JP2022189372A - Engine block, resin block, and method of manufacturing engine block - Google Patents

Abstract

To provide a technology improving thermal efficiency in an engine block equipped with a resin block.SOLUTION: An engine block 10 is equipped with a cylinder liner 120, a resin block 200 consisting of a hardened object of a thermosetting resin, and a water jacket 232 that is provided in an area on an outer peripheral side than the cylinder liner 120. The resin block 200 has a first part 210 provided on an outer peripheral surface side of the cylinder liner 120, and a second part 220 located on the outer side than the first part 210. The first part 210 configures at least a wall surface on the cylinder liner 120 side of the water jacket 232. In an area configuring the wall surface, a heat resistance changing portion is configured, in which heat resistance in a thickness direction when assuming a direction from the cylinder liner 120 to the water jacket 232 as the thickness direction is different in an area on a top dead center side and a bottom dead center side in a stroke direction of a piston.SELECTED DRAWING: Figure 7

Description

The present invention relates to an engine block, a resin block, and a method for manufacturing an engine block.

To reduce the world's carbon dioxide emissions, it is still essential in the automotive sector to reduce the weight of vehicles and improve the efficiency of internal combustion engines. Improving thermal efficiency requires new technology that can significantly reduce energy loss that is wasted without being converted into power during the combustion process. In terms of weight reduction, light metals such as aluminum alloys and magnesium alloys used to be the mainstream for engine parts, but with the realization of resin, significant weight reduction can be expected.

Non-Patent Document 1 discloses an engine provided with a resin surrounding an iron cylinder liner. This document describes that the cooling loss of the engine is reduced when the cylinder liner is surrounded by resin than when the cylinder liner is surrounded by aluminum.

Patent Documents 1 and 2 disclose an engine block provided with a block made of resin surrounding a metal cylinder liner, in which a water jacket is formed on the cylinder liner.

U.S. Patent Application Publication No. 2015/0159581 U.S. Patent Application Publication No. 2015/0159582

Takahiro Mizuno, Ryuki Tsuji, Toshio Fujimura, "Prediction of Fuel Efficiency Improvement of SI Engine Using One-Dimensional Simulation," Proceedings of the 65th Annual Meeting and Lecture Meeting of the Japan Society of Mechanical Engineers Tokai Branch (March 17-18, 2016) No . 163-1

As described above, engines have been proposed that attempt to reduce cooling loss by enclosing the cylinder liner with resin. was needed.

SUMMARY OF THE INVENTION An object of the present invention is to realize a technique for improving thermal efficiency in an engine block having a resin block.

According to the invention,
a cylinder liner having a metal outer peripheral surface;
a resin block composed of a cured product of a thermosetting resin;
a cooling water channel provided in a region on the outer peripheral side of the cylinder liner;
with
The resin block has a first portion provided on the metal outer peripheral surface side of the cylinder liner and a second portion positioned outside the first portion,
The first portion constitutes at least a wall surface of the cooling water passage on the cylinder liner side,
In the region where the first portion constitutes the wall surface, the thermal resistance in the thickness direction when the direction from the cylinder liner to the cooling water passage is taken as the thickness direction is the top dead center side in the stroke direction of the piston. The area and the area on the bottom dead center side constitute different thermal resistance change parts,
We can supply the engine block.
According to the present invention, it is possible to provide a resin block that constitutes the engine block described above.
According to the present invention, there is provided a method for manufacturing an engine block as described above, comprising:
It is possible to provide an engine block manufacturing method in which a resin block is fitted to the outer peripheral surface of a cylinder liner.

According to the present invention, it is possible to realize a technique for improving thermal efficiency in an engine block having a resin block.

It is an exploded view of an engine block and a cylinder head concerning an embodiment. FIG. 2 is a diagram for explaining an example of a method for manufacturing the engine block shown in FIG. 1; FIG. FIG. 2 is a diagram for explaining an example of a method for manufacturing the engine block shown in FIG. 1; FIG. FIG. 2 is a diagram for explaining an example of a method for manufacturing the engine block shown in FIG. 1; FIG. FIG. 2 is a diagram for explaining an example of a method for manufacturing the engine block shown in FIG. 1; FIG. FIG. 3 is a cross-sectional view for explaining an example of details of a cylinder liner and a metal block; FIG. 3 is a longitudinal sectional view for explaining an example of details of a cylinder liner and a metal block; FIG. 4 is a vertical cross-sectional view for explaining an example of a structure having different thermal resistances in the first portion; FIG. 4 is a vertical cross-sectional view for explaining an example of a structure having different thermal resistances in the first portion; FIG. 4 is a vertical cross-sectional view for explaining an example of a structure having different thermal resistances in the first portion; FIG. 4 is a vertical cross-sectional view for explaining an example of a structure having different thermal resistances in the first portion;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, in all the drawings, the same constituent elements are denoted by the same reference numerals, and the description thereof will be omitted as appropriate.

FIG. 1 is a perspective view of an engine block 10 according to an embodiment. Here, the cylinder head attached to the upper side of the engine block 10 is omitted, and only the gasket 28 is shown.

<Overview of engine block 10>
An overview of the engine block 10 will be described with reference to FIG. The engine block 10 has a cylinder liner 120 and a resin block 200 . In FIG. 1 , the resin block 200 is indicated by being blacked out for the sake of convenience. The engine block 10 of a two-cylinder engine will be exemplified below.

Resin block 200 includes first portion 210 and void 230 . The first portion 210 covers the metal outer peripheral surface 122 of the cylinder liner 120 . The air gap 230 is located outside the first portion 210 and defines a water jacket 232 .

According to the configuration described above, damage to resin block 200 due to heat generated from cylinder liner 120 can be reduced.

Specifically, in the configuration described above, first portion 210 of resin block 200 is surrounded by water jacket 232 . A coolant (eg, water) flowing through the water jacket 232 can reduce thermal damage to the first portion 210 of the resin block 200 .

<Engine block 10>
Details of the engine block 10 will be described with reference to FIG.
The engine block 10 has a block member 110 , a cylinder liner 120 , a metal block 140 , projections 130 and a resin block 200 .

Block member 110 is made of metal (eg, cast iron, aluminum alloy, or magnesium alloy). In the example shown in FIG. 1, block member 110 functions as a base for supporting resin block 200 .

Cylinder liner 120 is attached to block member 110 . Cylinder liner 120 may be integral with block member 110 or may be attachable and removable from block member 110 .

Cylinder liner 120 is made of metal (for example, iron or aluminum). Cylinder liner 120 has an outer peripheral surface made of metal (that is, metal outer peripheral surface 122).

Metal block 140 is a part of block member 110 and is provided in a tubular shape so as to cover metal outer peripheral surface 122 of cylinder liner 120 . The cylindrical shape may be a single structure or a structure in which a plurality of structures are connected. A resin block 200 is provided so as to cover the block outer peripheral surface 142 of the metal block 140 . Alternatively, metal block 140 may be omitted and resin block 200 may be provided directly on cylinder liner 120 .

The projection 130 protrudes from the block member 110 toward the cylinder head (or gasket 28). The protrusion 130 has an opening 132 . The fixture 22 can be inserted into the opening 132 . The fixture 22 fixes the cylinder head to the engine block 10 with a gasket 28 interposed therebetween. Fixtures 22 can be, for example, bolts.

<Resin block 200>
Resin block 200 includes first portion 210 , second portion 220 and void 230 . The second portion 220 is positioned outside the gap 230 . A gap 230 is between the first portion 210 and the second portion 220 . The first portion 210 and the second portion 220 are integrated with each other at the lower portion of the resin block 200 .

The first portion 210 of the resin block 200 is attached to the block outer peripheral surface 142 of the metal block 140 via, for example, an adhesive 300 (see FIG. 4). The adhesive is positioned between the first portion 210 of the resin block 200 and the block outer peripheral surface 142 of the metal block 140 to bond the first portion 210 of the resin block 200 and the block outer peripheral surface 142 of the metal block 140 to each other. The adhesive may function as a stress relief layer.

The first portion 210 of the resin block 200 may be integrally joined to the block outer peripheral surface 142 of the metal block 140 without an adhesive. In this case, at the interface between the first portion 210 of the resin block 200 and the block outer peripheral surface 142 of the metal block 140, a direct bond of resin (resin block 200) and metal (metal block 140) is formed.

Resin block 200 has an upper surface 202 . Top surface 202 has grooves that form air gaps 230 that are exposed from block member 110 . Such a structure can particularly reduce thermal damage to the resin block 200 at the upper end of the cylinder liner 120 and its vicinity. Therefore, the structure described above is particularly significant in the case where the temperature of the metal block 140 and the cylinder liner 120 rises particularly at and near their upper ends. Furthermore, in the structure described above, the void 230 can be formed not only before the resin block 200 is attached to the metal block 140 but also after the resin block 200 is attached to the metal block 140 . Therefore, the degree of freedom of the process for forming the void 230 can be increased.

The void 230 may not be exposed from the upper surface 202 of the resin block 200 and may exist inside the resin block 200 . Even in this case, the coolant flowing through the water jacket 232 can reduce thermal damage to the first portion 210 of the resin block 200 .

The second portion 220 has an opening 222 . Resin block 200 is positioned such that protrusion 130 penetrates opening 222 of second portion 220 . The protrusion 130 can function as a guide for attaching the resin block 200 to the block member 110 .

<Materials and Physical Properties of Resin Block 200>
The first portion 210 and the second portion 220 of the resin block 200 contain cured thermosetting resin. In other words, the resin block 200 is made of thermosetting resin. The resin block 200 may further contain an inorganic filler (for example, glass fiber). The resin block 200 may contain, for example, 50% by weight or more of inorganic filler with respect to the total weight of the resin block 200 . The thermosetting resin forming the resin block 200 can be, for example, a phenolic resin.

The thermal conductivity of the thermosetting resin forming the resin block 200 can be low, for example, 1.00 W/m·K or less. A cooling loss of the engine block 10 can be reduced because the thermal conductivity is low.

The density of the thermosetting resin forming the resin block 200 can be small, for example, 2.2 g/cm ³ or less. Since the density is low, the weight of the engine block 10 can be reduced.

The glass transition point of the thermosetting resin forming the resin block 200 can be increased, for example, 160° C. or higher, preferably 200° C. or higher. Since the glass transition point is high, the engine block 10 can be used at high temperatures.

The linear expansion coefficient of the thermosetting resin forming the resin block 200 can be equal to or approximate to the linear expansion coefficient of the metal forming the block outer peripheral surface 142 of the metal block 140 . For example, the machine direction (MD) linear expansion coefficient of the thermosetting resin forming the resin block 200 may be 75% or more and 125% or less of the MD linear expansion coefficient of the metal forming the metal block 140. may be between 75% and 125% of the TD linear expansion coefficient of the metal forming the metal block 140 . By making the linear expansion coefficient of the thermosetting resin forming the resin block 200 and the linear expansion coefficient of the metal forming the metal block 140 equal or similar, when both the metal block 140 and the resin block 200 are heated, stress from the metal block 140 to the resin block 200 can be relieved.

Each of the MD linear expansion coefficient of the thermosetting resin forming the resin block 200 and the MD linear expansion coefficient of the metal forming the metal block 140 can be, for example, 10 ppm or more and 40 ppm or less.

Each of the TD linear expansion coefficient of the thermosetting resin forming the resin block 200 and the TD linear expansion coefficient of the metal forming the metal block 140 can be, for example, 10 ppm or more and 40 ppm or less.

When the metal block 140 is omitted and the cylinder liner 120 is provided with the resin block 200 , the coefficient of linear expansion of the thermosetting resin can be the above value in relation to the cylinder liner 120 .

<Manufacturing Method of Engine Block 10>
2 to 5 are diagrams for explaining an example of a method for manufacturing the engine block 10 shown in FIG. 1. FIG.

An outline of an example of a method for manufacturing the engine block 10 will be described with reference to FIGS. 2, 3 and 5. FIG. First, as shown in FIG. 2, a base block 100 is formed. Base block 100 has cylinder liner 120 and metal block 140 . Cylinder liner 120 has a metallic outer peripheral surface 122 . Metal block 140 surrounds cylinder liner 120 . Next, as shown in FIG. 3, the base block 100 is processed so as to partially remove the metal block 140 so that the thickness of the metal block 140 is reduced. If the metal block 140 before processing has a desired thickness, the processing for removing it is unnecessary. Subsequently, as shown in FIG. 5, the metal block 140 is surrounded by the resin block 200 .

According to the process described above, the manufacturing process for enclosing the metal block 140 and the cylinder liner 120 with the resin block 200 can be realized at low cost. Specifically, in the process described above, the base block 100, including the metal block 140, is removed from existing equipment for forming existing engine blocks (e.g., metal used in casting to form existing engine blocks). mold). That is, even when the metal block 140 is partially removed, there is no need to provide new equipment for forming the base block 100 from which the metal block 140 has been removed. Therefore, the manufacturing process for enclosing the metal block 140 and the cylinder liner 120 with the resin block 200 can be realized at low cost.

Details of an example of a method for manufacturing the engine block 10 will be described with reference to FIGS. 2 to 5. FIG.
First, as shown in FIG. 2, a base block 100 is formed. Base block 100 has block member 110 , cylinder liner 120 and metal block 140 . Each of block member 110, cylinder liner 120 and metal block 140 is made of metal. In particular, metal block 140 is made of, for example, cast iron, an aluminum alloy or a magnesium alloy.

Base block 100 has a gap 150 between cylinder liner 120 and metal block 140 . Air gap 150 defines water jacket 152 . Base block 100 may be formed using existing equipment for forming existing engine blocks (ie, engine blocks with water jackets 152). In one example, the base block 100 can be formed by casting, more specifically die casting. In this example, the mold used for die casting can be an existing mold for forming an engine block.

The base block 100 also has an opening 132 . As described with reference to FIG. 1, fixture 22 (FIG. 1) can be inserted into opening 132 . Base block 100 includes a portion forming projection 130 shown in FIG. This portion forms the projection 130 in the step shown in FIG. 3 (the step of removing the metal block 140).

Next, as shown in FIG. 3, part of the metal block 140 is removed from the base block 100 to reduce the thickness. In the example shown in FIG. 3, the metal block 140 is processed to be thinner around the cylinder liner 120 and removed so that the protrusion 130 is formed and the opening 132 remains.

Next, as shown in FIG. 4, an adhesive 300 is formed on the block outer peripheral surface 142 of the metal block 140 . As shown in FIG. 4, adhesive 300 may also be formed on the outer peripheral surface of protrusion 130 .

Next, as shown in FIG. 5, the resin block 200 is fitted so as to surround the metal block 140 . Resin block 200 is attached so that protrusion 130 penetrates opening 222 of resin block 200 . The first portion 210 of the resin block 200 and the block outer peripheral surface 142 of the metal block 140 are adhered to each other via an adhesive 300 (FIG. 4), and the inner surface of the opening 222 of the resin block 200 and the outer peripheral surface of the projection 130 are adhered. They are adhered together via an agent 300 (FIG. 4).

Adhesive 300 (FIG. 4) may not be formed. When the adhesive 300 is not formed, the first portion 210 of the resin block 200 is integrally joined to the block outer peripheral surface 142 of the metal block 140 without an adhesive (for example, the adhesive 300 (FIG. 4)). may

In the example shown in FIG. 5, the resin block 200 includes a first portion 210, a second portion 220 and voids 230. As shown in FIG. Air gap 230 defines water jacket 232 . The void 230 may be formed before enclosing the metal block 140 with the resin block 200 or after enclosing the metal block 140 with the resin block 200 .

The method of manufacturing the engine block 10 is not limited to the examples shown in FIGS. The engine block 10 may be manufactured as in the following example.

First, the block (block member 110, cylinder liner 120 and projection 130) shown in FIG. 3 may be formed without forming the base block 100 shown in FIG. The block shown in FIG. 3 can be formed by casting, more specifically by die casting. In this example, the die used for die casting has a shape along the block shown in FIG.

Second, engine block 10 may be manufactured by insert molding. In this example, the blocks (block member 110 (metal block 140), cylinder liner 120 and projection 130) shown in FIG. do. According to this example, the resin block 200 can be directly bonded to the metal block 140 without providing the adhesive 300 shown in FIG. As the adhesive 300, for example, a high heat dissipation one-component condensed RTV silicone adhesive sealant (heat transfer coefficient: 0.83 W/mk) can be used.

<Cylinder Liner 120 and Metal Block 140>
6 and 7 are cross-sectional views for explaining an example of details of the cylinder liner 120 and the metal block 140. FIG. FIG. 6 shows a cross section of cylinder liner 120 and metal block 140 . FIG. 7 shows a cross section of cylinder liner 120 and metal block 140 .

Cylinder liner 120 includes an iron layer 120a and an aluminum layer 120b. The iron layer 120 a forms the inner peripheral surface of the cylinder liner 120 . The iron layer 120a contains at least one of iron and ferroalloy. The aluminum layer 120 b is located outside the iron layer 120 a and forms the metal outer peripheral surface 122 . Aluminum layer 120b includes at least one of aluminum and an aluminum alloy.

Metal block 140 is provided to surround aluminum layer 120 b of cylinder liner 120 .

The surface roughness Ra (arithmetic mean roughness) of the block outer peripheral surface 142 of the metal block 140 can be, for example, 0.2 μm or more and 3.0 μm or less.

The block outer peripheral surface 142 of the metal block 140 may not have protrusions with tip angles of less than 90°. Such a protrusion may become a concentration of thermal stress on the metal block 140 and the resin block 200 and may cause cracks in the resin block 200 . Without such protrusions, cracks in the resin block 200 can be reduced.

<Thermal resistance of first portion 210 (1)>
The thermal resistance Rt of the first portion 210 will be described with particular attention to the thickness of the first portion 210 with reference to FIGS. 8 to 11. FIG. 8 to 11 are enlarged views of area A in FIG. 7, respectively, and explain a total of four types of structural examples. In the region where the first portion 210 forms the wall surface 232A of the water jacket 232, the heat resistance Rt in the thickness direction when the direction from the cylinder liner 120 to the water jacket 232 is defined as the thickness direction is A different thermal resistance change portion 170 is formed between the area on the top dead center TDC side and the area on the bottom dead center BDC side. If the composition and density of first portion 210 are constant, thermal resistance Rt is proportional to thickness t of first portion 210 .

In the structural example shown in FIG. 8, the boundary between the water jacket 232 and the first portion 210, that is, the wall surface 232A of the water jacket 232 is a continuously changing region 211 in a cross-sectional view. It has a straight portion 212 changing to .

In the structure of FIG. 8(a), the wall surface 232A is a straight portion 212 that is obliquely straight (slanted) in cross section, and the thickness t of the second portion 220 is thicker on the side of the top dead center TDC than on the side of the bottom dead center BDC. ing. In other words, the thermal resistance change portion 170 has a first region 171 with a large thermal resistance Rt on the upper side (top dead center TDC side) and a first region 171 on the lower side (bottom dead center BDC side). It can be said that this is the second region 172 with a smaller thermal resistance Rt. By increasing the thermal resistance Rt by increasing the thickness t of the first portion 210 on the top dead center TDC side in this way, the timing at which the fuel burns in the combustion chamber (that is, when the piston 190 reaches the top dead center TDC) high thermal efficiency can be achieved by suppressing the escape of heat during combustion to the water jacket 232. Moreover, since the thickness t changes continuously and linearly, local concentration of thermal strain and thermal stress can be avoided. In particular, when combustion timing (that is, heat generation timing) is taken into consideration, the design of the thermal resistance Rt of the first region 171 is as follows for the range from the top dead center TDC to 30%, especially the range up to 20% with respect to the stroke length. is important. Further, by increasing the thickness on the TDC side of the top dead center, the assembling work is facilitated when assembling the resin block 200 to the metal block 140 .

In the structure of FIG. 8(b), the wall surface 232A is obliquely linear in a cross-sectional view, and the thickness t of the second portion 220 is thicker on the bottom dead center BDC side than on the top dead center TDC side. In other words, the thermal resistance change portion 170 has a first region 171 with a large thermal resistance Rt on the lower side (bottom dead center BDC side) and a first region 171 on the upper side (top dead center TDC side). It can be said that this is the second region 172 with a smaller thermal resistance Rt. Since the heat resistance Rt is reduced by reducing the thickness t of the first portion 210 on the top dead center TDC side in this way, the timing at which the fuel burns in the combustion chamber (that is, when the piston 190 is near the top dead center TDC) ), heat can be transferred to the water jacket 232 to facilitate cooling. This is effective in engines where the temperature inside the combustion chamber rises during combustion and knocking is likely to occur. In particular, when combustion timing (that is, heat generation timing) is taken into consideration, the design of the thermal resistance Rt of the second region 172 is as follows for the range from the top dead center TDC to 30%, especially the range up to 20% with respect to the stroke length. is important. Moreover, since the thickness t changes continuously and linearly, local concentration of thermal strain and thermal stress can be avoided.

In the structural example shown in FIG. 9, the boundary between the water jacket 232 and the first portion 210, that is, the wall surface 232A of the water jacket 232 is a continuously changing region 211 in a cross-sectional view. It has a curved portion 213 changing to . As the curved portion 213, various curves can be employed, not limited to the curve that gradually increases or decreases.

In the structure of FIG. 9(a), the wall surface 232A in a sectional view is configured such that the side of the bottom dead center BDC is curved closer to the metal block 140 (that is, the cylinder liner 120) side than the side of the top dead center TDC. In other words, the thickness t of the first portion 210 is thicker on the side of the top dead center TDC than on the side of the bottom dead center BDC, and the change in thickness t is curved. In other words, the thermal resistance change portion 170 has a first region 171 with a large thermal resistance Rt on the upper side (top dead center TDC side) and a first region 171 on the lower side (bottom dead center BDC side). It can be said that this is the second region 172 with a smaller thermal resistance Rt. In this way, by increasing the thickness t of the first portion 210 on the top dead center TDC side and increasing the thermal resistance Rt, the timing at which the fuel burns in the combustion chamber (that is, when the piston 190 is near the top dead center TDC) ), high thermal efficiency can be achieved by suppressing the escape of heat during combustion to the water jacket 232 . Moreover, since the thickness t changes continuously, it is possible to avoid local concentration of thermal strain and thermal stress. In addition, by changing the thickness t in a curved line, it is possible to realize an optimal heat insulation/cooling structure according to the temperature inside the cylinder during and after combustion.

The structure of FIG. 9B is such that the wall surface 232A curves closer to the metal block 140 on the side of the top dead center TDC than on the side of the bottom dead center BDC when viewed in cross section. In other words, the thickness t of the first portion 210 is thinner on the side of the top dead center TDC than on the side of the bottom dead center BDC, and the change in the thickness t is curved. In other words, the thermal resistance change portion 170 has a first region 171 with a large thermal resistance Rt on the lower side (bottom dead center BDC side) and a first region 171 on the upper side (top dead center TDC side). It can be said that this is the second region 172 with a smaller thermal resistance Rt. Since the heat resistance Rt is reduced by reducing the thickness t of the first portion 210 on the top dead center TDC side in this way, the timing at which the fuel burns in the combustion chamber (that is, when the piston 190 is near the top dead center TDC) ), heat can be released to the water jacket 232 to promote cooling, and the occurrence of knocking can be suppressed.
Moreover, since the thickness t changes continuously, it is possible to avoid local concentration of thermal strain and thermal stress. In addition, by changing the thickness t in a curved line, it is possible to realize an optimal heat insulation/cooling structure according to the temperature inside the cylinder during and after combustion.

In the structural example shown in FIG. 10, the boundary between the water jacket 232 and the first portion 210 in cross section, that is, the wall surface 232A of the water jacket 232 is a continuous change region 211 in which the wall surface 232A is continuously changing. One of the cross sections of the wall surface 232A1 on the TDC side and the wall surface 232A2 on the bottom dead center BDC side is vertical and the other is inclined.

In the configuration of FIG. 10A, the wall surface 232A1 on the top dead center TDC side of the change point 175 is provided vertically. A wall surface 232A2 on the bottom dead center BDC side of the change point 175 forms a linear portion 212 (continuous change region 211) inclined so as to approach the metal block 140 side downward, and the thickness t of the second portion 220 reaches the bottom dead center. The top dead center TDC side is thicker than the BDC side. The area on the TDC side of the change point 175 can be called a first area 171 where the thermal resistance Rt is relatively large, and the area on the BDC side of the bottom dead center can be called a second area 172 where the thermal resistance Rt is relatively small. By increasing the thermal resistance Rt by increasing the thickness t of the first portion 210 on the top dead center TDC side in this way, the timing at which the fuel burns in the combustion chamber (that is, when the piston 190 reaches the top dead center TDC) high thermal efficiency can be achieved by suppressing the escape of heat during combustion to the water jacket 232.

In the configuration of FIG. 10(b), the wall surface 232A1 on the side of the top dead center TDC from the point of change 175 forms a linear portion 212 (continuous change region 211) inclined so as to approach the metal block 140 side upward, and the second portion The thickness t of 220 is thicker on the top dead center TDC side than on the bottom dead center BDC side. A wall surface 232A2 on the bottom dead center BDC side of the change point 175 is provided vertically. The area on the BDC side of the change point 175 can be called a first area 171 where the thermal resistance Rt is relatively large, and the area on the top dead center TDC side can be called a second area 172 where the thermal resistance Rt is relatively small. Since the heat resistance Rt is reduced by reducing the thickness t of the first portion 210 on the top dead center TDC side in this way, the timing at which the fuel burns in the combustion chamber (that is, when the piston 190 is near the top dead center TDC) ), heat can be released to the water jacket 232 to promote cooling, and the occurrence of knocking can be suppressed.

In the structural example shown in FIG. 11, the boundary between the water jacket 232 and the first portion 210, that is, the wall surface 232A of the water jacket 232 is discontinuous (that is, stepped) in a cross-sectional view. One of the cross sections of the wall surface 232A1 on the side of the top dead center TDC and the wall surface 232A2 on the side of the bottom dead center BDC is vertical and the other is inclined, and the boundary between them forms a discontinuous portion 214 that is a step. there is In other words, in the configuration of FIG. 10, it can be said that the change point 175 is the discontinuous portion 214 of the step.

In the configuration of FIG. 11A, a wall surface 232A1 on the bottom dead center BDC side of the discontinuous portion 214 is provided vertically. The wall surface 232A2 on the top dead center TDC side of the discontinuous portion 214 is provided in an inclined linear shape so as to become farther from the metal block 140 side, that is, to become thicker toward the upper side. The area on the TDC side of the discontinuous portion 214 can be called a first area 171 where the thermal resistance Rt is relatively large, and the area on the BDC side of the bottom dead center can be called a second area 172 where the thermal resistance Rt is relatively small. 10 can be realized, and the thickness t can be greatly changed at the discontinuous portion 214, so even if the required thermal resistance Rt is greatly different between the top dead center TDC side and the bottom dead center BDC side, it can be handled. is possible.

In the configuration of FIG. 11(b), a wall surface 232A1 on the top dead center TDC side of the discontinuous portion 214 is provided vertically. A wall surface 232A2 closer to the bottom dead center BDC than the discontinuous portion 214 is provided in a linear shape that is inclined so as to approach the metal block 140 side toward the lower side. It can be said that the side of the discontinuous portion 214 on the BDC side of the bottom dead center BDC is a first region 171 where the thermal resistance Rt is relatively large, and the side of the top dead center TDC is the second region 172 where the thermal resistance Rt is relatively small. 10 can be realized, and the thickness t can be greatly changed at the discontinuous portion 214, so even if the required thermal resistance Rt is greatly different between the top dead center TDC side and the bottom dead center BDC side, it can be handled. is possible.

<Thermal resistance of first portion 210 (2)>
In FIGS. 8 to 11, the thermal resistance Rt of the first portion 210 differs depending on the region due to the difference in the thickness of the first portion 210. In addition, the material of the first portion 210 can also give a difference. Specifically, it can be realized by using materials having different thermal conductivities for the first region 171 and the second region 172 . For example, in the first region 171, the hollow ratio per volume in the cured thermosetting resin is increased to reduce the thermal conductivity. That is, the thermal resistance Rt is increased. Conversely, the second region 172 has a smaller hollow ratio than the first region 171 and a higher thermal conductivity. That is, the thermal resistance Rt is reduced. For example, a desired hollow ratio can be achieved by adjusting the content of air bubbles (microballoons) or hollow fillers contained in the cured thermosetting resin.

<Thermal resistance (3) of first portion 210>
Different adhesives 300 (see FIG. 4) are used to attach the resin block 200 to the metal block 140 (or the cylinder liner 120) in order to give the thermal resistance Rt of the first portion 210 different for each region. good too. For example, by using more adhesive on the wall surface corresponding to the first region 171 than to the wall surface corresponding to the second region 172, the thermal resistance Rt in the first region 171 is lower than the thermal resistance Rt in the second region 172. We can make it big.

<Thermal resistance (4) of first portion 210>
In order to give the thermal resistance Rt of the first portion 210 different for each region, unevenness is formed on the inner wall surface of the first portion 210 on the metal block 140 (or cylinder liner 120 ) side to correspond to the second region 172 . The wall surface corresponding to the first region 171 is provided more than the wall surface. The unevenness is formed, for example, in the inner wall surface of the first portion 210 so as to form a circumferential groove. A desired thermal resistance Rt can be achieved by adjusting the width, depth, and number of the grooves for each region. Thereby, the thermal resistance Rt of the first region 171 can be made larger than that of the second region 172 .

Although the embodiments of the present invention have been described above with reference to the drawings, these are examples of the present invention, and various configurations other than those described above can also be adopted. For example, in the above embodiment, an example in which the resin block 200 is applied to a two-cylinder engine (engine block 10) has been described, but it can be applied to a single-cylinder engine or an engine with three or more cylinders regardless of the number of cylinders. can.

10 Engine block 20 Cylinder head 100 Base block 110 Block member 120 Cylinder liner 120a Iron layer 120b Aluminum layer 122 Metal outer peripheral surface 140 Metal block 142 Block outer peripheral surface 150 Gap 152 Water jacket (cooling channel)
170 Thermal resistance changing portion 171 First region 172 Second region 200 Resin block 210 First portion 211 Continuously changing region 212 Straight portion 213 Curved portion 220 Second portion 230 Gap 232 Water jacket (cooling channel)
232A wall surface 300 adhesive

Claims (22)

a cylinder liner having a metal outer peripheral surface;
a resin block composed of a cured product of a thermosetting resin;
a cooling water channel provided in a region on the outer peripheral side of the cylinder liner;
with
The resin block has a first portion provided on the metal outer peripheral surface side of the cylinder liner and a second portion located outside the first portion,
The first portion constitutes at least a wall surface of the cooling water passage on the cylinder liner side,
In the region where the first portion forms the wall surface, the heat resistance in the thickness direction when the direction from the cylinder liner to the cooling water channel is the thickness direction is the top dead center side in the stroke direction of the piston. The area and the area on the bottom dead center side constitute different thermal resistance change parts,
engine block. In the thermal resistance changing portion, the thermal resistance on the top dead center side is greater than or equal to the thermal resistance on the bottom dead center side,
a first region having relatively high thermal resistance;
a second region having a relatively lower thermal resistance than the first region;
The first region is provided in a region closer to the top dead center in the stroke direction of the piston than the second region,
2. An engine block according to claim 1. 3. The engine block according to claim 2, wherein said first region includes at least a region within 20% of the stroke length from the top dead center side. The thermal resistance changing portion has a thermal resistance on the bottom dead center side that is greater than or equal to the thermal resistance on the top dead center side,
a first region having relatively high thermal resistance;
a second region having a relatively smaller thermal resistance than the first region;
The second area is an area closer to the top dead center in the stroke direction of the piston than the first area.
2. An engine block according to claim 1. 5. The engine block according to claim 4, wherein said second region includes at least a region within 20% of the stroke length from the top dead center side. 6. An engine block according to any one of claims 2 to 5, wherein said first region is thicker than said second region. The engine block according to any one of claims 2 to 6, wherein said first region has a larger volume ratio of hollow regions contained in said cured product than said second region. The first region and the second region are composed of cured products of different thermosetting resins,
8. An engine block according to any one of claims 2 to 7, wherein the thermal conductivity of the hardened material of said first region is less than the thermal conductivity of the hardened material of said second region. 9. An engine block as claimed in any one of claims 2 to 8, wherein the thickness of the first portion has a region of continuous variation. 10. The engine block according to claim 9, wherein the region where the thickness of said first portion changes continuously has a region where a boundary of said cooling channel in cross section changes linearly. 11. The engine block according to claim 9 or 10, wherein the region where the thickness of said first portion changes continuously has a region where a cross-sectional boundary of said cooling channel changes in a curved line. 12. An engine block as claimed in any one of claims 2 to 11, wherein the first portion has regions where the thickness varies discontinuously. An adhesive layer is provided on a wall surface of the first portion of the resin block on the cylinder liner side,
The engine block according to any one of claims 2 to 12, wherein more adhesive layers are provided on the wall surface corresponding to the first region than on the wall surface corresponding to the second region. The first portion of the resin block has unevenness on a wall surface on the cylinder liner side,
The engine block according to any one of claims 2 to 13, wherein the wall surface corresponding to the first region has more unevenness than the wall surface corresponding to the second region. 15. An engine block as claimed in any preceding claim, comprising a tubular metal block between the first portion of the resin block and the cylinder liner. 16. An engine block as claimed in any preceding claim, wherein the thermosetting resin forming the first portion of the resin block comprises a phenolic resin. 17. The method according to any one of claims 1 to 16, wherein a cured product of said thermosetting resin forming said first portion of said resin block has a thermal conductivity of 1.00 W/(mK) or less. Engine block as described. The cured product of the thermosetting resin forming the first portion of the resin block has an MD linear expansion coefficient of 75% or more and 125% or less of the MD linear expansion coefficient of the metal forming the metal outer peripheral surface,
The TD linear expansion coefficient of the cured product of the thermosetting resin forming the first portion of the resin block is 75% or more and 125% or less of the TD linear expansion coefficient of the metal forming the metal outer peripheral surface. Item 18. The engine block according to any one of Items 1 to 17. 19. An engine block according to any one of claims 1 to 18, wherein the cured thermosetting resin forming the first portion of the resin block has a density of 2.2 g/cm< ³ > or less. 20. The engine block according to any one of claims 1 to 19, wherein a cured product of said thermosetting resin forming said first portion of said resin block has a glass transition point of 160[deg.]C or higher. A resin block constituting an engine block according to any one of claims 1 to 20. A method for manufacturing an engine block according to any one of claims 1 to 20, comprising:
A method of manufacturing an engine block by fitting a resin block to the outer peripheral surface of a cylinder liner.

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