Motorcycle water-cooled engine structure

Abstract

The utility model relates to a motorcycle water -cooling engine structure, and the engine includes cylinder part and the crankcase with crankshaft, and there is the joint surface between the crankcase and cylinder part, the cylinder part has cylinder head and cylinder body, the cylinder part has cylinder hole center line, and the cylinder part is along cylinder hole center line from the joint surface to the front of motorcycle and sets up, and the water jacket is equipped in the cylinder head, the engine has liquid cooling device and air intake system, and the liquid cooling device has radiator and fan, the cylinder head has water pump and thermostat, and the water pump is connected with radiator with coolant output pipe, and the thermostat is connected with radiator with backflow pipe, by the motorcycle overhead view, the inner side edge of radiator along the motorcycle width direction is compared with the outer side edge of fan and is arranged more outside, the backflow pipe has the bridging section that simultaneously straddles cylinder hole center line and vehicle center line and cylinder body in the left and right sides of vehicle width direction, by the motorcycle side view, at least one part of radiator is superimposed on fan and crankshaft, and the bridging section is arranged to pass through the safety area between the upper of crankcase and the lower of air intake system.

Description

Technical Field

[0001] This utility model relates to a motorcycle water-cooled engine structure, and more particularly to a motorcycle water-cooled engine structure that enables the intake system to perform heat dissipation on the cross-connection section of the return pipe and avoids the formation of air plugs in the return pipe. Background Technology

[0002] like Figure 1 As shown, a radiator 11 is installed on one side of the liquid-cooled engine 1 of a motorcycle. The radiator 11 uses a coolant inlet pipe 111 to introduce coolant into the cylinder section 12 of the engine 1 to cool the cylinder section 12. The cooled hot liquid flows back from the cylinder section 12 to the radiator 11 through the hot liquid return pipe 112 for further cooling. The hot liquid return pipe 112 starts from the outlet 121 of the cylinder section 12, goes down and then horizontally around the bottom of the cylinder section 12, and then connects upward to the return port 113 of the radiator 11. Specifically, the hot liquid return pipe 112 is arranged in a slightly U-shape around the cylinder section 12.

[0003] like Figure 1 As shown, when coolant is added to the radiator 11, the coolant cannot flow back to the radiator 11 by its own gravity due to the U-shaped arrangement of the hot liquid return pipe 112. That is, without external force to push the coolant, a void will form in the rising section, which will affect the heat dissipation effect of the radiator 11. Therefore, the engineer or driver must start the engine 1 to make the water pump 122 in the cylinder head 12 work to help push the coolant through the rising section into the radiator 11, so that the radiator 11 and the water jacket (not shown in the figure) in the cylinder head 12 that provides coolant flow are both filled with coolant. In addition, the hot liquid return pipe 112 is arranged below the cylinder head 12, and the hot return fluid in the hot liquid return pipe 112 will be affected by the high temperature of the cylinder head 12 and the exhaust pipe.

[0004] Therefore, how to provide a water-cooled engine structure for motorcycles, in which coolant can fill the coolant circulation path by its own weight without starting the engine and water pump when adding coolant to the radiator, has become an urgent issue for motorcycle manufacturers to solve. Utility Model Content

[0005] [The problem that the utility model aims to solve]

[0006] The main purpose of this utility model is to provide a water-cooled engine structure for motorcycles, which overcomes the problem of air locks easily forming in the hot return pipe of known engine coolant.

[0007] Technical means to solve the problem

[0008] Therefore, this utility model provides a water-cooled engine structure for a motorcycle. The motorcycle engine includes at least a cylinder section and a crankcase with a crankshaft connected to the cylinder section, the crankcase and the cylinder section having a mating surface; the cylinder section includes at least a cylinder head and a cylinder body connected to one end of the cylinder head; the cylinder section has a cylinder bore centerline, the cylinder section extending from the mating surface towards the front of the motorcycle along the cylinder bore centerline, and the cylinder head has a water jacket for coolant flow; the engine is equipped with a liquid cooling device containing coolant and an intake system that provides fresh external air, the liquid cooling device including at least a radiator and A fan is located on one side of the radiator; the cylinder head is equipped with a water pump and a thermostat, the water pump is connected to the radiator via a coolant output pipe, and the thermostat is connected to the radiator via a return pipe; viewed from above by the motorcycle, the inner edge of the radiator along the width direction of the motorcycle is positioned further outward than the outer edge of the fan; the return pipe has a crossover section that simultaneously crosses the centerline of the cylinder bore, the centerline of the vehicle, and the cylinder body on the left and right sides in the width direction; viewed from the side by the motorcycle, at least a portion of the radiator is superimposed on the fan and the crankshaft; the crossover section is configured to pass through a safe area between the top of the crankcase and the bottom of the intake system.

[0009] Therefore, in some embodiments of this utility model, a water-cooled engine structure for a motorcycle is provided, wherein, viewed from the side of the motorcycle, the top edge of the crossover section of the return pipe is higher than one or both of the top edge of the cylinder head of the cylinder section and the top edge of the cylinder body of the cylinder body in the vertical direction of the motorcycle.

[0010] Therefore, in some embodiments of this utility model, a water-cooled engine structure for a motorcycle is provided, wherein, viewed from above by the motorcycle, at least a portion of the bridging section of the return pipe is located closer to the rear of the motorcycle than the outlet of the thermostat and the hot liquid recovery port of the radiator.

[0011] Therefore, in some embodiments of this utility model, a water-cooled engine structure for a motorcycle is provided, wherein, viewed from above by the motorcycle, at least a portion of the bridging section of the return pipe is disposed at a position closer to the rear of the motorcycle than one or both of the mating surface between the cylinder section and the crankcase and the throttle body of the intake system.

[0012] Therefore, in some embodiments of this utility model, a water-cooled engine structure for a motorcycle is provided, wherein, viewed from the perspective of the motorcycle, at least a portion of the crossover section of the return pipe is positioned closer to the rear of the motorcycle than the axis of the crankshaft.

[0013] Therefore, in some embodiments of this utility model, a water-cooled engine structure for a motorcycle is provided, wherein the motorcycle has a rear wheel; viewed from above, the cross-connection section of the return pipe is disposed in front of at least one or more of the following in the longitudinal direction of the motorcycle: the front edge of the muffler of the exhaust pipe, the rear edge of the radiator, and the front edge of the rear wheel.

[0014] Therefore, in some embodiments of this utility model, a water-cooled engine structure for a motorcycle is provided, wherein the distance between the radiator and the center line of the cylinder bore of the cylinder section in the width direction of the motorcycle is set to be greater than the distance between the thermostat and the center line of the cylinder bore of the cylinder section.

[0015] Therefore, in some embodiments of this utility model, a water-cooled engine structure for a motorcycle is provided, wherein in the vertical direction of the motorcycle, the outlet of the thermostat is configured to be higher than the top edge of the cylinder head, and the top edge of the hot liquid recovery port of the radiator is configured to be higher than the top edge of the outlet of the thermostat.

[0016] Therefore, in some embodiments of this utility model, a water-cooled engine structure for a motorcycle is provided, wherein the outlet of the thermostat is positioned higher than the inlet of the water pump in the vertical direction of the motorcycle.

[0017] [Effects of the utility model]

[0018] The advantages of this invention are: it does not affect the use of space under the seat, and it can keep the crossover section away from the high temperature of the cylinder head; at the same time, it can increase the height of the crossover section to avoid damage from foreign objects on the ground; it can also enable the intake system to dissipate heat from the crossover section of the return pipe, and prevent air locks from forming in the return pipe.

[0019] The effect achieved by this invention is that it can make the flow path of hot water liquid smooth after cooling and heat dissipation, thereby avoiding air blockage in the return pipe.

[0020] The effect achieved by this utility model is that it can keep the bridging section away from the high temperature of the cylinder head, thus preventing the bridging section of the return pipe from being affected by the high temperature of the cylinder head.

[0021] The advantages of this invention are: it allows the bridging section to be kept away from the high-temperature cylinder head; and it allows the intake system to perform heat dissipation on the bridging section of the return pipe.

[0022] The advantages of this invention are: it allows the bridging section to be kept away from the high-temperature cylinder head, thus preventing the bridging section of the return pipe from being affected by the high-temperature cylinder head and improving the durability of the return pipe.

[0023] The advantages of this invention are: it allows the bridging section to be kept away from the high-temperature cylinder head and exhaust pipe, preventing the bridging section of the return pipe from being affected by the high-temperature cylinder head and exhaust pipe, and also preventing the bridging section of the return pipe from being damaged by foreign objects on the ground.

[0024] The advantages of this invention are: it can make the flow path of hot water liquid smooth after cooling and heat dissipation, thereby avoiding air lock in the return pipe, and the bridging section can be kept away from the high temperature cylinder head and exhaust pipe, so as to avoid the bridging section of the return pipe being affected by the high temperature cylinder head and exhaust pipe.

[0025] The advantages of this invention are: it can make the flow path of hot water liquid smooth after cooling and heat dissipation, thereby improving the durability of the return pipe.

[0026] The effect achieved by this invention is that it can make the flow path of hot water liquid smooth after cooling and heat dissipation, thereby avoiding air blockage in the return pipe. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the radiator configuration of a known engine.

[0028] Figure 2 This is a side view of the motorcycle of this utility model.

[0029] Figure 3 This is a top view schematic diagram of the engine of this utility model.

[0030] Figure 4 This is a front view schematic diagram of the engine of this utility model.

[0031] Figure 5 This is a schematic diagram of the water jacket of this utility model.

[0032] Figure 6 This is a side view of the engine of this utility model.

[0033] List of reference numerals

[0034] 1: Engine

[0035] 11: Radiator

[0036] 111: Inlet pipe; 112: Hot liquid return pipe

[0037] 113: Recycling Port

[0038] 12: Cylinder section

[0039] 121: Water outlet; 122: Water pump

[0040] 2: Motorcycle

[0041] 2a: Vehicle centerline

[0042] 3: Chassis Unit

[0043] 31: Head tube section

[0044] 32: Steering mechanism

[0045] 33: Downcomer section

[0046] 34: Foot pedal tube section; 341: Foot pedal cross tube.

[0047] 35: Side frame section

[0048] 351: Ascending segment; 352: Extended segment

[0049] 353: Auxiliary pipe; 354: Extension piece

[0050] 4: Seat cushion

[0051] 5: Storage box

[0052] 6: Engine

[0053] 61: Cylinder section

[0054] 61a: Cylinder bore centerline

[0055] 611: Cylinder head cover

[0056] 612: Cylinder head; 6121: Cylinder head top edge; 613: Cylinder body

[0057] 6131: Cylinder body top edge

[0058] 614: Water pump; 6141: Inlet

[0059] 615: Water Jacket

[0060] 6151: Coolant inlet; 6152: Coolant outlet; 616: Thermostat

[0061] 6161: Export; 6161a: Top edge

[0062] 62: Transmission Unit

[0063] 63: Crankcase

[0064] 63a: mating surface

[0065] 631: Crankshaft; 6311: Shaft Axis; 7: Liquid Cooling Device

[0066] 71: Fan

[0067] 71a: Outer edge

[0068] 72: Radiator

[0069] 72a: Hydrothermal recovery port; 72b: Inner edge

[0070] 721: Water inlet pipe; 722: Water inlet.

[0071] 723: Cover 724: Overflow pipe

[0072] 725: Heat dissipation section

[0073] 73: Fairing

[0074] 74: Coolant outlet pipe

[0075] 75: Return pipe

[0076] 751: Bridging segment; 7511: Top edge

[0077] 8: Body Cover Unit

[0078] 81: Hood 82: Front hood

[0079] 83: Knee cover 84: Side body cover

[0080] 85: Central vehicle body cover

[0081] 9: Intake System

[0082] 91: Filter unit; 92: Vent pipe

[0083] 93: Throttling valve body; 94: Intake pipe

[0084] A: Safe Zone

[0085] D: Front fork unit

[0086] E: Foot pedal

[0087] M: Exhaust pipe M1: Muffler

[0088] FW: Front wheel

[0089] RW: Rear wheel

[0090] P: Footrest

[0091] T: Fuel tank

[0092] R1: Distance

[0093] R2: Distance. Detailed Implementation

[0094] To better understand the structure of this utility model and the effects it can achieve, the following description is provided in conjunction with the accompanying drawings.

[0095] First, please refer to Figure 2As shown, the motorcycle 2 of this utility model has a frame unit 3, a seat 4 disposed on the frame unit 3, and an engine 6.

[0096] like Figure 2 As shown in the following description, the left and right sides of the motorcycle 2 are defined with the driver's left side as the left side and the driver's right side as the right side when the driver is riding on the motorcycle 2. The frame unit 3 has a head tube 31 pivotally mounted at the front. A steering mechanism 32 is connected above the head tube 31. A downpipe 33 is connected to the head tube 31 towards the rear of the motorcycle 2. Below the downpipe 33 are a pair of slightly horizontal footpipes 34 extending towards the rear of the motorcycle 2. A footpipe cross tube 341 connects the end of the downpipe 33 to the pair of footpipes 34. A pair of side frame sections 35 extend from the footpipes 34 towards the rear of the motorcycle. The side frame sections 35 have a sloping edge adjacent to the footpipes 34. The rising section 351 and the extension section 352 located at the rear of the motorcycle 2 are provided with an auxiliary tube 353 between the rising sections 351 of the left and right side frame portions 35, and a pair of extension members 354 extending from the left and right sides of the rising section 351 to the rear of the motorcycle 2 near the foot tube portion 34; a front fork unit D composed of a front shock absorber is pivotally mounted below the head tube portion 31, and a front wheel FW is pivotally mounted at the lower end of the front fork unit D; a footrest E for passengers to rest their feet is provided on the rising section 351 of the side frame portion 35.

[0097] like Figure 2 As shown, the frame unit 3 has a slightly flat footrest P on its slightly horizontal foot tube section 34, which forms a flat footrest for the driver. The internal space defined between the two slightly horizontal foot tube sections 34 is equipped with a fuel tank T for storing fuel for the combustion of the engine 6. The engine 6 is connected to the frame unit 3 and is located further rearward of the fuel tank T.

[0098] like Figure 2 As shown, the side frame portion 35 has a seat cushion 4 for the driver to sit on above the extension section 352, and a storage box 5 is provided on the extension section 352 and below the seat cushion 4. The engine 6 is locked to the auxiliary tube 353 and the extension member 354 of the side frame portion 35, and the engine 6 is supported on the frame unit 3 in a swingable manner. The engine 6 drives the rear wheel RW.

[0099] like Figure 2 , 3As shown, the engine 6 (power unit) is an internal combustion engine; the engine 6 includes a cylinder section 61 and a transmission section 62; an exhaust pipe M is provided on one side of the engine 6, and the exhaust pipe M extends from the outside of the engine 6 toward the rear of the motorcycle 2; a liquid cooling device 7 is provided on one side of the engine 6, and the liquid cooling device 7 may be located on the same side or different side of the engine 6 as the exhaust pipe M; this utility model is illustrated by the example of the liquid cooling device 7 and the exhaust pipe M being located on the same side of the engine 6.

[0100] like Figure 2 , 3 As shown in Figure 5, the cylinder section 61 extends forward of the motorcycle 2 at a slightly inclined manner and partially extends beyond the rising section 351 of the side frame section 35, meaning that the portion of the cylinder section 61 extending forward of the motorcycle 2 extends further forward than the rising section 351 of the side frame section 35. The cylinder section 61, from front to rear of the motorcycle 2, consists of a cylinder head cover 611, a cylinder head 612, and a cylinder body 613. One end of the cylinder body 613 facing downwards from the motorcycle 2 is connected to a crankcase 63 containing a crankshaft 631. A transmission section 62 is provided on one side of the crankcase 63, which includes a belt-driven continuously variable transmission system (not shown in the figure). The cylinder section 61 has a cylinder bore centerline 61a, and a mating surface 63a exists between the crankcase 63 and the cylinder section 61. The cylinder section 61 extends along the cylinder bore centerline 61a... 1a extends from the mating surface 63a toward the front of the motorcycle 2; the cylinder bore centerline 61a is set slightly perpendicular to the mating surface 63a; a water pump 614 for pumping coolant is provided on one side of the cylinder section 61, and the water pump 614 is provided on the cylinder head 612 in this invention; at least one or more water jackets 615 for coolant to flow are provided inside the cylinder section 61, and the water jacket 615 has a coolant inlet 6151 and a coolant outlet 6152. On the other side of the cylinder section 61 where the water pump 614 is provided, a thermostat 616 for controlling whether coolant flows out of the water jacket 615 or not is provided. More specifically, the thermostat 616 is provided on the outer edge of the coolant outlet 6152 of the water jacket 615. In the embodiment of this invention, the water pump 614 and the thermostat 616 are respectively provided on two opposite sides of the cylinder head 612.

[0101] like Figure 2 , 3As shown, the cylinder head 612 of the cylinder section 61 of the engine 6 is connected to an intake system 9 that provides clean fresh air for combustion of the engine 6. The intake system 9 includes a filter unit 91 that filters external air into clean air, a vent pipe 92 connected to the filter unit 91 and allowing clean air to flow through, a throttle valve body 93 connected to the other end of the vent pipe 92 and adjusting the amount of clean air flow, and an intake pipe 94 connected to the throttle valve body 93 and the cylinder head 612. The external fresh clean air required for combustion of the cylinder section 61 of the engine 6 is filtered by the filter unit 91 of the intake system 9, flows through the vent pipe 92 into the throttle valve body 93 and is then regulated before entering the combustion chamber (not shown in the figure) of the cylinder section 61 to combust with the fuel in the fuel tank T, thereby enabling the engine 6 to continue operating.

[0102] like Figure 2 As shown, the motorcycle 2 has a body cover unit 8 on the outer periphery of the frame unit 3. The body cover unit 8 includes a front cover 81 that can cover part of the steering mechanism 32, a front body cover 82 that covers the front of the body, a knee cover 83 located behind the front body cover 82, side body covers 84 located on both sides below the seat 4, and a central body cover 85 located below the seat 4. The central body cover 85 can be extended from the two side body covers 84 or be a separate cover.

[0103] like Figure 2 , 3As shown in Figures 4 and 5, the liquid cooling device 7 is located on one side of the motorcycle 2 in the width direction; that is, the liquid cooling device 7 is located on the other side of the engine 6 where the belt-driven continuously variable transmission system is installed. The liquid cooling device 7 has a fan 71 connected to the crankshaft 631 inside the crankcase 63, a radiator 72 located further outward of the fan 71 in the width direction, and a shroud 73 located outside the radiator 72. Viewed from the side of the motorcycle 2, at least a portion of the radiator 72 overlaps with the fan 71 and the crankshaft 631. The radiator 72 has a plurality of cooling fins. A water inlet pipe 721 is integrally formed on the top of the radiator 72, which allows external cold water to be added into the radiator 72. The end of the water inlet pipe 721 has a water inlet 722 that connects to the water inlet pipe 721. The top cover of the water inlet 722 is provided with a self-closing... With the disassembled cover 723, the water inlet pipe 721 is located below the water inlet 722, where an overflow pipe 724 is provided for overflow when the water level inside the radiator 72 is too high. A coolant outlet pipe 74 is located below the radiator 72. One end of the coolant outlet pipe 74 is connected to the bottom of the radiator 72, and the other end is connected to the water pump 614 of the cylinder head 612. Thus, when the engine 6 is started, the water pump 614 is also driven to operate, so that the water pump 614 can draw coolant from the radiator 72 and send it into the water jacket 615 provided in the cylinder head 61 for coolant circulation. The coolant enters from the coolant inlet 6151 of the water jacket 615 and flows out from the coolant outlet 6152. After passing through the thermostat 616, it flows back into the radiator 72 through the return pipe 75, thereby achieving the purpose of cooling the cylinder head 61 of the engine 6.

[0104] like Figure 3 , 4As shown, the water inlet pipe 721 of the radiator 72 is equipped with a return pipe 75, which is connected to the thermostat 616 of the cylinder section 61 of the engine 6. This allows the hot water cooled by the cylinder section 61 of the engine 6 to flow back into the radiator 72 through the return pipe 75 for cooling. When the engine 6 drives the fan 71 to rotate, it can introduce cold air from the outside to cool the radiator 72. After the hot water cooled by the cylinder section 61 of the engine 6 is returned to the radiator 72 through the return pipe 75, the negative pressure generated by the fan 71 introduces cold air from the outside for cooling. The radiator 72 is mounted on the outer side of the fan 71 along the width direction of the motorcycle 2. In this way, the radiator 72 draws in cold air from the outside through the fan 71, so that the heat dissipation part 725 of the radiator 72 can be cooled by the cold air. It should also be noted that, when viewed from above the motorcycle 2, the inner edge 72b of the radiator 72 along the width direction of the motorcycle 2 is positioned further outward than the outer edge 71a of the fan 71. That is, the overall side view area of ​​the radiator 72 is larger than that of the fan 71, thereby improving the heat dissipation effect of the radiator 72.

[0105] like Figure 2 , 3 As shown in Figure 4, the air guide 73 is disposed on the outside of the heat sink 72, that is, the heat sink 72 is located between the air guide 73 and the fan 71; the air guide 73 of this utility model is implemented with a grid-shaped air guide structure.

[0106] like Figure 3 , 4As shown in Figure 6, one end of the return pipe 75 of this utility model is connected to the thermostat 616 and the other end is connected to the water inlet pipe 721 of the radiator 72. The return pipe 75 has a bridging section 751 that spans the cylinder bore centerline 61a, the vehicle centerline 2a, and the cylinder body 613 on the left and right sides in the vehicle width direction. The bridging section 751 is configured to pass through the safety area A above the crankcase 63 and below the intake system 9; thereby avoiding the return pipe The hot return fluid after cooling the engine 6 is affected by the high temperature of the cylinder section 61 and the exhaust pipe M. It should also be noted that, due to the above configuration, the return pipe 75 no longer has an upward riser section towards the motorcycle 2; thus, it can prevent airlocks from forming in the return pipe 75 when adding coolant to the radiator 72. In implementation of this invention, the distance between the radiator 72 and the cylinder bore centerline 61a of the cylinder section 61 is... The distance R1 is set to be greater than the distance R2 between the thermostat 616 and the cylinder bore centerline 61a of the cylinder section 61; in the vertical direction of the motorcycle 2, the outlet 6161 of the thermostat 616 is set higher than the top edge 6121 of the cylinder head 612, and the top edge of the hot liquid recovery port 72a of the radiator 72 is set higher than the top edge 6161a of the outlet 6161 of the thermostat 616; the water pump 614 and the thermostat 616 is installed on two opposite sides of the cylinder head 612; viewed from the front of the motorcycle 2, the cylinder head 612 is respectively located on two opposite sides of the inlet 6141 of the water pump 614 and the cylinder head 612 is respectively located on two opposite sides of the cylinder head 612; and the cylinder head 612 is configured to be higher than the cylinder head 612 is positioned above the cylinder head 612 is positioned above the cylinder head 612 is positioned above the cylinder head 612 is positioned above the cylinder head 612 is positioned above the cylinder head 612 is positioned above the cylinder head 612 is positioned above the cylinder head 612 is positioned above the cylinder head 612 is positioned above the cylinder head 612 is positioned above the cylinder head 612 is positioned above the cylinder head 614.

[0107] like Figure 3 , 4As shown in Figure 6, following the above description, with the aforementioned configuration, when viewed from the side of the motorcycle 2, the top edge 7511 of the bridging section 751 of the return pipe 75 is higher than one or both of the top edge 6121 of the cylinder head 612 of the cylinder section 61 and the top edge 6131 of the cylinder body 613 in the vertical direction of the motorcycle 2; when viewed from above the motorcycle 2, at least a portion of the bridging section 751 of the return pipe 75 is positioned closer to the rear of the motorcycle 2 than the outlet 6161 of the thermostat 616 and the hot liquid recovery port 72a of the radiator 72; when viewed from above the motorcycle 2, the return pipe 75... At least a portion of the bridging section 751 is located closer to the rear of the motorcycle 2 than one or both of the mating surface 63a of the cylinder section 61 and the crankcase 63 and the throttle body 93 of the intake system 9; viewed from above the motorcycle 2, at least a portion of the bridging section 751 of the return pipe 75 is located closer to the rear of the motorcycle 2 than the axis 6311 of the crankshaft 631; viewed from above the motorcycle 2, the bridging section 751 of the return pipe 75 is located in front of at least one or more of the following in the longitudinal direction of the motorcycle 2: the front edge of the muffler M1 of the exhaust pipe M, the rear edge of the radiator 72, and the front edge of the rear wheel RW.

[0108] The main feature of this invention is that the engine 6 of the motorcycle 2 includes at least a cylinder section 61 and a crankcase 63 connected to the cylinder section 61 and having a crankshaft 631, wherein the crankcase 63 and the cylinder section 61 have a mating surface 63a; the cylinder section 61 includes at least a cylinder head 612 and a cylinder body 613 connected to one end of the cylinder head 612; the cylinder section 61 has a cylinder bore centerline 61a, and the cylinder section 61 extends from the mating surface 63a along the cylinder bore centerline 61a. Extending forward towards the motorcycle 2, the cylinder head 612 contains a water jacket 615 for coolant flow; the engine 6 is equipped with a liquid cooling device 7 containing coolant and an intake system 9 that provides fresh air from outside. The liquid cooling device 7 includes at least a radiator 72 and a fan 71 located on one side of the radiator 72; the cylinder head 612 is equipped with a water pump 614 and a thermostat 616. The water pump 614 is connected to the radiator 72 via a coolant output pipe 74, and the thermostat 616 is connected to... The radiator 72 is connected by a return pipe 75; viewed from above the motorcycle 2, the inner edge 72b of the radiator 72 along the width direction of the motorcycle 2 is positioned further outward than the outer edge 71a of the fan 71; the return pipe 75 has a cross-connection section 751 that simultaneously spans the cylinder bore centerline 61a, the vehicle centerline 2a, and the left and right sides of the cylinder body 613 in the width direction; viewed from the side of the motorcycle 2, at least a portion of the radiator 72 is superimposed on the fan 71 and the crankshaft 63. 1; The jumper section 751 is configured to pass through the safety area A between the upper part of the crankcase 63 and the lower part of the intake system 9; thereby, it does not affect the use of space under the seat 4, and the jumper section 751 can be kept away from the high temperature cylinder head 612; at the same time, the height of the jumper section 751 can be increased to avoid damage from foreign objects on the ground; furthermore, the intake system 9 can perform heat dissipation on the jumper section 751 of the return pipe 75, and prevent air locks from forming in the return pipe 75.

[0109] In summary, the present invention, through the above-described structure, can improve upon known deficiencies and achieve the claimed purpose, and has indeed improved upon existing technologies, thus possessing novelty, practicality, and inventiveness.

Claims

1. A water-cooled engine structure for a motorcycle, characterized in that, The motorcycle engine includes at least a cylinder section and a crankcase with a crankshaft connected to the cylinder section, the crankcase and the cylinder section having a mating surface; the cylinder section includes at least a cylinder head and a cylinder body connected to one end of the cylinder head; the cylinder section has a cylinder bore centerline, the cylinder section extending along the cylinder bore centerline from the mating surface toward the front of the motorcycle, and the cylinder head has a water jacket for coolant flow; the engine is equipped with a liquid cooling device containing coolant and an intake system that provides fresh air from outside, the liquid cooling device including at least a radiator and a fan located on one side of the radiator; The cylinder head is equipped with a water pump and a thermostat. The water pump is connected to the radiator via a coolant output pipe, and the thermostat is connected to the radiator via a return pipe. Viewed from above by the motorcycle, the inner edge of the radiator along the width of the motorcycle is positioned further outward than the outer edge of the fan. The return pipe has a cross-section that simultaneously spans the cylinder bore centerline, the vehicle centerline, and the cylinder body on the left and right sides in the vehicle width direction. Viewed from the side by the motorcycle, at least a portion of the radiator overlaps the fan and the crankshaft. The cross-section is configured to pass through a safe area between the top of the crankcase and the bottom of the intake system.

2. The motorcycle water-cooled engine structure according to claim 1, characterized in that, Viewed from the side of the motorcycle, the top edge of the rear bridging section of the return pipe is higher than one or both of the top edge of the cylinder head of the cylinder section and the top edge of the cylinder body of the cylinder body in the vertical direction of the motorcycle.

3. The motorcycle water-cooled engine structure according to claim 1, characterized in that, Viewed from above by the motorcycle, at least a portion of the bridging section of the return pipe is positioned closer to the rear of the motorcycle than the outlet of the thermostat and the hot liquid recovery port of the radiator.

4. The motorcycle water-cooled engine structure according to claim 1, characterized in that, Viewed from above by the motorcycle, at least a portion of the bridging section of the return pipe is located closer to the rear of the motorcycle than one or both of the mating surfaces of the cylinder section and the crankcase and the throttle body of the intake system.

5. The motorcycle water-cooled engine structure according to claim 1, characterized in that, Viewed from the motorcycle, at least a portion of the bridging section of the return pipe is positioned closer to the rear of the motorcycle than the axis of the crankshaft.

6. The motorcycle water-cooled engine structure according to claim 1, characterized in that, The motorcycle has a rear wheel; viewed from above the motorcycle, the crossover section of the return pipe is disposed in front of at least one or more of the following in the longitudinal direction of the motorcycle: the front edge of the exhaust pipe's muffler, the rear edge of the radiator, and the front edge of the rear wheel.

7. The motorcycle water-cooled engine structure according to claim 1, characterized in that, In the width direction of the motorcycle, the distance between the radiator and the center line of the cylinder bore of the cylinder section is set to be greater than the distance between the thermostat and the center line of the cylinder bore of the cylinder section.

8. The motorcycle water-cooled engine structure according to claim 1, characterized in that, In the vertical direction of the motorcycle, the outlet of the thermostat is configured to be higher than the top edge of the cylinder head, and the top edge of the hot liquid recovery port of the radiator is configured to be higher than the top edge of the outlet of the thermostat.

9. The motorcycle water-cooled engine structure according to claim 1, characterized in that, In the vertical direction of the motorcycle, the outlet of the thermostat is configured to be higher than the inlet of the water pump.

Images