JP2011157035A - Cooling device for hybrid vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cooling device for a hybrid vehicle capable of quickly heating the cooling water of a cooling water circuit for engine cooling during engine warmup after the start of the hybrid vehicle. <P>SOLUTION: A water jacket 14 for making cooling water which receives the heat of a motor 2 flow is connected to either a first cooling water circuit through which cooling water passing through an engine 1 and a heater core 7 circulates or a second cooling water circuit through which the cooling water passing through an invertor 4 circulates. Then, the water jacket 14 for making the cooling water which receives the heat of the motor 2 flow is separated from the second cooling water circuit, and connected to the first cooling water circuit during the warmup of the engine 1. In this case, when the cooling water of the first cooling water circuit passes through the water jacket 14, the cooling water is effectively heated by heat emitted by the motor 2, so that the cooling water is quickly heated. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a cooling device for a hybrid vehicle.

  In a hybrid vehicle equipped with an engine and a motor as a prime mover, the engine is cooled by cooling water, and a transaxle provided with the motor and an inverter used when driving the motor are also cooled by cooling water.

  Here, with respect to the engine, it is preferable to reduce the rotational resistance due to the oil that lubricates the engine in order to improve fuel efficiency. For this reason, as the oil for engine lubrication, after the engine warm-up is completed, the viscosity of the oil does not cause excessive rotation resistance of the engine, and the engine can be properly lubricated with the oil. Is selected. In the engine, the temperature of the oil is set to a value (warm-up determination value) at which the viscosity of the oil does not cause excessive rotation resistance of the engine and the engine can be properly lubricated with the oil. Until it rises, it is determined that the engine is warming up, and after it has risen above that value, it is determined that the engine has been warmed up.

  On the other hand, the temperature at which the motor can be driven most efficiently (optimum temperature) is lower than the warm-up determination value. For this reason, in order to drive the motor efficiently, it is preferable to keep the temperature of the motor at the optimum temperature as much as possible. In addition, regarding the inverter used for driving the motor, the temperature range that guarantees the normal operation of the inverter is lower than the warm-up determination value of the engine, so the inverter temperature is kept below the warm-up determination value. It is preferable that the temperature does not rise above the upper limit of the temperature range.

  Thus, since the required temperature of the engine is different from the required temperature of the motor and the inverter, as shown in Patent Document 1, for cooling the engine and for cooling the transaxle system (including the motor and the inverter) It is conceivable to provide two independent cooling water circuits.

  A cooling water circuit for cooling the engine (hereinafter referred to as a first cooling water circuit) circulates cooling water that passes through the engine and performs heat exchange with the engine. Therefore, when the temperature of the engine is higher than the temperature of the cooling water in the first cooling water circuit, the engine is deprived by the cooling water and the engine is cooled. The first cooling water circuit may be provided with a heater core that is used when heating the passenger compartment. The heater core warms the air by heat exchange between the cooling water of the first cooling water circuit passing through the heater core and the air blown into the passenger compartment.

  A cooling water circuit for cooling the transaxle system (hereinafter referred to as a second cooling water circuit) circulates cooling water that passes through the transaxle and the inverter and exchanges heat with them. Therefore, when the temperature of the inverter is higher than the temperature of the cooling water in the second cooling water circuit, the cooling water removes the heat of the inverter and cools the inverter. Furthermore, when the cooling water in the second cooling water circuit passes through the transaxle, heat exchange is also performed between the motor provided in the transaxle and the cooling water. For this reason, when the temperature of the motor is higher than the temperature of the cooling water in the second cooling water circuit, the heat of the motor is taken away by the cooling water and the motor is cooled.

  As described above, by providing the first cooling water circuit for cooling the engine and the second cooling water circuit for cooling the transaxle system as independent cooling water circuits, the required engine temperature, the motor and the inverter Even if the required temperature is different, temperature adjustment corresponding to the required temperature is possible. That is, the temperature of the cooling water in the first cooling water circuit is adjusted to a value corresponding to the required temperature of the engine, and separately, the cooling temperature of the second cooling water circuit corresponds to the required temperature of the motor and the inverter. It can be adjusted to be a value. This makes it possible to achieve both temperature adjustment corresponding to the required temperature of the engine and temperature adjustment corresponding to the required temperature of the motor and the inverter.

  By the way, in a hybrid vehicle, there are many situations in which driving of the engine is stopped, such as motor traveling that is driven only by the motor, and therefore it is difficult for the engine to warm up due to heat generated by the engine itself after the start of the vehicle. Further, since it is difficult for the temperature of the cooling water in the first cooling water circuit to increase due to the heat generated by the engine, the temperature of the cooling water is too low after the start of the vehicle, and the vehicle interior uses the heat of the cooling water. There is also a risk that the period during which no heating can be performed becomes longer.

  In order to cope with this, it is conceivable to provide an exhaust heat recovery device shown in Patent Document 2 in the first cooling water circuit. In this case, the cooling water in the first cooling water circuit is heated by the exhaust heat recovery device using the heat of the engine exhaust, thereby promoting the temperature rise of the cooling water after the start of the vehicle. In this way, the temperature increase of the cooling water in the first cooling water circuit after the start of the vehicle is promoted, so that the warm-up of the engine after the start of the vehicle is also promoted.

  Patent Document 2 also discloses a technique for preventing the heat of the engine from being taken away by the cooling water passing through the inside of the engine by prohibiting the passage of the cooling water of the engine while the engine is warming up. Yes. If this technology is applied, the warm-up of the engine after the start of the vehicle is promoted, and the cooling water staying in the engine out of the cooling water in the first cooling water circuit receives heat from the engine and quickly. The temperature starts to rise.

JP 2007-216799 A (paragraph [0071]) JP 2008-255944 A (paragraphs [0002], [0003], [0011])

  As described above, the first cooling water after the start of the vehicle is started by providing the exhaust heat recovery device in the first cooling water circuit or prohibiting the passage of the cooling water inside the engine during engine warm-up. The temperature rise of the cooling water in the circuit can be promoted.

  However, even if the exhaust heat recovery device is provided in the first cooling water circuit, there is a limit to the temperature increase of the cooling water in the first cooling water circuit using the heat of the exhaust gas of the engine in the exhaust heat recovery device. Therefore, the temperature of the cooling water in the first cooling water circuit cannot be raised to a value necessary for heating the passenger compartment at an early stage after the start of the vehicle.

  Further, if the passage of the cooling water inside the engine is prohibited during the warming up of the engine, the warming up of the engine is promoted, so that the warming up of the engine can be completed early after the start of the vehicle. Of the cooling water in the cooling water circuit, it cannot be expected to promote the temperature rise of the cooling water outside the engine. Therefore, after the start of the vehicle, it cannot be denied that the period during which the temperature of the cooling water in the first cooling water circuit is too low to heat the passenger compartment using the heat of the cooling water becomes long. .

  The present invention has been made in view of such circumstances, and an object of the present invention is to quickly raise the temperature of cooling water in a cooling water circuit for engine cooling during engine warm-up after the start of a hybrid vehicle. An object of the present invention is to provide a cooling device for a hybrid vehicle that can be used.

  In order to achieve the above object, according to the first aspect of the present invention, a hybrid vehicle equipped with an engine and a motor as a prime mover is provided with a first coolant circuit for circulating coolant through the engine, A second cooling water circuit is provided that circulates cooling water that cools an inverter used when driving the motor. The cooling water circulating through the first cooling water circuit also passes through the heater core used when heating the passenger compartment of the hybrid vehicle. And the water jacket which flows the cooling water which receives the heat from the said motor is connected to either one of these 1st cooling water circuits and the 2nd cooling water circuits. When the water jacket is connected to the first cooling water circuit, when the cooling water circulating in the first cooling water circuit passes through the water jacket, heat exchange is performed between the cooling water and the motor. Further, when the water jacket is connected to the second cooling water circuit, heat exchange is performed between the cooling water and the motor when the cooling water circulating through the second cooling water circuit passes through the water jacket. Switching between the first cooling water circuit and the second cooling water circuit to which the water jacket is connected is performed through a switching control unit. The switching control unit disconnects the water jacket from the second cooling water circuit and connects it to the first cooling water circuit while the engine is warming up. For this reason, during the warm-up of the engine after the start of the hybrid vehicle, the cooling water in the first cooling water circuit is effectively heated by the heat generated by the motor, whereby the cooling water quickly rises in temperature. .

  According to invention of Claim 2, the cooling water which flows through a water jacket receives the heat from the coil in the state which interrupted | blocked between the coil of a motor, and external air. For this reason, the heat which a coil emits during the drive of a motor can be efficiently transmitted to the cooling water of a water jacket.

  According to the third aspect of the present invention, when it is no longer necessary to transfer the heat of the motor to the cooling water of the first cooling water circuit after the warm-up of the engine is completed, the water jacket is disconnected from the first cooling water circuit. Connected to the second connection circuit. As for the motor, the temperature at which it can be driven most efficiently (optimum temperature) is a value lower than the temperature of the cooling water in the first cooling water circuit after the completion of engine warm-up. For this reason, if the connection of the water jacket to the first cooling water circuit is maintained after the warm-up of the engine is completed, the cooling efficiency of the motor deteriorates due to the heat generation of the engine, and accordingly, the motor temperature is set to the optimum temperature. May not be able to be retained. In this regard, after the engine is warmed up, if the water jacket is connected to the second cooling water circuit as described above, the motor is driven by the cooling water in the second cooling water circuit, which is a circuit different from the first cooling water circuit. Since the engine is cooled, the cooling efficiency of the motor does not deteriorate due to the heat generation of the engine after the engine warm-up is completed. Therefore, after the engine is warmed up, the motor temperature can be maintained at the optimum temperature, and the driving efficiency of the motor can be optimized.

  According to the invention described in claim 4, the heat radiation of the cooling water circulating through the first cooling water circuit is performed by the first radiator provided in the second cooling water circuit, and the second cooling water circuit is circulated. The cooling water is radiated by a second radiator provided in the second cooling water circuit. After the engine warm-up is completed, the water jacket is normally connected to the second cooling water circuit, and the motor is cooled by the cooling water in the second cooling water circuit. In this case, the inverter and the motor are cooled by the cooling water of the second cooling water circuit. And when the cooling water heated up by receiving heat from the inverter and the motor passes through the second radiator, it radiates heat to the outside air through heat exchange with the outside air.

  Regarding the motor, the temperature at which it can be driven most efficiently (optimum temperature) is a value lower than the temperature of the cooling water in the first cooling water circuit after completion of warming up of the engine. For the inverter, the temperature range of the inverter that guarantees normal operation is lower than the temperature of the cooling water in the first cooling water circuit after completion of warming up of the engine. Then, after the engine warm-up is completed, the size of the second radiator in the second coolant circuit is set so that the temperature requirements of these motors and inverters can be satisfied after the engine warm-up is completed.

  By the way, in order to maintain the temperature of the inverter within the temperature range that guarantees the normal operation of the inverter even when the drive load of the inverter becomes high after the engine warm-up is completed, It is effective to increase the size of the radiator to keep the temperature of the cooling water in the second cooling water circuit low. However, when the size of the second radiator is increased, when the second radiator is mounted on the hybrid vehicle, there is a problem of how to secure a space for mounting the second radiator. In order to cope with this, when the engine is warmed up and the drive load of the inverter is high, the water jacket is disconnected from the second coolant circuit and connected to the first coolant circuit. In this case, the motor that was the heat source for raising the temperature of the cooling water in the second cooling water circuit is disconnected from the second cooling water circuit. For this reason, the heat of the motor is not received by the cooling water of the second cooling water circuit, and the temperature rise of the cooling water of the second cooling water circuit when the drive load of the inverter is increased correspondingly is suppressed. Accordingly, it is possible to suppress an increase in the size of the second radiator for radiating the cooling water in the second cooling water circuit, and it is possible to suppress the problem of securing a space for mounting the second radiator in the hybrid vehicle. it can.

  Note that, as described above, the motor separated from the second cooling water circuit is cooled by the cooling water circulating in the first cooling water circuit. As for the motor, as described above, the temperature (optimum temperature) at which the motor can be driven most efficiently becomes a value lower than the temperature of the cooling water in the first cooling water circuit after completion of warming up of the engine. For this reason, after the warm-up of the engine is completed and the drive efficiency of the inverter becomes high, the water jacket is connected to the first cooling water circuit and the motor is cooled by the cooling water of the circuit. There is a high possibility that the motor temperature cannot be maintained at the optimum temperature. However, even in this case, it is possible to cool the motor with the cooling water of the first cooling water circuit so that the temperature of the motor does not rise so high that the reduction of the driving efficiency of the motor becomes a problem.

  According to the invention described in claim 5, during the warm-up of the engine, the water jacket is connected to the first cooling water circuit so that the cooling water inside the water jacket flows upstream of the heater core. For this reason, the cooling water circulating through the first cooling water circuit is heated by the motor through the water jacket, and then passes through the heater core and the exhaust heat recovery device in this order. Here, the heater core warms the air by heat exchange between the cooling water passing therethrough and the air blown into the passenger compartment, and allows the cooling water immediately after being heated by the motor to pass therethrough. For this reason, when heating the passenger compartment while the engine is warming up, the heat of the motor can be efficiently transmitted to the air sent to the passenger compartment, thereby effectively heating the passenger compartment. it can. The exhaust heat recovery unit heats the cooling water by exchanging heat between the cooling water passing therethrough and the exhaust of the engine, and passes the cooling water whose temperature has dropped immediately after being radiated by the heater core. Let For this reason, when the exhaust heat is transmitted to the cooling water by the exhaust heat recovery device while the engine is warming up, the heat can be efficiently transmitted. In other words, exhaust heat recovery through the exhaust heat recovery device can be performed efficiently.

  According to the sixth aspect of the present invention, after the warm-up of the engine is completed, the water jacket is connected to the second cooling water circuit so that the cooling water in the water jacket flows downstream of the inverter and upstream of the radiator. . For this reason, the cooling water circulating through the second cooling water circuit is heated by the motor through the water jacket, and then passes through the radiator and the inverter in this order. Here, the radiator allows the cooling water of the second cooling water circuit to pass through and dissipates the cooling water, and allows the cooling water immediately after being heated by the motor to pass therethrough. For this reason, when the motor is cooled with the cooling water of the second cooling water circuit after the completion of the engine warm-up, the cooling water heated by the heat of the motor can be effectively radiated by the radiator. The cooling water whose temperature has been reduced by the heat radiation can be sent to the inverter. Therefore, even if the temperature of the cooling water in the second cooling water circuit is raised by using the motor as a heat source, it is possible to suppress a decrease in the cooling efficiency of the inverter caused thereby.

Schematic which shows the whole structure of the cooling device in this embodiment. The schematic diagram which shows the circulation aspect of the cooling water in the cooling device. The schematic diagram which shows the circulation aspect of the cooling water in the cooling device. The schematic diagram which shows the circulation aspect of the cooling water in the cooling device. The schematic diagram which shows the circulation aspect of the cooling water in the cooling device. The flowchart which shows the execution procedure of the switching control which switches the connection destination of a water jacket between a 1st cooling water circuit and a 2nd cooling water circuit.

Hereinafter, an embodiment in which the present invention is embodied in a cooling device for a hybrid vehicle will be described with reference to FIGS.
In such a hybrid vehicle, as shown in FIG. 1, an engine 1 and a motor 2 are mounted as a prime mover. The motor 2 is provided on the transaxle 3 of the hybrid vehicle. When the motor 2 is driven, an inverter 4 is used.

  The hybrid vehicle cooling device includes a first coolant circuit in which coolant is circulated through the interior of the engine 1 by driving the water pump 5. The first coolant circuit includes a main path that returns to the water pump 5 through the water pump 5, the engine 1, the valve 6, the heater core 7, the exhaust heat recovery unit 8, and the thermostat 9, and the engine 1 in the main path. A bypass path is formed that branches from the portion that passes through the first radiator 10 and then merges with the main path in the thermostat 9.

  The heater core 7 functions as a heat exchanger that warms air blown into the vehicle interior through heat exchange between air and cooling water. The exhaust heat recovery unit 8 functions as a heat exchanger that performs heat exchange between the exhaust of the engine 1 and the cooling water of the first cooling water circuit, thereby heating the cooling water with the heat of the exhaust. The first radiator 10 is for releasing heat of the cooling water in the first cooling water circuit into the outside air. The thermostat 9 always allows the flow of the cooling water in the main path, and opens when the temperature of the cooling water after passing through the exhaust heat recovery device 8 exceeds a specified value. The cooling water is allowed to circulate through the first radiator 10. The thermostat 9 is closed when the temperature after passing through the exhaust heat recovery device 8 is less than the specified value, and prohibits the circulation of the cooling water through the first radiator 10.

  In addition to the first cooling water circuit, the hybrid vehicle cooling device also includes a second cooling water circuit in which cooling water circulates through the interior of the inverter 4 by driving the water pump 11. In the second cooling water circuit, the cooling water discharged from the water pump 11 returns to the water pump 11 through the second radiator 12, the inverter 4, and the valve 13. The second radiator 12 is for releasing the heat of the cooling water in the second cooling water circuit into the outside air.

Next, a structure for cooling the motor 2 in the cooling device for the hybrid vehicle will be described in detail.
The transaxle 3 is formed with a water jacket 14 through which cooling water that receives heat from the motor 2 flows. The motor 2 is cooled by the cooling water passing through the water jacket 14. The water jacket 14 is provided so that the coolant flowing therethrough receives heat from the coil 2a in a state where the coil 2a of the motor 2 and the outside air are blocked. The water jacket 14 can be connected to either the first coolant circuit or the second coolant circuit. In other words, the connection destination of the water jacket 14 can be switched between the first coolant circuit and the second coolant circuit.

  In order to switch the connection destination of the water jacket 14 as described above, specifically, the following structure is employed. That is, the upstream side of the water jacket 14 is connected to the downstream side of the water pump 5 in the bypass path of the first cooling water circuit via the passage 15 and is connected to the valve 13 of the second cooling water circuit via the passage 16. . Further, the downstream side of the water jacket 14 is connected to the valve 6 of the first cooling water circuit via the passage 17, and upstream of the water pump 11 of the second cooling water circuit and downstream of the inverter 4 via the passage 18. Connected.

  The valve 6 of the first coolant circuit includes a first port 6 a connected upstream of the heater core 7, a second port 6 b connected downstream of the engine 1, and a third port 6 c connected to the passage 17. ing. The valve 6 communicates the first port 6a with the second port 6b and shuts off the third port 6c. The valve 6 shuts off the first port 6a with respect to the second port 6b. Switching operation is performed between a connection position communicating with the 3 port 6c.

  On the other hand, the valve 13 of the second cooling water circuit includes a first port 13a connected downstream of the inverter 4, a second port 13b connected upstream of the water pump 11, and a third port connected to the passage 16. 13c. The valve 13 communicates the first port 13a with the second port 13b and shuts off the third port 13c. The valve 13 shuts off the first port 13a with respect to the second port 13b. Switching operation is performed between a connection position communicating with the 3 port 13c.

  When the valve 6 of the first cooling water circuit is switched to the connection position and the valve 13 of the second cooling water circuit is switched to the cutoff position, the cooling water discharged from the water pump 5 of the first cooling water circuit is changed to the engine 1. After passing through the passage 15, the water jacket 14, and the passage 17 in this order, it flows into the third port 6 c of the valve 6. At this time, the cooling water discharged from the water pump 11 of the second cooling water circuit sequentially passes through the second radiator 12 and the inverter 4, and then passes through the first port 13 a and the second port 13 b of the valve 13. It returns to the pump 11. Therefore, in this case, the water jacket 14 is connected to the first cooling water circuit in a state of being disconnected from the second cooling water circuit. In other words, the connection destination of the water jacket 14 is switched to the first cooling water circuit.

  When the valve 6 of the first cooling water circuit is switched to the cutoff position and the valve 13 of the second cooling water circuit is switched to the connection position, the cooling water discharged from the water pump 11 of the second cooling water circuit is After passing through the radiator 12 and the inverter 4, it flows into the valve 13 from the first port 13 a. Then, the cooling water flows out from the valve 13 to the water jacket 14 through the third port 13 c, passes through the water jacket 14 and the passage 18 in order, and then returns to the water pump 11. At this time, the cooling water discharged from the water pump 5 of the first cooling water circuit flows into the second port 6 b of the valve 6 after passing through the engine 1. Therefore, in this case, the water jacket 14 is connected to the second cooling water circuit in a state of being disconnected from the first cooling water circuit. In other words, the connection destination of the water jacket 14 is switched to the second cooling water circuit.

Next, the electrical configuration of the cooling device will be described.
The hybrid vehicle cooling device includes an electronic control device 19 that controls the drive of the motor 2 using the inverter 4 and controls the switching of the valves 6 and 13. This electronic control unit 19 is a CPU that performs various arithmetic processes related to the drive control of the motor 2 and the switching control of the valves 6, 13, a ROM that stores a control program and data, the CPU calculation results and sensor detection A RAM for temporarily storing results and the like and an I / O for input / output of signals to / from the outside are provided. The electronic control device 19 receives a detection signal from a water temperature sensor 20 that detects the temperature of the coolant near the outlet of the engine 1 in the first coolant circuit (cooling water temperature thw1).

  In a hybrid vehicle, there are many situations in which driving of the engine 1 is stopped, such as motor running that is driven only by the motor 2, and therefore it is difficult for the engine 1 to warm up due to the heat generated by the engine 1 itself after the start of the vehicle. . In addition, since the temperature of the cooling water in the first cooling water circuit due to the heat generated by the engine 1 is difficult to advance, the temperature of the cooling water is too low after the start of the hybrid vehicle, and the heater core 7 uses the heat of the cooling water. There is also a possibility that the period during which the vehicle interior cannot be heated through will be longer. In addition, although the 1st cooling water circuit is provided with the exhaust heat recovery device 8 which heats the cooling water in the circuit using the heat of the exhaust gas of the engine 1, the cooling using the exhaust heat recovery device 8 is performed. There is a limit to the temperature rise of water. For this reason, the temperature of the cooling water in the first cooling water circuit cannot be raised to a value preferable for promoting warm-up of the engine 1 or a value required for heating the passenger compartment at an early stage after starting the hybrid vehicle.

  In order to cope with such a problem, in the cooling device of the present embodiment, the temperature of the cooling water in the first cooling water circuit is quickly raised using the heat of the motor 2 while the engine 1 is warming up. That is, during the warm-up of the engine 1, the water jacket 14 for flowing the cooling water that receives the heat of the motor 2 is disconnected from the second cooling water circuit and connected to the first cooling water circuit. More specifically, as shown in FIG. 2, the connection of communicating the first port 6 a and the third port 6 c with the valve 6 of the first coolant circuit being in the disconnected state between the first port 6 a and the second port 6 b. Switch to position. Further, the valve 13 of the second cooling water circuit is switched to a blocking position where the first port 13a and the third port 13c are blocked while the first port 13a and the second port 13b are in communication with each other.

  Thereby, in the first cooling water circuit, the cooling water discharged from the water pump 5 is supplied to the engine 1, the passage 15, the water jacket 14, the passage 17, the valve 6, the heater core 7, the exhaust heat recovery device 8, and the thermostat 9. It flows in order and returns to the water pump 5. In this case, when the cooling water of the first cooling water circuit passes through the water jacket 14, the cooling water is effectively heated by the heat generated by the motor 2, thereby quickly increasing the temperature. Therefore, when the engine 1 is warmed up after the start of the hybrid vehicle, the warm-up can be completed at an early stage, and the temperature of the cooling water in the first cooling water circuit is required for heating the passenger compartment at an early stage. Can be raised to At this time, in the second cooling water circuit, the cooling water discharged from the water pump 11 flows in the order of the second radiator 12, the inverter 4, and the valve 13 and returns to the water pump 11.

  By the way, regarding the motor 2, the temperature (optimum temperature) at which the motor 2 can be driven most efficiently becomes a value lower than the temperature of the cooling water in the first cooling water circuit after the warm-up of the engine 1 is completed. For this reason, when the connection of the water jacket 14 to the first cooling water circuit is maintained after the warm-up of the engine 1 is completed, the cooling efficiency of the motor 2 deteriorates due to heat generation of the engine 1, and accordingly, the motor 2 There is a possibility that the temperature cannot be maintained at the optimum temperature. For this reason, after the warm-up of the engine 1 is completed, the water jacket 14 for flowing the cooling water that receives the heat of the motor 2 is disconnected from the first cooling water circuit and connected to the second cooling water circuit. More specifically, as shown in FIG. 3, the valve 6 of the first cooling water circuit shuts off the first port 6a and the third port 6c while keeping the first port 6a and the second port 6b in communication. Switch to position. Further, the valve 13 of the second cooling water circuit is switched to a connection position where the first port 13a and the third port 13c communicate with each other while the first port 13a and the second port 13b are shut off.

  Thereby, in the second cooling water circuit, the cooling water discharged from the water pump 11 flows in the order of the second radiator 12, the inverter 4, the valve 13, the passage 16, the water jacket 14, and the passage 18 to the water pump 11 described above. To return to. In this case, when the cooling water of the second cooling water circuit, which is a circuit different from the first cooling water circuit, passes through the water jacket 14, the motor 2 is deprived of heat, thereby effectively cooling the motor 2. Become so. For this reason, after the warm-up of the engine 1 is completed, the cooling efficiency of the motor 2 does not deteriorate due to the heat generation of the engine 1. Therefore, after the warm-up of the engine 1 is completed, the temperature of the motor 2 can be maintained at the optimum temperature, and the driving efficiency of the motor 2 can be optimized.

  At this time, if the temperature of the cooling water after passing through the exhaust heat recovery device 8 in the first cooling water circuit is less than the specified value, the thermostat 9 is closed and the cooling water through the first radiator 10 is closed. Circulation is prohibited. In this case, the cooling water is circulated only in the main path in the first cooling water circuit. That is, the cooling water discharged from the water pump 5 in the first cooling water path passes through the engine 1, the valve 6, the heater core 7, the exhaust heat recovery device 8, and the thermostat 9 in order and returns to the water pump 5. On the other hand, if the temperature of the cooling water after passing through the exhaust heat recovery device 8 in the first cooling water circuit is equal to or higher than the specified value, the thermostat 9 is opened and the first radiator 10 is passed through as shown in FIG. Cooling water circulation is allowed. In this case, in the first cooling water circuit, in addition to the circulation of the cooling water in the main path described above, the cooling water is also circulated through the bypass path. That is, the cooling water discharged from the water pump 5 returns to the water pump 5 through the main path, branches from a portion corresponding to the engine 1 in the main path, and sequentially passes through the first radiator 10 and the thermostat 9. After that, it returns to the water pump 5.

  After the engine 1 is warmed up, if the drive load of the inverter 4 increases (the drive rate of the inverter 4 increases), the temperature of the inverter 4 increases. Therefore, in order to maintain the temperature of the inverter 4 within the temperature range that guarantees the normal operation of the inverter 4 even when the drive load of the inverter 4 becomes high after the engine warm-up is completed. It is effective to increase the size of the second radiator 12 to keep the temperature of the cooling water in the second cooling water circuit low. Further, when the size of the second radiator 12 is increased, the size of the second radiator 12 is set in consideration of maintaining the temperature of the motor 2 at the optimum temperature. However, when the size of the second radiator 12 is increased as described above, it becomes a problem how to secure a space for mounting the second radiator 12 on the hybrid vehicle.

  In order to cope with such a situation, after the warm-up of the engine 1 is completed and the drive load of the inverter 4 is high, the water jacket 14 is disconnected from the second cooling water circuit as shown in FIG. 1 Connected to the coolant circuit. FIG. 2 shows a circulation mode of the cooling water in the first cooling water circuit when the temperature of the cooling water after passing through the exhaust heat recovery device 8 in the first cooling water circuit is less than the above specified value. FIG. 5 shows a cooling water circulation mode in the first cooling water circuit when the temperature of the cooling water is equal to or higher than the specified value.

  As described above, the water jacket 14 is disconnected from the second cooling water circuit and connected to the first cooling water circuit. This means that the motor 2 that is a heat source for raising the temperature of the cooling water in the second cooling water circuit is the same. It means to be disconnected from the second cooling water circuit. For this reason, the heat of the motor 2 is not received by the cooling water of the second cooling water circuit, and the temperature rise of the cooling water of the second cooling water circuit when the drive load of the inverter 4 is increased by that much. Therefore, the enlargement of the second radiator 12 for radiating the cooling water in the second cooling water circuit can be suppressed, and securing the space for mounting the second radiator 12 on the hybrid vehicle becomes a problem. Can be suppressed.

  As described above, the motor 2 separated from the second cooling water circuit is cooled by the cooling water circulating through the first cooling water circuit. With respect to the motor 2, the temperature at which it can be driven most efficiently (optimum temperature) is a value lower than the temperature of the cooling water in the first cooling water circuit after the completion of warming up of the engine 1. For this reason, after the warm-up of the engine 1 is completed and the drive load of the inverter 4 becomes high, the water jacket 14 is connected to the first cooling water circuit so that the motor is cooled by the cooling water in the circuit. Then, there is a high possibility that the temperature of the motor 2 cannot be maintained at the optimum temperature. However, even in this case, it is possible to cool the motor 2 with the cooling water of the first cooling water circuit so that the temperature of the motor 2 does not rise so high that the reduction in the driving efficiency of the motor 2 becomes a problem.

  Next, the execution procedure of the switching control for switching the connection destination of the water jacket 14 between the first cooling water circuit and the second cooling water circuit will be described with reference to the flowchart of FIG. 6 showing the switching control routine. This switching control routine is periodically executed through the electronic control unit 19 with time interruptions at predetermined time intervals.

  In this routine, it is first determined whether or not the engine 1 is warming up, that is, whether or not the coolant temperature thw1 that is substituted as the temperature of the engine 1 is equal to or higher than the warm-up determination value (S101). If the determination is affirmative, the water jacket 14 is disconnected from the second cooling water circuit and connected to the first cooling water circuit as shown in FIG. 2 or 5 (S102). On the other hand, if the determination in S101 is negative, it is determined whether or not the drive load of the inverter 4 is high (S103).

  Here, the inverter 4 is configured to increase the drive rate of the inverter 4 as the output request increases in order to increase the actual output of the motor 2 in response to an increase in the output request to the motor 2 in the hybrid vehicle. A command is received through the control device 19. Therefore, the drive load of the inverter 4 can be detected based on a drive rate command for the inverter 4 of the electronic control unit 19. When the drive load of the inverter 4 is higher than a predetermined determination level, it is determined that the drive load of the inverter 4 is high in the process of S103. As the determination level, the temperature of the inverter 4 ensures the normal operation of the inverter 4 when the water jacket 14 is connected to the second cooling water circuit and the cooling water of the circuit receives the heat of the motor 2. A level corresponding to a driving load that may be higher than the upper limit value of the temperature range is adopted.

  If a negative determination is made in the process of S102 and it is determined that the engine 1 has been warmed up, and further a negative determination is made in the process of S103 and it is determined that the driving load of the inverter 4 is low, the water jacket 14 is As shown in FIG. 3 or FIG. 4, it is disconnected from the first cooling water circuit and connected to the second cooling water circuit (S104). On the other hand, if the determination in S103 is affirmative and it is determined that the drive load of the inverter 4 is high, the water jacket 14 is disconnected from the second cooling water circuit even after the engine 1 has been warmed up. The first cooling water circuit is connected (S102).

According to the embodiment described in detail above, the following effects can be obtained.
(1) During the warm-up of the engine 1, the water jacket 14 for flowing the cooling water that receives the heat of the motor 2 is disconnected from the second cooling water circuit and connected to the first cooling water circuit. In this case, when the cooling water of the first cooling water circuit passes through the water jacket 14, the cooling water is effectively heated by the heat generated by the motor 2, thereby quickly increasing the temperature. Therefore, when the engine 1 is warmed up after the start of the hybrid vehicle, the warm-up can be completed at an early stage, and the temperature of the cooling water in the first cooling water circuit is required for heating the passenger compartment at an early stage. Can be raised to

  (2) The water jacket 14 is provided so that the cooling water flowing therethrough receives heat from the coil 2a in a state where the coil 2a of the motor 2 and the outside air are blocked. For this reason, the heat generated by the coil 2 a during driving of the motor 2 can be efficiently transmitted to the cooling water of the water jacket 14.

  (3) If the connection of the water jacket 14 to the first cooling water circuit is maintained after the warm-up of the engine 1 is completed, the cooling efficiency of the motor 2 deteriorates due to the heat generation of the engine 1, and accordingly the motor 2 May not be maintained at a temperature (optimum temperature) at which the motor 2 can be driven most efficiently. However, after the engine 1 has been warmed up, the water jacket 14 through which the cooling water receiving the heat of the motor 2 flows is disconnected from the first cooling water circuit and connected to the second cooling water circuit. Thereby, when the cooling water of the second cooling water circuit, which is a circuit different from the first cooling water circuit, passes through the water jacket 14, the motor 2 is deprived of heat, thereby effectively cooling the motor 2. Become so. For this reason, the cooling efficiency of the motor 2 does not deteriorate due to the heat generation of the engine 1 after the warm-up of the engine 1 is completed. Therefore, after the warm-up of the engine 1 is completed, the temperature of the motor 2 can be maintained at the optimum temperature, and the driving efficiency of the motor 2 can be optimized.

  (4) When the warming up of the engine 1 is completed and the drive load of the inverter 4 is high, the water jacket 14 is disconnected from the second cooling water circuit and connected to the first cooling water circuit. In this case, the motor 2 that was a heat source for raising the temperature of the cooling water in the second cooling water circuit is disconnected from the second cooling water circuit. For this reason, the heat of the motor 2 is not received by the cooling water of the second cooling water circuit, and the temperature rise of the cooling water of the second cooling water circuit when the drive load of the inverter 4 is increased by that much. Therefore, the enlargement of the second radiator 12 for radiating the cooling water in the second cooling water circuit can be suppressed, and securing the space for mounting the second radiator 12 on the hybrid vehicle becomes a problem. Can be suppressed.

  (5) The connection of the water jacket 14 to the first cooling water circuit during the warm-up of the engine 1 is performed so that the cooling water inside the water jacket 14 flows upstream of the heater core 7 in the first cooling water circuit. An exhaust heat recovery device 8 is provided downstream of the heater core 7 in the first cooling water circuit. Therefore, the cooling water circulating in the first cooling water circuit during the warm-up of the engine 1 is heated by the motor 2 through the water jacket 14 and then passes through the heater core 7 and the exhaust heat recovery device 8 in this order. It will be. Here, the heater core 7 warms the air by heat exchange between the cooling water passing therethrough and the air blown into the passenger compartment, and allows the cooling water immediately after being heated by the motor 2 to pass therethrough. For this reason, when heating the passenger compartment while the engine 1 is warming up, the heat of the motor 2 can be efficiently transmitted to the air sent to the passenger compartment, thereby effectively heating the passenger compartment. be able to. The exhaust heat recovery unit 8 heats the cooling water by exchanging heat between the cooling water passing through the exhaust gas and the exhaust of the engine 1. Allow water to pass through. For this reason, when the exhaust heat is transmitted to the cooling water by the exhaust heat recovery device 8 while the engine 1 is warmed up, the heat can be efficiently transmitted. In other words, exhaust heat recovery through the exhaust heat recovery device 8 can be performed efficiently.

  (6) The connection of the water jacket 14 to the second cooling water circuit after the warm-up of the engine 1 is completed is such that the cooling water inside the water jacket 14 flows downstream of the inverter 4 and upstream of the second radiator 12. To be done. For this reason, the cooling water circulating through the second cooling water circuit is heated by the motor 2 through the water jacket 14 and then passes through the second radiator 12 and the inverter 4 in this order. Here, the second radiator 12 allows the cooling water of the second cooling water circuit to pass through and dissipates the cooling water, and allows the cooling water immediately after being heated by the motor 2 to pass therethrough. For this reason, when the motor 2 is cooled with the cooling water of the second cooling water circuit after the warm-up of the engine 1 is completed, the cooling water heated by the heat of the motor 2 is effective in the second radiator 12. The cooling water whose temperature is reduced by the heat radiation can be sent to the inverter 4. Therefore, even if the temperature of the cooling water in the second cooling water circuit is raised by using the motor 2 as a heat source, it is possible to suppress a decrease in the cooling efficiency of the inverter 4 due to this.

In addition, the said embodiment can also be changed as follows, for example.
-You may change suitably the connection position with respect to the 1st cooling water circuit of the water jacket 14 within the circuit.

-You may change suitably the connection position with respect to the 2nd cooling water circuit of the water jacket 14 within the circuit.
The water jacket 14 is provided so that the cooling water flowing therethrough receives heat from the coil 2a in a state where the coil 2a of the motor 2 and the outside air are blocked, but the motor 2 can be cooled. As long as it exists, you may provide in another aspect and it does not necessarily need to provide as mentioned above.

  A passage that bypasses the engine 1 is provided in the main path of the first cooling water circuit, and the passage of the cooling water inside the engine 1 is prohibited while the engine 1 is warmed up. In this case, while the engine 1 is warming up, the cooling water is circulated through the main path via the passage. According to this configuration, it is possible to promote warm-up of the engine 1 due to heat generated by the engine 1 itself. Further, during the warm-up of the engine 1, the cooling water circulating in the first cooling water circuit passes through the water jacket 14 and rises in temperature, and then the cooling water passes through the interior of the engine 1 to generate heat. There is no deprivation. For this reason, while the engine 1 is warming up, the temperature of the cooling water circulating in the first cooling water circuit quickly rises to a value necessary for heating the passenger compartment, thereby early in the passenger compartment after the start of starting the hybrid vehicle. It becomes possible to perform heating.

  DESCRIPTION OF SYMBOLS 1 ... Engine, 2 ... Motor, 2a ... Coil, 3 ... Transaxle, 4 ... Inverter, 5 ... Water pump, 6 ... Valve (switching control part), 6a ... 1st port, 6b ... 2nd port, 6c ... 1st 3 port, 7 ... heater core, 8 ... exhaust heat recovery device, 9 ... thermostat, 10 ... first radiator, 11 ... water pump, 12 ... second radiator, 13 ... valve (switching control unit), 13a ... first port, 13b ... 2nd port, 13c ... 3rd port, 14 ... Water jacket, 15-18 ... Passage (switching control part), 19 ... Electronic control unit (switching control part), 20 ... Water temperature sensor.

Claims (6)

Applied to a hybrid vehicle equipped with an engine and a motor as a prime mover, used for heating a passenger compartment, a first cooling water circuit for circulating cooling water through the engine, and when driving the motor In a cooling device for a hybrid vehicle, comprising: a second cooling water circuit that circulates cooling water for cooling an inverter used in
A water jacket that can be connected to either the first cooling water circuit or the second cooling water circuit and that flows cooling water that receives heat from the motor;
A switching control unit for switching the connection destination of the water jacket between the first cooling water circuit and the second cooling water circuit;
With
The cooling control device for a hybrid vehicle, wherein the switching control unit disconnects the water jacket from the second cooling water circuit and connects it to the first cooling water circuit while the engine is warming up. 2. The cooling device for a hybrid vehicle according to claim 1, wherein the water jacket is provided so that the cooling water flowing therethrough receives heat from the coil in a state where the space between the coil of the motor and the outside air is blocked. The cooling device for a hybrid vehicle according to claim 1, wherein the switching control unit disconnects the water jacket from the first cooling water circuit and connects it to the second cooling water circuit after the warm-up of the engine is completed. The first cooling water circuit includes a first radiator that dissipates the cooling water by passing the cooling water circulating inside the first cooling water circuit,
The second cooling water circuit includes a second radiator that dissipates the cooling water by passing the cooling water circulating through the inside thereof.
The switching control unit disconnects the water jacket from the second cooling water circuit and connects it to the first cooling water circuit when engine warm-up is completed and the drive load of the inverter is high. Hybrid vehicle cooling system. The first cooling water circuit includes a waste heat recovery device that heats the cooling water downstream of the heater core by exchanging heat between the engine exhaust and the cooling water of the first cooling water circuit,
The heater core warms the air by heat exchange between cooling water passing through the interior of the heater core and air blown into the passenger compartment.
The cooling device for a hybrid vehicle according to claim 1, wherein the water jacket is connected to the first cooling water circuit so that cooling water inside the water jacket flows upstream of the heater core during warming up of the engine. The second cooling water circuit includes a radiator that dissipates the cooling water by passing the cooling water in the circuit upstream of the inverter,
The said water jacket is connected with respect to a said 2nd cooling water circuit so that the cooling water inside a water jacket may flow downstream of the said inverter and upstream of the said radiator after engine warm-up completion. Hybrid vehicle cooling system.

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