JP2016151218A - Cooling device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure heater performance to the utmost while suppressing overheat, when abnormality occurs in a control valve.SOLUTION: A cooling device for an internal combustion engine includes a cooling water circuit 18 having a radiator circuit 20, a heater circuit 22, and a device circuit 24. The device further includes a rotary selector valve 42 capable of changing the routing of cooling water selectively among the plurality of circuits of the cooling water circuit 18, and also continuously changing the flow amount of the cooing water in the individual circuits. Under the condition that the rotating angle of a rotor with the opening of the heater circuit 22 being not smaller than 30% is in an abnormal site, if there is a heater request, the state of controlling the rotary selector valve 42 is changed depending on whether the temperature of the cooling water is lower or not lower than 70°C. Under the condition that the rotating angle of the rotor with the opening of the heater circuit 22 being smaller than 30% but not smaller than 15% is in the abnormal site, if there is the heater request, the state of controlling the rotor selector valve 42 is changed on the basis of the temperature of outside air in addition to the temperature of the cooling water.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a cooling device for an internal combustion engine.

  Patent Document 1 discloses a cooling device for an internal combustion engine. This cooling device allows or blocks the flow of cooling water between a heater circulation path in which a heater core and a water pump for air conditioning in a vehicle are installed, and between a water jacket of an engine and a heater circulation path. Two or more valves. In order to avoid overheating or overcooling of the engine after coping with the closing failure, when any of the valves that are requested to open is in a closed state, the other valves are opened. The lower limit value or upper limit value of the engine output is limited according to the opened valve.

JP 2013-024188 A

  By the way, as a plurality of circuits through which the cooling water circulates through the main body of the internal combustion engine, a radiator circuit through which the cooling water passes through a radiator that releases heat of the cooling water, and a heater through which the cooling water passes through a heater core for vehicle interior air conditioning And a control valve capable of selecting a path configuration in which the cooling water circulates only in one of the radiator circuit and the heater circuit and a path configuration in which the cooling water circulates in both of them. Conceivable. Even when such a configuration is adopted, a measure for suppressing overheating caused by an abnormality of the control valve is necessary. Further, the degree of required heater performance for vehicle window glass de-ice and vehicle interior heating varies depending on the outside air temperature. Therefore, it is desirable that the countermeasure when an abnormality occurs in the control valve is to ensure the heater performance as much as possible while suppressing the overheating.

  The present invention has been made to solve the above-described problems, and it is an object of the present invention to provide a cooling device for an internal combustion engine capable of suppressing heater overheating and ensuring heater performance as much as possible when a control valve abnormality occurs. And

  The cooling device for an internal combustion engine according to the present invention includes a cooling water circuit, a control valve, a drive unit, and an abnormal point detection unit. The cooling water circuit is a plurality of circuits through which the cooling water circulates through the main body of the internal combustion engine, a radiator circuit through which the cooling water passes through a radiator that releases heat of the cooling water, and a vehicle equipped with the internal combustion engine. And at least a heater circuit through which the cooling water passes through a heater core for air conditioning in a vehicle interior. The control valve can change the path of the cooling water from among the plurality of circuits, and can continuously change the flow rate of the cooling water in individual circuits of the plurality of circuits. The driving means displaces the control valve within a predetermined movable range. The abnormal part detection means detects an abnormal part of the control valve within the movable range when the internal combustion engine is started. The movable range includes at least a first range, a second range, a third range, and a fourth range. In the first range, both the radiator circuit and the heater circuit are closed by the control valve. The second range is a range obtained in a state where the control valve is displaced in a specific direction beyond the first range, and in the second range, the radiator among the radiator circuit and the heater circuit. The circuit is opened. The third range is a range obtained in a state in which the control valve is displaced in the direction opposite to the specific direction beyond the first range, and in the third range, the radiator circuit and the heater circuit The heater circuit is opened at home. The fourth range is a range obtained by further displacing the control valve in the opposite direction beyond the third range, and in the fourth range, both the radiator circuit and the heater circuit are Opened. In the third range or the fourth range, the driving means may be configured such that the control position of the control valve when the opening degree of the heater circuit is greater than or equal to a first predetermined opening degree is the abnormal position. When there is a heater request for circulating the cooling water in the circuit, the control position of the control valve is changed depending on whether the temperature of the cooling water is equal to or higher than a predetermined temperature. In the third range, the driving means is configured such that the control position of the control valve when the opening degree of the heater circuit is greater than or equal to a second predetermined opening degree and less than the first predetermined opening degree is the abnormal position. Under such circumstances, if there is a heater request, the control position of the control valve is changed based on the outside air temperature in addition to the temperature of the cooling water.

  According to the present invention, when an abnormal portion of the control valve is recognized in the third range or the fourth range where the heater circuit is opened, the control position of the control valve is determined in consideration of the cooling water temperature and the outside air temperature. Be changed. As a result, when the control valve malfunctions, overheat can be suppressed and heater performance can be ensured as much as possible.

It is a figure for demonstrating the system configuration | structure of an internal combustion engine provided with the cooling device which concerns on Embodiment 1 of this invention. It is a figure for demonstrating the basic operation | movement of the rotary switching valve shown in FIG. It is a figure for demonstrating an example of the detection method of the abnormal location of the rotor used for the abnormal location learning in Embodiment 1 of this invention. It is a flowchart which shows the flow of the fail safe control in Embodiment 1 of this invention. It is a figure for demonstrating control of the rotary switching valve when abnormality generate | occur | produces in the rotary switching valve within the range B shown in FIG. It is a figure for demonstrating another example of the detection method of the abnormal location of the rotor which can be used for the abnormal location learning in Embodiment 1 of this invention.

Embodiment 1 FIG.
[Configuration of Embodiment 1]
FIG. 1 is a diagram for explaining a system configuration of an internal combustion engine 10 provided with a cooling device according to Embodiment 1 of the present invention. It is assumed that the internal combustion engine 10 shown in FIG. 1 is mounted on a vehicle and used as a power source. In the cylinder block 12 and the cylinder head 14 corresponding to the main body of the internal combustion engine 10, a water jacket 16 through which cooling water for cooling the main body flows is formed. The water jacket 16 is one of the components of the cooling water circuit 18 that circulates the cooling water through the main body of the internal combustion engine 10. Heat exchange is performed between the cooling water flowing through the water jacket 16 and the cylinder block 12 and the cylinder head 14.

  The cooling water circuit 18 includes three circuits, more specifically, a radiator circuit 20, a heater circuit 22, and a device circuit 24. The radiator circuit 20 is a circuit that passes through the water jacket 16 and the radiator 26 that releases heat of the cooling water. According to the radiator circuit 20, heat exchange is performed between the cooling water flowing through the radiator 26 and the outside air.

  The heater circuit 22 is a circuit through which the cooling water passes through the water jacket 16 and the heater core 28 for air conditioning the vehicle interior of the vehicle. According to the heater circuit 22, heat exchange is performed between the cooling water flowing through the heater core 28 and the cabin air. The device circuit 24 is a circuit through which cooling water passes through various devices included in the internal combustion engine 10 together with the water jacket 16. In this embodiment, the device to be cooled corresponds to the EGR cooler 30, the automatic transmission oil cooler 32, and the engine oil cooler 34. When cooling water is circulated through these devices, heat exchange is performed between the fluid (EGR gas or oil) flowing through the devices and the cooling water.

  The radiator circuit 20, the heater circuit 22, and the device circuit 24 merge near the cooling water inlet to the water jacket 16. A water pump 36 for pumping the cooling water is provided at the junction. The water pump 36 is an electric type.

  The inlet of the water jacket 16 and the discharge port of the water pump 36 are connected via an inlet-side common flow path 38. The outlet of the water jacket 16 is connected to the rotary switching valve 42 via the outlet-side common flow path 40. The rotary switching valve 42 is provided at a portion where the flow path branches from the outlet-side common flow path 40 toward the unique flow paths of the radiator circuit 20, the heater circuit 22, and the device circuit 24.

  The rotary switching valve 42 is an electric valve. More specifically, the valve body of the rotary switching valve 42 includes a cooling water inflow port 42a and three cooling water discharge ports 42b to 42d. The discharge ports 42b to 42d are connected to the radiator circuit 20, the heater circuit 22, and the device circuit 24, respectively. A rotor (not shown) is rotatably arranged inside the valve body. The rotor is rotationally driven by an electric motor 44. The rotor is configured such that the ratio of the opening area of each of the discharge ports 42b to 42d to the opening area of the inflow port 42a can be changed according to the rotational position. Thus, although details will be described later with reference to FIG. 2, according to the rotary switching valve 42, the radiator circuit 20, the heater circuit 22, and the device are adjusted by adjusting the rotation angle (rotation position) of the rotor by the electric motor 44. The flow rate of the cooling water flowing through each of the circuits 24 can be changed.

  The rotary switching valve 42 is attached with a position sensor 46 for detecting the rotation angle (rotation position) of the rotor. Furthermore, a water temperature sensor 48 for detecting the temperature of the cooling water (more specifically, the temperature of the cooling water immediately after flowing out of the water jacket 16) is attached to the outlet-side common flow path 40.

  Further, the system shown in FIG. 1 includes an ECU (Electronic Control Unit) 50. The ECU 50 includes an arithmetic processing unit (CPU), a storage circuit including a ROM and a RAM, an input / output port, and the like. Various sensors for detecting the operating state of the internal combustion engine 10 such as the position sensor 46 and the water temperature sensor 48 described above are electrically connected to the input port of the ECU 50. Various actuators for controlling the operation of the internal combustion engine 10 such as the water pump 36 and the electric motor 44 described above are electrically connected to the output port of the ECU 50. Furthermore, an external air temperature sensor 52 that detects the external air temperature, and an ignition switch (IG switch) 54 for the vehicle driver to start and stop the vehicle system are electrically connected to the input port of the ECU 50. In addition, a fan motor 56 for air conditioning the vehicle interior and a MIL (Malfunction Indication Lamp) 58 are electrically connected to the output port of the ECU 50. The storage circuit stores a control program that defines an opening schedule, which will be described later, various maps, and the like. The CPU reads out and executes a control program or the like from the memory, and generates an operation signal based on the acquired sensor signal.

[Control of Embodiment 1]
(Basic operation of rotary switching valve)
FIG. 2 is a view for explaining the basic operation of the rotary switching valve 42 shown in FIG. The “movable range of the rotor” shown in FIG. 2 is a control range of the rotation angle (rotation position) of the rotor driven by the electric motor 44. More specifically, the rotor is driven by the electric motor 44 so as to reciprocate within the movable range.

  The rotary switching valve 42 can change the path of the cooling water flowing out of the water jacket 16 from the radiator circuit 20, the heater circuit 22, and the device circuit 24 by adjusting the rotation angle of the rotor within the movable range. In addition, the flow rate of the cooling water flowing through these individual circuits can be continuously changed.

  FIG. 2 shows various path forms of cooling water realized by the rotary switching valve 42. As the control mode of the rotary switching valve 42, the ECU 50 uses a “heater flow mode” that uses the range A to D of the movable range of the rotor and a “heater cut mode” that uses the range A, range E, or range F. ". The boundary between the heater water flow mode and the heater cut mode is within the range A. In range A, all three circuits are closed by the rotary switching valve 42. Therefore, the range A is used in a state where the driving of the water pump 36 is stopped.

  The heater water flow mode is used when there is a request for allowing the coolant water to pass through the heater core 28 (hereinafter referred to as “heater request”). In the heater water supply mode, the priority is given to the flow of the cooling water to the heater core 28. In FIG. 2, when the rotor is rotated in the direction proceeding to the right from the range A (corresponding to the “opposite direction of the specific direction” in the present invention), the rotation angle of the rotor shifts to the range B adjacent to the range A. When reaching the range B from the range A side, the inflow port 42a and the heater outflow port 42c begin to communicate (that is, the heater circuit 22 begins to open). As a result, the cooling water starts to circulate in the heater circuit 22. If the rotation of the rotor is further continued from this state, the opening degree of the heater circuit 22 continuously increases toward the maximum opening degree (100%) in accordance with an increase in the rotation amount of the rotor. For this reason, by continuously adjusting the opening degree of the heater circuit 22 in the range B, the flow rate of the cooling water flowing through the heater circuit 22 can be continuously adjusted.

  When the rotation of the rotor is further advanced from the state where the opening degree of the heater circuit 22 reaches the maximum opening degree, the rotation angle of the rotor shifts to a range C adjacent to the range B. When reaching the range C from the range B side, the device circuit 24 starts to open while the opening degree of the heater circuit 22 is maintained at the maximum opening degree. In the range C, the larger the rotation amount of the rotor in the direction to the right in the range C in FIG. 2, the larger the opening degree of the device circuit 24 while the opening degree of the heater circuit 22 is maintained at the maximum opening degree. It continuously increases toward the degree (100%). For this reason, by continuously adjusting the opening degree of the device circuit 24 in the range C, the flow rate of the cooling water flowing through the device circuit 24 can be continuously adjusted.

  When the rotation of the rotor is further advanced from the state where the opening degree of the device circuit 24 reaches the maximum opening degree, the rotation angle of the rotor shifts to a range D adjacent to the range C. When reaching the range D from the range C side, the radiator circuit 20 starts to open with the opening degree of the heater circuit 22 and the device circuit 24 maintained at the maximum opening degree. In the range D, the opening of the radiator circuit 20 is maintained in a state where the opening degree of the heater circuit 22 and the device circuit 24 is maintained at the maximum opening degree as the rotation amount of the rotor in the direction proceeding to the right in the range D in FIG. The degree increases continuously toward the maximum opening (100%). For this reason, by continuously adjusting the opening degree of the radiator circuit 20 in the range D, the flow rate of the cooling water flowing through the radiator circuit 20 can be continuously adjusted.

  On the other hand, the heater cut mode is used when there is no heater request. In the heater cut mode, cooling water is not supplied to the heater core 28, and the cooling water is supplied to the devices such as the EGR cooler 30 in preference to the radiator 26. Therefore, in the heater cut mode, water passing through the device is given the highest priority.

  In FIG. 2, when the rotor is rotated in the direction proceeding to the left from the range A (corresponding to the “specific direction” in the present invention), the rotation angle of the rotor shifts to the range E adjacent to the range A. When reaching the range E from the range A side, the inflow port 42a and the outflow port 42d for devices begin to communicate (that is, the device circuit 24 begins to open). As a result, the cooling water starts to circulate in the device circuit 24. When the rotation of the rotor is further continued from this state, the opening degree of the device circuit 24 continuously increases toward the maximum opening degree (100%) as the amount of rotation of the rotor increases. In the range E, a range in which the opening degree of the device circuit 24 is maintained at the maximum opening degree is also provided. Thus, by continuously adjusting the opening degree of the device circuit 24 in the range E, the flow rate of the cooling water flowing through the device circuit 24 can be continuously adjusted.

  In FIG. 2, when the rotor is further rotated to the left from the range E, the rotation angle of the rotor shifts to a range F adjacent to the range E. When reaching the range F from the range E side, the radiator circuit 20 starts to open while the opening degree of the device circuit 24 is maintained at the maximum opening degree. In the range F, the larger the rotor rotation amount in the direction to the left in the range F in FIG. It continuously increases toward the degree (100%). For this reason, by continuously adjusting the opening degree of the radiator circuit 20 in the range F, the flow rate of the cooling water flowing through the radiator circuit 20 can be continuously adjusted.

  According to the above control of the rotation angle of the rotary switching valve 42, it becomes possible to change the path configuration of the cooling water with a high degree of freedom according to the opening schedule shown in FIG. Thereby, while ensuring the cooling performance of the cooling water by the radiator 26, it becomes possible to warm up / cool various devices with a higher degree of freedom and to draw out the heater performance more appropriately.

(Fail-safe control of rotary switching valve)
By the way, it is assumed that an abnormality occurs in the rotary switching valve 42 described above in such a manner that the rotation of the rotor near a specific rotation angle cannot be smoothly performed. If the cooling water cannot be supplied to the radiator circuit 20 due to the occurrence of such an abnormality, the internal combustion engine 10 may be overheated. For this reason, the countermeasure for suppressing the overheating resulting from abnormality of the rotary switching valve 42 is required. Further, the degree of required heater performance for vehicle window glass de-ice and vehicle interior heating varies depending on the outside air temperature. Therefore, it is desirable that a countermeasure when an abnormality occurs in the rotary switching valve 42 is to ensure the heater performance as much as possible while suppressing overheating.

  Therefore, in the present embodiment, the following “abnormal part learning” is performed in the IG switch ON state (that is, the engine start request is issued) before the start of the engine start operation. Specifically, a portion where an abnormality is recognized in the rotational operation of the rotor using the position sensor 46 and the drive current value of the electric motor 44 while operating the rotor from end to end within the movable range shown in FIG. It was decided whether or not there was (rotation angle). And when such abnormality is recognized, it decided to identify an abnormal location and memorize | store it in ECU50.

  FIG. 3 is a diagram for explaining an example of a method for detecting an abnormal part of the rotor used for abnormal part learning according to the first embodiment of the present invention. FIG. 3 is a diagram showing the relationship between the drive current value of the electric motor 44 and the detected value of the position sensor 46 (that is, the rotation angle of the rotor). When the rotor is rotated within the movable range, if there is resistance to the movement of the rotor at a specific part (rotation angle) for some reason, the current value increases as shown as “abnormal value” in FIG. To do. Therefore, by determining in advance the threshold value α of the current value with which the occurrence of abnormality can be determined, the rotation angle of the rotor where the current value (abnormal value) exceeding the threshold value α is detected can be specified as the abnormal part. .

  In the present embodiment, the following fail-safe control is performed using the fact that the abnormal part can be identified by the abnormal part learning. That is, there is a concern that if the use of the part is continued in a state where the operation of the rotary switching valve 42 is abnormal at a certain part, the rotary switching valve 42 is stuck and does not operate during use of the part. The If such a situation occurs at a rotation angle at which the opening of the radiator circuit 20 is not sufficient, there is a high possibility of causing a major failure such as overheating.

  Therefore, in the present embodiment, when an abnormal location is specified at the time of occurrence of an abnormality, the rotation angle range up to the front of the abnormal location is set as a use range, and the heater water flow mode or the heater cut including the abnormal location is used. The use of the mode was restricted. In addition, even when such an overheat countermeasure is taken, in order to ensure the heater performance as much as possible, more specifically, the control according to the flowchart shown in FIG. 4 is performed.

  FIG. 4 is a flowchart showing a flow of fail-safe control in the first embodiment of the present invention. In the process of the flowchart shown in FIG. 4, first, in step 100, the ECU 50 performs the above-described abnormal part learning at the time of the current engine start (more specifically, the IG switch ON state before the start of the engine start operation). For this purpose, the rotor is rotated from end to end of the movable range shown in FIG.

  Next, in step 102, the ECU 50 determines whether or not the peak current value of the electric motor 44 during the rotating operation of the rotor in step 100 is equal to or greater than the threshold value α. As a result, if this determination is not satisfied, that is, if it can be determined that no abnormality has occurred in the rotary switching valve 42, the ECU 50 proceeds to step 104. In step 104, the normal operation of the rotary switching valve 42 (that is, a predetermined operation for controlling the path form of the cooling water according to the heater request and various device requests using the opening schedule shown in FIG. 2) is executed.

  On the other hand, if the determination in step 102 is satisfied, that is, if it can be determined that an abnormality has occurred in the rotary switching valve 42, the ECU 50 proceeds to step 106. In step 106, the position sensor 46 is used to identify an abnormal part (rotation angle of the rotor showing an abnormal value) by the method described with reference to FIG.

  Next, the ECU 50 proceeds to step 108, and determines whether or not the specified abnormal portion is the rotation angle of the rotor when the opening degree of the radiator circuit 20 is 50% or more. As a result, when this determination is established, the ECU 50 proceeds to step 110. The rotation angle of the rotor when the opening degree of the radiator circuit 20 is 50% or more belongs to the range D or the range F. These ranges are ranges in which the temperature of the cooling water needs to be adjusted by the radiator 26. However, if the opening degree of the radiator circuit 20 can be secured about 50%, the flow rate of the cooling water circulating through the radiator circuit 20 is as follows. Can secure a flow rate of about 80% of the required flow rate. If the flow rate is about 80%, it can be said that normal operation is possible except for extreme use conditions. Therefore, in this case, the ECU 50 proceeds to step 110 without turning on the MIL 58. In step 110, normal operation is performed when using the control mode which does not have an abnormal part among heater flowing mode and heater cut mode. Further, when using the control mode having the abnormal portion, the rotation angle range in which the opening degree of the radiator circuit 20 is less than 50% (one of the ranges A to C and the range D in the heater water flow mode). If the part corresponds to the heater cut mode, the rotary switching valve 42 is controlled within the ranges A, E, and part of the range F). In addition, although the cooling performance is slightly limited by performing such control, if extreme high load operation is performed and the cooling water temperature becomes high, control normally performed to avoid overheating. As with, overheating can be avoided by limiting the engine output. More specifically, since the flow rate of 80% or more can be secured as described above, such an output limit is an extremely high load operation in which the vehicle travels uphill while towing another vehicle. Limited to time.

  On the other hand, if the determination in step 108 is not established, that is, if the specified abnormal location is the rotation angle of the rotor when the opening of the radiator circuit 20 is less than 50%, the ECU 50 proceeds to step 112. The MIL 58 is turned on to notify the vehicle driver of the current abnormality related to the rotary switching valve 42.

  Next, the ECU 50 proceeds to step 114 and determines whether or not the specified abnormal location is in the heater water flow mode. As a result, when this determination is not satisfied, that is, when the specified abnormal portion is in the heater cut mode, the ECU 50 proceeds to step 116. In step 116, it is determined whether or not there is a heater request. The presence or absence of a heater request can be determined by, for example, the ECU 50 detecting a signal from an air conditioning switch (not shown) in the passenger compartment.

  If the determination in step 116 is true, that is, if there is a heater request when abnormality is recognized in the heater cut mode, the ECU 50 proceeds to step 118. In step 118, the normal operation of the rotary switching valve 42 is executed using the heater water flow mode having no abnormal part. On the other hand, if the determination in step 116 is not established, that is, if there is no heater request when an abnormality is recognized in the heater cut mode, the ECU 50 proceeds to step 120. In this case, since there is no heater request, the heater cut mode should be used. However, in order to avoid the use of the heater cut mode having an abnormal part from the viewpoint of fail-safe, in step 120, the rotary switching valve 42 is controlled so that the heater water flow mode is used.

  On the other hand, if the determination in step 114 is established, that is, if the specified abnormal location is in the heater water-passing mode, the ECU 50 proceeds to step 122 and determines whether there is a heater request. As a result, if there is no heater request, the ECU 50 proceeds to step 124. In step 124, the normal operation of the rotary switching valve 42 is executed using a heater cut mode that does not have an abnormal point.

  If it is determined in step 122 that there is a heater request, the ECU 50 proceeds to step 126. In step 126, it is determined whether or not the identified abnormal location is the rotation angle of the rotor when the opening degree of the heater circuit 22 is equal to or greater than the first predetermined opening degree. If the opening degree of the heater circuit 22 can be secured about 30%, it is considered that the heater performance (in-vehicle heating or de-ice) can be secured. Therefore, the first predetermined opening degree can secure such a heater performance. This value is set in advance so that the lower limit of the opening range of the heater circuit 22 can be determined (here, 30% as an example).

  If the determination in step 126 is true, the ECU 50 proceeds to step 128. In step 128, it is determined whether or not the cooling water temperature detected by the water temperature sensor 48 is equal to or lower than a first predetermined temperature. The first predetermined temperature is a value set in advance so as to be able to determine the upper limit of the cooling water temperature range in which it is not necessary to cool the cooling water using the radiator circuit 20 (here, 70 ° C. as an example). It is.

  If it is determined in step 128 that the coolant temperature is equal to or lower than the first predetermined temperature, the ECU 50 proceeds to step 130. The case where the determination in step 126 and the determination in step 128 are continuously established is a case where it can be determined that the heater performance can be ensured, and it is not necessary to cool the cooling water using the radiator circuit 20. Therefore, in such a case, although there is an abnormal part in the heater water flow mode, in order to ensure the heater performance as much as possible, the radiator circuit 20 is finally used for cooling. It can be said that it is preferable to use the heater circuit 22 within the usable opening range until the cooling water temperature rises to a certain extent to cool the water.

  For this reason, in step 130, the rotary switching valve 42 is controlled to use the heater water flow mode within the rotation angle range of the rotor that does not correspond to the abnormal part. FIG. 5 is a diagram for explaining the control of the rotary switching valve 42 when an abnormality occurs in the rotary switching valve 42 within the range B shown in FIG. The processing in step 130 corresponds to the operation shown in FIG. That is, when the cooling water temperature is equal to or lower than the first predetermined temperature (70 ° C.), only the heater circuit 22 of the three circuits is used under the restriction that the vicinity of the rotation angle of the rotor corresponding to the abnormal part is not used. In order to use the heater water flow mode in such a manner that the cooling water circulates, the rotary switching valve 42 is controlled.

  Next, the ECU 50 proceeds to step 132 and determines whether or not the coolant temperature is equal to or higher than a second predetermined temperature that is higher than the first predetermined temperature. This second predetermined temperature is a value set in advance (in this case, 80 ° C. as an example) in order to be able to determine the cooling water temperature that will eventually require the use of the radiator circuit 20 to avoid overheating. is there. While the determination at step 132 is not established, the process at step 130 is continued.

  On the other hand, if the determination in step 132 is established, that is, if the coolant temperature has increased to a level that requires the use of the radiator circuit 20, the ECU 50 proceeds to step 134. In step 134, the air conditioning fan is stopped by stopping energization of the fan motor 56. Next, the ECU 50 proceeds to step 136, and the rotary switching valve 42 controls the control mode to transition to the heater cut mode in order to ensure engine cooling performance (avoid overheating). More specifically, the range F is used because it is a situation where the radiator circuit 20 needs to be used. The process of step 136 corresponds to the operation shown in FIG. That is, by using the range F, the rotary switching valve 42 is controlled so that the cooling water is circulated in the radiator circuit 20 together with the device circuit 24 without circulating the cooling water in the heater circuit 22.

  On the other hand, if the determination in step 128 is not satisfied, that is, if the coolant temperature has already exceeded the first predetermined temperature at the stage where the determination in step 128 is performed, the ECU 50 proceeds to step 138. In this case, since there is a heater request, it is a situation where the heater water flow mode is desired. However, here, since the cooling water temperature is reasonably high, priority is given to avoiding overheating, and in order to avoid the use of the heater water passing mode having an abnormal location from the viewpoint of fail-safe, in step 138, the heater cut mode is used. Thus, the rotary switching valve 42 is controlled.

  If the determination in step 126 is not established, the ECU 50 proceeds to step 140. In step 140, it is determined whether or not the specified abnormal location is the rotation angle of the rotor when the opening degree of the heater circuit 22 is less than the first predetermined opening degree and is equal to or larger than the second predetermined opening degree. When the outside air temperature is equal to or lower than a predetermined temperature (for example, 5 ° C.), the demand for window glass de-ice and vehicle interior heating is further increased. If the outside air temperature is thus low, the temperature difference between the outside air temperature and the cooling water temperature becomes large even if the opening degree of the heater circuit 22 is about 15%. For this reason, it becomes easy to ensure the heater performance even if the flow rate of the cooling water in the heater circuit 22 is small. The second predetermined opening is a value set in advance to enable the lower limit of the opening range of the heater circuit 22 to be said to be able to ensure the heater performance in a situation where the outside air temperature is equal to or lower than the predetermined temperature ( Here, as an example, 15%).

  If the determination in step 140 is not established, that is, if it can be determined that the heater performance cannot be ensured because the opening of the heater circuit 22 is less than the second predetermined opening, the ECU 50 proceeds to step 138. Use heater cut mode. On the other hand, when the determination in step 140 is established, the ECU 50 proceeds to step 142 and determines whether or not the outside air temperature is equal to or lower than a predetermined temperature. As described above, the predetermined temperature is set in advance as a threshold value of the outside air temperature (here, 5 ° C. as an example) at which the demand for heater performance is higher.

  If the determination in step 142 is not satisfied, that is, the second predetermined opening degree is secured, but the outside air temperature is higher than the predetermined temperature, so it is difficult to secure the heater performance with the current opening degree of the heater circuit 22. If it can be determined, the ECU 50 proceeds to step 138 and uses the heater cut mode. On the other hand, if the determination in step 142 is satisfied, that is, the opening degree of the heater circuit 22 is smaller than the first predetermined opening degree (30%), but the second predetermined opening degree (15%) can be secured, and the predetermined opening degree is satisfied. When there is a heater request under a situation where the temperature is low (5 ° C.) or lower, the ECU 50 executes the processing from step 128 onward. This is to satisfy as much as possible the demand for de-ice and vehicle interior heating that increase under low outside air temperatures.

  According to the fail-safe control of the present embodiment described above, the rotation angle of the rotor when the opening degree of the heater circuit 22 is equal to or greater than the first predetermined opening degree (30%) (range B to range on the heater water flow mode side) If there is a heater request in a situation where (in D) is an abnormal location, the control state of the rotary switching valve 42 depends on whether the coolant temperature is equal to or higher than the first predetermined temperature (70 ° C.). Be changed. The rotation angle of the rotor when the opening degree of the heater circuit 22 is less than the first predetermined opening degree (30%) and equal to or more than the second predetermined opening degree (15%) (in the range B on the heater water flow mode side). When there is a heater request in a situation where an abnormal position is present), the control state of the rotary switching valve 42 is changed based on the outside air temperature in addition to the cooling water temperature. According to such control, when there is a heater request in a situation where an abnormal portion is recognized in the heater water flow mode, the use of the heater water flow mode is not prohibited (uniformly) but the cooling water The rotary switching valve 42 is controlled in consideration of the temperature and further the outside air temperature. As a result, the heater circuit 22 can be used as much as possible while considering the overheating by considering the cooling water temperature (particularly under a low outside air temperature) with a restriction. For this reason, when the abnormality occurs in the rotary switching valve 42, it is possible to suppress the overheating and ensure the heater performance as much as possible.

(Another example of a method for detecting abnormal parts of the rotor)
FIG. 6 is a diagram for explaining another example of a method for detecting an abnormal part of a rotor that can be used for abnormal part learning in the first embodiment of the present invention. FIG. 6 is a diagram showing the relationship between the rotational speed of the rotor and the detected value of the position sensor 46 (that is, the rotational angle of the rotor). The rotational speed of the rotor can be calculated based on the rotational angle of the rotor detected by the position sensor 46. When the rotor is rotated within the movable range shown in FIG. 2, if there is resistance to the movement of the rotor at a specific part (rotation angle) for some reason, as shown as “abnormal value” in FIG. Rotor rotation speed becomes slow. Therefore, by determining in advance the threshold value β of the rotor rotational speed at which occurrence of abnormality can be determined, the rotational angle of the rotor in which the rotational speed (abnormal value) exceeding the threshold value β is detected is specified as the abnormal part. Can do.

  In the first embodiment described above, the rotary switching valve 42 is the “control valve” in the present invention, the range A is the “first range” in the present invention, and the range F is the “second range” in the present invention. , Range B and range C are the “third range” in the present invention, range D is the “fourth range” in the present invention, and the first predetermined temperature (70 ° C.) of the cooling water temperature is the “predetermined temperature” in the present invention. Respectively. Further, the “drive means” in the present invention is realized by the ECU 50 controlling the rotary switching valve 42 according to the flowchart shown in FIG. 4, and the ECU 50 executes the processing of Steps 100, 102 and 104. The “abnormal part detecting means” in the invention is realized.

DESCRIPTION OF SYMBOLS 10 Internal combustion engine 12 Cylinder block 14 Cylinder head 16 Water jacket 18 Cooling water circuit 20 Radiator circuit 22 Heater circuit 24 Device circuit 26 Radiator 28 Heater core 30 EGR cooler 32 Automatic transmission oil cooler 34 Engine oil cooler 36 Water pump 38 Inlet side common flow Path 40 Outlet side common flow path 42 Rotary switching valve 42a Inflow ports 42b, 42c, 42d Outflow port 44 Electric motor 46 Position sensor 48 Water temperature sensor 50 ECU (Electronic Control Unit)
52 Outside temperature sensor 54 Ignition switch (IG switch)
56 Fan motor 58 MIL (Malfunction Indication Lamp)

Claims (1)

As a plurality of circuits through which cooling water circulates through the main body of the internal combustion engine, a radiator circuit through which the cooling water passes through a radiator that releases heat of the cooling water, and a vehicle interior air conditioner for a vehicle in which the internal combustion engine is mounted A cooling water circuit including at least a heater circuit through which the cooling water passes through a heater core;
A control valve capable of changing a path of the cooling water from among the plurality of circuits and continuously changing a flow rate of the cooling water in each of the plurality of circuits;
Driving means for displacing the control valve within a predetermined movable range;
An abnormal point detecting means for detecting an abnormal point of the control valve within the movable range at the time of starting the internal combustion engine;
With
The movable range includes at least a first range, a second range, a third range, and a fourth range,
In the first range, both the radiator circuit and the heater circuit are closed by the control valve,
The second range is a range obtained in a state where the control valve is displaced in a specific direction beyond the first range, and in the second range, the radiator among the radiator circuit and the heater circuit. The circuit is opened,
The third range is a range obtained in a state in which the control valve is displaced in the direction opposite to the specific direction beyond the first range, and in the third range, the radiator circuit and the heater circuit The heater circuit is opened inside,
The fourth range is a range obtained by further displacing the control valve in the opposite direction beyond the third range, and in the fourth range, both the radiator circuit and the heater circuit are Released,
In the third range or the fourth range, the driving means may be configured such that the control position of the control valve when the opening degree of the heater circuit is greater than or equal to a first predetermined opening degree is the abnormal position. When there is a heater request for circulating the cooling water in the circuit, the control position of the control valve is changed depending on whether the temperature of the cooling water is equal to or higher than a predetermined temperature,
The driving means has a situation in which the control position of the control valve becomes the abnormal position when the opening degree of the heater circuit is not less than a second predetermined opening degree and less than the first predetermined opening degree in the third range. Below, when there is a heater request, the control position of the control valve is changed based on the outside air temperature in addition to the temperature of the cooling water.

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