JPH04251657A - Method for providing continuous metallurgical connection between cylinder liner and cast forming crank case of internal combustion engine - Google Patents

Abstract

PURPOSE: To obtain the continuously intense metallurgical bond between a cylinder liner and a crankcase in an internal combustion engine. CONSTITUTION: A metal or alloy which is different from a metal contained in the material constituting the liner 2 and the crankcase and deposits the thin layer of the metal increasing the wettability of the liner 2 and the heat transfer coefficient between the liner 2 and the cast material and constitutes the crankcase around the liner 2 disposed in a mold 1, is cast on the outer surface of the cylinder liner 2.

Description

[Detailed description of the invention]

The present invention relates to a method of obtaining a continuous metallurgical bond between a cylinder liner and a cast forming the crankcase of an internal combustion engine.

In an internal combustion engine, each piston (made of an aluminum alloy) slides precisely in a cylindrical space provided in the engine's crankcase (generally made of cast iron, but also made of an aluminum alloy). do. The accuracy of such sliding is ensured by steel or cast iron segments or elastic piston rings arranged around the piston. Particularly in aluminum alloy crankcases, the friction of the piston ring on the inner wall of the cylinder causes wear on the inner wall of the cylinder, and after a certain period of time, such wear reduces the accuracy of sliding. , resulting in reduced engine performance.

To avoid this drawback, a liner made of a material with high wear strength, such as steel or other aluminum alloys, is inserted into the space of the cylinder. These liners are inserted into the engine crankcase after the engine crankcase is made by casting, either by heat fitting or by being placed in the mold as an insert during the casting process. In both cases, the coupling between the liner and the crankcase
ing) is achieved by mechanical gripping without continuity between materials. As a result, discontinuities between materials result in poor thermal conductivity, resulting in poor cooling of the inner surface of the cylinder (co
oling down). Furthermore, because of these discontinuities and because of the differences in thermal expansion coefficients between each material, the adhesion and mechanical hooking between the crankcase and liner is reduced after being subjected to repeated thermal cycling. , the crankcase and liner are individually separated and subject to mutual movement, and the quality of the surface finish on the inner surface of the liner deteriorates rapidly due to insufficient cooling.

The inventors have discovered that a suitable surface treatment of the cylinder liner results in a strong metallurgical bond between said liner and the cast that constitutes the crankcase of an internal combustion engine, and has led to the present invention. Ta. In particular, in the method according to the invention the standard requirements of welding operations (removal of surface impurities and oxides, intimate contact and coalescence between the materials to be joined) are met. However, such welding methods do not require external energy sources (heat, ultrasound, etc.);
It is very different from other methods in that the welding is done during casting. Additionally, metals that cannot be easily bonded by other methods can also be bonded by such welding methods. The method according to the invention provides a method for obtaining a continuous metallurgical bond between a cylinder liner and a cast forming the crankcase of an internal combustion engine, which is made of a material different from that of which the liner is made, by surface treatment by precipitation. The outer surface of the liner is coated with a metal that is different from the metal contained in the materials that make up the liner and the crankcase, which improves the wettability of the liner and the heat transfer coefficient between the liner and the cast materials. The method is characterized in that a thin layer of increasing metal is deposited and the metal or alloy forming the crankcase is cast around the liner placed in a mold.

Liners and casts are constructed of aluminum or magnesium, or aluminum alloys or magnesium alloys. However, they must have mutually different compositions. moreover,
The liner may be composed of a composite material containing alumina or magnesium or an aluminum alloy or a magnesium alloy as the metal matrix. Materials of this kind are constituted by a metallic phase (or alloy phase) surrounding and bonding to another phase (ceramic powder or fibers) which constitutes the reinforcement. Reinforcement provides a high degree of mechanical strength and stiffness and transfers stress on the matrix to the reinforcement. On the other hand, the matrix must be endowed with suitable properties depending on the intended use. The reinforcement material can be long ceramic fibers or short ceramic fibers (A
l2O3, SiC, Si3N4, BN, SiO2) or by ceramic whiskers (SiC, Si3N4
, B4C, Al2O3) or by non-metallic powder (S
iC, BN, Si3N4, B4C, SiO2 or Al2
O3). The method for preparing the composite material is as follows. - Dispersion of reinforcement in a molten matrix - Dispersion of reinforcement in a partially molten matrix - Powder metallurgy - Fiber metallurgy -
Layer compacting-infiltration composite materials are obtained directly or by subsequent machining/processing.

A thin layer (preferably 10 to 100
The metals (which must be different from those contained in the material and cast) are preferably Au, Ag, Cu, Ni, Pt, P
d, Cr, W, Ir, Mo, Ta, Nb, Os, Re,
Selected from Rh, Ru and Zr. Deposition of the thin layer of metal is preferably carried out by sputtering or electrochemical deposition methods. Various other chemical, physical, etc. methods known in the art for surface coating can be used. Examples include a plasma spray method, a laser deposition method, a thermal evaporation deposition method, a magneton deposition method, and a CVD (chemical vapor deposition) method. By using suitable coatings, the molten metal subjected to casting can sufficiently wet the metal materials or metal matrix composites to transfer heat to these materials and prevent the unavoidable formation on the surface of the materials. The oxide layer can be washed away and bonded directly to the metallic material, if used, or to the metal matrix, if a composite material is used.

[0007] After the material has been properly cleaned, coated, and placed within the casting die, casting operating parameters must be adjusted to provide a suitable flow of superheated molten metal over the surface of the material. The location of the material within the die is suitably selected and the shape of the ingress duct and egress duct within the die is such that the molten metal is cooled at low temperatures. It is important that the wall of material is suitably designed so that it can be covered, wetted and cleaned. Therefore, it is important to keep the following three parameters under control: material preheating temperature, metal (or alloy) casting temperature, and flux conditions. In either case, an excellent metallurgical bond is obtained between the material and the cast. The cylinder liner can be manufactured by techniques known in the art (e.g., gravity casting, pressure casting, die casting, squeeze casting, powder metallurgy, infiltration or blending), directly or by continuous machining with mechanical equipment or plastic processing (extrusion, lamination). or casting).

[0008]

[Examples] Next, some examples will be illustrated, but these are for further explaining the present invention, and are not intended to limit the present invention. Example 1 (test on laboratory scale) - outer diameter 50 mm, thickness 5 mm obtained by gravity casting
and a hypereutectic Al with a Si content of 17% and a height of 65 mm.
- The liner was formed by a tube made of Si alloy. - The outer surface of the liner was coated with a thin layer of gold by sputtering. - The material forming the cast is Al-S with a Si content of 9%.
i alloy. - The casting die is made of graphite. Figure 1 of the dice
Shown below. In the figure, numeral 1 is a graphite die,
2 is a liner, and 3 is a molten metal flow path. - The liner and die were preheated to 350°C. - The metal temperature of the cast is 700°C. - The volume of the cast material is approximately 400 cm3. - Casting was carried out by push casting.

Example 2 (Laboratory Scale Test) - A liner was formed by a composite tube obtained by gravity casting with an outer diameter of 50 mm, a thickness of 5 mm and a height of 65 mm. - The composite material was obtained by infiltration and consists of a matrix of eutectic Al-Si alloy with a Si content of 13% and a Si
It is composed of 55% by volume of reinforcing material of C powder (average diameter of powder particles 20 μm). - The outer surface of the liner was coated with a thin layer of gold by sputtering. - The material forming the cast is Al-S with a Si content of 9%.
i alloy. - The casting die is as shown in Figure 1 and is made of graphite. - The liner and die were preheated to 300°C. - The metal temperature of the cast is 650°C. - The volume of the cast material is approximately 400 cm3. - Casting was carried out by push casting.

Example 3 (Tests on an Industrial Scale) - Tests were conducted using industrial equipment for casting four-cylinder engine crankcases. - The liner is obtained by extrusion and is formed from a composite tube with an outer diameter of about 95 mm, a thickness of about 5 mm and a height of about 130 mm. - Composite material obtained by infiltration and dilution, S
Matrix of eutectic Al-Si alloy with i content 13% and SiC powder (average diameter of powder particles 20 μm) 25% by volume
It consists of reinforcing material. - The outer surface of the liner was coated with a thin layer of gold by sputtering. - The material forming the cast is Al-Si with a Si content of 9%.
It is an alloy. - Industrial casting dies are made of cast iron. - The liner was preheated to 300°C. - The temperature of the cast metal is approximately 700°C. - The volume of the cast material is approximately 10 dm3. - Casting was carried out by push casting.

Example 4 (Tests on an Industrial Scale) - Tests were conducted using industrial equipment for casting four-cylinder engine crankcases. - The liner is obtained by extrusion and is formed from a composite tube with an outer diameter of about 95 mm, a thickness of about 5 mm and a height of about 130 mm. - The composite material was obtained by mixing and had a Si content of 9
% of eutectic Al-Si alloy matrix and 15% by volume of SiC powder (average diameter of powder particles 20 μm) reinforcement. - The outer surface of the liner was coated with a thin layer of gold by sputtering. - The material forming the cast is Al-Si with a Si content of 9%.
It is an alloy. - Industrial casting dies are made of cast iron. - The liner was preheated to 300°C. - The dice were preheated to approximately 370°C. - The temperature of the cast metal is approximately 700°C. - The volume of the cast material is approximately 10 dm3. - Casting was carried out by push casting.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a casting die used in the present invention.

[Explanation of symbols]

1 Dice 2 Liner 3 Molten metal flow path

Claims (16)

[Claims] 1. A method for obtaining a continuous metallurgical bond between a cylinder liner and a cast forming the crankcase of an internal combustion engine, which is made of a material different from that of which the liner is made, comprising: applying a surface treatment by precipitation; and a metal on the outer surface of the liner that is different from the metal contained in the materials making up the liner and crankcase, increasing the wettability of the liner and the coefficient of heat transfer between the materials of the liner and the cast. of the casting for forming the cylinder liner and crankcase of an internal combustion engine, characterized in that the metal or alloy forming the crankcase is cast around the liner placed in a mold. A method of obtaining a continuous metallurgical bond between. 2. The method according to claim 1, wherein the crankcase is made of aluminum or magnesium, or an alloy of aluminum or magnesium, between a cylinder liner and a cast forming a crankcase of an internal combustion engine. How to obtain a continuous metallurgical bond. 3. The method of claim 1, wherein the liner is comprised of aluminum or magnesium, or an alloy of aluminum or magnesium, between a cylinder liner and a cast forming a crankcase of an internal combustion engine. A method of obtaining a continuous metallurgical bond. 4. The method according to claim 1, wherein the liner is composed of a composite material containing aluminum or magnesium or an alloy of aluminum or magnesium as a matrix. A method of obtaining a continuous metallurgical bond between casts that form a . 5. The method according to claim 4, wherein the liner is made of a composite material containing a non-metallic powder selected from SiC, BN, Si3N4, B4C, SiO2 or Al2O3 as a reinforcing material. A method of obtaining a continuous metallurgical bond between the cylinder liner and the casting that forms the crankcase of an internal combustion engine. 6. The method of claim 4, wherein the liner is SiC, Si3N4, B4C, SiO2 or Al.
A method for obtaining a continuous metallurgical bond between a cylinder liner and a cast forming the crankcase of an internal combustion engine, which is composed of a composite material containing as reinforcement ceramic whiskers selected from 2O3. 7. The method of claim 4, wherein the liner is composed of a composite material containing as reinforcement material long or short ceramic fibers selected from SiC, BN, Si3N4, B4C, SiO2 or Al2O3. A method of obtaining a continuous metallurgical bond between the cylinder liner and the casting that forms the crankcase of an internal combustion engine. 8. The method according to claim 5, 6 or 7,
A cast forming cylinder liner and crankcase of an internal combustion engine, wherein said liner is composed of a composite material containing said powder, whiskers or long or short ceramic fibers as reinforcement in an amount of 10 to 60% by weight. A method of obtaining a continuous metallurgical bond between 9. The method according to claim 1, wherein the metal deposited on the outer surface of the liner is Au, Ag, Cu,
Ni, Pt, Pd, Cr, W, Ir, Mo, Ta, Nb
, Os, Re, Rh, Ru and Zr, a method for obtaining a continuous metallurgical bond between a cylinder liner and a cast forming the crankcase of an internal combustion engine. 10. A method as claimed in claim 1, in which the deposition of the thin layer of metal is carried out by sputtering to obtain a continuous metallurgical bond between the cylinder liner and the cast forming the crankcase of an internal combustion engine. 11. The method of claim 1, wherein the deposition of said thin layer of metal is carried out by an electrochemical deposition method, a continuous metallurgical bond between a cylinder liner and a cast forming a crankcase of an internal combustion engine. How to get. 12. A method as claimed in claim 1, characterized in that the deposition of the thin layer of metal is carried out by a chemical deposition method, providing a continuous metallurgical bond between a cylinder liner and a cast forming a crankcase of an internal combustion engine. How to get it. 13. The method of claim 1, wherein the deposition of the thin layer of metal is performed by plasma spraying, thermal evaporation, carbon
A method of obtaining a continuous metallurgical bond between the cylinder liner and the casting forming the crankcase of an internal combustion engine, carried out by VD (Chemical Vapor Deposition) or by laser or magneton deposition. 14. The method of claim 1, wherein the liner is formed directly by gravity casting, pressure casting, die casting or squeeze casting, powder metallurgy, infiltration or blending, or by machining or A method of obtaining a continuous metallurgical bond between the cylinder liner and the cast forming the crankcase of an internal combustion engine, obtained by mechanical plastic processing (extrusion, lamination or casting). 15. The method of claim 4, wherein the composite material is prepared by dispersing a reinforcing material in a matrix in a molten state, or by dispersing a reinforcing material in a matrix in a partially molten state, using a powder metallurgy method. , a method of obtaining a continuous metallurgical bond between the cylinder liner and the cast forming the crankcase of an internal combustion engine, which is obtained by metal coating the fibers, layer compression method or infiltration. 16. The method of claim 1, wherein the thin layer of metal deposited on the outer surface of the liner is between 10 and 100 nm thick between a cylinder liner and a cast forming a crankcase of an internal combustion engine. How to obtain a continuous metallurgical bond.