JPH05179968A - Engine - Google Patents

Abstract

PURPOSE:To facilitate mounting work of a reed valve and a throttle body to an engine main body, and improve responsiveness from fuel injection up to output. CONSTITUTION:A reed valve 48 and a throttle valve 49 are provided in order toward the upper stream side of intake air so as to be connected to the intake port 42 of an engine main body 20. A fuel injection value 88 is installed to the throttle body 83 of the throttle valve 49. Further, the read valve 48 and the throttle body 83 are fastened together to the engine main body 20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reed valve type engine having a fuel injection valve for injecting fuel into intake air.

[0002]

2. Description of the Related Art A conventional two-cycle engine is disclosed in Japanese Utility Model Publication No. 3-10236. According to this, the intake port is formed in the crankcase which constitutes the engine body, and the reed valve is attached to this intake port. Further, a throttle valve is attached to the upstream end of intake air in the reed valve, and a fuel injection valve for injecting fuel is attached to the inside of the throttle body of the throttle valve. When the engine is operating, first, fuel is injected by the fuel injection valve toward the air taken into the throttle body. Then, the air-fuel mixture is sucked into the crank chamber in the crank case through the reed valve and is pre-compressed there. This precompressed mixture is then drawn into the cylinder through the scavenging port, where it is burned and provided to the engine output.

[0003]

By the way, in the above-mentioned conventional construction, the reed valve and the throttle body are individually attached to the crankcase. Therefore, firstly, there is a problem that the work of attaching the reed valve and the throttle body is complicated. Secondly, since the mounting margin for mounting the throttle body is provided at the upstream end of the intake air in the reed valve, the distance from the fuel injection valve mounted on the throttle body to the crank chamber becomes long, and therefore, By the time the fuel injected from the fuel injection valve reaches the crank chamber, much of this fuel adheres to the inner wall of the throttle body and the like, and there is a problem that the responsiveness from fuel injection to output decreases.

[0004]

SUMMARY OF THE INVENTION The present invention has been made paying attention to the above circumstances, and makes it easy to mount the reed valve and the throttle body on the engine body, and from the fuel injection to the output. The purpose is to improve the responsiveness of.

[0005]

The feature of the present invention for achieving the above-mentioned object is that the reed valve and the throttle valve are sequentially arranged in the upstream side of the intake air so as to be connected to the intake port of the engine body. In the engine in which the fuel injection valve is attached to the throttle body of the throttle valve, the reed valve and the throttle body are jointly fastened to the engine body.

[0006]

[Operation] The operation of the above configuration is as follows. An intake port 42 is formed in the crankcase (engine main body) 20, and a reed valve 48 and a throttle valve 49 are sequentially provided toward the upstream side of the intake so as to be continuous with the intake port 42. When the fuel injection valve 88 is attached to the body 83, the reed valve 48 and the throttle body 83 are fastened together on the crankcase 20 side.

For this reason, firstly, as compared with the prior art in which the reed valve 48 and the throttle body 83 are individually mounted on the crankcase 20 side, this mounting work is simpler. Secondly, in the past, the mounting allowance for mounting the throttle body 83 was provided at the upstream end of intake air in the reed valve 48.
Since it is fastened together on the 0 side, the above mounting allowance becomes unnecessary. Therefore, the distance from the fuel injection valve 88 attached to the throttle body 83 to the inside of the crankcase 20 is correspondingly shortened, and the fuel injected from the fuel injection valve 88 reaches the inside of the crankcase 20 immediately.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) FIGS. 1 to 6 show a first embodiment. In FIG. 2, reference numeral 1 is a motorcycle, which is a vehicle. In addition, the arrow Fr in the drawing indicates the front side thereof, and the following left and right means the direction toward the front side. Motorcycle 1 above
The body frame 2 of has a head pipe 3 at its front end,
A pair of left and right main frames 4 extend rearward and downward from the head pipe 3. A rear arm bracket 5 extends downward from the rear end of each main frame 4.

A front fork 7 is rotatably supported on the head pipe 3. A front wheel 8 is supported on the lower end of the front fork 7, and a handle 9 is attached to the upper end. A rear arm 11 is pivotally supported on the rear arm bracket 5 by a pivot shaft 10 so as to be vertically swingable. A rear wheel 12 is supported on the swinging end of the rear arm 11, and a shock absorber 13 is installed between the rear end of the main frame 4 and the rear arm 11. Further, a seat frame is provided which projects rearward and upward from the rear end of the main frame 4, and the seat 16 is mounted on the seat frame.

An engine 18 is provided below the main frame 4, and the engine 18 is supported on the main frame 4 and the rear arm bracket 5 by the pivot shaft 10 and bolts 19 as described above. The engine 18 is a four-cylinder two-cycle engine, and the left and lower right cylinders 21 project from the front lower surface side of the crankcase 20 toward the lower front. Further, the left and upper right cylinders 22 project from the front upper surface side of the same crankcase 20 toward the upper front, and the crankcase 20, the lower cylinder 21, and the upper cylinder 22 constitute an engine body.

A power transmission device 24 is connected to the rear portion of the crankcase 20, and an output chain wheel 25 of the power transmission device 24 and an input chain wheel 26 attached to the rear wheel 12 are provided.
A transmission chain 27 is wound around the. And
The power of the engine 18 is transmitted to the rear wheels 12 via the transmission chain 27 and the like, so that the motorcycle 1 can travel on the road surface 28. In addition, 30 is a fuel tank, 3
1 is an exhaust pipe.

In FIGS. 1, 3 and 4, a pair of upper and lower crank shafts 34 extending in the left and right direction are supported in the crank chamber 33 in the crank case 20. The lower cylinder 21 has a cylinder 35 that projects downward from the front lower surface side of the crankcase 20.
5 is a left and right bolt 3 in front view with respect to the crankcase 20.
It is fixed by screws 5a and 35a. A cylinder head 36 is attached to the protruding end of the cylinder 35. A piston 38 is slidably fitted into the cylinder 35 on its axis 37, and the piston 38 and the lower crankshaft 34 of the crankshafts 34 are connected by a connecting rod 39.

The cylinder 35, the cylinder head 36,
A space surrounded by the piston 38 is a combustion chamber 41, and an ignition plug 40 facing the combustion chamber 41 is attached to the cylinder head 36. An intake port 42 communicating with the crank chamber 33 is formed in the crankcase 20. The intake port 42 is provided on the crankcase 2 between the left and right bolts 35a, 35a when viewed from the front.
It is formed to 0. The cylinder 35 has a scavenging port 4 for communicating the crank chamber 33 with a combustion chamber 41.
4 are formed. On the other hand, an exhaust port 45 for communicating the combustion chamber 41 to the outside is formed.
The exhaust pipe 31 is connected to 5. Cylinder 3 above
5, a water jacket 46 is formed on the cylinder head 36.

The reed valve 48 and the throttle valve 4 are sequentially arranged toward the upstream side of the intake air so as to be connected to the intake port 42.
9 are provided, and these reed valve 48 and throttle valve 4 are provided.
9 is disposed between the lower cylinder 21 and the upper cylinder 22.
The introduction of traveling wind to the throttle valve 49 is performed by an air introduction pipe projecting forward of the head pipe 3.

1 to 3, the upper cylinder 22 has the same structure as the lower cylinder 21 and has a cylinder 54 and the like. An intake port formed in the crankcase 20 corresponding to the cylinder 54 has a reed valve 48 and a throttle valve 49 provided corresponding to the lower cylinder 21.
Another reed valve 55 and throttle valve 56 having the same configuration as the above are provided, and these reed valve 55 and throttle valve 56 are provided adjacent to the reed valve 48 and the throttle valve 49 for the lower cylinder 21. Further, the piston of the upper cylinder 22 is connected to the upper crankshaft of the crankshaft 34 by a connecting rod. The crankshafts 34 are linked together by a chain, and one of them is connected to the input shaft of the power transmission device 24.

1 and 4 to 6, for convenience of explanation, as shown in FIG. 1, the cylinder 35 of the lower cylinder 21 is used.
The description will be given with the axis 37 of FIG.

The reed valves 48 are paired up and down, and
It is composed of lower reed valves 58 and 59. The lower reed valve 59 has a lower reed valve body 60 having a substantially V-shaped box side cross section. The lower reed valve body 60 is tapered toward the inside of the crank chamber 33, and an outward flange 61 is integrally formed at the base of the lower reed valve body 60. A suction passage 62 is provided inside the lower reed valve body 60. The upstream end opening 62a of the suction passage 62 opens at the base end of the lower reed valve body 60. Further, the downstream end opening 62b of the intake passage 62 is composed of four openings formed in the upper and lower surfaces of the upper and lower reed valve body 60, respectively, and each of the downstream end openings 62b has the same shape and size. However, they are arranged side by side to the left and right. Each of the downstream end openings 62b is openably and closably closed, and a lower valve body 64 is provided. One end of the upper valve body 64 is screwed to a top wall of a base portion of the lower reed valve body 60 by a first bolt 66. Has been done. Further, one end of the lower valve body 64 is provided with the stopper 67 and the second bolt 68.
Thus, the upper and lower reed valve bodies 60 are screwed to the lower surface wall of the base of the same.

On the other hand, the upper reed valve 58 has an upper reed valve main body 70 whose side cross section has an arcuate box shape. The upper reed valve body 70 is tapered toward the inside of the crank chamber 33, and an outward flange 71 is integrally formed at the base of the upper reed valve body 70. A suction passage 72 is provided through the upper reed valve body 70. The upstream end opening 72a of the suction passage 72 opens at the base end of the upper reed valve body 70. Further, the downstream end opening 72b of the suction passage 72 is the same as above.
Each of the downstream end openings 72b has the same shape and size, and is arranged side by side in the left-right direction. A valve body 74 that opens and closes the downstream end opening 72b is provided, and one end of the valve body 74 is screwed together with a stopper 75 to a top wall of a base portion of the upper reed valve body 70 by a third bolt 76.

An outward flange 71 of the upper reed valve 58.
A fitting hole 77 is formed in the fitting hole 77, the lower reed valve body 60 is fitted into the fitting hole 77 from the rear side, and the outward flanges 61 and 71 are overlapped with each other.
In this case, the upper reed valve body 7 is secured by the first bolt 66.
The bottom wall of the base of No. 0 is fastened together with the top wall of the base of the lower reed valve body 60.
8, 59 are firmly integrated. Further, a working hole 78 for inserting the first bolt 66 and a screwing tool for the first bolt 66 is formed in the upper surface wall of the base portion of the upper reed valve body 70, and each working hole 78 is formed in the upper reed valve. It is closed by the valve body 74 attached to the main body 70.

In FIGS. 1, 3 and 4, the outward flanges 61 and 71 are formed with the first mounting bolt 79 and the second mounting bolt 79.
It is removably screwed to the opening edge of the intake port 42 by a mounting bolt 80. The second mounting bolt 80 is also used for screwing the reed valve 55 for the upper cylinder 22. A communication hole 81 for communicating the inside of the throttle valve 49 with the inside of the upper reed valve body 70 is formed in the outward flange 61 of the lower reed valve 59.

The throttle valve 49 has a throttle body 83 connected to the both outward flanges 61 and 72, and an intake passage 84 in the throttle body 83 is provided with a butterfly type throttle valve body 85. The throttle body 83 is detachably screwed to the crankcase 20 side by the first mounting bolt 79 and the second mounting bolt 80. The throttle body 83 is also detachably screwed to the crankcase 20 side by the third mounting bolt 86. That is, the reed valve 48 and the throttle body 83 are detachably fastened together on the crankcase 20 side by the first mounting bolt 79, the second mounting bolt 80, and the third mounting bolt 86.

In FIGS. 5 and 6, a gasket 87 is provided between the outward flanges 61 and 71. By replacing the gasket 87 with another gasket 87 having a different thickness, the relative positions of the upper reed valve 58 and the lower reed valve 59 can be adjusted.

In FIG. 1 and FIG. 3, the fuel injection valve 8 is provided on the upper wall of the throttle body 83 in the substantially left and right center thereof.
8 is attached. When the piston 38 starts to rise from the bottom dead center (shown in FIG. 1) during the operation of the engine 18, the air 89 outside the engine 18 is sucked into the intake passage 84 in the throttle body 83, and the air 8
The fuel 90 is injected by the fuel injection valve 88 toward 9.

Further, the air 89 which is intake air and the fuel 90
The air-fuel mixture 91 is sucked into the crank chamber 33 through the suction passages 62 and 72 of the lower reed valve body 60 and the upper reed valve body 70. At this time, the valve bodies 64 and 74 are not attached to the crank chamber 3
The valve 3 is elastically opened and deformed by the negative pressure in the valve 3, and is automatically opened to allow passage of the air-fuel mixture 91. Also, the valve body 6
If the valves 4 and 74 open too much, these elastically deformed portions come into contact with the stoppers 67 and 75 and the stopper surfaces having arcuate convex shapes formed on the upper and lower surfaces of the intake port 42.
It is prevented by abutting on a stopper surface 92 having a circular arc convex shape formed on the lower surface of the upper reed valve body 70.

When the piston 38 moves up, the air-fuel mixture 91 already sent to the combustion chamber 41 is compressed by the piston 38. When the piston 38 is located near the top dead center, the air-fuel mixture 91 in the combustion chamber 41 is sufficiently compressed and is ignited and burned by the spark plug 40. Then, the piston 38 is pushed down. At this time, the air-fuel mixture 91 sucked into the crank chamber 33 as described above is pre-compressed, and the pre-compressed air-fuel mixture 91 is
Are sent to the combustion chamber 41 through the scavenging port 44.
On the other hand, the combustion gas 9 in the combustion chamber 41 generated by the combustion
3 is exhausted through the exhaust port 45. When the piston 38 moves up again, the above operation is repeated, and power is output from the engine 18.

In FIG. 4, the left-right width dimension 1 of the upper reed valve body 70 is smaller than the width dimension L of the lower reed valve body 60. As a result, the left and right side portions of the upper reed valve body 70 are prevented from interfering with the bolts 35a that fix the cylinder 35 to the crankcase 20 with screws. On the other hand, since the lower reed valve body 60 is located below the upper reed valve body 70 and does not interfere with the bolt 35a, the width L of the lower reed valve body 60 is large regardless of the bolt 35a. The cross-sectional area of the suction passage 62 of the lower reed valve body 60 is increased. As a result, the cross-sectional area of the suction passages 62, 72 is increased as a whole, an increase in the intake resistance of the air-fuel mixture 91 passing through the suction passages 62, 72 is suppressed, and the filling efficiency is improved.

Further, as described above, the suction passages 62, 72
As a result of the increase in the cross-sectional area of the valve as a whole, the amount of the air-fuel mixture 91 passing through each of the downstream end openings 62b and 72b per unit area is reduced. It can be small. Therefore, the responsiveness of the opening and closing operations of the valve bodies 64 and 74 to the operation of the piston 38 is improved, and also in this respect, the performance of the engine 18 is improved. Further, in addition to the difference in width between the upper reed valve 58 and the lower reed valve 59 as described above, the downstream end opening 6 of the suction passage 62 in the upper reed valve 58 is also different.
2b are formed in a line in the left and right direction, whereas the downstream end opening 72b of the suction passage 72 in the lower reed valve 59 is arranged in two lines in the left and right directions.

Therefore, the air-fuel mixture 91 passes through the suction passage 62 of the lower reed valve 59 more than the suction passage 72 of the upper reed valve 58, that is, the air-fuel mixture 91 is located far from the scavenging port 44. Intake passage 62 of reed valve 59
Will be sucked into the crank chamber 33.
Therefore, the air-fuel mixture 91 sucked into the crank chamber 33 through the reed valve 48 is prevented from flowing into the scavenging port 44 in a short-circuited manner.
After being sufficiently mixed in (1), it is fed into the combustion chamber 41 through the scavenging port 44. As a result, ignition and combustion are reliably performed in the combustion chamber 41, and the engine 1
8 performance is improved.

At the portion where the air 89 and the air-fuel mixture 91 are separately flown into the inside of the lower reed valve body 60 and the inside of the upper reed valve body 70, a rectifying plate 94 for rectifying this flow is directed to the outside of the lower reed valve 59. The flange 61 is integrally projected. The current plate 94 prevents the air-fuel mixture 91 that tries to flow into the intake passages 62 and 72 from attempting to cause boundary layer separation, thereby preventing the intake resistance from increasing. Further, by setting the fuel injection of the fuel injection valve 88 to a certain direction and selecting the shape and the projecting direction of the flow straightening plate 94, a desired fuel injection amount to each intake passage 62, 72 of the reed valve 48 can be obtained. Can be distributed.

Each of the upstream end openings 62a and 72a has a long and narrow rectangular shape on the left and right sides, and also has a rectangular shape that is long on the left and right sides as a whole. On the other hand, the intake passage 84 of the throttle body 83 has a pair of left and right passages 84a, 8a.
4a, and each passage 84a has a circular shape. A partition wall 95 is interposed between the passages 84a and 84a. Then, as described above, the intake passage 84 is composed of a pair of left and right passages 84a, 84a in correspondence with the upstream end openings 62a, 72a of the reed valve 48 having a generally rectangular shape that is long in the left and right directions. In this way, the cross-sectional change of the transition portion from the intake passage 84 of the throttle body 83 to the intake passages 62, 72 of the reed valve 48 is made small. Therefore, the air-fuel mixture 9
1 smoothly flows from the intake passage 84 into the intake passages 62 and 72, and an increase in intake resistance is suppressed.

The throttle valve element 85 has circular valve elements 85a and 8a provided in the passages 84a, respectively.
5a, and these valve bodies 85a, 85a can be opened and closed individually. In the low speed region of the engine 18, only one valve body 85a is opened and closed, and in the high speed region, both valve bodies 85a are opened and closed at the same time. In this case, both valve bodies 85a may be integrally opened and closed. It should be noted that the above-described configuration and operation are similar to
The same applies to the reed valve 55 and the throttle valve 56 corresponding thereto. Further, the engine 18 may be composed of a single lower cylinder 21 and an upper cylinder 22 each having a side surface intersecting angle of 90 °. In this case, the lower cylinder 2
The first and upper cylinders 22 drive a single crankshaft 34.
Further, the downstream end openings 62b and 72b of the reed valve 48 are provided.
The number of is not limited to the above embodiment, and may be a single number or a plurality other than this. Further, the engine 18 may be a 4-cycle engine or a diesel engine,
In this case, a reed valve is attached to the intake port formed in the cylinder or cylinder head that is the engine body.

7 to 11 show the second to fourth embodiments. It should be noted that configurations and operations common to the respective embodiments and the first embodiment are designated by common reference numerals in the drawings, description thereof will be omitted, and different portions will be described.

(Second Embodiment) FIGS. 7 and 8 show a second embodiment. According to this, the fuel injection valve 88 is connected to each passage 8
4a, which are attached to the lower surface wall of the throttle body 83. Further, the center of the fuel 90 in the injection direction faces the inside of the lower reed valve body 60. Since the opening area of the suction passage 62 of the lower reed valve body 60 is large, the fuel 90 smoothly flows into the crank chamber 33.

(Third Embodiment) FIGS. 9 and 10 show a third embodiment. According to this, the fuel injection valve 88 is provided for each passage 84a, and these are attached to the left and right side walls of the throttle body 83. Further, the center of the fuel 90 in the injection direction is the lower reed valve body 6
The fuel 90 is supplied to the intake passages 62 and 72 substantially evenly, facing the boundary between the inside of 0 and the inside of the upper reed valve body 70.

(Fourth Embodiment) FIG. 11 shows a fourth embodiment. According to this, the fuel injection valve 88 is connected to each passage 84.
It is provided for each of a and these are attached to the upper surface wall of the throttle body 83.

[0036]

According to the present invention, the reed valve and the throttle valve are sequentially provided toward the upstream side of the intake so as to be connected to the intake port of the engine body, and the fuel injection valve is provided in the throttle body of the throttle valve. When the reed valve and the throttle body are attached together, the reed valve and the throttle body are fastened together to the engine body. Simplified and easy. Secondly, since the throttle body is fastened together with the reed valve to the engine body as described above, the mounting allowance for the throttle body with respect to the reed valve is unnecessary. Therefore, the distance from the fuel injection valve attached to the throttle body to the inside of the engine body is shortened accordingly, and the fuel injected from the fuel injection valve immediately reaches the inside of the engine body, from the fuel injection to the output. Responsiveness is improved. Furthermore, thirdly, there is an effect that the engine can be made compact because the mounting cost of the throttle body is unnecessary as described above.

[Brief description of drawings]

FIG. 1 is a side sectional view of an engine in a state in which an axial center of a lower cylinder is viewed vertically in a first embodiment.

FIG. 2 is an overall side view of the motorcycle according to the first embodiment.

FIG. 3 is a view taken along line 3-3 of FIG. 1 in the first embodiment.

FIG. 4 is a view taken along line 4-4 of FIG. 1 in the first embodiment.

FIG. 5 is a side development view of the reed valve in the first embodiment.

FIG. 6 is a plan development view of the reed valve in the first embodiment.

FIG. 7 is a diagram corresponding to FIG. 1 in the second embodiment.

FIG. 8 is a diagram corresponding to a part of FIG. 3 in the second embodiment.

FIG. 9 is a diagram corresponding to FIG. 1 in the third embodiment.

FIG. 10 is a diagram corresponding to a part of FIG. 3 in the third embodiment.

FIG. 11 is a view corresponding to a part of FIG. 3 in the fourth embodiment.

[Explanation of symbols]

 18 engine 20 crankcase (engine body) 33 crank chamber 42 intake port 48 reed valve 49 throttle valve 54 cylinder 55 reed valve 56 throttle valve 83 throttle body 88 fuel injection valve

Claims (1)

[Claims] 1. An engine in which a reed valve and a throttle valve are sequentially provided toward an upstream side of intake air so as to be connected to an intake port of an engine body, and a fuel injection valve is attached to a throttle body of the throttle valve, An engine in which the reed valve and throttle body are fastened together to the engine body.