V-shaped double-cylinder engine cooling system and engine

Abstract

The V-shaped double-cylinder engine cooling system comprises a main water channel, branch water channels and a water cooling jacket system, the water cooling jacket system comprises a front cylinder water cooling jacket and a rear cylinder water cooling jacket, and the branch water channels comprise a front cylinder branch water channel and a rear cylinder branch water channel. The front cylinder water-cooled jacket and the rear cylinder water-cooled jacket are respectively and correspondingly communicated with the main water channel through a front cylinder branch water channel and a rear cylinder branch water channel; the rear cylinder water cooling jacket is provided with a rear cylinder water inlet channel, and the rear cylinder water inlet channel is communicated with the rear cylinder water distribution channel and forms throttling on a communication channel. According to the V-shaped double-cylinder engine cooling system and the engine, the throttling structure is arranged at the water inlet position of the rear cylinder water-cooled jacket, so that a cooling medium entering the rear cylinder water-cooled jacket is guided and controlled, the flow speed and the flow direction of cooling liquid are effectively controlled, the cooling medium entering the front cylinder water-cooled jacket and the cooling medium entering the rear cylinder water-cooled jacket are rectified, and the service life of the engine is prolonged. The front cylinder body and the rear cylinder body of the V-shaped double-cylinder engine are cooled more uniformly, and the cooling effect of the whole engine is effectively improved.

Description

Technical Field

[0001] The utility model relates to a power device and its application, in particular to a V-type twin-cylinder engine cooling system and an engine. Background Art

[0002] The V-type twin-cylinder engine has the advantages of low-speed high torque and unique sound wave, and is widely used in cruiser motorcycles. The front cylinder and the rear cylinder of the V-type twin-cylinder engine are arranged in a V-type structure as a whole, and this special cylinder arrangement form increases the cooling difficulty of the engine.

[0003] The layout mode of staggered arrangement of the front and rear cylinders of the V-type twin-cylinder engine will cause differences in the flow path, flow velocity and flow rate of the coolant after entering the water jackets of the front and rear cylinders, thus causing local over-high heat load of the cylinder block. The V-shaped arrangement of the cylinders results in the inability to effectively utilize the airflow to cool the surface of the rear cylinder during riding, resulting in a higher temperature of the rear cylinder and increasing the risk of heat damage.

[0004] To solve the above problems, a cooling system is needed, which can effectively optimize the flow mode of the coolant to avoid uneven cooling of the cylinder blocks of the front and rear cylinders of the V-type twin-cylinder engine, improve the cooling effect of the whole engine, and reduce the risk of heat damage. Summary of the Utility Model

[0005] In view of this, the utility model provides a V-type twin-cylinder engine cooling system and an engine. By setting a throttling structure at the water inlet position of the rear cylinder water jacket, that is, on the connecting path between the rear cylinder water inlet channel and the rear cylinder water distribution channel, the cooling medium entering the rear cylinder water jacket is guided and controlled, the flow velocity and flow direction of the coolant are effectively controlled, a rectifying effect is formed on the cooling medium entering the front and rear cylinder water jackets, the cooling of the cylinder blocks of the front and rear cylinders of the V-type twin-cylinder engine is more uniform, and the cooling effect of the whole engine is effectively improved.

[0006] The utility model discloses a V-type twin-cylinder engine cooling system, which includes a main water channel, a water distribution channel and a water jacket system. The water jacket system includes a front cylinder water jacket and a rear cylinder water jacket. The water distribution channel includes a front cylinder water distribution channel and a rear cylinder water distribution channel. The front cylinder water jacket and the rear cylinder water jacket are respectively connected to the main water channel through the front cylinder water distribution channel and the rear cylinder water distribution channel. The rear cylinder water jacket is provided with a rear cylinder water inlet channel, and the rear cylinder water inlet channel is connected to the rear cylinder water distribution channel and forms a throttle on the connecting channel.

[0007] Further, the flow area at the connection position between the rear cylinder water inlet channel and the rear cylinder water distribution channel is reduced to form a throttle.

[0008] Further, the rear cylinder cooling channel is provided with a rear cylinder water inlet, the rear cylinder water distribution channel is provided with a rear cylinder water distribution channel water outlet, and the rear cylinder water inlet and the rear cylinder water distribution channel water outlet are joined together and radially offset to form a throttle.

[0009] Further, it further includes a thermostat, the thermostat is provided with a front cylinder thermostat inlet water pipe and a rear cylinder thermostat inlet water pipe, the front cylinder water cooling jacket is communicated with the front cylinder thermostat inlet water pipe, and the rear cylinder water cooling jacket is communicated with the rear cylinder thermostat inlet water pipe; in terms of the flow area, the front cylinder thermostat inlet water pipe is smaller than the rear cylinder thermostat inlet water pipe.

[0010] Further, the front cylinder water cooling jacket includes a front cylinder head water cooling jacket and a front cylinder block water cooling jacket. A front cylinder head cooling water channel is arranged in the front cylinder head water cooling jacket, a front cylinder block cooling water channel is arranged in the front cylinder block water cooling jacket, and a plurality of front cylinder water passing holes for communicating the front cylinder head cooling water channel with the front cylinder block cooling water channel are arranged at the joint surface of the front cylinder block water cooling jacket and the front cylinder head water cooling jacket.

[0011] The rear cylinder water cooling jacket includes a rear cylinder head water cooling jacket and a rear cylinder block water cooling jacket. A rear cylinder head cooling water channel is arranged in the rear cylinder head water cooling jacket, a rear cylinder block cooling water channel is arranged in the rear cylinder block water cooling jacket, and a plurality of rear cylinder water passing holes for communicating the rear cylinder head cooling water channel with the rear cylinder block cooling water channel are arranged at the joint surface of the rear cylinder block water cooling jacket and the rear cylinder head water cooling jacket.

[0012] Further, a plurality of axially penetrating throttling grooves are arranged in both the front cylinder block water cooling jacket and the rear cylinder block water cooling jacket, and the radial cross-section of the throttling groove is in a semi-circular structure;

[0013] Drainage grooves are arranged at the bottoms of both the front cylinder block water cooling jacket and the rear cylinder block water cooling jacket. The height of the drainage groove of the front cylinder block water cooling jacket is 30%-50% of the height of the front cylinder block water cooling jacket; the height of the drainage groove of the rear cylinder block water cooling jacket is 30%-50% of the height of the rear cylinder block water cooling jacket.

[0014] Further, a front cylinder water inlet channel is arranged in the front cylinder block water cooling jacket, and a front cylinder water outlet channel is arranged in the front cylinder head water cooling jacket. The front cylinder block water cooling jacket is communicated with the front cylinder water distribution channel through the front cylinder water inlet channel; the front cylinder head water cooling jacket is communicated with the front cylinder thermostat inlet water pipe through the front cylinder water outlet channel;

[0015] The rear cylinder water inlet channel is arranged in the rear cylinder block water cooling jacket, and a rear cylinder water outlet channel is arranged in the rear cylinder head water cooling jacket; the rear cylinder head water cooling jacket is communicated with the rear cylinder thermostat inlet water pipe through the rear cylinder water outlet channel;

[0016] Further, the thermostat further includes a housing, a thermostat valve, a thermostat water outlet I, and a thermostat water outlet II. The thermostat valve is disposed within the housing. The thermostat water outlet II, the front cylinder thermostat inlet pipe, and the rear cylinder thermostat inlet pipe are installed on the housing and communicate with the front of the valve of the thermostat valve; the thermostat water outlet I is disposed on the housing and communicates with the rear of the valve of the thermostat valve.

[0017] Further, it further includes a cooling water pump and a radiator; the cooling water pump has a water pump inlet and a water pump outlet, the radiator is provided with a radiator inlet and a radiator outlet, the water pump outlet communicates with the main water channel, the water pump inlet communicates with the radiator outlet and the thermostat water outlet II, and the radiator inlet communicates with the thermostat water outlet I.

[0018] The present utility model also discloses an engine, and this engine is equipped with the V-type twin-cylinder engine cooling system as described above, and the main water channel is integrally formed on the engine.

[0019] Advantages of the present utility model:

[0020] In the V-type twin-cylinder engine cooling system and the engine disclosed by the present utility model, by providing a throttling structure at the water inlet position of the rear cylinder water-cooling jacket, that is, on the communication path between the rear cylinder water inlet channel and the rear cylinder water distribution channel, the cooling medium entering the rear cylinder water-cooling jacket is guided and controlled, effectively controlling the flow rate and flow direction of the coolant, forming a rectifying effect on the cooling medium entering the front and rear cylinder water-cooling jackets, cooling the front and rear cylinder blocks of the V-type twin-cylinder engine more evenly, and effectively improving the cooling effect of the entire engine;

[0021] The provided throttling grooves and drainage grooves enable there to be no flow dead zones after the coolant enters the cylinder block water jacket, and ensure that there is sufficient flow at both the top and bottom of the cylinder block water jacket, thereby improving the flow effect; by adjusting the flow area of the front cylinder thermostat inlet pipe and the rear cylinder thermostat inlet pipe, the flow rate of the cooling medium in the rear cylinder is effectively increased.

[0022] The present utility model optimizes the structures of the water-cooling jacket system and the thermostat, making the flow paths of the cooling media in the front and rear cylinders the same, and making the flow of the cooling media inside the water-cooling jackets of each cylinder more uniform, with a better heat dissipation effect. At the same time, the flow rate of the coolant in the rear cylinder water jacket is effectively increased, and the temperature of the rear cylinder of the V-cylinder engine is effectively reduced. Brief Description of the Drawings

[0023] Figure 1 is a schematic structural diagram of the system of the present utility model;

[0024] Figure 2 is an exploded view of the assembled structure of the water-cooling jacket system, the main water channel, and the thermostat of the present utility model;

[0025] Figure 3Schematic assembly structure diagram of the water-cooling jacket system, main water channel and thermostat of the present utility model;

[0026] Figure 4 Schematic diagram of the connection structure between the rear cylinder water inlet channel and the rear cylinder water distribution channel Figure Ⅰ ;

[0027] Figure 5 Schematic diagram of the connection structure between the rear cylinder water inlet channel and the rear cylinder water distribution channel Figure Ⅱ ;

[0028] Figure 6 Isometric view of the connection structure between the water-cooling jacket system and the main water channel of the present utility model;

[0029] Figure 7 Side view of the connection structure between the water-cooling jacket system and the main water channel of the present utility model

[0030] Figure 8 Schematic diagram of the arrangement of water passing holes in the water-cooling jacket of the rear cylinder block of the present utility model;

[0031] Figure 9 Schematic structure diagram of the water-cooling jacket of the rear cylinder head of the present utility model. Detailed implementation manners

[0032] It should be noted that in the description of this specification, the orientation or positional relationship indicated by terms such as "upper", "lower", "top", "bottom", "inner", "outer", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, so it cannot be understood as a limitation to the present utility model. Without special instructions, the front and rear in this embodiment refer to the forward direction of the vehicle, that is, the front cylinder is the engine cylinder block located on the front side in the forward direction of the vehicle.

[0033] As shown in the figure, this embodiment discloses a V-type twin-cylinder engine cooling system, which includes a main water channel 5, a branch water channel, and a water jacket system 1. The water jacket system 1 includes a front cylinder water jacket and a rear cylinder water jacket. The branch water channel includes a front cylinder branch water channel 11 and a rear cylinder branch water channel 10. The front cylinder water jacket and the rear cylinder water jacket are respectively connected to the main water channel 5 through the front cylinder branch water channel 11 and the rear cylinder branch water channel 10. The rear cylinder water jacket is provided with a rear cylinder water inlet channel 12, and the rear cylinder water inlet channel 12 is connected to the rear cylinder branch water channel 10 and forms a throttle on the connecting channel. In this embodiment, the rear cylinder water jacket is connected to the rear cylinder branch water channel 10 through the rear cylinder water inlet channel 12, and then communicates with the main water channel 5. After the rear cylinder water inlet channel 12 and the cylinder branch water channel are connected, a connecting channel for the cooling medium to enter the rear cylinder water jacket is formed. After a throttle structure is formed by setting a throttle at this connecting channel, when the cooling medium flows, it will not flow directly upward along a straight line like the traditional structure. Instead, when it flows into the throttle position, the flow area gradually decreases, and then increases after passing through this throttle position, so that the cooling medium is effectively guided to flow divergently along the circumferential and axial directions of the rear cylinder water jacket, the flow is more uniform, and the water flow is more stable. As a result, the cooling effect of the rear cylinder water jacket is greatly improved.

[0034] In this embodiment, the flow area at the connection position between the rear cylinder water inlet channel 12 and the rear cylinder branch water channel 10 is reduced to form a throttle. In this embodiment, the rear cylinder cooling channel is provided with a rear cylinder water inlet, and the rear cylinder branch water channel 10 is provided with a rear cylinder branch water channel 10 water outlet. The rear cylinder water inlet and the rear cylinder branch water channel 10 water outlet are mutually joined and radially offset to form a throttle. In this embodiment, the throttle position is set at the connection position between the rear cylinder water inlet channel 12 and the rear cylinder branch water channel 10, that is, on the joint surface of the aforementioned two, and a throttle is formed by reducing the flow area at this position. The method of reducing the flow area at this position can be to form a flange by extending radially inward at the position of the rear cylinder branch water channel 10 water outlet to achieve the purpose of throttling, or directly set a gasket at the connection position between the rear cylinder water inlet channel 12 and the rear cylinder branch water channel 10 to make the flow area at this place suddenly decrease to achieve the purpose of throttling, as Figure 4 shown. In this embodiment, a throttle structure is formed by mutually attaching the rear cylinder water inlet and the rear cylinder branch water channel 10 water outlet and radially offsetting them during assembly, as Figure 5 shown; this method is simple to operate, can reduce the number of parts, and has obvious effects.

[0035] In this embodiment, a thermostat 2 is further included. The thermostat 2 is provided with a front cylinder thermostat inlet pipe 202 and a rear cylinder thermostat inlet pipe 201. The front cylinder water-cooling jacket is communicated with the front cylinder thermostat inlet pipe 202, and the rear cylinder water-cooling jacket is communicated with the rear cylinder thermostat inlet pipe 201. In terms of the flow area, the front cylinder thermostat inlet pipe 202 is smaller than the rear cylinder thermostat inlet pipe 201. In this embodiment, the coolant flow rate of each cylinder is adjusted by adjusting the flow areas of the front cylinder thermostat inlet pipe 202 and the rear cylinder thermostat inlet pipe 201. In this embodiment, the outer diameters of the front cylinder thermostat inlet pipe 202 and the rear cylinder thermostat inlet pipe 201 are the same, but the inner diameter of the front cylinder thermostat inlet pipe 202 is smaller than that of the rear cylinder thermostat inlet pipe 201 to reduce the coolant flow rate entering the front cylinder water jacket, further realizing the function of controlling the flow distribution ratio of the front and rear cylinders.

[0036] In this embodiment, the front cylinder water-cooling jacket includes a front cylinder head water-cooling jacket 9 and a front cylinder block water-cooling jacket 8. A front cylinder head cooling water channel is provided in the front cylinder head water-cooling jacket 9, and a front cylinder block cooling water channel is provided in the front cylinder block water-cooling jacket 8. And at the joint surface of the front cylinder block water-cooling jacket 8 and the front cylinder head water-cooling jacket 9, a plurality of front cylinder water passing holes for communicating the front cylinder head cooling water channel with the front cylinder block cooling water channel are provided.

[0037] The rear cylinder water-cooling jacket includes a rear cylinder head water-cooling jacket 7 and a rear cylinder block water-cooling jacket 6. A rear cylinder head cooling water channel is provided in the rear cylinder head water-cooling jacket 7, and a rear cylinder block cooling water channel is provided in the rear cylinder block water-cooling jacket 6. And at the joint surface of the rear cylinder block water-cooling jacket 6 and the rear cylinder head water-cooling jacket 7, a plurality of rear cylinder water passing holes for communicating the rear cylinder head cooling water channel with the rear cylinder block cooling water channel are provided. The structures of the front cylinder water-cooling jacket and the rear cylinder water-cooling jacket in this embodiment are the same, only the installation positions and the connection modes with the main water channel 5 are different. Now, taking the rear cylinder water-cooling jacket as an example to describe the structure, the description of the front cylinder water-cooling jacket will not be repeated. As shown in the figure, at the joint surface (corresponding to the axial top surface of the rear cylinder block water jacket and the axial bottom surface of the rear cylinder block water jacket in this embodiment) of the rear cylinder block water-cooling jacket 6 and the rear cylinder head water-cooling jacket 7, a total of 5 water passing holes are provided. The water passing hole Ⅰ16 and the water passing hole Ⅱ17 are process holes for quickly discharging the gas in the cylinder block water jacket. The water passing hole Ⅳ19 is the main water passing hole, and its water passing area should be as large as possible under the condition of meeting the process requirements. The water passing hole Ⅲ18 and the water passing hole Ⅴ20 are used for auxiliary water supply.

[0038] In this embodiment, the front cylinder block water-cooling jacket 8 and the rear cylinder block water-cooling jacket 6 are both provided with a plurality of throttling grooves 15 that penetrate axially. The radial cross-section of the throttling groove 15 is in a semi-circular structure. As shown in the figure, taking the rear cylinder block water-cooling jacket 6 as an example, there are two throttling grooves 15, which are distributed on both sides of the rear cylinder block water-cooling jacket 6A and B (the A and B sides here are artificially defined and set for the convenience of describing and understanding this solution in the attached drawings, which can be understood by those skilled in the art of this technology). The two semi-cylindrical throttling grooves 15 force part of the coolant to flow towards the bottom of the cylinder block water jacket by controlling the thickness of the wall surface of the rear cylinder block water-cooling jacket 6, thereby making the cooling of the bottom and top of the cylinder more uniform. On the premise that the wall thickness of the water jacket at the throttling groove 15 meets the processing requirements, the smaller the wall thickness, the better the throttling effect.

[0039] Drainage grooves 14 are provided at the bottoms of both the front cylinder block water-cooling jacket 8 and the rear cylinder block water-cooling jacket 6. The height of the drainage groove 14 of the front cylinder block water-cooling jacket 8 is 30%-50% of the height of the front cylinder block water-cooling jacket 8; the height of the drainage groove 14 of the rear cylinder block water-cooling jacket 6 is 30%-50% of the height of the rear cylinder block water-cooling jacket 6. As Figure 8 shown, taking the rear cylinder block water-cooling jacket 6 as an example, the rear cylinder block water-cooling jacket 6 is provided with an arc-shaped drainage groove 14. The drainage groove 14 is located below the exhaust bridge 22, and its main function is to guide the coolant on both sides of the A and B in the main water channel 5 of the cylinder block water jacket to the cylinder head water jacket, as shown in the figure. The height of this drainage groove 14 should account for 30%-50% of the height of the rear cylinder block water-cooling jacket 6. If the height is too small, a flow dead zone will be caused due to the convergence of the coolant, and if it is too large, local high temperature will be caused due to insufficient cooling.

[0040] In this embodiment, whether it is the front cylinder water-cooling jacket or the rear cylinder water-cooling jacket, the corresponding cylinder head water-cooling jacket and cylinder block water-cooling jacket both adopt a "surrounding type" coolant flow path, that is: a flow mode of first diverging and then converging, that is, the cooling flow path is in a surrounding and enclosing structure. As Figure 2 shown; and the coolant mainly enters the rear cylinder head water-cooling jacket 7 from the water passing hole Ⅳ19, and is diverted in the area of the exhaust bridge 22 of the engine, and finally converges from one side of the intake bridge 21 and flows into the thermostat 2 from the rear cylinder outlet channel 701 of the rear cylinder head water-cooling jacket 7. An arc-shaped drainage groove 24 and a trapezoidal throttling groove 23 as shown in the figure are also provided on the rear cylinder head water-cooling jacket 7 to increase Figure 9 the flow rate and velocity in area C.

[0041] In this embodiment, the front cylinder block water jacket 8 is provided with a front cylinder water inlet passage 13, and the front cylinder head water jacket 9 is provided with a front cylinder water outlet passage 901. The front cylinder block water jacket 8 is communicated with the front cylinder water distribution channel 11 through the front cylinder water inlet passage 13; the front cylinder head water jacket 9 is communicated with the front cylinder thermostat inlet pipe 202 through the front cylinder water outlet passage 901; the rear cylinder water inlet passage 12 is arranged in the rear cylinder block water jacket 6, and the rear cylinder head water jacket 7 is provided with a rear cylinder water outlet passage 701; the rear cylinder head water jacket 7 is communicated with the rear cylinder thermostat inlet pipe 201 through the rear cylinder water outlet passage 701. In this embodiment, the thermostat 2 further includes a housing, a thermostat valve 205, a thermostat water outlet I 203 and a thermostat water outlet II 204. The thermostat valve 205 is arranged in the housing to separate the housing. The thermostat water outlet II 204, the front cylinder thermostat inlet pipe 202 and the rear cylinder thermostat inlet pipe 201 are installed on the housing and communicated with the front of the valve of the thermostat valve 205; the thermostat water outlet I 203 is arranged on the housing and communicated with the rear of the valve of the thermostat valve 205. In this embodiment, the front and rear of the valve are determined according to the flow direction of the cooling medium. The side where the cooling medium flows in is the front side of the thermostat valve 205, that is, the front of the valve, which can be understood by those skilled in the art of the present technology and will not be elaborated here.

[0042] In this embodiment, a cooling water pump 4 and a radiator 3 are further included; the cooling water pump 4 has a water pump inlet and a water pump outlet. The radiator 3 is provided with a radiator 3 inlet and a radiator 3 outlet. The water pump outlet is communicated with the main water channel 5. The water pump inlet is communicated with the radiator 3 outlet and the thermostat water outlet II 204. The radiator 3 inlet is communicated with the thermostat water outlet I 203. The water jacket system 1, the thermostat 2, the cooling water pump 4 and the radiator 3 in this embodiment are interconnected to form a cooling system as shown in the figure. Among them, the large circulation loop of the cooling system is: cooling water pump 4 → water jacket system 1 → thermostat 2 → radiator 3 → cooling water pump 4; the small circulation loop of the cooling system is: cooling water pump 4 → water jacket system 1 → thermostat 2 → cooling water pump 4; the large and small circulations are controlled by the thermostat 2.

[0043] In this embodiment, the function of the two water distribution channels is to connect the main water channel 5 and the front and rear cylinder block water jackets 6, so that the coolant flows through the main water channel 5 after flowing out of the water pump and enters the front and rear cylinder water jackets respectively. In addition, the connection area between the water distribution channel and the main water channel 5 can be changed to control the flow distribution ratio between the front and rear cylinders. There are two ways to control the connection area between the water distribution channel and the main water channel 5: (1) Reduce the cross-sectional area of the front cylinder water distribution channel 11 relative to the rear cylinder water distribution channel 10; (2) Reduce the length of the front cylinder water distribution channel 11. The latter is adopted in this embodiment.

[0044] The present utility model also discloses an engine, which is equipped with the V-type twin-cylinder engine cooling system as described above. In this embodiment, the main water channel 5 of the cooling system is integrally formed in the engine. Integrating the main water channel 5 into the engine block can further simplify the structure, reduce the assembly difficulty, and make the whole engine structure more compact.

[0045] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present utility model and not to limit them. Although the present utility model has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present utility model can be modified or equivalently replaced without departing from the purpose and scope of the technical solutions of the present utility model, and they should all be covered by the scope of the claims of the present utility model.

Claims

1. A V-twin engine cooling system, characterized in that: It includes a main water channel, a water branch channel and a water cooling jacket system, wherein the water cooling jacket system includes a front cylinder water cooling jacket and a rear cylinder water cooling jacket, the water branch channel includes a front cylinder water branch channel and a rear cylinder water branch channel, the front cylinder water cooling jacket and the rear cylinder water cooling jacket are connected with the main water channel through the front cylinder water branch channel and the rear cylinder water branch channel respectively; the rear cylinder water cooling jacket is provided with a rear cylinder water inlet channel, the rear cylinder water inlet channel is connected with the rear cylinder water branch channel and throttling is formed on the connecting channel.

2. The V-twin engine cooling system according to claim 1, characterized in that: The flow area at the connection position between the rear cylinder water inlet channel and the rear cylinder water distribution channel is reduced to form throttling.

3. The V-twin engine cooling system according to claim 2, characterized in that: The rear cylinder cooling channel is provided with a rear cylinder water inlet, and the rear cylinder water branch channel is provided with a rear cylinder water branch channel outlet. The rear cylinder water inlet and the rear cylinder water branch channel outlet are engaged with each other and are radially staggered to form throttling.

4. The V-twin engine cooling system according to claim 1, characterized in that: It also includes a thermostat, which is provided with a front cylinder thermostat water inlet pipe and a rear cylinder thermostat water inlet pipe, the front cylinder water cooling jacket is connected to the front cylinder thermostat water inlet pipe, and the rear cylinder water cooling jacket is connected to the rear cylinder thermostat water inlet pipe; in terms of flow area, the front cylinder thermostat water inlet pipe is smaller than the rear cylinder thermostat water inlet pipe.

5. The V-twin engine cooling system according to claim 4, characterized in that: The front cylinder water cooling jacket comprises a front cylinder head water cooling jacket and a front cylinder body water cooling jacket, the front cylinder head water cooling jacket is provided with a front cylinder head cooling water channel, the front cylinder body water cooling jacket is provided with a front cylinder body cooling water channel, and a plurality of front cylinder water holes are provided at the joint surface of the front cylinder body water cooling jacket and the front cylinder head water cooling jacket to connect the front cylinder head cooling water channel with the front cylinder body cooling water channel; The rear cylinder water cooling jacket comprises a rear cylinder head water cooling jacket and a rear cylinder body water cooling jacket, wherein the rear cylinder head water cooling jacket is provided with a rear cylinder head cooling water channel, wherein the rear cylinder body water cooling jacket is provided with a rear cylinder body cooling water channel, and a plurality of rear cylinder water holes are provided at the joint surface of the rear cylinder body water cooling jacket and the rear cylinder head water cooling jacket to connect the rear cylinder head cooling water channel with the rear cylinder body cooling water channel.

6. The V-twin engine cooling system according to claim 5, characterized in that: The front cylinder water cooling jacket and the rear cylinder water cooling jacket are both provided with a plurality of throttling grooves penetrating in the axial direction, and the radial cross section of the throttling groove is a semicircular structure; The bottom of the front cylinder water cooling jacket and the bottom of the rear cylinder water cooling jacket are both provided with drainage grooves, and the height of the drainage groove of the front cylinder water cooling jacket is 30%-50% of the height of the front cylinder water cooling jacket; the height of the drainage groove of the rear cylinder water cooling jacket is 30%-50% of the height of the rear cylinder water cooling jacket.

7. The V-twin engine cooling system according to claim 5, characterized in that: The front cylinder body water cooling jacket is provided with a front cylinder water inlet channel, and the front cylinder head water cooling jacket is provided with a front cylinder water outlet channel. The front cylinder body water cooling jacket is connected with the front cylinder water branch channel through the front cylinder water inlet channel; the front cylinder head water cooling jacket is connected with the front cylinder thermostat water inlet pipe through the front cylinder water outlet channel; The rear cylinder water inlet channel is arranged on the rear cylinder body water cooling jacket, and the rear cylinder head water cooling jacket is provided with a rear cylinder water outlet channel; the rear cylinder head water cooling jacket is connected with the rear cylinder thermostat water inlet pipe through the rear cylinder water outlet channel.

8. The V-twin engine cooling system according to claim 4, characterized in that: The thermostat also includes a shell, a thermostat valve, a thermostat water outlet I and a thermostat water outlet II. The thermostat valve is arranged in the shell, and the thermostat water outlet II, the front cylinder thermostat water inlet pipe and the rear cylinder thermostat water inlet pipe are installed in the shell and connected to the front of the thermostat valve; the thermostat water outlet I is arranged in the shell and connected to the back of the thermostat valve.

9. The V-twin engine cooling system according to claim 8, characterized in that: It also includes a cooling water pump and a radiator; the cooling water pump has a water pump inlet and a water pump outlet, the radiator is provided with a radiator inlet and a radiator outlet, the water pump outlet is connected to the main water channel, the water pump inlet is connected to the radiator outlet and thermostat water outlet II, and the radiator inlet is connected to the thermostat water outlet I.

10. An engine equipped with a V-twin engine cooling system according to any one of claims 1 to 9, characterized in that: The main water channel is integrally formed with the engine.

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