JP2012092751A - Engine cooling system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an engine cooling system that can improve engine cooling efficiency by efficiently separating fine bubbles from a coolant and can eliminate various kinds of failures of a cooling system caused by the mixture of the bubbles.SOLUTION: The engine cooling system includes: the sealed cooling system 30 that forcibly circulates the coolant of the engine 11 via a coolant channel 31; a radiator 12 that emits the heat of the coolant by exchanging the heat with air; and a reserve tank 20 that forms a liquid reservoir 20a for reserving part of the coolant and an air accumulation space 20b that is located above the liquid reservoir, and varies a reserve quantity in accordance with a volume change of the coolant in the cooling system 30. The engine cooling system includes a ceiling side part 41j of an inner wall surface 41a that is tilted so that a cross-sectional area of the channel is more expanded in a more downstream in a specific channel 31s, and a gas collection tube 41 that aggregates the bubbles in the coolant in a downstream and perpendicularly upward side of the specific channel 31s where a communication opening 41p is formed so that it communicates with the inside of the reserve tank 20 near an upper end in a perpendicular direction of the inner wall surface 41a of the gas collection tube 41.

Description

  The present invention relates to an engine cooling system, and more particularly to an engine cooling system suitable for gas-liquid separation of bubbles and cooling liquid in a cooling liquid when the cooling liquid is forcibly circulated in a sealed cooling water system.

  In an engine cooling system that cools a water-cooled engine, in general, the coolant in a cooling path having a radiator and a thermostat is forcibly circulated by a water pump, and a radiator cap with a built-in pressure adjustment valve is used. The boiling point is increased by pressurizing a cooling liquid whose volume increases as the temperature rises. In the past, it was often used to overflow the increased volume of coolant near the radiator cap when the engine was running. Recently, however, when the coolant temperature is high, the increased volume of coolant flows out to the reserve tank. A simple sealed type is often used in which the coolant is replenished into the radiator from the reserve tank side through a pressure regulating valve when the coolant temperature decreases and the coolant temperature decreases. In addition, a cap with a pressure adjustment valve equivalent to the radiator cap is arranged on the reserve tank side, and an air pocket that can absorb the volume change of the coolant is formed in the reserve tank, thereby reducing the frequency of opening and closing the pressure adjustment valve. Thus, a completely sealed type is used in which the stability of the internal pressure of the cooling path is improved, and bubbles generated in the cooling path can be efficiently separated from the cooling liquid in the reserve tank.

  As an engine cooling system for separating bubbles from the cooling liquid in the cooling path in this way, for example, a bulging portion is provided at the lower part of the reserve tank, and the horizontal cross-sectional area of the liquid level of the cooling liquid in the reserve tank is reduced. It is restricted to the upper side of the tank to prevent the lower side pipe connection part from being exposed on the coolant level, and further from the inlet formed in the pipe connection part of the reserve tank. There is known a system in which a partition wall for partitioning the inside of a reserve tank is provided so as to increase the flow path of the coolant between the outlet and the outlet, thereby improving the gas-liquid separation performance (see, for example, Patent Document 1).

  In addition, a reserve tank that extends in the left-right direction while being connected to the upper ends of the left and right radiator tanks of a transverse flow type (cross flow type) radiator, an upper air reservoir chamber and a lower liquid reservoir inside the reserve tank And a gas-liquid separation shielding plate in which a small hole is formed in the vicinity of one end portion on the cooling liquid inlet side, and a small hole is formed in the vicinity of one end portion on the coolant inlet side, and the liquid reservoir chamber from the radiator tank side through the small hole While allowing air to escape to (the space above the shielding plate), the shielding plate suppresses the flow of air from the liquid reservoir chamber side to the radiator tank side due to the inclination of the coolant level. It is known (see, for example, Patent Document 2).

  In addition, a reserve tank is connected to the upper tank of the downflow type radiator, and a hose that bypasses the radiator from the upper tank to the vicinity of the thermostat is provided so that air can be vented from the upper tank even when the thermostat is closed immediately after starting. A device that can perform work is known (for example, see Patent Document 3).

  In addition, a pressure tank is provided in the reserve tank connected to the upper tank of the radiator, and a water inlet and its sealing plug are provided in the upper tank of the radiator for quick water injection (for example, Patent Documents). 4).

  In addition, although not an engine cooling system, there is known an apparatus including a header tank capable of gas-liquid separation while connecting an inner jacket passage and an outer coolant passage to an upper portion of an electric motor jacket (for example, a patent) Reference 5).

  As the cooling liquid, for example, JIS K2234 (engine antifreeze coolants) two types of long life coolant (ethylene glycol added with a rust preventive, anticorrosive, oxidation inhibitor, antifreeze, etc .; hereinafter, LLC And a mixture of water.

JP 2008-190443 A JP 2002-038945 A JP 2002-004858 A JP 2005-188381 A JP 2002-120570 A

  However, in the conventional engine cooling system as described above, when fine bubbles are generated in the coolant, it is difficult for the bubbles to reach the reserve tank side from the radiator tank. In addition, when very fine bubbles are generated in the cooling liquid, even if measures are taken to improve the gas-liquid separation performance in the reserve tank as described in Patent Document 1, the very fine bubbles are generated. May pass through the reserve tank. For this reason, the cooling liquid in which fine bubbles are mixed circulates in the cooling liquid passage, and the cooling liquid may become milky, and the cooling efficiency of the engine may be significantly reduced.

  In addition, when the coolant becomes milky, the flow of coolant in the heater core can easily reverberate in the cabin of the vehicle, or increase in oxygen and water vapor can cause deterioration of the radiator, etc. or rust. It was. Furthermore, there is a problem that cavitation and erosion are easily caused.

  Therefore, the present invention can improve the cooling efficiency of the engine by efficiently separating the fine bubbles mixed in the cooling liquid from the cooling liquid, and eliminate various problems of the cooling water system due to the mixing of micro bubbles. An engine cooling system that can be used is provided.

  In order to solve the above problems, the engine cooling system according to the present invention includes (1) a sealed cooling water system for forcibly circulating engine coolant through a sealed coolant passage, and heat exchange between the heat of the coolant and air. And a liquid reservoir part storing a part of the cooling liquid therein and an air reservoir part located above the liquid reservoir part, and according to the volume change of the cooling liquid in the cooling water system An engine cooling system comprising a reserve tank that changes a storage amount of the coolant, and an inner wall surface that is inclined so that a passage cross-sectional area increases toward a downstream side in a specific passage section of the coolant passage. A gas collecting pipe for collecting bubbles in the cooling liquid on the downstream side in the specific passage section and on the upper side in the vertical direction, and in the vicinity of the upper end in the vertical direction of the inner wall surface of the gas collecting pipe. Wherein the communicating port communicating with the interior of the Butanku is formed.

  In the engine cooling system according to the present invention, in the gas collecting pipe forming the specific passage section of the coolant passage, the bubbles in the coolant are integrated while gathering on the downstream side and the upper side in the vertical direction in the specific passage section. Since it changes into a large bubble, it becomes easy to reach the reserve tank side through a communication port that opens near the vertical upper end of the inner wall surface of the gas collection tube. Therefore, it becomes difficult for the coolant containing fine bubbles to circulate in the coolant passage, effectively reducing the cooling efficiency of the engine, and eliminating various problems in the cooling water system caused by the inclusion of microbubbles. It becomes possible to do.

  In the engine cooling system according to the above (1), (2) the reserve tank introduces and discharges a part of the cooling liquid during the forced circulation, and removes bubbles in the cooling liquid from the introduced cooling liquid. It is desirable to have a gas-liquid separation chamber for separation. With this configuration, bubbles that are gradually integrated and enlarged while gathering on the downstream side in the specific passage section and the upper side in the vertical direction easily reach the reserve tank side through the communication port of the gas collection pipe, and the inside of the reserve tank Is removed from the cooling liquid by gas-liquid separation at. Therefore, the gas-liquid separation performance is further improved.

  The engine cooling system according to the above (2) preferably has (3) a radiator tank into which the radiator introduces the coolant, and a radiator core through which the coolant distributed from the radiator tank passes. The gas collecting pipe is constituted by a part of the radiator tank. In this case, it is not necessary to provide a separate gas collection pipe, and an engine cooling system having excellent gas-liquid separation performance can be provided without increasing costs and assembly man-hours.

  In the engine cooling system according to the above (3), (4) the radiator tank constitutes an upper tank extending in a substantially horizontal direction above the radiator core, and the radiator core has a downflow type tube. It is preferable that the inner wall surface of the gas collecting pipe formed by a part of the radiator tank is inclined in the vertical direction at least at the ceiling side portion. Accordingly, a relatively long specific passage section can be easily secured in the upper tank of the downflow type radiator. Therefore, even if fine bubbles are mixed in the cooling liquid in the upper tank, the fine bubbles circulate in the cooling water system due to the collection of the bubbles in the gas collection pipe and the gas-liquid separation in the reserve tank. Surely removed.

  In the engine cooling system according to the above (4), (5) the radiator tank has a downstream ceiling wall surface inclined in a direction opposite to the specific passage section in a passage section downstream from the specific passage section. Preferably it is. In this case, even if air accumulates in the corner on the downstream end in the upper tank downstream of the specific passage section during operation of the engine, when the engine stops, the bubbles move to the communication port side of the gas collection tube. Therefore, at the time of restart, the bubbles are easily introduced into the reserve tank, and are removed from the coolant by gas-liquid separation in the reserve tank.

  In the engine cooling system according to the above (4) or (5), (6) an upstream passage section that guides the coolant that has flowed into the radiator tank to the specific passage section, and the specific passage inside the radiator tank. A downstream passage section through which the coolant that has passed through the passage section is passed, and the specific passage section are formed, respectively, and the upstream passage section, the downstream passage section, and the specific passage section from the radiator core side to the radiator core side. A plurality of openings for distributing the cooling liquid may be formed. With this configuration, the bubbles in the coolant in the upper tank can be more accurately gathered downstream and vertically upward in the specific passage section, and the gas-liquid separation performance is further improved. In addition, it is more preferable that the specific passage section is longer than the upstream passage section and the downstream passage section.

  In the engine cooling system according to the above (3), (7) the radiator tank is constituted by an inlet-side radiator tank located on one side of the radiator core in the horizontal direction, and the radiator core is a cross-flow tube. And the inner wall surface of the gas collecting pipe constituted by the inlet-side radiator tank is inclined at least in the horizontal direction outward at the upper part of the horizontal outer side wall. Good. In this case, a relatively long specific passage section can be easily secured in the radiator tank at the inlet side of the crossflow type radiator (particularly above the coolant inlet), and even small bubbles in the cooling liquid can be downstream in the specific passage section. As it gathers on the upper side and the upper side in the vertical direction, it gradually increases in size, and reaches the reserve tank side through the communication port of the gas collection tube in a state where gas-liquid separation is easy. Therefore, even if fine bubbles are mixed in the coolant in the upper tank, the fine bubbles are reliably removed from the coolant by collection in the gas collection tube and gas-liquid separation in the reserve tank.

  In the engine cooling system according to the above (2), (8) the gas collecting pipe may be mounted in the middle of a coolant hose constituting a part of the sealed coolant passage. . In this case, a gas collection tube can be easily added to an existing completely sealed engine cooling system to improve the gas-liquid separation performance, and parts constituting the gas collection tube can be shared.

  According to the present invention, in the gas collecting pipe forming the specific passage section of the coolant passage, the bubbles in the coolant are integrated into a large bubble while gathering on the downstream side in the specific passage section and the upper side in the vertical direction. It is designed to reach the reserve tank side with a bubble size that allows easy gas-liquid separation through the communication port of the gas collection tube, so that fine bubbles mixed in the cooling liquid can be efficiently separated from the cooling liquid. It is possible to provide an engine cooling system that can improve the cooling efficiency of the engine and solve various problems of the cooling water system caused by the mixing of microbubbles.

1 is a schematic block configuration diagram of an engine cooling system according to a first embodiment of the present invention. 1 is a schematic side view of an engine cooling system according to a first embodiment of the present invention. It is a schematic front sectional view of the upper tank of the radiator in the engine cooling system according to the first embodiment of the present invention. It is a schematic block diagram of the principal part of the engine cooling system which concerns on 2nd Embodiment of this invention. It is the principal part schematic block diagram which shows the radiator vicinity in the engine cooling system which concerns on 3rd Embodiment of this invention.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
1 to 3 show a first embodiment of the engine cooling system of the present invention.

  The engine cooling system of this embodiment cools the coolant of an engine that is a water-cooled internal combustion engine mounted on a vehicle, and the present invention is applied to an engine cooling system including a downflow type radiator. It is what.

  First, the configuration will be described.

  As shown in FIGS. 1 and 2, an engine cooling system 1 according to this embodiment includes a water jacket 11w (a part of a coolant passage) formed inside an engine 11, a downflow radiator 12, an engine 11 and a radiator inlet side hose 13 and a radiator outlet side hose 14 (in this embodiment, an upper hose and a lower hose) interposed between the radiator 11 and the radiator 12, and a water pump disposed on the upstream end side of the water jacket 11w of the engine 11 15, a thermostat 16 with a bottom bypass valve disposed on the suction side of the water pump 15, and a sealed reserve tank 20 having a tank cap 22 with a pressure regulating valve. The engine cooling system 1 is a completely sealed type in which the coolant of the engine 11 is forcedly circulated by a water pump 15 through a sealed coolant passage 31 and the inside of the reserve tank 20 is pressurized as a part of the coolant passage. The cooling water system 30 is configured.

  The radiator 12 is a heat exchanger that discharges the heat of the coolant that has passed through the water jacket 11w of the engine 11 by heat exchange with air, and the air from the front of the vehicle as the vehicle travels or the cooling fan (not shown) rotates. Coolant heat can be transferred to the flow. The radiator 12 includes an upper tank 12a on the inlet side for introducing the coolant that has passed through the water jacket 11w of the engine 11, a lower tank 12b on the outlet side that returns the cooled coolant after heat exchange to the engine 11 side, and these upper tanks 12a. And a downflow type radiator core 12c disposed between the lower tank 12b. Here, the radiator core 12c is integrally coupled to a plurality of cooling tubes 12ct through which cooling liquid distributed from the upper tank 12a passes in a substantially vertical direction and the cooling tubes 12ct, as schematically shown in part in FIG. The plurality of cooling fins 12cf are configured.

  The radiator inlet-side hose 13 and the radiator outlet-side hose 14 are arranged so that the coolant of the engine 11 communicates with the water jacket 11w in the engine 11 and the heat exchange passage portion (not shown) in the radiator 12 of the coolant passage 31. This is a pipe having heat resistance and pressure resistance for connecting the inlet 11a and the coolant outlet 11b to the upper tank 12a and the lower tank 12b of the radiator 12, respectively.

  The water pump 15 is built in the engine 11 so as to be rotated by power from the engine 11, and hot coolant flows into the radiator 12 from the engine 11 through the radiator inlet side hose 13, and is cooled by heat exchange in the radiator 12. The cooling fluid is supplied to the engine 11 side through the radiator outlet side hose 14 in a predetermined circulation path in the coolant passage 31 or further from the engine 11 to the heater pipes 18a and 18b and the vehicle compartment side heater core 19 (heater heat The coolant is circulated through the exchanger. The thermostat 16 is disposed on the suction side of the water pump 15 and opens and closes the main valve portion communicating with the lower tank 12b of the radiator 12 according to the coolant temperature, thereby allowing the coolant flow rate through the radiator outlet hose 14 to open and close. In the cold state where the coolant temperature (coolant temperature) is low, the main valve portion is closed to limit the flow rate of coolant through the radiator outlet hose 14, By opening the bypass valve portion, the bypass passage 32 extending from the coolant outlet 11 b side of the engine 11 to the suction side of the water pump 15 is opened, and the coolant that has passed through the water jacket 11 w of the engine 11 is again supplied to the engine 11. It can be refluxed inside.

  The radiator inlet side hose 13, the radiator outlet side hose 14, the water pump 15 and the thermostat 16 are the same as known ones.

  The reserve tank 20 is connected to the upper tank 12a of the radiator 12 via the reserve tank connection pipes 29a and 29b, and from the lower tank 12b of the radiator 12 to the suction side of the water pump 15, for example, the upstream side of the main valve portion of the thermostat 16, respectively. It is connected.

  The reserve tank 20 is formed with a water injection port (not shown) for injecting a cooling liquid at an upper portion thereof, and a tank main body 21 for storing the injected cooling liquid together with air above the tank main body so as to seal the water injection port. And a tank cap 22 with a known pressure regulating valve that is detachably provided near the water inlet 21.

  Although not shown in detail, the pressure regulating valve built in the tank cap 22 is opened when the pressure in the reserve tank 20 reaches a preset upper limit pressure due to the temperature rise and expansion of the coolant, and the air is opened. A function of discharging a part of the air in the reservoir 20b to the atmosphere, and when the pressure in the reserve tank 20 is about to fall below the atmospheric pressure due to the temperature drop and contraction of the coolant, the valve is opened and the inside of the reserve tank 20 is opened. It is a well-known thing which exhibits the function which prevents that becomes negative pressure.

  As shown in FIG. 2, the reserve tank 20 includes a liquid reservoir 20 a that stores a part of the cooling liquid therein and an air reservoir 20 b that is located above the liquid reservoir 20 a. The amount of coolant stored in the liquid reservoir 20a is changed in accordance with the volume change of the coolant. Also, the tank body 21 of the reserve tank 20 is connected to the other end portion of the cylindrical first communication pipe portion 23 connected to the upper tank 12a of the radiator 12 on one end side, and the main valve portion of the thermostat 16 on one end side. The other end portion of the second communication pipe portion 24 connected to the upstream side by piping is connected, and the other end portions of the first communication pipe portion 23 and the second communication pipe portion 24 are cooled in the reserve tank 20. It is separated by a predetermined distance in the liquid passing direction.

  The reserve tank 20 forms a gas-liquid separation chamber 25 that introduces and discharges a part of the cooling liquid that is being forcedly circulated by the water pump 15 and separates bubbles in the introduced cooling liquid from the cooling liquid. The gas-liquid separation chamber 25 forms part of the coolant passage 31 that is pressurized and sealed by forming part of the second bypass passage 33 that bypasses the radiator 12.

  On the other hand, in this embodiment, the gas collection pipe 41 is configured by a part of the upper tank 12a of the radiator 12.

  The gas collecting pipe 41 is arranged in the vertical direction at least in the ceiling side portion 41j so that the passage cross-sectional area increases toward the downstream side in the specific passage section 31s located in the upper tank 12a of the radiator 12 in the coolant passage 31. The inner wall surface 41a is inclined so that fine bubbles in the coolant passing through the upper tank 12a of the radiator 12 are gathered on the downstream side in the specific passage section 31s and on the upper side in the vertical direction.

  Further, a communication port 41p that communicates with the gas-liquid separation chamber 25 in the reserve tank 20 through the reserve tank connection pipe 29a is formed in the vicinity of the upper end in the vertical direction of the inner wall surface 41a of the gas collection pipe 41.

  The upper tank 12a of the radiator 12 extends in a substantially horizontal direction above the radiator core 12c, and the gas collection pipe 41 is located at an intermediate portion in the extending direction of the upper tank 12a.

  Specifically, the upper tank 12a of the radiator 12 passes through the upstream passage section 31u (upstream passage section) for guiding the coolant flowing into the upper tank 12a to the specific passage section 31s and the specific passage section 31s. A downstream passage section 31d (downstream passage section) through which the coolant flows is formed, and a specific passage section 31s located between them is formed. The specific passage section 31s includes the upstream passage section 31u and the downstream passage section 31s. The passage length is set larger than each of the side passage sections 31d.

  A plurality of openings 31e for distributing the coolant from the upstream passage section 31u, the downstream passage section 31d, and the specific passage section 31s to the radiator core 12c side are formed on the inner bottom surface side of the upper tank 12a of the radiator 12. ing. The plurality of openings 31e are formed by upper ends of a plurality of cooling tubes 12ct extending in the vertical direction in parallel to each other so as to constitute the radiator core 12c of the radiator 12. The plurality of cooling tubes 12ct are coupled to each other by a plurality of cooling fins 12cf so that air can pass through the radiator core 12c of the radiator 12 in the vehicle front-rear direction.

  Further, as shown in FIG. 3, the ceiling side portion 41 j facing the plurality of openings 31 e on the upper end side of at least the plurality of cooling tubes 12 ct on the inner wall surface 41 a of the gas collection tube 41 is connected to the radiator inlet side hose 13. On the upstream end side of the upper tank 12a close to the coolant inlet 12i, the upper tank 12a is positioned at a height equivalent to the center height h7 of the coolant inlet 12i in the vertical direction and on the downstream end away from the coolant inlet 12i. Is inclined at an angle θ2 with respect to a substantially horizontal line parallel to the inner bottom surface of the upper tank 12a so as to be positioned at the height h1 on the uppermost side in the vertical direction, and from the coolant inlet 12i in the specific passage section 31s. The cross-sectional area of the passage gradually increases in accordance with the separation distance. In addition, the ratio of the increase in the passage cross-sectional area with respect to the increase in the separation distance from the coolant inlet 12i may be constant or may vary.

  In the downstream passage section 31d, the upper tank 12a of the radiator 12 is opposite to the ceiling side portion 41j of the specific passage section 31s with respect to a substantially horizontal line parallel to the inner bottom surface of the upper tank 12a (from the coolant inlet 12i). The downstream ceiling wall surface 41k is inclined at an angle θ1 (the height decreases as the separation distance increases), and the upstream passage section 31u also cools against a substantially horizontal line parallel to the inner bottom surface of the upper tank 12a. It has an upstream ceiling wall surface 41n inclined by an angle θ3 so that the height decreases as the distance from the liquid inlet 12i increases.

  In addition, the inner wall surface 41a of the gas collecting pipe 41 is a ceiling between the ceiling side portion 41j of the specific passage section 31s and the downstream ceiling wall surface 41k in the same direction as the downstream ceiling wall surface 41k and with respect to the inner bottom surface of the upper tank 12a. The steeply inclined surface 41h forms an inclination angle θ4 sufficiently larger than the inclination angles θ2 and θ1 of the side portion 41j and the downstream ceiling wall surface 41k. Further, as shown in FIG. 3, the distance L1 from the center of the coolant inlet 12i to one end of the upper tank 12a is larger than the distance L2 from the center of the coolant inlet 12i to the other end of the upper tank 12a. The one side widths L8 and L9 of the bulging portion 41e upward of the upper tank 12a with respect to the center of the coolant inlet port 12i are substantially equal to each other, and the height h8 of the bulging portion 41e is the ceiling side portion 41j of the gas collecting pipe 41. It is lower than the top height h1. Further, the center height h8 of the coolant inlet port 12i is lower than the center height h2 of the communication port 41p. However, the diameter of the coolant inlet 12i is larger than the diameter of the communication port 41p. The total length L3 of the specific passage section 31s is slightly longer than the total length L6 of the ceiling side portion 41j, and a substantially horizontal portion having a length corresponding to the difference is formed near the top of the ceiling side portion 41j. The opening position of the communication port 41p is on the rear side of the upper tank 12a in the drawing, but may be on the front side or near the top of the ceiling side portion 41j or the steeply inclined surface 41h. The separation distance L4 from the center of the coolant inlet 12i to the upstream end of the specific passage section 31s is such that the coolant passage in the upper tank 12a can be once narrowed between the bulging portion 41e and the gas collection pipe 41. The distance may be close to the one-side width L8 so as to be slightly larger than the one-side width L8 of the bulging portion 41e. The upper end height h3 and the lower end height h4 of the downstream ceiling wall surface 41k are equal to the upper end height h6 and the lower end height h5 of the upstream ceiling wall surface 41n, respectively.

  Next, the operation will be described.

  In the engine cooling system 1 of the present embodiment configured as described above, in the gas collecting pipe 41 that forms the specific passage section 31s of the coolant passage 31, bubbles in the coolant are downstream in the specific passage section 31s. Since the air bubbles are integrated into a large bubble while gathering on the upper side and the upper side in the vertical direction, the gas reaches the reserve tank 20 through the communication port 41p that opens near the upper end in the vertical direction of the inner wall surface 41a of the gas collection tube 41. It becomes easy. Therefore, it is difficult for the coolant mixed with fine bubbles to circulate in the coolant passage 31 and the cooling efficiency of the engine 11 is effectively suppressed. For example, the problem that the flow sound of the coolant in the heater core reverberates in the cabin of the vehicle, the problem that the radiator 12 and the like are easily deteriorated or rusted due to an increase in oxygen and water vapor, and cavitation and erosion are likely to occur. The problem of becoming) can be solved.

  In the present embodiment, the reserve tank 20 introduces and discharges a part of the coolant that is being forcedly circulated by the water pump 15 and separates the bubbles in the introduced coolant from the coolant. Therefore, bubbles that are gradually integrated and enlarged while gathering on the downstream side in the specific passage section 31 s and the upper side in the vertical direction are expanded to the reserve tank 20 side through the communication port 41 p of the gas collection pipe 41. Air bubbles can be easily reached, and air bubbles are accurately removed from the coolant by gas-liquid separation in the reserve tank 20. Therefore, the gas-liquid separation performance in the engine cooling system 1 is further improved.

  Furthermore, in this embodiment, since the gas collection pipe 41 is constituted by a part of the upper tank 12a of the radiator 12, there is no need to separately provide the gas collection pipe 41 as an independent dedicated part, and costs and assembly are reduced. The engine cooling system 1 having excellent gas-liquid separation performance can be provided without increasing the number of steps.

  In addition, the upper tank 12a extends in a substantially horizontal direction above the radiator core 12c, and the radiator core 12c has a plurality of cooling tubes 12ct extending in the vertical direction, and is formed by a part of the upper tank 12a. Since the inner wall surface 41a of the collection pipe 41 is inclined in the vertical direction at least at the ceiling side portion 41j, a relatively long specific passage section 31s can be easily secured in the upper tank 12a of the downflow type radiator 12. Therefore, even if fine bubbles are mixed in the cooling liquid in the upper tank 12a, the fine bubbles circulate in the cooling water system 30 by collecting the bubbles in the gas collection pipe 41 and separating the gas and liquid in the reserve tank 20. Is reliably removed from the cooling liquid.

  Further, the upper tank 12a of the radiator 12 has a downstream ceiling wall surface 41k inclined in the opposite direction to the specific passage section 31s in the downstream passage section 31d downstream of the specific passage section 31s. Even if air accumulates at the corner on the downstream end in the upper tank 12a on the downstream side of the specific passage section 31s, when the engine 11 is stopped, the bubbles of the gas collection pipe 41 are formed along the downstream ceiling wall surface 41k. Since it moves to the communication port 41p side, the bubbles are easily introduced into the reserve tank 20 when the engine 11 is restarted, and are removed from the coolant by gas-liquid separation in the reserve tank 20.

  Moreover, in the upper tank 12a of the radiator 12, an upstream passage section 31u that reduces the passage sectional area immediately before the specific passage section 31s, and a downstream passage section 31d that reduces the passage sectional area downstream of the specific passage section 31s; A longer specific passage section 31s is formed between them, and a plurality of openings 31e for distributing the coolant from the upstream passage section 31u, the downstream passage section 31d and the specific passage section 31s to the radiator core 12c side are formed. Therefore, the bubbles in the coolant in the upper tank 12a can be more accurately gathered on the downstream side in the specific passage section 31s and on the upper side in the vertical direction.

  As described above, according to the present embodiment, in the gas collection pipe 41 that forms the specific passage section 31s of the coolant passage 31, the bubbles in the coolant are on the downstream side in the specific passage section 31s and the upper side in the vertical direction. It is integrated into a large bubble and gathers into a large bubble, and reaches the reserve tank 20 side with a bubble size that allows easy gas-liquid separation through the communication port 41p of the gas collection tube 41. The engine cooling system 1 can improve the cooling efficiency of the engine 11 by efficiently separating fine bubbles from the coolant, and can eliminate various problems that may occur in the cooling water system 30 due to the mixing of minute bubbles. Can be provided.

(Second Embodiment)
FIG. 4 shows a schematic configuration of a main part of an engine cooling system according to the second embodiment of the present invention.

  In the present embodiment, the gas collection tube referred to in the present invention is mounted in the middle of a coolant hose that constitutes a part of a sealed coolant passage, and the other configurations are the above-described first. This is the same as the embodiment. Therefore, the same constituent elements as those in the first embodiment will be described using the reference numerals of the corresponding constituent elements shown in FIGS. 1 to 3 and their illustration will be omitted.

  In the engine cooling system of the present embodiment, the gas collection pipe 51 forms a single coolant passage 54 together with the pair of hoses 52, 53. The gas collection pipe 51 and the pair of hoses 52, 53 are For example, it can be replaced with a radiator inlet hose 13. The gas collection pipe 51 and the pair of hoses 52 and 53 may be a passage other than the bypass passage 32 and may form a coolant passage provided in parallel to the radiator 12 and the reserve tank 20.

  In the present embodiment, the reserve tank 20 is connected to the top communication port 62p located in the vicinity of the coolant inlet 62i of the upper tank 62a of the radiator 62 by the reserve tank connection pipe 29a, and is also connected to the radiator 62 by the reserve tank connection pipe 29b. Connected to the lower tank 62b. The radiator 62 is of a known downflow type, and has a radiator core 62c between the upper tank 62a and the lower tank 62b.

  On the other hand, the gas collection pipe 51 is at least on the ceiling side so that the passage cross-sectional area increases toward the downstream side in the specific passage section 54s of the coolant passage 54 corresponding to the coolant passage in the radiator inlet side hose 13. The portion 51j has an inner wall surface 51a inclined in the vertical direction, and fine bubbles in the coolant passing through the coolant passage 31 are gathered on the downstream side in the bypass passage 32, which is a specific passage section, and on the upper side in the vertical direction. It is supposed to let you. In this case, the coolant passage 54 extends in a substantially horizontal direction at least inside the gas collection tube 51.

  Further, in the vicinity of the upper end in the vertical direction of the inner wall surface 51a of the gas collection pipe 51, it is connected to the middle of the reserve tank connection pipe 29a of the reserve tank 20 or the middle of the first communication pipe section 23 (branch portion) through the connection pipe 59. In addition, a communication port 51p communicating with the reserve tank 20 is formed. Of course, the connection pipe 59 may be separated from the second communication pipe part 24 and connected to another communication pipe part formed in the reserve tank 20 similarly to the first communication pipe part 23. The inner wall surface 51a of the gas collecting pipe 51 is inclined between the ceiling side portion 51j of the specific passage section 54s and the substantially horizontal downstream ceiling wall surface 51k with an inclination angle θ2 of the ceiling side portion 51j with respect to the inner bottom surface of the upper tank 12a. A steeply inclined surface 51h that has a sufficiently large inclination angle and steeply slopes in the opposite direction to the ceiling side portion 51j.

  Also in the present embodiment, in the gas collection pipe 51 that forms the specific passage section 54s that is a part of the coolant passage 31, bubbles in the coolant are on the downstream side in the specific passage section 54s and on the upper side in the vertical direction. It is integrated into a large bubble while gathering, and reaches the reserve tank 20 side with a bubble size that allows easy gas-liquid separation through the communication port 51p of the gas collection tube 51. Provided is an engine cooling system capable of improving the cooling efficiency of the engine 11 by efficiently separating the bubbles from the coolant and eliminating various problems that may occur in the cooling water system 30 due to the mixing of micro bubbles. be able to.

  Moreover, in this embodiment, since the gas collection pipe 51 is attached in the middle of the radiator inlet side hose 13 (coolant hose) constituting a part of the sealed coolant passage 31, the existing complete The gas collection pipe 51 can be easily added to the sealed engine cooling system to improve the gas-liquid separation performance, and the components constituting the gas collection pipe 51 can be shared with other engines. it can.

(Third embodiment)
FIG. 5 shows a schematic configuration of a radiator in the engine cooling system according to the third embodiment of the present invention. In the present embodiment, the present invention is applied to an engine cooling system including a crossflow type radiator, and other configurations are the same as those in the first embodiment. Constituent elements similar to those described with reference to the corresponding constituent elements shown in FIGS.

  The engine cooling system according to the present embodiment includes a cross-flow type radiator 72 instead of the down-flow type radiator 12 according to the first embodiment.

  The radiator 72 includes an inlet-side radiator tank 72a that introduces the coolant that has passed through the water jacket 11w of the engine 11, an outlet-side radiator tank 72b that returns the coolant after cooling by heat exchange to the engine 11 side, and the inlet-side radiator tank 72b. And a cross flow type (cross flow type) radiator core 72c disposed between the radiator tank 72a and the outlet side radiator tank 72b. Here, the radiator core 72c is integrally coupled to a plurality of cooling tubes 72ct through which cooling liquid distributed from the upper tank 72a passes in a substantially horizontal direction and the cooling tubes 72ct, as schematically shown in part in FIG. The plurality of cooling fins 72cf.

  In the present embodiment, in the coolant passage 31 passing through the inlet-side radiator tank 72a of the radiator 72, in the substantially vertical specific passage section 31s located on one side in the horizontal direction of the radiator core 12c, one of the inlet-side radiator tank 72a is provided. A gas collection tube 81 is constituted by the part.

  Further, the inner wall surface 81a of the gas collection pipe 81 constituted by the inlet side radiator tank 72a is inclined at least in the horizontal direction outward at the upper part of the side wall 81r on the horizontal direction outer side.

  Specifically, the inner wall surface 81a of the gas collecting pipe 81 has a passage cross-sectional area that increases toward the downstream side in the specific passage section 31s located in the inlet side radiator tank 72a of the radiator 72 in the coolant passage 31. As described above, at least the outer wall surface portion 81j is inclined to one side in a substantially horizontal direction opposite to the cross flow direction of the coolant, and fine bubbles in the coolant passing through the radiator tank 72a of the radiator 72 are removed. The specific passage section 31s is gathered downstream and vertically upward.

  In addition, a communication port 81p that communicates with the gas-liquid separation chamber 25 in the reserve tank 20 through the reserve tank connection pipe 29a is formed near the upper end in the vertical direction of the inner wall surface 81a of the gas collection pipe 81. Further, the inlet-side radiator tank 72a of the radiator 72 constitutes a gas collecting pipe 81 at an upper end portion in the extending direction extending in a substantially vertical direction on one side of the radiator core 72c, and the inlet-side radiator The upper end inner wall surface 81k of the tank 72a is slightly inclined so as to be positioned on the upper side in the vertical direction as it is closer to the communication port 81p.

  In this case, a relatively long specific passage section 31s can be easily secured in the inlet-side radiator tank 72a of the cross-flow type radiator 72 (particularly above the coolant inlet 72i), and even fine bubbles in the coolant can be specified. While gathering at the downstream side in the passage section 31s and the upper side in the vertical direction, it gradually increases in size and easily reaches the reserve tank 20 through the communication port 81p of the gas collection pipe 81 in a state where gas-liquid separation is easy. To do. Therefore, even if fine bubbles are mixed in the coolant in the inlet-side radiator tank 72a, the coolant is circulated in the cooling water system 30 by collection in the gas collection pipe 81 and gas-liquid separation in the reserve tank 20. Fine bubbles are reliably removed from the coolant.

  Also in the present embodiment, in the gas collecting pipe 81 that forms the specific passage section 31s that is a part of the coolant passage 31, bubbles in the coolant are on the downstream side in the specific passage section 31s and on the upper side in the vertical direction. It is integrated into a large bubble while gathering, and reaches the reserve tank 20 side with a bubble size that allows easy gas-liquid separation through the communication port 81p of the gas collection tube 81. Provided is an engine cooling system capable of improving the cooling efficiency of the engine 11 by efficiently separating the bubbles from the coolant and eliminating various problems that may occur in the cooling water system 30 due to the mixing of micro bubbles. be able to.

  In each of the above-described embodiments, only one gas collecting tube is provided in the cooling water system 30, but it goes without saying that a plurality of gas collecting tubes can be provided as long as a differential pressure across the front and rear can be ensured. In the present invention, it is preferable that the reserve tank constitutes a part of the coolant passage. However, when the reserve tank is used in combination with a gas collecting pipe that forms a part of the coolant passage, the reserve tank is provided with a pressure regulating valve. As long as it has a cap and has an internal air reservoir and a liquid reservoir, the coolant need not always flow.

  As described above, according to the present invention, in the gas collecting pipe forming the specific passage section of the coolant passage, the bubbles in the coolant are integrated while gathering on the downstream side and the vertical upper side in the specific passage section. It changes into large bubbles and reaches the reserve tank side with a bubble size that allows easy gas-liquid separation through the communication port of the gas collection tube, so that fine bubbles mixed in the cooling liquid can be efficiently removed from the cooling liquid. By separating, it is possible to increase the cooling efficiency of the engine, and it is possible to provide an engine cooling system that can eliminate various problems that may occur in the cooling water system 30 due to the inclusion of microbubbles. It is useful for general engine cooling systems suitable for gas-liquid separation of bubbles and cooling liquid in the cooling liquid when the cooling liquid is forcibly circulated in a sealed cooling water system. .

1 Engine cooling system 11 Engine (internal combustion engine)
11w Water jacket 12; 62; 72 Radiator 12a Upper tank (Radiator tank)
12c; 62c; 72c Radiator core 12i; 62i; 72i Coolant inlet 13 Radiator inlet side hose 14 Radiator outlet side hose 15 Water pump 16 Thermostat 20 Reserve tank 20a Liquid reservoir 20b Air reservoir 25 Gas-liquid separation chamber 29a, 29b Reserve Tank connection piping 30 Cooling water system 31; 54 Coolant passage 31d Downstream passage section 31e Opening 31s; 54s Specific passage section 31u Upstream passage section 41; 51; 81 Gas collection pipe 41a; 51a; 81a Inner wall surface 41j; 51j Ceiling Side portion 41k Downstream ceiling wall surface 41n Upstream ceiling wall surface 41p; 51p; 81p Communication port 52, 53 Hose 59 Connection pipe 72a Inlet side radiator tank 81j Outer wall surface portion 81k Upper end inner wall surface 81r Side wall

Claims (8)

A sealed cooling water system that forcibly circulates the engine coolant through a sealed coolant passage, a radiator that discharges the heat of the coolant by heat exchange with air, and a liquid that stores a part of the coolant inside An engine cooling comprising: a reservoir and an air reservoir located above the liquid reservoir, and a reserve tank that changes a storage amount of the coolant according to a change in volume of the coolant in the cooling water system A system,
The cooling liquid passage has an inner wall surface that is inclined so that the passage cross-sectional area increases toward the downstream side in the specific passage section, and collects bubbles in the cooling liquid on the downstream side and the upper side in the vertical direction in the specific passage section. Equipped with a gas collecting tube,
An engine cooling system characterized in that a communication port communicating with the inside of the reserve tank is formed in the vicinity of the upper end in the vertical direction of the inner wall surface of the gas collection pipe.   The reserve tank has a gas-liquid separation chamber for introducing and discharging a part of the cooling liquid during the forced circulation and for separating bubbles in the cooling liquid from the introduced cooling liquid. The engine cooling system according to claim 1. The radiator includes a radiator tank that introduces the coolant, and a radiator core that allows the coolant distributed from the radiator tank to pass through;
The engine cooling system according to claim 2, wherein the gas collection pipe is constituted by a part of the radiator tank. The radiator tank constitutes an upper tank extending in a substantially horizontal direction above the radiator core, and the radiator core has a downflow type tube,
The engine cooling system according to claim 3, wherein the inner wall surface of the gas collecting pipe formed by a part of the radiator tank is inclined in the vertical direction at least at a ceiling side portion.   5. The engine cooling system according to claim 4, wherein the radiator tank has a downstream ceiling wall surface inclined in a direction opposite to the specific passage section in a passage section downstream of the specific passage section. .   Inside the radiator tank, an upstream passage section that guides the coolant flowing into the radiator tank to the specific passage section, a downstream passage section that passes the coolant that has passed through the specific passage section, and the specific passage section And a plurality of openings for distributing the coolant from each of the upstream passage section, the downstream passage section, and the specific passage section to the radiator core side. The engine cooling system according to claim 4 or 5. The radiator tank is constituted by an inlet-side radiator tank located on one side in the horizontal direction of the radiator core, and the radiator core has a cross flow type tube,
The said inner wall surface of the said gas collection pipe comprised by the said inlet side radiator tank inclines to the horizontal direction outer side at least at the upper part of the side wall of a horizontal direction outer side. The engine cooling system described.   The engine cooling system according to claim 2, wherein the gas collection pipe is mounted in the middle of a coolant hose that constitutes a part of the sealed coolant passage.

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