JPS62113818A - Cooling device for engine equipped with water cooled turbo - Google Patents

Abstract

PURPOSE:To prevent the occurance of unusual noise which is caused by the bleeding of vapor bubbles into cooling water in a subtank storing cooling water overflowed from a radiator by providing a cooling water inlet port for the upper section of the tank. CONSTITUTION:In a cooling device, a turbo charger is cooled by engine cooling water fed via a radiator, and a subtank 19 is provided for storing cooling water overflowed from the radiator. In this case, a passage 20 which inducts cooling water overflowed from the radiator, is provided, and a passage 21 which returns the stored cooling water in said tank 19 back to the radiator, is also provided. A cooling water inlet port 20a of the passage 20 is arranged in the upper section (underneath a cap 29) of said tank 19, besides, a cooling water return port 21a of the passage 21 is arranged at the bottom of said tank 19. This constitution an induct cooling water into an upper space above the water level of the tank 19 for achieving the desired end.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an engine cooling system, particularly a water-cooled type in which a turbo supercharger provided in the engine is cooled by cooling water circulating in a cooling system. The present invention relates to a cooling device for a turbo engine.

(Prior art) In recent years, turbo superchargers have been used in automobile engines to supercharge intake air using exhaust gas energy in order to improve intake air filling efficiency and engine output. Although it has been put into practical use, this turbocharger has a configuration in which the turbine is driven by high-temperature exhaust gas discharged from the engine, so the temperature rises significantly due to the heat of the exhaust gas, and as a result, the lubrication The oil deteriorates early, causing problems such as seizure between the turbine shaft and the bearing, or reduced durability. To deal with this problem, for example, according to Japanese Utility Model Application Publication No. 58-152528, a cooling water passage (water jacket) is formed in the turbine housing of a turbocharger, and an engine cooling water jacket is formed in the passage. A device has been proposed in which cold W water is supplied that circulates through the system.According to this, the supercharger is actively cooled by the cooling water, and the above-mentioned lubricating oil in the supercharger is cooled. Deterioration, decrease in durability, etc. are prevented.

However, when such a water-cooled turbocharger is provided, the following problems occur when the engine is stopped. In other words, when the engine is stopped, the water pump that circulates coolant is also stopped immediately, cutting off the supply of coolant to the turbocharger, which is at a particularly high temperature. The cooling water that remains in the cooling water passage in the turbocharger boils due to the heat of the turbocharger, generating water vapor bubbles, which flow into the radiator through the engine cooling system and cause the radiator to boil. Cooling water inside overflows. By the way, in the engine cooling system as described above, a sub-tank is connected to the radiator through a communication passage.
As mentioned above, the overflowing cooling water is introduced into the sub-tank, but one end of the communication passage is connected to the bottom of the tank because it is necessary to return the cooling water from the sub-tank to the radiator when the cooling water temperature drops. will be placed in Therefore, when the air bubbles generated in the cooling passage in the turbocharger as described above overflow from the radiator with the cooling water and are introduced into the sub-tank when the engine is stopped, the air bubbles are introduced from the bottom of the sub-tank. However, in that case, since replenishment cooling water is stored in the tank, air bubbles will be released into this cooling water, and at this time, an abnormal sound (bobbing sound) will be generated.

This noise is then propagated from the sub-tank through the vehicle body into the cabin, causing discomfort to the occupants.

(Object of the Invention) The present invention addresses the above-mentioned problems regarding a cooling system for an engine equipped with a water-cooled turbocharger, and improves the structure of a communication passage that communicates a radiator and a sub-tank. This prevents the generation of abnormal noise caused by water vapor bubbles generated in the cooling water passage of the turbocharger being introduced into the sub-tank via the radiator and communication passage when the engine is stopped. The purpose of this is to eliminate the problem that the abnormal noise is propagated from the sub-tank through the vehicle body into the vehicle interior, causing discomfort to the occupants.

(Structure of the Invention) In order to achieve the above object, the present invention is characterized by the following structure.

That is, in an engine cooling system that is configured to cool a turbo supercharger with engine cooling water supplied through a radiator, and is provided with a sub-tank that stores cooling water that overflows from the radiator,
The sub-tank is provided with a cooling water inlet for introducing cooling water from the radiator and a cooling water return port for returning the cooling water stored in the tank to the radiator. The cooling water inlet is opened at the top of the sub-tank, and the chilled water return port is opened at the bottom of the sub-tank.

By the way, according to this type of cooling device, when the engine is operating, cooling water is circulated by the water pump driven by the engine and is supplied to the water jacket and turbocharger inside the engine. When the water pump stops, the water pump is also stopped immediately and the supply of cooling water is cut off, causing the cooling water that remains in the cooling water passage in the turbocharger, which is in a particularly high temperature state due to the heat of the exhaust gas, to boil. and water vapor bubbles are generated. This air bubble then flows into the sub-tank via the radiator.

In that case, according to the present invention, the bubbles are no longer released into the cooling water stored in the sub-tank,
It will be released into the air above the surface of the cooling water.

On the other hand, when cold water is returned to the radiator from the sub-tank due to a drop in pressure due to a drop in the cooling water temperature or a decrease in the amount of cooling water in the radiator, the cooling water is drained into the bottom of the sub-tank. Since the cooling water is returned from the cooling water return port, the cooling water in the sub tank is reliably returned to the radiator without sucking air into the radiator.

Note that the communication passage that communicates the radiator and the sub-tank may be constructed of two passages, one for introducing cooling water and the other for returning water, and the end on the sub-tank side may be opened in the positional relationship as described above. Alternatively, it may be constructed of one passage that serves both for introducing the cooling water and for returning the cooling water, and one end of the passage may be branched and opened into the sub-tank as described above.

(Effects of the Invention) As described above, according to the present invention, in a cooling system for an engine equipped with a water-cooled turbo supercharger, cooling water is introduced from the radiator side into the upper part of the sub-tank communicated with the radiator. Since the mouth is opened, when the water vapor bubbles generated in the turbo supercharger when the engine is stopped are introduced into the sub-tank via the radiator, the cooling water stored in the sub-tank is released. Since the bubbles are released into the air above the surface, the generation of abnormal noise caused by the bubbles being released into the cooling water in the sub-tank, as in the conventional case, is prevented. This solves the problem that the abnormal noise is propagated from the sub-tank through the vehicle body into the vehicle interior, causing discomfort to the occupants. In the present invention, since the cold instant water return port to the radiator side is opened at the bottom of the sub-tank, the cooling water stored in the sub-tank is reliably returned to the radiator side as in the conventional case. Problems such as air being sucked into the radiator will not occur.

(Example) Embodiments of the present invention shown in the drawings will be described below.

First, the cooling system of a water-cooled turbo engine to which the present invention is applied will be explained based on FIG. A main introduction passage 5 introduces cooling water from the water jacket 3a formed around each cylinder 4 of the engine 3 to a water jacket 3a formed around each cylinder 4... A main circulation path 7 is constituted by these. Cooling water is forced to circulate through the main circulation path 7 by the operation of a water pump 9 that is attached to one side of the engine 3 and driven by the crankshaft (not shown) of the engine 3 via a belt 8. As a result, the main introduction passage 5
The cooling water that is introduced into the water jacket 3a from above and heated to a high temperature by cooling the surroundings of each cylinder 4...4 is returned to the radiator 2 via the main return passage 6, and is After being brought to a low temperature state, it is supplied to the main introduction passage 5 again.

Further, this cooling system 1 is provided with a bypass passage 10 that directly communicates the main introduction passage 5 and the main return passage 6, and a branch part 11 of the bypass passage 10 from the main return passage 6 is provided with A thermostatic valve 12 is provided,
When the engine 3 is warmed up, the bypass passage 10 and the water jacket 3a of the engine 3 form a circulation path that does not pass through the radiator 2. Furthermore, in this cooling system 1, each of the above-mentioned cylinders 4...
A passage through which cooling water flows is also formed inside the intake manifold 13 that guides intake air to the intake manifold 13.
3a is the 2fll outlet 3b, 3 formed in the engine 3.
b, respectively. The cooling water that has reached a high temperature within the water jacket 3a of the engine 3 is introduced into the passages 13a, 13a within the manifold 13, thereby heating the intake air passing through the manifold 13. The vaporization and atomization of the fuel mixture supplied into the cylinders 4...4 is promoted.

Further, the outlet 1 of the passage in this intake manifold 13
3b is a heater unit 14 for heating the interior of the vehicle to a high temperature.
It is communicated with the bypass passage 10 via.

On the other hand, the engine 3 is equipped with a water-cooled turbo supercharger 15, and a cooling passage (water jacket) (not shown) is formed inside a turbine housing 15a of the supercharger 15. This cooling passage includes a training passage 16 led from the lower part of the engine 3 and the bypass passage 1.
The sub-return passage 17 leading to the auxiliary return passage 17 is in communication with the sub-return passage 17, and a sub-circulation path 18 is constituted by these passages. The cooling water, which has been introduced from the main introduction passage 5 in the main circulation path 7 into the water jacket 3a of the engine 3 and has not yet reached a high temperature state, flows from the auxiliary grooved passage 16 to the turbo supercharging 115.
The cooling water that has reached a high temperature by cooling the supercharger ta15 is guided to the cooling passage in the turbine housing 15a, thereby cooling the supercharger 15, and the cooling water that has reached a high temperature by cooling the supercharger ta15 in this way is It is returned to the end of the main introduction passage 5 on the engine 3 side via the return passage 17 and the bypass passage 10.

Furthermore, in addition to the above configuration, this cooling system 1 is equipped with a sub-tank 19 for storing cooling water overflowing from the radiator 2, and two passages that communicate the sub-tank 19 and the radiator 2, that is, A cooling water introduction passage 20 that guides the overflowing cooling water from the radiator 2 side to the sub tank 19 side, and the sub tank 19
A cooling water return passage 21 is provided for returning the cooling water stored therein to the radiator 2 side again. and,
As shown in FIG. 2, the end of the cooling water introduction passage 20 of the two passages 20 and 21 on the radiator 2 side is formed in a projecting shape on the upper part of the body member 2a of the radiator 2. A cylindrical member 2b whose upper end serves as a cooling water inlet
The cooling water return passage 21 is opened from one side to the outer space A formed in the member 2b, and the end of the cooling water return passage 21 is connected to a radiator IP knob 22 that covers the upper end of the cylindrical member 2b.
It is opened from the top to an inner space B similarly formed within the cylindrical member 2b. Here, the radiator cap 22 includes a seal member 23 whose peripheral edge is pressed against the upper end of the cylindrical member 2b, and a seal member 23 that hangs down from the central lower surface of the member 23 and connects the outer space A and the inner space B. A cylindrical separator 24 is fixed to partition the cylindrical member 2b, and an upper space C at the upper part of the cooling water stored in the radiator 2 (inside the body member 2a) and an outer space A are connected in the cylindrical member 2b. A first valve 25 that communicates with or shuts off communication, and a second valve 26 that connects or shuts off communication between the upper space C and the inner space B are provided. And the first valve 25 is
A cylindrical guide part 25a having a flange formed at the lower end of the separator 24 installed therein and accurately guiding the valve 25 in the vertical direction; and a first seating part 25b attached to the lower end of the guide part 25a. , and a coil spring 27 installed between the upper surface of the seating portion 25b and the lower surface of the radiator cap 22 to urge the valve 25 downward. 1 Seating part 2
5b is seated on the stepped surface 2b' formed on the cylindrical member 2b, whereby the outer space A and the upper space C are held in a closed state. The second valve 26 also includes a valve body 26a having a square cross section, which is loosely inserted into a circular through hole 25b' formed in the center of the first seating part 25b with a predetermined gap, and a valve body 26a having a square cross section. A disk-shaped second seating portion 26b fixed to the lower end of the valve body 26a is attached between the lower surface of the flange formed at the upper end of the valve body 26a and the upper surface of the first seating portion 25b. The second M seat part 26b is seated on the lower surface of the thousandth seat part 25b as shown by the solid line in the same figure in normal times. The inner space B and the upper space C are in a closed state.

However, the ends of the cooling water introduction passage 20 and the cooling water return passage 21 on the sub-tank 19 side are each constructed in a similar manner.

That is, as shown in FIG. 3, the respective ends of the cooling water introduction and return passages 20.
The opening of the cooling water introduction passage 20 into the sub-tank 19, that is, the cooling water inlet 20a, is inserted into the tank 19 by penetrating the sub-tank cap 29 that covers the upper part of the tank 19. The opening of the cooling water return passage 21, that is, the cooling water return port 21a is located at the top of the tank 19 (directly below the sub-tank cap 29), and the opening of the cooling water return passage 21, that is, the cooling water return port 21a, is located at the bottom of the tank 19 (directly below the bottom surface 19a of the sub-tank 19).
is placed in a position where there is a slight gap between the

Next, the operation of the above embodiment will be explained.

When the engine 3 is in operation, the water pump 9 shown in FIG. 4...4 and the water-cooled turbo supercharger 15 are respectively cooled well. In other words, the cooling water brought to a low temperature in the radiator 2 first passes through the main introduction passage 5 as shown by arrow a, and then is guided into the water jacket 3a of the engine 3 as shown by the arrow, and is guided into the water jacket 3a of the engine 3 as shown by the arrow. Most of the cooling water led into the interior of the cooling water 3a cools the surroundings of each of the cylinders 4...4 which are in a high temperature state, and then passes through the main return passage 6 as shown by arrow C to It is returned into the radiator 2. In that case,
A portion of the cooling water introduced into the water jacket 3a as described above flows from the lower part of the engine 3 into the sub-grooved passage 16 as shown by the arrow d before cooling the surroundings of each of the cylinders 4...4. The cooling water that has flowed in and passed through the passage 16 flows into the turbine housing 15a of the turbocharger 15.
The supercharger 15, which is in a high temperature state, is cooled by being guided through a cooling passage (water jacket) formed inside, and then flows out into the sub-return passage 17 as shown by the arrow e, and further flows into the sub-return passage 17 as shown by the arrow As shown by f, it passes through the bypass passage 10 and is returned to the main introduction passage 5.

However, when the engine 3 stops operating while cooling the cylinders 4...4 and the turbocharger 15 which are in a high temperature state as described above, the driving of the water pump 9 is also stopped. Cooling water is no longer circulated through the main circulation path 7 and the sub-circulation path 18, and at this time, the cooling water staying in the cooling passage in the turbocharger 15, which is in a particularly high temperature state, is absorbed by the heat of the turbocharger 15. This results in boiling and generation of water vapor bubbles within the cooling passage. By the way, these water vapor bubbles flow into the radiator 2 from the cooling passage in the turbocharger 15 via, for example, the sub-return passage 17, the bypass passage 10, and the main introduction passage 5, and as a result, the radiator 2 This may lead to a situation where the cooling water inside the sub tank 19 overflows, but the overflowing cooling water is introduced into the sub tank 19 in the following manner.

That is, when water vapor bubbles flow into the body member 2a of the radiator 2 shown in FIG. 2 from the turbocharger 15 side as described above, these bubbles enter the cooling water stored in the body member 2a. As a result, the volume of the cooling water increases, and the upper space C in the body member 2a is filled with the cooling water mixed with air bubbles. At this time, the second valve 2 is pushed up against the force to the position shown by the chain line in the figure.
6 is also pushed up while seated on the lower surface of the first valve 25). As a result, the upper space C filled with the cooling water is communicated with the outer space A in the cylindrical member 2b formed at the upper part of the body member 2a, and the cooling water passes through the outer space A. It flows into the cooling water introduction passage 20.

The cooling water that has flowed into the cooling water introduction passage 20 in this way passes through the passage 20 and then enters the sub-tank 19 shown in FIG.
In that case, even if replenishment cooling water is stored in the sub-tank 19 as shown in the figure, since the introduction port 20a is located at the upper part of the sub-tank 19, The cooling water introduced from the inlet 20a is discharged into the air above the level of the stored cooling water. As a result, when the overflowing cooling water is introduced into the sub-tank 19 through the introduction port 20a of the cooling water introduction passage 20, water vapor generated in the cooling passage in the turbo supercharging 115 is added to the cooling water. The generation of abnormal noise due to air bubbles being mixed in is prevented. That is, for example, as in the conventional case, the cooling water introduction passage 2
If the introduction port 20a of 0 is arranged at the bottom of the sub-tank 19, water vapor bubbles will be mixed into the cooling water in the sub-tank 19 from the introduction port 20a, and when this mixture is mixed, an abnormal sound (boobbling sound) will be generated. However, according to the present invention, the above-mentioned air bubbles are not mixed into the cooling water in the sub-tank 19, so the occurrence of abnormal noise as described above is prevented. Therefore, the problem that this abnormal noise is propagated from the sub-tank 19 through the vehicle body into the passenger compartment, causing discomfort to the occupants, is eliminated.

Furthermore, in the case where the cooling water stored in the sub-tank 19 is returned to the radiator 2, the second
As the liquid level of the cooling water stored in the radiator 2 shown in the figure is lowered due to a drop in water temperature or disappearance of air bubbles, the air pressure in the upper space C in the body member 2a is reduced, and this air pressure is As the pressure decreases, the first valve 25 is seated at the position shown by the solid line in the figure, and the upper space C and the outer space A are closed, and the second valve 26 resists the spring force of the conical coil spring 28. The above upper space C and inner space B are moved downward to the positions shown by chain lines in the figure.
and communicate with each other through a gap around the valve body 26a of the valve 26. As a result, the inside of the cooling water return passage 21 becomes a negative pressure state, and the cooling water stored in the sub-tank 19 flows into the inner space B through the passage 21, and further from the space B to the body member. In this case, the opening of the return passage 21 on the sub-tank 19 side, that is, the cooling water return port 21a, is located at the bottom of the tank 19 as shown in FIG. The cooling water stored in the tank 19 is reliably returned to the radiator 2 side.

In the above embodiment, the communication passage that communicates the radiator and the sub-tank is configured with two passages, one for introducing the cooling water and the other for returning the cooling water. It may be configured with a single passage that serves both for introducing the cooling water and for returning the cooling water, and the end of this passage on the sub-tank side may be in the following passage state.

That is, as shown in FIG.
The opening is opened on the upper surface of the sub-tank cap 32 that covers the upper part of the tank 1, and this opening is used as the cooling water inlet 30a, and the lower end of the branch passage 33 that branches from the end 30' of the passage 3o and hangs downward. Cooling water return port 3
3a. Directly below the radiator cap 32, there is provided a rubber member 34 that functions as a valve for communicating and shutting off the cooling water inlet 30a and the inside of the sub-tank 31''. The overflowing cooling water is introduced into the tank 31 from the end 30' of the dual-purpose passage 30 through the cooling water inlet 30a arranged at the upper end of the sub-tank 31. Since the member 34 is pushed down by the pressure of the cooling water to the state shown by the chain line, the cooling water flows into the tank 31 through the path shown by the arrow 9. When the cooling water is returned to the radiator side, the cooling water flows out from the cooling water return port 33a arranged at the bottom of the sub-tank 31 through the branch passage 33 to the dual-purpose passage 30. Since the rubber member 34 has been returned to the state shown by the solid line in the figure, when the cooling water flows out from the branch passage 33 into the dual-purpose passage 30, it will not be returned to the sub-tank 31. , this subtank 3
A passage 35 that communicates with the inside of the tank 31 and leads to the outside air is provided in the upper part of the sub-tank 31. This is for discharging cooling water to a predetermined location outside. In this way, also in this embodiment, the cooling water overflowing from the radiator is introduced from the cooling water inlet 30a provided at the upper end of the sub-tank 31, so water vapor bubbles are mixed into the cooling water. The generation of abnormal noise caused by
Since the cooling water in the tank 31 is returned to the radiator side via the branch passage 33 and the dual-purpose passage 30, the cooling water in the tank 31 is reliably returned.

[Brief explanation of drawings]

The drawings show embodiments of the present invention, and FIG. 1 is a perspective view showing a schematic configuration of a cooling system for a water-cooled turbo engine in a first embodiment of the present invention, and FIG. 3rd enlarged sectional view of main parts showing passage condition of the radiator side end of the communication passage that communicates the radiator and the sub-tank;
The figure is an enlarged cross-sectional view of a main part showing the passage condition at the sub-tank side end of the communication passage, and FIG. It is a diagram. 1... Cooling device (cooling system), 2... Radiator,
3... Engine, 15... Turbo supercharger, 19°3
1... Sub tank, 20a, 30a... Cooling water inlet, 21a, 33a... Cooling water return port.

Claims (1)

[Claims] (1) A cooling system for a water-cooled turbo engine that is configured to cool a turbo supercharger with engine cooling water supplied through a radiator, and is equipped with a sub-tank that stores cooling water that overflows from the radiator. The sub-tank is provided with a cooling water inlet for introducing cooling water overflowing from the radiator, and a cooling water return port for returning the cooling water stored in the tank to the radiator, and A cooling device for a water-cooled turbo engine, characterized in that a cooling water inlet is opened at the top of the sub-tank, and the cooling water return port is opened at the bottom of the sub-tank.