A pressure balance structure for a two-cylinder engine

Abstract

The present invention provides a pressure balancing structure of a two-cylinder engine, belonging to the technical field of motorcycles. It solves the technical problem of large power loss in existing two-cylinder engines. The pressure balancing structure of the two-cylinder engine comprises a cylinder body and a crankcase, wherein the cylinder body has two cylinder barrels arranged side by side, and the crankcase has a vertically arranged support wall, which divides the inner cavity of the crankcase into two cavities, and the two cavities are respectively opposite to and connected with the two cylinder barrels above, and the pressure balancing structure comprises a lower air vent located on the side of the support wall and / or an upper air vent located between the support wall and the cylinder body, and the upper air vent and the lower air vent can both connect the two cavities. The present invention effectively balances the pressure fluctuation between the two cylinder barrels, improves the transmission efficiency and reduces the oil consumption.

Description

Technical Field

[0001] The invention belongs to the technical field and relates to a pressure balancing structure of a two-cylinder engine. Background Art

[0002] A motorcycle engine is a machine that ignites the fuel mixture that enters the cylinder, converts the heat energy generated by its combustion into mechanical energy, and transmits the power to the rear wheel of the motorcycle through the transmission mechanism via the crankshaft, thereby converting it into the driving force of the vehicle.

[0003] For example, a Chinese patent application with application publication number CN105781673A discloses a structure of an internal combustion engine, which includes a crankcase with a crankshaft chamber, a gear case with a speed gear set, and a cylinder block assembled on the crankcase, and a cylinder head with a valve chamber for installing a valve mechanism assembled on the cylinder body, wherein the crankcase and the gear case are independent cases with respective outer walls, wherein the gear case is provided with a blow-by gas passage, and a one-way valve that only allows oil and gas to flow from the crankcase to the gear case is provided on an exhalation channel connecting the crankcase and the non-oil-immersed part of the gear case.

[0004] The above internal combustion engine structure releases the high-temperature oil and gas pressure by setting up the exhalation channel and simplifies the internal combustion engine structure. However, when the piston of the internal combustion engine moves up and down during operation, it will be affected by the large air resistance inside the crankcase, resulting in power loss. To improve the above problems, ordinary technicians in this field can easily consider: 1. Setting a pressure relief valve and an air intake valve connected to the outside world on the side wall of the crankshaft cavity corresponding to the cylinder barrel; 2. Improving the lubrication effect of the engine oil on the piston to reduce the movement resistance. Summary of the invention

[0005] In view of the above problems existing in the prior art, the present invention provides a pressure balancing structure for a two-cylinder engine. The technical problem to be solved by the present invention is: how to improve the working efficiency of the engine.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] A pressure balancing structure for a two-cylinder engine, the engine comprising a cylinder block and a crankcase, the cylinder block having two cylinder barrels arranged side by side, the crankcase having a vertically arranged support wall, the support wall dividing the inner cavity of the crankcase into two cavities, the two cavities respectively facing and connected with the two cylinder barrels above, characterized in that the pressure balancing structure comprises a lower air vent located on the side of the support wall and / or an upper air vent located between the support wall and the cylinder block, the upper air vent and the lower air vent both being able to connect the two cavities.

[0008] There is a cylinder barrel inside the cylinder body for cooperating with the piston. The piston reciprocates along the axial direction of the cylinder barrel during stroke movement. The crankcase is located below the cylinder body. A vertically arranged support wall is arranged in the crankcase to provide support for the crankshaft rotatably connected to the piston connecting rod to ensure stable rotation, and can also provide support for the cylinder body at the same time. Multiple cylinder barrels can increase the engine displacement and make the engine work more stably. The support wall divides the inner cavity of the crankcase into two cavities and is directly opposite to the cylinder barrel above. In this way, the support position of the support wall is just between the two barrels to ensure uniform load. By arranging a lower air vent on the side of the supporting wall and / or an upper air vent between the supporting wall and the cylinder body, and connecting the two cavities through the lower air vent and the upper air vent, when the engine is working, the two pistons are in different stroke states and positions. When the piston moves downward, it squeezes the air in the lower cavity to form high pressure, and the piston next to it will enter an upward state to extract the air in the corresponding cavity to form negative pressure, so that the pressure fluctuation formed by the two cylinders is very small, and the air between the positive pressure and negative pressure cavities can be quickly exchanged through the air vent to meet the overall pressure balance, thereby reducing the resistance to the piston movement and improving the transmission efficiency. In addition, it avoids excessive pressure fluctuations in the cavity, causing the oil to atomize and then invade the piston fitting to affect the oil-gas separation effect of the combustion chamber, and also reduces the oil consumption.

[0009] In the pressure balance structure of the above two-cylinder engine, the engine also includes a gearbox, and the inner wall of the crankcase has an air expansion hole connected to the gearbox. The engine is also provided with a gearbox, which is used to assemble a speed change mechanism. By providing an air expansion hole connected to the gearbox on the inner wall of the crankcase, the crankcase and the gearbox are connected to increase the volume of the air pressure change caused by the piston movement, that is, the pressure change generated in the crankcase when the piston moves up or down will be better distributed, making the pressure fluctuation smaller, further reducing the resistance of the piston movement, ensuring the oil-gas separation effect and improving the engine efficiency.

[0010] In the pressure balance structure of the two-cylinder engine, the top of the support wall has a notch, and the upper vent hole is formed between the notch and the cylinder body. By setting the notch at the top of the support wall, an upper vent hole is formed between the notch and the lower end of the cylinder body, the notch processing is more convenient, and the upper vent hole formed between the notch and the cylinder body is closer to the lower end of the cylinder barrel. When the piston inhales or squeezes out air, it can more efficiently exchange air with the adjacent cavity, reduce excessive impact on the air pressure in the cavity, reduce pressure fluctuations, and improve engine efficiency.

[0011] In the pressure balance structure of the two-cylinder engine, the lower end of the cylinder barrel protrudes from the lower surface of the cylinder body, and the lower end of the cylinder barrel is located in the notch and the upper vent hole is formed between the notch. By setting the lower end of the cylinder barrel protruding from the lower surface of the cylinder body, and making the lower end of the cylinder barrel located in the notch and the upper vent hole formed between the notch, the upper vent hole is further formed between the lower end of the cylinder barrel and the notch, ensuring that the upper vent hole directly and efficiently exchanges the air in the cylinder barrel.

[0012] In the pressure balance structure of the above two-cylinder engine, the side edge of the support wall has the lower vent hole, and there are several expansion holes, at least one of which is located at the junction of the inner side wall of the crankcase and the support wall and is connected to the lower vent hole there, and the expansion hole there is connected to the cavities on both sides of the support wall. By setting the lower vent hole on the side edge of the support wall, setting the expansion hole at the junction of the inner side wall of the crankcase and the side of the support wall to connect and communicate with the lower vent hole there, when the air pressure in the cavity changes due to the movement of the piston, the air can be exchanged through the expansion hole and the lower vent hole at the same time, and the flow cross-sectional area between the gear box and the adjacent cavity is larger, which is conducive to the rapid and applicable exchange of air, and further ensures the pressure balance effect.

[0013] In the pressure balance structure of the two-cylinder engine, the inner edge of the air expansion hole and the inner edge of the lower air vent are both rounded. By setting the inner edge of the air expansion hole and the inner edge of the lower air vent to be rounded, it is ensured that the resistance of air is smaller and smoother when flowing through the air expansion hole and the lower air vent, thereby ensuring pressure balance and improving engine efficiency.

[0014] In the pressure balance structure of the above two-cylinder engine, the crankcase includes an upper case body and a lower case body that are fixedly connected, and the air expansion hole and the lower air vent hole are both located at the junction of the upper case body and the lower case body. By setting the crankcase to include an upper case body and a lower case body that are fixedly connected, the air expansion hole and the lower air vent hole are both located at the junction of the upper case body and the lower case body, which is conducive to separate processing and grooving, and can reduce the difficulty of the process. In addition, the lower air vent hole and the air expansion hole are located at the middle of the crankcase height, and the pressure balance effect will not be affected by the engine oil.

[0015] In the pressure balance structure of the two-cylinder engine, a plurality of the air expansion holes are arranged at intervals along the inner wall of the crankcase, and each of the cavities is connected to the gearbox through at least one of the air expansion holes. By arranging a plurality of air expansion holes at intervals along the inner wall of the crankcase, and making each cavity connected to the gearbox through at least one air expansion hole, it is ensured that the air exchange between each cavity and the gearbox is relatively uniform, which is beneficial to the pressure balance effect.

[0016] Compared with the prior art, the advantages of the present invention are as follows:

[0017] The pressure balance structure of the two-cylinder engine is achieved by arranging upper air vents and lower air vents that communicate with both sides of the supporting wall on the side surfaces of the supporting wall and between the supporting wall and the cylinder body. When the engine is working, the air between the positive pressure cavity and the negative pressure cavity can be quickly exchanged through the upper air vents and the lower air vents, thereby reducing the resistance to the movement of the piston and improving the transmission efficiency. In addition, it also avoids excessive pressure fluctuations in the cavity that cause the oil to atomize and then invade the piston fitting to affect the oil-gas separation effect of the combustion chamber. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the three-dimensional structure of this embodiment.

[0019] Figure 2 It is a schematic diagram of the explosion structure of this embodiment.

[0020] Figure 3 It is a schematic diagram of the three-dimensional structure of the crankcase and the gearbox in this embodiment.

[0021] Figure 4 yes Figure 3 Enlarged view of part A in .

[0022] Figure 5 It is a schematic diagram of the exploded structure of the crankcase and the gearbox in this embodiment.

[0023] Figure 6 It is a schematic diagram of the three-dimensional structure of the cylinder body and the upper box body in this embodiment.

[0024] Figure 7 yes Figure 6 Enlarged view of part B.

[0025] In the figure, 1, cylinder body; 11, cylinder barrel;

[0026] 2. crankcase; 21. cavity; 22. upper case; 23. lower case;

[0027] 3. Support wall; 31. Notch;

[0028] 4. Upper vent hole; 5. Gear box; 6. Air expansion hole; 7. Lower vent hole. DETAILED DESCRIPTION

[0029] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.

[0030] like Figure 1-7As shown, the pressure balance structure of the twin-cylinder engine includes a cylinder body 1 and a crankcase 2. The crankcase 2 has a vertically arranged support wall 3. The cylinder body 1 has two cylinder barrels 11 arranged side by side. The side of the support wall 3 and the support wall 3 and the cylinder body 1 respectively have a lower vent hole 7 and an upper vent hole 4 connected to the cavities 21 on both sides of the support wall 3. The support wall 3 divides the inner cavity of the crankcase 2 into two cavities 21 connected through the upper vent hole 4 and the lower vent hole 7. The two cavities 21 are respectively opposite to and connected to the two cylinder barrels 11 above. The cylinder body 1 has a cylinder barrel 11 that cooperates with the piston. The piston reciprocates along the axial direction of the cylinder barrel 11 during the stroke movement. The crankcase 2 is located below the cylinder body 1. The vertically arranged support wall 3 in the crankcase 2 can provide support for the crankshaft rotatably connected to the piston connecting rod to stabilize its rotation, and can also provide support for the cylinder body 1 at the same time. The two cylinder barrels 11 can increase the engine displacement and make the engine work more stable. By arranging a lower vent hole 7 and an upper vent hole 4 connecting the two sides of the support wall 3 on the side of the support wall 3 and between the support wall 3 and the cylinder body 1, and making the support wall 3 divide the inner cavity of the crankcase 2 into two cavities 21 and realize mutual communication through the upper vent hole 4 and the lower vent hole 7, and making the cavity 21 face and communicate with the upper cylinder 11 one by one, when the engine is working, the multiple pistons are in different stroke states and positions, and the pistons squeeze the air in the lower cavity 21 to form high pressure when they move downward, and the adjacent pistons will enter the upward state to extract the air in the corresponding cavity 21 to form negative pressure, so that the pressure fluctuation formed by the multiple cylinders 11 is very small, and the air between the positive pressure and negative pressure cavities 21 can be quickly exchanged through the upper vent hole 4 and the lower vent hole 7 to meet the overall pressure balance, thereby reducing the resistance to the piston movement and improving the transmission efficiency. In addition, it also avoids excessive pressure fluctuations in the cavity 21, causing the oil to be atomized and then invade the piston fitting to affect the oil-gas separation effect of the combustion chamber, and also reduces the oil consumption. Furthermore, the engine also includes a gearbox 5, and the inner wall of the crankcase 2 has an air expansion hole 6 connected to the gearbox 5. The engine is also provided with a gearbox 5, which is used to assemble a speed change mechanism. By setting the air expansion hole 6 connected to the gearbox 5 on the inner wall of the crankcase 2, the crankcase 2 is connected to the gearbox 5, so that the volume of the air pressure change caused by the piston movement is increased, that is, the pressure change generated in the crankcase 2 when the piston moves up or down will be better distributed, so that the pressure fluctuation is smaller, further reducing the resistance of the piston movement, ensuring the oil-gas separation effect and improving the engine efficiency. The side edge of the support wall 3 also has a lower vent 7, and the inner wall of the crankcase 2 is perpendicular to the support wall 3 and has an air expansion hole 6 connected to the lower vent 7 at the joint, and the air expansion hole 6 simultaneously connects the cavities 21 on both sides of the support wall 3.By setting the lower vent hole 7 at the side edge of the supporting wall 3, and setting the vent hole 6 at the junction of the inner side wall of the crankcase 2 and the side of the supporting wall 3 to connect and communicate with the lower vent hole 7 at that location, when the air pressure in the cavity 21 changes due to the movement of the piston, the air can be exchanged through the vent hole 6 and the lower vent hole 7 at the same time, and the flow cross-sectional area between the cavity 21 and the gear box 5 and the adjacent cavity 21 is larger, which is conducive to the rapid and applicable exchange of air, and further ensures the pressure balance effect. Preferably, the inner edge of the vent hole 6 and the inner edge of the lower vent hole 7 are both processed with rounded corners. By setting the inner edge of the vent hole 6 and the inner edge of the lower vent hole 7 to be processed with rounded corners, it is ensured that the resistance of air is smaller and smoother when it flows through the vent hole 6 and the lower vent hole 7 here, thereby ensuring pressure balance and improving engine efficiency. There are two vent holes 6 and they are arranged at intervals along the inner side wall of the crankcase 2, and each cavity 21 is connected to the gear box 5 through at least one vent hole 6. By providing a plurality of expansion holes 6 and arranging them at intervals along the inner wall of the crankcase 2, and making each cavity 21 connected to the gearbox 5 through at least one expansion hole 6, it is ensured that the air exchange between each cavity 21 and the gearbox 5 is relatively uniform, which is beneficial to the pressure balance effect.

[0031] like Figure 5 As shown, the crankcase 2 includes an upper case 22 and a lower case 23 that are fixedly connected, and the air expansion hole 6 and the lower air vent 7 are both located at the junction of the upper case 22 and the lower case 23. By setting the crankcase 2 to include an upper case 22 and a lower case 23 that are fixedly connected, the air expansion hole 6 and the lower air vent 7 are both located at the junction of the upper case 22 and the lower case 23, which is conducive to separate processing and grooving, and can reduce the difficulty of the process. In addition, the lower air vent 7 and the air expansion hole 6 are located at the middle position of the height of the crankcase 2, and the balancing effect will not be affected by the engine oil.

[0032] like Figure 2-7 As shown, the top of the support wall 3 has a notch 31, and an upper vent 4 is formed between the notch 31 and the cylinder body 1. By setting the notch 31 at the top of the support wall 3, an upper vent 4 is formed between the notch 31 and the lower end of the cylinder body 1, the notch 31 is more convenient to process, and the upper vent 4 formed between the notch 31 and the cylinder body 1 is closer to the lower end of the cylinder barrel 11. When the piston inhales or squeezes out air, it can more efficiently exchange air with the adjacent cavity 21, reduce excessive impact on the air pressure in the cavity 21, reduce pressure fluctuations, and improve engine efficiency. Further, the lower end of the cylinder barrel 11 protrudes from the lower surface of the cylinder body 1, and the lower end of the cylinder barrel 11 is located in the notch 31 and forms an upper vent 4 between the notch 31 and the notch 31. By arranging the lower end of the cylinder barrel 11 to protrude from the lower surface of the cylinder body 1, and making the lower end of the cylinder barrel 11 located in the notch 31 and forming an upper vent hole 4 between the notch 31, an upper vent hole 4 is further formed between the lower end of the cylinder barrel 11 and the notch 31, thereby ensuring that the upper vent hole 4 directly and efficiently exchanges the air in the cylinder barrel 11.

[0033] The specific embodiments described herein are merely examples of the spirit of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in similar ways, but they will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

Claims

1. A pressure balancing structure of a two-cylinder engine, the engine comprising a cylinder block (1) and a crankcase (2), the cylinder block (1) having two cylinder barrels (11) arranged side by side, the crankcase (2) having a vertically arranged support wall (3), the support wall (3) dividing the inner cavity of the crankcase (2) into two cavities (21), the two cavities (21) respectively facing and communicating with the two cylinder barrels (11) above, It is characterized in that The pressure balancing structure comprises a lower vent hole (7) located on the side of the support wall (3) and / or an upper vent hole (4) located between the support wall (3) and the cylinder body (1), and the upper vent hole (4) and the lower vent hole (7) can both connect the two cavities (21); the engine also comprises a gear box (5), the inner wall of the crankcase (2) has an air expansion hole (6) connected to the gear box (5), the side edge of the support wall (3) has the lower vent hole (7), there are a plurality of air expansion holes (6), at least one air expansion hole (6) is located at the junction of the inner wall of the crankcase (2) and the support wall (3) and is connected to the lower vent hole (7) thereat, the air expansion hole (6) simultaneously connects the cavities (21) on both sides of the support wall (3), and the inner edges of the air expansion hole (6) and the lower vent hole (7) are both subjected to rounded transition treatment.

2. The pressure balance structure of a two-cylinder engine according to claim 1, It is characterized in that The top of the support wall (3) is provided with a notch (31), and the upper vent hole (4) is formed between the notch (31) and the cylinder body (1).

3. The pressure balance structure of the two-cylinder engine according to claim 2, It is characterized in that The lower end of the cylinder barrel (11) protrudes from the lower surface of the cylinder body (1); the lower end of the cylinder barrel (11) is located in the notch (31) and the upper vent hole (4) is formed between the lower end of the cylinder barrel (11) and the notch (31).

4. The pressure balance structure of a two-cylinder engine according to claim 1, It is characterized in that The crankcase (2) comprises an upper case body (22) and a lower case body (23) which are fixedly connected to each other, and the air expansion hole (6) and the lower air vent hole (7) are both located at the junction of the upper case body (22) and the lower case body (23).

5. The pressure balance structure of a two-cylinder engine according to claim 1, It is characterized in that A plurality of the air expansion holes (6) are arranged at intervals along the inner wall of the crankcase (2), and each of the cavities (21) is connected to the gearbox (5) via at least one of the air expansion holes (6).

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