JPS58170823A - Fuel supplying device for starter of two cycle engine - Google Patents

Abstract

PURPOSE:To flow rich fuel mixture for the low-temperature starting time of the engine, which is different from the suction air of a main path, and prevent scuffing of a piston by a method wherein a starter suction air path, branched from the main path of a carburettor, is connected to the scavenging path of a cylinder through a one-way valve. CONSTITUTION:When an engine is started under low temperature by lifting a plunger valve 7 up and opening the starter suction air path 6, the suction air of the main path 4 is sucked into a crank chamber through a suction part 2 in accordance with the opening and closing of the piston 5 and is introduced into a combustion chamber at the upper part of the cylinder 1 through the scavenging path 10 by the compression of the crank chamber. The rich fuel mixture in the starter suction air path 6 is introduced into the scavenging path 10 through the one-way valve 9 when the pressure in the crank chamber is negative. Then, the rich fuel mixture is introduced into the combustion chamber at the upper part of the cylinder 1 together with the suction air of the main path 4. The rich fuel mixture in the starter suction air path 6, which is assisting the starting of the engine, is sent into the scavenging path 10, therefore, it will never wash the wall surface of the piston 5 opening and closing the suction air path 2.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a starter fuel supply system for a λ cycle engine that is improved to prevent piston scuffing.

Modern cocycle engines use a pump linked to the engine to supply lubricating oil in small amounts to the crank chamber, etc.
The rotation of the crank wheel creates agitation that lubricates the cylinder and piston walls.

When the engine is stopped, the lubricating oil on the piston wall flows down into the crank chamber at the bottom.

When starting the engine at low temperatures, the starter intake passage, which bypasses the carburetor, is opened and rich fuel is mixed with the intake air in the main passage to aid in starting.

In the type that uses a piston to open and close the outlet of the intake passage, this rich fuel washes the piston wall.

There is less lubricating oil on the piston wall, which has less adhesion during startup. In addition, immediately after startup, the piston heats up faster than the cylinder, so the gap between the cylinder and piston becomes smaller.

This causes scratches on the piston wall, especially on the side of the intake hole that is washed with fuel.

This is called scuffing, and it causes burn-in and is inconvenient.

This invention is an improvement to prevent such scuffing from occurring, and embodiments of the invention shown in the drawings will be described below.

Connect the main passage of the carburetor 3 to the tip of the cylinder/KIR girder intake hole of the cocycle engine.

The intake hole is a piston j that slides back and forth inside the cylinder l.
It is opened and closed by K. The carburetor 3 is provided with a starter intake passage 6 branching off from the main passage, and when starting at a low temperature, the plunger valve 7 is pulled up and opened to supply rich fuel. The starter intake passage 6 is connected to the scavenging passage 10K of the cylinder l via a one-way valve D through a pipe j.

The effect will be explained.

When starting the engine by pulling up the plunger valve and opening the starter intake passage 1 at low temperatures, the intake air from the main passage passes through the intake hole and is drawn into the crank chamber as the piston 3 opens and closes. Compressed air from the crank chamber passes through the scavenging passage 10 and enters the combustion chamber in the upper part of the cylinder l. On the other hand, the rich fuel in the starter intake passage 6 is a one-way valve when the crank chamber is under negative pressure! It enters the scavenging passage IO via the. Then, together with the intake air from the main passage, it enters the combustion chamber in the upper part of cylinder l.

In this way, the rich fuel in the starter intake passage 6, which helps with starting, is sent to the scavenging passage IO, so the piston opens and closes the intake passage! There is no need to wash the wall surface of the piston j, and it is possible to prevent the amount of lubricating oil adhering to the wall surface of the piston j from decreasing. Accordingly, scuffing of the piston can be prevented.

As explained above, in this invention, the starter intake passage branched from the main passage of the carburetor is connected to the scavenging passage of the cylinder via a one-way valve, so that the starter intake passage is opened during cold start and rich fuel is supplied. When feeding, rich fuel flows into the scavenging passage separately from the intake air in the main passage. Therefore, the piston wall is not washed with rich fuel, the amount of lubricating oil adhering to the piston wall is prevented from being reduced, and scuffing of the piston can be prevented.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a survey map, and FIG. 1 is a sectional view taken along the line A--A in FIG. l...Cylinder, 3...Carburizer, G...Main passage, 1...Starter intake passage, 9...One-way valve, IO・
...Scavenging passage. Applicant's agent Kiyoshi Inomata

Claims (1)

[Claims] A starter fuel supply device for a co-cycle engine in which a starter intake passage branched from the main passage of a carburetor is connected to a scavenging passage of a cylinder via a one-way valve.