The present application claims priority from Japanese Patent Application No. 2016-218674 filed on Nov. 9, 2016, the entire contents of which are hereby incorporated by reference.
The technology relates to a cooling apparatus for vehicle that cools a heat-generating component.
A vehicle including an automobile is mounted with a heat-generating component such as an inverter, a converter, a motor-generator, and an engine. In order to cool the heat-generating component to a temperature within a predetermined temperature range, the vehicle is provided with a cooling system that cools the heat-generating component by circulating a coolant. To detect an abnormality of the cooling system, such as leakage of liquid from a pipe line, a radiator, or any other member of the cooling system, a device has been proposed that diagnoses presence of the abnormality on the basis of an increase in temperature of the coolant, by detecting an excessive increase in temperature of the coolant by means of a temperature sensor. For example, reference is made to Japanese Unexamined Patent Application Publication No. 2015-59458.
An abnormality of a cooling system is not limited only to leakage of liquid from a member such as a pipe line and a radiator. Possible examples of the abnormality may also include clogging of the member such as the pipe line and the radiator resulting from a foreign substance, freezing, or any other factor that may possibly cause the clogging. The clogging generated in the pipe line or any other member narrows a flow channel and thus decreases a circulation flow rate of a coolant. It has been, however, difficult to detect the decrease in the circulation flow rate at an early stage on the basis of an increase in temperature of the coolant.
It is desirable to provide a cooling apparatus for vehicle that is able to diagnose an abnormality of a cooling system at an early stage.
An aspect of the technology provides a cooling apparatus for vehicle. The apparatus includes: a cooling system that cools a heat-generating component by a coolant, and includes a cooling circuit in which the coolant circulates; a coolant pump that is provided in the cooling circuit, and causes the coolant to circulate in the cooling circuit; and a diagnostic controller that diagnoses an abnormality of the cooling system on a basis of a coolant temperature of the coolant that cools the heat-generating component. The diagnostic controller performs a first mode process and a second mode process. The first mode process increases the coolant temperature by stopping the coolant pump. The second mode process is performed after the first mode process is performed and causes the coolant temperature to fluctuate periodically by driving the coolant pump. The diagnostic controller, upon the second mode process, makes a diagnosis that the cooling system is normal on a condition that a cycle of the fluctuation of the coolant temperature is shorter than a reference time, and makes a diagnosis that the cooling system is abnormal on a condition that the cycle of the fluctuation of the coolant temperature is longer than the reference time.
[Configuration of Cooling Apparatus for Vehicle]
In the following, a description is given in detail of one implementation of the technology with reference to the accompanying drawings.
Referring to
The water pump 15 may be driven to suck the coolant from the reservoir tank 14 to the water pump 15 and feed the coolant from the water pump 15 to the radiator 16. The coolant having been cooled by traveling through the radiator 16 may be fed to the PCU 12 (i.e., to an unillustrated water jacket of the PCU 12) to cool the PCU 12, following which the coolant may be fed again to the reservoir tank 14. Thus, driving the water pump 15 allows the coolant to circulate along the cooling circuit 21 and thereby allows for continuous cooling of the PCU 12. For example, the water pump 15 may be an electric pump driven by an unillustrated electric motor.
The PCU 12 may electrically couple a motor-generator 22 and a battery 23 together, and may have built-in power conversion devices such as an inverter 24 and a converter 25. Upon a power-running operation of the motor-generator 22, a DC (direct current) current outputted from the battery 23 may be boosted by the converter 25, following which the boosted DC current may be converted into an AC (alternating current) current by the inverter 24. The thus-converted AC current may be supplied to the motor-generator 22 as a high-voltage AC current. Upon a regenerative operation of the motor-generator 22, an AC current outputted from the motor-generator 22 may be converted into a DC current by the inverter 24, following which the converted DC current may be stepped down by the converter 25. The thus-stepped-down DC current may be supplied to the battery 23 as a low-voltage DC current. The inverter 24 and the converter 25 each may include a switching device that generates heat upon conduction of electric power, such as an insulated-gate bipolar transistor (IGBT).
[Control System]
A description is now given of a control system of the cooling apparatus for vehicle 10.
The controller 30 may control a rotation speed of the water pump 15 on the basis of the coolant temperature Tp to thereby cause the coolant temperature Tp, equivalent to a temperature of the PCU 12, to fall within a predetermined temperature range. For example, the controller 30 may decrease the coolant temperature Tp by increasing the rotation speed of the water pump 15 and thereby increasing a circulation flow rate of the coolant in a case where the coolant temperature Tp is high. In a case where the coolant temperature Tp is low, the controller 30 may increase the coolant temperature Tp by decreasing the rotation speed of the water pump 15 and thereby decreasing the circulation flow rate of the coolant. The controller 30 also has a function of diagnosing an abnormality of the cooling system 13 as described later in greater detail. In one implementation, the controller 30 may serve as a “diagnostic controller”. The controller 30 may perform an abnormality diagnosing control upon traveling of the vehicle 11 during which the PCU 12 generates heat.
[Abnormality Diagnosing Control]
A description is given next of the abnormality diagnosing control that diagnoses the abnormality of the cooling system 13 according to one implementation.
Referring to
When the determination is made in step S12 that the coolant temperature Tp is equal to or less than the start threshold X0 (step S12: Y), the flow may proceed to step S13. In step S13, a first threshold X1, a second threshold X2, and a third threshold X3 may be set on the basis of the coolant temperature Tp. In other words, the first threshold X1, the second threshold X2, and the third threshold X3 may be set on the basis of the coolant temperature Tp that is before a later-described first mode process is started. As denoted by a reference sign a in
Referring back to
When the coolant temperature Tp falls below the start threshold X0 upon the start of the first mode process as described above, the first mode process may be started to continue the diagnosis of the cooling system 13 (S12 to S14). In contrast, when the coolant temperature Tp is greater than the start threshold X0 upon the start of the first mode process, the first mode process may be cancelled to discontinue the diagnosis of the cooling system 13 (S12 to S11).
The flow may proceed to step S15 after the first mode process is started in step S14. In step S15, a determination may be made as to whether a time during which the water pump 15 is stopped, i.e., a stopped time, is equal to or less than a predetermined permissible time t0. When the determination is made in step S15 that the stopped time of the water pump 15 is equal to or less than the permissible time t0 (step S15: Y), the flow may proceed to step S16. In step S16, a determination may be made as to whether the coolant temperature Tp is equal to or greater than the first threshold X1. When the determination is made in step S16 that the coolant temperature Tp is less than the first threshold X1 (step S16: N), the flow may proceed back to step S15 to determine whether the stopped time of the water pump 15 is equal to or less than the permissible time t0. The permissible time t0 may refer to a time period during which the coolant temperature Tp does not increase excessively even when the circulation of the coolant is stopped from a viewpoint of proper functioning of the PCU 12, and may be set on the basis of experiment, simulation, or any other factor.
When the determination is made in step S15 that the stopped time of the water pump 15 is greater than the permissible time t0 (step S15: N), the flow may proceed to step S17. In step S17, the water pump 15 may be switched to an operating state to discontinue the first mode process and to end the routine without making the abnormality diagnosis of the cooling system 13. In other words, a situation in which the stopped time of the water pump 15 is greater than the permissible time t0 in step S15 is where the coolant temperature Tp does not exceed the first threshold X1 within the permissible time t0 (denoted by a reference sign b1), as denoted by the dashed line L2 of
Referring back to
When the coolant temperature Tp is exceeds the first threshold X1 upon making the transition from the first mode process to the second mode process as described above, the transition is made to the second mode process to continue the diagnosis of the cooling system 13 (S16 to S18). In contrast, when the coolant temperature Tp is less than the first threshold X1 upon making the transition from the first mode process to the second mode process, making of the transition to the second mode process may be cancelled to discontinue the diagnosis of the cooling system 13 (S16 to S15, S15 to S17, and S17 to S11).
Referring to
When the coolant temperature Tp exceeds the first threshold X1 upon making the transition from the first mode process to the second mode process as described above, the transition is made to the second mode process to continue the diagnosis of the cooling system 13 (S16 to S18). In contrast, when the coolant temperature Tp is less than the first threshold X1 upon making the transition from the first mode process to the second mode process, making of the transition to the second mode process may be cancelled to discontinue the diagnosis of the cooling system 13 (S16 to S15, S15 to S17, and S17 to S11).
Referring back to
When the determination is made in step S22 that the operating time of the water pump 15 is greater than the reference time t1 (step S22: N), the flow may proceed to step S24. In step S24, information on attention may be displayed on the display 32 to the occupant, due to a possibility that the cooling circuit 21 is on the clogging side. In other words, a situation in which the operating time of the water pump 15 is greater than the reference time t1 in step S22 is where the coolant temperature Tp falls below the second threshold X2 within the reference time t1 (denoted by a reference sign e1) but does not exceed the third threshold X3 within the reference time t1 (denoted by a reference sign e2), as denoted by the dashed line L5 of
When the determination is made in step S23 that the coolant temperature Tp is equal to or greater than the third threshold X3 (step S23: Y), the flow may proceed to step S25. In step S25, the controller 30 may make a diagnosis that the cooling system 13 is normal, and may end the routine. In other words, a situation in which the coolant temperature Tp is equal to or greater than the third threshold X3 in step S23 is where, until the reference time t1 elapses from the start of the second mode process, the coolant temperature Tp falls below the second threshold X2 (denoted by a reference sign a2) and thereafter exceeds the third threshold X3 (denoted by a reference sign a3), as denoted by the solid line L1 of
The controller 30 according to one implementation described above thus performs the first mode process that increases the coolant temperature Tp by stopping the water pump 15, and thereafter performs the second mode process that cause the coolant temperature Tp to fluctuate periodically by driving the water pump 15, upon the abnormality diagnosing control of the cooling system 13. Further, upon the second mode process, the controller 30 makes the diagnosis that the cooling system 13 is normal when the fluctuation cycle Tc of the coolant temperature Tp is shorter than the reference time t1 in consideration of the sufficient circulation flow rate of the coolant, and makes the diagnosis that the cooling system 13 is abnormal when the fluctuation cycle Tc of the coolant temperature Tp is longer than the reference time t1 in consideration of the insufficient circulation flow rate of the coolant.
According to one implementation described above, the abnormality of the cooling system 13 is detected on the basis of the fluctuation cycle Tc of the coolant temperature Tp, instead of detecting the abnormality of the cooling system 13 on the basis of an excessive increase in the coolant temperature Tp. Hence, it is possible to diagnose the abnormality of the cooling system 13 at an early stage, and to increase reliability of the cooling system 13 accordingly. Further, the abnormality of the cooling system 13 is detected on the basis of the fluctuation cycle Tc of the coolant temperature Tp, making it possible to perform the abnormality diagnosing control with an extremely simple configuration. Hence, it is possible to restrain costs of the cooling apparatus for vehicle 10.
It is to be noted that
[Other Implementations]
In one implementation described above, the coolant temperature Tp of the PCU 12 is compared with the a threshold such as the second threshold X2 and the third threshold X3 to determine whether the fluctuation cycle Tc of the coolant temperature Tp is shorter than the reference time t1. A method on which the determination on the fluctuation cycle Tc of the coolant temperature Tp is based, however, is not limited thereto. In one implementation, the fluctuation cycle Tc of the coolant temperature Tp may be based on any other method.
Referring to
Referring to
When the determination is made in step S101 that the operating time of the water pump 15 is greater than the reference time t1 (step S101: N), the flow may proceed to step S21. In step S21, the information on the abnormality of the cooling system 13 may be displayed on the display 32 to the occupant, due to the possibility of clogging of the cooling circuit 21. In other words, a situation in which the operating time of the water pump 15 is greater than the reference time t1 in step S101 is where the coolant temperature Tp does not start to decrease until the reference time t1 elapses from the start of the second mode process, as denoted by the dashed line L3 of
When the determination is made in step S102 that the differential value of the variation amount ΔTp is minus (step S102: Y), i.e., when the coolant temperature Tp has made a transition from increase to decrease, the flow may proceed to step S103. In step S103, a determination may be made as to whether the operating time of the water pump 15 is equal to or less than the reference time t1. When the determination is made in step S103 that the operating time of the water pump 15 is equal to or less than the reference time t1 (step S103: Y), the flow may proceed to step S104. In step S104, a determination may be made as to whether the differential value of the variation amount ΔTp of the coolant temperature Tp is plus. When the determination is made in step S104 that the differential value of the variation amount ΔTp is minus (step S104: N), i.e., when the coolant temperature Tp continues to decrease, the flow may proceed back to step S103 to determine whether the operating time of the water pump 15 is equal to or less than the reference time t1.
When the determination is made in step S103 that the operating time of the water pump 15 is greater than the reference time t1 (step S103: N), the flow may proceed to step S24. In step S24, the information on attention may be displayed on the display 32 to the occupant, due to the possibility that the cooling circuit 21 is on the clogging side. In other words, a situation in which the operating time of the water pump 15 is greater than the reference time t1 in step S103 is where the coolant temperature Tp does not make a transition from decrease to increase until the reference time t1 elapses from the start of the second mode process, as denoted by the dashed line L4 of
When the determination is made in step S104 that the differential value of the variation amount ΔTp is plus (step S104: Y), i.e., when the coolant temperature Tp has made the transition from decrease to increase, the flow may proceed to step S105. In step S105, a determination may be made as to whether the operating time of the water pump 15 is equal to or less than the reference time t1. When the determination is made in step S105 that the operating time of the water pump 15 is equal to or less than the reference time t1 (step S105: Y), the flow may proceed to step S106. In step S106, a determination may be made as to whether the differential value of the variation amount ΔTp of the coolant temperature Tp is minus. When the determination is made in step S106 that the differential value of the variation amount ΔTp is plus (step S106: N), i.e., when the coolant temperature Tp continues to increase, the flow may proceed back to step S105 to determine whether the operating time of the water pump 15 is equal to or less than the reference time t1.
When the determination is made in step S105 that the operating time of the water pump 15 is greater than the reference time t1 (step S105: N), the flow may proceed to step S24. In step S24, the information on attention may be displayed on the display 32 to the occupant, due to the possibility that the cooling circuit 21 is on the clogging side. In other words, a situation in which the operating time of the water pump 15 is greater than the reference time t1 in step S105 is where the coolant temperature Tp makes the transition from decrease to increase but thereafter does not make the transition from increase to decrease until the reference time t1 elapses from the start of the second mode process, as denoted by the dashed line L5 of
When the determination is made in step S106 that the differential value of the variation amount ΔTp is minus (step S106: Y), i.e., when the coolant temperature Tp has made the transition from increase to decrease, the flow may proceed to step S25. In step S25, the controller 30 may make the diagnosis that the cooling system 13 is normal, and may end the routine. In other words, a situation in which the coolant temperature Tp makes the transition from increase to decrease in step S106 is where, until the reference time t1 elapses from the start of the second mode process, the coolant temperature Tp makes the transition from decrease to increase (denoted by a reference sign a10) and thereafter makes the transition from increase to decrease (denoted by a reference sign a20), as denoted by the solid line L1 of
Although some implementations of the technology have been described in the foregoing with reference to the accompanying drawings, the technology is by no means limited to the implementations described above, and is variously modifiable without departing from the scope as defined by the appended claims. For example, the cooling apparatus for vehicle 10 is applied to the vehicle 11 as the hybrid vehicle in any of the foregoing implementations. The vehicle 11 to which the cooling apparatus for vehicle 10 is applied, however, is not limited thereto. The cooling apparatus for vehicle 10 may be applied to any vehicle 11 as long as the vehicle 11 includes the cooling system 13 that cools any heat-generating component. In addition, the PCU 12 that includes the inverter 24 and the converter 25 is given as an example of the heat-generating component in any of the foregoing implementations. The heat-generating component as a target to be cooled, however, is not limited thereto. Non-limiting examples of the heat-generating component as the cooling target may include the inverter 24 alone and the converter 25 alone. Non-limiting examples of the heat-generating component may also include an electric motor and an engine. Further, one heat-generating component is provided for the cooling system 13 in an illustrated implementation. The number of heat-generating components provided for the cooling system 13, however, is not limited thereto. In an alternative implementation, a plurality of heat-generating components may be provided for one cooling system 13.
Further, a temperature of the coolant itself that flows in the PCU 12 is detected as the coolant temperature Tp of the PCU 12 in any of the foregoing implementations. A temperature as a target to be detected, however, is not limited thereto. Any other temperature that allows for estimation of the temperature of the coolant that flows in the PCU 12 may be detected. In an alternative implementation, a temperature of a housing of the PCU 12 may be utilized as the coolant temperature Tp. In a further alternative implementation, a temperature of one or both of the inverter 24 and the converter 25 provided in the PCU 12 may be utilized as the coolant temperature Tp. In a yet further alternative implementation, a temperature of any of various devices that are provided in the inverter 24 and the converter 25 and generate heat, such as the switching device and a reactor, may be utilized as the coolant temperature Tp. Moreover, in one implementation described above, the variation amount ΔTp of the coolant temperature Tp is differentiated to determine the increase or the decrease of the coolant temperature Tp. A method of determining the increase or the decrease of the coolant temperature Tp, however, is not limited thereto. In an alternative implementation, the increase or the decrease of the variation amount ΔTp may be calculated for each predetermined time t0 determine the increase or the decrease of the coolant temperature Tp.
The controller 30 illustrated in
It should be appreciated that modifications and alterations may be made by persons skilled in the art without departing from the scope as defined by the appended claims. The technology is intended to include such modifications and alterations in so far as they fall within the scope of the appended claims or the equivalents thereof.
Number | Date | Country | Kind |
---|---|---|---|
2016-218674 | Nov 2016 | JP | national |
Number | Name | Date | Kind |
---|---|---|---|
7398745 | White | Jul 2008 | B1 |
20020195068 | Ichinose | Dec 2002 | A1 |
20120085157 | Nishigaki | Apr 2012 | A1 |
20120330496 | Eser | Dec 2012 | A1 |
20130213600 | Saitoh | Aug 2013 | A1 |
20160258343 | Mushiga | Sep 2016 | A1 |
Number | Date | Country |
---|---|---|
H06-117259 | Apr 1994 | JP |
2008-215183 | Sep 2008 | JP |
2010-007569 | Jan 2010 | JP |
2015-059458 | Mar 2015 | JP |
Entry |
---|
Japanese Office Action dated Sep. 4, 2018 for JP Patent Application No. 2016-218674 (4 pages in Japanese with English translation). |
Number | Date | Country | |
---|---|---|---|
20180128155 A1 | May 2018 | US |