JPH066928B2 - Fuel supply system for 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 that uses liquefied petroleum gas sealed in a pressure vessel as a fuel.

(Prior Art) Conventionally, in this type of product, fuel is supplied through a carburetor or the like as in a two-cycle engine using gasoline as fuel.

(Problems to be Solved by the Invention) Generally, when the fuel used is gasoline, the proper supply amount of fuel required by the two-cycle engine is determined by the negative pressure in the intake passage of the carburetor and the intake air due to the negative pressure in the crankcase. It is supplied in a metered amount according to the correlation with the diameter of the gasoline discharge hole that opens toward the passage, but in the liquefied petroleum gas sealed in the pressure vessel, the fuel pressurized above atmospheric pressure is Since the fuel is supplied to the intake passage, it is difficult to adjust the fuel by the negative pressure in the intake passage as when the fuel is gasoline. There is also a method to supply by reducing the pressure to be equal to or lower than atmospheric pressure, but due to the property of liquefied petroleum gas, there is a difference in the constituent components but there is a certain temperature requirement, so gas or liquid is required depending on the temperature. Since they are mixed, it is difficult to supply the fuel at the suction negative pressure of the carburetor like gasoline, and the pressure reducing device is large and expensive.

[Structure of the Invention] (Means for Solving the Problems) The present invention provides a fuel flow rate adjusting device 39 in a fuel supply path communicating with a liquefied petroleum gas crankcase, and separates from the fuel supply path 43 by air. An air flow rate adjusting device 75 is provided in the air intake passage 47 provided for supplying the air flow rate, and the diaphragm 63 for operating the flow rate control valve 57 by sensing the positive pressure of the fuel in the fuel flow rate adjusting device 39 is set to the positive pressure. An ammunition 65 for urging in the opposite direction is provided, and the urging force of the ammunition 65 is provided in conjunction with the flow rate adjusting operation of the air flow rate adjusting device 75.

(Operation) When the piston descends and the air intake passage opens with the rotation of the crankshaft, the atmosphere enters the cylinder from the air cleaner through the air intake passage. Fuel enters the carburetor chamber from the gas cylinder and is vaporized.The fuel is sucked into the crankcase when the piston rises while being pressurized to a predetermined pressure through the fuel supply passages such as the pressure adjustment chamber and the metering device. When the piston goes down, it is supplied into the cylinder and sent to the combustion chamber together with air, and when the piston goes up next time, it is compressed and ignites and explodes.
The amount of fuel air changes the urging force in conjunction with the flow rate control operation of the air flow rate adjusting valve by the bullet of the fuel flow rate adjusting valve. For example, when the air flow rate is reduced, the length of the ammunition is increased so that the urging force of the ammunition becomes smaller, and the diaphragm moves by that amount, and the flow control valve becomes smaller by that amount, and the fuel The flow rate becomes smaller.

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 hole 9 communicating with the air cleaner 9 and an intake hole 13 communicating with the air cleaner 11 are opened on the other side. 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 fuel discharge hole 29 at one end of a portable pressure vessel (hereinafter referred to as a gas cylinder) 27 in which liquefied petroleum gas is sealed is supported by a receiving fitting 31 and the other end is a spring holder 33.
Is detachably supported by the pressure regulator 37, the vaporization chamber 3
5, a fuel flow rate adjusting device 39, and an on-off valve 41 to form a fuel supply passage 43 communicating with the cylinder 5. The air suction passage 47 has an air cleaner 11 and one end thereof.
Intake hole 1 that communicates with the
The air flow rate adjusting device 75 communicates with the inside of the crankcase 3 via the air conditioner 3, and the intake hole 11. The fuel flow rate adjusting device 39 and the air flow rate adjusting device 75 are swingably connected by a connecting rod 83. The fuel flow rate adjusting device 39 of FIG. 2 is configured as follows.
The shaft 5 is arranged to open and close the opening 53 inside the gas outlet 51.
A flow control valve 57 and a gas inlet 59, which are driven by the valve 5, are provided in the compartment 61. The swing valve 57 is connected at its free end to a diaphragm 63 mounted so as to partition one side of the compartment 61, and the diaphragm 63 is connected to the diaphragm 63.
Is a compression coil spring-shaped ammunition 65 that acts on the side surface opposite to the flow control valve 57 and urges it in the direction corresponding to the internal pressure.
The flow control valve 57 is thereby pressed in the direction to open the opening 53 of the gas outlet 51. One end of the ammunition 65 is supported by a cylindrical case 67. The case 67 has a screw portion 69 provided on the outer peripheral portion and a screw portion 73 provided on a container 71 that holds the diaphragm 63 and has an opening in the atmosphere. The other end is screwed to project outside the container 71. As shown in FIG. 3, the air flow rate adjusting device 75 has a shaft 79, which is rotatably supported by penetrating the pipe line 77 and has a tapered shape, one end of which projects from the main body 80 and the other end of which is an oil seal 87 and a spring. 89 and a holding metal fitting 91 have a closed structure, and a hole portion 81 communicating with the pipe 77 is provided.

In the above-described embodiment, the liquefied petroleum gas in the gas cylinder 3 is supplied under pressure from the gas inlet 59 into the compartment 61, so that the diaphragm 63 is blasted as the pressure in the compartment 61 increases. The flow rate control valve 57 is swung in the direction of closing the opening 53 of the gas outlet 51 by moving against the action of 65 to reduce the inflow of fuel. The flow control valve 57 opens and closes the gas outlet 51 to adjust the amount of fuel supplied to the engine. The operation of the flow control valve 57 can be controlled by moving the diaphragm 63 in response to the urging force of the ammunition 65 and the position of the diaphragm 63 corresponding to a predetermined constant pressure in the compartment 61. The pressing force of the bullet 65 can be easily adjusted by moving the screw 67 of the case 67 in the axial direction to change the total length.

Further, by separately providing the fuel supply passage 43 and the air intake passage 47, the influence of the negative pressure of the intake passage is removed, and the fuel is not discharged unnecessarily into the air inflow passage 47 during the engine backflow phenomenon. By interlocking the operation of the air flow rate adjusting device 75 for adjusting the intake air amount and the fuel flow rate adjusting device 39, it is possible to precisely adjust and supply the required amount of fuel according to the intake air amount. is there.

Note that FIG. 4 shows another embodiment, in which the pressing force of the coil spring 67 is adjusted by moving the case 67 up and down via the rotating cam 85.

[Advantages of the Invention] According to the present invention, (1) the amounts of fuel and air can be easily adjusted simultaneously, and therefore the output of the engine can be easily controlled. (2) It is not necessary to reduce the fuel pressure to atmospheric pressure. (3) Since the fuel is supplied in a state of being pressurized to a predetermined pressure, the influence of the flow rate due to the change in the negative pressure in the crankcase is small, and an appropriate mixing ratio can be set.

[Brief description of drawings]

FIG. 1 is a side sectional view of an embodiment of the present invention, FIGS. 2 and 3 are side sectional views of essential parts, and FIG. 4 is a side sectional view of another embodiment. DESCRIPTION OF SYMBOLS 1 ... Engine 3 ... Crankcase 27 ... Pressure container (gas cylinder) 39 ... Fuel flow rate control device 43 ... Fuel supply path 47 ... Air suction part 57 ... Flow control valve 63 ... Diaphragm 65 ... Ammunition 75 ... Air flow rate control device

Claims (1)

[Claims] 1. A fuel flow rate adjusting device 39 is provided in a fuel supply passage 43 provided so as to connect the inside of a crankcase 3 of an engine 1 and a pressure container 27 in which liquefied petroleum gas is sealed, and the fuel supply passage 43 is provided. Separately from the above, an air flow rate adjusting device 75 is provided in the air intake passage 47 provided for supplying air, and a diaphragm 63 for operating the flow rate control valve 57 by detecting the positive pressure of the fuel in the fuel flow rate adjusting device 39. Is provided with an ammunition 65 for urging the
A fuel supply device for a two-cycle engine, wherein the urging force of the ammunition 65 is provided in association with a flow rate adjusting operation of the air flow rate adjusting device 75.