JPH11182241A - Cooling device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control the flow of cooling water on the cylinder block side according to the temperature of cooling water without needing a control means from the outside. SOLUTION: A radiator 15 is interposed in a main cooling water passage 14 between a first cooling water outlet 12 and a main cooling water inlet 11 of a water jacket 4 on the cylinder head side, and a by-pass passage 17 branching off from this part is connected to a second cooling water outlet 13. A cooling water inlet 7 and a cooling water outlet 8 are in positions where pressure drop caused by the outflow of cooling water from the second cooling water outlet 13 acts almost equally, and the first cooling water outlet 12 is close to the cooling water outlet 8. When a passage control valve 18 is on the bypass passage 17 side at the time of low temperature, pressure difference is not generated to the cooling water inlet 7 and cooling water outlet 8, so that the flow of cooling water on the cylinder block 1 side stops. When the temperature becomes high and cooling water flows out of the first cooling water outlet 12, pressure difference is generated to the cooling water inlet 7 and cooling water outlet 8, and cooling water flows.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling device for an internal combustion engine, and more particularly to a water-cooled cooling device.

[0002]

2. Description of the Related Art Many internal combustion engines such as automobile engines are provided with a water-cooled cooling system by forcibly circulating cooling water.
The heat load is high, and active cooling is required to avoid abnormal combustion. Excessive cooling is not preferable on the cylinder block side from the viewpoint of reduction of friction loss and composition of exhaust gas.

For this reason, Japanese Patent Application Laid-Open No. Hei.
As described in Japanese Patent Laid-Open Publication No. 5 (1993) -5, etc., a cooling device having a configuration in which a water jacket on a cylinder block side and a water jacket on a cylinder head side are separated and independent from each other, and cooling water flows independently of each other is proposed. Have been. In this type, for example, cooling water discharged from a water pump is guided in parallel to both the cylinder head side and the cylinder block side, and a variable orifice mechanism is provided in one of the flow paths, so that the cylinder head side and the cylinder The flow ratio with the block side is variably controlled. Therefore, for example, when the temperature of the engine is low, by stopping the flow of the cooling water to the cylinder block side, the temperature of the cylinder wall can be quickly raised.

[0004]

However, in such a conventional cooling device, a variable element such as a variable orifice mechanism and its control means must be used to suppress the cooling water circulation on the cylinder block side at low temperatures. Required, and the configuration becomes complicated.

Accordingly, the present invention provides a cooling device for an internal combustion engine in which the flow rate on the cylinder block side is automatically changed by using the flow path switching between the radiator side and the bypass passage side based on the cooling water temperature. It is intended to provide.

[0006]

According to a first aspect of the present invention, there is provided a cooling apparatus for an internal combustion engine, which is formed in a cylinder block and through which cooling water can flow between a cooling water inlet and a cooling water outlet. A water jacket, a cylinder head side water jacket formed inside the cylinder head and communicating with the cylinder block side water jacket via the cooling water inlet and the cooling water outlet, and a first cooling water of the cylinder head side water jacket. One end is connected to a main cooling water passage provided between the outlet and the main cooling water inlet and having a radiator interposed, and a second cooling water outlet of the cylinder head side water jacket, and bypasses the radiator. Through the bypass passage joining the main cooling water passage and the bypass passage or the radiator. A water pump that circulates cooling water between the water jacket and the dahead-side water jacket, and a thermostat valve that operates based on the temperature of the cooling water and switches the flow path of the cooling water to the bypass passage side at a low temperature and to the radiator side at a high temperature. And the like. The cooling water inlet and the cooling water outlet are located at locations where the pressure drop caused by the cooling water outflow from the second cooling water outlet acts substantially evenly, and are associated with the cooling water outflow from the first cooling water outlet. It is arranged at a position where the pressure drop acts relatively strongly on the cooling water outlet.

That is, when the temperature of the cooling water is low, the flow path control valve guides the cooling water to the bypass passage side in order to suppress heat radiation from the radiator. Therefore, with the rotation of the water pump, the cooling water flowing out of the water jacket on the cylinder head side circulates through the bypass passage so as to return to the water jacket on the cylinder head side again. At this time, the cooling water flows out of the cylinder head side water jacket through the second cooling water outlet to which the bypass passage is connected, and the pressure near the second cooling water outlet drops in the cylinder head side water jacket. I do. On the other hand, at the first cooling water outlet, there is basically no flow of cooling water. Therefore, there is almost no pressure difference between the cooling water inlet and the cooling water outlet of the water jacket on the cylinder block side, and therefore, even if the cooling water circulates on the cylinder head side, the cooling water almost stays in the water jacket on the cylinder block side. Kept in state. This allows
The temperature of the cylinder wall rises early.

When the cooling water temperature is higher than a predetermined temperature,
The flow path control valve composed of a thermostat valve or the like guides the cooling water to the radiator side, and the cooling water circulates between the water jacket on the cylinder head side and the radiator. At this time, since the cooling water flows out of the cylinder head side water jacket through the first cooling water outlet to which the main cooling water passage is connected, the cooling water near the first cooling water outlet in the cylinder head side water jacket. The pressure drops. On the other hand, at the second cooling water outlet, there is basically no flow of the cooling water. Therefore, the pressure at the cooling water outlet of the water jacket on the cylinder block side becomes relatively lower than the pressure at the cooling water inlet, and a pressure difference is generated between the two. Therefore, cooling water flows from the cooling water inlet to the cooling water outlet in the water jacket on the cylinder block side. In other words, simultaneously with the circulation of cooling water on the cylinder head side, the water jacket on the cylinder block side also
Cooling water flows, and each part of the cylinder block such as the cylinder wall is reliably cooled.

According to a second aspect of the present invention, there is provided a cooling device for an internal combustion engine, wherein the water jacket is formed in a cylinder block and through which cooling water can flow between a cooling water inlet and a cooling water outlet. A cylinder head side water jacket formed inside the head and communicating with the cylinder block side water jacket via the cooling water inlet and the cooling water outlet; a main cooling water outlet of the cylinder head side water jacket; and a first cooling water A main cooling water passage provided between the main cooling water passage and a radiator interposed between the main cooling water passage and the second cooling water inlet of the cylinder head side water jacket; Through the bypass passage having one end connected to the cylinder and the bypass passage or the radiator. A water pump that circulates cooling water between the cooling water and the water jacket, and a flow that operates based on the temperature of the cooling water and switches the flow path of the cooling water to the bypass passage at a low temperature and to the radiator at a high temperature. A path control valve. The cooling water inlet and the cooling water outlet are located at positions where the pressure rise caused by the cooling water inflow from the second cooling water inlet acts substantially evenly, and are associated with the cooling water inflow from the first cooling water inlet. It is arranged at a position where the pressure rise acts relatively strongly on the cooling water inlet.

That is, in the present invention, the first head on the cylinder head side is linked to the switching of the flow path by the flow path control valve.
One of the cooling water inlet and the second cooling water inlet is selected. When the temperature is low, the second cooling water inlet is selected, so that there is almost no pressure difference between the cooling water inlet and the cooling water outlet on the cylinder block side, and the cooling water does not flow through the water jacket on the cylinder block side. Further, at the time of high temperature, the first cooling water inlet is selected, so that a pressure difference is generated between the cooling water inlet and the cooling water outlet on the cylinder block side, and the flow of the cooling water is generated in the water jacket on the cylinder block side. .

According to the third aspect of the present invention, the cooling water inlet and the cooling water outlet are located at one end of the cylinder block, respectively. A water jacket on the cylinder block side is formed so as to flow in a U-turn shape around the cylinder row.

In a further embodied invention, a partition wall is provided in the water jacket at one end of the cylinder block so that the cooling water inlet and the cooling water outlet are not short-circuited. That is, the water jacket on the cylinder block side is partitioned into the cooling water inlet side and the cooling water outlet side by the partition at one end of the cylinder block, so that the cooling water surely flows in a U-turn shape.

According to the invention of claim 5, the partition wall and the cylinder wall are separated by a minute gap. As a result, thermal deformation of the cylinder wall having a high thermal load is not restricted by the partition wall, and a decrease in roundness is avoided.

According to a sixth aspect of the present invention, the cooling water inlet and the cooling water outlet are open at the top surface of the cylinder block, and communicate with the cylinder head side water jacket through a communication hole opened at the cylinder head bottom surface. ing.

According to a seventh aspect of the present invention, the cooling water inlet or the cooling water outlet communicates with the cylinder head side water jacket via an external pipe. In this case, it is possible to connect the tip of the external pipe to, for example, the tip of the main cooling water passage or the bypass passage, that is, the position near the cylinder head.

[0016]

According to the cooling device for an internal combustion engine according to the present invention, the cooling water always flows to the cylinder head side where the heat load is high, while the cooling water temperature is high in the cylinder block side. Only the cooling water flows, and almost no cooling water flows at low temperatures. Therefore, the temperature of the cylinder wall can be raised early at the time of cold start, and reliable cooling can be performed at the time of high load. In particular, in the present invention, since the flow of the cooling water on the cylinder block side is automatically controlled as the flow path control valve switches the flow path to the radiator side or the bypass passage side, a variable orifice mechanism such as No need for variable elements and their control means,
The configuration can be simplified.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a cooling device according to the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows a first embodiment of a cooling device according to the present invention.

The illustrated example is applied to an in-line four-cylinder internal combustion engine, in which a cylinder block-side water jacket 2 is formed inside a cylinder block 1 having four cylinders, and disposed above the cylinder jacket. The cylinder head 3 has a water jacket 4 on the cylinder head side.
Are formed. As shown in FIG. 2, the cylinder block side water jacket 2 is formed so as to surround the cylinder wall 5. In particular, the cylinder walls 5 of the four cylinders are connected in the cylinder row direction as a Siamese type. Further, at one end of the cylinder block 1, there is provided a partition wall 6 connecting the cylinder wall 5 and the cylinder block end wall along the cylinder row direction.
As a whole, the cooling water flows in a U-turn shape. A cooling water inlet 7 is provided at one end of the U-shaped flow path, and a cooling water outlet 8 is provided at the other end. That is, the cooling water inlet 7 and the cooling water outlet 8 are formed side by side at one end of the cylinder block 1, specifically, at the rear end. Each has an opening. The partition 6 can be formed at the same time when the cylinder block 1 is cast, but another member may be attached after the casting.

Two communication holes 9 and 10 corresponding to the cooling water inlet 7 and the cooling water outlet 8 are provided on the cylinder head 3 side.
The cylinder block side water jacket 2 communicates with the cylinder head side water jacket 4 via the communication holes 9, 10.

Water jacket 4 on cylinder head side
Has a main cooling water inlet at a front end thereof, that is, an end opposite to the cooling water inlet 7 and the cooling water outlet 8. 11 are provided. Further, a first cooling water outlet 12 and a second cooling water outlet 13 are provided at the rear end.
Here, the main cooling water inlet 11 and the second cooling water outlet 13 are located on the end face of the cylinder head 3, and in particular, the second cooling water outlet 13 is substantially equal to the communication holes 9 and 10 on the bottom surface, respectively. It is provided at a position that is a distance. On the other hand, the first cooling water outlet 12 is connected to the side surface of the cylinder head 3, and is particularly arranged on the side surface of the cylinder block 1 closer to the cooling water outlet 8. In other words, the first cooling water outlet 12 opens above the communication hole 10 corresponding to the cooling water outlet 8.

The first cooling water outlet 12 and the main cooling water inlet 1
1, a main cooling water passage 14 is provided, and a radiator 15 is interposed midway. In this embodiment, a water pump 16 that is constantly driven by the engine output is disposed between the radiator 15 and the main cooling water inlet 11, and circulates cooling water to the water jacket 4 on the cylinder head side. I have. Note that an electric pump can also be used as the water pump 16.
Further, a bypass passage 17 is provided to bypass the radiator 15, one end of which is connected to the second cooling water outlet 13, and the other end of which is a main passage between the radiator 15 and the water pump 16. Cooling water passage 1
Merges with 4. The junction is provided with a flow path control valve 18 that switches the flow path of the cooling water to the radiator 15 side or the bypass passage 17 side according to the cooling water temperature. The flow path control valve 18 is composed of, for example, a well-known thermostat valve using thermo wax, and connects the bypass passage 17 to the water pump 16 at a low temperature, and connects the radiator 15 to the water pump 16 at a high temperature.
It is designed to communicate with The flow path control valve 18
As an alternative, it is also possible to use an electromagnetic valve or the like that performs a switching operation based on an external control signal.

Next, the operation of the first embodiment will be described.

When the temperature of the cooling water is lower than the set temperature of the flow path control valve 18, such as immediately after the cold start of the engine, the cooling water flows through the cylinder head without passing through the radiator 15 with the rotation of the water pump 16. The water circulates from the side water jacket 4 through the bypass passage 17. That is, the water is drawn out from the second cooling water outlet 13, and is again sent from the main cooling water inlet 11 into the cylinder head side water jacket 4 by the water pump 16 via the bypass passage 17. Thereby, the periphery of the combustion chamber of the cylinder head 3 is always cooled. In the water jacket 4 on the cylinder head side, the pressure is relatively high in the vicinity of the main cooling water inlet 11 into which the cooling water flows, and the second cooling water flows out therefrom.
The pressure becomes relatively low near the cooling water outlet 13. The cooling water inlet 7 and the cooling water outlet 8 on the side of the cylinder block 1 have the second cooling water outlet 1 close to them.
As described above, since the communication holes 9 and 10 are located at substantially equal distances from the second cooling water outlet 13, the effect of the pressure drop is substantially equal for both. I do. Therefore, the pressures of the cooling water inlet 7 and the cooling water outlet 8 on the cylinder block 1 side are substantially equal to each other. FIG. 3 is an explanatory diagram showing a pressure relationship of each part,
As shown in the figure, in the cold state, the pressure P
7 and the pressure P8 at the cooling water outlet 8 are substantially equal. for that reason,
In the water jacket 2 on the cylinder block side, cooling water hardly flows. That is, the cooling water basically stays, and the temperature of the cylinder wall 5 rises quickly. In FIG. 3, P12 is the pressure at the first cooling water outlet 12, and P13 is the pressure at the second cooling water outlet 13.

When the temperature of the cooling water rises and becomes higher than the set temperature of the flow path control valve 18, the flow path of the cooling water is switched to the side of the main cooling water passage 14 passing through the radiator 15, and the cylinder head side water jacket 4 Cooling water circulates between the cooling water and the radiator 15. That is, the water is drawn from the first cooling water outlet 12, passes through the radiator 15, and is again sent from the main cooling water inlet 11 into the water jacket 4 on the cylinder head side by the water pump 16. Thereby, the periphery of the combustion chamber of the cylinder head 3 is always cooled.
In the water jacket 4 on the cylinder head side, the pressure is relatively high near the main cooling water inlet 11 into which the cooling water flows, and the pressure is relatively low near the first cooling water outlet 12 from which the cooling water flows. However, with respect to the cooling water inlet 7 and the cooling water outlet 8 on the cylinder block 1 side, since the cooling water outlet 8 is closer to the first cooling water outlet 12, the pressure drop of the first cooling water outlet 12 is: It acts more strongly on the cooling water outlet 8 than on the cooling water inlet 7. Therefore, as shown in FIG. 3, the pressure P of the cooling water inlet 7 on the cylinder block 1 side is increased.
7 and the pressure P8 of the cooling water outlet 8 are relatively high in the former and relatively low in the latter. Therefore, cooling water flows in the water jacket 2 on the cylinder block side due to the pressure difference. That is, the cooling water flows in a U-turn shape around the cylinder row from the cooling water inlet 7 to the cooling water outlet 8, and the cylinder wall 5 can be reliably cooled.

As described above, in the above embodiment, the flow and stoppage of the cooling water in the water jacket 2 on the cylinder block side are automatically controlled in conjunction with the switching operation of the flow path control valve 18 such as a thermostat valve. In addition, it is possible to achieve both promotion of warm-up at low temperature and reliable cooling at high load.

When the flow path control valve 18 is a thermostat valve made of thermo wax, the flow path generally switches gradually across a set temperature as shown by a broken line a in FIG. For example, when a solenoid valve is used as 18, it is desirable that the characteristic be such that the flow path is clearly switched at a set temperature as shown by a solid line b. In this manner, for example, in a hybrid vehicle or the like in which the internal combustion engine stops during traveling, it is possible to prevent the cooling water from flowing to the radiator 15 even after the internal combustion engine is stopped and the temperature of the cooling water to drop below the set temperature. .

Incidentally, in order to surely stop the flow of the cooling water in the cylinder block side water jacket 2 at a low temperature, the cooling water inlet 7 and the cooling water outlet 8 when the second cooling water outlet 13 is used. It is necessary to make the pressure difference with the pressure as small as possible. The influence of the pressure acting on the cooling water inlet 7 and the cooling water outlet 8 as the cooling water flows out from the second cooling water outlet 13 depends on the distance, the shape of the water jacket 4 on the cylinder head side, the passage resistance, and the like. The optimal position is determined by simulation or the like, since it depends on the presence or absence of such a part.

FIG. 5 illustrates the influence of the height of the water jacket 4 on the cylinder head side as an example. The height at the cooling water outlet 8 is higher than the height H1 at the cooling water inlet 7. When the height H2 is lower, the lower the height, the lower the pressure tends to be. Therefore, in order to equalize the influence of the pressure from the second cooling water outlet 13,
It is necessary to arrange the second cooling water outlet 13 at a position higher in height, that is, at a position closer to the cooling water inlet 7 as shown by a solid line from the position of the broken line where the distances are equal to each other.

FIG. 6 shows a second embodiment of the present invention. In this embodiment, the cylinder block 1
Are formed on the top surface of the cylinder head 3 and the bottom surface of the cylinder head 3, respectively. The cooling water inlet 7, the cooling water outlet 8 on the cylinder block 1 side and the cylinder head 3 side The other openings 21 are closed by gaskets 22 except for the openings 21 corresponding to the communication holes 9 and 10. That is, a pair of communication holes 23 and 24 is formed at one end of the gasket 22 sandwiched between the cylinder block 1 and the cylinder head 3, and the opening 21 at a position overlapping with the communication hole 23 and the cooling water inlet 7. The cooling water outlet 8 and the communication holes 9 and 10 are provided.
Therefore, in this embodiment, the communication hole 2 of the gasket 22 is
The flow rate of the cooling water in the water jacket 2 on the cylinder block side can be adjusted by the positions and opening areas of the cylinders 3 and 24, thereby increasing the degree of freedom in design.

FIG. 7 shows a third embodiment of the present invention. In this embodiment, the cooling water inlet 7 on the cylinder block 1 side is opened at the top surface of the cylinder block 1, whereas the cooling water outlet 8 is located on the side of the cylinder block 1 and has an external piping 31. Is connected to the main cooling water passage 14 immediately after the first cooling water outlet 12 on the cylinder head 3 side. In addition, only the communication hole 9 corresponding to the cooling water inlet 7 is provided on the bottom surface of the cylinder head 3.

Accordingly, in this embodiment, when the cooling water flows through the radiator 15 at a high temperature, the cooling water outlet 8 directly communicates with the first cooling water outlet 12, so that the cooling water outlet 8 The pressure is reliably reduced, and a greater pressure difference between the cooling water inlet 7 and the cooling water outlet 8 on the cylinder block 1 side can be obtained. Therefore, a large flow rate flowing through the cylinder block 1 at a high temperature can be secured. In this configuration, a slight pressure difference occurs between the cooling water inlet 7 and the cooling water outlet 8 even when the cooling water is flowing out of the second cooling water outlet 13 at a low temperature, and the cylinder block 1 side Although the flow of the cooling water is generated, the flow at this time is very gentle and does not impair the early warm-up.

FIG. 8 shows a fourth embodiment of the present invention. In the fourth embodiment, the flow on the cylinder block 1 side is controlled using the pressure change on the inlet side of the cooling water of the cylinder head 3. The configuration of the cylinder block 1 is basically the same as that of the first embodiment described above, and a cooling water inlet 7 and a cooling water outlet 8 are provided on the top surface. In the bottom surface of the cylinder head 3, communication holes 9, 10 corresponding to the cooling water inlet 7 and the cooling water outlet 8, respectively, are formed, and communicate with the water jacket 4 on the cylinder head side.

In this embodiment, a single cooling water outlet, that is, a main cooling water outlet 41 is provided at the end of the cylinder head 3 opposite to the cooling water inlet 7 and the like. At the side end, two cooling water inlets, that is, a first cooling water inlet 42 and a second cooling water inlet 43 are provided. Here, the second cooling water inlet 43 is located at the end face of the cylinder head 3, and in particular, is provided at a position that is substantially equal to the communication holes 9 and 10 on the bottom face. On the other hand, the first cooling water inlet 42 is connected to the side surface of the cylinder head 3, and is particularly arranged on the side surface of the cylinder block 1 closer to the cooling water inlet 7. In other words, the first cooling water inlet 42 opens above the communication hole 9 corresponding to the cooling water inlet 7.

The main cooling water outlet 41 and the first cooling water inlet 4
2, a main cooling water passage 1 having a radiator 15
4 and a water pump 16 is provided upstream thereof.
Is arranged. A bypass passage 17 branches from a position between the water pump 16 and the radiator 15 so as to bypass the radiator 15.
The tip is connected to the second cooling water inlet 43.
The branch of the bypass passage 17 and the radiator 15
Between the radiator 15 and the bypass passage 17 in accordance with the temperature of the cooling water. In this embodiment, the flow path control valve 18 is configured to simply open and close the main cooling water passage 14, and is opened when the temperature is equal to or higher than a set temperature to allow the flow of the cooling water to the radiator 15. ing.

In the fourth embodiment, when the temperature of the cooling water is lower than the set temperature of the flow path control valve 18, the rotation of the water pump 16 causes the cooling water to flow through the second cooling water inlet 4.
3 flows into the water jacket 4 on the cylinder head side. At this time, the vicinity of the second cooling water inlet 43 is the main cooling water outlet 4
Although the pressure is higher than near 1, as described above, since the communication holes 9 and 10 are located at substantially the same distance from the second cooling water inlet 43, the influence of the pressure increase acts substantially equally on both. Accordingly, the pressure of the cooling water inlet 7 and the pressure of the cooling water outlet 8 on the cylinder block 1 side are substantially equal to each other, and almost no flow of the cooling water occurs as in the above-described embodiments.

When the temperature of the cooling water rises and becomes higher than the set temperature of the flow path control valve 18, the cooling water flows into the cylinder head side water jacket 4 from the first cooling water inlet 42 through the radiator 15. I do. Accordingly, the cooling water inlet 7 and the cooling water outlet 8 on the cylinder block 1 side
In, the pressure of the cooling water inlet 7 is relatively higher than that of the cooling water outlet 8, and a pressure difference is generated between the two.
Therefore, due to this pressure difference, cooling water flows in the water jacket 2 on the cylinder block side.

FIG. 9 shows another embodiment of the partition 6 on the cylinder block 1 side. In this embodiment, as shown in the figure, a minute gap 51 is provided between the tip of the partition 6 and the cylinder wall 5, whereby the partition 6
And the cylinder wall 5 are separated. The minute gap 51 is desirably 1 mm or less so that a short circuit of the cooling water does not occur between the cooling water inlet 7 and the cooling water outlet 8.

That is, if the partition wall 6 is integrated with the cylinder wall 5, the deformation of the cylinder wall 5 is restrained by the partition wall 6 when the cylinder wall 5 thermally expands.
As indicated by an imaginary line at 0, both sides of the partition wall 6 of the cylinder wall 5 bulge to the outer peripheral side, and the roundness of the cylinder wall 5 decreases. On the other hand, if a minute gap 51 is provided between the partition wall 6 and the cylinder wall 5 as shown in FIG. 9, a decrease in the roundness of the cylinder wall 5 is suppressed.

[Brief description of the drawings]

FIG. 1 is a configuration explanatory view showing a first embodiment of a cooling device according to the present invention.

FIG. 2 is a partially cutaway perspective view showing the configuration of a cylinder block side water jacket.

FIG. 3 is an explanatory diagram showing the relationship between the pressures of various parts in a cold state and in a warmed state.

FIG. 4 is a characteristic diagram showing switching characteristics of a flow path control valve.

FIG. 5 is an explanatory diagram when the heights of water jackets are different.

FIG. 6 is a configuration explanatory view showing a second embodiment of the cooling device according to the present invention.

FIG. 7 is a configuration explanatory view showing a third embodiment of the cooling device according to the present invention.

FIG. 8 is a configuration explanatory view showing a fourth embodiment of the cooling device according to the present invention.

FIG. 9 is an explanatory view of a water jacket on a cylinder block side showing an embodiment in which a minute gap is provided between a partition wall and a cylinder wall.

FIG. 10 is an explanatory view showing a deformation when the partition wall and the cylinder wall are connected.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Cylinder block 2 ... Cylinder block side water jacket 3 ... Cylinder head 4 ... Cylinder head side water jacket 7 ... Cooling water inlet 8 ... Cooling water outlet 11 ... Main cooling water inlet 12 ... First cooling water outlet 13 ... Second cooling Water outlet 14: Main cooling water passage 15 ... Radiator 16 ... Water pump 17 ... Bypass passage 18 ... Flow control valve

Claims (7)

[Claims] 1. A water jacket formed in a cylinder block and through which a cooling water can flow between a cooling water inlet and a cooling water outlet, and a cooling water inlet formed in a cylinder head and inside the cylinder head. And a cylinder head side water jacket communicating with the cylinder block side water jacket via a cooling water outlet, and a radiator provided between a first cooling water outlet and a main cooling water inlet of the cylinder head side water jacket. An interposed main cooling water passage, a bypass passage having one end connected to the second cooling water outlet of the cylinder head side water jacket, and bypassing the radiator to join the main cooling water passage; Alternatively, circulate the cooling water through the radiator and the water jacket on the cylinder head side. A water pump that operates based on the temperature of the cooling water, and a flow path control valve that operates based on the temperature of the cooling water and switches the flow path of the cooling water to the bypass passage at a low temperature and the radiator at a high temperature. The inlet and the cooling water outlet are located at positions where the pressure drop caused by the outflow of the cooling water from the second cooling water outlet acts substantially uniformly, and the pressure drop caused by the outflow of the cooling water from the first cooling water outlet is the cooling water. A cooling device for an internal combustion engine, which is disposed at a position that relatively strongly acts on an outlet. 2. A water jacket formed in a cylinder block and through which cooling water can flow between a cooling water inlet and a cooling water outlet, and a cooling water inlet formed in a cylinder head and inside the cylinder head. And a cylinder head side water jacket communicating with the cylinder block side water jacket via a cooling water outlet, and a radiator provided between a main cooling water outlet and a first cooling water inlet of the cylinder head side water jacket. An interposed main cooling water passage, a bypass passage branched from the main cooling water passage so as to bypass the radiator, and having one end connected to a second cooling water inlet of the cylinder head side water jacket; Cooling water between the water jacket and the cylinder head side through the bypass passage or radiator A water pump that circulates water, and a flow path control valve that operates based on the cooling water temperature and switches the flow path of the cooling water to the bypass passage side at low temperature and to the radiator side at high temperature. The cooling water inlet and the cooling water outlet are located at positions where the pressure rise due to the inflow of the cooling water from the second cooling water inlet substantially uniformly acts, and the pressure rise due to the inflow of the cooling water from the first cooling water inlet. A cooling device for an internal combustion engine, which is disposed at a position that relatively strongly acts on a cooling water inlet. 3. The cylinder block side water jacket is formed such that the cooling water inlet and the cooling water outlet are respectively located at one end of the cylinder block, and the cooling water flows in a U-turn around the cylinder row. The cooling device for an internal combustion engine according to claim 1 or 2, wherein: 4. At one end of the cylinder block, a cooling water inlet and a cooling water outlet are not short-circuited.
4. The cooling device for an internal combustion engine according to claim 3, wherein a partition is provided in the water jacket. 5. The cooling device for an internal combustion engine according to claim 4, wherein said partition and said cylinder wall are separated by a minute gap. 6. The cooling water inlet and the cooling water outlet open at the top surface of the cylinder block, and communicate with the cylinder head side water jacket via a communication hole opened at the cylinder head bottom surface. Claim 1
The cooling device for an internal combustion engine according to any one of claims 1 to 5. 7. The cooling device for an internal combustion engine according to claim 1, wherein the cooling water inlet or the cooling water outlet communicates with a water jacket on a cylinder head side through an external pipe. .