JPH04347325A - Water cooler of engine - Google Patents

Abstract

PURPOSE:To prevent a piston from seizing or binding by contracting a cylinder as letting a lot of low temperature cooling water in a radiator flow into a cylinder jacket at the time of imposing a suddent load on an engine immediately after start-up. CONSTITUTION:Cooling water flows into a head jacket 5 from a cylinder jacket 3 by way of a water hole 4. A passage contracting thermosensitive working valve 7 is installed in this water hole 4. This working valve 7 operates at a time when temperature in this cooling water passing through the water hole 4 goes up to a passage contraction realeasing operation temperature T3 little higher than a seizure occurring upper limit temperature Tg at the time of sudden load immediately after engine starting, thereby expanding a passage sectional area S of the water hole 4 up to the reference sectional area Sb from the contracted sectional area S1.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water cooling system for an engine.

0002

[Prerequisite Structure] The engine water cooling system of the present invention is predicated on having the following prerequisite structure, as shown in FIG. 4, for example. That is, the cooling water for the engine 1 is pumped and circulated by the water pump 2 from the cylinder jacket 3 in the order of the water hole 4, the head jacket 5, the radiator 6, and the cylinder jacket 3.

0003

[Prior art] In the above-mentioned premise structure, in the prior art,
The water hole 4 was formed to have a standard cross-sectional area Sb.

0004

[Problems to be Solved by the Invention] The above-mentioned prior art has the following problems. Since the water hole 4 is formed to have a standard cross-sectional area Sb, when the load output does not exceed the rating of the engine 1, the circulating amount of cooling water does not become excessive, and a reduction in combustion performance due to overcooling is prevented. ing. However, engine 1
When a load is suddenly applied immediately after a cold start, the piston 26 expands rapidly, while the thermostat 31 suddenly opens, and the low-temperature cooling water in the radiator 6 flows into the cylinder jacket 3, causing the cylinder 25 to contract. Therefore, the piston 26 may seize. Furthermore, during overload output, the amount of heat generated increases but the amount of circulating cooling water does not increase, so the engine 1 may overheat. An object of the present invention is to prevent the piston 26 from seizing when a load is suddenly applied immediately after a cold start of the engine, and to suppress overheating of the engine 1 when overloaded.

[0005]

[Means for Solving the Problems] In order to achieve the above object, the present invention adds the following improved structure to the above-mentioned premise structure, as shown in FIGS. 1 and 2, for example. That is, the temperature-sensitive operating valve 7 for passage reduction is provided in the water hole 4, and the operating temperature T3 for releasing the passage reduction of the temperature-sensitive operating valve 7 is equal to the seizure occurrence upper limit temperature T at the time of sudden load immediately after the cold start of the engine.
Set the temperature slightly higher than g. This temperature-sensitive operating valve 7 is temperature-sensing operated when the temperature of the cooling water passing through the water hole 4 rises to the operating temperature T3 for canceling passage reduction.
The passage cross-sectional area S of the water hole 4 is configured to be expanded from the reduced cross-sectional area S2 to the reference cross-sectional area Sb.

[0006]

[Operation] The present invention operates as follows. When the load output does not exceed the rating of the engine 1, the temperature of the cooling water passing through the water hole 4 is lower than the operating temperature T3 for canceling passage reduction. Therefore, when a load is suddenly applied immediately after a cold start of the engine 1, even if the thermostat 31 suddenly opens, the temperature T of the cooling water passing through the water hole 4 will be lower than the upper limit temperature at which seizure will occur under a sudden load immediately after a cold start of the engine. Tg (e.g. 50℃
), the temperature-sensitive operating valve 7 does not operate, so the passage cross-sectional area S of the water hole 4 remains the reduced cross-sectional area S2, and a large amount of low-temperature cooling water in the radiator 6 flows into the cylinder jacket 3. The cylinder 25 is not contracted and the piston 26 is prevented from seizing. On the other hand, when the engine outputs an overload, the temperature of the cooling water passing through the water holes 4 becomes higher than the operating temperature T3 for canceling passage reduction due to an increase in heat generation. Therefore, the temperature-sensitive operating valve 7 is temperature-sensingly operated to expand the passage cross-sectional area S of the water hole 4 from the reduced cross-sectional area S2 to the reference cross-sectional area Sb. As a result, the amount of circulating water is increased, the cooling capacity is increased, and overheating of the engine 1 is suppressed.

[0007]

[Effects of the Invention] Since the present invention is constructed and operates as described above, it has the following effects. When a load is suddenly applied immediately after a cold start of the engine, the passage cross-sectional area of the water hole remains the reduced cross-sectional area even if the thermostat suddenly opens, and a large amount of low-temperature cooling water in the radiator does not flow into the cylinder jacket. Since the cylinder 25 is not contracted, the piston 26 can be prevented from seizing. Furthermore, while the amount of heat generated increases when the engine outputs an overload, the amount of circulating water increases, the cooling capacity increases, and overheating of the engine 1 can be suppressed.

[0008]

Embodiments Hereinafter, embodiments of the present invention will be explained with reference to the drawings. Figure 1(A) is a plan view of the main parts of the engine head gasket.
1(B) is a sectional view taken along the line X-X in FIG. 1(A), FIG. 2 is a diagram showing the relationship between the cross-sectional area of water holes and cooling water temperature, FIG. 3 is a plan view of the head gasket, and FIG. is a schematic vertical cross-sectional view of the engine. In FIG. 4, the engine 1 includes a cylinder block 21 integrally formed above a crankcase 20, and a cylinder head 23 and a head cover 24 placed and fixed in order on the upper surface of the cylinder block 21 via a head gasket 22. , forming the engine body. Inside the cylinder block 21, there are a piston 26 that slides inside the cylinder 25, a connecting rod 28 that connects the piston 26 to a crankshaft 27, and others. Water holes 4 are provided in the inner walls of the cylinder block 21 and the cylinder head 23 to allow cooling water to flow from the cylinder jacket 3 to the head jacket 5.
It is connected through 2. Cooling water for the engine 1 is supplied from the cylinder jacket 3 to the water hole 4 by a water pump 2 driven from the crankshaft 27 via a belt 29 and a pulley 30.
- The head jacket 5, the radiator 6, and the cylinder jacket 3 are configured to be pumped and circulated in this order. Further, a thermostat 31 for detecting the temperature of the cooling water is provided in the middle of the cooling water circulation path, and the radiator 6 uses a radiator fan 32 to cool the high temperature cooling water. As shown in FIG. 3, the head gasket 22 includes each cylinder opening 22a, each push rod opening 22b, each water hole opening 22c and 22d, and each mounting bolt opening 22e. The required number of each is opened.

(First Embodiment) In the first embodiment of the present invention,
As shown in FIG. 1, for example, the water hole opening 22c of the head gasket 22, which is located in the middle of the water hole 4 that communicates the cylinder jacket 3 and head jacket 5, is formed of a shape memory alloy. A temperature-sensitive valve 7 for reducing the passageway is provided. The operating temperature T3 for releasing passage reduction of the temperature-sensitive operating valve 7 is set to a temperature slightly higher than the seizure occurrence upper limit temperature Tg during a sudden load immediately after a cold start of the engine. As shown in FIG. 2(A), this temperature-sensitive operating valve 7 is temperature-sensing operated when the temperature T of the cooling water passing through the water hole 4 rises to the operating temperature T3 for canceling passage reduction. The passage cross-sectional area S of the water hole 4 is configured to be expanded from the reduced cross-sectional area S2 to the reference cross-sectional area Sb. Therefore, the amount of circulating water increases, the cooling capacity increases, and overheating of the engine 1 is suppressed. Note that the temperature-sensitive operating valve 7 is not formed in the water hole opening 22d between the cylinders of the head gasket 22, and cooling water is constantly allowed to flow to promote cooling between the thermally severe cylinders.

(Second Embodiment) FIG. 5(A) is a plan view of essential parts of an engine head gasket, and FIG. 5(B) is a plan view of FIG. 5(A).
FIG. 2 is a sectional view taken along YY line. In the second embodiment of the present invention, the temperature-sensitive valve 7 is formed as shown in FIG. 5, for example. As shown in FIG. 2(B), when the temperature rises to T3, which is slightly higher than the seizure occurrence upper limit temperature Tg (for example, 50°C) immediately after a cold start of the engine, the upper operating valve 7a is activated by temperature sensing. Then, the passage cross-sectional area S of the water hole 4 is reduced to a reduced cross-sectional area S
2 to an enlarged cross-sectional area S1. If a load is suddenly applied immediately after engine 1 starts cold, thermostat 31
Even if the upper operating valve 7a opens suddenly, the upper operating valve 7a will not operate if the temperature T of the cooling water passing through the water hole 4 is below the seizure occurrence upper limit temperature Tg (for example, 50°C) at the time of a sudden load immediately after a cold start of the engine. , the passage cross-sectional area S of the water hole 4 remains the reduced cross-sectional area S2, and a large amount of low-temperature cooling water in the radiator 6 does not flow into the cylinder jacket 3 and contract the cylinder 25, preventing the piston 26 from seizing. prevent. If the temperature T of the cooling water passing through the water hole 4 is equal to or higher than the temperature T3, the upper operating valve 7a is temperature-sensing activated, and the passage cross-sectional area S of the water hole 4 is the reference cross-sectional area determined by the lower operating valve 7b. Becomes Sb. Furthermore, the cooling water temperature T1 just before overheating (
For example, at 110° C.), the lower operating valve 7b is temperature-sensing activated, and the passage cross-sectional area S of the water hole 4 is expanded from the standard cross-sectional area Sb to the enlarged cross-sectional area S.
Expand to 1. Therefore, the amount of circulating water increases, the cooling capacity increases, and overheating of the engine 1 is suppressed.

(Third Embodiment) FIG. 6(A) is a plan view of essential parts of an engine head gasket, and FIG. 6(B) is a plan view of FIG. 6(A).
It is a sectional view taken along the Z-Z line. In the third embodiment, the temperature-sensitive valve 7 is formed as shown in FIG. 6, for example. Figure 2(C)
As shown in , the temperature T is slightly higher than the upper limit temperature Tg (for example, 50°C) at which seizure occurs at the time of sudden load immediately after a cold start of the engine.
3, the upper operating valve 7a is activated by temperature sensing to expand the passage cross-sectional area S of the water hole 4 from the reduced cross-sectional area S2 to the reference cross-sectional area Sb. When a load is suddenly applied immediately after a cold start of the engine 1, the temperature T of the cooling water passing through the water hole 4 will be the upper limit temperature for seizure occurrence Tg (
For example, if the temperature is below 50°C, the upper operating valve 7a will not operate, so the passage cross-sectional area S of the water hole 4 will be reduced to a reduced cross-sectional area S2.
This prevents the low-temperature cooling water in the radiator 6 from flowing into the cylinder jacket 3 in large quantities and causing the cylinder 25 to contract, thereby preventing the piston 26 from seizing. Then, the valve opening temperature T2 of the conventional thermostat (for example, 82
℃), the lower operating valve 7b is temperature-sensing activated to expand the passage cross-sectional area S of the water hole 4 from the warm-up cross-sectional area Sd to the reference cross-sectional area Sb. When the cooling water temperature T after startup is lower than the valve opening temperature T2 of a conventional thermostat (e.g. 82°C), the upper operating valve 7a is operated, and the passage cross-sectional area S of the water hole 4 is changed by the lower operating valve 7b. Since the warm-up cross section is narrowed down to Sd, the amount of circulating water is small, and the temperature of the cooling water inside the engine rises rapidly and becomes uniform. As a result, it is no longer necessary to close the thermostat 31 and bypass the radiator 6 through the bypass passage 33 as in the conventional case, and the thermostat 3
1 can also be abolished. Furthermore, when the thermostat 31 opens, a large amount of low-temperature cooling water in the radiator 6 flows into the cylinder jacket 3, which may overcool a part of the otherwise homogenized engine interior, resulting in cooling loss. By eliminating the thermostat 31, overcooling of the engine in such a case can be eliminated, so cooling loss at room temperature is reduced. Furthermore, when the cooling water temperature T is equal to or higher than the valve opening temperature T2 (for example, 82° C.) of a conventional thermostat, the lower operating valve 7b is temperature-sensingly activated, and the passage cross-sectional area S of the water hole 4 is
Since the cooling water is expanded to the reference cross-sectional area Sb, the amount of circulating water is increased, the cooling capacity is increased, and overheating of the engine 1 is suppressed.

(Fourth Embodiment) FIG. 7(A) is a plan view of essential parts of an engine head gasket, and FIG. 7(B) is a plan view of FIG. 7(A).
It is a sectional view taken along the line V-V of FIG. In the fourth embodiment, the temperature-sensitive valve 7 is formed as shown in FIG. 7, for example. Figure 2(D)
As shown in , in the first stage, when the temperature rises to T3, which is slightly higher than the seizure occurrence upper limit temperature Tg (for example, 50°C) immediately after a cold start of the engine, the lower operating valve 7b
operates temperature-sensingly to reduce the passage cross-sectional area S of the water hole 4.
2 to an enlarged cross-sectional area S1. At this time, the middle operating valve 7c is not yet temperature-sensing operated, so the passage cross-sectional area S of the water hole 4 is the warm-up cross-sectional area Sd. When a load is suddenly applied immediately after a cold start of the engine 1, if the temperature T of the cooling water passing through the water hole 4 is below the upper limit temperature for seizure occurrence Tg (for example, 50 degrees Celsius) during a sudden load immediately after a cold start of the engine, the Side operating valve 7b
does not operate, the passage cross-sectional area S of the water hole 4 remains the reduced cross-sectional area S2, and a large amount of low-temperature cooling water in the radiator 6 does not flow into the cylinder jacket 3 and contract the cylinder 25, and the piston 26 prevent from burning. In the second stage, the valve opening temperature T2 (
For example, at 82° C.), the middle operating valve 7c is temperature-sensing activated, and the passage cross-sectional area S of the water hole 4 is changed from the warm-up cross-sectional area Sd to the enlarged cross-sectional area S.
Expand to 1. At this time, the upper operating valve 7a is not yet temperature-sensitively operated, so the passage cross-sectional area S of the water hole 4 is the reference cross-sectional area Sb. Therefore, when the cooling water temperature T after startup is lower than the valve opening temperature T2 of a conventional thermostat (for example, 82° C.), the middle operating valve 7c does not operate temperature-sensingly, and the passage cross-sectional area S of the water hole 4 is Since the cooling water is narrowed down to the warm-up cross-sectional area Sd, the circulating amount of the cooling water is small, and the cooling water temperature inside the engine rapidly rises and becomes uniform. As a result, as in the third embodiment described above, the thermostat 31 can be omitted, and engine overcooling can be eliminated, resulting in less cooling loss at room temperature. Furthermore, when the cooling water temperature T is higher than the valve opening temperature T2 (for example, 82° C.) of a conventional thermostat, the middle operating valve 7c is temperature-sensingly activated, so the passage cross-sectional area S of the water hole 4 is smaller than that of the upper operating valve. 7a is expanded to the reference cross-sectional area Sb. In the third stage, the cooling water temperature T1 (for example, 1
10°C), the upper operating valve 7a is temperature-sensing operated and the water hole 4 is opened.
The passage cross-sectional area S is expanded from the reference cross-sectional area Sb to the enlarged cross-sectional area S1. Therefore, the amount of circulating water increases, the cooling capacity increases, and overheating of the engine 1 is suppressed.

The temperature-sensitive operating valve 7 does not necessarily need to be formed in all the water hole openings 22c around the head gasket 22, and may be formed in some parts. or,
The temperature-sensitive operating valve 7 may be formed in the cylinder jacket 3 or the head jacket 5 instead of being formed in the water hole opening 22c or 22d of the head gasket 22. Furthermore, the temperature-sensitive operating valve 7 may be made of bimetal instead of being made of a shape memory alloy. It should be noted that the upper operating valve 7a and lower operating valve 7b in the above embodiment can be constructed by changing their positions.

[Brief explanation of drawings]

1 shows an embodiment of the present invention, FIG. 1(A) is a plan view of the main part of an engine head gasket, and FIG. 1(B) is a plan view of main parts of an engine head gasket;
) is a sectional view taken along line X-X.

FIG. 2 is a diagram showing an example of the present invention and showing the relationship between water hole cross-sectional area and cooling water temperature.

FIG. 3 shows an embodiment of the present invention and is a plan view of a head gasket.

FIG. 4 is a schematic vertical cross-sectional view of an engine, showing an embodiment of the present invention.

FIG. 5 shows another embodiment of the present invention, and FIG. 5(A) shows FIG.
A diagram corresponding to (A), Figure 5 (B) is Y-Y of Figure 5 (A)
It is a sectional view taken along the line.

FIG. 6 shows another embodiment of the present invention, and FIG. 6(A) shows FIG.
A diagram corresponding to (A), FIG. 6 (B) is a diagram corresponding to Z-Z of FIG. 6 (A)
It is a sectional view taken along the line.

FIG. 7 shows another embodiment of the present invention, and FIG. 7(A) shows FIG.
A diagram corresponding to (A), FIG. 7(B) is V-V of FIG. 7(A)
It is a sectional view taken along the line.

8 shows a conventional example, FIG. 8(A) is a diagram corresponding to FIG. 1(A), and FIG. 8(B) is a sectional view taken along the line WW in FIG. 8(A).

[Explanation of symbols]

1...Engine, 2...Water pump, 3...Cylinder jacket, 4...Water hole, 5...Head jacket, 6...Radiator,
7... Temperature-sensitive operating valve, T3... Operating temperature for releasing passage reduction, Tg
... Upper limit temperature for seizure occurrence, S... Passage cross-sectional area, S2... Reduced cross-sectional area, Sb... Reference cross-sectional area.

Claims (1)

[Claims] Claim 1: A water pump (
2) from the cylinder jacket (3) to the water hole (4)
- In an engine water cooling system configured to circulate under pressure in the order of head jacket (5), radiator (6), and cylinder jacket (3), a temperature-sensitive valve (7) for passage reduction is installed in the water hole (4). This temperature-sensitive valve (
The passage reduction release operating temperature (T3) in 7) is set to a temperature slightly higher than the seizure occurrence upper limit temperature (Tg) at the time of sudden load immediately after engine cold start, and this temperature-sensitive valve (7) When the temperature of the cooling water passing through the water hole (4) rises to the operating temperature (T3) for releasing the passage reduction, a temperature sensing operation is performed to reduce the passage cross-sectional area (S) of the water hole (4). Cross-sectional area (S
1) A water cooling device for an engine, characterized in that it is configured to expand from 1) to a standard cross-sectional area (Sb).