JPH0746726Y2 - Head cooling system for water-cooled vertical multi-cylinder engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION << Industrial Application Field >> The present invention relates to a cooling device for a cylinder head in a water-cooled multi-cylinder vertical engine.

<< Prior Art >> In a water-cooled multi-cylinder vertical engine, a cylinder jacket formed in a cylinder block and a head jacket formed in a cylinder head are dispersed in a lower wall portion of the cylinder head to form a plurality of cooling water inlet holes. The water outlet of the water pump communicates with the cylinder jacket, and the cooling water outlet to the radiator is opened in the head jacket, and the cooling water sent from the water pump into the cylinder jacket is passed through the cylinder jacket and head jacket. The engine was cooled by circulating it to the radiator.

<Problems to be solved> However, in the conventional cooling device, the cooling water inlet holes are formed by being dispersed in the lower wall of the head jacket, and the cooling water outlet holes are formed only in the front side wall portion of the head jacket. there were. In addition, since the head jacket has a wide water passage on the exhaust port side to allow a large amount of cooling water to flow to the exhaust port side, which is a heating source, the cooling water outlet hole extends from the vertical plane passing through the crankshaft core to the exhaust port side. It is arranged unevenly. Therefore, if the engine continues to operate in a tilted left / right direction for a long time, or if it continues to run in a tilted front / rear position for a long time, steam accumulates in the part that is higher due to the tilt, and cooling water is collected in this part However, there is a problem in that the head cannot be cooled and is partially overheated, resulting in head distortion and head cracking.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above problems and provide a head cooling device that can cool a cylinder head satisfactorily even when operation is continued in an inclined posture.

<Means for Solving the Problems> In order to achieve the above object, the present invention provides a plurality of cooling water inlet holes at a plurality of positions in the longitudinal direction with respect to a lower wall of a cylinder head 7 of a water-cooled vertical multi-cylinder engine. 10 are dispersed and opened, and a cooling water outlet 11 is opened in the front part of the cylinder head 7 so that the cooling water in the cylinder jacket 6 of the cylinder block 4 is passed from each cooling water inlet hole 10 to the head jacket of the cylinder head 7. 8 into this head jacket 8
In a head cooling device for a water-cooled vertical multi-cylinder engine, which is configured so as to flow in a positive direction and flow out from a cooling water outlet 11, among a plurality of cooling water inlet holes 10, a cylinder head 7
The opening cross-sectional area of the cooling water inlet hole 10a located at the rear portion of the lower wall is formed larger than that of the cooling water inlet hole 10 at other locations, and the cooling water amount control valve 14 is opposed to the cooling water inlet hole 10a located at the rear portion. In addition to the above arrangement, the overheat detection operating device 16 is provided on the upper rear side of the head jacket 8, and the cooling water amount control valve 14 is connected to the overheat detection operating device 16. When it is detected that the temperature is equal to or lower than the preset appropriate temperature, the cooling water amount control valve 14 is brought close to the cooling water inlet hole 10a, and the passage cross-sectional area thereof is set to a preset appropriate value during normal operation. On the other hand, when it is detected that the rear portion of the head jacket 8 has exceeded the proper temperature, the cooling water amount control valve 14 is separated from the cooling water inlet hole 10a located at the rear portion, and the passage cross-sectional area thereof is set during normal operation. To a value greater than the appropriate value of It is characterized in that it is configured to change.

<< Operation >> The present invention operates as follows, for example, as shown in FIG.

The overheat detection actuating device 16 causes the cooling water amount control valve 14 to approach the cooling water inlet hole 10a in the rear part during a normal operation in which the temperature of the rear part of the head jacket 8 becomes equal to or lower than the appropriate temperature. Due to the approach of the cooling water amount control valve 14, the cooling water inlet hole 10a in the rear part is provided.
The passage cross-sectional area of is a proper value during normal operation, and the amount of cooling water flowing into the rear part of the head jacket 8 through the rear cooling water inlet hole 10a is limited to the required amount of cooling water during normal operation. To be done. That is, at the time of normal operation, the required amount of cooling water flows in the rear portion of the head jacket 8,
The rear part of the cylinder head 7 can be appropriately cooled without causing excess or deficiency in cooling.

On the other hand, for example, when the engine tilts downward to the front, the cooling water outlet
When the rear side of the head jacket 8 becomes higher than 11, the cooling water warmed by heat absorption from the cylinder head 7 tries to rise in the head jacket 8 to the rear side. The flow of cooling water to 11 becomes poor. Along with this, the cooling water does not smoothly flow into the rear portion of the head jacket 8 through the rear cooling water inlet hole 10a.

For this reason, high-temperature cooling water or steam easily accumulates in the rear portion of the head jacket 8, cooling efficiency of the rear portion of the cylinder head 7 decreases, and the rear portion in the head jacket 8 tends to be overheated.

On the other hand, when the temperature of the rear portion of the head jacket 8 exceeds the proper temperature, the overheat detecting and operating device 16 separates the cooling water amount control valve 14 from the rear cooling water inlet hole 10a. Then, the passage cross-sectional area of the rear cooling water inlet hole 10a becomes larger than the appropriate value during normal operation, and the amount of cooling water flowing into the rear portion of the head jacket 8 through the rear cooling water inlet hole 10a is usually It is significantly larger than the required cooling water volume during operation.

As a result, the large amount of cooling water flowing into the rear portion of the head jacket 8 through the rear cooling water inlet hole 10a strongly causes the high temperature cooling water that tends to accumulate in the rear portion of the head jacket 8 toward the cooling water outlet 11 side. It is swept away and the rear part of the cylinder head 7 is strongly cooled by the large amount of cooling water.

<< Embodiment >> A drawing shows an embodiment of the present invention, and FIG. 1 is an enlarged view of a main part,
FIG. 2 is a schematic configuration diagram showing a cooling system of a water-cooled vertical four-cylinder engine, and FIG. 3 is a plan view of a main part of a cylinder head.

In this engine cooling system, a radiator (2) is arranged on the front side of the engine body (1), and a lower tank (3) of the radiator (2) is arranged on the front side wall of a cylinder block (4) of the engine body (1). Communicate with water pump (5), water pump (5) and cylinder block (4)
A cooling water inlet hole, which is connected to the cylinder jacket (6) in the inside thereof and has the cylinder jacket (6) and the head jacket (8) formed in the cylinder head (7) transparently provided on the lower wall of the cylinder block (7). The head jacket (8) communicates with the upper tank (12) of the radiator (2) through the cooling water outlet (11) which is open to the front side wall of the cylinder head (7). It is configured by

The cooling water inlet holes (10) that are transparently provided on the lower wall of the cylinder head (7) are arranged in a distributed manner corresponding to each cylinder (13), and are located farthest from the water pump (5) side. Around the cylinder (13a) located at
By cooling the 3), the already-cooled cooling water is supplied, so the cooling water inlet hole (10a) formed corresponding to the cylinder (13a) located at the innermost side.
The cooling water inlet hole (10) in which the opening cross section is the other part
It is formed to be larger than the above, and a large amount of cooling water is circulated so that it can be cooled in the same manner as other portions.

According to the present invention, in the cooling system formed as described above, the opening cross-sectional area of the cooling water inlet hole (10a) formed corresponding to the cylinder (13a) located at the innermost side is required for normal operation. The cooling water amount control valve (14) is arranged corresponding to the cooling water inlet hole (10a) while forming the cooling water amount larger than the cross sectional area.
Is operated based on a command from an overheat detecting device (16) fixed to the upper wall (15) of the head jacket (8).

The cooling water amount control valve (14) is provided on the cooling water inlet hole (10a) side during normal operation to a position where the amount of inflow water from this cooling water inlet hole (10a) is secured to the required cooling water amount during normal operation. Approaching When the engine is operated in a tilted posture and the flow of cooling water in the head jacket (8) changes, causing overheating in the head jacket (8), the temperature rise is detected by the overheat detecting device (16). ), And operates so as to separate the cooling water amount control valve (14) from the cooling water inlet hole (10a). This allows the cooling water inlet hole (10
The amount of cooling water flowing from a) into the head jacket (8) increases.

The overheat detection device (16) includes a temperature-sensitive operating member (17) formed of thermowax, a metal having a large coefficient of thermal expansion, a shape memory alloy, or the like, and a backup spring (18) inside a casing (19). The cooling water amount control valve (14) has a valve shaft (20) interlockingly connected to the temperature-sensitive operating member (17).

In the above embodiment, the cooling water amount control valve (14) is arranged corresponding to the cooling water inlet hole (10) used during normal operation so that the amount of cooling water flowing from the inlet (10) is controlled. However, the cooling water inlet hole (1
Separately from (0), a cooling water communication hole for communicating the cylinder jacket (6) with the head jacket (8) is provided in the lower wall of the cylinder head (7) corresponding to a location in the head jacket (8) where overheating is likely to occur. The cooling water communication hole may be opened and closed by the cooling water flow control valve (14) to increase the cooling water flow.

The location of the cooling water amount control valve (14) is not limited to around the cylinder on the side far from the water pump, and it goes without saying that it is placed at an appropriate location in consideration of the usage conditions of the engine.

<Effect> The present invention has the following effects because it is configured and operates as described above.

When the rear part of the head jacket exceeds the proper temperature, the overheat detection operation device separates the cooling water amount control valve from the cooling water inlet hole in the rear part, and makes the passage cross-sectional area larger than the appropriate value during normal operation. Therefore, the amount of cooling water flowing into the rear part of the head jacket through the cooling water inlet hole of the rear part can be significantly increased from the amount of cooling water required during normal operation.

Therefore, for example, when the rear part of the head jacket becomes higher than the cooling water outlet due to the inclination of the engine to the front, the cooling water warmed by the heat absorption from the cylinder head tries to rise to the rear part inside the head jacket. As a result, the flow of cooling water from the rear part of the head jacket to the cooling water outlet becomes poor, and the rear part of the cylinder head becomes hot and tries to be overheated.In this case, however, cooling to the rear part of the head jacket is performed as described above. By significantly increasing the amount of cooling water required for normal operation, a large amount of cooling water can strongly push the high-temperature cooling water that tends to accumulate in the rear part of the head jacket toward the cooling water outlet side. .
In other words, even if the rear part of the head jacket becomes high, a large amount of cooling water can drain the high-temperature cooling water that tends to collect in the rear part of the head jacket from the head jacket, and also can clean the rear part of the cylinder head that is about to be overheated. It can be cooled strongly.

This prevents overheating of the rear of the cylinder head,
It is possible to reliably prevent distortion of the cylinder head and cracking of the head due to overheating.

[Brief description of drawings]

The drawing shows an embodiment of the present invention, and FIG. 1 is an enlarged view of the main part,
FIG. 2 is a schematic configuration diagram showing a cooling system of a water-cooled vertical four-cylinder engine, and FIG. 3 is a plan view of a main part of a cylinder head. 4 ... Cylinder block, 6 ... Cylinder jacket, 7 ...
Cylinder head, 8 ... Head jacket, 10 ... Cooling water inlet hole, 11 ... Cooling water outlet, 14 ... Cooling water amount control valve, 16 ... Overheat detection device (overheat detection operation device).

Claims (1)

[Scope of utility model registration request] 1. A plurality of cooling water inlet holes (10) are dispersedly opened at a plurality of positions in a longitudinal direction with respect to a lower wall of a cylinder head (7) of a water-cooled vertical multi-cylinder engine, and the cylinder is also provided. A cooling water outlet (11) is opened in the front part of the head (7), and the cooling water in the cylinder jacket (6) of the cylinder block (4) is passed through the cooling water inlet holes (10) to the cylinder head (7). In the head cooling device for a water-cooled vertical multi-cylinder engine configured to flow into the head jacket (8), flow forward in the head jacket (8), and flow out from the cooling water outlet (11). Among the plurality of cooling water inlet holes (10), the cooling water inlet hole (10) located at the rear portion of the lower wall of the cylinder head (7).
The opening cross-sectional area of a) is formed larger than the cooling water inlet hole (10) at other locations, and the cooling water amount control valve (14) is arranged to face the cooling water inlet hole (10a) located at the rear part. Along with the head jacket (8), an overheat detection actuating device (16) is provided on the upper rear side.
Is provided, and the cooling water flow control valve (1
4) is connected, and when the overheat detection actuating device (16) detects that the rear portion of the head jacket (8) is at or below a preset proper temperature, the cooling water control valve (14) is turned on. While approaching the cooling water inlet hole (10a) and setting the passage cross-sectional area to a preset appropriate value during normal operation, the rear portion of the head jacket (8) exceeded the appropriate temperature. When this is detected, the cooling water amount control valve (14) is separated from the cooling water inlet hole (10a) located at the rear part, and the passage cross-sectional area is set to a value larger than the appropriate value during the normal operation. A head cooling device for a water-cooled vertical multi-cylinder engine, which is configured to be changed.