JP2010150989A - Internal combustion engine cooling structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To uniformize cooling performance by respective inter-bore coolant passages formed between respective cylinder bores, in an internal combustion engine including banks wherein three or more cylinders are arranged in series. <P>SOLUTION: A difference of pressure loss is caused while a coolant flowing in a block side water jacket 6 and a head side water jacket flows along a cylinder arrangement and a pressure difference is caused in respective inter-cylinder-bore areas 12, 14, 16. The coolant flows from a side of the block side water jacket 6 to a side of the head side water jacket side via the inter-bore coolant passages 18, 20, 22 by this pressure difference. Although the pressure difference becomes larger toward a downstream side, a flow resistance of the inter-bore coolant passages 18-22 becomes larger toward the downstream side due to the difference of their respective diameters. Thus, coolant flow rates by the respective inter-bore coolant passages 18-22 become closer to one another or same. Hence, it is possible to equalize cooling performance by the respective inter-bore coolant passages 18-22. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  In the internal combustion engine having a bank in which three or more cylinders are arranged in series, the present invention provides a cylinder block side coolant passage and a cylinder head side coolant passage by means of an inter-bore coolant passage formed between the cylinder bores of the bank. The present invention relates to an internal combustion engine cooling structure that cools a region between cylinder bores of a cylinder block by circulating a coolant between them.

An internal combustion engine cooling structure that adjusts the amount of coolant flowing between cylinder bores of cylinders arranged in series in a bank is disclosed in order to prevent cooling loss and cylinder bore deformation caused by uneven cooling effects in the internal combustion engine. For example, see Patent Documents 1 and 2). In Patent Document 1, the amount of coolant flowing between cylinder bores is adjusted according to the combustion timing relationship between cylinders. In Patent Document 2, in particular, in order to ensure the roundness of the bore, the flow rate of the coolant flowing between all the cylinder bores is increased to enhance the cooling effect between all the cylinder bores.
Japanese Patent Laying-Open No. 2007-247523 (page 5-6, FIG. 2-4) Japanese Patent Laying-Open No. 2005-325712 (page 4-5, FIG. 3-4)

  However, originally, in an internal combustion engine in which a sufficient coolant flow rate can be obtained, the relationship between the combustion timing and the coolant flow rate in the cylinder can be improved without forming a coolant passage as in Patent Documents 1 and 2. Even if not, there is no problem in the cooling between the cylinder bores.

  However, even in such an internal combustion engine in which a sufficient coolant flow rate can be obtained, when three or more cylinders are arranged in the bank and two or more cylinder bore areas exist in the cylinder block, each cylinder bore area Difference in cooling performance occurs. For this reason, the cooling state between cylinders varies, and variations in bore shapes occur. Accordingly, an excessive performance requirement for the coolant pump and an excessive tension requirement for the piston ring are executed, which adversely affects the performance of the internal combustion engine such as fuel efficiency.

  An object of the present invention is to equalize the cooling performance by the inter-bore coolant passage formed between the cylinder bores in an internal combustion engine having a bank in which three or more cylinders are arranged in series.

In the following, means for achieving the above-mentioned purpose, and its operation and effect are described.
The internal combustion engine cooling structure according to claim 1 is an internal combustion engine having a bank in which three or more cylinders are arranged in series, and a cylinder block side coolant passage is formed by an interbore coolant passage formed between the cylinder bores of the bank. An internal combustion engine cooling structure that cools a region between cylinder bores of a cylinder block by flowing a coolant between the cylinder head side coolant passages, and the flow resistance of the interbore coolant passage is between each cylinder bore. Is set according to a pressure difference between the cylinder block side coolant passage and the cylinder head side coolant passage.

  Since the cylinder block side coolant passage and the cylinder head side coolant passage have different flow path shapes and sizes, the coolant introduced into the internal combustion engine flows through the respective cooling station passages along the bank cylinder arrangement. Even in the position between the same cylinder bores, there is a difference in pressure loss. Due to this difference in pressure loss, a pressure difference is generated between the coolant flowing in one cylinder block side coolant passage and the coolant flowing in the other cylinder head side coolant passage, and this pressure difference forms between the cylinder bores. The coolant flows through the coolant passage between the bores.

  When the flow resistance of the inter-bore coolant passage is set regardless of the pressure difference between the cylinder block-side coolant passage and the cylinder head-side coolant passage, for example, all the inter-bore coolant passages are the same. When the flow resistance is set, the difference in pressure difference between the cylinder bores is directly reflected in the flow of the cooling liquid, and the flow rate of the cooling liquid is changed for each of the cooling liquid passages between the bores.

  In the present invention, the flow resistance of the interbore coolant passage is set according to the pressure difference between the cylinder block side coolant passage and the cylinder head side coolant passage between the cylinder bores. For this reason, the difference in the pressure difference is directly reflected in the flow of the coolant, so that the coolant flow rate can be countered, and the coolant flow rate can be made closer or the same. As a result, the cooling performance by the coolant passages between the bores can be made uniform.

  3. The internal combustion engine cooling structure according to claim 2, wherein in the internal combustion engine cooling structure according to claim 1, the cylinder block side coolant passage and the cylinder head immediately after the coolant is introduced into the internal combustion engine from one place. The flow is divided into the side coolant passage.

  In this way, the coolant may be divided immediately after being introduced into the internal combustion engine, and flow into the cylinder block side coolant passage and the cylinder head side coolant passage, respectively. As a result, even if the pressure is the same at the position of the branch flow, while flowing through the cylinder block side coolant passage and the cylinder head side coolant passage, the difference between the pressure losses in the respective coolant passages causes a difference between the same cylinder bores. Even if it reaches, a pressure difference occurs.

  Due to this pressure difference, the coolant flows in the bore-bore coolant passage that communicates between the cylinder block-side coolant passage and the cylinder head-side coolant passage. Not identical between cylinder bores due to pressure loss differences. Accordingly, the flow resistance of the coolant passage between the bores is set in accordance with the pressure difference between the cylinder block side coolant passage and the cylinder head side coolant passage between the cylinder bores, thereby bringing the coolant flow rate closer. In other words, the cooling performance by the coolant passages between the bores can be made uniform.

The internal combustion engine cooling structure according to claim 3 is the internal combustion engine cooling structure according to claim 2, wherein a coolant is introduced from one end side of the arrangement of the cylinders.
As a result, the pressure difference between the cylinder block side coolant passage and the cylinder head side coolant passage between the cylinder bores on the downstream side tends to be larger than between the cylinder bores on the upstream side of the array. For this reason, the flow resistance of the coolant passage between the bores is set according to the pressure difference between the cylinder block side coolant passage and the cylinder head side coolant passage between the cylinder bores. Even if it is enlarged, the coolant flow rate can be made closer or the same. As a result, the cooling performance by the coolant passages between the bores can be made uniform.

  The internal combustion engine cooling structure according to claim 4 is the internal combustion engine cooling structure according to claim 2 or 3, wherein the cylinder block side coolant is introduced into the internal combustion engine from an inlet provided on the cylinder block side. The flow is divided into a passage and the cylinder head side coolant passage.

  More specifically, a coolant introduction port is provided on the cylinder block side in the internal combustion engine, and after introducing the coolant into the internal combustion engine from this introduction port, the cylinder block side coolant passage and the cylinder head side coolant are introduced. It is good also as a structure branched to a channel | path. The coolant is initially introduced into the cylinder block side coolant passage on the cylinder block side, and the coolant flows relatively smoothly in the cylinder block side coolant passage. However, the coolant flow branched from the cylinder block side coolant passage to the cylinder head side coolant passage has a relatively large flow resistance and a large pressure loss. The pressure difference from the block side coolant passage increases.

  However, the flow resistance of the coolant passage between the bores is set according to the pressure difference, so that the coolant flow rate in each of the coolant passages between the bores can be made closer or the same, The cooling performance in the area between the cylinder bores can be made uniform.

  The internal combustion engine cooling structure according to claim 5, wherein the interbore coolant passage is inclined with respect to the bore axial direction between the cylinder bores. It is characterized by being provided across the center of the area between the cylinder bores.

  By forming the inter-bore coolant passage having different flow resistances in such an inclined state, even if there is only one inter-bore coolant passage between the cylinder bores, the region between the cylinder bores can be effectively Can be cooled.

  The internal combustion engine cooling structure according to claim 6, wherein the interbore coolant passage includes the cylinder block side coolant passage and the cylinder head, according to any one of claims 1 to 5. The flow resistance is set higher toward the downstream side in the side coolant passage.

  The pressure difference between the coolant passages tends to increase toward the downstream side of the cylinder block side coolant passage and the cylinder head side coolant passage. From this, by increasing the flow resistance of the coolant passage between the bores toward the downstream side, the coolant flow rate in the coolant passage between the bores can be made closer or the same, and between the cylinder bores. The cooling performance in the region can be made uniform.

  In the internal combustion engine cooling structure according to claim 7, in the internal combustion engine cooling structure according to any one of claims 1 to 6, the flow resistance of the inter-bore coolant passage is equal to one in the inter-bore coolant passage. It is characterized by being adjusted by the size of the part or the whole diameter.

Thus, the flow resistance of the coolant passage between the bores can be easily adjusted by the size of the diameter.
The internal combustion engine cooling structure according to claim 8, wherein the flow resistance of the interbore coolant passage is a penetration in a gasket disposed between the cylinder block and the cylinder head. It is characterized by being adjusted by the size of the hole diameter.

  In this way, the flow resistance of the coolant passage between the bores may be adjusted depending on the diameter of the through hole of the gasket forming a part of the coolant passage between the bores, and it is easy to change only the through hole of the gasket. The magnitude of the flow resistance of the coolant passage between the bores can be adjusted.

  In the internal combustion engine cooling structure according to claim 9, in the internal combustion engine cooling structure according to claim 7, the flow resistance of the inter-bore coolant passage is determined by the opening hole on the cylinder head side in the inter-bore coolant passage. It is characterized by being adjusted according to the size of the diameter.

  Thus, the flow resistance of the coolant passage between the bores may be adjusted depending on the size of the opening hole on the cylinder head side that forms a part of the coolant passage between the bores, and only the opening diameter on the cylinder head side is changed. Thus, it is possible to easily adjust the flow resistance of the coolant passage between the bores.

[Embodiment 1]
1 to 4 show an internal combustion engine 2 to which the internal combustion engine cooling structure described above is applied, and particularly shows the configuration of the cylinder block 4 as a center. 1 is a perspective view of the internal combustion engine 2, FIG. 2 is a plan view of the cylinder block 4, FIG. 3 is a cross-sectional view of the internal combustion engine 2 along the line AA in FIG. 2, and FIG. It is a perspective view. It should be noted that the outer peripheral shape of the internal combustion engine 2 is shown in a schematic shape.

  The internal combustion engine 2 is a four-cylinder internal combustion engine comprising one bank of cylinder blocks 4 and four banks (# 1, # 2, # 3, # 4) arranged in series in this one bank. Accordingly, four cylinder bores 4a to 4d are provided in the cylinder block 4 in series. In the cylinder block 4, a block-side water jacket 6 is formed around the cylinder bores 4 a to 4 d as a cylinder block-side coolant passage, and the cylinder block 4 is cooled from an introduction port 8 provided on the # 1 cylinder side. Liquid (here, cooling water) is introduced into the block-side water jacket 6.

  A part of the coolant introduced into the block-side water jacket 6 flows through the block-side water jacket 6 to the # 4 cylinder along the arrangement of the cylinder bores 4a to 4d. As indicated by the arrow T, the head-side water jacket 11 that rises from the opening formed in the gasket 9 (FIG. 3) and the cylinder head 10 toward the cylinder head 10 and is the cylinder head-side coolant passage. After flowing into (FIG. 3), it is discharged to the radiator side.

  Further, another part of the coolant immediately after being introduced into the block-side water jacket 6 from the introduction port 8, as indicated by the arrow S, is opened from the opening formed in the gasket 9 and the cylinder head 10. Ascend to the 10 side and flow into the head side water jacket 11. Then, it flows in the head-side water jacket 11 and is discharged to the radiator side together with the coolant rising as indicated by the arrow T on the # 4 cylinder side described above. Such a coolant flow is generated by driving the water pump.

  Between the four cylinder bores 4a to 4d arranged in series, there are three inter-cylinder bore regions 12, 14, and 16. The inter-cylinder bore regions 12 to 16 are regions sandwiched between two adjacent cylinder bores 4a to 4d, and are easily provided with high temperatures. Therefore, inter-bore coolant passages 18, 20, and 22 are provided, respectively.

  These inter-bore coolant passages 18, 20, and 22 are respectively provided at positions between the two cylinder bores 4a to 4d so as to be inclined with respect to the bore axial direction and across the centers of the regions 12 to 16 between the cylinder bores. It has been. As a result, the interbore coolant passages 18, 20, and 22 connect the block-side water jacket 6 and the head-side water jacket 11.

  Here, among the coolant introduced from the inlet 8, the coolant flowing in the block-side water jacket 6 from the # 1 cylinder to the # 4 cylinder smoothly flows with a relatively small flow resistance. The pressure loss that occurs during the flow until is small, and the slope of the pressure drop is relatively small as shown in the graph of FIG.

  On the other hand, since the coolant introduced into the head-side water jacket 11 immediately after being introduced into the block-side water jacket 6 from the introduction port 8 has a relatively large flow resistance, the head-side water jacket 11 has # 4. The pressure loss generated during the flow to the cylinder is large, and the gradient of the pressure drop is relatively large as shown in FIG. Therefore, there is a difference in the coolant pressure between the block-side water jacket 6 side and the head-side water jacket 11 side between the upstream side and the downstream side in the cylinder arrangement. Further, the pressure differences dP1, dP2, and dP3 are not the same, and the pressure differences dP1 to dP3 increase as the pressure difference moves from the # 1 cylinder position to the # 4 cylinder position. The pressure differences dP1, dP2, and dP3 indicate pressure differences at the positions between the cylinder bores.

  The flow resistances of the inter-bore coolant passages 18 to 22 are adjusted according to the pressure differences dP1 to dP3. Specifically, the diameters D1, D2, and D3 of the interbore coolant passages 18, 20, and 22 are made smaller toward the downstream side as shown in FIG. 5 (D1> D2> D3). This increases the flow resistance of the inter-bore coolant passages 18 to 22 as the pressure differences dP1 to dP3 increase toward the downstream. As a result, the amount of the coolant flowing from the block-side water jacket 6 to the head-side water jacket 11 via the three inter-bore coolant passages 18 to 22 is brought close to the same state or completely the same, so that the regions 12 between the cylinder bores. The cooling performance in ~ 16 is made uniform.

  Incidentally, the through hole 9a of the gasket 9 and the opening hole 10a of the cylinder head 10 which are arranged on the deck surface 24 of the cylinder block 4 which is a part of the interbore coolant passages 18 to 22 shown in FIG. The diameters D1, D2, and D3 of the side bore cooling fluid passages 18 to 22 are formed to have the same diameter, a larger diameter, or a slightly smaller diameter.

According to the first embodiment described above, the following effects can be obtained.
(I). The block-side water jacket 6 and the head-side water jacket 11, which are cylinder block-side coolant passages, have different flow path shapes, and pressure loss occurs while the coolant introduced into the internal combustion engine 2 flows along the cylinder arrangement of the banks. As shown in FIG. 5, pressure differences dP1 to dP3 are generated between the cylinder bores. Due to the pressure differences dP1 to dP3, the coolant flows from the block side water jacket 6 side to the head side water jacket 11 side via the interbore coolant passages 18 to 22.

  Although the pressure differences dP1 to dP3 are larger toward the downstream side, the flow resistance of the inter-bore coolant passages 18 to 22 is increased according to the increase in the pressure differences dP1 to dP3 toward the downstream side due to the difference in the diameters D1 to D3. Has increased. This counteracts the change in the coolant flow rate due to the difference in pressure difference dP1 to dP3 between the positions between the cylinder bores, so that the coolant flow rate is made close to or the same.

  In this way, the cooling performance by the interbore coolant passages 18 to 22 can be made uniform. Accordingly, it is possible to prevent the cooling state from varying between the cylinders # 1 to # 4 and the variations in the shapes of the cylinder bores 4a to 4d, and the excessive performance requirement for the coolant pump (here, the water pump) and the excessive tension for the piston ring. It is possible to prevent the deterioration of the internal combustion engine performance such as the deterioration of the fuel consumption performance due to the demand.

  (B). In particular, since the coolant is introduced from one end of the cylinder arrangement in which four cylinders are arranged in series, the pressure difference dP1 at the position between the cylinder bores on the most upstream side and the pressure difference dP3 at the position between the cylinder bores on the most downstream side are Although a large divergence occurs, it is possible to easily make the coolant flow rate the same or close by the diameters D1 to D3 of the coolant passages 18 to 22 between the bores. This makes it possible to equalize the cooling performance of the inter-bore coolant passages 18-22.

  (C). The inter-bore coolant passages 18 to 22 having different diameters D1 to D3 are located between the block-side water jacket 6 and the head-side water jacket 11 in the state between the cylinder bores 12 to 16 in an inclined state with respect to the bore axial direction as described above. It is provided across the center. Thereby, even if the number of the inter-bore coolant passages 18 to 22 is one at the position between the cylinder bores, the areas 12 to 16 between the cylinder bores can be effectively cooled.

[Embodiment 2]
In the first embodiment, the flow resistance is adjusted by providing a difference in the diameters D1 to D3 of the inter-bore coolant passages 18 to 22 in the portions between the cylinder bore regions 12 to 16. For example, FIG. It may be as shown in. That is, the diameter Dx of the inter-bore coolant passage 118 in the region between the cylinder bores is the same in all the inter-bore coolant passages, and the inter-bore cooling is provided by providing a difference in the diameter of the through hole 109a of the gasket 109 on the outlet side. The flow resistance in the entire liquid passage 118 may be adjusted for each inter-bore coolant passage 118.

  As shown in FIG. 6B, the opening formed in the cylinder head 210 that discharges the coolant to the head-side water jacket 211 without making a difference between the diameter Dx and the diameter of the through hole 209a of the gasket 209. By providing a difference in the diameter of 210a, the flow resistance in the entire interbore coolant passage 218 may be adjusted for each interbore coolant passage 218.

[Other embodiments]
(A). In each of the above embodiments, an example of an in-line four-cylinder internal combustion engine has been described. However, the present invention can also be applied to an internal combustion engine in which three or more cylinders are in series, such as an in-line six cylinder.

Furthermore, even when there are a plurality of banks such as a V-type internal combustion engine, the present invention can be applied to each bank if the internal combustion engine has three or more cylinders in series in each bank.
(B). In each of the above-described embodiments, as shown in FIG. 5, the head-side water jacket 11 has a larger pressure drop gradient in the coolant flow than the block-side water jacket 6. Depending on the shape, on the contrary, the block-side water jacket may have a larger pressure drop gradient of the coolant than the head-side water jacket. In this case, the flow of the coolant in the interbore coolant passage is in the opposite direction, but the present invention can be similarly applied.

  (C). In the first embodiment, the coolant passage between the bores in the region between the cylinder bores is partially enlarged on the outlet side, but the entire region of the coolant passage between the bores in the region between the cylinder bores has a constant diameter. A difference may be provided in the flow resistance between the coolant passages between the bores by providing a difference.

  Furthermore, by setting the whole area of the coolant passage between the bores in the region between the cylinder bores to a constant diameter, and reducing the diameter of only a part of the coolant passage between the bores, and providing a difference in the diameter of this part, A difference may be provided in the flow resistance.

1 is a perspective view of an internal combustion engine according to a first embodiment. FIG. 3 is a plan view of a cylinder block according to the first embodiment. Sectional drawing of the internal combustion engine in the AA line in FIG. FIG. 3 is a partially broken perspective view of the cylinder block according to the first embodiment. 6 is a graph showing the relationship between the flow position and the coolant pressure on the cylinder block side and the cylinder head side in Embodiment 1, and the relationship between the flow position and the diameter of the coolant passage between each bore. Flow resistance adjustment structure explanatory drawing in Embodiment 2. FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 2 ... Internal combustion engine, 4 ... Cylinder block, 4a-4d ... Cylinder bore, 6 ... Block side water jacket, 8 ... Introduction port, 9 ... Gasket, 9a ... Through-hole, 10 ... Cylinder head, 10a ... Opening hole, 11 ... Head Side water jacket, 12, 14, 16 ... area between cylinder bores, 18, 20, 22 ... inter-bore coolant passage, 24 ... deck surface, 109 ... gasket, 109a ... through hole, 118 ... inter-bore coolant passage, 209 ... Gasket, 209a ... through hole, 210 ... cylinder head, 210a ... open hole, 211 ... head side water jacket, 218 ... bore coolant passage.

Claims (9)

In an internal combustion engine having a bank in which three or more cylinders are arranged in series, a coolant is provided between the cylinder block side coolant passage and the cylinder head side coolant passage by an interbore coolant passage formed between the cylinder bores of the bank. Is an internal combustion engine cooling structure that cools the area between the cylinder bores of the cylinder block by circulating
The flow resistance of the inter-bore coolant passage is set according to the pressure difference between the cylinder block side coolant passage and the cylinder head side coolant passage between the cylinder bores. Engine cooling structure. 2. The internal combustion engine cooling structure according to claim 1, wherein the coolant is divided into the cylinder block side coolant passage and the cylinder head side coolant passage immediately after being introduced into the internal combustion engine from one place. An internal combustion engine cooling structure. 3. The internal combustion engine cooling structure according to claim 2, wherein a coolant is introduced from one end side of the arrangement of the cylinders. 4. The internal combustion engine cooling structure according to claim 2, wherein after being introduced into the internal combustion engine from an inlet provided on the cylinder block side, the flow is divided into the cylinder block side coolant passage and the cylinder head side coolant passage. An internal combustion engine cooling structure. 5. The internal combustion engine cooling structure according to claim 1, wherein the inter-bore coolant passage is provided across the center of the region between the cylinder bores in an inclined state with respect to the bore axial direction between the cylinder bores. An internal combustion engine cooling structure characterized in that 6. The internal combustion engine cooling structure according to claim 1, wherein the interbore coolant passage has a higher flow resistance toward a downstream side of the cylinder block side coolant passage and the cylinder head side coolant passage. An internal combustion engine cooling structure characterized by being set. The internal combustion engine cooling structure according to any one of claims 1 to 6, wherein a flow resistance of the inter-bore coolant passage is adjusted by a size of a part or all of the diameter of the inter-bore coolant passage. An internal combustion engine cooling structure. 8. The internal combustion engine cooling structure according to claim 7, wherein the flow resistance of the interbore coolant passage is adjusted by the size of a through hole in a gasket disposed between the cylinder block and the cylinder head. An internal combustion engine cooling structure. 8. The internal combustion engine cooling structure according to claim 7, wherein a flow resistance of the inter-bore coolant passage is adjusted by a size of an opening hole on a cylinder head side in the inter-bore coolant passage. An internal combustion engine cooling structure.

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