JP2007170352A - Engine cooling device and electronically controlled flow control valve used for the device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronically controlled flow control valve in which the occurrence of thermal strain is reduced, and an engine cooling device. <P>SOLUTION: This engine cooling device comprises a radiator 1 cooling an engine 2 by circulating cooling water (LLC) for an engine 2, a radiator circuit formed between the radiator 1 and the engine 2, a water pump 4 forcibly circulating cooling water in the radiator circuit, an electric thermostat 3 serving as the electronically controlled flow control valve for controlling the flow of cooling water into the radiator 1, an electric fan 9 feeding cooling air to the radiator 1, a water temperature sensor 7 detecting the temperature of cooling water, and an ECU 6. When the ECU 6 recognizes the acceleration of a vehicle, it temporarily closes the electric thermostat 3, and after a predetermined time, gradually increases the opening of the electric thermostat 3 to control the flow of the cooling water. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an engine cooling device that circulates cooling water for cooling a vehicle engine between a radiator and an engine, and to an electronically controlled flow control valve used in the engine cooling device.

Conventionally, this type of electronically controlled flow control valve and engine cooling device includes an electronically controlled thermostat that arbitrarily variably controls the coolant temperature according to the state of the engine, and an element temperature sensing unit in the temperature sensing chamber. And a heat transfer means for directly or indirectly transmitting the cooling water temperature on the radiator outlet side, and the structure is eliminated by eliminating the need for a sensor or control unit for detecting the temperature on the radiator outlet side. What is simplified is known (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 2003-328753

  However, in the above-mentioned Patent Document 1, there can be a drift in which the cooling water does not flow uniformly in the radiator and the flow is uneven. When such a drift occurs, if the inflowing cooling water increases, the cooling water further flows into the drift portion, so that the temperature difference between the drift portion and the non-shift portion further expands and thermal distortion is promoted. There is a problem that.

  Accordingly, an object of the present invention is to provide an electronically controlled flow rate control valve and an engine cooling device that reduce the occurrence of thermal distortion.

  In order to achieve the above object, the following technical means are adopted. In other words, the first invention of the engine cooling device includes a radiator (1) connected to a water jacket of the engine (2), and a radiator circuit formed so as to communicate the radiator (1) and the engine (2) ( 12, 13, 14), a water pump (4) for forcibly circulating cooling water through the radiator circuit (12, 13, 14), and an electronically controlled flow rate for controlling the flow rate of cooling water to the radiator (1) And a control means (6) for controlling at least the electronically controlled flow control valve (3). Further, according to the present invention, when the control means (6) recognizes the acceleration of the vehicle, the electronic control type flow rate control valve (3) is once closed, and after a predetermined time has elapsed, the electronic control type flow rate control valve (3) is opened. The flow rate of the cooling water is controlled by gradually increasing the degree.

  According to the first aspect of the present invention, the cooling to the radiator at the vehicle speed is performed by performing the control for limiting the water flow rate to the radiator without operating the circulating flow rate of the cooling water in the engine in a situation where the engine is likely to be loaded. The drift can be reduced by the wind and the occurrence of thermal strain can be suppressed.

  Furthermore, it is preferable that the transition condition to the flow rate control of the cooling water in the first invention is when the outside air temperature falls below a predetermined value. According to this invention, the flow rate control of the cooling water in the first invention is executed when the outside air temperature is lower than a predetermined value, for example, extremely low temperature, so that the viscosity of the cooling water is reduced. It is possible to suppress the drift by detecting the situation in which the drift is likely to occur.

  Furthermore, it is preferable that the transition condition to the flow rate control of the cooling water in the first invention is when the rotational speed of the engine (2) falls below a predetermined value. According to this invention, when the engine speed falls below a predetermined value, the flow rate control of the cooling water in the first invention is executed, so that it is possible to detect a situation in which a drift is likely to occur due to a small amount of water flow to the radiator. Thus, drift can be suppressed.

  Furthermore, it is preferable that the transition condition to the flow rate control of the cooling water in the first invention is when the vehicle speed falls below a predetermined value. According to the present invention, when the vehicle speed falls below a predetermined value, the flow rate control of the cooling water in the first invention is executed to detect a situation in which a drift is likely to occur due to a small amount of ventilation to the radiator. The drift can be suppressed.

  Furthermore, the transition conditions to the flow rate control of the cooling water in the first invention are that the outside air temperature is below a predetermined value, the rotational speed of the engine (2) is below a predetermined value, and the vehicle speed is below a predetermined value, It is preferable that all the conditions are satisfied.

  The drift of the cooling water passed to the radiator has a low flow rate to the radiator and a wind speed passing through the radiator, and has a high probability of being generated at an extremely low temperature. The flow rate inside the engine, the radiator passing wind speed, and the outside air temperature can be estimated from the sensor signal input to the control means. Therefore, according to the present invention, it is possible to estimate each drift generation condition from the signal of each sensor and determine the occurrence of the drift. And since the frequency | count of a drive of an electronically controlled flow control valve can be reduced, the useable drive of a control valve can be excluded and a suitable lifetime can be ensured.

  The first invention of the electronically controlled flow control valve is an electronically controlled flow control valve for controlling the flow rate of cooling water of the engine (2) forcedly sent by the water pump (4) into the radiator (1). (3) It is characterized in that the flow rate of the cooling water is controlled by closing the valve once when the vehicle accelerates and gradually increasing the opening degree after a predetermined time has elapsed.

  According to the present invention, in a situation where the engine is likely to be loaded, by controlling the flow rate of water to the radiator without manipulating the circulating flow rate of the cooling water in the engine, the cooling air to the radiator is controlled by the vehicle speed. An electronically controlled flow control valve that reduces drift and suppresses the occurrence of thermal strain is obtained.

  The dependent claim in the first invention is the same as that of the first invention of the engine cooling device described above, and the function and effect thereof are also the same.

  In addition, the code | symbol in the bracket | parenthesis of each said means shows a corresponding relationship with the specific means of embodiment mentioned later.

(First embodiment)
A first embodiment of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is an explanatory diagram showing the configuration of the engine cooling device according to the present embodiment. FIG. 2 is a flowchart showing the flow rate control of the cooling water by the electric thermostat or the engine cooling device in the present embodiment.

  As shown in FIG. 1, the engine cooling device of the present embodiment includes a radiator 1 that cools the engine 2 by circulating cooling water (LLC) of the engine 2 that is a water-cooled internal combustion engine, and the radiator 1 and the engine 2. , A water pump 4 that forcibly circulates cooling water through the radiator circuit, and an electric thermostat 3 that is an electronically controlled flow control valve that controls the flow of the cooling water to the radiator 1 And an electric fan 9 for supplying cooling air to the radiator 1, a water temperature sensor 7 for detecting the temperature of the cooling water, and an engine control unit (hereinafter referred to as ECU) 6.

  Further, the ECU 6 transmits temperature information detected by the water temperature sensor 7 and various data detected by various sensors, and controls at least the electric thermostat 3 and the electric fan 9. The radiator circuit is connected to a heater 5 that heats the conditioned air using cooling water as a heating source of hot water.

  A water jacket formed inside the engine 2 is connected to a cooling water outlet 8 of the engine 2. The passage connected to the cooling water outlet 8 is branched into a heater inlet side passage 10 connected to the heater 5 and a radiator inlet side passage 12 connected to the radiator 1.

  A radiator outlet side passage 14 is connected to the outlet side of the radiator 1, and the radiator outlet side passage 14 is connected to a cooling water inlet of the engine 2 and communicates with a water jacket. An electric thermostat 3 and a water pump 4 are disposed in the middle of the radiator outlet side passage 14.

  The radiator inlet-side passage 12 branches to the bypass passage 13 before the radiator 1. The bypass passage 13 is connected to the radiator outlet side passage 14 at the junction 15. The junction 15 is located in the passage between the electric thermostat 3 and the water pump 4. A heater outlet side passage 11 is connected to the outlet side of the heater 5, and the heater outlet side passage 11 is connected to the merging portion 15 to join the bypass passage 13 and the radiator outlet side passage 14.

  A circuit formed in the order of the water jacket inside the engine 2, the heater outlet side passage 12, the radiator 1, the heater outlet side passage 14, and the water jacket is a basic coolant circulation path. In this cooling water circulation path, the cooling water heated to a high temperature by the water jacket is radiated by the cooling air from the electric fan 9 or the like by the radiator 1 and returns to the engine 2 again. In addition, the arrow shown in FIG. 1 represents the flow of cooling water.

  The radiator 1 cools the cooling water circulating through the radiator circuit by the water pump 4 by exchanging heat with the outside air. Further, in the bypass passage 13 provided in the radiator circuit, the cooling water bypassing the radiator 1 flows, and the amount of cooling water flowing through the radiator 1 and the amount of cooling water flowing through the bypass passage 13 are adjusted by the electric thermostat 3. It is like that.

  In particular, at the time of warming up, the amount of cooling water on the bypass passage 13 side is increased and warming up is promoted. That is, overcooling of the cooling water by the radiator 1 is prevented. Further, the pipe of the passage connected in the order of the engine 2, the radiator 1, the electric thermostat 3, and the water pump 4 in the radiator circuit has a larger pipe inner diameter than the pipes constituting other circuits, and a large amount of cooling water flows. It will be.

  The water pump 4 uses a mechanical pump. Since the mechanical pump has a characteristic that is synchronized with the engine speed, the flow rate is increased in proportion to the engine speed.

  On the other hand, the water pump 4 can also use an electric pump. When the water pump 4 is constituted by an electric pump, the ECU 6 variably controls the ON duty ratio of the drive signal pulse signal, so that the rotational speed, the pump discharge It is configured so that the amount can be controlled arbitrarily. Even if the water pump 4 is constituted by an electric pump, control for stopping the circulation of the cooling water or reducing the circulation amount is not performed when there is a load on the engine 2. This is because a certain amount or more of cooling water is circulated because it is necessary to keep the temperature difference between the inlet temperature and the outlet temperature of the cooling water in the engine 2 within a predetermined range.

  The electric thermostat 3 is configured such that the opening degree and flow rate can be arbitrarily controlled by the ECU 6 variably controlling the ON duty ratio of the drive signal pulse signal. When the opening degree of the electric thermostat 3 decreases, the flow rate of the cooling water flowing through the radiator 1 decreases and the flow rate flowing through the bypass passage 13 increases. Conversely, when the opening degree of the electric thermostat 3 increases, the flow rate of the cooling water flowing through the bypass passage 13 decreases and the flow rate flowing through the radiator 1 increases.

  Note that the electric thermostat 3 of the present embodiment is normally controlled by the ECU 6 so that the temperature of the cooling water approaches the set target value, but PID control is used as an example. The electric thermostat 3 serves to control the ratio between the flow rate of the cooling water flowing through the radiator 1 and the flow rate flowing through the bypass passage 13 that does not flow through the radiator 1, and its position is located on the outlet side of the radiator 1. For example, it may be disposed on the inlet side of the radiator 1.

  The electric fan 9 is configured such that the output, that is, the rotational speed can be arbitrarily controlled by the ECU 6 variably controlling the ON duty ratio of the drive signal pulse signal. When the water temperature sensor 7 detects the temperature of the cooling water flowing through the water jacket, the temperature information is input to the ECU 6, and the ECU 6 is configured to control the output of the electric fan 9 based on this temperature information.

  In the circuit connecting the engine 2, the water pump 4, and the heater 5, cooling water (hot water) is circulated by the water pump 4. The heater 5 is disposed in an air conditioning case of an air conditioning unit (not shown), and heats conditioned air blown by a blower (not shown) by heat exchange with cooling water (hot water).

  The way in which the cooling water flows changes depending on the temperature. When the cooling water temperature is relatively low, such as immediately after the engine 2 is started, the electric thermostat 3 is closed. Therefore, the cooling water that has flowed out of the engine 2 due to the suction of the water pump 4 passes through the heater 5 and passes through the heater outlet side passage. 11 and after passing through the radiator inlet side passage 12 and the bypass passage 13 without flowing to the heater 5, the flow passes through the merging portion 15 and passes through the water pump 4 to the engine 2. Return.

  On the other hand, when the cooling water temperature becomes relatively high, the electric thermostat 3 opens, and the cooling water flowing out of the engine 2 due to the suction of the water pump 4 mainly flows into the radiator 1 and is cooled, and passes through the water pump 4. Return to engine 2. At the same time, the amount of cooling water flowing into the radiator 1 is not as large as the amount of cooling water flowing into the radiator 1, but by the suction of the water pump 4, the cooling water flows back to the engine 2 through the bypass passage 13 and the engine 2 through the heater 5. A flow of cooling water is generated. The electric thermostat 3 is configured to open the passage when the coolant temperature detected by the coolant temperature sensor 7 exceeds a predetermined temperature.

  Next, the control of the electric thermostat 3 performed by the engine cooling apparatus having the above configuration will be described in detail.

  In a situation where the cooling water does not flow uniformly in the radiator 1, there may be a drift where the flow is uneven. When such a drift occurs, if the cooling water flowing into the radiator 1 increases, the cooling water further flows into the drift part, and the temperature difference between the drift part and the non-slip part further expands, resulting in thermal distortion. Will be promoted. In particular, when the cooling water is forcibly circulated by a mechanical pump, the flow rate of the cooling water flowing into the radiator 1 increases when the vehicle accelerates, and the acceleration of thermal distortion becomes significant. Therefore, when the vehicle accelerates from the idling state, the flow rate of the cooling water flowing in increases, so it is necessary to appropriately control the flow rate of the cooling water.

  On the other hand, the cooling water flows through a water jacket inside the engine 2, and a temperature difference is generated between the outlet and the inlet of the engine 2. This temperature difference needs to be kept within a predetermined range, and for that purpose, a certain amount or more of cooling water must be circulated, so that it is impossible to stop the circulation of cooling water unnecessarily in order to control the circulation flow rate of the cooling water. .

  Therefore, the engine cooling device of the present embodiment controls the flow rate of the cooling water to the radiator 1 by the electric thermostat 3 without reducing the circulating flow rate in the engine 2 with the flow shown in FIG. .

  When the engine 2 is started, the ECU 6 first acquires an accelerator signal (step S100). Then, the ECU 6 determines whether or not acceleration is started based on the acquired accelerator signal (step S110). When the ECU 6 determines that acceleration has started, it performs control to stop the flow of the cooling water to the radiator 1 (step S120). If the ECU 6 determines that acceleration has not started or has not reached the level of acceleration, the ECU 6 obtains an accelerator signal again and repeats the determination in step S110.

  Specifically, the ECU 6 closes the electric thermostat 3. Accordingly, the cooling water does not flow from the radiator inlet-side passage 12 to the route from the radiator 1 to the radiator outlet-side passage 14, but from the passage through the bypass passage 13 or the water jacket to the heater outlet-side passage 11 via the heater 5. It will flow to the route that leads to.

  After acceleration, as long as the cooling water temperature of the engine 2 permits, that is, while the cooling water temperature is not in an abnormal state, the flow of water to the radiator 1 is stopped, and a drift that can occur in the radiator 1 is caused by the vehicle speed. It is controlled so as to be extinguished using cooling air.

  In addition, this control allows the flow rate of the cooling water that is about to flow into the radiator 1 due to acceleration of the vehicle to escape to the bypass passage 13 and the heater 5. Further, when control is performed so that more cooling water flows to the heater 5 side than to the bypass passage 13 side, the amount of heat released from the heater 5 increases, so that the increase of the cooling water temperature in the engine 2 can be delayed. In particular, this control has a remarkable effect because it can temporarily limit the flow rate of cooling water flowing into the radiator 1 when accelerating from an idling state.

  Subsequently, after confirming the elapse of a certain time (step S130), the ECU 6 performs control to gradually carry out the flow of cooling water to the radiator 1 (step S140), and ends this control. Specifically, the ECU 6 performs control to gradually increase the opening of the electric thermostat 3. The control for gradually increasing the opening is, for example, increasing the opening linearly or repeatedly increasing the opening by a certain amount in multiple steps.

  This control is intended to suppress thermal distortion by starting softly without starting to increase the inflow flow rate suddenly after starting water flow to the radiator 1. In the series of controls up to this point, when a situation occurs in which the cooling water temperature exceeds the allowable value, the fail-safe function is activated to stop this control, and water is actively passed to the radiator 1. And

  As described above, in the engine cooling device of the present embodiment, when the ECU 6 recognizes the acceleration of the vehicle, the electric thermostat 3 is once closed, and after the predetermined time has elapsed, the opening degree of the electric thermostat 3 is gradually increased. The flow rate of the cooling water is controlled.

  According to the flow rate control and the electric thermostat 3, in a situation where a load is easily applied to the engine 2, by controlling the circulation flow rate of the cooling water in the engine 2 to stop the water flow to the radiator 1, Thermal distortion can be suppressed by reducing the drift by the cooling air to the radiator 1 and further increasing the flow rate after stopping the water flow.

(Second Embodiment)
The engine cooling device of the present embodiment is characterized in that the control flow shown in FIG. 2 is executed after the steps S200 to S310 shown in FIG. 3 are executed in the flow of cooling water flow control performed by control of the electric thermostat 3. This is different from the first embodiment. FIG. 3 is a flowchart showing the flow rate control of the cooling water by the electric thermostat or the engine cooling device in the present embodiment. The configuration of the engine cooling device is shown in FIG. 1 as in the first embodiment.

  The operation of the electric thermostat 3 in the engine cooling device of this embodiment will be described with reference to FIG. When the engine 2 is started, the ECU 6 first starts normal control of the electric thermostat 3 (step S200). This normal control is to control the opening degree of the electric thermostat 3 by the ECU 6 so that the temperature of the cooling water approaches the set target value. For example, PID control is used.

  Then, the ECU 6 determines whether or not the electric thermostat 3 is open (step S300). The ECU 6 repeats step S300 until it is determined that the electric thermostat 3 is open, and if it is determined that the electric thermostat 3 is open, it determines whether or not the outside air temperature is below a predetermined value TA (step S310). The outside air temperature is detected by an outside air temperature sensor among various sensors input to the ECU 6. The predetermined value TA is, for example, −10 ° C., and it is preferable to detect a cryogenic environment. When it is determined that the outside air temperature is not lower than the predetermined value TA, the process returns to step S300.

  When the ECU 6 determines that the outside air temperature is lower than the predetermined value, the control jumps to step S100 shown in FIG. 2 to start control for restricting the flow of the cooling water to the radiator 1, and the control of S100 to S140 described above is performed. A flow is executed (step S400).

  As described above, the engine cooling device of the present embodiment shifts to the flow rate control of the cooling water described in the first embodiment when the outside air temperature falls below the predetermined value TA. When this flow control and the electric thermostat 3 are adopted, the circulation amount of the cooling water to the radiator 1 is limited when the outside air temperature is a low temperature, particularly an extremely low temperature, below the predetermined value TA. It is possible to suppress the drift by detecting a situation in which the drift is likely to occur due to a decrease in the viscosity of the liquid.

(Third embodiment)
The engine cooling device according to the present embodiment performs the control flow shown in FIG. 2 after executing steps S200 to S320 shown in FIG. 4 in the flow of cooling water flow control performed by the control of the electric thermostat 3. This is different from the first embodiment. In other words, the present embodiment is different from the second embodiment in that S320 is executed instead of step S310. FIG. 4 is a flowchart showing the flow rate control of the cooling water by the electric thermostat or the engine cooling device in the present embodiment. The configuration of the engine cooling device is shown in FIG. 1 as in the first embodiment.

  The operation of the electric thermostat 3 in the engine cooling device of this embodiment will be described with reference to FIG. When the engine 2 is started, the ECU 6 executes steps S200 and S300 in the same manner as in the control flow in the second embodiment. When the ECU 6 determines that the electric thermostat 3 is open, the ECU 6 determines whether or not the rotational speed of the engine 2 is below a predetermined value R (step S320). The predetermined value R is, for example, 1500 rpm, and is preferably in an idling state. When it is determined that the rotational speed of the engine 2 is not less than the predetermined value R, the process returns to step S300.

  When the ECU 6 determines that the rotational speed of the engine 2 is lower than the predetermined value R, the ECU 6 jumps to step S100 shown in FIG. 2 to start control for restricting the flow of the cooling water to the radiator 1, and the above-described S100. The control flow of S140 is executed (step S400).

  As described above, the engine cooling device of this embodiment shifts to the flow rate control of the cooling water described in the first embodiment when the rotational speed of the engine 2 falls below a predetermined value. When this flow control and the electric thermostat 3 are adopted, the circulation amount of the cooling water to the radiator 1 is limited when the rotational speed of the engine 2 is lower than a predetermined value, so that the amount of water flowing to the radiator 1 is small. It is possible to suppress the drift by detecting the situation in which the drift is likely to occur.

(Fourth embodiment)
The engine cooling device of the present embodiment is characterized in that the control flow shown in FIG. 2 is executed after steps S200 to S330 shown in FIG. 5 are executed in the flow of cooling water flow control performed by the control of the electric thermostat 3. This is different from the first embodiment. In other words, the present embodiment is different from the second embodiment in that S330 is executed instead of step S310. FIG. 5 is a flowchart showing the flow rate control of the cooling water by the electric thermostat or the engine cooling device in the present embodiment. The configuration of the engine cooling device is shown in FIG. 1 as in the first embodiment.

  The operation of the electric thermostat 3 in the engine cooling device of this embodiment will be described with reference to FIG. When the engine 2 is started, the ECU 6 executes steps S200 and S300 in the same order as in the control flow in the second embodiment. When the ECU 6 determines that the electric thermostat 3 is open, the ECU 6 determines whether or not the vehicle speed is below a predetermined value S (step S330). The predetermined value S is, for example, 15 km / h, and is preferably during slow driving or slow running. When it is determined that the vehicle speed is not lower than the predetermined value S, the process returns to step S300.

  When the ECU 6 determines that the vehicle speed is lower than the predetermined value S, the control jumps to step S100 shown in FIG. 2 to start control for restricting the flow of the cooling water to the radiator 1, and the control of the above-described S100 to S140 is performed. A flow is executed (step S400).

  As described above, when the vehicle speed falls below the predetermined value S, the engine cooling device of the present embodiment shifts to the flow rate control of the cooling water described in the first embodiment. When this flow control and the electric thermostat 3 are adopted, when the vehicle speed falls below a predetermined value, the circulation amount of the cooling water to the radiator 1 is limited, so that a drift occurs due to the small amount of ventilation to the radiator 1. The situation where it is easy to detect can be detected and drift can be suppressed.

(Fifth embodiment)
The engine cooling device of the present embodiment is characterized in that, in the flow of cooling water flow control performed by control of the electric thermostat 3, after executing steps S200 to S330 shown in FIG. 6, the control flow shown in FIG. 2 is executed. This is different from the first embodiment. In other words, this embodiment is different from the second embodiment in that step S320 of the third embodiment and step S330 of the fourth embodiment are executed in order in addition to step S310. FIG. 6 is a flowchart showing the flow rate control of the cooling water by the electric thermostat or the engine cooling device in the present embodiment. The configuration of the engine cooling device is shown in FIG. 1 as in the first embodiment.

  The operation of the electric thermostat 3 in the engine cooling device of this embodiment will be described with reference to FIG. When the engine 2 is started, the ECU 6 executes steps S200, S300, and S310 in the same order as in the control flow in the second embodiment. Then, when the outside air temperature is lower than the predetermined value TA in step S310, the ECU 6 executes the above-described steps S320 and S330 in order, and determines that all of steps S310, S320, and S330 are YES. In order to start control for restricting water flow to the radiator 1 of the cooling water, the process jumps to step S100 shown in FIG. 2 and executes the control flow of S100 to S140 described above (step S400). Note that if any one of steps S310, S320, and S330 is NO, the ECU 6 repeats execution until all are YES.

  As described above, the engine cooling device of the present embodiment satisfies all the conditions that the outside air temperature is lower than the predetermined value, the rotational speed of the engine 2 is lower than the predetermined value, and the vehicle speed is lower than the predetermined value. In addition, it is assumed that the flow of cooling water described in the first embodiment is shifted to control.

  The drift of the cooling water passed to the radiator 1 has a low flow rate to the radiator 1 and a radiator passing wind speed, and has a high probability of being generated at an extremely low temperature. The flow rate inside the engine 2, the radiator passing wind speed, and the outside air temperature can be estimated from signals from various sensors input to the ECU 6.

  Therefore, when this flow control and the electric thermostat 3 are adopted, the occurrence of the drift can be determined by estimating the drift generation condition by detecting each data. In addition, since the number of times of driving the electric thermostat 3 can be reduced, it is possible to ensure an appropriate service life by eliminating unnecessary driving of the control valve.

It is explanatory drawing which shows the structure of the engine cooling device concerning 1st, 2nd, 3rd, 4th, and 5th Embodiment of this invention. It is a flowchart which shows the flow control of the cooling water by the electric thermostat or engine cooling device in 1st, 2nd, 3rd, 4th, and 5th embodiment. It is a flowchart which shows the flow control of the cooling water by the electric thermostat or engine cooling device in 2nd Embodiment. It is a flowchart which shows the flow control of the cooling water by the electric thermostat or engine cooling device in 3rd Embodiment. It is a flowchart which shows the flow control of the cooling water by the electric thermostat or engine cooling device in 4th Embodiment. It is a flowchart which shows the flow control of the cooling water by the electric thermostat or engine cooling device in 5th Embodiment.

Explanation of symbols

1 Radiator 2 Engine 3 Electric thermostat (electronically controlled flow control valve)
4 Water pump 6 ECU (control means)
12 Radiator inlet side passage (Radiator circuit)
13 Bypass passage (radiator circuit)
14 Radiator outlet side passage (Radiator circuit)

Claims (10)

A radiator (1) connected to the water jacket of the engine (2);
A radiator circuit (12, 13, 14) formed to communicate the radiator (1) and the engine (2);
A water pump (4) for forcibly circulating cooling water through the radiator circuit (12, 13, 14);
An electronically controlled flow control valve (3) for controlling the flow rate of cooling water to the radiator (1);
Control means (6) for controlling at least the electronically controlled flow control valve (3),
When the control means (6) recognizes the acceleration of the vehicle, the electronic control flow control valve (3) is closed once, and after a predetermined time has elapsed, the opening degree of the electronic control flow control valve (3) is gradually increased. An engine cooling device for controlling the flow rate of cooling water by increasing the flow rate.   The engine cooling apparatus according to claim 1, wherein the transition condition to the flow rate control of the cooling water is when an outside air temperature falls below a predetermined value.   2. The engine cooling device according to claim 1, wherein the transition condition to the flow rate control of the cooling water is when the rotational speed of the engine (2) falls below a predetermined value.   The engine cooling apparatus according to claim 1, wherein the transition condition to the flow rate control of the cooling water is when a vehicle speed falls below a predetermined value.   The engine cooling apparatus according to claim 1, wherein the condition for shifting to the flow rate control of the cooling water is when all of the conditions according to claim 2, 3, and 4 are satisfied. An electronically controlled flow control valve (3) for controlling the flow rate of cooling water of the engine (2) forcedly sent by the water pump (4) into the radiator (1),
An electronically controlled flow control valve characterized in that the flow rate of cooling water is controlled by closing the valve once when the vehicle accelerates and gradually increasing the opening after a predetermined time has elapsed.   The electronically controlled flow control valve according to claim 6, wherein the transition condition to the flow control of the cooling water is set when the outside air temperature falls below a predetermined value.   The electronically controlled flow control valve according to claim 6, wherein the condition for shifting to the flow control of the cooling water is when the rotational speed of the engine (2) falls below a predetermined value.   The electronically controlled flow control valve according to claim 6, wherein the transition condition to the flow control of the cooling water is set when the vehicle speed falls below a predetermined value.   The electronically controlled flow control valve according to claim 6, wherein the condition for shifting to the flow control of the cooling water is when all of the conditions described in claims 7, 8, and 9 are satisfied.

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