JP5837458B2 - Rotating electric machine cooling system - Google Patents

Description

  The present invention relates to a rotating electrical machine cooling system including a mechanical refrigerant pump driven by an internal combustion engine and an electric refrigerant pump driven by a power source.

  A vehicle equipped with an internal combustion engine, which is an engine, and a rotating electrical machine, in addition to a mechanical oil pump driven by the internal combustion engine to cool a rotating electrical machine such as an electric motor or an automatic transmission, An electric oil pump that is an electric type driven by a battery or the like even when stopped is used.

  For example, Patent Document 1 states that execution of automatic engine stop control is prohibited for a vehicle including an electric oil pump in addition to a mechanical oil pump depending on the driving state of the electric oil pump. It has been. Further, in Patent Document 1, a motor rotation speed target value, an upper limit value and a lower limit value thereof are determined based on the oil temperature of the hydraulic oil detected by the oil temperature sensor, and the electric oil If the actual rotational speed of the pump motor exceeds the above upper limit value or falls below the above lower limit value, it is determined that the hydraulic pressure required during automatic engine stop cannot be supplied by the electric oil pump, It is described that execution of automatic engine stop control is prohibited. In this case, the hydraulic pressure required for the hydraulic control circuit is supplied via the mechanical oil pump.

JP 2011-106296 A

  By the way, when the temperature of the rotating electrical machine rises, the running performance of the vehicle driven by the rotating electrical machine decreases, and the fuel consumption performance deteriorates. For this reason, it is conceivable to reduce the temperature of the refrigerant discharged from the refrigerant pump, for example, lubricating oil called ATF, and then supply this refrigerant to the rotating electrical machine to improve the cooling performance of the rotating electrical machine. In order to lower the temperature of the refrigerant, it is conceivable to provide a refrigerant heat exchanger that exchanges heat between the refrigerant and a second refrigerant such as cooling water on the discharge side of the refrigerant pump. Further, in order to cool the second refrigerant passing through the refrigerant heat exchanger, a radiator for exchanging heat between the second refrigerant and air is provided, and the second refrigerant circulation path including the radiator and the refrigerant heat exchanger is provided in the second refrigerant circulation path. Circulating the refrigerant is also conceivable. However, if the refrigerant is passed through the refrigerant heat exchanger without changing the refrigerant passage amount regardless of the temperature of the second refrigerant, the refrigerant radiates heat regardless of the temperature of the second refrigerant in the refrigerant heat exchanger. In such a configuration, there is room for improvement from the viewpoint of efficiently using the refrigerant heat exchanger, promoting the temperature drop of the refrigerant, and efficiently improving the cooling performance of the rotating electrical machine. On the other hand, when an electric oil pump and a mechanical oil pump are used as the refrigerant pump, the magnitude relationship between the refrigerant discharge amounts of both oil pumps may change depending on conditions.

  An object of the present invention is to efficiently improve the cooling performance of a rotating electrical machine in a configuration in which refrigerant is discharged by an electric oil pump and a mechanical oil pump and the discharged refrigerant is cooled by a refrigerant heat exchanger in a rotating electrical machine cooling system. It is to improve.

  The rotating electrical machine cooling system according to the present invention drives a mechanical refrigerant pump driven by an internal combustion engine, an electric refrigerant pump driven by a power source, and one of the mechanical refrigerant pump and the electric refrigerant pump. A refrigerant pump drive control unit for controlling the driving of the refrigerant pump so as not to drive the other, and a refrigerant heat exchanger provided on the discharge side of each refrigerant pump, which is discharged from each refrigerant pump The refrigerant heat exchanger for exchanging heat between the first refrigerant and the second refrigerant flowing through the second refrigerant circuit, and is discharged from one of the mechanical refrigerant pump and the electric refrigerant pump to exchange the refrigerant heat. The first refrigerant that has passed through the cooler is supplied to a rotating electric machine to cool the rotating electric machine, and the refrigerant pump drive control unit is configured to change the temperature of the second refrigerant that passes through the refrigerant heat exchanger according to the temperature of the second refrigerant. A rotary electric machine cooling system, characterized in that to drive the 械式 coolant pump or the electric coolant pump as a drive-side refrigerant pump.

  According to the rotating electrical machine cooling system of the present invention, the mechanical refrigerant pump or the electric refrigerant pump is driven as the driving refrigerant pump according to the temperature of the second refrigerant that passes through the refrigerant heat exchanger and exchanges heat with the refrigerant. Therefore, in the configuration in which the refrigerant is discharged by the electric oil pump and the mechanical oil pump and the discharged refrigerant is cooled by the refrigerant heat exchanger, the cooling performance of the rotating electrical machine can be improved efficiently.

It is a figure which shows schematic structure of the rotary electric machine cooling system in 1st Embodiment which concerns on this invention. In the rotating electrical machine cooling system of FIG. 1, when driving a mechanical oil pump, it is the schematic which shows a mode that a rotating electrical machine is cooled with a refrigerant | coolant. In the rotating electrical machine cooling system of FIG. 1, it is the schematic which shows a mode that a rotating electrical machine is cooled with a refrigerant | coolant, when driving an electrically driven oil pump. In 1st Embodiment, it is a figure which shows one example of the relationship between the amount of discharge oil of a mechanical oil pump (MOP) and an electric oil pump (EOP), and an engine speed. In the rotating electrical machine cooling system of the first embodiment, a method for determining whether to drive an electric oil pump or a mechanical oil pump when an initial condition for driving the electric oil pump is satisfied. It is a flowchart to show. In the rotating electrical machine cooling system according to the second embodiment of the present invention, whether an electric oil pump or a mechanical oil pump is driven when an initial condition for driving the electric oil pump is satisfied. It is a flowchart which shows the 1st step of the method to determine. It is a flowchart which shows the 2nd step of the method of determining whether to drive an electric oil pump or a mechanical oil pump in the rotary electric machine cooling system of 2nd Embodiment. It is a flowchart which shows the 3rd step of the method of determining whether an electric oil pump is driven or a mechanical oil pump is driven in the rotary electric machine cooling system of 2nd Embodiment.

  Embodiments according to the present invention will be described below in detail with reference to the drawings. Below, the case where this invention is applied to the hybrid vehicle which mounts an engine and two rotary electric machines as a vehicle is demonstrated, but this invention does not limit the vehicle which mounts a rotary electric machine. For example, the rotating electrical machine cooling system of the present invention can be mounted on an electric vehicle that is not mounted with an engine that is an internal combustion engine. Moreover, although the structure which has an engine, two rotary electric machines, and the power transmission mechanism provided between them is demonstrated as a motive power apparatus of a hybrid vehicle, this is also the illustration for description. Here, the hybrid vehicle only needs to have an engine and a rotating electrical machine, and the relationship between the output of the engine and the output of the rotating electrical machine can be appropriately changed according to the specifications of the vehicle. In addition, a case where two rotating electrical machines mounted on a vehicle are provided and each rotating electrical machine is a motor generator having the functions of both an electric motor and a generator will be described. The case where one rotary electric machine which functions as a generator is mounted in a vehicle may be sufficient.

  In the following, ATF (automatic transmission fluid) used as lubricating oil as a refrigerant for cooling the rotating electrical machine will be described, but this is an example, and other cooling fluid may be used. Accordingly, the notation of an oil pump is used for the refrigerant pump that circulates the refrigerant, and this is also adapted to the case where ATF is used.

  Moreover, as a power supply for the drive circuit of the electric oil pump, a low voltage power supply independent from the power supply device for the rotating electrical machine will be described, but this is an example for explanation. For example, it is also possible to employ one that supplies electric power that has been converted to a low voltage from a high-voltage power supply device of a rotating electrical machine to a drive circuit of an electric oil pump.

  In the following, a configuration in which the rotating electrical machine and the power transmission mechanism are accommodated in one case and the refrigerant circulates in a circulation path including the case and the oil pump will be described. This is an illustrative example. . For example, the rotating electrical machine and the power transmission mechanism may not be housed in one case, and the refrigerant may be circulated through a circulation path including the rotating electrical machine, the power transmission mechanism, and the oil pump.

  Below, the same code | symbol is attached | subjected to the same element in all the drawings, and the overlapping description is abbreviate | omitted. In the description in the text, the symbols described before are used as necessary.

[First Embodiment]
FIG. 1 is a diagram showing a configuration of a rotating electrical machine cooling system 10 for a hybrid vehicle in the first embodiment according to the present invention. The rotating electrical machine cooling system 10 includes a rotating electrical machine drive cooling structure 12 mounted on a hybrid vehicle and a control unit 80.

  In the rotating electrical machine drive cooling structure 12, a power unit 14 that is a drive source of the hybrid vehicle is connected to an engine 16, a second motor generator 20 that is a rotating electrical machine indicated by MG <b> 2 in FIG. 1, and the second motor generator 20. M / G drive circuit 30 and a high voltage power supply 32 for M / G drive circuit 30. The rotating electrical machine drive cooling structure 12 further includes a case 24 that includes the second motor generator 20 inside, a mechanical oil pump 42 that supplies the refrigerant 26 to the inside of the case 24, and an electric oil pump 44. The mechanical oil pump 42 is shown as MOP in FIG. 1, and the electric oil pump 44 is shown as EOP in FIG.

  The power unit 14 includes an engine 16 that is an internal combustion engine, a second motor generator 20, and a power transmission mechanism 18 that connects the engine 16 and the second motor generator 20 so that power can be transmitted. The second motor generator 20 functions as an electric motor when electric power is supplied from the M / G drive circuit 30 and functions as a generator when driven by the engine 16 or when braking the hybrid vehicle. It is a rotating electrical machine. However, the second motor generator 20 may have another configuration such as an induction motor.

  The second motor generator 20 is provided with a rotation angle sensor 27 such as a resolver. The detected angle θm detected by the rotation angle sensor 27 is input to the control unit 80. The control unit 80 includes a motor rotation number calculation unit (not shown), and calculates the motor rotation number per unit time (for example, per minute) from the detected angle θm. The rotation angle sensor 27 and the motor rotation number calculation unit form a motor rotation number detection unit. In addition, three-phase (U-phase, V-phase, W-phase) power lines L1, L2, and L3 for connecting the second motor generator 20 and the M / G drive circuit 30 are provided. A current sensor 82 for detecting a current flowing through the two-phase power lines L1 and L2 is provided. The detection signal of each current sensor 82 is input to the control unit 80. Since the three-phase stator coils (not shown) corresponding to the three-phase power lines L1, L2, and L3 are connected at a neutral point, if any two-phase current value is acquired, the remaining one-phase The current value is also obtained by calculation in the control unit 80. However, current values for three phases can be detected by a current sensor and input to the control unit 80.

  2 and 3, the rotating electrical machine drive cooling structure 12 is provided with a first motor generator (MG1) 21 that is a rotating electrical machine having the same function as the second motor generator 20. The first motor generator 21 is connected to the power transmission mechanism 18 so as to be able to transmit power, and is mainly used as a generator, but may be used as an electric motor. The power transmission mechanism 18 has a function of distributing the power supplied to the hybrid vehicle between the output of the engine 16 and the output of the second motor generator 20. As such a power transmission mechanism 18, a planetary gear mechanism connected to three shafts of the output shaft of the engine 16, the output shaft of the second motor generator 20, and the rotation shaft of the first motor generator 21 is used. Can do. Further, the output shaft of the second motor generator 20 can be operatively connected to an axle connected to a drive wheel (not shown). In FIG. 1, the shaft connecting the power transmission mechanism 18 and the engine 16 is the output shaft 22 of the engine 16. A mechanical oil pump 42 is connected to the output shaft 22 so that power can be transmitted. For example, a mechanical oil is provided by a rotary shaft that is coaxial with the output shaft 22 and is common to the output shaft 22, or a rotary shaft that is operatively connected to the output shaft 22 via a power transmission mechanism including gears (or a belt and a pulley). The pump 42 can be driven.

  The M / G drive circuit 30 is a circuit including an inverter that performs power conversion between the DC power of the high-voltage power supply 32 and the AC power for driving the second motor generator 20. The inverter is a circuit that generates a three-phase drive signal by PWM (Pulse Width Modulation) control that appropriately adjusts on / off timings of a plurality of switching elements, and supplies the three-phase drive signal to the second motor generator 20. The PWM control is a control for modulating the pulse width by comparing a fundamental wave signal having a period corresponding to the rotation period of the second motor generator 20 and a carrier signal having a sawtooth waveform. The inverter can control the output or the rotational speed of the second motor generator 20 to a desired value by this PWM control.

  The high voltage power source 32 is a chargeable / dischargeable high voltage secondary battery. Specifically, it can be composed of a lithium ion assembled battery having a terminal voltage of about 200V to about 300V. The assembled battery is capable of outputting the predetermined terminal voltage by combining a plurality of batteries each having a terminal voltage of 1 V to several V, which is called a single battery or a battery cell. As the high voltage power supply 32, a nickel-metal hydride battery, a large capacity capacitor, or the like can be used. A DC / DC converter that boosts the voltage of the high voltage power supply 32 and supplies it to the M / G drive circuit 30 may be provided between the high voltage power supply 32 and the M / G drive circuit 30.

  Such a rotating electrical machine drive cooling structure 12 constitutes the rotating electrical machine cooling system 10 (FIG. 1) together with the control unit 80, and is mounted on a hybrid vehicle. The hybrid vehicle includes drive wheels (not shown) that drive one of the engine 16 and the second motor generator 20 as a main drive source.

  The rotating electrical machine drive cooling structure 12 is provided with a case 24 supported by the vehicle body. The case 24 includes a power transmission mechanism 18 and first and second motor generators 21 and 20 therein. Yes. In the internal space of the case 24, lubrication of the rotating parts of the power transmission mechanism 18 and the first and second motor generators 21 and 20 and cooling of the power transmission mechanism 18 and the first and second motor generators 21 and 20 are performed. The refrigerant | coolant 26 which performs is stored. As the refrigerant 26, a lubricating oil called ATF can be used.

  Further, the rotating electrical machine drive cooling structure 12 includes a rotation speed sensor 84 that is a rotation speed detection unit that detects the rotation speed per minute of the engine 16, and the refrigerant 26 provided in the case 24 and stored in the case 24. And a temperature sensor 28 which is a temperature detecting unit for detecting the temperature of the. The detection values of the sensors 84 and 28 are input to the control unit 80 using an appropriate signal line (not shown). Note that the temperature sensor 28 may be omitted and the temperature of the refrigerant 26 may not be detected.

  The rotating electrical machine drive cooling structure 12 is provided with a refrigerant circulation path 40. The refrigerant circulation path 40 has an upstream end connected to the lower portion of the case 24 and a downstream end connected to the suction side of each of the mechanical oil pump 42 and the electric oil pump 44 via a branch portion. The upstream end is connected to the discharge side of each of the mechanical oil pump 42 and the electric oil pump 44, and the downstream end is connected to the two second refrigerant passages 62 gathered at the gathering portion, and the second refrigerant passages 62 A third refrigerant path 64 connected at the collecting portion and connected at the downstream end to the oil cooler 50 as a refrigerant heat exchanger, the upstream end is connected to the oil cooler 50, and the downstream end is connected to the upper portion of the case 24. A fourth refrigerant path 66. In other words, the oil cooler 50 is connected between the discharge side of the mechanical oil pump 42 and the electric oil pump 44 and the case 24 housing the second motor generator 20. Each second refrigerant path 62 is provided with check valves 46 and 48 for preventing the refrigerant from flowing back. The refrigerant circulates in the refrigerant circulation path 40 by driving one oil pump 42 (or 44) of each of the oil pumps 42 and 44. Along with the circulation, the refrigerant 26 ejected from the downstream end of the fourth refrigerant path 66 into the case 24 is supplied to the motor generators 20 and 21. Each refrigerant path 60, 62, 64, 66 is formed by a pipe. The mechanical oil pump 42 and the electric oil pump 44 are connected in parallel with each other with respect to the flow direction of the refrigerant 26.

  The oil cooler 50 is provided on the discharge side of the oil pumps 42 and 44, and is a refrigerant 26 discharged from the oil pumps 42 and 44 and a second refrigerant flowing through a second refrigerant circulation path 90 described later, and is called LLC. Heat exchange with the cooling liquid (hereinafter simply referred to as “cooling water”) is performed. The oil cooler 50 reduces the temperature of the refrigerant 26 by heat exchange with the cooling water. That is, in order to cool the cooling water passing through the oil cooler 50, the HV radiator 88 is a second refrigerant heat exchanger that exchanges heat between the cooling water and the air, and is a radiator for an electric device. The coolant is circulated through the second refrigerant circulation path 90 including the oil cooler 50. Further, in order to circulate the cooling water in the second refrigerant circulation path 90, an electric cooling water pump (not shown) is provided in the second refrigerant circulation path 90. Note that a mechanical coolant pump driven by the engine 16 or the like may be provided instead of the electric coolant pump. The HV radiator 88 exchanges heat between the cooling water and the air passing outside, and lowers the temperature of the cooling water. For example, the HV radiator 88 is provided in the periphery of an engine radiator (not shown) that cools cooling water for cooling the engine 16, and air is supplied to the HV radiator by a common or another radiator fan (not shown). Stream.

In addition, a cooling water temperature sensor 92 that detects the temperature of the cooling water is provided in the pipeline that forms the HV radiator 88, the oil cooler 50, or the second refrigerant circulation path 90, and the cooling detected by the cooling water temperature sensor 92 is provided. The temperature _{TL of} cooling water that is water and passes through the oil cooler 50 is input to the control unit 80. In addition, in FIG. 1, the example which provided the cooling water temperature sensor 92 in said pipe line is shown.

  The mechanical oil pump 42 has a drive shaft operatively connected to the output shaft 22 of the engine 16 and is driven by the engine 16 when the engine 16 operates. That is, when the engine 16 is started, the mechanical oil pump 42 starts to be driven, and when the engine 16 is stopped, the driving of the mechanical oil pump 42 is stopped.

  The electric oil pump 44 is driven by the EOP drive circuit 72 according to a control signal from the control unit 80. The EOP drive circuit 72 is supplied with DC power from a low voltage power supply 74. The low voltage means a low voltage compared to the voltage of the high voltage power supply 32. For example, a voltage of about 12V to 16V can be used. As a motor for rotating the drive shaft of the electric oil pump 44, a three-phase synchronous motor can be used. In this case, the EOP drive circuit 72 includes an inverter having a DC / AC conversion function. Further, the output of the electric oil pump 44 can be made variable by changing the on / off duty in the PWM control of the inverter. Thus, the electric oil pump 44 is driven by the low voltage power source 74.

  As a motor for driving the electric oil pump 44, a three-phase induction motor or a single-phase AC motor can be used instead of a three-phase synchronous motor, or a DC motor can be used. The content of the EOP drive circuit 72 is changed according to the type of motor that drives the electric oil pump 44.

  The control unit 80 has a function of controlling each of the above elements as a whole. In particular, the control unit 80 does not drive the other when driving one of the mechanical oil pump 42 and the electric oil pump 44. As described above, the oil pump drive control unit 68 that controls the drive of the oil pumps 42 and 44 is provided. That is, the oil pump drive control unit 68 always drives the engine 16 during traveling, and “HV traveling mode” in which the driving wheels are driven by at least the power of the engine 16, and stops the engine 16 even during traveling, and the high voltage power supply 32. The driving wheel is driven by the second motor generator 20 driven by the electric power from the engine, and when the preset condition is satisfied, the “EV traveling mode” in which the electric oil pump 44 is driven by the low voltage power source 74 is selectively switched. Thus, when one of the mechanical oil pump 42 and the electric oil pump 44 is driven, the driving of the oil pumps 42 and 44 is controlled so as not to drive the other. Such a control part 80 can be comprised with the computer suitable for a hybrid vehicle mounting. For this reason, the oil pump drive control unit 68 selects the oil pump 42 (or 44) to be driven from the mechanical oil pump 42 and the electric oil pump 44, and the mechanical oil pump 42 and the electric oil pump 44. Among them, the refrigerant 26 discharged from one selected oil pump 42 (or 44) can be supplied to the motor generators 20, 21 to cool the motor generators 20, 21.

  Further, the control unit 80 includes a motor output calculation unit 70, and detects the detected value of each phase current detected or calculated by the current sensor 82 and the rotation angle of the second motor generator 20 detected by the rotation angle sensor 27. The output of the second motor generator 20 is calculated from the acquired value of the rotation speed of the second motor generator 20 based on the value or the like. Motor output calculation unit 70 can also be configured to calculate the output of second motor generator 20 from the torque target value of second motor generator 20 and the detected value of the rotation angle.

  FIG. 2 is a schematic diagram illustrating a state in which the rotating electrical machine is cooled by the refrigerant when the mechanical oil pump is driven in the rotating electrical machine cooling system of FIG. 1. FIG. 3 is a schematic diagram showing how the rotating electrical machine is cooled by the refrigerant when the electric oil pump is driven in the rotating electrical machine cooling system of FIG. 1. 2 and 3, the portion indicated by the solid line in the refrigerant circulation path 40 indicates that the refrigerant 26 flows, and the portion indicated by the broken line indicates that the flow of the refrigerant 26 is stopped. As shown in FIG. 2, when the mechanical oil pump 42 is driven, the electric oil pump 44 is stopped, and the motor generators 20 and 21 are cooled by the refrigerant discharged from the mechanical oil pump 42.

  Conversely, as shown in FIG. 3, when the electric oil pump 44 is driven, the mechanical oil pump 42 is stopped, and the motor generators 20 and 21 are cooled by the refrigerant discharged from the electric oil pump 44. The 2 and 3, unlike the example of FIG. 1, an example is shown in which the lower part of the case 24 and the suction side of each oil pump 42, 44 are connected by two different first refrigerant paths 61. Of course, the case 24 and the oil pumps 42 and 44 can be connected by one first refrigerant path 60 as shown in FIG. Conversely, the example of FIG. 1 can be configured similarly to the examples of FIGS. Further, as shown in FIGS. 2 and 3, a strainer 86 can be provided at the periphery of the portion connected to the case 24 at the upstream end of the first refrigerant path 61.

  Further, the oil pump drive control unit 68 determines the mechanical oil pump 42 or the electric oil pump 44 as the “drive side oil pump” according to the temperature of the cooling water passing through the oil cooler 50, and the “drive side oil pump”. Drive the pump. That is, the oil pump drive control unit 68 assumes that the predetermined condition set in advance is satisfied, and when the detected temperature of the cooling water passing through the HV radiator 88 is equal to or higher than the preset threshold temperature TA, the mechanical oil pump 42 And the oil pump 42 (or 44) with a small refrigerant | coolant discharge amount among the electric oil pumps 44 is driven as a drive side oil pump. In this case, since the oil pump 42 (or 44) having a small refrigerant discharge amount varies depending on the engine speed, an oil pump having a small refrigerant discharge amount is determined as a drive-side oil pump according to the engine speed.

  That is, FIG. 4 is a diagram showing an example of the relationship between the discharge oil amount of the mechanical oil pump (MOP) and the electric oil pump (EOP) and the engine speed in the present embodiment. As shown in FIG. 4, since the electric oil pump 44 rotates at a constant rotational speed when driven, the pump discharge oil amount is also constant and is not affected by the engine rotational speed. On the other hand, since the mechanical oil pump 42 is driven by the engine 16 (FIG. 1), the pump discharge oil amount increases to a certain value as the rotational speed of the engine 16 increases. For this reason, the magnitude relation of the discharge oil amount is reversed between the electric oil pump 44 and the mechanical oil pump 42 at the threshold rotation speed NA where the engine speed is. That is, the amount of oil discharged from the electric oil pump 44 is larger than the mechanical oil pump 42 below the threshold rotational speed NA, and the oil discharged from the mechanical oil pump 42 than the electric oil pump 44 exceeds the threshold rotational speed NA. The amount increases. For this reason, it is possible to reduce the refrigerant discharge amount by comparing the discharge oil amounts of the oil pumps 42 and 44 and driving the oil pump 42 (or 44) having a small discharge oil amount.

  Thus, by driving the oil pump 42 (or 44) with a small amount of discharged oil when the temperature of the cooling water is high, the flow rate that is the passage amount of the refrigerant 26 in the oil cooler 50 is reduced, and the refrigerant 26 is discharged. It is possible to effectively prevent an excessive burden from being applied to the oil cooler 50 and the HV radiator 88, which have a small margin in terms of temperature reduction, and to suppress a decrease in the cooling performance of the refrigerant 26 in the oil cooler 50.

  In FIG. 4, the amount of oil discharged from the mechanical oil pump 42 is a certain upper limit value and is constant regardless of the engine speed. The relief valve connected to the refrigerant circuit 40 at a certain upper limit value (see FIG. 4). (Not shown) is activated to protect the parts and the like.

  Further, the oil pump drive control unit 68 assumes that the predetermined condition set in advance is satisfied, and the mechanical oil pump 42 is detected when the detected temperature of the cooling water passing through the HV radiator 88 is lower than the preset threshold temperature TA. And the oil pump 42 (or 44) with a large refrigerant | coolant discharge amount among the electric oil pumps 44 is driven as a drive side oil pump. Further, in this case, the oil pump 42 (or 44) having a large refrigerant discharge amount also varies depending on the engine speed as can be seen from FIG. 4 above, so that the oil pump having a large refrigerant discharge amount is driven according to the engine speed. Determine as the side oil pump.

  For example, referring to FIG. 4, when the temperature of the cooling water is equal to or higher than the threshold temperature TA, the engine speed is equal to or lower than the threshold speed NA and the amount of oil discharged from the mechanical oil pump 42 is smaller than that of the electric oil pump 44. Then, the mechanical oil pump 42 is driven as a drive-side oil pump (corresponding to a circle 2 in FIG. 4). On the other hand, in the same case, when the engine speed exceeds the threshold speed NA, the amount of oil discharged from the electric oil pump 44 is smaller than that of the mechanical oil pump 42. It is driven as a pump (corresponding to 3 in FIG. 4).

  Further, when the temperature of the cooling water is lower than the threshold temperature TA, the engine speed is equal to or less than the threshold speed NA and the amount of oil discharged from the electric oil pump 44 is larger than that of the mechanical oil pump 42. It is driven as a drive side oil pump (corresponding to 1 of the circle in FIG. 4). On the other hand, when the engine speed exceeds the threshold speed NA in the same case, the amount of oil discharged from the mechanical oil pump 42 is larger than that of the electric oil pump 44. It is driven as a pump (corresponding to circle 4 in FIG. 4).

  The above description is based on the assumption that the engine speed can be detected. However, since the engine 16 is stopped during EV traveling, the pump discharge oil amount can be compared between the oil pumps 42 and 44 by the engine speed. Can not. Therefore, for example, during EV traveling, the motor output corresponding to the engine speed being equal to or less than the threshold speed NA is obtained in advance using the motor output acquired by the motor output calculation unit 70 (FIG. 1) as a criterion for determination. Which of the oil pumps 42, 44 is driven depending on whether the motor output exceeds the threshold output RA corresponding to the engine output exceeding the threshold rotational speed NA or less than the set threshold output RA To decide.

  That is, in this embodiment, the control unit 80 determines which of the mechanical oil pump 42 and the electric oil pump 44 is driven by the control method shown in the flowchart as shown in FIG. FIG. 5 shows whether the electric oil pump 44 or the mechanical oil pump 42 is driven when the initial conditions for driving the electric oil pump 44 are satisfied in the rotating electrical machine cooling system of FIG. It is a flowchart which shows the method of determining. When it is determined in the flowchart of FIG. 5 that the mechanical oil pump 42 is to be driven, the engine 16 is forcibly shifted to HV traveling or is maintained, and the mechanical oil pump 42 is driven by the engine 16. The following flowchart is executed by the oil pump drive control unit 68.

  In the flowchart of FIG. 5, in step S <b> 10 (hereinafter, step S is simply referred to as “S”), the electric oil pump 44 is driven, that is, the EV traveling and the electric oil pump 44 is driven. EOP drive initial conditions, which are preset predetermined conditions for shifting to, for example, SOC (State Of Charge) which is the charge amount of the high-voltage power supply 32 is equal to or greater than a preset predetermined amount, and the preset running conditions are When it is determined that the EOP drive initial conditions such as being satisfied are satisfied, the process proceeds to step S12.

  On the other hand, if it is determined in S10 that the EOP drive initial condition is not satisfied, the process proceeds to S14, where the mechanical oil pump 42 is driven or the electric oil pump 44 in the EV traveling mode is not driven. “No drive mode” is executed. Which mode is to be executed is determined according to a preset condition.

  Further, when it is determined that the coolant temperature (LLC temperature), which is the second refrigerant temperature detected by the coolant temperature sensor 92 in S12 of FIG. 5, is equal to or higher than a predetermined threshold temperature TA, the process proceeds to S16. To do. In S16, it is determined whether the engine speed is equal to or less than the threshold speed NA when the HV travel mode is being executed, or whether the motor output (MG2 output) is equal to or less than the threshold output when the EV travel mode is being executed. If the determination result in S16 is affirmative, the process proceeds to S18, the HV traveling mode is executed, and the mechanical oil pump 42 is driven as the drive side oil pump. In this case, it corresponds to the circle 2 in FIG.

  If the determination result in S16 of FIG. 5 is negative, the process proceeds to S20 to execute a “pump drive mode” for driving the electric oil pump 44 in the EV traveling mode, and the electric oil pump 44 is driven to the drive side. Drives as an oil pump. In this case, it corresponds to the circle 3 in FIG.

  If it is determined in S12 of FIG. 5 that the coolant temperature (LLC temperature) detected by the coolant temperature sensor 92 is lower than a predetermined threshold temperature TA, the process proceeds to S22. In S22, it is determined whether the engine speed is equal to or less than the threshold speed NA when the HV traveling mode is being executed, or whether the motor output (MG2 output) is equal to or less than the threshold output when the EV traveling mode is being executed. If the determination result in S22 is affirmative, the process proceeds to S24, where a “pump drive mode” for driving the electric oil pump 44 in the EV traveling mode is executed, and the electric oil pump 44 is driven as a drive side oil pump. To do. In this case, it corresponds to a circle 1 in FIG.

  On the other hand, when the determination result of S22 of FIG. 5 is negative, the process proceeds to S26, the HV traveling mode is executed, and the mechanical oil pump 42 is driven as a drive side oil pump. This corresponds to the circle 4 in FIG. At least a part of the functions of the control unit 80 can be realized by executing software.

  According to the rotating electrical machine cooling system 10 as described above, the mechanical oil pump 42 or the electric oil pump 44 is used as a drive-side oil pump according to the temperature of the cooling water that passes through the oil cooler 50 and exchanges heat with the refrigerant 26. To drive. Therefore, in the configuration in which the refrigerant 26 is discharged by the electric oil pump 44 and the mechanical oil pump 42 and the discharged refrigerant 26 is cooled by the oil cooler 50, the cooling performance of the motor generators 20 and 21 is efficiently improved. be able to. That is, unlike the configuration in which the refrigerant 26 radiates heat regardless of the temperature of the cooling water as the second refrigerant in the oil cooler 50, the amount of heat released from the refrigerant 26 to the cooling water can be changed according to the temperature of the cooling water. it can. For this reason, the amount of heat released from the coolant to the HV radiator 88 can be changed corresponding to the temperature of the coolant, and when the temperature of the coolant is high, the amount of heat released from the refrigerant 26 to the HV radiator 88 via the coolant is reduced. The drive-side oil pump can be selected and driven so that the amount of heat released from the refrigerant 26 to the HV radiator 88 through the cooling water is increased when the cooling water temperature is low. Therefore, when the cooling water temperature is high, the oil cooler 50 and the HV radiator 88 are not excessively burdened, and the oil cooler 50 and the HV radiator 88 are efficiently used, and the temperature decrease of the refrigerant 26 is promoted. The cooling performance of the motor generators 20 and 21 can be improved efficiently.

[Second Embodiment]
FIGS. 6 to 8 show the rotating electric machine cooling system according to the second embodiment of the present invention. It is a flowchart which shows the 1st step of the method of determining whether a pump is driven, a 2nd step, and a 3rd step, respectively.

  In the following description, the same or corresponding elements as those shown in FIGS. In particular, in this embodiment, the rotating electrical machine drive cooling structure 12 is provided with a vehicle speed sensor 29 (FIG. 1) that is a vehicle speed detection unit that detects the vehicle speed of the vehicle. The detection value of the vehicle speed sensor 29 is input to the control unit 80 using an appropriate signal line. In the present embodiment, depending on whether or not the coolant temperature is equal to or higher than the threshold temperature, the mechanical oil pump 42 or the electric motor is used by using the detected value of the engine speed and the vehicle speed and the acquired value of the motor output, respectively. The oil pump 44 is selected and driven. Such control will be described below with reference to the flowcharts of FIGS. Note that the steps S30, S32, and S34 in FIG. 6 are the same as the steps S10, S12, and S14 in the first embodiment, respectively.

  First, when it is determined in S32 in the first step of FIG. 6 that the detected coolant temperature is equal to or higher than the threshold temperature TA, the process proceeds to S40 in the second step of FIG. When it is determined that the temperature is lower than the threshold temperature TA, the process proceeds to S50 in the third step of FIG.

  In S40 of FIG. 7, it is determined whether or not the rotational speed of the engine 16 detected by the rotational speed sensor 84 is equal to or less than a predetermined threshold rotational speed NA. When the engine speed is equal to or lower than the threshold speed NA, the vehicle speed detected by the vehicle speed sensor 29 is equal to or lower than the threshold speed VA as in S42 and S46, and the motor output calculation unit 70 of the control unit 80 acquires the speed. When at least one of the output of the second motor generator 20 is equal to or less than the threshold output RA is established, the process shifts to the HV traveling mode in S44, and the mechanical oil pump 42 is driven as a drive side oil pump. In this case, it corresponds to the circle 2 in FIG.

  On the other hand, when it is determined in S42 and S46 that the vehicle speed exceeds the threshold speed VA and the output of the second motor generator 20 exceeds the threshold output RA, the pump drive mode of the EV traveling mode is set. The electric oil pump 44 is driven as a drive side oil pump. In this case, it corresponds to the circle 3 in FIG.

  Further, in S50 of FIG. 8, it is determined whether or not the detected rotational speed of the engine 16 is equal to or less than the threshold rotational speed NA, similarly to S40 of FIG. When the engine speed is equal to or lower than the threshold speed NA, the detected vehicle speed is equal to or lower than the threshold speed VA as in S52 and S56, and the obtained output of the second motor generator 20 is equal to or lower than the threshold output RA. If at least one of the above is established, in S54, the EV drive mode is shifted to the pump drive mode, and the electric oil pump 44 is driven as a drive-side oil pump. In this case, it corresponds to a circle 1 in FIG.

  On the other hand, if it is determined in S52 and S56 that the vehicle speed exceeds the threshold speed VA and the output of the second motor generator 20 exceeds the threshold output RA, the HV traveling mode is executed, The oil pump 42 is driven as a drive side oil pump. This corresponds to the circle 4 in FIG.

  In this embodiment, the mechanical oil pump is used by using the detected values of the engine speed and the vehicle speed and the acquired value of the motor output, respectively, depending on whether or not the coolant temperature is equal to or higher than the threshold temperature TA. 42 or the electric oil pump 44 can be selected and driven. Other configurations and operations are the same as those in the first embodiment.

  In the present embodiment, the case where the engine speed is equal to or higher than the threshold speed NA and the discharge amount of the electric oil pump 44 is lower than the discharge amount of the mechanical oil pump 42 has been described. However, a configuration in which the engine speed is equal to or higher than the threshold speed NA and the discharge amount of the electric oil pump 44 is higher than the discharge amount of the mechanical oil pump 42 may be employed. The present invention can also be implemented with such a configuration.

  DESCRIPTION OF SYMBOLS 10 Rotating electrical machine cooling system, 12 Rotating electrical machine drive cooling structure, 14 Power unit, 16 Engine, 18 Power transmission mechanism, 20 Second motor generator, 21 First motor generator, 22 Output shaft, 24 Case, 26 Refrigerant, 27 Rotation angle Sensor, 28 Temperature sensor, 29 Vehicle speed sensor, 30 M / G drive circuit, 32 High voltage power supply, 40 Refrigerant circuit, 42 Mechanical oil pump, 44 Electric oil pump, 46, 48 Check valve, 50 Oil cooler, 60, 61 1st refrigerant path, 62 2nd refrigerant path, 64 3rd refrigerant path, 66 4th refrigerant path, 68 Oil pump drive control part, 70 Motor output calculation part, 72 EOP drive circuit, 74 Low voltage power supply, 80 Control unit, 82 Current sensor, 84 Speed sensor, 86 Strainer, 88 HV radiator, 90 Second Medium circulation path 92 the cooling water temperature sensor.

Claims (4)

A mechanical refrigerant pump driven by an internal combustion engine;
An electric refrigerant pump driven by a power source;
A refrigerant pump drive control unit that controls driving of the refrigerant pump so as not to drive the other when driving one of the mechanical refrigerant pump and the electric refrigerant pump;
The refrigerant heat exchanger provided on the discharge side of each refrigerant pump, wherein the refrigerant heat exchanges heat between the first refrigerant discharged from each refrigerant pump and the second refrigerant flowing through the second refrigerant circuit. With an exchange,
Supplying the first refrigerant discharged from one of the mechanical refrigerant pump and the electric refrigerant pump and passing through the refrigerant heat exchanger to the rotating electrical machine to cool the rotating electrical machine;
The refrigerant pump drive control unit drives the mechanical refrigerant pump or the electric refrigerant pump as a drive-side refrigerant pump according to the temperature of the second refrigerant passing through the refrigerant heat exchanger. Rotating electric machine cooling system. In the rotating electrical machine cooling system according to claim 1,
The refrigerant pump drive control unit, on the premise that a predetermined condition set in advance is established, when the temperature of the second refrigerant is equal to or higher than a predetermined threshold temperature, of the mechanical refrigerant pump and the electric refrigerant pump The rotating electrical machine cooling system, wherein the refrigerant pump having a small refrigerant discharge amount is driven as the driving-side refrigerant pump. In the rotating electrical machine cooling system according to claim 1 or 2,
The refrigerant pump drive control unit, on the premise that a predetermined condition set in advance is satisfied, when the temperature of the second refrigerant is lower than a predetermined threshold temperature, of the mechanical refrigerant pump and the electric refrigerant pump The rotating electrical machine cooling system, wherein the refrigerant pump having a large refrigerant discharge amount is driven as the driving-side refrigerant pump. The rotating electrical machine cooling system according to any one of claims 1 to 3,
It is used by being mounted on a vehicle including drive wheels that drive one of the internal combustion engine and the rotating electrical machine as a main drive source,
The refrigerant pump drive control unit drives the drive wheels by an HV traveling mode in which the drive wheels are driven by the power of the internal combustion engine, and the rotating electrical machine that is driven by the electric power from the power source while stopping the internal combustion engine By selectively switching between the EV traveling mode, the driving of the refrigerant pump is controlled so that when one of the mechanical refrigerant pump and the electric refrigerant pump is driven, the other is not driven. Rotating electric machine cooling system.

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