JP2010025009A - Cooling system and cooling method of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cooling system, a cooling method for internal combustion engine that prevents thermal damages by suppressing temperature rise within an engine room, by facilitating to take-in vehicle running-induced wind, while rotation of cooling fan is stopped, enables saving energy to be consumed for driving the cooling fan by reducing frequency of rotating the cooling fan, and furthermore easy to control. <P>SOLUTION: A cooling system is configured such that an openable and closable first shutter 12 is provided at a fan shroud 8, arranged in the rear part of a heat exchanger 6 for cooling a coolant of a vehicle-mounted engine 4 through heat exchange with open air, for directing the open air to a cooling fan 7, and an openable and closable second shutter 13 is provided at a ventilation portion 11 for taking-in the open air into an engine room of a vehicle without causing it to pass through the heat exchanger 6, and the open/close control of the first shutter 12 and the second shutter 13 is performed, using detection temperature Tcm of the coolant, open/close state of a passage to the heat exchanger 6 of the coolant by a temperature adjusting means 9, and ON/OFF signals of an electronic control fan clutch 7a for controlling rotation of the cooling fan 7. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a cooling system and a cooling method for an internal combustion engine mounted on a vehicle, and more specifically, by controlling the flow of traveling air around a cooling fan that takes in outside air, while suppressing temperature rise in an engine room. The present invention relates to a cooling system and a cooling method for an internal combustion engine that can reduce the rotation frequency of a cooling fan and save energy consumed by driving the fan.

  In a vehicle equipped with a water-cooled internal combustion engine (engine) that circulates cooling liquid inside the internal combustion engine (engine) and cools the coolant, water is supplied to the cylinder wall surface by a water pump in order to cool the internal combustion engine. When the temperature of this coolant is low, it is circulated to the water jacket without passing through the radiator by switching the flow path with a thermostat, and when the temperature of the coolant is high, it is routed through the radiator by switching the flow path of the thermostat. After cooling the coolant, it is circulated through the water jacket.

  This radiator is a heat exchanger that exchanges heat with the engine coolant by the outside air. The heat of the coolant is transferred to the outside air, and the temperature of the coolant decreases. The outside air that cools the radiator is supplied to the radiator by driving a cooling fan disposed behind the radiator when the vehicle is stopped, and by driving wind and cooling fan when the vehicle is traveling. Inhaled. This sucked outside air flows out of the vehicle through the opening of the under cover of the engine room.

  The cooling fans include an engine-driven cooling fan (engine-driven fan) that uses engine rotation as the driving force of the fan and an electric-type cooling fan (electric fan) that uses a DC motor. In this engine-driven cooling fan, a fan clutch such as a viscous fan clutch (auto fan coupling) or an electronically controlled fan clutch is provided between the rotating shaft of the engine and the temperature of the air passing through the radiator is detected. Based on this detected temperature, the clutch is turned on and off to control the rotation of the cooling fan.

  In the case of this viscous fan clutch, even when the coolant temperature is low and the cooling fan does not need to be driven with respect to the radiator, such as when the engine is cold-started, the clutch is not completely disengaged. The cooling fan is set to rotate about 100 revolutions, and outside air is sucked by the cooling fan to ventilate the engine room to suppress the temperature rise in the engine room.

  If an electronically controlled fan clutch (or an electric cooling fan) is used, the rotation to the cooling fan is controlled by electronic control so that the rotation speed is appropriate according to the engine coolant temperature and vehicle speed. The amount of transmission (or the amount of rotation of the electric motor) is adjusted. As a result, the cooling fan is driven at the necessary rotational speed only when it is necessary for cooling, thereby improving fuel efficiency, improving engine warm-up performance, and improving engine output. Even in this case, it is necessary to drive the cooling fan for ventilation of the engine room even if the temperature of the coolant does not rise.

  On the other hand, in order to control the flow of outside air in the vicinity of the radiator, a cooling system for an internal combustion engine is also proposed in which a shutter is provided and the opening and closing of the shutter is controlled at the vehicle speed and the temperature of the cooling water.

  For example, an electric fan is disposed between the radiator and the engine via a fan shroud that covers a part of the rear surface of the core portion of the radiator, and the first shutter is disposed in front of the fan shroud region covered with the fan shroud. A second shutter is disposed in front of the ventilation region not covered by the fan shroud, and the first shutter is closed when the vehicle speed is equal to or lower than a predetermined vehicle speed and the coolant temperature is equal to or lower than the predetermined temperature. There has been proposed an automobile in which the shutter is closed at a predetermined vehicle speed or lower and the first shutter and the second shutter are closed at a predetermined vehicle speed or higher and the coolant temperature is lower than a predetermined temperature ( For example, see Patent Document 1).

  In this automobile, the first shutter in the fan shroud area is closed when the temperature of the coolant is low, thereby ensuring the heating performance in winter and preventing the increase in vehicle air resistance due to the ventilation of the radiator, thereby improving fuel efficiency. ing. In addition, when the vehicle speed is below a predetermined vehicle speed such as idling, the second shutter disposed between the front grille and the radiator is closed, and the exhaust air sucked into the electric fan is reversed after colliding with the engine and is turned into the fan shroud. The problem is that the cooling efficiency is lowered because the air is blown back to the front surface of the condenser or radiator from the opening that is not covered.

  In addition, although it is used for cooling a fuel cell mounted on a vehicle, an opening that opens and closes depending on the wind pressure of the outside air that has passed through the radiator is provided in the fan shroud that connects the radiator body and the cooling fan. A radiator device for a fuel cell vehicle has been proposed in which the air volume passing through the radiator main body is increased to sufficiently cool the cooling medium, and the opening is closed to increase fan efficiency at low vehicle speeds (for example, Patent Document 2).

However, when the rotation of the cooling fan is stopped, it is easy to take in the traveling wind, the temperature inside the engine room can be suppressed to prevent heat damage, the frequency of rotation of the cooling fan is reduced, No suitable proposal has been made for the arrangement and control of the shutter that can save the energy consumed for driving the cooling fan.
JP 2000-130167 A JP 2005-199972 A

  The present invention has been made in view of the above situation, and its purpose is to make it easy to take in the traveling wind when the cooling fan is stopped, and to suppress the temperature rise in the engine room to cause heat damage. The internal combustion engine cooling system and cooling method can be reduced by reducing the frequency of rotating the cooling fan, saving energy consumed for driving the cooling fan, and having a simple control. It is to propose.

  An internal combustion engine cooling system for achieving the above object includes a heat exchanger for cooling a coolant of an internal combustion engine mounted on a vehicle by heat exchange with outside air, and the heat exchanger in the engine room of the vehicle. A ventilation section that takes in without passing through, a fan shroud that is arranged at the rear of the heat exchanger and guides the outside air to the cooling fan, and sucks in the outside air after passing through the heat exchanger surrounded by the fan shroud, An internal combustion engine cooling system comprising: a cooling fan using an electronically controlled fan clutch or an electric cooling fan; and a fan rotation control device that controls transmission of rotation of the internal combustion engine to the cooling fan. A first shutter that can be opened and closed at the portion, and a second shutter that can be opened and closed at the portion of the ventilation portion, and the first shutter and the second shutter. And a shutter opening / closing control means for controlling opening / closing of the shutter, and the shutter opening / closing control means includes a temperature adjusting means for opening / closing a temperature of the cooling liquid and a passage of the cooling liquid to the heat exchanger. The opening / closing control of the first shutter and the second shutter is performed using the open / closed state of the passage to the vehicle and the on / off signal of the electronically controlled fan clutch or the on / off signal of the driving of the electric cooling fan. Constitute.

  According to this configuration, when rotation of the cooling fan is stopped, on-rotation that rotates the cooling fan by facilitating taking in the traveling wind and suppressing the temperature rise in the engine room to prevent heat damage. Therefore, the arrangement of the first shutter and the second shutter can save energy consumed for driving the cooling fan.

  Also, the opening and closing of the first shutter and the second shutter are performed by opening and closing the temperature of the coolant of the internal combustion engine (engine) and the passage of the temperature adjusting means (thermostat etc.) to the heat exchanger (radiator etc.) of the coolant. The first shutter and the second shutter that accurately correspond to the situation of the vehicle and the internal combustion engine, using the state and the on / off signal for the electronically controlled fan clutch or the on / off signal for driving the electric cooling fan Can be controlled by a relatively simple device configuration and relatively simple control.

  In the internal combustion engine cooling system, in warm-up operation and low-load operation of the internal combustion engine, the electronically controlled fan clutch or the electric cooling fan is turned off to stop the driving of the cooling fan, and the shutter The opening / closing control means is configured to control to close the first shutter and the second shutter. The low load operation is to operate the internal combustion engine in a low torque state.

  According to this configuration, the driving of the cooling fan is stopped and the first shutter is stopped in a situation that requires warm-up such as low-load operation after engine startup, that is, in warm-up operation and low-load operation of the internal combustion engine. Is closed to prevent natural cooling air from passing through the heat exchanger, thereby avoiding cooling of the coolant. Further, the second shutter is closed to prevent ventilation by ventilation from the ventilation portion that does not pass through the heat exchanger into the engine room, thereby avoiding cooling of the internal combustion engine disposed in the engine room. By suppressing both this natural ventilation and ventilation, the warm-up performance of the internal combustion engine is improved.

  In the cooling system for an internal combustion engine, while the coolant passage to the heat exchanger is closed by the temperature adjusting means, the electronically controlled fan clutch or the electric cooling fan is turned off and the cooling fan is turned off. And the shutter opening / closing control means controls to open the first shutter and the second shutter.

  According to this configuration, the driving of the cooling fan is stopped until the temperature of the coolant rises after the warm-up operation of the internal combustion engine and the temperature adjusting means opens the coolant passage to the heat exchanger. At the same time, the first shutter is opened to generate natural ventilation of the cooling air passing through the heat exchanger, and the second shutter is also opened to ventilate the engine room from the ventilation portion that does not pass through the heat exchanger. To ventilate the engine room. The engine is cooled by both natural ventilation and ventilation, and the drive energy of the cooling fan is saved, and the temperature rise of the coolant is suppressed.

  In the cooling system for an internal combustion engine, a coolant passage to the heat exchanger is opened by the temperature adjusting means. If the coolant temperature is equal to or lower than a preset temperature, the electronically controlled fan clutch or The driving of the electric cooling fan is turned off to stop the driving of the cooling fan, and the shutter opening / closing control means controls to open the first shutter and close the second shutter. To do.

  According to this configuration, when the temperature of the coolant further increases and the coolant is cooled by the heat exchanger, the driving of the cooling fan is stopped. At the same time, the first shutter is opened to generate natural ventilation of cooling air passing through the heat exchanger, and the second shutter is closed to increase the differential pressure across the heat exchanger, thereby exchanging heat. The amount of natural ventilation passing through the vessel is increased to save the driving energy of the cooling fan, and the temperature rise of the coolant is suppressed.

  In the cooling system for an internal combustion engine, when the coolant passage to the heat exchanger is opened by the temperature adjusting means and the temperature of the coolant is higher than a preset temperature, the electronic control fan The clutch or electric cooling fan is turned on to drive the cooling fan, and the shutter opening / closing control means controls to close the first shutter and the second shutter.

  According to this configuration, when the temperature of the cooling liquid further rises and there is a strong demand for cooling the cooling liquid by the heat exchanger, the cooling fan is driven and the first shutter and the second shutter are mounted. The outside air passage is closed and concentrated in the cooling fan portion to perform forced ventilation, and an increase in the temperature of the coolant is suppressed by a large amount of cooling air passing through the heat exchanger. This prevents engine overheating.

  An internal combustion engine cooling method for achieving the above object includes a heat exchanger that cools a coolant of an internal combustion engine mounted on a vehicle by heat exchange with outside air, and the heat exchange between the outside air and the engine room of the vehicle. A ventilation section that takes in the air without passing through the heat exchanger, a fan shroud that is arranged at the rear of the heat exchanger and guides the outside air to the cooling fan, and the outside air that has passed through the heat exchanger surrounded by the fan shroud. An internal combustion engine cooling method comprising: a cooling fan using an electronically controlled fan clutch or an electric cooling fan that sucks in; and a fan rotation control device that controls transmission of rotation of the internal combustion engine to the cooling fan. A first shutter that can be opened and closed at the fan shroud portion and a second shutter that can be opened and closed at the ventilation portion are provided, and further, the first shutter and the second shutter are provided. And a shutter opening / closing control means for controlling opening / closing of the shutter, and the shutter opening / closing control means includes a temperature adjusting means for opening / closing a temperature of the cooling liquid and a passage of the cooling liquid to the heat exchanger. The opening / closing control of the first shutter and the second shutter is performed using an open / closed state of the passage to the vehicle and an on / off signal of the electronically controlled fan clutch or an on / off signal of driving the electric cooling fan. Features.

  According to this method, when rotation of the cooling fan is stopped, on-rotation that rotates the cooling fan by facilitating taking in the traveling wind and suppressing temperature rise in the engine room to prevent heat damage. The opening / closing control of the first shutter and the second shutter, which can save energy consumed for driving the cooling fan, can be performed by controlling the coolant temperature and the coolant heat exchanger ( By using the open / closed state of the passage to the radiator and the like and the on / off signal, it is possible to accurately correspond to the situation of the vehicle and the internal combustion engine with a relatively simple device configuration and relatively simple control.

  According to the cooling system and cooling method for an internal combustion engine according to the present invention, when the cooling fan is stopped, it is easy to take in the traveling wind and suppress the temperature rise in the engine room to prevent thermal damage. Thus, the frequency of rotating the cooling fan can be reduced to save energy consumed for driving the cooling fan.

  In addition, since the opening and closing of the first shutter and the second shutter are performed using the temperature of the coolant, the opening and closing state of the passage of the coolant to the heat exchanger, and the on / off signal for driving the cooling fan, Opening and closing control that accurately corresponds to the situation of the vehicle and the internal combustion engine can be performed with relatively simple control.

  DESCRIPTION OF EMBODIMENTS Hereinafter, a cooling system and a cooling method for an internal combustion engine according to an embodiment of the present invention will be described with reference to the drawings, taking a cooling system for a suction type internal combustion engine as an example.

  As shown in FIG. 1, in the engine cooling system 1 according to the first embodiment, an air conditioner condenser 5 is provided between the opening 3 in front of the vehicle 2 and the engine 4 so as to face the opening 3. A radiator (heat exchanger) 6, a cooling fan 7, and a fan shroud 8 that covers the back surface of the radiator 6 and the periphery of the cooling fan 7 are provided.

  The air conditioner condenser 5 is a condenser for an air conditioner (air conditioner) used in a vehicle, and cools and condenses (condenses) the refrigerant with outside air.

  The radiator 6 is a heat exchanger that exchanges heat between outside air and the coolant of the engine 4, and is formed by an upper tank in the upper part, a lower tank in the lower part, and a radiator core therebetween. Alternatively, it is formed by left and right tanks and a radiator core therebetween. The radiator core is formed by a thin pipe through which a cooling liquid such as a plate fin type or a corrugated fin type passes. When the coolant moves between the two tanks, it passes through the radiator core, and heat is exchanged with the outside air by applying cooling air of the outside air to the radiator core.

  The radiator 6 cools the coolant sent from the engine 4 via the radiator hose 6a by radiating the coolant in the radiator core, and returns the coolant whose temperature has decreased to the engine 4 via the radiator hose 6a. . There is also a heat exchanger called UCR in which the air conditioner condenser 5 and the radiator 6 are integrally formed.

  Further, a thermostat 9 is provided as temperature adjusting means for opening and closing the passage of the coolant to the radiator 6 in order to control the temperature of the coolant. The thermostat 9 is a thermostat such as a bellows type or a wax pellet type, and is attached to the outlet or inlet of the coolant of the engine 4. When the coolant temperature Tcm is lower than the preset valve opening temperature normal (70 ° C. to 80 ° C.) T 3, the thermostat 9 keeps the passage to the radiator 6 closed and increases the coolant temperature Tcm. Promote, improve warm-up performance, and prevent engine 4 from overcooling. Further, when the temperature Tcm of the coolant increases and reaches a preset valve opening temperature T3, the passage to the radiator 6 is opened, the coolant is supplied to the radiator 6 and cooled by the outside air to be cooled by the engine 4. Prevent overheating.

  The coolant passes through the water jacket on the cylinder wall surface of the engine 4 by the water pump 10 attached to the main body of the engine 4, and when the temperature Tcm of the coolant is low, the flow of the thermostat 9 switches the flow from the thermostat 9. It returns to the water pump 10 of the engine 4 via the heater core (heat exchanger) 14 and the water pump 10 which are heat sources for air conditioning. When the temperature Tcm of the coolant is high, the thermostat 9 is cooled by the thermostat 9 through the radiator 6 and then returned to the water pump 10 by switching the flow path of the thermostat 9. Even in this case, a part of the coolant returns from the thermostat 9 to the water pump 10 via the heater core 14.

  The cooling fan 7 sucks outside air from the opening 3 of the vehicle 2 and allows the air-conditioning condenser 5 and the radiator 6 to pass through. The cooling fan 7 is disposed between the radiator 6 and the engine 4. The cooling fan 7 is composed of an engine driving fan that uses engine rotation as a driving force. When the cooling liquid temperature Tcm is equal to or lower than a preset driving start temperature T4, the cooling fan 7 is turned off and the cooling liquid temperature Tcm is set in advance. When the temperature becomes higher than the set drive start temperature T4, the drive is turned on. In the case of an engine drive fan using the electronically controlled fan clutch 7a, the cooling fan 7 is turned on and off by turning on and off the electronically controlled fan clutch 7a. In the case of an electric fan that drives the cooling fan 7 with an electric motor, the electric motor is driven on and off.

  According to the present invention, the cooling fan 7 is configured such that when the vehicle travels and the coolant temperature Tcm is higher than a preset driving start temperature T4, forced ventilation by driving the cooling fan 7 is added to natural ventilation by the traveling wind. Then, the condenser 5 and the radiator 6 are cooled.

  Further, a fan shroud 8 is provided so as to cover the back surface of the radiator 6 and the periphery of the cooling fan 7 in order to guide outside air to the cooling fan 7. The outside of the fan shroud 8 serves as a ventilation portion 11 for taking outside air into the engine room of the vehicle without passing the air conditioning condenser 5 and the radiator 6 into the engine room of the vehicle.

  In the present invention, the fan shroud 8 is provided with a first shutter 12 which can be opened and closed, and a second shutter 13 which can be opened and closed is provided at a ventilation portion. Further, a shutter opening / closing control device (shutter opening / closing control means) 15a for performing opening / closing control of the first shutter 12 and the second shutter 13 is provided.

  The structure of the first shutter 12 according to the first embodiment is configured such that the rear surface of the inclined fan shroud 8 can be expanded in four directions as shown in FIGS. , The passage opened in four directions in FIG. The first shutter 12 is expanded and closed in four directions by an electric motor such as a tapping motor, but other direct acting mechanisms such as a solenoid, a hydraulic cylinder, a pneumatic cylinder, or the like may be used.

  The second shutter 13 is provided in a ventilation portion that takes outside air into the engine room of the vehicle without passing the radiator 6 into the engine room of the vehicle. 2 to 4 and 6 to 12, the second shutter 13 is disposed in the ventilation portion on the upper side of the fan shroud 8, but the position of the second shutter 13 is not limited to the upper side. Although not limited in particular, it is provided in a ventilation portion that takes outside air into the engine room of the vehicle without passing through the radiator 6. In addition, when opening a hole in the radiator 6 or arranging the two cores to share the fan shroud 8, the second shutter 13 is provided in the hole or the gap. For example, in the case of a commercial vehicle truck or the like, there is a gap between the radiator 6 and a cab (cabin) that is a box under the driver's seat on the left and right sides, and the second shutter 13 is provided in this portion. be able to.

  The second shutter 13 is configured to rotate around a rotation axis, and this rotation is rotated using an electric motor such as a tapping motor, a linear motion mechanism such as a solenoid, a hydraulic cylinder, a pneumatic cylinder, or the like. Configure. By opening and closing the second shutter 13, ventilation of the engine room is promoted and the frequency of rotation of the cooling fan 7 is reduced.

  The shutter opening / closing control device 15a is incorporated in an engine control device 15 called an ECU that controls the operation of the engine 4. The detected temperature Tcm of the coolant of the engine 4, the open / close state of the thermostat 9 that adjusts the inflow of the coolant of the engine 4 to the engine 4, and the on / off signal for the electronically controlled fan clutch 7a that controls the rotation of the cooling fan 7 Is used to control opening and closing of the first shutter 12 and the second shutter 13.

  In the present invention, the opening / closing control of the first shutter 12 and the second shutter 13 is performed as follows. In this open / close control, as shown in FIG. 5, the horizontal axis represents the engine load, and the vertical axis represents the coolant temperature, indicating the relationship between the load and the coolant temperature.

  Here, regarding the vertical axis, the temperature of the coolant at the start of operation of the engine 4 is T1, and the temperature of the coolant when it is considered that the warm-up operation of the engine 4 has been completed is T2. The temperature of the cooling water (valve opening start temperature) when the thermostat 9 opens the cooling water passage to the radiator 6 and starts to flow the cooling liquid to the radiator 6 is defined as T3. Further, the temperature of the cooling water (driving start temperature) when the electronic control fan clutch 7a is turned on and the cooling fan 7 starts to be driven is defined as T4. Using these temperatures T1, T2, T3, and T4, the temperatures T1 to T2 are the first temperature region Rt1, the temperatures T2 to T3 are the second temperature region Rt2, the temperatures T3 to T4 are the third temperature region Rt3, and the temperature T4 or higher. Is a fourth temperature region Rt4. Note that the temperature Tcm of the coolant and the temperatures T3 and T4 related to the control are the set temperature of the thermostat 9 and the temperature at which the fan starts rotating, and therefore vary depending on the type of the vehicle and the engine.

  When the relationship between the coolant temperature and the load is shown, in the first load region Rq1 after the engine 4 is started and the warm-up is completed and the low load operation is continued, the coolant temperature Tcm is It remains at temperature T3. Further, when the load increases and enters the second load region Rq2, the temperature Tcm of the coolant starts to increase. When the load further increases and enters the third load region Rq3, the temperature Tcm of the coolant becomes the temperature T3, and the thermostat 9 starts supplying the coolant to the radiator 6, so that it is cooled by the traveling wind and the coolant The temperature Tcm is stable and remains at the temperature T3.

  Furthermore, even if the load rises and enters the fourth load region Rq4 and the coolant temperature Tcm enters the fourth temperature region Rt3, the coolant of the radiator 6 is cooled only by natural ventilation of the traveling wind. Therefore, the temperature Tcm of the coolant rises. Further, when the load rises and enters the fifth load region Rq5, the temperature Tcm of the coolant rises and enters the fourth temperature region Rt4, the electronically controlled fan clutch 7a is turned on, and the cooling fan 7 Is driven and cooled by forced ventilation. Thereby, the temperature Tcm of the coolant is maintained in the vicinity of the temperature T4.

  As shown in the right side of FIG. 5, the first shutter 12 and the second shutter 13 are both closed in the first temperature range Rt1, as shown in the right side of FIG. In the second temperature region Rt2, both the first shutter 12 and the second shutter 13 are open. Further, in the third temperature region Rt3, the first shutter 12 is opened and the second shutter 13 is closed, and in the fourth temperature region Rt4, both the first shutter 12 and the second shutter 13 are closed. .

  By controlling the opening and closing of the first shutter 12 and the second shutter 13, the cooling fan 7 is stopped and the driving of the cooling fan 7 is stopped during the rise of the coolant temperature Tcm from the start of the engine 4 (first temperature region Rt 1). Both the first shutter 12 and the second shutter 13 are closed, and the first shutter 12 is closed to prevent natural cooling of the cooling air passing through the radiator 6 to avoid cooling of the coolant. Further, the second shutter 13 is closed to prevent ventilation by ventilation from the ventilation portion that does not pass through the radiator 6 into the engine room, thereby avoiding cooling of the engine disposed in the engine room. The engine warm-up performance is improved by suppressing both natural ventilation and ventilation.

  While the coolant temperature Tcm does not rise and is stable with exhaust loss (second temperature region Rt2), that is, after the engine 4 is warmed up, the coolant temperature Tcm rises and the thermostat 9 cools the radiator 6 Until the liquid passage is opened, the driving of the cooling fan 7 is stopped, the first shutter 12 is opened to generate natural ventilation of the cooling air passing through the radiator 6, and the second shutter 13 is also opened. Ventilation in the engine room is also performed by generating ventilation into the engine room from a ventilation part that does not pass through the radiator 6. The engine 4 is cooled by both natural ventilation and ventilation, and the drive energy of the cooling fan 7 is saved, and an increase in the coolant temperature Tcm is suppressed.

  When the coolant temperature Tcm further increases and the coolant is cooled by the radiator 6 (third temperature region Rt3), the driving of the cooling fan 7 is stopped and the first shutter 12 is opened. The natural ventilation of the cooling air passing through the radiator 6 is generated and the second shutter 13 is closed to increase the differential pressure before and after the radiator 6 to increase the amount of natural ventilation passing through the radiator 8. Thus, the increase in the temperature Tcm of the coolant is suppressed while saving the driving energy of the cooling fan 7.

  Further, when the temperature Tcm of the coolant further rises and there is a strong demand for cooling the coolant by the radiator 6 (fourth temperature region Rt4), the cooling fan 7 is driven and the first shutter 12 and The second shutter 13 is closed, the passage of outside air is concentrated on the cooling fan 7 to perform forced ventilation, and an increase in the coolant temperature Tcm is suppressed by a large amount of cooling air passing through the radiator 6. Thereby, overheating of the engine 4 is prevented.

  Next, the movement of the first shutter 12 and its operational effects, and the movement of the second shutter 13 and its operational effects will be described.

  The first shutter 12 is a structure for opening and closing a passage provided in the fan shroud 8 that covers the radiator 6 from the rear and guides the cooling air to the cooling fan 7. Is necessary, the cooling fan 7 is stopped using the cooling liquid temperature control of the prior art, and the first shutter 12 is closed to avoid cooling the cooling liquid.

  Further, when the temperature Tcm of the coolant becomes high and reaches a preset temperature T2, the first shutter 12 is opened and the coolant 6 is supplied to the radiator 6 by the thermostat 9 and passes through the radiator 6. The natural air passing through the radiator 6 to which the coolant is supplied is accelerated when the engine is cooled and the temperature of the coolant Tcm becomes high, and when the temperature reaches a preset temperature (valve opening start temperature) T3. Improves ventilation and cools the coolant. That is, when the temperature Tcm of the coolant is equal to or lower than a preset temperature (drive start temperature) T4, the first shutter 12 is opened without driving the cooling fan 7 and natural ventilation passing through the radiator 6 is promoted. To cool the coolant.

  When the coolant temperature Tcm becomes higher than a preset temperature (driving start temperature) T4, the first shutter 12 is closed while the cooling fan 7 is driven, and cooling by the cooling fan 7 is performed. Cooling of cooling liquid is promoted by sucking wind.

  The second shutter 13 is an opening / closing structure of a passage provided in the ventilation portion 11 that is a passage for the outside air that does not pass through the radiator 6. The second shutter 13 is used when the engine needs to be warmed up such as when the engine is started. Using the temperature control of the coolant of the prior art, the second shutter 13 is closed to stop the ventilation in the engine room to avoid the cooling of the engine 4 and improve the warm-up performance.

  When the temperature Tcm of the coolant increases and reaches a preset temperature T2, the second shutter 13 is opened and the coolant is supplied to the radiator 6 by the thermostat 9 until the coolant is supplied to the engine room. Increase ventilation and cool the engine.

  When the temperature Tcm of the coolant rises and reaches a preset temperature (valve opening start temperature) T3, the second shutter 13 is closed to stop the ventilation of the engine room and the coolant is supplied to the outside air for ventilation. The cooling of the coolant is promoted by passing through the radiator 6. This cooling of the cooling liquid is promoted when the cooling liquid temperature Tcm is equal to or lower than a preset temperature (driving start temperature) T4, since the cooling fan 7 is not driven, so natural ventilation is promoted and the driving temperature T4 is increased. When the temperature becomes higher, since the cooling fan 7 is driven, forced ventilation by the cooling fan 7 is promoted.

  The control from closing to opening of the first shutter 12 and the second shutter 13 is performed based on whether or not the temperature Tcm of the coolant has reached a preset temperature T2. Since the control from opening to closing of the first shutter 12 in the region where the temperature Tcm of the coolant is high is the same as the driving of the cooling fan 7 from OFF to ON, the ON / OFF signal of the electronically controlled fan clutch 7a or The control can be simplified by using an on / off signal for driving the electric cooling fan. On the other hand, the control from opening to closing of the second shutter 13 in the region where the coolant temperature Tcm is high is the same as the closing and opening of the coolant passage to the radiator 6 of the thermostat 9. And can simplify control.

  Next, a cooling system and cooling method for an internal combustion engine according to a second embodiment will be described. In the second embodiment, the structure of the first shutter 12 provided in the fan shroud 8 is different from the structure of the first shutter 12 of the first embodiment. This is the same as the embodiment.

  The fan shroud 8 of the second embodiment is a type in which the back surface of FIG. 6 is flat, and a first shutter 12 is provided as shown in FIGS. As shown in FIGS. 9 to 12, the opening and closing mechanism of the first shutter 12 and the second shutter 13 includes a cam 16b provided on a rotating shaft that is rotationally driven by a stepping motor 16a, and the first shutter 12. And a link mechanism provided in each of the second shutters 13.

  In this configuration, the first shutter 12 and the second shutter 13 are both closed as shown in FIG. 10 according to the rotational position of the cam 16b. Also, as shown in FIG. The two shutters 13 are opened together, and as shown in FIG. 12, the first shutter 12 is opened and the second shutter 13 is closed.

  In the case of the first temperature region Rt1 in FIG. 5 by controlling the first shutter 12 and the second shutter 13 and as in the first embodiment, as shown in FIGS. Both shutters 12 and 13 are closed, and in the case of the second temperature region Rt2 in FIG. 5, both shutters 12 and 13 are opened as shown in FIGS. Further, in the case of the third temperature region Rt3 in FIG. 5, as shown in FIGS. 17 and 18, the first shutter 12 is opened and the second shutter 13 is closed, and the fourth temperature in FIG. In the case of the region Rt4, as shown in FIGS. 19 and 20, both the shutters 12 and 13 are closed. Thereby, the same effect as the first embodiment can be obtained.

  According to the cooling system 1 and the cooling method of the internal combustion engine of the first and second embodiments described above, when the cooling fan 7 is stopped, the traveling air can be easily taken in and Heat damage can be prevented by suppressing the temperature. Thereby, the frequency which rotates the cooling fan 7 can be reduced and the energy consumed for driving the cooling fan 7 can be saved.

  Further, the opening and closing of the first shutter 12 and the second shutter 13 is performed using the coolant temperature Tcm, the opening / closing state of the passage of the coolant to the radiator 6, and the on / off signal for driving the cooling fan 7. Therefore, the opening / closing control corresponding to the situation of the vehicle and the engine 4 can be performed with relatively simple control.

It is a figure showing composition of an engine cooling system of a 1st embodiment concerning the present invention. It is a perspective view which shows the structure of the 1st shutter of 1st Embodiment. FIG. 3 is a side view showing a state where the first shutter of FIG. 2 is closed. FIG. 3 is a side view showing a state where the first shutter of FIG. 2 is opened. It is a figure which shows the temperature of a cooling fluid, the load of an engine, and the open / close state of a 1st shutter and a 2nd shutter. It is a perspective view which shows the fan shroud without a 1st shutter. It is a perspective view which shows the closed state of the 1st shutter in the engine cooling system of 2nd Embodiment. FIG. 8 is a perspective view showing a state where the first shutter of FIG. 7 is opened. It is a rear view of the fan shroud which shows the opening-and-closing structure of the 1st shutter of FIG. 7, and a 2nd shutter. FIG. 8 is a side view of the fan shroud showing a state where both the first shutter and the second shutter in FIG. 7 are closed. FIG. 8 is a side view of the fan shroud showing a state where both the first shutter and the second shutter in FIG. 7 are opened. FIG. 8 is a side view of the fan shroud showing a state in which the first shutter of FIG. 7 is opened and the second shutter is closed. FIG. 6 is a side view showing a state where both the first shutter and the second shutter of the second embodiment are closed in the first temperature region of FIG. 5. FIG. 6 is a front view showing a state where both the first shutter and the second shutter of the second embodiment are closed in the first temperature region of FIG. 5. FIG. 6 is a side view showing a state where both the first shutter and the second shutter of the second embodiment are opened in the second temperature region of FIG. 5. FIG. 6 is a front view showing a state where both the first shutter and the second shutter of the second embodiment are opened in the second temperature region of FIG. 5. FIG. 6 is a side view showing a state in which the first shutter of the second embodiment is opened and the second shutter is closed in the third temperature region of FIG. 5. FIG. 6 is a front view showing a state in which the first shutter according to the second embodiment is opened and the second shutter is closed in the third temperature region of FIG. 5. FIG. 6 is a side view showing a state where both the first shutter and the second shutter of the second embodiment are closed in the fourth temperature region of FIG. 5. FIG. 6 is a front view showing a state where both the first shutter and the second shutter of the second embodiment are closed in a fourth temperature region of FIG. 5.

Explanation of symbols

1 Engine Cooling System 2 Vehicle 3 Opening 4 Engine 5 Air Conditioning Condenser (Heat Exchanger)
6 Radiator (heat exchanger)
6a Radiator hose 7 Cooling fan 7a Electronically controlled fan clutch 8 Fan shroud 9 Thermostat (temperature adjusting means)
DESCRIPTION OF SYMBOLS 10 Water pump 11 Ventilation part 12 1st shutter 13 2nd shutter 14 Heater core (heat exchanger)
15 Engine control device 15a Shutter opening / closing control device (shutter opening / closing control means)
16a Stepping motor 16b Cam Rq1 First load region Rq2 Second load region Rq3 Third load region Rq4 Fourth load region Rq5 Fifth temperature region Rt1 First temperature region Rt2 Second temperature region Rt3 Third temperature region Rt4 Fourth temperature region T1, T2, T3, T4 Cooling water control temperature Tcm Coolant detection temperature

Claims (6)

A heat exchanger that cools a coolant of an internal combustion engine mounted in a vehicle by heat exchange with outside air, a ventilation portion that takes outside air into the engine room of the vehicle without passing through the heat exchanger, and a rear portion of the heat exchanger And a fan shroud that guides outside air to the cooling fan, and a cooling fan using an electronically controlled fan clutch or electric cooling that sucks in the outside air that is surrounded by the fan shroud and passes through the heat exchanger In an internal combustion engine cooling system comprising a fan and a fan rotation control device that controls transmission of rotation of the internal combustion engine to the cooling fan,
A first shutter that can be opened and closed at the fan shroud portion and a second shutter that can be opened and closed at the ventilation portion are provided, and the opening and closing control of the first shutter and the second shutter is further performed. A shutter opening / closing control means is provided, and
The shutter opening / closing control means includes: a temperature of the cooling liquid; an opening / closing state of the passage to the heat exchanger by a temperature adjusting means for opening / closing the passage of the cooling liquid to the heat exchanger; An internal combustion engine cooling system configured to perform opening / closing control of the first shutter and the second shutter using an on / off signal or an on / off signal for driving an electric cooling fan.   In the warm-up operation and the low-load operation of the internal combustion engine, the electronically controlled fan clutch or the electric cooling fan is turned off to stop the driving of the cooling fan, and the shutter opening / closing control means is configured to use the first shutter. 2. The cooling system for an internal combustion engine according to claim 1, wherein the second shutter is controlled to be closed.   While the cooling fluid passage to the heat exchanger is closed by the temperature adjusting means, the driving of the electronically controlled fan clutch or the electric cooling fan is turned off to stop the driving of the cooling fan, and the shutter 3. The cooling system for an internal combustion engine according to claim 1, wherein the opening / closing control means is configured to control to open the first shutter and the second shutter.   Although the coolant passage to the heat exchanger is opened by the temperature adjusting means, when the coolant temperature is lower than the preset temperature, the electronically controlled fan clutch or the electric cooling fan is turned off. The driving of the cooling fan is stopped, and the shutter opening / closing control means is controlled to open the first shutter and close the second shutter. The cooling system for an internal combustion engine according to 2 or 3.   If the coolant passage to the heat exchanger is opened by the temperature adjusting means and the temperature of the coolant is higher than a preset temperature, the electronically controlled fan clutch or the electric cooling fan is driven. And the shutter opening / closing control means controls to close the first shutter and the second shutter, while driving the cooling fan. A cooling system for an internal combustion engine according to any one of claims 3 and 4. A heat exchanger that cools a coolant of an internal combustion engine mounted in a vehicle by heat exchange with outside air, a ventilation portion that takes outside air into the engine room of the vehicle without passing through the heat exchanger, and a rear portion of the heat exchanger And a fan shroud that guides outside air to the cooling fan, and a cooling fan using an electronically controlled fan clutch or electric cooling that sucks in the outside air that is surrounded by the fan shroud and passes through the heat exchanger In a cooling method of an internal combustion engine comprising a fan and a fan rotation control device that controls transmission of rotation of the internal combustion engine to the cooling fan,
A first shutter that can be opened and closed at the fan shroud portion and a second shutter that can be opened and closed at the ventilation portion are provided, and the opening and closing control of the first shutter and the second shutter is further performed. A shutter opening / closing control means is provided, and
The shutter opening / closing control means includes: a temperature of the cooling liquid; an opening / closing state of the passage to the heat exchanger by a temperature adjusting means for opening / closing the passage of the cooling liquid to the heat exchanger; A cooling method for an internal combustion engine, wherein opening and closing control of the first shutter and the second shutter is performed using an on / off signal or an on / off signal for driving an electric cooling fan.

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