JP2020070766A - Engine cooling device - Google Patents

Abstract

To suppress an increase in water pressure at high speed of an engine.SOLUTION: An engine cooling device includes: a mechanical water pump 12; a radiator 19 in which a water pressure holding mechanism 25 is installed in a downstream side tank 23; and a cooling water control valve 15 that can vary an opening ratio of a radiator port P1 discharging cooling water to a radiator water passage 16. The engine cooling device further includes a control circuit 28 that controls the cooling water control valve 15 so that a request opening ratio in response to a cooling request from an engine 10 is set as the opening ratio of the radiator port P1 when engine speed is smaller than a predetermined high speed determination value and so that an opening ratio smaller than the request opening ratio is set as the opening ratio of the radiator port when the engine speed is the high speed determination value or greater.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an engine cooling device.

  Many automobile engines are provided with a water cooling type cooling device that cools the engine by circulating cooling water through the inside of the engine and a radiator. In such an engine cooling device, a radiator is installed in a water passage (hereinafter referred to as a radiator water passage) that guides cooling water after passing through the engine to a water pump. The radiator includes a pair of tanks and a plurality of tubes connecting the two tanks.

  On the other hand, as seen in Patent Document 1, as a radiator of a hermetic engine cooling device in which cooling water is hermetically sealed in a pressurized state, one of two tanks is provided for keeping a constant water pressure. Some have a radiator cap with a water pressure retention mechanism.

  As the radiator with a water pressure holding mechanism as described above, one of the two tanks, in which the water pressure holding mechanism is provided in the tank (upstream side tank) located on the upstream side in the cooling water flow direction, and the cooling water flow There is a tank provided on the downstream side in the direction (downstream side tank) provided with a water pressure holding mechanism. In a down-flow type radiator in which two tanks are arranged above and below to allow cooling water to flow from the upper tank to the lower tank, water pressure is maintained in the upper tank, that is, the upstream tank, to facilitate access to the radiator cap. In many cases, a mechanism is provided. On the other hand, most of the cross-flow type radiators in which the cooling water flows in the horizontal direction have a structure in which a water pressure holding mechanism is provided in the downstream side tank.

JP, 2001-073769, A

  Some engine cooling devices include a mechanical water pump that operates in response to rotation of the engine as a water pump that sends the cooling water that has passed through the radiator toward the inside of the engine. The flow rate of the cooling water discharged by the mechanical water pump increases as the engine speed increases. Therefore, in an engine cooling device that employs a mechanical water pump, the flow rate of cooling water that passes through the radiator (hereinafter, referred to as radiator flow rate) increases as the engine speed increases. Then, as the radiator flow rate increases, the water flow resistance of the radiator increases.

  When the upstream side tank is provided with the water pressure holding mechanism, the water pressure of the portion of the radiator water channel upstream of the radiator is held by the water pressure holding mechanism even if the water passage resistance of the radiator becomes high. On the other hand, when a water pressure holding mechanism is provided in the downstream tank, a radiator tube with large water resistance is interposed between the water pressure holding mechanism and a portion of the radiator waterway upstream of the radiator. ing. Therefore, in such a case, when the radiator flow rate increases and the water passage resistance of the radiator becomes higher, the water pressure at the upstream side of the radiator in the radiator water channel becomes higher accordingly. Therefore, in an engine cooling device that employs a radiator in which a water pressure holding mechanism is provided in a downstream tank and a mechanical water pump, the water pressure in a portion of the radiator water channel upstream of the radiator becomes high when the engine rotates at high speed. Therefore, it is necessary to use expensive parts with high pressure resistance as parts such as hoses and connectors that constitute the upstream side of the radiator in the radiator waterway, which is a factor that increases the manufacturing cost of the engine device. There is.

  Incidentally, in recent years, in order to achieve both the miniaturization of the radiator and the improvement of the cooling capacity, a large-capacity mechanical water pump is often used in the engine cooling device. On the other hand, the larger the capacity of the mechanical water pump, the larger the radiator flow rate at high engine speed. Therefore, the above problem is likely to occur in an engine cooling device that employs a large capacity mechanical water pump.

  The engine cooling device for solving the above-mentioned problems is a radiator including a pair of tanks connected via a plurality of tubes, and a downstream side tank which is a tank located on the downstream side in the cooling water flow direction of the pair of tanks. A water pressure holding mechanism that is installed and holds the water pressure of the downstream side tank at a constant pressure, and a mechanical water pump that operates by receiving the rotation of the engine and sends the cooling water toward the inside of the engine are provided. At the same time, the water passage that guides the cooling water that has passed through the engine to the water pump is branched into a radiator water passage that passes through the radiator and a bypass water passage that bypasses the radiator, and a radiator port that leads the cooling water to the radiator water passage. It has a cooling water control valve that can change the opening ratio of the. Further, the engine cooling device calculates the required value of the opening ratio of the radiator port according to the cooling request of the engine, and when the engine speed is equal to or lower than the predetermined high rotation determination value, the opening ratio of the radiator port is set to A control circuit is provided that controls the cooling water control valve so that the opening ratio is the same as the required value and the opening ratio of the radiator port is smaller than the required value when the engine speed exceeds the high speed judgment value. There is.

  In the radiator water channel in such an engine cooling device, the tube portion of the radiator has the highest water resistance. The water flow resistance in such a tube increases as the flow rate of cooling water (radiator flow rate) flowing through the radiator water channel increases. When a water pressure retention mechanism is installed in the downstream tank located downstream of the tube in the radiator, if the water resistance of the tube increases, the water pressure in the upstream part of the radiator waterway higher than that of the radiator will increase. .. On the other hand, in the mechanical water pump, the discharge flow rate of the cooling water increases as the engine speed increases. Therefore, when the opening ratio of the radiator port of the cooling water control valve is large when the engine is running at high speed, the radiator flow rate increases and the water flow resistance of the tube increases, so the upstream of the radiator in the radiator waterway is higher than the radiator. There is a risk that the water pressure in the side portion will become too high.

  On the other hand, when the engine speed exceeds the high speed determination value, the control circuit of the engine cooling device controls the opening rate of the radiator port to be smaller than the opening rate set according to the cooling request of the engine. The cooling water control valve is controlled as follows. Therefore, at high engine speed, the radiator flow rate is limited, and the increase in water resistance of the tube due to the increase in the radiator flow rate is suppressed. Therefore, according to the engine cooling device described above, it is possible to suppress an increase in water pressure in a portion of the radiator water passage upstream of the radiator when the engine rotates at high speed.

The schematic diagram which shows the structure of one Embodiment of an engine cooling device. The graph which shows the relationship between the valve phase in the cooling water control valve provided in the same engine cooling device, and the opening ratio of each port. The flowchart of the radiator flow volume control routine which the control circuit provided in the same engine cooling device performs. The graph which shows the relationship between the limit rate C calculated in the same radiator flow control routine, and the engine speed NE. 6 is a graph showing the relationship between the target opening ratio and the hose pressure and the engine speed when the engine speed is changed while the required opening ratio is fixed at 100% in the engine cooling device.

Hereinafter, an embodiment of the engine cooling device will be described in detail with reference to FIGS. 1 to 5. Here, first, the configuration of the engine cooling device of the present embodiment will be described with reference to FIG.
As shown in FIG. 1, a water jacket 11 through which cooling water flows is provided inside the engine 10. A mechanical water pump 12 that discharges the cooling water toward the water jacket 11 is attached to a portion of the engine 10 that serves as an inlet for the cooling water to the water jacket 11. The water pump 12 is drivingly connected to the crankshaft 14 of the engine 10 through the winding transmission mechanism 13, and operates by receiving the rotation of the engine 10.

  On the other hand, a cooling water control valve 15 is attached to a portion of the engine 10 which serves as an outlet for cooling water from the water jacket 11. In the engine cooling device of the present embodiment, the water passage that guides the cooling water that has passed through the inside of the engine 10 (water jacket 11) to the water pump 12 is branched into three water passages of the radiator water passage 16, the device water passage 17, and the heater water passage 18. Has been done. The cooling water control valve 15 has three radiator ports P1 for drawing cooling water to the radiator water channel 16, a device port P2 for drawing cooling water to the device water channel 17, and a heater port P3 for drawing cooling water to the heater water channel 18. A discharge port is provided.

  The radiator water passage 16 is provided with a radiator 19 that cools the cooling water that has become hot due to the heat of the engine 10 in the water jacket 11. On the other hand, the device water passage 17 is provided with various devices 20 that utilize the heat of the cooling water, and the heater water passage 18 is provided with a heater core 21 for heating the passenger compartment. The device 20 may be an EGR cooler that cools EGR gas, an ATF warmer, or the like. The ATF warmer is a heat exchanger that exchanges heat between the cooling water and the oil of the automatic transmission (hereinafter referred to as AT oil). Such an ATF warmer gives heat of cooling water to the AT oil to accelerate the warming of the automatic transmission when the AT oil is at a low temperature, while it heats the AT oil when the AT oil becomes too hot. It takes the role of cooling the AT oil by removing the cooling water. In the engine cooling device of the embodiment, the two water channels, the device water channel 17 and the heater water channel 18, form a bypass water channel that bypasses the radiator 19.

  In the engine cooling device of the present embodiment, as the radiator 19, a cross-flow type radiator in which the flow direction of the cooling water inside is horizontal is adopted. The radiator 19 includes a pair of tanks (22, 23) respectively provided at positions separated in the horizontal direction, and a plurality of tubes 24 that connect the tanks and extend in the horizontal direction. In the following description, of the two tanks provided in the radiator 19, the tank located upstream in the cooling water flow direction is the upstream tank 22 and the tank located downstream in the cooling water flow direction. Is described as the downstream side tank 23, respectively.

  A radiator cap 26 with a water pressure holding mechanism 25 is attached to the downstream tank 23. The downstream tank 23 is connected to a reserve tank 27, which is a container for storing cooling water, via a water pressure holding mechanism 25. The water pressure holding mechanism 25 is composed of two valves, a pressurizing valve and a negative pressure valve. Of these, the pressurizing valve opens when the water pressure in the downstream tank 23 becomes too high, and allows the movement of the cooling water from the downstream tank 23 to the reserve tank 27. On the other hand, the negative pressure valve opens when the water pressure in the downstream tank 23 becomes too low, and allows the movement of the cooling water from the reserve tank 27 to the downstream tank 23. The water pressure holding mechanism 25 holds the water pressure of the downstream side tank 23 within a proper range by the functions of the pressurizing valve and the negative pressure valve.

  By the way, a portion of the radiator water channel 16 upstream of the radiator 19 is a radiator hose, a radiator port P1 of the cooling water control valve 15, and a connector for connecting the hose to the upstream tank 22 of the radiator 19, respectively. It is composed by. In the engine cooling device of the present embodiment, as such a connector, instead of the quick connector adopted in many engine cooling devices, a cheaper single clamp or double clamp is used, although the pressure resistance is lower than that of the quick connector. ing.

  Further, the engine cooling device of the present embodiment is provided with a control circuit 28 that controls the cooling water control valve 15. Detection signals such as the cooling water temperature TW, the oil temperature TF, and the engine speed NE are input to the control circuit 28. The cooling water temperature TW here represents the temperature of the cooling water when it flows out from the water jacket 11, and the oil temperature TF represents the temperature of the AT oil.

  Next, details of the cooling water control valve 15 will be described. Inside the cooling water control valve 15, a rotatably provided valve element and a motor for rotating the valve element are incorporated. The opening areas of the radiator port P1, the device port P2, and the heater port P3 in the cooling water control valve 15 change according to the rotation of the valve body by the motor.

  In the present embodiment, as the motor for the cooling water control valve 15, a DC motor with a brush is used in which the rotation direction is reversed by reversing the energization direction. In the following description, the rotation direction of the valve body when the energization direction of the motor is the predetermined direction is the positive direction, and the rotation direction of the valve body when the energization direction is the opposite direction is the negative direction. ..

  FIG. 2 shows the relationship between the valve phase φ of the valve body of the cooling water control valve 15 and the opening ratio of each discharge port. In addition, the valve phase φ represents a rotation angle of the valve body in the plus direction and the minus direction from the position where the valve phase φ is 0 ° at a position where all the three discharge ports are closed. ing. Further, the opening ratio represents the ratio of the opening area of each discharge port, with the opening area at full opening being 100%.

  As shown in the figure, the opening ratio of each discharge port is set so as to change depending on the valve phase φ of the valve body. Note that the range of the valve phase φ in the positive direction from the position where the valve phase φ is 0 ° is the range of the valve phase φ used when heating the passenger compartment (winter mode use range). The range of the valve phase φ in the minus direction from the position of 0 ° is the range of the valve phase φ used when the vehicle interior is not heated (summer mode use range).

  When the valve body is rotated in the plus direction from the position where the valve phase φ is 0 °, the heater port P3 first starts to open, and the opening ratio of the heater port P3 gradually increases as the valve phase φ increases in the plus direction. When the heater port P3 is fully opened, that is, when the opening ratio reaches 100%, the device port P2 starts to open next, and the opening ratio of the device port P2 gradually increases as the valve phase φ increases in the positive direction. Then, when the device port P2 is fully opened, that is, when the aperture ratio reaches 100%, the radiator port P1 starts to open. After that, as the valve phase φ further increases in the plus direction, the opening ratio of the radiator port P1 gradually increases, and eventually reaches 100%.

  On the other hand, when the valve body is rotated in the minus direction from the position where the valve phase φ is 0 °, the device port P2 first starts to open, and the opening ratio of the device port P2 gradually increases as the valve phase φ increases in the minus direction. Become. Then, when the device port P2 is fully opened, that is, when the aperture ratio reaches 100%, the radiator port P1 starts to open. As the valve phase φ further increases in the negative direction thereafter, the opening ratio of the radiator port P1 gradually increases and eventually reaches 100%. Incidentally, the heater port P3 is always fully closed in the summer mode use range in the minus direction of the position where the valve phase φ is 0 °.

  When the warm-up of the engine 10 is completed, control of the cooling water flow rate (hereinafter, referred to as radiator flow rate) of the radiator water channel 16 by the control circuit 28 is started. The radiator flow rate control is performed by adjusting the opening ratio of the radiator port P1 according to the deviation of the cooling water temperature TW from the target water temperature set according to the operating condition of the engine 10.

  FIG. 3 shows a flowchart of a radiator control routine executed by the control circuit 28 for controlling the radiator flow rate. After the engine 10 has been warmed up, the control circuit 28 repeatedly executes the processing of this routine every predetermined control cycle.

  When the processing of this routine is started, first, in step S100, a required opening ratio θr, which is a required value of the opening ratio θ of the radiator port P1, is calculated. The calculation of the required opening ratio θr in the present embodiment is performed by updating the value of the required opening ratio θr according to the deviation of the cooling water temperature TW from the target temperature. Specifically, when the current cooling water temperature TW is higher than the target water temperature and the cooling capacity of the engine 10 is insufficient, the required opening so that the updated value becomes larger than the value before updating. The value of the rate θr is updated. On the other hand, when the current cooling water temperature TW is lower than the target water temperature and the cooling capacity of the engine 10 is excessive, it is requested that the value after update be smaller than the value before update. The value of the aperture ratio θr is updated. In this way, the required opening ratio θr is calculated as the required value of the opening ratio of the radiator port P1 set according to the cooling request of the engine 10.

  Succeedingly, in a step S110, it is determined whether or not the cooling water temperature TW is less than a predetermined high water temperature determination value. If the cooling water temperature TW is less than the high water temperature determination value (YES), the process proceeds to step S120, and if the cooling water temperature TW is the high water temperature determination value or more (NO), the process proceeds to step S170. The upper limit value of the allowable cooling water temperature TW is set as the high water temperature determination value. That is, when the cooling water temperature TW is equal to or higher than the high water temperature determination value, the cooling water temperature TW is too high, and the lowering of the cooling water temperature TW for cooling the engine 10 should be prioritized over other requests. ing.

  When the process proceeds to step S170, the value of the required opening ratio θr is set as it is as the value of the target opening ratio θt in step S170. Then, in step S160, the motor of the cooling water control valve 15 is controlled so as to change the valve phase φ of the cooling water control valve 15 to a valve phase in which the opening ratio of the radiator port P1 becomes the target opening ratio θt. After that, the processing of this routine this time is ended. That is, when the process proceeds to step S170, the control circuit 28 determines that the opening ratio θ of the radiator port P1 is the required value (required opening ratio θr) of the opening ratio θ set according to the cooling request of the engine 10. The cooling water control valve 15 is controlled so that the opening ratio is the same.

  On the other hand, when the process proceeds to step S120, it is determined in step S120 whether the oil temperature TF of the automatic transmission is lower than the predetermined high oil temperature determination value. If the oil temperature TF is lower than the high oil temperature determination value (YES), the process proceeds to step S130, and if the oil temperature TF is higher than the high oil temperature determination value (NO), the process proceeds to step S170. The upper limit of the allowable oil temperature TF range is set as the high oil temperature determination value. That is, when the oil temperature TF is equal to or higher than the high oil temperature determination value, the oil temperature TF is too high, and lowering of the cooling water temperature TW for cooling the oil and the engine 10 should be prioritized over other requests. The situation is. Even in such a case, the control circuit 28 controls the cooling water control valve 15 so that the opening ratio of the radiator port P1 becomes the same opening ratio as the required opening ratio θr.

  If the oil temperature TF is less than the high oil temperature determination value and the process proceeds to step S130, whether or not the current engine speed NE is equal to or higher than the predetermined high rotation determination value α in step S130. To be judged. If the engine speed NE is equal to or higher than the high speed determination value α (YES), the process proceeds to step S140, and if the engine speed NE is lower than the high speed determination value α (NO), the process proceeds to step S170. Be done. When the process proceeds to step S170 as described above, the control circuit 28 controls the cooling water control valve 15 so that the opening rate of the radiator port P1 becomes the same opening rate as the required opening rate θr.

  On the other hand, when the engine speed NE is equal to or higher than the high speed determination value α and the process proceeds to step S140, the value of the limiting ratio C is calculated in step S140. The value of the limiting rate C is set to a value in the range of 0 or more and 1 or less according to the engine speed NE.

  FIG. 4 shows how the limiting rate C is set. As shown in the figure, when the engine speed NE is the high speed determination value α, 1 is set as the value of the restriction ratio C. Further, when the engine speed NE is equal to or higher than the predetermined value β which is larger than the high speed determination value α, 0 is set as the value of the restriction ratio C. Then, when the engine speed NE exceeds the high speed determination value α and is less than the predetermined value β, the engine speed NE is preset from 1 which is the value when the engine speed NE is the high speed determination value α. The value of the restriction ratio C is set so that the value decreases with the increase of the engine speed NE up to 0 which is the value β. The default value β in the figure is a value larger than the maximum rotation speed MAX of the engine 10. Then, in the range from the high rotation speed determination value α to the maximum rotation speed MAX, the cooling water flowing out from the radiator port P1 when the value obtained by converting the restriction ratio C into a unit is set as the value of the opening ratio θ of the radiator port P1. The value of the limiting rate C is set so that the flow rate of is kept constant. It should be noted that the value of the limiting ratio C in the range equal to or higher than the maximum rotation speed MAX is a value that is set but is not actually used.

  When the limiting rate C is calculated, in the subsequent step S150, the product of the required opening rate θr and the value of the limiting rate C is set as the value of the target opening rate θt. Then, in step S160 described above, the motor of the cooling water control valve 15 is controlled so as to change the valve phase φ of the cooling water control valve 15 to a valve phase in which the opening ratio of the radiator port P1 becomes the target opening ratio θt. After this, the processing of this routine is terminated. As described above, the limit rate C when the engine speed NE exceeds the high rotation determination value α is set to a value of 0 or more and less than 1. Then, in this case, the product of the required opening ratio θr and the limiting ratio C is set as the value of the target opening ratio θt (S150). Therefore, in this case, that is, when the engine speed NE exceeds the high speed determination value (S130: YES), the control circuit 28 sets the aperture ratio θ of the radiator port P1 to a smaller aperture ratio than the required aperture ratio θr. Therefore, the cooling water control valve 15 is controlled.

The operation and effect of this embodiment will be described.
In the radiator water channel 16 in the engine cooling device as described above, the portion of the tube 24 of the radiator 19 formed of a thin tube has the highest water resistance. The water flow resistance of the tube 24 increases as the flow rate of the cooling water flowing through the tube 24, that is, the radiator flow rate increases. On the other hand, in the radiator 19 adopted by the engine cooling device of the present embodiment, the water pressure holding mechanism 25 that holds the water pressure is provided in the downstream side tank 23 located downstream of the tube 24 in the cooling water flow direction. Therefore, when the water passage resistance of the tube 24 increases, the water pressure of the portion of the radiator water passage 16 on the upstream side of the radiator 19 increases.

  FIG. 5 shows the target opening ratio θt and the hose pressure when the engine speed NE is changed while the required opening ratio θr of the radiator port P1 in the engine cooling device of the present embodiment is fixed at 100%, and the engine rotation speed. The relationship between the number NE and is shown. The hose pressure represents the pressure of the cooling water led from the radiator port P1 of the cooling water control valve 15 to the radiator water passage 16. In the figure, the relationship between the hose pressure and the engine speed NE when the target opening ratio θt is fixed to 100% as well as the required opening ratio θr as shown by the broken line is also shown by a chain double-dashed line. There is.

  As described above, the engine cooling device of the present embodiment employs the mechanical water pump 12 that operates by receiving the rotation of the engine 10. Therefore, the flow rate of the cooling water discharged by the water pump 12 (hereinafter referred to as the pump discharge amount) increases as the engine speed NE increases. When the aperture ratio θ of the radiator port P1 is kept constant, the radiator flow rate also increases as the pump discharge amount increases. Therefore, when the target opening ratio θt is fixed to 100%, the hose pressure increases as the engine speed NE increases, and eventually the hose pressure exceeds the normal limit pressure. Note that the normal working limit pressure here represents the upper limit value of the normal working range of the hose pressure determined by the pressure resistance performance of the radiator hose and the connector constituting the upstream side of the radiator 19 in the radiator water channel 16. By the way, in the present embodiment, when the engine speed NE is increased from 0 while the opening ratio θ of the radiator port P1 is set to 100%, the engine speed when the hose pressure rises to the normal limit pressure. NE is set as the value of the high rotation determination value α.

  On the other hand, in the engine cooling device of the present embodiment, when the cooling water temperature TW and the oil temperature TF are too high, or when the engine speed NE is the high speed determination value α or less, the cooling demand of the engine 10 is satisfied. The required aperture ratio θr set accordingly is directly set as the value of the target aperture ratio θt. On the other hand, when the cooling water temperature TW and the oil temperature TF are not too high and the engine speed NE exceeds the high rotation determination value α, the target opening ratio smaller than the required opening ratio θr is set. It is set as the value of θt. For example, as shown in FIG. 5, when the required opening ratio θr is 100%, the hose pressure is maintained at the normal limit pressure as the value of the target opening ratio θt in the region where the engine speed NE is the high rotation determination value α or more. Possible values are set. Therefore, it is possible to suppress the radiator flow rate so that the hose pressure does not become too high at the time of high rotation of the engine 10 in which the pump discharge amount increases. Even in the engine cooling device of the present embodiment, when the cooling water temperature TW and the oil temperature TF are too high, the value of the required opening ratio θr even if the engine speed NE exceeds the high speed determination value α. Is set as the value of the target opening ratio θt as it is, and the cooling of the cooling water or the AT oil is prioritized.

  In addition, when the hose pressure at the time of high rotation of the engine 10 cannot be sufficiently suppressed, as a component of a radiator hose or a connector that constitutes a portion of the radiator waterway 16 on the upstream side of the radiator 19, it has high pressure resistance and is expensive. It is necessary to adopt various parts. In this respect, in the engine cooling device of the present embodiment, since it is possible to adopt a cheaper component having a lower pressure resistance performance as such a component, the manufacturing cost of the engine cooling device can be suppressed.

  When a large radiator cannot be adopted due to restrictions such as installation space, the cooling performance of the engine cooling device may be secured by using a large capacity water pump. However, when the hose pressure at the time of high rotation of the engine 10 cannot be sufficiently suppressed, the employable water pump has suppressed the pump discharge amount at the time of high rotation to the range where the hose pressure becomes equal to or lower than the working limit pressure. It is limited to low-capacity ones. In this respect, in the engine cooling device of the present embodiment, the hose pressure during high rotation of the engine 10 can be suppressed by controlling the cooling water control valve 15, so that it is easy to adopt a large capacity water pump.

This embodiment can be modified and implemented as follows. The present embodiment and the following modified examples can be implemented in combination with each other within a technically consistent range.
In the above-described embodiment, the required opening ratio θr is calculated according to the cooling request of the engine 10 by updating the value according to the deviation of the cooling water temperature TW from the target water temperature. The same calculation may be performed.

  In the above-described embodiment, when the cooling water temperature TW is equal to or higher than the high water temperature determination value, or when the oil temperature TF is equal to or higher than the high oil temperature determination value, even when the engine speed NE exceeds the high rotation determination value α, the radiator is used. The cooling water control valve 15 is controlled so that the opening ratio of the port P1 becomes the required opening ratio θr. When the hose pressure becomes higher until the connector is detached when the opening rate of the radiator port P1 is kept at the required opening rate θr, in which case the suppression of the hose pressure should be prioritized over the reduction of the cooling water temperature TW and the oil temperature TF. There is. In such a case, regardless of the cooling water temperature TW and the oil temperature TF, when the engine speed NE exceeds the high speed determination value α, the aperture ratio of the radiator port P1 is always smaller than the required aperture ratio θr. The cooling water control valve 15 may be controlled as described above.

  10 ... Engine, 11 ... Water pump, 12 ... (Mechanical) water pump, 13 ... Winding transmission mechanism, 14 ... Crankshaft, 15 ... Cooling water control valve, 16 ... Radiator waterway, 17 ... Device waterway (bypass waterway) ), 18 ... Heater channel (bypass channel), 19 ... Radiator, 20 ... Device, 21 ... Heater core, 22 ... Upstream tank, 23 ... Downstream tank, 24 ... Tube, 25 ... Water pressure retention mechanism, 26 ... Radiator cap, 27 ... Reserve tank, 28 ... Control circuit, P1 ... Radiator port, P2 ... Device port, P3 ... Heater port.

Claims (1)

A radiator provided with a pair of tanks connected via a plurality of tubes, and a water pressure in the downstream tank installed in a downstream tank which is a tank located on the downstream side in the cooling water flow direction of the pair of tanks. And a mechanical water pump that operates by receiving the rotation of the engine to deliver cooling water toward the inside of the engine, and collects the cooling water that has passed through the inside of the engine. Cooling in which a water channel leading to the water pump is branched into a radiator water channel that passes through the radiator and a bypass water channel that bypasses the radiator, and the opening ratio of a radiator port that guides cooling water to the radiator water channel is variable. In an engine cooling device with a water control valve,
The required value of the opening ratio of the radiator port is calculated according to the cooling demand of the engine, and when the engine speed is equal to or lower than a predetermined high rotation determination value, the opening ratio of the radiator port is set to the same opening as the required value. And a control circuit for controlling the cooling water control valve so that the opening ratio of the radiator port is smaller than the required value when the engine speed exceeds the high rotation determination value. Engine cooling system.