JP2592277Y2 - 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 work machine such as a backpack power sprayer or a brush cutter, and more particularly to a liquefied fuel gas engine capable of safely heating an evaporator. It is.

[0002]

2. Description of the Related Art In a liquefied fuel gas engine in which a liquefied fuel gas is taken out from a fuel cylinder storing the liquefied fuel gas and vaporized in an evaporator, the fuel gas is supplied to an engine body. Therefore, there is a problem that the temperature is lowered due to the heat of vaporization of the fuel gas and the vaporization of the liquefied fuel gas in the evaporator is hindered.

Therefore, in the prior art, the evaporator is heated by the exhaust gas (eg, Japanese Patent Publication No. 4-57865). Further, in a conventional liquefied fuel gas engine in which a fuel gas is generated by vaporizing a liquefied fuel gas in a fuel cylinder and the fuel gas is taken out from the fuel cylinder, the fuel cylinder is heated by an exhaust gas (for example, the fuel tank disclosed in Japanese Utility Model Application Laid-Open No. 2-118158). And a chemical heating element is brought into contact with a fuel cylinder (eg, Japanese Utility Model Laid-Open Publication No. 2-33999).

[0004]

When the evaporator is heated with the exhaust gas, the exhaust gas is heated to a high temperature (about 40 m in the muffler).
0 ° C.), the evaporator will be overheated.
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 an evaporator without adding a separate heat source. Another object of the present invention is to provide a liquefied fuel gas engine that can increase the cooling effect of the engine body.

[0006]

The present invention will be described with reference to the drawings corresponding to the embodiments. A liquefied fuel gas engine (10) which is a premise of the present invention includes a fuel cylinder (12), an evaporator (28) for vaporizing a liquefied fuel gas (18) discharged from the fuel cylinder (12), and an evaporator (28). An engine body (40) supplied with a liquefied fuel gas (18) from a vessel (28);
In a liquefied fuel gas engine (10) having cooling air generating means (52) driven by the engine body (40) to flow cooling air to the engine body (40), the evaporator (28) includes an engine body (40). Engine cover (5)
4) above the engine body (40).

[0007]

[Function] The liquefied fuel gas (18) remains in a liquid
It is taken out from (12) and led to the evaporator (28). And
The fuel gas is vaporized in the evaporator (28), and the fuel gas is supplied to the engine body (40). On the other hand, the cooling air
A predetermined cooling air passage generated by the cooling air generating means (52)
Flow through (58). The cooling air passes through the evaporator (28) before reaching the engine body (40), and heat exchange is performed between the evaporator (28) and the cooling air. As a result, the evaporator (28) and the cooling air are heated and cooled, respectively, and the cooling air cooled by the evaporator (28) cools the engine body (40).

[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 work machine such as a backpack power sprayer or a brush cutter.
The fuel cylinder 12 stores a liquefied fuel gas 18 therein and is stored in a storage box 14. The inlet of the outlet pipe 20 of the fuel cylinder 12 is located in the deep part of the liquefied fuel gas 18 in the fuel cylinder 12, and the fuel cylinder 12 is housed by being pushed into the storage box 14 and has a built-in on-off valve (not shown). Is opened, and the liquefied fuel gas 18 is discharged from the fuel cylinder 12 to the discharge section 16 as a liquid.

The fuel passage 22 connects the discharge portion 16 to an open / close cock 26,
The evaporator 28 is interposed and connected to the mixer 24.
Has a first-stage pressure reducer 30 and a second-stage pressure reducer 32. The liquefied fuel gas 18 is vaporized in the evaporator 28, reduced in a stepwise manner in the first-stage decompressor 30 and the second-stage decompressor 32, and then introduced into the intake passage 38 passing through the mixer 24. You. Open / close cock 26 is a two-stroke liquefied fuel gas engine
When the operation of 10 is stopped, the operation is manually switched to the closed state so that the supply of fuel to the engine body 40 can be stopped.

The air cleaner 34 has an annular filter element 36, and the intake passage 38 is formed by a path from the air cleaner 34 to the crankcase 46 of the engine body 40 (FIG. 1).

FIG. 1 shows an air cooling structure of the engine body 40. The engine body 40 includes a cylinder 42 having a plurality of horizontal fins 44 on the outer surface side, and a crankcase 46 below the cylinder 42. The flywheel 48 is integrally attached to the end of the crankshaft 50 projecting in the horizontal direction from the crankcase 46 in the rotational direction, and a plurality of flywheels are provided at equal angular intervals in the circumferential direction around the end face on the engine body 40 side. The wind generating blades 52 are provided. The engine cover 54 covers the outside of the engine body 40 and the flywheel 48 and forms an outer shape of a cooling air passage 58 in order to prevent an operator from touching the hot engine body 40. The arc-shaped opening 56 is formed between the crankcase 46 and the engine cover 54 on the side of the flywheel 48 below the flywheel 48 and communicates the inside and outside of the engine cover 54. With the rotation of the flywheel 48, a cooling wind is generated by the wind generating blades 52,
This cooling air flows through the cooling air passage 58 along the path indicated by the arrow in FIG. 1 and cools the cylinder 42.

In FIG. 1, the evaporator 28 is provided with a cooling air passage 5.
The cooling air passage 58 is located between the flywheel 48 and the engine body 40 in the engine cover 54 at the top of the engine 8.

The operation of the embodiment will be described. The liquefied fuel gas 18 is taken out of the fuel cylinder 12 to the discharge part 16 as it is in a liquid state, guided to the evaporator 28 via the opening / closing cock 26, and vaporized in the evaporator 28 to become a fuel gas. Fuel gas is
The pressure is reduced stepwise in the first-stage pressure reducer 30 and the second-stage pressure reducer 32 of the mixer 24, and is introduced into the intake passage 38 in the mixer 24. On the other hand, air is taken in from an air cleaner 34, and at that time, is filtered by a filter element 36,
The gas flows through the intake passage 38 to the mixer 24, where the gas flows into the mixer 24, is mixed with the fuel gas, and is introduced into the crankcase 46 of the engine body 40.

During operation of the two-stroke liquefied fuel gas engine 10, the flywheel 48 rotates with the rotation of the crankshaft 50, and the cooling blades 52 generate cooling air. The cooling air flows through the cooling air passage 58 and blows through between the fins 44,
The cylinder 42 is cooled. The cooling air exchanges heat with the evaporator 28 when passing through the evaporator 28 in the cooling air passage 58.
Thereby, the evaporator 28 and the cooling air are heated and cooled, respectively, so that the vaporization of the liquefied fuel gas 18 in the evaporator 28 is promoted, and the cooling effect of the cylinder 42 is improved.

[0015]

According to the invention, the evaporator is disposed above the cooling air passage so that heat is exchanged between the evaporator and the cooling air, so that the addition of a heat source is omitted. While
The cooling effect can be enhanced by safely heating the evaporator and sending low-temperature cooling air to the engine body.

[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]

DESCRIPTION OF SYMBOLS 10 Two-cycle liquefied fuel gas engine (liquefied fuel gas engine) 12 Fuel cylinder 18 Liquefied fuel gas 28 Evaporator 40 Engine main body 52 Wind generating blade (cooling air generating means) 58 Cooling air passage

Continuation of front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F02M 21/10 F01P 1/02

Claims (1)

(57) [Scope of request for utility model registration] 1. A fuel cylinder (12) , and said fuel cylinder
An evaporator (28) for vaporizing the liquefied fuel gas (18) released from the (12), and an engine body (40) supplied with the liquefied fuel gas (18) from the evaporator (28).
If, in order to flow the cooling air to the engine body (40) en
A liquefied fuel gas engine (10) having cooling air generating means (52) driven by a gin body (40 ).
In the above, the evaporator (28) is connected to the engine body (4).
0) The engine in the engine cover (54) covering the outside
A liquefied fuel gas engine characterized by being disposed above a fuel main body (40) .