JP2004116447A - Four cycle direct-injection engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve imposing workability when imposing an injection valve for directly injecting fuel into a combustion chamber on a cylinder head in a four cycle direct-injection engine for directly injecting a fuel into the combustion engine. <P>SOLUTION: The injection valve 108 for directly injecting the fuel into the combustion chamber 19 is inserted into the cylinder head 14 from a head cover 15 side. A positioning part 114 for positioning the injection valve 108 with respect to the cylinder head 14 is installed in the head cover 15. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD 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, in such a four-cycle direct injection engine, for example, an injection valve as disclosed in Patent Document 1 is used.
[0003]
[Patent Document 1]
Japanese Patent No. 2765761
[Problems to be solved by the invention]
However, in the above conventional device, the injection valve for injecting the fuel is mounted on the valve body in parallel with the air assist injection valve. The mounting of the injection valve and the mounting of the valve body to the cylinder head are required, and the assembling work becomes complicated.
[0005]
The present invention has been made in view of such circumstances, and it is an object of the present invention to provide a four-cycle direct injection engine with improved workability when assembling an injection valve for directly injecting fuel into a combustion chamber to a cylinder head. This is the first purpose.
[0006]
In addition, in order to perform air-assisted fuel injection, in the above-described related art, it is necessary to attach a valve body, which is relatively large due to the arrangement of both injection valves in parallel, to the cylinder head, which makes assembly work complicated. In addition, the number of parts becomes relatively large, and a relatively large mounting space needs to be secured in the cylinder head, which leads to an increase in the size of the engine.
[0007]
The present invention has been made in view of the above circumstances, and in performing fuel injection by air assist, a four-cycle direct injection engine capable of improving assembly workability, reducing the number of parts, and reducing the size of a cylinder head. The second object is to provide
[0008]
[Means for Solving the Problems]
In order to achieve the first object, according to the first aspect of the present invention, in a four-cycle direct injection engine for directly injecting fuel into a combustion chamber, an injection valve for directly injecting fuel into the combustion chamber has a cylinder head from a head cover side. And a positioning portion for positioning the injection valve with respect to the cylinder head is provided on the head cover, and is characterized by four cycles.
[0009]
According to the configuration of the invention described in claim 1, the injection valve for directly injecting the fuel into the combustion chamber is inserted into the cylinder head from the head cover side, and the head cover is connected to the cylinder head. The injection valve can be positioned, and the work of assembling the injection valve to the cylinder head is facilitated, and the workability of the assembly can be improved.
[0010]
According to another aspect of the present invention, in a four-cycle direct injection engine for directly injecting fuel into a combustion chamber, a first injection valve for injecting fuel is attached to a head cover. A second injection valve coaxially connected to the first injection valve is attached to the cylinder head so that fuel is directly injected into the combustion chamber together with the compressed air.
[0011]
According to the configuration of the invention described in claim 2, when performing the fuel injection by the air assist, the first and second injection valves may be sequentially mounted on the head cover and the cylinder head, so that the assembling work is complicated. And the number of parts can be reduced. In addition, since it is sufficient to secure a space for mounting the second injection valve in the cylinder head, the valve body having both injection valves mounted is secured by the cylinder head as compared with the conventional one in which the valve body is mounted on the cylinder head. The required mounting space can be reduced, which can contribute to the downsizing of the cylinder head.
[0012]
According to a third aspect of the invention, in addition to the configuration of the second aspect, the first injection valve is fitted and held in a cylindrical injector housing provided on a head cover, and the second injection valve is provided. A valve is inserted into the cylinder head and is sandwiched between the tip of the injector housing and the cylinder head. According to such a configuration, it is easy to attach the second injection valve to the cylinder head. The attachment property can be further improved.
[0013]
According to a fourth aspect of the present invention, in addition to the configuration of the second or third aspect, the wiring connector of the first injection valve faces the outside of the head cover, and the first injection valve is attached to the head cover. The lead connected to the second injection valve is drawn out through a grommet sandwiched between the cylinder head and the head cover, and according to this configuration, the second injection valve is attached to the cylinder head. At the same time, the head cover is connected to the cylinder head with the lead extending from the second injection valve being inserted into the grommet, and the first injection valve is attached to the head cover, thereby completing the assembly including the wiring to both injection valves. Therefore, the assemblability can be further improved.
[0014]
According to a fifth aspect of the present invention, in addition to the configuration of the second or third aspect of the invention, a second injection valve is introduced between the first and second injection valves in the injector housing. An air chamber for storing compressed air is formed. According to such a configuration, a part of the compressed air supply structure for guiding the compressed air to the second injection valve can be shared by the injector housing. .
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described based on an embodiment of the present invention shown in the attached drawings.
[0016]
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 of FIG. 1 with a head cover removed, 3 is a sectional view taken along line 3-3 of FIG. 2, FIG. 4 is a sectional view taken along line 4-4 of FIG. 3, FIG. 5 is a sectional view taken along line 5-5 of FIG. 7 is a sectional view taken along line 7-7 of FIG. 2, FIG. 8 is a sectional view taken along line 8-8 of FIG. 7, FIG. 9 is a sectional view taken along line 9-9 of FIG. 7, and FIG. FIG. 10 is a longitudinal sectional side view of the engine taken along line 10-10 of FIG. 2.
[0017]
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. It has a cylinder head 14 connected to the cylinder block 13 on the opposite side, and a head cover 15 connected to the cylinder head 14 on the opposite side to the cylinder block 13. It is mounted on vehicles such as motorcycles.
[0018]
Referring to FIGS. 2 to 4 together, a piston 17 slidably fitted to a cylinder bore 16 provided in a cylinder block 13 is a crankshaft 10 (FIG. 1) rotatably supported by a crankcase 12. ) Via a connecting rod 18 and a crank pin (not shown). A combustion chamber 19 facing the top of the piston 17 is formed between the cylinder block 13 and the cylinder head 14.
[0019]
The cylinder head 14 has first and second intake ports 20, 21 which are individually opened at the ceiling wall 19 a of the combustion chamber 19 and open at the upper side surface of the cylinder head 14 with the other end commonly connected. Are provided in parallel with each other, and an exhaust port 22 having one end opened to the ceiling wall 19 a of the combustion chamber 19 and the other end opened to the lower side surface of the cylinder head 14.
[0020]
Open ends of the first and second intake ports 20, 21 to the combustion chamber 19 are opened and closed by first and second intake valves 27, 28, respectively, and 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 and 28 and an exhaust valve 29 as a whole so as to be capable of opening and closing, and the first and second intake valves 27 and 28 are fixed to the cylinder head 14. , Each of which is slidably fitted to a corresponding one of the guide cylinders 30 and which is fixed to the upper end of each of the intake valves 27 and 28 protruding from the guide cylinder 30, and a valve spring 32 between the cylinder head 14. Are provided, and both intake valves 27 and 28 are urged 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 provided between the cylinder head 14 and a retainer 34 fixed to an upper end of the exhaust valve 29 protruding from the guide cylinder 33. The exhaust valve 29 is urged in the valve closing direction by the spring force exerted by the valve spring 35.
[0021]
Moreover, the operating axes of the two intake valves 27 and 28, that is, the axes of the two guide cylinders 30 are arranged in parallel so as to be orthogonal to the axis of the crankshaft 10 and overlap each other on a projection plane including the cylinder axis C on a virtual plane. The operating axes of the intake valves 27 and 28 and the operating axis of the exhaust valve 29, that is, the axis of the guide cylinder 33 are V-shaped in the projection view onto the virtual plane, so that the two intake valves 27 and 28 and An exhaust valve 29 is disposed on the cylinder head 14 so as to be capable of opening and closing.
[0022]
By the way, on a projection view onto a plane orthogonal to the cylinder axis C, a first intake port 20 and an 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 provided. The second intake port 21 is arranged on one side of the cylinder axis C on another straight line L2 substantially orthogonal to the first intake port 20 so as to be aligned with the first intake port 20. In addition, it corresponds to the first intake port 20 on one end side in the parallel direction of the two intake ports 20 and 21 and is located at a position 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.
[0023]
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 in the cylinder head 14 between the exhaust valves 27, 28 and the exhaust valve 29. In this embodiment, the injector 25 is arranged on the cylinder head 14 coaxially with the cylinder axis C.
[0024]
That is, the injector 25, the pair of intake ports 20, 21, the exhaust port 22 corresponding to the second intake port 21, and the ignition plug 26 are used to connect the injector 25 to both the intake ports 20, 21, the exhaust port 22, and the ignition plug. It is disposed on the cylinder head 14 so as to be surrounded by 26.
[0025]
In FIG. 5, the ceiling of the combustion chamber 19 around the opening end to the combustion chamber 19 of the first intake port 20 arranged at one end in the parallel direction among the first and second intake ports 20 and 21 arranged side by side. A guide wall 142 that guides the intake air flowing from the first intake port 20 into the combustion chamber 19 to bypass the ignition plug 26 located at a position corresponding to the first intake port 20 is provided on the wall 19a. Provided.
[0026]
Referring also to FIG. 6, a cavity 143 is provided at the center of the surface of piston 17 facing combustion chamber 19. A projection 144 projecting toward the piston 17 is formed on the ceiling wall 19 a of the combustion chamber 19, and the spark plug 26 has a tip projecting from the projection 144 into the combustion chamber 19 positioned below the tip of the injector 25. To the cylinder head 14. Moreover, the cavity 143 is formed so as to become deeper toward the ignition plug 26 side.
[0027]
With further reference to FIGS. 7 to 9, the first and second intake valves 27 and 28 and the exhaust valve 29 are driven to open and close by a valve operating device 38. A camshaft 41 that rotates having intake-side and exhaust-side cams 39, 40, an intake-side first rocker arm 42 that swings by following the intake-side cam 39, and swings by following 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 arms 44a and 44b on one end side that contact the first and second intake valves 27 and 28, and the exhaust valve 29. The second rocker arm 45 on the exhaust side, which has a pressing arm portion 45a on one end side, and the first and second rocker arms 4 on the intake side so as to transmit the swinging motion of the first rocker arm 42 on the intake side to the second rocker arm 44 on the intake side. , 44, and between the exhaust-side first and second rocker arms 43, 45 so as to transmit the swinging motion of the exhaust-side first rocker arm 43 to the exhaust-side second rocker arm 45. And an exhaust-side drive rod 47 to be provided.
[0028]
Between the cylinder head 14 and the head cover 15, the intake side and exhaust side second rocker arms 44, 45 of the valve train 38, and the intake side and exhaust side that swing and pivot the intake side and exhaust side second rocker arms 44, 45. A first valve operating chamber 48 for housing and disposing upper portions of the second side rocker shafts 58 and 59 and the upper portions of the intake side and exhaust side drive rods 46 and 47 is formed, and the crankcase 12, the cylinder block 13 and the cylinder head 14 are formed. A second valve operating chamber 49 for accommodating the remaining portion of the valve operating device 38 is formed so as to extend parallel to the cylinder axis C on the side opposite to the side where the ignition plug 26 is disposed with respect to the cylinder axis C. Is done.
[0029]
In order to lubricate a portion of the valve operating device 38 housed in the first valve operating chamber 48, an oil ejection hole 36 is provided in the head cover 15, and a portion accommodated in the first valve operating chamber 48 is provided. Is returned to the oil pan 12a (see FIG. 1) formed in the lower part of the crankcase 12 via the second valve chamber 49.
[0030]
The intake-side and exhaust-side first rocker arms 42, 43 have rollers 54, 55 that come into rolling contact with the intake-side and exhaust-side cams 39, 40 from the cylinder head 14 side, respectively, and have axes parallel to the camshaft 41. And is swingably supported by intake side and exhaust side first rocker shafts 56 and 57 provided between the cylinder block 13 and the cover 50. On the intake side and exhaust side first rocker arms 42, 43, bowl-shaped pressing portions 42a, 43a located on the opposite side to the rollers 54, 55 are provided integrally with each other so as to open to the cylinder head 14 side. .
[0031]
The camshaft 41 of the valve train 38 is disposed in the cylinder block 13 so as to be accommodated in the second valve train 49. Both ends of a camshaft 41 having an axis parallel to the crankshaft 10 are rotatably supported by a cover 50 fastened to the cylinder block 13 via ball bearings 51, 51.
[0032]
In addition, the camshaft 41 has an oil supply passage 37 for supplying lubricating oil to sliding portions between the intake-side and exhaust-side cams 39 and 40 and the intake-side first rocker arm 42 and the exhaust-side first rocker arm 43. Is provided.
[0033]
The first driven sprocket 52, the first driving sprocket 60 (see FIG. 1), and the endless cam chain are used to transmit the power from the crankshaft 10 to the second valve chamber 49 at a reduced speed of １ ／. 53, the first driven sprocket 52 is non-rotatably connected to the camshaft 41, the first driving sprocket 60 is non-rotatably connected to the crankshaft 10, and the cam chain 53 is connected to the first driving sprocket 60. And is wound around the first driven sprocket 52.
[0034]
The intake-side and exhaust-side drive rods 46, 47 extend from the first valve-operating chamber 48 to a part of the second valve-operating chamber 49, and are arranged so that the mutual interval on the cylinder head 14 side is reduced. You. The spherical ends at one end of the intake-side and exhaust-side drive rods 46, 47 are fitted to the pressing portions 42a, 43a of the first intake-side and exhaust-side rocker arms 42, 43 so as to be swingable, and are driven at the intake side and the exhaust side. The spherical ends on the other ends of the rods 46 and 47 are fitted to the pressure receiving parts 44c and 45b of the second and fourth rocker arms 44 and 45 on the intake side and the exhaust side, respectively, so as to swing.
[0035]
In the first valve chamber 48, the cylinder head 14 is supported by the 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. A pair of pressing arms 42a that are fixed and contact with the upper ends of the first and second intake valves 28 and 29 so as to be interlocked with and linked to the two intake valves 28 and 29 so as to be branched in a forked shape. , 42b at one end thereof is rotatably supported by an intake-side second rocker shaft 58, and is brought into contact with the upper end of the exhaust valve 29 so as to interlock and be connected to the exhaust valve 29. An exhaust-side second rocker arm 43 having an arm portion 45 a at one end is swingably supported by an exhaust-side second rocker shaft 59.
[0036]
Further, a bowl-shaped pressure receiving portion 44c which is open to the cylinder block 13 side is provided integrally with 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 arm 45 is provided integrally with a bowl-shaped pressure-receiving portion 45b opened toward the cylinder block 13 on the side opposite to the pressing arm 45a with respect to the exhaust-side second rocker shaft 59.
[0037]
The other ends of the intake-side and exhaust-side second rocker arms 44, 45, that is, the pressure receiving portions 44c, 45b, are disposed between the intake-side and exhaust-side second rocker shafts 58, 59, respectively. The drive rods 46, 47 are interlocked and connected to the other ends of the intake-side and exhaust-side second rocker arms 44, 45 between one ends of the intake-side and exhaust-side second rocker shafts 58, 59.
[0038]
In such a valve operating device 38, the intake-side first rocker arm 42 swings by the intake-side cam 39 in accordance with the rotation of the camshaft 41 to which the 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, and the intake side second rocker arm 44 swings accordingly, whereby the first and second intake valves 27 and 28 are opened and closed, and the exhaust side cam 40 As a result, the exhaust-side first rocker arm 43 swings, whereby the exhaust-side drive rod 47 operates in the axial direction thereof, and the exhaust-side second rocker arm 45 swings accordingly, whereby the exhaust valve 29 is opened and closed. become.
[0039]
The injector 25 is supplied with compressed air from a reciprocating air pump 61 that reciprocates a piston 66 in a direction parallel to the cylinder axis C. The air pump 61 is provided on the cylinder head 14. The exhaust port 24 is disposed below the cylinder block 13 on the side corresponding to the exhaust port 24. Moreover, the cylinder block 13 has an operating chamber 62 disposed below the cylinder bore 16 so as to be substantially L-shaped and continuous with the second valve operating chamber 49 in a plane orthogonal to the cylinder axis C. The air pump 61 is disposed below the second valve chamber 49 in a continuous portion between the second valve chamber 49 and the working chamber 62.
[0040]
Referring also to FIG. 10, the pump case 63 of the air pump 61 has an axis parallel to the cylinder axis C and is formed in a cylinder with a bottom with the cylinder head 14 side open, and is formed integrally with the cylinder block 13. A cover member 64 for closing the opening of the pump case 63 on the cylinder head 14 side in an airtight manner 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.
[0041]
The piston 66 is slidably fitted to the pump case 63, and is disposed between the one end of the piston 66 and the cover member 64 on the cylinder head 14 side so as to generate compressed air in accordance with volume contraction. A pump chamber 65 is formed, and an atmospheric pressure chamber 88 arranged on the oil pan 12a side is formed between the other end of the piston 66 and the closed end of the pump case 63.
[0042]
On the other hand, in the working chamber 62, 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. A plurality of, for example, four fastening bosses 70... Moreover, a cover 72 forming the outer side surface of the working chamber 62 is fastened to the cylinder block 13, and when the cover 72 is opened, the bolts 71 can be tightened and loosened.
[0043]
A pump drive shaft 73 is coaxially inserted into 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. 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.
[0044]
The power from the camshaft 41 is transmitted to the pump drive shaft 73 via a power transmission means 89 at a portion protruding from one end of the bearing member 69. The power transmission means 89 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 loop wound around the second driven and driven sprockets 78, 79. And a chain 80.
[0045]
The pump drive shaft 73 is connected to a piston 66 of the air pump 61 via a scotch / yoke type crank 84, and the scotch / yoke type crank 84 is slidably fitted to the piston 66. And a tip of an eccentric shaft 73a projecting from an eccentric position of one end of the pump drive shaft 73. The eccentric shaft 73a rotates around the axis of the pump drive shaft 73 in response to the rotation of the pump drive shaft 73 by the power transmitted from the camshaft 41, and the piston 66 of the air pump 61 has the capacity of the pump chamber 65. Is reciprocally driven in the axial direction in the pump case 63 so as to increase or decrease.
[0046]
The piston 66 is provided with a sliding hole 67 having an axis arranged on a plane along one diameter line and orthogonal to the axis of the camshaft 41, and the sliding piece 68 is slidable in the sliding hole 67. Is fitted to. Further, the eccentric shaft 73a is integrally provided at one end of the pump drive shaft 73 so as to protrude.
[0047]
The pump case 63 is provided with an opening 76 into which one end of the pump drive shaft 73 is inserted, and the piston 66 has an eccentric shaft 73 a formed on the axis of the sliding hole 67 in accordance with the rotation of the pump drive shaft 73. An insertion hole 77 into which the eccentric shaft 73a is inserted so as to allow the eccentric shaft 73a to move in a direction along the length of the sliding hole 67 is provided so as to communicate with the center of the sliding hole 67 in the longitudinal direction.
[0048]
Through holes 81 and 82 are provided at 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 one of the through holes 81. An oil guide 83 for guiding a part of the oil falling into the space 62 between the bearing member 69 and the pump drive shaft 73 is provided integrally. 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 a lower portion in the first valve operating chamber 48, and is opened to the working chamber 62 through the passage 134. A passage 135 is provided in the cylinder block 13, and an oil guide 83 is provided integrally with the bearing member 69 so as to guide oil falling from the passage 135 to the through hole 81. Further, 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 a lower part in the working chamber 62. The oil accumulated in the lower part of the working chamber 62 is returned to the oil pan 12a from a return passage 136 provided in the cylinder block 13 so as to communicate with the lower part of the working chamber 62.
[0049]
A water pump 90 having a rotation axis coaxial with a pump drive shaft 73 is attached to the cylinder block 13 on the opposite side of the air pump 61 with respect to the bearing member 69. The air pump 61 and the water pump 90 are arranged at positions that are plane-symmetric with respect to the orthogonal plane PL.
[0050]
A pump housing 91 of the water pump 90 has a housing main body 92 formed by integrally connecting a dish-shaped portion 92b to an open end of a bottomed cylindrical portion 92a having a closed pump drive shaft 73 side, and an open end of the housing main body 92. The pump cover 93 is fastened to the cylinder block 13 such that the outer periphery of the open end of the housing main body 92 is sandwiched between the pump cover 93 and the cylinder block 13.
[0051]
At the center of the closed end of the bottomed cylindrical portion 92a and the center of the pump cover 93, both ends of a pump shaft 94 which is coaxial with the pump drive shaft 73 are rotatably supported, 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 coaxially surrounding a bottomed cylindrical portion 92a of the housing main body 92 is fixed to the other end of the pump drive shaft 73 protruding from the other end of the bearing member 69. An outer magnet 98 is fixed to the inner surface of the cylindrical portion 97a. Accordingly, the rotor 95 rotates with the pump shaft 94 in response to the rotation of the rotating member 97 with the pump drive shaft 73.
[0052]
Incidentally, a vortex chamber 99 is formed between the housing main body 92 and the pump cover 93, and the impeller 100 housed in the vortex chamber 99 is provided on the rotor 95.
[0053]
The pump cover 93 is provided with a plurality of suction ports 101 opening at 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. The cooling water discharged from the water pump 90 is supplied to the block-side water jacket 102 provided on the cylinder block 13 and the head-side water jacket 103 provided on the cylinder head 14 through the block-side water jacket 102. Depending on the temperature of the cooling water, a state in which the cooling water discharged from the head-side water jacket 103 is guided to a radiator or the like (not shown) and a state in which the cooling water is returned to the suction ports 101 by bypassing the radiator or the like are provided. Switching is performed 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.
[0054]
In the upper side wall of the pump case 63 of the air pump 61, an oil introduction hole 85 for guiding a part of the oil flowing through the second valve chamber 49 into the pump case 63 for lubrication is provided in the second valve chamber 49. It is provided so as to communicate. By the way, the rotation in the second valve chamber 49 causes the intake cam 39 and the exhaust cam 40 of the camshaft 41 to lift up a part of the oil flowing in the second valve chamber 49 and to act by 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 relative position of the introduction hole 85 is set.
[0055]
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. Is formed in the cylinder block 13 so as to face the oil flow direction 137 in the second valve chamber 49 in a substantially semicircular shape. The oil return hole 85 of 61 is arranged at a position immediately upstream of the protruding wall 86 along the oil flow direction 137. That is, the protruding wall 86 functions to guide the oil flowing in the second valve chamber 49 to the oil introduction hole 85.
[0056]
Moreover, the oil return hole 85 is opened on the inner periphery of the pump case 63 on the atmospheric pressure chamber 88 side of the piston ring 138 mounted on the outer periphery of the piston 66 and slidably in contact with the inner periphery of the pump case 63. The oil return hole 85 always communicates with one end of a slide hole 67 provided in the piston 66 regardless of the axial movement of the piston 66. A pair of grooves 139... Connecting the end of the piston 66 on the atmospheric pressure chamber 88 side and both ends of the sliding hole 67 are provided on the outer periphery of the piston 66, and are introduced into the pump case 63 from the oil return hole 85. Part of the oil is used for lubrication between the piston 66 and the pump case 63, and the remainder flows toward the atmospheric pressure chamber 88 through the grooves 139. Moreover, the grooves 139 also serve to prevent the oil in the sliding hole 67 from leaking out, thereby preventing the pumping action of the sliding piece 68 in the Scotch and yoke type crank 84 from occurring.
[0057]
Thus, the oil flowing into the atmospheric pressure chamber 88 flows from the opening 76 to the working chamber 62 side, and further flows from the return passage 136 to the oil pan 12a side.
[0058]
With particular attention to FIG. 9, the injector 25 includes a first injection valve 107 attached to the head cover 15 for injecting fuel, and a cylinder head 14 for injecting fuel directly into the combustion chamber 19 together with compressed air. And a second injection valve 108 is coaxially connected to the second injection valve 108. The second injection valve 108 has a nozzle 108a that protrudes into the combustion chamber 19.
[0059]
The cylinder head 14 includes a fitting hole 109 for airtightly fitting the nozzle 108a, 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 coaxially with the cylinder axis C, and the second injection valve 108 has 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. The head cover 15 is inserted into the insertion tube 110 until it comes into contact with the step portion 111 via the wave spring washer 123.
[0060]
The tip of the second reflection valve 108, that is, the nozzle 108a, is inserted into the cavity 143 of the piston 17 at the top dead center while being inserted into the insertion tube 110 until it comes into contact with the step portion 111. The tip of the spark plug 26 is located below the nozzle 108a in the cavity 143 when the piston 17 is at the top dead center.
[0061]
A conductor connecting portion 108b provided in the rear portion of the second injection valve 108 is disposed in a notch 110a provided at the rear end of the insertion tube 110, and a pair of lead wires derived from the conductor connecting portion 108b outside the insertion tube 110. Are passed through the grommet 113 sandwiched between the mating surfaces of the cylinder head 14 and the head cover 15 and are drawn out.
[0062]
On the other hand, the head cover 15 has a cylindrical injector housing 114 which functions as a positioning portion for fitting and holding the first injection valve 107 and also for positioning and holding the second injection valve 108 between the cylinder head 14 and the second injection valve 107. Are formed integrally, and when the head cover 15 is connected to the cylinder head 14, the front end of the injector housing 114 contacts the rear end of the second injection valve 108. Further, a holding plate 115 that holds the rear end 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.
[0063]
The first injection valve 107 is provided with a wiring connector 107a at a rear portion thereof. The first injection valve 107 has a rear end portion sandwiched between an injector housing 114 and a holding plate 115 so that the first injection valve 107 can be connected to a head cover 15a. The wiring connector 107a is arranged so as to face the outside of the head cover 15 when attached.
[0064]
Incidentally, an annular fuel chamber 116 communicating with the inside of 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, which sandwich the fuel chamber 116 from both sides, are formed. 118 is interposed between the first injection valve 107 and the injector housing 114.
[0065]
In addition, a fuel supply passage 119 communicating with the fuel chamber 116 is provided directly on the head cover 15, 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.
[0066]
Further, an annular air chamber 122 communicating with the second injection valve 108 is formed in the injector housing 114 between the front end of the first injection valve 107 and the rear end of the second injection valve 108. The compressed air from the air pump 61 is supplied to the air chamber 122.
[0067]
2 and 10, the lid member 64 of the air pump 61 is provided with a suction pipe 124 to which a hose for guiding air from an air cleaner (not shown) is connected. It is connected to the pump chamber 65 via a built-in reed valve (not shown).
[0068]
The lid member 64 has a built-in poppet valve 125 that opens in response to an increase in the pressure of the pump chamber 65, and compressed air discharged from the air pump 61 passes through the poppet valve 125 and the compressed air supply passage 126. The air is supplied to the air chamber 122.
[0069]
The compressed air supply passage 126 is connected to the lid member 64 at one end so as to be connected to the poppet valve 125, and the other end is connected to the cylinder head 14. A passage 128 is provided directly on the head 14, and a passage 129 is provided directly on the head cover 15 so as to communicate with the passage 128 and the air chamber 122.
[0070]
Moreover, the passage 128 provided directly in the cylinder head 14 is provided on the side opposite to the side on which the two drive rods 46 and 47 of the valve train 38 are disposed, that is, on the intake side and the exhaust side disposed in the first valve chamber 48. The other ends of the two rocker shafts 58 and 59 are provided on the cylinder head 14. In addition, a part of the passage 128 passes near the exhaust port 24. 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 a side opposite to the head side water jacket 103 with respect to the exhaust port 24.
[0071]
Both ends of a cylindrical knock pin 130 that straddles 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. Are directly communicated with each other through the knock pin 130. Moreover, the O-ring 133 surrounding the knock pin 130 is sandwiched between the mating surfaces of the cylinder head 14 and the head cover 15.
[0072]
An orifice 131 is formed in the knock pin 130, and a relief valve 132 connected to the passage 128 on the upstream side of the orifice 131 is attached to the cylinder head 14.
[0073]
Next, the operation of this embodiment will be described. The first and second intake valves 27, 28 and the exhaust valve 29 are arranged such that the operating axes of the valves 27, 28; A second injection valve 108, which is arranged to be openable and closable on the cylinder head 14 in a V-shaped arrangement on the projected view of FIG. 3A and has an axis parallel to the cylinder axis C, directs fuel to the combustion chamber 19 directly. Since the fuel is injected to the cylinder head 14 between the intake valves 27 and 28 and the exhaust valve 29, the fuel injected from the second injection valve 108 can be collected near the center of the combustion chamber 19, Lean combustion is made possible and fuel consumption can be reduced. In addition, since the second injection valve 108 directly injects fuel into the combustion chamber 19 together with the compressed air, the fuel is further atomized and injected into the combustion chamber, thereby enhancing the combustibility and further improving the fuel efficiency. be able to.
[0074]
Also, an odd number of three intake valves 27 and 28 and an exhaust valve 29 are arranged on the cylinder head 14 as a whole, and the ignition plug 26 is arranged so as to line up with the exhaust valve 29 which is the smaller number of valves. Since the spark plug 26 is attached to the cylinder head 14, the degree of freedom in arranging the spark plug 26 can be increased by arranging the spark plug 26 by effectively utilizing an empty space generated around the exhaust valve 29. 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 the fuel consumption by the stratified leaning. Can be planned.
[0075]
Moreover, the ignition 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 and 21 arranged in parallel, and is shifted from the center of the combustion chamber 19. 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 opening end of the first intake port 20 to the combustion chamber 19. A guide wall 142 is provided to guide the intake air to bypass the spark plug 26 and flow.
[0076]
Therefore, 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 19 a of the combustion chamber 19, and flows through the combustion chamber 19 so as to bypass the ignition plug 26. That is, the intake air does not disperse in the combustion chamber 19 due to the collision with the ignition plug 26, and the air-fuel mixture in the combustion chamber 19 is not agitated. Can be further reduced.
[0077]
A cavity 143 is provided at the center of the surface of the piston 17 facing the combustion chamber 19, a second injection valve 108 for directly injecting fuel into the combustion chamber 19, a pair of intake ports 20 and 21, An exhaust port 22 corresponding to the second intake port 21 and a spark plug 26 are disposed on the cylinder head 14 such that the second injection valve 108 is surrounded by the two intake ports 20, 21, the exhaust port 22 and the ignition plug 26. Therefore, by arranging the second injection valve 108 and the ignition plug 26 in the center of the combustion chamber 19 and making the cavity 143 of the piston 17 compact, stratification of the air-fuel mixture and improvement of the compression ratio are achieved. It is possible to improve combustion efficiency and further reduce fuel consumption.
[0078]
Further, an injector 25 including the second injection valve 108 is disposed on the cylinder axis C, and on a projection view on a plane orthogonal to the cylinder axis C, the first intake port 20 and the exhaust port 22 are provided on both sides of the injector 25. Since the second intake port 22 is arranged on one side of the injector 25 on another straight line L2 substantially orthogonal to the straight line L1 connecting the first intake port 20 and the exhaust port 22, the injector 25 Is disposed at the center of the combustion chamber 19, and the flame propagation distance in the combustion chamber 19 is not biased, so that the combustion efficiency can be improved, and the first and second intake ports 20, 21 can be installed. With this arrangement, the air filling efficiency can be improved and the pumping loss can be reduced, and the two intake valves 27 and 28 and one exhaust valve 29 can be connected. 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.
[0079]
Further, since 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, the air-fuel mixture containing fine fuel is sprayed into the cavity 143 to improve the combustion efficiency. It is possible to further improve and further reduce fuel consumption.
[0080]
Further, a protrusion 144 protruding toward the piston 17 is protruded from the ceiling wall 19a of the combustion chamber 19, and the spark plug 26 has a front end protruding from the protrusion 144 into the combustion chamber 19, the tip of the second injection valve 108, ie, the nozzle. Since it is attached to the cylinder head 14 so as to be arranged below the tip of the combustion chamber 108a, the combustion chamber 19 has a structure in which the tip of the spark plug 26 is arranged below the second injection valve 108 in the cavity 143. The influence of swirl in the inside is reduced, the agitation due to the imbalance of the air-fuel mixture is prevented, and a stratified state with a high mixing ratio can be formed at the bottom in the cavity 143, the ignition performance is improved, and the lean burn is further improved. Fuel economy can be reduced. In addition, since the cavity 143 becomes deeper toward the spark plug 26, the richer air-fuel mixture exists on the spark plug 26 side, so that the ignition performance can be further improved.
[0081]
In addition, the intake and exhaust side second rocker arms 44 and 45, which are linked and connected at one end to the intake valves 27 and 28 and the exhaust valve 29 and are 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 respective intake-side and exhaust-side second rocker shafts 58, 59 and are disposed at positions corresponding to one ends of the two rocker shafts 58, 59. 47 is linked to and connected to the other ends of the intake-side and exhaust-side second rocker arms 44 and 45, respectively, so that the intake side and the exhaust of the valve train 38 that drives the intake valves 27 and 28 and the exhaust valve 29. Only the second side rocker arms 44 and 45 and the second side rocker shafts 58 and 59 on the intake side and the exhaust side are arranged on the cylinder head 14 so that the cylinder head is It is possible to enable 14 miniaturization of.
[0082]
The intake-side and exhaust-side drive rods 46, 47 are driven by the rotation of a camshaft 41 disposed on the cylinder block 13 on one axial side of the intake-side and exhaust-side second rocker shafts 58, 59 to rotate. The second rocker arms 44, 45 of the intake side and the exhaust side are arranged between the intake side and the exhaust side second rocker shafts 58, 59. Since the second rocker shafts 58 and 59 on the intake side and the exhaust side can be set narrower because they are linked and connected to the other end, the second rocker shafts 58 and 59 on the intake side and the exhaust side can be set smaller. The size of the cylinder head 14 can be reduced in a direction along a straight line connecting the axes.
[0083]
The spark plug 26 is attached to the cylinder head 14 on the side opposite to the intake side and the 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 and 45 and the intake-side and exhaust-side drive rods 46 and 47 are arranged so as to avoid a portion with little empty space and to prevent a spark plug. By arranging the spark plug 26, the degree of freedom in arranging 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 Combined with the fact that the spray can be collected in the vicinity of the center of the combustion chamber 19, the fuel consumption can be further reduced by the stratified leaning.
[0084]
Between the cylinder head 14 and the head cover 15 that constitute a part of the engine body 11, a first valve operating chamber 48 that accommodates and arranges a part of the valve operating device 38 is formed. 12, the cylinder block 13 and the cylinder head 14 return the lubricated oil of the part accommodated in the first valve chamber 48 of the valve train 38 to the oil pan 12a formed in the lower part of the crankcase 12. A two-valve chamber 49 is formed to extend parallel to the cylinder axis C on the side of the cylinder bore 16. In addition, oil is introduced into the pump case 63 of the air pump 61 disposed below the second valve chamber 49 for introducing 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 chamber 49.
[0085]
Therefore, a part of the oil returning to the oil pan 12a after lubricating a part of the valve gear 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.
[0086]
Further, 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 size of the entire engine can be reduced while reducing the number of parts, and the second dynamic The communication between the valve chamber 49 and the oil introduction hole 85 is facilitated, and the structure for supplying the oil to the air pump 61 can be simplified.
[0087]
In the second valve train chamber 49, 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 train 38 are housed. , The first driven sprocket 52, the first driving sprocket 60 and the second valve chamber 49 accommodating the cam chain 53 are used as an oil return passage, thereby miniaturizing the engine and simplifying the structure for supplying oil to the air pump 61. Can be achieved.
[0088]
The camshaft 41 is accommodated and arranged in the second valve chamber 49, and the camshaft 41 and the camshaft 41 are arranged so that oil splashes separated by the action of centrifugal force with the rotation of the camshaft 41 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 favorably lubricated with the oil flowing in the second valve chamber 49, and the oil droplets scattered by the rotation of the camshaft 41 are reduced. The lubrication of the air pump 61 can be improved by effectively leading to the air pump 61.
[0089]
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 and the camshaft 41 connected to the air pump 61, and the camshaft 41 for driving the air pump 61 is provided. By disposing the power transmission means 89 in the vicinity of the air pump 61, the structure of the power transmission means 89 can be simplified and the size of the engine can be reduced.
[0090]
Moreover, since the camshaft 41 is also disposed in the cylinder block 13 having a relatively small outer shape, it is possible to further contribute to downsizing of the engine, and power transmission means 89 for transmitting the power from the camshaft 41 to the air pump 61. Can be made compact, and the degree of freedom in setting the gear ratio of the air pump 61 is also increased. In addition, since the power transmission means 89 is configured to transmit power by the endless chain 80, the size of the cylinder block 13 is prevented from being increased regardless of the distance between the camshaft 41 and the pump drive shaft 73. However, the number of parts can be reduced.
[0091]
In the cylinder block 13, a protruding wall 36 facing the oil flow direction 137 in the second valve chamber 49 protrudes so as to guide the lower oil in the second valve chamber 49 to the oil introduction hole 85. The lubrication of the air pump 61 can be further improved by effectively guiding the oil to the oil introduction hole 85 by the projecting wall 86.
[0092]
The air pump 61 is of a reciprocating type, and can obtain a relatively high air pressure. Further, the pump drive shaft 73 to which the power from the camshaft 41 for reciprocating the piston 66 in a direction parallel to the cylinder axis C is transmitted is connected to the piston 66 via the Scotch-yoke type crank 84, so that the air pump 61 By making the operating axis and the cylinder axis C parallel to each other and using a scotch-yoke type crank 84 to eliminate the need for a connecting rod, the size of the engine can be reduced.
[0093]
The air pump 61 is provided with a pump chamber 65 disposed on the cylinder head 14 side to generate compressed air in accordance with volume contraction, and an atmospheric pressure disposed on the oil pan 12a side through the oil pan 12a. A piston 66 having both ends facing the chamber 88 is slidably fitted to the pump case 63. The piston 66 is mounted on 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 in the inner periphery of the pump case 63, so that the lubricated oil in the air pump 61 is moved from the atmospheric pressure chamber 88 to the oil pan 12 a by the pumping action of the piston 66. As a result, the operation efficiency and lubrication of the air pump 61 can be improved.
[0094]
The pump case 63 of the air pump 61 is formed integrally with the cylinder block 13 in a cylindrical shape having a bottom with the cylinder head 14 side open, and a lid for closing the opening of the pump case 63 on the cylinder head 14 side in an airtight manner. Since the 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, the number of processing steps for the cylinder block 13 can be reduced.
[0095]
Further, the air pump 61 and the water pump 90 connected to both ends of the pump drive shaft 73 are disposed at positions symmetrical with respect to a plane PL including the cylinder axis C and orthogonal to the pump drive shaft 73. The water pump 90 is driven by the pump drive shaft 73 connected to 61, so that the number of parts can be reduced and the weight can be reduced, and the cost can be reduced by simplifying processing and assembly. In addition, it is possible to suppress the water pump 90 from projecting from the cylinder block, and to avoid increasing the size of the entire cylinder block 13.
[0096]
In addition, the water pump 90 can be arranged near the cylinder block 13 and the cylinder head 14 to be water-cooled, so that the water pipe can be shortened, the pipe can be prevented from being complicated, and the pressure loss in the pipe can be reduced. be able to.
[0097]
Further, since the injector 25 for directly injecting the fuel into the combustion chamber 19 together with the compressed air obtained by the air pump 61 is provided in the cylinder head 14, the air pump 61 is not provided in the cylinder head 14, so that the layout is free. The injector 25 and its piping can be disposed in the cylinder head 14 while increasing the degree of size and miniaturizing the engine. In particular, since the pump chamber 65 of the air pump 61 is arranged on the cylinder head 14 side, the distance between the pump chamber 65 and the injector 25 is relatively short, and the compressed air supply passage 126 for guiding the compressed air from the air pump 61 to the injector 25 is provided. Can be avoided, and the pressure loss in the pipe structure can be suppressed to be small.
[0098]
A part of the compressed air supply passage 126 passes near the exhaust port 24, so that the compressed air flowing through the compressed air supply passage 126 can be heated by the exhaust heat of the exhaust gas flowing through the exhaust port 24. The pump efficiency can be improved by increasing the volume of the compressed air.
[0099]
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 part of the compressed air supply path 126 is formed in the passage 128. Are disposed on the opposite side of the head side water jacket 103 with respect to the exhaust port 24, so that the effect of cooling by the head side water jacket 103 can be minimized from affecting the compressed air flowing through the compressed air supply path 126, High pump efficiency can be maintained even with a water-cooled engine.
[0100]
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 arrangement space including an exhaust pipe connected to the exhaust port 24. It is possible to do.
[0101]
Incidentally, the injector 25 has a first injection valve 107 attached to the head cover 15 so as to inject fuel, and a second injection valve attached to the cylinder head 14 so as to inject fuel directly into the combustion chamber 19 together with compressed air. The first and second injection valves 107 and 108 may be attached to the head cover 15 and the cylinder head 14 in order to perform air-assisted fuel injection. The attaching operation does not become complicated, and the number of parts can be reduced. In addition, since it is sufficient to secure a space for mounting the second injection valve 108 in the cylinder head 14, the cylinder head 14 secures the valve body in which both injection valves are mounted and the valve body in which the second injection valve 108 is mounted to the cylinder head. The required mounting space can be reduced, which can contribute to the downsizing of the cylinder head 14.
[0102]
The first injection valve 107 of the injector 25 is fitted and held in the injector housing 114, but since the injector housing 114 is formed integrally with the head cover 15, the injector housing 114 is provided around the cylinder head 14. Therefore, it is not necessary to dispose the members constituting the above, so that the number of parts can be reduced, and at the same time, it is possible to avoid an increase in the size of the engine and a complicated structure around the engine.
[0103]
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. By simply coupling the head cover 15 to the cylinder head 14, the second injection valve 108 can be positioned with respect to the cylinder head 14, and the work of assembling the second injection valve 108 to the cylinder head 14 becomes easy. Thus, the assembling workability can be improved.
[0104]
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 lead 112 connected to the second injection valve 108 is sandwiched between the cylinder head 14 and the head cover 15. Is drawn out to the outside through the grommet 113, the head cover is attached to the cylinder head 14 in a state in which the second injection valve 108 is attached to the cylinder head 14, and the conductor 112 extending from the second injection valve 108 is inserted through the grommet 113. By connecting the first injection valve 107 and the first injection valve 107 to the head cover 15, the installation including the wiring to both the injection valves 107 and 108 can be completed, and the assemblability can be further improved. it can.
[0105]
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 leading to the injection valve 108 can be shared by the injector housing 114.
[0106]
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 provided directly on 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, increase the size of the engine, and complicate the structure around the engine. Can be avoided.
[0107]
Moreover, a passage 128 which is a part of the compressed air supply passage 126 is provided in the cylinder head 14 at the other end of the second rocker shafts 58 and 59 on the intake side and the exhaust side. By providing a part of the air supply passage 126 in the cylinder head 14, it is possible to avoid an increase in the size of the cylinder head 14.
[0108]
By the way, the camshaft 41 which constitutes a part of the valve operating device 38 for driving the first intake valve 27, the second intake valve 28 and the exhaust valve 29 disposed on the cylinder head 14 includes the cylinder head 14 and the head cover. It is arranged on the cylinder block 13 so as to avoid the space between the 15 blocks. Therefore, the camshaft 41 is not disposed between the cylinder head 14 and the head cover 15, so that the degree of freedom of the layout of the injector housing 114 can be increased, and the fuel supply passage 119 and the passage provided directly on the head cover 15 can be provided. 129 can increase the degree of freedom of the layout.
[0109]
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 a compressed air supply path 126 that supplies compressed air to the second injection valve 108 is provided directly on the head cover 15. Thus, a component for guiding the compressed air to the injector 25 is 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.
[0110]
Further, both ends of a cylindrical knock pin 130 that straddles 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 form 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 are communicated with each other through 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 the injector 25 is supported, no excessive stress is applied to the injector 25. Further, since 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, a dedicated component for connecting the passage is not required, and the number of components can be reduced.
[0111]
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 component is not required for the pressure adjustment, thereby contributing to a reduction in the number of components.
[0112]
Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various design changes can be made without departing from the present invention described in the claims. It is.
[0113]
【The invention's effect】
As described above, according to the first aspect of the present invention, the injection valve for directly injecting fuel into the combustion chamber is inserted into the cylinder head from the head cover side, and the fuel is injected into the cylinder head simply by connecting the head cover to the cylinder head. The valve can be positioned, the work of assembling the injection valve to the cylinder head becomes easy, and the workability of assembling can be improved.
[0114]
According to the second aspect of the invention, when performing the fuel injection by the air assist, the first and second injection valves may be sequentially mounted on the head cover and the cylinder head, so that the assembling work is not complicated. And the number of parts can be reduced. In addition, the mounting space to be secured by the cylinder head can be reduced, which contributes to downsizing of the cylinder head.
[0115]
According to the third aspect of the invention, it is easy to attach the second injection valve to the cylinder head, and the assemblability can be further improved.
[0116]
According to the fourth aspect of the present invention, the head cover is connected to the cylinder head in a state where the second injection valve is mounted on the cylinder head and a lead wire extending from the second injection valve is inserted into the grommet. By attaching the injection valves, the assembly including the wiring to both the injection valves can be completed, and the assemblability can be further improved.
[0117]
Further, according to the invention described in claim 5, a part of the compressed air supply structure for guiding the compressed air to the second injection valve can be shared by the injector housing.
[Brief description of the drawings]
FIG. 1 is a partial longitudinal side view of an engine.
FIG. 2 is a view taken along line 2-2 of FIG. 1 with a head cover removed.
FIG. 3 is a sectional view taken along line 3-3 of FIG. 2;
FIG. 4 is a sectional view taken along line 4-4 of FIG. 3;
FIG. 5 is a sectional view taken along line 5-5 of FIG. 4;
FIG. 6 is an enlarged sectional view of the cylinder head taken along line 6-6 in FIG. 2;
FIG. 7 is a sectional view taken along line 7-7 of FIG. 2;
8 is a sectional view taken along line 8-8 of FIG. 7;
FIG. 9 is a sectional view taken along line 9-9 of FIG. 7;
FIG. 10 is a longitudinal sectional side view of the engine along the line 10-10 in FIG. 2;
[Explanation of symbols]
14 ... cylinder head 15 ... head cover 19 ... combustion chamber 107 ... first injection valve 107a ... wiring connector 108 ... second injection valve 112 ... lead wire 113 ...・ Grommet 114 ・ ・ ・ Injector housing 122 ・ ・ ・ Air chamber

Claims (5)

In a four-cycle direct injection engine that directly injects fuel into the combustion chamber (19), an injection valve (108) that directly injects fuel into the combustion chamber (19) is inserted into the cylinder head (14) from the head cover (15) side, A four-cycle direct injection engine, wherein a positioning portion (114) for positioning the injection valve (108) with respect to the cylinder head (14) is provided on the head cover (15). In a four-cycle direct injection engine for directly injecting fuel into a combustion chamber (19), a first injection valve (107) for injecting fuel is attached to a head cover (15), and the fuel is injected together with compressed air into the combustion chamber (19). A four-cycle direct injection engine characterized in that a second injection valve (108) coaxially connected to the first injection valve (107) is attached to the cylinder head (14) so as to directly inject fuel into the cylinder head (14). The first injection valve (107) is fitted and held in a cylindrical injector housing (114) provided on a head cover (15), and the second injection valve (108) is attached to the cylinder head (14). The four-stroke direct injection engine according to claim 2, wherein the engine is inserted and is sandwiched between a tip of the injector housing (114) and a cylinder head (14). The first injection valve (107) is attached to the head cover (15) with the wiring connector (107a) of the first injection valve (107) facing the outside of the head cover (15), and the second injection valve is provided. The four-stroke cycle according to claim 2 or 3, wherein a conductor (112) connected to the (108) is drawn out through a grommet (113) sandwiched between the cylinder head (14) and the head cover (15). Direct injection engine. 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, 108) in the injector housing (114). The four-stroke direct injection engine according to claim 3, wherein:

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