JPH0563606B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a two-stroke V-type internal combustion engine equipped with an exhaust valve whose crankshaft is arranged perpendicular to the direction of vehicle travel.

[Conventional technology]

2 with the crankshaft placed perpendicular to the direction of vehicle travel.
A cycle V-type internal combustion engine is known, for example, as shown in Utility Model Publication No. 1197. In such a V-type internal combustion engine, an exhaust passage extending from each cylinder forming a V-shape is located above the cylinder. The reason is that if they are extended in the same direction, the exhaust pipe that connects to the exhaust passage protruding into the V-shaped space will be obstructed by one of the cylinders, making it difficult to connect. On the other hand, in normal two-stroke internal combustion engines, consideration is often given to prevent the side pressure of the piston during the explosion stroke from being applied to the exhaust port of the cylinder. This is because the cylinder wall on the side where the exhaust port is located lacks pressure receiving area for side pressure, resulting in excessive side pressure.For this reason, when the engine rotation direction is to the right, The exhaust port is installed on the right side of the cylinder.

[Problem to be solved by the invention]

However, as in the conventional example, when the exhaust passages of each cylinder extend in opposite directions when viewed from above the cylinder, for example, when the direction of rotation of the crankshaft is clockwise, side pressure is applied to the exhaust port of one cylinder. Even if you try to prevent this from happening, side pressure will still build up on the exhaust port side in the other cylinder. If the side pressure received on the exhaust port side is within the limit, it is possible to adopt such a configuration, but
In a two-stroke internal combustion engine that allows the exhaust timing to be changed in order to improve output, at high speeds the exhaust port is opened wide and the exhaust timing is advanced, resulting in a lack of side pressure receiving area, which is a significant disadvantage.
There is a problem. The present invention has been made in view of the problems of the prior art, and its purpose is to offset the cylinders in the axial direction of the crankshaft, and to connect the exhaust passages of each cylinder to each cylinder. A 2-cycle V-type exhaust valve with an exhaust valve that is almost perpendicular to the axis of the crankshaft when viewed from above and extends in the same direction to ensure durability and reliability, and to facilitate the connection of the exhaust pipe. The aim is to provide an internal combustion engine.

[Means to solve the problem]

In order to achieve the above object, a two-stroke V-type internal combustion engine equipped with an exhaust valve according to the present invention has a V-type internal combustion engine equipped with an exhaust valve.
The cylinders forming the shape are offset in the axial direction of the crankshaft, and the exhaust passages of each cylinder are made to be substantially orthogonal to the axis of the crankshaft when viewed from above each cylinder and extend in the same direction, so that the exhaust passage of each cylinder is An exhaust valve for changing the exhaust timing is provided at the upper edge of the passage on the exhaust port side, and the exhaust valve of one cylinder is arranged inside the V-shape, and the exhaust valve of the other cylinder is arranged outside the V-shape. The exhaust valve is located in front of the cylinder.

[Effect]

2 with an exhaust valve configured as described above.
Since this is a cycle V-type internal combustion engine, the exhaust passage of each cylinder is made to be substantially orthogonal to the axis of the crankshaft when viewed from above each cylinder, and extend in the same direction, and the upper edge of the exhaust passage of each cylinder on the exhaust port side Since an exhaust valve is provided to change the exhaust timing, side pressure of the piston is less likely to be applied to each exhaust port side during operation of the internal combustion engine. Furthermore, since the front and rear cylinders are offset from each other in the axial direction of the crankshaft, and the exhaust passages extend from the exhaust ports of these cylinders almost orthogonally to the axis of the crankshaft, the exhaust passages do not extend in the same direction. Even if the exhaust pipe is connected to the exhaust passage protruding into the V-shaped space, other cylinders will not get in the way. Furthermore, since the exhaust valve is disposed in front of the cylinder, it is sufficiently cooled by the wind while the vehicle is running.

【Example】

Embodiments of the present invention will be described with reference to the accompanying drawings. In the figure, numerals 1 and 2 are cylinders of a two-stroke V-type internal combustion engine, and these cylinders are arranged facing each other in a V-shape. Pistons 5 and 6 are arranged in cylinder blocks 3 and 4 of the respective cylinders 1 and 2 so as to be movable up and down. In addition, the cylinder blocks 3 and 4 are provided with scavenging passages 7 and 8 that communicate the respective crank chambers and combustion chambers.
, exhaust passages 9 and 10 for discharging combustion gas, and an intake passage (not shown) are formed. Exhaust valves 11 and 12, which are rotating shafts, are rotatably disposed on the inner walls of the exhaust passages 9 and 10. Both end shaft portions 11 of the exhaust valves 11 and 12
a, 12a are bearings 1 in cylinder blocks 3, 4.
3 and 14 so as to be rotatable. Further, as is clear from FIG. 2, the exhaust valves 11 and 12 are generally formed into a chain shape, and a portion of the exhaust valves 11 and 12 exposed into the exhaust passages 9 and 10 is located inside the exhaust passages 9 and 10. The notches 11b and 12b form part of the inner surfaces of the exhaust passages 9 and 10. In FIG. 2, a fixed pulley A is attached to the shaft end 11a of the exhaust valve 11 located on the right side, that is, the front side, and a fixed pulley B is attached to the shaft end 12a of the exhaust valve 12 located on the left side, that is, the rear side. are provided, each connected by a pair of wires 15 and 16, and rotated in conjunction with each other in the same direction. In addition, the drive member 17
is tightened and fixed to the shaft end 11a of the exhaust valve 11 by a tightening bolt 18, and the drive member 1
One end of a pair of drive wires 19 and 20 is engaged with 7, and the other end is connected to a servo motor 21. Since the rotation angle of this servo motor 21 is controlled according to the rotation speed of the engine, the exhaust valve 1 is controlled according to the rotation angle of this servo motor 21.
1 and 12 are rotated in conjunction. As is clear from FIGS. 1 and 2, the axis L of the crankshaft is perpendicular to the direction of travel of the vehicle with respect to the cylinder 1 located forward in the direction of travel of the vehicle. The cylinders 1 and 2 forming a V-shape are offset from each other by an amount of X in the direction of the axis L of the crankshaft. Further, each exhaust passage 9, 1 of each cylinder 1, 2
0 extends in the same direction and is substantially perpendicular to the axis L of the crankshaft when viewed from above each cylinder. Further, the exhaust valve 12 of cylinder 2 is arranged inside the V-shape, and the exhaust valve 11 of cylinder 1 is arranged outside the V-shape. It is arranged. In the configuration of the embodiment as described above, the exhaust passages 9 and 10 of each cylinder 1 and 2 extend in the same direction when viewed from above each cylinder. By selecting the rotation direction (clockwise rotation R in the case of the embodiment), almost no side pressure of the piston is applied to each exhaust port side. Further, since the front and rear cylinders 1 and 2 are offset X from each other in the axial direction of the crankshaft, and the exhaust passages 9 and 10 extend from the exhaust ports of these cylinders almost orthogonally to the axis of the crankshaft, the exhaust passages Even if the cylinders 1 extend in the same direction, the other cylinders 1 do not get in the way when connecting the exhaust pipe to the exhaust passage 10 that projects into the V-shaped space. Furthermore, since the exhaust valves 11 and 12 are disposed in front of the cylinders 1 and 2, they are sufficiently cooled by the wind while the vehicle is running.

【Effect of the invention】

2-cycle V equipped with an exhaust valve according to the invention
In this type of internal combustion engine, the exhaust passage of each cylinder is made to be substantially orthogonal to the axis of the crankshaft when viewed from above each cylinder, and extend in the same direction, and the exhaust timing is set at the upper edge of the exhaust passage of each cylinder on the exhaust port side. Since a changing exhaust valve is provided, the side pressure of the piston is less applied to each exhaust port side during operation of the internal combustion engine, thereby increasing the durability and reliability of a two-stroke V-type internal combustion engine with an exhaust valve. I can do it. Furthermore, since the front and rear cylinders are offset from each other in the axial direction of the crankshaft, and the exhaust passages extend from the exhaust ports of these cylinders almost orthogonally to the axis of the crankshaft, the exhaust passages do not extend in the same direction. Even if the exhaust pipe is connected to the exhaust passage protruding into the V-shaped space, other cylinders do not get in the way, making the connection of the exhaust pipe extremely easy. Furthermore, since the exhaust valve is located at the front of the cylinder, it is sufficiently cooled by the wind while the vehicle is running, which improves the lack of cooling around the exhaust port caused by the provision of the exhaust valve. It is.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a two-stroke internal combustion engine according to the present invention, and FIG. 2 is an enlarged cross-sectional view of essential parts of the two-stroke internal combustion engine according to the present invention. 1, 2... Cylinder, 9, 10... Exhaust passage, 1
1, 12...Exhaust valve, L...Crankshaft axis, X...Offset.

Claims (1)

[Claims] 1 In a two-stroke V-type internal combustion engine equipped with an exhaust valve whose crankshaft is arranged perpendicular to the direction of vehicle travel, the cylinders forming the V shape are offset in the axial direction of the crankshaft, and the exhaust passages of each cylinder are aligned with the cylinders. An exhaust valve for changing the exhaust timing is provided at the upper edge of the exhaust port side of the exhaust passage of each cylinder, the exhaust valve being substantially perpendicular to the axis of the crankshaft and extending in the same direction when viewed from above. A two-cycle engine equipped with an exhaust valve characterized in that the exhaust valve is located inside the V-shape, the exhaust valve of the other cylinder is located outside the V-shape, and each exhaust valve is located at the front side of the cylinder. V-type internal combustion engine.