JPH0329560Y2 - - Google Patents

Description

[Detailed explanation of the idea] [Industrial application field] The present invention relates to a cylinder liner.

[Conventional technology]

Conventionally, cooling water has been used to cool the engine, and in the case of a dry liner, a cooling water passage is provided in the cylinder block, and in the case of a wet liner, a recess provided on the inner circumferential surface of the cylinder block bore and the outer circumference of the liner. Cooling water flows through the passage formed by the liner and circulates from the bottom of the liner to the top and even to the cylinder head to cool the engine.

[Problem that the invention attempts to solve]

The heat generated in the combustion chamber is dissipated through each part of the cylinder head, cylinder liner, piston, and piston ring, but when it comes to the wall surface of the cylinder liner, the temperature of the upper part of the liner near the combustion chamber is highest, followed by the center part. , lower in the bottom order. In recent years, improving engine performance has become an essential requirement, and the amount of heat generated in the combustion chamber has also increased, resulting in a considerably high temperature in the upper part of the liner near the combustion chamber.

Therefore, when designing a compact, high-speed, high-load engine, the problem has arisen that the conventional cylinder cooling structure is unable to sufficiently cool the upper part of the liner, especially in the vicinity of the combustion chamber.

The present invention was developed in view of the above points, and allows for cooling that corresponds to the temperature gradient in the axial direction of the cylinder liner (high at the top, low at the bottom), and effectively removes the increasing amount of heat generated in the combustion chamber. The purpose is to keep the temperature of the cylinder wall uniformly low.

[Means for solving problems]

The structure of the present invention is that a plurality of annular grooves and an axial groove that communicates them are formed on the outer circumferential surface of the liner, and this liner is fitted into the bore of the cylinder block, and the liner is inserted into the inner circumferential surface of the bore of the cylinder block. In a cylinder liner in which a space defined by the grooves and the grooves forms a coolant flow path, the plurality of annular grooves are divided into a plurality of annular groove groups, and the annular groove groups in which the plurality of annular grooves are assembled are divided into a plurality of annular groove groups. Two axial grooves are formed that allow the annular grooves to communicate with each other and serve as the outlet and inlet of the coolant, and the outlet and inlet of the coolant in adjacent annular groove groups communicate in series, and each annular groove group The total cross-sectional area of the coolant flow path in the liner is characterized by decreasing from the bottom to the top in the axial direction of the liner.

Each of the plurality of annular groove groups may be a collection of a plurality of annular grooves, or the first annular groove group counted from the upper end of the liner may consist of one annular groove, The remaining annular groove group may be a collection of a plurality of annular grooves.

The number of annular groove groups is 2, 3, or 4 or more.

[Effect]

The coolant flows circumferentially around the liner through the annular grooves in the annular groove group, moves from the outlet of the annular groove group to the inlet of the adjacent annular groove group, and flows through the annular groove of the next annular groove group to the liner. The coolant flows circumferentially around the outer periphery, and in the same manner as described above, the coolant moves to successively adjacent annular groove groups and flows around the liner outer periphery through the annular groove groups. At this time, since the total cross-sectional area of the coolant flow path in each annular groove group decreases from the bottom to the top of the liner, the flow velocity is higher in the annular groove group in the upper part of the liner. Therefore, the heat transfer coefficient of the coolant is larger in the upper part of the liner, and the cooling capacity is higher in the upper part of the liner. In this way,
Appropriate cooling is performed in response to the temperature gradient in the liner axial direction (higher at the top and lower at the bottom).

〔Example〕

In an in-line 4-cylinder 96 horsepower diesel engine, a groove for a coolant passage was formed on the outer peripheral surface of the cylinder liner with an inner diameter of 84 mmφ and a stroke of 89 mm.

That is, as shown in FIGS. 1 and 2, the cylinder liner 1 has a flange 2 at the upper end, and 18 pieces are arranged at intervals in the axial direction over the entire liner outer peripheral surface 3 below the flange 2. An annular groove 4 is formed. These annular grooves 4 are divided into three annular groove groups.

These three annular groove groups are the first annular groove 4 from the first annular groove 4 to the fourth annular groove 4 on the upper end side of the liner.
An annular groove group 4A, a second annular groove group 4B from the fifth annular groove 4 to the tenth annular groove 4, and a third annular groove group from the 11th annular groove 4 to the last 18th annular groove 4. It consists of an annular groove group 4C.

The first annular groove group 4A has a groove in the liner circumferential direction.
Two axial grooves 5 and 6 are located at two positions 180 degrees apart and connect the annular grooves 4 to each other. ) is formed, and one axial groove 5
serves as a coolant inlet, and the other axial groove 6 serves as a coolant outlet. Similarly, in the second annular groove group 4B, two axial grooves 7 are provided at the same two positions in the circumferential direction as the axial grooves 5 and 6 of the first annular groove group 4A, which connect the annular grooves 4 to each other. , 8 (these consist of concave notches formed in the liner outer circumferential surface 3 between a plurality of adjacent annular grooves 4), and
The axial groove 7 located on the coolant outlet side of A serves as the coolant inlet, and the other axial groove 8 serves as the coolant outlet. Similarly, in the third annular groove group 4C, two axial grooves that connect the annular grooves 4 to each other are provided at the same two positions in the circumferential direction as the axial grooves 7 and 8 of the second annular groove group 4B. Grooves 9 and 10 (these consist of concave notches formed in the liner outer circumferential surface 3 between a plurality of adjacent annular grooves 4) are formed, and the shaft is located on the coolant outlet side of the second annular groove group 4B. The directional groove 9 serves as an inlet for the coolant, and the other axial groove 10 serves as the outlet for the coolant.

The axial grooves 6 that form the outlet of the coolant in the first annular groove group 4A and the axial grooves 7 that form the inlet of the coolant in the second annular groove group 4B are the axial grooves 6,
An axial groove 11 consisting of one concave notch formed in the liner outer peripheral surface 3 between the fourth annular groove 4 and the fifth annular groove 4 at the same position in the circumferential direction as 7. are connected in series. Similarly, the axial groove 8 forming the outlet of the cooling liquid of the second annular groove group 4B
The axial groove 9 forming the inlet of the cooling liquid of the third annular groove group 4C is at the same position in the circumferential direction as these axial grooves 8 and 9, and the 10th annular groove 4 and the 11th annular groove
They communicate in series with the th annular groove 4 through an axial groove 12 consisting of a single concave notch formed in the liner outer circumferential surface 3.

The annular groove 4 has a rectangular cross section, and all have the same cross-sectional area.

This cylinder liner 1 is the cylinder block 13.
(See FIG. 3), and the space defined by the inner circumferential surface 14 of the bore and the grooves 4 to 12 of the liner 1 forms a coolant flow path 15.

Therefore, as shown in FIG. 1, the coolant that has flowed into the axial groove 5 forming the entrance of the first annular groove group 4A of the cylinder liner 1 through the not-illustrated passage of the cylinder block 13 flows into the first annular groove group 4A. Annular groove group 4A
As shown in FIG. 2, the annular groove 4 flows 180 degrees to the opposite side, and as shown in FIG. It flows into the directional groove 7. Then, the second annular groove group 4
Flowing 180 degrees to the opposite side through the annular groove 4 of B,
As shown in FIG. 1, the water flows from the axial groove 8, which is the outlet of the second annular groove group 4B, into the axial groove 9, which is the inlet of the third annular groove group 4C. Then, it flows 180 degrees to the opposite side through the annular groove 4 of the third annular groove group 4C,
The water flows out from the axial groove 10 forming the outlet of the third annular groove group 4C shown in FIG. 2 into a passage (not shown) of the cylinder block 13.

In this case, the total cross-sectional area of the coolant flow paths in the three annular groove groups 4A, 4B, and 4C has a ratio of 2:3:4, and the flow rate of the coolant flowing through each annular groove group 4A, 4B, and 4C is as follows: The second annular groove group 4B in the center is larger than the third annular groove group 4C in the lower part, and the first annular groove group 4 in the upper part is larger than the second annular groove group 4B in the center.
A is larger.

Therefore, the heat transfer coefficient of the cooling liquid increases toward the upper part of the liner, and the cooling capacity increases, so that appropriate cooling corresponding to the temperature gradient in the axial direction of the liner is performed. Note that the flow rate of the coolant was able to be lower than that of the conventional system.

In the above embodiment, the cross-sectional shape of the annular groove 4 is rectangular, but it is not limited to this, and may be V-shaped, semicircular, etc., without any particular limitation.
However, in order to increase the heat transfer area, a rectangular shape as in this embodiment is desirable.

In addition, in the above embodiment, a plurality of annular grooves formed at intervals in the axial direction of the liner are divided into three annular groove groups, and the total cross-sectional area of the coolant flow path in each annular groove group is increased from the bottom to the top. However, it is divided into two annular groove groups or four or more annular groove groups, and the total cross-sectional area of the coolant flow path in each annular groove group is made smaller from the bottom to the top. You can.

In addition, in the above embodiment, each annular groove group is a collection of a plurality of annular grooves, but in addition, the first annular groove group counting from the upper end of the liner is one annular groove, and the remaining annular grooves are The annular groove group can also be a collection of a plurality of annular grooves.

In the above embodiment, engine system lubricating oil was used as the coolant. Although cooling water may be used as the coolant, using engine lubricating oil not only prevents corrosion of parts that occurs during water cooling, but also eliminates pitting corrosion and electrolytic corrosion caused by cavitation. Furthermore, even if the coolant leaks from the fitting portion between the cylinder liner and the cylinder block, no problem will occur if it is lubricating oil. Note that it is possible to use a cooling structure for cooling the cylinder head portion in a separate system from that for cooling the cylinder block portion. In this case, the only seal between the cylinder head and cylinder block is a gas seal for combustion gas and compressed air.
The shape of the cylinder head gasket is simplified,
It is easy to assemble and can be used at low cost.

The engine cooling structure described above can be applied to both diesel engines and gasoline engines.

Furthermore, this cooling structure makes it possible to use an aluminum die-cast cylinder block or an assembled cylinder block.

[Effects of the Invention] As explained above, the present invention provides the following effects.

(a) The coolant flows sequentially through each annular groove group,
At this time, since the total cross-sectional area of the coolant flow path in each annular groove group decreases from the bottom to the top of the liner, the flow velocity is higher in the annular groove group in the upper part of the liner. Therefore, the heat transfer coefficient of the coolant is larger in the upper part of the liner, and the cooling capacity is higher in the upper part of the liner. In this way, appropriate cooling is achieved in response to the temperature gradient in the axial direction of the liner (high at the top, low at the bottom), and the upper part of the liner near the combustion chamber, where heat generation is greatest, is also sufficiently cooled and the cylinder wall temperature can be kept uniformly low.

(b) Since the coolant flows through the annular groove group, the flow rate of the coolant becomes high, the heat transfer coefficient is high, the increase in pressure loss can be suppressed as much as possible, and the heat transfer area can be made large.

(c) Since the coolant flows guided by a plurality of annular grooves formed on the outer circumferential surface of the liner, the flow of the coolant is uniform without unevenness, and uniform cooling can be achieved over the entire circumference of the liner.

(d) Since the total cross-sectional area of the coolant flow path in each annular groove group can be made smaller from the bottom to the top of the liner, the groove width and depth of the annular groove itself in each annular groove group can be Great degree of freedom.
Therefore, the width and depth of the annular groove itself can be optimally selected by taking into consideration the flow path resistance, the strength of the thin liner portion in the annular groove portion, and the like. For example, in terms of thinning the cylinder liner, by reducing the width of the annular groove and increasing the number of annular grooves, the width of the thin part of the liner where the annular groove is formed and the strength is weakened can be reduced. Therefore, even if the thickness of the cylinder liner is made thinner, it can be made durable in terms of strength. Therefore, it is possible to reduce the weight and size of the engine, and it is also possible to obtain a larger displacement with an engine of the same size.

(e) Since it is only necessary to form a plurality of annular grooves and an axial groove that communicates them at a predetermined position, machining is easy, and the work of inserting the liner into the cylinder block is not difficult.
Easy to process and assemble.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIGS. 1 and 2 are perspective views of a cylinder liner, respectively, and they are different from each other.
FIG. 3, viewed from the opposite side 180 degrees, is a vertical sectional view showing a part of the bore of the cylinder block fitted with the cylinder liner, taken along the axial groove of the liner. 1 is a cylinder liner, 2 is a flange, 3 is an outer peripheral surface of the liner, 4 is an annular groove, 4A is a first annular groove group, 4B is a second annular groove group, 4C is a third annular groove group, 5, 6,
7, 8, 9, 10, 11, 12 are axial grooves, 13
is the cylinder block, 14 is the inner peripheral surface of the bore, 15
is the coolant flow path.

Claims (1)

[Claims for Utility Model Registration] (1) A plurality of annular grooves and an axial groove that communicates them are formed on the outer circumferential surface of the liner, and this liner is fitted into the bore of the cylinder block,
In a cylinder liner in which a space defined by the inner peripheral surface of the bore portion of the cylinder block and the groove forms a coolant flow path, the plurality of annular grooves are divided into a plurality of annular groove groups. Two axial grooves are formed in the group of annular grooves, which communicate the annular grooves with each other and form the outlet and inlet of the coolant, and the outlet and inlet of the coolant are in series in the adjacent annular groove groups. A cylinder liner characterized in that the total cross-sectional area of a coolant flow path in each annular groove group becomes smaller from the bottom to the top in the axial direction of the liner. (2) The cylinder liner according to claim 1, wherein each of the plurality of annular groove groups is a collection of a plurality of annular grooves. (3) Regarding the plurality of annular groove groups, the first annular groove group counting from the upper end of the liner consists of one annular groove, and the remaining annular groove groups are a collection of a plurality of annular grooves. A cylinder liner according to claim 1 of the utility model registration claim, characterized in that: (4) The cylinder liner according to claim 1, 2, or 3 of the utility model registration, characterized in that the number of annular groove groups is 2, 3, or 4 or more.