JP2008169750A - Control device for electric water pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device for an electric water pump capable of appropriately avoiding boiling of cooling water while inhibiting wasteful electric power consumption due to the electric water pump. <P>SOLUTION: The control device for the electric water pump controls the electric water pump circulating cooling water in an internal combustion engine. The control device for the electric water pump drives the electric water pump for a predetermined period of time at start of the internal combustion engine. When cooling water temperature obtained when the electric water pump is driven in such a manner is predetermined temperature or lower, it is determined that stop control stopping the electric water pump should be started. Consequently, boiling of cooling water which can occur after start of stop control can be appropriately avoided, and wasteful electric power consumption by the electric water pump can be inhibited since the electric water pump is not driven unnecessarily. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a control device for an electric water pump that controls an electric water pump that circulates engine coolant.

  Conventionally, a technique using an electric water pump (hereinafter referred to as “electric W / P”) that circulates cooling water for cooling an engine has been proposed. For example, Patent Document 1 describes a technique for driving an electric W / P for a predetermined time regardless of the temperature of cooling water when starting an engine. Patent Document 2 describes a technique for controlling the electric W / P so that cooling water is circulated intermittently after a predetermined time has elapsed since startup. Patent Document 3 describes a technique for increasing the rotational speed of the electric W / P according to an increase in the engine speed or the engine load when the temperature of the cooling water at the start is equal to or higher than a predetermined value. Yes.

JP-A-6-117259 JP 2006-214279 A JP 2005-36729 A

  By the way, when starting the engine, it can be said that it is preferable to stop the electric W / P in order to promote warm-up of the engine and power saving. However, when the electric W / P is stopped in this way, it becomes difficult to avoid boiling of the cooling water that may occur when the temperature of the cooling water partially becomes high in the exhaust heat recovery device or the like.

  Here, in the technique described in Patent Document 1 described above, since the electric W / P is driven for a predetermined time at the start, it is considered that boiling of the cooling water can be avoided. However, with this technique, since the electric W / P is driven even in a situation where boiling does not occur, power tends to be wasted. Further, even in the techniques described in Patent Documents 2 and 3, it is difficult to appropriately avoid boiling of the cooling water while suppressing useless power consumption by the electric W / P when starting the engine. .

  The present invention has been made to solve the above-described problems, and appropriately avoids boiling of cooling water while suppressing unnecessary power consumption due to electric W / P at the time of engine start. An object of the present invention is to provide a control device for an electric water pump that can be used.

  In one aspect of the present invention, an electric water pump control device that controls an electric water pump that circulates cooling water in an internal combustion engine is an electric motor that drives the electric water pump for a predetermined time when the internal combustion engine is started. Control for stopping the electric water pump should be started when the temperature of the cooling water when the electric water pump is driven by the water pump driving means and the electric water pump driving means is equal to or lower than a predetermined temperature. When the stop control start determining means and the stop control start determining means determine that the control to stop the electric water pump should be started, the control to stop the electric water pump is executed. Electric water pump stop means.

  The control device for the electric water pump is preferably used for controlling the electric water pump that circulates the cooling water in the internal combustion engine. In this case, the electric water pump drive means drives the electric water pump for a predetermined time when the internal combustion engine is started. Then, the stop control start determination means compares the temperature of the cooling water obtained when the electric water pump is driven in this way with a predetermined temperature, thereby stopping the electric water pump (hereinafter referred to as “ It is also referred to as “stop control”). Specifically, the stop control start determining means determines the possibility that the cooling water will boil based on the temperature of the cooling water, and determines whether stop control should be started based on this. Specifically, when the temperature of the cooling water is equal to or lower than the predetermined temperature, the stop control start determination means determines that the possibility that the cooling water will boil after the stop control is quite low and should start the stop control. Is determined. In this case, the electric water pump stop means executes stop control for the electric water pump. Thereby, it becomes possible to appropriately avoid the boiling of the cooling water that may occur after the start of the stop control of the electric water pump. Further, according to the control device for the electric water pump, the electric water pump is not driven more than necessary (that is, the electric water pump is effectively suppressed from being driven when boiling does not occur). Therefore, useless power consumption by the electric water pump can be suppressed.

  In one aspect of the control apparatus for the electric water pump, the predetermined time for the electric water pump driving means to drive the electric water pump substantially corresponds to a time required for the cooling water to go around the cooling water passage. To do. As a result, wasteful power consumption by the electric water pump can be effectively suppressed, and determination can be made based on the temperature of the cooling water in all the cooling systems, and the cooling water may boil Can be determined appropriately.

  In another aspect of the control device for the electric water pump, when the electric water pump is stopped by the electric water pump stop means, the temperature of the cooling water, the integrated air during the stop of the electric water pump Stop control end determination means for determining whether or not to stop the control of the electric water pump based on at least one of the amount and the stop time of the electric water pump is provided. Accordingly, it is possible to appropriately determine whether the internal combustion engine has been warmed up, and it is possible to end the stop control at an appropriate timing.

  Preferably, in the control device for the electric water pump, the stop control end determination means performs the determination based on an integrated air amount while the electric water pump is stopped, or a stop time of the electric water pump. The determination can be performed using a determination value corresponding to the temperature of the cooling water at the start of stopping the electric water pump.

  In another aspect of the control apparatus for the electric water pump, when the stop time of the electric water pump is longer than a predetermined time, the electric water pump is driven for a predetermined time and the electric water pump is driven. Means for continuously executing the control to stop the electric water pump when the temperature of the cooling water is equal to or lower than a predetermined temperature. As a result, boiling of the cooling water that can occur during the stop control can be appropriately avoided, and the electric water pump is not driven more than necessary, thereby suppressing wasteful power consumption by the electric water pump. Can do.

  Preferred embodiments of the present invention will be described below with reference to the drawings.

[Configuration of cooling system]
FIG. 1 is a diagram showing a schematic configuration of a cooling system 100 to which an electric water pump control device according to an embodiment of the present invention is applied. In FIG. 1, solid arrows indicate the flow of cooling water, and broken arrows indicate input / output of signals. A solid line indicated by a bold line indicates a passage (cooling water passage) through which the cooling water flows.

  The cooling system 100 mainly includes an engine (internal combustion engine) 1, a radiator 3, a thermostat 4, an electric water pump (hereinafter referred to as “electrical W / P”) 5, a water temperature sensor 6, and cooling. Water passages 7a, 7b, 7c and an ECU (Engine Control Unit) 50 are provided.

  The cooling system 100 according to the present embodiment is a system for mainly cooling the engine 1 using cooling water and warming up the engine 1 and the like using cooling water. In this case, the cooling water circulates through the cooling water passages 7a, 7b, and 7c. In the following, when the cooling water passages 7a to 7c are not distinguished from each other, they are simply used as the “cooling water passage 7”.

  The engine 1 is a device that generates power by burning a mixture of supplied fuel and air. The engine 1 is constituted by a gasoline engine, a diesel engine, or the like. The engine 1 supplies the ECU 50 with a signal S1 corresponding to the operating state. For example, an intake air amount (detected by an air flow meter not shown) or the like is supplied to the ECU 50 as the detection signal S1.

  A water temperature sensor 6 for detecting the temperature of the cooling water (hereinafter also referred to as “cooling water temperature”) is provided on the cooling water passage 7a. The water temperature sensor 6 is provided on the cooling water passage 7a on the downstream side of the head (not shown) of the engine 1, for example. The water temperature sensor 6 supplies a detection signal S6 corresponding to the detected temperature to the ECU 50.

  In the radiator 3, the cooling water passing through the inside thereof is cooled by outside air. In this case, cooling of the cooling water in the radiator 3 is promoted by the wind introduced by the rotation of the electric fan (not shown). The electric W / P 5 includes an electric motor, and the cooling water is circulated in the cooling water passage 7 by driving the motor. Specifically, the electric W / P 5 is supplied with electric power from a battery, and the rotational speed and the like are controlled by a control signal S 5 supplied from the ECU 50. In addition, although the example which uses electric W / P5 as a pump which circulates cooling water was shown above, you may use the water pump which can be stopped irrespective of the driving | operation of the engine 1 instead. For example, it is possible to use a water pump that is driven by the rotation of the engine 1 being transmitted via a belt and that can cut the transmission of the rotation from the engine 1 by a clutch.

  The thermostat 4 is configured by a valve that opens and closes according to the temperature of the cooling water. Basically, the thermostat 4 opens when the temperature of the cooling water becomes high. In this case, the cooling water passage 7 b and the cooling water passage 7 c are connected via the thermostat 4, and the cooling water passes through the radiator 3. Thereby, a cooling water is cooled and the overheating of the engine 1 is suppressed. On the other hand, when the temperature of the cooling water is relatively low, the thermostat 4 is closed. In this case, the cooling water does not pass through the radiator 3. Thereby, since the temperature fall of a cooling water is suppressed, the overcool of the engine 1 is suppressed.

  The ECU 50 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like (not shown). The ECU 50 controls the electric W / P 5 based on the output supplied from the various sensors described above. Specifically, the ECU 50 stops the electric W / P 5 at the time of starting the engine 1 in order to promote warm-up of the engine body and the head and to save power (hereinafter simply referred to as “stop control”). I do. In the present embodiment, the ECU 50 determines whether to stop the electric W / P 5 from starting based on the coolant temperature or the like (hereinafter simply referred to as “start determination”) and also performs the stop control. Is determined (hereinafter simply referred to as “end determination”). As described above, the ECU 50 corresponds to the control device for the electric water pump in the present invention. Specifically, the ECU 50 operates as an electric water pump drive unit, a stop control start determination unit, an electric water pump stop unit, and a stop control end determination unit.

[Control method of electric W / P]
Next, a method for controlling the electric W / P 5 performed by the ECU 50 will be described. As described above, when starting the engine 1, the ECU 50 stops the electric W / P 5 so as to stop the flow of the cooling water in order to promote warm-up of the engine body and the head and to save power. Perform control (stop control). In the present embodiment, the ECU 50 performs start determination and end determination of such stop control. Further, the ECU 50 detects the coolant temperature in a predetermined case even during the stop control, and controls the electric W / P 5 based on this. Hereinafter, start determination of stop control, end determination of stop control, and detection of cooling water temperature during stop control will be specifically described.

(Stop control start judgment)
In the present embodiment, the ECU 50 performs stop control start determination so as to avoid occurrence of boiling after the start of stop control. Specifically, the ECU 50 drives the electric W / P 5 for a predetermined time when the engine 1 is started, and determines whether or not to stop the electric W / P 5 based on the coolant temperature detected at this time. Judgment (start judgment) is performed.

  The reason why stop control start determination is performed as described above is as follows. When starting the engine 1, it can be said that it is preferable to stop the electric W / P5 in order to promote warm-up of the engine body and the head and to save power. Thus, when electric W / P5 is stopped, the boiling of the cooling water which may occur when the temperature of the cooling water partially becomes high at the head of the engine 1 or the like becomes a problem. Here, it is conceivable to avoid boiling by detecting the boiling of the cooling water based on the cooling water temperature detected by the water temperature sensor 6 and driving the electric W / P 5 when the boiling is detected. However, the water temperature sensor 6 is provided for the cooling water temperature (that is, the cooling water temperature detected during the stop control) detected when the electric W / P 5 is stopped (the flow rate is substantially “0”). It shows the cooling water temperature at the spot, and it cannot be said that it represents the cooling water temperature in all the cooling systems. Therefore, even if the temperature of the cooling water is actually partially high during the stop control, it is difficult to appropriately detect this. That is, it becomes difficult to detect the boiling of the cooling water.

  Therefore, in the present embodiment, the ECU 50 determines the possibility that the cooling water will boil (including the possibility that the cooling water has already boiled) before starting the stop control, thereby stopping the electric W / P5. It is determined whether or not the control should be started (start determination). In this case, when there is no possibility of boiling, the start of stop control is permitted, and when there is a possibility of boiling, the start of stop control is not permitted. Thereby, it becomes possible to avoid the boiling of the cooling water that may occur after the start of the stop control.

  Specifically, the ECU 50 drives the electric W / P 5 for a predetermined time when the engine 1 is started (before stop control), and performs stop control of the electric W / P 5 based on the coolant temperature detected at this time. It is determined whether or not to start (start determination). Specifically, the electric W / P 5 is driven so that the cooling water goes around the cooling water passage 7, and the start determination is performed by comparing the cooling water temperature detected at this time with a predetermined temperature. That is, the ECU 50 detects the cooling water temperature in all the cooling systems by supplying almost all the cooling water in the cooling water passage 7 to the water temperature sensor 6, and based on such cooling water temperature, The possibility that the cooling water will boil (including the possibility that the cooling water has already boiled) is determined. Thereby, the location where the water temperature is high other than the location where the water temperature sensor 6 is provided can be detected, and the possibility that the cooling water will boil can be accurately determined. In addition, for such a determination, the electric W / P5 is not driven more than necessary (that is, the driving of the electric W / P5 in the case where boiling does not occur can be effectively suppressed). Therefore, useless power consumption by the electric W / P5 can be suppressed.

  More specifically, when the detected coolant temperature is equal to or lower than a predetermined temperature, the ECU 50 permits the start of stop control because the possibility that the coolant will boil is very low. On the other hand, when the cooling water temperature is higher than the predetermined temperature, the ECU 50 does not allow the start of the stop control because the cooling water is likely to boil (the cooling water may already be boiling). . In this case, boiling of the cooling water is avoided by continuing to drive the electric W / P5.

  Thus, by performing the start determination according to the present embodiment, it is possible to appropriately boil the cooling water that can occur after the start of the stop control of the electric W / P5 while suppressing unnecessary power consumption by the electric W / P5. It can be avoided.

(Stop control end judgment)
Next, stop control end determination according to the present embodiment will be specifically described. In the present embodiment, the ECU 50 determines whether or not to stop the stop control based on the coolant temperature or the like (end determination) so that the stop control is ended when the engine 1 or the like is warmed up. I do.

  Specifically, the ECU 50 detects the coolant temperature detected during the stop control, the integrated air amount when the electric W / P5 is stopped (the integrated value of the intake air amount), and the integrated time when the electric W / P5 is stopped. Based on at least one of the following (hereinafter also referred to as “integrated stop time”), stop control end determination is performed. In this case, the water warmer at the location where the water temperature sensor 6 is provided can be determined from the cooling water temperature. Further, the amount of heat released to the cooling water in the engine main body or the head can be estimated from the accumulated air amount during the stop, and warm-up can be determined. Furthermore, by performing the end determination based on the total stop time, it is possible to appropriately stop the stop control even when the water temperature sensor 6 or the air flow meter (sensor for detecting the intake air amount) fails.

  By performing the above end determination, it is possible to appropriately determine warm-up, and it is possible to end the stop control at an appropriate timing.

(Cooling water temperature detection during stop control)
Next, the detection of the cooling water temperature performed during stop control will be described. In the present embodiment, the electric W / P5 is driven for a predetermined time when the integrated time (integrated stop time) during the stoppage of the electric W / P5 is longer than the predetermined time. And based on the cooling water temperature detected when performing such a drive, it is determined whether stop control is continued or stop control is complete | finished.

  The reason for performing the above control is as follows. When the accumulated stop time is long (for example, the accumulated stop time tends to be longer when the start of the stop control is at a very low temperature), the cooling water may boil during the stop control. That is, even if it is determined that the cooling water is unlikely to boil at the start of the stop control, if the accumulated stop time is long, the temperature of the cooling water partially rises during the stop control, Can boil. For example, when there is a place where the cooling water receives heat other than the place where the water temperature sensor 6 is provided, boiling of the cooling water may occur. Here, as described above, the cooling water temperature detected in a state where the electric W / P 5 is stopped does not represent the cooling water temperature in the entire cooling system, and therefore, the cooling water temperature is determined by this cooling water temperature. It can be said that it is difficult to detect boiling.

  Therefore, in the present embodiment, in order to avoid boiling that may occur during stop control, control similar to the control performed in the start determination of stop control described above is executed. Specifically, the ECU 50 drives the electric W / P 5 for a predetermined time when the accumulated stop time is longer than the predetermined time. Then, based on the coolant temperature detected at this time, whether stop control is continued (whether stop of electric W / P5 is continued), or whether stop control is ended (whether electric W / P5 is driven) ). Specifically, the ECU 50 performs the determination by driving the electric W / P 5 so that the cooling water goes around the cooling water passage 7 and comparing the cooling water temperature detected at this time with a predetermined temperature. . If the detected cooling water temperature is equal to or lower than the predetermined temperature, the possibility of boiling of the cooling water is quite low, so stop control is continued. On the other hand, when the cooling water temperature is higher than the predetermined temperature, there is a high possibility that the cooling water will boil (the cooling water may have already boiled). Boiling is avoided by driving P5. In this case, it is considered that the engine 1 and the like are warmed up. Therefore, it can be said that the stop control should be terminated.

  By performing the above control, it is possible to appropriately avoid the boiling of the cooling water that may occur during the stop control. Further, in the above-described control, the electric W / P5 is not driven more than necessary, so that useless power consumption by the electric W / P5 can be suppressed.

[Control processing of electric W / P]
Next, control processing of the electric W / P 5 according to the present embodiment will be described with reference to FIGS.

  FIG. 2 is a flowchart showing a control process of the electric W / P5. This process is executed when the engine 1 is started, and the above-described stop control start determination, stop control end determination, and cooling water temperature detection during stop control are executed. Note that the control process of the electric W / P 5 is executed by the ECU 50.

  First, in step S101, the ECU 50 sets a flag indicating the on / off of the stop control of the electric W / P5 (hereinafter referred to as an “electric W / P stop flag”) to be off. This is for driving the electric W / P 5 in the process of the following step S102. Then, the process proceeds to step S102.

  In step S102, the ECU 50 drives the electric W / P5 for a predetermined time, and stores the maximum value of the coolant temperature detected at this time (hereinafter referred to as “thw maximum value”). Specifically, the ECU 50 drives the electric W / P 5 only for the time required for the cooling water to go around the cooling water passage 7 once. And ECU50 calculates | requires thw maximum value from the cooling water temperature acquired from the water temperature sensor 6 when performing such a drive, and memorize | stores thw maximum value. When the above process ends, the process proceeds to step S103.

  In step S103, the ECU 50 determines whether or not the maximum thw value obtained in step S102 is equal to or lower than a predetermined temperature THW1. Here, it is determined whether or not boiling of the cooling water is likely to occur. That is, it is determined whether to start the stop control of the electric W / P 5 (start determination). The predetermined temperature THW1 is set to “60 ° C.”, for example.

  When the thw maximum value is equal to or lower than the predetermined temperature THW1 (step S103; Yes), the process proceeds to step S103. In this case, it can be said that the possibility that the cooling water boils is quite low. Therefore, in step S104, the ECU 50 starts the stop control by switching the electric W / P stop flag from off to on. Then, the process proceeds to step S105. On the other hand, when the thw maximum value is higher than the predetermined temperature THW1 (step S103; No), the process exits the flow. In this case, it can be said that the cooling water is likely to boil (the cooling water may have already boiled). Therefore, ECU 50 keeps the electric W / P stop flag off and does not allow the start of stop control. In this case, boiling of the cooling water is avoided by continuing to drive the electric W / P5.

  In step S105, the ECU 50 determines whether or not the coolant temperature thw during the stop control is higher than a predetermined temperature THW2. Here, it is determined whether or not the engine 1 or the like has been warmed up. That is, it is determined whether or not the stop control should be ended (end determination). As the cooling water temperature thw, an average value or a maximum value of the cooling water temperature detected during the stop control can be used. The predetermined temperature THW2 is set to “70 ° C.”, for example. Thus, by making a determination based on the cooling water temperature thw, it is possible to determine the water warmer at the location where the water temperature sensor 6 is provided.

  When the cooling water temperature thw is higher than the predetermined temperature THW2 (step S105; Yes), the process proceeds to step S109. In this case, it can be said that the engine 1 and the like are warmed up and the stop control should be terminated. Therefore, in step S109, the ECU 50 ends the stop control by switching the electric W / P stop flag from on to off. Then, the process exits the flow.

  On the other hand, when the coolant temperature thw is equal to or lower than the predetermined temperature THW2 (step S105; No), the process proceeds to step S106. In this case, since it could not be determined that the engine 1 or the like is warmed up from the coolant temperature, the engine 1 or the like is based on other parameters (integrated air amount, integrated stop time) in the subsequent processing. It is determined whether or not is warming up.

  In step S106, the ECU 50 has an accumulated air amount (hereinafter, referred to as “integrated Ga”) when the electric W / P5 is stopped larger than a predetermined value (hereinafter referred to as “completion calculation GA1”). It is determined whether or not. Here again, it is determined whether or not the engine 1 has been warmed up. That is, it is determined whether or not the stop control should be ended (end determination). The integrated Ga can be obtained based on the intake air amount detected by the air flow meter. Further, the end determination calculation GA1 can be obtained from a map defined by the coolant temperature at the start of the stop control of the electric W / P5 (hereinafter referred to as “stop start time thw”).

  FIG. 3 shows an example of a map representing the relationship between the stop start time thw and the end determination calculation GA1. As shown in the figure, it can be understood that the end determination calculation GA1 decreases as the stop start time thw increases. This is because the engine 1 and the like tend to warm up earlier as the stop start thw becomes higher.

  Returning to FIG. 2, the process of step S106 will be described. As described above, by making a determination based on the integrated Ga during the stop control, it is possible to estimate the amount of heat released to the cooling water in the engine body or the head, and it is possible to appropriately determine warm-up.

  When the integrated Ga is larger than the end determination calculation GA1 (step S106; Yes), the process proceeds to step S109. In this case, it can be said that the engine 1 and the like are warmed up and the stop control should be terminated. Therefore, in step S109, the ECU 50 ends the stop control by switching the electric W / P stop flag from on to off. Then, the process exits the flow.

  On the other hand, when the integrated Ga is equal to or less than the end determination calculation GA1 (step S106; No), the process proceeds to step S107. In this case, since it could not be determined from the integrated Ga that the engine 1 or the like has been warmed up, in the subsequent processing, the engine 1 or the like has been warmed up based on other parameters (integrated stop time). It is determined whether or not there is.

  In step S107, the ECU 50 determines whether or not the integrated time (integrated stop time) during the stoppage of the electric W / P5 is longer than a predetermined time (hereinafter referred to as “end determination integrated time TIME1”). Here again, it is determined whether or not the engine 1 has been warmed up. That is, it is determined whether or not the stop control should be ended (end determination). The end determination integration time TIME1 can be obtained from a map defined by the coolant temperature (stop start time thw) at the start of stop control of the electric W / P5.

  FIG. 4 shows an example of a map representing the relationship between the stop start time thw and the end determination integrated time TIME1. As shown in the figure, it can be seen that the end determination integrated time TIME1 decreases as the stop start time thw increases. This is because the engine 1 and the like tend to warm up earlier as the stop start thw becomes higher.

  Returning to FIG. 2, the process of step S107 will be described. As described above, the end determination is performed based on the total stop time, so that the stop control can be appropriately ended even when the water temperature sensor 6 or the air flow meter fails.

  When the integration stop time is longer than the end determination integration time TIME1 (step S107; Yes), the process proceeds to step S109. In this case, it can be said that the engine 1 and the like are warmed up and the stop control should be terminated. Therefore, in step S109, the ECU 50 ends the stop control by switching the electric W / P stop flag from on to off. Then, the process exits the flow.

  On the other hand, when the integration stop time is less than or equal to the end determination integration time TIME1 (step S107; No), the process proceeds to step S108. In this case, it is considered that the possibility that the engine 1 or the like is warmed up is low.

  In step S108, the ECU 50 determines whether or not the integration stop time is longer than the predetermined time TIME2. The determination in step S108 is performed to determine whether or not it is a situation in which it is necessary to determine whether or not the cooling water may boil. That is, it is determined whether or not to determine whether or not the cooling water may boil based on the cooling water temperature when the electric W / P 5 is driven for a predetermined time as described above. The predetermined time TIME2 is set to “200 sec”, for example.

  When the integration stop time is equal to or shorter than the predetermined time TIME2 (step S108; Yes), the process exits the flow. In this case, since the accumulated stop time is relatively short, it is considered that the possibility that the cooling water will boil is considerably low, and it can be said that it is not necessary to determine whether or not the cooling water may boil. . In this case, the engine 1 is not warmed up. Therefore, ECU 50 keeps the electric W / P stop flag off and continues the stop control.

  On the other hand, when the integration stop time is longer than the predetermined time TIME2 (step S108; No), the process proceeds to step S110. In this case, since the integration stop time is relatively long, it can be said that it is in a situation where it should be determined whether or not the cooling water may boil. Therefore, in step S110, the ECU 50 drives the electric W / P5 for a predetermined time. Specifically, the ECU 50 drives the electric W / P 5 only for the time required for the cooling water to go around the cooling water passage 7 once. This is for acquiring the cooling water temperature in all the cooling systems in order to appropriately determine the possibility that the cooling water will boil. When the above process ends, the process returns to step S105.

  In step S105, the ECU 50 determines whether or not the coolant temperature thw acquired during the control in step S110 is higher than a predetermined temperature THW2. Here, it is determined whether or not the cooling water may boil. When the cooling water temperature thw is higher than the predetermined temperature THW2 (step S105; Yes), the cooling water may have boiled (the cooling water may have already boiled), so in step S109, The ECU 50 switches the electric W / P stop flag from on to off. That is, stop control is complete | finished and electric W / P5 is driven. Thereby, boiling of cooling water can be avoided. In this case, it is considered that the engine 1 and the like are warmed up. On the other hand, when the cooling water temperature thw is equal to or lower than the predetermined temperature THW2 (step S105; No), since the possibility that the cooling water is boiling is quite low, the processing after step S106 is performed again. That is, it is determined again whether or not the engine 1 or the like has been warmed up (end determination as to whether or not to stop the control).

  According to the processing described above, it is possible to appropriately avoid the boiling of the cooling water that can occur after the start of the stop control of the electric W / P5 and the boiling of the cooling water that can occur during the stop control of the electric W / P5. it can. In the above-described processing, the electric W / P5 is not driven more than necessary (that is, the driving of the electric W / P5 in the case where boiling does not occur can be effectively suppressed). Wasteful power consumption due to the electric W / P5 can be suppressed. Furthermore, the warm-up of the engine 1 or the like can be appropriately determined, and the stop control of the electric W / P 5 can be terminated at an appropriate timing.

  In the above description, when the coolant temperature thw is higher than the predetermined temperature THW2, or when the integrated Ga is larger than the end determination calculation GA1, or when the integrated stop time is longer than the end determination integrated time TIME1, Although an example of terminating the control has been shown, the present invention is not limited to this. In another example, when the coolant temperature thw is higher than the predetermined temperature THW2, and / or when the integrated Ga is larger than the end determination calculation GA1, and / or the integrated stop time is longer than the end determination integrated time TIME1. In this case, the stop control can be terminated.

[Modification]
Here, a cooling system according to a modification will be described with reference to FIG. FIG. 5 is a diagram illustrating a schematic configuration of a cooling system 101 according to a modification. In addition, about the component same as the cooling system 100 (refer FIG. 1) mentioned above, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  The cooling system 101 differs from the cooling system 100 in that the exhaust heat recovery device 20 is provided on the cooling water passage 7a. The exhaust heat recovery unit 20 is provided on an exhaust passage (not shown) through which exhaust gas from the engine 1 flows, and cooling water flows through the exhaust heat recovery unit 20. In this case, the exhaust heat recovery device 20 performs heat exchange between the cooling water and the exhaust gas.

  Also in the cooling system 101 as described above, the ECU 50 can execute the same control as the control for the electric W / P 5 described above. In this case, the temperature of the cooling water tends to be partially high at the location where the exhaust heat recovery device 20 is provided (that is, the cooling water may boil due to the exhaust heat recovery device 20). By performing the above-described stop control start determination and the like, while suppressing wasteful power consumption by the electric W / P5, the cooling water is appropriately prevented from boiling and the electric W / P5 is stopped. It becomes possible.

It is a figure which shows schematic structure of the cooling system which concerns on this embodiment. It is a flowchart which shows the control process of electric W / P. An example of the map showing the relationship between the stop start time thw and the end determination calculation GA1 is shown. An example of the map showing the relationship between the stop start time thw and the end determination integrated time TIME1 is shown. It is a figure which shows schematic structure of the cooling system which concerns on a modification.

Explanation of symbols

1 engine (internal combustion engine)
3 Radiator 4 Thermostat 5 Electric water pump (electric W / P)
6 Water temperature sensor 7 Cooling water passage 20 Exhaust heat recovery unit 50 ECU
100, 101 Cooling system

Claims (5)

In a control device for an electric water pump that controls an electric water pump that circulates cooling water in an internal combustion engine,
Electric water pump drive means for driving the electric water pump for a predetermined time at the start of the internal combustion engine;
Stop determining that the control to stop the electric water pump should be started when the temperature of the cooling water when the electric water pump is being driven by the electric water pump driving means is equal to or lower than a predetermined temperature Control start determination means;
Electric water pump stop means for executing control for stopping the electric water pump when the stop control start determining means determines that the control for stopping the electric water pump should be started. Electric water pump control device.   The electric motor according to claim 1, wherein the predetermined time for the electric water pump driving means to drive the electric water pump substantially corresponds to a time required for the cooling water to go around the cooling water passage. Water pump control device.   When the electric water pump is stopped by the electric water pump stop means, at least one of the temperature of the cooling water, the integrated air amount during the stop of the electric water pump, and the stop time of the electric water pump 3. The electric water pump control device according to claim 1, further comprising: a stop control end determination unit configured to determine whether to stop the control for stopping the electric water pump based on the control.   The stop control end determination means, when performing the determination based on the integrated air amount when the electric water pump is stopped or the stop time of the electric water pump, the cooling water at the start of the stop of the electric water pump The control device for an electric water pump according to claim 3, wherein the determination is performed using a determination value according to temperature.   When the stop time of the electric water pump is longer than a predetermined time, the electric water pump is driven for the predetermined time, and the temperature of the cooling water when the electric water pump is driven is equal to or lower than a predetermined temperature. 5. The electric water pump control device according to claim 1, further comprising means for continuously executing control for stopping the electric water pump.

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