JPH08326534A - Cooling device for internal combustion engine - Google Patents

Abstract

PURPOSE: To positively stop the flow of cooling water in a water jacket on the cylinder block side during warming up so as to be able to set the bore internal wall temperature high. CONSTITUTION: During warming up, a radiator 6 is detoured to circulate cooling water only in a water jacket on the cylinder head 1 side. The water hole 21a of a head gasket 21 is opened only in a cylinder part to be the lowermost reaches in a cooling water circulating path in the water jacket 2 so as to prevent the generation of cooling water flow in a water jacket 4 on the cylinder block 3 side being influenced by the circulation of cooling water in the water jacket 2. After warming up, cooling water fed to the water jacket 2 is fed to the water jacket 4 side through the water hole 21a so as to circulate cooling water in both water jackets 2, 4.

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 type cooling device capable of setting a high inner wall temperature of a bore of a cylinder block during warm-up operation.

[0002]

2. Description of the Related Art A conventional cooling device for an internal combustion engine is shown in FIG.
There was a configuration as shown in. In FIG. 11, 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 so as to communicate with each other.

The discharge side of the water pump 5 is connected to the block side water jacket 4, and the cooling water in the water jacket 4 passes through the water jacket 4 and then enters the head side water jacket 2.
A thermostat valve 9 is provided at the outlet of the water jacket 2, and the thermostat valve 9 bypasses the passage 6 for circulating cooling water to the water pump 5 via the radiator 6 and the radiator 6. Switching with the passage 8 for circulating the cooling water to the water pump 5 is performed.

The thermostat valve 9 is a valve that opens and closes in response to the temperature of the cooling water. During warming up (cooling down), the passage 7 is closed while the passage 8 is opened so that the radiator of cooling water is opened. The circulation to 6 is cut off, the radiator 6 is bypassed, and the cooling water is circulated to accelerate the warm-up. On the other hand, after warming up, while closing the passage 8,
By opening the passage 7, the water jacket 4, 2
The cooling water that has passed through is circulated in the radiator 6 so that the radiator 6 radiates heat.

In the above conventional cooling device, the cooling water is circulated to the water jacket on the head side through the water jacket on the cylinder block, and also acts as an air vent when the cooling water is injected into the water jacket on the cylinder block side. Therefore, as shown in FIG. 12, a water hole 21a is provided for each cylinder in the head gasket 21, and both water jackets 2, 2 are formed by the water hole 21a.
I am trying to make 4 communicate.

The water hole 21a shows a hole through which cooling water actually passes. For example, a cylinder of the closed deck specification in which the cylinder block bore wall and the cylinder block outer wall are connected in the vicinity of the top deck surface. When a block is used, a water hole 21a is opened in the head gasket 21 corresponding to a communication hole that is opened in each cylinder on the top deck surface and communicates with a water jacket.
When using an open deck specification cylinder block in which the cylinder block bore wall and the cylinder block outer wall are separated from each other near the top deck surface, use the head gasket 21 corresponding to the open end of the water jacket.
A water hole 21a is appropriately opened for each cylinder.

In FIG. 12, 21b is a head bolt through hole, 21c is an oil hole, and 21d is a bore hole.

[0008]

By the way, according to the above-described conventional cooling device, warm-up can be accelerated by circulating cooling water by bypassing the radiator during warm-up, but even during warm-up. Since the cooling water is circulated in both the water jackets of the cylinder block and the cylinder head, the inner wall temperature of the bore of the cylinder block cannot be sufficiently raised, and the friction reduction during warm-up cannot be sufficiently achieved. was there.

Such a problem is that at least an inlet for directly supplying cooling water to the water jacket of the cylinder head without using the water jacket of the cylinder block and an outlet for directly discharging the cooling water. Is provided, and at the time of warming up, the circulation of the cooling water in the water jacket of the cylinder block is stopped, and the cooling water is circulated only in the water jacket of the cylinder head.

However, even if an attempt is made to circulate the cooling water only on the cylinder head side during warming up to sufficiently raise the inner wall temperature of the bore, as described above, if the head gasket has a water hole for each cylinder, both water The cooling water supplied to the cylinder head side due to the pressure difference between the jackets flows into the block side through the water holes to generate a cooling water flow in the water jacket of the cylinder block, and the cooling water on the cylinder block side is generated. It was difficult to effectively stop the circulation.

The present invention has been made in view of the above problems, and by stably stopping the flow of the cooling water in the water jacket on the cylinder block side during warm-up, a high block bore inner wall temperature during warm-up is ensured. It is an object of the present invention to provide a cooling device that can maintain

[0012]

Therefore, in the cooling device for an internal combustion engine according to the invention of claim 1, water jackets for circulating cooling water are formed in the cylinder head and the cylinder block of the internal combustion engine so as to communicate with each other. While forming the cooling water outlet in each water jacket, connect only the water jacket on the cylinder head side to the discharge side of the water pump,
The outlet of the water jacket on the cylinder head side forms a first cooling water passage that bypasses the radiator and is connected to the water pump, while the outlet of the water jacket on the cylinder block side connects to the water pump via the radiator. A second cooling water passage to be connected is formed, and a valve for opening and closing at least the second cooling water passage in accordance with the cooling water temperature is provided, and a water jacket and a cylinder block on the cylinder head side in the head gasket. The water hole communicating with the water jacket on the side is formed only in the cylinder portion on the most downstream side in the cooling water circulation path in the water jacket on the cylinder head side.

In a cooling device for an internal combustion engine according to a second aspect of the present invention, the cylinder block has an open deck specification in which a cylinder block bore wall and a cylinder block outer wall are separated from each other in the vicinity of the top deck surface. . In the cooling device for an internal combustion engine according to the invention of claim 3, the cylinder block has a closed deck specification in which a cylinder block bore portion wall and a cylinder block outer wall are connected in the vicinity of the top deck surface, and the cylinder block A communication groove is formed on the top deck surface so as to connect the communication holes that open on the top deck surface to each other.

[0014]

According to the cooling device for an internal combustion engine of the first aspect of the invention, when the second cooling water passage is closed by the valve, the cooling water passes through the water jacket on the cylinder head side and then enters the water jacket on the cylinder block side. Water is dammed without circulation. Therefore, the cooling water that has passed through the water jacket on the cylinder head side is circulated by the water pump bypassing the radiator from the outlet formed on the water jacket on the head side. On the other hand, when the second cooling water passage is opened by the valve, the cooling water that has passed through the water jacket on the cylinder head side and then enters the water jacket on the cylinder block side is circulated to the water pump via the radiator. become.

Here, as described above, the water hole of the head gasket is provided only in the cylinder portion on the most downstream side in the cooling water circulation path in the water jacket on the cylinder head side, and is opened on the top deck surface of the cylinder block. Regardless of the opening that communicates with the water jacket, the communication path of the cooling water between the water jackets is limited to the cylinder portion that is the most downstream side in the cooling water circulation path.

As a result, while ensuring the communication passage and the air vent passage for the cooling water between the head side and the block side, the cooling water is circulated in the water jacket on the head side during warm-up, and the cooling water on the block side is affected. It is possible to suppress the generation of cooling water flow in the water jacket as much as possible. In the cooling device for an internal combustion engine according to the invention of claim 2,
The head block side and the block side other than the cylinder portion which is the most downstream side in the cooling water circulation path are configured by using the cylinder block of the open deck specification in which the cylinder block bore wall and the cylinder block outer wall are separated from each other near the top deck surface. The head gasket is used to block the flow of cooling water between and.

In the cooling device for an internal combustion engine according to the third aspect of the present invention, even if the cylinder block of the closed deck specification in which the cylinder block bore portion wall and the cylinder block outer wall are connected in the vicinity of the top deck surface, generally, Since it is necessary to open a communication hole that communicates with the water jacket for each cylinder on the top deck surface as a hole for the sand in casting, the flow of cooling water through this communication hole should be the most downstream in the cooling water circulation path. Except for the cylinder portion on the side, the head gasket is used for blocking.

Further, since the communication groove for communicating the communication holes opened on the top deck surface of the cylinder block with each other is formed in the top deck surface, the passage formed between the communication groove and the head gasket is formed in each cylinder. It works as air bleeding for each, and even if the communication path between the head side and the block side is limited by the closed deck specification, good air bleeding is performed.

[0019]

Embodiments of the present invention will be described below. Figure 1
It is a system configuration diagram showing a first embodiment of a cooling device for an internal combustion engine according to the present invention. In FIG. 1, a water jacket 2 for circulating cooling water in a cylinder head 1 and a water jacket 4 for circulating cooling water in a cylinder block 3 are respectively formed, and the water jackets 2 and 4 are head gaskets 21. They are communicated with each other through a water hole 21a opened in the.

The cylinder block 3 has a closed deck specification in which the cylinder block bore wall and the cylinder block outer wall are connected in the vicinity of the top deck surface. A communication hole 3a, which communicates with the water jacket 4 for each cylinder, is opened in the top deck surface 3b. The water hole 21a of the head gasket 21 has a cooling water circulation in the water jacket 2 of the cylinder head 1 as described later. The cylinder part on the most downstream side in the route,
In other words, the water hole is opened only in the communicating hole 3a of the cylinder portion closest to the outlet 2a, which will be described later, so that both water jackets communicate with each other only in the cylinder portion (see FIG. 2). Therefore, the communication hole 3a provided in the portion other than the cylinder portion does not function as a passage for the cooling water.

In FIG. 2, 21b is a head bolt through hole, 21c is an oil hole, and 21d is a bore hole. The outlet 2a formed in the water jacket 2 on the head side bypasses the radiator 6 via the thermostat valve 9 and is connected to the suction side of the water pump 5 by a cooling water passage 11 (first cooling water passage). The discharge side of is connected only to the water jacket 2 on the head side.

The outlet 4a formed in the water jacket 4 on the block side is the inlet side 6a of the radiator 6.
Is connected via a cooling water passage 12. An outlet side 6b of the radiator 6 is connected to a thermostat valve 9 via a cooling water passage 13 and joins with the cooling water passage 11 to be connected to the water pump 5. The cooling water passage 12,
13 constitutes the second cooling water passage of this embodiment.

In this structure, the thermostat valve 9 provided at the confluence of the cooling water passage 13 and the cooling water passage 11 is a valve that opens and closes by a heat sensitive member that is sensitive to the cooling water. When the temperature of the cooling water is low (during warm-up), the cooling water passage 11 is opened and the cooling water passage 13 is closed to block the flow of the cooling water from the radiator 6 to the water pump 5 to cool the cooling water. When the water temperature rises (after warming up), the cooling water passage 11 is closed and the cooling water passage 13 is opened to circulate the cooling water from the radiator 6 to the water pump 5 side.

That is, the thermostat valve 9 selectively opens either the cooling water passage 11 (first cooling water passage) or the cooling water passage 13 in accordance with the cooling water temperature, so that only one of the passages is opened. It is connected to the water pump 5 and switches between a cooling water circulation path that bypasses the radiator 6 and a cooling water circulation path that passes through the radiator 6. When the circulation of the cooling water through the cooling water passage 13 is blocked by the thermostat valve 9 during warm-up, the circulation path from the water jacket 4 on the block side to the water pump 5 via the radiator 6 is cut off. The cooling water that has entered the water jacket 2 on the head side from the water pump 5 is discharged from the outlet 2 as shown in FIG.
It is circulated to the water pump 5 by bypassing the radiator 6 via a.

At this time, since the cooling water stays in the water jacket 4 on the block side without being circulated, the temperature of the inner wall of the bore of the block rises quickly.
As a result, friction during warm-up can be reduced. However, in the first embodiment, no valve other than the thermostat valve 9 is required, and the cooling water that has entered the block-side water jacket 4 only by the action of the thermostat valve 9 is provided on the upstream side of the water pump 5. Since the damming is stopped, the circulation of the cooling water in the water jacket 4 can be reliably stopped, and a high bore wall temperature can be stably maintained.

Further, as described above, since the path for connecting the water jackets 2 and 4 is provided only in the cylinder portion on the most downstream side of the cooling water circulation path in the water jacket 2, only in the water jacket 2 on the head side. When circulating the cooling water, it is possible to prevent the cooling water from entering the side of the water jacket 4 from the side of the water jacket 2 due to the pressure difference between the water jackets 2 and 4 and causing a flow of the cooling water in the water jacket 4. it can.

For example, the water hole 21a of the head gasket 21
However, when the cooling water is circulated only in the water jacket 2 on the head side, as shown in FIG. 4, when the cooling water is circulated only in the water jacket 2, The cooling water enters the water jacket 4 side from the cylinder portion particularly near the water pump 5 due to the pressure difference between the water pumps 4 and causes a flow of the cooling water in the water jacket 4, but at the outlet 2a. Water hole only in the closest cylinder part
By providing 21a and communicating both water jackets 2 and 4 only in this part, it is possible to maximally prevent the flow of cooling water in the water jacket 4 due to the circulation of cooling water in the water jacket 2. . Therefore, the high inner wall temperature of the bore can be maintained more stably.

That is, if the circulation of the cooling water in the water jacket 4 is stopped at the time of warm-up as in the first embodiment, the radiator is bypassed but the water jackets 2 and 4 are cooled at the time of warm-up. Compared to a cooling device that circulates water, the inner wall temperature of the bore can be set higher, and the route for connecting the water jackets 2 and 4 is limited to the most downstream side of the circulation route on the head side by the water hole 21a of the head gasket 21. By doing so, the inner wall temperature of the bore can be set higher (see FIG. 5).

On the other hand, after warming up, the thermostat valve 9
When the cooling water passage 11 is closed and the cooling water passage 13 is opened by, the cooling water can be circulated from the water jacket 4 side to the water pump 5 via the radiator 6 as shown in FIG. After passing through the water jacket 2 on the head side from 5, the water hole
The cooling water supplied to the block side via 21 and passed through the water jacket 4 can be recirculated to the water jackets 2 and 4 after radiating heat in the radiator 6. 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 block-side water jacket 4, the relationship between the water temperature in the head-side water jacket 2 and the water temperature in the block-side water jacket 4 is previously determined. If checked, the water temperature in the water jacket 4 on the block side can be controlled to a predetermined value. For example, when the target of the water temperature in the water jacket 4 on the block side is 90 ° C., and when the water temperature in the water jacket 2 on the head side is 80 ° C., the water temperature in the block side is 90 ° C.
If the correlation is
The characteristic is that it opens at 80 ° C. (the state in which the cooling water passage 13 is open).

In the first embodiment shown in FIG. 1, the thermostat valve 9 is provided at the confluence of the cooling water passages 11 and 13, and either one of the passages and the water pump 5 is connected. The thermostat valve 14 may be arranged in the cooling water passage 12 between the outlet 4a of the water jacket 4 on the block side and the inlet 6a of the radiator 6. In this case, the thermostat valve 14
Suffices as long as the opening / closing operation is performed such that the cooling water passage 12 is closed at low temperature and opened at high temperature in response to the cooling water temperature. The valve structure is simpler than that of the first embodiment. You can

The thermostat valve 9 may be replaced with an electromagnetic valve, and the electromagnetic valve may be electronically controlled based on the detection result of the water temperature sensor. By the way, in the first embodiment, the cylinder block 3 has the closed deck specification in which the cylinder block bore wall and the cylinder block outer wall are connected in the vicinity of the top deck surface. However, as shown in FIG. An open deck specification in which the cylinder block bore wall and the cylinder block outer wall are separated from each other in the vicinity of the surface may be adopted.

Also in this case, as in the first embodiment, the water hole 21a of the head gasket 21 is opened only in the cylinder portion on the most downstream side of the cooling water circulation path on the head side, so that the water jacket is warmed up. It is possible to effectively suppress the generation of the flow of cooling water in the inside of No. 4, so that the inner wall temperature of the bore can be set high. Furthermore, if it is an open deck specification, the head gasket with a flat upper end surface of the water jacket 4
Since it is formed by 21, no air pocket is generated, and
As shown in FIG. 5, when the cooling water is injected into the water jacket 4, all the air can be extracted from the water hole 21a. Therefore, it is possible to prevent the cooling performance of the upper portion of the block from being deteriorated due to the remaining air.

On the other hand, in the closed-deck type cylinder block of the first embodiment, as shown in FIG. 9, the communication hole 3a closed by the head gasket 21 serves as an air reservoir to cool the inside of the water jacket 4. When injecting water, air may accumulate in the air reservoir portion. However, even in the case of using the closed-deck type cylinder block as in the first embodiment, FIG.
With the configuration as shown in the third embodiment shown in Fig. 3, it is possible to improve the air bleeding performance, and the air bleeding is performed while using the cylinder block of the closed deck specification in which the surface rigidity of the top deck is superior to that of the open deck specification. It is possible to avoid the deterioration of the cooling performance due to the failure of.

In the third embodiment shown in FIG. 10, the top deck surface 3 of the cylinder block 3 is different from that of the first embodiment.
The only difference is that a communication groove 3c that allows the communication hole 3a to communicate with each other is formed in the groove b. With this configuration, when the cooling water is injected into the water jacket 4, the air that has entered the communication hole 3a closed by the head gasket 21 can move toward the water hole 21a through the communication groove 3c. Therefore, the communication hole 3a can be prevented from becoming an air pocket.

Even if the communication groove 3c is provided as described above, the communication path of the cooling water from the head side is limited to the cylinder portion near the outlet 2a, so that the cooling water circulates on the head side during warm-up. It is the same as in the first embodiment that it is possible to avoid the flow of cooling water on the block side due to the influence of.

[0037]

As described above, according to the cooling device for an internal combustion engine according to the first aspect of the present invention, the circulation of the cooling water in the water jacket on the block side can be stopped at the time of warming up. It is possible to prevent the flow of cooling water in the water jacket on the block side due to the circulation of cooling water on the head side, so set the bore inner wall temperature of the cylinder block to a stable high value,
This has the effect of effectively reducing friction during warm-up.

According to the cooling device for an internal combustion engine according to the second aspect of the present invention, in the engine using the cylinder block of the open deck specification, the inner wall temperature of the bore can be stably set high at the time of warming up, and the open deck specification The cylinder block has an effect that even if the communication passage between the water jackets is limited, air can be satisfactorily removed when the cooling water is injected into the block side.

According to the cooling device for an internal combustion engine according to the third aspect of the present invention, in an engine using a closed deck specification cylinder block excellent in surface rigidity of the top deck,
The inner wall temperature of the bore can be set to a stable high value during warm-up, and even if the head gasket blocks the communication hole that opens to the top deck surface of the cylinder block and communicates with the water jacket, the cooling water to the block side There is an effect that air can be satisfactorily discharged by avoiding the accumulation of air in the communication hole portion at the time of injection.

[Brief description of drawings]

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

FIG. 2 is a perspective view showing a top deck surface of a cylinder block and a head gasket in the first embodiment.

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

FIG. 4 is a state diagram showing the flow of cooling water when a water hole is provided in the head gasket for each cylinder.

FIG. 5 is a diagram showing a correlation between an elapsed time after starting and a block wall temperature.

FIG. 6 is a state diagram showing the flow of cooling water after warming up in the first embodiment.

FIG. 7 is a perspective view showing a top deck surface of a cylinder block and a head gasket in a second embodiment.

8A and 8B are diagrams showing a state of air venting in the second embodiment, in which FIG. 8A is a vertical sectional view of a block and FIG. 8B is a top view of the block.

9A and 9B are diagrams showing a state of air venting in the first embodiment, in which FIG. 9A is a vertical sectional view of the block and FIG. 9B is a top view of the block.

10A and 10B are diagrams showing a state of air venting in the third embodiment, in which FIG. 10A is a vertical sectional view of the block and FIG.

FIG. 11 is a system configuration diagram showing a conventional cooling device.

FIG. 12 is a plan view showing a conventional gasket.

[Explanation of symbols]

 1 cylinder head 2 water jacket 3 cylinder block 3a communication hole 3b top deck surface 3c communication groove 4 water jacket 5 water pump 6 radiator 9 thermostat valve 11, 12 cooling water passage 21 head gasket 21a water hole 21b head bolt through hole 21c oil hole 21d bore hole

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display area F02F 1/36 F02F 1/36 Z

Claims (3)

[Claims] 1. A cylinder head and a cylinder block of an internal combustion engine are respectively formed with water jackets for circulating cooling water so as to communicate with each other, and cooling water outlets are formed in the respective water jackets, while the water pump discharges the water. Side, only the water jacket on the cylinder head side is connected, and the outlet of the water jacket on the cylinder head side forms a first cooling water passage that bypasses the radiator and connects to the water pump, while A second cooling water passage for connecting the outlet of the water jacket to the water pump via the radiator is formed, and at least the valve for opening and closing the second cooling water passage according to the cooling water temperature is provided. Together with the head gasket to the cylinder. Of the internal combustion engine characterized in that a water hole for communicating the water jacket on the side of the cylinder with the water jacket on the side of the cylinder block is opened only in the cylinder portion on the most downstream side in the cooling water circulation path in the water jacket on the cylinder head side. Cooling system. 2. The cooling device for an internal combustion engine according to claim 1, wherein the cylinder block has an open deck specification in which a cylinder block bore wall and a cylinder block outer wall are separated from each other in the vicinity of the top deck surface. . 3. The cylinder block has a closed deck specification in which a cylinder block bore wall and a cylinder block outer wall are connected in the vicinity of the top deck surface, and a communication hole opened on the top deck surface of the cylinder block is provided. 2. The cooling device for an internal combustion engine according to claim 1, wherein a communication groove for communicating with each other is formed in a recess on the top deck surface.