JP4030401B2 - 4-cycle direct injection engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a four-cycle direct injection engine that directly injects fuel into a combustion chamber.
[0002]
[Prior art]
Conventionally, such a four-cycle direct injection engine is already known, for example, from Patent Document 1.
[0003]
[Patent Document 1]
Japanese Patent Publication No. 5-71767
[0004]
[Problems to be solved by the invention]
The conventional four-cycle direct injection engine is configured such that fuel is injected sideways into the combustion chamber, and it is difficult to concentrate the fuel spray at the center of the combustion chamber and perform lean combustion.
[0005]
The present invention has been made in view of such circumstances, and an object of the present invention is to provide a four-cycle direct-injection engine in which lean combustion is possible and fuel consumption can be reduced, and the cylinder head is downsized. To do.
[0006]
[Means for Solving the Problems]
  In order to achieve the above object, according to a first aspect of the present invention, there is provided a four-cycle direct injection engine in which fuel is directly injected into a combustion chamber. The cylinder head is arranged so as to be openable and closable in a V-shaped arrangement on the projection to the cylinder axis,Placed coaxiallyAn injection valve is attached to the cylinder head between the intake valve and the exhaust valve so as to inject fuel directly into the combustion chamber.RespectivelyInterlocked and connected to be arranged between the intake valve and the exhaust valveIntake side and exhaust sideThe rocker arm is fixed to the cylinder head with an axis perpendicular to the virtual plane.Intake side and exhaust sideEach rocker shaft pivotsThe intake side and exhaust side rocker shafts are arranged on the cylinder block on one side in the axial direction away from the injection valve.Acts in the axial direction following the rotation of the camshaft to which rotational power is transmitted from the crankshaftA pair of drive rods are linked and connected to the other ends of the intake side and exhaust side rocker arms, respectively, and the exhaust side rocker arms are closer to the drive rod side than the axis of the injection valve in the direction along the axis of the rocker shaft. Is offset andThe pair of drive rods are connected to both rocker shafts.One side in the axial directionAt the position corresponding to the edgeBothAs you move closer to the rocker arm, the distance between each other is gradually reduced.And both of the drive rods areIt is arranged to be inclined toward the cylinder axis toward the rocker arm.
[0007]
  According to such a configuration of the first aspect of the present invention, the fuel injected from the injection valve can be collected near the center of the combustion chamber, so that lean combustion is possible and fuel consumption can be reduced. In addition, among the valve gears for driving the intake valve and the exhaust valve, only the rocker arm and the rocker shaft that swings and supports the rocker arm can be disposed on the cylinder head, thereby making it possible to reduce the size of the cylinder head.In addition, since the pair of drive rods are arranged with the mutual distance gradually narrowed as approaching the rocker arm at a position corresponding to one end of both rocker shafts, it is possible to set the distance between both rocker shafts to be narrower, It is possible to reduce the size of the cylinder head in a direction along a straight line connecting the axes of both rocker shafts.
[0009]
  AlsoClaim2The invention described is the above claim.1In addition to the configuration of the invention described above, an ignition plug is attached to the cylinder head on the side opposite to the two drive rods with respect to the injection valve, and according to such a configuration, the rocker arm and the drive plug are linked and connected. By arranging the part, it is possible to increase the degree of freedom in the arrangement of the spark plug by arranging the spark plug so as to avoid the part with less free space, and the spark plug can be brought closer to the fuel injection valve. Therefore, combined with the fact that fuel spray from the injection valve can be collected near the center of the combustion chamber, fuel consumption can be further reduced by layered dilution.
[0010]
  And claims3In addition to the configuration of the invention described in the first aspect, the invention described in the present invention has an odd number of intake valves and exhaust valves arranged in the cylinder head as a whole, and the smaller number of the intake valves and the exhaust valves. The spark plug is attached to the cylinder head so as to be aligned with the valve, and according to such a configuration, the spark plug is arranged by effectively utilizing the empty space generated around the valve on the side where the number of arrangement is small. Therefore, the degree of freedom in the arrangement of the spark plug can be increased, and the spark plug can be brought closer to the fuel injection valve, which is combined with the fact that the fuel spray from the injection valve can be collected near the center of the combustion chamber. The fuel consumption can be further reduced by the layered dilution.
[0011]
  Further claims4According to the invention described above, in addition to the configuration of the invention according to claim 1, the injection valve is configured to directly inject fuel into the combustion chamber together with the compressed air, and supplies the compressed air to the injection valve. A part of the path is provided in the cylinder head on the other end side of the rocker shaft. According to such a configuration, the fuel is further atomized and injected into the combustion chamber, thereby improving the combustibility and improving the fuel efficiency. Further improvement can be achieved, and a part of the compressed air supply path for guiding the compressed air is provided in the cylinder head at the other end of the rocker shaft, so that a passage is formed in the cylinder head while avoiding an increase in the size of the cylinder head. Thus, an increase in the number of parts can be prevented.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on one embodiment of the present invention shown in the accompanying drawings.
[0013]
1 to 10 show an embodiment of the present invention, FIG. 1 is a partially longitudinal side view of an engine, FIG. 2 is a view taken along line 2-2 in FIG. 1 with a head cover removed, 3 is a sectional view taken along line 3-3 in FIG. 2, FIG. 4 is a sectional view taken along line 4-4 in FIG. 3, FIG. 5 is a sectional view taken along line 5-5 in FIG. FIG. 7 is a sectional view taken along line 7-7 in FIG. 2, FIG. 8 is a sectional view taken along line 8-8 in FIG. 7, FIG. 9 is a sectional view taken along line 9-9 in FIG. It is a vertical side view of the engine along the 10-10 line of FIG.
[0014]
First, in FIG. 1, an engine body 11 of an overhead valve type four-cycle water-cooled single cylinder direct injection engine includes a crankcase 12, a cylinder block 13 coupled to the crankcase 12, and the crankcase 12. A cylinder head 14 that is coupled to the cylinder block 13 on the opposite side and a head cover 15 that is coupled to the cylinder head 14 on the opposite side of the cylinder block 13 are provided. Mounted on vehicles such as motorcycles.
[0015]
2 to 4 together, the piston 17 slidably fitted in the cylinder bore 16 provided in the cylinder block 13 is supported by the crankshaft 10 rotatably supported by the crankcase 12 (FIG. 1). A combustion chamber 19 is formed between the cylinder block 13 and the cylinder head 14 so as to face the top of the piston 17 through a connecting rod 18 and a crank pin (not shown).
[0016]
The cylinder head 14 has first and second intake ports 20, 21 that open on the upper side surface of the cylinder head 14 with one end individually opened on the ceiling wall 19 a of the combustion chamber 19 and the other end connected in common. Are provided in parallel, and an exhaust port 22 having one end opened in the ceiling wall 19a of the combustion chamber 19 and the other end opened in the lower side surface of the cylinder head 14 is provided.
[0017]
Open ends of the first and second intake ports 20 and 21 to the combustion chamber 19 are opened and closed by first and second intake valves 27 and 28, respectively. Open ends of the exhaust port 22 to the combustion chamber 19 are exhaust valves. It is opened and closed at 29. That is, the cylinder head 14 is provided with an odd number of intake valves 27, 28 and exhaust valves 29 as a whole so as to be able to open and close, and the first and second intake valves 27, 28 are fixed to the cylinder head 14. Are respectively slidably fitted to the guide cylinders 30 and are respectively fixed to the upper ends of the intake valves 27 and 28 protruding from the guide cylinders 30 and the valve springs 32 between the cylinder heads 14. Are provided, and both intake valves 27 and 28 are biased in the valve closing direction by the spring force exerted by the valve springs 32. The exhaust valve 29 is slidably fitted to a guide cylinder 33 fixed to the cylinder head 14, and a valve spring is interposed between the retainer 34 fixed to the upper end portion of the exhaust valve 29 protruding from the guide cylinder 33 and the cylinder head 14. 35 is provided, and the exhaust valve 29 is urged in the valve closing direction by the spring force exerted by the valve spring 35.
[0018]
In addition, the operation axes of the intake valves 27 and 28, that is, the axes of the guide cylinders 30 ... are arranged in parallel so as to overlap each other on the projection on the virtual plane including the cylinder axis C perpendicular to the axis of the crankshaft 10. Then, the operation axes of the intake valves 27 and 28 and the operation axis of the exhaust valve 29, that is, the axis of the guide cylinder 33 are V-shaped on the projection onto the virtual plane, and the intake valves 27 and 28 and An exhaust valve 29 is disposed on the cylinder head 14 so as to be opened and closed.
[0019]
By the way, on the projection onto the plane orthogonal to the cylinder axis C, the first intake port 20 and the exhaust port 22 are arranged on both sides of the cylinder axis C, and a straight line L1 connecting the first intake port 20 and the exhaust port 22 is shown. The second intake port 21 is arranged on one side of the cylinder axis C on another straight line L2 that is substantially orthogonal to the first intake port 20 so as to be aligned with the first intake port 20. Further, the position corresponds to the first intake port 20 on one end side along the parallel direction of the intake ports 20 and 21 and is shifted from the center of the combustion chamber 19 and has a smaller number than the intake valves 27 and 28. A spark plug 26 facing the combustion chamber 19 is attached to the cylinder head 14 at a position aligned with the exhaust valve 29.
[0020]
Fuel is directly injected into the combustion chamber 19 by an injector 25 having an axis parallel to the cylinder bore 16, that is, an axis parallel to the cylinder axis C, and disposed between the exhaust valves 27 and 28 and the exhaust valve 29 in the cylinder head 14. In this embodiment, the injector 25 is disposed on the cylinder head 14 so as to be coaxial with the cylinder axis C.
[0021]
That is, the injector 25, the pair of intake ports 20 and 21, the exhaust port 22 corresponding to the second intake port 21, and the spark plug 26, the injector 25 is connected to both the intake ports 20 and 21, the exhaust port 22 and the spark plug. 26 is disposed in the cylinder head 14 so as to be surrounded by 26.
[0022]
In FIG. 5, the ceiling of the combustion chamber 19 around the open end to the combustion chamber 19 of the first intake port 20 arranged on one end side in the parallel direction among the first and second intake ports 20, 21 arranged in parallel with each other. The wall 19 a has a guide wall 142 that guides the intake air flowing into the combustion chamber 19 from the first intake port 20 so as to flow around the spark plug 26 at a position corresponding to the first intake port 20. Provided.
[0023]
Referring also to FIG. 6, a cavity 143 is provided at the center of the surface of the piston 17 facing the combustion chamber 19. A projection 144 projecting toward the piston 17 is formed on the ceiling wall 19a of the combustion chamber 19, and the spark plug 26 has a tip projecting from the projection 144 into the combustion chamber 19 disposed below the tip of the injector 25. In this way, it is attached to the cylinder head 14. Moreover, the cavity 143 is formed so as to become deeper toward the spark plug 26 side.
[0024]
With further reference to FIGS. 7 to 9, the first and second intake valves 27, 28 and the exhaust valve 29 are opened and closed by a valve operating device 38. A camshaft 41 that rotates with intake and exhaust side cams 39, 40, an intake side first rocker arm 42 that swings in response to the intake side cam 39, and a swing that is driven by the exhaust side cam 40. The exhaust-side first rocker arm 43 that moves, the intake-side second rocker arm 44 having a pair of pressing arm portions 44 a and 44 b that contact the first and second intake valves 27 and 28 on one end side, and the exhaust valve 29 are in contact with each other. The suction side first rocker arm 4 and the exhaust side second rocker arm 45 having a pressing arm portion 45a on one end side and the swinging motion of the suction side first rocker arm 42 are transmitted to the suction side second rocker arm 44. , 44 and the exhaust side first rocker arm 43 are provided between the exhaust side first and second rocker arms 43 and 45 so as to transmit the swinging motion of the exhaust side first rocker arm 43 to the exhaust side second rocker arm 45. The exhaust side drive rod 47 is provided.
[0025]
Between the cylinder head 14 and the head cover 15, the intake side and the exhaust side second rocker arms 44 and 45 of the valve operating device 38 and the intake side and the exhaust side second rocker arms 44 and 45 are pivotally supported. A first valve chamber 48 is formed in which the upper side of the side second rocker shafts 58 and 59 and the intake side and exhaust side drive rods 46 and 47 are accommodated and arranged, and the crankcase 12, the cylinder block 13, and the cylinder head 14. The second valve chamber 49 for accommodating the remaining portion of the valve operating device 38 is formed so as to extend in parallel to the cylinder axis C on the opposite side of the cylinder axis C from the side where the spark plug 26 is disposed. Is done.
[0026]
In order to lubricate a portion of the valve operating device 38 accommodated in the first valve operating chamber 48, the head cover 15 is provided with an oil ejection hole 36, and a portion accommodated in the first valve operating chamber 48. The oil having been lubricated is returned to the oil pan 12a (see FIG. 1) formed in the lower portion of the crankcase 12 through the second valve operating chamber 49.
[0027]
The intake-side and exhaust-side first rocker arms 42, 43 have rollers 54, 55 that are in rolling contact with the intake-side and exhaust-side cams 39, 40 from the cylinder head 14 side, and are parallel to the camshaft 41. And is supported by an intake side and exhaust side first rocker shafts 56 and 57 provided between the cylinder block 13 and the cover 50 so as to be swingable. These intake-side and exhaust-side first rocker arms 42, 43 are integrally provided with saddle-shaped pressing portions 42a, 43a located on the opposite side of the rollers 54, 55 so as to open to the cylinder head 14 side. .
[0028]
The camshaft 41 of the valve gear 38 is disposed in the cylinder block 13 so as to be accommodated in the second valve chamber 49, and the cylinder block 13 and the outer surface of the second valve chamber 49 are arranged. Both ends of a camshaft 41 having an axis parallel to the crankshaft 10 are rotatably supported via ball bearings 51 and 51 on the cover 50 fastened to the cylinder block 13 as formed.
[0029]
Moreover, the oil supply passage 37 for supplying lubricating oil to the sliding contact portions of the intake side and exhaust side cams 39, 40 and the intake side first rocker arm 42 and the exhaust side first rocker arm 43 is provided on the camshaft 41. Is provided.
[0030]
A first driven sprocket 52, a first drive sprocket 60 (see FIG. 1), and an endless cam chain are used to transmit the power from the crankshaft 10 to the second valve chamber 49 by decelerating to 1/2. 53 is accommodated, the first driven sprocket 52 is coupled to the camshaft 41 in a relatively non-rotatable manner, the first drive sprocket 60 is coupled to the crankshaft 10 in a relatively non-rotatable manner, and the cam chain 53 is coupled to the first drive sprocket 60. And wound around the first driven sprocket 52.
[0031]
  The intake side and exhaust side drive rods 46 and 47 extend from the first valve operating chamber 48 to a part of the second valve operating chamber 49.As shown in FIG.So that the mutual distance on the cylinder head 14 side is narrow.(In other words, the mutual distance is gradually narrowed as the rocker arms 44 and 45 are approached.) Further, as shown in FIG. 9, the rocker arms 44 and 45 are inclined toward the cylinder axis C side.Be placed. The spherical end portions on one end side of the intake side and exhaust side drive rods 46, 47 are fitted to the pressing portions 42a, 43a of the intake side and exhaust side first rocker arms 42, 43 so as to be able to swing, so that the intake side and exhaust side drive are performed. The spherical end portions on the other end side of the rods 46 and 47 are fitted to the pressure receiving portions 44c and 45b of the intake side and exhaust side second rocker arms 44 and 45 so as to be swingable.
[0032]
In the first valve operating chamber 48, the cylinder head 14 supports intake side and exhaust side second rocker shafts 58 and 59 having axes parallel to the camshaft 41 so as to be arranged on both sides of the injector 25. The pair of pressing arm portions 42a which are bifurcated so as to be linked and connected to both intake valves 28 and 29 by contacting the upper ends of the first and second intake valves 28 and 29. , 42b on one end side, the intake side second rocker arm 42 is supported by the intake side second rocker shaft 58 so as to be swingable, and is in contact with the upper end of the exhaust valve 29. An exhaust side second rocker arm 43 having an arm portion 45a on one end side is supported by an exhaust side second rocker shaft 59 so as to be swingable.
[0033]
In addition, a flange-shaped pressure receiving portion 44c opened to the cylinder block 13 side is integrally provided at the other end of the intake side second rocker arm 44 on the side opposite to the pressing arm portions 44a and 44b with respect to the intake side second rocker shaft 58. The exhaust-side second rocker shaft 59 is integrally provided with a flange-shaped pressure receiving portion 45b that opens on the cylinder block 13 side on the opposite side of the pressing arm portion 45a with respect to the exhaust-side second rocker shaft 59.
[0034]
The other end portions of the intake side and exhaust side second rocker arms 44 and 45, that is, pressure receiving portions 44c and 45b, are disposed between the one end portions of the intake side and exhaust side second rocker shafts 58 and 59, and the intake side and exhaust side The drive rods 46 and 47 are linked and connected to the other end portions of the intake side and exhaust side second rocker arms 44 and 45 between the one end portions of the intake side and exhaust side second rocker shafts 58 and 59.
[0035]
In such a valve operating system 38, the intake side first rocker arm 42 is swung by the intake side cam 39 in accordance with the rotation of the camshaft 41 to which rotational power is transmitted from the crankshaft at a reduction ratio of 1/2. As a result, the intake side drive rod 46 operates in the axial direction thereof, and the intake side second rocker arm 44 swings accordingly, thereby opening and closing the first and second intake valves 27 and 28, and the exhaust side cam 40. As a result, the exhaust-side first rocker arm 43 swings to operate the exhaust-side drive rod 47 in the axial direction, and the exhaust-side second rocker arm 45 swings accordingly to drive the exhaust valve 29 to open and close. become.
[0036]
Incidentally, the injector 25 is supplied with compressed air from a reciprocating air pump 61 that reciprocates the piston 66 in a direction parallel to the cylinder axis C. The air pump 61 is provided in the cylinder head 14. The cylinder block 13 is disposed on the side corresponding to the exhaust port 24 formed. Moreover, the cylinder block 13 is formed with a working chamber 62 disposed below the cylinder bore 16 so as to be connected to the second valve chamber 49 in a substantially L shape within a plane perpendicular to the cylinder axis C. The air pump 61 is disposed below the second valve operating chamber 49 in a connecting portion of the second valve operating chamber 49 and the working chamber 62.
[0037]
Referring also to FIG. 10, the pump case 63 of the air pump 61 is formed integrally with the cylinder block 13 in the shape of a bottomed cylinder having an axis parallel to the cylinder axis C and opening the cylinder head 14 side. A lid member 64 that tightly closes the cylinder head 14 side opening of the pump case 63 is fastened to the cylinder block 13. Moreover, the lid member 64 is coupled to the pump case 63 on the same plane as the coupling surface 87 of the cylinder block 13 and the cylinder head 14.
[0038]
The piston 66 is slidably fitted to the pump case 63, and is arranged between the one end of the piston 66 and the lid member 64 on the cylinder head 14 side so as to generate compressed air corresponding to volume contraction. A pump chamber 65 is formed, and an atmospheric pressure chamber 88 disposed on the oil pan 12 a side is formed between the other end of the piston 66 and the closed end of the pump case 63.
[0039]
On the other hand, a cylindrical bearing member 69 having an axis parallel to the axis of the camshaft 41 and passing through the axis of the piston 66 is disposed in the working chamber 62, and the bearing member 69 is attached to the cylinder block 13. The plurality of projecting, for example, four fastening bosses 70 are fastened by bolts 71. In addition, the cover 72 that forms the outer side surface of the working chamber 62 is fastened to the cylinder block 13, and the bolts 71 can be tightened and loosened when the cover 72 is opened.
[0040]
A pump drive shaft 73 is coaxially inserted in the bearing member 69, and a roller bearing 74 is interposed between one end of the bearing member 69 and the pump drive shaft 73, and the other end of the bearing member 69 and the pump drive. A ball bearing 75 is interposed between the shafts 73. That is, the pump drive shaft 73 is rotatably supported by the bearing member 69 fastened to the cylinder block 13.
[0041]
The portion projecting from one end of the bearing member 69 transmits power from the camshaft 41 to the pump drive shaft 73 via the power transmission means 89. The power transmission means 89 is a pump drive shaft. 73, a second driven sprocket 78 fixed to 73, a second driven sprocket 79 integral with the first driven sprocket 52 coupled to the camshaft 41, and an endless shape wound around the second driven and driven sprockets 78, 79. Chain 80.
[0042]
The pump drive shaft 73 is connected to the piston 66 of the air pump 61 via a Scotch-yoke crank 84, and the Scotch-yoke crank 84 is slidably fitted to the piston 66. Further, the tip of an eccentric shaft 73a protruding from the eccentric position of one end of the pump drive shaft 73 is connected. Thus, as the pump drive shaft 73 rotates with the power transmitted from the camshaft 41, the eccentric shaft 73 a rotates around the axis of the pump drive shaft 73, and the piston 66 of the air pump 61 moves in the volume of the pump chamber 65. Is reciprocally driven in the axial direction in the pump case 63 so as to increase or decrease.
[0043]
The piston 66 is provided with a slide hole 67 that is arranged along a plane of the diameter of the piston 66 and perpendicular to the axis of the camshaft 41, and the slide piece 68 can slide in the slide hole 67. Fitted. Further, the eccentric shaft 73 a is integrally projected at one end of the pump drive shaft 73.
[0044]
Thus, the pump case 63 is provided with an opening 76 into which one end of the pump drive shaft 73 is inserted. The piston 66 has an eccentric shaft 73 a corresponding to the rotation of the pump drive shaft 73. An insertion hole 77 into which the eccentric shaft 73a is inserted so as to allow movement in the direction along the direction of the sliding hole 67 is provided so as to communicate with the central portion in the longitudinal direction of the sliding hole 67.
[0045]
Through holes 81 and 82 are provided in both sides of the bearing member 69 at the center between the ball bearing 75 and the roller bearing 74, and the bearing member 69 has a working chamber at a position corresponding to the one through hole 81. An oil guide 83 for guiding a part of the oil falling into 62 between the bearing member 69 and the pump drive shaft 73 is integrally provided. That is, a passage 134 provided in the cylinder head 14 is provided in the cylinder head 14 so as to guide a part of the oil accumulated in the lower part in the first valve operating chamber 48, and the passage 134 is opened to the working chamber 62. The passage 135 is provided in the cylinder block 13, and the oil guide 83 is provided integrally with the bearing member 69 so that the oil falling from the passage 135 is guided to the through hole 81. A part of the oil introduced between the bearing member 69 and the pump drive shaft 73 is used for lubrication of the roller bearing 74 and the ball bearing 75, and the remaining part falls from the through hole 82 to the lower part in the working chamber 62. The oil accumulated in the lower portion of the working chamber 62 is returned to the oil pan 12a side from the return passage 136 provided in the cylinder block 13 so as to communicate with the lower portion of the working chamber 62.
[0046]
A water pump 90 having a rotation axis coaxial with the pump drive shaft 73 is attached to the cylinder block 13 on the side opposite to the air pump 61 with respect to the bearing member 69, and includes the cylinder drive line 73 and the pump drive shaft 73. Air pump 61 and water pump 90 are arranged at positions that are plane-symmetric with respect to orthogonal plane PL.
[0047]
The pump housing 91 of the water pump 90 includes a housing main body 92 in which a dish-shaped portion 92b is integrally connected to an open end of a bottomed cylindrical portion 92a closed on the pump drive shaft 73 side, and an open end of the housing main body 92. The pump cover 93 is configured to be closed, and the pump cover 93 is fastened to the cylinder block 13 so that the outer peripheral portion of the open end of the housing main body 92 is sandwiched between the cylinder block 13.
[0048]
Both ends of a pump shaft 94 that is coaxial with the pump drive shaft 73 are rotatably supported at the central portion of the closed end of the bottomed cylindrical portion 92a and the central portion of the pump cover 93, and rotate integrally with the pump shaft 94. Thus, the inner magnet 96 is fixed to the rotor 95 inserted into the bottomed cylindrical portion 92a. On the other hand, a rotating member 97 having a cylindrical portion 97a that coaxially surrounds the bottomed cylindrical portion 92a of the housing main body 92 is fixed to the other end portion of the pump drive shaft 73 protruding from the other end of the bearing member 69. The outer magnet 98 is fixed to the inner surface of the cylindrical portion 97a. As a result, the rotor 95 rotates with the pump shaft 94 as the rotating member 97 rotates with the pump drive shaft 73.
[0049]
Meanwhile, a vortex chamber 99 is formed between the housing main body 92 and the pump cover 93, and an impeller 100 accommodated in the vortex chamber 99 is provided in the rotor 95.
[0050]
The pump cover 93 is provided with a plurality of suction ports 101 opening in the center of the vortex chamber 97, and the cooling water sucked into the vortex chamber 99 from the suction ports 101 is pressurized by the rotation of the impeller 100. Thus, the cooling water discharged from the water pump 90 passes through the block side water jacket 102 provided in the cylinder block 13 and the head side water jacket 103 provided in the cylinder head 14 through the block side water jacket 102. The state in which the cooling water discharged from the head-side water jacket 103 is guided to a radiator (not shown) and the state in which the radiator and the like are bypassed and returned to the suction port 101... The thermostat 104 is switched by the thermostat 104, and the thermostat housing 105 of the thermostat 104 is formed integrally with the pump cover 93 of the water pump 90.
[0051]
In the upper side wall of the pump case 63 in the air pump 61, an oil introduction hole 85 for guiding a part of the oil flowing through the second valve valve chamber 49 into the pump case 63 for lubrication is provided in the second valve chamber 49. Provided to communicate. By the way, due to the rotation in the second valve chamber 49, the intake side cam 39 and the exhaust side cam 40 of the camshaft 41 lift up a part of the oil flowing in the second valve chamber 49 and by the action of centrifugal force. The oil is separated and scattered, and a part of the oil supplied from the oil supply passage 37 is separated and scattered by the action of centrifugal force. The camshaft 41 and the oil are introduced so that the separated oil splash is guided to the oil introduction hole 85. The relative position of the introduction hole 85 is set.
[0052]
By the way, the width of the portion corresponding to the valve operating device 38 in the second valve operating chamber 49 is formed larger than the other portions, and the intake side cam 39 and the exhaust side cam 40 of the camshaft 41 are formed. A projecting wall 86 that surrounds a portion corresponding to a semicircular shape projects integrally with the cylinder block 13 so as to face the oil flow direction 137 in the second valve chamber 49, and the air pump The oil return hole 85 of 61 is arranged at a position immediately upstream of the protruding wall 86 along the oil circulation direction 137. That is, the protruding wall 86 functions to guide the oil that has flowed through the second valve operating chamber 49 to the oil introduction hole 85.
[0053]
Moreover, the oil return hole 85 is attached to the outer periphery of the piston 66 and opens to the inner periphery of the pump case 63 on the atmospheric pressure chamber 88 side than the piston ring 138 that is in sliding contact with the inner periphery of the pump case 63. Regardless of the axial movement of the piston 66, the oil return hole 85 always communicates with one end of the sliding hole 67 provided in the piston 66. Further, on the outer periphery of the piston 66, there are provided a pair of grooves 139 connecting the end portion of the piston 66 on the atmospheric pressure chamber 88 side and both ends of the sliding hole 67, and are introduced into the pump case 63 from the oil return hole 85. A part of the oil used is used for lubrication between the piston 66 and the pump case 63, and the remaining part flows to the atmospheric pressure chamber 88 side through the grooves 139. In addition, the grooves 139... Also serve to prevent the pumping action of the sliding piece 68 in the Scotch-yoke type crank 84 by allowing oil in the sliding hole 67 to escape.
[0054]
Thus, the oil that has flowed into the atmospheric pressure chamber 88 flows from the opening 76 toward the working chamber 62, and further flows from the return passage 136 toward the oil pan 12a.
[0055]
With particular attention to FIG. 9, the injector 25 includes a first injection valve 107 that is attached to the head cover 15 so as to inject fuel, and a cylinder head 14 that directly injects fuel together with compressed air into the combustion chamber 19. The second injection valve 108 attached to the second injection valve 108 is connected coaxially, and the second injection valve 108 has a nozzle 108 a that enters the combustion chamber 19.
[0056]
The cylinder head 14 has a fitting hole 109 for fitting the nozzle 108a in an airtight manner and an insertion cylinder 110 having an inner diameter larger than the fitting hole 109 and coaxially connected to the fitting hole 109. The second injection valve 108 is provided in an annular shape formed between the fitting hole 109 and the insertion cylinder 110 while the nozzle 108a is fitted in the fitting hole 109 in an airtight manner. It is inserted into the insertion tube 110 from the head cover 15 side until it contacts the stepped portion 111 via the wave spring washer 123.
[0057]
Thus, the tip of the second reflection valve 108, that is, the nozzle 108 a is inserted into the cavity 143 of the piston 17 at the top dead center while being inserted into the insertion cylinder 110 until it abuts on the stepped portion 111. The tip of the spark plug 26 is positioned below the nozzle 108a in the cavity 143 when the piston 17 is at the top dead center.
[0058]
A conductor connecting portion 108 b provided at the rear portion of the second injection valve 108 is disposed in a notch 110 a provided at the rear end of the insertion tube 110, and is a pair led out from the conductor connection portion 108 b outside the insertion tube 110. Are led out through the grommet 113 sandwiched between the mating surfaces of the cylinder head 14 and the head cover 15.
[0059]
On the other hand, a cylindrical injector housing 114 that fits and holds the first injection valve 107 on the head cover 15 and also functions as a positioning portion that positions and clamps the second injection valve 108 with the cylinder head 14. Are integrally formed, and when the head cover 15 is coupled to the cylinder head 14, the tip of the injector housing 114 abuts against the rear end of the second injection valve 108. In addition, a clamping plate 115 that clamps the rear end portion of the first injection valve 107 between the injector housing 114 and the injector housing 114 is fastened to the rear end of the injector housing 114.
[0060]
The first injection valve 107 includes a wiring connector 107a at the rear thereof, and the first injection valve 107 is connected to the head cover 15 by sandwiching the rear end portion of the first injection valve 107 between the injector housing 114 and the holding plate 115. The wiring connector 107 a is disposed so as to face the outside of the head cover 15 when attached to the head cover 15.
[0061]
By the way, an annular fuel chamber 116 communicating with the first injection valve 107 is formed between the injector housing 114 and the first injection valve 107, and a pair of seal members 117 sandwiching the fuel chamber 116 from both sides. 118 is interposed between the first injection valve 107 and the injector housing 114.
[0062]
In addition, the head cover 15 is directly provided with a fuel supply passage 119 leading to the fuel chamber 116, and a hose 120 for guiding fuel from a fuel supply source (not shown) is connected to the fuel supply passage 119 via a joint 121.
[0063]
An annular air chamber 122 communicating with the second injection valve 108 is formed in the injector housing 114 between the front end portion of the first injection valve 107 and the rear end portion of the second injection valve 108. The compressed air from the air pump 61 is supplied to the air chamber 122.
[0064]
2 and 10, the lid member 64 of the air pump 61 is provided with a suction pipe 124 to which a hose that guides air from an air cleaner (not shown) is connected. The suction pipe 124 is connected to the lid member 64. The pump chamber 65 is connected via a built-in reed valve (not shown).
[0065]
The lid member 64 has a built-in poppet valve 125 that opens as the pressure in the pump chamber 65 increases. Compressed air discharged from the air pump 61 passes through the poppet valve 125 and the compressed air supply passage 126. Via the air chamber 122.
[0066]
The compressed air supply path 126 is connected to the lid member 64 so as to be connected to the poppet valve 125, and is connected to the tube member 127 connected to the cylinder head 14 at the other end. A passage 128 is provided directly on the head 14, and a passage 129 is provided on the head cover 15 so as to communicate with the passage 128 and the air chamber 122.
[0067]
In addition, the passage 128 provided directly in the cylinder head 14 is opposite to the side where the drive rods 46 and 47 of the valve operating device 38 are arranged, that is, the intake side and the exhaust side arranged in the first valve operating chamber 48. Two rocker shafts 58 and 59 are provided on the cylinder head 14 on the other end side. Moreover, a part of the passage 128 passes through the vicinity of the exhaust port 24, and in particular, in the vicinity of the exhaust port 24, the head side water jacket 103 is disposed between the exhaust port 24 and the cylinder block 13. On the other hand, the passage 128 is set so as to pass through the opposite side of the head side water jacket 103 with respect to the exhaust port 24.
[0068]
Further, both ends of a cylindrical knock pin 130 straddling the mating surface of the cylinder head 14 and the head cover 15 are inserted into the cylinder head 14 and the head cover 15, and constitute a part of the compressed air passage 126 to form the cylinder head 14 and the head cover 15. The passages 128 and 129 provided directly in the communication are communicated via the knock pin 130. In addition, an O-ring 133 surrounding the knock pin 130 is sandwiched between the mating surfaces of the cylinder head 14 and the head cover 15.
[0069]
An orifice 131 is formed in the knock pin 130, and a relief valve 132 connected to the passage 128 upstream of the orifice 131 is attached to the cylinder head 14.
[0070]
Next, the operation of this embodiment will be described. The first and second intake valves 27, 28 and the exhaust valve 29 are arranged in a virtual plane in which the operation axis of the valves 27, 28; 29 includes the cylinder axis C. The second injection valve 108 having an axis parallel to the cylinder axis C is disposed directly in the combustion chamber 19 so that the cylinder head 14 can be opened and closed. Since it is attached to the cylinder head 14 between the intake valves 27, 28 and the exhaust valve 29 so as to inject fuel, the fuel injected from the second injection valve 108 can be collected near the center of the combustion chamber 19, Lean combustion is possible and fuel consumption can be reduced. Moreover, since the second injection valve 108 directly injects the fuel together with the compressed air into the combustion chamber 19, the fuel is further atomized and injected into the combustion chamber, thereby improving the combustibility and further improving the fuel consumption. be able to.
[0071]
Also, three intake valves 27, 28 and exhaust valves 29, which are odd in number, are arranged in the cylinder head 14, and the spark plug 26 is arranged in line with the exhaust valve 29 which is the smaller number of valves. Since it is attached to the cylinder head 14, it is possible to increase the degree of freedom in the arrangement of the spark plug 26 by arranging the spark plug 26 by effectively utilizing the empty space generated around the exhaust valve 29, and to ignite the ignition plug 26. Since the plug 26 can be brought closer to the second injection valve 108, the fuel spray from the second injection valve 108 can be collected near the center of the combustion chamber 19, which further reduces fuel consumption due to layered dilution. Can be planned.
[0072]
Moreover, the spark plug 26 corresponds to the first intake port 20 which is one end side in the parallel direction among the first and second intake ports 20, 21 arranged in parallel and is shifted from the center of the combustion chamber 19. Is attached to the cylinder head 14 and flows into the combustion chamber 19 from the first intake port 20 into the ceiling wall 19a of the combustion chamber 19 around the open end of the first intake port 20 to the combustion chamber 19. A guide wall 142 is provided for guiding the intake air to circulate around the spark plug 26.
[0073]
Accordingly, the intake air flowing into the combustion chamber 19 from the first intake port 20 is guided by the guide wall 142 of the ceiling wall 19a of the combustion chamber 19 and flows through the combustion chamber 19 so as to bypass the spark plug 26. Therefore, the intake air is not dispersed in the combustion chamber 19 by colliding with the spark plug 26, and the air-fuel mixture in the combustion chamber 19 is not agitated. Can be further reduced.
[0074]
A cavity 143 is provided in the center of the surface of the piston 17 facing the combustion chamber 19, and a second injection valve 108 that directly injects fuel into the combustion chamber 19, a pair of intake ports 20, 21, The exhaust port 22 corresponding to the two intake ports 21 and the spark plug 26 are disposed in the cylinder head 14 so as to surround the second injection valve 108 with both the intake ports 20, 21, the exhaust port 22 and the spark plug 26. Therefore, by arranging the second injection valve 108 and the spark plug 26 in the center of the combustion chamber 19 and making the cavity 143 of the piston 17 compact, the mixture is stratified and the compression ratio is improved. Combustion efficiency can be improved and fuel consumption can be further reduced.
[0075]
Further, an injector 25 including a second injection valve 108 is disposed on the cylinder axis C, and the first intake port 20 and the exhaust port 22 are provided on both sides of the injector 25 on a projection view on a plane orthogonal to the cylinder axis C. Since the second intake port 22 is disposed on one side of the injector 25 on the other straight line L2 that is substantially orthogonal to the straight line L1 that connects the first intake port 20 and the exhaust port 22, the injector 25 Is disposed in the center of the combustion chamber 19 and the combustion efficiency can be improved by eliminating the bias in the flame propagation distance in the combustion chamber 19. The first and second intake ports 20, 21 can be By providing, it is possible to improve the air filling efficiency and reduce the pumping loss, and in addition to the two intake valves 27, 28 and one exhaust valve 29. Wataru a can be easily avoided to place the spark plug 26, it is possible to improve the combustion efficiency as possible the close proximity to the injector 25 of the spark plug 26.
[0076]
Further, the tip of the nozzle 108a provided in the second injection valve 108 enters the cavity 143 of the piston 17 at the top dead center, so that the combustion efficiency is improved by spraying the air-fuel mixture containing the refined fuel into the cavity 143. The fuel consumption can be further improved and the fuel consumption can be further reduced.
[0077]
Further, a projection 144 projecting toward the piston 17 is provided on the ceiling wall 19a of the combustion chamber 19, and the spark plug 26 has a tip projecting from the projection 144 into the combustion chamber 19 at the tip of the second injection valve 108, that is, a nozzle. Since it is attached to the cylinder head 14 so as to be disposed below the front end of 108a, the front end of the spark plug 26 is disposed below the second injection valve 108 in the cavity 143. The effect of the swirl inside is suppressed, stirring due to the bias of the air-fuel mixture is prevented, and a stratified state with a rich mixing ratio can be formed at the bottom of the cavity 143, improving the ignition performance and further lean combustion The fuel consumption can be reduced. Moreover, since the cavity 143 becomes deeper toward the spark plug 26 side, a rich air-fuel mixture exists on the spark plug 26 side, so that the ignition performance can be further improved.
[0078]
In addition, intake side and exhaust side second rocker arms 44 and 45 that are connected to and connected to the intake valves 27 and 28 and the exhaust valve 29 to be disposed between the intake valves 27 and 28 and the exhaust valve 29 are fixed to the cylinder head 14. A pair of intake side and exhaust side drive rods 46, which are pivotally supported by the intake side and exhaust side second rocker shafts 58, 59, respectively, and are arranged at positions corresponding to one end portions of both rocker shafts 58, 59, 47 is interlocked and connected to the other end portions of the intake side and exhaust side second rocker arms 44 and 45, respectively, so that the intake side and exhaust side of the valve gear 38 for driving the intake valves 27 and 28 and the exhaust valve 29 are connected. Only the second side rocker arms 44, 45 and the second side rocker shafts 58, 59 on the intake side and the exhaust side are arranged on the cylinder head 14 so that the cylinder head 14 is disposed. It is possible to enable 14 miniaturization of.
[0079]
The intake side and exhaust side drive rods 46 and 47 are driven by the rotation of the camshaft 41 arranged in the cylinder block 13 on one axial side of the intake side and exhaust side second rocker shafts 58 and 59. The cylinder head 14 side is arranged with a small distance between the intake side and the exhaust side second rocker shafts 58, 59, and the intake side and exhaust side second rocker arms 44, 45 are connected to each other. Since it is linked and connected to the other end portion, the interval between the intake side and exhaust side second rocker shafts 58 and 59 can be set narrower, and the intake side and exhaust side second rocker shafts 58 and 59 It is possible to reduce the size of the cylinder head 14 in a direction along a straight line connecting the axes.
[0080]
The spark plug 26 is attached to the cylinder head 14 on the side opposite to the intake side and exhaust side drive rods 46 and 47 with respect to the injector 25 including the second injection valve 108. According to the arrangement, the interlocking and connecting portions of the intake side and exhaust side second rocker arms 44, 45 and the intake side and exhaust side drive rods 46, 47 are arranged, so that the ignition plug is avoided by avoiding a portion having little free space. 26, the degree of freedom in the arrangement of the spark plug 26 can be increased, and the spark plug 26 can be brought closer to the second injection valve 108, so that the fuel from the second injection valve 108 can be increased. Combined with the ability to collect the spray in the vicinity of the center of the combustion chamber 19, fuel consumption can be further reduced by layered dilution.
[0081]
Between the cylinder head 14 and the head cover 15 constituting a part of the engine main body 11, a first valve operating chamber 48 for accommodating and arranging a part of the valve operating device 38 is formed. 12, the cylinder block 13 and the cylinder head 14 return the oil lubricated to the oil pan 12a formed in the lower part of the crankcase 12 by lubricating the portion of the valve operating device 38 accommodated in the first valve operating chamber 48. A two-valve chamber 49 is formed on the side of the cylinder bore 16 so as to extend parallel to the cylinder axis C. In addition, oil is introduced into the pump case 63 of the air pump 61 disposed below the second valve chamber 49 for introducing a part of the oil flowing through the second valve chamber 49 into the pump case for lubrication. A hole 85 is provided so as to communicate with the second valve operating chamber 49.
[0082]
Therefore, a part of the oil that returns to the oil pan 12a after lubricating a part of the valve operating device 38 is surely guided to the oil introduction hole 85 of the air pump 61, and the lubrication of the air pump 61 is ensured with a simple structure. Can be fulfilled.
[0083]
In addition, since the pump case 63 is formed integrally with the cylinder block 13 having a smaller outer shape than the cylinder head 14 and the crankcase 12, the entire engine can be reduced in size while reducing the number of parts. The communication between the valve chamber 49 and the oil introduction hole 85 is facilitated, and the oil supply structure to the air pump 61 can be simplified.
[0084]
The second valve chamber 49 houses a first driven sprocket 52, a first drive sprocket 60, and a cam chain 53 for transmitting power from the crankshaft 10 to the camshaft 41 of the valve gear 38. By using the second valve chamber 49 that houses the first driven sprocket 52, the first drive sprocket 60, and the cam chain 53 as an oil return passage, the engine can be downsized and the structure for supplying oil to the air pump 61 can be simplified. Can be achieved.
[0085]
The camshaft 41 is accommodated and arranged in the second valve operating chamber 49, and the camshaft 41 and the camshaft 41 are arranged so that oil splashes separated by the action of centrifugal force as the camshaft 41 rotates are guided to the oil introduction hole 85 side. Since the relative position of the oil introduction hole 85 is set, the camshaft 41 is satisfactorily lubricated with the oil flowing through the second valve valve chamber 49, and oil splashes scattered by the rotation of the camshaft 41 are prevented. The air pump 61 can be effectively guided to improve the lubrication of the air pump 61.
[0086]
A power transmission means 89 for transmitting the power of the camshaft 41 to the pump drive shaft 73 is provided between the pump drive shaft 73 connected to the air pump 61 and the camshaft 41, and the camshaft 41 for driving the air pump 61 is connected to the camshaft 41. Arranged close to the air pump 61, the structure of the power transmission means 89 can be simplified, and the engine can be downsized.
[0087]
Moreover, since the camshaft 41 is also arranged in the cylinder block 13 having a relatively small outer shape, it can further contribute to downsizing of the engine, and power transmission means 89 that transmits the power from the camshaft 41 to the air pump 61. Can be configured in a compact manner, and the degree of freedom in setting the gear ratio of the air pump 61 is increased. In addition, since the power transmission means 89 is configured to transmit power by the endless chain 80, the cylinder block 13 is prevented from being enlarged regardless of the distance between the camshaft 41 and the pump drive shaft 73. In addition, the number of parts can be reduced.
[0088]
In addition, a protruding wall 36 facing the oil flow direction 137 in the second valve operating chamber 49 protrudes from the cylinder block 13 so as to guide the oil in the lower portion in the second valve operating chamber 49 to the oil introduction hole 85. Thus, the oil can be effectively guided to the oil introduction hole 85 by the projecting wall 86, and the lubrication of the air pump 61 can be made better.
[0089]
By the way, the air pump 61 is configured in a reciprocating manner, and a relatively high air pressure can be obtained. Moreover, since the pump drive shaft 73 to which the power from the camshaft 41 for reciprocating the piston 66 in the direction parallel to the cylinder axis C is transmitted is connected to the piston 66 via the Scotch yoke crank 84, the air pump 61 By making the operation axis and the cylinder axis C parallel to each other and adopting the Scotch-yoke crank 84 to eliminate the need for a connecting rod, the engine can be downsized.
[0090]
The air pump 61 is connected to the pump chamber 65 disposed on the cylinder head 14 side so as to generate compressed air corresponding to the volume contraction, and the atmospheric pressure disposed on the oil pan 12a side through the oil pan 12a. A piston 66 that faces both ends of the chamber 88 is slidably fitted to the pump case 63, and is more atmospheric than the piston ring 138 that is attached to the outer periphery of the piston 66 and slidably contacts the inner periphery of the pump case 63. On the 88 side, the oil introduction hole 85 opens to the inner periphery of the pump case 63, so that the oil that has been lubricated in the air pump 61 moves from the atmospheric pressure chamber 88 to the oil pan 12 a side by the pumping action of the piston 66. As a result, the air pump 61 can be discharged efficiently, and the operating efficiency and lubrication of the air pump 61 can be improved.
[0091]
Incidentally, the pump case 63 of the air pump 61 is formed into a bottomed cylindrical shape with the cylinder head 14 side open, and is integrally formed with the cylinder block 13, and a lid that hermetically closes the cylinder head 14 side opening of the pump case 63. Since the member 64 is coupled to the pump case 63 in the same plane as the coupling surface 87 of the cylinder block 13 and the cylinder head 14, the number of processing steps of the cylinder block 13 can be reduced.
[0092]
Further, since the air pump 61 and the water pump 90 connected to both ends of the pump drive shaft 73 are disposed at positions that are plane-symmetrical with respect to the plane PL orthogonal to the pump drive shaft 73 including the cylinder axis C, the air pump The water pump 90 is driven by the pump drive shaft 73 connected to 61, so that the number of parts and the weight can be reduced, and the cost can be reduced by the simplification of processing and assembly. Further, the protrusion of the water pump 90 from the cylinder block can be suppressed, and the overall size of the cylinder block 13 can be avoided.
[0093]
Moreover, the water pump 90 can be disposed in the vicinity of the cylinder block 13 and the cylinder head 14 to be water-cooled, the water piping can be shortened, the complication of the piping can be avoided, and the pressure loss in the piping can be kept small. be able to.
[0094]
Further, since the injector 25 for directly injecting fuel into the combustion chamber 19 together with the compressed air obtained by the air pump 61 is disposed in the cylinder head 14, the air pump 61 is not disposed in the cylinder head 14, so that the layout is free. The injector 25 and its piping can be disposed on the Linder head 14 while increasing the degree and reducing the size of the engine. In particular, since the pump chamber 65 of the air pump 61 is disposed on the cylinder head 14 side, the compressed air supply path 126 that guides the compressed air from the air pump 61 to the injector 25 by relatively shortening the distance between the pump chamber 65 and the injector 25. Therefore, it is possible to avoid complication of the pipe structure including the pressure loss and to reduce the pressure loss in the pipe structure.
[0095]
A portion of the compressed air supply path 126 passes through the vicinity of the exhaust port 24, whereby the compressed air flowing through the compressed air supply path 126 can be warmed by the exhaust heat of the exhaust gas flowing through the exhaust port 24. Thus, the pump efficiency can be improved by increasing the volume of the compressed air.
[0096]
Moreover, in the vicinity of the exhaust port 24, a part of the head-side water jacket 103 is disposed between the exhaust port 24 and the cylinder block 13, whereas a passage 128 constituting a part of the compressed air supply path 126. Is disposed on the opposite side of the head-side water jacket 103 with respect to the exhaust port 24, so that the influence of cooling by the head-side water jacket 103 can be prevented from reaching the compressed air flowing through the compressed air supply path 126 as much as possible. Even a water-cooled engine can maintain high pump efficiency.
[0097]
The air pump 61 is disposed below the cylinder block 13 on the side corresponding to the exhaust port 24, and the air pump 61 is disposed in an engine disposition space including an exhaust pipe connected to the exhaust port 24. It becomes possible to do.
[0098]
The injector 25 is a first injection valve 107 that is attached to the head cover 15 so as to inject fuel, and a second injection that is attached to the cylinder head 14 so that fuel is directly injected into the combustion chamber 19 together with compressed air. The valve 108 is coaxially connected, and when performing fuel injection by air assist, the first and second injection valves 107 and 108 may be sequentially attached to the head cover 15 and the cylinder head 14. The attaching operation is not complicated, and the number of parts can be reduced. In addition, since it is only necessary to secure a space for attaching the second injection valve 108 to the cylinder head 14, the cylinder head 14 secures the valve body to which the both injection valves are attached to the cylinder head. The installation space to be reduced can be reduced, and the cylinder head 14 can be reduced in size.
[0099]
The first injection valve 107 of the injector 25 is fitted and held in the injector housing 114. The injector housing 114 is formed integrally with the head cover 15, so that the injector housing 114 is provided around the cylinder head 14. Therefore, the number of parts can be reduced, and the enlargement of the engine and the complexity of the structure around the engine can be avoided.
[0100]
In addition, since the second injection valve 108 is inserted into the cylinder head 14 and is sandwiched between the tip of the injector housing 114 and the cylinder head 14, the second injection valve 108 is inserted into the cylinder head 14 from the head cover 15 side. The second injection valve 108 can be positioned with respect to the cylinder head 14 simply by coupling the head cover 15 to the cylinder head 14, and the assembly work of the second injection valve 108 to the cylinder head 14 becomes easy. Assembling workability can be improved.
[0101]
By the way, the first injection valve 107 is attached to the head cover 15 with the wiring connector 107a facing the outside of the head cover 15, and a conducting wire 112 connected to the second injection valve 108 is sandwiched between the cylinder head 14 and the head cover 15. Since the second injection valve 108 is attached to the cylinder head 14 and the conducting wires 112 extending from the second injection valve 108 are inserted into the grommet 113, the head cover is attached to the cylinder head 14. 15 and further attaching the first injection valve 107 to the head cover 15, the assembly including wiring to both injection valves 107 and 108 can be completed, and the assembly can be further improved. it can.
[0102]
Further, an air chamber 122 for storing compressed air introduced into the second injection valve 108 is formed between the first and second injection valves 107 and 108 in the injector housing 114, and the compressed air is supplied to the second injection valve 108. A part of the compressed air supply structure for guiding to the injection valve 108 can be shared by the injector housing 114.
[0103]
Further, a fuel supply passage 119 for supplying fuel and compressed air to the injector housing 114 and a passage 129 which is a part of the compressed air supply passage 126 are directly provided in the head cover 15. There is no need to arrange pipes and the like for supplying fuel and compressed air around the injector housing 114, which can reduce the number of parts and increase the size of the engine and the structure of the engine periphery. Can be avoided.
[0104]
Moreover, the passage 128 which is a part of the compressed air supply passage 126 is provided in the cylinder head 14 on the other end side of the intake side and exhaust side second rocker shafts 58 and 59, and is compressed by avoiding the valve operating device 38. By providing a part of the air supply path 126 in the cylinder head 14, an increase in the size of the cylinder head 14 can be avoided.
[0105]
By the way, the camshaft 41 that constitutes a part of the valve gear 38 that drives the first intake valve 27, the second intake valve 28, and the exhaust valve 29 disposed in the cylinder head 14 includes the cylinder head 14 and the head cover. It is arranged in the cylinder block 13 while avoiding 15 spaces. For this reason, the camshaft 41 is not disposed between the cylinder head 14 and the head cover 15 to increase the degree of freedom in the layout of the injector housing 114, and the fuel supply passage 119 and the passage directly provided in the head cover 15 are provided. The degree of freedom of the layout of 129 can be increased.
[0106]
The second injection valve 108 of the injector 25 is supported by the head cover 15, and a passage 129 that is a part of the compressed air supply path 126 that supplies compressed air to the second injection valve 108 is directly provided in the head cover 15. Thus, parts for guiding the compressed air to the injector 25 are not arranged around the head cover 15, and it is possible to avoid an increase in the size of the engine and a complicated structure around the engine.
[0107]
Further, both end portions of a cylindrical knock pin 130 straddling the mating surfaces of the cylinder head 14 and the head cover 15 are inserted into the cylinder head 14 and the head cover 15, constituting a part of the compressed air passage 126, and The direct passages 128 and 129 communicate with each other via the knock pin 130 so that the relative positions of the cylinder head 14 and the head cover 15 are determined by the knock pin 130, and the injector 25 cooperates with the head cover 15 and the cylinder head 14. Even if supported, the injector 25 is not subjected to excessive stress. Further, the knock pin 130 is used as a connecting member for the passage 128 of the cylinder head 14 and the passage 129 of the head cover 15, so that a dedicated part for connecting the passage is unnecessary, which contributes to a reduction in the number of parts.
[0108]
Further, since the orifice 131 is formed in the knock pin 130, the pressure of the compressed air supplied to the injector 25 can be adjusted, and a dedicated part is not necessary for the pressure adjustment, which can contribute to a reduction in the number of parts.
[0109]
Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various design changes can be made without departing from the present invention described in the claims. It is.
[0110]
【The invention's effect】
As described above, according to the first aspect of the present invention, the fuel injected from the injection valve can be collected in the vicinity of the center of the combustion chamber, lean combustion can be performed, fuel consumption can be reduced, and the intake valve and Of the valve gears for driving the exhaust valve, it is possible to reduce the size of the cylinder head by disposing only the rocker arm and the rocker shaft that pivots the rocker arm.
[0111]
  A pair of drive rods that operate in the axial direction following the rotation of the camshaft to which rotational power is transmitted from the crankshaft and that are linked to and connected to both rocker arms are located at positions corresponding to one end portions of both rocker shafts. Since the distance between the rocker shafts is gradually narrowed as it approaches the rocker arm, the distance between the rocker shafts can be set narrower, and the cylinder head can be downsized along the straight line connecting the axes of the rocker shafts. Can be achieved. And the pair of drive rodsBoth are, And is inclined toward the cylinder axis toward the rocker arm.
[0112]
  Claim2According to the described invention, the degree of freedom in the arrangement of the spark plug can be increased, and the spark plug can be brought closer to the fuel injection valve, so that the fuel spray from the injection valve is collected near the center of the combustion chamber. In combination with this, the fuel consumption can be further reduced by layered dilution.
[0113]
  Claim3According to the described invention, it is possible to increase the degree of freedom in the arrangement of the spark plugs by arranging the spark plugs by effectively utilizing the empty space generated around the valve on the side where the number of arrangements is small. Since the spark plug can be brought closer to the fuel injection valve, fuel consumption from the injection valve can be collected near the center of the combustion chamber, and in addition, fuel consumption can be further reduced by layered dilution.
[0114]
  Further claims4According to the described invention, fuel can be further atomized and injected into the combustion chamber to improve combustibility and further improve fuel efficiency, and a part of the compressed air supply path is connected to the other end of the rocker shaft. By providing in the cylinder head, a passage can be formed in the cylinder head while preventing an increase in the size of the cylinder head, thereby preventing an increase in the number of parts.
[Brief description of the drawings]
FIG. 1 is a partially longitudinal side view of an engine.
FIG. 2 is a view taken along line 2-2 of FIG. 1 with the head cover removed.
3 is a cross-sectional view taken along line 3-3 of FIG.
4 is a cross-sectional view taken along line 4-4 of FIG.
5 is a cross-sectional view taken along line 5-5 of FIG.
6 is an enlarged cross-sectional view of the cylinder head taken along line 6-6 in FIG.
7 is a cross-sectional view taken along line 7-7 in FIG.
8 is a cross-sectional view taken along line 8-8 in FIG.
9 is a cross-sectional view taken along line 9-9 of FIG.
10 is a longitudinal side view of the engine taken along the line 10-10 in FIG. 2; FIG.
[Explanation of symbols]
14 ... Cylinder head
19 ... Combustion chamber
26 ... Spark plug
27, 28 ... Intake valve
29 ... Exhaust valve
41 ... Camshaft
44, 45 ... Rocker arm
46, 47 ... Driving rod
58, 59 ... Rocker shaft
108 ... Injection valve
126 ... Compressed air supply path
C ... Cylinder axis

Claims (4)

In a four-cycle direct injection engine that directly injects fuel into the combustion chamber (19),
The intake valve (27, 28) and the exhaust valve (29) are arranged such that the operation axes of the valves (27, 28; 29) are V-shaped on the projection onto the virtual plane including the cylinder axis (C). closing operably disposed in the cylinder head (14), the cylinder axis (C) and the injection valve which is arranged coaxially (108), the intake so as to inject fuel directly into the combustion chamber (19) attached to the cylinder head (14) between the valve (27, 28) and an exhaust valve (29), the intake valve (27, 28) and an exhaust valve (29) at one end is interlocked respectively, coupled to the intake valve ( 27, 28) and an exhaust valve (29) the intake side and exhaust side rocker arms (44, 45) is disposed between the intake-side fixed the virtual plane as the cylinder head has an axis perpendicular (14) and the exhaust-side Rokkashafu (58, 59) in the swing pivotally supported respectively, of the intake-side and exhaust-side rocker shaft (58, 59), said at one axial side away from the injection valve (108) is disposed in the cylinder block (13) A pair of drive rods (46, 47) operating in the axial direction following the rotation of the camshaft (41) to which rotational power is transmitted from the crankshaft (10) are provided on the intake side and exhaust side rocker arms (44, 45). ), The exhaust-side rocker arm (45) is connected to the drive rod (46) more than the axis of the injection valve (108) in the direction along the axis of the rocker shaft (58, 59). , 47) are arranged offset to the side, the pair of driving rods (46, 47) is to respond to the one end portion of the axial one side of the both rocker shafts (58, 59) While being arranged gradually narrowing the spacing toward the both rocker arms (44, 45) at a position, wherein the cylinder axis both said toward the rocker arms (44, 45) of the two drive rods (46, 47) (C) A four-cycle direct injection engine characterized by being inclined toward the side . Characterized in that said ignition plug (26) is attached to the cylinder head on the opposite side (14) of the the two drive rods (46, 47) with respect to injection valve (108), four-cycle straight of claim 1, wherein Jet engine.   As a whole, an odd number of the intake valves (27, 28) and the exhaust valves (29) are arranged in the cylinder head, and the intake valve (27, 28) or the exhaust valve (29) has the smaller number. The four-stroke direct injection engine according to claim 1, characterized in that the spark plugs (26) are attached to the cylinder head (14) in a line.   The injection valve (108) is configured to inject fuel together with compressed air directly into the combustion chamber (19), and a part of the compressed air supply path (126) for guiding the compressed air to the injection valve (108) The four-cycle direct injection engine according to claim 1, wherein the cylinder head (14) is provided at the other end of the rocker shaft (58, 59).

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