Patent Description:
An internal combustion engine of an automobile has an engine block. The engine block includes a cylinder liner.

An example of an engine is disclosed in Non-Patent Document <NUM>. The engine includes a cylinder liner and a resin that surrounds the cylinder liner. The cylinder liner is made of iron. Non-Patent Document <NUM> discloses that a cooling loss of the engine is reduced in a case in which the resin surrounds the cylinder liner as compared with a case in which aluminum surrounds the cylinder liner.

Patent Documents <NUM> and <NUM> disclose examples of an engine block. The engine block includes a cylinder liner and a block that surrounds the cylinder liner. The cylinder liner is made of a metal. The block is made of a resin. A water jacket is formed on the cylinder liner. Patent Document <NUM> discloses an engine block comprising a cylinder liner having a metal outer circumferential surface, and a resin block, wherein the resin block includes a first portion that covers the metal outer circumferential surface of the cylinder liner, and a gap that is positioned outside the first portion and defines a water jacket. Patent Document <NUM> discloses an engine block with a liner made of metal, a resin block with fiber glass non organic filler, and a gap/water jacket. Patent Document <NUM> discloses an engine block with a liner made of metal, and a resin block with fiber glass non organic filler.

As disclosed in Non-Patent Document <NUM>, the cylinder liner may be surrounded with the resin in order to reduce the cooling loss. However, the present inventors have found that in a case in which the cylinder liner is surrounded with the resin, the resin can be damaged by heat generated from the cylinder liner.

An example of an object of the first aspect of the present invention is to reduce damage of the resin due to the heat generated from the cylinder liner. Another object of the first aspect of the present invention will be clarified from the description in the present specification.

As disclosed in Non-Patent Document <NUM>, the cylinder liner may be surrounded with the resin in order to reduce the cooling loss. The present inventors have studied to realize a manufacturing process for surrounding the cylinder liner with the resin at a low cost.

An example of an object of the second aspect of the present invention is to realize the manufacturing process for surrounding the cylinder liner with the resin at a low cost. Another object of the second aspect of the present invention will be clarified from the description in the present specification.

An example of the first aspect of the present invention is an engine block including a block member made of a metal, a cylinder liner attached to the block member, the cylinder liner having a metal outer circumferential surface; and.

Another example of the first aspect of the present invention is a resin block including a first portion that covers a metal outer circumferential surface of a cylinder liner of an engine block, and a gap that is positioned outside the first portion and defines a water jacket.

Still another example of the first aspect of the present invention is a method of manufacturing an engine block, the method including.

According to the first aspect of the present invention, the damage of the resin due to the heat generated from the cylinder liner can be reduced.

According to the second aspect of the present invention, the manufacturing process for surrounding the cylinder liner with the resin can be realized at a low cost.

The objects described above and other objects, features and advantages will be further clarified by the preferred embodiment described below and the accompanying drawings below.

In all drawings, similar components are designated by the same reference numerals, and description thereof will not be repeated.

<FIG> is an exploded view of an engine block <NUM> and a cylinder head <NUM> according to an embodiment.

With reference to <FIG>, an outline of the engine block <NUM> will be described. The engine block <NUM> includes a cylinder liner <NUM> and a resin block <NUM>. The cylinder liner <NUM> has a metal outer circumferential surface <NUM>. The resin block <NUM> includes a first portion <NUM> and a gap <NUM>. The first portion <NUM> covers the metal outer circumferential surface <NUM> of the cylinder liner <NUM>. The gap <NUM> is positioned outside the first portion <NUM> and defines a water jacket <NUM>.

According to the configuration described above, the damage of the resin block <NUM> due to heat generated from the cylinder liner <NUM> can be reduced. Specifically, in the configuration described above, the first portion <NUM> of the resin block <NUM> is surrounded with the water jacket <NUM>. Therefore, the thermal damage of the first portion <NUM> of the resin block <NUM> can be reduced by a refrigerant (for example, water) which flows through the water jacket <NUM>.

With reference to <FIG>, the details of the engine block <NUM> will be described.

The engine block <NUM> includes a block member <NUM>, the cylinder liner <NUM>, a protrusion <NUM>, and the resin block <NUM>.

The block member <NUM> is made of a metal (for example, cast iron, an aluminum alloy or a magnesium alloy). In the example shown in <FIG>, the block member <NUM> functions as a base that supports the resin block <NUM>.

The cylinder liner <NUM> is attached to the block member <NUM>. The cylinder liner <NUM> may be integrated with the block member <NUM>, or may be attachable to and detachable from the block member <NUM>.

The cylinder liner <NUM> is made of a metal (for example, iron or aluminum). The cylinder liner <NUM> has an outer circumferential surface made of a metal (that is, the metal outer circumferential surface <NUM>).

The protrusion <NUM> protrudes from the block member <NUM> toward the cylinder head <NUM> (that is, above the engine block <NUM>). The protrusion <NUM> has an opening <NUM>. A fixing tool <NUM> can be inserted into the opening <NUM>. The fixing tool <NUM> fixes the cylinder head <NUM> to the engine block <NUM>. As the fixing tool <NUM>, for example, a bolt can be used.

The resin block <NUM> includes the first portion <NUM>, a second portion <NUM>, and the gap <NUM>. The second portion <NUM> is positioned outside the gap <NUM>. The gap <NUM> is positioned between the first portion <NUM> and the second portion <NUM>. The first portion <NUM> and the second portion <NUM> are integrated with each other.

The first portion <NUM> of the resin block <NUM> may be attached to the metal outer circumferential surface <NUM> of the cylinder liner <NUM> through an adhesive (for example, an adhesive <NUM> which will be described below with reference to <FIG>). The adhesive is positioned between the first portion <NUM> of the resin block <NUM> and the metal outer circumferential surface <NUM> of the cylinder liner <NUM>, and bonds the first portion <NUM> of the resin block <NUM> and the metal outer circumferential surface <NUM> of the cylinder liner <NUM> to each other. The adhesive may function as a stress relaxing layer.

The first portion <NUM> of the resin block <NUM> may be integrally bonded to the metal outer circumferential surface <NUM> of the cylinder liner <NUM> without the adhesive (for example, the adhesive <NUM> which will be described below with reference to <FIG>). In this case, a direct bond between the resin (resin block <NUM>) and the metal (cylinder liner <NUM>) is formed at an interface between the first portion <NUM> of the resin block <NUM> and the metal outer circumferential surface <NUM> of the cylinder liner <NUM>.

The resin block <NUM> has an upper surface <NUM>. The upper surface <NUM> has a groove that forms the gap <NUM> and is exposed from the block member <NUM>. In such a structure, the thermal damage of the resin block <NUM> at an upper end of the cylinder liner <NUM> and the vicinity thereof can be particularly reduced. Therefore, the structure described above is particularly meaningful in a case in which the temperature of the cylinder liner <NUM> rises particularly at the upper end of the cylinder liner <NUM> and the vicinity thereof. Further, in the structure described above, the gap <NUM> can be formed after attaching the resin block <NUM> to the cylinder liner <NUM> as well as before attaching the resin block <NUM> to the cylinder liner <NUM>. As a result, a degree of freedom of a process for forming the gap <NUM> can be increased.

The gap <NUM> may not be exposed from the upper surface <NUM> of the resin block <NUM>, or may be present inside the resin block <NUM>. Even in this case, the thermal damage of the first portion <NUM> of the resin block <NUM> can be reduced by the refrigerant which flows through the water jacket <NUM>.

The second portion <NUM> has an opening <NUM>. The resin block <NUM> is positioned such that the protrusion <NUM> penetrates the opening <NUM> of the second portion <NUM>. The protrusion <NUM> can function as a guide that attaches the resin block <NUM> to the block member <NUM>.

The first portion <NUM> and the second portion <NUM> of the resin block <NUM> contain a cured product of a thermosetting resin. Stated another way, the resin block <NUM> is made of the thermosetting resin. The resin block <NUM> may further contain an inorganic filler (for example, a glass fiber). The resin block <NUM> may contain, for example, <NUM>% by weight or more of the inorganic filler with respect to a total weight of the resin block <NUM>.

As the thermosetting resin that forms the resin block <NUM>, for example, a phenol resin can be used.

A thermal conductivity of the thermosetting resin that forms the resin block <NUM> can be made low, for example, can be <NUM> W/m·K or less. The thermal conductivity is low, so that a cooling loss of the engine block <NUM> can be reduced.

A density of the thermosetting resin that forms the resin block <NUM> can be made small, for example, can be <NUM>/cm<NUM> or less. The density is small, so that a weight of the engine block <NUM> can be reduced.

A glass transition point of the thermosetting resin that forms the resin block <NUM> can be made high, for example, can be <NUM> or higher, and preferably <NUM> or higher. The glass transition point is high, so that the engine block <NUM> can be used at a high temperature.

A linear expansion coefficient of the thermosetting resin that forms the resin block <NUM> can be made equal to or approximate to a linear expansion coefficient of the metal that forms the metal outer circumferential surface <NUM> of the cylinder liner <NUM>. For example, a machine direction (MD) linear expansion coefficient of the thermosetting resin that forms the resin block <NUM> may be <NUM>% or more and <NUM>% or less of a MD linear expansion coefficient of the metal that forms the cylinder liner <NUM>, and a transverse direction (TD) linear expansion coefficient of the thermosetting resin that forms the resin block <NUM> may be <NUM>% or more and <NUM>% or less of a TD linear expansion coefficient of the metal that forms the cylinder liner <NUM>. The linear expansion coefficient of the thermosetting resin that forms the resin block <NUM> and the linear expansion coefficient of the metal that forms the cylinder liner <NUM> are made equal to or approximate to each other, so that the stress from the cylinder liner <NUM> to the resin block <NUM> in a case in which both the cylinder liner <NUM> and the resin block <NUM> are heated can be relaxed.

Each of the MD linear expansion coefficient of the thermosetting resin that forms the resin block <NUM> and the MD linear expansion coefficient of the metal that forms the cylinder liner <NUM> can be, for example, <NUM> ppm or more and <NUM> ppm or less.

Each of the TD linear expansion coefficient of the thermosetting resin that forms the resin block <NUM> and the TD linear expansion coefficient of the metal that forms the cylinder liner <NUM> can be, for example, <NUM> ppm or more and <NUM> ppm or less.

<FIG> are views for describing examples of a method of manufacturing the engine block <NUM> shown in <FIG>.

With reference to <FIG>, <FIG> and <FIG>, an outline of the example of the method of manufacturing the engine block <NUM> will be described. First, a base block <NUM> is formed, as shown in <FIG>. The base block <NUM> has the cylinder liner <NUM> and a metal block <NUM>. The cylinder liner <NUM> has the metal outer circumferential surface <NUM>. The metal block <NUM> surrounds the cylinder liner <NUM>. Next, the metal block <NUM> is removed from the base block <NUM>, as shown in <FIG>. Then, the cylinder liner <NUM> is surrounded with the resin block <NUM>, as shown in <FIG>.

According to the process described above, a manufacturing process for surrounding the cylinder liner <NUM> with the resin block <NUM> can be realized at a low cost. Specifically, in the process described above, the base block <NUM> including the metal block <NUM> can be formed by using existing equipment for forming an existing engine block (for example, a mold used for casting to form an existing engine block). That is, it is not necessary to provide new equipment for forming the base block <NUM> from which the metal block <NUM> is removed. Therefore, the manufacturing process for surrounding the cylinder liner <NUM> with the resin block <NUM> can be realized at a low cost.

With reference to <FIG>, the details of the example of the method of manufacturing the engine block <NUM> will be described.

First, the base block <NUM> is formed, as shown in <FIG>. The base block <NUM> has the block member <NUM>, the cylinder liner <NUM>, and the metal block <NUM>. The block member <NUM>, the cylinder liner <NUM>, and the metal block <NUM> are each made of a metal. Particularly, the metal block <NUM> is made of, for example, cast iron, an aluminum alloy or a magnesium alloy.

The base block <NUM> has a gap <NUM> between the cylinder liner <NUM> and the metal block <NUM>. The gap <NUM> defines a water jacket <NUM>. The base block <NUM> can be formed by using existing equipment for forming an existing engine block (that is, the engine block having the water jacket <NUM>). In the example, the base block <NUM> can be formed by casting, more specifically, die casting. In this example, as the mold used for die casting, the mold for forming the existing engine block can be used.

The base block <NUM> further has the opening <NUM>. As described with reference to <FIG>, the fixing tool <NUM> (<FIG>) can be inserted into the opening <NUM>. The base block <NUM> includes a portion that forms the protrusion <NUM> shown in <FIG>. This portion forms the protrusion <NUM> in a step shown in <FIG> (step of removing the metal block <NUM>).

Next, the metal block <NUM> is removed from the base block <NUM>, as shown in <FIG>. In the example shown in <FIG>, the metal block <NUM> is removed such that the protrusion <NUM> is formed and the opening <NUM> remains.

Next, the adhesive <NUM> is formed on the metal outer circumferential surface <NUM> of the cylinder liner <NUM>, as shown in <FIG>. The adhesive <NUM> may also be formed on an outer circumferential surface of the protrusion <NUM>, as shown in <FIG>.

Then, the cylinder liner <NUM> is surrounded with the resin block <NUM>, as shown in <FIG>. The resin block <NUM> is attached such that the protrusion <NUM> penetrates the opening <NUM> of the resin block <NUM>. The first portion <NUM> of the resin block <NUM> and the metal outer circumferential surface <NUM> of the cylinder liner <NUM> are bonded to each other through the adhesive <NUM> (<FIG>), and an inner surface of the opening <NUM> of the resin block <NUM> and the outer circumferential surface of the protrusion <NUM> are bonded to each other through the adhesive <NUM> (<FIG>).

The adhesive <NUM> (<FIG>) may not be formed. In a case in which the adhesive <NUM> is not formed, the first portion <NUM> of the resin block <NUM> may be integrally bonded to the metal outer circumferential surface <NUM> of the cylinder liner <NUM> without the adhesive (for example, the adhesive <NUM> (<FIG>)).

In the example shown in <FIG>, the resin block <NUM> includes the first portion <NUM>, the second portion <NUM>, and the gap <NUM>. The gap <NUM> defines the water jacket <NUM>. The gap <NUM> may be formed before surrounding the cylinder liner <NUM> with the resin block <NUM>, or may be formed after surrounding the cylinder liner <NUM> with the resin block <NUM>.

The method of manufacturing the engine block <NUM> is not limited to the examples shown in <FIG>. The engine block <NUM> may be manufactured as in the following examples.

First, the blocks (block member <NUM>, cylinder liner <NUM>, and protrusion <NUM>) shown in <FIG> may be formed without forming the base block <NUM> shown in <FIG>. The blocks shown in <FIG> can be formed by casting, more specifically, die casting. In this example, the mold used for die casting has a shape along the blocks shown in <FIG>.

Second, the engine block <NUM> may be manufactured by insert molding. In this example, the blocks (block member <NUM>, cylinder liner <NUM>, and protrusion <NUM>) shown in <FIG> are disposed in the mold, and the resin that forms the resin block <NUM> is supplied into the mold. According to this example, the resin block <NUM> can be directly bonded to the cylinder liner <NUM> without the adhesive <NUM> shown in <FIG>.

<FIG> is a cross-sectional view for describing a detailed example of the cylinder liner <NUM>. <FIG> shows a cross section perpendicular to a height of the cylinder liner <NUM> (vertical direction in <FIG>).

The cylinder liner <NUM> includes an iron layer 120a and an aluminum layer 120b. The iron layer 120a forms an inner circumferential surface of the cylinder liner <NUM>. The iron layer 120a contains at least one of iron and ferroalloy. The aluminum layer 120b is positioned outside the iron layer 120a and forms the metal outer circumferential surface <NUM>. The aluminum layer 120b contains at least one of aluminum and an aluminum alloy.

A surface roughness Ra (arithmetic average roughness) of the metal outer circumferential surface <NUM> of the cylinder liner <NUM> can be, for example, <NUM> or more and <NUM> or less.

The metal outer circumferential surface <NUM> of the cylinder liner <NUM> may not have a protruding portion having a point angle of less than <NUM>°. Such a protruding portion can be a concentrated portion of the thermal stress of the cylinder liner <NUM> and the resin block <NUM>, and can cause cracks in the resin block <NUM>. In a case in which such a protruding portion is not provided, cracks in the resin block <NUM> can be reduced.

Claim 1:
An engine block (<NUM>) comprising:
a block member (<NUM>) made of a metal;
a cylinder liner (<NUM>) attached to the block member (<NUM>), the cylinder liner (<NUM>) having a metal outer circumferential surface (<NUM>); and
a protrusion (<NUM>) protruding from the block member (<NUM>) toward a cylinder head (<NUM>), the protrusion (<NUM>) having a first opening (<NUM>) into which a fixing tool (<NUM>) to fix the cylinder head (<NUM>) to the engine block (<NUM>) is insertable; and
a resin block (<NUM>), the resin block (<NUM>) including a first portion (<NUM>) that covers the metal outer circumferential surface (<NUM>) of the cylinder liner (<NUM>), a gap (<NUM>) that is positioned outside the first portion (<NUM>) and defines a water jacket (<NUM>), and a second portion (<NUM>) that is positioned outside the gap (<NUM>) and has a second opening (<NUM>),
wherein the resin block (<NUM>) is positioned such that the protrusion (<NUM>) penetrates the second opening (<NUM>) of the second portion (<NUM>).