JPH04342859A - Cooling structure of cylinder liner - Google Patents

Abstract

PURPOSE:To uniformalize temperature in the circumferential direction of a cylinder liner, to be hard to lower the circularity of the inner peripheral surface of the liner, and to facilitate production. CONSTITUTION:A cylinder liner 1 where plural annular grooves 4 and longitudinal grooves connected thereto are formed on the outer peripheral surface is fitted in each bore portion of a cylinder block 16 of a multi-cylinder engine. A flow control member 19 for a cooling liquid is installed in the annular groove 4 of the liner upper portion. The member comprises an eddy flow forming member 19a and a laminar flow forming member 19b, wherein the eddy flow forming member 19a is disposed to be in a region in the crankshaft direction. Thus, a cooling liquid flowing through the annular groove 4 is formed into a laminar flow in the thrustantithrust direction regions, but it is formed into an eddy flow in a region in the crankshaft direction, so that the coefficient of heat transfer in the region in the crankshaft direction becomes larger than that in the region in the thrust-antithrust direction so as to increase the cooling capability in the region in the crankshaft direction.

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 in a multi-cylinder engine.

0002

BACKGROUND OF THE INVENTION Recently, a cooling structure for a cylinder liner in which a cooling liquid flows through a groove provided in one or both of the outer circumferential surface of the cylinder liner and the inner circumferential surface of a bore portion of a cylinder block has been attracting attention. This is because it is easier to control cooling depending on the location of the cylinder liner compared to the jacket type cooling structure that has been used for a long time.

[0003] In order to realize cooling according to each part of the cylinder liner in the axial direction, for example,
No. 242 proposes a cylinder liner in which a plurality of annular groove groups are formed on the outer peripheral surface.

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 155°C in the thrust-anti-thrust direction, and about 180°C in the crankshaft direction. It became clear that it could not be cooled sufficiently. This temperature difference in the circumferential direction is significantly large in the upper part of the cylinder liner.

[0005] In order to solve the above problem, firstly,
-78517, the outer peripheral surface of the cylinder liner is cylindrical, and the groove bottom of the circumferential groove has a long axis in the direction of the crankshaft, and a thrust-
A cylinder liner has been proposed that is oval in shape with its minor axis in the anti-thrust direction. The flow velocity of the coolant flowing in the circumferential groove of the cylinder liner increases at a portion in the crankshaft direction, and this portion is characterized by a large cooling capacity.

[0006]

[Problems to be Solved by the Invention] However, since the wall thickness of this type of cylinder liner is not uniform in the circumferential direction, the roundness of the inner circumferential surface of the cylinder liner tends to decrease, and it is difficult to process grooves in the circumferential direction. There were two problems: cam turning was required and productivity was low.

The present invention has been made in view of the above points, and
It is an object of the present invention to provide a cooling structure for a cylinder liner that can make the temperature uniform in the circumferential direction of the liner, prevent the roundness of the inner circumferential surface of the liner from decreasing, and facilitate production.

[0008]

[Means for Solving the Problems] According to the configuration of the present invention, a cylinder liner is attached to each cylinder bore of a cylinder block of a multi-cylinder engine, and one or both of the outer circumferential surface of the cylinder liner and the inner circumferential surface of the bore portion of the cylinder block. In a cylinder liner cooling structure in which a coolant groove is formed in the cylinder liner and the coolant flows through the groove, a turbulence forming member is disposed in the groove to make the flow state of the coolant in a portion in the direction of the crankshaft turbulent. It is characterized by what it did.

[0009] Preferably, the turbulent flow forming member is provided with a laminar flow forming member that makes the flow state of the coolant laminar.

0010

[Operation] The coolant flows at high speed in the groove, and the flow is laminar in the thrust-anti-thrust direction, but in the crankshaft direction, the flow state of the coolant becomes turbulent due to the presence of the turbulence forming member. Become. Therefore, the heat transfer coefficient between the coolant and the cylinder liner becomes larger in the crankshaft direction, and the temperature in the circumferential direction of the cylinder liner can be made uniform.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In an inline 4-cylinder oil-cooled diesel engine,
Coolant grooves were formed on the outer peripheral surface of the cylinder liner. That is,
In FIG. 2, the cylinder liner 1 has a flange 2 at its upper end, and 18 annular grooves 4 are formed at intervals in the axial direction on the outer circumferential surface 3 of the liner below the flange 2. These annular grooves 4 are divided into three annular groove groups.

These 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 side of the liner, and an annular groove group 4A from the fourth annular groove 4 to the ninth annular groove 4. It consists of a second annular groove group 4B up to the annular groove 4, and a third annular groove group 4C from the 10th annular groove 4 to the last 18th annular groove 4.

[0013] In the first annular groove group 4A, two longitudinal grooves 5 and 6 are formed at two positions 180 degrees apart in the circumferential direction of the liner to communicate the annular grooves 4 with each other. Groove 5 forms the inlet for the cooling liquid, and the other longitudinal groove 6 forms the outlet for the cooling liquid.

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

Similarly, the third annular groove group 4C also has two grooves that connect the annular grooves 4 to each other at the same two positions in the circumferential direction as the vertical 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 coolant outlet side of the second annular groove group 4B serves as the coolant inlet, and the other longitudinal groove 10 serves as the coolant outlet. Eggplant.

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

Similarly, the vertical groove 8 forming the outlet of the cooling liquid in the second annular groove group 4B and the vertical groove 9 forming the inlet of the cooling liquid in the third annular groove group 4C are Directional grooves 8, 9
and a longitudinal groove 12 provided at the same position in the circumferential direction.
are connected in series.

A discharge groove is formed in the lower part of the outer peripheral surface 3 of the liner. That is, on the outer circumferential surface 3 of the liner 1, there is a longitudinal groove 13 connected to the lower end of the longitudinal groove 10 forming the outlet of the third annular groove group 4C and arranged on an extension line thereof, and an annular groove 14 connected to the lower end of the longitudinal groove 13. and a longitudinal groove 15 connected to this at its upper end 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.

Note that these discharge grooves 13, 14, and 15 are formed in order to use cooling oil as a cooling fluid and discharge it to the oil pan. For example, when cooling water is used as a cooling fluid, In this case, the cooling water is configured to flow out into a discharge passage provided in the cylinder block. Of course, the cooling oil may also be configured to flow out into the exhaust passage of the cylinder block.

[0020] In-line 4 incorporating the above cylinder liner 1
The cylinder oil-cooled diesel engine has a displacement of 3 liters.
Cylinder liner inner diameter: 98mm
Outer diameter: 108mm
Annular groove width: 2mm
Depth: 2.5mm
Cooling oil temperature (inlet): 100℃
Flow rate: 30l/min
Operating conditions: 3500r
pm, 4/4 load.

This cylinder liner 1 is fitted into each bore of a cylinder block 16 (see FIG. 3), and the space defined by the inner circumferential surface 17 of the bore of the cylinder block 16 and the grooves 4 to 15 is filled with cooling fluid. Coolant flow control members are installed in the three annular grooves 4 of the first annular groove group 4A forming a passage 18 (see FIGS. 1 and 4).

Coolant flow control member 19 (FIG. 1)
and Fig. 4) consists of a turbulent flow forming member 19a made by twisting a thin strip plate spirally and bending it into an arc shape, and a laminar flow forming member 19b continuing from the turbulent flow forming member 19a by simply bending a thin strip plate into an arc shape. Turbulent flow forming member 1 is a thin plate member in the shape of a broken ring.
A pair of 9a are provided at radially opposite portions of the member 19. And this coolant flow control member 19
is installed in the annular groove 4 so that the turbulence forming member 19a is located in the crankshaft direction.

The rotation of the flow control member 19 may be prevented by appropriately using a means for preventing rotation of a piston ring on a piston of a two-stroke engine having an intake/exhaust port. For example, by driving a pin 21 into a radial pin hole 20 provided in the annular groove 4 of the cylinder liner 1 (see FIG. 4), or by driving a pin axially into one of the upper and lower surfaces of the annular groove 4, The protruding portion of the pin in the annular groove 4 engages with the turbulence forming member 19a of the flow control member 19 to prevent rotation.

Coolant flow control member 1
It is preferable that the abutment position 9 is aligned with the longitudinal groove position.

The flow of the cooling oil will be explained below. It passes through the cooling oil supply path provided in the cylinder block 16,
The cooling oil that has flowed into the longitudinal groove 5 forming the entrance of the first annular groove group 4A of the cylinder liner 1 flows through the annular groove 4 of the first annular groove group 4A 180 degrees to the opposite side, and groove group 4
It flows from the longitudinal groove 6 which forms the outlet of A into the longitudinal groove 7 which forms the entrance of the second annular groove group 4B.

Then, the annular groove 4 of the second annular groove group 4B is
It flows 80 degrees to the opposite side, and flows from the vertical groove 8 forming the outlet of the second annular groove group 4B to the vertical groove 9 forming the entrance of the third annular groove group 4C.

Then, the annular groove 4 of the third annular groove group 4C is
A vertical groove 13 that flows 80 degrees to the opposite side and continues from the vertical groove 10 that forms the exit of the third annular groove group 4C.
The oil flows into the annular groove 14, flows circumferentially through the annular groove 14, falls from the two longitudinal grooves 15 at the bottom onto the main shaft of the crankshaft (not shown), and then flows into the oil pan (not shown). .

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

The flow state of the cooling oil is a laminar flow in the thrust-anti-thrust direction, but in the present invention,
In the first annular groove group 4A, since the turbulent flow forming member 19a is arranged in the crankshaft direction portion of the annular groove 4, the flow state of the cooling oil in the crankshaft direction portion becomes turbulent. Therefore, the heat transfer coefficient between the cooling oil and the cylinder liner 1 is larger in the crankshaft direction than in the thrust-anti-thrust direction, so that the temperature of the liner 1 in the circumferential direction can be made uniform. Since the flow control member 19 is made of a thin plate, an increase in pressure loss due to the presence of the flow control member 19 of the coolant flowing in the coolant passage can be minimized.

According to the calculation results of heat conduction analysis performed on the above-mentioned in-line four-cylinder oil-cooled diesel engine, the temperature of the liner wall of the cylinder liner 1 facing the combustion chamber is as follows, and the temperature in the circumferential direction of the cylinder liner 1 is as follows. It was shown that the temperature at Crankshaft direction part
160℃ thrust-anti-thrust direction part 1
For comparison at 50°C, coolant flow control member 19
The conventional case in which no was used was as follows. Crankshaft direction part
180℃ thrust-anti-thrust direction part 1
55℃

Note that the shape of the coolant flow control member is not limited to the shape shown above. For example, it may be made of a thin plate in which a part whose distance from the wall surface of the coolant passage is constant and a part whose distance from the wall surface of the coolant passage increases or decreases are connected.

Furthermore, in the above description, the coolant flow control member is attached to the annular groove at the upper part of the liner, but it goes without saying that the coolant flow control member may also be attached to the annular groove below this.

Furthermore, 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, the structure of the coolant groove to which the present invention is applied is not limited to the above-mentioned annular groove group structure, but may be other annular groove group structures, spiral grooves, or the like. If a plurality of vertical grooves are provided at intervals in the circumferential direction between the upper and lower annular grooves, a cooling fluid flow control member is provided in the annular groove as described above. In addition, it is preferable to arrange a turbulence forming member in a longitudinal groove in a portion in the direction of the crankshaft.

[0034] In the above, a coolant flow control member consisting of a turbulent flow forming member and a laminar flow forming member is arranged in the annular groove, but the turbulent flow forming member makes the flow state in the annular groove turbulent. Alternatively, only the annular groove may be disposed in the crankshaft direction portion of the annular groove.

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, in order to increase the heat transfer area, a rectangular or square shape is better.

In the above, the coolant groove is formed on the liner outer circumferential surface 3, and the coolant groove is formed on the inner circumferential surface 1 of the bore portion of the cylinder block 16.
Although a coolant passage 18 is formed between the cylinder block 16 and the liner outer circumferential surface 3, a coolant groove is formed in the bore inner circumferential surface 17 of the cylinder block 16, and a coolant passage is formed between this and the liner outer circumferential surface 3. Good too. Furthermore, coolant grooves may be formed on both the liner outer circumferential surface 3 and the bore inner circumferential surface 17 of the cylinder block 16.

[0037]

As explained above, according to the present invention, in a multi-cylinder engine, the flow state of the coolant is controlled according to the circumferential position of the cylinder liner, and the temperature in the circumferential direction of the cylinder liner is uniformly maintained. can. Furthermore, since the thickness of the cylinder liner can be made uniform, the roundness of the inner periphery is less likely to deteriorate, resulting in excellent productivity.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a portion of a cylinder block fitted with a cylinder liner and equipped with a coolant flow control member.

FIG. 2 is a developed view showing a part of the outer circumferential surface of the cylinder liner.

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

FIG. 4 is a longitudinal cross-sectional view of a detent pin portion of a coolant flow control member in a cylinder block fitted with a cylinder liner.

[Explanation 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 1
3, 14, 15 Discharge groove 16 Cylinder block 17 Bore inner peripheral surface 18 Coolant passage 19 Coolant flow control member 19a Turbulent flow forming member 19b Laminar flow forming member 20 Pin hole 21 Stopping pin T Thrust position AT Anti-thrust position F Front position R Rear position

Claims (2)

[Claims] Claim 1: A cylinder liner is installed in each cylinder bore of a cylinder block of a multi-cylinder engine, and a coolant groove is formed in one or both of the outer circumferential surface of the cylinder liner and the inner circumferential surface of the bore portion of the cylinder block. A cooling structure for a cylinder liner in which a coolant flows through the cylinder liner, characterized in that a turbulent flow forming member is disposed in the groove to create a turbulent flow of the coolant in a portion in the direction of the crankshaft. structure. 2. A cylinder liner is installed in each cylinder bore of a cylinder block of a multi-cylinder engine, and a coolant groove is formed on one or both of the outer circumferential surface of the cylinder liner and the inner circumferential surface of the bore portion of the cylinder block. In the cooling structure of the cylinder liner in which the coolant flows through the cylinder liner, there is a turbulent flow forming member in the groove that makes the flow state of the coolant in the crankshaft direction part a turbulent flow, and a turbulent flow forming member that makes the flow state of the coolant in the crankshaft direction part a laminar flow. A cooling structure for a cylinder liner, characterized in that a laminar flow forming member is provided.