Exhaust purification apparatus for engine
By incorporating curved connecting pipes, gaps, and throttling sections between the catalytic converters, the problem of uneven exhaust flow is solved, resulting in improved exhaust purification performance, easier installation of the device, and enhanced detection accuracy of the gas sensor.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- TOYOTA JIDOSHA KK
- Filing Date
- 2025-11-20
- Publication Date
- 2026-06-26
AI Technical Summary
If the exhaust gas that has passed through the first catalytic converter flows unevenly into the second catalytic converter, the exhaust purification performance of the second catalytic converter may not be fully utilized, leading to a deterioration in exhaust emissions.
The first and second catalytic converters are connected by a connecting pipe with a curved central axis. The gap and throttling section are set to ensure uniform exhaust flow. A gas sensor is equipped to detect the exhaust status, and a throttling section is set in the connecting pipe to control the flow rate, ensuring that the exhaust flows uniformly into the second catalyst carrier.
The deterioration of exhaust emissions was suppressed, the detection accuracy of the gas sensor was improved, the purification performance of the second catalyst carrier was fully utilized, and the device was miniaturized and easy to install.
Smart Images
Figure CN122280692A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to an exhaust purification device for engines. Background Technology
[0002] There is an engine exhaust purification device having a first catalytic converter and a second catalytic converter disposed downstream of the first catalytic converter (for example, see Patent Document 1: WO2018 / 110324). Summary of the Invention
[0003] The technical problem that the invention aims to solve
[0004] If the exhaust gas from the first catalytic converter flows unevenly into the second catalytic converter, the exhaust purification performance of the second catalytic converter may not be fully utilized. This could lead to a deterioration in exhaust emissions.
[0005] Therefore, the present invention aims to provide an exhaust purification device for an engine that suppresses the deterioration of exhaust emissions.
[0006] The above objective can be achieved by an exhaust purification device for an engine comprising: a first catalytic converter including a first housing and a first catalyst carrier held within the first housing; a second catalytic converter located downstream of the first catalytic converter and including a second housing and a second catalyst carrier held within the second housing; a connecting pipe with a curved central axis connecting the first housing and the second housing; the first catalyst carrier having a downstream end face; the first housing having a downstream end protruding downstream from the downstream end face; the second catalyst carrier having an upstream end face; and a gap being provided between the downstream end face and the upstream end face in a direction perpendicular to the downstream end face.
[0007] It may also include a gas sensor installed on the connecting pipe to detect the state of exhaust gas. The connecting pipe has an upstream portion, a downstream portion, and a throttling portion (neck) located between the upstream portion and the downstream portion. The cross-sectional area perpendicular to the central axis at the throttling portion is smaller than the cross-sectional area perpendicular to the central axis at each of the upstream and downstream ends. The detection part of the gas sensor is located at the throttling portion.
[0008] Alternatively, a portion of the downstream end may be located in the throttling section, and the detection section of the gas sensor may face the downstream end face in a direction perpendicular to the downstream end face.
[0009] Alternatively, a portion of the first catalyst support may be located within the connecting tube.
[0010] Alternatively, the downstream end may overlap with the second housing in a direction parallel to the downstream end face.
[0011] Technical effect
[0012] According to the present invention, an exhaust purification device for an engine is provided that suppresses the deterioration of exhaust emissions. Attached Figure Description
[0013] Figure 1 This is an exterior view of the exhaust purification device.
[0014] Figure 2 This is a cross-sectional view of an exhaust purification device. Detailed Implementation
[0015] Figure 1 This is an external view of the exhaust purification device 1. The exhaust purification device 1 is disposed on the exhaust passage connected to the engine 100 to purify the exhaust gas from the engine 100. The exhaust purification device 1 and the engine 100 are disposed, for example, in the engine compartment of a vehicle. The engine 100 can be either a gasoline engine or a diesel generator. The exhaust purification device 1 includes a first catalytic converter 10, a second catalytic converter 30, and a connecting pipe 50.
[0016] The first catalytic converter 10 has a first housing 12 and a first catalyst support 14. The first catalyst support 14 holds the first housing 12. The first housing 12 is cylindrical. The first catalyst support 14 is cylindrical with an outer diameter smaller than the inner diameter of the first housing. The second catalytic converter 30 has a second housing 32 and a second catalyst support 34. The second catalyst support 34 holds the second housing 32. The second housing 32 is cylindrical. The second catalyst support 34 is cylindrical with an outer diameter smaller than the inner diameter of the second housing. The first catalytic converter 10 and the second catalytic converter 30 are arranged close to each other via a connecting pipe 50.
[0017] The first catalyst carrier 14 is, for example, a three-way catalyst with oxygen storage capacity that purifies NOx, HC, and CO. The second catalyst carrier 34 is, for example, a catalyst that promotes the combustion of particulate matter (hereinafter referred to as PM) in exhaust gas, carried in a filter. The upstream end 121 of the first housing 12 is connected to the exhaust pipe 91. The exhaust pipe 91 is connected to the engine 100 via an exhaust manifold on the upstream side. The downstream end 322 of the second housing 32 is connected to the exhaust pipe 92.
[0018] A connecting pipe 50 connects the first catalytic converter 10 and the second catalytic converter 30. The connecting pipe 50 is manufactured by stamping a metal sheet. An air-fuel ratio sensor 70 is provided in the connecting pipe 50. The air-fuel ratio sensor 70 is inserted into an opening in the connecting pipe 50. A detection part 72 is provided at the top of the air-fuel ratio sensor 70. The detection part 72 is located inside the connecting pipe 50 and exposed to the exhaust gas passing through it. The air-fuel ratio sensor 70 detects the air-fuel ratio of the exhaust gas as the exhaust gas state. The air-fuel ratio sensor 70 is electrically connected to a control device that controls the drive of the engine 100. The control device controls the engine 100 based on the detection value of the air-fuel ratio sensor 70.
[0019] Figure 2 This is a cross-sectional view of exhaust purification device 1. Figure 2 What is displayed is the same as Figure 1 A cross-section parallel to the paper surface. A sheet-like component 18 is disposed between the inner circumferential surface of the first housing 12 of the first catalytic converter 10 and the outer circumferential surface of the first catalyst carrier 14. The sheet-like component 18 ensures exhaust gas sealing and holds the first catalyst carrier 14. A sheet-like component 38 is disposed between the inner circumferential surface of the second housing 32 of the second catalytic converter 30 and the outer circumferential surface of the second catalyst carrier 34. The sheet-like component 38 ensures exhaust gas sealing and holds the second catalyst carrier 34.
[0020] The downstream end 122 of the first housing 12 of the first catalytic converter 10 protrudes slightly downstream than the downstream end face 142 of the first catalyst support 14. In other words, the downstream end 122 protrudes further into the connecting pipe 50 than the downstream end face 142. The upstream end 321 of the second housing 32 of the second catalytic converter 30 protrudes slightly upstream than the upstream end face 341 of the second catalyst support 34. In other words, the upstream end 321 protrudes further into the connecting pipe 50 than the upstream end face 341.
[0021] The downstream end face 142 of the first catalyst carrier 14 is not parallel to the upstream end face 341 of the second catalyst carrier 34. The angle θ between the downstream end face 142 and the upstream end face 341 is set to an angle between 60 degrees and 120 degrees. Therefore, the central axis A of the connecting pipe 50 is not straight, but curved.
[0022] A predetermined gap C is provided between the downstream end 122 and the upstream end face 341 in the vertical direction D1, which is perpendicular to the downstream end face 142. In other words, the downstream end 122 does not overlap with the upstream end face 341 in the direction parallel to the downstream end face 142. As a result, exhaust gas passing through the first catalyst carrier 14 and exiting from the downstream end 122 flows uniformly into the upstream end face 341. If, for example, such a gap C is not provided, the downstream end 122 overlaps with the upstream end face 341 in the direction parallel to the downstream end face 142, then exhaust gas may not flow in sufficiently in the area of the upstream end face 341 where it overlaps with the downstream end 122. In this embodiment, because the gap C is provided as described above, exhaust gas flows uniformly into the upstream end face 341. As a result, the exhaust gas purification performance of the second catalyst carrier 34 is fully utilized, and the deterioration of exhaust emissions is suppressed.
[0023] The connecting pipe 50 includes an upstream section 52, a downstream section 54, and a throttling section 56. The upstream section 52 is connected to the first catalytic converter 10. The downstream section 54 is connected to the second catalytic converter 30. The throttling section 56 is located between the upstream section 52 and the downstream section 54. Specifically, the throttling section 56 is located approximately at the center of the length of the central axis A from the upstream section 52 to the downstream section 54. The cross-sectional area S6 perpendicular to the central axis A at the throttling section 56 is smaller than the cross-sectional areas S2 and S4 perpendicular to the central axis A in the upstream section 52 and the downstream section 54, respectively.
[0024] like Figure 2 As shown, a portion of the downstream end 122 of the first housing 12 of the first catalytic converter 10 is located in the throttling section 56. Therefore, exhaust gas passing through the downstream end 122 passes through a portion of the throttling section 56. Consequently, the cross-sectional area S61 through which the exhaust gas passes in the cross-sectional area S6 of the throttling section 56 is smaller than the cross-sectional area S6. Therefore, the flow velocity of the exhaust gas passing through the cross-sectional area S61 is faster than the flow velocity of the exhaust gas passing through the upstream section 52 and the downstream section 54, respectively. Thus, the flow velocity of the exhaust gas passing through the throttling section 56 is maintained above a certain value.
[0025] The detection section 72 of the air-fuel ratio sensor 70 faces the downstream end face 142 in the vertical direction D1 and is located within the cross-sectional area S61 where the flow rate is high, as described above. As a result, the deviation of the detection value of the air-fuel ratio sensor 72 caused by the variation in the flow rate of the exhaust gas passing around the detection section 72 is suppressed, and the detection accuracy of the air-fuel ratio sensor 72 is improved.
[0026] like Figure 2As shown, a portion of the downstream side of the first catalytic converter 10 is inserted into the upstream section 52. This prevents the first catalyst support 14 from dropping below its activation temperature due to external gases. Consequently, the exhaust gas purification performance of the first catalyst support 14 is fully utilized, and the deterioration of exhaust emissions is suppressed.
[0027] The downstream end 122 overlaps with the upstream end 321 of the second housing 32 in a direction parallel to the downstream end face 142, i.e., parallel direction D2. In this way, the first catalytic converter 10 and the second catalytic converter 30 are arranged close to each other, and the exhaust purification device 1 is miniaturized. Therefore, even if, as described above, it is located in the engine compartment of a vehicle, the arrangement of the exhaust purification device 1 becomes easy.
[0028] Furthermore, the connecting pipe 50 has a curved inner arc portion 51r. Since the downstream side of the first catalytic converter 10 is inserted into the arc portion 51r, the arc portion 51r can be formed to be relatively large. As a result, it becomes easier to form the connecting pipe 50 by stamping.
[0029] In the above embodiments, an air-fuel ratio sensor 70 was described as an example of a gas sensor, but the gas sensor is not limited to this. For example, the gas sensor may also be a sensor that detects the concentration of oxygen, carbon dioxide, NOx, or PM in exhaust gas. In addition, the gas sensor may also be a sensor that detects the temperature, flow rate, or pressure of exhaust gas.
[0030] The embodiments of the present invention have been described in detail above, but the present invention is not limited to these specific embodiments. Various modifications or alterations can be made within the scope of the spirit of the present invention as defined in the claims.
Claims
1. An exhaust purification device for an engine, comprising: A first catalytic converter includes a first housing and a first catalyst support held within the first housing; A second catalytic converter, located downstream of the first catalytic converter, includes a second housing and a second catalyst support held within the second housing; and A connecting pipe, which connects the first housing and the second housing, and whose central axis is bent; The first catalyst support has a downstream end face. The first housing has a downstream end that protrudes downstream from the downstream end face. The second catalyst support has an upstream end face. A gap is provided between the downstream end and the upstream end in a direction perpendicular to the downstream end face.
2. The exhaust purification device for an engine as described in claim 1, wherein, It has a gas sensor installed on the connecting pipe to detect the state of the exhaust gas. The connecting pipe has an upstream section, a downstream section, and a throttling section located between the upstream section and the downstream section. The cross-sectional area perpendicular to the central axis at the throttling section is smaller than the cross-sectional areas perpendicular to the central axis in both the upstream and downstream sections. The detection section of the gas sensor is located in the throttling section.
3. The exhaust purification device for an engine as described in claim 2, wherein, A portion of the downstream end is located in the throttling section. The detection section of the gas sensor faces the downstream end face in a direction perpendicular to the downstream end face.
4. The exhaust purification device for an engine as described in claim 3, wherein, A portion of the first catalyst support is located inside the connecting tube.
5. The exhaust purification device for the engine as described in any one of claims 1 to 4, The downstream end overlaps with the second housing in a direction parallel to the downstream end face.