Connecting pipe

Abstract

To improve flexibility of arrangement of a connection pipe while suppressing closing of the connection pipe.SOLUTION: A connection pipe 100 connects an exhaust passage 10 in which a filter for collecting particulate matters in exhaust gas is provided and a differential pressure sensor 30 to each other. The connection pipe 100 includes: a first piping part 20 located on an upstream side to which exhaust gas flows in from the exhaust passage 10 and having a first inner diameter 60; and a second piping part 22 located on an exhaust gas downstream side of the first piping part 20, having a second inner diameter 62 larger than the first inner diameter 60 and fixed to an exhaust manifold 12 by a fixation part 40.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a connecting pipe. [Background technology]

[0002] In order to comply with recent exhaust gas regulations, gasoline-powered vehicles are increasingly incorporating GPFs (Gasoline Particulate Filters) into their exhaust pipes. GPFs are filters that reduce the amount of particulate matter (PM) in exhaust gas to the PN (Particulate Number: PM particle number) regulation value. PM collection filters, including GPFs, become clogged with trapped PM. Therefore, when a filter becomes clogged, the filter is heated to burn the trapped PM and regenerate it. A known method for determining filter clogging is to detect the differential pressure of exhaust gas before and after the filter and compare the detected value with a specified value.

[0003] A known configuration is to connect an exhaust pipe and a differential pressure sensor with a connecting pipe to detect the differential pressure of exhaust gas before and after a filter. Moisture in the gas inside the connecting pipe condenses, forming water droplets inside the connecting pipe. These water droplets may freeze and clog the connecting pipe. If the connecting pipe becomes clogged, it may be impossible to accurately determine whether the filter is clogged. Therefore, a connecting pipe is known that has a guide groove on its inner wall that can guide moisture to prevent the inside of the connecting pipe from freezing (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2022-56782 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the connecting pipe described in Patent Document 1 tends to be thick because of the guide grooves provided on the inner wall, which increases the rigidity of the connecting pipe and places greater restrictions on its handling.

[0006] The present invention has been made in view of the above-mentioned problems, and has an object to improve the degree of freedom in handling the connecting pipe while suppressing clogging of the connecting pipe. [Means for solving the problem]

[0007] The present invention provides a connecting pipe that connects an exhaust path provided with a filter that captures particulate matter in exhaust gas to a differential pressure sensor, the connecting pipe being located upstream of the exhaust path into which the exhaust gas flows, the connecting pipe having a first inner diameter. a first end portion of the exhaust passage connected to the exhaust path, and a metal member bent upward in the direction of gravity between the first end portion and the second end portion of the exhaust passage, with the second end portion facing upward in the direction of gravity; a first piping section; and a second inner diameter located downstream of the first piping section in the exhaust gas flow direction, the second inner diameter being larger than the first inner diameter. a third end portion of the second piping portion connected to the first piping portion in the direction of gravity; Fixed to the exhaust manifold by the fixing part Made of metal and a second piping section.

[0008] In the above configuration, The second piping section is bent between the third end and the other fourth end, and is fixed to the exhaust manifold by the fixing section at a bent end on the fourth end side, and the bent section between the third end and the fourth end of the second piping section is located closer to the exhaust path than the bent section between the first end and the second end of the first piping section. It can be configured as follows.

[0009] In the above configuration, the fixing portion may be a metal bracket. [Effects of the Invention]

[0010] According to the present invention, it is possible to improve the degree of freedom in handling the connecting pipe while suppressing clogging of the connecting pipe. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a view illustrating the vicinity of a connecting pipe according to an embodiment. [Figure 2] FIG. 2(a) is a diagram illustrating a connecting pipe according to an embodiment, FIG. 2(b) is a cross-sectional view of a first piping section constituting the connecting pipe according to the embodiment, FIG. 2(c) is a cross-sectional view of a second piping section, and FIG. 2(d) is a cross-sectional view of a third piping section. [Figure 3]FIG. 3(a) is a diagram illustrating a connecting pipe according to a comparative example, FIG. 3(b) is a cross-sectional view of a first piping section constituting the connecting pipe according to the comparative example, and FIG. 3(c) is a cross-sectional view of a second piping section. [Figure 4] FIG. 4(a) is a diagram illustrating a problem that occurs in a connecting pipe according to a comparative example, and FIG. 4(b) is an enlarged view of region A in FIG. 4(a). [Figure 5] FIG. 5(a) is a diagram illustrating the effect of the connecting pipe according to the embodiment, and FIG. 5(b) is an enlarged view of region A in FIG. 5(a). DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present invention will be described with reference to the drawings. [Example]

[0013] Fig. 1 is a diagram illustrating the vicinity of a connecting pipe 100 according to an embodiment. As shown in Fig. 1, the connecting pipe 100 is a pipe that connects an exhaust path 10 and a differential pressure sensor 30. The exhaust path 10 is for discharging exhaust gas emitted from the engine to the outside, and is formed to include an exhaust manifold 12 and an exhaust pipe 14. The exhaust gas emitted from the engine flows from the exhaust manifold 12 into the exhaust pipe 14, as indicated by arrow F.

[0014] A filter 16 for capturing PM is installed in the exhaust pipe 14. The filter 16 is, for example, a GPF. In a GPF, when exhaust gas passes through the porous walls between cells, PM in the exhaust gas is deposited on the surface of the porous walls and captured. If the filter 16 becomes clogged with the captured PM, the filter 16 is regenerated by raising the temperature of the filter 16 and burning the captured PM.

[0015] Clogging of filter 16 is determined, for example, by detecting the differential pressure between the pressure of the exhaust gas before it passes through filter 16 and the atmospheric pressure, and comparing the detected value with a specified value. For this purpose, exhaust path 10 and differential pressure sensor 30 are connected by a connecting pipe 100. Connecting pipe 100 is connected to exhaust path 10 at a location that is upstream of filter 16 with respect to the flow F of exhaust gas. Therefore, exhaust gas before it passes through filter 16 flows from exhaust path 10 into connecting pipe 100.

[0016] The differential pressure sensor 30 measures the pressure of the exhaust gas upstream of the filter 16 via the connecting pipe 100, and also measures the atmospheric pressure, thereby detecting the differential pressure between the exhaust gas pressure and the atmospheric pressure. The output of the differential pressure sensor 30 is input to an ECU (Engine Control Unit) 50. The ECU 50 determines that the filter 16 is clogged when the detected value output by the differential pressure sensor 30 is equal to or greater than a specified value. When the ECU 50 determines that the filter 16 is clogged, it regenerates the filter 16, for example, by supplying unburned fuel gas to the filter 16 while the engine is running, thereby raising the temperature of the filter 16 and burning the PM.

[0017] As described above, exhaust gas flows into the connecting pipe 100 from the exhaust path 10. The connecting pipe 100 includes, in order from upstream to downstream with respect to the flow of exhaust gas flowing in from the exhaust path 10, a first piping section 20, a second piping section 22, and a third piping section 24. The first piping section 20 is connected to the exhaust path 10. The third piping section 24 is connected to a differential pressure sensor 30. The second piping section 22 between the first piping section 20 and the third piping section 24 is fixed to the exhaust manifold 12 by a fixing section 40, which is a bracket or the like made of a metal such as steel, stainless steel, aluminum, or copper.

[0018] The second piping section 22 is located higher in the direction of gravity than the first piping section 20. The first piping section 20 is bent upward in the direction of gravity at a bend 21 and then connected to the second piping section 22. The second piping section 22 is bent at a bend 23 and is fixed to the exhaust manifold 12 at the end of the bend by a fixing section 40. The bend 23 of the second piping section 22 is located closer to the exhaust manifold 12 than the bend 21 of the first piping section 20.

[0019] FIG. 2(a) is a diagram illustrating a connecting pipe 100 according to an embodiment, FIG. 2(b) is a cross-sectional view of a first pipe section 20 constituting the connecting pipe 100, FIG. 2(c) is a cross-sectional view of a second pipe section 22, and FIG. 2(d) is a cross-sectional view of a third pipe section 24. As shown in FIGS. 2(a) to 2(d), the first pipe section 20 has an inner diameter 60 from one end to the other. The inner diameter 60 of the first pipe section 20 is relatively small. Therefore, the rigidity of the first pipe section 20 is relatively low. The inner diameter 60 of the first pipe section 20 is, for example, 6.35 cm.

[0020] The second piping section 22 has an inner diameter 62 from one end to the other. The inner diameter 62 of the second piping section 22 is larger than the inner diameter 60 of the first piping section 20. For example, the inner diameter 62 of the second piping section 22 is 8.00 cm, which is approximately 1.25 times the inner diameter 60 of the first piping section 20. Because the inner diameter 62 of the second piping section 22 is large, even if moisture contained in the gas inside the second piping section 22 condenses to generate water droplets, as will be described later, the water droplets are more likely to flow off, and the accumulation of water droplets in the second piping section 22 is suppressed.

[0021] The third piping section 24 has an inner diameter 64 from one end to the other. The inner diameter 64 of the third piping section 24 is larger than the inner diameter 62 of the second piping section 22. The inner diameter 64 of the third piping section 24 is, for example, 1.2 to 2.0 times the inner diameter 62 of the second piping section 22. The first piping section 20 and the second piping section 22 are connected by a first connection piping section 26 having an expanded pipe structure, and the second piping section 22 and the third piping section 24 are connected by a second connection piping section 28 having an expanded pipe structure. The first piping section 20, the second piping section 22, the third piping section 24, the first connection piping section 26, and the second connection piping section 28 are formed, for example, from the same material, such as steel, stainless steel, aluminum, or copper.

[0022] As shown in FIG. 1, the second piping section 22 is fixed to the exhaust manifold 12 by the fixing section 40, and therefore the connecting pipe 100 has the second piping section 22, which has an inner diameter 62 larger than that of the first piping section 20 connected to the exhaust path 10, fixed to the exhaust manifold 12 by the fixing section 40.

[0023] [Comparative Example] FIG. 3(a) illustrates a connecting pipe 500 according to a comparative example, FIG. 3(b) is a cross-sectional view of a first piping section 510 constituting the connecting pipe 500, and FIG. 3(c) is a cross-sectional view of a second piping section 512. As shown in FIGS. 3(a) to 3(c), the connecting pipe 500 according to the comparative example includes a first piping section 510 connected to the exhaust path 10 and a second piping section 512 connected to the differential pressure sensor 30. The first piping section 510 and the second piping section 512 are connected by a connecting piping section 514 having an expanded pipe structure. The inner diameter 516 of the first piping section 510 is relatively small. The inner diameter 516 of the first piping section 510 is the same size as the inner diameter 60 of the first piping section 20 in FIG. 2(b), for example. The inner diameter 518 of the second piping section 512 is larger than the inner diameter 516 of the first piping section 510. 2(d), for example. In other words, the connecting pipe 500 according to the comparative example does not have a portion corresponding to the second pipe section 22 of the connecting pipe 100 according to the example, and the portion corresponding to the second pipe section 22 is the first pipe section 510.

[0024] FIG. 4(a) illustrates a problem that occurs in the connecting pipe 500 according to the comparative example, and FIG. 4(b) is an enlarged view of region A in FIG. 4(a). As shown in FIG. 4(a), in the connecting pipe 500 according to the comparative example, region X of the first piping section 510, located upstream of where exhaust gas flows from the exhaust path 10, becomes relatively hot, whereas region Y, located downstream of region X, becomes colder than region X. Therefore, as shown in FIG. 4(b), moisture contained in the gas inside the first piping section 510 may condense in region Y of the first piping section 510, forming water droplets 70. If the water droplets 70 form in region Y of the first piping section 510 and remain there, for example, when the outside air temperature is low, the water droplets 70 may freeze and clog the connecting pipe 500. Here, because the inner diameter 516 of the first piping section 510 is relatively small, the water droplets 70 that form on the inner wall of the first piping section 510 are likely to come into contact with the inner wall on the opposite side. When the water droplets 70 adhere to both of the opposing inner walls of the first piping section 510, the entire water droplets 70 are supported by the inner walls of the first piping section 510 due to surface tension, and the water droplets 70 tend to remain in place. Therefore, the water droplets 70 generated in the region Y of the first piping section 510 tend to remain in place. For this reason, the water droplets 70 may freeze in the region Y of the first piping section 510, causing the connecting pipe 500 to become clogged. If the connecting pipe 500 becomes clogged, the differential pressure sensor 30 may not be able to accurately measure the pressure of the exhaust gas upstream of the filter 16, and as a result, it may not be possible to accurately determine whether the filter 16 is clogged.

[0025] FIG. 5(a) illustrates the effect of the connecting pipe 100 according to the embodiment, and FIG. 5(b) is an enlarged view of region A in FIG. 5(a). As shown in FIG. 5(a), in the connecting pipe 100 according to the embodiment, the first pipe section 20, which is located upstream of the exhaust gas flowing from the exhaust path 10, becomes relatively hot, whereas the second pipe section 22, which is located downstream of the first pipe section 20 in the exhaust gas flow direction, becomes colder than the first pipe section 20. As a result, moisture contained in the gas in the second pipe section 22 may condense and generate water droplets 70 in the second pipe section 22. Here, the inner diameter 62 of the second pipe section 22 is larger than the inner diameter 60 of the first pipe section 20, for example, 1.25 times larger. As a result, as shown in FIG. 5(b), water droplets 70 formed on the inner wall of the second pipe section 22 fall by their own weight before they grow large enough to contact the inner wall on the opposite side, thereby preventing the water droplets 70 from accumulating in the second pipe section 22. Therefore, even when the outside air temperature is low, for example, the water droplets 70 are prevented from freezing, and the connecting pipe 100 is prevented from being blocked. In order to prevent the water droplets 70 from remaining in the second piping section 22, the inner diameter 62 of the second piping section 22 is preferably at least 1.2 times the inner diameter 60 of the first piping section 20, more preferably at least 1.4 times, and even more preferably at least 1.6 times. On the other hand, if the second piping section 22 becomes thicker, its rigidity increases and it becomes difficult to handle, so the inner diameter 62 of the second piping section 22 is preferably at most 2.0 times the inner diameter 60 of the first piping section 20, more preferably at most 1.8 times, and even more preferably at most 1.6 times.

[0026] Furthermore, because the inner diameter 60 of the first piping section 20 is smaller than the inner diameter 62 of the second piping section 22, the rigidity of the first piping section 20 is reduced, improving the degree of freedom in handling the first piping section 20. Therefore, even in the case of a layout in which a component 80 is disposed beside the connecting pipe 100 as shown in Fig. 5(a), it is easy to handle the first piping section 20 by bending it to avoid the component 80.

[0027] 1, the second piping section 22 of the connecting pipe 100 is fixed to the exhaust manifold 12 by a thermally conductive fixing section 40. This makes it easier for heat from the exhaust manifold 12 to be transferred to the second piping section 22, thereby increasing the temperature of the second piping section 22. Therefore, even if moisture contained in the gas condenses in the second piping section 22 to generate water droplets 70 that remain in place, the water droplets 70 are prevented from freezing.

[0028] As described above, according to this embodiment, the connecting pipe 100 connecting the exhaust path 10 and the differential pressure sensor 30 includes the first pipe section 20 and the second pipe section 22. The first pipe section 20 is located upstream of the exhaust gas flow from the exhaust path 10 and has an inner diameter 60 (first inner diameter). The second pipe section 22 is located downstream of the exhaust gas flow from the first pipe section 20 and has an inner diameter 62 (second inner diameter) larger than the inner diameter 60 of the first pipe section 20. Because the inner diameter 62 of the second pipe section 22 is large, even if water droplets 70 are generated in the second pipe section 22, the water droplets 70 tend to fall due to their own weight, thereby preventing the water droplets 70 from accumulating in the second pipe section 22. This prevents the connecting pipe 100 from becoming clogged. The small inner diameter 60 of the first pipe section 20 improves the flexibility of the routing of the connecting pipe 100. Therefore, even when the component 80 is disposed to the side of the exhaust path 10, there are fewer restrictions on the shape of the component 80. Furthermore, the second piping section 22 is fixed to the exhaust manifold 12 by the fixing section 40. Because the exhaust manifold 12 becomes hot, fixing the second piping section 22 to the exhaust manifold 12 makes it possible to increase the temperature of the second piping section 22. Therefore, even if moisture contained in the gas in the second piping section 22 condenses to generate water droplets 70 that remain in place, it is possible to prevent the water droplets 70 from freezing.

[0029] Furthermore, in this embodiment, the second piping section 22 is located above the first piping section 20 in the direction of gravity. This makes it easier for water droplets 70 generated in the second piping section 22 to fall to the first piping section 20 due to their own weight. The first piping section 20 is located upstream of the exhaust gas flowing in from the exhaust path 10, and therefore reaches a relatively high temperature, so the water droplets 70 that fall from the second piping section 22 are heated and begin to evaporate.

[0030] In this embodiment, the fixing portion 40 that fixes the second piping portion 22 to the exhaust manifold 12 is a metal bracket. This makes it easier for heat from the exhaust manifold 12 to be transferred to the second piping portion 22 via the fixing portion 40, making it easier for the temperature of the second piping portion 22 to rise.

[0031] Furthermore, because the second piping section 22 is fixed to the exhaust manifold 12 by the fixing section 40, stress due to, for example, engine vibration is more likely to be applied to the second piping section 22. The second piping section 22 is thicker than the first piping section 20, and therefore has higher vibration resistance than the first piping section 20. Therefore, even if stress due to engine vibration is concentrated on the second piping section 22, damage to the second piping section 22 is suppressed. Furthermore, because the first piping section 20 is thinner than the second piping section 22, it has lower rigidity than the second piping section 22. Therefore, if contraction occurs in the exhaust manifold 12 and the exhaust pipe 14 that constitute the exhaust path 10 due to cold or heat, the first piping section 20 connected to the exhaust path 10 can deform and absorb the stress due to the contraction.

[0032] 1, the first piping section 20 is bent upward in the direction of gravity at a bent portion 21 and connected to the second piping section 22. The second piping section 22 is bent at a bent portion 23 and is fixed to the exhaust manifold 12 at the end of the bend by a fixing portion 40. The bent portion 23 of the second piping section 22 is located closer to the exhaust path 10 than the bent portion 21 of the first piping section 20. As a result, the bent portion 23 of the second piping section 22 receives heat from the exhaust path 10 and its temperature rises, making it difficult for water droplets 70 to freeze in the second piping section 22.

[0033] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and variations are possible within the scope of the gist of the present invention as defined in the claims. [Explanation of symbols]

[0034] 10...exhaust path, 12...exhaust manifold, 14...exhaust pipe, 16...filter, 20...first piping section, 21...bend section, 22...second piping section, 23...bend section, 24...third piping section, 26...first connecting piping section, 28...second connecting piping section, 30...differential pressure sensor, 40...fixing section, 50...ECU, 60, 62, 64...inner diameter, 70...water droplet, 80...part, 100...connecting pipe, 500...connecting pipe, 510...first piping section, 512...second piping section, 514...connecting piping section, 516, 518...inner diameter

Claims

1. A connecting pipe connecting an exhaust path provided with a filter that captures particulate matter in exhaust gas and a differential pressure sensor, a first piping section made of metal, the first piping section being located upstream of the exhaust gas flowing in from the exhaust path, the first piping section having a first inner diameter, one first end connected to the exhaust path, and bent upward in the direction of gravity between the first end and the other second end such that the second end faces upward in the direction of gravity; a second piping section made of metal, located downstream of the first piping section in the exhaust gas direction, having a second inner diameter larger than the first inner diameter, located above the first piping section in the direction of gravity, one third end connected to the second end, and fixed to the exhaust manifold by a fixing section.

2. The second piping section is bent between the third end and the other fourth end, and is fixed to the exhaust manifold by the fixing section at the bent end on the fourth end side; 2. The connecting pipe according to claim 1, wherein a bent portion between the third end and the fourth end of the second piping section is located closer to the exhaust path than a bent portion between the first end and the second end of the first piping section.

3. The connecting pipe according to claim 1 or 2, wherein the fixing portion is a metal bracket.

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