A V-type double-cylinder exhaust manifold structure of a motorcycle

Abstract

The application discloses a V-shaped double-cylinder exhaust manifold structure of a motorcycle, which comprises an outlet pipe, a scald-preventing cover assembly, and an exhaust manifold h-shaped assembly in communication with the scald-preventing cover assembly, wherein the exhaust manifold h-shaped assembly is configured as follows: a first inlet pipe is arranged for introducing first-cylinder exhaust gas in a first direction; a second inlet pipe is arranged for introducing second-cylinder exhaust gas in a second direction; a special-shaped pipe is arranged for connecting the first inlet pipe and the second inlet pipe; and a baffle plate is arranged at the intersection of the first inlet pipe and the special-shaped pipe, and the baffle plate is provided with a through hole; wherein the special-shaped pipe is curved to change the flow direction of the second-cylinder exhaust gas, so that the first-cylinder exhaust gas and the second-cylinder exhaust gas can converge at the baffle plate in a manner that the flow directions of the first-cylinder exhaust gas and the second-cylinder exhaust gas have a set included angle. In the application, the intersection of the two exhaust pipes forms a channel similar to the letter "h", and such a structure enables the exhaust gas from the two cylinders to be better mixed and distributed at the intersection.

Description

Technical Field

[0001] This invention relates to the field of exhaust manifold technology, and more particularly to a V-type twin-cylinder exhaust manifold structure for motorcycles. Background Technology

[0002] The exhaust manifold of a motor vehicle is the component that connects the exhaust gas from the internal combustion engine to the muffler. For dual-cylinder or multi-cylinder internal combustion engines, each cylinder has its own exhaust pipe. Due to the spatial arrangement of the pipes, they are combined into a single exhaust pipe, which is then silenced by the muffler before being released into the atmosphere. To meet environmental protection requirements and reduce the emission of pollutants from motor vehicle exhaust, the current measure for motorcycles in China to meet the National IV emission standard is to install a three-way catalytic converter (commonly known as a catalyst) on the exhaust manifold. The three-way catalytic converter is either welded in series to the exhaust manifold or installed inside the muffler. The base structure of the three-way catalytic converter is a honeycomb pipe design, meaning that the walls of the honeycomb pipes are coated with precious metals such as platinum (Pt), rhodium (Rh), and palladium (Pd) as catalytic reaction media. Platinum, rhodium, and palladium, three precious metals with a fixed honeycomb structure, purify exhaust gases, converting them into harmless gases for discharge. During engine operation, acceleration, or driving, the air-fuel mixture burns in the engine cylinders and flows into the three-way catalytic converter for filtration. Because the exhaust manifold with this honeycomb structure creates significant airflow resistance, the surface temperature of this section of the exhaust pipe becomes extremely high. Simultaneously, the optimal operating temperature of the three-way catalytic converter is 375℃~800℃, allowing the three precious metals to reach their ignition temperature. Especially in motorcycles, the exhaust manifold connected to the muffler has a small gap between it and adjacent parts such as the rear tire and plastic components. Due to heat radiation, the surface temperature of the exhaust manifold and muffler cylinder becomes very high. Areas close to these parts are more susceptible to burns. Therefore, it is necessary to install heat-insulating materials or add an outer heat shield to the exhaust manifold surface to effectively reduce its temperature and prevent accidental damage to adjacent parts or burns to the rider.

[0003] In existing technology, typically, two exhaust pipes are installed at the exhaust port of a vehicle's two-cylinder engine to facilitate the layout and installation of the exhaust system. These two exhaust pipes are connected by a three-way exhaust manifold (either Y-shaped or T-shaped), and their intersection forms a single exhaust outlet, which is then output to the terminal exhaust muffler via a single exhaust pipe, saving space. To reduce heat radiation and heat transfer, high-temperature components such as the three-way catalytic converter welded to the exhaust manifold are covered with a layer of fiberglass to reduce heat transfer. Alternatively, metal heat shields or heat shields made of non-metallic materials (such as nylon) are used for insulation.

[0004] Existing technologies have the following drawbacks: T-type exhaust manifolds installed on motorcycles typically simply combine two exhaust pipes, which is inferior to "lowercase h" type exhaust pipes in terms of airflow distribution and handling of exhaust interference. Y-type connections are prone to problems such as localized airflow concentration and poor exhaust flow at the merging point, affecting exhaust efficiency. In contrast, the "lowercase h" type exhaust pipe, through its unique structural design, better solves these problems compared to traditional simple connection methods, resulting in more even intake airflow distribution, smoother exhaust, and improved engine performance. The relatively simple structure of the Y-type connection at the joint makes it susceptible to vibration and stress, leading to loosening and deformation. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a V-type twin-cylinder exhaust manifold structure for motorcycles.

[0006] The objective of this invention is achieved through the following technical solution: a V-shaped dual-cylinder exhaust manifold structure for a motorcycle, comprising an outlet pipe and a heat shield assembly, and further comprising an exhaust manifold h-shaped assembly connected to the heat shield assembly. The exhaust manifold h-shaped assembly is configured as follows: having a first inlet pipe for introducing exhaust gas from a first cylinder in a first direction; having a second inlet pipe for introducing exhaust gas from a second cylinder in a second direction; having a shaped tube for connecting the first inlet pipe and the second inlet pipe; and having a baffle plate disposed at the intersection of the first inlet pipe and the shaped tube, wherein the baffle plate is provided with a through hole, wherein the shaped tube is bent to change the flow direction of the exhaust gas from the second cylinder, so that the exhaust gas from the first cylinder and the exhaust gas from the second cylinder can converge at the baffle plate in a manner that has a set angle between their respective flow directions.

[0007] Preferably, the irregular tube is formed by welding a first forming plate and a second forming plate, the first inlet pipe is connected to the anti-scalding cover assembly via a connecting pipe, and the shape of the projection of the exhaust manifold h-shaped assembly on the horizontal plane can be defined by an "h" shape.

[0008] Preferably, both the first inlet pipe and the second inlet pipe are provided with U-grooves and stepped openings at their ends, the first inlet pipe is provided with a first irregularly shaped opening, the second inlet pipe is provided with a second irregularly shaped opening, and the connecting pipe is provided with a third irregularly shaped opening.

[0009] Preferably, the first inlet pipe is provided with a concave surface and three convex surfaces.

[0010] Preferably, the anti-scalding cover assembly includes a three-way catalytic converter, a first tile-shaped anti-scalding cover, and a second tile-shaped anti-scalding cover. The first tile-shaped anti-scalding cover and the second tile-shaped anti-scalding cover are welded together to form a tubular space. The three-way catalytic converter is disposed within the tubular space. Fiberglass is disposed between the three-way catalytic converter and the first tile-shaped anti-scalding cover, and also between the three-way catalytic converter and the second tile-shaped anti-scalding cover.

[0011] Preferably, one end of the tubular space is connected to the connecting pipe, and the other end of the tubular space is connected to the outlet pipe. A first conical pipe is provided between the connecting pipe and the three-way catalytic converter, and a second conical pipe is provided between the outlet pipe and the three-way catalytic converter.

[0012] Preferably, the connection between the connecting pipe and the anti-scalding cover assembly is tightened and fixed by a first clamp, and the connection between the outlet pipe and the anti-scalding cover assembly is tightened and fixed by a second clamp.

[0013] Preferably, both the first and second tile-shaped heat shields are provided with stepped surface layers, such that the edge of the first tile-shaped heat shield can be embedded in the stepped surface layer of the second tile-shaped heat shield, or the edge of the second tile-shaped heat shield can be embedded in the stepped surface layer of the first tile-shaped heat shield.

[0014] Preferably, when viewed in the front view of the V-shaped twin-cylinder exhaust manifold structure, the first inlet pipe and the second inlet pipe are perpendicular to each other, and the second inlet pipe is parallel to the anti-scalding cover assembly.

[0015] The present invention has the following advantages: 1. Lowercase "h" type exhaust manifold: In the "h" type dual intake single exhaust manifold structure, the intersection of the two exhaust pipes forms a channel resembling the letter "h". This structure allows the exhaust gases from the two cylinders to be better mixed and distributed at the intersection. When the exhaust gases enter the subsequent exhaust system, the airflow distribution is more uniform, reducing the possibility of excessively concentrated or turbulent local airflow.

[0016] 2. The exhaust manifold is designed with baffles and small round holes in the middle of the baffles. These small holes can change the airflow state inside the exhaust pipe, causing damping and scattering effects as the airflow passes through them, thereby reducing the speed and energy of the airflow and decreasing noise. In addition, the small holes can also make the airflow distribution inside the exhaust pipe more uniform, reducing local airflow impact and resonance, further reducing noise levels.

[0017] 3. The two-part tile-shaped heat shield covering the middle fiberglass layer reduces heat transfer to the surrounding parts of the vehicle body, resulting in better heat insulation. Attached Figure Description

[0018] Figure 1 This is a three-dimensional structural diagram of the V-type twin-cylinder exhaust manifold structure of the present invention; Figure 2 This is a front view of the V-type twin-cylinder exhaust manifold structure of the present invention; Figure 3 This is a top view of the V-type twin-cylinder exhaust manifold structure of the present invention; Figure 4 This is a side view of the V-type twin-cylinder exhaust manifold structure of the present invention; Figure 5 This is a sectional view of section CC; Figure 6 This is a sectional view of section GG; Figure 7 This is a sectional view of section KK; Figure 8 This is a schematic diagram showing the airflow direction of the exhaust manifold. In the diagram, 100-exhaust manifold H-type assembly, 110-first inlet pipe, 140-baffle plate, 150-second inlet pipe, 160-connecting pipe, 220-first forming plate, 230-second forming plate, 200-irregular-shaped pipe, 111-U-groove, 112-stepped pipe opening, 141-through hole, 201-first irregular-shaped pipe opening, 202-second irregular-shaped pipe opening, 203-third irregular-shaped pipe opening, 221-convex surface, 223-concave surface, 300-outlet pipe, 500-anti-scalding cover assembly, 510-first tile-shaped anti-scalding cover, 520-second tile-shaped anti-scalding cover, 530-first clamp, 540-first conical pipe, 550-three-way catalytic converter, 560-glass fiber, 570-second conical pipe, 580-second clamp, 511-stepped surface layer, 512-edge. Detailed Implementation

[0019] The present invention will be further described below with reference to the accompanying drawings. The scope of protection of the present invention is not limited to the following description: like Figures 1 to 7As shown, the present invention provides a V-shaped twin-cylinder exhaust manifold structure for a motorcycle, including an outlet pipe 300 and a heat shield assembly 500, and an exhaust manifold h-shaped assembly 100 connected to the heat shield assembly 500. The exhaust manifold h-shaped assembly 100 is configured as follows: having a first inlet pipe 110 for introducing exhaust gas from the first cylinder in a first direction; having a second inlet pipe 150 for introducing exhaust gas from the second cylinder in a second direction; having a shaped pipe 200 for connecting the first inlet pipe 110 and the second inlet pipe 150; and having a baffle plate 140 disposed at the intersection of the first inlet pipe 110 and the shaped pipe 200. The baffle plate 140 is provided with a through hole 141. The shaped pipe 200 is curved to change the flow direction of the exhaust gas from the second cylinder, so that the exhaust gas from the first cylinder and the exhaust gas from the second cylinder can converge at the baffle plate 140 in a manner that has a set angle between their respective flow directions. The irregular tube 200 is formed by welding the first forming plate 220 and the second forming plate 230. The first inlet pipe 110 is connected to the anti-scalding cover assembly 500 via the connecting pipe 160. The shape of the projection of the exhaust manifold h-shaped assembly 100 on the horizontal plane can be defined by the "h" shape. The first inlet pipe 110 is provided with a concave surface 223 and three convex surfaces 221. The outer surface is fixed with the concave surface 223 and three reinforcing rib convex surfaces 221. The intersecting surfaces can increase the strength and resist the impact of airflow. In the main view of the V-type dual-cylinder exhaust manifold structure, the first inlet pipe 110 and the second inlet pipe 150 are perpendicular to each other, and the second inlet pipe 150 is parallel to the anti-scalding cover assembly 500. Through the above arrangement, at least the following technical effects can be achieved: (1) In the "lowercase letter h" type dual-intake single-exhaust manifold structure, the intersection of the two exhaust pipes forms a channel similar to the letter "h". This structure allows the exhaust gas from the two cylinders to be better mixed and distributed at the intersection. When exhaust gases enter the subsequent exhaust system, the airflow distribution is more uniform, reducing localized over-concentration or turbulence. This helps improve exhaust efficiency, allowing the engine to expel exhaust gases more smoothly during the exhaust process, reducing exhaust back pressure, and thus improving engine performance, such as increasing power output and improving fuel economy. Specifically: 1. Reduced exhaust interference: The two cylinders of a V-twin engine produce exhaust pulses of different phases when they operate. The "lowercase h" shaped exhaust pipe design can alleviate this interference between exhaust pulses to some extent. When exhaust gases from both cylinders enter the exhaust pipe simultaneously, the "h" shaped structure provides a more reasonable flow path for the exhaust gases, reducing mutual impact and interference between exhaust airflows from different cylinders, making the exhaust process smoother, further optimizing engine operation, and reducing vibration and noise. 2. Enhanced structural stability: From a structural perspective, the "lowercase h" shaped connection method can increase the overall strength and stability of the exhaust pipe system.Compared to a simple Y-type connection, this added structure creates a more complex support and connection at the joint, better able to withstand the vibrations and stresses generated during engine operation. For motorcycles, which are frequently in dynamic driving conditions, the structural stability of the exhaust system is crucial, reducing problems such as exhaust pipe damage and loosening caused by vibration and stress, and extending the exhaust pipe's service life. 3. Facilitates exhaust system layout and installation: Space layout is a key factor in motorcycle design. The "lowercase h" type exhaust pipe design can better adapt to the motorcycle's body structure and space constraints, providing greater flexibility in exhaust system layout. For example, in some V-twin engine motorcycles, due to the engine's structural characteristics and space limitations, using an "h" type exhaust pipe makes it easier to connect the exhaust pipe to the engine and rationally arrange the exhaust system's direction within a limited space, making the entire motorcycle structure more compact and aesthetically pleasing. 4. More robust and reliable structure: From the perspective of structural strength and reliability, the more complex connection method of the "lowercase h" type exhaust pipe provides better support and fixation. In the long-term use, the "lowercase h" type exhaust pipe is more robust and reliable, and can better ensure the normal operation of the exhaust system. (2) Adding a baffle at the junction, and opening a small round hole in the middle of the baffle to allow a small amount of airflow to pass through, can have the following advantages: 1. Balance air pressure: During the motorcycle's operation, the airflow speed and pressure in the exhaust pipe will change continuously. The small round hole in the middle of the baffle can play a role in balancing the air pressure in the exhaust pipe. When exhaust gas is discharged from the engine and enters the exhaust pipe, the airflow will form a certain pressure fluctuation in the exhaust pipe. The small round hole can allow some airflow to pass through, thereby alleviating the pressure change in the exhaust pipe to a certain extent and keeping the air pressure relatively stable. This helps to improve the working stability of the exhaust system and reduce the adverse effects on engine performance caused by excessive air pressure fluctuations. 2. Promote exhaust gas discharge: The small hole of the baffle allows a small amount of airflow to pass through, which can form a certain airflow circulation in the exhaust pipe. This airflow circulation can help push the exhaust gas to be discharged from the exhaust pipe faster, avoid the accumulation of exhaust gas in the exhaust pipe, and improve exhaust efficiency. Especially when the engine is running at low speeds or idling, the exhaust gas is discharged relatively slowly. At this time, the small holes are more effective in promoting exhaust gas discharge, reducing the amount of residual exhaust gas in the exhaust pipe, and minimizing its adverse effects on the engine. They also help the exhaust gas from cylinder 1 smoothly enter the exhaust stack for discharge. 3. Noise Reduction: Airflow in the exhaust pipe generates noise, especially when the airflow is fast or unstable. The small round holes in the baffle alter the airflow state within the exhaust pipe, creating damping and scattering effects as the airflow passes through, thereby reducing the airflow speed and energy and decreasing noise generation.In addition, the small holes can make the airflow distribution in the exhaust pipe more uniform, reduce local airflow impact and resonance, and further reduce the noise level.

[0020] Preferably, both the first inlet pipe 110 and the second inlet pipe 150 are provided with U-slots 111 and stepped openings 112 at their ends. The first inlet pipe 110 is provided with a first irregularly shaped opening 201, the second inlet pipe 150 is provided with a second irregularly shaped opening 202, and the connecting pipe 160 is provided with a third irregularly shaped opening 203. The four U-slots 111 serve as a seal when the pipe openings are contracted, and the stepped openings 112 serve as a positioning feature when connecting and fixing the engine exhaust pipe.

[0021] Preferably, the anti-scalding cover assembly 500 includes a three-way catalytic converter 550, a first tile-shaped anti-scalding cover 510, and a second tile-shaped anti-scalding cover 520. The first tile-shaped anti-scalding cover 510 and the second tile-shaped anti-scalding cover 520 are welded together to form a tubular space. The three-way catalytic converter 550 is disposed within the tubular space. Glass fiber 560 is disposed between the three-way catalytic converter 550 and the first tile-shaped anti-scalding cover 510, and between the three-way catalytic converter 550 and the second tile-shaped anti-scalding cover 520. One end of the tubular space is connected to a connecting pipe 160, and the other end of the tubular space is connected to an outlet pipe 300. A first conical pipe 540 is disposed between the connecting pipe 160 and the three-way catalytic converter 550, and a second conical pipe 570 is disposed between the outlet pipe 300 and the three-way catalytic converter 550. The connection between the connecting pipe 160 and the anti-scalding cover assembly 500 is tightened and fixed by the first clamp 530, and the connection between the outlet pipe 300 and the anti-scalding cover assembly 500 is tightened and fixed by the second clamp 580. Both the first tile-shaped anti-scalding cover 510 and the second tile-shaped anti-scalding cover 520 are provided with stepped surface layers 511, allowing the edge 512 of the first tile-shaped anti-scalding cover 510 to be embedded in the stepped surface layer 511 of the second tile-shaped anti-scalding cover 520, or vice versa. The outer surface of the three-way catalytic converter is wrapped with fiberglass and then fixed with two half-tile-shaped metal anti-scalding covers. The anti-scalding covers have tapered designs at both ends, and are fixed together with clamps to increase strength and prevent deformation. The tile-shaped metal anti-scalding covers are made of 304 stainless steel sheet by stamping. This invention improves the structure of the heat shield to provide multi-layer heat insulation, which reduces heat transfer to surrounding parts of the vehicle body and provides better heat insulation.

[0022] like Figure 8As shown, the exhaust gas flow from the first cylinder enters through the first inlet pipe 110 and flows towards the first shaped pipe opening 201. The exhaust gas flow from the second cylinder enters through the second inlet pipe 150 and flows towards the second shaped pipe opening 202. After passing through a semi-circular air passage, the gas reaches the third shaped pipe opening 203. The exhaust gas flows from the first cylinder and the exhaust gas flows from the second cylinder into the connecting pipe 160 at the third shaped pipe opening 203, then pass through the first conical pipe 540, the three-way catalytic converter 550, and the second conical pipe 570, finally exiting from the outlet pipe 300. The baffle 140 serves both as a guide for the exhaust gas flow from the first cylinder to the second cylinder, preventing reverse airflow from returning to the engine exhaust port, and as a means to make the airflow distribution in the exhaust pipe more uniform, reducing local airflow impact and resonance, and further reducing noise levels. The through hole 141 in the middle of the baffle plate can change the airflow state in the exhaust pipe, so that the airflow generates a certain damping and scattering effect when passing through the small hole, thereby reducing the speed and energy of the airflow and reducing the generation of noise.

[0023] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A V-type twin-cylinder exhaust manifold structure for a motorcycle, comprising an outlet pipe (300) and a heat shield assembly (500), characterized in that, It also includes an exhaust manifold h-type assembly (100) connected to the heat shield assembly (500), the exhaust manifold h-type assembly (100) being configured as follows: It has a first inlet pipe (110) for introducing exhaust gas from the first cylinder in a first direction; It has a second inlet pipe (150) for introducing exhaust gas from the second cylinder in a second direction; It has a shaped tube (200) for connecting the first inlet tube (110) and the second inlet tube (150). A baffle plate (140) is provided at the intersection of the first inlet pipe (110) and the shaped pipe (200). The baffle plate (140) is provided with a through hole (141). The shaped pipe (200) is bent to change the flow direction of the exhaust gas from the second cylinder, so that the exhaust gas from the first cylinder and the exhaust gas from the second cylinder can converge at the baffle plate (140) in such a way that they have a set angle between their flow directions.

2. The V-type twin-cylinder exhaust manifold structure according to claim 1, characterized in that, The irregular tube (200) is formed by welding a first forming plate (220) and a second forming plate (230). The first inlet pipe (110) is connected to the anti-scalding cover assembly (500) via a connecting pipe (160). The shape of the projection of the exhaust manifold h-shaped assembly (100) on the horizontal plane can be defined by an "h" shape.

3. The V-type twin-cylinder exhaust manifold structure according to claim 2, characterized in that, The ends of the first inlet pipe (110) and the second inlet pipe (150) are provided with U-grooves (111) and stepped pipe openings (112). The first inlet pipe (110) is provided with a first irregular pipe opening (201), the second inlet pipe (150) is provided with a second irregular pipe opening (202), and the connecting pipe (160) is provided with a third irregular pipe opening (203).

4. The V-type twin-cylinder exhaust manifold structure according to claim 2, characterized in that, The first inlet pipe (110) is provided with a concave surface (223) and three convex surfaces (221).

5. The V-type twin-cylinder exhaust manifold structure according to claim 2, characterized in that, The heat shield assembly (500) includes a three-way catalytic converter (550), a first tile-shaped heat shield (510), and a second tile-shaped heat shield (520). The first tile-shaped heat shield (510) and the second tile-shaped heat shield (520) are welded together to form a tubular space. The three-way catalytic converter (550) is disposed in the tubular space. Glass fiber (560) is disposed between the three-way catalytic converter (550) and the first tile-shaped heat shield (510), and between the three-way catalytic converter (550) and the second tile-shaped heat shield (520).

6. The V-type twin-cylinder exhaust manifold structure according to claim 5, characterized in that, One end of the tubular space is connected to the connecting pipe (160), and the other end of the tubular space is connected to the outlet pipe (300). A first conical pipe (540) is provided between the connecting pipe (160) and the three-way catalytic converter (550), and a second conical pipe (570) is provided between the outlet pipe (300) and the three-way catalytic converter (550).

7. The V-type twin-cylinder exhaust manifold structure according to claim 5, characterized in that, The connection between the connecting pipe (160) and the anti-scalding cover assembly (500) is tightened and fixed by the first clamp (530), and the connection between the outlet pipe (300) and the anti-scalding cover assembly (500) is tightened and fixed by the second clamp (580).

8. The V-type twin-cylinder exhaust manifold structure according to claim 5, characterized in that, Both the first tile-shaped heat shield (510) and the second tile-shaped heat shield (520) are provided with stepped surface layers (511), so that the edge (512) of the first tile-shaped heat shield (510) can be embedded in the stepped surface layer (511) of the second tile-shaped heat shield (520), or the edge (512) of the second tile-shaped heat shield (520) can be embedded in the stepped surface layer (511) of the first tile-shaped heat shield (510).

9. The V-type twin-cylinder exhaust manifold structure according to claim 2, characterized in that, In the front view of the V-shaped twin-cylinder exhaust manifold structure, the first inlet pipe (110) and the second inlet pipe (150) are perpendicular to each other, and the second inlet pipe (150) is parallel to the anti-scalding cover assembly (500).

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