JP6572805B2 - Engine oil passage structure - Google Patents

Description

  The present invention relates to an oil passage structure for an engine capable of lubricating and cooling the engine using engine oil and performing knocking suppression control.

  Some motorcycle engines include an oil passage core structure for forming a head-side cooling oil passage in a cylinder head in which an ignition plug, an intake port, and an exhaust port are formed (see Patent Document 1). ). The oil passage core includes a first boss that forms an oil inflow passage, a second boss that forms an oil outflow passage, and an oil outflow passage that flows from the oil inflow passage around the spark plug and the exhaust port. And a cooling passage portion guided by the The cylinder head is cooled by the engine oil flowing in the head side cooling oil passage formed by the oil passage core.

JP2013-72354A

  In the engine described in Patent Document 1, the head side cooling oil passage formed in the cylinder head is divided into a cooling passage provided between the oil inflow passage and the oil outflow passage around the spark plug and the exhaust port. It is formed so that oil flows.

  Since engine oil has a lower specific heat than water, it is necessary to sufficiently increase the flow rate of the cooling oil in order to improve the cooling performance. However, in the oil passage structure of Patent Document 1, by increasing the oil inlet and the oil outlet, the flow passage cross-sectional area of the cooling passage is increased, and the oil flow rate is lowered, so that the cooling performance is lowered.

  Further, when the cooling passage is constituted only by the core, the cooling passage cross-sectional area depends on the minimum wall thickness that forms the core, so that the oil flow rate cannot be increased.

  Furthermore, in the oil passage structure of Patent Document 1, the intake side squish area of the combustion chamber is not sufficiently cooled, and there is a tendency that knocking tends to occur when the engine is under a high load or a high temperature.

  The present invention has been made in consideration of the above-described circumstances, and is an engine oil in which the squish area of the combustion chamber is sufficiently cooled to improve the knock limit, and knock suppression control is performed to prevent knocking. An object is to provide a passage structure.

  Another object of the present invention is to efficiently cool the intake-side squish area and the plug-in part squish area of the combustion chamber that is likely to cause knocking, lower the combustion chamber temperature, improve the intake charge efficiency, and increase the engine output. The object is to provide an improved oil passage structure for an engine.

  In order to solve the above-described problems, an oil passage structure of an engine according to the present invention includes a cylinder case in which a crankcase, a cylinder, and a valve mechanism are accommodated, and the oil passage in the cylinder head includes the cylinder head. An exhaust port cooling section that guides oil around the exhaust port provided in the cylinder and sends it back to the oil passage in the cylinder; and a combustion chamber cooling section that recirculates the oil flowing from the exhaust port cooling section to the periphery of the combustion chamber. An oil passage structure of an engine having an intake port cooling section provided between the combustion chamber cooling section and the intake port.

  In the oil passage structure of the engine according to the present invention, an intake port cooling portion is provided between the combustion chamber cooling portion guided around the combustion chamber and the intake port, so that oil cooling of the squish area portion of the combustion chamber is efficiently performed. This is often done to improve the knock limit, and knocking suppression control can prevent the occurrence of knocking.

  Further, the oil passage structure of the engine of the present invention cools the intake side squish area and the plug insertion part squish area of the combustion chamber, lowers the combustion chamber temperature, improves the intake charging efficiency, and improves the engine output. be able to.

1 is a left side view showing a motorcycle equipped with an engine to which an embodiment of an oil passage structure for an engine according to the present invention is applied. The front view which shows the engine of FIG. 1 with an oil cooler. The right view which shows the engine of FIG. 1 and FIG. The left view which shows the cylinder assembly which comprises an engine. 4 is a system diagram showing an oil passage structure of the engine in FIGS. The top view of the cylinder which comprises a cylinder assembly. The figure which looked up at the cylinder head which comprises a cylinder assembly from the downward direction. The top view of the state which removed the cover member from the cylinder head shown in FIG. The perspective view which shows the oil jacket structure provided in the cylinder and cylinder head of a cylinder assembly. The perspective view which looked at the oil jacket structure shown in FIG. 9 from the exhaust port side. FIG. 10 is a perspective view of the oil jacket structure shown in FIG. 9 as viewed from the left side of the motorcycle. Sectional drawing which follows the XII-XII line | wire of FIG. The top view which shows the oil jacket structure of FIG. FIG. 14 is a side view of the oil jacket structure shown in FIG. 13 as viewed from the left side of the motorcycle. The side view which looked at the oil jacket structure shown by FIG. 9 from the intake port side. The side view which looked at the oil jacket structure shown by FIG. 9 from the exhaust port side.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

  FIG. 1 is a left side view of a motorcycle equipped with an engine to which an embodiment of an oil passage structure for an engine according to the present invention is applied. FIG. 2 is a front view showing the engine of FIG. 1 together with an oil cooler, and FIG. 3 is a left side view showing the engine of the motorcycle. In the present embodiment, front and rear and left and right expressions are based on the driver at the time of boarding the vehicle.

  A motorcycle 10 shown in FIG. 1 has a vehicle body frame 11 having a head pipe 12 at a front end portion. The vehicle body frame 11 is a so-called cradle frame, and includes a head pipe 12, a main tube 13, a down tube 14, and a pair of left and right seat rails 15.

  A steering mechanism 16 is pivotally supported on the head pipe 12 positioned above the front portion of the vehicle body frame 11. A front fork 17 and a handle bar 18 that rotatably support a front wheel 19 and incorporate a suspension mechanism are attached to the steering mechanism 16. The front wheel 19 is steered left and right using the handlebar 18. A front fender 20 is fixed to the front fork 17 so as to cover the upper part of the front wheel 19.

  The main tube 13 extends obliquely rearward and downward from the upper rear surface of the head pipe 12 and is curved and extends downward from the vehicle. A lower end portion of the main tube 13 is coupled to a pivot bracket (not shown). Further, the down tube 14 extends from the lower rear surface of the head pipe 12 to the vehicle lower side, is curved and extends rearward of the vehicle, and the rear end portion is coupled to the pivot bracket. The pivot bracket is provided with a pivot shaft support (not shown), and the swing arm 23 is pivotally supported on the pivot shaft support so as to be swingable in the vehicle vertical direction. A rear wheel 24 is rotatably supported at the rear end of the swing arm 23.

  A pair of left and right seat rails 15 are coupled to the main tube 13 and extend rearward of the vehicle. The pair of left and right seat rails 15 are connected and reinforced by a plurality of frame bridges (not shown) sequentially arranged in the vehicle longitudinal direction. These seat rails 15 are supported by the pivot bracket via a pair of left and right seat pillars 25. A rear fender 26 that covers the upper portion of the rear wheel 24 is supported on the seat rail 15. In addition, a rear cushion unit 27 is loaded between the seat rail 15, the seat pillar 25, and the swing arm 23, and shock loads from the rear wheels 24 are buffered.

  A fuel tank 28 is supported on the main tube 13 at a position behind the head pipe 12. A seat 29 is supported by the seat rail 15 adjacent to the rear of the fuel tank 28.

  On the other hand, a front cover 32 that covers the upper front of the vehicle is installed on the steering mechanism 16 or the front fork 17, and a headlight 33 and the like are disposed on the front cover 32. In addition, a pair of left and right side covers 34 are attached to the main tube 13 and the seat rail 15 to cover regions below the rear part of the fuel tank 28 and below the front part of the seat 27. Further, a rear cover 35 is attached to the seat rail 15 so as to cover an area below the rear portion of the seat 27 above the rear wheel 24.

  Further, an engine 38 is mounted between the main tube 13 and the down tube 14. The engine 38 is a four-cycle single cylinder engine, for example, and is positioned below the fuel tank 28. The engine 38 drives the rear wheel 24 via a drive chain 39 wound around the rear wheel 24.

  The engine 38 is configured as shown in FIGS. 2 to 4, and includes a crankcase 40 and a cylinder assembly 41 coupled to a front portion of the upper surface of the crankcase 40. The cylinder assembly 41 includes a cylinder 42, a cylinder head 43 that closes the top of the cylinder 42, and a head cover 44 that closes the top of the cylinder head 43. A carburetor (or a throttle body) (not shown) constituting an engine intake system, an air cleaner, and the like are sequentially connected to the rear portion of the cylinder head 43. Further, an exhaust pipe (not shown) and an exhaust muffler that are engine exhaust systems are sequentially connected to the front portion of the cylinder head 43.

  As shown in FIG. 2, the crankcase 40 includes a left half 40A and a right half 40B coupled to each other at a coupling surface 40C. The left half 40A has a magnet cover 45 and the right half 40B has a clutch. Each cover 46 is provided. A crankshaft 47 shown in FIG. 3 is rotatably supported in the crank chamber of the crankcase 40. A transmission chamber 48 is formed in the crankcase 40 adjacent to the crank chamber. A transmission (T / M) 51 including a counter shaft and a drive shaft 50 (both shown in FIG. 5) is accommodated in the mission chamber 48. An oil pan 52 for storing engine oil is provided at the lower part of the crankcase 40.

  The cylinder assembly 41 is coupled to the crankcase 40 in a slightly forward inclined posture. As shown in FIG. 6, a cylindrical cylinder bore 53 is formed in the cylinder 42 constituting the cylinder assembly 41. A piston 54 connected to the crankshaft 47 via a connecting rod (not shown) is disposed in the cylinder bore 53 so as to be capable of reciprocating. Further, as shown in FIG. 6, a cam chain chamber 55 is formed in the cylinder 42 adjacent to the cylinder bore 53.

  The cylinder head 43 shown in FIGS. 2 and 3 is coupled to the top of the cylinder 42 and closes the cylinder bore 53 to form a combustion chamber 56 with the piston 54. As the air-fuel mixture burns in the combustion chamber 56, the piston 54 reciprocates. Further, the cylinder head 43 is provided with a pair of intake ports 57 for supplying air-fuel mixture into the combustion chamber 56 on the back wall side, and a pair for discharging the combustion gas generated in the combustion chamber 56 on the front wall side. The exhaust port 58 is provided.

  3 and FIGS. 6 to 8, the cylinder head 43 is driven to drive a pair of intake valves 59 for opening and closing the intake port 57 and a pair of exhaust valves 60 for opening and closing the exhaust port 58. The valve mechanism 61 is accommodated between the head cover 44. The camshaft of the valve mechanism 61 is driven between the crankshaft 47 and a cam chain (not shown). This cam chain is disposed in the cam chain chamber 55 of the cylinder 42 and the cam chain chamber 63 of the cylinder head 43.

  Also, bolt holes 64 are formed at four locations around the cylinder bore 53 and the combustion chamber 56 in the cylinder 42 and the cylinder head 43, respectively, as shown in FIGS. By inserting stud bolts into these bolt holes 64, the cylinder 42 and the cylinder head 43 are coupled to the crankcase 40.

  2 and 5, the engine 38 has an oil passage structure 65. The oil passage structure 65 includes a crankcase side oil passage 66, a cylinder side oil passage 67, and a cylinder head side oil passage 68. It is prepared for.

  The crankcase-side oil passage 66 is an oil passage provided in the crankcase 40, and supplies and lubricates the engine oil to the respective lubrication portions in the crankcase 40 and the cylinder 42. The cylinder-side oil passage 67 is an oil passage provided in the cylinder 42 and cools the periphery of the combustion chamber 56 with engine oil. Further, the cylinder head side oil passage 68 is an oil passage provided in the cylinder head 43, and lubricates the valve operating mechanism 61 with engine oil and mainly cools the periphery of the exhaust port 58.

  As shown in FIGS. 2 and 5, the crankcase-side oil passage 66 is connected to a first oil passage portion 69, an oil pump 70, a second oil passage portion 71, an oil filter 72, and a third oil passage portion 73 in order. In addition, a fourth oil passage 74 is connected to the oil filter 72.

  The first oil passage portion 69 is connected to the oil pan 52 directly or via an oil strainer (not shown). The oil pump 70 is a mechanical oil pump that is driven by an auxiliary machine drive gear (not shown) that is integrally rotated with the crankshaft 47. Therefore, the output of the oil pump 70 depends on the rotational speed of the crankshaft 47 (that is, the rotational speed of the engine 38), and a larger amount of engine oil is discharged as the rotational speed of the crankshaft 47 becomes higher.

  When the oil pump 70 is operated, the engine oil in the oil pan 52 is discharged from the oil pump 70 through the first oil passage portion 69 directly or after the foreign matter is removed by the oil strainer. Then, it flows into the oil filter 72, and foreign matters in the engine oil are removed.

  The engine oil from which foreign matter has been removed by the oil filter 72 passes through the third oil passage portion 73, and each piston of the engine 38 slides in the lubricating portions of the engine 38, that is, the crankshaft 47 in the crank chamber and the cylinder bore 53 of the cylinder 42. 54, supplied to the transmission 51 in the transmission chamber 48, etc., and lubricates the crankshaft 47, piston 54, and transmission 51 (including the counter gear or shaft 49 and the drive gear or shaft 50). Further, the fourth oil passage portion 74 is connected to the fifth oil passage portion 75 of the cylinder side oil passage 67.

  As shown in FIGS. 2 and 5, the cylinder-side oil passage 67 includes a fifth oil passage portion 75 and a sixth oil passage portion 76 that communicate with each other, and oil that is connected to the oil cooler 80 from the fifth oil passage portion 75. A cooler inflow side oil hose 81 and a tenth oil passage portion 85 and a thirteenth oil passage portion 88 communicating with each other are provided. The tenth oil passage portion 85 constitutes a combustion chamber cooling portion that cools the combustion chamber 56 of the cylinder 42, and is an oil jacket described later.

  The cylinder head side oil passage 68 of the cylinder assembly 41 communicates with the cylinder side oil passage 67 and is connected to a seventh oil passage portion 77 for cooling the valve operating mechanism 61 and an oil cooler outflow side oil hose 82. The eighth oil passage 83, the ninth oil passage 84 of the exhaust port cooling portion communicating with the eighth oil passage 83, the eleventh oil passage 86 of the intake port cooling portion, and the spark plug insertion portion cooling Part of the twelfth oil passage 87.

  The ninth oil passage portion 84 is an oil jacket that bypasses the portion around the exhaust port 58 and constitutes an exhaust port cooling portion. The eleventh oil passage portion 86 and the twelfth oil passage portion 87 communicate with both sides of the first separation portion 90a and the second separation portion 90b of the tenth oil passage portion 85, respectively. The eleventh oil passage portion 86 is an oil jacket constituting an intake port cooling portion, and the twelfth oil passage portion 87 is an oil jacket constituting a spark plug insertion portion cooling portion.

  The oil guided from the oil cooler outflow side oil hose 82 to the exhaust port cooling portion of the ninth oil passage portion 84 through the eighth oil passage portion 83 cools around the exhaust port 58, and The oil is guided to the upstream side of the 10 oil passage portion 85, and the combustion chamber cooling portion is cooled by the tenth oil passage portion 85.

  Further, the oil guided to the tenth oil passage portion 85 is guided from the first dividing portion 90a to the eleventh oil passage portion 86 of the cylinder head side oil passage 68, where the intake port cooling portion is cooled. The oil that has cooled the intake port cooling portion through the eleventh oil passage portion 86 is returned to an intermediate portion of the tenth oil passage portion 85 to cool the combustion chamber 56, and then the cylinder head side oil from the second partition portion 90b. Guided by the twelfth oil passage portion 87 of the passage 68, the twelfth oil passage portion 87 is cooled around the spark plug insertion portion 91. The oil that has cooled the spark plug insertion portion cooling portion by the twelfth oil passage portion 87 is returned to the downstream side of the tenth oil passage portion 85 of the cylinder side oil passage 67 again, and from the downstream end of the tenth oil passage portion 85. After passing through the thirteenth oil passage portion 88, it passes through the return side of the crankcase side oil passage 66 and is returned to the oil pan 52.

  On the other hand, as shown in FIGS. 2, 5, and 6, the fifth oil passage portion 75 of the cylinder-side oil passage 67 is formed to extend linearly in the horizontal direction below the front wall of the cylinder 42. . Part of the engine oil that has flowed into the fifth oil passage portion 75 reaches the seventh oil passage portion 77 of the cylinder head side oil passage 68 via the sixth oil passage portion 76, and this seventh oil passage portion. The valve operating mechanism 61 is guided from 77 to a valve operating mechanism 61 (particularly a camshaft) to lubricate the valve operating mechanism 61.

  Here, the sixth oil passage portion 76 intersects the fifth oil passage portion 75 of the cylinder-side oil passage 67 at right angles and extends upward to be formed in the cylinder 42. The seventh oil passage portion 77 of the cylinder head side oil passage 68 communicates with the sixth oil passage portion 76 of the cylinder side oil passage 67 shown in FIG. 6 and extends in the substantially vertical direction to the cylinder head 43. In the vicinity of the camshaft of the valve mechanism 61.

  As shown in FIGS. 2 and 6, the remainder of the engine oil that has flowed into the fifth oil passage portion 75 of the cylinder side oil passage 67 is sent to the oil cooler 80 via the inflow side oil hose 81 to be cooled. . As shown in FIGS. 1 and 2, the oil cooler 80 is disposed obliquely in front of the engine 38 in the down tube 14 of the vehicle body frame 11. In particular, the oil cooler 80 is preferably arranged so as to avoid being exposed to the front wheels 19 and the front fender 20 so as to be easily exposed to the traveling wind of the motorcycle 10. A cooling fan that generates cooling air is disposed on the back of the oil cooler 80. Therefore, the oil cooler 80 actively cools the inflowing engine oil by exchanging heat with the cooling air from the cooling fan and the traveling air of the motorcycle 10.

  The engine oil cooled by the oil cooler 80 flows into the eighth oil passage portion 83 of the cylinder head side oil passage 68 via the outflow side oil hose 82, as shown in FIGS. It flows from the portion 83 into the ninth oil passage portion 84 constituting the exhaust port cooling portion.

  As shown in FIGS. 2, 4, and 5, the eighth oil passage portion 83 is formed at a corner of the front wall of the cylinder head 43 with the left side wall. Further, as will be described in detail later, the ninth oil passage portion 84 is formed substantially around the exhaust port 58 in the cylinder head 43, and the engine oil from the eighth oil passage portion 83 is passed around the exhaust port 58 of the cylinder head 43. Then, the periphery of the exhaust port 58 is cooled.

  The engine oil that has flowed through the ninth oil passage portion 84 then flows into the inlet 85 a of the tenth oil passage portion 85 of the cylinder side oil passage 67 as shown in FIGS. 5 and 6. The tenth oil passage portion 85 is formed around the cylinder bore 53 at the joint surface of the cylinder 42 with the cylinder head 43, and the engine oil from the ninth oil passage portion 84 of the cylinder head side oil passage 68 is substantially omitted as a whole. The periphery of the combustion chamber 56 is cooled by flowing in an annular shape. The engine oil cooled around the combustion chamber 56 is cranked from the outlet port 85b of the tenth oil passage portion 85 through the thirteenth oil passage portion 88 of the cylinder side oil passage 67 as shown in FIGS. The oil pan 52 in the case 40 is returned. The thirteenth oil passage 88 is formed in a vertical direction at a corner of the front wall of the cylinder 42 with the left front wall. A gasket 92 is interposed between the joint surfaces of the cylinder 42 and the cylinder head 43, and the gasket 92 is joined to a liquid-tight structure to improve the sealing performance.

  As will be described in detail later, the engine oil cooled by the oil cooler 80 is returned to the ninth oil passage portion 84 through the eighth oil passage portion 83 of the cylinder head side oil passage 68 shown in FIGS. The area around the 43 exhaust ports 58 is cooled. The ninth oil passage portion 84 constitutes an oil jacket that forms an exhaust port cooling portion.

  The engine oil that has passed through the ninth oil passage portion 84 and has cooled the exhaust port cooling portion is subsequently guided to the tenth oil passage portion 85 of the cylinder side oil passage 67 as shown in FIGS. The periphery of the combustion chamber 56 of the cylinder 42 is cooled by the tenth oil passage portion 85. The tenth oil passage portion 85 constitutes an oil jacket that cools the combustion chamber 56.

  The tenth oil passage portion 85 is formed in a substantially annular shape as a whole, and two separation portions 90a and 90b are configured as shown in FIG. As shown in FIGS. 5 and 7, the partition portions 90 a and 90 b communicate with the eleventh oil passage portion 86 and the twelfth oil passage portion 87 of the cylinder head side oil passage 68, as shown in FIGS. 5 and 7. The eleventh oil passage portion 86 forms an intake port cooling portion, and the twelfth oil passage portion 87 forms an ignition plug insertion portion cooling portion to constitute an oil jacket.

[Cylinder and cylinder head oil jacket structure]
As shown in FIGS. 6 to 9, the cylinder 42 and the cylinder head 43 of the cylinder assembly 41 are configured in an oil jacket structure with a cooling oil passage. The cooling oil passages of the cylinder 42 and the cylinder head 43 are formed in an oil passage core structure.

  The head side cooling oil passage of the cylinder head 43 is guided from the outflow side oil hose 82 of the oil cooler 80 to the ninth oil passage portion 84 through the eighth oil passage portion 83 of the cylinder head side oil passage 68. The ninth oil passage portion 84 is guided around the exhaust port 58 and has an upper flow passage portion 96 formed by the upper core 95 and a lower flow passage portion 98 formed by the lower core 97. . The engine oil that has flowed into the inlet portion 84a of the ninth oil passage portion 84 is guided from the inlet portion 84a to the upper flow passage portion 96 through between the branch portions of the exhaust port 58, and the upper flow passage portion 96 is zigzag-shaped. Meander to the lower flow path 98. In the lower flow path portion 98, engine oil is guided to the outlet portion 94 b through the outer side of the branch portion of the exhaust port 58. In the ninth oil passage portion 84, the engine oil cooled from the oil cooler 80 flows around the exhaust port 58, and constitutes an oil jacket of the exhaust port cooling portion.

  In the oil jacket structure shown in FIGS. 7 to 11, engine oil flowing around the exhaust port 58 in the cylinder head 43 flows through the ninth oil passage portion 84 from the inlet portion 84a to the upper flow passage portion 96 and the lower flow portion. Although the example in which the passage 98 is sequentially guided to the outlet 94b is shown, the engine oil is guided around the exhaust port 58 from the lower passage 98 to the upper passage 96. May be.

  Incidentally, the upper channel portion 96 of the ninth oil passage portion 84 shown in FIGS. 8 to 11 is configured as shown in FIG. 8 in plan view. An open portion that is provided on the top surface of the cylinder head 43 and that opens upward is formed by the upper core 95, and a lid member 100 (see FIG. 8) that covers the open portion from above is provided so that the upper flow path portion 96 is formed. Composed.

  The open part of the upper flow path part 96 is an area above the exhaust port 58 and below the valve operating mechanism 61, and is formed between the intake valve 59 and the exhaust valve 60 arranged in pairs. The open portion of the upper flow passage portion 96 communicates with the inlet portion 84a from the eighth oil passage portion 83 at the upstream end, and the tenth oil passage through the outlet portion 84b of the lower flow passage portion 98 at the downstream end. Communicating with the inlet 85 a from the portion 85. Further, the open portion is formed to meander in a zigzag shape, and the flow path length becomes longer than that in the case of a straight line shape, and the heat exchange efficiency of the engine oil flowing inside is increased.

  Furthermore, as shown in FIGS. 9 to 11, the upper core 95 that forms the open portion of the upper flow path portion 96 has a depression formed on the outer surface. By this depression, a channel wall surface extending in the channel direction is formed in the open portion.

  As shown in FIG. 12, the lid member 100 of the upper flow passage portion 96 covers the open portion of the upper flow passage portion 96 from above, and a protrusion 101 corresponding to the shape of the upper flow passage portion 96 of the open portion. Is formed to protrude. When the protrusion 101 of the lid member 100 is inserted into and engaged with the flow path of the open portion, the gap between the protrusion 101 and the open portion is configured as the upper flow path portion 96 of the ninth oil passage portion 84. .

  Further, as shown in FIG. 12, the lid member 100 is coupled to the cylinder head 43 using the mounting bolts 102 in a state where the joint surface 101 a of the lid member 100 and the joint surface 96 a of the open portion are joined. At this time, one of the joint surface 101a of the lid member 100 and the joint surface 96a of the open part (for example, the joint surface 101a of the lid member 100) is formed on a non-machined surface that is not flattened, that is, a casting surface. Has been. Thereby, gas, such as air bubbles, is configured to pass through the gap between the joint surface 101a of the lid member 100 and the joint surface 96a of the open portion. In addition, the code | symbol 103 in FIG. 8 shows the position of the cam housing which accommodates the valve operating mechanism 61. FIG.

  As shown in FIGS. 5, 10, and 11, the outlet portion 84 b of the ninth oil passage portion 84 communicates with the tenth oil passage portion 85 of the cylinder-side oil passage 67 and downwards to the left side of the exhaust port 58. Inclined and processed. The downstream end of the lower flow path portion 98 communicates with the tenth oil passage portion 85 of the cylinder side oil passage 67. As described above, the engine oil flows in the ninth oil passage portion 84 mainly constituted by the upper flow passage portion 96 and the lower flow passage portion 98, so that the periphery of the exhaust port 58 in the cylinder head 43 is cooled. Is done.

  As shown in FIGS. 5 and 9 to 11, the tenth oil passage portion 85 is formed in a substantially annular shape around the cylinder bore 53 (combustion chamber 56) on the joint surface of the cylinder 42 with the cylinder head 43. The annular groove 105 and a gasket 93 (FIG. 7) sandwiched between the cylinder 42 and the cylinder head 43 are defined. The annular groove 105 is an inflow port portion 85 a corresponding to the lower region of the exhaust port 58 of the cylinder head 43, and communicates with the outflow port portion 84 b of the ninth oil passage portion 84 of the cylinder head 43, and the cylinder bore 53 (combustion chamber 56). , And the outflow port portion 85 b communicates with the thirteenth oil passage portion 88 of the cylinder side oil passage 67.

  The annular groove 105 is also formed by a ring-shaped core (not shown). The ring-shaped core is formed with a plurality of recesses along the inner peripheral surface and the outer peripheral surface. A plurality of protrusions are formed at 105. The engine oil flows in the tenth oil passage portion 85 (particularly the annular groove 105) configured as described above, thereby constituting an oil jacket for the combustion chamber cooling portion, and the combustion chambers in the cylinder 42 and the cylinder head 43. The area around 56 is cooled.

  Incidentally, in the oil jacket structure of the cylinder 42 shown in FIG. 6, the annular groove 105 of the tenth oil passage portion 85 is divided into three arc-shaped portions 105a and 105b by two separating portions 90a and 90b spaced in the circumferential direction. , 105c. The oil jacket of the tenth oil passage portion 85 is lifted from the cylinder 42 side to the cylinder head 43 side, and the oil jacket is partitioned by the first and second partition portions 90a and 90b. The ribs of the two separation portions 90a and 90b of the tenth oil passage portion 85 improve the bore rigidity of the open deck cylinder. Like the closed cylinder, the cylinder 42 is less likely to be deformed even when subjected to piston side pressure.

  Further, as shown in FIGS. 5 and 6, the tenth oil passage portion 85 constituting the combustion chamber cooling portion communicates with the eleventh oil passage portion 86 of the cylinder head side oil passage 68 at the first dividing portion 90 a. And communicated with the twelfth oil passage portion 87 at the second partitioning portion 90b. An oil temperature sensor 108 that measures the oil temperature in the oil jacket that flows through the cylinder 42 is installed in the tenth oil passage portion 85.

  Specifically, the annular groove 105 of the tenth oil passage portion 85 is communicated with the eleventh oil passage portion 86 of the cylinder head side oil passage 68 from the downstream end of the first arcuate portion 105a. Engine oil is supplied to the intake port 57 to cool the side of the branch portion. The engine oil that has cooled the intake port cooling portion of the eleventh oil passage portion 86 is returned to the upstream end of the second arc-shaped portion 105b of the annular groove 105 of the tenth oil passage portion 85 through the outlet.

  The engine oil returned to the second arcuate portion 105b of the annular groove 105 is sent to the twelfth oil passage portion 87 of the cylinder head side oil passage 68 from the downstream end after cooling the second arcuate portion 105b. The twelfth oil passage portion 87 cools the vicinity of the spark plug insertion portion 91. The twelfth oil passage portion 87 constitutes a spark plug insertion portion cooling portion, and the engine oil that has passed through the twelfth oil passage portion 87 is the third arc-shaped portion of the tenth oil passage portion 85 from its downstream end. 105c is returned to the upstream end.

  The engine oil returned to the third arc-shaped portion 105c of the tenth oil passage portion 85 cools the third arc-shaped portion 105c, and then returns to the thirteenth oil passage portion 88 from the outlet port 85b. The oil is returned from the side oil passage 67 to the oil pan 52 through the crankcase side oil passage 66.

[Cylinder and cylinder head]
As shown in FIGS. 6 and 7, the cylinder head 43 constituting the cylinder assembly 41 is formed with an intake port 57, an exhaust port 58, and a spark plug insertion portion 91. As shown in FIG. 12, an oil passage core structure for forming a head side cooling oil passage is disclosed. The cooling oil passage of the cylinder head 43 is formed of a sand core to form an oil jacket. The ninth oil passage portion 84 that forms the exhaust port cooling portion and the eleventh oil that forms the intake port cooling portion. It has a passage portion 86 and a twelfth oil passage portion 87 that forms a spark plug insertion portion cooling portion. As shown in FIG. 4, the spark plug 110 is inserted into the spark plug insertion portion 91 of the cylinder head 43 obliquely from the left side.

  By the way, as shown in FIG. 6, the periphery of the combustion chamber 56 of the cylinder 41 is cooled by engine oil passing through the tenth oil passage portion 85 of the combustion chamber cooling portion. The combustion chamber surface of the cylinder head 43 that forms the ceiling surface of the combustion chamber 56 is engine oil that passes through the head side cooling oil passages (the ninth oil passage portion 84, the eleventh oil passage portion 86, and the twelfth oil passage portion 87). Cooled by. Thus, the combustion chamber 56 formed in the cylinder 42 and the cylinder head 43 is lubricated and cooled by the engine oil passing through the ninth to twelfth oil passage portions 84 to 87.

In general, when the temperature of the engine 38 becomes high, the cylinder 42 or the cylinder head 43 may be thermally deformed, or when the temperature in the combustion chamber 56 becomes high, knocking may occur and abnormal combustion may occur. The place where knocking is likely to occur is
1. The part that is far from the spark plug 110 and difficult to propagate the flame,
2. Parts with high ambient temperature,
3. The part where unburned gas tends to accumulate,
It is.

  For example, as shown in FIG. 7, the fuel adhering to the intake port 57 does not volatilize in the intake side squish area 112 of the cylinder head 43, and it easily flows into the unburned gas and is knocked. The spark plug 110 is inserted obliquely downward from the left side into the spark plug insertion portion 91 as shown in FIGS. 4, 5, and 7, but the plug insertion side squish area 113 is also far from the spark plug 110, It is a part where flame propagation is difficult and knocking is likely to occur.

  In the present embodiment, the cylinder head 43 corresponding to the intake side squish area 112 and the plug insertion side squish area 113 in FIG. 7 is provided with an eleventh oil passage portion 86 near the branch portion of the intake port 57, and an ignition plug. The twelfth oil passage portions 87 are respectively installed in the vicinity of the insertion portion 91. The eleventh oil passage portion 86 constitutes an intake port cooling portion, and the twelfth oil passage portion 87 constitutes a spark plug insertion portion cooling portion.

  In the engine 38 of the motorcycle 10, the traveling wind W hits the front (exhaust port 58) side of the cylinder 41 and is cooled, as shown in FIG. The rear side of the cylinder 41 (intake port 57) is not hit by wind, and is stagnated, so there is no cooling by the running wind W and the temperature tends to increase. Knocking is likely to occur on the rear side of the cylinder 41 due to the high atmospheric temperature. In order to avoid this knocking, in the conventional air-cooled engine, an air temperature sensor is arranged at the upper part on the rear side of the cylinder, and a correlation map between the cylinder temperature and the occurrence of knocking is created so that the knocking does not occur when the cylinder temperature exceeds a certain level. Furthermore, ignition control is performed to prevent the occurrence of abnormal combustion.

  However, in the present embodiment, as shown in FIG. 7, the eleventh oil passage portion 86 of the intake port cooling portion is connected to the cylinder head 43 corresponding to the intake side squish area 112 and the plug insertion side squish area 113 where knocking is likely to occur. And the 12th oil passage part 87 of a spark plug insertion part cooling part is installed. The eleventh oil passage portion 86 and the twelfth oil passage portion 87 are sand jacket oil jackets disposed to face the intake side squish area 112 and the plug insertion side squish area 113. This oil jacket can reduce the temperature of the squish areas 112 and 113 where knocking is likely to occur, improve the knock limit, and suppress the occurrence of knocking by knocking suppression control. Thereby, a combustion chamber temperature can be reduced, fuel filling efficiency can be improved, and engine output can be improved.

  In the case of a water-cooled engine, in the water jacket structure that enters the cylinder head side from the cylinder side and returns to the cylinder again, bubbles accumulate in the passage and the combustion chamber 56 may become locally hot, thereby suppressing the occurrence of knocking. Difficult to do.

  However, as in the present embodiment, in the oil jacket structure, a cooling oil passage (tenth oil passage portion 85 to twelfth oil passage portion 87) structure that enters the cylinder head 43 side from the cylinder 42 side and returns to the cylinder 42 side again. However, since the bubbles are pushed out by the viscosity of the oil, the bubbles do not accumulate in a part of the oil passage, and the combustion chamber 56 can be prevented from being locally heated.

  Therefore, the oil jacket structure shown in FIGS. 9 to 16 is a cooling oil passage structure characteristic for oil cooling. In the present embodiment, the oil jacket structure is a cooling oil passage structure (a tenth oil passage portion 85 to a twelfth oil passage portion 87) that enters the cylinder head 43 side from the cylinder 42 side and returns to the cylinder 42 side again. However, various variations of the oil jacket structure are possible. For example, after the exhaust port cooling part is cooled by the ninth oil passage part 84 in the cylinder head 43, the eleventh oil passage part 86 of the intake port cooling part and the twelfth oil passage part 87 of the spark plug insertion part cooling part are changed. After cooling with engine oil, the engine oil may be guided to the tenth oil passage portion 85 and guided around the combustion chamber 56 to cool the combustion chamber cooling portion.

  When the oil jacket structure shown in FIGS. 9 to 16 is provided, the oil jacket facing the intake side squish area 112 shown in FIG. 7 in particular is configured as shown in FIG. Etc., the temperature distribution of the engine oil becomes uniform. For this reason, the linearity of the temperature rise of the cylinder 42 upper part after engine starting and the oil temperature rise of engine oil improves. As a result, the knocking suppression ignition control by the oil temperature feedback can be performed by measuring the oil temperature by the oil temperature sensor 108 without providing the machine temperature sensor.

  In the engine oil passage structure according to the present embodiment, an oil jacket is installed in the cylinder 42 and the cylinder head 43. The oil jacket of the cylinder 42 is a portion that is lifted from the cylinder 42 side to the cylinder head 43 side, and two separation portions 90a and 90b are provided in the annular groove 105 in a rib shape. The rib-shaped separation portions 90a and 90b formed in the annular groove 105 of the cylinder 42 can improve the bore rigidity of the open deck cylinder 42, and the cylinder 42 can apply the piston 54 side pressure to the open deck as well as the closed deck. This makes it difficult to deform and improves the seal durability of the head gasket 93 and improves the roundness of the bore of the cylinder bore.

  Further, the cylinder head 43 includes an intake port cooling portion and a plug insertion portion of an oil jacket formed of a sand core in a portion facing the intake side squish area 112 and the plug insertion side squish area 113 where knocking is likely to occur. Install a cooling unit. By the eleventh oil passage portion 86 of the intake port cooling portion and the twelfth oil passage portion 87 of the plug insertion portion cooling portion, the temperature of the squish area portion where knocking easily occurs can be reduced and the knock limit can be improved. In addition, the intake charging efficiency can be improved by lowering the combustion chamber temperature, and the engine output can be improved.

  Further, if the oil temperature sensor 108 is arranged upstream of the oil jacket (the eleventh oil passage portion 86) in the intake side squish area 112, the pressure loss of the oil passage in the intake side squish area 112 is large, and the flow rate of engine oil is low. In this case, the oil stays, so that the oil temperature and the cylinder temperature tend to approximate to improve the controllability. In addition, if an oil jacket is installed in the cylinder head 43 so as to face the upper part of the intake side squish area 112 or the upper part of the plug insertion side squish area 113, the number of oil jackets is increased and the heat exchange area is increased. The cooling efficiency of 56 itself can be improved.

[Effect of the embodiment]
In the oil passage structure of the engine according to the present embodiment, the knock limit can be improved by cooling the squish area portion where knocking is likely to occur. By reducing the combustion chamber temperature, intake charge efficiency can be improved and engine output can be improved.

  By forming two separators in the annular groove of the oil jacket formed around the combustion chamber of the cylinder, the separators can be ribbed to improve cylinder bore rigidity, and thermal deformation due to piston side pressure Can be suppressed. Further, since the bore rigidity of the cylinder 42 is improved, the durability of the head gasket is improved and the roundness of the bore can be improved.

  Furthermore, by arranging the oil temperature sensor 108 in the oil passage of the intake port cooling unit facing the intake side squish area of the combustion chamber, the flow velocity of the engine oil is reduced in the intake port cooling unit, and the temperature distribution becomes uniform. As a result, the linearity between the rise in the upper temperature of the cylinder 42 and the rise in the oil temperature is improved, and control is possible at the knocking suppression point due to the oil temperature, and the machine temperature sensor used for knocking control can be eliminated.

  As mentioned above, although embodiment of this invention was described, this embodiment is shown as an example and is not intending limiting the range of invention. This embodiment can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention.

  For example, as shown in FIGS. 9 to 11, the open portion of the upper flow passage portion 96 of the ninth oil passage portion 84 is formed by the upper core 95 and the lower flow passage portion 98 is formed by the lower core 97. The case where the annular groove 105 of the oil passage portion 85 is formed by a substantially ring-shaped core has been described, but the upper flow passage portion 96, the lower flow passage portion 98, the annular groove 105 and the eleventh oil passage portion. 86 and the twelfth oil passage 87 may be formed by machining without the core.

  Moreover, in order to increase a heat exchange area, you may form a fine protrusion part and a hollow part in the surface of the protrusion 101 (FIG. 12) of the cover member 100 which comprises the upper flow path part 96. FIG. Further, the oil cooler 80 shown in FIGS. 1 to 3 may be eliminated if the engine 38 is small and the cooling performance of the engine 38 is ensured even if the oil cooler 80 is eliminated.

  DESCRIPTION OF SYMBOLS 10 ... Motorcycle, 11 ... Body frame, 12 ... Head pipe, 13 ... Main tube, 14 ... Down tube, 15 ... Seat rail, 16 ... Steering mechanism, 17 ... Front fork, 18 ... Handlebar, 19 ... Front wheel, 20 ... front fender, 23 ... swing arm, 24 ... rear wheel, 25 ... seat pillar, 26 ... rear fender, 27 ... rear cushion unit, 28 ... fuel tank, 29 ... seat, 32 ... front cover, 33 ... headlight, 34 ... Side cover 35 ... Rear cover 38 ... Engine 39 ... Drive chain 40 ... Crank case 41 ... Cylinder assembly 42 ... Cylinder 43 ... Cylinder head 44 ... Head cover 45 ... Magnet cover 46 ... Clutch cover 47 ... Crankshaft, 48 ... , 50 ... Drive shaft, 51 ... Transmission, 52 ... Oil pan, 53 ... Cylinder bore, 54 ... Piston, 55 ... (Cylinder) cam chain chamber, 56 ... Combustion chamber, 57 ... Intake port, 58 ... exhaust port, 59 ... intake valve, 60 ... exhaust valve, 61 ... valve operating mechanism, 62 ... camshaft, 63 ... cam chain chamber (of the cylinder head), 64 ... bolt hole, 65 ... oil passage structure, 66 ... Crankcase side oil passage, 67 ... Cylinder side oil passage, 68 ... Cylinder head side oil passage, 69 ... First oil passage, 70 ... Oil pump, 71 ... Second oil passage portion, 72 ... Oil filter, 73 ... Third Oil passage 74, fourth oil passage 75, fifth oil passage 76, sixth oil passage 77, 77 7 oil passage, 80 ... oil cooler, 81 ... (oil cooler) inflow side oil hose, 82 ... (oil cooler) outflow side oil hose, 83 ... eighth oil passage, 84 ... ninth oil passage (exhaust port) (Cooling part), 85 ... 10th oil passage part (combustion chamber cooling part), 86 ... 11th oil passage part (intake port cooling part), 87 ... 12th oil passage part (spark plug insertion part cooling part), 88 ... 13th oil passage part, 90a ... 1st part, 90b ... 2nd part, 91 ... Spark plug insertion part, 95 ... Upper core, 96 ... Upper flow path part, 97 ... Lower core, 98 DESCRIPTION OF SYMBOLS ... Lower flow path part, 100 ... Lid member, 101 ... Projection part, 102 ... Mounting bolt, 103 ... Cam housing, 105 ... Annular groove, 105a-105c ... Arc-shaped part, 108 ... Oil temperature sensor, 110 ... Spark plug 112 ... Intake side squish area, 113 ... plug insertion side squish area.

Claims (5)

A crankcase, a cylinder, and a cylinder head in which a valve operating mechanism is accommodated,
The oil passage in the cylinder head burns the oil flowing from the exhaust port cooling section, which guides oil around the exhaust port provided in the cylinder head and sends it back to the oil passage in the cylinder. An oil passage structure for an engine having a combustion chamber cooling part that recirculates around the chamber,
An oil passage structure for an engine, wherein an intake port cooling section is provided between the combustion chamber cooling section and the intake port. The oil passage structure for an engine according to claim 1, wherein a spark plug insertion portion cooling section is provided between the combustion chamber cooling section and the spark plug insertion section. The intake port cooling section and the spark plug insertion section cooling section are an oil feed section that is sent from the combustion chamber cooling section provided in a cylinder to the cylinder head, and an oil return that is returned from the cylinder head to the combustion chamber cooling section. The engine oil passage structure according to claim 1, wherein the engine oil passage structure is constituted by a portion. The engine oil passage structure according to claim 3, wherein the combustion chamber cooling unit is partitioned between portions where the oil feed unit and the oil return unit are connected. The oil passage structure of the engine according to claim 1, wherein an oil temperature sensor is provided in an oil passage of the combustion chamber cooling portion or the intake port cooling portion.

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