COMBUSTION ENGINE

Abstract

Internal combustion engine, with: a crankcase (20); Flushing pumps (51L, 51R) for sucking engine oil flowing downwards from the crankcase (20); Oil separators (86L, 86R) mounted on pump housings (52L, 52R) of the scavenging pumps (51L, 51R) and designed to allow the engine oil entrained around a crankshaft (11) to drip off in the direction of oil intake openings (72aL, 72aR) of the scavenging pumps (51L, 51R); and guide elements (80L, 80R) attached to the oil intake openings (72aL, 72aR), wherein the guide elements (80L, 80R) have projections (84) projecting upwards from the oil suction openings (72aL, 72aR), the oil separators (86L, 86R) are arranged at upper end portions of the projections (84), and the guide elements (80L, 80R) are sandwiched between the oil separators (86L, 86R) and the pump housings (52L, 52R), characterized in that the oil separators (86L, 86R) are made of a metal, and the guide elements (80L, 80R) are made of a resin with a specific gravity lower than that of the oil separators (86L, 86R).

Description

The present invention relates to an internal combustion engine.In an internal combustion engine in the related art, for example, in JP 2008-32 009 A, it is disclosed that an air-oil separator for separating air from engine oil collected in a crankcase is provided, and a cover member configured to prevent the circulation of the engine oil to a crankcase from an oil pan made of a plate member is attached to an oil extraction device integrated with the separator.DE 10 2013 113 611 A1 shows an internal combustion engine according to the preamble of independent claim 1.DE 102 16 868 A1 shows a plastic oil deflector for fastening in a crankcase with oil returns.JP 2005-248 836 A shows an internal combustion engine with only one oil exhaust pump, wherein the oil separator is part of the crankcase.Incidentally, in the related art, it is conceivable to impart a degree of freedom in shape to oil control parts such as the cover member and change various settings by replacing these parts. In this case, depending on the attachment position of the oil control parts, it is necessary to partition the crankcase, which is troublesome. Specifically, in a dry sump engine forming a closed crankcase sump while a suction port of a scavenging pump is open in the closed crankcase sump, an opening area of the suction port is limited by the oil control parts.An aspect of the present invention is directed to providing an internal combustion engine that forms a crank chamber in which an oil suction port of a scavenge pump can be enlarged and an oil separator can be easily replaced.In order to achieve the above-mentioned purposes, an internal combustion engine according to an aspect of the present invention adopts the following configuration.One aspect of the present invention relates to an internal combustion engine comprising:a crankcase (20); scavenge pumps (51L, 51R) for sucking engine oil flowing downward from the crankcase (20); and oil separators (86L, 86R) attached to pump housings (52L, 52R) of the scavenge pumps (51L, 51R) and configured to drip the engine oil carried around a crankshaft (11) toward oil suction ports (72aL, 72aR) of the scavenge pumps (51L, 51R).According to the aspect of the aforementioned item (1), when the oil separators are attached to the scavenging pumps attached to a lower portion of a crank chamber forming portion, the following effects are exhibited. That is, compared to the case where the oil separators are attached to an inner wall of the crankcase, it is not necessary to provide a configuration in which the oil separators are attached to the inner wall of the crankcase. For this reason, the oil suction port of the scavenge pump can be enlarged and placed as close to the inner wall of the crankcase as possible. Accordingly, the amount of oil discharge by the scavenge pumps can be increased, and the oil resistance occurring in the crankcase can be reduced. In addition, it is possible to access the oil separators only due to the attachment and detachment of the scavenge pump without the need to divide the crankcase. Thus, the replacement operation of the oil separators is simplified, and adjustment of the change in shape or the like of the oil separators can be easily performed.The internal combustion engine further includes vanes (80L, 80R) attached to the oil suction ports (72aL, 72aR), the vanes (80L, 80R) having protrusions (84) projecting upward from the oil suction ports (72aL, 72aR), the oil separators (86L, 86R) being disposed at upper end portions of the protrusions (84), and the vanes (80L, 80R) being sandwiched between the oil separators (86L, 86R) and the pump housings (52L, 52R).According to the aforementioned aspect, when the oil separators are arranged to support the upper end portions of the protrusions of the vanes, the setting of the oil separators can be easily adjusted by changing the shape or the like of the vanes separated from the pump housings.Further, the oil separators (86L, 86R) are made of a metal, and the guide members (80L, 80R) are made of a resin having a specific gravity lower than that of the oil separators (86L, 86R).According to the aforementioned aspect, the oil separators are made of a metal to increase strength, and the oil separators may be made compact to be able to more easily approach the crankshaft. In addition, when the vanes upwardly protruding from the oil suction ports are made of a resin, the weight of the vanes can be reduced with a large volume, whereby weight reduction of the engine can be achieved.(2) In the aspect of the aforementioned numeral (1), the oil separators (86L, 86R) may include: fixing parts (87a) fixed to the pump housings (52L, 52R) of the scavenge pumps (51L, 51R); and a superimposing part (87b) superimposing the oil suction ports (72aL, 72aR) as viewed in a plan view.According to the aspect of the aforementioned item (2), when the oil separators are provided so as to overlap the oil suction ports of the scavenging pumps, the engine oil dropped downward onto the oil separator can be directly received by the oil suction port. For this reason, the oil discharge amount by the scavenging pumps can be further increased. In addition, when the size or the like of the overlap part of the oil separators is changed, an increased actual opening area (and suction capacity) of the oil suction port can be adjusted, and controllability of the pump capacity can be increased.(3) In the aspect of the aforementioned numerals (1) or (2), the oil separators (86L, 86R) may be disposed in a position in which edge portions (87b) are located near the crankshaft (11) as viewed in an axial direction of the crankshaft (11), and the edge portions (87b) may include a plurality of bent portions (89a, 89b, 89c) bent toward the crankshaft (11) as viewed in the axial direction.According to the aspect of the aforementioned item (3), the engine oil carried around the crankshaft can be effectively stripped off by the plurality of folded portions folded in the portions with an edge of the oil separators toward the crankshaft. Moreover, when the engine oil passes through the spaces between the plurality of bent portions, the air contained in the engine oil may be separated to achieve the effect of gas-liquid separation.(4) In the aspect of the aforementioned numeral (3), the plurality of bent portions (89a, 89b, 89c) may have different positions and angles as viewed in the axis direction.According to the aspect of the aforementioned item (4), the engine oil can be effectively stripped off, and the air contained in the engine oil can be separated according to an amount of the engine oil carried around the crankshaft.(5) In the aspect of any one of the above numerals (1) to (4), the internal combustion engine may include guide members (80L, 80R) attached to the oil suction ports (72aL, 72aR) and configured to narrow down an oil flow passage.According to the aspect of the aforementioned item (5), it is possible to collect and flow the engine oil toward the oil chambers of the scavenging pumps while receiving the engine oil with the enlarged oil suction ports. For this reason, the oil discharge amount by the scavenging pumps can be further increased.(6) In the aspect of any one of the above numerals (1) to (5), the oil suction ports (72aL, 72aR) of the scavenge pumps (51L, 51R) may be attached to an inner wall (22) of the crankcase (20) on a first plane (23c), and a rear attachment portion (68R) located behind the oil suction ports (72aL, 72aR) of the scavenge pumps (51L, 51R) may be attached to a rear inner wall (27) of the crankcase (20) on a second plane (68d) shifted below the first plane (23c).According to the aspect of the aforementioned item (6), since the rear portions of the scavenge pumps are attached to the crankcase in the region offset stepwise with respect to the oil suction ports of the scavenge pumps, the rear portions of the scavenge pumps can be attached to the crankcase in the region below and, immediately behind the transmission, behind the crankshaft while the oil suction ports are disposed near the crankshaft. Therefore, since the opening area of the oil suction ports of the scavenging pumps can be increased, the oil discharge amount by the scavenging pumps can be increased, and oil resistance occurring in the crankcase can be reduced.According to the aspect of the present invention, in the internal combustion engine forming the crank chamber, it is possible to increase the oil suction port of the scavenge pump and easily replace the oil separator. FIG. 1 is a left side view of a motorcycle according to an embodiment of the present invention. FIG. 2 is a right side view of an engine of the motorcycle, schematically illustrating an internal configuration. FIG. 3 is a front view of the motor. FIG. 4 is an enlarged view of a main part of FIG. 2. FIG. 5 shows a right side view of a pump unit of the motor. FIG. 6 is a front view of the pump unit. FIG. 7 is an exploded perspective view of the pump unit. FIG. 8 shows a top view of the pump unit. FIG. 9 is a cross-sectional view taken along line IX-IX of FIG. 8. FIG. 10 is a cross-sectional view taken along line X-X of FIG. 8. FIG. 11 is a bottom view of a crankcase in a state where the pump unit and the oil pan are removed. FIG. 12 is a cross-sectional view taken along line XII-XII of FIG. 11.Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. Further, the directions forward, rearward, leftward, rightward, etc. in the following description correspond to the directions in a vehicle described below, unless clearly stated otherwise in the context. In addition, at corresponding locations in the drawings used in the following description, an arrow FR indicates a forward direction with respect to a vehicle, an arrow LH indicates a leftward direction with respect to the vehicle, and an arrow UP indicates an upward direction with respect to the vehicle. In the descriptions and drawings of the embodiment, the pair of left and right members may be generally designated by removing "L" and "R" from their reference numerals.<>As illustrated in FIG. 1, a motorcycle (saddle riding vehicle) 1 of the embodiment includes a front wheel 2 and a rear wheel 3, front forks 4 for supporting the front wheel 2, swing arms 5 for supporting the rear wheel 3, a body frame 6 for supporting the front forks 4 and the swing arms 5, and an engine 7 (an internal combustion engine, an engine) supported by the body frame 6.Referring also to FIG. 2, the engine 7 is a four-cylinder V-type engine in which a rotational center axis C 1 of a crankshaft 11 is located in a vehicle width direction (a left / right direction). The engine 7 includes a crankcase 20, a forwardly tilted cylinder 31, and a rearwardly tilted cylinder 32.The crankcase 20 rotatably supports the crankshaft 11. An arrow F indicates a rotational direction of the crankshaft 11 in the drawings. The crankcase 20 receives the crankshaft 11 in its front portion and receives a transmission 16 in its rear portion.The crankcase 20 includes a crank chamber forming portion 21 for receiving a crank pin 12 and a crank arm 13 (crank arm) of the crankshaft 11, and a transmission case member 26 for receiving the transmission 16.An oil pan 40 is attached to a lower portion of the crankcase 20 from below. A pump unit 50, which will be described later, is attached to a lower portion of the crank chamber forming portion 21 from below.The forward tilted cylinder 31 and the rearward tilted cylinder 32 are provided above the front portion of the crankcase 20. The cylinder 31 tilted forward is diagonally upward and forward, and the cylinder 32 tilted rearward is diagonally upward and rearward. A piston 14 is inserted into each of the cylinder 31 tilted forward and the cylinder 32 tilted backward.Each of the pistons 14 is connected to the crankpin 12 of the crankshaft 11 via a connecting rod 15 (connecting rod). A reciprocating motion of the piston 14 is converted into a rotational motion of the crankshaft 11 via the connecting rod 15. A rotational driving force of the crankshaft 11 is transmitted to the transmission 16 via a clutch (not shown) and transmitted to the rear wheel 3 via, for example, a chain-type power transmission mechanism after a corresponding gear change is made.<Geschlossener Crankcase Sump>As shown in FIG. 2, the crank chamber forming portion 21 forms a pair of closed crankcases 23 which are independent of each other. The pair of closed crankcases 23 are arranged in a vehicle width direction. Each of the closed crankcase sumps 23 communicates with one of the left and right cylinders in the forward tilted cylinders 31 and the rearward tilted cylinders 32. Pumping loss caused by movement of the pistons is reduced by forming the crankcase closed bodies 23 and forcibly setting an internal pressure of the crankcase 20 to a negative pressure by means of scavenging pumps 51L and 51R, as described later. In addition, by discharging excess engine oil in the crank chamber, oil movement by the crankshaft 11 is reduced to suppress friction loss. Each of the pair of crankpins 12 provided in the crankshaft 11, each of the pair of crank webs 13 for supporting the crankpins 12, and each of the pair of connecting rods 15 connected to the crankpins 12 are respectively disposed in the closed crankcase bodies 23.Referring also to FIG. 3, in the four-cylinder V engine, the pair of left and right cylinder-corresponding connecting rods 15 in the forward tilted cylinders 31 and the rearward tilted cylinders 32 are connected to the left and right crankpins 12.The curved wall 22, which forms a downward protruding curved shape as viewed in a side view of FIG. 2 (as viewed in an axial direction of the crankshaft 11 as viewed in a crank axis direction), is provided in the lower portion of the crank chamber forming portion 21.Referring to FIGS. 4, 7 and 11, in the lower portion of the curved wall 22, a pair of openings 23 athat open the closed crankcase fuselages 23 downward are formed.Peripheral edge portions 72 bL and 72 bR of suction ports 72 aL and 72 aR of the pair of scavenging pumps 51L and 51R in the pump unit 50 respectively abut and are connected to peripheral edge portions 20 bof the curved wall 22 surrounding the openings 23 afrom below.Referring to FIG. 4, the transmission housing portion 26 defines a transmission chamber 28 that receives the transmission 16. A rear curved wall 27 having a downwardly protruding curved shape as viewed in a side view (in the crank axis direction) is provided at the lower portion of the gear housing part 26. A rear opening 28a which opens the transmission chamber 28 downward (into the oil pan 40) is formed in the rear curved wall 27. Engine oil (hereinafter referred to simply as oil) supplied to the transmission chamber 28 flows downward and flows back into the oil pan 40 from the rear opening 28 a.Referring to FIGS. 2 and 3, the oil pan 40 is attached to the crankcase 20 from below. The oil pan 40 is provided to project downward from a substantially horizontal lower end surface 20 cin the crankcase 20. The oil pan 40 is container-shaped and opens upward. A peripheral edge portion 40 bof an upper end opening 40 aof the oil pan 40 abuts and is connected to the peripheral edge portion 20 bof a lower end opening 20 aformed on the lower end surface 20 cof the crankcase 20 from below.The lower end surface 20 cof the crankcase 20 is a plane, and the lower end opening 20 aand the peripheral edge portion 20 band the upper end opening 40 aand the peripheral edge portion 40 bare provided along the lower end surface 20 c. The peripheral edge portion 20 bof the lower end opening 20 aand the peripheral edge portion 40 bof the upper end opening 40 ahave the same shape and are coupled to each other in a state of adhering to each other via an oil seal along the lower end surface 20 c. The peripheral edge portion 20 bof the lower end opening 20 aand the peripheral edge portion 40 bof the upper end opening 40 aadline with each other in an oil-tight manner and are coupled to each other over the entire circumference.Referring to FIGS. 2 and 4, an oil storage space 41 in which oil is stored is formed in the oil pan 40. The oil storage space 41 communicates with a lower space 24 of the crankcase 20 (a space below the curved walls 22 and 27 respectively). The pump unit 50 is disposed in the lower space 24 of the crankcase 20.<>As illustrated in FIGS. 4 to 10, the pump unit 50 is attached to a lower surface of the curved wall 22 of the lower portion of the crank chamber forming part 21. The pump unit 50 includes oil pumps that are composed of internal gear pumps having a plurality of trochoid tooth profiles arranged in the vehicle width direction (crank axis direction). The pump unit 50 includes the left scavenging pump 51L, a feed pump 51C, and the right scavenging pump 51R in the order from the left to the right.Referring to FIG. 8, the left scavenging pump 51L, the feed pump 51C, and the right scavenging pump 51R have rotors 53L, 53C, and 53R in housings (pump housings) 52L, 52C, and 52R, respectively.Referring to FIG. 10, the rotors 53L, 53C and 53R have annular outer rotors 54 rotatably and parallel fixedly provided in the cylindrical spaces in the housings 52L, 52C and 52R, and inner rotors 55 respectively disposed in the outer rotors 54 and rotatably provided about axes eccentric to the outer rotor 54. The outer rotor 54 has internal teeth, and the inner rotor 55 has more external teeth than internal teeth. The outer rotor 54 and the inner rotor 55 form an oil chamber 56 between the internal teeth and the external teeth.When a drive shaft 66 rotates in association with the rotation of the crankshaft 11, the outer rotor 54 and the inner rotor 55 are rotated while changing the capacity of the oil chamber 56, and a liquid in the oil chamber 56 is pumped to a downstream side.The pump unit 50 includes a single pump body 60 and a single drive shaft 66 shared by the left scavenging pump 51L, the feed pump 51C, and the right scavenging pump 51R.Referring to FIGS. 7 to 9, the pump body 60 includes the left and right divided bodies 61 and 63 disposed on left and right outer sides, and a first intermediate divided body 62 and a second intermediate divided body 64 disposed between the left and right divided bodies 61 and 63. The plurality of divided bodies 61 to 64 are arranged in the order of the left divided body 61, the first intermediate divided body 62, the second intermediate divided body 64, and the right divided body 63 from the left side. The plurality of divided bodies 61 to 64 are fastened to each other in the vehicle width direction by a plurality of bolts B 1 and integrated with each other. When the pump body 60 is divided into the plurality of divided bodies 61 to 64 in the vehicle width direction, pump rotors 57 (the outer rotor 54 and the inner rotor 55) of the respective pumps 51L, 51C, 51R can be mounted. The term "intermediate" used in the embodiment denotes not only a center of an object between both ends but also a region of the object between both ends.The drive shaft 66 is provided rotatably about an axis (a pump rotation center axis) C 2 in the vehicle width direction. The drive shaft 66 has left and right end portions that project outward from left and right sides of the pump body 60. For example, a drive gear 36 to which the rotation of the crankshaft 11 is transmitted may be integrally and rotatably mounted on a right end portion of the drive shaft 66. For example, an output gear 37 for transmitting rotation to another accessory such as a water pump (not shown) or the like is integrally and rotatably attached to a left end portion of the input shaft 66. The drive shaft 66 coaxially supports the inner rotors 55 of the left scavenging pump 51L, the feed pump 51C, and the right scavenging pump 51R.< Pump>As illustrated in FIGS. 4 to 10, the housings 52L and 52R of the left scavenging pump 51L and the right scavenging pump 51R have rotor accommodating parts 70L and 70R for accommodating the pump rotors 57 (the outer rotor 54 and the inner rotor 55), and suction ports 71L and 71R and discharge ports (not illustrated) continuous with the rotor accommodating parts 70L and 70R, and independent of each other, respectively.Each of the rotor accommodating parts 70L and 70R forms a columnar accommodating space that follows the outer shape of the respective pump rotors 57. The rotor accommodating parts 70L and 70R are provided to project downward from the suction ports 71L and 71R extending downward from the oil suction ports 72 aL and 72 aR, respectively. Reference numeral 23 cin the drawings indicates a plane in the lower portion of the curved wall 22 on which the pair of openings 23 aare formed (hereinafter referred to as a pump mounting surface).Each of the suction ports 71L and 71R is formed to extend forward and upward to the end of a corresponding front upper portion of the rotor accommodating parts 70L and 70R. The oil suction ports 72 aL and 72 aR are open in the upper end surfaces of the suction ports 71L and 71R, respectively. The suction ports 72 aL and 72 aR are connected to the pair of ports 23 a(see FIG. 11 ) formed in the curved wall 22 of the crankcase 20, respectively. The suction ports 71L and 71R form oil flow passages that extend from the oil suction ports 72 aL and 72 aR to the oil chambers 56 of the pump rotors 57, respectively. The oil flow passages of the suction ports 71L and 71R are communicated with the corresponding closed crankcase bodies 23 through the oil suction ports 72 aL and 72 aR and the ports 23 a, respectively.Discharge ports of the left scavenging pump 51L and the right scavenging pump 51R have oil discharge ports at outer sides of the corresponding one of the rotor accommodating parts 70L and 70R in the vehicle width direction (not illustrated).Referring to FIGS. 4, 7, and 11, the openings 23 aand their peripheral edge portions 23 band suction ports 72 aand their peripheral edge portions 72 bare provided along planes (pump attachment surfaces 23 c) inclined forward and downward, respectively. The peripheral edge portions 72 bof the suction ports 72 aof the left scavenging pump 51L and the right scavenging pump 51R abut and are coupled to the peripheral edge portions 23 bof the openings 23 aof the crankcase 20 from below.The peripheral edge portions 72 bof the suction ports 72 aand the peripheral edge portions 23 bof the ports 23 aare respectively coupled in a state of being formed in the same shape with each other and being in close contact with each other via the oil seal along the pump attachment surfaces 23 c. The peripheral edge portions 72 bof the suction ports 72 aand the peripheral edge portions 23 bof the ports 23 aadline with each other in an oil-tight manner and are coupled to each other over the entire circumference.The suction ports 72 aL and 72 aR are formed in a substantially rectangular shape when viewed in a plan view, and their front and rear sides are arranged in the vehicle width direction. The front portions of the suction ports 72 aL and 72 aR become front plate portions wider than the rear portions in the vehicle width direction.Referring to FIGS. 7 to 9, guide members 80L and 80R are respectively disposed in the suction ports 72 aL and 72 aR. The guide members 80L and 80R have guide portions 81 extending from heights overlapping the pump mounting surfaces 23 cto below the pump mounting surfaces 23 c(in suction ports 71), and protrusions 84 projecting upward from front sides of the guide portions 81, respectively. The protrusions 84 support oil separators 86L and 86R configured to scrape off the engine oil carried around the crankshaft 11. The vanes 80L and 80R and the oil separators 86L and 86R will be described in detail below.<Feed Pump>As shown in FIGS. 5 to 8, the housing 52C of the feed pump 51C includes a rotor accommodating part (no reference numeral) for accommodating the pump rotors 57 (the outer rotor 54 and the inner rotor 55), an intake pipe 75 extending downward from the rotor accommodating part and connected to a strainer 77, and a discharge pipe 76 curved forward after being parallel to the intake pipe 75 downward and connected to oil passages that reach the parts of the engine 7. The rotor accommodating part of the feed pump 51C is sandwiched between the rotor accommodating parts 70L and 70R of the left and right scavenging pumps 51L and 51R in the left / right direction, and is provided so as to overlap the rotor accommodating parts 70L and 70R as viewed in a side view.The strainer 77 extends downward from the intake pipe 75 and is leaked in the engine oil stored in the oil pan 40. The feed pump 51C draws the engine oil in the oil pan 40 via the strainer 77, and pumps the engine oil from the discharge pipe 76 to the oil passages. Reference numeral 78 in FIG. 6 shows a relief valve connected to a side portion of the discharge port.<Membranous Valve>As illustrated in FIGS. 5, 6, and 10, the pump unit 50 includes a pair of left and right reed valves 90L and 90R. The left and right reed valves 90L and 90R are provided so as to correspond to the left and right closed crankcases 23, respectively. The left reed valve 90L is provided in the suction port 71L of the left scavenging pump 51L, and the right reed valve 90R is provided in the suction port 71R of the right scavenging pump 51R. The left and right reed valves 90L and 90R allow a flow of the engine oil in one direction from the suction ports 71L and 71R to the oil storage space 41 outside the pump unit 50, and restrict a flow in an opposite direction.Referring to FIG. 10, the left and right reed valves 90L and 90R are provided in a connection part 92 that is to bring the inside and the outside of the suction ports 71L and 71R into communication with each other, respectively. The left and right reed valves 90L and 90R have valve bodies 93 for opening and closing the connection part 92 according to an internal pressure of the respective closed crankcase bodies 23, and plugs 94 for limiting the movement of the valve bodies 93 upon valve opening.The connection part 92 passes through front lower walls 71 aof the suction ports 71L and 71R in a normal direction (a rearward direction inclined forward and downward). The connecting part 92 brings the inside of the suction ports 71L and 71R (the inside of the closed crankcase 23's) and the oil storage space 41 in the oil pan 40 into communication with each other. The connecting part 92 has a first opening 92 athat opens outside the suction ports 71 (in the oil storage space 41) and a second opening 92 bthat opens inside the suction ports 71 (in the closed crankcase bodies 23).The valve body 93 is a flat plate-shaped elastic member that is elastically deformable and is disposed to close the first opening 92 aof the connection member 92. The valve body 93 is disposed along a flat peripheral edge portion of the first opening 92 a. The valve body 93 closes the entire first opening 92 afrom an outer side of the front bottom wall 71 a(on the oil storage space 41 side). The valve body 93 forms a rectangular plate shape, and its upper and lower sides are arranged in the vehicle width direction.The valve bodies 93 have upper side portions (portions having a side edge) fixed and fixed to the front lower walls 71 aby a pair of bolts B 5. Lower side portions (portions having the other side edge) of the valve bodies 93 are free ends separable from the pump body 60. The valve bodies 93 can be elastically deformed such that lower surfaces are separated from the front lower walls 71 according to an increase in the internal pressure of the closed crankcase hulls 23. Accordingly, the connecting part 92 can be opened to communicate the closed crankcase sumps 23 and the oil storage space 41 with each other.A direction in which each of the reed valves 90L and 90R is open (a valve opening direction) is a diagonal direction rearward downward along the front bottom wall 71 a. The rotor accommodating parts 70L and 70R protruding downward in the housings 52L and 52R of the left and right scavenging pumps 51L and 51R (on the oil storage space 42 side) are arranged in the direction in which the reed valves 90L and 90R are open. When the reed valves 90L and 90R are open and the engine oil is discharged from the crank case closed bodies 23 side into the oil storage space 41, the engine oil impinges on the rotor receiving parts 70L and 70R. Accordingly, separation (gas-liquid separation) of the air contained in the engine oil is achieved.The outer shape of the plugs 94 substantially corresponds to the shape and the size of the valve bodies 93 as viewed in the normal direction of the valve bodies 93, and the plugs 94 are disposed so as to overlap the valve bodies 93 from the oil storage space 41 side. The plugs 94 and the valve bodies 93 are arranged such that their outer shapes substantially coincide. The plugs 94 are spaced from the valve bodies 93. The upper side portions of the plugs 94 are fastened and fixed to the front lower walls 71 aby the pair of bolts B 5 together with the upper side portions of the valve bodies 93. The plugs 94 are formed in a frame shape with openings 94a on the inner peripheral side for weight reduction, for example.Referring to FIG. 10, in the up / down direction perpendicular to the pump attachment surfaces 23 cin a side view, the second openings 92 bof the connection part 92 of the suction ports 71L and 71R are located on the side of the closed crankcase 23 above upper ends 57 aof the pump rotors 57 of the scavenging pumps 51L and 51R (high position). When the second opening 92 bof the connection part 92 is located below the pump rotors 57 of the scavenging pumps 51L and 51R (low position), it may impair the oil suction performance of the scavenging pumps 51L and 51R.That is, when a flow of the engine oil into the suction ports 71L and 71R of the scavenging pumps 51L and 51R and the opening of the reed valves 90L and 90R due to an increase in the internal pressure of the closed crankcase 23 occur simultaneously, the following events are conceivable. That is, when the engine oil sucked into the pump rotors 57 of the scavenging pumps 51L and 51R flows into the suction ports 71L and 71R, it is conceivable that the flows of the engine oil discharged from the connection part 92 to the outside of the suction ports 71 via the reed valves 90L and 90R are mutually attractive.In the embodiment, when the second opening 92 bof the connecting part 92 on the side of the closed crankcase sump 23 is disposed above the upper end 57 aof the pump rotor 57 of each of the scavenging pumps 51L and 51R (high position), the effect on the oil suction performance of each of the scavenging pumps 51L and 51R is suppressed. That is, the flow of the engine oil sucked into the pump rotors 57 of the scavenging pumps 51L and 51R and the flow of the engine oil discharged from the connection part 92 to the outside of the suction ports 71 via the reed valves 90L and 90R are prevented from attracting each other. In addition, when the second opening 92 bside is above the first opening 92 aof the connection member 92, an oil storage portion 92 cthat extends downward from the second opening 92 bside is formed. This configuration also suppresses the effect on the oil suction performance of the respective scavenging pumps 51L and 51R.< Structure>As illustrated in FIGS. 4, 7, and 10, a plurality of fixing portions 68F and 68R for fixing the pump unit 50 to the inner wall (the respective curved walls 22 and 27) of the crankcase 20 are provided on the pump body 60. The fixing portions 68F and 68R include the front fixing portion 68F at a front portion of the pump body 60 and the rear fixing portion 68R at a rear portion of the pump body 60. The fixing portions 68F and 68R are each cylindrical and are arranged so as to be perpendicular to the pump attachment surfaces 23 c(sealing surfaces) in the axis direction. Upper and lower end surfaces of the attachment portions 68F and 68R are formed in parallel to the pump attachment surfaces 23 c. Bolts B 2 and B 3 for fastening to the crankcase 20 are inserted through the fastening portions 68F and 68R, and the bolts B 2 and B 3 are screwed and fastened into female screw portions provided in the curved walls 22 and 27. Reference numeral 68 cin the side view denotes an attachment surface of the front attachment portion 68F, and reference numeral 68 ddenotes an attachment surface of the rear attachment portion 68R. Mounting surfaces 68 cand 68 dare planes along upper end surfaces of the mounting portions 68F and 68R, respectively, and extend parallel to each other. The attachment surface 68 cof the front attachment portion 68F coincides with the pump attachment surface 23 c.The front attachment portion 68F is provided in the vicinity of left and right corners of a front side (side having an edge) of the respective suction ports 72 aL and 72 aR in the left and right scavenging pumps 51L and 51R. The bolt B 2 is inserted through the front fastening portion 68F in an up / down direction perpendicular to the pump attachment surfaces 23 c(hereinafter referred to as an up / down direction of the pump). When the bolt B 2 is screwed and fastened in the internal thread portion of the curved wall 22, the front portion of the pump body 60 is fastened and fixed to the crankcase 20.A component fixing portion 69 for integrally fixing an oil separator 86, a guide member 80, and the pump body 60 is provided more inward in the suction ports 72 ain the left / right direction than the front fixing portion 68F located at the front of the suction port 72 a. The component mounting portion 69 is formed in a cylindrical shape, the front mounting portion 68F and the axial direction are parallel to each other, and the upper and lower end surfaces thereof are formed in parallel to the pump mounting surfaces 23 c. A bolt B 4 is inserted through the component fixing portion 69 from below in the pump up / down direction. When the bolt B 4 is screwed and fastened in a boss 88 of the oil separator 86, the oil separator 86, the baffle 80, and the pump body 60 are integrally fastened and fixed to each other. The upper surface (hub attachment surface) of the component mounting portion 69 coincides with the pump attachment surface 23 c.The rear attachment portion 68R is provided at a position displaced rearward and downward from the suction ports 72 aL and 72 aR in the left and right scavenging pumps 51L and 51R, respectively. The rear attachment portion 68R is disposed at a position shifted in parallel rearward and downward from the front attachment portion 68F. The bolt B 3 is inserted through the rear fastening portion 68R from below in the pump up / down direction. When the bolt B 3 is screwed and fastened in the internal thread portion of the rear curved wall 27, the rear portion of the pump body 60 is fastened and fixed to the crankcase 20.Referring to FIGS. 4, 7, and 10, the engine 7 of the embodiment includes the oil separator 86 for scraping the engine oil carried around the crankshaft 11 (specifically, the crank arm 13 having a large rotational radius). The oil separator 86 is supported by the pump unit 50 via the guide element 80. When the oil separator 86 is supported by the crankcase 20, a support shape for supporting and fixing the oil separator 86 is provided in the vicinity of the openings 23 aof the curved wall 22 in the crankcase 20.In this case, it is conceivable that the pump unit 50 is disposed near a rear side in order to avoid the support shape. Then, in order to avoid the transmission 16 of the rear portion of the crankcase 20, a measure such as a large inclination of the pump attachment surfaces 23 cor the like may take place. Then, the effective area of the suction ports 72a provided for receiving the engine oil flowing downward from the closed crankcase 23 as viewed in plan view can be substantially narrowed. In addition, when the rear fixing portion 68R is provided in a position avoiding the transmission 16 toward the rear, the pump unit 50 may become large at the rear.By constructing the oil separator 86 in the embodiment to support the pump unit 50, the support shape constructed to support the oil separator 86 is not required in the crankcase 20, and the pump unit 50 can be placed closer to the front side. Accordingly, no measure such as a large inclination of the pump mounting surfaces 23 cis necessary to be taken, and it becomes easier to expand the effective area of the suction ports 72 awhen viewed in a plan view.The pump unit 50 supports the oil separator 86 (a separator main body 87, described later) on the upper end surface of the guide member 80 that protrudes upward from the suction port 72 a. The guide member 80 prevents an increase in the weight of the pump unit 50 because it is made of a resin or the like having a specific weight lower than that of the oil separator 86 and the pump body 60. The oil separator 86 can adjust an actual opening area (and a scavenging capacity) of each of the suction ports 72 aby extending so as to overlap the suction ports 72 awhen viewed in a plan view.A degree of freedom in the shape of the oil separator 86 is high, and moreover, replacement of the oil separator 86 is facilitated by attaching the oil separator 86 to the pump unit 50. The pump unit 50 avoids the presence of the bolt head portion on the side of the closed crankcases 23 by passing the bolts B 2 and B 3 through the crankcase 20 and fastening it thereto from below. The rear attachment portion 68R prevents an increase in the size of the pump unit 50 on the rear side by moving downward in parallel from the pump attachment surface 23 cto bypass the transmission 16.<>As shown in FIGS. 7 to 9, the guide members 80L and 80R have the guide portions 81 disposed in the suction ports 72 aand the protrusions 84 protruding upward from the suction ports 72 a, respectively.The guide portions 81 include front guide portions 82 disposed on inner sides of the front plate portions of the suction ports 72 aand left and right guide portions 83L and 83R disposed on inner sides of left and right side portions of the suction ports 72 a. The guide portions 81 integrally include the front guide portions 82 and the left and right guide portions 83L and 83R, and are C-shaped as viewed in a plan view.The front guide portions 82 define substantial front end positions of the suction ports 72a. The front guide portions 82 form the front inclined surfaces 82 athat are inclined rearward as they extend downward (inner sides of the suction ports 72 a). Portions of the front guide portions 82 in front of the front inclined surfaces 82 aform hanging portions that are substantially located on the outside of the suction ports 72 a. The protrusions 84 are formed above the front guide portions 82.Referring to FIG. 10, lower end portions of the front guide portions 82 are located near the flow passage forming parts 71 b,which overhang in the suction ports 71 in the front lower walls 71 aof the suction ports 71. Between the lower end portions of the front guide portions 82 and the flow passage forming members 71b, there are formed narrow passages 71c. Oil storage portions 71d within the opening are formed in front of the narrow passages 71c. The second openings 92 bof the connection part 92 are open in the oil storage regions 71 dinside the opening.Referring to FIGS. 7 to 9, the left and right guide portions 83L and 83R are formed asymmetrically with each other and correspond to differences between positions of the suction ports 72 aand the corresponding pump rotors 57 in the left / right direction.That is, the suction ports 72 aL and 72 aR of the scavenging pumps 51L and 51R are disposed at positions in the left / right direction deviating from the pump rotors 57. The suction ports 72 aL and 72 aR are arranged to be more inside than the corresponding pump rotors 57 in the left / right direction.The suction port 72 aL of the left scavenging pump 51L is disposed so as to deviate rightward from the corresponding pump unit 50. The suction port 72 aR of the right scavenging pump 51R is disposed so as to deviate leftward from the corresponding pump unit 50. Each of the suction ports 72 aL and 72 aR is disposed at a position corresponding to the crankpin 12 of the crankshaft 11. The pump rotors 57 of the left and right scavenging pumps 51L and 51R are disposed at positions appropriate for the pump unit 50. The suction ports 71L and 71R are formed to switch the oil flow passage in the left / right direction from the corresponding suction ports 72 aL and 72 aR to the pump rotors 57.The guide member 80L of the left scavenge pump 51L includes a large right guide portion 83R having a relatively large lateral width and a small left guide portion 83L having a relatively small lateral width. The right guide portion 83R forms a right inclined surface 83Ra inclined so as to be arranged as going downward leftward (inner sides of the suction ports 72 a). The left guide portion 83L forms a left inclined surface 83La inclined so as to be arranged as going downward to the right (inner sides of the suction ports 72 a).The guide member 80R of the right scavenge pump 51R includes the large left guide portion 83L having a relatively large lateral width and the small right guide portion 83R having a relatively small lateral width and a small length in the longitudinal direction. The left guide portion 83L forms the left inclined surface 83La inclined so as to be arranged as going downward to the right (inner sides of the suction ports 72 a). The right guide portion 83R forms the right inclined surface 83Ra inclined so as to be arranged as going downward leftward (inner sides of the suction ports 72 a).The guide portions 81 are formed such that the oil flow passage is also narrowed downward in one of the front / rear direction and the left / right direction.The protrusions 84 are provided so as to protrude upward from front sides of the guide portions 81 (the front guide portions 82). The protrusion 84 is formed in a substantially rectangular parallelepiped shape, and a flat top surface is located near the crankshaft 11. A pair of left and right cut-outs 84a corresponding to the pair of left and right bosses 88 of the oil separator 86 are formed at end faces of the protrusions 84. The left and right cut-outs 84a have cylindrical inner peripheral surfaces corresponding to outer peripheral surfaces of the cylindrical bosses 88 and opening the front portions of the inner peripheral surfaces forward.<>As illustrated in FIGS. 4 to 8, each of the oil separators 86L and 86R integrally includes the separator main body 87 having a substantially rectangular plate shape when viewed in a plan view and supported by the upper surface portion of the protrusion 84, and the pair of left and right bosses 88 fixed to the lower surface of the separator main body 87.The separator main body 87 includes a fixing part 87 athat overlies and is fixed to an upper side portion of the protrusion 84, and a rear edge portion 87 b(overlaying part) that is continuous with a rear side of the fixing part 87 awhen viewed in a plan view and overhangs at a position overlying the oil suction port 72 a. The upper surfaces of the bosses 88 are fixed to both left and right lower surfaces of the fixing part 87 a, respectively. The rear edge portion 87 bextends along the crankshaft 11 in the axial direction and is disposed such that its tip side is closer to the crankshaft 11.The oil separator 86 is disposed below the crankshaft 11 to align the rear edge portion 87 b, as viewed in the axial direction of the crankshaft 11, in a reverse rotational direction of the crankshaft 11. The engine oil adhering and carried on and around the outer periphery of the crankshaft 11 (the crank arm 13) is discharged to hit the rear edge portion 87 bof the oil separator 86 and is discharged downward. The stripped engine oil flows downward and is received in the oil suction ports 72a directly below the oil separator 86.When a large amount of engine oil adheres to the outer periphery of the crank arm 13, friction occurs in a region where a distance between the crank arm 13 and the inner wall of the crankcase is narrowed due to a flow resistance of the engine oil. On the other hand, the oil resistance occurring in the crankcase 20 is reduced by the engine oil being correspondingly stripped off at the outer periphery of the crank arm 13.The rear edge portion 87 bhas a bent portion bent upward toward the crankshaft 11 as viewed in the axial direction of the crankshaft 11. The bent portion has a plurality of uniformly bent portions 89a, 89b, and 89c disposed with a gap in the axial direction. Subsequently, a portion of the separator main body 87 except for the bent portion is a flat plate portion 87 c. A folded angle of each of the uniformly bent portions 89 a, 89 b, and 89 cwith respect to the flat plate portion 87 cis in a range of an acute angle when an angle is 0 degrees in the case of a flat plate shape without bending. Each of the unitary bent portions 89a, 89b and 89c is formed at an angle with its tip side directed in the reverse rotational direction of the crankshaft 11. Each of the unitary bent portions 89 a, 89 b, and 89 cis close to an outer peripheral portion of the crank arm 13, and scrapes off the engine oil carried around the crankshaft 11 and the connecting rod 15.When the engine oil carried around the crankshaft 11 and containing the air impinges on the bent portion of the oil separator 86, the air is separated from the engine oil to achieve a gas-liquid separation effect. That is, when the engine oil containing air passes through the gaps between the adjacent uniformly bent portions 89 a, 89 b, and 89 c, the air is removed from the engine oil, and the engine oil remaining in the oil separator 86 is guided to the oil suction ports 72 a.The bent portion of the oil separator 86 has the following bent portions as the plurality of uniformly bent portions 89 a, 89 b, and 89 c. That is, the bent portion of the oil separator 86 includes a first bent portion 89 aprovided with a relatively large width including a center portion of the separator main body 87 in the left / right direction, a pair of left and right second bent portions 89 blocated at the leftmost and rightmost sides of the separator main body 87 and provided with a relatively small width, and a pair of left and right third bent portions 89 cdisposed between the first bent portion 89 aand the left and right second bent portions 89 band provided with the same small width as the second bent portions 89 b.The bent portions 89 a, 89 b, and 89 care located at different folded positions along the flat plate portion 87 cin the forward / rearward direction (hereinafter referred to as a separator forward / rearward direction) as viewed in the axial direction of the crankshaft 11. In the separator front / rear direction, the folded positions of the second bent portions 89 bof the left and right outermost sides are located at the foremost side (base end side), the folded position of the first bent portion 89 ais located at the closest position, and the folded positions of the third bent portions 89 care located between the first and second bent portions 89 aand 89 bon the rearmost side (tip side).The bent portions 89 a, 89 b, and 89 chave different lengths from the folded positions to the tips as viewed in the axial direction of the crankshaft 11. Specifically, the first bent portion 89 ais the largest length (the tip is closest to the crank arm 13), the second bent portions 89 bare the second longest, and the third bent portions 89 care the shortest.The bent portions 89 a, 89 b, and 89 chave different folded angles with respect to the flat plate portion 87 cwhen viewed in the axial direction of the crankshaft 11. Specifically, the folded angle of the first bent portion 89 ais the largest, the folded angle of the second bent portions 89 bis the second largest, and the folded angle of the third bent portions 89 cis the smallest.In the case of the V 4- engine of the embodiment, the crankshaft 11 has the pair of crankpins 12, and each of the crankpins 12 is supported by the pair of crank webs 13 (hereinafter referred to as a pair of crank webs). The left oil separator 86L is provided to correspond to a left pair of crank webs, and the right oil separator 86R is provided to correspond to a right pair of crank webs. The left scavenge pump 51L collects the engine oil mainly returning from the left cylinder of the front and rear cylinders 31 and 32 into the crankcase 20, and the right scavenge pump 51R collects the engine oil mainly returning from the right cylinder of the front and rear cylinders 31 and 32 into the crankcase 20.Referring to FIGS. 5 and 6, the pair of bosses 88 are integrally provided on both left and right sides of the oil separator 86. Each of the bosses 88 is arranged in the axial direction oriented in the plate thickness direction of the separator main body 87. Each of the bosses 88 has an upper surface that abuts the lower surface of the separator main body 87 and is connected to the separator main body 87 by, for example, a means such as appropriate welding or the like. An internally threaded hole 88 ais formed in each of the bosses 88 along an axial center, and the internally threaded hole 88 ais open in the bottom.Referring to FIG. 7, each of the bosses 88 is inserted into and locked to the cutout 84 aformed at the front of the protrusion 84 of the guide member 80 from above. In this state, the bolt B 4 is inserted through the component fixing portion 69 of the pump body 60 from below, the bolt B 4 is screwed and fixed in the female screw hole 88 aof each of the bosses 88, and thus the oil separator 86, the baffle 80, and the pump body 60 are integrally fixed to each other. Here, a portion having the protrusion 84 of the guide member 80 is sandwiched between the oil separator 86 and the pump body 60. Accordingly, the baffle 80 is fixed to the pump body 60, and the oil separator 86, the baffle 80, and the pump body 60 are integrated with each other.The separator main body 87 and each of the bosses 88 are integrally formed of a metal such as aluminum alloy or the like. On the other hand, the guide member 80 having a relatively larger volume than that of the oil separator 86 is integrally formed of a resin material such as fiber-reinforced plastic or the like. The guide member 80 prevents an increase in weight by being formed of a synthetic resin having a lighter specific gravity than that of the metal of the oil separator 86. The guide member 80 is sandwiched and fixed between the oil separator 86 and the pump body 60, thereby eliminating the need for a fixing structure such as a separate fixing portion or the like and simplifying the configuration and preventing weight increase in this respect.As described above, the oil separator 86 can adjust an actual opening area (scavenging performance) of the exhaust ports 72 aby changing winding allowance at the exhaust ports 72 awhen viewed in a plan view. The oil separator 86 can adjust an oil scraping amount by changing a shape or the like of the bent portion. A change in winding allowance, the shape of the bent portion, or the like is made by the replacement of the oil separator 86.In the embodiment, when the oil separator 86 is supported on the pump unit 50, replacement of the oil separator 86 can be easily performed by attaching and detaching the pump unit 50. That is, even when the crankcase 20 is not disassembled, access to the bolts B 2 and B 3 for fixing the pump unit 50 to the crankcase 20 is possible by removing the oil pan 40 and opening the lower end opening 20 aof the crankcase 20, and replacement of the oil separator 86 is possible by removing the bolts B 2 and B 3 and removing the pump unit 50.FIG. 11 is a bottom view showing the lower end opening 20 aof the crankcase 20 from below.As illustrated in FIGS. 11 and 12, when the pump unit 50 is removed, the pair of openings 23 aof the curved wall 22 are exposed toward the lower end opening 20 a. The openings 23 aare provided so as to be enlarged in accordance with enlargement of the suction ports 72 aL and 72 aR of the left and right scavenging pumps 51L and 51R, respectively, when viewed in a plan view. For this reason, a tool T can access a fastening bolt B 6 of a large end portion of the connecting rod 15 of the closed crankcase sump 23 that holds the crankpin 12 through the lower end opening 20 aand each of the openings 23 a. Accordingly, replacement of the connecting rod metal may be performed without disassembling the crankcase 20.As described above, the engine 7 according to the embodiment includes the crank chamber forming part 21 for forming the closed crankcases 23, the scavenging pumps 51L and 51R that are attached to the lower portion of the crank chamber forming part 21 and configured to suck the engine oil flowing downward from the closed crankcases 23, and the oil separators 86L and 86R that are attached to the pump housings 52L and 52R of the scavenging pumps 51L and 51R and configured to drain the engine oil carried around the crankshaft 11 toward the oil suction ports 72 aL and 72 aR of the scavenging pumps 51L and 51R.According to the configuration, when the oil separators 86L and 86R are attached to the scavenging pumps 51L and 51R attached to the lower portion of the crank chamber forming part 21, the following effects are exhibited. That is, compared to the case where the oil separators 86L and 86R are attached to the inner wall of the crankcase 20, it is not necessary to provide the configuration for attaching the oil separators 86L and 86R to the inner wall of the crankcase 20. Thus, the oil suction ports 72 aL and 72 aR of the scavenging pumps 51L and 51R can be enlarged and can be disposed as close as possible to the inner wall of the crankcase 20. Accordingly, it is possible to effectively discharge the oil stored in the scavenging pumps 51L and 51R. For this reason, since more engine oil than necessary can be prevented from collecting in the crankcase 20, oil resistance occurring in the crankcase 20 can be reduced. In addition, it is possible to access the oil separators 86L and 86R by simply attaching and detaching the scavenge pumps 51L and 51R without partitioning the crankcase 20. Thus, the replacement work for the oil separators 86L and 86R is facilitated, and adjustment of the change in shape or the like of the oil separators 86L and 86R can be easily performed.In the engine 7, the oil separators 86L and 86R include the fixing parts 87 afixed to the pump housings 52L and 52R of the scavenging pumps 51L and 51R and overlapping parts (the rear edge portions 87 b) overlapping the oil suction ports 72 aL and 72 aR when viewed in a plan view.According to the configuration, when the oil separators 86L and 86R are provided so as to overlap the oil suction ports 72 aL and 72 aR of the scavenging pumps 51L and 51R, it is possible to directly receive the engine oil dropped from the oil separators 86L and 86R into the oil suction ports 72 a. Thus, the oil discharge amount by the scavenging pumps 51L and 51R can be further increased. Moreover, when the size or the like of the interference part between the oil separators 86L and 86R is changed, the increased actual opening area (scavenging capacity) of the oil suction ports 72 acan be adjusted, and the controllability of the pump capacity can be increased.In the engine 7, the oil separators 86L and 86R are disposed in a position in which the rear edge portion 87 bis located near the crankshaft 11 when viewed in the axial direction of the crankshaft 11, and the rear edge portion 87 bhas the plurality of bent portions 89 a, 89 b, and 89 c bent toward the crankshaft 11 when viewed in the axial direction.According to the configuration, the engine oil carried around the crankshaft 11 can be effectively stripped by the plurality of bent portions 89 a, 89 b, and 89 c bent toward the crankshaft 11 in the rear edge portions 87 bof the oil separators 86L and 86R. In addition, when the engine oil passes through the spaces between the bent portions 89 a, 89 b, and 89 c, the air contained in the engine oil can be separated to achieve the gas-liquid separation effect.In the motor 7, the plurality of bent portions 89 a, 89 b, and 89 chave different positions and angles as viewed in the axis direction.According to the configuration, the engine oil can be effectively stripped off, and the air contained in the engine oil can be separated according to an amount or the like of the engine oil carried around the crankshaft 11.In the engine 7, the guide members 80L and 80R attached to the oil suction ports 72 aL and 72 aR and configured to narrow the oil flow passages downward are provided.According to the configuration, the engine oil can collect and flow to the oil chambers of the scavenging pumps 51L and 51R while the engine oil is accommodated in the enlarged oil suction ports 72 a. Thus, the oil discharge amount by the scavenging pumps 51L and 51R can be further increased.In the engine 7, the guide members 80L and 80R attached to the oil suction ports 72 aL and 72 aR are provided, the guide members 80L and 80R have the protrusions 84 protruding upward from the oil suction ports 72 a, the separator main bodies 87 of the oil separators 86L and 86R are disposed on the upper end portions of the protrusions 84, and the guide members 80L and 80R are sandwiched between the oil separators 86L and 86R (the separator main body 87) and the pump housings 52L and 52R.According to the configuration, when the oil separators 86L and 86R are disposed at and supported by the upper end portions of the protrusions 84 of the guide members 80L and 80R, the setting of the oil separators 86L and 86R can be easily adjusted by changing the shape or the like of the guide members 80L and 80R separately from the pump housings 52L and 52R.In the engine 7, the oil separators 86L and 86R are made of a metal, and the guide members 80L and 80R are made of a resin having a specific gravity lower than that of the oil separators 86L and 86R.According to the configuration, the oil separators 86L and 86R are made of a metal to increase strength, and the oil separators 86L and 86R may be made compact to be able to approach the crankshaft 11 more easily. In addition, when the guide members 80L and 80R protruding upward from the oil suction ports 72 aare made of a resin, the guide members 80L and 80R can be weight-reduced with large volumes, and weight reduction of the engine 7 can be achieved.In the engine 7, the oil suction ports 72 aL and 72 aR of the scavenging pumps 51L and 51R are attached to the inner wall (the curved wall 22) of the crankcase 20 on the first plane (the pump attachment surfaces 23 c), and the rear attachment portion 68R located behind the suction ports 72 aL and 72 aR of the scavenging pumps 51L and 51R is attached to the inner wall (the rear curved wall 27) of the crankcase 20 on the second plane (the attachment surface 68 d) that is displaced below the first plane.According to the configuration, since the rear portions of the scavenging pumps 51L and 51R are attached to the inner wall of the crankcase 20 in the region shifted with respect to the oil suction ports 72 aL and 72 aR of the scavenging pumps 51L and 51R in the stepped shape, the rear portions of the scavenging pumps 51L and 51R can be attached to the crankcase 20 in the region below the transmission 16 bypassing the same behind the crankshaft 11 while the oil suction ports 72 aL and 72 aR are disposed near the crankshaft 11. Since the opening area of the oil suction ports 72 aL and 72 aR of the scavenging pumps 51L and 51R can thus be increased, the oil discharge amount by the scavenging pumps 51L and 51R can be increased, and the oil resistance occurring in the crankcase 20 can be reduced.Although the present invention is not limited to the embodiment and, for example, in the embodiment, the present invention is applied to a four-cylinder V engine, the application of the present invention is not limited thereto. That is, the present invention can be applied to various internal combustion engines having closed crankcases. In addition, the transmission may be applied to a separate internal combustion engine.The internal combustion engine of the embodiment can be applied to a saddle-riding vehicle other than a motorcycle. All vehicles on which a rider sits on the vehicle body are enclosed as a saddle-riding vehicle, and in addition to a motorcycle (including a motorized bicycle and a scooter type vehicle), a three-wheeled vehicle (including a vehicle having two front wheels and one rear wheel in addition to a vehicle having one front wheel and two rear wheels) or a four-wheeled vehicle (a four-wheel buggy or the like) may also be included.The invention can be applied to a vehicle having an electric motor as the engine. In addition, it may be applied to a vehicle other than the saddle-riding vehicle (a passenger car, a bus, a truck, or the like).Further, although the internal combustion engine of the embodiment is applied to the vehicle, the present invention is not limited to the vehicle and can be applied to various transport facilities such as airplanes, ships, or the like, various vehicles, and moving objects such as construction machines, industrial machines, or the like. Further, the present invention can be widely applied to, for example, a hand-held lawn mower, a cleaning machine, or the like as long as it is an engine-equipped apparatus other than the vehicle.

Claims

An internal combustion engine comprising: a crankcase (20); scavenge pumps (51L, 51R) for drawing engine oil flowing downward from the crankcase (20); oil separators (86L, 86R) attached to pump housings (52L, 52R) of the scavenge pumps (51L, 51R) and configured to drip the engine oil carried around a crankshaft (11) toward oil suction ports (72aL, 72aR) of the scavenge pumps (51L, 51R); and guide members (80L, 80R) attached to the oil suction ports (72aL, 72aR), the guide members (80L, 80R) having protrusions (84), The oil separators (86L, 86R) are disposed at upper end portions of the protrusions (84), and the guide members (80L, 80R) are sandwiched between the oil separators (86L, 86R) and the pump housings (52L, 52R), protruding upward from the oil suction ports (72aL, 72aR), characterized in that the oil separators (86L, 86R) are made of a metal, and the guide members (80L, 80R) are made of a resin having a specific gravity lower than that of the oil separators (86L, 86R).The internal combustion engine according to claim 1, wherein the oil separators (86L, 86R) include: fastening parts (87a) fixed to the pump housings (52L, 52R) of the scavenge pumps (51L, 51R); and a superposition part (87b) that superimposes the oil suction ports (72aL, 72aR) as viewed in a plan view.The internal combustion engine according to claim 1 or 2, wherein the oil separators (86L, 86R) are disposed in a position in which edge portions (87b) are located near the crankshaft (11) when viewed in an axial direction of the crankshaft (11), and the edge portions (87b) include a plurality of bent portions (89a, 89b, 89c) bent toward the crankshaft (11) when viewed in the axial direction.The internal combustion engine according to claim 3, wherein the plurality of bent portions (89a, 89b, 89c) have different positions and angles as viewed in the axial direction.The internal combustion engine according to any one of claims 1 to 4, comprising the guide members (80L, 80R) attached to the oil suction ports (72aL, 72aR) and configured to narrow down an oil flow passage.The internal combustion engine according to any one of claims 1 to 5, wherein the oil suction ports (72aL, 72aR) of the scavenge pumps (51L, 51R) are attached to an inner wall (22) of the crankcase (20) on a first plane (23c), and a rear attachment portion (68R) located behind the oil suction ports (72aL, 72aR) of the scavenge pumps (51L, 51R) is attached to a rear inner wall (27) of the crankcase (20) on a second plane (68d) shifted below the first plane (23c).

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