JPH04103864A - Fuel supply device for internal combustion engine - Google Patents

Abstract

PURPOSE:To secure the sufficient quantity of gasificated fuel as well as to make an arrangement compact by supplying fuel in a liquefied gas container in a state of liquid to a mixing chamber via a primary pressure regulator, and thereby permitting a pipe connecting the liquefied gas container to the primary pressure regulator to go around the heating section of an engine. CONSTITUTION:When an engine 7 is started with a cock 17 opened, liquid fuel at the bottom section of a liquefied gas container 27 is sucked in through a fuel suction pipe 25, a check valve 20, a valve opening mechanism 23, the cock 17, a pipe 18, a heater 19 and a pipe 20 so as to be gasificated by outside temperature. Gasificated fuel in the primary pressure regulator 32 is sucked in a venture 7 through a passage 4a, it is subsequently sucked in a cylinder 9 together with air from an air purifier 2 via an intake air port 6, it is then burned within the cylinder 9, so that a piston 10 is thereby reciprocated while exhaust gas is exhausted out of an exhaust port 13 to a muffler 15. When the engine 7 is started, the heater 19 is heated by exhaust temperature, liquefied fuel flowing from the liquefied gas container 27 to the primary pressure regulator 32 is thereby gasificated by the heater 19 so as to be stored in the primary pressure regulator 32, so that it is sucked in the cylinder 9 as required by the engine.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a fuel supply system for an internal combustion engine that uses liquefied petroleum gas (such as butane) as fuel.

[Prior Art] Conventionally, when using fuel in a liquefied gas container (cylinder) used in an ordinary portable gas stove as fuel for an internal combustion engine, the liquefied gas container is supported horizontally or vertically on the engine, and the fuel is liquefied. It is vaporized inside a gas container and supplied to the engine. The fuel in the liquefied gas container is kept in a liquid state so that it does not eject, and the amount of vaporized fuel that is ejected from the liquefied gas container remains almost constant. When the fuel is cooled by the heat of vaporization and the temperature inside the liquefied gas container drops to 0° C., the amount of vaporized fuel decreases significantly, making it impossible to continue operating the engine. Increase the amount of vaporized fuel. Although there are methods such as installing multiple liquefied gas containers, the use of liquefied gas containers is
There are restrictions depending on conditions such as engine output and ambient temperature.

[Problems to be Solved by the Invention] In view of the above-mentioned problems, an object of the present invention is to provide a fuel supply device for an internal combustion engine that can supply a necessary amount of vaporized fuel to the engine from a general liquefied gas container. be.

Means for Solving Problem E] In order to achieve the above object, the structure of the present invention is such that the fuel suction pipe is always protruded below the liquid level of the liquefied gas container, and the fuel in the liquefied gas container remains in liquid form during engine operation. The gas is supplied to the mixer via the primary pressure regulator, and the pipe connecting the liquefied gas container and the primary pressure regulator is bypassed to the heat generating part of the engine.

[Function] Fuel is drawn from the liquefied gas container in a liquid state to the primary pressure regulator, and is vaporized in the heat generating part of the engine in the primary pressure regulator or in the piping leading to the primary pressure regulator, so it will not change depending on the operating conditions of the engine. The required amount of vaporized fuel can be supplied to the engine.

[Embodiments of the Invention] FIG. 1 is a side sectional view of an internal combustion engine equipped with a fuel supply device according to the present invention. As is known, the cylinder 9 of the two-stroke internal combustion engine 7 is closed at its upper end by a head that supports a spark plug 8 and is connected at its lower end to a crankcase 37 that supports a crankshaft 35 . A piston 10 fitted in the cylinder 9 is connected to one end of a connecting rod 38 by a pin 34.

The other end of the connecting rod 38 is connected to the arm of the crankshaft 35 by a pin 36. Suction port 6 provided on the wall of cylinder 9
are connected to the air purifier 2 with the mixer 3 in between. The mixer 3 includes a primary pressure regulator 32, a venturi 4, and a throttle valve 5, and draws vaporized fuel from the primary pressure regulator 32 to the venturi 4 through a passage 4a. Exhaust port 1 on cylinder wall
3 is coupled with a muffler 15.

The fuel supply system for an internal combustion engine according to the invention is preferably configured to support a generally cylindrical liquefied gas container 27 on a frame 26 connected to the bottom of the engine. For this purpose, a valve opening mechanism 23 is provided on the vertical wall 21 at one end of the horizontal underframe 26. The liquefied gas container 27 has a check valve 22 and a fuel suction pipe 25 attached to the inner wall of the base 24, which is made of a flat circular plate with an end wall, and the inner end of the fuel suction pipe 25 is bent downward to form the liquefied gas container. It is projected to the bottom of 27.

To position the liquefied gas container 27 on the underframe 26 in the illustrated state, insert the valve opening mechanism 23 into the notch provided on the periphery of the base 24.
The protruding piece 23a protruding from is engaged.

When the cap 24 is pressed against the valve opening mechanism 23, the check valve 22 is opened, and the bottom of the liquefied gas container 27 is communicated with the pipe 18 via the fuel suction pipe 25, the valve opening mechanism 23, and the cock 17.

A muffler 15 is used to vaporize the liquid fuel in the heat generating part of the engine.
A heater 19 made of a tube meandering along the wall surface or spirally curved is disposed on the outer wall of the cover 14 covering the heater. The heater 19 is connected via a tube 20 to the 1 disposed at the bottom of the mixer 3.
It is communicated with the next pressure regulator 32.

An oil tank 33 is disposed on the wall of the engine, and lubricating oil from the oil tank 33 is supplied to the venturi 4 through a pipe 31.

However, since the oil supply mechanism is not related to the gist of the present invention, a description thereof will be omitted.

Next, two steps are taken to operate the fuel supply system for an internal combustion engine according to the present invention.
I will explain. When the cock 17 is opened and the engine 7 is started, the liquid fuel at the bottom of the liquefied gas container 27 flows into the fuel suction pipe 25.
, the check valve 22, the valve opening mechanism 23, the cock 17, the pipe 18, the heater 19, and the pipe 20, and are sucked into the primary pressure regulator 32.
It is vaporized by outside heat. The vaporized fuel in the primary pressure regulator 32 is drawn into the venturi 7 through the passage 4a, and is drawn into the cylinder 9 together with the air from the air cleaner 2 through the intake port 6. The vaporized fuel is burned inside the cylinder 9, moves the piston 10 forward, and is discharged from the exhaust port 13 to the muffler 15.

When the engine 7 starts, the heater 19 is heated by the exhaust heat, so the liquid fuel flowing to the liquefied gas container 27 or the primary pressure regulator 32 is vaporized by the heater 19 and transferred to the primary pressure regulator 32.
and is sucked into the cylinder 9 according to the amount required by the engine.

In the embodiment shown in FIG. 2, a second heater 19a is disposed on a cover 39 disposed on the cylinder wall, one end of the heater 19a is communicated with the heater 19 through a pipe 20, and the second heater 19a is connected to the heater 19 through a pipe 20. The other end is connected to a primary pressure regulator 32a disposed above the mixer 3, and vaporized fuel is supplied from the primary pressure regulator 32a to the venturi 4 via a passage 4b. According to this embodiment, the vaporization of the liquid fuel is further promoted and operation in cold regions becomes possible.

In each of the above embodiments, the liquefied gas container 27 is placed horizontally. However, the present invention is not limited to this, and the liquefied gas container 27 may be placed vertically. connects the fuel inlet 25 to the liquefied gas container 27
If attached to the upper end wall and extending the inner end of the fuel suction pipe 25 straight toward the inner surface of the lower end wall, the liquefied gas container 2
Fuel No. 7 is sucked into the primary pressure regulator in a liquid state, and is heated and vaporized by the heat generating part of the engine on the way.

[Effects of the Invention] As described above, in the present invention, the fuel suction pipe is always protruded below the liquid level of the liquefied gas container, and while the engine is operating, the fuel in the liquefied gas container is liquid and flows through the primary pressure regulator to the mixer. The liquefied gas is supplied to the pipe that connects the liquefied gas container and the primary pressure regulator, or is bypassed to the heat generating part of the engine. Therefore, when the fuel is in a liquid state from the liquefied gas container,
Since the fuel is vaporized by the heat of the engine while being sucked into the next pressure regulator, the amount of vaporized fuel required for the operating conditions can be supplied to the engine.

Since the fuel is not vaporized inside the liquefied gas container, there is no problem that the liquefied gas container cools down during operation and vaporized fuel is no longer supplied.

Simply place the primary pressure regulator and fuel in the heat generating part of the engine.
Since a sufficient amount of vaporized fuel can be obtained and there are no particular restrictions on the attachment part to the engine, a compact arrangement is possible.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view of an internal combustion engine equipped with a fuel supply device according to the present invention, and FIG. 2 is a side sectional view of a fuel supply device according to a modified embodiment of the present invention. 19: Heater 25: Fuel suction pipe 27: Liquefied gas container 32: Primary pressure regulator

Claims (3)

[Claims] (1) The fuel suction pipe is always protruded below the liquid level of the liquefied gas container, and while the engine is operating, the fuel in the liquefied gas container is supplied in liquid form to the mixer via the primary pressure regulator, and the fuel in the liquefied gas container is supplied to the mixer via the primary pressure regulator. A fuel supply system for an internal combustion engine, characterized in that a pipe connecting a pressure vessel is bypassed to a heat generating part of the engine. (2) A cylindrical liquefied gas container is supported horizontally on the engine,
The fuel supply device for an internal combustion engine according to claim 1, wherein the inner end side of the fuel suction pipe supported on the end wall of the liquefied gas container is curved below the liquefied gas container. (3) A cylindrical liquefied gas container is supported vertically on the engine,
The fuel supply device for an internal combustion engine according to claim (1), wherein the inner end side of the fuel suction pipe supported on the upper end wall of the liquefied gas container projects toward the inner surface of the lower end wall.