Motor cooling device of hybrid vehicle

Abstract

To provide a motor cooling device of a hybrid vehicle that can adequately control flow volumes of oil for cooling a motor for driving.SOLUTION: A motor cooling device of a hybrid vehicle is provided with: an engine; an MG1 that interlocks with the engine and can generate electric power by driving force of the engine; an MG2 that interlocks with a driving wheel and can generate driving force for running to the driving wheel; a first pump that interlocks with a rotary shaft of the MG1 and supplies oil to the MG1 and MG2; and a second oil pump that interlocks with a rotary shaft of the MG2 and supplies oil to the MG2, which controls flow volumes of oil that is supplied by the first oil pump, by controlling target rotation speed of the MG1 in accordance with a temperature of the MG2.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a motor cooling device for a hybrid vehicle. [Background technology]

[0002] Conventionally, Patent Document 1 proposes a technology that includes a first oil pump connected to the wheels and driven when the vehicle is running, a second oil pump connected to the engine and driven when the engine is operating, a first lubrication / cooling oil passage that guides oil discharged by the first oil pump to an electric motor, and a second lubrication / cooling oil passage that guides oil discharged by the second oil pump to an electric motor and a generator, and that starts the engine and cools the electric motor with oil discharged from the second oil pump when lubrication and cooling by the first oil pump is impossible. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2012-106599 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, while the conventional technology described above can cool the electric motor (hereinafter also referred to as the "drive motor") with the oil discharged from the second oil pump, it has the problem that the flow rate of the oil cooling the drive motor cannot be properly controlled.

[0005] The present invention has been made to solve the above-mentioned problems, and aims to provide a motor cooling device for a hybrid vehicle that can appropriately control the flow rate of oil that cools the drive motor. [Means for solving the problem]

[0006] The motor cooling device for a hybrid vehicle of the present invention is a motor cooling device for a hybrid vehicle that includes an engine, a generator motor linked to the engine and generating electricity using the driving force of the engine, a drive motor linked to drive wheels and capable of generating driving force for driving the drive wheels, a first oil pump linked to the rotating shaft of the generator motor and supplying oil to the generator motor and the drive motor, and a second oil pump linked to the rotating shaft of the drive motor and supplying oil to the drive motor, and is configured to include a control unit that controls the flow rate of oil supplied by the first oil pump in accordance with the temperature of the drive motor. Effect of the Invention

[0007] The present invention can provide a motor cooling device for a hybrid vehicle that can appropriately control the flow rate of oil that cools the drive motor. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram of a vehicle equipped with a motor cooling device for a hybrid vehicle according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a schematic diagram of an oil circulation circuit of a vehicle equipped with a motor cooling device for a hybrid vehicle according to an embodiment of the present invention. [Diagram 3] FIG. 3 is a conceptual diagram showing an example of an MG2 temperature control map referred to by the motor cooling device for a hybrid vehicle according to the embodiment of the present invention. [Figure 4] FIG. 4 is a timing chart showing an example of the state of each part of a vehicle equipped with the motor cooling device for a hybrid vehicle according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] A motor cooling device for a hybrid vehicle according to one embodiment of the present invention includes an engine, a power generation motor that is linked to the engine and generates electricity using the driving force of the engine, a drive motor that is linked to drive wheels and can generate driving force for the drive wheels, a first oil pump that is linked to a rotating shaft of the power generation motor and supplies oil to the power generation motor and the drive motor, and a second oil pump that is linked to a rotating shaft of the drive motor and supplies oil to the drive motor, and is characterized in that the motor cooling device for a hybrid vehicle according to one embodiment of the present invention includes a control unit that controls the flow rate of oil supplied by the first oil pump in accordance with the temperature of the drive motor. As a result, the motor cooling device for a hybrid vehicle according to one embodiment of the present invention can appropriately control the flow rate of oil that cools the drive motor. EXAMPLES

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A vehicle equipped with a motor cooling device for a hybrid vehicle according to an embodiment of the present invention will now be described with reference to the drawings.

[0011] As shown in FIG. 1, the vehicle 1 includes an engine 2, a battery 3, a generator motor 4 (hereinafter also referred to as "MG1"), a first inverter 5, a drive motor 6 (hereinafter also referred to as "MG2"), a second inverter 7, a boost converter 8, drive wheels 9, a first oil pump 10, a second oil pump 11, and a hybrid controller (hereinafter simply referred to as "HCU") 12.

[0012] A plurality of cylinders are formed in the engine 2. In this embodiment, the engine 2 generates power to rotate the MG1 by performing a series of four strokes, which are an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke, for each cylinder.

[0013] The battery 3 is configured by a rechargeable secondary battery, for example a lithium ion battery, and stores the power generated by the MG1 and MG2, and supplies the power to drive the MG1 and MG2.

[0014] The MG1 is provided to be interlocked with the crankshaft of the engine 2. The MG1 is connected to the battery 3 via a first inverter 5 and a boost converter 8. The MG1 has a function of an electric motor that starts the engine 2 by rotating when power is supplied from the battery 3, and a function of a generator that converts the power generated by the engine 2 into electric power.

[0015] The MG2 is provided so as to move in conjunction with drive wheels 9 via a power transmission member such as a gear mechanism. The MG2 is connected to the battery 3 via a second inverter 7 and a boost converter 8.

[0016] The MG2 has a function of an electric motor that rotates the drive wheels 9 by being rotated when supplied with electric power from the battery 3 and the MG1, and a function of a generator that converts the rotational force of the drive wheels 9 into electric power.

[0017] The boost converter 8 is provided between the battery 3 and the first inverter 5 and second inverter 7, and boosts the voltage of the power supplied from the battery 3 to the first inverter 5 and second inverter 7, and lowers the voltage of the power supplied from the first inverter 5 and second inverter 7 to the battery 3.

[0018] The first oil pump 10 is linked to the rotating shaft of MG1 and supplies cooling oil to MG1 and MG2. The second oil pump 11 is linked to the rotating shaft of MG2 and supplies cooling oil to MG2.

[0019] As shown in FIG. 2, the vehicle 1 has an oil pan 21, a strainer 22, an MG1 tank 23, and an MG2 tank 24.

[0020] Oil for cooling MG1 and MG2 is stored in the oil pan 21. The first oil pump 10 and the second oil pump 11 pump up the oil stored in the oil pan 21 through a strainer 22.

[0021] The oil pumped up by the first oil pump 10 is supplied to the MG1 tank 23 and the MG2 tank 24. The oil pumped up by the second oil pump 11 is supplied to the MG2 tank 24.

[0022] The MG1 tank 23 drips the oil supplied by the first oil pump 10 onto the MG1, particularly onto the coil portion of the MG1. The flow rate of the oil dripping from the MG1 tank 23 increases as the flow rate of the oil supplied by the first oil pump 10 increases.

[0023] The MG2 tank 24 drips the oil supplied by the first oil pump 10 and the second oil pump 11 onto the MG2, particularly onto the coil portion of the MG2. The flow rate of the oil dripping from the MG2 tank 24 increases as the flow rate of the oil supplied by the first oil pump 10 and the second oil pump 11 increases.

[0024] The oil dripping from the MG1 tank 23 and the oil dripping from the MG2 tank 24 are collected in the oil pan 21.

[0025] In FIG. 1, the HCU12 is composed of a computer unit having a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory for storing backup data, etc., an input port, and an output port.

[0026] The ROM of this computer unit stores various constants, various maps, and the like, as well as a program for causing the computer unit to function as the HCU 12. That is, the CPU executes the program stored in the ROM using the RAM as a working area, causing the computer unit to function as the HCU 12 in this embodiment.

[0027] An input port of the HCU 12 is connected to various sensors including a temperature sensor 31 for detecting the temperature of MG2 and an MG1 rotation speed sensor 32 for detecting the rotation speed of MG1.

[0028] Various control objects are connected to an output port of the HCU 12, including the first inverter 5, the second inverter 7, the boost converter 8, an injector 41 that supplies fuel to the engine 2, and an ignition plug 42 that ignites in the combustion chamber of the engine 2. When the engine 2 is configured as an engine that does not require an ignition plug, such as a diesel engine, the ignition plug 42 is excluded from the configuration of the vehicle 1.

[0029] The HCU 12 controls various control targets connected to the output port based on information obtained from various sensors connected to the input port. In this embodiment, the HCU 12 functions as a control unit 50 that controls the flow rate of oil supplied by the first oil pump 10 according to the temperature detected by the temperature sensor 31 (hereinafter simply referred to as "MG2 temperature").

[0030] The ROM of the HCU 12 stores a map for controlling the MG2 temperature, in which a target rotation speed of MG1 (hereinafter simply referred to as "target MG1 rotation speed") is associated with a temperature of MG2.

[0031] 3, the MG2 temperature control map is defined so that if the MG2 temperature is equal to or lower than a threshold value TH, the MG1 target rotation speed is 0, and if the MG2 temperature is higher than the threshold value TH, the MG1 target rotation speed becomes higher as the MG2 temperature increases until the MG1 target rotation speed reaches the upper limit of the rotation speed of MG1 (hereinafter simply referred to as the "MG1 upper limit rotation speed") NU. The threshold value TH is set to a temperature at which MG2 does not become overheated.

[0032] In addition, the MG2 temperature control map shown in Figure 3 shows an example in which the MG1 target rotation speed is proportional to the MG2 temperature from the time when the MG2 temperature becomes higher than the threshold value TH until the MG1 target rotation speed becomes the MG1 upper limit rotation speed NU.

[0033] In contrast, in the MG2 temperature control map, the MG1 target rotation speed only needs to be correlated to the MG2 temperature so that it monotonically increases in accordance with the performance of the first oil pump 10, etc., from the time when the MG2 temperature becomes higher than the threshold value TH until the MG1 target rotation speed becomes the MG1 upper limit rotation speed NU.

[0034] For example, in the MG2 temperature control map, the MG1 target rotation speed may be associated with the MG2 temperature so that the rate of increase of the MG1 target rotation speed becomes higher as the MG2 temperature increases during the period from when the MG2 temperature becomes higher than a threshold value TH until the MG1 target rotation speed becomes the MG1 upper limit rotation speed NU.

[0035] The HCU 12 controls the rotation speed of MG1 based on the MG2 temperature control map, thereby controlling the flow rate of oil supplied by the first oil pump 10. That is, when the MG2 temperature becomes higher than the threshold value TH, the HCU 12 starts the engine 2 and controls the rotation speed of the engine 2 so that the rotation speed of MG1 detected by the MG1 rotation speed sensor 32 becomes the MG1 target rotation speed.

[0036] When starting the engine 2, the HCU 12 controls the first inverter 5 to drive the MG1 so that the rotational speed of the MG1 becomes the MG1 target rotational speed, thereby rotating the crankshaft of the engine 2, and starts the supply of fuel by the injector 41 and ignition by the spark plug 42.

[0037] When the engine 2 starts, the HCU 12 controls the rotation speed of the MG1 to become a target MG1 rotation speed by adjusting the intake air amount of the engine 2, the amount of fuel injected by the injector 41, and the ignition timing by the spark plug 42, etc.

[0038] The state of each part of the vehicle 1 configured as above will be described with reference to Fig. 4. Fig. 4 shows, from the top, the flow rate of oil dripping onto MG2 (referred to as "oil flow rate" in the figure), the rotation speed of MG1 (referred to as "MG1 rotation speed" in the figure), and the transition of MG2 temperature.

[0039] In addition, the oil flow rate indicated by the solid line indicates the oil flow rate by the second oil pump 11, the oil flow rate indicated by the dashed line indicates the oil flow rate by the first oil pump 10, and the oil flow rate indicated by the dashed line indicates the oil flow rate obtained by adding the oil flow rate by the second oil pump 11 to the oil flow rate by the first oil pump 10.

[0040] 4, until time t1, the MG2 temperature is equal to or lower than the threshold value TH, and therefore oil pumped up only by the second oil pump 11 is dripped into MG2. When the MG2 temperature exceeds the threshold value TH at time t1, the HCU 12 controls the MG1 rotation speed to the MG1 target rotation speed based on the MG2 temperature control map, and in addition to the oil pumped up only by the second oil pump 11, oil pumped up by the first oil pump 10 is dripped into MG2.

[0041] When the MG2 temperature becomes equal to or lower than the threshold value TH at time t2, the HCU 12 controls the MG1 to stop, and the oil pumped up only by the second oil pump 11 is dripped into the MG2.

[0042] As described above, the motor cooling device for a hybrid vehicle according to this embodiment controls the flow rate of oil supplied by the first oil pump 10 in accordance with the MG2 temperature, and therefore can appropriately control the flow rate of oil cooling MG2.

[0043] For example, the motor cooling device of the hybrid vehicle in this embodiment controls the flow rate of oil supplied by the first oil pump 10 in accordance with the MG2 temperature, thereby preventing the flow rate of oil cooling MG2 from becoming excessive during high-speed driving, thereby preventing a deterioration in fuel efficiency.

[0044] In addition, the motor cooling device of the hybrid vehicle of this embodiment controls the flow rate of oil supplied by the first oil pump 10 in accordance with the MG2 temperature, thereby preventing a shortage of the flow rate of oil cooling MG2 during low-speed driving, thereby enabling MG2 to be sufficiently cooled.

[0045] In this way, the motor cooling device of the hybrid vehicle of this embodiment can sufficiently cool MG2 while preventing a deterioration in fuel efficiency by controlling the flow rate of oil supplied by the first oil pump 10 in accordance with the MG2 temperature.

[0046] Furthermore, the motor cooling device for a hybrid vehicle according to this embodiment controls the rotation speed of MG1 to be higher as the temperature of MG2 becomes higher, so that MG2 can be sufficiently cooled while preventing a deterioration in fuel efficiency.

[0047] In addition, the motor cooling device for a hybrid vehicle according to this embodiment controls MG1 to be driven when the MG2 temperature is higher than the threshold value TH, so that MG2 can be sufficiently cooled while preventing a deterioration in fuel efficiency.

[0048] In the embodiment described above, an example was described in which, when the MG2 temperature becomes higher than the threshold value TH, the HCU 12 starts the engine 2, controls the rotation speed of the engine 2, and controls the rotation speed of the MG1 that is linked to the engine 2.

[0049] On the other hand, when the MG2 temperature becomes higher than the threshold value TH, the HCU 12 may control the first inverter 5 to drive the MG1 and control the rotation speed of the MG1.

[0050] In addition, when the MG2 temperature becomes higher than the threshold value TH, the HCU12 may selectively execute a first process of starting the engine 2, controlling the rotation speed of the engine 2, and controlling the rotation speed of the MG1 linked to the engine 2, and a second process of controlling the first inverter 5 to drive the MG1 and control the rotation speed of the MG1.

[0051] For example, when the MG2 temperature becomes higher than the threshold TH, the HCU 12 may execute the first process if the remaining capacity of the battery 3 is less than the low charge determination threshold, and execute the second process if the remaining capacity of the battery 3 is equal to or greater than the low charge determination threshold. The low charge determination threshold is set to a value at which the battery 3 is determined to be in a low charge state.

[0052] In addition, in a state in which the MG2 temperature is higher than the threshold value TH and the engine 2 is thereby caused to drive the MG1, the HCU 12 may or may not cause the MG1 to generate electricity by controlling the first inverter 5.

[0053] For example, in a state in which the engine 2 is driving the MG1 because the MG2 temperature is higher than the threshold TH, the HCU 12 may control the first inverter 5 to cause the MG1 to generate power if the remaining capacity of the battery 3 is less than the high charge determination threshold, and may control the first inverter 5 to prevent the MG1 from generating power if the remaining capacity of the battery 3 is equal to or greater than the high charge determination threshold. The high charge determination threshold is set to a value at which the battery 3 is determined to be in a high charge state.

[0054] Furthermore, the above-mentioned threshold value TH, low charging determination threshold value, and high charging determination threshold value may each be determined with hysteresis so as to suppress frequent switching of the driving states of the engine 2 and MG1 in a short period of time.

[0055] Furthermore, the HCU 12 may set a condition for prohibiting the first oil pump 10 from supplying oil or for restricting the amount of oil supplied depending on the situation. For example, the HCU 12 may set a condition that the engine is cold, for example, for prohibiting the first oil pump 10 from supplying oil or for restricting the amount of oil supplied. With this configuration, it is possible to improve fuel efficiency by promoting an increase in the temperature of the oil dripped onto the MG2 during a cold engine, thereby reducing friction.

[0056] While the present invention has been disclosed by way of example, it will be apparent that modifications may be made to the present invention without departing from the spirit and scope of the present invention, and the present invention is disclosed with the understanding that equivalents of such modifications are intended to be included within the scope of the invention as defined by the appended claims. [Explanation of symbols]

[0057] 1 vehicle (hybrid vehicle) 2. Engine (internal combustion engine) 4. Generator motor 6 Driving motor 9 Drive wheels 10 No. 1 oil pump 11 No. 2 oil pump 50 Control section

Claims

1. The engine, a power generating motor that is linked to the engine and generates power using the driving force of the engine; A drive motor that is linked to a drive wheel and is capable of generating a drive force for running on the drive wheel; a first oil pump that is linked to a rotating shaft of the power generation motor and supplies oil to the power generation motor and the drive motor; a second oil pump that is linked to a rotary shaft of the drive motor and supplies oil to the drive motor, A motor cooling device for a hybrid vehicle, comprising: a control unit that controls a flow rate of oil supplied by the first oil pump in accordance with a temperature of the drive motor.

2. The control unit is 2. The motor cooling device for a hybrid vehicle according to claim 1, wherein the rotational speed of the generator motor is controlled so as to increase as the temperature of the drive motor increases.

3. The control unit is 3. The motor cooling device for a hybrid vehicle according to claim 2, wherein the motor cooling device controls the generator motor to be driven when the temperature of the drive motor is higher than a threshold value.

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