JP2002180831A - Cooling system and cylinder block for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cooling system and a cylinder block for an internal combustion engine capable of reducing a warming time, of reducing friction between each cylinder bore and a piston and of improving fuel consumption. SOLUTION: In this cooling system 11, cooling water delivered from a radiator 12 to a cylinder block 14 by a water pump 15 is fed to respective water jackets 16 and 18 of a block body 17 and a cylinder head 19 and returned to the radiator. The total amount of the cooling water delivered to the cylinder block 14 is run to the water jacket 18 of the cylinder head 19, part of the cooling water flowing through the inside of the jacket 18 flows into the water jacket 16 of the block body through water passages 21-23 between the bores of the block body 17. The cooling water warmed by receiving heat while flowing inside the water jacket 18 flows into the water jacket of the block body through the water passages between bores.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling system for an internal combustion engine mounted on a vehicle such as an automobile and a cylinder block of the internal combustion engine to which the cooling system is applied. The present invention relates to a cooling system and a cylinder block for an internal combustion engine, which are devised in a flow manner.

[0002]

2. Description of the Related Art FIG. 8 shows a cooling system and a cylinder block of a conventional internal combustion engine. The cylinder block 72 of the engine 71 includes a block body 73 and a cylinder head 74.
Consists of The block body 73 has a water jacket 75 formed around a plurality of cylinder bores (not shown), and the cylinder head 74 has a water jacket 76 for cooling the combustion chamber of each cylinder. The outlet side water passage 77 of the water jacket 75 communicates with the inlet side water passage 78 of the water jacket 76. In addition, between the plurality of cylinder bores of the block body 73, the water passages 79, 80,
81 are provided.

The cooling system 82 of the internal combustion engine shown in FIG.
Then, the entire amount of the cooling water sent by the water pump 83 flows into the water jacket 75 of the block body 73. The cooling water that has flowed into the jacket 75 flows into the water jacket 76 through the inter-bore water passages 79, 80, and 81, and also flows into the water jacket 76 through the outlet water passage 77 and the inlet water passage 78. The cooling water thus flowing into the water jacket 76 through the two paths flows through the jacket 76 and then flows out of the cylinder head 74. This spilled cooling water
The water is sent to the radiator 85 through the pipe 84 and is cooled by heat exchange with the outside air. The cooled cooling water is sent from the radiator 85 through the pipe 86 to the water jacket 75 by the water pump 83.

[0004]

However, the above prior art has the following problems. (1) The entire amount of the cooling water sent by the water pump 83 flows into the water jacket 75 of the block body 73, flows through the jacket 75, and then flows into the water jacket 76 through the two paths. It has become. With such a configuration, the cooling water cooled by the radiator 85 first flows through the water jacket 75 of the block main body 73 and cools the periphery of each cylinder bore, so that it takes time to increase the wall temperature around each cylinder bore. The warm-up time becomes longer.

(2) Since the warm-up time is prolonged, the viscosity of the engine oil decreases when the engine is started, and it takes time for the friction between each cylinder bore and the piston ring to decrease, resulting in deterioration of fuel efficiency. Resulting in.

(3) Regarding the temperature distribution of the wall temperature around each cylinder bore (temperature distribution around the wall around each cylinder bore)
Consider this with reference to FIG. In the figure, reference numeral 90 indicates one of the cylinder bores of the block body 73, and reference numeral 91
Shows the temperature distribution of the wall temperature around the cylinder bore 90. In this temperature distribution, the temperature (° C.) is represented by a horizontal axis X and a vertical axis Y with the center of the cylinder bore 90 as the origin (0 ° C.). Further, in the same figure, reference numerals A and B indicate portions between the bores of the bore wall portion, respectively. For example, in the case of a horizontally mounted multi-cylinder engine, if the portion A is a portion between the bores on the thrust side of the bore wall, the portion B is a portion between the bores on the anti-thrust side of the bore wall. In addition, symbols C and D in FIG.
These are the front part and the rear part of the bore wall, respectively. In the above-described conventional technique, the temperature distribution 91 shown by a broken line in FIG.
As is clear from the above, since a larger flow rate of cooling water flows through the portions C and D of the bore wall portion than the portions A and B,
The temperatures of the parts C and D are lower than those of the parts A and B. As described above, in the above-described related art, the temperature distribution of the wall temperature around each cylinder bore, that is, the temperature distribution in the circumferential direction of each cylinder bore 90 is not uniform. Therefore, at the time of actual operation, each cylinder bore 90 which is a perfect circle is deformed, and each cylinder bore 90 is deformed.
Friction between the piston ring and the piston ring increases. This also deteriorates fuel efficiency at the time of starting the engine and the like.

[0007] The present invention has been made in view of such circumstances, and aims to shorten the warm-up time, reduce the friction between each cylinder bore and the piston ring,
Another object of the present invention is to provide a cooling system and a cylinder block for an internal combustion engine that improve fuel efficiency.

[0008]

The means for solving the above problems and the operation and effects thereof will be described below. The invention according to claim 1 cools each part of the cylinder block by flowing cooling water sent from a radiator to a cylinder block of an internal combustion engine by a water pump to each water jacket of a block body and a cylinder head constituting the cylinder block. Then, in the cooling system of the internal combustion engine in which the cooling water after the cooling is returned from the cylinder block to the radiator, the entire amount of the cooling water sent to the cylinder block by the water pump flows into the water jacket of the cylinder head. A part of the cooling water flowing in the water jacket is caused to flow into the water jacket of the block main body through a water passage between bores provided between the cylinder bores of the block main body. It is a cooling system.

According to a second aspect of the present invention, there is provided a block body having a water jacket formed around a plurality of cylinder bores, and a cylinder head having a water jacket therein and fastened to the block body. The cylinder block of the internal combustion engine having a bore-to-bore water passage communicating between the water jackets between the cylinder bores, in which the cooling water sent from the water pump flows in the water jackets, the total amount of the cooling water sent by the water pump. However, while flowing into the water jacket of the cylinder head and flowing through the water jacket, a part of the cooling water flowing into the water jacket flows into the water jacket of the block main body through the water passage between the bores. Of an internal combustion engine characterized in that Is Linda block.

According to the first and second aspects of the invention, the entire amount of the cooling water sent by the water pump flows into the water jacket of the cylinder head, and a part of the flowing cooling water flows between the bores between the cylinder bores. Through the water jacket of the block body. Thus, the cooling water receives heat while flowing through the water jacket of the cylinder head and warms, and the warmed cooling water flows into the water jacket of the block body through the water passage between the bores. For this reason, the temperature rise of the wall around each cylinder bore is promoted, and the warm-up time can be reduced.

A part of the cooling water flowing into the water jacket of the cylinder head flows into the water jacket of the block main body through the water passage between the bores of the cylinders. For this reason, of the wall around each cylinder bore,
Cooling water flows only between the cylinder bores where the temperature is highest. On the other hand, in the water jacket around the portion other than between the cylinder bores in the wall around each cylinder bore, the cooling water hardly flows, and the cooling water is in a stagnant state.

For this reason, between the cylinder bores, which become the highest in temperature, around the cylinder bores is sufficiently cooled by the cooling water, while the parts other than the parts between the cylinder bores are not cooled as much as between the cylinder bores. Therefore, the temperature distribution of the wall around each cylinder bore becomes uniform, and the roundness of each cylinder bore during operation is improved. At the same time, the temperature of the entire wall around each cylinder bore becomes higher than before, so that the viscosity of the engine oil decreases early. In this way, the roundness of each cylinder bore at the time of actual operation is improved, and the viscosity of the engine oil is reduced at an early stage. Fuel efficiency can be improved.

According to a third aspect of the present invention, in the cylinder block of the internal combustion engine according to the second aspect, the cooling water flowing in the water jacket of the block body is caused to flow out from the block body side to the outside. It is characterized by:

According to the present invention, the cooling water flowing in the water jacket of the block main body is caused to flow out from the block main body side, so that the sub flow path (piping) is connected to the water outlet of the block main body. Just do it. For this reason, it is not necessary to provide a water passage for connecting the two water jackets on the water outlet side, and the configuration of the block body and the cylinder head is simplified by that much, and the cost can be reduced.

According to a fourth aspect of the present invention, in the cylinder block of the internal combustion engine according to the second or third aspect, the cooling water flowing in the water jacket of the block body is returned to the water jacket of the cylinder head to return the cylinder water. It is characterized in that it is configured to flow out from the head side to the outside.

According to the present invention, the cooling water flowing through the water jacket of the block body is returned to the water jacket of the cylinder head and flows out from the cylinder head side to the outside, so that one water outlet is provided on the cylinder block side. I just need. Therefore, only one flow path (pipe) needs to be connected to the water outlet, and the cost can be further reduced.

According to a fifth aspect of the present invention, in the cylinder block of the internal combustion engine according to any one of the second to fourth aspects, the plurality of cylinder bores are each constituted by a cylinder liner, and a lower portion of each cylinder liner is a block. Each cylinder liner is press-fitted into each cylinder of the main body, and a water jacket is formed between an upper outer peripheral surface of each cylinder liner and an inner wall surface of an outer wall of the block main body, thereby forming an upper portion of each cylinder liner into a wet structure. .

According to the present invention, since the cylinder liner is of a press-fitting type having an interference, there is no water leakage at the water jacket portion. Since the cylinder liner is a press-fit type,
The thickness of the liner becomes uniform, the residual stress is small, and the bore deformation (deformation of the cylinder liner) is small as compared with the cast-in liner. Thereby, the tension and the friction are further reduced, and the fuel efficiency can be further improved.

According to a sixth aspect of the present invention, in the cylinder block of the internal combustion engine according to any one of the second to fifth aspects, a portion between the cylinder bores of each of the cylinder liners is provided.
A straight mating surface is formed, the mating surfaces of the cylinder liners are abutted against each other, and the upper portion thereof is joined. Below the joint portion, the lower liner wall portion is depressed to form a water passage between bores. Is formed.

According to the present invention, the rigidity of each cylinder liner can be improved, and an inter-bore water passage can be formed between the cylinder bores of each cylinder liner even when the size between the bores is small.

According to a seventh aspect of the present invention, in the cylinder block of the internal combustion engine according to the sixth aspect, the water jacket on the cylinder head side, which is fastened to the block body, is connected to the joint of each of the cylinder liners. It is characterized in that at least one communication hole between the bores for communicating the water channel is provided.

According to the present invention, since the communication hole between the bores is provided, the flow rate and the flow velocity of the cooling water for cooling the space between the bores of the respective cylinder liners can be sufficiently ensured. The distribution becomes more uniform. Therefore, deformation of each cylinder bore (deformation of each cylinder liner)
And the fuel efficiency is further reduced.

According to an eighth aspect of the present invention, in the cylinder block of the internal combustion engine according to any one of the fifth to seventh aspects, an upper outer peripheral surface of each of the cylinder liners and an inner wall surface of an outer wall of the block body are provided. The water jacket formed therebetween is characterized in that it has a V-shaped vertical cross section in which a lower part width is smaller than an upper part width.

According to this configuration, it is possible to improve the cooling performance of the upper part, which is higher in temperature than the lower part of each cylinder liner, and to prevent the lower part from being too cold. For this reason, the temperature distribution in the vertical direction of each cylinder liner at the time of actual operation becomes uniform, the straightness of the cylinder bore at the time of actual operation is improved, and the tension and friction are further reduced.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a cooling system and a cylinder block of an internal combustion engine embodying the present invention will be described below with reference to the drawings. In this embodiment, an example is shown in which the present invention is applied to a multi-cylinder engine mounted on a vehicle such as an automobile, for example, a four-cylinder engine.

As shown in FIG. 1, the cooling system 11 of the internal combustion engine
The cooling water is sent from the radiator 12 to the cylinder block 14 of the engine 13 by the water pump 15 to cool each part of the cylinder block 14. The cooling water after the cooling is returned to the radiator 12, and is cooled by heat exchange with the outside air.

The cylinder block 14 includes a block body 17 having a water jacket 16 and a cylinder head 19 fastened to the block body 17 and having a water jacket 18 therein. The water jacket 16 of the block body 17 has four cylinder bores 30.
(See FIG. 2).

The cooling system 11 is configured such that the entire amount of cooling water sent by the water pump 15 is
9 into the water jacket 18 and the jacket 1
8. Therefore, the water outlet 12a of the radiator 12 and the water inlet 1 of the cylinder head 19
9a is connected via a flow path (piping) 20.
The water inlet 19a of the cylinder head 19 communicates with a water inlet (not shown) of the water jacket 18. A part of the cooling water flowing into the water jacket 18 is supplied between the cylinder bores of the block body 17 (between the bore portions 31 to 3 shown in FIG. 2).
The water flows into the water jacket 16 through the bore water channels 21 to 23 provided in 3).

The cooling water flowing in the water jacket 18 flows out of the water outlet 19b of the cylinder head 19 communicating with the water outlet of the jacket 18. The cooling water is returned to the radiator 12 through a main flow path (pipe) 24 connecting the water outlet 19b and the water inlet 12b of the radiator 12. Meanwhile, water jacket 1
The cooling water flowing through the inside 6 flows out from the water outlet 17 a of the block body 17 communicating with the water outlet of the jacket 16. The cooling water is supplied to the water outlet 17a and the main flow path 2
The radiator 12 is returned to the water inlet 12b of the radiator 12 through a sub flow path (piping) 25 connecting the radiator 4 and the main flow path 24.

Next, a cylinder block 14 of the internal combustion engine to which the cooling system 11 of the internal combustion engine is applied will be described with reference to FIGS. The cylinder block 14 includes the block main body 17 and the cylinder head 19, as shown in FIGS. Each of the inter-bore portions 31 to 33, which is a portion between two adjacent cylinder bores 30, 30,
Bore-to-bore water passages 21 to 23 for connecting the water jackets 16 and 18 to each other are formed.

Further, in the cylinder block 14, as described above, the entire amount of the cooling water sent by the water pump 15 flows into the water jacket 18 of the cylinder head 19 and flows through the jacket 18. At the same time, a part of the cooling water flowing into the water jacket 18 flows into the water jacket 16 of the block main body 17 through the water passages 21 to 23 between the bores, and flows through the jacket 16.

The water jacket 16 of the block body 17 communicates with a water outlet 17a of the block body 17, and has a water outlet 17a through which cooling water flowing in the water jacket 16 flows out. One end of the sub flow path 25 is connected to the water outlet 17a.

The four cylinder bores 3 of the block body 17
Numeral 0 is constituted by the inner peripheral surfaces of the four cylinder liners 41 to 44, respectively, as shown in FIGS. Each of the cylinder liners 41 to 44 is, for example, a cast iron liner formed in a cylindrical shape by centrifugal casting or the like. The cylinder liners 41 and 44 have the same shape, and the cylinder liners 42 and 43 have the same shape.

The lower part 45 of each of the cylinder liners 41 to 44
Are press-fitted into four small-diameter holes 50a formed in the lower portion of the outer wall 50 of the block body 17, as shown in FIG. The upper portion 46 of the outer wall 50 is an inclined surface (inner wall surface) 50b whose inner diameter gradually decreases from the upper surface (head surface) of the block main body 17 downward. Further, the upper portion 46 of each of the cylinder liners 41 to 44 and the outer wall 50 are provided.
The water jacket 16 is formed between the upper surface 46 and the inclined surface 50b, and the upper portions 46 of the cylinder liners 41 to 44 have a wet structure.

As shown in FIGS. 2 and 5, linear mating surfaces 41a to 44a are formed between the bores of the cylinder liners 41 to 44, respectively. That is, each of the cylinder liners 41 and 44 is provided with one mating surface 41a and 44a, respectively, between the bores on one side. On the other hand, the cylinder liners 42 and 43 have
The mating surfaces 42a and 43a are provided between the two bores on both sides.
Are provided respectively. A groove for welding is formed above the mating surfaces 41a to 44a of the cylinder liners 41 to 44 (the groove 41 shown in FIG. 5).
b, 42b).

Above the mating surfaces 41a to 44a of the cylinder liners 41 to 44, grooves for welding (see grooves 41b and 42b shown in FIG. 5) are formed. The mating surfaces of the cylinder liners 41 to 44 (41a,
44a) The four cylinder liners 41 to 44 are integrated by abutting each other and joining the grooves (41b, 42b) above the mating surfaces by welding or the like. In this example, the mating surface 4 of the cylinder liners 41 and 42
1a, 42a, mating surfaces of cylinder liners 42, 43,
The mating surfaces of the cylinder liners 43 and 44 are abutted, and are joined by filler supply laser welding or the like. This welded part (joined part) is indicated by reference numeral 47 in FIG. By such welding, each cylinder liner 41-44
By joining the parts between the cylinder bores of
The inter-bore portions 31 to 33 shown in FIG. 2 are formed.

The thickness of the upper portion 46 of each of the cylinder liners 41 to 44 is equal to the "dimension between bores" over the entire circumference excluding the portions (liner wall portions) below the mating surfaces 41a to 44a.
(See FIG. 2).

Below the welded portion (joined portion) 47 of each of the cylinder liners 41 to 44, the inter-bore water passages 21 to 21 are provided.
23 are formed. In order to form the water passages 21 to 23 between the bores, the mating surfaces 4 of the cylinder liners 41 to 44
The liner walls (liner walls 41c and 42c shown in FIG. 9) below 1a to 44a are recessed. That is, the liner wall portion 41c below the mating surface 41a of the cylinder liner 41
Is recessed to reduce its thickness. Similarly, a liner wall 42c below the mating surface 42a of the cylinder liner 42,
The liner walls below the mating surfaces of the cylinder liners 43 and 44 are also depressed to reduce the wall thickness. With such a configuration, each of two adjacent cylinder liners, for example, the respective liner walls 41c and 42c of the cylinder liners 41 and 42,
A space is formed between the bores, and this space is the inter-bore water passage 21. The same applies to the other water passages 22 and 23 between the bores. These bore water passages 21 to 23 face the water jacket 16 respectively.

As shown in FIGS. 4 and 5, a liner wall portion below the welded portion (joint portion) 47 of each of the cylinder liners 41 to 44 (the liner wall portion 41c shown in FIG. 5). , 42c) are recessed. The gaps between the adjacent cylinder liners formed by the depressions form the water passages 21 to 23 facing the water jacket 16.

As shown in FIGS. 2 and 4, the water jacket 18 of the cylinder head 19 and the water passages 21 to 23 of the bore are provided at the welding portions 47 (see FIG. 5) of the cylinder liners 41 to 44, respectively. Two bore communication holes 51 and 52 to communicate with each other are provided. Each of the inter-bore communication holes 51 and 52 is formed by drill pass processing from the upper surface of the block body 17 to the center of each of the inter-bore water passages 21 to 23. In FIG. 2, three bore portions 31 to 3 are provided.
3 shows the water inlets of the bore communication holes 51 and 52 formed respectively. The water inlets of the communication holes between the bores are connected to the vertical holes 53 and 54 provided in the cylinder head 19.
Through the water jacket 18 (see FIG. 4). In this way, a part of the cooling water flowing into the water jacket 18 of the cylinder head 19 passes through the vertical holes 53 and 54, the bore communication holes 51 and 52, and the bore water passages 21 to 23, respectively. It flows into the jacket 16.

As shown in FIG. 3, the water jacket 16 formed between the outer peripheral surface of the upper portion 46 of each of the cylinder liners 41 to 44 and the inner wall surface of the outer wall 50 has a lower width of the lower portion. It is formed in a V-shaped vertical cross section smaller than the width. For example, the width of the lower portion of the water jacket 16 is not more than 1/3 of the width of the upper portion.

According to the embodiment configured as described above, the following operation and effect can be obtained. (1) The entire amount of the cooling water sent by the water pump 15 flows into the water jacket 18 of the cylinder head 19, and a part of the flowing cooling water passes through the water passage between the cylinder bores 30 and the water of the block body 17. It flows into the jacket 16. That is, a part of the cooling water flowing into the water jacket 18 flows into the water jacket 16 through the vertical holes 53 and 54, the communication holes 51 and 52 between the bores, and the water passages 21 to 23 between the bores. In this way, the cooling water receives heat while flowing in the water jacket 18 of the cylinder head 19 and warms, and the warmed cooling water flows into the water jacket 16 of the block body 17. For this reason, the temperature rise of the wall around each cylinder bore 30 (the wall of each of the cylinder liners 41 to 44) is promoted. Therefore, the warm-up time can be reduced.

(2) Part of the cooling water that has flowed into the water jacket 18 flows between the bores between the cylinder bores 30 (the bores 51 and 52 and the bores 21 to 23).
Through the water jacket 16. For this reason, among the wall portions of the cylinder liners 41 to 44 (wall portions around the respective cylinder bores 30), the inter-bore portion 3 having the highest temperature
Cooling water flows only in the portions 1-33 (portions between the cylinder bores 30). On the other hand, in the water jacket 16 around the portions other than the inter-bore portions 31 to 33 in the wall portions of the cylinder liners 41 to 44, there is almost no flow of the cooling water, and the cooling water is in a stagnant state. . For this reason, among the wall portions of the cylinder liners 41 to 44, the inter-bore portions 31 to 33 having the highest temperature are sufficiently cooled by the cooling water.
On the other hand, portions other than the inter-bore portions 31 to 33 around the cylinder bores 30 are not cooled as much as the inter-bore portions.

This will be described with reference to the temperature distribution around each cylinder bore (each cylinder liner wall temperature) shown in FIG. In the figure, reference numeral 30 indicates one of the cylinder bores of the block body 17, and reference numeral 70 indicates the wall temperature of the cylinder liners 41 to 44, which are walls around the cylinder bore 30. In this temperature distribution, the temperature (° C.) is plotted on the horizontal axis X and the vertical axis Y with the center of the cylinder bore 30 as the origin (0 ° C.).
Is represented. Further, in the same figure, reference numerals A and B indicate the portions between the bores of the wall portions of the cylinder liners 41 to 44, respectively. For example, in the case of a horizontally mounted multi-cylinder engine, if the portion A is a portion between the bores on the thrust side of the wall, the portion B
Is a portion between the bores on the anti-thrust side of the wall. Further, reference numerals C and D in FIG.
This is the rear part.

The cylinder liner wall temperature 9 indicated by the broken line in FIG.
As is clear from FIG. 1, since the cooling water flows only to the portions A and B on the walls of the cylinder liners 41 to 44, the temperatures of the portions A and B are lower than those of the portions C and D. As a result, the wall temperatures of the cylinder liners 41 to 44, which are the walls around each cylinder bore 30, that is, the temperature distribution in the circumferential direction of each cylinder bore 30 becomes uniform. In this way, among the cylinder bores 30, between the bore portions 31 to 33 where the temperature is the highest.
Is cooled by the cooling water, the temperature distribution around each of the cylinder bores 30 becomes uniform, and the roundness of each of the cylinder bores in actual operation is improved. At the same time, each cylinder bore 3
Since the temperature of the entire surrounding wall becomes higher than before, the viscosity of the engine oil decreases early. In this way, the roundness of each cylinder bore 30 at the time of actual operation is improved, and the viscosity of the engine oil is reduced at an early stage.
Friction between the piston ring and the piston ring is reduced, and fuel efficiency can be improved.

(3) The water passage between the bores (the communication hole 5 between the bores)
Since there is no need to provide a water passage communicating the water jackets 16 and 18 other than the water passages 1, 52 and the water passages 21 to 23 between the bores, the configurations of the block body 17 and the cylinder head 19 are simplified, and the cost can be reduced. .

(4) Since the cooling water flowing in the water jacket 16 of the block body 17 is caused to flow out from the water outlet 17a of the block body 17, the sub flow path 25 is connected to the water outlet 17a. Just need. For this reason, a water channel for connecting the water jackets 16 and 18 at the water outlet side is not required, and the configurations of the block body 17 and the cylinder head 19 are correspondingly simplified, and the cost can be reduced.

(5) The lower part 45 of each of the cylinder liners 41 to 44 is provided with a small-diameter hole 50 at the lower part of the outer wall 50 of the block body 17.
a. Further, the outer peripheral surface of the upper portion 46 of each of the cylinder liners 41 to 44 and the inclined surface 50 of the outer wall 50.
b, a water jacket 16 is formed, and upper portions 46 of the cylinder liners 41 to 44 are made wet.

As described above, each of the cylinder liners 41 to 44
Is a press-fitting method with an interference, so that there is no water leakage in the water jacket 16. In addition, since each of the cylinder liners 41 to 44 is a press-fit system, the liner thickness is uniform, and the residual stress is smaller than that of the cast-in liner.
Small bore deformation (deformation of cylinder liner). Thereby, the tension and the friction are further reduced, and the fuel efficiency can be further improved.

(6) Straight mating surfaces 41a to 44a are provided between the cylinder bores of the cylinder liners 41 to 44.
Are formed, and mating surfaces of the cylinder liners are abutted with each other, and the upper portions thereof are joined by welding or the like. In addition, below the welded portion 47, water passages 21 to 23 are formed in the lower liner wall portion. Therefore, the rigidity of each of the cylinder liners 41 to 44 is improved, and
Even when the dimension between the bores is small, it is possible to form the water paths 21 to 23 between the cylinder bores of the respective cylinder liners.

(7) The welded portions 47 of the cylinder liners 41 to 44 are provided with bore communication holes 51 and 52 for connecting the water jacket 18 of the cylinder head 19 and the bore water channels 21 to 23. By providing such a communication hole between bores, the flow rate and the flow velocity of the cooling water for cooling the bore portions 31 to 33 of the cylinder liners 41 to 44 can be sufficiently ensured. For this reason, each cylinder liner 41-
The temperature distribution of the wall of 44 becomes more uniform. Therefore,
The deformation of each cylinder bore is smaller, and the fuel consumption is further reduced.

(8) The water jacket 16 formed between the outer peripheral surface of the upper portion 46 of each of the cylinder liners 41 to 44 and the inclined surface (inner wall surface) 50b of the outer wall 50 has a lower part width equal to the upper part width. It is formed in a smaller V-shaped vertical cross section. Thereby, the lower part 45 of each cylinder liner
It is possible to improve the cooling performance of the upper part 46, which is higher in temperature, and to prevent the lower part 45 from being too cold. For this reason, each cylinder liner 41-
The temperature distribution in the vertical direction of 44 becomes uniform, the straightness of each cylinder bore 30 at the time of actual operation is improved, and the tension and friction are further reduced.

[Modifications] One embodiment of the present invention has been described above. However, the above-described embodiment can be implemented by changing its configuration as described below.

In the above embodiment, the cooling system and the cylinder block of the internal combustion engine according to the present invention are applied to the cylinder block of a four-cylinder engine. However, the present invention can be applied to a multi-cylinder engine other than the four-cylinder engine. . That is, in-line 3, 4, 5 cylinders, V-type 6, 8, 12 cylinders, horizontally opposed 4,
It is applicable to all engines such as five cylinders.

The present invention is also applicable to a modification of the above embodiment as shown in FIG. That is, in this modification, the entire amount of the cooling water sent by the water pump 15 flows in from the water inlet 17b of the block body 17 and flows into the water jacket 18 through the water passages 60 and 61.

In the above embodiment, the cooling water flowing in the water jacket 16 of the block body 17 may be returned to the water jacket 18 of the cylinder head 19 and flow out to the outside. In this case, the cooling water flowing out from the water outlet side of the water jacket 16 is
It is guided to the water jacket 18 through a water channel 62 shown by a chain line in FIG.

The present invention is also applicable to a system in which the cooling system 11 is opened and closed according to the temperature of the cooling water so that the cooling water flowing out of the engine 13 is sent to the radiator 12 only when the cooling system is opened. .

In the above embodiment, the cylinder liner 4
Although the present invention is applied to the press-fit type of Nos. 1 to 44, the present invention is applicable to all cooling systems and cylinder blocks having a water passage between bores communicating the water jackets 16 and 18.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a cooling system and a cylinder block of an internal combustion engine according to an embodiment of the present invention.

FIG. 2 is a plan view showing a block main body of the cylinder block shown in FIG.

FIG. 3 is a longitudinal sectional view showing a portion other than between the bores of the block main body shown in FIG. 2;

FIG. 4 is a longitudinal sectional view showing a space between cylinder bores of the cylinder block shown in FIG. 1;

FIG. 5 is a cross-sectional view showing a joint between two adjacent cylinder liners.

FIG. 6 is an explanatory diagram showing a temperature distribution around a cylinder bore in one embodiment.

FIG. 7 is a schematic configuration diagram showing a modification of the embodiment.

FIG. 8 is a schematic configuration diagram showing a conventional example.

FIG. 9 is an explanatory diagram showing a temperature distribution around a cylinder bore in a conventional example.

[Description of Signs] 11: cooling system, 12: radiator, 12a: water outlet, 1
3 ... engine (internal combustion engine), 14 ... cylinder block,
15: Water pump, 16, 18: Water jacket, 17: Block body, 17a: Water outlet, 17b: Water inlet, 19: Cylinder head, 19a: Water inlet, 19b
... water outlet, 20 ... flow path (pipe), 21-23 ... bore water path, 24 ... main flow path (pipe), 25 ... sub flow path (pipe), 30 ... cylinder bore, 31-33 ... bore section, 4
1 to 44: cylinder liner, 41a to 44a: linear mating surface, 41b, 42b: groove, 41c, 42c: liner wall, 45: lower part of cylinder liner, 46: upper part of cylinder liner, 47: welded part (Joining portion), 50: outer wall, 50a: small-diameter hole, 50b: inclined surface, 51, 52: communication hole between bores, 51a, 52a: water inlet, 53, 54: vertical hole, 60, 61: water channel.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) F01P 3/02 F01P 3/02 RW F02F 1/14 F02F 1/14 D 1/16 1/16 A (72) Invention ▼ Yoshikazu Kazuya Shima 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation (72) Inventor Hiroyuki Izawa 1 Toyota City Toyota City, Aichi Prefecture Toyota Motor Corporation (72) Inventor Kazunari Takenaka Toyota Motor Co., Ltd. 1 Toyota Town, Aichi Prefecture Toyota Motor Co., Ltd. (72) Inventor Zenichi 1 Toyota Town Toyota City Aichi Prefecture Toyota Motor Co., Ltd. F-term (reference) 3G024 AA01 AA27 CA05 DA18

Claims (8)

[Claims] 1. A cooling water sent from a radiator to a cylinder block of an internal combustion engine by a water pump is caused to flow through respective water jackets of a block body and a cylinder head constituting the cylinder block to cool respective parts of the cylinder block. In a cooling system of an internal combustion engine in which cooling water after cooling is returned from the cylinder block to the radiator, the entire amount of cooling water sent to the cylinder block by the water pump is caused to flow through a water jacket of the cylinder head. A cooling system for an internal combustion engine, wherein a part of cooling water flowing in a jacket is made to flow into a water jacket of the block main body through an inter-bore water passage provided between cylinder bores of the block main body. 2. A block body having a water jacket formed around a plurality of cylinder bores, and a cylinder head having a water jacket therein and fastened to the block body, wherein the cylinder body is provided between the cylinder bores. In the cylinder block of the internal combustion engine, which has a water passage between the bores communicating the water jackets and in which the cooling water sent from the water pump flows through the two water jackets, the total amount of the cooling water sent by the water pump is equal to the amount of the cylinder head. The cooling water flowing into the water jacket flows into the water jacket, and a part of the cooling water flowing into the water jacket flows into the water jacket of the block main body through the water passage between the bores. Cylinder block of an internal combustion engine. 3. The cylinder block of an internal combustion engine according to claim 2, wherein the cooling water flowing in the water jacket of the block main body is caused to flow out of the block main body to the outside. 4. The cooling water flowing in the water jacket of the block main body is returned to the water jacket of the cylinder head and is discharged from the cylinder head side to the outside. Cylinder block of internal combustion engine. 5. The plurality of cylinder bores are each constituted by a cylinder liner, and a lower portion of each cylinder liner is press-fitted into each cylinder of the block body, and an upper outer peripheral surface of each cylinder liner and an inner wall surface of an outer wall of the block body. The cylinder block of an internal combustion engine according to any one of claims 2 to 4, wherein a water jacket is formed between the first and second cylinder lines to form an upper portion of each cylinder liner in a wet structure. 6. A linear mating surface is formed between the cylinder bores of each of the cylinder liners. The mating surfaces of each of the cylinder liners abut each other, and the upper portion thereof is joined. The cylinder block for an internal combustion engine according to any one of claims 2 to 5, wherein a liner between bores is formed by lowering a liner wall portion below the liner. 7. The connecting portion of each of the cylinder liners,
The cylinder block of an internal combustion engine according to claim 6, wherein at least one communication hole between bores is provided for communicating a water jacket on the cylinder head side fastened to the block body and the water passage between bores. 8. The water jacket formed between an upper outer peripheral surface of each of the cylinder liners and an inner wall surface of an outer wall of the block main body has a V-shaped lower portion whose width is smaller than its upper portion. The cylinder block of an internal combustion engine according to any one of claims 5 to 7, wherein the cylinder block is formed in a vertical section.