JP2013160126A - Internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an internal combustion engine capable of cooling lubricating oil staying on an upper deck.SOLUTION: A cylinder head 30 is installed in a cylinder block 11 with bolts 60. Heat exchange members 70 for exchanging heat with lubricating oil staying on the upper deck 50 of the cylinder head 30 are co-fastened to the cylinder head 30 by the bolts 60.

Description

  The present invention relates to an internal combustion engine including a heat exchange member that exchanges heat with lubricating oil staying in an upper deck of a cylinder head.

  Conventionally, as this type of internal combustion engine, for example, an internal combustion engine described in Patent Document 1 has been proposed. In the cylinder head of this internal combustion engine, a plurality of fins are integrally provided on the cylinder head on the upper deck. As a result, the heat dissipation area of the upper deck is expanded, and the cooling efficiency of the lubricating oil staying on the upper deck is increased.

JP 2003-343346 A

  However, in the configuration in which such a fin is provided integrally with the cylinder head, it is necessary to design the mold of the cylinder head each time in consideration of the hot water around the fin, the heat radiation characteristics required for the internal combustion engine, and the like. Therefore, a significant increase in manufacturing cost is caused.

  The present invention has been made in view of such circumstances. An object of the present invention is to provide an internal combustion engine that can cool the lubricating oil staying on the upper deck with a simple configuration without changing the shape of the cylinder head.

In the following, means for achieving the above object and its effects are described.
According to the first aspect of the present invention, in the internal combustion engine in which the cylinder head is assembled to the cylinder block with the bolt, the heat exchange member that exchanges heat with the lubricating oil staying on the upper deck of the cylinder head is used for the cylinder by the bolt. The gist is that it is fastened to the head.

  According to the said structure, the heat exchange member is provided on the upper deck in the state fastened together by the cylinder head with the volt | bolt for assembling a cylinder head to a cylinder block. Therefore, the lubricating oil can be cooled through heat exchange between the heat exchange member and the lubricating oil staying on the upper deck. In addition, since the heat exchange member is attached to the cylinder head using bolts for assembling the cylinder head to the cylinder block, a dedicated bolt for installation or a new hole for bolts may be provided in the cylinder head. There is no need to do. Therefore, the lubricating oil staying on the upper deck can be cooled with a simple configuration without changing the shape of the cylinder head.

  According to a second aspect of the present invention, in the internal combustion engine according to the first aspect, the shaft portion of the bolt to which the heat exchange member is fastened is located between the water jacket and the combustion chamber of the cylinder head. Is the gist.

  According to the above configuration, the periphery of the bolt in the cylinder head and the shaft portion of the bolt are cooled by the cooling water flowing through the water jacket of the cylinder head. Here, the water jacket has a longer distance from the combustion chamber as compared with the case where the water jacket is disposed between the shaft portion of the bolt and the combustion chamber. It is not easily affected by heat and its temperature is maintained at a relatively low temperature. And since the axial part of a volt | bolt is cooled by such cooling water, the temperature rise of the heat exchange member which contacts this volt | bolt can be suppressed effectively, and the cooling efficiency of the lubricating oil stagnating on an upper deck is improved. To be able to.

  According to a third aspect of the present invention, in the internal combustion engine according to the first or second aspect, the heat exchange member has a state in which the back surface thereof is in surface contact with the upper deck and the back surface is separated from the upper deck. It is configured by a shape memory alloy plate that changes its shape according to temperature, and the edge of the heat exchange member is displaced in a direction away from the upper deck as the heat exchange member becomes hot. The gist.

  According to the above configuration, when the temperature of the heat exchange member becomes high through heat exchange with the lubricating oil, the edge of the heat exchange member is displaced in a direction away from the upper deck based on its shape memory characteristics, and the back surface of the heat exchange member A gap is formed between the upper deck and the upper deck. Then, the lubricating oil flows into this gap, and the lubricating oil comes into contact with the back surface of the heat exchange member. As a result, the contact area of the heat exchange member with the lubricating oil is increased, and the lubricating oil can be effectively cooled. On the other hand, when the temperature of the lubricating oil is low and the temperature of the heat exchanging member is also low, the back surface of the heat exchanging member comes into surface contact with the upper deck based on its shape memory characteristics. There is no heat exchange between the back surface of the replacement member and the lubricating oil. As a result, it is possible to suppress unnecessary cooling of the lubricating oil when the engine is cold.

  According to a fourth aspect of the present invention, in the internal combustion engine according to the first or second aspect, the heat exchange member is formed of a plate material, and a temperature is high between the heat exchange member and the upper deck. An expansion / contraction part is provided that extends to the extent that the edge of the heat exchange member is displaced in a direction away from the upper deck due to the expansion of the expansion / contraction part as the temperature of the lubricating oil rises.

  According to the said structure, when the temperature of lubricating oil becomes high, the edge part of a heat exchange member will be displaced to the direction away from an upper deck by expansion | extension of an expansion-contraction part. As a result, a gap is formed between the heat exchange member and the upper deck. Then, the lubricating oil flows into this gap, and the lubricating oil comes into contact with the back surface of the heat exchange member. As a result, the contact area of the heat exchange member with the lubricating oil is increased, and the lubricating oil can be effectively cooled. On the other hand, when the temperature of the lubricating oil is low, the back surface of the heat exchange member is in surface contact with the upper deck due to contraction of the expansion / contraction part. Therefore, such a gap is not formed, and heat exchange between the back surface of the heat exchange member and the lubricating oil is not performed. As a result, it is possible to suppress unnecessary cooling of the lubricating oil when the engine is cold.

1 is a cross-sectional view of an internal combustion engine according to an embodiment of the present invention. Sectional drawing which shows typically the cylinder head cut | disconnected by the 2-2 line in FIG. The perspective view of a heat exchange member. The graph which shows the temperature of the lubricating oil in each position of an internal combustion engine. (A) (b) is sectional drawing which shows typically a mode that a heat exchange member deform | transforms in another embodiment. Sectional drawing which expands and schematically shows a part of internal combustion engine in other embodiment. Sectional drawing which shows typically the heat exchange member in other embodiment. Sectional drawing which shows typically the heat exchange member in other embodiment.

DESCRIPTION OF EMBODIMENTS Hereinafter, an embodiment embodying an internal combustion engine of the present invention will be described with reference to FIGS.
As shown in FIG. 1, the cylinder block 11 of the internal combustion engine 10 is provided with a plurality of cylinders 13 for accommodating the pistons 12 (FIG. 1 shows one of them). In the cylinder block 11, a water jacket 14 through which cooling water flows is formed around each cylinder 13 so as to surround the cylinders 13.

The oil pan assembled to the lower part of the cylinder block 11 stores lubricating oil supplied to each part of the internal combustion engine 10.
On the other hand, the cylinder head 30 is assembled to the upper part of the cylinder block 11 using a plurality of bolts 60. The cylinder head 30, the cylinder 13 of the cylinder block 11, and the piston 12 define a combustion chamber 32 for combusting an air-fuel mixture composed of intake air that has flowed through the intake passage 31 and fuel injected from the injector.

  A head cover 33 is assembled on the upper portion of the cylinder head 30. In addition, in a space 34 surrounded by the cylinder head 30 and the head cover 33, an intake valve drive mechanism 36 that reciprocates an intake valve 35 that opens and closes an intake port 31a of the intake passage 31 and an exhaust port 37a of the exhaust passage 37 are provided. An exhaust valve drive mechanism 39 that reciprocates the exhaust valve 38 that opens and closes is provided.

  Further, the internal combustion engine 10 of the present embodiment pumps up the lubricating oil stored in the oil pan and supplies the lubricating oil to each lubricating portion of the internal combustion engine 10 such as the intake valve drive mechanism 36 and the exhaust valve drive mechanism 39. A pump is provided. Lubricating oil supplied to the intake valve driving mechanism 36 and the exhaust valve driving mechanism 39 stays on the upper deck 50 of the cylinder head 30 after being lubricated by the mechanisms 36 and 39. As shown in FIG. 2, a return oil passage 51 that opens to the upper deck 50 is formed in the cylinder head 30. The lubricating oil staying on the upper deck 50 is returned to the oil pan through the return oil passage 51. In FIG. 2, illustration of the intake valve drive mechanism 36 and the exhaust valve drive mechanism 39 is omitted.

  As shown in FIG. 1, the water jacket 65 is formed in the cylinder head 30 so as to surround the shaft portion 61 of each bolt 60. That is, the shaft portion 61 of the bolt 60 is positioned between the combustion chamber 32 and the water jacket 65, and the shaft portion 61 is adjacent to the water jacket 65 through the partition wall 66.

  Further, on the upper deck 50 of the cylinder head 30, a plurality of heat exchanging members 70 for cooling the lubricating oil temporarily staying on the upper deck 50 are provided. Each of these heat exchange members 70 is configured by a plate material having high thermal conductivity (for example, a metal plate such as copper). Such a heat exchange member 70 is fastened to the cylinder head 30 together with the above-described bolt 60 for assembling the cylinder head.

  As shown in FIGS. 2 and 3, a through hole 71 b is formed in the heat exchange member 70. The cylinder head 30 is assembled to the cylinder block 11 by the bolt 60 in a state where the shaft portion 61 of the bolt 60 is inserted into the through hole 71b. As a result, the surface 71 a of the heat exchange member 70 is in pressure contact with the head portion 62 of the bolt 60, and the back surface 71 c is in close contact with the upper deck 50.

  The heat exchanging member 70 is formed with a plurality of heat dissipating portions 72 in the form of strips at the ends thereof. The heat exchanging members 70 are fastened together with bolts 60 so that the heat radiating portions 72 protrude inside the upper deck 50. Each heat dissipating part 72 has a heat dissipating part 72A that is not bent at the base end and a heat dissipating part 72B that is bent at the base end. The heat radiating portions 72A and the heat radiating portions 72B are alternately arranged in the width direction.

  Next, the operation when the lubricating oil is cooled on the upper deck 50 will be described. FIG. 4 is a graph showing the temperature of the lubricating oil at each position P1, P2, P3, P4 in the internal combustion engine 10. The first position P1 is in a so-called main gallery that is an oil passage through which the lubricating oil supplied from the oil pump flows, and the second position P2 is in the vicinity of the outlet of the main gallery to the upper deck 50 side. is there. The third position P3 is in the vicinity of the opening on the upper deck 50 side in the return oil passage 51, and the fourth position P4 is in the oil pan.

  The lubricating oil staying on the upper deck 50 is cooled by each heat exchange member 70 provided on the upper deck 50. That is, since each of the heat exchange members 70 has a configuration in which the heat radiating portions 72A and the heat radiating portions 72B are alternately arranged, the contact area of the heat exchange member 70 with the lubricating oil on the upper deck 50 is widened. Thereby, the lubricating oil is efficiently cooled by the heat exchange member 70.

  A water jacket 65 is provided in the cylinder head 30 so as to pass near the shaft portion 61 of the bolt 60. Therefore, as compared with the case where the water jacket 65 is not provided, the temperature of the cylinder head 30 is lowered, and the temperature of the shaft portion 61 of the bolt 60 adjacent to the water jacket 65 via the partition wall 66 is also lowered. As a result, the temperature of the heat exchange member 70 to which the head portion 62 of the bolt 60 is pressed is also lowered. Thus, the lubricating oil is efficiently cooled on the upper deck 50 by the lubricating oil coming into contact with the upper deck 50 of the cylinder head 30, the head 62 of the bolt 60 and the heat exchange member 70 whose temperature has decreased.

  The lubricating oil thus cooled on the upper deck 50 is returned to the oil pan through the return oil passage 51. From the oil pan, lubricating oil is supplied to each lubricating part of the internal combustion engine 10 such as the intake valve drive mechanism 36 and the exhaust valve drive mechanism 39 by an oil pump. As a result, as is clear from FIG. 4, the temperature of the lubricating oil circulating in the internal combustion engine 10 becomes lower than when the heat exchange member 70 is not provided.

As described above, in the present embodiment, the following effects can be obtained.
(1) The heat exchange member 70 is provided on the upper deck 50 in a state where the heat exchange member 70 is fastened together with the cylinder head 30 by a bolt 60 for assembling the cylinder head 30 to the cylinder block 11. Therefore, the lubricating oil can be cooled through heat exchange between the heat exchanging member 70 and the lubricating oil staying on the upper deck 50. Further, since the heat exchange member 70 is attached to the cylinder head 30 by using the bolt 60 for assembling the cylinder head 30 to the cylinder block 11, a bolt for exclusive use may be provided separately, or a bolt for the bolt may be provided on the cylinder head 30. There is no need to create new holes. Therefore, the lubricating oil staying on the upper deck 50 can be cooled with a simple configuration without changing the shape of the cylinder head 30.

  (2) The periphery of the bolt 60 and the shaft portion 61 of the bolt 60 in the cylinder head 30 are cooled by the cooling water flowing through the water jacket 65. Here, since the distance between the water jacket 65 and the combustion chamber is longer than that provided between the combustion chamber 32 and the shaft portion 61 of the bolt 60, the cooling water flowing through the water jacket 65 is combusted. The chamber 32 is hardly affected by the combustion heat, and the temperature is maintained at a relatively low temperature. And since the axial part 61 of the volt | bolt 60 is cooled by such cooling water, the temperature rise of the heat exchange member 70 which contacts the volt | bolt 60 can be suppressed effectively, and the lubricating oil which retains on the upper deck 50 can be suppressed. Cooling efficiency can be improved.

  Further, since the interval between the combustion chamber 32 and the shaft portion 61 is narrow, even if the water jacket 65 is provided between the combustion chamber 32 and the shaft portion 61, the flow passage cross-sectional area becomes narrow, and the circulation amount of the cooling water Less. In contrast, in the present embodiment, the water jacket 65 is formed such that the shaft portion 61 of the bolt 60 is interposed between the water jacket 65 and the combustion chamber 32. Therefore, the passage cross-sectional area of the water jacket 65 can be widened, and the bolt 60 is efficiently cooled by the amount of circulation of the cooling water. Therefore, the temperature increase of the heat exchange member 70 that contacts the bolt 60 can be effectively suppressed, and the cooling efficiency of the lubricating oil staying on the upper deck 50 can be improved.

The embodiment may be changed to another embodiment as described below.
The heat exchange member 70 is made of a shape memory alloy plate material whose shape changes depending on the temperature between a state in which the back surface is in surface contact with the upper deck 50 and a state in which the back surface is separated from the upper deck 50. Also good. In this case, as shown in FIGS. 5A and 5B, when the temperature of the heat exchange member 70 is low, the back surface 72 a of the heat radiating portion 72 of the heat exchange member 70 is in surface contact with the upper deck 50. On the other hand, when the temperature of the heat exchange member 70 increases, the heat radiating portion 72 is deformed so that the tip 72b, which is the edge of the heat exchange member, is separated from the upper deck 50 based on the shape memory characteristics. As a result, a gap S is formed between the back surface 72a of the heat radiating portion 72 and the upper deck 50 so that the lubricating oil flows in, and the lubricating oil flows into the gap S. For this reason, the contact area of the heat exchange member 70 with the lubricating oil is increased, and the lubricating oil can be efficiently cooled.

  Further, when the temperature of the lubricating oil is low and the temperature of the heat exchange member 70 is also low, the back surface 72a of the heat radiating portion 72 of the heat exchange member 70 comes into surface contact with the upper deck 50 based on its shape memory characteristics. Therefore, the gap S as described above is not formed, and heat exchange between the back surface 72a of the heat radiating portion 72 and the lubricating oil is not performed. As a result, it is possible to suppress unnecessary cooling of the lubricating oil when the engine is cold.

  In addition, as shown in FIG. 6, an expansion / contraction portion 80 that expands at a high temperature but contracts at a low temperature may be provided between the heat radiating portion 72 of the heat exchange member 70 and the upper deck 50. Examples of such a stretchable part 80 include those provided with a thermo wax that expands in volume as the temperature rises. Even if comprised in this way, the effect | action and effect equivalent to other embodiment shown by Fig.5 (a) (b) can be acquired.

  As shown in FIG. 7, the heat exchange member 70 may be configured such that a part thereof is located outside the cylinder head 30. In this case, the cylinder head 30 is provided with a communication hole 85 communicating between the inside and the outside, and the heat exchange member 70 is inserted through the communication hole 85. If comprised in this way, the heat exchange member 70 can improve the cooling efficiency of lubricating oil by the part cooled by the air outside the cylinder head 30.

  As shown in FIG. 8, the heat exchange member 90 may be configured to be fixed to the cylinder head 30 by two or more bolts 60. In this case, it is preferable that a gap allowing the inflow of lubricating oil is interposed between the connecting portion 91 located between the adjacent bolts 60 and the upper deck 50. In this case, when the lubricating oil flows into the gap, the contact area between the heat exchange member 90 and the lubricating oil is increased, and further improvement in the cooling efficiency of the lubricating oil can be expected.

Further, the heat exchanging member 90 having the connecting portion 91 may have a configuration in which a heat radiating portion protruding from the connecting portion 91 is provided.
The heat exchange members 70 and 90 may be provided with protrusions and dimples. Even if comprised in this way, the contact area with the lubricating oil in the heat exchange members 70 and 90 can be widened. In addition, when the protrusions and the dimples are provided as described above, the strip-shaped heat radiation portion 72 (72A, 72B) may not be provided.

  DESCRIPTION OF SYMBOLS 10 ... Internal combustion engine, 11 ... Cylinder block, 30 ... Cylinder head, 32 ... Combustion chamber, 50 ... Upper deck, 60 ... Bolt, 61 ... Shaft part, 65 ... Water jacket, 70, 90 ... Heat exchange member, 72b ... Heat The tip of the heat dissipating part as the edge of the replacement member, 80 ... expansion and contraction part, S ... gap.

Claims (4)

In an internal combustion engine in which a cylinder head is assembled to a cylinder block with bolts,
An internal combustion engine characterized in that a heat exchange member that exchanges heat with lubricating oil staying on the upper deck of the cylinder head is fastened together with the cylinder head by the bolt.   The internal combustion engine according to claim 1, wherein a shaft portion of a bolt to which the heat exchange member is fastened is located between a water jacket and a combustion chamber of the cylinder head. The heat exchange member is configured by a shape memory alloy plate material whose shape changes depending on temperature between a state in which the back surface is in surface contact with the upper deck and a state in which the back surface is separated from the upper deck,
3. The internal combustion engine according to claim 1, wherein the edge of the heat exchange member is displaced in a direction away from the upper deck as the temperature of the heat exchange member becomes higher. The heat exchange member is constituted by a plate material,
Between the heat exchange member and the upper deck, an expansion / contraction part that extends as the temperature becomes higher is provided,
3. The internal combustion engine according to claim 1, wherein an edge portion of the heat exchange member is displaced in a direction away from the upper deck by extension of the expansion / contraction portion accompanying a rise in temperature of the lubricating oil.