JP2632610B2 - Water cooling system for multi-cylinder engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water cooling device for a multi-cylinder engine.

[0002]

[Prerequisite Structure] A water cooling device for a multi-cylinder engine according to the present invention is assumed to have the following prerequisite structure, for example, as shown in FIG. That is, the cooling water of the multi-cylinder engine 1 is supplied from the jacket inlet 8 to the cylinder jacket 3, the water hole 4, the head jacket 5, and the jacket outlet 9 by the water pump 2.
-The radiator 6 and the jacket inlet 8 are configured to be circulated under pressure in this order. And the water hole 4
When viewed from the jacket inlet 8 and the jacket outlet 9, the front water hole 4a located on the near side and the rear water hole 4b located on the far side are provided in parallel.

[0003]

2. Description of the Related Art In the above premise structure, in the prior art,
The water hole 4 was formed to have the size of the reference sectional area Sb.

[0004]

In the above prior art,
There are the following problems: Since the water hole 4 is formed to have the size of the reference cross-sectional area Sb, when the load output does not exceed the rating of the engine 1, the circulation amount of the cooling water does not become excessive, and the deterioration of the combustion performance due to the overcooling is prevented. ing. However, the cylinder jacket 3 and the head jacket 5 at the rear of the engine 1
It is difficult for cooling water to flow into the cylinder block 2
The front of 1 is cooled relatively well, but the rear is less cooled. For this reason, thermal distortion occurs in the cylinder block 21 and, in extreme cases, seizure of the cylinder 25 occurs. Furthermore, at the time of overload output, the amount of heat generated increases, but the amount of circulation of the cooling water does not increase, so that the engine 1 may overheat. An object of the present invention is to suppress the occurrence of seizure of the cylinder 25 due to thermal distortion in the cylinder block 21 and the overheating of the engine 1 during overload.

[0005]

According to the present invention, in order to achieve the above-mentioned object, the following improved structure is added to the above-mentioned premise structure, for example, as shown in FIGS. That is, a passage expanding temperature-sensitive operating valve 7 is provided in the near side water hole 4a, and the passage expanding operating temperature T1 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. I do. The temperature-sensitive operating valve 7 operates when the temperature of the cooling water passing through the near-side water hole 4a rises to the above-described passage-widening operating temperature T1, and the temperature of the passage of the near-side water hole 4a is increased. The sectional area S is configured to be enlarged from the reference sectional area Sb to the enlarged sectional area S1. Further, the passage cross-sectional area S of the rear water hole 4b is set to a value larger than the reference cross-sectional area Sb of the front water hole 4a.

[0006]

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 above-described passage expanding operating temperature T1. At this time, the reference cross-sectional area S of the front side water hole 4a is
Since the passage cross-sectional area S of the rear water hole 4b is set to a value larger than that of the front water hole 4b, the cooling water easily flows into the cylinder jacket 3 and the head jacket 5 at the rear of the engine 1, and the front water hole 4a is The circulation amount of the cooling water with the water hole 4b is averaged, and the cylinder block 21 is cooled averagely, thereby suppressing the occurrence of thermal distortion. In addition, the temperature-sensitive operation valve 7 has 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 circulation amount of the cooling water does not become excessive, and a decrease in combustion performance due to supercooling is prevented. On the other hand, when the engine outputs an overload, the temperature of the cooling water passing through the water hole 4 becomes higher than the above-described passage expanding operating temperature T1 due to an increase in the amount of generated heat. For this reason, the temperature-sensitive operation valve 7 operates temperature-sensitively, and the front side water hole 4a is formed.
From the reference cross-sectional area Sb to the enlarged cross-sectional area S1
Expand to As a result, the circulation amount of the cooling water increases, the cooling capacity increases, and overheating of the engine 1 is suppressed.

[0007]

The present invention is configured and operated as described above, and has the following effects. Cooling water easily flows into the cylinder jacket and the head jacket at the rear of the engine, the circulation amount of the cooling water is averaged, the cylinder block is cooled evenly, and the occurrence of thermal distortion is suppressed. In addition, the amount of heat generated during overload output of the engine increases, while the temperature-sensitive operation of the temperature-sensitive valve increases the cross-sectional area of the water hole and increases the amount of circulation of cooling water, thus suppressing overheating of the engine. can do.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1A is a plan view of a main part of an engine head gasket,
1 (B) is a cross-sectional view taken along line XX of FIG. 1 (A), FIG. 2 is a diagram showing a relationship between a water hole cross-sectional area and a cooling water temperature, FIG. 3 is a plan view of a head gasket, and FIG. 1 is a schematic longitudinal sectional view of an engine. In FIG. 4, the engine 1 has 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 a top surface of the cylinder block 21 via a head gasket 22. , Forming the engine body. The cylinder block 21 includes a piston 26 that slides in the cylinder 25, a connecting rod 28 that connects the piston 26 to a crankshaft 27, and the like. Water holes 4 through which cooling water flows from the cylinder jacket 3 to the head jacket 5 are formed in the inner walls of the cylinder block 21 and the cylinder head 23.
They communicate through two. When viewed from the jacket inlet 8 and the jacket outlet 9, the water hole 4 is formed by providing a near side water hole 4a located on the near side and a far side water hole 4b located on the far side in parallel. Become. Cooling water of the engine 1 is supplied from a crankshaft 27 to a cylinder jacket 3, a water hole 4, a head jacket 5 by a water pump 2 driven through a belt 29 and a pulley 30.
-It is configured so that the radiator 6 and the jacket inlet 8 are circulated under pressure 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 air-cools the high-temperature cooling water by the radiator fan 32. As shown in FIG. 3, the head gasket 22 has an opening 22a for each cylinder, an opening 22b for each push rod, and an opening 22c for each water hole.
The required number of 2d and 22f and the opening part 22e for each mounting bolt are respectively opened.

(First Embodiment) In a first embodiment of the present invention,
As shown in FIG. 1, for example, as shown in FIG. 1, a shape memory is provided in a water hole opening 22c of a head gasket 22 located in the middle of a front water hole 4a among water holes 4 communicating the cylinder jacket 3 and the head jacket 5. A passage enlarging temperature-sensitive operating valve 7 made of an alloy is provided. The passage-expanding operating temperature T1 of the temperature-sensitive operating valve 7 is set in the abnormally high temperature region T of the cooling water.
h is set to a temperature slightly lower than h. The water hole opening 22 of the head gasket 22 facing the back side water hole 4b.
f, the temperature-sensitive operating valve 7 is not formed, and the reference cross-sectional area Sb of the water hole opening 22c of the front water hole 4a is larger than that of the water hole opening 22f of the rear water hole 4b. The passage sectional area S is set to a large value. For this reason, the cooling water easily flows into the cylinder jacket 3 and the head jacket 5 at the rear of the engine 1, and the circulation amount of the cooling water between the front side water hole 4 a and the back side water hole 4 b is averaged, so that the cylinder block 21 is averaged. It is cooled and suppresses the occurrence of thermal distortion. Also, the temperature-sensitive operating valve 7
Keeps the passage cross-sectional area S of the front water hole 4a at the reference cross-sectional area Sb, so that the circulation amount of the cooling water does not become excessive, and the deterioration of combustion performance due to overcooling is prevented. Further, the temperature-sensitive operation valve 7
As shown in FIG. 2A, when the cooling water temperature T passing through the near side water hole 4a rises to the above-described passage enlarging operation temperature T1, the temperature sensing operation is performed, and the near side water hole is operated. The passage sectional area S of 4a is configured to be enlarged from the reference sectional area Sb to the enlarged sectional area S1. For this reason, the circulation amount of the cooling water increases, the cooling capacity increases, and overheating of the engine 1 can be suppressed. 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 always supplied to promote thermally severe cooling between cylinders.

(Second Embodiment) In a second embodiment of the present invention,
The temperature-sensitive operating valve 7 is formed, for example, as shown in FIG. FIG.
As shown in FIG. 3B, the temperature T of the cooling water passing through the water hole 4 is one more than the valve opening temperature T2 of the thermostat 31 (eg, 82 ° C.)
When the temperature rises to about 2 ° C. higher, the upper operating valve 7a performs a temperature-sensitive operation to expand the passage sectional area S of the water hole 4 from the reduced sectional area S2 to the enlarged sectional area S1. Just after the start, the cooling water temperature T becomes equal to the valve opening temperature T2 of the thermostat 31.
(E.g., 82 ° C.) below 1-2 ° C.
Since the upper working valve 7a does not perform temperature sensing and the passage sectional area S of the water hole 4 is reduced to the reduced sectional area S2, the cooling water circulation amount is small and the cooling water temperature inside the engine rises rapidly and becomes uniform. Be transformed into As a result, there is no need to close the thermostat 31 and bypass the radiator 6 by the bypass passage 33 as in the conventional case, and the thermostat 31 can be eliminated. Further, when the thermostat 31 is opened, a large amount of low-temperature cooling water in the radiator 6 flows into the cylinder jacket 3, which may locally supercool the interior of the engine that has been made uniform, resulting in cooling loss.
By eliminating the thermostat 31, it is possible to eliminate engine overcooling in such a case, so that cooling loss at room temperature is small. When the cooling water temperature T is higher than the temperature of the thermostat 31 by 1 to 2 ° C. higher than the valve opening temperature T2 (for example, 82 ° C.), the upper operating valve 7a operates temperature-sensitively and the passage cross-sectional area S of the water hole 4 is increased. Is the enlarged sectional area S1. Further, when the cooling water temperature T rises to the passage expanding operating temperature T1,
The lower actuating valve 7b is configured to perform a temperature-sensitive operation so as to enlarge the passage sectional area S of the water hole 4 from the reference sectional area Sb to the enlarged sectional area S1. For this reason, the circulation amount of the cooling water increases, and the cooling temperature increases, so that the overheating of the engine 1 can be suppressed. Upper working valve 7a in this embodiment
The lower operating valve 7b and the lower operating valve 7b can be configured by changing their positions with respect to each other.

The temperature-sensitive operating valve 7 includes a head gasket 2
Instead of being formed in the second water hole opening 22c, it may be formed in the cylinder jacket 3 or the head jacket 5. Further, the temperature-sensitive operating valve 7 may be formed of a bimetal instead of being formed of a shape memory alloy.

[Brief description of the drawings]

1A and 1B show an embodiment of the present invention. FIG. 1A is a plan view of a main part of an engine head gasket, and FIG.
FIG. 3A is a sectional view taken along line XX of FIG.

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

FIG. 3 is a plan view of a head gasket according to the embodiment of the present invention.

FIG. 4 is a schematic longitudinal sectional view of an engine according to the embodiment of the present invention.

FIG. 5 shows another embodiment of the present invention, and FIG.
FIG. 5A is a diagram corresponding to FIG. 5A, and FIG.
FIG.

6A and 6B show a conventional example, FIG. 6A is a view corresponding to FIG. 1A, and FIG. 6B is a cross-sectional view taken along line ZZ of FIG. 6A.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Multi-cylinder engine, 2 ... Water pump, 3 ... Cylinder jacket, 4 ... Water hole, 4a ... Front side water hole, 4b ... Back side water hole, 5 ... Head jacket, 6 ... Radiator, 7 ... Temperature-sensitive operation valve , 8 ... jacket entrance, 9 ... jacket exit, T
1: working temperature for passage enlargement, Th: abnormally high temperature region, S: sectional area of passage, S1: enlarged sectional area, Sb: reference sectional area.

Claims (1)

(57) [Claims] A water pump for cooling water of a multi-cylinder engine (1)
According to (2), the pressure is circulated from the jacket inlet (8) to the cylinder jacket (3), the water hole (4), the head jacket (5), the jacket outlet (9), the radiator (6), and the jacket inlet (8) in this order. When viewed from the jacket inlet (8) and the jacket outlet (9), the water hole (4) has a near water hole (4a) located on the near side and a rear water hole (4a) located on the far side. In a water cooling device for a multi-cylinder engine configured to be configured such that a side water hole (4b) is provided in parallel with the side water hole (4b), a passage enlarging temperature-sensitive operating valve (7) is provided in the front side water hole (4a), Operating temperature (T1) for expanding the passage of the temperature-sensitive operating valve (7)
Is set at a temperature slightly lower than the abnormally high temperature region (Th) of the cooling water, and the temperature-sensitive operation valve (7) is connected to the front side water hole.
When the temperature of the cooling water passing through (4a) rises to the above-mentioned passage expanding operating temperature (T1), the temperature-sensitive operation is performed, and the passage cross-sectional area (S) of the water hole (4a) on the front side is cut off as a reference. It is configured to expand from the area (Sb) to the enlarged cross-sectional area (S1), and the passage cross-sectional area of the back water hole (4b) is larger than the reference cross-sectional area (Sb) of the front water hole (4a). A water cooling system for a multi-cylinder engine, wherein (S) is set to a large value.