JPH0660762U - Vertical type multi-cylinder engine - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a technique capable of equalizing the intake passages while keeping the carburetors arranged in a line. [Structure] The internal volume (Vn + Wn) of the intake passage from the outlet 51a of the carburetor 51 to the intake valve 61 is determined by the cylinder 31
Both are almost the same.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to improvement of a vertical type multi-cylinder engine.

[0002]

[Prior art]

 For example, Japanese Patent Application Laid-Open No. 3-172570 discloses a vertical engine suitable for an outboard motor. This engine is characterized by each intake manifold extending from each cylinder head being of equal length. As a result, the characteristics of each cylinder are made equal, and the performance of the engine is kept good.

[0003]

[Problems to be solved by the device]

 However, in order to make the intake manifolds of equal length, it is necessary to take measures such as shifting the positions of the carburetors by an angle α, as shown in FIGS. 3 and 4 of the above publication. In FIG. 3, the carburetor at the lowest position moves away from the center of the engine, and the carburetor arrangement space increases accordingly.

Therefore, an object of the present invention is to provide a technique capable of equalizing the intake passages while keeping the carburetors arranged in a line.

[0005]

[Means for Solving the Problems]

 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 made substantially the same in each cylinder. The inner diameter of at least one of the intake manifold internal passage and the cylinder head internal passage shall be different for each cylinder, and the carburetor outlet diameter and intake valve diameter shall be the same for each cylinder.

[0006]

[Operation] By making the inner volumes of the intake passages substantially the same, the variation of intake air between the cylinders is eliminated. By making the outlet diameter of the carburetor the same, the arrangement of the carburetor is facilitated, and by making the intake valve diameter the same, machining of the cylinder head is facilitated.

[0007]

【Example】

 Embodiments of the present invention will be described below with reference to the accompanying drawings. The drawings should be viewed in the direction of the reference numerals. FIG. 1 is a cross-sectional side view of a main part of an outboard motor according to the present invention. The outboard motor 1 is placed on an undercase 2 as an engine mounting member and is water-cooled by a bolt B1 (see FIG. 2). The engine 3, the oil pan 4 attached to the under case 2 with the bolt B2, the extension case 5 also attached to the under case 2 with the bolt B3, and the vertical drive shaft housed in the extension case 5. 6, a bevel gear set 7 housed in a gear case 5b that is also attached to the lower part of the extension case 5, and a cooling water supply pipe 8 and a water pump 9 that are also housed in the extension case 5 and the gear case 5b. The outboard motor body 1A and the outboard motor body 1A bolted to the outboard motor body 1A via vibration-proof rubbers 11U and 11L. Consisting of means 12.

The outboard motor mounting means 12 is a metal fitting for fixing the outboard motor 1 to the hull, and swings the outboard motor body 1A left and right in plan view about the swivel shaft 13 and tilts. The outboard motor body 1A including the swivel shaft 13 around the shaft 14 can be flipped up in the clockwise direction in the drawing. The under case 2 encloses the water-cooled engine 3 together with an engine cover 15 which can be attached and detached thereto.

FIG. 2 is a side sectional view of a water-cooled engine according to the present invention. In the water-cooled engine 3, a cylinder block 33 and a cylinder block 33 are provided with a cylinder 31 having a substantially horizontal axis and a vertical crankshaft 32. The joint surface of the head 34 is a substantially vertical surface, and a cam shaft 36 and rocker shafts 37, 37 are housed in a valve operating chamber 35 formed in the cylinder head 34. The cam shaft 36 is cranked by a timing belt 38 and a cam pulley 38a. It is precisely driven by the shaft 32.

Then, a horizontal oil return passage 39 (the opening 39 a at one end faces the valve operating chamber 35) is provided under the cylinder head 34, a bend type oil return passage 40 is provided in the cylinder block 33, and a vertical orientation is provided in the under case 2. The oil return passage 41 is formed in a connected state. In addition, a cooling water passage 43B is arranged close to the bend type oil return passage 40 of the cylinder block 33 and the oil return passage 41 of the undercase 2 and closer to the hull than the passages 40, 41. The cooling water passage 43B faces the water jacket 3A on the water cooling engine 3 side. On the other hand, as shown in FIG. 1, the cooling water passage 43B is connected to the cooling water passages 43A and 43C, and the vibration isolation rubber 11U is cooled by the cooling water from the cooling water supply pipe 8.

An upper end flange of an oil return pipe 44 is brought into contact with and bolted to a peripheral wall of a lower end opening portion of the vertically oriented oil return passage 41. An oil suction pipe 45 is attached to the front side of the oil return pipe 44 in the figure, and an oil passage connected to this pipe 45 is omitted in the middle but not shown, but a suction port of an oil pump 47 attached to the lower part of the camshaft 36. (See Figure 1).

FIG. 3 is a side view of a vertical multi-cylinder engine according to the present invention, in which a first carburetor 51, a second carburetor 52, and a third carburetor 53 are vertically arranged in a row on the side of the cylinder block 33. The outlets of these carburetors 51, 52, 53 are connected to an intake manifold 55, and the intake manifold 55 is fixed to the cylinder head 34 with a bolt B4. Incidentally. The uppermost first carburetor 51 is positioned below the flywheel 38a (see FIG. 5). The lowermost third vaporizer 53 is positioned above the undercover 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 attached to the lower portion of the side surface of the cylinder head 34. The pump 56 is driven by the auxiliary equipment cam 36a shown in FIG. The fuel is pressurized by the fuel pump 56 and sent to the vaporizers 51 to 53 via the 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 of FIG. 3, in which the intake valve 61 and the exhaust valve 62 face the cylinder 31, and the intake valve 61 and the exhaust valve 62 are connected via the rocker arms 63 and 63 to the camshaft 3. Driven by 6. An air silencer 58, a carburetor 51, and an intake manifold 55 are arranged on the side of the cylinder block 33. A mixture of air and fuel flows from the carburetor outlet 51a to an intake manifold internal passage 65 and a cylinder head internal passage 66. It is supplied to the cylinder 31 via.

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 higher position below the level of the flywheel 38a within the range where it does not interfere with it. Hereinafter, the second vaporizer 52 and the third vaporizer 53 are sequentially arranged at intervals considering the size of the vaporizer itself, installation, and maintenance. The first carburetor 51, the second carburetor 52, and the third carburetor 53 are arranged in a vertical line along a vertical 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 internal passage 65 formed in the intake manifold 55 is Vn (n = 1, 2, 3) is the product of the average internal cross-sectional area of the passage and the axial length. It is represented by. Similarly, the internal volume Wn (n = 1, 2, 3) of the cylinder head internal passage 66 formed in the cylinder head 34 is represented by the product of the average internal cross-sectional area of the passage and the axial length.

In FIG. 5, the outlet 51a of the first vaporizer 51, the outlet 52a of the second vaporizer 52, and the outlet 53a of the third vaporizer 53 have the same diameter, and are (V1 + W1) and (V2 + W2). And (V3 + W3) are almost the same, and the diameters of the intake holes 68, 69, 70 of the cylinder head 34 are all the same. If the diameters of the intake holes 68, 69, 70 are the same, the intake valves 61, 61, 61 (FIG. 4) for opening and closing them also have the same diameter. Further, each hole diameter in the joint surface between the intake manifold 55 and the cylinder 34 is also the same, and each length Ln (n = 1, 2, 3) and each diameter Rn (n = 1, 2, 3) of the intake manifold 55. Substantially adjusted by and, at which time W1, W2, W3 are considered.

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

Since the vertical multi-cylinder engine 3 of the present invention has a good carburetor and intake manifold arrangement and high output, it is suitable for an outboard motor (see FIG. 1) that requires a small engine. Is.

[0020]

[Effect of device]

 As described above, in the present invention, the internal volume of the intake passage from the carburetor outlet to the intake valve is made substantially the same for each cylinder, so it is possible to eliminate the variation in intake air between cylinders, and to obtain a predetermined engine output. Obtainable.

Further, the inner diameter of at least one of the intake manifold internal passage and the cylinder head internal 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 carburetor can be arranged easily, and the cylinder diameter can be made uniform by making the intake valve diameter the same.

[Brief description of drawings]

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

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

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

FIG. 4 is a sectional view taken along line 4-4 of FIG.

5 is a view on arrow 5-5 of FIG.

[Explanation of symbols]

1 ... Outboard motor, 3 ... Vertical multi-cylinder engine, 31 ...
Cylinder, 32 ... Crankshaft, 33 ... Cylinder block, 34 ... Cylinder head, 38a ... Flywheel,
51 ... 1st vaporizer, 51a ... Outlet of 1st vaporizer, 52 ...
2nd vaporizer, 52a ... 2nd vaporizer outlet, 53 ... 3rd vaporizer, 53a ... 3rd vaporizer outlet, 55 ... Intake manifold, 61 ... Intake valve, 65 ... Intake manifold internal passage,
66 ... Passage in cylinder block.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display area F02M 13/02 Z 9038-3G

Claims (2)

[Scope of utility model registration request] 1. A crankshaft is placed substantially vertically, a flywheel is arranged at an upper end of the crankshaft, and a carburetor and an intake manifold internal passage are provided in each of cylinders whose axes are substantially horizontal in a side view and stacked. A multi-cylinder engine in which an air-fuel mixture is supplied through a passage in a cylinder head and an intake valve,
In a vertical multi-cylinder engine in which the plurality of carburetors are arranged in a line vertically to the side of a cylinder block, and the passages in the intake manifold are substantially horizontal, the engine has an intake air from the carburetor outlet to an intake valve. A vertical multi-cylinder engine characterized in that the internal volume of the passage is almost the same for each cylinder. 2. The inner diameter of at least one of the intake manifold internal passage and the cylinder head internal passage is different for each cylinder, but the inner diameter of the carburetor outlet and the intake valve diameter are the same for each cylinder. The vertical type multi-cylinder engine according to claim 1.