Engine for motorcycle

Abstract

The embodiment of the utility model provides an engine for a motorcycle. The engine comprises a cylinder head cover, a piston and a piston rod, a cylinder head; the valve mechanism comprises a cam shaft, a cam shaft limiting seat cover, an air filter and other parts; a box body; a crankshaft; an oil pump; and an oil pan. The crankshaft and the oil pump are arranged in the box body; the oil pan is arranged at the bottom of the box body; the cylinder cover is arranged on the upper side of the box body; a cam shaft and a cam shaft limiting seat cover in the valve mechanism are arranged in the cylinder cover, and an air filter in the valve mechanism is arranged on the upper side of the cylinder cover; and the cylinder head cover is arranged on the upper side of the cylinder head. Wherein the cylinder head, the camshaft limiting seat cover and the cylinder head cover are jointly provided with a crankcase ventilation structure. According to an engine for a high-compression-ratio motorcycle, more gas in a combustion chamber enters the inner side of a box body through a fit clearance of a cylinder piston due to the problem that the explosion pressure of mixed oil gas in the combustion chamber is too high. A common crankcase ventilation structure is not enough to balance the pressure intensity of gas on the inner side of a crankcase and prevent oil foam of engine oil from being discharged out of the crankcase along with the gas. According to the crankcase ventilation structure, the left side is connected with an air filter through an air pipe, the middle is arranged on a cylinder head cover, and a through hole is formed in the right side and communicates with an inner cavity of a crankcase body through a cam shaft limiting seat cover and a cylinder head. The crankcase ventilation structure is arranged in the mode, the gas flowing distance can be increased, the oil foam blocking structure can be effectively added, the gas flowing direction is changed more repeatedly, the cross sectional area of gas circulation is increased so as to reduce the gas flowing speed, the gas pressure in the crankcase body is balanced, oil foam of engine oil can be effectively prevented from being discharged outwards along with gas, and the engine oil is prevented from being blocked. Therefore, the motorcycle engine with high compression ratio can be adapted.

Description

Technical Field

[0001] The utility model relates to the technical field of motorcycle engines, in particular to a motorcycle engine. Background Art

[0002] Motorcycle engines are usually divided into two categories: straddle bike engines and scooter engines. Motorcycles are widely used in people's daily travel because they are light and flexible, fast and have low energy consumption.

[0003] At present, fossil energy is decreasing day by day, and how to use oil, natural gas, etc. more efficiently has become an inevitable trend in the current social development. In internal combustion engines such as motorcycle engines, increasing the compression ratio of the engine is one of the effective ways to improve fuel utilization. However, in the current related technologies, when the compression ratio of the engine is increased and the mixed oil and gas in the combustion chamber are burned, the gas explosion pressure is too large, and more gas will enter the inner side of the box through the matching gap of the cylinder piston. After the gas enters the inner side of the box, the air pressure inside the box is too high, and the gas inside the box needs to be discharged to the outside. Usually, this part of the gas is discharged into the air filter and enters the combustion chamber again through the air filter. In the limited space of a motorcycle engine, when a crankcase ventilation structure is set to balance the air pressure inside the box, the oil foam of the engine oil usually flows out with the gas. Utility Model Content

[0004] The utility model aims to provide a motorcycle engine, on which a crankcase ventilation structure is arranged to solve the problem in the related art that, in a high compression ratio engine, more gas enters the crankcase, causing excessive gas pressure inside the crankcase and causing oil foam to flow out with the gas.

[0005] In the embodiment of the present application, the crankcase ventilation structure is based on the setting of the oil circulation system of the motorcycle engine, and the crankcase ventilation port needs to be set away from a position where there is a large amount of flowing oil. Therefore, the description of this new use mainly involves the oil circulation setting of the motorcycle engine and the crankcase ventilation structure setting.

[0006] In order to solve the above technical problems, the embodiments of the present invention adopt the following technical solutions:

[0007] An embodiment of the utility model provides a motorcycle engine, the motorcycle engine comprising:

[0008] A box body, wherein a cylinder is provided on the box body;

[0009] A crankshaft, the crankshaft being arranged inside the housing and provided with a coaxial primary drive gear;

[0010] The main shaft is arranged inside the box;

[0011] A clutch, the clutch is connected to the main shaft coaxially by means of a spline to transmit torque;

[0012] The clutch comprises a clutch gear, and the clutch gear is provided with an oil pump driving sprocket coaxial with the central axis;

[0013] An oil pump, the oil pump being arranged inside the box;

[0014] The function of the oil pump is to provide power for the oil circulation of the motorcycle engine so that the mechanical parts of the motorcycle engine can be fully lubricated and cooled.

[0015] An oil pan, which is arranged at the bottom of the box body and mainly functions to store engine oil;

[0016] An oil filter, the oil filter comprising an oil coarse filter and an oil fine filter;

[0017] In the embodiment of the present application, in the motorcycle engine, the crankshaft is the power source of the oil pump. The crankshaft meshes with the clutch gear through the primary drive gear, and transmits torque to the oil pump drive sprocket coaxial with the clutch gear; the oil pump drive sprocket transmits torque to the oil pump drive driven sprocket through the toothed chain, thereby driving the oil pump to work.

[0018] In the motorcycle engine, the engine oil is mainly stored in the oil pan;

[0019] When the oil pump is working, the oil will pass through the oil coarse filter, enter the oil pump through the oil channel at the bottom of the case, and then be discharged from the oil pump into the oil filter. Subsequently, it will flow through various oil channels throughout the engine to achieve the purpose of lubrication and cooling.

[0020] The box body provides a support structure for each mechanism of the engine, and a large number of oil channels are arranged inside, through which the oil cools and lubricates each mechanism. In order to reduce the volume and weight, the structure of the engine is very compact, and the oil for lubricating and cooling each mechanism will be spread all over the inside of the box body in the form of spraying, splashing, etc.

[0021] In some embodiments of the present application, the motorcycle engine further comprises:

[0022] A balancing shaft, wherein the balancing shaft is arranged inside the box;

[0023] The balance shaft is arranged in front of the crankshaft;

[0024] An output countershaft, the output countershaft being arranged in the housing;

[0025] In some embodiments of the present application, the crankshaft, the main shaft and the output secondary shaft are distributed in a triangle;

[0026] The crankshaft and the output secondary shaft are arranged front and back, and the main shaft is arranged above the center line connecting the crankshaft and the output secondary shaft.

[0027] In an embodiment of the present application, the motorcycle engine further comprises:

[0028] A cylinder head, the cylinder head being arranged on the upper side of the box body;

[0029] Valve mechanism;

[0030] Wherein, the valve mechanism includes a camshaft, a camshaft limit seat cover, an air filter and other parts;

[0031] In an embodiment of the present application, the camshaft limit seat cover in the valve mechanism is arranged in the cylinder head, and the air filter in the valve mechanism is arranged on the upper side of the cylinder head cover;

[0032] A cylinder head cover, the cylinder head cover is arranged on the upper side of the cylinder head;

[0033] An air filter, the air filter being arranged on the upper side of the cylinder head cover;

[0034] A throttle body is disposed between the upper rear side of the cylinder head and the lower rear side of the air filter, and the throttle body is connected to the air filter and the cylinder head;

[0035] In the embodiment of the utility model application, the upper side of the box body is connected to the cylinder head, the upper side of the cylinder head is connected to the camshaft limit seat cover, the upper side of the camshaft limit seat cover is connected to the cylinder head cover, and a vent pipe joint is provided on the right side of the cylinder head cover, and the vent pipe joint is connected to the air filter through a rubber tube;

[0036] In the embodiment of the present application, the right side vent pipe joint of the cylinder head cover is interference fit on the cylinder head cover, and the extended side is connected to the rubber tube;

[0037] In the embodiment of the present application, an O-type sealing rubber ring is provided at the connection between the camshaft limit seat cover and the cylinder head cover;

[0038] In an embodiment of the present application, a right oil return hole is provided at the right front of the cylinder head cover, and the lower part of the right oil return hole is connected to the camshaft through a hollow pin, wherein a rubber sealing ring is provided at the hollow pin;

[0039] In an embodiment of the present application, a left oil return hole is provided on the left side of the cylinder head cover, and the left oil return hole extends to the cylinder head chamber.

[0040] In an embodiment of the present application, a cylinder head cover top cover is also provided on the upper side of the cylinder head cover;

[0041] In the embodiment of the present application, the cylinder head cover top cover and the cylinder head cover together form a partial chamber of the crankcase ventilation structure, a rubber sealing ring is provided between the two, and multiple baffles are provided inside the chamber to change the gas flow direction and block the oil foam;

[0042] In the embodiment of the present application, the chamber inside the housing can pass through the cylinder head chamber, the camshaft limit seat cover chamber, and then the cylinder head cover and the vent pipe, and communicate with the air filter to form a crankcase ventilation structure. Compared with the general crankcase ventilation structure, the crankcase ventilation structure is set in the above manner, which can greatly increase the gas flow distance, more effectively increase the oil foam blocking structure, change the gas flow direction more times, and increase the cross-sectional area of ​​gas flow to reduce the gas flow rate, so as to achieve both balancing the gas pressure inside the housing and more effectively preventing the oil foam of the engine oil from being discharged with the gas, so as to adapt to the motorcycle engine with a high compression ratio. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the embodiments of the utility model application and the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the embodiments and the prior art description. Obviously, the drawings in the following description are only for the present embodiment. For ordinary technicians in this field, other drawings can also be obtained based on the drawings provided in this application without creative work.

[0044] Figure 1 This is a schematic diagram of the distribution of various shaft systems inside a motorcycle engine provided by an embodiment of the utility model;

[0045] Figure 2 yes Figure 1 AA cross-sectional diagram of ;

[0046] Figure 3 This is a schematic diagram of a box structure of a motorcycle engine provided by an embodiment of the utility model;

[0047] Figure 4 This is a schematic diagram of the upper box structure of a motorcycle engine provided by an embodiment of the utility model;

[0048] Figure 5 This is a schematic diagram of a main shaft of a motorcycle engine provided by an embodiment of the utility model;

[0049] Figure 6 and Figure 7 This is a schematic diagram of a clutch structure of a motorcycle engine provided by an embodiment of the utility model;

[0050] Figure 8 It is a schematic diagram of the structure of a cylinder head cover of a motorcycle engine provided by an embodiment of the utility model;

[0051] Fig. 9 yes Figure 8 BB cross-sectional diagram;

[0052] Fig.10 It is a schematic diagram of a valve train for a motorcycle engine provided by an embodiment of the utility model;

[0053] Fig.11 yes Fig.10 Schematic diagram of CC cross section;

[0054] Fig.12 The utility model is a schematic diagram of a crank-connecting rod mechanism of a motorcycle engine provided by an embodiment of the utility model.

[0055] Reference numerals: 100, cylinder head cover; 101, right oil return channel; 102, left oil return channel; 103, oil return groove; 104, vent pipe joint; 105, cylinder head cover top cover; 106, sealing rubber ring; 107, O-type sealing rubber ring; 108, sealing rubber ring; 200, cylinder head; 201, camshaft limit seat cover; 202, camshaft; 203, rotating nut; 204, rectangular key; 205, copper gasket; 206, bolt; 207, sliding tappet; 208, rocker arm; 209, rocker arm shaft; 210, valve clearance; 300, housing; 301, upper housing; 302, lower housing; 303, accommodating groove; 304, connecting part; 305, cylinder block; 306, main shaft mounting hole; 307, connecting piece; 400, crank-connecting rod mechanism; 401, crankshaft; 402, balance shaft; 403, primary drive gear; 404, balance shaft gear; 405, piston; 500, tensioning mechanism; 600, speed change mechanism; 601, main shaft; 602, secondary shaft; 700, clutch; 701, clutch gear; 702, oil pump drive active sprocket; 703, clutch bushing; 704 clutch needle bearing; 900, oil pump; 901, oil pump drive driven sprocket; 902, oil pump chain; 903, oil fine filter; 1300, left crankcase cover; 1400, oil pan. DETAILED DESCRIPTION

[0056] The following content will be combined with the drawings in the embodiments of the present application to provide a detailed and comprehensive description of the technical solutions in the embodiments of the present application. It should be noted that the described embodiment is only one embodiment of the present application, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the protection scope of the present application.

[0057] In the description of the embodiments of the utility model application, it should be noted that the orientation or position relationship indicated by the terms "upper", "lower", "left", "right", "front", "back", "inside", "outside", "center", "horizontal", "vertical", etc. is based on the orientation or position relationship shown in the accompanying drawings, and is only for the convenience of simplifying the description of the embodiments of the present application, rather than indicating or implying that the device or element referred to must have a specific orientation, and a specific orientation structure and operation, and therefore cannot be understood as a limitation on the embodiments of the present application. In addition, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. In the description of the present application, the meaning of multiple is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0058] In the description of the embodiments of the present utility model application, unless otherwise clearly specified or limited, the terms "installed", "connected" and "connected" should be understood in a broad sense. The first feature may be directly connected to the second feature, or they may be indirectly connected through an intermediate medium. In the present application, unless otherwise clearly specified or limited, the first feature being "above" or "below" the second feature may mean that the first feature and the second feature are in direct contact, or they may be in indirect contact through an intermediate medium. Furthermore, the first feature being "on the upper side" of the second feature may mean that the first feature is directly above or obliquely above the second feature, or it may simply mean that the first feature is at a higher level than the second feature. The first feature being "on the lower side" of the second feature may mean that the first feature is directly below or obliquely below the second feature, or it may simply mean that the first feature is at a lower level than the second feature.

[0059] The terms "and", "or", and "and" used in the specification of this application include any and all combinations of one or more related listed items. Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as those commonly understood by technicians in the technical field of this application. The terms used in the description of this application are only for describing specific implementation methods and are not intended to limit this application.

[0060] The embodiment described in the present application provides an engine 369, which is mainly used in motorcycles. If a transmission system and a vehicle body are matched, the possibility of using the engine in other vehicle models is not excluded. If distinguished by functional system, the engine 369 is mainly composed of a body group 300, a valve mechanism, a transmission system, a fuel supply system, an ignition system, a cooling system, a lubrication system, a starting system, etc.; if distinguished by structure, the engine 369 is mainly composed of a cylinder head cover 100, a cylinder head cover 200, a box body 300, a crank connecting rod mechanism 400, a tensioning mechanism 500, a speed change mechanism 600, a clutch 700, an oil pump 900, a left crankcase cover 1300, an oil pan 1400, etc.

[0061] like Figure 1 and Figure 2 As shown, the transmission system includes a crank-connecting rod mechanism 400, which includes a crankshaft 401 and a balance shaft 402. The crankshaft is provided with a primary drive gear 403, and the balance shaft is provided with a balance shaft gear 404. The crankshaft 401 transmits torque to the balance shaft through the meshing transmission of the primary drive gear 403 and the balance shaft gear 404. The crankshaft 401 converts the explosion pressure of the mixed oil and gas combustion into the rotational torque of the crankshaft 401, thereby outputting power.

[0062] like Figure 1 and Figure 2 As shown, the transmission system further includes a speed change mechanism 600, which includes a main shaft 601 and a secondary shaft 602, wherein a plurality of groups of speed change driving gears are arranged on the main shaft 601, and a plurality of groups of speed change driven gears are arranged on the secondary shaft 602. The transmission system further includes a clutch 700, which includes a clutch gear 701, an oil pump driving sprocket 702, a clutch bushing 703, and a needle bearing 704.

[0063] like Figure 1 and Figure 2 As shown, the crankshaft 401 is arranged between the balance shaft 402 and the main shaft 601, the secondary shaft 602 is arranged on the other side of the main shaft 601 away from the crankshaft 401, and the clutch gear 701 is arranged at the end of the main shaft 601 and meshes with the primary drive gear 403. In the figure, the axis of the main shaft and the axis of the crankshaft determine the first plane, and the axis of the main shaft and the axis of the secondary shaft determine the second plane, and an angle θ is formed between the first plane and the second plane. In the embodiment, θ≈94°. The crankshaft, the main shaft and the secondary shaft are arranged in this way, and the angle θ is selected to have this angle value, so that the main shaft is staggered with the crankshaft and the secondary shaft, respectively, thereby reducing the space required for the engine and reserving more space for the installation of other parts.

[0064] In other embodiments, the angle θ may also be selected to have other values ​​according to design requirements.

[0065] like Figure 1As shown, the axis of the crankshaft 401 and the axis of the secondary shaft 602 determine the third plane, and the angle between the first plane and the third plane is α. In the embodiment, α≈25°. The crankshaft, the main shaft and the secondary shaft are arranged in this way, and the angle α is selected to achieve the purpose of both normally transmitting the rotational torque of the transmission system and reducing the space required for the engine, thereby achieving lightweight.

[0066] In other embodiments, the angle α may also be selected to have other values ​​according to design requirements.

[0067] like Figure 1 and Figure 2 , Figure 6 As shown, in the engine, the primary drive gear 403 on the crankshaft 401 is meshed with the clutch gear 701 to transmit the rotational torque to the clutch 700; the clutch 700 then drives the main shaft 601 to rotate; the main shaft 601 and the secondary shaft 602 are meshed with each gear gear, and finally the power is output outwardly from the secondary shaft.

[0068] In addition, the clutch gear 701 and the oil pump driving sprocket 702 are an integrated structure with the same rotation speed. The oil pump driving sprocket 702 is connected to the oil pump driving driven sprocket 901 through the oil pump chain 902, and transmits the rotational torque to the oil pump 900, thereby driving the oil pump 900 to supply oil to the various mechanisms of the engine for lubrication and cooling.

[0069] Continue reading Figure 1 and Figure 2 , Figure 3 The oil pan 1400 is arranged at the lower side of the lower box 302, and its main function is to collect the oil refluxed from the engine 369 and store the oil of the engine 369. An oil coarse filter is arranged inside the oil pan, which can filter out the larger particle impurities in the oil and prevent the impurities from entering the oil pump 900 through the oil channel of the lower box, thereby achieving the purpose of protecting the oil pump. After the oil is pressurized by the oil pump 900, it continues to pass through the oil channel inside the lower box 302 and enters the fine filter. The fine filter is provided with a filter element inside, which can block and filter out the tiny particle impurities in the oil, so that the clean oil can pass through and enter the subsequent oil channel.

[0070] Furthermore, after passing through the oil channel of the lower housing 302, part of the engine oil enters the journal of the crankshaft 401 to lubricate and cool the journal and the bearing. Here, part of the engine oil flows out from the gap between the journal and the bearing and returns to the oil pan 1400; the remaining part of the engine oil passes through the oil channel provided on the crank of the crankshaft 401, enters the crank and the big end of the connecting rod, and is also lubricated and cooled. Thereafter, it flows back to the oil pan 1400 through the gap between the crank, the big end of the connecting rod and the bearing; part of the engine oil passes through the oil pins corresponding to each cylinder provided in the lower housing, and is sprayed onto the inner wall of the cylinder body 305 and the bottom of the piston 405 for lubrication and cooling, and then flows back to the oil pan 1400.

[0071] Furthermore, after passing through the oil channel of the lower housing 302, part of the oil enters the right journal of the balance shaft 402. In order to reduce weight, the balance shaft is hollow inside, and oil holes are provided on the journals at both ends that are mounted with the bearings. Therefore, the oil can lubricate and cool the journals and bearings on both sides of the balance shaft, and then flow back to the oil pan 1400.

[0072] Furthermore, part of the oil passes through the oil channel of the lower housing 302 and enters the main shaft 601. The main shaft is also hollow inside, and oil holes are provided at positions corresponding to the multiple groups of speed-changing driving gears on the main shaft. Therefore, the oil can pass through each oil hole to lubricate and cool each group of speed-changing driving gears, and then flow back to the oil pan. Another part of the oil enters the clutch through the main shaft oil hole to lubricate and cool the clutch, and then returns to the oil pan 1400.

[0073] Furthermore, part of the oil passes through the oil channel of the lower housing 302 and enters the secondary shaft 602. The interior of the secondary shaft is also a hollow structure, and oil holes are provided at positions corresponding to multiple groups of speed-changing driven gears on the secondary shaft. Therefore, the oil can lubricate and cool each group of speed-changing driven gears through each oil hole, and then flow back to the oil pan 1400.

[0074] Furthermore, after some of the oil passes through the oil channel of the lower case 302, it continues to pass through the oil channel of the upper case 301 and enters the oil channel of the cylinder head engine 200. At the same time, an oil channel is provided on the right side where the cylinder head and the camshaft 202 are installed and matched, and the oil can enter the camshaft through the oil hole on the camshaft. The interior of the camshaft 202 is also a hollow structure, and oil holes are provided on the base circle of each cam of the camshaft and on each journal installed in conjunction with the cylinder head. Therefore, the oil can lubricate and cool the camshaft and matching parts through each oil hole, and then flow back to the oil pan 1400.

[0075] In the motorcycle engine described in the utility model, due to the operation of various components, it is inevitable that there will be oil or oil splashes at various positions inside the engine.

[0076] like Fig.10 , Fig.11 , Fig.12 As shown, the motorcycle engine described in the utility model has a relatively high compression ratio and is a four-stroke engine, and the four strokes are intake, compression, power, and exhaust. During the intake stroke, the camshaft 202 pushes the sliding tappet 207, the intake valve opens, the exhaust valve closes, the piston moves downward, and the cylinder sucks a mixed oil and gas with an appropriate air-fuel ratio; during the compression stroke, the intake and exhaust valves are closed, the piston moves upward, and the mixed oil and gas are compressed to a high-pressure state; during the power stroke, the intake and exhaust valves are closed, the mixed oil and gas are ignited by the spark plug and burn violently, and the high pressure acts on the top of the piston, pushing the piston downward rapidly; during the exhaust stroke, the camshaft pushes the rocker arm 208, the intake valve closes, the exhaust valve opens, the piston moves upward, and the burned gas is discharged to the outside through the exhaust valve and the exhaust pipe.

[0077] In the early and middle stages of the power stroke, the gas pressure in the combustion chamber formed by the top of the piston 405 and the bottom of the cylinder head 200 is extremely high. At this time, since the cylinder body 305 and the piston 405 cannot be completely sealed, it is inevitable that some gas will pass through the gap between the cylinder body 305 and the piston 405 and enter the interior of the box body 300.

[0078] In summary, a crankcase ventilation structure must be provided to satisfy the requirements of exhausting the gas inside the crankcase 300 and balancing the air pressure, and to prevent the oil foam from being discharged outward along with the gas.

[0079] The density of oil foam is greater than that of gas, and the inertia of the same volume of oil foam is greater than that of gas. Therefore, when the gas and oil foam with the same speed change their flow direction at the same time, it is more difficult for the oil foam to turn and it is easy to collide with the inner wall of the chamber. When the oil foam collides with the inner wall of the chamber, it will flow back to the oil pan along the inner wall of the chamber due to the effect of gravity.

[0080] like Figure 1 , Figure 8 , Fig. 9 As shown, the housing 300, the cylinder head 200, and the cylinder head cover 100 of the motorcycle engine of the utility model are provided with chambers which are interconnected. As shown in the figure, there are multiple turns in the interconnected chambers, and when the gas flows from the inside of the housing 300 to the vent pipe on the right side of the cylinder head cover 100, the gas flow direction changes multiple times.

[0081] like Fig. 9 As shown, the cylinder head 200 is arranged on the upper side of the box body 300, and the right chamber of the cylinder head is connected to the right chamber of the box body. The space at this position is relatively large, which can be used for the oil on the cylinder head to flow back through it, and for the gas inside the box to be discharged upward through it.

[0082] like Fig. 9As shown, the camshaft limit seat cover 201 is arranged on the upper right side of the cylinder head 200, and a chamber is arranged in the camshaft limit seat cover, and the camshaft limit seat cover chamber is connected with the cylinder head chamber. Here, the camshaft limit seat cover chamber can allow the gas inside the box to be discharged upward, and at the same time, the gas flow direction is changed to block part of the oil foam.

[0083] like Figure 8 , Fig. 9 As shown, the cylinder head cover 100 is arranged on the upper side of the cylinder head, and a through hole is arranged on the right side of the cylinder head cover, which is connected to the camshaft limit seat cover 201. The through hole on the right side of the cylinder head cover and the subsequent chamber can allow the gas inside the box to be discharged to the left, and the gas flow direction changes multiple times, blocking part of the oil foam. The cylinder head cover 100 has the longest chamber stroke and the most number of gas flow direction changes, so it has the best effect in blocking the oil foam. It is necessary to set an appropriate channel so that the blocked oil foam can flow back to the oil pan.

[0084] like Figure 8 , Fig. 9 As shown, the right front side of the cylinder head cover is provided with a right oil return channel 101, the left side is provided with a left oil return channel 102, and the frontmost side of the middle chamber is provided with an oil return groove 103. The right oil return channel 101 is connected to the camshaft limit seat cover 201 through a hollow positioning pin at the lower side, and continues to connect to the cylinder head chamber after passing through the camshaft limit seat cover 201. A sealing rubber ring is provided on the outside of the hollow positioning pin to prevent external engine oil from entering the right oil return channel through the connection. The left oil return channel 102 is provided with a longer oil return channel to reach the lower chamber of the cylinder head.

[0085] When the engine of the utility model is in the complete vehicle state, the front side of the cylinder head cover is lower than the rear side. Therefore, the right oil return channel 101 and the left oil return channel 102 are both arranged at the lowest position on the left and right sides, so as to ensure that no matter the vehicle is in the riding state or the static state, the oil return channel is at the lowest position, so that the oil foam inside the cylinder head cover chamber flows back to the oil pan.

[0086] like Fig. 9 As shown, an O-type sealing rubber ring is provided at the connection between the cylinder head cover 100 and the camshaft limit seat cover 201 to prevent external engine oil from entering the cylinder head cover chamber through the connection.

[0087] like Fig. 9 As shown, the cylinder head cover top cover 105 is arranged on the upper side of the cylinder head cover 100, and a sealing rubber ring 106 is provided at the connection.

[0088] like Fig. 9 As shown, the vent pipe joint 104 is arranged on the left side of the cylinder head cover, and the vent pipe joint is press-fitted on the cylinder head cover. The vent pipe joint 104 is interconnected with a rubber tube, and the other side of the rubber tube is connected to an air filter.

[0089] In the embodiment described in the present application, the gas inside the engine case enters the combustion chamber again after passing through the cylinder head, camshaft stopper cover, cylinder head cover, vent pipe, air filter and other components, and is discharged from the exhaust valve and exhaust pipe after combustion. This means that all the starting gas discharged to the outside has undergone high temperature and high pressure reactions, which prevents a large amount of combustibles such as oil foam, hydrocarbons, carbon monoxide, etc. from being directly discharged into the air.

[0090] In summary, the valve mechanism controls the opening and closing of the intake and exhaust valves through the camshaft 202, the sliding tappet 207, the rocker arm 208 and other components, so as to cooperate with the operation of the four-stroke engine. In the early and middle stages of the power stroke of the high-compression ratio engine, due to the intense combustion inside the combustion chamber to generate high pressure, it is inevitable that some gas will enter the box through the cylinder-piston gap. In order to stabilize the gas pressure inside the box 300, this part of the gas needs to be discharged from the box. The crankcase ventilation structure involves multiple components such as the box 300, the cylinder head 200, the camshaft limit seat cover 201, and the cylinder head cover 100. The general crankcase ventilation structure is usually only arranged at the corners of the box, the structure is short and narrow, and it needs to occupy additional space in the box. While discharging gas to the outside, it cannot effectively prevent the oil foam from being discharged to the outside, and cannot meet the needs of high-compression ratio engines. Compared with the general crankcase ventilation structure, the crankcase ventilation structure is arranged in the manner described, without occupying additional space in the engine case, and at the same time can greatly increase the gas flow distance, more effectively increase the oil foam blocking structure, and change the gas flow direction more times, so as to increase the cross-sectional area of ​​gas flow to reduce the gas flow rate, thereby achieving both balancing the gas pressure inside the case and more effectively preventing the oil foam of the engine oil from being discharged outward with the gas, thereby meeting the needs of high compression ratio engines.

[0091] The crankcase ventilation structure embodiment described above is used to illustrate the technical solution of the utility model, and its description is relatively specific and detailed, but it is not intended to limit it; for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the structural arrangement of the present application, and these modifications and improvements belong to the protection scope of the utility model. The patent protection scope of the utility model shall be subject to the attached claims.

Claims

1. A motorcycle engine, It is characterized in that The motorcycle engine comprises: a cylinder head cover; a cylinder head; a valve mechanism, wherein the valve mechanism comprises a camshaft, a camshaft limit seat cover, an air filter and other parts; a housing; a crankshaft; an oil pump; and an oil pan. The crankshaft, clutch, speed change mechanism and oil pump are installed in the box; The oil pan is arranged at the bottom of the box body; The cylinder head is arranged on the upper side of the box body; The camshaft in the valve mechanism, the camshaft limit seat cover is arranged on the upper side of the cylinder head, and the air filter in the valve mechanism is arranged on the upper side of the cylinder head cover; The cylinder head cover is arranged on the upper side of the cylinder head; 2. The engine according to claim 1, It is characterized in that The upper side of the cylinder head is connected to the camshaft limit seat cover, the upper side of the camshaft limit seat cover is connected to the cylinder head cover, a vent pipe joint is provided on the right side of the cylinder head cover, and the vent pipe joint is connected to the air filter through a rubber tube; 3. The engine according to claim 1, It is characterized in that The right side vent pipe joint of the cylinder head cover is press-fitted on the cylinder head cover, and the extended side is connected to the rubber tube; 4. The engine according to claim 2, It is characterized in that The chamber inside the housing can pass through the cylinder head chamber, the camshaft limit seat cover chamber, the cylinder head cover and the vent pipe, and communicate with the air filter; 5. The engine according to claim 2, It is characterized in that An O-type sealing rubber ring is provided at the connection between the camshaft limit seat cover and the cylinder head cover; A right oil return hole is provided at the right front of the cylinder head cover, and the lower part of the right oil return hole is connected to the camshaft through a hollow pin, wherein a rubber sealing ring is provided at the hollow pin; A left oil return hole is provided on the left side of the cylinder head cover, and the left oil return hole extends to the cylinder head chamber.

6. The engine according to claim 2, It is characterized in that A cylinder head cover top cover is also provided on the upper side of the cylinder head cover; The cylinder head cover top cover and the cylinder head cover together form a partial chamber of the crankcase ventilation structure, a rubber sealing ring is arranged between the two, and multiple baffles are arranged inside the chamber to change the gas flow direction and block the oil foam; 7. The engine according to claim 1, It is characterized in that The engine also includes a throttle body; The throttle body is arranged between the rear upper side of the cylinder head and the rear lower side of the air filter, and the throttle body is connected with the air filter and the cylinder head; 8. The engine according to claim 1, It is characterized in that The box body also includes a cylinder body, and the crankshaft is connected to the piston through a crank-connecting rod mechanism; The piston is disposed in the cylinder body, and the top of the piston and the bottom of the cylinder head together form a combustion chamber; 9. The engine according to claim 1, It is characterized in that The engine further comprises an oil coarse filter and an oil fine filter, wherein the oil coarse filter is arranged at the lower side of the casing and extends to the bottom of the oil pan, and the oil fine filter is arranged at the lower front side of the casing; The oil path of the engine passes through the oil coarse filter, the oil fine filter and the oil passage of the box body, and leads to various mechanisms that need lubrication and cooling; 10. The engine according to claim 1, It is characterized in that The compression ratio is higher than that of ordinary motorcycle engines, the fuel utilization rate is higher, and the explosion pressure inside the combustion chamber is greater. Therefore, more gas will enter the inside of the box through the gap between the cylinder piston when the explosion pressure is generated.

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