Exhaust bypass structure for a high-power marine engine

Abstract

This utility model discloses an exhaust gas bypass structure for a high-power marine engine, including an exhaust pulse pipe and a main exhaust pipe connecting the turbocharger; the exhaust pulse pipe is bypassed to an exhaust gas bypass exhaust pipe assembly, which is connected to an exhaust gas bypass valve controlled by a control air circuit. The exhaust gas bypass valve is connected to the main exhaust pipe; the control air circuit includes a control intake pipe connected to the control intake port of the exhaust gas bypass valve and a control exhaust pipe connected to the control exhaust port of the exhaust gas bypass valve. An electric pressure regulating valve is installed in the control intake pipe, and an electromagnetic relief valve is installed in the control exhaust pipe; both the electric pressure regulating valve and the electromagnetic relief valve are connected to the engine's controller circuit. The controller of this utility model can control the opening and closing of the exhaust gas bypass valve by controlling the linkage of the electric pressure regulating valve and the electromagnetic relief valve, thereby adjusting the amount of high-temperature exhaust gas entering the turbocharger.

Description

Technical Field

[0001] This utility model relates to the technical field of marine engines, and in particular to an exhaust bypass structure for a high-power marine engine. Background Technology

[0002] Global warming and the exacerbation of extreme weather events are causing systemic impacts on the Earth's ecosystems. Greenhouse gases and pollutants emitted by ships are severely affecting the global climate and marine ecosystems. Currently, the International Maritime Organization (IMO) uses indices such as the CII (Carbon Intensity Index), EEXI (Existing Ship Energy Efficiency Index), and EEDI (Energy Efficiency Design Index for New Ships) to regulate ship operation and construction. EEXI and EEDI work by limiting engine power, optimizing fuel combustion efficiency, and forcing engines to reduce fuel consumption, thereby reducing carbon emissions.

[0003] Marine engines, as the primary prime movers of ships, are widely used in human society. The design and selection of marine engines generally involves matching the turbocharger to the engine's 80-90% partial load condition, while ensuring that the turbocharger speed does not exceed the limit when the engine is under 110% overload. This ensures that the ship can deliver maximum power for emergency avoidance. Due to the overload requirement, the turbocharger speed is relatively low under 80-90% load. The boost air pressure generated by the turbocharger under certain conditions is related to its speed; higher speed results in higher air pressure and a larger intake volume. With a suitable air-fuel ratio, fuel combustion is better, and fuel efficiency is improved. However, the load conditions during ship operation are typically even lower, ranging from 50% to 80%, resulting in even lower turbocharger speeds and lower air pressures, deviating from the optimal matching point for the diesel engine. Furthermore, the complexity of the marine environment means that conventional turbocharger matching cannot be well adapted to the ship's operational load conditions. In this regard, research and application of turbocharger matching and control in the field of high-power marine engines can effectively improve the economic efficiency of ship operation and reduce carbon emissions. Summary of the Invention

[0004] The technical problem to be solved by this utility model is to provide a simple, compact, safe and reliable exhaust bypass structure for a marine high-power engine, which is in response to the current situation of the prior art.

[0005] The technical solution adopted by this utility model to solve the above-mentioned technical problems is as follows: An exhaust gas bypass structure for a high-power marine engine includes an exhaust pulse pipe and an exhaust manifold connecting to a turbocharger; the exhaust pulse pipe is bypassed to an exhaust gas bypass exhaust pipe assembly, which is connected to an exhaust gas bypass valve controlled by a control air circuit, and the exhaust gas bypass valve is connected to the exhaust manifold; the control air circuit includes a control intake pipe connected to the control intake port of the exhaust gas bypass valve and a control exhaust pipe connected to the control exhaust port of the exhaust gas bypass valve, an electric pressure regulating valve is installed in the control intake pipe, and an electromagnetic relief valve is installed in the control exhaust pipe; both the electric pressure regulating valve and the electromagnetic relief valve are connected to the engine's controller circuit; the controller controls the opening and closing of the exhaust gas bypass valve by controlling the electric pressure regulating valve and the electromagnetic relief valve with electrical signals, thereby adjusting the amount of high-temperature exhaust gas entering the turbocharger.

[0006] To optimize the above technical solution, the specific measures also include: The aforementioned exhaust bypass pipe assembly is fixedly mounted on the engine's intercooler via an assembly bracket. The exhaust bypass pipe assembly consists of an exhaust bypass connecting pipe, a corrugated pipe, and an exhaust bypass bend connected in sequence. The exhaust bypass connecting pipe is a two-in-one connecting pipe that combines two branch pipes into one main pipe. The intake ends of both branch pipes are connected to the bypass outlet of the exhaust pulse pipe via flanges and flange gaskets.

[0007] The aforementioned waste gas bypass valve is assembled from a valve body, a valve cover plate, and a valve assembly. The valve body has a waste gas inlet for connecting with the waste gas bypass bend, a waste gas outlet for connecting with the exhaust main pipe, and a waste gas discharge channel for connecting the waste gas inlet and the waste gas outlet. The valve body also has a valve cavity formed therein, consisting of a piston chamber and a guide hole. The valve cavity is coaxially connected to the waste gas inlet. The valve assembly is located in the valve cavity and can control the opening or closing of the waste gas inlet. The valve cover plate is fitted to the valve cavity opening.

[0008] The aforementioned valve assembly consists of a bypass valve stem, a valve stem guide, a valve spring, and a piston. The valve stem guide is tightly fitted and positioned in the guide hole of the valve chamber. The bypass valve stem slides through the valve stem guide and extends into the exhaust gas inlet of the valve body. The bottom of the bypass valve stem is formed with a valve seat for sealing and engaging with the exhaust gas inlet. The piston is positioned and mounted on the upper end of the bypass valve stem via a locking nut. The valve spring is fitted onto the bypass valve stem and located in the piston chamber of the valve chamber. The upper end of the valve spring abuts against the bottom surface of the piston, and the lower end of the valve spring presses against the annular surface at the bottom of the piston chamber.

[0009] The piston chamber located between the piston and the valve cover plate constitutes the working gas chamber; the control air inlet and control air outlet are both located on the valve cover plate and are connected to the working gas chamber; the piston is fitted with piston rings to prevent the control gas from flowing downwards; the bottom of the piston chamber has a leakage air outlet connected to the atmosphere.

[0010] A valve seat ring is tightly fitted into the aforementioned exhaust gas inlet, and the valve seat at the bottom of the bypass valve stem is sealed to the valve seat ring. A first cooling water chamber for cooling the valve seat ring is provided between the outer circumferential surface of the valve seat ring and the inner wall of the exhaust gas inlet. A first cooling water inlet and a first cooling water outlet for providing circulating cooling water to the first cooling water chamber are provided at the lower end of the valve body.

[0011] A cooling water jacket is fitted and installed on the outer peripheral surface of the upper end of the valve body and in the moving area of ​​the piston; a second cooling water cavity is formed between the cooling water jacket and the outer wall of the valve body, and the cooling water jacket is provided with a second cooling water inlet and a second cooling water outlet for providing circulating cooling water to the second cooling water cavity.

[0012] A gap air chamber is provided between the bypass valve stem and the valve stem guide. Pressurized cooling air is introduced into the gap air chamber. The pressurized cooling air is used to prevent exhaust gas from entering the gap between the bypass valve stem and the valve stem guide when the bypass valve stem is working.

[0013] The valve body is provided with a pressurized cooling air inlet, and the valve stem guide is provided with a radial connecting hole for connecting the pressurized cooling air inlet and the gap air chamber; the bypass valve stem is formed with an exhaust channel for guiding the pressurized cooling air in the gap air chamber into the exhaust gas discharge channel of the valve body.

[0014] The control gas in the aforementioned intake control pipeline comes from a compressed air cylinder, which is connected to the intake port of the intake control pipeline; the exhaust port of the exhaust control pipeline is connected to the outside atmosphere; the cooling water in the first and second cooling water chambers comes from the engine's internal cooling water main pipe; and the boosted cooling air comes from the engine's intercooler rear intake pipe.

[0015] Compared with existing technologies, this utility model features an exhaust bypass valve between the exhaust bypass pipe assembly and the main exhaust pipe. This exhaust bypass valve can be opened or closed under the control of the control air circuit. An electric pressure regulating valve and a solenoid relief valve are installed in the control air circuit, and these valves are intelligently controlled by the engine controller (ECU). The ECU analyzes and processes the collected pressure and speed signals from the turbocharger and then transmits control electrical signals to control the electric pressure regulating valve and the solenoid relief valve in conjunction with the opening and closing of the exhaust bypass valve. This adjusts the amount of high-temperature exhaust gas entering the turbocharger from the engine exhaust pipe, preventing the turbocharger from overspeeding, controlling the pressure of the boosted air, and achieving a controllable and adjustable air-fuel ratio. This allows the engine performance to be optimized to the best point according to the needs of ship operation. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of this utility model; Figure 2This is a schematic diagram of the structure of the exhaust bypass pipe assembly of this utility model; Figure 3 This is a schematic diagram of the structure of the waste gas bypass valve of this utility model; Figure 4 yes Figure 3 A magnified view of a portion of point I; Figure 5 This is a schematic diagram of the valve housing of this utility model; Figure 6 This is a schematic diagram of the control and cooling principle of this utility model. Detailed Implementation

[0017] The embodiments of this utility model will be described in further detail below with reference to the accompanying drawings.

[0018] Figures 1 to 6 This is a schematic diagram of the structure of this utility model.

[0019] The attached figures are labeled as follows: gap air chamber J1, control intake pipe L1, control exhaust pipe L2, lock nut M, first cooling water chamber Q1, second cooling water chamber Q2, leakage air outlet X1, exhaust pulse pipe 1, exhaust bypass exhaust pipe assembly 2, exhaust bypass connection pipe 21, bellows 22, exhaust bypass bend 23, exhaust bypass valve 3, valve body 31, exhaust inlet 31a, exhaust outlet 31b, exhaust emission channel 31c, valve chamber 31d, working air chamber 31e, first cooling water inlet 31f. 1. First cooling water outlet 31g, booster cooling air inlet 31h, valve cover plate 32, control air inlet 32a, control exhaust port 32b, bypass valve stem 33, exhaust channel 33a, valve seat 331, valve stem guide 34, radial connecting hole 34a, valve spring 35, piston 36, piston ring 37, valve seat ring 38, cooling water jacket 39, second cooling water inlet 39a, second cooling water outlet 39b, exhaust manifold 4, electric pressure regulating valve 5, electromagnetic relief valve 6, controller 7, booster 8, intercooler 9.

[0020] like Figures 1 to 6As shown, this utility model discloses an exhaust gas bypass structure for a high-power marine engine. The exhaust gas bypass structure includes an exhaust pulse pipe 1 connected to a turbocharger 8 and an exhaust manifold 4. The exhaust pulse pipe 1 is used to transport the high-temperature exhaust gas generated by combustion in each cylinder of the engine to the turbocharger 8 to drive the turbocharger turbine in the turbocharger 8. The exhaust manifold 4 is the engine's exhaust manifold. The exhaust pulse pipe 1 of this utility model has a bypass outlet, and an exhaust gas bypass exhaust pipe assembly 2 is connected via this bypass outlet. The exhaust gas bypass exhaust pipe assembly 2 allows a portion of the high-temperature exhaust gas in the exhaust pulse pipe 1 to be diverted into the exhaust gas bypass exhaust pipe assembly 2. The exhaust gas bypass exhaust pipe assembly 2 is connected to an exhaust gas bypass valve 3, which can be opened or closed under the control of the control air circuit. The exhaust bypass valve 3 is connected to the main exhaust pipe 4, so that when the exhaust bypass valve 3 is opened, some of the high-temperature exhaust gas in the exhaust pulse pipe 1 can be discharged into the outside atmosphere sequentially through the exhaust bypass exhaust pipe assembly 2, the exhaust bypass valve 3, and the main exhaust pipe 4. Figure 6 As shown, the control air circuit of this utility model includes a control intake pipe L1 connected to the control intake port 32a of the exhaust gas bypass valve 3 and a control exhaust pipe L2 connected to the control exhaust port 32b of the exhaust gas bypass valve 3. An electric pressure regulating valve 5 is installed in the control intake pipe L1, and an electromagnetic relief valve 6 is installed in the control exhaust pipe L2. Both the electric pressure regulating valve 5 and the electromagnetic relief valve 6 are connected to the engine controller 7, i.e., the engine ECU control circuit. Based on the monitored pressure and speed signals of the turbocharger, the engine controller 7, after internal calculation, analysis, and processing, outputs control electrical signals to the electric pressure regulating valve 5 and the electromagnetic relief valve 6. Under the control of the engine controller 7, the electric pressure regulating valve 5 and the electromagnetic relief valve 6 work together to control the pressure of the control gas entering the exhaust gas bypass valve 3, thereby controlling the opening or closing of the exhaust gas bypass valve 3. By controlling the opening or closing of the exhaust bypass valve 3, and the degree to which the exhaust bypass valve 3 is open, the amount of high-temperature exhaust gas entering the turbocharger from the engine exhaust pipe can be adjusted and controlled, the turbocharger speed can be controlled, the turbocharger speed can be prevented from overspeeding, and the pressure of the boosted air can be controlled. In this way, the air-fuel ratio of the engine combustion is controlled and adjustable, and the engine performance can be optimized to the best point according to the needs of ship operation.

[0021] In this embodiment, the exhaust bypass pipe assembly 2 of this utility model is fixedly mounted on the housing of the engine intercooler 9 via an assembly bracket. Figure 2As shown, the exhaust bypass pipe assembly 2 consists of an exhaust bypass connecting pipe 21, a corrugated pipe 22, and an exhaust bypass bend 23 connected in sequence. The exhaust bypass connecting pipe 21 is a two-in-one connecting pipe that combines two branch pipes into one main pipe. Of course, the exhaust bypass connecting pipe 21 of this invention can also be a one-in-one, three-in-one, or multi-in-one connecting pipe depending on the number of turbocharger inlets. Here, this invention uses a two-in-one connecting pipe. The inlet ends of the two branch pipes of the exhaust bypass connecting pipe 21 are connected to the bypass outlet of the exhaust pulse pipe 1 via flanges and flange gaskets. Similarly, the exhaust bypass connecting pipe 21 and the corrugated pipe 22, as well as the corrugated pipe 22 and the exhaust bypass bend 23, are also sealed and connected via flanges and flange gaskets.

[0022] In this embodiment, the waste gas bypass valve 3 of this utility model is assembled from a valve housing 31, a valve cover plate 32, and a valve assembly. Figure 3 and Figure 5 As shown, the valve housing 31 is formed with an exhaust gas inlet 31a for connecting with the exhaust gas bypass bend 23, an exhaust gas outlet 31b for connecting with the main exhaust pipe 4, and an exhaust gas discharge channel 31c for connecting the exhaust gas inlet 31a and the exhaust gas outlet 31b. The exhaust gas discharge channel 31c bends at the bottom and then extends upward at an incline. A valve chamber 31d is also formed in the valve housing 31, which consists of a piston chamber with a larger diameter and a guide hole with a smaller diameter. The valve chamber 31d is coaxially connected to the exhaust gas inlet 31a. Figure 3 As can be seen, the valve assembly is located in the valve chamber 31d and can control the opening or closing of the exhaust gas inlet 31a. The valve cover plate 32 of this utility model is fitted with the cavity cover of the valve chamber 31d.

[0023] like Figure 3 As shown, the valve assembly of this utility model consists of a bypass valve stem 33, a valve stem guide 34, a valve spring 35, and a piston 36. The valve stem guide 34 is tightly fitted and positioned in the guide hole of the valve chamber 31d. The main function of the valve stem guide 34 is to provide guidance for the up-and-down movement of the bypass valve stem 33, ensuring the smooth movement of the bypass valve stem 33. The bypass valve stem 33 slides through the valve stem guide 34 and extends into the exhaust gas inlet 31a of the valve housing 31. The bottom of the bypass valve stem 33 is formed with a valve seat 331 for sealing and engaging with the exhaust gas inlet 31a. The piston 36 is positioned and mounted on the upper end of the bypass valve stem 33 by a locking nut M. The valve spring 35 is fitted onto the bypass valve stem 33 and located in the piston chamber of the valve chamber 31d. The upper end of the valve spring 35 abuts against the bottom surface of the piston 36, and the lower end of the valve spring 35 presses against the annular surface at the bottom of the piston chamber. The valve spring 35 is used to provide preload pressure for the sealing fit between the valve seat 331 and the exhaust inlet 31a.

[0024] In the embodiments, such as Figure 3and Figure 6 As shown, piston 36 is located in piston chamber, which divides piston chamber into spring chamber located at the lower part of piston 36 and working air chamber 31e located between piston 36 and valve cover plate 32. The control air inlet 32a and control exhaust outlet 32b of this invention are both located on valve cover plate 32 and connected to working air chamber 31e. Thus, when control gas enters working air chamber 31e, pressure is applied to piston 36. When the pressure in working air chamber 31e exceeds the spring force of valve spring 35, the control gas pushes bypass valve stem 33 to compress valve spring 35 downwards, thereby opening exhaust gas inlet 31a, allowing high-temperature exhaust gas to be discharged into exhaust manifold 4 through exhaust gas inlet 31a, exhaust gas discharge channel 31c, and exhaust gas outlet 31b. This invention utilizes the electrical signal of the engine controller 7 to control the electric pressure regulating valve 5 and the electromagnetic relief valve 6. The linkage of these two valves controls the air pressure value of the working air chamber 31e to adjust the stroke of the bypass valve rod 33. The stroke of the bypass valve rod 33 determines the amount of high-temperature exhaust gas emitted per unit time. A larger amount of high-temperature exhaust gas emitted results in a smaller amount of high-temperature exhaust gas entering the turbocharger, and vice versa.

[0025] To prevent control gas from flowing downwards into the spring chamber, a piston ring 37 is fitted onto the piston 36. If control gas or high-temperature exhaust gas flows into the spring chamber, specifically into the piston chamber located below the piston 36, this will increase the pressure within the spring chamber, affecting the opening pressure of the bypass valve stem 33 and reducing the valve's sensitivity. Therefore, if... Figure 5 As shown, the present invention also has a leakage air outlet X1 at the bottom of the piston chamber that is connected to the atmosphere, so that the gas leaking into the spring chamber can be directly discharged into the outside atmosphere through the leakage air outlet X1.

[0026] This invention also includes a valve seat ring 38 tightly fitted into the exhaust gas inlet 31a, with the valve seat 331 at the bottom of the bypass valve stem 33 sealingly fitted with the valve seat ring 38. Both the valve seat ring 38 and the valve stem guide 34 are made of wear-resistant, high-temperature-resistant, and corrosion-resistant materials, thus improving the overall service life of the valve. This invention utilizes the fit between the valve seat ring 38 and the valve seat 331 to prevent wear on the exhaust gas inlet 31a. To reduce the temperature of the valve seat ring 38 and prevent burning between the valve seat ring 38 and the bypass valve stem 33, ... Figure 5 As shown, a first cooling water chamber Q1 is provided between the outer peripheral surface of the valve seat 38 and the inner wall of the exhaust gas inlet 31a. The lower end of the valve housing 31 is provided with a first cooling water inlet 31f and a first cooling water outlet 31g for providing circulating cooling water to the first cooling water chamber Q1. When the circulating cooling water flows through the first cooling water chamber Q1, it can carry away the heat on the valve seat 38, thereby reducing the temperature of the valve seat 38.

[0027] In the embodiments, such as Figure 5 As shown, a cooling water jacket 39 is fitted onto the outer circumferential surface of the upper end of the valve housing 31, located in the moving area of ​​the piston 36. A second cooling water cavity Q2 is formed between the cooling water jacket 39 and the outer wall of the valve housing 31. The cooling water jacket 39 is provided with a second cooling water inlet 39a and a second cooling water outlet 39b for providing circulating cooling water to the second cooling water cavity Q2. Similarly, when the circulating cooling water flows through the second cooling water cavity Q2, it can carry away the heat generated on the valve housing 31 due to the movement of the piston.

[0028] In the embodiments, as shown Figure 4 As shown, a gap air chamber J1 is provided between the bypass valve stem 33 and the valve stem guide 34 of this utility model. Pressurized cooling air is introduced into the gap air chamber J1 to prevent exhaust gas from entering the gap between the bypass valve stem 33 and the valve stem guide 34 when the bypass valve stem 33 is working. The bypass valve stem 33 of this utility model operates in an intermittent mode. When the exhaust gas bypass valve 3 is working, exhaust gas may leak into the gap between the bypass valve stem 33 and the valve stem guide 34. Over time, this can easily lead to carbon buildup and jamming of the bypass valve stem 33. To address this, this utility model introduces pressurized cooling air to purge the gap between the bypass valve stem 33 and the valve stem guide 34 to prevent exhaust gas from entering, thereby ensuring the reliability and safety of the exhaust gas bypass valve 3 during operation.

[0029] like Figure 4 and Figure 5 As shown, the valve housing 31 of this utility model is provided with a pressurized cooling air inlet 31h, and the valve stem guide 34 is provided with a radial connecting hole 34a for connecting the pressurized cooling air inlet 31h and the gap air chamber J1; the bypass valve stem 33 is formed with an exhaust channel 33a for guiding the pressurized cooling air in the gap air chamber J1 into the exhaust gas discharge channel 31c of the valve housing 31. In the embodiment, from Figure 6 As can be seen, the exhaust channel 33a of this utility model consists of an upper radial channel formed on the bypass valve stem 33 to connect the gap air chamber J1, a lower radial channel located on the valve seat 331 to connect the exhaust gas discharge channel 31c, and a longitudinal channel for connecting the upper radial channel and the lower radial channel.

[0030] In the embodiments, such as Figure 6 As shown, the control gas in the control intake pipe L1 of this invention comes from a compressed air bottle, which is connected to the intake port of the control intake pipe L1. The exhaust port of the control exhaust pipe L2 is directly connected to the outside atmosphere. The cooling water in the first cooling water chamber Q1 and the second cooling water chamber Q2 comes from the engine's internal cooling water main; the pressurized cooling air comes from the engine's intercooler rear intake pipe.

[0031] The exhaust bypass structure of this utility model for high-power marine engines is also applicable to new energy Otto cycle gas engines. It can effectively control the air-fuel ratio to achieve high performance indicators, while also responding to the national carbon reduction and emission reduction policy.

[0032] The above embodiments provide a systematic and detailed description of the present utility model. These are merely preferred embodiments of the present utility model and are not intended to limit the present utility model. For those skilled in the art, the present utility model can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A waste gas bypass structure for a marine high-power engine, comprising an exhaust pulse pipe (1) connecting a turbocharger (8) and a main exhaust pipe (4); characterized in that: The exhaust pulse pipe (1) is bypassed to an exhaust bypass pipe assembly (2), which is connected to an exhaust bypass valve (3) controlled by a control air circuit. The exhaust bypass valve (3) is connected to the main exhaust pipe (4). The control air circuit includes a control intake pipe (L1) connected to the control intake port (32a) of the exhaust bypass valve (3) and a control exhaust pipe (32b) connected to the control exhaust port (3). The pipeline (L2) is equipped with an electric pressure regulating valve (5) in the intake control pipeline (L1) and an electromagnetic relief valve (6) in the exhaust control pipeline (L2). The electric pressure regulating valve (5) and the electromagnetic relief valve (6) are both connected to the engine controller (7) circuit. The controller (7) controls the opening and closing of the exhaust bypass valve (3) by controlling the electric pressure regulating valve (5) and the electromagnetic relief valve (6) with electrical signals, thereby adjusting the amount of high-temperature exhaust gas entering the turbocharger.

2. The exhaust bypass structure for a high-power marine engine according to claim 1, characterized in that: The exhaust bypass pipe assembly (2) is fixedly installed on the intercooler (9) of the engine via an assembly bracket. The exhaust bypass pipe assembly (2) consists of an exhaust bypass connecting pipe (21), a corrugated pipe (22), and an exhaust bypass bend (23) connected in sequence. The exhaust bypass connecting pipe (21) is a two-in-one connecting pipe that combines two branch pipes into one main pipe. The air inlet ends of the two branch pipes are connected to the bypass outlet of the exhaust pulse pipe (1) via flanges and flange gaskets.

3. The exhaust bypass structure for a high-power marine engine according to claim 2, characterized in that: The exhaust bypass valve (3) is assembled from a valve body (31), a valve cover plate (32), and a valve assembly. The valve body (31) is formed with an exhaust gas inlet (31a) for connecting with the exhaust bypass bend (23), an exhaust gas outlet (31b) for connecting with the exhaust main pipe (4), and an exhaust gas discharge channel (31c) for connecting the exhaust gas inlet (31a) and the exhaust gas outlet (31b). The valve body (31) is also formed with a valve chamber (31d) consisting of a piston chamber and a guide hole. The valve chamber (31d) is coaxially connected with the exhaust gas inlet (31a). The valve assembly is disposed in the valve chamber (31d) and can control the opening or closing of the exhaust gas inlet (31a). The valve cover plate (32) is fitted to the opening of the valve chamber (31d).

4. The exhaust bypass structure for a high-power marine engine according to claim 3, characterized in that: The valve assembly consists of a bypass valve stem (33), a valve stem guide (34), a valve spring (35), and a piston (36). The valve stem guide (34) is tightly fitted and positioned in the guide hole of the valve chamber (31d). The bypass valve stem (33) slides through the valve stem guide (34) and extends into the exhaust gas inlet (31a) of the valve body (31). The bottom of the bypass valve stem (33) is formed with a valve seat (331) for sealing and cooperating with the exhaust gas inlet (31a). The piston (36) is positioned and installed on the upper end of the bypass valve stem (33) by a locking nut (M). The valve spring (35) is fitted on the bypass valve stem (33) and located in the piston chamber of the valve chamber (31d). The upper end of the valve spring (35) abuts against the bottom surface of the piston (36), and the lower end of the valve spring (35) presses against the annular surface at the bottom of the piston chamber.

5. The exhaust bypass structure for a high-power marine engine according to claim 4, characterized in that: The piston chamber located between the piston (36) and the valve cover plate (32) constitutes the working gas chamber (31e); the control air inlet (32a) and the control exhaust port (32b) are both located on the valve cover plate (32) and communicate with the working gas chamber (31e); the piston (36) is fitted with a piston ring (37) to prevent the control gas from flowing downwards; the bottom of the piston chamber has a leakage air outlet (X1) that communicates with the atmosphere.

6. The exhaust bypass structure for a high-power marine engine according to claim 5, characterized in that: A valve seat ring (38) is tightly fitted in the exhaust gas inlet (31a), and the valve seat (331) at the bottom of the bypass valve stem (33) is sealed to the valve seat ring (38). A first cooling water chamber (Q1) for cooling the valve seat ring (38) is provided between the outer peripheral surface of the valve seat ring (38) and the inner wall of the exhaust gas inlet (31a). The lower end of the valve body (31) is provided with a first cooling water inlet (31f) and a first cooling water outlet (31g) for providing circulating cooling water to the first cooling water chamber (Q1).

7. The exhaust bypass structure for a high-power marine engine according to claim 6, characterized in that: A cooling water jacket (39) is fitted onto the outer peripheral surface of the upper end of the valve housing (31) and located in the active area of ​​the piston (36); a second cooling water chamber (Q2) is formed between the cooling water jacket (39) and the outer wall of the valve housing (31); the cooling water jacket (39) is provided with a second cooling water inlet (39a) and a second cooling water outlet (39b) for providing circulating cooling water to the second cooling water chamber (Q2).

8. The exhaust bypass structure for a high-power marine engine according to claim 7, characterized in that: A gap air chamber (J1) is provided between the bypass valve stem (33) and the valve stem guide (34). Pressurized cooling air is introduced into the gap air chamber (J1). The pressurized cooling air is used to prevent exhaust gas from entering the gap between the bypass valve stem (33) and the valve stem guide (34) when the bypass valve stem (33) is working.

9. The exhaust bypass structure for a high-power marine engine according to claim 8, characterized in that: The valve housing (31) is provided with a pressurized cooling air inlet (31h), and the valve stem guide (34) is provided with a radial connecting hole (34a) for connecting the pressurized cooling air inlet (31h) and the gap air chamber (J1); the bypass valve stem (33) is formed with an exhaust channel (33a) for guiding the pressurized cooling air in the gap air chamber (J1) into the exhaust gas discharge channel (31c) of the valve housing (31).

10. The exhaust bypass structure for a high-power marine engine according to claim 9, characterized in that: The control gas in the control intake pipe (L1) comes from a compressed air cylinder, which is connected to the intake port of the control intake pipe (L1); the exhaust port of the control exhaust pipe (L2) is connected to the outside atmosphere; the cooling water in the first cooling water chamber (Q1) and the second cooling water chamber (Q2) comes from the engine's internal cooling water main pipe; the pressurized cooling air comes from the engine's intercooler rear intake pipe.

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