JP2008121656A - Cooling system of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent overheating of an internal combustion engine when an electric water pump fails. <P>SOLUTION: A cooling system (1) cools the internal combustion engine in a vehicle equipped with the internal combustion engine (11) and an electric motor (40). The cooling system comprises a circulation flow path (21) in which a coolant for cooling the internal combustion engine flows, the electric water pump (22) for circulating the coolant, a temperature measurement means (26) for measuring the temperature of the coolant, a failure determination means (30) for determining whether or not the electric water pump fails, and a shift control means (30) for shifting the operation mode of the vehicle to a fail safe mode if the measured temperature is higher than a first predetermined temperature when the electric pump is determined to fail. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a cooling device for an internal combustion engine including an electric water pump in a vehicle such as an automobile.

  In this type of cooling device, when the electric water pump fails, there arises a problem that, for example, the internal combustion engine is overheated.

  The cooling control device described in Patent Literature 1 calculates a power value of the electric motor based on the current and voltage of the electric motor of the electric water pump, and determines a failure of the electric water pump based on the power value. When a failure occurs, a warning lamp is turned on to give a warning, and the operation shifts to a fail safe mode to suppress overheating, thereby enriching the fuel injection amount of the internal combustion engine via the fuel injection control device.

  In the cooling device described in Patent Document 2, when the coolant temperature after passing through the internal combustion engine is equal to or higher than a predetermined reference temperature, the fuel supply amount is increased by the fuel supply device, and the blower provided in the coolant circulation path is driven. The internal combustion engine is prevented from overheating by the electronic throttle fully closing process, the ignition timing control by the ignition device, and the like.

  The cooling device described in Patent Document 3 includes a liquid circulation pump (mechanical pump) connected to the internal combustion engine by a drive belt in addition to the electric water pump. When the electric water pump breaks down, general travel is possible with the mechanical pump. Further, when the water temperature of the internal combustion engine is higher than a predetermined temperature, the radiator fan is operated.

JP 2000-303839 A JP 2006-105105 A JP 2006-161806 A

  However, the techniques described in Patent Documents 1 and 2 have a technical problem that the internal combustion engine does not stop and generates heat, which may cause overheating.

  Moreover, in the technique of patent document 2, it transfers to the fail safe mode based only on the temperature of a cooling medium. If the electric water pump fails, the cooling medium does not circulate and the response of the temperature sensor is delayed.Therefore, after overheating, the system switches to fail-safe mode, or actually enters into fail-safe mode without overheating. There is a technical problem that it will migrate.

  In the technique described in Patent Document 3, it is necessary to secure a space necessary for installing the mechanical pump and the piping associated therewith, and there is a technical problem that the degree of freedom of the layout of the vehicle is hindered.

  The present invention has been made in view of the above-mentioned problems, for example, and it is an object to provide a cooling device that can prevent an internal combustion engine from overheating when an electric water pump fails. To do.

  In order to solve the above problems, a first cooling device of the present invention is a cooling device that cools the internal combustion engine in a vehicle including an internal combustion engine and an electric motor, in which a cooling medium that cools the internal combustion engine flows. A flow path, an electric water pump for circulating the cooling medium, a temperature measuring means for measuring the temperature of the cooling medium, a failure determination means for determining whether or not the electric water pump has failed, and the electric water And transition control means for shifting the operation mode of the vehicle to the fail-safe mode on condition that the measured temperature is higher than a first predetermined temperature when it is determined that the pump is malfunctioning.

  According to the first cooling device of the present invention, a cooling medium such as LLC (Long Life Coolant) flows through the circulation flow path to cool the internal combustion engine. The electric water pump forcibly circulates the cooling medium in the circulation flow path to increase the cooling efficiency. For example, a temperature measuring means that is a temperature sensor measures the temperature of the cooling medium. For example, a failure determination unit that is an ECU (Electronic Control Unit) determines whether or not the electric water pump has failed. Note that the “electric water pump failure” according to the present invention refers to a failure in which the motor of the electric water pump stops, such as a lock failure, and the circulating flow rate of the cooling medium becomes zero.

  When it is determined that the electric water pump is malfunctioning, for example, the transition control means that is an ECU sets the vehicle operation mode to the fail-safe mode on condition that the measured temperature of the cooling medium is higher than the first predetermined value. Transition. Here, the “fail safe mode” according to the present invention means that the vehicle is driven only by the electric motor without using the driving force of the internal combustion engine, or the number of cylinders is reduced, for example, to drastically reduce the load of the internal combustion engine. This is an operation mode for causing the internal combustion engine and the electric motor to perform retreat travel safely.

  When the electric water pump is out of order, the circulating flow rate of the cooling medium is zero, so that there is no heat transfer due to the cooling medium circulation, that is, forced convection, and heat is transferred mainly by heat conduction in the cooling medium. Therefore, even if the temperature of the cooling medium near the combustion chamber wall of the internal combustion engine is high, the temperature of the cooling medium measured by the temperature measuring means shows a low value. Alternatively, even if the temperature of the cooling medium near the combustion chamber wall is low, the measured temperature of the cooling medium shows a high value. That is, the responsiveness of the measured temperature of the cooling medium is deteriorated.

  Therefore, in the present invention, the first predetermined temperature is set to fail when the electric water pump is not out of order, that is, in the normal mode or in the normal travel mode, considering that the response of the measured temperature of the cooling medium is deteriorated. If it is set to a temperature lower than the temperature at which it enters the safe mode (for example, 105 degrees Celsius or 115 degrees Celsius), for example, if it is set to 80 degrees Celsius or 90 degrees Celsius, the internal combustion engine will overheat if the electric water pump fails. This can be surely prevented.

  On the other hand, the failure determination means may determine that the electric water pump has failed due to, for example, a temporary stop of the electric water pump or a failure of a sensor or failure determination means that detects the operating state of the electric water pump. There is. In this case, it is a so-called misjudgment, and it is disadvantageous or inconvenient for the driver, the mechanic, etc., if the electric water pump has failed and immediately shifts to the fail-safe mode. In other words, even if it is determined that the electric water pump is out of order, if the temperature of the cooling medium is ignored and the state immediately shifts to the fail-safe mode, it cannot be said that it is an appropriate response if the presence of erroneous determination is taken into consideration. . In the case of a misjudgment, it is forced to go to maintenance or repair after stopping normal driving even though it has not actually failed or is not actually hot (ie, no overheating has occurred) It is done.

  Therefore, in consideration of the possibility of erroneous determination, the first predetermined temperature may be set to an upper limit temperature at which temperature control is possible, for example, by controlling the flow rate of the cooling medium using a thermostat. If the determination is incorrect, the electric water pump is operating normally, so that there is a circulation of the cooling medium, and the temperature can be controlled by a thermostat. Further, even when the electric water pump is actually broken down, the transition to the fail-safe mode is performed at a temperature lower than normal, so that there is no problem with fail-safe.

  If the first predetermined temperature is set in this way, overheating of the internal combustion engine can be prevented when the electric water pump fails. Furthermore, it is possible to prevent transition to the fail-safe mode after overheating, and it is possible to prevent transition to the fail-safe mode in the case of an erroneous determination, that is, in a situation where the overheating does not actually occur.

  As a result, according to the first cooling device of the present invention, it is possible to prevent the internal combustion engine from overheating when the electric water pump fails.

  In one aspect of the first cooling device of the present invention, the failure determination means includes monitoring means for monitoring an operating state of the electric water pump, and the electric water pump fails based on the monitored operating state. It is determined whether or not.

  According to this aspect, the monitoring means, which is a sensor, for example, monitors the operating state of the electric water pump. Specifically, the monitoring means monitors, for example, the number of rotations of the electric water pump as the operation state to be monitored. In other words, the rotational speed is counted or detected. Alternatively, for example, the current value of the electric water pump is monitored as the operation state to be monitored. In other words, the current value is measured or detected.

  Here, the “operating state” according to the present invention is one in which the operating state is expressed in a form that can be monitored or manifested, and is typically expressed by some physical quantity or parameter related to the operating state. ing. “Monitoring” according to the present invention typically means “detection”, “measurement”, “measurement”, “monitoring” of some physical quantity or parameter indicating such an operating state, directly or indirectly. Means to equal. Furthermore, a change or difference (how to change, the degree of difference) of any physical quantity or parameter indicating such an operating state with respect to a standard value or a reference value is directly or indirectly detected, measured, It may include “measurement”, “monitoring”, and the like.

  The failure determination means determines whether or not the electric water pump has failed based on the monitored operating state. Here, “based on the operating state” according to the present invention typically means based on some physical quantity or parameter indicating the monitored operating state. Specifically, if the monitored operation state is the rotation speed of the electric water pump, the failure determination means determines whether or not the electric water pump has failed based on the rotation speed. Alternatively, if the monitored operation state is a current value of the electric water pump, it is determined based on the current value whether or not the electric water pump has failed.

  More specifically, for example, the magnitude relationship between a physical quantity or parameter indicating the monitored operation state and a predetermined threshold is determined to determine whether or not the electric water pump has failed. This makes it easy to determine whether or not a failure has occurred, which is very advantageous in practice.

  In another aspect of the first cooling device of the present invention, the transition control means determines whether the measured temperature is higher than the first predetermined temperature when it is determined that the electric water pump has failed. Temperature determining means for determining whether the measured temperature is higher than the first predetermined temperature, the operation mode is shifted to the fail-safe mode, and the measured temperature is 1 When it is determined that the temperature is lower than the predetermined temperature, the operation mode is not shifted to the fail-safe mode.

  According to this aspect, the temperature determination unit determines whether or not the temperature of the coolant measured by the temperature measurement unit is higher than the first predetermined temperature when it is determined that the electric water pump has failed. To do. The transition control means shifts the operation mode to the fail-safe mode when it is determined that the measured temperature is higher than the first predetermined temperature. Thereby, it can transfer to fail safe mode promptly and it can prevent that an internal combustion engine overheats.

  Further, when it is determined that the measured temperature is lower than the first predetermined temperature, the transition control means does not shift the operation mode to the fail-safe mode, that is, remains in the normal travel mode. In other words, if the measured temperature is equal to or lower than the first predetermined temperature, the transition to the failsafe mode is prohibited. Thereby, since it can drive | work using an internal combustion engine until the temperature of a cooling medium turns into 1st predetermined temperature, the time or driving | running | working distance until it makes an operation mode transfer to fail safe mode can be lengthened. .

  It should be noted that the determination relating to the temperature level by the temperature determination means may be made at all times, including the case where it is determined that the electric water pump has not failed, or regardless of the determination of such failure. And when it determines with the electric water pump having failed, based on the result in the time of determination, it may just be to transfer to fail safe mode.

  In another aspect of the first cooling device of the present invention, the transition control means determines that the measured temperature is higher than the first predetermined temperature when it is determined that the electric water pump has not failed. The operation mode is shifted to the failsafe mode on condition that the temperature is higher than the second predetermined temperature.

  According to this aspect, the second predetermined temperature is set as a temperature at which the electric water pump is not broken, that is, at the time of normal operation or normal travel mode, for example, 105 degrees Celsius or 115 degrees Celsius. . As a result, it is possible to reliably prevent the internal combustion engine from overheating at normal times when the electric water pump is not broken, shifting to the fail-safe mode after overheating, and further shifting to the fail-safe mode without overheating.

  In another aspect of the first cooling device of the present invention, the vehicle further includes an electric throttle for adjusting a supply amount of air to the internal combustion engine, and the vehicle is driven by the electric motor in the fail-safe mode. And the transition control means determines that the measured temperature is lower than the first predetermined temperature and lower than the first predetermined temperature when it is determined that the electric water pump has failed. On the condition that the temperature is higher than a predetermined temperature, the operation mode is shifted to a limited travel mode in which the opening degree of the electric throttle is limited.

  According to this aspect, when it is determined that the electric water pump has failed, the transition control means has a temperature of the cooling medium measured by the temperature measurement means that is lower than the first predetermined temperature and the third predetermined temperature. On the condition that the temperature is higher than the temperature, that is, on the condition that the temperature range is between the third predetermined temperature and the first predetermined temperature, the operation mode is shifted to the limited travel mode that limits the opening of the electric throttle. In other words, the amount of air supplied to the internal combustion engine is limited by the electric throttle. Specifically, the temperature increase of the internal combustion engine is suppressed by reducing the amount of air supplied to the internal combustion engine and lowering the rotational speed of the internal combustion engine. Such a “restricted driving mode” can be handled as one of the fail-safe modes in a broad sense. However, here, the “restricted travel mode” is a “fail safe mode” (in other words, “narrow fail safe mode”) that is not shifted unless the first predetermined temperature is reached when the electric water pump fails as described above. It will be treated as another operation mode.

  The third predetermined temperature, which is the temperature for shifting to the limited travel mode, is lower than the first predetermined temperature, which is the temperature for shifting to the failsafe mode. For example, the third predetermined temperature is set to a temperature about 10 degrees lower than the first predetermined temperature, such as 70 degrees Celsius or 80 degrees Celsius. Therefore, although the normal travel mode is not reached until the temperature of the cooling medium reaches the first predetermined temperature, the internal combustion engine can be used to travel in a state that is approximately normal or close to normal travel. Further, since the limited travel is performed, the temperature increase of the internal combustion engine is suppressed, and the time or travel distance until the operation mode is shifted to the fail safe mode can be further increased. At this time, unless the mode is shifted to the fail-safe mode, the return from the restricted travel mode to the normal travel mode is relatively easily performed according to the temperature drop.

  Note that the third predetermined temperature is set in consideration of the deterioration of the responsiveness of the measured temperature of the cooling medium.

  In addition, in this aspect, when it is determined that the electric water pump has not failed, the transition control unit is configured to provide a fourth predetermined temperature (e.g., a temperature that is higher than the third predetermined temperature). The driving mode may be shifted to the limited driving mode on condition that the driving temperature is higher than 95 degrees Celsius or 105 degrees Celsius). With this configuration, the shift to the limited travel mode that suppresses the temperature increase or contributes to the temperature decrease functions extremely effectively as a measure for avoiding overheating during normal travel. Further, even when the mode is shifted to the limited travel mode, the operation mode is shifted to the fail-safe mode on condition that the temperature is higher than the second predetermined temperature (for example, 105 degrees Celsius or 115 degrees Celsius). May be.

  In another aspect of the first cooling device of the present invention, the storage device further includes storage means having a plurality of ignition delay maps, and the transition control means, when it is determined that the electric water pump has failed, The ignition retard map is switched.

  According to this aspect, the storage means, which is a memory, for example, has a plurality of ignition retardation maps corresponding to the traveling state of the vehicle. Here, the ignition retard map is a map that determines the retard amount of the ignition timing in accordance with, for example, the temperature of the cooling medium or the temperature of the internal combustion engine. Such a map may be composed of data acquired through experiments, simulations, and the like. Specifically, for example, such a map is obtained by acquiring data on the degree of rise or fall of the temperature of the cooling medium in various retardation amounts and specifying the optimum retardation amount based on the data or the like. May be configured.

  When it is determined that the electric water pump has failed, the transition control means switches the ignition retard map. Specifically, when it is determined that there is a failure, since there is no circulation of the cooling medium, considering that the responsiveness of the temperature of the cooling medium measured by the temperature measuring means deteriorates, the low temperature For example, switching to an ignition delay map that retards the ignition timing from 60 degrees Celsius to suppress the temperature rise of the internal combustion engine. Thereby, when an electric water pump fails, the distance or time which can be traveled using an internal combustion engine can be lengthened. Such an operation mode of “switching the ignition delay angle” can be treated as one of fail-safe modes in a broad sense. However, here, the operation mode of “switching the ignition delay angle” is treated as an operation mode different from the “fail-safe mode” as described above.

  In this aspect, the fail-safe mode is a mode in which the vehicle is driven by the electric motor, and the transition control means determines that the measured temperature is when the electric water pump is determined to have failed. The operation mode is set on condition that it is higher than a third predetermined temperature lower than the first predetermined temperature and lower than the first predetermined temperature (a temperature lower than the first predetermined temperature, such as 70 degrees Celsius or 80 degrees Celsius). You may comprise so that it may transfer to the operation mode which switches this ignition retard. Alternatively, the fail-safe mode is a mode in which the vehicle is driven by the electric motor, and the transition control means determines that the measured temperature is determined when the electric water pump has failed. The operation mode is ignited on the condition that it is higher than a fifth predetermined temperature (a temperature lower than the third predetermined temperature, such as 60 degrees Celsius or 70 degrees Celsius) lower than the third predetermined temperature and lower than the third predetermined temperature. You may comprise so that it may make it transfer to the operation mode which switches retardation. If comprised in this way, even if the temperature of a cooling medium rises, until it reaches the 1st predetermined temperature, while suppressing the temperature rise using the ignition delay angle (although it does not go to normal driving mode) or It is possible to travel in a state that is generally normal or close to normal traveling while promoting a temperature drop. At this time, unless the mode is shifted to the fail-safe mode, switching the ignition timing to the normal timing is relatively easily performed according to the temperature drop.

  In addition, in this aspect, when it is determined that the electric water pump has not failed, the transition control unit is configured to provide a fourth predetermined temperature (e.g., a temperature that is higher than the third predetermined temperature). The operation mode may be shifted to the operation mode by switching the ignition delay angle on the condition that the temperature is higher than 105 degrees Celsius or 115 degrees Celsius). Alternatively, the transition control means, when it is determined that the electric water pump has not failed, a sixth predetermined temperature (for example, 80 degrees Celsius or Celsius) in which the measured temperature is higher than the fifth predetermined temperature. The operation mode may be shifted to the operation mode with the ignition delay being switched on condition that the angle is higher than 90 degrees. If comprised in this way, the transition to the operation mode by switching the ignition delay angle that suppresses the temperature rise or contributes to the temperature drop functions extremely effectively as a measure for avoiding overheating during normal running. Further, even when the ignition delay is switched as described above, the operation mode is shifted to the fail-safe mode on condition that the temperature is higher than the second predetermined temperature (for example, 105 degrees Celsius or 115 degrees Celsius). Also good.

  In another aspect of the first cooling device of the present invention, the electric cooling fan further includes an electric fan that cools the internal combustion engine, and the transition control unit is configured to operate the electric motor when it is determined that the electric water pump has failed. Turn on the fan.

  According to this aspect, for example, the electric fan, which is a radiator fan, is provided between the internal combustion engine and the radiator provided in the circulation flow path. Here, the electric fan refers to a fan that can be operated as needed independently of the operating state of the internal combustion engine such as the rotational speed. When it is determined that the electric water pump has failed, the transition control means operates the electric fan regardless of the temperature of the cooling medium, and actively cools the internal combustion engine, thereby increasing the temperature of the internal combustion engine. Suppress. Thereby, when an electric water pump fails, the distance or time which can be traveled using an internal combustion engine can be lengthened. Such an operation mode of “operating the electric fan” can be handled as one of fail-safe modes in a broad sense. However, here, the operation mode of “operating the electric fan” is treated as an operation mode different from the “fail-safe mode” as described above.

  In this aspect, the fail-safe mode is a mode in which the vehicle is driven by the electric motor, and the transition control means determines that the electric water pump is out of order, regardless of the temperature. You may comprise so that an operation mode may be changed to the operation mode which operates this electric fan. If comprised in this way, even if the temperature of a cooling medium will rise, until it will become 1st predetermined temperature, using an electric fan (though it does not go to normal driving mode), suppressing temperature rise or temperature It is possible to travel in a state that is generally normal or close to normal traveling while promoting descent. At this time, unless the mode is shifted to the fail-safe mode, switching the electric fan to the normal operation state is relatively easily performed according to the temperature drop.

  In addition, in this aspect, when it is determined that the electric water pump is not malfunctioning, the transition control unit has a seventh predetermined temperature (e.g., higher than the third predetermined temperature). You may comprise so that the said operation mode may be changed to the operation mode which operates the said electric fan on condition that it is higher than 90 degree | times Celsius or 100 degree Celsius). If comprised in this way, the transition to the operation mode which operates the electric fan which suppresses a temperature rise or contributes to a temperature fall will function very effectively as a countermeasure for avoiding the overheating at the time of normal driving | running | working.

  In order to solve the above problems, a second cooling device of the present invention is a cooling device that cools the internal combustion engine in a vehicle including an internal combustion engine and an electric motor, and a circulation through which a cooling medium that cools the internal combustion engine flows. A flow path, an electric water pump for circulating the cooling medium, a temperature measuring means for measuring the temperature of the cooling medium, an air amount detecting means for detecting the amount of air taken into the internal combustion engine, and the electric water pump A failure determination means for determining whether or not the electric water pump has failed, and the electric water pump measured when the electric water pump is determined to be defective when it is determined that the electric water pump has failed. On the condition that the difference between the temperature of the cooling medium and the temperature of the cooling medium measured when the accumulated value of the detected air amount reaches the predetermined accumulated value is larger than the predetermined temperature difference. And a transition control means to shift the operation mode of the vehicle to the fail-safe mode.

  According to the second cooling device of the present invention, the air amount detection means detects the amount of air taken into the internal combustion engine. Specifically, for example, the air amount may be directly detected by an air flow meter, or the air amount is indirectly detected by detecting the throttle opening, the pressure in the intake passage, and the rotational speed of the internal combustion engine. It may be detected. Here, the “air amount” may be an air amount per unit time, or may be an accumulated air amount from the measurement reference time or the measurement start time.

  When it is determined that the electric water pump has failed, the transition control means is configured to accumulate the temperature of the cooling medium measured when it is determined that the electric water pump has failed and the detected air amount. The operation mode of the vehicle is shifted to the fail safe mode on condition that the difference from the temperature of the cooling medium measured when the value reaches the predetermined cumulative value is larger than the predetermined temperature difference.

  Here, the “predetermined temperature difference” according to the present invention refers to a reference value for determining whether or not to shift the operation mode to the fail-safe mode, that is, the temperature of the soot that is seen when the electric water pump has not failed. It is a reference value or threshold value for distinguishing the change from the soot temperature change seen when the electric water pump is out of order. This may be a fixed value, or may be variable depending on the temperature of the cooling medium measured when it is determined that the electric water pump has failed, for example. Specifically, for example, when the temperature of the cooling medium measured at the time of determination is 70 degrees Celsius, the predetermined temperature difference may be set to 5 degrees Celsius or the like.

  Such a predetermined temperature difference is measured, for example, by experimentally measuring the temperature and temperature change of the cooling medium during normal operation of the electric water pump and the temperature and temperature change of the cooling medium when stopped (that is, at the time of failure). What is necessary is just to set as a value of the temperature change which does not occur in normal operation. The “difference” or “temperature difference” is not limited to a direct temperature difference, and may be, for example, an index value difference that indirectly indicates temperature, and is represented by a percentage, a ratio, or a ratio. It may be a difference. In other words, it may mean a temperature difference in a broad sense.

  According to the research of the present inventor, generally, the temperature of the cooling medium at the time of failure of the electric water pump is dominated by the temperature of the combustion chamber wall and the valve seat, and the temperature of the combustion chamber wall and the valve seat is the internal combustion engine. It has been found that the degree of temperature change varies depending on the amount of air sucked into the air. Therefore, in the present invention, when it is determined that the electric water pump has failed, the period from the measurement of the temperature of the cooling medium to the next measurement of the temperature of the cooling medium is determined by the amount of air. For example, it is possible to prevent the temperature of the cooling medium from being measured after the internal combustion engine is overheated.

  Here, “when it is determined that the electric water pump has failed” is not limited to the time when it is determined that the electric water pump has failed, but, for example, the time spent for determination by the failure determination means In consideration of the above, it may be the time when the electric water pump actually fails a little later in time than the determined time, or the time delay until the temperature of the internal combustion engine is reflected in the cooling medium is considered. Then, a predetermined minute time may be passed from the determined time.

  In addition, “when the predetermined cumulative value is reached” means when the cumulative value of air becomes greater than or equal to the predetermined cumulative value, or when it exceeds the predetermined cumulative value or exceeds the predetermined cumulative value. The “predetermined cumulative value” according to the present invention refers to the time from when the temperature of the cooling medium is measured to when the temperature of the cooling medium is measured when it is determined that the electric water pump has failed. This parameter determines the period. Such a predetermined cumulative value is obtained, for example, by experimentally measuring the relationship between the intake air amount and the temperature change of the cooling medium when the electric water pump is stopped (that is, when a failure occurs). The amount of air may exceed the range.

  Further, the “cumulative value of air amount” is a cumulative value of the amount of air taken into the internal combustion engine after it is determined that the electric water pump has failed. The reference time or the start of measurement when obtaining the accumulated value is not limited to the time point when it is determined that the electric water pump is broken, but may be, for example, a time point slightly later than the determined time point. However, it may be a time when a predetermined minute time is passed from the determined time. When the air amount detecting means detects the air amount per unit time, the accumulated value may be obtained by integrating the detected air amount. Alternatively, when the air amount detecting means detects the integrated air amount, the detected air amount may be set as a cumulative value.

  In the second cooling device of the present invention, the operation mode is shifted to the fail safe mode based on the temperature difference of the coolant temperature, that is, the degree of temperature change. As a result, even if the temperature of the coolant measured when it is determined that the electric water pump is malfunctioning is low (for example, 60 degrees Celsius), the operation mode immediately depends on the degree of temperature change. Can be shifted to the fail-safe mode to reliably prevent the internal combustion engine from overheating.

  On the other hand, when the determination in the failure determination means is a so-called erroneous determination, the detected temperature difference of the cooling medium is small or the temperature of the internal combustion engine decreases. Therefore, the determination result in the failure determination means can be confirmed by shifting the operation mode to the fail-safe mode based on the temperature difference. That is, the failure of the electric water pump can be confirmed twice, and the reliability of the determination result can be improved.

  As a result, according to the second cooling device of the present invention, it is possible to prevent the internal combustion engine from overheating when the electric water pump fails. In addition, it is possible to prevent a transition to the fail safe mode after overheating or a transition to the fail safe mode in a situation where the overheating does not actually occur. That is, it becomes possible to appropriately shift the vehicle operation mode to the fail-safe mode.

  Note that, depending on the measured temperature difference of the cooling medium, the operation mode may be shifted to the above-described limited travel mode or the like.

  In another aspect of the second cooling device of the present invention, the transition control means includes storage means for storing the temperature of the cooling medium measured when it is determined that at least the electric water pump has failed. Including.

  According to this aspect, for example, the temperature of the cooling medium measured when it is determined that the electric water pump stored in the storage means that is a memory has failed, the accumulated value of the detected air amount is the predetermined accumulation Not only used to determine the difference between the measured temperature of the cooling medium when the value is reached, but for example, if the measured temperature of the cooling medium when determined was 90 degrees Celsius, It is possible to shift the operation mode to the fail safe mode by another control means without obtaining the temperature difference.

  Further, the temperature of the cooling medium may be stored in the storage unit regularly, irregularly, or continuously. In this way, if the temperature of the cooling medium changes greatly after the determined time and before the accumulated value of the detected air amount reaches the predetermined accumulated value, that is, the electric water pump has failed. Thus, when the temperature of the internal combustion engine is reflected in the temperature of the cooling medium measured by the temperature measuring means with a certain time delay, it is determined based on or at the temperature of the cooling medium at that time. The operation mode can be shifted to the fail-safe mode based on the difference between the measured temperature of the coolant and the temperature of the coolant, and a quick response is possible.

  In another aspect of the second cooling device of the present invention, the transition control means includes temperature difference determination means for determining whether the difference is larger than the predetermined temperature difference, and the difference is the predetermined temperature difference. The operation mode is shifted to the fail-safe mode when it is determined that the difference is larger, and the operation mode is not shifted to the fail-safe mode when the difference is determined to be smaller than the predetermined temperature difference.

  According to this aspect, the temperature difference determination means, when it is determined that the electric water pump has failed, the temperature of the cooling medium measured when it is determined that the electric water pump has failed, It is determined whether or not the difference between the temperature of the detected cooling medium and the temperature of the cooling medium measured when the cumulative value of the air amount reaches the predetermined cumulative value is greater than the predetermined temperature difference. The transition control means shifts the operation mode to the failsafe mode when it is determined that the difference is larger than the predetermined temperature difference. Thereby, it can transfer to fail safe mode promptly and it can prevent that an internal combustion engine overheats.

  Further, when it is determined that the difference is smaller than the predetermined temperature difference, the shift control means does not shift the operation mode to the fail-safe mode, that is, remains in the normal travel mode. In other words, if the difference is equal to or less than the predetermined temperature difference, the transition to the fail safe mode is prohibited.

  The operation and other advantages of the present invention will become apparent from the best mode for carrying out the invention described below.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<First Embodiment>
A first embodiment of the cooling device of the present invention will be described with reference to FIGS.

  First, the configuration of the cooling device according to the present embodiment will be described with reference to FIG. FIG. 1 is a block diagram of a cooling device according to the present embodiment.

  In FIG. 1, a cooling device 1 is mounted on a vehicle such as an automobile together with an internal combustion engine 11 as an engine. The cooling device 1 includes a circulation passage 21 through which a cooling medium such as LLC that cools the internal combustion engine 11 flows, and an electric water pump 22 that circulates the cooling medium. The circulation flow path 21 includes a radiator 25, a thermostat 24, a radiator flow path 21 a that passes through the radiator 25, a bypass flow path 21 b that bypasses the radiator 25, and a water jacket 21 c provided in the internal combustion engine 11. Yes.

  The cooling device 1 further includes a temperature sensor 26 that measures the temperature of the cooling medium, a pump sensor 23 that monitors the operating state of the electric water pump 22, and an electric water pump 22 that fails based on the monitored operating state. An electronic fuel injection control unit (EFIECU) 30 for determining whether or not the electric fan, and a radiator fan 50 as an example of the “electric fan” according to the present invention, provided between the radiator 25 and the internal combustion engine 11, It is configured with. The EFIECU 30 is configured to perform various electronic controls in the internal combustion engine 11 or in a vehicle on which the internal combustion engine 11 is mounted, in addition to such a failure determination of the electric water pump 22. In other words, in this embodiment, a part of the EFIECU 30 for various electronic controls is used as a part of the cooling device 1. The pump sensor 23, the temperature sensor 26, and the EFIECU 30 according to the present embodiment are examples of the “monitoring unit”, “temperature measuring unit”, and “failure determining unit” according to the present invention, respectively.

  The EFIECU 30 includes a CPU 301, a non-volatile memory such as an EEPROM (Electronically Erasable and Programmable Read Only Memory), a backup ROM, a flash memory, etc., and a memory 302 as an example of the “storage means” according to the present invention, and each sensor. And an input / output circuit 303 that inputs and outputs such signals.

  A vehicle including the cooling device 1 includes an internal combustion engine 11 and an electric motor 40. An intake passage 12 that supplies air to the internal combustion engine 11 is connected to the internal combustion engine 11. The intake passage 12 is an air flow as an example of the “air amount detection means” according to the present invention, which detects the amount of air sucked into the electric throttle 13 and the internal combustion engine 11 that adjusts the amount of air supplied to the internal combustion engine 11. It has a meter 14.

  The water jacket 21c is connected to the radiator 25 via the radiator flow path 21a. An electric water pump 22 is provided in the vicinity of the inlet (left side in FIG. 1) of the water jacket 21c. The electric water pump 22 circulates the cooling medium in the direction indicated by the arrow in FIG. During this circulation, the cooling medium absorbs heat from the internal combustion engine 11 and rises in temperature in the process of passing through the water jacket 21c. The cooling medium whose temperature has been increased releases heat in the process of passing through the radiator 25 to lower the temperature.

  A bypass channel 21b is connected to the radiator channel 21a. One end of the bypass channel 21b is connected between the outlet of the water jacket 21c (the right side in FIG. 1) and the radiator 25. The other end of the bypass flow path 21 b is connected between the radiator 25 and the electric water pump 22.

  A thermostat 24 is provided at a connection portion between the other end of the bypass flow path 21b and the radiator flow path 22a. The opening of the thermostat 24 changes depending on the temperature of the cooling medium, and adjusts the flow rate of the cooling medium flowing through the radiator flow path 21a and the bypass flow path 21b.

  The pump sensor 23 monitors the operating state of the electric water pump 22 and transmits a monitoring signal indicating the operating state to the EFIECU 30. Specifically, the pump sensor 23 may monitor the rotational speed of the electric water pump 22 as an operation state to be monitored, in other words, may count or detect the rotational speed. In this case, a monitoring signal indicating the rotational speed (that is, the rotational speed signal) is output. Alternatively, the pump sensor 23 may monitor a current value for driving the electric water pump 22 as an operation state to be monitored, in other words, measure or detect the current value. In this case, a monitoring signal indicating a current value (that is, a current value signal) is output. In addition, when counting the rotation speed of the electric water pump 22, the pump sensor 23 may be a counter, and when measuring a current value, the pump sensor 23 may be an ammeter.

  The EFI ECU 30 determines whether or not the electric water pump 22 has failed based on the operating state of the electric water pump 22 indicated by the monitoring signal from the pump sensor 23. Specifically, for example, based on the rotational speed of the electric water pump 22 indicated by the rotational speed signal as the monitoring signal from the pump sensor 23 or related to the electric water pump 22 indicated by the current value signal. Based on the current value, it is determined whether or not the electric water pump 22 has failed.

  More specifically, for example, if the pump sensor 23 monitors the rotational speed of the electric water pump, it is determined whether the rotational speed is equal to or less than a predetermined value, or the current value is monitored. If so, it is determined whether or not the current value is equal to or less than a predetermined value, and it is determined whether or not the electric water pump 22 has failed. The predetermined value for determining the failure of the electric water pump 22 is that the motor of the electric water pump 22 is stopped regardless of whether the operation state of the electric water pump 22 monitored by the pump sensor 23 is the rotational speed or the current value. Theoretically, it is zero. However, in reality, there is an error due to, for example, the monitoring accuracy of the pump sensor 23, and so the value is set in consideration of the error.

  When the EFIECU 30 determines that the electric water pump 22 is out of order, the EFIECU 30 compares the temperature of the cooling medium measured by the temperature sensor 26 with a predetermined temperature T1 stored in the memory 302. Here, the predetermined temperature T1 according to the present embodiment is set to, for example, 80 degrees Celsius in consideration of the deterioration of the responsiveness of the measured temperature of the cooling medium due to no circulation of the cooling medium. It is an example of a “first predetermined temperature” according to the present invention.

  When it is determined that the temperature of the cooling medium is higher than the predetermined temperature T1, the EFIECU 30 shifts the operation mode of the vehicle to the failsafe mode. That is, the internal combustion engine 11 is stopped and the electric motor 40 is shifted to the traveling mode. Further, when it is determined that the temperature of the cooling medium is lower than the predetermined temperature T1, the operation mode is not shifted to the fail safe mode. The EFIECU 30 according to the present embodiment is an example of the “temperature determination unit” and the “transition control unit” according to the present invention.

  Next, the temperature control process executed by the EFIECU 30 in the cooling device 1 configured as described above will be described with reference to the flowchart of FIG. This temperature control process is mainly executed periodically while the vehicle is running, for example, regularly or irregularly, every few seconds to every few seconds.

  In FIG. 2, first, the EFIECU 30 determines whether or not the vehicle is in a mode in which the vehicle travels with the electric motor 40 (Electric Vehicle travel: EV travel), that is, a fail safe mode (step S101). If it is in fail-safe mode (step S101: Yes), the process is terminated. When the vehicle is not in the fail-safe mode (step S102: No), the vehicle is traveling using both the internal combustion engine 11 and the electric motor 40 (hybrid vehicle traveling: HV traveling) (step S102). That is, it is a normal driving mode that is a normal driving mode. Therefore, it is subsequently determined whether or not the electric water pump 22 has failed based on the operating state of the electric water pump 22 monitored by the pump sensor 23 (step S103).

  If it is determined that the electric water pump 22 has failed (step S103: Yes), the temperature of the cooling medium measured by the temperature sensor 26 is compared with a predetermined temperature T1 stored in the memory 302. (Step S104). As a result of this comparison, when it is determined that the temperature of the cooling medium is higher than the predetermined temperature T1 (step S104: Yes), the EFIECU 30 shifts the vehicle to the fail-safe mode (step S106) and ends the process. When the temperature of the cooling medium is lower than the predetermined temperature T1 (step S104: No), the HV traveling is maintained and the process is terminated. That is, the traveling in the normal traveling mode is continued.

  When it is determined that the electric water pump 22 has not failed (step S103: No), subsequently, the temperature of the cooling medium measured by the temperature sensor 26 and the memory 302 stored in the memory " It is compared with a predetermined temperature T2 as an example of “second predetermined temperature” (step S105). Here, the predetermined temperature T2 is, for example, 115 degrees Celsius, and is a temperature for determining whether or not to shift to the fail-safe mode at the normal time.

  When it is determined that the temperature of the cooling medium is higher than the predetermined temperature T2 (step S105: Yes), the EFIECU 30 shifts the vehicle to the fail-safe mode (step S106) and ends the process. When it is determined that the temperature of the cooling medium is lower than the predetermined temperature T2 (step S105: No), the HV traveling is maintained and the process is terminated. That is, the traveling in the normal traveling mode is continued.

  As described above, in the present embodiment, the EFIECU 30 determines whether or not the electric water pump 22 has failed based on the operating state monitored by the pump sensor 23 such as the rotation speed and current value of the electric water pump 22. judge. When it is determined that there is a failure, it is determined whether or not the measured temperature response is deteriorated due to the absence of circulation of the cooling medium, and it is determined whether or not the temperature is higher than the predetermined temperature T1. If it is determined that the vehicle is too high, the vehicle is shifted to the fail-safe mode. Therefore, according to the present embodiment, it is possible to prevent the internal combustion engine 11 from overheating when the electric water pump 22 fails.

<Second Embodiment>
A second embodiment of the cooling device of the present invention will be described with reference to FIG. The second embodiment is the same as the configuration of the first embodiment except that the temperature control process in the EFIECU 30 is different. Therefore, the description which overlaps with 1st Embodiment is abbreviate | omitted about 2nd Embodiment.

  In the present embodiment, when it is determined that the electric water pump 22 is out of order, first, in the EFIECU 30, the CPU 301 detects the temperature of the cooling medium measured by the temperature sensor 26 and a predetermined value stored in the memory 302. The temperature T3 is compared. Here, the predetermined temperature T3 according to the present embodiment is set to, for example, 80 degrees Celsius in consideration of the deterioration of the responsiveness of the measured temperature of the cooling medium due to no circulation of the cooling medium. It is an example of a “third predetermined temperature” according to the present invention.

  When the temperature of the cooling medium is higher than the predetermined temperature T3, the EFIECU 30 sets the opening of the electric throttle 13 to, for example, 8 degrees regardless of the opening of the accelerator. That is, the vehicle operation mode is shifted to the limited travel mode. Here, the opening degree of the electric throttle 13 refers to the angle of the throttle valve when the opening degree of the throttle valve is 0 degrees. The opening degree of the electric throttle 13 may be a fixed value, or may be variable according to the temperature of the cooling medium, for example.

  Next, the EFIECU 30 compares the temperature of the cooling medium again measured by the temperature sensor 26 with a predetermined temperature T4 stored in the memory 302. Here, the predetermined temperature T4 according to the present embodiment is set to, for example, 90 degrees Celsius in consideration of the deterioration of the responsiveness of the measured temperature of the cooling medium due to no circulation of the cooling medium. It is another example of the “first predetermined temperature” according to the present invention. When the temperature of the cooling medium is higher than the predetermined temperature T4, the EFIECU 30 shifts the vehicle to the fail safe mode.

  Next, the temperature control process executed by the EFIECU 30 in the present embodiment will be described with reference to the flowchart of FIG. This temperature control process is mainly executed periodically while the vehicle is running, for example, regularly or irregularly, every few seconds to every few seconds.

  In FIG. 3, first, the EFIECU 30 determines whether or not the vehicle is in a fail-safe mode (EV traveling) (step S201). If it is in fail-safe mode (step S201: Yes), the process is terminated. When the vehicle is not in the fail-safe mode (step S202: No), the vehicle is in a traveling mode (HV traveling) in which the internal combustion engine 11 and the electric motor 40 are used together, that is, a normal traveling mode that is a traveling mode in a normal state (step S202). Therefore, it is subsequently determined whether or not the electric water pump 22 has failed based on the operating state of the electric water pump 22 monitored by the pump sensor 23 (step S203).

  If it is determined that the electric water pump 22 is out of order (step S203: Yes), it is subsequently determined whether or not it is a limited travel mode (step S204). If it is in the limited travel mode (step S204: Yes), the process has already been shifted to the limited travel mode in the previous cycle in the temperature control process, so the process of step S207 described later is performed.

  If it is not the limited travel mode (step S204: No), the temperature of the cooling medium measured by the temperature sensor 26 is compared with a predetermined temperature T3 stored in the memory 302 (step S205). When the temperature of the cooling medium is lower than the predetermined temperature T3 (step S205: No), the HV traveling is maintained and the process is terminated. That is, the traveling in the normal traveling mode is continued.

  When the temperature of the cooling medium is higher than the predetermined temperature T3 (step S205: Yes), the EFIECU 30 shifts the operation mode to the limited travel mode and limits the opening of the electric throttle 13 to, for example, 8 degrees (step S206). Subsequently, the temperature of the cooling medium again measured by the temperature sensor 26 is compared with a predetermined temperature T4 stored in the memory 302 (step S207). When the temperature of the cooling medium is lower than the predetermined temperature T4 (step S207: No), the limited travel mode is maintained and the process is terminated.

  When the temperature of the cooling medium is higher than the predetermined temperature T4 (step S207: Yes), the EFIECU 30 shifts to the fail safe mode (step S212) and ends the process.

  When it is determined that the electric water pump 22 has not failed (step S203: No), it is subsequently determined whether or not it is the limited travel mode (step S208). If it is in the limited travel mode (step S208: Yes), the process has already been shifted to the limited travel mode in the previous cycle in the temperature control process, so the process of step S211 described later is performed.

  When the travel mode is not the limit travel mode (step S208: No), the temperature of the cooling medium measured by the temperature sensor 26 and the predetermined temperature T5 as an example of the “fourth predetermined temperature” according to the present invention stored in the memory 302. (Step S209). Here, the predetermined temperature T5 is, for example, 105 degrees Celsius, and is a temperature for shifting to the limited travel mode at the normal time. When the temperature of the cooling medium is lower than the predetermined temperature T5 (step S209: No), the HV traveling is maintained and the process is terminated. That is, the traveling in the normal traveling mode is continued.

  When the temperature of the cooling medium is higher than the predetermined temperature T5 (step S209: Yes), the EFIECU 30 shifts the operation mode to the limited travel mode, and limits the opening of the electric throttle 13 to, for example, 8 degrees (step S210). . Subsequently, the temperature of the cooling medium newly measured by the temperature sensor 26 is compared with a predetermined temperature T6 as another example of the “second predetermined temperature” according to the present invention stored in the memory 302 (step S211). ). Here, the predetermined temperature T6 is, for example, 115 degrees Celsius, and is a temperature for shifting to the fail-safe mode at the normal time. When the temperature of the cooling medium is lower than the predetermined temperature T6 (step S211: No), the limited travel mode is maintained and the process is terminated.

  When the temperature of the cooling medium is higher than the predetermined temperature T6 (step S211: Yes), the EFIECU 30 shifts the operation mode to the failsafe mode (step S212), and ends the process.

  As described above, in the present embodiment, the EFIECU 30 determines whether or not the electric water pump 22 has failed based on the operating state monitored by the pump sensor 23 such as the rotation speed and current value of the electric water pump 22. judge. If it is determined that there is a failure, it is first determined whether or not the temperature of the cooling medium is higher than a predetermined temperature T3. If the temperature is higher than the predetermined temperature T3, the operation mode is shifted to the limited travel mode. Next, it is determined again whether or not the temperature of the cooling medium is higher than the predetermined temperature T4. When the temperature is higher than the predetermined temperature T4, the operation mode is shifted to the fail-safe mode. Therefore, according to the present embodiment, it is possible to prevent the internal combustion engine 11 from overheating when the electric water pump 22 fails. In addition, since the vehicle can travel using the internal combustion engine 11 until the temperature of the cooling medium reaches the predetermined temperature T4, the time or travel distance until the operation mode is shifted to the fail-safe mode can be lengthened.

<Third Embodiment>
A third embodiment of the cooling device of the present invention will be described with reference to FIGS. The third embodiment is the same as the configuration of the first embodiment except that the temperature control process in the EFIECU 30 is different. Therefore, the description which overlaps with 1st Embodiment about 3rd Embodiment is abbreviate | omitted.

  In the present embodiment, the memory 302 has a plurality of ignition retardation maps as shown in FIG. Here, FIGS. 4A and 4B are examples of a normal high water temperature ignition delay map and a failure high water temperature ignition delay map, respectively. Here, “normal time” and “failure” refer to “when the electric water pump 22 is not broken” and “when it is broken”, respectively. Such a map may be composed of data acquired through experiments, simulations, and the like. Specifically, for example, data on the degree of increase or decrease in the temperature of the cooling medium at various retardation amounts may be acquired, and a map may be configured based on the data or the like.

  When it is determined that the electric water pump 22 has failed, in the EFIECU 30, the CPU 301 compares the temperature of the cooling medium measured by the temperature sensor 26 with a predetermined temperature T7 stored in the memory 302. When the temperature of the cooling medium is higher than the predetermined temperature T7, in the EFIECU 30, the CPU 301 selects a failure high water temperature ignition delay map from the memory 302. Accordingly, in consideration of the fact that the response of the temperature sensor 26 is delayed when the electric water pump 22 has a failure of the coolant flow rate, the ignition timing is set at a lower temperature than that at the normal time, for example, 60 degrees Celsius or more. Is retarded to suppress the temperature rise of the combustion chamber wall of the internal combustion engine 11. The predetermined temperature T7 according to the present embodiment is an example of the “fifth predetermined temperature” according to the present invention.

  Next, the temperature control process executed by the EFIECU 30 in the present embodiment will be described with reference to the flowchart of FIG. In this embodiment, the process between step S203 and step S204 and the process between step S203 and step S208 of the temperature control process of FIG. 3 in the second embodiment is modified as shown in FIG. Other parts are the same as those in the second embodiment. Therefore, the description which overlaps with 2nd Embodiment is abbreviate | omitted about 3rd Embodiment. This temperature control process is mainly executed periodically while the vehicle is running, for example, regularly or irregularly, every few seconds to every few seconds.

  In FIG. 5, when the EFIECU 30 determines that the electric water pump 22 is out of order based on the operating state of the electric water pump 22 monitored by the pump sensor 23 (step S203: Yes), the temperature sensor 26 The measured temperature of the cooling medium is compared with a predetermined temperature T7 stored in the memory 302 (step S301). Here, the predetermined temperature T7 is, for example, 60 degrees Celsius, and is a temperature to be switched to the high water temperature ignition delay map at the time of failure.

  When the temperature of the cooling medium is higher than the predetermined temperature T7 (step S301: Yes), the EFIECU 30 selects a failure high water temperature ignition delay map as shown in FIG. 4B (step S302). In other words, the operation mode is switched from the normal running mode to the high water temperature ignition delay mode at the time of failure or maintained in the high water temperature ignition delay mode at the time of failure. When the temperature of the cooling medium is lower than the predetermined temperature T7 (step S301: No), the process is terminated. That is, the traveling in the normal traveling mode is continued.

  When it is determined that the electric water pump 22 has not failed (step S203: No), the temperature of the cooling medium measured by the temperature sensor 26 and the “sixth predetermined” according to the present invention stored in the memory 302 are stored. It is compared with a predetermined temperature T8 as an example of “temperature” (step S303). Here, the predetermined temperature T8 is, for example, 80 degrees Celsius, and is a temperature to be switched to the normal high water temperature ignition delay map.

  When the temperature of the cooling medium is higher than the predetermined temperature T8 (step S303: Yes), the EFIECU 30 selects a normal high water temperature ignition retardation map as shown in FIG. 4A (step S304). That is, the operation mode is switched from the normal running mode to the normal high water temperature ignition delay mode, or is maintained in the normal high water temperature ignition delay mode. When the temperature of the cooling medium is lower than the predetermined temperature T8 (step S303: No), the process ends. That is, the traveling in the normal traveling mode is continued.

  As described above, in the present embodiment, when it is determined that the electric water pump 22 has failed, the ignition delay map is switched, and ignition is performed from a lower temperature than in a normal time in which the electric water pump 22 has not failed. By retarding the timing, the temperature rise of the combustion chamber wall of the internal combustion engine 11 is suppressed. Furthermore, the operation mode is shifted to the limited travel mode or the fail safe mode according to the temperature of the cooling medium. Therefore, according to the present embodiment, it is possible to prevent the internal combustion engine 11 from overheating when the electric water pump 22 fails. Further, until the temperature for transition to the fail-safe mode (for example, 90 degrees Celsius) is reached, the ignition timing is retarded, thereby suppressing the temperature increase of the internal combustion engine 11 or promoting the temperature decrease. Or it can drive | work in the state near normal driving | running | working.

<Fourth embodiment>
A fourth embodiment according to the cooling device of the present invention will be described with reference to FIG. The fourth embodiment is the same as the configuration of the first embodiment except that the temperature control process in the EFIECU 30 is different. Therefore, about 4th Embodiment, the description which overlaps with 1st Embodiment is abbreviate | omitted.

  In this embodiment, when it is determined that the electric water pump 22 has failed, the EFIECU 30 operates the radiator fan 50 to air-cool the internal combustion engine 11 regardless of the temperature of the cooling medium, and the temperature of the internal combustion engine 11. Suppresses the rise.

  Next, the temperature control process executed by the EFIECU 30 in the present embodiment will be described with reference to the flowchart of FIG. In the present embodiment, the processing between step S203 and step S204 and the processing between step S203 and step S208 of the temperature control processing of FIG. 3 in the second embodiment is modified as shown in FIG. Other parts are the same as those in the second embodiment. Therefore, the description which overlaps with 2nd Embodiment is abbreviate | omitted about 4th Embodiment. This temperature control process is mainly executed periodically while the vehicle is running, for example, regularly or irregularly, every few seconds to every few seconds.

  When the EFIECU 30 determines that the electric water pump 22 has failed based on the operating state of the electric water pump 22 monitored by the pump sensor 23 (step S203: Yes), the EFIECU 30 relates to the temperature of the cooling medium. If not, the radiator fan 50 is operated (step S401).

  When it is determined that the electric water pump 22 has not failed (step S203: No), the temperature of the cooling medium measured by the temperature sensor 26 is compared with a predetermined temperature T9 stored in the memory 302 (step S203). S402). Here, the predetermined temperature T9 according to the present embodiment is, for example, 100 degrees Celsius, and is an example of the “seventh predetermined temperature” according to the present invention. That is, it is the temperature at which the radiator fan 50 is operated in order to avoid overheating during normal travel.

  When the temperature of the cooling medium is higher than the predetermined temperature T9 (step S402: Yes), the EFIECU 30 operates the radiator fan 50 (step S403). When the temperature of the cooling medium is lower than the predetermined temperature T9 (step S402: No), the process is terminated. That is, the traveling in the normal traveling mode is continued.

  As described above, in this embodiment, when it is determined that the electric water pump 22 has failed, the EFIECU 30 operates the radiator fan 50 to increase the temperature of the internal combustion engine 11 regardless of the temperature of the cooling medium. Suppress. Furthermore, the operation mode is shifted to the limited travel mode or the fail safe mode according to the temperature of the cooling medium. Therefore, according to the present embodiment, it is possible to prevent the internal combustion engine 11 from overheating when the electric water pump 22 fails. Furthermore, until the temperature for transition to the fail-safe mode (for example, 90 degrees Celsius) is reached, the radiator fan 50 is used to suppress the temperature increase of the internal combustion engine 11 or promote the temperature decrease. It is possible to travel in a state close to normal traveling.

<Fifth Embodiment>
A fifth embodiment of the cooling device of the present invention will be described with reference to FIG. The fifth embodiment is the same as the configuration of the first embodiment except that the temperature control process in the EFIECU 30 is different. Therefore, the description which overlaps with 1st Embodiment about 5th Embodiment is abbreviate | omitted.

  In this embodiment, when it is determined that the electric water pump 22 has failed, first, in the EFIECU 30, the CPU 301 detects the temperature of the cooling medium measured by the temperature sensor 26 and the predetermined temperature stored in the memory 302. Compare with T10. Here, the predetermined temperature T10 according to the present embodiment is, for example, an upper limit temperature that can be controlled by controlling the flow rate of the cooling medium by the thermostat 24, and is an example of the “first predetermined temperature” according to the present invention.

  When the temperature of the cooling medium is higher than the predetermined temperature T10, the EFIECU 30 shifts the operation mode to the failsafe mode. Here, a typical example of the fail safe mode is the EV traveling (step S106) or the narrow fail safe mode in the first embodiment or the like. However, the present invention is not limited to this, and the “fail safe mode” herein may be a broad fail safe mode including a limited travel mode, an operation mode for switching an ignition delay angle, an operation mode for operating an electric fan, and the like. .

  With this configuration, for example, when the electric water pump 22 is temporarily stopped or the pump sensor 23 has failed, and it is determined that the electric water pump 22 has failed, that is, an erroneous determination has been made. In some cases, it is possible to prevent the vehicle from immediately entering the fail-safe mode. Moreover, even if the electric water pump 22 is out of order, the internal combustion engine 11 can be prevented from overheating.

  Next, the temperature control process executed by the EFIECU 30 in the present embodiment will be described with reference to the flowchart of FIG. This temperature control process is mainly executed periodically while the vehicle is running, for example, regularly or irregularly, every few seconds to every few seconds.

  In FIG. 7, first, the EFIECU 30 determines whether or not the electric water pump 22 has failed based on the operating state of the electric water pump 22 monitored by the pump sensor 23 (step S501). When it is determined that the electric water pump 22 has not failed (step S501: No), the normal running is continued (step S506), and the process is terminated. Here, the normal traveling according to the present embodiment refers to HV traveling using both the internal combustion engine 11 and the electric motor 40 (that is, traveling in the normal traveling mode).

  When it is determined that the electric water pump 22 is out of order (step S501: Yes), the temperature of the cooling medium measured by the temperature sensor 26 is compared with a predetermined temperature T10 stored in the memory 302 (step S502). ). Here, the predetermined temperature T10 according to the present embodiment is, for example, 95 degrees Celsius.

  When the temperature of the cooling medium is higher than the predetermined temperature T10 (step S502: Yes), the EFIECU 30 shifts the operation mode to the failsafe mode (step S503) and ends the process. When the temperature of the cooling medium is lower than the predetermined temperature T10 (step S502: No), it is subsequently determined whether or not the operation mode is a fail-safe mode (step S504). When it is not the fail-safe mode (step S504: No), the normal running is continued (step S506), and the process is terminated.

  If the mode is the fail safe mode (step S504: Yes), the temperature of the cooling medium measured by the temperature sensor 26 is compared with a predetermined temperature T11 stored in the memory 302 (step S505). Here, the predetermined temperature T11 is, for example, 92 degrees Celsius. When the temperature of the cooling medium is higher than the predetermined temperature T11 (step S505: Yes), the fail safe mode is maintained and the process is terminated. When the temperature of the cooling medium is lower than the predetermined temperature T11 (step S505: No), the process shifts to the normal travel (step S506), that is, returns to the normal travel mode, and the process ends.

  As described above, in the present embodiment, when it is determined that the electric water pump 22 is out of order, the operation is shifted to the fail-safe mode at a temperature higher than the upper limit temperature that can be controlled by the flow rate control of the cooling medium by the thermostat 24. As a result, if the determination is incorrect, the electric water pump 22 is normally driven, the cooling medium is circulated, and the temperature can be controlled by the thermostat 24. On the other hand, even if the electric water pump 22 is out of order, the temperature of the cooling medium that shifts to the fail-safe mode is lower than normal, so that the internal combustion engine 11 can be prevented from overheating.

  Therefore, according to the present embodiment, it is possible to prevent the transition to the fail safe mode in a situation where the overheating does not actually occur. Further, when the temperature of the cooling medium is higher than the predetermined temperature, since the transition to the fail-safe mode is promptly performed, it is possible to prevent the internal combustion engine 11 from being overheated.

<Sixth Embodiment>
6th Embodiment which concerns on the cooling device of this invention is described with reference to FIG.8 and FIG.9. The sixth embodiment is the same as the configuration of the first embodiment except that the temperature control process in the EFIECU 30 is different. Therefore, the description which overlaps with 1st Embodiment about 6th Embodiment is abbreviate | omitted.

  In this embodiment, when it is determined that the electric water pump 22 has failed, the temperature sensor 26 measures the first temperature of the cooling medium when it is determined that the electric water pump 22 has failed, Stored in the memory 302. Before and after the measurement of the first temperature, the EFIECU 30 is an example of the “cumulative value of air amount” according to the present invention based on a signal indicating the amount of air taken into the internal combustion engine 11 from the air flow meter 14. Detection of the accumulated air amount Va is started.

  When the accumulated air amount Va reaches a predetermined accumulated value Vath stored in the memory 302, the EFIECU 30 measures the second temperature of the cooling medium measured by the temperature sensor 26 and the first temperature stored in the memory 302. The temperature difference is calculated. When the temperature difference is larger than the predetermined temperature difference ΔT stored in the memory 302, the EFIECU 30 shifts the vehicle operation mode to the failsafe mode. Here, the EFIECU 30 according to the present embodiment is an example of the “temperature difference determination unit” according to the present invention.

  Here, referring to FIG. 8, the combustion chamber wall temperature and cooling of the internal combustion engine 11 when the electric water pump 22 has failed (ie, at the time of failure) and when it has not failed (ie, at the time of normal operation). A description will be given of the temporal change in the medium temperature. FIG. 8 is a graph showing an example of temporal changes in the combustion chamber wall temperature and the cooling medium temperature. In FIG. 8, the solid line a and the broken line c are the combustion chamber wall temperature and the cooling medium temperature at the time of failure, respectively, and the one-dot chain line b and the two-dot chain line d are the combustion chamber wall temperature and the cooling medium temperature at the normal time, respectively. It is.

  As can be seen from FIG. 8, the temperature of the combustion chamber wall and the temperature of the cooling medium at a normal time are substantially constant at a certain temperature. Therefore, there is almost no temperature change, that is, temperature difference in a certain period. On the other hand, at the time of failure, the temperature continues to rise, resulting in a temperature difference. Even if the electric water pump 22 fails near the rise of the graph (that is, near the left side of the graph shown in FIG. 8), the degree of temperature rise differs between the failure and the normal time. It is possible to cope with this by changing the predetermined temperature difference ΔT according to the time since the start of the engine or the first temperature of the cooling medium measured when it is determined that the electric water pump 22 has failed. .

  Next, the temperature control process executed by the EFIECU 30 in the present embodiment will be described with reference to the flowchart of FIG. This temperature control process is mainly executed periodically while the vehicle is running, for example, regularly or irregularly, every few seconds to every few seconds.

  In FIG. 9, first, the EFIECU 30 determines whether or not the electric water pump 22 has failed based on the operating state of the electric water pump 22 monitored by the pump sensor 23 (step S601). If it is determined that the electric water pump has not failed (step S601: No), normal driving is continued (step S609), and the process is terminated. Here, the normal traveling according to the present embodiment refers to HV traveling using both the internal combustion engine 11 and the electric motor 40 (that is, traveling in the normal traveling mode).

  When it is determined that the electric water pump 22 is out of order (step S601: Yes), the first temperature of the cooling medium is measured by the temperature sensor 26 (step S602), and the EFI ECU 30 receives the internal combustion engine 11 from the air flow meter 14. The accumulated air amount Va is detected based on a signal indicating the amount of air sucked in (step S603).

  Subsequently, it is determined whether or not the accumulated air amount Va is equal to or greater than a predetermined air amount Vath (step S604). When the accumulated air amount Va is smaller than the predetermined air amount Vath (step S604: No), the normal running is continued (step S609), and the process is temporarily terminated. In addition, since the temperature control process according to the present embodiment is periodically executed, even if the accumulated air amount Va is smaller than the predetermined air amount Vath in the temperature control process executed this time, it is executed after the next time. In the temperature control process to be performed, if the accumulated air amount Va is equal to or greater than the predetermined air amount Vath, the processing after step S605 described later is performed. In this case, for example, a flag that it is determined that the electric water pump 22 has failed may be set, and the temperature control process from the next time may be started from step S603.

  When the accumulated air amount Va is equal to or larger than the predetermined air amount Vath (step S604: Yes), the temperature sensor 26 measures the second temperature of the cooling medium (step S605), and the EFIECU 30 detects the temperature difference between the first and second temperatures. Is obtained (step S606).

  Subsequently, it is determined whether or not the temperature difference is larger than the predetermined temperature difference ΔT (step S607). If the temperature difference is larger than the predetermined temperature difference ΔT (step S607: Yes), the EFIECU 30 shifts the operation mode to the failsafe mode. (Step S608), and the process ends. When the temperature difference is smaller than the predetermined temperature difference ΔT (step S607: No), the normal running is continued (step S609), and the process is terminated.

  As described above, in the present embodiment, when it is determined that the electric water pump 22 is out of order, if the temperature difference is larger than the predetermined temperature difference ΔT, the operation mode is shifted to the fail-safe mode, and the temperature difference is the predetermined temperature. If the difference is smaller than ΔT, the operation mode is not shifted to the fail-safe mode, that is, the normal operation mode is maintained.

  Therefore, according to the present embodiment, it is possible to prevent the internal combustion engine 11 from overheating when the electric water pump 22 fails. In addition, it is possible to prevent a transition to the fail safe mode after overheating or a transition to the fail safe mode in a situation where the overheating does not actually occur.

  Note that the present invention is not limited to the above-described embodiment, and can be appropriately changed within the scope of the invention that can be read from the claims and the entire specification, or in a range that does not violate the idea. The apparatus is also included in the technical scope of the present invention.

It is a block diagram of the cooling device concerning a 1st embodiment of the present invention. It is a flowchart which shows the process in EFIECU which concerns on 1st Embodiment of this invention. It is a flowchart which shows the process in EFIECU which concerns on 2nd Embodiment of this invention. It is an example of the normal time high water temperature ignition delay map (a) and the high water temperature ignition delay map (b) at the time of a failure concerning a 3rd embodiment of the present invention. It is a flowchart which shows the process in EFIECU which concerns on 3rd Embodiment of this invention. It is a flowchart which shows the process in EFIECU which concerns on 4th Embodiment of this invention. It is a flowchart which shows the process in EFIECU which concerns on 5th Embodiment of this invention. It is a graph which shows an example of the time change of the combustion chamber wall temperature and cooling medium temperature of an internal combustion engine. It is a flowchart which shows the process in EFIECU which concerns on 6th Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Cooling device, 11 ... Internal combustion engine, 12 ... Intake passage, 13 ... Electric throttle, 14 ... Air flow meter, 21 ... Circulation flow path, 22 ... Electric water pump, 23 ... Pump sensor, 24 ... Thermostat, 25 ... Radiator, 26 ... Temperature sensor, 30 ... EFIECU, 40 ... Electric motor, 50 ... Radiator fan

Claims (10)

A cooling device for cooling the internal combustion engine in a vehicle including the internal combustion engine and an electric motor,
A circulation path through which a cooling medium for cooling the internal combustion engine flows;
An electric water pump for circulating the cooling medium;
Temperature measuring means for measuring the temperature of the cooling medium;
Failure determination means for determining whether or not the electric water pump has failed; and
Transition control means for transitioning the operation mode of the vehicle to the fail-safe mode on condition that the measured temperature is higher than a first predetermined temperature when it is determined that the electric water pump has failed. A cooling device characterized by that. The failure determination means includes
Monitoring means for monitoring the operating state of the electric water pump;
The cooling device according to claim 1, wherein it is determined whether or not the electric water pump has failed based on the monitored operation state. The transition control means includes
Temperature determination means for determining whether the measured temperature is higher than the first predetermined temperature when it is determined that the electric water pump is malfunctioning;
When it is determined that the measured temperature is higher than the first predetermined temperature, the operation mode is shifted to the fail-safe mode, and when the measured temperature is determined to be lower than the first predetermined temperature. The cooling apparatus according to claim 1, wherein the operation mode is not shifted to the fail-safe mode. The transition control means, when it is determined that the electric water pump has not failed, the operation mode on the condition that the measured temperature is higher than a second predetermined temperature higher than the first predetermined temperature. The cooling device according to claim 1, wherein the cooling device is shifted to the fail-safe mode. The vehicle further includes an electric throttle that adjusts a supply amount of air to the internal combustion engine,
The fail safe mode is a mode in which the vehicle is driven by the electric motor,
When it is determined that the electric water pump has failed, the transition control means has the measured temperature lower than the first predetermined temperature and higher than a third predetermined temperature lower than the first predetermined temperature. The cooling device according to any one of claims 1 to 4, wherein the operation mode is shifted to a limited travel mode that restricts the opening of the electric throttle. And further comprising storage means having a plurality of ignition retardation maps,
The cooling device according to any one of claims 1 to 5, wherein the transition control means switches the ignition delay map when it is determined that the electric water pump has failed. An electric fan for cooling the internal combustion engine;
The cooling device according to any one of claims 1 to 6, wherein the transition control unit operates the electric fan when it is determined that the electric water pump is out of order. A cooling device for cooling the internal combustion engine in a vehicle including the internal combustion engine and an electric motor,
A circulation path through which a cooling medium for cooling the internal combustion engine flows;
An electric water pump for circulating the cooling medium;
Temperature measuring means for measuring the temperature of the cooling medium;
An air amount detecting means for detecting an air amount taken into the internal combustion engine;
Failure determination means for determining whether or not the electric water pump has failed; and
When it is determined that the electric water pump has failed, the temperature of the cooling medium measured when it is determined that the electric water pump has failed, and the accumulated value of the detected air amount Transition control means for shifting the operation mode of the vehicle to the fail-safe mode on condition that the difference from the temperature of the cooling medium measured when the temperature reaches a predetermined cumulative value is larger than the predetermined temperature difference. A cooling device characterized by.   9. The cooling apparatus according to claim 8, wherein the transition control unit includes a storage unit that stores the temperature of the cooling medium measured when it is determined that at least the electric water pump has failed. . The transition control means includes
Temperature difference determining means for determining whether the difference is greater than the predetermined temperature difference;
When it is determined that the difference is larger than the predetermined temperature difference, the operation mode is shifted to the fail safe mode, and when the difference is determined to be smaller than the predetermined temperature difference, the operation mode is changed to the fail safe mode. The cooling device according to claim 8 or 9, wherein the cooling device is not shifted to.

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