JPH04347326A - Water cooler multicylinder engine - Google Patents

Abstract

PURPOSE:To prevent any overheating from occurring by facilitating a flow of cooling water into an inmost space easier than this side space in a cylinder jacket before an engine is not approximated to an abnormal high temperature as well as increasing the extent of circulation of the cooling water when it is approximated to the abnormal high temperature after checking any thermal strain in a cylinder block. CONSTITUTION:A nearer side water hole 4a, leading to a head jacket 5 from a cylinder jacket 3, and an inmost side water hole 4b are installed in parallel, and a passage expanding thermosensitive working valve 7 is installed in the nearer side water hole 4a. This valve 7 operates at a time when a temperature in cooling water goes up to a passage expanding working temperature T1 little 1c than an abnormal high temperature area Th, expanding a passage sectional area S of the water hole 4a up to an expanded secttional area S1 from the reference sectional area. In this connection, the passage sectional area S of the inmost side water hole 4b is set to be larger in value than that of the reference sectional area Sb of this wayer hole 4a.

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 a multi-cylinder engine.

0002

[Prerequisite Structure] The water cooling system for a multi-cylinder engine of the present invention is predicated on having the following prerequisite structure, as shown in FIG. 4, for example. That is, the cooling water of the multi-cylinder engine 1 is pumped by the water pump 2 from the jacket inlet 8 to the cylinder jacket 3, water hole 4, head jacket 5, and jacket outlet 9.
・It is configured to circulate under pressure through the radiator 6 and the jacket inlet 8 in this order. And that water hole 4
This is made up of a front side water hole 4a located nearer to the jacket inlet 8 and the jacket outlet 9, and a back side water hole 4b located further away from the jacket inlet 8 and the jacket outlet 9, arranged in parallel.

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

[Problem to be solved by the invention] In the above conventional technology,
I have the following problem. 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, the cylinder jacket 3 and head jacket 5 at the rear of the engine 1
Because it is difficult for cooling water to flow into cylinder block 2,
The front of the 1 is relatively well cooled, but the rear is not so cool. Therefore, thermal distortion occurs in the cylinder block 21, and in severe cases, seizure of the cylinder 25 occurs. 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 suppress thermal distortion in the cylinder block 21 and seizure of the cylinder 25 and 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 operation valve 7 for passage expansion is provided in the water hole 4a on the front side, and the passage expansion operation temperature T of the temperature-sensor operation valve 7 is set at the front side water hole 4a.
1 is set to a temperature slightly lower than the abnormally high temperature region Th of the cooling water. This temperature-sensitive valve 7 is connected to the front water hole 4.
When the temperature of the cooling water passing through a rises to the operating temperature T1 for passage expansion, temperature-sensing operation is performed to change the passage cross-sectional area S of the front water hole 4a from the standard cross-sectional area Sb to the enlarged cross-sectional area. It is configured to expand to S1. Furthermore, the reference cross-sectional area Sb of the front water hole 4a is
The cross-sectional area S of the passage b is set to a large value.

[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 holes 4 is lower than the passage expansion operating temperature T1. At this time, the reference cross-sectional area S of the front water hole 4a
Since the passage cross-sectional area S of the rear water hole 4b is set to a larger value than b, the cooling water easily flows into the cylinder jacket 3 and head jacket 5 at the rear of the engine 1, and the cooling water flows easily between the front water hole 4a and the rear side. The amount of cooling water circulated through the water holes 4b is averaged, and the cylinder block 21 is cooled evenly, thereby suppressing the occurrence of thermal distortion. Also, the temperature-sensitive operating valve 7 is connected to the water hole 4 on the front side.
Since the cross-sectional area S of the passage a is maintained at the reference cross-sectional area Sb, the circulating amount of cooling water does not become excessive, and deterioration of combustion performance due to overcooling is prevented. 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 passage expansion operating temperature T1 due to an increase in the amount of heat generated. Therefore, the temperature-sensitive operating valve 7 is temperature-sensitively operated, and the water hole 4a on the front side is
The passage cross-sectional area S is changed from the standard cross-sectional area Sb to the enlarged cross-sectional area S1.
expand to. As a result, the amount of circulating water increases, the cooling capacity increases, 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. Cooling water easily flows into the cylinder jacket and head jacket at the rear of the engine, and the amount of circulating water is averaged, so that the cylinder block is cooled evenly and the occurrence of thermal distortion is suppressed. In addition, while the amount of heat generated increases when the engine outputs an overload, the temperature-sensitive operation of the temperature-sensitive valve increases the passage cross-sectional area of the water hole, increasing the amount of circulating water, thereby suppressing engine overheating. can do.

[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. The water hole 4 is formed by providing a front water hole 4a located near the jacket inlet 8 and a back water hole 4b located far from the jacket exit 9 in parallel. Become. Cooling water for the engine 1 is supplied from the crankshaft 27 to the cylinder jacket 3, water hole 4, and head jacket 5 through the jacket inlet 8 by a water pump 2 driven via a belt 29 and a pulley 30.
- It is constructed so that it is pumped and circulated in this order through the radiator 6 and the jacket inlet 8. 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 has an opening section 22a for each cylinder, an opening section 22b for each push rod, an opening section 22c for each water hole, and 22
d and 22f, and the required number of openings 22e for each mounting bolt are opened.

(First Embodiment) In the first embodiment of the present invention,
Among the water holes 4 that connect the cylinder jacket 3 and the head jacket 5, a water hole opening 22c of the head gasket 22 located in the middle of the front water hole 4a is provided with a shape memory material, for example, as shown in FIG. A temperature-sensitive operating valve 7 for expanding the passage is provided, which is made of an alloy. The operating temperature T1 for passage expansion of the temperature-sensitive operating valve 7 is the abnormally high temperature region T of the cooling water.
The temperature is set slightly lower than h. Then, the water hole opening part 22 of the head gasket 22 facing the back side water hole 4b
The temperature-sensitive valve 7 is not formed in f, and the water hole opening portion 22f of the rear water hole 4b is larger than the standard cross-sectional area Sb of the water hole opening portion 22c of the front water hole 4a. Set the passage cross-sectional area S to a large value. For this reason, cooling water easily flows into the cylinder jacket 3 and head jacket 5 at the rear of the engine 1, and the circulation amount of cooling water between the front water hole 4a and the rear water hole 4b is averaged, and the cylinder block 21 is evenly distributed. It is cooled and suppresses the occurrence of thermal distortion. Also, temperature-sensitive valve 7
Since the passage cross-sectional area S of the front water hole 4a is maintained at the reference cross-sectional area Sb, the circulating amount of cooling water does not become excessive and deterioration of combustion performance due to overcooling is prevented. Furthermore, the temperature-sensitive operating valve 7
As shown in FIG. 2(A), when the temperature T of the cooling water passing through the front water hole 4a rises to the passage expansion operating temperature T1, the front water hole The cross-sectional area S of the passageway 4a is expanded from the standard 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 can be 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) In the second embodiment of the present invention,
The temperature-sensitive valve 7 is formed as shown in FIG. 5, for example. Figure 2
As shown in (B), the temperature T of the cooling water passing through the water hole 4 is 1 higher than the valve opening temperature T2 (for example, 82°C) of the thermostat 31.
When the temperature rises to ~2° C. higher, the upper operating valve 7a is temperature-sensing operated to expand the passage cross-sectional area S of the water hole 4 from the reduced cross-sectional area S2 to the enlarged cross-sectional area S1. Immediately after starting, the cooling water temperature T reaches the valve opening temperature T2 of the thermostat 31.
(e.g. 82°C), if the temperature is less than 1 to 2°C higher than
Since the upper operating valve 7a is not temperature sensitive and the passage cross-sectional area S of its water hole 4 is narrowed down to the reduced cross-sectional area S2, the amount of circulating water is small and the cooling water temperature inside the engine rises rapidly and becomes uniform. be converted into 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 31 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 cause local supercooling of the otherwise uniform 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. When the cooling water temperature T is 1 to 2 degrees Celsius higher than the valve opening temperature T2 of the thermostat 31 (for example, 82 degrees Celsius), the upper operating valve 7a is temperature-sensingly operated, and the passage cross-sectional area S of the water hole 4 is becomes the enlarged cross-sectional area S1. Furthermore, when the cooling water temperature T rises to the passage expansion operating temperature T1,
The lower operating valve 7b is temperature-sensingly operated to expand the passage cross-sectional area S of the water hole 4 from the standard cross-sectional area Sb to the enlarged cross-sectional area S1. Therefore, the amount of circulating water increases, the cooling efficiency increases, and overheating of the engine 1 can be suppressed. Upper operating valve 7a in this embodiment
and the lower operating valve 7b can be configured by changing their positions.

The temperature-sensitive valve 7 has a head gasket 2.
Instead of forming it in the water hole opening 22c of No. 2, it may be formed in the cylinder jacket 3 or the head jacket 5. Furthermore, the temperature-sensitive operating valve 7 may be made of bimetal instead of being made of a shape memory alloy.

[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.

6 shows a conventional example, FIG. 6(A) is a diagram corresponding to FIG. 1(A), and FIG. 6(B) is a sectional view taken along the line Z-Z in FIG. 6(A).

[Explanation of symbols]

1...Multi-cylinder engine, 2...Water pump, 3...Cylinder jacket, 4...Water hole, 4a...Front water hole, 4b...Back water hole, 5...Head jacket, 6...Radiator, 7...Temperature-sensitive valve , 8...jacket inlet, 9...jacket outlet, T1
...Operating temperature for passage expansion, Th...Abnormally high temperature region, S...Passage cross-sectional area, S1...Expanded cross-sectional area, Sb...Reference cross-sectional area.

Claims (1)

[Claims] Claim 1: Cooling water for a multi-cylinder engine (1) is pumped by a water pump (2) from a jacket inlet (8) to a cylinder jacket (3), a water hole (4), and a head jacket (5).
), the jacket outlet (9), the radiator (6), and the jacket inlet (8) in this order.
The water hole (4) includes a front water hole (4a) located near the jacket inlet (8) and the jacket outlet (9), and a back water hole (4b) located on the far side. )
In the water cooling system for a multi-cylinder engine configured to include a plurality of water holes provided in parallel, the front side water hole (4a)
A temperature-sensitive operating valve (7) for expanding the passage is provided in the temperature-sensitive operating valve (7), and the operating temperature (T1) for expanding the passage of the temperature-sensitive operating valve (7) is set to a temperature slightly lower than the abnormally high temperature region (Th) of the cooling water. However, this temperature-sensitive operating valve (7) is temperature-sensitive operated when the temperature of the cooling water passing through the front water hole (4a) rises to the passage expansion operating temperature (T1). Front side water hole (4
The passage cross-sectional area (S) of a) is configured to be expanded from the standard cross-sectional area (Sb) to the enlarged cross-sectional area (S1), and is larger than the standard cross-sectional area (Sb) of the front water hole (4a). A water cooling device for a multi-cylinder engine, characterized in that the passage cross-sectional area (S) of the back side water hole (4b) is set to a large value.