JPH1047055A - Wet liner type multi-cylinder engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve cooling performance by simplifying the cooling structure of the surroundings of a cylinder. SOLUTION: A wet liner type multicylinder engine is formed such that a part of the wall of a water jacket 8 consists of a cylinder liner 3 and the outer peripheral part of a cylinder liner 3 is mounted in a screwed-in state on a cylinder head 9. In this case, a water jacket 12 on the cylinder head side 9 side is extended to the surroundings of the screwing-in part (a mounting part) of the cylinder liner 3. Since the water jacket 12 on the cylinder head 9 side is extended to the surroundings of the screwing-in part of the cylinder liner 3, the water jackets 8 and 12 are formed throughout the whole range of the surroundings of the cylinder liner 3 and cooling performance of the cylinder for each piston is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a water jacket comprising a cylinder liner and a part of a wall of a water jacket.
The present invention relates to a wet liner type multi-cylinder engine in which an outer peripheral portion of an upper end of the cylinder liner is mounted on a cylinder head.

[0002]

2. Description of the Related Art In a water-cooled multi-cylinder engine, a so-called wet liner system in which a part of a wall of a water jacket is constituted by a cylinder liner is employed in order to reduce the pitch between bores of adjacent cylinders and to achieve compactness and compactness. Sometimes.

In an engine employing such a wet liner system, since a water jacket is formed around a cylinder liner, most of the combustion pressure in the cylinder is received by the cylinder liner itself. In particular, the piston is at top dead center (TDC) at the beginning of the combustion stroke.
In the early stage of descending past the cylinder liner, a high combustion pressure acts on the upper end of the cylinder liner, so an engine that screwed the outer periphery of the upper end of the cylinder liner to the cylinder head to receive the high combustion pressure with the cylinder head was developed. Proposed.

[0004]

However, in an engine employing a configuration in which the outer periphery of the upper end of the cylinder liner is mounted on the cylinder head as described above, the height of the cylinder block is relatively low. There is a problem that the height of the water jacket formed between the cylinder block and the cylinder liner is reduced, and the cooling performance around the cylinder is reduced.

Accordingly, it is an object of the present invention to provide a wet liner type multi-cylinder engine capable of improving the cooling performance around a cylinder.

In a conventional water-cooled multi-cylinder engine, a cooling water distribution main gallery for distributing cooling water to each cylinder in a cylinder block is provided separately from a water jacket formed in the cylinder block. As a result, the cooling structure of the cylinder block becomes complicated, which causes an increase in the weight of the engine.

Accordingly, it is an object of the present invention to provide a wet liner type multi-cylinder engine capable of simplifying a cooling structure around a cylinder and reducing the weight.

[0008]

According to a first aspect of the present invention, there is provided a water jacket having a cylinder liner, wherein a part of a wall of a water jacket is formed, and an outer peripheral portion of an upper end of the cylinder liner is attached to a cylinder head. In the wet liner type multi-cylinder engine mounted, the water jacket on the cylinder head side is formed to extend to around the mounting portion of the cylinder liner.

According to a second aspect of the present invention, in the first aspect of the invention, a water jacket is formed between the cylinder block and the cylinder liner, and a part of the water jacket is used for distributing cooling water. The main gallery is also used.

Therefore, according to the first aspect of the present invention, since the water jacket on the cylinder head side is formed so as to extend to around the mounting portion of the cylinder liner, the water jacket is formed over the entire area around the cylinder liner. As a result, the cooling performance of the cylinder of each cylinder is improved.

According to the second aspect of the present invention, since a part of the water jacket formed between the cylinder block and the cylinder liner also serves as a main gallery for distributing cooling water, the water jacket for distributing cooling water to the cylinder block is provided. There is no need to separately provide a main gallery, and the cooling structure of the cylinder block can be simplified to reduce the weight of the engine.

[0012]

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

FIG. 1 is a partial sectional view of an essential part of an in-line multi-cylinder engine according to the present invention, FIG. 2 is an enlarged detailed view of a portion A in FIG. 1, and FIG. 3 is a plan sectional view of the in-line multi-cylinder engine (C in FIG. 3). FIG. 4 is a sectional view taken along line BB of FIG.

In-line multi-cylinder engine 1 according to the present embodiment
Has a cylinder block 2 integrally cast with a lightweight A1 alloy, and a plurality of cylinders are arranged in the cylinder block 2 in a direction perpendicular to the plane of FIG. 1 (vertical direction in FIG. 2). Is mounted with a cylinder liner 3 made of an A1 alloy. A piston 4 is slidably fitted in each cylinder liner 3, and each piston 4 is connected to a crankshaft 6 via a connecting rod 5. That is, the small end of the connecting rod 5 is connected to the piston 4 by the piston pin 7, and the large end of the connecting rod 5 is connected to the crank pin 6 a of the crank shaft 6. The crankshaft 6 is arranged in a direction perpendicular to the plane of FIG.

The in-line multi-cylinder engine 1 according to the present embodiment employs a wet liner system. For each cylinder, the cylinder liner 3 is formed on the outer wall of the water jacket 8 where the cylinder liner 3 is formed. Make up part. By adopting such a wet liner system, the pitch between the bores of adjacent cylinders is shortened. Therefore, the overall length of the engine 1 (the length in the direction perpendicular to the paper surface of FIG. 1) is shortened to reduce its size and size. Can be planned.

In the present embodiment, a rib 2a is provided for each cylinder in the cylinder block 2 so as to protrude across the water jacket 8, and an intermediate height position of an outer peripheral portion of each cylinder liner 3 is set at the rib. Partially supported by 2a.

On the other hand, an upper part of each cylinder of the cylinder block 2 has a cylinder head 9 integrally cast of A1 alloy.
The cylinder head 9 is provided with an intake passage 10 and an exhaust passage 11 for each cylinder. Water jackets 12 and 13 are provided around the intake passage 10 and the exhaust passage 11, respectively. Is formed.
The intake passage 10 and the exhaust passage 11 are opened and closed at appropriate timing by an intake valve and an exhaust valve (not shown), whereby required gas exchange is performed in each cylinder.

By the way, the cylinder head 9 of the in-line multi-cylinder engine 1 according to the present embodiment has a lower end surface (joint surface with the cylinder block 2) having a height H shown in FIG. A screw recess 9a having the same diameter as the cylinder bore is formed in the extension of the block 2 and a female screw 9 is formed on the inner periphery of the recess 9a.
a-1 (see FIG. 2) is engraved.

The cylinder liner 3 has an upper end protruding above the upper surface of the cylinder block 2, and the outer periphery of the protruding portion is the inner periphery of the recess 9 a formed in the cylinder head 9. It is screwed to the part.

That is, a male screw 3a (see FIG. 2) is engraved on the outer peripheral portion of the upper end of the cylinder liner 3, and the male screw 3a is engraved on the inner peripheral portion of the concave portion 9a on the cylinder head 9 side. The cylinder liner 3 is assembled to the cylinder head 9 by being screwed onto the female screw 9a-1, and a gasket ring 14 made of Cu is interposed between the upper end surface of the cylinder liner 3 and the cylinder head 9. ing. Further, as shown in FIG. 2, a 0 ring 15 for sealing is provided below the screw portion of the cylinder liner 3 to the cylinder head 9 and between the cylinder liner 3 and the cylinder block 2. It is interposed. As shown in detail in FIG. 2, a female screw 9a-1 formed on the cylinder head 9 side and a male screw 3a formed on the cylinder liner 3 side are saw-tooth screws combining a square screw and a triangular screw. It is composed of

In this embodiment, the outer periphery of the upper end of the cylinder liner 3 is screwed to the cylinder head 9.
As shown in FIG. 5, the outer peripheral portion of the upper end of the cylinder liner 3 may be press-fitted into the recess 9a of the cylinder head 9, and in this case, the fitting portion a of the cylinder liner 3 with the cylinder head 9 is brazed. In addition, as a method of attaching the cylinder liner 3 to the cylinder head 9, any method such as caulking or bonding can be adopted.

In the in-line multi-cylinder engine 1 according to the present embodiment, as shown in FIG. 1, the water jacket 12 on the cylinder head 9 side faces the mating side of the cylinder head 9 with the cylinder block 2. The threaded portion of the cylinder liner 3 is formed to extend to the threaded portion of the cylinder liner 3, and the threaded portion of the cylinder liner 3 is surrounded by the water jacket 12. The outer periphery of a portion of the cylinder liner 3 other than the screwed portion to the cylinder head 9 is surrounded by the water jacket 8 formed between the cylinder liner 3 and the cylinder block 2.

Accordingly, the water jacket 8 formed on the cylinder block 2 side and the water jacket 1 formed on the cylinder head 9 side surround the cylinder liner 3.
2, the entire area is surrounded by the cylinders. The surroundings of the cylinders of each cylinder are efficiently cooled by the cooling water flowing through the water jackets 8, 12, and the cooling performance of the engine 1 is enhanced.

On the other hand, as shown in FIGS. 3 and 4, a partition 2b provided between adjacent cylinders of the cylinder block 2 is provided.
Are formed with substantially rectangular water holes 2b-1 and 2b-2, and the exhaust side (FIG. 3) of the water jacket 8 is formed.
The cooling water passage 8a (on the right side of FIG. 3) is formed wider than the cooling water passage 8b on the intake side (left side in FIG. 3), and is communicated with the water passage hole 2b-1 formed in the partition wall 2b to form a cylinder block. 2 also serves as a cooling water distribution main gallery extending in the length direction (vertical direction in FIG. 3).

The cooling water supplied to the cylinder block 2 by the cooling water pump 16 is distributed from the cooling water passage 8a to each cylinder and is used for cooling around the cylinder of each cylinder. In the present embodiment, since the cooling water passage 8a constituting a part of the water jacket 8 also serves as a cooling water distribution main gallery, it is not necessary to separately provide a cooling water main gallery in the cylinder block 2, and the cooling of the cylinder block 2 is prevented. The structure is simplified, and the weight of the engine 1 is reduced.

By the way, as shown in FIG. 4, the combustion pressure P for each cylinder shows a maximum value Pmax after passing through the top dead center (TDC), and thereafter gradually decreases as the crank angle θ increases. In the state shown in FIG. 1 in which the piston 4 is lowered past the top dead center, a high combustion pressure P acts on the upper end of the cylinder liner 3.

However, in this embodiment, since the outer periphery of the upper end of the cylinder liner 3 is screwed to the cylinder head 9, the high combustion pressure P is finally received by the cylinder head 9 via the cylinder liner 3. The load on the cylinder liner 3 is reduced by that much.

In this embodiment, an example in which the present invention is applied particularly to an in-line multi-cylinder engine has been described. However, the present invention is similarly applicable to any other multi-cylinder engine employing a wet liner system. Can be applied to

[0029]

As is apparent from the above description, claim 1
According to the described invention, since the water jacket on the cylinder head side is formed so as to extend around the mounting of the cylinder liner, the water jacket is formed over the entire range around the cylinder liner, and the cylinder of each cylinder is formed. This has the effect of improving the cooling performance of the device.

According to the second aspect of the present invention, a part of the water jacket formed between the cylinder block and the cylinder liner also serves as a main gallery for distributing cooling water. There is no need to separately provide a main gallery, and the effect of simplifying the cooling structure of the cylinder block and reducing the weight of the engine can be obtained.

[Brief description of the drawings]

FIG. 1 is a partial sectional view of a main part of an in-line multi-cylinder engine according to the present invention.

FIG. 2 is an enlarged detail view of a portion A in FIG. 1;

FIG. 3 is a plan sectional view (a sectional view taken along line CC in FIG. 3) of the in-line multi-cylinder engine according to the present invention;

FIG. 4 is a sectional view taken along line BB of FIG. 3;

FIG. 5 is a view similar to FIG. 4, showing a modified example of a method of mounting a cylinder liner on a cylinder head.

FIG. 6 is a diagram showing a change in a combustion pressure P with respect to a crank angle θ.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Wet liner type in-line multi-cylinder engine 2 Cylinder block 3 Cylinder liner 8 Water jacket 8a Main gallery for cooling water distribution 9 Cylinder head 12 Water jacket

Claims (2)

[Claims] 1. A wet liner type multi-cylinder engine in which a cylinder liner forms a part of a wall of a water jacket and an outer peripheral portion of an upper end of the cylinder liner is mounted on a cylinder head. A wet liner-type multi-cylinder engine, which is formed so as to extend to around the mounting portion of the cylinder liner. 2. A water jacket is formed between the cylinder block and the cylinder liner on the cylinder block side.
A wet liner type multi-cylinder engine, wherein a part of the water jacket is also used as a main gallery for distributing cooling water.