JPH0635857B2 - 2-cycle engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a two-cycle engine which uses liquefied petroleum gas sealed in a pressure vessel as a fuel.

(Prior Art) Conventionally, in this type of product, as in a two-cycle engine that uses gasoline as a fuel, fuel is supplied by being mixed with intake air via a carburetor of the engine. That is, the intake port that opens from the carburetor to the side wall of the cylinder through the intake passage is closed when the piston descends, and opens when the piston rises to communicate with the inside of the crankcase.

Due to the structure of the two-cycle engine, there is a phenomenon in which fuel is blown back into the atmosphere due to the pressure difference between the crankcase internal pressure and the atmospheric pressure until the intake port is completely closed during the piston lowering process. As in the case of gasoline, when liquefied petroleum gas is mixed with intake air, the liquefied petroleum gas supplied to the fuel supply passage flows into the carburetor even after closing the intake port that does not need to be supplied, and momentarily remains in the intake passage. It is dissipated into the atmosphere wastefully by being diffused into the atmosphere from the air intake hole opening to the atmosphere by the accumulated blowback wind. There is also a method of reducing the pressure to be equal to or less than the atmospheric pressure and supplying it,
Due to the nature of liquefied petroleum gas, there are differences in the constituent components for complete vaporization, but a certain temperature is required, and depending on the temperature, gas,
Since liquid is mixed in, it is difficult to supply fuel at a suction negative pressure similar to gasoline, and the decompression device is large and expensive.

For this reason, conventionally, there has been one in which a fuel supply passage for vaporizing and supplying the liquefied petroleum gas to be supplied to the engine and an air intake passage are separately provided separately and opened in the side wall of the cylinder. The fuel supply passage is configured to be closed at the piston's raised position and open at the lowered position to communicate with the combustion chamber, and the air intake passage is closed at the piston's lowered position and opened at the raised position to open the crankcase. To communicate with
The air in the crankcase was configured to be sent to the combustion chamber from the scavenging passage when the piston descends.

(Problem to be Solved by the Invention) In the conventional configuration, the fuel supply passage is opened at the lower position of the piston to supply the fuel to the combustion chamber. Therefore, at the same time, mixing with air sent from the crankcase through the scavenging passage is performed. It became non-uniform and caused the engine to malfunction.

(Means for Solving the Problem) In the present invention, a fuel supply passage and an air intake passage are separately provided separately, and an opening for opening the fuel supply passage to the cylinder side wall and an air intake passage to the cylinder side wall are provided. The intake port is closed by the piston at the lowered position of the piston, opened at the raised position, and communicated with the inside of the crankcase.

(Function) When the piston rises as the crankshaft rotates, the fuel enters the carburetor chamber from the gas cylinder and is vaporized.
The air is sucked into the crankcase through a fuel supply passage such as a pressure regulator and a metering device, and then an air suction passage is opened, and the atmosphere enters the crankcase from the air cleaner through the air suction passage. When the piston descends, the fuel mixed in the air in the crankcase enters the combustion chamber through the scavenging passage, and when the piston rises, it is compressed and ignites and explodes. Therefore,
Even if a blowback wind is generated in the air intake passage, the fuel supply passage is separately provided, so that it is not wastefully discharged to the atmosphere together with the blowback wind.

Further, since the fuel supply passage communicates with the crankcase, the fuel is agitated in the crankcase, uniformly mixed with air, and sent to the combustion chamber.

Embodiment An embodiment of the present invention will be described in detail below with reference to the drawings.

In FIG. 1, a cylinder 5 is fixed above the crankcase 3 of the engine 1, and a muffler 7 is attached to one side of the cylinder 5.
An exhaust port 9 communicating with the air cleaner 11 and an intake port 13 communicating with the air cleaner 11 are opened on the other side. In addition, the intake port 13,
A scavenging port 14 at an upper end of a scavenging passage 12 having a lower end communicating with the crankcase 3 is opened on a side wall in a direction orthogonal to the exhaust port 9. A crankshaft 15 is pivotally supported by the crankcase 3, one end of a connecting rod 19 is connected to a crank arm 17 provided on the crankshaft 15 via a crank pin 21, and the other end of the connecting rod 19 is inside the cylinder 5. It is connected via a slidable piston 23 and a piston pin 25. A portable pressure vessel (hereinafter referred to as a gas cylinder) 27 filled with liquefied petroleum gas is supported at a fuel discharge hole 29 at one end by a metal fitting 31 and at the other end by a spring holder 33 so as to be detachably supported. A fuel supply passage 43 that communicates with the cylinder 5 through the pressure regulator 35, the pressure regulator 37, the metering device 39, and the like is configured. The opening portion 45 provided on the side wall surface of the cylinder where the fuel supply passage 43 opens is configured to open and close by the operation of the piston 23. The air suction passage 47 is connected to the air cleaner 1
1, an intake pipe 49 having one end communicating with the air cleaner 11 and the other end communicating with the intake hole 13 on the cylinder wall surface, and the intake hole 1
3 and 3. The intake port 13 and the opening 45 are closed by the piston 23 when the piston 23 descends, and open when the piston 23 rises. Further, the scavenging port 14 and the exhaust port 9 are provided so as to be closed when the piston 23 rises and open when the piston 23 descends.

In the above embodiment, the fuel discharged from the gas cylinder 27 is supplied to the fuel supply passage 43 through the socket fitting 31, but the piston side wall is opened 45 in the cylinder wall surface by the upward movement of the piston 23 which is interlocked with the movement of the crankshaft 15.
To open the fuel supply passage 43 to the crankcase 3 and to open the intake port 13 of the air intake passage 47 to communicate with the crankcase 3, so that when the piston 23 descends, air is introduced into the crankcase 3. The mixed fuel is sent to the combustion chamber through the scavenging passage 12, and then compressed, ignited and exploded when the piston 23 rises. It is possible to supply fuel to the engine at the timing of intake and exhaust, and since the circuit is separate from the air intake passage 47, there is no direct discharge of liquefied petroleum gas to the air intake passage 47, Therefore, the liquefied petroleum gas can be economically supplied without wasting the fuel into the atmosphere due to the blowback wind, and the fuel is uniformly mixed with the air in the crankcase 3 and sent from the scavenging passage 12 to the combustion chamber. It is a thing.

The pressure adjuster 37 of the present invention can also have the function of the adjuster 39. Further, even if the fuel supply passage 43 and the air suction passage 47 are arranged side by side in the same container, or if each is provided in a dedicated container, the effect does not change.

EFFECTS OF THE INVENTION According to the present invention, wasteful fuel is not released to the atmosphere due to blowback wind of the air suction passage, and the supply of liquefied petroleum gas to the engine can be easily and economically controlled, and the fuel can be controlled. Is uniformly mixed with air to prevent engine malfunction.

[Brief description of drawings]

 FIG. 1 is a side sectional view of an embodiment of the present invention. 3 ... Crankcase, 5 ... Cylinder 12 ... Scavenging passage, 13 ... Intake port 23 ... Piston, 43 ... Fuel supply passage 45 ... Opening 47 ... Air suction passage

Claims (1)

[Claims] 1. A fuel supply passage 43 for vaporizing liquefied petroleum gas to supply it to a cylinder 5 of an engine 1 and an air intake passage 47 for supplying air are separately provided.
A scavenging passage 12 that connects the crankcase 3 and the combustion fuel chamber is provided at a lower position of the piston 23 that slides in the cylinder 5, and an opening 45 that opens the fuel supply passage 43 to a side wall of the cylinder 5 and the air The intake passage 13 and the intake port 13 opening to the side wall of the cylinder 5 are closed by the piston 23 at the lowered position of the piston 23, opened at the raised position and communicated with the inside of the crankcase 3. Two-cycle engine.