JPH066195Y2 - Two-cycle engine pool fuel return system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a residual fuel returning device for a two-cycle engine mounted on, for example, a brush cutter.

(Prior Art) A conventional example of the two-cycle engine will be described with reference to FIG. 3, in which a cylinder (2) is arranged on a crankcase (1),
The bearing (3a) supports the crank shaft (3) on the crank case (1), and the crank wave (4) is attached to the inner end side of the crank shaft (3).
The connecting rod (5) is connected in series to connect the end of the connecting rod (5) to the piston (6) in the cylinder (2), and the air cleaner (1a) on the side of the crankcase (1). 8), the intake passage (10) for supplying the fuel mixture through the carburetor (9), the reed valve (11), the scavenging passage (12) in the lower part of the cylinder (2), the spark plug (13), a cooling fan (14), a muffler (15), a fuel tank (16), etc. are arranged, and the fuel mixture of air and fuel generated by the carburetor (9) is introduced into the intake passage (10). From the reed valve (11) into the crankcase (1) for combustion, and a part of the fuel mixture becomes liquid in the crankcase and becomes fuel at the bottom of the crankcase. Has become.

(Problems to be Solved by the Invention) In the conventional two-cycle engine, when the clutch is tilted to the left side in the drawing so that the clutch is on the lower side, the accumulated fuel at the bottom of the crankcase is sequentially sprung up by the crank wave and reduced. However, when the carburetor side is tilted to the right side in the drawing so as to be downward, the accumulated fuel accumulates in the lower part of the reed valve and a large amount is accumulated. A large amount of the accumulated fuel in the lower part flows into the crank wave side and is temporarily jumped up in a large amount by the same crank wave, so the fuel-air mixture supplied to the combustion chamber through the scavenging passage suddenly becomes rich, and rotation modulation is performed. There is a problem that the engine will start up and stop.

The present invention was developed in order to address the above-mentioned problems, and it automatically returns the accumulated fuel at the bottom of the reed valve at the bottom of the crankcase to the intake passage side, thereby making the accumulated fuel effective. SUMMARY OF THE INVENTION It is an object of the present invention to provide a stagnation fuel return device for a two-cycle engine, which has a substantially reduced amount and improved operational reliability of the engine.

(Means for Solving the Problems) The present invention is a two-cycle system in which a carburetor is attached to a side portion of a crankcase through an insulator, and a fuel mixture is supplied from a suction passage of the insulator into a crankcase through a reed valve. In the engine, a communication passage is provided between the lower portion of the reed valve in the crankcase and the suction passage, and a communication passage is provided for returning accumulated fuel in the lower portion of the reed valve to the suction passage, and the communication passage is recessed in an inner surface of the insulator. The present invention is characterized in that it is formed by a groove and a seat portion of the reed valve that covers the opening side of the groove. Even if the engine is tilted toward the carburetor side, the accumulated fuel under the reed valve passes through the communication passage and the intake passage. The fuel is automatically reduced and the formation of the communication passage is facilitated.

(Operation) The fuel mixture is sucked and supplied from the intake passage into the crankcase through the reed valve, the engine is operated, and part of the fuel mixture supplied into the crankcase becomes liquid and is generated at the bottom of the crankcase. The accumulated fuel is returned from the lower part of the reed valve to the intake passage, is returned to the intake passage, is mixed with new fuel mixture, and is sucked and supplied into the crankcase, so that the accumulated fuel at the bottom of the crankcase is effective and automatically. Reduced,
The front part return of the accumulated fuel by the communication passage, the inclination of the engine,
And it becomes smooth by the differential pressure between the crankcase and the suction passage.

(Embodiment) One embodiment of the present invention is shown in FIG. 1 and FIG.
(1) is the engine body, that is, the crankcase, (1a) is the insulator on the side of the crankcase (1), (3) is the crankshaft, and (4) is connected to the inner end side of the crankshaft (3). Crank wave, (5) connecting rod connected between crank wave (4) and piston (not shown), (8) air cleaner, (9) vaporizer, (10) inside insulator (1a) The suction passage (11) is a reed valve provided on the inner end side of the suction passage (10).
In a two-cycle engine that supplies a fuel-air mixture into the crankcase (1) through a crankcase (1), the reed valve lower part (11c) in the crankcase (1) and the reed valve lower part
The accumulated fuel returning device (11c) is a accumulated fuel returning device for a two-cycle engine in which a communication passage (15) for returning the accumulated fuel to the intake passage (10) is connected to the reed valve seat portion.

The reed valve (11) has a tightening screw on the inner end side of the suction passage (10).
The valve body (11a) and the valve retainer (11b) attached by (12), and the communication passage (15) is a V-shaped, U-shaped or semi-circular shape recessed in the inner surface of the insulator (1a). It consists of a groove with a cross section and is located behind the seat of the reed valve (11) in the crankcase.
It is vertically installed so as to communicate with the suction passageway (10) from the bottom surface of (1).

When the engine is operating, the fuel mixture generated by the air cleaner (8) and the carburetor (9) is sucked and supplied from the intake passage (10) into the crankcase (1) through the reed valve (11). To a combustion chamber (not shown).

A part of the fuel-air mixture that has flowed into the crankcase (1) becomes liquid and accumulates at the bottom of the crankcase (1), and the accumulated fuel at the bottom of the crankcase (4) appears when the engine is tilted to the left in the figure. When the engine is tilted to the right side (the carburetor (9) side) in the figure, it accumulates in the lower part of the reed valve, but the accumulated fuel in the lower part of the reed valve increases. 1) Inside and suction passage (1
Due to the pressure difference in (0), engine inclination, etc., the communication path (1
5) It positively flows out into the intake passageway (10), and the accumulated fuel is automatically and extremely effectively reduced and almost disappeared, and rotation modulation due to the accumulated fuel is prevented and smooth operation is achieved. Become.

The accumulated fuel is mixed and vaporized in a new fuel mixture in the intake passage (10) and used for combustion.

(Effect of the Invention) As described above, according to the present invention, the crankcase is provided between the lower portion of the reed valve in the crankcase and the suction passage, and the communication passage for returning the fuel accumulated in the lower portion of the reed valve to the suction passage is provided. The fuel accumulated at the bottom is skipped by the crank wave or returned to the suction passage through the communication passage and vaporized again, and the fuel accumulated at the bottom of the crankcase is automatically and effectively reduced and almost disappeared. Rotational modulation and engine stall of the engine are prevented, smooth operation is achieved, and the operational reliability is significantly improved along with effective use of fuel, and the communication passage has a groove recessed in the inner surface of the insulator forming the intake passage. Since the groove is formed by the seating portion of the reed valve that covers the open side of the groove, the groove can be shaped and sized freely by injection molding or the like, which may affect engine performance. It has the effect that it can be easily molded without blurring.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of an essential part showing an embodiment of the present invention, FIG. 2 is a front view of the reed valve portion of FIG. 1, and FIG.
It is a longitudinal cross-sectional view of a cycle engine. 1: Crank case, 10: Suction passage, 11: Reed valve, 11c: Lower portion of reed valve, 15: Communication passage

Claims (1)

[Scope of utility model registration request] 1. A two-cycle engine in which a carburetor is attached to a side portion of a crankcase via an insulator, and a fuel mixture is supplied from a suction passage of the insulator into the crankcase via a reed valve. Between the lower portion of the reed valve and the suction passage, a communication passage for returning the accumulated fuel in the lower portion of the reed valve to the suction passage is provided, and the communication passage has a groove recessed in the inner surface of the insulator and the opening of the groove. And a seat portion of the reed valve that covers the side of the reed valve.