JP2013060854A - Engine cooling device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control or prevent the occurrence of strain in each tube 8d of a radiator 8, when a coolant the temperature of which is increased, for example, during a warming-up of an engine 2, begins to enter the radiator 8, in an engine cooling device with the radiator 8 and electric fan 12.SOLUTION: A control unit 20 makes the heat generated from the engine 2 blow the radiator 8 by operating the electric fan 12 in the reverse rotational direction at the warming-up of the engine 2.

Description

  The present invention relates to an engine cooling device, and more particularly to a configuration including an electric fan for forcibly supplying wind to a radiator.

  A recent engine cooling apparatus includes a radiator for cooling a coolant of a water-cooled engine and an electric fan for forcibly supplying wind to the radiator.

  The radiator is configured to include a pair of upper and lower or left and right tanks and a heat exchange core. The heat exchange core has a configuration in which corrugated fins are provided on a number of tubes for circulating coolant connected between a pair of tanks.

  The electric fan is activated when the coolant temperature in the water jacket of the engine becomes equal to or higher than a predetermined threshold (for example, engine warm-up completion temperature) by the control system, for example. The electric fan is generally disposed between the radiator and the engine. When the electric fan is operated in the positive rotation direction, a negative pressure is generated between the radiator and the radiator so as to draw wind from the front of the radiator to the radiator. Act on.

  In general, when the engine is cold started, the thermostat provided in the coolant circulation path is closed, so that the coolant in the water jacket of the engine is not allowed to flow into the radiator. In this state, the coolant quickly rises in the water jacket of the engine.

  When the thermostat opens as the coolant in the water jacket rises, the high-temperature coolant raised in the engine water jacket flows into the radiator. The coolant that has flowed into the radiator is cooled by heat exchange with the outside air supplied by the electric fan. The coolant cooled by the radiator is returned to the engine.

  By the way, when the thermostat starts to open as the temperature of the coolant in the water jacket rises, when the high temperature coolant in the water jacket starts to flow into the radiator, in the initial stage of the inflow, A phenomenon may occur in which the high-temperature coolant flows evenly into some of the many tubes.

  When such a phenomenon occurs, the tube through which the high-temperature coolant flows is thermally expanded, but the tube without the high-temperature coolant does not expand, so that a large stress acts on each tube to cause distortion. Is likely to occur. Especially when the outside air temperature is low such as in winter, the viscosity of the coolant is reduced immediately after the high-temperature coolant flows into the radiator because the entire radiator is cold during engine warm-up. Therefore, the fluidity of the cooling liquid is lowered, and the above-described phenomenon of unevenness of the cooling liquid is likely to occur.

  By the way, in Patent Document 1, for example, in order to prevent thermal distortion from becoming noticeable between the upper and lower tanks and the left and right side plates in the radiator, for example, a shielding plate is installed on both sides of the engine. It is described that a wind guide plate that guides the traveling wind that has passed through the radiator to the left and right side plates is formed on the front end side of the plate.

  Further, for example, in Patent Document 2, the flow of the traveling wind that flows into the engine room is obstructed by rotating the electric fan in the reverse direction when the vehicle interior heater is requested in a situation where the warm-up of the internal combustion engine is insufficient. It is stated that you are going to try.

  Further, for example, in Patent Document 3, when the water temperature is equal to or lower than t3 and the supercharging pressure is higher than the set pressure p1, the electric fan is reversely rotated to prevent the traveling wind from flowing into the engine room. It is described that.

No. 05-17379 Japanese Patent Application Laid-Open No. 08-232658 Japanese Patent Laid-Open No. 07-11954

  The conventional example according to Patent Document 1 described above is designed to prevent thermal distortion from occurring in the radiator. As described above, “as the thermostat starts to open during engine warm-up, the temperature increases. There is no description that points out the problem of “distortion occurs in the radiator at the initial stage when the heated coolant begins to flow into the radiator”. Therefore, as a matter of course, Patent Document 1 does not describe or suggest a technical idea for solving the above-described problem. In addition, in the case of Patent Document 1, a shielding plate is purposely installed on both sides of the engine, and there is a concern that the equipment cost increases.

  In addition, although Patent Documents 2 and 3 describe that the electric fan is reversely rotated, the conditions and the purpose idea for reversely rotating the electric fan are different from the present invention.

  In view of such circumstances, the present invention provides an engine cooling device including a radiator for cooling a coolant of a water-cooled engine and an electric fan for forcibly supplying wind to the radiator. The purpose of the present invention is to suppress or prevent the occurrence of distortion in each tube of the radiator when the cooling liquid whose temperature is increased in (1) starts to flow into the radiator.

  An engine cooling device according to the present invention includes an internal passage of coolant provided inside the engine, an external passage for taking out the coolant in the internal passage and then returning it to the outside, and installed in the external passage and from the engine A radiator disposed in front of the vehicle, a water pump for flowing a coolant, an electric fan disposed between the radiator and the engine and supplying wind to the radiator, and And a controller that controls the operation, wherein the controller operates the electric fan in a reverse rotation direction when the engine is warmed up.

  In this configuration, during the warm-up of the engine, the coolant that is heated by the operation of the engine does not flow into the radiator, so the heat of the coolant that is heated by the engine is not transmitted to the numerous tubes that are provided in the radiator. .

  In such a situation, when the electric fan is operated in the reverse rotation direction, wind that flows in the opposite direction to the case where the electric fan is operated in the normal rotation direction is generated. That is, the heat generated from the engine is drawn into the radiator by the electric fan, so that hot air is supplied to the radiator. Thereby, many tubes in a radiator are warmed uniformly.

  Thereafter, for example, when the engine warm-up is completed, the coolant that has been heated in the engine starts to flow into the radiator, but at the initial stage of the inflow, the temperature-warmed coolant is temporarily increased in the radiator. Even if a phenomenon occurs in which some of the tubes flow unevenly, the temperature rise of the tube into which this high-temperature coolant flows is compared to the case where the radiator is not preheated as in the conventional example. And become smaller.

  Therefore, the difference between the amount of thermal expansion of the tube into which the high-temperature coolant flows and the amount of thermal expansion of the tube into which the high-temperature coolant does not flow can be small. Stress is less likely to act and distortion is less likely to occur.

  Preferably, the control unit determines whether or not the engine needs to be warmed up when the engine is started, and the ambient temperature in the vicinity of the engine during the warming up of the engine is a predetermined temperature. The second determination unit that determines whether or not the above is determined, and the first determination unit determines that the warm-up is necessary, and the second determination unit determines that the ambient temperature in the vicinity of the engine is equal to or higher than a predetermined temperature. An execution unit that executes a process of operating the electric fan in the reverse rotation direction.

  Here, since the configuration of the control unit is specified in detail, an embodiment for carrying out the present invention becomes clear.

  Preferably, the external passage includes a coolant take-out path for allowing the coolant discharged from the internal passage to flow into the radiator, and a coolant return for returning the coolant that has passed through the radiator to the internal passage. And a radiator bypass path connected to bypass the radiator to the coolant take-out path and the coolant return path, and in the coolant return path, more than the connection portion with the radiator bypass path. A control valve that opens when the coolant temperature becomes equal to or higher than the warm-up completion temperature of the engine is provided near the radiator.

  Here, the configuration of the external passage is specified, and the timing for operating the electric fan in the reverse rotation direction is specified.

  In this configuration, since the control valve is closed while the engine is warming up, the coolant heated in the internal passage of the engine is returned from the coolant take-out passage to the internal passage through the radiator bypass passage and the coolant return passage. It comes to be. When the engine warm-up is completed, the coolant that has been heated in the internal passage of the engine is diverted from the coolant take-out passage to the radiator bypass passage and the radiator.

  As a result, a part of the high-temperature coolant is returned from the radiator bypass passage to the internal passage through the coolant return passage, and further, a part of the high-temperature coolant is circulated through the radiator before the coolant return. It will be returned to the internal passage through the road.

  From this, it becomes clear that the timing when the control unit operates the electric fan in the reverse rotation direction is set when the control valve is closed, that is, before the control valve is opened. .

  Preferably, the radiator and the electric fan are surrounded by an air guide member.

  In this configuration, when the electric fan is operated in the reverse rotation direction, the wind drawn from the engine side is guided to a wide area on the rear surface of the radiator through the inside of the air guide member, so that it is difficult to escape to the periphery of the radiator. . As a result, it is possible to efficiently blow wind having heat generated from the engine side to almost all of the many tubes in the radiator.

  The present invention relates to an engine cooling device including a radiator for cooling a coolant of a water-cooled engine and an electric fan for forcibly supplying wind to the radiator, and the coolant heated in the engine When the gas begins to flow into the radiator, it is possible to suppress or prevent the occurrence of distortion in each tube of the radiator.

  Therefore, according to the present invention, it is possible to contribute to improvement of durability and reliability of the radiator.

It is the figure which showed typically the front part of the vehicle carrying the engine cooling device which concerns on this invention from the side. It is a front view which shows the radiator of FIG. It is a figure which shows the structure of the engine cooling device of FIG. 1, and has shown the coolant flow during engine warm-up. It is a figure which shows the structure of the engine cooling device of FIG. 1, and has shown the coolant flow after engine warm-up completion. FIG. 5 is an explanatory diagram showing a state when the electric fan is rotated forward after the engine warm-up is completed in the engine cooling device of FIGS. 3 and 4. FIG. 5 is an explanatory diagram showing a state when an electric fan is rotated in reverse during engine warm-up in the engine cooling device of FIGS. 3 and 4.

  BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the accompanying drawings.

  1 to 6 show an embodiment of the present invention. As shown in FIG. 1, a water-cooled engine 2 is mounted in an engine room in front of the vehicle 1. The engine 2 is provided with an intake system 3 for sucking outside air and an exhaust system 4 for discharging exhaust gas.

  Inside the engine 2, a water jacket 5 (see FIG. 3) is provided as an internal passage for circulating the coolant. The coolant heated by the water jacket 5 of the engine 2 is cooled by the radiator 8. As is well known, the coolant is an antifreeze such as an aqueous solution of ethylene glycol.

  The radiator 8 is disposed in front of the engine 2 in the engine room. As is well known, the radiator 8 exchanges heat between the coolant of the water-cooled engine 2 and the outside air. As shown in FIG. 2, the radiator 8 includes a pair of upper and lower tanks 8a and 8b, a heat exchange core 8c, and the like. I have. As is well known, the heat exchange core 8c has a configuration in which corrugated fins 8e are provided on a number of tubes 8d for circulating coolant connected between a pair of tanks 8a and 8b.

  The water jacket 5 and the radiator 8 are connected to a cooling liquid take-out path 6 and a cooling liquid recirculation path 7 so that the cooling liquid can flow between them.

  The coolant take-out path 6 communicates and connects the discharge port of the water jacket 5 in the engine 2 and the coolant introduction port of the radiator 8. The coolant reflux path 7 connects the coolant discharge port of the radiator 8 and the coolant reflux port of the water jacket 5 of the engine 2 in communication with each other.

  A radiator bypass path 9 for bypassing the radiator 8 is connected to the coolant take-out path 6 and the coolant return path 7. The cooling liquid take-out path 6, the cooling liquid recirculation path 7, and the radiator bypass path 9 correspond to the external path described in the claims.

  As shown in FIG. 3, a thermostat 10 is installed closer to the radiator 8 (upstream side in the coolant flow direction) than the connection portion with the radiator bypass passage 9 in the coolant recirculation passage 7.

  The thermostat 10 is called a temperature-sensitive automatic opening / closing valve, and automatically opens when the coolant temperature in the vicinity of the temperature sensing part becomes equal to or higher than the engine warm-up completion temperature, for example. When the thermostat 10 is closed, the coolant is not allowed to flow into the radiator 8 but is returned to the water jacket 5 of the engine 2 via the radiator bypass 9. On the other hand, when the thermostat 10 is opened, the coolant passes through the radiator 8 and then flows back to the water jacket 5 of the engine 2.

  A water pump 11 is installed in the coolant recirculation path 7 closer to the engine 2 (downstream in the coolant flow direction) than the connection portion with the radiator bypass path 9. The water pump 11 is a mechanical water pump that is driven by the rotational power of a crankshaft (not shown) of the engine 2.

  An electric fan 12 is disposed between the radiator 8 and the engine 2 in the engine room. The electric fan 12 is not shown in detail as is well known, but forcibly supplies wind to the radiator 8 by rotating the fan with a motor. The operation of the electric fan 12 is controlled by the control device 20.

  A fan shroud 13 as a wind guide member is installed between the rear surface of the radiator 8 and the electric fan 12. The fan shroud 13 is installed so as to surround the radiator 8 and the electric fan 12, and is provided to guide the wind generated when the electric fan 12 rotates backward to a wide area on the rear surface of the radiator 8. It is done.

  The control device 20 is, for example, an engine control computer (E / G_ECU). Although not shown in detail, the control device 20 has a known configuration including a CPU (central processing unit), a ROM (program memory), a RAM (data memory), a backup RAM (nonvolatile memory), and the like. .

  The ROM stores various control programs, maps that are referred to when the various control programs are executed, and the like. The CPU executes arithmetic processing based on the various control programs and maps stored in the ROM. The RAM is a memory for temporarily storing calculation results in the CPU, data input from each sensor, and the like. The backup RAM is a nonvolatile memory for storing data to be saved when the engine 2 is stopped. It is memory.

  The controller 20 receives at least detection outputs from the engine water temperature sensor 31, the outside air temperature sensor 32, and the engine room temperature sensor 33. The control device 20 controls the operation of the electric fan 12 based on input information from the sensors 31 to 33.

  The engine water temperature sensor 31 is installed near the engine 2 in the coolant take-out path 6 and detects the coolant temperature at the installation location (hereinafter simply referred to as engine coolant temperature). The outside air temperature sensor 32 detects the temperature outside the vehicle. The engine room temperature sensor 33 is installed in the vicinity of the exhaust system 4 in the engine room, and detects the ambient temperature (hereinafter simply referred to as engine room temperature) at the installation location.

  For example, when the coolant temperature of the engine 2 becomes equal to or higher than a predetermined threshold (for example, warm-up completion temperature) by the control system, the control device 20 operates the electric fan 12 in the normal rotation direction. As a result, the electric fan 12 generates a negative pressure with the radiator 8 and acts to draw wind into the radiator 8 from the front of the radiator 8 by the negative pressure.

  As described above, the engine includes the water jacket 5, the coolant discharge path 6, the coolant return path 7, the radiator 8, the radiator bypass path 9, the thermostat 10, the water pump 11, the electric fan 12, and the control device 20. An engine cooling device is configured.

  Next, the basic operation of the engine cooling device will be described.

  When the engine 2 is cold-started, that is, when the coolant temperature near the thermostat 10 is lower than the engine warm-up completion temperature Th when the engine 2 is started, the thermostat 10 is closed. The coolant of the water jacket 5 of the engine 2 is driven by the driven water pump 11 through the coolant take-out path 6, the radiator bypass path 9, and the coolant recirculation path 7 as shown by solid arrows in FIG. 3. Return to the jacket 5. In such a circulation process of the coolant, the coolant in the engine 2 and the water jacket 5 is quickly heated by the heat of the combustion chamber of the engine 2.

  Then, when the coolant temperature in the vicinity of the thermostat 10 in the heater circulation path 3 becomes equal to or higher than the engine warm-up completion temperature Th, the thermostat 10 opens, so that the coolant in the water jacket 5 of the engine 2 is taken out of the coolant. The flow is diverted from the path 6 to both the radiator bypass path 9 and the radiator 8 with an appropriate distribution.

  In this case, the coolant in the water jacket 5 of the engine 2 passes through the coolant take-out path 6, the radiator bypass path 9, and the coolant recirculation path 7 as shown by the solid line arrows in FIG. At the same time, the flow returns to 5 and flows into the radiator 8 from the cooling liquid take-out path 6 as indicated by a one-dot chain line arrow in FIG. The hot coolant flowing into the radiator 8 exchanges heat with the outside air, and then returns to the water jacket 5 through the heater circulation path 3. In such a situation, the coolant heated by the engine 2 is cooled by the radiator 8, so that the coolant temperature of the water jacket 5 is maintained within a predetermined temperature range.

  The control device 20 in this embodiment performs a process of operating the electric fan 12 in the reverse rotation direction when the engine 2 is warmed up, that is, when the coolant heated by the engine 2 is not flowing into the radiator 8. To do.

  When this process is performed, the heat-generated wind emitted from the engine 2 is blown to the radiator 8, and the radiator 8 is warmed by the hot air. This process is referred to as a pre-warming process of the radiator 8, for example.

  Specifically, the control device 20 includes a first determination unit that determines whether or not the engine 2 needs to be warmed up when the engine 2 is started, and the ambient temperature in the vicinity of the engine 2 is predetermined during the warming up of the engine 2. A second determination unit that determines whether the temperature is equal to or higher than the temperature, and the first determination unit determines that the warm-up is necessary, and the second determination unit determines that the ambient temperature in the vicinity of the engine 2 is equal to or higher than a predetermined temperature. An execution unit that executes a process of operating the electric fan 12 in the reverse rotation direction when it is determined that the electric fan 12 is present.

  The first determination unit, the second determination unit, and the execution unit are function implementation elements necessary for control by the control device 20, and function as an internal configuration of the control device 20 in order to make the explanation in this embodiment easy to understand. They are only divided.

  Here, when the engine 2 is cold-started, the control device 20 determines that the temperature in the engine room is equal to or higher than a predetermined temperature due to combustion heat or exhaust heat from the engine 2 until the warm-up of the engine 2 is completed. When it is determined that the electric fan 12 has been reached, the electric fan 12 is operated in the reverse rotation direction as shown in FIG.

  Then, when the warm-up of the engine 2 is completed, the control device 20 stops the electric fan 12 operating in the reverse rotation direction. When the engine coolant temperature (detected output of the engine water temperature sensor 31) becomes equal to or higher than the predetermined temperature after the warm-up of the engine 2 is completed, the control device 20 moves the electric fan 12 in the forward rotation direction as shown in FIG. Operate. When the engine coolant temperature is lowered by the electric fan 12 and the engine coolant temperature becomes lower than a predetermined temperature, the control device 20 controls the electric fan 12 to stop.

  As described above, in the embodiment to which the present invention is applied, the coolant that has been heated in the water jacket of the engine 2 due to the thermostat 10 being closed, for example, during engine warm-up, is supplied to the radiator 8. When the electric fan 12 is not flowing in, the electric fan 12 is operated in the reverse rotation direction so that the heat released from the engine 2 and the exhaust system 4 is blown to the radiator 8, so that a large number of tubes 8 d of the radiator 8 are provided. It will be warmed up uniformly.

  In this way, if all of the many tubes 8d in the radiator 8 are warmed by the heat of the engine 2 before the high-temperature coolant flows into the radiator 8, the warm-up of the engine 2 progresses and the thermostat 10 When the coolant heated by the engine 2 starts to flow into the radiator 8 as the valve starts to open, the following occurs.

  That is, even if a phenomenon occurs in the initial stage of inflow of the coolant to the radiator 8, even if a phenomenon occurs in which the heated coolant is biased and flows into a part of the many tubes 8 d in the radiator 8. The temperature rise of the tube 8d into which the coolant flows is smaller than in the case where the radiator 8 is not warmed in advance as in the conventional example.

  Therefore, the difference between the amount of thermal expansion of the tube 8d into which the high-temperature coolant flows and the amount of thermal expansion of the tube 8d into which the high-temperature coolant does not flow can be small. It becomes difficult for large stress to act and distortion to occur. As a result, the durability and reliability of the radiator 8 can be improved.

  By the way, when the outside air temperature is low as in the winter season, the entire radiator 8 is cooled. Therefore, as described above, the radiator 8 that has been cooled in the initial stage starts to flow into the radiator 8 at a high temperature. When a high-temperature coolant flows in, the coolant temperature decreases, the viscosity increases, and the fluidity tends to decrease. For this reason, it is considered that the above-described phenomenon of unevenness of the coolant is likely to occur.

  However, since the entire radiator 8 is relatively warm when the outside air temperature is high as in the summer, the high temperature of the warm radiator 8 is increased in the initial stage where the high-temperature coolant starts to flow into the radiator 8 as described above. Even if the cooling liquid flows in, the viscosity hardly changes, so that it is considered that the above-mentioned phenomenon of unevenness of the cooling liquid hardly occurs.

  Considering these matters, for example, when the outside air temperature (the detection output from the outside air temperature sensor 32) is in a predetermined temperature range (winter temperature), the radiator 8 is subjected to the pre-warming process, and the outside air temperature ( When the detection output from the outside air temperature sensor 32 is within a predetermined temperature range (summer temperature), it is possible not to perform the pre-warming-up process of the radiator 8.

  In this way, it is possible to make it difficult to generate distortion in each tube 8d of the radiator 8 in the initial stage of the coolant flowing into the radiator 8 in winter, and in the summer, the pre-warming process of the radiator 8 is performed. It can be said that wasteful consumption of electrical energy required for the operation of the electric fan 12 can be avoided, which contributes to an improvement in fuel consumption, and can also avoid unnecessary generation of the operation sound of the electric fan 12.

  In addition, this invention is not limited only to the said embodiment, It can change suitably in the range equivalent to the claim and the said range.

  (1) In the above-described embodiment, the case where the multi-cylinder engine 2 is mounted in the horizontal position is described as an example. However, the present invention can also be applied when the engine 2 is mounted in the vertical position. Is possible.

  (2) In the above embodiment, the case where the exhaust system 3 is arranged in front of the engine 2 is taken as an example, but the arrangement of the exhaust system 3 is not particularly limited.

  (3) In the above embodiment, the case where the water pump 11 is a mechanical type is described as an example, but the water pump 11 can be an electric type.

  In that case, for example, if the electric water pump 11 is deactivated when the coolant temperature is lower than the warm-up completion temperature of the engine 2, the coolant stops without flowing in the water jacket 5 of the engine 2. Therefore, it is advantageous for further promoting the temperature rise of the coolant.

  (4) In the above embodiment, the case where the thermostat 10 is used as the control valve described in the claims is taken as an example, but it can be changed to, for example, an electromagnetic valve or an electric valve.

  In that case, the control device 20 needs to be configured to control the electromagnetic valve or the motor-operated valve to the open side or the closed side in accordance with the change in the coolant temperature (the detection output of the engine water temperature sensor 31).

  Note that when the thermostat 10 is used as a control valve, it is less expensive than the electromagnetic valve or the motor operated valve and a control system is unnecessary, which is advantageous in reducing the equipment cost. On the other hand, when the solenoid valve or the motor-operated valve is used as the control valve, the timing of opening / closing the solenoid valve or the motor-operated valve can be arbitrarily set. Depending on the situation, the degree of freedom is expanded, for example, the timing of the coolant flow into the radiator 8 can be controlled arbitrarily and accurately.

  (5) In the above embodiment, the radiator 8 is exemplified as a type including a pair of upper and lower tanks 8a and 8b. However, a radiator including a pair of left and right tanks may be used.

  INDUSTRIAL APPLICABILITY The present invention can be suitably used for an engine cooling device including a coolant flow passage (5, 6, 7, 9), a radiator (8), an electric fan (12), and the like.

1 vehicle 2 engine 5 water jacket (internal passage)
6 Coolant outlet (part of external passage)
7 Coolant return path (part of external path)
8 Radiator 8d Radiator tube 9 Radiator bypass (part of external passage)
DESCRIPTION OF SYMBOLS 10 Thermostat 11 Water pump 12 Electric fan 20 Control apparatus 31 Engine water temperature sensor 32 Outside air temperature sensor 33 Engine room internal temperature sensor

Claims (4)

An internal passage of coolant provided in the engine, an external passage for taking out the coolant in the internal passage and then returning it, and a radiator installed in the external passage and disposed in front of the engine than the engine; A water pump for causing the coolant to flow, an electric fan disposed between the radiator and the engine and supplying air to the radiator, and a control unit for controlling the operation of the electric fan. ,
The engine cooling device, wherein the control unit operates the electric fan in a reverse rotation direction when the engine is warmed up. The engine cooling device according to claim 1, wherein
The controller is
A first determination unit for determining whether the engine needs to be warmed up when the engine is started;
A second determination unit that determines whether or not an ambient temperature in the vicinity of the engine is equal to or higher than a predetermined temperature during warming up of the engine;
Processing for operating the electric fan in the reverse rotation direction when the first determination unit determines that warm-up is necessary and the second determination unit determines that the ambient temperature in the vicinity of the engine is equal to or higher than a predetermined temperature. An engine cooling device comprising: an execution unit that executes The engine cooling device according to claim 1 or 2,
The external passage includes a coolant take-out path for allowing the coolant discharged from the internal passage to flow into the radiator, a coolant return path for returning the coolant that has circulated through the radiator to the internal passage, A radiator bypass path connected to bypass the radiator to the coolant outlet path and the coolant reflux path;
A control valve that opens when the coolant temperature becomes equal to or higher than the warm-up completion temperature of the engine is provided closer to the radiator than the connection portion with the radiator bypass passage in the coolant circulation passage. Engine cooling device. In the engine cooling device according to any one of claims 1 to 3,
The engine cooling apparatus, wherein the radiator and the electric fan are covered with an air guide member.

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