JP2719854B2 - Cylinder liner cooling structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylinder liner cooling structure for a multi-cylinder engine.

[0002]

2. Description of the Related Art Recently, a cooling structure of a cylinder liner, in which a coolant is supplied to a groove provided in one or both of an outer peripheral surface of a cylinder liner and an inner peripheral surface of a bore portion of a cylinder block, has attracted attention. This is because it is easier to control the cooling according to the position of the cylinder liner than in a jacket-type cooling structure that has been used for a long time.

[0003] In order to realize cooling in accordance with each part of the cylinder liner in the axial direction, for example, Japanese Utility Model Laid-Open No. 63-168
No. 242 proposes a cylinder liner having a plurality of annular groove groups formed on an outer peripheral surface.

[0004] However, in a multi-cylinder engine,
When this type of grooved liner is used, the wall temperature of the cylinder liner facing the combustion chamber is about 160 ° C. in the thrust-anti-thrust direction part, and about 190 ° C. in the crankshaft direction part. It turned out that it could not be cooled sufficiently. This temperature difference in the circumferential direction is extremely large in the upper part of the cylinder liner.

In order to solve the above problem, Japanese Patent Laid-Open No.
Japanese Patent No.-78517 proposes a cylinder liner in which the outer peripheral surface of the cylinder liner is cylindrical, and the groove bottom of the circumferential groove has an elliptical shape whose major axis is in the crankshaft direction and whose minor axis is in the thrust-anti-thrust direction. The flow rate of the cooling fluid flowing in the circumferential groove of the cylinder liner is large at a portion in the crankshaft direction, and is characterized in that the cooling capacity at that portion is large.

[0006]

However, in this type of cylinder liner, since the wall thickness is not uniform in the circumferential direction, the roundness of the inner peripheral surface of the cylinder liner is likely to be reduced, and the circumferential groove processing is performed. However, there are two problems that require the turning of the cam and low productivity.

[0007] The present invention has been made in view of the above points,
It is an object of the present invention to provide a cylinder liner cooling structure that can make the temperature in the circumferential direction of the liner uniform, and in which the roundness of the inner peripheral surface of the liner is hardly reduced and the production is easy.

[0008]

SUMMARY OF THE INVENTION According to the present invention, each cylinder bore of a cylinder block of a multi-cylinder engine is provided with:
In the cooling structure of a cylinder liner in which a plurality of annular grooves and a plurality of vertical grooves connected thereto are formed on an outer peripheral surface, and a coolant is circulated in the grooves, an inner peripheral surface of the cylinder liner, The outer peripheral surface and the annular groove bottom form a concentric cylindrical surface, and a ring whose cross-sectional area changes in the circumferential direction is provided in the annular groove of this liner. It is characterized in that the portion is mounted so as to be a portion in the direction of the crankshaft, and the sectional area of the coolant passage of the annular groove is changed.

Then, a plurality of rings may be connected to each other by a vertical connecting member arranged in the vertical groove.

[0010]

In the cylinder liner of the present invention, the inner peripheral surface, the outer peripheral surface, and the bottom surface of the annular groove form a concentric cylindrical surface, so that the liner thickness is uniform in the circumferential direction and the roundness of the inner peripheral surface is not easily reduced. ,
Also, since no cam turning is required, productivity is high.

A ring whose cross-sectional area changes in the circumferential direction can be manufactured by using a piston ring processing technique, and is easier than processing an elliptical groove in a cylinder liner.

When the ring is mounted on the annular groove such that the portion having a small cross-sectional area is the thrust-anti-thrust direction portion and the portion having a large cross-sectional area is the portion in the crankshaft direction, the cross-sectional area of the coolant passage in the annular groove portion is increased. Is large in the thrust-anti-thrust direction portion and is small in the crankshaft direction portion. For this reason, the flow rate of the coolant is large in the portion in the crankshaft direction and small in the portion in the thrust-anti-thrust direction, so that the cooling capacity in the portion in the crankshaft direction is increased and the temperature in the circumferential direction of the liner can be made uniform.

[0013]

EXAMPLE In an in-line four-cylinder oil-cooled gasoline engine, a coolant groove was formed on the outer peripheral surface of a cylinder liner. That is, in FIG. 2, the cylinder liner 1 is provided with a flange 2 at an upper end, and 18 annular grooves 4 are formed on the outer peripheral surface 3 of the liner below the flange 2 at intervals in the axial direction. These annular grooves 4 are divided into three annular groove groups.

The three annular groove groups are a first annular groove group 4A from the first annular groove 4 to the third annular groove 4 on the upper end of the liner, and a fourth annular groove 4 to the ninth annular groove. A second annular groove group 4B up to the annular groove 4, and a third annular groove group 4C from the tenth annular groove 4 to the last eighteenth annular groove 4.

In the first annular groove group 4A, two vertical grooves 5 and 6 for connecting the annular grooves 4 to each other are formed at two positions separated by 180 degrees in the liner circumferential direction. The groove 5 forms the inlet for the coolant and the other longitudinal groove 6 forms the outlet for the coolant.

Similarly, in the second annular groove group 4B, two vertical grooves for communicating the annular grooves 4 with each other at the same two positions in the circumferential direction as the longitudinal grooves 5, 6 of the first annular groove group 4A. Directional grooves 7 and 8 are formed, and the vertical groove 7 located on the coolant outlet side of the first annular groove group 4A serves as a coolant inlet, and the other vertical groove 8 serves as a coolant outlet.

Similarly, the third annular groove group 4C has two annular grooves 4 communicating with the longitudinal grooves 7, 8 of the second annular groove group 4B at the same two positions in the circumferential direction. Vertical grooves 9 and 10 are formed, a vertical groove 9 located on the coolant outlet side of the second annular groove group 4B forms a coolant inlet, and the other vertical groove 10 forms a coolant outlet. Eggplant

The vertical grooves 6 forming the outlet of the cooling liquid of the first annular groove group 4A and the vertical grooves 7 forming the inlet of the cooling liquid of the second annular groove group 4B are formed by the vertical grooves 6. , 7 are connected in series by a longitudinal groove 11 provided at the same position in the circumferential direction.

Similarly, the vertical grooves 8 forming the outlet of the coolant in the second annular groove group 4B and the vertical grooves 9 forming the inlet of the coolant in the third annular groove group 4C are formed by these vertical grooves. Direction grooves 8, 9
Longitudinal groove 12 provided at the same position in the circumferential direction
Are connected in series.

A discharge groove is formed below the liner outer peripheral surface 3. That is, on the outer peripheral surface 3 of the liner 1, a longitudinal groove 13 connected to the lower end of the longitudinal groove 10 serving as an outlet of the third annular groove group 4C and disposed on an extension thereof, and an annular groove 14 connected to the lower end thereof And a vertical groove 15 connected to the upper end thereof and extending to the lower end of the liner 1. Two longitudinal grooves 15 extending to the lower end of the liner are provided, and are arranged at positions 180 degrees apart from each other in the circumferential direction.

These discharge grooves 13, 14, 15
Is formed to use cooling oil as a cooling liquid and discharge it to an oil pan.For example, when using cooling water as a cooling liquid, the cooling water is discharged to a discharge path provided in a cylinder block. Configure to spill. Of course, the cooling oil may also be configured to flow out to the discharge path of the cylinder block.

The dimensions such as the inner and outer diameters of the cylinder liner 1 are shown below. Inner diameter: 85 mm Outer diameter: 94 mm Annular groove width: 3 mm Annular groove depth: 2 mm Vertical groove width: 20 mm Vertical groove depth: 2 mm The inner peripheral surface, outer peripheral surface, and annular groove bottom of this cylinder liner 1 are concentric. It has a cylindrical surface.

The cylinder liner 1 is fitted into each bore of the cylinder block 16 (see FIG. 3).
The following rings are mounted on the three annular grooves 4 of the annular groove group 4A.

The ring 17 (see FIG. 1) is a ring having a rectangular cross section with an abutment, and is arranged in the annular groove 4 while being compressed and pressed against the inner peripheral surface 18 of the bore of the cylinder block 16. The outer periphery of the ring 17 is a perfect circle in the mounted state, but the inner periphery is an elliptical shape. These dimensions are shown below. Outer diameter (mounting state): 94 mm Inner diameter long axis length: 93 mm Inner diameter short axis length: 92 mm Width: 3 mm Aperture gap (free state): 20 mm The shaft is arranged so as to be in the crankshaft direction.

As described above, in the first annular groove group 4A, the space defined by the annular groove 4 and the inner peripheral surface 19 of the ring 17 forms the coolant passage 20, and the sectional area of the coolant passage 20 is The directions are not the same, but are large in the thrust-anti-thrust direction part (see FIG. 4) and small in the crankshaft part (see FIG. 5). And the second annular groove group 4B
In the third annular groove group 4C, the space defined by the annular groove 4 and the inner peripheral surface 18 of the bore of the cylinder block 16 forms a coolant passage, and the sectional area of the coolant passage is the same in the circumferential direction. .

The rotation of the ring 17 may be appropriately stopped by a means for preventing the rotation of the piston ring on the piston of a two-stroke engine having an intake / exhaust port. For example, a pin is punched in the radial direction on the bottom surface of the annular groove 4 of the cylinder liner 1, or a pin is punched in one of the upper and lower surfaces of the annular groove 4 in the axial direction. It is only necessary to provide a notch portion that can be fitted in the ring.

Preferably, the abutment position of the ring 17 is adjusted to the vertical groove position.

The flow of the cooling oil will be described below. The cooling oil flows through a cooling oil supply passage provided in the cylinder block 16.
The cooling oil that has flowed into the longitudinal groove 5 that forms the inlet of the first annular groove group 4A of the cylinder liner 1 passes through the coolant passage 20 defined by the annular groove 4 and the ring 17 of the first annular groove group 4A.
After flowing to the opposite side, it flows from the vertical groove 6 forming the outlet of the first annular groove group 4A to the vertical groove 7 forming the inlet of the second annular groove group 4B.

Then, the coolant flows through the coolant passage defined by the annular groove 4 of the second annular groove group 4B and the inner peripheral surface 18 of the bore of the cylinder block 16 to the opposite side by 180 degrees, and the second annular groove group 4B from the vertical groove 8 to the third annular groove group 4
C flows into the longitudinal groove 9 forming the entrance of C.

Then, the coolant flows through the coolant passage defined by the annular groove 4 of the third annular groove group 4C and the inner peripheral surface 18 of the bore of the cylinder block 16 to the opposite side by 180 degrees, and the third annular groove group 4C enters the longitudinal groove 13 continuous from the longitudinal groove 10 forming the outlet, flows into the annular groove 14, flows in the annular groove 14 in the circumferential direction, and passes through the lowermost two longitudinal grooves 15 After falling on the main shaft of the crankshaft, it flows down to an oil pan (not shown).

In the above case, three annular groove groups 4A, 4B,
The total cross-sectional area of the annular groove 4 in 4C becomes smaller toward the upper part, and the flow velocity of the cooling oil flowing through each of the annular groove groups 4A, 4B, 4C becomes larger in the upper annular groove group. Therefore, the heat transfer coefficient of the cooling oil increases as it goes to the upper part of the liner, the cooling capacity increases, and appropriate cooling corresponding to the temperature gradient in the liner axial direction is performed.

Further, according to the present invention, in the first annular groove group 4A, the cross-sectional area of the coolant passage 20 changes in the circumferential direction, and is large in the thrust-anti-thrust direction portion, and is large in the crankshaft direction portion. Therefore, the flow rate of the cooling oil is small in the thrust-anti-thrust direction part and is large in the crankshaft direction part. Therefore, the cooling capacity of the portion in the crankshaft direction becomes larger than the cooling capacity of the portion in the thrust-anti-thrust direction, and the temperature in the circumferential direction of the liner 1 can be made uniform.

The in-line four-cylinder oil-cooled gasoline engine was operated under the following conditions, and the liner wall temperature of the cylinder liner 1 relative to the combustion chamber was measured at different circumferential positions. Engine operating conditions Rotation speed: 5400 rpm Load: 4/4 Cooling oil flow rate 20 l / min Cooling oil temperature (cylinder block inlet) 90 ° C. The wall temperature of the cylinder liner 1 was as follows. Crankshaft direction section 180 ° C. Thrust-anti-thrust direction section 170 ° C. For comparison, a conventional case without using a ring was as follows. Crankshaft section 190 ° C Thrust-anti-thrust section 160 ° C

As shown in FIG. 6, when the cross-sectional shape of the ring 17 is formed into a keystone shape in which the inner peripheral surface width is smaller than the outer peripheral surface width, the coolant flows between the ring inner peripheral surface 19 and the annular groove 4. In addition, since the gas flows also between the ring upper and lower surfaces 21 and 22 and the annular groove 4, the heat transfer area increases, which is advantageous.

Further, in the above description, the outer ring 17 that generates a force to stretch outward in the mounted state is shown, but an inner ring can be used as shown in FIG. In this case, mounting of the cylinder liner 1 on the bore of the cylinder block 16 is easier than the outer ring. In FIG. 7, the corner of the annular groove 4 of the liner 1 on the outer peripheral surface 3 side is chamfered to form a slope 23. The ring 17 has a keystone cross-sectional shape, and the outer ends of the upper and lower surfaces 21 and 22 are locked to the corner slopes 23 of the annular groove 4 with an inward elastic force.

As shown in FIG. 8, the abutment ends of the three rings 17 may be connected to each other by a vertical connecting member 24. The vertical connection members 24 are provided at both ends of the abutment, but may be provided at other locations. In this flow path cross-sectional area adjusting member, the ring 17 is disposed in the annular groove 4 and the vertical connecting member 24 is disposed in the vertical groove.

Further, in the above description, the annular grooves are divided into three annular grooves, but they may be divided into two or more annular grooves. The configuration of the coolant groove to which the present invention is applied is not limited to the above-described configuration of the annular groove group, but may be any as long as a plurality of annular grooves and a vertical groove connected to the annular grooves are provided.

In the above description, the ring is mounted on the annular groove on the upper part of the liner. However, the ring may be mounted on the annular groove below the ring.

In the above example, the cross-sectional shape of the groove is rectangular, but there is no particular limitation, and the groove may be V-shaped or semi-circular. However, in order to increase the heat transfer area, a rectangle or square is preferred. Also, the cross-sectional shape of the ring is not particularly limited.

[0040]

As described above, according to the present invention, in a multi-cylinder engine, the cooling capacity in the direction of the crankshaft is high, and the temperature in the circumferential direction of the cylinder liner can be made uniform. Since the thickness of the cylinder liner is uniform, the roundness of the inner circumference hardly decreases, and the productivity is excellent.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a portion where a ring is mounted in a cylinder block in which a cylinder liner is fitted.

FIG. 2 is a development view showing a part of an outer peripheral surface of a cylinder liner.

FIG. 3 is a plan view of a cylinder block fitted with a cylinder liner.

FIG. 4 is a vertical sectional view of a thrust-anti-thrust direction portion of a portion where a ring is mounted in a cylinder block fitted with a cylinder liner.

FIG. 5 is a vertical cross-sectional view of a portion of the cylinder block in which the cylinder liner is fitted, on which a ring is mounted, in the crankshaft direction.

FIG. 6 is a longitudinal sectional view of a portion where a ring having a keystone sectional shape is mounted in a cylinder block in which a cylinder liner is fitted.

FIG. 7 is a vertical cross-sectional view of a portion where a lining ring is mounted in a cylinder block fitted with a cylinder liner.

FIG. 8 is a perspective view showing a flow path cross-sectional area adjusting member in which a plurality of rings are connected by a vertical connecting member.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylinder liner 2 Flange 3 Liner outer peripheral surface 4 Annular groove 4A First annular groove group 4B Second annular groove group 4C Third annular groove group 5, 6, 7, 8, 9, 10, 11, 12 Vertical groove 13 , 14, 15 Discharge groove 16 Cylinder block 17 Ring 18 Bore inner peripheral surface 19 Ring inner peripheral surface 20 Coolant passage 21, 22 Ring upper / lower surface 23 Corner slope 24 Vertical connection member T Thrust position AT Anti-thrust position F Front position R rear position

Claims (2)

(57) [Claims] 1. A cylinder liner having an annular groove and a plurality of longitudinal grooves connected to the annular groove formed on an outer peripheral surface of each cylinder bore of a cylinder block of a multi-cylinder engine. In the cooling structure of the cylinder liner to be circulated, the inner peripheral surface, the outer peripheral surface, and the annular groove bottom surface of the cylinder liner form a concentric cylindrical surface, and the annular groove portion of the liner has a ring whose cross-sectional area changes depending on the circumferential direction. Cylinder characterized in that a portion having a small cross-sectional area is a thrust-anti-thrust direction portion and a portion having a large cross-sectional area is a portion in a crankshaft direction, and a cross-sectional area of a coolant passage in the annular groove portion is changed. Liner cooling structure. 2. A cylinder liner having an annular groove and a plurality of longitudinal grooves connected to the annular groove formed on an outer peripheral surface of each cylinder bore of a cylinder block of a multi-cylinder engine. In the cooling structure of the cylinder liner to be circulated, the inner peripheral surface, the outer peripheral surface, and the bottom surface of the annular groove of the cylinder liner form a concentric cylindrical surface, and the sectional area of the annular groove and the longitudinal groove portion of the liner varies depending on the circumferential direction. A flow path cross-sectional area adjusting member in which a plurality of rings are connected to each other by a vertical connecting member, such that a portion having a small cross-sectional area of the ring is a thrust-anti-thrust direction portion, and a portion having a large cross-sectional area is a crankshaft direction portion. Wherein the sectional area of the coolant passage in the annular groove is changed.