Horizontal double-cylinder engine of motorcycle

Abstract

The horizontal double-cylinder engine comprises an engine body, two air cylinders, two pistons, a crank connecting rod mechanism and an air distribution mechanism, each air cylinder is provided with a plurality of air inlet mechanisms and exhaust mechanisms in a matched mode, and the air distribution mechanism comprises an air inlet cam shaft, an exhaust cam shaft, an air inlet timing chain wheel and an exhaust timing chain wheel; the crank connecting rod mechanism comprises a left crank, a right crank and a crank pin, two piston connecting rods are arranged in the middle of the crank pin in a sleeved mode, a timing driving chain wheel is connected to the left crank in a sleeved mode, and the timing driving chain wheel, the air inlet timing chain wheel and the exhaust timing chain wheel are located on the same side and connected through a timing chain. A CVT driving belt wheel is connected to the right crank in a sleeved mode, the CVT driving belt wheel is in transmission connection with a CVT driven belt wheel on one side of the CVT driving belt wheel through a belt, the CVT driven belt wheel is fixedly connected to a main transmission shaft in a sleeved mode, an input gear is connected to the main transmission shaft in a sleeved mode, and an output gear in transmission connection with the input gear is arranged on one side of the input gear.

Description

Technical Field

[0001] The invention relates to the field of motorcycle engines, and in particular to a horizontal twin-cylinder engine for a motorcycle. Background Art

[0002] The engine of a motorcycle is one of the core components of a motorcycle, responsible for providing power to make the vehicle run. At present, motorcycle engines are mainly divided into single-cylinder engines and multi-cylinder engines. Among them, multi-cylinder engines are more complex in structure, have greater power output, and are smoother in power output than single-cylinder engines. Multi-cylinder engines include but are not limited to twin-cylinder, three-cylinder, four-cylinder, etc. These engines increase power output and stability by increasing the number of cylinders. Common multi-cylinder engine arrangements include: parallel (in-line) engines, V-type engines, horizontally opposed engines, and W-type engines. The cylinders of a parallel engine are arranged vertically on a plane, such as an in-line twin-cylinder or in-line four-cylinder (in-line four-cylinder) engine.

[0003] The existing in-line twin-cylinder engines are mostly vertical, occupying a large space in the vertical direction, and the overall structure is also relatively complex. At the same time, the existing twin-cylinder engines place the sprocket in the middle, which causes large vibrations during operation. Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, an object of the present invention is to provide a horizontal twin-cylinder engine for a motorcycle, so as to solve the problems of the existing twin-cylinder engines for motorcycles having a complex structure and large vibrations during operation.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions: A horizontal twin-cylinder engine for a motorcycle, comprising a body, two cylinders, two pistons, a fuel injection device, an ignition device, a crank-connecting rod mechanism and a valve mechanism, each set of cylinders is equipped with a plurality of intake mechanisms and exhaust mechanisms, the valve mechanism comprises an intake camshaft and an exhaust camshaft, an intake timing sprocket and an exhaust timing sprocket are respectively sleeved at the same side end positions of the intake camshaft and the exhaust camshaft; the crank-connecting rod mechanism comprises a left crank, a right crank and a crank pin installed between the left crank and the right crank, two piston connecting rods are sleeved at the middle of the crank pin, a timing driving sprocket is sleeved on the left crank, the timing driving sprocket is sleeved with the intake timing sprocket The right crank is located on the same side as the exhaust timing sprocket and is connected by a timing chain. A balance shaft driving gear and a CVT driving pulley are sleeved on the right crank from the inside to the outside in sequence. A CVT driven pulley is provided on one side of the CVT driving pulley. The CVT driving pulley and the CVT driven pulley are connected by a belt transmission. The CVT driven pulley is sleeved and fixed on a main transmission shaft. An input gear is sleeved and fixed on the main transmission shaft. An output gear connected to the input gear is provided on one side of the input gear. A balance shaft parallel to the right crank is provided on one side. A balance shaft driven gear meshing with the balance shaft driving gear is sleeved on the balance shaft. In this way, the valve mechanism, the intake mechanism and the exhaust mechanism are all located at the front end of the engine, the crank-connecting rod structure is located at the rear end of the engine body, and the transmission mechanism is distributed horizontally as a whole, that is, a horizontal two-cylinder engine is formed. Compared with a vertical two-cylinder engine, this arrangement has a smaller longitudinal assembly height. At the same time, the right crank is used to drive the CVT driving pulley to rotate, and the overall layout is compact. The intake timing sprocket and exhaust timing sprocket are respectively located at the end positions of the intake camshaft and the exhaust camshaft, which changes the installation position of the timing driven sprocket of the traditional two-cylinder engine. The end position is close to the assembly end of the shaft, and relatively speaking, the vibration is smaller. When the crank-connecting rod mechanism rotates after the piston is ignited, it will drive the CVT driving pulley, CVT driven pulley and main drive shaft sleeved thereon, and finally output the power to the output gear through the input gear to achieve power output. When the right crank rotates, the balance shaft driving gear will drive the balance shaft driven gear meshing with it to rotate, and then the balance shaft will rotate. After the balance shaft rotates, it can reduce the vibration of the engine.

[0006] Furthermore, the engine body includes a cylinder head cover, a cylinder head, a cylinder body, a crankcase, a left cover, a right cover and a CVT cover. The cylinder head cover, the cylinder head and the cylinder body are connected front and back in sequence. The crankcase includes a left crankcase and a right crankcase. The outer side of the left crankcase is sealed and connected to the left cover, the right crankcase is sealed and connected to the right cover, and the CVT cover is connected to the outer side of the right cover and together form a CVT case body; multiple heat sinks are provided on the outer end surfaces of the cylinder head cover, the cylinder head and the cylinder body. In this way, the crankcase and the CVT case body are separated in the engine body. The heat generated by the CVT case body is higher than that of the crankcase. After separating the two, the hot air of the CVT case body can be prevented from flowing into the crankcase, which affects the service life of the transmission parts in the crankcase. The cylinder head cover, the cylinder head and the cylinder body are connected to the combustion chamber. After multiple heat sinks are provided circumferentially on the outer end surfaces of the above components, the heat generated by the above components can be taken away by air cooling.

[0007] Furthermore, an air inlet and an air outlet connected to the CVT housing are provided on the upper side of the right cover, the air inlet is provided close to the CVT driving pulley, and the air outlet is provided close to the CVT driven pulley; an air inlet chamber connected to the air inlet is provided on the CVT cover, and an air outlet corresponding to the blades of the CVT driving pulley is provided on the side of the air inlet chamber facing the right cover. In this way, after the air inlet and the air outlet are provided on the right cover, both the air inlet and the air outlet are provided on the upper side of the right cover, and the mold opening is correspondingly simpler, which can effectively reduce the mold opening cost. When the exhaust duct is provided upward, stones can be prevented from being thrown into the CVT housing. After the motorcycle engine is started, the CVT driving pulley rotates, causing the blades on the driving pulley to rotate as well, forming a negative pressure outside the box, sucking the cold air outside the box from the air inlet duct to the air inlet chamber, and then passing through the air outlet to the driving pulley to cool the driving pulley. At the same time, under the action of the driving pulley blades, the air flows to the driven pulley, passes through the driven pulley, and is guided to the air outlet duct along its side wall in a clockwise direction, and the hot air is discharged from the air outlet duct. Since the air outlet is set forward, when the hot air is discharged from the exhaust channel, the external cold air will directly blow the hot air in the opposite direction of riding, and will not flow to the front end, and the hot air flow can be taken away at the first time. The set air inlet chamber can form a vortex in the air inlet chamber after sucking the external cold air, thereby increasing the air flow rate.

[0008] Furthermore, a barrier rib is provided on the side of the right cover facing the CVT cover, the upper end of the barrier rib is connected to the upper wall of the right cover, and the lower end extends in the direction of the CVT driven pulley axis; the barrier rib is arranged obliquely, and the oblique direction is consistent with the air outlet. In this way, the barrier rib can form a certain barrier to the air on the driven wheel side, preventing the hot air from being discharged from the air outlet, and part of the hot air enters the driving wheel through the space at the upper end of the driven wheel, affecting the hot air discharge efficiency.

[0009] Furthermore, it also includes an oil lubrication system, which includes an oil collecting chamber arranged at the bottom of the crankcase body and a coarse filter, an oil pump, an external oil cooler, a fine filter and a main oil circuit which are connected in sequence, one end of the coarse filter is immersed in the lubricating oil in the oil collecting chamber, the oil pump is assembled in the crankcase body, the oil cooler is placed on a motorcycle frame outside the crankcase body, and is provided with an oil inlet pipeline and an oil outlet pipeline; the fine filter and the coarse filter are both arranged on the lower end surface of the crankcase body, the coarse filter is connected to the oil inlet pipe of the oil pump through a first oil guide channel arranged in the crankcase body, the oil outlet of the first oil guide channel is connected to the oil inlet pipeline of the oil cooler, and the oil outlet pipeline of the oil cooler is connected to the fine filter through a second oil guide channel arranged on the crankcase body; the inner end of the fine filter is placed in the crankcase body, and the end is connected to the main oil channel in the crankcase body. In this way, on the basis of providing heat sinks and air inlet and outlet ducts for air cooling and heat dissipation, the oil lubrication system provided can realize oil cooling for the crankshaft, crankcase, cylinder block and cylinder head. After long-term circulation and use, the lubricating oil in the oil collecting chamber will produce some impurities. At the same time, after oil cooling and lubrication of various components, the temperature of the lubricating oil will rise after falling back into the oil collecting chamber, thereby affecting subsequent lubrication and cooling. After the high-temperature lubricating oil in the oil collecting chamber is initially filtered by the coarse filter, it is pumped to the oil cooler outside the crankcase body by the oil pump, and after cooling treatment by the oil cooler, it is guided from the oil outlet pipeline of the oil cooler to the second oil guide channel of the crankcase body, and finally enters the fine filter, and is further finely filtered by the fine filter. Finally, the cooled and filtered lubricating oil is transported to various oil circuits through the main oil channel on the crankcase body to lubricate various transmission components in the crankcase body. The coarse filter and fine filter provided are installed on the lower end surface of the crankcase body and are located on the same side. It is convenient to install and disassemble, and there is no need to stand on both sides for installation or disassembly. The oil cooler is arranged outside the crankcase body and on the motorcycle frame, does not occupy the space of the engine, and can effectively reduce the volume of the engine.

[0010] Furthermore, the installation height of the coarse filter is lower than that of the fine filter, and the oil lubrication system also includes a main transmission shaft lubrication oil passage, a crankshaft lubrication oil passage, a box oil outlet passage, two piston lubrication oil passages, a cylinder cooling oil passage, and a cylinder head cooling oil passage, which are connected to the main oil passage. In this way, after the coarse filter is set to a lower installation position, the path between the oil collecting chamber and the coarse filter can be shortened. After the lubricating oil is cooled and finely filtered, the cooled lubricating oil can be pumped to the main transmission shaft, crankshaft, crankcase, piston, cylinder body, and cylinder head through the main oil passage to cool and lubricate various components in the engine that are at high temperatures.

[0011] Furthermore, the crankcase is formed by connecting a left crankcase and a right crankcase; two piston oil spray nozzles are arranged in the crankcase towards the back of the piston, and a left lubricating oil passage and a right lubricating oil passage are respectively arranged on the interface between the left crankcase and the right crankcase and the cylinder body, one end of the right lubricating oil passage is connected with the oil outlet passage of the case, and the two piston lubricating oil passages are respectively arranged in the left crankcase and the right crankcase, and are connected with the left lubricating oil passage and the right lubricating oil passage on the corresponding side; a matching oil passage for connecting the left lubricating oil passage and the right lubricating oil passage is provided on the case interface of the cylinder body, and the left and right sides of the matching oil passage are respectively matched with the left lubricating oil passage and the right lubricating oil passage. In this way, when the oil pump pumps the lubricating oil from the crankcase to the cylinder body, the lubricating oil passes through the case outlet passage of the crankcase, and then enters the right lubricating oil passage, the matching oil passage and the left lubricating oil passage in turn, and then is guided to the piston oil spray nozzle on the corresponding side through the left lubricating oil passage and the right lubricating oil passage. In the above oil circuit, the lubricating oil of the right lubricating oil channel is guided to the left lubricating oil channel through the matching oil channel. The structure is compact and can prevent the oil channel from leaking from the joint gap after passing through the joint of the left crankcase and the right crankcase. The piston oil spray nozzle is arranged facing the back of the piston, and the sprayed lubricating oil can directly reach the back of the piston. Since the temperature at the back of the piston is the highest, this arrangement can effectively ensure the lubrication and cooling effect of the piston.

[0012] Furthermore, a first oil passage and a second oil passage are respectively provided in the left crank and the crank pin along the axial direction thereof, the first oil passage and the second oil passage are connected through an oblique oil guide passage, and an oil injection hole corresponding to the two piston connecting rods is also provided on the crank pin; the first oil passage, the oblique oil guide passage and the second oil passage form the crankshaft lubricating oil passage. In this way, the oblique oil guide passage can guide the lubricating oil of the first passage into the second oil passage, one end of the oblique oil guide passage is provided at the end of the left crank, and the other end is provided on the crank pin, and the left crank and the crank pin are connected by the interference fit of the left crank at the end of the left crank, and can rotate synchronously, so that during the operation, the above-mentioned passages always keep in sync and keep connected. The oil injection holes provided correspond to the assembly positions of the two piston connecting rod heads respectively, and can lubricate and cool the piston connecting rod heads. The second oil passage provided in the crank pin can not only cool and lubricate the assembly end of the piston connecting rod head through the oil injection hole, but also cool the crank pin, effectively ensuring that the crank pin has a long service life.

[0013] Furthermore, the intake mechanism and the exhaust mechanism are installed in the cylinder head, and include a valve, a valve spring, an upper seat of the valve spring and a lower seat of the valve spring. The lower seat of the valve spring is fixedly connected to the body, the lower end of the valve spring is connected to the lower seat of the valve spring, the valve passes through the valve spring arrangement, and the upper end of the valve spring is clamped with the upper end of the valve by a locking clip; the intake camshaft and the exhaust camshaft are arranged at the front end of the intake mechanism and the exhaust mechanism, and four cams are arranged on the intake camshaft and the exhaust camshaft, and the four cams are divided into two groups, and the two groups of cams form an angle of 180 degrees relative to the axis of the intake camshaft; a rocker arm shaft is arranged between the intake camshaft and the intake mechanism, and between the exhaust camshaft and the exhaust mechanism, and four rocker arms are arranged on each rocker arm shaft, each rocker arm is in corresponding contact with the corresponding valve top, and the four cams on the intake camshaft and the exhaust camshaft correspond to the rocker arms one by one. When the intake camshaft and the exhaust camshaft rotate, one group of cams abuts against the corresponding rocker arm, squeezing the intake mechanism or the exhaust mechanism to realize intake or exhaust. In this way, the intake mechanism and the exhaust mechanism realize intake and exhaust by pressing down the top of the valve through the rocker arm on the rocker arm shaft, and the overall structure is compact.

[0014] Furthermore, a camshaft cooling oil passage connected to the cylinder head cooling oil passage is provided in the intake camshaft and the exhaust camshaft along the axial direction thereof, and a plurality of radial oil injection holes corresponding to the journals thereof are also provided on the intake camshaft and the exhaust camshaft. In this way, after the lubricating oil enters the cylinder head, it is introduced into the intake camshaft and the exhaust camshaft to cool the intake camshaft and the exhaust camshaft, and the radial oil injection holes are provided to cool and lubricate the camshaft.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. The horizontal double-bar engine is used in motorcycles. The overall structure is compact. The oil cooler for cooling the high-temperature oil in the lubrication system is located on the frame outside the engine, which further saves the space of the engine.

[0016] 2. The timing sprocket drive mechanism is located at one end of the shaft, has a compact structure, and can effectively reduce vibration.

[0017] 3. The engine is cooled by a combination of air cooling and oil cooling, which saves more space than the traditional air cooling combined with water cooling. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A schematic diagram of the three-dimensional structure of a horizontal twin-cylinder engine of a motorcycle in an embodiment; Figure 2 It is a cross-sectional structural schematic diagram of a horizontal twin-cylinder engine in the embodiment; Figure 3 It is a schematic diagram of the assembly structure of the intake and exhaust mechanism, the valve mechanism and the crankshaft connecting rod mechanism in the embodiment; Figure 4 It is a cross-sectional structural schematic diagram of the CVT transmission mechanism in the embodiment; Figure 5 Schematic diagram of the assembly structure of the input gear and the output gear in the embodiment; Figure 6 It is a schematic diagram of the disassembled structure of the CVT case in the embodiment; Figure 7 Schematic diagram of the connection structure between the crankcase and the external oil cooler in the embodiment; Figure 8 This is a schematic diagram of the distribution structure of the oil lubrication system after extraction in the embodiment; Fig. 9 Schematic diagram of the distribution structure of the lubricating oil circuits of the crankcase and the cylinder head in the embodiment; Fig.10 Schematic diagram of the cross-sectional structure of the intake camshaft in the embodiment. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. The components of the embodiments of the present invention generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the present invention.

[0020] It should be noted that similar numbers and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings. In the description of the present invention, it should be noted that the orientation or position relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. is based on the orientation or position relationship shown in the drawings, or the orientation or position relationship in which the invention product is usually placed when used, which is only for the convenience of describing the present invention 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, and therefore cannot be understood as a limitation of the present invention. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance. In addition, the terms "horizontal", "vertical", etc. do not mean that the components are absolutely horizontal or suspended, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted. In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0021] like Figure 1-Figure 5As shown, the horizontal twin-cylinder engine of the motorcycle provided in this embodiment comprises a body 1, two cylinders, two pistons 6, a fuel injection device, an ignition device, a crank connecting rod mechanism 7 and a valve mechanism 2, each set of cylinders is equipped with two intake mechanisms 3 and two exhaust mechanisms 4 (in specific implementation, three or four sets may be provided), the valve mechanism 2 comprises an intake camshaft 21 and an exhaust camshaft 23, and the intake camshaft 21 and the exhaust camshaft 23 are respectively provided at the same side end positions. An intake timing sprocket 22 and an exhaust timing sprocket 24 are provided; the crank-connecting rod mechanism 7 includes a left crank 71, a right crank 73 and a crank pin 72 installed between the left crank 71 and the right crank 73, two piston connecting rods 61 are sleeved in the middle of the sleeve crank pin 72, and a timing driving sprocket 74 is sleeved on the left crank 71. The timing driving sprocket 74 is located on the same side as the intake timing sprocket 22 and the exhaust timing sprocket 24, and is connected by a timing chain 25 (at the timing A guide plate and a tensioning plate are respectively provided on the left and right sides of the chain for tensioning and guiding the timing chain). A balance shaft driving gear 75 and a CVT driving pulley 81 are sequentially sleeved on the right crank 73 from the inside to the outside; a CVT driven pulley 82 is provided on one side of the CVT driving pulley 81, and the CVT driving pulley 81 and the CVT driven pulley 82 are connected by a belt 83. The CVT driven pulley 82 is sleeved and fixed on a main transmission shaft 84, and an input gear 85 is sleeved and fixed on the main transmission shaft 84. An output gear 88 connected to the input gear 85 is provided on one side of the input gear 85 (the CVT driving pulley 81, the CVT driven pulley 82, the belt and the main transmission shaft 84 together constitute a CVT transmission mechanism 8); a balance shaft 77 parallel to the right crank 73 is provided on one side of the right crank 73, and a balance shaft driven gear 76 meshing with the balance shaft driving gear 75 is sleeved on the balance shaft 77. The valve mechanism 2, the intake mechanism 3 and the exhaust mechanism 4 are all located at the front end of the engine (i.e., arranged toward the front of the motorcycle), the crank-connecting rod structure is located at the rear end of the body 1, and the transmission mechanism is distributed horizontally as a whole, i.e., forming a horizontal twin-cylinder engine. Compared with the vertical twin-cylinder engine, this arrangement has a smaller longitudinal assembly height. At the same time, the right crank 73 is used to drive the CVT driving pulley 81 to rotate, and the overall layout is compact. The intake timing sprocket 22 and the exhaust timing sprocket 24 are respectively located at the end positions of the intake camshaft 21 and the exhaust camshaft 23, which changes the installation position of the timing driven sprocket of the traditional twin-cylinder engine. The end position is close to the assembly end of the shaft, and relatively speaking, the vibration is smaller. When the crank-connecting rod mechanism 7 rotates after the piston 6 is ignited, it will drive the CVT driving pulley 81, the CVT driven pulley 82 and the main transmission shaft 84 sleeved thereon, and finally output the power to the output gear through the input gear 85 to achieve power output.When the right crank 73 rotates, the balance shaft driving gear 75 will drive the balance shaft driven gear 76 meshing therewith to rotate, thereby causing the balance shaft 77 to rotate. After the balance shaft 77 rotates, the vibration of the engine can be reduced.

[0022] like Figure 5 As shown, the input gear 85 and the output gear 88 are connected by an intermediate gear set. Specifically, the intermediate gear set includes a first helical tooth 86 and a second helical tooth 87. The first helical tooth 86 and the second helical tooth 87 are both sleeved on an intermediate shaft. The first helical tooth 86 is meshed with the input gear 85, and the second helical tooth 87 is meshed with the output gear 88. The input gear, the first helical tooth, the second helical tooth and the output gear are all helical gears.

[0023] Specifically, the engine body 1 in this embodiment includes a cylinder head cover 11, a cylinder head 12, a cylinder body 13, a crankcase, a left cover 16, a right cover 17 and a CVT cover 18. The cylinder head cover 11, the cylinder head 12 and the cylinder body 13 are connected front and back in sequence. The crankcase includes a left crankcase 14 and a right crankcase 15. The outer side of the left crankcase 14 is sealed with the left cover 16, and the right crankcase 15 is sealed with the right cover 17. The CVT cover 18 is connected with the outer side of the right cover 17 and together with it, forms a CVT case. A plurality of heat sinks are provided on the outer end surfaces of the cylinder head cover 11, the cylinder head 12 and the cylinder body 13. In this way, the crankcase and the CVT case in the engine body 1 are separated. The heat generated by the CVT case is higher than that of the crankcase. After separating the two, the hot air of the CVT case can be prevented from flowing into the crankcase, which affects the service life of the transmission parts in the crankcase. The cylinder head cover 11, the cylinder head 12 and the cylinder body 13 are connected to the combustion chamber. After a plurality of cooling fins are arranged circumferentially on the outer end surfaces of the above components, the heat generated by the above components can be taken away by air cooling.

[0024] like Figure 6As shown, an air inlet 171 and an air outlet 172 connected to the CVT housing are provided on the upper side of the right cover 17, the air inlet 171 is provided near the CVT driving pulley 81, and the air outlet 172 is provided near the CVT driven pulley 82; an air inlet chamber 181 connected to the air inlet 171 is provided on the CVT cover 18, and an air exhaust port 182 corresponding to the blades of the CVT driving pulley 81 is provided on the side of the air inlet chamber 181 facing the right cover 17. In this way, after the air inlet 171 and the air outlet 172 are provided on the right cover 17, the air inlet 171 and the air outlet 172 are both provided on the upper side of the right cover 17, and the mold opening is correspondingly simpler, which can effectively reduce the mold opening cost. When the exhaust duct is set upward, stones can be prevented from being thrown into the CVT housing. After the motorcycle engine is started, the CVT driving pulley 81 rotates, causing the blades on the driving pulley to rotate accordingly, forming a negative pressure outside the box, and sucking the cold air outside the box from the air inlet duct 171 to the air inlet chamber 181, and then passing through the air outlet to the driving pulley to cool the driving pulley. At the same time, under the action of the driving wheel blades, the air flows to the driven pulley, passes through the driven pulley, and is guided to the air outlet duct 172 along its side wall in a clockwise direction, and the hot air is guided out of the air outlet duct 172. Since the air outlet is set forward, when the hot air is discharged from the exhaust channel, the external cold air will directly blow the hot air in the opposite direction of riding, and will not flow to the front end, and the hot air flow can be taken away at the first time. The set air inlet chamber 181 can form a vortex in the air inlet chamber 181 after sucking the external cold air, thereby increasing the air flow rate.

[0025] Furthermore, a blocking rib 173 is provided on the side of the right cover 17 facing the CVT cover 18, the upper end of the blocking rib 173 is connected to the upper wall of the right cover 17, and the lower end extends in the axial direction of the CVT driven pulley 82; the blocking rib 173 is arranged obliquely, and the oblique direction is consistent with the air outlet 172. In this way, the blocking rib 173 can form a certain barrier to the air on the driven wheel side, preventing the hot air from being discharged from the air outlet 172, and part of the hot air enters the driving wheel through the space at the upper end of the driven wheel, thereby affecting the hot air discharge efficiency.

[0026] like Figure 7 , Figure 8As shown, it also includes an oil lubrication system 9, which includes an oil collecting chamber 91 arranged at the bottom of the crankcase body and a coarse filter 92, an oil pump 93, an external oil cooler 94, a fine filter 95 and a main oil circuit 96 which are connected in sequence, one end of the coarse filter 92 is immersed in the lubricating oil in the oil collecting chamber 91, the oil pump 93 is assembled in the crankcase body, the oil cooler is placed on the motorcycle frame outside the crankcase body, and is provided with an oil inlet pipeline and an oil outlet pipeline; the fine filter 95 is connected to the main oil circuit 96, and the oil pump 93 is installed in the crankcase body. The filter 95 and the coarse filter 92 are both arranged on the lower end surface of the crankcase body. The coarse filter 92 is connected to the oil inlet pipe of the oil pump 93 through the first oil guide channel arranged in the crankcase body. The oil outlet of the first oil guide channel is connected to the oil inlet pipeline of the oil cooler. The oil outlet pipeline of the oil cooler is connected to the fine filter 95 through the second oil guide channel arranged on the crankcase body. The inner end of the fine filter 95 is placed in the crankcase body, and the end is connected to the main oil channel 96 in the crankcase body. In this way, on the basis of setting the heat sink and the air inlet duct 171 and the air outlet duct 172 for air cooling and heat dissipation, the oil lubrication system 9 can realize oil cooling for the crankshaft, crankcase, cylinder block and cylinder head. After long-term circulation, the lubricating oil in the oil collecting chamber 91 will produce some impurities. At the same time, after the oil cooling and lubrication of each component, the temperature of the lubricating oil will rise after falling back into the oil collecting chamber 91, thereby affecting the subsequent lubrication and cooling. After the high-temperature lubricating oil in the oil collecting chamber is initially filtered by the coarse filter 92, it is pumped to the oil cooler outside the crankcase body by the oil pump 93, and after being cooled by the oil cooler, it is led out from the oil outlet pipeline of the oil cooler to the second oil guide channel of the crankcase body, and finally enters the fine filter 95, and is further finely filtered by the fine filter 95. Finally, the cooled and filtered lubricating oil is transported to various oil circuits through the main oil channel 96 on the crankcase body to lubricate various transmission parts in the crankcase body. The coarse filter 92 and the fine filter 95 are installed on the lower end surface of the crankcase body, located on the same side, and are relatively convenient to install and disassemble, without standing on both sides to install or disassemble separately. The oil cooler is outside the crankcase body, on the motorcycle frame, and does not occupy the space of the engine, which can effectively reduce the size of the engine.

[0027] Furthermore, the installation height of the coarse filter is lower than that of the fine filter 95, and the oil lubrication system 9 also includes a main transmission shaft lubrication oil passage 97, a crankshaft lubrication oil passage 98, a box oil outlet passage, two piston lubrication oil passages 99, a cylinder cooling oil passage 99a, and a cylinder head cooling oil passage 99b, which are connected to the main oil passage 96. In this way, after the coarse filter is set to a lower installation position, the path between the oil collecting chamber and the coarse filter can be shortened. After the lubricating oil is cooled and finely filtered, the cooled lubricating oil can be pumped to the main transmission shaft, crankshaft, crankcase, piston 6, cylinder body and cylinder head through the main oil passage 96 to cool and lubricate various components in the engine that are at high temperatures.

[0028] like Fig. 9As shown, the crankcase body is connected by a left crankcase 14 and a right crankcase 15; two piston oil nozzles 994 are arranged in the crankcase body facing the back of the piston 6, and a left lubricating oil passage 991 and a right lubricating oil passage 992 are respectively arranged on the docking surfaces of the left crankcase 14 and the right crankcase 15 with the cylinder body, and one end of the right lubricating oil passage 992 is connected with the oil outlet passage of the case body. The two piston lubricating oil passages 99 are respectively arranged in the left crankcase 14 and the right crankcase 15, and are connected with the left lubricating oil passage 991 and the right lubricating oil passage 992 on the corresponding sides; a matching oil passage 993 for connecting the left lubricating oil passage 991 and the right lubricating oil passage 992 is provided on the case docking surface of the cylinder body, and the left and right sides of the matching oil passage 993 correspond to the left lubricating oil passage 991 and the right lubricating oil passage 992 respectively. In this way, when the oil pump 93 pumps the lubricating oil from the crankcase to the cylinder body, the lubricating oil passes through the crankcase oil outlet channel, and then enters the right lubricating oil channel 992, the matching oil channel 993 and the left lubricating oil channel 991, and then is guided to the piston oil nozzle 994 on the corresponding side through the left lubricating oil channel 991 and the right lubricating oil channel 992. In the above oil circuit, the lubricating oil of the right lubricating oil channel 992 is guided to the left lubricating oil channel 991 through the matching oil channel 993. The structure is compact and can prevent the oil channel from leaking from the joint gap after passing through the joint of the left crankcase 14 and the right crankcase 15. The piston oil nozzle 994 is arranged facing the back of the piston 6, and the sprayed lubricating oil can directly reach the back of the piston 6. Since the temperature at the back of the piston 6 is the highest, this arrangement can effectively ensure the lubrication and cooling effect of the piston 6.

[0029] Furthermore, a first oil passage 711 and a second oil passage 721 are respectively provided in the left crank 71 and the crank pin 72 along their axial direction, the first oil passage 711 and the second oil passage 721 are connected through an oblique oil guide passage, and the crank pin 72 is also provided with oil injection holes corresponding to the two piston connecting rods 61; the first oil passage 711, the oblique oil guide passage and the second oil passage 721 form the crankshaft lubricating oil passage 98; an end oil seal is sleeved on one end of the second oil passage 721 close to the crank pin 72. In this way, the oblique oil guide passage can guide the lubricating oil of the first passage to the second oil passage 721, one end of the oblique oil guide passage is provided at the end of the left crank 71, and the other end is provided on the crank pin 72, and the left crank 71 and the crank pin 72 are connected by the interference fit of the left crank at the end of the left crank 71, and can rotate synchronously, so that during the operation, the above passages always keep synchronization and keep connected. The oil injection holes are respectively corresponding to the assembly positions of the two piston connecting rods 61, and can lubricate and cool the small end of the piston connecting rod 61. The second oil passage 721 provided in the crank pin 72 can not only cool and lubricate the assembly end of the piston connecting rod 61 through the oil injection holes, but also cool the crank pin 72, effectively ensuring that the crank pin 72 has a long service life.

[0030] like Figure 3As shown, the intake mechanism 3 and the exhaust mechanism 4 are installed in the cylinder head 12, including valves, valve springs, valve spring upper seats and valve spring lower tables, the valve spring lower seats are fixedly connected to the engine body 1, the lower end of the valve spring is connected to the valve spring lower seat, the valve is arranged through the valve spring, and the upper end of the valve spring is clamped with the upper end of the valve; the intake camshaft 21 and the exhaust camshaft 23 are arranged at the front ends of the intake mechanism 3 and the exhaust mechanism 4, and four cams are arranged on the intake camshaft 21 and the exhaust camshaft 23, and the four cams are divided into two groups, and the two groups of cams are opposite to each other. The axis of the intake camshaft 21 forms an angle of 180 degrees; a rocker shaft 5 is provided between the intake camshaft 21 and the intake mechanism 3, and between the exhaust camshaft 23 and the exhaust mechanism 4. Four rocker arms 51 are provided on each rocker shaft 5. Each rocker arm 51 is in contact with the corresponding valve top. The four cams on the intake camshaft 21 and the exhaust camshaft 23 correspond to the rocker arms one by one. When the intake camshaft and the exhaust camshaft 23 rotate, one group of cams abuts against the corresponding rocker arms, squeezing the intake mechanism 3 or the exhaust mechanism 4 to achieve intake or exhaust. In this way, the intake mechanism 3 and the exhaust mechanism 4 realize intake and exhaust by pressing the valve top downward through the rocker arms on the rocker shaft 5, and the overall structure is compact.

[0031] like Fig.10 As shown, a camshaft cooling oil passage 211 connected to the cylinder head cooling oil passage 99b is provided in the intake camshaft 21 and the exhaust camshaft 23 along the axial direction thereof, and a plurality of radial oil injection holes 212 corresponding to the journals thereof are also provided on the intake camshaft 21 and the exhaust camshaft 23. In this way, after the lubricating oil enters the cylinder head, it is introduced into the intake camshaft 21 and the exhaust camshaft 23 to cool the intake camshaft 21 and the exhaust camshaft 23, and the radial oil injection holes provided cool and lubricate each camshaft.

[0032] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the technical solution. Those skilled in the art should understand that those modifications or equivalent substitutions of the technical solution of the present invention that do not depart from the purpose and scope of the technical solution should be included in the scope of the claims of the present invention.

Claims

1. A horizontal twin-cylinder engine for a motorcycle, comprising a body, two cylinders, two pistons, a fuel injection device, an ignition device, a crank-connecting rod mechanism and a valve mechanism, each set of cylinders is equipped with a plurality of intake mechanisms and exhaust mechanisms, the valve mechanism comprises an intake camshaft and an exhaust camshaft, an intake timing sprocket and an exhaust timing sprocket are respectively sleeved at the same side end positions of the intake camshaft and the exhaust camshaft, characterized in that: The crank-connecting rod mechanism is located at the rear end of the valve mechanism, and includes a left crank, a right crank and a crank pin. Two piston connecting rods are sleeved on the middle part of the crank pin. A timing driving sprocket is sleeved on the left crank. The timing driving sprocket is located on the same side as the intake timing sprocket and the exhaust timing sprocket, and are connected by a timing chain. A balance shaft driving gear and a CVT driving pulley are sleeved on the right crank from the inside to the outside in sequence; a CVT driven pulley is provided on one side of the CVT driving pulley, and the CVT driving pulley and the CVT driven pulley are connected by a belt drive, and the CVT driven pulley is sleeved and fixed on a main transmission shaft, and an input gear is sleeved and fixed on the main transmission shaft, and an output gear connected to the input gear is provided on one side of the input gear; a balance shaft parallel to the right crank is provided on one side, and a balance shaft driven gear meshing with the balance shaft driving gear is sleeved on the balance shaft.

2. The horizontal twin-cylinder engine for a motorcycle according to claim 1, characterized in that: The engine body includes a cylinder head cover, a cylinder head, a cylinder body, a crankcase, a left cover, a right cover and a CVT cover. The cylinder head cover, the cylinder head and the cylinder body are connected front to back in sequence. The crankcase includes a left crankcase and a right crankcase. The outer side of the left crankcase is sealed with the left cover, and the right crankcase is sealed with the right cover. The CVT cover is connected to the outer side of the right cover and together with it forms a CVT case body. A plurality of heat sinks are provided on the outer end surfaces of the cylinder head cover, the cylinder head and the cylinder body.

3. The horizontal twin-cylinder engine for motorcycle according to claim 2, characterized in that: An air inlet duct and an air outlet duct connected to the CVT case are provided on the upper side of the right cover, the air inlet duct is arranged close to the side of the CVT driving pulley, and the air outlet duct is arranged close to the side of the CVT driven pulley; an air inlet chamber connected to the air inlet duct is provided on the CVT cover, and an air exhaust port corresponding to the blades of the CVT driving pulley is provided on the side of the air inlet chamber facing the right cover.

4. The horizontal twin-cylinder engine for a motorcycle according to claim 3, characterized in that: A barrier rib is provided on the side of the right cover facing the CVT cover, the upper end of the barrier rib is connected to the upper wall of the right cover, and the lower end extends toward the CVT driven pulley shaft; the barrier rib is obliquely arranged, and the inclination direction is consistent with the air outlet duct.

5. The horizontal twin-cylinder engine for motorcycle according to claim 1, 2, 3 or 4, characterized in that: It also includes an oil lubrication system, which includes an oil collecting chamber arranged at the bottom of the crankcase body and a coarse filter, an oil pump, an external oil cooler, a fine filter and a main oil circuit which are connected in sequence, one end of the coarse filter is immersed in the lubricating oil in the oil collecting chamber, the oil pump is assembled in the crankcase body, the oil cooler is placed on a motorcycle frame outside the crankcase body, and is provided with an oil inlet pipeline and an oil outlet pipeline; the fine filter and the coarse filter are both arranged on the lower end surface of the crankcase body, the coarse filter is connected to the oil inlet pipe of the oil pump through a first oil guide channel arranged in the crankcase body, the oil outlet of the first oil guide channel is connected to the oil inlet pipeline of the oil cooler, and the oil outlet pipeline of the oil cooler is connected to the fine filter through a second oil guide channel arranged on the crankcase body; the inner end of the fine filter is placed in the crankcase body, and the end is connected to the main oil channel in the crankcase body.

6. The horizontal twin-cylinder engine for motorcycle according to claim 5, characterized in that: The installation height of the coarse filter is lower than that of the fine filter. The oil lubrication system also includes a main transmission shaft lubricating oil channel, a crankshaft lubricating oil channel, a box oil outlet channel, two piston lubricating oil channels, a cylinder cooling oil channel and a cylinder head cooling oil channel connected to the main oil channel.

7. The horizontal twin-cylinder engine for a motorcycle according to claim 6, characterized in that: The crankcase body is formed by connecting a left crankcase and a right crankcase; two piston oil spray nozzles arranged toward the back of the piston are arranged in the crankcase body, and a left lubricating oil channel and a right lubricating oil channel are respectively arranged on the docking surfaces of the left crankcase and the right crankcase with the cylinder body, and one end of the right lubricating oil channel is connected with the oil outlet channel of the case body, and the two piston lubricating oil channels are respectively arranged in the left crankcase and the right crankcase, and are connected with the left lubricating oil channel and the right lubricating oil channel on the corresponding sides; a matching oil channel for connecting the left lubricating oil channel and the right lubricating oil channel is provided on the case docking surface of the cylinder body, and the left and right sides of the matching oil channel correspond to the left lubricating oil channel and the right lubricating oil channel respectively.

8. The horizontal twin-cylinder engine for a motorcycle according to claim 6, characterized in that: A first oil passage and a second oil passage are respectively provided in the left crank and the crank pin along their axial direction, the first oil passage and the second oil passage are connected by an oblique oil guide passage, and an oil injection hole corresponding to the two piston connecting rods is also provided on the crank pin; the first oil passage, the oblique oil guide passage and the second oil passage form the crankshaft lubricating oil passage.

9. The horizontal twin-cylinder engine for a motorcycle according to claim 1 or 2 or 3 or 4 or 6 or 7 or 8, characterized in that: The intake mechanism and the exhaust mechanism are installed in the cylinder head, and include valves, valve springs and valve spring seats. The valve spring seats are fixedly connected to the engine body, the lower end of the valve spring is connected to the valve spring seat, the valve is arranged through the valve spring, and the upper end of the valve spring is clamped with the upper end of the valve; the intake camshaft and the exhaust camshaft are arranged at the front ends of the intake mechanism and the exhaust mechanism, and four cams are arranged on the intake camshaft and the exhaust camshaft, and the four cams are divided into two groups, and the two groups of cams form an angle of 180 degrees relative to the axis of the intake camshaft; a rocker arm shaft is arranged between the intake camshaft and the intake mechanism, and between the exhaust camshaft and the exhaust mechanism, and four rocker arms are arranged on each rocker arm shaft, each rocker arm is in corresponding contact with the corresponding valve top, and the four cams on the intake camshaft and the exhaust camshaft correspond to the rocker arms one by one. When the intake camshaft and the exhaust camshaft rotate, one group of cams abuts against the corresponding rocker arm, and squeezes the intake mechanism or the exhaust mechanism to realize intake or exhaust.

10. The horizontal twin-cylinder engine for a motorcycle according to claim 9, characterized in that: A camshaft cooling oil passage connected to the cylinder head cooling oil passage is provided in the intake camshaft and the exhaust camshaft along their axial direction, and a plurality of radial oil injection holes corresponding to their journals are also provided on the intake camshaft and the exhaust camshaft.

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