JPH02218804A - Direct acting engine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention provides three intake pulps or three exhaust valves that are arranged adjacent to each other so as to surround the center of a bore, and these three intake and This relates to a direct-acting engine that opens and closes exhaust valves using a common camshaft.

(Background of the invention) In order to expand the intake/exhaust passage area of intake/exhaust valves,
It is contemplated to provide three or more intake valves or three exhaust valves. In this case, three intake pulps or three exhaust valves are arranged to surround the center of the bore, and three adjacent intake pulps are connected to one common camshaft.
It is possible to use a direct-acting type in which three adjacent exhaust valves are opened and closed by a common camshaft. In this way, when three adjacent intake and exhaust valves are opened and closed using a common camshaft, conventionally the center line of the valve shafts of the three intake and exhaust valves that are opened and closed using a common camshaft is the center of the camshaft. It was made to almost intersect with the axis. That is, the valve lifters of each valve were arranged in parallel in the camshaft direction.

However, if this is done, the valve springs coaxially arranged on each valve will be lined up in the camshaft direction, so each valve must be spaced apart in the camshaft direction to avoid interference between the valve springs. , the problem arises that the engine width in the camshaft direction increases.

Therefore, it is conceivable to separate the upper ends of each valve and open and close them using a rocker arm, but in this case, the width in the direction orthogonal to the engine camshaft increases because of the rocker arm.

(Objective of the Invention) The present invention was made in view of the above circumstances, and is directed to a direct-acting engine in which three intake and exhaust valves surrounding the center of the bore are opened and closed by a common camshaft. It is an object of the present invention to provide a direct-acting engine capable of suppressing the engine width in the camshaft direction and the direction perpendicular to the camshaft direction by preventing interference between the comrades. is a direct-acting engine in which three adjacent intake or exhaust valves surrounding the center of the bore are opened and closed by a common camshaft, and the valves are coaxially attached to each of the three intake and exhaust valves. Among the springs, the upper part of the valve spring of the center intake/exhaust valve is offset toward the outside of the cylinder than the upper part of the valve spring of the intake/exhaust valves on both sides with respect to a plane passing through the center of the bore and parallel to the camshaft. On the other hand, this is achieved by a direct-acting engine characterized in that the center of the camshaft is offset toward the bore center side with respect to the extension line of the valve shaft of the central intake/exhaust valve.

(Embodiment) Fig. 1 is a valve arrangement diagram in an embodiment of the present invention, Fig. 2 is a valve arrangement diagram in an embodiment of the present invention.
The figure is a side view showing the engine and throttle interlocking mechanism taken along the line II-II, FIG. 3 is a perspective view of the intake passage,
FIG. 4 is a perspective view of the valve mechanism.

In FIG. 1, reference numeral 10 is a cylinder, 12 is the bore center of this cylinder lO, and 14 is an axis of symmetry passing through this bore center 12. 16 (16A to 16D) are four intake valves, the intake valve 16A is located above the bore center 12,
The intake valve 16B is located on the axis of symmetry 14. Further, other intake valves 16C and 116D are arranged to sandwich the valves 16A and 16B on the axis of symmetry 14. As a result, the three intake valves 16B, C, and D are located adjacent to each other so as to surround the bore center 12.

18 (18A to 18C) are three exhaust valves,
The exhaust valve 18A is arranged on the axis of symmetry 14, and the other exhaust valves 18B and 18C are arranged to sandwich this valve 18A. That is, these exhaust valves 18 are adjacent to each other so as to surround the bore center 12. 20 (2
OA, 20B) are spark plugs, these are intake valve 1
They are arranged to sandwich 6A.

In FIG. 2, 20 is a piston that slides within the cylinder 10, 22 is a cylinder head, and 24 is a combustion chamber. The four intake valves 16 are inclined parallel to one side (left side) of the cylinder head 22 as shown in Fig. 2.4, and the three exhaust valves 18 are inclined parallel to the other side (right side) of the cylinder head 22. is inclined to. The ignition column 20 is disposed substantially perpendicularly to a space formed between the intake valve 16 and the exhaust valve 18, which is shaped like a square in side view. Reference numeral 25 indicates a valve lifter on the intake side, and reference numeral 26 indicates a valve lifter on the exhaust side. Each of these valve lifters 25 and 26 is approximately designed to cover the valve shaft ends of the four intake valves 16 and the valve shaft ends of the three exhaust valves 18, respectively. It is formed in the shape of a lid and is held on the cylinder head 22 so as to be able to slide parallel to each valve 16,18.

28.30 is a camshaft arranged horizontally above these valve lifters 25.26. Two cams 32 (32a, 32b) and 34 (34a, 34b) of the same shape are formed on each camshaft 28.30, and the rotation of these camshafts 28.30 causes each cam 32.34 to act as a valve lifter. 25 and 26 are pressed downward at predetermined valve timing to simultaneously open the four intake valves 16 and the three exhaust valves 18. 36 (36A~36D
) and 38 (38A to 38C) are valve springs that bias the intake valve 16 and the exhaust valve 18 in the closing direction, respectively. A cylinder head cover 40 is attached to the cylinder head 22 and covers the valve mechanism such as the camshaft 28, 30 and the valve lifter 25, 26.

Three intake valves 16C and B surrounding the bore center 12 are shown here.
, D is the valve spring 3 of the central intake valve 16B.
6B is located on the outer side of the cylinder than the valve springs 36C and 36D of the intake valves 16C and 16D on both sides. That is, with respect to a plane χ (see FIG. 1) that passes through the bore center 12 and is parallel to the camshaft 28, the upper part of the valve spring 36B is deviated further to the outside of the cylinder than the upper parts of the valve springs 36C and 36D. Similarly, for the three exhaust valves 18A, B, and C surrounding the bore center 12, the upper part of the valve spring 38A of the central exhaust valve 18A is closer to the plane χ than the upper part of the valve springs 38B and C of the exhaust valves 18B and C on both sides. located on the outside of the cylinder.

In this way, the central valve springs 36B and 38A
The upper part of the valve springs 36C, D and 38B, C on both sides of the valve springs 36B, C, D and 38A, B, C are moved closer to each other in the direction of the camshaft 28.30. This allows the engine width in the camshaft 28 and 30 directions to be reduced.

In addition, the centers of the camshafts 28 and 30 are located inside the extension line of the valve shafts of the central valves 16B and 18A (second
), the camshaft 28.30 approaches the engine camshaft 2
The width in the direction orthogonal to 8.30 also becomes smaller.

In this embodiment, the extension line y of the valve shaft of the central exhaust valve 18A is made to intersect with the camshaft 30 (see FIG. 2), so that the couple force exerted on the valve lifter 26 by the exhaust valve 18A is suppressed. It is possible to suppress thrust force from being applied to the valve 18.

In addition, in this embodiment, the valve lifters 25 and 26 combine the intake side and the exhaust side into one, but by deflecting the central valve springs 36B and 38A to the outside of the cylinder as described above, these can naturally be combined into one valve lifter. Valve lifter 2
The lid portions corresponding to the central valves 16B and 18A of 5.26 will also be displaced in the same direction. For this reason, the dimensions of the guide holes of the pulp lifters 25, 26 formed in the cylinder head 22 in the direction of the camshaft 28, 30 are reduced to contribute to reducing the engine width in this direction.

In FIG. 2, reference numeral 42 denotes an exhaust passage, which is formed below the valve mechanism of the exhaust system, and one end of which is connected to the cylinder head 2.
2 on the side of the exhaust valve 18 side, while the other end is 3
It branches into two parts and communicates with each exhaust valve 18.

44 (44a, 44b) are intake passages that pass below the valve mechanism of the intake system and open to the side surface of the cylinder head 22 on the intake valve 16 side. The two intake passages 44 are formed almost symmetrically, and each intake passage 44 further branches into two within the cylinder head 22 and communicates with the intake valves 16B, 16C and 16B, 16D, respectively. 46
(46a, 46b) are connecting pipes communicating with this intake passage 44, 48 is a double carburetor connected to this connecting pipe 46, and 50 (50a, 50b, only 50b is shown) is this carburetor 48. The fuel is mixed into the intake air from this main nozzle 50. Reference numeral 52 denotes a slide-type intake throttle valve, which is located between the joint surface of the connecting pipe 46 and the carburetor 48, and which connects the intake passage 4 in the cylinder head 22.
4 and into the intake passage 54 (54a, 54b) in the carburetor 48. A jet needle (not shown) that moves forward and backward into a needle jet (not shown) in the carburetor 48 is fixed to this throttle valve 52, and as the throttle valve 52 moves forward and backward, the main jet 50
Controls the amount of fuel supplied from the

Reference numeral 56 designates another intake passage independent of the intake passages 44 and 54, and is formed substantially vertically so as to pass between the valve mechanisms of the intake system and the exhaust system. The lower end of this intake passage 56 communicates with the intake valve 16A on the bore center 12, while the upper end thereof passes through the cylinder head cover 40 and opens to the atmosphere.An air funnel 58 is fixed to the upper surface of the six-head cover 40. A sliding intake throttle valve 60 that moves forward and backward into the independent intake passage 56 is held at the joint surface between the air funnel 58 and the head cover 40. This intake throttle valve 60 is connected to the intake throttle valve 52.
At the same time, opening and closing are controlled by a throttle interlocking mechanism 62.

That is, the carburetor 48 holds a shaft 66 that rotates together with the throttle lever 64, and the pivoting ends of levers 68 and 70 fixed to this shaft 66 are connected to links 72 and 74, respectively.
It is connected to the throttle valve 52,60 via. The throttle lever 64 is forcibly rotated counterclockwise and clockwise by a throttle wire (not shown).

Next, the operation of this embodiment will be explained. When the throttle lever 64 is rotated counterclockwise in FIG. 2 by throttle operation, the levers 68 and 70 are also rotated in the same direction together with the shaft 66.
The throttle valve 52 is connected upwardly via the link 72 and to the throttle valve 6.
0 moves to the left via the link 74 and enters the intake passage 54.
56 open in conjunction with each other, so that the amount of intake air flowing through the intake passages 54 and 56 increases. At this time, fuel is supplied to the intake air in the intake passage 54 from the main nozzle 50, and this air-fuel mixture passes through the intake passage 44 to the three intake valves 16B-16D.
It flows into the combustion chamber 24 from there. Further, only air is supplied from the intake passage 56, and this air flows into the combustion chamber 24 from the intake valve 16A. In this way, the intake valve 16A
Since the valve 16A is connected to an independent intake passage 56, a large amount of intake air can be sent from the valve 16A to the combustion chamber 24. In particular, in this embodiment, since the intake passage 56 is provided approximately vertically, its curvature is reduced. This makes it possible to reduce intake resistance and further improve intake efficiency.

In the above embodiments, the present invention is applied to the intake valves 16B, C, and D.
Although the present invention is applied to the exhaust valves 18A, B, and C, the present invention also includes applications applied only to either one of the intake and exhaust valves.

(Effects of the Invention) As described above, the present invention allows the upper part of the valve spring of the central valve to be connected to a plane (including the bore center and parallel to the camshaft) among the three intake/exhaust valves that surround the bore center and are adjacent to each other.
With respect to It becomes possible to make it smaller. Furthermore, since the camshaft is located closer to the bore center than the extension line of the valve shaft of the central valve, the engine width in the direction perpendicular to the camshaft can also be reduced.

[Brief explanation of the drawing]

Fig. 1 is a valve arrangement diagram in one embodiment of the present invention;
The figure is a side view showing the engine and throttle interlocking mechanism taken along the line II-II, FIG. 3 is a perspective view of the intake passage,
FIG. 4 is a perspective view of the valve mechanism. 10... Schilling, 12... Bore center, 16... Intake valve, 18... Exhaust valve, 28.30... Camshaft, 36B, C, D... Valve spring, 38A, B ,
C... Valve spring, χ... Plane. Patent applicant Yamaha Motor Co., Ltd.

Claims (1)

[Claims] In a direct-acting engine in which three intake valves or exhaust valves adjacent to each other surrounding a bore center are opened and closed by a common camshaft, each of the three intake and exhaust valves is coaxially Among the installed valve springs, place the upper part of the valve spring of the center intake/exhaust valve toward the cylinder, with respect to a plane passing through the bore center and parallel to the camshaft, than the upper part of the valve spring of the intake/exhaust valves on both sides. While deflecting outward,
A direct-acting engine characterized in that the center of the camshaft is offset toward the bore center side with respect to the extension line of the valve shaft of the central intake/exhaust valve.