JP2004251156A - Fuel injection device for engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To extremely facilitate evaporation treatment of lubricating oil and intermixed fuel components that may be included in excess air discharged from a relief valve, in a fuel injection device for an engine equipped with an injector for directly injecting fuel into a combustion chamber together with compressed air, a compressed air supply source for supplying the compressed air to the injector and the relief valve interposed on the way of a compressed air supplying passage joining the compressed air supply source to the injector. <P>SOLUTION: The excess air discharged from the relief valve 132 is introduced to a lubricated part housing chamber 48 formed inside an engine main body 11 so as to face to a lubricated part. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention provides an injector that directly injects fuel into a combustion chamber together with compressed air, a compressed air supply source that supplies compressed air to the injector, and a compressed air supply path that connects the compressed air supply source and the injector. The present invention relates to a fuel injection device for an engine including a relief valve interposed therebetween.
[0002]
[Prior art]
2. Description of the Related Art A fuel injection device in which a surplus amount of compressed air supplied from an air pump to an injector is released by a relief valve is already known, for example, from Patent Literature 1 and the like.
[0003]
[Patent Document 1]
Japanese Patent No. 3159998
[0004]
[Problems to be solved by the invention]
By the way, in the above-mentioned conventional one, the excess air discharged from the relief valve is configured to be guided to an exhaust pipe that guides exhaust gas from the engine. However, the compressed air supplied to the injector may contain lubricating oil used in the air pump. Further, the excess air discharged from the relief valve may include a fuel component mixed from the injector side. For this reason, surplus air that may contain lubricating oil and entrained fuel components is led to the exhaust pipe when the relief valve is opened. The problem remains in the translation process.
[0005]
The present invention has been made in view of the above circumstances, and has been made in consideration of the fuel injection of an engine in which the evaporation processing of lubricating oil and mixed fuel components which may be contained in excess air discharged from a relief valve is extremely facilitated. It is intended to provide a device.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 includes an injector for directly injecting fuel into a combustion chamber together with compressed air, a compressed air supply source for supplying compressed air to the injector, a compressed air supply source, In a fuel injection device for an engine, comprising a relief valve interposed in the middle of a compressed air supply path connecting the injectors, the lubricated portion accommodating chamber formed in the engine body with the lubricated portion facing. A surplus air discharged from the relief valve is introduced.
[0007]
According to the configuration of the invention as described in claim 1, even if the surplus air discharged from the relief valve contains lubricating oil and a mixed fuel component, the surplus air discharged from the relief valve is: Special attention should be paid to the evaporation process in the exhaust system related to the excess air discharged from the relief valve because it is introduced into the lubricated part storage chamber formed inside the engine body with the lubricated part facing. It is not necessary to pay, and the evaporation process of the lubricating oil and the mixed fuel component becomes extremely easy.
[0008]
According to a second aspect of the present invention, in the configuration of the first aspect, the relief valve is directly attached to an engine body facing the lubricated portion housing chamber. According to this, it is not necessary to form a discharge passage for excess air from the relief valve to the lubricated portion accommodation chamber, and it is possible to avoid an increase in the number of processing steps and the number of parts.
[0009]
According to a third aspect of the present invention, in addition to the configuration of the second aspect, the injector is disposed in a cylinder head constituting a part of the engine body, and the valve train is the lubricated portion housing chamber. A chamber is formed between the cylinder head and a head cover coupled to the cylinder head, and the relief valve is attached to the cylinder head so as to face the valve operating chamber. Thus, the structure of the fuel supply system can be simplified.
[0010]
According to a fourth aspect of the present invention, in addition to the configuration of the third aspect of the invention, a compressed air pump serving as the compressed air supply source is provided in a cylinder block connected to the cylinder head. A passage forming at least a part of a compressed air passage connecting the air pump and the injector is provided directly on the cylinder head, and the relief valve communicating with the passage near the injector attached to the cylinder head is provided on the cylinder head. According to this configuration, the pressure difference between the relief valve and the injector due to the flow resistance of the compressed air can be reduced while shortening the compressed air supply path as much as possible to minimize the pressure loss in the compressed air supply path. Response delay can be reduced, and engine performance can be improved.
[0011]
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.
[0012]
1 to 9 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. 5, FIG. 8 is a longitudinal sectional side view of the engine taken along line 8-8 of FIG. 2, and FIG. 9 is an enlarged sectional view taken along line 9-9 of FIG.
[0013]
First, referring to FIG. 1, an engine body 11 of an overhead valve type four-cycle water-cooled single-cylinder engine includes a crankcase 12, a cylinder block 13 coupled to the crankcase 12, and an opposite side to the crankcase 12. And a head cover 15 connected to the cylinder head 14 on the side opposite to the cylinder block 13, and a motorcycle with the cylinder head 14 side slightly raised forward. Mounted on vehicles.
[0014]
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.
[0015]
The cylinder head 14 has first and second intake valve ports 20, 21 opening to the ceiling surface of the combustion chamber 19, and an opening at the upper side surface of the cylinder head 14 connected to the intake valve ports 20, 21. And a single exhaust valve port 22 opening to the ceiling surface of the combustion chamber 19, and an exhaust port 24 opening to the lower side surface of the cylinder head 14 in connection with the exhaust valve port 22. An injector 25 for directly injecting fuel into the combustion chamber 19 together with the compressed air is disposed so as to be disposed on the axis of the cylinder bore 16, that is, on the cylinder axis C.
[0016]
A first intake valve port 20 and an exhaust valve port 22 are disposed on the cylinder axis C, that is, on both sides of the injector 25 on a projection view on a plane orthogonal to the cylinder axis C, and the first intake valve port 20 and the exhaust valve port are provided. The second intake valve port 21 is disposed on the cylinder axis C, that is, on one side of the injector 25 on another straight line L2 that is substantially orthogonal to the straight line L1 connecting the nozzles 22. A spark plug 26 is attached to the cylinder head 14 so as to face the combustion chamber 19 at a position avoiding the first intake valve port 20, the second intake valve port 21, and the exhaust valve port 22.
[0017]
The cylinder head 14 is provided with first and second intake valves 27 and 28 capable of opening and closing the first and second intake valve ports 20 and 21, respectively, so as to be capable of opening and closing, and opening and closing the exhaust valve port 22. A possible exhaust valve 29 is arranged for opening and closing operation.
[0018]
According to such an arrangement of the injector 25, the first and second intake valve ports 20, 21, the exhaust valve port 22, and the spark plug 26, the injector 25 is disposed at the center of the combustion chamber 19 and And the combustion efficiency can be improved, and the provision of the first and second intake valve ports 20, 21 can improve the air charging efficiency and reduce the pumping loss. In addition, the spark plug 26 can be arranged while easily avoiding interference with the first and second intake valves 27 and 28 and one exhaust valve 29, and the ignition plug 26 can be arranged close to the injector 25. The combustion efficiency can be improved as much as possible.
[0019]
The first and second intake valves 27 and 28 are respectively slidably fitted to guide cylinders 30 fixed to the cylinder head 14, and are mounted on upper end portions of both intake valves 27 and 28 protruding from the guide cylinders 30. A valve spring 32 is provided between the fixed retainer 31 and the cylinder head 14, respectively, and both intake valves 27 and 28 are urged in a valve closing direction by a 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.
[0020]
With further reference to FIGS. 5 to 7, the first and second intake valves 27 and 28 and the exhaust valve 29 are driven to be opened and closed 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. An exhaust-side first rocker arm 43 that moves, an intake-side second rocker arm 44 having a pair of pressing arms 44a and 44b that contact the first and second intake valves 27 and 28, and a pressing arm that contacts the exhaust valve 29. A second rocker arm 45 on the exhaust side having a portion 45a and a swinging motion of the first rocker arm on the intake side transmitted to the second rocker arm on the intake side are provided between the first and second rocker arms on the intake side. And an exhaust-side push rod provided between the exhaust-side first and second rocker arms 43 and 45 so as to transmit the swinging motion of the intake-side push rod 46 and the exhaust-side first rocker arm 43 to the exhaust-side second rocker arm 45. 47.
[0021]
Between the cylinder head 14 and the head cover 15, a lubricated part that accommodates and arranges the intake-side and exhaust-side second rocker arms 44 and 45 and the intake-side and exhaust-side push rods 46 and 47 of the valve train 38. A valve operating chamber 48 is formed as an accommodation chamber, and an oil ejection hole 36 is provided in the head cover 15 in order to lubricate a portion of the valve operating apparatus 38 which is accommodated in the valve operating chamber 48.
[0022]
In the crankcase 12, the cylinder block 13 and the cylinder head 14 of the engine body 11, oil lubricating the portion of the valve train 38 housed in the valve train 48 is formed in the lower part of the crankcase 12. An oil return passage 49 for returning to the pan 12a (see FIG. 1) is provided so as to extend parallel to the cylinder axis C on the side of the cylinder bore 16.
[0023]
The camshaft 41 of the valve train 38 is arranged in the cylinder block 13 so as to be accommodated in the oil return passage 49 while avoiding the valve train 48 between the cylinder head 14 and the head cover 15. 13 and a cover 50 which is fastened to the cylinder block 13 so as to form an outer surface of the oil return passage 49, both ends of a camshaft 41 having an axis parallel to the crankshaft via ball bearings 51, 51. Supported rotatably.
[0024]
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.
[0025]
In the oil return passage 49, a first driven sprocket 52, a first driving sprocket 60 (see FIG. 1), and an endless cam chain 53 are provided to transmit the power from the crankshaft 10 at a reduced speed of １ ／. The first driven sprocket 52 is housed therein and is relatively non-rotatably coupled to the camshaft 41, the first driving sprocket 60 is relatively non-rotatably coupled to the crankshaft 10, and the cam chain 53 is connected to the first driving sprocket 60 and the first driving sprocket 60. It is wound around one driven sprocket 52.
[0026]
The intake-side and exhaust-side first rocker arms 42 and 43 have rollers 54 and 55 that come into rolling contact with the intake-side and exhaust-side cams 39 and 40 from the cylinder head 14 side, respectively. 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. .
[0027]
On the other hand, in the cylinder head 14 in the valve operating chamber 48, intake-side and exhaust-side second rocker shafts 58 and 59 having axes parallel to the camshaft 41 are arranged on both sides of the injector 25. The intake-side second rocker arm 44, which is supported and has a pair of bifurcated pressing arms 44a and 44b, is swingably supported by an intake-side second rocker shaft 58, and the exhaust-side second rocker arm 45 is exhausted. The second rocker shaft 59 is pivotally supported by the second side rocker shaft 59.
[0028]
In addition, the suction-side second rocker arm 44 is integrally provided with a bowl-shaped pressure receiving portion 44c which is open to the cylinder block 13 side on the side opposite to the pressing arm portions 44a and 44b with respect to the suction-side second rocker shaft 58, and is provided on the exhaust side. On the exhaust side second rocker arm 45 opposite to the pressing arm 45a with respect to the second rocker shaft 59, a bowl-shaped pressure receiving portion 45b opened toward the cylinder block 13 is integrally provided.
[0029]
The intake-side and exhaust-side push rods 46 and 47 extend from the valve operating chamber 48 to a part of the inside of the oil return passage 49, and the spherical ends at one end of the intake-side and exhaust-side push rods 46 and 47 are The spherical ends of the other end sides of the intake and exhaust push rods 46, 47 are fitted to the pressing portions 42a, 43a of the first rocker arms 42, 43 on the intake side and the exhaust side, respectively. The rocker arms 44 and 45 are fitted to the pressure receiving portions 44c and 45b of the second rocker arms 44 and 45 in a swingable manner.
[0030]
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 push 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. As the exhaust-side first rocker arm 43 swings, the exhaust-side push rod 47 operates in its axial direction, and the exhaust-side second rocker arm 45 swings accordingly, whereby the exhaust valve 29 is opened and closed. become.
[0031]
By the way, the injector 25 is supplied with compressed air from a compressed air pump 61 as a compressed air supply source. The compressed air pump 61 reciprocates the piston 66 in a direction parallel to the cylinder axis C. It is configured as a reciprocating type, and is disposed below the cylinder block 13 on the side corresponding to the exhaust port 24 provided in the cylinder head 14. Moreover, in the cylinder block 13, a working chamber 62 disposed below the cylinder bore 16 is formed so as to be connected to the oil return passage 49 in a substantially L-shape in a plane perpendicular to the cylinder axis C. The air pump 61 is disposed below the oil return passage 49 in a continuous portion between the oil return passage 49 and the working chamber 62.
[0032]
8, the pump case 63 of the compressed air pump 61 has an axis parallel to the cylinder axis C and is formed integrally with the cylinder block 13 in a closed-end cylindrical shape with the cylinder head 14 side opened. A lid member 64 for airtightly closing the opening of the pump case 63 on the cylinder head 14 side is fastened to the cylinder block 13.
[0033]
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.
[0034]
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.
[0035]
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.
[0036]
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.
[0037]
The pump drive shaft 73 is connected to a piston 66 of the compressed air pump 61 via a scotch / yoke type crank 84. The scotch / yoke type crank 84 is a sliding piece slidably fitted to the piston 66. 68, the tip of an eccentric shaft 73a projecting from an eccentric position of one end of the pump drive shaft 73 is connected. 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 compressed air pump 61 The pump is reciprocated in the axial direction in the pump case 63 so as to increase or decrease the volume.
[0038]
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 therefrom.
[0039]
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.
[0040]
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 oil accumulated in a lower portion in the valve operating chamber 48, and a passage that opens to the working chamber 62 through the passage 134. Although 135 is provided in the cylinder block 13, 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.
[0041]
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 compressed air pump 61 with respect to the bearing member 69, and includes a pump axis 73 including a cylinder axis C. The compressed air pump 61 and the water pump 90 are arranged at positions symmetrical with respect to a plane PL perpendicular to the plane PL.
[0042]
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.
[0043]
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. A plurality of magnets 96 are fixed to the rotor 95 inserted into the bottomed cylindrical portion 92a in this manner. 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. A plurality of magnets 98 are 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.
[0044]
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.
[0045]
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.
[0046]
In the upper side wall of the pump case 63 in the compressed air pump 61, an oil introduction hole 85 for guiding a part of the oil flowing through the oil return passage 49 into the pump case 63 for lubrication is formed so as to communicate with the oil return passage 49. Provided. By the way, the rotation in the oil return passage 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 oil return passage 49 and separate and scatter the oil by the action of centrifugal force. In addition, a part of the oil supplied from the oil supply path 37 is separated and scattered by the action of centrifugal force. The relative position has been set.
[0047]
The width of the portion of the oil return passage 49 corresponding to the valve gear 38 is formed to be larger than that of the other portion, and corresponds to the intake cam 39 and the exhaust cam 40 of the camshaft 41. A protruding wall 86 that surrounds the portion to be formed in a substantially semicircular shape is integrally formed with the cylinder block 13 so as to face the oil flow direction 137 in the oil return passage 49. The return hole 85 is disposed 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 through the oil return passage 49 to the oil introduction hole 85.
[0048]
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.
[0049]
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.
[0050]
Paying particular attention to FIG. 7, the injector 25 has an air fuel injection valve 107 having a nozzle 106 that enters the combustion chamber 19 and attached to the cylinder head 14, and injects fuel into the air fuel injection valve 107 from the rear. The fuel injection valve 107 is connected to the air fuel injection valve 107 in such a manner that the fuel injection valve 107 directly injects the fuel into the combustion chamber 19 together with the compressed air.
[0051]
The cylinder head 14 has a fitting hole 109 for tightly fitting the nozzle 106, and an insertion cylinder 110 having an inner diameter larger than the fitting hole 109 and coaxially connected to the fitting hole 109. The air fuel injection valve 107 is provided coaxially with the cylinder axis C. The air fuel injection valve 107 has an annular step formed between the fitting hole 109 and the insertion cylinder 110 while the nozzle 106 is airtightly fitted into the fitting hole 109. It is inserted into the insertion tube 110 until it comes into contact with the portion 111 via the wave spring washer 123.
[0052]
In addition, the wire connecting portion 107a provided at the rear portion of the air fuel injection valve 107 is disposed in a notch 110a provided at the rear end of the insertion tube 110, and a pair of wires derived from the wire connecting portion 107a outside the insertion tube 110. Are penetrated to the outside through the grommet 113 sandwiched between the mating surfaces of the cylinder head 14 and the head cover 15.
[0053]
On the other hand, a cylindrical injector housing 114 for fitting and holding the fuel injection valve 108 and for holding the air fuel injection valve 107 between the head cover 15 and the cylinder head 14 is formed integrally with the head cover 15. At the time of connection to the cylinder head 14, the front end of the injector housing 114 comes into contact with the rear end of the air fuel injection valve 107. A holding plate 115 for holding the rear end of the fuel injection valve 108 between the injector housing 114 and the injector housing 114 is fastened to the rear end of the injector housing 114.
[0054]
An annular fuel chamber 116 communicating with the fuel injection valve 108 is formed between the injector housing 114 and the fuel injection valve 108, and a pair of seal members 117 and 118 sandwiching the fuel chamber 116 from both sides are used for fuel injection. It is interposed between the valve 108 and the injector housing 114.
[0055]
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.
[0056]
An annular air chamber 122 communicating with the air fuel injection valve 107 is formed between the front end of the fuel injection valve 108, the rear end of the air fuel injection valve 107, and the injector housing 114. The compressed air from the compressed air pump 61 is supplied to the chamber 122.
[0057]
2 and 8, the lid member 64 of the compressed 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. Is connected to the pump chamber 65 via a reed valve (not shown) built in the pump.
[0058]
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. The compressed air discharged from the compressed air pump 61 is supplied to the poppet valve 125 and the compressed air supply passage 126. Is supplied to the air chamber 122.
[0059]
The compressed air supply passage 126 is provided directly to the cylinder head 14 so as to be connected to the poppet valve 125 and connected to the lid member 64 at one end and to the other end of the pipe member 127. And a passage 129 provided directly to the head cover 15 so as to communicate with the passage 128 and the air chamber 122.
[0060]
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.
[0061]
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.
[0062]
By using the knock pin 130 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. Moreover, 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 special component is not required for the pressure adjustment, which can contribute to a reduction in the number of components.
[0063]
The relief valve 132 faces the valve operating chamber 48 formed between the cylinder head 14 and the head cover 15 in the engine body 11 and is directly attached to the cylinder head 15. The compression valve connects the compressed air pump 61 and the injector 25. The air passage 126 is attached to the cylinder head 14 near the injector 25 so as to constitute at least a part (a part in this embodiment) of the air passage 126 and communicate with a passage 128 provided directly in the cylinder head 14.
[0064]
In FIG. 9, a mounting boss 144 having a relief passage 142 communicating with the passage 128 and a screw hole 143 coaxially connected to the relief passage 142 is provided in the cylinder head 14 at a portion facing the valve operating chamber 48. It is provided integrally so as to protrude to the 48 side.
[0065]
The valve housing 145 of the relief valve 132 has a valve hole 146 coaxially connected to the relief passage 142 at an inner end closing portion, and is formed in a cylindrical shape with a bottom. Is screwed into the screw hole 143 with an annular seal member 147 interposed therebetween. Further, a valve seat 148 having the valve hole 146 facing the center is formed on the inner surface of the inner end closing portion of the valve housing 145, and the valve body accommodated in the valve housing 145 so as to be seated on the valve seat 148. A spring 151 is contracted between the spring housing 149 and a spring receiving member 150 fixed to an outer end of the valve housing 145.
[0066]
Thus, when the pressure of the passage 128 in the compressed air supply passage 126 exceeds a value determined by the spring load of the spring 151, the valve element 149 separates from the valve seat 148, and excess air from the passage 128 is released from the valve hole 146, The valve body 149 and the valve housing 145 are guided to the valve chamber 48 through the opening 152 provided in the spring receiving member 150 and the gap between the valve housing 145 and the valve housing 145.
[0067]
Next, the operation of this embodiment will be described. The crankcase 12, the cylinder block 13, and the cylinder head 14 are provided with oil that lubricates a portion of the valve train 38 housed in the valve train chamber 48, An oil return passage 49 for returning to the oil pan 12a formed in the lower part is formed so as to extend parallel to the cylinder axis C on the side of the cylinder bore 16. Moreover, an oil introduction hole 85 for introducing a part of the oil flowing through the oil return passage 49 into the pump case for lubrication is provided in the pump case 63 of the compressed air pump 61 disposed below the oil return passage 49. , Which are provided so as to communicate with the oil return passage 49.
[0068]
Therefore, a part of the oil that returns 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 compressed air pump 61, and the lubrication of the compressed air pump 61 is simplified with a simple structure. Can be reliably achieved.
[0069]
In addition, since the pump case 63 is integrally formed with the cylinder head 13 and the cylinder block 13 having a smaller outer shape than the crankcase 12 which cooperate with the engine body 11, the number of parts can be reduced and the overall size of the engine can be reduced. The communication between the oil return passage 49 and the oil introduction hole 85 can be facilitated, and the structure for supplying oil to the compressed air pump 61 can be simplified.
[0070]
In the oil return passage 49, a first driven sprocket 52, a first driving sprocket 60, and a cam chain 53 for transmitting power from the crankshaft 10 to the camshaft 41 of the valve train 38 are accommodated. By using the portion for accommodating the first driven sprocket 52, the first driving sprocket 60 and the cam chain 53 as the oil return passage 49, it is possible to reduce the size of the engine and to simplify the structure of supplying oil to the compressed air pump 61. .
[0071]
Further, the camshaft 41 is accommodated and arranged in the oil return passage 49, and the camshaft 41 and the oil are arranged so that the oil droplets 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 introduction hole 85 is set, the camshaft 41 is satisfactorily lubricated with the oil flowing through the oil return passage 49, and the oil droplets scattered by the rotation of the camshaft 41 are compressed by a compressed air pump. Thus, the lubrication of the compressed air pump 61 can be improved.
[0072]
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 compressed air pump 61 and the camshaft 41, and a camshaft for driving the compressed air pump 61 is provided. By arranging 41 near the compressed air pump 61, the structure of the power transmission means 89 can be simplified and the size of the engine can be reduced.
[0073]
In addition, 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 for transmitting the power from the camshaft 41 to the compressed air pump 61. 89 can be made compact, and the degree of freedom of setting the gear ratio of the compressed air pump 61 is 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.
[0074]
In the cylinder block 13, a protruding wall 36 facing the oil flow direction 137 in the oil return passage 49 is provided so as to project oil at a lower portion in the oil return passage 49 to the oil introduction hole 85. The lubrication of the compressed air pump 61 can be further improved by effectively guiding the oil to the oil introduction hole 85 by the projecting wall 86.
[0075]
The compressed air pump 61 is of a reciprocating type, and can obtain a relatively high air pressure. Moreover, 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 and yoke type crank 84. By making the operating axis of 61 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.
[0076]
Further, the compressed air pump 61 is provided with a pump chamber 65 arranged on the cylinder head 14 side to generate compressed air in accordance with volume contraction, and a large chamber arranged on the oil pan 12a side through the oil pan 12a. A piston 66 having both ends facing the air pressure chamber 88 is slidably fitted to the pump case 63. The piston 66 is mounted on the outer periphery of the piston 66 and has an atmospheric pressure lower than that of the piston ring 138 sliding on the inner periphery of the pump case 63. On the side of the chamber 88, the oil introduction hole 85 opens in the inner periphery of the pump case 63, so that the lubricated oil in the compressed air pump 61 is pumped by the piston 66 from the atmospheric pressure chamber 88 to the oil pan 12 a. As a result, the compressed air pump 61 is smoothly discharged to the side, and the operation efficiency and lubrication of the compressed air pump 61 can be improved.
[0077]
Further, the compressed air pump 61 and the water pump 90 connected to both ends of the pump drive shaft 73 are arranged at positions that are plane-symmetric with respect to a plane PL that includes the cylinder axis C and that is orthogonal to the pump drive shaft 73. By driving the water pump 90 with the pump drive shaft 73 connected to the air pump 61, the number of parts can be reduced and the weight can be reduced, and the cost can be reduced by simplifying the processing and assembly. In addition, it is possible to suppress the water pump 90 from projecting from the cylinder block, and to prevent the entire cylinder block 13 from being enlarged.
[0078]
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.
[0079]
Further, since the injector 25 for directly injecting fuel into the combustion chamber 19 together with the compressed air obtained by the compressed air pump 61 is provided in the cylinder head 14, the compressed air pump 61 is not provided in the cylinder head 14, so that The injector 25 and its piping can be arranged in the cylinder head 14 while increasing the degree of freedom in layout and miniaturizing the engine. In particular, since the pump chamber 65 of the compressed air pump 61 is disposed on the cylinder head 14 side, the distance between the pump chamber 65 and the injector 25 is relatively short, and compressed air supply for guiding compressed air from the compressed air pump 61 to the injector 25 is provided. It is possible to avoid complication of the pipe structure including the passage 126, and to reduce the pressure loss in the pipe structure.
[0080]
The fuel injection valve 108 of the injector 25 is fitted and held in the injector housing 114. Since the injector housing 114 is formed integrally with the head cover 15, the injector housing 114 is formed around the cylinder head 14. Therefore, it is not necessary to dispose a member to be used, so that it is possible to reduce the number of parts and to avoid an increase in the size of the engine and a complicated structure around the engine.
[0081]
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 also reduce the number of parts, increase the size of the engine, and complicate the structure around the engine. Can be avoided.
[0082]
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.
[0083]
Excess air discharged from the relief valve 132 provided in the middle of the compressed air supply passage 126 is directed to the portion to be lubricated, that is, the portion of the valve operating device 38 that is accommodated in the valve operating chamber 48 and faces the engine main body 11. It is introduced into the valve operating chamber 48 formed between the cylinder head 14 and the head cover 15, and even if the excess air discharged from the relief valve 132 contains lubricating oil or mixed fuel components, It is not necessary to pay special attention to the evaporating process in the exhaust system related to the excess air discharged from the valve 132, and the evaporating process of the lubricating oil and the mixed fuel component becomes extremely easy.
[0084]
Further, since the relief valve 132 faces the valve operating chamber 48 and is directly attached to the cylinder head 14 of the engine body 11, it is not necessary to form a discharge passage for excess air from the relief valve 132 to the valve operating chamber 48. Thus, an increase in the number of processing steps and the number of parts can be avoided.
[0085]
Further, since the injector 25 is provided on the cylinder head 14 and the relief valve 132 is attached to the cylinder head 14 so as to face the valve operating chamber 48, the structure of the fuel supply system can be simplified.
[0086]
In addition, a compressed air pump 61 is provided in the cylinder block 13 connected to the cylinder head 14, and a passage 128 which forms a part of a compressed air passage 126 connecting the compressed air pump 61 and the injector 25 is formed in the cylinder head 14. Since the relief valve 132 which is directly provided and communicates with the passage 128 in the vicinity of the injector 25 is attached to the cylinder head 14, the compressed air supply passage 126 is shortened as much as possible, and the pressure loss in the compressed air supply passage 126 is suppressed. The pressure difference and the response delay between the relief valve 132 and the injector 25 due to the flow resistance of the compressed air can be reduced, and the engine performance can be improved.
[0087]
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.
[0088]
【The invention's effect】
As described above, according to the first aspect of the present invention, it is not necessary to pay special attention to the evaporating process in the exhaust system relating to the excess air discharged from the relief valve, and the evaporating of the lubricating oil and the mixed fuel component can be performed. The translation process becomes extremely easy.
[0089]
According to the second aspect of the present invention, it is not necessary to form a discharge passage for excess air from the relief valve to the lubricated portion accommodation chamber, and it is possible to avoid an increase in the number of processing steps and the number of parts.
[0090]
According to the third aspect of the invention, the structure of the fuel supply system can be simplified.
[0091]
According to the fourth aspect of the present invention, the pressure difference and the response delay between the relief valve and the injector due to the flow resistance of the compressed air are reduced while the compressed air supply path is made as short as possible to reduce the pressure loss in the compressed air supply path. And engine performance can be improved.
[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. 2;
FIG. 6 is a sectional view taken along line 6-6 in FIG. 5;
FIG. 7 is a sectional view taken along line 7-7 of FIG. 5;
FIG. 8 is a longitudinal sectional side view of the engine taken along line 8-8 in FIG. 2;
FIG. 9 is an enlarged sectional view taken along line 9-9 of FIG. 2;
[Explanation of symbols]
11 Engine body
14 ... Cylinder head
13 ... Cylinder block
15 ・ ・ ・ Head cover
19 ... combustion chamber
25 ・ ・ ・ Injector
48: Valve chamber as a chamber to be lubricated
61 Compressed air pump as compressed air supply source
126 ... Compressed air supply path
128 ... passage
132 ・ ・ ・ Relief valve

Claims (4)

An injector (25) for directly injecting fuel into the combustion chamber (19) together with compressed air; a compressed air supply source (61) for supplying compressed air to the injector (25); a compressed air supply source (61); In a fuel injection device for an engine including a relief valve (132) interposed in a compressed air supply passage (126) connecting between injectors (25), a lubricated portion is exposed in an engine body (11). A fuel injection device for an engine, wherein surplus air exhausted from the relief valve (132) is introduced into the lubricated portion housing chamber (48). The fuel injection device for an engine according to claim 1, wherein the relief valve (132) is directly attached to the engine body (11) facing the lubricated portion housing chamber (48). The injector (25) is disposed on a cylinder head (14) that constitutes a part of the engine body (11), and the valve operating chamber (48) that is the chamber to be lubricated is housed in the cylinder head (14). And a head cover (15) coupled to the cylinder head (14), wherein the relief valve (132) is attached to the cylinder head (14) facing the valve train chamber (48). 3. The fuel injection device for an engine according to claim 2, wherein: A compressed air pump (61), which is a compressed air supply source, is provided in a cylinder block (13) connected to the cylinder head (14), and a space between the compressed air pump (61) and the injector (25) is provided. A passage (128) constituting at least a part of the compressed air passage (126) is provided directly on the cylinder head (14), and the passage (128) is provided near the injector (25) attached to the cylinder head (14). 4. The fuel injection system according to claim 3, wherein the relief valve (132) leading to the cylinder head (128) is mounted on the cylinder head (14).

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