JPH0510205A - Cooling device for internal combustion engine - Google Patents

Abstract

PURPOSE:To reduce mirror-face wear of the inner wall of a cylinder line, suppress the piston striking sound, and reduce electrolytic corrosion between the cylinder liner and cylinder block. CONSTITUTION:A groove is formed at the periphery of a cylinder liner 11 fitted in a cylinder block 20, and refrigerant is allowed to flow through a passage formed by this groove and the internal circumference of the cylinder block bore part 21 so as to cool the cylinder liner 11. Therein the dia. of the outside surface 13 of the cylinder liner 11 shall be smaller than the dia. of the inside surface of the bore part 21 so as to provide a gap good small relative to the radial direction depth of the groove between the liner 11 outside surface 13 and the bore surface.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal combustion engine cooling device for cooling a cylinder of an internal combustion engine.

[0002]

2. Description of the Related Art Conventionally, as disclosed in Japanese Utility Model Laid-Open No. 63-168242, there is a cooling device for cooling an internal combustion engine by providing a spiral or annular refrigerant passage groove on the outer periphery of a cylinder liner to circulate the refrigerant.

As shown in FIG. 3, in this conventional cooling device, a groove 4 having a rectangular cross section is spirally formed on an outer peripheral surface 3 of a cylinder liner 1 having a flange portion 2 at its upper end. The cylinder liner 1 is fitted with its outer peripheral surface 3 in contact with the bore inner peripheral surface 6 of the cylinder block 5, and the groove 4 and the bore inner peripheral surface 6 form a spiral refrigerant passage 7.

[0004]

In the conventional cooling device, since the outer peripheral surface 3 of the cylinder liner 1 is in contact with the inner peripheral surface 6 of the bore of the cylinder block 5, the side pressure of the piston or the combustion pressure causes the cylinder liner 1 to move. There is a problem that the cushioning effect when the inner wall is deformed is small, the inner wall of the cylinder liner 1 honed to retain the engine oil is mirror-polished, the engine oil retaining property is deteriorated, and the piston striking sound is large. was there.

Further, when the cylinder liner 1 is cast iron and the cylinder block 5 is aluminum, there is a problem that electrolytic corrosion occurs at the contact surface between the cylinder liner 1 and the cylinder block 5, which are different metals.

The present invention has been made in view of the above points, and by providing a gap between the outer peripheral surface of the cylinder liner and the inner peripheral surface of the bore portion of the cylinder block, mirror wear of the inner wall of the cylinder liner and piston stroke are achieved. An object of the present invention is to provide a cooling device for an internal combustion engine that suppresses noise and reduces electrolytic corrosion between the cylinder liner and the cylinder block.

[0007]

In a cooling device for an internal combustion engine of the present invention, a groove is formed on an outer peripheral surface of a cylinder liner fitted in a cylinder block, and the groove and the inner peripheral surface of a bore portion of the cylinder block are formed. In a cooling device for an internal combustion engine that cools the cylinder liner by circulating a refrigerant in a refrigerant passage, the outer diameter of the cylinder liner and the outer diameter of the cylinder liner are made smaller than the inner diameter of the bore portion of the cylinder block. A gap that is sufficiently smaller than the radial depth of the groove is provided between the inner peripheral surface of the bore portion and.

[0008]

In the present invention, since there is a gap between the outer peripheral surface of the cylinder liner and the inner peripheral surface of the bore portion of the cylinder block and there is no contact, the cushioning effect of the deformation of the cylinder liner due to the side pressure of the piston is increased. . In addition, the contact area between the cylinder liner and the cylinder block, which are different metals, is significantly smaller than in the conventional case.

[0009]

1 is a sectional view of an embodiment of the device of the present invention, FIG.
Shows a partially enlarged sectional view thereof.

In both figures, 11 is a cylinder liner made of cast iron and has a cylindrical shape having a flange portion 12 at the upper end thereof.
A plurality of annular grooves 14 having a rectangular cross-section and a radial depth of several millimeters are formed at equal intervals in the axial direction except the outer peripheral surface 13. The annular grooves 14 are communicated with each other by a communication groove (not shown) formed at a position rotated 180 degrees in the circumferential direction of the cylinder liner 11.

A curved surface is formed between the outer peripheral surface 13 of the cylinder liner 11 and the side wall 14a of each annular groove 14 by rounding.

An annular groove 15 for holding an O-ring is formed near the lower end of the cylinder liner 11.

A cylinder block 20 made of an aluminum alloy in which the cylinder liner 11 is fitted is provided with a bore portion 21 having a diameter slightly larger than the outer diameter of the cylinder liner 11, for example, several tens of microns, and the upper end of the bore portion 21. An annular notch 22 for fitting the flange 12 of the cylinder liner 11 is formed in the portion.

O in the annular groove 15 of the cylinder liner 11
The ring 25 is attached, the cylinder liner 11 is inserted into the bore portion 21 of the cylinder block 21, and the flange portion 12 is fitted into the cutout portion 22 to fix the cylinder liner 11.

Since the inner diameter of the bore portion 21 is slightly larger than the diameter of the outer circumferential surface 13 of the cylinder liner 11, the entire circumference of the outer circumferential surface 13 of the cylinder liner 11 and the bore portion 2 are formed.
A gap 30 is formed between the inner peripheral surface of the first plate 1 and the inner peripheral surface of the first plate 1. This gap 3
0 is several tens of microns, which is sufficiently smaller than the radial depth of the annular groove 14 of the cylinder liner 11 of several millimeters. Therefore, most of the refrigerant flows along the annular groove 14 through the refrigerant passage formed by the annular groove 14 of the cylinder liner 11 and the bore portion 21 of the cylinder block 20, and passes through the gap 30 between the adjacent annular grooves 14 to pass the refrigerant. Can be ignored.

Thus, the outer peripheral surface 1 of the cylinder liner 11
Since 3 is not in contact with the inner peripheral surface of the bore portion 21 of the cylinder block 20, the cushioning effect is large when the inner wall of the cylinder liner 11 is deformed by the side pressure of the piston or the combustion pressure. Therefore, it is possible to suppress mirror surface wear of the inner wall of the cylinder liner 11, prevent deterioration of engine oil retention, and suppress piston striking sound.

Further, in the cylinder liner 11, only the flange portion 12 is in contact with the cutout portion 22 of the cylinder block 20, so that the contact area between the cylinder liner 11 and the cylinder liner block 20 is reduced as compared with the conventional case. The occurrence of electrolytic corrosion can be reduced.

Further, since the curved surface having a roundness is formed between the outer peripheral surface 13 of the cylinder liner 11 and the side wall 14a of the annular groove 14, the inner wall of the cylinder liner 11 is deformed by the side pressure or combustion pressure of the piston. Even if the outer peripheral surface 13 contacts the inner peripheral surface of the bore portion 21 of the cylinder block 20, the inner peripheral surface of the bore portion 21 is prevented from being damaged.

In the above embodiment, the cylinder liner 1
Although the annular groove 14 is formed on the outer peripheral surface 13 of No. 1, the spiral groove may be formed instead of this, and the present invention is not limited to the above embodiment.

[0020]

As described above, according to the cooling apparatus for an internal combustion engine of the present invention, mirror surface wear of the inner wall of the cylinder liner and piston striking noise can be suppressed, and electrolytic corrosion between the cylinder liner and the cylinder block can be reduced. It is possible and practically extremely useful.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of the device of the present invention.

FIG. 2 is a partially enlarged cross-sectional view of FIG.

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

[Explanation of symbols]

 11 Cylinder Liner 12 Collar 13 Outer Surface 14 Annular Groove 14a Side Wall 20 Cylinder Block 21 Bore 22 Notch

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kiyoshi Nakanishi 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Automobile Co., Ltd.

Claims (1)

Claim: What is claimed is: 1. A groove is formed on the outer peripheral surface of a cylinder liner fitted in a cylinder block, and a refrigerant is introduced into a refrigerant passage formed by the groove and an inner peripheral surface of a bore portion of the cylinder block. In a cooling device for an internal combustion engine that circulates to cool a cylinder liner, the diameter of the outer peripheral surface of the cylinder liner is set to be smaller than the diameter of the inner peripheral surface of the bore portion of the cylinder block, and the outer peripheral surface of the cylinder liner and the bore of the cylinder block. A cooling device for an internal combustion engine, characterized in that a gap sufficiently smaller than the radial depth of the groove is provided between the inner peripheral surface of the portion and the inner peripheral surface.