JP2006274919A - Cylinder block - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cylinder block implementing desired cooling performance. <P>SOLUTION: The cylinder block 1 has a cylinder bore 11 brought into slide-contact with a piston 12 and constituting a combustion chamber 11, and a water jacket 3 cooling the cylinder bore 11. The cylinder block 1 is provided with a plurality of movable fins 3 abutted on/separated from an outer periphery 4 of the cylinder bore. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a cylinder block, and more particularly to a cylinder block having a water jacket.

Conventionally, the cylinder block is disclosed by Unexamined-Japanese-Patent No. 2004-92547 (patent document 1) and Unexamined-Japanese-Patent No. 2002-256964 (patent document 2), for example.
JP 2004-92547 A JP 2002-256964 A

  In Patent Document 1, the water jacket of the cylinder block of the head gasket is provided with a space between the gasket and the cooling water flow control plate, and the control plates are joined to each other by opening and closing the thermo valve according to the water temperature. A technique for preventing deformation due to thermal expansion of the cylinder wall by bending and abutting and controlling the cooling water is disclosed. Patent Document 2 discloses a cylinder block that can equalize the warm-up property and the temperature of the bore wall.

  In the above-described configuration, the flow of the cooling water in the vertical direction of the cylinder cannot be controlled, and thus there is a problem that it is difficult to correct the temperature difference between the upper and lower portions of the cylinder.

  Accordingly, the present invention has been made to solve the above-described problems, and an object of the present invention is to provide a cylinder block capable of adjusting the heat radiation amount corresponding to the operating state of the internal combustion engine.

  A cylinder block according to the present invention has a cylinder bore that slides with a piston of an internal combustion engine and that constitutes a combustion chamber, and a water jacket that cools the cylinder bore. One or more fins are arranged.

  In the cylinder block configured as described above, it is possible to control the heat state of the cylinder bore or the variable fin by moving in response to the cold / warm-up state of the internal combustion engine.

  Preferably, the lower end of the cylinder bore serves as a fulcrum for the movable fin. In this case, during the warm-up process such as cold start, the entire fin can come into contact with the bore, and the oil warm-up can be quickly increased by improving the warm-up performance of the bore, and the friction can be reduced. it can. In addition, after the warm-up is finished, the upper part of the movable fin is separated from the bore like a bow, the cooling water passage at the upper part of the bore is widened, the heat cooling efficiency in the vicinity of the combustion chamber can be improved, and the deformation of the bore can be suppressed. .

  Preferably, the movable fin has a snap mechanism that bends in the middle thereof. In the cylinder block configured as described above, the temperature of the lower portion of the bore rises due to the sliding frictional heat of the piston ring when the load is high and the rotation speed is high, so that the cooling water can be flowed to the lower portion.

  Preferably, the movable fin has a lower thermal conductivity than the aluminum-based metal.

  Preferably, the movable fin is deformed so that the amount of heat released from the cylinder bore to the cooling water increases as the amount of heat generated in the cylinder bore increases, and a gap is formed between the movable fin and the outer periphery of the cylinder bore.

  According to this invention, it is possible to provide a cylinder block capable of changing the cooling state in accordance with the operating state of the internal combustion engine.

  Embodiments of the present invention will be described below with reference to the drawings. In the following embodiments, the same or corresponding parts are denoted by the same reference numerals, and description thereof will not be repeated.

(Embodiment 1)
FIG. 1 is a cross-sectional view of a cylinder block according to Embodiment 1 of the present invention. Referring to FIG. 1, a cylinder block 1 according to Embodiment 1 of the present invention slides with a piston 12 of an internal combustion engine and forms a combustion chamber 11, and a water for cooling the cylinder bore 4. A plurality of movable fins 3 having a jacket 2 and abutting and separating from the outer peripheral surface 13 of the cylinder bore 4 depending on the water temperature state are provided. The movable fin 3 has a snap mechanism 31 that bends in the middle thereof. The movable fin 3 has a lower thermal conductivity than the aluminum-based metal. The movable fin 3 is deformed so that the amount of heat released from the combustion chamber 11 to the cooling water 101 increases as the amount of heat generated in the combustion chamber 11 increases, and a gap is formed between the movable fin 3 and the outer peripheral surface 13 of the cylinder bore 4.

  The combustion chamber 11 in the cylinder block 1 has a cylindrical shape, and fuel explosion occurs in this region, and this explosion force is transmitted to the piston 12.

  The piston 12 reciprocates in the combustion chamber 11 to convert the explosive force into reciprocating motion, and this reciprocating motion is converted into rotational force by the connecting rod and the crankshaft.

  In this embodiment, the type of engine is not particularly limited. For example, the fuel exploding in the combustion chamber 11 can burn various fuels such as gasoline and light oil. That is, the present invention can be applied to both gasoline engines and diesel engines. Furthermore, regarding the arrangement position of the piston in the engine, the present invention can be applied to various engines such as a series type, a V type, a W type, and a horizontally opposed type.

  A cylinder bore 4 is arranged on the outer periphery of the piston 12 so as to surround the piston 12.

  The cylinder bore 4 is a member that slides with the piston ring of the piston 12, and is made of an aluminum alloy, for example, from the viewpoint of improving heat dissipation (thermal conductivity). Moreover, when raising the intensity | strength of the cylinder bore 4, cast iron may be arrange | positioned in the surface facing the piston 12 among the cylinder bores 4, and the outer periphery may be covered with an aluminum alloy. Further, in the case of an internal combustion engine that requires particularly high strength, the cylinder bore 4 may be made of cast iron.

  The cylinder bore 4 is a cylindrical region surrounding the combustion chamber 11, the inner peripheral surface thereof faces the piston 12, and the outer peripheral surface 13 is in contact with the movable fin 3. A water jacket 2 is provided on the outer periphery of the cylinder bore 4. Cooling water 101 flows through the water jacket 2, and the cooling water 101 takes away the heat generated from the cylinder bore 4. The cooling water 101 acts as a cooling medium and does not have to be water, and may be cooled with a long life coolant, oil, or the like.

  The water jacket 2 is a refrigerant passage and is a space surrounded by the outer peripheral surface 13, the bottom surface 15, and the water jacket wall surface 14 of the cylinder bore 4. The water jacket 2 is opened on the upper side of the water jacket 2, that is, in the vicinity of the deck surface 18, and the cylinder block 1 according to this embodiment is a so-called open deck type cylinder block. The cylinder block 1 is not limited to the open deck type, and a closed type (the water jacket 2 is not opened on the deck surface 18) can be used for the cylinder block 1 that requires higher strength. Cooling water 101 is supplied to the water jacket 2 from the water pump, and the cooling water flows through the water jacket 2 to absorb the heat of the cylinder bore 4 and then moves to the head side to cool each element constituting the head. It is. The water jacket 2 extends from the upper end 21 to the lower end 22 of the cylinder bore 4 and has a shape surrounding the cylinder bore 4.

  A movable fin 3 is housed in the water jacket 2. The movable fin 3 is a shielding plate whose form can be changed according to temperature, and prevents the cooling water 101 from directly hitting the outer peripheral surface 13 of the cylinder bore 4. In the low temperature state shown in FIG. 1, the outer peripheral surface 13 of the cylinder bore 4 is covered with the movable fin 3.

  In the cooling structure of the cylinder block 1 in which the water jacket 2 is continuously provided on the outer periphery of the cylinder bore 4 to supply the cooling water 101 as a cooling medium to equalize the bore wall temperature, the cylinder block is provided in the water jacket 2. The movable fins 3 are formed separately. Moreover, the movable fin 3 may be provided in the cylinder block 1 itself or a water jacket formed integrally from the cylinder block 1. The movable fin 3 has a bimetal structure and opens and closes according to the wall temperature of the cylinder bore 4 and the cooling water temperature.

  2 to 4 are sectional views of the cylinder block shown for explaining the operation of the movable fin. Referring to FIG. 2, at the time of warm-up when the temperature of the outer peripheral surface 13 of the cylinder bore 4 and the temperature of the cooling water 101 are low, the movable fin 3 is closed and heat dissipation from the cylinder bore 4 to the cooling water 101 is shielded.

  Referring to FIG. 3, at the end of warm-up when the temperature of cooling water 101 and the temperature of outer peripheral surface 13 of cylinder bore 4 are increased, movable fin (variable fin) 3 is opened and heat radiation from cylinder bore 4 to cooling water 101 is started. . However, during normal operation, the upper end 21 (in the vicinity of the combustion chamber) of the cylinder bore 4 becomes high temperature, so that the movable fin 3 is restrained by the bottom surface 15 of the water jacket 2 so that the upper flow path becomes wider.

  Referring to FIG. 4, at a higher load and a higher rotation, the temperature of the lower portion of cylinder block 1 rises due to the sliding frictional heat of the piston ring and oil ring. For this reason, the movable fin 3 is provided with a snap mechanism. When the tip of the movable fin 3 presses against the wall surface of the water jacket 2 and the load on the movable fin 3 increases, the lower flow path of the cylinder bore 4 expands. At this time, the movable fin 3 has a snap mechanism 31 and the movable fin 3 is bent around the snap mechanism 31.

  5 and 6 are diagrams showing the configuration of the movable fin. 5 and 6, the movable fin 3 has a structure in which a coating 3b having a low thermal conductivity is applied to a bimetal 3a, and an end is fixed by a restraining tool 3c. However, the bimetal 3a is not indispensable, and any material can be used as long as it senses and deforms to achieve the target deformation. As the bimetal 3a, a highly versatile bimetal such as TM1 and TM2 (JIS standard C2530) is used. As the paint 3b, a silicon-based or fluorine-based paint is used. A metal or resin having a thermal expansion coefficient close to that of aluminum is used for the restraining tool 3c. The restraining tool 3c has a shape along the outer periphery of the cylinder bore so that the fins are evenly arranged around the cylinder bore. As shown in FIG. 6, a plurality of bimetals 3a are attached to an arc-shaped restraining tool 3c along the outer periphery of the cylinder bore so as to surround the outer periphery of the cylinder bore. The movable fin 3 can be deformed with the lower end of the bore as a fulcrum.

  In the cylinder block 1 configured as described above, as shown in FIGS. 2 to 3, the movable fin 3 is deformed according to the temperature of the cooling water 101 and the temperature of the outer peripheral surface 13 of the cylinder bore 4, and the cooling water 101 is transferred from the cylinder bore 4. Since the amount of heat released to can be adjusted, a desired cooling state can be realized.

  That is, in the present invention, the warm-up property and the uniformity of the bore ambient temperature can be improved. Regarding the warm-up property, the conventional cylinder block has a problem that the warm-up property is poor because the heat generated in the combustion chamber is taken away by the cooling water. On the other hand, in the present invention, the outer peripheral surface 13 of the cylinder bore 4 is covered with the movable fin 3 as shown in FIG. Thereby, the heat dissipation at the time of warming up can be prevented and the warming up property can be improved.

  Further, regarding the uniformity of the bore ambient temperature, due to the distortion of the bore system due to the local temperature rise of the cylinder bore 4, the non-uniform deformation in the vertical direction of the cylinder due to the temperature rise of the upper part of the cylinder bore wall, etc. There is a problem that the followability of the piston ring is reduced, and oil consumption and oil deterioration occur. In contrast, in the present invention, as shown in FIGS. 3 and 4, during normal operation, a gap is formed between the outer peripheral surface 13 of the cylinder bore 4 and the movable fin 3 in the upper portion of the cylinder bore 4 as shown in FIG. 4. Thus, heat dissipation from the combustion chamber 11 is promoted. Further, at the time of high load and high rotation, a large gap is formed in the lower part of the cylinder bore 4 in order to dissipate the frictional sliding heat generated by the piston 12, and the heat in this part is dissipated. As a result, the uniformity of the bore ambient temperature can be further improved. That is, in the present invention, the movable fin 3 is provided around the cylinder bore 4 of the cylinder block 1 to suppress the exhaust heat from the cylinder to the cooling water when the engine is cold, and to promote warm-up. It actively controls the temperature and controls the deformation of the bore wall.

(Embodiment 2)
FIG. 7 is a plan view of a cylinder block according to the second embodiment of the present invention. FIG. 8 is a side view of the cylinder block as seen from the direction indicated by the arrow VIII in FIG. Referring to FIG. 7, in cylinder block 1 according to the second embodiment of the present invention, cylinder block according to the first embodiment in that movable fin 3 extends along the circumferential direction of cylinder bore 4. Different from 1. In the first embodiment, the movable fin 3 is disposed so as to extend in the axial direction of the cylinder bore 4. The movable fin 3 is disposed in the water jacket 2 and, when cold, has an arc shape along the wall surface of the cylinder bore 4 as indicated by a solid line in FIG. The structure of the movable fin 3 is the same as that of the first embodiment and is a bimetal structure. The movable fin opens and closes according to the temperature of the cylinder bore 4 and the cooling water temperature. The movable fins 3 are arranged in a horizontal direction with respect to the cylinder bore 4 and are attached at predetermined intervals in the radial direction of the cylinder bore 4. A head bolt 5 is attached to the cylinder block 1, and the head bolt 5 fixes the cylinder block 1 and the cylinder head. Referring to FIG. 8, a plurality of belt-like movable fins 3 are fixed to the outer periphery of cylinder bore 4 of cylinder block 1. In this embodiment, the movable fins 3 are arranged so as to be orthogonal to the axial direction of the cylinder bore 4, but the movable fins 3 may be arranged so as to be inclined with respect to the axial direction of the cylinder bore 4. Further, the inclination angle in that case is not particularly limited.

  Next, the operation of the movable fin 3 will be described. At the time of warming up, the movable fin 3 is closed, and heat radiation from the cylinder bore 4 to the cooling water 101 is cut off. Specifically, the movable fin 3 is located at a position indicated by a solid line in FIG. 7, and most of the outer peripheral surface of the cylinder bore 4 is covered with the movable fin 3.

  After the warm-up is completed, the movable fin 3 moves to the position indicated by the dotted line, the movable fin 3 is opened, and heat dissipation from the cylinder bore 4 to the cooling water 101 is started. However, the roundness of the cylinder bore 4 can be improved by positively controlling the temperature distribution in the radial direction of the cylinder bore 4 using the opening shape of the movable fin 3. For example, the movable fins 3 are arranged at intervals of 90 degrees, and the cooling water 101 is positively passed through a portion stretched by tightening the head bolt 5 or the like. To improve the roundness of the bore. Further, in the Siamese type multi-cylinder engine, the roundness of the bore can be improved by positively widening the flow path between the cylinder bores having low cooling performance and improving the cooling performance from other portions. The configuration of the movable fin 3 is not limited to that shown in the embodiment, and may be anything that can be varied according to a preset temperature. Further, the arrangement position and the number of arrangement of the movable fins 3 are not particularly limited.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  The present invention can be used in the field of internal combustion engines.

It is sectional drawing of the cylinder block according to Embodiment 1 of this invention. It is sectional drawing of the cylinder block shown in order to demonstrate operation | movement of a movable fin. It is sectional drawing of the cylinder block shown in order to demonstrate operation | movement of a movable fin. It is sectional drawing of the cylinder block shown in order to demonstrate operation | movement of a movable fin. It is a figure which shows the structure of a movable fin. It is a figure which shows the structure of a movable fin. It is a top view of the cylinder block according to Embodiment 2 of this invention. It is the side view of the cylinder block seen from the direction shown by arrow VIII in FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Cylinder block, 2 water jacket, 3 movable fin, 4 cylinder bore, 5 head bolt, 11 combustion chamber, 13 outer peripheral surface, 14 water jacket wall surface, 15 bottom face, 21 upper end, 22 lower end, 101 cooling water.

Claims (5)

A cylinder bore that slides with the piston of the internal combustion engine and forms a combustion chamber;
A cylinder block having a water jacket for cooling the bore,
A cylinder block in which one or a plurality of movable fins that contact and separate from the outer periphery of the cylinder bore depending on the water temperature state are arranged.   The cylinder block according to claim 1, wherein a lower end portion of the cylinder bore is a fulcrum of the movable fin.   The cylinder block according to claim 1, wherein the movable fin has a snap mechanism that bends in the middle thereof.   The cylinder block according to claim 1, wherein the movable fin has a lower thermal conductivity than an aluminum-based metal.   2. The movable fin according to claim 1, wherein the movable fin is deformed so that a heat radiation amount from the cylinder bore to the cooling water increases as a heat generation amount in the cylinder bore increases, and a gap is formed between the movable fin and the outer periphery of the cylinder bore. Cylinder block.

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