Exhaust structure

Abstract

To provide an exhaust structure capable of suppressing water flowing in from the exhaust downstream side of a sensor from splashing onto the sensor. [Solution] In the exhaust structure according to the present invention, a shielding member 5 is provided at the lower inside portion of the exhaust pipe (catalytic converter case 21) facing the NOx sensor 4, extending downstream in the exhaust flow than the NOx sensor 4. This makes it possible to prevent the exhaust condensed water W from adhering to the NOx sensor 4, even if the exhaust condensed water W that accumulates in a puddle portion 30 is scattered from the downstream exhaust flow due to, for example, the vehicle running over a bump or sudden braking (not shown).

Description

[Technical Field]

[0001] The present invention relates to an exhaust structure. [Background technology]

[0002] A known conventional exhaust structure is, for example, that described in Patent Document 1 below.

[0003] In summary, this conventional exhaust structure has a partition member provided upstream of the sensor so as to face a water pool located upstream of the sensor, thereby preventing condensed water from the water pool from scattering onto the sensor. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-179190 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the conventional exhaust structure, the partition plate is formed as a plate extending parallel to the inner surface of the straight pipe section where the sensor is located, which makes it difficult to prevent water that flows in from downstream of the sensor from splashing onto the sensor, and there is still room for improvement.

[0006] Therefore, the present invention was devised in consideration of the technical problems of the conventional exhaust structure, and aims to provide an exhaust structure that can prevent water that flows in from the exhaust downstream side of the sensor from splashing onto the sensor. [Means for solving the problem]

[0007] In one aspect, the present invention comprises an element-type sensor provided on the inside upper part of an exhaust pipe, a puddle portion provided on the exhaust pipe downstream of the sensor in the exhaust direction, and a shielding member provided on the inside lower part of the exhaust pipe opposite the sensor, extending downstream of the sensor in the exhaust direction, and preventing water from splashing into the puddle portion onto the sensor. [Effects of the Invention]

[0008] According to the present invention, a shielding member is provided on the lower inside of the exhaust pipe facing the sensor, extending downstream in the exhaust direction from the sensor. This prevents the exhaust condensed water from adhering to the sensor even when water in the puddle (exhaust condensed water) is splashed from the downstream side of the exhaust due to, for example, vehicle behavior such as climbing up a bump or sudden braking. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is an enlarged perspective view of a muffler (exhaust pipe) to which an exhaust structure according to the present invention is applied. [Figure 2] FIG. 2 is a longitudinal perspective cross-sectional view of part A in FIG. 1. [Figure 3] 3 is a view taken along the arrow B in FIG. 2. [Figure 4] FIG. 4 is a cross-sectional view taken along line CC in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0010] An embodiment of the exhaust structure according to the present invention will be described in detail below with reference to the drawings. In this embodiment, as in the prior art, an example in which the exhaust structure according to the present invention is applied to a muffler (exhaust pipe) for an automobile is shown. In each drawing, Fr ​​indicates the front of the vehicle, which is the upstream side of the exhaust, and Rr indicates the rear of the vehicle, which is the downstream side of the exhaust.

[0011] FIG. 1 is a perspective view of the muffler 1 according to this embodiment as viewed from above, showing an enlarged view of the main part near the rear end of the catalytic converter 2. FIG. 2 is a perspective cross-sectional view of the muffler 1 taken along the longitudinal direction of part A in FIG. 1 and viewed obliquely from above. FIG. 3 is a view taken in the direction of the arrow B in FIG. 2, showing a vertical cross-sectional view of the muffler 1. FIG. 4 is a horizontal cross-sectional view of the muffler 1 taken along line CC in FIG. 3.

[0012] 1, for example, muffler 1 is connected to the downstream end of an exhaust manifold (not shown) connected to an engine (not shown) under the floor of an automobile body, and is arranged so as to extend along the front-to-rear direction of the vehicle body. Specifically, muffler 1 has a catalytic converter 2 connected to the exhaust manifold (not shown), and a tail pipe 3 which is a pipe portion connected to the rear end of this catalytic converter 2.

[0013] 2 to 4, the catalytic converter 2 has a generally cylindrical catalytic converter case 21 with a hollow interior, and the catalytic converter case 21 houses, for example, a three-way catalyst 22 (see FIG. 4). The rear end of the catalytic converter case 21 communicates with the tail pipe 3 at a vertically downward position, and the inner bottom surface 211a of the bottom wall 211 of the catalytic converter case 21 and the inner bottom surface 33 of the tail pipe 3 are configured to be continuous with almost no steps. Exhaust (exhaust gas) that flows into the catalytic converter 2 from the exhaust upstream side, which is the left side in each figure, flows to the exhaust downstream side (tail pipe 3 side), which is the right side in each figure.

[0014] Furthermore, a NOx sensor 4, which is an element-type sensor, is provided inside the catalytic converter case 21 at an upper end portion downstream of the three-way catalyst 22 (see FIG. 4) disposed in the longitudinal middle portion. The NOx sensor 4 is disposed so as to face the internal space of the catalytic converter case 21 via a through-hole 213 that passes vertically through an upper wall 212 of the catalytic converter case 21, and measures the NOx concentration in the exhaust gas flowing downstream of the three-way catalyst 22.

[0015] The tail pipe 3 is formed in a cylindrical shape with a generally constant inner diameter and a flow path cross-sectional area smaller than that of the catalytic converter case 21, and is curved obliquely upward from the connection point with the catalytic converter 2 toward the vehicle floor (not shown), which is vertically upward. In other words, the tail pipe 3 is formed so that a first end 31 on the exhaust upstream side, which connects to the catalytic converter 2, is the lowest. As a result, a pool 30 in which exhaust condensed water W (see FIG. 3) accumulates is formed near the first end 31 inside the tail pipe 3. Meanwhile, a flange joint 320 is integrally formed at a second end 32 of the tail pipe 3, which is the other end side of the first end 31, and the tail pipe 3 is connected to a main pipe (not shown) of the muffler 1 via this flange joint 320.

[0016] Furthermore, inside the catalytic converter case 21, a shielding member 5 is provided at the inner lower end of the catalytic converter case 21 facing the NOx sensor 4, extending further downstream in the exhaust gas than the NOx sensor 4. In this way, by providing the shielding member 5 extending further downstream in the exhaust gas than the NOx sensor 4, scattering of exhaust condensed water W (see FIG. 3) flowing in from the exhaust gas downstream side toward the NOx sensor 4 is suppressed.

[0017] The shielding member 5 is formed by bending a thin metal plate, and has a bulging portion 51 that bulges vertically upward, and a joint portion 52 that is provided on the periphery of the bulging portion 51 and is connected to the inner bottom surface 211a of the catalytic converter case 21. Specifically, the shielding member 5 is formed so that the upstream exhaust side is closed and the downstream exhaust side is open, and a water replenishing portion 50 that can replenish exhaust condensed water W (see FIG. 3) that flows in from the downstream exhaust side is formed inside the bulging portion 51. This makes it possible for the exhaust condensed water W that flows in from the tailpipe 3 side to be retained in the water replenishing portion 50.

[0018] The bulging portion 51 is set to a generally constant height so that the upper end portion thereof is flat and horizontal. In this embodiment, the height H1 of the bulging portion 51, which constitutes the height of the end portion on the downstream side of the exhaust gas, is set lower than the height H2 of the inner upper surface 34, which is the inner surface of the upper end portion of the tail pipe 3.

[0019] The joint portion 52 is provided on the peripheral edge of the bulging portion 51, excluding the end portion on the exhaust downstream side, and is continuously joined by welding to the inner bottom surface 211a of the catalytic converter case 21. As a result, the joint portion 52 is joined without any gaps to the inner circumferential surface of the lower end side, including the inner bottom surface 211a of the catalytic converter case 21, and leakage of the exhaust condensed water W (see FIG. 3) collected in the water replenishing portion 50 to the exhaust upstream side is suppressed. Note that the means for joining the shielding member 5 to the catalytic converter case 21 is not limited to welding, and can be changed as desired depending on the specifications of the muffler 1, etc.

[0020] Furthermore, a recess 53 is provided at the downstream end of the bulge 51 in the exhaust gas flow direction by recessing a portion of the bulge 51 toward the upstream side of the exhaust gas flow. The recess 53 is formed in a rectangular shape with a generally constant depth in the width direction. Here, it is desirable that an extension 54 extending at a downward incline is provided at the periphery of the recess 53. This makes it possible to straighten the exhaust gas passing above the bulge 51 and more effectively reduce the flow resistance of the exhaust gas. Note that the shape of the recess 53 is not limited to the rectangular shape exemplified in this embodiment, and can be changed as desired depending on the specifications of the muffler 1, etc.

[0021] (Effects of this embodiment) As described above, in the exhaust structure according to this embodiment, a shielding member 5 is provided at the lower inside portion of the exhaust pipe (catalytic converter case 21) facing the NOx sensor 4, extending downstream of the NOx sensor 4. This makes it possible to prevent the exhaust condensed water W from adhering to the NOx sensor 4, even if the exhaust condensed water W accumulated in the puddle portion 30 is scattered from the exhaust downstream side due to, for example, the vehicle running over a bump or sudden braking (not shown).

[0022] In addition, in this embodiment, the shielding member 5 is formed so that the exhaust upstream side is closed and the exhaust downstream side is open. This makes it possible to retain the exhaust condensed water W that flows in from the tail pipe 3 side within the water replenishing section 50. Furthermore, the exhaust condensed water W collected in the water replenishing section 50 can be discharged to the exhaust downstream side due to the negative pressure generated by the flow of exhaust gas. This makes it possible to more effectively prevent the exhaust condensed water W collected in the water replenishing section 50 from scattering toward the NOx sensor 4.

[0023] Furthermore, in this embodiment, the joint 52 provided on the peripheral edge of the shielding member 5 excluding the downstream exhaust end is joined to the inner bottom surface 211a of the catalytic converter case 21. This blocks the upstream exhaust side of the water replenishing section 50, making it possible to prevent the exhaust condensed water W collected in the water replenishing section 50 from leaking to the upstream exhaust side. This prevents the exhaust condensed water W collected in the water replenishing section 50 from leaking and scattering toward the NOx sensor 4, making it possible to more effectively prevent water from scattering toward the NOx sensor 4.

[0024] Furthermore, in this embodiment, the joint portion 52 of the shielding member 5 is joined by welding to the inner bottom surface 211a of the catalytic converter case 21. This makes it possible to join the joint portion 52 of the shielding member 5 to the inner bottom surface 211a of the catalytic converter case 21 without any gaps, effectively suppressing leakage of the exhaust condensed water W collected in the water replenishing portion 50. Furthermore, the use of welding has the advantage of making it possible to easily join the joint portion 52 of the shielding member 5 to the inner bottom surface 211a of the catalytic converter case 21.

[0025] Furthermore, in this embodiment, the bulging portion 51 is formed so that the height H1 of the end portion on the exhaust downstream side is lower than the height H2 of the inner upper surface 34 of the tail pipe 3. Therefore, even when the water replenishing portion 50 is full of water, there is no risk that the exhaust passage connecting the catalytic converter case 21 and the tail pipe 3 will be blocked by the shielding member 5. This makes it possible to suppress a decrease in output due to an increase in pressure loss that occurs when the exhaust condensed water W in the water replenishing portion 50 filled with water blocks the exhaust passage.

[0026] Furthermore, in this embodiment, the shielding member 5 is provided with a recess 53 at the downstream exhaust end of the bulging portion 51, which is formed by recessing a portion of the bulging portion 51 toward the upstream exhaust side. This recess 53 reduces the flow resistance of the exhaust gas passing above the bulging portion 51, thereby making it possible to suppress a decrease in engine output. Furthermore, the provision of the recess 53 has the advantage that exhaust condensed water W that flows in together with the exhaust gas from the upstream exhaust side can be smoothly discharged to the downstream exhaust side.

[0027] The present invention is not limited to the configurations exemplified in the above-described embodiments, and can be freely modified according to, for example, the specifications of the vehicle body (not shown) to which the present invention is applied and the muffler 1, etc.

[0028] In particular, the specific shape of the shielding member 5, and the arrangement and mounting means of the shielding member 5 are not limited to the forms exemplified in the above embodiment, and can be changed as desired depending on the layout of the underside of the vehicle floor (not shown) and the specifications of the muffler 1, etc. [Explanation of symbols]

[0029] 1... Muffler 2...Catalytic converter 21...Catalytic converter case 211a…Inner bottom surface 3...Tailpipe (pipe section) 30...Puddle area 4...NOx sensor (sensor) 5...Shielding member 51...bulge 52…Joint part 53...recess

Claims

1. an element-type sensor provided at an upper part inside the exhaust pipe; a pool portion provided in the exhaust pipe downstream of the sensor; a shielding member that is provided on an inner lower portion of the exhaust pipe so as to face the sensor, extends downstream of the exhaust gas flowing from the sensor, and prevents water from splashing onto the sensor; An exhaust structure equipped with

2. The exhaust structure according to claim 1, The sensor is disposed inside an upper portion of a catalytic converter case that houses a catalytic converter, the water pool is provided in a pipe section having a flow path cross-sectional area smaller than that of the catalytic converter case, The shielding member is disposed inside the catalytic converter case at a lower portion thereof so as to extend toward the pipe portion beyond the sensor.

3. The exhaust structure according to claim 2, An exhaust structure in which the shielding member is closed by being joined to the inner bottom surface of the catalytic converter case on the upstream side of the exhaust, and the downstream side of the exhaust is open to the pipe section side, forming a water-retaining section between the shielding member and the inner bottom surface of the catalytic converter case that can collect water that flows in from the pipe section side.

4. The exhaust structure according to claim 3, an exhaust structure in which the peripheral edge of the shielding member, excluding the downstream end of the shielding member, is joined to the inner surface of the catalytic converter case;

5. The exhaust structure according to claim 4, The peripheral edge is joined to the inner bottom surface of the catalytic converter case by welding.

6. The exhaust structure according to claim 4, the shielding member has a bulging portion that bulges vertically upward from the inner bottom surface of the catalytic converter case, An exhaust structure in which the height of the downstream end of the bulging portion is set lower than the inner surface of the upper end of the pipe portion.

7. 7. The exhaust structure according to claim 6, The shielding member has a recess at an end of the bulging portion on the downstream side of the exhaust gas flow, the recess being formed by recessing a part of the bulging portion toward the upstream side of the exhaust gas flow.

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