KR100828803B1 - Method for manufacturing aluminium cylinder block with aluminium liner - Google Patents

Abstract

An object of the present invention is to provide a method for manufacturing an aluminum liner that minimizes the interbore spacing of an engine block and enables a high pressure casting process by applying a high-quality material to only a major part of an engine block structure. By manufacturing individual cylindrical liners in an integrated structure using the over-processed Al-Si alloy used for the block, the reason for applying the aluminum liner to reduce the weight of the engine is not a simple difference in density, but the weight and compactness of the engine structure. The present invention is intended to provide a method for manufacturing an integrated aluminum liner for a lightweight engine block using an over-processed Al-Si alloy that can be applied to an aluminum block currently in mass production and also applied to a magnesium block that is attracting attention as a lightweight engine block.

Aluminum Liner, Cylinder Block, Lightweight / Camping, Al-Si Alloy

Description

Method for manufacturing aluminum cylinder block including integral aluminum liner using over-process Al-Si alloy {Method for manufacturing aluminum cylinder block with aluminum liner}

1 is a schematic view showing the structure of the engine block interbore;

Figure 2 is a micrograph showing the microstructure of the over-process Al-Si material,

3 is a schematic diagram illustrating the present invention and a conventional aluminum liner,

Figure 4 is a schematic view of the aluminum liner bore surface sliding surface.

The present invention relates to a method for manufacturing an integrated aluminum liner for a lightweight engine block using an over-process Al-Si alloy, and more particularly, to a form and a manufacturing process of an aluminum liner, which is increasing in demand for lightening an automobile engine. By integrating the aluminum liner structure, which has an independent cylindrical shape for each combustion chamber of the in-line or V-type engine, into three or four units of adjacent combustion chambers, the engine length can be shortened to achieve engine compactness and light weight. Method for manufacturing integrated aluminum liner for lightweight engine block using over-processed Al-Si alloy to reduce thermal load of interbore part, improve stiffness of entire engine block and improve dimensional stability of aluminum engine block under high pressure casting will be.

The engine block, a major automobile component, is constantly being demanded to be lightweight due to the improvement of fuel efficiency and environment, and the improvement of driving performance by optimizing the weight ratio before and after the vehicle.In addition, the engine block has secured rigidity and miniaturization (compact size) to cope with high engine power and layout optimization. Is being asked.

The main dimensions of the engine block are the cylinder bore diameter, the stroke length, and the interbore spacing. In particular, the interbore spacing is the spacing between the bore, which is the sum of the liner thickness and the thickness of the block portion between the liners. Although the engine becomes compact, at least 6 mm clearance is required to maintain the airtightness of the head gasket and to form a local coolant passage to cope with the heat load of the interbore due to the high output of the engine.

In the past, cylinder blocks were made of thermally stable cast iron castings, but for gasoline engines, most engine blocks were replaced with aluminum for gasoline engines, and the manufacturing process also applied a high-productivity die casting method in gravity casting. However, if the production volume is not high, the low pressure casting method, which is easy and simple to produce and has excellent casting quality, is used.

Cast iron liners or aluminum liners are applied to aluminum blocks. Recently, the application of aluminum liners is increasing due to the importance of weight reduction and the problems of bore heat deformation and thermal conductivity.

Cases of aluminum liners, which are mainly applied so far, can be summarized as shown in Table 1 below, but they are mainly applicable to high pressure casting processes, can reduce production costs, and achieve lightweight / compact engine structures. It is necessary to establish the technology that can be used.

Interbore spacing, one of the main dimensions mainly affecting engine block weight / compactness, is at least 6 mm in order to maintain the gasket airtightness of the cylinder head and to cope with thermal load due to high engine power as shown in FIG. 1. It is necessary to secure the above gap.

Therefore, the cylindrical aluminum liner currently applied to the aluminum engine block secures a gap of 8.5 mm to 11 mm, while the interbore integrated structure is secured by low pressure casting, and the mono block has a gap of 6 to 6.5 mm. .

Accordingly, the present invention is to provide a method for manufacturing an aluminum liner that minimizes the interbore spacing of the engine block, and enables high pressure casting process by applying a high-quality material to only the major parts of the engine block structure. By manufacturing individual cylindrical liners in one-piece structure using over-processed Al-Si alloys used in aluminum monoblocks, the reason for the application of aluminum liners for lighter engines is not a simple difference in density, but a lighter / compact engine structure. To provide a method for manufacturing an integrated aluminum liner for a lightweight engine block using an over-processed Al-Si alloy that can be applied to an aluminum block in mass production and to a magnesium block that is attracting attention as a lightweight engine block in the future. There is this.

In order to achieve the above object, the present invention provides an A390 alloy (Al-17% Si-4Cu) material, and a cylindrical liner applied to an inline four-cylinder engine. In case of the liner, a liner having an integral structure in which three liners are connected to one structure is manufactured, and four or three liners are formed by a low pressure casting method by injecting A390 alloy (Al-17% Si-4Cu) melt into the mold. Manufacturing a liner of a unitary structure connected to the structure, and inserting the liner of the unitary structure when the aluminum cylinder block is cast by high pressure casting, and integrally forming the liner of the unitary structure with the aluminum cylinder block. It provides an aluminum cylinder block manufacturing method comprising an integral aluminum liner using an over-process Al-Si alloy.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

3 is a schematic view for comparing the present invention and the existing aluminum liner.

The aluminum liner according to the present invention uses an A390 alloy material, and is less advantageous in terms of bore deformation and residual stress because the difference in thermal expansion with aluminum is smaller than that of the cylindrical aluminum liner by the rapid solidification method. As shown in Fig. 4, the primary Si particles crystallized in the liquid phase may play a major role in improving the sliding surface formation and wear resistance at the liner surface.

On the other hand, low pressure casting is a technique in which a single molten metal is slowly injected from a lower part of a mold to a low pressure to coagulate. This low pressure casting method mainly produces less casting defects and foreign substances such as oxides, and enables precise manufacturing of castings. It is mainly used for manufacture of a cylinder head, a wheel, etc.

First, in the case of a cylindrical liner applied to a series four-cylinder engine, four liners are manufactured, and in the case of a cylindrical liner applied to a V6 type engine, three liners are manufactured to form a liner having an integrated structure.

For example, A390 alloy (Al-17% Si-4Cu) molten metal is injected into a mold and four or three liners are connected to one structure by a low pressure casting method in which a casting is removed from the mold after solidifying the molten metal in the mold. Cast liner of unitary structure.

Next, the liner of the integral structure manufactured as described above is placed in the high pressure casting apparatus for manufacturing the aluminum cylinder block to manufacture the integral aluminum cylinder block and liner.

That is, when the aluminum cylinder block is cast by high pressure casting, the liner of the integrated structure is inserted to integrally mold the aluminum cylinder block and the integrated structure of the liner.

In the case of the cylindrical aluminum liner currently applied to the aluminum engine block, since the interbore portion is divided into a liner and an aluminum block, an interval of 8.5 mm to 11 mm is secured, while according to the present invention, the interbore portion is over-processed Al-Si. The integrated structure is made of material, so the gap of 6 ~ 6.5mm is sufficient, so the overall length of the engine block can be reduced by more than 7.5mm in case of 4 series cylinders or V8 cylinder, and more than 5mm in case of V6.

This does not mean the length reduction of the engine block alone, but the length reduction of all parts such as the crankshaft, bedplate, camshaft, and cylinder head, which are attached to the engine block. It can be said to be large.

In addition, the aluminum liner manufacturing process of the present invention utilizes the previously developed quality stable mass production process and materials, and can be applied without high load to the high pressure casting process and facilities, which are the main mass production processes of the engine block. This can be called.

In addition, the over-processed Al-Si integrated structure is advantageous over the existing material against the thermal load of the interbore, and the rigidity of the entire engine block and the liner dimension stability required for high pressure casting of the aluminum engine block to cope with high engine power and layout optimization. Etc. can be improved.

On the other hand, the present invention can be applied not only to the conventional aluminum block manufacturing process by high pressure casting, but also to the magnesium engine block manufacturing process to which the surface treatment method is applied to enhance the corrosion resistance with the cooling water.

As described above, according to the manufacturing method of the aluminum liner according to the present invention, in the case of a general four-cylinder engine, four cylindrical liners are used, and in the case of the V6 engine, three liners are provided on each of left and right sides. After integrally manufacturing by low pressure casting with A390 alloy (Al-17% Si-4Cu), which is a general monoblock material, to be connected as a structure, by applying aluminum liner during high pressure casting of aluminum block, the existing engine block interbore structure The overall structure of the engine block can be reduced by the integrated structure of the liner instead of the heterogeneous structure such as the liner / block of the engine. Accordingly, the engine light weight and compactness can be reduced, the heat load of the interbore portion, the rigidity of the entire engine block, and the aluminum It can improve the dimensional stability of liner during high pressure casting of engine block.

Claims (1)

Providing an A390 alloy (Al-17% Si-4Cu) material; In the case of a cylindrical liner applied to an inline four-cylinder engine, four liners are used. In the case of a cylindrical liner applied to a V6 engine, a liner having an integral structure in which three liners are connected to one structure is manufactured. Injecting 17% Si-4Cu) molten metal to produce a liner having an integral structure in which four or three liners are connected to one structure by low pressure casting; Inserting the liner of the unitary structure when the aluminum cylinder block is cast by high pressure casting, integrally forming the liner of the unitary structure with the aluminum cylinder block; Method for producing an aluminum cylinder block comprising an integrated aluminum liner using an over-process A-Si alloy, characterized in that made.

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