JPS5847214Y2 - Tategata Kyouseiku Ureishiki Engine Nikokeru Nenryyou Tankno Reikiyaku Kouzou - Google Patents

Description

[Detailed Description of the Invention] The present invention is aimed at a vertical forced air-cooled engine, and attempts to effectively ventilate and cool the fuel tank mounted on the cylinder head of the engine.

Conventionally, in this type of engine, the fuel tank was mounted and fixed with a slight gap above the cylinder head, and the fuel tank, especially the bottom surface, was cooled by natural ventilation.

However, since the fuel tank receives conductive heat from the cylinder head through the mounting bolts that fix it, and receives radiant heat through the mounting gap, it tends to become overheated.

As a result, the fuel in the fuel tank heats up and evaporates, causing the paper to pass through the breather installed in the fuel filler cap.
Not only was it uneconomical as it evaporated from the water, but it was also dangerous.

In view of this, the present invention attempts to forcefully and efficiently cool the fuel tank in this type of vertical forced air-cooled engine by extracting a portion of the cooling air and bringing it into direct contact with the bottom of the fuel tank. It is something to do.

Hereinafter, one embodiment of the present invention will be described based on the drawings.

The drawing shows an engine generator using a vertical forced air-cooled engine, and a generator 2 is installed at the rear of the engine body 1.
are directly connected.

The engine body 1 has a cylinder head 3 on which a fuel tank 4 is mounted and fixed, as will be described later.

A fan cover 5 is attached to the front of the engine body 1, a head cover 1 is attached to the upper surface of the cylinder head 3 via stud bolts 6, and a cowling 9 is attached to the outer peripheral surface of the cylinder 8, and a cooling fan is fixed to one end of the crankshaft 10. At 11, outside air is taken into the fan cover 5 from the front outside air intake 12, guided to the upper part of the fan cover 5, and is blown from the outlet 13 to the cylinder head 3 and cylinder 8 side to forcibly cool them. It has a known structure.

Therefore, the present proposal is based on the above forced air cooling structure.
The herad cover 1 is connected to the upper end edge of the outlet 13 of the fan cover 5 at a lower level than this.

Thereafter, the mounting base 15 is mounted and fixed on the head cover 1 using the stud bolts 6 in common.

The mounting base 15 has a U-shaped cross section with openings on the top and front and rear surfaces, and the fuel tank 4 is fitted and supported on the mounting base 15, and the mounting collar 16 on the body of the fuel tank 4 is attached to the left and right side plates 15a of the mounting base 15, It is fixed to the upper edge of 15a with a bolt 17.

The bottom plate 15b of this mounting base 15 and the bottom surface 4a of the fuel tank 4
A gap is provided between them, and this constitutes a front-rear ventilation passage a.

The head cover 7 has a connecting part to the fan cover 5,
Ventilation port 1 communicating with the upper end of the outlet 13 of the fan cover 5
8, the front end opening surface of the ventilation path a is exposed to the ventilation port 18, and the rear end opening surface of the ventilation path a is opened directly to the atmosphere.

In such a case, most of the outside air introduced into the fan cover 5 is guided by the cooling fan 11 through its outlet 13 to the head cover 1 and the cowling 9, and then cooled to the cylinder head 3.
Air is blown to the cylinder 8 to cool them.

A portion of the cooling air then passes through the upper end of the outlet 13 to the ventilation port 18, exits the head cover γ, passes through the ventilation path a formed inside the mounting base 15, and is discharged to the atmosphere.

The cooling air passing through this ventilation path a is directly transmitted to the bottom surface 4 of the fuel tank 4.
a and forcedly cools it through ventilation.

Therefore, due to conduction heat applied from the cylinder head 3 side to the head cover 7 and the bottom plate 15b of the mounting base 15 via the stud bolts 6, and radiant heat from the cylinder head 3,
The bottom surface 4a of the fuel tank 4 is not heated.

As described above, the present invention protects the fuel tank from heating due to conduction heat and radiation heat by forcing part of the cooling air that cools the engine body into the ventilation path formed by the fuel tank mounting base. This allows the fuel tank to be efficiently cooled.

Moreover, since the mounting base of the fuel tank also serves as the air guide plate, the structure is simple and the cross-sectional area of the tank cooling air passage can be easily and accurately set.

In addition, the head cover is connected to the upper edge of the cooling air outlet of the fan cover so as to be located at the bottom of the upper edge of the cooling air outlet of the fan cover, and a cooling air flow is formed along the bottom surface of the fuel tank at the connecting part of the head cover to the fan cover. Since the ventilation port is opened in this state, the cooling air flowing into the ventilation path can be smoothly distributed along the bottom surface of the tank.

Furthermore, since the head cover is fixed collinearly with the tank mounting base, it is possible to reliably prevent chatter of the head cover from insects, and it has the advantage that it can be easily applied to existing vertical air-cooled engines.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a vertical side view;
FIG. 2 is a sectional view taken along line A--A in FIG. 1. 1...Engine body, 3...Cylinder head, 4...Fuel tank, 4a...
Bottom of 4, 5...Fan cover, 13...
...Exit of 5, 15...Mounting base, a...
・Ventilation duct.

Claims (1)

[Scope of utility model registration request] The front surface of the engine body 1 is covered with a fan cover 5, and the upper surface of the cylinder head 3 is covered with a head cover 7. The head cover 7 is extended from the upper edge, and the fuel tank mounting base 15, which has a U-shaped cross section, is positioned so that the side opening faces the cooling air outlet 13.
This mounting base 15 is fixed to the cylinder head 3 collinearly with the head cover 7, and the mounting collar 16 of the body of the fuel tank 4 is fixed to the upper edges of the left and right side plates 15a, 15b of the mounting base 15. Then, connect the bottom surface 4a of the fuel tank 4 and the mounting base 1.
The space between the head cover 7 and the bottom plate 15a of the fuel tank 5 is also formed into a ventilation passage a, and the ventilation opening 18 is opened at the connection part of the head cover 7 to the fan cover 5 so as to form a flow along the bottom surface of the fuel tank. A cooling structure for a fuel tank in a vertical forced air-cooled engine, characterized in that a cooling air outlet 13 and a starting end of a ventilation passage a are communicated with each other, and a terminal end of the ventilation passage a is opened to the atmosphere.