JPH08296439A - Cooling device for internal combustion engine - Google Patents

Abstract

PURPOSE: To inexpensively realize a cooling device for an internal combustion engine in which cooling control is carried out in accordance with the warming condition. CONSTITUTION: A discharge side of a water pump 5 is connected to a water jacket 4 on the cylinder block side. The device is provided both with a first cooling-water passage starting from the water jacket 4 on the cylinder block side, passing through a communicating part 6 in the vicinity of the water pump 5, entering the water jacket 2 on the cylinder head side, bypassing a radiator 8, and entering the water pump 5 through a thermostat valve 9, and with a second cooling-water passage starting from the water jacket 4 on the cylinder block side, and entering the water pump 5 through the radiator 8 and the thermostat valve 9. Changeover is carried out by the thermostat valve 9 in such a way that during warming, cooling water is passed only to the first cooling-water passage, while after warming, the cooling water is passed through both the first and second cooling-water passages.

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-cooling cooling device which uses two cooling water paths and is capable of cooling according to a warm-up condition.

[0002]

2. Description of the Related Art Conventionally, as a cooling device for an internal combustion engine, which selectively uses two cooling water paths in accordance with the warm-up state, there is one as shown in FIG. 10, the cylinder head
The water jacket 32 on the 31 side and the water jacket 34 on the cylinder block 33 side are formed independently of each other, and both water jackets are provided to the discharge side of the water pump 35.
32 and 34 are connected in parallel.

The cooling water that has passed through the water jackets 32 and 34 merges and is circulated to the water pump 35 via the radiator 36 or bypassing the radiator 36 by the bypass passage 37. Circulation / circulation to the radiator 36 is selected by a thermostat valve 38 provided at the confluence of the outlet of the radiator 36 and the bypass passage 37.

A valve 39 is provided on the upstream side of a confluence portion where the cooling water passing through the cylinder block side water jacket 34 joins the cooling water passing through the cylinder head side water jacket 32. With this configuration, after warming up, as shown in FIG. 11, the cooling water is passed through each of the water jackets 32 and 34, and the cooling water after passing through is merged and circulated to the radiator 36 to radiate the cooling water. Plan.

During warm-up, the thermostat valve 38 closes the outlet passage of the radiator 36, while the bypass passage 37 is opened, so that the cooling water that has passed through the water jackets 32 and 34 and merged together is cooled by the radiator 36. Is bypassed and can be circulated to the water pump 35. Further, when the valve 39 is closed, as shown in FIG. 12, the passage of the cooling water in the cylinder block side water jacket 34 is blocked, and as a result, the cooling water is circulated only in the cylinder head side water jacket 32. That is, the cooling water stays in the water jacket 34 on the cylinder block side. Therefore, if the valve 39 is selectively closed according to the engine load, the temperature of the cooling water, etc., the inner wall temperature of the bore can be set higher and cooling according to the warm-up state becomes possible.

FIG. 13 shows a Japanese Patent Application No. 6-286 filed by the present applicant.
FIG. 6 is a system configuration diagram of a cooling device proposed in No. 620. A water jacket 32 that circulates cooling water in the cylinder head 31 and a water jacket 34 that circulates cooling water in the cylinder block 33 are respectively formed, and the water jackets 32 and 34 are connected to each other by a communication portion 40. It

The outlet 32a formed in the water jacket 32 on the cylinder head side bypasses the radiator 36 via the thermostat valve 41 and is connected to the suction side of the water pump 35 by the cooling water passage 42 to discharge the water pump 35. The side is connected only to the cylinder head side water jacket 32. In addition, the outlet 34 a formed in the water jacket 34 on the cylinder block side is provided on the inlet side 36 of the radiator 36.
It is connected to a through a cooling water passage 43.

The outlet side 36b of the radiator 36 is provided with a cooling water passage.
It is connected to the thermostat valve 41 via 44, merges with the cooling water passage 42, and is connected to the water pump 35. The thermostat valve 41 selectively opens the cooling water passage 42 and the cooling water passage 44 in accordance with the cooling water temperature, so that only one of the passages is connected to the water pump 35 and bypasses the radiator 36. The circulation path of the cooling water and the circulation path of the cooling water via the radiator 36 are switched.

When the circulation of the cooling water through the cooling water passage 44 is blocked by the thermostat valve 41 during warm-up, the circulation path from the water jacket 34 on the cylinder block side to the water pump 35 via the radiator 36 is cut off. As the cooling water entered the water jacket 32 from the water pump 35 into the cylinder head side water jacket 32,
As shown in FIG. 5, the radiator 36 is circulated by bypassing the radiator 36 via the outlet 32a.

At this time, since the cooling water stays in the water jacket 34 on the cylinder block side without being circulated, the temperature of the inner wall of the bore of the cylinder block 33 rises faster, so that the friction during warm-up is increased. Can be reduced. On the other hand, after warming up, when the cooling water passage 42 is closed by the thermostat valve 41 and the cooling water passage 44 is opened, as shown in FIG. 15, the water pump 35 passes through the cylinder head side water jacket 32. After that, the cooling water that has passed through the water jacket 34 on the cylinder block side can be radiated by the radiator 36 and then recirculated to the water jackets 32 and 34. Therefore, after warming up, it is possible to cool the cylinder head 31 and the cylinder block 33, respectively.

The configuration of FIG. 13 has an advantage over the configuration of FIG. 10 in that no valves other than the thermostat valve 41 are required.

[0012]

By the way, in such a cooling device for an internal combustion engine, the cooling water discharged from the water pump must flow into the water jacket on the cylinder head side. Must be installed on the cylinder head side. But,
As shown in FIG. 16, a cam drive sprocket 46, an intake manifold 47, and an exhaust manifold are provided above the engine 45.
48, etc., it is spatially difficult to install a water pump.

Further, for the cam driving sprocket 46,
If the water pump is to be installed on the opposite side in the camshaft direction, the water pump is laid out at the cylinder head end 50 above the joint between the engine 45 and the transmission 49. Therefore, the belt for driving the water pump cannot be shared with the belt 52 that drives auxiliary machines such as the alternator 51, and it is necessary to use an independent belt.
Improvements have been sought because they lead to higher manufacturing costs.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a cooling device for an internal combustion engine, which is capable of performing cooling control according to the warm-up state, at low cost.

[0015]

Therefore, according to the first aspect of the invention, in the cooling device for the internal combustion engine in which the water jacket for circulating the cooling water is formed in the cylinder head and the cylinder block, respectively, the discharge of the water pump Side is connected to the water jacket on the cylinder block side at one end in the cylinder row installation direction, and the water jacket on the cylinder block side and the water jacket on the cylinder head side are communicated with each other only on the one end side in the cylinder row installation direction. While forming cooling water outlets on the water jacket and the water jacket on the cylinder block side, respectively, on the end side opposite to the one end in the cylinder row installation direction,
A first cooling water path that connects the cooling water outlet of the cylinder head side water jacket to the suction side of the water pump by bypassing the radiator, and the cooling water outlet of the cylinder block side water jacket of the water pump through the radiator. A second cooling water passage connected to the suction side and a valve for opening and closing at least the second cooling water passage according to the cooling water temperature are provided.

According to the second aspect of the present invention, the communication portion between the water jacket on the cylinder head side and the water jacket on the cylinder block side is located closer to the connecting portion than the cylinder closest to the connecting portion on the discharge side of the water pump. In addition, it is provided along the circumferential shape of the cylinder. Further, in the invention according to claim 3, the communication portion between the water jacket on the cylinder head side and the water jacket on the cylinder block side is provided between the cylinder closest to the connection portion on the discharge side of the water pump and the cylinder adjacent to the cylinder. It is characterized by being provided in.

Further, in the invention according to claim 4, the communicating portion between the cylinder block side water jacket and the cylinder head side water jacket is. The head gasket interposed between the cylinder block and the cylinder head has a water hole formed only on one end side in the cylinder arrangement direction. Further, the invention according to claim 5 is characterized in that the cylinder block has an open deck structure in which the bore wall and the outer wall are not connected on the upper surface of the cylinder block.

Further, in the invention according to claim 6, a groove for communicating between a plurality of holes formed in the upper wall connecting the bore wall of the cylinder block and the outer wall on the upper surface of the cylinder block is provided on the upper surface of the upper wall. It is characterized by being provided.

[0019]

In the invention according to claim 1, the second valve is used.
When the cooling water path is closed, the cooling water flowing from the cylinder block side water jacket to the radiator is blocked without being circulated. Therefore, the cooling water that has entered the water jacket on the cylinder block side from the water pump flows into the water jacket on the cylinder head side through the communicating portion between the water jacket on the cylinder block side and the water jacket on the cylinder head side, and then enters the water jacket on the cylinder head side. Only the first cooling water path, which bypasses the radiator and returns to the water pump, is circulated from the formed outlet.

On the other hand, when the valve is opened, the cooling water that has entered the water jacket on the cylinder block side flows through the first cooling water path and the outlet formed in the water jacket on the cylinder block side via the radiator. It is circulated separately as one that flows through the second cooling water path that returns to the water pump. While control according to such a warm-up state is possible, the discharge side of the water pump need only be connected to the cylinder block side, so the water pump can be laid out on the cylinder block side.

Further, in the invention according to claim 2, when the cooling water circulates only in the first cooling water path during warm-up, as soon as the cooling water flows from the discharge port of the water pump into the water jacket on the cylinder block side. Since the water flows to the communication portion that leads to the water jacket on the cylinder head side, the flow range of the cooling water in the water jacket on the cylinder block side is minimized and the warm-up effect is improved.

Further, in the invention according to claim 3, when the cooling water circulates only in the first cooling water path during warm-up, when the cooling water flows into the cylinder block side water jacket from the discharge port of the water pump, After passing through the bore wall of the cylinder closest to the discharge port of the pump, the fluid flows to the communicating portion that exits to the water jacket on the cylinder head side, resulting in a smooth flow and reduced water resistance.

Further, in the invention according to claim 4, the communicating portion between the water jacket on the cylinder head side and the water jacket on the cylinder block side can be obtained only by replacing the head gasket without making a large-scale design change of the cylinder head or the cylinder block. The position of can be easily changed. Further, in the invention according to claim 5, since the cylinder block has an open deck structure and the upper side of the water jacket is defined by a flat gasket, the air mixed in the cooling water is collected in the upper part of the cylinder block side water jacket. Without passing through the water jacket from the cylinder block side to the water jacket from the cylinder head side.

That is, in the conventional cylinder block having the closed deck structure in which the cylinder block bore wall and the outer wall are connected by the upper wall on the upper surface of the cylinder block, the upper wall of the water jacket on the cylinder block side is the middle wall during casting. There is a problem that the cooling efficiency of the upper portion of the cylinder block is deteriorated due to the presence of the child sand removal hole, the upper portion of which is blocked by the gasket, and the air mixed in the cooling water is accumulated therein. The invention can be solved.

Further, in the invention according to claim 6, the air mixed in the cooling water passes through a plurality of core sand removing holes formed in the upper wall of the cylinder block side water jacket, and the air of the cylinder block side water jacket is removed. Through the groove provided on the upper surface of the upper wall, the water is guided from the cylinder block side water jacket to the communication part to the cylinder head side water jacket, and then escapes to the cylinder head side water jacket. With this, the cooling efficiency of the upper portion of the cylinder block can be improved as in the invention according to claim 5.

[0026]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a system configuration diagram showing an embodiment of a two-system cooling device for an internal combustion engine according to the present invention. Water jacket 2 for circulating cooling water in cylinder head 1
And a water jacket 4 for circulating cooling water in the cylinder block 3.

The discharge side of the water pump 5 is connected only to the cylinder block side water jacket 4 at one end in the cylinder row installation direction, and the cylinder block side water jacket 4 and the cylinder head side water jacket 2 are connected in the cylinder row installation direction. The communication portion 6 communicates only with the one end portion side. The cylinder head side water jacket 2 and the cylinder block side water jacket 4 are provided with cooling water outlets 2a and 4a, respectively, on the end side opposite to the one end in the cylinder array direction.

The outlet 2a formed in the water jacket 2 on the cylinder head side bypasses the radiator 8 by the cooling water passage 7 and is connected to the suction side of the water pump 5 via the thermostat valve 9 (first cooling water path). ). The outlet 4a formed in the water jacket 4 on the cylinder block side is connected to the suction side of the water pump 5 via the radiator 8 by the cooling water passage 10 and further via the thermostat valve 9 (second cooling). Water path).

In the above construction, the thermostat valve 9 provided at the confluence of the cooling water passage 7 and the cooling water passage 10 is a valve having a simple structure which is opened and closed by a heat sensitive member sensitive to cooling water. When the cooling water temperature is low (during warming up), the cooling water passage 10 is closed to block the flow of cooling water from the radiator 8 to the water pump 5 side, and when the cooling water temperature rises (after warming up), The cooling water passage 10 is opened to circulate the cooling water from the radiator 8 to the water pump 5 side.

That is, the thermostat valve 9 opens and closes the cooling water passage 10 in accordance with the cooling water temperature to interrupt the circulation of the cooling water in the second cooling water passage. When the circulation of the cooling water through the cooling water passage 10 is blocked by the thermostat valve 9 during warm-up, the circulation path from the cylinder block side water jacket 4 to the water pump 5 via the radiator 8 is cut off. The cooling water that has entered the cylinder head side water jacket 2 from the water pump 5 through the cylinder block side water jacket 4 and the communication portion 6 bypasses the radiator 8 via the outlet 2a, as shown in FIG. It will be circulated to the pump 5.

At this time, since the cooling water stays in the water jacket 4 on the cylinder block side without being circulated, the temperature of the inner wall of the bore of the block rises faster, and thus the friction during warming up can be reduced. Of course, the configuration shown in FIG. 1 does not require any valve other than the thermostat valve 9, and the thermostat valve 9
Because the flow of cooling water from the cylinder block side water jacket 4 to the radiator 8 is blocked upstream of the water pump 5, the movement of the cooling water in the cylinder block side water jacket 4 changes from the discharge side of the water pump 5 to the cylinder block side. Since only the portion that enters the water jacket 4 and flows to the cylinder head side water jacket 2 via the communication portion 6 is stopped and the circulation of the cooling water is stopped in almost all places in the cylinder block side water jacket 4, a high bore inner wall temperature is maintained. Can be stably maintained.

On the other hand, after warming up, the thermostat valve 9
When the cooling water passage 10 is opened by the cooling water passage, the cooling water can be circulated also in the second cooling water passage returning from the water jacket 4 on the cylinder block side to the water pump 5 via the radiator 8 as shown in FIG. , Water pump 5 to water jacket 4 on the cylinder block side
The cooling water that has passed through can be radiated by the radiator 8 and then recirculated to the water jackets 2 and 4. Therefore, after warming up, it is possible to cool the cylinder head 1 and the cylinder block 3, respectively.

Although the thermostat valve 9 does not directly detect the water temperature in the cylinder block side water jacket 4, the relationship between the water temperature in the cylinder head side water jacket 2 and the water temperature in the cylinder block side water jacket 4 is previously determined. If checked, it is possible to control the water temperature in the water jacket 4 on the cylinder block side to a predetermined value. For example, when the target of the water temperature in the water jacket 4 on the cylinder block side is 90 ° C.,
Water temperature in the water jacket 2 on the cylinder head side is 80 ℃
If there is a correlation that the cylinder block side is 90 ° C. at the time of, the thermostat valve 9 may be opened at 80 ° C. (the cooling water passage 11 is opened).

In this embodiment, the thermostat valve 9 is provided at the confluence of the cooling water passages 7 and 10. However, the thermostat valve 11 is provided at the outlet 4a of the water jacket 4 on the cylinder block side and the inlet of the radiator 6. 6
A structure as shown in FIG. 4 may be used, which is interposed in the cooling water passage 10 between a and a. In this case, when the cooling water passage 10 is closed by the thermostat valve 11 during warm-up, the outlet of the cooling water that has entered the cylinder block side water jacket 4 is blocked, so that the circulation of the cooling water in the second cooling water passage is prevented. Be stopped. And water pump 5
The cooling water that has entered the cylinder block side water jacket 4 enters the cylinder head side water jacket 2 through the communication portion 6 and is circulated in the first cooling water path.

On the other hand, in the structure shown in FIG. 4, since the cooling water passage 10 is opened by the thermostat valve 11 after warming up, the water jacket 4 on the cylinder block side is opened.
The cooling water that has entered is divided into one that flows to the first cooling water path and one that flows to the second cooling water path via the communication portion 6, and is circulated in both cooling water paths. in this case,
Since the water temperature sensed by the thermostat valve 11 is close to the water temperature in the water jacket 4 on the cylinder block side,
The inner wall temperature of the bore of the cylinder block 3 can be controlled more accurately.

Further, in FIG. 4, if the thermostat valve 11 is provided with a small hole that allows a minute flow rate even when the thermostat valve 11 is closed and a slight amount of cooling water is circulated even when the thermostat valve 11 is closed, the cylinder block temperature can be detected. Can be done more accurately. Further, although the thermostat valve is used as the valve in the present embodiment, an electromagnetic valve or the like whose opening / closing is controlled based on the cooling water temperature detected by the cooling water temperature sensor may be used.

FIG. 5A is a plan view of a cylinder block 3 showing a more specific embodiment of the communicating portion 6 between the cylinder head side water jacket 2 and the cylinder block side water jacket 4 in the present invention. 5B shows the water jacket 2 on the cylinder head side and the water jacket 4 on the cylinder block side, which are taken along line A- in FIG. 5A.
FIG.

A water jacket 2 for circulating cooling water in the cylinder head 1 and a water jacket 4 for circulating cooling water in the cylinder block 3 are formed respectively. The cylinder head 1 and the cylinder block 3 are joined together via a head gasket 12, and the water jackets 2 and 4 are communicated with each other with a water hole formed in the head gasket 12 as a communication portion 6.

The cylinder block 3 of the present embodiment has an open deck structure in which the cylinder block bore wall 13 and the outer wall 14 are not connected on the upper surface of the cylinder block 3, and the cylinder block side water jacket 4 has a flat head gasket on the upper side. It is defined by twelve. As shown in the reference example of FIG. 6, in the cylinder block having the normal closed deck structure, the cylinder block bore wall and the outer wall are connected by the upper wall 15 on the upper surface of the cylinder block 3. In this case, the upper wall 15 of the water jacket 4 on the cylinder block side has a core sand removing hole 16 at the time of casting, and if the head gasket 12 blocks the upper part,
The air mixed in the cooling water accumulates there, and the cooling efficiency of the upper surface portion of the cylinder block 3 deteriorates.

In the open deck structure as shown in FIG. 5 of this embodiment, since the upper side of the water jacket 4 on the cylinder block side is defined by the flat gasket 12,
Since there is no place where the mixed air stays and passes through the communication portion 6 to the cylinder head side water jacket 2 together with the flow of the cooling water, the cooling efficiency of the upper surface portion of the cylinder block 3 is improved.

Further, as shown in FIG. 7, in the cylinder block having the closed deck structure, the groove 17 is formed on the upper surface of the upper wall 15.
By forming the core sand removing hole 16 and the communicating portion 6 to communicate with each other, the air accumulated in the core sand removing hole 16 can be discharged to the water jacket 2 on the cylinder head side, and the cylinder of the open deck structure can be formed. The same effect as in the case of blocks can be obtained.

FIG. 8 shows a water hole in the head gasket 12,
That is, it is a diagram showing the relationship between the position of the communication portion 6 and the flow of cooling water. In this embodiment, the water hole formed in the head gasket 12 is used as the communication part 6. As shown in FIG. 8 (A), when one end of the water pump 5 close to the connection portion with the discharge side is provided with the communication portion 6 along the circumferential shape of the cylinder 18 formed at the end, warming is performed. The flow of cooling water from the cylinder block side water jacket 4 to the cylinder head side water jacket 2 is as shown in FIG. 8 (B). In this case, the range in which the cooling water circulates in the cylinder block side water jacket 4 during warm-up is minimized, and the warm-up efficiency is improved.

Further, as shown in FIG. 9 (A), the communication portion 6
9 is provided between the cylinder 18 and the cylinder 19 adjacent thereto, as shown in FIG. 9 (B), the cylinder block side water jacket 4 widens the range of flow of cooling water during warm-up, and the warm-up efficiency is improved. Although it decreases, the bending angle becomes gentle when the cooling water flows into the water jacket on the cylinder head side, so that there is an advantage that the water flow resistance decreases.

[0044]

As described above, according to the first aspect of the present invention, since the cooling water flows only to the water jacket on the cylinder head side at the time of warming up, the effect of improving the warming up can be obtained. The passage of cooling water after the machine is a parallel flow of the first cooling water passage passing through the water jacket on the cylinder head side and the second cooling water passage passing through the water jacket on the cylinder block side and the radiator. The resistance is low, and the flow rate of the water pump alone can be reduced, which has the effect of reducing fuel consumption.

Further, since the water pump is attached to the cylinder block, the structure is simple, which is advantageous in terms of manufacturing cost. According to the second aspect of the invention, since the retention range of the cooling water in the cylinder block side water jacket is widened during warm-up, the warm-up efficiency is improved.

According to the third aspect of the invention, the flow of the cooling water from the water jacket on the cylinder block side to the water jacket on the cylinder head side becomes smooth, so that the water flow resistance can be kept low and the load on the water pump can be reduced. There is an effect of doing. According to the invention of claim 4, the position of the communicating portion between the water jacket on the cylinder head side and the water jacket on the cylinder block side can be changed only by replacing the head gasket without making a large-scale design change of the cylinder head or the cylinder block. The effect is that it can be changed easily.

According to the fifth aspect of the invention, the air mixed in the cooling water can easily escape from the water jacket on the cylinder block side, and the cooling efficiency of the upper portion of the cylinder block can be increased. According to the invention of claim 6, even in a cylinder block having a closed deck structure in which the cylinder block bore wall and the outer wall are connected to each other on the upper surface of the cylinder block, the air mixed in the cooling water flows from the cylinder block side water jacket. There is an effect that it can be easily removed, and the cooling efficiency of the upper portion of the cylinder block can be increased.

[Brief description of drawings]

FIG. 1 is a system configuration diagram of an embodiment of the present invention.

FIG. 2 is a state diagram showing the flow of cooling water during warm-up in the above embodiment.

FIG. 3 is a state diagram showing the flow of cooling water after warm-up in the above embodiment.

FIG. 4 is a system configuration diagram when the thermostat valve is provided at another position in the same embodiment.

FIG. 5 is a plan view of a cylinder block portion and a sectional view of a cylinder block / cylinder head portion showing a more specific embodiment of the present invention.

FIG. 6 is a plan view of a cylinder block portion showing a reference example and a sectional view of a cylinder block / cylinder head portion.

FIG. 7 is a plan view of a cylinder block portion showing another embodiment and a sectional view of a cylinder block / cylinder head portion.

FIG. 8 is a diagram showing positions of water holes (communication portions) in the head gasket and water passages for cooling water.

FIG. 9 is a diagram showing a cooling water passage when water holes (communication portions) are provided at different positions.

FIG. 10 is a system configuration diagram showing a conventional cooling device.

11 is a state diagram showing the flow of cooling water during warm-up in the system of FIG.

FIG. 12 is a state diagram showing the flow of cooling water after warming up in the system of FIG. 9.

FIG. 13 is a system configuration diagram showing another example of a conventional cooling device.

14 is a state diagram showing the flow of cooling water during warm-up in the system of FIG.

15 is a state diagram showing the flow of cooling water after warming up in the system of FIG.

FIG. 16 is a front view and a side view showing a positional relationship between the water pump and the engine.

[Explanation of symbols]

 1 Cylinder head 2 Cylinder head side water jacket 3 Cylinder block 4 Cylinder block side water jacket 5 Water pump 6 Communication part 7 Cooling water passage 8 Radiator 9 Thermostat valve 10 Cooling water passage 11 Thermostat valve 12 Head gasket 13 Cylinder block bore wall 14 Cylinder block outer wall 15 Cylinder block upper wall 16 Core sand removing hole 17 Groove 18 Cylinder 19 Cylinder

Claims (6)

[Claims] 1. A cooling device for an internal combustion engine, wherein a water jacket for circulating cooling water is formed in each of a cylinder head and a cylinder block, wherein a discharge side of a water pump is located at a cylinder block side water jacket at one end in a cylinder row installation direction. The cylinder block side water jacket and the cylinder head side water jacket are connected only at the one end side in the cylinder row installation direction, and the cylinder head side water jacket and the cylinder block side water jacket are connected in the cylinder row direction. A cooling water outlet is formed on the end side opposite to the one end, and a cooling water outlet of the cylinder head side water jacket is connected to the suction side of the water pump bypassing the radiator. , Cylinder block side water jacket cooling A second cooling water path connecting the water outlet to the suction side of the water pump via the radiator; and a valve that opens and closes at least the second cooling water path in accordance with the cooling water temperature. Cooling device for internal combustion engine. 2. A peripheral shape of the cylinder, wherein a communication portion between the water jacket on the cylinder head side and the water jacket on the cylinder block side is located closer to the connection portion than a cylinder closest to the connection portion on the discharge side of the water pump. The cooling device for an internal combustion engine according to claim 1, wherein the cooling device is provided along the above. 3. A communication part between the water jacket on the cylinder head side and the water jacket on the cylinder block side is provided between a cylinder closest to a connection portion on the discharge side of the water pump and a cylinder adjacent to the cylinder. The cooling device for an internal combustion engine according to claim 1, wherein 4. A communicating portion between the water jacket on the cylinder block side and the water jacket on the cylinder head side is provided only on one end side in a cylinder row installation direction in a head gasket interposed between the cylinder block and the cylinder head. The cooling device for an internal combustion engine according to any one of claims 1 to 3, wherein the cooling device is formed by forming a water hole. 5. The cooling device for an internal combustion engine according to claim 4, wherein the cylinder block has an open deck structure in which the bore wall and the outer wall are not connected at the top surface of the cylinder block. 6. A groove is provided on the upper surface of the upper wall for communicating between a plurality of holes formed in the upper wall connecting the bore wall of the cylinder block and the outer wall on the upper surface of the cylinder block. The cooling device for an internal combustion engine according to claim 4.