JP3601417B2 - Cylinder block cooling structure - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a cooling structure for a cylinder block of an engine.
[0002]
[Prior art]
In the engine cylinder block, a water jacket is formed around the cylinder bore wall, in which engine cooling water is circulated to cool the cylinder bore wall heated from the combustion chamber.
In this case, the temperature of the cylinder bore wall is unlikely to be uniform. The reason for this is that, in the circumferential direction of each cylinder bore wall, the temperature of the portion in contact with the cylinder bores in which the flow speed is high and in contact with both sides in the direction becomes lower than the temperature of the portion corresponding to the space between the cylinder bores where the flow is settled. In the vertical direction of the cylinder bore wall, the temperature of the upper portion of the cylinder bore wall near the combustion chamber becomes higher than that of the lower portion. Further, in the cylinder bore arrangement direction, the temperature becomes higher toward the downstream side.
The non-uniform cylinder bore wall temperature causes problems such as deterioration of fuel efficiency and increase in unburned hydrocarbon (HC) emission. For example, if the cylinder bore wall temperature is different in the circumferential direction, the shape of the cylinder bore wall deviates from a circle, so that the followability of the piston ring and the oil ring to the inner surface of the bore wall is deteriorated, and the tension of the ring is increased to prevent it. Then, the friction at the time of sliding becomes large, and the fuel efficiency is deteriorated. Also, if the cylinder bore wall temperature is different in the vertical direction, in a direct injection gasoline engine or the like, the evaporation and combustion of the fuel attached to the middle part of the bore wall becomes worse, the fuel efficiency and torque are reduced, and unburned hydrocarbons ( HC) emissions also increase.
In order to suppress these problems, it is desired that the cylinder bore wall temperature be uniform. There have been various proposals to improve the water jacket with the cylinder block itself for the purpose of improving the wall temperature distribution, etc., but many have been difficult to mass-produce in terms of productivity, mold life, and strength. Therefore, a proposal has been made to improve the temperature distribution of the cylinder bore wall by disposing a spacer formed separately from the cylinder block (means for partially filling the space of the water jacket to make the bore wall temperature uniform) in the water jacket. (Eg, Japanese Utility Model Laid-Open No. 57-43338).
[0003]
[Problems to be solved by the invention]
However, the conventional cylinder block cooling structure disclosed in Japanese Utility Model Laid-Open No. 57-43338 has the following problems.
As shown in FIG. 15, when the cooling water inlet 12 (or outlet) is provided at the lower portion of the side of the cylinder block 11, the cooling water does not easily enter because the spacer 13 blocks the inlet 12. Even if the slit structure 14 is provided in the spacer 13 as shown in FIGS. 16 to 18, the water flow resistance is considerably large, and the driving efficiency of the water pump is reduced. In addition, the flow tends to be biased, and the uniform cooling property deteriorates.
Further, as shown in FIG. 19, for the cooling water inlet 12 which is above the cylinder block 11 and flows into the water jacket 15 from above, the distance from the inlet 12 to the spacer 13 is short due to the presence of the spacer 13. Therefore, the cooling water 16 is difficult to enter, the water flow resistance is considerably large, and the driving efficiency of the water pump is reduced. In addition, as shown in FIG. 20, a vortex 17 is formed immediately downstream of the inlet 12, and the flow is not smooth, so that the flow is likely to be biased and the uniform cooling property is deteriorated.
Also, regarding the cooling water outlet 18, as shown in FIGS. 21 and 22, the cooling water flowing on both sides of the cylinder bore row forms a confluence portion 20, where the flow collides and the stagnation portion 19 is formed. The water flow resistance is large because the flow is not smooth and the driving efficiency of the water pump is reduced. In addition, the manner in which stagnation occurs is not necessarily symmetrical, and the flow tends to be biased, resulting in poor uniform cooling.
An object of the present invention is to provide a cylinder block cooling structure capable of reducing water flow resistance and improving uniform cooling performance as compared with a conventional cylinder block cooling structure disclosed in Japanese Utility Model Laid-Open No. 57-43338. is there.
[0004]
[Means for Solving the Problems]
The present invention that achieves the above object is as follows.
(1) A spacer is formed in the water jacket of the cylinder block, which is formed separately from the cylinder block, for uniformizing the cylinder bore wall temperature, and the spacer covers the lower outer surface of the cylinder bore wall to allow cooling water to flow therethrough. the upper portion of the cylinder bore wall to a cooling structure of a cylinder block are cooled more strongly than the lower cooling stream flowing from above into the upper cooling water inlet portion is disposed to face the the spacer portion of the sheet cylinder block from a portion facing the water inlet along the cylinder bore wall outer surface is inclined or curved directing obliquely Me upward is formed, a cooling structure of a cylinder block said slope or curvature is formed in the spacer.
(2) A spacer is formed in the water jacket of the cylinder block, which is formed separately from the cylinder block, for uniformizing the cylinder bore wall temperature, and the spacer covers the lower outer surface of the cylinder bore wall to allow cooling water to flow therethrough. A cooling structure for a cylinder block that cools an upper portion of a cylinder bore wall more strongly than a lower portion, wherein the spacer has a weir disposed at a cooling water outlet of an upper part of the cylinder block, and has left and right side surfaces of the weir. The cooling structure for a cylinder block formed in the spacer is formed with a slope or a curve for changing the flow flowing on both sides of the cylinder bore obliquely upward or upward.
[0005]
In the cooling structure of the cylinder block of the above (1), the spacer portion disposed at the cooling water inlet portion of the cylinder block has a slope that obliquely directs the flow from the portion facing the cooling water inlet to the spacer along the outer surface of the cylinder bore wall. Alternatively, since the curved portion is formed , the flow resistance of the cooling water flowing into and out of the water jacket in the cylinder block is reduced, and the driving efficiency of the water pump is also increased. In addition, the flow of the cooling water into and out of the water jacket becomes smooth, stable, and has a good effect on uniform cooling.
Further, since the spacer is formed separately from the cylinder block, the degree of freedom and productivity of production is higher than when the spacer is formed integrally with the cylinder block.
Further, the inclination or curvature is given from the portion facing the cooling water inlet directed obliquely upward flow in the spacer along the cylinder bore wall outer surface, the flow resistance in the cooling water inlet of the cylinder block side is reduced It is smooth and has a good effect on uniform cooling.
The cooling structure of a cylinder block (2) above, the left and right side surfaces of the weir, the inclination or curvature changing the flow that has flowed both sides shea Rindaboa obliquely upward or upward is formed, the cooling water in the cylinder block upper The flow resistance at the outlet is reduced and smoothed, and a good effect on uniform cooling is provided.
[0006]
BEST MODE FOR CARRYING OUT THE INVENTION
A cooling structure for a cylinder block according to an embodiment of the present invention will be described with reference to FIGS. Components common or similar throughout all embodiments of the present invention are denoted by the same reference numerals throughout all embodiments of the present invention.
First, portions of the cooling structure of the cylinder block according to the present invention that are common or similar to the embodiments of the present invention will be described with reference to, for example, FIGS.
The cooling structure for a cylinder block according to the present invention is a cooling system for a cylinder block in which a spacer 5 for equalizing (or equalizing) the temperature of a wall 4 of a cylinder bore 3 is arranged in a water jacket 2 of a cylinder block 1. In the structure, spacer portions 5a and 5b arranged at the cooling water inlet portion 6 or the outlet portion 7 of the cylinder block are configured to reduce the flow resistance as compared with the conventional structure shown in FIGS. Cylinder block cooling structure.
[0007]
The engine cooling water from the water pump enters the water jacket 2 in the cylinder block from the cooling water inlet 6 and flows out from the cooling water inlet 7 to the water jacket in the cylinder head. The engine cooling water from the water pump may flow directly into the cylinder block 1 or may once enter the cylinder head and flow into the cylinder block 1 from the cylinder head. In the illustrated example, the case where the number of cylinders is three (one bank of a V-type six cylinder) is shown. However, it is needless to say that the number of cylinders may be other than three. Good. Although the cooling water inlet 6 is provided on the side of the cylinder block 1 in the illustrated example, the cooling water inlet 6 may be provided on the cylinder block 1.
[0008]
The spacers 5 partially fill the space in the water jacket 2 and adjust the area and strength of the cylinder bore wall 4 to be exposed to the cooling water so as to equalize the temperature of the wall 4 of the cylinder bore 3. For example, in the vertical direction, the temperature of the upper portion of the cylinder bore wall 4 rises due to heat from the combustion chamber, so that the cooling water selectively covers the upper surface of the cylinder bore wall 4 by covering the outer surface of the lower portion of the cylinder bore wall 4 with the spacer 5. Be sure to cool down strongly. Further, in the circumferential direction of the cylinder bore wall, a large amount of flow comes into contact with the portion between the cylinder bores and the flow velocity is increased, and the flow velocity is reduced on both sides in the cylinder bore arrangement direction.
[0009]
The spacer 5 is desirably formed separately from the cylinder block 1 and disposed in the water jacket 2. The reason for this is that by forming a separate body, the degree of freedom of the mold structure in the casting of the cylinder block is increased, the productivity is increased, and the deformation of the cylinder block outer wall when the cylinder head is fastened does not adversely affect the cylinder bore. And so on. However, the spacer 5 may be formed integrally with the cylinder block 1. The spacer 5 may be made of any material such as metal, resin, rubber, and sponge. However, from the viewpoint of preventing the deformation of the outer wall of the cylinder block from affecting the cylinder bore at the time of fastening the bolt to the cylinder head, when the external force is applied. It is desirable that the material itself can be deformed and absorbed.
[0010]
The operation of the common or similar parts throughout the embodiments of the present invention will be described.
Since the spacer portions 5a and 5b arranged at the cooling water inlet portion 6 or the outlet portion 7 of the cylinder block 1 have a structure in which the flow resistance is reduced as compared with the conventional structure shown in FIGS. The flow resistance of the flow into and out of the water jacket 2 in the cylinder block is reduced, the driving efficiency of the water pump is increased, and the fuel efficiency is improved. In addition, since the flow of the cooling water into and out of the water jacket 2 becomes smooth and stable, a good effect is exerted on the uniform cooling of the cylinder bore wall 4.
[0011]
Next, the configuration and operation unique to each embodiment of the present invention will be described.
In the cooling structure of the cylinder block according to the first to third embodiments of the present invention, as shown in FIGS. 1 to 5, the spacer portion 5 a is arranged at the cooling water inlet 6 on the side of the cylinder block 1. The structure for reducing the flow resistance has a structure in which the passage resistance does not increase as compared with the conventional structure shown in FIGS. More specifically, a structure that reduces the flow resistance,
{Circle around (1)} Example 1: The portion facing the cooling water inlet 6a is free of the spacer (FIG. 1).
{Circle over (2)} Embodiment 2: The portion facing the cooling water inlet 6a is made thinner in the spacer 5 than other portions (FIG. 2).
{Circle around (3)} Embodiment 3: A slope (slope) 8 or a curve is formed to direct the flow obliquely upward from the portion facing the cooling water inlet 6a along the outer surface of the cylinder bore wall 4 to the spacer 5 (FIGS. 3 to 5).
Any of the structures described above.
[0012]
As can be seen from the comparison with the conventional structure shown in FIGS. 15 to 18, in the structures of the first embodiment (FIG. 1) and the second embodiment (FIG. 2), the cross-sectional area of the passage is increased and the water flow resistance is reduced. In the structure of the third embodiment (FIGS. 3 to 5), the spacer 5 is provided with an inclination 8 or a curve to reduce the water flow resistance. Thereby, the resistance of the cooling water flowing into the water jacket 2 in the cylinder block is reduced, the driving efficiency of the water pump is increased, and the fuel efficiency is further improved. Further, since the flow of the cooling water into the water jacket 2 becomes smooth and stable, the flow is less likely to be deviated, and a good effect is exerted on the uniform cooling of the cylinder bore wall 4.
[0013]
In the cooling structure of the cylinder block according to the fourth to sixth embodiments of the present invention, as shown in FIGS. 6 to 10, the spacer portion 5 a is arranged at the cooling water inlet 6 above the cylinder block 1. And the structure for reducing the flow resistance,
{Circle around (1)} Embodiment 4: The portion facing the cooling water inlet 6a is free of the spacer (FIG. 7).
{Circle around (2)} Example 5: The spacer 5 is made thinner from the portion facing the cooling water inlet 6a along the outer surface of the cylinder bore wall 4 than the other portion (FIG. 8).
{Circle around (3)} Embodiment 6: A slope (slope) 9 or a curve is formed to direct the flow obliquely upward from the portion facing the cooling water inlet 6a to the spacer 5 along the outer surface of the cylinder bore wall 4 (FIGS. 9 and 10).
Any of the structures described above.
[0014]
As can be seen from the comparison with the conventional structure shown in FIGS. 19 and 20, in the structures of the fourth embodiment (FIG. 7) and the fifth embodiment (FIG. 8), the cross-sectional area of the passage is enlarged and the water flow resistance is reduced. In the structure of the sixth embodiment (FIGS. 9 to 10), the spacer 5 is provided with an inclination 9 or a curve to reduce the water flow resistance. Thereby, the resistance of the cooling water flowing into the water jacket 2 in the cylinder block is reduced, the driving efficiency of the water pump is increased, and the fuel efficiency is further improved. Further, since the flow of the cooling water into the water jacket 2 becomes smooth and stable, the flow is less likely to be deviated, and a good effect is exerted on the uniform cooling of the cylinder bore wall 4.
[0015]
In the cooling structure of the cylinder block according to the seventh and eighth embodiments of the present invention, as shown in FIGS. 11 to 14, a weir (spacer part 5 b) in which the spacer part 5 b is arranged at the cooling water outlet part 7 above the cylinder block 1. And the code is 5b). The structure for reducing the flow resistance is a structure having no confluent portion in the cooling fluid passage, or a structure having little stagnation even if there is. More specifically, the structure for reducing the flow resistance includes a slope 10 or a curve formed on both left and right sides of the weir 5b to change the flow flowing on both sides of the cylinder bore obliquely upward or upward.
The weir 5b may be formed separately from the cylinder block 1 or may be formed integrally. That is,
{Circle around (1)} Embodiment 7: Weir 5b is formed on spacer 5 formed separately from cylinder block 1 (FIGS. 11 and 12).
{Circle over (2)} Eighth Embodiment: The weir 5b is formed on the spacer 5 integrally formed with the cylinder block 1 (FIGS. 13 and 14).
Any of
However, if the weir 5b is formed integrally with the cylinder block 1, the casting mold structure becomes complicated, and the bore deformation due to the bolt fastening force at the time of fastening the cylinder head is deteriorated, so that the weir 5b is formed separately from the cylinder block 1. Is more desirable.
[0016]
As can be seen from comparison with the conventional structure shown in FIGS. 21 and 22, in the structures of the seventh embodiment (FIGS. 11 and 12) and the eighth embodiment (FIGS. 13 and 14), the weir 5b flows on both sides of the cylinder bore. It has a structure in which there is no confluence where the flows collide against each other. Further, the flow toward the outlet becomes smooth due to the inclination 10 or the curvature formed in the weir 5b. As a result, the resistance of the cooling water flowing out of the water jacket 2 in the cylinder block is reduced, the driving efficiency of the water pump is increased, and the fuel efficiency is improved. In addition, since the flow of the cooling water from the water jacket 2 becomes smooth and stable, the flow of the water jacket 2 in the cylinder block is less likely to be biased, and the uniform cooling property of the cylinder bore wall 4 is also advantageously provided.
[0017]
【The invention's effect】
According to the cooling structure of the cylinder block of the first aspect , the flow is directed obliquely upward from the portion facing the cooling water inlet to the spacer along the outer surface of the cylinder bore wall in the spacer portion arranged at the cooling water inlet portion of the cylinder block. Since the slope or curve is formed , the flow resistance of the cooling water flowing into and out of the water jacket in the cylinder block is reduced, and the driving efficiency of the water pump is also increased. In addition, the flow of the cooling water into and out of the water jacket becomes smooth, stable, and has a good effect on uniform cooling.
Further, since the spacer is formed separately from the cylinder block, the degree of freedom and productivity of production is higher than when the spacer is formed integrally with the cylinder block.
Further, the inclination or curvature is given from the portion facing the cooling water inlet directed obliquely upward flow in the spacer along the cylinder bore wall outer surface, the flow resistance in the cooling water inlet of the cylinder block side is reduced It is smooth and has a good effect on uniform cooling.
According to the cooling structure of a cylinder block according to claim 2, the left and right side surfaces of the weir, the inclination or curvature changing the flow that has flowed both sides shea Rindaboa obliquely upward or upward is formed, cooling of the cylinder block upper The flow resistance at the water outlet can be reduced and smooth, and uniform cooling can be promoted.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a cooling water inlet of a cylinder block cooling structure according to a first embodiment of the present invention and the vicinity thereof.
FIG. 2 is a cross-sectional view of a cooling water inlet of a cooling structure of a cylinder block according to a second embodiment of the present invention and the vicinity thereof;
FIG. 3 is a cross-sectional view of a cooling water inlet of a cylinder block cooling structure according to a third embodiment of the present invention and the vicinity thereof.
FIG. 4 is a plan view of a cylinder block cooling structure according to a third embodiment of the present invention.
FIG. 5 is a view as viewed from A in FIG. 4;
FIG. 6 is a plan view of a cylinder block cooling structure according to Embodiments 4, 5, and 6 of the present invention.
FIG. 7 is a cross-sectional view (including a cross section taken along line AA in FIG. 6) of a cooling structure of a cylinder block according to a fourth embodiment of the present invention.
FIG. 8 is a cross-sectional view (including a cross section taken along line AA of FIG. 6) of a cooling structure of a cylinder block according to a fifth embodiment of the present invention.
FIG. 9 is a cross-sectional view (including a cross-section taken along line AA of FIG. 6) of a cooling structure of a cylinder block according to Embodiment 6 of the present invention.
FIG. 10 is a sectional view of a cylinder block cooling structure according to a sixth embodiment of the present invention.
FIG. 11 is a plan view of a cylinder block cooling structure according to a seventh embodiment of the present invention.
FIG. 12 is a cross-sectional view (A view in FIG. 11) of a cooling structure of a cylinder block according to a seventh embodiment of the present invention.
FIG. 13 is a plan view of a cylinder block cooling structure according to an eighth embodiment of the present invention.
FIG. 14 is a sectional view (A view in FIG. 13) of a cooling structure of a cylinder block according to an eighth embodiment of the present invention.
FIG. 15 is a cross-sectional view of a conventional cooling structure of a cylinder block (Japanese Utility Model Application Laid-Open No. 57-43338; the same applies hereinafter) in the vicinity of a cooling water inlet on the side of the cylinder block.
FIG. 16 is a cross-sectional view of a conventional cooling structure for a cylinder block in the case where a slit is provided, showing a cooling water inlet portion and its vicinity.
FIG. 17 is a plan view of a conventional cylinder block cooling structure.
FIG. 18 is a cross-sectional view of a conventional cooling structure for a cylinder block (A view in FIG. 17).
FIG. 19 is a cross-sectional view of a conventional cooling structure for a cylinder block, showing a cooling water inlet at an upper portion of the cylinder block and its vicinity.
FIG. 20 is a cross-sectional view of a conventional cylinder block cooling structure in a longitudinal direction of a cylinder block including a cooling water inlet at an upper portion of the cylinder block.
FIG. 21 is a plan view including a cooling water outlet of a conventional cooling structure for a cylinder block.
FIG. 22 is a cross-sectional view of the conventional cooling structure of a cylinder block including a cooling water outlet (a view as viewed from A in FIG. 21).
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Cylinder block 2 Water jacket 3 Cylinder bore 4 Cylinder bore wall 5 Spacer 5a Spacer corresponding to cooling water inlet 5b Spacer corresponding to cooling water outlet 6 Cooling water inlet 7 Cooling water outlet 8, 9, 10 Inclined (or curved)

Claims (2)

In the water jacket of the cylinder block, a spacer formed separately from the cylinder block and for uniformizing the cylinder bore wall temperature is disposed. the upper a cooling structure of a cylinder block are cooled more strongly than the lower, the flow that has flowed from above into the upper cooling water inlet portion is disposed to face the the spacer portion of the sheet cylinder block cooling water inlet from the opposite part along the cylinder bore wall outer surface is inclined or curved directing obliquely Me upward is formed, a cooling structure of a cylinder block said slope or curvature is formed in the spacer. In the water jacket of the cylinder block, a spacer formed separately from the cylinder block and for uniformizing the cylinder bore wall temperature is disposed. A cooling structure for a cylinder block that cools an upper part more strongly than a lower part, wherein the spacer has a weir arranged at a cooling water outlet part on an upper part of the cylinder block, and a cylinder bore on both left and right side surfaces of the weir. The cooling structure of the cylinder block formed on the spacer is formed with a slope or a curve for changing the flow flowing through the spacer obliquely upward or upward.

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