JP2569415Y2 - Liquefied fuel gas engine - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquefied fuel gas engine mounted on a portable working machine such as a backpack power sprayer or a brush cutter, and more particularly to a liquefied fuel gas engine capable of safely heating a fuel cylinder. It is.

[0002]

2. Description of the Related Art In a liquefied fuel gas engine which takes out vaporized fuel gas from a fuel cylinder storing liquefied fuel gas and supplies it to the engine body, the temperature in the fuel cylinder drops due to heat of vaporization, and the temperature in the fuel cylinder decreases. There is a problem that vaporization of the liquefied fuel gas is hindered.

Therefore, in the prior art, a fuel cylinder is heated by exhaust gas (for example, Japanese Utility Model Laid-Open No. 2-118158), and a chemical heating element is brought into contact with the fuel cylinder (for example, Japanese Utility Model Application Laid-Open No. HEI 2-118). No. 33999).

[0004]

The appropriate temperature of the fuel cylinder is about 40 ° C. at maximum, while the exhaust gas is high temperature (about 400 ° C. in the muffler) and heats the fuel cylinder. It will pass. Also, when heating the evaporator with a chemical heating element, it is necessary to add a chemical heating element as a heat source separately, and the chemical heating element is a consumable item. Need to be replaced.

[0005] An object of the present invention is to provide a liquefied fuel gas engine that can safely heat a fuel cylinder without adding a separate heat source. Another object of the present invention is to provide a liquefied fuel gas engine that can enhance the cooling effect of the engine body.

[0006]

The present invention will be described with reference to the drawings corresponding to the embodiments. In the liquefied fuel gas engine (10) which is a premise of the present invention, the fuel gas vaporized in the fuel cylinder (18) for storing the liquefied fuel gas is supplied into the engine body (30). In the liquefied fuel gas engine (10) of the present invention, the fuel cylinder (18) is housed in the housing box (12) having an air intake hole (22) for introducing external air, and the storage box (12) is provided. In 12), heat is exchanged with the surface of the fuel cylinder (18) whose temperature has been reduced due to the vaporization of the liquefied fuel gas, and the cooling air is passed through the cooling air passage (5) to the engine body (30).
8).

[0007]

In the liquefied fuel gas engine (10), the fuel gas is generated by vaporization from the liquefied fuel gas in the fuel cylinder (18), derived from the fuel cylinder (18), and supplied to the engine body (30). You. The cooling air flows through the cooling air flow path (58) toward the engine body (30), but in the middle of the fuel cylinder (1).
Exchange heat with 8). Thereby, the fuel cylinder (18)
The cooling air is heated and cooled, respectively, and the cooled cooling air cools the engine body (30).

[0008]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIG. 2 is a configuration diagram of the two-cycle liquefied fuel gas engine 10. The two-cycle liquefied fuel gas engine 10 is mounted on a portable working machine such as a backpack power sprayer or a brush cutter. The storage box 12 is such that the longitudinal direction is horizontal.
A box body 14 arranged and open at one end, and a box body
A lid 16 is provided so as to open and close the opening side of the fuel cell 14, and a fuel cylinder 18 is housed therein. The fuel cylinder 18 is housed in the box main body 14 from the opening side of the box main body 14 and pressed against the closed side of the box main body 14 by the compression coil spring 20. The pressing of the fuel cylinder 18 switches the open / close valve (not shown) on the top side to open, so that the fuel gas inside can be ejected. Air intake hole
Reference numeral 22 is formed in the box body 14 and the lid 16 to communicate the inside and outside of the storage box 12 with each other.

The air cleaner 24 includes a filter element 26 for filtering air.
30 Crankcase 42 communicates. The muffler 32 gradually reduces the pressure of the exhaust gas from the engine body 30,
Release to atmosphere.

The fuel passage 34 connects the discharge port of the fuel cylinder 18 to the mixer 28, and includes an opening / closing cock 36 and a pressure reducer 38 on the way. The open / close cock 36 is manually switched, and is closed when the operation of the two-cycle liquefied fuel gas engine 10 is stopped.

The engine body 30 includes a cylinder 40 and a crankcase 42, and an arc-shaped opening 44 is formed outside the crankcase 42 along the contour of the lower half of the crankcase 42. The outlet 46 is formed at an upper portion of the box body 14 and communicates with the crankcase 42.

FIG. 1 shows an air cooling structure of the engine body 30. The plurality of horizontal fins 48 are formed on the outer surface of the cylinder 40 at equal intervals in the vertical direction. Flywheel 50
Is attached integrally in the rotation direction to the end of a crankshaft 54 projecting horizontally from the crankcase 42, and a plurality of wind generations are formed at equal angular intervals in the circumferential direction around the end face on the engine body 30 side. It has a blade 52 for use. Engine cover 56
Covers the outside of the engine body 30 and the flywheel 50 in order to prevent a worker from touching the hot engine body 30. The arc-shaped opening 44 is formed between the crankcase 42 and the engine cover 56 on the side of the flywheel 50 below the flywheel 50, and communicates with the outlet 46 of the storage box 12 below the crankcase 42. ing. With the rotation of the flywheel 50, cooling air is generated by the wind generating blades 52, and the cooling air flows through the cooling air flow path 58 along a path indicated by an arrow in FIG. The storage box 12 is located at the start end of the cooling air flow path 58.

The operation of the embodiment will be described. The liquefied fuel gas is vaporized in the fuel cylinder 18 to become a fuel gas,
After the pressure is reduced in the pressure reducer 38, the pressure is supplied to the mixer 28. The temperature of the surface of the fuel cylinder 18 decreases as the liquefied fuel gas evaporates inside. The intake air is introduced from the air cleaner 24, filtered in the filter element 26, and then goes to the mixer 28 where the air is mixed with the fuel gas from the fuel passage 34 and introduced into the crankcase 42.

On the other hand, with the rotation of the flywheel 50,
Cooling air is generated by the wind generating blades 52, and the cooling air passes through the cooling air flow path 58 toward the cylinder 40 of the engine body 30. In the cooling air flow path 58, external air as a source of cooling air is introduced into the storage box 12 from the air intake hole 22 of the storage box 12, and performs heat exchange on the surface of the fuel cylinder 18. Thereby, the fuel cylinder 18 and the cooling air are heated and cooled, respectively, and the fuel cylinder 18 appropriately maintains the vaporization of the liquefied fuel gas inside. The cooling air cooled in the storage box 12 is:
It is led out from the inside of the storage box 12 through the outlet 46, and the arc-shaped opening 44
From the engine cover 56. Then, it is extruded from the central portion of the flywheel 50 to the peripheral portion, and turns in the direction of the cylinder 40 at the upper portion of the engine cover 56,
After passing through the fins 48, the cylinder 40 is cooled.

[0015]

In this invention, heat exchange is performed between the fuel cylinder and the cooling air to heat and cool the fuel cylinder and the cooling air, respectively, so that the fuel cylinder is safely heated and the engine body is cooled by the low-temperature cooling air. The cooling effect can be improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing an air cooling structure of an engine body.

FIG. 2 is a configuration diagram of a two-cycle liquefied fuel gas engine.

[Explanation of symbols]

10 Two-cycle liquefied fuel gas engine (liquefied fuel gas engine) 18 Fuel cylinder 30 Engine body 58 Cooling air flow path

Claims (1)

(57) [Scope of request for utility model registration] 1. A fuel cylinder (1) for storing liquefied fuel gas.
In the liquefied fuel gas engine (10) in which the fuel gas vaporized in 8) is supplied to the engine body (30), an external
Storage with open air intake hole (22) for introducing air
The fuel cylinder (18) is housed in the box (12),
In the box (12), the temperature decreases due to the vaporization of the liquefied fuel gas.
The cold exchanged heat with the surface of the lowered fuel cylinder (18).
The air却空, liquefied fuel gas engine, characterized in that communicating the cold却風passage (58) to said engine main body (30).