Cylinder block, engine and vehicle

Abstract

To provide a cylinder block, an engine, and a vehicle capable of easily forming a cylinder bore that is capable of reducing friction.SOLUTION: A cylinder block according to one embodiment of the present disclosure comprises a cooling jacket in which a cylinder part is formed and which has a coolant chamber formed on an outer peripheral part of the cylinder part. The coolant chamber is arranged at a position in a depth direction of the cylinder part that is shallower than a position that is 40% of a depth dimension of the cylinder part.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a cylinder block, an engine, and a vehicle. [Background technology]

[0002] In internal combustion engines used in automobiles, trucks, and other vehicles, the cylinder bores formed in cylinder components such as the cylinder block are subject to significant deformation due to the tightening of head bolts and thermal loads. This deformation can increase friction loss with the pistons, resulting in poor fuel economy.

[0003] To address these issues, advanced honing techniques have been developed in recent years, and it is now necessary to hone the cylinder bore to achieve an ideal shape for actual operation. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 8-61139 Summary of the Invention [Problem to be solved by the invention]

[0005] The present disclosure has been made in consideration of the above-mentioned problems, and aims to provide a cylinder block, an engine, and a vehicle that can easily form a cylinder bore that can reduce friction. [Means for solving the problem]

[0006] A cylinder block according to one embodiment of the present disclosure includes a cylinder portion formed therein and a cooling jacket having a coolant chamber formed on an outer periphery of the cylinder portion, The coolant chamber is disposed at a position shallower than a position that is less than 40% of the depth dimension of the cylinder portion in the depth direction of the cylinder portion. [Effects of the Invention]

[0007] According to the present disclosure, it is possible to provide a cylinder block, an engine, and a vehicle that can easily form a cylinder bore that can reduce friction. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is an explanatory diagram showing a vehicle according to a first embodiment of the present invention; [Figure 2] 1 is an explanatory diagram showing a schematic configuration of an engine according to a first embodiment of the present invention. [Figure 3] 1 is a cross-sectional view of a cylinder block according to a first embodiment of the present invention. [Figure 4] 1 is a plan view of a cylinder block according to a first embodiment of the present invention; [Figure 5] 4 is a three-dimensional graph showing the results of a simulation of deformation that occurs in the cylinder bores according to Example 1 and Comparative Example 1 during actual operation. [Figure 6] 4 is a three-dimensional graph showing the results of a simulation of deformation that occurs in the cylinder bores according to Example 1 and Comparative Example 1 during actual operation. [Figure 7] 4 is a graph showing the shapes of cylinder bores according to Example 1 and Comparative Example 1 during actual operation. [Figure 8] FIG. 2 is an explanatory diagram showing the shapes of cylinder bores according to Example 1 and Comparative Example 1 during actual operation. [Figure 9] 3 is a graph showing FMEP (Friction Mean Effective Pressure) due to sliding between a cylinder bore and a piston skirt in Example 1 and Comparative Example 1. [Figure 10] 4 is a graph showing noise characteristics of the cylinder blocks according to Example 1 and Comparative Example 1. [Figure 11] FIG. 10 is an explanatory diagram showing the shape of a cylinder block according to a second embodiment and deformation during operation. [Figure 12] FIG. 10 is an explanatory diagram showing the shape of a cylinder block according to Comparative Example 2 and deformation during operation. [Figure 13]10 is a three-dimensional graph showing the results of a simulation of deformation that occurs during actual operation of the cylinder block according to Comparative Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0009] The following describes the configuration of a vehicle 1 and a cylinder block 10 serving as a cylinder member according to an embodiment of the present disclosure, with reference to the drawings. FIG. 1 is an explanatory diagram showing a vehicle according to an embodiment of the present disclosure, and FIG. 2 is an explanatory diagram showing a schematic configuration of an engine. FIGS. 3 and 4 are a cross-sectional view and a plan view of the cylinder block. In the drawings, X, Y, and Z respectively represent three directions that are perpendicular or intersecting each other. Note that in each drawing, the configuration is enlarged, reduced, or omitted as appropriate for ease of explanation. In this embodiment, an example is shown in which the cylinder block 10 is arranged in an orientation in which a first direction along the direction of reciprocation of the pistons 13 is the Z axis, a second direction in which the cylinders are aligned is the Y axis, and a third direction along the thrust and anti-thrust sides is the X axis.

[0010] 1, a vehicle 1 includes an engine 2, a transmission 3, and, for example, four or more wheels 4. When a piston 13 of the engine 2 of the vehicle 1 is driven, driving force is transmitted to the wheels 4 via the transmission 3.

[0011] The engine 2 includes a cylinder block 10 , a plurality of pistons 13 housed in the cylinder block 10 , a crankshaft 14 , and a cylinder head 15 fastened to the cylinder block 10 .

[0012] The cylinder block 10 according to this embodiment is, for example, a multi-cylinder in-line engine in which multiple cylinders are arranged in series. The cylinder block 10 is a so-called closed deck type in which a cylinder head 15 is fastened and fixed by head bolts to the opening side of multiple parallel-arranged cylinder sections 111. Note that the cylinder block 10 is not limited to in-line engines. For example, it may be applied to a V-type engine or a single-cylinder engine.

[0013] The cylinder block 10 has a block body 11 in which a plurality of cylinder portions 111 are formed, and a crankcase portion 12 provided below the block body 11.

[0014] The block body 11 has a plurality of cylinder portions 111, which are cylindrical spaces that open to one side in the first direction. The lower end of the block body 11 is integrally connected to a crankcase portion 12 that houses a crankshaft 14.

[0015] In this embodiment, the multiple cylinder portions 111 are arranged along the second direction, which is the extension direction of the crankshaft 14. A piston 13 is arranged inside each cylinder portion 111 so as to be able to reciprocate along the first direction. The inner wall surface of the cylinder portion 111 forms a cylinder bore (bore portion) 20, which serves as a sliding surface for the piston.

[0016] Here, if the reciprocating direction of the piston 13 is defined as a first direction, and the direction in which the crankshaft 14 extends, which is perpendicular to or intersects with the first direction, is defined as a second direction, then one side of a third direction, which is perpendicular to or intersects with the first and second directions, is defined as the thrust side, and the other side is defined as the anti-thrust side. For example, when the piston 13 reciprocates in the first direction, a so-called oscillating motion occurs in which the piston 13 tilts in each cylinder portion 111 of the block body 11, and the piston 13 hits the inner wall of the cylinder portion 111 and receives lateral pressure. At this time, the direction in which the piston 13 receives lateral pressure when it is subjected to a load due to combustion immediately after top dead center is defined as the thrust side, and the opposite direction is defined as the anti-thrust side.

[0017] A cooling jacket 17 that accommodates a coolant is formed on the outer periphery of the cylinder portion 111 of the cylinder block 10. For example, the cooling jacket 17 is formed in the upper part of the block body 11 and has a coolant chamber 171 through which the coolant flows. For example, the region where the cooling jacket 17 is formed is located at a position shallower than 40% of the depth of the cylinder portion 111 of the block body 11, that is, in a region on one side in a first direction, which is the depth direction. For example, the coolant chamber 171 is formed in the block body 11 in a region on one side of a position that is 40% of the depth to the bottom 111a, which is the lowest side of the cylinder portion 111, that is, the end on the other end side in the first direction. For example, in the first direction, the other end 171a of the coolant chamber 171 is disposed on one side of the bottom 111a of the cylinder portion 111 of the block body 11, and the dimension from the end face 11a on one side of the block body 11 in the first direction to the other end 171a of the coolant chamber 171 is smaller than 40% of the dimension from the end face 11a to the bottom 111a of the cylinder portion 111. In other words, the jacket depth D is equal to or greater than the cylinder depth H × 0.4.

[0018] Furthermore, a plurality of fastening holes 18 into which head bolts for fastening the cylinder head are fastened are formed at predetermined locations on the outer periphery of each cylinder portion 111 of the block body 11 on both sides in the third direction. For example, the fastening holes 18 are formed from the end face 11a on one side of the block body 11 in the first direction toward the other side in the first direction to a predetermined depth. For example, the fastening holes 18 have female threads formed on their inner surfaces. The fastening holes 18 are provided on both sides in the third direction, which are the thrust direction side and the counter-thrust direction, of each cylinder portion 111 of the block body 11.

[0019] As an example, the head bolts and fastening holes 18 are provided at multiple locations in the circumferential direction of each cylinder portion 111, for example, three locations on each side in the thrust direction and anti-thrust direction, arranged at equal intervals. In the example shown in FIG. 2 , fastening holes 18 are formed at a total of six locations: two points in the thrust direction and anti-thrust direction, and four points offset from the two points at the same angle on both sides in the circumferential direction. For example, when viewed from the cylinder head 15 side, a pair of main fastening holes 181 are provided on or near imaginary lines extending from the center of the cylinder portion 111 to the thrust side and anti-thrust side, respectively, and sub-fastening holes 182 are formed on both sides in the circumferential direction from the pair of main fastening holes 181. Here, the fastening holes 18 are formed to a depth deeper than the coolant chamber 171.

[0020] For example, the fastening hole 18 is formed at a position shallower than the bottom 111a of the cylinder portion 111 of the block body 11. In other words, the bottom 18a, which is the end portion on the other axial side and the deepest position of the fastening hole 18, is located on one side of the bottom 111a of the cylinder portion 111.

[0021] In the cylinder block 10, a boss portion 19 is formed on the outer surface of the block body 11 around a fastening hole 18 in which a head bolt is disposed, where the boss portion 19 protrudes outward.

[0022] For example, the boss portion 19 has an arc-shaped vertical wall that covers the outer periphery of the head bolt, and the boss portion 19 forms a part of the block body 11 into a double-wall structure. For example, the other axial end of the boss portion 19 is located below the bottom 18a of the fastening hole 18, for example, at a position shallower than the bottom 111a. In other words, the dimension of the boss portion 19 in the depth direction is smaller than the depth of the cylinder portion 111. For example, the protruding portions of the boss portions 19 for the head bolts on the thrust side and anti-thrust side reach the middle of the cylinder portion 111. In other words, the block body 11 has a stepped portion 112 formed on the outer periphery near the bottom 111a of the cylinder portion 111, where the thickness changes so that the lower side is thinner. That is, in this embodiment, the boss portion 19 is not continuous with the skirt portion 121 which widens again in the crankcase portion 12, and a recess is disposed between the boss portion 19 and the skirt portion 121 of the crankcase portion 12 near the bottom of the cylinder portion 111, where the outer surface is recessed inward and thin-walled.

[0023] In the cylinder block 10 configured as described above, the block body 11 in which the cylinder portion 111 is formed has, in the first direction, a first area in which the coolant chamber 171 is formed at the top, a second area that is thick at the lower end of the boss portion 19, and a third area that has a step below the boss portion 19 and is thin-walled on the lower side.

[0024] The cylinder head 15 is disposed on the cylinder block 10, facing the cylinder block 10, with a gasket interposed therebetween. For example, the cylinder head 15 has bolt holes through which head bolts pass, and is fastened onto the cylinder block 10 by the head bolts.

[0025] The crankcase portion 12 is connected to the other side of the block body 11. The crankcase portion 12 houses the crankshaft 14. For example, the crankcase portion 12 has a skirt portion 121 having an outer shape that widens downward. In this embodiment, the skirt portion 121 and the boss portion 19 are not continuous in the first direction, and a stepped portion 112 is disposed between the skirt portion 121 and the boss portion 19. The stepped portion 112 has a recess whose outer surface is recessed inward from the boss portion 19 and the skirt portion 121 and is configured to be thin-walled.

[0026] The piston 13 has a top portion on which a piston ring is provided on the upper side, and a skirt portion below the area where the piston ring is provided on the top portion. The piston 13 is connected to the crankshaft 14, and reciprocates in a first direction within the cylinder portion 111 as the crankshaft 14 rotates. The outer shape of the skirt of the piston 13 is configured in a so-called elliptical shape, with dimensions in the thrust direction and counter-thrust direction being larger than dimensions in a direction perpendicular to the thrust direction and counter-thrust direction.

[0027] The crankshaft 14 is disposed inside the crankcase portion 12, which is disposed on the other side of the block body 11 in the first direction. The crankshaft 14 is disposed along a second direction that is perpendicular to the direction of the cylinder axis along which the piston 13 reciprocates.

[0028] Here, the piston sliding speed increases when the position of the piston 13 is near the midpoint of its reciprocating motion in the cylinder portion 111. The friction generated between the skirt of the piston 13 and the sliding surface of the inner wall of the cylinder portion 111 increases as the piston sliding speed increases. Therefore, when the piston 13 reciprocates in the cylinder portion 111, the skirt friction increases when the piston 13 is near the midpoint of its reciprocating motion. For example, the skirt friction tends to increase where the piston sliding speed is highest. Therefore, by expanding this portion, friction can be effectively suppressed.

[0029] 5 to 10 show the deformation during operation of (a) a cylinder block 10A according to Example 1 of the present embodiment and (b) a cylinder block 110 according to Comparative Example 1. In FIGS. 5 to 10, (a) shows the cylinder block 10A according to Example 1, and (b) shows the cylinder block 110 according to Comparative Example 1. The cylinder block 10A has a cooling jacket 17 formed above the bottom 111a of the cylinder section 111 of the block body 101, at a depth less than 40% of the original depth. On the other hand, the cylinder block 110 according to Comparative Example 1 has a cooling chamber 1071 of the cooling jacket 107 extending to the vicinity of the bottom 1011a of the cylinder section 1011 of the block body 101. That is, in Comparative Example 1, the cooling chamber 1071 of the cooling jacket 107 extends to the lower end of the bore 120 of the cylinder section 1011. In the manufacturing method of the cylinder blocks 10A, 110, the inner walls of the cylinder portions 111, 1011 are honed to have the same profile, for example, a cylindrical shape with a constant diameter, as a honing step.

[0030] Generally, cylinder bores formed in cylinder components such as cylinder blocks of engines used in vehicles such as automobiles and trucks are subject to significant deformation during operation (use) due to the tightening of head bolts and thermal loads, as shown in Figure 13, for example.

[0031] 5 and 6 show the results of simulating the deformation of the cylinder bores 20, 120 caused by heat and fastening loads during actual operation for the cylinder block 10A according to Example 1 and the cylinder block 110 as Comparative Example 1, in which the cooling jacket 107 is formed up to near the bottom of the cylinder section 1011. Fig. 5 is a three-dimensional graph showing the simulation results of deformation caused by heat and fastening loads during actual operation.

[0032] Fig. 7(a) shows the shapes of the bores 20, 120 of the four cylinders during operation in the cylinder block 10A of Example 1 and the cylinder block 110 of Comparative Example 1. Fig. 8 is a graph showing the shapes of the bore 20 of the cylinder block 10A of Example 1 and the bore 120 of the cylinder block 110 of Comparative Example 1, with the vertical axis representing the height dimension (depth dimension) and the horizontal axis representing the radial dimension.

[0033] 5(b) to 8(b), in the cylinder block 110 of Comparative Example 1, the cooling jacket 17 is formed deep, and therefore, during operation, the cylinder portion 111 is deformed in the inner diameter direction and constricted at the bottom of the jacket 17. That is, the cylinder portion 111 is deformed so that the inner diameter becomes smaller at the bottom and becomes larger at the top of the cylinder portion 111.

[0034] On the other hand, as shown in Figures 5(a) to 8(a), in the cylinder block 10A of Example 1 of this embodiment, the cooling jacket 17 is configured at a shallow position, so deformation is suppressed in the central and lower parts of the cylinder section 111, and the inner wall is deformed inward at the upper part of the cylinder section 111. In other words, deformation in which the bore 20 is constricted inward can be induced at the height of the end part 171a of the coolant chamber 171 of the cooling jacket 17. On the other hand, it can be seen that if the cooling jacket 17 is shortened, the constriction deformation from the middle to lower part of the cylinder section 111 can be eliminated.

[0035] FIG. 9 is a graph showing FMEP (Friction Mean Effective Pressure) due to sliding between the cylinder bore and piston skirt of the cylinder block 10A of Example 1 and the cylinder block 110 of Comparative Example 1. FIG. 9 shows a simulation of the friction between the piston and the sliding surface when the piston 13 strokes for the deformed cylinder bores 20, 120. Note that the simulation conditions are the same for Comparative Example 1 and Example 1. As can be seen from the graph in FIG. 9, the FMEP in Example 1 is almost half of the FMEP in Comparative Example 1. These data show that the cylinder bore 20 according to this embodiment reduces friction with the piston 13. Therefore, the cylinder bore 20 can reduce friction and the amount of deformation compared to the cylinder bore 120.

[0036] FIG. 10 is a graph showing acceleration amplitude as noise characteristics of the cylinder blocks according to Example 1 and Comparative Example 1. In FIG.

[0037] 9 and 10, in Example 1, friction is reduced and slap due to piston oscillation is suppressed compared to Comparative Example 1. Therefore, improvement in vibration noise is expected.

[0038] Next, the position of the boss portion 19 and deformation during operation will be described with reference to Figures 11 and 12. Figure 11 shows the results of a simulation of the change in shape of the cylinder bore 20 of the cylinder block 10 of this embodiment during operation. Figure 12 shows the results of a simulation of the change in shape of the cylinder bore 220 of the cylinder block 210 according to Comparative Example 2 during operation. In the cylinder block 210 according to Comparative Example 2, the boss portion 19 extends downward and reaches the skirt portion 121.

[0039] 11 and 12, it can be seen that the cylinder block 10 according to this embodiment is deformed so that the middle of the bore 20 is wider due to the step below the boss portion 19 than the cylinder block 210 of Comparative Example 2. That is, the middle portion above the bottom 111a of the cylinder portion 111, which is the step below the boss portion 19 and serves as the piston chamber, is deformed outward and widened.

[0040] That is, according to this embodiment, the profile of the bore 20 can be set by adjusting the positions and depths of the fastening holes 18 and the cooling jacket 17. For example, by adjusting the position of the cooling jacket 17, it is possible to obtain a shape in which the upper and lower portions of the bore 20 are constricted. Furthermore, by setting the depth positions of the fastening holes 18 and the boss portions 19, it is possible to obtain a shape in which the middle portion is bulged. Therefore, it is possible to realize a profile of the bore 20 that bulges outward near the middle of the bore, where the sliding speed of the piston 13 is high, and friction can be reduced. Furthermore, by adjusting the thickness and strength of the walls of the cylinder block 10, it is possible to expect performance improvements without making expensive investments in machining equipment, etc.

[0041] According to the cylinder block 10 of this embodiment, by adjusting the position of the cooling jacket 17, the shape of the bore 20 can be controlled using existing processing equipment without expensive investment in processing equipment, etc., and friction performance can be improved. For example, a bore profile that bulges outward near the middle of the bore, where the piston sliding speed is high, is generally considered to reduce friction and improve engine performance. However, according to the above embodiment, by adjusting the position of the cooling jacket 17, a honing profile in which the pressurized portion bulges can be easily obtained, making it possible to set the shape of the cylinder bore 20 without using advanced honing techniques. Therefore, even in mass production, there is no need to replace processing equipment, and manufacturing costs can be reduced. Furthermore, as an example, by arranging the fastening holes 18 in the thrust direction and counter-thrust direction and adjusting the fastening state by the depth and position of the fastening holes 18, the shape of the bore can be controlled to effectively suppress friction in areas where friction with the skirt of the piston 13 is high. Furthermore, in the height direction, friction of the skirt tends to increase where the piston sliding speed is highest, so by expanding this portion, friction can be effectively suppressed.

[0042] The present invention is not limited to the above embodiment. For example, the number and arrangement of the fastening holes 18 are not limited to the above example and can be changed as appropriate. Furthermore, the number of cylinder portions 111 and the specific shape and arrangement of each component are not limited to the above example and can be changed as appropriate.

[0043] Although one embodiment of the present disclosure has been described above in detail, the present invention is not limited to the above embodiment and can be appropriately modified, improved, etc. The present invention is defined by the claims and includes all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0044] 1...vehicle, 2...engine, 3...transmission, 4...wheel, 10, 10A...cylinder block, 11...block body, 11a...end face, 12...crankcase portion, 13...piston, 14...crankshaft, 15...cylinder head, 17...cooling jacket, 18...fastening hole, 18a...bottom, 19...boss portion, 20...cylinder bore, 107...cooling jacket, 110...cylinder block, 111...cylinder portion, 101...block body, 111a...bottom, 112...step portion, 120...cylinder bore (bore), 121...skirt portion, 171...coolant chamber, 171a...end, 181...main fastening hole, 182...fastening hole, 210...cylinder block, 220...cylinder bore, 1011...cylinder portion, 1011a...bottom, 1071...cooling chamber.

Claims

1. a cooling jacket in which a cylinder portion is formed and which has a coolant chamber formed on the outer periphery of the cylinder portion; A cylinder block, wherein the coolant chamber is disposed at a position shallower than a position corresponding to 40% of the depth dimension of the cylinder portion in a depth direction of the cylinder portion.

2. 2. The cylinder block according to claim 1, wherein the cylinder portion has fastening holes at positions on the thrust side and anti-thrust side, into which head bolts are fastened.

3. 3. The cylinder block according to claim 2, wherein the fastening hole is disposed at a position deeper than a bottom of the coolant chamber in a depth direction of the cylinder portion.

4. A plurality of the cylinder portions are formed side by side, 3. The cylinder block according to claim 2, wherein a plurality of the fastening holes are formed on each of the thrust side and the anti-thrust side, which are on both sides of a direction intersecting a direction in which the plurality of cylinder portions are arranged.

5. The fastening hole is formed from one end face of the cylinder block toward the other end, In the depth direction of the cylinder portion, the other end of the fastening hole is located on one side of the bottom of the cylinder portion, The cylinder block has boss portions that protrude outward from outer surfaces of both sides of the cylinder portion outside the fastening hole, In a depth direction of the cylinder portion, one end of the boss portion is disposed at a position on one side of a bottom portion of the cylinder portion, 3. The cylinder block according to claim 2, wherein the cylinder block has a stepped portion whose outer surface is recessed inward at a position on the other side of the boss portion in the depth direction and on one side of a bottom of the cylinder portion.

6. A cylinder block according to any one of claims 1 to 5; a piston disposed within the cylinder portion; a cylinder head disposed opposite to and fastened to one side of the cylinder block.

7. A vehicle having the engine of claim 6.

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