the second exhaust pipe 3, specifically, at the upstream end portion of the small diameter portion 32. As shown in FIGS. 1 and 2, the swirling flow generating portion 5 includes a cylindrical shaft portion 51 and four blade members 52 provided on the outer peripheral surface of the shaft portion 51. In addition, in FIG. 1, in order to make it easy to distinguish between the blade member 52 and the inner peripheral surface of the second exhaust pipe 3, fine dots are attached to the surface of the blade member 52 facing the upstream side. The swirling flow generating portion 5 is fixed so that the shaft portion 51 is located at the radial center of the second exhaust pipe 3 and the central axis of the shaft portion 51 and the central axis of the second exhaust pipe 3 overlap. Has been done. The blade members 52 are provided at equal intervals along the outer peripheral direction of the shaft portion 51. As shown in FIG. 2, the blade member 52 is formed in a fan-shaped plate shape having a central angle of about 90 ° when viewed from the downstream side. The blade member 52 is provided so that the front end portion in the counterclockwise direction is located on the front side of the rear end portion when viewed from the downstream side. As a method of fixing the swirling flow generating portion 5 and the second exhaust pipe 3, a rod-shaped or plate-shaped connecting member (not shown) for connecting the outer peripheral surface of the shaft portion 51 and the inner peripheral surface of the second exhaust pipe 3 is formed. The blade member 52 and the inner peripheral surface of the second exhaust pipe 3 may be connected directly or via a connecting member (not shown). The swirling flow generating portion 5 and the second exhaust pipe 3 may be integrally molded.

[Exhaust gas cooling method]
Next, a method of cooling the exhaust gas in the exhaust cooling device 1 will be described.

When the exhaust gas G is discharged from the internal combustion engine as the vehicle travels, the exhaust gas G is guided to the first exhaust pipe 2. When the exhaust gas G flows through the first exhaust pipe 2, the first flow path 41 and the second flow path 42 constituting the outside air introduction unit 4 become negative pressure. Due to this negative pressure, the outside air A, which exists outside the exhaust cooling device 1 and has a temperature lower than that of the exhaust gas G, is guided to the inside of the exhaust cooling device 1 via the outside air introduction unit 4. The outside air A and the exhaust gas G discharged from the first exhaust pipe 2 are mixed by the swirling flow generating unit 5, and as shown in FIG. 2, the exhaust gas G mixed with the outside air A swivels in the right-handed screw direction. A flow is generated. In FIG. 2, when viewed from the downstream side, the exhaust gas G located in front of the blade member 52 is shown by a solid line, and the exhaust gas G located behind the blade member 52 is shown by a broken line. This swirling flow promotes mixing of the outside air A and the exhaust gas G, and the temperature of the exhaust gas G is further lowered. In particular, since all the exhaust gas G discharged from the internal combustion engine and guided to the inside of the first exhaust pipe 2 is mixed with the outside air A by the swirling flow, only a part of the exhaust gas of the exhaust tail pipe is mixed with the outside air. Compared with the configuration of the above-mentioned Patent Document 1, the temperature of the entire exhaust gas G is further lowered. Then, the exhaust gas G is discharged from the end portion 3C on the downstream side of the second exhaust pipe 3.

By lowering the temperature of the exhaust gas G discharged from the exhaust cooling device 1 in this way, it is possible to suppress an increase in the temperature of the road surface, deterioration of resin parts of the vehicle, failure of electronic parts, and the like. Further, since the swirling flow generating portion 5 is provided at the upstream end portion of the small diameter portion 32, that is, at the confluence portion between the exhaust gas G and the outside air A, the outside air A and the exhaust gas using the swirling flow are provided. Mixing with G can be performed in the vicinity of the first exhaust pipe 2. Therefore, the temperature of the exhaust gas G can be lowered without lengthening the entire second exhaust pipe 3.

[Modified example of the embodiment]
Needless to say, the present disclosure is not limited to that shown in the embodiments described above, and various modifications can be made without departing from the spirit of the present disclosure.

For example, the shaft portion 51 may be cylindrical. The number of blade members 52 constituting the swirling flow generating unit 5 may be five or more, three or two, or one as long as the swirling flow can be generated. However, from the viewpoint of minimizing the pressure loss of the outside air A and the exhaust gas G, it is preferable that the number of blade members 52 is small. The swirling flow generated by the swirling flow generating unit 5 may be in the left-hand thread direction. One swirling flow generating portion 5 may be provided on the downstream side of the second exhaust pipe 3 or may be provided in the center. Another swirl flow generation unit 5 may be provided on the downstream side of the swirl flow generation unit 5 shown in FIG. In this case, the swirling directions of the swirling flows generated by each swirling flow generating unit 5 may be the same or different. Although the plurality of blade members 52 are fixed to the outer peripheral surface of the shaft portion 51, the plurality of blade members 52 may be directly connected to each other. In addition, the shape of the constituent members of the swirling flow generating unit 5 is not limited to the shape of the above-described embodiment, and may be any shape as long as the swirling flow can be generated.

The configuration of the present disclosure can be applied to an exhaust cooling device.

1 Exhaust cooling device 2 1st exhaust pipe 2B outer peripheral surface 3 2nd exhaust pipe 3C end 4 outside air introduction part 5 swirling flow generating part 30 bracket 31 large diameter part 31A inner peripheral surface 32 small diameter part 32A inner peripheral surface 33 connection Part 41 First flow path 42 Second flow path 51 Shaft part 52 Blade member A Outside air G Exhaust gas

Claims (2)

The first exhaust pipe for flowing exhaust gas and
A second exhaust pipe connected to the downstream side in the flow direction of the exhaust gas in the first exhaust pipe, and
An outside air introduction portion provided at a connection portion between the first exhaust pipe and the second exhaust pipe for introducing outside air into the inside of the second exhaust pipe.
A swirling flow generating portion provided in the second exhaust pipe is provided.
The first exhaust pipe is configured to exhaust all the exhaust gas guided to the inside from the downstream end.
The swirling flow generating portion has a blade member, and the blade member generates a swirling flow including the exhaust gas discharged from the first exhaust pipe and the outside air introduced from the outside air introducing portion. Is configured to
Exhaust cooling device. The second exhaust pipe is
A large diameter is formed so that the inner diameter is larger than the outer diameter of the downstream portion of the first exhaust pipe and the first flow path is formed between the inner diameter and the outer peripheral surface of the downstream portion. Diameter and
The inner diameter is formed smaller than the inner diameter of the large diameter portion, and a second flow path is formed between the upstream end of the exhaust gas flow and the downstream end of the first exhaust pipe. With a small diameter part provided so as to
A connecting portion for connecting the large diameter portion and the small diameter portion is provided so that the inner peripheral surface of the large diameter portion and the inner peripheral surface of the small diameter portion are continuous.
The outside air introduction unit is configured to include the first flow path and the second flow path.
The swirling flow generating portion is provided at the upstream end portion of the small diameter portion.
The exhaust cooling device according to claim 1.

Images