JP2581962Y2 - Vertical multi-cylinder engine - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a vertical type multi-cylinder engine.

[0002]

2. Description of the Related Art For example, Japanese Patent Application Laid-Open No. 3-172570 discloses a vertical engine suitable for an outboard motor.
This engine is characterized in that each intake manifold extending from each cylinder head has the same length. In this way, the characteristics of each cylinder are made equal to maintain good engine performance.

[0003]

However, in order to make the intake manifolds of equal length, measures such as shifting the positions of the carburetors by an angle α, for example, as shown in FIGS. Need to be taken. In FIG. 3, the carburetor at the lowermost position moves away from the center of the engine, and the arrangement space for the carburetor increases accordingly.

Accordingly, an object of the present invention is to provide a technique capable of equalizing the intake passage while keeping the arrangement of the carburetors in a vertical line.

[0005]

In order to achieve the above object, the present invention is characterized in that the internal volume of the intake passage from the carburetor outlet to the intake valve is substantially the same for each cylinder. The inside diameter of at least one of the intake manifold passage and the cylinder head passage is different for each cylinder, and the carburetor outlet diameter and the intake valve diameter are the same for each cylinder.

[0006]

[Action] By making the internal volume of each intake passage substantially the same,
Eliminate variations in intake air between cylinders. By making the diameter of the outlet of the vaporizer the same, the arrangement of the vaporizer is facilitated,
In addition, machining of the cylinder head is facilitated by making the intake valve diameter the same.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the accompanying drawings. The drawings should be viewed in the direction of reference numerals.
FIG. 1 is a sectional side view of a main part of an outboard motor according to the present invention. An outboard motor 1 is mounted on an under case 2 as an engine mounting member and is water-cooled with bolts B1 (see FIG. 2). An engine 3, an oil pan 4 mounted under the undercase 2 with bolts B2, an extension case 5 also mounted under the undercase 2 with bolts B3, and a vertical drive shaft housed in the extension case 5. 6, a bevel gear set 7 housed in a gear case 5b also attached to the lower part of the extension case 5, a cooling water supply pipe 8 and a water pump 9 also housed in the extension case 5 and the gear case 5b. Outboard motor body 1A and the outboard motor body 1
A includes an outboard motor mounting means 12 which is bolted to A through anti-vibration rubbers 11U and 11L.

The outboard motor mounting means 12 is a metal fitting for fixing the outboard motor 1 to the hull, and swings the outboard motor main body 1A right and left in a plan view around a swivel shaft 13, and a tilt shaft. 1
The outboard motor main body 1A including the swivel shaft 13 around the center 4 can be flipped clockwise in the drawing. The under case 2 surrounds the water-cooled engine 3 together with the removable engine cover 15.

FIG. 2 is a side sectional view of the water-cooled engine according to the present invention. In the water-cooled engine 3, the axis of the cylinder 31 is oriented substantially horizontally and the crankshaft 32 is oriented vertically. The joint surface is a substantially vertical surface, and a camshaft 36 and rocker shafts 37, 37 are housed in a valve operating chamber 35 formed in a cylinder head 34. The camshaft 36 is connected to a crankshaft 32 via a timing belt 38 and a cam pulley 38a. Driven accurately.

In the lower part of the cylinder head 34, a horizontal oil return passage 39 (an opening 39a at one end is provided with a valve operating chamber 35).
), And a bend-type oil return passage 40 is formed in the cylinder block 33, and a vertically-oriented oil return passage 41 is formed in the under case 2 so as to be connected. In addition, the bend type oil return passage 40 of these cylinder blocks 33
A cooling water passage 43B is arranged near the oil return passage 41 of the under case 2 and closer to the hull than the passages 40 and 41. The cooling water passage 43B faces the water jacket 3A on the water-cooled engine 3 side. On the other hand, as shown in FIG. 1, the cooling water passage 43B is
C, and cools the anti-vibration rubber 11U with cooling water from the cooling water supply pipe 8.

An upper end flange of an oil return pipe 44 is in contact with a peripheral wall of a lower end opening portion of the vertical oil return passage 41 and is bolted. An oil suction pipe 45 is attached to the front side of the oil return pipe 44 in the drawing, and an oil passage connected to this pipe 45 is omitted in the middle and is not shown, but extends to a suction port of an oil pump 47 attached to a lower portion of the cam shaft 36. Extending (see FIG. 1).

FIG. 3 is a side view of the vertical type multi-cylinder engine according to the present invention, in which a first carburetor 51, a second carburetor 52, and a third carburetor 53 are arranged vertically in a side of a cylinder block 33. The outlets of the carburetors 51, 52, 53 are connected to an intake manifold 55, and the intake manifold 55 is fixed to the cylinder head 34 with bolts B4. In addition. The first carburetor 51 at the uppermost position is lower than the flywheel 38a (see FIG. 5). The third carburetor 53 at the lowermost position is higher than the under cover 2. Therefore, the plurality of vaporizers 51, 52, 53 are arranged within a limited height range.

On the other hand, a fuel pump 56 is mounted on the lower side of the cylinder head 34. The pump 56 is driven by the accessory cam 36a shown in FIG. The fuel is pressurized by a fuel pump 56 and sent to vaporizers 51 to 53 via a fuel tube 57. The air is sent to the vaporizers 51 to 53 via the air silencer 58.

FIG. 4 is a sectional view taken along line 4-4 in FIG. 3, in which an intake valve 61 and an exhaust valve 62 face the cylinder 31 and the intake valve 6
1 and the exhaust valve 62 are driven by the camshaft 36 via rocker arms 63, 63. An air silencer 58, a carburetor 51, and an intake manifold 55 are provided beside the cylinder block 33.
And a mixture of air and fuel is supplied from the carburetor outlet 51a to the cylinder 31 via the intake manifold passage 65 and the cylinder head passage 66.

FIG. 5 is a view taken in the direction of arrows 5-5 in FIG. 4, and shows the positional relationship among the flywheel, the carburetor, the intake manifold, and the cylinder head. As described above, the uppermost first carburetor 51 is arranged at a position below the level of the flywheel 38a and as high as possible without interfering with the flywheel 38a. Hereinafter, the second carburetor 52 and the third carburetor 53 are sequentially arranged at intervals in consideration of the size, installation, and maintenance of the carburetor itself. The first carburetor 51, the second carburetor 52, and the third carburetor 53 are characterized in that they are arranged vertically in a line along a longitudinal axis L20 parallel to the longitudinal axis L10 of the engine. Therefore, the connecting link 67 connecting the levers of the vaporizers 51 to 53 is also parallel to the longitudinal axis L10.

Returning to FIG. 4, the internal volume of the intake manifold passage 65 formed in the intake manifold 55 is represented by Vn.
(N = 1, 2, 3) is represented by the product of the average internal cross-sectional area of the passage and the axial length. Similarly, the internal volume of the cylinder head passage 66 formed in the cylinder head 34 is represented by Wn (n =
1, 2, 3) is represented by the product of the average internal cross-sectional area of the passage and the axial length.

In FIG. 5, the outlet 51 of the first vaporizer 51
a, outlet 52a of second vaporizer 52 and third vaporizer 53
Are all the same, and (V1 + W1), (V2 + W2) and (V3 + W3) are almost the same,
It is characterized in that the diameters of the intake holes 68, 69, 70 of the cylinder head 34 are all the same. Intake holes 68, 69, 7
If the diameters of 0 are the same, the intake valves 61, 61, 61 that open and close them (FIG. 4) also have the same diameter. Also, the diameter of each hole at the joint surface between the intake manifold 55 and the cylinder 34 is the same, and each length Ln of the intake manifold 55 is
(N = 1, 2, 3) and the respective diameters Rn (n = 1, 2, 3) are substantially adjusted, at which time W1, W2, W3 are taken into account.

The operation of the vertical multi-cylinder engine having the above configuration will be described below. In FIG. 3, combustion air is taken into a first carburetor 51, a second carburetor 52, and a third carburetor 53 via an air silencer 58, and fuel is supplied via a fuel pump 56 and a fuel tube 57. It is. Thereafter, the air-fuel mixture is blown into the cylinders 31, 31, 31 through the intake manifold passage 65 and the cylinder head passage 66 shown in FIG. At this time,
As shown in FIG. 5, the intake passage of the first carburetor 51,
Since the intake passage of the second carburetor 52 and the intake passage of the third carburetor 53 have substantially the same internal volume,
The intake air between the cylinders 31, 31, 31 is uniform. If the intake air is uniform, the combustion becomes the same, and a predetermined engine output can be obtained.

The vertical type multi-cylinder engine 3 of the present invention is suitable for an outboard motor (see FIG. 1) which requires a small engine since the arrangement of the carburetor and the intake manifold is good and the output can be obtained at a high level. It is.

[0020]

[Effect of the Invention] As described above, in the present invention, the internal volume of the intake passage from the carburetor outlet to the intake valve is substantially the same for each cylinder, so that the variation in intake air between the cylinders can be eliminated. A predetermined engine output can be obtained.

In addition , the inside diameter of at least one of the intake manifold passage and the cylinder head passage is different for each cylinder, and the outlet diameter of the carburetor and the intake valve diameter are the same for each cylinder. The arrangement of the carburetor is facilitated, and the processing of the cylinder head is facilitated by making the intake valve diameter the same.

[Brief description of the drawings]

FIG. 1 is a sectional side view of a main part of an outboard motor according to the present invention.

FIG. 2 is a side sectional view of the vertical multi-cylinder engine according to the present invention.

FIG. 3 is a side view of the vertical multi-cylinder engine according to the present invention.

FIG. 4 is a sectional view taken along line 4-4 in FIG. 3;

FIG. 5 is a view taken in the direction of arrows 5-5 in FIG. 4;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Outboard motor, 3 ... Vertical type multi-cylinder engine, 31 ...
Cylinder, 32 ... crankshaft, 33 ... cylinder block, 34 ... cylinder head, 38a ... flywheel,
51 ... first vaporizer, 51a ... first vaporizer outlet, 52 ...
Second carburetor, 52a: outlet of the second carburetor, 53: third carburetor, 53a: outlet of the third carburetor, 55: intake manifold, 61: intake valve, 65: passage in the intake manifold,
66 ... Cylinder block passage.

──────────────────────────────────────────────────の Continued on front page (51) Int.Cl. ⁶ Identification code FI B63H 21/26 Z

Claims (1)

(57) [Scope of request for utility model registration] 1. A crankshaft is disposed substantially vertically, a flywheel is disposed at an upper end of the crankshaft, and a carburetor, a passage in an intake manifold is provided in each of the stacked cylinders having a substantially horizontal axis in a side view. a cylinder head passage, the air-fuel mixture through the intake valve is supplied, before Symbol plurality of vaporizers are arranged in tandem on the side of the cylinder block, the intake manifold passage vertical type is substantially horizontal multi a cylinder engine was the internal volume of the intake passage from the previous SL vaporizer outlet to the intake valve at substantially the same in each cylinder Bartica
In the multi-cylinder engine, the passage in the intake manifold and the passage in the cylinder head
At least one inside diameter is different for each cylinder,
Each of the inside diameter of the carburetor outlet and the diameter of the intake valve is
A vertical type multi-cylinder engine characterized by the same characteristics.