JPH0530443U - Cylinder liner cooling structure - Google Patents

Abstract

(57) [Summary] [Purpose] To make the temperature uniform in the circumferential direction of the cylinder liner. A cylinder liner 1 having a plurality of annular grooves 4 and a longitudinal groove connected to the annular grooves 4 on an outer peripheral surface 3 is fitted into each bore of a cylinder block 16 of a multi-cylinder engine. And, in the crankshaft direction portion of the annular groove 4 in the upper part of the liner, the uneven surface 1 which makes the flow of the cooling liquid a turbulent flow and increases the cooling capacity is provided.
9 and 20 are formed.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a cooling structure for a cylinder liner in a multi-cylinder engine.

[0002]

[Prior Art]

 Recently, attention has been paid to a cooling structure for a cylinder liner in which a cooling liquid is caused to flow in a groove provided in one or both of the outer peripheral surface of the cylinder liner and the inner peripheral surface of the bore portion of the cylinder block. This is because it is easier to control the cooling capacity according to each part of the cylinder liner compared to the conventional jacket type cooling structure.

In order to control the cooling state according to each axial portion of the cylinder liner, for example, a cylinder liner described in Japanese Utility Model Publication No. 3-29560 has an annular groove on the outer peripheral surface and a longitudinal direction. A groove is formed, and the cooling zone on the outer peripheral surface is divided into a plurality of stages in the axial direction.

However, when a grooved cylinder liner of this type is used in a multi-cylinder engine, the temperature distribution in the axial direction can be controlled, but the crankshaft axial portion is not sufficiently cooled, and this portion has thrust-reaction. The temperature tends to be higher than in the thrust direction.

In order to solve the above-mentioned problem, in JP-A-3-78517, the outer peripheral surface of a cylinder liner is made cylindrical, and the groove bottom of the circumferential groove is long in the crank axis direction and short in the thrust-anti-thrust direction. An elliptic cylinder liner having a shaft has been proposed. The flow velocity of the cooling liquid flowing in the circumferential groove of the cylinder liner becomes large in the crankshaft direction portion, and the cooling capacity at that portion is large.

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 decrease, and a cam turning is required for the circumferential groove machining. However, there were two problems of low productivity.

[0007]

[Problems to be solved by the device]

 In Japanese Patent Application No. 3-143922 made in view of the above point, a turbulent flow forming member is arranged in a cooling liquid passage groove in the crankshaft direction to make the flow of the cooling liquid turbulent in the crankshaft direction portion, and the thrust is generated. -It is proposed that the heat transfer coefficient be changed in the circumferential direction part by making a laminar flow state in the anti-thrust direction part, thereby further cooling the crankshaft direction part. However, this has the problem of increasing the number of parts.

An object of the present invention is to provide a cooling structure for a cylinder liner, which can make the temperature in the circumferential direction of the cylinder liner uniform and which is easy to machine and assemble.

[0009]

[Means for Solving the Problems]

 According to the structure of the present invention, a groove is formed in one or both of the outer peripheral surface of the cylinder liner and the inner peripheral surface of the bore portion of the cylinder block, and the cooling liquid flows through the groove in the cylinder liner cooling structure for a multi-cylinder engine. It is characterized in that a concavo-convex surface is formed in the crankshaft direction portion of which the flow state of the cooling liquid is turbulent.

[0010]

[Action]

 Since the cooling fluid of the cylinder liner of the present invention flows through the groove-shaped cooling fluid passage at a high speed, it has a higher cooling capacity than the jacket method. However, since the size of the groove is small, the flow of cooling liquid flowing in the passage is laminar when the wall surface of the groove is smooth. The uneven surface formed in the crankshaft direction portion of the cooling liquid groove disturbs the flow of the cooling liquid and changes the flow of this part into a turbulent state, thereby increasing the heat transfer coefficient of the cooling liquid.

In addition to the increase in the heat transfer coefficient of the cooling liquid due to the turbulent flow, the increase in the heat transfer area due to the uneven surface increases the heat transfer amount in the crankshaft direction portion. As a result, the cylinder liner of the present invention has high thermal uniformity in the circumferential direction.

[0012]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. 1 to 3, a cylinder liner 1 is provided with a collar portion 2 at its upper end, and 18 annular grooves 4 are formed on the outer peripheral surface 3 of the liner below the collar portion 2 at axial intervals. .. Then, these annular grooves 4 are divided into three annular groove groups.

The three annular groove groups include a first annular groove group 4A from a first annular groove 4 to a fourth annular groove 4 on the upper end side of the liner, and a fifth annular groove 4 to a tenth annular groove. The second annular groove group 4B up to the thirteenth annular groove 4 and the third annular groove group 4C from the eleventh annular groove 4 to the final eighteenth annular groove 4 are formed.

In the first annular groove group 4A, two longitudinal grooves 5 and 6 for communicating the annular grooves 4 with each other are formed at two positions 180 degrees apart from each other in the liner circumferential direction. The groove 5 serves as an inlet for the cooling liquid, and the other longitudinal groove 6 serves as an outlet for the cooling liquid.

Similarly, in the second annular groove group 4B, two longitudinal grooves 5 and 6 of the first annular groove group 4A are provided at the same two positions in the circumferential direction so that the two annular grooves 4 communicate with each other. Directional grooves 7 and 8 are formed, and the longitudinal groove 7 located on the cooling liquid outlet side of the first annular groove group 4A serves as the cooling liquid inlet, and the other longitudinal groove 8 serves as the cooling liquid outlet.

Similarly, in the third annular groove group 4C, two annular grooves 4 are made to communicate with each other at two circumferentially identical positions as the longitudinal grooves 7 and 8 of the second annular groove group 4B. Vertical grooves 9 and 10 are formed, the vertical groove 9 located on the cooling liquid outlet side of the second annular groove group 4B serves as the cooling liquid inlet, and the other vertical groove 10 serves as the cooling liquid outlet. Eggplant

The vertical grooves 6 that form the outlet of the cooling liquid of the first annular groove group 4A and the vertical grooves 7 that form the inlet of the cooling liquid of the second annular groove group 4B correspond to these 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 groove 8 serving as the coolant outlet of the second annular groove group 4B and the vertical groove 9 serving as the coolant inlet of the third annular groove group 4C have The longitudinal grooves 8 and 9 are connected in series by a longitudinal groove 12 provided at the same position in the circumferential direction.

A discharge groove is formed in the lower portion of the outer peripheral surface 3 of the liner. That is, on the outer peripheral surface 3 of the liner 1, a vertical groove 13 connected to the lower end of the vertical groove 10 forming the outlet of the third annular groove group 4C and arranged on the extension line thereof, and an annular groove connected to the lower end thereof. 14 and a longitudinal groove 15 having an upper end connected thereto and extending to the lower end of the liner 1. Further, two vertical grooves 15 extending to the lower end of the liner are provided, and they are arranged at positions 180 degrees apart from each other in the circumferential direction.

The discharge grooves 13, 14, 15 are formed to use cooling oil as a cooling liquid and discharge the cooling oil to an oil pan. For example, cooling water is used as the cooling liquid. In this case, the cooling water is designed to flow out to the discharge passage provided in the cylinder block. Of course, cooling oil may also be configured to flow to the discharge passage of the cylinder block.

Further, in the present embodiment, on the groove bottom surfaces and groove side surfaces of the four annular grooves 4 of the first annular groove group 4A facing the combustion chamber, ± 15 in the circumferential direction with the crank axis direction as the center. The uneven surfaces 19 and 20 are formed over a range of degrees. The uneven surface 19 formed on the bottom surface of the groove is an uneven surface having a plurality of conical holes formed on the bottom surface of the groove, and the uneven surface 20 formed on the side surface of the groove has a plurality of arc-shaped concave surfaces formed on the side surface of the groove. It has an uneven surface. These concave-convex surfaces 19 and 20 are formed on the first annular groove group 4A facing the combustion chamber over a range of ± 15 degrees in the circumferential direction around the crank axis direction before the grooves are formed on the outer peripheral surface of the cylinder liner 1. Using a drill with a diameter slightly larger than the width of the annular groove 4 at the four annular groove 4 positions from the top, drill a large number of holes in the range that does not penetrate the liner thickness radially from the outer circumference. It is formed by subjecting the outer peripheral surface to a groove processing after that.

The main dimensions of this cylinder liner 1 are as follows. Cylinder liner inner diameter: 80 mm Outer diameter: 88 mm Annular groove width: 2.5 mm Depth: 2.0 mm Drill hole diameter: 3.0 mm Number of holes: 5

The cylinder liner 1 is fitted in each of the bores of the cylinder block 16 (see FIG. 4), and the space defined by the inner peripheral surface 17 of the bore of the cylinder block 16 and the grooves 4 to 15 is the cooling liquid. It forms the passage 18 (see FIG. 1).

The flow of the cooling oil will be described below. Through the cooling oil supply passage provided in the cylinder block 16, the cooling oil flows into the longitudinal groove 5 that forms the inlet of the first annular groove group 4A of the cylinder liner 1. The cooling oil flows through the annular groove 4 of the first annular groove group 4A toward the opposite side by 180 degrees, and enters the second annular groove group 4B from the longitudinal groove 6 that forms the outlet of the first annular groove group 4A. It flows into the longitudinal groove 7 forming the mouth.

Then, it flows through the annular groove 4 of the second annular groove group 4B toward the opposite side by 180 degrees, from the longitudinal groove 8 forming the outlet of the second annular groove group 4B to the inlet of the third annular groove group 4C. Flows into the vertical groove 9 which forms

Then, it flows in the annular groove 4 of the third annular groove group 4C toward the opposite side by 180 degrees, and changes from the vertical groove 10 forming the outlet of the third annular groove group 4C to the vertical groove 13 continuous thereto. It enters, flows into the annular groove 14, flows in the annular groove 14 in the circumferential direction, falls from the two vertical grooves 15 at the lowermost end onto the main shaft of the crankshaft (not shown), and then flows down to the oil pan (not shown). .

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

Although the flow state of the cooling oil is laminar in the thrust-anti-thrust direction portion, in the present embodiment, in the first annular groove group 4A, cooling is applied to the annular groove 4 in the crankshaft direction. Since the concavo-convex surfaces 19 and 20 that make the flow of the liquid turbulent are formed, the flow state of the cooling oil in the crankshaft axial direction becomes turbulent. Therefore, the heat transfer coefficient between the cooling oil and the cylinder liner 1 becomes larger in the crankshaft direction part than in the thrust-anti-thrust direction part, and the heat transfer area also increases due to the uneven surfaces 19 and 20, so that the crankshaft direction part is As a result of further cooling, the temperature in the circumferential direction of the cylinder liner 1 becomes uniform.

A cylinder liner 1 of the present invention having an annular groove 4 in which uneven surfaces 19 and 20 are formed, a conventional cylinder liner having an annular groove in which uneven surfaces are not formed, and a conventional cylinder cooling system of a jacket cooling system. The cylinder liner and the inline 4-cylinder oil-cooled gasoline engine (displacement: 1.6 liters) were installed and operated under the test conditions of 6000 rpm and 4/4 load, and at the top dead center position of the top ring. The wall temperature in the crankshaft direction part of the cylinder liner and the wall temperature in the thrust-anti-thrust direction part were measured. The results are as follows.

(1) Cylinder liner of the present invention having an annular groove having an uneven surface Crankshaft direction part: 175 ° C Thrust-anti-thrust direction part: 160 ° C Crankshaft direction part and thrust-anti-thrust direction part Temperature difference: 15 ° C (2) Conventional cylinder liner having an annular groove with no uneven surface Crankshaft direction part: 185 ° C Thrust-anti-thrust direction part: 160 ° C Crankshaft direction part and thrust-anti-thrust direction part Temperature difference: 25 ° C (3) Conventional cylinder liner with jacket cooling system Crankshaft direction part: 200 ° C Thrust-anti-thrust direction part: 150 ° C Temperature difference between crankshaft direction part and thrust-anti-thrust direction part: 50 ° C

As shown in the above results, the temperature difference between the crankshaft direction portion and the thrust-anti-thrust direction portion is 15 ° C for the cylinder liner of the present invention and 25 ° C and 50 ° C for the two conventional cylinder liners. It can be seen that the cylinder liner of the present invention has a small temperature difference in the circumferential direction.

Although the present invention has been specifically described based on the embodiments, it is needless to say that the present invention is not limited to the above embodiments and various modifications can be made without departing from the scope of the invention. Absent.

An example thereof is shown in FIGS. 5 and 6. This is different from the above-mentioned embodiment only in the configuration of the uneven surface, and the other configurations are the same, so only the configuration of the uneven surface will be described. That is, this is one in which a plurality of arc-shaped concave surfaces are formed on the groove bottom surface of the annular groove 4 at the same position as in the above embodiment to form the uneven surface 21. The concave-convex surface 21 is formed by subjecting the outer peripheral surface of the cylinder liner 1 to groove machining, and then subjecting the groove bottom surface to a large number of milling operations.

Further, in the above description, the annular groove on the upper part of the liner is formed with the uneven surface which makes the flow of the cooling liquid a turbulent flow. However, of course, the cooling liquid also flows in the crankshaft direction portion below the annular groove. You may make it form the uneven surface made into a turbulent flow.

Although an example of three annular groove groups has been shown above, it is also possible to use two or four or more annular groove groups.

Further, in the above example, the cross-sectional shape of the groove is rectangular, but there is no particular limitation and it may be V-shaped, semicircular, or the like. However, a rectangle or a square is preferable to increase the heat transfer area.

Further, it goes without saying that the structure of the cooling liquid groove to which the present invention is applied is not limited to the above-mentioned groove structure, and a groove structure of another annular groove and a longitudinal groove, for example, a peripheral groove between upper and lower annular grooves. For example, a plurality of vertical grooves may be provided at intervals in the direction. Further, a spiral groove structure may be used.

In the above description, the cooling liquid groove is formed on the liner outer peripheral surface 3 and the cooling liquid passage 18 is formed between the cooling liquid groove and the bore portion inner peripheral surface 17 of the cylinder block 16. A cooling liquid groove may be formed in the inner surface of the liner and a cooling liquid passage may be formed between the cooling liquid groove and the liner outer peripheral surface. Further, cooling liquid grooves may be formed on both the outer peripheral surface of the liner and the inner peripheral surface of the bore portion of the cylinder block.

Further, in the above example, the example of the cylinders arranged in series is shown, but the present invention is not limited to this, and the present invention can also be applied to the case of cylinders arranged in a V shape or horizontally opposed cylinders. is there.

[0040]

[Effect of the device]

 As described above, according to the present invention, the flow state of the cooling liquid becomes a turbulent flow in the crankshaft direction portion, and the heat transfer area in that portion further increases, thereby increasing the cooling capacity in the crankshaft direction portion. , The temperature in the circumferential direction of the cylinder liner can be made uniform. In addition, the cylinder liner can be easily machined and assembled.

[Brief description of drawings]

1 is a transverse cross-sectional view of an annular groove portion having an uneven surface in a cylinder block fitted with the cylinder liner of FIG.

FIG. 2 is a development view showing a part of an outer peripheral surface of a cylinder liner according to the present invention.

FIG. 3 is an enlarged view showing a part of FIG.

FIG. 4 is a plan view of a cylinder block fitted with a cylinder liner according to the present invention.

FIG. 5 is a development view showing a part of an outer peripheral surface of another cylinder liner according to the present invention.

6 is a cross-sectional view of an annular groove portion having an uneven surface in the cylinder block fitted with the cylinder liner of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylinder liner 2 Collar part 3 Liner outer peripheral surface 4 Annular groove 4A 1st annular groove group 4B 2nd annular groove group 4C 3rd annular groove group 5, 6, 7, 8, 9, 10, 11, 12 Longitudinal groove 13 , 14, 15 Discharge groove 16 Cylinder block 17 Bore inner surface 18 Coolant passage 19, 20, 21 Rough surface T Thrust position AT Anti-thrust position F Front position R Rear position

Claims (1)

[Scope of utility model registration request] 1. A cooling structure for a cylinder liner for a multi-cylinder engine, wherein a groove is formed on 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, and a cooling liquid flows in the groove. A cooling structure for a cylinder liner, wherein a concavo-convex surface having a turbulent flow of cooling liquid is formed in a crankshaft direction portion.