JPH07224627A - Two-cycle engine - Google Patents

Abstract

PURPOSE:To provide a 2-cycle engine capable of improving maintenance workability, and the structure simplification and cost reduction, etc., of an oil pipeline. CONSTITUTION:An oil pump 32 is arranged in a lower side than the top of a cylinder head 17 in an upper side than the crank shaft 4 of a 2-cycle engine 1, and also an oil tank 38 is arranged in the upper side of the oil pump 32. Arranging the oil pump 32 on the upper part of the engine 1 further increases workability for maintenance such as the air vent or change, etc., of the oil pump 32. Also since the oil pump 32 and the oil tank 38 are together fitted to the engine 1, the structure simplification of an oil pipeline 39 can be realized, and moreover relative movement (vibration) is not caused in the oil pipeline 39, consequently a high function is not needed to the oil pipeline 39 to realize the cost reduction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-stroke engine which employs a dry sump system as a lubrication system.

[0002]

2. Description of the Related Art As a marine engine, a small and lightweight two-cycle engine is required due to the limitation of installation space, and among them, a crank chamber compression system which can be miniaturized is desired. As a lubrication method, the dry sump method is advantageous from the viewpoint of simplification of the structure, and development related to this method is underway.

[0003]

By the way, in a conventional marine engine, for example, an oil pump is attached to the lower part of the engine, and the oil pump is driven by a balancer mechanism or the like. Since it is located below, there is a problem that the workability of maintenance such as air bleeding of the oil pump when the engine is started and replacement of the oil pump is poor.

Further, since the oil tank is installed on the hull side separately from the engine, relative movement (vibration) occurs in the oil pipe connecting the oil pump and the oil tank,
There is a problem that the oil pipe is required to have a high function, resulting in an increase in cost.

The present invention has been made in view of the above problems, and an object thereof is to improve maintenance workability.
An object of the present invention is to provide a two-cycle engine capable of simplifying the structure of oil piping and reducing costs.

[0006]

In order to achieve the above object, the invention according to claim 1 arranges an oil pump above the crankshaft of a two-cycle engine and below the top of the cylinder head, and The feature is that an oil tank is arranged above.

The invention according to claim 2 is characterized in that a fuel injection pump is arranged in the vicinity of the oil pump, and both are driven by a common drive mechanism.

Further, the invention according to claim 3 is characterized in that the oil pump and the fuel injection pump are arranged coaxially.

[0009]

According to the invention described in claim 1, since the oil pump is arranged above the engine, the workability of maintenance such as air removal and replacement of the oil pump is further enhanced.

Further, since the oil pump and the oil tank are both attached to the engine, the structure of the oil pipe connecting them is simplified, and relative movement (vibration) does not occur in the oil pipe. High performance is not required for the piping, and the cost can be reduced.

Further, since the oil tank is arranged above the oil pump, it is easy to remove air from the oil pipe.

According to the second aspect of the invention, the oil pump and the fuel injection pump are arranged close to each other, and both are driven by a common drive mechanism. According to the third aspect of the invention, the oil pump and the fuel Since the injection pump is coaxially arranged, it is possible to reduce the size and size of the engine and reduce the cost.

[0013]

An embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a vertical sectional view of a two-cycle engine according to the present invention, and FIG. 2 is a cutaway front view of a ship equipped with the two-cycle engine.

The two-cycle engine 1 according to the present embodiment is an inboard engine, which is housed in an engine room 51 formed in the center of a hull 50 as shown in FIG. That is, the two-cycle engine 1 includes a pair of left and right engine mounting beds 52 installed in an engine room 51.
A mount is supported by a vibration-proof rubber 53.

Further, as shown in FIG. 2, an oil pump 54 for circulating oil for lubricating various gear groups is attached to the lower portion of the engine 1.

Details of the structure of the two-cycle engine 1 according to the present invention will be described with reference to FIG.

The two-cycle engine 1 is a water-cooled two-cycle engine with in-line three cylinders, and its cylinder body 2
, Three cylinders 2a are arranged side by side in the direction perpendicular to the plane of FIG. A piston 3 is fitted in each cylinder 2a so as to be vertically slidable, and the piston 3 is connected to a crankshaft 4 arranged below the piston 3 in a direction perpendicular to the paper surface of FIG. 1 through a connecting rod 5. Has been done. The upper crankcase 2b integrally formed with the cylinder body 2
A crank chamber 7 is formed inside the lower crankcase 6 connected to the lower surface of the crank chamber 7.
The crankshaft 4 is rotatably supported and housed therein.

Further, the cylinder body 2 is formed with a scavenging port 8, a main exhaust port 9 and a plurality of sub-exhaust ports 10. The sub-exhaust port 10 communicates with the main exhaust port 9 and the communication thereof. A rotary variable valve 11 which is long in the direction perpendicular to the paper surface of FIG. 1 is rotatably provided in the section. The variable valve 11 constitutes a variable compression mechanism together with drive means and control means (not shown), and the variable compression mechanism is provided for the purpose of improving the startability and high-speed high-load performance of the two-cycle engine 1. ing.

Further, around the cylinder 2a of the cylinder body 2, a plurality of cooling jackets 12 to 12 which communicate with each other are provided.
15 is formed.

A two-division type cylinder head 17 is attached to the upper surface of the cylinder body 2, and the vortex chamber 1 communicating with the cylinder 2a is attached to the cylinder head 17.
8 is formed. Then, in the cylinder head 17, the injector 1 whose tip end faces the inside of the vortex chamber 18
9 and the glow plug 20 are screwed together.

On the other hand, the air introduction port 2 opening to the crank chamber 7 is provided in the lower portion of the cylinder body 2 facing each other.
1 and a communication port 22 are formed, and the air introduction port 21 is provided with a reed valve 23 that allows only air to flow toward the crank chamber 7. An intake manifold 24 is connected to the air introduction port 21 of each cylinder.

The crank chamber 7 of each cylinder is provided with the communication port 2
2 and the scavenging bypass passage 25 can communicate with each other, and the scavenging bypass passage 25 is provided with a scavenging valve 26 for each cylinder.

By the way, in this embodiment, an indirect cooling heat exchanger (hereinafter simply referred to as a heat exchanger) 27 for cooling the cooling water with seawater and an exhaust passage 28 are integrally formed. The cylinder body 2 is integrally bonded to the exhaust side wall.

By the way, the communication passage 2 is provided in the exhaust passage 28.
The main exhaust port 9 and the auxiliary exhaust port 10 of each cylinder communicate with each other via 9.

Further, the heat exchanger 27 includes the exhaust passage 2
The cooling jacket 30 formed around 8 and a large number of cooling pipes 31 that are long in the direction perpendicular to the paper surface of FIG. 1 are formed in the cooling jacket 30, and in the heat exchanger 27, The cooling jackets 12 to 15 and 3
The cooling water that has flowed through 0 to be used for cooling each part is cooled by the seawater flowing in the cooling pipe 31. The cooling pipe 31 in which seawater flows is made of a material having high corrosion resistance (for example, SUS).

The two-cycle engine 1 employs a dry sump system as a lubrication system,
As shown in FIG. 1, on the side opposite to the exhaust side (left side in FIG. 1),
An oil pump 32 is arranged above the crankshaft 4 and below the top of the cylinder head 17, and a fuel injection pump (not shown) is coaxially arranged behind the oil pump 32. The oil pump 32 differs from the oil pump 54 (see FIG. 2) in that the cylinder 2a
This is for circulating oil that lubricates the sliding surface with the piston 3 and the bearing portion of the crankshaft 4, and an air vent plug 33 is screwed to this.

The drive shaft 3 of the oil pump 32 is
A pulley 35 is attached to the end of the pulley 4.
An endless drive belt 37 is wound between the pulley 5 and the small diameter pulley 36 connected to the crankshaft 4.

An oil tank 38 is disposed directly above the oil pump 32 so as to be directly attached to the cylinder head 17 via an anti-vibration rubber (not shown). The oil tank 38 is disposed between the oil tank 38 and the oil pump 32. Is connected to an oil pipe 39 bent in an L shape.

When the two-cycle engine 1 is driven, the crankshaft 4 is rotated by the pulley 36 and the drive belt 3.
Drive shaft 34 of the oil pump 32 through the pulley 7 and the pulley 35.
And the oil pump 32 arranged coaxially and a fuel injection pump (not shown) are simultaneously driven.

In the above, according to the present embodiment, since the oil pump 32 is arranged above the two-cycle engine 1, the air vent plug 33 is operated to operate the oil pump 32.
The air can be easily removed, and maintenance such as replacement of the oil pump 32 can be performed with good workability.

Further, the oil pump 32 and the oil tank 38
Are both attached to the 2-cycle engine 1, and
The oil tank 38 is directly attached to the cylinder head 17 via a vibration-proof rubber (not shown).
The oil pipe 39 connecting the oil tank 38 with the oil tank 38 can be short, the structure thereof can be simplified, and relative movement (vibration) does not occur in the oil pipe 39. Therefore, the oil pipe 39 is required to have a high function. Instead, the cost can be reduced.

Further, the oil tank 38 is the oil pump 3
Since it is arranged above 2, the air in the oil pipe 39 can be easily removed.

Further, the oil pump 32 and the oil tank 3
Since 8 is arranged on the intake side (low temperature side) opposite to the high temperature exhaust side, the temperature rise of the oil is prevented, and the viscosity decrease of the oil due to the temperature rise does not occur, and a stable oil supply is provided. Proper lubrication is carried out by.

In addition, in this embodiment, the oil pump 32
Since the fuel injection pump and the fuel injection pump are arranged coaxially and both are driven by a common drive mechanism (pulleys 35, 36 and drive belt 37), the overall size and cost of the two-cycle engine 1 can be reduced.

Although an example in which the present invention is applied to an inboard motor has been described above, it is a matter of course that the present invention includes any other two-cycle engine having an oil pump and an oil tank as an application target. .

[0037]

As is apparent from the above description, according to the invention of claim 1, the oil pump is arranged above the crankshaft of the two-cycle engine and below the top of the cylinder head, and Since the oil tank is arranged above, the workability of maintenance such as air bleeding and replacement of the oil pump can be improved, the structure of the oil pipe can be simplified, and the cost can be reduced.

Further, according to the invention described in claim 2, the oil pump and the fuel injection pump are arranged close to each other, and both are driven by a common drive mechanism. According to the invention described in claim 3, the oil pump and the fuel Since the injection pump is coaxially arranged, the engine can be made smaller and more compact, and the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a two-stroke engine according to the present invention.

FIG. 2 is a cutaway front view of a ship equipped with a two-cycle engine according to the present invention.

[Explanation of symbols]

 1 2 Cycle Engine 4 Crank Shaft 17 Cylinder Head 32 Oil Pump 35, 36 Pulley (Drive Mechanism) 37 Drive Belt (Drive Mechanism) 38 Oil Tank

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Tatsuyuki Masuda Yamaha Motor Co., Ltd. 2500 Shinkai, Iwata, Shizuoka Prefecture

Claims (3)

[Claims] 1. A two-cycle engine, wherein an oil pump is arranged above the crankshaft and below the top of the cylinder head, and an oil tank is arranged above the oil pump. 2. The two-cycle engine according to claim 1, wherein a fuel injection pump is arranged near the oil pump, and both are driven by a common drive mechanism. 3. The two-stroke engine according to claim 2, wherein the oil pump and the fuel injection pump are coaxially arranged.