JPH0629531B2 - Internal combustion engine - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an internal combustion engine, and more particularly to a lubricating oil system provided with measures for preventing oil deterioration of the internal combustion engine.

[Prior art]

In an internal combustion engine, a lubricating oil system is provided to supply and circulate the lubricating oil to the sliding and sliding parts inside the internal combustion engine to protect each part from friction and overheating, and to maintain a long service life. In addition to the influence of heat, the lubricating oil is inevitably deteriorated because water, fuel, combustion products, and further metal abrasion powder are mixed.

Further, it is known that such deterioration of oil is promoted by the catalytic action of a metal or the like in contact with the oil.

FIG. 2 shows an example of a lubricating oil system in a conventional internal combustion engine, where 1 is an oil pan for storing oil, and 2 is an oil pan.
Is an oil pump driven by a coaxial crankshaft 3, and 4 is an oil filter. The lubricating oil sucked up by the oil pump 2 from the oil pan 1 through the strainer 5 passes through the filter 4 and the main oil gallery 6
To the crankshaft 3, piston 7
And lubricate each part of the cylinder through the path indicated by the arrow.

Further, the lubricating oil sent from the main gallery 6 to the cylinder head 10 through the supply passage 9 of the cylinder block 8 receives the bearing portion of the camshaft 11 and the rocker shaft 12.
After lubricating the periphery of the oil return hole 13 and the return passage
It is returned to the oil pan 1 through 14.

However, in such a conventional internal combustion engine,
No special measures have been taken to prevent the deterioration of the oil in the lubricating oil system.Since the metal itself is generally exposed at the part that comes into contact with the oil and the surface of the oil passage, With respect to the deterioration of oil due to the oxidation reaction, etc., these metal parts act as catalysts and tend to accelerate the deterioration.

FIGS. 3 and 4 show examples of experimental values in which such an oxidation reaction of oil was measured depending on the type and presence of a catalytic metal, respectively, and the oxidation (mgKOH / g )It is shown.

That is, as is clear from these figures, in the case of an internal combustion engine, when water is present in the lubricating oil passage or the like in a cylinder block or cylinder head where the temperature is relatively high, the catalytic action of iron Fe or copper Cu is obtained. It can be seen that the acid value of oil rapidly increases.

〔Purpose〕

The object of the present invention is made in view of such conventional problems, and it is an object of the present invention to provide an internal combustion engine capable of preventing a catalytic action in a lubricating oil system and thereby suppressing deterioration of oil. is there.

[Configuration of the Invention] In order to achieve such an object, the present invention provides a surface of a lubricating oil system other than a sliding contact surface including a surface of a passage wall of a lubricating oil passage formed in a cylinder block and a cylinder head. It is characterized by being coated with a resin-based or ceramic-based non-metal material.

Embodiments Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1A and FIG. 1B show an embodiment of the present invention, in which the hatched portion shows the range covered by the non-metallic material in the present invention. That is, in the present invention, the lubricating oil passage of each part including the main oil gallery 6, the supply passage 9 and the return passage 14 and the wall surface of each member which the lubricating oil or the lubricating oil vapor comes into contact with are made of non-metallic resin such as fluorine. Alternatively, it is formed by the non-metal material 20 itself such as ceramic or its coating.

When forming such a covering material, for example, in the case of a lubricating oil passage or the like, first, a resin or a ceramic which is dissolved by using a solvent after machining is poured, and appropriately adhered to a wall surface and dried. Alternatively, the diameter of the passage, etc. may be processed to be slightly larger, the resin or ceramic may be attached, dried, and then processed to the conventional size. Which of these is used depends on the nature of the material to be coated. It may be selected appropriately according to the place where the coating is applied.

On the other hand, the piston ring 7A of the piston 7, the piston skirt portion 7B, the cylinder liner 8A, and the cam (not shown) attached to the camshaft 11 have sufficient wear resistance as long as they are a sliding contact portion or a portion corresponding thereto. Since various conditions such as heat resistance must be taken into consideration, and therefore no coating is provided, in that case, a material that does not easily adhere to the coating should be applied in advance to the entire surface for coating. After that, the coating of this portion may be peeled off, or a conventional coating may be applied to the entire surface, and then the coating of this portion may be cut and removed by machining.

In the internal combustion engine configured as described above, when the lubricating oil is circulated along the circulation path as described above, the wall surface of the lubricating oil passage and the surface of the lubricating oil contact portion are formed of the non-metallic material 20. Therefore, it is possible to remarkably suppress the deterioration of the oil without prolonging the oil's oxidation catalyst action, and to prolong the life of its replacement.

〔effect〕

As described above, according to the present invention, the surface of the lubricating oil system other than the sliding / sliding contact surface including the surface of the passage wall of the lubricating oil passage formed in the cylinder block and the cylinder head is made of resin or Since it is coated with a ceramic-based non-metallic material, it is possible to suppress the metal catalytic action that promotes the deterioration of oil in the parts where the temperature is relatively high, and to suppress the deterioration speed of oil significantly compared to the conventional case. Therefore, it is possible to contribute to extending the life of oil exchange.

[Brief description of drawings]

FIG. 1A is a schematic view showing an arrangement range of a non-metallic material in a lubricating oil system of an internal combustion engine of the present invention as an example, FIG. 1B is a schematic view of a part of FIG. 1A seen from its side, and FIG. 2A is FIG. 2B is a schematic view showing an example of a lubricating oil system in a conventional internal combustion engine, FIG. 2B is a schematic view of a part of FIG. 2A seen from the side, and FIGS. 3 and 4 show the oxidation reaction of oil by a metal catalyst. It is a curve figure and a bar chart which show an example of each tendency which is promoted, respectively. 1 …… Oil pan, 2 …… Oil pump, 3 …… Crankshaft, 4 …… Oil filter, 5 …… Strainer, 6 …… Main oil gallery, 7 …… Piston, 7A …… Piston ring, 7B …… Piston skirt, 8 …… Cylinder block, 8A …… Cylinder liner, 9 …… Supply passage, 10 …… Cylinder head, 11 …… Camshaft, 12 …… Rocker shaft, 13 …… Oil return hole, 14 …… Return Passage, 20 …… Non-metallic material.

Claims (1)

[Claims] 1. A surface of a lubricating oil system other than a sliding / sliding contact surface including a surface of a passage wall of a lubricating oil passage formed in a cylinder block and a cylinder head is covered with a non-metallic material of resin or ceramic. An internal combustion engine characterized by the above.