JP5845145B2 - Cooling control device for internal combustion engine - Google Patents

Description

  The present invention relates to an apparatus for controlling a system for cooling an internal combustion engine, and more particularly to an apparatus for controlling circulation of cooling water.

  The internal combustion engine generates heat due to the combustion of fuel, and if the temperature becomes excessively high, the efficiency deteriorates due to abnormal combustion or the like, and therefore, a cooling device is provided. As a cooling method of the internal combustion engine by the cooling device, a water cooling type using water as a refrigerant, an oil cooling type using oil instead of water, an air cooling type using air as a refrigerant, and the like are known. In any type, if the internal combustion engine is not sufficiently cooled by the cooling device, the above-described abnormal combustion occurs, and conversely, if the cooling is excessive, combustion of the fuel is hindered. In the following description, the internal combustion engine is referred to as an engine.

  For example, Patent Literature 1 describes a cooling device for a hybrid car engine that includes an engine and a motor as driving force sources. The cooling device described in Patent Document 1 includes a radiator circuit that returns cooling water flowing out from the water jacket of the engine to the water jacket again through the radiator, and a bypass that bypasses the radiator and returns the cooling water to the water jacket. A circuit and a heater circuit for returning the cooling water to the water jacket after flowing the heater of the air conditioner are provided. Moreover, the switching valve which switches those circuits is provided. This switching valve is configured by a rotary valve or a spool valve, for example, and is configured to close the radiator circuit and the heater circuit and open the radiator circuit when the engine is not warmed up sufficiently, for example. On the other hand, when the engine is sufficiently warmed up, each circuit described above is opened.

JP 2002-276362 A

  As the switching valve described in Patent Document 1, it is conceivable to use an electromagnetic switching valve. The electromagnetic switching valve is configured to move the valve body by applying an electromagnetic force against the elastic force to the valve body that receives the elastic force of the spring, and by changing the magnitude of the electromagnetic force The opening can be arbitrarily set. However, when foreign matter such as iron powder is mixed in the cooling water, the electromagnetic switching valve easily attracts the foreign matter by the electromagnetic force. If foreign matter accumulates on the electromagnetic switching valve, the accumulated foreign matter may hinder the opening / closing operation of the electromagnetic switching valve.

  The present invention has been made paying attention to the above technical problem, and ensures the opening / closing operation of the electromagnetic switching valve in the cooling control device for an internal combustion engine that employs the electromagnetic switching valve as a valve for switching the circuit of the cooling water. It is for the purpose.

In order to achieve the above-mentioned object , the present invention reduces the amount of cooling water circulating through the circuit by applying a voltage to the circuit in which the cooling water is circulated between the water pump and the internal combustion engine to reduce the opening. In the cooling control device for an internal combustion engine provided with an electromagnetic switching valve configured to increase the amount of cooling water by decreasing and cutting off the voltage to increase the opening degree, the electromagnetic switching valve includes: Estimating the amount of foreign matter accumulated in the electromagnetic switching valve with the opening reduced, having a flow part for circulating a small amount of the cooling water so as to bypass the electromagnetic switching valve when the opening is reduced. when the estimated value of the accumulation amount of vital the foreign substance is not less than the threshold value a predetermined, e Bei the valve opening means for increasing the opening degree, the valve opening means, terminates the vehicle equipped with the internal combustion engine is running And the foreign matter When the estimated value of the product quantity is greater than zero, the increase the degree of opening of the electromagnetic switching valve, and is characterized in it to contain means for subsequently driving the water pump.

The front KiHirakiben device in this inventions, the when increased the degree of opening of the electromagnetic switching valve may include means for resetting the estimate of the accumulated amount of the foreign objects to zero.

Furthermore, before KiHirakiben device in this inventions may include a means for increasing the opening degree of the electromagnetic selector valve when the time of applying the voltage to the electromagnetic switching valve exceeds a predetermined time .

Then, before KiHirakiben device in this inventions is the amount of time applying the voltage to be compared with the predetermined time, to calculate on the basis of actually the time of applying a voltage to the electromagnetic switching valve, said actual In addition, it may include means for correcting so that the time calculated based on the time when the voltage is applied to the electromagnetic switching valve becomes longer as the discharge amount of the water pump increases .
Further, the present invention reduces the amount of cooling water circulating in the circuit by applying a voltage to the circuit in which the cooling water is circulated between the water pump and the internal combustion engine to reduce the opening, and cuts off the voltage. In the cooling control device for an internal combustion engine provided with an electromagnetic switching valve configured to increase the amount of cooling water by increasing the opening, the electromagnetic switching valve reduces the opening. A flow part for circulating a small amount of the cooling water so as to bypass the electromagnetic switching valve, and estimating the amount of foreign matter accumulated in the electromagnetic switching valve having a reduced opening degree and the amount of foreign matter accumulated When the estimated value is equal to or greater than a predetermined threshold value, the valve opening means increases the opening, and the valve opening means exceeds a predetermined time when the voltage is applied to the electromagnetic switching valve. When said electromagnetic Including a means for increasing the opening of the replacement valve, and calculating the time for applying the voltage to be compared with the predetermined time based on the time for actually applying the voltage to the electromagnetic switching valve, It is characterized by including means for correcting so that the time calculated based on the time when the voltage is actually applied to the electromagnetic switching valve becomes longer as the discharge amount of the water pump increases.

According to the present invention, the electromagnetic switching valve has the circulation part that circulates a small amount of cooling water so as to bypass the electromagnetic switching valve when the opening is reduced. Even so, a small amount of cooling water circulates in the circuit between the water pump and the internal combustion engine. Therefore, for example, when the opening degree of the electromagnetic switching valve is reduced in order to promote warm-up of the internal combustion engine, it is possible to prevent or suppress the temperature of the cooling water from rising locally inside the water jacket. it can. On the other hand, when foreign matter accumulates on the electromagnetic switching valve by applying a voltage to the electromagnetic switching valve, when the estimated value of the accumulation amount exceeds a predetermined threshold value, the opening degree is increased to Foreign matter can be washed away by cooling water. For this reason, it is possible to prevent or suppress foreign matters having a threshold value or more from accumulating on the electromagnetic switching valve and preventing the accumulated switching foreign matter from opening and closing the electromagnetic switching valve. In addition, it is possible to prevent the accumulated foreign matter from gathering into a large lump. Thus, since the foreign matter is washed away by the cooling water before the foreign matter accumulated on the electromagnetic switching valve becomes a large lump, it becomes a large lump in the cooling circuit on the downstream side of the electromagnetic switching valve in the flow direction of the cooling water. It is possible to prevent foreign matters from being clogged . Further, when the vehicle finishes traveling, the foreign matter accumulated on the electromagnetic switching valve is washed away by the cooling water, so that when the vehicle is restarted after that, the foreign matter is not accumulated on the electromagnetic switching valve. can do.

Further, according to this invention, when increasing the opening of the conductive magnetic switching valve, by resetting the estimate of foreign matter accumulation amount to zero, the last to estimate the deposition amount of this foreign matter foreign matter It is possible to prevent the estimated value of the amount of deposition from being added.

Further, according to the present invention, if the time the application of the voltage exceeds a predetermined time, the opening degree of the solenoid-operated change-over valve is increased. That is, the opening degree of the electromagnetic switching valve can be periodically increased to remove foreign matter.

Then, according to the present invention, the more the discharge amount of c Otaponpu, the time of applying the voltage is increased to the electromagnetic switching valve that is compared with a predetermined time. That is, as the discharge amount of the water pump increases, the opening of the electromagnetic switching valve increases to shorten the cycle for removing foreign matter. Therefore, even if the amount of foreign matter flowing to the electromagnetic switching valve increases with an increase in the discharge amount of the water pump, excessive accumulation of foreign matter on the electromagnetic switching valve can be prevented or suppressed. Further, as described above, since the time during which the voltage is applied to the electromagnetic switching valve to be compared with the predetermined time is changed, the predetermined time that is the object of comparison can be made one, and accordingly The amount of memory in the control device can be reduced.

It is a flowchart which shows an example of the control by the cooling control apparatus of the internal combustion engine which concerns on this invention. It is a time chart for demonstrating the change of the quantity of the foreign material deposited on the electromagnetic switching valve at the time of performing control by the cooling control apparatus of the internal combustion engine which concerns on this invention. It is a figure which shows typically an example of the electromagnetic switching valve in this invention. It is a figure which shows typically the state which the electromagnetic switching valve in this invention has opened. It is a figure which shows typically an example of the cooling control apparatus of the internal combustion engine which concerns on this invention.

  Next, the present invention will be specifically described. FIG. 5 is a diagram schematically showing an example of a cooling control apparatus for an internal combustion engine according to the present invention. A water jacket (not shown) is provided on the cylinder block and cylinder head of the engine 1. The water jacket cools the engine 1 by transferring heat generated in the engine 1 to cooling water. An electric water pump 2 for supplying cooling water to the water jacket is provided. Although not shown in detail, the water pump 2 includes an impeller that is rotated to send cooling water, and a motor that rotates the impeller. The flow rate and discharge pressure of the cooling water discharged from the water pump 2 can be changed by electrically controlling the rotation of the motor.

  The configuration of the water pump 2 will be briefly described. Although not shown in detail, the water pump 2 has a PWM (Pulse Width Modulation) circuit. The PWM circuit is a circuit for duty-controlling the rotational speed of the motor of the water pump 2 in accordance with a control signal output from an electronic control device to be described later. For example, when the driving duty output to the motor of the water pump 2 is increased, the rotational speed of the motor is increased, and when the driving duty is decreased, the rotational speed of the motor is decreased.

  The discharge port of the water pump 2 and the water jacket are connected by a supply line 3, and the suction port of the water pump 2 and the water jacket are connected by a return line 4. As shown in FIG. 5, the supply pipe 3 and the return pipe 4 form a cooling water circulation circuit. This circulation line corresponds to the circuit in the present invention.

  An electromagnetic switching valve 5 is provided in the return line 4. The electromagnetic switching valve 5 is configured such that a voltage is applied to reduce the opening, and the voltage is interrupted to increase the opening. In the example shown in FIG. 5, the electromagnetic switching valve 5 is configured to switch the circuit through which the cooling water circulates from the circulation circuit described above to a circuit that passes through a radiator described later by reducing the opening degree. In addition, as will be described later, the electromagnetic switching valve 5 has a circulation part through which a small amount of cooling water passes even when the opening degree is reduced, and a small amount of cooling water passes through the circulation part. The circuit is configured to circulate. Although not shown in detail, the electromagnetic switching valve 5 is electrically connected to the auxiliary battery. The auxiliary battery is a power source for operating auxiliary machines such as a headlight and an air conditioner mounted on the vehicle, and is connected to the main battery via a DC-DC converter.

  A thermostat 6 is provided in the return line 4. The thermostat 6 allows the cooling water to flow to the radiator when the temperature of the cooling water is equal to or higher than a predetermined temperature, and conversely, when the temperature of the cooling water is lower than the predetermined temperature, The distribution of cooling water is prohibited. The configuration of the thermostat 6 is the same as that conventionally known. The above-mentioned predetermined temperature is a temperature for determining whether or not the warm-up of the engine 1 is completed as an example, and the temperature is referred to as a warm-up temperature in the following description. The thermostat 6 always allows the cooling water flowing through the return pipe 4 to pass through the electromagnetic switching valve 5.

  A radiator 8 is provided in a cooling line 7 branched from the return line 4. The radiator 8 is configured to cool the cooling water whose temperature has been increased by taking heat of the engine 1 by exchanging heat between the cooling water and the outside air. It is the same. The cooling water cooled by the radiator 8 is supplied to the suction port of the water pump 2 via the thermostat 6.

  An electronic control device 9 for electrically controlling the electromagnetic switching valve 5 and the water pump 2 is provided. This will be referred to as ECU 9 in the following description. The ECU 9 is configured mainly with a microcomputer as an example, and performs an operation based on input data or data stored in advance and outputs a control signal as a result of the operation to the electromagnetic switching valve 5. It is configured as follows. The ECU 9 includes, for example, a water temperature sensor that detects the temperature of the cooling water, an engine speed sensor that detects the rotational speed of the output shaft of the engine, a throttle position sensor that detects the opening of the throttle valve, and an electric storage such as a battery or a capacitor. Detection signals from various sensors such as a charge sensor for detecting the charging state of the apparatus are input.

  FIG. 3 is a diagram schematically showing an example of the electromagnetic switching valve in the present invention. The electromagnetic switching valve 5 includes a cylinder portion 10. An input port 11 connected to the discharge port of the water pump 2 via a water jacket and an output port 12 connected to the suction port of the water pump 2 are formed in the cylinder portion 10. An accommodation chamber 14 is formed in the cylinder portion 10 to accommodate the valve body 13 so as to be movable back and forth in the axial direction. The inner diameter of the accommodation chamber 14 is formed larger than the inner diameters of the input port 11 and the output port 12.

  The valve body 13 is configured to be pressed against the inner wall surface of the storage chamber 14 on the input port 11 side to close the input port 11. The shape of the valve body 13 is, for example, a disk shape having a diameter larger than the inner diameter of the input port 11 and the output port 12 and smaller than the inner diameter of the storage chamber 14. In the example shown in FIG. 3, a circulation portion 15 that penetrates the valve body 13 is formed in the center of the valve body 13. The flow part 15 may be configured to cut out a part of the outer peripheral side of the valve body 13 so as to communicate the input port 11 and the output port 12. The circulation unit 15 may be a pipe that bypasses the valve body 13 and connects the input port 11 and the output port 12.

  The inner wall surface of the storage chamber 14 on the input port 11 side described above serves as a valve seat portion 16 to which the valve body 13 is pressed. A spring 17 is provided that moves the valve body 13 away from the valve seat portion 16 and moves it to the output port 12 side. One end of the spring 17 is integrated with the valve body 13, and the other end is integrated with the inner wall surface of the storage chamber 14 on the output port 12 side.

  An electromagnetic coil portion 18 is provided to attract the valve body 13 to the valve seat portion 16 against the elastic force of the spring 17. The electromagnetic coil unit 18 is configured to generate an electromagnetic force corresponding to the voltage value by applying a voltage to an electromagnetic coil (not shown). In addition, a core 19 that functions to expand the range in which the electromagnetic force generated in the electromagnetic coil section 18 acts is provided. The core 19 is magnetized by the electromagnetic force of the electromagnetic coil portion 18 to generate a magnetic force.

  When the magnetic force generated in the electromagnetic coil unit 18 and the core 19 is larger than the elastic force of the spring 17, the valve body 13 is moved to the input port 11 side by the magnetic force. Further, when the magnetic force is sufficiently larger than the elastic force of the spring 17, the valve body 13 is pressed against the valve seat portion 16. In this state, the input port 11 and the output port 12 communicate with each other through the circulation unit 15. This state is referred to as a valve closing state in the following description. On the contrary, when the elastic force of the spring 17 is larger than the magnetic force, the valve body 13 is moved to the output port 12 side by the elastic force of the spring 17, and the input port 11 and the output port 12 are communicated. Open the valve. This state is referred to as a valve open state in the following description.

  FIG. 4 is a diagram schematically showing a state in which the electromagnetic switching valve 5 is opened in the present invention. The electromagnetic switching valve 5 changes the duty ratio by changing the ratio between the state where the voltage is applied to the electromagnetic coil unit 18 and the state where the voltage is cut off within a predetermined time. By doing so, as shown in FIG. 4, the opening degree can be arbitrarily set.

  Next, the operation of the internal combustion engine cooling control apparatus having the configuration shown in FIG. 5 will be briefly described. When the temperature of the engine 1 is low and the temperature of the cooling water is lower than the warm-up temperature, such as immediately after starting the engine 1, the circulation of the cooling water to the radiator 8 is prohibited by the thermostat 6. On the other hand, in order to promote warm-up of the engine 1, the electromagnetic switching valve 5 is applied with a voltage to the electromagnetic coil portion 18 and is in a closed state. Therefore, a small amount of cooling water that has passed through the circulation part 15 flows in the circulation circuit.

  When the temperature of the cooling water is higher than another temperature slightly lower than the warming-up temperature and lower than the warming-up temperature, the cooling water is still lower than the warming-up temperature, and the circulation of the cooling water to the radiator 8 is performed by the thermostat 6. It is prohibited by The other temperature is referred to as a semi-warm-up temperature in the following description. On the other hand, since the temperature of the cooling water is equal to or higher than the semi-warm-up temperature, the voltage to the electromagnetic coil unit 18 of the electromagnetic switching valve 5 is cut off, and the electromagnetic switching valve 5 is in the open state. As a result, the amount of cooling water circulating in the circulation circuit increases, so that the cooling water temperature rises gradually.

  When the temperature of the cooling water is equal to or higher than the warm-up temperature, the cooling water is allowed to flow to the radiator 8 by the thermostat 6. Further, the electromagnetic switching valve 5 is open. Therefore, a part of the cooling water is supplied to the radiator 8 and cooled. The remaining cooling water is circulated through the electromagnetic switching valve 5.

  The present invention is configured to execute the following control when foreign matter such as iron powder accumulates on the surface of the core 19 due to the magnetic force generated in the electromagnetic coil portion 18 and the core 19 of the electromagnetic switching valve 5. FIG. 1 is a flowchart for explaining an example of the control, and the routine shown here is repeatedly executed at predetermined intervals. First, it is determined whether or not a voltage is applied to the electromagnetic coil portion 18 of the electromagnetic switching valve 5 (step S1). This can be performed by detecting a voltage value applied to the electromagnetic coil unit 18 with a voltage sensor (not shown).

  When a positive determination is made in step S1 by applying a voltage to the electromagnetic coil unit 18, the flow rate of the cooling water flowing through the flow unit 15 is calculated from the discharge amount of the water pump 2 (step S2). ). For example, the amount of cooling water passing through the circulation portion 15 corresponding to the discharge amount of the water pump 2 may be prepared in advance as a map, and the above-described amount of cooling water may be obtained using the map.

  Subsequent to or in parallel with the control in step S2, the amount of foreign matter deposited on the surface of the core 19 is estimated (step S3). The estimation of the amount of accumulated foreign matter is not shown in detail, but as an example, the elapsed time from the start of running of the vehicle and the application of voltage to the electromagnetic switching valve 5, the amount of cooling water flowing through the circulation portion 15, etc. The estimated value of the amount of accumulated foreign matter corresponding to the above may be prepared in advance as a map, and the estimated value of the amount of accumulated foreign matter may be obtained using the map. Next, it is determined whether or not the estimated value of the amount of accumulated foreign matter estimated in step S3 exceeds a predetermined threshold value (step S4).

  When the estimated value of the amount of accumulated foreign matter exceeds the threshold value and the determination in step S4 is affirmative, the electromagnetic switching valve 5 is opened (step S5). Specifically, in step S5, the foreign matter is pushed away by the flow of the cooling water in a state where the voltage is cut off and the above-described magnetic force is lost. In addition to cutting off the voltage, the drive duty of the water pump 2 may be increased. If the drive duty of the water pump 2 is increased, the flow rate and the water pressure of the cooling water flowing through the electromagnetic switching valve 5 are increased, so that foreign matters can be pushed away more effectively. When it is determined negative in step S4 because the estimated value of the amount of accumulated foreign matter does not exceed the threshold value, the closed state of the electromagnetic switching valve 5 is maintained (step S6).

  When it is determined negative in step S1 described above because the voltage is cut off, the estimated value of the amount of accumulated foreign matter is reset to zero (step S7). Subsequent to the control of step S5 to step S7, it is determined whether or not the vehicle has finished traveling and the estimated value of the amount of accumulated foreign matter exceeds zero (step S8). If it is estimated that there is no foreign matter accumulation amount at the time when the traveling of the vehicle is finished, a negative determination is made in this step S8, and this routine is finished once.

  If it is presumed that foreign matter has accumulated at the time when the vehicle has finished traveling, an affirmative determination is made in step S8, and then the electromagnetic switching valve 5 is opened (step S9). This is the same control as step S5 described above. Next, when the operation of the water pump 2 is stopped due to stopping or parking, the water pump 2 is driven (step S10). That is, the foreign matter is pushed away by the flow of the cooling water in a state where the above-described magnetic force is lost. Thereafter, this routine is temporarily terminated.

  As described above, according to the cooling control apparatus for an internal combustion engine according to the present invention, even if the foreign matter is attracted to the surface of the core 19 by the magnetic force of the electromagnetic coil portion 18 or the core 19, the foreign matter exceeds the threshold value and a large amount. Prior to deposition, the foreign material can be washed away by the cooling water. Therefore, it is possible to prevent or suppress the accumulated foreign matter from obstructing the opening and closing of the electromagnetic switching valve 5. Further, it is possible to prevent the accumulated foreign matter from becoming a large lump, or the large lump foreign matter from blocking each of the pipes described above. Further, when the vehicle finishes traveling, the foreign matter accumulated on the electromagnetic switching valve 5 is washed away by the cooling water in preparation for the subsequent traveling, so that the electromagnetic switching valve 5 can be opened and closed smoothly when the vehicle starts traveling. can do.

In addition, since the foreign material in cooling water moves with the flow of cooling water, if the amount of cooling water flowing through the flow portion 15 increases due to an increase in the discharge amount of the water pump 2, the foreign matter accumulated on the surface of the core 19 The amount will also increase. Therefore, in step S4, instead of comparing the estimated value of the amount of accumulated foreign matter with the threshold value, the elapsed time from the start of running of the vehicle and the start of application of voltage to the electromagnetic switching valve 5 is set in advance. The time may be compared, and when the elapsed time exceeds a predetermined time, it may be determined that the foreign matter is accumulated exceeding the threshold. More specifically, first, a time α for comparison with a predetermined time based on the elapsed time is calculated. The absolute value of the elapsed time may be used as the time α. Next, the time α is corrected so as to increase the time α as the discharge amount of the water pump 2 increases. The corrected time α is denoted as time β. That is, the time β increases as the discharge amount of the water pump 2 increases . Then, the time β is compared with a predetermined time.

  As described above, when the time during which the voltage is applied to the electromagnetic coil unit 18 and the amount of cooling water flowing through the flow unit 15 increase, the foreign matter accumulated on the electromagnetic switching valve 5 increases. Therefore, the same effect as that of the control example shown in FIG. 1 can be obtained by comparing the time β and the predetermined time.

FIG. 2 is a time chart for explaining a change in the amount of foreign matter deposited on the electromagnetic switching valve 5 when control is performed by the cooling control apparatus for an internal combustion engine according to the present invention. At the time of time t _1, the running of the vehicle is started. A voltage is applied to the electromagnetic switching valve 5 in order to promote warm-up of the engine 1, and its opening degree is reduced. On the other hand, the water pump 2 is driven. Therefore, a small amount of cooling water circulates through the circulation circuit through the circulation part 15. As time passes, foreign matter accumulates on the surface of the core 19.

At the time of time t _2, the temporarily running is terminated by for example vehicle stops. At this time, if the estimated value of the amount of accumulated foreign matter exceeds zero, the voltage to the electromagnetic switching valve 5 is cut off to increase its opening, thereby causing the foreign matter to flow away by the cooling water. Incidentally, at the time of time t _2, the case where the operation of the water pump 2 is stopped, the water pump 2 is driven.

In the time point t _3, the operation of the water pump 2 is stopped. Then, at the time point of time t _4, the running of the vehicle is restarted. A voltage is applied to the electromagnetic switching valve 5 in order to promote warm-up of the engine 1, and its opening degree is reduced. On the other hand, the water pump 2 is driven. Since a small amount of cooling water circulates in the circulation circuit through the circulation part 15, foreign matter accumulates on the surface of the core 19 as time passes. Thereafter, at the time point t _5, for example, when the operation of the water pump 2 is stopped, to stop also the movement of foreign material due to the flow of the cooling water, the deposition amount of the foreign matter does not increase.

In the time point t _6, when the water pump 2 is driven again, over time, the foreign matter is gradually deposited on the surface of the core 19. At the time point t _7, when the estimated value of the foreign matter accumulation amount has exceeded a predetermined threshold value, is cut off the voltage to the electromagnetic switching valve 5, in a state of being lost the above magnetic force, the cooling water The foreign material is pushed away by the flow of.

  Here, the relationship between the above-described specific example and the present invention will be briefly described. The functional means for executing the control of Step S1, Step S3 to Step S5, and Step S8 to Step S10 is “open” in the present invention. It corresponds to “valve means”.

  DESCRIPTION OF SYMBOLS 1 ... Engine, 2 ... Water pump, 5 ... Electromagnetic on-off valve, 15 ... Distribution part.

Claims (5)

A voltage is applied to the circuit in which the cooling water is circulated between the water pump and the internal combustion engine to reduce the opening, thereby reducing the amount of cooling water circulating in the circuit and cutting off the voltage to reduce the opening. In an internal combustion engine cooling control apparatus provided with an electromagnetic switching valve configured to increase the amount of the cooling water by increasing,
The electromagnetic switching valve has a flow part for circulating a small amount of the cooling water so as to bypass the electromagnetic switching valve when the opening degree is reduced,
When the estimated value of the accumulation amount of the estimated amount of accumulated foreign matter in the electromagnetic switching valve and the foreign matter subtracting the opening degree is equal to or more than the threshold value a predetermined, e Bei the valve opening means for increasing the opening ,
The valve opening means increases the opening degree of the electromagnetic switching valve when a vehicle equipped with the internal combustion engine finishes running and the estimated value of the amount of accumulated foreign matter is greater than zero, and then cooling control apparatus for an internal combustion engine, wherein a call includes means for driving the water pump.   2. The internal combustion engine according to claim 1, wherein the valve opening means includes means for resetting an estimated value of the amount of accumulated foreign matter to zero when the opening degree of the electromagnetic switching valve is increased. Cooling control device. It said valve opening means, according to claim 1, characterized in that it comprises means for increasing the opening degree of the electromagnetic selector valve when the time of applying the voltage exceeds a predetermined time before SL solenoid selector valve cooling control apparatus for an internal combustion engine according to. Said valve opening means, the amount of time applying the voltage to be compared with the previous SL predetermined time, to calculate on the basis of actually the time a voltage is applied to the solenoid switching valve, the voltage to the electromagnetic switching valve when said actual 4. The cooling control apparatus for an internal combustion engine according to claim 3, further comprising means for correcting the time calculated based on the time during which the water pump is applied so as to increase as the discharge amount of the water pump increases . A voltage is applied to the circuit in which the cooling water is circulated between the water pump and the internal combustion engine to reduce the opening, thereby reducing the amount of cooling water circulating in the circuit and cutting off the voltage to reduce the opening. In an internal combustion engine cooling control apparatus provided with an electromagnetic switching valve configured to increase the amount of the cooling water by increasing,
The electromagnetic switching valve has a flow part for circulating a small amount of the cooling water so as to bypass the electromagnetic switching valve when the opening degree is reduced,
A valve opening means for estimating the amount of foreign matter accumulated in the electromagnetic switching valve that is reducing the opening degree and increasing the opening degree when the estimated amount of the foreign matter accumulation amount is equal to or greater than a predetermined threshold;
Before KiHirakiben means the includes a means for increasing the opening degree of the electromagnetic selector valve when the time of applying the voltage exceeds a predetermined time the electromagnetic switching valve, and, before Symbol predetermined time The time when the voltage to be compared is applied is calculated based on the time when the voltage is actually applied to the electromagnetic switching valve, and the time is calculated based on the time when the voltage is actually applied to the electromagnetic switching valve. , cooling control device of the internal combustion engine you characterized in that it includes means for correcting to be longer as the discharge amount of the water pump is large.

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