JP2004301050A - Intake device for direct injection engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce fuel consumption in the low load and low speed range of an engine by making the relationship between the turning quantity and intake volume of a throttle valve in a nonlinear state with a simple constitution in an intake device for a direct injection engine in which a throttle body device adjusting an opening area of an air intake passage with the throttle valve is connected to an intake port of a cylinder head with an injector directly injecting fuel of a quantity corresponding to the turning quantity of the throttle valve to a combustion chamber being arranged, through an intake pipe. <P>SOLUTION: The intake port 23 is formed to have a necessary and sufficient opening area for sucking in the amount of air necessary for the maximum output of the engine. The air intake passage 142 of the throttle body device 140 is formed to have the opening area necessary for sucking in the necessary amount of air for the maximum output of the engine in a state that the plate-like throttle valve 145 turning from a fully closed position to a fully opened position is positioned at an intermediate position between the fully closed position and the fully opened position. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention provides a body having an intake passage, a throttle shaft rotatably supported by the body across the intake passage, and fixed to the throttle shaft so as to adjust an opening area of the intake passage. A throttle body device including a throttle valve and a throttle drum fixed to one end of the throttle shaft outside the body and wound with and connected to a throttle cable, supplies fuel according to the amount of rotation of the throttle valve. The present invention relates to an intake device of a direct injection engine connected via an intake pipe to an intake port of a cylinder head provided with an injector for directly injecting the fuel into the combustion chamber at a predetermined rate.
[0002]
[Prior art]
Conventionally, in a direct injection engine mounted on a vehicle, an amount of fuel corresponding to the operation amount of an accelerator pedal or a throttle grip of a vehicle driver is directly injected into a combustion chamber from an injector disposed in a cylinder head. However, when performing engine output control to reduce fuel consumption by performing lean combustion at low engine load and low engine speed, the amount of operation of the accelerator pedal or throttle grip, that is, the amount of rotation of the throttle valve Does not correspond linearly with the intake volume of the engine.
[0003]
As described above, in order to prevent the rotation amount of the throttle valve and the intake air amount from being linearly associated with each other, the engine intake device disclosed in Patent Document 1 is not a direct injection engine, but is controlled separately from the throttle valve. A valve is provided in the intake system, and the opening of the control valve is controlled by the ECU.
[0004]
[Patent Document 1]
JP-A-11-107788
[0005]
[Problems to be solved by the invention]
By applying the technology disclosed in Patent Document 1 to a direct injection engine, the amount of rotation of the throttle valve and the amount of intake air do not linearly correspond to each other, so that lean combustion is performed in a low engine load and low engine speed range. Although it is possible to reduce the fuel consumption by performing the above, a control valve controlled by the ECU is required in addition to the throttle valve, which increases the number of parts and complicates the configuration.
[0006]
SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and enables the relationship between the amount of rotation of a throttle valve and the amount of intake air to be non-linear with a simple configuration, thereby reducing fuel consumption in a low engine load and low engine speed range. It is an object of the present invention to provide an intake device for a direct injection engine, which makes it possible to achieve the following.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 includes a body having an intake passage, a throttle shaft rotatably supported by the body across the intake passage, and an opening area of the intake passage. A throttle body device comprising: a throttle valve fixed to the throttle shaft so as to be adjusted; and a throttle drum fixed to one end of the throttle shaft outside the body and having a throttle cable wound and connected thereto. However, in an intake device of a direct injection engine connected via an intake pipe to an intake port of a cylinder head provided with an injector for directly injecting fuel into a combustion chamber in an amount corresponding to the amount of rotation of the throttle valve, The intake port has an opening area necessary and sufficient to intake an amount of air required for the maximum output of the engine. The intake passage of the throttle body device is formed such that the plate-shaped throttle valve that can rotate from a fully closed position to a fully open position is located at an intermediate position between the fully closed position and the fully open position. It is characterized in that it is formed so as to have an opening area necessary for inhaling the amount of air required for the maximum output of the engine.
[0008]
According to the configuration of the first aspect of the present invention, the opening area of the intake passage in the throttle body device is required to maximize the engine output before the throttle valve is fully turned to the open side. And the amount of fuel injected from the injector changes in accordance with the amount of rotation of the throttle valve, whereas the amount of rotation of the throttle valve and the intake air in the throttle body device It is possible to make the relationship with the opening area of the passage non-linear, and with a simple configuration using a throttle body device that rotates the throttle valve by operating an inexpensive throttle cable, the amount of rotation of the throttle valve and the amount of intake air are reduced. Is nonlinear, it is possible to reduce fuel consumption in a low engine load and low engine speed range.
[0009]
According to a second aspect of the present invention, in addition to the configuration of the first aspect, the inner surface of the intake pipe is tapered so as to smoothly connect the intake passage and the intake port of the throttle body device. According to such a configuration, the change in the intake air flow rate from the intake passage to the intake port of the throttle body device becomes smooth, and more stable engine output control becomes possible.
[0010]
According to a third aspect of the present invention, in addition to the configuration of the first or second aspect of the present invention, in addition to the configuration of the first or second aspect, the injector supplies an air-fuel mixture consisting of fuel and air to the combustion chamber in an amount corresponding to the amount of rotation of the throttle valve. According to this configuration, the fuel-air mixture is atomized by air and injected into the combustion chamber from the injector. The fuel consumption at low load and low speed can be further reduced while improving the atomization of the fuel and simplifying the structure.
[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. FIG. 7 is a sectional view taken along line 7-7 of FIG. 5, FIG. 8 is a sectional view taken along line 8-8 of FIG. 2, and FIG. 9 is a view showing the relationship between the amount of rotation of the throttle valve and the amount of intake air.
[0013]
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.
[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 and 21 that individually open in a ceiling wall 19a of the combustion chamber 19, an exhaust valve port 22 that opens in the ceiling wall 19a, and first and second An intake port 23 that opens to the upper side surface of the cylinder head 14 by connecting the intake valve ports 20 and 21 of the cylinder head 14 in common, and an exhaust port 24 that opens to the lower side surface of the cylinder head 14 that connects to the exhaust valve port 22. Is provided.
[0016]
Open ends of the first and second intake valve 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 valve port 22 to the combustion chamber 19 are formed. It is opened and closed by an exhaust valve 29. 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.
[0017]
The cylinder head 14 has a position corresponding to the first intake valve port 20 on one end side of the two intake valve ports 20 and 21 in the parallel direction and offset from the center of the combustion chamber 19 and aligned with the exhaust valve 29. The ignition plug 26 facing the combustion chamber 19 is attached.
[0018]
Fuel and air are supplied to 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 intake valves 27, 28 and the exhaust valve 29. In this embodiment, the injector 25 is disposed on the cylinder head 14 coaxially with the cylinder axis C.
[0019]
That is, the injector 25, the pair of intake valve ports 20, 21, the exhaust valve port 22 corresponding to the second intake valve port 21, and the spark plug 26 connect the injector 25 to both the intake valve ports 20, 21 and the exhaust valve. The cylinder head 14 is disposed so as to be surrounded by the port 22 and the spark plug 26.
[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. 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.
[0021]
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.
[0022]
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.
[0023]
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. .
[0024]
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.
[0025]
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.
[0026]
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.
[0027]
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 parts 42a, 43a of the intake-side and exhaust-side first rocker arms 42, 43 so as to be swingable, and are driven at the intake-side and 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.
[0028]
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 be interlocked with and connected to the exhaust valve 29. An exhaust-side second rocker arm 45 having an arm portion 45 a at one end is swingably supported by an exhaust-side second rocker shaft 59.
[0029]
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.
[0030]
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.
[0031]
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.
[0032]
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.
[0033]
8, the pump case 63 of the 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 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.
[0034]
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.
[0035]
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.
[0036]
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.
[0037]
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.
[0038]
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.
[0039]
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.
[0040]
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.
[0041]
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.
[0042]
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.
[0043]
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.
[0044]
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.
[0045]
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.
[0046]
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.
[0047]
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 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 scoop up a part of the oil flowing in the second valve chamber 49 and to operate 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.
[0048]
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.
[0049]
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.
[0050]
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.
[0051]
With particular attention to FIGS. 7 and 8, the injector 25 is configured to inject fuel directly into the combustion chamber 19 together with a first injection valve 107 mounted on the head cover 15 so as to inject fuel. The second injection valve 108 attached to the cylinder head 14 is coaxially connected, and the second injection valve 108 has a nozzle 108 a that enters the combustion chamber 19.
[0052]
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.
[0053]
A lead wire connection portion 108b provided at the rear 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 led out of the lead wire connection portion 108b 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.
[0054]
On the other hand, the head cover 15 has a cylindrical injector housing 114 which fits and holds the first injection valve 107 and also functions as a positioning portion for positioning and holding the second injection valve 108 with the cylinder head 14. 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.
[0055]
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, and the first injection valve 107 is connected to the head cover 15a. The wiring connector 107a is arranged so as to face the outside of the head cover 15 when the wiring connector 107a is attached.
[0056]
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.
[0057]
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.
[0058]
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.
[0059]
The lid member 64 of the air pump 61 is provided with a suction pipe 124 (see FIG. 2) to which a hose for guiding air from an air cleaner (not shown) is connected. The suction pipe 124 is a reed valve built in the lid member 64. (Not shown) and is connected to the pump chamber 65.
[0060]
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.
[0061]
The compressed air supply passage 126 is connected to the lid member 64 such that one end thereof is 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.
[0062]
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.
[0063]
An orifice 131 is formed in the knock pin 130, and a relief valve 132 (see FIG. 2) connected to the passage 128 upstream of the orifice 131 is attached to the cylinder head 14.
[0064]
1 and 3, a throttle body device 140 is connected to the intake port 23 of the cylinder head 14 via an intake pipe 141. The throttle body device 140 includes a body 143 having an intake passage 142, a throttle shaft 144 rotatably supported by the body 143 across the intake passage 142, and an intake passage rotating from a fully closed position to a fully open position. The throttle valve includes a plate-shaped butterfly valve 145 fixed to the throttle shaft 144 so as to adjust the opening area of the throttle 142, and a throttle drum 146 fixed to one end of the throttle shaft 144 outside the body 143. A throttle cable 147 operated by an operation member such as a throttle grip is wound and connected to the throttle drum 146.
[0065]
The body 143 is connected to the intake pipe 141 via a connection band 149 so as to allow the intake passage 142 to communicate with the intake pipe 141. The body 143 includes the throttle shaft 144 and the throttle valve 145. A control unit 148 including a sensor for detecting the amount of rotation of the throttle cable 147, that is, the amount of operation of the throttle cable 147, is attached. The amount of fuel / air mixture injected by the injector 25 corresponds to the amount of rotation of the throttle valve 145. And is controlled by the control unit 148.
[0066]
Incidentally, the intake port 23 of the cylinder head 14 is formed so as to have an opening area necessary and sufficient for inhaling an air amount necessary for the maximum output of the engine. On the other hand, the intake passage 142 of the throttle body device 140 has a maximum output of the engine in a state where the throttle valve 145 that can rotate from the fully closed position to the fully open position is at an intermediate position between the fully closed position and the fully open position. Is formed so as to have an opening area necessary for inhaling an air amount necessary for the air.
[0067]
That is, as shown in FIG. 9, when the throttle valve 145 is rotated from the fully closed position to the fully opened position, the amount of intake air flowing through the intake passage 142 is set to have a smaller opening area than that of the intake passage 142. The maximum intake amount is determined by the flow resistance of the entire intake system including the intake port 23 and the intake amount does not increase even if the throttle valve 145 is operated to the fully open position after reaching the maximum intake amount.
[0068]
The inner surface of the intake pipe 141 is tapered so as to smoothly connect the intake passage 142 and the intake port 23 of the throttle body device 140.
[0069]
Next, the operation of this embodiment will be described. An injector 25 having an axis parallel to the cylinder axis C is disposed on the cylinder head 14 so as to directly inject a mixture of fuel and air into the combustion chamber 19. In addition, the air-fuel mixture can be collected near the center of the combustion chamber 19, so that lean burn can be performed and fuel consumption can be reduced. In addition, since the injector 25 atomizes the fuel by compressed air and directly injects the fuel into the combustion chamber 19, it is possible to improve the atomization of the fuel at a small flow rate and to improve the combustibility while simplifying the structure. Fuel efficiency at low load and low rotation can be further reduced.
[0070]
By the way, the amount of air-fuel mixture injected from the injector 25 is controlled in accordance with the amount of rotation of the throttle valve 145 provided in the throttle body device 140 connected to the intake port 23 of the cylinder head 14 via the intake pipe 141. However, the amount of intake air introduced into the intake port 23 via the throttle body device 140 and the intake pipe 141 and the amount of rotation of the throttle valve 145 have a non-linear relationship as shown in FIG.
[0071]
That is, the intake port 23 of the cylinder head 14 is formed so as to have an opening area necessary and sufficient for inhaling the amount of air required for the maximum output of the engine, while the intake passage 142 of the throttle body device 140 Since the throttle valve 145 is formed at an intermediate area between the fully closed position and the fully open position, the opening area required for inhaling the amount of air required for the maximum output of the engine is formed. Before pivoting the valve 145 to the open side to the maximum, the opening area of the intake passage 142 in the throttle body device 140 is large enough to allow the air required to maximize the engine output to flow. The relationship between the amount of rotation of the throttle valve 145 and the opening area of the intake passage 142 in the throttle body device 140 is nonlinear. It is possible to. Therefore, with a simple configuration using the throttle body device 140 that rotates the throttle valve 145 by operating the inexpensive throttle cable 147, the relationship between the amount of rotation of the throttle valve 145 and the amount of intake air is non-linear, and the low load and low load on the engine are reduced. It is possible to reduce fuel consumption in the rotation range.
[0072]
Moreover, since the inner surface of the intake pipe 141 is formed in a tapered shape so as to smoothly connect the intake passage 142 and the intake port 23 of the throttle body device 140, the inner surface of the intake pipe 141 extends from the intake passage 142 of the throttle body device 140 to the intake port 23. The change in the intake flow velocity becomes smooth, and more stable engine output control becomes possible.
[0073]
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.
[0074]
【The invention's effect】
As described above, according to the first aspect of the present invention, the relationship between the amount of rotation of the throttle valve and the amount of intake air can be determined with a simple configuration using a throttle body device that rotates the throttle valve by operating an inexpensive throttle cable. As a non-linearity, it is possible to reduce fuel consumption in a low engine load and low engine speed range.
[0075]
Further, according to the second aspect of the invention, the change in the intake air flow rate from the intake passage to the intake port of the throttle body device is made smooth, and more stable engine output control becomes possible.
[0076]
Further, according to the third aspect of the present invention, it is possible to improve the atomization of the fuel at a very small flow rate, simplify the structure, and further reduce the fuel consumption at a low load and a low rotation.
[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 sectional view taken along line 8-8 in FIG. 2;
FIG. 9 is a diagram showing the relationship between the amount of rotation of a throttle valve and the amount of intake air.
[Explanation of symbols]
14 ... Cylinder head
19 ... combustion chamber
23 ... intake port
25 ・ ・ ・ Injector
140 ・ ・ ・ Throttle body device
141 ... intake pipe
142 ... intake passage
143 ・ ・ ・ Body
144 ・ ・ ・ Throttle shaft
145 ・ ・ ・ Throttle valve
146 ・ ・ ・ Throttle drum
147 ・ ・ ・ Throttle cable

Claims (3)

A body (143) having an intake passage (142), a throttle shaft (144) rotatably supported by the body (143) across the intake passage (142), and an opening of the intake passage (142); A throttle valve (145) fixed to the throttle shaft (144) so as to adjust the area; and a throttle cable (100) fixed to one end of the throttle shaft (144) outside the body (143). A throttle body device (140) including a throttle drum (146) wound and connected to the combustion chamber (19) directly injects fuel in an amount corresponding to the amount of rotation of the throttle valve (145). Via an intake pipe (141) to an intake port (23) of a cylinder head (14) in which an injector (25) is disposed. In the intake device for a direct injection engine to be connected, the intake port (23) is formed so as to have an opening area necessary and sufficient to intake an amount of air required for the maximum output of the engine, and the throttle body device The intake passage (142) of (140) is provided with the engine in a state where the plate-shaped throttle valve (145) rotatable from a fully closed position to a fully open position is located at an intermediate position between the fully closed position and the fully open position. An intake device for a direct injection engine, which is formed so as to have an opening area necessary for inhaling an air amount necessary for a maximum output of the engine. The inner surface of the intake pipe (141) is tapered so as to smoothly connect the intake passage (142) of the throttle body device (140) and the intake port (23). An intake device for a direct injection engine according to claim 1. The injector (25) injects a mixture of fuel and air directly into the combustion chamber (19) in an amount corresponding to the amount of rotation of the throttle valve (145), and distributes the mixture to the cylinder head (14). 3. The intake device for a direct injection engine according to claim 1, wherein the intake device is provided.

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