JPH0236925Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] This invention relates to a seal structure for a wet type cylinder liner.

[Prior art]

Diesel engine cylinders are exposed to higher temperatures and pressures than gasoline engines, so liners are fitted into the cylinders to improve quality and wear resistance, as well as to facilitate maintenance.

There are two types of liners: dry liners whose outer peripheral surface does not come in direct contact with cooling water, and wet liners whose outer peripheral surface directly contacts cooling water.In addition to forming a combustion chamber with the piston and cylinder head, this liner
It prevents the piston from wobbling as it reciprocates, and also serves to dissipate heat from the piston, which has become hot due to combustion, into the surrounding cooling water.

By the way, recently, in order to improve engine performance by reducing the debris volume in the cylinder and to reduce oil consumption, for example, a pressure ring 2 is installed at the top of the piston 1 as shown in FIG. There is a demand for a so-called high top ring, in which the mounting position H of the ring is set upward.

However, by implementing the high top ring, the pressure ring 2 is installed at a position shifted from the cooling position by the water jacket 4 formed in the cylinder block 3, and the heat dissipation conditions of the pressure ring 2 are changed. The problem is that it will get tougher.

That is, since the pressure ring 2 is provided at a position away from the water jacket 4, the amount of heat transfer is reduced, and as a result, the wear resistance of the pressure ring 2 is reduced, and its function as a piston ring (gas sealing performance) is reduced. However, there was a problem in that the amount of oil consumed was significantly reduced (increased oil consumption, reduced blow-by gas flow rate, etc.).

In order to prevent the above-mentioned reduction in the amount of heat transfer of the pressure ring 2, it is conceivable to extend the volume of the water jacket 4 formed in the cylinder block 3 upward. However, if the volume of the water jacket 4 is extended upward, the cylinder block 3
As the thickness of the upper part of the side wall becomes thinner, there is a problem in that it becomes difficult to attach a sealing material 6 such as a packing or an O-ring provided at the abutting portion between the cylinder liner 5 and the cylinder block 3.

In FIG. 1, 7 is a gasket, and 8 is a cylinder head.

[Purpose of invention]

This idea was devised by focusing on the conventional problems, and its purpose is to increase the volume of the water jacket provided around the cylinder upwards to improve heat dissipation from the pressure ring of the piston. To provide a sealing structure for a cylinder liner that can sufficiently exhibit sealing performance between the flange of the cylinder liner and the cylinder block in the upper part of the water jacket.

[Structure of the idea]

In order to achieve the above object, the seal structure of the cylinder liner of the present invention has a structure in which a water jacket hole surrounding the cylinder is formed in the cylinder block, and a cylinder liner is provided at the upper edge of the water jacket hole. A stepped portion is provided to receive the flange of the liner, a recessed portion surrounding the cylinder is provided on the lower surface of the flange, and a sealing material is attached to the recessed portion to seal between the upper surface of the flange of the cylinder liner and the cylinder head. A head gasket is interposed between the lower surface and the lower surface.

[Example of idea]

Embodiments of this invention will be described below based on the accompanying drawings.

In the following explanation, the same components as those of the conventional example explained in FIG.

Figure 2 shows a cross-sectional view of a wet cylinder liner in a multi-cylinder internal combustion engine implementing this invention.
1 is a piston, 5 is a pressure ring, 3 is a cylinder block, 4 is a water jacket, 5 is a cylinder liner, and the pressure ring 2 is located at a predetermined distance from the top of the piston 1 in order to reduce the debris volume in the combustion chamber D. It is provided at h.

Further, the volume of the water jacket 4 is configured to be near the top dead center position of the pressure ring 2, and the flange portion 5a of the cylinder liner 5 is made thin so that the cooling water W can reach a high position.

Cooling water W in the water jacket 4 leaks between the tip of the adjacent flange part 5a of the cylinder liner 5 and the stepped part 3a formed in an inner flange shape projecting from the upper part of the water jacket hole 4a. A sealing material 6 such as a gasket or an O-ring is provided to prevent this from coming out.

The sealing material 6 is the flange portion 5 of the cylinder liner 5.
The sealing material 6 fitted into the recessed portion 9 and the sealing material 6 and the top portion 3a of the cylinder block 3 are fitted into a recessed portion 9 formed on the lower surface of the tip end of the cylinder a.
are in close contact with each other to prevent leakage of the cooling water W.

FIG. 3 shows a second embodiment of this invention, in which a partition wall 5b is provided at the portion where adjacent cylinder liners 5 are closest to each other, and a stepped portion 3a is formed so that the upper surface of the cylinder block 3 is continuous. This is what I did. In the case of the second embodiment, similarly to the first embodiment, a recess 9 is provided on the lower surface of the tip of the flange 5a, and a sealing material 6 is interposed in the recess 9 to prevent leakage of the cooling water W. This is what I did.

With the above configuration, this device increases the amount of heat transferred from the piston 1 to the pressure ring 2 to the cylinder liner 5 to the cooling water W in the water jacket 4 while maintaining the sealing performance of the cooling water W. This stabilizes the oil film inside the cylinder and reduces oil consumption, and by placing the pressure ring 2 at a higher position than before, the dead space is reduced and engine performance is improved. This is possible.

[Effect of idea]

This invention, as described above, seals the upper end of the water jacket formed around the cylinder liner with a sealing material attached to the recess provided on the lower surface of the cylinder liner collar. The upper end of the jacket can be formed as high as possible to expand the volume of the water jacket upwards and improve heat dissipation from the pressure ring of the piston. Therefore, it is possible to prevent an increase in heat load due to the piston having a high top ring.

Further, since the sealing material is tightened using the tightening force of the head bolt, high sealing performance can be obtained even if the thickness of the stepped portion is made thin due to the upward expansion of the water jacket. Therefore, the various functions of the piston ring (gas sealing performance, saving oil consumption, suppressing blow-by gas flow rate, etc.) can be effectively exhibited, and engine performance can be significantly improved.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing a conventional cylinder liner seal structure, Fig. 2 is a sectional view of a seal structure implementing this invention, and Fig. 3 is a sectional view showing another embodiment.
It is a figure similar to the figure. 3... Cylinder block, 3a... Step portion, 4
... Water jacket, 4a ... Water jacket hole, 5 ... Cylinder liner, 5a ... Flange, 6 ... Sealing material, 9 ... Recess, W ... Cooling water.

Claims (1)

[Scope of utility model registration request] A water jacket hole surrounding the cylinder is bored in the cylinder block, a stepped portion is provided on the upper edge of the water jacket hole to receive the flange of the cylinder liner, and a recessed portion surrounding the cylinder is provided on the lower surface of the flange. A sealing structure for a cylinder liner, in which a sealing material for sealing between the recess and the stepped portion is installed, and a head gasket is interposed between the upper surface of the flange of the cylinder liner and the lower surface of the cylinder head.