JPH0353450B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an improvement in a cooling device for a water-cooled turbo engine.

(Prior Art) Conventionally, in a turbo engine, the turbine and the housing adjacent to the turbine become hot due to exhaust gas heat, and this heat is transferred to the bearing of the turbine shaft, causing the bearing to become extremely hot. There is a problem in that the temperature reaches a high temperature, causing seizure. As a means to solve this problem, it is known that a water jacket is formed in the turbo housing and engine cooling water flows through the water jacket to reduce the heat in the bearing part. (For example, 1987-
(Refer to Publication No. 152528).

However, in the conventional system described above, while the water pump operates to provide forced cooling with cooling water in the water jacket inside the turbo while the engine is running, when the engine is stopped, the water pump cannot be stopped. As a result, cooling water becomes stagnant within the water jacket.
As a result, the stagnant cooling water receives heat from the housing and bearings and generates steam bubbles, which stagnate inside the water-cooled turbo. Therefore, the presence of steam bubbles inhibits the cooling of the bearing by the cooling water.
Furthermore, the problem of seizure of the bearing portion arises.
Therefore, the following method has been considered in consideration of this problem and the simplification of the layout of the cooling water passage of the water-cooled turbo.

A water pump is installed at one end of the engine block, and a return passage returns cooling water from the other end of the engine block located above the water pump to the upper tank of the radiator, bypassing the radiator. , a water-cooled turbo having a bypass passage located below the return passage and connected to the suction side of the water pump, a cooling water suction port, and a cooling water discharge port provided above the suction port. and
The discharge port is connected to a midway portion of the bypass passage. In other words, by locating the discharge port of the water jacket of a water-cooled turbo above the suction port, steam bubbles in the water jacket can be drawn upward, and the discharge port can be communicated with the middle part of the bypass passage. Therefore, the arrangement of the cooling water passages is simplified. However, it has been found that with such a configuration, the following new problems occur.

Because the return passage side of the bypass passage is high, the steam bubbles generated when the upper air water pump stops are introduced into the radiator sub-tank through the radiator upper tank, even with a relatively short passage length. As the pressure increases, cooling water overflows from the radiator and steam bubbles are introduced into the sub-tank.The steam bubbles are then released into the cooling water that accumulates in the sub-tank, causing a loud noise. That's a problem.

In other words, the steam bubbles generated in the water jacket of a water-cooled turbo are introduced into the upper tank of the radiator installed at a high position through a passage that allows easy flow, and furthermore, a connecting pipe connects the inside of the upper tank of the radiator. (A function to introduce cooling water that overflows from the radiator, and a function to return the cooling water introduced into the sub-tank to the cooling water passage again when the pressure in the cooling water passage decreases (negative pressure occurs) due to a drop in water temperature.) Because of this, evaporation bubbles are introduced into the cooling water in the sub-tank through the pipe whose open end on the sub-tank side is located below the sub-tank, causing abnormal noise. This abnormal noise causes the sub-tank to vibrate, and since the sub-tank is attached to the vehicle body, the above-mentioned abnormal noise is transmitted into the vehicle interior through the vehicle body, causing discomfort to the driver.

A possible solution to this problem is to reduce the size of the vapor bubbles by cooling them.
For example, a passage is provided to connect the cooling water of a water-cooled turbo, the discharge port, and the suction side of the water pump to allow steam bubbles to pass through the cooling water for a long time. This sacrifices the simplification of the layout of the cooling water passages in the turbocharger, which increases the complexity and cost of the cooling system, and furthermore, the possibility of implementing it in a narrow bonnet space is reduced.

(Object of the Invention) The present invention has been made in view of the various problems mentioned above, and is aimed at preventing seizure of the bearing part of a water-cooled turbo caused by the generation of steam bubbles, and the generation of abnormal noises generated in the sub-tank. It is an object of the present invention to provide a cooling device for a water-cooled turbo engine that can achieve both prevention and prevention without complicating the cooling device.

(Structure of the Invention) In order to achieve the above object, the present invention includes a water pump disposed at one end of an engine block, and cooling from the other end of the engine block located above the water pump to an upper tank of a radiator. a return passage for returning water; a bypass passage that bypasses the radiator and is located below the return passage and connected to the suction side of the water pump; a cooling water suction port; and a bypass passage provided above the suction port. In the cooling system for a water-cooled turbo engine having a water-cooled turbo having a cooling water discharge port, the bypass passage is close to the connection position of the return passage to the engine block on the other end side of the engine block. The discharge port of the water-cooled turbo is connected to a midway part of the bypass passage, and the midway part is disposed below the connection position of the bypass passage with the engine block. A blocking means is provided in the more upstream bypass passage to prevent steam bubbles generated in the water-cooled turbo from flowing back into the engine when the water pump is stopped.

(Effects of the Invention) Since the present invention is configured as described above, by reliably discharging steam bubbles generated in the water jacket of the water-cooled turbo to the outside of the water-cooled turbo when the water pump is stopped, In addition to preventing the bearing from seizing, the above-mentioned prevention means guides the steam bubbles to the water pump side and passes them through the engine block where cold cooling water is present and the cooling water path to the return passage is long. Without complicating the cooling system, the flow of vapor bubbles into the sub-tank can be minimized and made small, thereby preventing the generation of abnormal noise.

(Example) Hereinafter, an example of the present invention will be described based on the drawings. FIGS. 1, 2, and 3 illustrate the first embodiment of the present invention.
This shows an embodiment, and an engine 1 includes an introduction passage 4 that guides cooling water heat exchanged in a radiator 2 to a water pump 3, and a water jacket 5 of a cylinder block 5 as an engine block.
a and the water jacket 6 of the cylinder head 6
It has a return passage 7 for returning the cooling water to the upper tank 2a of the radiator 2 via a. Also, the height position is above the water pump 3 and below the return passage 7 connected to the cylinder head 6, and the end face of the cylinder head 6 on the side to which this return passage 7 is connected (the other end side) , a thermo housing 9a housing the thermostat valve 9;
is provided, one end is connected to the suction side 3a of the water pump 3 from this thermo housing 9a,
A bypass passage 8 is provided which joins a return passage 8b of a heater (not shown) in the middle. Reference numeral 10 denotes a water-cooled turbo, and a suction port 10b provided on the lower side of a water jacket 10a formed inside is connected to a water jacket 5a of the cylinder block 5, and a suction port 10b provided on the lower side of a water jacket 10a formed inside is connected to the water jacket 5a of the cylinder block 5. A provided discharge port 10c is connected to a midway portion 8a of the bypass passage 8. Furthermore, the discharge port 10c is located below the lowest part of the downstream passage 8c of the bypass passage 8 from the midway part 8a to the suction side 3a of the water pump 3, and the midway part 8a of the bypass passage 8
A one-way valve is provided in the upstream passage 8d further upstream as a blocking means for preventing steam bubbles generated in the water jacket 10a of the water-cooled turbo 10 from flowing in the direction of the return passage 7 when the water pump 3 is stopped. 1
1 is provided. This one-way valve 11 has a third
As shown in the figure, two casings 11a, 11
b, a check ball 11c, a valve seat portion 11d, and a spring 11e.
The check ball 11c is pressed against the valve seat portion 11d by e, and only the flow of cooling water from the direction of the thermostatic valve 9 is allowed. Further, 12 is a sub-tank, and the sub-tank 12 and the upper tank 2a of the radiator 2 are connected by a connecting pipe 13.

With the above configuration, when the water pump 3 is stopped, the steam bubbles generated in the water jacket 10a of the water-cooled turbo 10 are reliably discharged into and out of the water-cooled turbo, and the heat between the bearing and the cooling water is released. By promoting replacement, it is possible to prevent seizure due to insufficient cooling of the bearing part, and the one-way valve 11 as a blocking means prevents steam bubbles from flowing in the direction of the return passage 7. However, once the water jackets 5a and 6 of the cylinder block 5 and cylinder head 6, where cold cooling water exists,
a, and the length of the cooling water passage through which the steam bubbles flow is long, and the steam bubbles flowing into the sub-tank 12 can be minimized and made small without complicating the cooling system. The generation of abnormal noise can be prevented.

Further, FIGS. 4 and 5 show a second embodiment of the present invention, and the same parts as the first embodiment are as follows.
The same reference numerals will be used and detailed explanation will be omitted. Upstream passage 8d upstream from the midway part 8a of the bypass passage 8
, from the middle part 8a to the suction side 3 of the water pump 3
A bent portion 14 as a blocking means is formed to a position lower than the lowest point of the downstream passage 8c up to A, and is bent H mm downward from the midway portion 8a.

In other words, before the steam bubbles reach the lowermost part of the bending part 14, the steam bubbles reach the suction side 3 of the water pump 3.
It flows into the cylinder block 5 and cylinder head 6 from a. In this second embodiment, even with a configuration in which the upstream passage 8d of the bypass passage 8 is only bent downward, the same effects as in the first embodiment can be obtained.

In addition, in the present Examples 1 and 2, the bypass passage 8 is
Although the present invention is applied to a heater in which the return passages 8b of the heaters are combined, in the case of a heater having separate return passages 8b, the outlet 10c of the water jacket 10a may be connected to either one of them.

[Brief explanation of drawings]

1, 2, and 3 show a first embodiment of the present invention. FIG. 1 is an overall view of the cooling device, and FIG. 2 is a height relationship of the cooling device in FIG. 1. FIG. 3 is a sectional view of the one-way valve 11 as the blocking means in FIG. 1. Further, FIGS. 4 and 5 show a second embodiment of the present invention, and FIG. 4 shows the main parts of the cooling device, and FIG.
The figure is an explanatory diagram showing the height relationship of the cooling device in FIG. 4. 1...Engine, 2...Radiator, 2a...
Upper tank, 3...Water pump, 3a...
...Suction side, 5...Cylinder block (engine block), 6...Cylinder head (engine block), 7...Return passage, 8...Bypass passage, 8
a...Middle part, 10...Water-cooled turbo, 10a...
Water jacket, 10b...Suction port, 10c
...Discharge port, 11...One-way valve (blocking means), 1
4...Bending portion (blocking means).

Claims (1)

[Claims] 1. A water pump is disposed at one end of the engine block, and a return passage for returning cooling water from the other end of the engine block located above the water pump to the upper tank of the radiator, bypassing the radiator; a water-cooled turbo having a bypass passage located below the return passage and connected to the suction side of the water pump; a cooling water suction port; and a cooling water discharge port provided above the suction port. In the cooling system for a water-cooled turbo engine, the bypass passage is connected to the other end of the engine block in close proximity to the connection position of the return passage to the engine block, and The discharge port is connected to a midway part of the bypass passage, and the midway part is disposed below the connection position of the bypass passage with the engine block, while the water pump is connected to the bypass passage upstream from the midway part when the water pump is stopped. A cooling device for an engine with a water-cooled turbo, characterized in that it is equipped with a blocking means for preventing steam bubbles generated in the water-cooled turbo from flowing back into the engine.