JPH04295164A - Cooling device for internal combustion engine - Google Patents

Abstract

PURPOSE:To provide a cooling device which gradually increases cooling capacity toward the upper part of a cylinder liner in the vicinity of a combustion chamber through smooth distribution, in a cooling device for an internal combustion having a combustion chamber located in a cylinder. CONSTITUTION:Communicating passages 32 and 33 are composed of communicating grooves 12 and 13, through which a plurality of annular grooves 11 are intercommunicated axially of a cylinder liner 10, and communicating grooves 22 and 23 formed in a cylinder block 20. A spacer 34 having slits 34b the opening area of which is increased toward an upper part in the vicinity of a combustion chamber are located on a body 34a positioned facing the annular grooves 11 in a state that the body 34a is engaged internally of the communicating passages 32 and 33. The spacers 34 are engaged internally of the communicating passage 32 and 33, a refrigerant is throttled by means of the slits 34b and a flow rate of a refrigerant is increased toward an upper part.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling system for an internal combustion engine, and more particularly to a cooling system for an internal combustion engine having a combustion chamber within a cylinder.

0002

2. Description of the Related Art Conventionally, as described in Japanese Utility Model Application No. 63-168242, there has been a cooling system for cooling an internal combustion engine by providing a spiral or annular cooling groove on the outer periphery of a cylinder liner to allow a refrigerant to flow therethrough.

FIGS. 5A, 5B, and 5C show a plan view, a front view, and a side view of an example of a conventional cylinder liner, respectively. In the figure, a plurality of annular grooves 2 are formed at equal intervals on the outer periphery of a cylinder liner 1. Further, all the annular grooves 2 are communicated with each other through communication grooves 3 and 4 formed in the axial direction. The refrigerant flowing from the inflow section 5 passes through the communication groove 3 and is distributed to each annular groove 2, and is discharged from the outflow section 6 through the communication groove 4.

In a cooling device configured as shown in FIG. 5, the pressure loss is smaller than in a cooling device configured in which a single spiral cooling groove is formed from the inlet to the outlet.
The pump output for supplying the refrigerant to the annular groove 2 can be reduced.

[0005]

The heat input from the cylinder wall of an internal combustion engine is larger as the upper part of the cylinder is in direct contact with high-temperature combustion gas for a longer period of time. In the cooling device using the cylinder liner 1 shown in FIG. 5, the annular grooves 2 are formed at equal intervals, so that the cooling capacity is uniform in the axial direction of the cylinder liner 1. For this reason, there is a strong tendency for insufficient cooling in the upper part of the cylinder liner 1 near the combustion chamber, and there are concerns about piston seizure, gas leakage, etc. Furthermore, there is a strong tendency for overcooling to occur in the lower part of the cylinder liner 1, resulting in problems such as increased friction loss.

On the other hand, (2) the intervals between the annular grooves are formed closer toward the top. ■The cross-sectional area of the annular groove is made larger toward the top. Methods such as the above have been devised, but in the method (2), the cylinder wall temperature has a stepped distribution in the portion where the interval between the annular grooves is large. In method (2), the divided flow velocity decreases due to the increased cross-sectional area, and the heat transfer rate decreases, so the cooling capacity of the upper part of the cylinder cannot be improved as much as expected. Problems such as these remain, and this is not a complete solution to the above problems.

[0007]The present invention was made in view of the above-mentioned problems, and there is a gap between a plurality of cooling grooves formed in the circumferential direction of the cylinder liner and a communication groove that communicates each of the plurality of cooling grooves. By providing a throttle section with a larger degree of restriction toward the lower part of the cylinder liner, which is farther away from the combustion chamber, the flow rate of the refrigerant increases toward the upper part of the cooling groove, which is closer to the combustion chamber, resulting in a smoother distribution that increases the cooling capacity toward the upper part of the cylinder liner. The purpose is to provide engine cooling equipment.

[0008]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides cooling grooves arranged in parallel along the circumferential direction of the cylinder liner on the outer periphery of the cylinder liner fitted into the cylinder block. , a cooling device for an internal combustion engine having a communication groove communicating with each of the plurality of cooling grooves and supplying refrigerant to each of the plurality of cooling grooves, wherein the communication groove is provided between the communication groove and the plurality of cooling grooves respectively; This is a configuration in which a throttle portion is provided, the degree of which is greater in the lower part of the cylinder liner that is farther away from the combustion chamber.

[0009]

[Operation] Since the communication groove is formed by connecting each cooling groove, the pressure difference between the inlet side and the outlet side of the constriction section provided between the communication groove and the cooling groove is It is also uniform. Therefore, the flow rate of the refrigerant passing through the constriction section is proportional to the passage area of the constriction section. Therefore, the flow rate of the refrigerant decreases in the lower part of the cylinder liner where the passage area is smaller, that is, the degree of restriction is higher, and conversely, the flow rate of the refrigerant increases in the upper cooling groove, and the flow speed becomes faster, thereby increasing the cooling capacity. In this way, the constricted portion allows the cooling capacity to be adjusted even when cooling grooves are arranged at equal intervals, thereby preventing a stepped temperature distribution on the inner circumferential surface of the cylinder liner.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1A and 1B are a plan view and a sectional view of an embodiment of a cooling device for an internal combustion engine according to the present invention. Same figure (
B) represents a cross section taken along line Ib-Ib in FIG.

In the figure, on the outer periphery of the cylinder liner 10,
Similar to the conventional cylinder liner 1, a plurality of annular grooves 11 for guiding the refrigerant in the circumferential direction are arranged in parallel along the axial direction. The annular grooves 11 are arranged at equal intervals in the axial direction, and have the same cross-sectional shape.

Furthermore, communication grooves 12 and 13 communicating with all the annular grooves 11 are formed along the axial direction. The communication grooves 12 and 13 are provided at positions 180 degrees apart on the plane of the cylinder liner 10, respectively, as shown in FIG. 1(A).
Moreover, the shape of the groove is an arc.

The cylinder block 20 into which the cylinder liner 10 is fitted is formed with a bore portion 21 having an inner circumferential diameter equivalent to the outer circumferential diameter of the cylinder liner 10. Therefore, when the cylinder liner 10 is fitted into the bore portion 21, a refrigerant passage is formed by the annular groove 11 and the inner peripheral surface 21a of the bore portion 21. Furthermore, as shown in FIG. 1(A), communication grooves 22 and 23 are formed on the inner peripheral surface 21a of the communication grooves 12 and 13 so as to form a circular cross-sectional shape together with the communication grooves 12 and 13. has been done. Therefore, when the cylinder liner 10 is fitted, the communication grooves 12 and 22 form a cylindrical communication path 32, and similarly the communication grooves 13 and 23 form a cylindrical communication path 32.
Also forms a cylindrical communication passage 33.

An inlet 24 through which the refrigerant flows is formed in the lower part of the communication groove 22, and an outlet 25 is formed in the upper part of the communication groove 23. In a cooling device with such a configuration, the pressure loss is smaller than in a cooling device with a configuration in which a single spiral cooling groove is formed from the inlet to the outlet, and the refrigerant is supplied to the annular groove 11. pump output can be reduced.

In the cooling device of this embodiment, the communication path 32
, 33, spacers 34, 35 are inserted to adjust the amount of refrigerant distributed to each annular groove 11. FIG. 2 is an enlarged perspective view of a part of one spacer 34. As shown in FIG.

In the figure, the spacer 34 is a tubular main body 34.
slit 34b (slit 34b-1, 34b-2
, 34b-3, . . . are representatively represented by slits 34b). The main body 34a includes the communication path 32,
33, the outer diameter is the same as the inner diameter of the communication passages 32 and 33. The slit 34b is shown in FIG.
), when the main body 34a is fully inserted to the bottom of the communicating path 32, it is formed at the same position as each annular groove 11 (the upper end side of each slit 34b is located at the same position as each annular groove 11).
). As shown in FIG. 2, the slit 34b has a rectangular shape that is curved along the outer periphery, and the axial dimension of the slit 34b is gradually reduced toward the bottom. Therefore, the opening area of the slit 34b becomes smaller as it goes downward in the order of the slits 34b-1, 34b-2, . . . . That is, it is formed so that the degree of aperture is increased. Further, when the main body 34a is fully inserted as described above and the slit 34b is opposed to the axis of the cylinder liner 10, a shape having the same shape as the inlet 24 is formed on the main body 34a that faces the inlet 24. A hole 34c is formed.

The other spacer 35 has the same structure as the spacer 34 except that a hole 35c corresponding to the outlet 25 is provided in place of the hole 34c.

The spacers 34 and 35 having such a structure are
The slits 34b are inserted into the communication passages 32 and 33, respectively, in a direction facing the axis of the cylinder liner 10. Spacer 34
, 35 are inserted, a cylinder head (not shown) is installed, and the communication passages 32, 33 and the cylinder liner 10 are installed.
is closed at the top.

When the spacers 34 and 35 have been completely inserted, each slit 34b is located within the annular groove 11 and communicates the inside of the spacers 34 and 35 with the annular groove 11, as shown in FIG. 1(B). , and the holes 34c and 35c are the inlet 24.
The outlet 25 and the inside of the spacers 34 and 35 are communicated with each other. Therefore, the refrigerant enters the spacer 34 from the inlet 24 through the hole 34c and is distributed to each annular groove 11 through each slit 34b. The refrigerant that flows in the annular groove 11 along the circumferential direction of the cylinder liner 10 and absorbs heat enters the spacer 35 through each of the slits 34b of the other spacer 35, and is discharged from the outlet 25 through the hole 35c. be done.

During such circulation of the refrigerant, the interiors of the spacers 34 and 35 have a uniform pressure distribution because they have no internal partitions. Further, the pressure within the plurality of annular grooves 11 is also the same within any of the annular grooves 11 between the spacers 34 and 35 having a uniform pressure distribution. Therefore, when focusing on the slits 34b of the spacer 34, the pressure difference between the inlet side and the outlet side of each slit 34b arranged in parallel in the axial direction is equal in all slits 34b. Note that the pressure on the inlet and outlet sides of each slit 34b actually increases as it goes downward due to the action of gravity, but the pressure due to gravity is equally applied to the inlet and outlet sides. Therefore, when taking the pressure difference between the inlet side and the outlet side, the pressure due to gravity can be ignored, and the pressure difference is equal in all the slits 34b. Therefore, the flow rate of the refrigerant passing through the slit 34b is simply proportional to the passage area of the slit 34b. Therefore, as described above, in this embodiment, in which the slit 34b is provided at the entrance of each annular groove 11, the opening area of which is smaller toward the lower part, as shown by the length of the arrow A in FIG. , the flow rate of the refrigerant increases, the flow speed becomes faster, and the cooling capacity increases.

Furthermore, in this embodiment, the outflow side spacer 35 is also formed with a slit 34b having a variation in the degree of aperture similar to that of the spacer 34. Therefore, the change in the refrigerant flow velocity in each annular groove 11 becomes more remarkable than when only the spacer 34 is installed.

As described above, in this embodiment, by providing the slits 34b with different degrees of aperture at the respective entrances of the annular grooves 11, a cooling device is constructed in which the cooling capacity is gradually weakened from the upper part to the lower part of the cylinder liner 10. do. Moreover, since the annular grooves 11 are provided at equal intervals, the distribution of cooling capacity is not stepped but is smooth from the top to the bottom. Therefore, when the internal combustion engine is operating, it is possible to equalize the temperature of the inner circumferential surface of the cylinder liner 10 in the axial direction.

Furthermore, since the spacers 34 and 35 are insertable, the cylinder liner 10 and the cylinder block 20
The shape of the cooling device is simple and the manufacturing cost of the cooling device is not much different from that of the conventional cooling device.

Furthermore, since the cooling capacity of each annular groove can be adjusted simply by changing the specifications of the slit, the adjustment work for optimizing the cylinder liner wall temperature when developing a new internal combustion engine is much easier than before. becomes. Further, for internal combustion engines of the type with the same bore diameter, the cylinder liner 10 body can be shared by simply preparing spacers with slit specifications corresponding to the respective outputs, which can also be expected to reduce costs.

It should be noted that the present invention is not limited to the above-mentioned embodiment, and the same effect as described above can be obtained by fitting one of the spacers 34 and 35 into the communication passages 32 and 33. Further, a modification shown in FIG. 3 is also possible.

FIGS. 3A and 3B are a plan view and a sectional view of a modification of the cooling device for an internal combustion engine according to the present invention. Same figure (
B) represents a cross section taken along the line IIIb-IIIb in FIG.

The modified cooling device shown in FIG. 3 has the same structure as the above embodiment except for the spacer. Therefore, Figure 1
The same reference numerals are given to the parts corresponding to the constituent parts shown in , and the explanation thereof will be omitted.

In FIG. 3, cylindrical communication passages 32 and 33 are formed between the cylinder liner 10 and the cylinder block 20, as in the above embodiment. A spacer 40 is fitted in the communication path 32 on the inflow side. FIG. 4 is an enlarged perspective view of a part of the spacer 40. As shown in FIG.

In the figure, the spacer 40 is a tubular main body 40.
Hole 40b (hole 40b-1, 40b-2, 40b-3
... (represented by holes 40b) are bored. As shown in FIG. 4, the holes 40b have a rectangular shape that is curved along the outer periphery, and all the holes 40b have the same shape. Further, the axial dimension of the hole 40b is the same as the axial width dimension of the annular groove 11. and,
Each hole 40b is formed at the same position as each annular groove 11 when the main body 40a is fully inserted to the bottom of the communication path 32, as shown in FIG. 3(B). This hole 40b has filters 41 (filters 41-1, 41-2, 41
-3... (represented by a filter 41) are respectively attached to cover the holes 40b. And this filter 4
1 is thinner at the top and thicker at the bottom.

A hole 40c having the same shape as the inlet 24 is formed on the main body 40a facing the inlet 24 when the main body 40a is fitted.

When the spacer 40 configured as described above is fitted into the communication path 32, the refrigerant enters the spacer 40 from the inlet 24 through the hole 40c, passes through each filter 41 and the hole 40b, and enters each annular shape. distributed in the groove 11. The refrigerant that has cooled the cylinder liner 10 gathers in the communication passage 33 and is discharged from the outlet 25.

At this time, each filter 41 has a spacer 40
This serves as a resistance to the refrigerant flowing into the annular groove 11 from inside, and acts as a constriction portion that throttles the refrigerant flowing into the annular groove 11, similar to the slit 34b in the above embodiment. Changing the thickness of the filter 41 has the same effect as changing the resistance value, that is, the degree of aperture. Therefore, during refrigerant circulation, the thinner the upper part of the filter 41, the greater the flow rate of the refrigerant flowing into the annular groove 11 from within the spacer 40, and conversely, the thicker lower part of the filter 41 experiences greater resistance, reducing the flow rate of the refrigerant. descend.

As described above, even in this modification example in which the holes 40b have the same size and the filter 41 is installed therein, the filter 41 becomes thicker toward the bottom, the flow rate of the refrigerant is adjusted, and the cooling capacity increases toward the annular groove 11 at the top. It is possible to obtain the same enhanced effect as in the above embodiment.

The filter 41 also prevents dirt, rust, etc. from entering the annular groove 11. Therefore, the maintenance work that conventionally required removing the cylinder liner 10 from the cylinder block 20 and removing dust, rust, etc. in the refrigerant passage can be reduced to the simple work of replacing the spacer 40 in this modification. . In this way, according to this modification, in addition to the effects of the above-described embodiments, there is also an effect of simplifying maintenance of the internal combustion engine and reducing operating costs.

[0035]

Effects of the Invention As described above, according to the present invention, by providing a constriction portion between the communication groove and the cooling groove, the degree of constriction of which is increased toward the lower part of the cylinder liner, the cylinder liner can be smoothly distributed. It is possible to configure a cooling device in which the cooling capacity is increased toward the upper part, and the temperature of the inner circumferential surface of the cylinder liner can be made uniform in the axial direction during operation of the internal combustion engine. Moreover, the manufacturing cost of the cooling device does not increase much compared to the conventional method.

In addition, since the cooling capacity of each cooling groove can be adjusted only by changing the degree of restriction, the adjustment work for optimizing the cylinder liner wall temperature can be made easier, and the internal combustion For the engine, the cylinder liner body can be shared by simply providing throttle sections corresponding to the respective outputs, which can also be expected to reduce costs.

[Brief explanation of the drawing]

FIG. 1 is a structural diagram of an embodiment of a cooling device for an internal combustion engine according to the present invention.

FIG. 2 is an enlarged perspective view of a part of the spacer in FIG. 1;

FIG. 3 is a structural diagram of a modification of the cooling device for an internal combustion engine according to the present invention.

FIG. 4 is an enlarged perspective view of a part of the spacer in FIG. 3;

FIG. 5 is a structural diagram of an example of a cylinder liner of a conventional device.

[Description of symbols] 10 Cylinder liner 11 Annular groove 12, 13, 22, 23 Communication groove 20 Cylinder block 24 Inlet 25 Outlet 32, 33 Communication passage 34, 35, 40 Spacer 34a, 40a Main body 34b Slit 34c, 35c, 40b, 40c hole 41 filter

Claims (1)

[Claims] Claims: 1. A plurality of cooling grooves arranged in parallel along the circumferential direction of the cylinder liner on the outer periphery of a cylinder liner fitted in a cylinder block; In the cooling device for an internal combustion engine, the degree of aperture is increased in the lower part of the cylinder liner further away from the combustion chamber between the communication groove and the plurality of cooling grooves. A cooling device for an internal combustion engine, characterized by being provided with a throttle section.