JPS5939925A - Scavenging system for 2-cycle engine - Google Patents

Abstract

PURPOSE:To reduce contact of a ring thus to reduce noise and to open/close the scavenging hole instantaneously, by making the upper and lower edges of the open edge of a scavenging hole rhomboidal while inclining high rearward and inclining high rearward the piston top face in accordance to the inclination of the upper and lower edges. CONSTITUTION:When a piston 4 moves downward, the piston ring 5 will expand outward at the portion of a scavenging hole 3 while when passing the low edge corner of said hole 3, it is pushed to the inside to collide against the corner. Since the low edge is inclined 8, it is pushed gradually from the rear side to the front side to prevent noise. While when moving upward, the piston ring 5 is gradually pushed due to said inclination, thus to prevent noise.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a scavenging device for a cocycle engine that aims to reduce noise generated by piston rings.

A cocycle engine has exhaust holes on the front of the cylinder wall, and scavenging holes on the left and right sides. In some cases, small scavenging holes may also be opened on the rear surface. Usually, the open ends of the scavenging holes on the left and right sides are rectangular in shape and are opened and closed by the reciprocation of the piston.

When the piston ring passes over the upper and lower edges of the open end of the scavenging hole,
The scavenging hole hits the piston ring as it expands outwards, causing ring noise. If the upper edge is made into a chevron shape, the contact of the ring will be reduced and the sound can be reduced, but the opening area of the scavenging hole will be smaller and the output will be reduced accordingly.

This invention is an improvement that can prevent the piston ring from hitting the upper and lower edges of the open end of the scavenging hole and generating noise.Hereinafter, embodiments of the invention will be described as shown in the drawings.

An exhaust hole λ is opened in the front face of the cylinder wall l, and scavenging holes 3 are opened in the left and right sides. A piston is slidably inserted into the inner side 1 of the cylinder wall surface l and reciprocates, and the exhaust hole and the scavenging hole 3 are opened and closed by the reciprocation of the piston t. A circumferential groove is provided at the upper part of the outer periphery of the piston, into which a shaped piston ring j is inserted so as to expand outward and press against the cylinder wall surface l. 6 is a cylinder head, and 7 is a spark plug. However, the present invention
Is the upper and lower edge of the opening end of the scavenging hole 3 to the cylinder wall l inclined highly toward the rear? to make a parallelogram. Also, the top surface of the piston is tilted high toward the rear in line with the slope ♂.

The effect will be explained.

The piston moves back and forth on the cylinder wall.

When moving from top to bottom, the piston ring j expands outward at the scavenging hole 3, and when it passes the corner of the lower edge of the scavenging hole 3, it is pushed inward so as to collide with the corner. However, since the lower edge is inclined g+♂, it is pushed into contact gradually from the rear side toward the front side, and no collision noise is generated. Similarly, when moving from the bottom to the top, the piston ring j is gradually pushed in by the slope r of the upper edge of the scavenging hole 3, so that no collision noise is generated. In this way, noise generated when the piston ring hits the corners of the upper and lower edges of the scavenging hole can be prevented. Incidentally, even if the upper and lower edges of the scavenging hole 3 are inclined, since the top surface of the piston hole is inclined, the upper edges can be opened and closed at the same time. Further, the slope of the top surface of the piston hole also helps to collect combustion gas near the ignition plug 7.

As explained above, the present invention provides a cosaicle engine in which the exhaust hole is fully opened at the front of the cylinder wall and the scavenging holes are opened at the left and right side surfaces, in which the upper and lower edges of the opening end of the scavenging hole are tilted high toward the rear. In addition to making it into a parallelogram shape, the top surface of the piston (which is highly inclined toward the rear in accordance with the slope of the upper and lower edges) is designed to reduce the force on one side of the air hole when the piston ring passes through the upper and lower edges. ) It is possible to prevent the generation of a ringing sound due to a collision by not being pushed in by the first contact. Further, since the top surface of the piston is inclined in accordance with the slope of the upper and lower edges of the scavenging hole, the scavenging hole can be opened and closed instantaneously. The slope of the top surface of the piston also helps in assembling the combustion gas near the ignition plug, which improves ignition performance.

In addition, the opening end of the scavenging hole is also highly inclined toward the rear side 1, so
Scavenging air can be blown toward the rear of the cylinder head, improving scavenging efficiency and increasing output.

[Brief explanation of the drawing]

The figure is a longitudinal side view showing one embodiment of the present invention.
・Cylinder wall surface, ko...exhaust hole, 3...scavenging hole, hiro...piston, r...tilt, ri...tilt.

Claims (1)

[Claims] In a co-cycle engine that has an exhaust hole in the front of the cylinder wall and scavenge holes in the left and right sides, the upper and lower edges of the scavenge hole opening end are shaped like parallelograms with a high slope toward the rear, and the piston A scavenging device for a λ cycle engine, characterized in that the top surface of the laminate is tilted high toward the rear in accordance with the slope of the upper and lower edges.