JP7675982B2 - Engine block, resin block, and method of manufacturing engine block - Google Patents

Description

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

In the automotive sector, reducing the weight of cars and improving the efficiency of internal combustion engines remain essential to reducing global carbon dioxide emissions. Improving thermal efficiency requires new technologies that can significantly reduce the energy lost during the combustion process without being converted into power. From the perspective of weight reduction, the mainstream approach to engine weight reduction has been to use light metals such as aluminum alloys and magnesium alloys for engine parts, but the realization of resins is expected to lead to significant weight reductions.

Non-Patent Document 1 discloses an engine with a resin surrounding an iron cylinder liner. The document states that the cooling loss of an engine is reduced when the cylinder liner is surrounded by resin compared to when the cylinder liner is surrounded by aluminum.

Patent documents 1 and 2 disclose an engine block that includes a resin block that surrounds a metal cylinder liner, with a water jacket formed on the cylinder liner.

US Patent Application Publication No. 2015/0159581 US Patent Application Publication No. 2015/0159582

Takahiro Mizuno, Tatsuki Tsuji, Toshio Fujimura, "Prediction of fuel efficiency improvement of SI engines using one-dimensional simulation," Proceedings of the 65th General Meeting and Lecture Conference of the Tokai Branch of the Japan Society of Mechanical Engineers (March 17-18, 2016), No. 163-1

As mentioned above, engines have been proposed that aim to reduce cooling losses by surrounding the cylinder liner with resin, but in recent years there has been a demand for even greater energy efficiency, and new technology is needed for such engines.

The objective of the present invention is to realize a technology that improves thermal efficiency in engine blocks equipped with resin blocks.

According to the present invention,
A cylinder liner;
a metal block that cylindrically covers an outer circumferential surface of the cylinder liner;
a resin block made of a cured product of a thermosetting resin covering an outer peripheral surface of the metal block;
a cooling water passage provided in an outer circumferential region of the cylinder liner;
Equipped with
the resin block has a first portion covering the metal block 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,
Regarding the surface roughness of the resin block facing the outer peripheral surface of the metal block, the ten-point average roughness Rz defined in JIS B 0601 (1994) is 4.0Z or more and 20Z or less.
Engine blocks can be provided.
According to the present invention, it is possible to provide a resin block that constitutes the above-mentioned engine block.
According to the present invention, there is provided a method for manufacturing an engine block as described above, comprising the steps of:
It is possible to provide a manufacturing method for an engine block in which a resin block is fitted onto the outer peripheral surface of a cylinder liner.

The present invention provides a technology that improves thermal efficiency in an engine block equipped with a resin block.

FIG. 2 is an exploded view of an engine block and a cylinder head according to the embodiment. 2A to 2C are diagrams for explaining an example of a manufacturing method for the engine block shown in FIG. 1 . 2A to 2C are diagrams for explaining an example of a manufacturing method for the engine block shown in FIG. 1 . 2A to 2C are diagrams for explaining an example of a manufacturing method for the engine block shown in FIG. 1 . 2A to 2C are diagrams for explaining an example of a manufacturing method for the engine block shown in FIG. 1 . FIG. 2 is a cross-sectional view for explaining an example of details of a cylinder liner and a metal block. FIG. 2 is a vertical cross-sectional view for explaining an example of details of a cylinder liner and a metal block. 1 is a vertical cross-sectional view for explaining an example of a structure having different thermal resistances in a first portion. FIG. 10 is a vertical cross-sectional view for explaining an example of a structure having different thermal resistances in a first portion. FIG. 1 is a vertical cross-sectional view for explaining an example of a structure having different thermal resistances in a first portion. FIG.

The following describes an embodiment of the present invention with reference to the drawings. Note that in all drawings, similar components are given similar reference numerals and descriptions are omitted where appropriate.

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

<Engine block 10 overview>
An overview of an engine block 10 will be described with reference to Figure 1. The engine block 10 includes a cylinder liner 120 and a resin block 200. For convenience, the resin block 200 is shown painted black in Figure 1. The following describes an example of the engine block 10 for a two-cylinder engine.

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

The above-described configuration can reduce damage to the resin block 200 caused by heat generated from the cylinder liner 120.

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

<Engine block 10>
The engine block 10 will be described in detail with reference to FIG.
The engine block 10 includes a block member 110 , a cylinder liner 120 , a metal block 140 , a projection 130 , and a resin block 200 .

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

The cylinder liner 120 is attached to the block member 110. The cylinder liner 120 may be integral with the block member 110 or may be attachable and detachable to the block member 110.

The cylinder liner 120 is made of a metal (e.g., iron or aluminum). The cylinder liner 120 has an outer peripheral surface made of metal (i.e., the metal outer peripheral surface 122).

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

The protrusion 130 protrudes from the block member 110 toward the cylinder head (or the gasket 28). The protrusion 130 has an opening 132. The fastener 22 can be inserted into the opening 132. The fastener 22 secures the cylinder head to the engine block 10 by sandwiching the gasket 28. The fastener 22 can be, for example, a bolt.

<Resin block 200>
The resin block 200 includes a first portion 210, a second portion 220, and a gap 230. The second portion 220 is located outside the gap 230. The 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 in a 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, for example, via an adhesive layer 300 (see FIG. 4). The adhesive of the adhesive layer 300 is located between the first portion 210 of the resin block 200 and the block outer peripheral surface 142 of the metal block 140, and bonds 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 the use of adhesive. In this case, a direct bond between the resin (resin block 200) and the metal (metal block 140) is formed 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.

The resin block 200 has an upper surface 202. The upper surface 202 has a groove that forms a void 230, and the void 230 is exposed from the block member 110. In such a structure, thermal damage to the resin block 200 at the upper end of the cylinder liner 120 and its vicinity can be particularly reduced. Therefore, the above-mentioned structure is particularly useful when the temperature of the metal block 140 and the cylinder liner 120 particularly rises at their upper ends and their vicinity. Furthermore, in the above-mentioned structure, 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 in the process for forming the void 230 can be increased.

The void 230 may not be exposed from the top surface 202 of the resin block 200, and may be present inside the resin block 200. Even in this case, the refrigerant 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. The resin block 200 is positioned so that the protrusion 130 passes through the opening 222 of the second portion 220. The protrusion 130 can function as a guide for attaching the resin block 200 to the block member 110.

<Materials and Properties of Resin Block 200>
The first portion 210 and the second portion 220 of the resin block 200 contain a cured product of a thermosetting resin. In other words, the resin block 200 is made of a thermosetting resin. The resin block 200 may further contain an inorganic filler (e.g., glass fiber). The resin block 200 may contain, for example, 50% by weight or more of the inorganic filler with respect to the total weight of the resin block 200. The thermosetting resin forming the resin block 200 may 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. This low thermal conductivity can reduce the cooling loss of the engine block 10.

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

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

The linear expansion coefficient of the thermosetting resin forming the resin block 200 can be made equal to or close 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% to 125% of the MD linear expansion coefficient of the metal forming the metal block 140, and the transverse direction (TD) linear expansion coefficient of the thermosetting resin forming the resin block 200 may be 75% to 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 to or close to each other, the stress from the metal block 140 to the resin block 200 when both the metal block 140 and the resin block 200 are heated can be alleviated.

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 each be, for example, 10 ppm or more and 40 ppm or less.

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 each be, for example, 10 ppm or more and 40 ppm or less.

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

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

An example of a manufacturing method for the engine block 10 will be outlined with reference to Figures 2, 3, and 5. First, as shown in Figure 2, a base block 100 is formed. The base block 100 has a cylinder liner 120 and a metal block 140. The cylinder liner 120 has a metal outer circumferential surface 122. The metal block 140 surrounds the cylinder liner 120. Next, as shown in Figure 3, the base block 100 is processed to remove a portion of the metal block 140 so that the thickness of the metal block 140 is reduced. If the metal block 140 before processing has the desired thickness, no processing to remove the portion is necessary. Next, as shown in Figure 5, the metal block 140 is surrounded by a resin block 200.

According to the above-mentioned process, the manufacturing process for surrounding the metal block 140 and the cylinder liner 120 with the resin block 200 can be realized at low cost. Specifically, in the above-mentioned process, the base block 100 including the metal block 140 can be formed using existing equipment for forming an existing engine block (e.g., a mold used for casting to form an existing engine block). In other words, even when a portion of the metal block 140 is removed, it is not necessary to provide new equipment for forming the base block 100 from which the metal block 140 has been removed. Therefore, the manufacturing process for surrounding the metal block 140 and the cylinder liner 120 with the resin block 200 can be realized at low cost.

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

The base block 100 has a gap 150 between the cylinder liner 120 and the metal block 140. The gap 150 defines a water jacket 152. The base block 100 can be formed using existing equipment for forming an existing engine block (i.e., an engine block having a water jacket 152). In one example, the base block 100 can be formed by casting, or more specifically, die casting. In this example, the mold used for die casting can be the mold for forming the existing engine block.

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

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

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

Next, as shown in FIG. 5, the resin block 200 is fitted so as to surround the metal block 140. The resin block 200 is attached so that the protrusion 130 passes through the opening 222 of the 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 bonded to each other via the adhesive layer 300, and the inner surface of the opening 222 of the resin block 200 and the outer peripheral surface of the protrusion 130 are bonded to each other via the adhesive layer 300.

The adhesive layer 300 does not have to be formed. If the adhesive layer 300 is not formed, 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 the use of adhesive.

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

The manufacturing method of the engine block 10 is not limited to the examples shown in Figures 2 to 5. The engine block 10 may be manufactured as shown in the following examples.

First, the block shown in FIG. 3 (block member 110, cylinder liner 120, and protrusion 130) may be formed without forming the base block 100 shown in FIG. 2. The block shown in FIG. 3 can be formed by casting, or more specifically, by die casting. In this example, the mold used for die casting has a shape that corresponds to the block shown in FIG. 3.

Secondly, the engine block 10 may be manufactured by insert molding. In this example, the block (block member 110 (metal block 140), cylinder liner 120 and protrusion 130) shown in FIG. 3 is placed in a mold, and resin for forming the resin block 200 is supplied into the mold. According to this example, the resin block 200 can be directly bonded to the metal block 140 without providing the adhesive layer 300 shown in FIG. 4. For example, a high heat dissipation one-component condensation type RTV silicone adhesive sealant (heat transfer coefficient: 0.83 W/mk) can be used as the adhesive for the adhesive layer 300.

<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. 6 shows a cross section of the cylinder liner 120 and the metal block 140. Fig. 7 shows a cross section of the cylinder liner 120 and the metal block 140.

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

The metal block 140 is arranged to surround the aluminum layer 120b of the cylinder liner 120.

The surface roughness Ra (arithmetic mean roughness) of the block outer 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 be free of protrusions having tip angles of less than 90°. Such protrusions may become areas of thermal stress concentration in the metal block 140 and the resin block 200, and may cause cracks in the resin block 200. If there are no such protrusions, cracks in the resin block 200 can be reduced.

<Joint portion between resin block 200 and metal block 140>
The joining of resin block 200 and metal block 140 will be described with attention to the surface roughness of wall surface 215 of resin block 200 facing outer circumferential surface 141 of metal block 140 (i.e., wall surface 215 at the boundary surface between outer circumferential surface 141 and wall surface 215).

The wall surface 215 of the resin block 200 has a ten-point mean roughness Rz of 4.0Z or more and 20Z or less, as specified in JIS B 0601 (1994). That is, the wall surface 215 has a wall surface unevenness 216 with a ten-point mean roughness Rz in the above range. The uneven structure of the wall surface unevenness 216 can be obtained, for example, by forming grooves in a circumferential manner. By adjusting the width, depth, and number of the grooves for each region, the desired ten-point mean roughness Rz can be achieved, and as a result, the desired thermal resistance Rt can be achieved.

The lower limit of the ten-point mean roughness Rz is preferably 5.0Z or more, and more preferably 6.4Z or more. By setting the lower limit of the ten-point mean roughness Rz within the above range, the area for heat transfer can be secured. In addition, when bonding the metal block 140 and the resin block 200 with the adhesive layer 300, the adhesive can be fixed in the appropriate area, ensuring the bonding.

The upper limit of the ten-point mean roughness Rz is preferably 15.0Z or more, and more preferably 10.0Z or more. By setting the upper limit of the ten-point mean roughness Rz within the above range, the heat transfer from the metal block 140 to the resin block 200 (i.e., thermal resistance Rt) can be set within an appropriate range. That is, an air layer can be created by the uneven structure of the wall surface unevenness portion 216. Since the presence of an air layer increases the thermal resistance Rt, adjusting the size of the air layer can achieve a balance between heat retention and heat dissipation, improving combustion conditions, and ultimately improving thermal efficiency.

With reference to Figures 8 to 10, a configuration for adjusting the thermal resistance Rt by providing an air layer at the boundary between the wall surface 215 of the first portion 210 facing the metal block 140 and the outer peripheral surface 141 of the metal block 140 will be described. Below, as a configuration for providing an air layer, a configuration for providing a wall surface unevenness 216 of the wall surface 215 and a configuration for providing an adhesive layer 300 will be described. Figures 8 to 10 are each an enlarged view of area A in Figure 7.

In the structural example shown in FIG. 8, a first surface roughness region 181 and a second surface roughness region 182 are provided in which the surface roughness (ten-point average roughness Rz) of the wall surface 215 differs between the top dead center TDC side and the bottom dead center BDC side. The surface roughness of the first surface roughness region 181 and the second surface roughness region 182 is set based on the target thermal resistance Rt.

8A, the wall surface 215 has a first surface roughness region 181 with a large surface roughness value on the top dead center TDC side (above the boundary point 145), and a second surface roughness region 182 with a small surface roughness value on the bottom dead center BDC side (below the boundary point 145). As a result, the thermal resistance Rt in the direction from the metal block 140 to the water jacket 232 in the first portion 210 is large in the portion where the first surface roughness region 181 is provided, and is small in the portion where the second surface roughness region 182 is provided.
In this way, by adopting a configuration in which the surface roughness value is larger on the top dead center TDC side than on the bottom dead center BDC side and the thermal resistance Rt is larger, it is possible to suppress the heat generated during combustion from escaping to the water jacket 232 at the timing when the fuel is burned in the combustion chamber (i.e., when the piston 190 is near top dead center TDC), thereby realizing high thermal efficiency. When the combustion timing (i.e., heat generation timing) is taken into consideration, it is preferable to provide the first surface roughness region 181 in a range of up to 30% of the stroke length from top dead center TDC (a range of approximately 45 degrees in crank angle), particularly in a range of up to 20%, to keep the combustion chamber warm.

The structure of Figure 8(b) is the opposite of the structure of Figure 8(a), in that the first surface roughness region 181 has a larger surface roughness value on the bottom dead center BDC side of the wall surface 215 (below boundary point 145), and the surface roughness value is larger than that on the top dead center TDC side (above boundary point 145).
By adopting a configuration in which the surface roughness value is increased on the bottom dead center BDC side from the top dead center TDC side and the thermal resistance Rt is increased in this way, heat can be released to the water jacket 232 at the timing when fuel burns in the combustion chamber (i.e., when the piston 190 is near the top dead center TDC), and cooling can be promoted. This is effective in engines in which the temperature in the combustion chamber rises during combustion and knocking is likely to occur. When considering the combustion timing (i.e., the heat generation timing), it is preferable to provide the first surface roughness region 181 in the range from the top dead center TDC to 30% of the stroke length (a range of approximately 45 degrees in crank angle), particularly in the range up to 20%, to promote cooling of the combustion chamber.

The structural example shown in FIG. 9 is the structural example shown in FIG. 8, further including a change in thickness t of the first portion 210. Specifically, in cross-sectional view, the boundary between the water jacket 232 and the first portion 210, i.e., the wall surface 232A of the water jacket 232, forms a continuous change region 211 where the boundary changes continuously, and in particular has a straight portion 212 where the boundary changes linearly.

9A, the wall surface 232A is a straight portion 212 that is obliquely straight (inclined) in cross section, and the thickness t of the second portion 220 is thicker on the top dead center TDC side than on the bottom dead center BDC side. In other words, the upper side (top dead center TDC side) in the figure is the first region 171 with a large thermal resistance Rt, and the lower side (bottom dead center BDC side) is the second region 172 with a smaller thermal resistance Rt than the first region 171. Furthermore, in the wall surface 215, the region where the first region 171 is provided is the first surface roughness region 181 with a large surface roughness value, and the region where the second region 172 is provided is the second surface roughness region 182 with a small surface roughness value.
In this way, by making the thickness t of the first portion 210 thicker on the top dead center (TDC) side and increasing the surface roughness to increase the thermal resistance Rt, high thermal efficiency can be achieved by suppressing the heat generated during combustion from escaping to the water jacket 232 when the fuel is burned in the combustion chamber (i.e., when the piston 190 is near the top dead center (TDC)). In addition, because the thickness t changes continuously and linearly, it is possible to prevent thermal distortion and thermal stress from concentrating locally.

In the structure of FIG. 9(b), the wall surface 232A is a straight line portion 212 that is diagonally straight in cross section, 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 lower side (bottom dead center BDC side) in the figure is the first region 171 with a large thermal resistance Rt, and the upper side (top dead center TDC side) is the second region 172 with a smaller thermal resistance Rt than the first region 171. Furthermore, in the wall surface 215, the region where the first region 171 is provided is the first surface roughness region 181 with a large surface roughness value, and the region where the second region 172 is provided is the second surface roughness region 182 with a small surface roughness value.

In this way, the thickness t of the first portion 210 on the top dead center TDC side is made thinner, and the surface roughness value on the top dead center TDC side is made smaller than that on the bottom dead center BDC side, making the thermal resistance Rt on the top dead center TDC side smaller than that on the bottom dead center BDC side. This configuration allows heat to escape to the water jacket 232 at the timing when the fuel burns in the combustion chamber (i.e., when the piston 190 is near the top dead center TDC), promoting cooling. This is effective in engines in which the temperature in the combustion chamber rises during combustion and knocking is likely to occur. In particular, when considering the combustion timing (i.e., the heat generation timing), it is important to design the thermal resistance Rt of the second region 172 in the range from the top dead center TDC to 30% of the stroke length, especially in the range up to 20%. In addition, since the thickness t changes continuously and linearly, it is possible to avoid local concentration of thermal distortion and thermal stress.

The continuous change area 211 where the thickness of the first portion 210 changes is not limited to the straight line portion 212, but may be curved. Furthermore, the thickness of the first portion 210 may not change continuously, but may be discontinuous with a step.

In the structural example shown in FIG. 10, in order to provide a difference in the thermal resistance Rt of the first portion 210 for each region, the adhesive in the adhesive layer 300 used to attach the resin block 200 to the metal block 140 (or the cylinder liner 120) is different.

10(a), the adhesive layer 300 provided at the boundary between the outer circumferential surface 141 of the metal block 140 and the wall surface 215 of the cylinder portion 20 is configured to have a first adhesive layer region 301 on the top dead center TDC side (above the boundary point 145) and a second adhesive layer region 302 on the bottom dead center BDC side (below the boundary point 145). A larger amount of adhesive is provided in the first adhesive layer region 301 than in the second adhesive layer region 302. As a result, the first adhesive layer region 301 has a larger air layer than the second adhesive layer region 302, and the thermal resistance Rt is larger.
In this manner, by adopting a configuration in which the thickness of the adhesive layer 300 on the top dead center (TDC) side is made thicker than the bottom dead center (BDC) side and the thermal resistance Rt is increased, it is possible to achieve high thermal efficiency by suppressing the escape of heat during combustion to the water jacket 232 at the timing when the fuel is combusted in the combustion chamber (i.e., when the piston 190 is near top dead center (TDC)).

10(b), the adhesive layer 300 provided at the boundary between the outer peripheral surface 141 of the metal block 140 and the wall surface 215 of the cylinder section 20 is configured to have a first adhesive layer region 301 on the bottom dead center BDC side (below the boundary point 145) where the adhesive is thick, and a second adhesive layer region 302 on the top dead center TDC side (above the boundary point 145) where the adhesive is thin. That is, the first adhesive layer region 301 has a larger air layer due to the thicker adhesive than the second adhesive layer region 302, and the thermal resistance Rt is larger. By adopting a configuration that reduces the thermal resistance Rt on the top dead center TDC side, heat can be released to the water jacket 232 at the timing when the fuel burns in the combustion chamber (i.e., when the piston 190 is near the top dead center TDC), promoting cooling. This is effective in engines in which the temperature in the combustion chamber rises during combustion and knocking is likely to occur.

The configuration of the adhesive layer 300 (first adhesive layer region 301, second adhesive layer region 302) in FIG. 10 may be applied to the configurations in FIG. 8 and FIG. 9.

The above describes an embodiment of the present invention with reference to the drawings, but these are merely 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 was described in which the resin block 200 was applied to a two-cylinder engine (engine block 10), but the resin block 200 can be applied to a single-cylinder engine or an engine with three or more cylinders regardless of the number of cylinders.

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 water passage)
171 First region 172 Second region 181 First surface roughness region 182 Second surface roughness region 200 Resin block 210 First portion 211 Continuously changing region 212 Straight portion 213 Curved portion 214 Boundary 215 Wall surface 216 Wall surface uneven portion 220 Second portion 230 Void 232 Water jacket (cooling water channel)
232A wall surface 300 adhesive layer 301 first adhesive layer area 302 second adhesive layer area

Claims (12)

A cylinder liner;
a metal block that cylindrically covers an outer circumferential surface of the cylinder liner;
a resin block made of a cured product of a thermosetting resin covering an outer peripheral surface of the metal block;
a cooling water passage provided in an outer circumferential region of the cylinder liner;
Equipped with
the resin block has a first portion covering the metal block 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,
the surface roughness of the resin block facing the outer peripheral surface of the metal block is 4.0Z or more and 20Z or less in terms of ten-point average roughness Rz defined in JIS B 0601 (1994);
the wall surface has a first surface roughness region and a second surface roughness region having different surface roughnesses;
An engine block, wherein the first surface roughness region has a surface roughness greater than that of the second surface roughness region, and is located closer to top dead center in a piston stroke direction than the second surface roughness region. In a region where the first portion constitutes the wall surface, a first region and a second region having different thicknesses are provided when a direction from the cylinder liner to the cooling water passage is defined as a thickness direction, and the thickness of the first region is thicker than the thickness of the second region,
The engine block of claim 1 , wherein the first region is provided in the first surface roughness region. The engine block according to claim 1 or 2, further comprising an adhesive layer provided between the first portion of the resin block and the metal block. The adhesive layer has a first adhesive layer region and a second adhesive layer region having different adhesive thicknesses,
4. The engine block of claim 3, wherein the adhesive in the first adhesive layer region is provided thicker than the adhesive in the second adhesive layer region and is provided in the first surface roughness region. The engine block according to any one of claims 1 to 4, wherein the thermal conductivity of the cured product of the thermosetting resin forming the first portion of the resin block is 1.00 W/(m·K) or less. the MD 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 MD linear expansion coefficient of the metal forming the metal block,
6. The engine block according to claim 1, wherein a 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 a TD linear expansion coefficient of a metal forming the metal block. 7. The engine block according to claim 1, wherein the hardened thermosetting resin forming the first portion of the resin block has a density of 2.2 g/ ^cm3 or less. The engine block according to any one of claims 1 to 7, wherein the glass transition point (Tg) of the cured product of the thermosetting resin forming the first portion of the resin block is 160°C or higher. The engine block according to any one of claims 1 to 8, wherein the cured thermosetting resin forming the first portion of the resin block is made of a phenolic resin. A cylinder liner;
a metal block that cylindrically covers an outer circumferential surface of the cylinder liner;
a resin block made of a cured product of a thermosetting resin covering an outer peripheral surface of the metal block;
a cooling water passage provided in an outer circumferential region of the cylinder liner;
Equipped with
the resin block has a first portion covering the metal block 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,
the surface roughness of the resin block facing the outer peripheral surface of the metal block is 4.0Z or more and 20Z or less in terms of ten-point average roughness Rz defined in JIS B 0601 (1994);
an adhesive layer provided between the first portion of the resin block and the metal block ;
The adhesive layer has a first adhesive layer region and a second adhesive layer region having different adhesive thicknesses,
The adhesive in the first adhesive layer region is provided thicker than the adhesive in the second adhesive layer region,
The first adhesive layer region is provided closer to the top dead center than the second adhesive layer region.
Engine block. A resin block constituting an engine block according to any one of claims 1 to 10. A method for manufacturing an engine block according to any one of claims 1 to 10, comprising the steps of:
A manufacturing method for an engine block in which a resin block is fitted onto the outer peripheral surface of a cylinder liner.

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