Engine block, resin block, and method of manufacturing engine block

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 metal block 140 that cylindrically covers an outer peripheral surface of the cylinder liner 120, a resin block 200 consisting of a hardened object of a thermosetting resin covering an outer peripheral surface 141 of the metal block 140, and a water jacket 232 provided in an outer peripheral area of the cylinder liner 120. The resin block 200 has a first part 210 covering the metal block 140, 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 152. Concerning the surface roughness of a surface (wall surface 215) opposing to the outer peripheral surface 141 of the metal block 140 of the resin block 200, ten-point average roughness Rz regulated by JIS B 0601(1994) is at least 4.0Z to at most 20Z.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to an engine block, a resin block, and a method for manufacturing an engine block. [Background technology]

[0002] In the automotive sector, reducing the weight of cars and improving the efficiency of internal combustion engines remain essential to reduce 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.

[0003] Non-Patent Document 1 discloses an engine with a resin surrounding an iron cylinder liner, and describes 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.

[0004] Patent Documents 1 and 2 disclose an engine block that includes a block made of resin surrounding a metal cylinder liner, with a water jacket formed on the cylinder liner. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] US Patent Application Publication No. 2015 / 0159581 [Patent Document 2] US Patent Application Publication No. 2015 / 0159582 [Non-patent literature]

[0006] [Non-Patent Document 1] 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 Summary of the Invention [Problem to be solved by the invention]

[0007] As mentioned above, engines have been proposed in which the cylinder liner is surrounded by resin to reduce cooling loss. However, in recent years there has been a demand for even greater energy utilization efficiency, and new technology was needed for such engines.

[0008] An object of the present invention is to realize a technique for improving the thermal efficiency of an engine block having a resin block. [Means for solving the problem]

[0009] 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, 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 the ten-point average roughness Rz defined in JIS B 0601 (1994). 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. Effect of the Invention

[0010] According to the present invention, it is possible to realize a technique for improving the thermal efficiency of an engine block having a resin block. [Brief description of the drawings]

[0011] [Figure 1] FIG. 2 is an exploded view of an engine block and a cylinder head according to the embodiment. [Diagram 2] 2A to 2C are diagrams for explaining an example of a manufacturing method for the engine block shown in FIG. 1. [Diagram 3] 2A to 2C are diagrams for explaining an example of a manufacturing method for the engine block shown in FIG. 1. [Figure 4] 2A to 2C are diagrams for explaining an example of a manufacturing method for the engine block shown in FIG. 1. [Diagram 5] 2A to 2C are diagrams for explaining an example of a manufacturing method for the engine block shown in FIG. 1. [Figure 6] FIG. 2 is a cross-sectional view for explaining an example of details of a cylinder liner and a metal block. [Figure 7] FIG. 2 is a vertical cross-sectional view for explaining an example of details of a cylinder liner and a metal block. [Figure 8] FIG. 2 is a vertical cross-sectional view for explaining an example of a structure having different thermal resistances in a first portion. [Figure 9] FIG. 2 is a vertical cross-sectional view for explaining an example of a structure having different thermal resistances in a first portion. [Figure 10] FIG. 2 is a vertical cross-sectional view for explaining an example of a structure having different thermal resistances in a first portion. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same components are denoted by the same reference numerals, and the description thereof will be omitted as appropriate.

[0013] 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 a gasket 28 is shown.

[0014] <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.

[0015] The resin block 200 includes a first portion 210 and a gap 230. The first portion 210 covers the metal outer peripheral surface 122 of the cylinder liner 120. The gap 230 is located outside the first portion 210 and defines a water jacket 232.

[0016] According to the above-mentioned configuration, damage to the resin block 200 caused by the heat generated from the cylinder liner 120 can be reduced.

[0017] 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 in the water jacket 232 can reduce thermal damage to the first portion 210 of the resin block 200.

[0018] <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 .

[0019] The block member 110 is made of a metal (for example, cast iron, an aluminum alloy, or a magnesium alloy). In the example shown in FIG.

[0020] 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.

[0021] The cylinder liner 120 is made of a metal (for example, iron or aluminum) and has an outer circumferential surface made of metal (i.e., a metal outer circumferential surface 122).

[0022] The metal block 140 is a 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.

[0023] The projection 130 projects from the block member 110 toward the cylinder head (or the gasket 28). The projection 130 has an opening 132. The fastener 22 can be inserted into the opening 132. The fastener 22 fixes the cylinder head to the engine block 10 by sandwiching the gasket 28. The fastener 22 can be, for example, a bolt.

[0024] <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.

[0025] 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 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 relaxation layer.

[0026] 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 using an 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.

[0027] 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 meaningful when the temperatures of the metal block 140 and the cylinder liner 120 particularly rise 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.

[0028] The void 230 may not be exposed from the upper surface 202 of the resin block 200, and may be present inside the resin block 200. Even in this case, the coolant flowing in the water jacket 232 can reduce thermal damage to the first portion 210 of the resin block 200.

[0029] The second portion 220 has an opening 222. The resin block 200 is positioned such 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.

[0030] <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.

[0031] The thermal conductivity of the thermosetting resin forming the resin block 200 can be made low, for example, 1.00 W / m K or less. The low thermal conductivity can reduce the cooling loss of the engine block 10.

[0032] The density of the thermosetting resin forming the resin block 200 can be low, for example, 2.2 g / cm 3 The low density allows the engine block 10 to be made lighter.

[0033] 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.

[0034] 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% or more and 125% or less 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% or more and 125% or less 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, it is possible to reduce 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.

[0035] 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, not less than 10 ppm and not more than 40 ppm.

[0036] 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, not less than 10 ppm and not more than 40 ppm.

[0037] When 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.

[0038] <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.

[0039] An example of a manufacturing method for the engine block 10 will be outlined with reference to Figs. 2, 3 and 5. First, as shown in Fig. 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 peripheral surface 122. The metal block 140 surrounds the cylinder liner 120. Next, as shown in Fig. 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 a desired thickness, the removal process is not necessary. Next, as shown in Fig. 5, the metal block 140 is surrounded by a resin block 200.

[0040] 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 (for example, a mold used in casting for forming an existing engine block). In other words, even when a part of the metal block 140 is processed by removing, it is not necessary to install 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.

[0041] 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.

[0042] 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 existing engine blocks (i.e., engine blocks having water jackets 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.

[0043] 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 for forming 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).

[0044] Next, as shown in Fig. 3, a 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 so as to reduce the thickness around the cylinder liner 120, and is removed so as to form the protrusion 130 and leave the opening 132.

[0045] 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 .

[0046] 5, the resin block 200 is fitted into the metal block 140 so as to surround it. The resin block 200 is attached so that the protrusion 130 penetrates 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 an 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.

[0047] It is not necessary to form the adhesive layer 300. In the case where 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 intervention of an adhesive.

[0048] 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.

[0049] The method for manufacturing the engine block 10 is not limited to the examples shown in Figures 2 to 5. The engine block 10 may be manufactured as in the following example.

[0050] First, the block shown in FIG. 3 (the block member 110, the cylinder liner 120, and the 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, more specifically, by die casting. In this example, the mold used for die casting has a shape corresponding to the block shown in FIG. 3.

[0051] 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 a 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. As the adhesive for the adhesive layer 300, for example, a high heat dissipation one-component condensation type RTV silicone adhesive sealant (heat transfer coefficient: 0.83 W / mk) can be used.

[0052] <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.

[0053] 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.

[0054] The metal block 140 is provided so as to surround the periphery of the aluminum layer 120 b of the cylinder liner 120 .

[0055] The surface roughness Ra (arithmetic mean roughness) of the block outer peripheral surface 142 of the metal block 140 can be set to, for example, not less than 0.2 μm and not more than 3.0 μm.

[0056] The block outer peripheral surface 142 of the metal block 140 may not have any protrusions having a tip angle of less than 90°. Such protrusions may become a concentration point of thermal stress 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.

[0057] <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 (that is, wall surface 215 at the boundary surface between outer circumferential surface 141 and wall surface 215).

[0058] 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 defined in JIS B 0601 (1994). That is, the wall surface 215 has a wall surface unevenness 216 having 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.

[0059] 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 the metal block 140 and the resin block 200 are bonded with the adhesive layer 300, the adhesive can be fixed in an appropriate area, and the bonding can be ensured.

[0060] 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 balance heat retention and heat dissipation, improving combustion conditions, and ultimately improving thermal efficiency.

[0061] 8 to 10, a configuration for adjusting thermal resistance Rt by providing an air layer at the boundary between wall surface 215 of first portion 210 on the metal block 140 side and outer circumferential surface 141 of metal block 140 will be described. As a configuration for providing an air layer, a configuration for providing wall surface unevenness 216 of wall surface 215 and a configuration for providing adhesive layer 300 will be described below. FIGS. 8 to 10 are each an enlarged view of region A in FIG. 7.

[0062] 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.

[0063] 8(a), 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 increased on the top dead center TDC side from the bottom dead center BDC side and the thermal resistance Rt is increased, high thermal efficiency can be achieved by suppressing 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). 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 up to 20%, to keep the combustion chamber warm.

[0064] The structure in Figure 8(b) is the opposite of the structure in 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 is larger than the surface roughness value on the top dead center TDC side (above boundary point 145). In this way, 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, 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 the combustion timing (i.e., the heat generation timing) is taken into consideration, it is preferable to provide the first surface roughness region 181 in the range of 30% from the top dead center TDC to 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.

[0065] The structural example shown in Fig. 9 is the same as the structural example shown in Fig. 8, but further includes a change in thickness t of the first portion 210. Specifically, in a 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 continuously changing region 211 where the boundary changes continuously, and in particular has a straight portion 212 where the boundary changes linearly.

[0066] 9(a), wall surface 232A is a straight portion 212 that is obliquely linear (inclined) in cross section, and the thickness t of 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 first region 171 with a large thermal resistance Rt, and the lower side (bottom dead center BDC side) is second region 172 with a smaller thermal resistance Rt than first region 171. Furthermore, on wall surface 215, the region where first region 171 is provided is first surface roughness region 181 with a large surface roughness value, and the region where second region 172 is provided is 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, 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 burns 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.

[0067] 9(b), the wall surface 232A is a straight portion 212 that is obliquely 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 a first region 171 with a large thermal resistance Rt, and the upper side (top dead center TDC side) is a second region 172 with a smaller thermal resistance Rt than the first region 171. Furthermore, on the wall surface 215, the region where the first region 171 is provided is a first surface roughness region 181 with a large surface roughness value, and the region where the second region 172 is provided is a second surface roughness region 182 with a small surface roughness value.

[0068] 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, so that the thermal resistance Rt on the top dead center TDC side is made 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 fuel burns in the combustion chamber (i.e., when the piston 190 is near the top dead center TDC), and promotes 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 the combustion timing (i.e., the heat generation timing) is taken into consideration, 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.

[0069] The continuously changing region 211 where the thickness of the first portion 210 changes is not limited to the straight line portion 212, and may be provided in a curved shape. Furthermore, the thickness of the first portion 210 may not change continuously, but may be discontinuous with a step.

[0070] In the structural example shown in FIG. 10, in order to provide a difference in the thermal resistance Rt for each region of the first portion 210, different adhesives are used in the adhesive layer 300 used to attach the resin block 200 to the metal block 140 (or the cylinder liner 120).

[0071] 10(a), 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 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 that on the bottom dead center (BDC) side and the thermal resistance Rt is increased, it is possible to achieve high thermal efficiency by preventing the heat generated during combustion from escaping to the water jacket 232 when the fuel is combusted in the combustion chamber (i.e., when the piston 190 is near top dead center (TDC)).

[0072] In the structure of FIG. 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 adhesive being thicker than the second adhesive layer region 302, and the thermal resistance Rt is larger. By adopting a configuration in which the thermal resistance Rt on the top dead center TDC side is small, it is possible to release heat 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), and to promote cooling. This is effective in an engine in which the temperature in the combustion chamber becomes high during combustion and knocking is likely to occur.

[0073] 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.

[0074] Although the embodiments of the present invention have been described above with reference to the drawings, these are merely examples of the present invention, and various configurations other than those described above may also be adopted. For example, in the above embodiment, the resin block 200 is applied to a two-cylinder engine (engine block 10), but the resin block 200 may be applied to a single-cylinder engine or an engine with three or more cylinders, regardless of the number of cylinders. [Explanation of symbols]

[0075] 10 Engine block 20 Cylinder head 100 Base Block 110 Block member 120 Cylinder liner 120a iron layer 120b Aluminum layer 122 Metal outer surface 140 Metal Block 142 Block outer surface 150 void 152 Water jacket (cooling water channel) 171 First Area 172 Second Area 181 First surface roughness region 182 Second surface roughness region 200 Resin Block 210 Part 1 211 Continuously Changing Region 212 Straight section 213 Curved section 214 Boundary 215 Wall 216 Wall unevenness 220 Part 2 230 void 232 Water jacket (cooling water channel) 232A Wall 300 adhesive layer 301 first adhesive layer region 302 second adhesive layer area

Claims

1. 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.

2. 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.

3. 3. The engine block according to claim 1, further comprising an adhesive layer provided between the first portion of the resin block and the metal block.

4. 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.

5. 5. The engine block according to claim 1, wherein a 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.

6. 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 density of the cured thermosetting resin forming the first portion of the resin block is 2.2 g / cm ３ 7. An engine block according to claim 1, wherein:

8. 8. The engine block according to claim 1, wherein a glass transition point (Tg) of a cured product of the thermosetting resin forming the first portion of the resin block is 160° C. or higher.

9. 9. The engine block according to claim 1, wherein the cured product of the thermosetting resin forming the first portion of the resin block is made of a phenolic resin.

10. 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 on the top dead center side of the second adhesive layer region. Engine block.

11. A resin block constituting the engine block according to any one of claims 1 to 10.

12. 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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