JPH0474527B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a vertical general-purpose internal combustion engine, and more particularly to an arrangement structure of an intake system and an exhaust system of a four-stroke vertical general-purpose internal combustion engine.

(Prior Art) Vertical type general-purpose internal combustion engines with vertically disposed crankshafts are widely used as engines for working machines for agricultural work, civil engineering work, and the like.

In such a vertical general-purpose internal combustion engine, conventionally,
Utility Model Application Publication No. 55-154315, Utility Model Application Publication No. 1987-106322, Utility Model Application No. 56-118969, JP-A-59-70838
As disclosed in the publication, the lower part of the crankshaft is used as an output extraction part, and a fan is attached to the upper part of the crankshaft, and this fan generates cooling air to cool the engine. .

However, with the conventional structure, especially
As disclosed in Publication No. 70838, an intake hole and an exhaust hole are opened on the sides of the cylinder that are opposite to each other at 180 degrees, and a carburetor is disposed on the side of the cylinder where the intake hole is opened. A carburetor is connected to the hole, a muffler is placed on the side of the cylinder where the exhaust hole is opened, and the exhaust hole and the muffler are connected by an exhaust pipe.

(Problems to be Solved by the Invention) Therefore, in conventional vertical type general-purpose internal combustion engines, it is difficult to ensure a long exhaust length from the exhaust hole to the muffler, which is disadvantageous in reducing exhaust noise.

The present invention has been devised in view of the above circumstances, and an object of the present invention is to provide a vertical type general-purpose internal combustion engine that can be made compact and reduce exhaust noise.

(Means for Solving the Problems) In order to solve the above problems and achieve the object, the present invention has a crankshaft 5 having one end serving as an output portion 5A, which is disposed vertically, and a cylinder 7 which is arranged substantially horizontally. In a four-stroke vertical general-purpose internal combustion engine 1, an exhaust hole 27 is opened on the outer surface 7B of the cylinder located on the output section 5A side of the crankshaft 5, and the cylinder outer surface 7A is substantially orthogonal to the exhaust hole 27. The intake hole 25 is opened to the outside surface 7A of the cylinder where the intake hole 25 is opened.
A carburetor 31 is disposed in the cylinder, the carburetor 31 is connected to the intake hole 25, and a muffler 37 is disposed on the cylinder outer surface 7C opposite to the cylinder outer surface 7A on which the carburetor 31 is disposed. , an exhaust pipe 39 connected to the exhaust hole 27
The exhaust pipe 39 is bent 39B toward the cylinder outer surface 7C where the muffler 37 is disposed, and the exhaust pipe 39 is connected to the muffler 3.
It is characterized by being connected to 7.

(Function) The carburetor 31 and the muffler 37 are arranged on both sides of the cylinder 7 to make the engine more compact. In addition, exhaust hole 2
Since the cylinder side surface 7B where 7 is opened and the cylinder side surface 7C where the muffler 37 is disposed are different, the exhaust hole 2
A large exhaust length from 7 to the muffler 37 can be ensured, and exhaust noise can be reduced.

(Embodiment) A preferred embodiment of the present invention will be described below with reference to the accompanying drawings.

Figure 1 is a perspective view of a vertical general-purpose internal combustion engine.
Figure 2 is a plan view, Figures 3 to 6 are views seen from the arrows, arrows, arrows, and arrows in Figure 2, respectively;
FIG. 7 shows a bottom view.

For convenience, the arrow side in FIG. 2 will be described as the front, the arrow side as the rear, the arrow side as the left, and the arrow side as the right.

A crankshaft 5 is disposed vertically in the crankcase 3 of the vertical general-purpose internal combustion engine 1, and a first
As shown in the drawings and FIG. 4, a cylinder 7 is provided horizontally projecting from the left side of the crankcase 3.

In the figure, numeral 9 indicates a head cover, and the vertical general-purpose internal combustion engine 1 is an overhead valve type (including an overhead camshaft type) four-stroke internal combustion engine in which an intake valve and an exhaust valve are disposed directly above a combustion chamber.

The crankshaft 5 is made to protrude from the upper and lower surfaces of the crankcase 3, and the lower part of the crankshaft 5 protruding from the lower surface of the crankcase 3 is connected to the output extraction section 5A.
used as

Reference numeral 11 denotes a fan cover, and the fan cover 11 is provided above the upper surface of the crankcase 3 and above the upper surface of the cylinder 7.

An opening is provided in a portion of the fan cover 11 above the upper surface of the crankcase 3, and a cover 15 having a plurality of elongated cooling air intakes 13 is attached to the opening.

A fan (not shown) is attached to a portion of the crankshaft 5 protruding from the upper surface of the crankcase 3, and a recoil starter device 17 is disposed within the cover 15 above the crankshaft 5. Connect to the upper end of 5.

The engine is cooled by generating cooling air using a fan, taking in outside air from a cooling air intake port 13, and impinging the cooling air on the cylinder 7 side under the guidance of a fan cover 11.

As shown in FIGS. 1 and 2, a fuel tank 21 is provided in front of the front surface of the fan cover 11, and an air cleaner 23 is provided on the left side of the fuel tank 21 and in front of the left end of the front surface of the fan cover 11. .

As shown in FIG. 7, an intake hole 25 is formed in the front surface 7A of the cylinder 7, and an exhaust hole 25 is formed in the lower surface 7B of the cylinder 7.
7 and the rear surface 7 of the cylinder 7 as shown in FIG.
Attach the spark plug 29 from the C side.

A carburetor 31 is disposed below the air cleaner 23 in front of the front surface 7A of the cylinder 7.

The carburetor 31 is connected to the intake hole 25, and the L
It is connected to the air cleaner 23 through a letter-shaped connecting tube 33.

Fuel is supplied to the carburetor 31 through a fuel pipe 35 connected to the fuel tank 21.

37 is a muffler, and the muffler 37 is the rear surface 7 of the cylinder 7.
Placed at the rear of C.

As shown in FIG. 7, the exhaust pipe 39 has an upstream end 39A.
is connected to the exhaust hole 27. Exhaust pipe 39 is exhaust hole 2
7 and then extends rearward through the bent portion 39B, and the downstream end 39C is connected to the muffler 37. Note that 41 in FIG. 6 indicates an exhaust outlet.

Since this embodiment is configured as described above, the cylinder 7
Since the carburetor 23 and the muffler 37 are located on both sides of the engine, the vertical height can be lowered and the engine can be made more compact.

Further, the cylinder side surface 7B in which the exhaust hole 27 is formed
Since this is different from the cylinder side surface 7C where the muffler 37 is disposed, a large length of the exhaust pipe 39 from the exhaust hole 29 to the muffler 37 can be ensured, and therefore exhaust noise can be reduced.

In addition, in the embodiment, an exhaust hole 27 is provided in the side surface 7B of the cylinder 7 located on the output extraction side 5A of the crankshaft 5.
Since the exhaust pipe 39 is located on the downstream side of the flow of cooling air, this is advantageous in cooling the engine.

(Effects of the Invention) As is clear from the above description, according to the present invention, it is possible to obtain a four-stroke vertical type general-purpose internal combustion engine that can be made compact and reduce exhaust noise.

[Brief explanation of the drawing]

Figure 1 is a perspective view of a vertical general-purpose internal combustion engine.
Figure 2 is a plan view, Figures 3 to 6 are views seen from the arrows, arrows, arrows, and arrows in Figure 2, respectively;
FIG. 7 shows a bottom view. In the figure, 3 is the crankcase, 5 is the crankshaft,
7 is a cylinder, 25 is an intake hole, 27 is an exhaust hole, 31 is a carburetor, 37 is a muffler, and 39 is an exhaust pipe.

Claims (1)

[Scope of Claims] 1. In a four-stroke vertical general-purpose internal combustion engine in which a crankshaft with one end serving as an output portion is disposed vertically and cylinders are provided approximately horizontally, a crankshaft located on the output portion side of the crankshaft. An exhaust hole is opened on the outside surface of the cylinder where the exhaust hole is opened, an intake hole is opened on the outside surface of the cylinder that is almost perpendicular to this exhaust hole, and a carburetor is arranged on the outside surface of the cylinder where the intake hole is opened. is connected to the intake hole, a muffler is provided on the outer surface of the cylinder opposite to the outer surface of the cylinder where the carburetor is provided, and an exhaust pipe connected to the exhaust hole is provided with the muffler. A four-stroke vertical general-purpose internal combustion engine, characterized in that the exhaust pipe is bent toward the outer surface of the cylinder and connected to the muffler.