JPH04358745A - Cooling device for internal combustion engine - Google Patents

Abstract

PURPOSE:To reduce line resistance due to the curvature of a refrigerant inflow port in a cooling device cooling an internal combustion engine by providing annular grooves on the cylinder liner outer periphery to flow a refrigerant. CONSTITUTION:A circular arc part 19 is provided on a link-connection part on a side where at least a refrigerant flows out of the communication-connection part of a refrigerant inflow port 17 and a longitudinal groove 14, to increase the flow rate of the nearest refrigerant in respective annular grooves on the lower side of any annual groove nearest to a combustion chamber.

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 that cools an internal combustion engine by providing an annular groove on the outer periphery of a cylinder liner to allow a refrigerant to flow therethrough.

0002

2. Description of the Related Art A cylinder block in which several cylinders are arranged and a cylinder head located on the upper surface of the cylinder block and having a recess on the lower surface form a combustion chamber of an internal combustion engine. Further, the outer circumferential surface of the cylinder liner is fitted onto the inner circumferential surface of the bore portion of the cylinder block. Therefore, high-temperature heat generated in the combustion chamber due to engine operation is transferred to the cylinder liner and the like through the cylinder block and cylinder head.

Therefore, in order to cool the wall surface of the cylinder liner and prevent the refrigerant from boiling, a refrigerant passage is formed between the inner peripheral surface of the cylinder block bore and the outer peripheral surface of the cylinder liner, and the refrigerant is inserted into the refrigerant passage. Cooling devices for internal combustion engines using so-called groove cooling have been known in the past, and the present applicant previously proposed a cooling device of this type as shown in FIG. −
No. 51701).

In FIG. 3, a plurality of annular grooves 3 having a rectangular cross section are formed at equal intervals in the axial direction of the cylinder liner 2 on the outer peripheral surface of the cylinder liner 2 fitted into the cylinder block 1. When the cylinder liner 2 is fitted into the bore of the cylinder block 1, the annular groove 3 forms an annular refrigerant passage with the inner peripheral surface 4 of the bore.

[0005] Furthermore, at positions where the cylinder liner 2 and the cylinder block 1 face each other, and where the cylinder liner 2 and the cylinder block 1
Vertical grooves 5a and 5b, 6a and 6b are formed in the axial direction (vertical direction) so as to communicate the plurality of annular grooves 3. Further, the cylinder block 1 is formed with inflow ports 7a and 7b that communicate with the vertical grooves 5a and 5b, respectively, and the vertical grooves 6a and 6b.
Outlets 8a and 8b are formed which communicate with each other, respectively.

The refrigerant pump 9 divides the refrigerant into two branches and sends out the refrigerant, one of which is supplied to the inlet 7a through the filter 10 with a high refrigerant pressure, and the other is supplied directly to the inlet 7b with a low refrigerant pressure. be done. The refrigerant supplied to the inlet 7a passes through the vertical groove 5a, is distributed to the annular groove 3 at the top of the cylinder, passes through the outer periphery of the cylinder liner 2, and then passes through the vertical groove 6a.
It flows out through the outlet 8a. The refrigerant supplied to the inlet 7b passes through the vertical groove 5b, is distributed to the annular groove 3 at the bottom of the cylinder, passes through the outer periphery of the cylinder liner 2, and then passes through the vertical groove 6.
b and flows out from the outlet 8b. Outlet 8a, 8b
The refrigerant flowing out is combined and circulated to the pump 9 through a radiator (not shown).

According to the above-mentioned proposed device, the combustion chamber generates
The heat transferred from the cylinder head to the cylinder liner 2 can be cooled by cooling the wall surface of the cylinder liner 2. Here, the wall surface of the cylinder liner 2 shows a heat input distribution in which the temperature is highest in the upper part of FIG. 3, which is closest to the combustion chamber, and the temperature decreases as it goes to the lower part.

Therefore, the flow rate of the refrigerant is adjusted to match this heat input distribution, and the flow rate of the annular groove 3 closest to the combustion chamber is set to be the maximum among the plurality of annular grooves 3, as shown by c in FIG. The further away from the cylinder liner 2, the smaller the flow rate in the annular groove 3 becomes necessary in order to uniformly cool the wall surface of the cylinder liner 2.

Therefore, in the above proposed device, the vertical grooves 5a,
When the diameters of 5b, 6a, and 6b are set to a predetermined value or more, Fig. 4
Although the refrigerant flow rate distribution between the plurality of annular grooves 3 is constant as shown by a in FIG. The flow rate of the annular groove 3 in the upper part can be made relatively larger than that of the other parts, and the heat input distribution c can be approximated somewhat.

0010

However, in the above proposed device, as shown in FIG. 4, the difference in flow rate between the annular groove 3 at the top and the annular groove 3 slightly below it is too large. , it is difficult to match the flow rate distribution to the heat input distribution c. The reason for this is that the connecting part between the refrigerant inlet 7a and the vertical groove 5a is perpendicular to each other, so that the refrigerant is not introduced by the refrigerant inlet 7a to the annular groove 3 at the top, which is on the extension of the refrigerant inlet 7a. In contrast, the refrigerant introduced through the refrigerant inlet 7a flows through the flow path at right angles to the second and subsequent lower annular grooves 3 from the top. As a result, the pressure loss due to bending is large,
This is because the refrigerant becomes difficult to flow. Therefore, in the above cooling device, the main flow of the refrigerant is as shown by the arrow in FIG.

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 device for an internal combustion engine that solves the above-mentioned problems by reducing pipe resistance due to bending of a refrigerant inlet.

0012

[Means for solving the problem] An annular groove formed along the circumferential direction of the cylinder liner on the outer periphery of the cylinder liner,
A plurality of annular grooves are provided in the axial direction of the cylinder liner, and each of the plurality of annular grooves extends in the axial direction of the cylinder liner and communicates with each other by first and second longitudinal grooves provided at different positions, A refrigerant inlet and a refrigerant outlet are communicated with the first and second longitudinal grooves at an angle, and at least the refrigerant flows through the communication connection between the refrigerant inlet and the first longitudinal groove. The side connecting portions are formed in a gentle manner.

[0013]

[Operation] Among the communication connection portions between the inflow port and the first vertical groove, at least the connection portion on the side where the refrigerant advances is formed smoothly, so that the refrigerant flowing out from the refrigerant inflow port flows into the first vertical groove. When the refrigerant is distributed and supplied to each of the plurality of annular grooves through the first vertical groove, the flow path is bent with less pipe resistance, and the refrigerant is also distributed to each of the annular grooves other than the first annular groove that is closest to the combustion chamber. There will be an influx.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a schematic structural diagram of an embodiment of a cooling system for an internal combustion engine according to the present invention, in which (A) is a plan view and (B) is a B- Cross-sectional view along line B, same figure (C
) is a sectional view taken along line CC in FIG. Figure 1 (
In A) to (C), an annular groove 13 formed along the circumferential direction of the cylinder liner 12 is formed on the outer peripheral surface 12a of the cylinder liner 12 fitted to the cylinder block 11.
A plurality of them are provided in the axial direction of the cylinder liner 12. In addition, the inner peripheral part of the cylinder block 11 and the cylinder liner 12
As shown in FIGS. 1A and 1B, vertical grooves 14 and 15 are formed on the outer circumferential surface of the cylinder liner 12, extending in the axial direction of the cylinder liner 12 between the plurality of annular grooves 13, and at positions facing each other. is formed. Therefore, the longitudinal grooves 14 and 15 allow the plurality of annular grooves 13 to communicate with each other. Further, the annular groove 13 and the inner circumferential surface 16 of the bore portion of the cylinder block 12 form an annular refrigerant passage as shown in FIG. 1(C).

Further, the refrigerant inlet 17 communicates with the vertical groove 14, and the refrigerant outlet 18 communicates with the vertical groove 15. The refrigerant inlet 17 and the refrigerant outlet 18 are arranged so that the annular groove 131 closest to the combustion chamber of the internal combustion engine is located on the extension line of the refrigerant inlet 17 and the refrigerant outlet 18, as shown in FIG. 1(B). ing.

Furthermore, in this embodiment, the connecting portion between the refrigerant inlet 17 and the vertical groove 14 on the side where the refrigerant advances has an arc shape as shown at 19 in FIG. 1(B). is formed. That is, whereas in the past, this communication connection part was a right angle, in this embodiment it is rounded.

Next, the operation of this embodiment will be explained. A refrigerant pumped by a pump (not shown) flows into the refrigerant inlet 17 . This refrigerant flows from the refrigerant inlet 17 into the vertical groove 14 as shown by X in FIG.
The water is branched into each of the following. The refrigerant travels inside the annular groove 13 in the direction indicated by Y in FIG.
After flowing along the outer circumferential surface of 2, it flows into the vertical groove 15, where it merges. The refrigerant that merges in the vertical groove 15 first advances upward, as shown by Z in FIG. 1(B), and then is guided to the refrigerant outlet 18 and flows out.

According to this embodiment, the refrigerant inlet 1
The refrigerant flowing into 7 flows into the annular groove 131 located closest to the combustion chamber, and due to the circular arc section 19 shown in Fig. 1(B), the refrigerant flows from the combustion chamber with significantly less pipe resistance than in the past. Since it also flows into the second and subsequent annular grooves, the flow rate flowing into the second and subsequent annular grooves increases compared to the conventional method.

Therefore, according to this embodiment, the flow rate distribution of the refrigerant flowing through the plurality of annular grooves 13 can be made to substantially match the heat input distribution shown by c in FIG. Can be done.

FIG. 2 shows a schematic sectional view of another embodiment of the device according to the invention. In the figure, the same components as those in FIG. In FIG. 2, the refrigerant inlet 21 communicates with the vertical groove 22, and is arranged at a height where the annular groove closest to the combustion chamber is located on the extension line thereof;
Also, the point that the vertical grooves 22 communicate between the plurality of annular grooves is the same as in the previous embodiment, but the shape of the communication connection between the refrigerant inlet 21 and the vertical grooves 22 is different from the previous embodiment.

That is, in this embodiment, the refrigerant inlet 21
Of the communication connection between the vertical groove 22 and the vertical groove 22, the side where the refrigerant advances (
A sloped portion 23 is formed at the communication connection portion on the lower side in the figure, and a similar sloped portion 24 is formed at the communication connection portion on the opposite side (upper side in the figure). As a result, in the case of this embodiment as well, it is possible to prevent a pressure drop due to bending of the flow path at the communication connection between the refrigerant inlet 21 and the vertical groove 22, and to optimize the refrigerant flow distribution between the annular grooves. can be achieved.

Note that the vertical grooves 14 and 15 do not have to be located opposite each other.

[0023]

As described above, according to the present invention, the flow path of the refrigerant from the refrigerant inlet can be bent with less pipe resistance, and the refrigerant can flow into each annular groove other than the one closest to the combustion chamber. As a result, the flow rate of each annular groove other than the one closest to the combustion chamber can be increased compared to the conventional method, which allows the refrigerant flow rate to match the heat input distribution of the cylinder liner more than before. It has features such as being able to obtain a uniform cooling distribution and cooling the cylinder liner wall surface more uniformly.

[Brief explanation of drawings]

FIG. 1 is a schematic block diagram of an embodiment of the device of the present invention.

FIG. 2 is a schematic cross-sectional view of another embodiment of the device according to the invention.

FIG. 3 is a sectional view of an example of a conventional device.

FIG. 4 is an explanatory diagram of the cylinder block heat input distribution and the refrigerant flow rate distribution according to the longitudinal groove diameter.

[Explanation of symbols]

11 Cylinder block 12 Cylinder liner 13 Annular groove 14, 15, 22 Vertical groove 17, 21 Refrigerant inlet 18 Refrigerant outlet 19 Arc part 23, 24 Slope part

Claims (1)

[Claims] 1. A plurality of annular grooves are provided in the axial direction of the cylinder liner on the outer periphery of the cylinder liner, and a plurality of annular grooves are formed along the circumferential direction of the cylinder liner in the axial direction of the cylinder liner. and communicated by first and second longitudinal grooves provided at different positions, respectively, and a refrigerant inlet and a refrigerant outlet are communicated with the first and second longitudinal grooves at an angle. A cooling device for an internal combustion engine, characterized in that, among the communication connection portions between the refrigerant inlet and the first vertical groove, at least the connection portion on the side where the refrigerant advances is formed in a gentle manner.