exhaust pipe

Abstract

The utility model provides a kind of exhaust pipe.The exhaust pipe is used to make the exhaust from the engine of car flow, adopt the double-layer pipe structure of inner tube insertion in the inner diameter side of outer tube, sleeve is provided in the upstream side of exhaust flow direction in the inner tube, the sleeve is configured as the shape of gradually reducing diameter from the upstream side of exhaust flow direction to downstream side.Based on the structure, in the case of installing sensor in double-layer pipe structure part, without reducing the pipe diameter of double-layer pipe structure part, exhaust can be more easily contacted to sensor, and back pressure will not be caused to rise.

Description

Technical Field

[0001] This utility model relates to an exhaust pipe for automobiles. Background Technology

[0002] In existing automotive exhaust pipes, such as those with sensors (e.g., oxygen sensors or air-fuel ratio sensors) located before the catalytic converter, a double-layer pipe structure is used to minimize heat loss from the inner pipe to the outer pipe. This not only improves the thermal insulation of the exhaust pipe but also enhances the purification performance of the catalytic converter.

[0003] Typically, in exhaust pipes with this double-pipe structure, the sensor is sometimes installed in the area where the outer pipe and the inner pipe overlap (i.e., the double-pipe structure portion). The sensor is installed so that it extends from the outer diameter side of the outer pipe to the inner diameter side of the inner pipe.

[0004] In this situation, it is necessary to make it as easy as possible for the exhaust gas to contact the sensor probe exposed in the inner tube. To this end, reducing the diameter of the double-walled tube structure would make it easier for the exhaust gas to contact the sensor probe; however, reducing the diameter would also lead to an increase in the back pressure of the exhaust gas. Utility Model Content

[0005] In view of the above situation, the purpose of this utility model is to provide an exhaust pipe that allows the exhaust to easily contact the sensor without reducing the diameter of the double-layer pipe structure when the sensor is installed in the double-layer pipe structure.

[0006] As a technical solution to solve the above-mentioned technical problems, the present invention provides an exhaust pipe for allowing exhaust gas discharged from the engine of a car to flow. The exhaust pipe adopts a double-layer pipe structure in which the inner pipe is inserted into the inner diameter side of the outer pipe. The feature is that a sleeve is provided on the upstream side of the exhaust flow direction in the inner pipe, and the sleeve is configured to gradually narrow from the upstream side to the downstream side of the exhaust flow direction.

[0007] In addition, in the exhaust pipe of the present invention, it is preferable that a sensor is provided in the area where the outer pipe and the inner pipe overlap, and the sensor is installed to penetrate from the outer diameter side of the outer pipe to the inner diameter side of the inner pipe.

[0008] In addition, in the exhaust pipe of the present invention, it is preferable that a catalytic converter is provided on the downstream side of the exhaust flow direction in the outer pipe.

[0009] The advantages of the exhaust pipe of this invention with the above-described structure are that, by employing a double-layer pipe structure, the thermal insulation performance of the exhaust pipe is improved, which helps to enhance the purification capacity of the catalytic converter when it is located downstream of the double-layer pipe structure. Furthermore, since a sleeve is provided upstream of the exhaust flow direction in the inner pipe, the exhaust flow velocity increases and the pressure decreases when the exhaust flows through the sleeve due to the Venturi effect. Therefore, without reducing the diameter of the double-layer pipe structure section, the exhaust flowing through the sleeve can also enter the double-layer pipe structure section with a relatively strong force. Thus, when a sensor is installed in the double-layer pipe structure section, the exhaust can easily contact the sensor. Moreover, since there is no need to reduce the diameter of the double-layer pipe structure section, it will not lead to an increase in back pressure. Attached Figure Description

[0010] Figure 1 is a perspective view showing the outline structure of the exhaust pipe according to an embodiment of the present invention. Detailed Implementation

[0011] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. FIG1 is a perspective view showing the general structure of the exhaust pipe 1 according to this embodiment.

[0012] The exhaust pipe 1 is used to allow exhaust gas from the engine of the car to flow. As shown in Figure 1, the exhaust pipe 1 adopts a double-layer pipe structure in which the inner pipe 3 is inserted into the inner diameter side of the outer pipe 2.

[0013] A catalyst 5 is installed on the downstream side of the exhaust flow direction in the outer pipe 2. A sliding mesh 6 is installed on the upstream side of the catalyst 5 in the outer pipe 2. The sliding mesh 6 is used to fix the inner pipe 3, and is set to a sliding state in order to absorb the thermal expansion difference between the outer pipe 2 and the inner pipe 3.

[0014] A sleeve 4 is provided on the upstream side of the exhaust flow direction in the inner tube 3, that is, the sleeve 4 is inserted into the inner diameter side of the inner tube 3. The sleeve 4 is configured to gradually narrow from the upstream side to the downstream side in the exhaust flow direction. That is, the closer to the downstream side in the exhaust flow direction, the smaller the inner diameter of the sleeve 4.

[0015] Additionally, although not shown in the diagram, a catalytic converter may sometimes be installed upstream of the exhaust inlet (not marked) of the inner pipe 3. Furthermore, the outer pipe 2, inner pipe 3, and sleeve 4 may be made of metal materials (such as stainless steel).

[0016] Additionally, a sensor 7 is installed in the area where the outer pipe 2 and the inner pipe 3 overlap (the double-layer pipe structure section). This sensor 7 is, for example, an oxygen sensor or an air-fuel ratio sensor. As shown in Figure 1, the sensor 7 is installed so that it extends from the outer diameter side of the outer pipe 2 into the inner diameter side of the inner pipe 3, with the probe of the sensor 7 located inside the inner pipe 3. The sensor 7 detects the exhaust gas by bringing its probe, exposed inside the inner pipe 3, into contact with the exhaust gas flowing inside the inner pipe 3.

[0017] Next, the function and effect of exhaust pipe 1 will be explained.

[0018] As exhaust flows through sleeve 4, the inner diameter of sleeve 4 decreases towards the downstream side of the exhaust flow direction. Therefore, due to the Venturi effect of sleeve 4, the exhaust velocity increases and the pressure decreases. Consequently, without reducing the diameter of the aforementioned double-walled pipe structure, the exhaust flowing through sleeve 4 can still pass through the double-walled pipe structure with considerable force. Thus, the probe of sensor 7, located inside the inner tube 3, installed in the double-walled pipe structure, can easily contact the exhaust.

[0019] At the same time, since there is no need to reduce the diameter of the aforementioned double-layer pipe structure, the back pressure will not increase.

[0020] In addition, since the exhaust pipe 1 adopts a double-layer pipe structure to improve the heat insulation performance of the exhaust pipe, the purification performance of the catalytic converter 5 located on the downstream side of the double-layer pipe structure can be improved.

[0021] However, this utility model is not limited to the above-described embodiments and can be applied and modified in various ways. For example, in the above-described embodiment, the axial and radial dimensions of the sleeve 4 can be appropriately set according to the actual situation. In addition, the axial dimension of the area where the outer tube 2 and the inner tube 3 overlap (the double-layer tube structure portion) can also be appropriately set according to the actual situation.

Claims

1. An exhaust pipe for facilitating the flow of exhaust gas from a vehicle engine, comprising a double-layer pipe structure with an inner pipe inserted into the inner diameter side of an outer pipe, characterized in that: A sleeve is provided on the upstream side of the exhaust flow direction in the inner tube, and the sleeve is configured to gradually narrow from the upstream side to the downstream side of the exhaust flow direction.

2. The exhaust pipe as described in claim 1, characterized in that: A sensor is provided in the area where the outer tube and the inner tube overlap, and the sensor is installed to extend from the outer diameter side of the outer tube to the inner diameter side of the inner tube.

3. The exhaust pipe as described in claim 1 or 2, characterized in that: A catalytic converter is provided on the downstream side of the exhaust flow direction in the outer pipe.

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